CN101091368B - Method and device for transmitting/receiving signals in fast frequency hopping OFDM communication system - Google Patents

Abstract

The device of the present invention includes: a fast frequency hopping unit, configured to allocate input data to several subcarriers selected from a plurality of subcarriers, and to perform fast frequency hopping according to a fast frequency hopping pattern to generate an FFH signal, wherein one or more The slice data includes input data and each of the slice or slices of data is allocated to a selected subcarrier; the FFT unit is used to perform FFT on the FFH signal; the controller is used to insert null data into the remaining subcarriers In the carrier, the remaining subcarriers include subcarriers other than the selected subcarriers; the first inverse FFT unit is used to perform both the selected subcarriers including input data and the remaining subcarriers including inserted null data. or performing IFFT to generate a first IFFT signal; and a transmitter for transmitting the first IFFT signal.

Description

Method and device for transmitting/receiving signals in fast frequency hopping OFDM communication system

technical field

The present invention relates to a communication system (FFH-OFDM communication system) using a Fast Frequency Hopping (FFH) scheme and an Orthogonal Frequency Division Multiplexing (OFDM) scheme. More particularly, the present invention relates to a method and system for transmitting/receiving signals by using only a subset of all available frequency bands used in an FFH-OFDM communication system.

Background technique

In a fourth generation (4G) communication system, services that are provided to users with various qualities of service (QoS) and that support high transmission speeds have been actively researched. In addition, research and development of new communication systems capable of supporting high-speed services and ensuring mobility and QoS in wireless Local Area Network (LAN) and Metropolitan Area Network (MAN) systems have been actively conducted.

In order to support a broadband transmission network for physical channels of a wireless MAN system, an OFDM scheme and an Orthogonal Frequency Division Multiple Access (OFDMA) scheme are being widely used. The OFDM/OFDMA scheme can realize high-speed data transmission by using multiple carriers when transmitting a physical channel signal, and can obtain frequency diversity gain by using different subcarrier frequency bands of a frequency band used for signal transmission.

Compared with a system using a single subcarrier, an OFDM communication system using multiple subcarriers has a symbol period prolonged in proportion to the number of subcarriers with respect to the transmission speed of the same data. By using a guard interval, an OFDM communication system can reduce inter-symbol interference (ISI) in a wireless channel with multipath fading. Methods for inserting guard intervals include a cyclic prefix method and a cyclic suffix method. In the cyclic prefix method, a predetermined number of samples at the end of the OFDM symbol in the time domain are copied and inserted into an effective OFDM symbol. In the cyclic suffix method, a predetermined number of samples of the first of an OFDM symbol in the time domain are copied and inserted into an effective OFDM symbol.

可以在一个OFDM码元周期期间减少载波间干扰(ICI)。当子载波彼此正交并且在它们之间不存在干扰时。OFDM通信系统的接收机能够通过使用具有相对简单的结构的单抽头均衡器来解调数据。进一步，OFDM通信系统能够最小化系统的复杂度，这是因为OFDM通信系统使用快速逆傅立叶变换(IFFT)方案和快速傅立叶变换(FFT)方案来调制/解调多个子载波。在OFDM系统中使用IFFT方案的快速逆傅立叶变换单元(IFFT单元)的操作对应于频率调制，可以将其表示为如下面公式(1)所定义的矩阵D_Q。Further, the channel response of each sub-carrier band is approximated to be flat within that sub-carrier band. Moreover, by setting the difference Δf between subcarriers to be the reciprocal of the sampling time T _s

Inter-Carrier Interference (ICI) can be reduced during one OFDM symbol period. When the subcarriers are orthogonal to each other and there is no interference between them. A receiver of an OFDM communication system can demodulate data by using a one-tap equalizer having a relatively simple structure. Further, the OFDM communication system can minimize system complexity because the OFDM communication system modulates/demodulates a plurality of subcarriers using an inverse fast Fourier transform (IFFT) scheme and a fast Fourier transform (FFT) scheme. The operation of an inverse fast Fourier transform unit (IFFT unit) using an IFFT scheme in an OFDM system corresponds to frequency modulation, which can be represented as a matrix _DQ as defined by equation (1) below.

${<span\; class="notranslate">\; [</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}<span\; class="notranslate">\; ]</span>}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\sqrt{\mathrm{<span\; class="notranslate">\; Q</span>}}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; exp</span>}<span\; class="notranslate">\; \{</span>\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="j"\; filenames="H2005800450661E00051.png"\; state="\{\{state\}\}">j</figure-callout></span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\frac{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; Q</span>}}<span\; class="notranslate">\; \}</span><span\; class="notranslate">\; ]</span><span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

In formula (1), Q represents the number of all subcarriers used in the OFDM communication system, n represents a sample index, and m represents a subchannel index. D _Q denotes an IFFT matrix having a size of Q×Q. A subchannel refers to a channel including at least one subcarrier. Further, the operation of Fast Fourier Transform (FFT) using the FFT scheme can be expressed as the Hermitian conjugate (Hermitian) D _Q ^H of the IFFT matrix D _Q as defined by equation (1).

Meanwhile, when a plurality of subcarriers in an OFDM communication system include subcarriers undergoing deep fading, the probability that data transmitted by the subcarriers undergoing deep fading can be successfully decoded by a receiver is low. Schemes that have been proposed to overcome performance degradation due to deep fading include a frequency hopping scheme and a forward error correction (FEC) scheme.

The frequency hopping scheme is a scheme in which a frequency band used for signal transmission is changed according to a predetermined frequency hopping pattern so that an average gain of Inter-Cell Interference (ICI) can be obtained. In other words, according to the frequency hopping scheme, while transmitting a signal, a transmission frequency band for a subcarrier is periodically changed according to a predetermined frequency hopping pattern. Therefore, the frequency hopping scheme can prevent signals from being continuously transmitted to signal users through subcarriers experiencing deep fading due to frequency-selective channel characteristics. The frequency hopping period is a time interval corresponding to the OFDM symbol time or an integer multiple of OFDM symbols. As a result, in the case of using the frequency hopping scheme, even when a signal is transmitted through a subcarrier undergoing deep fading at a predetermined OFDM symbol time, a signal can also be transmitted through a subcarrier not undergoing deep fading at the next OFDM symbol time , so that signal transmission is continuously affected by deep fading, so that frequency diversity gain and interference can be averaged.

Further, according to the FH-OFDM scheme which is a combination of the frequency hopping scheme and the OFDM scheme, different subchannels are allocated to users, and subchannels allocated to users undergo frequency hopping. This makes it possible to obtain average diversity gain and ICI average gain.

However, in order to obtain sufficient gain through the frequency hopping scheme, conventional OFDM communication systems must perform frequency hopping during many OFDM symbol time periods. Further, it requires a large number of users, and an appropriate frequency hopping pattern must be selected according to the channel. Even further, in a conventional OFDM communication system using a frequency hopping scheme, although the signal is not continuously transmitted to a single user through a subcarrier experiencing deep fading, it is also possible for the receiver to demodulate the signal generated by Signals carried by subcarriers that experience deep fading.

Therefore, there is a need for an improved method for transmitting/receiving signals by using only a subset of all available frequency bands used in FFH-OFDM communication systems, so that a receiver can demodulate signals transmitted by subcarriers experiencing deep fading Methods and equipment.

Contents of the invention

An aspect of the present invention is to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, aspects of example embodiments of the present invention provide methods and apparatuses for transmitting/receiving signals in an FFH-OFDM communication system.

Another object of example embodiments of the present invention is to provide a method and apparatus for transmitting/receiving signals by using only a subset of all available frequency bands used in an FFH-OFDM communication system.

In order to achieve this object, there is provided an apparatus for signal transmission in a fast frequency hopping-orthogonal frequency division multiplexing (FFH-OFDM) communication system that divides all available frequency bands into a plurality of sub-bands and includes each A plurality of sub-channels each comprising at least one sub-carrier frequency band, the device comprising: a fast frequency hopping (FFH) unit for distributing input data to several sub-carriers selected from the plurality of sub-carriers, and for Frequency mode is used to perform fast frequency hopping to generate FFH signals, wherein one or more slices of data include input data and each of the one or more slices of data is assigned to a selected subcarrier; Fast Fourier Transform (FFT) unit, with for performing FFT on the FFH signal; a controller for inserting null data into remaining subcarriers including subcarriers other than the selected subcarrier; a first inverse fast Fourier transform (IFFT) unit for performing IFFT on both the selected subcarriers including the input data and the remaining subcarriers including the inserted null data to generate a first IFFT signal; and a transmitter for transmitting the first IFFT signal.

According to another aspect of an exemplary embodiment of the present invention, there is provided a method for signal transmission in a fast frequency hopping-orthogonal frequency division multiplexing (FFH-OFDM) communication system that divides all available frequency bands being a plurality of sub-bands and comprising a plurality of sub-channels each comprising at least one sub-carrier frequency band, the method comprising the steps of: allocating input data to a number of sub-carriers selected from the plurality of sub-carriers, and for performing fast frequency hopping (FFH) to generate an FFH signal in which one or more slices of data comprise the input data and assigning each of the one or more slices of data to a selected subcarrier; performing a fast Fourier transform (FFT) on the FFH signal ); inserting null data into the remaining subcarriers, the remaining subcarriers including subcarriers other than the selected subcarriers; both the selected subcarriers including the input data and the remaining subcarriers including the inserted null data or performing IFFT to generate a first IFFT signal; and passing through an inverse fast Fourier transform (IFFT) unit the converted signal that has been subjected to the IFFT.

According to another aspect of an example embodiment of the present invention, there is provided an apparatus for signal transmission in a fast frequency hopping-orthogonal frequency division multiplexing (FFH-OFDM) communication system that divides all available frequency bands being a plurality of sub-bands and comprising a plurality of sub-channels each comprising at least one sub-carrier frequency band, the apparatus comprising: a first Fast Fourier Transform (FFT) unit configured to perform an FFT on a received signal; a controller configured to to separate the remaining subcarriers from the FFT-processed signal in the first FFT unit, the remaining subcarriers including subcarriers other than a selected number of subcarriers through which the transmitting device transmits data, and then inserting null data into In the remaining sub-carriers; the first equalizer is used to equalize the output signal of the controller in the frequency domain; the fast inverse Fourier transform (IFFT) unit is used to perform the first equalizer according to the fast frequency hopping matrix applied by the transmission device. performing an IFFT on the equalized signal; a second equalizer for equalizing the IFFT processed signal in the time domain; and a second fast Fourier transform (FFT) unit for performing an FFT on the equalized signal in the time domain .

According to another aspect of an exemplary embodiment of the present invention, there is provided a method for signal transmission in a fast frequency hopping-orthogonal frequency division multiplexing (FFH-OFDM) communication system that divides all available frequency bands For a plurality of sub-bands and including a plurality of sub-channels each comprising at least one sub-carrier frequency band, the method comprises the steps of: (1) performing a Fast Fourier Transform (FFT) on a received signal; separating the remaining subcarriers from the FFT-processed signal in the FFT unit, the remaining subcarriers including subcarriers other than the selected subcarriers through which the transmitting device transmits data, and then inserting null data into the remaining subcarriers; (3) equalize the signal generated by step (2) in the frequency domain; (4) perform a fast inverse Fourier transform (IFFT) on the equalized signal in the frequency domain according to the fast frequency hopping matrix; (5) perform a fast inverse Fourier transform (IFFT) in the time domain medium equalizing the IFFT processed signal; and (6) performing a Fast Fourier Transform (FFT) on the equalized signal in the time domain.

According to another aspect of an example embodiment of the present invention, there is provided an apparatus for signal transmission in a fast frequency hopping-orthogonal frequency division multiplexing (FFH-OFDM) communication system that divides all available frequency bands being a plurality of sub-bands and comprising a plurality of sub-channels each comprising at least one sub-carrier frequency band, the apparatus comprising: a first controller for inserting null data into remaining sub-carriers included in all available sub-carriers subcarriers other than the selected ones over which the input data is carried; a fast frequency hopping (FFH) unit for allocating input data to the selected ones and for assigning the input data to the selected ones according to the fast The frequency hopping mode performs fast frequency hopping to generate an FFH signal, wherein one or more pieces of data comprise input data and each of the one or more pieces of data is assigned to a selected subcarrier; a fast Fourier transform (FFT) unit, with for performing FFT on FFH; a second controller for inserting null data into the remaining subcarriers; a first inverse Fast Fourier Transform (IFFT) unit for performing the selected subcarriers including input data and including the inserted performing IFFT on both remaining subcarriers of the null data to generate a first IFFT signal; and a transmitter for transmitting the first IFFT signal.

According to another aspect of an exemplary embodiment of the present invention, there is provided a method for signal transmission in a fast frequency hopping-orthogonal frequency division multiplexing (FFH-OFDM) communication system that divides all available frequency bands being a plurality of sub-bands and comprising a plurality of sub-channels each comprising at least one sub-carrier frequency band, the method comprising the steps of: (1) inserting null data into remaining sub-carriers included in all available sub-carriers subcarriers other than the selected subcarriers through which the input data is carried; (2) allocating the input data to the selected subcarriers and then performing fast frequency hopping according to a fast frequency hopping pattern to generate the FFH signal, One or more pieces of data include input data and each of the one or more pieces of data is assigned to a selected subcarrier; (3) perform fast Fourier transform (FFT) on FFH; (4) insert null data into Of the remaining subcarriers; (5) performing an inverse fast Fourier transform on both the selected subcarriers including the input data and the remaining subcarriers including the inserted null data to generate a first IFFT signal; and (6) transmitting the first IFFT signal.

According to another aspect of an example embodiment of the present invention, there is provided an apparatus for signal transmission in a fast frequency hopping-orthogonal frequency division multiplexing (FFH-OFDM) communication system that divides all available frequency bands being a plurality of sub-bands and comprising a plurality of sub-channels each comprising at least one sub-carrier frequency band, the apparatus comprising: a first Fast Fourier Transform (FFT) unit for performing an FFT on a received signal; a first controller , used to separate the remaining subcarriers from the FFT-processed signal in the first FFT unit, the remaining subcarriers include subcarriers other than a few selected subcarriers through which the transmitting device transmits data, and then empty The data is inserted into the remaining subcarriers; the first equalizer is used to equalize the output signal of the controller in the frequency domain; the fast inverse Fourier transform (IFFT) unit is used to pass through the second A signal equalized by an equalizer performs IFFT; a second equalizer is used to equalize the signal through the IFFT in the time domain; a second fast Fourier transform (IFFT) unit is used to perform FFT on the signal equalized in the time domain; and a second controller, configured to separate the remaining subcarriers from the FFT-processed signal in the second FFT unit, and then insert null data into the remaining subcarriers.

According to another aspect of an exemplary embodiment of the present invention, there is provided a method for signal transmission in a fast frequency hopping-orthogonal frequency division multiplexing (FFH-OFDM) communication system that divides all available frequency bands For a plurality of sub-bands and including a plurality of sub-channels each comprising at least one sub-carrier frequency band, the method comprises the steps of: (1) performing FFT on the received signal; (2) passing through the first FFT unit Separate the remaining subcarriers from the FFT-processed signal, the remaining subcarriers including subcarriers other than a few selected subcarriers through which the transmitting device transmits data, and then insert null data into the remaining subcarriers; (3) balance Controlling the signal generated in step (2); (4) performing fast inverse Fourier transform (IFFT) on the signal equalized in the frequency domain according to the fast frequency hopping matrix; (5) equalizing the signal through the IFFT in the time domain; (6) performing Fast Fourier Transform (FFT) on the signal equalized in the time domain; (7) separating the remaining subcarriers from the FFT-processed signal in the second FFT unit, and then inserting null data into the remaining subcarriers in the subcarrier.

According to another aspect of an example embodiment of the present invention, there is provided an apparatus for signal transmission in a fast frequency hopping-orthogonal frequency division multiplexing (FFH-OFDM) communication system that divides all available frequency bands being a plurality of sub-bands and comprising a plurality of sub-channels each comprising at least one sub-carrier frequency band, the device comprising: a first fast frequency hopping-OFDM (FFH-OFDM) processing unit for processing the sub-channels to be transmitted by each user The signal performs fast frequency hopping and converts the signal into an OFDM signal, the FFH-OFDM processing unit includes a plurality of processors, each of which distributes input data to several subcarriers selected from a plurality of subcarriers and is used for Frequency mode performs fast frequency hopping to generate FFH-OFDM signals, wherein one or more pieces of data include input data and the one or more pieces of data are allocated to a selected subcarrier; multiplexer for multiplexing FFH-OFDM a signal; an inverse fast Fourier transform (IFFT) unit for performing an IFFT on the multiplexed signal; and a transmitter for transmitting the IFFTed signal.

Other objects, advantages and salient features of the present invention will become apparent to those skilled in the art from the following detailed description disclosing exemplary embodiments of the present invention in conjunction with the accompanying drawings.

Description of drawings

The above and other objects, features and advantages of specific embodiments of the present invention will become more apparent to those skilled in the art from the following detailed description taken in conjunction with the accompanying drawings.

FIG. 1 is a block diagram showing a structure of a transmitter of an FFH-OFDM communication system performing a function according to a first exemplary embodiment of the present invention;

2 is a block diagram showing a structure of a receiver of an FFH-OFDM communication system that performs functions according to a first exemplary embodiment of the present invention;

3 is a block diagram showing a structure of a transmitter of an FFH-OFDM communication system performing a function according to a second exemplary embodiment of the present invention;

4 is a block diagram showing a structure of a receiver of an FFH-OFDM communication system performing functions according to a second exemplary embodiment of the present invention;

5 is a block diagram showing a structure of a transmitter of an FFH-OFDM communication system performing a function according to a third exemplary embodiment of the present invention;

6 is a block diagram showing a structure of a receiver of an FFH-OFDM communication system that performs functions according to a third exemplary embodiment of the present invention; and

7 is a block diagram showing a structure of a transmitter in a fast frequency hopping OFDM communication system, which performs a function according to a fourth embodiment of the present invention.

It should be understood that like reference numerals represent like elements, features and structures throughout the drawings.

Detailed ways

Matters defined in this specification, such as detailed construction and constituent parts, are provided to help in a comprehensive understanding of the present invention, and are exemplary only. Accordingly, those of ordinary skill in the art will recognize that various modifications and variations of the embodiments described herein can be made without departing from the scope and spirit of the invention. Also, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

Exemplary embodiments of the present invention include methods and apparatus for using only the communication system (FFH-OFDM communication system) using the Fast Frequency Hopping (FFH) scheme and the Orthogonal Frequency Division Multiplexing (OFDM) scheme Subset of all available frequency bands, transmit/receive signals while performing fast frequency hopping. The FFH frequency hopping scheme is a scheme in which fast frequency hopping is performed in a cycle of OFDM samples, or in integer multiples of OFDM samples instead of the OFDM sample cycle. Therefore, according to the FFH frequency hopping scheme, one OFDM symbol is transmitted after being spread to a plurality of subcarriers in the frequency domain.

A structure of a transmitter that performs fast frequency hopping by using all available frequency bands in an FFH-OFDM communication system will be described with reference to FIG. 1 .

FIG. 1 is a block diagram showing a structure of a transmitter of an FFH-OFDM communication system according to a first exemplary embodiment of the present invention.

1, the transmitter includes a serial to parallel (S/P) converter 111, a fast frequency hopping (FFH) unit 120, a parallel to serial (P/S) converter 131, a guard interval inserter 133, a digital to An analog (D/A) converter 135 and a radio frequency (RF) processor 137 . The FFH unit 120 includes an inverse fast Fourier transform (IFFT) unit 121 and a linear processor 123 .

When there is input data to be transferred, the input data is input to the S/P converter 111 . This data includes actual user data or reference data such as pilots. The S/P converter 111 converts input data symbols into parallel signals, and outputs the converted parallel data to the IFFT unit 121 . As used herein, the parallel signal output from the S/P converter 111 is referred to as d , which is defined by the following formula (2).

d = [d ₁ ...d _Q ] ^T ..........(2)

In formula (2), T represents a transpose operation, and Q represents the total number of available subcarriers used in the FFH-OFDM communication system. The IFFT unit 121 performs Q-point IFFT on the signal d output from the S/P converter 111 , and outputs the IFFT-processed signal to the linear processor 123 . The linear processor 123 performs linear processing on the signal from the IFFT unit 121 and then outputs the processed signal to the P/S converter 131 .

Next, the operations of the IFFT unit 121 and the linear processor 123 will be described in more detail.

When fast frequency hopping is performed on subcarriers, in order to transmit data at time intervals corresponding to the OFDM sample time period or multiples of the OFDM sample time period in the transmitter shown in Figure 1 using all available frequency bands, one can pass A new matrix G _Q of size Q×Q is used to represent the frequency modulation. In other words, the matrix used to perform frequency modulation according to the fast frequency hopping scheme (hereinafter, referred to as "fast frequency hopping matrix") as defined in the following formula (3) is different from that described in the prior art description by the formula (1) The defined IFFT matrix D _Q is different. As described above, the IFFT matrix D _Q is a matrix corresponding to the frequency modulation operation of the IFFT unit.

${<span\; class="notranslate">\; [</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; G</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}<span\; class="notranslate">\; ]</span>}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\sqrt{\mathrm{<span\; class="notranslate">\; Q</span>}}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; exp</span>}<span\; class="notranslate">\; \{</span>\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="j"\; filenames="H2005800450661E00051.png"\; state="\{\{state\}\}">j</figure-callout></span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\frac{{<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; \&Phi;</span>}<span\; class="notranslate">\; ]</span>}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}}}{\mathrm{<span\; class="notranslate">\; Q</span>}}<span\; class="notranslate">\; \}</span><span\; class="notranslate">\; ]</span><span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

In Equation (3), n represents a sample index, and m represents a subchannel index. Further, [Φ] _n,m represents the subcarrier transmitting the data of the mth subchannel on the nth sample. Therefore, [Φ] _n,m determines the fast frequency hopping pattern when fast frequency hopping is performed. Further, exemplary embodiments of the present invention use a fast frequency hopping pattern, which can prevent subcarriers used for data transmission from overlapping on predetermined samples, and the fast frequency hopping used for all fast frequency hopping patterns is represented by the following formula (4) Matrix G _Q .

G _Q ＝ Δ _Q D _Q ， Δ _Q ＝ G _Q D _Q ^H ..........(4)

In formula (4), values of elements of the fast hopping matrix G _Q and the matrix Δ _Q are predetermined according to the fast hopping pattern, and the matrix Δ _Q has a size of Q×Q.

Assuming that f _n of the fast frequency hopping pattern is the subcarrier that transmits the data of the first subchannel on the nth sample, when the matrix Δ _Q of the formula (4) is generated by using the cyclic fast frequency hopping pattern defined by the following formula (5) , it always becomes a diagonal matrix.

[Φ] _{n, m} = mod(f _n + m-1, Q), m = 1, ..., Q...........(5)

In this case, the fast hopping matrix G _Q is expressed _as a product obtained by multiplying the ordinary IFFT matrix D _Q by the matrix ΔQ . Thus, the device for performing fast frequency hopping can be implemented by an IFFT unit and _a linear processor capable of multiplying the IFFT matrix by the matrix ΔQ . As described herein, example embodiments of the present invention are based on the assumption that fast hopping patterns are examples of cyclic fast hopping patterns. Therefore, _the matrix ΔQ can also be defined as a diagonal matrix. It goes without saying that this also holds true in the case of a modification of the type of fast frequency hopping pattern.

As used herein, the signal output from linear processor 123 is referred to as b . The signal b is defined by the following formula (6).

b ＝ G _Q d ＝ Δ _Q D _Q d ..........(6)

The P/S converter 131 receives the signal b from the linear processor 123 , converts the signal b into a serial signal, and then outputs the converted serial signal to the guard interval inserter 133 . Guard interval inserter 133 inserts a guard interval into the signal output from P/S converter 131 , and then outputs the signal to D/A converter 135 . The guard interval is inserted to remove interference between a previous OFDM symbol transmitted at a previous OFDM symbol time and a current OFDM symbol to be transmitted at a current OFDM symbol time in an OFDM communication system. Further, a cyclic prefix method or a cyclic postfix method is used to insert a guard interval. In the cyclic prefix method, a predetermined number of last samples of an OFDM symbol in the time domain are replicated and inserted into a valid OFDM symbol. In the cyclic suffix method, a predetermined number of leading samples of an OFDM symbol in the time domain are copied and inserted into a valid OFDM symbol.

The D/A converter 135 converts the signal output from the guard interval inserter 133 into an analog signal, and then outputs the converted signal to the RF processor 137 . The RF processor 137 includes elements such as filters and front-to-back units. The RF processor 137 performs RF processing on the signal output from the D/A converter 135, and transmits the processed signal through an actual channel.

Next, the structure of the receiver of the FFH-OFDM communication system performing the function according to the first embodiment of the present invention will be described with reference to FIG. 2 .

2 is a block diagram of a structure of a receiver of an FFH-OFDM communication system performing functions according to a first exemplary embodiment of the present invention.

The receiver shown in FIG. 2 includes an RF processor 211, a D/A converter 213, a channel estimator 215, a guard interval remover 217, an S/P converter 219, an FFT unit 221, an equalizer 223, an IFFT unit 225, An equalizer 227 , an FFT unit 229 and a parallel-to-serial (P/S) converter 231 .

The signal transmitted from the transmitter of the FFH-OFDM communication system shown in FIG. 1 picks up noise such as additive white noise (AWGN) while passing through the multipath channel, and then has the added noise The signal is input to the RF processor 211 through the antenna. As used herein, denote the channel matrix representing the channel response of the multipath channel as H _t and the added noise as n _t , where t means that the channel response and noise are measured in the time domain. The RF processor 211 down-converts a signal received through an antenna into an intermediate frequency (IF) signal and then a baseband frequency signal, and then outputs the converted signal to the D/A converter 213 . The D/A converter 213 converts the analog signal output from the RF processor 211 into a digital signal, and then outputs the converted digital signal to the channel estimator 215 and the guard interval remover 217 .

The channel estimator 215 performs channel estimation on the signal from the D/A converter 213 and outputs the result of the channel estimation to the equalizer 223 . The channel estimation operation of the channel estimator 215 is not directly related to the exemplary embodiment of the present invention, and thus will not be described in detail. The guard interval remover 217 removes a guard interval from the signal input from the D/A converter 213 and outputs the resulting signal to the S/P converter 219 . The S/P converter 219 converts the signal from the guard interval remover 217 into a parallel signal, and outputs the converted parallel signal to the FFT unit 221 . As used herein, the signal output from the S/P converter 219 is referred to as e . Signal e is a time-domain signal defined by the following formula (7).

e = H _t B + n _t ...................(7)

The FFT unit 221 performs Q-point FFT on the signal e from the S/P converter 219 , and then outputs the signal to the equalizer 223 . As used herein, the signal output from the FFT unit 221 is referred to as ef _. The signal e _f is a frequency domain signal defined by the following formula (8).

${\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; e</span>}}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; =</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; =</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}}_{\mathrm{<span\; class="notranslate">\; t</span>}}\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; b</span>}}<span\; class="notranslate">\; +</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; no</span>}}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span>$

In formula (8), D _Q ^H represents the Hermitian conjugate of the IFFT matrix D _Q.

In order to compensate for the signal distortion of the multipath channel, an equalization operation needs to be performed. In particular, in an FFH-OFDM communication system, equalization needs to be performed in both the time domain and the frequency domain. Therefore, the FFH-OFDM communication system requires two kinds of equalizers, including a time-domain equalizer for equalizing time-domain signals and a frequency-domain equalizer for equalizing frequency-domain signals.

Therefore, the equalizer 223 equalizes the signals from the FFT unit 221 in the frequency domain, and then outputs them to the IFFT unit 225 . The equalizer 223 compensates the channel response in the frequency domain. Since the FFH-OFDM communication system uses a guard interval signal, the channel response in the time domain and the channel response in the frequency domain are in a singular value decomposition (Singular Value Decomposition) relationship, which is defined by the following formula (9).

${\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; =</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}}_{\mathrm{<span\; class="notranslate">\; t</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span>$

In Equation (9), H _f represents a channel matrix that compensates for a channel response in the frequency domain. Since the channel matrix H _f is a diagonal matrix, it can be implemented by a one-tap equalizer. The equalizer 223 for performing frequency domain equalization performs substantially the same operation as that performed by an equalizer of a typical OFDM communication system. The equalizer 223 has a structure including a Zero Forcing (ZF) equalizer, a Minimum Mean Square Error (MMSE) equalizer, and a matched filter according to a channel compensation scheme.

Further, the IFFT unit 225 performs Q-point IFFT on the signal from the equalizer 223 , and then outputs the signal to the equalizer 227 . The operation of the IFFT unit 225 is the same as that of the IFFT unit 121 of the transmitter shown in FIG. 1, so a detailed description thereof is omitted here.

The equalizer 227 receives the signal from the IFFT unit 225 , equalizes the signal in the time domain, and then outputs the signal to the FFT unit 229 . As used herein, the equalization of the signal in the time domain is _denoted Mt. The equalization M _t in the time domain can be defined by the following formula (10).

M _t = ΔQ _H ................................(10 ⁾

As represented by formula (10), the equalization M _t in the time domain can be represented by the Hermitian conjugate Δ _Q ^H of the matrix Δ _Q defined by formula (4). Therefore, _the matrix ΔQ ^H is also a diagonal matrix.

来表示从FFT单元229输出的信号。The FFT unit 229 receives the signal from the equalizer 227 , performs Q-point FFT on the information, and then outputs the signal to the P/S converter 231 . The operation of the FFT unit 229 is the same as that of the FFT unit 221, so a detailed description thereof is omitted here. The vector can be estimated by the input data symbols defined by the following equation (11)

to represent the signal output from the FFT unit 229.

$\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\overset{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; d</span>}}}<span\; class="notranslate">\; =</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; m</span>}}}_{\mathrm{<span\; class="notranslate">\; t</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; m</span>}}}_{\mathrm{<span\; class="notranslate">\; f</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; e</span>}}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 11</span>}<span\; class="notranslate">\; )</span>$

展开为如下面公式(12)所示。For example, when the equalizer 223 uses a ZF equalizer according to the subcarrier classification channel response of the frequency domain signal as defined in formula (8), and the equalizer 227 performs equalization M _t as defined in formula (10), it is possible to set The input data symbol estimation vector defined by formula (11)

It is expanded as shown in the following formula (12).

$\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\overset{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; d</span>}}}<span\; class="notranslate">\; =</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}{{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}}^{\mathrm{<span\; class="notranslate">\; h</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}{{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}}_{\mathrm{<span\; class="notranslate">\; f</span>}}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; +</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; no</span>}}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; )</span>$

$<span\; class="notranslate">\; =</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}{{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}}^{\mathrm{<span\; class="notranslate">\; h</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}{{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}}_{\mathrm{<span\; class="notranslate">\; f</span>}}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}}_{\mathrm{<span\; class="notranslate">\; t</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; +</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}{{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}}^{\mathrm{<span\; class="notranslate">\; h</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}{{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}}_{\mathrm{<span\; class="notranslate">\; f</span>}}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; no</span>}}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 12</span>}<span\; class="notranslate">\; )</span>$

$<span\; class="notranslate">\; =</span>\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; +</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}{{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}}^{\mathrm{<span\; class="notranslate">\; h</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}{{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}}_{\mathrm{<span\; class="notranslate">\; f</span>}}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; no</span>}}}_{\mathrm{<span\; class="notranslate">\; f</span>}}$

The P/S converter 231 converts the signal from the FFT unit 229 into a serial signal, and then outputs the serial signal including the final input symbol. 1 and 2, the FFH-OFDM communication system performing fast frequency hopping by using all available frequency bands according to the first exemplary embodiment of the present invention has been described above. Hereinafter, an FFH-OFDM communication system that performs fast frequency hopping by using a subset of all available frequency bands according to first and third exemplary embodiments of the present invention will be described.

When the frequency band corresponding to a specific subcarrier is not used for signal transmission but only as a guard band, or when only a subset of all available frequency bands corresponding to a specific subcarrier is allocated to each user for signal transmission, it is necessary to use A subset of all available frequency bands to reflect the second and third embodiments of the invention for fast frequency hopping. The FFH-OFDM communication system can significantly improve system performance by using a dynamic channel allocation (DCA) scheme that dynamically allocates subchannels according to the channel status of users at each time point. Therefore, the second and third embodiments of the present invention propose a scheme for performing fast frequency hopping by using a subset of all available frequency bands. As described in the second and third exemplary embodiments of the present invention, it is assumed that the number of all available frequency bands used in the FFH-OFDM communication system is Q, and the number of subcarriers corresponding to some frequency bands is M (M≤ Q).

Next, differences between the second and third exemplary embodiments of the present invention will be briefly described.

First, in the second exemplary embodiment of the present invention, fast frequency hopping is performed only for M subcarriers, and null data (eg, 0) is inserted into other subcarriers, that is, (Q-M) subcarriers. In this embodiment, the exemplary embodiment of the present invention can be implemented in the same manner as that of the first exemplary embodiment by assuming that frequency bands corresponding to M subcarriers are all available frequency bands.

Next, in the third exemplary embodiment of the present invention, fast frequency hopping is performed by performing fast frequency hopping for all available Q subcarriers including both M subcarriers and (Q-M) subcarriers. Only null data (eg, 0) is inserted into (Q-M) subcarriers and not into the M subcarriers. Specifically, in the third exemplary embodiment of the present invention, null data is inserted into (Q-M) subcarriers in advance. Fast frequency hopping is performed for Q subcarriers. After that, null data is inserted into (Q-M) subcarriers again. Finally, the subcarriers are transmitted. In order to generate the same transmission signal as that of the second embodiment, the third embodiment must satisfy two conditions that will be described in detail below.

A structure of a transmitter of an FFH-OFDM communication system performing a function according to a second exemplary embodiment of the present invention will be described with reference to FIG. 3 .

FIG. 3 is a block diagram showing a structure of a transmitter of an FFH-OFDM communication system performing a function according to a second exemplary embodiment of the present invention.

3, the transmitter includes a serial to parallel (S/P) converter 311, FFH unit 320, Fast Fourier Transform (FFT) unit 331, controller 333, IFFT unit 335, P/S converter 337, protection Space Inserter 339 , D/A Converter 341 and RF Processor 343 . The FFH unit 320 includes an IFFT unit 321 and a linear processor 323 .

First, when there is input data to be transferred, the input data is input to the S/P converter 311 . This data includes actual user data or reference data such as pilots. Since in the second exemplary embodiment of the present invention, fast frequency hopping is performed only for M subcarriers, the S/P converter 311 converts the input data symbols into M parallel symbols, and converts the converted parallel symbols Output to IFFT unit 321. As used here, the parallel signal output from the S/P converter 311 is referred to as d _M represented by the following formula (13).

d _M ＝[d ₁ ...d _M ] ^T ................................(13)

The IFFT unit 321 performs M-point IFFT on the parallel signal d _M output from the S/P converter 311 , and outputs the IFFT-processed signal to the linear processor 323 . The linear processor 323 performs linear processing for the signal from the IFFT unit 321 and then outputs the processed signal to the FFT unit 331 .

Next, the operations of the IFFT unit 321 and the linear processor 323 will be described in more detail.

The transmitter shown in Figure 3 uses only M subcarriers instead of all available frequency bands. Therefore, when performing fast frequency hopping for subcarriers to upload in the transmitter shown in Fig. 3 using only M subcarriers instead of all available frequency bands, at time intervals corresponding to the OFDM sample time period or a multiple of the OFDM sample time period When sending data, the fast frequency hopping matrix is generated in the same manner as the fast frequency hopping matrix G _Q according to the first exemplary embodiment of the present invention. However, in the second exemplary embodiment of the present invention, the newly generated matrix is G _M different from G _Q of the first embodiment. The newly generated fast frequency hopping matrix G _M can be defined by formula (14).

${<span\; class="notranslate">\; [</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; G</span>}}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; ]</span>}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\sqrt{\mathrm{<span\; class="notranslate">\; m</span>}}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; exp</span>}<span\; class="notranslate">\; \{</span>\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="j"\; filenames="H2005800450661E00051.png"\; state="\{\{state\}\}">j</figure-callout></span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\frac{{<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; \&Phi;</span>}<span\; class="notranslate">\; ]</span>}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}}}{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \}</span><span\; class="notranslate">\; ]</span><span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 14</span>}<span\; class="notranslate">\; )</span>$

In formula (14), the fast hopping matrix G _M has a size of M×M. Further, the exemplary embodiment of the present invention is based on the fast frequency hopping pattern, which can prevent the subcarriers used for data transmission from overlapping at predetermined samples, and fast frequency hopping is expressed by the following formula (15) for all fast frequency hopping patterns Matrix G _M .

G _M = Δ _M D _M , Δ _M = G _M D _M ^H ..........(15)

In the formula (15), the values of the elements of the fast frequency hopping matrix G _M and the matrix Δ _M are predetermined according to the fast frequency hopping mode.

Assuming that f _n of the fast frequency hopping pattern is the subcarrier that transmits the data of the first subchannel on the nth sample, when it is generated by using the cyclic fast frequency hopping pattern defined by the following formula (16) defined by the formula (15) When the matrix Δ _M of , it becomes a diagonal matrix.

[Φ] _{n, m} =mod(f _n +m-1, M), m=1, ..., M...........(16)

In this case, the fast hopping matrix G _M is _expressed as a product obtained by multiplying the ordinary IFFT matrix D _M by the matrix ΔM . Thus, the device _for performing fast frequency hopping can be implemented by an IFFT unit and a linear processor capable of multiplying the IFFT matrix by the matrix ΔM . As described herein, example embodiments of the present invention are based on the assumption that fast hopping patterns are examples of cyclic fast hopping patterns. Therefore, _the matrix ΔM can also be defined as a diagonal matrix. Needless to say, this is also true for types that can modify the fast hopping pattern.

As used herein, the signal output from linear processor 323 is referred to as b _M . This signal b _M can be defined by the following formula (17).

b _M = G _M d _M = Δ _M D _M d _M ...................(17)

The FFT unit 331 performs M-point FFT on the signal b _M from the linear processor 323 and then outputs the signal to the controller 333 . The controller 333 receives a signal from the FFT unit 331 , inserts null data (for example, 0) into subcarrier frequency bands other than the M subcarrier frequency bands, and then outputs the signal to the IFFT unit 335 . In this case, the controller 333 acts as a kind of zero inserter (0 inserter). The zero insertion operation of the controller 333 can be expressed by the following formula (18).

${\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span>\left(\begin{array}{c}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}\\ {\mathrm{<span\; class="notranslate">\; 0</span>}}_{\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}}\end{array}\right)<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 18</span>}<span\; class="notranslate">\; )</span>$

ZQ,M is a matrix for representing the operation of the controller 333 of FIG. 3 . As mentioned above, among the output signals of the controller 333, the data transmitted by M subcarriers is the data of M subcarriers that have undergone fast frequency hopping, while the null data transmitted by (Q-M) subcarriers is the data that has never experienced frequency hopping. Fast hopping data.

The IFFT unit 335 receives a signal from the controller 333 , performs Q-point IFFT on the signal, and then outputs the signal to the P/S converter 337 . As used herein, the signal from IFFT unit 335 is referred to as b _Q ⁽¹⁾ . The signal b _Q ⁽¹⁾ can be defined by the following formula (19).

${\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; b</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; Z</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}}}_{\mathrm{<span\; class="notranslate">\; m</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; m</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; d</span>}}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 19</span>}<span\; class="notranslate">\; )</span>$

P/S converter 337, guard interval inserter 339, D/A converter 341, and RF processor 343 perform the same operation as P/S converter 131, guard interval inserter 133, D/A converter shown in FIG. The operations of the RF processor 135 and the RF processor 137 are the same, so their detailed descriptions will be omitted here.

The structure of the transmitter of the FFH-OFDM communication system performing the function according to the second exemplary embodiment of the present invention has been described above with respect to FIG. 3 . Next, a structure of a receiver of an FFH-OFDM communication system performing a function according to a second exemplary embodiment of the present invention will be described with reference to FIG. 4 .

4 is a block diagram showing a structure of a receiver of an FFH-OFDM communication system performing a function according to a second exemplary embodiment of the present invention.

The receiver shown in Fig. 4 includes RF processor 411, D/A converter 413, channel estimator 415, guard interval remover 417, S/P converter 419, FFT unit 421, controller 423, equalizer 425 , IFFT unit 427 , equalizer 429 , FFT unit 431 and P/S converter 433 . RF processor 411, D/A converter 413, guard interval remover 417, and S/P converter 419 of FIG. The operation of the S/P converter 219 is the same, so their detailed description will be omitted here.

As used herein, the signal output from the S/P converter 419 is denoted e _Q . The signal e _Q can be represented by the following formula (20).

e _Q = H _t b _Q ⁽¹⁾ + n _t ...................(20)

The FFT unit 421 performs Q-point FFT on the signal e _Q from the S/P converter 419 , and then outputs the signal to the controller 423 . As used herein, the signal output from the FFT unit 412 is referred to as ef _,Q . The signal e _f,Q may be a frequency domain signal and is defined by the following equation (21).

${\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; e</span>}}}_{\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Q</span>}}<span\; class="notranslate">\; =</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; e</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}<span\; class="notranslate">\; =</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}}_{\mathrm{<span\; class="notranslate">\; t</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; b</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}<span\; class="notranslate">\; +</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; no</span>}}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; twenty\; one</span>}<span\; class="notranslate">\; )</span>$

At the same time, since only M subcarrier signals include data among the Q subcarriers output from the FFT unit 421, the controller 423 eliminates (QM) that contains null data (such as 0) from the signal e _{f, Q} output from the FFT unit 421. subcarrier signals, and only M subcarriers are output to the equalizer 425. In this case, the controller 423 acts as some kind of zero remover (0 remover). The controller 423 removes the 0 inserted by the controller 33 of FIG. 3 .

The zero removal operation of the controller 423 can be expressed by the following formula (22).

Z _{M, Q} = (I _M 0 _{M, QM} )..........(22)

Meanwhile, in order to compensate the signal distortion of the multipath channel, an equalization operation needs to be performed. In an FFH-OFDM communication system, equalization needs to be performed in both the time domain and the frequency domain. Therefore, the FFH-OFDM communication system requires two kinds of equalizers, including a time-domain equalizer for equalizing time-domain signals and a frequency-domain equalizer for equalizing frequency-domain signals.

Therefore, the equalizer 425 equalizes the signals from the controller 423 in the frequency domain, and then outputs them to the IFFT unit 427 . The equalizer 425 compensates for the channel response in the frequency domain.

Further, the IFFT unit 427 performs M-point IFFT on the signal from the equalizer 425 , and then outputs the signal to the equalizer 429 . The operation of the IFFT unit 427 is the same as the operation of the IFFT unit 321 of the transmitter shown in FIG. 3, so a detailed description thereof is omitted here.

The equalizer 429 receives the signal from the IFFT unit 427 , equalizes the signal in the time domain, and then outputs the signal to the FFT unit 431 . As used herein, denote the equalization of a signal in the time domain as M _t,M . The equalization M _t,M in the time domain is defined by the following formula (23).

M _{t, M} = ΔM _H ^{................................} (23)

As represented by formula (23), the equalization M _t,M in the time domain can be represented by the Hermitian conjugate Δ _M ^H of matrix Δ _M defined by formula (15). Therefore, the matrix Δ _M ^H is also a diagonal matrix.

来表示从FFT单元431输出的信号。同时，在公式(24)中，e_f，Q表示从FFT单元431输出并且输入到控制器423的信号，而D _M ^H、M _tM、D _M、M _f，M和Z _M，Q分别表示代表FFT单元431、均衡器429、IFFT单元427、均衡器425和控制器423的矩阵。The FFT unit 431 receives the signal from the equalizer 429 , performs M-point FFT on the signal, and then outputs the signal to the P/S converter 433 . The operation of the FFT unit 431 is the same as that of the FFT unit 331 of FIG. 3 , so a detailed description thereof is omitted here. The vector can be estimated by the input data symbols defined by the following equation (24)

to represent the signal output from the FFT unit 431. Meanwhile, in the formula (24), e _{f, Q} represent the signal output from the FFT unit 431 and input to the controller 423, and D _M ^H , M _tM , D _M , M _{f, M} and Z _{M, Q} represent respectively A matrix representing FFT unit 431 , equalizer 429 , IFFT unit 427 , equalizer 425 and controller 423 .

${\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\overset{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; d</span>}}}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; m</span>}}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; m</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; m</span>}}}_{\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; Z</span>}}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Q</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; e</span>}}}_{\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Q</span>}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; twenty\; four</span>}<span\; class="notranslate">\; )</span>$

The P/S converter 433 converts the signal from the FFT unit 431 into a serial signal, and then outputs the serial signal including the last input signal. The structure of the receiver of the FFH-OFDM communication system performing the function according to the second exemplary embodiment of the present invention has been described above with respect to FIG. 4 . Next, a structure of a transmitter of an FFH-OFDM communication system performing a function according to a third exemplary embodiment of the present invention will be described with reference to FIG. 5 .

5 is a block diagram showing a structure of a transmitter of an FFH-OFDM communication system performing a function according to a third exemplary embodiment of the present invention.

5, the transmitter includes a serial to parallel (S/P) converter 511, a controller 513, an FFH unit 520, an FFT unit 531, a controller 533, an IFFT unit 535, a P/S converter 537, a guard interval interposer 539 , D/A converter 541 and RF processor 543 . The FFH unit 520 includes an IFFT unit 521 and a linear processor 523 .

When there is data to be transferred, the input data is output to the S/P converter 511 . This data includes actual user data or reference data such as pilots. Since in the third exemplary embodiment of the present invention, fast frequency hopping is performed only for M subcarriers, the S/P converter 511 converts the input data symbols into M parallel symbols, and converts the converted parallel symbols output to the controller 513. The controller 513 receives a signal from the S/P converter 511 , inserts null data (for example, 0) into the (Q-M) subcarrier frequency bands except the M subcarrier frequency bands, and then outputs the signal to the IFFT unit 521 . In this case, the controller 513 acts as a kind of zero inserter (0 inserter).

The IFFT unit 521 performs Q-point IFFT on the parallel signal output from the controller 513 and outputs the IFFT-processed signal to the linear processor 523 . The linear processor 523 performs linear processing for the signal from the IFFT unit 521 and then outputs the processed signal to the FFT unit 531 . The operations of the IFFT unit 521 and the linear processor 523 are the same as those of the IFFT unit 121 and the linear processor 123 of FIG. 1 , and thus a detailed description thereof will be omitted here.

The FFT unit 531 performs Q-point FFT on the signal from the FFH unit 520 and then outputs the signal to the controller 533 . As used herein, the signal output from the FFT unit 531 is referred to as b _Q,all . b _Q,all is a signal obtained when M subcarrier signals containing actual data and (QM) subcarrier signals containing null data are spread in the time domain.

The controller 533 receives the signal b _Q,all from the FFT unit 531 , inserts null data (for example, 0) into (QM) subcarrier frequency bands, and then inputs the signal to the IFFT unit 535 . In this case, the controller 533 is used for some kind of zero interpolator (0 interpolator). The zero insertion operation of the controller 533 can be represented by the following formula (25).

${\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}}^{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span>\left(\begin{array}{cc}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}& {\mathrm{<span\; class="notranslate">\; 0</span>}}_{\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}}\\ {\mathrm{<span\; class="notranslate">\; 0</span>}}_{\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}}& {\mathrm{<span\; class="notranslate">\; 0</span>}}_{\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; m</span>}}\end{array}\right)<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 25</span>}<span\; class="notranslate">\; )</span>$

The IFFT unit 535 receives a signal from the controller 533 , performs Q-point IFFT on the signal, and then outputs the signal to the P/S converter 537 . As used herein, the signal output from IFFT unit 535 is referred to as b _Q ⁽²⁾ . The signal b _Q ⁽²⁾ can be defined by the following equation (26). In the following formula (26), d _M represents the data vector input to the controller 513, Z _{Q, M} , D _Q , Δ _Q , D _Q ^H , Z _Q and D _Q represent the representative controller 513 and the IFFT unit 521 respectively , a matrix of linear processor 523 , FFT unit 531 , controller 533 and IFFT unit 525 .

${\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; b</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; Z</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; Z</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; d</span>}}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 26</span>}<span\; class="notranslate">\; )</span>$

As represented by Equation (26), by performing fast frequency hopping after generating a signal with size Q by adding M subcarrier signals conveying real data and (Q-M) subcarrier signals conveying null data, it is possible to fix at the transmitter The number of subcarriers used in each element of the transmitter, thereby achieving a stable hardware configuration of the transmitter, regardless of the number M of subcarriers that actually transmit data.

Meanwhile, the transmission vector b _Q ⁽¹⁾ defined by formula (19) and the transmission vector b _Q ⁽²⁾ defined by formula (26) must satisfy the following two conditions:

(1) The first condition

In order to make the transmission vector b _Q ⁽¹⁾ and the transmission vector b _Q ⁽²⁾ have the same format, it is necessary to set the value of the element of Δ _Q according to the value of the element of Δ _M. The first condition can be expressed by the following formula (27).

Including ${\underset{\&OverBar;}{\mathrm{\&delta;}}}_{Q,f}={\underset{\&OverBar;}{\mathrm{D.}}}_Q^h\mathrm{diag}\left({\underset{\&OverBar;}{\mathrm{\&Delta;}}}_Q\right),{\underset{\&OverBar;}{\mathrm{\&delta;}}}_{Q,f}={\underset{\&OverBar;}{\mathrm{D.}}}_m^h\mathrm{diag}\left({\underset{\&OverBar;}{\mathrm{\&Delta;}}}_m\right)$

以使得第三实施方式具有与第二实施方式的能量总量相同的能量总量。As mentioned above, in the third exemplary embodiment of the present invention, since null data replaces the signal transmitted by (QM) subcarriers, it is necessary to multiply by

So that the third embodiment has the same energy total amount as that of the second embodiment.

(2) The second condition

The second condition is such that the transmission vector always has the same value according to the second and third exemplary embodiments of the present invention. The second condition can be expressed by the following formula (28).

Q≥2M-1..........(28)

P/S converter 537, guard interval inserter 539, D/A converter 541, and RF processor 543 perform the same operations as P/S converter 131, guard interval inserter 133, D/A converter 135, and RF processor 543 of FIG. The operation of the processor 137 is the same, so a detailed description thereof will be omitted here.

The structure of the transmitter of the FFH-OFDM communication system performing the function according to the third exemplary embodiment of the present invention has been described above with respect to FIG. 5 . Next, a structure of a receiver of an FFH-OFDM communication system performing a function according to a third exemplary embodiment of the present invention will be described with reference to FIG. 6 .

6 is a block diagram showing a structure of a receiver of an FFH-OFDM communication system performing a function according to a third exemplary embodiment of the present invention.

The receiver shown in FIG. 6 includes an RF processor 611, a D/A converter 613, a channel estimator 615, a guard interval remover 617, an S/P converter 619, an FFT unit 621, a controller 623, an equalizer 625 , IFFT unit 627 , equalizer 629 , FFT unit 631 , controller 633 and P/S converter 635 . RF processor 611, D/A converter 613, guard interval remover 617, and S/P converter 619 of FIG. The operation of the S/P converter 219 is the same, so their detailed description will be omitted here. Further, the FFT unit 621 performs the same operation as that of the FFT unit 421 of FIG. 4 , so a detailed description thereof will be omitted here.

The signal e _Q input to and the signal e _f,Q output from the FFT unit 621 are the same as the signals e _Q and e _f,Q defined by equations (20) and (21). Further, since the number of subcarriers transmitting actual data in the transmitter of FIG. 5 is M, the M subcarrier signals contain actual data and the (QM) subcarrier signals contain only noise in the frequency domain signal e _f,Q . Therefore, the controller 623 inserts null data (such as 0) into (QM) subcarrier signals in the signal e _{f, Q} output from the FFT unit 621, and then outputs both the M subcarrier signals and the (QM) subcarrier signals to Equalizer 625. In this case, the controller 623 acts as a kind of zero inserter (0 inserter).

The equalizer 625 equalizes the signals from the controller 623 in the frequency domain, and then outputs them to the IFFT unit 627 . The IFFT unit 627 performs Q-point IFFT on the signal from the equalizer 625 , and then outputs the signal to the equalizer 629 . The equalizer 629 receives the signal from the IFFT unit 627 , equalizes the signal in the time domain, and then outputs the signal to the FFT unit 631 . As used herein, the matrix of the equalizer 629 is defined as the Hermitian conjugate of the matrix MQ _,M of the linear processor 523 of the transmitter of FIG. 5 and expressed by equation (29) below.

M _{t, Q} ⁼ ΔQ _H ................................(29)

The FFT unit 631 receives the signal from the equalizer 629 , performs Q-point FFT on the signal, and then outputs the signal to the controller 623 . Of the signals output from the FFT unit 631, the number of subcarriers carrying actual data is M, and the controller 633 selects and outputs only signals corresponding to the number M of estimated data shown by formula (30) below. The controller 633 functions as a kind of selector.

${\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\overset{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; d</span>}}}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; Z</span>}}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Q</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; m</span>}}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Q</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; D.</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; m</span>}}}_{\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Q</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; Z</span>}}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; e</span>}}}_{\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; Q</span>}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 30</span>}<span\; class="notranslate">\; )</span>$

The P/S converter 635 converts the signal from the controller 633 into a serial signal, and then outputs the serial signal including the last input symbol.

As described above, the transmission vectors transmitted by the transmitters according to the second and third exemplary embodiments of the present invention are the same. Therefore, the receiver according to the third example embodiment of the invention can either be used with the transmitter according to the second example embodiment of the invention, or the receiver according to the second example embodiment of the invention can be used with the transmitter according to the third example embodiment of the invention. The transmitter of the embodiment is used together.

The above descriptions regarding the second and third exemplary embodiments of the present invention have only discussed the case where fast frequency hopping is performed for data transmission targeting only one user. However, when all available frequency bands are divided and allocated to a plurality of users in the downlink in an OFDM communication system, the transmitters according to the second and third exemplary embodiments of the present invention may be required for each of the plurality of users and receiver, perform fast frequency hopping using a subset of all available frequency bands. The fourth embodiment of the present invention proposes a scheme for fast frequency hopping in consideration of multiple users (ie, multiple access).

Next, an OFDM system for performing fast frequency hopping in consideration of multiple users (hereinafter referred to as "fast frequency hopping OFDM communication system") will be described with reference to FIG. 7 .

7 is a block diagram showing a structure of a transmitter in a fast frequency hopping OFDM communication system performing a function according to a fourth exemplary embodiment of the present invention.

The transmitter shown in FIG. 7 includes a fast frequency hopping OFDM (FFH-OFDM) processing unit 710, a multiplexer 720, an IFFT unit 730, a P/S converter 740, a guard interval inserter 750, and a D/A converter 760 and RF processor 770. The FFH-OFDM processing unit 710 includes a plurality of FFH-OFDM processors, including a first FFH-OFDM processor 711-1 for processing data targeted at the first user to a Kth FFH processor 711-1 for processing data targeted at the Kth user - OFDM processor 711-K. A second FFH-OFDM processor 711-2 processing data targeted to a second user is shown for example purposes only.

Assume that the numbers of subcarriers to be allocated to the first user to the Kth user are M ₁ to M _{K ,} respectively, and the data d ₁ to be transmitted to the first user to the Kth user is d _K . Input data d ₁ to the first FFH-OFDM processor 711-1, input data d _K to the Kth FFH-OFDM processor 711-K, and input other data to the corresponding FFH-OFDM processing in the same manner device.

The first FFH-OFDM processor 711-1 to the K-th FFH-OFDM processor 711-K perform fast frequency hopping and OFDM modulation in the same manner as described in the second or third exemplary embodiment of the present invention, and then The modulated signals b _M1 to b _MK are output. For example, when the Kth FFH-OFDM processor 711-K performs fast frequency hopping and OFDM modulation in the same manner as in the second exemplary embodiment of the present invention, as in the signal output from the controller 333 of FIG. 3 The number M _K of elements of subcarriers actually used corresponds to b _MK . Conversely, when the K-th FFH-OFDM processor 711-K performs fast frequency hopping and OFDM modulation in the same manner as in the third exemplary embodiment of the present invention, as the signal output from the controller 333 of FIG. 5 The number M _K of elements of subcarriers actually used in corresponds to b _MK .

对应的子载波信号中，然后将该信号输出到IFFT单元730。IFFT单元730对来自复用器720的信号执行Q点IFFT，然后将该信号输出到P/S转换器740。P/S转换器740、保护间隔插入器750、D/A转换器760和RF处理器770执行与图1的/S转换器131、保护间隔插入器133、D/A转换器135和RF处理器137的操作相同的操作，因此这里将省略对其的详细描述。虽然图7的发射机执行用于多个用户的信号的复用，但是接收机还可以解调其自己的信号。因此，根据本发明第二或者第三示例实施方式的接收机也可以使用在本实施方式中而不必使用与图7的发射机对应的分离接收机。Signals b _M1 to b _MK output from the first FFH-OFDM processor 711 - 1 to the K th FFH-OFDM processor 711 -K are input to the multiplexer 720 . Multiplexer 720 inserts 0's into the

The corresponding subcarrier signal is then output to the IFFT unit 730 . The IFFT unit 730 performs Q-point IFFT on the signal from the multiplexer 720 and then outputs the signal to the P/S converter 740 . The P/S converter 740, the guard interval inserter 750, the D/A converter 760, and the RF processor 770 perform the same processing as the /S converter 131, guard interval inserter 133, D/A converter 135, and RF processing of FIG. The operation of the controller 137 is the same, so a detailed description thereof will be omitted here. While the transmitter of FIG. 7 performs multiplexing of signals for multiple users, the receiver can also demodulate its own signals. Therefore, the receiver according to the second or third exemplary embodiment of the present invention can also be used in this embodiment without using a separate receiver corresponding to the transmitter of FIG. 7 .

As described above, exemplary embodiments of the present invention can realize fast frequency hopping in an OFDM communication system and obtain frequency diversity gain within one OFDM symbol time period, thereby improving system performance. Further, exemplary embodiments of the present invention enable fast frequency hopping to be applied not only to all available frequency bands of an OFDM communication system but also to a subset of all available frequency bands, so that the DCA scheme can be used in the OFDM communication system or a guard band can be used Performs fast frequency hopping, thereby improving system performance.

While the invention has been shown and described with reference to particular embodiments thereof, it will be understood by those skilled in the art that changes in form and details may be made without departing from the spirit and scope of the invention as defined by the appended claims. Make various modifications.

Claims (48)

1. An apparatus for signal transmission in a fast frequency hopping-orthogonal frequency division multiplexing (FFH-OFDM) communication system that divides all available frequency bands into a plurality of subcarrier bands and includes a plurality of subchannels each including at least one subcarrier band, the apparatus comprising:

a Fast Frequency Hopping (FFH) unit for allocating input data to a number of subcarriers selected from a plurality of subcarriers, and for performing fast frequency hopping according to a fast frequency hopping pattern to generate an FFH signal;

a Fast Fourier Transform (FFT) unit for performing FFT on the FFH signal;

a controller for inserting null data into remaining subcarriers including subcarriers other than the selected subcarriers;

an Inverse Fast Fourier Transform (IFFT) unit for performing IFFT on both selected subcarriers including input data and remaining subcarriers including inserted null data to generate a first IFFT signal; and

a transmitter for transmitting the first IFFT signal.

2. The apparatus of claim 1, wherein the FFH unit comprises:

a second IFFT unit for allocating input data to the selected subcarriers and then performing IFFT on the selected subcarriers; and

and a linear processor for performing linear processing on the selected subcarriers having undergone the IFFT by the second IFFT unit so that the selected subcarriers have a predetermined gain.

3. The apparatus of claim 2, wherein the FFH unit performs fast frequency hopping according to a fast frequency hopping matrix defined below

<math><mrow><msub><mrow><mo>[</mo><msub><munder><mi>G</mi><mo>&OverBar;</mo></munder><mi>M</mi></msub><mo>]</mo></mrow><mrow><mi>n</mi><mo>,</mo><mi>m</mi></mrow></msub><mo>=</mo><mfrac><mn>1</mn><msqrt><mi>M</mi></msqrt></mfrac><mo>[</mo><mi>exp</mi><mo>{</mo><mi>j</mi><mn>2</mn><mi>&pi;</mi><mrow><mo>(</mo><mi>n</mi><mo>-</mo><mn>1</mn><mo>)</mo></mrow><mo>&CenterDot;</mo><mfrac><msub><mrow><mo>[</mo><mi>&Phi;</mi><mo>]</mo></mrow><mrow><mi>n</mi><mo>,</mo><mi>m</mi></mrow></msub><mi>M</mi></mfrac><mo>}</mo><mo>]</mo><mo>,</mo><mi>m</mi><mo>,</mo><mi>n</mi><mo>=</mo><mn>1</mn><mo>,</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>,</mo><mi>M</mi></mrow></math>

Where n denotes a sample index, m denotes a subchannel index, [ phi ] s]_n，mDenotes a subcarrier on which data of the mth subchannel is transmitted on the nth sample, and M denotes the number of subcarriers selected from among all available Q subcarriers used in the FFH-OFDM communication system.

4. The apparatus of claim 3, wherein the second IFFT unit is according to an IFFT matrix of M-point IFFT unitsD _MIFFT is performed on subcarrier signals corresponding to M subcarriers on a signal-to-carrier basis, the IFFT matrixD _MIs defined as follows

<math><mrow><msub><mrow><mo>[</mo><msub><munder><mi>D</mi><mo>&OverBar;</mo></munder><mi>M</mi></msub><mo>]</mo></mrow><mrow><mi>n</mi><mo>,</mo><mi>m</mi></mrow></msub><mo>=</mo><mfrac><mn>1</mn><msqrt><mi>M</mi></msqrt></mfrac><mo>[</mo><mi>exp</mi><mo>{</mo><mi>j</mi><mn>2</mn><mi>&pi;</mi><mrow><mo>(</mo><mi>n</mi><mo>-</mo><mn>1</mn><mo>)</mo></mrow><mo>&CenterDot;</mo><mfrac><mrow><mi>m</mi><mo>-</mo><mn>1</mn></mrow><mi>M</mi></mfrac><mo>}</mo><mo>]</mo><mo>,</mo><mi>m</mi><mo>,</mo><mi>n</mi><mo>=</mo><mn>1</mn><mo>,</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>,</mo><mi>M</mi><mo>.</mo></mrow></math>

5. The apparatus of claim 4, wherein the linear processor performs linear processing by multiplying the IFFT-processed subcarrier signals in the second IFFT unit by a predetermined diagonal matrix when the fast frequency hopping pattern is a cyclic fast frequency hopping pattern.

6. The apparatus of claim 5, wherein the linear processor is based on a diagonal matrixΔ _MLinear processing is performed with respect to the IFFT-processed subcarrier signals in the second IFFT unit, and the diagonal matrix isΔ _MIs defined as follows

Δ _M＝G _M D _M ^H

Wherein,D _M ^His an IFFT matrixD _MHermite conjugation.

7. The apparatus of claim 6, wherein the recurring fast frequency hopping pattern is a fast frequency hopping pattern defined as

[Ф]_n，m＝mod(f_n+m-1，M)，m＝1，...，M

Wherein f of the fast frequency hopping pattern_nIs the sub-carrier that transmitted the data of the first sub-channel on the nth sample.

8. A method for signal transmission in a fast frequency hopping-orthogonal frequency division multiplexing (FFH-OFDM) communication system that divides all available frequency bands into a plurality of subcarrier bands and includes a plurality of subchannels each including at least one subcarrier band, the method comprising the steps of:

allocating input data to a number of subcarriers selected from a plurality of subcarriers and performing Fast Frequency Hopping (FFH) according to a fast frequency hopping pattern to generate an FFH signal;

performing a Fast Fourier Transform (FFT) on the FFH signal;

inserting null data into remaining subcarriers including subcarriers other than the selected subcarrier;

performing an Inverse Fast Fourier Transform (IFFT) on both the selected subcarriers including the input data and the remaining subcarriers including the inserted null data to generate a first IFFT signal; and

the converted signal having undergone the IFFT by the IFFT unit is transmitted.

9. The method of claim 8, wherein the step of performing FFH comprises the steps of:

(1) allocating input data to the selected subcarriers and then performing IFFT on the selected subcarriers; and

(2) linear processing is performed on the selected subcarriers having undergone the IFFT by the second IFFT unit so that the selected subcarriers have a predetermined gain.

10. The method of claim 9, wherein in the performing FFH, fast frequency hopping is performed according to a fast frequency hopping matrix defined as follows

<math><mrow><msub><mrow><mo>[</mo><msub><munder><mi>G</mi><mo>&OverBar;</mo></munder><mi>M</mi></msub><mo>]</mo></mrow><mrow><mi>n</mi><mo>,</mo><mi>m</mi></mrow></msub><mo>=</mo><mfrac><mn>1</mn><msqrt><mi>M</mi></msqrt></mfrac><mo>[</mo><mi>exp</mi><mo>{</mo><mi>j</mi><mn>2</mn><mi>&pi;</mi><mrow><mo>(</mo><mi>n</mi><mo>-</mo><mn>1</mn><mo>)</mo></mrow><mo>&CenterDot;</mo><mfrac><msub><mrow><mo>[</mo><mi>&Phi;</mi><mo>]</mo></mrow><mrow><mi>n</mi><mo>,</mo><mi>m</mi></mrow></msub><mi>M</mi></mfrac><mo>}</mo><mo>]</mo><mo>,</mo></mrow></math> m，n＝1，...，M

Where n denotes a sample index, m denotes a subchannel index, [ phi ] s]_n，mDenotes a subcarrier on which data of the mth subchannel is transmitted on the nth sample, and M denotes the number of subcarriers selected from among all available Q subcarriers used in the FFH-OFDM communication system.

11. The method as claimed in claim 10, wherein, in step (1), the IFFT matrix according to the M-point IFFT unitD _MIFFT is performed on subcarrier signals corresponding to M subcarriers on a signal-to-carrier basis, the IFFT matrixD _MIs defined as follows

<math><mrow><msub><mrow><mo>[</mo><msub><munder><mi>D</mi><mo>&OverBar;</mo></munder><mi>M</mi></msub><mo>]</mo></mrow><mrow><mi>n</mi><mo>,</mo><mi>m</mi></mrow></msub><mo>=</mo><mfrac><mn>1</mn><msqrt><mi>M</mi></msqrt></mfrac><mo>[</mo><mi>exp</mi><mo>{</mo><mi>j</mi><mn>2</mn><mi>&pi;</mi><mrow><mo>(</mo><mi>n</mi><mo>-</mo><mn>1</mn><mo>)</mo></mrow><mo>&CenterDot;</mo><mfrac><mrow><mi>m</mi><mo>-</mo><mn>1</mn></mrow><mi>M</mi></mfrac><mo>}</mo><mo>]</mo><mo>,</mo></mrow></math> m，n＝1，...，M。

12. The method as claimed in claim 11, wherein, in step (2), the linear processing is performed by multiplying the subcarrier signals IFFT-processed in the second IFFT unit by a predetermined diagonal matrix when the fast frequency hopping pattern is a cyclic fast frequency hopping pattern.

13. The method of claim 12, wherein the recurring fast frequency hopping pattern is a fast frequency hopping pattern defined as

[Ф]_n，m＝mod(f_n+m-1，M)，m＝1，...，M

Wherein f of the fast frequency hopping pattern_nIs the sub-carrier that transmitted the data of the first sub-channel on the nth sample.

14. An apparatus for signal transmission in a fast frequency hopping-orthogonal frequency division multiplexing (FFH-OFDM) communication system that divides all available frequency bands into a plurality of subcarrier bands and includes a plurality of subchannels each including at least one subcarrier band, the apparatus comprising:

a first Fast Fourier Transform (FFT) unit for performing FFT on the received signal;

a controller for separating remaining subcarriers, which include subcarriers other than the selected subcarriers, from the signal FFT-processed in the first FFT unit and then inserting null data into the remaining subcarriers;

a first equalizer for equalizing an output signal of the controller in a frequency domain;

an Inverse Fast Fourier Transform (IFFT) unit for performing IFFT on the equalized signal of the first equalizer according to a fast frequency hopping matrix applied by the transmission device;

a second equalizer for equalizing the IFFT-processed signal in the time domain; and

a second Fast Fourier Transform (FFT) unit for performing FFT on the signal equalized in the time domain.

15. The apparatus of claim 14, wherein the fast frequency hopping matrix is defined as follows

<math><mrow><msub><mrow><mo>[</mo><msub><munder><mi>G</mi><mo>&OverBar;</mo></munder><mi>M</mi></msub><mo>]</mo></mrow><mrow><mi>n</mi><mo>,</mo><mi>m</mi></mrow></msub><mo>=</mo><mfrac><mn>1</mn><msqrt><mi>M</mi></msqrt></mfrac><mo>[</mo><mi>exp</mi><mo>{</mo><mi>j</mi><mn>2</mn><mi>&pi;</mi><mrow><mo>(</mo><mi>n</mi><mo>-</mo><mn>1</mn><mo>)</mo></mrow><mo>&CenterDot;</mo><mfrac><msub><mrow><mo>[</mo><mi>&Phi;</mi><mo>]</mo></mrow><mrow><mi>n</mi><mo>,</mo><mi>m</mi></mrow></msub><mi>M</mi></mfrac><mo>}</mo><mo>]</mo><mo>,</mo></mrow></math> m，n＝1，...，M

Wherein,G _Mdenotes a fast hopping matrix, n denotes a sample index, m denotes a subchannel index, [ phi ]]_n，mDenotes a subcarrier on which data of the mth subchannel is transmitted on the nth sample, and M denotes the number of subcarriers selected from among all available Q subcarriers used in the FFH-OFDM communication system.

16. The apparatus as claimed in claim 15, wherein the second equalizer performs equalization by multiplying the IFFT-processed subcarrier signals by hermitian conjugates of a predetermined diagonal matrix when the fast frequency hopping pattern is a cyclic fast frequency hopping pattern.

17. The apparatus of claim 16, wherein the recurring fast frequency hopping pattern is a fast frequency hopping pattern defined as

[Ф]_n，m＝mod(f_n+m-1，M)，m＝1，...，M

Wherein f of the fast frequency hopping pattern_nIs the sub-carrier that transmitted the data of the first sub-channel on the nth sample.

18. A method for signal transmission in a fast frequency hopping-orthogonal frequency division multiplexing (FFH-OFDM) communication system that divides all available frequency bands into a plurality of sub-bands and includes a plurality of sub-channels each including at least one sub-carrier band, the method comprising the steps of:

(1) performing a Fast Fourier Transform (FFT) on the received signal;

(2) separating remaining subcarriers, which include subcarriers other than a plurality of selected subcarriers through which the transmitting apparatus transmits data, from the FFT-processed signal in the first FFT unit, and then inserting null data into the remaining subcarriers;

(3) equalizing the signal generated in step (2) in the frequency domain;

(4) performing an Inverse Fast Fourier Transform (IFFT) on the equalized signal in the frequency domain according to the fast frequency hopping matrix;

(5) equalizing the IFFT-processed signals in the time domain; and

(6) a Fast Fourier Transform (FFT) is performed on the equalized signal in the time domain.

19. The method of claim 18, the fast frequency hopping matrix is defined as follows

<math><mrow><msub><mrow><mo>[</mo><msub><munder><mi>G</mi><mo>&OverBar;</mo></munder><mi>M</mi></msub><mo>]</mo></mrow><mrow><mi>n</mi><mo>,</mo><mi>m</mi></mrow></msub><mo>=</mo><mfrac><mn>1</mn><msqrt><mi>M</mi></msqrt></mfrac><mo>[</mo><mi>exp</mi><mo>{</mo><mi>j</mi><mn>2</mn><mi>&pi;</mi><mrow><mo>(</mo><mi>n</mi><mo>-</mo><mn>1</mn><mo>)</mo></mrow><mo>&CenterDot;</mo><mfrac><msub><mrow><mo>[</mo><mi>&Phi;</mi><mo>]</mo></mrow><mrow><mi>n</mi><mo>,</mo><mi>m</mi></mrow></msub><mi>M</mi></mfrac><mo>}</mo><mo>]</mo><mo>,</mo></mrow></math> m，n＝1，...，M

Wherein,G _Mdenotes a fast hopping matrix, n denotes a sample index, m denotes a subchannel index, [ phi ]]_n，mDenotes a subcarrier on which data of the mth subchannel is transmitted on the nth sample, and M denotes the number of subcarriers selected from among all available Q subcarriers used in the FFH-OFDM communication system.

20. The method as claimed in claim 19, wherein, in step (5), the equalization is performed by multiplying the IFFT-processed subcarrier signals by hermitian conjugates of a predetermined diagonal matrix when the fast frequency hopping pattern is a cyclic fast frequency hopping pattern.

21. The apparatus of claim 20, wherein the recurring fast frequency hopping pattern is a fast frequency hopping pattern defined as

[Ф]_n，m＝mod(f_n+m-1，M)，m＝1，...，M

Wherein f of the fast frequency hopping pattern_nIs the sub-carrier that transmitted the data of the first sub-channel on the nth sample.

22. An apparatus for signal transmission in a fast frequency hopping-orthogonal frequency division multiplexing (FFH-OFDM) communication system that divides all available frequency bands into a plurality of subcarrier bands and includes a plurality of subchannels each including at least one subcarrier band, the apparatus comprising:

a first controller for inserting null data into remaining subcarriers including subcarriers other than a number of selected subcarriers through which input data is carried among all available subcarriers;

a Fast Frequency Hopping (FFH) unit for allocating input data to a number of selected sub-carriers and for performing fast frequency hopping according to a fast frequency hopping pattern to generate an FFH signal;

a Fast Fourier Transform (FFT) unit for performing FFT on the FFH signal;

a second controller for inserting null data into the remaining subcarriers;

a first Inverse Fast Fourier Transform (IFFT) unit for performing IFFT on both selected subcarriers including input data and remaining subcarriers including inserted null data to generate a first IFFT signal; and

a transmitter for transmitting the first IFFT signal.

23. The apparatus of claim 22, wherein the FFH unit comprises:

a second IFFT unit for performing IFFT on the signal output from the first controller; and

and a linear processor for performing linear processing of the subcarriers that have been subjected to the IFFT processing by the second IFFT unit so that the subcarriers have a predetermined gain.

24. The apparatus of claim 23, wherein the FFH unit performs fast frequency hopping according to a fast frequency hopping matrix defined as follows

<math><mrow><msub><mrow><mo>[</mo><msub><munder><mi>G</mi><mo>&OverBar;</mo></munder><mi>Q</mi></msub><mo>]</mo></mrow><mrow><mi>n</mi><mo>,</mo><mi>m</mi></mrow></msub><mo>=</mo><mfrac><mn>1</mn><msqrt><mi>Q</mi></msqrt></mfrac><mo>[</mo><mi>exp</mi><mo>{</mo><mi>j</mi><mn>2</mn><mi>&pi;</mi><mrow><mo>(</mo><mi>n</mi><mo>-</mo><mn>1</mn><mo>)</mo></mrow><mo>&CenterDot;</mo><mfrac><msub><mrow><mo>[</mo><mi>&Phi;</mi><mo>]</mo></mrow><mrow><mi>n</mi><mo>,</mo><mi>m</mi></mrow></msub><mi>Q</mi></mfrac><mo>}</mo><mo>]</mo><mo>,</mo></mrow></math> m，n＝1，...，Q

Wherein n represents the sameThis index, m denotes the subchannel index, [ phi ]]_n，mDenotes a subcarrier on which data of the mth subchannel is transmitted at the nth sample, and Q denotes the number of all available subcarriers used in the FFH-OFDM communication system.

25. The apparatus of claim 24, wherein the second IFFT unit is according to an IFFT matrix of Q-point IFFT unitsD _QPerforming IFFT on subcarrier signals corresponding to M subcarriers on a signal-to-carrier basis, the Q-point IFFT matrixD _QIs defined as follows

<math><mrow><msub><mrow><mo>[</mo><msub><munder><mi>D</mi><mo>&OverBar;</mo></munder><mi>Q</mi></msub><mo>]</mo></mrow><mrow><mi>n</mi><mo>,</mo><mi>m</mi></mrow></msub><mo>=</mo><mfrac><mn>1</mn><msqrt><mi>Q</mi></msqrt></mfrac><mo>[</mo><mi>exp</mi><mo>{</mo><mi>j</mi><mn>2</mn><mi>&pi;</mi><mrow><mo>(</mo><mi>n</mi><mo>-</mo><mn>1</mn><mo>)</mo></mrow><mo>&CenterDot;</mo><mfrac><mrow><mi>m</mi><mo>-</mo><mn>1</mn></mrow><mi>Q</mi></mfrac><mo>}</mo><mo>]</mo><mo>,</mo></mrow></math> m，n＝1，...，Q。

26. The apparatus of claim 25, wherein the linear processor performs linear processing by multiplying the IFFT-processed subcarrier signals in the second IFFT unit by a predetermined diagonal matrix when the fast frequency hopping pattern is a cyclic fast frequency hopping pattern.

27. The apparatus of claim 26, wherein the recurring fast frequency hopping pattern is a fast frequency hopping pattern defined as

[Ф]_n，m＝mod(f_n+m-1，M)，m＝1，...，M

Wherein f of the fast frequency hopping pattern_nIs the sub-carrier that transmitted the data of the first sub-channel on the nth sample.

28. The apparatus of claim 27, wherein the diagonal matrix satisfies

And

therein is provided with <math><mrow><msub><munder><mi>&delta;</mi><mo>&OverBar;</mo></munder><mrow><mi>Q</mi><mo>,</mo><mi>F</mi></mrow></msub><mo>=</mo><msubsup><munder><mi>D</mi><mo>&OverBar;</mo></munder><mi>Q</mi><mi>H</mi></msubsup><mi>diag</mi><mrow><mo>(</mo><msub><munder><mi>&Delta;</mi><mo>&OverBar;</mo></munder><mi>Q</mi></msub><mo>)</mo></mrow><mo>,</mo><msub><munder><mi>&delta;</mi><mo>&OverBar;</mo></munder><mrow><mi>Q</mi><mo>,</mo><mi>F</mi></mrow></msub><mo>=</mo><msubsup><munder><mi>D</mi><mo>&OverBar;</mo></munder><mi>M</mi><mi>H</mi></msubsup><mi>diag</mi><mrow><mo>(</mo><msub><munder><mi>&Delta;</mi><mo>&OverBar;</mo></munder><mi>M</mi></msub><mo>)</mo></mrow></mrow></math>

Q≥2M-1，

Where M represents the number of subcarriers selected,Δ _Qrepresenting a diagonal matrix, andΔ _Mrepresents a diagonal matrix when fast frequency hopping is performed without inserting null data into the remaining subcarriers.

29. A method for signal transmission in a fast frequency hopping-orthogonal frequency division multiplexing (FFH-OFDM) communication system that divides all available frequency bands into a plurality of subcarrier bands and includes a plurality of subchannels each including at least one subcarrier band, the method comprising the steps of:

(1) inserting null data into remaining subcarriers including subcarriers other than a number of selected subcarriers through which input data is carried among all available subcarriers;

(2) allocating input data to a plurality of selected sub-carriers and then performing fast frequency hopping according to a fast frequency hopping pattern to generate an FFH signal;

(3) performing a Fast Fourier Transform (FFT) on the FFH signal;

(4) inserting null data into the remaining subcarriers;

(5) performing an inverse fast fourier transform on both the selected subcarriers including the input data and the remaining subcarriers including the inserted null data to generate IFFT signals; and

(6) the IFFT signals are transmitted.

30. The method as claimed in claim 29, wherein the step (2) comprises the steps of:

(7) performing IFFT on the signal generated in step (1); and

(8) linear processing of the subcarriers having undergone the IFFT processing of step (7) is performed so that the subcarriers have a predetermined gain.

31. The method as claimed in claim 30, wherein, in step (2), the fast frequency hopping is performed according to a fast frequency hopping matrix defined as follows

<math><mrow><msub><mrow><mo>[</mo><msub><munder><mi>G</mi><mo>&OverBar;</mo></munder><mi>Q</mi></msub><mo>]</mo></mrow><mrow><mi>n</mi><mo>,</mo><mi>m</mi></mrow></msub><mo>=</mo><mfrac><mn>1</mn><msqrt><mi>Q</mi></msqrt></mfrac><mo>[</mo><mi>exp</mi><mo>{</mo><mi>j</mi><mn>2</mn><mi>&pi;</mi><mrow><mo>(</mo><mi>n</mi><mo>-</mo><mn>1</mn><mo>)</mo></mrow><mo>&CenterDot;</mo><mfrac><msub><mrow><mo>[</mo><mi>&Phi;</mi><mo>]</mo></mrow><mrow><mi>n</mi><mo>,</mo><mi>m</mi></mrow></msub><mi>Q</mi></mfrac><mo>}</mo><mo>]</mo><mo>,</mo></mrow></math> m，n＝1，...，Q

Where n denotes a sample index, m denotes a subchannel index, [ phi ] s]_n，mDenotes a sub-carrier transmitting data of the mth sub-channel on the nth sample, and Q denotes a symbol in the FFH-OFDM communication systemThe number of all available subcarriers used in the system.

32. The method as claimed in claim 31, wherein, in step (7), the IFFT matrix according to the Q-point IFFT unitD _QPerforming IFFT on subcarrier signals corresponding to M subcarriers on a signal-to-carrier basis, the Q-point IFFT matrixD _QIs defined as follows

<math><mrow><msub><mrow><mo>[</mo><msub><munder><mi>D</mi><mo>&OverBar;</mo></munder><mi>Q</mi></msub><mo>]</mo></mrow><mrow><mi>n</mi><mo>,</mo><mi>m</mi></mrow></msub><mo>=</mo><mfrac><mn>1</mn><msqrt><mi>Q</mi></msqrt></mfrac><mo>[</mo><mi>exp</mi><mo>{</mo><mi>j</mi><mn>2</mn><mi>&pi;</mi><mrow><mo>(</mo><mi>n</mi><mo>-</mo><mn>1</mn><mo>)</mo></mrow><mo>&CenterDot;</mo><mfrac><mrow><mi>m</mi><mo>-</mo><mn>1</mn></mrow><mi>Q</mi></mfrac><mo>}</mo><mo>]</mo><mo>,</mo></mrow></math> m，n＝1，...，Q。

33. The method as claimed in claim 32, wherein, in step (8), the linear processing is performed by multiplying the subcarrier signals IFFT-processed in the second IFFT unit by a predetermined diagonal matrix when the fast frequency hopping pattern is a cyclic fast frequency hopping pattern.

34. The method of claim 33, wherein the recurring fast frequency hopping pattern is a fast frequency hopping pattern defined as

[Ф]_n，m＝mod(f_n+m-1，M)，m＝1，...，M

Wherein f of the fast frequency hopping pattern_nIs the sub-carrier that transmitted the data of the first sub-channel on the nth sample.

35. The method of claim 34, wherein the diagonal matrix satisfies

And

therein is provided with <math><mrow><msub><munder><mi>&delta;</mi><mo>&OverBar;</mo></munder><mrow><mi>Q</mi><mo>,</mo><mi>F</mi></mrow></msub><mo>=</mo><msubsup><munder><mi>D</mi><mo>&OverBar;</mo></munder><mi>Q</mi><mi>H</mi></msubsup><mi>diag</mi><mrow><mo>(</mo><msub><munder><mi>&Delta;</mi><mo>&OverBar;</mo></munder><mi>Q</mi></msub><mo>)</mo></mrow><mo>,</mo><msub><munder><mi>&delta;</mi><mo>&OverBar;</mo></munder><mrow><mi>Q</mi><mo>,</mo><mi>F</mi></mrow></msub><mo>=</mo><msubsup><munder><mi>D</mi><mo>&OverBar;</mo></munder><mi>M</mi><mi>H</mi></msubsup><mi>diag</mi><mrow><mo>(</mo><msub><munder><mi>&Delta;</mi><mo>&OverBar;</mo></munder><mi>M</mi></msub><mo>)</mo></mrow></mrow></math>

Q≥2M-1，

Where M denotes the number of predetermined sub-carriers,Δ _Qrepresenting a diagonal matrix, andΔ _Mrepresents a diagonal matrix when fast frequency hopping is performed without inserting null data into the remaining subcarriers at step (1).

36. An apparatus for signal transmission in a fast frequency hopping-orthogonal frequency division multiplexing (FFH-OFDM) communication system that divides all available frequency bands into a plurality of subcarrier bands and includes a plurality of subchannels each including at least one subcarrier band, the apparatus comprising:

a first Fast Fourier Transform (FFT) unit for performing FFT on the received signal;

a first controller for separating remaining subcarriers, which include subcarriers other than a plurality of selected subcarriers through which the transmitting apparatus transmits data, from the signal FFT-processed in the first FFT unit, and then inserting null data into the remaining subcarriers;

a first equalizer for equalizing an output signal of the controller in a frequency domain;

an Inverse Fast Fourier Transform (IFFT) unit for performing IFFT on the signal equalized by the first equalizer according to a fast frequency hopping matrix applied by the transmission device;

a second equalizer for equalizing the signal subjected to the IFFT in the time domain;

a second fast Fourier transform (IFFT) unit for performing FFT on the equalized signal in the time domain; and

a second controller for separating the remaining subcarriers from the signal FFT-processed in the second FFT unit and then inserting null data into the remaining subcarriers.

37. The apparatus of claim 36, wherein the fast frequency hopping matrix is defined as follows

<math><mrow><msub><mrow><mo>[</mo><msub><munder><mi>G</mi><mo>&OverBar;</mo></munder><mi>Q</mi></msub><mo>]</mo></mrow><mrow><mi>n</mi><mo>,</mo><mi>m</mi></mrow></msub><mo>=</mo><mfrac><mn>1</mn><msqrt><mi>Q</mi></msqrt></mfrac><mo>[</mo><mi>exp</mi><mo>{</mo><mi>j</mi><mn>2</mn><mi>&pi;</mi><mrow><mo>(</mo><mi>n</mi><mo>-</mo><mn>1</mn><mo>)</mo></mrow><mo>&CenterDot;</mo><mfrac><msub><mrow><mo>[</mo><mi>&Phi;</mi><mo>]</mo></mrow><mrow><mi>n</mi><mo>,</mo><mi>m</mi></mrow></msub><mi>Q</mi></mfrac><mo>}</mo><mo>]</mo><mo>,</mo></mrow></math> m，n＝1，...，Q

Wherein,G _Mdenotes a fast hopping matrix, n denotes a sample index, m denotes a subchannel index, [ phi ]]_n，mDenotes a subcarrier on which data of the mth subchannel is transmitted at the nth sample, and Q denotes the number of all available subcarriers used in the FFH-OFDM communication system.

38. The apparatus as claimed in claim 37, wherein the second equalizer performs equalization by multiplying the IFFT-processed subcarrier signals by hermitian conjugates of a predetermined diagonal matrix when the fast frequency hopping pattern is a cyclic fast frequency hopping pattern.

39. The apparatus of claim 38, wherein the recurring fast frequency hopping pattern is a fast frequency hopping pattern defined as

[Ф]_n，m＝mod(f_n+m-1，M)，m＝1，...，M

Wherein f of the fast frequency hopping pattern_nIs the sub-carrier that transmitted the data of the first sub-channel on the nth sample.

40. The apparatus of claim 39, wherein the diagonal matrix satisfies

And

therein is provided with <math><mrow><msub><munder><mi>&delta;</mi><mo>&OverBar;</mo></munder><mrow><mi>Q</mi><mo>,</mo><mi>F</mi></mrow></msub><mo>=</mo><msubsup><munder><mi>D</mi><mo>&OverBar;</mo></munder><mi>Q</mi><mi>H</mi></msubsup><mi>diag</mi><mrow><mo>(</mo><msub><munder><mi>&Delta;</mi><mo>&OverBar;</mo></munder><mi>Q</mi></msub><mo>)</mo></mrow><mo>,</mo><msub><munder><mi>&delta;</mi><mo>&OverBar;</mo></munder><mrow><mi>Q</mi><mo>,</mo><mi>F</mi></mrow></msub><mo>=</mo><msubsup><munder><mi>D</mi><mo>&OverBar;</mo></munder><mi>M</mi><mi>H</mi></msubsup><mi>diag</mi><mrow><mo>(</mo><msub><munder><mi>&Delta;</mi><mo>&OverBar;</mo></munder><mi>M</mi></msub><mo>)</mo></mrow></mrow></math>

Q≥2M-1，

Where M denotes the number of predetermined sub-carriers,Δ _Qrepresenting a diagonal matrix, andΔ _Mindicating that null data is not inserted into the remaining sub-blocks when fast frequency hopping is performedA diagonal matrix of time in the carrier.

41. A method for signal transmission in a fast frequency hopping-orthogonal frequency division multiplexing (FFH-OFDM) communication system that divides all available frequency bands into a plurality of subcarrier bands and includes a plurality of subchannels each including at least one subcarrier band, the method comprising the steps of:

(1) performing a Fast Fourier Transform (FFT) on the received signal;

(2) separating remaining subcarriers, which include subcarriers other than a plurality of selected subcarriers through which the transmitting apparatus transmits data, from the signal subjected to the FFT processing in the first FFT unit, and then inserting null data into the remaining subcarriers;

(3) equalizing the signal generated in step (2);

(4) performing an Inverse Fast Fourier Transform (IFFT) on the equalized signal in the frequency domain according to the fast frequency hopping matrix;

(5) equalizing the IFFT-passed signals in the time domain;

(6) performing a Fast Fourier Transform (FFT) on the equalized signal in the time domain; and

(7) remaining subcarriers are separated from the signal FFT-processed in the second FFT unit and null data is then inserted into the remaining subcarriers.

42. The method of claim 41, wherein the fast hopping matrix is defined as follows

<math><mrow><msub><mrow><mo>[</mo><msub><munder><mi>G</mi><mo>&OverBar;</mo></munder><mi>Q</mi></msub><mo>]</mo></mrow><mrow><mi>n</mi><mo>,</mo><mi>m</mi></mrow></msub><mo>=</mo><mfrac><mn>1</mn><msqrt><mi>Q</mi></msqrt></mfrac><mo>[</mo><mi>exp</mi><mo>{</mo><mi>j</mi><mn>2</mn><mi>&pi;</mi><mrow><mo>(</mo><mi>n</mi><mo>-</mo><mn>1</mn><mo>)</mo></mrow><mo>&CenterDot;</mo><mfrac><msub><mrow><mo>[</mo><mi>&Phi;</mi><mo>]</mo></mrow><mrow><mi>n</mi><mo>,</mo><mi>m</mi></mrow></msub><mi>Q</mi></mfrac><mo>}</mo><mo>]</mo><mo>,</mo></mrow></math> m，n＝1，...，Q

Wherein,G _Mdenotes a fast hopping matrix, n denotes a sample index, m denotes a subchannel index, [ phi ]]_n，mDenotes a subcarrier on which data of the mth subchannel is transmitted at the nth sample, and Q denotes the number of all available subcarriers used in the FFH-OFDM communication system.

43. The method as claimed in claim 42, wherein, in step (5), when the fast frequency hopping pattern is a cyclic fast frequency hopping pattern, the equalization is performed by multiplying the IFFT-processed subcarrier signals by hermitian conjugates of a predetermined diagonal matrix.

44. The method of claim 43, wherein the recurring fast frequency hopping pattern is a fast frequency hopping pattern defined as

[Ф]_n，m＝mod(f_n+m-1，M)，m＝1，...，M

Wherein f of the fast frequency hopping pattern_nIs the sub-carrier that transmitted the data of the first sub-channel on the nth sample.

45. The method of claim 44, wherein the diagonal matrix satisfies

And

therein is provided with <math><mrow><msub><munder><mi>&delta;</mi><mo>&OverBar;</mo></munder><mrow><mi>Q</mi><mo>,</mo><mi>F</mi></mrow></msub><mo>=</mo><msubsup><munder><mi>D</mi><mo>&OverBar;</mo></munder><mi>Q</mi><mi>H</mi></msubsup><mi>diag</mi><mrow><mo>(</mo><msub><munder><mi>&Delta;</mi><mo>&OverBar;</mo></munder><mi>Q</mi></msub><mo>)</mo></mrow><mo>,</mo><msub><munder><mi>&delta;</mi><mo>&OverBar;</mo></munder><mrow><mi>Q</mi><mo>,</mo><mi>F</mi></mrow></msub><mo>=</mo><msubsup><munder><mi>D</mi><mo>&OverBar;</mo></munder><mi>M</mi><mi>H</mi></msubsup><mi>diag</mi><mrow><mo>(</mo><msub><munder><mi>&Delta;</mi><mo>&OverBar;</mo></munder><mi>M</mi></msub><mo>)</mo></mrow></mrow></math>

Q≥2M-1，

Where M denotes the number of predetermined sub-carriers,Δ _Qrepresenting a diagonal matrix, andΔ _Mrepresents a diagonal matrix when fast frequency hopping is performed without inserting null data into the remaining subcarriers in step (1).

46. An apparatus for signal transmission in a fast frequency hopping-orthogonal frequency division multiplexing (FFH-OFDM) communication system that divides all available frequency bands into a plurality of subcarrier bands and includes a plurality of subchannels each including at least one subcarrier band, the apparatus comprising:

a fast frequency hopping-OFDM (FFH-OFDM) processing unit for performing fast frequency hopping for a signal to be transmitted by each user and converting the signal into an OFDM signal, the FFH-OFDM processing unit including a plurality of processors each of which allocates input data to a number of subcarriers selected from a plurality of subcarriers and for performing fast frequency hopping according to a fast frequency hopping pattern to generate an FFH-OFDM signal;

a multiplexer for multiplexing the FFH-OFDM signal;

an Inverse Fast Fourier Transform (IFFT) unit for performing IFFT on the multiplexed signal; and

and a transmitter for transmitting the signal through the IFFT.

47. The device of claim 46, wherein each of the processors comprises:

a second IFFT unit for allocating input data to the selected subcarriers and then performing IFFT on the subcarriers; and

a linear processor for performing linear processing of the selected subcarriers that have been subjected to the IFFT processing by the second IFFT unit so that the selected subcarriers have a predetermined gain.

48. The device of claim 46, wherein each of the processors comprises:

a first controller for inserting null data into remaining subcarriers including subcarriers other than a number of selected subcarriers through which input data is carried among all available subcarriers;

a second IFFT unit for performing IFFT on the signal output from the first controller; and

and a linear processor for performing linear processing of the sub-carriers having undergone the IFFT by the second IFFT unit so that the sub-carriers have a predetermined gain.

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