JPH09261129A - Spread spectrum communication equipment - Google Patents

Abstract

(57) Abstract: A spread spectrum communication device capable of easily synchronizing spread codes. SOLUTION: One bit of transmission data 1 is encoded by a convolutional encoder 2 into a K-bit codeword. The interleave circuit 3 rearranges the K-bit codeword in time order and outputs it to the mapping circuit 4. Mapping circuit 4
Then, one spreading code is determined from the spreading code sequences of 2 K power types, and the spreading code generation circuit 5 generates the one spreading code determined by the mapping circuit 4. On the other hand, the pilot signal generation circuit 6 uses the K of 2 used for data transmission.
A pilot signal spread by a spreading code different from the power spreading code is generated. The signal spread by the spreading code of 1 and the pilot signal are combined, converted into a signal for wireless transmission, and transmitted from the transmitting antenna 9. The synchronization circuit 12 synchronizes the spreading code by performing correlation detection with the spreading code used for the pilot signal constantly transmitted by the transmitter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spread spectrum communication apparatus used for digital radio communication such as a car phone and a mobile phone, and more particularly to a spread spectrum communication apparatus capable of easily synchronizing spread codes.

[0002]

2. Description of the Related Art A spread spectrum (SS) communication method is a method of spreading information in a band sufficiently wider than the minimum required bandwidth when transmitting information, and it provides confidentiality and confidentiality. It is known that this is a communication method that is excellent in communication and interference. The direct sequence SS (DS-SS) method is a spread spectrum communication method in which an information signal is directly multiplied by a spreading code in spreading.

In a cellular radio communication system such as a car phone and a mobile phone, FDMA is used as a multiple access technique when a plurality of stations simultaneously communicate in the same frequency band.
(Frequency Division Multiple Access: Frequency Division Multiple Access) method, TDMA (Time Division Multiple Access:
Time division multiple access (CDMA) is known, but CDMA (Code Division Multiple Acces
The s: code division multiple access method is a method that can achieve higher frequency utilization efficiency and can accommodate a larger number of users compared to these technologies.

Paper "Proposal of parallel combination SS communication system"
(Zhu, Sasaki, Marubayashi, IEICE Transactions B-II Vol.
J74-B-II No.5) proposes a spread spectrum communication method by a parallel combination method as a method for further improving the frequency utilization efficiency.

In the parallel combination spread spectrum communication system, K bits of information bits are regarded as one data symbol, and n is made to correspond to the 2 K power states of this data symbol.
One of n combinations of nCr that selects r from the spreading code series of the type is selected, and the selected spreading code of the r types is multiplied by +1 or -1 (the phase is 0 degree or 18 degrees).
This is a method of performing communication by the added signal (rotated by 0 degree).

Similarly, there is an M array spread spectrum system as a system for communicating information depending on the type of spread code. In the spread spectrum method of the M array method, K bits of information bits are taken as one data symbol, and one spread code is selected from 2K kinds of spread code sequences corresponding to 2K power states of this data symbol. Is a method in which communication is performed using a signal that has been spread spectrum with the spread code selected.

This corresponds to the case where n is equal to 2 to the Kth power and r is 1 in the parallel combinatory spread spectrum system, and phase rotation control is not performed. The M-array method used in the uplink of IS-95, which is one of the North American standards for digital mobile communication, is an example when K is 6.

FIG. 3 shows the configuration of a parallel combination spread spectrum communication device in a conventional example. The transmission data 30 is divided into K bits and is input to the spread code mapping circuit 31. The spread code mapping circuit 31 determines the combination of selecting r from the n kinds of spread code sequences and the polarities of the spread codes according to the input K-bit states of 2 to the Kth power, and generates the spread code. circuit
Enter 32.

The spread code generation circuit 32 generates r spread codes determined by the spread code mapping circuit 31. The r spread codes generated by the spread code generation circuit 32 are added by the adder 33, converted by the modulator 34 into a signal for wireless transmission, and transmitted from the transmission antenna 35.

The transmitted signal is received by the receiving antenna 36 at the receiver.
Is received, is converted into a baseband signal by the demodulator 37, and is input to the correlator 38. The correlator 38 performs correlation detection for all n types of spreading codes, and determines the types and polarities of the r spreading codes used for transmission in the transmitter. In the information bit demapping circuit 39, K-bit received data 40 is obtained from the r types of spreading codes determined by the correlator 38 and their polarities.

In the case of the M array spread spectrum system, the operation is partly different with the same configuration. The transmission data 30 is divided into K bits and is input to the spread code mapping circuit 31. In the spread code mapping circuit 31, one spread code is selected from the 2 K power type spread code sequences according to the input K-bit 2 K power states, and the result is sent to the spread code generation circuit 32. input.

The spread code generation circuit 32 generates one spread code determined by the spread code mapping circuit 31. Since there is only one type of spreading code, the addition process in the adder 33 is unnecessary and is input to the modulator 34 as it is. The signal input to the modulator 34 is converted into a signal for wireless transmission and transmitted from the transmission antenna 35.

The transmitted signal is received by the receiving antenna 36 at the receiver.
Is received, is converted into a baseband signal by the demodulator 37, and is input to the correlator 38. The correlator 38 performs correlation detection on all spreading codes of the 2 Kth power type, and determines the type of one spreading code used for transmission in the transmitter. In the information bit demapping circuit 39, the correlator 38
The K-bit received data 40 is obtained according to the type of the spreading code determined in (1).

[0014]

However, in the above-mentioned conventional M-array spread spectrum communication apparatus, since the spread code to be transmitted is constantly changing, it is difficult for the receiver to synchronize the spread code with the received signal. There was a problem that there is.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide an excellent spread spectrum communication device capable of easily synchronizing spread codes.

[0016]

In order to solve the above problems, the present invention provides a pilot channel spread with a spreading code different from the 2 K power spreading codes used for data transmission in a transmitter. By transmitting and receiving the pilot channel in the receiver, the received signal is synchronized.

Further, in order to solve the above-mentioned problems, the present invention uses 2 Ks which are used for transmission of data symbols in some specific symbols in a transmission frame in a transmitter.
A pilot symbol spread by a specific one spreading code of the power-type spreading code sequences or by a spreading code different from the 2 K-power-type spreading code sequence is transmitted, and the pilot symbol is received by a receiver. , The transmission timing is regenerated and synchronized, and the phase rotation of several pilot symbols in the transmission frame or the phase rotation of multiple pilot symbols over multiple transmission frames is changed to the phase rotation by the transmission path of preceding and following data symbols. The structure is estimated.

As described above, an excellent digital mobile communication device capable of easily synchronizing the spread codes can be obtained.

[0019]

DETAILED DESCRIPTION OF THE INVENTION Claims 1 and 2 of the present invention
According to the invention described in (1), 1 bit is selected from 2 K spreading types of spreading code sequences by using K information bits as 1 data symbol and corresponding to 2 K power states represented by 1 data symbol.
In a communication device equipped with a transmitter and a receiver using the M-array spread spectrum system, which selects one spread code and performs communication by a signal spread in spectrum with the spread code, transmitting the data symbol to the transmitter. And a means for transmitting a pilot channel spread by a spreading code different from the 2 K-th power type spreading code sequence used for
The receiver is provided with means for receiving the pilot channel, reproducing the transmission timing and synchronizing the transmission timing, and has an effect that the spreading code can be easily synchronized.

Further, in the invention described in claims 3 and 4, the information bits K bits are defined as one data symbol.
Corresponding to the 2 K power states represented by one data symbol, one spreading code is selected from 2 K power spreading code sequences, and communication is performed using signals spread in spectrum with the spreading code. In a communication device including a transmitter and a receiver using the M-array spread spectrum method, the transmitter includes a number of 2 K power types used for transmission of the data symbols in some specific symbols in a transmission frame. A means for transmitting a pilot symbol spread by any one specific spreading code of the spreading code sequences or by a spreading code different from the spreading code sequence of the K-th power type of 2 is provided to the receiver, Means for receiving the pilot symbols, reproducing and synchronizing the transmission timing, and some pilot symbols in the transmission frame,
Alternatively, it is provided with means for estimating the phase rotation of the transmission path of the preceding and following data symbols from the rotation of the phase of a plurality of pilot symbols over a plurality of transmission frames, and it is easy to synchronize the spread codes. It has an effect of being able to improve the communication quality by correcting the rotation of the phase of the transmission path.

Further, in the invention described in claims 5 and 6, the information bits K bits are defined as one data symbol.
Corresponding to the K powers of 2 represented by one data symbol, one of the combinations nCr that selects r spread codes from the n kinds of spread code sequences is selected, and the selected r In a communication device including a transmitter and a receiver using a parallel combinatory spread spectrum system, which performs communication by a signal obtained by phase-spreading a spread code by (n × 360 / L) degrees, transmission to the transmitter In some specific symbols in a frame, one specific spreading code of any one of n kinds of spreading code sequences used for transmission of the data symbol, or a spreading code different from the n kinds of spreading code sequences. Comprising means for transmitting pilot symbols that have not rotated the phase spread by
From the means for receiving the pilot symbols to the receiver, reproducing and synchronizing the transmission timing and synchronizing the transmission timing with some pilot symbols in the transmission frame or the rotation of the phase of the pilot symbols over the transmission frames. , A structure for estimating the rotation of the phase of the preceding and following data symbols due to the transmission line, and the effect that the spread codes can be easily synchronized, and the rotation of the phase of the transmission line is corrected. The communication quality can be improved.

Embodiments of the present invention will be described below with reference to FIGS. 1 to 7.

(First Embodiment) FIG. 1 is a block diagram of an M-array spread spectrum communication apparatus, which is composed of a transmitter and a receiver.

First, regarding the structure of the transmitter, the transmission data 1 is digital information transmitted from the transmission side to the reception side. The convolutional encoder 2 convolutionally encodes the transmission data 1 and includes a shift register or the like. The interleave circuit 3 performs time interleaving of coded bits, and is composed of a memory circuit for storing an interleave matrix / function.

The mapping circuit 4 selects one spread code corresponding to the transmission data from the 2K power spread codes from the spread code (1) to the spread code (K power of 2). is there. The spread code generation circuit 5 is for generating a selected spread code, and is configured by a shift register or the like, or a storage circuit that stores a spread code generated in advance.

The pilot signal generating circuit 6 is for generating a spreading code (0) for the pilot signal, and is composed of a shift register or the like or a memory circuit for storing the spreading code generated in advance. The combiner 7 combines (multiplexes) the spread signal of the information and the spread signal of the pilot signal.
Is what you do. The modulator 8 modulates a carrier frequency with a baseband signal. The antenna 9 emits a radio wave having a modulated carrier frequency.

Next, regarding the configuration of the receiver, the antenna 10
Receives a radio wave having a carrier frequency. The demodulator 11 demodulates and extracts a baseband signal from the modulated carrier signal. The synchronization circuit 12 is composed of a correlator for despreading the baseband signal of the pilot signal and a circuit for capturing / maintaining synchronization from the correlation value.

The correlator 13 despreads the baseband signal for the information signal. The deinterleave circuit 14 is
It performs reverse processing of time interleaving, and is composed of a memory circuit and the like. The Viterbi decoder 15 reproduces information by Viterbi decoding from the deinterleaved correlation value of each spreading code. The reception data 16 is digital information reproduced on the reception side.

The operation of the M-array spread spectrum communication device configured as described above will be described.

First, 1 bit of the transmission data 1 is (K × G) / by the convolutional encoder 2 having the coding rate J / (K × G).
It is encoded into a J-bit codeword and is input to the interleave circuit 3 for every K bits. In the interleave circuit 3,
(L × M) K-bit codewords are input, the temporal order is rearranged as shown in FIG. 2A, and output to the spreading code mapping circuit 4.

In the mapping circuit 4, a spreading code sequence of 2 K power types, from spreading code (1) to spreading code (2 K power), according to the type of 2 K powers of the input code word. One spread code is selected from among these, and the result is input to the spread code generation circuit 5.

The spread code generation circuit 5 generates the spread code selected by the spread code mapping circuit 4 and inputs the spread signal of information to the synthesizer 7. On the other hand, the pilot signal generation circuit 6 is for spreading pilot signals which are spreading codes other than the 2 K spreading codes from the spreading code (1) to the spreading code (2 K power) used for data transmission. The code (0) is generated and spread to generate a spread signal of the pilot signal, which is input to the combiner 7. The spread signal of the information signal and the spread signal of the pilot signal are added in the combiner 7, converted into a carrier frequency signal in the modulator 8, and transmitted from the transmitting antenna 9.

The transmitted carrier frequency signal is received by the antenna 10, converted into a baseband signal by the demodulator 11, and input to the synchronizing circuit 12 and the correlator 13. The synchronization circuit 12 synchronizes the spreading code by detecting the correlation value with the spreading code (0) used for the pilot signal constantly transmitted by the transmitter.

The correlator 13 uses the synchronization timing reproduced by the synchronization circuit 12 to obtain the received signals for all spreading codes of the 2 K power type from spreading code (1) to spreading code (2 K power). The correlation value is detected, and a set of 2 K power correlation values is input to the deinterleave circuit 14.

The deinterleave circuit 14 restores the set of correlation values in the time order exchanged by the interleave circuit 3 of the transmitter to the original time order as shown in FIG. 2 (2) and inputs it to the Viterbi decoder 15. The Viterbi decoder 15 carries out Viterbi decoding using the inputted set of 2 K power correlation values as branch metrics for soft decision, and obtains received data 16. However, one branch is composed of G / J symbols.

Since the correlator 13 detects a correlation value with respect to a certain spreading code (S), the information signal spread with the spreading code different for each symbol, that is, the correlation with the symbol spread with the spreading code (S) is used. Although the value is detected, the correlation value is not detected except for the symbols spread by the spreading code (S).

However, according to the first embodiment of the present invention, in addition to the information signal spread by the spreading code which is different for each symbol depending on the content of the information bit, any symbol is irrespective of the content of the information bit. It is possible to combine and transmit pilot signals spread by the same spreading code (0).

Therefore, it is possible to detect the correlation value for each symbol by detecting the correlation value of the pilot signal spread by the same spreading code (0) in every symbol by the spreading code (0).

In a bad environment such as multipath fading, the transmission path of mobile communication obtains the timing of correlation value determination from 2K power correlation values of information signals spread by different spreading codes for each symbol. That is actually quite difficult.

If there is a correlation value detected for each symbol, such as a correlation value of a pilot signal spread by the same spreading code (0) in every symbol, it is easier and more accurate to obtain the timing for measuring the correlation value. become.

Further, since the pilot signal can be used to more accurately estimate the rotation of the phase of the transmission line, the RAKE reception parameter for synthesizing the correlation value of the delayed wave can be more accurately determined.

Therefore, by these, the effect of improving the communication quality can be obtained. Further, in CDMA, which is one of the spread spectrum communications, the subscriber capacity can be expanded within a range that satisfies a certain communication quality, so that the improvement of the communication quality also has the effect of increasing the subscriber capacity.

As described above, according to the first embodiment of the present invention, by providing means for transmitting and receiving a pilot signal in which every symbol is spread with the same spreading code regardless of information bits, the correlation value is determined. It is possible to reproduce the determination timing easily and accurately, more accurately determine the RAKE reception parameter, improve communication quality, and thus increase the subscriber capacity.

In the above description, an example in which the ratio of addition / combination of the information signal and the pilot signal is equal has been described, but the specific gravity of the pilot signal is increased, decreased, or increased for some symbols. The same can be applied to the case of lowering or lowering.

In the above description, an example in which a convolutional encoder and a Viterbi decoder are used has been described, but a similar configuration can be implemented when a block code encoder / decoder is used. When error correction is not performed, the transmitter is provided with a serial-parallel conversion circuit that collects the transmission data 1 for every K bits and inputs the data to the mapping circuit 4 instead of the convolutional encoder 2 and the interleave circuit 3. Then, the receiver can be replaced by the deinterleaving circuit 14 and the Viterbi decoder 15, and a decision circuit for deciding one spreading code from a set of 2 K correlation values can be used to perform the same operation. Is. Note that J, K, L, M, and n are natural numbers. [Detailed Description of the Invention]

(Second Embodiment) FIG. 5 shows a configuration diagram of a transmission frame used in the M-array spread spectrum communication apparatus.

The frame is a control symbol 61 generated from pilot symbols which are known bits and coded bits obtained by error-correcting coding control bits used for communication control.
And a data symbol 62 generated from coded bits obtained by error-correcting coding the user information bits.

This drawing shows an example in which the pilot symbol is divided into two, a pilot symbol H63 and a pilot symbol T64 arranged at the beginning of the frame. The control bit and the information bit are not necessarily error correction coded, and even when they are error correction coded, they are not necessarily error correction coded separately.

FIG. 4 is a block diagram of an M-array spread spectrum communication device, which is composed of a transmitter and a receiver.

First, regarding the structure of the transmitter,
Reference numeral 41 is digital information transmitted from the transmitting side to the receiving side, and is composed of information bits and control bits. The convolutional encoder 42 convolutionally encodes the transmission data 41, and includes a shift register or the like. The interleave circuit 43 performs time interleaving of coded bits, and is composed of a memory circuit for storing an interleave matrix / function.

The frame assembling circuit 44 assembles a transmission frame from time-interleaved convolutionally coded bits and the like. The mapping circuit 45 uses the spreading code (0) and the spreading code (1) to the spreading code (2 to the Kth power) (2
One of the spreading codes corresponding to the symbol to be transmitted is selected from the (Kth power of 1 + 1) spreading codes.

The spread code generating circuit 46 is for generating the selected spread code, and is composed of a shift register or the like or a storage circuit for storing the spread code generated in advance. The modulator 47 modulates a carrier frequency with a baseband signal. The antenna 48 emits a radio wave having a modulated carrier frequency.

Next, regarding the configuration of the receiver, the antenna 49
Receives a radio wave having a carrier frequency. The demodulator 50 demodulates / extracts a baseband signal from the modulated carrier signal. The frame disassembling circuit 51 disassembles the received transmission frame and inputs it to the synchronizing circuit 52 and the correlator 53, respectively.

The synchronizing circuit 52 is composed of a correlator for despreading the baseband signal for the spread code (0) and a circuit for capturing and maintaining synchronization from the correlation value. The correlator 53 despreads the baseband signal with respect to n spread codes from the spread code (1) to the spread code (2 to the Kth power).

The deinterleave circuit 54 performs reverse processing of time interleave, and is composed of a memory circuit and the like. The Viterbi decoder 55 reproduces information by Viterbi decoding from the deinterleaved correlation value of each spreading code. The received data 56 is digital information reproduced on the receiving side.

The operation of the M array spread spectrum communication device configured as described above will be described.

First, one bit of the transmission data 41 is (K × G) / concatenated by the convolutional encoder 42 of the coding rate J / (K × G).
It is encoded into a J-bit code word and is input to the interleave circuit 43 for every K bits. In the interleave circuit 43,
(L × M) K-bit codewords are input, and the frame assembling circuit 44 is arranged by rearranging the temporal order as shown in FIG.
To enter.

The frame assembling circuit 44 generates data symbols and control symbols from the interleaved convolutionally coded bits K bits, assembles a transmission frame by combining known pilot symbols, and directs them to the spread code mapping circuit 45. Output.

In the mapping circuit 45, the spreading code (0) is selected if it is a pilot symbol, and if it is a data symbol or a control symbol, the spreading code (0) is selected according to the type of 2 K powers of the input code word. One spreading code is selected from the spreading code series of 2 K power types from 1) to the spreading code (K power of 2), and the result is input to the spreading code generation circuit 46.

The spread code generation circuit 46 generates and spreads the spread code selected by the spread code mapping circuit 45 and inputs the spread signal to the modulator 47. The spread signal is a modulator 47
At, the signal is converted into a carrier frequency signal and transmitted from the transmitting antenna 48.

The transmitted carrier frequency signal is received by the antenna 49, converted into a baseband signal by the demodulator 50, and input to the frame decomposing circuit 51. The frame decomposition circuit 51 decomposes the received baseband signal and inputs it to the synchronization circuit 52 and the correlator 53. Synchronous circuit 52
Then, the spreading code is synchronized by detecting the correlation value of the pilot symbol, which is a known symbol, with the spreading code (0).

The correlator 53 uses the synchronization timing reproduced by the synchronization circuit 52 to process the received signals for all spreading codes of 2 K power types from spreading code (1) to spreading code (2 K power). The correlation value is detected and the phases of data symbols and control symbols are corrected from the phases of several pilot symbols before and after, and
A set of K power correlation values is input to the deinterleave circuit 54.

The deinterleave circuit 54 restores the set of correlation values in the time order exchanged by the interleave circuit 43 of the transmitter to the original time order as shown in FIG. 2 (2) and inputs it to the Viterbi decoder 55.

The Viterbi decoder 55 carries out Viterbi decoding using the inputted set of K 2 correlation values as a soft-decision branch metric to obtain received data 56. However, G /
One branch is composed of J symbols.

Since the correlator 53 detects a correlation value with respect to a certain spreading code (S), the information signal spread with the spreading code different for each symbol, that is, the correlation with the symbols spread with the spreading code (S) is used. Although the value is detected, the correlation value is not detected except for the symbols spread by the spreading code (S).

However, according to the second embodiment of the present invention, in addition to the information signal spread by the spreading code different for each symbol depending on the content of the information bit, the specific symbol is irrespective of the content of the information bit. In, it is possible to transmit and receive known pilot symbols spread with a specific spreading code (0).

Therefore, a known pilot symbol spread with a specific spreading code (0) in a specific symbol is used to detect a correlation value with the spreading code (0) to periodically obtain a correlation value at regular intervals. Can be detected.

In a bad environment such as multipath fading, the transmission path of mobile communication obtains the timing for determining the correlation value from the 2K power correlation values of the information signal spread by different spreading codes for each symbol. That is actually quite difficult.

If there is a correlation value that is regularly detected at a constant interval, such as a correlation value of a known pilot symbol spread by a specific spreading code (0) in a specific symbol, the timing for measuring the correlation value is set. Easier to get,
And become accurate.

Further, as compared with the system in which pilot signals are always multiplexed for transmission / reception, the number of signals to be multiplexed is reduced, and the interference between the signals is reduced accordingly, so that the communication quality is improved.

Also, with known pilot symbols,
The rotation of the phase of the transmission line can be easily estimated. Then, it is possible to more accurately estimate the phase rotation and the like due to the transmission paths of the data symbols and the control symbols between these pilot symbols before and after.
Therefore, the RAKE reception parameter for combining the correlation values of the delayed waves can be more accurately determined.

Therefore, by these, the effect of improving the communication quality can be obtained. Further, in CDMA, which is one of the spread spectrum communications, the subscriber capacity can be expanded within a range that satisfies a certain communication quality, so that the improvement of the communication quality also has the effect of increasing the subscriber capacity.

As described above, according to the second embodiment of the present invention, by providing means for transmitting / receiving a known pilot symbol spread by a specific spreading code in a specific symbol regardless of information bits, The timing for determining the correlation value can be easily and accurately reproduced, and the RAKE reception parameter can be more accurately determined, so that the communication quality can be improved and the subscriber capacity can be increased.

In the above description, an example in which the transmission power ratios of the data symbols and control symbols are the same as those of the pilot symbols has been described. However, the specific gravity of the pilot symbols may be increased or decreased, or some pilots may be used. The same can be applied to the case of raising or lowering the symbol.

In the above description, an example in which a convolutional encoder and a Viterbi decoder are used has been described. However, the same configuration can be implemented when a block code encoder / decoder is used.

When error correction is not performed, the transmitter is connected to the convolutional encoder 42 and the interleave circuit 43 instead of the convolutional encoder 42 and the interleave circuit 43. By installing a conversion circuit and installing in the receiver, instead of the deinterleave circuit 54 and the Viterbi decoder 55, a determination circuit that determines one spreading code from a set of 2 K correlation values, It can be similarly implemented.

Further, in the above description, as the spreading code (0) for spreading the pilot symbols, the spreading code (1) for spreading the data symbols and the control symbols to the spreading code (K power of 2) to the 2 Kth power. Although an example of using a spreading code other than the individual spreading codes has been described, the spreading code (0)
The same configuration can be implemented by using the same code as any one of the spread code (1) to the spread code (2 to the Kth power). In this case, the number of spreading codes used is the same as that of the conventional M-array spread spectrum communication device, and there is an effect that it is not necessary to prepare a new spreading code.

(Third Embodiment) FIG. 7 shows a configuration diagram of a transmission frame used in the parallel combination spread spectrum communication apparatus.

The frame includes control symbols 91 generated from pilot symbols which are known bits and coded bits obtained by error-correcting coding control bits used for communication control.
And a data symbol 92 generated from coded bits obtained by error-correcting coding the user information bits.

This drawing shows an example in which the pilot symbol is divided into two, a pilot symbol H93 and a pilot symbol T94 arranged at the beginning of the frame. The control bit and the information bit are not necessarily error correction coded, and even when they are error correction coded, they are not necessarily error correction coded separately.

FIG. 6 is a block diagram of a parallel combination spread spectrum communication apparatus, which is composed of a transmitter and a receiver.

First, regarding the structure of the transmitter,
71 is digital information transmitted from the transmitting side to the receiving side, and is composed of information bits and control bits. The convolutional encoder 72 convolutionally encodes the transmission data 71, and is composed of a shift register or the like. The interleave circuit 73 performs time interleaving of encoded bits, and is composed of a memory circuit that stores an interleave matrix / function.

The frame assembling circuit 74 assembles a transmission frame from time-interleaved convolutionally coded bits and the like. The mapping circuit 75 selects a spreading code (0) as a pilot symbol, and a spreading symbol (0) as a data symbol and a control symbol as a symbol to be transmitted from n spreading codes (1) to (n). The corresponding r spreading codes are selected.

The spread code generation circuit 76 is for generating the selected spread code, and is composed of a shift register or the like, or a storage circuit for storing the spread code generated in advance. The combiner 77 rotates the phases of the generated spread signals and combines them, and is composed of a phase rotation circuit and an addition circuit. The modulator 78 modulates the carrier frequency with a baseband signal. The antenna 79 emits a radio wave having a modulated carrier frequency.

Next, regarding the configuration of the receiver, the antenna 80
Receives a radio wave having a carrier frequency. The demodulator 81 demodulates and extracts a baseband signal from the modulated carrier signal. The frame decomposing circuit 82 decomposes the received transmission frame and inputs it into the synchronizing circuit 83 and the correlator 84, respectively.

The synchronizing circuit 83 is composed of a correlator for despreading the baseband signal for the spread code (0) and a circuit for capturing / maintaining synchronization from the correlation value. In the correlator 84, n from spreading code (1) to spreading code (n)
Despread the baseband signal for each spreading code.

The deinterleave circuit 85 performs the inverse process of the time interleave, and is composed of a memory circuit and the like. The Viterbi decoder 86 reproduces information from the deinterleaved spread code correlation values by Viterbi decoding. The received data 87 is digital information reproduced on the receiving side.

The operation of the parallel combination spread spectrum communication apparatus configured as described above will be described.

First, 1 bit of the transmission data 71 is (K × G) / by the convolutional encoder 72 of the coding rate J / (K × G).
It is encoded into a J-bit codeword and is input to the interleave circuit 73 every K bits. In the interleave circuit 73,
A (L × M) number of K-bit codewords are input, the temporal order is rearranged as shown in FIG.
To enter.

The frame assembling circuit 74 generates data symbols and control symbols from the interleaved convolutional coded bits K bits, assembles a transmission frame by combining known pilot symbols, and makes the spreading code mapping circuit 75. To output.

In the mapping circuit 75, the spreading code (0) is selected if it is a pilot symbol, and if it is a data symbol or a control symbol, the spreading code (0) is selected according to the type of 2 K powers of the input code word. 1) to spreading code (n)
The spreading code generation circuit selects the spreading code type and the phase of r spreading codes from the n spreading code sequences up to
The rotation angle of the phase is input to 76 and to the synthesis circuit 77, respectively.

In the spread code generation circuit 76, the mapping circuit 75
The spread code selected in 1 is generated and spread, and the spread signal is input to the combiner 77. The synthesizer 77 is a spread code generation circuit.
The spread signals generated in 76 are phase-rotated by the rotation angle selected in the mapping circuit 75, and are combined. The combined spread signal is converted into a carrier frequency signal in the modulator 78 and transmitted from the transmitting antenna 79.

The transmitted carrier frequency signal is received by the antenna 80, converted into a baseband signal by the demodulator 81, and input to the frame decomposing circuit 82. The frame decomposition circuit 82 decomposes the received baseband signal and inputs it to the synchronization circuit 83 and the correlator 84.

The synchronizing circuit 83 synchronizes the spreading code by detecting the correlation value of the pilot symbol which is a known symbol with the spreading code (0). In the correlator 84,
Using the synchronization timing reproduced by the synchronization circuit 83,
It detects the correlation value of the received signal for all n kinds of spreading codes from spreading code (1) to spreading code (n), and detects the phase of data symbols and control symbols from the phases of several pilot symbols before and after. Are corrected and n sets of correlation values are input to the deinterleave circuit 85.

In the deinterleave circuit 85, the set of correlation values in the time order exchanged by the interleave circuit 73 of the transmitter is returned to the original time order as shown in FIG. 2 (2) and is input to the Viterbi decoder 86. The Viterbi decoder 86 performs Viterbi decoding using the set of n input correlation values as a soft-decision branch metric to obtain received data 87. Where G
The / J symbol constitutes one branch.

Since the correlator 84 detects a correlation value with respect to a certain spreading code (S), the information signal spread with a spreading code different for each symbol, that is, the symbols spread with the spreading code (S) are correlated. Although the value is detected, the correlation value is not detected except for the symbols spread by the spreading code (S).

However, according to the third embodiment of the present invention, in addition to the information signal spread by the spreading code which is different for each symbol depending on the content of the information bit, the specific symbol is irrespective of the content of the information bit. In, it is possible to transmit and receive known pilot symbols that have been spread with a specific spreading code (0) and rotated to a specific phase.

Therefore, a known pilot symbol which is spread with a specific spreading code (0) and is rotated to a specific phase in a specific symbol is detected at a constant interval by detecting a correlation value with the spreading code (0). The correlation value can be detected regularly.

In a bad environment such as multipath fading, the transmission path of mobile communication obtains the timing of correlation value determination from 2K power correlation values of information signals spread by different spreading codes for each symbol. That is actually quite difficult.

If there is a correlation value that is regularly detected at regular intervals, such as the correlation value of a known pilot symbol that is spread with a specific spreading code (0) and is rotated to a specific phase in a specific symbol, Obtaining the timing of the correlation value measurement is also easier and more accurate.

Further, compared with the system in which pilot signals are always multiplexed for transmission / reception, the number of signals to be multiplexed is reduced, and the interference between the signals is reduced accordingly, and the effect of improving communication quality can be obtained.

Further, the pilot symbol of the known phase makes it possible to easily estimate the rotation of the phase of the transmission path. Then, it is possible to more accurately estimate the phase rotation and the like due to the transmission paths of the data symbols and the control symbols between these pilot symbols before and after. Therefore, the RAKE reception parameter for combining the correlation values of the delayed waves can be more accurately determined.

Therefore, by these, the effect of improving the communication quality can be obtained. Further, in CDMA, which is one of the spread spectrum communications, the subscriber capacity can be expanded within a range that satisfies a certain communication quality, so that the improvement of the communication quality also has the effect of increasing the subscriber capacity.

As described above, according to the third embodiment of the present invention, by providing means for transmitting / receiving a known pilot symbol spread by a specific spreading code in a specific symbol regardless of information bits, The timing for determining the correlation value can be easily and accurately reproduced, and the RAKE reception parameter can be more accurately determined, so that the communication quality can be improved and the subscriber capacity can be increased.

In the above description, the case where the transmission power ratios of the data symbol and control symbol and the pilot symbol are equal has been described, but the specific gravity of the pilot symbol may be increased or decreased, or a part of the pilot symbol may be reduced. The same can be applied to the case of raising or lowering the symbol.

Further, in the above description, an example in which a convolutional encoder and a Viterbi decoder are used has been described, but a similar configuration can be implemented when a block code encoder / decoder is used.

When error correction is not performed, the transmitter is connected to the convolutional encoder 72 and the interleave circuit 73 instead of the convolutional encoder 72. A conversion circuit is installed, and instead of the deinterleave circuit 85 and the Viterbi decoder 86, a determination circuit that determines one spreading code from a set of n correlation values is installed in the receiver, and the same operation is performed. It is possible.

Further, in the above description, as the spreading code (0) for spreading the pilot symbols, the n spreading codes from spreading code (1) to spreading code (n) for spreading the data symbols and control symbols are Although an example in which another spreading code is used has been described, the same configuration can be implemented by using the same code as any one of the spreading codes (1) to (n) as the spreading code (0). . in this case,
The number of spread codes used is the same as that of the conventional parallel combination spread spectrum communication apparatus, and there is an effect that it is not necessary to prepare a new spread code.

[0109]

As described above, the present invention transmits a pilot channel spread by a spreading code different from the 2 K power spreading codes used for data transmission in a transmitter,
The receiver is configured to receive the pilot channel and synchronize the received signal, or the transmitter transmits a pilot symbol spread by a specific spreading code in a specific symbol and rotated to a specific phase, and receiving By configuring the device to receive the pilot symbol and synchronize the received signal, the effect that the received signal can be easily synchronized is obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram according to a first embodiment of the present invention,

FIG. 2 is a conceptual diagram of operations of an interleave circuit and a deinterleave circuit,

FIG. 3 is a configuration diagram of a conventional example,

FIG. 4 is a configuration diagram according to a second embodiment of the present invention,

FIG. 5 is a diagram showing a configuration of a transmission frame according to the second embodiment of the present invention,

FIG. 6 is a configuration diagram according to a third embodiment of the present invention,

FIG. 7 is a configuration diagram of a transmission frame according to the third embodiment of the present invention.

[Explanation of symbols]

 1, 30, 41, 71 Transmission data 2, 42, 72 Convolutional encoder 3, 43, 73 Interleave circuit 4, 31, 45, 75 Mapping circuit 5, 32, 46, 76 Spread code generation circuit 6 Pilot signal generator 7, 77 Combiner 8, 47, 78 Modulator 9, 35, 48, 79 Transmit antenna 10, 36, 49, 80 Receive antenna 11, 37, 50, 81 Demodulator 12, 52, 83 Synchronous circuit 13, 38, 53, 84 Correlator 14, 54, 85 Deinterleave circuit 15, 55, 86 Viterbi decoder 16, 40, 56, 87 Received data 33 Adder 39 Demapping circuit 44, 74 Frame assembly circuit 51, 82 Frame decomposition circuit

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Eiji Katsura 4-3-1, Tsunashima-higashi, Kohoku-ku, Yokohama-shi, Kanagawa Matsushita Communication Industrial Co., Ltd.

Claims (6)

[Claims] 1. Information bit K bits (where K is a natural number) is defined as one data symbol, and this data symbol 1
Corresponding to the K powers of 2 represented, one spreading code is selected from the spreading code sequences of the 2 K power types, and communication is performed by signals spread by the spreading code. In a communication device including a transmitter and a receiver using the method, a pilot channel spread by a spreading code different from a spreading code sequence of 2 K type used for transmission of the data symbols is provided to the transmitter. A spread spectrum communication device comprising means for transmitting, and means for receiving the pilot channel, reproducing the transmission timing, and synchronizing with the receiver. 2. Convolutional coding is performed on the information bits, and K bits (where K is a natural number) of the coded error correction coded sequence are defined as one data symbol, and one of the two data symbols is represented. Corresponding to K powers,
In a communication device equipped with a transmitter and a receiver using the M-array spread spectrum system, which selects one spread code from 2 K kinds of spread code sequences and performs communication with a signal spread spectrum by the spread code In the transmitter, an interleaving means for rearranging the time sequence of the error correction coded sequence in K bits as a unit, and a spreading code different from the 2 K power type spreading code sequence used for transmission of the data symbol are used. Means for transmitting a spread pilot channel, means for receiving the pilot channel, reproducing transmission timing for synchronization, and restoring the time order of the sequences rearranged by the interleaving to the receiver Deinterleaving means and correlation detection are performed for all spreading codes of the 2 K power type, and a set of 2 K power correlation values is used for soft decision. Spread spectrum communication apparatus having an error correction decoding means for Viterbi decoding as lunch metric. 3. Information bit K bits (where K is a natural number) is defined as one data symbol, and this data symbol 1
Corresponding to the K powers of 2 represented, one spreading code is selected from the spreading code sequences of the 2 K power types, and communication is performed by signals spread by the spreading code. In a communication device including a transmitter and a receiver using the method, the transmitter includes a number of 2 K-type spreading code sequences used for transmission of the data symbols in some specific symbols in a transmission frame. A means for transmitting a pilot symbol spread by any one of these specific spreading codes or by a spreading code different from the 2nd K power type spreading code sequence is provided, and the pilot symbol is transmitted to the receiver. A means of receiving and regenerating and synchronizing the transmission timing and some pilot symbols in the transmission frame, or multiple transmissions across multiple transmission frames. Spread spectrum communication system from the rotation of the phase of the pilot symbols, comprising means for estimating the phase rotation due to transmission path before and after the data symbols. 4. Convolutional coding is performed on the information bits, and K bits (where K is a natural number) of the coded error-correction coded sequence are defined as one data symbol, and each data symbol represents two. Corresponding to K powers,
In a communication device equipped with a transmitter and a receiver using the M-array spread spectrum system, which selects one spread code from 2 K kinds of spread code sequences and performs communication with a signal spread spectrum by the spread code Interleaving means for rearranging the time sequence of the error correction coded sequence in units of K bits in the transmitter, and 2 K power used for transmission of the data symbols in some specific symbols in a transmission frame. A receiver for transmitting a pilot symbol spread by any one specific spreading code of the spreading code sequences of different types or by a spreading code different from the spreading code sequence of the K-th power type of 2; Means for receiving the pilot symbols to recover and synchronize the transmission timing, and some pilot sequences in the transmission frame. Based on the time sequence of the sequences rearranged by the interleaving, and a means for estimating the rotation of the phase due to the transmission path of the preceding and following data symbols from the rotation of the phase of a plurality of pilot symbols over a plurality of transmission frames. Deinterleaving means for returning, and correlation detection for all spreading codes of the 2 K power type,
A spread spectrum communication apparatus comprising: an error correction decoding means for performing Viterbi decoding using a set of 2 K power correlation values as a soft decision branch metric. 5. Information bit K bits (where K is a natural number) is defined as one data symbol, and this data symbol 1
Corresponding to K powers of 2 represented by r, r spreading codes (where r is a natural number) are selected from n kinds of spreading code sequences (where n is a natural number and is an integer of 0 or more and less than L). Combination One of nCr combinations is selected, the selected r spread codes are phase-rotated by (n × 360 / L) degrees (where L is a natural number), and communication is performed by a multiplexed signal. A parallel combination. In a communication device including a transmitter and a receiver using a spread spectrum method, the transmitter includes a number of n kinds of spreading code sequences used for transmission of the data symbol in some specific symbols in a transmission frame. , A means for transmitting a pilot symbol whose phase is not rotated by one specific spreading code or a spreading code different from the above-mentioned n-type spreading code sequence, From the means for receiving the pilot symbols to the receiver, reproducing and synchronizing the transmission timing and synchronizing the transmission timing with some pilot symbols in the transmission frame or the rotation of the phase of the pilot symbols over the transmission frames. , A spread spectrum communication device comprising means for estimating the rotation of the phase due to the transmission paths of preceding and following data symbols. 6. Convolutional coding is performed on the information bits, and K bits (where K is a natural number) of the coded error correction coded sequence are defined as one data symbol, and two of these data symbols are represented. Corresponding to K powers,
A combination of n (where r is a natural number) spreading code is selected from n types (where n is a natural number and is an integer of 0 or more and less than L), and one of nCr combinations is selected and selected r Communication including a transmitter and a receiver using a parallel combinatory spread spectrum system, in which communication is performed by a signal obtained by phase-rotating each spreading code by (n × 360 / L) degrees (where L is a natural number) In the apparatus, the transmitter includes interleaving means for rearranging the time sequence of the error correction coded sequence in units of K bits, and n kinds used for transmission of the data symbols in some specific symbols in a transmission frame. Specific spreading code of any one of the spreading code sequences of
A means for transmitting a pilot symbol whose phase is not rotated by a spreading code different from the type of spreading code sequence is provided, and the receiver receives the pilot symbol and reproduces the transmission timing to establish synchronization. Means for estimating the rotation of the phase due to the transmission path of the preceding and following data symbols from the rotation of the phase of some pilot symbols in the transmission frame or the pilot symbols over the plurality of transmission frames; Deinterleaving means for returning the time sequence of the rearranged sequence to the original, and correlation detection for all n kinds of spreading codes, and error correction decoding for performing Viterbi decoding using a set of n correlation values as a soft-decision branch metric. And a spread spectrum communication device.