JP2008206045A - Wireless communication system and wireless device - Google Patents

Abstract

A wireless communication system and a wireless device capable of performing optimal signal transmission according to the magnitude of received signal power of a receiver.
In a wireless communication system, one wireless device A, B, C,..., N, a, b,..., M is a transmission system for both single carrier transmission and multicarrier transmission. The other radios A, B, C,..., N, a, b,..., M have transmission modes for both single carrier transmission and multicarrier transmission. A power reference value serving as a reference for received signal power in the one or other radio devices A, B, C,..., N, a, b,. When the received signal power is less than or equal to the power reference value, transmission / reception is performed using the single carrier transmission mode, and when the received signal power is greater than or equal to the power reference value, the multicarrier Sending and receiving using transmission mode
[Selection] Figure 1

Description

  The present invention relates to a wireless communication system and a wireless device.

Conventionally, single carrier transceivers and multicarrier transceivers have been used as transceivers (see, for example, Non-Patent Documents 1 and 2).
First, the transmission / reception function of a conventional single carrier transceiver will be described.
FIG. 7 is a block diagram showing a conventional single carrier transmitter for each function.
In the figure, reference numeral 101 indicates a channel encoding unit, reference numeral 102 indicates a data modulation unit, reference numeral 103 indicates a guard interval (GI) insertion unit, reference numeral 104 indicates a waveform shaping unit, reference numeral 105 indicates a radio unit, reference numeral 106 indicates A transmitting antenna is shown.
Under such a configuration, at the time of transmission, after the transmission data sequence is encoded by the channel encoding unit 101, the data modulation unit 102 performs PSK or QAM modulation to generate a transmission symbol sequence. Then, the GI insertion unit 103 inserts the GI. Further, after waveform shaping (filtering) is performed by the waveform shaping unit 104, a signal is transmitted from the transmission antenna 106 via the radio unit 105.

FIG. 8 is a block diagram showing a conventional single carrier receiver for each function.
In the figure, reference numeral 111 denotes a receiving antenna, reference numeral 112 denotes a radio unit, and reference numeral 113 denotes a GI removing unit. Reference numeral 114 denotes a discrete Fourier transform unit, reference numeral 115 denotes a frequency domain equalization unit, and reference numeral 116 denotes an inverse Fourier transform unit. Reference numeral 117 denotes a data demodulator, and reference numeral 118 denotes a channel decoder.
Under such a configuration, at the time of reception, a single carrier transmission signal transmitted from another radio device is received by the receiving antenna 111, and the GI is removed by the GI removing unit via the radio unit 112. The Further, the frequency component of the received signal is obtained by the discrete Fourier transform unit 114, and channel equalization is performed by the frequency domain equalization unit 115. Then, after equalizing the waveform, the inverse discrete Fourier transform unit 116 converts the waveform into a time signal. Further, data demodulation and channel decoding are performed by the data demodulating unit 117 and the channel decoding unit 118, and the data is reproduced and sent to a predetermined processing unit.

Next, the transmission / reception function of the conventional multicarrier transceiver will be described.
FIG. 9 is a block diagram of a conventional multicarrier transmitter for each function.
In the figure, reference numeral 121 denotes a channel encoding unit, reference numeral 122 denotes a data modulation unit, and reference numeral 123 denotes a serial / parallel conversion unit. Reference numeral 124 denotes an inverse discrete Fourier transform unit, reference numeral 125 denotes a GI insertion unit, reference numeral 126 denotes a radio unit, and reference numeral 127 denotes a transmission antenna.
Under such a configuration, at the time of transmission, after the transmission data sequence is encoded by the channel encoding unit 121, the data modulation unit 122 performs PSK or QAM modulation to generate a transmission symbol sequence. Then, after the multi-carrier signal is generated by the serial / parallel conversion unit 123 and the inverse discrete Fourier transform unit 124, the GI insertion unit 125 inserts the GI in the obtained transmission symbol sequence. Further, the signal is transmitted by the transmission antenna 127 via the wireless unit 126.

FIG. 10 is a block diagram of a conventional multicarrier receiver for each function.
In the figure, reference numeral 131 denotes a receiving antenna, reference numeral 132 denotes a radio unit, and reference numeral 133 denotes a GI removing unit. Reference numeral 134 denotes a discrete Fourier transform unit, reference numeral 135 denotes a frequency domain equalization unit, and reference numeral 136 denotes a parallel / serial conversion unit. Reference numeral 137 denotes a data demodulator, and reference numeral 138 denotes a channel decoder.
Under such a configuration, at the time of reception, a multicarrier transmission signal transmitted from another wireless device is received by the receiving antenna 131, passes through the wireless unit 132, and then the GI removing unit 133 sets the GI. Removed. The frequency component of the received signal is obtained by the discrete Fourier transform unit 134, and channel equalization is performed by the frequency domain equalization unit 135. Furthermore, after the waveforms are equalized, the parallel / serial conversion unit 136 performs parallel / serial conversion. Then, the data demodulation unit 137 and the channel decoding unit 138 perform data demodulation and channel decoding, and the data is reproduced and sent to a predetermined processing unit.

As described above, when transmitting a signal from one radio to another radio, conventionally, either single carrier transmission or multicarrier transmission is used.
D. Falconer, S.M. L. Ariyavisitakul, A.A. Benyamin-Seeyer, B.M. Eidson, “Frequency Domain Equalization for Single-Carrier Broadband Wireless Systems”, IEEE Commun. Mag, vol. 40, no. 4, pp. 58-66, Apr. 2002 M.M. Okada, S .; Hara, N .; Morinaga, “Bit Error Rate Performances of Orthogonal Multicarrier Modulation Radio Transmission Systems”, IEICE Trans. Commun, vol. E76-B, no. 2, pp. 113-119, Feb. 1993

However, for example, when only multi-carrier transmission is used, when the signal power received at the mobile station or the base station decreases, it is necessary to increase the transmission signal power for transmission. However, in the case of multicarrier transmission, since the peak-to-average signal power ratio (PAPR) is large, there is a problem that if the transmission signal power is increased, the backoff of the transmission power amplifier is reduced and the transmission signal is distorted. .
On the other hand, if only single carrier transmission is used, the problem of PAPR is small. Therefore, in the non-linear region where the back-off must be reduced to some extent, the characteristics are better than multi-carrier transmission. There is a problem that characteristics deteriorate with respect to transmission.

  The present invention has been made in view of such circumstances, and provides a wireless communication system and a wireless device capable of performing optimal signal transmission according to the magnitude of the received signal power of the receiver. Objective.

In order to solve the above problems, the present invention provides the following means.
The present invention is a wireless communication system composed of at least a pair of wireless devices, wherein one wireless device has transmission modes of both single carrier transmission and multicarrier transmission, and the other wireless devices It has transmission modes for both single-carrier transmission and multi-carrier transmission, and a power reference value serving as a reference for received signal power in the one or other radio device is defined in advance, One radio transmits a signal using the single carrier transmission mode when the received signal power in the one or other radio is equal to or lower than the power reference value, and the received signal power Is equal to or greater than the power reference value, the multi-carrier transmission mode is used to transmit a signal, and the other radio is connected to the single radio by the single radio. When the signal is transmitted using the transmission mode, the signal is received using the single carrier transmission mode, and when the one radio device transmits the signal using the multicarrier transmission mode. Is characterized in that the signal is received using the multi-carrier transmission mode.

  The present invention also includes a distance estimation unit that estimates a distance between one radio and another radio in a radio communication system including at least a pair of radios. The unit has transmission modes for both single carrier transmission and multicarrier transmission, and the other radio unit has transmission modes for both single carrier transmission and multicarrier transmission. A distance reference value that is a reference for a distance between the one wireless device and the other wireless device is defined in advance, and the one wireless device has a distance estimated by the distance estimating means, If the distance reference value is greater than or equal to the distance reference value, a signal is transmitted using the single carrier transmission mode, and if the distance estimated by the distance estimation means is less than or equal to the distance reference value, the multi-key is transmitted. A signal is transmitted using a rear transmission mode, and the other wireless device transmits the signal using the single carrier transmission mode when the one wireless device transmits a signal using the single carrier transmission mode. When the one radio device transmits a signal using the multicarrier transmission mode, the signal is received using the multicarrier transmission mode.

  The present invention further includes a propagation path estimation means for estimating a delay spread between one radio and another radio in a radio communication system including at least a pair of radios. The radio of this embodiment has transmission modes for both single-carrier transmission and multi-carrier transmission, and the other radio has both transmission modes of single-carrier transmission and multi-carrier transmission. A delay reference value serving as a reference for a delay spread between the one radio and the other radio is defined in advance, and the one radio is estimated by the propagation path estimation unit. When the delay spread is equal to or less than the delay reference value, a signal is transmitted using the single carrier transmission mode, and the delay spread estimated by the propagation path estimation means is transmitted. When the delay reference value is greater than or equal to the delay reference value, the multi-carrier transmission mode is used to transmit a signal, and the other radio device transmits the signal using the single-carrier transmission mode. Receiving the signal using the single carrier transmission mode, and when the one radio transmits a signal using the multicarrier transmission mode, the multicarrier transmission mode is used to transmit the signal. A signal is received.

  Further, the present invention provides a wireless communication system including at least a pair of wireless devices, wherein one wireless device includes transmission modes of both single carrier transmission and multicarrier transmission, and other wireless devices. Has transmission modes for both single-carrier transmission and multi-carrier transmission, and a reception power reference value serving as a reference of reception signal power in the other radio is defined in advance, and the one radio A transmission power reference value serving as a reference of transmission signal power in the wireless communication device is defined in advance, and the other wireless device is connected to the one wireless device so that the reception signal power is equal to or higher than the reception power reference value. Requesting the transmission signal power, and the one radio transmits a signal using the single carrier transmission mode when the transmission signal power is more than the transmission power reference value. When the transmission signal power is less than or equal to the transmission power reference value, the multi-carrier transmission mode is used to transmit a signal, and the other radio is configured such that the one radio is in the single carrier transmission mode. If the signal is transmitted using the single-carrier transmission mode, the signal is received using the single-carrier transmission mode, and if the one radio device transmits the signal using the multi-carrier transmission mode, The signal is received using a multicarrier transmission mode.

  Further, in the present invention, the other radio device includes a single carrier transmission reception circuit and a multicarrier transmission reception circuit, and the single carrier transmission reception circuit converts an input signal into a plurality of orthogonal frequency components. A single carrier orthogonal transformer, a weighting unit for weighting each output of the single carrier orthogonal transformer, and an inverse orthogonal transformation for performing inverse orthogonal transformation on the signal weighted by the weighting unit A single carrier demodulating circuit that demodulates the output signal of the inverse orthogonal transformer, and a weighting control device that controls a weighting value in the weighting device, and the multicarrier transmission receiving circuit comprises: A multi-carrier orthogonal transformer that separates an input signal into a plurality of orthogonal frequency components, and the multi-carrier orthogonal transformer. A multi-carrier demodulating circuit that performs demodulation on each of the separated frequency components, and the single-carrier orthogonal transformer and the multi-carrier orthogonal transformer are used for the single-carrier transmission and the multi-carrier transmission, respectively. It is also used as a feature.

  According to the present invention, the at least one radio device includes a multi-carrier transmission circuit and a single-carrier transmission circuit, and the multi-carrier transmission circuit converts an input signal into a plurality of signal sequences. A serial-parallel conversion circuit for rearranging; and an output of the serial-parallel conversion circuit as an input signal of each frequency component, and an inverse orthogonal transformer for multicarrier that obtains a time-series signal by inverse orthogonal transformation, for the single carrier transmission The receiving circuit includes: an orthogonal transformer that separates an input signal into a plurality of orthogonal frequency components; a weighting unit that weights each output of the orthogonal transformer; and a signal weighted by the weighting unit. A single carrier inverse orthogonal transformer that performs orthogonal transformation; a demodulation circuit that demodulates an output signal of the single carrier inverse orthogonal transformer; A weight control device for controlling a weighting value in the attaching unit, and the multicarrier inverse orthogonal transformer and the single carrier inverse orthogonal transformer are used for both the single carrier transmission and the multicarrier transmission. It is characterized by being.

  Further, the present invention uses, as an input signal, an estimation result estimated by a propagation path estimation apparatus that estimates at least one of a propagation function of a propagation path, the received signal power, a distance between the radios, or a delay spread, A selection / setting device configured to select either the single carrier transmission or the multicarrier transmission, to select a modulation method, and to set a transmission signal power, and the selection / setting device includes a mode for the single carrier transmission or The mode for multi-carrier transmission is switched, and one or more types of PSK (Phase Shift Keying) modulation method and one or more types of QAM (Quadrature Amplitude Modulation) methods are adaptively adapted for each carrier or all carriers. Select an encoding method from two or more encoding methods And the transmission signal power is adaptively set.

  In addition, according to the present invention, when the one radio device transmits a signal, a pilot signal of a data signal sequence is inserted, and at least information on each of transmission mode, modulation scheme, and coding rate is inserted into the pilot signal. The other radio unit decodes the pilot signal when receiving the signal, and the decoded signal is used to decode at least the information related to the transmission mode, the modulation scheme, and the coding rate. One is extracted, and based on the extracted at least one, the mode is switched to the reception mode for single carrier transmission or the reception mode for multicarrier transmission, or the reception signal is decoded.

  Further, the present invention is characterized in that the one radio unit includes an error detection bit in a portion of the pilot signal in which at least one of the information on the transmission mode, the modulation scheme, or the coding rate is included. When the other radio receives a signal, an error occurs in the at least one of the information on the transmission mode, the modulation scheme, and the coding rate from the error detection bit. If the error occurs, the pilot signal is requested to be retransmitted.

  Also, the present invention provides an orthogonal transformer that converts a time-series signal into a frequency component when a single carrier signal is generated in the one radio device, and a signal that is converted into a frequency domain by the orthogonal transformer. And a weighting device that weights each frequency component, and an inverse orthogonal transformer that converts the signal weighted by the weighting device back into a time-series signal, and the weighting value of the weighting device is a band limiting filter. The frequency response value is set.

  In addition, the present invention includes transmission modes for both single carrier transmission and multicarrier transmission, and the reception signal power of the own radio device or both reception systems for single carrier transmission and multicarrier transmission. When a power reference value serving as a reference of received signal power of another radio having a transmission mode is defined in advance, and the received signal power of the own radio or the other radio is less than or equal to the power reference value Includes transmitting a signal using the single carrier transmission mode, and transmitting the signal using the multicarrier transmission mode when the received signal power is equal to or higher than the power reference value. .

  In addition, the present invention includes transmission modes for both single-carrier transmission and multi-carrier transmission, and other wireless devices having both single-carrier transmission and multi-carrier transmission modes. When a distance reference value serving as a reference for the distance between the two is preliminarily defined, and the distance estimated by the distance estimating means for estimating the distance to the other radio is greater than or equal to the distance reference value A signal is transmitted using the single carrier transmission mode, and a signal is transmitted using the multicarrier transmission mode when the distance estimated by the distance estimating means is equal to or less than the distance reference value. It is characterized by.

  In addition, the present invention includes transmission modes for both single-carrier transmission and multi-carrier transmission, and other wireless devices having both single-carrier transmission and multi-carrier transmission modes. A delay reference value serving as a reference for the delay spread between the other wireless devices is defined in advance, and the delay spread estimated by the propagation path estimating means for estimating the delay spread with the other radio device is equal to or less than the delay reference value. In this case, the signal is transmitted using the single carrier transmission mode, and when the delay spread estimated by the propagation path estimation means is equal to or larger than the delay reference value, the multicarrier transmission mode is used. And transmitting a signal.

  In addition, the present invention includes transmission modes for both single carrier transmission and multicarrier transmission, and a transmission power reference value serving as a reference for transmission signal power in the own radio device is defined in advance. A reception power reference value serving as a reference of reception signal power in another radio having both transmission modes of multi-carrier transmission is defined in advance, and the reception signal power is equal to or greater than the reception power reference value. As described above, when the other radio device requests transmission signal power, if the transmission signal power is more than the transmission power reference value, the signal is transmitted using the single carrier transmission mode. And when the said transmission signal power is below the said transmission power reference value, a signal is transmitted using the said multicarrier transmission mode, It is characterized by the above-mentioned.

According to the present invention, when the received signal power of the receiver is small, single carrier transmission with small PAPR can be used, and signal transmission superior to multicarrier transmission can be achieved even if the backoff is small to some extent. .
On the other hand, when the received signal power is large, multicarrier transmission can be used, and higher throughput can be obtained than single carrier transmission.

(Embodiment 1)
Hereinafter, the radio | wireless communications system in the 1st Embodiment of this invention is demonstrated with reference to drawings.
FIG. 1 shows a wireless communication system 1 as a first embodiment of the present invention.
The wireless communication system 1 includes a plurality of wireless devices A, B, C,..., N, a plurality of base stations (wireless devices) a, b, c,. ing.
A plurality of base stations a, b, c,..., M connect a plurality of wireless devices A, B, C,. It is installed on the telephone booth and the ceiling of the subway platform.
The communication network 2 is a network that interconnects a plurality of radio devices A, B, C,..., N, and is a telephone network, an IP network, a mobile network, or the like.

Since the configurations of the wireless devices A, B, C,..., N are almost the same, the wireless device A will be described here as a representative. The base stations a, b, c,..., M also have the same configuration as the wireless device A with respect to the transmission / reception function, and the base stations a, b, c,. It goes without saying that it can be a “machine”.
As shown in FIG. 2, the wireless device A includes a transmission unit (transmission circuit for multicarrier transmission) 10 for transmitting a signal and a reception unit (for single carrier transmission) for receiving a transmitted signal. Receiving circuit, multicarrier transmission receiving circuit) 12.
The transmission unit 10 includes an encoder 1001 that performs encoding, a modulator 1002 that performs PSK or QAM modulation, and a transmission mode changeover switch 1003 that performs switching. The transmission unit 10 includes a multicarrier transmission unit 16 that performs transmission using a multicarrier, and a single carrier transmission unit 15 that performs transmission using a single carrier. The transmission unit 10 also includes a transmission radio unit 1009 that performs various processes for transmission, and a transmission / reception antenna 1102.

The multicarrier transmission unit 16 includes a serial / parallel converter (serial / parallel converter circuit) 1004 that converts an input signal from serial to parallel, and an inverse orthogonal converter (for multicarrier) that performs inverse orthogonal transform on the input signal. An inverse orthogonal transformer) 1005, a GI insertion device 1006a for inserting a guard interval (GI), and a waveform shaping circuit 1007 for shaping a waveform in the multicarrier signal.
In addition, the single carrier transmission unit 15 includes a GI insertion device 1006b that inserts a GI, and a waveform shaping circuit 1008 that shapes the waveform of the single carrier signal.
That is, the wireless device A has transmission modes for both single carrier transmission and multicarrier transmission.

  On the other hand, the reception unit 12 includes the transmission / reception antenna 102 described above, a reception radio unit 1201 that performs various processes on a signal received by the transmission / reception antenna 102, and a GI removal device 1202 that removes the GI. The receiving unit 12 includes an orthogonal transformer (single carrier orthogonal transformer, multicarrier orthogonal transformer) 1203 that performs orthogonal transformation on an input signal, and a channel equalizer (weighting unit) that performs channel equalization. 1205 and a weight calculator (weighting control device) 1204 for calculating the channel equalization weight. In addition, the receiving unit 12 includes a transmission mode changeover switch 1206 that performs switching, a parallel / serial converter 1207 that converts an input signal from parallel to serial, and an inverse orthogonal transformer (single signal converter) that performs inverse orthogonal transformation on the input signal. Carrier inverse orthogonal transformer) 1208. Furthermore, the receiving unit 12 includes a determination value generation circuit 1209 that generates a soft decision value or a hard decision value, and a channel decoding circuit (single carrier demodulation circuit, multicarrier demodulation circuit, demodulation circuit) 1210 that performs decoding processing. I have.

  Radio A includes a propagation path estimation device (propagation path estimation means) 1101 connected to a weight calculator 1204 and an orthogonal transformer 1203. The propagation path estimation device 1101 estimates a propagation path between the wireless device A and another wireless device that performs communication (for example, the base station a), and receives the information from the estimated propagation path by the receiving unit 12. The received signal power value of the received signal is estimated. The propagation path estimation apparatus 1101 inputs the estimated propagation path information to the weight calculator 1204 and inputs the estimated received signal power value to the control unit 1300 described later.

The received signal power value is estimated as follows.
From another wireless device (base station a), a signal (pilot signal) known by the wireless device A is transmitted in advance, and the wireless device A takes a correlation value using the known signal for the received signal, Estimate propagation path information (impulse response). Alternatively, the data signal determined by the wireless device A can be fed back, the data signal can be regarded as the known signal, and the propagation path information can be estimated.
The transfer function is obtained by performing orthogonal transformation on the propagation path information (impulse response) obtained by the above-described estimation of propagation path information. Alternatively, the correlation between the signal obtained by performing orthogonal transformation on the signal received by the wireless device A by transmitting the signal of the known (pilot) signal from another wireless device and the known signal after the orthogonal transformation is obtained. By taking it, it is also possible to estimate the transfer function. Further, instead of the known signal, it is also possible to use the data signal after making a judgment feedback.

  Using the estimated propagation path information (impulse response) or its transfer function, taking the square of the absolute value for each estimated component and taking the sum (or average value) of the values, the received signal power value Can be estimated. Specifically, it is given by the following equation.

もしくは

Or

Here, {g (n)} is the estimated value of the impulse response of the propagation path, n is the delay index, {G (k)} is the estimated value of the channel transfer function, k is the orthogonal component index, and N is the estimated value. The number of responses, K, is the number of orthogonal components.
It is also possible to perform the above operation with another wireless device (base station a), transmit the information to the wireless device A using a pilot signal, and use the information. In addition, when the automatic reception gain control (AGC) is performed in the radio unit of the radio device A, the control voltage for controlling the AGC is uniquely determined according to the received signal power. It is also possible to estimate the received signal power value.

  In addition, the wireless device A includes a control unit (weighting control device, selection / setting device) 1300 connected to the propagation path estimation device 1101. The control unit 1300 includes a memory (not shown), and a power reference value serving as a reference for received signal power is stored in the memory.

Here, the power reference value is a criterion for transmission in either single carrier transmission or multicarrier transmission. For example, the power reference value is determined as follows.
From the propagation path environment information (impulse response or its transfer function) assumed by the wireless system, the relationship between the received signal power Pr and the transmission mode that achieves the maximum throughput can be obtained in advance by computer simulation. When Pr> Po, the multi-carrier transmission mode has a higher throughput, and when Pr ≦ Po, the single-carrier transmission mode is expected to have a higher throughput, Po is used as the power reference value.

  The power reference value determined in this way is stored in the memory in advance at the time of shipment. Alternatively, the base station or the like may appropriately calculate the power reference value and transmit it to each wireless device, and each wireless device may appropriately receive and store the power reference value in the memory.

  The control unit 1300 is connected to the weight calculator 1204 and the transmission mode changeover switches 1003 and 1206. The control unit 1300 reads the received signal power value estimated by the propagation path estimation apparatus 1101 and the power reference value stored in the memory, and determines the magnitude of these two values. Then, the control unit 1300 switches to single carrier transmission or multicarrier transmission in each of the transmission mode change-over switches 1003 and 1206 according to the determination result. Furthermore, the control unit 1300 inputs the magnitude determination result to the weight calculator 1204.

Next, processing of the wireless device A in the present embodiment configured as described above will be described.
Here, in order to simplify the description, a one-to-one communication between a pair of wireless devices A and B is considered.
First, the transmission process of the wireless device A will be described.
FIG. 3 is a flowchart showing a transmission process of the wireless device A.
First, the wireless device A performs transmission preparation processing (step S11). That is, when a transmission data sequence is input to encoder 1001, encoder 1001 performs encoding on the transmission data sequence. For the encoding, an error correction code such as a convolutional code, a turbo code, a trellis code, or an LDPC code can be used. The output of the encoder 1001 is input to the modulator 1002, and the modulator 1002 performs symbol modulation on the input signal.

Then, the control unit 1300 reads the received signal power value estimated by the propagation path estimation device 1101 and the power reference value stored in the memory. Then, the magnitude determination of these two values is performed (step S12).
If control unit 1300 determines that the received signal power value is greater than the power reference value (step S12: YES), control unit 1300 switches transmission mode switch 1003 to multicarrier transmission (step S13). That is, the control unit 1300 switches the transmission mode changeover switch 1003 to the terminal 1003 a connected to the multicarrier transmission unit 16.
Here, the propagation path estimation apparatus 1101 uses the pilot signal sequence transmitted from the wireless device B and inserted in the data sequence to obtain the correlation value between the received signal and the pilot signal, so that the wireless device A performs the wireless device A. And the radio channel B can be estimated in advance.
Further, using the pilot sequence inserted from the data sequence transmitted from the wireless device A, the propagation path between the wireless device A and the wireless device B is estimated in advance by the wireless device B, and the propagation path information is wirelessly transmitted. It is also possible to feed back to the machine A and use it.

  Further, the wireless device A performs transmission processing for multicarrier transmission (step S14). That is, the output from the modulator 1002 is input to the serial / parallel converter 1004 via the transmission mode changeover switch 1003. The serial / parallel converter 1004 performs serial / parallel conversion every N samples, and inputs the conversion result to the inverse orthogonal transformer 1005. The inverse orthogonal transformer 1005 performs inverse orthogonal transform on the input signal, and the GI insertion device 1006a inserts GI into the converted signal. Then, the waveform shaping circuit 1007 performs waveform shaping on the signal to generate a multicarrier transmission signal. Then, the transmission / reception antenna 1102 transmits a signal via the transmission radio unit 1009, and the process is terminated.

  On the other hand, when it is determined in step S12 that the received signal power value is smaller than the power reference value (step S12: NO), the control unit 1300 switches the transmission mode switch 1003 to single carrier transmission (step S15). ). That is, the control unit 1300 switches the transmission mode switch 1003 to the terminal 1003 b connected to the single carrier transmission unit 15. Then, the wireless device A performs a transmission process for single carrier transmission (step S16). That is, the output from the modulator 1002 is input to the GI insertion device 1006b via the transmission mode changeover switch 1003. The GI insertion device 1006b inserts a GI into the input signal, and the waveform shaping circuit 1008 performs waveform shaping on the signal to generate a single carrier transmission signal. Then, the transmission / reception antenna 1102 transmits a signal via the transmission radio unit 1009, and the process is terminated.

Next, the reception process of the wireless device A will be described.
FIG. 4 is a flowchart showing the reception process of the wireless device A.
First, when the transmission signal arrives, the wireless device A performs reception preparation processing (step S21). That is, the transmission / reception antenna 1102 receives a transmission signal. At this time, a pilot signal is received in advance from the wireless device a, and the pilot signal is input to the control unit 1300 after predetermined processing. This pilot signal includes information on whether to use the single carrier transmission mode or the multicarrier transmission mode.
When receiving the transmission signal, reception radio section 1201 converts the signal into a baseband digital signal. Then, the GI removal device 1202 removes the GI from the digital signal and inputs the removed signal to the orthogonal transformer 1203 every N samples. The orthogonal transformer 1203 performs orthogonal transformation on the input signal and inputs the result to the propagation path estimation apparatus 1101 and the channel equalizer 1205. The propagation path estimation apparatus 1101 estimates the propagation path between the wireless device A and the wireless device B and the received signal power value from the input signal by a predetermined arithmetic expression. Then, propagation path estimation apparatus 1101 inputs propagation path information to weight calculator 1204 and receives the received signal power value to control section 1300.

The control unit 1300 reads the pilot signal received in advance and determines whether the communication is in the single carrier transmission mode or the multicarrier transmission mode (step S22).
If it is determined that the multi-carrier transmission mode is set (step S22: YES), the control unit 1300 switches the transmission mode changeover switch 1206 for multi-carrier reception (step S23). That is, the transmission mode switch 1206 is switched to the terminal 1206a connected to the parallel / serial converter 1207. Then, the wireless device A performs reception processing for multicarrier transmission (step S24). That is, the control unit 1300 inputs the result of the size determination in step S22 to the weight calculator 1204. A weight calculator 1204 calculates a weight for multicarrier from a determination result from the control unit 1300 and propagation path information from the propagation path estimation apparatus 1101 using a predetermined arithmetic expression, and the calculation result is output to a channel or the like. The data is input to the generator 1205 and the determination value generation circuit 1209. The channel equalizer 1205 performs channel equalization on the input signal from the orthogonal transformer 1203 using the input weight.

  The channel equalizer 1205 performs multiplication of the received signal and the equalization weight at each frequency point. Note that the channel equalization weight includes a ZF (Zero Forcing) type, an MRC (Maximum Ratio Combining) type, an EGC (Equal Gain Combining) type, an MMSE (Minimum Mean Square Error) type, and the like.

  The output of the channel equalizer 1205 is input to the parallel / serial converter 1207 via the changeover switch 1206. The parallel / serial converter 1207 performs parallel / serial conversion on the input signal, generates a signal series, and inputs the signal series to the determination value generation circuit 1209. Then, the decision value generation circuit 1209 generates a soft decision value or a hard decision value based on the input signal series and the weight input from the weight calculator 1204, and inputs these values to the channel decoding circuit 1210. Further, channel decoding circuit 1210 performs error correction on the input signal to generate a transmission data sequence. This transmission data series is input to a predetermined processing unit, and the processing is completed.

  On the other hand, when determining in step S22 that the mode is the single carrier transmission mode (step S22: NO), the control unit 1300 switches the transmission mode changeover switch 1206 for single carrier reception (step S25). That is, the transmission mode switch 1206 is switched to the terminal 1206b connected to the inverse orthogonal transformer 1208. Then, the wireless device A performs a reception process for single carrier transmission (step S26). That is, the control unit 1300 inputs the result of the size determination in step S22 to the weight calculator 1204. A weight calculator 1204 calculates a weight for a single carrier from a determination result from the control unit 1300 and propagation path information from the propagation path estimation apparatus 1101 using a predetermined arithmetic expression, and the calculation result is output to a channel or the like. The data is input to the generator 1205 and the determination value generation circuit 1209. The channel equalizer 1205 performs channel equalization on the input signal from the orthogonal transformer 1203 using the input weight.

  The output of the channel equalizer 1205 is input to the inverse orthogonal transformer 1208 via the changeover switch 1206. The inverse orthogonal transformer 1208 performs inverse orthogonal transformation on the input signal to generate a signal sequence, and inputs the signal sequence to the determination value generation circuit 1209. Then, the decision value generation circuit 1209 generates a soft decision value or a hard decision value based on the input signal series and the weight input from the weight calculator 1204, and inputs these values to the channel decoding circuit 1210. Further, channel decoding circuit 1210 performs error correction on the input signal to generate a transmission data sequence. This transmission data series is input to a predetermined processing unit, and the processing is completed.

As described above, according to the wireless communication system 1 in the present embodiment, when the received signal power of the wireless device A is small, single carrier transmission with a small PAPR can be used, and multi-carrier transmission can be performed even if the backoff is somewhat small. In contrast, excellent signal transmission is possible. On the other hand, when the received signal power is large, multicarrier transmission can be used, and higher throughput can be obtained than single carrier transmission.
In addition, since the orthogonal transformer 1203 is also used for multicarrier transmission and single carrier transmission, the circuit configuration can be simplified and the circuit scale can be reduced.
Furthermore, by using the inverse orthogonal transformer 1005 and the inverse orthogonal transformer 1208 together, further simplification and miniaturization can be achieved.

(Embodiment 2)
Next, a second embodiment of the present invention will be described.
FIG. 5 shows a second embodiment of the present invention.
In FIG. 5, the same components as those shown in FIGS. 1 to 4 are denoted by the same reference numerals, and the description thereof is omitted.
This embodiment and the first embodiment have the same basic configuration, and only the differences will be described here.

In the present embodiment, the wireless device A includes a control unit (weighting control device, selection / setting device) 1300a for performing adaptive modulation. The control unit 1300a is connected to a modulation processing unit 20 having an encoder 1001 and a modulator 1002, and is connected to a decoding processing unit 21 having a determination value generation circuit 1209 and a channel decoding circuit 1210. The control unit 1300a is connected to the propagation path estimation device 1101.
The propagation path estimation apparatus 1101 determines the propagation function of the propagation path, the received signal power, the distance between the radio A and the radio B, or the delay from the information on the propagation path between the radio A and the radio B. Estimate one of the spreads.

These estimations are performed as follows.
The transfer function and received signal power can be estimated as described above.
Regarding the distance, the distance between the wireless device A and another wireless device is estimated using a device such as a global positioning system (GPS) that uses satellite communication or the like that is mounted in advance on the wireless device. .
The setting of the distance reference value is as follows.
In general, in line-of-sight signal transmission, it is known that the signal power is attenuated by r ^−α when the distance is r. Here, α is an attenuation multiplier. Therefore, in order to obtain the same reception power on the reception side, the radio signal A has to increase the transmission signal power as the distance increases. Therefore, for example, when a multicarrier signal is transmitted at a certain distance, the position where the maximum transmission power at which the signal is not distorted is set as the distance reference value, and when the distance is shorter than that, the multicarrier signal is transmitted. If it is long, a single carrier signal is transmitted. That is, the control unit 1300a compares the distance estimated by the global positioning system with a distance reference value that is defined and stored in advance, and determines that the distance is shorter, the control unit 1300a sets the transmission mode changeover switch 1003. Switch to multi-carrier transmission. On the other hand, when it is determined that the distance is longer, the control unit 1300a switches the transmission mode switch 1003 for single carrier transmission.

  For the distance reference value, when the attenuation multiplier α varies depending on the location, for example, when the base station is installed, the intensity of the surrounding radio waves is measured in advance, and the distance reference value is calculated based on the measured value. By storing the information in the memory in the base station, the transmission mode can be switched depending on the distance. When it can be assumed that the attenuation multiplier α does not vary depending on the location, the distance and the received power correspond one-to-one, and thus the distance reference value can be obtained from the above-described power reference value.

  Further, the delay spread T can be obtained by the following equation using the estimated propagation path information.

Here, τ (n) indicates a delay time in g (n) and is a value indicating how much time is delayed from g (1). Note that τ (1) is zero.
Further, the maximum delay time τ (N) can be used as a reference value, and if τ (N) is t or less, the single carrier transmission mode can be selected, and if it is t or more, the multicarrier transmission mode can be set.
The setting of the delay reference value is as follows.
If a certain delay spread T or τ (N) is exceeded, the transmission quality is significantly degraded in the single carrier transmission mode. Therefore, when the delay spread T exceeds the delay reference value T ₀ or when the estimated maximum delay time exceeds the delay reference value τ ₀ , the multicarrier transmission mode is selected. Here, the delay reference values T ₀ and τ ₀ can be determined from the relationship of transmission quality evaluated in advance by computer simulation.

  Under such a configuration, at the time of transmission, the control unit 1300a, for each carrier, based on the received signal power value input from the propagation path estimation device 1101 and the power reference value stored in advance in the memory, Or, like all carriers, the modulation scheme is adaptively changed from one or more PSK modulation schemes and one or more QAM schemes, and the coding rate is adaptively selected from two or more coding schemes. Change. As an encoding method, an error correction code such as a convolutional code, a turbo code, a trellis code, and an LDPC code can be used.

Note that the modulation scheme and coding rate are determined as follows.
After selecting the transmission mode using the estimated received signal power value or distance, the modulation scheme and coding rate are selected. Specifically, first, the control unit 1300a determines the estimated received signal power value or transmission mode, and then sets in advance on the basis of the received signal in the same manner as used in a conventional wireless LAN or the like. The modulation scheme and coding rate are determined using a table of combinations of modulation schemes and coding rates that can achieve the maximum throughput.
Also, when a signal is requested to be retransmitted when the received signal is not received correctly, the transmission mode is kept constant, and the multi-level number of one modulation scheme is lowered, or the coding rate is lowered and retransmitted. It is also possible to correctly determine the signal on the receiving side by performing.

  As described above, according to the wireless communication system 1 in the second embodiment, not only can the transmission mode be made variable, but also the modulation scheme and coding rate can be made variable, thereby enabling more flexible signal transmission. It becomes.

  At the time of transmission, transmission unit 10 may insert a pilot signal at the beginning of the transmission data sequence. The pilot signal includes information regarding transmission mode, modulation scheme, and coding rate indicating single carrier transmission or multicarrier transmission. Then, at the time of reception, the reception unit 12 decodes the pilot signal, and extracts each information related to the transmission mode, modulation scheme, and coding rate. Furthermore, the receiving unit 12 switches to a reception mode for single carrier transmission or a reception mode for multicarrier transmission based on the information regarding the extracted transmission mode. That is, the control unit 1300a switches the transmission mode changeover switch 1206. Furthermore, the receiving unit 12 decodes the signal based on the extracted information on the modulation scheme and the information on the coding rate. That is, based on the information on the modulation scheme and the information on the coding rate, the determination value generation circuit 1209 generates a soft decision value or a hard decision value, and the channel decoding circuit 1210 performs error correction and transmission. Generate a data series.

Further, at the time of transmission, the transmission unit 10 inserts error detection bits such as cyclic redundancy check (CRC) into a part of the pilot signal that includes information on the transmission mode, modulation scheme, and coding rate. May be. At the time of reception, the receiving unit 12 extracts error detection bits from the pilot signal. Furthermore, from the extracted error detection bits, the control unit 1300a determines whether an error has occurred in each information regarding the transmission mode, the modulation scheme, and the coding rate. When it is determined that an error has occurred, the control unit 1300a requests the wireless device B to retransmit the pilot signal.
Thereby, characteristic deterioration can be prevented.
In the above modification, all of the transmission mode, modulation scheme, and coding rate are inserted into the pilot signal. However, at least one of the transmission mode, modulation scheme, and coding rate may be inserted into the pilot signal. . When information on the transmission mode is inserted into the pilot signal, the transmission mode can be switched based on the extracted information on the transmission mode, and at least one of the information on the modulation scheme and coding rate is included in the pilot signal. When at least one of them is inserted, at least one of them can be changed adaptively.

(Embodiment 3)
Next, a third embodiment of the present invention will be described.
FIG. 6 shows a third embodiment of the present invention.
In FIG. 6, the same components as those shown in FIGS. 1 to 5 are denoted by the same reference numerals, and the description thereof is omitted.
This embodiment and the first embodiment have the same basic configuration, and only the differences will be described here.

The multicarrier transmission unit 16 in this embodiment includes a zero insertion device 3001 that inserts zeros into an input signal sequence. The zero insertion device 3001 is provided between the serial / parallel converter 1004 and the inverse orthogonal transformer 1005.
The single carrier transmission unit 15 includes an orthogonal transformer 3002 that converts a time-series signal into a frequency component, and a filter device (weighting device) 3003 for generating a single carrier signal.

With this configuration, in the case of multicarrier transmission, the serial / parallel converter 1004 performs serial / parallel conversion on the transmission symbol sequence, and then the zero insertion device 3001 inserts zeros on both sides of the signal spectrum. Then, an inverse orthogonal transformer 1005 performs an inverse orthogonal transform of N × m samples to obtain a multicarrier signal.
On the other hand, in the case of single-carrier transmission, after orthogonal transform 3002 performs N-sample orthogonal transform, filter device 3003 generates a single carrier signal using a band-limiting filter for a signal in which the orthogonal component is repeated m times. To do. That is, the filter device 3003 functions as a weighting device that weights each frequency component, and the weighting value is set to the frequency response value of the band limiting filter.
Further, similarly to the multicarrier transmission, the inverse orthogonal transformer 1005 performs an inverse orthogonal transform of N × m samples to obtain a single carrier time signal.

As described above, according to the wireless communication system 1 in the present embodiment, the convolution calculation that is necessary when performing waveform shaping (filtering) in the time domain is not required, and the amount of calculation can be reduced.
In the transmitter, the circuit scale can be reduced by sharing the inverse orthogonal transformer used in both the single carrier and multicarrier systems.

In the first to third embodiments, the number of wireless devices can be changed as appropriate, and it is sufficient that there is at least one pair.
In addition, although the power reference value of the received signal power is used as a reference for switching the transmission mode, the present invention is not limited to this, and a distance reference value that serves as a reference for the distance between one radio and another radio is used. It may be used. That is, when the wireless devices A, B, C,..., N include distance estimation means for estimating the distance using the global positioning system (GPS), for example, the wireless device A and the base station A distance reference value, which is a reference for the distance to a, is defined in advance. Then, the distance estimated by the distance estimating means is compared with a distance reference value defined and stored in advance, and when the control units 1300 and 1300a determine that the estimated distance is larger, single carrier transmission is performed. If the estimated distance is smaller, the signal is transmitted by multicarrier transmission.

  Here, the distance reference value is a reference for transmission in either single carrier transmission or multicarrier transmission. The determination of the distance reference value is as described above, and the description thereof is omitted here.

  In addition, as a reference for switching the transmission mode, a delay reference value serving as a reference for a delay spread between the wireless device A and the base station a can be used. That is, the propagation path estimation apparatus 1101 estimates the delay spread, compares the estimated delay spread with a predetermined delay reference value, and the control units 1300 and 1300a have a smaller estimated delay spread. If it is determined, the signal is transmitted by single carrier transmission, and if it is determined that the estimated delay spread is larger, the signal is transmitted by multicarrier transmission.

  Here, the delay reference value is a reference for determining whether transmission is performed in single carrier transmission or multicarrier transmission. The determination of the delay spread and the delay reference value is as described above, and the description thereof is omitted here.

  In addition, a reception power reference value that serves as a reference for reception signal power in the base station a may be defined in advance, and a transmission power reference value that serves as a reference for transmission signal power in the radio A may be defined in advance. Then, the base station a requests the transmission signal power from the wireless device A using a pilot signal or the like so that the reception signal power becomes the reception power reference value. On the other hand, when it is determined that the transmission signal power is required to be equal to or higher than the transmission power reference value, the radio A transmits a signal using the single carrier transmission mode and determines that the transmission power power may be equal to or lower than the transmission power reference value. In some cases, it is also possible to transmit signals using the multi-carrier transmission mode.

In addition, the said determination about transmission signal power is performed by the control parts 1300 and 1300a as follows.
From the propagation path environment information (impulse response or its transfer function) assumed by the wireless system, the relationship between the transmission signal power Pt and the transmission mode that achieves the maximum throughput can be obtained in advance by computer simulation. When Pt ≦ Ps, the multicarrier transmission mode has a high throughput, and when Pt> Ps, the single carrier transmission mode is expected to have a high throughput, Ps is used as a transmission power reference value.

In the above embodiment, orthogonal transform is performed. However, the present invention is not limited to this, and fast Fourier transform (FFT) or discrete Fourier transform (DFT) may be performed.
Moreover, in the said embodiment, although the same clock is assumed by multicarrier transmission and single carrier transmission, it is also possible to change the number of clocks by transmission mode.
In the above embodiment, the description is made assuming one-to-one communication. However, a combination of multiple access technologies such as antenna array technology, time division multiple access (TDMA) technology, and frequency division multiple access (FDMA) technology is combined. Therefore, it can be applied to one-to-many or many-to-many communication.
The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

1 is a system configuration diagram showing a first embodiment of a wireless communication system according to the present invention. FIG. 2 is a block diagram illustrating a configuration related to a transmission / reception function of the wireless device of FIG. 3 is a flowchart showing transmission processing of the wireless device of FIG. 3 is a flowchart showing reception processing of the wireless device of FIG. It is a figure which shows 2nd Embodiment of the radio | wireless communications system which concerns on this invention, Comprising: It is a block diagram which shows the structure regarding the transmission / reception function of a radio | wireless machine for every function. It is a figure which shows 3rd Embodiment of the radio | wireless communications system which concerns on this invention, Comprising: It is a block diagram which shows the structure regarding the transmission / reception function of a radio | wireless machine for every function. It is a block diagram which shows the conventional single carrier transmitter for every function. It is a block diagram which shows the conventional single carrier receiver for every function. It is a block diagram which shows the conventional multicarrier transmitter for every function. It is a block diagram which shows the conventional multicarrier receiver for every function.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wireless communication system 10 Transmitter (Transmission circuit for multicarrier transmission)
12 Receiver (Receiving circuit for single carrier transmission, receiving circuit for multicarrier transmission)
15 Single-carrier transmission unit 16 Multi-carrier transmission unit 1004 Series / parallel converter (series-parallel conversion circuit)
1005 Inverse orthogonal transformer (Inverse orthogonal transformer for multicarrier)
1101 Propagation path estimation device (propagation path estimation means)
1203 Orthogonal transformer (Orthogonal transformer for single carrier, Orthogonal transformer for multicarrier)
1204 Weight calculator (weight control device)
1205 Channel equalizer (weighting unit)
1208 Inverse orthogonal transformer (Inverse orthogonal transformer for single carrier)
1210 channel decoding circuit (single carrier demodulation circuit, multicarrier demodulation circuit, demodulation circuit)
1300, 1300a Control unit (weighting control device, selection / setting device)
3002 Orthogonal transformer 3003 Filter device (weighting device)
3004 Inverse orthogonal transformers A, B, C, ..., n

Claims (14)

In a wireless communication system composed of at least a pair of wireless devices,
One radio has transmission modes for both single carrier transmission and multicarrier transmission,
Other radios have transmission modes for both single-carrier transmission and multi-carrier transmission.
A power reference value serving as a reference of received signal power in the one or the other wireless device is defined in advance,
The one radio is
When the received signal power in the one or other radio device is less than or equal to the power reference value, a signal is transmitted using the single carrier transmission mode, and the received signal power is greater than or equal to the power reference value. In the case of transmitting a signal using the multi-carrier transmission mode,
The other radio is
When the one radio transmits a signal using the single carrier transmission mode, the signal is received using the single carrier transmission mode, and the one radio sets the multi carrier transmission mode. When a signal is transmitted using the wireless communication system, the signal is received using the multicarrier transmission mode. In a wireless communication system composed of at least a pair of wireless devices,
A distance estimating means for estimating a distance between one radio and another radio;
The one radio device includes transmission modes of both single carrier transmission and multicarrier transmission.
The other radio device has transmission modes for both single-carrier transmission and multi-carrier transmission.
A distance reference value that is a reference for the distance between the one wireless device and the other wireless device is defined in advance,
The one radio is
If the distance estimated by the distance estimating means is equal to or greater than the distance reference value, a signal is transmitted using the single carrier transmission mode, and the distance estimated by the distance estimating means is the distance reference If the value is less than or equal to the value, a signal is transmitted using the multicarrier transmission mode,
The other radio is
When the one radio transmits a signal using the single carrier transmission mode, the signal is received using the single carrier transmission mode, and the one radio sets the multi carrier transmission mode. When a signal is transmitted using the wireless communication system, the signal is received using the multicarrier transmission mode. In a wireless communication system composed of at least a pair of wireless devices,
Propagation path estimating means for estimating a delay spread between one radio and another radio,
The one radio device includes transmission modes of both single carrier transmission and multicarrier transmission.
The other radio device has transmission modes for both single-carrier transmission and multi-carrier transmission.
A delay reference value serving as a reference for a delay spread between the one radio and the other radio is defined in advance,
The one radio is
When the delay spread estimated by the propagation path estimation means is equal to or smaller than the delay reference value, a signal is transmitted using the single carrier transmission mode, and the delay spread estimated by the propagation path estimation means is When the delay reference value is equal to or greater than, the signal is transmitted using the multi-carrier transmission mode,
The other radio is
When the one radio transmits a signal using the single carrier transmission mode, the signal is received using the single carrier transmission mode, and the one radio sets the multi carrier transmission mode. When a signal is transmitted using the wireless communication system, the signal is received using the multicarrier transmission mode. In a wireless communication system composed of at least a pair of wireless devices,
One radio has transmission modes for both single carrier transmission and multicarrier transmission,
Other radios have transmission modes for both single-carrier transmission and multi-carrier transmission.
A reception power reference value that is a reference of reception signal power in the other wireless device is defined in advance,
A transmission power reference value serving as a reference of transmission signal power in the one radio device is defined in advance,
The other radio is
Requesting the transmission signal power to the one radio so that the reception signal power is equal to or higher than the reception power reference value,
The one radio is
When the transmission signal power is more than the transmission power reference value, a signal is transmitted using the single carrier transmission mode, and when the transmission signal power is less than or equal to the transmission power reference value, Send signal using carrier transmission mode,
The other radio is
When the one radio transmits a signal using the single carrier transmission mode, the signal is received using the single carrier transmission mode, and the one radio sets the multi carrier transmission mode. When a signal is transmitted using the wireless communication system, the signal is received using the multicarrier transmission mode. In the radio | wireless communications system as described in any one of Claims 1-4,
The other radio device includes a single-carrier transmission receiver circuit and a multi-carrier transmission receiver circuit,
The single carrier transmission receiving circuit is:
A single carrier orthogonal transformer that separates an input signal into a plurality of orthogonal frequency components;
A weighting unit for weighting each output of the single carrier orthogonal transformer;
An inverse orthogonal transformer that performs inverse orthogonal transformation on the signal weighted by the weighting unit;
A single carrier demodulating circuit for demodulating the output signal of the inverse orthogonal transformer;
A weighting control device for controlling a weighting value in the weighting device,
The multi-carrier transmission receiving circuit includes:
A multicarrier orthogonal transformer for separating an input signal into a plurality of orthogonal frequency components;
A multicarrier demodulation circuit that performs demodulation on each of the frequency components separated by the multicarrier orthogonal transformer,
The wireless communication system, wherein the single carrier orthogonal transformer and the multicarrier orthogonal transformer are used both for the single carrier transmission and for the multicarrier transmission. In the radio | wireless communications system as described in any one of Claims 1-4,
The at least one radio device includes a transmission circuit for multicarrier transmission and a reception circuit for single carrier transmission,
The multicarrier transmission circuit includes:
A serial-parallel conversion circuit for rearranging the input signal into a plurality of signal series;
An output of the serial-parallel conversion circuit as an input signal of each frequency component, and a multicarrier inverse orthogonal transformer that obtains a time-series signal by inverse orthogonal transformation,
The single carrier transmission receiving circuit is:
An orthogonal transformer that separates an input signal into a plurality of orthogonal frequency components;
A weighting unit for weighting each output of the orthogonal transformer;
An inverse orthogonal transformer for single carrier that performs inverse orthogonal transformation on the signal weighted by the weighting unit;
A demodulation circuit that demodulates the output signal of the single carrier inverse orthogonal transformer;
A weighting control device for controlling the weighting value in the weighting unit,
The wireless communication system, wherein the multicarrier inverse orthogonal transformer and the single carrier inverse orthogonal transformer are used for both the single carrier transmission and the multicarrier transmission. In the radio | wireless communications system as described in any one of Claims 1-4,
An estimation result estimated by a propagation path estimation device that estimates at least one of a transfer function of a propagation path, the received signal power, a distance between the radios, or a delay spread is used as an input signal, and the single carrier transmission or the A selection / setting device for selecting any of multicarrier transmission, selecting a modulation method, and setting transmission signal power,
The selection / setting device switches the mode for single carrier transmission or the mode for multicarrier transmission, and adaptively uses one or more PSK (Phase Shift Keying) modulation methods and one type for each carrier or all carriers. A radio communication system characterized by selecting a modulation scheme from the above QAM (Quadrature Amplitude Modulation) schemes, selecting a coding scheme from two or more types of coding schemes, and adaptively setting transmission signal power . In the radio | wireless communications system as described in any one of Claims 1-4,
The one radio is
When transmitting a signal, insert a pilot signal of a data signal sequence,
At least one of each information regarding transmission mode, modulation method or coding rate is added to the pilot signal,
The other radio is
Decoding the pilot signal when receiving the signal;
Extracting at least one of the respective information on the transmission mode, the modulation scheme and the coding rate from the decoded signal,
A radio communication system characterized by switching to a reception mode for single carrier transmission or a reception mode for multicarrier transmission or decoding a reception signal based on the extracted at least one. The wireless communication system according to claim 8,
The one radio is
In the pilot signal, an error detection bit is added to a part including at least one of the information related to the transmission mode, the modulation scheme, or the coding rate,
The other radio is
When receiving an signal, it is determined whether an error has occurred in at least one of the information related to the transmission mode, the modulation scheme, and the coding rate from the error detection bit, and an error has occurred. Includes a request for retransmission of the pilot signal. The wireless communication system according to any one of claims 1 to 9,
In the one radio device, when generating a single carrier signal, an orthogonal transformer that converts a time-series signal into a frequency component;
A weighting device for weighting each frequency component with respect to the signal transformed into the frequency domain by the orthogonal transformer;
An inverse orthogonal transformer that converts the signal weighted by the weighting device into a time-series signal again,
The wireless communication system, wherein the weighting value of the weighting device is set to a frequency response value of a band limiting filter. It has transmission modes for both single carrier transmission and multicarrier transmission.
The power reference value that serves as a reference for the received signal power of the own wireless device or the received signal power of other wireless devices having the transmission mode of both single carrier transmission and multicarrier transmission is predefined. ,
When the received signal power of the own radio device or the other radio device is less than or equal to the power reference value, a signal is transmitted using the single carrier transmission mode, and the received signal power is the power reference value. In the above case, the wireless device transmits a signal using the multicarrier transmission mode. It has transmission modes for both single carrier transmission and multicarrier transmission.
A distance reference value serving as a reference for the distance between other radios having transmission modes for both single carrier transmission and multicarrier transmission is defined in advance.
When the distance estimated by the distance estimating means for estimating the distance to the other radio is equal to or greater than the distance reference value, a signal is transmitted using the single carrier transmission mode, and the distance When the distance estimated by the estimation means is equal to or less than the distance reference value, a radio is transmitted using the multicarrier transmission mode. It has transmission modes for both single carrier transmission and multicarrier transmission.
A delay reference value serving as a reference for a delay spread with other radios having transmission modes for both single carrier transmission and multicarrier transmission is defined in advance.
If the delay spread estimated by the propagation path estimating means for estimating the delay spread with the other radio is equal to or less than the delay reference value, a signal is transmitted using the single carrier transmission mode, and When the delay spread estimated by the propagation path estimation means is greater than or equal to the delay reference value, a signal is transmitted using the multicarrier transmission mode. It has transmission modes for both single carrier transmission and multicarrier transmission.
A transmission power reference value that is a reference of transmission signal power in the own radio device is defined in advance,
A reception power reference value serving as a reference for received signal power in other radios having transmission modes for both single carrier transmission and multicarrier transmission is defined in advance.
When the other radio device requests transmission signal power so that the reception signal power is equal to or higher than the reception power reference value,
When the transmission signal power is more than the transmission power reference value, a signal is transmitted using the single carrier transmission mode, and when the transmission signal power is less than or equal to the transmission power reference value, A wireless device that transmits a signal using a carrier transmission mode.

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