WO2009154250A1 - Communication system, communication device, program, and communication method - Google Patents

Abstract

Provided is a communication system including a reception device and a first to a third transmission device.  The first transmission device and the second transmission device transmit a signal to the reception device while partially overlapping the frequency bands.  The third transmission device transmits a signal to the reception device by using a frequency band not used by the first or the second transmission device.

Description

COMMUNICATION SYSTEM, COMMUNICATION DEVICE, PROGRAM, AND COMMUNICATION METHOD

The present invention relates to a communication system, a communication device, a program, and a communication method.
This application claims priority based on Japanese Patent Application No. 2008-161648 filed in Japan on June 20, 2008, the contents of which are incorporated herein by reference.

In recent years, next-generation mobile communication systems have been studied, and a one-frequency repetitive cellular system has been proposed as a method for increasing the frequency utilization efficiency of the system. In this system, since each cell uses the same frequency band, each cell can use the entire band allocated to the system.
In the downlink, there is a high possibility that an OFDMA (Orthogonal Frequency Division Multiple Access) system will be adopted. The downlink is communication from the base station device to the mobile station device.

The OFDMA scheme performs communication by flexibly allocating radio resources among a plurality of mobile station apparatuses using OFDM signals that are subjected to communication by performing different modulations on information data according to reception conditions. For the modulation, 64-QAM (64-ary Quadrature Amplitude Modulation: 64-value quadrature amplitude modulation), BPSK (Binary Phase Shift Keying: two-phase modulation), or the like is used. The radio resource is composed of a time axis and a frequency axis.

In this case, since an OFDM signal is used, PAPR (Peak to Average Power Ratio) may be very high. In this case, high peak power does not pose a major problem in downlink communication where the transmission power amplification function has a relatively large margin. However, it becomes a fatal problem in the uplink where the transmission power amplification function has no margin. The uplink is communication from the mobile station device to the base station device.
Therefore, in the uplink, it is desirable to use a communication method based on a single carrier method with a low PAPR.

However, when the single carrier method is used, there is a problem that flexible resource allocation using the time axis and the frequency axis as in the OFDM method cannot be performed. SC-ASA (Single Carrier-Adaptive Spectrum Allocation: Single Carrier Adaptive Spectrum Allocation) and DFT-S-OFDM (Discrete Fourier Transform-Spread OFDM: DFT Spread OFDM) have been proposed as communication methods to solve this. For example, Non-Patent Document 1).

Since such a communication method uses the same method as the single carrier communication method, the peak-to-average power ratio (PAPR) is low. Moreover, it becomes possible to process data without inter-block interference by inserting a cyclic prefix like an OFDM signal. Hereinafter, an interval for inserting a cyclic prefix, that is, a data processing unit for performing Discrete Fourier Transform (DFT) is referred to as a “DFT-S-OFDM symbol”.
Furthermore, since the frequency waveform is once created by discrete Fourier transform (DFT), there is an advantage that resource control in units of subcarriers can be easily performed.

Furthermore, when this SC-ASA system is used in a plurality of transmission apparatuses, signals are arranged so as not to overlap on the frequency axis. Spectrum overlapping resource management (SORM: Spectrum-Overlapped Resource Management) that can improve transmission characteristics with the same amount of radio resources has been proposed (for example, Non-Patent Document 2). This technique is based on the assumption that nonlinear iterative equalization (hereinafter referred to as turbo equalization) having an interference suppression function is applied to a receiving apparatus, and the signal of each transmitting apparatus is changed to the frequency arrangement of the frequency signals of other transmitting apparatuses. Arrange freely. Then, regarding the overlapping frequency signals, mutual interference is suppressed by the interference suppression function of the receiving apparatus.

FIG. 13A is a schematic configuration diagram of a wireless communication system described in Non-Patent Document 2. FIG. 13B is a diagram illustrating a spectrum of a frequency signal transmitted from the first transmission device 100 a to the reception device 101. FIG. 13C is a diagram illustrating a spectrum of a frequency signal transmitted from the second transmitter 100b to the receiver 101. FIG. 13D is a diagram illustrating a spectrum of a frequency signal received by the reception apparatus 101 from the first transmission apparatus 100a and the second transmission apparatus 100b. In FIG. 13B to FIG. 13D, the horizontal axis indicates the frequency.
This wireless communication system includes a first transmission device 100a that is a mobile station device, a second transmission device 100b that is a mobile station device, and a reception device 101 that is a base station device.

The wireless communication system of FIG. 13A uses spectrum overlap resource management (SORM). When the first transmission device 100a and the second transmission device 100b transmit signals to the reception device 101, they are transmitted by overlapping some frequency signals. The reception apparatus 101 uses the interference suppression function to suppress interference, and as a result, performs transmission using a frequency with better reception conditions.
More specifically, the first transmission device 100a determines the first, second, fifth, and eighth frequency positions from a lower frequency to a higher frequency position arranged at regular intervals. In total, four frequency signals a11, a12, a13, and a14 are transmitted to the receiving apparatus 101. These frequency signals a11, a12, a13, and a14 change in amplitude and phase based on the propagation path characteristics and reach the receiving apparatus 101.

Similarly, the second transmission device 100b receives a total of four frequency signals a21, a22, a23, and a24 using the first, fifth, sixth, and seventh frequency positions. 101.
The receiving apparatus 101 receives a total of six frequency signals a31, a32, a33, a34, a35, a36 at the first, second, fifth, sixth, seventh, and eighth frequency positions. Receive.
However, at the first and fifth frequency positions, signals a31 and a33 obtained by combining the transmission signals of the first transmission device 100a and the second transmission device 100b in a propagation vector manner are received. In FIG. 13D, the spectra of the signals a31 and a33 are indicated by dotted lines.

FIG. 14 is a schematic block diagram showing a configuration of a conventionally known first transmission device 100a (FIG. 13A). Note that the configuration of the second transmission device 100b (FIG. 13A) is the same as that of the first transmission device 100a, and thus the description thereof is omitted.

The first transmission device 100a includes a coding unit 1001Z, an interleaving unit 1002Z, a modulation unit 1003Z, an S / P (Serial to Parallel: serial / parallel) conversion unit 1004Z, a DFT (Discrete Fourier Transform) unit 1005Z, a spectrum Mapping unit 1006Z, IDFT (Inverse DFT: Inverse Discrete Fourier Transform) unit 1007Z, P / S (Parallel to Serial) unit 1008Z, Pilot signal generation unit 1009Z, Pilot multiplexing unit 1010Z, CP (Cyclic Prefix) Click prefix) Insertion part 1011Z, D / A (Digital to Analog) conversion 1012Z, and includes a wireless unit 1013Z, the transmit antenna 1014Z.

Transmission data bits input to the first transmission device 100a are subjected to error correction encoding by the encoding unit 1001Z. The code data bits output from the encoding unit 1001Z are rearranged in order (time order) by the interleaving unit 1002Z. The interleaved code bits are mapped to signal points according to the modulation scheme by the modulation unit 1003Z, and a modulation signal is generated.
The modulated signal is converted from a serial signal to a parallel signal by the S / P converter 1004Z, and converted from a time signal to a frequency signal by the DFT unit 1005Z. Next, the frequency signal is spectrum-arranged based on spectrum allocation information notified from the receiving apparatus 101 (FIG. 13A) by the spectrum mapping unit 1006Z.

The arranged frequency signal is converted from a frequency signal to a time signal by the IDFT unit 1007Z. Then, the P / S converter 1008Z converts the parallel signal into a serial signal.
The pilot signal generation unit 1009Z generates a known pilot signal for estimating propagation path characteristics. This pilot signal is multiplexed with the serial signal obtained by P / S conversion section 1008Z and pilot multiplexing section 1010Z.

Thereafter, a cyclic prefix (CP) is inserted into the obtained signal by the CP insertion unit 1011Z. Then, the digital signal is converted into an analog signal by a D / A (Digital to Analog) converter 1012Z. Then, it is up-converted to a radio frequency by the radio unit 1013Z and transmitted from the transmission antenna 1014Z to the receiving apparatus 101 (FIG. 13A).

FIG. 15 is a schematic block diagram showing a configuration of a conventionally known receiving apparatus 101 (FIG. 13A).
Receiving apparatus 101 includes receiving antenna 2001Z, radio section 2002Z, A / D conversion section 2003Z, CP removal section 2004Z, pilot separation section 2005Z, propagation path estimation sections 2006Z-1 and 2006Z-2, scheduling section 2007Z, spectrum allocation information generation Unit 2008Z, buffer 2009Z, first S / P conversion unit 2010Z, first DFT unit 2011Z, spectrum demapping unit 2012Z, soft cancellation units 2013Z-1 and 2013Z-2, equalization units 2014Z-1 and 2014Z-2 , Demodulator 2015Z-1, 2015Z-2, deinterleaver 2016Z-1, 2016Z-2, decoder 2017Z-1, 2017Z-2, interleaver 2018Z-1, 2018Z-2, soft replica generator 2019Z-1, 2019Z- , Second S / P conversion units 2020Z-1 and 2020Z-2, second DFT units 2021Z-1 and 2021Z-2, interference extraction units 2022Z-1 and 2022Z-2, determination units 2024Z-1 and 2024Z-2 It has.

A reception signal received by the reception antenna 2001Z is down-converted to a baseband signal by the radio unit 2002Z. Then, the A / D converter 2003Z converts the analog signal into a digital signal.
The cyclic prefix (CP) is removed from the received signal converted into the digital signal by the CP removing unit 2004Z. And the pilot signal of each transmitter 100a, 100b is isolate | separated by the pilot separation part 2005Z.
With respect to the pilot signals from the separated transmission apparatuses 100a and 100b, the propagation path estimators 2006Z-1 and 2006Z-2 estimate the propagation path characteristics and the average received signal to noise ratio (SNR), respectively. The

The estimated propagation path characteristics are input to the soft cancellation units 2012Z-1 and 2013Z-2, the equalization units 2014Z-1 and 2014Z-2, and simultaneously input to the scheduling unit 2007Z. And the scheduling which determines the spectrum allocation which permitted the overlap of a part of spectrum is performed. Then, the determined spectrum allocation information is converted into a signal for feedback in the spectrum allocation information generation unit 2008Z, and transmitted to each of the transmission apparatuses 100a and 100b.
At the same time, in the next transmission opportunity, the spectrum demapping unit 2012Z stores the information as mapping information for returning the frequency signal to the buffer 2009Z.

On the other hand, the received signal of the data portion separated in pilot separation unit 2005Z is converted from a serial signal to a parallel signal by first S / P conversion unit 2010Z. Then, the first DFT unit 2011Z converts the time signal into a frequency signal.
For the obtained frequency signal, the spectrum demapping unit 2012Z extracts the mapping information obtained at the previous transmission opportunity from the buffer 2009Z, and separates the signals from the transmitting apparatuses 100a and 100b.

Here, at this stage, the frequency signal is simply restored using the mapping information. Therefore, some of the frequency signals that are duplicated at the time of transmission remain as interference with each other.
Next, the received signals from the transmitting apparatuses 100a and 100b returned to the original arrangement by the spectrum demapping unit 2012Z are input to the soft cancellation units 2013Z-1 and 2013Z-2. Then, in the soft cancellation units 2013Z-1 and 2013Z-2, replicas of the own signals obtained from the second DFT units 2021Z-1 and 2021Z-2 and the interference extraction units 2022Z-2 and 2022Z-1 and other The interference replica from the transmission apparatus is canceled and input to the equalization units 2014Z-1 and 2014Z-2.

Since the replica cannot be generated for the first time, nothing is canceled. The equalization units 2014Z-1 and 2014Z-2 perform equalization processing to compensate for signal distortion caused by the radio propagation path. The equalized signals are input to the demodulating units 2015Z-1 and 2015Z-2, and are decomposed into log likelihood ratios (LLRs) representing the reliability in units of code bits.
The log likelihood ratio (LLR) is expressed by the natural logarithm (the logarithm of e (Napier number) at the bottom) of the ratio of the probability that the sign bit is 1 and the probability that it is 0.

The obtained log likelihood ratio (LLR) is input to the deinterleaving sections 2016Z-1 and 2016Z-2 to restore the original interleaving sequence performed in the transmitting apparatus, and the decoding sections 2017Z-1 and 2017Z- 2 is input.
In decoding sections 2017Z-1 and 2017Z-2, error correction processing based on maximum a posteriori (MAP) estimation is performed, and an outer LLR of code bits and an a posteriori LLR of information bits with improved likelihood are output. The

Here, the external LLR represents the reliability improved only by the error correction process obtained by subtracting the LLR input from the a posteriori LLR of the sign bit. Since the external LLR is used for repetitive processing, it is input to the interleave units 2018Z-1 and 2018Z-2. Since the posterior LLR is used for determination of the transmission bit, it is input to the determination units 2024Z-1 and 2024-2Z.

First, the external LLR is input to the interleave units 2018Z-1 and 2018Z-2. Then, interleaving is performed in the same order as that of the transmission device, and input to the soft replica generation units 2019Z-1 and 2019Z-2 to generate a soft replica having an amplitude based on the reliability obtained from the external LLR.
The obtained soft replicas are input to equalization units 2014Z-1 and 2014Z-2 and also input to second S / P conversion units 2020Z-1 and 2020Z-2 for soft cancellation. Then, the second DFT units 2021Z-1 and 2021Z-2 convert the time signal into a frequency signal.

The obtained frequency signal is input to the soft cancellation units 2013Z-1 and 2013Z-2 in order to cancel the own signal. Further, the obtained frequency signal is input to the interference extraction units 2022Z-1 and 2022Z-2 in order to cancel the interference signal between the transmission apparatuses by the soft cancellation unit. Then, it is input to the soft cancel units 2013Z-2 and 2013Z-1, and the same processing is repeated again.
This process is repeated an arbitrary number of times or a predetermined number of times. Finally, the a posteriori LLR of the information bits obtained by the decoding units 2017Z-1 and 2017Z-2 is hard-determined by the determination units 2024Z-1 and 2024Z-2 to obtain decoded data.

Spectra overlap resource management (SORM) allows part of frequency signals from different transmitters to overlap. For this reason, the transmission characteristics are improved by leaving the overlapped band as a free band. However, there is a problem in that frequency utilization efficiency is not improved when a signal is transmitted from the transmission device to the reception device.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a communication system, a communication device, a program, and a communication method capable of transmitting a signal from a transmission device to a reception device with high frequency utilization efficiency. It is to provide.

(1) A communication system according to an aspect of the present invention is a communication system including a reception device and first to third transmission devices, and the first transmission device and the second transmission device are partially A signal is transmitted to the receiving device by overlapping frequency bands, and the third transmitting device transmits a signal to the receiving device using a frequency band that is not used by the first and second transmitting devices. To do.

(2) A communication system according to an aspect of the present invention is a communication system including a reception device and first to third transmission devices, and the third transmission device uses a predetermined frequency band. The first transmission device and the second transmission device transmit signals to the reception device by overlapping a part of the frequency band other than the predetermined frequency band.

(3) Further, in the communication system according to one aspect of the present invention, the frequency band used by the third transmission device is based on a frequency with a small sum of reception signal noise ratios of the first and second transmission devices. It may be determined.

(4) A communication system according to an aspect of the present invention is a communication system including a receiving device and first to third transmitting devices, and the third transmitting device uses a predetermined subchannel. The first transmitting apparatus and the second transmitting apparatus transmit signals to the receiving apparatus by overlapping a part of subchannels other than the predetermined subchannel.

(5) In the communication system according to the aspect of the present invention, the total transmission bandwidth of the subchannels used by the first transmission device and the second transmission device is the first transmission device and the second transmission. It may be larger than the transmission band to which the device signal can be allocated.

(6) In addition, the communication device according to one aspect of the present invention is a communication device that communicates with the first to third transmission devices, and the first transmission device has a frequency band that overlaps a part of the frequency bands. And a first allocating unit that allocates to the second transmitting device, and a second allocating unit that allocates frequency bands not allocated to the first and second transmitting devices to the third transmitting device.

(7) In addition, the program according to one aspect of the present invention provides a computer of a communication device that communicates with the first to third transmission devices with a frequency band obtained by overlapping a part of the frequency bands, A first allocating unit that allocates to the second transmitting apparatus, and a second allocating unit that allocates a frequency band not allocated to the first and second transmitting apparatuses to the third transmitting apparatus are caused to function.

(8) In addition, a communication method according to an aspect of the present invention is a communication using a first transmission device group including a plurality of transmission devices, a second transmission device group including at least one transmission device, and a reception device. A method of assigning a frequency band to each of the transmission devices of the first transmission device group so as not to overlap; a step of changing a part of the frequency band so as to overlap; A process of assigning non-overlapping frequency bands including a frequency band vacated by changing the overlapping to the transmitting apparatuses of the transmitting apparatus group, and each of the plurality of transmitting apparatuses constituting the first transmitting apparatus group, In the process of transmitting the frequency signal having the overlapped part of the frequency bands to the receiving device and the transmitting device configuring the second transmitting device group, each of the transmitting devices configuring the first transmitting device group includes: use Having the steps of transmitting a frequency signal to the reception apparatus using a frequency band not.

(9) In addition, a communication method according to an aspect of the present invention is a communication using a first transmission device group including a plurality of transmission devices, a second transmission device group including at least one transmission device, and a reception device. A method of assigning a frequency band to a transmission device of the second transmission device group, and a transmission device of the second transmission device group used for each of the transmission devices of the first transmission device group. And assigning the frequency band not to be partially overlapped to each other, and each of the plurality of transmitting apparatuses constituting the first transmitting apparatus group to the receiving apparatus In the transmission process, the transmission device constituting the second transmission device group uses the frequency band not used by each of the transmission devices constituting the first transmission device group to transmit the frequency signal to the reception device. And the process of sending A.

(10) In addition, a communication method according to an aspect of the present invention is a communication using a first transmission device group including a plurality of transmission devices, a second transmission device group including at least one transmission device, and a reception device. A method of dividing a frequency band into sub-channels for each frequency band of a predetermined width, a step of assigning one or a plurality of sub-channels to transmitting devices of the second transmitting device group, and the first Assigning to each of the transmission devices of the transmission device group one or more subchannels that are not used by the transmission device of the second transmission device group, so that some of the frequency bands overlap, Each of the plurality of transmission devices constituting the first transmission device group includes a process of transmitting a frequency signal in which a part of the frequency bands of the subchannel overlaps to the reception device, and the second transmission device group. You Transmitting device; and a process of transmitting a frequency signal to the reception apparatus using a frequency band of a sub-channel, each of the transmitting device is not used for forming the first transmission unit group.

The communication system, communication device, program, and communication method of the present invention can transmit a signal from a transmission device to a reception device with high frequency utilization efficiency.

1 is a schematic configuration diagram of a radio communication system according to a first embodiment of the present invention. It is a schematic block diagram which shows the structure of the 1st transmitter 11a by the 1st Embodiment of this invention. It is a schematic block diagram which shows the structure of the receiver 10 by the 1st Embodiment of this invention. It is a figure which shows frequency arrangement | positioning of the signal which the 1st transmitter 11a by the 1st Embodiment of this invention transmits to the receiver 10. FIG. It is a figure which shows frequency arrangement | positioning of the signal which the 2nd transmitter 11b by the 1st Embodiment of this invention transmits to the receiver 10. FIG. It is a figure which shows frequency arrangement | positioning of the signal which the 3rd transmitter 11c by the 1st Embodiment of this invention transmits to the receiver 10. FIG. It is a flowchart which shows the process of the receiver 10 by the 1st Embodiment of this invention. It is a figure which shows frequency arrangement | positioning of the signal which the 1st transmitter 11a by the 2nd Embodiment of this invention transmits to the receiver 10. FIG. It is a figure which shows the frequency arrangement | positioning of the signal which the 2nd transmitter 11b by the 2nd Embodiment of this invention transmits to the receiver 10. FIG. It is a figure which shows frequency arrangement | positioning of the signal which the 3rd transmitter 11c by the 2nd Embodiment of this invention transmits to the receiver 10. FIG. It is a flowchart which shows the process of the receiver 10 by the 2nd Embodiment of this invention. It is a figure which shows the frequency signal arrangement | positioning of the signal which the 1st transmitter 11a by the 3rd Embodiment of this invention transmits to the receiver 10. FIG. It is a figure which shows the frequency signal arrangement | positioning of the signal which the 2nd transmitter 11b by the 3rd Embodiment of this invention transmits to the receiver 10. FIG. It is a figure which shows the frequency signal arrangement | positioning of the signal which the 3rd transmitter 11c by the 3rd Embodiment of this invention transmits to the receiver 10. FIG. It is a flowchart which shows the process of the receiver 10 by the 3rd Embodiment of this invention. It is a table | surface which shows an example of the logical subcarrier number which the base station apparatus by the 4th Embodiment of this invention designates. It is a figure which shows an example of the mapping of the logical subcarrier number and physical subcarrier number by the 4th Embodiment of this invention. In the 4th Embodiment of this invention, it is a table | surface which shows an example of the physical subcarrier number which each user uses at time T3. 2 is a schematic configuration diagram of a wireless communication system described in Non-Patent Document 2. FIG. FIG. 4 is a diagram illustrating a spectrum of a frequency signal transmitted from the first transmission device 100a to the reception device 101. 6 is a diagram illustrating a spectrum of a frequency signal transmitted from the second transmission device 100b to the reception device 101. FIG. It is a figure which shows the spectrum of the frequency signal which the receiver 101 receives from the 1st transmitter 100a and the 2nd transmitter 100b. It is a schematic block diagram which shows the structure of the 1st transmitter 100a (FIG. 13A). It is a schematic block diagram which shows the structure of the receiver 101 (FIG. 13A).

Hereinafter, first to third embodiments of the present invention will be described with reference to the drawings. In the first to third embodiments, a case where single carrier adaptive spectrum allocation (SC-ASA scheme) is used will be described. And the case where a 1st transmitter and a 2nd transmitter transmit a signal to a receiver using spectrum duplication resource management (SORM) is demonstrated. A case will be described in which a frequency band is secured in order to multiplex signals from the third transmission apparatus.

[First Embodiment]
First, a first embodiment of the present invention will be described. In the present embodiment, frequency allocation by SORM is preferentially performed for the transmission apparatus 11a and the transmission apparatus 11b, and then the frequency allocation of the transmission apparatus 11c is performed in a band vacated by duplication.

FIG. 1 is a schematic configuration diagram of a wireless communication system according to a first embodiment of the present invention. The wireless communication system according to the present embodiment includes a first transmission device 11a that is a mobile station device, a second communication device 11b that is a mobile station device, a third communication device 11c that is a mobile station device, and a base station device. A receiving device 10 is provided.

In FIG. 1, a first transmission device 11a for performing communication using the spectrum overlapping resource management (SORM), the number of points of a discrete frequency which the second transmission device 11b is used as the N _u. Also, _let N _d be the number of discrete frequency points in the band that can be received by the receiving apparatus 10, that is, available. Also, let N _t be the number of discrete frequency points used by the third transmitter 11c.
Here, a case will be described in which N _d = 2N _u and the band secured by overlapping is N _t , but is not limited thereto. For example, when the spectrum overlap resource management (SORM) is used and 2N _t = N _u at the maximum, a quarter of the band corresponding to the number of points N _d is newly added to the third transmission device. 11c. Thereby, frequency utilization efficiency is greatly improved.
Further, here, a case where the bandwidths used by the first transmission device 11a and the second transmission device 11b are the same will be described, but the bandwidths used may be different.

In addition, when three transmission apparatuses having different bandwidths perform communication at the same time, the transmission apparatus having the narrowest bandwidth may be used as the third transmission apparatus.
In the embodiment described below, communication in the uplink, which is communication from the mobile station device to the base station device, will be described, but the present invention is not limited to this, and the base station device to the mobile station device is not limited thereto. You may use for the communication in the downlink which is communication.

In this embodiment, the case where three different transmission apparatuses 11a to 11c transmit different signals to the reception apparatus 10 will be described, but the present invention is not limited to this. For example, one transmission device may be equipped with three transmission antennas, and separate data may be transmitted to the reception device 10. Further, when two transmitting apparatuses communicate simultaneously, any one transmitting apparatus may be equipped with two transmitting antennas and transmit different data to the receiving apparatus 10.
Furthermore, although this embodiment demonstrates the case where the receiving apparatus 10 can grasp | ascertain the reception condition from all the transmission apparatuses, and determines the frequency arrangement | positioning in the receiving apparatus 10, it is not limited to this. For example, as long as the receiving device 10 can grasp the reception status, the frequency arrangement may be determined by another transmitting device or receiving device that is performing communication.

In the first embodiment, the number of points stochastically overlapping discrete frequency by spectrum Overlapped Resource Management (SORM) is N _t sample, assigning a signal of a third transmission device 11c to the band vacated by duplicate.

FIG. 2 is a schematic block diagram showing the configuration of the first transmission device 11a according to the first embodiment of the present invention. In addition, since the structure of the 2nd transmission apparatus 11b and the 3rd transmission apparatus 11c is the same as that of the 1st transmission apparatus 11a, those description is abbreviate | omitted.
The first transmission device 11a includes a coding unit 1001, an interleaving unit 1002, a modulation unit 1003, an S / P conversion unit 1004, a DFT unit 1005, a spectrum mapping unit 1006, an IDFT unit 1007, a P / S conversion unit 1008, and a pilot signal generator. Unit 1009, pilot multiplexing unit 1010, CP insertion unit 1011, D / A conversion unit 1012, radio unit 1013, and transmission antenna 1014.

The encoding unit 1001 receives transmission data bits.
Encoding section 1001 performs error correction encoding on the transmission data bits and outputs the result to interleaving section 1002.
Interleaving section 1002 performs interleaving processing for rearranging the bit order (time order) on the signal output from coding section 1001, and outputs the result to modulating section 1003.
Modulating section 1003 maps the signal output from interleaving section 1002 to a signal point corresponding to the modulation scheme, and generates a modulated signal.
S / P conversion unit 1004, a signal modulation unit 1003 outputs, from the serial signal is converted into parallel signals of _{N u} present, and outputs the DFT unit 1005.
The DFT unit 1005 converts the signal output from the S / P conversion unit 1004 from a time signal to a frequency signal and outputs the frequency signal to the spectrum mapping unit 1006.
Spectral mapping unit 1006, the signal DFT unit 1005 outputs, based on the spectrum allocation information notified from the receiving apparatus 10 performs the arrangement of the spectrum, as _{N d} of signal, and outputs the IDFT unit 1007.

The IDFT unit 1007 converts the signal output from the spectrum mapping unit 1006 from a frequency signal to a time signal and outputs the time signal to the P / S conversion unit 1008.
The P / S conversion unit 1008 converts the signal output from the IDFT unit 1007 from a parallel signal to a serial signal.
Pilot signal generation section 1009 generates a known pilot signal for estimating propagation path characteristics, and outputs the pilot signal to pilot multiplexing section 1010.
Pilot multiplexing section 1010 multiplexes the signal output from P / S conversion section 1008 and the signal output from pilot signal generation section 1009 and outputs the result to CP insertion section 1011.
CP insertion section 1011 inserts a cyclic prefix into the signal output from pilot multiplexing section 1010 and outputs the signal to D / A conversion section 1012.
The D / A conversion unit 1012 converts the signal output from the CP insertion unit 1011 from a digital signal to an analog signal and outputs the analog signal to the radio unit 1013.
The radio unit 1013 up-converts the signal output from the D / A conversion unit 1012 to a radio frequency, and transmits the radio frequency to the reception device 10.

FIG. 3 is a schematic block diagram showing the configuration of the receiving device 10 according to the first embodiment of the present invention. The reception apparatus 10 includes a propagation path estimation unit 31, a signal detection unit 32, a reception antenna 2001, a radio unit 2002, an A / D conversion unit 2003, a CP removal unit 2004, a pilot separation unit 2005, and propagation path estimation units 2006-1 and 2006. -2, scheduling unit 2007, spectrum allocation information generation unit 2008, buffer 2009, first S / P conversion unit 2010, first DFT unit 2011, spectrum demapping unit 2012, soft cancellation units 2013-1, 2013-2 , Equalization units 2014-1, 2014-2, demodulation units 2015-1, 2015-2, deinterleaving units 2016-1, 2016-2, decoding units 2017-1, 2017-2, interleaving units 2018-1, 2018 -2, soft replica generation unit 2019-1, 2019-2, second S / P conversion unit 020-1,2020-2, second DFT unit 2021-1,2021-2, interference extractor 2022-1,2022-2, and a determination unit 2024-1,2024-2.

The reception antenna 2001 receives signals transmitted from the first transmission device 11a, the second transmission device 11b, and the third transmission device 11c, and outputs the signals to the radio unit 2002.
Radio section 2002 down-converts the signal output from reception antenna 2001 into a baseband signal and outputs the result to A / D conversion section 2003.
The A / D conversion unit 2003 converts the signal output from the wireless unit 2002 from an analog signal to a digital signal and outputs the signal to the CP removal unit 2004.
CP removal section 2004 removes a cyclic prefix (CP) from the signal output from A / D conversion section 2003 and outputs the result to pilot separation section 2005.

The pilot separation unit 2005 separates the pilot signal of the third transmission device 11 c from the signal output from the CP removal unit 2004 and outputs the pilot signal to the propagation path estimation unit 31.
Pilot demultiplexing section 2005 demultiplexes the pilot signal of first transmission device 11a from the signal output from CP removal section 2004, and outputs it to propagation path estimation section 2006-1.
Further, pilot demultiplexing section 2005 demultiplexes the pilot signal of second transmission apparatus 11b from the signal output from CP removal section 2004, and outputs it to propagation path estimation section 2006-2.
Further, the pilot separation unit 2005 removes the pilot signal of the first transmission device 11a, the pilot signal of the second transmission device 11b, and the pilot signal of the third transmission device 11c from the signal output from the CP removal unit 2004. The signal is output to the first S / P converter 2010.

The propagation path estimation unit 31 estimates a propagation path characteristic and an average received signal noise ratio between the third transmission device 11c and the reception device 10 based on the pilot signal output from the pilot separation unit 2005, and performs signal detection. To the unit 32 and the scheduling unit 2007.
A propagation path estimation unit 2006-1 estimates a propagation path characteristic and an average received signal noise ratio between the first transmission device 11a and the reception device 10 based on the pilot signal output from the pilot separation unit 2005, The data is output to the soft cancellation unit 2013-1, the equalization unit 2014-1, and the scheduling unit 2007.
The propagation path estimation unit 2006-2 estimates the propagation path characteristics and the average received signal noise ratio between the second transmission device 11b and the reception device 10 based on the pilot signal output from the pilot separation unit 2005, The data is output to the soft cancellation unit 2013-2, the equalization unit 2014-2, and the scheduling unit 2007.
Note that the propagation path estimators 31, 2006-1, and 2006-2 may estimate the noise variance instead of estimating the average received signal-to-noise ratio.

The estimated propagation path characteristics are input to the soft cancellation units 2013-1, 2013-2 and equalization units 2014-1, 2014-2, and simultaneously to the scheduling unit 2007.
The scheduling unit 2007 performs scheduling for determining a spectrum allocation that allows some spectra to overlap. The scheduling unit 2007 outputs the determined spectrum allocation information to the spectrum allocation information generation unit 2008.
The spectrum allocation information generation unit 2008 converts the spectrum allocation information output from the scheduling unit 2007 into a signal for feedback to the first transmission device 11a, the second transmission device 11b, and the third transmission device 11c. Then, spectrum allocation information of the first transmission device 11a, spectrum allocation information of the second transmission device 11b, and spectrum allocation information of the third transmission device 11c are generated.
The spectrum allocation information generation unit 2008 transmits the spectrum allocation information of the first transmission device 11a, the spectrum allocation information of the second transmission device 11b, and the third transmission device 11c via a modulation unit, a radio unit, and a transmission antenna (not shown). Then, the data is transmitted to the first transmission device 11a, the second transmission device 11b, and the third transmission device 11c.
In addition, the spectrum allocation information generation unit 2008 uses the spectrum allocation information of the first transmission device 11a and the second transmission device 11b as mapping information for returning the frequency signal in the spectrum demapping unit 2012 at the next transmission opportunity. And the third transmission device 11c are stored in the buffer 2009.

Specifically, the spectrum allocation information generation unit 2008 of the receiving device 10 (also referred to as a communication device) of the present embodiment includes a first allocation unit 2008-1 and a second allocation unit 2008-2.
The first allocation unit 2008-1 allocates a frequency band obtained by overlapping a part of the frequency bands to the first transmission device 11a and the second transmission device 11b. The first allocation unit 2008-1 transmits the allocation information to the first transmission device 11a as spectrum allocation information of the first transmission device 11a and the second as spectrum allocation information of the second transmission device 11b. To the transmitter 11b.
The second allocation unit 2008-2 allocates a frequency band that is not allocated to the first transmission device 11a and the second transmission device 11b to the third transmission device 11c. The second allocation unit 2008-2 transmits the allocation information to the third transmission device 11c as spectrum allocation information of the third transmission device 11c.

The first S / P conversion unit 2010 converts the signal output from the pilot separation unit 2005 from a serial signal to a parallel signal, and outputs the parallel signal to the first DFT unit 2011.
The first DFT unit 2011 converts the signal output from the first S / P conversion unit 2010 from a time signal to a frequency signal and outputs the frequency signal to the spectrum demapping unit 2012.
The spectrum demapping unit 2012 reads the mapping information obtained at the previous transmission opportunity from the buffer 2009. Based on the read mapping information, the spectrum demapping unit 2012 determines whether the first transmission device 11a, the second transmission device 11b, and the third transmission device 11c are based on the signal output from the first DFT unit 2011. The transmitted signal is returned to the original arrangement and separated and output to the signal detection unit 32 and the soft cancellation units 2013-1 and 2013-2.
At this stage, since the frequency signal is simply restored using the mapping information, some of the frequency signals that were duplicated at the time of transmission remain as interference with each other.

Based on the signals output from the channel estimation unit 2006-1, the second DFT unit 2021-1, and the interference extraction unit 2022-2 from the signal output from the spectrum demapping unit 2012, the soft cancellation unit 2013-1 Cancel the replica of its own signal and the interference replica from other transmitters, and output them to the equalization unit 2014-1.
Further, soft cancellation section 2013-2 is based on signals output from propagation path estimation section 2006-2, second DFT section 2021-2, and interference extraction section 2022-1 from signals output from spectrum demapping section 2012. Thus, the replica of its own signal and the interference replica from another transmitting apparatus are canceled and output to the equalization unit 2014-2.
Since the replica cannot be generated in the first process, the soft cancellation units 2013-1 and 2013-2 do not perform the process of canceling the interference replica.

The equalization unit 2014-1 uses the signal output from the soft cancellation unit 2013-1, and based on the signal output from the channel estimation unit 2006-1 and the soft replica generation unit 2019-1, the signal distortion caused by the radio channel Is compensated for and output to the demodulator 2015-1.
The equalization unit 2014-2 uses the signal output from the soft cancellation unit 2013-2, based on the signal output from the propagation channel estimation unit 2006-2 and the soft replica generation unit 2019-2, to distort the signal due to the radio channel Is output to the demodulator 2015-2.

Demodulation section 2015-1 decomposes the signal output from equalization section 2014-1 into a log likelihood ratio (LLR) that represents the reliability in units of code bits, and outputs the result to deinterleaving section 2016-1.
Demodulation section 2015-2 decomposes the signal output from equalization section 2014-2 into a log likelihood ratio (LLR) representing reliability in units of code bits, and outputs the result to deinterleaving section 2016-2.
The log likelihood ratio (LLR) is expressed by the natural logarithm of the ratio of the probability that the sign bit is 1 and the probability that it is 0.

The deinterleaving unit 2016-1 performs deinterleaving processing for returning the arrangement (in time order) by the interleaving performed in the transmission device to the signal output from the demodulating unit 2015-1, and the decoding unit 2017-1 Output to.
The deinterleaving unit 2016-2 performs deinterleaving on the signal output from the demodulating unit 2015-2 to return the arrangement (in time order) due to the interleaving performed by the transmission device to the original, and the decoding unit 2017-2 Output to.

The decoding unit 2017-1 performs error correction processing based on the maximum posterior probability estimation for the signal output from the deinterleaving unit 2016-1, and obtains the outer LLR of the code bit and the posterior LLR of the information bit with improved likelihood. calculate. Decoding section 2017-1 outputs the external LLR to interleaving section 2018-1, and outputs the posterior LLR to determination section 2024-1.
The decoding unit 2017-2 performs error correction processing based on the maximum posterior probability estimation on the signal output from the deinterleaving unit 2016-2, and obtains the outer LLR of the code bit and the posterior LLR of the information bit with improved likelihood. calculate. Decoding section 2017-2 outputs the external LLR to interleaving section 2018-2, and outputs the posterior LLR to determination section 2024-2.
Here, the external LLR represents the reliability improved only by the error correction process obtained by subtracting the LLR input from the a posteriori LLR of the sign bit, and is used for the iterative process. The posterior LLR is used for transmission bit determination.

The interleaving unit 2018-1 performs the same interleaving process as the transmission apparatus on the external LLR output from the decoding unit 2017-1, and outputs the result to the soft replica generation unit 2019-1.
The interleaving unit 2018-2 performs the same interleaving process as the transmission apparatus on the external LLR output from the decoding unit 2017-2, and outputs the result to the soft replica generation unit 2019-2.

The soft replica generation unit 2019-1 generates a soft replica having an amplitude based on the reliability obtained from the external LLR based on the signal output from the interleaving unit 2018-1, and the equalization unit 2014-1, To the S / P converter 2020-1.
The soft replica generation unit 2019-2 generates a soft replica having an amplitude based on the reliability obtained from the external LLR based on the signal output from the interleaving unit 2018-2, and the equalization unit 2014-2, The data is output to the second S / P converter 2020-2.

The second DFT unit 2021-1 converts the signal output from the second S / P conversion unit 2020-1 from a time signal to a frequency signal. The second DFT unit 2021-1 outputs the converted signal to the soft cancel unit 2013-1 for canceling its own signal. The second DFT unit 2021-1 outputs the interference signal between the transmission apparatuses to the interference extraction unit 2022-1 so that the soft cancellation unit 2013-1 can cancel the interference signal.
The second DFT unit 2021-2 converts the signal output from the second S / P conversion unit 2020-2 from a time signal to a frequency signal. The second DFT unit 2021-2 outputs the converted signal to the soft cancel unit 2013-2 for canceling its own signal. The second DFT unit 2021-2 outputs the interference signal between the transmission apparatuses to the interference extraction unit 2022-2 so that the soft cancellation unit 2013-2 cancels the interference signal.

The soft cancel unit 2013-1 repeats the same process as the process described above. The soft cancel unit 2013-1 repeats this process an arbitrary number of times or a predetermined number of times. Finally, the determination unit 2024-1 generates decoded data by performing a hard determination on the a posteriori LLR of the information bits obtained by the decoding unit 2017-1.
The soft cancel unit 2013-2 repeats the same process as described above. The soft cancel unit 2013-2 repeats this process an arbitrary number of times or a predetermined number of times. Finally, the determination unit 2024-2 generates decoded data by performing a hard determination on the a posteriori LLR of the information bits obtained by the decoding unit 2017-2.

The propagation path estimation unit 31 estimates a propagation constant of a propagation path between the reception device 10 and the third transmission device 11c, and outputs the propagation constant to the signal detection unit 32 and the scheduling unit 2007.
The signal detection unit 32 detects the signal transmitted by the third transmission device 11c from the signal output by the spectrum demapping unit 2012.
The signal transmitted from the first transmission device 11a and the second transmission device 11b is not superimposed on the signal transmitted by the third transmission device 11c. Therefore, it is completely separated by the spectrum demapping unit 2012 and output to the signal detection unit 32.

FIG. 4A is a diagram illustrating a frequency arrangement of signals transmitted from the first transmission device 11a to the reception device 10 according to the first embodiment of the present invention.
FIG. 4B is a diagram illustrating a frequency arrangement of signals transmitted from the second transmission device 11b to the reception device 10 according to the first embodiment of the present invention.
FIG. 4C is a diagram illustrating a frequency arrangement of signals transmitted from the third transmission device 11c to the reception device 10 according to the first embodiment of the present invention.
4A to 4C, the horizontal axis represents the frequency.

As shown in FIG. 4A, the first transmitter 11a determines the first, second, fifth, sixth, eighth, ninth, tenth, and fourteenth frequency positions. In total, eight frequency signals b11, b12, b13, b14, b15, b16, b17, and b18 are transmitted to the receiving apparatus 10.
Also, as shown in FIG. 4B, the second transmitter 11b has the first, fifth, sixth, seventh, ninth, tenth, eleventh, and twelfth frequencies. A total of eight frequency signals b21, b22, b23, b24, b25, b26, b27, b28 are transmitted to the receiving apparatus 10 using the position.
Further, as illustrated in FIG. 4C, the third transmission device 11c uses the third, fourth, and thirteenth frequency positions to receive a total of three frequency signals b31, b32, and b33. Is sending to.

In the present embodiment, applying the first transmission device 11a and the spectral overlap Resource Management over N _d samples is bandwidth capable of transmitting signals of a second transmission device 11b (SORM).
Next, from the allocated band, the receiving apparatus 10 uses the remaining free band for the third transmitting apparatus 11c after the allocation of the discrete frequencies for the signals of the first transmitting apparatus 11a and the second transmitting apparatus 11b. Assign as bandwidth.
In this case, the number of samples N _t allocated to the signal of the third transmission device 11c depends on the frequency allocation for the signals of the first transmission device 11a and the second transmission device 11b, and thus changes for each transmission opportunity. There is no deterioration of characteristics.

FIG. 5 is a flowchart showing processing of the receiving device 10 according to the first embodiment of the present invention. First, the first allocation unit 2008-1 of the reception device 10 allocates discrete frequencies to the first transmission device 11a and the second transmission device 11b by using spectrum overlapping resource management (SORM) (step S1). S1).
Next, the second assigning unit 2008-2 of the receiving device 10 uses the discrete frequency that has not been assigned to either the first transmitting device 11a or the second transmitting device 11b as the frequency of the third transmitting device 11c. The assignment is determined (step S2).

More specifically, in the first embodiment of the present invention, the frequency band is not overlapped in each of the transmission devices of the first transmission device group including the reception device 10 and the plurality of transmission devices 11a and 11b. Allocation and change so that part of the frequency band overlaps (corresponding to step S1 in FIG. 5).
Then, a non-overlapping frequency band including a frequency band that has been vacated as a result of being changed so as to overlap is allocated to the transmitting apparatuses of the second transmitting apparatus group including at least one transmitting apparatus 11c (corresponding to step S2 in FIG. 5) .
Then, each of the plurality of transmission devices 11 a and 11 b configuring the first transmission device group transmits a frequency signal having a partial frequency band overlapping to the reception device 10. In addition, the transmission device 11c configuring the second transmission device group transmits a frequency signal to the reception device 10 using a frequency band that is not used by each of the transmission devices 11a and 11b configuring the first transmission device group. Send.

As described above, in the first embodiment of the present invention, the first transmission device 11a and the second transmission device 11b transmit signals to the reception device 10 by overlapping some frequency bands. The third transmission device 11c transmits a signal to the reception device 10 using a frequency band that is not used by the first transmission device 11a and the second transmission device 11b.
In this embodiment, since the first transmission device 11a and the second transmission device 11b are preferentially assigned, transmission from the transmission device to the reception device can be performed while maximizing the transmission characteristics of spectrum overlap resource management (SORM). The amount of information can be increased.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. This embodiment demonstrates the transmitter which performs the multiplexing using spectrum overlap resource management (SORM). Then, for the purpose of stably securing the signal transmission band of the third transmitting apparatus, a method for securing N _t samples of a frequency that has a high probability of not being assigned by spectrum overlap resource management (SORM) will be described.
The configuration of the wireless communication system according to the present embodiment, the configuration of the first to third transmission devices, and the configuration of the receiving device are the same as the configuration of the wireless communication system according to the first embodiment (except for the configuration of the scheduling unit 2007). Since the configuration of FIG. 1), the configuration of the first to third transmission devices 11a to 11c (FIG. 2), and the configuration of the reception device 10 (FIG. 3) are the same, the description of similar parts is omitted.

6A to 6C are diagrams illustrating frequency arrangements of signals transmitted from the transmission apparatuses 11a to 11c to the reception apparatus 10 according to the second embodiment of the present invention. 6A to 6C, the horizontal axis represents the frequency.
In FIG. 6A and FIG. 6B, the number of points of the overlapping spectrum in the spectrum overlapping resource management (SORM) is 5, but this figure shows only the concept.

FIG. 6A shows the frequency allocation assigned by spectrum overlap resource management (SORM) in the first transmission device 11a.
FIG. 6B shows the frequency allocation assigned by spectrum overlap resource management (SORM) in the second transmitter 11b.
FIG. 6C shows a frequency arrangement of the third transmission device 11c that is allocated while securing a frequency of N _t samples including a band vacated by spectrum overlap resource management (SORM).

That is, in FIG. 6A, the first transmission device 11a has the first, second, fifth, sixth, first, and lower frequency frequencies arranged at regular intervals from the lower frequency to the higher frequency. A total of eight frequency signals c11, c12, c13, c14, c15, c16, c17, and c18 are transmitted to the receiving apparatus 10 using the eighth, ninth, tenth, and fourteenth frequency positions. . These frequency signals c11 to c18 reach the receiving apparatus 10 with the amplitude and phase changed based on the propagation path characteristics.

In FIG. 6B, the second transmission device 11b has the first, second, fifth, sixth, seventh from the lower frequency to the higher frequency positions arranged at regular intervals. A total of eight frequency signals c21, c22, c23, c24, c25, c26, c27, c28 are transmitted using the ninth, tenth, and eleventh frequency positions. These frequency signals c21 to c28 reach the receiving apparatus 10 with the amplitude and phase changed based on the propagation path characteristics.

In FIG. 6C, the third transmission device 11c changes the third, fourth, twelfth, and thirteenth frequency positions from the lower frequency to the higher frequency positions arranged at regular intervals. In total, four frequency signals c31, c32, c33, c34 are transmitted. These frequency signals c31 to c34 reach the receiving apparatus 10 with the amplitude and phase changed based on the propagation path characteristics.

Here, the N _t samples required by the third transmitter 11c could not be secured, including the band vacated by the spectrum overlap resource management (SORM) for the first transmitter 11a and the second transmitter 11b. Shows the case. That is, the third transmitter 11c wants to use the twelfth frequency position having good propagation path characteristics for the transmitter, but the frequency position is already used by the second transmitter 11b.
If it can be ensured, it can be left as it is, but this embodiment performs the following processing when it cannot be ensured considering that the proportion of the overlapping spectrum is probabilistic. That is, processing is performed to ensure that degradation of reception quality of signals from the first transmitter 11a and the second transmitter 11b in spectrum overlap resource management (SORM) is minimized.

Further, as illustrated in FIG. 6B, the second transmission device 11b does not use the discrete spectrum of the frequency signal c20 (the 12th frequency position), and uses the discrete spectrum that is not used by the other third transmission device 11c. Use. Here, as a result, the second transmitter 11b uses the frequency signal c21 (second frequency position).
As a result, the signal N _t sample from the third transmission device 11c can be secured without significantly degrading the transmission characteristics of the signals from the first transmission device 11a and the second transmission device 11b. In addition, a throughput of 1 + N _t / N _d times the available frequency can be obtained.

Next, processing for securing the frequency of N _t samples will be described. Here, a case will be described in which the scheduling unit 2007 (FIG. 3) of the receiving apparatus 10 grasps the band N _t samples. First, to measure the spectral overlap Resource Management (SORM), the received SNR of _{N d} samples of the first transmission device 11a and the second transmission device 11b, respectively. Therefore, the receiving device 10 calculates the sum of received SNR expressed in decibels for each discrete frequency.
The receiving device 10 sorts (reorders) the received SNR of the transmitting device in ascending order. The received SNRs from the transmitters 11a and 11b at the k-th discrete frequency are S ₁ (k) and S ₂ (k), respectively. Using Equation (1), the total received SNR of each discrete frequency is calculated.

In equation (1), S (k) is the average received signal-to-noise ratio (SNR) of the sum of the discrete frequencies. Although the case where the average received signal-to-noise ratio (SNR) is expressed in decibels is described here, the present invention is not limited to this. Since it is only necessary to know the magnitude relationship of the overall discrete frequencies of the first transmission device 11a and the second transmission device 11b at each discrete frequency, the same processing can be performed even with a true value.
In addition, since the determination is made as to whether or not the reception status is inferior, it is possible to use an index and an operation such that the other reception indexes are sorted in the order of overall poor reception status.

For the discrete frequency of N _t samples in order from the worst in Equation (1), the discrete frequency is removed from the selectable frequencies by spectrum overlap resource management (SORM). Alternatively, even if an unreasonably low received SNR (for example, S ₁ (k) = S ₂ (k) = − 100 (dB), etc.) is assigned to a poor discrete frequency of N _t samples because it is not necessary to select it. good.

Discrete frequencies for transmitting the signals of the first transmission device 11a and the second transmission device 11b are set for the selectable discrete frequencies thus obtained based on spectrum overlap resource management (SORM). And the receiver 10 sets so that the signal of the 3rd transmitter 11c may be arrange | positioned with respect to the discrete frequency remove | deviated from the selectable discrete frequency.
Here, regarding the discrete frequencies with which the signals of the first transmitter 11a and the second transmitter 11b overlap, the discrete frequencies used autonomously by the first transmitter 11a and the second transmitter 11b are set. This is set probabilistically. Each transmitting apparatus does not grasp that it overlaps with other transmitting apparatuses, but only the receiving apparatus grasps and is separated by turbo equalization technology.
When an unreasonably low received SNR is assigned so as not to be selected, the signal arrangement of the third transmitter 11c is unreasonably low when assigning to the first transmitter 11a and the second transmitter 11b. The received SNR is allocated to the discrete frequency.

FIG. 7 is a flowchart showing processing of the receiving device 10 according to the second embodiment of the present invention. Here, the first allocation unit 2008-1 of the reception device 10 determines the discrete frequencies used for transmission by the first transmission device 11a and the second transmission device 11b using spectrum overlap resource management (SORM). To do. First, the first allocation unit 2008-1 measures the reception SNR of the signals from the first transmission device 11a and the second transmission device 11b for each discrete frequency, and calculates the sum for each discrete frequency ( Step S11).

Next, the first assigning unit 2008-1 of the receiving apparatus 10 sorts the sums of received SNRs in ascending order (step S12). Then, the first assigning unit 2008-1 removes the upper N _t samples from the candidates for discrete frequencies that can be selected by spectrum overlapping resource management (SORM) (step S13).
Next, the first allocation unit 2008-1 of the reception device 10 determines the frequency arrangement of the signal of the first transmission device 11a and the signal of the second transmission device 11b using the selectable discrete frequencies ( Step S14). Then, the second allocation unit 2008-2 of the reception apparatus 10 arranges the discrete frequency that is out of the selectable discrete frequencies in the spectrum overlap resource management (SORM) in the signal of the third transmission apparatus 11c (step S15). ).

More specifically, in the second embodiment of the present invention, a frequency band is assigned to a transmission device of the second transmission device group including at least one transmission device 11c (corresponding to step S15 in FIG. 7).
Further, a frequency band that is not used by the transmission device 11c of the second transmission device group is assigned to each of the transmission devices of the first transmission device group including the plurality of transmission devices 11a and 11b so as to partially overlap ( Equivalent to step S14 in FIG. 7).
Then, each of the plurality of transmission devices 11 a and 11 b configuring the first transmission device group transmits a frequency signal having a partial frequency band overlapping to the reception device 10.
Then, the transmission device 11c constituting the second transmission device group sends a frequency signal to the reception device 10 using the frequency band not used by each of the transmission devices 11a and 11b constituting the first transmission device group. Send.

In the second embodiment of the present invention, the third transmission device 11c transmits a signal to the reception device 10 using a predetermined frequency band. In addition, the first transmission device 11a and the second transmission device 11b transmit signals to the reception device 10 by overlapping a part of frequency bands other than the predetermined frequency band used by the third transmission device 11c.
In this embodiment, in order to arrange a signal from the third transmission device 11c, scheduling of spectrum overlap resource management (SORM) in the first transmission device 11a and the second transmission device 11b is limited. Thereby, more data can be multiplexed without expanding the frequency band. Moreover, since priority is given to ensuring the frequency with respect to the 3rd transmitter 11c, the transmission rate of the 3rd transmitter 11c can be compensated.

Here, in order to minimize the degradation of transmission characteristics due to spectrum overlap resource management (SORM), the signals of the first transmission device 11a and the second transmission device 11b are prioritized, but this is not limitative. Is not to be done. In order to prioritize the signal reception status of the third transmission device 11c, N _t samples are selected in order from the signal reception status of the third transmission device 11c in the order of good reception, and the rest is spectrum overlap resource management ( A discrete frequency selectable in (SORM) may be used.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. In the present embodiment, a case will be described in which the band to be allocated to the third transmission device 11c is subchannelized.
The configuration of the wireless communication system according to the present embodiment, the configuration of the first to third transmission devices, and the configuration of the receiving device are the same as the configuration of the wireless communication system according to the first embodiment (except for the configuration of the scheduling unit 2007). Since the configuration of FIG. 1), the configuration of the first to third transmission devices 11a to 11c (FIG. 2), and the configuration of the reception device 10 (FIG. 3) are the same, the description of similar parts is omitted.

8A to 8C are diagrams illustrating frequency arrangements of signals transmitted from the transmission apparatuses 11a to 11c to the reception apparatus 10 according to the third embodiment of the present invention.
FIG. 8A is a diagram showing a frequency signal arrangement of signals transmitted from the first transmission device 11a to the reception device 10 according to the third embodiment of the present invention.
FIG. 8B is a diagram showing a frequency signal arrangement of signals transmitted from the second transmission device 11b to the reception device 10 according to the third embodiment of the present invention.
FIG. 8C is a diagram showing a frequency signal arrangement of signals transmitted from the third transmission device 11c to the reception device 10 according to the third embodiment of the present invention.
That is, in FIG. 8A to FIG. 8C, four subchannels Sc1 to Sc4 are arranged from the lower frequency to the higher frequency. Each channel has four frequency positions. As shown in FIG. 8A, the first transmission device 11a uses the signals d11 and d12 at the first and second frequency positions from the lower frequency to the higher frequency in the subchannel Sc1, and uses the subchannel Sc2 , The signals d13, d14 and d15 at the first, second and third frequency positions are used, and the signals d16, d17 at the first, third and fourth frequency positions in the subchannel Sc3. A total of eight frequency signals are transmitted to the receiving apparatus 10 using d18. These frequency signals d11 to d18 change their amplitude and phase based on the propagation path characteristics and reach the receiving apparatus 10.

As shown in FIG. 8B, the second transmitter 11b uses the signals d21, d22, d23, and d24 at the first, second, third, and fourth frequency positions in the subchannel Sc1, In subchannel Sc2, signals d25 and d26 of the third and fourth frequency positions are used, and in subchannel Sc3, a total of eight signals are used using signals d27 and d28 of the second and third frequency positions. The frequency signal is transmitted to the receiving device 10. These frequency signals d21 to d28 change their amplitude and phase based on the propagation path characteristics and reach the receiving apparatus 10.
That is, the transmission signals transmitted by the first transmitter 11a and the second transmitter 11b are the first and second frequency positions of the subchannel Sc1, the third frequency position of the subchannel Sc2, and the subchannel. There are overlaps at a total of four frequency positions of the third frequency position of Sc3.
As illustrated in FIG. 8C, the third transmission device 11c transmits a total of four frequency signals using the signals d31, d32, d33, and d34 at all frequency positions in the subchannel Sc4. These frequency signals d31 to d34 reach the receiving apparatus 10 with the amplitude and phase changed based on the propagation path characteristics.

8A to 8C, subchannels Sc1 to Sc4 exist, and the total number of samples of the signal of the first transmission device 11a and the frequency signal of the second transmission device 11b is the sum of all of the subchannels Sc1 to Sc4. Equal to the total number of frequency points. Then, spectrum overlap resource management (SORM) is applied across the subchannels Sc1 to Sc3. The signal used by the third transmission device 11c is arranged in the subchannel Sc4.

First, the first transmission device 11a and the second transmission device 11b select subchannels for applying spectrum overlap resource management (SORM) so that a total of N _t samples of discrete frequencies remain in the best order. Here, if the discrete frequency point of one subchannel is _Nc , the subchannel is selected so that the relationship of Expression (2) is established.

Here, m is the number of subchannels for spectrum overlap resource management (SORM). N is the minimum number of subchannels for securing a discrete frequency of N _t samples.
That is, spectrum overlap resource management (SORM) is applied at discrete frequencies of mN _c samples while satisfying N _d = 2N _u .
At this time, priority may be given to the signal reception status of the third transmission device 11c, and a subchannel for securing a minimum of N _t samples may be determined first.

FIG. 9 is a flowchart showing processing of the receiving device 10 according to the third embodiment of the present invention. First, the first allocation unit 2008-1 of the receiving device 10 calculates the sum of the received SNRs for each subchannel of the first transmitting device 11a and the second transmitting device 11b (step S21). Here, in the second embodiment, the sum of received SNRs is calculated for each discrete frequency. However, when calculating for each subchannel, the sum of received SNRs of discrete frequencies included in the same subchannel is calculated. .

Next, the first allocation unit 2008-1 of the receiving apparatus 10 sorts the received SNR in descending order (step S22). Then, first allocation section 2008-1 sets subchannels having higher received SNRs as subchannels to which spectrum overlapping resource management (SORM) is applied, for the maximum number of subchannels remaining for N _t samples or more ( Step S23). Then, the first allocation unit 2008-1 applies spectrum overlap resource management (SORM) with the discrete frequencies included in the selected subchannel as selectable frequencies, and the first transmitter 11a and the second transmitter The frequency arrangement of the signal of the transmission device 11b is set (step S24).

Next, the second allocation unit 2008-2 of the reception device 10 allocates the signal of the third transmission device 11c to the subchannel not selected in Step S23 (Step S25). Here, regarding the signal arrangement of the third transmission device 11c in step S25, a method such as dynamic spectrum control that allocates a discrete frequency with a good reception condition may be used as long as it is greater than the discrete frequency of N _t samples. May be assigned continuously.

In the third embodiment of the present invention, the frequency band is divided into sub-channels for each frequency band of a predetermined width, and one or more sub-channels are assigned to the second transmitting device group including at least one transmitting device 11c. Assign (corresponding to step S25 in FIG. 9).
Further, one or a plurality of subchannels that are not used by the transmission device 11c of the second transmission device group are used for each of the transmission devices of the first transmission device group including the plurality of transmission devices 11a and 11b, and a part thereof Are assigned so as to overlap (corresponding to step S24 in FIG. 9).
Then, each of the plurality of transmission devices 11a and 11b configuring the first transmission device group transmits to the reception device 10 a frequency signal in which some frequency bands of the subchannel overlap.
Then, the transmission device 11c constituting the second transmission device group uses the frequency band of the subchannel not used by each of the transmission devices 11a and 11b constituting the first transmission device group as the reception device 10. Send a frequency signal.

In the third embodiment of the present invention, the third transmission device 11c transmits a signal to the reception device 10 using a predetermined subchannel. In addition, the first transmission device 11a and the second transmission device 11b transmit signals to the reception device 10 by overlapping a part of subchannels other than the predetermined subchannel used by the third transmission device 11c.
In the present embodiment, when the entire assignable transmission band is divided into a plurality of subchannels, the signal of the third transmission device 11c can be arranged in the subchannel determined at the system level. That is, in this embodiment, communication with a larger amount of information can be performed without affecting the system.

In the first to third embodiments described above, a further signal is multiplexed in a frequency band that is vacated by spectrum overlap resource management (SORM) or vacated by a predetermined bandwidth. As a result, more information can be transmitted from the transmission devices 11a to 11c to the reception device 10 without changing the transmission rate by spectrum overlap resource management (SORM) and without expanding the bandwidth. Further, high frequency utilization efficiency, that is, throughput can be achieved.

The first or second embodiment described above is used when there are a plurality of transmission apparatuses that ensure orthogonal discrete frequencies that do not use the same discrete frequency as other transmission apparatuses, such as the third transmission apparatus 11c. It may be applied.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described. In the first to third embodiments, the method of allocating the remaining subcarriers to other users after a plurality of users select subcarriers by SORM has been described. The order of allocation may be changed, that is, after other users select subcarriers, the remaining subcarriers may be selected by a plurality of users using SORM.

In the present embodiment, a method of using subcarriers allocated from the base station apparatus, instead of a method in which each user selects a subcarrier according to a propagation path as in the case of SORM, will be described.
In the present embodiment, the number of subcarriers in the entire band is 16, and the number of subcarriers used by the user U1 who uses the first transmission device is 8. Further, the number of subcarriers used by the user U2 using the second transmission device is 8, and the number of subcarriers used by the user U3 using the third transmission device is 3. And user U1 and user U2 use three subcarriers redundantly. Moreover, in this embodiment, the base station apparatus which becomes a receiving apparatus designates the subcarrier which each user uses.

FIG. 10 is a table showing an example of logical subcarrier numbers designated by the base station apparatus according to the fourth embodiment of the present invention. In this embodiment, first, the base station apparatus specifies a logical subcarrier number used by each user.
Here, logical subcarrier numbers 1, 2, 3, 4, 5, 6, 7, and 8 are assigned to user U1.
Also, logical subcarrier numbers 6, 7, 8, 9, 10, 11, 12, and 13 are assigned to the user U2.
Further, logical subcarrier numbers 14, 15, and 16 are assigned to the user U3.
However, three logical subcarrier numbers 6, 7, and 8 are redundantly used by the user U1 and the user U2.

FIG. 11 is a diagram illustrating an example of mapping between logical subcarrier numbers and physical subcarrier numbers according to the fourth embodiment of the present invention. In FIG. 11, the horizontal axis is frequency (subcarrier number), and the vertical axis is time.
The numbers in the 16 squares in the top row in FIG. 11 indicate physical subcarrier numbers. Further, the numbers in the squares of 4 rows × 16 columns of time T1, T2, T3, and T4 indicate the logical subcarrier numbers assigned to the physical subcarrier numbers.

Logical subcarrier numbers indicated by 1, 2, 3, 4, and 5 at times T1 to T4 are subcarriers used by the user U1. Further, logical subcarrier numbers indicated by 9, 10, 11, 12, and 13 at times T1 to T4 are subcarriers used by the user U2.
The logical subcarrier numbers indicated by 6, 7, and 8 at times T1 to T4 are subcarriers used by the user U3. Further, logical subcarrier numbers indicated by 14, 15, and 16 at times T1 to T4 are subcarriers used by the user U4.

In FIG. 11, the mapping changes with time (T1 to T4), but this change is an example, and the mapping does not have to change with time. This mapping is notified to each user from the base station apparatus before communication.
Each user determines a logical subcarrier number assigned in advance and a subcarrier to be used using mapping.

FIG. 12 is a table showing an example of physical subcarrier numbers used by each user at time T3 in the fourth embodiment of the present invention.
User U1 uses the subcarrier numbers 1, 2, 5, 6, 9, 10, 13, and 14 at time T3.
Further, the user U2 uses the subcarrier numbers of 3, 4, 6, 7, 10, 11, 14, 15 at time T3.
Also, the user U3 uses the 8, 12, and 16 subcarrier numbers at time T3.

In the present embodiment, a terminal that uses a subcarrier redundantly and a terminal that selects a subcarrier independently coexist regardless of propagation path conditions. The same method can be used even when subcarriers are grouped.
In this way, by using the subcarriers in duplicate, it is possible to multiplex other users and improve the throughput. As the transmission device and the reception device used in the present embodiment, the same configuration as that of the transmission device (FIG. 2) and the reception device (FIG. 3) according to the first embodiment can be used.

In this embodiment, the base station apparatus determines and notifies physical subcarrier allocation. In addition, when using physical subcarriers determined using pseudo-random numbers that can be generated deterministically and information (user ID, etc.) required for communication used when establishing a communication line, physical subcarrier allocation No designation or notification is required. Even in this case, this embodiment is essentially the same.

In the embodiment described above, a computer-readable program for realizing the functions of the respective units of the first to third transmitting apparatuses 11a to 11c (FIG. 2) and the respective units of the receiving apparatus 10 (FIG. 3) is possible. You may record on a recording medium. Then, the programs recorded on the recording medium are read into a computer system (not shown) incorporated in the transmission devices 11a to 11c and the reception device 10 and executed, thereby executing the first to third transmission devices 11a to 11c. Alternatively, the receiving device 10 may be controlled. The “computer system” here includes an OS and hardware such as peripheral devices.

Further, the “computer-readable recording medium” means a storage device such as a flexible disk, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” is a medium that dynamically holds a program for a short time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, In this case, it includes a program that holds a program for a certain time, such as a volatile memory inside a computer system that serves as a server or a client. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and the design and the like within the scope of the present invention are also within the scope of the claims. include.

The present invention can be applied to a wireless communication system, a communication device, a program, a wireless communication method, and the like that can transmit a signal from a transmission device to a reception device with high frequency utilization efficiency.

DESCRIPTION OF SYMBOLS 10 ... Reception apparatus, 11a ... 1st transmission apparatus, 11b ... 2nd transmission apparatus, 11c ... 3rd transmission apparatus, 31 ... Propagation path estimation part, 32 ... Signal detection unit, 1001... Encoding unit, 1002... Interleaving unit, 1003... Modulation unit, 1004... S / P conversion unit, 1005. DESCRIPTION OF SYMBOLS 1007 ... IDFT part, 1008 ... P / S conversion part, 1009 ... Pilot signal generation part, 1010 ... Pilot multiplexing part, 1011 ... CP insertion part, 1012 ... D / A conversion , 1013... Radio unit, 1014... Transmit antenna, 2001... Receive antenna, 2002... Radio unit, 2003... A / D converter, 2004. ..Pyro Separation unit, 2006-1, 2006-2 ... propagation path estimation unit, 2007 ... scheduling unit, 2008 ... spectrum allocation information generation unit, 2009 ... buffer, 2010 ... first S / P conversion unit, 2011 ... first DFT unit, 2012 ... spectrum demapping unit, 2013-1, 2014-2 ... soft cancellation unit, 2014-1, 2014-2 ... equalization , 2015-1, 2015-2 ... demodulator, 2016-1, 2016-2 ... deinterleaver, 2017-1, 2017-2 ... decoder, 2018-1, 2018-2 ..Interleave units, 2019-1, 2019-2... Soft replica generation units, 2020-1, 2020-2... Second S / P conversion units, 2021-1, 2021-2 ... the second DFT unit, 2022-1,2022-2 ... interference extraction unit

Claims (10)

1. A communication system comprising a receiving device and first to third transmitting devices,
   The first transmission device and the second transmission device transmit signals to the reception device by overlapping some frequency bands,
   The third transmission device is a communication system that transmits a signal to the reception device using a frequency band that is not used by the first and second transmission devices.
2. A communication system comprising a receiving device and first to third transmitting devices,
   The third transmitting device transmits a signal to the receiving device using a predetermined frequency band,
   The first transmission device and the second transmission device are communication systems that transmit a signal to the reception device by overlapping a part of a frequency band other than the predetermined frequency band.
3. The communication system according to claim 2, wherein the frequency band used by the third transmission device is determined based on a frequency having a small sum of reception signal noise ratios of the first and second transmission devices.
4. A communication system comprising a receiving device and first to third transmitting devices,
   The third transmitting device transmits a signal to the receiving device using a predetermined subchannel,
   The communication system in which the first transmission device and the second transmission device transmit signals to the reception device by overlapping a part of subchannels other than the predetermined subchannel.
5. 5. The total transmission bandwidth of subchannels used by the first transmission device and the second transmission device is larger than a transmission bandwidth to which signals of the first transmission device and the second transmission device can be allocated. The communication system according to 1.
6. A communication device that communicates with the first to third transmission devices,
   A first allocation unit that allocates a frequency band obtained by overlapping a part of frequency bands to the first transmission device and the second transmission device;
   A second allocation unit that allocates a frequency band that is not allocated to the first and second transmission devices to the third transmission device;
   A communication device comprising:
7. A communication device computer for communicating with the first to third transmission devices;
   First allocating means for allocating a frequency band obtained by overlapping a part of frequency bands to the first transmitting apparatus and the second transmitting apparatus;
   A program for causing a frequency band that is not allocated to the first and second transmission apparatuses to function as a second allocation unit that allocates a frequency band to the third transmission apparatus.
8. A communication method using a first transmission device group including a plurality of transmission devices, a second transmission device group including at least one transmission device, and a reception device,
   Assigning the frequency bands to each of the transmission devices of the first transmission device group so as not to overlap;
   Changing a part of the frequency band to overlap;
   A process of assigning non-overlapping frequency bands including a frequency band vacated by changing the overlapping to the transmitting apparatuses of the second transmitting apparatus group,
   Each of a plurality of transmission devices constituting the first transmission device group transmits a frequency signal with the partial frequency band overlapping to the reception device;
   The transmitting device constituting the second transmitting device group transmits a frequency signal to the receiving device using a frequency band not used by each of the transmitting devices constituting the first transmitting device group; ,
   A communication method.
9. A communication method using a first transmission device group including a plurality of transmission devices, a second transmission device group including at least one transmission device, and a reception device,
   Assigning a frequency band to the transmission devices of the second transmission device group;
   A process of assigning to each of the transmission devices of the first transmission device group a frequency band that is not used by the transmission devices of the second transmission device group so that a part thereof overlaps;
   Each of a plurality of transmission devices constituting the first transmission device group transmits a frequency signal with the partial frequency band overlapping to the reception device;
   The transmitting device constituting the second transmitting device group transmits a frequency signal to the receiving device using a frequency band not used by each of the transmitting devices constituting the first transmitting device group; ,
   A communication method.
10. A communication method using a first transmission device group composed of a plurality of transmission devices, a second transmission device group composed of at least one transmission device, and a reception device,
    Dividing the frequency band into sub-channels for each frequency band of a predetermined width;
    Assigning one or more subchannels to the transmitters of the second transmitter group;
    A process of using one or a plurality of subchannels that are not used by the transmission devices of the second transmission device group and assigning the frequency bands to overlap each of the transmission devices of the first transmission device group. When,
    Each of the plurality of transmission devices constituting the first transmission device group transmits a frequency signal in which some of the frequency bands of the subchannel overlap to the reception device;
    The transmission devices that constitute the second transmission device group transmit frequency signals to the reception devices using frequency bands of subchannels that are not used by the transmission devices that constitute the first transmission device group. The process of
    A communication method.

Images