JP6035533B2 - Base station apparatus and processor - Google Patents

Description

  The present invention relates to a base station apparatus and a processor.

  2. Description of the Related Art In recent years, in a mobile communication system, capacity has been increased by cell splitting such as wideband and small cells in order to improve a peak data rate, while traffic has increased dramatically. However, since the frequency resources are limited, there is a limit to the extension of usable frequencies. Therefore, improvement of frequency utilization efficiency is an issue.

  In communication in a mobile communication system, a base station apparatus configures a cell and performs communication with a plurality of mobile station apparatuses existing in the cell. When a base station apparatus receives signals from a plurality of mobile station apparatuses at the same time, generally, the base station apparatus maintains the orthogonality among the signals from the plurality of mobile station apparatuses, thereby causing interference between the mobile station apparatuses (also referred to as inter-user interference). An access scheme that reduces the Examples of such access schemes that maintain orthogonality (hereinafter referred to as orthogonal access schemes) include frequency division multiple access (FDMA), time division multiple access (TDMA), and code division. There exist multiple access (CDMA: Code Division Multiple Access), spatial division multiple access (SDMA: Space Division Multiple Access, multiple-input multiple-output (MIMO), etc.).

  In LTE (Advanced Term Evolution) and LTE-Advanced, which is one of the standardization organizations, the specifications are being studied in 3GPP (The Third Generation Partnership Project) and LTE-Advanced. Orthogonal frequency division multiplexing (OFDM) is used in the downlink (communication from the base station apparatus to the mobile station apparatus). Further, in uplink (communication from a mobile station apparatus to a base station apparatus), DFT-S-OFDM (Discrete Fourier Transform Spread Frequency Spread OFDM) or cluster discrete Fourier transform spread orthogonal frequency division multiplexing. (Clustered DFT-S-OFDM), N × DFT-S-OFDM is used.

  These adopted access methods are approaches for realizing large-capacity transmission based on FDMA. However, when a plurality of mobile station apparatuses communicate simultaneously, maintaining the orthogonality between signals used by the mobile station apparatus for communication limits the room for improving frequency utilization efficiency. The reason is that when a base station apparatus allocates different frequency bands for data transmission to a plurality of mobile station apparatuses that perform data transmission at the same timing, the frequency band with a high propagation path gain is the same in the plurality of mobile station apparatuses. This is because one of the mobile station apparatuses cannot use a frequency band with a high propagation path gain. Therefore, a non-orthogonal access scheme that eliminates the limitation of orthogonality has been proposed. The non-orthogonal access method is attracting attention as a communication method that can improve the frequency utilization efficiency compared to the orthogonal access method (see Non-Patent Document 1).

  In the non-orthogonal access scheme in the uplink, on the premise of turbo equalization and successive interference cancellation (SIC) processing that are interference cancellers in reception processing, the number of multiplexes that can be separated by a plurality of mobile station devices exceeds the multiplex number There is a method of assigning signals to the same time and the same frequency (see Patent Document 1). Comparing the technique described in Patent Document 1 with FDMA, the technique described in Patent Document 1 uses a non-orthogonal access method to expand the frequency band that can be used by each mobile station apparatus, and to improve the frequency utilization efficiency. Can be improved. When at least a part of a frequency band used for data transmission by a mobile station apparatus overlaps with a frequency band used for data transmission by another mobile station apparatus, the frequency utilization efficiency that can be achieved improves as the duplication rate increases. Here, the overlap rate is a ratio of a bandwidth that overlaps a frequency band used by another mobile station device in a bandwidth used by the mobile station device to a bandwidth used by the mobile station device. .

International Publication No. 2009/022709

P. Wang, J.M. Xiao, L. Ping, “Comparison of orthologonal and non-orthogonal approaches to future, wireless cellular systems,” IEEE Vehicular Technology, V .. 1, no. 3, pp. 4-11, Sept. 2006.

  However, the technique described in Patent Document 1 increases the inter-user interference as the duplication rate increases. For this reason, when the transmission characteristic is set to a high overlapping rate that causes interference between users that cannot be removed by interference cancellation, degradation occurs, and as a result, frequency utilization efficiency also decreases. Further, if the overlapping rate is too low, there is a problem that the frequency utilization efficiency is deteriorated.

  The present invention has been made in view of such circumstances, and provides a base station apparatus and a processor capable of determining communication parameters so as to obtain good frequency utilization efficiency.

  (1) The present invention has been made to solve the above problems, and one aspect of the present invention allocates frequency resources used for data transmission to a plurality of mobile station apparatuses, and assigns information on the frequency resources. A base station apparatus that notifies the plurality of mobile station apparatuses and simultaneously receives signals transmitted from the plurality of mobile station apparatuses, and the frequency resources of the frequency resources that the plurality of mobile station apparatuses can use in an overlapping manner A duplication rate determining unit that determines a permissible duplication rate that is an index of the number according to communication parameters, and allocation of the frequency resources used by the plurality of mobile station apparatuses for the data transmission so as to satisfy the permissible duplication rate And a scheduling unit.

  According to the present invention, communication parameters can be determined so that good frequency utilization efficiency can be obtained.

It is a conceptual diagram which shows an example of the uplink of the radio | wireless communications system which concerns on the 1st Embodiment of this invention. It is a schematic block diagram which shows an example of a structure of the mobile station apparatus which concerns on this embodiment. It is a conceptual diagram which shows an example which the mobile station apparatus which concerns on this embodiment is a non-continuous frequency allocation, and uses a non-orthogonal access system. It is a schematic block diagram which shows an example of a structure of the base station apparatus which concerns on this embodiment. It is a schematic block diagram which shows an example of a structure of the reception process part of the base station apparatus which concerns on this embodiment. It is a figure which shows an example of the table for the duplication rate determination part which concerns on this embodiment to determine an allowable duplication rate based on the communication parameter of the number of antennas. It is a figure which shows an example of the error rate characteristic by computer simulation in case the base station apparatus which concerns on this embodiment uses one antenna for reception. It is a figure which shows an example of the error rate characteristic by computer simulation in case the base station apparatus which concerns on this embodiment uses two antennas for reception. It is a schematic block diagram which shows an example of a structure of the base station apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows an example of the table for the duplication rate determination part which concerns on this embodiment to determine an allowable duplication rate based on the information which shows the number of users who allocate a frequency resource at the next transmission opportunity. It is a figure which shows an example of the error rate characteristic by computer simulation in case the number of antennas which the base station apparatus which concerns on this embodiment uses is two, and the number of mobile station apparatuses is two. It is a figure which shows an example of the error rate characteristic by computer simulation in case the number of antennas which the base station apparatus which concerns on the 2nd Embodiment of this invention uses for reception is 2, and the number of mobile station apparatuses is 4. It is a schematic block diagram which shows an example of a structure of the base station apparatus which concerns on the 3rd Embodiment of this invention. It is the schematic which shows an example of the table for the duplication rate determination part which concerns on this embodiment to determine an allowable duplication rate based on the information which shows the duplication rate of the number of clusters.

  Embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, an example of a data transmission method will be described as a single carrier method (DFT-S-OFDM, Clustered DFT-S-OFDM), but the present invention is not limited to this. For example, the following embodiments can be applied to a data transmission method using any transmission method such as OFDM or N × DFT-S-OFDM which is a multicarrier method. Further, in each of the following embodiments, the transmission device is a mobile station device, the reception device is a base station device, and the mobile station device has one antenna. However, the mobile station device has a plurality of antennas. As described above, the present invention can be applied even when a transmission / reception diversity technique or a MIMO transmission technique is used. Here, the number of antennas included in the transmission apparatus is not limited to the number of physical antennas, and may be the number of antenna ports or the number of antenna layers. The number of antenna ports is set to 1 if the receiving apparatus does not need to recognize that there are a plurality of antennas.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a conceptual diagram showing an example of an uplink of the radio communication system S1 according to the first embodiment of the present invention.
The wireless communication system S1 of FIG. 1 includes a base station device 2 and two mobile station devices 1-1 and 1-2 that are communicatively connected to the base station device 2. The base station apparatus 2 includes a cell CE1 that is a communication range. The mobile station apparatuses 1-1 and 1-2 exist in the cell CE 1 and communicate with the base station apparatus 2. The base station apparatus 2 determines communication parameters used for uplink data transmission based on the communication quality between the own apparatus and the mobile station apparatuses 1-1 and 1-2.

  The base station apparatus 2 notifies the determined communication parameters to the mobile station apparatuses 1-1 and 1-2 as control information. The communication parameters include frequency resource allocation, modulation and coding scheme (MCS) used for uplink data transmission, type of access method, transmission power control value (TPC: Transmit Power Control), and retransmission control. Signals etc. are included.

  Here, the frequency resource allocation is either a frequency resource allocation using a continuous frequency band or a frequency resource allocation using a discontinuous frequency band, and further maintains orthogonality with other mobile station apparatuses in the frequency domain. Non-orthogonal access schemes can also be assigned. In frequency resource allocation using a continuous frequency band, the start position of the allocated frequency band and the bandwidth of the frequency band are specified using 12 subcarriers, which are the minimum unit of allocation, as a resource block (RB).

  Frequency resource allocation using a non-contiguous frequency band allocates non-contiguous frequency resources using a resource block group (RBG: RB Group) in which one subcarrier, one RB, or a plurality of RBs are grouped as a minimum unit of allocation. Here, if a continuous frequency band among the allocated frequency resources is referred to as one cluster, the non-continuous frequency resource to be allocated may have either an upper limit of the number of clusters or no upper limit. Specifically, in the case of allocation in units of RBGs, the upper limit number of clusters composed of consecutive RBGs may be determined as 2 sets, or the upper limit number of clusters may be determined as 3 sets or more. .

  The mobile station apparatuses 1-1 and 1-2 perform uplink data transmission based on communication parameters included in the received control information. Here, the mobile station apparatuses 1-1 and 1-2 use a method specified by the base station apparatus 2 among frequency resource allocation using a continuous frequency band or frequency resource allocation using a discontinuous frequency band. Perform data transmission. Note that the data transmission of the mobile station apparatuses 1-1 and 1-2 may or may not be notified of whether FDMA or non-orthogonal access in which orthogonality in the frequency domain is maintained.

FIG. 2 is a schematic block diagram illustrating an example of the configuration of the mobile station apparatuses 1-1 to 1-m according to the present embodiment.
Here, m is the number of mobile station apparatuses connected to the base station apparatus 2 described later, and each mobile station apparatus 1-l (l = 1, 2,..., M) performs data transmission processing. Since all mobile station apparatuses have the same configuration, only the mobile station apparatus 1-1 will be described, and description of other mobile station apparatuses will be omitted. The mobile station apparatus 1-1 includes a control information receiving unit 101, a coding unit 102, a modulation unit 103, a DFT unit 104, a frequency mapping unit 105, an IFFT unit 106, a reference signal multiplexing unit 107, and a transmission process. Unit 108 and a transmission antenna 109. Although the mobile station apparatus 1-1 has other generally known mobile station apparatus functions, illustration and description thereof are omitted.

  The control information receiving unit 101 receives control information from the base station apparatus 2. This control information includes frequency resource allocation information used by the mobile station apparatus 1-1 for data transmission, information on MCS, communication parameters, and the like. Control information reception section 101 outputs information indicating the coding rate included in MCS to encoding section 102 and information indicating the modulation scheme included in MCS to modulation section 103, respectively. Control information receiving section 101 outputs frequency resource allocation information to frequency mapping section 105.

  The encoding unit 102 encodes an input data bit with an error correction code. For example, a turbo code, a low density parity check (LDPC) code, a convolutional code, a Hamming code, or the like is used as the error correction code. The type of error correction code applied by the encoding unit 102 may be determined in advance for each transmission / reception device or each transmission / reception opportunity, or may be notified as control information. In addition, the type of error correction coding may be determined based on the information related to the overlap rate by receiving information related to the overlap rate of the frequency band. Based on the information indicating the coding rate input from the control information receiving unit 101, the coding unit 102 performs an operation called puncturing, in which parity bits are regularly omitted from the coded data bits. Encoding section 102 outputs data bits (hereinafter referred to as encoded bits) subjected to post-puncture encoding to modulation section 103.

  Modulation section 103 modulates the encoded bits input from encoding section 102 with a modulation scheme of information indicating the modulation scheme input from control information receiving section 101, thereby generating a modulation symbol. Examples of the modulation scheme include quadrature phase shift keying (QPSK), 16-value quadrature amplitude modulation (16QAM: 16-ary quadrature amplitude modulation), and 64-value quadrature amplitude modulation (64QAM). Modulation section 103 outputs the generated modulation symbol to DFT section 104.

The DFT unit 104 performs discrete Fourier transform on the modulation symbol sequence input from the modulation unit 103 to convert the time domain signal into the frequency domain signal, and outputs the converted frequency domain signal to the frequency mapping unit 105.
The frequency mapping unit 105 arranges the signal input from the DFT unit 104 in the allocated frequency band based on the frequency resource allocation information input from the control information receiving unit 101. For example, in the case of non-orthogonal access transmission, the frequency mapping unit 105 of the mobile station apparatus 1-1 uses the frequency band assigned to the other mobile station apparatus 1-1 (l = 2,..., M). At least a part of the signal is assigned to the same frequency band. Here, FIG. 3 shows an example in which the mobile station apparatuses 1-1 and 1-2 have non-contiguous frequency allocation and further use a non-orthogonal access scheme.

FIG. 3 is a conceptual diagram illustrating an example in which the mobile station apparatuses 1-1 and 1-2 according to the present embodiment are non-contiguous frequency allocation and use a non-orthogonal access scheme.
The frequency assignment F1-1 is a frequency assigned to the mobile station apparatus 1-1, and the frequency assignment F1-2 is an example of a frequency assigned to the mobile station apparatus 1-2.
Since it is a non-orthogonal access method, the transmission signals of the mobile station apparatuses 1-1 and 1-2 are overlapped in the frequency domain without depending on the number of reception antennas of the base station apparatus 2. Frequency mapping section 105 outputs a signal (hereinafter referred to as an allocated frequency signal) arranged at the assigned frequency to IFFT section 106.

  The IFFT unit 106 performs inverse fast Fourier transform (IFFT) on the assigned frequency signal input from the frequency mapping unit 105, thereby converting the frequency domain signal into a time domain signal (hereinafter referred to as a time domain data signal). Convert to IFFT section 106 outputs the obtained time domain data signal to reference signal multiplexing section 107.

  The reference signal multiplexing unit 107 performs a process of forming a transmission frame by multiplexing a reference signal known by the transceiver in the time domain data signal input from the IFFT unit 106 in the time domain. However, the present invention is not limited to this, and the mobile station apparatus 1-1 may perform the process of configuring the transmission frame by multiplexing the reference signal in the frequency domain. The reference signal multiplexing unit 107 outputs the multiplexed reference signal to the transmission processing unit 108.

  The transmission processing unit 108 inserts a CP (Cyclic Prefix) into the signal obtained by multiplexing the reference signal input from the reference signal multiplexing unit 107. The transmission processing unit 108 converts the signal into which the CP is inserted into an analog signal by D / A (Digital to Analog) conversion, and up-converts the converted signal to a radio frequency. The transmission processing unit 108 amplifies the upconverted signal with a PA (Power Amplifier) and transmits the amplified signal via the transmission antenna 109. The mobile station apparatuses 1-2 to 1-m also perform data transmission by the same processing as the mobile station apparatus 1-1.

FIG. 4 is a schematic block diagram illustrating an example of the configuration of the base station apparatus 2 according to the present embodiment.
The base station apparatus 2 has Nr receiving antennas, and Nr is an integer of 1 or more.
The base station apparatus 2 includes reception antennas 201-1 to 201-Nr, reception processing units 202-1 to 202-Nr, an antenna information management unit 203, an overlap rate determination unit 204, a scheduling unit 205, and control information. Generation unit 206, control information storage unit 207, control information transmission unit 208, soft canceller unit 209, equalization unit 210, IDFT units 211-1 to 211-n, and synthesis units 212-1 to 212- n, demodulation units 213-1 to 213-n, decoding units 214-1 to 214-n, soft symbol generation units 215-1 to 215-n, DFT units 216-1 to 216-n, reception It includes signal soft replica generation units 217-1 to 217-n. Although the base station apparatus 2 has other generally known base station apparatus functions, illustration and description thereof are omitted.

  Receiving antennas 201-1 to 201-Nr simultaneously receive signals transmitted from mobile station apparatuses 1-1 to 1-m and output the signals to reception processing units 202-1 to 202-Nr. Since the reception processing units 202-1 to 202-Nr perform similar processing, only the kth reception processing unit 202-k (k = 1, 2,..., N) will be described here. An example of the configuration of the reception processing unit 202-k is the block diagram shown in FIG.

FIG. 5 is a schematic block diagram illustrating an example of the configuration of the reception processing unit 202-k of the base station device 2 according to the present embodiment.
The reception processing unit 202-k includes a reception signal processing unit 2021-k, a reference signal separation unit 2022-k, an FFT unit 2023-k, and a frequency demapping unit 2024-k.
The received signal processing unit 2021-k receives a signal received by the receiving antenna 201-k. Received signal processing section 2021-k downconverts to a baseband frequency, and converts the downconverted signal into a digital signal by performing A / D (Analog to Digital) conversion. Further, reception signal processing section 2021-k removes the CP from the digital signal, and inputs the signal from which the CP has been removed to reference signal separation section 2022-k.

  The reference signal separation unit 2022-k separates the reference signal and the data signal from the signal from which the CP input from the reception signal processing unit 2021-k is removed. Here, the reference signal refers to a sounding reference signal (SRS) transmitted to obtain a propagation path estimation value used for scheduling and a demodulation reference signal transmitted to obtain a propagation path estimation value used at the time of demodulation. (DMRS: Demodulation Reference Signal). The reference signal separation unit 2022-k outputs the separated reference signal to the scheduling unit 205, and outputs the data signal, which is the remaining signal obtained by separating the reference signal, to the FFT unit 2023-k.

  The FFT unit 2023-k converts the data signal input from the reference signal separation unit 2022-k from a time domain signal to a frequency domain signal by a fast Fourier transform, and the frequency domain signal is converted into a frequency demapping unit 2024. Output to -k. The frequency demapping unit 2024-k reads out information on the mobile station apparatus that has transmitted the signal from the control information storage unit 207 and frequency resource allocation information on each mobile station apparatus. The frequency demapping unit 2024-k extracts the frequency domain signal of each user based on the read frequency resource allocation information, and inputs the extracted frequency domain signals of all mobile station devices to the soft canceller unit 209.

  In FIG. 4, the scheduling unit 205 receives the reference signal received from the reception processing units 202-1 to 202 -Nr and the allowable overlap rate used for scheduling from the overlap rate determination unit 204. Here, the allowable duplication rate is an upper limit value of the duplication rate determined based on the communication parameter input from the antenna information management unit 203 in the duplication rate determination unit 204, and is a frequency resource used by each of the plurality of mobile station apparatuses. The ratio of the total number of frequency resources to the number of frequency resources that can be allocated.

The allowable duplication rate is determined by adding at least one of the plurality of mobile station apparatuses among the total number of frequency resources of the frequency resources used by each of the plurality of mobile station apparatuses and the number of frequency resources of the assignable frequency resources. It may be a ratio of the allocated frequency resources to the number of frequency resources.
The duplication rate determination unit 204 decides an allowable duplication rate, which is an index of the number of frequency resources that can be used by a plurality of mobile station apparatuses in an overlapping manner, based on communication parameters. Here, the communication parameter is the number of antenna ports used for reception by the base station device,
The duplication rate determination unit 204 increases the allowable duplication rate as the number of antenna ports increases.

  The antenna information management unit 203 manages the number of energized antennas or the number of antennas used for data reception from the terminal device 1-1. The antenna information management unit 203 outputs the number of antennas used by the base station device 2 for data reception or the number of energized antennas to the duplication rate determination unit 204. Based on the number of antennas input from the antenna information management unit 203, the duplication rate determination unit 204 determines the allowable duplication rate as in a table T1 illustrated in FIG.

FIG. 6 is a diagram illustrating an example of a table T1 managed by the antenna information management unit 203 for determining the allowable duplication rate based on the number of antennas as communication parameters by the duplication rate determination unit 204 according to the present embodiment.
As shown in the figure, the table T1 includes columns for each item of the number of receiving antennas (Nr) to be used and the allowable overlapping rate. The table T1 is two-dimensional tabular data having rows and columns in which information on the allowable duplication rate is stored for each number of receiving antennas (Nr) to be used.
The number of receiving antennas (Nr) used in the first row is NR1, and the allowable overlap rate corresponding to it is NOV1. Further, the number of receiving antennas (Nr) used in the second row is NR2, and the allowable overlapping rate corresponding to it is NOV2. Furthermore, the number of receiving antennas (Nr) used in the third row is NR3, and the allowable overlapping rate corresponding to it is NOV3.

  However, NR1 <NR2 <NR3, NOV1 ≦ NOV2 ≦ NOV3, and NOV1 <NOV3. For example, NR1 = 1, NR2 = 2, NR3 = 4, NOV1 = 20%, NOV2 = 30%, NOV3 = 40%. Depending on the number of reception antennas used by the base station apparatus 2, the error rate characteristic and throughput characteristic of the performance in the reception process vary greatly, so that an appropriate allowable overlap rate can be controlled.

  Scheduling section 205 estimates channel characteristics (frequency response) between mobile station apparatuses 1-1 to 1-m based on the reference signal input from reception processing section 202-k. Further, the scheduling unit 205 schedules the frequency resource allocation used by each mobile station apparatus 1-1 to 1-m at the next transmission opportunity based on the estimated propagation path characteristics and the allowable overlapping rate determined by the overlapping rate determining unit 204. decide. Here, for scheduling, for example, a non-orthogonal access method within a range that does not deviate from the allowable duplication rate is used.

  Therefore, in scheduling, when the allowable duplication rate is not exceeded, frequency resource allocation is determined only from the propagation path characteristics, and when the allowable duplication rate is reached, frequency resource allocation is determined by scheduling based on FDMA. That is, when the number of receiving antennas used for reception by the base station apparatus 2 is NR2, the scheduling method uses the overlapping rates of the mobile station apparatuses 1-1 to 1-m as O1, O2,..., Oi,. If Om, it is necessary to satisfy Oi ≦ NOV2 for any i satisfying 1 ≦ i ≦ m.

  Specifically, the scheduling unit 205 performs scheduling for each mobile station apparatus 1-1 to 1-m in consideration of only the channel gain within a range not exceeding the overlap rate, and the mobile station device exceeding the overlap rate Is present, scheduling is performed except for the frequency band used by the mobile station apparatus. Furthermore, when all mobile station apparatuses exceed the duplication rate, the scheduling unit 205 performs scheduling so that there is no duplication in PF (Proportional Fairness) scheduling.

As another scheduling method, frequency resource allocation may be determined within a range that does not exceed the allowable duplication rate within the system band, instead of limiting the allowable duplication rate for each mobile station apparatus. Specifically, the scheduling unit 205 performs scheduling considering only the channel gain within a range that does not exceed the allowable duplication rate within the system band, and performs PF scheduling when the allowable duplication rate is exceeded within the system band. . In this case, since the duplication rate in each of the mobile station devices 1-1 to 1-m may exceed the allowable duplication rate, scheduling is more flexible. Specifically, when the number of reception antennas used for reception by the base station apparatus 2 is NR2, the overlap rate O _sys within the system band is determined by the system-assignable bandwidth B _sys and the mobile station apparatuses 1-1 to 1- It is calculated by the formula (1) from the use bandwidths B ₁ to B _{m of m} , and O _sys ≦ NOV 2 needs to be satisfied.

However, if the overlap rate O _sys in the system band is 0 or more and the total of the used bandwidths B ₁ to B _m is the same or smaller than the bandwidth B _sys that can be allocated by the system, the overlap in the system band The rate is 0. In this case, the bandwidth usage rate B _u is calculated from the equation (2).

Further, the overlap rate O _sys in the system band can be calculated from the equation (3) using the bandwidth B _{used used} for communication within the _allocatable bandwidth instead of the _allocatable bandwidth B _sys. Good.

However, when the overlap rate O _sys in the system band is 0 or more, and the total of the used bandwidths B ₁ to B _m is equal to or smaller than the bandwidth B _used used for communication within the _allocatable bandwidth The overlap rate in the system band is 0.

  The scheduling unit 205 outputs the determined frequency resource allocation information to the control information generation unit 206. Scheduling section 205 also determines MCS and the like based on frequency resource allocation information and propagation path characteristics, and outputs them to control information generation section 206. Furthermore, when a reference signal used for demodulation is input from reception processing section 202-k, scheduling section 205 outputs the estimated propagation path characteristic to equalization section 210.

The control information generation unit 206 converts information such as frequency allocation information and MCS input from the scheduling unit 205 into a predetermined control information format, and generates control information. The control information generation unit 206 stores the generated control information in the control information storage unit 207. The control information generation unit 206 outputs the generated control information to the control information transmission unit 208.
The control information storage unit 207 stores the control information generated by the control information generation unit 206.
The control information transmission unit 208 transmits the control information input from the control information generation unit 206 to each mobile station device.

  On the other hand, soft canceller section 209 receives the signals of all mobile station apparatuses extracted in reception processing sections 202-1 to 202-Nr. The soft canceller unit 209 receives the received signal soft replica and the inter-user interference (IUI) soft replica from the received signal soft replica generation units 217-1 to 217-n, and receives the signal of each user. Perform interference cancellation. Soft canceller section 209 outputs the signals of all mobile station apparatuses after interference cancellation to equalization section 210.

The equalization unit 210 generates equalization weights based on a minimum mean square error (MMSE) standard from the channel characteristics input from the soft canceller unit 209, and multiplies the signal after soft cancellation. The equalization unit 210 outputs the signal of each mobile station device after equalization to each of the IDFT units 211-1 to 211-n.
Since the processing on the received signal of each mobile station apparatus in the IDFT sections 211-1 to 211-n and the decoding sections 214-1 to 214-n is the same process, the received signal of the mobile station apparatus 1-1 is used. The processing for will be described.

The l-th IDFT unit 211-k converts the equalized reception signal input from the equalization unit 210 into a time domain signal. The IDFT unit 211-k outputs the converted time domain signal to the synthesis unit 212-k.
The combining unit 212-k combines the soft symbol input from the soft symbol generation unit 215-k and the time domain signal input from the IDFT unit 211-k by adding replicas. The synthesis unit 212-k outputs the synthesized signal to the demodulation unit 213-k.
The demodulating unit 213-k reads information indicating the modulation scheme included in the MCS used for data transmission by the mobile station apparatus 1-1 from the control information storage unit 207, and uses the read modulation scheme from the combining unit 212-k. The inputted combined signal is demodulated to obtain an LLR (Log Likelihood Ratio). The demodulator 213-k outputs the LLR to the decoder 214-k.

  The decoding unit 214-k reads information indicating the coding rate used by the mobile station apparatus 1-1 for data transmission from the control information storage unit 207, and inputs the information from the demodulation unit 213-k using the read coding rate. The decoded LLR is decoded. The data bits of the mobile station apparatuses 1-1 to 1-m after decoding are obtained by hard-decision of the decoded LLR.

When turbo equalization is performed, the decoded LLRs obtained in the decoding units 214-1 to 214-n are output to the soft symbol generation units 215-1 to 215-n.
The soft symbol generation units 215-1 to 215-n, based on the information indicating the modulation scheme used for transmission in the mobile station apparatuses 1-1 to 1-m read from the control information storage unit 207, Replica) is generated and output from the DFT units 216-1 to 216-n.

The DFT units 216-1 to 216-n convert the soft symbol replicas input from the DFT units 216-1 to 216-n from time domain signals to frequency domain signals by discrete Fourier transform. The DFT units 216-1 to 216-n output the converted frequency domain signals to the received signal soft replica generation units 217-1 to 217-n.
The reception signal soft replica generation units 217-1 to 217-n receive the propagation path characteristics estimated by the scheduling unit 205, and perform frequency domain replica signals input from the DFT units 216-1 to 216-n. A received signal soft replica is generated by multiplying the propagation path characteristic. The reception signal soft replica generation units 217-1 to 217-n output the generated reception signal soft replicas to the soft canceller unit 209.
Signal detection is performed by repeating the above processing. Here, the number of repetitions of turbo equalization may be determined in advance, or is determined by determining whether or not there is an error using cyclic redundancy check (CRC) and an upper limit value of the number of repetitions. Also good.

FIG. 7 is a diagram illustrating an example of error rate characteristics by computer simulation when the number of antennas used for reception by the base station apparatus 2 according to the present embodiment is one.
FIG. 8 is a diagram illustrating an example of error rate characteristics by computer simulation when the number of antennas used for reception by the base station apparatus 2 according to the present embodiment is two.
In the simulation specifications, the number of mobile station apparatuses is four, the modulation scheme is QPSK, the error correction code is a turbo code coding rate 1/2, and the non-orthogonal access scheme and the orthogonal access scheme based on FDMA Is shown. Further, the number of FFT points is set to 2048, the number of assignable RBs is set to 100, and non-contiguous frequency resource allocation is performed.

In these figures, the horizontal axis represents the bandwidth usage rate B _u calculated by Expression (2). Therefore, in the orthogonal access scheme based on FDMA, the bandwidth usage rate B _u = 100% is 25 when the total number of RBs allocated to each mobile station apparatus is 100 RBs, and the number of RBs used by one mobile station apparatus is 25, It means that 100 RBs that can be allocated are used by any of the four mobile station apparatuses. BER G101, G201 orthogonal access method based on FDMA because it does not permit the overlap of the frequency domain is always the band use ratio _{B u} is 100% of the characteristic.

Since the error rate characteristics G102 and G202 of the non-orthogonal access scheme allow overlap in the frequency domain, the number of RBs used by one mobile station apparatus can be increased from 25. Therefore, for example, when the bandwidth usage rate B _u of the non-orthogonal access method is 120%, the number of RBs used by one mobile station apparatus is 30.
First, in the error rate characteristic G102 of the non-orthogonal access scheme in FIG. 7, it can be realized with an error rate characteristic equivalent to the error rate characteristic G101 of the orthogonal access scheme based on FDMA until the band usage rate B _u is about 104%.
On the other hand, the error rate characteristic G202 non-orthogonal access scheme in Figure 8, until the band use ratio _{B u} of about 135% can be realized with equal error rate performance and error rate characteristic G201 orthogonal access method based on FDMA.

When the number of mobile station apparatuses is 4 and the number of RBs used by each mobile station apparatus is 25, the bandwidth usage rate B _u is 100%, and the duplication rate O _sys = 0% from Equation (1). . When the bandwidth usage rate B _u in FIG. 7 is 104%, the overlap rate O _sys = 4% from the equation (1), and when the bandwidth usage rate B _u in FIG. 8 is 135%, from the equation (1). The overlap rate O _sys = 35%.
Therefore, in this example, the communication parameters of the number of reception antennas (Nr) used in the table T1 in FIG. 6 can be set to NR1 = 1, NR2 = 2, NOV1 = 4%, and NOV2 = 35%.
Therefore, if the duplication rate that can realize an error rate characteristic equivalent to that of the orthogonal access method is an allowable duplication rate, the allowable duplication rate increases as the number of antennas increases.

  Thus, according to the present embodiment, communication parameters can be determined so that good frequency utilization efficiency can be obtained. Further, since the allowable duplication rate is determined by the number of antennas used by the base station apparatus 2 for reception, the allowable duplication rate that can maximize the system throughput in the number of antennas used by the base station apparatus 2 is different. The amount of improvement in system throughput by the method can be increased.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described in detail with reference to the drawings.
In the first embodiment, a case has been described in which the allowable duplication rate is determined by the number of antennas used by the base station device 2 at the time of reception. In the present embodiment, a case will be described in which the allowable duplication rate is determined based on the number of users who simultaneously transmit data. In the present embodiment, simultaneous data transmission means, for example, data transmission in the same slot or data transmission in the same subframe.

  The configurations of the mobile station apparatuses 1-1 to 1-m according to the present embodiment are the same as those of the mobile station apparatuses 1-1 to 1-m according to the first embodiment, and thus description thereof is omitted.

FIG. 9 is a schematic block diagram illustrating an example of the configuration of the base station device 2a according to the present embodiment.
The base station apparatus 2 includes reception antennas 201-1 to 201-Nr, reception processing units 202-1 to 202-Nr, an antenna information management unit 203, a control information generation unit 206, a control information storage unit 207, Control information transmission unit 208, soft canceller unit 209, equalization unit 210, IDFT units 211-1 to 211-n, synthesis units 212-1 to 212-n, demodulation units 213-1 to 213-n Decoding units 214-1 to 214-n, soft symbol generation units 215-1 to 215-n, DFT units 216-1 to 216-n, and received signal soft replica generation units 217-1 to 217-n. A user number control unit 303 and a duplication rate determination unit 304. Although the base station apparatus 2 has other generally known base station apparatus functions, illustration and description thereof are omitted.

  When the configuration of the base station apparatus 2a according to the present embodiment is compared with the base station apparatus 2 according to the first embodiment, the antenna information management unit 203 is deleted and a user number control unit 303 is added. Further, the method for determining the duplication rate in the duplication rate determining unit 304 is different from the method for determining the duplication rate of the duplication rate determining unit 204 in the first embodiment. Since other configurations are the same, description thereof is omitted.

  Reception processing units 202-1 to 202-Nr output reference signals separated from the received signals to scheduling unit 205 and user number control unit 303. The number-of-users control unit 303 estimates channel characteristics based on the reference signal separated from the received signal input from the scheduling unit 205, and sets the number of users to allocate frequency resources at the next transmission opportunity based on the estimated channel characteristics. decide.

  Note that the method for determining the number of users to which frequency resources are allocated may be the number of users that satisfy a predetermined communication quality, or users who are allocated frequency resources when performing PF (Proportional Fairness) scheduling based on FDMA. It may be a number, or may be determined based on a search space that is a resource used for transmission of control information and a data amount of control information (PDCCH: Physical Downlink Control Channel).

  The number-of-users control unit 303 outputs information indicating the number of users to which frequency resources are allocated at the determined next transmission opportunity as a communication parameter to the duplication rate determination unit 304. The duplication rate determining unit 304 determines the allowable duplication rate based on the information indicating the number of users. Here, the allowable duplication rate is the upper limit value of the duplication rate determined based on the communication parameter read from the user number control unit 303 in the duplication rate decision unit 404, and is the frequency resource used by each of the plurality of mobile station apparatuses. It is a ratio between the total number of frequency resources and the number of frequency resources that can be allocated.

The allowable duplication rate is determined by adding at least one of the plurality of mobile station apparatuses among the total number of frequency resources of the frequency resources used by each of the plurality of mobile station apparatuses and the number of frequency resources of the assignable frequency resources. It may be a ratio of the allocated frequency resources to the number of frequency resources.
The duplication rate determining unit 304 decides an allowable duplication rate, which is an index of the number of frequency resources that can be used by a plurality of mobile station apparatuses in an overlapping manner, based on communication parameters. Here, the communication parameter is the number of users who transmit data to the same slot used for reception by the base station apparatus 2a. The duplication rate determination unit 304 increases the number of users who transmit data to the same slot. As a result, the allowable duplication rate is increased. An example of a method for determining the allowable duplication rate in this embodiment is shown in FIG.

FIG. 10 shows a table T2 stored by the user number control unit 303 for determining the allowable duplication rate based on information indicating the number of users to which the frequency resource allocation is performed at the next transmission opportunity by the duplication rate determining unit 304 according to the present embodiment. It is a figure which shows an example.
As shown in the figure, the table T2 includes columns for each item of the number of users (Nu) to which the frequency resource is allocated and the allowable duplication rate. The table T2 is two-dimensional tabular data composed of rows and columns in which information on the allowable duplication rate is stored for each number of users (Nu) to which frequency resources are allocated.

  The number of users (Nu) to which the frequency resource in the first row is allocated is 0 ≦ Nu <NUSER1, and the allowable duplication rate corresponding thereto is NUSR_NOV1. The number of users (Nu) to which the frequency resource in the second row is allocated is NUSER1 ≦ Nu <NUSER2, and the allowable duplication rate corresponding to it is NUSR_NOV2. In addition, the number of users (Nu) to which the frequency resource in the third row is allocated is NUSER2 ≦ Nu <NUSER3, and the allowable duplication rate corresponding thereto is NUSR_NOV3. The number of users (Nu) to which the frequency resource in the fourth row is allocated is NUSER3 ≦ Nu, and the allowable duplication rate corresponding to it is NUSR_NOV4.

  However, it is 0 <NUSR1 <NUSR2 <NUSR3, NUSR_OV1 <= NUSR_OV2 <= NUSR_OV3 <= NUSR_OV4, NUSR_OV1 <NUSR_OV4. For example, NUSR1 = 5, NUSR2 = 10, NUSR3 = 15, NUSR_OV1 = 10%, NUSR_OV2 = 15%, NUSR_OV3 = 20%, and NUSR_OV4 = 25%.

  As the number of users to which frequency resources are allocated in the base station apparatus 2a increases, the number of frequency resources used per user decreases. In this case, even if the allowable duplication rate is increased and the frequency resources to be used are increased, the degradation of the frequency selective diversity gain is small. Therefore, by using the method for determining the allowable duplication rate described above, it is possible to appropriately control the allowable duplication rate. In the above example, there are three thresholds for changing the allowable duplication ratio, NUSR1, NUSR2, and NUSR3, but the present invention is not limited to this. A threshold value may be provided more finely, or a single threshold value may be provided.

FIG. 11 is a diagram illustrating an example of error rate characteristics by computer simulation when the number of antennas used for reception by the base station apparatus 2a according to the present embodiment is two and the number of mobile station apparatuses is two.
FIG. 12 is a diagram illustrating an example of error rate characteristics by computer simulation when the number of antennas used for reception by the base station apparatus 2a according to the present embodiment is two and the number of mobile station apparatuses is four. .

The simulation specifications indicate that the modulation scheme is QPSK and the error correction code is a turbo code coding rate of 1/2, and the non-orthogonal access scheme and the orthogonal access scheme based on FDMA are shown. Further, the number of FFT points is set to 2048, the number of assignable RBs is set to 100, and non-contiguous frequency resource allocation is performed.
In the orthogonal access scheme based on FDMA, the number of RBs used by one mobile station apparatus is a value obtained by equally distributing 100 RBs to each mobile station apparatus. When the number of mobile station apparatuses in FIG. 11 is 2, the number of RBs used by one mobile station apparatus is 50 RB, and when the number of mobile station apparatuses in FIG. 12 is 4, one mobile station apparatus is used. The number of RBs to be performed is 25 RBs.

In these figures, the horizontal axis represents the bandwidth usage rate B _u calculated by Expression (2). The error rate characteristic G301 of the orthogonal access scheme based on FDMA does not allow duplication in the frequency domain, and is always a characteristic when the band usage rate _Bu is 100%. That is, the error rate characteristics G301 and G401 of the orthogonal access scheme based on FDMA are error rate characteristics when the overlap rate O _sys = 0% calculated using Expression (1).
In the non-orthogonal access scheme, overlapping in the frequency domain is allowed, so the total number of RBs used by all mobile station apparatuses can be greater than 100. Therefore, the bandwidth usage rate B _u = 120% in the non-orthogonal access scheme is 120 RB in total as the number of RBs used by all mobile station apparatuses.

First, in the error rate characteristic G302 of the non-orthogonal access scheme in FIG. 11, up to about 120% of the bandwidth usage rate B _u can be realized with an error rate characteristic equivalent to the error rate characteristic G301 of the orthogonal access scheme based on FDMA.
On the other hand, in the error rate characteristic G402 of the non-orthogonal access scheme in FIG. 12, the band usage rate B _u can be realized with an error rate characteristic equivalent to the error rate characteristic G401 of the orthogonal access scheme based on FDMA up to about 130%.

When the bandwidth usage rate B _u in FIG. 11 is 120%, the overlap rate O _sys = 20% from the equation (1). In the case of the band usage rate B _u = 130% in FIG. 12, the overlap rate O _sys = 30% from the equation (1).
Therefore, in this example, the communication parameters of the number of users (Nu) to which the frequency resource of the table T2 in FIG. 10 is assigned can be set to NUSR1 = 2 and NUSR2 = 4, and NUSR_OV1 = 20% and NUSR_OV2 = 30%.
Therefore, if the duplication rate that can realize an error rate characteristic equivalent to that of the orthogonal access method is an allowable duplication rate, the larger the number of users, the higher the allowable duplication rate.

  Thus, according to the present embodiment, communication parameters can be determined so that good frequency utilization efficiency can be obtained. Since the base station apparatus 2a determines the allowable overlap rate based on the number of users to which the frequency resource is allocated, the allowable overlap ratio at which the system throughput can be maximized differs depending on the number of users to which the base station apparatus 2a allocates the frequency resource. The amount of improvement in system throughput by the orthogonal access method can be increased.

(Third embodiment)
Hereinafter, the third embodiment of the present invention will be described in detail with reference to the drawings.
In the first embodiment, a case has been described in which the allowable duplication rate is determined by the number of antennas used by the base station device 2 at the time of reception. In the present embodiment, a case will be described in which the allowable duplication rate is determined based on the number of clusters or the cluster size allocated non-continuously by the mobile station apparatuses 1-1 to 1-m.

  Since the configuration of the mobile station apparatuses 1-1 to 1-m according to the present embodiment is the same as that of the mobile station apparatuses 1-1 to 1-m according to the first embodiment, description thereof will be omitted.

FIG. 13 is a schematic block diagram illustrating an example of the configuration of the base station device 2b according to the present embodiment.
The base station apparatus 2 includes reception antennas 201-1 to 201-Nr, reception processing units 202-1 to 202-Nr, an antenna information management unit 203, a control information generation unit 206, a control information storage unit 207, Control information transmission unit 208, soft canceller unit 209, equalization unit 210, IDFT units 211-1 to 211-n, synthesis units 212-1 to 212-n, demodulation units 213-1 to 213-n Decoding units 214-1 to 214-n, soft symbol generation units 215-1 to 215-n, DFT units 216-1 to 216-n, and received signal soft replica generation units 217-1 to 217-n. And a cluster number control unit 403 and a duplication rate determination unit 404. Although the base station apparatus 2b has other generally known base station apparatus functions, illustration and description thereof are omitted.

  When the configuration of the base station apparatus 2b according to the present embodiment is compared with the base station apparatus 2 according to the first embodiment, the antenna information management unit 203 is deleted and a cluster number control unit 403 is added. Further, the method for determining the overlap rate in the overlap rate determining unit 404 is different from the method for determining the overlap rate of the overlap rate determining unit 204 in the first embodiment. Since other configurations are the same, description thereof is omitted.

  Reception processing units 202-1 to 202-Nr output reference signals separated from the received signals to scheduling unit 205 and cluster number control unit 403. The cluster number control unit 403 estimates the propagation path characteristics based on the reference signal separated from the received signal input from the scheduling section 205, and as communication parameters that each user can use for transmission based on the estimated propagation path characteristics. Determine the maximum number of clusters. The maximum number of clusters may be common to all users.

  Here, a cluster is, for example, a part of a frequency domain signal when frequency domain signals are allocated discontinuously. In single carrier transmission, a cluster is a partial spectrum obtained by dividing a single carrier spectrum. is there. In addition, when performing discontinuous frequency resource allocation in multicarrier transmission, in this specification, part of modulation symbols that are discontinuous is also referred to as a cluster.

  The maximum value of the number of clusters is determined by, for example, increasing the number of clusters, which degrades PAPR (Peak to Average Power Ratio) characteristics and CM (Cube Metric: Cubic Metric). The maximum number of clusters is determined so as not to be distorted during amplification in (PA: Power Amplifier). Note that the maximum number of clusters may be determined by determining the maximum number of clusters according to the frequency variation of the propagation path characteristics.

The cluster number control unit 403 outputs information indicating the determined maximum number of clusters to the duplication rate determination unit 404.
The duplication rate determination unit 404 determines the allowable duplication rate based on information indicating the maximum number of clusters input from the cluster number control unit 403. Here, the allowable duplication rate is the upper limit value of the duplication rate determined based on the communication parameter read from the cluster number control unit 403 in the duplication rate decision unit 404, and the frequency resource frequency used by each of the plurality of mobile station apparatuses This is the ratio between the total number of resources and the number of frequency resources that can be allocated.

  The allowable duplication rate is assigned to at least one of the plurality of mobile station devices among the total number of frequency resources of the frequency resources used by each of the plurality of mobile station devices and the number of frequency resources of the assignable frequency resources. It may be a ratio of the frequency resources to the number of frequency resources.

  The duplication rate determining unit 404 decides an allowable duplication rate, which is an index of the number of frequency resources that can be used by a plurality of mobile station apparatuses in an overlapping manner, based on communication parameters. Here, the communication parameter is the number of clusters or the cluster size used for reception by the base station apparatus 2b, and the duplication rate determination unit 404 increases the allowable duplication rate as the number of clusters or the cluster size increases. An example of a method for determining the allowable duplication rate in this embodiment is shown in FIG.

FIG. 14 is a diagram showing an example of a table T3 stored by the cluster number control unit 403 for the duplication rate determining unit 404 according to the present embodiment to determine the allowable duplication rate based on information indicating the maximum number of clusters. is there.
As shown in the figure, the table T3 includes columns for each item of the maximum number of clusters (Nc) and the allowable duplication rate. The table T3 is two-dimensional tabular data composed of rows and columns in which information on the allowable duplication rate is stored for each maximum value (Nc) of the number of clusters.

  The maximum value (Nc) of the number of clusters in the first row is 0 ≦ Nc <NCL1, and the allowable duplication rate corresponding to it is NCL_OV1. In addition, the maximum value (Nc) of the number of clusters in the second row is NCL1 ≦ Nc <NCL2, and the allowable duplication rate corresponding thereto is NCL_OV2. Further, the maximum value (Nc) of the number of clusters in the third row is NCL2 ≦ Nc <NCL3, and the allowable duplication rate corresponding to it is NCL_OV3. Further, the maximum value (Nc) of the number of clusters in the fourth row is NCL3 ≦ Nc, and the permissible overlap rate corresponding to it is NCL_OV4.

  However, 0 <NCL1 <NCL2 <NCL3, NCL_OV1 ≦ NCL_OV2 ≦ NCL_OV3 ≦ NCL_OV4, and NCL_OV1 <NCL_OV4. For example, NCL1 = 1, NCL2 = 2, NCL3 = 3, NCL_OV1 = 10%, NCL_OV2 = 15%, NCL_OV3 = 20%, NCL_OV4 = 25%, etc.

  As the maximum value of the number of clusters set by the base station device 2b increases, the frequency selection diversity gain obtained increases. Therefore, it is possible to expect an improvement in throughput characteristics by increasing the allowable duplication rate. As a result, by using the above-described method for determining the allowable duplication rate, it is possible to appropriately control the allowable duplication rate.

  In the present embodiment, the allowable duplication rate is increased as the maximum value of the number of clusters is increased. However, the allowable duplication rate may be determined by the minimum assignable cluster size. In this case, for example, the allowable duplication rate is increased as the minimum assignable cluster size is reduced. This is because, as the minimum assignable cluster size becomes smaller, the frequency selection diversity gain obtained becomes higher, so that the overlapping rate at which interference can be removed improves. Therefore, an improvement in throughput characteristics can be expected by increasing the allowable duplication rate. As a result, by using the allowable duplication rate determination method described above, it is possible to appropriately control the allowable duplication rate.

  As described above, according to the present embodiment, it is possible to improve cell throughput and improve frequency utilization efficiency during uplink data transmission in the non-orthogonal access scheme. Further, by determining the allowable duplication rate based on the maximum number of clusters or the cluster size set by the base station apparatus 2b, it is possible to increase the amount of improvement in system throughput by the non-orthogonal access method.

  In addition, you may make it implement | achieve part or all of the base station apparatus in embodiment mentioned above with a computer. In that case, the program for realizing the control function may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read by the computer system and executed. Here, the “computer system” is a computer system built in the base station apparatus and includes hardware such as an OS and peripheral devices.

  The “computer-readable recording medium” refers to a storage device such as a flexible medium, 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, a volatile memory inside a computer system that serves as a server or a client may be included that holds a program for a certain period of time.

  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.

  Moreover, you may implement | achieve part or all of the base station apparatus in embodiment mentioned above as integrated circuits, such as LSI (Large Scale Integration). Each functional block of the base station apparatus may be individually made into a processor, or a part or all of them may be integrated into a processor. Further, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. In addition, when an integrated circuit technology that replaces LSI appears due to the advancement of semiconductor technology, an integrated circuit based on the technology may be used.

  As described above, the embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the scope of the present invention. It is possible to

  Thus, according to each embodiment of the present invention, frequency resources used for data transmission are allocated to a plurality of mobile station apparatuses (1-1 to 1-m), and information on the frequency resources is assigned to the plurality of mobile stations. A base station device (2, 2a, 2b) that notifies a device (1-1 to 1-m) and simultaneously receives signals transmitted from the plurality of mobile station devices (1-1 to 1-m). Then, an overlap rate determination unit (204) that determines an allowable overlap rate that is an index of the number of frequency resources of the frequency resources that can be used by the plurality of mobile station devices (1-1 to 1-m) in an overlapping manner, based on communication parameters. 304, 404) and a scheduling unit (205-1 to 205-n) that determines the allocation of the frequency resource used by the plurality of mobile station apparatuses for the data transmission so as to satisfy the allowable duplication rate. Characterized in that it obtain.

  Further, the communication parameter is at least one of the number of antenna ports of antenna ports used for reception by the base station apparatus (2, 2a, 2b), the number of users of data transmitting data in the same slot, the number of clusters, or the cluster size. It is characterized by being one.

  Further, the communication parameter is the number of antenna ports used for reception by the base station apparatus (2), and the duplication rate determining unit (204) sets the allowable duplication rate as the number of antenna ports increases. It is characterized by increasing.

  The communication parameter is the number of users who transmit data to the same slot used for reception by the base station apparatus (2a), and the duplication rate determination unit (304) transmits data to the same slot. The allowable duplication rate is increased as the number of users increases.

  The communication parameter is the number of clusters or the cluster size used for reception by the base station device (2b), and the duplication rate determination unit (404) increases the number of clusters or the cluster size. It is characterized by increasing the allowable duplication rate.

The allowable duplication rate is a ratio of the total number of frequency resources of the frequency resources used by each of the plurality of mobile station apparatuses (1-1 to 1-m) and the number of frequency resources of the assignable frequency resources. There is,
It is characterized by.

  Further, the allowable duplication rate is the sum of the number of frequency resources of the frequency resources used by each of the plurality of mobile station apparatuses (1-1 to 1-m) and the number of frequency resources of the assignable frequency resources. It is a ratio of the frequency resources allocated to at least one of the plurality of mobile station apparatuses to the number of frequency resources.

  Also, frequency resources used for data transmission are allocated to a plurality of mobile station apparatuses (1-1 to 1-m), and information on the frequency resources is assigned to the plurality of mobile station apparatuses (1-1 to 1-m). And a radio communication system for simultaneously receiving signals transmitted from the plurality of mobile station apparatuses (1-1 to 1-m), wherein the plurality of mobile station apparatuses (1-1 to 1-m) A duplication rate determining unit (204, 304, 404) that determines an allowable duplication rate that is an index of the number of frequency resources that can be used in an overlapping manner based on communication parameters, and the plurality of mobile station devices (1-1 to 1-1) 1-m) includes a scheduling unit (205-1 to 205-n) that determines allocation of the frequency resource used for the data transmission so as to satisfy the allowable duplication rate.

  A duplication rate determining unit (204. 304, 304) that determines an allowable duplication rate that is an index of the number of frequency resources that can be used by a plurality of mobile station devices (1-1 to 1-m) in an overlapping manner. 404) and scheduling units (205-1 to 205) that determine the allocation of the frequency resources used by the plurality of mobile station apparatuses (1-1 to 1-m) for the data transmission so as to satisfy the allowable duplication rate. -N).

  Thereby, it is possible to determine the communication parameters so that good frequency utilization efficiency can be obtained. Further, since the allowable duplication rate is determined by the number of antennas used by the base station apparatus 2 for reception, the allowable duplication rate that can maximize the system throughput in the number of antennas used by the base station apparatus 2 is different. The amount of improvement in system throughput by the method can be increased.

  In addition, communication parameters can be determined so that good frequency utilization efficiency can be obtained. Since the base station apparatus 2a determines the allowable overlap rate based on the number of users to which the frequency resource is allocated, the allowable overlap ratio at which the system throughput can be maximized differs depending on the number of users to which the base station apparatus 2a allocates the frequency resource. The amount of improvement in system throughput by the orthogonal access method can be increased.

  In addition, cell throughput can be improved and frequency utilization efficiency can be improved during data transmission using the non-orthogonal access method in the uplink. Further, by determining the allowable duplication rate based on the maximum number of clusters or the cluster size set by the base station apparatus 2b, it is possible to increase the amount of improvement in system throughput by the non-orthogonal access method.

S1 Wireless communication system 1-1, 1-2, 1-1, 1-m Terminal apparatus 2, 2a, 2b Base station apparatus 101 Control information receiving unit 102 Encoding unit 103 Modulating unit 104 DFT unit 105 Frequency mapping unit 106 IFFT unit 107 reference signal multiplexing unit 108 transmission processing unit 109 transmission antenna 201-1, 201-Nr reception antenna 202-1, 202-k, 202-Nr reception processing unit 203 antenna information management unit 204 overlap rate determination unit 205 scheduling unit 206 control Information generation unit 207 Control information storage unit 208 Control information transmission unit 209 Soft canceller unit 210 Equalization unit 211-1, 211-k, 211-n IDFT unit 212-1, 212-k, 212-n Combining unit 213-1 213-k, 213-n Demodulator 214-1, 214-k, 214-n Decoder 215 1,215-k, 215-n soft symbol generation unit 216-1, 216-k, 216-n DFT unit 217-1, 217-k, 217-n received signal soft replica generation unit 2021-k received signal processing unit 2022-k Reference signal separation unit 2023-k FFT unit 2024-k Frequency demapping unit 303 User number control unit 304 Duplication rate determination unit 403 Cluster number control unit 404 Duplication rate determination unit

Claims (4)

A base station that allocates frequency resources to be used for data transmission to a plurality of mobile station apparatuses, notifies information about the frequency resources to the plurality of mobile station apparatuses, and simultaneously receives signals transmitted from the plurality of mobile station apparatuses A device,
A duplication rate determining unit that determines an allowable duplication rate that is an index of the number of frequency resources of the frequency resources that can be used by the plurality of mobile station devices in an overlapping manner, based on communication parameters;
A scheduling unit that determines allocation of the frequency resource used by the plurality of mobile station apparatuses for the data transmission so as to satisfy the allowable duplication rate;
Equipped with a,
The base station is characterized in that the communication parameter is at least one of the number of antenna ports of antenna ports used for reception by the base station apparatus, the number of users transmitting data in the same slot, the number of clusters, or the cluster size. Station equipment. The allowable duplication rate is a ratio between the total number of frequency resources of frequency resources used by each of the plurality of mobile station apparatuses and the number of frequency resources of frequency resources that can be allocated;
The base station apparatus according to claim 1. The allowable duplication rate is allocated to at least one of the plurality of mobile station apparatuses among the total number of frequency resources of frequency resources used by each of the plurality of mobile station apparatuses and the number of frequency resources of allocatable frequency resources. The ratio of the frequency resource assigned to the number of frequency resources ,
The base station apparatus according to claim 1. A duplication rate determining unit that determines an allowable duplication rate, which is an index of the number of frequency resources of a frequency resource that can be used by multiple mobile station devices,
A scheduling unit that determines allocation of the frequency resource used by the plurality of mobile station apparatuses for data transmission so as to satisfy the allowable duplication rate;
With
The communication parameter is at least one of the number of antenna ports of the antenna port used for reception by the base station apparatus, the number of users transmitting data in the same slot, the number of clusters, or the cluster size.
Processor.

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