JP5160305B2 - Spatial / frequency division multiple access apparatus and spatial / frequency division multiple access method - Google Patents

Description

  The present invention relates to a space / frequency division multiple access apparatus and a space / frequency division multiple access method for performing MIMO (Multiple Input Multiple Output) communication for transmitting and receiving signals of a plurality of channels in the same frequency band simultaneously using a plurality of antennas. About.

  In order to cope with various large-capacity services associated with the spread of optical access and the like in recent years, it is required to improve the transmission speed of wireless communication. Since the transmission speed is proportional to the occupied frequency band, the transmission speed can be improved by expanding the frequency band. However, since the actual frequency resources are limited, there is a limit to the expansion of the frequency band. Further, as a method for improving the transmission speed without increasing the frequency band, a modulation scheme having a large modulation multi-level number such as QPSK that transmits 2 bits per symbol or 64QAM that transmits 6 bits per symbol is used. There is a way. However, since the distance between signal points decreases as the number of multi-values increases, errors due to noise and errors due to hardware characteristics tend to occur, and a high signal-to-noise ratio is required to ensure good communication quality. Thus, it is difficult to greatly improve the transmission speed by this method.

  Therefore, space division multiple access has been proposed in which the frequency utilization efficiency is improved and the transmission rate is improved without using these methods. In space division multiple access, as shown in FIG. 6, the signal transmitted from the antenna of the transmitter is weighted by phase and amplitude, or the signal received by the antenna of the receiver is weighted by phase and amplitude. Thus, transmission signals 1, 2, and 3 to each receiver using the same frequency are spatially separated and can be transmitted simultaneously. As a result, the total transmission rate when the space division multiple access is performed can be increased as compared with the transmission rate when the space division multiple access is not performed.

  FIG. 7 shows a configuration example of a conventional space division multiple access apparatus. Here, a configuration in which space division multiple access is performed between a transmitter 21 equipped with two antennas and two receivers 22a and 22b equipped with one antenna will be described. In this configuration, it is assumed that OFDM (Orthogonal Frequency Division Multiplexing) modulation that transmits signals using a plurality of subcarriers is also used. Further, although this configuration shows a case where the number of subcarriers is 2, an actual system uses several tens to several thousand subcarriers.

  The transmission data unit 1a holds transmission data of the system 1 transmitted from the transmitter 21 to the receiver 22a. The transmission data unit 1b holds transmission data of the system 2 that is transmitted from the transmitter 21 to the receiver 22b. Transmission data of each system is distributed to each subcarrier by distribution units 2a and 2b. Note that subcarriers used by transmission data of each system are subcarrier 1 and subcarrier 2, and share the subcarriers to be used. The transmission data distributed by the distribution units 2a and 2b is subcarrier modulated by the subcarrier modulation units 9a and 9b. For subcarrier modulation, various modulation schemes are used according to the system design, such as BPSK that transmits 1 bit per symbol and 256 QAM that transmits 8 bits per symbol.

  Here, A is a transmission symbol after system 1, subcarrier 1, and subcarrier modulation at a certain time, and B is a transmission symbol after system 2, subcarrier 1, and subcarrier modulation. The transmission signal d composed of these is

It is expressed.
The transmission signal d is adjusted in phase and amplitude by the weight multiplier 4a so that space division multiple access is possible, that is, the receivers 22a and 22b can receive the symbols A and B, respectively. The weight of the weight multiplication unit 4a is calculated by the weight calculation unit 11 with reference to the propagation parameter between the transmitting and receiving antennas held by the propagation parameter estimation unit 12. Similarly, for the transmission signal corresponding to the subcarrier 2, the weight / multiplier 4b adjusts the phase and amplitude.

Here, the definition of the propagation parameter and the operation of the propagation parameter estimation unit 12 will be described. In this configuration, signals are transmitted from the two transmission antennas 6a and 6b, and each transmission signal passes through different spaces, receives different fluctuations, and is received by the two reception antennas 7a and 7b. Propagation parameters h ₁₁ from transmit antenna 6a to the output antenna 7a, transmits propagation parameters of h ₂₁ from the antenna 6a to the output antenna 7b, h ₁₂ a propagation parameter from the transmitting antenna 6b to the output antenna 7a, the output from the transmission antenna 6b the propagation parameters of the antenna 7b and h _22, the propagation parameters H from these

It is expressed. The propagation parameter H has the number of rows of the number of reception antennas and the number of columns of the number of transmission antennas, and in the case of the configuration of FIG.

  When reverse links from the receivers 22a and 22b exist, the propagation parameter estimation unit 12 estimates H from the reverse link signal. Alternatively, the receivers 22a and 22b estimate the results, separately notify the propagation parameter estimation unit 12 of the results, and the propagation parameter estimation unit 12 holds the results.

If a signal is transmitted without using the weight multipliers 4a and 4b, and x is a signal from each transmission antenna, x is received by each reception antenna, and x and H are received from the reception antenna. The signal y is
y = Hx (1)
It is expressed. In this case, x = d based on the above-described conditions.

  Here, a weight division is adjusted in the receiver, and a signal transmitted from the received signal is extracted, thereby realizing space division multiple access. Note that typical calculation methods for separating a plurality of different transmission signals by a plurality of antennas include a method by Zero Forcing in Patent Document 1 and Non-Patent Document 1, a method by Maximum Likelihood Detection in Non-Patent Document 2, and a non-patent document. There is a method such as 3 Minimum Mean Square Error.

  In addition, the weight division is adjusted in the transmitter, and as a result, a desired transmission signal is received by the receiving antenna of each receiver, thereby realizing space division multiple access. In FIG. 7, the operation of the weight calculation unit 11 responsible for this calculation will be described based on the above-described method by Zero Forcing. For simplicity, signal noise display is omitted.

The weight calculation unit 11 calculates a weight with reference to the propagation parameter matrix H obtained from the propagation parameter estimation unit 12. If the weight obtained here is a matrix C, the transmission signal x after weight application is
x = Cd (2)
It is expressed. From equations (1) and (2), it can be seen that if the weight C is an inverse matrix of H, a desired result can be obtained. Generalizing this matrix calculation, weight C uses a pseudo inverse matrix,
C = H ^* (HH ^* ) ⁻¹ (3)
It is expressed. Here, * represents transposition of the matrix, and -1 represents normal inverse matrix calculation.

  The weight C obtained by this calculation is multiplied by the transmission signal in the weight multipliers 4a and 4b. The output of the weight multiplication unit 4a represents a signal transmitted from the transmission antennas 6a and 6b using the subcarriers 1 of the systems 1 and 2. Similarly, the output of the weight multiplication unit 4b represents a signal transmitted from the transmission antennas 6a and 6b using the subcarriers 2 of the systems 1 and 2.

The outputs of the weight multipliers 4a and 4b are subjected to IFFT computation by IFFT (Inverse Fast Fourier Transform) computation units 5a and 5b, respectively, and then a guard interval is added to convert them into OFDM signals. This OFDM signal is transmitted from the transmitting antennas 6a and 6b, and reaches the receiving antennas 7a and 7b after receiving a fluctuation of the propagation parameter matrix H in space. At this time, the receivers 22a and 22b receive desired signals, respectively, and the receiving units 8a and 8b restore the transmission symbols A and B. In this way, space division multiple access is realized.
Japanese Patent No. 3631698 QHSpencer, et al., "An introduction to the multi-user MIMO downlink", IEEE Commun. Mag., Oct. 2004 R.van Nee, et al., "Maximum Likelihood decoding in a space division multiplexing system", Proc. IEEE VTC 2000, pp. 6-10, May 2000 A. Benjebbour, et al., "A Semi-Adaptive MNSE Weights Generation Approach for Ordered Successive Detection in MIMO Systems", IEICE Trans.Commun., Vol.E87-B, No.2, Feb.2004

  In order to ideally perform space division multiple access, it is necessary to have a good propagation environment between transmitting and receiving antennas and to form a MIMO transmission path for a plurality of receiving antennas. However, actual radio wave propagation does not always satisfy these conditions.

  Here, the propagation environment between the transmitting and receiving antennas, which is the first condition, will be described. In wireless communication, signals transmitted from a transmitting antenna generally pass through various paths due to obstacles in the propagation path, and after being reflected, arrive at the receiving antenna. These signals with different delay times are combined. Receive. At this time, since each signal is synthesized with a different phase relationship for each frequency, an amplitude deviation occurs in the band. This phenomenon is called frequency selective fading.

  As shown in FIG. 8, the level of frequency selective fading is greatly different for each frequency. The horizontal axis in FIG. 8 corresponds to the subcarrier number of the OFDM signal, that is, the frequency. The vertical axis represents the instantaneous signal power to noise power ratio (hereinafter referred to as “C / N”) at the receiver, which corresponds to the relative value of the received power level when the expected value of the noise power of each subcarrier is assumed to be constant. To do. When single carrier transmission is performed using the entire band of FIG. 8, the bit error rate deteriorates due to the amplitude deviation in the band. On the other hand, since the OFDM signal is transmitted by dividing the band of FIG. 8 into a plurality of narrowband signals (subcarriers), the amplitude deviation generated in each subcarrier is small, and the amplitude is uniform for each subcarrier. The bit error rate due to the amplitude deviation in the band can be improved.

  However, as shown in FIG. 8, the received power levels of the subcarriers in the frequency selective fading environment are greatly different. When a signal is transmitted using a single subcarrier modulation scheme for a plurality of subcarriers in such a frequency selective fading propagation environment, the bit error rate BER of a subcarrier having a low C / N is extremely deteriorated. As a result, there is a possibility that the entire communication cannot be performed.

  Next, the formation of the MIMO transmission path as the second condition will be described. In order to perform space division multiple access, as shown in FIG. 6, it is ideal that an independent transmission path is formed for each terminal and only necessary information is transmitted. On the other hand, in the actual propagation environment, as a result of calculating the weight for avoiding interference, the reception level may be lowered depending on the phase condition of the signal at the receiving antenna of the receiver. This also occurs when subcarriers with a good propagation environment are used. When space division multiple access is performed in such a propagation environment, there is a problem that sufficient received power for satisfying the error rate of the receiver cannot be obtained, and in some cases the signal cannot be restored. In order to overcome this, there is a method of increasing the transmission power. However, since the transmission power is generally finite, it cannot always be solved by increasing the transmission power.

  As described above, the space division multiple access apparatus performs MIMO transmission in a frequency selective fading propagation environment when performing communication using subcarriers with poor propagation environment or in a propagation environment in which it is difficult to form an independent transmission path. In some cases, the bit error rate in the receiver deteriorates.

  The present invention relates to a space / frequency division multiple access apparatus and a space / frequency in which a transmission rate is high and a bit error rate is reduced in a frequency selective fading propagation environment or a propagation environment where subcarriers are difficult to form an independent transmission path. An object is to provide a divisional multiple access method.

  A first invention is a space in which a space and a frequency are divided and connected between one transmitter having a plurality of transmission antennas and one or more receivers each having one or more reception antennas and a reception unit. -In the frequency division multiple access device, the transmitter inputs transmission data for each system from the transmission data section that holds transmission data to be transmitted to each receiving section of the receiver for each system, and transmits the transmission data for each system. A distribution unit that distributes data to one or more subcarriers that data occupies and a transmission bit that each subcarrier transmits under the condition that the transmission data distributed to each subcarrier is input from the distribution unit and the required communication quality is satisfied The subcarrier modulation / power allocation unit that determines the number and transmission power, and one or more transmission data using the same subcarrier among the outputs of the subcarrier modulation / power allocation unit The same number of weight multipliers as the number of subcarriers to be multiplied by the weights, and among the outputs of the weight multipliers, the signals of all the subcarriers transmitted from one transmission antenna are subjected to inverse Fourier transform (IFFT transform), The IFFT operation unit connected to the transmission antenna, the propagation parameter estimation unit for estimating the propagation parameter for each subcarrier between each transmission antenna and each reception antenna, and the allocation result of the subcarrier modulation / power allocation unit, A subcarrier allocating unit that determines the subcarrier used by each transmission data and notifies the distribution unit according to the number of transmission data lines to be transmitted, the requested bit rate, the transmission power of the transmission antenna, and the changing propagation parameter, In order to perform space division multiplexing from the output of the propagation parameter estimation unit according to the subcarrier allocation of the subcarrier allocation unit Determining the weight of each sub-carrier to be transmitted from the transmitting antenna, and a weight calculation unit that notifies the subcarrier modulation and power allocation unit and a weight multiplying unit.

  Here, the weight calculation unit is configured to calculate a weight by which a corresponding receiving unit can restore transmission data of each system transmitted by space division multiplexing (for example, forming an orthogonal beam).

The subcarrier allocating unit of the spatial / frequency division multiple access apparatus of the first invention refers to the number of allocatable bits from the subcarrier modulation / power allocating unit and determines the same subcarrier combination occupied by transmission data of each system. As an objective function that maximizes the total bit rate of transmission data of all systems when an unknown variable is entered and a value is input to the unknown variable, the transmission of each system is obtained by obtaining a solution of the unknown variable using a genetic algorithm. Subcarrier allocation is performed so that data occupies the same subcarrier .
In addition, the subcarrier allocation unit of the spatial / frequency division multiple access apparatus of the first invention refers to the number of allocatable bits from the subcarrier modulation / power allocation unit, and determines the same subcarrier occupied by transmission data of each system. As an objective function that satisfies the required bit rate of the transmission data of each system when the combination is an unknown variable and a value is input to the unknown variable, a solution of the unknown variable is obtained using a genetic algorithm. Subcarrier allocation is performed so that transmission data occupies the same subcarrier .
In addition, the subcarrier allocation unit of the spatial / frequency division multiple access apparatus of the first invention refers to the number of allocatable bits from the subcarrier modulation / power allocation unit, and determines the same subcarrier occupied by transmission data of each system. The genetic algorithm is used as an objective function that maximizes the total bit rate of the transmission data of all systems when the combination is an unknown variable and a value is input to the unknown variable, and satisfies the required bit rate of the transmission data of each system. By obtaining solutions of unknown variables, subcarrier allocation is performed so that the transmission data of each system occupies the same subcarrier .

Further, the subcarrier allocating unit of the space / frequency division multiple access apparatus of the first invention refers to the required transmission power from the subcarrier modulation / power allocating unit and combines the same subcarriers occupied by transmission data of each system it was an unknown variable, as an objective function that minimizes the required transmit power satisfying the required bit rate of the transmission data of each system when the input values to unknown variables, to obtain a solution of unknown variables using genetic algorithm Thus, subcarrier allocation is performed so that transmission data of each system occupies the same subcarrier.

  Further, the space / frequency division multiple access device of the first invention may be configured such that one receiver includes a plurality of reception antennas and reception units, and the receiver receives transmission data of one or a plurality of systems. .

  In the spatial / frequency division multiple access apparatus of the first invention, a plurality of transmission antennas are installed at spatially separated positions, each transmission antenna forms a different service area for each subcarrier, and a subcarrier allocation unit May be configured to select a combination of subcarriers in which transmission data of each system does not interfere.

The second invention is a space in which space and frequency are divided and connected between one transmitter having a plurality of transmitting antennas and one or more receivers each having one or more receiving antennas and a receiving unit. In the frequency division multiple access method, the transmitter includes a transmission data unit, a distribution unit, a subcarrier modulation / power allocation unit, a weight multiplication unit, an IFFT calculation unit, a propagation parameter estimation unit, a subcarrier allocation unit, and a weight calculation unit. comprising, transmitting data unit, the transmission data to be transmitted to the receiving unit of the receiver held by the system, the distribution unit receives the transmission data of each channel from the transmission data unit, transmission data for each line occupies 1 satisfaction and dispensing steps, the sub-carrier modulation and power allocation unit receives the transmission data distributed to each subcarrier in distributing step, the required communication quality distributed to more subcarriers That under conditions, and the sub-carrier modulation and power allocation step each subcarrier to determine the transmission bit rate and transmission power to be transmitted, the weight multiplication unit is, in the output obtained by the subcarrier modulation and power allocation step, the same a weight multiplication step of multiplying a weight to transmission data 1 or the use of sub-carrier of, IFFT calculation unit, of the output obtained by the weight multiplication step, of all the sub-carrier to be transmitted from one transmit antenna inverse Fourier transformation signal (IFFT conversion), the propagation parameter estimation and IFFT calculation step of connecting the respective transmit antennas, the propagation parameter estimation unit, which estimates the propagation parameters for each sub-carrier between each transmit antenna and each receive antenna a step, the subcarrier allocation section, allocation of subcarrier modulation and power allocation step In accordance with the results, the subcarriers used by each transmission data are determined according to the number of transmission data lines to be transmitted to the reception unit, the required bit rate, the transmission power of the transmission antenna, and the changing propagation parameter, and are distributed The subcarrier allocation step to be notified, and the weight calculation unit according to the subcarrier allocation in the subcarrier allocation step, for each subcarrier transmitted from each transmission antenna for space division multiplexing from the output obtained in the propagation parameter estimation step A weight calculation step of determining a weight and notifying the subcarrier modulation / power allocation unit and the weight multiplication unit is executed.

In the subcarrier allocation step of the space / frequency division multiple access method of the second invention, a combination of the same subcarriers occupied by transmission data of each system with reference to the number of allocatable bits from the subcarrier modulation / power allocation unit Is an unknown variable, and as a target function to maximize the total bit rate of transmission data of all systems when a value is input to the unknown variable, the transmission of each system is obtained by using a genetic algorithm to obtain the solution of the unknown variable. Subcarrier allocation is performed so that data occupies the same subcarrier.
Also, referring to the number of allocatable bits from the subcarrier modulation / power allocation unit, the combination of the same subcarriers occupied by transmission data of each system is set as an unknown variable, and transmission of each system when a value is input to the unknown variable As an objective function that satisfies the required bit rate of data, a solution of an unknown variable is obtained using a genetic algorithm, so that subcarriers are allocated so that transmission data of each system occupies the same subcarrier .
Also, referring to the number of allocatable bits from the subcarrier modulation / power allocation unit, the same subcarrier combination occupied by transmission data of each system is set as an unknown variable, and transmission of all systems when a value is input to the unknown variable By obtaining the solution of unknown variables using a genetic algorithm as an objective function that maximizes the total bit rate of the data and satisfies the required bit rate of the transmission data of each system, the transmission data of each system has the same sub- Subcarriers are allocated so as to occupy carriers .
Also, referring to the required transmission power from the subcarrier modulation / power allocation unit, the combination of the same subcarriers occupied by the transmission data of each system is an unknown variable, and the transmission data of each system when a value is input to the unknown variable As an objective function for minimizing the required transmission power that satisfies the required bit rate of the Make assignments.

  The spatial / frequency division multiple access apparatus of the present invention refers to the number of bits that can be transmitted by the subcarrier allocation unit or the required transmission power, and the transmission data system so that the number of transmission bits increases and the required transmission power decreases. It is possible to adaptively select a set of reception antennas for each number and subcarrier according to changes in the propagation environment, and to adjust the number of transmission bits and transmission power of each subcarrier so as to satisfy the required quality.

  The subcarrier allocating unit of the space / frequency division multiple access apparatus of the present invention selects a receiving antenna that is a set of propagation parameters that increases the number of transmittable bits for each subcarrier, thereby achieving excellent bit error. Communication with a high bit rate can be performed while maintaining the rate.

  In addition, the subcarrier allocating unit of the spatial / frequency division multiple access apparatus of the present invention selects a reception antenna that is a set of propagation parameters that reduces the required transmission power while satisfying the required number of transmission bits for each subcarrier. By doing so, it is possible to perform communication with reduced transmission power while maintaining an excellent bit error rate.

  Furthermore, the space / frequency division multiple access apparatus of the present invention can increase the bit rate per receiver by providing one receiver with a plurality of receiving antennas and receiving units.

  Furthermore, the space / frequency division multiple access apparatus of the present invention can increase the bit rate by forming a plurality of independent communication paths by selecting a pair of transmission / reception antennas having propagation environments that do not easily interfere with each other. .

(First embodiment)
FIG. 1 shows a first embodiment of the space / frequency division multiple access apparatus of the present invention. Here, a configuration in which a space / frequency division multiple connection is made between a transmitter 21 equipped with two antennas and two receivers 22a and 22b equipped with one antenna will be described. In this configuration, OFDM modulation for transmitting a signal using a plurality of subcarriers effective for frequency selective fading is used together, and the maximum number of subcarriers is set to 2 for simplicity.

  In the figure, transmission data sections 1a and 1b, distribution sections 2a and 2b, weight multiplication sections 4a and 4b, IFFT calculation sections 5a and 5b, transmission antennas 6a and 6b, reception antennas 7a and 7b, reception sections 8a and 8b, weight calculation The unit 11 and the propagation parameter estimation unit 12 are the same as those in the conventional configuration shown in FIG.

  The feature of this embodiment is that the subcarrier modulation units 9a and 9b of the conventional space division multiple access apparatus are replaced with subcarrier modulation / power allocation units 3a and 3b, and the communication quality is satisfied according to the output of the weight calculation unit 11. As described above, the number of transmission bits and transmission power of each subcarrier are adjusted, and the information is given to the newly provided subcarrier allocation unit 10, and the distribution units 2a and 2b refer to the subcarrier allocation unit 10 to transmit the transmission bit rate. The subcarriers used by each system are selected so that the number increases.

Hereinafter, an operation example according to the configuration of the present embodiment will be described.
The transmission data unit 1a holds transmission data of the system 1 transmitted from the transmitter 21 to the receiver 22a. The transmission data unit 1b holds transmission data of the system 2 that is transmitted from the transmitter 21 to the receiver 22b. The transmission data of each system is distributed to the subcarriers to be used by the distribution units 2a and 2b with reference to the subcarrier allocation unit 10. Here, distribution section 2a uses subcarrier 1 and subcarrier 2, and distribution section 2b uses only subcarrier 1. The subcarrier allocation matrix D instructed by the subcarrier allocation unit 10 to correspond to this is:

It is expressed as Here, each column represents a transmission data system, each column represents a subcarrier number, and “1” indicates that the subcarrier is used and “0” indicates that the subcarrier is not used. A method for determining the subcarrier allocation matrix D will be described later.

First, the operation of the weight calculation unit 11 will be described. The weight calculation unit 11 refers to the propagation parameter matrix H obtained from the propagation parameter estimation unit 12 and the subcarrier allocation matrix D output from the subcarrier allocation unit 10, and assigns weights so that space division multiple access is possible. calculate. The weight C (1) of subcarrier 1 and the weight C (2) of subcarrier 2 obtained here are obtained by using a pseudo inverse matrix.
C (1) = H (1) ^* (H (1) H (1) ^* ) ^-1
C (2) = H (2) ^* (H (2) H (2) ^* ) ^-1 ... (4)
It is represented by Here, * represents transposition of the matrix, and -1 represents normal inverse matrix calculation. H (1) and H (2) are composed of propagation parameters related to the receiving antenna used by each subcarrier,

It is expressed.
The transmission bits distributed by distribution units 2a and 2b are subcarrier modulated by subcarrier modulation / power distribution units 3a and 3b. Here, the error rates required by the receivers 22a and 22b are satisfied by referring to the weights C (1) and C (2) of the subcarriers and the propagation parameters H (1) and H (2). The modulation method and power are determined.

  The operation of the subcarrier modulation / power distribution units 3a and 3b will be described with reference to FIG. Here, modulation method determination and transmission power allocation according to the Greedy water-filling algorithm are shown, but other methods may be used, a method of adjusting only the transmission power with the modulation method fixed, or transmission You may use the method of adjusting only a modulation system by fixing electric power. For subcarrier modulation, QPSK that transmits 2 bits per symbol, 16 QAM that transmits 4 bits per symbol, and 64 QAM that transmits 6 bits per symbol are used.

  First, the transmission power P (n) allocated to each subcarrier is initialized to 0, and the modulation scheme number M (n) is set to 0 (S1). Here, n is a subcarrier number and is an integer of 1 to N. N is the number of subcarriers used. In this embodiment, system 1 is 2 and system 2 is 1. No bit is assigned to subcarrier n when M (n) is 0, 2 bits are assigned (QPSK) when 1 is assigned, 4 bits are assigned (16 QAM), 2 is assigned with 6 bits (64 QAM) ).

Next, the additional power ΔP ₀ (n) required for transmitting 2 bits more than the current state for each subcarrier, that is, for increasing the modulation scheme by one step, is calculated based on the following equation (S2).
ΔP ₀ (n) = {R (M (n) +1) −R (M (n))} / {ΣH (n) C (n)} ²
ΔP (n) = ΔP ₀ (n) Σ | C (n) | ²
Here, R (M (n)) is the received power required for the modulation scheme number M (n), and ΣH (n) C (n) is the sum of components related to the target receiving antenna for each subcarrier. Represent. ΔP ₀ (n) is a level at the output of the subcarrier modulation / power allocation units 3a and 3b, and ΔP (n) is obtained by converting this into power output from the transmission antenna. The propagation parameter H (n) is a configuration estimated from the reverse link training signal transmitted from the receiver, and is assumed to be known in the transmitter.

  Next, the minimum value of the added powers ΔP (1) to ΔP (N) of each subcarrier obtained in step S2 is searched for ΔPmin and the subcarrier number nmin at that time (S3). Note that arg (min (ΔP (n))) in step S3 is a function that outputs n in ΔPmin.

  Next, the sum total (P (n)) of transmission powers P (1) to P (N) allocated to each subcarrier so far and the sum of ΔPmin searched in step S3 are compared with the maximum transmission power Pmax. (S4) If sum (P (n)) + ΔPmin exceeds Pmax, this bit cannot be assigned and the process is terminated. On the other hand, if sum (P (n)) + ΔPmin does not exceed Pmax, a modulation scheme number and power are assigned to the subcarrier nmin that minimizes the added power. That is, ΔPmin is increased to the transmission power P (nmin) of the subcarrier nmin, 1 is increased to the modulation scheme number M (nmin) (S5), and the procedure from step S2 is repeated again. As a result, the modulation scheme number (M (nmin) +1) and the transmission power (P (nmin) + ΔPmin) are assigned to the subcarrier number nmin while the quality is always kept constant.

  For the maximum transmission power Pmax, the total transmission power may be divided by the number of systems, or different power may be allocated for each user within a range not exceeding the total transmission power. At this stage, the subcarriers whose modulation scheme number M (n) remains the initial value 0 have the transmission power P (n) of 0, and are the subcarriers to which no transmission bits and transmission power are allocated.

  Here, a transmission symbol at the output of system 1, subcarrier 1, subcarrier modulation / power allocation unit 3a at a certain time is A, and a transmission symbol at the output of system 2, subcarrier 1, subcarrier modulation / power allocation unit 3b Is B.

  These signals are multiplied by the weight C previously obtained by the weight calculator 11, and the phase and amplitude are adjusted. The output of the weight multiplication unit 4a represents a signal transmitted from the transmission antennas 6a and 6b using the subcarriers 1 of the systems 1 and 2. Similarly, the output of the weight multiplication unit 4 b represents a signal transmitted from the transmission antennas 6 a and 6 b using the subcarrier 2 of the system 1.

  The outputs of the weight multipliers 4a and 4b are subjected to IFFT computations by the IFFT computation units 5a and 5b, respectively, are added with a guard interval, and are converted into OFDM signals. This OFDM signal is transmitted from the transmitting antennas 6a and 6b, and reaches the receiving antennas 7a and 7b after receiving a fluctuation of the propagation parameter matrix H in space. At this time, the receivers 22a and 22b receive desired signals, respectively, and the receiving units 8a and 8b restore the transmission symbols A and B.

  The subcarrier allocation unit 10 refers to the allocation result performed by the subcarrier modulation / power allocation units 3a and 3b with respect to the designated subcarrier allocation matrix D, and maximizes the total bit rate of transmission signals of each system. The subcarrier allocation matrix D is adjusted as described above. Further, the subcarrier allocation matrix D may be adjusted so as to satisfy the required bit rate of the transmission signal of each system. Further, the subcarrier allocation matrix D may be adjusted so that the increase in the total bit rate of the transmission signals of all systems and the required bit rate of the transmission signals of each system are compatible. Alternatively, the signal may be transmitted after the determination of the subcarrier allocation matrix D in the subcarrier allocation unit 10 and the notification of the number of bits in the subcarrier modulation / power allocation units 3a and 3b are repeatedly performed.

  Up to this point, an example has been shown in which one transmitter 21 equipped with two transmission antennas and two receivers 22a and 22b equipped with one reception antenna are shown. Even if there are one or three or more receivers, the same applies. In addition, the number of receiving antennas used for a series of calculations smaller than the number of receiving antennas, that is, the number of transmission systems may be determined in advance. As described above, communication with a high transmission rate and an excellent bit error rate can be performed.

(Second Embodiment)
The second embodiment of the space / frequency division multiple access apparatus of the present invention differs from the configuration of the first embodiment shown in FIG. 1 in that the operational rules of the subcarrier modulation / power allocation units 3a and 3b are different. It is characterized by operating so as to satisfy the required bit rate. Operations other than the subcarrier modulation / power allocation units 3a and 3b are the same as those in the first embodiment.

  The operation of the subcarrier modulation / power distribution units 3a and 3b of this embodiment will be described with reference to FIG. Here, modulation method determination and transmission power allocation according to the Greedy water-filling algorithm are shown, but other methods may be used, a method of adjusting only the transmission power with the modulation method fixed, or transmission You may use the method of adjusting only a modulation system by fixing electric power.

  In FIG. 3, steps S11 to S13 are the same as steps S1 to S3 of the first embodiment shown in FIG. 2, and after step S13, the modulation scheme number and power are added to the subcarrier nmin where the added power is minimized. Assign. That is, ΔPmin is increased to the transmission power P (nmin) of the subcarrier nmin, and 1 is increased to the modulation method number M (nmin) (S14). By performing this calculation, power and modulation schemes can be assigned next while maintaining the quality constant.

  Next, the total sum (M (n)) of the modulation scheme numbers M (1) to M (N) allocated to the subcarriers so far is compared with the required bit rate Mmax (S15), and sum (M ( If n)) does not exceed Mmax, the procedure from step S12 is repeated again. Then, the process ends when sum (M (n)) exceeds Mmax. At this stage, the subcarriers whose modulation scheme number M (n) remains the initial value 0 have the transmission power P (n) of 0, and are the subcarriers to which no transmission bits and transmission power are allocated. As described above, communication with a high transmission rate and an excellent bit error rate can be performed.

(Third embodiment)
The third embodiment of the space / frequency division multiple access apparatus of the present invention is characterized in that a genetic algorithm is introduced into the operation of the subcarrier allocation unit 10 in the configuration of the first embodiment shown in FIG. . Operations other than the subcarrier allocation unit 10 are the same as those in the first embodiment or the second embodiment.

The operation of the subcarrier allocation unit 10 of this embodiment will be described with reference to FIG.
The subcarrier allocation unit 10 has a plurality of subcarrier allocation matrices D shown in the first embodiment therein (S21). Here, _two subcarrier allocation matrices D ₁ and D ₂ are held, and these are candidates for subcarrier allocation. The initial values of the subcarrier allocation matrices D ₁ and D ₂ are given as all zeros, all ones, or 0 and 1 random numbers. The elements of the subcarrier allocation matrices D ₁ and D _{2 at} the initial value may be the same or different.

Next, the performance of each of the subcarrier allocation matrices D ₁ and D ₂ is evaluated (S22). That is, the calculation result of the subcarrier modulation / power allocation units 3a and 3b when D ₁ or D ₂ is given to the distribution units 2a and 2b in FIG. 1 (the required number of bits in the first embodiment, the second embodiment Required power). The result for D ₁ is E ₁ and the result for D ₂ is E ₂ . Here, it is determined whether or not E ₁ or E ₂ satisfies the required number of bits or power (S23). If satisfied, the process is terminated. Proceed to step.

Next, the subcarrier allocation matrices D ₁ and D ₂ are selected (S24). This is to make it easier for the next generation to remain probable from the previous evaluation result. Here, D ₂ is deleted from the original D ₁ and D ₂ , and D ₁ is duplicated to newly generate D ₁ and D ₂ .

Next, crossover of new subcarrier allocation matrices D ₁ and D ₂ is performed (S25). This is an exchange of elements between matrices, and is generated stochastically. Here, the components c and d constituting the original D ₁ and the components g and h constituting D ₂ are exchanged to newly generate D ₁ and D ₂ .

Next, new subcarrier allocation matrices D ₁ and D ₂ are mutated (S26), and the process returns to step S22. This is a change in the elements in the matrix and occurs probabilistically. Here, bit inversion means that component c (for example, 0) constituting D ₁ is bit-inverted, and a new D _{1 in} which component c becomes 1 is generated.

  The processing from step S22 to step S26 is repeated until a required bit number or power condition is achieved. As described above, communication with a high transmission rate and an excellent bit error rate can be performed.

(Fourth embodiment)
FIG. 5 shows a fourth embodiment of the space / frequency division multiple access apparatus of the present invention.
In the present embodiment, as in the first embodiment shown in FIG. 1, a space is formed between a transmitter 21 having two antennas and two receivers 22a and 22b having one antenna. -Although it is the structure which carries out frequency division multiple access, the case where the transmission antennas 6a and 6b of the transmitter 21 are arrange | positioned in the position far away is assumed. Therefore, the area A where the transmission signal of the transmission antenna 6a reaches and the area B where the transmission signal of the transmission antenna 6b arrives are greatly different. Regions A and B are examples for a certain subcarrier, and regions generated for each subcarrier differ in a propagation environment in which frequency selective fading occurs.

  Here, since signals do not reach regions A and B that do not belong to region B, it is not possible to perform communication using this subcarrier. However, other subcarriers may be included in one or both regions.

  Areas belonging to area A and area B can be subjected to space division multiple access by the operations shown in the first to third embodiments.

  Regions belonging only to region A are not affected by region B. In FIG. 5, the receiver 22a is located in this area. Therefore, the receiver 22a can perform communication regardless of the signal from the transmission antenna 6b. Similarly, a region belonging only to the region B is not affected by the region A. In FIG. 5, the receiver 22b is located in this area. Therefore, the receiver 22b can perform communication regardless of the signal from the transmission antenna 6a. The subcarrier allocation unit 10 operates to select such a combination. As a result, a plurality of independent transmission paths using the same subcarrier are formed, and the transmission speed of the entire system can be improved.

The figure which shows 1st Embodiment of the space and frequency division multiple access apparatus of this invention. The flowchart which shows the operation example of the subcarrier modulation and electric power distribution part 3a, 3b in 1st Embodiment. 9 is a flowchart showing an operation example of subcarrier modulation / power distribution units 3a and 3b in the second embodiment. The flowchart which shows the operation example of the subcarrier allocation part 10 in 3rd Embodiment. The figure which shows 4th Embodiment of the space and frequency division multiple access apparatus of this invention. The figure which shows the example of the conventional space division multiple access. The figure which shows the structural example of the conventional space division multiple access apparatus. The figure which shows the example of frequency selective fading.

Explanation of symbols

1a, 1b Transmission data section 2a, 2b Distribution section 3a, 3b Subcarrier modulation section 4a, 4b Weight multiplication section 5a, 5b IFFT calculation section 6a, 6b Transmission antenna 7a, 7b Reception antenna 8a, 8b Reception section 9a, 9b Subcarrier Modulation / power allocation unit 10 Subcarrier allocation unit 11 Weight calculation unit 12 Propagation parameter estimation unit 21 Transmitter 22a, 22b Receiver

Claims (10)

Spatial / frequency division multiple access apparatus for dividing and connecting space and frequency between one transmitter having a plurality of transmission antennas and one or more receivers each having one or more reception antennas and reception units In
The transmitter is
A transmission data part that holds transmission data to be transmitted to each receiving part of the receiver for each system, and
A distribution unit that inputs the transmission data of each system from the transmission data unit and distributes the data to one or more subcarriers occupied by the transmission data for each system;
A subcarrier modulation / power allocation unit that inputs transmission data distributed to each subcarrier from the distribution unit and determines the number of transmission bits and transmission power transmitted by each subcarrier under conditions that satisfy required communication quality; ,
Among the outputs of the subcarrier modulation / power allocation unit, the same number of weight multiplication units as the number of subcarriers for multiplying one or more transmission data using the same subcarrier,
An IFFT operation unit that performs inverse Fourier transform (IFFT transform) on signals of all subcarriers transmitted from one transmission antenna among outputs of the weight multiplication unit, and is connected to each of the transmission antennas;
A propagation parameter estimation unit for estimating a propagation parameter for each subcarrier between each transmission antenna and each reception antenna;
Each transmission data is referred to according to the number of transmission data lines to be transmitted to the reception unit, the requested bit rate, the transmission power of the transmission antenna, and the changing propagation parameter with reference to the allocation result of the subcarrier modulation / power allocation unit A subcarrier allocation unit that determines a subcarrier to be used and notifies the distribution unit;
In accordance with subcarrier allocation of the subcarrier allocation unit, the weight of each subcarrier transmitted from each transmission antenna for space division multiplexing is determined from the output of the propagation parameter estimation unit, and the subcarrier modulation / power allocation unit and A weight calculator for notifying the weight multiplier ,
The subcarrier allocation unit
Refers to the number of allocatable bits from the subcarrier modulation / power allocation unit, sets the same subcarrier combination occupied by the transmission data of each system as an unknown variable, and transmits the transmission data of all systems when a value is input to the unknown variable By assigning subcarriers so that the transmission data of each system occupies the same subcarrier by obtaining a solution of an unknown variable using a genetic algorithm as an objective function for maximizing the total bit rate of Spatial / frequency division multiple access device. Spatial / frequency division multiple access apparatus for dividing and connecting space and frequency between one transmitter having a plurality of transmission antennas and one or more receivers each having one or more reception antennas and reception units In
The transmitter is
A transmission data part that holds transmission data to be transmitted to each receiving part of the receiver for each system, and
A distribution unit that inputs the transmission data of each system from the transmission data unit and distributes the data to one or more subcarriers occupied by the transmission data for each system;
A subcarrier modulation / power allocation unit that inputs transmission data distributed to each subcarrier from the distribution unit and determines the number of transmission bits and transmission power transmitted by each subcarrier under conditions that satisfy required communication quality; ,
Among the outputs of the subcarrier modulation / power allocation unit, the same number of weight multiplication units as the number of subcarriers for multiplying one or more transmission data using the same subcarrier,
An IFFT operation unit that performs inverse Fourier transform (IFFT transform) on signals of all subcarriers transmitted from one transmission antenna among outputs of the weight multiplication unit, and is connected to each of the transmission antennas;
A propagation parameter estimation unit for estimating a propagation parameter for each subcarrier between each transmission antenna and each reception antenna;
Each transmission data is referred to according to the number of transmission data lines to be transmitted to the reception unit, the requested bit rate, the transmission power of the transmission antenna, and the changing propagation parameter with reference to the allocation result of the subcarrier modulation / power allocation unit A subcarrier allocation unit that determines a subcarrier to be used and notifies the distribution unit;
In accordance with subcarrier allocation of the subcarrier allocation unit, the weight of each subcarrier transmitted from each transmission antenna for space division multiplexing is determined from the output of the propagation parameter estimation unit, and the subcarrier modulation / power allocation unit and A weight calculator for notifying the weight multiplier ,
The subcarrier allocation unit
Refers to the number of allocatable bits from the subcarrier modulation / power allocation unit, sets the same subcarrier combination occupied by transmission data of each system as an unknown variable, and transmits the transmission data of each system when a value is input to the unknown variable As an objective function that satisfies the required bit rate, a solution of an unknown variable is obtained using a genetic algorithm, and subcarrier allocation is performed so that transmission data of each system occupies the same subcarrier. A featured space / frequency division multiple access device. Spatial / frequency division multiple access apparatus for dividing and connecting space and frequency between one transmitter having a plurality of transmission antennas and one or more receivers each having one or more reception antennas and reception units In
The transmitter is
A transmission data part that holds transmission data to be transmitted to each receiving part of the receiver for each system, and
A distribution unit that inputs the transmission data of each system from the transmission data unit and distributes the data to one or more subcarriers occupied by the transmission data for each system;
A subcarrier modulation / power allocation unit that inputs transmission data distributed to each subcarrier from the distribution unit and determines the number of transmission bits and transmission power transmitted by each subcarrier under conditions that satisfy required communication quality; ,
Among the outputs of the subcarrier modulation / power allocation unit, the same number of weight multiplication units as the number of subcarriers for multiplying one or more transmission data using the same subcarrier,
An IFFT operation unit that performs inverse Fourier transform (IFFT transform) on signals of all subcarriers transmitted from one transmission antenna among outputs of the weight multiplication unit, and is connected to each of the transmission antennas;
A propagation parameter estimation unit for estimating a propagation parameter for each subcarrier between each transmission antenna and each reception antenna;
Each transmission data is referred to according to the number of transmission data lines to be transmitted to the reception unit, the requested bit rate, the transmission power of the transmission antenna, and the changing propagation parameter with reference to the allocation result of the subcarrier modulation / power allocation unit A subcarrier allocation unit that determines a subcarrier to be used and notifies the distribution unit;
In accordance with subcarrier allocation of the subcarrier allocation unit, the weight of each subcarrier transmitted from each transmission antenna for space division multiplexing is determined from the output of the propagation parameter estimation unit, and the subcarrier modulation / power allocation unit and A weight calculator for notifying the weight multiplier ,
The subcarrier allocation unit
Refers to the number of allocatable bits from the subcarrier modulation / power allocation unit, sets the same subcarrier combination occupied by the transmission data of each system as an unknown variable, and transmits the transmission data of all systems when a value is input to the unknown variable By obtaining a solution of unknown variables using a genetic algorithm as an objective function that satisfies the required bit rate of transmission data of each system and maximizing the total bit rate of the transmission data of each system, A space / frequency division multiple access apparatus characterized in that subcarriers are allocated so as to occupy carriers . Spatial / frequency division multiple access apparatus for dividing and connecting space and frequency between one transmitter having a plurality of transmission antennas and one or more receivers each having one or more reception antennas and reception units In
The transmitter is
A transmission data part that holds transmission data to be transmitted to each receiving part of the receiver for each system, and
A distribution unit that inputs the transmission data of each system from the transmission data unit and distributes the data to one or more subcarriers occupied by the transmission data for each system;
A subcarrier modulation / power allocation unit that inputs transmission data distributed to each subcarrier from the distribution unit and determines the number of transmission bits and transmission power transmitted by each subcarrier under conditions that satisfy required communication quality; ,
Among the outputs of the subcarrier modulation / power allocation unit, the same number of weight multiplication units as the number of subcarriers for multiplying one or more transmission data using the same subcarrier,
An IFFT operation unit that performs inverse Fourier transform (IFFT transform) on signals of all subcarriers transmitted from one transmission antenna among outputs of the weight multiplication unit, and is connected to each of the transmission antennas;
A propagation parameter estimation unit for estimating a propagation parameter for each subcarrier between each transmission antenna and each reception antenna;
Each transmission data is referred to according to the number of transmission data lines to be transmitted to the reception unit, the requested bit rate, the transmission power of the transmission antenna, and the changing propagation parameter with reference to the allocation result of the subcarrier modulation / power allocation unit A subcarrier allocation unit that determines a subcarrier to be used and notifies the distribution unit;
In accordance with subcarrier allocation of the subcarrier allocation unit, the weight of each subcarrier transmitted from each transmission antenna for space division multiplexing is determined from the output of the propagation parameter estimation unit, and the subcarrier modulation / power allocation unit and A weight calculator for notifying the weight multiplier ,
The subcarrier allocation unit
The required transmission power is referred to from the subcarrier modulation / power allocation unit, the combination of the same subcarriers occupied by transmission data of each system is set as an unknown variable, and the transmission data of each system when a value is input to the unknown variable As an objective function for minimizing the required transmission power that satisfies the required bit rate, a subcarrier is used so that the transmission data of each system occupies the same subcarrier by obtaining a solution of an unknown variable using a genetic algorithm. A space / frequency division multiple access device characterized in that allocation is performed . In the space / frequency division multiple access apparatus according to any one of claims 1 to 4 ,
A space / frequency division multiple access apparatus, wherein one receiver includes a plurality of receiving antennas and a receiving unit, and the receiver receives transmission data of one or a plurality of systems. In the space / frequency division multiple access apparatus according to any one of claims 1 to 5 ,
The plurality of transmission antennas are installed at spatially separated positions, and each transmission antenna forms a different service area for each subcarrier,
The space / frequency division multiple access apparatus, wherein the subcarrier allocation unit is configured to select a combination of subcarriers in which transmission data of each system does not interfere. Spatial / frequency division multiple access method for dividing and connecting space and frequency between one transmitter having a plurality of transmitting antennas and one or more receivers each having one or more receiving antennas and a receiving unit In
The transmitter includes a transmission data unit, a distribution unit, a subcarrier modulation / power allocation unit, a weight multiplication unit, an IFFT calculation unit, a propagation parameter estimation unit, a subcarrier allocation unit, and a weight calculation unit,
Wherein the transmission data unit, the transmission data to be transmitted to the receiving unit of the receiver held by the system,
A dispensing step the distribution unit, which receives the transmission data of the respective systems from the transmission data unit, the transmission data for each of the systems is distributed to one or more subcarriers occupied,
The subcarrier modulation and power allocation unit receives the transmission data distributed to each subcarrier in the distribution step, under conditions that satisfy the required communication quality, transmission bits and transmit power each subcarrier transmits Subcarrier modulation and power allocation step for determining
A weight multiplication step of multiplying the weight to the weight multiplication unit is, in the output obtained by the subcarrier modulation and power allocation step, one or more transmission data using the same sub-carrier,
The IFFT calculation unit performs an inverse Fourier transform (IFFT transform) on all subcarrier signals transmitted from one transmission antenna among the outputs obtained in the weight multiplication step, and connects to each of the transmission antennas. A calculation step ;
The propagation parameter estimation unit, a propagation parameter estimation step of estimating the propagation parameters for each sub-carrier between the respective transmitting antennas each receiving antenna,
Propagating said subcarrier allocation unit refers to the allocation result in the sub-carrier modulation and power allocation step, line number of transmission data to be transmitted to the receiving unit, the request bit rate, transmission power of the transmitting antenna, and varies A subcarrier allocation step of determining a subcarrier to be used by each transmission data according to a parameter and notifying the distribution unit;
The weight calculation unit, in accordance with sub-carrier assignment in the subcarrier allocation step to determine the weight of each sub-carrier, wherein the transmitting from each transmitting antenna for space division multiplexing from the output obtained by the propagation parameter estimation step A weight calculation step for notifying the subcarrier modulation / power allocation unit and the weight multiplication unit ;
Run
In the subcarrier allocation step,
All systems when referring to the allocatable bit number obtained in the subcarrier modulation / power allocation step, the combination of the same subcarriers occupied by transmission data of each system is an unknown variable, and a value is input to the unknown variable As an objective function for maximizing the total bit rate of transmission data, a subcarrier allocation is performed so that the transmission data of each system occupies the same subcarrier by obtaining a solution of an unknown variable using a genetic algorithm. the space-frequency-division multiple access method and performing. Spatial / frequency division multiple access method for dividing and connecting space and frequency between one transmitter having a plurality of transmitting antennas and one or more receivers each having one or more receiving antennas and a receiving unit In
The transmitter includes a transmission data unit, a distribution unit, a subcarrier modulation / power allocation unit, a weight multiplication unit, an IFFT calculation unit, a propagation parameter estimation unit, a subcarrier allocation unit, and a weight calculation unit,
Wherein the transmission data unit, the transmission data to be transmitted to the receiving unit of the receiver held by the system,
A dispensing step the distribution unit, which receives the transmission data of the respective systems from the transmission data unit, the transmission data for each of the systems is distributed to one or more subcarriers occupied,
The subcarrier modulation and power allocation unit receives the transmission data distributed to each subcarrier in the distribution step, under conditions that satisfy the required communication quality, transmission bits and transmit power each subcarrier transmits Subcarrier modulation and power allocation step for determining
A weight multiplication step of multiplying the weight to the weight multiplication unit is, in the output obtained by the subcarrier modulation and power allocation step, one or more transmission data using the same sub-carrier,
The IFFT calculation unit performs an inverse Fourier transform (IFFT transform) on all subcarrier signals transmitted from one transmission antenna among the outputs obtained in the weight multiplication step, and connects to each of the transmission antennas. A calculation step ;
The propagation parameter estimation unit, a propagation parameter estimation step of estimating the propagation parameters for each sub-carrier between the respective transmitting antennas each receiving antenna,
Propagating said subcarrier allocation unit refers to the allocation result in the sub-carrier modulation and power allocation step, line number of transmission data to be transmitted to the receiving unit, the request bit rate, transmission power of the transmitting antenna, and varies A subcarrier allocation step of determining a subcarrier to be used by each transmission data according to a parameter and notifying the distribution unit;
The weight calculation unit, in accordance with sub-carrier assignment in the subcarrier allocation step to determine the weight of each sub-carrier, wherein the transmitting from each transmitting antenna for space division multiplexing from the output obtained by the propagation parameter estimation step A weight calculation step for notifying the subcarrier modulation / power allocation unit and the weight multiplication unit ;
Run
In the subcarrier allocation step,
Each system when referring to the allocatable bit number obtained in the subcarrier modulation / power allocation step, the combination of the same subcarrier occupied by the transmission data of each system is an unknown variable, and a value is input to the unknown variable As an objective function that satisfies the required bit rate of the transmission data, the subcarrier allocation is performed so that the transmission data of each system occupies the same subcarrier by obtaining a solution of the unknown variable using a genetic algorithm. the space-frequency-division multiple access method and performing. Spatial / frequency division multiple access method for dividing and connecting space and frequency between one transmitter having a plurality of transmitting antennas and one or more receivers each having one or more receiving antennas and a receiving unit In
The transmitter includes a transmission data unit, a distribution unit, a subcarrier modulation / power allocation unit, a weight multiplication unit, an IFFT calculation unit, a propagation parameter estimation unit, a subcarrier allocation unit, and a weight calculation unit,
Wherein the transmission data unit, the transmission data to be transmitted to the receiving unit of the receiver held by the system,
A dispensing step the distribution unit, which receives the transmission data of the respective systems from the transmission data unit, the transmission data for each of the systems is distributed to one or more subcarriers occupied,
The subcarrier modulation and power allocation unit receives the transmission data distributed to each subcarrier in the distribution step, under conditions that satisfy the required communication quality, transmission bits and transmit power each subcarrier transmits Subcarrier modulation and power allocation step for determining
A weight multiplication step of multiplying the weight to the weight multiplication unit is, in the output obtained by the subcarrier modulation and power allocation step, one or more transmission data using the same sub-carrier,
The IFFT calculation unit performs an inverse Fourier transform (IFFT transform) on all subcarrier signals transmitted from one transmission antenna among the outputs obtained in the weight multiplication step, and connects to each of the transmission antennas. A calculation step ;
The propagation parameter estimation unit, a propagation parameter estimation step of estimating the propagation parameters for each sub-carrier between the respective transmitting antennas each receiving antenna,
Propagating said subcarrier allocation unit refers to the allocation result in the sub-carrier modulation and power allocation step, line number of transmission data to be transmitted to the receiving unit, the request bit rate, transmission power of the transmitting antenna, and varies A subcarrier allocation step of determining a subcarrier to be used by each transmission data according to a parameter and notifying the distribution unit;
The weight calculation unit, in accordance with sub-carrier assignment in the subcarrier allocation step to determine the weight of each sub-carrier, wherein the transmitting from each transmitting antenna for space division multiplexing from the output obtained by the propagation parameter estimation step A weight calculation step for notifying the subcarrier modulation / power allocation unit and the weight multiplication unit ;
Run
In the subcarrier allocation step,
All systems when referring to the allocatable bit number obtained in the subcarrier modulation / power allocation step, the combination of the same subcarriers occupied by transmission data of each system is an unknown variable, and a value is input to the unknown variable By obtaining a solution of unknown variables using a genetic algorithm as an objective function that maximizes the total bit rate of the transmission data and satisfies the required bit rate of the transmission data of each system, the transmission data of each system is A space / frequency division multiple access method, wherein subcarriers are allocated so as to occupy the same subcarrier . Spatial / frequency division multiple access method for dividing and connecting space and frequency between one transmitter having a plurality of transmitting antennas and one or more receivers each having one or more receiving antennas and a receiving unit In
The transmitter includes a transmission data unit, a distribution unit, a subcarrier modulation / power allocation unit, a weight multiplication unit, an IFFT calculation unit, a propagation parameter estimation unit, a subcarrier allocation unit, and a weight calculation unit,
Wherein the transmission data unit, the transmission data to be transmitted to the receiving unit of the receiver held by the system,
A dispensing step the distribution unit, which receives the transmission data of the respective systems from the transmission data unit, the transmission data for each of the systems is distributed to one or more subcarriers occupied,
The subcarrier modulation and power allocation unit receives the transmission data distributed to each subcarrier in the distribution step, under conditions that satisfy the required communication quality, transmission bits and transmit power each subcarrier transmits Subcarrier modulation and power allocation step for determining
A weight multiplication step of multiplying the weight to the weight multiplication unit is, in the output obtained by the subcarrier modulation and power allocation step, one or more transmission data using the same sub-carrier,
The IFFT calculation unit performs an inverse Fourier transform (IFFT transform) on all subcarrier signals transmitted from one transmission antenna among the outputs obtained in the weight multiplication step, and connects to each of the transmission antennas. A calculation step ;
The propagation parameter estimation unit, a propagation parameter estimation step of estimating the propagation parameters for each sub-carrier between the respective transmitting antennas each receiving antenna,
Propagating said subcarrier allocation unit refers to the allocation result in the sub-carrier modulation and power allocation step, line number of transmission data to be transmitted to the receiving unit, the request bit rate, transmission power of the transmitting antenna, and varies A subcarrier allocation step of determining a subcarrier to be used by each transmission data according to a parameter and notifying the distribution unit;
The weight calculation unit, in accordance with sub-carrier assignment in the subcarrier allocation step to determine the weight of each sub-carrier, wherein the transmitting from each transmitting antenna for space division multiplexing from the output obtained by the propagation parameter estimation step A weight calculation step for notifying the subcarrier modulation / power allocation unit and the weight multiplication unit ;
Run
In the subcarrier allocation step,
Referring to the required transmission power obtained in the subcarrier modulation / power allocation step, the combination of the same subcarriers occupied by transmission data of each system is set as an unknown variable, and the value of each system when a value is input to the unknown variable As an objective function for minimizing the required transmission power that satisfies the required bit rate of transmission data, a solution of unknown variables is obtained using a genetic algorithm so that the transmission data of each system occupies the same subcarrier. A spatial / frequency division multiple access method, characterized in that subcarriers are allocated to each other .

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