JP3869402B2 - MIMO radio signal transmission device - Google Patents

Description

  The present invention relates to a radio communication system, and more particularly, to a MIMO radio signal transmission apparatus that configures a MIMO (Multiple-Input Multiple-Output) channel using a plurality of transmission antennas and a plurality of reception antennas.

  In a wireless communication system, the received power on the receiving station side is affected by the distance between the transmitting station and the receiving station, surrounding reflectors, and the like. Therefore, in the radio communication system, the reception power on the receiving station side depends significantly on the positions of the transmitting station and the receiving station. For example, in a mobile radio communication system composed of a base station whose position is fixed and a mobile station whose position is movable, the received power on the receiving station side depends on the position of the mobile station.

  In SISO (Single-Input Single-Output) transmission in which a radio signal is transmitted using one transmitting antenna and one receiving antenna, the signal quality of the received signal is a ratio SNR (Signal of the received power and noise power of one receiving system). -Depends on Noise-Ratio). However, since the average value of the thermal noise power is constant regardless of the position of the mobile station, it can be considered that the signal quality of the received signal substantially depends on the received power.

  In such SISO transmission, when the transmission power on the transmission station side is constant, the reception power on the reception station side varies every time the mobile station moves, so it is difficult to keep the received signal quality constant, It is difficult to provide a stable wireless communication service.

  In order to prevent this, grasp the receiving power of the partner station from the receiving power of its own station or control signal so that the receiving power of the partner station side is kept constant, and transmit power of its own station according to the receiving power of this partner station Is often applied (referred to as “transmission power control with constant reception power”) (see Non-Patent Document 1).

  When this transmission power constant transmission power control is applied to the transmission station side, reception is performed at a constant reception power with the base station side and the mobile station side regardless of the position of the mobile station within the range of transmission power values that can be transmitted on the transmission station side. Therefore, it is possible to provide a stable communication service. A conceptual diagram specifically showing this is shown in FIG.

In FIG. 5, the base station is the transmitting station and the mobile station is the receiving station. When the transmission power of the base station is constant (graph 5-1 in FIG. 5), the reception power of the mobile station varies depending on the position of the mobile station (graph 5-2 in FIG. 5). The received power of the mobile station can be kept at the required received power value by increasing the transmission power of the base station by a small amount with respect to the required received power for a certain signal quality (graph 5-3 in FIG. 5). This is possible (graph 5-4 in FIG. 5). Thereby, it is possible to maintain a certain radio signal quality for the mobile station, and it is possible to provide a stable radio communication service.
“Proposal of specification of uplink power control in HYPERLAN / 2”, ETSI EP BRAN # 13.5 HL13.5ERI8A

  However, the above-described constant reception power transmission power control is configured from a plurality of transmission antennas and a plurality of reception antennas to form a MIMO (Multiple-Input Multiple-Output) channel, and is estimated from the reception signal of each reception antenna on the reception side. When applied to MIMO transmission in which all transmission signals from each transmission antenna are restored by performing MIMO channel demodulation such as canceling ICI (Inter-Channel-Interference) using the transmission response of each MIMO channel, the following problems occur: Occurs.

The number of transmission antennas is N (2 ≦ N), and radio signals transmitted from the respective transmission antennas are represented by vectors T (T = (t ₁ , t ₂ ,..., T _N ) ^t , ^t are transposed vectors, T _i I is a transmission antenna number). The number of receiving antennas is M, and the radio signal received by each receiving antenna is R (R = (r ₁ , r ₂ ,..., R _M ) ^t , ^t is a transposed vector, and _j of r j is a receiving antenna number. )far. The transfer response of the transmit antennas j-th and receive antenna i h _ij Distant, placing and H transmission response matrix of h _ij and each element, T, R, H, the following relationship exists between.

Here, each element n _i of the vector N (N = (n ₁ , n ₂ ,..., N _M )) represents a thermal noise signal component generated from the reception branch connected to each reception antenna i. Show.
MIMO channel demodulation processing for restoring the transmission signal t _j from the received signal R based on the estimated transfer response matrix H is performed using W _j (r ₁ , r ₂ ,..., R _M ; H) (t _j = W _j ( r ₁ , r ₂ ,..., r _M ; H)), the restored signal T ^˜ (T ^˜ = (t ₁ ^˜ , t ₂ ^˜ ..., t _N ^˜ ) after this demodulation processing. ^{t 1} , ^t are transposed vectors, and t _j ^˜ are restoration signals for the radio signal t _j ) are expressed as follows:

Therefore, the recovered signal _t ^j SNR _j for ^~ is expressed as follows.

Therefore, the average of samples (time) of SNR _j , | t _j |, | W _j (n ₁ , n ₂ ,... N _M ; H) | is (SNR _j ) _AVR , | t _j | _AVR , | ( W _j (n ₁ , n ₂ ,... N _M ; H)) | _AVR , (SNR _j ) _AVR is

It becomes. Now, the average for each recovered signal t j ~ (SNR j) AVR is demodulation W j (r 1, r 2 , ···, r M; H) thermal noise signal components generated function form a receiving branch N (N = (n 1 , n 2 ,..., N M )).

FIG. 6 is a diagram showing the received power (SNR _j ) _AVR when the constant received power transmission power control is applied to this system. The reception power | Li | ² of each reception antenna i is expressed as follows.

When the received power constant transmission power control is applied, the value of the transmission power | t _j | _AVR is controlled so that the received power | Li | ² becomes a constant value | L | ² (6-1 and 6 in FIG. 6). -2). That is,

Is used to determine the degree of amplification α _j for the radio signal t _j . At this time, (SNR _j ) _AVR is obtained from _Equations 4 and 6.

It becomes.

Therefore, (SNR _j ) _AVR is | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR , | W _j (r ₁ , r ₂ ,..., R _M ; H) | depends on ² _AVR, amplification factor alpha _j is _{| W j (n 1, n} 2, ··· n M; H) | because it is determined according to the number 6 unrelated and _{2 AVR,} amplification factor alpha _j (SNR _j ) _AVR cannot be made constant.
Therefore, when the value of | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR changes according to the position of the mobile station (6-3 in FIG. 6), the received power constant transmission power control The (SNR _j ) _AVR in Equation 7 cannot be made constant (6-4 in FIG. 6). That is, when MIMO transmission is used in an environment where | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR changes depending on the position of the mobile station, the received power constant transmission power control is applied. However, there is a problem that it is difficult to provide a stable wireless communication service.

The present invention has been made in view of such _{circumstances, | W j (n 1,} n 2, ··· n M; H) | by controlling the transmission power based on _{2 AVR} value, in MIMO transmission (SNR _j ) An object of the present invention is to provide a MIMO radio signal transmission apparatus in which _AVR is constant.

  According to the present invention, the above problem is solved by the following means.

The first invention includes N (N ≧ 2) transmission antennas, and the radio signals T (T = (t ₁ , t ₂ ,...) Using the same frequency from the N transmission antennas. t _N ) ^t , t is a transposed vector, _i of t _i is a transmission antenna number), M (M ≧ 1) reception antennas, and the N transmission antennas and The transfer response matrix H of N × M radio paths, which is a combination with M receive antennas, can be estimated (the (i, j) component h _ij of H is the transfer response between the transmit antenna j and the receive antenna i). And M received signals R (R = (r ₁ , r ₂ ,..., R _M ) ^t , t is a transposed vector, _j of r j is a receiving antenna number), and the estimated transfer response matrix H determined based on the demodulation process _{W j (r 1, r 2} , ···, r M; H) (1 ≦ j ≦ N Original wireless signal _{t j (t j = W j} (r 1, r 2, ... r M; H)) by the applied MIMO radio signal transmission apparatus N × M; and a radio signal receiving apparatus for restoring In
The radio signal receiving device includes means for constantly notifying the radio signal transmitting device of the estimated transfer response matrix H, and the radio signal transmitting device includes an arbitrary transfer response matrix H in the radio signal receiving device. means for the thermal noise power of the receiver branches that the connected to the receiving antennas in the radio signal receiving apparatus _known; the respect _all demodulation processing _{Wj (H all r 1, r} 2, ··· r M) In the radio signal receiving apparatus, the notified transfer response matrix H, the known demodulation processing W _j (r ₁ , r ₂ ,... R _M ; H) and the known thermal noise power are used. The noise power a _j after the demodulation processing W _j (r ₁ , r ₂ ,..., R _M ; H) is calculated, and the j-th transmission power of the transmission antenna is proportional to the calculated noise power a _j. Means to control Comprises a, it is MIMO radio signal transmission apparatus according to claim.

The second invention includes N (N ≧ 2) transmission antennas, and uses the same frequency from the N transmission antennas to transmit a radio signal T (T = (t ₁ , t ₂ ,..., t _N ) ^t , t is a transposed vector, _i of t _i is a transmission antenna number), M (M ≧ 1) reception antennas, and the N transmission antennas and The transfer response matrix H of N × M radio paths, which is a combination with M receive antennas, can be estimated (the (i, j) component h _ij of H is the transfer response between the transmit antenna j and the receive antenna i). And M received signals R (R = (r ₁ , r ₂ ,..., R _M ) ^t , t is a transposed vector, _j of r j is a receiving antenna number), and the estimated transfer response matrix H determined based on the demodulation process _{W j (r 1, r 2} , ···, r M; H) (1 ≦ j ≦ N Original wireless signal _{t j (t j = W j} (r 1, r 2, ... r M; H)) by the applied MIMO radio signal transmission apparatus N × M; and a radio signal receiving apparatus for restoring In
The radio signal receiving apparatus includes the demodulation processing W _j (r ₁ , r ₂ ,... R _M ; H _all ) for the estimated arbitrary transfer response matrix H _all and the receiving branch connected to each receiving antenna. Means for making known thermal noise power, the estimated transfer response matrix H, the known demodulation process W _j (r ₁ , r ₂ ,... R _M , H _all ) and the known thermal noise. the demodulation process _W j in the wireless signal receiving apparatus using a power _{(r 1, r 2, ···} , r M; H) calculates a noise power _{a j} after the noise power _{a j} with the calculated Means for steadily notifying the radio signal transmitter, and the radio signal transmitter controls the j-th transmit power of the transmit antenna in proportion to the notified noise power a _j. MI characterized by comprising O is a wireless signal transmission device.

The third invention includes N (N ≧ 2) transmission antennas, and uses the same frequency from the N transmission antennas to transmit a radio signal T (T = (t ₁ , t ₂ ,..., t _N ) ^t , t is a transposed vector, _i of t _i is a transmission antenna number) by a TDD system, and M (M ≧ 1) reception antennas, and the N transmissions Transfer response matrix H of N × M radio paths that is a combination of an antenna and the M reception antennas (H (i, j) component h _ij is a transfer response between transmission antenna j and reception antenna i) Can be estimated, and the above estimated transmission is performed on M received signals R (R = (r ₁ , r ₂ ,..., R _M ) ^t , t is a transposed vector, and _j of r j is a receiving antenna number). determined based on the response matrix H demodulation _{W j (r 1, r 2} , ···, r M; H) 1 ≦ j ≦ N) original radio signal by a applying _{t j (t j = W j} (r 1, r 2, ... r M; H)) N × M ; and a radio signal receiving apparatus for restoring In the MIMO radio signal transmission apparatus, the radio signal reception apparatus includes means for constantly transmitting a pilot signal, and the radio signal transmission apparatus estimates the transfer response matrix H by receiving the pilot signal. And the demodulation processing W _j (r ₁ , r ₂ ,... R _M ; H _all ) of the radio signal receiving apparatus for an arbitrary transfer response matrix H _all and each receiving antenna in the radio signal receiving apparatus. Means for making known the thermal noise power of the receiving branch, the estimated transfer response matrix H, the known demodulation processing W _j (r ₁ , r ₂ ,... R _M ; H _all ) and the known Was The demodulation process _W j in the wireless signal receiving apparatus using the noise power _{(r 1, r 2, ···} , r M; H) calculates a noise power _{a j} after noise power _{a j} with the calculated And a means for controlling the j-th transmission power of the transmission antenna in proportion to the transmission power of the MIMO radio signal transmission apparatus.

As described above, according to the MIMO radio signal transmission apparatus according to the present invention, the transmission power is controlled based on the value of | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR. Thus, (SNR _j ) _AVR can be _kept constant in MIMO transmission.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a diagram showing a first embodiment of the present invention. Example 1 is an example of the MIMO radio signal transmission apparatus according to the first invention.

As illustrated in FIG. 1, the MIMO radio signal transmission apparatus according to the first embodiment includes a radio signal transmission apparatus 1 and a radio signal reception apparatus 2.
In the wireless signal transmission device 1, first, N independent wireless signals T = (t ₁ , t ₂ ,..., T _N ) ^t are input. The radio signal T may be supplied with N data signal sequences independent from the outside such as a PC, and each of them may be independently radio-modulated. Similarly, one radio signal T from the outside such as a PC may be used. The data signal sequence is supplied, and after the radio apparatus decomposes the data signal sequence into N data signal sequences by serial-parallel conversion, each of the data signal sequences may be wirelessly modulated independently. The wireless device itself may generate N independent data signals and wirelessly modulate them.

The radio signal transmission device 1 responds to this radio signal T.
A path transfer response matrix H estimation pilot signal generating unit 1-1 for generating a path transfer response matrix H estimation pilot signal for the radio signal receiving apparatus 2 to estimate the transfer response matrix H;
N signal multiplexing means 1-2-1 to 1-2-N for adding a path transfer response matrix H estimation pilot signal to the radio signal T;
N frequency conversion means 1-3-1 to 1-3-N for converting the output signals of N signal multiplexing means 1-2-1 to 1-2N to radio frequencies,
A variable amplifier 1-4-1 to 1-4 -N having a variable amplification degree for amplifying the output signals of the N frequency conversion means;
N transmission antennas 1-5-1 to 1-5-N for wirelessly transmitting N signals amplified by N variable amplifiers 1-4-1 to 1-4-N,
A receiving antenna 1-6 for acquiring information of a path transfer response matrix H estimated by the radio signal receiving apparatus 2 described later;
Demodulation means 1-7 for demodulating the signal received by the receiving antenna;
A demodulating process W _j (r ₁ , r ₂ ,... R _M ; H _all ) for an arbitrary transfer response matrix H _all in the radio signal receiving apparatus 2 described later, and each receiving antenna in the radio signal receiving apparatus A radio signal using the transfer response matrix H demodulated by the demodulating means, the demodulating process W _j (r ₁ , r ₂ ,... R _M ; H _all ), and the thermal noise power. The noise power a _j after demodulation processing W _j (r ₁ , r ₂ ,..., R _M ; H) in the receiving apparatus is calculated, and the variable amplifier 1-4 is proportional to the calculated noise power a _j. It comprises transmission power control means 1-8 for controlling the amplification factor of -j.

Further, the radio signal receiving device 2 is
-M receiving antennas 2-1-1-2-1 -M
Frequency conversion means 2-2-1 to 2-2N for frequency-converting the signals received by the receiving antennas 2-1-1 to 2-1-M to the baseband;
A transmission response matrix H estimation means 2-3 for estimating a path transmission response matrix H from a pilot signal for path transmission response matrix H estimation received by the M receiving antennas;
Based on the transfer response matrix H estimated by the transfer response matrix H estimation means 2-3, M received signals R = (r ₁ ) received by the M receiving antennas 2-1-1-2-1 -M. , R ₂ ,..., R _N ) ^t , demodulation processing W _j (r ₁ , r ₂ ,..., R _M ; H) (t _j for restoring the original N radio signals T MIMO channel demodulating means 2-4 for performing = W _j (r ₁ , r ₂ ,..., R _M ; H), (1 ≦ j ≦ N))
A modulation means 2-5 for modulating information of the estimated transfer response matrix H into a radio signal in order to notify the radio signal transmitting apparatus 1 of the transfer response matrix H estimated by the transfer response matrix H estimating means 2-3;
A transmitting antenna 2-6 for wirelessly transmitting a wireless signal modulated by the modulating means;
Consists of

First, in the wireless signal transmission device 1, the wireless signal reception device 2 estimates the path transfer response matrix H prior to _N wireless signals T = (t ₁ , t ₂ ,..., T _N ) ^t to be transmitted. For generating the transmission response matrix H estimation pilot signal having a known signal pattern by the transmission response matrix H estimation pilot signal generating means 1-1, and N signal multiplexing means 1- The transmission response matrix H estimation pilot signal is added before _N radio signals T = (t ₁ , t ₂ ,..., T _N ) ^t by 2-1 to 1-2-N.

  The transmission response matrix H estimation pilot signal may be any pilot signal pattern as long as the wireless signal receiving apparatus 2 can estimate the transmission response matrix H. For example, a mode in which the same pilot signal pattern is transmitted from each transmission antenna in a time division manner is conceivable. This signal pattern is shown in FIG.

In FIG. 3, for example, the same pilot signal pattern is transmitted in order from the transmission antenna 1, and other transmission antennas are not transmitting while transmitting a pilot signal from a certain transmission antenna. In this case, for example, when a pilot signal is transmitted from the transmission antenna j, the reception antenna i of the wireless signal receiving apparatus 2 receives only the pilot signal from the transmission antenna j via the reception antenna i. If the device 2 knows the pilot signal pattern, the transfer response h _ij between the transmitting antenna j and the receiving antenna i can be estimated.

Hereinafter, if a similar operation is performed for each pilot antenna sequentially transmitted from each transmission antenna, the transmission responses h _ij of all combinations of N transmission antennas and M reception antennas, that is, transmission responses, are performed. The matrix H can be estimated. If the radio signal receiver is equipped with automatic gain control (AGC), after automatic gain control (AGC), each received power | L _i | ² is adjusted to maintain a constant level regardless of _hij. Is done. This transmission response h _ij is a pure transmission response in space from the transmission antenna j to the reception antenna i that does not include power amplification by this automatic gain control (AGC). As a method for estimating such a transfer response h _ij , a method is conceivable in which h _ij estimated by the above method is further divided by the power gain of automatic gain control (AGC).

The operation for estimating the transfer response matrix H in the radio signal receiving apparatus 2 is performed by the transfer response matrix H means 2-2 in FIG.
N multiplexing means 1-2-1 to 1-2-N add a pilot signal for estimating a transfer response matrix H to _N radio signals T = (t ₁ , t ₂ ,..., T _N ) ^t. The N signals thus converted are converted into a radio frequency band by N frequency converting means 1-3-1 to 1-3-N.

Since the MIMO wireless signal transmission apparatus according to the first embodiment uses the demodulation processing W _j (r ₁ , r ₂ ,..., R _M ; H) in the wireless signal receiving apparatus 2 on the wireless signal transmitting apparatus 1 side, it is wireless. It is necessary to acquire the transfer response matrix H in the direction of the wireless signal receiving device 2 from the signal transmitting device 1.

  In the MIMO radio signal transmission apparatus according to the first embodiment, assuming that the radio response transmitter H cannot estimate the transfer response matrix H, such as FDD transmission, the transfer response matrix H estimated by the radio signal receiver 2 is assumed. To the wireless signal transmitting apparatus 1. For this purpose, the wireless signal receiving device 2 wirelessly transmits the information of the transmission response matrix H estimated by the transmission response matrix H estimation unit 2-2 to the wireless signal transmission device 1 by the modulation unit 2-4 and the transmission antenna 2-5. To do. The wireless signal transmission device 1 acquires the information of the transfer response matrix H by the reception antenna 1-6 and the demodulation unit 1-7. Thereafter, the acquired transmission response matrix H is transmitted to the transmission power control means 1-7.

The transmission power control means 1-8 is connected in advance to a demodulation process W _j (r ₁ , r ₂ ,... R _M ; H _all ) for an arbitrary transfer response matrix H _{all and} each receiving antenna in the radio signal receiving apparatus. It is assumed that the thermal noise power (n ₁ ² ) _AVR , (n ₂ ² ) _AVR ,... (N _M ² ) _AVR of the received branch is known.

Note that the method in which the transmission power control means 1-8 makes the demodulation processing W _j (r ₁ , r ₂ ,... R _M ; H _all ) known in advance is sent to the transmission power control means 1-8 in advance by the demodulation processing W _j. A method of registering a function form for the transfer response matrix H of (r ₁ , r ₂ ,..., R _M ; H _all ) is conceivable.

The transmission power control means 1-8 makes the average power (n ₁ ² ) _AVR , (n ₂ ² ) _AVR ,... (N _M ² ) _AVR of the noise signal known as (NF _i × There is a method in which the value of required band B × temperature T × Boltzmann constant k) is registered in advance in transmission power control means 1-8. Here, NF _i is a noise figure (NF) of the reception branch _i included in the wireless signal reception device 2.

If the circuit configuration of each reception branch is the same, NF _i (= NF) of each reception branch of the radio signal reception device is made equal, and the average power (n ₁ ² ) _AVR of the noise signal of each reception branch , (N ₂ ² ) _AVR ,... (N _M ² ) There is also a method of registering _AVR as (NF × required bandwidth B × temperature T × Boltzmann constant k).
Further, there is a method in which the NF of the own radio signal transmitter 1 is registered in advance in the transmission power control means 1-8, assuming that the NF of the radio signal transmitter is equal to the NF of the radio signal receiver.

The transmission power control means 1-8 determines the demodulation processing W _j (r ₁ , r ₂ ,..., R _M ; H) of the radio signal receiving device 2 based on the notified transfer response matrix H. Then, independently of one another a is dispersed thermal noise power ^{_{(n 1 2) AVR, (}} n 2 2) AVR, ··· (n N 2) respectively equal to Gaussian noise variables _n 1 in _AVR, n 2, · · ·, n _N is substituted into demodulation processing W _j (r ₁ , r ₂ ,..., r _M ; H), and the sample average value | W _j (n ₁ , n ₂ ,. n _M ; H) | ² _AVR is calculated.

The sample average value | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR is, as can be seen from Equation 7, the demodulation processing W _j (r ₁ , r ₂ ,. .., R _M ; H) Reflects the noise power for the radio signal t _j after. The transmission power control means 1-8 is a variable amplifier 1-4 for the radio signal T _j in proportion to the calculated sample average value | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR. The amplification degree β _j of _j is determined. That is,

Here, k ² is a proportionality constant, an amount which does not depend on the transmission antenna number j.

The N output signals from the N frequency converting units 3-1-3 to 1-3 -N are amplified by the variable amplifier 1-4-1 to 1-4 -N and the amplification factor β ₁ according to the equation (8). after being amplified by ~β _N, it is transmitted from the transmitting antennas 1-5-1-1-5-N.

As described above, the radio signal transmitted from the transmitting antenna 1-5-1-1-5-N in the case of controlling the amplification degree β ₁ ~β _N of the variable amplifier 1-4-1~1-4-N Where T ^t = (t ₁ ^t , t ₂ ^t ,... T _N ^t ) ^t

It becomes.

At this time, the received signal R = (r ₁ , r ₂ ,..., R _N ) ^t received by the wireless signal receiving device 2 is expressed as follows.

The radio signal receiving apparatus 2 uses the MIMO channel demodulation unit 2-3 to perform demodulation processing W _j (r ₁ , r) determined based on the transfer response matrix H estimated by the transfer response matrix H unit 2-2 for the received signal R. ₂ ,..., R _M ; H) to restore the original radio signal T ^t . If the restoration signal is T ^{t ˜} = (t ₁ ^t˜ , t ₂ ^t˜ ,..., T _N ^t˜ ) ^t ,

It becomes. From Equation 9, Equation 10, and Equation 11,
Each recovered signal _t ^j average values of SNR for ^~ _{(SNR j) AVR} is

It becomes.

Therefore, the transmission power control for controlling the amplification degree β ₁ ~β _N of more variable amplifier 1-4-1~1-4-N, transmission antenna number j, regardless of the transmission response matrix H, recovered signal ^{T t} = (T ₁ ^t , t ₂ ^t ,... T _N ^t ) The average SNR of each component of ^t can be a constant value k ² | t _j | ² _AVR . Therefore, for example, if the required SNR for the required radio signal quality and this k ² | t _j | ² _AVR or higher are set, the average value (SNR _j ) _AVR can be kept higher than the required SNR regardless of the transfer response matrix H. It is. FIG. 4 shows the above concept and a qualitative graph.

In FIG. 4, as in FIGS. 5 and 6, the radio signal transmitting apparatus 1 is a base station, and the radio signal receiving apparatus 2 is a mobile station. When the transmission power of the base station is constant (graph 4-1 in FIG. 4), | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR of the mobile station depends on the position of the mobile station. It fluctuates (graph 4-2 in FIG. 4).

At this time, since the average SNR _j after the inter-channel interference canceller of the mobile station is expressed by Equation 4, the average SNR varies depending on the position of the mobile station (graph 4-3 in FIG. 4). However, when the transmission power control of the present invention is used, the transmission power of the base station is expressed by Equation 8 based on | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR of the mobile station. In order to control, the average SNR _j after the demodulation processing of the mobile station can be kept constant regardless of the position in the mobile station as shown in Equation 12.

  Therefore, according to the MIMO radio signal transmission apparatus according to the first embodiment, it is possible to stably provide a radio communication service in MIMO transmission.

Note that the specific value of | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR is, for example, equal to the number of transmitting antennas N and the number of receiving antennas M, and demodulation processing W _j (r ₁ , R ₂ ,..., R _M ; H) is the multiplication of the inverse matrix H ⁻¹ of the transfer response matrix H with respect to the received signal R, that is, the (i, j) component of the inverse matrix H ⁻¹ is represented as h ^′ _ij . If you leave

Then, from Expressions 11 and 13, | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR is as follows.

Assuming that the average powers of the thermal noise signals n ₁ , n ₂ ,..., _{N N} of the reception branches of the radio signal receiver 2 are equal (= σ ² ),

Therefore, when the demodulation processing W _j (r ₁ , r ₂ ,..., R _M ; H) is an inverse matrix H ⁻¹ multiplication of the transfer response matrix H, the radio signal transmission device 1 transmits the transfer response matrix H and the radio signal. if grasping average thermal noise power sigma ² of each receiving branch of the receiver 2, easily _{| W j (n 1, n} 2, ··· n M; H) | 2 AVR can be calculated.

  The MIMO radio signal transmission apparatus according to the first embodiment is also applicable to a MIMO-OFDM scheme that applies an OFDM (Othological Frequency Division Multiplexing) signal transmission scheme of a multicarrier system to MIMO transmission.

  In the OFDM signal transmission method, each subcarrier can be demodulated independently if the delay time of the multipath wave is within the guard interval. That is, it is possible to handle the transmission of each subcarrier independently. In such a case, the same equations 8 to 12 are established in each subcarrier.

  Therefore, if the MIMO radio signal transmission apparatus according to the first embodiment is applied to the MIMO-OFDM scheme, the average SNR of subcarrier components for all transmission antennas can be made constant for a certain subcarrier component.

Further, if the constant of proportionality k ² that determines the amplification factor of the variable amplifier with respect to the value of | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _{AVR in Equation 12} is constant in all subcarriers, It is possible to make the average SNR constant for all subcarrier components for all transmit antennas, ie, all modulation symbols.

  Therefore, by applying the MIMO radio signal transmission apparatus according to the first embodiment to the MIMO-OFDM scheme, it becomes possible to provide a wireless communication service stably.

  Example 2 is an example of the MIMO radio signal transmission apparatus according to the second invention.

The MIMO radio signal transmission apparatus according to the second embodiment is the | W _j (n ₁ , n ₂ ,..., N _M ; H performed by the radio signal transmission apparatus 1 in the MIMO radio signal transmission apparatus according to the first embodiment. ) | ² _AVR is calculated by the wireless signal receiver 2, and the calculated | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR is notified to the wireless signal transmitter 1. a radio signal transmitting device 1 notifies to ask the _{| W j (n 1, n} 2, ··· n M; H) | is characterized by performing the _second transmission power control based on the _AVR.

The block configuration of the radio signal transmitting apparatus and the radio signal receiving apparatus included in the MIMO radio signal transmission apparatus according to the second embodiment is the block configuration of the radio signal transmitting apparatus and the radio signal receiving apparatus included in the MIMO radio signal transmission apparatus according to the first embodiment. Is exactly the same. | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR is calculated by the transfer response matrix H estimator 2-3 in the radio signal receiver 2.

The transfer response matrix H estimation means 2-3 preliminarily performs demodulation processing W _j (r ₁ , r ₂ ,... R _M ; H _all ) on an arbitrary transfer response matrix H _{all and} each reception antenna in the radio signal receiving apparatus. It is assumed that the thermal noise power (n ₁ ² ) _AVR , (n ₂ ² ) _AVR ,... (N _M ² ) _AVR of the receiving branch connected to is known.

Note that the method in which the transfer response matrix H estimation means 2-3 knows the demodulation processing W _j (r ₁ , r ₂ ,... R _M ; H _all ) is demodulated in advance by the transfer response matrix H estimation means 2-3. A method of registering a function form for the transfer response matrix H of the processing W _j (r ₁ , r ₂ ,... R _M ; H _all ) is conceivable.

In addition, the method in which the transfer response matrix H estimation unit 2-3 makes the average power (n ₁ ² ) _AVR , (n ₂ ² ) _AVR ,... ( _{N N} ² ) _AVR of the noise signal known is described in the first embodiment. It is the same as the case of.

The transfer response matrix H estimation means 2-3 estimates the transfer response matrix H as in the case of the first embodiment. Then, the estimated transfer response matrix H, demodulation processing W _j (r ₁ , r ₂ ,... R _M ; H _all ), average power (n ₁ ² ) _AVR , (n ₂ ² ) _AVR,. .. (n _N ² ) Using _AVR , the transmission power control means 1-7 of the wireless signal transmission apparatus 1 of the first embodiment is | W _j (n ₁ , n ₂ ,... N _M ; H) | ² by exactly the same manner as calculating the _{AVR, | W j (n 1} , n 2, ··· n M; H) | calculates the _{2 AVR.} Thereafter, the information of | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR is notified to the wireless signal transmission device 1 by the modulation means 2-5 and the transmission antenna.

The wireless signal transmission device 1 acquires the notified | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR information by the reception antenna 1-6 and the demodulation unit 1-7. The demodulating means 1-7 transmits the acquired | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR information, and the transmission power control means 1-8 transmits the information.

The transmission power control means 1-8 uses the variable amplifier based on the obtained | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR , just as in the first embodiment. 1-4-1~1-4-N to set an amplification factor β ₁ ~β _N of as having 8.

  Other blocks, transmission response matrix H estimation pilot signal generation means 1-1, signal multiplexing means 1-2-1 to 1-2-N, frequency conversion means 1-3-1 to 1- 1 in radio signal transmission apparatus 1 3-N, variable amplifiers 1-4-1 to 1-4-N, transmitting antennas 1-5-1 to 1-5-N, and receiving antennas 2-1-1 to 2-1 in the radio signal receiving apparatus 2 -M, frequency conversion means 2-2-1 to 2-2M, and MIMO channel demodulation means 2-4 operate in exactly the same way as in the first embodiment.

In the MIMO radio signal transmission apparatus according to the second embodiment, | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR is calculated by the radio signal reception signal 2, and thus | W _j (N ₁ , n ₂ ,... N _M ; H) | ^{2 The} hardware configuration of the radio signal transmission device is reduced compared to the MIMO radio signal transmission device according to the first embodiment in which the radio signal transmission signal 1 calculates _AVR. can do.

  Therefore, for example, in a wireless communication system in which the wireless signal transmission device 1 is a mobile station and the wireless signal reception device 2 is a base station, the hardware load on the mobile station side can be reduced by the second embodiment.

  The MIMO wireless signal transmission apparatus according to the third embodiment is based on the TDD transmission in the MIMO wireless signal transmission apparatus according to the first embodiment, and the transfer response matrix received from the wireless signal receiving apparatus 2 by the wireless signal transmitting apparatus 1 H is transmitted from each of the reception antennas 2-1-1 to 2-1 -M from the wireless signal receiving device 2 so that the pilot signal for estimating the transmission response matrix H is transmitted, so that the wireless signal transmitting device 1 itself transmits the transmission response matrix. It is characterized by estimating H.

  The transmission response matrix H required in the transmission power control method performed by the wireless signal transmission device is the transmission response matrix H in the direction from the wireless signal transmission device 1 to the wireless signal reception device 2, but can be estimated by the wireless signal transmission device 1-1. The transfer response matrix H is a transfer response matrix H in the direction from the radio signal receiver 2 to the radio signal transmitter 1.

  However, in the case of TDD transmission, since the same frequency is used in the direction from the radio signal transmission device 1 to the radio signal reception device 1 and from the radio signal reception device 2 to the radio signal transmission device 1, the radio signal transmission device 2 to the radio signal transmission device. The transmission response matrix H in one direction and the transmission response matrix H in the direction from the radio signal transmitting apparatus 1 to the radio signal receiving apparatus 2 are equal.

  Therefore, the wireless signal transmission device 1 can also estimate the transmission response matrix H in the direction of the wireless signal reception device 2 from the wireless signal transmission device 1 necessary in the transmission power control method performed by the wireless signal transmission device.

  FIG. 2 shows a radio signal transmission device 3 and a radio signal reception device 4 included in the MIMO radio signal transmission device according to the third embodiment.

The wireless signal transmission device 3
Pilot signal generation means 1-1 for path transfer response matrix H estimation, signal multiplexing means 1-2-1 to 1-2-N, frequency conversion means 1-3-1- 3-N, variable amplifier 1-3-1 to 1-3-N, exactly the same as transmission power control means 1-7,
A pilot signal generating means 3-1, for estimating a transfer response matrix H,
N signal multiplexing means 3-2-1 to 2-3-2-N,
N frequency converting means 3-3-1 to 3-3-3,
・ N variable amplifiers 3-4-1 to 3-4-N,
Transmission power control means 3-7,
It comprises.

Further, in order to estimate the transfer response matrix H,
· N transmission / reception antennas 3-6-1 to 3-6 for receiving a transmission response matrix H estimation pilot signal transmitted from a radio signal receiver 4, which will be described later, and for transmitting the radio signal T N, Transfer response matrix H estimation means 3-7 for estimating the transfer response matrix H from the received transfer response matrix H estimation pilot signal,
N TDDs that switch the connection destinations of the transmission / reception antennas 3-6-1 to 3-6-N to the variable amplifiers 3-4-1 to 3-4-N and the transfer response matrix H estimation unit 3-7 in a time division manner Switches 3-5-1 to 3-5-N,
It comprises.

On the other hand, the radio signal receiving apparatus 4 includes frequency conversion means 2-2-1 to 2-2M, transfer response matrix H estimating means 2-3, and MIMO channel demodulating means 2-4 in the radio signal receiving apparatus 2 in FIG. Exactly the same,
・ Frequency conversion means 4-3-1 to 4-3-N
Transfer response matrix H estimation means 4-4
MIMO channel demodulation means 4-5
It comprises.

Further, so that the wireless signal transmission device 3 can estimate the transfer response matrix H,
A transfer response matrix H estimation pilot signal generating means 4-6 for generating a transfer response matrix H estimation pilot signal;
M transmission / reception antennas 4-1-1 to 4-1 -M for transmitting a transmission response matrix H estimation pilot signal and receiving the radio signal T;
The M TDD switches 4 that switch the connection destinations of the transmission / reception antennas 4-1-1 to 4-1-M to the MIMO channel demodulation unit 4-5 and the transmission response matrix H estimation pilot signal generation unit 4-6 in a time division manner. 2-1 to 4-2M,
It comprises.

  Note that the transmission response matrix H estimation means 3-7 in the wireless signal transmission apparatus 3 and the transmission response matrix H estimation pilot signal generation means 4-6 in the wireless signal reception apparatus 4 are estimated in the transmission response matrix H in the wireless signal reception apparatus 4. Means 4-4 and the path transmission response matrix H estimation pilot signal generation means 3-1 in the radio signal transmitting apparatus 3 have the same functions.

  In the radio signal receiving apparatus 4, a transmission response matrix H estimation pilot signal is generated in the transmission response matrix H estimation pilot signal generation means 4-6, and the generated transmission response matrix H estimation pilot signal is transmitted to the transmission / reception antenna 4- Send from 2-1 to 4-2-M. The signal pattern of the transfer response matrix H estimation pilot signal may be exactly the same as the pattern mentioned in the first embodiment.

  The wireless signal transmission device 3 receives the transmission response matrix H estimation pilot signal from the transmission / reception antennas 3-6-1 to 3-6-N, so that the transmission response matrix H estimation means 3-7 generates the transmission response matrix H. Can be estimated. The transmission response matrix H estimation unit 3-7 transmits the estimated transmission response matrix H to the transmission power control unit 3-8.

After the transmission response matrix H is transmitted, the transmission power control means 3-8 performs the same as in the first embodiment, and the amplification degrees β ₁ to ₁ of the variable amplifiers 1-4-1 to 1-4-N. β _N is controlled.

  The TDD switches 3-5-1 to 3-5 -N in the radio signal transmission device 3 transmit and receive antennas 3-6 when the radio signal transmission device 4 transmits the radio signal T and the pilot signal for estimating the transfer response matrix H. -1 to 3-6-N and variable amplifiers 3-4-1 to 3-4-N are connected, and when receiving a transmission response matrix H estimation pilot signal transmitted from the radio signal receiver 2, a transmission / reception antenna 3-6-1 to 3-6-N and transfer response matrix H estimation means 3-7 are connected.

  The TDD switches 4-2-1 to 4-2 -M in the radio signal receiver 4 receive and transmit the radio signal T and the transmission response matrix H estimation pilot signal transmitted by the radio signal transmitter 3. When transmitting the transmission response matrix H estimation pilot signal by connecting the 1-1-1 to 4-1-M and the MIMO channel demodulating means 4-5, A transmission signal matrix H estimation pilot signal generating means is connected.

  Other blocks, transfer response matrix H estimation pilot signal generation means 3-1, signal multiplexing means 3-2-1 to 2-3-2-N, frequency conversion means 3-3-1 to 3- 3-N, variable amplifier 3-4-1 to 3-4-N, transmission power control means 3-8, frequency conversion means 4-2-1 to 4-2-M in radio signal receiving apparatus 4, MIMO channel The demodulating means 4-5 includes a transmission response matrix H estimation pilot signal generating means 1-1, signal multiplexing means 1-2-1 to 1-2-N, and frequency converting means 1 in the wireless signal transmitting apparatus 1 of the first embodiment. -3-1 to 1-3-N, variable amplifiers 1-4-1 to 1-4-N, transmission power control means 1-7, and frequency conversion means 2-2-1 to 2 in the radio signal receiving apparatus 2 -2-M, exactly the same operation as MIMO channel demodulation means 2-5 That.

  The MIMO radio signal transmission apparatus according to the third embodiment has the MIMO radio signal transmission apparatus according to the first embodiment that receives the estimated transmission response matrix H from the radio signal receiving apparatus because the radio signal transmission apparatus itself estimates the transmission response matrix H. Compared with the signal transmission device, the wireless signal transmission device can obtain the transfer response matrix H of actual propagation more instantaneously.

Therefore, in the MIMO radio signal transmission apparatus according to the third embodiment, the transmission power can be controlled using the more recent transfer response matrix H, so that the average value (SNR _j ) _AVR is kept constant with respect to the fluctuation of the transfer response matrix H. It is possible to perform control with higher accuracy.

As described above, according to the MIMO radio signal transmission apparatuses according to the first to third embodiments, in MIMO transmission, the noise power | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR is acquired, and the transmission power _j is proportional to the noise power | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR. to amplify the power of the radio signal t _j, regardless of the transmission response matrix H, it is possible to keep the average SNR _j after demodulation processing of the radio signal receiving apparatus constant. Therefore, according to the MIMO radio signal transmission apparatus according to the first to third embodiments, the movement that the reception SNR cannot be kept constant by the conventional transmission power control that controls the transmission power value based on the reception power is not possible. A stable wireless communication service can be provided also in MIMO transmission by wireless communication.

Further, the difference between the first embodiment, the second embodiment, and the third embodiment is that noise power after demodulation processing on the wireless signal receiving device side by the wireless signal transmitting device | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR is in the method of acquisition.

The MIMO wireless signal transmission apparatus according to the first embodiment is notified of the estimated transmission response matrix H from the wireless signal receiving apparatus, and thus the noise power | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR is calculated.

On the other hand, in the MIMO radio signal transmission apparatus according to the second embodiment, the radio signal receiving apparatus calculates noise power | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR, and calculates the calculated noise power. | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR is notified to the radio signal apparatus. Therefore, since the function of calculating the noise power | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR can be deleted from the radio signal transmission apparatus, the MIMO radio signal transmission apparatus according to the first embodiment. In addition, it is possible to reduce the hardware configuration of the wireless signal transmission device. Therefore, according to the MIMO radio signal transmission apparatus according to the second embodiment, the hardware configuration on the mobile station side can be reduced in a radio communication system in which the radio signal transmission apparatus is a mobile station and the radio signal reception apparatus is a base station.

On the other hand, in the MIMO radio signal transmission apparatus according to the third embodiment, on the premise of TDD transmission, the radio signal transmission apparatus itself estimates the transfer response matrix H, and based on the estimated transfer response matrix H, the noise power | W _j (n ₁ , n ₂ ,... N _M ; H) | ² _AVR is calculated. Therefore, compared with the MIMO radio signal transmission apparatus according to the first embodiment, the radio signal transmission apparatus can acquire the transfer response matrix H of the actual propagation environment more instantaneously. SNR _j ) Control to make _AVR constant can be performed with higher accuracy.

FIG. 3 is a block configuration diagram of a radio signal transmission device 1 and a radio signal reception device 2 included in a MIMO radio signal transmission device according to a first embodiment and a second embodiment. FIG. 9 is a block configuration diagram of a radio signal transmission device 1 and a radio signal reception device 2 included in a MIMO radio signal transmission device according to a third embodiment. In the Example of this invention, it is the figure which showed an example of the structure method of the pilot signal which implement | achieves estimation of the transfer response matrix H. The concept of the transmission power control method performed by the MIMO radio signal transmission apparatus according to the embodiment and the SNR of the mobile station when the transmission power control method performed by the MIMO radio signal transmission apparatus according to the embodiment is applied to MIMO transmission qualitatively. It is the shown graph. It is the figure which showed the concept of the conventional transmission power control method. It is the graph which showed qualitatively the SNR of the mobile station at the time of applying the conventional transmission power control method to MIMO transmission.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Radio signal transmitter 1-1 Pilot signal production | generation means 1-2-1 to 1-2-N for transfer response matrix H estimation Signal multiplexing means 1-3-1 to 1-3-N Frequency conversion means 1-4 1-1-4-N variable amplifier 1-5-1 to 1-5-N transmitting antenna 1-6 receiving antenna 1-7 received signal demodulating means 1-8 transmission power control means 2 radio signal receiving apparatus 2-1 1-2-1-M Receiving antenna 2-2-1 to 2-2-2M Frequency converting means 2-3 Transfer response matrix H estimating means 2-4 MIMO channel demodulating means 2-5 Modulating means 2-6 Transmitting antenna 3 Radio signal transmission device 3-1 Transmission response matrix H estimation pilot signal generation means 3-2-1 to 2-3-2-N Signal multiplexing means 3-3-1 to 3-3-N Frequency conversion means 3-4-1 3-4-N Variable amplifier 3-5-1 to 3-5-N TDD switch 3-6 -1 to 3-6-N transmission / reception antenna 3-7 transmission response matrix H estimation means 3-8 transmission power control means 4 radio signal reception device 4-1-1 to 4-1-M transmission / reception antenna 4-2-1 4-2M TDD switch 4-3-1 to 4-3-M Frequency converting means 4-4 Transfer response matrix H estimating means 4-5 MIMO channel demodulating means 4-6 Pilot signal generating means for estimating transfer response matrix H

Claims (3)

N (N ≧ 2) transmission antennas, and using the same frequency from the N transmission antennas, radio signals T (T = (t ₁ , t ₂ ,..., T _N ) ^t , t Is a transposed vector, _i of ti is a transmitting antenna number),
M (M ≧ 1) receive antennas, and N × M radio path transfer response matrices H (H, (i, N), which are combinations of the N transmit antennas and the M receive antennas. j) The component h _ij can estimate the transmission response between the transmitting antenna j and the receiving antenna i), and M received signals R (R = (r ₁ , r ₂ ,..., r _M ) ^t , t is a transposed vector, _j of r _j is a receiving antenna number), and demodulation processing W _j (r ₁ , r ₂ ,..., r _M ; H) (1 ≦ j) determined based on the estimated transfer response matrix H ≦ N) to restore the original radio signal t _j (t _j = W _j (r ₁ , r ₂ ,... R _M ; H)),
In an N × M MIMO radio signal transmission apparatus comprising:
The wireless signal receiving device comprises means for constantly notifying the estimated transmission response matrix H to the wireless signal transmitting device;
The radio signal transmitting device is:
The demodulation processing Wj (r ₁ , r ₂ ,... R _M ; H _all ) for an arbitrary transfer response matrix H _{all in the} radio signal receiving apparatus and a receiving branch connected to each receiving antenna in the radio signal receiving apparatus Means for making known the thermal noise power of
In the radio signal receiving apparatus, the notified transfer response matrix H, the known demodulation process W _j (r ₁ , r ₂ ,... R _M ; H) and the known thermal noise power are used. The noise power a _j after the demodulation processing W _j (r ₁ , r ₂ ,..., R _M ; H) is calculated, and the j-th transmission power of the transmission antenna is proportional to the calculated noise power a _j. Means for controlling
Comprising
A MIMO radio signal transmission apparatus characterized by the above. N (N ≧ 2) transmission antennas, and using the same frequency from the N transmission antennas, radio signals T (T = (t ₁ , t ₂ ,..., T _N ) ^t , t Is a transposed vector, _i of ti is a transmitting antenna number),
M (M ≧ 1) receive antennas, and N × M radio path transfer response matrices H (H, (i, N), which are combinations of the N transmit antennas and the M receive antennas. j) The component h _ij can estimate the transmission response between the transmitting antenna j and the receiving antenna i), and M received signals R (R = (r ₁ , r ₂ ,..., r _M ) ^t , t is a transposed vector, _j of r _j is a receiving antenna number), and demodulation processing W _j (r ₁ , r ₂ ,..., r _M ; H) (1 ≦ j) determined based on the estimated transfer response matrix H ≦ N) to restore the original radio signal t _j (t _j = W _j (r ₁ , r ₂ ,... R _M ; H)),
In an N × M MIMO radio signal transmission apparatus comprising:
The radio signal receiving device is:
The demodulation processing W _j (r ₁ , r ₂ ,... R _M ; H _all ) for the estimated arbitrary transfer response matrix H _all and the thermal noise power of the reception branch connected to each reception antenna are known. Means to
In the radio signal receiving apparatus, the estimated transfer response matrix H, the known demodulation process W _j (r ₁ , r ₂ ,... R _M , H _all ) and the known thermal noise power are used. The noise power a _j after the demodulation processing W _j (r ₁ , r ₂ ,..., R _M ; H) is calculated, and the calculated noise power a _j is steadily notified to the radio signal transmitting apparatus. Means,
Comprising
The radio signal transmission device includes means for controlling the j-th transmission power of the transmission antenna in proportion to the notified noise power a _j .
A MIMO radio signal transmission apparatus characterized by the above. N (N ≧ 2) transmission antennas, and using the same frequency from the N transmission antennas, radio signals T (T = (t ₁ , t ₂ ,..., T _N ) ^t , t Is a transposed vector, _i of ti is a transmitting antenna number), and a radio signal transmitting apparatus that transmits the TDD method,
M (M ≧ 1) receive antennas, and N × M radio path transfer response matrices H (H, (i, N), which are combinations of the N transmit antennas and the M receive antennas. j) The component h _ij can estimate the transmission response between the transmitting antenna j and the receiving antenna i), and M received signals R (R = (r ₁ , r ₂ ,..., r _M ) ^t , t is a transposed vector, _j of r _j is a receiving antenna number), and demodulation processing W _j (r ₁ , r ₂ ,..., r _M ; H) (1 ≦ j) determined based on the estimated transfer response matrix H ≦ N) to restore the original radio signal t _j (t _j = W _j (r ₁ , r ₂ ,... R _M ; H)),
In an N × M MIMO radio signal transmission apparatus comprising:
The radio signal receiving device comprises means for constantly transmitting a pilot signal,
The radio signal transmitting device is:
The transmission response matrix H is estimated by receiving the pilot signal, and the demodulation processing W _j (r ₁ , r ₂ ,... R _M ; H of the radio signal reception apparatus for an arbitrary transmission response matrix H _{all all} ) and the thermal noise power of the receiving branch connected to each receiving antenna in the radio signal receiving device;
In the radio signal receiving apparatus, the estimated transfer response matrix H, the known demodulation processing W _j (r ₁ , r ₂ ,... R _M ; H _all ) and the known thermal noise power are used. The noise power a _j after the demodulation processing W _j (r ₁ , r ₂ ,..., R _M ; H) is calculated, and the j-th transmission power of the transmission antenna is proportional to the calculated noise power a _j. Means for controlling
Comprising
A MIMO radio signal transmission apparatus characterized by the above.