WO2010009580A1

WO2010009580A1 - Method and device for channel characteristics test and communication in mimo system

Info

Publication number: WO2010009580A1
Application number: PCT/CN2008/001371
Authority: WO
Inventors: 童辉; 金珊; 沈钢; 陈继明
Original assignee: 上海贝尔阿尔卡特股份有限公司; 阿尔卡特朗讯
Priority date: 2008-07-25
Filing date: 2008-07-25
Publication date: 2010-01-28
Also published as: CN102067477B; CN102067477A

Abstract

The invention provides a method for channel characteristics test and communication in MIMO system. A transmitter allocates transmitting power of pilot signals corresponding to different transmitting directions based on channel statistical characteristics between transmitting antennas and receiving antennas, and a receiver determines channel state information according to the pilot signals, such that the precision of the channel characteristics test is optimized and the system performance is improved. Also a part of pilot signals which contribute little to the channel characteristics test can be replaced with data signals, such that the system throughput can yet be increased.

Description

Channel characteristics test in MIMO systems

And communication method and device

The present invention relates to multiple input multiple output (MIMO) systems, and more particularly to methods and apparatus for channel characteristic testing and communication in MIMO systems. Background technique

Pilots are a very important aspect of system design in many mature or evolving communication standards. A good pilot design will enable accurate estimation of channel parameters and thus improve system throughput and/or bit error performance. However, the pilot also consumes radio access resources, such as frequency subcarriers and time slots. In other words, the pilot also causes system overhead.

In MIMO systems, the overhead caused by pilots can be significant. In theory, as the number of transmit and receive antennas increases, system throughput will also increase. However, in practical systems, as the number of transmitting and receiving antennas increases, the estimated channel coefficients also increase, and the proportion of pilot overhead in the total time-frequency resources of the system also increases, so when the transmitting and receiving antennas exceed At a certain number, there may even be cases where the system throughput does not rise and fall. Clearly, pilot overhead can be a bottleneck in MIMO system throughput.

For this and other purposes, a technique is needed to increase system throughput in a MIMO system. Summary of the invention

For a frequency domain flat fading, temporal block fading, spatially correlated MIMO system, the relationship between input and output can be expressed as

Y = HX + N

Wherein, the signal is transmitted, the dimension is N _T x N _s ; y is the received signal, the dimension is N _R N _s ; H is the channel transmission matrix, the dimension is N _R x N _T ; N is white noise, the dimension is confirmed The degree is N _R x N _s . Here, N _R , N _T , and N _s represent the number of receiving antennas, the number of transmitting antennas, and the transmission (reception) signal time domain (symbol) length, respectively, and the time length of satisfying N _s signals is smaller than the channel coherence time.

In the "Transmit Signal Design for Optimal Estimation of Correlated MIMO Channels, IEEE Transactions on Signal Processing, vol. 52, No. 2, February 2004", the relevant MIMO channel The form of the transmitted signal for optimizing the channel test under conditions is studied, which is hereinafter referred to as Document 1. In Document 1, the relevant channel model used is a virtual channel representation (VCR), which corresponds to

H = U _R " {H _lld ® M)U _T

Where U _R and ^ are complex 酉 matrices of two dimensions N _R x N _R and N _T x N _T respectively; H" _d represents a complex Gaussian matrix of elements with independent identically distributed ( iid ) ; Λ denotes a mask matrix in which all elements are non-negative real numbers; H,, and M have dimensions of N _R x N _T ; where ® represents the matrix Hadamard product, (representing Hermitian transpose) ( Hermitian transpose ) The specific content of the VCR channel model can be found in the literature "Deconstructing Multiantenna Fading Channels", IEEE Transactions on

Signal Processing, vol. 50, No. 10, October 2002", which is hereinafter referred to as Document 2.

According to the results of the literature 1, in the case where ^, ^ and are known at the transmitting end, if the total power of the transmitted signal used for channel testing is limited, the minimum mean square error is used.

(MMSE) and conditional mutual information (CMI) are two types of standards that obtain the optimized channel test accuracy of the transmitted signal ^ in a similar form, as shown in the following equation

X = U"D ',

Where is a diagonal matrix in which all elements are non-negative real numbers.

The intuitive physical interpretation of the signal form of the above-mentioned transmitted signal for optimizing channel test accuracy is "beam scanning", ie: the first in the signal Symbol, the transmitter distributes part of the power of the signal to the "transmitting direction" corresponding to the first column of ^; in the second symbol of the signal, the transmitter assigns a portion of the remaining power of the signal to the second corresponding to ^ The "emission direction" of the column; in the signal; other symbols of if, repeat similar operations until the entire space spanned by the columns "translated" by the transmitter. According to the content of Document 2, each column of ^ corresponds to the eigenvector of the channel covariance matrix. The channel covariance matrix is normalized to obtain the channel correlation matrix. Sometimes, for the convenience of operation, the correlation matrix will be used. Those skilled in the art will appreciate that the channel covariance matrix and the channel correlation matrix are essentially the same. The "transmitting direction" corresponding to a column of ^ here means: When transmitting a signal, the column data of ^ is applied as a weighting factor to the beam direction formed by each transmitting antenna.

Document 1 gives the results of the above diagonal matrix D in several specific cases:

1) For an independent fading channel, there is always an identity matrix. This means that all directions of transmission are of equal importance and require an even distribution of power.

2) In the case of progressively low signal-to-noise ratio (SNR), only one element is positive and the rest are zero. The only positive element in Z) is determined according to the following rules. Order

w,, _n ■■■ m, _Nr

m ₂₁ m ₂₂ · · · m _2N

M = .

― , ^m N _R l ^m N _R N _T _

And there are m = m-, ∑ i ) ² ∑ ₂ ) ² ... ∑( ^w " ) ² .

Under the two conditions of maximum condition mutual information and minimum mean square error, the index numbers of positive elements correspond to the index numbers of the maximum values of / 3⁄4 and medium, respectively.

Let H _v = H _lid ® , where the subscript v denotes a virtual domain. At low SNR, power is assigned to the most important direction. Each column of H _v corresponds to one direction of transmission, and based on the optimization criteria, all power will be assigned to the direction of emission corresponding to the maximum of ^.

3) In the case of multiple input single output (MISO), the power distribution of the signal corresponding to each direction of transmission corresponds to the following equation:

' Ν _τ · SNR =

p '

The above formula is generally referred to as a water injection algorithm, in which Pi corresponds to the power assigned to the i-th direction, that is, the direction corresponding to the i-th eigenvector of the channel covariance matrix, P _t . _tal signal corresponding to the total power, λ ί corresponding to the i-th eigenvalue of the channel covariance matrix, and (z) + represents whichever is greater between 0 and z.

The above conclusions in Document 1 are obtained in a narrowband MIMO system, but if the wideband MIMO system satisfies the conditions of frequency domain flat fading, time domain block fading, and spatial characteristics, the above conclusions can also be extended to wideband MIMO systems, for example, MIMO system with orthogonal frequency division multiplexing (OFDM) technology.

Take a 2 χ 1 MISO system as an example (MISO system can be used as a special case of MIMO system). The MISO system has frequency domain flat fading, time domain block fading, and spatial characteristic correlation. The relationship between input and output can be expressed as Y = ^X + N. When X uses the structure of the optimal pilot sequence composed of two pilot signals pl and p2, Document 1 gives the relationship between conditional mutual information and channel covariance matrix:

I(h; Y | X) = log(l + SNR - P^ ) + log(l + SNR■ P^) , where P ₂ represents the first and second transmission directions (corresponding to channel covariance) The power of the eigenvectors of the matrix, λ 1 and λ ₂ represent the corresponding eigenvalues. The optimum values for Pi and P ₂ can be determined by the water injection algorithm described above.艮 Obviously, if P ₂ is very small, the contribution of the second pilot signal to the channel test accuracy is much smaller than the first pilot symbol, so that the time-frequency resources occupied by the second pilot signal can be used for transmission. data.

If the pilot signal is not transmitted on the time-frequency resource corresponding to the second pilot signal and the data signal is transmitted, on the one hand, the system suffers performance loss due to the decrease in channel characteristic test accuracy. On the other hand, the system will Performance gains due to reduced overhead. In general, the above performance gains can be expressed as an increase in system throughput, which is difficult to represent with an analytical expression corresponding to data throughput.

In the above 2 x 1 MISO system, the loss of channel characteristic test accuracy can be expressed as 1. _§ (1 ₊ 5Μ? . ^ ₂ Α ₂ ). Considering that the loss of data throughput corresponding to performance loss should monotonously increase with the loss of channel characteristic test accuracy, the loss of data throughput corresponding to performance loss can be simply defined as log(l + SNR - P _{2 2} ) ₀ and the performance gain due to reduced overhead can be defined as £[l. g det(l + ^^^)]/4, where the numerator represents each state The channel capacity is passed, and the denominator 4 indicates that the channel coherence time is 4 symbols in length (this value is possible). From the above definition, it can be seen that performance loss and performance gain are both a function of SNR and channel covariance matrix.

Based on the above definitions of performance loss and performance benefit, the simulation conditions are set as follows: The system uses the MISO system of 2 χ 1 above; the channel capacity of each state uses 1000 loops; the channel correlation matrix is [1, p ; p,1 ]/2, where p is the channel correlation coefficient, which is 0.7, 0.8, and 0.9 respectively; the transmit power allocation of the pilot signals in both directions is determined by the aforementioned water injection algorithm; The performance loss and performance gains resulting from the replacement of the pilot signal with the data signal are compared, and the replacement is performed if the performance benefit is greater than the performance penalty, and the replacement is not performed if the performance benefit is less than the performance penalty. The simulation results are shown in Figure ,, where the horizontal axis is the signal-to-noise ratio (SNR), the unit is decibel (dB), and the vertical axis is the improved spectral efficiency in bps/Hz. The simulation results show that in the MIMO system, under certain conditions, replacing the pilot signal with less contribution to the channel characteristic test into the data signal can improve the overall performance of the system.

In order to improve the accuracy of channel characteristic testing in a MIMO system and improve the throughput of a MIMO system, the present invention proposes a technical scheme for channel characteristic testing and communication in a MIMO system.

According to a first aspect of the present invention, there is provided a method for communicating with a receiver in a transmitter of a MIMO system, the method comprising the steps of: a. acquiring a plurality of transmit antennas and locations in the transmitter Determining channel statistical characteristics of a plurality of transmission channels between one or more receiving antennas in the receiver; b. determining a plurality of transmission directions according to the channel statistical characteristics, and determining that the same pilot sequence respectively corresponds to the plurality of transmission directions The transmit power of the plurality of pilot signals and the order of the sequences; wherein the method further includes: I. the time-frequency resources corresponding to the pilot signals in the plurality of transmit directions in the same pilot sequence and the The receiver is notified of the transmit power and the order of the sequences.

According to a second aspect of the present invention, there is provided a method for communicating with a transmitter in a receiver of a MIMO system, the method comprising: A. obtaining the transmission from a received signal from the transmitter The time-frequency resource and the transmit power corresponding to the plurality of pilot signals in the same pilot sequence of the machine and the order of the sequences in the pilot sequence; The time-frequency resource receives the pilot signal; C. determining channel state information according to the received pilot signal and the sequence, the channel state information is used to indicate between the transmitter and the receiver The characteristics of multiple transport channels.

According to a third aspect of the present invention, there is provided a transmitting end processing apparatus for communicating with a receiver in a transmitter of a MIMO system, the transmitting end processing apparatus comprising: channel statistical characteristic obtaining means for acquiring a channel statistic characteristic of a plurality of transmission channels between a plurality of transmit antennas in the transmitter and one or more receive antennas in the receiver; pilot distribution means, configured to determine a plurality of transmission directions according to the statistical characteristics of the channel, And determining a transmit power and an arrangement structure of the plurality of pilot signals corresponding to the multiple transmit directions in the same pilot sequence, where the method further includes: a pilot-related information notification device, configured to respectively correspond to the same pilot sequence The time-frequency resource corresponding to the pilot signal in the plurality of transmission directions and the transmission power and the arrangement structure are notified to the receiver.

According to a fourth aspect of the present invention, there is provided a receiving end processing apparatus for communicating with a transmitter in a receiver of a MIMO system, the receiving end processing apparatus comprising: pilot related information acquiring means for And acquiring a time-frequency resource and a transmission power corresponding to the plurality of pilot signals in the same pilot sequence of the transmitter and an arrangement order in the pilot sequence, and receiving a signal from the transmitter; And the channel state information determining apparatus is configured to: according to the received pilot signal and the acquired transmit power corresponding to the pilot signal, and the pilot Channel order information is used to determine channel state information, the channel state information being used to indicate characteristics of a plurality of transmission channels between the transmitter and the receiver.

According to the technical solution of the present invention, the accuracy of the channel characteristic test in the MIMO system can be optimized, thereby improving the system performance. In accordance with certain preferred embodiments of the present invention, pilot signals that contribute very little to the channel characteristic test can also be replaced with data signals, thereby further increasing system throughput. DRAWINGS

A detailed description of a non-limiting embodiment, with reference to the accompanying drawings, Other features, objectives and advantages of Ming will become more apparent.

1 is a flow chart of a method for communicating with a receiver in a transmitter of a MIMO system, in accordance with an embodiment of the present invention;

2 is a flow chart of a method for communicating with a transmitter in a receiver of a MIMO system, in accordance with an embodiment of the present invention;

3 is a block diagram of a transmitting end processing device for communicating with a receiver in a transmitter of a MIMO system in accordance with an embodiment of the present invention;

4 is a structural diagram of a receiving end processing apparatus for communicating with a transmitter in a receiver of a MIMO system according to an embodiment of the present invention;

5 is a schematic diagram showing the arrangement of a plurality of pilot signals in a pilot sequence according to the present invention; FIG. 6 is a diagram showing power allocation of pilot signals corresponding to different transmission directions under different SNR conditions according to an embodiment of the present invention. Schematic diagram

Figure 7 is a schematic diagram of simulation effects in accordance with an embodiment of the present invention; wherein the same or similar reference numerals denote the same or similar step features or devices (modules). detailed description

MIMO system employs multiple _(Ν τ) transmit antennas and multiple (N _R) receive antennas for data transmission. In one conventional MIMO system, v _[tau] transmit antennas typically located in a single transmitter associated therewith and, similarly, N _R receive antennas are typically located in a single receiver and associated therewith. The MIMO system can also be effectively formed for a multiple access communication system having a base station that concurrently communicates with a plurality of mobile terminals, in which case the base station is equipped with multiple antennas, and each mobile terminal can also Equipped with one or more antennas.

To more fully utilize the capacity of the channel transmission, channel state information (CSI) for indicating link conditions can be determined (typically at the receiver) and provided to the transmitter. CSI can be classified as "complete CSI" or "partial CSI". The full CSI needs to include dimensions as value gains. The partial CSI may include, for example but without limitation, a signal to noise ratio (SNR) of the transmission channel. One of the objects of the present invention is to improve the accuracy of channel characteristic testing between a transmitter and a receiver in a MIMO system. Those skilled in the art should understand that a base station, a relay station and a mobile terminal in a MIMO system can be used as a transmitter or a receiver, and a transmitter and a receiver as both communication bases can correspond to a base station and a mobile terminal, or can correspond to a base station and a relay station, Or it may correspond to a mobile terminal and a relay station, or may also correspond to a relay station and a relay station. Without loss of generality, the following description will be made by taking a transmitter and a receiver corresponding to a base station and a mobile terminal as an example.

1 is a flow diagram of a method for communicating with a receiver in a transmitter of a MIMO system, in accordance with an embodiment of the present invention.

2 is a flow diagram of a method for communicating with a transmitter in a receiver of a MIMO system, in accordance with an embodiment of the present invention.

Referring to FIG. 1 and FIG. 2, the first aspect and the second aspect of the present invention are described as follows, where the transmitter corresponds to the base station and the receiver corresponds to the mobile terminal.

On the base station (transmitter) side:

First, in step S101, the base station (transmitter) will acquire the channel statistical characteristics of a plurality of transport channels between it and the mobile terminal (receiver). The base station referred to herein is equipped with a plurality of antennas, and the mobile terminal is equipped with one or more antennas. A specific implementation manner in which a base station acquires channel statistics characteristics of multiple transport channels between the base station and the mobile terminal includes:

1) The base station sends a pilot signal or a data signal to the mobile terminal, and the mobile terminal determines (downlink) channel state information (CSI) according to the received pilot signal or data signal, and the mobile terminal feeds the CSI to the base station, and the base station stores the time. The CSI within it determines the channel statistics characteristics accordingly.

2) The base station sends a pilot signal or a data signal to the mobile terminal, and the mobile terminal determines (downlink) channel state information (CSI) according to the received pilot signal or data signal, and the mobile terminal stores the CSI within a certain time and according to the The channel statistics feature is determined, and the mobile terminal feeds back the channel statistics characteristics to the base station.

3) The base station sends a pilot signal or a data signal to the mobile terminal, and the mobile terminal feeds back the received pilot signal or the related parameter of the data signal (for example, the received signal strength) to the base station, and the base station determines the CSI according to the received feedback parameter. The base station is stored within a certain period of time The CSI determines the channel statistics characteristics accordingly.

In the present invention, a channel characteristic test is performed between a base station and a mobile terminal by using a pilot signal. Generally, the mobile terminal needs CSI for receiving demodulation of the data signal, so it is suitable for the mobile terminal to determine the CSI, so the above embodiments 1), 2) can be adopted. In general, the change in channel statistical characteristics is much slower than the change in CSI. Therefore, if the channel statistical characteristics are determined by the mobile terminal and fed back to the base station, it will be possible to save a large amount of channel resources for feedback information. In other words, in the technical solution of the present invention, the base station

(Transmitter) The above embodiment 2) will preferably be employed to obtain CSI. It should be understood by those skilled in the art that the CSI referred to in the present invention refers to instantaneous CSI, and preferably, the CSI in the present invention should be a complete CSI.

In step S102, the base station determines a plurality of transmission directions according to channel statistical characteristics, and determines transmission powers and arrangement orders of the plurality of pilot signals respectively corresponding to the plurality of transmission directions in the same pilot sequence.

According to the content of Reference 1, the relationship between input and output in a MIMO system can represent ^JY according to a virtual channel representation (VCR), wherein the channel transmission matrix can be expressed as H = (H _D ® M) U _T . According to Document 1 The results of the study, in the case where the transmitter knows ^, ί/ and M, the transmitted signal with the optimized channel test accuracy obtained by the two criteria of minimum mean square error and maximum condition mutual information has a similar form, as follows X = U _T ^H D where is a diagonal matrix of all elements being non-negative real numbers. Regarding the signal form of the above-mentioned transmitted signal for optimizing channel test accuracy, the intuitive physical interpretation is "beam scanning", ie: at the first symbol of the signal, the transmitter distributes part of the power of the signal to correspond to The "transmitting direction" of the first column of the signal; in the second symbol of the signal, the transmitter distributes a portion of the remaining power of the signal to the "transmitting direction" corresponding to the second column of 7 ₇ ; other symbols in the signal , similar operation is repeated until the transmitter "scan" through the (/ _7. the columns spanned the entire space.

Specifically, in the present invention, when the base station acquires the channel statistical characteristics between it and the mobile terminal, it can determine the ^, ^ and correspondingly according to the channel statistical characteristics. 4 According to the research results of Document 1, under some standards (minimum mean square error or maximum condition mutual information), the optimal pilot structure used to optimize the channel characteristic test accuracy is a pilot sequence. The (symbol) length of the frequency sequence is equal to the number of transmit antennas (Ν _τ ), and the transmit directions of the pilot signals (symbols) in the pilot sequence correspond to the respective columns of ^. In the present invention, the base station may determine multiple transmission directions according to channel statistical characteristics, more specifically according to ^, and determine transmission power and arrangement of multiple pilot signals corresponding to multiple transmission directions in the same pilot sequence. order.

Specifically, in the present invention, the base station may preferably allocate the transmission power of the plurality of pilot signals corresponding to the plurality of transmission directions in the same pilot sequence in the following manner:

1) For an independent fading channel, the base station equally distributes power for a plurality of pilot signals respectively corresponding to a plurality of transmission directions.

2) In the case of low signal-to-noise ratio (SNR), the base station allocates all pilot powers to one pilot signal in the pilot sequence. The order of the pilot signals in the pilot sequence can be determined in the following manner. Order

m m. m

m m m

M

m and have m = m-, = ∑ i ) ² ∑ ₂ ) ∑(m _nNT ) ²

Under the two conditions of maximum condition mutual information and minimum mean square error, the sequence numbers of the pilot signals allocated to all pilot powers in the pilot sequence correspond to the index order of the maximum values in /3⁄4 and ^, respectively.

3) In the case of multiple input single output (MISO), that is, when the base station is equipped with multiple antennas and the mobile terminal is only equipped with one antenna, the base station corresponds to multiple transmission directions in the same pilot sequence respectively. The allocation of the transmission power of the plurality of pilot signals corresponds to the next

The above formula is generally referred to as a water injection algorithm, in which Pi corresponds to the transmission power, P _t , assigned to the pilot signal corresponding to the i-th direction. _Tal corresponds to the total power of the pilot signal, corresponding to the ith eigenvalue of the channel covariance matrix, and (z)+ represents a larger value between ₂ and 0.

The power allocation modes of the pilot signals used in the above three cases are all optimal modes, and some simplified suboptimal methods can be adopted in the actual system. Referring to FIG. 5, taking a 4×2 MIMO system using orthogonal frequency division multiplexing (OFDM) technology as an example, that is, the base station is equipped with 4 antennas and the mobile terminal is equipped with 2 antennas, and the preferred pilot sequence should be A pilot sequence of 4 signals (symbols), which are respectively labeled as pl, p2, p3, p4, and their respective transmit powers are P, P ₂ , P ₃ , P _{4 , respectively} . The four pilot signals may correspond to different subcarriers of the same time slot, may also correspond to the same subcarrier of different time slots, and may also correspond to different subcarriers of different time slots, as long as the four pilot signals correspond to The time-frequency resources (time-frequency points) have similar transmission characteristics. Generally, a radio channel corresponding to a time-frequency block for transmitting data can satisfy the characteristics of frequency domain flat fading and time domain block fading, and thus each time-frequency point in the time-frequency block has similar transmission characteristics. In other words, the allocation of each pilot signal in the pilot sequence in the present invention has no special requirement for the design of the pilot pattern, that is, the allocation of each pilot signal in a pilot sequence in the present invention can be A variety of existing pilot pattern designs are combined.

In step S105, the base station notifies the mobile terminal of the time-frequency resources, the transmit power, and the order of the corresponding pilot signals corresponding to the plurality of transmit directions in the same pilot sequence. Still taking a 4×2 MIMO system using OFD1V as an example, one pilot sequence corresponds to four pilot signals pl, p2, p3, and p4, and the time-frequency resources corresponding to the pilot signals are determined. After transmitting power and the order of the sequences in the pilot sequence, the base station will inform the mobile terminal of the relevant information. Specifically, in the digital communication system, the above information about the pilot signals can be represented by corresponding code segments. For example, the time-frequency resources corresponding to pl, p2, p3, and p4 are respectively indicated by four time-frequency resource code segments; the power level is digitally quantized, and the four transmit power code segments respectively indicate pl, p2, p3, and p4. Corresponding transmit power; the order of the pl, p2, p3, and p4 in the pilot sequence is indicated by the four sequence code segments. Typically, the four code segments can be 00, 01 respectively. , 10, 11. Those skilled in the art should understand that the above information about the pilot signal may be notified to the mobile terminal via a message, or may be notified to the mobile terminal via multiple messages.

On the mobile terminal (receiver) side:

In step S201, the mobile terminal will acquire the received signal from the base station. Time-frequency resources and transmit power corresponding to a plurality of pilot signals in the same pilot sequence of the base station and an order of arrangement in the pilot sequence. Specifically, taking the pilot sequence including the pilot signals pl, p2, p3, and p4 as an example, the mobile terminal can identify the time-frequency resource code segment and the transmit power corresponding to each of pl p2, p3, and p4 from the received signal. The code segment and the sequence code segment are arranged to obtain the time-frequency resources, the transmission power, and the order of the sequences in the pilot sequence, respectively, corresponding to pl, p2>p3, and p4.

In step S202, the mobile terminal will receive the pilot signal at the time-frequency resource. Specifically, the mobile terminal considers the signals received on the respective time-frequency resources corresponding to pl, p2, p3, and p4 as the received pilot signals pl, p2, p3, and p4.

In step S203, the mobile terminal will determine the CSI based on the received pilot signal and the acquired. Specifically, the mobile terminal combines the received pilot sequence according to the sequence of the received pilot signals and the received pilot signals pl, p2, p3, and p4, and according to the received pilot sequence. The CSI is determined by the respective transmit powers corresponding to pl, p2, p3, and p4, and the CSI is used to indicate characteristics of multiple transport channels between the base station and the mobile terminal.

According to a preferred embodiment of the present invention, the mobile terminal will determine channel statistical characteristics based on the current CSI and a plurality of CSIs within a predetermined time period. In various communication standards, a certain frame period is usually defined. Typically, the mobile terminal can calculate CSI in each frame period and perform statistical average on CSI in a predetermined time to determine channel statistics. It should be understood by those skilled in the art that the channel statistical characteristics described herein refer to channel statistical characteristics in the latest period of time, and the CSI used to determine the statistical characteristics of the channel should be the CSI in the latest period of time. Typically, the mobile terminal can determine the channel statistical characteristics by using a sliding time window, that is, the mobile terminal performs statistical average on the CSI in a sliding time window to determine a channel statistical characteristic, and the sliding time window should be appropriately selected. Not too big or too small. Specifically, the mobile terminal may update the channel statistics feature every time a new CSI is determined, that is, each frame, for example, the size of the sliding time window is selected as 100 frames. When the mobile terminal determines the current CSI, the mobile terminal according to the current CSI and the The first 99 CSIs stored (100 CSI total) are used to determine the channel statistics. or, The mobile terminal can also update the channel statistics feature in a longer period. For example, the sliding window size is selected as 50, and the mobile terminal can determine the channel statistical characteristics according to the CSI of the first frame to the 50th frame, and according to the 51st frame to the The CSI of 100 frames is used to determine the next channel statistics feature for update, and so on. Alternatively, the mobile terminal may update the channel statistics feature irregularly. Those skilled in the art should be able to think of other specific ways for determining the statistical characteristics of the channel according to the above description, and details are not described herein again.

According to the above preferred embodiment, the mobile terminal also needs to inform the base station of the channel statistical characteristics for the base station to allocate power for the pilot signal. Specifically, if the mobile terminal uses a period (for example, a period of 50 frames) to update the channel statistical characteristics, the mobile terminal may notify the base station of the updated channel statistical characteristics after each update of the channel statistical feature; or may move The period and sliding time window of the terminal update channel statistical characteristic are selected to be different lengths. For example, the mobile terminal updates the channel statistical characteristic by 50 frames, and the size of the sliding time window for determining the channel statistical characteristic is selected as 100 frame periods. If the mobile terminal adopts a fixed-length sliding time window and updates the channel statistical characteristics every time a new CSI is determined (ie, every frame), because of the statistical average effect, the difference between the statistical characteristics of the adjacent two updated channels will be Very small; then, when the channel statistical feature of the nthth update is notified to the base station by the mobile terminal, the mobile terminal can compare the channel statistical characteristics of each update afterwards with the channel statistical characteristics of the nth update, if the difference between the two If less than a predetermined degree, the mobile terminal does not notify the base station of the updated channel statistical characteristics; until the difference between the channel statistical characteristic of the nth (n2 is greater than nl) update and the channel statistical characteristic of the nthth update exceeds a predetermined degree, The mobile terminal notifies the base station of the channel statistical characteristics of the nth update, and then the mobile terminal compares the channel statistical characteristics of each subsequent update with the channel statistical characteristics of the nth update, and the subsequent processing is similar to the foregoing, and is not described again. .

Correspondingly, after receiving the updated channel statistical characteristics, the base station performs power allocation of the subsequent pilot signals according to the updated channel statistical characteristics. In particular, in the initial stage when the base station and the mobile terminal start the communication connection, the mobile terminal has not determined enough CSI to determine the channel statistical characteristics, and the set channel statistics feature that the base station can initialize is used for pilot signal power allocation, typically Ground, the initially set channel statistics feature can correspond to An independent fading channel, correspondingly, the base station initially allocates equal power for pl, p2, p3, p4.

The first aspect and the second aspect of the present invention are described above with reference to FIGS. 1 and 2. According to the above embodiment, the accuracy of the channel characteristic test between the base station and the mobile terminal is optimized, thereby being improved. System performance. .

It should be understood by those skilled in the art that, in general, a pilot signal having a large transmission power contributes a large amount to a channel characteristic test, and a pilot signal having a small transmission power contributes less to a channel characteristic test. For pilot signals that contribute very little to the channel characteristics test, using the time-frequency resources it occupies to retransmit the data will likely improve the overall performance of the system. According to a preferred variant of the above embodiment, after step S102, the base station will also perform other steps.

In step S103, the base station estimates, according to the channel statistical characteristics and the transmit powers of the plurality of pilot signals respectively corresponding to the plurality of transmit directions in the same pilot sequence, one of the plurality of pilot signals having a smaller transmit power. The performance loss and performance gain caused by the replacement of multiple pilot signals with data signals. Specifically, the respective transmit powers of the pilot signals pl, p2, p3, and p4 are respectively P, P ₂ , P ₃ , and P ₄ , and there are P^P^P^P^ according to a preferred embodiment, the base station It will first estimate the performance loss and performance benefit of replacing p4 with the data signal, then estimate the performance loss and performance benefit of replacing p4, p3 with the data signal, and then estimate to replace p4, p3, p2 with the data signal. The resulting performance loss and performance gains are then estimated by replacing p4, p3, p2, pi with performance loss and performance gains from the data signal. The estimates here can be based on empirical formulas derived from statistical data. In general, replacing a pilot signal with a large transmit power into a data signal will inevitably result in a decrease in the overall performance of the system. Therefore, only one of the transmit power or the ratio of the transmit power to the total power of the pilot signal may be less than a predetermined value or The plurality of pilot signals are subjected to the above estimation, and the predetermined value can be reasonably set according to empirical data to avoid an increase in the amount of system operation caused by excessive unnecessary estimation. For example, if both P ₃ and P ₄ are smaller than a predetermined value, the base station can estimate the performance loss and performance benefit caused by replacing p4 and p3 with the data signal, and can also estimate only the performance loss and performance benefit caused by replacing p4 with the data signal. It is also possible to estimate only the performance loss and performance benefit of replacing p3 with data signals. In step S104, if it is estimated that the performance gain caused by replacing the one or more pilot signals with the smaller transmit power into the data signal is higher than the performance loss, the base station transmits the one or more of the transmit powers to be smaller. The pilot signals are replaced with data signals.

Correspondingly, in step S105, the base station further needs to notify the mobile terminal of the time-frequency resource and/or the transmit power corresponding to the data signal for replacing the one or more pilot signals with the smaller transmit power.

Accordingly, the mobile terminal will determine the CSI based on the received pilot signals and their corresponding transmit powers and the order in which they are arranged in the pilot sequence. For example, if the base station transmits the pilot signals pl, p2 and replaces the pilot signals p3, p4 with data, the mobile terminal will according to the received pl, p2 and its corresponding P, P ₂ and its in the pilot sequence. Sort the order to determine the CSI. Preferably, the mobile terminal may set the received power of the pilot signals p3, p4 to 0, and then set the two null signals whose received powers corresponding to pl, p2 and p3, p4 are set to 0 according to the pilot sequence. The arrangement order in the combination is combined into the received pilot sequence, and then the mobile terminal can determine the CSI according to the received pilot sequence and the transmission powers P, P ₂ , P ₃ , P ₄ corresponding to the respective signals therein. After the above processing, the time-frequency resources occupied by the pilot signals p3 and p4 are used to retransmit the data, the accuracy of the system channel characteristic test is very limited, and the system throughput is improved, thereby improving the overall performance of the system.

It should be understood by those skilled in the art that although the above description only refers to the case where the transmitter corresponds to the base station and the receiver corresponds to the mobile terminal, the base station, the relay station and the mobile terminal in the MIMO system can be used as the transmitter or the receiver. The transmitter and receiver as both communicating parties may correspond to the mobile terminal and the base station, or may correspond to the base station and the relay station, or may correspond to the mobile terminal and the relay station, or may also correspond to the relay station and the relay station.

3 is a transmitter processing apparatus for communicating with a receiver in a transmitter of a MIMO system in accordance with an embodiment of the present invention. As shown in FIG. 3, the transmitting end processing means 301 includes a channel statistical characteristic obtaining means 3011, a pilot allocating means 3012, a first estimating means 3013, a data replacing means 3014, and a pilot related information notifying means 3015. According to various embodiments of the present invention, the transmitting end processing device 301 may include some or all of the above devices, and may also include other devices. 4 is a receiver processing apparatus for communicating with a transmitter in a receiver of a MIMO system in accordance with an embodiment of the present invention. As shown in FIG. 4, the receiving end processing means 401 includes a pilot related information acquiring means 4011, a signal receiving means 4012, a channel state information determining means 4013, a channel statistical characteristic determining means 4014, and a channel statistical characteristic notifying means 4015. According to various embodiments of the present invention, the receiving end processing device 401 may include some or all of the above devices, and may also include other devices.

The third and fourth aspects of the present invention will be described below with reference to Figs. 3 and 4. Those skilled in the art will appreciate that base stations, relay stations, and mobile terminals in a MIMO system can function as a transmitter or receiver. Without loss of generality, the following description will be made taking the case where the transmitter corresponds to the base station and the receiver corresponds to the mobile terminal. The transmitting end processing device 301 is located in the base station, and the receiving end processing device 401 is located in the mobile terminal.

On the side of the base station:

First, the base station will acquire the channel statistical characteristics of a plurality of transport channels between it and the receiver by its statistical information acquiring means 3011. The base station referred to herein is equipped with a plurality of antennas, and the mobile terminal is equipped with one or more antennas. A specific implementation manner in which a base station acquires channel statistics characteristics of multiple transport channels between the base station and the mobile terminal includes:

3) The base station sends a pilot signal or a data signal to the mobile terminal, and the mobile terminal feeds back the received pilot signal or the related parameter of the data signal (for example, the received signal strength) to the base station, and the base station determines the CSI according to the received feedback parameter. The base station stores CSI within a certain time and determines channel statistical characteristics accordingly.

Referring to the foregoing description of the first aspect and the second aspect of the invention, in the present invention, A channel characteristic test is performed between the station and the mobile terminal by using a pilot signal. In general, the change in channel statistical characteristics is much slower than the change in CSI. Therefore, if the channel statistical characteristics are determined by the mobile terminal and fed back to the base station, it will be possible to save a large amount of channel resources for feedback information. In other words, in the technical solution of the present invention, the base station will preferably adopt the above embodiment 2) to acquire channel statistical characteristics. It should be understood by those skilled in the art that the CSI referred to in the present invention refers to instantaneous CSI, and preferably, the CSI in the present invention should be a complete CSI.

After the channel statistics feature is acquired by the statistical information acquiring device 3011, the base station will determine a plurality of transmission directions by the pilot allocating device 3012 according to the channel statistical characteristics, and determine a plurality of guides corresponding to the plurality of transmitting directions in the same pilot sequence. The transmit power of the frequency signal and the order of the sequences.

In the content of reference 1, the relationship between input and output in a MIMO system can represent ^JY = HX ₊ N ', according to a virtual channel representation (VCR), where the channel transfer matrix can be expressed as Η = ί^ Η ® Μ) υ _τ . Specifically, in the present invention, when the base station acquires the channel statistical characteristics between it and the mobile terminal, it can determine the ^, ^, and 相应 correspondingly according to the channel statistical characteristics. According to the research results of Document 1, under certain criteria (minimum mean square error or maximum condition mutual information), the optimal pilot structure used to optimize the channel characteristic test accuracy is a pilot sequence, the pilot sequence (symbol The length is equal to the number of transmit antennas (Ν _τ ), and the transmit directions of the pilot signals (symbols) in the pilot sequence correspond to the columns of t/, respectively. In the present invention, the base station according to the statistical properties of the channel, and more particularly according _υ τ, determining a plurality of transmit directions, a plurality of guide and determine the transmit power of the same pilot sequences respectively corresponding to a plurality of pilot signal radiation direction and Order.

Specifically, in the present invention, the pilot allocation means 3012 may preferably allocate the transmission powers of the plurality of pilot signals respectively corresponding to the plurality of transmission directions in the same pilot sequence in the following manner:

1) For the independent fading channel, the pilot allocating means 3012 equally distributes power for a plurality of pilot signals respectively corresponding to a plurality of transmission directions.

2) In the case of low signal to noise ratio (SNR), the pilot allocating means 3012 allocates all pilot powers to one pilot signal in the pilot sequence, the pilot signal being in the pilot sequence The arrangement number of 71 can be determined in the following manner. make

And have m

Under the two conditions of maximum condition mutual information and minimum mean square error, the order of the pilot signals allocated to all pilot powers in the pilot sequence respectively correspond to the index order of the maximum values in / 3⁄4 and ^

3) In the case of multiple input single output (MISO), that is, when the base station is equipped with multiple antennas and the mobile terminal is only equipped with one antenna, the pilot allocation device 3012 corresponds to the same pilot sequence respectively. The allocation of the transmission power of a plurality of pilot signals in the transmission direction corresponds to the following equation:

The above formula is generally referred to as a water injection algorithm, in which Pi corresponds to the transmission power, P _t , assigned to the pilot signal corresponding to the i-th direction. _Tal corresponds to the total power of the pilot signal, human; corresponds to the ith eigenvalue of the channel covariance matrix, and (z)+ represents a larger value between z and 0.

The power allocation modes of the pilot signals used in the above three cases are all optimal, and some simplified suboptimal methods can be adopted in the actual system.

Specifically, taking a 2 χ 1 MISO system using OFDM technology as an example, that is, the base station is equipped with two antennas and the mobile terminal is equipped with one antenna, and the MISO system has frequency domain flat fading, time domain block fading, and spatial characteristic correlation. The relationship between its input and output can be expressed as γ = /ίχ + Ν. The preferred pilot sequence in the MISO system should be a 2-signal (symbol) pilot sequence, and the two pilot signals are labeled pi, p2, respectively, and their respective transmit powers are P, P ₂ , respectively. The two pilot signals may correspond to different subcarriers of the same time slot, may also correspond to the same subcarrier of different time slots, and may also correspond to different subcarriers of different time slots, as long as the two pilot signals correspond to The time-frequency resources (time-frequency points) have similar transmission characteristics. Generally, a radio channel corresponding to a time-frequency block for transmitting data can satisfy the characteristics of frequency domain flat fading and time domain block fading, and thus each time-frequency point in the time-frequency block has similar transmission characteristics. In other words, the pilot in the present invention The allocation of each pilot signal in the sequence has no special requirement for the design of the pilot pattern, that is, the allocation of each pilot signal in one pilot sequence in the present invention can be combined with existing pilots. The pattern design scheme is combined.

Based on the foregoing description, pilot allocation device 3012 will employ the water injection algorithm described above to assign its respective corresponding transmit power P, P _{2 to} pilot signals pl, p2. The first eigenvalue of the channel covariance matrix of the MISO system is λ, and the second eigenvalue is λ ₂ , both of which are non-negative real numbers, and the person is greater than λ ₂ . 6 is a schematic diagram of pilot signal power allocation corresponding to different transmission directions under different signal to noise ratio conditions, in accordance with an embodiment of the present invention. As shown in FIG. 6, for a certain channel correlation matrix, the power allocated in different transmission directions varies with the signal to noise ratio. In the case of a high signal-to-noise ratio, the power distributed in all directions of transmission is almost equal. In the case of very low SNR, all the power is assigned to the "strongest" in the emission direction, i.e., all the power is allocated to pilot signals pi, p2 and P ₂ corresponding to 0. In the case of a general signal-to-noise ratio, a stronger beam is allocated to higher power, while a weaker beam is allocated to less power, that is, greater than P ₂ .

After the pilot allocation device 3012 determines a plurality of transmission directions, and determines transmission powers and arrangement orders of the plurality of pilot signals respectively corresponding to the plurality of transmission directions in the same pilot sequence, the base station is notified by its pilot related information. The device 3015 notifies the mobile terminal of the time-frequency resources, the transmission power, and the arrangement order corresponding to the pilot signals in the plurality of transmission directions in the same pilot sequence. Still taking the above 2 χ 1 MISO system as an example, one pilot sequence corresponds to two pilot signals pl, p2, and the time-frequency resources, the transmit power, and the pilot sequence corresponding to each pilot signal are determined. After the arrangement order in the middle, the pilot related information notifying means 3015 will notify the mobile terminal of the related information. Specifically, in the digital communication system, the above information about the pilot signals can be represented by corresponding code segments. For example, the time-frequency resources corresponding to pl and p2 are respectively indicated by two time-frequency resource code segments; the power level is digitally quantized, and the two transmit power code segments respectively indicate the transmit power P ₂ corresponding to pl and p2; The two sequential code segments respectively indicate the order in which the pl and p2 are arranged in the pilot sequence. Typically, the two sequence code segments can take values of 00 and 01, respectively. Those skilled in the art should understand that the above information about the pilot signal may be notified to the mobile terminal via a message, or The mobile terminal is notified via a plurality of messages.

On the mobile terminal side:

The pilot related information acquiring unit 4011 in the mobile terminal acquires time-frequency resources and transmit power corresponding to the plurality of pilot signals in the same pilot sequence of the base station, and the pilot sequence in the received signal from the base station. The order in which they are arranged. Specifically, taking the pilot sequence including the pilot signals pl and p2 as an example, the mobile terminal may identify a time-frequency resource code segment, a transmit power code segment, and an arrangement sequence code segment corresponding to each of pl and p2 from the received signal. Therefore, the time-frequency resources, the transmission power, and the order of arrangement in the pilot sequence corresponding to each of pl and p2 are known.

The mobile terminal will then receive the pilot signal at its time-frequency resource by its signal receiving device 4012. Specifically, the signal receiving device 4012 regards the signals received on the respective time-frequency resources corresponding to pi and p2 as the received pilot signals pl, p2.

After the signal receiving device 4012 receives the pilot signal from the time-frequency resource, the mobile terminal will determine, by its channel state information determining device 4013, the transmit power corresponding to the received pilot signal and the acquired pilot signal. And the order of arrangement in the pilot sequence to determine CSI. Specifically, the channel state information determining means 4013 combines the received pilot sequences according to the arrangement order corresponding to the received pilot signals and the received pilot signals pl, p2, and according to the received pilot sequences. The CSI is determined by a respective transmit power corresponding to pl, p2, where the CSI is used to indicate characteristics of a plurality of transport channels between the base station and the mobile terminal.

According to a preferred embodiment of the present invention, the mobile terminal will determine the channel statistical characteristics by its channel statistical characteristic determining means 4014 based on the current CSI and a plurality of CSIs in the previous predetermined time. In various communication standards, a certain frame period is usually defined. Typically, the mobile terminal can calculate CSI in each frame period and perform statistical average on CSI in a predetermined time to determine channel statistics. Those skilled in the art should understand that the channel statistical characteristics described herein refer to channel statistical characteristics in the latest period of time, and the CSI used to determine the statistical characteristics of the channel should be the CSI in the latest period of time. Typically, the mobile terminal can determine the channel statistical characteristics by means of a sliding time window, that is, the mobile terminal performs a statistical average on the CSI within a sliding time window to determine Channel statistical characteristics, the sliding time window should be properly selected, not too large or too small. Specifically, the mobile terminal may update the channel statistics feature every time a new CSI is determined, that is, each frame, for example, the size of the sliding time window is selected as 100 frames. When the mobile terminal determines the current CSI, the mobile terminal according to the current CSI and the The first 99 CSIs stored (100 CSI total) are used to determine the channel statistics. Alternatively, the mobile terminal may also update the channel statistics feature in a longer period. For example, the sliding window size is selected as 50, and the mobile terminal may determine the channel statistics according to the CSI of the first frame to the 50th frame, and according to the 51st frame. The CSI to the 100th frame is used to determine the next channel statistic for updating, and so on. Alternatively, the mobile terminal may update the channel statistics feature irregularly. Those skilled in the art should be able to think of other specific ways for determining the statistical characteristics of the channel according to the above description, and details are not described herein again.

According to the above preferred embodiment, the mobile terminal also needs to inform the base station of its channel statistical characteristics by its channel statistical characteristic notifying means 4015 for the base station to allocate power for the pilot signal. Specifically, if the mobile terminal uses a period (for example, a period of 50 frames) to update the channel statistical characteristics, the mobile terminal may notify the base station of the updated channel statistical characteristics after each update of the channel statistical feature; or may move The period and sliding time window of the terminal update channel statistical characteristic are selected to be different lengths. For example, the mobile terminal updates the channel statistical characteristic by 50 frames, and the size of the sliding time window for determining the channel statistical characteristic is selected as 100 frame periods. If the mobile terminal adopts a fixed-length sliding time window and updates the channel statistical characteristics every time a new CSI is determined, because of the statistical average effect, the difference between the statistical characteristics of the adjacent two updated channels will be Very small; then, when the channel statistical feature of the nthth update is notified to the base station by the mobile terminal, the mobile terminal can compare the channel statistical characteristics of each update afterwards with the channel statistical characteristics of the nth update, if the difference between the two If less than a predetermined degree, the mobile terminal does not notify the base station of the updated channel statistical characteristics; until the difference between the channel statistical characteristic of the nth (n2 is greater than nl) update and the channel statistical characteristic of the nthth update exceeds a predetermined degree, The mobile terminal notifies the base station of the channel statistical characteristics of the nth update, and then the mobile terminal compares the channel statistical characteristics of each subsequent update with the channel statistical characteristics of the nth update, and the subsequent processing is similar to the foregoing, and is not described again. . 1 Correspondingly, after receiving the updated channel statistical characteristics by the channel statistical characteristic receiving device 3011, the base station performs power allocation of the subsequent pilot signals according to the updated channel statistical characteristics. In particular, in the initial stage when the base station and the mobile terminal start the communication connection, the mobile terminal has not determined enough CSI for determining the channel statistical characteristics, and the base station can use the set channel statistical characteristic initialized by its channel statistical characteristic obtaining means 3011 for Pilot signal power allocation is performed. Typically, the initially set channel statistic characteristics may correspond to an independent fading channel, and accordingly, pilot allocation device 3012 initially allocates equal power for pl, p2.

The third aspect and the fourth aspect of the present invention are described above with reference to FIG. 3 and FIG. 4. According to the above embodiment, the accuracy of the channel characteristic test between the base station and the mobile terminal is optimized, thereby being improved. System performance.

It should be understood by those skilled in the art that, in general, a pilot signal having a large transmission power contributes a large amount to a channel characteristic test, and a pilot signal having a small transmission power contributes less to a channel characteristic test. For pilot signals that contribute very little to the channel characteristics test, using the time-frequency resources it occupies to retransmit the data will likely improve the overall performance of the system.

According to a preferred variant of the above embodiment, the transmitting end processing means 301 of the base station further comprises a first estimating means 3013 and a data replacing means 3014.

After the pilot allocation device 3012 determines a plurality of transmission directions according to channel statistical characteristics, and determines transmission powers and arrangement orders of the plurality of pilot signals respectively corresponding to the plurality of transmission directions in the same pilot sequence, the base station will be estimated by the first The device 3013 estimates one or more pilots that have a smaller transmit power in the multiple pilot signals according to channel statistical characteristics and transmit powers of multiple pilot signals in the same pilot sequence respectively corresponding to multiple transmit directions. The performance loss and performance benefits of replacing the signal with a data signal. Specifically, taking the pilot sequence including the pilot signals pl and p2 as an example, the respective transmit powers of the pilot signals pl and p2 are respectively P, P ₂ and P, > P ₂ . According to a preferred embodiment, the first estimating means 3013 will first estimate the performance loss and performance benefit brought by replacing p2 with the data signal, and then estimate the performance loss and performance benefit brought by replacing p2, pi with the data signal, here Estimates can be based on empirical data Style. In general, replacing a pilot signal with a large transmit power into a data signal will inevitably result in a decrease in the overall performance of the system. Therefore, only one of the transmit power or the ratio of the transmit power to the total power of the pilot signal may be less than a predetermined value or The plurality of pilot signals are subjected to the above estimation, and the predetermined value can be reasonably set according to empirical data to avoid an increase in the amount of system operation caused by excessive unnecessary estimation.

If the first estimating means 3013 estimates that the performance benefit of replacing the one or more pilot signals with the smaller transmit power into the data signal is higher than the performance loss, the base station transmits the transmit power by its data replacing means 3014. The smaller one or more pilot signals are replaced with data signals. Specifically, if the first estimating means 3013 estimates that the performance benefit of replacing p2 with the data signal is higher than the performance loss, the data replacing means 3014 replaces p2 with the data signal.

Correspondingly, the base station further needs to notify the mobile terminal by the pilot related information notifying means 3015 to replace the time-frequency resource and/or the transmission power corresponding to the data signal of the one or more pilot signals whose transmission power is small. Specifically, the pilot related information notifying means 3015 in the base station also needs to notify the mobile terminal of the time-frequency resource and/or the transmission power corresponding to the data signal of the replacement p2.

Accordingly, the channel state information determining means 4013 in the mobile terminal will replace the pilot signal p2 with data according to the reception determination CSL, for example, the base station transmits the pilot signal pi. Then, the pilot related information acquiring means 4011 in the mobile terminal acquires the time-frequency resource and the transmission power P corresponding to pi, and the order of arrangement of pi in the pilot sequence, and the signal receiving device 4012 in the mobile terminal will receive the received signal according to the received signal. The pi and its corresponding P, and their order of arrangement in the pilot sequence, determine the CSI. Preferably, the channel state information determining means 4013 may set the received power of the pilot signal p2 to 0, and then set the received power corresponding to p2 to a null signal of 0 and the received pi according to the order of the pilot sequences. The received pilot sequence is synthesized, and then the CSI is determined according to the received pilot sequence and the transmission powers P, P ₂ corresponding to the respective signals therein. After the above processing, the time-frequency resources occupied by the pilot signal p2 are used to retransmit the data, and the accuracy of the system channel special '\vi3⁄4' j is very limited, and the system throughput is improved, so that the overall performance of the system can be improved. improve. Those skilled in the art should understand that the above various devices can be implemented by using various software, hardware, and a combination of software and hardware, and various devices can be separated and merged according to the similarity or correlation of respective functions. Or a combination.

The non-limiting embodiments of the present invention have been described above, but the present invention is not limited to the specific systems, equipment, and specific protocols. Those skilled in the art can make various modifications or changes within the scope of the appended claims. .

Claims

Claim

A method for communicating with a receiver in a transmitter of a MIM0 system, the method comprising the steps of:

a. acquiring channel statistical characteristics of a plurality of transmission channels between the plurality of transmit antennas in the transmitter and one or more of the receive antennas;

b. determining a plurality of transmission directions according to the channel statistical characteristics, and determining transmission powers and arrangement orders of the plurality of pilot signals respectively corresponding to the plurality of transmission directions in the same pilot sequence;

The method further includes:

1. Notifying the receiver of the time-frequency resources corresponding to the pilot signals in the plurality of transmission directions and the transmission power and the arrangement order in the same pilot sequence.

2. The method according to claim 1, wherein the step b further comprises the following steps:

And estimating, according to the channel statistical characteristic and the transmit power of the plurality of pilot signals respectively corresponding to the multiple transmit directions in the same pilot sequence, one or more of the transmit powers of the plurality of pilot signals being smaller Replacement of pilot signals with performance loss and performance gains caused by data signals;

d. if the performance benefit of replacing the one or more pilot signals with a smaller transmit power into the data signal is higher than the performance loss, replacing the one or more pilot signals with the smaller transmit power with Data signal

The step I further includes:

The receiver is notified of a time-frequency resource and/or a transmission power corresponding to the data signal of the one or more pilot signals having a smaller transmit power.

The method according to claim 1 or 2, wherein the step a further comprises:

Receiving the channel statistical characteristic from the receiver, wherein the channel statistical characteristic is determined based on current channel state information and a plurality of channel state information in a predetermined time period.

The method according to any one of claims 1 to 3, wherein the step b further comprises:

According to the channel statistical characteristic, a water injection algorithm is used to determine transmission powers of the plurality of pilot signals respectively corresponding to the plurality of transmission directions in the same pilot sequence.

The method according to any one of claims 1 to 4, wherein the step a further comprises:

- Initially set the channel statistics feature.

The method according to any one of claims 1 to 5, characterized in that the transmitter comprises a base station, a relay station or a mobile terminal, and the receiver comprises a mobile terminal, a relay station or a base station.

7. A method for communicating with a transmitter in a receiver of a MIMO system, the method comprising: time-frequency resources and transmit power corresponding to a plurality of pilot signals in a sequence and at the pilot sequence Arrangement order

B. receiving, at the time-frequency resource, the pilot signal;

C. determining channel state information according to the received pilot signal and the transmit power corresponding to the acquired pilot signal and the order of arrangement in the pilot sequence, the channel state information being used to indicate the transmission Characteristics of multiple transport channels between the machine and the receiver.

8. The method according to claim 7, wherein the method further comprises the steps of:

i. determining channel statistical characteristics based on current channel state information and a plurality of channel state information for a predetermined time.

The method according to claim 7 or 8, wherein the method further comprises the steps of:

通知. Notifying the transmitter of the channel statistical characteristics.

The method according to any one of claims 7 to 9, wherein the transmitter comprises a base station, a relay station or a mobile terminal, and the receiver comprises a mobile terminal, Relay station or base station.

11. A transmitting end processing device for communicating with a receiver in a transmitter of a MIM0 system, the transmitting end processing device comprising:

Channel statistic feature obtaining means, configured to acquire channel statistic characteristics of a plurality of transmission channels between the plurality of transmitting antennas in the transmitter and one or more receiving antennas in the receiver;

a pilot allocation device, configured to determine a plurality of transmission directions according to the channel statistical characteristics, and determine transmit power and an arrangement structure of the plurality of pilot signals respectively corresponding to the plurality of transmission directions in the same pilot sequence;

It also includes:

a pilot-related information notification apparatus, configured to notify the receiver of a time-frequency resource corresponding to a pilot signal in a plurality of transmission directions and the transmission power and the arrangement structure in the same pilot sequence .

The transmitting end processing device according to claim 11, wherein the transmitting end processing device further comprises:

The first estimating device estimates, according to the channel statistical characteristic and the transmit power of the plurality of pilot signals respectively corresponding to the multiple transmit directions in the same pilot sequence, that the transmit power in the plurality of pilot signals is small Replacement of one or more pilot signals with performance loss and performance gains caused by data signals;

a data replacement device, configured to: if the performance benefit of replacing the one or more pilot signals with a smaller transmit power into a data signal is higher than a performance loss, the one or more pilots having a smaller transmit power The frequency signal is replaced with a data signal;

The pilot related information notification apparatus is further configured to notify the receiver of a time-frequency resource and/or a transmission power corresponding to the data signal of the one or more pilot signals that are smaller than the transmit power. .

The device for processing a transmitting end according to claim 11 or 12, wherein the channel statistical characteristic obtaining device is further configured to:

Receiving the channel statistical characteristic from the receiver, wherein the channel statistical characteristic is based on current channel state information and a plurality of channel state information in a predetermined time period To determine.

The transmitting end processing device according to any one of claims 11 to 13, wherein the pilot distributing device is further configured to:

And determining, according to the channel statistical characteristic, a transmit power of a plurality of pilot signals respectively corresponding to the plurality of transmission directions in the same pilot sequence by using a water injection algorithm.

The transmitting end processing device according to any one of claims 11 to 14, wherein the channel statistical characteristic obtaining device is further configured to:

- Initially set the channel statistics feature.

The transmitting end processing apparatus according to any one of claims 11 to 15, wherein the transmitter comprises a base station, a relay station or a mobile terminal, and the receiver comprises a mobile terminal, a relay station or a base station.

17. A receiving end processing device for communicating with a transmitter in a receiver of a MIMO system, the receiving end processing device comprising:

a pilot-related information acquiring apparatus, configured to acquire time-frequency resources and transmit power corresponding to a plurality of pilot signals in the same pilot sequence of the transmitter by a received signal from the transmitter, and in the guide The order of the sequences in the frequency sequence;

a signal receiving device, configured to receive the pilot signal at the time-frequency resource; and channel state information determining means, configured to use, according to the received pilot signal and the acquired determined channel state information, the channel state information is used A characteristic of a plurality of transmission channels between the transmitter and the receiver is indicated.

The receiving end processing device according to claim 17, wherein the receiving end processing device further comprises:

The channel statistics characteristic determining means is configured to determine channel statistical characteristics based on the current channel state information and the plurality of channel state information in the previous predetermined time.

The receiving end processing device according to claim 17 or 18, wherein the receiving end processing device further comprises:

And a channel statistics characteristic notifying means, configured to notify the transmitter of the channel statistical characteristic.

The receiving end processing apparatus according to any one of claims 17 to 19, wherein the transmitter comprises a base station, a relay station or a mobile terminal, and the receiver comprises a mobile terminal, a relay station or a base station.