WO2011035698A1

WO2011035698A1 - Method and system for processing uplink data

Info

Publication number: WO2011035698A1
Application number: PCT/CN2010/076980
Authority: WO
Inventors: 陈文洪; 缪德山; 孙韶辉; 毛博雅
Original assignee: 大唐移动通信设备有限公司
Priority date: 2009-09-27
Filing date: 2010-09-16
Publication date: 2011-03-31
Also published as: CN102013904A

Abstract

Disclosed is a method for processing the uplink data, used for improving the uplink transmission performance. The method includes: a terminal obtains a precoding matrix according to uplink statistical channel information; the uplink statistical channel information is obtained according to the downlink statistical channel information which is obtained by counting the downlink channel information by the terminal; the terminal precodes the data by means of the precoding matrix; the terminal transmits the precoded data. Disclosed is also a system for implementing the said method.

Description

The invention relates to a method and system for processing uplink data. The application is submitted to the Chinese Patent Office on September 27, 2009, and the application number is 200910093689.6.

The priority of the Chinese Patent Application, which is incorporated herein by reference. Technical field

The present invention relates to the field of communications, and in particular, to an uplink data processing method and system. Background technique

MIMO (Multiple Input Multiple Output) technology uses multiple antennas for transmitting and receiving at both the transmitting end and the receiving end, thereby greatly improving the transmission performance and capacity of the system. In the uplink transmission, in order to achieve a higher peak rate, the original UE (User Equipment) single-antenna transmission (ie, SIMO (Single Input Multiple Output)) cannot meet the requirements of future communication development. . Therefore, it is very likely that the uplink SIMO will be developed to uplink MIMO technology in the future, which is also an important step for the LTE (Long Term Evolution) system to upgrade to the Advanced-LTE system.

In the MIMO system, the existing transmit diversity modes include STBC (Space-Time Block Code) and Space-Frequency Block Code (SFBC). Both use Alamoti coding to obtain coding gain. The encoding process is shown in Figure 1 and Figure 2. Because the uplink signal transmission has higher peak-to-average ratio requirements, the peak-to-average ratio of the SFBC in Figure 2 is 4 (the unit CM in the figure is the cubic metric (Cubic Metric). )), adopting a different SFBC coding than the traditional method, and satisfying the peak-to-average ratio requirement in the case of small performance loss.

However, the existing STBC coding cannot be encoded in pairs when there are an odd number of data symbols, and special processing of the extra symbols is required, which increases the complexity and sacrifices performance. Traditional SFBC coding results in a higher peak-to-average ratio, which increases the radio frequency complexity of the terminal and affects performance. Although the SFBC coding of the low-peak-to-average ratio ensures the peak-to-average ratio, the frequency-domain correlation of the paired coded symbols is low, resulting in a certain deterioration in performance, especially the channel loss with high frequency selectivity. Simultaneously, These types of transmit diversity methods have poor performance in high-speed transmission and cannot meet the requirements. Summary of the invention

The embodiment of the invention provides an uplink data processing method and system for improving uplink transmission performance.

An uplink data processing method includes the following steps:

The terminal obtains a precoding matrix according to the uplink statistical channel information; the uplink statistical channel information is that the terminal performs downlink statistical channel information on the downlink channel information, and obtains the downlink statistical channel information according to the downlink statistical channel information;

The terminal precodes the data through a precoding matrix;

The terminal transmits the precoded data.

A terminal device, comprising:

a precoding matrix module, configured to obtain a precoding matrix according to the uplink statistical channel information; the uplink statistical channel information is obtained by performing statistics on the downlink channel information to obtain downlink statistical channel information, and obtaining the downlink statistical channel information according to the downlink statistical channel information;

a precoding module, configured to precode data through a precoding matrix;

An interface module, configured to send pre-coded data.

In the embodiment of the present invention, the uplink channel information is obtained by using the downlink downlink channel information, and the precoding matrix is obtained according to the uplink channel information, and the uplink data is further precoded to implement uplink closed loop transmit diversity, and the existing transmit diversity mode. It has better performance and is suitable for high speed environments. DRAWINGS

1 is a schematic diagram of a STBC encoding process in the prior art;

2 is a schematic diagram of a SFBC encoding process with a low peak-to-average ratio in the prior art;

3 is a structural diagram of a communication system according to an embodiment of the present invention;

4 is a structural diagram of a terminal device according to an embodiment of the present invention; FIG. 5 is a flowchart of a method for processing uplink data in an embodiment of the present invention;

6 is a flowchart of an uplink data processing method when downlink channel information is a downlink channel correlation matrix according to an embodiment of the present invention;

7 is a flowchart of an uplink data processing method when downlink channel information is a downlink channel covariance matrix according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of performance comparison in an embodiment of the present invention. detailed description

In the embodiment of the present invention, the uplink channel information is obtained by using the downlink downlink channel information, and then the precoding matrix is obtained according to the uplink channel information, and the data is precoded by using the precoding matrix, thereby implementing closed loop transmit diversity, and the existing open loop Compared to sending diversity, there is better transmission performance.

Referring to FIG. 3, the communication system in this embodiment includes a terminal 301 and a base station 302. The base station 302 can be an evolved base station (eNB) or the like.

The terminal 301 is configured to perform downlink channel estimation according to the downlink reference signal, obtain downlink channel information, perform statistics on the downlink channel information, obtain downlink statistical channel information, obtain uplink statistical channel information according to the downlink statistical channel information, and obtain precoding according to the uplink statistical channel information. Matrix; precoding the data by a precoding matrix; inserting an uplink sounding reference signal into the precoded data and transmitting.

The base station 302 is configured to detect and obtain uplink channel information by using a sounding reference signal or a demodulation reference signal, and perform CQI (Channel Quality Indicator) estimation according to the uplink channel information. There are a plurality of specific implementation manners for performing CQI estimation. For example, the base station 302 performs maximum ratio combining on the uplink channel information, and calculates an SINR (Signal to Interference plus Noise Ratio) on each subcarrier according to the combined uplink channel information. Ratio, and calculating CQI by exponential effective SINR mapping (EESM) mapping; maximum ratio combining means: adding multiple uplink channel information in the frequency domain and/or time domain by a preset weight and adding them respectively; or The base station 302 calculates a signal to interference and noise ratio (SINR) on each subcarrier according to the uplink channel information, and passes EESM (Expanential Effective SIR Mapping); SIR: Signal Interference Ratio, CQI is calculated; or, the base station selects a codeword from a preset codebook, and obtains equivalent channel information according to the selected codeword and uplink channel information, and calculates each sub-portion according to the equivalent channel information. The SINR on the carrier, and the CQI calculated by the EESM mapping. The base station 302 is further configured to estimate an uplink equivalent channel by demodulating the reference signal, and detect data on the uplink equivalent channel.

As shown in FIG. 4, the terminal 301 includes a channel estimation module 401, a statistics module 402, a conversion module 403, a precoding matrix module 404, a precoding module 405, an insertion module 406, and an interface module 407.

The channel estimation module 401 is configured to perform downlink channel estimation according to the downlink reference signal to obtain downlink channel information. For example, performing downlink channel estimation according to the downlink reference signal, obtaining a downlink channel estimation matrix, and obtaining a downlink channel correlation matrix or a downlink channel covariance matrix according to the downlink channel estimation matrix. That is, the downlink channel information is a downlink channel correlation matrix or a downlink channel covariance matrix. The downlink channel information may also be other information, such as a downlink channel estimation matrix, etc., which are not enumerated here.

The statistics module 402 is configured to perform statistics on the downlink channel information to obtain downlink statistical channel information. Since the downlink channel information is a downlink channel correlation matrix or a downlink channel covariance matrix, the statistics module 402 has multiple specific implementation manners, such as averaging multiple downlink channel correlation matrices in the frequency domain and/or the time domain, and obtaining an average. The downlink statistical channel correlation matrix; or, averages a plurality of downlink channel covariance matrices in the frequency domain and/or the time domain to obtain an averaged downlink statistical channel covariance matrix. Averaging a matrix means: averaging multiple elements at the same location in multiple matrices.

The converting module 403 is configured to obtain uplink statistical channel information according to downlink statistical channel information. The conversion module 403 has various specific implementation manners, for example, in a TDD (Time Division Duplex) and an FDD (Frequency Division Duplex) system, using the symmetry of the channel, the downlink statistical channel information is directly used as Uplink statistical channel information; or, in the FDD system, performing frequency band conversion on the downlink statistical channel information to obtain uplink statistical channel information. The frequency band conversion process includes: obtaining an uplink statistical channel correlation matrix according to the formula R„=T"R _d T, R _u represents an uplink statistical channel correlation matrix, R _d represents a downlink statistical channel correlation matrix, T represents a frequency band conversion matrix, and T represents T Conjugated transposition; T ( 0 ) = diag ( 1 , e ^o , ... ,

-j2nd^ ^DL ~ ^fvL (N wide l) sin( )

e ^/θ ), diag denotes a diagonal matrix, j denotes an imaginary part, d denotes an antenna spacing, f _fl denotes a downlink carrier frequency, f denotes an uplink carrier frequency, f _Q denotes a reference carrier frequency, denotes a number of transmitting antennas; or, R _u Indicates the uplink statistical channel covariance matrix, and R _d represents the downlink statistical channel covariance matrix.

The precoding matrix module 404 is configured to obtain a precoding matrix according to the uplink statistical channel information. The precoding matrix module 404 has multiple specific implementation manners. For example, because the uplink channel information is an uplink statistical channel correlation matrix or an uplink statistical channel covariance matrix, the eigenvalue decomposition of the uplink statistical channel correlation matrix is performed to obtain a maximum eigenvalue corresponding. An eigenvector, the eigenvector is a precoding matrix; or eigenvalue decomposition of the uplink statistical channel covariance matrix to obtain a eigenvector corresponding to the largest eigenvalue, the eigenvector being a precoding matrix; that is, the eigenvector V=eig ( R„), eig denotes a feature vector function, or as another way: select a codeword W from a preset CB (Code Book) according to the uplink statistical channel information as a precoding matrix, wherein each codeword They are all a matrix. In the implementation, the selected codeword W can maximize the capacity of the downlink, that is, W=argmax(C( )),

WeCB

C represents capacity. If the downlink channel information is a downlink channel estimation matrix, the uplink statistical channel estimation matrix may be further obtained, and the precoding matrix module 404 is further configured to perform singular value decomposition on the uplink statistical channel estimation matrix, or according to the uplink statistical channel estimation matrix from the preset A codeword W is selected as a precoding matrix in the codebook CB. In this embodiment, the transmission performance obtained by performing precoding by the uplink statistical channel correlation matrix or the uplink statistical channel covariance matrix is superior to the transmission performance obtained by performing precoding by the uplink statistical channel estimation matrix.

The precoding module 405 is used to precode the data through a precoding matrix. This data is obtained by modulation coding. Therefore, the terminal 301 further includes a modulation and coding module 408 for modulating and encoding data according to the CQI fed back by the base station 302.

The inserting module 406 is configured to insert an uplink sounding reference signal into the precoded data. number.

The interface module 407 is configured to transmit data including a sounding reference signal.

The base station 302 includes: a sounding module and an estimation module.

The detecting module is configured to detect and obtain uplink channel information by detecting the reference signal or demodulating the reference signal.

The estimation module is configured to perform channel quality indication CQI estimation according to the uplink channel information. The estimation module includes: a first estimating unit, configured to perform maximum ratio combining on the uplink channel information, and perform CQI estimation according to the combined uplink channel information; and a second estimating unit, configured to calculate, on the basis of the uplink channel information, each subcarrier Signal to interference and noise ratio SINR, and calculate CQI by exponential effective SINR mapping EESM mapping; third estimating unit, configured to select a codeword from a preset codebook, and obtain according to the selected codeword and uplink channel information, etc. The effective channel information, the SINR on each subcarrier is calculated based on the equivalent channel information, and the CQI is calculated by the EESM mapping.

The above is an introduction to the communication system and the terminal device 301. The following describes the processing procedure of the uplink data based on the same inventive concept. Since the principle of the processing of the uplink data is similar to that of the foregoing communication system and the terminal device, the implementation of the method can be referred to the implementation of the communication system and the terminal device, and the details are not described again.

Referring to FIG. 5, the implementation process of the primary processing method of the uplink data in this embodiment may be as follows: Step 501: The terminal 301 obtains a precoding matrix according to the uplink statistical channel information, and the uplink statistical channel information is obtained by the terminal to obtain statistics on the downlink channel information. The downlink statistical channel information is obtained according to the downlink statistical channel information.

Step 502: The terminal 301 precodes the data through a precoding matrix.

Step 503: The terminal 301 sends the pre-coded data.

The downlink channel information is a downlink channel correlation matrix or a downlink channel covariance matrix, and the other steps are also implemented in multiple manners. The implementation process is described in detail below through two embodiments.

Referring to FIG. 6, the flow of the uplink data processing method when the downlink channel information is the downlink channel correlation matrix in this embodiment is as follows:

Step 601: The terminal 301 performs channel estimation by using a downlink reference signal to obtain a downlink channel estimation. Matrix H. The downlink reference signal includes a downlink CRS (Common Reference Signal), a downlink DMRS (demodulation reference signal), or a channel state information reference signal (CSI-RS). Wait.

Step 602: The terminal 301 obtains a downlink channel correlation matrix according to the downlink channel estimation matrix H, and the downlink channel correlation matrix R=H'*H. H' represents the conjugate transpose of H.

Step 603: The terminal 301 averages multiple downlink channel correlation matrices in the frequency domain and/or the time domain to obtain a statistical downlink statistical channel correlation matrix R _rf . In the time domain, for example, all downlink channel correlation matrices in 2s are averaged, and 2s is a preset duration parameter value. In the frequency domain, multiple downlink channel correlation matrices are obtained according to multiple downlink reference signals.

Step 604: The terminal 301 obtains an uplink statistical channel correlation matrix R _u according to the downlink statistical channel correlation matrix R _rf . The terminal 301 can directly R _§ = R _d or band-convert R _rf in the FDD system to obtain R „.

Step 605: The terminal 301 performs eigenvalue decomposition on the uplink statistical channel correlation matrix R „, and further obtains the eigenvector V corresponding to the maximum eigenvalue, and determines that the eigenvector V is a precoding matrix.

Step 606: The terminal 301 modulates and encodes the data according to the CQI fed back by the base station, and inserts a demodulation reference signal into the modulated encoded data. This step is an independent operation with respect to steps 601-605, and there is no strict execution order.

Step 607: The terminal 301 pre-codes the data inserted into the demodulation reference signal according to the precoding matrix, and inserts an uplink sounding reference signal into the pre-coded data. In this step, instead of inserting an uplink sounding reference signal after each precoding, it may be selected according to actual needs.

Step 608: The base station 302 estimates the uplink equivalent channel by demodulating the reference signal, and detects the uplink data on the uplink equivalent channel. Since the precoding matrix determined according to the uplink statistical channel information is pre-coded in this embodiment, the base station 302 does not need to pre-decode the uplink data. Step 609: The base station 302 detects the obtained uplink channel matrix H _ie by sounding the reference signal, and performs CQI estimation according to the uplink channel matrix. For example, base station 302 calculates a signal to interference and noise ratio (SI R ) on each subcarrier based on the uplink channel matrix, ie

σ represents the power of the noise; the EESM map is used to calculate the CQI.

Referring to FIG. 7, the flow of the uplink data processing method when the downlink channel information is the downlink channel covariance matrix in this embodiment is as follows:

Step 701: The terminal 301 performs channel estimation by using a downlink reference signal to obtain a downlink channel estimation matrix H. The downlink reference signal includes a downlink CRS, a downlink DMRS, or a downlink CSI-RS.

Step 702: The terminal 301 obtains a downlink channel covariance matrix and a downlink channel correlation matrix according to the downlink channel estimation matrix H.

Step 703: The terminal 301 averages multiple downlink channel covariance matrices in the frequency domain and/or the time domain to obtain a downlink downlink statistical channel covariance matrix R _d . In the time domain, for example, all downlink channel covariance matrices in 2s are averaged, and 2s is a preset duration parameter value. In the frequency domain, multiple downlink channel covariance matrices are obtained according to multiple downlink reference signals.

Step 704: The terminal 301 obtains an uplink statistical channel covariance matrix R „ according to the downlink statistical channel covariance matrix R _rf . The terminal 301 may directly perform R „= R _rf or perform band conversion on the F1 system to obtain R „ Step 705: The terminal 301 selects a codeword W from the preset codebook CB as a precoding matrix according to the uplink statistical channel covariance matrix R. In practice, the codeword W can maximize the upstream capacity, ie W = arg max(C(^)), where C is the capacity.

WeCB

Step 706: The terminal 301 modulates and encodes the data according to the CQI fed back by the base station, and inserts the demodulation reference signal into the modulated encoded data. This step is an independent operation with respect to steps 701-705, without strict execution order.

Step 707: The terminal 301 pre-codes the data after inserting the demodulation reference signal according to the precoding matrix, and inserts an uplink sounding reference signal into the pre-coded data. Step 708: The base station 302 estimates an uplink equivalent channel by demodulating the reference signal, and detects uplink data on the uplink equivalent channel.

Step 709: The base station 302 detects the uplink channel matrix H _ie by demodulating the reference signal, and performs CQI estimation according to the uplink channel matrix. For example, the base station 302 selects a codeword W from the codebook CB, and finds an equivalent channel matrix according to the codeword W and the uplink channel matrix, and then calculates an SINR on each subcarrier according to the equivalent channel matrix H _e *W, and then utilizes The EESM map calculates the CQI. The base station 302 and the terminal 301 select the same codeword W according to their own selection rules.

The software for implementing the embodiments of the present invention can be stored in a storage medium such as a floppy disk, a hard disk, an optical disk, and a flash memory.

In the embodiment of the present invention, the uplink channel information is obtained by using the downlink channel information, and the precoding matrix is obtained according to the uplink channel information, and the uplink data is further precoded to implement the uplink closed loop transmit diversity, which may be compared with the existing transmit diversity mode. Better performance. Referring to the simulation effect diagram shown in FIG. 8, in the 2x2 line array, the speed is 30km/h, and the performance comparison of several transmission diversity modes can be seen. The two precoding methods in the embodiments of the present invention are based on the codebook. The precoding and non-codebook based precoding (ie precoding based on eigenvalue decomposition) are superior in performance to STBC coding, SFBC coding and low peak-to-average ratio SFBC coding. Moreover, in the embodiment of the present invention, when the uplink channel information is obtained according to the downlink channel information, multiple implementation manners are provided, which are suitable for the application of the TDD and the FDD system.

It is apparent that those skilled in the art can make various modifications and variations to the invention without departing from the spirit and scope of the invention. Therefore, it is intended that the present invention cover the modifications and variations of the invention as claimed.

Claims

Rights request

An uplink data processing method, comprising the steps of:

The terminal precodes the data through a precoding matrix;

The terminal transmits the precoded data.

2. The method according to claim 1, wherein the downlink channel information is a downlink channel correlation matrix or a downlink channel covariance matrix.

3. The method according to claim 2, wherein the step of the terminal to collect downlink channel information by using the downlink channel information comprises: the terminal averaging the plurality of downlink channel correlation matrices in the frequency domain and/or the time domain. , obtaining an averaged downlink statistical channel correlation matrix; or

The step of the terminal counting the downlink channel information and obtaining the downlink statistical channel information comprises: the terminal averaging the plurality of downlink channel covariance matrices in the frequency domain and/or the time domain to obtain an averaged downlink statistical channel covariance matrix.

The method according to claim 1, 2 or 3, wherein the step of obtaining, by the terminal, the uplink statistical channel information according to the downlink statistical channel information comprises: the terminal directly using the downlink statistical channel information as the uplink statistical channel information; or

The step of obtaining, by the terminal, the uplink statistical channel information according to the downlink statistical channel information includes: performing, by the terminal, frequency band conversion on the downlink statistical channel information, to obtain uplink statistical channel information.

The method according to claim 1, 2 or 3, wherein the step of obtaining, by the terminal, the precoding matrix according to the uplink statistical channel information comprises: performing eigenvalue decomposition on the uplink statistical channel correlation matrix by the terminal to obtain a maximum eigenvalue Corresponding feature vector, the feature vector is a precoding matrix; or

The step of the terminal obtaining the precoding matrix according to the uplink statistical channel information includes: the terminal performing eigenvalue decomposition on the uplink statistical channel covariance matrix to obtain a feature vector corresponding to the largest eigenvalue, The eigenvector is a precoding matrix; or

The step of the terminal obtaining the precoding matrix according to the uplink statistical channel information comprises: the terminal selecting a codeword from the preset codebook as the precoding matrix according to the uplink statistical channel information.

6. A terminal device, comprising:

a precoding module, configured to precode data through a precoding matrix;

An interface module, configured to send pre-coded data.

The device according to claim 6, wherein the precoding matrix module is further configured to perform statistics on the downlink channel correlation matrix or the downlink channel covariance matrix to obtain downlink statistical channel information.

8. The apparatus according to claim 7, wherein the precoding matrix module is further configured to average the plurality of downlink channel correlation matrices in the frequency domain and/or the time domain to obtain an averaged downlink statistical channel correlation matrix. Or, averaging multiple downlink channel covariance matrices in the frequency domain and/or the time domain to obtain an averaged downlink statistical channel covariance matrix.

The apparatus according to claim 6, 7 or 8, wherein the precoding matrix module is further configured to directly use the downlink statistical channel information as the uplink statistical channel information; or perform frequency band conversion on the downlink statistical channel information to obtain Upstream statistical channel information.

The apparatus according to claim 6, 7 or 8, wherein the precoding matrix module is further configured to perform eigenvalue decomposition on the uplink statistical channel correlation matrix to obtain a feature vector corresponding to the largest eigenvalue, the feature The vector is used as a precoding matrix; or, the eigenvalue decomposition is performed on the uplink statistical channel covariance matrix to obtain a eigenvector corresponding to the largest eigenvalue, and the eigenvector is used as a precoding matrix; or, according to the uplink statistical channel information, from the preset A codeword is selected as a precoding matrix in the codebook.