WO2009046626A1 - Procédé et appareil de détermination pour une information d'état de voie de liaison descendante et procédé et appareil de précodage - Google Patents

Procédé et appareil de détermination pour une information d'état de voie de liaison descendante et procédé et appareil de précodage Download PDF

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Publication number
WO2009046626A1
WO2009046626A1 PCT/CN2008/001666 CN2008001666W WO2009046626A1 WO 2009046626 A1 WO2009046626 A1 WO 2009046626A1 CN 2008001666 W CN2008001666 W CN 2008001666W WO 2009046626 A1 WO2009046626 A1 WO 2009046626A1
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WO
WIPO (PCT)
Prior art keywords
channel
state information
uplink
downlink
determining
Prior art date
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PCT/CN2008/001666
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English (en)
Chinese (zh)
Inventor
Yunhui Liu
Xiaolin Zhang
Xiang Li
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Lenovo (Beijing) Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by Lenovo (Beijing) Limited filed Critical Lenovo (Beijing) Limited
Publication of WO2009046626A1 publication Critical patent/WO2009046626A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/0224—Channel estimation using sounding signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/024—Channel estimation channel estimation algorithms
    • H04L25/0242—Channel estimation channel estimation algorithms using matrix methods
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
    • H04L25/03006—Arrangements for removing intersymbol interference
    • H04L25/03343—Arrangements at the transmitter end

Definitions

  • the present invention relates to downlink channel state information determination and application techniques in a Time Division Duplex (TDD) system, and more particularly to a method and apparatus for determining downlink channel state information in a time division duplex system, and a downlink channel precoding method and apparatus.
  • TDD Time Division Duplex
  • LTE Long Term Evolution
  • MIMO multiple input multiple output
  • the uplink channel estimate can be precoded as downlink channel information using the reciprocal properties of the channel during the channel coherence time.
  • the uplink channel estimation is relatively easy to implement.
  • the base station side can complete the estimation of the uplink channel according to the pilot signal. It is assumed that the estimated uplink channel is H u . According to the reciprocity principle, the transposition of H u is 1! 'anni is the downlink channel, the base station The side transmitter directly considers H'u as the downlink channel estimation for corresponding precoding.
  • the reciprocal attribute of the channel in the TDD system may be destroyed, for example, when the user terminal UE is in a high-speed moving state, due to the Doppler The expansion or delay spread, the reciprocal property of the channel is destroyed; or when the uplink and downlink slot spacing is greater than the coherence time of the channel, the reciprocal properties of the channel are also destroyed.
  • the channel reciprocal property can only be applied to the wireless between the antennas.
  • the channel is measured and estimated at the baseband processing unit. Different transmit and receive radio links are also included in the forward or reverse link, and the link has different transmission characteristics. There will be a deviation between the estimated uplink channel and the actual downlink channel.
  • the number of time slots will be less than the number of downlink time slots, resulting in a further increase in the uplink and downlink time slot intervals, which also leads to the destruction of the channel reciprocal properties.
  • the delay time of signal processing, etc. will affect the transmitter to obtain precoding transmission. Accurate channel information. Based on the above reasons, based on the channel reciprocal attribute Shooting performance is bound to decline.
  • the existing scheme processes the estimated channel in a calibrated manner, and calibrates the channel offset caused by different uplink and downlink RF links, and the base station performs precoding and transmitting processing using the calibrated channel information.
  • this solution only solves the problem of channel reciprocal attribute destruction caused by different uplink and downlink RF links.
  • Another solution in the prior art is to feed back part of the channel information to the transmitter through the feedback channel, and then combine the downlink channel information obtained according to the channel reciprocal attribute to jointly determine the transmission channel information.
  • the disadvantages are: A dedicated feedback channel is required, and feedback information reduces spectral efficiency.
  • the main object of the present invention is to provide a method and apparatus for determining downlink channel state information in a time division duplex system, and a downlink channel precoding method and apparatus, which can provide more accurate downlink channel state information and obtain better information. Precoding effect.
  • a method for determining downlink channel state information in a time division 3 ⁇ 4 worker system includes:
  • the pilot signal to estimate the uplink channel information to calculate the instantaneous channel state information H f, and based on long term channel statistics estimates the downlink channel information H e, and determining H e, the weighting factor between H f ⁇ , according H e, H f And ⁇ determines the line channel state information H d .
  • determining the weight coefficient ⁇ between H e and H f includes:
  • the correlation coefficient between the channels ⁇ , ( ⁇ + ⁇ ), £ ⁇ ⁇ is the variance calculation, and is the estimation error of the uplink channel.
  • the calculating the instantaneous channel state information H f includes:
  • the downlink channel H e is estimated according to the long-term channel statistical characteristics, including: H ( , t estimated
  • H e H m + H 2 , where I ⁇ N ⁇ N, the complex Gaussian random matrix of the dimension, N, is the number of antennas at the transmitting end.
  • a precoding method for determining downlink channel state information based on the foregoing method including:
  • Downstream channel precoding is performed by using the downlink channel state information determined by the foregoing method.
  • An apparatus for determining downlink channel state information in a time division duplex system comprising: an uplink channel estimating unit, configured to estimate an uplink channel according to a pilot signal;
  • An instantaneous channel state information calculation unit configured to calculate instantaneous channel state information Hf of the estimated uplink channel ; a long-term channel statistical characteristic downlink channel estimation unit, configured to estimate a downlink channel according to long-term channel statistical characteristics
  • a weight coefficient determining unit for determining a weight coefficient ⁇ between H e and H f ;
  • Downlink channel state information calculation means for determining a downlink channel state information according H d H e, H f and ⁇ . Wherein said downlink channel state information calculation unit determines H d, in particular - to calculate H e (1 - a), H f with the product of ⁇ , is the sum of the product of two H d. ⁇
  • the weight coefficient determining unit includes:
  • a time point channel extracting module configured to extract an estimated channel of a first uplink time slot start time in the data frame and an estimated channel of an intermediate time of all uplink time slots;
  • a channel correlation coefficient calculation module configured to calculate a correlation coefficient between the estimated channel at an intermediate time of each uplink time slot and an estimated channel at a start time of the first uplink time slot, in the order of PP 2 ... p p ;
  • the channel correlation coefficient calculation module includes:
  • the inter-channel variance calculation sub-module is configured to calculate the channel H at the uplink time t, (0 and the variance between the channels H, (t + At) at the uplink time t+ ⁇ H, (H, (t + At) ⁇ ;
  • An uplink channel estimation error calculation sub-module configured to calculate an estimation error of the uplink channel;
  • a channel correlation coefficient calculation sub-module configured to calculate a channel H at the uplink time t, (t), and a channel ⁇ at an uplink time t+At, ( +
  • the correlation coefficient P(,, + ⁇ ,) between ⁇ 0 is: £ ⁇ , ( ) ⁇ , ( ⁇ + ⁇ ⁇ / [ ], wherein the instantaneous channel state information calculation unit calculates H f , include:
  • H e H m +H 2 , where H w is xN, the complex Gaussian random matrix of the dimension, N, is the number of antennas at the transmitting end.
  • a precoding apparatus based on the downlink channel state information determined by the foregoing apparatus includes:
  • a channel precoding unit configured to perform downlink channel precoding by using downlink channel state information determined by the foregoing apparatus.
  • the method and apparatus for determining the downlink channel state information of the present invention determine the downlink channel H e according to the instantaneous channel state information H f and the long-term channel statistical characteristic. And the weight coefficient a between them to determine the downlink channel state information, so that when the correlation coefficient between the channels becomes smaller, that is, when the slot interval is close to or larger than the coherence time of the channel, the downlink channel estimation is more inclined to use the long-term channel statistical characteristics.
  • estimating channel information i.e.
  • FIG. 1 is a schematic structural diagram of a device for determining downlink channel state information in a time division duplex system according to the present invention
  • FIG. 2 is a schematic structural diagram of a weight coefficient determining unit according to the present invention
  • FIG. 3 is a schematic structural diagram of a channel correlation coefficient calculation module in FIG. 2;
  • FIG. 4 is a schematic structural diagram of a TDD frame in an LTE system
  • FIG. 5 is a schematic diagram of a precoding application of a device for determining downlink channel state information in a time division duplex system according to the present invention
  • the present invention utilizes the reciprocal characteristics of the TDD system channel, and can determine the downlink channel according to the estimated uplink channel, which is very fast and convenient, and the downlink channel is the information necessary for precoding.
  • the reciprocal characteristics of the channel are easily destroyed, which will inevitably lead to inaccurate downlink channel information, thus affecting the effect of precoding.
  • the present invention is by determining the instantaneous channel state information H f, the weight coefficient ⁇ is determined according to the downlink channel state information weights therebetween estimate the long-term channel statistics of the downlink channel, and H e.
  • the downlink channel estimation is more inclined to use the channel information estimated by the long-term channel statistical characteristics, that is, the slow-changing component of the channel; downlink channel estimation tend to instantaneous channel state information H f channel estimated, i.e., full use of the properties of reciprocity of uplink and downlink channels.
  • the downlink channel state information determined by the present invention is more accurate, and the precoding technology based on the downlink channel state information can improve the transmission performance of the system.
  • the apparatus for determining downlink channel state information in a time division duplex system of the present invention includes an uplink channel estimating unit 10, The instantaneous channel state information calculating unit 11, the long-term channel statistical characteristic downlink channel estimating unit 12, the weighting coefficient determining unit 13, and the downlink channel state information calculating unit 14, wherein the uplink channel estimating unit 10 is configured to estimate the uplink channel according to the pilot signal.
  • the channel estimation method adopted by the uplink channel estimating unit 10 is In a more common manner in the field, the base station side determines the channel information according to the received current signal of the known pilot signal.
  • N is a noise signal, which is negligible because of the small power; the channel H for transmitting the pilot signal can be calculated by S2/S1. According to the correlation of the channel, the channel used for the data transmitted together with the pilot signal is also regarded as H. .
  • the instantaneous channel state information calculation unit 11 is configured to calculate the instantaneous channel state information H f of the estimated uplink channel.
  • the pilot signal estimated uplink channel H u, H f H ⁇ , wherein! ⁇ Yes! Transpose of ⁇ .
  • For the uplink channel estimation reference may be made to the related description of the foregoing uplink channel estimation unit 10.
  • M is the number of uplink channel samples
  • H: is the uplink time t J estimates the transposition of channel H
  • N is the number of antennas of the mobile terminal
  • ()* is the conjugate calculation
  • H w is a randomly generated parameter, and the general digital signal processor (DSP) with channel state information calculation has the generated 1 ⁇ Function
  • N is the number of antennas at the receiving end, that is, the user terminal, and N is the number of antennas at the transmitting end.
  • the weight coefficient determination unit 13 is for determining the weight coefficient ⁇ between H e and H f .
  • the weight coefficient ⁇ of the present invention is a coefficient factor related to the channel coherence time and the terminal motion speed, that is, ⁇ ⁇ / ⁇ , ⁇ ⁇ ), where ' r c £ ⁇ /l is the coherence time of the channel, and T d is Delay extended, /() is a function.
  • /() is a function.
  • the downlink channel state information calculation unit 14 performs calculation based on the calculation results of the instantaneous channel state information calculation unit 11, the long-term channel statistical characteristic downlink channel estimation unit 12, and the weight coefficient determination unit 13, and is a pure calculation unit.
  • weight coefficients may be corrected before ⁇ calculated by the above formula.
  • the square root of a and the power are positive, and are not limited to integers.
  • the weight coefficient determining unit 13 of the present invention includes a time point channel extracting module 130, a channel correlation coefficient calculating module 131, and a data frame time slot judgment and weight.
  • 3 is a schematic diagram of a structure of a TDD frame in an LTE system. As shown in FIG.
  • a TDD frame includes seven TS slots, which are TS0 to TS6, where TS0 is a downlink slot, TS1 is an uplink slot, and TS2 to TS6 are available. Dynamically adjusted to uplink or downlink time slots as needed, TS1 to TS3 shown in the figure are uplink time slots, and TS4 to TS6 are downlink time slots.
  • the UpPTS is an uplink pilot time slot
  • the DwPTS is a downlink pilot time slot
  • each time slot has a guard interval.
  • the length of each time slot is shown by the number indicated in the figure, and the unit is ⁇ 3.
  • the first uplink time slot start time is 950 ⁇ 8 .
  • the middle time of each upstream time slot is at the right end of the length shown by ⁇ 2 and ⁇ 3 in the figure.
  • the time point channel extraction module 130 determines the channel information at the time point.
  • the channel correlation coefficient calculation module 131 is configured to calculate a correlation coefficient between the estimated channel at the intermediate time of each uplink time slot and the estimated channel at the start time of the first uplink time slot, in the order of ⁇ ⁇ 2 ... ⁇ ⁇ ⁇ ⁇ 2 , ⁇ 3 in the figure.
  • the channel correlation coefficient calculation module 131 includes an inter-channel variance calculation sub-module 1310, an uplink channel estimation error calculation sub-module 1311, and a channel correlation coefficient calculator.
  • Module 1312 wherein the inter-channel variance calculation sub-module 1310 is configured to calculate the channel H at the uplink time t, (0 and the channel ⁇ at the uplink time t+At, the variance between ( ⁇ + ⁇ /) ⁇ H, (0H, ( The uplink channel estimation error calculation sub-module 1311 is configured to calculate an estimation error of the uplink channel 0 6 2 .
  • the channel correlation coefficient calculation sub-module 1312 is configured to calculate the channel ⁇ at the uplink time t, ( ⁇ ) and the uplink time t+At At channel ⁇ , (the correlation coefficient ⁇ (,, , ⁇ , ) between ⁇ + ⁇ 0 is: ⁇ H,(0H,(t + A0 ⁇ / [ ⁇ ⁇ 2 ].
  • ⁇ ⁇ is seeking
  • the variance calculation which is the estimated error of the uplink channel, is related to the channel estimation error used. For example, if the transmitted training symbol is an orthogonal training symbol, the variance of the minimum mean square error (MMSE) channel estimate is:
  • R r is the training symbol transmission power
  • L is the number of training symbols in the transmitted pilot
  • N is the number of antennas at the receiving end
  • 5 is a schematic diagram of precoding application of a device for determining downlink channel state information in a time division duplex system according to the present invention. As shown in FIG. 5, the base station side performs uplink and downlink data processing on a TDD channel, and the base station receives uplink according to the uplink.
  • the signal performs channel estimation processing, that is, the processing method of the determining apparatus for downlink channel state information of the present invention determines the downlink channel state information, and transmits the determined downlink channel state information to the precoding processing unit, and the precoding processing unit receives the
  • the downlink channel state information is selected to encode a corresponding coding strategy to be transmitted and transmitted through the TDD channel. Since the downlink channel state information is more accurate, the transmission performance of the system can be improved.
  • FIG. 6 is a flowchart of a method for determining downlink channel state information in a time division duplex system according to the present invention. As shown in FIG. 6, the method for determining downlink channel state information in the time division duplex system of the present invention includes:
  • Step 501 Estimate the uplink channel according to the pilot signal.
  • the uplink channel estimation method is a well-known technique and will not be described here.
  • H e For a complex Gaussian random matrix of > ⁇ ⁇ dimension, its elements obey independent and identical distribution, with zero mean and unit variance; H w is a randomly generated parameter, and the general DSP with channel state information calculation has the function of generating H w N is the number of antennas at the receiving end, ie, the user terminal, and N is the number of antennas at the transmitting end.
  • Step 503 Determine the weight coefficient ⁇ between H e and H f .
  • the weight coefficient ⁇ For the determination of the weight coefficient ⁇ , reference may be made to the description of the apparatus for determining the downlink channel state information in the time division duplex system of the present invention, and details are not described herein again.
  • steps 502 and 503 can be interchanged.
  • Step 504 Calculate the downlink channel state information H d according to the H e , H f , and ⁇ calculated in the foregoing steps, as follows:
  • weight coefficients may be corrected before a calculation according to the above formula.
  • the root of the root of a or a number of powers is corrected, such as the square root of a, the downlink channel state information Or correct by the square of a, downlink channel status information
  • H d (l - a 2 )H e + a 2 H f .
  • the root and power of a are positive, and are not limited to integers.
  • the precoding method in the time division duplex system of the present invention will be described below in conjunction with the above determination method.
  • the precoding method of the present invention preprocesses the data to be transmitted by using the downlink channel state information determined by the above determining method, and carries the precoded data on the TDD channel for transmission.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

La présente invention concerne un procédé de détermination pour une information d'état de voie de liaison descendante dans un système TDD permettant de résoudre le problème de non détermination précise courante de la voie de liaison descendante. Le procédé comprend : l'estimation de l'information de voie de liaison montante selon les symboles pilotes ; le calcul de l'information d'état transitoire de voie Hf; l'estimation de l'information de voie de liaison descendante He selon les caractères statistiques de voie sur une longue durée ; la détermination d'un facteur de pondération α entre Hf et He; la détermination de l'information d'état de voie de liaison descendante en fonction de He, α and Hf. L'invention concerne également un appareil mettant en œuvre le procédé de détermination et un procédé et un appareil de précodage utilisant le procédé et l'appareil de détermination. La présente invention réduit la détérioration de performance de précodage provoquée par la destruction de la condition réciproque de voies et améliore la stabilité du système de transmission en liaison descendante.
PCT/CN2008/001666 2007-09-27 2008-09-27 Procédé et appareil de détermination pour une information d'état de voie de liaison descendante et procédé et appareil de précodage WO2009046626A1 (fr)

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CN2007101752208A CN101400117B (zh) 2007-09-27 2007-09-27 下行信道状态信息确定方法与装置及预编码方法与装置
CN200710175220.8 2007-09-27

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CN102013904A (zh) * 2009-09-27 2011-04-13 大唐移动通信设备有限公司 一种上行数据处理方法及***
US20110103493A1 (en) * 2009-11-02 2011-05-05 Futurewei Technologies, Inc. System and Method for Wireless Communications with Adaptive Codebooks
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CN103312440A (zh) * 2012-03-13 2013-09-18 中兴通讯股份有限公司 一种基于信道状态信息反馈的数据发射方法及装置
CN104702543B (zh) * 2013-12-04 2018-05-29 华为技术有限公司 预编码方法及装置
CN106160803A (zh) * 2015-03-30 2016-11-23 北京信威通信技术股份有限公司 基于信道互易性获取下行信道信息的方法、装置和***
CN107979551B (zh) * 2016-10-25 2022-04-15 中兴通讯股份有限公司 一种信道误差获取方法及装置
CN108282250B (zh) * 2017-01-06 2021-03-26 维沃移动通信有限公司 一种下行信道状态信息的测量方法、基站及终端
CN108494445B (zh) * 2018-01-17 2019-10-01 江苏大学 大规模mimo中基于上行信道信息辅助的下行信道估计方法

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CN101400117A (zh) 2009-04-01

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