WO2008049352A1 - Procédé et dispositif pour stc et décodage de stc - Google Patents
Procédé et dispositif pour stc et décodage de stc Download PDFInfo
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- WO2008049352A1 WO2008049352A1 PCT/CN2007/070403 CN2007070403W WO2008049352A1 WO 2008049352 A1 WO2008049352 A1 WO 2008049352A1 CN 2007070403 W CN2007070403 W CN 2007070403W WO 2008049352 A1 WO2008049352 A1 WO 2008049352A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/02—Arrangements for detecting or preventing errors in the information received by diversity reception
- H04L1/06—Arrangements for detecting or preventing errors in the information received by diversity reception using space diversity
- H04L1/0618—Space-time coding
- H04L1/0637—Properties of the code
- H04L1/0668—Orthogonal systems, e.g. using Alamouti codes
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/02—Arrangements for detecting or preventing errors in the information received by diversity reception
- H04L1/06—Arrangements for detecting or preventing errors in the information received by diversity reception using space diversity
- H04L1/0618—Space-time coding
- H04L1/0631—Receiver arrangements
Definitions
- the present invention relates to the field of wireless communication technologies, and in particular, to a space time codec method and apparatus. Background of the invention
- MIMO multi-antenna system
- STBC space-time block coding
- the transmission rate of the system is low.
- the transmit signal matrix of the algorithm is:
- antenna 1 and antenna 2 of the base station respectively transmit and transmit to the mobile terminal, at which time, the received signal of the mobile terminal is:
- antenna 1 and antenna 2 of the base station respectively transmit - and to the mobile terminal, at which time, the received signal of the mobile terminal is:
- the mobile terminal can use the maximum likelihood criterion to perform detection detection on the two original signals and the 3 ⁇ 4 transmitted by the base station.
- the transmitted signal is transmitted, and * indicates the conjugate operation.
- the four transmit antenna systems are calculated for the detected 'J signal: ⁇ ⁇ — ⁇ ⁇ ⁇ h 2 r 2 + hr + h 4 r 4 + r 5 + h 2 r 6 + hr 7 + h 4 r s ;
- x 2 h 2 r x — r 2 h 4 r 3 + h 3 r 4 + h 2 r 5 ⁇ r k h 4 r 7 + h 3 r s ;
- x 3 ⁇ ⁇ + h:r 2 h*r 3 h*r 4 + h 3 r 5 * + h 4 r: h 2 r ⁇ ;
- x 4 -h ⁇ hr 2 + hr 3 h ⁇ r 4 h 4 rh 3 r: + h 2 r; It is not difficult to see that when the transmitted signal to be transmitted is a complex signal, if the number of transmitting antennas is more than two, the equivalent transmission rate of the system can only reach half of the transmission rate of the single antenna system (SISO) system, and the MIMO system is reduced. Equivalent transmission rate.
- Embodiments of the present invention provide a space-time codec method and apparatus in a multi-antenna wireless communication system, which can reduce a bit error rate of the system.
- a space time coding method including:
- Signal transmission is performed according to the transmission signal matrix.
- a space time decoding method comprising:
- the transmit signal matrix corresponding to the received signal has orthogonality, and weighting and combining the received signal according to channel state information;
- the weighted combined received signal is detected, and an estimated value of the transmitted signal corresponding to the received signal is obtained based on the channel state information.
- a space time coding device comprising:
- An orthogonal matrix construction module configured to generate an orthogonal matrix according to a transmit signal to be transmitted;
- a coefficient matrix determining module configured to generate a coefficient matrix corresponding to the orthogonal matrix according to channel state information;
- a transmit signal matrix forming module for using the coefficient matrix to the orthogonal matrix
- Each element in the weight is weighted to generate a matrix of transmitted signals
- the signal transmitting module transmits a signal through the transmitting antenna according to the transmission signal matrix.
- a space time decoding device comprising:
- a receiving signal combining module configured to acquire a received signal, where the transmitted signal matrix corresponding to the received signal has orthogonality, and the received signal is weighted and combined;
- the signal detection decision module is configured to detect the weighted combined received signal, and obtain an estimated value of the transmitted signal corresponding to the received signal according to the channel state information.
- the channel state information acquired by the transmitting end is used for space-time coding of the transmitted signal to be transmitted, which reduces the error rate of the system and improves the error performance of the system.
- the embodiment of the present invention uses the channel state information acquired by the transmitting end to perform space-time coding on the transmitted signal to be transmitted, thereby avoiding the conjugate operation of the transmitted signal to be transmitted, when the transmitted signal to be transmitted is two or more.
- the transmission rate of the system is significantly improved.
- FIG. 1 is a schematic structural view of a conventional two-antenna STBC system
- FIG. 2 is a flowchart of a method for encoding and decoding in a hollow time according to an embodiment of the present invention
- FIG. 3 is a schematic diagram showing a simulation result of a bit error rate applied to two transmit antenna systems according to an embodiment of the present invention
- FIG. 4 is a schematic diagram showing a simulation result of a bit error rate applied to a four-transmit antenna system according to an embodiment of the present invention
- FIG. 5 is a schematic structural diagram of a space-time codec device according to an embodiment of the present invention. Mode for carrying out the invention
- the space-time coding technology provided by the embodiment of the present invention utilizes channel state information known by the transmitting end to perform space-time coding on the information symbols to be transmitted, which not only improves the BER performance of the system, but also has a large number of transmitting antennas set in the system. In two cases, if the input signal of the system is a complex signal, the embodiment of the present invention can also increase the equivalent transmission rate of the system.
- the equivalent transmission rate is equal to the transmission rate of the SISO (Single Input Single Output) system regardless of the number of transmitting antennas set by the system.
- SISO Single Input Single Output
- FIG. 2 is a flowchart showing an embodiment of a method for encoding and decoding a space-time code according to an embodiment of the present invention.
- a multi-antenna wireless communication system is provided with M transmitting antennas and one receiving antenna, wherein
- M is an integer greater than 2, such as 2, 3, 4...
- the space-time coding and decoding process in the embodiment of the present invention specifically includes the following steps.
- Step 201 Generate an orthogonal matrix X of ⁇ ⁇ ⁇ according to the M transmit signals to be transmitted.
- an orthogonal matrix is generated according to one transmit signal to be transmitted, wherein the first row of the orthogonal matrix is one transmit signal to be transmitted; ⁇ , ⁇ 2 ⁇ ⁇ , and the remaining rows It consists of a different transmission sequence of the transmitted signals to be transmitted or the opposite of the transmitted signals to be transmitted, that is, the orthogonal matrix of ⁇ ⁇ ⁇ is composed of ⁇ , ⁇ 2 , ... ⁇ ⁇ .
- Step 202 Calculate a coefficient corresponding to each element in the transmit signal matrix according to the channel state information acquired by the transmitting end, and generate a coefficient matrix.
- the coefficient matrix is:
- the above matrices all satisfy the principle of maximum ratio combining.
- Step 203 Multiplying the orthogonal matrix X by the coefficient matrix, multiplying each element in the orthogonal matrix by an element in the corresponding coefficient matrix to generate a transmission signal matrix.
- the transmit signal matrix is:
- the rows in the transmit signal matrix correspond to the signals transmitted by the M transmit antennas at the same time, and the columns in the transmit signal matrix correspond to the signals transmitted by the same transmit antenna at the adjacent M moments.
- Step 204 Perform signal transmission according to the transmit signal matrix.
- the M transmit antennas respectively transmit signals in the transmit signal matrix to the wireless channel at M adjacent moments.
- the signals transmitted on different transmit antennas sequentially correspond to different elements in the rows in the transmit signal matrix; the signals transmitted by the same transmit antenna at adjacent moments sequentially correspond to the elements in the columns of the transmit signal matrix.
- the transmitted transmission signals may be grouped in advance to form a signal group to be transmitted, and then a space time coding operation is performed for each signal group to be transmitted.
- the receiving end After receiving the transmitted signal, the receiving end performs the following steps.
- Step 205 Acquire a received signal, and perform weighted combining on the received signals of the M adjacent moments according to the channel state information known by the receiving end and the orthogonality of the transmitted signal matrix.
- the weighting coefficients of the received signal may be calculated according to the channel state information using the principle of maximum ratio combining, and then the weighted coefficients and the orthogonality of the transmitted signal matrix are used to weight combine the received signals.
- Step 206 Perform detection detection on the weighted and combined received signals respectively, and obtain and An estimated value of the transmitted signal corresponding to the received signal.
- the receiving end simultaneously receives the training sequence from the transmitting end, and is used for estimating the channel state information, and feeding back the channel state information to the transmitting end.
- Embodiment 1 The system sets two transmitting antennas, and the receiving end is a single antenna mobile terminal. According to the transmit signal matrix in the embodiment shown in FIG. 2, when the value of M is 2, the transmit signal matrix in the two transmit antenna systems is as follows:
- the two elements of each row in the transmit signal matrix respectively correspond to the signals transmitted on the two transmit antennas at the time corresponding to the row, and the two elements of each column in the transmit signal matrix respectively correspond to the corresponding ones of the columns.
- the signal transmitted by the transmitting antenna at two adjacent moments.
- the transmitting antenna 1 and the transmitting antenna 2 are transmitted to the mobile terminal.
- the signals are ' and + ⁇ h respectively
- the receiving signal of the mobile terminal is among them, /! And mobile end
- the signal received by the terminal at time 2 and the additive Gaussian white noise are combined.
- the received signals are weighted and combined to obtain a signal and 2 respectively
- the mobile terminal can use the maximum likelihood criterion pair and the detection decision respectively to obtain the estimated values of the two transmitted signals from the transmitting antenna.
- the broken line indicates the bit error rate performance of the existing STBC algorithm in the two transmit antenna systems.
- the lines represent the bit error rate performance of the two transmit antenna systems in accordance with an embodiment of the present invention.
- the space-time coding method provided by the embodiment of the present invention has a signal-to-noise ratio gain greater than that of the conventional STBC algorithm, that is, the same bit error rate.
- the embodiment of the present invention saves the transmission power greater than ldB compared to the STBC algorithm; under the condition that the transmission power is the same, the embodiment of the present invention The method provided has a lower bit error rate.
- Embodiment 2 The system sets four transmitting antennas, and the receiving end is a single antenna mobile terminal. According to the transmit signal matrix in the embodiment shown in Fig. 2, when the value of M is 4, the transmit signal matrix in the four transmit antenna system is as follows:
- the four elements of each row in the transmit signal matrix respectively correspond to the signals transmitted on the four transmit antennas at the time corresponding to the row, and the four elements of each column in the transmit signal matrix respectively correspond to the transmit antennas corresponding to the column. Signals transmitted at four adjacent moments.
- the received signals of the mobile terminal at four adjacent moments are as follows:
- r ⁇ , r 2 , r 3 , r 4 and / ⁇ , " 2 , n 3 , " 4 respectively represent the signal received by the mobile terminal at time 1, time 2, time 4 and the additive Gaussian White Noise.
- the received signals are weighted and combined to obtain a signal, ⁇ 2 . ⁇ 3
- the mobile terminal can use the maximum likelihood criterion to perform a decision on _3 ⁇ 4, _3 ⁇ 4, and respectively, to obtain an estimate of the four transmitted signals from the transmit antenna.
- the broken line indicates the bit error rate performance of the existing STBC algorithm in the four-transmit antenna system.
- the line represents the bit error rate performance of the embodiment of the present invention in a four-transmit antenna system.
- the space-time coding scheme provided by the embodiment of the present invention has a signal-to-noise ratio gain of about 2 dB compared with the conventional STBC algorithm.
- the embodiment of the present invention saves about 2 dB of transmit power compared to the STBC algorithm, and the method provided by the embodiment of the present invention has a lower error under the condition that the transmit power is the same. Code rate.
- Embodiment 3 The system sets eight transmit antennas, and the receive end is a single antenna mobile terminal.
- the eight elements of each row in the transmit signal matrix respectively correspond to the signals transmitted on the eight transmit antennas at the time corresponding to the row, and the eight elements of each column in the transmit signal matrix respectively correspond to the corresponding transmit antennas in the column.
- the received signals of the mobile terminal at eight times and the estimated values of the eight transmitted signals obtained by the mobile terminal from the transmitting antenna can be based on the previously described two transmit antenna systems and four transmit antennas.
- the processing method of the system is analogously obtained, so it will not be described again.
- the space-time codec method in the embodiment of the present invention improves the error performance of the system, and the bit error rate of the system can be reduced regardless of whether the transmitted signal to be transmitted is a complex signal or a real signal.
- the space-time codec method in the embodiment of the present invention avoids the conjugate operation of the transmitted signal to be transmitted, and when the transmitted signal to be transmitted is a complex signal, the embodiment of the present invention can significantly improve the system equivalent. Transmission efficiency.
- the present invention further provides a space-time codec device in a multi-antenna wireless communication system based on the above-described multi-antenna wireless communication system hollow time codec method.
- FIG. 5 shows the structure of a space-time codec device according to an embodiment of the present invention, which device includes a space-time coding device, that is, a transmitting device and a space-time decoding device, that is, a receiving device.
- the space time coding apparatus includes:
- An orthogonal matrix construction module is configured to generate an orthogonal matrix according to a transmission signal to be transmitted.
- a coefficient matrix determining module configured to generate a coefficient matrix corresponding to the orthogonal matrix according to the channel state information.
- a transmit signal matrix forming module is configured to weight each element in the orthogonal matrix by a coefficient matrix to generate a transmit signal matrix.
- the signal transmitting module transmits signals through the transmitting antenna according to the transmitted signal matrix.
- the orthogonal matrix construction module further includes:
- a signal grouping unit to be transmitted configured to group the transmitted signals to be transmitted according to the number of transmitting antennas in the system.
- An orthogonal matrix generating unit is configured to generate an orthogonal matrix according to the transmitted signal to be transmitted after the grouping, where the first row element of the orthogonal matrix is a transmitting signal to be transmitted, and the remaining rows are the transmitting signal to be transmitted or the transmitting signal to be transmitted.
- the inverse of the number consists of different sequential arrangements.
- the coefficient matrix determination module further includes:
- the channel state information acquiring unit is configured to receive channel state information.
- the coefficient matrix calculation unit is configured to generate a coefficient matrix according to the channel state information.
- the coefficient matrix calculation unit generates a coefficient matrix according to the formula described below,
- the space-time decoding device includes:
- the receiving signal combining module is configured to obtain a received signal, where the transmit signal matrix corresponding to the received signal has orthogonality, and the received signal is weighted and combined.
- the signal detection decision module is configured to detect the received signal after the decision weighted combination, and obtain an estimated value of the transmitted signal corresponding to the received signal according to the channel state information.
- the channel state information estimating module is configured to estimate channel state information, and feed back channel state information to the transmitting end.
- the space time decoding device further includes:
- a weighting coefficient calculation module configured to calculate a weighting coefficient of the received signal according to the channel state information.
- the received signal combining module is further configured to perform weighted combining on the received signals according to the weighting coefficients.
- the channel state information acquired by the transmitting end is used for space-time coding of the transmitted signal to be transmitted, which reduces the bit error rate of the system and improves the error performance of the system.
- the embodiment of the present invention uses the channel state information acquired by the transmitting end to perform space-time coding on the transmitted signal to be transmitted, thereby avoiding the conjugate operation of the transmitted signal to be transmitted, when the transmitted signal to be transmitted is two or more.
- the embodiment of the present invention can significantly improve the equivalent transmission efficiency of the system.
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Description
一种空时编解码方法及装置 技术领域
本发明涉及无线通信技术领域,尤其涉及一种空时编解码方法和 装置。 发明背景
随着无线通信技术的发展,对无线通信系统的通信质量和传输速 率提出了更高的要求。 在无线通信系统中, 时间和频率资源有限, 因 此产生了多天线系统 ( MIMO, Multiple Input Multiple Output ) , 其 具有优越的信道容量性能, 从而受到广泛的关注。
在 MIMO系统中, 通常采用分集技术实现更好的信号传输质量。 但是, 由于移动终端的体积的受到限制, 没有足够的空间设置多个天 线以保证通信信道的独立性, 使得下行信道中无法实现接收分集。 由 于基站具有多天线处理能力, 在多天线无线通信系统中, 通常由空时 编码技术实现发射分集。
目前, STBC (空时分块编码) 以其较低的实现复杂度, 成为实 现发射分集的主流技术。
但是, 使用现有的 STBC算法时, 系统的误码率仍然较高, 导致 系统的接收性能较差, 限制了多天线无线通信系统的发展。
另外, 当系统中待传输的发射信号是两个或两个以上的复数时, 系统的传输速率较低。
以两天线的 STBC为例, 该算法的发射信号矩阵为:
χι), 其中, ^和 ^分别表示基站两个待传输的发射信号,
*表示共轭运算。
该算法的系统结构如图 1所示, 下面对该算法的具体实现进行说 明。
在时刻 1 , 基站的天线 1和天线 2分别向移动终端发射 和 ·¾ , 此 时, 移动终端的接收信号为:
在时刻 2, 基站的天线 1和天线 2分别向移动终端发射- 和 , 此 时, 移动终端的接收信号为:
其中, 和 分别表示基站上的天线 1和天线 2到移动终端的平坦衰落 信道参数,即信道状态信息, 和 分别表示移动终端在时刻 m(m = l,2) 接收到的信号和加性高斯 (Gaussian ) 白噪声。
接收端对被检测信号 和 的计算分别如下:
K ;
= ^h _
最后,移动终端可以利用最大似然准则对基站所发射的两个原始 信号 和¾分别进行检测判决 (detection ) 。
下面以四发射天线的系统为例, 对 STBC算法的实现方式进行说 明。 这时, 系统的发射矩阵结构为:
JC^ "^ ,
输的发射信号, *表示共轭运算。
具体来说, 移动终端在相邻 8个时刻对应的接收信号如下: rx = xx + h2x2 + ^^+^^+^ι '
其中, 表示基站上的天线 m(m = 1,2,3,4)到移动终端的平坦衰落信道 数, rm和 nm分别表示移动终端在时刻 m(m = 1,2,3,4,5,6,7,8)接收到的信号 和力口性 Gaussian白噪声;
四发射天线系统对于被检 'J信号 的计算分别为: χλ— νγ^ h2r2 + h r + h4r4 + r5 + h2r6 + h r7 + h4rs;
x2 = h2rx— r2 h4r3 + h3r4 + h2r5 ― rk h4r7 + h3rs;
x3 = }ι^νγ + h:r2 h*r3 h*r4 + h3 r5* + h4r: h2r^;
x4 =—h^ h r2 + h r3 h^r4 h4r h3r: + h2r; 。
不难看出, 当待传输的发射信号为复数信号时, 如果发射天线数 目多于两个, 则系统的等效传输速率只能达到单天线系统(SISO )系 统传输速率的一半, 降低了 MIMO系统的等效传输速率。
可见, 使用现有的 STBC算法时, 系统的误码率较高。 另外, 当 系统中的待传输的发射信号是两个或两个以上的复数时, 系统的传输 速率较低。 发明内容 本发明实施例提供了一种多天线无线通信系统中的空时编解码 方法及装置, 可以降低系统的误码率。
一种空时编码方法, 包括:
根据待传输的发射信号生成正交矩阵;
根据获取的信道状态信息, 生成对应所述正交矩阵的系数矩阵; 根据所述正交矩阵和所述系数矩阵生成发射信号矩阵;
根据所述发射信号矩阵, 进行信号发射。
一种空时解码方法, 包括:
获取接收信号, 所述接收信号对应的发射信号矩阵具有正交性, 根据信道状态信息, 对所述接收信号进行加权合并;
检测所述加权合并后的接收信号, 根据信道状态信息, 获取与所 述接收信号对应的发射信号的估计值。
一种空时编码装置, 包括:
正交矩阵构造模块, 用于根据待传输的发射信号生成正交矩阵; 系数矩阵确定模块, 用于根据信道状态信息, 生成对应所述正交 矩阵的系数矩阵;
发射信号矩阵形成模块, 用于利用所述系数矩阵对所述正交矩阵
中的各元素进行加权, 生成发射信号矩阵;
信号发射模块, 将根据所述发射信号矩阵, 通过发射天线进行信 号发射。
一种空时解码装置, 包括:
接收信号合并模块, 用于获取接收信号, 所述接收信号对应的发 射信号矩阵具有正交性, 对所述接收信号进行加权合并;
信号检测判决模块, 用于检测判决所述加权合并后的接收信号, 根据信道状态信息, 获取与所述接收信号对应的发射信号的估计值。
由上述技术方案可以看出, 在本发明实施例中, 利用发射端获取 的信道状态信息, 对待传输的发射信号进行空时编码, 降低了系统的 误码率, 提高了系统的误码性能。
另外, 本发明实施例利用发射端获取的信道状态信息, 对待传输 的发射信号进行空时编码, 避免了对待传输的发射信号进行共轭运 算, 当待传输的发射信号为两个或两个以上的复数信号时, 显著的提 高了系统的传输速率。 附图简要说明
图 1为现有两天线 STBC系统的结构示意图;
图 2为本发明实施例中空时编解码方法的流程图;
图 3为本发明实施例应用于两发射天线系统的误码率仿真结果示 意图;
图 4为本发明实施例应用于四发射天线系统的误码率仿真结果示 意图;
图 5为本发明实施例中空时编解码装置的结构示意图。
实施本发明的方式
本发明实施例提供的空时编码技术利用发射端已知的信道状态 信息, 对待传输的信息符号进行空时编码, 不仅能够提高系统的误码 率性能, 而且当系统中设置的发射天线数目多于两个时, 如果系统的 输入信号是复数信号, 本发明实施例还可以提高系统的等效传输速 率。
应用本发明实施例, 无论系统设置的发射天线数目是多少, 其等 效传输速率都与 SISO (单输入单输出) 系统的传输速率之比相等。
M是大于 2的整数, 如 2 , 3 , 4……。 如图 2所示, 本发明实施例中的 空时编码及译码处理过程具体包括以下步骤。
步骤 201:根据 M个待传输的发射信号生成一个 Μ χ Μ维的正交矩 阵 X。
假设系统中设置有 Μ个发射天线, 根据 Μ个待传输的发射信号生 成正交矩阵, 其中, 正交矩阵的第一行是 Μ个待传输的发射信号; ^、 χ2 χΜ , 其余各行由 Μ个待传输的发射信号或者 Μ个待传输的发 射信号的相反数的不同换序排列组成, 即由 ± 、 ± 2、 ... ± Μ构成 Μ χ Μ维的正交矩阵。
步骤 202: 根据发射端获取的信道状态信息计算发射信号矩阵中 各个元素所对应的系数,生成系数矩阵。在本实施例中, 系数矩阵为:
步骤 203 : 将正交矩阵 X左乘系数矩阵, 使正交矩阵中的各个元 素与其对应的系数矩阵中的元素相乘, 生成发射信号矩阵。 在本实施 例中, 发射信号矩阵为:
其中, 发射信号矩阵中的行对应同一时刻 M个发射天线上发射的 信号, 发射信号矩阵中的列对应同一发射天线在相邻 M个时刻发射的 信号。
步骤 204: 根据发射信号矩阵, 进行信号发射。
M个发射天线在 M个相邻的时刻分别将发射信号矩阵中的信号发 送到无线信道。 其中, 不同发射天线上所发射的信号依次对应发射信 号矩阵中的行中的不同元素; 同一发射天线在相邻时刻所发射的信号 依次对应发射信号矩阵的列中的元素。
在本发明实施例中, 可以预先对待传输的发射信号进行分组, 形 成待发射信号组, 进而针对每个待发射信号组进行空时编码操作。
接收端接收到发射信号后执行下述步骤。
步骤 205: 获取接收信号, 根据接收端已知的信道状态信息以及发 射信号矩阵具有的正交性, 对 M个相邻时刻的接收信号进行加权合并。
在本实施例中, 可以根据信道状态信息, 利用最大比合并的原则 计算接收信号的加权系数, 之后, 利用加权系数及发射信号矩阵的正 交性对接收信号进行加权合并。
步骤 206: 对加权合并后的接收信号分别进行检测判决, 获取与
接收信号对应的发射信号的估计值。
在本发明实施例中, 接收端同时接收来自发射端的训练序列, 用 于估计信道状态信息, 并将信道状态信息反馈给发射端。
下面分别以发射天线数目不同的系统为例,分别对本发明实施例 的最佳实施方式进行描述。
其中, 该发射信号矩阵中的每一行的 2个元素分别对应于在该行 对应的时刻 2个发射天线上发射的信号,发射信号矩阵中的每一列的 2 个元素分别对应于该列对应的发射天线在相邻 2个时刻发射的信号。 在该 和 c2分别表示两个待传输的发射信号, 表示基站的第 ( = 1,2)个发射天线到接收端的平坦衰落信道参数, 即信道状态信 息。
也就是说, 在时刻 1 , 发射天线 1和发射天线 2向移动终端发射的
+ \h
信号分别为' 和 + \h
端在时刻 1接收到的信号和加性 Gaussian白噪声;
终端在时刻 2接收到的信号和加性 Gaussian白噪声。
和
~ ¾|2 |2 最后, 移动终端可以利用最大似然准则对 和 分别进行检测判 决, 得到来自发射天线的两个发射信号的估计值。
图 3示出了本发明实施例应用于两发射天线系统的实施例的误码 率仿真结果, 如图 3所示, 虚线表示现有 STBC算法在两发射天线系统 中的误码率性能,实线表示本发明实施例在两发射天线系统中的误码 率性能。 从图 3可以看出, 在两发射天线系统中, 本发明实施例提供 的空时编码方法与传统的 STBC算法相比, 其信噪比增益大于 ldB , 也 就是说, 在误码率相同的情况下, 本发明实施例较之 STBC算法, 节 约了大于 ldB的发射功率; 在发射功率相同的条件下, 本发明实施例
提供的方法具有较低的误码率。
实施例二: 系统设置四发射天线, 接收端为单天线移动终端。 根据图 2所示实施例中的发射信号矩阵, 当 M的值为 4, 即四发射 天线系统中的发射信号矩阵如下:
其中, 、 2 、 3、 x4分另 ll表示四个待传输的发射信号, hm表示 基站的第 m (m = 1,2,3,4)个发射天线到接收端的平坦衰落信道参 数, 即信道状态信息。
该发射信号矩阵中每一行的 4个元素分别对应于在该行对应的时 刻 4个发射天线上发射的信号,发射信号矩阵中的每一列的 4个元素分 别对应于该列对应的发射天线在相邻 4个时刻发射的信号。
这样一来, 移动终端在相邻四个时刻的接收信号分别如下:
其中, r\、 r2、 r3、 r4和/ ^、 "2、 n3、 "4分另 ll表示移动终端在时刻 1 时刻 2、 时刻 3、 时刻 4接收到的信号和加性 Gaussian白噪声。
最后, 移动终端可以利用最大似然准则对 _¾、 _¾和 分别进 行检测判决, 得到来自发射天线的四个发射信号的估计值。
图 4示出了本发明实施例应用于四发射天线系统的实施例的误码 率仿真结果, 如图 4所示, 虚线表示现有 STBC算法在四发射天线系统 中的误码率性能,实线表示本发明实施例在四发射天线系统中的误码 率性能。 从图 4可以看出, 在四发射天线系统中, 本发明实施例提供 的空时编码方案与传统的 STBC算法相比, 其信噪比增益约为 2dB。也 就是说, 在误码率相同的情况下, 本发明实施例较之 STBC算法, 节 约了约 2dB的发射功率, 在发射功率相同的条件下, 本发明实施例提 供的方法具有较低的误码率。
实施例三: 系统设置八发射天线, 接收端为单天线移动终端 根据图 2所示实施例中的发射信号矩阵, 当 M的值为 8, 即八发射 天线系统中的发射信号矩阵如下:
其中, 分别表示八个待传输的 发射信号, ^表示基站的第 m(m = 1,2,3,4,5,6,7,8)个发射天线到接收端 的平坦衰落信道参数, 即信道状态信息。
该发射信号矩阵中每一行的 8个元素分别对应于在该行对应的时 刻 8个发射天线上发射的信号,发射信号矩阵中每一列的 8个元素分别 对应于该列对应的发射天线在相邻 8个时刻发射的信号。
在本实施例的八天线系统中, 移动终端在八个时刻的接收信号, 以及移动终端获得的来自发射天线的八个发射信号的估计值均可以 依据之前描述的两发射天线系统和四发射天线系统的处理方式类推 获得, 故不再赘述。
可见, 在本发明实施例中的空时编解码方法, 提高了系统的误码 性能, 无论待传输的发射信号是复数信号或者实数信号, 均能够降低 系统的误码率。
另外, 本发明实施例中的空时编解码方法, 避免了对待传输的发 射信号进行共轭运算, 当待传输的发射信号为复数信号时, 采用本发 明实施例, 能够显著提高系统的等效传输效率。
基于上述在多天线无线通信系统中空时编解码方法,本发明实施 例还提供了一种多天线无线通信系统中实现空时编解码装置。
图 5示出了本发明实施例中空时编解码装置的结构, 该装置包括 空时编码装置, 即发射装置以及空时解码装置, 即接收装置。
在本实施例中, 空时编码装置包括:
正交矩阵构造模块, 用于根据待传输的发射信号生成正交矩阵。 系数矩阵确定模块, 用于根据信道状态信息, 生成对应正交矩阵 的系数矩阵。
发射信号矩阵形成模块, 用于利用系数矩阵对正交矩阵中的各元 素进行加权, 生成发射信号矩阵。
信号发射模块, 将根据发射信号矩阵, 通过发射天线进行信号发 射。
其中, 正交矩阵构造模块进一步包括:
待传输信号分组单元, 用于根据系统中发射天线的数量, 对待传 输的发射信号进行分组。
正交矩阵生成单元,用于根据分组后的待传输的发射信号生成正 交矩阵, 正交矩阵的第一行元素为待传输的发射信号, 其余各行由待 传输的发射信号或者待传输发射信号的相反数的不同换序排列组成。
系数矩阵确定模块进一步包括:
信道状态信息获取单元, 用于接收信道状态信息。
系数矩阵计算单元, 用于根据信道状态信息, 生成系数矩阵。 系数矩阵计算单元根据如下所述公式, 生成系数矩阵,
其中, M为发射天线的数目, ^为发射端的第 m(m = 1,2,· · ·, M)个天 线到接收端的信道状态信息。
在本实施例中, 空时解码装置包括:
接收信号合并模块, 用于获取接收信号, 其中, 接收信号对应的 发射信号矩阵具有正交性, 对接收信号进行加权合并。
信号检测判决模块, 用于检测判决加权合并后的接收信号, 根据 信道状态信息, 获取与接收信号对应的发射信号的估计值。
信道状态信息估计模块, 用于估计信道状态信息, 并将信道状态 信息反馈至发射端。
空时解码装置进一步包括:
加权系数计算模块, 用于根据信道状态信息, 计算接收信号的加 权系数。
接收信号合并模块, 进一步用于根据加权系数, 对接收信号进行 加权合并。
上述各模块具体采用的处理方式参见前面的描述, 在此不再赘 述。
综上所述,在本发明实施例中,利用发射端获取的信道状态信息, 对待传输的发射信号进行空时编码, 降低了系统的误码率, 提高了系 统的误码性能。
另外, 本发明实施例利用发射端获取的信道状态信息, 对待传输 的发射信号进行空时编码, 避免了对待传输的发射信号进行共轭运 算, 当待传输的发射信号为两个或两个以上的复数信号时, 采用本发 明实施例, 能够显著提高系统的等效传输效率。
以上所述, 仅为本发明较佳的具体实施方式, 但本发明的保护范 围并不局限于此,任何熟悉本技术领域的技术人员在本发明公开的技 术范围内, 可以想到的变化或替换, 例如设计其它形式的正交矩阵结 构以及改变正交矩阵中各元素所对应的系数等,都不脱离本发明保护
的精神与内涵。 因此, 本发明的保护范围应该以权利要求的保护范围 为准。
Claims
1、 一种空时编码方法, 其特征在于, 包括:
根据待传输的发射信号生成正交矩阵;
根据获取的信道状态信息, 生成对应所述正交矩阵的系数矩阵; 根据所述正交矩阵和所述系数矩阵生成发射信号矩阵。
2、 根据权利要求 1所述的方法, 其特征在于,
所述发射信号矩阵中每一行中的各元素表示, 在该行对应的时刻。 各发射天线上所发射的信号; 所述发射信号矩阵中每一列中的各元素表 示, 该列对应的发射天线, 在各时刻所发射的信号。
3、 根据权利要求 1所述的空时编码方法, 其特征在于, 所述根据 待传输的发射信号生成正交矩阵之前进一步包括:
根据所述系统中发射天线的数量,对所述待传输的发射信号进行 分组。
4、 根据权利要求 1所述的空时编码方法, 其特征在于, 系统中设置 有 M个发射天线, 所述根据待传输的发射信号生成正交矩阵包括:
由 M个待传输的发射信号生成 M M维正交矩阵 X, 所述正交矩阵 的第一行元素为 M个待传输的发射信号; 、 x2、 ...、 xM , 其余各行由所述 待传输的发射信号或者所述待传输的发射信号的相反数的不同换序排 列组成。
5、 根据权利要求 1所述的空时编码方法, 其特征在于, 系统中设置 有 M个发射天线, 所述对应所述正交矩阵的系数矩阵包括:
6、 根据权利要求 1所述的空时编码方法, 其特征在于, 所述根据 正交矩阵和系数矩阵生成发射信号矩阵包括:
利用所述的系数矩阵, 对所述正交矩阵中的各元素进行加权。
7、 根据权利要求 6所述的方法, 其特征在于, 所述根据正交矩阵和 系数矩阵生成发射信号矩阵包括:
所述正交矩阵左乘所述系数矩阵。
8、 一种空时解码方法, 其特征在于, 包括:
获取接收信号, 所述接收信号对应的发射信号矩阵具有正交性, 根 据信道状态信息, 对所述接收信号进行加权合并;
检测所述加权合并后的接收信号, 根据信道状态信息, 获取与所述 接收信号对应得发射信号的估计值。
9、 根据权利要求 8所述的空时解码方法, 其特征在于, 该方法进 一步包括:
估计并发送所述信道状态信息。
10、 一种空时编码装置, 其特征在于, 包括:
正交矩阵构造模块, 用于根据待传输的发射信号生成正交矩阵; 系数矩阵确定模块, 用于根据信道状态信息, 生成对应所述正交矩 阵的系数矩阵;
发射信号矩阵形成模块, 用于利用所述系数矩阵对所述正交矩阵进 行加权, 生成发射信号矩阵;
信号发射模块, 用于根据所述发射信号矩阵, 通过发射天线进行信 号发射。
11、 根据权利要求 10所述的装置, 其特征在于, 所述的正交矩阵构
造模块包括:
待传输信号分组单元, 用于根据所述发射天线的数量, 对所述待 传输的发射信号进行分组;
正交矩阵生成单元, 用于根据所述分组后的待传输的发射信号生 成正交矩阵, 所述正交矩阵的第一行元素为待传输的发射信号, 其余 各行由所述待传输的发射信号或者所述待传输发射信号的相反数的 不同换序排列组成。
12、 根据权利要求 10所述的装置, 其特征在于, 所述的系数矩阵确 定模块包括:
信道状态信息获取单元, 用于接收信道状态信息;
系数矩阵计算单元, 用于根据所述信道状态信息生成所述系数矩 阵。
13、 根据权利要求 12所述的装置, 其特征在于, 所述的系数矩阵计 算单元根据如下公式, 生成所述系数矩阵:
其中, M为发射天线的数目, ^为发射端的第 m(m = l,2,. ,M)个天线 到接收端的信道状态信息。
14、 一种空时解码装置, 其特征在于, 包括:
接收信号合并模块, 用于获取接收信号, 所述接收信号对应的发 射信号矩阵具有正交性, 对所述接收信号进行加权合并;
信号检测判决模块, 用于检测判决所述加权合并后的接收信号, 根 据信道状态信息, 获取与所述接收信号对应的发射信号的估计值。
15、 根据权利要求 14所述的装置, 其特征在于, 进一步包括:
信道状态信息估计模块, 用于估计所述信道状态信息, 并将所述信 道状态信息反馈至发射端。
16、 根据权利要求 14所述的装置, 其特征在于, 进一步包括: 加权系数计算模块, 用于根据所述信道状态信息, 计算所述接收信 号的加权系数;
所述接收信号合并模块, 进一步用于根据所述加权系数, 对所述接 收信号进行加权合并。
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US20030133516A1 (en) * | 1997-10-31 | 2003-07-17 | Siavash Alamouti | Low complexity maximum likelihood detection of concatenated space codes for wireless applications |
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US20060050804A1 (en) * | 2002-06-14 | 2006-03-09 | Philippe Leclair | Method for decoding linear space-time codes in a multiple-antenna wireless transmission system and decoder therefor |
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CN111585580A (zh) * | 2020-04-01 | 2020-08-25 | 宁波大学 | 一种基于矩阵特征的stc最优子校验矩阵集合选取方法 |
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CN101317356A (zh) | 2008-12-03 |
US7675845B2 (en) | 2010-03-09 |
US20090116375A1 (en) | 2009-05-07 |
CN101170335A (zh) | 2008-04-30 |
CN101170335B (zh) | 2012-08-22 |
CN101317356B (zh) | 2012-12-19 |
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