基于空时分组编码的OFDM系统频率分集方案

增加发送或接收天线的个数可以提高无线通信系统分集增益和性能,但通过增加天线个数往往会大大增加系统的尺寸和成本,尤其是对于接收端显然是不现实的.针对空时分组编码正交频分复用(STBCOFDM:Space-Time Block Coded Orthogonal Frequency Division Multiplexing)系统提出频率分集方案,在相同符号错误率(SER:Symbol Error Rate)条件下,利用频率分集无须增加发送天线的个数.分析了该方案成对错误概率(PEP:Pairwise Error Probability)的上限值,给出了系统的编码增益和分集增益.结果表明,该方案可同时获得频率分集和空间分集增益.仿真实验证实了该方案在10-3符号错误概率条件下,与2发1收的STBC-OFDM系统相比,信噪比增益提高3 dB,与4发1收的STBC-OFDM系统具有几乎相同的误码性能.

Frequency Diversity Scheme for OFDM Systems Based on Space-Time Block Coding

Diversity gain and performance of wireless communication system can be improved by increasing the number of transmit or receive antenna. However, it is impractical to receiver because the size and cost of system can be greatly enhanced by increasing the number of antenna. A frequency diversity scheme for STBC-OFDM(Space-Time Block Coded Orthogonal Frequency Division Multiplexing) systems is proposed. Under the same SER (Symbol Error Rate) performance, the number of transmit antenna is not required to be increased because of using frequency diversity. The upper bound of PEP (Pairwise Error Probability) of the proposed scheme is analyzed. The coding and diversity gain is derived. The result shows that the improve 3 dB as STBC-OFDM systems with two transmit antennas and a single receive antenna and almost has the same performance as STBC-OFDM systems with four transmit antennas and a single receive antenna.