用于宽带无线通信的空时频编码OFDM技术

为进一步改善频率选择性衰落信道下的空时编码系统性能，提出了一种系统误码性能更为优越、功率效率更高的空时频编码OFDM(COFDM)技术．该技术采用子载波分组与线性预编码方案，通过适当的子载波分组，可以保证系统获得最大的分集增益，并使系统编译码的的复杂程度大为降低；同时将空时格栅码(STTC)与空时分组码(STBC)相结合，使得系统在获得最大分集增益的前提下，具有良好的编码增益；最后引入功率配置来进一步改善系统误码率性能和提高功率效率．仿真结果表明，该方案具有良好的系统误码率性能和较高的功率效率．

Space-Time-Frequency Coded OFDM Technique for Broadb and Wireless Communications

An efficient space-time-frequency coded OFDM technique for broadband wireless communications was proposed. The proposed scheme adopts subcarrier grouping and linear precoding, which can guarantee the maximum diversity gain and facilitate the process of encoding and decoding.It jointly uses the space-time trellis codes (STTC) and the space-time block codes (STBC) to achieve higher coding gain. Power allocation is adopted in the scheme to achieve better bit error rate (BER) performance and higher power efficiency.The proposed scheme is a new approach to space-time-frequency coded OFDM (COFDM) that combines OFDM with space-time coding, linear precoding and adaptive power allocation to provide higher quality of transmission in terms of the error rate performance and power efficiency. The significant performance improvement of the design is confirmed by corroborating numerical simulations.