一种无循环前缀的新型短波MB-OFDM系统

针对短波信道的特点,提出了适合低信噪比应用的一种无循环前缀的多子带OFDM系统.由于短波信道上相邻多径时延差一般达数毫秒,该系统利用快速的载波跳变来避免短波信道上多径信号引起的符号间干扰,同时不需要毫秒级的循环前缀,提高了传输效率.理论分析表明,使用Rake接收机可以使合成信号的幅度大大增加,很好地改善了短波衰落信道下系统的误码率性能.蒙特卡罗仿真结果验证了理论结果,表明这种MB-OFDM系统的性能随多径数的增加而改善.

Novel non -CP multi -band OFDM system in HF communications

To fi t the cha racter of HF cha nnels, a non-CP( cy cle prefix ) MB-O FDM ( multi-band o rthog onal f requency divi sio n multiplex ) system w as presented to be used under low SN R envi ronment. Because the time delay dif ference between adjacent paths w as usua lly sev eral milliseconds, thi s system used a fast hopping car rier to reduce ISI caused by mul ti-path in HF channels. At the same time, a CP lasting sev eral mi lli seco nds was redundant. Thus the t ransmission ef ficiency w as high. Theo retic analysis show ed the system w ith Rake receiv er could improve the ampli tude of combined path and raise the BER perfo rmance signi ficant ly. Monte Carlo simula tion result s v alida te the conclusio n and show that more improv ement is o btained w hen the pa th number increa ses.