应用于水声通信系统中的发射分集技术

空时分组码(STBC)是一种有效的抗衰落发射分集技术,以其较强的抗衰落性能和较低的译码复杂度而受到广泛的关注。文中将STBC引入水声通信中,将其与频移键控(FSK)调制相结合,形成STBC-FSK,可以基于简单的接收机结构,实现STBC的最大似然译码算法和FSK的非相干解调,获得完全发射分集。论文介绍了STBC-FSK的原理,给出其在多径信道和水声信道中的性能仿真。仿真结果表明,采用该系统,可以在不显著增加接收机复杂度的情况下,使水声通信系统的性能得到明显的改善。

Achieving 3 dB Transmit Diversity Gain in Transmission Performance over Multipath Underwater Acoustic Communication with STBC-FSK Scheme without Significant Increase in Complexity of Receiver Structure

Aim.Existing STC(Space-Time Coding) or STBC(Space-Time Block Coding) papers~() are still unable,in our opinion,to suppress ISI(Intersymbol Interference) in underwater acoustic channel.For suppressing ISI,there are several methods such as MIMO equalization,OFDM and FSK(Frequency-Shift Keying) modulation.We select FSK modulation after careful consideration;so,this paper employs STBC-FSK scheme.In the full paper,we explain STBC-FSK scheme in detail; In this abstract we just add some pertinent remarks to listing the one topic of explanation:(A) the principles of STBC-FSK scheme;Fig.1 in the full paper shows the schematic of STBC-FSK scheme;under topic A,we take eqs.(1) through(5) from the open literature;also under topic A,we discuss why FSK modulation is very effective inherently in mitigating frequency selective fading;still under topic A,we discuss how FSK modulation can achieve non-coherent demodulation in signal detection.Finally we performed numerical simulations,whose results are shown in Figs.2 and 3 in the full paper;these results demonstrate preliminarily that the 3dB or more diversity gain with STBC-FSK scheme was achieved with two transmitting transducers and without significant increase in complexity of receiver structure.