摘要
Spread spectrum is suitable for long-range or low-SNR underwater acoustic communication. But the low bandwidth efficiency of spread spectrum and limited underwater channel bandwidth cause low bit rates. So we propose the method of orthogonal M-ary/DS spread spectrum to improve bandwidth efficiency and bit rates; this method is a combination of orthogonal direct sequence (DS) spread spectrum and parallel M-ary spread spectrum. We introduce orthogonal M-ary/DS spread spectrum method and RAKE receiver. Experimental results in a lake show that, by use of Gold sequences of 63 and 127 lengths, the orthogonal M-ary/DS spread spectrum system achieved error-free communication of 480 symbols at 25 km and 0 dB SNR with RAKE receiver; the bit rates were up to 381.0 bits/s and 220.5 bits/s. In comparison with direct sequence spread spectrum using same sequences, the bandwidth efficiency of the new method increases by about an order of magnitude.
源语言 | 英语 |
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页(从-至) | 463-467 |
页数 | 5 |
期刊 | Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University |
卷 | 24 |
期 | 4 |
出版状态 | 已出版 - 8月 2006 |