【摘要】 传统直接序列扩频(DSSS)通信由于采用固定的PN码作为扩频码,其通信安全潜在着极大威胁。介绍一种完全抛弃传统的PN码而利用当前N个信码比特作为下一个信码的扩频码码片来进行扩频调制的新的扩频——自编码直接序列扩频(SEDS)通信技术。本质上自编码扩频是一种随机直接序列扩频(RCDS),理论分析和仿真均表明在单用户AWGN信道上当信噪比大于4dB时误码性能与传统直扩通信基本相同,采用适当的纠错码技术在Pe为10-4时可获得近4dB编码增益,与传统直扩多址相比,可能有更大的多址用户数。但由于目前自编码扩频的无冗余延迟抽头结构使扩频码本质上没有严格的0/1平衡性,必然存在载波泄漏等安全隐患。最后还指出了自编码扩频通信技术的一些改进研究方向。更多还原

【Abstract】 The security of conventional spread spectrum communication has been prodigious threaten as the fixed pseudo-random (PN) codes been the spread spectrum codes[2]. A novel spread spectrum system called the self-encoded direct sequence spread spectrum (SEDS) is introduced, which fully eliminates the use of PN codes as spread spectrum code instead of just using current N information bits as the spread sequence chips of the next one. The SEDS is a sort of random-coded direct sequence spread spectrum in itself. Compared with the conventional direct-sequence spread spectrum single user systems in AWGN channel, it is almost the sameness when signal-noise rate greater than 4dB and about 4dB or more gains when Pe equals to 10-4 if a suitable error-correct code adopted. Furthermore, the SEDS may achieve larger capability than conventions in multi-access application. For there is no redundancy in the tapping architecture used in the current SEDS system, the spread spectrum codes in SEDS is essentially unbalance of 0抯 and 1抯 and results in carrier leakage inherently. At last some directions in further modifications are pointed out.更多还原