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背景本《通信系统》不仅可用于一般通信,而且特别适用于由于信号衰落和多径失真而遭受信息损失的系统。在上述情况下,通信系统需要采用特殊的技术降低误码率,以改善通信的可靠性。以前改善通信系统可靠性的方法是空间分集、频率分集或频率扫描分集。带内编码系统也已用来改善通信的可靠性。这些系统所发射的信息是一群具有多余度的用符号代表的信号,因此即使接收的符号比这群符号少,也足以判别出发送的信息。在所有已知的带内编码系统中,根据发射符号中的一部分即足以恢复全部信息,但接收一定数量的符号还是必要的。
Background This “communication system” can be used not only for general communication but also for systems that suffer from loss of information due to signal fading and multipath distortion. Under the above circumstances, the communication system needs special techniques to reduce the bit error rate so as to improve the reliability of communication. Previous approaches to improve the reliability of communication systems have been spatial diversity, frequency diversity, or frequency sweep diversity. In-band coding systems have also been used to improve the reliability of communications. The information transmitted by these systems is a group of symbolically represented signals with redundancy, so that even if less symbols are received than the group of symbols, it is sufficient to discern the information being transmitted. In all known in-band coding systems, it is sufficient to recover the entire information based on a part of the transmitted symbols, but it is still necessary to receive a certain number of symbols.