中文摘要：

电磁波在自由空间中的全向辐射特性在无线通信领域一直被认为是一个巨大缺点,但在网络环境下该特性可被用来提高无线通信系统的性能.考虑在一个无线网络中,M个节点通过一个交换节点来相互交换各自信息.不同于传统传输方式,交换节点将对自己接收到的这M份独立信息进行联合编码,再利用电磁波全向辐射特性向所有节点同时发送相同码字.对于这种新型网络编码方式,本文给出了它对应的M维空时纠错码的数学定义,并证明了一些关于码本性能的基本定理,为构造性能较好的码本奠定了基础.这种同时引入空域和时域冗余的纠错码本有效地提高了发射天线电磁能的利用率,因此可以出设计高码率且检错纠错性能较好的码本,同时带有数据分布式处理特点的译码算法也可以有效降低复杂度.值得强调的是,新型码本的实例已经推翻了纠错码理论中具有检错纠错功能的码本码率不能为1的传统思维.

英文摘要：

In wireless communication field,the omnidirectional radiation of electromagnetic wave in free space is always considered as a big shortcoming,nevertheless,it can be used to improve the performace of wireless communication system in network entironment.Here,we consider that M nodes use a switch node to exchang their information in a wireless network.Differert from the conventional method,the switch node will take the joint coding method for the M independent information,then transmit the same codeword to all M nodes simultaneously through the omnidirectional radiation.For the novel network code,the mathematical definition of the M-dimension space-time error correction code is proposed,and some theorems about its performance are proved to lay a foundation to construct good codebooks.The redundancy of time and space domain is added to the novel codebook at the same time,and the efficiency of the transmit power is improved,so we can design high-rate codebook with good error detection and correction capability.Moreover,the complexity of its decoding algorithm can be reduced,owing to the distributed data processing.Here,we emphasize that contrary to one＇s intuition,our proposed codebook reveals that it is in general not correct to take the rate of codebook which has the error detection and correction capability to be less than 1.