The system composition, communications protocol and software system of an improved multi channel access telephone are presented.

Since it is very difficult to compute the sum rates capacity of Gaussian MIMO broadcast channels directly by using dirty paper coding approach,an iterative water-filling algorithm is proposed to obtain the sum capacity bound for multi-access channel and a suboptimal transmission policy to achieve the capacity bound is derived from the algorithm.

The capacity region with average power constraints of MIMO fading multi-access channels based on minimum rate requirements is analyzed and the optimal power allocation strategy is suggested.

Current routing protocol cannot sufficiently implement multi-channel and multi-interface in Mobile Ad Hoc networks(MANET).

Adopting the multi-channel receiver to realize HF signal direction finding,the radio design scheme of multi-channel receiver is proposed based on the characteristics of the receiving sensitivity,anti-interference ability,gain and phase coherence.

Low density parity check codes are used to multiple access channels and the user-specific check matrices are used as the unique characteristics.

Based on the concepts of broadcast channel and multiple access channel, a novel half-duplex relay strategy was proposed, and optimal resource allocation under this strategy was investigated.