Abstract:

The traditional fixed bit rate communication scheme has time delay and multiple feedback in large scale network, which affects the transmission performance of wireless sensor network (WSN). And rateless code, which changes its transmission rate according to real-time channel state, can solve this problem very well. This paper designs the distributed cooperative transmission mechanism in accumulate rateless (AR) code based on the multiple source relay network model, and makes the detailed elaboration and analysis of the transmission phases of broadcasting, forwarding and decoding. Then it optimized the degree distribution of AR code jointly in the scheme using the methods of extrinsic information transfer (EXIT) and convex optimization. By the simulation results and comparative analysis, the proposed distributed degree optimization scheme of AR code is obviously better than the LT scheme of classical distribution in error floor. And compared with the existing Raptor scheme and the AR code singleness distribution optimization scheme, the code rate reciprocal is reduced by 1.3% and 3.7% respectively.

Key words: wireless sensor network (WSN), internet of things (IoT), rateless code, convex optimization, degree distribution