Abstract:Redundant packets are used to increase the possibility of successful decoding in fountain-code based code dissemination protocols.The problem on the selection of the optimal block redundancy length was investigated.Theoretical analysis and experimental results show that the optimal block redundancy length which meets the minimum traffic condition is related to packet loss rate.Under typical indoor interference conditions,the optimal block redundancy length is positively correlated with the packet loss rate.When the packet loss rate increases,increasing the block redundancy length can reduce traffic.The fountain-code based code dissemination protocol and its improved version were implemented on a platform with CC2430 as the core.A mechanism for adaptively adjusting the block redundancy length was added to the improved version.A series of performance evaluation experiments were carried out in the actual environment.The experimental results show that,with the aid of dynamically adjusting the block redundancy length the overall traffic can be reduced by about 15.3%,and the dissemination time is also significantly shortened,which will help to prolong the lifetime of wireless sensor networks.