Lightweight Localized Network Coding Aware Mechanism

Because of the broadcast nature of wireless networks, network coding technology has been research deeply in wireless networks. Packets in the encoding and decoding operations are performed within localized in the localized network coding. Most of current localized network coding used τ interval notification mechanism of COPE.This article focuses on the localized network coding aware mechanism. For sending reception reports can bring some overhead in COPE, we propose a new coding strategy without sending reception reports and a lightweight adaptive report sending mechanism. Our purpose is to reduce the notifications consideration, while improving the coding efficiency. The main works are as follows:We test coding overhead τ interval notification mechanism, simulation experiments show that τ is smaller, the encoding overhead of nodes sending and receiving the report is large, and the impact on network is greater.We propose a new coding aware mechanism NCBNT without sending reception reports. In NCBNT, the coding node only based own neighbor topology relationship and path information of the packet to determine whether the data packets can be encoded or not. There is no need to send additional information. But direct encoding brings many encoded packets can’t be decoded. Further, we reduce the percentage of encoding package can not be decoded through adding the listener list and clearing cache strategy in NCBNT. Compared with τ interval notification mechanism, simulation results show that NCBNT improves encoding times and throughput of network effectively, the percentage of encoding package can not be decoded is still about10%.NCBNT can’t further reduce the percentage of encoding package can not be decoded, we analyze the reasons that NCBNT can not decode all coded packets. We find that hidden station problem due to the competition in the wireless network MAC layer, resulting in some of the nodes in the communication range of listeners, but could not listen to all packets that are used to decode. In order to improve the decoding rate and reduce the overhead of τ interval notification mechanism, we propose ARSM that each node relies on listen the number of data packets to decide sending a reception report time. It effectively reduces the overhead of the sending reception report in network, at the same time it will not affect the coding efficiency. Simulation results show that ARSM has better coding efficiency, generates less reception reports and has a higher effective throughput than τ interval notification mechanism.