Performance comparison of ARQ schemes for network coding in ad hoc networks

One of the solutions to mitigate degradation due to traffic concentration on certain nodes is network coding in ad hoc networks. When network coding is applied to unicast traffic, it is necessary to satisfy two condition; (a) an encoding node has to know which packets the neighbor node stores, and (b) decoding nodes have to hold all native packets encoded in the received packet except for the desired native packet. Because of these conditions, some retransmission schemes can be considered. In our study, we propose three retransmission schemes for network coding in ad hoc networks, and compare the performance. From the result, it is found that the scheme in which decoding nodes that fail in decoding the received packet and return NACK to the encoding node decreases the overflow rate the most.