Throughput of network coding nodes employing go-back-N or selective-repeat automatic repeat request

The steady-state performance of general network coding nodes is investigated, when data are transmitted in packets based on the go-back-N automatic repeat request (GBN-ARQ) or selective-repeat ARQ (SR-ARQ) error-control scheme. A general network coding node is assumed to have H incoming links that provide packets for forming the coded packets transmitted by one outgoing link. Each of the incoming and outgoing links is assumed to have some buffers for temporarily storing the data packets. The state transitions of network coding nodes employing GBN-ARQ or SR-ARQ are analyzed, which shows that the operations of a general network coding node can be modeled by a finite state machine. Therefore, the expressions for the steady-state throughput of general network coding nodes are derived based on the properties of finite-state machines. Furthermore, the throughput performance of network coding nodes is investigated by both simulations and evaluation of the expressions obtained. The studies show that the simulation results converge closely to the numerical results, which justify the effectiveness of the analytical expressions derived. Furthermore, the studies show that the packet error rate, the capacity of buffer, and the number of incoming links may impose significant impact on the performance of general network coding nodes.