Coded cooperative data exchange for multiple unicasts

The advantages of coded cooperative data exchange has been studied in the literature. In this problem, a group of wireless clients are interested in the same set of packets (a multicast scenario). Each client initially holds a subset of packets and wills to obtain its missing packets in a cooperative setting by exchanging packets with its peers. Cooperation via short range transmission links among the clients (which are faster, cheaper and more reliable) is an alternative for retransmissions by the base station. In this paper, we extend the problem of cooperative data exchange to the case of multiple unicasts to a set of n clients, where each client c_i is interested in a specific message x_i and the clients cooperate with each others to compensate the errors occurred over the downlink. Moreover, our proposed method maintains the secrecy of individuals´ messages at the price of a substantially small overhead.