Cooperative caching for shared spectrum networks

This paper considers cooperation between primary and secondary users in shared spectrum radio networks via caching. A network consisting of a single macro (primary) base-station and multiple small (secondary) base-stations is considered. Secondary base-stations can cache some primary files and thereby satisfy content requests generated from nearby primary users. For this cooperative scenario, we develop two caching and scheduling policies under which the set of primary and secondary user request generation rates that can be supported increases from the case without cooperation. The first of these algorithms provides maximum gain in the set of supportable primary and secondary request generation rates. However under this algorithm primary packet transmissions from secondary base-stations do not have higher priority than that of secondary packets. As a result, we propose another sub-optimal (with respect to set of supportable request generation rate vectors) algorithm wherein primary packet transmissions from secondary base-stations have higher priority than that of secondary packets. Extensive simulations are conducted to compare the performance of both algorithms with that of a non-cooperative algorithm that is optimal, with respect to set of supportable request generation rates, among all noncooperative policies.