Delay-throughput tradeoff for overlaid wireless networks of different priorities

We study the delay-throughput tradeoffs for two coexisting wireless networks that operate in the same geographic region. The primary network consists of Poisson distributed legacy users of density n, and the secondary network consists of Poisson distributed cognitive users of density m, with m > n. The primary users have a higher priority to access the spectrum without particular considerations for the secondary users, while the secondary users have to act conservatively in order to limit the interference to the primary users. With a practical assumption that the secondary users only know the locations of the primary transmitters (not the primary receivers), based on our previous work in, we show that both networks can achieve the same delay-throughput tradeoff as the optimal one established by El Gamal et al. for a stand-alone wireless network.