Wireless data performance in multi-cell scenarios

The performance of wireless data systems has been extensively studied in the context of a single base station. In the present paper we investigate the flow-level performance in networks with multiple base stations. We specifically examine the complex, dynamic interaction introduced by the strong impact of interference from neighboring base stations. We derive two types of lower and upper bounds for the number of active flows, transfer delays and flow throughputs in the various cells. While the first type of bounds are rather rough and simple to compute, the second type of bounds are sharper, but harder to calculate. In order to obtain closed-form estimates for the latter bounds, we introduce two limit regimes, termed fluid and quasi-stationary regime, where the system dynamics evolve on a very fast and a very slow time scale, respectively. Importantly, the performance in both limit regimes is insensitive, thus yielding simple, explicit estimates that render the detailed statistical characteristics of the system largely irrelevant. Numerical experiments show that the upper bounds evaluated in the quasi-stationary regime provide conservative and extremely tight approximations.