Fundamental Bounds on Downlink Throughput of Cellular Networks

Throughput (or maximum sum rate) of the downlink in cellular networks has always been an issue of importance since it reveals the maximum capability of the networks. In this paper we employ an information-theoretic approach to establish upperbounds and lowerbounds on the throughput of the downlink in cellular networks. These bounds may serve as baselines for evaluating performance of practical transmission schemes. In a multiple input multiple output (MIMO) cellular architecture we use the zero forcing criterion to design the optimal number of antennas at each receiver given the number of antennas at each transmitter, thereby deriving a lowerbound for the total achievable multiplexing gain. This lowerbound is shown to meet the upperbound in certain cases.