Impact of Network Load on Forward Link Inter-Cell Interference in Cellular Data Networks

Abstract

We study the impact of network load in the neighboring sectors on the inter-cell interference in a cellular data network. The signal received by a user over the forward link in such a system contains interference from the neighboring base stations. We note that the strength of this interference is a function of the network load in the neighboring cells. We obtain an expression for the received SINR (signal to interference and noise ratio) as a function of the traffic load in the interfering cells. Using this result, we propose an improvement to the conservative pilot-based SINR estimation scheme that is implemented in the current cellular data networks. The proposed scheme provides a more accurate estimate of the user SINR by taking better account of the contribution of inter-cell interference. It builds on top of the current SINR measurement scheme by using a combination of pilot measurement and traffic load measurement. With the proposed scheme, a terminal reports a less conservative data rate, and hence it receives a higher throughput. The scheme especially benefits the "poor" users, i.e., the users that receive low throughput because they are located far from the base station. For example, when the network load in the neighboring sectors is 0.5, with the proposed scheme, the throughput received by a single vehicular user located about three-fourth of the way between the serving base station and the cell boundary, is about 35% higher than the throughput obtained using the scheme that is used in current practice