Analytical Modeling of Uplink Cellular Networks

TL;DR

This paper introduces a novel analytical model for uplink cellular networks using point processes, providing accurate, insightful, and easy-to-evaluate expressions for coverage probability considering user-base station dependence and power control.

Contribution

It develops a new point process-based uplink model that accounts for user-base station dependence and power control, offering a practical tool for system design analysis.

Findings

Partial channel inversion is optimal at low SINR.

Full power transmission is optimal at high SINR.

The model enables analysis of power control strategies in uplink networks.

Abstract

Cellular uplink analysis has typically been undertaken by either a simple approach that lumps all interference into a single deterministic or random parameter in a Wyner-type model, or via complex system level simulations that often do not provide insight into why various trends are observed. This paper proposes a novel middle way using point processes that is both accurate and also results in easy-to-evaluate integral expressions based on the Laplace transform of the interference. We assume mobiles and base stations are randomly placed in the network with each mobile pairing up to its closest base station. Compared to related recent work on downlink analysis, the proposed uplink model differs in two key features. First, dependence is considered between user and base station point processes to make sure each base station serves a single mobile in the given resource block. Second, per-mobile power control is included, which further couples the transmission of mobiles due to location-dependent channel inversion. Nevertheless, we succeed in deriving the coverage (equivalently outage) probability of a typical link in the network. This model can be used to address a wide variety of system design questions in the future. In this paper we focus on the implications for power control and see that partial channel inversion should be used at low signal-to-interference-plus-noise ratio (SINR), while full power transmission is optimal at higher SINR.