Performance Bounds and Associated Design Principles for Multi-Cellular Wireless OFDMA Systems (with Detailed Proofs)

TL;DR

This paper derives performance bounds and scaling laws for multi-cellular OFDMA networks, providing insights into system capacity and guiding design principles for service providers and regulators.

Contribution

It introduces novel bounds on sum-utility in multi-cellular OFDMA systems and establishes scaling laws under various network configurations and fading models.

Findings

Sum capacity scales as Θ(B log log K/B) for extended networks.

Capacity bounds depend on network geometry and fading models.

Guidelines for network design and regulation are proposed.

Abstract

In this paper, we consider the downlink of large-scale multi-cellular OFDMA-based networks and study performance bounds of the system as a function of the number of users $K$, the number of base-stations $B$, and the number of resource-blocks $N$. Here, a resource block is a collection of subcarriers such that all such collections, that are disjoint have associated independently fading channels. We derive novel upper and lower bounds on the sum-utility for a general spatial geometry of base stations, a truncated path loss model, and a variety of fading models (Rayleigh, Nakagami-$m$, Weibull, and LogNormal). We also establish the associated scaling laws and show that, in the special case of fixed number of resource blocks, a grid-based network of base stations, and Rayleigh-fading channels, the sum information capacity of the system scales as $\Theta(B \log\log K/B)$ for extended networks, and as $O(B \log\log K)$ and $\Omega(\log \log K)$ for dense networks. Interpreting these results, we develop some design principles for the service providers along with some guidelines for the regulators in order to achieve provisioning of various QoS guarantees for the end users and, at the same time, maximize revenue for the service providers.