Uplink User Capacity in a CDMA System with Hotspot Microcells: Effects of Finite Transmit Power and Dispersion

TL;DR

This paper analyzes uplink user capacity in two-tier CDMA systems with microcells under finite power and fading effects, developing analytical methods validated by simulations.

Contribution

It introduces novel analytical techniques to estimate user capacity considering power constraints and fading in multicell CDMA systems.

Findings

Analytical estimates match simulation results.

Fading and power constraints significantly impact capacity.

Extended methods applicable to multicell configurations.

Abstract

This paper examines the uplink user capacity in a two-tier code division multiple access (CDMA) system with hotspot microcells when user terminal power is limited and the wireless channel is finitely-dispersive. A finitely-dispersive channel causes variable fading of the signal power at the output of the RAKE receiver. First, a two-cell system composed of one macrocell and one embedded microcell is studied and analytical methods are developed to estimate the user capacity as a function of a dimensionless parameter that depends on the transmit power constraint and cell radius. Next, novel analytical methods are developed to study the effect of variable fading, both with and without transmit power constraints. Finally, the analytical methods are extended to estimate uplink user capacity for multicell CDMA systems, composed of multiple macrocells and multiple embedded microcells. In all cases, the analysis-based estimates are compared with and confirmed by simulation results.