Downlink Radio Resource Allocation for Multi-Cell OFDMA System

Abstract

This paper presents a radio resource control (RRC) scheme for OFDMA systems where dynamic resource allocation is realized at both a radio network controller (RNC) and base stations (BSs). The scheme is semi-distributed in the sense that the RRC decision is split between RNC and BSs. RNC makes decision on which channel is used by which BS at super-frame level and BSs then make decision on which user is assigned to which channel at frame-level. Two optimization problems for RNC and BSs are formulated and computationally efficient algorithms that perform the function of interference avoidance and traffic/channel adaptation are developed. Numerical analysis is performed under several cell configurations to show tradeoffs between sector interference suppression and dynamic interference avoidance. The results indicate that with reasonable signaling overhead, the protocol and the associated algorithms yield excellent performance for both real-time and non real-time services, even under fast fading