A Distributed Packet Scheduling Scheme with Interference Avoidance for Non Real-Time Applications in CDMA Networks

Abstract

In this paper, a packet scheduling scheme based on real-time channel conditions and dominant intercell interferer avoidance is proposed, studied and evaluated for reverse links in a time-slotted code division multiple access (CDMA) system. This scheme is implemented by distribution of tags by receivers among transmitters. Each base station issues M(≥1) tags to M mobile users based on the ranked reverse link gains in every slot. M=1 corresponds to spread-spectrum time division multiplexing mode operation and M≥1 corresponds to scheduling multiple simultaneous transmissions as in the traditional CDMA systems. The number of issued tags is a system parameter which depends on the expected traffic, the number of cells and the propagation conditions in the network. In the proposed scheme, users who not only have stronger channel gains to their respective home base stations but also cause relatively lower intercell interference are scheduled for transmissions. Different classes of tags can be issued and various scheduling decision rules can be implemented giving flexibility in interference management. Simulation results in shadow and multipath fading environment are presented to show the performance advantage of the proposed scheme.