Dynamic code assignment improves channel utilization for bursty traffic in third-generation wireless networks

Emerging third generation (3G) wireless standards promise a "last-mile" solution capable of supporting mobile, wireless Internet service. The Third Generation Partnership Proposal (3GPP) wideband code division multiple access (WCDMA) standard will support data rates up to 2 Mbit/s with orthogonal variable spreading factor (OVSF) codes. These variable spreading factor codes provide a means of bandwidth allocation in a CDMA system. This paper presents a dynamic OVSF code assignment algorithm that efficiently shares a WCDMA downlink between data traffic sources with different quality of service (QoS) requirements. Both analytic and simulation results for bursty traffic sources demonstrate that our dynamic code assignment algorithm offers significant improvement in channel utilization over dedicated code assignment schemes.