TSD-CDMA: a QoS MAC protocol for 4G integrated mobile wireless systems

In this paper, we propose time/space-division CDMA (TSD-CDMA), a TCDMA MAC protocol for 4th-generation (4G) integrated wireless networks. We propose several novel mechanisms for TSD-CDMA to work efficiently in combination with a distributed CDMA protocol. Such a complementary MAC approach greatly increases the scalability of TSD-CDMA networks. We propose novel approaches based on differentiated orthogonal-code channels and directional mutual interference metric for power-controlled variable-radius multiple access with directional antennas, leading to low power and high throughput. We also employ differentiated channel access, prioritized scheduling, differentiated CDMA disciplines, wireless MPLS, and several other QoS differentiation mechanisms for DiffServ and QoS guarantees in TSD-CDMA. We show through simulations that wireless tree channel access of TSD-CDMA can achieve high utilization and bounded delay, reducing the control channel overhead and enhancing its QoS provisioning capability.