Topology-Independent Link Activation Scheduling Schemes for Mobile CDMA Ad Hoc Networks

In this paper, we study medium access control (MAC) protocols with quality-of-service (QoS) support, that is, topology-independent link activation transmission scheduling, for mobile code-division multiple-access (CDMA) ad hoc networks. QoS provisioning for each communication link is guaranteed without the need to adopt transmission schedules in mobile environments. An interference model, which captures the difference between transmission and interference ranges, is considered. Under this interference model, an approach to guaranteeing conflict-free transmission slots in each frame (QoS provisioning) for each communication link is proposed. Compared with the previously known method, superior performance is obtained. We then present a topology-independent link activation scheduling framework based on the theory of group-divisible (GD) designs. By the mathematical properties of GD designs, the proposed framework guarantees conflict-free transmission slots in each frame for each communication link, without the overhead due to the recomputation of transmission schedules when the network topology changes. With the proposed framework, we study and evaluate one series of GD design constructions. Based on the results derived, topology-independent link activation scheduling algorithms are then presented. The proposed schemes are designed for different objectives: maximizing the minimum system throughput and/or minimizing the schedule frame length. Numerical results show that the proposed algorithms outperform previously known schemes. The average performance of the proposed schemes is also derived.