Multicast Traffic Throughput Maximization through Dynamic Modulation and Coding Scheme Assignment in Wireless Sensor Networks

The paper studies the following question: to what extent traffic throughput of a wireless sensor network (WSN) can be increased when dynamic assignment of modulation and coding schemes (MCS) is applied. We assume a TDMA-based scheme that is capable of changing the MCS used by the broadcasting nodes from a time slot to a time slot of the frame. The traffic throughput is measured by the size of the frame (the smaller the size the larger the throughput) that is necessary to carry the assumed volumes of data produced cyclically by the multicast traffic sources (e.g., sensors). Since we consider multi-hop networks, this means that the per-cycle data volume produced by each source must be delivered to all nodes in its multicast routing tree within one frame time-span. To answer this question we introduce a mixed-integer programming formulation of the related optimization, and use it in a numerical study that illustrates possible gains of dynamic MCS assignment. The presented optimization model is novel since only its unicast counterparts have been considered so far.