Mesh Assisted Broadcasting in IEEE 802.16 Mesh Mode

The IEEE 802.16 standard for wireless metropolitan area networks allows communications between subscriber stations (SS) through the utilization of the optional Mesh operation mode. In mesh mode, the network base station can centrally schedule transmissions by routing packets on the links of a tree rooted at the BS and covering the mesh network. In this study, strategies for improving the reliability of the message broadcasting from the BS to the SSs are proposed and evaluated. By using the, so called, mesh assisted broadcasting (MAB) strategies, SS may exploit the higher connectivity degree offered by the mesh network during reception and may optionally cooperate with other SSs during the retransmission. MAB strategy performance is evaluated analytically and through simulations. Due to the complexity of the computational problem, analytical models are developed only for the MAB strategies for which the probability that an SS correctly receives a broadcast message can be obtained in closed form. Analytical and simulation results show that MAB strategies may turn the inherent broadcast nature of the radio medium into an increase of broadcasting reliability with respect to the tree-based broadcasting strategy defined in the IEEE 802.16 standard.