QoS Protection in Cognitive Wireless Mesh Networks

Cognitive radio exploits unused frequency channels (holes) to increase a communication system´s overall capacity. These licensed frequency holes must however be released when their primary users become active. The unpredictable nature of the occupancy of frequency holes by primary users in addition to variability in the quality of wireless channels leads to situations where the promised quality of service (QoS) cannot be guaranteed solely by using traditional mechanisms, i.e. call admission control, bandwidth reservation, queue management and packet scheduling. We develop here an architecture which extends the failure protection mechanisms used in MPLS networks to protect QoS for cognitive wireless mesh networks. The proposed architecture ensures automatic QoS protection (QoSP) comprising guard-margin admission control, QoS degradation detection, notification and path recovery mechanisms. Simulation results show that the proposed architecture reduces the likelihood of QoS outage by one to three orders of magnitude. The proposed architecture and mechanisms can also be adapted to any other kinds of wireless networks where high fluctuations in the capacity of wireless links are expected.