A Factor Graph Based Dynamic Spectrum Allocation Approach for Cognitive Network

Cognitive radios share the whitespace in the absence of licensed users. For spectrum sharing, avoiding the interference among multiple secondary users is a fundamental problem (known as dynamic spectrum allocation problem). This paper proposes a factor graph based approach to solve the dynamic spectrum allocation problem in an efficient manner. With the proposed DWA-Tree (Distributed Wave Algorithm), this problem can be solved with 2n number of messages for tree structured graphs. This paper also proposes another novel algorithm called DWA-Cycle to solve the problem for general graphs with cycles. Simulation results show that both DWA-Tree and DWA-Cycle can improve the global link quality consistently better than naive local optimization approaches.