a distributed underlay channel assignment for cognitive cooperative ad hoc networks based on interference temperature
In this paper, we develop a single user and a multi user version of a Distributed Underlay Channel Assignment (DUCHA) algorithm for spectrum access to a downlink channel of a primary cell for a cognitive cooperative ad hoc network overlaid with the cell. We use direct sequence spread spectrum as a medium interface for cognitive links. We investigate performance of DUCHA algorithm in three spreading scenarios with regard to the bandwidth of the channel. Simulation results show that when there are 100 cognitive channel applicants and spreading factor is 100 the multi user DUCHA algorithm assigns the channel to an average 51.8 percent of channel applicants and in this case it achieves 22.57 bps/Hz spectral efficiency under high power interference from the primary base station of the cell. We show that in this condition the increased in-band and out of band interference temperatures are non-harmful and have values of respectively 22.48 dB and -0.99 dB .
direct sequence spread spectrum jammer suppression underlay transmission cognitive radio