BENCHMARKING OF OFDM SPECTRUM EXCHANGE INFORMATION FOR COOPERATIVE SPECTRUM SENSING IN MOBILE COGNITIVE RADIO NETWORKS

Abstract

In spectrum sensing scenario, the objective of the local spectrum sensing is to detect the PU’s signal detection. The performance of SN ability to sense the PU’s signal is crucial. How the PUs signal are sensed, sampled and processed in relation to how SN cooperates with each other is the fundamental elements of cooperative spectrum sensing. However, in most of the SN in CRN is assumed stationary. This model is insufficient for wireless nodes that are mobile. Moreover, algorithm that manages wireless nodes mobility in traditional wireless networks has a high cost in terms of communication overhead. Incidentally, to reduce the overhead and overcoming the problem with an unreliable SN reporting channel, exchanging and sharing observed information between SNs within cooperative sensing areas are needed. To achieve this, every sensing result representing the PU’s activity gathered by SNs must be collected. However, the studies assumed that the SN station is stationary. Most of the CR research does not consider the mobility of SN. However, the mobility of the PUs and SNs heavily influence the detection performance on local observation. The movement of the SNs create spatial diversity in the observation of the PU’s signal. Due to the movement, spatial distance, velocity, Doppler Effect and geo-location information, the signals condition would fluctuate during the sensing process. Mobility’s speed also reduces the average received signal strength and must be compensated by spatial diversity. On the other hand, mobile SN can improve the detection performance with its local observation’s samples and minimal cooperation from others to reduce the cooperation overhead, depending on the speed and the direction of the movement.