On Spectrum Probing in Cognitive Radio Networks: Does Randomization Matter?
In cognitive radio networks, dynamic spectrum access is achieved by allowing secondary users (SUs) to probe the spectrum and utilize available channels opportunistically. Spectrum probing mechanisms should be efficient and fast to avoid harmful interference with primary users (PUs). Periodic probing has been commonly adopted as a default spectrum probing mechanism. In this paper, we attempt to study different spectrum probing mechanisms and evaluate a performance metric called the probing delay, i.e., how quickly a probing mechanism can detect a channel change. We find that randomization in the probing strategy does affect the probing delay. Specifically, in the independent sensing scenario, periodic probing indeed achieves the smallest probing delay. In the cooperative sensing scenario, however, randomization can drastically reduce the probing delay.
In this paper pprivacy attacks to ad hoc routing protocols become an important issue as mobile ad hoc networks enter security critical domains. We modified Rids scheme for node location privacy in ANDOR protocol in mobile adhoc network. RIDS scheme also provide facility for the detection of wormhole attack and node misbehaviors in adhoc network. Different author proposed a different scheme for RIDS for providing security in mobile adhoc network. But all technique suffered common problem that problem is generation of node ID and protection of node ID in location based routing protocol. In this dissertation we modified the RIDS model for node id generation technique for identification of location of secured node. For these process we used cyclic shift technique for node ID generation. Here we discuss RIDS ANDOR and describe our proposed scheme.