Routing for cognitive radio networks consisting of opportunistic links

Abstract

Cognitive radio (CR) has been considered a key technology to enhance overall spectrum utilization by opportunistic transmissions in CR transmitter-receiver link(s). However, CRs must form a cognitive radio network (CRN) so that the messages can be forwarded from source to destination, on top of a number of opportunistic links from co-existing multi-radio systems. Unfortunately, appropriate routing in CRN of coexisting multi-radio systems remains an open problem. We explore the fundamental behaviors of CR links to conclude three major challenges, and thus decompose general CRN into cognitive radio relay network (CRRN), CR uplink relay network, CR downlink relay network, and tunneling (or core) network. Due to extremely dynamic nature of CR links, traditional routing to maintain end-to-end routing table for ad hoc networks is not feasible. We locally build up one-step forward table at each CR to proceed based on spectrum sensing to determine trend of paths from source to destination, while primary systems (PSs) follow original ways to forward packets like tunneling. From simulations over ad hoc with infrastructure network topology and random network topology, we demonstrate such simple routing concept known as CRN local on-demand (CLOD) routing to be realistic at reasonable routing delay to route packets through.primary system (PS) [1], has been considered as a key technology toward future wireless communications to enhance spectrum utilization efficiency. The CR concept can be generalized to cooperative co-existing multi-radio systems if the terminal devices are ROUTING FOR CRN 457 Control of CRN Flow Control of CRNFlow control can happen in two types in CRN: First of all, end-to-end flow control between CR source node and CR destination node, while a typical credit-based flow control such as leaky-bucket can does the work. However, for completely successful operation of CRN on-demand routing protocols, such as CRN-ODV or CRN-DSR, we need another function, flow control in CRN network layer. Different from conventional firsttype flow control in computer networks, flow control

Primary weight measure and its support in stochastic routing for dynamic cognitive radio networks

“…Protocols such as LCBR [3], CODV [12], OSDRP [4] and [13] adopt the framework of ad hoc or wireless sensor networks to overcome the unpredictable behavior of primary users. The channels stability is mapped into nodes availability in these protocols.…”

5G Based on Cognitive Radio

“…CR routing research field [8] is based mostly on the CR requirement to interoperate with different systems, and is strongly influenced by the spectrum sharing techniques.…”

A novel solution to routing in Cognitive Radio ad-hoc networks in high primary user traffic environments

“…In [10] a Common Link Control Radio(CLCR) is introduced for neighbor discovery and routing in networks where spectrum sensing is performed in a distributed fashion.The CLCR is used to find a path from source to destination such that the transmitted power is minimum.In [11] ding et al have proposed a new algorithm ROSA where each node choses the next hop to maximize spectrum utility [12] and the process is repeated till the destination is reached.Pefkianakis et al have proposed SAMER [13] which tries to balance between long term route stability and short term performance via building a runtime forwarding mesh and the actual forwarding path is determined by the current spectral conditions at the node.In [14] Opportunistic Cognitive Routing (OCR) protocol is proposed where the trasmission performance over a single hop is improved by allowing the users to use location information in finding local spectrum access opportunities.In [15] a one step routing table is established at each node based on the history of channels instead of an end-to-end routing table which is not feasible due to the dynamic nature of CR links.In [16] a new metric that considers the maintenance cost of routes as the number of channels or routes that have to be switched in the presence of PU traffic is introduced and routes are categorized based on this metric.…”