Pragmatic Distributed Algorithm for Spectral Access in Cooperative Cognitive Radio Networks

Abstract

Abstract-A pragmatic distributed algorithm (PDA) is proposed for supporting the efficient spectral access of multiple Primary Users (PUs) and Cognitive Users (CUs) in cooperative Cognitive Radio (CR) networks. The novelty of our PDA is that the PUs negotiate with the CUs concerning the specific amount of relaying and transmission time, the CU is granted, which the CU will either accept or decline. The CUs may serve as relay nodes for relaying the signal received from the PUs to their destinations, while both the PUs' and the CUs' minimum rate requirements are satisfied. This will reduce the required transmission power and/or increase the transmission rate of the PU. Our results show that the proposed scheme performs better than the benchmarker, despite its significantly lower overhead and complexity. Moreover, we show that the cooperative spectral access based on our PDA reaches an equilibrium, when it is repeated for a sufficiently long duration. These benefits are achieved, because the PUs are motivated to cooperate by the incentive of achieving a higher PU rate, whilst non-cooperation can be discouraged with the aid of a limited-duration punishment. Furthermore, we invoke an attractive practical adaptive Turbo Trellis Coded Modulation (ATTCM) scheme, which appropriately adjusts the code rate and the modulation mode according to the near-instantaneous channel conditions. It was found that the joint design of coding, modulation and user-cooperation may lead to significant mutual benefits for all the PUs and the CUs.Index Terms-Cognitive radio network, cooperative communication, spectrum access strategy, matching algorithm, ATTCM.

Distributed Matching Algorithms: Maximizing Secrecy in the Presence of Untrusted Relay

“…PDA was proposed in [22] also for maximizing the sumrate for the PU. PDA was better than CDA in terms of the PU sum-rate as it catered for the losses endured by the CDA due to competing primary nodes for acquiring the best SU in terms of secrecy maximization obtained in Sec.…”

“…al. in [22] also provide results for Adaptive Turbo Trellis Coded Modulation (ATTCM) for her algorithm showing the practicality of the algorithm. For our system we also use PDA based cooperative jamming and compare it with CDA based cooperative jamming using idealistic situation where the system can operate at the capacity of the Continuous-Input Continuous-Output Memoryless Channel (CCMC) and that of the Discrete-Input Continuous-Output Memoryless Channel (DCMC) [23].…”

“…The downside of the CDA was that the Primary Users (PU) which in this case are S compete among themselves for matching with the best possible Secondary User (SU) which is the CJ. Another matching algorithm called Pragmatic Distributed Algorithm (PDA) was presented in [22] where this competition was eliminated by introducing another game where the PUs participate in a round robin rotation manner for acquiring the best possible SU/CJ. In that way each of the PUs will gain access to its best possible SU for at least one round.…”

“…We show results for the two cases i.e., with and without the direct link between the source and destination1. Secondly we provide a secrecy maximization framework where we considered the following cooperative distributed matching algorithms which are based on the adaptation of the PDA and CDA of [22]:…”

Performance of Cognitive Hybrid Automatic Repeat reQuest: Go-Back-N

“…In [14,15], the authors analyzed the delay of GBN-ARQ, while both the average packet delay and its distribution have been studied in [16]. A hybrid of the interweave and underlay paradigms has been proposed in [18,19] for improving the performance of CRU. The authors of [19] have also used the ARQ approach for improving the reliability.…”