Open AccessImpact of access contention on cooperative sensing optimisation in cognitive radio networks
Author(s) -
Zhang Shaojie,
Zhao Haitao,
Wang Shan,
Hafid Abdelhakim Senhaji
Publication year - 2017
Publication title -
iet communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.355
H-Index - 62
eISSN - 1751-8636
pISSN - 1751-8628
DOI - 10.1049/iet-com.2016.0593
Subject(s) - cognitive radio , aloha , computer science , interference (communication) , throughput , transmission (telecommunications) , physical layer , signal to noise ratio (imaging) , phy , key (lock) , computer network , algorithm , channel (broadcasting) , wireless , telecommunications , computer security
The tradeoff between decreasing interference to primary user (PU) and increasing secondary user's (SU's) throughput is of great importance for cooperative sensing in cognitive radio networks. Non‐ideal spectrum sensing in PHY and multiple SUs' access contention in MAC jointly impact SUs' transmission and the tradeoff. In this study, the authors investigate the joint impact from a cross‐layer perspective. First, they quantify the reliability of cooperative sensing and compute SUs' transmission probability under the conditions of non‐ideal sensing and access contention. Closed‐form expressions of the interference probability to PU and SUs' throughput are derived. Specially, two widely‐used contention‐based MAC protocols, i.e. slotted Aloha and distributed coordination function, are studied. Then, they formulate the sensing‐throughput tradeoff problem by using interference probability to PU, rather than the detection probability, as the constraint. Finally, a 2‐dimension search algorithm is proposed to obtain the optimal solution, including the optimal fusion rule, sensing duration and detection threshold. Simulation results validate the outperformance of the cross‐layer scheme. They also demonstrate how the optimal solution varies with some key parameters, i.e. PU's signal‐to‐noise ratio and the number of contending SUs.