DocumentCode :
61094
Title :
Direct Link-Aware Optimal Relay Selection and a Low Feedback Variant for Underlay CR
Author :
Das, Priyanka ; Mehta, Neelesh B.
Author_Institution :
Dept. of Electr. Commun. Eng. (ECE), Indian Inst. of Sci. (IISc), Bangalore, India
Volume :
63
Issue :
6
fYear :
2015
fDate :
Jun-15
Firstpage :
2044
Lastpage :
2055
Abstract :
Cooperative relaying combined with selection has been extensively studied in the literature to improve the performance of interference-constrained secondary users in underlay cognitive radio (CR). We present a novel symbol error probability (SEP)-optimal amplify-and-forward relay selection rule for an average interference-constrained underlay CR system. A fundamental principle, which is unique to average interference-constrained underlay CR, that the proposed rule brings out is that the choice of the optimal relay is affected not just by the source-to-relay, relay-to-destination, and relay-to-primary receiver links, which are local to the relay, but also by the direct source-to-destination (SD) link, even though it is not local to any relay. We also propose a simpler, practically amenable variant of the optimal rule called the 1-bit rule, which requires just one bit of feedback about the SD link gain to the relays, and incurs a marginal performance loss relative to the optimal rule. We analyze its SEP and develop an insightful asymptotic SEP analysis. The proposed rules markedly outperform several ad hoc SD link-unaware rules proposed in the literature. They also generalize the interference-unconstrained and SD link-unaware optimal rules considered in the literature.
Keywords :
ad hoc networks; amplify and forward communication; cognitive radio; cooperative communication; error statistics; feedback; probability; radio links; radio receivers; radiofrequency interference; relay networks (telecommunication); SD receiver link; SEP; ad hoc SD link-unaware rule; amplify-and-forward relay selection; average interference-constrained underlay CR system; cooperative relaying; direct link-aware optimal relay selection; interference-constrained secondary user; low feedback variant; marginal performance loss; relay-to-destination receiver link; relay-to-primary receiver link; source-to-destination receiver link; source-to-relay receiver link; symbol error probability; underlay cognitive radio; word length 1 bit; Interference constraints; Receivers; Relays; Signal to noise ratio; Silicon; Transmitters; Underlay cognitive radio; amplify-and-forward; amplify-andforward; cooperative communications; feedback; interference constraint; relays; selection; symbol error probability;
fLanguage :
English
Journal_Title :
Communications, IEEE Transactions on
Publisher :
ieee
ISSN :
0090-6778
Type :
jour
DOI :
10.1109/TCOMM.2015.2432026
Filename :
7105886
Link To Document :
بازگشت