Limmanee, Athipat and Dey, Subhrakanti and Nekouei, Ehsan (2014) Optimal power policies and throughput scaling analyses in fading cognitive broadcast channels with primary outage probability constraint. EURASIP Journal on Wireless Communications and Networking, 35. ISSN 1687-1499

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Abstract

This paper focuses on a spectrum-sharing-based fading cognitive radio broadcast channel (BC) with a single-antenna secondary base station (SBS) and M single-antenna secondary receivers (SRs) utilizing the same spectrum band with a delay-sensitive primary user (PU). The service-quality requirement for the primary user is set by an outage probability constraint (POC). We address the optimal power allocation problem for the SBS ergodic sum capacity (ESC) maximization in the secondary BC network subject to POC and a transmit power constraint at SBS specified by either a long-term or a short-term power constraint. The optimality conditions reveal that in each joint channel state, the SBS allocates transmission power to the only one selected SR with the highest value of a certain metric consisting of the ratio of the SR’s direct channel power gain and the sum of interference power and noise power at the SR. Then, the secondary network throughput scaling analysis as the number of SRs becomes large, is also investigated, showing that if PU applies a truncated channel inversion (TCI) power policy, the SBS ESC scales like p log(log M) where p is the PU outage probability threshold. To reduce the amount of channel side information (CSI) transferred between the two networks, we propose a suboptimal transmission scheme which requires only 1-bit feedback from the delay-sensitive PR (partial CSI). We show that the new power control policy is asymptotically optimal, i.e. the SBS ESC under this reduced feedback scheme still scales like p log(log M).

Item Type:	Article
Keywords:	Cognitive radio; Power control; Ergodic capacity; Outage probability; Throughput scaling; Fading broadcast channels;
Academic Unit:	Faculty of Science and Engineering > Electronic Engineering
Item ID:	14425
Identification Number:	https://doi.org/10.1186/1687-1499-2014-35
Depositing User:	Subhrakanti Dey
Date Deposited:	11 May 2021 15:21
Journal or Publication Title:	EURASIP Journal on Wireless Communications and Networking
Publisher:	Hindawi Publishing Corporation
Refereed:	Yes
URI:	Publisher
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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