Open AccessOptimal beamforming in spectrum sharing cognitive non‐regenerative multi‐relay networks
Author(s) -
Feng R.,
Li Q.,
Zhang Q.,
Qin J.
Publication year - 2013
Publication title -
electronics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.375
H-Index - 146
eISSN - 1350-911X
pISSN - 0013-5194
DOI - 10.1049/el.2013.1725
Subject(s) - beamforming , relay , computer science , cognitive radio , computer network , electronic engineering , telecommunications , engineering , wireless , physics , power (physics) , quantum mechanics
An optimal beamforming design for spectrum sharing cognitive non‐regenerative multi‐relay networks that maximises the signal‐to‐noise ratio of the secondary user subject to the total transmit power constraint at the relays and the interference power constraint at the primary user is proposed. In the power‐limited regime and the interference‐limited regime, closed‐form beamformers can be found. While in the intermediate operating regime, the beamforming problem is first transformed to a convex semidefinite programming (SDP) via rank‐one relaxation and Charnes‐Cooper transformation, and then the optimal beamformers are found by applying the rank‐one decomposition theorem to the solution of the established SDP. Simulation results show that the proposed solution performs better than existing schemes.