Research Article
Optimal Power Allocation for OFDM-Based Wire-Tap Channels with Arbitrarily Distributed Inputs
@INPROCEEDINGS{10.1007/978-3-642-30493-4_20, author={Haohao Qin and Yin Sun and Xiang Chen and Ming Zhao and Jing Wang}, title={Optimal Power Allocation for OFDM-Based Wire-Tap Channels with Arbitrarily Distributed Inputs}, proceedings={Wireless Internet. 6th International ICST Conference, WICON 2011, Xi’an, China, October 19-21, 2011, Revised Selected Papers}, proceedings_a={WICON}, year={2012}, month={10}, keywords={OFDM wire-tap channel arbitrarily distributed inputs duality theory nonconvex problem optimal power allocation}, doi={10.1007/978-3-642-30493-4_20} }- Haohao Qin
Yin Sun
Xiang Chen
Ming Zhao
Jing Wang
Year: 2012
Optimal Power Allocation for OFDM-Based Wire-Tap Channels with Arbitrarily Distributed Inputs
WICON
Springer
DOI: 10.1007/978-3-642-30493-4_20
Abstract
In this paper, optimal power allocation is investigated for maximizing the secrecy rate of orthogonal frequency division multiplexing (OFDM) systems under arbitrarily distributed input signals. Considering the discrete inputs are used in practical systems rather than the commonly assumed Gaussian inputs, we focus on secrecy rate maximization under more practical finite discrete constellations in this paper. It is known that the secrecy rate achieved by Guassian distributed inputs is concave with respect to the transmission power. However, we prove that the secrecy rate of finite discrete constellations is non-concave, which makes traditional convex optimization methods not applicable to our problem. To address this non-concave power allocation problem, we propose an efficient power allocation algorithm. Its gap from optimality vanishes asymptotically at the rate , and its complexity grows in order of (), where is the number of sub-carriers. Numerical results are provided to illustrate the benefits and significance of the proposed algorithm.
