Joint Subcarrier and Power Allocation Methods in Wireless Powered Communication Network for OFDM systems

TL;DR

This paper proposes joint subcarrier and power allocation methods for OFDM-based wireless powered communication networks, addressing both perfect and imperfect self-interference cancellation scenarios to maximize sum-rate.

Contribution

It introduces efficient algorithms for joint subcarrier and power allocation in full-duplex H-AP systems considering residual self-interference, improving performance over conventional schemes.

Findings

Proposed algorithm for perfect SIC achieves near-optimal sum-rate.

Iterative algorithm for imperfect SIC significantly outperforms conventional methods.

Methods effectively handle non-convex optimization problems in wireless powered communication.

Abstract

In this paper, we investigate wireless powered communication network for OFDM systems, where a hybrid access point (H-AP) broadcasts energy signals to users in the downlink, and the users transmit information signals to the H-AP in the uplink based on an orthogonal frequency division multiple access scheme. We consider a fullduplex H-AP which simultaneously transmits energy signals and receives information signals. In this scenario, we address a joint subcarrier scheduling and power allocation problem to maximize the sum-rate under two cases: perfect self-interference cancelation (SIC) where the H-AP fully eliminates its self interference (SI) and imperfect SIC where the residual SI exist. In general, the problems for both cases are non-convex due to the subcarrier scheduling, and thus it requires an exhaustive search method, which is prohibitively complicated to obtain the globally optimal solution. In order to reduce the complexity, for the perfect SIC scenario, we jointly optimize subcarrier scheduling and power allocation by applying the Lagrange duality method. Next, for the imperfect SIC case, the problem is more complicated due to the SI at the H-AP. To solve the problem, we propose an iterative algorithm based on the projected gradient method. Simulation results show that the proposed algorithm for the case of perfect SIC exhibits only negligible sum-rate performance loss compared to the optimal algorithm, and the proposed iterative algorithm for the imperfect SIC case offers a significant performance gain over conventional schemes.