Limited-Feedback-Based Adaptive Power Allocation and Subcarrier Pairing for OFDM DF Relay Networks With Diversity

Abstract

A limited feedback based dynamic resource allocation algorithm is proposed for a relay cooperative network with Orthogonal Frequency Division Multiplexing (OFDM) modulation. A communication model where one source node communicates with one destination node assisted by one halfduplex Decode-and-Foward (DF) relay is considered in this paper. We first consider the selective DF scheme, in which some relay subcarriers will keep idle if they are not advantageous to forward the received symbols. Furthermore, we consider the enhanced DF scheme where the idle subcarriers are used to transmit new messages at the source. We aim to maximize the system instantaneous rate by jointly optimizing power allocation and subcarrier pairing on each subcarrier based on the Lloyd algorithm. Both sum and individual power constraints are considered. The joint optimization turns out to be a mixed integer programming problem. We then transform it into a convex optimization by continuous relaxation, and achieve the solution in the dual domain. The performance of the proposed joint resource allocation algorithm is verified by simulations. We find that the proposed scheme outperforms the existing methods in various channel conditions. We also observe that only a few feedback bits can achieve most of the performance gain of the perfect CSI based resource allocation algorithm at different levels of SNR.

Linear Processing Design of Amplify-and-Forward Relays for Maximizing the System Throughput

“…References [8][9][10][11] consider the scenario with one BS, one relay and one user. Reference [8] jointly optimizes the subcarrier pairing and power allocation, and a mixed-integer programming problem is formulated.…”

“…Reference [8] jointly optimizes the subcarrier pairing and power allocation, and a mixed-integer programming problem is formulated. Then, the authors in [8] transform the mixed integer programming problem into a convex optimization through continuous relaxation.…”

“…Reference [8] jointly optimizes the subcarrier pairing and power allocation, and a mixed-integer programming problem is formulated. Then, the authors in [8] transform the mixed integer programming problem into a convex optimization through continuous relaxation. [9] proposes a hybrid scheme in which the full-duplex and halfduplex relaying modes can be switched opportunistically to obtain a tradeoff between spectral efficiency and selfinterference.…”

Uplink radio resource allocation in orthogonal frequency‐division multiple access heterogeneous networks with limited feedback

“…In [12], a suboptimal and iterative algorithm has been developed for finding the CQI quantiser as well as discrete power and rate employed in cognitive networks. In [13], a limited feedback model for a single link assisted by one RS is investigated. In [14], the limited feedback scheme has been proposed for a single cell relay assisted cognitive network.…”

Joint Subcarrier Pairing and Power Allocation in OFDMA Cooperative Relay Networks

“…Capacity and throughput can also be enhanced through cooperative resource sharing and scheduling among nodes within a network. At present, the joint subcarrier and power allocation problem is often formulated as an optimization problem of maximizing the system throughput or the weighted sum rate under the total sum power constraint and the individual power constraint, respectively [6], [7], [8], [9], [10], [11], [12]. The proposed strategies are based on nonlinear programming and the Lagrangian dual decomposition method.…”