Energy-efficient resource allocation for OFDMA two-way relay networks with imperfect CSI

Abstract

Most of the existed works on the radio resource allocation (RRA) problem commonly assume the channel-state information (CSI) can be perfectly obtained by the transmission source. However, such assumption is not practical in the realistic wireless systems. In this work, we consider the practical implementation issues of resource allocation in orthogonal frequency division multiple access (OFDMA) two-way relay networks: the inaccuracy of channel-state information (CSI) available to the source. Instead, only the estimated channel status is known by the source. In this context, a joint optimization of subcarrier pairing and allocation, relay selection, and transmit power allocation is formulated in OFDMA two-way amplify-and-forward relay networks. Moreover, the objective of this work is to minimize the energy consumption of the overall system. Further, to ensure the quality of service (QoS) or data rate requirement, the energy consumption must be minimized without compromising the QoS. Therefore, by applying convex optimization techniques, energy-efficient algorithms are developed with the objective to minimize the total transmit power with guaranteeing the required data rates. Through simulation studies, energy consumption performance of the systems under the proposed schemes is investigated. It can be observed that our proposed scheme can improve the energy consumption performance of the considered system.

Robust resource allocation for orthogonal frequency division multiplexing‐based cooperative cognitive radio networks with imperfect channel state information

“…In [15], a distributed power control algorithm with robust protection of PUs is proposed to maximise sum throughput of SUs in a downlink CRN. In [16], a joint optimisation algorithm of subcarrier pairing and allocation, relay selection and transmit power allocation is proposed in OFDMA two-way relay networks with imperfect CSI, where energy consumption minimisation without compromising QoS constraint is the optimisation objective. Moreover, robust resource allocation problems in cooperative CRNs with imperfect CSI have also been investigated [17][18][19][20].…”

Resource allocation in two-way OFDM-based cognitive radio networks with QoE and power consumption guarantees

“…We denote the channel coefficients from S 1 and S 2 to the k th , k ∈ [ 1 : K] relay node on the n th , n ∈ [ 1 : N] subcarrier are h n 1,k and h n 2,k , respectively. Considering channel reciprocity nature, the duplexing period is smaller than channel coherence time, then the channel coefficients from the k th relay node to S 1 and S 2 on the n th subcarrier are the same as h n 1,k and h n 2,k [8]. In this CRN, we adopt PNC-AF protocol, so information exchange can be finished in two time slots.…”

“…According to the difference of signal processing functions at relay nodes, PNC has several sub-protocols, such as decode-and-forward (DF) and amplify-and-forward (AF). Many previous works focus on PNC-AF protocol since it is easily realized in practical systems [7,8]. Therefore, we focus on two-way OFDM-based CRN with PNC-AF protocol in this paper.…”

Power minimization for OFDM modulated two-way amplify-and-forward relay wireless sensor networks

“…The authors of [21] consider a two-way relay network with multiple pairs of source nodes and proposed a joint power and subchannel allocation and active subchannel selection technique maximizing the summation of the information bits per Joule of energy consumed at each terminal pair. The authors of [22] consider an AF two-way relay scenario with multiple relay nodes and CSI errors and proposed a joint implementation algorithm of subcarrier pairing and allocation, relay selection, and transmit power allocation. Moreover, [6][7][8] have expanded the idea of TWR into WSN settings.…”