H2-ARQ-Relaying: Spectrum and Energy Efficiency Perspectives

Abstract

Abstract-In this paper, we propose novel Hybrid Automatic Repeat re-Quest (HARQ) strategies used in conjunction with hybrid relaying schemes, named as H 2 -ARQ-Relaying. The strategies allow the relay to dynamically switch between amplify-andforward/compress-and-forward and decode-and-forward schemes according to its decoding status. The performance analysis is conducted from both the spectrum and energy efficiency perspectives. The spectrum efficiency of the proposed strategies, in terms of the maximum throughput, is significantly improved compared with their non-hybrid counterparts under the same constraints. The consumed energy per bit is optimized by manipulating the node activation time, the transmission energy and the power allocation between the source and the relay. The circuitry energy consumption of all involved nodes is taken into consideration. Numerical results shed light on how and when the energy efficiency can be improved in cooperative HARQ. For instance, cooperative HARQ is shown to be energy efficient in long distance transmission only. Furthermore, we consider the fact that the compress-and-forward scheme requires instantaneous signal to noise ratios of all three constituent links. However, this requirement can be impractical in some cases. In this regard, we introduce an improved strategy where only partial and affordable channel state information feedback is needed.

Cross-Layer Design and Optimization for Green Wireless Communications and Networking

“…Following the same line of argument, the average air time and energy expenditure can also be derived for other four cases. For the purpose of conciseness, their expressions are not shown in this book but readers can refer to [12] for details.…”

Energy efficiency of some non-cooperative, cooperative and hybrid communication schemes in multi-relay WSNs

“…However, spectral efficiency compensations in order to obtain the same end-to-end throughput are not imposed to the CT scheme. In [23] the energy efficiency of some hybrid relaying schemes, including AF/DF and CF/DF is analyzed under the constraint of a target outage probability. The proposed relaying strategy is able to obtain either transmit or receive diversity.…”

On the Energy Efficiency of Hybrid Relaying Schemes in the Two-Way Relay Channel

“…In the final phase, R broadcasts to S 1 and S 2 . Each phase lasts for T/3 seconds, where T is the activation time and subject to the constraint [7]. Similarly, the signal received during phase 2 are given by …”

“…While the optimal relaying strategy in wireless networks has not yet been fully understood, several relaying schemes have been suggested in the literature including amplify-and-forward (AF), decode-andforward (DF) and compress-and-forward (CF) [5,6]. More recently, advanced hybrid relaying schemes have been proposed and analyzed from both spectrum and energy efficiency perspectives [7]. However, these works are focused on one way relay where the communication is in one direction only, i.e.…”