Energy efficiency analysis of hybrid-ARQ relay-assisted schemes in LTE-based systems

Abstract

This work deals with the analysis of energy efficiency (EE) issues of hybrid automatic repeat request (HARQ) protocols such as Chase combining (CC) and incremental redundancy (IR), in a LTE baseband-based half-division duplex relay-assisted network. The EE performance is highly dependent on delay and circuitry power consumption, i.e., baseband and radio-frequency (RF) parts, and the effects of these components are investigated for amplify and forward (AF) and decode and forward (DF) protocols. Moreover, a realistic estimation of the baseband power consumption is provided. Our contributions in this paper can be summarized as follows: (1) an accurate estimation of power consumption of the main blocks of the LTE baseband is provided based on a real field-programmable gate array (FPGA) target and is integrated to a global energy consumption model (2) based on the previous power consumption evaluation; energy-efficiencies of DF protocol with HARQ-CC and HARQ-IR are investigated with various modulation orders; in addition, a quite insightful study of the energy efficiency-spectral efficiency trade-off is conducted, and (3) DF and AF protocols with HARQ are compared in terms of EE, and recommendations are suggested in order to jointly enhance the QoS and the energy efficiency of wireless systems.

Energy Efficient Resource Allocation for Type-I HARQ Under the Rician Channel

“…where x * (λ) is given by (21). Since g (x) is strictly increasing, x * (λ) is also increasing, implying that γ * (λ) is strictly decreasing due to (23). To find λ * , we use the complementary slackness condition (18).…”

Energy Minimization in HARQ-I Relay-Assisted Networks With Delay-Limited Users

“…In order to overcome the difficulty implied by this non linear problem, we consider that the delays N respectively. Hence, the energy minimization problem under average delay and power constraints can be formulated as in (16). One can notice that problem (12) is equivalent to (16) by just substituting the equality constraints (c 3 ), (c 4 ) and (c 5 ) in the objective function (16).…”

“…In our previous works [15], [16], EE in relay-assisted HARQ scheme have been analyzed in a single user context without considering any resource optimization problem. In particular in [16], we have been interested in the EE analysis for HARQ schemes in single user source-relay-destination framework, when a practical FPGA target is considered. However, no resource allocation problems for optimizing throughput and/or power have been formulated nor solved.…”

Asymptotic Analysis of Area Spectral Efficiency and Energy Efficiency in PPP Networks With SLNR Precoder

“…However, the static power consumption is not taken into account in these works. Since the BS static power consumption cannot be neglected, the tradeoff between EE and SE considering a practical power consumption model has been a growing subject of interest in recent years [4]- [8].…”