Energy-Efficient OFDM Radio Resource Allocation Optimization With Computational Awareness: A Survey

Abstract

In this paper, we review radio resource optimization methods for energy-efficient wireless communication in links and networks using the Orthogonal Frequency Division Multiplexing (OFDM) and Orthogonal Frequency Division Multiple Access (OFDMA) techniques. We first consider the energyefficiency metrics and optimization goals. We discuss the increasingly complex systems, starting from (i) a single OFDM link, (ii) an OFDMA single-hop network to (iii) multi-hop relay OFDMA interference networks.In each case, we elaborate on the transmission rate estimation, power consumption modelling, existing optimization constraints and the optimization solutions. Specifically, in the power-consumption modelling, we include the signal-processing (and related computing) power. We discuss the practicality of the considered solutions. We also touch upon the problem of nonlinear power amplifier characteristics (causing distortions typical for OFDM signals) to be taken into account for energy-efficient resource allocation. We discuss trade-offs and provide recommendations for future energy-efficient OFDM networks design. We also discuss the future works and challenges in the context of energy efficiency resource allocation for OFDM/OFDMA and their derivative techniques. We conclude that the presented design practices should include computational awareness in the networks to trade-off between information communication, information processing and the required network management energy-efficiency.

Coded Assisted Transmit and Receive IQ Mismatch Compensation With Channel Estimation for AF Cooperative OFDM Systems

“…is the kth data symbol of the mth OFDM symbol, and j = √ −1. In this sense, − → x = x (0) , x (1) , • • • , x (M−1) † stands for the unaltered transmitted frame where…”

“…(26) According to (23)(24)(25)(26), the exact ML solution necessitates prior knowledge of the transmission matrices X (1) and X (2) , which are typically unavailable. In such situations when nuisance parameters are present, the EM mechanism offers a solution that involves repeated iterations of the search for the ML estimates [29], [30].…”

“…where the expectation is carried out over the matrices X (1) and X (2) . This leads us to a derivation of the Mstep as ĜSD (ι + 1) , ĜSRD (ι + 1) = arg max…”

“…O RTHOGONAL frequency division multiplexing (OFDM) has emerged as the strategy of choice for current and next-generation wireless standards due to its reliability in frequency-selective multipath circumstances and high spectrum efficiency utilization [1], [2]. It has been considered for use in the settings of cellular networks, including the fifth-generation and beyond systems, with its deployment in long term evolution standards [3]- [5].…”

Efficiency Maximization for Battery-Powered OFDM Transmitter via Amplifier Operating Point Adjustment

“…Energy efficiency is typically defined as a ratio of the throughput achieved to the mean power consumption. This metric can obviously be maximized using various degrees of freedom under various constraints [ 13 ]. It is even possible to holistically optimize energy consumption for communications and computing for fog/edge computing applications [ 14 ].…”