Energy‐efficiency maximisation for cooperative and non‐cooperative OFDMA cellular networks—a survey

Abstract

In this survey, techniques to enhance energy efficiency (EE) in orthogonal frequency division multiple access (OFDMA) and orthogonal frequency division multiplexing (OFDM) systems, with or without the utilisation of the cooperative network paradigm, considering also the features provided in the standards of modern cellular wireless networks, such as LTE-Advanced and WiMAX, are discussed. For the non-cooperative EE maximisation case, we summarise resource allocation problems and also describe some techniques that can be combined with the basic power/subcarrier allocation problems. When considering the cooperative OFDM(A) case, we first discuss four basic variables that arise with the relay station implantation, and after that, other features are also listed, which can be combined with the previously discussed issues. Finally, we review some of the standardisation documents available for fourth-generation systems in order to obtain system parameters and simulation scenarios, discuss some methods to analyse and solve the optimisation problems that can be proposed with the aforementioned techniques and then point out important open trends and research challenges in the EE maximisation problem considering OFDM(A) scenario.

Stochastic geometry model to analyze 5G energy efficiency based on a novel dynamic spectrum access scheme

“…Let us denote the EE, defined by the ratio between the area's spectral network and the average network power consumption, as Θ E E , given by where the area spectral efficiency is defined as the sum of the average throughput for all the users (MUE and SUE) and the average network power consumption representing the total consumption power P T jointly supported by the MBS and the SCS. To derive the analytical EE expression, the total network throughput has to be defined, and the total power consumption P T has to be calculated.…”

Game theoretic frequency reuse approach in OFDMA femtocell networks

“…There are many importance on the deployment of femtocells in regard to the frequency reuse for mitigating the interferences between the different tiers so as to enhance the network performance . An OFDMA (both Long‐Term Evolution and WiMAX) is the great amount of dynamically assigned time and frequency slots . This significant growth in the modulability of resource allotment is both an advantage and a drawback.…”

“…7 An OFDMA (both Long-Term Evolution and WiMAX) is the great amount of dynamically assigned time and frequency slots. 8,9 This significant growth in the modulability of resource allotment is both an advantage and a drawback. As orthogonal resources are possible to assign to nearby pico and macrocells by femtocells, hence the feasibility of fine-tuned interference management (IM) prevails, which is nonfeasible in case of global system for mobile communications or code division multiple access.…”

A novel low complexity energy‐efficient resource allocation for OFDM systems

“…Conventionally, EE was defined as 'information bits per unit of transmit energy', however, practical concerns cause to take into account circuit energy consumption into the energy consumption model and redefine the EE metric as 'information bits per unit of consumed energy (not only transmit energy but also circuit power energy)' where an additional circuit power (CP) factor needs to be considered [2,3]. It is shown in [4] that the transceiver power consumed in 802.11x in idle mode is comparable with the transmit mode.…”