Resource allocation for energy efficient cellular systems

Abstract

The need for more throughput in wireless cellular networks has been increasing in recent years. It has led to an increase in operational costs due to higher energy use as operators deploy more cell sites or increase transmission power at existing ones to satisfy demand. Energy costs are a major expense, and reducing them is a priority. This article presents a scheduler which aims to solve the problem of energy efficient resource allocation in orthogonal frequency division multiple access (OFDMA) cellular systems. The suggested approach is to make the resource scheduling process also consider energy costs as well as allow it to manipulate these by exploiting time/frequency vs energy efficiency trade-offs that are present in the system. The energy efficient score-based scheduler (EESBS) is a novel scheduler which takes energy costs into account when allocating resource blocks (RBs) to users. This allows it to promote energy efficiency in the system alongside throughput and fairness maximization. One of the means it has to manipulate users' expended energy is the bandwidth expanded mode (BEM). BEM is a technique that allows the scheduler to decrease a user's energy consumption by allocating it more RBs and maintaining a constant data rate. This is possible when the energy consumption is dominated by the energy used for data communication as opposed to control channel overhead transmission. Time compression mode (TCoM) is a technique that is complementary to BEM. It allows for energy savings through a reduction of the number of allocated RBs to a user when the energy consumption is dominated by the transmission of signaling traffic. Both BEM and TCoM need to be employed by an energy-aware scheduler like EESBS in order to extract the maximum performance gains. A realistic framework modeling future cellular systems is established to test the performance of the proposed techniques. Within this framework, EESBS generates an average energy saving of 29% over a frequency selective proportional fair (FsPF) benchmark. EESBS coupled with BEM or TCoM achieves a saving of 38% over the same benchmark. These savings are achieved with no detriment to user satisfaction in terms of achieved data rate.

A Survey on Green Mobile Networking: From The Perspectives of Network Operators and Mobile Users

“…The majority of research works that investigate green communication solutions at a high traffic load employ static traffic models for resource scheduling and performance evaluation, as in [9], [23], [33], [34], [43], [49], [50], [77], [78], [82], [86], and [88]. Very few works use traffic models that reflect long-term (as in [79] and [87]) or short-term (as in [54], [56], and [57] for call-level and [59] for packet-level) temporal fluctuations.…”

“…An approach to implement the margin adaptive strategy is via a scorebased scheduler. For instance, in an OFDMA system, the BS calculates a score for every resource block q to be assigned to MT m [77]. The calculated score ensures that the BS would consume the least transmission power by assigning resource block q to MT m. Moreover, the score promotes fair resource allocation among MTs, as a penalty function can be included based on the number of already allocated resource blocks for MT m. A low score indicates a more desirable resource block.…”

“…[9], [54], [77] - [81] User association in Heterogeneous wireless medium It assigns the MTs to the BSs, with coverage overlap, that reduce energy consumption for a set of operators.…”

Energy Efficiency Tradeoff Mechanism Towards Wireless Green Communication: A Survey

“…Such a process is relatively complex in cellular infrastructures since mobility and user activity patterns may create load fluctuations [143], [144]. Authors in [145] introduces energy-aware network re-configuration methods to flexibly load variations encouraging none or minimal extra energy consumption.…”

Impact of service rates and base station switching granularity on energy consumption of cellular networks

“…Authors emphasize that cell zooming, besides solving the problem of traffic imbalance, can also reduce energy consumption of the cellular network. Due to the need for more throughputs in wireless cellular networks, Videv et al [24] develop a scheduler which aims to solve the problem of energy-efficient resource allocation in orthogonal frequency division multiple access cellular systems. Huang et al [25] propose energy-efficient semistatic power control and a link adaptation scheme for UMTS (HSDPA) networks.…”