Low-Complexity Energy-Efficient Scheduling for Uplink OFDMA

Abstract

This is an author produced version of a paper published in IEEE Transactions on Communications.This paper has been peer-reviewed but does not include the final publisher proofcorrections or proceedings pagination.© 2012 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Citation for the published paper: Abstract-Energy-efficient wireless communication is very important for battery-constrained mobile devices. For mobile devices in a cellular system, uplink power consumption dominates the wireless power budget because of RF power requirements for reliable transmission over long distances. Our previous work in this area focused on optimizing energy efficiency by maximizing the instantaneous bits-per-Joule metric through iterative approaches, which resulted in significant energy savings for uplink cellular OFDMA transmissions. In this paper, we develop energy efficient schemes with significantly lower complexity when compared to iterative approaches, by considering time-averaged bits-per-Joule metrics. We consider an uplink OFDMA system where multiple users communicate to a central scheduler over frequency-selective channels with high energy efficiency. The scheduler allocates the system bandwidth among all users to optimize energy efficiency across the whole network. Using timeaveraged metrics, we derive energy optimal techniques in "closed forms" for per-user link adaptation and resource scheduling across users. Simulation results show that the proposed schemes not only have low complexity but also perform close to the globally optimum solutions obtained through exhaustive search.

Flexible Resource Allocation for Joint Optimization of Energy and Spectral Efficiency in OFDMA Multi-Cell Networks

“…This is different from the work [10], which only focus on the power allocation to optimize the EST performance in the single channel scenario. The geometric-mean instead of the arithmetic-mean of all BSs' utilities is considered, in order to make the problem more tractable and to provide the utility fairness amongst multiple cells [4]. Hence, the utility of the entire network is formulated as U = ∑ m∈M log 2 (U m ) and the joint optimization problem of EE and SE in the multi-cell cellular networks can be formulated as follows,…”

Electromagnetic Emission-Aware Scheduling for the Uplink of Multicell OFDM Wireless Systems

“…Thus, in [9], we proposed a user scheduling algorithm to minimize the EM emission of users in the uplink of TDMA, which reduces the EM emission by up to 45% in comparison with traditional TDMA system. In the single cell scenario, subcarrier and power allocation in the uplink of OFDM systems have been very well investigated but mainly for SE improvement [10], [11] and, recently, EE [12], [13]. In the context of EM emission reduction, in [14], we proposed a scheduler for the uplink of OFDM systems to minimize EM emissions and maintain QoS, based on the assumption that the channel state information (CSI) of all the users can be predicted over a certain transmission window (i.e., spanning several time slots).…”

Energy-efficient Scheduling for the Real-time Multicast and Unicast Traffic in MBSFN

“…The constraint problems in the battery of the mobile terminal equipment are mainly concentrated in the wireless communications. [8] takes into account the low complexity of the energy-efficient uplink OFDMA transmission in cellular networks. The energy-efficient scheduling in uplink OFDMA systems [9] takes into account the fairness of resource allocation.…”