Content-aware resource allocation in OFDM systems for energy-efficient video transmission

Demand on multimedia content by consumers' handheld devices over wireless channels is on the increase. In view of the accelerated trend towards consumption of high quality video, power utilization by mobile devices is expected to excessively increase. Hence, it becomes equally important to advance more efficient power minimization techniques, in light of the short battery life in portable devices. However, power minimization algorithms that adopt consumers' perceptual quality of video have not received adequate research. This paper proposes a joint optimization of energy and quality requirements in a multiuser orthogonal frequencydivision multiplexing environment. A multi-objective optimization problem is formulated with the aim to identify bitrate allocations among users such that total power is minimized, and average quality is maximized. For this, a content-aware and energy-efficient resource allocation scheme (CaERAS) is proposed based on genetic and greedy algorithms. Simulation results show that CaERAS, as a lowcomplexity scheme, outperforms comparable methods in terms of efficiency and selectivity of suboptimal solutions. It is shown to acquire a suboptimal solution in as low as 0.0025 of the search space in previous methods. Also, a significant average saving of 85.66% in required energy is observed in broadcast transmission as opposed to unicast transmission.

I. Introduction

The increasingly accelerated consumer demand on multimedia content over mobile and tablet devices has attracted a proportionate interest in the challenges confronting wireless communication systems. One compelling challenge is energy consumption of mobile terminals becoming increasingly displeasing to consumers, especially when high-quality multimedia content is consumed. From the perspective of wireless resource allocation, adaptive subcarrier and bit allocation is addressed by the multicarrier modulation technique orthogonal frequency-division multiplexing (OFDM). Within adaptive subcarrier and bit allocation, researchers have developed several algorithms and techniques aiming at power efficiency [1]–[6]. Some power allocation techniques focused on power minimization solely, whereas others considered content quality as well. However, content quality was mainly assessed by analysis of received signal rather than assessing the perceptual quality as perceived by consumers. Therefore, due to the momentous importance of energy efficiency along with user's content quality perception in mobile consumer devices, this paper focuses on these two problems with an effort to address them jointly in a multiuser OFDM environment.