Tham Mau-Luen, Chow Chee-Onn, Xu Yi-Han, Ramli Nordin
Department of Electrical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia.
Wireless Innovation, MIMOS Berhad, Technology Park Malaysia, Kuala Lumpur, Malaysia.
PLoS One. 2016 Feb 23;11(2):e0148625. doi: 10.1371/journal.pone.0148625. eCollection 2016.
This paper presents a two-level scheduling scheme for video transmission over downlink orthogonal frequency-division multiple access (OFDMA) networks. It aims to maximize the aggregate quality of the video users subject to the playback delay and resource constraints, by exploiting the multiuser diversity and the video characteristics. The upper level schedules the transmission of video packets among multiple users based on an overall target bit-error-rate (BER), the importance level of packet and resource consumption efficiency factor. Instead, the lower level renders unequal error protection (UEP) in terms of target BER among the scheduled packets by solving a weighted sum distortion minimization problem, where each user weight reflects the total importance level of the packets that has been scheduled for that user. Frequency-selective power is then water-filled over all the assigned subcarriers in order to leverage the potential channel coding gain. Realistic simulation results demonstrate that the proposed scheme significantly outperforms the state-of-the-art scheduling scheme by up to 6.8 dB in terms of peak-signal-to-noise-ratio (PSNR). Further test evaluates the suitability of equal power allocation which is the common assumption in the literature.
本文提出了一种用于下行正交频分多址（OFDMA）网络视频传输的两级调度方案。其目的是通过利用多用户分集和视频特性，在播放延迟和资源约束条件下，使视频用户的总体质量最大化。上层基于总体目标误码率（BER）、数据包重要性级别和资源消耗效率因子，在多个用户之间调度视频数据包的传输。相反，下层通过解决加权和失真最小化问题，在所调度的数据包之间按照目标BER提供不等差错保护（UEP），其中每个用户权重反映了为该用户调度的数据包的总重要性级别。然后，频率选择性功率在所有分配的子载波上进行注水，以利用潜在的信道编码增益。实际仿真结果表明，所提出的方案在峰值信噪比（PSNR）方面比现有调度方案显著高出6.8 dB。进一步的测试评估了文献中常见假设的等功率分配的适用性。
