IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, VOL. 64, NO. 7, JULY 2015 3233 Video-Quality-Driven Resource Allocation for Real-Time Surveillance Video Uplinking Over OFDMA-Based Wireless Networks Po-Han Wu, Chih-Wei Huang, Jenq-Neng Hwang, Fellow, IEEE, Jae-Young Pyun, Member, IEEE, and Juan Zhang Abstract—This paper proposes an effective real-time video up- link (UL) framework for mobile wireless camera networks (WCN) over an orthogonal frequency-division multiple access (OFDMA), based infrastructure. Mobile wireless camera stations (CSs) trans- mit their videos in real time to a base station (BS) so that these live video streams can be archived or fed to subscribers to facilitate real-time video monitoring. Based on the utility function driven by video quality, the target bit rate resulting in the highest pos- sible utility is quickly set for each UL video. To optimize system performance, a real-time video packet scheduler and a spectral- efficient resource-allocation policy are derived. This scheduler is also capable of exploiting the inherent diversity gain due to channel variations. Using fourth-generation (4G) mobile network protocols and a realistic wireless channel model, it is demonstrated through our extensive simulations that our proposed method can significantly enhance utility, boost spectral efficiency, and stabilize video quality. Index Terms—Cross-layer design, Long-Term Evolution (LTE), mobile surveillance system, video quality driven (VQD), video uplink (UL), Worldwide Interoperability for Microwave Access (WiMAX). I. I NTRODUCTION W IRELESS or mobile surveillance systems that integrate wireless cameras or ad hoc wireless video sensor net- works with moving vehicles or mobile devices have become reality [1], [2]. As shown in Fig. 1, video streams captured by wireless or mobile camera stations (CSs) are uploaded via uplink (UL) wireless channels to a control center where the acquired videos can be archived, analyzed, and/or distributed. Surveillance systems of this kind have numerous applica- tions, including real-time traffic monitoring, facility monitor- Manuscript received August 27, 2013; revised March 15, 2014 and June 20, 2014; accepted July 30, 2014. Date of publication August 20, 2014; date of current version July 14, 2015. The review of this paper was coordinated by Dr. L. Zhao. P.-H. Wu is with T-Mobile USA Lab, Bellevue, WA 98006 USA (e-mail: phw2@uw.edu). C.-W. Huang is with the Department of Communication Engineering, Na- tional Central University, Jhongli 32054, Taiwan (e-mail: cwhuang@ce.ncu. edu.tw). J.-N. Hwang is with the Department of Electrical Engineering, University of Washington, Seattle, WA 98105 USA (e-mail: hwang@uw.edu). J.-Y. Pyun is with the Department of Information Communication Engineer- ing, Chosun University, Gwangju 501-759, Korea (e-mail: jypyun@chosun. ac.kr). J. Zhang is with the Shanghai University of Engineering Science, College of Electronic and Electrical Engineering, Shanghai 201620, China (e-mail: zhang-j@foxmail.com). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TVT.2014.2350002 Fig. 1. Real-time video surveillance system over mobile networks. ing, combat/rescue operation monitoring, disaster relief and damage assessment, etc. Depending on specific application scenarios, different quality of service (QoS) requirements may have to be imposed on the design of such systems. For example, video streams that report critical unfolding events will require high QoS levels compared with streams that contain no events. Recent advances in the fourth-generation (4G) wireless broad- band networks, such as IEEE Worldwide Interoperability for Mi- crowave Access (WiMAX) and Third-Generation Partnership Project’s Long-Term Evolution (LTE), have adopted many QoS- enabling technologies such as orthogonal frequency-division multiple access (OFDMA), single-carrier frequency-division multiple access (SC-FDMA), and multi-input–multi-output (MIMO). In particular, OFDMA offers an elegant way of radio resource partition and supports QoS optimization. Many cross-layer (physical (PHY) and medium-access- control layers) QoS-guaranteed scheduling schemes for IEEE 802.16 (WiMAX) systems have been reported [3]–[7]. The method proposed in [3] requires a significant overhead for a low-power mobile station (MS) to upload status information, such as delays of all packets and requirements of bandwidth [7]. Several efficient user/connection-based schemes have sub- sequently been proposed and claimed to be more suitable for UL scheduling [4]–[7]. The proportional fair scheme (PFS) [8] has been widely used in mobile networks with the objective of maximizing the long-term fairness and throughput. How- ever, it has no mechanism to guarantee the QoS for real-time services. Later, an improvement is proposed in [9] that jointly considers PFS, capacity prediction, and video rate adaptation to support the QoS requests of UL videos. Well-known schedul- ing strategies, such as maximum-largest weighted delay first (M-LWDF) and exponential fairness (EXP) [10]–[12], facilitate real-time video streaming by guaranteed minimum throughput and enhanced MS priority scheduling. These existing works 0018-9545 © 2014 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission. See http://www.ieee.org/publications_standards/publications/rights/index.html for more information.