Modern mobile devices, such as laptops, PDAs (Personal Digital Assistants), smart phones, and PMPs (Portable Media Players), have evolved to powerful mobile computers and can render rich multimedia content. Increasingly more users use mobile devices to watch videos streamed over wireless networks, and they demand more content at better quality. For example, market forecasts reveal that mobile video streaming, such as mobile TV, will catch up with gaming and music, and become the most popular application on mobile devices: more than 140 million subscribers worldwide by 2011. In this tutorial, we will present different approaches to deliver multimedia content over various wireless networks to many mobile users. We will study and analyze the main research problems in modern wireless networks that need to be addressed in order to enable efficient mobile multimedia services. The tutorial will cover common research problems in wireless networks such as HSDPA (High-Speed Downlink Packet Access), MBMS (Multimedia Broadcast Multicast Services) extension of cellular networks, WiMAX (Worldwide Interoperability for Microwave Access), LTE (Long Term Evolution), DVB-H (Digital Video Broadcasting – Handheld), and ATSC M/H (Advanced Television Systems Committee – Mobile/ Handheld). After giving the preliminaries of the considered wireless network standards, we will focus on several important research problems and present their solutions in details. These research problems include: (i) maximizing energy saving of mobile receivers, (ii) maximizing bandwidth utilization of wireless networks, (iii) minimizing stream switching time, and (iv) supporting heterogeneous mobile receivers. Finally, we will discuss open problems and future research directions in mobile multimedia.
Course outline
This tutorial consists of five parts. We first give a high-level overview on mobile video streaming systems, and present the leading-edge wireless networks. We then present the challenges in designing and implementing mobile video streaming systems. This is followed by discussion on concrete research problems and recently proposed solutions for them. We next discuss open research problems, and conclude the tutorial with outlook.
Introduction
We present a simple model for mobile video streaming systems, which abstracts away the common components to enable efficient mobile video streaming. We then specialize this model to several modern wireless networks, including HSDPA, MBMS extension of cellular networks, WiMAX, LTE, DVB-H, MediaFLO, and ATSC M/H. We then present the advantages/disadvantages of mobile video streaming over each of the considered wireless networks. Our comparison concentrates on their architectures, protocols, operation, deployment cost, and future potential. Our comprehensive comparison allows audience to understand the merits of individual wireless networks, and enables them to pick the wireless network that is most suitable to their needs. More importantly, our introduction clearly identifies the common components of all wireless networks. This enables general discussions on challenges and solutions in the rest of our tutorial, which can be readily applied to various wireless networks.
Challenges
We first discuss general challenges in multimedia wireless networks. For example, mobile video streaming systems need to cope with high error rates in wireless networks, because wireless channels are vulnerable to noise, fading, shadowing, and interference. In addition, some wireless networks deploy smaller cells to enable frequency reuse for higher spectrum efficiency. In these wireless networks, mobile video streaming systems must consider mobility and handoffs for mobile users to roam among cells. We also present challenges on providing good video streaming Quality-of-Experience (QoE) in mobile video streaming systems. The considered challenges can be classified into two groups: (i) user perspective and (ii) service provider perspective. User perspective challenges include optimizing streaming quality, energy saving, channel switching delay, and supporting heterogeneity. Streaming quality refers to smooth video playout on all mobile devices, which is only possible if video data are delivered on time without overflowing receiving buffer on mobile devices. Energy saving refers to how much time each mobile device can turn off its receiving circuit in order to conserve energy and prolong watch time. Channel switching delay is the time that a user waits before s/he starts viewing a selected video stream when a change of video stream is requested by that user. Supporting heterogeneity means allowing mobile users to watch the same video channels using mobile devices with heterogeneous resources, such as screen resolution, decoder capability, and battery level. Provider perspective problems include bandwidth efficiency and implementation complexity. Bandwidth efficiency refers to the number of video streams that can be concurrently streamed at a quality no worse than a given target quality within a bandwidth limitation. Implementation complexity considers the efforts to implement video encoders, transcoders, burst transmission schedulers, base stations, and network planning and deployment.
Problems and Recent Research Advances
We next discuss concrete research problems and present recently proposed solutions to them. These will include:
- Maximizing energy saving of mobile receivers
- Maximizing bandwidth utilization of wireless networks
- Minimizing stream switching time
- Supporting heterogeneous mobile receivers.
Open Research Problems
Several issues of mobile video streaming systems have not yet been rigorously studied. We will present these open problems. For example, we briefly describe an open problem of designing a hybrid streaming network in the following, while more open problems will be discussed in the tutorial. To minimize bandwidth requirements, depending on the number of receivers for individual videos, some videos may better be broadcast, while others may be more suitable to be unicast. For illustration, consider a video stream requested by a single mobile user, devoting a channel in broadcast networks to it may not be bandwidth efficient. In such scenario, streaming using unicast networks is more efficient. Therefore, hybrid unicast-broadcast networks lead to better bandwidth efficiency. Several works in the literature investigate the potential benefits of building such hybrid networks. However, several design challenges in such hybrid networks remain open.
Conclusions and Outlook
We will summarize our tutorial and review the most important take-aways. Moreover, we will give service providers some guidelines on choosing the wireless networks that are suitable to them. We believe our tutorial will largely simplify the future design and implementation of mobile video streams over modern wireless networks.
Audience
The tutorial discusses challenges and solutions in cutting-edge wireless networks and will attract both R&D engineers and academic scholars. This is a self-contained tutorial targeting intermediate and advanced audience. It will be of interest to researchers, graduate students, and engineers interested in video streaming to mobile devices.
Organizers/Presenters
Mohamed Hefeeda received the Ph.D. degree from Purdue University, West Lafayette, IN, USA in 2004, and the M.Sc. and B.Sc. degrees from Mansoura University, Egypt in 1997 and 1994, respectively. He is an assistant professor in the School of Computing Science, Simon Fraser University, Surrey, BC, Canada, where he leads the Network Systems Lab. His research interests include multimedia networking over wired and wireless networks, peer-to-peer systems, network security, and wireless sensor networks. He has co-authored more than 60 publications in reputable journals and conferences in the past five years, many of them on multimedia streaming to wired and wireless receivers. His paper on the hardness of optimally broadcasting multiple video streams with different bit rates won the Best Paper Award in the IEEE Innovations 2008 conference. In addition to publications, he and his students develop actual systems, such as PROMISE, pCache, svcAuth, pCDN, and mobile TV testbed, and contribute the source code to the research community. The mobile TV testbed software developed by his group won the Best Technical Demo Award in the ACM Multimedia 2008 conference. His mobile multimedia streaming research with Cheng-Hsin Hsu, co-presenter of this tutorial, has been featured in multiple local and international news venues, including SFU NEWS, CTV British Columbia, Omni-TV, World Journal News, and ACM Tech News. In addition, a number of patents and commercialization activities based on his mobile multimedia research are being pursed by Simon Fraser University. He serves as the History Preservation Editor of the ACM Special Interest Group on Multimedia (SIGMM) Web Magazine. He has served as the program chair of the ACM International Workshop on Network and Operating Systems Support for Digital Audio and Video (NOSSDAV 2010). In addition, he has served on many technical program committees of major conferences in his research areas, including ACM Multimedia (meta-TPC and TPC), ACM Multimedia Systems, ACM/SPIE Multimedia Computing and Networking (MMCN), IEEE Conference on Network Protocols (ICNP), and IEEE Conference on Communications (ICC). He also has served on the editorial boards of the Journal of Multimedia and the International Journal of Advanced Media and Communication. He is a senior member of IEEE and a member of the ACM Special Interest Groups on Data Communications (SIGCOMM) and Multimedia (SIGMM). More information can be found at http://www.cs.sfu.ca/~mhefeeda/.
Cheng-Hsin Hsu received the Ph.D. degree from Simon Fraser University, Canada in 2009, the M.Eng. degree from University of Maryland, College Park in 2003, and the M.Sc. and B.Sc. degrees from National Chung-Cheng University, Taiwan in 2000 and 1996, respectively. He is a senior research scientist at Deutsche Laboratories, Los Altos, CA, where he leads the New Media research group. His research interests are in the area of multimedia networking and distributed systems. He has published more than 30 papers in leading journals, conference, and workshops. He is on the History Preservation Committee of the ACM Special Interest Group on Multimedia (SIGMM). He served as the Proceeding and Web Chair of the ACM International Workshop on Network and Operating Systems Support for Digital Audio and Video (NOSSDAV 2010). He was on the technical program committees of the ACM International Workshop on Network and Operating Systems Support for Digital Audio and Video (NOSSDAV 2010) , the International Conference on Embedded and Multimedia Computing (EMC 2010), and the ACM Workshop on Mobile Video Delivery (MoViD 2010).
T05 – Mobile Video Streaming in Modern Wireless Networks
Modern mobile devices, such as laptops, PDAs (Personal Digital Assistants), smart phones, and PMPs (Portable Media Players), have evolved to powerful mobile computers and can render rich multimedia content. Increasingly more users use mobile devices to watch videos streamed over wireless networks, and they demand more content at better quality. For example, market forecasts reveal that mobile video streaming, such as mobile TV, will catch up with gaming and music, and become the most popular application on mobile devices: more than 140 million subscribers worldwide by 2011. In this tutorial, we will present different approaches to deliver multimedia content over various wireless networks to many mobile users. We will study and analyze the main research problems in modern wireless networks that need to be addressed in order to enable efficient mobile multimedia services. The tutorial will cover common research problems in wireless networks such as HSDPA (High-Speed Downlink Packet Access), MBMS (Multimedia Broadcast Multicast Services) extension of cellular networks, WiMAX (Worldwide Interoperability for Microwave Access), LTE (Long Term Evolution), DVB-H (Digital Video Broadcasting – Handheld), and ATSC M/H (Advanced Television Systems Committee – Mobile/ Handheld). After giving the preliminaries of the considered wireless network standards, we will focus on several important research problems and present their solutions in details. These research problems include: (i) maximizing energy saving of mobile receivers, (ii) maximizing bandwidth utilization of wireless networks, (iii) minimizing stream switching time, and (iv) supporting heterogeneous mobile receivers. Finally, we will discuss open problems and future research directions in mobile multimedia.
Course outline
This tutorial consists of five parts. We first give a high-level overview on mobile video streaming systems, and present the leading-edge wireless networks. We then present the challenges in designing and implementing mobile video streaming systems. This is followed by discussion on concrete research problems and recently proposed solutions for them. We next discuss open research problems, and conclude the tutorial with outlook.
Introduction
We present a simple model for mobile video streaming systems, which abstracts away the common components to enable efficient mobile video streaming. We then specialize this model to several modern wireless networks, including HSDPA, MBMS extension of cellular networks, WiMAX, LTE, DVB-H, MediaFLO, and ATSC M/H. We then present the advantages/disadvantages of mobile video streaming over each of the considered wireless networks. Our comparison concentrates on their architectures, protocols, operation, deployment cost, and future potential. Our comprehensive comparison allows audience to understand the merits of individual wireless networks, and enables them to pick the wireless network that is most suitable to their needs. More importantly, our introduction clearly identifies the common components of all wireless networks. This enables general discussions on challenges and solutions in the rest of our tutorial, which can be readily applied to various wireless networks.
Challenges
We first discuss general challenges in multimedia wireless networks. For example, mobile video streaming systems need to cope with high error rates in wireless networks, because wireless channels are vulnerable to noise, fading, shadowing, and interference. In addition, some wireless networks deploy smaller cells to enable frequency reuse for higher spectrum efficiency. In these wireless networks, mobile video streaming systems must consider mobility and handoffs for mobile users to roam among cells. We also present challenges on providing good video streaming Quality-of-Experience (QoE) in mobile video streaming systems. The considered challenges can be classified into two groups: (i) user perspective and (ii) service provider perspective. User perspective challenges include optimizing streaming quality, energy saving, channel switching delay, and supporting heterogeneity. Streaming quality refers to smooth video playout on all mobile devices, which is only possible if video data are delivered on time without overflowing receiving buffer on mobile devices. Energy saving refers to how much time each mobile device can turn off its receiving circuit in order to conserve energy and prolong watch time. Channel switching delay is the time that a user waits before s/he starts viewing a selected video stream when a change of video stream is requested by that user. Supporting heterogeneity means allowing mobile users to watch the same video channels using mobile devices with heterogeneous resources, such as screen resolution, decoder capability, and battery level. Provider perspective problems include bandwidth efficiency and implementation complexity. Bandwidth efficiency refers to the number of video streams that can be concurrently streamed at a quality no worse than a given target quality within a bandwidth limitation. Implementation complexity considers the efforts to implement video encoders, transcoders, burst transmission schedulers, base stations, and network planning and deployment.
Problems and Recent Research Advances
We next discuss concrete research problems and present recently proposed solutions to them. These will include:
Open Research Problems
Several issues of mobile video streaming systems have not yet been rigorously studied. We will present these open problems. For example, we briefly describe an open problem of designing a hybrid streaming network in the following, while more open problems will be discussed in the tutorial. To minimize bandwidth requirements, depending on the number of receivers for individual videos, some videos may better be broadcast, while others may be more suitable to be unicast. For illustration, consider a video stream requested by a single mobile user, devoting a channel in broadcast networks to it may not be bandwidth efficient. In such scenario, streaming using unicast networks is more efficient. Therefore, hybrid unicast-broadcast networks lead to better bandwidth efficiency. Several works in the literature investigate the potential benefits of building such hybrid networks. However, several design challenges in such hybrid networks remain open.
Conclusions and Outlook
We will summarize our tutorial and review the most important take-aways. Moreover, we will give service providers some guidelines on choosing the wireless networks that are suitable to them. We believe our tutorial will largely simplify the future design and implementation of mobile video streams over modern wireless networks.
Audience
The tutorial discusses challenges and solutions in cutting-edge wireless networks and will attract both R&D engineers and academic scholars. This is a self-contained tutorial targeting intermediate and advanced audience. It will be of interest to researchers, graduate students, and engineers interested in video streaming to mobile devices.
Organizers/Presenters