Video-on-demand service in wireless networks is one important step to achieving the goal of providing video services anywhere anytime. Typically, carrier mobile networks are used to deliver videos wirelessly. Since every video stream comes from the base station, regardless of what bandwidth sharing techniques are being utilized, the media stream system is still limited by the network capacity of the base station. The key to overcome the scalability issue is to exploit resources available to mobile clients in a peer-to-peer setting. We observe that it is common to have a carrier mobile network and a mobile peer-to-peer network co-existing in a wireless environment. A feature of such hybrid environment is that the former offers high availability assurance, while the latter presents an opportunistic use of resources available at mobile clients. Our proposed video-on-demand technique, PatchPeer, leverages this network characteristic to allow the video-on-demand system to scale beyond the bandwidth capacity of the server. Mobile clients in PatchPeer are no longer passive receivers, but also active senders of video streams to other mobile clients. Our extensive performance study shows that PatchPeer can accept more clients than the current state-of-the-art technique, while maintaining the same quality-of-service to clients.

We consider the problem of supporting continuous spatial queries in a new and challenging network environment, namely a Mobile Peer-To-Peer (MP2P) network. Specifically, we propose a distributed technique, called ExtRange, that can efficiently answer continuous moving range queries in a MP2P network. The two key ideas in ExtRange are extended range and safe period. For each query, ExtRange extends the query monitoring region beyond the query range to ensure the accuracy of the query result under the dynamic condition of mobile nodes. Additionally, for each query it monitors, a mobile node computesa safe period, during which the mobile node does not have to update its location with the query node. Through analytical study, we prove that ExtRange guarantees the accuracy for query results when network communication is perfect. Using extensive simulation study, we show that ExtRange delivers high accuracy for query results with low associated costs under realistic simulation settings.

We present a system for video-on-demand streaming in peer-to-peer environment. We start by realizing the major differences between two types of streaming: live and on-demand. These observations lead to a set of problems that need to be solved for a peer-to-peer video-on-demand system. To address these problems, we propose a solution, which includes detail algorithms for building and maintaining an application multicast tree. The novel ideas in this paper are the use of a new caching scheme at clients, and the introduction of generation for better client management. Performance study based on simulation is carried out. The results show that our system outperforms a recently proposed system in a number of important performance metrics.

Given that the Internet does not widely support Internet protocol multicast while content-distribution-network technologies are costly, the concept of peer-to-peer could be a promising start for enabling large-scale streaming systems. In our so-called Zigzag approach, we propose a method for clustering peers into a hierarchy called the administrative organization for easy management, and a method for building the multicast tree atop this hierarchy for efficient content transmission. In Zigzag, the multicast tree has a height logarithmic with the number of clients, and a node degree bounded by a constant. This helps reduce the number of processing hops on the delivery path to a client while avoiding network bottlenecks. Consequently, the end-to-end delay is kept small. Although one could build a tree satisfying such properties easily, an efficient control protocol between the nodes must be in place to maintain the tree under the effects of network dynamics. Zigzag handles such situations gracefully, requiring a constant amortized worst-case control overhead. Especially, failure recovery is done regionally with impact on, at most, a constant number of existing clients and with mostly no burden on the server.

A peer-to-peer technique called ZIGZAG for single-source media streaming is designed . ZIGZAG allows the media server to distribute content to many clients by organizing them into an appropriate tree rooted at the server. This application-layer multicast tree has a height logarithmic with the number of clients and a node degree bounded by a constant. This helps reduce the number of processing hops on the delivery path to a client while avoiding network bottleneck. Consequently, the end-to-end delay is kept small. Although one could build a tree satisfying such properties easily, an efficient control protocol between the nodes must be in place to maintain the tree under the effects of network dynamics and unpredictable client behaviors. ZIGZAG handles such situations gracefully requiring a constant amortized control overhead. Especially, failure recovery can be done regionally with little impact on the existing clients and mostly no burden on the server.

Focuses on the problem of providing quality-of-service guarantee, scalability, and on-demand property to video streaming systems. We propose a solution called layered range multicast (LRM). LRM allows transmitting a range of data to a multicast group's members, which helps clients who request for service at different times join a same multicast efficiently without additional server bandwidth allocation. This is more advanced than the conventional multicast in which a late client joining an existing multicast, without bandwidth support from the server, must miss a certain portion of the video requested. Another advantage of LRM is its capability to support clients requesting various levels of service quality. In addition, LRM does not assume the existence of IP Multicast and therefore it can be implemented on the current Internet without degrading the very inefficient centralized approach. Our performance study results confirm the above benefits.

We design a peer-to-peer technique for single-source media streaming. This technique allows the media server to distribute content to many clients by organizing them into an appropriate tree rooted at the server. This application-layer multicast tree has a height O(logN) where N is the number of clients, and a node degree bounded by a constant. This helps reduce the number of processing hops on the delivery path to a client while avoiding network bottleneck. Consequently, the end-to-end delay is kept small. Although one could build a tree satisfying such properties easily, an efficient control protocol between the nodes must be in place to maintain the tree under the effects of network dynamics and unpredictable client behaviors. Our technique handles such situations gracefully requiring a constant amortized control overhead. Especially, failure recovery can be done regionally with little impact on the existing clients.