Changqiao Xu

CMT-QA: Quality-Aware Adaptive Concurrent Multipath Data Transfer in Heterogeneous Wireless Networks

Mobile devices equipped with multiple network interfaces can increase their throughput by making use of parallel transmissions over multiple paths and bandwidth aggregation, enabled by the stream control transport protocol (SCTP). However, the different bandwidth and delay of the multiple paths will determine data to be received out of order and in the absence of related mechanisms to correct this, serious application-level performance degradations will occur. This paper proposes a novel quality-aware adaptive concurrent multipath transfer solution (CMT-QA) that utilizes SCTP for FTP-like data transmission and real-time video delivery in wireless heterogeneous networks. CMT-QA monitors and analyses regularly each paths data handling capability and makes data delivery adaptation decisions to select the qualified paths for concurrent data transfer. CMT-QA includes a series of mechanisms to distribute data chunks over multiple paths intelligently and control the data traffic rate of each path independently. CMT-QAs goal is to mitigate the out-of-order data reception by reducing the reordering delay and unnecessary fast retransmissions. CMT-QA can effectively differentiate between different types of packet loss to avoid unreasonable congestion window adjustments for retransmissions. Simulations show how CMT-QA outperforms existing solutions in terms of performance and quality of service.

Performance Evaluation of Multimedia Content Distribution Over Multi-Homed Wireless Networks

The growing availability of IP based heterogeneous wireless access technologies coupled with the increasing capabilities of mobile devices is creating opportunities for multimedia distribution. Through its multi-homing feature, the ability to support multiple network connections in a single end to end association, the transport layer Stream Control Transmission Protocol (SCTP) can enable seamless and transparent communication sessions over multiple heterogeneous networks. This paper analyzes the performance of multimedia distribution when making use of two multi-homing SCTP-based approaches: Single Path Transfer and Concurrent Multi-path Transfer, in which a single or all paths within an association are used simultaneously for data transmission. In this investigation various retransmission policies and different parameter sets are used in turn and recommendations are made for achieving best results during video delivery. In order to perform this study a novel realistic evaluation tool-set was proposed and is described, which can simulate video delivery over SCTP. Our simulation results and analysis show how to optimize the transmission of multimedia content over SCTP associations in both single and multipath scenarios.

TB2F: Tree-bitmap and bloom-filter for a scalable and efficient name lookup in Content-Centric Networking

Content-Centric Networking (CCN) is an entirely novel networking paradigm, in which packet forwarding relies upon lookup operations on content names directly instead of fixed-length host addresses. The unique features of CCN names, i.e., variable length, huge cardinality, and hierarchical structure, introduce new challenges that could hinder the deployment of such a new architecture at the Internet scale. In this paper, we make an in-depth study of characteristics of large-scale CCN names, and propose a simple yet efficient CCN-customized name lookup engine (named by TB2F), which capitalizes the strengths of Tree-Bitmap (TB) and Bloom-Filter (BF) mechanisms, while counteracts their main limitations. To this end, TB2F splits CCN prefix into a constant size T-segment and a variable length B-segment with a relative short length, which are treated using TB and BF, respectively. Furthermore, an optimal length of the T-segment is found to improve the lookup efficiency. Experimental comparisons with respect to the reference Name Prefix-Trie and Bloom-Hash have been also carried out. The results show that TB2 F properly configured has good scalability and efficiency by (i) speeding up lookup operations and reducing the false positive rate with respect to Bloom-Hash; (ii) requiring less memory than Name Prefix-Trie; (iii) achieving a low overhead in updating operations in the large scale case.

Performance-Aware Mobile Community-Based VoD Streaming Over Vehicular Ad Hoc Networks

Leveraging the development of mobile communication technologies and increased capabilities of mobile devices, mobile multimedia services have set new trends. To support high-quality Video-on-Demand (VoD) in mobile wireless networks, using virtual community-based approaches to balance the efficiency of content sharing and maintenance cost of performance-aware solutions has attracted increasing research interest. In this paper, we propose a novel Performance-aware Mobile Community-based VoD streaming solution over vehicular ad hoc networks (PMCV). PMCV relies on a newly designed mobile community detection scheme and an innovative community member management mechanism. The former employs a novel fuzzy ant-inspired clustering algorithm and an innovative mobility similarity estimation model to group together the mobile users with similar behavior in terms of playback and movement into mobile communities. The latter introduces the role and task of members, member join and leave, collaborative store and search for resources, and replacement of a broker member. Simulation-based testing shows how PMCV outperforms another state-of-the-art solution in terms of performance.

Distributed Storage-Assisted Data-Driven Overlay Network for P2P VoD Services

Providing VCR-like operations in peer-to-peer (P2P) environments is a significant challenge. This paper proposes a distributed storage-assisted data-driven overlay network (SDNet) to support P2P video-on-demand (VoD) services. It integrates two networks: a data-driven overlay network (DONet) and a multi-way tree. DONet is enhanced and used for the routine video distribution based on the buffer overlapping mechanism and gossip protocol. A novel algorithm which uses a multi-way tree structure and extra pre-fetching buffers at the nodes is proposed to support efficient VoD operations. Videos are divided into uniform segments, pre-fetched and stored in a distributed manner along the tree topology. The cooperation between DONet-based video delivery and the tree-located multimedia components enable multimedia streaming interactive commands to be performed efficiently. This paper presents and discusses the structure of SDNet and the distributed storage scheme and details the cooperation procedure. Simulation-based testing results show how the proposed SDNet is an efficient interactive streaming solution in a P2P environment.

Socially aware mobile peer-to-peer communications for community multimedia streaming services

Mobile multimedia streaming services have become the main reason behind the latest increase in mobile data traffic worldwide. The enormous user base, frequency of data exchange, and demand for high-quality multimedia content open up new challenges to offer good QoS levels in mobile multimedia streaming systems. This article presents an innovative SMMC that integrates performance factors with aspects such as demand, socialization, mobility, and delivery. Simulation results demonstrate that SMMC achieves high content sharing efficiency and increased QoS levels.

Scalable Name Lookup with Adaptive Prefix Bloom Filter for Named Data Networking

In Named Data Networking (NDN), packet forwarding decisions rely upon lookup operations on variable-length hierarchical names instead of fixed-length host addresses. This pivotal feature introduces new challenges in the deployment of NDN at the Internet scale. In this letter, a novel Name Lookup engine with Adaptive Prefix Bloom filter (NLAPB) is conceived, in which each NDN name/prefix is split into B-prefix followed by T-suffix. B-prefix is matched by Bloom filters whereas T-suffix is processed by the small-scale trie. The length of B-prefixes (and T-suffixes) is dynamically throttled based on their popularity in order to accelerate the lookup. Experimental results show that: (i) NLAPB is able to lower the false positive rate with respect to a lookup entirely based on Bloom filters; (ii) it decreases the memory requirements with respect to a trie-based approach; (iii) it reduces processing time with respect to both them.

A Balanced Tree-Based Strategy for Unstructured Media Distribution in P2P Networks

Most research on P2P multimedia streaming assumes that users access video content sequentially and passively. Unlike P2P live streaming in which the peers start playback from the current point of streaming when they join the streaming session, in P2P video-on-demand streaming VCR-like operations such as forward, backward, and random-seek have to be supported. Providing this level of interactive streaming service in a P2P environment is a significant challenge. This paper proposes a balanced binary tree-based strategy for unstructured video-on- demand distribution in P2P networks (BBTU). BBTU assumes videos can be divided into several segments which can be fetched from different peers. BBTU involves two steps: 1) balance binary tree construction based on a prefetching algorithm in order to support interactivity; 2) unstructured video dissemination over network based on gossip protocol, which is the overlay for video distribution. Analysis and simulation show how BBTU is an efficient interactive streaming solution in P2P environment.

Cross-Layer Fairness-Driven Concurrent Multipath Video Delivery Over Heterogeneous Wireless Networks

The growing availability of various wireless access technologies promotes increasing demand for mobile video applications. Stream control transmission protocol (SCTP)-based concurrent multipath transfer (CMT) improves the wireless video delivery performance with its parallel transmission and bandwidth (BW) aggregation features. However, the existing CMT solutions deployed at the transport layer only are not accurate enough due to lower layer uncertainties, such as variations of the wireless channel. In addition, CMT-based video transmission may use excessive BW in comparison with the popular Transmission Control Protocol (TCP)-based flows, which results in unfair sharing of network resources. This paper proposes a novel cross-layer fairness-driven (CL/FD) SCTP-based CMT solution (CMT-CL/FD) to improve video delivery performance, while remaining fair to the competing TCP flows. CMT-CL/FD utilizes a cross-layer approach to monitor and analyze path quality, which includes wireless channel measurements at the data-link layer and rate/BW estimations at the transport layer. Furthermore, an innovative window-based mechanism is applied for flow control to balance delivery fairness and efficiency. Finally, CMT-CL/FD intelligently distributes video data over different paths depending on their estimated quality to mitigate packet reordering and loss, under the constraint of TCP-friendly flow control. Simulation results show how CMT-CL/FD outperforms existing solutions in terms of both video delivery performance and TCP-friendliness.

A Novel Cooperative Content Fetching-Based Strategy to Increase the Quality of Video Delivery to Mobile Users in Wireless Networks

Cooperatively fetching video content with the help of other mobile nodes can release some of the pressure on storage and bandwidth of the constrained mobile devices in wireless networks and speeds up the localization process of video resources so as to support better quality of viewing experience. In this context, the discovery of the appropriate mobile cooperative node becomes a key factor and is also a challenge for the deployment of such a fetching scheme. In this paper, we introduce a novel cooperative content fetching-based strategy to increase the quality of video delivery to mobile users in wireless networks (CCF). By intelligently monitoring the real-time variation in the state of the one-hop neighbors (immediate-neighbors) of the video resource downloader, CCF employs an innovative estimation model to measure the stability of these immediate-neighbors. In order to enhance the cooperative fetching efficiency, CCF designs a communication quality forecast model to measure link reliability and forecast the available bandwidth. By making use of a newly proposed cooperative fetching algorithm, CCF can speed up fetching and disseminating of video resources with the help of cooperative neighbors selected in terms of stability and communication quality. Simulation results show how CCF obtains higher selection accuracy of cooperative neighbors, lower average end-to-end delay, lower average packet loss ratio, higher average throughput, higher video quality, and lower maintenance overhead in comparison with state-of-the-art solutions.