Multiple Description Coded Video Streaming with Multipath Transport in Wireless Ad Hoc Networks

Recent advances in wireless communications and mobile networking have dramatically increased the popularity of multimedia services for mobile users, with wireless video streaming at their fingertips. To facilitate efficient acquisition of video content, proxy caching has been widely used by wireless service providers (WSPs), which typically deploy cache servers at mobile switching centers (MSCs). However, capacity provisioning of cache servers is challenging, given the dynamic user demands and the limited cache server resources. With increased densities of wireless service deployment, it is increasingly common that mobile users are covered by more than one WSP within an area. This brings opportunities of a collaborative caching paradigm among the cache servers deployed at different MSCs. In this paper, we explore the benefits of collaborative caching in wireless streaming services, addressing both challenges of incentives and truthfulness of selfish WSPs. We propose a collaborative mechanism that maximizes the social welfare in the context of Vickrey-Clarke-Groves (VCG) auctions, in which cache servers cooperate in the trading of their resources in a self-enforcing manner. Experimental results demonstrate that superior performance can be achieved with respect to the quality of video streaming.

Video streaming over wireless ad-hoc networks requires appropriate routing and rate allocation mechanisms that efficiently adapt to the characteristics of such environments. The special features of ad-hoc networks also motivate us to introduce proper mechanisms in video coding, error concealment and various related areas. In this paper, we propose a framework for video streaming over wireless ad-hoc networks which utilizes the cooperation among network layers to perform the mentioned activities. We discuss the key parameters to be noticed in such a framework and explore several approaches in video streaming and rate allocation and select the suitable methods for our purpose. Focusing on the retransmission of lost video frames in response to ARQ requests, we try to minimize the delay between sending the ARQ request and receiving the lost frame, by selecting a route in which a node assists us in video streaming. Simulation results show the feasibility and the efficiency of the proposed framework.

Streaming videos over wireless networks suffers from low video quality due to network ability limitations. The quality of the channel and the characteristics of source play the major role in transmitting video stream over mobile environments. On failure of wireless video transmission, retransmission method was employed to improve the reliability of wireless link. However, retransmission of video leads to significant impact on energy consumption and bounded average waiting time is also increased. The longer waiting time on retransmission results in buffer starvation. Therefore, it is desirable to reduce the variable bit rate of transmitted video signal and increase the stability level when buffer starvation is occurs. In order to overcome such limitation, a technique named Response based Stabilization Analysis (RSA) using Distributed Optimality Bit Rate Allocation (RSA-DOBRA) is proposed in this paper. Initially, video stream is segregated into frames of different classes (i.e., size). Each frame is transmitted based on the variable bit rate response using Optimal Quantization process. Secondly, Linear Lyapunov Functions is employed with RSA to prove the stability of different bit rates on wireless video streaming. The application of Linear Lyapunov Function maintains the stability level of bit rate on different class of frame transmission on wireless link. Finally, Distributed Optimality Bit Rate Allocation uses the time slicing procedure to reduce the bounded average waiting time. RSA performs the time slicing based on multiplexed wireless video transmission on variable bit rate to avoid buffer starvation. RSA at the final stage reduces the energy consumption by improving the reliability of wireless link. Experiment is conducted on factors such as buffered starvation rate, waiting time on video frame transmission, and energy consumption rate.

Multiple description (MD) coding is a new video coding technique that is uniquely suitable for video transport over wireless ad hoc networks. In this paper, we consider the problem of how to support video multicast with MD video in ad hoc networks. We follow an application-centric, cross-layer routing approach with the objective of minimizing the overall video distortion. We propose an MD video multicast scheme where multiple source trees are used. Furthermore, each video description is coded into multiple layers in order to cope with diversity in wireless link bandwidths. Based on this multicast model, we formulate the cross-layer multicast routing as a combinatorial optimization problem and propose an efficient Genetic Algorithm (GA)-based metaheuristic solution procedure. Performance comparison with existing approaches show significant gains for a wide range of network operating conditions.

This paper presents a wireless video streaming system over Ultra Wide Band (UWB) radio. Wireless video steaming is not a possibility so far due to its high bandwidth requirements and high power consumption. With Ultra Wide Band (UWB), a low power, high speed radio technology standard developed by the WiMedia Alliance; the dream of wireless video streaming become true. By giving the fact of UWB, 480 Mbps with transmission mask of -41 dbm/MHz; the UWB supports uncompressed or lossless compressed video screen size up to SVGA (800x600x24) with 30 frames/second rate. This is an extraordinary achievement concerning wireless video application. This paper will introduce a demonstration system that uses a Nokia 7710 phone as a UWB transmitter and a projector as a UWB receiver. The demonstration is a result of collaboration between Nokia Research Center Helsinki and WiQuest Communications Inc. USA.

In a typical mobile ad hoc network, mobile computing devices wander autonomously and communicate via temporary links in a self-organized computing system without any central administrator or infrastructure support. To support truly ad hoc impromptu communication among such uncoordinated devices, a data multipath routing algorithm can be used because there is no need to rely on a centralized encryption facility (e.g., a PKI server) or complicated distributed keying protocols. In this paper, we propose a data multipath routing algorithm called multipath TCP security (MTS) to enhance the data security. In MTS, the source node adaptively chooses the available rather than exhaustively testing the stored routes one by one. Simulation results show that our algorithm provides a reasonably good level of security and performance.

The purpose of this paper is to investigate the flat routing and hierarchical routing protocols in ad hoc wireless networks. Flat and hierarchical routing are two most typical routing protocols in wireless ad hoc networks. There have been many researches working on studying different flat or hierarchical routing protocols separately. However, there are little works about a comprehensive comparison study between these two kinds of routing protocols. As there are many protocols for both flat and hierarchical routing protocol, it is necessary to study their advantages and disadvantages, so that we could provide guidance for the deployment of different protocols in different networks configuration. This paper will study the performance of hierarchical routing protocols as compare to flat routing protocols. Our study is based on an extensive simulation using NS2

Video streaming on smartphones is one of the most popular but also most energy hungry services today. Using mobile video services results in two contradictory sources of energy waste for smartphones: i) energy waste because of excessively aggressive prefetching of content that the user will not watch because of abandoning the session, and ii) excessive amount of tail energy, which is energy wasted by keeping the wireless interface powered on after receiving a chunk of content; this is caused by prefetching chunks that are too small. To remedy this, we propose a novel download scheduling algorithm based on crowd-sourced video viewing statistics. Our algorithm judiciously evaluates the probability of a user interrupting a video viewing in order to perform the right amount of prefetching. In this way, the algorithm balances the amount of the two above-mentioned kinds of energy waste. By simulations, we show that our scheduler cuts the energy waste to half compared to existing download strategies. We have also developed an Android prototype that implements the download scheduler together with a novel downloader that speeds up the download by exploiting the Fast Start technique. The prototype exhibits the desired properties of the scheduler, and its faster downloading mechanism yields further energy savings of up to 80% compared to the default Android YouTube app.

At present, domestic and international research on the video transmission mainly concentrated in video coding, multipath transmission, multicast transmission. The transmission and QoS security technology will be studied to against the characteristics of video transmission and wireless ad hoc network.How to transfer more video streaming under conditions of the limited network resource is a meaningful topic.In this paper,the conception of user level into service classification is introduced and a framework named UVQM is proposed.The UVQM can provide QoS security for video transmission and ensure more streaming transmitted without congestion.

Ad Hoc network is one of the popular wireless multi-hop networks. Nodes or Users in Ad Hoc network can move randomly and freely to maintain communication without the control of the fixed infrastructure. Due to the limited transmission power and wireless coverage of the terminal, if two terminals that are beyond their respective transmission radius need communicate, they must use other intermediate or relay nodes for packet forwarding, so that a wireless Ad Hoc network is formed among these nodes. In this paper, the current state-of-the-art multipath routing protocols for Ad Hoc networks are reviewed. Particularly, the pros and cons of them are analyzed. Finally, they are summarized and compared.

Quality of service (QoS) of delay sensitive application like video stream is majorly affected by instantaneous channel conditions over noisy mobile ad-hoc networks (MANETs). Methods like forward error correction (FEC) and automatic repeat request (ARQ), multiple description coding (MDC), and MDC with error correction (MDC_EC) design to recover the quality of the video in noisy wireless networks under perform in MANETs because of their high overheads and high retransmission delay. MDC and MDC_EC produce unacceptable video quality at the receiver and fail to fulfil the QoS requirements of the video applications. We have proposed a novel routing protocol to support QoS and reduce overheads. The proposed work is twofold: i) redefine the distortion model to estimate the distortion of the transmitted video; ii) proposed a novel routing protocol model to mitigate the impact of channel noise on the video quality through selected retransmission of noisy descriptors (MDC_EC_RE).

In recent years, wireless ad hoc networks (WANETs) have become very popular due to their wide range of applications and their ability to be deployed under normal and harsh conditions while supporting high data rates. Although many intrusion detection and trust-based systems have been developed to protect ad hoc networks against misbehaviors such as rushing attacks, query-flood attacks, and selfishness of nodes, these defense mechanisms are still not able to detect protocol compliant attacks called Jellyfish (JF) attacks. They target closed-loop flows such as TCP that are responsive to network conditions like delay and packet losses and can easily partition the network. In this paper, we introduce a security scheme called JAM (Jellyfish Attacks Mitigator) which can be used to detect and mitigate Jellyfish attacks in ad hoc networks.KeywordsWireless Ad hoc NetworksSecurityDenial of ServiceJellyfish Attacks

The TCP (Transmission Control Protocol) is a critical component in an ad hoc wireless network because of its pervasive usage in various important applications. However, TCP’s congestion control mechanism is notoriously ineffective in dealing with time-varying channel errors even for a single wireless link. Indeed, the adverse effects of the inefficient usage of wireless bandwidth due to the large TCP timers are more profound in a multihop communication session. In this paper, we design and evaluate local recovery (LR) approaches for maintaining smooth operations of a multihop TCP session in an ad hoc network. Based on our NS-2 simulation results, we find that using the proposed LR approaches is better than using various well-known ad hoc routing algorithms which construct completely new routes.

In this paper, we study a flow control problem considering network coding in wireless ad-hoc networks with multi-path routing. As a network coding scheme, we use XOR network coding, in which each node bitwise-XORs some packets received from different sessions, and then broadcasts this coded packet to multiple nodes in a single transmission. This process can reduce the number of required transmissions, and thus can improve network utilization, especially if it is used with appropriate network coding-aware protocols. Considering this XOR network coding, we formulate an optimization problem for flow control that aims at maximizing network utility. By solving the optimization problem in a distributed manner, we implement a distributed flow control algorithm that provides the optimal transmitting rate on each of multiple paths of each session. The simulation results show that our flow control algorithm performs well exploiting the advantages of network coding and provides significant performance improvement.

In this paper, we present the set of factors in the physical layer that are relevant to the performance evaluation of the routing protocols. Such factors consist of signal reception, path loss, fading and interference considerations. Therefore it would be desirable for routing algorithms in wireless ad hoc networks, to be able to select paths that are more likely to be stable. With this in mind we adopt a numerical approach based on Finite State Markov Chain channel model to study the performance of an ad hoc routing protocol under various radio propagation models. Further this paper presents a new cross-layer algorithm for joint physical and routing layers in wireless ad hoc networks, applying this to the Optimized Link State Routing (OLSR), protocol. We address the problem of link and route stability, focusing particularly on multipoint relay (MPR) selection method, to find the most optimal routes between any pair of nodes. Our simulation results indicate that the network throughput is greatly improved and the delay is significantly decreased using this cross-layer mechanism, compared to the original OLSR.