eCMT-SCTP: Improving Performance of Multipath SCTP with Erasure Coding Over Lossy Links

Performance of transport protocols on lossy links is a well-researched topic, however there are only a few proposals making use of the opportunities of erasure coding within the multipath transport protocol context. In this paper, we investigate performance improvements of multipath CMT-SCTP with the novel integration of the on-the-fly erasure code within congestion control and reliability mechanisms. Our contributions include: integration of transport protocol and erasure codes with regards to congestion control; proposal for a variable retransmission delay parameter (aRTX) adjustment; performance evaluation of CMT-SCTP with erasure coding with simulations. We have implemented the explicit congestion notification (ECN) and erasure coding schemes in NS-2, evaluated and demonstrated results of improvement both for application goodput and decline of spurious retransmission. Our results show that we can achieve from 10% to 80% improvements in goodput under lossy network conditions without a significant penalty and minimal overhead due to the encoding-decoding process

Adaptive end-to-end optimization of mobile video streaming using QoS negotiation

Video streaming over wireless links is a non-trivial problem due to the large and frequent changes in the quality of the underlying radio channel combined with latency constraints. We believe that every layer in a mobile system must be prepared to adapt its behavior to its environment. Thus layers must be capable of operating in multiple modes; each mode will show a different quality and resource usage. Selecting the right mode of operation requires exchange of information between interacting layers. For example, selecting the best channel coding requires information about the quality of the channel (capacity, bit-error-rate) as well as the requirements (latency, reliability) of the compressed video stream generated by the source encoder. In this paper we study the application of our generic QoS negotiation scheme to a specific configuration for mobile video transmission. We describe the results of experiments studying the overall effectiveness, stability, and dynamics of adaptation of our distributed optimization approach

An Efficient Transport Protocol for delivery of Multimedia An Efficient Transport Protocol for delivery of Multimedia Content in Wireless Grids

A grid computing system is designed for solving complicated scientific and commercial problems effectively,whereas mobile computing is a traditional distributed system having computing capability with mobility and adopting wireless communications. Media and Entertainment fields can take advantage from both paradigms by applying its usage in gaming applications and multimedia data management. Multimedia data has to be stored and retrieved in an efficient and effective manner to put it in use. In this paper, we proposed an application layer protocol for delivery of multimedia data in wireless girds i.e. multimedia grid protocol (MMGP). To make streaming efficient a new video compression algorithm called dWave is designed and embedded in the proposed protocol. This protocol will provide faster, reliable access and render an imperceptible QoS in delivering multimedia in wireless grid environment and tackles the challenging issues such as i) intermittent connectivity, ii) device heterogeneity, iii) weak security and iv) device mobility.Comment: 20 pages, 15 figures, Peer Reviewed Journa

Design and analysis of a beacon-less routing protocol for large volume content dissemination in vehicular ad hoc networks

Largevolumecontentdisseminationispursuedbythegrowingnumberofhighquality applications for Vehicular Ad hoc NETworks(VANETs), e.g., the live road surveillance service and the video-based overtaking assistant service. For the highly dynamical vehicular network topology, beacon-less routing protocols have been proven to be efficient in achieving a balance between the system performance and the control overhead. However, to the authors’ best knowledge, the routing design for large volume content has not been well considered in the previous work, which will introduce new challenges, e.g., the enhanced connectivity requirement for a radio link. In this paper, a link Lifetime-aware Beacon-less Routing Protocol (LBRP) is designed for large volume content delivery in VANETs. Each vehicle makes the forwarding decision based on the message header information and its current state, including the speed and position information. A semi-Markov process analytical model is proposed to evaluate the expected delay in constructing one routing path for LBRP. Simulations show that the proposed LBRP scheme outperforms the traditional dissemination protocols in providing a low end-to-end delay. The analytical model is shown to exhibit a good match on the delay estimation with Monte Carlo simulations, as well

Squash: low latency multi-path video streaming using multi-bitrate encoding

The demand for low latency video streaming has dramatically increased as live video streaming applications, such as Twitch and Youtube Live, are becoming more popular. According to the 2021 Bitmovin video developer report, the biggest challenge that video developers are experiencing today is providing low latency video streaming. One of the most common on-site live streaming methods is using a wireless LTE network. There have been many approaches for characterizing wireless links and accurately measuring available bandwidth to provide low latency streaming over a wireless LTE network link. However, even with fine-grained bandwidth estimation, video streaming on a single LTE link is still susceptible to unexpected network delay from a sudden drop in available bandwidth or temporal disconnection. People can utilize multiple wireless LTE links to overcome the limitations of using a single LTE link for low latency video streaming. Using multiple links can enhance video quality through increased bandwidth and resilience. However, multi-homed low latency video streaming protocols may achieve lower video quality than single-homed protocols when a frame is split and sent over more than one link. Suppose one of the links becomes congested or gets disconnected. In that case, the part of the frame sent on stable links must wait until the packets sent on the problematic link are re-transmitted through another link. Re-transmission requires at least one extra round trip time. A video player may skip the late frame or serve only the received part of the frame due to the re-transmission delay. Ferlin et al. suggest using Forward Error Correction (FEC) on Multipath TCP (MPTCP) to reduce re-transmission delay. However, FEC is not helpful in the event of a significant bandwidth drop. If the sender does not use sufficient redundancy to handle a significant bandwidth drop, the receiver will not receive enough blocks to decode the video data. FEC requires using a large portion of the network bandwidth for redundancy to handle significant bandwidth drops even when the links are stable. In this thesis, I present Squash, a low latency video transport protocol that encodes each frame at multiple bitrates and sends them across different links to minimize video stream disruption in the event of unexpected bandwidth drops. The encoder encodes a frame into multiple different bitrates, which are high-bitrate and low-bitrate. When a high- bitrate frame cannot arrive on time due to congestion from an unexpected drop in available bandwidth, the low-bitrate frame is used to replace the missing frame. This is because the low-bitrate frame is smaller and is sent on the links that are disjoint from those used by the high-bitrate frame. To the best of my knowledge, Squash is the first architecture that uses multi-bitrate frames to increase resilience against unexpected bandwidth drops in low latency video streaming over multiple wireless LTE links. In emulated wireless LTE network environment using Mahimahi network traces, the average SSIM of the video streamed on Squash is 13 – 58% higher than that streamed on the baseline protocol, which is designed in the same manner as Squash except that it employs single-frame encoding

Cross layer techniques for flexible transport protocol using UDP-Lite over a satellite network

Traditional real-time multimedia and streaming services have utilised UDP over RTP. Wireless transmission, by its nature, may introduce a variable, sometimes high bit error ratio. Current transport layer protocols drop all corrupted packets, in contrast, protocols such as UDP-Lite allow error-resilient applications to be supported in the networking stack. This paper presents experimental quantitative performance metrics using H.264 and UDP Lite for the next generation transport of IP multimedia, and discusses the architectural implications for enhancing performance of a wireless and/or satellite environment