Congestion-Optimized Scheduling of Video over Wireless AD HOC Networks

Abstract

We analyze the benefits of information sharing between the application layer and the transport layer, for streaming video encoded at several different qualities, in a mobile wireless network. The application relies on statistics collected at the transport layer and on a video distortion model to select the highest quality that can be supported by the network. At the transport layer, congestion-distortion optimized scheduling is performed to select packets which maximize the received video quality. Experiments performed over a simulated multi-hop wireless network, with H.264 encoded video, show benefits of the proposed approach.

A multi-layer experimental study of multimedia and QoS communication in wireless mesh networks

“…For nodes pair (7,3), in our experiments, we found that the prime route (7, 5, 3) is quite stable. We found route (7,4,3) and route (7, 3) as backup routes. We observed that there are 8 occasions when the prime route fails, 28 occasions when the backup routes fail, and on 8 occasions both routes fail simultaneously.…”

“…Here δ is the minimum rate increment, which we set to be 10 kbps. 4: else if received n NACKs and no route brokens then 5: R cur = min(R max , R cur − n · δ). 6: else if window_length > CONG_AVOID then 7: R cur = min(R max , R cur − δ).…”

“…Various interesting problems in supporting multimedia communication over wireless ad hoc networks have previously been studied, e.g., [1][2][3][4][5][6]. To support multimedia traffic with QoS guarantee over wireless ad hoc networks, we need to investigate possible improvements on a number of layers.…”

“…Adaptive link layer techniques (e.g., [7,8]) can be used to adjust the capacity of individual wireless links to support delay-constrained traffic, possibly in multiple service classes. A congestionoptimized routing algorithm (e.g., [4]) will provide multiple paths to real-time multimedia streams and will intelligently provide the reliability guarantee. [15] propose an on-demand routing scheme called Split Multipath Routing (SMR) that establishes and utilizes multiple routes of maximally disjoint paths.…”

Cross-layer Designs: A Survey

“…TCP deploys congestion control through its congestion window mechanism, which, as stated earlier, is not very effective in wireless networks. Setton et al [17] used a mobile ad hoc network using 802.11 to implement a cross-layer scheduling for video transmission. They used a distortion model based on their earlier works.…”