A novel cross-layer design using comb-shaped quadratic packet mapping for video delivery over 802.11e wireless ad hoc networks

Abstract

Cross-layer design is a promising direction and challenging issue for quality delivery of multimedia over wireless networks. This article proposes a cross-layer design which can substantially enhance the transmission quality of video streaming over 802.11e ad hoc networks. The proposed design consists of two parts: a dispersive video frame importance (DVFI) scheme in the application layer that can correctly label the priorities of video packets, and a comb-shaped quadratic mapping (CQM) algorithm in the medium access control (MAC) layer that can provide a better congestion control mechanism among the multiple access category (AC) queues than 802.11e Enhanced Distributed Channel Access (EDCA) for wireless video delivery. The DVFI value of a video frame is measured from its own transmission loss and the accompanied impact to other coding-dependent video frames, and is accordingly adopted to prioritize the video frame associated packets. When these prioritized video packets arrive at the reserved AC queue in the MAC layer, the CQM algorithm can accordingly provide multi-branched service differentiation among them by dynamically downward mapping less significant video packets to lower-priority ACs based on the instant congestion level of the reserved AC queue, which can thus offer a better channel access resource to those video packets of higher priorities. In addition, the minimum-delay-time rule embedded in the CQM will select a better destiny for those downward mapped video packets among the lower-priority AC queues. Under various video-input-rate and cross-traffic tests, the simulation results show that this study outperforms the existing works, including EDCA, Adaptive Mapping, and Enhanced Adaptive Mapping.

A novel cross-layer design using comb-shaped quadratic packet mapping for video delivery over 802.11e wireless ad hoc networks

“…The EvalVid multimedia framework [28] integrated with the ns-2 network simulator [29] was used to provide the H.264 video streaming [30] over an ad hoc wireless network simulation environment, where the DSDV routing protocol was used and the adopted data rate of the wireless link was 1 Mbps. Four ad hoc nodes were setup, where one served as a video server and another as a video client with cross Node 2) and (Node 3 Node 4).…”

RGI: Bit-rate modeling of a novel real-time picture-importance scheme for robust video over the LTE downlink

“…Note that the I/P and EPL schemes are real-time applicable since their priority orderings are both assumptionbased: the I/P scheme simply assumes I > P, and the EPL scheme obtains its assumption based on the coding positions of member pictures in the GOP. DVFI, proposed in our previous work [1], is based on the concept called dispersive video picture importance, where each picture of a video sequence has its own importance level by measuring the total sum of quality impairments Y-PSNR k as defined by Eq. 1, formed by two factors: (1) Y-PSNR k the quality impairment due to a lost video picture itself (say, the k th picture of a video sequence) during transmission, i.e., the imperfection after error concealment by picture copy, and (2) Y-PSNR m's k its error propagation to other member pictures in the same GOP, denoted by m's.…”

“…Some of these importance schemes involve measuring the impact of coding error propagation of each lost picture to other neighboring coding-dependent pictures in order to enable large priority granularity and high accuracy, but thus cannot be applicable to a real-time scenario due to extra coding delay (e.g., DVFI [1]), whereas the others focus on their real-time applicability (e.g., I/P or EPL [2]) simply by priority assumption based on mutual coding dependencies among member pictures in the same group of pictures (GOP). More technical details of these schemes and related works are described in Section II.…”