Cross-Layer Techniques for Adaptive Video Streaming over Wireless Networks

Abstract

Real-time streaming media over wireless networks is a challenging proposition due to the characteristics of video data and wireless channels. In this paper, we propose a set of cross-layer techniques for adaptive real-time video streaming over wireless networks. The adaptation is done with respect to both channel and data. The proposed novel packetization scheme constructs the application layer packet in such a way that it is decomposed exactly into an integer number of equal-sized radio link protocol (RLP) packets. FEC codes are applied within an application packet at the RLP packet level rather than across different application packets and thus reduce delay at the receiver. A priority-based ARQ, together with a scheduling algorithm, is applied at the application layer to retransmit only the corrupted RLP packets within an application layer packet. Our approach combines the flexibility and programmability of application layer adaptations, with low delay and bandwidth efficiency of link layer techniques. Socket-level simulations are presented to verify the effectiveness of our approach

An End-To-End Video Transmission System over Various Wireless Environments

“…A cross layer scheduling approach with adaptive modulation and coding is presented in [14]. Authors in [15] proposed adaptation mechanism where application layer and lower layer are combined for low-delay wireless video streaming. Error control and adaptation mechanism for error-free video transmission are proposed by Van Der et al [16].Coopetition based mechanism in proposed in [17], in this mechanism wireless stations can optimally and dynamically adapt their cross layer transmission strategies to improve multimedia quality and power consumption.…”

Joint Uplink and Downlink Optimization for Real-Time Multiuser Video Streaming Over WLANs

“…To improve the effective throughput, a wireless video framework was proposed to utilize hybrid automatic repeat request (HARQ) with multiple descriptions in the application layer [16]. Recently, cross-layer design methodologies that jointly optimize the resource allocation in different communication layers have been shown as an effective approach to improve the overall system performance [17], [18]. By adaptively utilizing the retry limit of the MAC layer with priority queueing, a wireless video scheme exploring unequal importance of video bitstreams was proposed in [19].…”

“…Thus, if user selects PHY mode for uplink and downlink as and , respectively, and sends packets from the sender to the server, the expected transmission time along user 's uplink is (14) The expected number of packets successfully arriving at server is , and expected transmission time along user 's downlink is (15) The overall expected transmission time from user through the server to his/her conversation partner is (16) We formulate the overall distortion management problem in the video streaming system as an optimization problem that searches for each user's transmission mode to minimize the maximum of all users' expected distortion, subject to the maximal available transmission time. That is (17) where is the quality weighting factor and the perceptual distortion function. Because of the integer valued parameters in transmission mode, the problem (17) is hard.…”

“…The complexity of finding the optimal transmission modes for all users through full search is , where is the number of all feasible transmission modes bounded by the maximum transmission delay and number of PHY modes provided by WLAN. To meet the real-time requirement of the proposed system, we propose a fast algorithm in the next subsection to find a near-optimal solution to problem (17). As a proof of concept, we consider the case of providing uniform mean-squared distortion among all users, i.e., , , and .…”

Real-Time Video Streaming in Multi-hop Wireless Static Ad Hoc Networks

“…Our goal is to develop and implement an efficient algorithm and test it in a realistic physical model. Many works have been published on the topic of multi-hop routing in wireless networks including real-time video streaming (see [SYZ + 05, KPS + 06, Sha05,vDS05]). In these works it is acknowledged that cross layer algorithms are required to utilize the capacity of the network.…”