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            About AMP Lab        Projects        Downloads        Publications        People        Links

Group Member

Amy, Mei-Hsuan Lu
PhD. Student

Personal Homepage:  http://www.ece.cmu.edu/~meihsual
Email: amylu@cmu.edu

Office: Porter Hall B42
Lab: Porter Hall B6
Phone: 412-268-7114
Fax: 412-268-3890
Mailing Address:
Department of ECE, Carnegie Mellon University,
5000 Forbes Avenue, Pittsburgh,
PA 15213-3890

[Research Interests]        [Project]      [Publications

Research Interests

Cross-layer Optimization for Video Streaming over Wireless Networks:


My research interests lie on all topics about cross-layer optimization for wireless video streaming. We believe a cross-layer view instead of conventional individual prospective is a must for an efficient solution on wireless video streaming. 

We design a content-aware adaptive retry (CAR) mechanism for video streaming over 802.11 wireless LAN environments. CAR considers the error propagation characteristics as well as video play-out schedule so as to improve user-perceived video quality. The CAR-aided MAC can improve wireless  video streaming significantly.

Rate adaptation (RA) to dynamically adjust data rate during transmission has improved channel throughput on wireless networks. However, conventional RA algorithms try to solve this problem by maximize channel throughput in a saturate manner, rather than consider the characteristics of data. For video streaming applications, RA has to account for the delay sensitive property and adapt accordingly. Here we propose an advanced RA algorithm for wireless video streaming so as to take advantage of frame dependency and avoid outdated packets.

We implement a cross-layer optimized real-time H.263 video decoder/player on Linux platform. The Prism2 hostap driver is modified to support the content-aware adaptive retry feature. The collaboration of application and link layer demonstrate a better visual quality in bandwidth-limited, error-prone wireless environment.  

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Content-aware Adaptive Retry for Video Streaming on 802.11 WLANs

Robust video streaming over wireless LAN (WLAN) poses many challenges. In order to maximize channel throughput, rate adaptation (RA) to dynamically select the transmission rate at a given time has been recognized as an effective way to improve the performance of 802.11 WLANs. However, extra retransmission for channel probing during RA also causes additional delay and possible packet loss. For video streaming, we believe this overhead should be placed on less important packets so as to minimize quality distortion on the receiver side. We propose a content-aware adaptive retry mechanism for video streaming over 802.11 WLANs, where retry decision is made dynamically according to packet importance and its play-out schedule. Simulation results show that the proposed mechanism significantly improves video quality as well as saves transmission bandwidth. We also implement the above concept into a real system on Linux platform.

Please refer to the Content-aware Adaptive Retry on 802.11 WLANs for more details. 


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Journal Papers: 

Conference Papers: 

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March 18, 2006