Sunhun Lee and Kwangsue ChungSchool of Electronics Engineering,

Kwangwoon University22nd International Conference on Advanced

Information Networking and Application

Joint Quality and Rate Adaptation Scheme for

Wireless Video Streaming

OutlineIntroductionBackgroundCross-layer designPerformance evaluationConclusion

IntroductionThis paper proposed a new cross-layer

design for video streaming over wireless network that jointly considers the application and the lower layers(PHY and MAC) to imporve the wireless link utilization by adapting the data transmission to the current channel condition.

Quality adaptation scheme – ApplicationRate adaptation scheme – MAC and PHY

BackgroundIEEE 802.11 WLAN

DCF (Distributed Coordination Function) – CSMA/CAPCF (Point Coordination Function) – pollingetc…(RTS/CTS)IEEE 802.11 PHY provides multiple data transmission

modes. (ex.1, 2, 5.5 and 11 Mbps are support at 2.4GHz

ISM band in 802.11b)

BackgroundIEEE 802.11 WLANRate adaptation scheme

Higher data rate does not yield a higher throughput.Basic idea of these scheme have been proposed is

to estimate the channel quality and adjust the data transmission mode accordingly.

1. Statistics-basedMaintain statistics about the data delivery such as

the PER/BER (Packet Error Rate / Bit Error Rate). o ARF (Auto Rate Fallback)o CARA (Collision-Aware Rate Adapation)

2. Quality-basedMeasure SNR (Signal to Noise Ratio) or SSI (Signal

Strength Indicator).o RBAR (Receiver-Based Auto Rate)

Cross-layer designOverview

Cross-layer designOverviewRate adaptation scheme in our design

This paper proposed a new scheme, called SARA (Sender-oriented Automatic Rate Adaptation)

Quality-basedRTS frame is used when the size of pending data is

equal to or larger than the RTS threshold.RSSI (Received Signal Strength Indicator) instead of

SNR

Cross-layer designOverviewRate adaptation scheme in our design

Cross-layer designOverviewRate adaptation scheme in our designQuality adaptation scheme in our design

Rate limit is calculated based on the packet pair algorithm and periodically notified to the quality of video stream.

Quality adaptation scheme uses the hierarchical encoding scheme, specifically the FGS (Fine Granularity Scheme) algorithm of MPEG-4 standards determined sending rate.

This paper think that the hierarchical encoding scheme is not employed to streaming application because encoders with this capability are rare.

Performance evaluationNS-2BSS mode (Include AP and Stations)CBR (Constant Bit Rate) traffic at a rate

4MbpsSimulation time 50s

10-30 low speed30-40 medium speed40-50 high speed

Performance evaluation

Performance evaluation

Performance evaluation

Performance evaluation

Performance evaluation

Performance evaluation

Performance evaluation

Quality adaptation

ConclusionThis paper proposed a idea that combines

the rate adaptation with the quality adaptation for providing improved wireless video streaming service.

In future, they want to extend their design to the wired-cum-wireless convergence network environments.