End-to-End TCP-Friendly Streaming Protocol and Bit Allocation for Scalable Video Over Wireless Internet

Fan Yang, Qian Zhang, Wenwu Zhu, and Ya-Qin Zhang

IEEE Journal on Selected Areas in Communications, May 2004

Outline Introduction Design issues

Packet loss Delay variation TCP-friendly

WMSTFP Estimation of network conditions End-to-end rate distortion

Simulation results

Video streaming over wireless Internet

Design issues of streaming over wireless Internet The end-to-end packet loss can be caused by

the congestion loss occurred in the wired network the erroneous loss occurred in the wireless

network The variation in end-to-end delay is large.

Packet loss ratio and round-trip time (RTT) is usually used by streaming protocol to adjust sending rate.

The streaming protocol should be friendly to TCP.

System architecture (1/2)

System architecture (2/2) WMSTFP congestion control (sender)

Adjust sending rate based on the feedback information.

WMSTFP network monitor (receiver) Analyze the erroneous loss rate (wireless) and

congestive loss rate (wired). Estimate the end-to-end available network

bandwidth. Network-adaptive ULP channel encoder

Protect different layers of PFGS according to their importance and network status using RS codes.

Loss differentiated R-D-based bit allocation Make the total sending rate adapt to the estimated

network conditions.

Features of WMSTFP Accurate loss differentiation

Detect packet losses caused by the erros in wireless channels using the information acquire at the link-layer.

Forward loss ratio estimation Packets have different loss patterns. (different l

oss burtiness lengths)

Smoothed RTT measurement

Overview of the protocol The process of the protocol:

estimating loss rate (congestive and erroneous); estimating RTT and retransmission time out

(RTO); estimating the available network bandwidth and

adjusting the sending rate.

After slow-start, the sender adjusts its sending rate based on the congestive packet loss ratio, RTT, and RTO.

RTT measurement

RTT and RTO estimation (1/2)

is set to 0.75

avoid the clock synchronization issue

RTT and RTO estimation (2/2)

k is set to 4

roundlast in the RTT estimated theis RTT

RTT of variation theof estimation smoothed theis RTTVAR

RTT. estimatedcurrent theis RTT

'

is set to 0.25

End-to-end packet loss differentiation and measurement Use the link-layer information to differentiate the

wireless erroneous loss and congestive loss.

In the third-generation (3G) wireless communication system, we can deduce a packet loss caused by wireless errors based on the information provided in the radio link control layer (RLC).

We can even get more detailed statistical information such as frame error rate at the radio resource control layer (RRC).

Network-adaptive ULP Applying ULP scheme to different layer to

provide prioritized transmission.

When the network is in good status, more bit budget should be assigned for source coding and fewer bits should be assigned for channel coding.

On the contrary, when network condition is bad, it is necessary to allocate more bits for channel coding, thus fewer bits should be allocated for source coding.

Loss patterns (1/3)

Loss patterns (2/3)

Different loss patterns have different impact on the perceived QoS quality in video streaming.

Loss patterns (3/3)

Comparisons of the 55th reconstructed frame under different schemes.

Assume the loss pattern is randomly distributed.

End-to-end rate distortion

DT: end-to-end distortion

Ds: source distortion (caused by quantization & rate control)

Dc: channel distortion (caused by packet loss)

Rs: source coding rate

Rc: channel coding rate

Problem formulation (1/2) Allocate the available bit rate such that the optima

l Rs and Rc are obtained by minimizing end-to-end distortion under the constraint Rs + Rc ≤ RT. (RT is the estimated network bandwidth)

Problem formulation (2/2)

Pc, layer(i, j) is the probability that the jth packet in the ith layer is lost due to congestion.

Pw, layer(i, j) is the probability that the jth packet in the ith layer is lost due to wireless errors.

not congested & wireless error

Simulation topology

Comparisons of throughput for TCP and WMSTFP connections

Why TCP is better than WMSTFP?

Sending rate comparisons of WMSTFP and TCP

FER = 0.1

Throughput comparisons under different FER

FER = 0.2 FER =

0.3

Why WMSTFP is now better than TFRC?

TFRC (TCP-friendly rate control protocol)

Overall packet loss rate under different FER

TFRC has the higher loss rate.

TCP has the higher throughput?

Performance of loss differentiated R-D-based bit allocation scheme

FULP-T fixed ULP without loss pattern

differentiation over TFRC FULP-W

fixed ULP without loss pattern differentiation over WMSTFP

AULP-W adaptive ULP over WMSTFP

Average PSNR of different schemes under different bit rates

FER = 0.3FER = 0.2

Average PSNR comparisons for foreman using different schemes

FER = 0.3

FER = 0.2

PSNR comparisons for foreman using different schemes

FER = 0.3

FER = 0.2

Comparison of the reconstructed frames under different FERs (1/3)

FER = 0.3

FER = 0.2

AULP-W

Comparison of the reconstructed frames under different FERs (2/3)

FER = 0.3

FER = 0.2

FULP-W

Comparison of the reconstructed frames under different FERs (3/3)

FER = 0.3

FER = 0.2

FULP-T