Fan Yang, Qian Zhang, Member, IEEE, Wenwu Zhu, Senior Member, IEEE, and Ya-Qin Zhang, Fellow, IEEE Chungyong Cha

Fig. 1. General illustration of video 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

 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

 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 loss burtiness lengths)  Smoothed RTT measurement

 WMSTFP consists of a sender part and a receiv er part ◦ Estimating loss rate(congestive and erroneous) ◦ Estimating RTT and retransmission time out(RTO) ◦ Estimating the available network bandwidth and adjusting the sending rate.

 RTT=RTT wired +RTT wireless  RTT n =Ts′ n -Ts n -offset  RTT i ≈RTT n -2[(Tr n -Tr i )-(Ts n -Ts i )],(0≤i≤n-1)

 is the current estimated RTT  is the smoothed estimation of the variation of RTT  is the estimated RTTin the last round

 Use the link-layer information to differentiate the wireless erroneous loss and congestive loss.  In the 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 detailde statistical information such as frame error rate at the radio resource control layer(RRC)

 If(estrate>currate) else Rf:

 Applying ULP scheme to different layer to provide prioritized transmission  When the net work 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.

Protection ratios under different burst lengths

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

Fig. 6. Comparisons of the 55th reconstructed frame under different bit allocation schemes.

 D T =D s (R s )+D c (R s,R c )  D T :end-to-end distortion  D s :source distortion(caused by quantization& rate control)  D c :channel distortion(caused by packet loss)  R s :source coding rate  R c :channel coding rate

 Allocate the available bit rate such that the optimal R s and R c are obtained by minimizing end-to-end distortion under the constraint R s +R c ≤R r.

 D c (R s,R c )=D c,wired (R s,R c )+D c,wireless (R s,R c )

 Average throughput of WMSTFP&:TCP connection  Friendliness measure defined as  Note that the closer to 1 the value of F is,the frien- dlier WMSTFP is to TCP

Comparisons of throughput for TCP and WMSTFP connections.

 Variations of WMSTFP & TCP difined as:  The smoothness measure is then defined as:  S≤1means the ith WMSTFP is smoother than TCP

(a) FER = 0:1. (b) FER = 0:2. (c) FER = 0:3.

Table 1 OVERALL PACKET LOSS RATIO UNDER DIFFERENT FER

 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

(a)FER=0.3 (b)FER=0.2

FER=0.3 FER=0.2

(a)FER=0.3 (b)FER=0.2

(a)FER=0.3(b)FER=0.2 FULP-W FULP-T AULP-W

 The streaming protocol, WMSTFP, is proposed whic h is friendly to TCP in wired-line IP networks, and can achieve higher throughput than TCP-friendly in wirelessnetworks.  A loss differentiated R-D-based bit allocation sch- eme is further proposed by applying the network-a daptive ULP scheme.