Adaptive estimation method of multimedia data transmission rate in a data communication system

• US 20060018257A1
• Filed: 07/20/2005
• Published: 01/26/2006
• Est. Priority Date: 07/23/2004
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Seo, Kwang-Deok
• Granted Patent: US 7,746,780 B2
• Time in Patent Office: Days
• US Class Current: 370/232
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/12 Avoiding congestion; Recovering from congestion
• CPC Class Codes: H04L 47/2416 Real-time traffic
• CPC Class Codes: H04L 47/263 Rate modification at the source after receiving feedback

Abstract

A method for adaptively estimating a transmission rate of multimedia data by monitoring an RTCP network state is provided. The method comprises receiving a real-time transport protocol (RTCP) receiver report packet from a multimedia data reception unit; detecting packet loss rate from the RTCP receiver report packet; and adaptively estimating an available transmission rate according to a range within which the packet loss rate belongs.

Claims

1. An adaptive estimation method of multimedia data transmission rate, the method comprising:

receiving a real-time transport protocol (RTCP) receiver report packet from a multimedia data reception unit;

detecting packet loss rate from the RTCP receiver report packet; and

adaptively estimating an available transmission rate according to a range within which the packet loss rate belongs.

2. The method of claim 1, wherein the available transmission rate is estimated according to a range within which the packet loss rate belongs.

3. The method of claim 1, wherein the estimating step comprises:

estimating the available transmission rate according to a first equation, when the packet loss rate is in a first range;

estimating the available transmission rate according to a second equation, when the packet loss rate is in a second range; and

estimating the available transmission rate according to a third equation, when the packet loss rate is in a third range.

4. The method of claim 3, wherein the first equation is:

$R_1<br><br>\left(p<br><br>\left(t_n\right)\right)=\frac{1.22\times <br><br>s}{\mathrm{RTT}<br><br>\left(t_n\right)\times <br><br>\sqrt{p<br><br>\left(t_n\right)}},$

S=packet size,

RTT(t_n)=Round-Trip delay Time, and

P(t_n)=packet loss rate detected from n^th RTCP receiver report (RR) packet.

5. The method of claim 3, wherein the second equation is:

$R_2<br><br>\left(p<br><br>\left(t_n\right)\right)=\frac{s\times <br><br>20\times <br><br>\left(1-\mathrm{\alpha <br><br>}\times <br><br>p<br><br>\left(t_n\right)\right)}{\mathrm{LSR}<br><br>\left(t_n\right)-\mathrm{LSR}<br><br>\left(t_{n-1}\right)}+\mathrm{\beta <br><br>},$

S=packet size,

P(t_n)=packet loss rate detected from n^th RTCP receiver report (RR) packet

LSR(t_n)=transmission time of n^th RTCT sender report (SR) packet, and

α

,β

=weight factors.

6. The method of claim 3, wherein the third equation is based on a minimum transmission rate assigned by a user.

7. The method of claim 3, wherein the first range is approximately 5% or less.

8. The method of claim 3, wherein the second range is between approximately 5% and approximately 10%.

9. The method of claim 3, wherein the third range is approximately 10% or more.

10. The method of claim 1, wherein one RTCP sender report packet is transmitted every time a predetermined number of RTP packets are transmitted.

11. The method of claim 1, wherein one RTCP receiver report packet is received, every time a predetermined number of RTP packets are transmitted.

12. The method of claim 10, wherein the predetermined number is approximately 20.

13. The method of claim 11, wherein the predetermined number is approximately 20.

14. The method of claim 10, wherein the RTCP receiver report packet comprises:

a reception report block for reporting to multimedia data transmission unit statistical information of RTP packets transmitted from the multimedia data transmission unit.

15. The method of claim 14, wherein the reception report block comprises a packet loss rate and a transmission time of the last RTCP sender report packet.

16. A transmission unit for adaptively estimating a transmission rate of multimedia data in an RTCP network, the transmission unit comprising:

a compression domain comprising;

a video encoder; and

a video compression unit in communication with the video encoder;

a transport domain comprising;

a transmission rate control unit;

a RTP layer supporting communication with the transmission control unit;

a UDP layer supporting communication with the RTP layer; and

an IP layer supporting communication with the UDP layer over the IP layer, wherein;

the transmission unit receives a real-time transport protocol (RTCP) receiver report packet from a multimedia data reception unit, detects packet loss rate from the RTCP receiver report packet; and

adaptively estimates an available transmission rate according to a range within which the packet loss rate belongs.

17. The transmission unit of claim 16 wherein the available transmission rate is adaptively estimated according to:

$R<br><br>\left(t_n\right)\equiv <br><br>\{\begin{array}{cc}{R}_1<br><br>\left(p<br><br>\left(t_n\right)\right)=\frac{1.22\times <br><br>s}{\mathrm{RTT}<br><br>\left(t_n\right)\times <br><br>\sqrt{p<br><br>\left(t_n\right)}}& \left(p<br><br>\left(t_n\right)\le <br><br>1<br><br>\mathrm{st}.\mathrm{Threshold}\right)\\ R_2<br><br>\left(p<br><br>\left(t_n\right)\right)=\frac{s\times <br><br>20\times <br><br>\left(1-\mathrm{\alpha <br><br>}\times <br><br>p<br><br>\left(t_n\right)\right)}{\mathrm{LSR}<br><br>\left(t_n\right)-\mathrm{LSR}<br><br>\left(t_{n-1}\right)}+\mathrm{\beta <br><br>}& \left(1<br><br>\mathrm{st}.\mathrm{Threshold}<<br><br>p<br><br>\left(t_n\right)<<br><br>2<br><br>\mathrm{nd}.\mathrm{Threshold}\right)\\ R_3<br><br>\left(p<br><br>\left(t_n\right)\right)=\mathrm{MinimumRate}<br><br>\text{\hspace{1em}<br><br>}<br><br>\left(\mathrm{ex}<br><br>\mathrm{.50}<br><br>\mathrm{kbps}\right)& \left(p<br><br>\left(t_n\right)><br><br>2<br><br>\mathrm{nd}.\mathrm{Threshold}\right)\end{array}$

wherein;

S=packet size,

P(t_n)=packet loss rate detected from n^th RTCP receiver report (RR) packet

LSR(t_n)=transmission time of n^th RTCT sender report (SR) packet, and

α

, β

=weight factors.

18. The transmission unit of claim 17, wherein the first threshold is approximately 5%.

19. The transmission unit of claim 17, wherein the second threshold is approximately 10%.

20. The transmission unit of claim 17, wherein the first threshold is 5% and the second threshold is 10%.