Downstream time domian based adaptive modulation for DOCSIS based applications

• US 20040085976A1
• Filed: 12/12/2002
• Published: 05/06/2004
• Est. Priority Date: 11/06/2002
• Status: Active Grant

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Chien, Jen-Chieh (Jack), Kwentus, Alan, Jaffe, Steven, Dale, Mark, Hebsgaard, Anders, Lin, Dorothy, Wang, Joyce, Hartman, David, Gin, Alan, Brescia, Rocco, Cameron, Kelly, Krafft, Stephen
• Granted Patent: US 7,508,785 B2
• Time in Patent Office: Days
• US Class Current: 370/411
• CPC Class Codes: H04B 7/18582 Arrangements for data linking, i.e. for data framing, for error recovery, for multiple access
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/263 Rate modification at the source after receiving feedback
• CPC Class Codes: H04L 47/29 using a combination of thresholds
• CPC Class Codes: H04N 2007/17381 the upstream transmission being initiated by the user terminal
• CPC Class Codes: H04N 21/2383 Channel coding or modulation of digital bit-stream, e.g. QPSK modulation arrangements for detecting or preventing errors in the information received by adapting the channel coding H04L1/0009; analogue front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 21/2385 Channel allocation H04N21/266 takes precedence; Bandwidth allocation H04N21/24 takes precedence ; allocation of channels according to the instantaneous demands of the users in time-division multiplex systems H04J3/1682; admission control, resource allocation in open networks H04L12/5692; arrangements for maintenance or administration in data switching networks involving bandwidth and capacity management H04L41/0896; negotiating bandwidth in wireless networks H04W28/16
• CPC Class Codes: H04N 21/4382 Demodulation or channel decoding, e.g. QPSK demodulation analog front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 21/44209 Monitoring of downstream path of the transmission network originating from a server, e.g. bandwidth variations of a wireless network arrangements for maintenance or administration in data switching networks involving bandwidth and capacity management H04L41/0896
• CPC Class Codes: H04N 21/6143 involving transmission via a satellite
• CPC Class Codes: H04N 21/6193 involving transmission via a satellite arrangements for data linking, networking or transporting, or for controlling an end to end session in a satellite broadcast system H04B7/18526
• CPC Class Codes: H04N 21/6377 directed to server one-way streaming services wherein the source is controlled by the destination H04L65/613

Abstract

In a DOCSIS based satellite gateway data is transmitted over a single downstream channel, at different throughput rates. Data destined for each subscriber/receiver is assigned a throughput rate depending upon the downstream signal quality of that subscriber/receiver. To accomplish this, the downstream DOCSIS MAC data is parsed to extract DOCSIS packets. The DOCSIS packets are then loaded into packet queues based on an identifier within such packets such as the MAC destination address or SID. Each of the queues represents a bandwidth efficiency or throughput rate that can be currently tolerated by specific subscribers based on the current signal quality being experienced at the subscriber location. A PHY-MAP describing the downstream data structure to be transmitted and inserted into the downstream data. Data is extracted from the packet queues in queue blocks as defined by the PHY-MAP. The queue blocks are modulated with transmission parameters appropriate for each queue block and transmitted to the DOCSIS based satellite modems. The satellite modems extract the PHY-MAP from the downstream data and use the information contained in it to demodulate and decode the queue for which they have sufficient downstream signal quality. Satellite modems measure and transmit downstream signal quality to the satellite gateway to be used to assigned traffic to the appropriate queues.

Claims

1. A method of adaptively controlling the throughput rate of data traffic destined for each of a plurality of receivers, the data traffic combined into a single data stream and transmitted over a single downstream channel, said method comprising:

assigning data traffic for each of the receivers to a throughput rate based on downstream signal quality information for each of the receivers;

associating each of a plurality of packet queues with one of the plurality of throughput rates,

establishing a plurality of profiles for each of the packet queues, each of the profiles comprising a modulation type and an error correction encoding rate that supports the throughput rate;

parsing the data stream into the plurality of packet queues based on said assigning;

modulating and encoding the parsed data traffic in each of the packet queues in accordance with the associated profile; and

transmitting the modulated and encoded data traffic from each of the packet queues over the downstream channel.

2. The method of claim 1 wherein the signal quality information is the signal-to-noise ratio for the receiver.

3. The method of claim 1 wherein the signal quality information is the packet error rate for the receiver.

4. The method of claim 1 further comprising receiving the signal quality information from each of the plurality of receivers over an upstream signal channel.

5. The method of claim 1 wherein said assigning further comprises placing a packet queue identifier in each traffic packet of the data stream.

6. The method of claim 1 wherein said assigning further comprises assigning the data traffic destined for one of the plurality of receivers to any one or more throughput rates that are supported by the signal quality information of the receiver.

7. The method of claim 1 wherein the description of the downstream data structure are stored in PHY-MAPs, said method further comprising transmitting the PHY-MAPs to each of the receivers over the downstream channel, wherein the description of the downstream data structure includes all information necessary for the plurality of receivers to demodulate and decode the modulated and encoded data traffic.

8. The method of claim 7 wherein said transmitting the PHY-MAP further comprises assigning the PHY-MAP to the lowest throughput rate.

9. The method of claim 1 further comprising:

generating the data stream in accordance with a DOCSIS MAC layer, and

assigning DOCSIS MAC management messages and DOCSIS time stamp messages to the lowest throughput rate.

10. The method of claim 9 further comprising:

extracting packet data from the packet queues; and

framing the extracted packets in accordance with the profile stored in the PHY_MAP for each queue from which the data is extracted and framed.

11. The method of claim 10 wherein said modulating and encoding further comprises generating modulation and encoding control signals for each burst from a queue in accordance with the profile associated with the queue from which the framed data was extracted.

12. The method of claim 11 further comprising updating the PHY-MAP periodically to reflect changing downstream signal quality information.

13. The method of claim 1 wherein the profile for each packet queue includes information selected from the group consisting of modulation type, FEC type, FEC rate, FEC block size, queue block size, and a number of MPEG frames per queue block.

14. The method of claim 13 further comprising dynamically allocating time for transmission from each queue to optimize overall system throughput by altering the number of blocks and the number of MPEG frames per block.

15. A method for adaptively modulating data traffic comprising a data stream, said method comprising:

parsing the data stream into a plurality of packet queues;

establishing a plurality of profiles for each of the packet queues, each of the profiles comprising a modulation type and an error correction encoding rate;

extracting packet data from the packet queues;

framing the extracted packets in accordance with the profile associated with the queue from which the packet is extracted; and

modulating and encoding the parsed data traffic in each of the packet queues in accordance with the associated profile.

16. An apparatus for adaptively controlling the throughput rate of data traffic destined for each of a plurality of receivers, the data traffic combined into a single data stream and transmitted over a single downstream channel, said apparatus comprising:

means for assigning data traffic for each of the receivers to a throughput rate based on downstream signal quality information for each of the receivers;

means for associating each of a plurality of packet queues with one of the plurality of throughput rates,

means for establishing a plurality of profiles for each of the packet queues, each of the profiles comprising a modulation order and an error correction encoding rate that supports the throughput rate;

means for parsing the data stream into the plurality of packet queues based on said assigning;

means for modulating and encoding the parsed data traffic in each of the packet queues in accordance with the associated profile; and

means for transmitting the modulated and encoded data traffic from each of the packet queues over the downstream channel.

17. The apparatus of claim 16 wherein the signal quality information is the signal-to-noise ratio for the receiver.

18. The apparatus of claim 16 wherein the signal quality information is the packet error rate for the receiver.

19. The apparatus of claim 16 further comprising means for receiving the signal quality information from each of the plurality of receivers over an upstream signal channel.

20. The apparatus of claim 16 wherein said means for assigning further comprises means for placing a packet queue identifier in each traffic packet of the data stream.

21. The apparatus of claim 16 wherein said means for assigning further comprises means for assigning the data traffic destined for one of the plurality of receivers to any one or more throughput rates that are supported by the signal quality information of the receiver.

22. The apparatus of claim 16 wherein the associated profiles are stored in a PHY-MAP, said apparatus further comprising means for transmitting the PHY-MAP to each of the receivers over the downstream channel.

23. The apparatus of claim 22 wherein said means for transmitting the PHY-MAP further comprises means for assigning the PHY-MAP to the lowest throughput rate.

24. The apparatus of claim 16 further comprising:

means for generating the data stream in accordance with a DOCSIS MAC layer, and

means for assigning DOCSIS MAC management messages and DOCSIS time stamp messages to the lowest throughput rate.

25. The apparatus of claim 16 further comprising:

means for extracting packet data from the packet queues; and

means for framing the extracted packets in accordance with the profile stored in the PHY_MAP for each queue from which the data is extracted and framed.

26. The apparatus of claim 25 wherein said means for modulating and encoding further comprises means for generating modulation and encoding control signals for each frame in accordance with the profile associated with the queue from which the framed data was extracted.

27. The apparatus of claim 26 further comprising means for updating the PHY-MAP based on periodically to reflect changing downstream signal quality information.

28. The apparatus of claim 16 wherein the profile for each packet queue further comprises start times for bursts from each queue.

29. The apparatus of claim 28 further comprising means for dynamically allocating time for transmission from each queue to optimize overall system throughput.

30. An apparatus for adaptively modulating data traffic comprising a data stream, said apparatus comprising:

means for parsing the data stream into a plurality of packet queues;

means for establishing a plurality of profiles for each of the packet queues, each of the profiles comprising a modulation order and an error correction encoding rate;

means for extracting packet data from the packet queues;

means for framing the extracted packets in accordance with the profile associated with the queue from which the packet is extracted; and

means for modulating and encoding the parsed data traffic in each of the packet queues in accordance with the associated profile.