Cable modem system and method for supporting packet PDU compression

• US 7,275,115 B2
• Filed: 10/11/2001
• Issued: 09/25/2007
• Est. Priority Date: 10/11/2000
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Johnson, Thomas L, Bunn, Fred A
• Primary Examiner(s): Flynn; Nathan
• Assistant Examiner(s): Joo; Joshua
• Application Number:
  US09/973,783
• Publication Number:
  US 20020049861A1
• Time in Patent Office: 2,175 Days
• Field of Search: 709/246, 709/247, 341/51, 375/240
• US Class Current: 709/247
• CPC Class Codes: H03M 7/30 Compression speech analysis-synthesis for redundancy reduction G10L19/00; for image communication H04N; Expansion; Suppression of unnecessary data, e.g. redundancy reduction
• CPC Class Codes: H03M 7/3088 employing the use of a dictionary, e.g. LZ78
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/65 Network streaming protocols, e.g. real-time transport protocol [RTP] or real-time control protocol [RTCP]
• CPC Class Codes: H04L 65/70 Media network packetisation
• CPC Class Codes: H04L 65/765 intermediate
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04L 69/04 Protocols for data compression, e.g. ROHC
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/161 Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04N 21/437 Interfacing the upstream path of the transmission network, e.g. for transmitting client requests to a VOD server flow control in data networks H04L47/10; streaming protocols, e.g. RTP or RTCP, H04L65/65; scheduling or organising the servicing of application requests in data packet switching networks H04L67/60
• CPC Class Codes: H04N 21/4622 Retrieving content or additional data from different sources, e.g. from a broadcast channel and the Internet web site content organization and management for information retrieval from the Internet G06F16/958; transmission by internet of broadcast information H04H60/82; stock exchange data over packet-switching network H04L12/1804; push services including data channel over packet-switching network H04L12/1859
• CPC Class Codes: H04N 21/4782 Web browsing , e.g. WebTV
• CPC Class Codes: H04N 21/6332 directed to client
• CPC Class Codes: H04N 21/6402 Address allocation for clients address allocation in data networks H04L61/50
• CPC Class Codes: H04N 21/64322 IP
• CPC Class Codes: H04N 21/6437 : Real-time Transport Protocol [RTP]
• CPC Class Codes: H04N 7/17336 : Handling of requests in head-ends
• CPC Class Codes: H04W 28/06 : Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365

Abstract

A cable modem system and method are provided for using a data compression dictionary to transmit compressed payload data in a DOCSIS network while utilizing conventional cable modem termination system (CMTS) equipment. A cable modem system in accordance with the invention includes a cable modem and a CMTS adapted to send and receive compressed payload data. In one example, the cable modem is adapted to compress PDU payload data using a data compression dictionary and the CMTS is adapted to reconstruct the compressed PDU payload data that is received from the cable modem.

Claims

1. A method for generating a data compression dictionary and utilizing it to enhance communication efficiency in a DOCSIS compliant network, comprising the steps of:

i. identifying a plurality of frequently occurring data strings transmitted by a plurality of cable modems in the DOCSIS network;

ii. assigning a token to represent each one of the plurality of frequently occurring data strings;

iii. entering each one of the plurality of frequently occurring data strings and each token assigned to represent each one of the plurality of frequently occurring data strings into a lookup table to produce a data compression dictionary; and

iv. transmitting the data compression dictionary to the plurality of cable modems in the DOCSIS network during initialization of each of the plurality of cable modems.

2. The method of claim 1, further comprising repeating steps i.-iv. for each of a plurality of DOCSIS networks, thereby generating a plurality of data compression dictionaries, each of which is individually tuned for a corresponding one of the plurality of DOCSIS networks.

10. The method of claim 1, further comprising:

v. updating the data compression dictionary; and

vi. transmitting the updated data compression dictionary to each modem of the plurality of cable modems in the DOCSIS network.

11. The method of claim 1, further comprising:

v. transmitting the data compression dictionary to a new cable modem responsive to the new cable modem being connected to the DOCSIS network.

3. A method for transmitting compressed data packets in a DOCSIS network, comprising the steps of:

i. receiving a plurality of data packets for transmission, wherein each of said data packets has a payload portion comprised of one or more data strings;

ii. identifying which of said data packets has a payload portion that can be compressed;

iii. for each of said data packets identified in said step (b), replacing each of said one or more data strings contained in said payload portion with a token from a data compression dictionary assigned to represent said one or more data strings, wherein said data compression dictionary is tuned to data transmitted by a plurality of cable modems on the DOCSIS network;

iv. appending a compression indicator to each of said tokens within each of said data packets; and

v. transmitting said data packets within a DOCSIS service identifier; and

vi. transmitting said data dictionary to each cable modem on the DOCSIS network when each said cable modem is initialized.

4. The method of claim 3 wherein the token is a binary string.

5. The method of claim 4 wherein the compression indicator indicates the length of the binary string.

6. The method of claim 3 wherein said data compression dictionary is pre-defined and fixed.

7. A method for expanding a PDU data string transmitted over a DOCSIS network, comprising the steps of:

i. receiving a plurality of data packets transmitted within a DOCSIS service identifier, wherein each of said data packets has a payload portion;

ii. identifying each of said plurality of data packets having a compression indicator appended to one or more tokens within said payload portion; and

iii. for each of said data packets identified in said step (b), replacing each of said one or more tokens contained within said payload portion with a data string assigned to represent said one or more tokens found in a data compression dictionary, wherein said data compression dictionary is tuned to data transmitted by a plurality of cable modems on the DOCSIS network and downloaded to each cable modem when it is initialized.

8. The method of claim 7, wherein the token is a binary string.

9. The method of claim 8, wherein the compression indicator identifies the length of the binary string.