System and method for improving compression on a telephone loop

• US 6,539,016 B2
• Filed: 06/12/2001
• Issued: 03/25/2003
• Est. Priority Date: 06/12/2000
• Status: Expired due to Term

• Current Assignee: Ciena Corporation
• Original Assignee: Catena Networks, Inc. (Ciena Corporation)
• Inventors: Kumar, Yatish
• Primary Examiner(s): Ton, Dang
• Assistant Examiner(s): HOM, SHICK C
• Application Number:
  US09/872,259
• Publication Number:
  US 20020015410A1
• Time in Patent Office: 651 Days
• Field of Search: 370/259, 370/395.1, 370/395.2, 370/395.21, 370/395.52, 370/396, 370/397, 370/398, 370/399, 370/401, 370/402, 370/403, 370/404, 370/465, 370/468, 370/203, 370/395.61, 370/536, 370/538
• US Class Current: 370/395.1
• CPC Class Codes: H04L 47/17 Interaction among intermediate nodes, e.g. hop by hop
• CPC Class Codes: H04L 47/26 using explicit feedback to the source, e.g. choke packets
• CPC Class Codes: H04L 47/30 in combination with information about buffer occupancy at either end or at transit nodes
• CPC Class Codes: H04L 69/04 Protocols for data compression, e.g. ROHC

Abstract

An asymmetric digital subscriber line (ADSL) termination unit, which at the transmission end includes a descrambler and a compressor between its scrambler and interleaver. The present invention provides for the use of compression on the data in a channel to remove some of the inherent redundancy, in order to yield much better throughput, particularly in conjunction with certain powerful forward error correction (FEC) schemes. In this manner the compression may be performed on unscrambled data that has a higher redundancy than scrambled data, thereby improving compression. At the reception end, the ADSL termination unit includes a decompressor and a scrambler between its deinterleaver and descrambler.

Claims

1. A digital subscriber line (DSL) termination unit comprising:

an asynchronous transfer mode (ATM) transmission convergence circuit operative to perform transmission convergence on first ATM data to generate second ATM data;

a scrambler circuit operative to create scrambled second ATM data from said second ATM data;

a descrambler circuit operative to create descrambled second ATM data from said scrambled second ATM data;

a compression circuit operative to create compressed second ATM data from said descrambled second ATM data;

an interleaver circuit operative to create interleaved second ATM data from said compressed second ATM data prior to transmission; and

a control circuit operative to control said descrambler circuit and said compression circuit, wherein said control circuit controls said descrambler circuit and said compression circuit to limit a maximum compression bandwidth.

2. The DSL termination unit of claim 1, wherein said DSL termination unit is a central office DSL termination unit, said first ATM data is received from a network, and said second ATM data is transmitted to a subscriber.

3. The DSL termination unit of claim 1, wherein said DSL termination unit is a remote DSL termination unit, said first ATM data is received from a customer premises equipment, and said second ATM data is transmitted to a central office.

4. The DSL termination unit of claim 1, wherein said DSL termination unit has a fast path and an interleaved path, and the descrambling and the compressing are performed on said interleaved path.

5. A digital subscriber line (DSL) termination unit comprising:

an asynchronous transfer mode (ATM) transmission convergence circuit operative to perform transmission convergence on first ATM data to generate second ATM data;

a scrambler circuit operative to create scrambled second ATM data from said second ATM data;

a descrambler circuit operative to create descrambled second ATM data from said scrambled second ATM data;

a compression circuit operative to create compressed second ATM data from said descrambled second ATM data;

an interleaver circuit operative to create interleaved second ATM data from said compressed second ATM data prior to transmission; and

a control circuit operative to control said descrambler circuit and said compression circuit, wherein said control circuit controls said descrambler circuit and said compression circuit to limit an average compression bandwidth.

6. The DSL termination unit of claim 5, wherein said DSL termination unit is a central office DSL termination unit, said first ATM data is received from a network, and said second ATM data is transmitted to a subscriber.

7. The DSL termination unit of claim 5, wherein said DSL termination unit is a remote DSL termination unit, said first ATM data is received from a customer premises equipment, and said second ATM data is transmitted to a central office.

8. The DSL termination unit of claim 5, wherein said DSL termination unit has a fast path and an interleaved path, and the descrambling and the compressing are performed on said interleaved path.

9. A digital subscriber line (DSL) termination unit comprising:

an asynchronous transfer mode (ATM) transmission convergence circuit operative to perform transmission convergence on first ATM data to generate second ATM data;

a scrambler circuit operative to create scrambled second ATM data from said second ATM data;

a descrambler circuit operative to create descrambled second ATM data from said scrambled second ATM data;

a compression circuit operative to create compressed second ATM data from said descrambled second ATM data;

an interleaver circuit operative to create interleaved second ATM data from said compressed second ATM data prior to transmission; and

a control circuit operative to control said descrambler circuit and said compression circuit, wherein said control circuit controls said descrambler circuit and said compression circuit to perform compression on selected links and to refrain from performing compression on other links.

10. The DSL termination unit of claim 9, wherein said DSL termination unit is a central office DSL termination unit, said first ATM data is received from a network, and said second ATM data is transmitted to a subscriber.

11. The DSL termination unit of claim 9, wherein said DSL termination unit is a remote DSL termination unit, said first ATM data is received from a customer premises equipment, and said second ATM data is transmitted to a central office.

12. The DSL termination unit of claim 9, wherein said DSL termination unit has a fast path and an interleaved path, and the descrambling and the compressing are performed on said interleaved path.

13. A digital subscriber line (DSL) termination unit comprising:

an asynchronous transfer mode (ATM) transmission convergence circuit operative to perform transmission convergence on first ATM data to generate second ATM data;

a scrambler circuit operative to create scrambled second ATM data from said second ATM data;

a descrambler circuit operative to create descrambled second ATM data from said scrambled second ATM data;

a compression circuit operative to create compressed second ATM data from said descrambled second ATM data;

an interleaver circuit operative to create interleaved second ATM data from said compressed second ATM data prior to transmission; and

a control circuit operative to control said descrambler circuit and said compression circuit, wherein said control circuit controls said descrambler circuit and said compression circuit to limit a flow of ATM cells according to a fullness of a buffer space.

14. The DSL termination unit of claim 13, wherein said DSL termination unit is a central office DSL termination unit, said first ATM data is received from a network, and said second ATM data is transmitted to a subscriber.

15. The DSL termination unit of claim 13, wherein said DSL termination unit is a remote DSL termination unit, said first ATM data is received from a customer premises equipment, and said second ATM data is transmitted to a central office.

16. The DSL termination unit of claim 13, wherein said DSL termination unit has a fast path and an interleaved path, and the descrambling and the compressing are performed on said interleaved path.

17. A digital subscriber line (DSL) termination unit comprising:

an asynchronous transfer mode (ATM) transmission convergence circuit operative to perform transmission convergence on first ATM data to generate second ATM data;

a scrambler circuit operative to create scrambled second ATM data from said second ATM data;

a descrambler circuit operative to create descrambled second ATM data from said scrambled second ATM data;

a compression circuit operative to create compressed second ATM data from said descrambled second ATM data;

an interleaver circuit operative to create interleaved second ATM data from said compressed second ATM data prior to transmission; and

a control circuit operative to control said descrambler circuit and said compression circuit, wherein said control circuit controls said descrambler circuit and said compression circuit to apply a selected one or more of a plurality of compression algorithms according to a type of said first ATM data.

18. The DSL termination unit of claim 17, wherein said DSL termination unit is a central office DSL termination unit, said first ATM data is received from a network, and said second ATM data is transmitted to a subscriber.

19. The DSL termination unit of claim 17, wherein said DSL termination unit is a remote DSL termination unit, said first ATM data is received from a customer premises equipment, and said second ATM data is transmitted to a central office.

20. The DSL termination unit of claim 17, wherein said DSL termination unit has a fast path and an interleaved path, and the descrambling and the compressing are performed on said interleaved path.

21. A digital subscriber line (DSL) termination unit comprising:

an asynchronous transfer mode (ATM) transmission convergence circuit operative to perform transmission convergence on first ATM data to generate second ATM data;

a scrambler circuit operative to create scrambled second ATM data from said second ATM data;

a descrambler circuit operative to create descrambled second ATM data from said scrambled second ATM data;

a compression circuit operative to create compressed second ATM data from said descrambled second ATM data; and

an interleaver circuit operative to create interleaved second ATM data from said compressed second ATM data prior to transmission, wherein said DSL termination unit has a fast path and an interleaved path, and the descrambling and the compressing are performed on said interleaved path.

22. A digital subscriber line (DSL) termination unit for processing first asynchronous transfer mode (ATM) data, comprising:

a deinterleaver circuit operative to create deinterleaved first ATM data from said first ATM data;

a decompression circuit operative to create decompressed first ATM data from said deinterleaved first ATM data;

a scrambler circuit operative to create scrambled first ATM data from said decompressed first ATM data;

a descrambler circuit operative to create descrambled first ATM data from said scrambled first ATM data; and

an ATM transmission convergence circuit coupled to perform transmission convergence on said descrambled first ATM data to generate second ATM data prior to transmission, wherein said DSL termination unit has a fast path and an interleaved path, and the decompressing and the scrambling are performed on said interleaved path.

23. The DSL termination unit of claim 22, wherein said DSL termination unit is a central office DSL termination unit, said first ATM data is received from a subscriber, and said second ATM data is transmitted to a network.

24. The DSL termination unit of claim 22, wherein said DSL termination unit is a remote DSL termination unit, said first ATM data is received from a central office, and said second ATM data is transmitted to customer premises equipment.

25. A system for compressing asynchronous transfer mode (ATM) data on a digital subscriber line (DSL) link comprising:

a central office DSL termination unit including;

a first ATM transmission convergence circuit operative to perform transmission convergence on first ATM data to generate second ATM data,

a first scrambler circuit operative to create scrambled second ATM data from said second ATM data,

a first descrambler circuit operative to create descrambled second ATM data from said scrambled second ATM data,

a compression circuit operative to create compressed second ATM data from said descrambled second ATM data, and

an interleaver circuit operative to create interleaved second ATM data from the compressed second ATM data prior to transmission to a subscriber via said ADSL link, wherein said central office DSL termination unit has a fast path and an interleaved path, and the descrambling and the compressing are performed on said interleaved path; and

a remote DSL termination unit including;

a deinterleaver circuit operative to create deinterleaved second ATM data from said interleaved second ATM data received from a central office via said ADSL link,

a decompression circuit operative to create decompressed second ATM data from said deinterleaved second ATM data,

a second scrambler circuit operative to create scrambled second ATM data from said decompressed second ATM data,

a second descrambler circuit operative to create descrambled second ATM data from said scrambled second ATM data, and

a second ATM transmission convergence circuit coupled to perform transmission convergence on said descrambled second ATM data to generate third ATM data prior to transmission to customer premises equipment.