Source adaptive digital subscriber line and method

• US 6,763,097 B1
• Filed: 04/12/2001
• Issued: 07/13/2004
• Est. Priority Date: 06/24/1999
• Status: Expired due to Term

• Current Assignee: Sigma Designs Israel S.D.I Ltd. (Uphill Investment Co.)
• Original Assignee: Coppergate Communications Limited (Sigma Designs Incorporated)
• Inventors: Vitenberg, Roman
• Primary Examiner(s): WOO, STELLA L
• Application Number:
  US09/720,724
• Time in Patent Office: 1,188 Days
• Field of Search: 379/93.08, 379/93.28, 379/93.31, 379/90.01, 379/93.01, 375/222
• US Class Current: 379/93.31
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways

Abstract

A communication system includes a plurality of subscribers having a telephone set and different types of home modems coupled using twisted pairs to a local server that includes a plurality of downstream repeaters, a central office coupled to a local server using twisted pair subscriber lines. The central office includes a telephone switch that provides telephone service to the subscribers and a concentrator that connects a plurality of upstream repeaters with a number of office modems that provide data service to the subscriber. A communication system uses CAP or DMT line signals with time division. The line signal transmits with different time framing. Every subscriber line can work in one of three operation modes Asymmetrical mode, Half-Asymmetrical mode, and Symmetrical mode. An office modem changes the operation mode of subscribers line and downstream/upstream bit rate depending on the type of an information source and the type of the subscriber home modem that is connected to the office modem in the current transmit cycle.

Claims

1. A central office of a digital subscriber line communication system, the central office comprising:

a telephone switch connectable to a plurality of subscriber lines; and

at least one office modem, each comprising;

a modem connectable to a subscriber line; and

a transmission frame generator to select a type of transmission frame at least in accordance with the type of information source currently active through a home modem connected to said office modem.

2. A central office according to claim 1 wherein said office modem additionally comprises a superframe unit which assigns a different transmission frame of a superframe to each of at least two of said home modems which are connected to said subscriber line.

3. A central office according to claim 1 wherein said office modem comprises a programming unit which programs each of at least two of said home modems which are connected to said subscriber line for communication with said central office modem or with another home modem.

4. A central office according to claim 1 wherein said office modem additionally comprises means for communicating with a digital telephone set connected to said subscriber line.

5. A central office according to claim 1 and also comprising a plurality of upstream repeaters coupled to twisted pair subscriber lines, each said upstream repeater comprising a unit which splits one said twisted pair subscriber line into a downstream data line, an upstream data line and a phone line.

6. An office transmission unit of a digital subscriber line communication system, the unit comprising:

a modem connectable to a subscriber line; and

a transmission frame generator to select a type of transmission frame at least in accordance with the type of information source currently active through a home modem connected to said office transmission unit.

7. A unit according to claim 6 wherein said office modem additionally comprises a superframe unit which assigns a different transmission frame of a superframe to each of at least two of said home modems which are connected to said subscriber line.

8. A unit according to claim 6 wherein said office modem comprises a programming unit which programs each of at least two of said home modems which are connected to said subscriber line for communication with said central office modem or with another home modem.

9. A unit according to claim 6 wherein said office modem additionally comprises means for communicating with a digital telephone set connected to said subscriber line.

10. A home modem of a digital subscriber line communication system, said home modem comprising:

a housing connectable to a plurality of information sources, said information sources being formed of the group comprising;

asymmetrical information sources, symmetrical information sources and half-asymmetrical information sources; and

a transmission frame generator to select a type of transmission frame at least in accordance with the type of information source currently connected to said housing.

11. A modem according to claim 10 and also comprising a home superframe unit which processes a transmission frame assigned to it by an office superframe unit.

12. A method for communication along telephone cables in a digital subscriber line communication system, the method comprising:

selecting a transmission frame structure depending on the type of information source that is connected to a subscriber line in a current communication session.

13. A method according to claim 12 wherein said frame structure has a fixed duration, divided into a downstream interval, an upstream interval and a gap interval and wherein the number of data transport cells in said downstream and upstream intervals depends on said type of information source.

14. A method according to claim 13 and wherein there are no data transport cells in the upstream interval for asymmetric information sources.

15. A method according to claim 13 and wherein there are fewer data transport cells in the upstream interval than in the downstream interval for half-asymmetric information sources.

16. A method according to claim 13 and wherein there are an equivalent number of data transport cells in the upstream and downstream intervals for symmetric information sources.

17. A method according to claim 12 and further comprising:

packing a number of transmission frames into a superframe;

assigning transmission frames of a superframe to different communication channels;

assigning to each communication channel two communication devices; and

sequential transmission of a number of transmission frames included into a superframe.

18. A method according to claim 13 and further comprising selecting the modulation of a data transport cell in accordance with the type of home modem that is connected to a subscriber line in said current communication session.

19. A method according to claim 12 and further comprising controlling of devices connected to a subscriber line by a control word of a downstream line signal.