Protocol for transceiver initialization

• US 6,249,543 B1
• Filed: 11/23/1999
• Issued: 06/19/2001
• Est. Priority Date: 06/20/1997
• Status: Expired due to Term

• Current Assignee: Amati Communications Corp. (Texas Instruments, Inc.)
• Original Assignee: Amati Communications Corp. (Texas Instruments, Inc.)
• Inventors: Chow, Jacky S.
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): GHAYOUR, MOHAMMAD H
• Application Number:
  US09/448,565
• Time in Patent Office: 574 Days
• Field of Search: 375/219, 375/222, 375/225, 375/260, 375/240, 370/468, 370/235, 370/236, 455/516, 379/93.08
• US Class Current: 375/219
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0046 Determination of how many bits are transmitted on different sub-channels
• CPC Class Codes: H04L 5/0094 Indication of how sub-channels of the path are allocated
• CPC Class Codes: H04L 5/1438 Negotiation of transmission parameters prior to communication modified according to link quality H04L1/0001

Abstract

Improved initialization techniques for initializing data transfer between a pair of transceivers in a multicarrier modulation transmission system are disclosed. The multicarrier modulation transmission system normally includes a central office and a remote unit, with the central office having at least one transceiver and the remote unit having a transceiver. For each pair of transceivers, the transceiver at either the central office or the remote unit controls the determining of bit allocations for both upstream and downstream data transmissions without assistance from the other transceiver of the pair. The initialization processing for the pair of transceivers is thus performed efficiently and with better centralized control.

Claims

1. A transceiver for a data transmission system using multicarrier modulation, said transceiver comprising:

a bit allocation table, said bit allocation table stores bit allocation information including separate bit allocation information for a plurality of carriers of the multicarrier modulation;

a data symbol encoder, said data symbol encoder receives digital data to be transmitted and encodes bits associated with the digital data onto the carriers based on the bit allocation information stored in said bit allocation table;

a multicarrier modulation unit, said multicarrier modulation unit modulates the encoded bits on the carriers to produce modulated signals;

a digital-to-analog converter, said digital-to-analog converter converts the modulated signals to analog signals; and

a controller, said controller performs initialization processing for said transceiver to set the bit allocation information in said bit allocation table, the initialization processing including the operations of;

determining channel and noise characteristics for data transmissions to said transceiver from a remotely located transceiver;

producing first direction performance information for data transmissions to said transceiver from the remotely located transceiver based on the channel and noise information;

receiving second direction performance information from the remotely located transceiver;

determining first direction bit allocations and second direction bit allocations, the first direction bit allocations being based on the first direction performance information and the second direction bit allocations being based on the second direction performance information; and

thereafter forwarding the first direction bit allocations and the second direction bit allocations from said transceiver to the remotely located transceiver.

2. A transceiver as recited in claim 1, wherein said controller determines both the first direction bit allocations and the second direction bit allocations without interaction with the remotely located transceiver.

3. A transceiver as recited in claim 1, wherein the first direction performance information is produced based on the channel and noise characteristics for data transmissions in the first direction.

4. A transceiver as recited in claim 1, wherein said modulation unit modulates the encoded bits on the frequency tones of a symbol using Discrete Multi Tone (DMT) modulation.

5. A transceiver as recited in claim 1,

wherein said bit allocation table is a superframe bit allocation table that stores bit allocation information for a superframe, the superframe having a plurality carriers in each of a plurality of frames, and

wherein said data symbol encoder allocates bits differently in the various frames of a superframe by using different portions of the superframe bit allocation information stored in said superframe bit allocation table.

6. A computer readable medium containing program instructions for initializing a pair of transceivers of a multicanier transmission system for subsequent transfer of data between the pair of transceivers over a link, said computer readable medium comprising:

computer readable code devices for producing, at the first transceiver of the pair of transceivers, first direction performance information for data transmissions in a first direction;

computer readable code devices for producing, at the second transceiver of the pair of transceivers, second direction performance information for data transmissions in a second direction;

computer readable code devices for forwarding the second direction performance information from the second transceiver to the first transceiver;

computer readable code devices for determining, at the first transceiver of the pair of transceivers, first direction bit allocations and second direction bit allocations, the first direction bit allocations being determined based on the first direction performance information and the second direction bit allocations being determined based on the second direction performance information; and

computer readable code devices for thereafter forwarding the first direction bit allocations and the second direction bit allocations from the first transceiver to the second transceiver.

7. A computer readable medium as recited in claim 6,

wherein said computer readable medium further comprises:

computer readable code devices for determining, at a first transceiver of the pair of transceivers, channel and noise characteristics for data transmissions in a first direction; and

computer readable code devices for determining, at a second transceiver of the pair of transceivers, channel and noise characteristics for data transmissions in a second direction, and

wherein the first direction performance information is produced based on the channel and noise characteristics for data transmissions in the first direction, and the second direction performance information is produced based on the channel and noise characteristics for data transmissions in the second direction.

8. A computer readable medium as recited in claim 7, wherein the first direction performance information and the second direction performance information are signal-to-noise ratio information.

9. A computer readable medium as recited in claim 7, wherein the first transceiver in within a central office and the second transceiver is a remote unit, and wherein the central office determines the first direction bit allocations and the second direction bit allocations to the exclusion of the remote unit.

10. A computer readable medium as recited in claim 7, wherein the central office receives rate requests from a network coupled to the central office, and none of the rate requests are forwarded to the remote unit.