Cable modem apparatus and method

• US 6,650,624 B1
• Filed: 05/19/2000
• Issued: 11/18/2003
• Est. Priority Date: 10/30/1998
• Status: Expired due to Term

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Samueli, Henry, Denney, Lisa V., Chen, Feng, Min, Jonathan S., Jones, Christopher R., Nazareth, Sean F., Lu, Fang, Quigley, Thomas J.
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): Boakye, Alexander O.
• Application Number:
  US09/574,558
• Time in Patent Office: 1,278 Days
• Field of Search: 370/352, 370/252, 370/420, 370/421, 370/486, 370/487, 370/489, 370/490, 370/493, 370/498, 375/222, 725/111, 725/112, 725/113, 725/109, 725/110
• US Class Current: 370/252
• CPC Class Codes: H04B 1/1036 with automatic suppression of narrow band noise or interference, e.g. by using tuneable notch filters H04B1/123 takes precedence; filter circuits H03H
• CPC Class Codes: H04J 3/0664 unidirectional timestamps
• CPC Class Codes: H04J 3/0682 by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging
• CPC Class Codes: H04J 3/1694 Allocation of channels in TDM/TDMA networks, e.g. distributed multiplexers Passive Optical Networks H04Q11/0062
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0061 Error detection codes
• CPC Class Codes: H04L 1/203 Details of error rate determination, e.g. BER, FER or WER
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 2025/03808 Transmission of equaliser coefficients
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04L 49/9094 Arrangements for simultaneous transmit and receive, e.g. simultaneous reading/writing from/to the storage element
• CPC Class Codes: H04L 7/0004 Initialisation of the receiver H04L7/0075 and H04L7/10 take precedence
• CPC Class Codes: H04L 7/0029 interpolation of received data signal
• CPC Class Codes: H04L 7/033 using the transitions of the received signal to control the phase of the synchronising-signal-generating means, e.g. using a phase-locked loop
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A number of features for enhancing the performance of a cable transmission system in which data is transmitted between a cable modem termination system at a headend and a plurality of cable modems located different distances from the headend. The power transmission level, slot timing, and equalization of the cable modems are set by a ranging process. Data is transmitted by the modems in fragmented form. Various measures are taken to make transmission from the cable modems robust. The upstream data transmission is controlled to permit multiple access from the cable modems.

Claims

1. A cable modem termination system, comprising:

a burst receiver that receives a signal transmitted via an upstream channel of a cable modem system and generates statistics relating to traffic on said upstream channel, said burst receiver including a demodulator that converts said received signal to binary data;

a media access control that includes a counter that accumulates said statistics; and

a signal path that couples said burst receiver to said media access control and carries said binary data and said statistics from said burst receiver to said media access control;

wherein said binary data and said statistics are encapsulated within a data block, said statistics are encapsulated within a header of said data block to distinguish said statistics from said binary data, and wherein said statistics are included within a status byte of said data block header of said data block.

2. The cable modem termination system of claim 1, wherein said signal path comprises a serial data line.

3. The cable modem termination system of claim 1, wherein said statistics arc related to at least one of:

forward error correction, unique word detection, packet collision, packet energy, or packet length.

15. The cable modem termination system of claim 1, wherein said media access control transmits a command to redefine the frequency spectrum of said upstream channel when said estimated quality of said upstream channel is below a predetermined threshold value.

4. A cable modem termination system, comprising:

a burst receiver that receives a signal transmitted via an upstream channel of a cable modem system and generates statistics relating to traffic on said upstream channel, said burst receiver including a demodulator that converts said received signal to binary data;

a media access control that includes a counter that accumulates said statistics; and

a signal path that couples said burst receiver to said media access control and carries said binary data and said statistics from said burst receiver to said media access control;

wherein said binary data and said statistics are transmitted from said burst receiver to said media access control as a series of bursts.

5. The cable modem termination system of claim 4, wherein said statistics are related to at least one of:

forward error correction, unique word detection, packet collision, packet energy, or packet length.

6. The cable modem termination system of claim 4, wherein said signal path comprises a serial data line.

7. A cable modem termination system, comprising:

a burst receiver that receives a signal transmitted via an upstream channel of a cable modem system and generates statistics relating to traffic on said upstream channel, said burst receiver including a demodulator that converts said received signal to binary data;

a media access control that includes a counter that accumulates said statistics; and

a signal path that couples said burst receiver to said media access control and carries said binary data and said statistics from said burst receiver to said media access control;

wherein said media access control utilizes said accumulated values from said counter to determine additional statistics.

8. The cable modem termination system of claim 7, wherein said additional statistics include at least one of:

number of slots, number of slots with power but no data, number of slots with bad data, number of good data slots, total number of forward error correction blocks, number of forward error correction blocks with correctable errors, number of uncorrectable forward error correction blocks, number of requests received, number of collided requests, number of corrupted requests, number of packets received, number of collided packets, number of corrupted packets, number of ranging messages received, number of collided ranging messages received, or number of corrupted ranging messages.

9. The cable modem termination system of claim 7, wherein said signal path comprises a serial data line.

10. The cable modem termination system of claim 7, wherein said statistics are related to at least one of:

forward error correction, unique word detection, packet collision, packet energy, or packet length.

11. A cable modem termination system, comprising:

a burst receiver that receives a signal transmitted via an upstream channel of a cable modem system and generates statistics relating to traffic on said upstream channel, said burst receiver including a demodulator that converts said received signal to binary data;

a media access control that includes a counter that accumulates said statistics; and

a signal path that couples said burst receiver to said media access control and carries said binary data and said statistics from said burst receiver to said media access control;

wherein said accumulated values from said counter are utilized to estimate the quality of said upstream channel.

12. The cable modem termination system of claim 11, wherein said media access control transmits a command to adjust forward error correction gain in data transmissions on said upstream channel when said estimated quality of said upstream channel is below a predetermined threshold value.

13. The cable modem termination system of claim 11, wherein said media access control transmits a command to change guard band widths in data transmissions on said upstream channel when said estimated quality of said upstream channel is below a predetermined threshold value.

14. The cable modem termination system of claim 11, wherein said media access control transmits a command to reallocate data transmissions on said upstream channel to a new upstream channel when said estimated quality of said upstream channel is below a predetermined threshold value.

16. The cable modem termination system of claim 11, wherein said signal path comprises a serial data line.

17. The cable modem termination system of claim 11, wherein said statistics are related to at least one of:

forward error correction, unique word detection, packet collision, packet energy, or packet length.