Cable modem system with sample and packet synchronization

• US 6,834,057 B1
• Filed: 02/10/2000
• Issued: 12/21/2004
• Est. Priority Date: 02/12/1999
• Status: Expired due to Term

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Horton, John D. Jr., Rabenko, Theodore F., Thi, James C. H.
• Primary Examiner(s): Patel, Ajit
• Assistant Examiner(s): SHAH, CHIRAG G
• Application Number:
  US09/501,850
• Time in Patent Office: 1,776 Days
• Field of Search: 370/468, 370/465, 370/229, 370/230, 370/235, 370/236, 370/503, 375/222
• US Class Current: 370/468
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways

Abstract

A method of processing sampled voice packets from a voice packet sender for transmission over a bit-rate sampled data transmission system, such as by a cable modem over a cable modem termination system, to a voice packet recipient. Unsolicited grant arrivals in response to a request from the voice packet sender coupled to the cable modem are determined. The storing of sampled voice packets is synchronized with the unsolicited grant arrivals. Upon receipt of an unsolicited grant arrival, currently stored sampled voice packets are transmitted to the cable modem for further transmission to the voice packet recipient over the cable modem termination system. The synchronization includes determining time needed between adjacent unsolicited grant arrivals for storing the sampled voice packets and for processing stored sampled voice packets, sampling voice packets by clocking voice packet sampling using a clock derived from a cable modem clock, and scheduling processing of the stored sample voice packets to be ready for transmission at a next unsolicited grant arrival. The time needed determination involves counting time between unsolicited grant arrivals and upon reaching a count indicative of the interval between unsolicited grant arrivals, providing for transmission of the currently stored sampled voice packets at the next unsolicited grant arrival.

Claims

1. A method of processing sampled packets from a packet sender for transmission over a transmission system having a periodically allocated bandwidth to a packet recipient, the method comprising the steps of:

determining unsolicited grant arrivals in response to a request from the packet sender;

determining time needed between adjacent unsolicited grant arrivals for storing the sampled packets and for processing stored sampled packets;

sampling voice packets by clocking packet sampling using a clock derived from and synchronized with a cable modem clock of a cable modem communicative with a cable modem termination system;

scheduling processing of the stored sample packets to be ready for transmission at a next unsolicited grant arrival; and

transmitting, upon receipt of an unsolicited grant arrival, processed sampled packets for further transmission to the packet recipient over the transmission system having a periodically allocated bandwidth;

wherein the step of determining time needed includes the step of counting time between unsolicited grant arrivals and upon reaching a count indicative of the interval between unsolicited grant arrivals, providing for transmission of the currently stored sampled packets at the next unsolicited grant arrival.

2. A method of processing sampled voice packets from a voice packet sender for transmission by a cable modem over a cable modem termination system to a voice packet recipient, the method comprising the steps of:

determining unsolicited grant arrivals in response to a request from the voice packet sender coupled to the cable modem;

synchronizing the storing of sampled voice packets with the unsolicited grant arrivals, by;

determining time needed between adjacent unsolicited grant arrivals for storing the sampled voice packets and for

processing stored sampled voice packets by counting time between unsolicited grant arrivals and upon reaching a count indicative of the interval between unsolicited grant arrivals, providing for transmission of the currently stored sampled voice packets at the next unsolicited grant arrival;

sampling voice packets by clocking voice packet sampling using a clock derived from and synchronized with a cable modem clock; and

scheduling processing of the stored sample voice packets to be ready for transmission at a next unsolicited grant arrival; and

transmitting, upon receipt of an unsolicited grant arrival, currently stored sampled voice packets to the cable modem for further transmission to the voice packet recipient over the cable modem termination system.

3. A method of processing sampled voice packets from a plurality of voice packet senders, each voice packet sender having a channel identifier, for transmission by a cable modem over a cable modem termination system to a Public Switched Telephone Network (PSTN) gateway, the method comprising the steps of:

determining unsolicited grant arrivals in response to a request from the voice packet sender coupled to the cable modem;

synchronizing the storing of sampled voice packets with the unsolicited grant arrivals, by;

determining time needed between adjacent unsolicited grant arrivals for storing the sampled voice packets and for

processing stored sampled voice packets by counting time between unsolicited grant arrivals and upon reaching a count indicative of the interval between unsolicited grant arrivals, and by providing for transmission of the currently stored sampled voice packets at the next unsolicited grant arrival;

sampling voice packets by clocking voice packet sampling using a clock derived from and synchronized with a cable modem clock; and

scheduling processing of the stored sample voice packets to be ready for transmission at a next unsolicited grant arrival; and

transmitting, upon receipt of an unsolicited grant arrival, currently stored sampled voice packets to the cable modem for further-transmission to the PSTN gateway over the cable modem termination system, by synchronizing a clock of the cable modem termination system with a clock of the PSTN and multiplexing transmission based upon the channel identifier such that upon receipt of an unsolicited grant arrival associated with the channel identifier, currently stored sampled voice packets of the voice packet sender identified by the channel identifier are transmitted to the cable modem for further transmission over the cable modem termination system to the voice packet recipient.

4. A system for processing sampled packets from a packet sender for transmission over a transmission system having a periodically allocated bandwidth to a packet recipient, the system comprising:

fixed interval grant arrivals determining means responsive to a request from the packet sender;

means for synchronizing the storing of sampled packets with fixed interval grant arrivals; and

means for transmitting, upon receipt of a fixed interval grant arrival, currently stored sampled packets for further transmission to the packet recipient over the transmission system having a periodically allocated bandwidth;

the fixed interval grant arrivals determining means being responsive to a request from a voice packet sender coupled to a cable modem;

the means for synchronizing storing sampled voice packets with fixed interval grant arrivals and including;

means for determining time needed between adjacent fixed interval grant arrivals for storing the sampled voice packets and for processing stored sampled voice packets by counting time between fixed interval grant arrivals and, upon reaching a count indicative of the interval between fixed interval grant arrivals, providing for transmission of the currently stored sampled voice packets at the next fixed interval grant arrival;

means for sampling voice packets by clocking voice packet sampling using a clock derived from and synchronized with a cable modem clock; and

means for scheduling processing of the stored sample voice packets to be ready for transmission at a next fixed interval grant arrival; and

means for transmitting, upon receipt of a fixed interval grant arrival, currently stored sampled voice packets to the cable modem for further transmission to a voice packet recipient over a cable modem termination system.

5. The system of claim 4, wherein the packet recipient is a Public Switched Telephone Network (PSTN) gateway having a clock synchronized with a clock of the cable modem termination system coupled to the cable modem.

6. The system of claim 4, wherein the means for sampling voice packets includes analog to digital conversion means.

7. The system of claim 4, wherein the means for scheduling processing includes means for processing the sampled packets for voice compression.