Method and apparatus for latency reduction in low power two way communications equipment applications in hybrid fiber coax plants

• US 6,785,564 B1
• Filed: 08/31/2000
• Issued: 08/31/2004
• Est. Priority Date: 08/31/1999
• Status: Expired due to Fees

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Quigley, Thomas J., Rabenko, Ted
• Primary Examiner(s): Corsaro, Nick
• Application Number:
  US09/654,109
• Time in Patent Office: 1,461 Days
• Field of Search: 455/69, 455/564, 455/3.03, 455/574, 370/311, 375/219, 375/222
• US Class Current: 455/574
• CPC Class Codes: H04L 12/12 Arrangements for remote connection or disconnection of substations or of equipment thereof
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04N 21/6118 involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 21/6168 involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 7/17309 Transmission or handling of upstream communications
• CPC Class Codes: H04N 7/22 Adaptations for optical transmission
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A two way communication system is adapted to reduce latency while the communications system is operating in a low power mode. The two way communication system includes a local host having a first primary communication channel and a secondary out of band transmitter; and customer premise equipment having a primary communication channel for communicating with the first primary communication channel of the local host and a secondary low power out of band receiver that receives out of band control signals from the out of band transmitter during low power operation of the customer premise equipment.

Claims

1. A two way communication system comprising:

a local host having a first primary broadband communication channel and a secondary out of band transmitter; and

customer premises equipment having a primary communication channel for communicating with said first primary broadband communication channel of said local host and a secondary low power out of band receiver that receives out of band control signals from said out of band transmitter during low power operation of said customer premises equipment;

wherein said customer premises equipment further comprises one or more peripherals that provide two way communication with one or more communication devices coupled to said customer premises equipment and a processor that monitors activity level of said customer premises equipment and requests a sleep command from said local host when said peripherals have been inactive for a predetermined duration; and

wherein said local host further comprises a host processor that processes said request for sleep command and grants said request in absence of traffic for said customer premises equipment and wherein said host processor activates a downstream filter that buffers communications addressed to said customer premises equipment when said customer premises equipment has been placed in low power mode.

2. The two way communication system of claim 1 wherein said host processor discards best effort communications buffered in said downstream filter.

3. The two way communication system of claim 1 wherein said host processor generates a wake-up message when high priority communications are received by said downstream filter.

4. The two way communication system of claim 3 wherein said out of band transmitter comprises an out of band generator that processes said wake-up message and forwards a wake-up interrupt to said customer premises equipment via an out of band generator PHY.

5. The two way communication system of claim 4 wherein said out of band generator comprises a protocol data unit processor that separates service data unit packets generated by said host processor into one or more transport packets.

6. The two way communication system of claim 5 wherein said out of band generator further comprises a message generator for interfacing said protocol data unit processor with said out of band generator PHY.

7. The two way communication system of claim 4 wherein said out of band generator PHY comprises a symbol mapper for mapping said wake-up interrupt into one or more modulation formats.

8. The two way communication system of claim 7 wherein said out of band generator PHY further comprises a modulator for modulating said mapped wake up interrupt onto quadrature carriers.

9. A two way communication system comprising:

a local host having a first primary broadband communication channel and a secondary out of band transmitter; and

customer premises equipment having a primary communication channel for communicating with said first primary broadband communication channel of said local host and a secondary low power out of band receiver that receives out of band control signals from said out of band transmitter during low power operation of said customer premises equipment;

wherein said secondary low power out of band receiver comprises an out of band receiver PHY and an out of band receiver processor for receiving and processing asynchronous wake-up commands from the local host; and

wherein said out of band receiver PHY comprises a frequency agile local oscillator for down converting channels within a predetermined bandwidth to an intermediate frequency signal.

10. A two way communication system comprising:

a local host having a first primary broadband communication channel and a secondary out of band transmitter; and

customer premises equipment having a primary communication channel for communicating with said first primary broadband communication channel of said local host and a secondary low power out of band receiver that receives out of band control signals from said out of band transmitter during low power operation of said customer premises equipment;

wherein said secondary low power out of band receiver comprises an out of band receiver PHY and an out of band receiver processor for receiving and processing asynchronous wake-up commands from the local host; and

wherein said out of band receiver PHY comprises a digital demodulator for demodulating said asynchronous wake-up commands.

11. The two way communication system of claim 10 wherein said digital demodulator comprises a full quadrature mixer that mixes said asynchronous wake-up commands with a complex data stream generated by a direct digital synthesizer to form in phase and quadrature components.

12. The two way communication system of claim 11 wherein said out of band receiver PHY further comprises a decision feedback equalizer for removing inter-symbol interference in said in phase and quadrature components.

13. The two way communication system of claim 11 wherein said out of band receiver PHY further comprises a forward error correction decoder that decodes said in phase and quadrature components and forwards serial or parallel data to said out of band receiver processor.

14. A method for reducing latency in a communications system comprising:

monitoring activity level of a first transceiver;

disabling a high power channel of said first transceiver as a function of said activity level;

activating a low power channel of said first transceiver to enable reception of control signals from a second transceiver;

the first transceiver generating a request for a sleep command as a function of said activity level of said first transceiver;

the second transceiver verifying a status of said first transceiver; and

the second transceiver communicating an acknowledgement of said request to said first transceiver as a function of said status, wherein said high power channel of said first transceiver is disabled upon receipt of said acknowledgment.

15. The method of claim 14 further comprising the second transceiver activating a downstream traffic filter, the downstream traffic filter facilitating disregarding of low priority traffic to the first transceiver.

16. A method for mitigating latency in a communications system while the communications system is operating at reduced power comprising:

disabling a primary communication channel of a first transceiver;

disabling one or more connected peripheral devices while the primary communication channel is disabled; and

receiving messages from a second transceiver, transmitted on a secondary communication channel, wherein said messages arc used to restore normal operating conditions when an unscheduled, high priority message arrives;

wherein a bandwidth of said secondary channel is less than a bandwidth of said primary communication channel, and wherein the step of communicating with the second transceiver via said secondary communication channel comprises the second transceiver transmitting an address of the first transceiver, and the first transceiver resuming operation of the primary communication channel upon receipt of said address via the secondary communication channel.