System and method for heterodyned communication

Patent metadata

Field	Value
Publication number	US-10090867-B2
Application number	US-201615387543-A
Country	US
Kind code	B2
Filing date	Dec 21, 2016
Priority date	Dec 21, 2015
Publication date	Oct 2, 2018
Grant date	Oct 2, 2018

Abstract

A system and method for protecting a cable modem's receiver from transmitter overload when using a splitter/combiner device in place of a conventional (diplex) filter. Instead of a diplex filter to separate transmit and receive bands, a terminal device can use an isolation device, such as the splitter/combiner, or a circulator. This provides an ability to use a frequency band for either upstream transmissions or downstream reception, but creates a problem of receiver overload when the isolation device has insufficient isolation or a back-reflection occurs. Use of agile local oscillators allows the direction of the signal in the band to change very rapidly. Likewise a receive frequency can by dynamically reassigned by retuning a LO, which may employ direct digital synthesis.

First claim

What is claimed is:

1. A heterodyned communication circuit for a customer premises device (CPE) in a diplexerless wired communication network, comprising:
a tunable receive local oscillator configured to cooperate in up-converting a receive band signal to a bandpass filter frequency for eliminating ingress from a neighboring CPE transmit signal;
a mixer in communication with a splitter/combiner and the receive local oscillator wherein the mixer mixes the receive band signal provided by the splitter/combiner and a signal generated by the receive local oscillator to produce an up-converted heterodyned signal having at least a portion of the neighboring CPE transmit signal and an unwanted image; and
a band pass filter configured with the bandpass frequency and configured to process the heterodyned signal to remove the unwanted image and at least a portion of the upstream signal transmitted by the neighboring CPE from the heterodyned signal.

2. The heterodyned communication circuit of claim 1 , wherein a receive band, which includes the receive band signal, is set apart from a transmit band to reduce any non-linear distortion produced by one of both of a transmitter and a mixer configured with the CPE.

3. The heterodyned communication circuit of claim 1 , wherein a receive band, which includes the receive band signal, is set apart from a transmit band to reduce any non-linear distortion produced by one or both of a transmitter and a mixer configured with a second CPE proximate on the communication network to the CPE.

4. The system of claim 1 , wherein the splitter/combiner is a circulator.

5. The system of claim 1 , wherein the tunable local oscillator is configured to adapt to one or more neighboring CPE different sub-splits frequency plan.

6. The system of claim 5 , wherein the CPE operates with a first sub-split between a first upstream and a first downstream signal and the neighboring CPE operates with a second sub-split between a second upstream and a second downstream signal, wherein a portion of the CPE's first downstream signal partially overlaps a portion of the neighboring CPE's second upstream signal.

7. The system of claim 6 , wherein the CPE's receive heterodyned communication circuit is configured to remove the portion of the neighboring CPE's upstream signal that partially overlaps with the portion of the CPE's downstream signal.

8. The system of claim 1 , wherein the receive local oscillator is a variable frequency local oscillator configured to operate with a changeable sub-split to adapt to a sub-split of one or more neighboring CPEs, and controllable by the CPE which receives data from remotely supplied resource allocations.

9. The system of claim 1 , wherein the wired communication network comprises a full-duplex wired communication network.

10. The system of claim 1 , wherein the wired communication network comprises at least in part a half-duplex wired communication network.

11. The system of claim 1 , wherein the wired communication network comprises a Node plus zero wired communication network.

12. The system of claim 1 , wherein the wired communication network comprises a DOCSIS network.

13. The system of claim 1 , where the receive local oscillator's tunable oscillator frequency is determined by a scheduler remote from the CPE and the neighboring CPE.

14. The system of claim 13 , where the scheduler is configured with a headend device in a DOCSIS network.

Assignees

• Cable Television Laboratories Inc

Inventors

• Williams Thomas

Classifications

• H04B1/0057 Primary

  using diplexing or multiplexing filters for selecting the desired band · CPC title

• H04L5/1461

  Suppression of signals in the return path, i.e. bidirectional control circuits · CPC title

• H04B1/30 Primary

  for homodyne or synchrodyne receivers (demodulator circuits H03D1/22) · CPC title