INTERLEAVED SIGNALING

• US 20140003477A1
• Filed: 06/29/2012
• Published: 01/02/2014
• Est. Priority Date: 06/29/2012
• Status: Active Grant

• Current Assignee: Cable Television Laboratories Incorporated
• Original Assignee: Cable Television Laboratories Incorporated
• Inventors: Williams, Thomas H.
• Granted Patent: US 8,787,144 B2
• Time in Patent Office: Days
• US Class Current: 375/224
• CPC Class Codes: H04L 25/49 using code conversion at the transmitter; using predistortion; using insertion of idle bits for obtaining a desired frequency spectrum; using three or more amplitude levels ; Baseband coding techniques specific to data transmission systems spectral shaping H04L25/03828

Abstract

Signal interleaving of multiple signals, such as those associated with transmissions within a high-speed data network from subscribers to the Internet or other locations, is contemplated. The transmitted signals may be interleaved by adding signals from one subscriber with those transmitted from another subscriber. The transmitted signals may include spectral holes such that when one or more spectral holes of the signal sent from one subscriber add together with signals from another subscriber, or other simultaneously transmitting device, it fills spectral holes in a manner that maximizes transmission capabilities.

Claims

1. A method of scheduling signal transmission for a plurality of devices configured to transmit signals through different transmission mediums to a combiner for combination into a common transmission medium, the method comprising:

determining attenuation associated with the different transmission mediums used by the plurality of devices to communicate with the combiner;

identifying a first device of the plurality of devices having attenuation within a first attenuation range;

identifying a second device of the plurality of devices having attenuation within a second attenuation range, the second attenuation range being less than the first attenuation range;

instructing the first device to transmit according to pulse amplitude modulation (PAM), including instructing the first device to convert to the frequency domain a first PAM carrier block used to convey the signal transmission, the first PAM being converted to create a first converted PAM carrier block having at least one spectral hole;

instructing the second device to transmit according to orthogonal frequency division multiplexing (OFDM), including instructing the second device to convert a second OFDM carrier block used to convey the signal transmission, the second OFDM carrier block being converted to create a second converted OFDM carrier block that fills at least one of the at least one spectral hole; and

instructing the first device and the second device to respectively transmit the first converted PAM carrier block and the second converted OFDM carrier block at a same frequency band, a same transmission block duration, and a same transmission block start time, thereby resulting in the combiner adding the first converted PAM carrier block with the second converted OFDM carrier block for transmission over the common transmission medium.

2. The method of claim 1 further comprising instructing the first device and the second device to respectively apply a same guard interval duration to the OFDM carrier block and the OFDM carrier block.

3. The method of claim 2 further comprising dynamically determining the same guard interval to be proportional to a greater one of the first and second attenuation ranges.

4. The method of claim 2 further comprising wherein the attenuation determined for the first and second devices includes measurement of associated echoes, and wherein the method further comprises determining the guard interval duration to be greater than a longest echo associated with the attenuation of the first and second devices.

5. The method of claim 1 further comprising:

identifying a third device of the plurality of devices having attenuation within the first attenuation range;

instructing the third device to transmit according to pulse amplitude modulation (PAM), including instructing the third device to convert to the frequency domain a third PAM carrier block used to convey the signal transmission, the third PAM carrier block being converted to create a third converted PAM carrier block that fills at least one of the at least one spectral hole of the first converted PAM carrier block; and

instructing the first device, the second device, and the third device to respectively transmit the first converted PAM carrier block, the second converted OFDM carrier block, and the third converted PAM carrier block at the same frequency band, the same transmission block duration, and the same transmission block start time, thereby resulting in the combiner adding the first converted PAM carrier block, the second converted OFDM carrier block, and the third converted PAM carrier block for transmission over the common transmission medium.

6. The method of claim 1 further comprising:

identifying a third device of the first plurality of devices having attenuation within the first attenuation range;

instructing the third device to transmit according to orthogonal frequency division multiplexing (OFDM), including instructing the third device to convert a third OFDM carrier block used to convey the signal transmission, the third OFDM being converted to create a third converted OFDM carrier block that fills at least one of the at least one spectral hole; and

instructing the first device, the second device, and the third device to respectively transmit the first converted PAM carrier block, the second converted OFDM carrier block, and the third converted OFDM carrier block at the same frequency band, the same transmission block duration, and the same transmission block start time, thereby resulting in the combiner adding the first converted PAM carrier block, the second converted OFDM carrier block, and the third converted OFDM carrier block for transmission over the common transmission medium.

7. The method of claim 1 further comprising identifying the second device to be one of a number of devices having attenuation within the second attenuation range, the second device being the one of the number of devices having attenuation most closely matched to attenuation of the first device.

8. The method of claim 1 further comprising instructing the first device to position at least one of the at least one spectral hole where interferers are located, the interferers corresponding with expected interferences within the transmission mediums such that at least one spectral hole is positioned relative to a frequency band expected to have interferences.

9. A method of scheduling signal transmission for a plurality of devices configured to transmit signals through different transmission mediums to a combiner for combination into a common transmission medium, the method comprising:

determining attenuation associated with the different transmission mediums used by the plurality of devices to communicate with the combiner;

instructing a first portion of the plurality of devices having attenuation within a first attenuation range to transmit at a first instance with a first guard interval such that the corresponding signal transmissions are added together at the combiner for transmission to the common transmission medium; and

instructing a second portion of the plurality of devices having attenuation within a second attenuation range to transmit at a second instance with a second guard interval such that the corresponding signal transmissions are added together at the combiner for transmission to the common transmission medium, the first attenuation being greater than and outside the second attenuation range, the second guard interval being less than the first guard interval.

10. The method of claim 9 further comprising wherein the attenuation determined for the plurality of devices includes measurement of associated echoes, and wherein the method further comprises determining the first guard interval to be greater than a longest echo associated with the attenuation of the first portion of the plurality of devices.

11. The method of claim 9 further comprising performing a ranging operation to determine the attenuation associated with the different transmission mediums used by the plurality of devices.

12. The method of claim 11 further comprising limiting the ranging operation to a third portion of the plurality of devices desiring signal transmission, the third portion including the first and second portions, the third portion desiring signal transmission being identified upon receipt of an electronic message requesting scheduling for signal transmission.

13. The method of claim 9 further comprising selecting the first portion from a third portion of the plurality of devices having attenuation within the first attenuation range, the first portion having a most closely matched attenuation of the third portion of the plurality of devices.

14. The method of claim 9 further comprising:

instructing a first device of the first portion to transmit according to pulse amplitude modulation (PAM), including instructing the first device to convert to the frequency domain a first PAM carrier block used to convey the signal transmission, the first PAM carrier block being converted to create a first converted PAM carrier block having at least one spectral hole;

instructing the second device of the first portion to transmit according to orthogonal frequency division multiplexing (OFDM), including instructing the second device to convert a second OFDM carrier block used to convey the signal transmission, the second OFDM being converted to create a second converted OFDM carrier block that fills at least one of the at least one spectral hole; and

instructing the first device and the second device to respectively transmit the first converted PAM carrier block and the second converted OFDM carrier block at a same frequency band, a same transmission block duration, and a same transmission block start time, thereby resulting in the combiner adding the first converted PAM carrier block with the second converted OFDM carrier block for transmission over the common transmission medium.

15. A method of scheduling signal transmission for a plurality of devices, the method comprising:

determining attenuation associated with different transmission mediums used by the plurality of devices;

identifying a first device of the plurality of devices having attenuation within a first attenuation range;

identifying a second device of the plurality of devices having attenuation within a second attenuation range, the second attenuation range being less than the first attenuation range;

instructing the first device to transmit a first carrier block having at least one spectral hole;

instructing the second device to transmit a second carrier block that fills at least one of the at least one spectral hole; and

instructing the first device and the second device to respectively transmit the first and second carrier blocks at a same guard interval, a same frequency band, a same transmission block duration, and a same transmission block start time.

16. The method of claim 15 further comprising adding the first carrier block with a second carrier block with a combiner located upstream from both of the first and second devices.

17. The method of claim 15 further comprising measuring an echo associated with the different transmission mediums used by the first and second device and selecting the guard interval to be longer than each echo.

18. A method of facilitating removal of linear distortions associated with a signal burst issued from a transmitter to be carried over communication medium to a combiner for further transmission, the method comprising:

determining an echo associated with the communication medium;

adding a pre-distortion to an end of the signal burst, the pre-distortion corresponding with an inverse of the echo; and

transmitting a combined signal over the communication medium, the combined signal including the signal burst and the pre-distortion.

19. The method of claim 18 wherein the burst is a pulse amplitude modulated (PAM) carrier and the method further comprises using frequency domain pre-distortion for the PAM carrier.

20. The method of claim 18 wherein the burst is an orthogonal frequency division multiplexing (OFDM) carrier and the method further comprises using frequency domain pre-distortion for the OFDM carrier.