SYSTEMS AND METHODS FOR REINFORCING SIGNALS ON COUPLED CHANNELS DURING IDLE PERIODS

Abstract

A method for reinforcing signals on coupled channels during idle periods transmits a first signal on a destination channel and a second signal on a source channel. The second signal is formulated to produce an optimal signal coupled into the destination channel to reinforce the first signal and is sent during idle periods in the source channel.

Claims

1. A method comprising: transmitting a first signal on a destination channel; and transmitting a second signal on a source channel coupled to the destination channel wherein the second signal is formulated to produce an optimal signal coupled into the destination channel to reinforce the first signal.

2. The method of claim 1 wherein transmitting the second signal comprises transmitting the second signal on a source channel that is not in service or during an idle period in the source channel.

3. The method of claim 1 wherein the second signal is a replica of the first signal modified in phase and amplitude as a function of frequency.

4. The method of claim 1 wherein the second signal is based on coupling characteristics between the source channel and destination channel.

5. The method of claim 1 further comprising sending training signals on the source channel to determine coupling characteristics between the source channel and the destination channel.

6. The method of claim 1 further comprising selecting the source channel from among a plurality of source channels based on timing of data bursts in each of the plurality of source channels and wherein the source channel is vectored transmission to cancel crosstalk.

7. The method of claim 1 further comprising adjusting the transmitting of the second signal based on the source channel or the destination channel so as to better align reinforcement of the signal.

8. A system comprising: a processor; a computer-readable medium in communication with the processor wherein the processor is configured to execute an application stored in the computer-readable medium for performing operations comprising: transmitting a first signal on a destination channel; and transmitting a second signal on a source channel coupled to the destination channel wherein the second signal is formulated to produce an optimal signal coupled into the destination channel to reinforce the first signal.

9. The system of claim 8 wherein transmitting the second signal comprises transmitting the second signal on a source channel that is not in service or during an idle period in the source channel.

10. The system of claim 8 wherein the second signal is a replica of the first signal modified in phase and amplitude as a function of frequency.

11. The system of claim 8 wherein the second signal is based on coupling characteristics between the source channel and destination channel.

12. The system of claim 8 wherein the processor is configured to execute an application stored in a computer readable medium for performing operations further comprising sending training signals on the source channel to determine coupling characteristics between the source channel and the destination channel.

13. The system of claim 8 wherein the processor is configured to execute an application stored in a computer readable medium for performing operations further comprising selecting the source channel from among a plurality of source channels based on timing of data bursts in each of the plurality of source channels and wherein the source channel is vectored transmission to cancel crosstalk.

14. The system of claim 8 wherein the processor is configured to execute an application stored in a computer readable medium for performing operations further comprising adjusting the transmitting of the second signal based on the source channel or the destination channel so as to better align reinforcement of the signal.

15. A non-transitory computer readable medium comprising computer executable instructions embodied in a computer readable medium and when executed by a processor of a computer performs steps comprising: transmitting a first signal on a destination channel; and transmitting a second signal on a source channel coupled to the destination channel wherein the second signal is formulated to produce an optimal signal coupled into the destination channel to reinforce the first signal.

16. The non-transitory computer readable medium of claim 15 wherein transmitting the second signal comprises transmitting the second signal on a source channel that is not in service or during an idle period in the source channel.

17. The non-transitory computer readable medium of claim 15 wherein the second signal is a replica of the first signal modified in phase and amplitude as a function of frequency.

18. The non-transitory computer readable medium of claim 15 wherein the second signal is based on coupling characteristics between the source channel and destination channel.

19. The non-transitory computer readable medium of claim 15 comprising computer executable instructions embodied in the computer readable medium and when executed by processor of the computer performs an additional step of sending training signals on the source channel to determine coupling characteristics between the source channel and the destination channel.

20. The non-transitory computer readable medium of claim 15 comprising computer executable instructions embodied in the computer readable medium and when executed by processor of the computer performs an additional step of selecting the source channel from among a plurality of source channels based on timing of data bursts in each of the plurality of source channels and wherein the source channel is vectored transmission to cancel crosstalk.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is an illustration of a signal that is transmitted through the destination channel at the receiver.

[0013] FIG. 2 is an illustration of a signal that is transmitted through the destination channel at the receiver and a signal that is transmitted through the source channel and a transmitter where there is no coupling.

[0014] FIG. 3 is an illustration of the effect of coupling on a signal transmitted through the destination channel at the receiver.

[0015] FIG. 4 is a flowchart of an embodiment of a method for reinforcing signals from coupled channels during idle periods.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0016] Transmission systems often have periods of time where no user data is being sent in a channel. A channel may be a pair of wires in a multi-pair cable, an optical fiber, free-space light, a radio frequency band, or signals transmitted to or from one of several radio antennas. During the idle periods, traditional systems typically transmit an idle pattern, dummy symbols, send no signal, or it enter a low-power mode where little or no signal is sent. During these idle periods a source channel may be used to transmit a signal formulated to produce the optimal signal coupled into the destination channel to reinforce the destination channel's direct signal. The transmitted reinforcing signal may be a replica of the destination channel's direct signal modified in phase, and amplitude as a function of frequency based on coupling characteristics between the respective channels which was previously learned via training signals sent on the source channel(s).

[0017] Transmissions during idle periods of more than one source channel can be employed to boost the total signal received on the destination channel. The reinforcing signals may be transmitted on multiple channels to produce a greater cumulative boost in the destination channel, or the timing of the reinforcing transmissions from the multiple source channel may be coordinated so as to produce a more stable and continuous degree of reinforcement over time. The stability of signal reinforcement can also be improved by choosing which source channels to use based on the amount of traffic on each channel and also by adjusting the timing of transmission on the source and destination channels.

[0018] Illustrated in FIG. 1 are a source channel 101 and a destination channel 103. FIG. 1 illustrates a signal 105 in the destination channel at the receiver end. The source channel at the transmitter end shows that no signal is being transmitted through the source channel.

[0019] Illustrated in FIG. 2 are the destination channel 101 through which the signal 105 is transmitted. The source channel 103 illustrates a reinforcing signal 107 without the coupling effect on the signal at the destination channel 101.

[0020] FIG. 3 illustrates the reinforcement effect 109 that the reinforcing signal 107 through the source channel 105 has on the signal 105.

[0021] Any number of source channels may be used to provide the reinforcing effect. Illustrated in FIG. 4 is a flowchart of a method 400 for reinforcing signals on coupled channels during idle periods. The method 400 may be employed in channels which also are performing vectored transmission to cancel crosstalk.

[0022] In step 401 the method 400 determines the reinforcing signal via training signals sent on the source channel. The reinforcing signal may be a replica of the destination channel's direct signal modified in phase, and amplitude as a function of frequency based on coupling characteristics between the respective channels.

[0023] In step 403 the method 400 transmits through a transmitter a first signal on the destination channel.

[0024] In step 405 the method 400 transmits through the transmitter the reinforcing signal on a source channel coupled to the destination channel.

[0025] In step 407 the method 400 may transmit a second reinforcing signal on a second source channel coupled to the destination channel. The second reinforcing signal may be transmitted on source channels that are not in service, or during idle periods of source channels that are in service. Selection of the second source channel may be made based on the timings of the data bursts on the respective channels, i.e. choose a source channel which is transmitting at the right time. The timing of sending data on the second source channel or the destination channel may be adjusted so as to better align the signal reinforcement. If the source channel has very high signal to noise ratio margin, the source channel transmission may be pre-coded during active transmission to provide some reinforcing boost to the destination channel.

[0026] In step 409 the method 400 may receive at the receiver the combination of the first signal and the reinforcing effect of the reinforcing signal and the second reinforcing signal.

[0027] Although two source channels are described in the method above, it is contemplated that any number of channels may provide a reinforcing effect as described above.

[0028] When used in combination with forward error control (FEC) error correction such as Reed Solomon coding (block-based error correcting codes) any symbol periods where reinforcing signals are not transmitted can be marked as being more likely to have error for FEC erasure decoding. In FEC, information bits are protected against errors by the transmitting of extra redundant bits, so that if errors occur during transmission the redundant bits can be used by the decoder to determine where the errors have occurred. An erasure code is a forward error correction (FEC) code for the binary erasure channel, which transforms a message of k symbols into a longer message (code word) with n symbols such that the original message can be recovered from a subset of the n symbols.

[0029] The methods described in the examples may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in any form of memory or storage medium such as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM. The memory or storage medium may be coupled to the processor such that the processor can read information from, and write information to, the memory or storage medium. Alternatively, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. In some aspects, the steps and/or actions of a method may reside as one or any combination or set of codes and/or instructions on a machine readable medium and/or computer readable medium, which may be incorporated into a computer program product.

[0030] In any of the exemplary embodiments, the described functions may be implemented in hardware, software, firmware, or any combination thereof. Functions implemented in software may be stored on or transmitted over as instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0031] The previous description of the disclosed examples is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these examples will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other examples without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the examples shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.