Transmission system

• US 20050213966A1
• Filed: 04/14/2003
• Published: 09/29/2005
• Est. Priority Date: 04/12/2002
• Status: Active Grant

• Current Assignee: Neptune Subsea IP Ltd. (Xtera Topco Ltd.)
• Original Assignee: Xtera Communications Incorporated (Xtera Topco Ltd.)
• Inventors: Barnes, Stuart, Winterburn, David C., Webb, Stephen M., Chown, Martin
• Granted Patent: US 7,526,205 B2
• Time in Patent Office: Days
• US Class Current: 398/27
• CPC Class Codes: H04J 14/02 Wavelength-division multiplex systems
• CPC Class Codes: H04J 14/0221 Power control, e.g. to keep the total optical power constant
• CPC Class Codes: H04J 14/02216 by gain equalization
• CPC Class Codes: H04L 1/0001 Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• CPC Class Codes: H04L 1/0063 Single parity check
• CPC Class Codes: H04L 25/14 Channel dividing arrangements , i.e. in which a single bit stream is divided between several baseband channels and reassembled at the receiver

Abstract

A wavelength division multiplexing transmission system, the system comprising: a plurality of channels at different wavelengths, each channel comprising a transmitter, a receiver, and one or more amplifiers, the system further comprising an encoder for encoding data with a coding, and; a decoder for decoding transmitted data; prioritising means for prioritising the data on each channel; monitoring means for monitoring directly or indirectly, raw (uncorrected) bit errors on each channel; power adjusting means for, varying the power on a channel in response to tho bit error rate.

Claims

1. A wavelength division multiplexing transmission system, the system comprising:

a plurality of channels at different wavelengths, each channel comprising a transmitter, a receiver, and one or more amplifiers,

the system further comprising an encoder for encoding data with a coding, and;

a decoder for decoding transmitted data;

prioritizing means for prioritizing each channel according to the data carried on that channel;

monitoring means for monitoring directly or indirectly, raw (uncorrected) bit errors on each channel;

power adjusting means for varying the power on a channel in response to the bit error rate of that channel.

2. A transmission system according to claim 1 wherein the data is encoded with FEC coding.

3. A transmission system according to claim 1 wherein the monitoring means comprises a FEC error detection circuit.

4. A transmission system according to claim 1 wherein the monitoring means comprises a multi-level soft decision circuit.

5. A transmission system according to claim 1 further comprising a controller for controlling the power adjusting means.

6. A transmission system according to claim 5 wherein the controller comprises a control algorithm.

7. A transmission system according to claim 1 wherein the means for reducing the power on a channel carrying low priority data is further adapted to additionally switch off a channel.

8. A transmission system according to claim 1 further comprising means for pre-emphasising a channel prior to transmission of data.

9. A method of managing data traffic transmitted via a wavelength division multiplexing transmission system comprising a plurality of channels at different wavelengths, the method comprising the steps of:

allocating a priority to data to be transmitted;

directing data to a predetermined channel in the transmission system according to the priority of the data;

encoding the data prior to transmission using an encoder, and decoding the data after transmission using a decoder;

monitoring directly or indirectly, raw (uncorrected) bit errors on each channel;

adjusting the power to each channel in response to the monitored bit error rate of each channel.

10. A method according to claim 9 wherein the data is encoded with FEC coding.

11. A method according to claim 9 wherein the step of adjusting the power to each channel includes the step of reducing power to channels carrying low priority data, such that, if appropriate, a channel carrying low priority data is switched off.

12. A method according to claim 9, further comprising a first step of calculating the power budget of the system.

13. A method according to claim 9 further comprising a step of re-calculating the used power whenever power to a channel is adjusted.

14. A wavelength division multiplexing transmission system substantially as herein before described with reference to the accompanying drawings.

15. A method of managing data traffic transmitted via wavelength division multiplexing transmission system substantially as herein before described with reference to the accompanying drawings.