Power line communications system and method of operation thereof

• US 6,522,626 B1
• Filed: 03/30/1999
• Issued: 02/18/2003
• Est. Priority Date: 12/15/1998
• Status: Expired due to Term

• Current Assignee: RPX Clearinghouse LLC (RPX Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Greenwood, Christopher John
• Primary Examiner(s): Patel, Ajit
• Application Number:
  US09/281,490
• Time in Patent Office: 1,421 Days
• Field of Search: 370/203,204,208,210,343 340/310.01,310.02,310.03 375/285,346 379/93.01,90.01
• US Class Current: 370/208
• CPC Class Codes: H04B 2203/5408 using protocols
• CPC Class Codes: H04B 2203/5416 by adding signals to the wave form of the power source
• CPC Class Codes: H04B 2203/5425 improving S/N by matching impedance, noise reduction, gain control
• CPC Class Codes: H04B 2203/5445 Local network
• CPC Class Codes: H04B 2203/5466 using three phases conductors
• CPC Class Codes: H04B 2203/5483 using coupling circuits
• CPC Class Codes: H04B 3/542 the information being in digital form
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01

Abstract

An Orthogonal Frequency Division Multiplexed (OFDM) power line communications system comprising a power line for distributing electricity to a plurality of premises and a communication station coupled to the power line at one of the premises, which station uses a part of the power line external to the premises as a communications medium. The communications station includes a receiver which comprises a clipping system adapted to clip an incoming OFDM data waveform, which includes a regular impulsive noise component, so as to reduce the level of noise on the waveform.

Claims

1. An OFDM power line modem receiver comprising a clipping system adapted to clip an incoming OFDM data waveform, which includes a regular impulsive noise component, so as to reduce the level of said noise on the waveform and further comprising a Fourier Transform element and a gain control element, wherein the clipping system and the gain control element act upon a received signal prior to its application to the Fourier Transform element.

2. The receiver of claim 1, adapted to receive a coded OFDM signal (COFDM), wherein the clipping level can be altered, enabling the clipping level to be set such that the COFDM signal is not corrupted beyond the error correcting capabilities of the coding scheme utilised while reducing the power in the noise signal thus preventing corruption of the data in the waveform upon detection.

3. The method of claim 1 adapted to receive a coded ODFM signal (CODFM), wherein the clipping level can be altered, enabling the clipping level to be set such that the COFDM signal is not corrupted beyond the error correcting capabilities of the coding scheme utilised while reducing the power in the noise signal thus preventing corruption of the data in the waveform upon detection.

4. The method of claim 3 adapted to receive a coded OFDM signal (COFDM), wherein the clipping level can be altered, enabling the clipping level to be set such that the COFDM signal is not corrupted beyond the error correcting capabilities of the coding scheme utilised while reducing the power in the noise signal thus preventing corruption of the data in the waveform upon detections.

5. The method of claim 1, wherein the signals comprise data packets which are transmitted with a bit rate of at least 500 kbps.

6. The method of claim 3, wherein the signals are carried over the power line in the frequency band greater than 1 MHz.

7. The method of claim 3, wherein the signals comprise data packets which are transmitted with a bit rate of at least 500 kbps.

8. The communications system of claim 6, which is operable to select a bit rate for transmitting/receiving communications signals over the power line from a plurality of different bit rates.

9. The communications system of claim 8 adapted to receive a coded OFDM signal (COFDM), wherein the clipping level can be altered, enabling the clipping level to be set such that the COFDM signal is not corrupted beyond the error correcting capabilities of the coding scheme utilised while reducing the power in the noise signal thus preventing corruption of the data in the waveform upon detection.

10. The communications system of claim 8, which is operable to select a bit rate for transmitting/receiving communications signals over the power line from a plurality of different bit rates.

11. The communications system of claim 6, further comprising a management unit, which is responsive to management signals received over the power line.