COMMUNICATION SYSTEM WITH CHANNEL COMPENSATING EQUALIZER

• US 20130336370A1
• Filed: 06/19/2012
• Published: 12/19/2013
• Est. Priority Date: 06/19/2012
• Status: Active Grant

• Current Assignee: CommScope Technologies, LLC (CommScope Holding Company, Inc.)
• Original Assignee: Andrew LLC (CommScope Holding Company, Inc.)
• Inventors: Jovanovic, Milun, Dussmann, Alfons, Kummetz, Thomas
• Granted Patent: US 8,787,429 B2
• Time in Patent Office: Days
• US Class Current: 375/214
• CPC Class Codes: H04B 1/10 Means associated with receiver for limiting or suppressing noise or interference
• CPC Class Codes: H04B 7/15507 Relay station based processing for cell extension or control of coverage area, network planning with network coordinated processing with regard to cell extension H04W16/26; network topologies using dedicated repeater stations H04W84/047; terminal devices adapted for relaying to or from an other terminal H04W88/04
• CPC Class Codes: H04B 7/15528 Control of operation parameters of a relay station to exploit the physical medium
• CPC Class Codes: H04L 2025/03414 Multicarrier
• CPC Class Codes: H04L 2025/03783 Details of reference signals
• CPC Class Codes: H04L 25/03019 adaptive, i.e. capable of adjustment during data reception
• CPC Class Codes: H04L 27/2662 Symbol synchronisation

Abstract

A communication system and method for extending coverage of a base transceiver station. The communication system includes processing circuitry that receives a communication signal over a wireless channel. The received communication signal is processed through an adaptable equalizer to reduce noise, distortion, interference, and frequency errors. In another aspect of the invention, a frequency of a reference signal in the communication system is adjusted to compensate for frequency errors between the communication system and the source of the communication signal. The equalized and frequency adjusted communication signal is then retransmitted into an extended coverage area. Wireless coverage is thereby provided between a base transceiver station and a mobile device in the extended coverage area.

Claims

1. A communication system comprising:

a donor antenna;

a coverage antenna; and

processing circuitry including an equalizer and that is operatively coupled to the donor and coverage antennas, the processing circuitry receiving a wireless signal through one of the donor or coverage antennas and processing the wireless signal through the equalizer to generate a processed signal for retransmission through the other of the donor or coverage antennas.

2. The communication system of claim 1 wherein the processing circuitry is configured to adapt the equalizer to at least one characteristic of a communication channel that couples the processing circuitry to a source of the wireless signal.

3. The communications system of claim 2, wherein the equalizer includes a plurality of coefficients and is configured to adapt to the communication channel by comparing the processed signal to a known signal and adjusting the equalizer coefficients to reduce the difference between the processed signal and the known signal.

4. The communication system of claim 2 wherein the at least one characteristic includes at least one of a phase transfer function, an amplitude transfer function, or a frequency error.

5. The communication system of claim 4, wherein the at least one characteristic of the communication channel varies with time.

6. The communication system of claim 1 wherein the processing circuitry is further configured to compensate for a frequency error in the wireless signal.

7. The communication system of claim 6 wherein the processing circuitry further includes a reference clock having a frequency and compensates for the frequency error in the received signal by adjusting the frequency of the reference clock.

8. The communication system of claim 7 wherein adjusting the frequency of the reference clock changes the frequency of a local carrier signal.

9. The communication system of claim 6 wherein the processing circuitry compensates for the frequency error in the received signal by adding a frequency offset to the received signal.

10. The communication system of claim 9 wherein the processing circuitry includes a local carrier signal generator that is synchronized to a reference clock, and the frequency offset is added to the receive signal by adding an estimated frequency offset to the reference clock.

11. The communication system of claim 1 wherein the donor antenna receives the wireless signal from a base transceiver station (BTS) over a wireless communication channel and the coverage antenna transmits the processed signal into an extended coverage area.

12. The communications system of claim 1 wherein processing circuitry includes a plurality of equalizers each configured to adapt to at least one characteristic of an associated communication channel.

13. The communications system of claim 1 wherein the communications system includes a repeater.

14. The communications system of claim 1 wherein the communications system includes a distributed antenna system.

15. A method of providing a wireless signal to an extended coverage area, the method comprising:

receiving a signal transmitted through a wireless communication channel;

repairing the signal with an equalizer configured to compensate for distortion added to the signal by the wireless communication channel; and

transmitting the repaired signal into the extended coverage area.

16. The method of claim 15, wherein repairing the signal comprises:

determining a transfer function of the wireless communication channel;

determining coefficients for the equalizer based at least in part on the determined transfer function of the wireless communication channel; and

processing the received signal through the equalizer to compensate for the transfer function of the wireless communication channel.

17. The method of claim 16, wherein determining the transfer function of the wireless communication channel includes determining a phase transfer function of the wireless communication channel.

18. The method of claim 17 wherein determining the phase transfer function of the wireless communication channel includes:

determining a frequency error in the received signal; and

correcting the frequency error by adjusting the frequency of a reference signal.

19. The method of claim 18 wherein the reference signal is generated by a system reference clock.

20. The method of claim 16, wherein determining the transfer function of the wireless communication channel includes determining an amplitude transfer function of the wireless communication channel.