ISOLATION MEASUREMENT AND SELF OSCILLATION PREVENTION IN TDD-OFDM REPEATER FOR WIRELESS BROADBAND DISTRIBUTION TO SHADOWED AREAS

• US 20120188919A1
• Filed: 04/05/2012
• Published: 07/26/2012
• Est. Priority Date: 05/16/2008
• Status: Active Grant

• Current Assignee: Aviat U.S., Inc. (Aviat Networks Incorporated)
• Original Assignee: Redline Communications Inc. (Aviat Networks Incorporated)
• Inventors: Subasic, Bojan, Franovici, Florin
• Granted Patent: US 8,953,503 B2
• Time in Patent Office: Days
• US Class Current: 370/279
• CPC Class Codes: H04B 7/15514 for shadowing compensation for satellite mobile telephony service systems H04B7/18536
• CPC Class Codes: H04B 7/15578 by gain adjustment

Abstract

A method for determining isolation status of the RF repeater is provided. A modem in the repeater registers with a base transceiver station (BTS). Uplink output levels of a donor RF transceiver are calibrated and stored in the modem. The modem is synchronized to a BTS transmission received at the donor RF transceiver and the synchronization information is provided to a server RF transceiver of the repeater. Isolation detection and measurement can then be performed between donor transmit antenna and receive server antenna of the RF repeater and the automatic gain control parameter of donor RF transceiver and server RF transceiver are adjusted based upon the isolation detection and measurement value. The isolation and detection can be implemented in a co-processor coupled to the donor and server transceivers.

Claims

1. A method of establishing and maintaining isolation status of a radio frequency (RF) repeater that includes a donor RF transceiver, a server RF transceiver, a donor transmit antenna, a server receive antenna and a modem device, in a time-division-duplexed (TDD) system, the method comprising the steps of:

registering the RF repeater with a base transceiver station (BTS) using said modem device;

adjusting the donor RF output level using a calibrated value for the donor RF transceiver;

synchronizing the modem device to a BTS transmission received at the donor RF transceiver;

providing synchronization information to the server RF transceiver of the repeater via said modem device;

performing isolation detection and measurement between the donor transmit antenna and the server receive antenna of the RF repeater via said modem device to determine an isolation value; and

adjusting automatic gain control parameters of the donor RF transceiver and the server RF transceiver based upon the isolation value via said modem device.

2. The method of claim 1 where in the step of performing isolation detection and measurement further comprises:

detecting a received signal preamble from the modem at the server antenna receiver of the RF repeater;

evaluating, at the modem coupled to the donor transmit antenna, a preamble output level;

evaluating, at the modem coupled to the server receive antenna, a preamble power input level; and

calculating an isolation value between the donor transmit antenna and the server receive antenna using the evaluated preamble output level and preamble power input level.

3. The method of claim 2 wherein the received signal is an OFDM/OFDMA signal.

4. The method of claim 2 wherein the step of performing isolation detection and measurement is performed by a co-processor coupled to the modem device and the donor and server transceivers.

5. The method of claim 4 wherein the preamble is generated by the modem device and output to the donor RFtransceiver.

6. The method of claim 1 wherein the step of performing isolation detection and measurement further comprises performing preamble detection based upon a preamble generated by the modem device, wherein the preamble is detected at the server RF transceiver.

7. The method of claim 1 wherein the step of performing isolation detection and measurement further comprises determining RF output power levels from the donor transmit antenna and RSSI levels received by the server receive antenna and calculating an amount of isolation between the antennas.

8. The method of claim 2 further comprising the step of comparing said isolation value with stored isolation values to determine the adjustments to be made to said automatic gain control parameters.

9. The method of claim 2 wherein the modem device is an IEEE 802.16 compliant modem.

11. The processor of claim 9 wherein the step of performing isolation detection and measurement further comprises:

detecting a received signal preamble from the BTS at the server RF transceiver of the RF repeater;

evaluating a preamble output level from the donor transmit antenna;

evaluating a preamble power input level from the server receive antenna; and

calculating an isolation value between the donor transmit antenna and the server receive antenna using the evaluated preamble output level and preamble power input level.

12. The processor of claim 11 wherein the received signal is an OFDM/OFDMA signal.

13. The method of claim 12 wherein the preamble is generated by the processor and output to the donor transmit transceiver.

14. The processor of claim 12 wherein the step of performing isolation detection and measurement further comprises determining RF output power levels from the donor transmit antenna and RSSI levels received by the server receive antenna and calculating an amount of isolation between the antennas.

15. The processor of claim 12 further comprising the step of comparing calculated isolation value with a stored isolation value to determine the adjustments to be made to said automatic gain control parameters.

16. The processor of claim 12 wherein the preamble is defined by IEEE 802.16.

10. A processor, in a radio frequency (RF) repeater, for establishing and maintaining isolation status of the RF repeater that includes a donor RF transceiver, a server RF transceiver, a donor transmit antenna, a server receive antenna and a modem device, in a time-division-duplexed (TDD) system, the method performing the steps of:

registering the RF repeater with a base transceiver station (BTS);

adjusting the donor RF output level using a calibrated value for the donor RF transceiver

synchronizing the modem device to a BTS transmission received at the donor RF transceiver;

providing synchronization information to the server RF transceiver of the repeater via said modem device;

performing isolation detection and measurement between the donor transmit antenna and the server receive antenna of the RF repeater via said modem device to determine an isolation value; and

adjusting automatic gain control parameters of the donor RF transceiver and the server RF transceiver based upon said isolation value via said modem device.

17. An radio frequency (RF) repeater comprising:

a donor RF transceiver coupled to a donor antenna having a transmit portion and a receive portion;

a server RF transceiver coupled to a server antenna having a transmit portion and a receive portion;

a modem, coupled to the donor transceiver and the server transceiver, the modem performing the steps comprising;

registering the RF repeater with a base transceiver station (BTS);

adjusting the donor RF output level using a calibrated value for the donor RF transceiver ;

synchronizing said modem to a BTS transmission received at the donor RF transceiver;

providing synchronization information to the server RF transceiver of the repeater via said modem;

performing isolation detection and measurement between the transmit portion of the donor antenna and the receive portion of the server antenna of the RF repeater via said modem to determine an isolation value; and

adjusting automatic gain control parameters of the donor RF transceiver and the server RF transceiver based upon said isolation value via said modem.

18. The repeater of claim 17 wherein the modem further performs the steps of:

detecting a received signal preamble from the BTS at said server transceiver;

evaluating a preamble output level from the transmit portion of the donor antenna;

evaluating a preamble power input level from the receive portion of the server antenna;

calculating an isolation value between the transmit portion of the donor antenna and the receive portion of the server antenna using the evaluated preamble output level and preamble power input level; and

adjusting automatic gain control parameters of the donor RF transceiver and the server RF transceiver based upon the isolation value.

19. The repeater of claim 18 wherein the received signal is an OFDM/OFDMA signal.

20. The repeater of claim 19 further comprising a co-processor coupled to the modem and the donor and server transceivers, the co-processor performing the step of isolation detection and measurement in communication with the modem.