Integration of remote microcell with CDMA infrastructure

• US 8,014,306 B2
• Filed: 10/28/2005
• Issued: 09/06/2011
• Est. Priority Date: 06/01/1998
• Status: Expired due to Fees

• Current Assignee: SBC Properties, L.P.
• Original Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Inventors: Joyce, Timothy Jason, Fiut, Brian Douglas
• Primary Examiner(s): NGUYEN, STEVEN H D
• Application Number:
  US11/261,251
• Publication Number:
  US 20060062194A1
• Time in Patent Office: 2,139 Days
• Field of Search: 370/252, 370/335, 370/342, 455/562, 455/562.1, 455 6711- 6716, 398 77- 78, 398 25- 33
• US Class Current: 370/252
• CPC Class Codes: H04B 2201/70702 Intercell-related aspects
• CPC Class Codes: H04B 7/2609 Arrangements for range control, e.g. by using remote antennas
• CPC Class Codes: H04B 7/2628 using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA] H04B7/2618 takes precedence
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 4/18 Information format or content conversion, e.g. adaptation by the network of the transmitted or received information for the purpose of wireless delivery to users or terminals

Abstract

A method of interconnecting a CDMA cellsite having signal advancing capabilities with at least one remote microcell without re-synchronization capabilities. The method of the present invention sufficiently advances the signal to compensate for the time delay induced by communication signal travel over a fiber optic connection between a base station cellsite and a remote microcell.

Claims

1. A method of integrating a remote microcell with at least one face of a code division multiple access (CDMA) communication system capable of signal advancing, the method comprising:

dropping all active calls from the remote microcell;

measuring, at an optical time domain reflectometer, a length of a fiber optic connection between a CDMA base station of the CDMA communication system and the remote microcell;

measuring loss in the fiber optic connection;

measuring a power output at the remote microcell;

measuring a power output at the CDMA base station;

collecting data relating to a total number of radios assigned to the remote microcell being integrated with the CDMA communication system, a number of radios assigned to the remote microcell that are in a CDMA bandwidth that have been removed from service, a transmit and receive antenna attenuation setting for the remote microcell, a remote attenuation level, a baseband combiner and radio attenuation of the remote microcell, and a pn-offset of the remote microcell;

installing remote microcell hardware at the CDMA base station;

calculating values using measurement data, the calculated values being a transmit antenna propagation delay, a maximum receive path propagation delay, a maximum transmit differential delay, a sector size, a search window size, power calculation, a total gain, an actual gain, and a CDMA power input level;

translating the calculated values to allow the remote microcell to function in the CDMA communication system and to provide a sufficient sector size;

level setting an output power level of the CDMA base station based on the calculated values to adapt the CDMA base station to communicate with the remote microcell; and

testing the CDMA communication system after restoring the CDMA communication system to normal service.

2. The method of claim 1, further comprising:

checking the CDMA base station; and

determining whether the CDMA base station is in normal operating condition.

3. The method of claim 2 further comprising making necessary changes to bring the CDMA base station into its normal operating condition.

4. The method of claim 1 wherein measuring the length of the fiber optic connection and measuring loss in the fiber optic connection comprises:

disconnecting the fiber optic connection at the remote microcell;

removing the fiber optic connection at the CDMA base station;

connecting the fiber optic connection at the CDMA base station to an optical time domain reflector;

selecting a lower wave-length;

selecting a maximum length dimension;

measuring loss and distance in the fiber optic connection at the lower wave-length using the optical time domain reflector;

selecting an upper wave-length;

measuring loss and distance in the fiber optic connection at the upper wave-length using the optical time domain reflector; and

reconnecting the fiber optic connection at the CDMA base station.

5. The method of claim 1 wherein measuring a power output at the remote microcell further comprises:

calibrating a power meter and a power sensor;

disconnecting an antenna feedline from a radio frequency (RF) output connector of the remote microcell;

connecting the power sensor to the RF output connector of the remote microcell;

identifying a single voice-radio channel unit as a master radio for the remote microcell;

turning on the single voice-radio channel unit;

setting the single voice-radio channel unit to a voice radio attenuation level that is the same as a voice radio attenuation level used by the remote microcell in normal operation;

measuring output power from the power sensor;

reconnecting the antenna feedline to the RF output connector of the remote microcell;

disconnecting the antenna feedline from an RF monitor port of the remote microcell;

connecting the power sensor to the RF monitor port of the remote microcell;

identifying a single voice-radio channel unit as a master radio for the remote microcell;

turning on the single voice-radio channel unit;

setting the single voice-radio channel unit to the voice radio attenuation level that is the same as the voice radio attenuation level used by the remote microcell in normal operation;

measuring the output power from the power sensor; and

reconnecting the antenna feedline to the RF monitor port of the remote microcell.

6. The method of claim 1 wherein measuring the power output at the CDMA base station further comprises, for each digitizer of the CDMA base station:

disconnecting a cable between an output of a radio interference module in the CDMA base station and an input of a first digitizer at the CDMA base station;

connecting a power sensor to the input of the first digitizer;

identifying a single voice-radio channel unit as a master radio;

turning on the single voice-radio channel unit;

setting the voice-radio channel unit to a voice radio attenuation level that is the same as a voice radio attenuation level used by the input of the first digitizer for normal operation;

measuring output power from the power sensor; and

reconnecting the cable.

7. The method of claim 6 wherein the CDMA communication system further comprises simulcast CDMA and further comprising:

ensuring all digitizers have been reconnected; and

measuring a power output at an output port of a CDMA base station transmitter for the remote microcell.

8. The method of claim 1 wherein the CDMA communication system further comprises a stand-alone CDMA base station and installing the remote microcell hardware at the CDMA base station further comprises:

installing a combiner for each face of the stand-alone CDMA base station;

connecting an input cable from a base band assembly to a respective input of the combiner;

measuring an output power level at the combiner;

restoring the base band assembly to service;

adjusting an ouptut gain potentiometer to a predetermined output level;

removing the base band assembly from service;

connecting one end of a transmit cable to the combiner and another end of the transmit cable to an available input on a radio interface module card;

connecting a 10 decibel (dB) attenuator to the combiner;

connecting one end of a receive cable to the 10 dB attenuator and another end of the receive cable to a next available input of the radio interface module card; and

terminating the combiner.

9. The method of claim 1 wherein the CDMA communication system further comprises a simulcast CDMA base station and installing the remote microcell hardware at the CDMA base station further comprises:

removing a first combiner from a transmit cable;

inserting a second combiner on one end of the transmit cable;

connecting another end of the transmit cable to an available input on a radio interface module card;

removing the first combiner from a receive cable;

inserting a second combiner on one end of the receive cable;

attenuating the second combiner on one end of the receive cable;

connecting another end of the receive cable to a next available input on the radio interface module card;

connecting the second combiner with an antenna interface;

re-connecting the first combiner to the receive cable;

restoring a base band assembly to service;

adjusting an output gain potentiometer to a predetermined output level; and

removing the base band assembly from service.

10. The method of claim 1 wherein calculating values further comprises:

calculating the transmit antenna propagation delay for all remote microcells in a stand-alone CDMA base station by multiplying the length of the fiber optic connection by a conversion factor for fiber distance to delay, adding propagation delay induced by the CDMA base station and adding propagation delay induced by a digitizer; and

selecting a lowest value to be used in translating the calculated values.

11. The method of claim 1 wherein the CDMA base station is a simulcast CDMA base station and calculating values further comprises setting the transmit antenna propagation delay to a predefined fixed value.

12. The method of claim 1 wherein calculating values further comprises:

calculating the maximum receive path propagation delay for each remote microcell being integrated with a stand alone CDMA base station by multiplying the length of the fiber optic connection by a conversion factor for fiber length to delay, adding a propagation delay induced by the CDMA base station and a propagation delay induced by a digitizer; and

selecting a lowest value of the maximum receive path propagation delay to be used in translating the calculated values.

13. The method of claim 1 wherein the CDMA base station is a simulcast CDMA base station and calculating values further comprises setting the maximum receive path propagation delay to a predefined fixed value.

14. The method of claim 1 wherein calculating values further comprises:

calculating the maximum transmit differential delay for each remote microcell at a stand alone CDMA base station by averaging the transmit antenna propagation delay with the maximum receive path propagation delay for each remote microcell to result in a total transmit differential delay for each remote microcell; and

selecting a maximum value to be used in translating the calculated values.

15. The method of claim 1 wherein the CDMA base station is a simulcast CDMA base station and calculating values further comprises:

for each remote microcell for the simulcast CDMA base station;

adding the transmit antenna propagation delay and the maximum receive path propagation delay to obtain a sum;

subtracting a base station induced transmit propagation delay and a base station induced receive propagation delay to obtain a difference; and

dividing the difference by two for a total transmit differential delay; and

selecting a maximum value to be used in translating the calculated values.

16. The method of claim 1 wherein calculating values further comprises:

calculating a transmit differential delay for each remote microcell;

selecting the largest transmit differential delay;

selecting the smallest transmit differential delay; and

subtracting the smallest transmit differential delay from the largest transmit differential delay to calculate the maximum transmit differential delay.

17. The method of claim 16 wherein calculating values further comprises adding a predetermined freespace propagation delay to the maximum transmit differential delay to determine a sector size translation value.

18. The method of claim 16 wherein the CDMA base station is a stand-alone CDMA base station and further comprising:

adding to the maximum transmit differential delay a predetermined additional delay based on a distance assumption to the maximum transmit differential delay to obtain a sum; and

multiplying the sum by two to determine a cell search window size.

19. The method of claim 16 wherein the CDMA base station is a simulcast CDMA base station and further comprising:

subtracting a predetermined base station induced delay from the maximum transmit differential delay to obtain a difference;

adding to the difference a predetermined additional delay based on a distance assumption to obtain a sum; and

multiplying the sum by two to determine a cell search window size.

20. The method of claim 1 wherein level setting further comprises:

configuring the CDMA base station for a pilot acting as a beacon for a mobile device to locate a base station;

recording existing values for a paging channel gain and a synchronization channel gain;

updating the values for the paging channel gain and the synchronization channel gain to zero;

adjusting the power output of the CDMA base station to a calculated value; and

restoring the values for the paging channel gain and the synchronization channel gain to the values prior to updating the values to zero.

21. The method of claim 1 wherein testing the CDMA communication system further comprises:

checking for RF leakage in the CDMA base station; and

checking for normal propagation at the remote microcell.

22. A method of adapting CDMA base station to communicate with a remote microcell, the method comprising:

measuring a length of a fiber optic connection between the CDMA base station and the remote microcell using an optical time domain reflector;

determining a transmit differential delay based on the measured length;

measuring a loss in the fiber optic connection using the optical time domain reflector;

measuring power output at the remote microcell using a power sensor to determine a first output power associated with the remote microcell;

measuring a power output at the CDMA base station to determine a second output power associated with the CDMA base station;

calculating a total gain based on the first and second output powers and the loss; and

adjusting power at the CDMA base station based on the first and second output powers to adapt the CDMA base station to communicate with the remote microcell.

23. The method of claim 22, further comprising calculating a sector size associated with the remote microcell based on the transmit differential delay.

24. The method of claim 22, further comprising calculating a cell search window size based on the transmit differential delay.

25. The method of claim 22, further comprising identifying a single voice radio channel of the remote microcell as a master radio of the remote microcell before measuring the power output at the remote microcell.

26. The method of claim 25, wherein the master radio is set to a voice radio attenuation level that the remote microcell uses in normal operation before measuring the power output at the remote microcell.

27. The method of claim 22, wherein the fiber optic connection is disconnected prior to measuring the length.

28. The method of claim 22, wherein the length and the loss are measured at a first wavelength and at a second wavelength, the first wavelength being lower than the second wavelength.

29. The method of claim 22, wherein determining the transmit differential delay comprises:

calculating a transmit propagation delay for each remote microcell connected to the CDMA base station;

selecting a largest calculated transmit propagation delay;

calculating a receive propagation delay for each remote microcell connected to the CDMA base station;

selecting a largest calculated receive propagation delay; and

calculating the transmit differential delay based on the largest calculated transmit propagation delay and the largest receive propagation delay.