Optical fiber-based distributed antenna systems, components, and related methods for calibration thereof
Optical fiber-based wireless systems and related components and methods are disclosed. The systems support radio frequency (RF) communications with clients over optical fiber, including Radio-over-Fiber (RoF) communications. The systems may be provided as part of an indoor distributed antenna system to provide wireless communication services to clients inside a building or other facility. The communications can be distributed between a head end unit (HEU) that receives carrier signals from one or more service or carrier providers and converts the signals to RoF signals for distribution over optical fibers to end points, which may be remote antenna units (RAUs). In one embodiment, calibration of communication downlinks and communication uplinks is performed to compensate for signal strength losses in the system.
1. A method of calibrating a wireless communication system, comprising:
determining a total downlink loss for at least one communication downlink configured to transport electrical radio frequency (RF) signals from at least one base transceiver station (BTS) to a downlink BTS interface and to transport Radio-over-Fiber (RoF) signals converted by at least one optical interface module ( 01 M) from the electrical RF signals to at least one remote antenna unit (RAU);
determining a downlink BTS loss from the total downlink loss;
calibrating a downlink BTS calibration gain in the downlink BTS interface based on the downlink BTS loss;
calibrating at least one RAU calibration gain in the at least one RAU as the total downlink loss minus the downlink BTS loss; and
injecting at least one downlink calibration signal over the at least one communication downlink,
wherein the controller is configured to calibrate the at least one RAU calibration gain in the at least one RAU by setting the at least one RAU calibration gain in at least one attenuator in the at least one RAU.
2. The method of claim 1 , further comprising:
receiving an input signal strength of the at least one downlink calibration signal on the at least one communication downlink; and
determining the total downlink loss by comparing an end signal strength of the at least one downlink calibration signal at the at least one RAU with the input signal strength of the at least one downlink calibration signal.
3. The method of claim 2 , further comprising communicating the at least one downlink calibration signal over at least one communication uplink.
4. A method of calibrating a wireless communication system, comprising:
determining a total downlink loss for at least one communication downlink configured to transport electrical radio frequency (RF) signals from at least one base transceiver station (BTS) to a downlink BTS interface and to transport Radio-over-Fiber (RoF) signals converted by at least one optical interface module (OIM) from the electrical RF signals to at least one remote antenna unit (RAU);
determining a downlink BTS loss from the total downlink loss;
calibrating a downlink BTS calibration gain in the downlink BTS interface based on the downlink BTS loss for a plurality of BTS bands communicated to the at least one BTS; and
automatically calibrating at least one RAU calibration gain in the at least one RAU for the plurality of BTS bands as the total downlink loss minus the downlink BTS loss, wherein the controller is configured to calibrate the at least one RAU calibration gain in the at least one RAU by setting the at least one RAU calibration gain in at least one attenuator.
5. The method of claim 4 , further comprising:
determining a total uplink loss for at least one communication uplink configured to transport RoF signals from the at least one RAU converted to electrical RF signals by the at least one OIM to an uplink BTS interface;
determining an uplink BTS loss from the total uplink loss;
calibrating an uplink BTS calibration gain in the uplink BTS interface based on the uplink BTS loss; and
calibrating at least one OIM calibration gain in the at least one OIM as the total uplink loss minus the uplink BTS loss.
6. The method of claim 5 , wherein the at least one OIM comprises a plurality of OIMs, and further comprising calibrating a separate OIM calibration gain for each of the plurality of OIMs.
7. The method of claim 5 , further comprising injecting at least one uplink calibration signal to be communicated over the at least one communication uplink.
8. The method of claim 5 , further comprising:
receiving an input signal strength of the at least one uplink calibration signal on the at least one communication uplink; and
determining the total uplink loss by comparing an end signal strength of the at least one uplink calibration signal at the uplink BTS interface with the input signal strength of the at least one uplink calibration signal at the at least one RAU.
9. The method of claim 5 , further comprising calibrating the uplink BTS interface and the at least one OIM while electrical RF signals and RoF signals are communicated over the at least one communication uplink.
10. The method of claim 5 , further comprising automatically calibrating the BTS calibration gain in the uplink BTS interface and calibrating the at least one OIM calibration gain in the at least one OIM.
11. A method of calibrating a wireless communication system, comprising:
determining a total downlink loss for at least one communication downlink configured to transport electrical radio frequency (RF) signals from at least one base transceiver station (BTS) to a downlink BTS interface and to transport Radio-over-Fiber (RoF) signals converted by at least one of a plurality of optical interface modules (OIMs) from the electrical RF signals to at least one remote antenna unit (RAU);
determining a downlink BTS loss from the total downlink loss;
automatically calibrating a downlink BTS calibration gain in the downlink BTS interface based on the downlink BTS loss;
calibrating at least one RAU calibration gain in the at least one RAU as the total downlink loss minus the downlink BTS loss; and
determining a total uplink loss for at least one communication uplink configured to transport RoF signals from the at least one RAU converted to electrical RF signals by the at least one OIM to an uplink BTS interface.
12. The method of claim 11 , further comprising:
determining an uplink BTS loss from the total uplink loss;
calibrating an uplink BTS calibration gain in the uplink BTS interface based on the uplink BTS loss; and
calibrating at least one OIM calibration gain in the at least one OIM from the total uplink loss and the uplink BTS loss.
13. The method of claim 12 , further comprising:
injecting at least one uplink calibration signal to be communicated over the at least one communication uplink; and
receiving an input signal strength of the at least one uplink calibration signal on the at least one communication uplink.
14. A method of calibrating a wireless communication system, comprising:
determining a total downlink loss for at least one communication downlink configured to transport electrical radio frequency (RF) signals from at least one base transceiver station (BTS) to a downlink BTS interface and to transport Radio-over-Fiber (RoF) signals converted by at least one optical interface module (OIM) from the electrical RF signals to at least one remote antenna unit (RAU);
determining a downlink BTS loss from the total downlink loss;
calibrating a downlink BTS calibration gain in the downlink BTS interface based on the downlink BTS loss;
calibrating at least one RAU calibration gain in the at least one RAU as the total downlink loss minus the downlink BTS loss;
determining a total uplink loss for at least one communication uplink configured to transport RoF signals from the at least one RAU converted to electrical RF signals by the at least one OIM to an uplink BTS interface;
determining an uplink BTS loss from the total uplink loss; and
calibrating an uplink BTS calibration gain in the uplink BTS interface based on the uplink BTS loss.
15. The method of claim 14 , further comprising calibrating at least one OIM calibration gain in the at least one OIM as the total uplink loss minus the uplink BTS loss.
16. The method of claim 14 , wherein the controller is configured to calibrate the at least one RAU calibration gain in the at least one RAU by setting the at least one RAU calibration gain in at least one attenuator in the at least one RAU.
17. The method of claim 16 , further comprising injecting at least one uplink calibration signal to be communicated over the at least one communication uplink.