Gain control circuit supporting dynamic gain control in a remote unit in a wireless distribution system (WDS)
A gain control circuit in a wireless distribution system (WDS) is provided. The gain control circuit generates a combined digital communications signal based on a number of received radio frequency (RF) communications signals. The combined digital communications signal has a digital amplitude(s) representing a summed analog power level(s) of the RF communications signals in a predefined number of binary bits. When the summed analog power level(s) exceeds a maximum analog power level represented by the digital amplitude(s) in the predefined number of binary bits, the gain control circuit determines a selected RF communications signal(s) causing the summed analog power level to exceed the maximum analog power level and attenuates the selected RF communications signal(s) to reduce the summed analog power level to below the maximum analog power level. As such, it is possible to achieve a calculated balance between performance, complexity, and cost in the gain control circuit.
1. A remote unit in a wireless distribution system (WDS) comprising a gain control circuit, the gain control circuit comprising:
a plurality of radio frequency (RF) circuits configured to receive and amplify a plurality of RF communications signals, respectively;
signal conversion circuitry comprising a plurality of RF signal inputs coupled to the plurality of RF circuits and a digital signal output, the signal conversion circuitry configured to:
receive the plurality of RF communications signals via the plurality of RF signal inputs;
generate a combined digital communications signal based on the plurality of RF communications signals, wherein the combined digital communications signal has a digital amplitude representing a summed analog power level of the plurality of RF communications signals in a predefined number of binary bits; and
provide the combined digital communications signal to the digital signal output; and
a digital signal processing circuit coupled to the digital signal output, the digital signal processing circuit configured to:
determine whether the summed analog power level exceeds a maximum analog power level represented by the digital amplitude in the predefined number of binary bits; and
in response to determining that the summed analog power level exceeds the maximum analog power level:
determine a selected RF circuit among the plurality of RF circuits that generates a selected RF communications signal among the plurality of RF communications signals at a selected analog power level causing the summed analog power level to exceed the maximum analog power level; and
control the selected RF circuit to attenuate the selected RF communications signal.
2. The remote unit of claim 1 , wherein the selected RF circuit is controlled to reduce the summed analog power level to below the maximum analog power level.
3. The remote unit of claim 2 , further comprising multiplexer circuitry configured to:
receive an aggregated uplink RF communications signal comprising the plurality of RF communications signals; and
split the aggregated uplink RF communications signal into the plurality of RF communications signals.
4. The remote unit of claim 3 , wherein the multiplexer circuit is further configured to provide the plurality of RF communications signals to the plurality of RF circuits, respectively.
5. The remote unit of claim 4 , further comprising media interface circuitry coupled to the digital signal processing circuit, the media interface circuitry configured to convert the combined digital communications signal to generate an optical uplink communications signal.
6. The remote unit of claim 3 , further comprising at least one electrical-to-optical converter.
7. The remote unit of claim 6 , further comprising at least one optical-to-electrical converter.
8. The remote unit of claim 1 , further comprising at least one electrical-to-optical converter and at least on optical-to-electrical converter.
9. A wireless distribution system (WDS), comprising:
a plurality of remote units; and
a head-end unit (HEU) coupled to the plurality of remote units via a plurality of communications mediums, respectively, the HEU configured to:
distribute a plurality of downlink communications signals to the plurality of remote units via the plurality of communications mediums, respectively; and
receive a plurality of uplink communications signals from the plurality of remote units via the plurality of communications mediums, respectively;
wherein at least one remote unit among the plurality of remote units comprises a gain control circuit, the gain control circuit comprising:
a plurality of radio frequency (RF) circuits configured to receive and amplify a plurality of RF communications signals, respectively;
signal conversion circuitry comprising a plurality of RF signal inputs and a digital signal output, the signal conversion circuitry configured to:
receive the plurality of RF communications signals via the plurality of RF signal inputs, respectively;
generate a combined digital communications signal based on the plurality of RF communications signals, wherein the combined digital communications signal has a digital amplitude configured to represent a summed analog power level of the plurality of RF communications signals in a predefined number of binary bits; and
provide the combined digital communications signal to the digital signal output; and
a digital signal processing circuit coupled to the digital signal output, the digital signal processing circuit configured to:
analyze the combined digital communications signal to determine whether the summed analog power level exceeds a maximum analog power level that can be represented by the predefined number of binary bits; and
in response to determining that the summed analog power level exceeds the maximum analog power level:
determine a selected RF circuit among the plurality of RF circuits that generates a selected RF communications signal among the plurality of RF communications signals at a selected analog power level causing the summed analog power level to exceed the maximum analog power level; and
control the selected RF circuit to attenuate the selected RF communications signal.
10. The WDS of claim 9 , wherein the selected RF circuit is controlled to reduce the summed analog power level to below the maximum analog power level.
11. The WDS of claim 10 , wherein the HEU is coupled to the plurality of remote units via a plurality of optical fiber communications media, respectively.
12. The WDS of claim 11 , wherein the HEU is further configured to:
receive a plurality of RF downlink communications signals;
convert the plurality of RF downlink communications signals into a plurality of optical downlink communications signals, respectively; and
distribute the plurality of optical downlink communications signals to the plurality of remote units via the plurality of optical fiber communications mediums, respectively.
13. The WDS of claim 12 , wherein the HEU is further configured to:
receive a plurality of optical uplink communications signals from the plurality of remote units via the plurality of optical fiber communications mediums, respectively; and
convert the plurality of optical uplink communications signals into a plurality of RF uplink communications signals, respectively.
14. The WDS of claim 13 , wherein the plurality of remote units is further configured to:
receive the plurality of optical downlink communications signals via the plurality of optical fiber communications mediums, respectively; and
convert the plurality of optical downlink communications signals into the plurality of RF downlink communications signals, respectively.
15. The WDS of claim 14 , wherein the plurality of remote units is further configured to:
receive the plurality of RF uplink communications signals;
convert the plurality of RF uplink communications signals into the plurality of optical uplink communications signals, respectively; and
provide the plurality of optical uplink communications signals to the HEU via the plurality of optical fiber communications mediums, respectively.