Selectively combining uplink signals in distributed antenna systems
Certain aspects involve selectively combining uplink transmissions in a distributed antenna system (“DAS”). For example, a unit of the DAS can receive baseband uplink transmissions from remote units of the DAS via a first channel and a second channel. The unit can generate a first combined uplink signal by combining baseband uplink transmissions received from a first subset of the remote units via the first channel that include data for transmission to a base station. The unit can generate a second combined uplink signal that includes baseband uplink transmissions received from a second subset of the remote units via the second channel and excludes or attenuates baseband uplink transmissions that are received from the first subset of the remote units via the second channel and that lack data for transmission to the base station are excluded or attenuated. The unit can transmit the combined uplink signals to the base station.
1. A method comprising:
receiving baseband uplink transmissions from remote units of a distributed antenna system via a first channel and a second channel;
generating a first combined uplink signal by combining a first portion of the baseband uplink transmissions received from a first subset of the remote units via the first channel, wherein the first portion of the baseband uplink transmissions is determined to include data for transmission to a base station;
generating a second combined uplink signal by combining a second portion of the baseband uplink transmissions received from a second subset of the remote units via the second channel, wherein generating the second combined uplink signal comprises attenuating or excluding a third portion of the baseband uplink transmissions that are received from the first subset of the remote units via the second channel and that is determined to lack data for transmission to the base station; and
transmitting the first combined uplink signal and the second combined uplink signal to the base station.
2. The method of claim 1 , further comprising:
determining that the first portion of the baseband uplink transmissions includes the data based on the first portion of the baseband uplink transmissions having a signal strength equal to or exceeding a threshold;
determining that the third portion of the baseband uplink transmissions lacks the data based on the third portion of the baseband uplink transmissions having a signal strength less than the threshold.
3. The method of claim 1 , further comprising:
receiving spreading codes from the base station;
determining that the first portion of the baseband uplink transmissions includes the data based on the first portion of the baseband uplink transmissions having at least one of the spreading codes; and
determining that the third portion of the baseband uplink transmissions lacks the data based on the spreading codes being absent from the third portion of the baseband uplink transmissions.
4. The method of claim 1 , further comprising determining that the first portion of the baseband uplink transmissions includes the data based on determining that at least one terminal device is utilizing an RF channel corresponding to the first channel and determining that the at least one terminal device is located within a threshold distance of the first subset of the remote units.
5. The method of claim 1 , further comprising:
receiving information from the base station identifying an RF channel that corresponds to the first channel and that is utilized by at least one terminal device; and
selecting the first portion of the baseband uplink transmissions for inclusion in the first combined uplink signal based on the received information.
6. The method of claim 1 , further comprising determining that no terminal devices are located within a threshold distance of an additional subset of the remote units, wherein an additional portion of the baseband uplink transmissions received from the additional subset of the remote units is excluded from or attenuated in at least one of the first combined uplink signal and the second combined uplink signal.
7. The method of claim 1 , further comprising:
receiving, by the remote units, uplink transmissions via an RF band including a first RF channel corresponding to the first channel and a second RF channel corresponding to the second channel;
extracting the baseband uplink transmissions for the first channel from the received uplink transmissions in the first RF channel and extracting the baseband uplink transmissions for the second channel from the received uplink transmissions in the second RF channel; and
transmitting the baseband uplink transmissions to a unit of the distributed antenna system.
8. The method of claim 1 , wherein the unit is further configured for:
determining that the first portion of the baseband uplink transmissions includes the data based on the first portion of the baseband uplink transmissions having a signal strength equal to or exceeding a threshold;
determining that the third portion of the baseband uplink transmissions lacks the data based on the third portion of the baseband uplink transmissions having a signal strength less than the threshold.
9. The method of claim 1 , wherein the unit is further configured for:
receiving spreading codes from the base station;
determining that the first portion of the baseband uplink transmissions includes the data based on the first portion of the baseband uplink transmissions having at least one of the spreading codes; and
determining that the third portion of the baseband uplink transmissions lacks the data based on the spreading codes being absent from the third portion of the baseband uplink transmissions.
10. The method of claim 1 , wherein the unit is further configured for determining that the first portion of the baseband uplink transmissions includes the data based on determining that at least one terminal device is utilizing an RF channel corresponding to the first channel and determining that the at least one terminal device is located within a threshold distance of the first subset of the remote units.
11. The method of claim 1 , wherein the unit is further configured for:
receiving information from the base station identifying an RF channel that corresponds to the first channel and that is utilized by at least one terminal device; and
selecting the first portion of the baseband uplink transmissions for inclusion in the first combined uplink signal based on the received information.
12. The method of claim 1 , wherein the unit is further configured for determining that no terminal devices are located within a threshold distance of an additional subset of the remote units, wherein an additional portion of the baseband uplink transmissions received from the additional subset of the remote units is excluded from or attenuated in at least one of the first combined uplink signal and the second combined uplink signal.
13. A unit of a distributed antenna system, the unit comprising:
a processing device configured for:
receiving baseband uplink transmissions from remote units of the distributed antenna system via a first channel and a second channel,
determining that a first portion of the baseband uplink transmissions received from a first subset of the remote units via the first channel includes data for transmission to a base station,
determining that a second portion of the baseband uplink transmissions received from a second subset of the remote units via the second channel includes data for transmission to the base station, and
determining that a third portion of the baseband uplink transmissions received from the first subset of the remote units lacks data for transmission to the base station;
a combiner module included in or communicatively coupled to the processing device, the combiner module configured for:
generating a first combined uplink signal by combining the first portion of the baseband uplink transmissions, and
generating a second combined uplink signal by combining the second portion of the baseband uplink transmissions, wherein generating the second combined uplink signal comprises attenuating or excluding the third portion of the baseband uplink transmissions; and
a transmitter configured for transmitting the first combined uplink signal and the second combined uplink signal to the base station.
14. The unit of claim 13 , wherein the processing device is further configured for:
determining that the first portion of the baseband uplink transmissions includes the data based on the first portion of the baseband uplink transmissions having a signal strength equal to or exceeding a threshold;
determining that the third portion of the baseband uplink transmissions lacks the data based on the third portion of the baseband uplink transmissions having a signal strength less than the threshold.
15. The unit of claim 13 , wherein the processing device is further configured for:
receiving spreading codes from the base station;
determining that the first portion of the baseband uplink transmissions includes the data based on the first portion of the baseband uplink transmissions having at least one of the spreading codes; and
determining that the third portion of the baseband uplink transmissions lacks the data based on the spreading codes being absent from the third portion of the baseband uplink transmissions.
16. The unit of claim 13 , wherein the processing device is further configured for determining that the first portion of the baseband uplink transmissions includes the data based on determining that at least one terminal device is utilizing an RF channel corresponding to the first channel and determining that the at least one terminal device is located within a threshold distance of the first subset of the remote units.
17. The unit of claim 13 , wherein the processing device is further configured for:
receiving information from the base station identifying an RF channel that corresponds to the first channel and that is utilized by at least one terminal device; and
selecting the first portion of the baseband uplink transmissions for inclusion in the first combined uplink signal based on the received information.
18. The unit of claim 13 , wherein the processing device is further configured for determining that no terminal devices are located within a threshold distance of an additional subset of the remote units, wherein the combiner module is configured for excluding or attenuating an additional portion of the baseband uplink transmissions received from the additional subset of the remote units in at least one of the first combined uplink signal and the second combined uplink signal.
19. The unit of claim 13 , wherein the combiner module comprises an adder communicatively coupled to the processing device and an attenuator coupled to an input of the adder and configured for attenuating the third portion of the baseband uplink transmissions.
20. A distributed antenna system comprising:
remote units configured for
receiving uplink transmissions via an RF band including a first RF channel corresponding to a first channel and a second RF channel corresponding to a second channel;
extracting baseband uplink transmissions for the first channel from the received uplink transmissions in the first RF channel and extracting baseband uplink transmissions for the second channel from the received uplink transmissions in the second RF channel; and
transmitting the baseband uplink transmissions to a unit; and
the unit communicatively coupled to the remote units and configured for:
generating a first combined uplink signal by combining a first portion of the baseband uplink transmissions received from a first subset of the remote units via the first channel, wherein the first portion of the baseband uplink transmissions is determined to include data for transmission to a base station,
generating a second combined uplink signal by combining a second portion of the baseband uplink transmissions received from a second subset of the remote units via the second channel, wherein generating the second combined uplink signal comprises attenuating or excluding a third portion of the baseband uplink transmissions that are received from the first subset of the remote units via the second channel and that are determined to lack data for transmission to the base station, and
transmitting the first combined uplink signal and the second combined uplink signal to the base station.