Systems and methods for transporting digital RF signals
A telecommunications system is provided that can re-sample a digitized signal at a resample rate that is based on one or more factors to better utilize bandwidth. The factors can include the bandwidth of the signal that the digitized signal represents, the amount of bandwidth owned or used by the carrier, the full bandwidth of the designated RF band, the bandwidth of the serial link, the frame length of the serial link, the segmentation of the frames on the serial link, and the capability of the equipment at the receiving end of a serial link. The re-sampled signal can be transmitted to another unit that is remote to the unit transmitting the signal. The other unit can include a re-sampling device that restores the re-sampled signal to a digital signal that can be converted to an analog signal for wireless transmission.
1. A distributed antenna system comprising:
a master unit comprising:
an analog-to-digital converter configured to use a sample rate to convert downlink radio frequency signals to digital downlink signals;
re-sampling devices configured to output re-sampled digital downlink signals by re-sampling the digital downlink signals at customized resample rates that are less than the sample rate and that are based on at least one factor, the re-sampled digital downlink signals having a smaller bandwidth than the digital downlink signals; and
a framer configured to multiplex the re-sampled digital downlink signals and to generate a first frame that includes the re-sampled digital downlink signals as framed data for transport to one or more remote units of the distributed antenna system, wherein the one or more remote units of the distributed antenna system are configured to transmit radio frequency signals using at least one antenna, wherein the transmitted radio frequency signals are derived from the framed data of the first frame received from the master unit.
2. The distributed antenna system of claim 1 , wherein the first frame contains more information as compared to a second frame containing the digital downlink signals and that is a same size as the first frame.
3. The distributed antenna system of claim 1 , wherein the customized resample rates include a first resample rate and a second resample rate that is at a different rate than the first resample rate.
4. The distributed antenna system of claim 1 , further comprising:
a serializer configured to serialize the framed data; and
a transmitter configured to output serialized framed data from the serializer on a communication medium for receipt by the one or more remote units.
5. The distributed antenna system of claim 1 , wherein the first frame is an Ethernet frame comprising a preamble, a start frame delimiter, a destination address, a source address, length or type, MAC client data, packet assembler/dissembler, a frame check sequence, and an extension.
6. The distributed antenna system of claim 1 , further comprising:
the one or more remote units associated with antennas and configured to provide wireless coverage in an area, at least one remote unit of the one or more remote units comprising:
a de-framer configured to extract the re-sampled digital downlink signals;
remote unit re-sampling devices configured to re-sample the digital downlink signals to produce remote unit digital downlink signals at a remote unit resample rate that is higher than the customized resample rates; and
a digital-to-analog converter configured to produce the downlink radio frequency signals from the remote unit digital downlink signals.
7. The distributed antenna system of claim 1 , wherein the at least one factor includes a bandwidth owned by a carrier that is a source of the downlink radio frequency signals.
8. The distributed antenna system of claim 1 , wherein the at least one factor includes the bandwidth of a communication medium between the master unit and the one or more remote units.
9. The distributed antenna system of claim 1 , wherein the at least one factor includes the bandwidth of the downlink radio frequency signals.
10. The distributed antenna system of claim 1 , wherein the analog-to-digital converter and at least one of the re-sampling devices are disposed in an integrated device in the master unit.
11. A distributed antenna system, comprising:
a remote unit configured to be associated with an antenna for providing wireless coverage in an area, the remote unit comprising:
an analog-to-digital converter configured to use a sample rate to convert uplink radio frequency signals to digital uplink signals;
re-sampling devices configured to output re-sampled digital uplink signals by re-sampling the digital uplink signals at customized resample rates that are less than the sample rate and that are based on at least one factor, the re-sampled digital uplink signals having a smaller bandwidth than the digital uplink signals; and
a framer configured to multiplex the re-sampled digital uplink signals and to generate a first frame that includes the re-sampled digital uplink signals as framed data for transport to a master unit of the distributed antenna system, wherein master unit of the distributed antenna system is configured to communicate uplink signals derived from the framed data of the first frame received from the remote unit.
12. The distributed antenna system of claim 11 , wherein the first frame contains more information as compared to a second frame containing the digital uplink signals and that is a same size as the first frame.
13. The distributed antenna system of claim 11 , wherein the customized resample rates include a first resample rate and a second resample rate is at a different rate than the first resample rate.
14. The distributed antenna system of claim 11 , further comprising:
a serializer configured to serialize the framed data; and
a transmitter configured to output serialized framed data from the serializer on a communication medium for receipt by the master unit.
15. The distributed antenna system of claim 11 , wherein the first frame is an Ethernet frame comprising a preamble, a start frame delimiter, a destination address, a source address, length or type, MAC client data, packet assembler/dissembler, a frame check sequence, and an extension.
16. The distributed antenna system of claim 11 , further comprising:
the master unit configured to communicatively couple to one or more base stations, the master unit comprising:
a de-framer configured to extract the re-sampled digital uplink signals;
master unit re-sampling devices configured to re-sample the digital uplink signals to produce master unit digital uplink signals at a master unit resample rate that is higher than the customized resample rates; and
a digital-to-analog converter configured to produce the uplink radio frequency signals from the master unit digital uplink signals.
17. The distributed antenna system of claim 11 , wherein the at least one factor includes the bandwidth of a communication medium between the master unit and the remote unit.
18. The distributed antenna system of claim 11 , wherein the at least one factor includes the bandwidth of the uplink radio frequency signals.
19. The distributed antenna system of claim 11 , wherein the analog-to-digital converter and at least one of the re-sampling devices are disposed in an integrated device in the remote unit.
20. A method, comprising:
digitizing downlink radio frequency signals to digital downlink signals using a sample rate at a master unit of a distributed antenna system;
re-sampling the digital downlink signals at the master unit at customized resample rates that are less than the sample rate and that are based on at least one factor to output re-sampled digital downlink signals, the re-sampled digital downlink signals having a smaller bandwidth than the digital downlink signals;
multiplexing the re-sampled digital downlink signals at the master unit;
generating a frame at the master unit, the frame including the re-sampled digital downlink signals as framed data for transport to one or more remote units to provide wireless coverage in an area;
transporting the frame including the framed data to the one or more remote units from the master unit;
deriving radio frequency signals from the framed data of the first frame at the one or more remote units; and
transmitting the derived radio frequency signals using at least one antenna at the one or more remote units.