A remote radio unit (RRU) for use with a baseband unit (BBU) in a distributed radio access network (RAN), the RRU comprising:
- conversion circuitry comprising a radio frequency analog interface and digital baseband interface;
- transformation circuitry comprising a baseband interface coupled to the digital baseband interface of the conversion circuitry, and a fronthaul interface;
- interface circuitry coupled to a fronthaul link and to the fronthaul interface of the transformation circuitry, and adapted to communicate over the fronthaul link using an adaptive fronthaul protocol;
- and
- control circuitry coupled to the interface circuitry, the transformation circuitry, and the conversion circuitry;
- the conversion circuitry further comprising receiver circuitry to receive a radio frequency signal from a wireless terminal through the radio frequency analog interface and convert the received radio frequency signal to digital baseband samples sent through the digital baseband interface to the transformation circuitry;
- the transformation circuitry comprising adaptive compression circuitry to adaptively compress the digital baseband samples into fronthaul uplink information under control of the control circuitry, and send the fronthaul uplink information to the interface circuitry though the fronthaul interface;
- the interface circuitry comprising fronthaul link drivers to send the fronthaul uplink information over the fronthaul link to the BBU;
- and
- the control circuitry configured to receive information from the BBU over the fronthaul link through the interface circuitry and control the adaptive compression circuitry based on the received information;
- the adaptive compression circuitry comprising:
- Fourier transform circuitry to convert the digital baseband samples into frequency-domain information for a set of received tones;
- and
- circuitry to discard a subset of the frequency-domain information, the subset of the frequency-domain information related to at least one tone of the set of received tones, and include a remaining subset of the frequency-domain information, the remaining subset of the frequency-domain information related to tones of the set of received tones other than the at least one tone, in the fronthaul uplink information, under control of the control circuitry;
- and
- the control circuitry further configured to identify the at least one tone based on the information received from the BBU;
- wherein the circuitry to discard the subset of the frequency-domain information is configured by the control circuitry to:
- discard information related to a first set of unreported tones from first frequency-domain information associated with a first time period, the first set of unreported tones included in a set of receivable tones and the set of received tones but excluded from a first set of tones;
- and
- discard information related to a second set of unreported tones from second frequency-domain information associated with a second time period, the second set of unreported tones included in the set of receivable tones and the set of received tones but excluded from a second set of tones;
- wherein the information received from the BBU comprises:
- a first tonemap descriptor, received prior to the first time period, identifying the first set of tones associated with the first time period;
- a second tonemap descriptor, received prior to the second time period, identifying the second set of tones associated with the second time period;
- and
- setup information, received prior to the first time period and the second time period, identifying the set of receivable tones;
- and
- wherein the frequency-domain information comprises the first frequency-domain information and the second frequency-domain information.