WO2024211007A1

WO2024211007A1 - Techniques for interfacing a radio frequency-interface basestation with at least one baseband digital interface radio unit

Info

Publication number: WO2024211007A1
Application number: PCT/US2024/016800
Authority: WO
Inventors: Ehsan Daeipour; Suresh N. SRIRAM
Original assignee: Commscope Technologies LLC
Current assignee: Commscope Technologies LLC
Priority date: 2023-04-05
Filing date: 2024-02-22
Publication date: 2024-10-10
Anticipated expiration: 2025-10-05
Also published as: EP4690696A1

Abstract

The present invention relates to a system communicatively coupling an RF interface base station with at least one digital baseband interface radio unit (RU) comprising: an analog RF signal/digital data converter configured (a) to convert a southbound analog RF signal to southbound time-domain digital baseband data and (b) to convert northbound time-domain digital baseband data to a northbound analog RF signal; and a digital data converter configured (a) to convert the southbound time-domain digital baseband data to southbound digital baseband data of another digital format, (b) to convert northbound digital baseband data of the other digital format to northbound time-domain digital baseband data, and (c) to be communicatively coupled to the RU.

Description

TECHNIQUES FOR INTERFACING A RADIO FREQUENCY-INTERFACE BASESTATION WITH AT LEAST ONE BASEBAND DIGITAL INTERFACE RADIO UNIT

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims benefit of U.S. Patent Application Serial No. 63/494,418 filed April 5, 2023; the entire contents of the aforementioned patent application are incorporated herein by reference as if set forth in its entirety.

BACKGROUND

[0002] A fronthaul gateway is a component of a radio access network (RAN) which facilitates connection of legacy Common Public Interface (CPRI) compliant RAN components (e.g., baseband unit(s) (BBU(s)) and/or radio unit(s)) (RU(s)) in a non- CPRI RAN implemented with switched Ethernet network(s)¹ even though use of the CPRI RAN components are not natively supported in a non-CPRI RAN. Thus, for example, CPRI compliant baseband unit(s) and/or CPRI compliant RU(s) can be connected to a RAN. The fronthaul gateway may also be used to connect 5G and/or O-RAN compliant RAN component(s)² to a RAN. Such 5G and O-RAN compliant RAN components utilize enhanced CPRI (eCPRI) in lieu of CPRI.

[0003] Because message types and formats used for CPRI and eCPRI are vendor specific, fronthaul gateways must be purchased from a vendor of the baseband unit/O- DU and radio unit/O-RU. Typically, this increases deployment costs.

SUMMARY

¹ A RAN implemented with Ethernet network(s) may be a 5G compliant and/or an Open RAN (O- RAN) compliant RAN. Specifications for O-RAN compliant RANs are promulgated by the O-RAN Alliance. CPRI is a communications interface for communicating between legacy, e.g., 4G LTE, BBU and a legacy RU.

² e.g., an O-RAN compliant distributed unit(s) (DU(s)) and/or O-RAN compliant radio unit(s) (O- RU(s)). [0004] A system is provided that is configured to communicatively couple an RF- interface base station with at least one digital baseband data interface radio unit. The system comprises: an analog RF signal / digital data converter configured (a) to convert a southbound analog RF signal received from the RF-interface base station, to southbound time-domain digital baseband data and (b) to convert northbound timedomain digital baseband data to a northbound analog RF signal and to transmit the northbound analog RF signal to the RF-interface base station; and a digital data converter configured (a) to convert southbound time-domain digital baseband data, received from the analog RF signal / digital data converter, to southbound digital baseband data of another digital format, (b) to convert northbound digital baseband data of the other digital format to the northbound time-domain digital baseband data, and (c) to be communicatively coupled, through a switched Ethernet network, to the at least one digital baseband data interface radio unit each of which is configured to receive the southbound digital baseband data of the other digital format from the digital data converter and to transmit to the digital data converter the northbound digital baseband data of the other digital format.

[0005] A method is provided for communicating southbound data in a radio access network (RAN). The method comprising: receiving a southbound analog radio frequency (RF) signal from an RF-interface base station; converting the southbound analog RF signal to southbound time-domain digital baseband data; converting the southbound time-domain digital baseband data to southbound digital baseband data in another digital format; and transmitting the southbound digital baseband data in the other digital format through a switched Ethernet network to at least one digital baseband interface radio unit.

[0006] A method is provided for communicating northbound data in a radio access network (RAN). The method comprises: receiving northbound digital baseband data in a digital format through a switched Ethernet network from at least one digital baseband interface radio unit; converting the northbound digital baseband data in the digital format to northbound time-domain digital baseband data; converting the northbound time-domain digital baseband data to a northbound analog RF signal; and transmitting the northbound analog RF signal to an RF-interface base station.

BRIEF DESCRIPTION OF THE DRAWINGS [0007] Understanding that the drawings depict only exemplary configurations and are not therefore to be considered limiting in scope, the exemplary configurations will be described with additional specificity and detail through the use of the accompanying drawings, in which:

[0008] FIG. 1 A illustrates a block diagram of one embodiment of a radio access network configured to communicatively couple an antenna port of a radio frequencyinterface base station to a frequency-domain digital data interface radio unit;

[0009] FIG. IB illustrates a block diagram of an embodiment of a radio access network configured to communicatively couple an antenna port of a radio frequencyinterface base station to a time-domain digital data interface radio unit; and [0010] FIG. 1C illustrates a block diagram of one embodiment of a radio access network configured to communicate a single stream of northbound frequency-domain baseband digital data and a single stream of southbound frequency-domain digital data between at least two frequency-domain digital baseband data interface radio unit radio units, communicatively coupled in parallel to a time domain / frequency domain converter;

[0011] FIG. ID illustrates a block diagram of one embodiment of a radio access network configured to communicate a single stream of northbound frequency-domain baseband digital data and a single stream of southbound frequency-domain digital data between at least two frequency-domain digital baseband data interface radio unit radio units communicatively coupled in series with one another;

[0012] FIG. 2 is a flow diagram illustrating a method for communicatively coupling southbound data from a radio frequency-interface base station to at least one digital baseband data interface radio unit; and

[0013] FIG. 3 is a flow diagram illustrating a method for communicatively coupling northbound data from a digital baseband data interface radio unit to a radio frequency - interface base station.

[0014] In accordance with common practice, the various described features are not drawn to scale but are drawn to emphasize specific features relevant to the exemplary configurations.

DETAILED DESCRIPTION

[0015] Techniques are provided for communicatively coupling data between a radio frequency (RF)-interface base station and at least one RU communicatively coupled to the RF-interface base station. Depending on which of the following embodiments is used, each RU is configured to be a legacy RU or a non-legacy RU, e.g., an O-RU. Optionally, the non-legacy RU, e.g., the O-RU, is configured to transmit and receive RF analog signals using a legacy, e.g., fourth generation Long Term Evolution (4G LTE), air interface. As used herein, the term “north” or “northbound” means “upstream” or away from an RU, while the term and the term “south” or “southbound” means “downstream” or towards the RU.

[0016] A fronthaul gateway (FHG) and an analog radio frequency (RF) signal / digital data converter are provided. The FHG includes a digital data converter. Optionally, the FHG also includes the analog RF signal / digital data converter. Therefore, embodiments of the invention will be described with respect to the analog RF signal / digital data converter and the digital data converter.

[0017] A first port of the analog RF signal / digital data converter is communicatively coupled to an antenna port of RF-interface base station. A second port of the analog RF signal / digital data converter is communicatively coupled to a first port of the digital data converter. A second port of the digital data converter is configured to be communicatively coupled to a switched Ethernet network.

[0018] Digital data converter means a data converter which converts southbound baseband digital data in a first data format (e.g., time-domain digital baseband data) to southbound digital baseband data in a second data format, and coverts northbound digital baseband data in the second data format to northbound digital baseband data in the first data format (e.g., time-domain digital baseband data). As further illustrated herein, optionally, the digital data converter may be a time domain / frequency domain converter or an, e.g., first, time-domain digital data encapsulator / decapsulator.

[0019] The analog RF signal / digital data converter is configured to convert a southbound analog RF signal to southbound time-domain digital data, and northbound time-domain digital data to northbound analog RF signals. The southbound analog RF signals and the northbound analog RF signals are configured to be respectively transmitted from and received by the antenna port of the RF-interface base station. The southbound time-domain digital data and the northbound time-domain digital data are configured to be respectively received by and transmitted from the digital data converter. Optionally, in embodiments of the invention including related to a system or a method, the southbound (time- or frequency- domain) digital baseband data and the northbound (time- or frequency- domain) digital baseband data respectively are southbound (time- or frequency- domain) in-phase and quadrature phase (IQ) digital baseband data and the northbound time- or frequency- domain) IQ digital baseband data.

[0020] The digital data converter may be a time domain / frequency domain digital data converter or a time domain digital data encapsulator / decapsulator. The time domain / frequency domain digital converter is configured to covert southbound timedomain digital baseband data to southbound frequency-domain digital baseband data, and northbound frequency-domain digital baseband data to northbound time-domain digital baseband data. Optionally, when southbound time-domain IQ digital baseband data and the northbound time-domain IQ digital baseband data are respectively received by and transmitted from the digital data converter, then the southbound frequency-domain digital baseband data and northbound frequency-domain digital baseband data are respectively southbound frequency-domain IQ digital baseband data and the northbound frequency-domain IQ digital baseband data.

[0021] The southbound time-domain digital baseband data and the northbound time-domain digital data are configured to be respectively transmitted by and received by the analog RF / digital converter. The southbound frequency-domain digital baseband data and the northbound frequency-domain digital data are configured to be respectively received by and transmitted from the switched Ethernet network.

[0022] The time domain digital data encapsulator / decapsulator is configured to encapsulate southbound time-domain digital baseband data into eCPRI frame(s) (of data) and to decapsulate northbound time-domain digital baseband data from eCPRI frame(s) (of data). The southbound time-domain digital baseband data and the northbound time-domain digital baseband data are configured to be respectively provided by and received by the analog RF signal / digital data converter. The southbound eCPRI frames (of data) and the eCPRI frames (of data) are configured to be respectively received by and transmitted from the switched Ethernet network. Optionally, the eCPRI frame (of data) may be compliant with the Institute of Electrical and Electronics Engineers standard P1904.3 pertaining to Radio over Ethernet (RoE).

[0023] The frames of data, e.g, eCPRI frames of data, communicated in the RAN (e.g., over switched Ethernet network(s)) are time synchronized using synchronization data. Such synchronization data may be derived using different techniques. Synchronization data may be derived from frame boundaries in a downlink analog RF signal from an RF-interface base station or from timing data (e.g., Network Time Protocol (NTP) or Precision Time Protocol (PTP) data). Optionally, such time data may be provided by, e.g., a CPRI BBU, an RF-interface base station, or a clock communicatively coupled to the RAN. If timing data is used, then optionally, the RAN includes a timing client used to extract time from the timing data.

[0024] The following description applies to embodiments of the systems and methods herein. Each digital baseband data interface RU is configured to receive and transmit time- or frequency- domain digital baseband, e.g., IQ, data respectively at and from a digital baseband data interface, e.g., respectively a TDI or an FDI, of the digital baseband data interface RU. Such digital baseband data, transmitted by the digital baseband data interface, is generated from an analog RF signal received, e.g., from UE, through an antenna port of the digital baseband interface RU. Such received digital baseband data, received by the digital baseband data interface, is converted to an analog RF signal (including data) and transmitted from the antenna port of the digital baseband data interface RU, e.g., to UE. Each of the at least one digital baseband data interface RU may be a frequency-domain digital baseband data interface (FDI) radio unit or a time-domain digital baseband data interface (TDI) radio unit. The data of a southbound analog RF signal transmitted from an antenna port of a digital baseband data interface RU and southbound digital baseband data is derived from data of a southbound analog RF signal received from the RF-interface base station. The data of a northbound analog RF signal received by the RF-interface base station and northbound digital baseband data is derived from data of the analog RF signal received by an antenna port of a digital baseband data interface RU.

[0025] FIG. 1 A illustrates a block diagram of one embodiment of a radio access network 100 A configured to communicatively couple an antenna port of a RF- interface base station to a frequency-domain digital data interface (FDI) radio unit. Optionally, the FDI is configured to use eCPRI; however, the FDI may use another type of digital data protocol. Optionally, the FDI radio unit is a non-legacy RU, e.g., an 0-RU or a 5G compliant radio each of which configured to transmit and receive RF analog signals using a legacy air interface, e.g., 4G LTE. Optionally, each of the radio access networks described herein may be implemented with aspects of the methods described herein. [0026] The RAN 100 A includes an RF -interface base station 102a, an analog RF signal / digital data converter 104 A, a time domain / frequency domain converter 104B, a switched Ethernet network 108, and an FDI radio unit 106. For pedagogical reasons, only one FDI radio unit 106 is illustrated as being communicatively coupled to the switched Ethernet network 108; however, in other embodiments, more than one FDI radio unit may be communicatively coupled to the switched Ethernet network 108. The switched Ethernet network 108 as used herein may also be referred to as a switched Ethernet fronthaul network. The switched Ethernet network 108 includes one or more set of electrical conductors, e.g., Ethernet cable(s), and one or more Ethernet switches. The RAN 100A also optionally includes a CPRI BBU 102b and a CPRI converter 104C.

[0027] A fronthaul gateway (FHG) 104 includes the digital data converter that is the time domain / frequency domain converter 104B. The time domain / frequency domain converter 104B is configured to convert (a) southbound time-domain baseband digital data to southbound frequency-domain baseband digital data 114 A, and (b) northbound frequency-domain baseband digital data 114B to northbound time-domain digital baseband data. Optionally, the time domain / frequency domain converter 104B is implemented with a Fourier transform of southbound (or downlink) data and an inverse Fourier transform of northbound (or uplink) data; optionally, such transforms may be implemented with digital signal processing circuitry.

[0028] Optionally, the FHG 104 also includes the analog RF signal / digital data converter 104 A; alternatively, the analog RF signal / digital data converter 104 A may be communicatively coupled between the RF-interface base station 102a and the FHG 104, e.g., the time domain / frequency domain converter 104B. The analog RF signal / digital data converter 104A is configured to convert a southbound analog RF signal (including data) 110A to southbound time-domain digital baseband data 112A and northbound time-domain digital baseband data 112B to a northbound analog RF signal (including data) HOB. Optionally, the analog RF signal / digital data converter 104A is implemented with at least one analog to digital converter(s) for southbound (or downlink) traffic and with digital to analog converter(s) for northbound (or uplink) traffic. The FHG 104 is configured to communicatively couple the analog RF signal / digital data converter 104 A or RF-interface base station 102a with the switched Ethernet network 108 and to, at least, perform the functionality of the time domain / frequency domain data converter 104B. [0029] The FHG 104 optionally includes the optional CPRI converter 104C; alternatively, the optional CPRI converter 104C may be communicatively coupled between the CPRI BBU 102B and the FHG 104, e.g., the time domain / frequency domain converter 104B. The CPRI converter 104C is configured to convert CPRI frames of data 190 A to southbound time-domain digital baseband data 192 A and northbound time-domain digital baseband data 192B to a northbound CPRI frames of data 190B. Optionally, the CPRI converter 104C is configured to perform resampling, e.g., of the northbound time-domain digital baseband data and/or the southbound time-domain digital baseband data. The FHG 104 is configured to communicatively couple the CPRI converter 104C or the CPRI BBU 102b with the switched Ethernet network 108 and to, at least, perform the functionality of the time domain / frequency domain data converter 104B.

[0030] Data communications can be facilitated between the CPRI BBU 102b and the FDI RU 106. However, for pedagogical purposes, only communications between the RF -interface base station 102a and the FDI RU 106 are illustrated herein.

[0031] Each radio unit described with respect to the embodiments disclosed herein is electrically connected to a set of one or more antennas 106A; each such radio unit is configured to transmit and receive analog RF signals though such one or more antennas 106 A respectively to and from at least one user equipment (UE) 118 in a coverage area 116 of such one or more antennas 106 A and radio unit. For pedagogical purposes, the figures herein illustrate only one radio unit and one UE; however, more than one radio unit may be employed and/or more than one UE may be in a coverage area of a radio unit and transmit and receive RF analog signals respectively to and from the radio unit.

[0032] A first port 104A-1 of the analog RF signal / digital data converter 104 A is configured to be communicatively coupled to an antenna port 102a-l of the RF- interface base station 102a. If it were not communicatively coupled to the analog RF signal / digital data converter 104 A, the antenna port 102a-l of the RF -interface base station 102a would be coupled to one or mor antennas. A second port 104A-2 of the analog RF / digital data converter 104A is configured to be communicatively coupled to a first port 104B-2 of the time domain / frequency domain digital data converter (time domain / frequency domain converter) 104B. A second port 104B-2 of the time domain / frequency domain data converter 104B is configured to be communicatively coupled to the switched Ethernet network 108. [0033] The FDI RU 106 is configured to transmit and receive, through the set of one or more antennas 106A, analog RF signals respectively to and from at least one UE 118. The FDI RU 106 includes a FDI port 106B configured to be communicatively coupled to the switched Ethernet network 108. The FDI RU 106 is configured to transmit and receive, through the set of one or more antennas 106 A, analog RF signals respectively to and from at least one UE 118. The FDI RU 106 is configured to:

(a) receive southbound frequency-domain baseband digital data, from the switched Ethernet network, at the FDI port 106B and convert the southbound frequency-domain baseband digital data to a downlink analog RF signal (including data) configured to be transmitted from the FDI RU 106, e.g., through (and radiated by) the at least one antenna 106 A electrically coupled to the FDI RU 106; and

(b) receive an uplink analog RF signal (including data), e.g., through the at least one antenna 106 A electrically coupled to the FDI RU 106, and convert the uplink analog RF signal to a northbound frequency-domain baseband digital data configured to be transmitted from the FDI port 106B to the switched Ethernet network 108. [0034] FIG. IB illustrates a block diagram of an embodiment of a radio access network 100B configured to communicatively couple an antenna port of a RF- interface base station to a time-domain digital data interface (TDI) radio unit. The illustrated embodiment of FIG. IB is implemented and operates similar to the illustrated embodiment of FIG. 1A, except that the embodiment of FIG. IB is configured to communicate northbound and southbound time-domain digital baseband data between the analog RF signal / digital data converter 104 A and at least one TDI radio unit and that such northbound and southbound time-domain digital baseband data is conveyed in eCPRI frame through the switched Ethernet network 108. Except as otherwise described herein, elements of FIG. IB having the same or similar element numbers as elements of FIG. 1 A are configured to be implemented, to operate, and/or be like their same or similar counterparts in FIG. 1 A. Data communications can be facilitated between the CPRI BBU 102b and the FDI RU 106. However, for pedagogical purposes, only communications between the RF-interface base station 102a and the FDI RU 106 are illustrated herein.

[0035] Optionally, the TDI is configured to use CPRI; however, the RDI may use another type of digital data protocol. Optionally, the TDI radio unit is a legacy RU configured to transmit and receive analog RF signals using a legacy air interface, e.g., 4G LTE.

[0036] The RAN 100B includes the RF -interface base station 102a, the analog RF signal / digital data converter 104 A, a first time-domain digital data encapsulator / decapsulator 104B’, the switched Ethernet network 108, a second time-domain digital data encapsulator / decapsulator 105, and a TDI radio unit 106’. For pedagogical reasons, only one TDI radio unit 106’ is illustrated as being communicatively coupled to the switched Ethernet network 108; however, in other embodiments, more than one TDI radio unit may be communicatively coupled to the switched Ethernet network 108.

[0037] A fronthaul gateway (FHG) 104 includes the digital data converter that is the first time-domain digital data encapsulator / decapsulator 104B’. The first timedomain digital data encapsulator / decapsulator 104B’ is configured to configured to encapsulate southbound time-domain digital baseband data, from the analog RF signal / digital data converter 104A, into southbound eCPRI frames (of data) 103 A and to decapsulate, i.e., extract, northbound time-domain digital band data from northbound eCPRI frames (of data) 103B. The decapsulated northbound time-domain digital baseband data is configured to be transmitted to the analog RF signal / digital data converter 104A. The southbound eCPRI frames (of data) 103 A are configured to be transmitted to the switched Ethernet network 108.

[0038] Optionally, the FHG 104 also includes the analog RF signal / digital data converter 104 A; alternatively, the analog RF signal / digital data converter 104 A may be communicatively coupled between the RF-interface base station 102a and the FHG 104, e.g., the first time-domain digital data encapsulator / decapsulator 104B’. The analog RF signal / digital data converter 104A is configured to convert a southbound analog RF signal (including data) to time-domain digital baseband data and northbound time-domain digital baseband data to a northbound analog RF signal (including data). Optionally, the analog RF signal / digital data converter 104A is implemented with at least one analog to digital converter(s) for southbound (or downlink) traffic and with digital to analog converter(s) for northbound (or uplink) traffic.

[0039] The analog RF signal / digital data converter 104 A and the RF-interface base station 102a are configured to be implemented and operated as described with respect to FIG. 1 A, except that the second port 104A-2 of the analog RF signal / digital data converter 104A is configured to be communicatively coupled to a first port 104B’-2 of the first time-domain digital data encapsulator / decapsulator 104B’. A second port 104B’-2 of the first time-domain digital data encapsulator / decapsulator 104B’ is configured to be communicatively coupled to the switched Ethernet network 108. [0040] The second time-domain digital data encapsulator / decapsulator 105 is comprises a first port 105 A and a second port 105B. The first port 105 A, of the second time-domain digital data encapsulator / decapsulator 105, is configured to be communicatively coupled to the switched Ethernet network 108. The second port 105B, of the second time domain / frequency domain encapsulator / decapsulator 105, is configured to be communicatively coupled to the TDI RU 106’. The second time domain / frequency domain encapsulator / decapsulator 105 is configured to decapsulate, z.e., extract, southbound time-domain digital baseband data 107 A from southbound eCPRI frames (of data) 103 A received from the switched Ethernet network 108 and to encapsulate northbound time-domain digital baseband data 107B, received the TDI RU 106’, into northbound eCPRI frames (of data) 103B. The decapsulated southbound time-domain digital baseband data is configured to be transmitted to the TDI RU 106’, e.g., a TDI port 106’B of the TDI RU 106’. The northbound eCPRI frames (of data) are configured to be transmitted to the switched Ethernet network 108.

[0041] The TDI RU 106’ includes the TDI port 106’B configured to be communicatively coupled to the second port 105B of the second time-domain digital data enscapsulator / decapsulator 105. The TDI RU 106’ is configured to transmit and receive, through the set of one or more antennas 106A, analog RF signals respectively to and from at least one UE 118. The TDI RU 106’ is configured to:

(c) receive southbound time-domain baseband digital data, from the second time-domain digital data encapsulator / decapsulator 105, at the TDI port 106’B and convert the southbound time-domain baseband digital data to a downlink analog RF signal (including data) configured to be transmitted from the TDI RU 106’, e.g., through (and radiated by) the at least one antenna 106 A electrically coupled to the TDI RU 106’; and

(d) receive an uplink analog RF signal (including data), e.g., through the at least one antenna 106A electrically coupled to the TDI RU 106’, and convert the uplink analog RF signal to a northbound frequency-domain baseband digital data configured to be transmitted from the TDI port 106’B to the second time-domain digital data encapsulator / decap sulator 105.

[0042] FIG. 1C illustrates a block diagram of one embodiment of a radio access network 100C configured to communicate a single stream of northbound frequencydomain baseband digital data and a single stream of southbound frequency-domain digital data between at least two frequency-domain digital baseband data interface (FDI) radio unit radio units, communicatively coupled in parallel to a time domain / frequency domain converter. The illustrated embodiment of FIG. 1C is implemented and operates similar to the illustrated embodiment of FIG. 1 A, except that the embodiment of FIG. 1C is configured to implement a “shared cell” configuration implemented with fronthaul multiplexing.³ Except as otherwise described herein, elements of FIG. 1C having the same or similar element numbers as elements of FIG. 1 A are configured to be implemented, to operate, and/or be like their same or similar counterparts in FIG. 1 A. Data communications can be facilitated between the CPRI BBU 102b and the FDI RU 106. However, for pedagogical purposes, only communications between the RF-interface base station 102a and the FDI RU 106 are illustrated herein.

[0043] However, a second port of the time / frequency domain converter 104B, or the FHG 104, is communicatively coupled to a fronthaul multiplexer (FHM) 108 A. The switched Ethernet network 108 my comprise the FHM 108 A, or alternatively the FHM 108 A may be communicatively coupled between the time / frequency domain converter 104B (or the FHG 104) and the switched Ethernet network 108. For pedagogical purposes, FIG. 1C illustrates that the switched Ethernet network includes the FHM 108 A. A fronthaul multiplexing mode and a Cascade mode are two “shared cell’ configurations, described in the O-RAN specifications, in which a single cell is

³ A fronthaul multiplexing mode and a Cascade mode are two “shared cell’ configurations, described in the O-RAN specifications, in which a single cell is served using two or more RUs. The O-RAN shared cell implementation attempts to make more efficient use of bandwidth to and from O-RAN compliant distributed units (DUs or O-DUs) in order to support communicating front-haul data with the two or more RUs. The O-RAN shared cell implementation is described in detail at Section 13 “Support of Shared Cell” in the O-RAN Working Group 4 (Open Fronthaul Interfaces WG) Control, User and Synchronization Plane Specification version 10.0 from October 2022 (O-RAN. WG4.CUS.0-vl0.00, hereinafter “Support of Shared Cell O-RAN Specification”, available at pages 252-270 of PDF at https Aomi fc jAiads eb .azure websites, which is hereby incorporated by reference in its entirety.

served using two or more FDI RUs 106-1, 106-N. Figure 1C pertains to the fronthaul multiplexing mode.

[0044] The shared cell concept may be implemented with an RF -interface base station 102a. Returning to FIG. 1C, the shared cell 110 comprises at least two FDI RUs 106-1, 106-N communicatively coupled in parallel to the switched Ethernet network 108. The FHM 108 A performs the functionality described for the RF- interface base station rather than an O-RAN compliant distributed unit.

[0045] The digital data converter that is a time domain / frequency domain converter 104B is communicatively coupled, through either the FHM 108 A communicatively coupled to the switched Ethernet network 108 or the switched Ethernet network 108 comprising the FHM 108 A, to the at least one digital baseband data interface radio unit comprising at least two FDI RUs 106-1, 106-N. Each FDI radio unit each of which is configured to receive a same stream of southbound frequency-domain digital baseband data 101-1, 101 -N from the FHM 108 A. The FHM 108 A which is configured to combine streams of northbound frequency-domain digital baseband data 109-1, 109-N received from each of the at least two FDI radio units 106-1, 106-N into a single stream of northbound frequency-domain digital baseband data 114B’ and to transmit the single stream of northbound frequencydomain digital baseband data 114B‘ to the time domain / frequency domain converter 104B.

[0046] To accomplish the foregoing, the FHM 108A : (1) replicates a stream of southbound (or downlink) frequency-domain digital baseband data 114 A’ (from the time domain / frequency domain converter 104B) into separate streams of southbound frequency-domain digital baseband data 101-1, 101 -N transmitted by the FHM 108 A to each FDI RU 106-1, 106-N in the shared cell 110; and (2) uses combining/digital summation of separate streams of northbound frequency-domain digital baseband data 109-1, 109-N to form a single stream of northbound (or uplink) frequency-domain digital baseband data 114B’ transmitted by the FHM 108 A (to the time domain / frequency domain converter 104B). When IQ data is used, the combining/digital summation includes: (1) adding the corresponding in-phase (I) samples in corresponding physical resource blocks (PRBs) (from all the FDI RUs 106-1, 106-N); (2) adding the corresponding quadrature-phase (Q) samples in corresponding PRBs (from all the FDI RUs 106-1, 106-N); and (3) sending a combined stream of IQ data from the FHM 108 A to the time domain / frequency domain converter 104B. The combining/digital summation may optionally include some overflow management. Using the shared cell implementation, the time domain / frequency domain converter 104B can send and receive a single frequency-domain baseband digital data stream north- and south- bound (with a bandwidth of approximately N PRBs) instead of M data streams (one for each FDI RU with a total bandwidth of approximately N PRBs x M FDI RUs). By reducing transmitted and received data to a single stream of N PRBs, the shared cell implementation reduces bandwidth utilized in the switched Ethernet network 108.

[0047] FIG. ID illustrates a block diagram of one embodiment of a radio access network 100D configured to communicate a single stream of northbound frequencydomain baseband digital data and a single stream of southbound frequency-domain digital data between at least two frequency-domain digital baseband data interface (FDI) radio unit radio units communicatively coupled in series with one another. The illustrated embodiment of FIG. ID is implemented and operates similar to the illustrated embodiment of FIG. 1 A, except that the embodiment of FIG. ID is configured to implement a “shared cell” configuration implemented with the Cascade mode. Except as otherwise described herein, elements of FIG. ID having the same or similar element numbers as elements of FIG. 1 A are configured to be implemented, to operate, and/or be like their same or similar counterparts in FIG. 1 A.

Communications can be facilitated between the CPRI BBU 102b and the FDI RU 106. However, for pedagogical purposes, only communications between the RF- interface base station 102a and the FDI RU 106 are illustrated herein.

[0048] In the Cascade mode, the FDI RUs 106-1, 106-N are arranged in a daisychain. The digital data converter is a time domain / frequency domain converter 104B communicatively coupled, through the switched Ethernet network 108, to at least one digital baseband data interface radio unit. The at least one digital baseband data interface radio unit comprises (a) a first FDI radio unit 106-1 communicatively coupled to the switched Ethernet network 108 and (b) a second FDI radio unit 106-N that is subtended from the first FDI radio unit 106-1 and communicatively coupled to the switched Ethernet network 108 through the first FDI radio unit 106-1. The first FDI radio unit 106-1 transmits southbound frequency-domain digital baseband data 115A (received by the first FDI radio unit 106-1) to the second FDI radio unit 106-N. The first FDI radio unit 106-1 also combines northbound frequency-domain digital baseband data 117 of the first FDI radio 106-1 with northbound frequency-domain digital baseband data 115B received from the second FDI radio unit 106-N and transmits, through the switched Ethernet network 108, combined northbound frequency-domain digital baseband data 114B” to the time domain / frequency domain converter 104B.

[0049] To accomplish the foregoing, each FDI RU which has another FDI RU subtended from it, includes copy-and-forward and combine-and-forward functionality. FDI RUs, operating in the Cascade mode, act as copy-and-forward nodes for southbound (or downlink) frequency-domain digital baseband data. Thus, an FDI RU, which has another FDI RU subtended from it, (a) copies the southbound frequency-domain digital baseband data received by it and originally received from the switched Ethernet network 108 and (b) forwards (or transmits) the copied data to the other FDI RU that is subtended from the FDI RU.

[0050] FDI RUs, operating in the Cascade mode, act as combine-and-forward nodes for northbound (or uplink) frequency-domain digital baseband data 115B, 117. Thus, an FD RU, which has another FDI RU subtended from it, (a) combines/performs digital summation on northbound frequency-domain digital baseband data 117 generated by the FDI RU and northbound frequency-domain digital baseband data 115B received from the other FDI RU subtended from the FD RU, and (b) forwards the combined northbound frequency-domain digital baseband data 114B” to either the switched Ethernet network 108 (if there are no intervening FDI RU(s)) between the FDI RU and the switched Ethernet network 108) or to yet another FDI RU from which the FDI RU is subtended.

[0051] When IQ data is used, the combining/digital summation includes: (1) adding the corresponding in-phase (I) samples in corresponding physical resource blocks (PRBs) (generated by the FDI RU and received from the other FDI RU subtended from the FDI RU); (2) adding the corresponding quadrature-phase (Q) samples in corresponding PRBs (generated by the FDI RU and received from the other FDI RU subtended from the FDI RU); and (3) transmitting a combined stream of I/Q data from the FDI RU to the switched Ethernet network 108 (if there are no intervening FDI RU(s)) between the FDI RU and the switched Ethernet network 108) or to yet another FDI RU from which the FDI RU is subtended. The combining/digital summation may optionally include some overflow management.

[0052] Each element of FIGS 1A-1D, and any of the specific features described here as being implemented thereby, can be implemented in hardware, software, or combinations of hardware and software, and the various implementations (whether hardware, software, or combinations of hardware and software) can also be referred to generally as “circuitry,” a “circuit,” or “circuits” that is or are configured to implement at least some of the associated functionality. When implemented in software, such software can be implemented in software or firmware executing on one or more suitable programmable processors (or other programmable device) or configuring a programmable device (for example, processors or devices included in or used to implement special-purpose hardware, general-purpose hardware, and/or a virtual platform). In such a software example, the software can comprise program instructions that are stored (or otherwise embodied) on or in an appropriate non- transitory storage medium or media (such as flash or other non-volatile memory, magnetic disc drives, and/or optical disc drives) from which at least a portion of the program instructions are read by the programmable processor or device for execution thereby (and/or for otherwise configuring such processor or device) in order for the processor or device to perform one or more functions described here as being implemented the software. Such hardware or software (or portions thereof) can be implemented in other ways (for example, in a field programmable gate array (FPGA), application specific integrated circuit (ASIC), etc.).

[0053] Moreover, each RU, can be implemented as a physical network function (PNF) (for example, using dedicated physical programmable devices and other circuitry) and/or a virtual network function (VNF) (for example, using one or more general purpose servers (possibly with hardware acceleration) in a scalable cloud environment and in different locations within an operator’s network (for example, in the operator’s “edge cloud” or “central cloud”). Each VNF can be implemented using hardware virtualization, operating system virtualization (also referred to as containerization), and application virtualization as well as various combinations of two or more the preceding. Where containerization is used to implement a VNF, it may also be referred to as a “containerized network function” (CNF). For example, in the exemplary embodiment shown in Figures 1 A-1D, each RU is implemented as a PNF and is deployed in or near a physical location where radio coverage is to be provided. Each RU and any of the specific features described here as being implemented thereby, can be implemented in other ways.

[0054] Each UE 118-1, 118-N may be a computing device with at least one processor that executes instructions stored in memory, e.g., a mobile phone, tablet computer, mobile media device, mobile gaming device, laptop computer, vehiclebased computer, a desktop computer, etc.

[0055] Each RU and the RF-interface base station 102a can be implemented so as to use an air interface that supports one or more of frequency-division duplexing (FDD) and/or time-division duplexing (TDD). Also, the RUs and the RF-interface base station can be implemented to use an air interface that supports one or more of the multiple-input-multiple-output (MIMO), single-input-single-output (SISO), single- input-multiple-output (SIMO), and/or beam forming schemes. Moreover, the RANs 100A-D can be configured to support multiple air interfaces.

[0056] FIG. 2 is a flow diagram illustrating a method 200 for communicatively coupling southbound data from an RF-interface base station to at least one digital baseband data interface RU. Optionally, method 200 may be implanted using one of the RANs 100A-D illustrated in FIGS. 1 A-1D and the techniques described therefor; alternatively, method 200 may be implemented with a different RAN implementation. The blocks of the flow diagram shown in Figure 2 have been arranged in a generally sequential manner for ease of explanation; however, it is to be understood that this arrangement is merely exemplary, and it should be recognized that the processing associated with method 200 (and the blocks shown in Figure 2) can occur in a different order (for example, where at least some of the processing associated with the blocks is performed in parallel and/or in an event-driven manner).

[0057] In block 200 A, a southbound analog RF signal (e.g., from an RF-interface base station 102a) is received, e.g., by an analog RF signal / digital data converter 104A. In block 200B, the southbound analog RF signal is converted (e.g., by the analog RF / digital converter 104 A) to southbound digital time-domain baseband data. [0058] In block 200C, the southbound digital time-domain baseband data is converted (e.g., by a digital data converter) into southbound digital baseband data of another digital format. Optionally, the southbound digital time-domain baseband data is converted (e.g., by the digital data converter that is a time domain / frequency domain converter 104B) into digital frequency-domain baseband data. Alternatively and optionally, the southbound digital time-domain data is encapsulated (e.g., by the digital data converter that is a first time-domain digital data encapsulator / decapsulator 104B’) into eCPRI frames, e.g., O-RAN frames.

[0059] In block 200D, the southbound digital baseband data in the other digital format is transmitted to at least one radio unit, e.g., through a switched Ethernet network. Optionally, the southbound digital baseband data in the other digital format is transmitted to at least two radio units of a shared cell using a FHM mode or a cascade mode, and where the southbound baseband data in the other digital format is southbound digital frequency-domain baseband data. Optionally, each radio unit converts the southbound digital baseband data in the other digital format to another (downlink) RF analog signal (including data) which is transmitted from an antenna port of the corresponding radio unit.

[0060] FIG. 3 is a flow diagram illustrating a method 300 for communicatively coupling northbound data from a digital baseband data interface RU to an RF- interface base station. Optionally, method 300 may be implanted using one of the RANs 100A, 100B, 100C, 100D illustrated in FIGS. 1A-1D and the techniques described therefor; alternatively, method 300 may be implemented with a different RAN implementation. The blocks of the flow diagram shown in Figure 3 have been arranged in a generally sequential manner for ease of explanation; however, it is to be understood that this arrangement is merely exemplary, and it should be recognized that the processing associated with method 300 (and the blocks shown in Figure 3) can occur in a different order (for example, where at least some of the processing associated with the blocks is performed in parallel and/or in an event-driven manner). [0061] In block 300A, northbound baseband digital data in a digital format is transmitted to an RF -interface base station, e.g., through a switched Ethernet network, from at least one radio unit. Optionally, the northbound baseband digital data in the digital format is either northbound frequency-domain digital baseband data or timedomain digital baseband data encapsulated in eCPRI frames. Optionally, the northbound digital baseband data in the digital format is transmitted by at least two radio units of a shared cell using a FHM mode or a cascade mode, and where the northbound baseband data in the digital format is northbound digital frequencydomain baseband data. Optionally, each radio unit converts another (uplink) RF analog signal (including data), received through an antenna port of the corresponding radio unit, to the northbound digital baseband data in the other digital format to another (downlink) RF analog signal (including data).

[0062] In block 300B, the northbound digital baseband data in the digital format is converted (e.g., by a digital data converter) into northbound time-domain digital baseband data. Optionally, the northbound digital baseband data in a digital format is northbound frequency-domain digital data (and e.g., the digital data converter is a time domain / frequency domain converter 104B). Alternatively and optionally, the northbound baseband data in a digital format is time-domain baseband data encapsulated into eCPRI frames (and e.g., the digital data converter is a first timedomain digital data encapsulator / decapsulator 104B’).

[0063] In block 300C, the northbound time-domain digital baseband data is converted, e.g., by an analog RF signal / digital data converter 104 A, to a northbound analog RF signal. In block 300D, the northbound analog RF signal is transmitted to the RF-interface base station.

Terminology

[0064] Brief definitions of terms, abbreviations, and phrases used throughout this application are given below.

[0065] The term “determining” and its variants may include calculating, extracting, generating, computing, processing, deriving, modeling, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like. Also, “determining” may also include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory) and the like. Also, “determining” may include resolving, selecting, choosing, establishing and the like.

[0066] The phrase “based on” does not mean “based only on,” unless expressly specified otherwise. In other words, the phrase “based on” describes both “based only on” and “based at least on”. Additionally, the term “and/or” means “and” or “or”. For example, “A and/or B” can mean “A”, “B”, or “A and B”. Additionally, “A, B, and/or C” can mean “A alone,” “B alone,” “C alone,” “A and B,” “A and C,” “B and C” or “A, B, and C.”

[0067] The terms “connected”, “coupled”, and “communicatively coupled” and related terms may refer to direct or indirect connections. If the specification states a component or feature “may,” “can,” “could,” or “might” be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.

[0068] The terms “responsive” or “in response to” may indicate that an action is performed completely or partially in response to another action. The term “module” refers to a functional component implemented in software, hardware, or firmware (or any combination thereof) component.

[0069] The methods disclosed herein comprise one or more actions for achieving the described method. Unless a specific order of steps or actions is required for proper operation of the method that is being described, the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims. [0070] While detailed descriptions of one or more configurations of the disclosure have been given above, various alternatives, modifications, and equivalents will be apparent to those skilled in the art without varying from the spirit of the disclosure. For example, while the configurations described above refer to particular features, functions, procedures, components, elements, and/or structures, the scope of this disclosure also includes configurations having different combinations of features, functions, procedures, components, elements, and/or structures, and configurations that do not include all of the described features, functions, procedures, components, elements, and/or structures. Accordingly, the scope of the present disclosure is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the claims, together with all equivalents thereof. Therefore, the above description should not be taken as limiting.

EXAMPLES

[0071] Example 1 includes a system configured to communicatively couple an RF- interface base station with at least one digital baseband data interface radio unit, the system comprising: an analog RF signal / digital data converter configured (a) to convert a southbound analog RF signal received from the RF-interface base station, to southbound time-domain digital baseband data and (b) to convert northbound timedomain digital baseband data to a northbound analog RF signal and to transmit the northbound analog RF signal to the RF-interface base station; and a digital data converter configured (a) to convert southbound time-domain digital baseband data, received from the analog RF signal / digital data converter, to southbound digital baseband data of another digital format, (b) to convert northbound digital baseband data of the other digital format to the northbound time-domain digital baseband data, and (c) to be communicatively coupled, through a switched Ethernet network, to the at least one digital baseband data interface radio unit each of which is configured to receive the southbound digital baseband data of the other digital format from the digital data converter and to transmit to the digital data converter the northbound digital baseband data of the other digital format.

[0072] Example 2 includes the system of Example 1, wherein the digital data converter is configured to be communicatively coupled, through the switched Ethernet network, to the at least one digital baseband data interface radio unit comprises the digital data converter is configured to be communicatively coupled, through the switched Ethernet network of an open radio access network, to the at least one digital baseband data interface radio unit each of which is an open radio access network radio unit.

[0073] Example 3 includes the system of any of Examples 1-2, wherein the digital data converter is configured to be communicatively coupled, through the switched Ethernet network, to the at least one digital baseband data interface radio unit each of which is a frequency-domain digital baseband data interface (FDI) radio unit configured to receive southbound frequency-domain digital baseband data and to transmit northbound frequency-domain digital baseband data through the switched Ethernet network to the digital data converter; wherein the digital data converter is a time domain / frequency domain converter and digital baseband data in the other digital format is time-domain digital baseband data.

[0074] Example 4 includes the system of any of Examples 1-3, wherein the digital data converter is a first time-domain digital data encapuslator / decapsulator converter configured to encapsulate the southbound time-domain digital baseband data, from the analog RF signal / digital data converter, into southbound enhanced common public radio interface (eCPRI) frames and to extract the northbound time-domain digital baseband data from northbound eCPRI frames provided to the analog RF signal / digital data converter; and wherein the other digital format is eCPRI frames; wherein the digital data converter is configured to be communicatively coupled, through the switched Ethernet network, to the at least one digital baseband data interface radio unit each of which is a time-domain digital baseband data interface (TDI) radio unit configured to receive decapsulated southbound time-domain digital baseband data and to transmit the northbound time-domain digital baseband data towards the switched Ethernet network and the digital data converter.

[0075] Example 5 includes the system of any of Examples 1-4, wherein the digital data converter (a) is a time domain / frequency domain converter and (b) is configured to be communicatively coupled, through either a fronthaul multiplexer (FHM) communicatively coupled to the switched Ethernet network or the switched Ethernet network comprising the FHM, to the at least one digital baseband data interface radio unit comprising at least two frequency-domain digital baseband data interface (FDI) radio units each of which is configured to receive a same stream of southbound frequency-domain digital baseband data from the FHM which is configured (x) to combine northbound streams of frequency-domain digital baseband data received from each of the at least two FDI radio units into a single stream of northbound frequency-domain digital baseband data and (y) to transmit the single stream of northbound frequency-domain digital baseband data to the time domain / frequency domain converter.

[0076] Example 6 includes the system of any of Examples 1-5, wherein the digital data converter is a time domain / frequency domain converter; wherein the time domain / frequency domain converter is configured to be communicatively coupled, through the switched Ethernet network, to the at least one digital baseband data interface radio unit comprising (a) a first frequency-domain digital baseband data interface (FDI) radio unit communicatively coupled to the switched Ethernet network and (b) a second FDI radio unit that is subtended from the first FDI radio unit and communicatively coupled to the switched Ethernet network through the first FDI radio unit which transmits southbound frequency-domain digital baseband data, received by the first FDI radio unit, to the second FDI radio unit and combines northbound frequency-domain digital baseband data of the first FDI radio unit with northbound frequency-domain digital baseband data received from the second FDI radio unit and transmits combined northbound frequency-domain digital baseband data to the time domain / frequency domain converter.

[0077] Example 7 includes the system of any of Examples 1-6, further comprising: the switched Ethernet network; and the at least one digital baseband data interface radio unit each of which is electrically connected to a set of one or more antennas each of which is configured to radiate another analog RF signal derived from the digital data and transmitted from one of the at least one digital baseband data interface radio unit.

[0078] Example 8 includes the system of any of Examples 1-7, wherein the southbound time-domain digital baseband data is southbound time-domain digital baseband in-phase and quadrature phase (IQ) data, the southbound digital baseband data of the other digital format is southbound digital baseband IQ data of the other digital format, the northbound time-domain digital baseband data is northbound timedomain digital baseband IQ data, and the northbound digital baseband data of the other digital format is northbound digital baseband IQ data of the other digital format. [0079] Example 9 includes a method for communicating southbound data in a radio access network (RAN), the method comprising: receiving a southbound analog radio frequency (RF) signal from an RF-interface base station; converting the southbound analog RF signal to southbound time-domain digital baseband data; converting the southbound time-domain digital baseband data to southbound digital baseband data in another digital format; and transmitting the southbound digital baseband data in the other digital format through a switched Ethernet network to at least one digital baseband interface radio unit.

[0080] Example 10 includes the method of Example 9, wherein transmitting the southbound digital baseband data in the other digital format through the switched Ethernet network to the at least one digital baseband interface radio unit comprises transmitting the southbound digital baseband data in the other digital format through the switched Ethernet network of an open radio access network and to the at least one digital baseband interface radio unit each of which is an open radio access network radio unit.

[0081] Example 11 includes the method of any of Examples 9-10, wherein converting the southbound time-domain digital baseband data to the southbound digital baseband data in the other digital format comprises converting the southbound time-domain digital baseband data to southbound frequency-domain digital baseband data; wherein transmitting the southbound digital baseband data in the other digital format through the switched Ethernet network to the at least one digital baseband interface radio unit comprises transmitting the southbound frequency-domain digital baseband data through the switched Ethernet network to the at least one digital baseband interface radio unit each of which is a frequency-domain digital baseband data interface (FDI) radio unit.

[0082] Example 12 includes the method of any of Examples 9-11, wherein converting the southbound time-domain digital baseband data to the southbound digital baseband data in the other digital format comprises encapsulating the southbound time-domain digital baseband data into southbound enhanced common public radio interface (eCPRI) frames; wherein transmitting the southbound digital baseband data in the other digital format through the switched Ethernet network to the at least one digital baseband interface radio unit comprises transmitting the southbound time-domain digital baseband data encapsulated in southbound eCPRI frames through the switched Ethernet network, decapsulating the southbound timedomain digital baseband data from the southbound eCPRI frames, and transmitting decapsulated southbound time-domain digital baseband data to the at least one digital baseband interface radio unit each of which is a time-domain digital baseband data interface (TDI) radio unit.

[0083] Example 13 includes the method of any of Examples 9-12, wherein converting the southbound time-domain digital baseband data to the southbound digital baseband data in the other digital format comprises converting the southbound time-domain digital baseband data to southbound frequency-domain digital baseband data; wherein transmitting the southbound digital baseband data in the other digital format through the switched Ethernet network to the at least one digital baseband interface radio unit comprises transmitting the southbound frequency-domain digital baseband data, through either a fronthaul multiplexer (FHM) communicatively coupled to the switched Ethernet network or the switched Ethernet network comprising the FHM, to the at least one digital baseband interface radio unit comprising at least two frequency-domain digital baseband data interface (FDI) radio units each of which is configured to receive a same stream of southbound frequencydomain digital baseband data from the FHM.

[0084] Example 14 includes the method of any of Examples 9-13, wherein converting the southbound time-domain digital baseband data to the southbound digital baseband data in other digital format comprises converting the southbound time-domain digital baseband data to southbound frequency-domain digital baseband data; wherein transmitting the southbound digital baseband data in the other digital format through the switched Ethernet network to the at least one digital baseband interface radio unit comprises transmitting southbound frequency-domain digital baseband data through the switched Ethernet network to the at least frequency-domain digital baseband data interface (FDI) radio unit comprising a first FDI radio unit communicatively coupled to the switched Ethernet network and a second FDI radio unit that is subtended from the first FDI radio unit and communicatively coupled to the switched Ethernet network through the first FDI radio unit which transmits the southbound frequency-domain digital baseband data, received by the first FDI radio unit, to the second FDI radio unit. [0085] Example 15 includes the method of any of Examples 9-14, wherein the southbound time-domain digital baseband data is southbound time-domain digital baseband in-phase and quadrature phase (IQ) data, and the southbound digital baseband data of the other digital format is southbound digital baseband IQ data of another digital format.

[0086] Example 16 includes a method for communicating northbound data in a radio access network (RAN), the method comprising: receiving northbound digital baseband data in a digital format through a switched Ethernet network from at least one digital baseband interface radio unit; converting the northbound digital baseband data in the digital format to northbound time-domain digital baseband data; converting the northbound time-domain digital baseband data to a northbound analog RF signal; and transmitting the northbound analog RF signal to an RF-interface base station.

[0087] Example 17 includes the method of Example 16, wherein receiving the northbound digital baseband data in the digital format through the switched Ethernet network from the at least one digital baseband interface radio unit comprises receiving the northbound digital baseband data in the digital format through the switched Ethernet network of an open radio access network and from the at least one digital baseband interface radio unit each of which is an open radio access network radio unit.

[0088] Example 18 includes the method of any of Examples 16-17, wherein receiving the northbound digital baseband data in the digital format through the switched Ethernet network from the at least one digital baseband interface radio unit comprises receiving northbound frequency-domain digital baseband data through the switched Ethernet network from the at least one digital baseband interface radio unit each of which is a frequency-domain digital data interface (FDI) radio unit; wherein converting the northbound digital baseband data in the digital format to the northbound time-domain digital baseband data comprises converting the northbound frequency-domain digital baseband data to northbound time-domain digital baseband data.

[0089] Example 19 includes the method of any of Examples 16-18, wherein receiving the northbound digital baseband data in the digital format through the switched Ethernet network from the at least one digital baseband interface radio unit comprises receiving northbound enhanced common public radio interface (eCPRI) frames which encapsulate northbound time-domain digital data from the at least one digital baseband interface radio unit each of which is a time-domain digital baseband interface (TDI) radio unit; wherein converting the northbound digital baseband data in the digital format to northbound time-domain digital baseband data comprises extracting the northbound time-domain baseband data from the northbound eCPRI frames.

[0090] Example 20 includes the method of any of Examples 16-19, wherein receiving the northbound digital baseband data in a digital format through the switched Ethernet network from the at least one digital baseband interface radio unit comprises receiving the northbound frequency-domain digital baseband data, through either a fronthaul multiplexer (FHM) communicatively coupled to the switched Ethernet network or the switched Ethernet network comprising the FHM, configured to combine streams of northbound frequency-domain digital baseband data received from each at least two frequency-domain digital baseband data interface (FDI) radio units; and wherein converting the northbound digital baseband data in the digital format to the northbound time-domain digital baseband data comprises converting the northbound frequency-domain digital baseband data to northbound time-domain digital baseband data.

[0091] Example 21 includes the method of any of Examples 16-20, wherein receiving the northbound digital baseband data in a digital format through the switched Ethernet network from the at least one digital baseband interface radio unit comprises receiving the northbound frequency-domain digital baseband data from a first frequency-domain digital baseband data interface (FDI) radio unit communicatively coupled to the switched Ethernet network and configured to receive a stream of northbound frequency-domain digital baseband data from a second FDI radio unit that is subtended from the first FDI radio unit and configured to combine streams of northbound frequency-domain digital baseband data from each the first and the second FDI radio units.

[0092] Example 22 includes the method of any of Examples 16-21, the northbound time-domain digital baseband data is northbound time-domain digital baseband IQ data, and the northbound digital baseband data of the other digital format is northbound digital baseband IQ data of the other digital format.

Claims

CLAIMS What is claimed is:

1. A system configured to communicatively couple an RF -interface base station with at least one digital baseband data interface radio unit, the system comprising: an analog RF signal / digital data converter configured (a) to convert a southbound analog RF signal received from the RF-interface base station, to southbound time-domain digital baseband data and (b) to convert northbound timedomain digital baseband data to a northbound analog RF signal and to transmit the northbound analog RF signal to the RF-interface base station; and a digital data converter configured (a) to convert southbound time-domain digital baseband data, received from the analog RF signal / digital data converter, to southbound digital baseband data of another digital format, (b) to convert northbound digital baseband data of the other digital format to the northbound time-domain digital baseband data, and (c) to be communicatively coupled, through a switched Ethernet network, to the at least one digital baseband data interface radio unit each of which is configured to receive the southbound digital baseband data of the other digital format from the digital data converter and to transmit to the digital data converter the northbound digital baseband data of the other digital format.

2. The system of claim 1, wherein the digital data converter is configured to be communicatively coupled, through the switched Ethernet network, to the at least one digital baseband data interface radio unit comprises the digital data converter is configured to be communicatively coupled, through the switched Ethernet network of an open radio access network, to the at least one digital baseband data interface radio unit each of which is an open radio access network radio unit.

3. The system of claim 1, wherein the digital data converter is configured to be communicatively coupled, through the switched Ethernet network, to the at least one digital baseband data interface radio unit each of which is a frequency-domain digital baseband data interface (FDI) radio unit configured to receive southbound frequencydomain digital baseband data and to transmit northbound frequency-domain digital baseband data through the switched Ethernet network to the digital data converter; wherein the digital data converter is a time domain / frequency domain converter and digital baseband data in the other digital format is time-domain digital baseband data.

4. The system of claim 1, wherein the digital data converter is a first timedomain digital data encapuslator / decapsulator converter configured to encapsulate the southbound time-domain digital baseband data, from the analog RF signal / digital data converter, into southbound enhanced common public radio interface (eCPRI) frames and to extract the northbound time-domain digital baseband data from northbound eCPRI frames provided to the analog RF signal / digital data converter; and wherein the other digital format is eCPRI frames; wherein the digital data converter is configured to be communicatively coupled, through the switched Ethernet network, to the at least one digital baseband data interface radio unit each of which is a time-domain digital baseband data interface (TDI) radio unit configured to receive decapsulated southbound timedomain digital baseband data and to transmit the northbound time-domain digital baseband data towards the switched Ethernet network and the digital data converter.

5. The system of claim 1, wherein the digital data converter (a) is a time domain / frequency domain converter and (b) is configured to be communicatively coupled, through either a fronthaul multiplexer (FHM) communicatively coupled to the switched Ethernet network or the switched Ethernet network comprising the FHM, to the at least one digital baseband data interface radio unit comprising at least two frequency-domain digital baseband data interface (FDI) radio units each of which is configured to receive a same stream of southbound frequency-domain digital baseband data from the FHM which is configured (x) to combine northbound streams of frequency-domain digital baseband data received from each of the at least two FDI radio units into a single stream of northbound frequency-domain digital baseband data and (y) to transmit the single stream of northbound frequency-domain digital baseband data to the time domain / frequency domain converter.

6. The system of claim 1, wherein the digital data converter is a time domain / frequency domain converter; wherein the time domain / frequency domain converter is configured to be communicatively coupled, through the switched Ethernet network, to the at least one digital baseband data interface radio unit comprising (a) a first frequency-domain digital baseband data interface (FDI) radio unit communicatively coupled to the switched Ethernet network and (b) a second FDI radio unit that is subtended from the first FDI radio unit and communicatively coupled to the switched Ethernet network through the first FDI radio unit which transmits southbound frequency-domain digital baseband data, received by the first FDI radio unit, to the second FDI radio unit and combines northbound frequency-domain digital baseband data of the first FDI radio unit with northbound frequency-domain digital baseband data received from the second FDI radio unit and transmits combined northbound frequency-domain digital baseband data to the time domain / frequency domain converter.

7. The system of claim 1, further comprising: the switched Ethernet network; and the at least one digital baseband data interface radio unit each of which is electrically connected to a set of one or more antennas each of which is configured to radiate another analog RF signal derived from the digital data and transmitted from one of the at least one digital baseband data interface radio unit.

8. The system of claim 1, wherein the southbound time-domain digital baseband data is southbound time-domain digital baseband in-phase and quadrature phase (IQ) data, the southbound digital baseband data of the other digital format is southbound digital baseband IQ data of the other digital format, the northbound time-domain digital baseband data is northbound time-domain digital baseband IQ data, and the northbound digital baseband data of the other digital format is northbound digital baseband IQ data of the other digital format.

9. A method for communicating southbound data in a radio access network (RAN), the method comprising: receiving a southbound analog radio frequency (RF) signal from an RF- interface base station; converting the southbound analog RF signal to southbound time-domain digital baseband data; converting the southbound time-domain digital baseband data to southbound digital baseband data in another digital format; and transmitting the southbound digital baseband data in the other digital format through a switched Ethernet network to at least one digital baseband interface radio unit.

10. The method of claim 9, wherein transmitting the southbound digital baseband data in the other digital format through the switched Ethernet network to the at least one digital baseband interface radio unit comprises transmitting the southbound digital baseband data in the other digital format through the switched Ethernet network of an open radio access network and to the at least one digital baseband interface radio unit each of which is an open radio access network radio unit.

11. The method of claim 9, wherein converting the southbound time-domain digital baseband data to the southbound digital baseband data in the other digital format comprises converting the southbound time-domain digital baseband data to southbound frequency-domain digital baseband data; wherein transmitting the southbound digital baseband data in the other digital format through the switched Ethernet network to the at least one digital baseband interface radio unit comprises transmitting the southbound frequency-domain digital baseband data through the switched Ethernet network to the at least one digital baseband interface radio unit each of which is a frequency-domain digital baseband data interface (FDI) radio unit.

12. The method of claim 9, wherein converting the southbound time-domain digital baseband data to the southbound digital baseband data in the other digital format comprises encapsulating the southbound time-domain digital baseband data into southbound enhanced common public radio interface (eCPRI) frames; wherein transmitting the southbound digital baseband data in the other digital format through the switched Ethernet network to the at least one digital baseband interface radio unit comprises transmitting the southbound time-domain digital baseband data encapsulated in southbound eCPRI frames through the switched Ethernet network, decapsulating the southbound time-domain digital baseband data from the southbound eCPRI frames, and transmitting decapsulated southbound timedomain digital baseband data to the at least one digital baseband interface radio unit each of which is a time-domain digital baseband data interface (TDI) radio unit.

13. The method of claim 9, wherein converting the southbound time-domain digital baseband data to the southbound digital baseband data in the other digital format comprises converting the southbound time-domain digital baseband data to southbound frequency-domain digital baseband data; wherein transmitting the southbound digital baseband data in the other digital format through the switched Ethernet network to the at least one digital baseband interface radio unit comprises transmitting the southbound frequency-domain digital baseband data, through either a fronthaul multiplexer (FHM) communicatively coupled to the switched Ethernet network or the switched Ethernet network comprising the FHM, to the at least one digital baseband interface radio unit comprising at least two frequency-domain digital baseband data interface (FDI) radio units each of which is configured to receive a same stream of southbound frequencydomain digital baseband data from the FHM.

14. The method of claim 9, wherein converting the southbound time-domain digital baseband data to the southbound digital baseband data in other digital format comprises converting the southbound time-domain digital baseband data to southbound frequency-domain digital baseband data; wherein transmitting the southbound digital baseband data in the other digital format through the switched Ethernet network to the at least one digital baseband interface radio unit comprises transmitting southbound frequency-domain digital baseband data through the switched Ethernet network to the at least frequency-domain digital baseband data interface (FDI) radio unit comprising a first FDI radio unit communicatively coupled to the switched Ethernet network and a second FDI radio unit that is subtended from the first FDI radio unit and communicatively coupled to the switched Ethernet network through the first FDI radio unit which transmits the southbound frequency-domain digital baseband data, received by the first FDI radio unit, to the second FDI radio unit.

15. The method of claim 9, wherein the southbound time-domain digital baseband data is southbound time-domain digital baseband in-phase and quadrature phase (IQ) data, and the southbound digital baseband data of the other digital format is southbound digital baseband IQ data of another digital format.

16. A method for communicating northbound data in a radio access network (RAN), the method comprising: receiving northbound digital baseband data in a digital format through a switched Ethernet network from at least one digital baseband interface radio unit; converting the northbound digital baseband data in the digital format to northbound time-domain digital baseband data; converting the northbound time-domain digital baseband data to a northbound analog RF signal; and transmitting the northbound analog RF signal to an RF-interface base station.

17. The method of claim 16, wherein receiving the northbound digital baseband data in the digital format through the switched Ethernet network from the at least one digital baseband interface radio unit comprises receiving the northbound digital baseband data in the digital format through the switched Ethernet network of an open radio access network and from the at least one digital baseband interface radio unit each of which is an open radio access network radio unit.

18. The method of claim 16, wherein receiving the northbound digital baseband data in the digital format through the switched Ethernet network from the at least one digital baseband interface radio unit comprises receiving northbound frequencydomain digital baseband data through the switched Ethernet network from the at least one digital baseband interface radio unit each of which is a frequency-domain digital data interface (FDI) radio unit; wherein converting the northbound digital baseband data in the digital format to the northbound time-domain digital baseband data comprises converting the northbound frequency-domain digital baseband data to northbound time-domain digital baseband data.

19. The method of claim 16, wherein receiving the northbound digital baseband data in the digital format through the switched Ethernet network from the at least one digital baseband interface radio unit comprises receiving northbound enhanced common public radio interface (eCPRI) frames which encapsulate northbound timedomain digital data from the at least one digital baseband interface radio unit each of which is a time-domain digital baseband interface (TDI) radio unit; wherein converting the northbound digital baseband data in the digital format to northbound time-domain digital baseband data comprises extracting the northbound time-domain baseband data from the northbound eCPRI frames.

20. The method of claim 16, wherein receiving the northbound digital baseband data in a digital format through the switched Ethernet network from the at least one digital baseband interface radio unit comprises receiving the northbound frequencydomain digital baseband data, through either a fronthaul multiplexer (FHM) communicatively coupled to the switched Ethernet network or the switched Ethernet network comprising the FHM, configured to combine streams of northbound frequency-domain digital baseband data received from each at least two frequencydomain digital baseband data interface (FDI) radio units; and wherein converting the northbound digital baseband data in the digital format to the northbound time-domain digital baseband data comprises converting the northbound frequency-domain digital baseband data to northbound time-domain digital baseband data.

21. The method of claim 16, wherein receiving the northbound digital baseband data in a digital format through the switched Ethernet network from the at least one digital baseband interface radio unit comprises receiving the northbound frequencydomain digital baseband data from a first frequency-domain digital baseband data interface (FDI) radio unit communicatively coupled to the switched Ethernet network and configured to receive a stream of northbound frequency-domain digital baseband data from a second FDI radio unit that is subtended from the first FDI radio unit and configured to combine streams of northbound frequency-domain digital baseband data from each the first and the second FDI radio units.

22. The method of claim 16, the northbound time-domain digital baseband data is northbound time-domain digital baseband IQ data, and the northbound digital baseband data of the other digital format is northbound digital baseband IQ data of the other digital format.