Contents1 Introduction11.1 Functions of the BBU390011.2 Appearance of the BBU390011.3 Boards of the BBU390022 Technical Specifications72.1 BBU3900 Capacity72.2 BBU3900 Transmission Ports72.3 Input Power82.4 Equipment Specifications82.5 Environment Specifications93 Acronyms and Abbreviations11

IntroductionFunctions of the BBU3900The BBU3900 is a baseband control unit. It performs the following functions:Performing signal interaction between the base station and the BSC or RNCProviding the system clockManaging the entire base station in terms of OM and signaling processingProviding an OM channel for the connection to the LMT or M2000Two BBU3900 cabinets can be stacked to expand the capacity.Appearance of the BBU3900The BBU3900 has a case structure. It can be installed in a 19-inch-wide and 2 U-high indoor spaces or outdoor protective cabinet. Outdoor solution is applicable to outdoor scenarios such as basement, balcony, corridor, and garage. Indoor solution is applicable to indoor scenarios such as office and house. Figure 1-1 shows the BBU3900.BBU3900

Boards of the BBU3900The BBU3900 can be configured with the following boards: GSM Timing and Main control Unit (GTMU) WCDMA Main Processing Transmission unit (WMPT) LTE Main Processing Transmission unit (LMPT) WCDMA Baseband Processing unit (WBBP) LTE BaseBand Processing unit (LBBP) Universal Transmission Processing unit (UTRP) Universal Power and Environment Interface Unit (UPEU) Universal Environment Interface Unit (UEIU) Universal Satellite card and Clock Unit (USCU) Universal Baseband Radio Interference board (UBRI) FAN moduleThese boards support plug-and-play, and thus can be configured as required. Table 1-1 lists the functions of BBU3900 boards.Functions of the BBU3900 boardsBoardFunction

GTMUPerforms OM functions such as configuration management, equipment management, performance monitoring, signaling processing, and radio resource managementProvides an OM channel for the connection to the OMC (LMT or M2000)Provides a reference clock for the entire system Provides four E1s, one FE electrical port, and one FE optical port Provides six CPRI ports for the communication with RF modules

WMPTPerforms OM functions such as configuration management, equipment management, performance monitoring, signaling processing, radio resources management, and active/standby switchoverProvides an OM channel for connection to the OMC (LMT or M2000) Provides a reference clock for the entire system Provides four E1s that support both ATM transport and IP transport Provides one FE electrical port and one FE optical port. Both of them support the IP transport.

LMPTPerforms OM functions such as configuration management, equipment management, performance monitoring, signaling processing, and radio resources managementProvides an OM channel for the connection to the OMC (LMT or M2000) Provides a reference clock for the entire systemProvides Ethernet optical ports for the connection to transmission devices or gateway devices

WBBPWBBPb: providing three CPRI ports for the communication with RF modulesWBBPd: providing six CPRI ports for the communication with RF modulesProcesses uplink and downlink baseband signals

LBBPProvides six CPRI ports for the communication with RF modulesProcesses uplink and downlink baseband signals

UTRPUTRP2: providing two FE/GE optical ports for Ethernet MAC layer functions including sending and receiving Ethernet link data and MAC address resolutionUTRP3: providing eight routes of ATM over E1s/T1s on which an ATM data flow is inversely multiplexed and demultiplexedUTRP4: providing eight routes of IP over E1s/T1s on which HDLC frames are decapsulated and assembled, assignment and controlling 256 HDLC timeslotsUTRPb4: providing four TDM E1s/T1s for the GSM mode, and providing another four TDM E1s/T1s for transmission extension of another mode during dual-mode transmissionUTRP6: providing one unchannelized STM-1/OC-3 portUTRP9: providing four FE/GE electrical ports for the MAC layer and physical layer functions of the Ethernet

UPEUConverts the -48 V DC or +24 V DC power input to the +12 V power input Provides two ports with each transmitting one route of RS485 signals and another two ports with each transmitting four routes of Boolean signals.

UEIUProvides two ports with each transmitting one route of RS485 signals and another two ports with each transmitting four routes of Boolean signalsTransmits the information reported by the environment monitoring unit and alarm information to the main control board

USCUProvides the input port for the external RGPS (such as reused devices), BITS device, and TOD USCUb1: providing a GPS-capable satellite card for time synchronization or obtaining clock signals from transmission links USCUb2: providing a dual-satellite card that supports both GPS and GLONASS

UBRIProvides six CPRI ports for the communication with RF modules

BBU3900 Board Configuration in Single ModeFigure 1-2, Figure 1-3, and Figure 1-4 show the typical board configurations of the BBU3900 working in GSM mode, UMTS mode, and LTE mode respectively.Typical board configuration of the BBU3900 in GSM mode

Typical board configuration of the BBU3900 in UMTS mode

Typical board configuration of the BBU3900 in LTE mode

BBU3900 Board Configuration in Dual ModeFigure 1-5, Figure 1-6, and Figure 1-7 show the typical board configurations of the BBU3900 working in GSM+UMTS dual mode, GSM+LTE dual mode, and UMTS+LTE dual mode respectively.Typical board configuration of the BBU3900 in GSM+UMTS dual mode

Typical board configuration of the BBU3900 in GSM+LTE dual mode

Typical board configuration of the BBU3900 in UMTS+LTE dual mode

BBU3900 Board Configuration in Triple ModeFigure 1-8 shows the typical board configurations of the BBU3900 working in GSM+UMTS-LTE triple mode.Typical board configuration of the BBU3900 in GSM+UMTS-LTE triple mode

BBU3900 Description

Technical SpecificationsBBU3900 CapacityBBU3900 capacityModeCapacity

GSMS24/24/24

UMTSS8/8/8 (1,536 CEs in the UL and 1,536 CEs + 15 24 HSDPA codes in the DL)

GSM+UMTSGSM S24/24/24 + UMTS S8/8/8 (1,536 CEs in the UL and 1,536 CEs + 15 24 HSDPA codes in the DL)

LTE42 MIMO: 6 cells(5MHz/10MHz/15 MHz/20MHz)22 MIMO: 12 cells(5MHz/10MHz/15 MHz/20MHz)

BBU3900 Transmission PortsBBU3900 transmission portsModeTransmission Ports

GSMGTMU4 E1s/T1s, 1 FE electrical port, 1 FE optical port

UTRPb48 E1s/T1s (UTRPb4 and GTMU totally support 8 E1s/T1s)

GSM+UMTSWMPT4 E1s/T1s, 1 FE electrical port, 1 FE optical port

GTMU4 E1s/T1s, 1 FE electrical port, 1 FE optical port

UTRP22 FE/GE optical ports

UTRP38 E1s/T1s

UTRP48 E1s/T1s

UTRPb48 E1s/T1s (UTRPb4 and GTMU totally support 8 E1s/T1s)

UTRP61 STM-1/OC-3 port

UTRP94 FE/GE electrical ports

UMTSWMPT4 E1s/T1s, 1 FE electrical port, 1 FE optical port

UTRP22 FE/GE optical ports

UTRP38 E1s/T1s

UTRP48 E1s/T1s

UTRP61 STM-1/OC-3 port

UTRP94 FE/GE electrical ports

LTELMPT2 FE/GE electrical ports 2 FE/GE optical ports1 FE/GE electrical port + 1 FE/GE optical port

Input PowerInput powerItemSpecification

Input power48 V DC; voltage range: 38.4 V DC to 57 V DC

Equipment SpecificationsEquipment specificationsItemSpecification

Dimension (H x W x D )86 mm 442mm 310 mm

WeightBBU3900 12 kg (in full configuration)BBU3900 7 kg (in typical configuration)

Environment SpecificationsEnvironment specificationsItemSpecification

Operating temperature20C to +55C

Relative humidity5% RH to 95% RH

Protection ratingIP20

Signaling StormWith increased application of intelligent terminals on the networks and application of high-end services (such as Push Mail of RIM), networks face increasing signaling load. Potential application services of intelligent terminals may bring additional bursting signaling that may crash networks. The signaling plane handles RM/NBAP messages. In a 3900 NodeB, the WMPT CPU handles CNBAP messages, namely, all Iub singling and resource allocation, including SCTP signaling. The WBBP handles the DNBAP messages.After two or more baseband boards are configured for a 3900 NodeB, the control board becomes the bottleneck for signaling processing capability. Add the UTRP to divide the processing tasks on the transmission control panel of the main control board. This improves the signaling processing capability of the BBU.ConfigurationNBAP RAN12.0NBAP RAN13.0

WBBP+1*WBBP5560

WBBP+2*WBBP110120

WBBP+3*WBBP130170

WBBP+4*WBBP130170

UTRP+WBBP+1*WBBP5560

UTRP+WBBP+2*WBBP110120

UTRP+WBBP+3*WBBP165180

UTRP+WBBP+4*WBBP200240

When multiple baseband boards form an UL resource group, the algorithm automatically adjust the signaling processing load between different boards in the resource group. If baseband boards from multiple resource groups, the algorithm cannot adjust the load between resource groups in versions earlier than RAN13.0 released in September of 2011. The load must be adjusted manually to reach a balance between resource groups. If the load is not adjusted, the processing capability of the entire NodeB cannot meet the specifications because the processing capability of resource groups cannot be fully used. The signaling processing load is automatically adjusted from versions later than RAN13.0.The enhanced feature of quick hibernation (WRFD 020500) is introduced. After the RNC receives the signaling connection release indication (SCRI) of the UE, or the UE inactivity timer times out, change the UE status to the CELL/URA_PCH status (not the IDLE status in the traditional quick hibernation system) to reduce the signaling traffic between the NodeB and RNC.

Acronyms and AbbreviationsAbbreviationFull Name

BBUBaseband Unit

CEChannel Elements

CPRICommon Public Radio Interface

DLDownlink

FEFast Ethernet

GPSGlobal Positioning System

GTMUGSM Timing and Main control Unit

HSDPAHigh Speed Downlink Packet Access

LBBPLTE BaseBand Processing unit

LMPTLTE Main Processing Transmission unit

LMTLocal Maintenance Terminal

LTELong Term Evolution

MIMOMulti-input and Multi-output

OMOperation and Maintenance

RNCRadio Network Controller

STM-1Synchronous Transport Mode-1

UBRIUniversal Baseband Radio Interference board

UCIUUniversal Cascaded Interface Unit

UEIUUniversal Environment Interface Unit

ULUplink

UMTSUniversal Mobile Telecommunications System

UPEUUniversal Power and Environment Interface Unit

USCUUniversal Satellite card and Clock Unit

UTRPUniversal Transmission Processing unit

WBBPWCDMA Baseband Processing unit

WMPTWCDMA Main Processing Transmission unit