01.Introduction to GU SDR BTS

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Introduction to GU SDR Base Stations

GU Product Support Dept.

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23/5/2 2

Purpose

23/5/2 2

You are expected to master the following knowledge after this course

basic concepts and structure of SDR

Types of SDR base stations

SDR hardware boards

Interfaces of SDR base stations

内部公开 Internal Only▲

Contents

Basic Concepts of SDRStructure of SDR Base StationsIntroduction to BBUIntroduction to RU/RRUIntroduction to Interface between BBU and RU/RRUSpecial Functions of SDR Base Stations

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What is SDR (1) The radio technologies defined by the SDR forum are classified

into five levels: HR, SCR, SDR, ISR and USR. HR—— hardware radio Tier0. For example, the traditional

single-mode base station. SCR——software choose radio Feature: Single-mode base transceiver stations of different

modes can be placed together, but they are integrated in terms of software.

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What is SDR (2) SDR- Software Defined Radio: you can use the software to

select a demodulation mode, broadband signals or narrowband signals. ZTE ZDR base station series leads the technologies in the industry.

Feature: Different radio modes can share hardware, including RF front end, ADC/DAC and base band processing.

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What is SDR (3) ISR——Idea software radio. Feature: 1) get rid of the analog RF front end; 2) the whole system can be

controlled by programming except the antenna. USR——Ultimate software radio Feature: 1) it has the function of the ISR; 2) the controlling software should

be standardized. Switch between different radio modes can be finished within milliseconds.

The ISR cannot be widely used because the technology is not mature.

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What is SDR (4) SDR and cognitive radio Cognitive radio is an

important technology of USR. It can perceive the surroundings, and adjust the wireless bandwidth and de-modulation mode accordingly.


Contents

Basic concepts of SDRStructure of SDR Base StationsIntroduction to BBUIntroduction to RU/RRUIntroduction to Interface between BBU and RU/RRUSpecial Functions of SDR Base Stations

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SDR technology brings changes to base station structure

Significant feature of the SDR – software defined radio mode

1 The RF front end processes signals of multiple radio modes

2 Baseband processes signalsof multiple radio modes

3 Software integration to unify software versions

SDR technologySDR technology– – the system supports the system supports multiple radio modesmultiple radio modes

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Market drives changes to the base station structure

Green base station

Cut cost

StructureStructure

A B

Compatible

DWireless integration,IP technology

C

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Structure of ZTE SDR base station Support the distributed structure of BBU and RRU. For

traditional base stations, BBU and RRU should be in the same module.

Multi-mode base band pool BBU Multi-mode RF platform Adopt IP technology to process internal data stream of the base

station OMC platform——OMCR and OMCB Unified software platform

The distributed structure of BBU and RRU and R&D on a unified platform are the core of the SDR base stations. The new structure meets the demand and technology required by the market.

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ANT

Transceiver

Front end of Rx

Duplex

Multi-

carrier PA

External power PWS 220VAC

RRU/RU

BBU

Resource

control board

BBU baseband poolFiber

SDR product structure

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SDR product architecture

Distributed base station: RF is distributed remotely

RRU

BBU

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SDR product architecture

Macro base station: BBU and RU are all in the cabinet, which is different from the distributed base station in structure.

Internal Only▲Advantage 1 of the SDR architecture – BBU and RRU can be distributed separately

In this mode, both BBU and RRU and maximize their efficiency. BBU can achieve the maximum integration, and RRU can focus on the power of itself.

The networking is flexible if the RRU is distributed remotely. For example, it can support multi-carrier and indoor distributed coverage.

BBU and RRU can be distributed flexibly, which benefit for compatibility design.

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Advantage 2 of the SDR architecture – baseband hardware

Support multiple radio modes Simple design Powerful processing capability Easy to manage Easy to share resources Cut cost Easy for evolution of baseband technologies

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Advantage 3 of the SDR architecture – independent RF unit

Simplified functions Improved reliability, easy for maintenance Improved the efficiency of the power amplifier Optimized heat design, easy for integration Closer to antenna, hence bigger power Flexible forms of RU/RRU products Help to reduce the size and weight of base stations Cut cost

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Advantage 4 of the SDR architecture – unified interface between BBU and RU/RRU

The interface between BBU and RU/RRU is the exclusive interface for communication between BBU and RU/RRU .

The interface between BBU and RU/RRU supports such radio modes as GSM, WCDMA, TD-SCDMA, etc.

Support fiber interface and electrical interface Support 1.2288Gbps and 2.4576Gbps rate Support both star-type and link-type networking between BBU

and RU/RRU Support RU/RRU cascading-connection RRU can be distributed remotely. BBU should keep 40 km

away from RRU. GERAN evolvement has been taken into consideration in the

design of the interface between BBU and RU/RRU.

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Distributed base station: B8200 ＋ R8860

B8200: powerful BBU It supports 60 GSM carriers, and support both GSM and

WCDMA. R8860: dual mode RRU, broadband transceiver It supports GSM single-mode 6-carrier, or WCDMA single-mode

3-sector, or supports both radio modes at the same time.

ZXSDR BBUZXSDR BBU ZXSDR RRU

RF

MSMS

UmUm interfaceinterface

CPRICPRI

FiberFiber

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Indoor dual-mode macro base station – ZXSDR BS8800 Size: main cabinet 950×600×450 mm

extension cabinet 700×600×450 mm Weight: main cabinet ≤ 150Kg

extension cabinet ≤ 130Kg Power: S12/12/12: 1335W

S6/6/6: 825W Input voltage: -48VDC (-40~ -57VDC) Transmission mode: the Abis interface supports 8 E1/T1 links

and 1 GE port. Maximum site configuration: S12/12/12 or O36

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The structure of ZXSDR BS8800

Main cabinet

1650m1650mmm

450 mm450 mm

600mm600mm

PDMCabling trough

Baseband

950m950mmm

PDM

Cabling trough

RF unit

Extension cabinet Fan

RU unit

Heat discharge unit

Ventilation hole

Heat discharge unitVentilation hole

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BBU: baseband unit, which is the same with B8200.

It can contain at most 2 sets of BBU.

RU02: GSM single-mode RF unit

It supports 2 GSM carriers. The BS8800 cabinet can contain 6 RU02

modules. The transmitting power is 20W/40W.

RU60: GU dual mode RF unit. The core part is the same with that of

R8860. It supports 6 GSM carriers or 3 UMTS cells or GU dual-mode

configuration. Cabinet-top transmitting power is 60W.

RU80: GU dual mode RU unit. It is an upgraded version based on

RU60. Cabinet-top transmitting power is 80W.

Indoor dual mode macro base station – ZXSDR BS8800

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BS8800 is developed on ZTE’s unified platform. The rack

includes the physical cabinet, PDM unit and FAN unit.

BBU and the RU modules all adopt － 48V DC power supply.

All of the RU modules have the same size and outline.

The fan rotation speed can be adjusted by the software

according to different heat discharge requirements for

different RU modules, thus to lower down noises and achieve

energy efficient.

BS8800 has been used in the products of the three radio

modes, such as GSM, CDMA and UMTS.

Indoor dual mode macro base station – ZXSDR BS8800

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Size: 1700×600×600 mm

Weight: ≤ 263Kg

Power: S12/12/12: 1886W

S6/6/6: 1261W

Input voltage: -48VDC (-40~ -57VDC)

Transmission mode: the Abis interface supports 8 E1/T1 links

and 1 GE port.

Maximum site configuration: S12/12/12 or O36

Outdoor dual mode macro base station –ZXSDR BS8900

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Baseband/power cabinet

Power cabinet

Horizontal RF cabinet

Vertical RF cabinet

Different sub-cabinets can compose BS8900 of different forms

Except the vertical RF cabinet, the other sub-cabinets have the same size.

Used to put BBU and power module 6U or 12U reserved space

Can contain 300AH battery

Can contain 6 RU modules, or 3 RU modules+150AH battery Nature heat discharge

3 RU modules 150AH battery Nature heat discharge

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Software architecture of the SDR base station – OMC software

OMCB OMCR

BSCRNC

SDR

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Software architecture of the SDR base station – OMC software 2

OMCB is an operation and maintenance unit to manage NodeB in

3GPP. ZTE’s SDR base stations support both radio modes of GSM

and WCDMA. Connection mode of the traditional base station: OMCR-

>BSC->BTS; Connection mode of the SDR: OMCB->BTS, OMCR-

>BSC->BTS.

According to the management mode of WCDMA, the board

management, configuration, software downloading and alarms are all

managed by OMCB. In case of the dual-mode, operation and

maintenance tasks of GSM are moved to OMCB, and OMCR manages

GSM related radio configuration and status management.

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OMCR connects to BTS through BSC, regardless the link status

between BSC and BTS. OMCR sends data to BSC, who then

synchronizes the data to BTS.

OMCB is different from OMCR. OMCB interacts with SDR through IP

links. The interaction between OMCB and SDR may pass or not pass

through BSC/RNC. OMCB and SDR confirm data transmission only, and

BSC/RNC needs not to make confirmation. Physically, OMCB can

interact with SDR through IP routes provided by BSC/RNC.

For dual-mode sites, some OMCB connects with BSC, and some OMCB

connects with RNC. BSC/RNC then connects with SDR through IP

transmission.

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OMCB and OMCR can share the same server or board, but they are two different programs and there is no direct interaction between them. Hence, it is necessary to guarantee data consistent manually. Theoretically, the basic board information is configured on OMCB, and the logic information is configured on OMCR. If data are inconsistent between them, we will take the data on OMCB as the reference data.

The main control board of the SDR will keep a copy of all configuration data of the OMCB. Hence, the data takes effect directly when the SDR starts, without direct interaction between the SDR and OMCB. Then, the SDR creates a link to BSC and requests for radio parameters, and BSC sends the data except configuration information of OMCB to the SDR. Thus, a complete data configuration table is generated. That is a theoretic process. In practice, it is necessary to modify the data configuration. For example, modify radio parameters for expansion projects. Data configuration of OMCB should be compatible with that of OMCR, otherwise, the SDR cannot respond correctly.

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Introduction to the control panel of the SDR platform Abis interface: connect to iBSC by FE or E1 FE: direct transmission by IP directly. The protocol stack is shown in

the below figure on the left. E1: transmission by IP Over E1. The protocol stack is shown in the

below figure on the right.

SCTP

IP

ETH

SCTP

IP

PPP

HDLCMAC

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Media plane of the SDR

The media plane supports transmission by the RTP protocol The UBPG of SDR and the BIPB of iBSC process RTP data of the

user plane. CC is responsible for forwarding messages inside the BBU and over

the Abis interface.

CC

UBPGRRU FS iBSC

Forwarding

RTP


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Unified hardware platform – UTCA uTCA (Micro Telecommunications Computing Architecture ) is a

simplified version (Micro TCA) of ATCA (Advanced Telecommunications Computing Architecture). ATCA and MicroTCA provide various components of different interfaces, different protocols and different performances for switching. It is a standard and open structure.

ATCA mainly orients to the environment requiring high-capacity and high-performance, while uTCA orients to the environment requiring low-capacity and low-performance. uTCA is cost effective and volume sensitive. uTCA inherits many features of ATCA, including basic interconnection topology and management structure.

PCI Industrial Computer Manufactures Group (PICMG for short), is an organization which has over 800 member companies, including Intel, Motorola, and ZTE.

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Hardware – structure

Cabinet - 19 inch - 2U Flexible installation mode - Mounted on the wall

independently - 19 inch standard cabinet - Installed in the Hub cabinet - Installed in the outdoor

cabinet

154 8

163 7

14 2 6

13 1 5

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Hardware – boards Control and clock module (CC) Fabric switching module (FS)(3 or 4 slot) Site alarm module (SA)(13th slot) Baseband processing board (BPC/UBPG)(umts/gsm)(3 or 4) Fan array module (FA)(controled by CC) Power module (PM)(1+1) Backplane board (BB)(CC make managements through BB)

PW FS BP

PW FS BP

SACC BP

CC BP

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Hardware – interfaces E1: supports 16 E1/T1 links at most GE: there are two GE interfaces. One is photo-electric

exclusively, and the other is electric. CPRI: One FS has 6 CPRI interfaces. There are two FS

at most, hence there are 12 CRPI interfaces at most. GPS ： 1

CPRI

GE E1 GE

GPS

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Hardware function module – CC Integrate such functions as main control, clock, switching and the

Iub/Abis interface Physically, the CC does not provide the E1/T1 interface. It connects

E1/T1 to the SA through the backplane of BBU, and the SA provides the E1/T1 interface.

Support the master/slave mode Full IP transmission CC0: It supports internal or external GPS, clock cascaded connection,

and 16 E1 links. It does not support 2MBits clock. CC2: It does not support internal or external GPS and clock cascaded

connection. It supports 2MBits clock and 8 E1 links.

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Hardware function module – FS It supports the master/slave mode and the load sharing function. The slot for FS is also compatible for the baseband board. 6 1.25G CPRI optical ports, which support 24TRX (GSM) or

4CS (WCDMA) each. It does not support master/slave switchover. For GU dual mode N+6×M<=24 (N represents number of TRXs,

and M represents number of CSs)

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Diagram of FS IQ switching

FS

UBPG2

Channel 2

Channel 1

RU1, channel 1

RU1, channel 4

RU1, channel 5

RU1, channel 3

RU1, channel 2

RU1, channel 6

UBPG1

RU1, channel 1

RU1, channel 4

RU1, channel 3

RU1, channel 2

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Hardware function module – SA/SE Environment monitoring module Fan monitor SA: support 8 channels of E1/T1 signals, 1 RS232 serial port or

1 RS485 interface, 6 input dry contact alarm, and 2 double-directional dry contact alarm

SE: support 8 channels of E1/T1 signals, 1 RS232 serial port or 1 RS485 interface, 6 input dry contact alarm, and 2 double-directional dry contact alarm

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Hardware function module – UBPG GSM baseband processing module Responsible for baseband modulation. Downlink: processing up

to 12 carriers, speed adaption, channel coding and interleaving, encryption; producing TDMA burst pulse, GMSK/8PSK modulation; outputting IQ baseband digital signals; sending power and frequency control information to RRU for processing.

Responsible for baseband modulation. Uplink: process up to 12 carriers; after receiving IQ baseband data from RRU, perform diversity combination for the receiver, digital demodulation (GMSK and 8PSK demodulation, balance), decryption, de-interleaving, channel decoding and speed adaption, and then sends to the CC board through the Ethernet port.

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Hardware function module – FA Fan monitoring module Power supply, rotation control and status report LEDs on the fan subrack

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Hardware function module – PM A single PM provides 16 12V-power supply, which can meet the

power supply requirement of B8200 in full configuration. Two PMs working in master/slave mode

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Hardware function module – backplane

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BBU configuration rules

Board ConfigurationsPower module (PM) 1 PM is configured by default. Decide whether it is necessary to

configure 2 PMs according to the requirement for reliability and cost.

Site alarm module (SA) 1 SA is configured by default.

Control and clock module (CC) 1 CC is configured by default. Select either CC0 or CC2 according to the clock and E1. Decide whether it is necessary to configure 2 CCs according to the requirement for reliability and cost.

Fabric switch module (FS) Generally, 1 FS is configured, and 2 FSs at most. The quantity depends on site configuration.

Universal baseband processing board for GSM (UBPG)

The quantity depends on site configuration. The slots are compatible for both the BPC and the UBPG.

Baseband processing board type C (BPC)

The quantity depends on site configuration.The slots are compatible for both the BPC and the UBPG.

Fan array module (FA) 1 FA only is configured

Site alarm extension board (SE)

Optional, which depends on the quantity of dry contacts. It is inserted at Slot 5.


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Multi-carrier RU/RRU (1) The multi-carrier RF modules include three types:

RU60 (60W) , R8860 (60W), and RU80 (80W). RU/RRU uses multi-carrier technology. IT performs

signal synthesis for multiple carriers. It uses only one set of boards and PA, and one set of antenna system. RU60 supports signal synthesis for 6 carriers.

The RU/RRU module has only two external antenna ports. It supports single-transmitting and double receiving generally. If the cell has over 6 carriers, one port should be reserved to connect the other RU.

RU/RRU adopts broadband transceiver and broadband power amplifier.

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Multi-carrier RU/RRU (2)

RU/RRU is responsible for functions of the baseband RF interface and the Uu/Um interface.

RU/RRU is responsible for access and radio link transmission of UE/MS through the Uu/Um interface, including RF processing, modulation/demodulation, measurement and report, power control, receiving diversity, correction, synchronization, etc.

It connects to BBU through the optical interface by the CPRI protocol. It implements the following functions through the optical interface, such as IQ data transmission, measurement report, RF function configuration, clock synchronization, etc.

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R8840: 2100M UMTS single mode, cabinet-top transmitting

power: 60w, supporting 4CS (actually, 3CSs are configured to

meet the requirement of 20w/CS.)

R8860: support 850M/900MGU dual-mode or 1800M/1900M

single mode. Cabinet top: 80w (GMSK), supporting 24TRX or

4CS or 2W+2G or 1W+4G

R8880: 2100M UMTS single mode; cabinet-top output power:

2×60w, supporting MIMO (2T2R) and 4CS

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R8840: support -48VDC, 110VAC, 220VAC

R8860: support -48VDC. It does not support AC power supply

R8880: support -48VDC, 110VAC, 220VAC

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RU/RRU configuration rules RRU supports at most 4-level cascaded connection. In practice,

however, it is suggested to adopt only 2-level cascaded connection in networking.

For RRUs in cascaded connection, there is no limit to the position, sequence, frequency band, and radio mode.

RRUs of different bands share neither antennas nor feeders. If a backbone physical site (iron tower) is installed with over 3 sets of

RRU, it is necessary to configure 1 BBU nearby the iron tower. If a backbone physical site (iron tower) is installed with both R8840

and R8860, it is necessary to configure 1 BBU nearby the iron tower. If the physical site for hole coverage is configured with 1 – 2 sets of

RRU, it is suggested to connect the fiber from the nearest backbone BBU, instead of from tower-top backbone RRU.

For multiple sets of RRUs sharing the iron tower, the isolation between TX/Rx and RX must greater than 30dB.

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RSU60E and R8860E

RSU60E / R8860E uses the ADTR instead of the previous DTR.

Compared with RSU60 (80W) /R8860 (80W), they have the same

cabinet-top output power, but the working bandwidth and RF

indices are greatly improved. The bandwidth of a single module

can reach up to 20M (which can be increased to 25M by software

upgrade from December, 2010).

From Oct. 1, 2010, ZTE stops delivering RSU60/R8860, and

deliver RSU60E and R8860E instead.

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RSU60E and R8860E Difference in names for RSU60/RSU60E

　 RSU60/RSU60E Remarks

Name defined by pre-sales engineers

RSU60

We do not distinguish the new module and the old one in the pre-sales stage, and needs not inform the customer about it.

Name configured in ECC RSU60 RSU60E Add E to distinguish both of them

Name in the shipping list RSU60 RSU60E 　

Name in the label RSU60 RSU60E The label of RSU60 and that of RSU60E are different.

Name displayed on NMs RSU60 RSU60E 　

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RSU60E and R8860E Names of R8860/R8860E in different systems

　 R8860 RemarksName defined by pre-sales

engineers R8860

Name configured in ECC R8860 GU**8 (DC) R8860 GU**8 (DC/E) Add E to distinguish both of them

Name in the shipping listZXSDR R8860 GU**8 RA

(DC, TX ***MHz-***MHz)

ZXSDR R8860 GU**8 RA (DC, TX ***MHz-***MHz) (V1.10)

　

Name in the labelZXSDR R8860 GU**8 RA

(DC, TX ***MHz-***MHz)

ZXSDR R8860 GU**8 RA (DC, TX ***MHz-

***MHz)

No difference for labels of

R8860 (but different in

appearance)

Name displayed on NMs R8860 (DTR-GUxxx) R8860 (ADTR-GUxxx) 　

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RSU60E and R8860E Difference in appearance

RSU60 Vs RSU60E

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RSU60E and R8860E Difference in appearance R8860 Vs R8860E

R8860 R8860E

Wide

Depth

HeightWide

Depth

Height

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RSU60E and R8860E Difference in NM interfaces

RSU60 Vs RSU60E

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RSU60E and R8860E Difference in NM interfaces

R8860 Vs R8860E


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Fiber interfaces

Each FS board supports 6 fiber interfaces.

Each RU supports 2 fiber interfaces.

The fiber supports both star-type and link-type networking

For link-type networking, at most 4 RUs can be connected in

cascading mode.

BBU is at most 40 Km away from the RU.

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CPRI interface configuration rules

BBU is configured with commercial-level SFP: 1.25G/1310nm single mode

optical module with transmitting and receiving integrated

RSU is configured with industrial-level SFP: 1.25G/1310nm single mode

optical module with transmitting and receiving integrated

RRU has been configured SFP itself, so it is unnecessary to configure

additional SFP.

Fibers between BBU and RSU need not be configured separately. Number

of fibers to be delivered depends on the quantity of RSUs, and it will not be

configured on ECC.

CPRI of the BS8800 main cabinet uses the electrical interface and high-

speed cables. That of both the main cabinet and the extension cabinet use

the optical interface.


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High integration

BBU supports 60 TRXs. RU supports 6TRX/2TRX. A fiber can support 24 TRX Support smooth evolution to LTE and HSPA+ All IP transmission based structure Support multi-band RRU

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Flexible structure

Support macro-base station Support remote RU Support both FE/GE and E1/T1 Support both indoor and outdoor requirements Small volume and light weight Energy efficient Support evolution of the technology

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Multiple new functions

Baseband frequency hopping Transmitting and receiving diversity Combine multiple carriers Applied for express railways

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Basic concept – baseband frequency hopping

Frequency hopping refers to that multiple frequencies are used for radio transmission of a single speech/signaling/data link. The transmission frequency keeps stable within the transmission period of a burst pulse. For different burse pulses of the same link, the transmission frequency may change. The MS may be affected by the fading effect of some frequency on the transmission path. GSM coding and inter-leaving technology helps to minimize the impact of single-burst lost to the voice quality.

Baseband frequency hopping means that multiple transmitters work on their respective frequencies, and switch signals of different channels to different transmitters to send them on the baseband, thus to achieve the function of frequency hopping.

The function of frequency hopping is easy and feasible. Because of limited number of TRXs, there are a just a few frequencies available for frequency hopping.

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Baseband frequency hopping technology

For baseband frequency hopping, each RU has a fixed frequency. The baseband board figures out the frequency of each timeslot over the TDMA frame according to frame No. (FN), mobile allocation table (MA), mobile allocation index offset (MAIO), and frequency hopping serial No. (HSN). Then, the baseband board switches the data to the corresponding RU according to the frequency, and receives uplink data from the corresponding RU. The baseband frequency hopping can be implemented by DSP, or FS or FPGA on the BP board. At present, a DSP processes one frequency hopping group, which can have 12 frequencies at most.

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Basic concept – MCUM

Multi-carrier unite combine (MCUM) is a product after 3G OTSR

is introduced into the GSM system.

To meet complex requirements for coverage and high-speed

moving, antennas are placed at multiple positions and multiple

angles to cover each single cell.

The SDR solves the problem about antenna extension and

repeaters by distributing the RRU remotely.

Downlink signals of multiple RRUs are same. The uplink

perform selective combination, that is, MCUM.

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Coverage map of express railways

Cell 1

Cell 2

Cell n

BBU

Abis 口

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Features of the technology The downlink of multiple carriers are same signals. TRXs of an RU should be processed on the same UBPG. A

UPBG can process 12 TRXs at most. Uplink signals are combined selectively, which can improve

sensitivity. Quantity of configured RUs increases. Quantity of configured UBPGs increases.

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Lower cost

Reduce the cost per unit Reduce the cost of typical networking Reduce the operation cost Reduce the maintenance cost

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Review

Basic concepts of SDR SDR hardware and software structure 3 types of SDR base stations Functions of each SDR board Various interface of SDR

01.Introduction to GU SDR BTS

Documents

Transcript of 01.Introduction to GU SDR BTS