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Family of RBS 3000 products for WCDMA systems


									  Family of RBS 3000 products for WCDMA systems
  Pierre Zune

Ericsson is the first company to take WCDMA technology out of the labo-                   • to control mobility (the RBS provides the
ratory and test it in a real environment. At the end of 1999, Ericsson had                  actual radio resources); and
seventeen WCDMA test systems in operation in Asia, Europe and North                       • to maintain radio links.
America.                                                                                  The RNC is connected to the core network
   The RBS 3000 product line is a comprehensive family of macro, mini                     via the Iu interface; user equipment (UE) is
                                                                                          connected to the RBS via the Uu interface
and micro radio base stations (RBS) that were designed using input from
                                                                                          (the air interface). RNCs are interconnected
second-generation mobile systems.                                                         within the radio access network via the Iur
   In this article, the author gives an in-depth description of Ericsson’s                interface; and the RBSs are connected to the
family of RBS 3000 products.                                                              RNC via the Iub interface.

                                                                                          The family of RBS 3000 products consists
                                                                                          of base stations for both indoor and outdoor
                                         Overview of the WCDMA                            installations, as well as single-sector and
                                         radio access network                             multiple-sector configurations. The prod-
                                                                                          uct architecture supports several configura-
                                         Ericsson’s WCDMA radio access network            tions and establishes a basis for future de-
                                         (RAN) consists of radio network controllers      velopment of RBSs that support macro-,
                                         (RNC), radio base stations (RBS), RAN op-        micro- and picocell structures.
                                         eration support (RANOS) and tools for radio         The range of RBS 3000 models gives oper-
                                         access management (TRAM). In Third-gen-          ators cost-effective solutions to capacity, cov-
                                         eration Partnership Project (3GPP) specifi-      erage, power supply, space and environmen-
                                         cations, the RBS corresponds to Node B           tal requirements in network configurations.
                                         (Figure 1).
                                         RNC                                              The tools for radio access management aid
                                         The main tasks of the RNC are                    operators in designing, testing, and opti-
                                         • to manage radio-access bearers for trans-      mizing the performance of radio and trans-
                                           porting user data;                             port networks. Configuration data can be
                                         • to manage and optimize radio network re-       downloaded from TRAM to the RNCs and
                                           sources;                                       RBSs via RANOS.

Figure 1
Overview of the radio network, logical
                                                                                                Network          CN and other
                                                                                                management       management
                                                 Core network                                   system

                                               Radio access             Iu                              RANOS        TRAM
                                                                                                                  Tools for radio access
                                                                       Iur                                        management
                                               Radio network                                                  Radio access network
                                               controller                                                     operation suport

                                                  Radio base
                                                  station                                                             Services

                                                                                       User equipment

170                                                                                                             Ericsson Review No. 3, 2000
RANOS                                                 number of simultaneous users, carriers, and
RANOS, which is the software for handling op-         sectors, by adding hardware boards or extra
eration and maintenance tasks for the WCDMA           cabinets.
radio-access network, gives operators a consolidat-
ed view of information on alarms, configurations,     RBS 3000 macro products
and basic performance. It also provides interfaces    All RBS 3000 macro products have been de-
for easy integration into other management envi-      signed to handle a variety of services. The
ronments.                                             RBS hardware and software feature a mod-
                                                      ular design. The RBS hardware is flexible,
                                                      meaning that the same equipment can han-
RBS 3000 family                                       dle most traffic situations. The architecture
The design of Ericsson’s family of RBS                is scalable and thereby easy to expand. Op-
3000 products is based on 3GPP require-               erators can add extra carriers or more chan-
ments. All RBS 3000 products are pre-test-            nel capacity by installing additional boards
ed and pre-configured before delivery to              or another complete cabinet.
the site. They also include a built-in self-
test mechanism and an equipment config-               RBS 3202
uration wizard, which further reduce in-              The RBS 3202 (Figure 2) is an indoor macro
stallation time and speed up network roll-            radio base station. The basic configuration
out.                                                  supports up to three sectors and two carri-
  A single RBS 3000 equipment configu-                ers (3x2). The RBS can be extended to con-
ration handles mixes of voice, circuit-               figurations of three sectors and four carriers
switched and packet-data services without             (3x4) or six sectors and two carriers (6x2).
having to be reconfigured for each different          The output power is 20/40 W radio fre-
kind of traffic.                                      quency (RF) per carrier.                          Figure 2
  Operators can easily increase coverage, the            All units in the cabinet are easily accessi-   Description of the hardware structure in
                                                                                                        RBS 3000. Photograph of an RBS 3202.


  3GPP        Third-generation Partnership Pro-        O&M         Operation and maintenance
              ject                                     OMC         Operation and maintenance center
  ATM         Asynchronous transfer mode               PBC         Power and battery cabinet
  BP          Board processor                          RAN         Radio access network
  BSC         Base station controller                  RANOS       RAN operation support
  BTS         Base transceiver station                 RBS         Radio base station
  CBN         Common bonding network                   RET         Remote electrical antenna tilt
  C/I         Carrier-to-interference ratio            RF          Radio frequency
  CORBA       Common object request broker             RNC         Radio network controller
              architecture                             RRU         Remote radio unit
  CU          Capacity unit                            RTOS        Real-time operating system
  dB          Decibel                                  RX          Receiver
  dBm         Decibel relative to 1 mW                 STM         Synchronous transfer mode [syn-
  DDTMA       Dual-duplex TMA                                      chronous transport module]
  DL          Downlink                                 SW          Software
  DPX         Duplex                                   TMA         Tower-mounted amplifier
  EACU        External alarm connection unit           TMS         Test mobile station (terminal)
  EMC         Electromagnetic compatibility            TRAM        Tools for radio access manage-
  ET          Exchange terminal                                    ment
  ETB         ET board                                 TRX         Transceiver
  FDD         Frequency division duplex                TU          Timing unit
  HTTP        Hypertext transfer protocol              TX          Transmitter
  HW          Hardware                                 UE          User equipment
  IDM         Internal distribution module             UL          Uplink
  IP          Internet protocol                        UMTS        Universal mobile telephony system
  IPsec       IP security protocol                     UTRAN       UMTS terrestrial radio access net-
  Java applet Distributed embedded Java pro-                       work
              gram that runs on a Web browser          VAC         Volts, alternating current
  MCPA        Multi-carrier power amplifier            VDC         Volts, direct current
  MMI         Man-machine interface                    WCDMA       Wideband code-division multiple
  MTBF        Mean time between failures                           access
  NMS         Network management system                wTRU        Wideband transceiver unit

Ericsson Review No. 3, 2000                                                                                                                   171
                                ble from the front of the cabinet. All cable     RF parts have been moved closer to the an-
                                interfaces are located at the top of the cabi-   tenna, which means that a smaller power
                                net. Thus, the cabinets can be mounted side-     amplifier is used. Also, the radio parts are
                                by-side or back-to-back.                         made smaller, which further reduces power
                                                                                 consumption. Less power consumption
                                RBS 3101                                         means less heat, which means that the RBS
                                The RBS 3101 (Figure 3) is an outdoor macro      can use convection cooling without any
                                radio base station. It supports the same range   moving fans—no noise. The main unit,
                                of configurations as the RBS 3202. The out-      which contains the transmission interface to
                                put power is 20/40 W RF per carrier.             the RNC,
                                   The RBS 3101 features a weatherproof          • performs all system-level diagnostics;
                                cabinet for outdoor sites with high capacity     • provides system timing via the transmis-
                                and high coverage. The cabinet contains in-        sion interface source;
                                tegrated power supply with backup batter-        • controls power and processes calls, en-
                                ies, space for transmission equipment, and         codes and decodes WCDMA; and
Figure 3
                                a climate package. The RBS 3101 supports         • handles softer handovers.
RBS 3101.                       50 Hz and 60 Hz systems and can be pow-          Some advantages of the main-remote con-
                                ered with single- or triple-phase AC.            cept are
                                                                                 • easy and rapid installation—the main
                                RBS 3000 main-remote concept                       unit and remote radio unit can be placed
                                                                                   several kilometers apart, which means
                                Macrocell coverage in a microcell package          that the RBS can be installed practically
                                Site acquisition is an increasingly time con-      anywhere;
                                suming and costly problem, especially in         • the main units and RRU can be hand-
                                busy urban environments. Ericsson’s solu-          carried to a rooftop;
                                tion to this problem is the main-remote con-     • macro coverage from wideband transceiv-
                                cept. At conventional site installations, all      er unit (wTRU) and mini RBS solutions;
                                equipment, including digital parts, radio          and
                                parts, and combiners are housed in one cab-      • greatly reduced power consumption
                                inet. However, according to Ericsson’s             (compared to the macro RBS).
                                main-remote concept, the RF and digital          RBS 3000 main-remote products include
                                baseband parts are separated by an optical       the RBS 3401, RBS 3501, and the wTRU
                                interface in a remote radio unit (RRU). The      concept.

Figure 4
Main-remote concept RBS 3401.

                                                                                 Remote radio units

                                                Main unit

172                                                                                                   Ericsson Review No. 3, 2000
RBS 3401
The RBS 3401 (Figure 4) is an indoor mini
RBS. It weighs less than 30 kg and can be
mounted on the wall or in a standard 19-
inch rack. It can be delivered with an inte-
grated power supply for single-phase AC,
–48 VDC or +24 VDC. An optional exter-
nal battery backup cabinet can be connect-
ed to provide extended backup time. When
used together with remote radio units and
an optional external backup battery cabinet,
the RBS 3401 constitutes a compact but
complete macro base station solution.
RBS 3501
                                                                                             Remote radio units
The RBS 3501 (Figure 5) is an outdoor mini
RBS with a complete RBS system housed in                         Main unit
a compact convection-cooled, weatherproof
cabinet. The RBS 3501 offers macrocell cov-
erage in a microcell package and can serve
as either a traditional macrocell or microcell
base station.
   The main unit can be mounted practical-          Figure 5
                                                    Main-remote concept RBS 3501.
ly anywhere—on a wall, pole, the side of a
building, or rooftop. Its compact size and
low weight (with remote radio units) enable
it to be hand-carried to the installation site.   WCDMA capacity in a GSM network. The
The RBS 3501 is powered by single-phase           wTRU can be installed in any Ericsson
AC, –48 VDC or +24 VDC.                           RBS 2000 macro cabinet. It occupies two
                                                  TRU slots and shares the GSM cabinet’s
wTRU concept                                      power and cooling resources with other
The wTRU concept (Figure 6) is a cost-            units. The wTRU supports one carrier and
effective solution for rapid roll-out of          one to three sectors.

                                                                                             Figure 6
                                                                                             wTRU concept.

Ericsson Review No. 3, 2000                                                                                       173
                                                    Remote radio unit                                  Power can also be supplied via the optional
                                                    The remote radio unit (Figure 7), which is         power and battery cabinet (PBC).
                                                    a radio head with up to 10 W RF output
                                                    power, is used together with the RBS 3401,         RBS 3000 micro products
                                                    RBS 3501 or wTRU. It can also be used with         Designers of the micro RBS drew heavily on
                                                    the micro RBS 3301 to provide extended             experiences gained in working with micro-
                                                    coverage. The remote radio unit houses an          and picobase stations for second-generation
                                                    RF filter, power amplifier, RX low-noise           mobile phone systems. The exterior of the
                                                    amplifier, and transceiver (TRX) for one sec-      micro RBS is both weatherproof and dis-
                                                    tor carrier. It also supports RX space diver-      crete. This small, light-weight RBS can eas-
                                                    sity. The unit can be placed together with         ily be installed by one person.
                                                    the cabinet, on a rooftop, or on the tower
                                                    near the antenna.                                  RBS 3301
                                                       An optical digital interface connects the       The RBS 3301 is suitable for indoor and out-
Figure 7                                            main unit and the remote radio unit. This          door use (Figure 8). The cabinet houses one
Remote radio unit.                                  ensures high performance and enables oper-         transceiver and all necessary equipment for
                                                    ators to place the remote radio unit up to         serving one cell. Convection cooling further
                                                    several kilometers from the main unit. Since       contributes to a compact and weatherproof
                                                    various different main units support the           cabinet. The RBS 3301 has one carrier with
                                                    same optical digital interface, operators can      omni-directional or sector-based coverage at
                                                    reuse remote radio units when they upgrade         1 W RF output power. Optional equipment
                                                    the main unit, say, to increase capacity.          includes an external antenna, an RRU (for
                                                       The weatherproof RRU is suitable for in-        macro coverage), and a power and battery
                                                    door and outdoor use. It generates no sig-         cabinet.
                                                    nificant acoustic noise, because only con-            The micro RBS has the same basic func-
                                                    ventional cooling is used. It is powered by        tionality as the macro RBS but with less ca-
                                                    –48 VDC, +24 VDC or single-phase AC.               pacity and coverage. The transceiver and
                                                                                                       power amplifier have been integrated into the
                                                                                                       RBS cabinet using ASIC technology. This de-
                                                                                                       sign yields high availability, small volume,
                                                                                                       low weight and low power consumption.
                                                                                                          Backup power for short interruptions to
                                                                                                       the AC power supply is built-in. An extra
BOX B, THE RBS 3000 FAMILY OF PRODUCTS                                                                 power and battery cabinet can be connected
                                                                                                       to extend backup power. Moreover, the re-
RBS 3101 outdoor macro                             RBS 3501 outdoor mini                               mote radio unit can be used with the RBS
The RBS 3101 is an outdoor RBS with one to         The RBS 3501 is a compact, convection-              3301 to increase coverage.
four carriers and one to six sectors at 20/40W     cooled, weatherproof, outdoor RBS with the
RF output power per carrier. The power distri-     same specifications as the RBS 3401. Thanks
bution system and battery backup have been         to its compact design, it can be hand-carried to
                                                                                                       Operation and maintenance
integrated into the cabinet. External power is     the installation site.
230/380 VAC.                                                                                           Rapid implementation
                                                   Remote radio unit                                   One goal when designing the RBS 3000 was
RBS 3202 indoor macro                              The remote radio unit is a remote radio head
The RBS 3202 is an indoor RBS with one to four     with a transceiver and power amplifier. It has up   to make installation and commissioning
carriers and one to six sectors at 20/40 W RF      to 10 W RF output power and can be connect-         rapid and easy. The RBS 3000 is thus pre-
output power per carrier.                          ed via a digital interface to the RBS 3401/RBS      tested and pre-configured before it is deliv-
                                                   3501, RBS 3301 and wTRU.                            ered to the site—all hardware and software
RBS 3301 micro
The RBS 3301 is a small, lightweight, weather-     wTRU concept
                                                                                                       are configured at the factory. During in-
proof base station with no floor space require-    The wideband transceiver unit (wTRU) concept        stallation, field technicians need only enter
ments. It has one carrier and one sector at 2 W    gives operators a rapid and smooth way of           a few site-specific parameters (IP address,
integrated RF output power, and can be used        implementing WCDMA coverage. The wTRU               site name, and so on) via a Web browser on
with an optional remote radio unit for extended    occupies two TRU slots in a GSM RBS 2000            a standard laptop computer. Built-in com-
coverage.                                          cabinet. When used with remote radio units, the
                                                   wTRU concept yields one carrier and one to          missioning software gives field technicians
RBS 3401 indoor mini                               three sector coverage.                              access to every function in the RBS 3000.
The RBS 3401 is a compact indoor mini RBS
with                                               Pre-assembled site solutions                        Live expansion
• three sectors and one to two carriers per sec-   Every RBS in the family of RBS 3000 products
  tor; or                                          can be delivered in pre-assembled outdoor con-
                                                                                                       Without shutting down power or disturb-
• six sectors and one carrier per sector.          tainers which include all the equipment that is     ing traffic, operators can increase capacity
Macro coverage is achieved using remote radio      needed to build a complete site.                    and coverage by adding boards to the
units.                                                                                                 RBS 3000.

174                                                                                                                        Ericsson Review No. 3, 2000
Hot-repair hardware maintenance                  terfaces between hardware units have been
When developing the RBS 3000, designers          clearly defined, and most will be maintained
put special emphasis on minimum system           throughout product evolution. This flexible
downtime and low maintenance costs. They         design means that new releases of hardware
achieved these design objectives by means        units and boards based on advanced ASIC
of the hot-repair maintenance principle of       technology can easily replace or be added to
replacing units that have been affected by       older units, enabling an increase in channel
faults. By hot repair we mean that a faulty      capacity, for example.
unit can be replaced with minimum impact
on traffic handled by the RBS 3000.              Redundancy
  The RBS 3000 products can be accessed          Depending on the operator’s needs, the RBS
for the execution of management tasks from       can be equipped for minimum hardware              Figure 8
                                                                                                   RBS 3301.
any node in the network. The RBS 3000 can        configuration or high redundancy. Redun-
locate the root cause of faults.                 dancy is based on the n+1 principle—that
                                                 is, if one unit fails, another unit takes over,
Power-saving mode                                thereby guaranteeing full capacity in the
An optional function enables operators to        RBS. In terms of load sharing, if a unit fails,
order RBS 3000 nodes into power-saving           the functionality is maintained but capaci-
mode in order to lower overall power con-        ty abates.
                                                 Architecture of the hardware units
Support for most transmission standards          The RBS 3000 macro products are made up
The RBS 3000 supports most transmission          of a baseband subrack, radio subrack, multi-
standards. Cascading, star, and tree trans-      carrier power amplifier (MCPA) subrack,
mission configurations can be combined to        power-distribution equipment, tower-
support different network structures.            mounted amplifier (TMA), and a remote
                                                 electrical antenna tilt (RET).
High availability thanks to many
redundancy concepts                              Baseband subrack
The RBS 3000 includes several redundancy         The baseband subrack is composed of ex-
concepts (such as n+1 redundancy, load           change terminal boards (ETB), a timing unit
sharing, and processor cluster) for increased    board and an ATM switch board. The base-
availability and reduced downtime.               band subrack also contains boards for up-
                                                 link/downlink functions for coding, inter-
                                                 leaving, and modulation. The built-in ATM
Hardware architecture                            switch board distributes incoming informa-
                                                 tion from the transport link to radio-
Platform                                         channel hardware.
Ericsson’s WCDMA product portfolio is
based on a new platform, which is well suit-     Radio subrack
ed to building small-to-medium-scale             The radio subrack contains the main proces-
telecommunications products that require         sor of the RBS, an antenna interface unit
low-cost support for asynchronous transfer       (AIU), and boards with radio functionality.
mode (ATM) and IP transport.1 Both the           It also contains boards for handling digital-
RNC and RBS are based on this platform,          to-analog (D/A) signal conversion, modula-
which includes all the physical equipment        tion and demodulation, analog-to-digital
and associated software needed to create a       (A/D) signal conversion and filtering for the
packet-switching network node. The modu-         RX path for each cell carrier. The AIU is
lar design of the platform makes it easy for     composed of radio frequency (RF) parts,
operators to create nodes with different con-    such as RF filters, a low-noise amplifier, and
figurations, functionality, capacity and reli-   splitters. Duplex filters minimize the num-
ability. Transport can be concentrated in any    ber of feeders and antennas by allowing re-
node, since every node has ATM switching         ceiver and transmitter path connections to
capabilities.                                    be made to a common antenna.

Hardware structure                               MCPA subrack
The family of RBS 3000 products features         The MCPA unit, which is a wideband lin-
a modular design: several subsystems facil-      ear power amplifier, amplifies the carriers to
itate easy expansion and evolution. The in-      be transmitted in a cell.

Ericsson Review No. 3, 2000                                                                                    175
                                                                                       design uses the same feeder for receiving and
                                      RBS application
                                            software                                   transmitting signals.
                                                                                         The TMA embodies two transmitter (TX)
                                                                                       and receiver (RX) branches in one unit.
                                                                                       Thus, only one TMA is needed per sector.
                                                                                       Power is supplied via the RF feeder from the
                                                                                       AIU in the RBS.
                                                                                       Remote electrical antenna tilt
                                                                                       The remote electrical antenna tilt controls
                                                                                       the vertical tilt angle of the antenna lobe.
                                                                  RBS platform
                                                                                       The tilt angle ranges from 0 to X degrees
Figure 9                                                                               downtilt, where X is the vertical
RBS software structure.
                                                                                       beamwidth of the antenna. The maximum
                                                                                       downtilt angle approximately corresponds
                                                                                       to the first upper null in the vertical radia-
                                      Power distribution equipment                     tion pattern. If a TMA is used, the RET is
                                      The RBS is equipped with a capacitor unit        powered by the AIU via the TMA; other-
                                      (CU) that keeps the RBS in operation dur-        wise, the RET is powered directly from the
                                      ing short drops in –48V power. An external       AIU.
                                      alarm connection unit (EACU) can also be
                                      connected to the RBS 3000. Operators can
                                      define up to 32 external alarms and two out-
                                                                                       Software architecture
                                      put control ports. The alarms are galvani-
                                      cally separated from the RBS.                    General
                                                                                       All software can be downloaded to the
                                      Tower-mounted amplifier                          RBS 3000 before it is shipped and
                                      The low-noise amplifier, which is mounted        installed. The software is stored in non-
                                      on the antenna tower near the antenna, is        volatile program store in the main proces-
                                      used on receiving paths in order to lower the    sor. Besides simplifying and accelerating
                                      overall receiver noise figure. It is a dual-     installation, this design also speeds up
                                      duplex TMA (DDTMA), which means it in-           recovery after power failures, since it
                                      cludes two duplex filters per branch. This       eliminates the need for reloading software
                                                                                       from other nodes.
                                                                                          The RBS 3000 software is composed of
                                                                                       several subsystems in a layered architecture.
                                                                                       The software platform, which provides basic
Figure 10                                 Base station control                         support for application software, includes an
RBS application software structure.
                                                Logical resource support
                                                                                       execution platform with operating system,
                                                                                       ATM transport, and operation and mainte-
                                                        Equipment control
                                                                                       nance (O&M) infrastructure. The RBS ap-
                                                                                       plication software is built on the platform
                                                                       Operation and   software and handles the RBS hardware
                                                                       support         (Figure 9).

                                                                                       RBS application software
                                                                                       The application software is divided into sev-
                                                                                       eral subsystems in a layered structure (Fig-
                                                                                       ure 10).
                                                                                       Base station controller
                                                                                       The base station controller (BSC) subsystem
                                                                                       is a service layer that interprets and executes
                                                                                       the application procedures initiated from
                                       Hardware                                        the RNC.
                                                     Firmware                          Logical resource support
                                                Board processor
                                             Main processor software                   Logical resource support provides the ser-
                                                                                       vice layer with control over RBS logical re-

176                                                                                                         Ericsson Review No. 3, 2000
sources, such as radio links, cell carriers,                 Low-level communication
ATM connections, and so on.                                  support
                                                                       Device function control
Equipment control                                                                         Board control
The main purpose of the equipment control                                         ard
subsystem is to isolate the hardware imple-                                                ce
mentation from higher layers. It contains
device board control functions, hardware
resource-allocation algorithms and a

control-signal transport-routing function.

Hardware layer

The hardware layer is divided into several
device-specific subsystems that contain
hardware and software. Each subsystem has
a software component in the board proces-
sor of individual device boards. The associ-                                                                 Figure 11
                                                                    Hardware (DSP, ASIC, etc.)               Application structure of the device board.
ated software is generally divided into three
parts (Figure 11):
• a device-specific component, which is
   unique to different types of hardware;
• a board control component, which han-          The design is based on 3GPP requirements.
   dles O&M functionality (for instance,            The macro models consist of a weatherproof
   starting and loading) for the board—this      outdoor model and an indoor model. Mini-
   component is common to all RBS device         and microbase stations can be mounted on
   boards; and                                   walls or poles, saving floor space. Remote
• a low-level communication component—           radio units can be located near the antenna
   this component is also common to all RBS      apart from the rest of the base station equip-
   device boards.                                ment. This design reduces feeder losses and
                                                 increases the capacity of the base station.
RBS software platform                               For the migration from GSM to
The RBS software platform provides               WCDMA, an individual WCDMA trans-
services for the application software. These     ceiver (wTRU) can be plugged into empty
services are an ATM platform, a distrib-         slots in existing GSM RBS 2000 macrobase
uted real-time system, basic O&M, man-           stations to provide the fastest possible roll-
agement interfaces, and transport services       out of WCDMA coverage and capacity.
(Figure 12).                                        The RBS 3000 products can be accessed
  The RBS application software is distrib-       for the execution of management tasks from                  1 Reinius, J.: Cello—An ATM transport and
uted over several processors using the inter-    any node in the network. The RBS 3000 has                     control platform. Ericsson Review Vol.
                                                                                                               76(1999):2, pp. 48-55.
processor communication offered by the           been designed to accept software corrections
platform. The main processors of the             and upgrades while it is in service. Similar-
RBS 3000 cooperate to form a main proces-        ly, the RBS plug-in units can be replaced in
sor cluster (MPC) that executes most of the      accordance with the hot-repair principle,
control software. The processors that make       and RBS hardware can be installed while the
up the MPC are equal in terms of control—        RBS 3000 is in operation.
that is, there are no master-slave relation-
ships between them. However, if one of the
processors fails, the program execution is                                                                   Figure12
                                                        BP                           BP
moved to another main processor in the                                                                       Processor cluster.
MPC. For control, most boards are equipped
with a board processor (BP). Those units                                                                BP
that do not contain a board processor are                           MP
monitored by other units.
Conclusion                                         BP

Ericsson’s family of RBS 3000 products for
WCDMA includes indoor and outdoor ver-
sions of macro-, mini- and microbase stations.

Ericsson Review No. 3, 2000                                                                                                                        177

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