Nokia Rnc Architecture

7/18/2019 Nokia Rnc Architecture

http://slidepdf.com/reader/full/nokia-rnc-architecture 1/159

RNC Architecture and functionality 1

- Nokia RNC Architecture -

Copyright © Nokia Networks Oy 2006

RNC Architecture and functionality-

Nokia RNC Architecture






The information in this document is subject to change without notice and describes onlythe product defined in the introduction of this documentation. This document is intendedfor the use of Nokia Networks' customers only for the purposes of the agreement under

which the document is submitted, and no part of it may be reproduced or transmitted inany form or means without the prior written permission of Nokia Networks. Thedocument has been prepared to be used by professional and properly trained personnel,and the customer assumes full responsibility when using it. Nokia Networks welcomescustomer comments as part of the process of continuous development and improvementof the documentation.

The information or statements given in this document concerning the suitability, capacity,or performance of the mentioned hardware or software products cannot be consideredbinding but shall be defined in the agreement made between Nokia Networks and thecustomer. However, Nokia Networks has made all reasonable efforts to ensure that theinstructions contained in the document are adequate and free of material errors andomissions. Nokia Networks will, if necessary, explain issues which may not be coveredby the document.

Nokia Networks' liability for any errors in the document is limited to the documentarycorrection of errors. Nokia Networks WILL NOT BE RESPONSIBLE IN ANY EVENTFOR ERRORS IN THIS DOCUMENT OR FOR ANY DAMAGES, INCIDENTAL ORCONSEQUENTIAL (INCLUDING MONETARY LOSSES), that might arise from the useof this document or the information in it.

This document and the product it describes are considered protected by copyrightaccording to the applicable laws.

NOKIA logo is a registered trademark of Nokia Corporation.

Other product names mentioned in this document may be trademarks of their respectivecompanies, and they are mentioned for identification purposes only.

Copyright © Nokia Networks Oy 2006. All rights reserved.






Table of Contents:

1. Nokia RNC Architecture.........................................................................................10 2. Data Flow in the RNC............................................................................................10

2.1. Data flow in the control pane...........................................................................11 2.1.1.

Permanent Signalling Links....................................................................11

2.1.2. Common Control Channels ....................................................................15 2.1.3. Dedicated Control Channels...................................................................22 2.1.4 Summary......................................................................................................25

2.2. Data flow in the user pane...............................................................................26 2.2.1. User data between UE and CS-CN ........................................................26 2.2.2. User data between UE and PS-CN ........................................................31 2.2.3. Summary................................................................................................34

3. RNC architecture overview....................................................................................35 3.1. Functional units of the RNC ............................................................................36 3.1.1. RNC196 and RNC450................................................................................36

3.1.2. ICSU ......................................................................................................37 3.1.3. RRMU....................................................................................................38 3.1.4. RSMU ....................................................................................................39 3.1.5. GTPU.....................................................................................................40 3.1.6. DMCU....................................................................................................41 3.1.7. OMU ......................................................................................................42 3.1.8. WDU for OMU........................................................................................43 3.1.9. FDU .......................................................................................................44 3.1.10. SFU........................................................................................................45 3.1.11. MXU.......................................................................................................46 3.1.12. A2SU .....................................................................................................47 3.1.13. NIS1 / NIS1P..........................................................................................48 3.1.14. NIP1.......................................................................................................49 3.1.15. TBU........................................................................................................50 3.1.16. EHU .......................................................................................................51 3.1.17. NEMU ....................................................................................................52 3.1.18. WDU for NEMU......................................................................................53 3.1.19. ESA24....................................................................................................54 3.1.20. Subrack Power Distribution ....................................................................55

3.2. Exercise ..........................................................................................................56 4. Computing Units....................................................................................................57

4.1. ICSU ...............................................................................................................57 4.1.1. Interface Control and Signalling Unit (ICSU) ..........................................57 4.1.2. Radio Resource Management Unit (RRMU)...........................................59 4.1.3. Resource and Switch Management Unit (RSMU)...................................60 4.1.4. GPRS Tunnelling Protocol Unit (GTPU) .................................................61 4.1.5. Operation and Maintenance Unit (OMU) ................................................62 4.1.6. Exercise .................................................................................................65

5. Signal Processing Unit...........................................................................................66 5.1. DMCU tasks....................................................................................................66

5.1.1. Macrodiversity Combining......................................................................66 5.1.2. Uplink Outer Loop Power Control...........................................................67 5.1.3. Downlink Outer Loop Power Control ......................................................68 5.1.4. Frame Protocol.......................................................................................69






5.1.5. MAC Protocol Processing ......................................................................70 5.1.6. Ciphering................................................................................................71 5.1.7. RLC Protocol Processing .......................................................................72 5.1.8. PDCP Protocol Processing.....................................................................73 5.1.9. DMCU Tasks: Summary.........................................................................74

5.2.

Exercise ..........................................................................................................75

6. Switching & Multiplexing Units...............................................................................76 6.1. ATM Switching Fabric Unit (SFU)....................................................................76

6.1.1. Switching Fabric Unit (SFU) ...................................................................76 6.2. ATM Multiplexer Unit (MXU)............................................................................79

6.2.1. Multiplexer Unit (MXU) ...........................................................................79 6.3. AAL2 Switching Unit (A2SU) ...........................................................................80

6.3.1. AAL2 Switching Unit (A2SU) ..................................................................80 6.4. Exercise ..........................................................................................................82

7. Physical Interfaces / Network Interface Units......................................................... 83 7.1. SDH interfaces................................................................................................83

7.1.1. Physical Interface Unit NIS1...................................................................83 7.1.2. SDH Functions.......................................................................................84 7.1.3. ATM-layer Functions ..............................................................................85 7.1.4. O&M Functions ......................................................................................86 7.1.5. ATM traffic over STM-1 ..........................................................................87 7.1.6. Multiplex Section Protection (MSP) ........................................................88

7.2. PDH Interfaces................................................................................................88 7.2.1. Physical Interface Unit NIP1...................................................................88 7.2.2. Inverse Multiplexing for ATM (IMA) ........................................................89

7.3. Exercise ..........................................................................................................90 8. Timing and Hardware Management (TBU) ............................................................90

8.1. Synchronisation...............................................................................................91 8.2. Hardware Management and Supervision.........................................................92 8.3. Exercise ..........................................................................................................93

9. External Alarm Units..............................................................................................94 9.1. EHU ................................................................................................................94

9.1.1. External Hardware Alarm Unit (EHU) .....................................................94 9.2. Exercise ..........................................................................................................96

10. Element Management........................................................................................96 10.1. NEMU Tasks..............................................................................................97 10.2. NEMU in a nutshell ....................................................................................98 10.3. Exercise.....................................................................................................99

11. Mechanics and Power Supply............................................................................99 11.1. Basic Concepts........................................................................................ 100 11.2. Power Supply...........................................................................................102 11.3. ROHS ......................................................................................................103 11.4. Exercise...................................................................................................104

12. Reliability and Redundancy Principles .............................................................105 12.1. Reliability of the RNC...............................................................................105

12.1.1. Reliability of the RNC ...........................................................................105 12.1.2. High availability ....................................................................................106 12.1.3. Maintenance design objectives ............................................................107

12.2. Redundancy Principles ............................................................................107 12.2.1. Four types of redundancy.....................................................................107






12.2.2. 2N Redundancy (Duplication)...............................................................108 12.2.3. N+1 Redundancy (Replacement) .........................................................109 12.2.4. SN+ Redundancy (Load Sharing).........................................................110 12.2.5. No Redundancy ...................................................................................111

12.3. Redundancy of Functional Units ..............................................................112 12.3.1.

Redundancy of Functional Units...........................................................112

12.3.2. Power Supply Redundancy ..................................................................112

12.4. Exercise...................................................................................................113 13. RNC Capacity Steps........................................................................................114

13.1. Capacity Steps in the RNC.......................................................................114 13.1.1. Capacity Step 1....................................................................................114 13.1.2. Capacity Step 2....................................................................................118 13.1.3. Capacity Step 3....................................................................................122 13.1.4. Capacity Step 4....................................................................................124 13.1.5. Capacity Step 5....................................................................................126

13.2. Upgrade RNC196 to higher capacity........................................................128 13.2.1 RNC196 capacity Steps 6 (RNC196/300) and 7 (RNC196/450)................129 13.2.2 RNC196 capacity Step 6 (RNC196/300)...................................................130 13.2.3 RNC196 capacity step 7 (RNC196/450)....................................................131

13.3. Optional Upgrade ...........................................................................................133 13.3. RNC HSDPA connectivity and capacity....................................................138 13.4. Exercise...................................................................................................139

14. RNC450 RN2.2 New Delivery..........................................................................139 14.1. Capacity Steps.........................................................................................140

14.1.1. Capacity Step RNC 450/150 ................................................................141 14.1.2. Capacity Step RNC450/300 .................................................................143 14.1.3. Capacity Step RNC450/450 .................................................................145

14.2. New Plug-in Units ....................................................................................147 14.3. New mechanics and electromechanics ....................................................148

15. SW Architecture...............................................................................................149 15.1. RNC Service Blocks.................................................................................150 15.2. Exercise...................................................................................................159

Table of Figures:

Figure 1.........................................................................................................................10 Figure 2.........................................................................................................................11 Figure 3.........................................................................................................................12 Figure 4.........................................................................................................................13 Figure 5.........................................................................................................................14 Figure 6.........................................................................................................................15 Figure 7.........................................................................................................................16 Figure 8.........................................................................................................................17 Figure 9.........................................................................................................................18 Figure 10.......................................................................................................................19 Figure 11.......................................................................................................................20 Figure 12.......................................................................................................................21 Figure 13.......................................................................................................................22 Figure 14.......................................................................................................................23






Figure 15.......................................................................................................................24 Figure 16.......................................................................................................................25 Figure 17.......................................................................................................................26 Figure 18.......................................................................................................................27 Figure 19.......................................................................................................................28 Figure 20.......................................................................................................................29

Figure 21.......................................................................................................................30 Figure 22.......................................................................................................................31 Figure 23.......................................................................................................................32 Figure 24.......................................................................................................................33 Figure 25.......................................................................................................................34 Figure 26.......................................................................................................................35 Figure 27.......................................................................................................................36 Figure 28.......................................................................................................................37 Figure 29.......................................................................................................................38 Figure 30.......................................................................................................................39 Figure 31.......................................................................................................................40 Figure 32.......................................................................................................................41 Figure 33.......................................................................................................................42 Figure 34.......................................................................................................................43 Figure 35.......................................................................................................................44 Figure 36.......................................................................................................................45 Figure 37.......................................................................................................................46 Figure 38.......................................................................................................................47 Figure 39.......................................................................................................................48 Figure 40.......................................................................................................................49 Figure 41.......................................................................................................................50 Figure 42.......................................................................................................................51 Figure 43.......................................................................................................................52 Figure 44.......................................................................................................................53 Figure 45.......................................................................................................................54 Figure 46.......................................................................................................................55 Figure 47.......................................................................................................................56 Figure 48.......................................................................................................................56 Figure 49.......................................................................................................................57 Figure 50.......................................................................................................................58 Figure 51.......................................................................................................................59 Figure 52.......................................................................................................................60 Figure 53.......................................................................................................................61 Figure 54.......................................................................................................................62 Figure 55.......................................................................................................................63 Figure 56.......................................................................................................................64 Figure 57.......................................................................................................................65 Figure 58.......................................................................................................................65 Figure 59.......................................................................................................................66 Figure 60.......................................................................................................................67 Figure 61.......................................................................................................................68 Figure 62.......................................................................................................................69 Figure 63.......................................................................................................................70 Figure 64.......................................................................................................................71






Figure 65.......................................................................................................................72 Figure 66.......................................................................................................................73 Figure 67.......................................................................................................................74 Figure 68.......................................................................................................................75 Figure 69.......................................................................................................................75 Figure 70.......................................................................................................................76

Figure 71.......................................................................................................................77 Figure 72.......................................................................................................................78 Figure 73.......................................................................................................................79 Figure 74.......................................................................................................................80 Figure 75.......................................................................................................................80 Figure 76.......................................................................................................................81 Figure 77.......................................................................................................................82 Figure 78.......................................................................................................................82 Figure 79.......................................................................................................................83 Figure 80.......................................................................................................................84 Figure 81.......................................................................................................................85 Figure 82.......................................................................................................................86 Figure 83.......................................................................................................................87 Figure 84.......................................................................................................................87 Figure 85.......................................................................................................................88 Figure 86.......................................................................................................................89 Figure 87.......................................................................................................................90 Figure 88.......................................................................................................................90 Figure 89.......................................................................................................................91 Figure 90.......................................................................................................................92 Figure 91.......................................................................................................................93 Figure 92.......................................................................................................................93 Figure 93.......................................................................................................................94 Figure 94.......................................................................................................................95 Figure 95.......................................................................................................................95 Figure 96.......................................................................................................................96 Figure 97.......................................................................................................................97 Figure 98.......................................................................................................................98 Figure 99.......................................................................................................................99 Figure 100.....................................................................................................................99 Figure 101...................................................................................................................100 Figure 102...................................................................................................................101 Figure 103...................................................................................................................102 Figure 105...................................................................................................................104 Figure 106...................................................................................................................104 Figure 107...................................................................................................................105 Figure 108...................................................................................................................106 Figure 109...................................................................................................................106 Figure 110...................................................................................................................107 Figure 111...................................................................................................................108 Figure 112...................................................................................................................109 Figure 113...................................................................................................................110 Figure 114...................................................................................................................111 Figure 115...................................................................................................................111






Figure 116...................................................................................................................112 Figure 117...................................................................................................................113 Figure 118...................................................................................................................113 Figure 119...................................................................................................................114 Figure 120...................................................................................................................115 Figure 121...................................................................................................................116

Figure 122...................................................................................................................117 Figure 123...................................................................................................................118 Figure 124...................................................................................................................119 Figure 125...................................................................................................................120 Figure 126...................................................................................................................121 Figure 127...................................................................................................................122 Figure 128...................................................................................................................123 Figure 129...................................................................................................................124 Figure 130...................................................................................................................125 Figure 131...................................................................................................................126 Figure 132...................................................................................................................127 Figure 133...................................................................................................................128 Figure 134...................................................................................................................129 Figure 135...................................................................................................................130 Figure 136...................................................................................................................130 Figure 137...................................................................................................................131 Figure 138...................................................................................................................132 Figure 139...................................................................................................................133 Figure 140...................................................................................................................134 Figure 141...................................................................................................................135 Figure 142...................................................................................................................136 Figure 143...................................................................................................................137 Figure 144...................................................................................................................138 Figure 145...................................................................................................................139 Figure 146...................................................................................................................139 Figure 147...................................................................................................................140 Figure 148...................................................................................................................141 Figure 149...................................................................................................................142 Figure 150...................................................................................................................143 Figure 151...................................................................................................................144 Figure 152...................................................................................................................145 Figure 153...................................................................................................................146 Figure 154...................................................................................................................147 Figure 155...................................................................................................................148 Figure 156...................................................................................................................149 Figure 157...................................................................................................................150 Figure 158...................................................................................................................150 Figure 159...................................................................................................................151 Figure 160...................................................................................................................152 Figure 161...................................................................................................................153 Figure 162...................................................................................................................154 Figure 163...................................................................................................................155 Figure 164...................................................................................................................156 Figure 165...................................................................................................................157






Figure 166...................................................................................................................158 Figure 167...................................................................................................................159 Figure 168...................................................................................................................159






1. Nokia RNC Architecture

Figure 1

This module includes• Mandatory part (pages 9-130)

Objectives• Identify and list all the components of RNC, and know which redundancy is used foreach of them, and in which subrack they are located• Describe the functions of each component• List the characteristics of SFU, MXU, OMU, NEMU, NIP1, NIS1, GTPU, DMCU and

A2SU• From an end-to-end point of view, describe how an RNC handles both circuit- andpacket-switched data.• Know to which units a certain plug-in-unit can belong.• Explain how alarms, power and synchronization are handled in RNC.

• Explain reverse multiplexing for IMA• Name the interfaces implemented in the RNC

Learning time 3-6 hours

The weight of this module in the assessment is 35%

2. Data Flow in the RNC

The architecture of the RNC is modular, consisting of anumber of interconnected functional units.

In the data flow examples below, functional units willbe introduced in a step-by-step fashion. Not allfunctional units of the RNC are covered in theseexamples. However, the complete architecture of theRNC will be presented on the following page.






It is recommended that you first follow the data flow examples below as an introductionto the architecture, then study the details on the following pages, and finally return to thispage in order to get a general view of the whole picture.

2.1. Data flow in the control pane

2.1.1. Permanent Signalling Links

Permanent signalling links carry RANAP signalling messages over the Iu interfacebetween the RNC and core network elements, NBAP messages over the Iub interfacebetween the RNC and base transceiver stations, or RNSAP messages over the Iurinterface between two RNCs.

Permanent signalling links also carry the ALCAP signalling that is used for handling AAL2 connections.

Let us next see how - for example - an incoming NBAP message is routed within the

RNC.

Figure 2

The NBAP message arrives over the Iub interface at a network interface unit in the RNC.

If the Iub interface is based on PDH technology, the interface unit is called NIP1.






Figure 3

The signalling message is next sent to an ATM multiplexing unit (MXU), whichmultiplexes this signal together with ATM signals from other functional units in order to

obtain a high-speed ATM stream of 622 Mbit/s.

This ATM stream is then fed to the ATM switching fabric (SFU), where the ATM cellscontaining our signalling message are routed to the correct destination - in this caseanother multiplexing unit (MXU) behind which the destination unit is located.






Figure 4

The signalling message is sent to the signalling unit - called ICSU (Interface Control andSignalling Unit) - where the NBAP signalling protocol is terminated and the signalling

message is processed.






Figure 5

Signalling messages sent from the RNC to the BTS travel in the reverse order.

As we have seen - and shall see in further examples - all internal communication withinthe RNC is routed via the ATM switching fabric (SFU).

The signals are usually routed through multiplexers, except when they are carried viaSDH network interface units (NIS1). In a typical RAN scenario, the Iub interface is basedon PDH, whereas the Iur and Iu interfaces are based on SDH technology.






Figure 6

2.1.2. Common Control Channels

In the next example, we show how a signalling message received via an uplink Random Access Channel (RACH) is processed in the RNC.

The message is transmitted from the user equipment, traverses the base transceiverstation and arrives at the RNC via a PDH network interface unit (NIP1).






Figure 7

Since the signalling data between the RNC and user equipment is always carried over AAL2 connections, it must first be demultiplexed in an AAL2 switching unit - denoted A2SU.

The demultiplexing is illustrated in the figure insert on the right.






Figure 8

Next, the signalling data is sent to a signal processing unit - called DMCU (Data andMacro Diversity Combining Unit) - where some protocol processing is carried out.

To be more specific, the following protocols are terminated in this functional unit:

• Frame Protocol (FP)

• Medium Access Control (MAC)

• Radio Link Control (RLC).






Figure 9

Finally, the actual signalling message - most probably an RRC message - is sent to the

signalling unit where it is processed.






Figure 10

Signalling messages transmitted via a downlink Forward Access Channel (FACH) areprocessed in a similar way - naturally in the reverse order.






Figure 11

In the signal processing unit (DMCU), our signalling data is packed into an RLC frame -into a MAC frame - into a Frame Protocol frame - and is sent to the AAL2 switching unit(A2SU).






Figure 12

In the AAL2 switching unit (A2SU), our signalling data is multiplexed with other data -see the insert in the figure - and is sent via the network interface unit and the basestation to the user equipment.






Figure 13

2.1.3. Dedicated Control Channels

In the case of a dedicated control channel, it is possible that the signalling data is carriedbetween the RNC and user equipment via two or more radio links in parallel - note that inour example one link is via the Iur interface.






Figure 14

Regarding the link via the Iub interface, the signalling data is routed to a signalprocessing unit (DMCU) - as shown previously.

The signalling data received via the Iur interface must be routed to the same signal

processing unit (DMCU) - also in this case via an AAL2 switching unit (A2SU). Weassume that the Iur interface is an SDH interface.






Figure 15

Both branches undergo Frame Protocol processing in the signal processing unit(DMCU), after which macrodiversity combining is performed and there is some furtherMAC and RLC protocol processing.

Macrodiversity combining means that the signal with the highest quality is selected andsent to the signalling unit (ICSU) for further processing.






Figure 16

2.1.4 Summary

In summary, we have examined the flow of signalling data in the RNC, including the

following cases:• flow over a permanent signalling link

• flow in an uplink RACH

• flow in a downlink FACH

• flow over a DCCH in soft handover.

During the data flow animation, we have introduced the following functional units: NIP1,NIS1, MXU, SFU, A2SU, DMCU and ICSU.






Figure 17

2.2. Data flow in the user pane

2.2.1. User data between UE and CS-CN

In this example, we examine the data flow in the user plane, starting with circuit switcheduser data.

Let us assume that the user data is carried between the user equipment and the RNCvia two radio links in parallel - note that in our example one link is via the Iur interface.






Figure 18

Regarding the link via the Iub interface, the user data is routed to a signal processingunit (DMCU) via an AAL2 switching unit (A2SU).

The user data received via the Iur interface must be routed to the same signalprocessing unit (DMCU) - also in this case via an AAL2 switching unit (A2SU). We haveassumed that the Iur interface is an SDH interface.






Figure 19

Both branches undergo Frame Protocol processing in the signal processing unit(DMCU), after which macrodiversity combining is performed and the selected signalundergoes some further MAC and RLC protocol processing.

One important task of the MAC protocol layer is decryption of the encrypted user data.This is a processing intensive task that only the signal processing unit (DMCU) iscapable of performing.






Figure 20

After macrodiversity combining in the signal processing unit (DMCU), the signal with thehighest quality is selected and sent - via an AAL2 switching unit (A2SU) where AAL2layer multiplexing is performed - and via an SDH-based network interfacing unit (NIS1) -

over the Iu-CS interface towards the Mobile Switching Center.






Figure 21

In the downlink direction, the data flow is in the reverse order.

In the signal processing unit (DMCU), the signal is encrypted and sent with some outerloop power control information via the parallel radio links to the user equipment.






Figure 22

2.2.2. User data between UE and PS-CN

In the case of packet user data transport over a dedicated channel - as shown in thefigure - the processing is identical to the processing of circuit-switched user data, only inthis case we have assumed that both branches are via the Iub interface.

However, after macrodiversity combining and decrypting in the signal processing unit(DMCU), the packet data is sent to a new functional unit - called GTPU (GPRSTunnelling Protocol Unit) - instead of an A2SU unit.






Figure 23

The GTPU performs some IP and UDP protocol processing and guides the packet data

into the correct GTP tunnel, after which it is sent via an SDH network interface to theSGSN.

In the downlink direction, the processing is performed in the reverse order.






Figure 24

Small amounts of packet user data can be carried between the RNC and UE over aForward Access Channel (FACH) or Random Access Channel (RACH) instead of over aDedicated Channel (DCH).

Since these channels do not support soft handover, there is only one radio link betweenthe UE and RNC.

The user data is processed in two separate signal processing units (DMCU), due tospecific reasons related to the MAC protocol layer.






Figure 25

2.2.3. Summary

In summary, we have examined the flow of user data in the RNC, including the followingcases:

• circuit switched user data

• packet user data over DCH

• packet user data over FACH / RACH.

During the data flow animation, we have introduced one additional functional unit:GTPU.






Figure 26

3. RNC architecture overview

Now that you are familiar with some data flow scenarios in the RNC, let us examine thearchitecture of the RNC in more detail.

The RNC consists of one or two cabinets, depending on the capacity requirements asexplained on the page "RNC Capacity Evolution".

A cabinet contains four subracks, where each subrack contains a number of plug-inunits. However, the modular architecture of the RNC is best explained in terms offunctional units instead of plug-in units.

The functional units of the RNC are shortly introduced one at a time in the animation

below, and will be explained in more detail on the following pages.








Figure 28

3.1.2. ICSU

The Interface Control and Signaling Unit (ICSU) is responsible for handling the signalingover the Iu, Iub, and Iur interfaces. This functional unit also participates in distributedradio resource management related tasks of the RNC (handover control, admissioncontrol, load control and packet scheduling).

Plug-in units:CCP10 for RNC196CCP18-A for RNC450Memory size: 2 GBRedundancy: N+1

This functional unit is explained in more detail on page "4/16 Computing Units".






Figure 29

3.1.3. RRMU

The Radio Resource Management Unit (RRMU) performs centralised radio resourcemanagement and call management related tasks of the RNC.

Plug-in units:CCP10 for RNC196CCP18-A for RNC450Memory size: 2 GBRedundancy: 2N







Figure 30

3.1.4. RSMU

The Resource and Switch Management Unit (RSMU) is responsible for centralisedresource management tasks within the RNC such as connection control, ATM circuithunting, and management of DSP resources. It also performs call connection functionsas requested by interface control and signalling units (ICSU).








Figure 31

3.1.5. GTPU

The GPRS Tunneling Protocol Unit (GTPU) performs RNC related user plane functionsat the Iu-PS interface, such as handling the GTP-U, UDP and IP protocols.

Plug-in units:CCP10 for RNC196CCP18-A for RNC450Memory size: 2 GBRedundancy: SN+









Figure 33

3.1.7. OMU

The Operation and Maintenance Unit (OMU) performs basic system maintenancefunctions, such as hardware configuration, processing of alarm signals and centralrecovery functions.








Figure 34

3.1.8. WDU for OMU

The Hard Disk Unit (WDU) serves as a non-volatile memory for program code and data.Duplicated hard disk units are connected to and controlled by the OMU.

Plug-in units:HDS-A for RNC196HDS-B for RNC450Redundancy: 2N







Figure 35

3.1.9. FDU

The magneto-optical disk drive (FDU) controlled by the OMU is primarily used as aninterim storage device for facilitating temporary service operations.

Plug-in units:MDS-A for RNC196Removed from RNC450Redundancy: None







Figure 36

3.1.10. SFU

The ATM Switching Fabric Unit (SFU) handles - in conjunction with the multiplexer units- the entire internal communication of the RNC. When two or more functional unitscommunicate with each other, the signals are carried in ATM cells via the SFU whichroutes these cells to the correct destination.

Plug-in unit:SF10Redundancy: 2N

This functional unit is explained in more detail on page "6/16 Switching & MultiplexingUnits".






Figure 37

3.1.11. MXU

ATM Multiplexer Units (MXU) are required for connecting functional units with low tointermediate traffic capacity to the SFU. This is necessary for the effective utilisation ofthe high switching fabric interface capacity of the SFU (622 Mbit/s per port).

Plug-in unit:MX622-DRedundancy: 2N







Figure 38

3.1.12. A2SU

The AAL2 Switching Unit (A2SU) performs packet multiplexing and demultiplexing at the AAL2 level. AAL2 guarantees efficient transport of information with limited transfer delaywithin the radio access network.

Plug-in units: AL2S-B for RNC196 AL2S-D for RNC450Redundancy: SN+







Figure 39

3.1.13. NIS1 / NIS1P

The network interface unit NIS1 provides four optical SDH STM-1 interfaces, eachcarrying a bit rate of 155 Mbit/s.

Plug-in unit:NI4S1-BRedundancy is organised through appropriate routing (in the case of NIS1), or applied atthe plug-in unit level using the MSP 1+1 protection scheme (in the case of NIS1P).

This functional unit is explained in more detail on page "7/16 Physical Interfaces /Network Interface Units".






Figure 40

3.1.14. NIP1

The network interface unit NIP1 provides 16 PDH interfaces, each carrying a bit rate of1.5 Mbit/s (that is the T1 or JT1 option) or 2 Mbit/s (in the case of the E1 option). Theseunits also support the Inverse Multiplexing for ATM (IMA) function.

Plug-in unit:NI16P1ARedundancy is organised through appropriate routing.

This functional unit is explained in more detail on page "7/16 Physical Interfaces /Network Interface Units".






Figure 41

3.1.15. TBU

The Timing and Hardware Management Bus Unit (TBU) is responsible for networkelement synchronisation, timing signal distribution, and the transfer of messages overthe Hardware Management System (HMS) bus.

Plug-in units:TSS3 (red units)TBUF (green units)Redundancy: 2N

This functional unit is explained in more detail on page "8/16 Timing and HardwareManagement (TBU)".






Figure 42

3.1.16. EHU

The purpose of the External Hardware Alarm Unit (EHU) is to receive external alarmsand to send this information over the Hardware Management System (HMS) bus to thealarm handler of the OMU.

Plug-in unit:EHATRedundancy: None

This functional unit is explained in more detail on page "9/16 External Alarm Units".






Figure 43

3.1.17. NEMU

The Network Element Management Unit (NEMU) is a computer unit that provides anopen and standard computing platform for applications which do not have strict real-timerequirements.

Plug-in units:MCPC2 or MCPC2-A for RNC196MCP18-B for RNC450Memory size: 4 GBRedundancy: None

This functional unit is explained in more detail on page "10/16 Element Management".






Figure 44

3.1.18. WDU for NEMU

The Hard Disk Unit (WDU) serves as a non-volatile memory for program code and data.Duplicated hard disk units are connected to and controlled by the NEMU.

Plug-in units:HDS-A for RNC196HDS-B for RNC450Memory size: 2 GBRedundancy: 2N

This functional unit is explained in more detail on page "10/16 Element Management".








Figure 46

3.1.20. Subrack Power Distribution

Each subrack contains a plug-in unit for distributing the power within the subrack.

The type of plug-in unit depends on which type of cabinet is used and how much poweris needed.

Plug-in units:PD20 for RNC196PD30 for RNC450

This unit is explained in more detail on page "11/16 Mechanics and Power Supply".






Figure 47

3.2. Exercise

Figure 48






4. Computing Units

In the RNC, various computing functions are implemented on generic CCP10 or CCP18-

A control computer plug-in units.

The CCP10 for RNC196 and CCP18-A for RNC450 can be configured to provide thefollowing functional units:

• Interface Control and Signalling Unit (ICSU)

• Radio Resource Management Unit (RRMU)

• Resource and Switch Management Unit (RSMU)

• GPRS Tunnelling Protocol Unit (GTPU)

• Operation and Maintenance Unit (OMU).

Figure 49

4.1. ICSU

4.1.1. Interface Control and Signalling Unit (ICSU)

The signalling unit takes care of the NBAP signalling over the Iub interface, the RNSAPsignalling over the Iur interface, the RANAP signalling over the Iu interface, the RRC






signalling between the RNC and UE, and the ALCAP signalling that is used for handling AAL2 connections.

In addition, the signalling unit terminates, monitors and - in case of failure - recovers theSignalling ATM Adaptation Layer (SAAL) signalling links in the control plane.

Figure 50

In addition to the sending and receiving of signalling messages, the signalling unitparticipates in various distributed radio resource management tasks in the RNC.

These tasks are related to admission control, handover control, load control, packetscheduling, the management of radio resources, and the management of transportresources.






Figure 51

4.1.2. Radio Resource Management Unit (RRMU)

The RRMU performs central radio resource management and call management relatedtasks of the RNC.

Firstly, it maintains centralised information for each user connection, for instance all theidentifiers of the processes in the control computers for a particular user.

Secondly, the RRMU unit distributes paging messages.

Finally, it supports the OMU during the recovery from an ICSU failure.








Figure 53

4.1.4. GPRS Tunnelling Protocol Unit (GTPU)

The GTPU performs user plane functions related to the Iu-PS interface towards theSGSN. The two main functions are:

• Routing of the packet data to or from the SGSN through the correct GTP-U

tunnel• processing of the UDP and IP protocols used in the transport network layer






Figure 54

4.1.5. Operation and Maintenance Unit (OMU)

The OMU handles all the crucial higher-level system maintenance functions in the RNC,such as hardware configuration management, HMS supervision and the associatedcentralised recovery functions.

In the event of a fault, it automatically activates appropriate recovery and diagnosticsprocedures within the RNC.

The OMU is also responsible for the maintenance of the radio network configuration andstorage of radio network data.






Figure 55

The OMU serves as an interface between the Network Element Management Unit(NEMU) and the other functional units in the RNC. In addition, the OMU provides thefollowing interfaces:

•

A duplicated Small Computer System Interface (SCSI) for connecting massmemory devices

• A Service Terminal Interface for support of debugger terminals

• Duplicated Hardware Management System (HMS) interfaces.






Figure 56

A duplicated hard disk unit (WDU) and a non-redundant magneto-optical disk drive(FDU) are connected to the OMU via the SCSI interface.

The hard disk unit serves as a non-volatile memory for program code and data.

The magneto-optical disk drive is primarily used as an interim storage device..






Figure 57

4.1.6. Exercise

Figure 58






5. Signal Processing Unit

The Data and Macro Diversity Combining Unit (DMCU) performs RNC-related user andcontrol plane functions requiring digital signal processing capability.

Each DMCU contains several state-of-the-art Digital Signal Processors (DSPs) andgeneral purpose Reduced Instruction Set Computer (RISC) processors.

DMCU units and their processors can be freely and dynamically allocated to variousprocessing tasks in the RNC - with one exception: when several dedicated channelsexist to a certain user equipment, the signal processing related to these channels mustbe performed in the same DMCU.

Figure 59

5.1. DMCU tasks

5.1.1. Macrodiversity Combining

The macrodiversity combining point in the Serving RNC is located in a DMCU unit.

Macrodiversity combining means that the user data is carried over several radio links inparallel from the user equipment to the Serving RNC, and the data from the radio link






with the best quality is selected by the Serving RNC for further transport to the corenetwork.

In the downlink direction, the user data received from the core network is distributed tothe corresponding radio links.

Figure 60

5.1.2. Uplink Outer Loop Power Control

During uplink outer loop power control, the RNC monitors the quality of the uplink signalafter macrodiversity combining.

If the signal quality is not sufficient, the RNC commands the base station to increase theTarget Signal-to-Interference Ratio (SIR) value used for inner-loop - or fast - powercontrol.

If the signal quality is unnecessarily high, this means that radio resources are wastedand the RNC commands the base station to decrease the Target SIR value.






Figure 61

5.1.3. Downlink Outer Loop Power Control

Downlink outer loop power control is handled by the user equipment instead of the signalprocessing unit (DMCU).






Figure 62

5.1.4. Frame Protocol

In addition to carrying the higher layer information between the Serving RNC and thebase station - possibly via a Drift RNC as shown in the figure - the Frame Protocol (FP)supports the handling of macrodiversity combining and outer loop power control.

In the RNC, it is the DMCU unit that takes care of the frame protocol processing..






Figure 63

5.1.5. MAC Protocol Processing

The Medium Access Control protocol is used between the user equipment and ServingRNC for mapping between logical channels and transport channels, and for selecting anappropriate transport format for each transport channel.






Figure 64

5.1.6. Ciphering

One important MAC function is ciphering.

In GSM, circuit switched user data is ciphered between the mobile station and the BTS,whereas GPRS packet data is ciphered between the mobile station and the ServingGPRS Support Node.

In UMTS, by contrast, the ciphered connection is always between the user equipmentand the Serving RNC.






Figure 65

5.1.7. RLC Protocol Processing

The Radio Link Control (RLC) protocol is used between the user equipment and ServingRNC for adapting both the user data and RRC signalling to the MAC layer.

In particular, RLC handles automatic repeat request (ARQ) functions for the IP traffic.






Figure 66

5.1.8. PDCP Protocol Processing

Regarding the packet traffic, the Packet Data Convergence Protocol (PDCP) on top ofRLC compresses the redundant information contained in the IP packet headers.






Figure 67

5.1.9. DMCU Tasks: Summary

In summary, DMCU units have to take care of several protocols, heavy processing andimportant radio resource management tasks.






Figure 68

5.2. Exercise

Figure 69






6. Switching & Multiplexing Units

Switching and multiplexing in the RNC is based on ATM technology.

ATM provides the required capacity and flexibility to support the various types of traffic in

the radio access network as well as all the internal communications within the RNC itself.

There are three functional units involved in ATM switching and multiplexing:

• The ATM Switching Fabric Unit (SFU)

• The ATM Multiplexer Unit (MXU)

• The AAL2 Switching Unit (A2SU).

Figure 70

6.1. ATM Switching Fabric Unit (SFU)

6.1.1. Switching Fabric Unit (SFU)

The 2N redundant ATM Switching Fabric Unit handles - together with multiplexer units -the entire internal communication of the RNC.

The switching is non-blocking at the ATM connection level. This means that as long asthe required input and output capacity is available, ATM connections can always beestablished through the fabric.






Figure 71

The SFU offers 16 duplicated switching ports, each capable of handling a data rate of622 Mbit/s, and operates at a switching speed of 10 Gbit/s.

Functional units of the RNC are connected to the SFU via multiplexer units, with oneexception - SDH network interface units.






Figure 72

The SFU supports point-to-point and point-to-multipoint connection topologies, as well asdifferentiated handling of various ATM service categories.






Figure 73

6.2. ATM Multiplexer Unit (MXU)

6.2.1. Multiplexer Unit (MXU)

The 2N redundant ATM Multiplexer Unit (MXU) combines traffic from up to 18 tributaryunits and sends the ATM cells to the ATM switching fabric - or vice versa.

The RNC contains an even number of Multiplexer Units, depending on the configuredcapacity. Each unit is interfaced to both Switching Fabric Units for reasons of reliability.






Figure 74

The Multiplexer Unit is based on UTOPIA (Universal Test and Operation PhysicalInterface) level 2 multiplexing functions.

The MXU also carries out ATM layer processing functions, including address reduction,performance monitoring, traffic policing, buffer management, statistics handling, andsome Operation and Maintenance functions.

Figure 75

6.3. AAL2 Switching Unit (A2SU)

6.3.1. AAL2 Switching Unit (A2SU)

The ATM Adaptation Layer 2 (AAL2) offers multiplexing of data from different sources -carried within separate so-called Mini Packets within the RNC - into the payload of a






single ATM cell, provides efficient transport of the data over the external interface, anddemultiplexes the data at the destination.

Figure 76

The ATM Adaptation Layer 2 Switching Unit (A2SU) performs AAL2 multiplexing asshown in the previous animation, and naturally also performs demultiplexing of thereceived AAL2 data.






Figure 77

6.4. Exercise

Figure 78






7. Physical Interfaces / Network Interface Units

The physical interface units NIS1 and NIP1 map the ATM cell streams to the framestructure of two widely used transmission systems, namely the Synchronous DigitalHierarchy (SDH) and the Plesiochronous Digital Hierarchy (PDH).

The NIS1 unit contains four optical SDH STM-1 interfaces, each carrying a bit rate of155 Mbit/s.

The NIP1 unit contains 16 electrical PDH interfaces at 1.5 or 2 Mbit/s. It also supportsthe so-called Inverse Multiplexing for ATM (IMA) function that enables the flexiblegrouping of physical links into logical IMA groups.

Figure 79

7.1. SDH interfaces

7.1.1. Physical Interface Unit NIS1

The physical interface unit NIS1 contains four optical SDH STM-1 interfaces of 155Mbit/s each.






The STM-1 optical interface characteristics are shown in the table on the right.

Interfaces of this type are intended to be used primarily at the Iu and Iur interfaces..

Figure 80

7.1.2. SDH Functions

The NIS1 unit provides interfaces to the optical fibers, and performs SDH relatedfunctions such as line coding and timing recovery in the receiver.






Figure 81

7.1.3. ATM-layer Functions

The NIS1 unit also takes care of ATM cell-related functions, such as generation andverification of the cell header error check bits, and finding the cell boundaries at thereceiving end of the transmission link.

Furthermore, the unit performs advanced traffic management functions in the ATM layer,such as congestion control, traffic shaping, and buffer management.






Figure 82

7.1.4. O&M Functions

Finally, the NIS1 unit handles physical layer maintenance signals and transmissionperformance monitoring, and provides a clock reference output.






Figure 83

7.1.5. ATM traffic over STM-1

The bit rate of the STM-1 signal is 155.520 Mbit/s. The payload of the STM-1 frame hasa slightly smaller transmission capacity of about 150 Mbit/s. The STM-1 payloadcontains a VC-4 Virtual Container into which the ATM cell stream is mapped as shown inthe figure.

Figure 84






7.1.6. Multiplex Section Protection (MSP)

The functional unit NIS1P offers bidirectional MSP1+1 redundancy at the plug-in unitlevel. In this scheme, the traffic over the SDH interface is transmitted along two links atthe same time. At the receiving end, the traffic is selected from either of these links.

Switching in case of a failure is non-revertive, in other words the traffic is not switchedback to the original working unit even after the failure has been repaired.

Figure 85

7.2. PDH Interfaces

7.2.1. Physical Interface Unit NIP1

The physical interface unit NIP1 contains 16 PDH interfaces - at 1.5 or 2 Mbit/s each -for carrying ATM traffic by means of a technique called Inverse Multiplexing for ATM(IMA).

ATM over PDH transport is intended to be used primarily at the Iub interface.






Figure 86

7.2.2. Inverse Multiplexing for ATM (IMA)

Inverse Multiplexing for ATM - or IMA - means that several physical PDH channels canbe combined to carry an ATM cell sequence at a higher bit rate than 1.5 or 2 Mbit/s.

IMA ensures that the multiplexed ATM cells are delivered in sequence.

The PDH interfaces of an IMA Group must all be on the same interface unit.






Figure 87

7.3. Exercise

Figure 88

8. Timing and Hardware Management (TBU)The Timing and Hardware Management Bus Units (TBU) are responsible for thesynchronization of the network element, reliable distribution of the timing signal, andreliable transport of alarm messages in the Hardware Management System (HMS).

There are two plug-in units in each subrack as well as a duplicated timing distributionbus and a duplicated HMS bus spanning all subracks of the network element.






Figure 89

8.1. Synchronisation

The Timing and Hardware Management Bus Units take care of the synchronization ofthe network element and the distribution of the timing signal to the plug-in units.

A duplicated synchronization unit (TSS3) receives the reference timing signal from theexternal network, and delivers this timing signal via a duplicated timing distribution bus tobuffering units (TBUF) in each subrack, which in turn distribute the timing signal via theback plane to the plug-in units in the subrack.






Figure 90

8.2. Hardware Management and Supervision

Another important role of the Timing and Hardware Management Bus Units is to offerbridging functions necessary for RNC’s internal Hardware Management System (HMS).

The HMS provides reliable message forwarding for fault and configuration managementof the plug-in units and auxiliary devices such as fan trays and power supplies. Inaddition, it offers a redundant messaging bus for controlling the states of the functionalunits and supervising the general health of the network element (for instance:temperature, door locking and alarms).






Figure 91

8.3. Exercise

Figure 92






9. External Alarm Units

The RNC can be equipped with a non-redundant External Hardware Alarm Unit (EHU)that sends alarm indications to the Operation and Maintenance Unit (OMU) via theHardware Management System (HMS) bus.

In addition, the EHU provides outputs for driving an external alarm lamp panel (EXAU) inthe telecommunication site room.

Figure 93

9.1. EHU

9.1.1. External Hardware Alarm Unit (EHU)

The purpose of the External Hardware Alarm Unit (EHU) is to receive external alarmsand to carry indications of these alarms within messages via the Hardware ManagementSystem (HMS) bus to the external alarm handler located in the Operation andMaintenance Unit (OMU).

A second function of this unit is to drive the alarm lamps integrated in the RNC cabinet,as well as the fault-indication lamp panel in the optional External Alarm Unit (EXAU)located in the telecommunication site room.






Figure 94

Connections to external devices are done via the CPSAL-B cabling panel located in therear side of the RNAC cabinet or via the CPAL panel located in the optional cablingcabinet CEXT.

Figure 95






9.2. Exercise

Figure 96

10. Element Management

NEMU provides an open computing platform for applications performing variousfunctions related to the external O&M interfaces – for instance, NEMU post-processesperformance management data and provides assistance for SW upgrades. In practice,NEMU functionality is divided between four plug-in units:

• MCP18-B plug-in unit

• ESA24 plug-in unit

• Two HDS-B plug-in units

In addition, a variety of peripheral devices can be attached to NEMU, for example,printer, monitor, keyboard, mouse and external SCSI-devices – such as external harddisks).






Figure 97

10.1. NEMU Tasks

The NEMU provides an MMI interface for the local NEMU client which may perform local

operations using MML commands.

Furthermore, NEMU receives network element level alarms from the RNC and BTSs,and transfers those to the NMS and to the local client over the CORBA based NWI3interface.

Third important task of the NEMU is to post-process statistical data from the RNC andBTSs and transmit it further to the NetAct.






Figure 98

10.2. NEMU in a nutshell

MCP18-B is a Management Computer with Pentium processor designed for NEMU usein RNC. It is equipped with an Intel Pentium-M processor with 4 GBytes of non-changeable memory.

The MCP18-B provides four USB ports, for instance to be used by external storagedevices.

In RNC it hosts the Operating System Microsoft Windows Server 2000 (MCP18-B alsosupports Redhat Linux).






Figure 99

10.3. Exercise

Figure 100

11. Mechanics and Power Supply

The Nokia RNC is built on Nokia's IPA2800 switching platform, which in turn is based on

M2000 mechanics, the ETSI 300 119-4 standard and IEC 917 series standards formetric dimensioning of electronic equipment. Special attention is paid to fulfilling therelevant parts of network element building system (NEBS) level 3 requirements.

Particular attention has also been paid to thermal resistance.






Figure 101

11.1. Basic Concepts

The RNC consists of either one or two cabinets. A cabinet contains four subracks. Eachsubrack contains 19 slots of 25 mm width for carrying various kinds of plug-in units.

For the RNC196 the cabinet type is IC186-B and for the RNC450 the cabinet type isEC216. The main difference is the cabinet height. The cabinet height for RNC196 is 1.8meters, compared with 2.1 meters for the RNC450.

There is also an external cabling cabinet available that can be placed next to the maincabinet. You can examine the dimensions of these items with your mouse pointer.






Figure 102

The IC 186-B cabinet hosts two types of subracks, called SRA1-B and SRA2-B. Thesubrack type SRA1-B is only used in the first two positions in cabinet A (RNAC). All otherpositions use the subrack type SRA2-B. The only difference between the two types ofsubracks is that SRA2-B integrates more of the subrack's internal cabling in its backpanel (between, for instance, the multiplexing units and tributary units).

The new EC216 cabinet is equipped with a new subrack (SRA3).

The subracks are designed according to the ETS 300119-4 standard.






Figure 103

11.2. Power Supply

The power distribution subsystem distributes the -48V power from the rectifiers orbatteries to the equipment inside the network element cabinets.

This subsystem consists of two cabinet power distribution panels (80A CPD80-B forIC186-B and 120A CPD120 for EC216) at the top of each cabinet, subrack power

distribution plug-in units (20A PD20 for IC186-B and 30A PD30 for EC216) located at thecenter of each subrack, and the associated cabling.

The subrack power distribution plug-in unit also controls the cooling equipment of its ownsubrack on the basis of messages sent by the operation and maintenance unit (OMU).






Figure 104

11.3. ROHS

The Nokia RNC complies with the European Union RoHS Directive 2002/95/EC on theRestriction of the use of certain Hazardous Substances in electrical and electronicequipment.

The directive applies to the use of lead, mercury, cadmium, hexavalent chromium,polybrominated biphenyls (PBB), and polybrominated diphenyl ethers (PBDE).

It applies to the new telecom equipment put on the market after 1 July 2006.






Figure 105

11.4. Exercise

Figure 106






12. Reliability and Redundancy Principles

The RNC is designed to be fault tolerant, and great attention is paid to the reliability ofoperation.

All centralised functions of the system are protected in order to guarantee highavailability of the system. Hardware and software of the system are constantlysupervised. When a defect is detected in an active functional unit, a spare unit isactivated by an automatic recovery function.

The types of redundancy encountered in the RNC are: Duplication, Replacement, Loadsharing, and No redundancy.

Figure 107

12.1. Reliability of the RNC

12.1.1. Reliability of the RNC

The RNC is designed to meet the availability requirements of the ITU-T.

The design objectives shown on the following slides have been adopted to ensure thatthe availability of the RNC is high, as experienced by the subscriber.






Figure 108

12.1.2. High availability

Simplicity and the speed of maintenance procedures are the prerequisites for theavailability of the RNC.

The maintenance is improved by the modularity of the equipment, automatic faultdetection procedures and elimination of downtime by using a hot standby redundancy forcrucial functions of the RNC.

Figure 109






12.1.3. Maintenance design objectives

The following general design objectives have been established for the maintenance of

the RNC:• Mean active repair time less than half an hour

• Fault localisation with the accuracy of one plug-in unit for 70 % of the faults

• Fault localisation with the accuracy of four plug-in units for 95 % of the faults.

Figure 110

12.2. Redundancy Principles

12.2.1. Four types of redundancy

The four types of redundancy encountered in the RNC are:

• 2N redundancy (duplication)

• N+1 redundancy (replacement)

• SN+ redundancy (load sharing)

•

No redundancy at all.

Let us examine these redundancy principles in more detail.






Figure 111

12.2.2. 2N Redundancy (Duplication)

Duplication means that there is one spare unit allocated for each active unit.

The spare unit is in hot standby, which in practice means that the software in the unitpair is kept synchronised. As a result, switchover - in other words taking the spare unitinto use in fault situations - is very fast.






Figure 112

12.2.3. N+1 Redundancy (Replacement)

If the reliability requirements are less strict, one or more spare units may be allocated for

a larger group of functional units.

The spare unit is in cold standby, which in practice means that synchronisation of thespare unit - also called warming - is performed as a part of the switchover procedure. Asa result, switchover is rather slow to execute.






Figure 113

12.2.4. SN+ Redundancy (Load Sharing)

If a number of functional units act as a resource pool, there is no need to allocate spareunits.

The number of units in the pool is selected so that there is some extra capacity. If a unitis disabled because of a fault, the whole group can still perform its designated functions.






Figure 114

12.2.5. No Redundancy

Some functional units have no redundancy at all.

A failure in such a unit is not critical, even if it takes some time to replace the unit.

Figure 115






12.3. Redundancy of Functional Units

12.3.1. Redundancy of Functional Units

The type of redundancy for each functional unit in the RNC is shown in the table on the

right.

The power supply redundancy solution is presented on the next slide.

Figure 116

12.3.2. Power Supply Redundancy

Redundancy for the power distribution (PD) plug-in units has been achieved by providingeach functional unit - crucial for the operation of the RNC - with one or more redundantunits in a separate subrack in accordance with the SN+, N+1 or 2N principle.

In RNAC subracks 1 and 2, the power supply to the units has true 2N redundancy.

However, the aggregate capacity of the other units may be reduced somewhat if there isa failure that completely eliminates one of the PD units.






Figure 117

12.4. Exercise

Figure 118






13. RNC Capacity Steps

The capacity of the RNC can be increased in seven capacity steps. In this way, theNokia RNC can be adapted to the varying capacity demands of different radio accessnetwork implementations.

The minimum RNC configuration consists of one fully equipped RNC cabinet, calledRNAC. The maximum RNC configuration consists of two fully equipped RNC cabinets,RNAC and RNBC.

The two subracks at the top of RNAC contain important functional units with 2Nredundancy that are not found elsewhere.

Figure 119

13.1. Capacity Steps in the RNC

13.1.1. Capacity Step 1

This is the minimum RNC configuration. The cabinet RNAC is fully equipped. A secondcabinet is not required.






Subracks 1 and 2 contain the 2N redundant functional units SFU, RRMU, RSMU andOMU, as well as two NIS1 units, the NEMU, EHU (optional), hard disk units, floppy diskunit, 2N redundant TSS3 plug-in units, and an Ethernet switch.

The number and placement of these units does not depend on the capacity of the RNC.

Figure 120

Subracks 1 to 4 contain the following functional units as shown in the figure:6 ATMmultiplexing units (MXU)

• 7 signalling units (ICSU)

• 3 AAL2 switching units (A2SU)

• 12 signal processing units (DMCU)

• 2 GPRS tunneling units (GTPU)

• 0-4 PDH network interface units (NIP1)

• 2 additional NIS1 units (optional).

The four subracks also contain the following plug-in units:

• 6 timing units (TBUF)

• 4 power distribution units (PD20).






Figure 121

The minimum RNC configuration offers the capacity in the figure on the right. Thiscapacity can be allocated to any traffic mix of voice and data.






Figure 122

The table on the right shows the number of functional units and plug-in units included inthis capacity step.






Figure 123


In capacity step 2, the cabinet RNBC contains all four subracks - with subrack 1 fullyequipped.

Subracks 2, 3 and 4 in the cabinet RNBC contain no plug-in units, not even PD20 orTBUF units. These subracks are only equipped with cover plates.






Figure 124

In addition to the power distribution unit (PD20) and the two timing signal distributionunits (TBUF), the new subrack contains the following functional units:

• 2 ATM multiplexing units (MXU)• 3 signalling units (ICSU)

• 1 AAL2 switching unit (A2SU)

• 8 signal processing units (DMCU)

• 1 GPRS tunneling unit (GTPU)

• 2 optional PDH network interface units (NIP1).






Figure 125

The capacity figures of capacity step 2 are shown in the figure on the right.






Figure 126







Figure 127


In capacity step 3, the second subrack in cabinet RNBC is equipped in the same way asthe first subrack.

The capacity figures of capacity step 3 are shown in the figure.






Figure 128







Figure 129


In capacity step 4, the third subrack in cabinet RNBC is equipped in the same way as thefirst and second subrack.

The capacity figures of capacity step 4 are shown in the figure.






Figure 130







Figure 131


In capacity step 5, both cabinets are fully equipped.






Figure 132







Figure 133

13.2. Upgrade RNC196 to higher capacity

The upgrade of RNC196 to RN2.2 level involves two new optional capacity extensionsteps. These capacity steps extend the RNC capacity from 196 to either 300 or 450Mbits/s.

The five RN2.1 capacity steps consisted of plug-in unit additions, whereas the RNC196capacity steps 6 (RNC196/300) and 7 (RNC196/450) require RNC configuration changesand plug-in unit changes.

The table on the right shows the Iub capacities and the number of STM-1 and E1/T1interfaces supported per capacity step. Note that the RNC196 capacity steps 6 and 7require most of the existing PDH cards to be removed.






Figure 134

13.2.1 RNC196 capacity Steps 6 (RNC196/300) and 7 (RNC196/450)

There are two possible capacity upgrades: from 196 Mbit/s to 300 Mbit/s and from 196Mbit/s to 450 Mbit/s. Both of these capacity upgrades require cabling and configurationchanges to the Network Element.

The old electromechanical set supports both capacity upgrades. The differences lie in

the plug-in unit requirement levels. In the RNC196/300 configuration, the CPUs are atleast CCP10, and in the RNC196/450 configuration the CPUs are all at least CCP18-A.






Figure 135

13.2.2 RNC196 capacity Step 6 (RNC196/300)

The Iub capacity of the RNC can be expanded to 300 Mbits/s by making the followingchanges in the RNC configuration together with the required modifications to the internalcabling:

• The Floppy Disk Unit is removed.The following Plug-in Units need to be added:2 AL2S-D for A2SU

• 2 CCP18-A for GTPU

• 2 MX622-D for MXU

• 3 CCP18-A for ICSUThe following Plug-in units need to be replaced:

• 2 CCP18-A for OMU

• 2 HDS-B for WDU

All RRMU, RSMU, ICSU and GTPU must be at least CCP10.

All other MXU must be MX622-D and all DMCU must be CDSP-C.

Figure 136







Figure 137

13.2.3 RNC196 capacity step 7 (RNC196/450)

The Iub capacity of the RNC can be expanded to 450 Mbits/s by making similar changesin the RNC configuration and cabling as with the RNC196/300 upgrade.

The following Plug-in units need to be added:

• 2 ALSD-2 for A2SU

• 2 CCP18-A for GTPU

• 2 MX622-D for MXU

•

3 CCP18-A for ICSUThe following Plug-in units need to be replaced:2 CCP18-A for RRMU

• 2 CCP18-A for RSMU

• 2 CCP18-A for OMU

• 2 HDS-B for WDU

All other A2SU must be AL2S-D, all other MXU must be MX622-D, all DMCU must beCDSP-C, and all ICSU and GTPU must be CCP18-A.






Figure 138







Figure 139

13.3. Optional Upgrade

In addition to capacity upgrades it is also possible to upgrade the RNC196 to enablecertain new features or functionalities.






Figure 140

The AAL2 switching capacity can be increased without any cabling changes.

This is achieved by replacing old AL2S-B plug-in units with the new AL2S-D plug-inunits.

The increased AAL2 connectivity is presented in this table.






Figure 141

The support for the control plane A-GPS requires the following hardware changes in theRNC:

• RRMU upgrade• Duplicated ESA24

In addition, cabling changes and site switches are required to enable the redundantWAN connection from RNC to the A-GPS Server or SAS.






Figure 142

It is also possible to add two pairs of STM-1/OC-3 interface units NIS1P in theRNC196/196 configuration.

This upgrade supports two new NIS1P pairs to RNAC subracks 1 and 2.






Figure 143

The NEMU plug-in Unit can be upgraded to MCP18-B.

Because the older MCPC2 and MCPC2-A plug-in units provide only one SCSI bus, bothNEMU hard disks were connected with the same bus.

The MCP18-B is equipped with two SCSI buses. Therefore, separated SCSI busesbetween the NEMU and its hard disks can now be provided.






Figure 144

13.3. RNC HSDPA connectivity and capacity

The table on the right shows the maximum Iub capacity, connectivity and interfaces forthe HSDPA feature.






Figure 145

13.4. Exercise

Figure 146

14. RNC450 RN2.2 New Delivery

One of the main functional changes between the RN2.1 and RN2.2 is the increase of theIub throughput from 196 Mbit/s to 450 Mbit/s. This requires certain Plug-in Unit changesand additions.






The RN2.2 introduces a new cabinet (EC216) and new electromechanics. These arechanged for two main reasons:

First, the power feeding and cabinet cooling capacity is increased by about 50%.

Secondly, the power feeding system is improved to take future release upgrades intoaccount.

Figure 147

14.1. Capacity Steps

The capacity of the RN2.2 can be increased in three capacity steps: RNC450 capacitystep 150, RNC450 capacity step 300 and RNC450 capacity step 450

.The smallest configuration consists of one cabinet containing the main parts of theentire node as well as the first capacity step plug-in units.

The second configuration requires an additional second cabinet and second capacitystep plug-in units to be added.

The third configuration requires two cabinets with a full capacity of configured plug-inunits to provide maximum throughput.






Figure 148

14.1.1. Capacity Step RNC 450/150

The RNC 450 capacity step 150 implements the minimum capacity and consists of afully equipped RNAC cabinet.

The maximum number of WCDMA Base Stations attached with RNC450 capacity step150 is 200 and the maximum number of carriers is 600. The carriers are identified withthe scrambling code and frequency.

The total AAL2UP capacity is 1000 Mbit/s.






Figure 149

The table on the right shows the number of functional units and plug-in units included in

the first capacity step.






Figure 150

14.1.2. Capacity Step RNC450/300

The RNC450 capacity step 300 consists of a fully equipped RNAC cabinet and cabinetmechanics for an RNBC cabinet.

This includes all 4 subracks for an RNBC cabinet, all needed plug-in unit types forsubrack numbers 1 and 2 of an RNBC cabinet and cover plates for subracks numbers 3

and 4 of an RNBC cabinet.

Note that RNC450 capacity step 300 does not include any plug-in units for subracks 3and 4 in RNBC, not even PD30s or TBUFs. Cover plates conceal the slots of subracks 3and 4.






Figure 151


the first two capacity steps.






Figure 152

14.1.3. Capacity Step RNC450/450

The RNC450 capacity step 450 consists of all needed plug-in unit types in RNAC andRNBC cabinets.

You can find a summary of the new plug-in units by clicking on the “New Plug-in Units"label below.






Figure 153


this capacity step.






Figure 154

14.2. New Plug-in Units

The following four new plug-in Units have been updated when compared with releaseRN2.1:

The CCP18-A plug-in unit is used by all computer units. It is equipped with 2GB of RAMand has a USB 1.1 interface.

The AL2S-D plug-in unit is used for all AAL2 Switching Units in order to achieve higher AAL2UP connectivity (max 2 Gbit/s)

The MCP18-B plug-in unit is used for NEMU. It provides two SCSI bus interfaces for thehard disks and is equipped with 4GB of RAM.

The HDS-B variant is used for enabling two hard disk units to be filled in a single slot (forOMU and NEMU).








Figure 156

15. SW ArchitectureIn the RNC, each control computer has common system software. This uniform systemsoftware provides a standard, easy-to-use operating environment for the applicationsoftware.

The uniform operating environment facilitates the development and maintenance of theapplication software and helps the user to understand the operation of the software.

The high level software architecture of the Nokia RNC is illustrated on the right.






Figure 157

15.1. RNC Service Blocks

The RNC application forms a single system block - or SYB. The RNC SYB comprisesseveral service blocks (SEBs) that take care of set of closely related functions - such asRRM (Radio Resource Management) Services.

Each service block contains a variety of program blocks (PRB).

Figure 158

AGSSEB provides the IPA2800 part of the performance management functionality inRNC. The PM feature includes measurement and online monitoring statistics for theoperator to observe the status and functioning of the radio access network.






Online monitoring measures the events in real time and they can be viewed online in theEM system, whilst periodic measurements are collected after specified intervalsdetermined by the defined time schedule. determined by the defined time schedule.

Figure 159

IUUSEB handles the multiprotocol packet data user plane between the Iu-PS interfaceand RLC layer inside the RNC. The key functions of IUUSEB are:

• Iu-PS GTP-tunnel management and PDCP management in co-ordination withL3TSEB

• User data PDU buffering (DL) and header compression (DL) and decompression(UL)

• UL and DL multiprotocol user data PDU delivery between IP based Iu-PS andRLC






Figure 160

The L3 telecom (L3TSEB) is responsible for handling the layer 3 signalling protocolsover the Iub, Uu, Iur and Iu interfaces. The protocols used are NBAP, RRC, RNSAP andRANAP.

L3TSEB controls the signalling resources, routes the paging messages inside the RNC,controls the connections to terminals and takes care of the resource releasing inside theRNC in case of unit restart and overload situation.

L3TSEB also takes care of system information scheduling and segmentation.






Figure 161

P2PSEB provides parts of the Layer 1 and Layer 2 protocol services for telecom dataand signalling message transfer. It also handles lower level Outer Loop Power Controlfunctions.






Figure 162

Radio Network Administration Service Block (RNASEB) provides the following mainservices

• Radio Network Configuration Management

• Radio Network Connection Configuration Management

• Radio Network Configuration Plan Management

•

Radio Network Reset and Initialisation• Radio Network Recovery

• Iub O&M Mediation

• Radio Network Alarm System






Figure 163

The Radio Resource Management Service Block is responsible for the Base StationRadio Resource Management and Handover Control. Base Station Radio ResourceManagement includes:

• Admission Control

• Packet Scheduling

•

Code Management

Handover Control includes control functions for the "soft" and "hard" handovers. (See thefunctionality module for more information about handover types)






Figure 164

The Resources For Application Level Service Block (R4ASEB) includes TransportResource Manager and Binding Id Functions. It handles the transport resourcereservation, modification and releasing in applications level in the RNC. It provides aninterface between radio related applications (e.g. MS Connection Controller and RadioResource Controller) and transport related applications provided by the switchingplatform. R4ASEB also allocates Binding IDs for the Iur control plane signalling entityRNSAP. It also provides a Binding ID identification service to AAL type 2 signalling inDRNC.






Figure 165

L1 and L2 Signal Processing Service Block (SP5SEB) consists of DSP software. TheDigital Signal Processors and SP5SEB are used in computational intensive applications.For instance, this program block decodes and encodes ciphered RLC traffic andprovides MAC layer functions for dedicated channels. In the Layer 1, functions such as

macrodiversity combining, outer loop power control and frame protocol functions belongto responsibilities of SP5SEB.






Figure 166

DLFSEB provides a service interface and management functions for UE locationestimate calculations and assistance data requests. It also contains algorithms forcalculating cell-id based location estimates. PSFSEB provides LCS algorithms forcalculating CI+RTT and A-GPS method based location estimates. It is also responsiblefor transactions between the RNC and A-GPS Server/SAS. P4LSEB providesparameters related to LCS functionality and access interface parameters.





Figure 167

Nokia Rnc Architecture

Documents