3G Transmission Dimension Ing Process

8/10/2019 3G Transmission Dimension Ing Process

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1 NOKIA TRS_Presentation_Smart / 01-07-2005/OSP-Manila Company Confidential

3G Transmission DimensioningProcess

June 2005

Charles Kao


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TRS Planning Requirement & Dimensioning


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Network Dimensioning Process Flowchart

Input fromcustomer

RFDimensioning

TransmissionDimensioning

IPDimensioning

NetworkDimensioning

done


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Trs Network Dimensioning Process Flowchart

Input from RFIub

dimensioningRNC

dimensioning

Quantity of

E1, STM-1 etcrequired

Iu-CS, Iu-PS, Iur

dimensioningTrs dimensioningassumptions



Network Dimensioning Process

CS/PS Core NetworkDimensioning

The Customer Requirements and/or Nokia assumptions

Node B Dimensioning

RAN Dimensioning

RNC location

Iub traffic

IuCS/PS traffic

3G subscriber growth forecast and distribution per region 3G Packet Data, Circuit Switched Data & Voice traffic/sub

CS Core Traffic Model Coverage Requirements

# of Core sites

QoS requirements

Number &configuration ofNode B

# of sites

configuration of sites

e.g. 1+1+1/SRC/MHA

# of Hardware channels

# andconfigurationof RNC

RAN InerfaceCapacityrequirements

# and configuration of coreelements

user plane/control planerequirements

# & type of Iub & Iu

links # of interface cards

# of AXC

Link Capacity

Transmission Dimensioning



RAN dimensioning output

Interfaces

Iub Link Capacity (Node B < = > RNC)

Iur Link Capacity (RNC < = > RNC)

Iu Link Capacity

Circuit Switched (RNC < = > MSC)

Packet Switched (RNC < = > SGSN)

Equipment

Number of RNCs



RAN & Core dimensioning Steps

INPUTS

Traffic

Hypothesis/Assumptions

INTERFACES

Iub_Voice

Iub_PS

Iub_CS_data Total_Iub

RNCIu_CS

Iu_PS

Circuit Core Dimensioning

Iur

Packet Core Dimensioning

3G-MSC

DNS, CG, ....

xGSN

MGW



RAN Protocol Stacks

IP

AAL5

PHY

UDP

LLC/SNAP

GTP-U

ATM

PHY

ATM

AAL2

FP

PDCP

UDP

IP

Link

Layer

PHY

GTP

IP

AAL5

PHY

UDP

LLC/SNAP

GTP-U

ATM

UDP

IP

Link

Layer

PHY

GTP

AAL2

PHY

ATM

WCDMAL1

FP

WCDMAL1

PDCP

E.g.,IPv4, IPv6

PHY

E.g.,IPv4, IPv6

GnIuIubUuGGSN

3G-RNC

Node B

UEGi

RLC-U

MAC

RLC-U

MAC

Each layer in protocol stack will add additional bits to the original payload and depending of the interface,

different overheads are used. Below there are presented protocol stacks for both CS and PS traffic.In Iu interface there can be distinguished two different types of traffic,IuCS (Iu-Circuit Switched, data and speech) for connections towards MGW/MSC andIu-PS (Iu-Packet Switched) for 3G-SGSN.

AAL2

PHY

ATM

PHY

ATM

AAL2

FP

PHY

AAL2

PHY

ATM

LinkLayer

PHY

AAL2

PHY

ATM

WCDMAL1

FP

WCDMAL1

E.g.,Vocoder

PHY

PSTN/

N-ISDN

AIuIubUu

IWU

RNC

Node B

UE

E

Iu-CS UPIu-CS UP

E.g.,Vocoder

LinkLayer

/lawPCM,UDI,etc.

/lawPCM,UDI,etc.

MSC

RLC-U

MAC

RLC-U

MAC


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Circuit Switched Traffic

Circuit Switched Traffic

Circuit switched traffic can be divided in two types, Voice and Data.

Most cases 12.2 kbps (AMR mode 0) for voice is used. This mode correspondsEnhanced FR in GSM network.

RAN 1 and 1.5 supports the following Voice and Circuit switched service rates whichcorresponds to the following bitrates:

AMR Mode 0 1 2 3 4 5 6 7

Rate (kbps) 12.20 10.20 7.95 7.40 6.70 5.90 5.15 4.75

RAN 1 and RAN 1.5 supports the following service rates for circuit switched data.

Rate kbps Comment

9.6 Base Rate 114.4 Base Rate 2

19.2 2 x 9.6 kbps

28.8 2 x 14.4 kbps

38.4 4 x 9.6 kbps

57.6 4 x 14.4 kbps

64 UDI (Unrestricted Digital Information)


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Packet Switched Traffic

Packet Switched Traffic

RAN 1 and 1.5 supports the following service rates or combination of them for packetswitched data.

Rate 0 1 2 3 4 5 6 7 8

Rate kbps 384 320 256 128 64 32 16 8 0


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RAN calculation related protocols & overheads, 1

Air Interface Protocols Assumptions (L1, MAC, RLC,PDCP), Re-Transmission & Buffering

L1 OH includes pilot symbols, TFCI field, closed loop PC bits ...etc,this is not used by RNC L1, they are generated inside the BS and so this

overhead is not included.The L1 functions inside the RNC are macro-diversity combining(MDC) & Outer-looppower control

L2 OH includes MAC & RLC. For CS traffic the RLC is transparent. For PS traffic the

RLC takes care of re-transmission in case of errors, and consequently there is a L2OH. The assumption is that L2 re-transmission is 10% (Quality of the radio link, BLER) 15% headroom to avoid infinite buffering.

For PS data this will result 1/0.79 extra overhead :

(1 + 10% L2 reTRX)( 1 + 15% headroom) = 1/0.79 = 26.5% OH.


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Frame ProtocolsFrame protocols are applied to transfer user data and the necessary control informationbetween the Serving RNC (SRNC) and the BS. They are characterized by a frame structureconsisting of the payload, that contains the data (typically one or more MAC PDUs) and aheader/trailer with control information (used for synchronization, power control, CRC bits, etc).Three different Frame Protocols are specified in UTRAN:

Iub CCH FP (3GPP TS 25.435)

RAN: DCH FP (3GPP TS 25.427)

Iur CCH FP (3GPP TS 25.425)

They are independent but have a similar structure and coding of the frames.

For Voice (Active and Silent Mode), FP frames (including OH) are sent every TTI(TransmissionTime Interval) regardless of the activity (Active or Silent) of the user. During theSilent mode, SID (Silence Descriptor) otherwise known as Comfort Noise frames, are sent every8th frame of the FP frames (including OH) thus bits are generated even during the silent mode.


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Iu-User Plane ProtocolsFrame Protocols are terminated in the RNC and replaced by Iu-UP (User Plane) protocols in the Iu-CS andIu-PS interface. User Plane protocols either operates on Transparentor Support modes. Transparent modesare used for transmission of GTP-PDUs and no headers at the head of the Iu-UP PDU are defined. Supported

modes are applicable during e.g. the AMR based speech connection thus headers are generated on thismode of operation. The percentage of header generated on support mode is comparable to the FP headersthus, traffic calculation in Voice & CS data for Iu-CS interface is similar to Iub calculation.

ATM Protocols

ATM protocols overhead consists of two-layers :

ATM Adaptation Layer 2 (AAL2) - is used to adapt the air-interface protocols into ATM cells.

ATM Layer consists of 5 bytes of overheads that adapts AAL PDUs to ATM cells

PDH/SDH layer ATM cells are then mapped into physical transmission channels implemented usingPDH/SDH technologies.


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Soft-Handover FactorSoft Hadover Factor is assumed to be 40%.

35% of the Mobiles are connected to two or more Base Stations at the same time.

30% of the Mobiles are in two way SHOs5% of the Mobiles are in three way SHOs

This value is coming from the IS-95 experience and from our simulations. There is trade offbetween SHO gain and capacity and this is somehow of our target in order to get some gain

without waste of our capacity.

In other words, if one RNC manages 100 Voice calls, then it must have 140 (100*1.4) physicalchannels (as compared to a GSM BSC managing 100 calls, having 100 time slots).

For transmission networks this factor is only relevant in the Iub interface because the RNC

terminates all connections and selects the connections with the best quality.

For The Customer case, SHO of 30% was adopted


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Voice Activity Factor

The system uses DTX (Discontinuous Transmission), so when there is no speech, the systemstops transmitting data (on L1). Unless the operator gives the Voice Activity factor, we assumeactivity factor as from 50% to 69%. (67% used in The Customer case)


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Signalling Overheads

Signaling has to be considered for each of the interfaces. Different assumptions are to be defined for Iub, Iur and Iuinterfaces.

In Iub interface this is normally includes

L3 signalling DCH (Dedicated channels) overhead

Mobile signalling overhead in common channel states

CC, MM.

NBAP-C

NBAP-D

AAL2 signalling

Since there is no practical network results available yet, 10% of user-plane traffic can be assumed (based on GSMexperience and modelling) as signalling.

For the Iu interface, signalling overhead is considered as 1% of user-plane traffic.

This is a temporary value as this is also based on GSM experience (the A-interface). This includes AAL2 Signallingand RANAP signaling for Iu-CS and GTP signalling and RANAP signaling for Iu-PS interface.

For Iur interface, 2- 4 % of the user traffic is assumed to be signaling.. This is includes AAL2 signaling and RNSAP.

This is again based on studies made inside Nokia.


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Each different service require different overheadEach different service require different overhead

Overhead vsTraffic Classes?

Voice services Activity Service bit rate L1 bit rate Bit rate incl. FP Bit rate below ATM

kbps kbps kbps 12.76%

RT12.2 (AMR) UL active 12.2 12.2 15.6 18.9

silent 0 0 2.8 4.5

RT12.2 (AMR) DL active 12.2 12.2 14.8 18.0

silent 0 0 0 0.0

RT Services Activity service bit rate L1 bit rate Bit rate incl. FP Bit rate below ATM


RT64 active 64 64 65 78.7

NRT Services service bit rate L1 bit rate Bit rate incl. FP Bit rate below ATM


NRT64 UL/DL 64 67.2 71.2 85.7

NRT128 DL 128 134.4 138.4 166.9

NRT256 DL 256 268.8 272.8 329.3NRT256 DL 320 336 340 410.4

NRT384 DL 384 403.2 407.2 491.6

Different OH for Different Traffic Classes


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AAL2 OH

Voice services Activity Service bit rate L1 bit rate TTI Data/frame FP OH Total /frame Bit rate incl. FP AAL2 PDU AAL2 OH Bits to ATM Bit rate below AAL2

kbps kbps ms bit octet bit kbps # octet bits kbps

RT12.2 (AMR) UL active 12.2 12.2 20 244 7 312 15.6 1 3 336 16.8

silent 0 0 20 0 7 56 2.8 1 3 80 4.0

RT12.2 (AMR) DL active 12.2 12.2 20 244 5 296 14.8 1 3 320 16.0silent 0 0 20 0 0 0 0 0 3 0 0.0

RT Services Activity service bit rate L1 bit rate Frame period Data/frame FP OH Total /frame Bit rate incl. FP AAL2 PDU AAL2 OH Bits to ATM Bit rate below AAL2


RT14.4 active 14.4 14.4 40 576 5 616 15.4 2 3 664 16.6

RT28.8 active 28.8 28.8 40 1152 5 1192 29.8 4 3 1288 32.2

RT32 active 32 32 40 1280 5 1320 33 4 3 1416 35.4

RT33.6 active 33.6 33.6 40 1344 5 1384 34.6 4 3 1480 37.0RT56.7 active 56.7 56.7 40 2268 5 2308 57.7 7 3 2476 61.9

RT64 active 64 64 40 2560 5 2600 65 8 3 2792 69.8

NRT Services service bit rate L1 bit rate Frame period Data/frame FP OH Total /frame Bit rate incl. FP AAL2 PDU AAL2 OH Bits to ATM Bit rate below AAL2


NRT8 UL/DL 8 9.6 10 96 5 136 13.6 1 3 160 16.0

NRT16 UL/DL 16 17.6 10 176 5 216 21.6 1 3 240 24.0NRT32 UL/DL 32 33.6 10 336 5 376 37.6 2 3 424 42.4

NRT64 UL/DL 64 67.2 10 672 5 712 71.2 2 3 760 76.0

NRT128 DL 128 134.4 10 1344 5 1384 138.4 4 3 1480 148.0

NRT256 DL 256 268.8 10 2688 5 2728 272.8 8 3 2920 292.0

NRT256 DL 320 336 10 3360 5 3400 340 10 3 3640 364.0

NRT384 DL 384 403.2 10 4032 5 4072 407.2 12 3 4360 436.0


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RAN Dimensioning Inputs

In general, the following inputs are required for dimensioning:

Total number of Subscribers (Subs)

Number of Subscribers for Voice

Number of Subscribers for CSD/ Service class Number of Subscribers for PSD/ Service class

Number of Base Stations

Average Voice traffic / busy hour Average CSD traffic / busy hour

Average PSD traffic / busy hour

Uu interface blocking

Voice Activity Factor for Voice (VAF=50-69%)


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Iub Interface Dimensioning

Iub

BS

BS

BS

Iur

Iub

Iub

RNC

RNC

Iub is the interface between Base Station and Radio Network Controller

Iub Traffic is the total of both Circuit Switched (Voice & data) and Packet Switched data


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I b Dimensioning CS Traffic


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Iub Dimensioning, CS Traffic

Input information

10 mErl/sub (Voice) 5 mErl/sub (CS data) Service rate 64kbit/s 500 subs/BTS SHO = 40%

VAF = 65% Iub sig. = 10%

7,5 Erl /BTS

14 ch's/BTS

SHO = 40%

Erlang B table (Traffic with 2% blocking)

20 ch's/BTS

Voice channels/BTS

10 mErl15 mErl

x 20 ch's = 14 ch's5 mErl

15 mErlx 20 ch's = 7 ch's

CS data channels/BTS

Iub Dimensioning CS Voice


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Iub Dimensioning, CS Voice

VAF = 65%

Average voice rate in ATM:18,9 kbit/s x 65 % + (4,5 kbit/s x 35%) = 13,86 kbit/s

Voice channel in Uu = 12,2 kbit/s

Voice channel, Active = 18,9 kbit/s Voice channel, Silent = 4,5 kbit/s

Voice in the ATM

VAF of 67% is used in The Customer case

Iub Dimensioning CS Traffic


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Iub Dimensioning, CS Traffic

14 ch's/BTS x 13,86 kbit/s/ch = 194,04 kbit/s/BTS 7 ch's/BTS x 64 kbit/s/ch = 448 kbit/s/BTS

Voice CS Data

ATM OH = 23%

551 kbit/s

Total CS traffic in Iub/BTS = (194,04 kbit/s + 551 kbit/s) + 10 % Iub sig. = 819,5 kbit/s

Iub Dimensioning (3/3) PS Data


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Iub Dimensioning (3/3), PS Data

Input : Traffic ( kbits) / cell / region

BS Config / region

Method : Bit rate (kbps) / BS

Output : PS Iub Bit rate (kbps) / BS

@ BH@ BH

Activity Factor 100%SHO factor 30%ATM OH (64k +33%, 128k +30%, 384k +28%)

L1 BufDelay OH 26.5%

For each service


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Iur Dimensioning

Iur interface is the traffic between two different RNCs. Eg for Soft Handover

Iub

RNC

RNC

RNC

Iur

Iur

I t d ti t I I t f


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Introduction to Iur Interface

MSC

IurRNC

BSBS

Iub

BS

RNC

BSBS BS

RNC

BSBS BS

Iu

Iur

MSCSGSN

IuIu

Iub Iub

Iur interface is needed for :

Transmitting and receiving the MS signal via two different BS which belong to twodifferent RNCs.

Signalling between the individual RNCs, (e.g. for HO establishments).


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RNC Dimensioning

Based on Nokia ATM Platform

Nokia RNC Dimensioning


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What need to be checked ?

Iub throughtput

Number of carriers

Number of BTS's

Nokia Radio Network Controller


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Nokia Radio Network Controller

Rel. 1.5 & 2: 48-196 Mbit/s Dynamic Traffic Capacity

1 2

3

4

5

RNC release 1.5 & 2Config.

Iub Mbit/s BTSs Carriers STM-1 E1

1 48 128 384 4*4 6*16

2 85 192 576 4*4 8*16

3 122 256 768 4*4 10*16

4 159 320 960 4*4 12*16

5 196 384 1152 4*4 14*16

Iub traffic capacity Interfaces



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Limitations:

Inputs:

RNC fill rate 90%

Circuit Switched Voice

Circuit Switched Data

Packet Switched Data

Iub Data Throughput Number of Carriers Number of Node Bs

Release 1.5

196 Mbps 1152 carriers 384 Node Bs

Voice Channels 16Kbps in RNC


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Voice Channels, 16Kbps in RNC

MGW

Voice Channel at 12.2 kbps or lesser

Voice Channel at 16 kbps

12.2 or lesser

Even lower bitrates requires as much processing capacity (user and control plane)Within RNC as a 16kbps channels.

In the Transmission it is taken as original bit rates.

ATM Overhead in RNC


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ATM Overhead in RNC

RNCNode B

ATM Transmission Medium

ATM OH added atNIU

ATM OH stripped offat the Interface unit

of RNC

ATM Overhead is considered only on the Transmission

The ATM OH is stripped off at the NIU of RNC

Hence traffic to RNC will not include ATM overhead.

Nokia RNC Dimensioning Principle


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Nokia RNC Dimensioning Principle

Check the number of carriers per RNC

Check the number of Node B per RNC

RNC nominal traffic capacity

Carriers to be connectedCarriers connectivity per RNC * Fillrate

Node B to be connectedNode B connectivity capacity per RNC * Fillrate

Total user traffic in the area

Voice erlangs* 16kbit/s

CS-data erlangs* data rate

PS-data volume(busy hour)

* SHO overhead * SHO overhead * SHO overhead

1)

Capacity Almost Independent of the Traffic Mix


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Iu Interface Dimensioning

RNC

MGW SGSN

CS

PS

Iu interface

Iu Dimensioning Flow


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Iu Dimensioning Flow

Voice ActivityFactor

(VAF=67%)

Voice CS Traffic@ 12.2 kbit.sData CS Traffic @ X kbit/s Data PS Traffic @ X kbit/s

ATM overhead (ATMOH)

@ X kbit/s

ATM overhead (ATMOH)

@ X kbit/s

ATM overhead(ATMOH) @

12.2 kbit/s

Iu-CS Capacity needed

Iu signalling (SigOH%) 1% Iu signalling (SigOH%) 1%

Iu-PS Capacity needed

Iu-CS Protocol Overheads


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Iu CS Protocol Overheads

The transmission overheads between RNC and MSC are similar to theoverheads of Voice and Circuit Switched traffic in Iub. Therefore thecalculation of Iu traffic from RNC to MGW/MSC is similar to Iub trafficcalculation. The only difference is that all subscribers under one RNC are

pooled together and the calculations are based on that.

SHO is not included because all connections are terminated at the RNC.

Iu-CS Interface Dimensioning


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Iu CS Interface Dimensioning

Input :

Method :

Output :

For each service (voice, CS 64kbps)

@ BH@ BH

Total Traffic (Erl) / RNC area

Erlang B (GOS- 0.1%)

# TCh / RNC area

Line rate (12.2kbps, 64kbps )Activity Factor for voice: 67%ATM OH (as in Iub)

Signalling overhead + 1%

Traffic ( Erl) / BS / region# BSs & Config / region

Bit rate (kbps) / clutter

Iu-PS Protocol Overheads


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Iu PS Protocol Overheads

Between RNC and 3G-SGSN transmission overheads are unique and their relative sizedepends strongly on the packet size that needs to be transmitted from RNC to 3G-SGSN.

The traffic comes from the mobile station to the RNC, then it is tunnelled through the3G-SGSN to destination (Internet, Intranet). This tunnelling requires GTP plus UDP

and IP (encapsulated) running on AAL5 ATM transmission media.

ATM AAL5 Encap IPv4 UDP GTP Data

User Data = 512 Bytes (TCP session)

AAL5 PDU = (512 + 8 Encap+20 IP+ 8 UDP+ 12 GTP)= 560 bytes

AAL5 PDU + trailer =(560+8) = 568AAL5 PDU + trailer + padding = Roundup (568/48) x 48

12 cells needed, 8 bytes of padding

Including ATM headers = Roundup (568/48) x 53 = 636

Total OH required = (636-512)/512= 24% OH

8 20 8 12 (Packet Length)

PHY

AAL5


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Max. 65535 Octets

Padding 0-47 octets

Trailer 8 octetsAAL 5 layer

ATM layer

48 Octets

ATM header 5 octets

PDU

Iu-PS Interface Dimensioning


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g

Input : Traffic ( kbits) / BS / region

# BSs & Config / region

Method :

Output : Bit rate (Mbps) / region

@ BH@ BH

ATM, AAL5, IP, UDP, GTP OH +24%

Signalling overhead +1%

Bit rate (kbps) / region

For packet sizeOf 512 bytes

Via ATM/AAL5

RNC --> SGSN

Transmission Lines Calculation in RAN


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When a needed amount of the physical connections (for example E1's or STM1s)are calculated it should be always noticed that only available payload part of theconnection can be used. It was specified in ATM Forum that TS 0 & TS 16 arenot to be used for ATM traffic. Thus

Table 1: SONET Multiplexing Hierarchy

ElectricalSignal

OpticalSignal

GrossRate

(Mbps)

User Rate(Mbps)

STS-1 OC-1 51.84 49.536

STS-3 OC-3 155.52 149.46

STS-12 OC-12 622.08 594.432

STS-48 OC-48 2488.32 2377.728

Possibility of Introducing AXCs


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50 Node B- DU

50 X 0.33 E1

50 Node B- DU

50 X 0.33 E1

80 Node B- U

80 Node B- U

80 X 0.44 E1

80 X 0.44 E1

RNC

AXC

AXC

AXC

AXC

1 X STM1

1 X STM1

1 X STM1

Config.

Iub Mbit/s BTS Carriers STM-1 E11 48 128 384 4*4 642 85 192 576 4*4 963 122 256 768 4*4 1284 159 320 960 4*4 1605 196 384 1152 4*4 192

Iub traffic capacity InterfacesMax. capacity in different configurations

Detailed Transmission requirement, NetAct Planner


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3G Transmission Dimension Ing Process

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