Mobile network strucure

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Ahmed Hussien Ali Gomaa Bebars Mobile: 01024614238

Mobile network Structure

Mobile network structure as show in GSM course

We will explain how to transmit call from MS (Mobile station) to another from Transmission view

Transmission

Transmission Method divided three steps

Access layer Backhaul layer

Core layer

From Site (BTS)HUB (in

most cases HUB locate at

TE (Telecom Egypt

Exchange)

Transport method from Site

to HUB:

1. Fiber

2. Microwave (there

are different

vendors support

Microwave

equipment like as

Ericsson-Huawei-

SIAE-NEC

3. DSL technology

From HUBMTX

MTX refer to place where MSC &

BSC & RNC&GMSC Locate

Transport method from Site to

HUB:

1. Multiplexing technology

(PDH System & SDH

technology)

2. IP Network (MPLS

Network)

Example of Nodes locates at HUB

& MTX:

1. DXX

2. ADM

3. PTN & Tellabs 86xx

From MTXMTX

When MSC or GMSC need connect

Transport method from Site to

HUB:

1. IP Network (MPLS)

Example of Nodes locates at MTX:

1. Routers

2. OSN or any device convert

Packet data to POS (Packet

over SDH) to transfer over

TE network that still use

SDH technology at

transport data

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Connection between BSC & MSC & GMSC and other nodes inside MTX connect between them by direct

cable back to back

If two nodes use different protocols we will use transport nodes and also connect by direct cable

TE Cloud

Inside MTX

Inside HUB

SDH Network B

ackhau

l layer

AC

Cess laye

r

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Plesiochronous Digital Hierarchy (PDH): it is old transmission method & use standard frame

E1 European system (32 Ts with rate 2.048 Mb/S)

T1 American System (24 Ts with Rate 1.53 Mb/Sec)

J1 Japan System (24 Ts with Rate 1.53 Mb/Sec)

Note: PDH still transport method used over access layer

When you Multiplex four E1 get E2 & after Multiplex four E2 get E3 & Multiplex E3 get E4 as

maximum rate in this techniques with rate 139 Mb/Sec

SDH (Synchronous Digital Hierarchy): new technology with Basic frame STM1 with Rate 155 Mb/Sec

we can get STM4 (four STM1) & STM16 (Four STM4) & STM64 (four STM16) with rate reach to 10

Gb/Sec

DSL (Digital Subscriber Line) this technology use to Modulate/Demodulate signal over traditional

telephone line

There are different types from DSL (ADSL-HDSL) at Mobile network we use HDSL where download 7

Upload with the same rate

ATM (Synchronous Transfer Mode): new technology use to transfer data & Video & Voice by use

concept cell switching where ATM use cell 53 byte (5 for Header & 48 for data) and use VC (Virtual

Circuit) & VP (Virtual Path) as addressing to route cell inside ATM network

IMA (Inverse Multiplex Technology) this technology use to convert ATM cell into PDH frame to transfer

ATM cell over network use another transport technology

For example:

ATM use BW assign with Mb/Sec, so if you want BW 8 Mb/Sec for ATM cells & we use MW links use

E1 frame to transfer data we will use IMA

MPLS (Multi protocol label Switching): its new technology use to transfer any transport technology

(E1 or FR or ATM) over packet switch network, MPLS actual transport method use now to transport data

at Backhaul network

E1:1

E1:2

E1:3

E1:4

ATM use BW 8 Mb/Sec IMA

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Access layer:

Most common technology used in this layer at Egypt MW links

Any MW links divided into two common parts:

1. ODU (Outdoor Units)

a. RAU (Radio Access Unit)

b. Horn antenna

c. Reflector

d. IF cable (Intermediate frequency cable) use to connect ODU & IDU (this cable Coaxial

cable)

2. IDU (indoor type): there are different types according to Vendor type

a. Ericsson: Mini link E – Traffic Node (TN) – Compact Node (CN) – High cap (HC)

b. Huawei: RTN (Radio Traffic Node)

c. SIAE : Access link compact (ALC PDH- ALC+2-ALC+2e)

d. NEC: Paso link – I Paso Link

Sites connect tin chain connection till reach to HUB MW then connect with Backhaul node with direct

cable

DSL: use DSLAM at HUB & Modem and we use Modem at site I will explain used of them in other part

Backhaul layer:

Use to multiplex all data come from different sites to transport them to MTX and there are different types

from Nodes use in this layer each of them according to transport technology used

1. DXX (Digital Drop Multiplexer): common vendor used in Egypt network Ericsson & use

Tellabs 81xx family. DXX use PDH transport technology and Maximum data transport E4

2. ADM (Add drop Multiplexer): also common vendor node used Ericsson & use Tellabs 64xx

family Nodes

3. Tellabs 86xx family new node from Ericsson use MPLS transport technology to transport data at

Backhaul layer (engineer at Egypt field called it BEP Node, where BEP is Backhaul evaluation

Project)

4. PTN (Packet Transport Node) 6900 series from Huawei use MPLS technology to transport

data

PTN & Tellabs 86xx connect with RNC (Ericsson) by direct ATM Ports

BSC (Ericsson) Connect with ADM then ADM Connect with PTN or Tellabs 86xx

BSCH & RNCH (Huawei) connect direct with PTN node