Concept of Pdh Multiplexing

Concept of PDH Multiplexing

1

• What is the need of

• Exploiting the media and the line

terminal equipment for optimum

capacity.

•

2

•

Types of multiplexing ?

– FDM

– TDM PDH

3

– TDM

– DWDM

SDH

• What is Frequency Division Multiplexing ?

• Prescribed Structure of FDM?

Stage of No. of Chls Frequency Range

PDH MULTIPLEXING

4

hierarchy

• Channel …… ……..1 1- 4 kHz

• Sub Group…………3 12 - 24 kHz

• Group…………….12 60 - 108 kHz

• Super Group………60 312-552khs

• Super Master Group……….900 Channel

(312-4028 Khz)

PDH MULTIPLEXING

5

(312-4028 Khz)

• Band for Microwave Radio Channel

2 x Super Master Group (900 Channel)

• Band for 4 Mhz coaxial cable 1 Super

Master Group (900 Channel)

• Band for 12 Mhz coaxial cable

PDH MULTIPLEXING

6

• Band for 12 Mhz coaxial cable

3 x Super Master Group (900 Channel) =

2700 Channel

• In TDM there are two type of

multiplexing

1. Plesiochronous Digital Hierarchy

7

2. Synchronous Digital Hierarchy

• What is DWDM ?

– DWDM means on each wavelength we can

transmit one transport digital structure.

8

transmit one transport digital structure.

• Prescribed PDH Hierarchies.

S. No. Order of Mux. Bit rates No. of Channels

PDH MULTIPLEXING

9

1. First Order 2048kbit/s 30

2. Second Order 8448kbit/s 120

3. Third Order 34368kbit/s 480

4. Fourth Order 139264kbit/s 1920

5. Fifth Order 565Mbit/s 7680

PDH MULTIPLEXING

410 2 200 208 208 4 204

1a 2a 3a 4a 1b 2b 3b 4b

4 4

1b 2b 3b 4b s1 s2 s3 s4

8.448 Mbit/s ; frame length 848 bit: 100.4 us ; ITU-T G.742

10

1 1 1 1 0 1 0 0 0 0 A N

1a 2a 3a 4a 1b 2b 3b 4b

A: Alarm Bit

N: National Spare Bit

: Stuffing Control Bit

S: Stuffing Bit

Frame sync signal

1 1 1 1 0 1 0 0 0 0 1 φ1 φ2 φ3 φ4x

y #2#1 #3

φ1 φ2 φ3 φ4 φ1 φ2 φ3 φ4

#49 #50

φ1 φ2 φ3 φ4 φ1 φ2 φ3 φ4SET 1

C1

C11 C12 C13 C14

#51 #52 #53 #54 #55 #101 #102

φ2 φ3 φ4 φ1 φ2 φ3 φ4SET 2

Details of 8.448 Mbit Frame Structure

11

C11 C12 C13 C14 φ2 φ3 φ4 φ1 φ2 φ3 φ4

C2

C21 C22 C23 C24

#103 #104 #105 #106 #107 #153 #154


C3

C31 C32 C33 C34

V #155 #156 #157 #158 #204 #205


• Standard Principles of Multiplexing ?

• It conforms interfaces as per ITU recommendation G.703

• Principle characteristic of Multiplexing or De-multiplexing as per ITU

PDH MULTIPLEXING

12

• Principle characteristic of Multiplexing or De-multiplexing as per ITU recommendation G.742

• Multiplexing method

bit by bit interleaving in tributary sequence

• Coding - HDB3

• Remote Station Alarm reception

• Local loop back

13

• Local loop back

• Remote Loop Back

Elastic

Memory at

2Mbit/s

Elastic

Memory

at 8Mbit/s

ENCODER

Concept of Local Loop Back

14

2Mbit/s at 8Mbit/s

DECODER

Concept of Remote Loop Back

Elastic

Memory at

2Mbit/s

Elastic

Memory

at 8Mbit/s

ENC.

Elastic

Memory at

2Mbit/s

Elastic

Memory

at 8Mbit/s

DEC.

15

DEC. ENC.

A Station B Station

410 2 372 380 380 4 378

1b 2b 3b 4b

4

1c 2c 3c 4c s1 s2 s3 s4

34.368 Mbit/s ; frame length 1536 bit; 44.7 us; ITU-T G.751

4

1a 2a 3a 4a

16

1 1 1 1 0 1 0 0 0 0 A N

1b 2b 3b 4b

A: Alarm Bit


: Stuffing Control Bit

S: Stuffing Bit

1a 2a 3a 4a

Frame sync signal

1 1 1 1 0 1 0 0 0 0 1 φ1 φ2 φ3 φ4x

y #2#1 #3

φ1 φ2 φ3 φ4 φ1 φ2 φ3 φ4

#92 #93

φ1 φ2 φ3 φ4 φ1 φ2 φ3 φ4SET 1

C1

C11 C12 C13 C14

#95 #96 #97 #98 #99 #184 #185


Details of 34.368Mbit Frame Structure

17

C11 C12 C13 C14 φ2 φ3 φ4 φ1 φ2 φ3 φ4

C2

C21 C22 C23 C24

#186 #187 #188 #189 #190 #281 #282


C3

C31 C32 C33 C34

V #283 #284 #285 #286 #----- #-----


Plesiochronous Hierarchies -

Frame Structures

139.264 Mbit/s; frame length 2928 bit; ITU-T G.751

12 4 472 484 484 4 48444 4 484 4 480 4

18

1 1 1 1 0 1 0 0 0 0 A N

1b 2b 3b 4b 1c 2c 3c 4c s1 s2 s3 s4

A: Alarm Bit


1a,b,c,d: Stuffing Control Bit

S: Stuffing Bit

1a 2a 3a 4a

N N

1b 2b 3b 4b 1b 2b 3b 4b

01

PARAMETERS BITS

ALLOCATION

SET

Frame alignment word : 111110100000

Alarm indication for far-end terminal

Bits reserved for national use

Bits coming from tributaries

from 1 to 12

13

from 14 to 16

from 17 to 488

Justification service bits

bits coming from tributaries

SET II to V

from 1 to 4

from 5 to 488

19

bits coming from tributaries from 5 to 488

SET VI

Justification service bits

Variable slots

bits coming from tributaries

from 1 to 4

from 5 to 8

from 9 to 488

Frame width

Bits per tributary per frame

Information bits per tributary

2928 bit

2928 : 4 = 732 bit

732 bit

• 2/8 Opti Mux.

• System Architecture as per (PUNCOM)

PDH MUXING

E

X

E

X2nd

2Mb/s 2Mb/sO/I O/I

20

X

C

H

A

N

G

E

2nd

Order

Mux/

Demux

8Mb

OLTE8Mb

OLTE

X

C

H

A

N

G

E

2nd

Order

Mux

2Mb/s

2Mb/s

2Mb/s

2Mb/s

2Mb/s

2Mb/s8Mb/s

O/W

8Mb/s

O/WPhone Phone

70 km (max)

2nd

Order

Mux/

Demux

Bit Rate : 8448kbps

Impedance : 75 Ohms

unbalanced

Line Code : HDB-3

Electrical Interface and Orderwire

21

Type of Order Wire : ADM

VF Band : 0.3 to 3.4 kHz

S/NQ : >24dB

Noise : Better than

-45Bm0p

Optical Interface

Bit Rate : 8.976 Mb/s

Optical Source : Laser

Center Wavelength : 1310 nm

Spectral Width : 4nm or less

Mean Launch Optical

Power : -2 to -5dbm

PDH MUXING

22

Power : -2 to -5dbm

Optical Receiver : PINFET

Receiver Sensitivity for : >-38dbm

BER 1 x 10E-10

Dynamic Range of Receiver : >20db

Receiver Overload : 0dbm

Type of Connector : FC - PC

• 2/34 Opti Mux.

• System Architecture as per (PUNCOM)

PDH MULTIPLEXING

E

X2/342Mb/sO/IE

X2Mb/s O/I

23

34Mb

OLTE

X

C

H

A

N

G

E

2/34

Mux

and

Dmux

2Mb/s

34Mb/s

O/WPhone

70 km (max)

X

C

H

A

N

G

E

2/34

Mux

and

Dmux

34Mb

OLTE

2Mb/s

34Mb/s

O/WPhone

(1)

(16)

(1)

(16)

34368kbit/s Interface (Specification as per HFCL make )

Bit Rate : 34368kbit/s

Impedance : 75 Ohms unbalanced

Tolerance : ±20ppm

Input Signal Code : HDB3

Out of Signal Code : HDB3

24

Out of Signal Code : HDB3

Return Loss : >20 db in the 3.4 khz to 51 MHz band

Pulse peak Voltage : 1 Vpp ± 75Ω unbal.

Pulse width at half

Amplitude : 14.5ns ±2.45 ns

2/140 Opti-Mux. System Architecture

2/34

Mbit/s

2/34

Mbit/s

1

16

1

1634/140

Mbit/s

2/140

Mbit/sD

25

2/34

Mbit/s

2/34

Mbit/s

16

1

16

1

16

Mbit/s

Elect.

Interface Interface

Mbit/s

Optical

Interface

D

D

F

Specification as per Crompton - Greaves of

140Mbit/s Optical Interface

Bit Rate : 139.520Mbit/s

Line Code : CMI

Type of Laser : FP LASER

(Single-Mode)

26

Wavelength : 1280 -1310 nm

Spectrum Width : ≤4nm

Mean launch optical : ≥-.5dBm(up to-

power 3dBm)

Contd...

Specification of Crompton – Greaves System

of 140Mbit/s Optical Interface

Receiver Sensitivity for : Better than -

BER 1x10 — 10 at 1310nm 32.0dBm

Connector : FC-PC

27

Connector : FC-PC

Documents

Concept of Pdh Multiplexing