TRANSMISSION OVERVIEW

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TRANSMISSION OVERVIEW : 

TRANSMISSION OVERVIEW

Introduction to PDH & SDH : 

Introduction to PDH & SDH MEDIUM Copper - Electrical Wireless - Microwave / Radio Fiber - Optical Satellite

Transmission Types : 

Transmission Types Asynchronous (ATM) Plesiochronous (PDH) Synchronous (SDH)

Slide 4: 

Plesiochronous Digital Hierarchy PDH

PCM Signal Data Rate : 

PCM Signal Data Rate 8bits per sample x = 64kbit/s 8000samples per sec

PDH Systems World-wide : 

PDH Systems World-wide

Plesiochronous Digital Hierarchy : 

Plesiochronous Digital Hierarchy PDH employs PCM multiplexing techniques PDH is one of the most widely used transmission techniques today The basic rate of data transfer in Europe consists of 32 multiplexed base PCM channels offering 2 Mbps (E-1) PDH is standardised by the ITU (not fully) Coaxial cable, optical fibre and radio links are applied for PDH at rates over 2Mbps

The PDH Multiplexing : 

The PDH Multiplexing Drop & Add

Slide 9: 

Synchronous Digital Hierarchy SDH

Synchronous Digital Hierarchy : 

Synchronous Digital Hierarchy Synchronous Digital Hierarchy A new multiplexing hierarchy defined in ITU-T G.707, G.708, G.709, etc.(formerly known as CCITT) Need for extensive network management capability within the hierarchy. Standard interfaces between equipment. Need for inter-working between north American and European systems. Facilities to add or drop tributaries directly from a high speed signal. Standardization of equipment management process.

Synchronous Digital Hierarchy : 

Synchronous Digital Hierarchy An SDH network has to be able to interface and transport the most important PDH signals. 1.5 Mb/s (USA) [1’544 kb/s] 2 Mb/s (Europe) [2’048 kb/s] 6 Mb/s (USA) [6’312 kb/s] 34 Mb/s (Europe) [34’368 kb/s] 45 Mb/s (USA) [44’736 kb/s] 140 Mb/s (Europe) [139’264 kb/s] SDH signals are prefixed with STM-. Today’s standards define: STM-1 155 Mb/s (optical and electrical) STM-4 620 Mb/s (only optical) STM-16 2.5 Gb/s (only optical) STM-64 10 Gb/s (only optical) STM-256 40 Gb/s (only optical)

COMPARISION OF SDH / PDH : 

COMPARISION OF SDH / PDH PDH The reference clock is not synchronized throughout the network. Multiplexing / Demultiplexing operations have to be performed from one level to the next level step by step. The payload is not transparent. PDH system has different frame structures at different hierarchy levels. Physical cross-connections on the same level on DDF are forced if any SDH The reference clock is synchronized throughout the network. The synchronous multiplexing results in simple access to SDH system has consistent frame structures throughout the hierarchy. The payload is transparent. SDH system has consistent frame structures throughout the hierarchy. Digital cross- connections are provided at different signal levels and in different ways on NMS

COMPARISION OF SDH / PDH : 

COMPARISION OF SDH / PDH PDH G.702 specifies maximum 45Mpbs & 140Mpbs & no higher order (faster) signal structure is not specified PDH system does not bear capacity to transport B-ISDN signals. Few services are available. Limited amount of extra capacity for user / management. Bit - by - bit stuff multiplexing SDH G.707 specified the first level of SDH. That is, STM-1, Synchronous Transport Module 1st Order & higher. (STM-1,STM-4,STM-16, STM-64) SDH network is designed to be a transport medium for B-ISDN, namely ATM structured signal. It will transport variety of services. It will transport service bandwidths Sufficient number of OHBs is available Byte interleaved synchronous multiplexing.

Plesiochronous vs. SDH : 

Plesiochronous vs. SDH E1 E2 E3 VC12 STM-1 Plesiochronous (PDH) Synchronous (SDH) SDH provides VC-12 visibility Payload Bit Stuffing

Synchronous Transport Module (STM) : 

Synchronous Transport Module (STM) Smallest transport module: STM-1 = 155 Mbit/s VC are carried in a Transport Module

Transport Module - STM-1 : 

Transport Module - STM-1 Transport Module contains Payload Section overhead (MS & RS) Section overhead contains data to control the node to node transmission: - Protection switching - Error monitoring Plus gives extra channels such as for - Network Management - Maintenance phone link VC’s are carried in Synchronous Transport Modules Smallest transport module: STM-1 = 155 Mbit/s

Transport Module STM-4 : 

Transport Module STM-4 STM-N, (N >= 1) Byte interleaved

SDH Rates NT Portfolio : 

SDH Rates NT Portfolio N 1 4 16 64 STM-n STM-1 STM-4 STM-16 STM-64 NT Portfolio TN-1X/ TN-1P/ TN-1C TN-4X TN-16X, STM-16 4F TN-64X SDH Rates are defined as N x 155.52 Mb/s Mb/s 155.52 622.08 2488.32 9953.28 1 N STM-1 STM-Ne STM-No E/O

SDH Multiplexing Structure : 

SDH Multiplexing Structure

Mapping of 2Mbps into STM – N signal : 

Mapping of 2Mbps into STM – N signal

Mapping of 2Mbps into STM – N signal : 

Mapping of 2Mbps into STM – N signal TU 12 is arranged Into Matrix of 9 X 4

Slide 22: 

Multiplexing

Slide 25: 

261 Columns

Slide 26: 

POH allows end-to-end monitoring The frame is byte interleaved for higher capacity structures(STM-4, STM-16, etc…) Frame repeats every 125 sec regardless of STM-N bit rate(1/8000) Total 270 Columns (Bytes)  9 Columns for overhead 9 Rows 1 10 270

STM-1 Section Overhead : 

STM-1 Section Overhead

Cross Connections : 

Cross Connections

MICROWAVE LINK DESIGN : 

MICROWAVE LINK DESIGN

What is Microwave Communication : 

What is Microwave Communication A communication system that utilizes the radio frequency band spanning 2 to 60 GHz. As per IEEE, electromagnetic waves between 30 and 300 GHz are called millimeter waves (MMW) instead of microwaves as their wavelengths are about 1 to 10mm.

Advantages of Microwave Radio : 

Advantages of Microwave Radio Less affected by natural calamities Less prone to accidental damage Links across mountains and rivers are more economically feasible Single point installation and maintenance Single point security They are quickly deployed

Line-of-Sight Considerations : 

Microwave radio communication requires a clear line-of-sight (LOS) condition Under normal atmospheric conditions, the radio horizon is around 30 percent beyond the optical horizon Radio LOS takes into account the concept of Fresnel ellipsoids and their clearance criteria Line-of-Sight Considerations

Radius of the first Fresnel zone: R=17.32(x(d-x)/fd)1/2 : 

Radius of the first Fresnel zone: R=17.32(x(d-x)/fd)1/2 a Line of sightThe 1:st Fresnell zone, examples of radii at mid path 15GHz 7GHz 38GHz 5km 15km 50km 7m 5m 3m 12m 8m 5m 23m 16m 10m Hop length: d=x+y R

Modulation Techniques, examples : 

Modulation Techniques, examples

Slide 35: 

Each symbol is represented by a combination of carrier phase and amplitude. Low modulation order: + long hops, good resistance to disturbances + fairly uncomplicated technique High modulation order: + high traffic capacity per bandwidth/channel spacing The modulation type is set by the Modem Unit

MINI-LINK E - Main Components : 

MINI-LINK E - Main Components Outdoor moduleSingle coaxial cableIndoor module

Frequency PlanningSub-band Allocation : 

Frequency PlanningSub-band Allocation LOW HIGH LOW LOW NO YES

Frequency PlanningSub-band Allocation : 

Frequency PlanningSub-band Allocation LOW HIGH LOW HIGH LOW

Radio Units : 

Radio Units MINI-LINK Point to point radios are available: In frequencies from 7 to 38GHz In two designs, RAU1 and RAU2 In Standard and High Power versions RAU1 L / RAU2 L: Radio designed solely for MINI-LINK HC RAU1 N / RAU2 N: Radio designed for all MINI-LINK E, TN and HC systems. Please refer to the MINI-LINK E, TN and HC Product Catalog for available frequency bands of respectively radio type

Antenna Units : 

Antenna Units Polarization, Single polarized antennas The polarization is set by turningthe Antenna Feeder

Equipments types based on protection : 

Equipments types based on protection 1+0 System – Single chain of transmit and receive sections. No equipment protection against available failures. 1+1 Hot Standby system – Two chains of transmit and receive sections available on each side of the link to provide protection against operational failure of one chain. 1+1 HSBY can be implemented with 2 antennas ( this is called as Space diversity) or with Single antenna and common waveguide for 2 ODUs. In HSBY both ODUs receive at the same time but only one of the ODU transmits. 1+1 Frequency Diversity( Working Standby) – 1+1 FD is implemented with 2 different frequencies in 2 ODUs. In Frequency Diversity both the ODUs transmit and receive their respective frequencies simultaneously.

Access Module Magazine : 

Access Module Magazine There are different sizes depending of the need on the site and they house the plug-in units. Provides backplane interconnection of traffic, power and control signals.

MINI-LINK TN System Description : 

MINI-LINK TN System Description Magazine Power Filter Unit Fan Node Processor Unit Line Termination Unit Modem Unit Ethernet Termination Unit ATM Aggregation Unit Access Termination Unit Accessories

Radio Antenna Connectivity Using Wave Guide : 

Radio Antenna Connectivity Using Wave Guide

Radio Antenna Connectivity Using Wave Guide & Power Splitter : 

Radio Antenna Connectivity Using Wave Guide & Power Splitter

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