Telecom Technologies-Summary.pdf

EVDO

Introduction

Enhanced Voice-Data Optimized or Enhanced Voice-Data Only (Ev-DO, EV, EVDO, etc.) is a telecommunications standard for the wireless

transmission of data through radio signals, typically for broadband Internet access.

Technology details of EVDO

It uses multiplexing techniques including code division multiple access

(CDMA) as well as time division multiplexing (TDM) to maximize both

individual users' throughput and the overall system throughput. It is

standardized by 3rd Generation Partnership Project 2 (3GPP2) as part of

the CDMA2000 family of standards and has been adopted by many mobile

phone service providers around the world, particularly those previously

employing CDMA networks. EV-DO supports high data rates and is

usually deployed alongside a wireless carrier's voice services. An EV-DO

channel has a bandwidth of 1.25 MHz. The channel structure is so

designed that the back-end network is entirely packet-based(packet

switching), and thus is not constrained by the restrictions typically present on a circuit switched network.

Applications

EVDO is used in almost all wireless cellphones as it provides us with the following features:

1. Always available on seamless roaming

2. Provides crystal clear video on demand, live action 3D games, news, sports, music videos and much more

3. Compatible with almost all OS supporting IP

4. Use Adaptive modulation

5. Offers bandwidth efficiency for data traffic that is 3-4 times greater than other voice centric standards

6. Same range as cell phone signals

Evolution:

CDMA2000 has a long-term evolution path which offers significant

benefits such as enhanced technological performance, low-cost delivery

and short time-to-market. Figure demonstrates the evolution path of the

CDMA2000.

The EV-DO protocol uses asymmetric communication, allocating more

bandwidth for downloads than for uploads. The original EVDO Revision

0 standard supports up to 2.4 Mbps data rates down but only 0.15 Mbps (about 150 Kbps) up.An improved version of EV-DO called Revision A

increased download speeds up to 3.1 Mbps and uploads to 0.8 Mbps (800 Kbps). Newer EV-DO Revision B and Revision C technology supports

significantly higher data rates by aggregating bandwidth from multiple wireless channels. The first EV-DO rev B began rolling out in 2010 with

support for downloads up to 14.7 Mbps.

Comparison with other technologies:

Way forward

Japanese telecom operator KDDI plans to offer 1x Advanced services starting from April 2012. 1x Advanced and EV-DO Advanced will offer up to

4x network capacity increase , multi-carrier links, and smart network management technologies.

SYNCHOROUS DIGITAL HIERARCHY

Background of Technology

The predecessor of SDH is PDH.As digital networks increased in complexity in the early 1980s, demand from

network operators and their customers grew for features that could not be readily provided within the existing

transmission standards. These features were based on high order multiplexing through a hierarchy of increasing

bit rates upto 140Mbps alongwith the introduction of coaxial cable digital transmission. These features were

constrained by the high costs of transmission bandwith and digital devices. The multiplexing technique allowed

for the combining of slightly nonsynchronous rates, referred as to plesiochronous, which led to the term

plesiochronous digital hierarchy (PDH) .The development of optical fiber transmission and large –scale

integrated circuits made more complex standards possible. These were demands for improved and increasingly

sophisticated services that required large bandwidth, better performance and greater network facilities. It was

widely accepted that the new multiplexing method should be synchronous based on PDH and was to replace

PDH. The new multiplexing method (SDH) was to give a similar level of switching flexibility both above and

below the primary rates (1.5 and 2 Mbps).

Focus on Technology

Synchronous Digital Hierarchy (SDH) is a standardized protocol that transfer multiple digital bit streams

over optical fiber. Both SDH and SONET are widely used today: SONET in the United States and Canada, and

SDH in Europe and the rest of the world. Although the SONET standards were developed before SDH, it is

considered a variation of SDH because of SDH's greater worldwide market penetration. The basic unit of

framing in SDH is a STM-1 (Synchronous Transport Module, level 1), which operates at 155.520 megabits per

second (Mbit/s). The major components of SDH are add/drop multiplexer, regenerator, multiplexer and

demultiplexer. SDH layers consists of path, line, section and photonic layers. STM-1 designates a data rate of

155Mbps. This 155Mbps data stream transports also the clock accuracy to the next SDH network element and

synchronizes its clock. Thus a continuous synchronization of SDH network is possible. The clock outputs of the

SDH network elements can be used for the synchronization of further SDH network components.

Applications

It can support bandwidth on demand, can be used as the backbone or totally replace other networking protocols

such as SMDS or FDDI and can replace PDH system,E1, E3 lines.

Benefits over competitive technologies

SDH is flexible, cost effective, manageable and standardized as compared to other competitive technologies.

Way Forward

All new fiber transmission systems now being installed in public networks use SDH. They are expected to

dominate transmission for decades to come similar to their predecessors PDH. Bit rates in long haul systems are

expected to rise to 40Gbps and beyond this in the near future.

Time Division Synchronous Code Division Multiple Access

TD-SCDMA is Acronym for Time Division Synchronous Code Division Multiple Access. Combining time

division and synchronous CDMA gives the TD-SCDMA the capability to handle high data rates and offer high

flexibility to support asymmetric traffic. It is jointly developed by Siemens and the China Academy of

telecommunications Technology (CATT).

One of the key elements of TD-SCDMA is the fact that it uses a TDD. In TDD Uplink and downlink are on the

same frequency band but in different time slots to accommodate the different levels of data transfer, Whereas in

CDMA data is sent on same time interval with same frequency but with different coding technique.

FRAME STRUCTURE TDMA uses a 10ms frame divided into 2 sub-frames each of 5ms. Each subframe has 7 time slots, which can

be flexibly assigned to either several users or to a single user who may require multiple time slots. Each time

slot is of 864 chips and consists of

Data 352 chips

Midamble 144 chips

Data 352 chips

Gap 16 chips

Time-slot #0 is reserved for downlink, and time-slots #1-6 can be used for either uplink or downlink, which can

be flexibly adjusted, while the switching point is the boundary to change from uplink to downlink. Thus,

between two time slots at the switching point there are 3 special time slots Dw-Pts, gap and UpPts.

DwPTS: downlink pilot time is of 96 chips and consists of

Gap of 32 chips

SYNC_DL of 64 chips

UpPTS: uplink pilot time, is of 160 chips and consists of

SYN_UL of 128 chips

Gap 32 of chips

GP: main guard period for TDD, 96 chips

MAIN FEATURES OF TD-SCDMA

• DATA RATE UP TO 2 Mbps

• FLEXIBLE UPLINK – DOWNLINK

• LARGE COVERAGE: UP TO 40 KM

• HIGH MOBILITY: AT LEAST 120 KM/H

• OPTIMUM SPECTRUM EFFICIENCY

IMPROVEMENT IN TD-SCDMA 1. Joint Detection.

2. Power Control

3. Smart Antennas

4. Dynamic Channel Allocation

5. Terminal Synchronization

Dense Wavelength Division Multiplexing

The emergence of Dense wavelength division multiplexing (DWDM, ITU standard G.694.1) is one of the most recent and

important phenomena in the development of fiber optic transmission technology. DWDM technology is a concrete

manifestation of the WDM.

Figure 1: Evolution of DWDM

Dense wavelength division multiplexing (DWDM) uses WDM technology to arrange several fiber optic lights to transmit

simultaneously via the same single fiber optic cable. It can transmit different types of data at different speed on the

same channel by multiplexing of 4, 8, 16, 32 or more wavelengths in the range of 1530nm to 1610nm range (C and L

band) with a very narrow separation between the wavelengths. The channel spacing for DWDM is 0.8/0.4 nm (100

GHz/50 GHz grid). This small channel spacing allows transmitting simultaneously much more information. Thus the

technology creates multiple virtual fibers, thus multiplying the capacity of the physical medium. With DWDM

technology, a single optical fiber capacity nowadays could reach 400 GB/s and this capacity may even enlarge with more

channels being added in DWDM.

Figure 2: DWDM Functional Schematic

A basic DWDM system contains DWDM Terminal Multiplexer, Intermediate Line Repeater, Intermediate Optical

Terminal/ Optical Add-Drop Multiplexer, DWDM Terminal De-Multiplexer and an Optical Supervisory Channel (OSC) The

terminal multiplexer may or may not also support a local EDFA for power amplification of the multi-wavelength optical

signal.

DWDM technology is the order to take full advantage of single mode fiber with low loss area of the enormous

bandwidth resources according to each light wave frequency (or wavelength) different from the low-loss window of the

optical fibers. Today, DWDM is a crucial component of optical networks because of large capacity transmission, saving

fiber resources, access to transparent transmission smooth upgrade and expansion, full use of the TDM technology,

ultra-long haul transmission with the help of EDFA’s and fiber dispersion without excessive requirements.

GPRS & EDGE

Previous Technology GSM :

GSM is a 2G technology which is used for cellular communication system. It was a revolution in the

field of communication as it provided secure communication of the public level that means accessible to all. It

included the FDM and TDM concept. Each carrier of 200 KHz bandwidth is divided into 25 KHz channels and

TDM is then applied on these channels to increase the efficiency of the system. This technology was the

pioneer of the current cellular system. The drawback of this technology was the very less bandwidth i.e., 9.6

Kbps provided to user which could only be used for call and SMS purpose. As users were increasing and more

bandwidth is required to serve the purpose, more bandwidth was required and also to stream multimedia

data there was a need to go ahead and fulfil the loop holes.

GPRS :

It stands for General Packet Radio Service and is considered as 2.5G technology. This technology is

added to GSM and not a separate base. To provide the data service to the user for the first time it introduced

a concept of Packet Oriented Data Service. Its download speed is 56 Kbps and upload is 14.4 Kbps. GPRS is

divided into three classes, A B & C, according to the method of data and voice transmission. Class A sends data

and voice concurrently, B switches between voice and data automatically and C requires manual switching

between the voice and data.

GPRS increased its bandwidth by using the unused bandwidth of GSM. Moreover, in GSM for data

transmission, whole channel was occupied by one user to send DATA but in GPRS more than one user can

share the channel through packet switching and more than one channel is used by a user for data transmission

thus increasing the efficiency of the system using TCP/IP protocol. GPRS uses ACCESS POINT NAMES (APN) to

users so IPs are not viewable. Signaling and data traffic do not travel through the GSM network but is used for

table lookup (HLR and VLR) data bases to obtain GPRS user profile data.

Current GSM architecture cannot handle packet switching so two new components are introduced that

are SGSN and GGSN. SGSN delivers packets to MSs within its own area and send queries to HLR to get profile

data. GGSN is used to interface with external IP Networks. It maintains the routing information that is

necessary to tunnel the protocol data units.

EDGE :

It stands for Enhanced Data GSM Environment and is considered as 2.75G. It provides 384 Kbps

download speed and 135 Kbps upload speed. Because of greater bandwidth it enabled the delivery of

broadband apps. It is also based on GSM technology and after GPRS, it do not require a new hardware

addition but a software upgrade. It uses 8-PSK with the old GMSK to achieve high bandwidth. The symbol rate

stays the same that is 271 Kbps but using 8PSK, one symbol has 3 bits which enhances the amount of data per

timeslot to 69.2 Kbps which is three times of GMSK. It is the last technology before 3G. So it was step ahead

towards 3G which is a WCDMA technology.

SONET

ULTRA MOBILE BROADBAND (UMB)

WIFI

GSM

Evolved High Speed Packet Access (HSPA+)

LTE

G.729

IPTV

PREDECESSOR TECHNOLOGY AND ITS DRAWBACK: In the 21st century, the access with broadband internet and downstream data rates of several Megabits per second is making a steady progress. With the increasing number of households are getting used to video streaming and download, use of the Internet Protocol (IP) to enable interactive retrieval of video content from the Web. This type of IP based television service is known as WebTV. However WebTV does not provide a guaranteed quality of service (QoS). Therefore now the telecommunication companies are making an attempt to overcome the deficiencies of WebTV and launched the IPTV.

TECHNOLOGY: Internet Protocol Television (IPTV) is a system where a digital television service is delivered over Internet Protocol network. IPTV works on the TV with a set-top box that accesses channels, subscription services, on demand and other interactive multimedia services over a secure, end-to-end operator managed broadband IP data network with desired QoS to the public with a broadband Internet connection. IPTV system may also include Internet services such as Web access and VOIP where it may be called Triple Play and is typically supplied by a broadband operator using the same infrastructure. IPTV is not the Internet Video that simply allows users to watch videos, like movie previews and web-cams, over the Internet in a best effort fashion. Triple Play is delivered using a combination of optical fibre and digital subscriber line (DSL) technologies to its residential base. Cable television operators use a similar architecture called hybrid fibre coaxial (HFC) to provide subscriber homes with broadband, but use the available coaxial cable rather than a twisted pair for the last mile transmission standard.

IPTV ARCHITECTURE: A typical IPTV architecture is comprised of the following functional blocks: • Super head-end: Where most of the IPTV channels enter the network from national broadcasters • Core network: Usually an IP/MPLS network transporting traffic to the access network • Access network: Distributes the IPTV streams to the DSLAMs • Regional head-end: Where local content is added to the network • Customer premises: Where the IPTV stream is terminated and viewed

Video on Demand: The idea of this to allow viewers to watch any programme they desire whenever they want to watch. The concept of VOD is based on video programming that is stored and then delivered to a viewer when it is required. This storage can take the form of a centralised server. Individual storage devices for each viewer can be located in individual STBs.

Delivering IPTV service with QoE: QoE is the overall performance of a system from the point of view of the users. IPTV provides better QoE as compared to the Analogue and Web TV.

An IP set-top box is a device that serves as an interface between a television set and a broadband network. In addition to decoding and rendering broadcast live TV signals, a set-top box provides applications that includes video-on-demand (VOD), electronic program guide (EPG), digital rights management (DRM), and a variety of interactive and multimedia services. Set-top boxes can support additional features such as Web browsing, e-mail and viewing e-mail attachments, advanced multimedia codecs, home networking and PC connectivity including playback and rendering of content stored on the PC (photos, music, and personal videos), gateway functionality, instant messaging (IM), and real-time voice over IP (VoIP).

IPTV FEATURES: IPTV has number of features including the two-way capabilities of IPTV systems allow service providers to deliver a whole raft of interactive TV applications such as standard live TV, high definition TV (HDTV), interactive games, and high speed Internet browsing. IPTV in combination with a digital video recorder permits the time shifting of programming content. An end-to-end IPTV system supports bidirectional communications and allows end users personalize their TV viewing habits. IPTV technologies allow to only stream the channel that the end user has requested. This feature allows network operators to conserve bandwidth on their networks.

IPTV BENEFITS: • IPTV signals are 100% digital, so the days of analogue TV are fast becoming a thing of past. • IPTV works on any existing internet connection. So we just need to install the set-top-box and power it on. • IPTV doesn’t require to wires to get its signal. The newest IPTV set-top-boxes work on wireless signals. • Programs can be stored on servers and ready to view with the click of a button on IPTV remote

Long Term Evolution – Advanced Why LTE isn’t really 4G Long Term Evolution (LTE) is frequently marketed by telecomm operators as being 4G. However, it doesn’t meet the requirements of the International Telecommunications Union, Radio communications Sector (ITU-R) for 4G technologies, which are that static users must get an achievable data rate of 1 Gbps, and mobile users that of 100 Mbps. Any person not in a vehicle considered static. The original version of LTE didn’t meet these requirements. It had a maximum data rate of 168 Mbps/22 Mbps on its introduction, with the HSPA+ standard. Thus, ITU-R classified “plain” LTE as 3.9G, as it was well beyond the specifications required by 3G, but didn’t meet the requirements for 4G.

Why LTE-A? Since LTE wasn’t really 4G, the need for a true 4G network was felt. The 3rdGeneration Partnership Project (3GPP) agreed upon a set of design requirements for E-ULTRA, which was later renamed to LTE-A. Some of the design requirements were:

It must meet the requirements set forth by ITU-T for 4G technologies.

It must be backward compatible with LTE, i.e. LTE-A base stations can work with LTE radios and vice versa.

A channel/user can occupy more of the spectrum depending on the data rate requirement.

Faster switching between power states (modulation scheme, transmission power).

Improved performance between cell edges.

Research Conducted to Meet the Requirements 8x8 Modulation Antennas were proposed (8 input, 8 output spectrum portions)

Modulation schemes reaching up to 128-QAM

Channel Bandwidth variable upto 100 MHz up from 20 MHz

Usage of portions of the spectrum that aren’t contiguous.

Usage of frequencies from 3rd party communication systems in the absence of licensed users (Cognitive Radios)

Enhanced precoding and forward error correction schemes.

Orthogonal FDMA (OFDMA) and Single-Carrier FDMA (SC-FDMA).

Cell breathing concept, where an overloaded cell can reduce its range if required.

Frequencies are dynamically allocated to cells, to allow for compensation in the mismatch of cell loads.

Improved Power Management.

So, is this technology here yet? It certainly is. The first successful test trial was in February, 2007 by DoCoMo, Japan. The first commercial deployment was in October, 2012 by Yota in Moscow. The first LTE-A compatible phone to be released was a variant of the Samsung Galaxy S4 in June, 2013. LTE-B, or LTE-A phase 2, has been proposed as the successor to LTE-A, and its main feature is that it provides 30 times the received power at the cell edge.

HSPA

HSPA - High Speed Packet Access is the most widely deployed mobile broadband technology in the world today. HSPA is

the terminology used when both HSDPA and HSUPA technologies are deployed on a network. HSPA+ (Evolved HSPA) is

also part of the HSPA technology and extends an operator’s investment in the network before the next step to LTE (Long

Term Evolution). HSPA builds on third generation (3G) UMTS/WCDMA and is strongly positioned as the leading mobile

data technology. The original 3G UMTS/WCDMA standard provided a maximum of 2 Mbps in downlink and 384 Kbps in

uplink.

The first step required to upgrade WCDMA to HSPA is to improve the downlink by introducing HSDPA. The improved

downlink provides up to 14 Mbit/s with significantly reduced latency. The improvement in speed and latency reduces

the cost per bit and enhances support for high-performance packet data applications. The second major step in the

WCDMA upgrade process is to upgrade the uplink. Upgrading to HSUPA is usually only a software update. Enhanced

Uplink adds a new transport channel to WCDMA, called the Enhanced Dedicated Channel (E-DCH). An enhanced uplink

creates opportunities for a number of new applications including VoIP, uploading pictures and sending large e-mail

messages. The enhanced uplink increases the data rate (up to 5.8 Mbit/s), the capacity, and also reduces latency.

HSPA provided up to five times more system capacity in the downlink and up to twice as much system capacity in the

uplink compared with original WCDMA protocols. The improvement of WCDMA to HSPA is achieved in several ways:

Shared-channel transmission, which results in efficient use of available code and power resources in WCDMA

A shorter transmission time interval (TTI), which reduces round-trip time and improves the tracking of fast

channel variations

Link adaptation, which maximizes channel usage and enables the base station to operate at close to maximum

cell power

Fast scheduling, which prioritizes users with the most favorable channel conditions

Fast retransmission and soft-combining, which further increase capacity

16-QAM and 64-QAM (quadrature amplitude modulation), which yields higher bit-rates

MIMO, which exploits antenna diversity to provide further improvements in bit-rates and system capacity.

A further improved 3GPP standard, Evolved HSPA (also known as HSPA+), was released late in 2008 with subsequent

worldwide adoption beginning in 2010. The newer standard allows bit-rates to reach as high as 168 Mbit/s in the

downlink and 22 Mbit/s in the uplink. Technically these are achieved through the use of a multiple-antenna technique

known as MIMO (for "multiple-input and multiple-output") and higher order modulation (64QAM) or combining

multiple cells into one with a technique known as Dual-Cell HSDPA.

There are some limitations to this technology e.g. the 168 Mbit/s and 22 Mbit/s represent theoretical peak speeds. The

actual speed for a user will be lower. In general, HSPA+ offers higher bitrates only in very good radio conditions (very

close to cell tower) or if the terminal and network both support either MIMO or Dual-Cell HSDPA. Nevertheless this is a

huge success in telecommunication industry; it has increased the data transmission speeds, has overcome the

drawbacks of previous technologies and above all HSPA+ has provided a road towards 4G. It has delivered significant

battery life improvements and dramatically quicker wake-from-idle time, delivering a true always-on connection. It has

allowed the telecom operators to move towards 4G speeds without deploying a new radio interface. 4G LTE requires a

new radio interface i.e. OFDM which will involve complete change of infrastructure.

ADSL and ADSL 2+ INTRODUCTION:

DSL provides internet access by transmitting digital data over the wire of a local telephone network. DSL supports voice,

data, and video but have some drawbacks as well e.g farther you live from DSLAM lower will b the data rate and no

current standardization, expensive, low or no CIR then rural areas get shorted. So we move to new technologies.

ADSL (Asymmetric Digital Subscriber Line)

ADSL is a Data communications technology that enables faster data transmission over copper telephone lines. Providing

Faster downstream than upstream (asymmetric). Data transmission speed is approximately 50Mbps when the subscriber

is within 5.5km range from exchange. ADSL speed depends on factors like distance from the exchange (more distance

less speed), type and thickness of wire (more thick more speed) and number of joints (lesser joints more speed). ADSL

modem at the customer premises, modem of the central office, DSL access multiplexer (DSLAM), Broadband Access

Server (BAS) and Splitter (the analogue voice or ISDN signal from ADSL data frequencies DSLAM) are the basic ADSL

network components. Digital signal modulation to electronic waveform is accomplished through the two modulation

techniques CAP (carrier less amplitude phase)or DMT(Discrete Multi-tone).CAP will modulate the signal into 2

frequency bands upstream(25 and 160kHz) and downstream(200kHz to 1.1MHz). In DMT signal is separated into 256

channels of 4.3125 kHz each.DMT has 224 downstream frequency carriers and 32 upstream frequency carriers.

ADSL 2 (TECHNOLOGY BETWEEN ADSL & ADSL2+)

ADSL2 (ITU G.992.3 and G.992.4) adds new features and functionality targeted at improving performance and

interoperability and adds support for new applications and services. Among the changes are improvements in ADSL's data

rate, an increase in the distance ADSL can reach from the local telephone exchange, diagnostics, and a stand-by mode to

save power. ADSL2 also reduces the initialization time from more than 10 seconds (as is required for ADSL) to less than

3 seconds. Due to some physical limitations maximum theoretical peed of ADSL2 is not achievable. ADSL2 operates at a

higher frequency and is more sensitive to interference, noise and attenuation.

ADSL2+

ADSL2+ standardized by the ITU as "G.992.5" is the further development of ADSL. ADSL2+ reaches a maximum

bandwidth of 25 M Bit/s downstream and 1 M Bit/s upstream. This triplication of speed was realized by doubling the used

frequency spectrum from formerly 25-1104 kHz to 25-2200 kHz and some other advancements of the signal modulation.

The bandwidth ADSL2+ is dependent on signal attenuation, that in turn depends on the length of the telephone line from

your ADSL modem to the DSLAM located at the local telephone exchange, the farther one is away from the telephone

exchange, the lower the expectations of ADSL2+. ADSL2+ Reduced cross talk, Allows provision of advanced services

and Builds on all ADSL2 features.

CDMA 2000

CDMA2000 is a third generation (3G) standard developed by the international Telecommunication Union

(ITU). This protocol uses CDMA access to send voice, data and signals between mobile phones and cell sites.

The CDMA2000 technology evolved from CDMAone technology. CDMAone was the first cellular standard to

implement the CDMA multiple access scheme, also known as IS-95. CDMAone is considered as a second-

generation (2G) mobile wireless technology. Individual channels can be distinguished from one another by

means of unique orthogonal codes. There are two versions of IS-95, called IS-95A and IS-95B. Apart from

voice, the mobile phone system is also able to carry data at rates up to 14.4 kbps for IS-95A and 115 kbps for

IS-95B.

The motivation behind the evolution of CDMA 2000 was comparatively slow data rates of CDMA IS-95

networks whereas CDMA2000 data rates are much faster. CDMA IS-95 was a 2G technology whereas,

CDMA2000 1X is a 3G technology that offers both voice and data capabilities. On the basis of security CDMA

IS-95 had shortcomings like extensive cryptanalysis of algorithms used in 2G systems, 64-bit keys used in 2G

systems are found to be too short for a strong encryption and there were new requirements like the need for

mutual authentication.

Direct Sequence Spread Spectrum (DSSS) Multiple Access, Orthogonal Code Channelization, Random

Access, Soft Handoff, Scrambling, Speech Regulated Vocoders and Single Frequency Reuse are the

characteristics of CDMA2000 1x that are derived from its CDMA roots and make it backward compatible with

CDMAone.

CDMA2000 is a code-division multiple access (CDMA) version of the IMT-2000 standard developed by the

International Telecommunication Union (ITU). It is a 3G mobile technology.

CDMA2000 represents a family of standards which includes technologies as listed below.

CDMA2000 1xRTT (144 kbps now, 307 kbps in the future )

CDMA2000 1xEV-DO:Release 0 Revision A, Revision B, Revision C or Ultra Mobile Broadband (UMB)

CDMA2000 1xEVDV (3.09Mbps)

CDMA 2000 3XRTT

CDMA2000 has several advantages. It has the ability to use signals that arrive in the receivers with different

time delays (multipath). It uses the multipath signals and combines them to make the cellular signal stronger.

CDMA networks use a scheme called soft handoff, which minimizes signal breakup as a handset passes from

one cell to another. It has a very high spectral capacity and reduces background noise.

Today, CDMA2000 operators offer thousands of applications targeting Consumers, Businesses and Public

service organizations.

MIMO

In Time diversity same information is repeatedly transmitted at sufficiently separated (more than coherence time) time

instances.

In Frequency diversity same information is repeatedly transmitted at sufficiently separated (more than coherence

bandwidth) frequency bands. Polarization diversity combines pairs of antennas with orthogonal polarizations. Reflected

signals can undergo polarization changes depending on the medium through which they are travelling. By pairing two

complementary polarizations, this scheme can immunize a system from polarization mismatches that would otherwise

cause signal fade.

Space diversity techniques do not require any additional time or frequency

resource. space-time diversity employs multiple transmit antennas, not requiring

additional time resource. Space-frequency diversity employs multiple transmit

antennas, which do not require additional frequency resource. MISO is a form of

space diversity, where there are multiple antennas at the receiver. we do

intelligent weighing and sum at receiver to obtain transmitted signal. SIMO is a

type of space diversity used to diminish the effects of fading by transmitting

the same information from different antennas.

In radio, multiple-input and multiple-output, or MIMO, is the use of multiple antennas at both the transmitter and

receiver to improve communication performance. It is one of several forms of smart antenna technology. Note that the

terms input and output refer to the radio channel carrying the signal, not to the devices having antennas. MIMO

technology has attracted attention in wireless communications, because it offers significant increases in data throughput

and link range without additional bandwidth or increased transmit power. It achieves this goal by spreading the same

total transmit power over the antennas to achieve an array gain that improves the spectral efficiency (more bits per

second per hertz of bandwidth) and/or to achieve a diversity gain that improves the link reliability (reduced fading).

Because of these properties, MIMO is an important part of modern wireless communication standards such as IEEE

802.11n (Wi-Fi), 4G, 3GPP Long Term Evolution, WiMAX and HSPA+.

Spatial multiplexing techniques make the receivers very complex, and therefore they are typically combined with

Orthogonal frequency-division multiplexing (OFDM) or with Orthogonal Frequency Division Multiple Access (OFDMA)

modulation, where the problems created by a multi-path channel are handled efficiently. The IEEE 802.16e standard

incorporates MIMO-OFDMA. The IEEE 802.11n standard, released in October 2009, recommends MIMO-OFDM.

MIMO is also planned to be used in Mobile radio telephone standards such as recent 3GPP and 3GPP2. In 3GPP, High-

Speed Packet Access plus (HSPA+) and Long Term Evolution (LTE) standards take MIMO into account. Moreover, to fully

support cellular environments.

MIMO technology can be used in non-wireless communications systems. One example is the home networking standard

ITU-T G.9963, which defines a power line communications system that uses MIMO techniques to transmit multiple

signals over multiple AC wires (phase, neutral and ground).

Next Generation Network (NGN)

Today, telephony, the Internet, and the cellular mobile networks continue to be different domains; each has its

own protocols and services. NGN will be the foundation for the creation of a new range of multimedia

applications that takes full advantage of the characteristics of the broadband network and the “always on”

capability.

Today’s network is divided into:

• The Public Switched Telephone Network,

• The packet Switched Networks(e.g. the Internet) and

• The Mobile networks.

Convergence is the process of interconnection of traditional switched circuit networks (the PSTN and mobile

networks) and packet-switched networks based on the Internet Protocol (IP) for routing.

Packet-based network able to provide telecommunication services and able to make use of multiple broadband,

QoS-enabled transport technologies and in which service-related functions are independent from underlying

transport-related technologies. It enables unfettered access for users to networks and to competing service

providers and/or services of their choice. It supports generalized mobility which will allow consistent and

ubiquitous provision of services to users.

The general idea behind the NGN is that one network transports all type of data and provide services (voice,

data, and all sorts of media such as video) by encapsulating these into packets, similar to those used on the

Internet.

NGNs are commonly built around the Internet Protocol (IP), and therefore the term all IP is also sometimes

used to describe the transformation toward NGN.

Next generation networks are not just a PSTN replacement but at a minimum they must provide the equivalent

voice quality and reliability of today’s PSTN.

The NGN will be the foundation for the creation of a new range of multimedia applications that take full

advantage of the characteristics of the broadband network.

The creation of the NGN is no overnight transformation, but it is an evolution that is already underway and

gathering pace.

The NGN is the shift from separate application-specific networks to a single network capable of carrying any

and all services.

OFDM

A predecessor to OFDM was FDM. In FDM, the carrier frequencies were spaced such that the signals did not overlap.

Guard bands were placed between the signals to ensure that they could be separated with the use of filters at the receiver.

This resulted to insufficient utilization of the existing spectrum. As years passed, demand of bandwidth increased and in

mid 1960s an idea was proposed to deal with this wastefulness caused by FDM with overlapping sub-channels. This idea

became the basis for OFDM, stating that provided the carriers are orthogonal, sidebands of the individual carriers would

not cause ISI. Later, it was discovered that sub-channel’s orthogonality in the OFDM system can be preserved through the

QAM technique.

(OFDM) is a multi-carrier modulation scheme that extends the concept of single subcarrier modulation by using multiple

subcarriers within the same single channel. Rather than transmit a high-rate stream of data with a single subcarrier,

OFDM makes use of a large number of closely spaced orthogonal subcarriers that are transmitted in parallel but at a lower

rate. Each subcarrier is modulated 16QAM at low symbol rate. However, the combination of many subcarriers enables

data rates similar to conventional single-carrier modulation schemes within equivalent bandwidths. A guard interval is

added to each symbol to minimize the channel delay spread and inter-symbol interference. In a simple OFDM system

there are N sinusoidal input signals. Each subcarrier transmits m bits of information (N*m bits total). The frequency of

each subcarrier is selected to form an orthogonal signal set. These frequencies are also known at the receiver for signal

recovery. To maintain orthogonality, T must be the reciprocal of the subcarrier spacing. In the frequency domain, each

transmitted subcarrier results in a sinc function spectrum with side lobes that produce overlapping spectra between

subcarriers. This results in subcarrier interference except at orthogonally spaced frequencies. At orthogonal frequencies,

the individual peaks of subcarriers all line up with the nulls of the other subcarriers. This overlap of spectral energy does

not interfere with the system’s ability to recover the original signal. The receiver multiplies (i.e., correlates) the incoming

signal by the known set of sinusoids to recover the original set of bits sent. The use of orthogonal subcarriers allows more

subcarriers per bandwidth resulting in an increase in spectral efficiency.

OFDM is a modulation format that is finding increasing levels of use in today's radio communications scene. OFDM has

been adopted in the Wi-Fi arena. In addition to this, it is being used for WiMAX and is also the format of choice for the

next generation cellular radio communications systems including 3G LTE and UMB. It’s also used for digital terrestrial

television transmissions, Digital Audio Broadcasting, ADSL and Mobile phone 4G.

OFDM is a competitor of CDMA having numerous advantages over it. OFDM is more effective in handling multipath and

it’s more spectrally efficient. There is no upper limit to the data speed you can achieve with OFDM. ISI is less of a

problem with OFDM because low data rates are carried by each carrier. OFDM can easily adapt to severe channel

conditions without the need for complex channel equalization algorithms being employed. It is robust when combating

narrow-band co-channel interference. As only some of the channels will be affected, not all data is lost and error coding

can combat this. It allows the use of a single frequency network to provide excellent coverage and good frequency re-use.

The PAPR Value of OFDM is an important factor that determines the quality of the connection. The future of OFDM lies

in improving the PAPR value, so that it can be made more efficient and robust. Engineers are doing important research to

improve it, as a result 4G, 5G and future protocols are and will be defined.

WCDMA

W-CDMA, PREDECESSOR AND SUCCESSOR: W-CDMA is a spread-spectrum modulation technique; one

which uses channels whose bandwidth is much greater than that of the data to be transferred. Instead of each connection

being granted a dedicated frequency band just wide enough to accommodate its envisaged maximum data rate, W-CDMA

channels share a much larger band. WCDMA was the 3G technology used in the US by AT&T and T-Mobile. WCDMA

is the standard that most GSM carriers moved to when upgrading to 3G. Parts of the WCDMA standard are based on

GSM technology. WCDMA networks are designed to integrate with GSM networks at certain levels. Most WCDMA

phones include GSM as well, for backward compatibility.

WCDMA borrows certain technology ideas from CDMA, as the name implies, but is in fact very different and

incompatible with phones and networks using "CDMA" technology. WCDMA is also referred to as UMTS - the two

terms are effectively interchangeable. UMTS uses a core network derived from that of GSM, ensuring backward

compatibility of services and allowing seamless handover between GSM access technology and W CDMA.

There are several newer upgrades to WCDMA that offer much faster data speeds, such as HSPA and HSPA+.

These do not replace WCDMA, but rather build on and enhance WCDMA. Therefore any phone with HSPA or HSPA+

also includes WCDMA by definition.

W-CDMA TECHNOLOGY: The modulation technique encodes each channel in such a way that a decoder, knowing

the code, can pick out the wanted signal from other signals using the same band, which simply appear as so much noise.

In Europe and Asia, WCDMA was first deployed in the all-new 2100 MHz frequency band . In North America, WCDMA

was deployed in the existing 1900 MHz (PCS) and 850 MHz (cellular) bands, as well as the newer 1700 MHz (AWS)

band. W-CDMA can support mobile/portable voice, images, data, and video communications at up to 2 Mbps (local area

access) or 384 Kbps (wide area access). A 5MHz-wide carrier is used, compared with 200 KHz-wide carrier for

narrowband CDMA.

APPLICATIONS: Microsoft NetMeeting Application, Wireless Video Telephony, achieve higher speeds and support

more users compared to most time division multiple access (TDMA) and time division duplex (TDD) schemes used

before. W-CDMA has become the dominant technology with 457 commercial networks in 178 countries as of April

2012. Several cdma2000 operators have even converted their networks to W-CDMA for international roaming

compatibility and smooth upgrade path to LTE.

BENEFITS OVER COMPETING TECHNOLOGIES: The strong points, also known as selling points, of

WCDMA technology are high bandwidth/transmission speed, plus improvements on 2 and 2.5G GSM/GPRS networks

like better speech quality, more capacity, no frequency planning as such, etc. Also, with the amount of bandwidth

available for WCDMA, each channel is able to support between 170 to 175 users.

WAY FORWARD: The need to allow for high speed data transmission over packet switched wireless networks,

instead of the current circuit switched systems. Plans to use matched filtering technology with WCDMA would also yield

great benefits, such as decreased acquisition time, and increased battery life of wireless devices. It also allows for easy

identification of the multipath components. Another enhancement possible for WCDMA would be the use of signal

processing techniques on the uplink.