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SERVICE PROVIDERS T&M: Benchmarking the QoS

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VoicenData Bureau
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The tremendous growth in wireless subscriber base coupled with increased use

of data applications are making the decision makers at telcos realize the

importance of investing in state-of-the-art T&M equipment. On the other

hand, the emergence of 2.5G and 3G wireless networks meant to support high-speed

data traffic offers new challenges. TRAI's recent paper found most of the

telecom service providers wanting in the QoS parameters. It may be recalled that

TRAI had set a timeframe 36 months for mobile operators and 48 months for fixed

line operators which has got over and is planning to review QoS parameters.

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Technology Trends



Software-based solutions gain Prominence:
T&M equipment manufacturers

are placing greater emphasis on software to make measurements easier to use,

faster, and more accurate. Since these software-based testing equipment use

PC-based platforms, the same hardware can be used to test any of the standards

like GSM, GPRS or CDMA by simply changing the software. In other words, PC is

most likely to become the standard T&M instrument hardware in the near

future with the integration of software testing tools into it.

These solutions are easy to configure (according to user requirements), use

and also come at a lower cost. More than that, for example, National Instruments

promoted the concept of 'virtual instrumentation' allows users to design and

configure their own instruments according to their requirements using software

tools. On the other hand solutions like Agilent Technologies' new wireless

application measurement software (WAMS), the central component of its data

service assurance program, enables RF engineering teams to automate data

traffic, quantify wireless data user experience and find the cause of problems

through leading visualization and analysis tools, thereby reducing the cost of

wireless data rollout.

WAMS enables RF engineers to build complex serial and parallel test sequences

via an easy-to-use and customizable interface. Tests are independent of wireless

technology and include multimedia message service (MMS), short message service (SMS),

HTTP, FTP, e-mail, wireless-application protocol (WAP), and PING.

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Portable T&M instruments: T&M companies are making handheld

T&M devices with more functions and power. For examples, service providers

can expect a growing number of portable analyzers that can meet the needs of

burgeoning field applications. What is good about these instruments is that even

though they are portable they are powerful and feature-packed. Also, many

T&M equipment manufacturers are trying to harness the power and portability

of handheld computers. For example, Noah Industries (Melbourne, FL) offers a

fiber-optic power meter that ties into PDAs and provides graphs of the fiber's

performance.

Realtime RF analyzers: Tektronix has come up with a new series of

real-time spectrum analyzers that provides the ability to trigger, capture and

analyze time-varying RF signals. RF signal characteristics are becoming more

complex as RF communications increasingly replace wired technologies in

applications ranging from inventory identification to video games. Today's RF

signals carry complex modulation and change from one instant to the next,

hopping frequencies, spiking briefly, and then disappearing. As a result, these

RF signals are difficult to measure and present unpredictable behavior, making

engineers' ability to observe RF devices with existing spectrum analyzers

extremely challenging. This evolution in RF technology has spawned an

unprecedented demand for a new approach to spectrum analysis. Realtime spectrum

analysis has emerged as the vehicle to address this RF technology evolution.

  • Digital

    technology is becoming all-pervasive. Whether it is communication systems,

    control systems, radar systems or any other, almost all the analog blocks

    are being replaced by digital. This is bringing profound changes in the area

    of test tools that are required. Signal Analyzers are required to have

    digital demodulation capability while the signal sources are required to

    create signals with digital modulation formats. Mixed Signal Oscilloscopes

    and Logic Analyzers have become a tool of choice for debugging digital

    designs.

  • Whether digital or analog, the designs are moving to

    increasingly higher frequencies. In the digital domain, in order to
    accommodate higher data rates, the signal buses are changing to

    "serial" from the traditional "parallel" ones. This

    brings new and unforeseen challenges for design engineers and manufacturers.

    Signal integrity has become a critical factor for the success of digital

    designs and we see traditional microwave tools like Vector Network Analyzers

    as being used to decide the robustness of design of the physical layer.


  • Induction of new technologies such as VoIP, MPLS, WLAN,

    UWB etc. demand suitable new design and validation tools.

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Tips



Compliance with ITU and International Recommendations:
For most T&M

solutions, the specifications are laid out by the international bodies like ITU-T,

ETSI and ANSI for accuracy and consistency. The buyer must ensure that the

instrument complies with these standards. Since the specifications for the

instrument are much tighter than the equipment or device to be tested, their

compliance with the international body's recommendations is essential. If not,

the results may lose accuracy and repeatability in the measurement

Portability

and Ruggedness:
The equipment should be easy to carry and should have easy

and accessible connections. It should be rugged enough to support wide range of

temperature, jerk and vibrations, and humidity conditions.

Technology support: The instrument should be such that it supports all

the relevant technologies for testing. It means that if the instrument is

designed for the transmission technology testing based on optical fiber then it

should support the currently prevailing technology like SDH, POS and ATM on SDH

together in one box. This allows the buyer for easy testing in the technology

mixed environment and also allows the testing in the area of technology

migration.

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Application fitness: The instrument should not be so much general

purpose to overkill the investment of the buyer. The instrument should target

the correct market segment. For example, there are certain tests that are a must

in field installation and maintenance and these are the key concern areas of the

network operator. The instrument must be able to do all the tests needed by this

segment, but need not include the entire lot of tests required in manufacturing

and R&D. This will result in value for money for the buyer. Operators do not

use R&D and manufacturing types of tests as they come in the area of factory

acceptance test (FAT).

Scalability:

The instrument should be such that it is able to scale to higher bandwidth,

interface, and testing requirement. It should also be possible to upgrade the

instrument without hardware and software limitations so that the investment

remains protected in the evolving technology. For e.g., GPRS and 3G technologies

are still in the growth stage and have not yet matured. Modifications are

happening in these technologies and the instrument should be able to upgrade to

the changing technology and protocols.

Pre- and after-sales support: The company should have a direct

presence in India so that they can advise and optimize the testing and test

times. There should be a strong technical support team in the T&M supplier

company so that instant solutions can be found while troubleshooting.

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Repair and uptime support: The T&M supplier should have a standard

calibration, repair and support center so that support of the order of 24/7 can

be obtained.

Solution level from company: The T&M company should have the core

competence in the area of test and measurement and should not be a non-focus

segment in the company. Also the company should be able to provide the test and

measurement solution in all the segments right form R&D to operations. Such

companies are able to offer the perfect fit for the T&M solution to the

market.

Deployment trends



Next-generation SDH networks will be designed on MPLS technology platform.

VoIP will become popular for voice communication. With the increasing demand on

bandwidth from corporate and SOHO users, both access and long haul networks

would be required to provide broadband capability. Service providers would

increasingly depend on OSS/BSS systems in order to maintain higher QoS and grow

their revenue and profit.

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The

complexity of test systems is driven and defined by the complexity of the

product that is being tested. There is a rapid convergence of varied

technologies into single products and thus there is an increasing onus being

placed on the systems that test them. A perfect example is cellular phones. When

one considers phones from a few years ago, voice was the primary application,

whereas now it is just one among an array of features like camera, video,

Bluetooth, WLAN, gaming, MP3 and video players to name a few.

We see that cellular phones have evolved from being just RF circuitry to

being computing platforms. This means that the phone is a software enabled

device, i.e. a device whose functionality is dictated primarily by the software

that is present on it. And if we look around, we see more and more of such

devices. New features are embedded at an amazing rate and as a result, the

testing of such devices is increasingly challenging. Traditional based

approaches fall well short of the mark when testing such devices. Adding a new

vendor-defined box to test each new feature is ineffective, too cumbersome, and

inflexible.

Often, there isn't a specific instrument built yet to test cutting edge

functionality.

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Looking at the example of a GPS device that are found in most modern cars, we

can see the huge number of traditional instruments required to test such a

device:

The disadvantages of such an approach are clearly visible. Also, any

additional features that need to be tested leave no option but to add another

device.

The virtual instrumentation approach offers a far more effective and

efficient way to solve problems involving the testing of such devices. The only

way to keep up with the changes in design of the devices under test is to employ

a software oriented approach in the test system, and this is the governing

principle behind Virtual Instrumentation.

Communication

Technologies, Transmission Frequencies, and Sample Rates in LAN
Use

the following chart to analyze communication technologies and

technical characteristics use in LANs as art aid in selected

appropriate test instruments.
Technologies Date

Rate
Medium No.

of Pairs Fibers/Wire
Encoding Transmission

Frequency
Digital

Oscilloscope Sampling Rate
FDDI 100

Mbps
Fiber

optic
2 4B5B 125

MHz
250

Msamples/s
CDDI 100

Mbps
Twisted

pair
4 MLT-3 31.25

MHz
62.5

Msamples/s
10base-T 10

Mbps/s
Twisted

pair
2 Manchester 20

MHz
48

Msample/s
10Obase-T 100

Mb/s
Twisted

Pair
4 8B/6T 25

Mhz
50

Msample/s
Gigabit 1000

Mb/s copper
Twisted

pair
4 PA

M5
125

MHz/per pair
250

Msample/s
Gigabit 1000

Mb/s copper
LX 2 8B

/10B
1.25

GHz
2.5

Gsample/s
ATM 155

Mb/s
Twisted

pair
2 CAP-64 25

MHz
50

Msamples/s
ATM 155

Mb/s fiber
Multimode 2 8

B10B
194.4

MHz
388

Msample/s
ATM 155

Mb/s fiber
Plastic

fiber
2 NRZ 155.520

MHz
311

Msample/
ATM 155

Mb/s Fiber
Single

mode
2 Scrambled

1+X6+X7
155.520

MHz
311

Msample/s
ATM 622

Mb/s Fiber
Single

mode
2 Scrambled

1+X6+X7
622.080

MHz
1.24

Gsample/s
ATM 2.4

Gb/s fiber
Single

mode
2 Scrambled

1+X6+X7
2.48832

) GHz
4.9

Gsample/s
ATM 9.9

Gb/s Fiber
Single

mode
2 Scrambled

1+X6_X7
9.953280

GHz
19.9

Gsample/s

A virtual instrumentation system is thus, a predominantly software-defined

system, where software based on user requirements defines the functionality of

generic, modular measurement hardware.

A similar testing application using the virtual Instrumentation approach can

be visualized as seen below:

This approach to testing mirrors the software oriented model of the devices

themselves, and this represents a significant trend in the test and measurement

industry.

The way forward



The way forward is definitely to bring about user defined functionality test

and measurement equipment, and this is one of the unique features of the virtual

instrumentation approach.

It is imperative that the test instrument vendors keep pace with all these

changes. In fact they have to always move ahead in close collaboration of the

global OEMs/ NEMs so that they have the right tools available for validating the

design of the next generation products.

From a hardware perspective, there should be a strong focus on driving the

overall cost down by leveraging commercial technology in computing and

semiconductor technology. From the software front, the way forward is to develop

software that can abstract the system complexity of modern applications by

providing a powerful yet productive means to test even the most complex and

changing technology.

Data Link Layout Audit Measurements:

(OSI Layer2)

Ethernet Token Ring FDDI ATM WAN
- Capacity User



- Activity Statistics


- Communications matrix


- Collisions


- FCS Errors


- Runits


- Jabliers


- Misalignment Errors


- Broadcasts


- Multicasts


- Number Nodes








- Capacity User



- Activity Statistics


- Communications matrix


- Beacons


- FCS Errors


- Ring Purges


- Claim Token Frames


- Receiver Congestion


- Token Rotation Time


- Number of Nodes







- Capacity User



- Activity Statistics


- Communications matrix


- Beacons


- FCS Errors


- Claim Frames


- SMT and Void Frames


- Token Potation Time


- Number of Nodes






- Capacity User



- Activity Statistics


- Communications matrix


- SDH Parameters:

-NAME?



-NAME?


-NAME?


-NAME?


-NAME?


-NAME?



- Total calls

-NAME?



-NAME?

- HEC Errors



- CelSyn Loss


- CelBERT


- Test Cell intersection (o.19)c


delay>


-

ER Capacity User



- Activity Statistics


- Communications matrix


- Connections Statistics (number
of completed of failed connection set ups)



- CRC Errors


- Transmission Delay Measurements



Testing systems based on the virtual instrumentation approach is clearly the

path that the industry is taking. This type of a solution is acknowledged as the

only way to effectively meet the emerging demands of modern test and measurement

applications. Evidence of this is seen from the attitudes of leading

manufacturers as well as consumers.

User issues



Convergence of RF & digital technologies is constantly challenging the

users. They need to rapidly update cross-domain knowledge in order to survive

and contribute in their work. Sometimes, users need to work on new technologies

where standards are yet to be frozen. In this situation the right quality test

tools may not be available.

Rapid

changes in components, devices and hardware technology is reducing the life

cycle of the test instruments. This means customers today need to upgrade sooner

than earlier days.

From the user's perspective, if traditional instrumentation were used to

solve such an application, there would be challenges like a very high number of

devices with a large overall footprint, no inbuilt synchronization platform/bus

to share data between different tests, as well as having to replicate hardware

to test additional functions.

If virtual instrumentation is employed, users have to undergo familiarity

with the approach and the tools involved.

Challenges



The multiplicity of new devices connecting to the wireline and wireless

networks as well as the functionality that they possess is truly astounding. The

greatest challenge faced by the T&M industry is to be able to keep pace and

to effectively give customers ways to test these new devices and technologies.

To manage the cost of telecom networks, many service providers are becoming

extremely sensitive to each and every cost input due to which sometimes quality

of tools is getting compromised. This needs to be addressed immediately so that

the network can continue to deliver quality service. As customers become more

familiar with technology, they would become more demanding and the only way out

for service providers is to improve QoS.

Shrinking life cycle of devices, components and hardware platforms challenge

the test instrument vendors to provide longer support as preferred by customers.

Trends and Drivers



The spending on T&M as part of the network costs is dismally low in

India. While globally, the cost of T&M equipment is 5-8 percent of the total

network cost, in India, the figure is as low as 0.1 percent. Indications are

that the T&M spend will go up in the coming years. More so because the new

service providers are still in the rollout phase. Companies are still seeing

T&M investment as expenditure. However, in future, they will see it as an

investment as they will be required to differentiate on quality, better customer

service, reliable networks and increased productivity.

Earlier, sanctions were a major hindrance in the growth and propagation of

T&M. It must be remembered here that the major suppliers of T&M

equipment are global vendors, primarily those from the US. And the easing of the

US sanctions since October 2001 has enabled them to sell a much broader range of

products.

Service providers bought spectrum analyzers, network analyzers, protocol

analyzers, optical time domain reflectometers (OTDR), optical spectrum analyzers

(OSA) and plesiochronous digital hierarchy and synchronous digital hierarchy (PDH/SDH)

analyzers and handheld testers. BSNL and MTNL were the big customers and they

will continue to remain too as they expand their network further. Private GSM

and CDMA operators too are a huge market for these products as most of them are

talking about improving quality of their network. Further, the thrust today is

on teledensity. As a result, the emphasis will now be on quality of services. So

the potential market for T&M equipment is likely to scale up. The signs are

potent now. Before deregulation, T&M vendors were totally dependent on the

government type of projects.

Primarily, the L1 business dominated the T&M equipment. It meant bulk

purchase of hardware where vendors had no choice but to quote the lowest. Things

have changed now after the entry of the private sector and corporatization of

BSNL. There has been rationalization in procurement. Another noticeable trend is

in solutions. Large vendors are pushing solutions rather than boxes.

Experts

Panel

Jayaram

Pillai,
MD, National Instruments



SR Chowdhury, GM (mktg), T&M Group, Agilent Technologies India

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