T&M: Prevention Is Better than Cure

Oscilloscopes to high-end analyzers–those are the solutions that the

T&M industry spans. The products would include spectrum analyzers, network

analyzers, protocol analyzers, logic analyzers, oscilloscopes, and handheld

testers. In the communications sector, these products are used in the wireless

networks, the wired networks, and the LAN/WAN environments. These products also

find significant use in the broadcast and in educational institutes, and

software houses. The last two especially use these products for the R&D in

communications.

Technology Options

This is one sector that has to be always ahead of the emerging technology

trends. Be it in the semiconductor or the manufacturing or the service provider

segment, T&M products have to be ahead or on par with the emerging industry

standards, as they have to facilitate the deployments. Take for example

wireless: Everyone knows that 3G is in trials or is getting deployed in some

places. Now for the deployment of the 3G networks, the service providers will

look for the latest test equipment from the T&M vendors to allow them to

define and manage their networks. Similarly, the 3G phone makers would require

test equipment in their manufacturing processes. So players like Agilent,

Acterna, and Tekronix have products that facilitate the services and

manufacturing. The products that would be used in communications sectors like

the testers, simulators, and analyzers have to be in consonance with the latest

developments in ATM, bit-error-rate, cable (metal and optical), DSL, Frame

Relay, ISDN, modems, MPEG, SDH/PDH/SONET, voice over packet, RF/microwave, and

optical, among other things.

n Analyzers: Spectrum

analyzers and network analyzers have been the next common general-purpose test

and measurement instruments after oscilloscopes. The spectrum analyzer sketches

a signal in the frequency domain like an oscilloscope, which sketches a signal

in the time domain. Spectrum analyzers plot the voltage for each frequency

component of the signal. An oscilloscope plots instantaneous voltage of a signal

versus time. Spectrum analyzers can measure frequency, power, harmonic content,

modulation, spurious, and noise. But it is being transformed as an

application-specific tester. Most of the Spectrum Analyzers required are below

4GHz.

Network analyzers are used to watch a wide variety of devices, from

components and materials to circuits, equipment, assemblies, and systems. It

measures the transmission and reflection characteristics of linear circuit

networks. There are two main types of network analyzers–scalar and vector. The

scalar network analyzers measure only the amplitude portion of the S-parameters

resulting in measurements such as transmission gain and loss, return loss, and

standing wave ratios (SWR). Vector network analyzer measures and also shows the

complete amplitude and phase characteristics of an electrical network. The shift

is in favor of vector network analyzers.

n Newer

Solutions: Advances in communications technologies have led to test

equipment that can evaluate new emerging standards. So there has been

upgradation in the modulation and demodulation techniques is areas like GSM and

CDMA. These features have been incorporated in signal analyzers too. Need for

greater capacity and faster throughput has let to creation of different testing

parameters. For example, vendors are today prepared to test 80 gigs too.

n Change, the

Only Common Factor: Take a basic time-domain tool like an oscilloscope. For

today’s mixed signal applications the engineers require mixed signal

oscilloscopes to view and trouble shoot analog and digital parts of the circuit

simultaneously.

Today, spectrum analyzers are no longer simple frequency domain instruments.

They come with application personalities to solve the format specific

measurement problems like GSM, CDMA, and 3G. A data tool like logic analyzer has

to provide deeper insight and solve the signal integrity problems through

higher-level abstraction of data.

n A Management

Solution: In the last couple of years, T&M has moved from being a

hardware product to a software solution. Today, it is more about a management

solution.

Buying Tips

n Compliance

with Standards: One of the most important things to consider is to look if

the products are compliant with the specifications laid out by standards

organizations like ITU, ISO, ETSI, and ANSI. This is because the results of

using the solution have to be effective and accurate.

n Portability

and Ruggedness: This is a very important consideration, as the instruments

need to be easily accessible and should be capable of sustaining various

environmental conditions, particularly if the units are used in field.

n Scalability:

The solution has to be scalable, as it has to meet up with the evolving

technologies. The solution should allow the upgrades to happen easily through

software management. Scalability has to be in newer and deeper measurement

through software.

n Niche

Solutions: Going for general-purpose instruments, which do not address the

specific sector, could be a bad investment. This approach will allow conduct of

the tests that are necessary.

n Product

Roadmap and Support: This should be a consideration, as it will allow one to

go for a scalable solution and prevent from having an obsolescent product. As

vendors phase out products, the support would become important so that the

network would not suffer. Also, going for vendors who provide good pre-sales and

post-sales support along with the local technical and applications support can

help the solution to be finely tuned at all times. And can help one to look at a

good migratory path.

Market Information

n Promising

Market: The market for T&M has been active and promising. The total

market is estimated to be about Rs 250-275 crore by March this year. It is not

just the communications sector that has been attractive, the broadcast and

education markets too have been aggressive. Moreover, there has been sale to the

defense and PSUs too.

n Telco

Ramp-up: Traditionally, BSNL and MTNL were the big buyers. But others are

moving in fast. There has been increased activity in the private sector both on

the GSM and CDMA front. The two largest corporate houses in India, Tata and

Reliance, rolled out their services. Others like Bharti, BSNL, and Hutch have

consolidated and announced new launches. Overall, telecom services, be it the

basic, cellular, broadband, DLD, or ILD, are growing. Market estimates suggest

that Reliance must be investing about $15—20 million on test, monitoring, and

management. Bharti’s investment is estimated to be about $5 million and that

of Tatas around $3 million.

n QoS Drive: The

focus of operators is and will be on customer acquisition and high-definition

services. This means each of them is using the latest in technology like SDH or

SDH over DWDM or DWDM or TDMA/IP or CDMA 2000 1X or GPRS. The investment is

coming in T&M to support quality networks, network operating centres, and

central processing offices. Service providers are realizing that they cannot

perform without T&M solutions.

n Defense,

Broadcast Big Buyers: Besides the communications sector, the broadcast and

education markets have been aggressive. Moreover, there have been sales to the

defense and other PSUs too. The easing of US sanctions since October 2001 has

enabled several global players like Agilent, Acterna, and Tektronix to sell

their products all around. During the sanctions, they were not able to sell even

oscilloscopes with 1G sample/second performance. Today, they can even sell to

agencies like Aeronautical Development Establishment, the Electronics and Radar

Development Establishment, Bharat Electronics, HAL, DRDO, ISRO, among other

entities. The licenses to supply get cleared in four-six weeks time.

n Solutions,

not Just Boxes: Most of the large vendors today talk of a solution. Even

oscilloscopes are being sold with solutions built around them. The solutions

approach will stay as the service providers would be looking at network

monitoring, QoS for various networks–be it the data, optical, mobile,

satellite, or cable TV–and fraud/churn management as some of the main ways to

bring about service differentiation. T&M business is changing from

tender-basis to rational investment procurement decision. However, it will take

time before T&M will be seen as a tool for justifying the return on

investment.

n Big Vendors

Rule: Most of the leading vendors like Agilent, Acterna, and Tektronix have

made significant wins. Some of the large orders that were finalized last year

were that of MTNL for 24 OTDR-Type B, 9 SDH analyzers STM 1/4 and SDH analyzers

STM1/4/16; BSNL tender for 175 mini OTDRs, 20 WDM analyzers, 38 OTDRs. These

orders were close to Rs 70 crore. This year the investment on OTDRs has been

slightly less considering the fact that most of the fiber backbone has already

been built. During the globally downturn period, in the past couple of years

too, the T&M vendors grew on an average of 10—12 percent. But this year,

they could be seeing close to 20—25 percent growth.

While Agilent Technologies has complete portfolio of solutions for all types

of telecom providers assisting through design, network optimization, technology

migration, and implementation from spectrum analyzers to network analyzers to

antenna testing, Tektronix is very strong in protocol analyzers, besides other

products. It is believed that Tektronix has close to 85 percent market share in

this arena. Acterna is strong in the OTDR and DWDM analyzers and has solutions

covering optical transport, cable, wireless, data IP, and access network.

Others like ICT, Fastech, Anirtsu, Seven Hills, Aishwarya Telecom, and

Trinity Electronics have also made significant inroads into BSNL/MTNL market.

ICT Electronics/Trend addressing PDH, SDH, and SONET technologies got orders for

SDH analyzers and also on the access side, supplied test solutions for ATM,

ISDN, DSL, etc. Fastech, which distributes, Sunrise Telecom’s solutions, is

strong on the handheld side. On the RF side, Anirtsu too has some good

successes. Other majors like Sunrise, Nettest, and Fluke are present through

distributors. Some of the big-time distributors include AIMIL, Aplab, Fastech,

Forbes Gokak, Meera Agencies, Scientific Mes-Tek, VXL, etc. In the BSNL tenders,

ITI has also supplied SDH/PDH products.

n Future

Perfect: With the telecom horizon becoming distinct, the belief is that the

likes of Bharti, Tata, Reliance, and Hutchison, and those like GAIL and Power

Grid are all there for future. It is not possible for them to roll out services

without the T&M vendors. And probably, the service providers will focus on

their core business and leave the measurement and management operations to the

T&M companies. Further, though the telecom operators may be looking for

business within the country, in future they may looking at other opportunities

like looking at handling outsourced back-end operations. One of the most

significant things to happen to the T&M industry, besides the telecom growth

is the joint T&M solution development. All the major vendors, be it the

Agilent, Tektronix, or National Instruments, have software development centres

in India and are working with other global development centres globally. India

could become the test bed.

T&M for Mobile SPs

n QoS: The

Focus: No one is questioning the merits of good service quality. But the

question is the technical pressures. Standards are evolving and hardware

capabilities are advancing. Hardware and software compatibility issues are

becoming more difficult to handle as new technology comes. Today, QoS is more

than guaranteed bandwidth, a clear and continuous signal, and reliable roaming

access. It has been observed that mobile users will use their phones more often,

and stay on the phone up to 20 percent longer, when their calls are not hampered

by noise, echoes, or other interruptions.

n Networks: Problems

with voice transmissions are easy to hear and are very distracting to the

parties on either end of the conversation. The subscriber doesn’t know about

base stations and protocols, he is interested in voice quality. So voice quality

is a major point of emphasis for network quality efforts. Several methodologies

are accepted for managing voice quality in the network like drive tests,

in-service non-intrusive measurement devices (INMD), traffic generation and

analysis.

n Marketing: Marketing

usually has no direct technical responsibility for implementing or enforcing QoS

programs. However, QoS data informs the marketing activity, which in turn

produces meaningful analysis of market trends and subscriber needs. In a

well-run network business, marketing has ready access to the reports and logs

that come out of the QoS monitoring process. Ultimately, marketing relies on

many of the same tools the other departments use to monitor, detect, and

troubleshoot QoS-related issues. The key here is to integrate these tools,

already in place for operations and engineering activities, into the marketing

process such that the data is always current and easily available.

n Security and

Billing: The security and billing activities involves tracking network usage

and the attendant revenues. Both rely on similar processes and tools. The

security activity is chartered with minimizing fraud losses and preventing

illicit network use. The billing group is interested in maximizing revenue from

every legitimate call connection and network signaling transaction.

Many different fraud scenarios are common in today’s mobile network

industry. They range from the opportunistic subscriber who sees a chance to make

a ‘free’ call, to the calculating, systematic usurper of network



services.

Roaming fraud: This is the recourse of the subscriber who concludes

that he or she can get away with making costly international calls for free. It

often succeeds because of the normal 48-hour time span required to exchange

transferred account procedure (TAP) files between networks. By the time the

fraud is detected, the subscriber may be out of reach.

Excessive calls (amount): This type of abuse is characterized by an

‘inappropriate’ number of conversations or call attempts to a risky

destination. This destination may be one that has had problems in the past.

Similarly, there may be an excessive number of calls from a subscriber who is on

a risk list.

Excessive calls (duration): This term refers to the accumulated

duration of calls from a risk-listed subscriber, or to a risky destination. It

also includes the duration of single calls.

SIM Cloning: This is in effect counterfeiting a subscriber’s

identity. It is possible to purchase equipment that can duplicate SIMs, then

program the cloned SIM into a second, or third mobile phone. This phone is used

at the original subscriber’s expense until detected.

Black list: This denotes calls from individuals whose subscription to

the network has been withheld for some reason (possibly for participating in one

of the fraud schemes listed above).

Resolving Interference Nightmare

If one is investigating reports of dropped calls, noisy connections, lost

channels, and poor reception in one of the base station coverage areas, the

equipment at the station checks these. However, something is still corrupting

the communication channels. These could be creation of signals that accidentally

or intentionally interfere with wireless RF signals.

n Interference

Causes:



Improperly Configured Transmitter: Operator X is transmitting on operator Y’s

frequency unknowingly due to a fault or an incorrect setting; and the operator

of the transmitter would be happy to correct it to restore his own service

level. Interference in mobile equipment poses some problems other than that in

base station testing. While most of the same techniques used at the BTS can be

used in the field, there are some limitations. For example, it is not as easy to

disable a channel to clear out intended signals. Most interference is relatively

localized, so the mobiles will have acceptable call quality everywhere except in

the trouble area

Unauthorized Transmitter: Operator X is transmitting on operator Y’s

frequency intentionally in the same frequency band.

Cell Overlap: A cell from network exceeds specified coverage in one or

more channels. Incorrect antenna tilt, excess transmitter power, or a change in

the environment can cause overlap.

Intermodulation from Another Transmitter: Intermodulation interference

can be the result of one or more external radio signals getting into the antenna

feeder coax and entering the offending transmitter’s nonlinear final amplifier

stage. The external signals mix with each other and with the transmitter’s own

signal, creating intermodulation products that appear as "new" (and

often very undesirable) frequency components in the communications band.

OSI Layer 1 and Techniques Audit Parameter Test Instruments Type of Test s Local Area Networks s Twisted Pair Cable length Cable tester out-of-service Near-end Crosstalk (NEXT) Cable tester out-of-service Signal-to-noise Ratio (SNR) Cable tester out-of-service| Attenuation cable tester out-of-service s Coaxial CableCable length Cable tester out-of-service Reflections at connectors cable tester out-of-service Number of nodes protocol analyzer, in-service s LAN Probes s Fiber Optic Cable length OTDR out-of-service Total attenuation OTDR out-of-service Splice attenuation OTDR out-of-service s Wide Area Networks Signal level interface tester out-of-service Signal condition interface tester out-of-service Bit error parameters BER tester out-of-service s OSI Level 1 Stress Tests (at capacity load) Ethernet Network load sent=record CS errors: Collisions Protocol analyzer in-service r Token Ring Token rotation time Beacon packets:jitter protocol of analyzer in-service r FDDI Beacon packets: jitter, wrapping protocol analyzer in-service r ATM Cell BERT SDH frame alarms AIS: yellow alarm protocol analyzer in-service r Protocol analyzer in-service r X.25 CRC error monitoring REJ-packets protocol analyzer in-service y Protocol analyzer in-service Rame Relay protocol tester in-service CRC packets protocol tester in-service s ISDN CRC error monitoring in-service

Intermodulation in a Rusty Fence, Roof: The intermodulation effects from

physical structures such as the rust between the individual roof sections are

difficult to locate.

Intermodulation in Antennas or Connectors: Minor corrosion in a coaxial

connector or the antenna itself can create a fault. The corrosion can act like a

very poor diode and cause just a little bit of intermodulation.

Overload from a Legitimate Transmitter: Sometimes, strong signals from a

transmitter at any frequency can overload a neighboring system. The only

solution is to install a filter on the receiver antenna cable that will pass the

intended signals and attenuate the overload signal.

Adjacent Channel Power from a Neighboring Transmitter: If the allocated

spectrum becomes crowded, there can be some problems too.

Harmonics from Broadcast Transmitters: Also high-powered commercial

broadcast stations can produce substantial energy in harmonics of their signals.

For example, a 5-megawatt transmitter can easily generate 5 watts of harmonics

— more than enough to interfere with nearby mobile communications.

n The

Solutions: Interference can be categorized by its own characteristics. It

can be found at the base station and in the air interfaces with the mobiles.

Interference signals only affect receivers–even when they are physically close

to a transmitter, the transmission will not be affected. The frequency of the

offender is the most common indicator of the source and consequences of the

interference. The solutions lie in hunting for sources of interference in the

networks and fixing them. There are test tools and techniques for managing the

same. The field transmitter and interference tester can be used.

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: - Frame Loss E2 - LineAIS D7 - PathAIS - LineEBE - LineER - PathER Total calls - Idle Calls - Busy Calls HEC Errors Cell Syn Loss Cell BERT Test Cell intersection (o.19)c of cell loss and cell delay>	ER Capacity User Activity Statistics Communications matrix Connections Statistics of completed of failed connection set ups> CRC Errors Transmission Delay Measurements

Measurements at the Base Station Receiver: The best way to hunt for

interference in the base station receiver is to disable traffic on the channel

to be measured. This will assure that no calls are assigned to it and the only

signals that you will see are the interfering ones.

Using Automatic Spectrum Analysis: A BTS tester can be used for this

purpose. There is no need to adjust controls such as resolution bandwidth or

video bandwidth as these are automatically set internally. If the signals are

constantly changing amplitude (as with GSM, for example), one may not catch the

signals at their maximum when you press AutoLevel. If the levels increase beyond

range, a warning banner on the screen will ask to decrease the reference level.

Finding Overlap in the Network: One of the more difficult problems to

resolve is overlapping coverage. If a BTS is located on high ground, its

coverage may unintentionally exceed the engineering plan. If the coverage is so

great that it overlaps a cell that has the same control channel (BCCH for GSM),

then the mobile can no longer distinguish between the two and is put out of

service in the area of overlap. A directional antenna will let you determine the

source of each of the overlapping signals. Moving in those directions will

confirm which of the base stations is causing the extended overlap.

EXPERTS PANEL Vishnu K Goel, managing director, Acterna India and director, South Asia-Pacific, Acterna V Srinivasan, director, South Asia, Tektronix Shankar Roy Chowdhury, marketing manager (India), Agilent Technologies