Breaking the Mold

A new generation of data services means many of the old T&M techniques are no longer adequate.

Migrating to 2.5G and 3G requires new handsets, new equipment and new software. But what about T&M equipment? As networks expand to accommodate packet-switched data, carriers not only must test a slew of new services, but T&M vendors also must step up their equipment's capabilities.

QoS tops the list of new elements that carriers must test in their next-generation networks. In voice networks, QoS simply meant coverage. Now, QoS means something else completely, said Pierre Lynch, Tekelec (www.tekelec.com) senior product manager for the diagnostics division. Once they have 2.5G and 3G, carriers can sell customers different degrees of QoS, depending on the customers' requirements. Customers will pay for services that guarantee specific bandwidth, so carriers need to tune their systems to offer various levels of service.

Users only need a 16kb/s connection to make a voice call through the mobile network, but then you have power users who have to get on MapQuest.com while traveling 80 mph to get directions to their business meeting, added Wayne Newitts, Tektronix (www.tek.com) market segment manager, communications. Those people will require the 170kb/s, 300kb/s or 2,000kb/s services that are theoretically promised in these next-generation services.

Newitts said that next-generation testing tools will allow carriers to guarantee bandwidth in certain regions, too. For example, one area of a city may include power users, but another area may consist of people who rarely use high-speed mobile Internet connections because they access the Internet from their PCs.

These people are not going to be trying to suck down 2Mb from you all of the time, he said. So you have a whole new layer of complexity in planning and in delivering these variable levels of QoS, and it is a challenge for operators to verify the real-time dynamic levels of QoS.

Additional Elements

Outside of QoS, other elements must be tested as carriers move to 2.5G and 3G. Dave Adams, Acterna director of wireless technology, said it's important for carriers to ensure that data calls complete and that they bill those calls correctly (www.acterna.com).

Right now, carriers get all of their billing information from switches, but soon they will get it from data nodes, switches, content providers and gateways, he said. There are about 10 different points in the network from which they will gather billing records, so it's phenomenally complicated.

Newitts pointed out that 2.5G and 3G introduce IP into the mobile world; therefore, IP must be included in all next-generation test equipment.

You have to support both packet and circuit-switched testing technologies in the same test box, he explained. Whereas there was a fairly sharp division up to a year ago between telecom and datacom tests, as IP enters mobile communications, that defining line has gone away. There no longer will be datacom or telecom test solutions there will be communications test solutions that almost in every case include IP competency or capability.

In addition, next-generation wireless networks require test equipment to address new protocols, Newitts added. For instance, a customer may originate a call in a 3G packet-switched network, but it might terminate in a circuit-switched network. Test equipment must be able to give carriers a view into the packet-switched voice call, but also follow it as it translates into a circuit-switched call. Ideally, carriers should be able to use a single test solution that correlates information from packet-switched and circuit-switched networks.

If you provide part of that solution, or both halves, but you don't join them in the analyses or information your test equipment provides to the carrier, you are not giving them what they need, Newitts said.

Changing Equipment

As carriers prepare for next-generation networks, test equipment must change, too. Wayne Dewey, AEA (www.aea-wireless.com) owner, said that 2.5G and 3G services will operate in a much higher frequency range than cellular and PCS systems, so test equipment must accommodate those frequencies.

I don't have any test equipment in that 2.8GHz region, and if I am going to stay competitive, I need to do that, he said.

Dewey said he plans to get test equipment that can accommodate spectrum in the 1.5GHz-to-3GHz range by year-end. In the meantime, he has developed test equipment that works at 700MHz, spectrum that carriers possibly could use for extra capacity in 3G networks.

Adams said carriers have three options for their test equipment once they deploy 2.5G or 3G networks. Some equipment only will require a simple hardware or software upgrade. Other times, carriers can stay with the same vendor, but trade in their 2G equipment for new tools that handle 2.5G and 3G. Or, carriers face the possibility of buying entire new sets of equipment that they have never bought before, such as protocol analyzers or IP analyzers.

T&M vendors are updating their products, too. Acterna is changing two aspects of its AirAudit product to make it 2.5G- and 3G-compatible. The product includes a wireless handset inside a box, which carriers can place in areas they normally would drive test. Rather than sending out teams of people to drive test around an area, through AirAudit, carriers can automatically command the handsets to make calls. The product currently tests voice features, including 3-way calling, call waiting, call forwarding and voice mail. However, data will require carriers to test 10 times the amount of features, Adams said.

They are remote boxes, so you stay home to test, and it includes scripting so you don't have to be there and scheduling so you can automatically check what worked and what didn't, Adams said. You can run the test all night, see what worked and then check bills.

Support aspects, such as scheduling and scripting, will stay the same. However, the new version has different RF interfaces built into it. Plus, it can handle new applications and test new services, including data transactions.

I was able to use this remote test system to simulate what a user would go through to purchase a pair of shoes, he said. Did it work? What was the performance like? What were the delays? Then we can check the billing records and ensure a user gets a certain data rate. If they don't, we can test to see if they receive error messages back from the network.

Tekelec is developing diagnostics equipment that helps carriers test QoS. Carriers will be able to place Tekelec's simulators and testers in their networks and then test three quality levels. Based on the statistics and measurements that the tools provide, the carriers then can tune their networks by adjusting the controls to affect the QoS for different classes.

The carriers can define three QoS levels, then use our tool to simulate their network, Lynch said. We can tell them, based on the result, if those three levels are behaving the way they expected them to behave and if they need to tune them and then test again.

Lynch said Tekelec also has had to adapt its hardware for 2.5G and 3G. It has built its new I3000 hardware platform specifically for next-generation systems. If a carrier already uses the company's I2000 signaling-load generator, it will have to upgrade the hardware.

To us, it is a brand new series of products, and we needed a brand new hardware system to support the high load rates required by 2.5G and 3G, he said.

Newitts said Tektronix's K12 series of protocol-analysis platforms will need a software upgrade in a 2.5G or 3G world. In some cases, carriers also may need additional hardware, but Newitts said the hardware is a board that easily plugs into existing platforms.

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Harter (betsyharter@aol.com) is a freelance writer based in Athens, GA.