Testers try to tame HSDPA

High-speed downlink packet access upgrades might be the next big thing for GSM-based mobile carriers looking to support more bandwidth and new applications, but assuring network performance and service quality over these networks won't be an entirely new adventure for test vendors such as Spirent Communications.

“If you have field experience testing [CDMA 1X] EV-DO, that's something that easily translates to HSDPA,” said Lachu Iyengar, project manager performance analysis, wireless for Spirent. “It's a performance-sensitive technology in which the user experience could vary widely based on where the user is in the network.”

Because HSDPA is a rate-adaptive technology, with bandwidth availability high for some applications and lower for others, network operators can't just rely on a “fat pipe” to guarantee a quality user experience, he said.

Carriers such as Cingular Wireless and O2 recently completed successful HSDPA test calls, which is considered an important step in determining how their services will behave in a commercial environment. The test calls typically involve calls being placed under ideal, low-load network conditions, followed by other tests that gauge network performance as impairments, such as fading, are introduced.

Spirent officials believe many carriers eventually want to offer mobile data service level agreements(SLAs) to corporate customers — a daunting notion, but also a requirement for competing in the increasingly competitive world of broadband services.

“SLAs will happen sooner rather than later,” said James Brunson, Spirent product marketing manager of mobility solutions. “If I'm going to rely on a mobile carrier for broadband access, it should be as good as wireline.”