Handset Health

Wireless carriers bear great expense to ensure that their RF networks are functioning efficiently. But what about the other half of the network -- the mobile stations? Historically, carriers have not had sufficient tools to monitor wireless phones on an ongoing basis, which has cost them a lot of subscribers.

Carriers lose about a quarter of their subscribers per year, and according to a recent study by Andersen Consulting, 30% to 40% of this churn is due to concerns about call and network quality, which can be high among high-value subscribers. Partnered with the statistic that 80% of a carrier's profit is derived from the top 20% of its subscribers, this means that subscriber satisfaction with call quality is a significant driver of carrier profitability.

According to carriers' technical support managers that are responsible for diagnosing subscriber call-quality complaints, one-third to one-half of serious call-quality problems are due to poorly performing wireless phones. Although carriers do not, in most cases, own the wireless phones, their subscribers hold them responsible for the performance of those phones, and although phones break and drift out of spec, subscribers do not know whether that poor call quality is due to problems with the phone or the network.

Poor call quality can lead to "leakage," where the subscriber changes his wireless phone usage patterns to reflect a diminished confidence in the service usefulness. The decreased usage results in revenue loss to the carrier, and, in many cases, the customer terminates the service.

HISTORICAL REMEDIES Although carriers have long been aware of the problem of poorly performing phones on their networks, there has been little that they could do about it. To date, the only reliable way for a carrier to check whether a phone is in good working order has been to put it on a bench tester. Because there is no one time when each subscriber comes back in to a distribution outlet, there is no one time when a carrier can check each subscriber's equipment. Likewise, it would be cost-prohibitive for a carrier to send a van with test equipment out to each subscriber.

Another alternative for attempting to identify poorly performing phones is by using existing dropped- call reports. Because carriers' existing switches report dropped calls, the dropped-call report gives the carrier the ability to see which subscribers are having calls dropped more frequently than average with minimal expense. However, data from dropped-call reports alone is unreliable because a wireless phone that is reported as dropping a lot of calls may simply make a disproportionately large number of calls, may operate often in areas of poor coverage or may have been cloned.

To deliver good call quality, a carrier needs to have centralized, automated monitoring of the entire base of wireless phones -- without having to physically touch the phones.

Such a transparent, "active," system requires hardware that is capable of analyzing multiple aspects of the handset signal during transmission. A convenient method of doing this is to leverage data from an RF-fingerprinting fraud-prevention system. An RF- fingerprinting system consists of radio frequency units (RFUs) at each base station that examine the characteristics of the reverse control channel when the call is set up to detect cloned phones. To differentiate similar handsets from one another accurately, detailed and accurate information must be gathered and analyzed by the RF-fingerprinting system. Some of this information is directly related to phone performance and can be extracted from the RF-fingerprinting system to generate a "health profile" for each handset.

Modern active handset health-profiling systems collect data from the RFUs transparently and compile it in databases on a daily off-peak schedule, keeping data current while minimizing interference with other network activities. The data then is delivered to the user's desktop for integration into a customer-care system.

Armed with this performance data, customer care can leverage its existing inbound customer-care programs to better field incoming calls from subscribers complaining of poor call quality. Carriers also can target subscribers with out-of-spec handsets and develop valuable outbound calling programs to pinpoint and eliminate problem phones.

Health profiling applications' graphical user interfaces provide the carrier's existing marketing, customer-care and engineering departments with functions to support targeted outbound marketing programs, inbound (611) call response in technical support and application management. The carriers have access to daily lists of phones with bad health, which then can be ranked and viewed by criteria such as health rating, MIN or handset manufacturer.

Pro-active contact is essential to saving at-risk customers and extending service contracts. Active handset health systems supply carriers with the data they need to contact customers with bad phones -- even before the customer is aware of the problem. Because these bad phones can be identified and eliminated, network quality is optimized, further improving call quality for all subscribers.