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MOBILE COMPUTING
From the December 2006 |
UMA in the enterprise by Keith Higgins Enterprises have been awaiting the arrival of dual-mode (Wi-Fi and cellular) handsets that can potentially replace the traditional PBX phone. These dual-mode handsets can make voice-over-IP (VoIP) calls over Wi-Fi, while retaining the functions and benefits of a traditional cellular phone. With these dual-mode handsets, workers only need one device with a single number. The dual-mode handset effectively becomes the “work phone” and allows unlimited mobile voice calls to be made at reduced costs over the enterprise WLAN. When the user moves outside the enterprise campus, the dual-mode handset works just like a typical cellular phone. There are many options to choose from in terms of dual-mode handsets. Many of these dual-mode handsets are based on PDA devices that require proprietary client software to support seamless mobility between enterprise and cellular domains. Although certain enterprises may tolerate the cost and proprietary nature of these devices, others may find it is more practical to consider other types of dual-mode handsets that can potentially have lower price points and are based on standardized technologies. In the near term, the only viable standards-based, cost-effective, dual-mode handsets arriving in volume are those based on unlicensed mobile access (UMA) technology. UMA technology became a part of the 3GPP standard in 2004 and has gathered the support of all major handset manufacturers, including Samsung, Nokia and Motorola. UMA-based handsets have form factors equivalent to today’s cellular phones, despite being multi-radio devices. UMA is generally considered a consumer-centric technology and not viewed as a practical enterprise solution. One of the main reasons that UMA-based dual-mode handsets have not been applied to the enterprise environment is their incompatibility with enterprise IP PBX infrastructure. In its present form, UMA technology relies on the cellular core network to provide call processing and calling features to UMA handsets. As a result, enterprise calling features are not available on UMA handsets. Ideally, an enterprise worker should be able to use a standards-based form factor dual-mode device such as the UMA handset as his “anywhere” office phone. This means enterprise calling features such as call groups, extension dialing, multi-ring and follow me should be accessible by the UMA handset when in the enterprise environment. All existing enterprise IP PBX calling features should be accessible on that UMA handset. The UMA handset should become an extension to the enterprise IP PBX whenever it enters the coverage of the enterprise WLAN. This way, not only does the enterprise worker enjoy unlimited voice calls over Wi-Fi at reduced costs, all enterprise calling features traditionally only available on fixed PBX phones are now extended to the UMA handset. Once this is achieved, enterprise workers need just a single handset for both cellular and enterprise needs. Investment in fixed VoIP phones can be capped and substituted by UMA handsets. In order to achieve this type of enterprise feature integration, a new type of network controller is needed to allow enterprise PBX infrastructure to extend enterprise-calling features to UMA handsets. This network controller would effectively allow the enterprise PBX infrastructure to provide call control to UMA handsets, as opposed to the cellular core network. In doing so, the UMA handset becomes closely coupled with the enterprise infrastructure, allowing robust enterprise feature integration. In addition, this type of network controller would also enable seamless handover between enterprise WLAN and cellular network domains. This type of solution should also address security and quality of service assurance requirements of enterprise domains. Interoperability with enterprise WLAN infrastructure is also critical.
Keith Higgins is Vice President of marketing for Stoke, Santa Clara, Calif. |