Voice comesto the WLAN

Voice service is the latest WLAN capability making inroads in the enterprise market

A wireless local area network (WLAN) capability making inroads in the enterprise market is voice service. The supported features—PBX extension, roaming throughout the business campus and LAN-to-cellular roaming while accessing data such as e-mail and Internet—are of particular interest.

Wireless voice is not a new concept in the office and has been proposed by incumbent equipment vendors in the past. Ericsson and Nokia for example have proposed GSM as a convenient solution for using a single phone. Cisco also offers an enterprise solution (CallManager) that allows phones to interface with LANs. Currently 802.11 products are available for office environments to allow cordless phones to access WLAN networks, thereby enabling communications inside the office and between offices. Cordless phones interface with a WLAN base station, which is in turn connected to the LAN. The base station digitizes and transmits the signals received from the mobile phones over the IP network. The setup also involves a server for switching and call control.

However, voice over WLANs (VoWLANs) is not a mainstream enterprise play, but is more targeted at specific vertical industries such as healthcare and manufacturing. They are usually deployed by companies that already have mature WLAN networks in place. In the near future however, enterprises will start seriously evaluating the technology, mainly to converge the wide variety of networks, devices and infrastructure.

Currently the greatest hurdle for IP VoWLAN products is that they are usually developed using proprietary voice technologies. Often VoIP signaling protocols used on the LAN differ from vendor to vendor. Secondly, voice QoS is still an unresolved issue. Some major vendors, predominantly SpectraLink and Symbol Technologies, today offer proprietary VoIP prioritization capabilities to enable VoIP QoS over an 802.11b LAN in the absence of a QoS standard. The IEEE is currently in the preliminary process of developing a specification, 802.11e that would add voice and quality of service protocols to the standard.

Various interesting VoWLAN-based applications appeal to different verticals. Vocera Communications, for example, is releasing a product called the Vocera Communications Badge that uses the 802.11b technology in a wearable, voice-controlled device that operates on a wireless LAN. Employees wearing the badge around a building or a campus environment can instantly communicate with others. The badges also give users the ability to move throughout a building, roaming from one subnet to another without disconnecting and to connect to the organization’s PBX for placing calls. These are ideal features for medical facilities, retail operations or warehouses.

Another notable enterprise application is the use of softphones. SymPhone is a client/server software solution from Telesym that turns any 802.11-enabled device running Microsoft Pocket PC into a mobile phone and allows companies to overlay a cellular-style network onto their existing WLAN infrastructure. In other words, it allows users to make calls from personal digital assistants (PDAs) equipped with speaker and microphone. The SymPhone technology eliminates delays by giving voice packets priority over data on the network, and it produces very high-quality sound. SymPhone is currently targeted at companies with mobile workers such as retails stores.

Mitsubishi Electric has developed an IP cellular phone that enables the users of both fixed line and cellular IP phones (which use the proprietary HCAP protocol) to communicate over the Internet. There is also a worldwide movement afoot to make the PocketPC (or PDAs in general) the universal communications device. Microsoft and an array of Japanese electronics manufacturers including NEC, Sony, Casio, Mitsubishi, Toshiba and a number of Taiwanese manufacturers are already in this market. The European cellular operators including mm02 and T-Mobile are already offering the product to increase usage of their GPRS networks.

Despite the advances made in the VoWLAN area, standardized dual-mode cellular and WLAN phones have not hit the market yet. The primary reason is the fact that the WLAN chipset adds considerable cost to the handset and has a significant power drain. Bluetooth may be perfect as the local area element, since its chipsets are significantly cheaper and drain less power from the battery.

The most promising VoWLAN announcement came in late 2002 when Motorola announced it will collaborate with Avaya and Proxim to push VoWLANs, especially in the enterprise. Motorola will provide the dual-mode phones, Avaya the SIP-based VoIP software, and Proxim the WLAN equipment. Enterprises will be billed regularly for corporate-based WLAN calls, but will revert to cellular billing when in the WWAN territory. Voice-enabled Wi-Fi WLAN infrastructure from Proxim and SIP-enabled communications applications from Avaya is expected to be made available early in 2003. Trials of the joint solution are expected to begin in the second half of 2003.

Goli Ameri is the President of eTinium, Inc., a telecom consulting and market research company specializing in wireless and switching technologies. She can be reached at gameri@etinium.net or (503) 968-8437. For more information on other areas of the WLAN market, please refer to eTinium’s recently released on Seamless Mobility: The Marriage of 3G and Wi-Fi.

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