Basically, I see wireless VoIP following the same path as wireless data - standardization, price drops, consumer adoption, behavior change, and, finally, enterprise adoption bolstered by users.
As for VoIP protocols, SIP is emerging as a fairly dominant standard, particularly overseas in places like Japan. 802.11 is the undisputed champ for obvious reasons, and the quality of service standard, 802.11e, promises to help voice reliability in small, consumer deployments. Domestically, this has created a pretty substantial price drop in handsets that are capable of wireless VoIP - generally below the $200 range, meeting the $199 magic price point, i.e. the price where hockey-stick growth is possible. Those prices will drop an additional 40% to 50% by 2006 to around 99 bucks (when you go below $100, it changes from "dollars" to "bucks"), as more advanced products, such as Wi-Fi Blackberries become available.
In late 2004, consumer service providers are announcing wireless SIP phones as a new service - note recent announcements by Skype, Net2Phone, Vonage, and, most importantly, Cingular. This is important because once consumers can afford reliable wireless VoIP services and start using them, the pressure to support these services in the enterprise will mount, because once wireless anything is used, behavior changes and its hard to go back (i.e. cordless phones, cell phones, wireless laptops, my Bluetooth mouse and keyboard, etc.)
Businesses have many reasons that financially justify adopting wireless VoIP and most are evaluating it as a strategic part of their network infrastructure. Ultimately, WLAN vendors will need to focus on enterprises and their unique problems. But when the decision makers actually get to use the consumer products, they will really begin to picture the business advantages of doing this for their entire enterprise and this will bolster adoption in the enterprise. Even though it's been talked about for over a year, wireless VoIP (or VoWLAN) has only recently reached its magic price point.
Joel Vincent is the Director of Product Marketing for Meru Networks Inc., the leader in wireless LAN performance, where he leads efforts in defining, driving, and evangelizing Meru's technology for voice over WLAN. Prior to his role at Meru Networks, he played instrumental roles in the founding of the INS EnterprisePRO (now Lucent Netcare) network management software product line, the founding of the NETGEAR consumer and wireless product lines, and introducing the first commercially deployed voice over DSL system at CopperCom Inc. He has successfully brought over 60 products and services to market worldwide, garnering many awards ranging from Comdex best-in-show to a nomination for a ComputerWorld Smithsonian award.
Joel has written about wireless VoIP for numerous publications including Internet Telephony, Telephony Online, Wireless Business Review, Converge Network Digest, Business Communications Review, and Wireless Systems Design. He combines over 12 years of experience in the data communications industry with his BSEE degree from the Massachusetts Institute of Technology (MIT) to provide a practical technological voice to the wireless networking industry.