The most prevalent and successful wireless technologies are all cellular. Cellular carriers are scrambling to provide fast, efficient IP transport mechanisms across the various cellular networks. But therein lies a lot of the problem. There are multiple cellular networks globally with multiple connectivity and transmission protocols. To successfully provide global wireless VoIP coverage requires recognizing and understanding tens of protocols – all at the same time if you want proper roaming and seamless handoff from network to network.

WiMax, a microwave-based WLAN technology holds promise – it can be made to operate as simply as WiFi and has a range of a few miles. But it isn't fully ready for nationwide/global rollout. There is ClearWire with its wireless broadband access technologies that are being rolled out in Stockton that are fast enough to handle VoIP readily. There are other still faster technologies that are a few years further away that could solve wireless bandwidth issues and handle converged multimedia wireless communications.

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