EV-DO Success Could Forestall EV-DV
By Carlo Longino, Wed Sep 29 23:15:00 GMT 2004

The next upgrade to the CDMA 1xEV-DO standard could deliver sufficient bandwidth to support voice over IP and curtail the need for the faster EV-DV standard.

Verizon Wireless' chief technical officer, Dick Lynch, told the CDMA Americas Congress that the operator is pushing its vendors to support the forthcoming Release A upgrade to EV-DO, which delivers theoretical speeds of 3.1 megabits per second on the download and 1.8 megabits per second upstream. The increase in upstream rates means that carriers could conceivably use it to offer voice services over IP, getting around one superiority of the competing 1x standard EV-DV.

One of the benefits of EV-DO is that it uses a separate 1.25-mHz channel to carry data, so when voice traffic picks up, speeds aren't impacted as on other networks that prioritize voice. This, of course, takes a stripe of spectrum away from carriers' voice services, and EV-DV is more efficient in that it doesn't force carriers to dedicate a data-only channel. But Release A adds the VoIP support and quality-of-service capabilities that can prioritize voice packets. With these additions, carriers could see little need to utilize EV-DV, which uses circuit-switched voice, instead of an all-IP EV-DO system, particularly since the possible downlink speeds are the same.

The telecom world is going all-IP, and mobile carriers' desires are no different from wireline operators in this regard. While EV-DV may offer more voice capacity and more efficient use of spectrum, EV-DO offers two significant advantages: EV-DO equipment and devices are already shipping and commercially proven in several countries like South Korea and Japan, and it looks to have the quickest path for CDMA carriers to an all-IP network. Of course, standards development doesn't happen in a vacuum, and companies backing EV-DV are also working on making VoIP support a key part of their offering. But any switch to an all-IP mobile network is still quite a ways off.