XPIC Technology Allows Increased Capacity

Carriers continually have to grapple with capacity issues, and these issues will only become even more critical as mobile users become attached to data applications. To help operators serve those high-capacity needs, Irving, TX-based NEC America, Inc., Microwave Radio Group, has introduced its cross polarization interference cancellor (XPIC) technology, which allows service providers to carry as much as two OC3s on a single frequency pair by using both horizontal and vertical polarizations.

This is significant because without such a technology, engineers were stuck in an either-or situation. Trying to take advantage of both polarizations would lead to cross-polarization interference. The technology negates that interference, thus allowing the carrier to transmit twice the data it could previously. This means that by using all eight channels and configuring them all with the XPIC technology, a carrier can transmit as many as 16 155 Mb OC-3s, or 2.6 Gb of data, in the 6 GHz band.

Instances when this technology might come in handy include high-capacity routes—backbone routes with lots of feeder traffic. Often carriers will use radios where fiber doesn't reach, such as remote areas, mountainous terrain, or around water, said Becky Holland, NEC America Microwave Radio Sales – Western Region, and with the XPIC technology, the radios can come closer to what fiber offers. "It doesn't even have to be remote locations, just areas where fiber isn't available," Holland said.

The technology also helps carriers boost capacity in congested areas. For example, if engineers are unable to clean off all of the frequencies because of high interference levels, they can employ the canceling technology to get more capacity out of the frequencies they are able to use.

The XPIC technology is an optional feature for the NEC 3000 series radio, as well as on the 2000 series, and carriers can take advantage of the capacity jump without giving up a lot of space. A full complement of radios—implemented in a 2X14 configuration—fits into four bays, Holland said.

By Ellen Jensen, Managing Editor, Wireless Networks Online