LTE NA: Analyzing antennas, sifting through signals

DALLAS – Antennas and network signaling in LTE were the highlighted topics as the LTE North America conference got underway this week, underscoring the complexity of the LTE network and its continuing evolution.

Michael Thelander, CEO of Signals Research Group, presented some of his company’s data on the impact of multi-input, multi-output antennas on network performance. In recent testing done in Texas, he said that comparisons between 2×2 and 4×2 MIMO showed significant improvements in speed in the uplink, particularly at the cell edge. And time spent at the edge of cells isn’t insignificant – accounting for 32% of time spent on the network in SRG’s testing.

Thelander said that SRG’s tests showed that 4×2 MIMO did demonstrate improvements in network efficiency and speed as well as battery life in the testing, which focused on constant transmitting. Some of the battery life improvement was directly related to better network performance, he noted.

“If you’re trying to upload e-mail or a YouTube video, the faster you can do it, the faster you can turn your radio off,” Thelander said.

There is a certainly a lot of uploading and downloading going on. Jim Parker of AT&T’s antenna solutions group told the LTE North America audience at the antenna event that AT&T has seen wireless data traffic rise 50,000% over the last seven years, and that 81% of the carrier’s customers now have smartphones.

Parker noted that macro sites are “still the most efficient way to reach the most people possible” and that AT&T has already met its 2014 goal for covering 300 million potential customers with LTE. The carrier also is beginning to deploy LTE-Advanced in the form of carrier aggregation in some markets.

Parker said that one particularly important development in network infrastructure was the move by Alcatel-Lucent and TE Connectivity earlier this year to shift to a CPRI interface for distributed antenna systems. That development, he said, means the expected savings in DAS can be as much as $70,000 per site by cutting the amount of space and equipment needed.

Small cells take a turn at LTE North America

Another familiar network player was being discussed on the signaling scene: small cells.

Andy Germano, VP of the Small Cell Forum, spoke to the LTE North America audience on the signaling impact of small cells on the network.

The gains that are expected for small cells are significant. Germano cited one study which found that with as few as four small cells per macro site, more than 50% of the macro’s data traffic could be offloaded, with a 467% improvement in user experience.

“You don’t need a lot of small cells to see a big impact for your network,” Germano said.

The architecture for the small cells has a significant impact on the signaling load, he said, for instance, whether or not a small cell gateway is used and whether it aggregates some or all of the related traffic.

A significant part of the signaling discussion centered around the role that network function virtualization is starting to play. Hear more about NFV in an interview with Emil Olbrich, VP of network technologies at SRG, who led the signaling event discussions.