As CommScope’s Comsearch division performs spectrum management at the WiMAX World trade show in Chicago this week, there are some differences from past trade events.
This year’s show will feature 15 live demonstrations. Just like last year, most of the demonstrations are in 2.5 GHz spectrum, owned locally by Sprint Nextel.
But unlike last year, Sprint’s mobile WiMAX network known as Xohm is on the cusp of production status, not just in a test phase. That makes avoiding interference much more challenging, explained Laura Fontaine, director of spectrum management at Comsearch.
“This typically isn’t something you would normally see. It’s like a small city inside the convention center,” Fontaine said. That comes with lessons for the real world. “You’re always going to have adjacent channel neighbors, adjacent market neighbors that you’re going to have to coordinate with to make things work. But it’s certainly more spread out and more diverse outside. In the real world, you’re certainly not going to have an intermediary between the companies,” she noted.
Another factor each year is the sudden gathering of so many consumer electronics in one place. Each year, the devices get more data-intensive, but Fontaine said the industry shouldn’t be overly concerned about interference from them. Interference is only likely when a large number of consumer electronics are in close proximity to a large number of unlicensed spectrum devices such as Wi-Fi routers, she and other Comsearch engineers said.
Comsearch and Sprint began coordinating in June. Comsearch will use most of the same techniques as at last year’s show, such as limiting power, precisely tuning antenna directions and keeping exhibitors to a strict schedule, Fontaine said.
A bigger change is likely to happen at next year’s show, when Comsearch may use new technology to automatically synchronize the data flow, she said. In that process, base stations and subscriber devices will transmit only at specific intervals, based on industry standards in commercial-grade GPS antennas.
When companies use the synchronization method for commercial networks, it will save money because of decreased requirements for filtering, guard bands and other mitigation techniques, a Comsearch white paper explains.
But something that will be an issue, at least on the trade show circuit, is LTE technology. For now, WiMAX and LTE are in distinct camps, often considered rivals because of their backing companies. However, the technologies have the potential to merge someday and it’s much more difficult to borrow high-bandwidth PCS spectrum needed for LTE than that of WiMAX, Fontaine said. Instead, LTE vendors at the recent CTIA show used more readily available AWS spectrum.