Enter smart and ultra-broadband antennas
Equipment vendors are trying to respond to the spectrum crisis in the short term by ramping up support for all the potential LTE frequency bands. But the work poses challenges, especially in antenna design both in handsets and towers, said speakers here.
“Antennas are becoming a really big problem because of space in the handset,” said Joon Hoo Park, a senior vice president of standards and technology at Samsung Electronics. “Lack of space is a problem as is signal coupling interference between bands, especially in band 13,” he said.
“There are no global [base station] antenna standards out there now,” said Kevin Linehan, chief technology officer for antenna systems at Commscope.
Linehan also chairs an NGMN working group drafting a white paper on recommended standards. Mobile data demand is driving an increasingly rapid pace of technology development for antennas some of which cover as much as a GHz in frequencies, he said. “That’s been a real challenge to achieve,” he added.
Beam forming and MIMO techniques are rapidly being adopted in products. Smart antennas that can track a handset signal and null out interference also are in the works. Further out, vendors are studying ways to integrate flexible base station antennas into park benches and lamp posts, he added.
Powerwave has already deployed hundreds of thousands of so-called ultrabroadband base station antennas that cover frequencies from 700 MHz to 2.7 GHz, said Khurram Sheikh, chief technology officer of Powerwave. The company is also testing at its headquarters active antennas that put transceiver electronics behind each antenna element.
“We are seeing an average 2 dB gain and a standard deviation 3.5 dB at the cell edge,” he said. “The uplink results are a 4.3 dB gain and a standard deviation 2 dB,” he reported.
“That can really improve the customer experience, so we think the standard going forward is an active antenna,” he added.
Taking another tack, Huawei engineers described a prototype base station for running LTE over TV white spaces spectrum from 470 to 806 MHz. The approach will require new handset silicon with adaptive filters spanning 300 MHz of spectrum without using SAW filters.
“This year we hope to get the prototype into field trials with carriers,” said a Huawei engineer.