LTE Not Well Suited to High-Frequency Spectrum, Meeting Needs of IoT, Technologists Say
As the wireless industry contemplates the use of high-frequency spectrum, it needs to develop technology beyond LTE, Michael Peeters, Alcatel-Lucent chief technology officer-wireless technologies, said Thursday on a 4G Americas webinar. LTE isn't well suited to “millimeter-wave” spectrum, Peeters said. “We need to think about coverage and making sure that 5G can reuse 4G capacity as well, so we definitely need a new waveform to be able to span both the high and low frequency bands as well as having high-speed mobile broadband.”
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LTE also isn't ideal for the IoT and machine-to-machine communications, Peeters said. “As the IoT tsunami will hit us in the coming years, that will start to decrease the average spectral efficiency of LTE and we will need something new.” LTE also is limited in other ways, he said. For example, some public safety or vehicle-to-vehicle communications require “much shorter round-trip times” and a “connectionless mode,” he said. That's something that can't be “reverse engineered” on LTE, he said.
Use of bands of 30 GHz and above create technical and deployment hurdles, said Mike Murphy, Nokia CTO-North America. “I do believe they’ll get resolved and the work to do that is progressing,” he said. The high-band frequencies degrade quickly and require line-of-sight or “near”-line-of-sight connections, he said. If that’s not possible, a device needs to be able to connect to more than one base station to maintain connectivity, he said. One big question is how to install enough base stations, he said, saying even for LTE, that's proving difficult. “So we need to find a way to make that cost-effective," Murphy said. “There are lots of challenges, but I think we’re going to solve them.”
Technologies including mass multiple input multiple output and beam forming are still in research but will help, Murphy said. “The challenge now really is to create practical, cost-effective, implementable products and that’s going to take some time,” he said.
The Internet initially was about the exchange of content between static endpoints, said Mike Recchione, Cisco principal engineer-mobility. Then companies had to start worrying about mobility and then security. Now there's a “huge burgeoning” of content that has to be delivered, Recchione said. “The end-to-end model of the Internet just makes the amount of traffic that we have to carry … huge,” he said.
Chris Pearson, president of 4G Americas, noted the huge buzz around 5G. “Some people question is this the right time to talk about it,” he said. “My answer is yes. If you look at the evolution and revolution of technology over time it takes a long, long, long time to get it right.” The timing is right for planning, collaboration and cooperation, he said: “That’s why you see organizations such as 4G Americas working so diligently in the 5G space.” FCC Chairman Tom Wheeler recently said the FCC will soon release an NPRM as it continues its examination of how new developments in technology could increase the viability of operations in bands above 24 GHz (see 1508030071).