5G Spans Last Mile to Handset

Article By : Rick Merritt

5G will start off as fixed-wireless access and slowly move into the handset, said an Ericsson engineer who ran the numbers at Hot Interconnects.

SANTA CLARA, Calif. – 5G cellular will start with fixed-wireless services, lead to big changes in smartphones and ultimately rack up some staggering numbers, according to a keynote from a senior Ericsson engineer.

Verizon and AT&T have already announced plans to use 5G at 28 and 39 GHz as a last-mile access technology starting late next year. “It will be easier to plop a pole in a neighborhood than connect homes via fiber,” said Dave Allen, a distinguished engineer at Ericsson speaking at Hot Interconnects last week.

Thanks in part to such services, Ericsson expects by 2027 more traffic will run over wireless than wired nets. The initial 5G fixed-wireless services will act as neighborhood extensions of carriers’ core LTE networks.

The collaborative 4G/5G roll out is different from the past, in part because pure 5G requires a fair amount of heavy lifting.

For example, millimeter wave transmitters and receivers will need to use massive MIMO antennas with beam forming on both sides. The techniques compensate for about 40 dB signal loss leaping from traditional 3 to 5G 39 GHz radios.

At those frequencies, interference can come from “radio passing through my body, flocks of birds and trucks driving by…there’s 10 million times higher loss than on wired nets,” Allen said.


5G services aim to cover the waterfront. Click to enlarge (Image: Ericsson)

He described massive MIMO as “a form of spatial multiplexing…assigning multiple low speed signals to different antennas in an array, [with bandwidth] limited by the smallest number of antennas on either end.”

Beam forming was first described in 1905. It uses constructive interference techniques that don’t work that well in lower frequencies.

MIMO and beam forming together help maximize spectrum reuse. “When you have a scarce resource, you can afford to throw a truckload of math at it,” he quipped.

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