Seen at the China Mobile's booth at the Mobile World Congress in Shanghai is Qualcomm's prototype 5G base station. The FPGA- and DSP-based system is regarded as one of the early efforts to test ideas expected to emerge in 3GPP standards that won’t start to gel until 2018.

The news comes on the heels of the 3GPP finalising standards for an ultra-low power version of LTE for the Internet of Things. With new IoT specs out, support is growing in 3GPP to accelerate the pace of getting out a first phase of 5G standards focusing on mobile broadband applications, likely saving 5G IoT specs and other issues for a follow up second phase, expected about 2020.

Qualcomm revealed two key features its 5G New Radio (NR) prototype will support. They include channel bandwidth wider than 100 MHz to fuel 3+ Gbit/second data rates and integrated subframes that could deliver transmissions with latency as low as a millisecond.

The Qualcomm system is geared to run over bands from 3-5 GHz. Qualcomm announced earlier a separate prototype system for 28 GHz as a toe in the water for 5G systems that could someday span 28-60 GHz or more.

The 3GPP has been hearing proposals for 5G air interfaces since April with plans to start winnowing out favored approaches by early next year. Channels wider than the 20 MHz links in today’s LTE are widely expected in the final 5G spec. The channels are expected to be combined with antenna arrays and higher order modulation schemes to deliver faster data rates.

To cut latency, 5G also is expected to integrate uplink and downlink communications into unified data frames so that acknowledgements, for example, are automatically sent after transmissions are received. The approach could cut latency to one millisecond from 8 ms currently on LTE. The speed up enables new uses including what’s called network slicing or letting a link quickly switch between multiple shared applications.

John-Smee-with-cap Figure 1: John Smee, VP of engineering for corporate R&D at Qualcomm.

“We are tracking 3GPP and as it makes decisions new features will come into the prototype,” said John Smee, a vice president of engineering for corporate R&D at Qualcomm.

Support is growing in 3GPP to start the 5G work by putting in place the ingredients for higher data rates, such as the wider channels and redesigned subframes, Smee said. Other related pieces likely to get defined early include details for massive MIMO antennas, more efficient channel coding schemes and support for spectrum bands both below 6 GHz and above 20 GHz, he added.

Details related to mission-critical and IoT services are likely to be pushed to the second phase of 5G standards, he said. Qualcomm believes 5G will support a variety of transmission timeframe intervals for different kinds of wireless services.

“We are trying to expand the ecosystem,” said Smee. 3G and 4G were pretty straight forward more efficient services for the same market, but the goal for 5G is to enable new business models, product types and form factors like VR headsets--we are trying to create a flexible standard that adapts to different scenarios,” he said.

Ericson rushes out 5G prototypes

Qualcomm is not alone in bringing out early 5G prototypes focused on the future of mobile broadband.

Last week, telecom systems maker Ericsson announced plans for software plug-ins to upgrade carrier systems to 5G-like services in five areas --massive and multi-user MIMO antenna arrays, latency reduction, virtualisation of radio-access networks and smart routing. The code will be production-ready next year.

The software rollouts will be staggered with field trials of antenna arrays with 16 or more transmitting elements starting this year, said Antti Keintola, a portfolio manager in Ericsson’s radio group in an email exchange. Ericsson already has a 5G Radio Test Bed and Radio Prototypes deployed and in field trials in Japan, Korea, Sweden and the U.S. with peak downlink throughput in some cases of more than 25Gbits/second, he noted.

Learn how the latency-reduction software could cut by half typical latencies of 20-80 milliseconds on existing cellular networks in the next part of the article.