San Francisco, CA. The exponential increase of mobile data traffic will require disruptive approaches in the definition of the future 5G heterogeneous network, or hetnet, according to Cédric Dehos of CEA-LETI. He cited estimates of a 47% CAGR in mobile data-traffic growth rates driven by smartphones and tablets, with 60% of traffic carrying video. Further, he expects huge growth in M2M and IoT traffic by 2020.
Meeting the data-traffic challenge, he said during a SEMICON West presentation, will require improved spectral efficiency through the 5G New Radio architecture. In addition, Wi-Fi and femtocells will play a role in data-traffic offloading. He described LTE-M, NB-IoT, and 5G New Radio with massive MIMO as “more cellular,” while Wi-Fi, Sigfox, 802.11p, and Lora constitute “more than cellular.”
He described a < 6-GHz front-end module integrating PA, LNA, switch, and diplexer in RF SOI 130-nm LDMOS technology. The switch offers low RonCoff and high linearity; high-quality tunable capacitors support band/mode reconfiguration and tuning, offering support for more than 10 cellular bands and multimode compatibility with 2G/3G/4G.
Dehos also described an ultra-narrow-band transceiver for the low-power wide-area Sigfox network. It offers 100-Hz bandwidths on 850- to 920-MHz carrier frequencies with 0.1- to 20-kb/s DBPSK/GFSK downlink performance. It offers 15-mW receive power and in autonomous mode without an MPU can operate five to ten years on a coin cell.
A contactless connector operating at 60 GHz was another innovation that Dehos described. It incorporates an OOK transceiver realized in 65-nm SOI CMOS with integrated antennas. Leti has demonstrated HD video streaming with data rates to 2.5 Gb/s over a range of 10 cm with a power consumption of 50 mW.
He then elaborated on the heterogeneous network as part of the European H2020 project. The hetnet, he said, will make use of the huge available bandwidth at millimeter-wave frequencies, benefit from high frequency reuse, offer natural immunity to interference, and exhibit low EMF. He foresees the coexistence of three layers: 3G/4G networks, mmWave small cells, and 60-GHz/E-band backhauling.
He described a multiuser 60-GHz access point with sectorization in the azimuth plane and a 50- to 100-m range. A phased-array module will handle beam switching/beamforming. He also commented on a 60-GHz user terminal realized using high-performance low-cost CMOS and built in small-form-factor packaging with minimum routing length, high radiation performance, and good thermal dissipation.
Dehos said that a clear 5G roadmap does not exist, and global indecision and disagreement could lead to the emergence of new players. Nevertheless, he expects millimeter-wave frequencies to play a key role in device-to-device short-range communications and small-cell backhauling. The next hot topic, he said, will be the mmWave outdoor access point.
He is looking for progress in SOI/CMOS/BICMOS technologies, antennas, and packaging to reduce the cost of millimeter-wave devices. “Innovative approaches are still needed to solve the major technical challenges,” he concluded.
