A device coexistence enabler for future 5G networks
To fulfill their promise of providing a 1 000-time increase in data rates, future 5G networks need to use a wide range of spectral bands. But as this range keeps expanding, competition between systems using the network also becomes fiercer: coexistence becomes a problem. “It’s a necessity of the 5G evolution. To further improve spatial spectral utilisation, 5G systems are expected to more densely deploy the wireless infrastructure and pave the way for the utilisation of the 27GHz and higher frequency bands. It will inevitably increase interference between users and between systems, so we need to find new ways to enable their coexistence,” explains Dr Mirjana Videnovic-Misic, coordinator of the FUDACT project. Dr Videnovic-Misic is quite familiar with this issue. She notably spent the past three years designing a wideband blocker resilient picocell receiver in STMicroelectronics’ 28nm ultra-thin body and buried oxide Fully Depleted SOI (UTBB-FD-SOI) technology. “As most of the deep submicron technologies suffer from significant process variations, I have come up with an optimisation procedure able to exploit the unique features of the 28nm UTBB FD-SOI CMOS process while keeping a robust circuit/system design,” she says. FUDACT is a mixer-first receiver that boasts a natural resiliency to strong out-of-band (OOB) blockers, and also includes a biquad filter as a second base-band receiver stage. When designed carefully, it can suppress the OOB signal while weak wanted signals are sampled and multiplied with adequate weighting factors to obtain information about them in the baseband. The receiver also benefits from extended body biasing voltage range and a high body efficiency specific to the 28nm UTBB FDSOI CMOS technology. By applying this, “It is possible to compensate for process variations and secure noise, linearity and power requirements within +/- 10% of the targeted values for the base-band amplifier- the core of the designed receiver,” Dr Videnovic-Misic explains. The FUDACT design is still being worked on, with the next stage being laboratory validation (after which it will reach TRL4). Dr Videnovic-Misic hopes to move ahead with its development thanks to the new position she recently acquired at Silicon Austria Labs (SAL) – a newly formed research centre for electronic-based systems that aims to establish itself as one of European points of excellence. “As a senior scientist, I will be in charge of recruiting, training, team leading and designing integrated circuits. This will give me the chance to put in practice all the skills I obtained during FUDACT. It will enable me to directly contribute to and support the sustainable growth of RFIC competent engineers in Europe. There is a possibility that this project will be in some form continued there, as a cooperation between industry and SAL.” There is little doubt that coexistence will remain a hot topic among 5G stakeholders over the next few years. As Dr Videnovic-Misic points out, even the United States’ Federal Communications Commission has decided in favour of imposing new rules and regulations designed to speed up the deployment of small cells, so that the US can ‘win’ the global 5G race. Pursuing the FUDACT research could be key to enabling Europe to keep up.
Keywords
FUDACT, 5G, coexistence, UTBB FD-SOI, STMicroelectronics, mixer-first receiver
