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The recently introduced 5G New Radio is the first wireless standard natively designed to support critical and massive machine type communications (MTC). However, it is already becoming evident that some of the more demanding requirements for MTC cannot be fully supported by 5G networks. Alongside, emerging use cases and applications towards 2030 will give rise to new and more stringent requirements on wireless connectivity in general and MTC in particular. Next generation wireless networks, namely 6G, should therefore be an agile and efficient convergent network designed to meet the diverse and challenging requirements anticipated by 2030. This paper explores the main drivers and requirements of MTC towards 6G, and discusses a wide variety of enabling technologies. More specifically, we first explore the emerging key performance indicators for MTC in 6G. Thereafter, we present a vision for an MTC-optimized holistic end-to-end network architecture. Finally, key enablers towards (1) ultra-low power MTC, (2) massively scalable global connectivity, (3) critical and dependable MTC, and (4) security and privacy preserving schemes for MTC are detailed. Our main objective is to present a set of research directions considering different aspects for an MTC-optimized 6G network in the 2030-era.

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To face the exponential data traffic growth, the sub-THz spectrum (100-300 GHz) is envisioned for wireless communications. However, sub-THz systems are critically impacted by the strong phase noise of high frequency oscillators. This paper discusses the appropriate choice of phase noise model for sub-THz communications. Two phase noise models are introduced and compared: one correlated, accurate but complex, and another uncorrelated, analytically simpler. The expression of the likelihood ratio enables us to propose an analytical condition to select the best of the two models for a measured oscillator spectral characteristic. Numerical simulations are performed with realistic phase noise generated according to a state-of-the-art sub-THz oscillator and show that an uncorrelated Gaussian process is appropriate to model the impact of phase noise in sub-THz systems. Eventually, the proposed results are applied to link adaptation in the presence of phase noise in order to choose the most robust scheme between a coherent and a differential modulation.

International audienceThe Internet of Things aims to connect several billions of devices. Terminals are expected to be low cost, low power, and able to achieve successful communication at long range. While current Machine-to-Machine technologies tend to use spreading factors to meet the required specifications, we propose a more sophisticated use of redundant waveforms in a scheme called Turbo-FSK. This scheme involves Frequency-Shift-Keying (FSK) modulation at the transmission, and a turbo-decoder dedicated to the FSK waveforms at the receiver. Highly robust communication is achieved with a mere transmitter, as complexity is deported on the receiver side. Results are compared to common modulations using spreading factors, a significant gain in performance is achieved even with small packet sizes

Layered decoding is known to provide efficient and high-throughput implementation of LDPC decoders. However, the implementation of the layered architecture is not always straightforward because of the memory access conflicts in the a-posteriori information memory. In this paper, we focus our attention on a particular type of conflict introduced by the existence of multiple diagonal matrices in the DVB-T2 parity check matrix structure. We illustrate how the reordering of the matrix reduces the number of conflicts, at the cost of limiting the level of parallelism. We then propose a parity extending process to solve the remaining conflicts. Fixed point simulation results show coherent performance without modifying the layered architecture.

Abstract-The radio spectrum above 90GHz offers opportunities for huge signal bandwidths, and thus unprecedented increase in the wireless network capacity, beyond the performance defined for the 5G technology. This spectrum is essentially exploited for scientific services, but attracts nowadays many interest within the wireless telecommunications research community, following the same trend as in previous network generations. The BRAVE project that was launched at early 2018, aims at the elaboration of new waveforms able to efficiently operate in the 90-200 GHz spectrum. The researches rely on three complementary works: the definition of relevant communications scenarios (spectrum usage, application, environment, etc); the development of realistic models for the physical layer (propagation channel and RF equipments); and the elaboration of a single-carrier modulation compliant with the propagation channel properties, and allowing improvement on the spectral and energy efficiency. The motivation for this work, and the preliminary results on the waveform definition, are exposed in the present paper.Index Terms-Tbit/s, beyond-5G, above-90GHz, single-carrier.I. INTRODUCTION The activities of research and industrialization concerning the fifth generation (5G) of wireless communication systems are well-under way. Several solutions are proposed for standardization starting with 5G-NR (New Radio) [1]. There are three main objectives driving the development of 5G: the support to extreme wireless broadband services for applications such as the virtual and augmented realities, the 3D 4K video, cloud services, etc.; the connectivity for massive Internet of Thing (IoT) applications as: smart cities and factories, wireless health care; and the support of mission-critical services such as for autonomous vehicle, or security, with strong requirements on latency, guaranteed throughput, etc.All these target applications have highly different needs, but make 5G required to offer: throughputs in the order of Gbps with sub-millisecond latency along with 1000x capacity increase, and 100x connected devices per cell compared to nowadays existing mobile networks. Dense small-cell deployments, centralized RAN (Radio Access Network), advanced MIMO schemes and new millimeter-Wave (mmW) bands are key enablers to achieve the expected increase in spectral efficiency and capacity [2]. Frequency bands 26 or 28 GHz and 39 or 42 GHz will be likely selected for early 5G deployments.Alongside these 5G initiatives, the scientific community has also launched many investigations on the beyond 5G

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