Hugo Tullberg

Scenarios for 5G mobile and wireless communications: the vision of the METIS project

METIS is the EU flagship 5G project with the objective of laying the foundation for 5G systems and building consensus prior to standardization. The METIS overall approach toward 5G builds on the evolution of existing technologies complemented by new radio concepts that are designed to meet the new and challenging requirements of use cases todays radio access networks cannot support. The integration of these new radio concepts, such as massive MIMO, ultra dense networks, moving networks, and device-to-device, ultra reliable, and massive machine communications, will allow 5G to support the expected increase in mobile data volume while broadening the range of application domains that mobile communications can support beyond 2020. In this article, we describe the scenarios identified for the purpose of driving the 5G research direction. Furthermore, we give initial directions for the technology components (e.g., link level components, multinode/multiantenna, multi-RAT, and multi-layer networks and spectrum handling) that will allow the fulfillment of the requirements of the identified 5G scenarios.

The Foundation of the Mobile and Wireless Communications System for 2020 and Beyond: Challenges, Enablers and Technology Solutions

In 2020, mobile and wireless traffic volume is expected to increase thousand-fold over 2010 figures. Moreover, an increase in the number of wirelessly-connected devices to counts in the tens of billions will have a profound impact on society. Massive machine communication, forming the basis for the Internet of Things, will make our everyday life more efficient, comfortable and safer, through a wide range of applications including traffic safety and medical services. The variety of applications and data traffic types will be significantly larger than today, and will result in more diverse requirements on services, devices and networks. METIS is set up by leading global players to prepare the migration towards tomorrows multi-purpose global communication infrastructure, serving humans and things. The main objective of METIS is to lay the foundation for this future global mobile and wireless communications system, and to generate a global consensus here. In particular, METIS will provide new solutions which fit the needs beyond 2020.

Waveform and Numerology to Support 5G Services and Requirements

The standardization of the next generation 5G radio access technology has just started in 3GPP with the ambition of making it commercially available by 2020. There are a number of features that are unique for 5G radio access compared to the previous generations such as a wide range of carrier frequencies and deployment options, diverse use cases with very different user requirements, small-size base stations, self-backhaul, massive MIMO, and large channel bandwidths. In this article, we propose a flexible physical layer for the NR to meet the 5G requirements. A symmetric physical layer design with OFDM is proposed for all link types, including uplink, downlink, device-to-device, and backhaul. A scalable OFDM waveform is proposed to handle the wide range of carrier frequencies and deployments.

Serial concatenated TCM with an inner accumulate code-part I: maximum-likelihood analysis

We propose a serial concatenated trellis-coded modulation system using one or more inner rate-1 accumulate codes and a mapping to a higher order, Gray-labeled signal constellation. As outer codes, we consider repeat codes, single parity-check codes, and convolutional codes. We show that under maximum-likelihood decoding, there exists a signal-to-noise ratio threshold beyond which the bit-error probability goes to zero as the blocklength goes to infinity. We then evaluate the performance for finite blocklengths using a modified union bound. Computer simulations demonstrate that the proposed system, despite its use of a simple rate-1 inner code, achieves performance in additive white Gaussian noise and Rayleigh fading that is comparable to, or better than, that of more complex systems suggested in the literature.

Serial concatenated TCM with an inner accumulate code - part II: density-evolution analysis

In a companion paper, we showed the existence of decoding thresholds for maximum-likelihood (ML) decoding of a serial concatenated trellis-coded modulation (SCTCM) system with one or more inner accumulate codes. In this paper, we compute the decoding thresholds for an iterative, non-ML decoder by density evolution (DE), assuming infinite blocklengths. We also derive a stability condition for the particular case of an outer parity-check code and a single inner accumulate code. We show that, for equiprobable signaling, the bit-wise log-likelihood ratio densities for higher order constellations are symmetric. Furthermore, when used in DE, these densities can be averaged without significantly affecting the resulting threshold values. For an outer single parity-check code, the lowest decoding thresholds are achieved with two inner accumulate codes. For an outer repeat code, a single inner accumulate code gives the lowest thresholds. At code rates r/sub c/>2/3, the decoding thresholds for the SCTCM system are within 1 dB of the constellation-constrained channel capacity for additive white Gaussian noise channels, and within 1.5 dB for independent, identically distributed Rayleigh channels. Simulation results verify the computed thresholds.

Serial concatenated trellis coded modulation with inner rate-1 accumulate code

We propose a serial concatenated trellis coded modulation system using one or more inner accumulate code(s) and a Gray-labeled signal constellation. We show the existence of a threshold, such that if the signal-to-noise ratio (SNR) exceeds this threshold, the bit error probability goes to zero as the blocklength goes to infinity. Tight numerical values for the thresholds for an iterative decoder are found by density evolution. Despite the simple inner code, the simulated performance in AWGN and Rayleigh fading is comparable to that of more complex systems suggested in the literature.

The METIS 5G Architecture: A Summary of METIS Work on 5G Architectures

During the last two years, the METIS project (Mobile and wireless communications Enablers for the Twenty-twenty Information Society) has been conducting research on 5G-enabling technology components. This paper provides a summary of METIS work on 5G architectures. The architecture description is presented from different viewpoints. First, a functional architecture is presented that may lay a foundation for development of first novel 5G network functions. It is based on functional decomposition of most relevant 5G technology components provided by METIS. The logical orchestration & control architecture depicts the realization of flexibility, scalability and service orientation needed to fulfil diverse 5G requirements. Finally, a third viewpoint reveals deployment aspects and function placement options for 5G.

Bit-interleaved coded modulation for delay-constrained mobile communication channels

The role of the interleaver in a bit-interleaved coded modulation (BICM) system is investigated. Square block interleavers and convolutional interleavers are compared to the random interleaver originally used by Zehavi (1992). It is shown that for short latencies (20 ms) the square block interleaver performs better than the random interleaver. However, when the side of the square block interleaver, /spl radic/N is a multiple of n, the coded bits are grouped in such a way that the diversity, and hence performance is reduced. For short delays, the convolutional interleaver outperforms both the random and square block interleaver as the vehicle speed varies from pedestrian to freeway speeds.

5G use cases and system concept

In the 5G vision, access to information and sharing of data are possible anywhere and anytime to anyone and anything. 5G expands the usage of human-centric communications to include both human-centric and machine-centric communications. Mobile and wireless communication will increasingly become the primary way for humans and machines to access information and services. This will lead to socio-economic changes not yet imaginable, including improvements in productivity, sustainability, entertainment and well-being. To make this vision a reality, the capabilities of 5G systems must extend far beyond those of previous generations. 5G systems must exhibit greater flexibility than previous generations, and involve farther-reaching integration including not only the traditional radio access networks, but also core network, transport and application layers. Altogether, this requires a new way of thinking in 5G wireless access, network architecture and applications. In this chapter, first, the needs of the end users are described in terms of use cases and requirements, and then an overview of the 5G system concept meeting these user needs is given. Use cases and requirements This section provides the vision based on the expected societal development toward the year 2020 and beyond from the end-user perspective described in Chapter 1. Concrete use cases that have specific goals and challenges are provided. To achieve the goals and to overcome the challenges, there are certain specific requirements for 5G systems to meet. A collection of diverse use cases gives a set of challenging requirements that have to be fulfilled by 5G systems. The material below is largely based on [1]–[8]. The technical solutions to address these requirements are then discussed in the later chapters of this book. Use cases In this section, the most relevant 5G use cases are presented. Further, the challenges and requirements for each of these are named. As mentioned in Chapter 1, 5G will become a cornerstone in many of the economic sectors. Table 2.1 shows as an example how the addressed use cases map onto the major economic sectors. It should be noted that the list of use cases is far from being exhaustive. Only the most relevant ones from technical and business perspective are given. Finally, some of the use cases can be considered as a set of use cases (e.g. smart city or public safety).