D4.1 Draft air interface harmonization and user plane design

The METIS-II project envisions the design of a new air interface in order to fulfil all the performance requirements of the envisioned 5G use cases including some extreme low latency use cases and ultra-reliable transmission, xMBB requiring additional capacity that is only available in very high frequencies, as well as mMTC with extremely densely distributed sensors and very long battery life requirements. Designing an adaptable and flexible 5G Air Interface (AI), which will tackle these use cases while offering native multi-service support, is one of the key tasks of METIS-II WP4. This deliverable will highlight the challenges of designing an AI required to operate in a wide range of spectrum bands and cell sizes, capable of addressing the diverse services with often diverging requirements, and propose a design and suitability assessment framework for 5G AI candidates.Aydin, O.; Gebert, J.; Belschner, J.; Bazzi, J.; Weitkemper, P.; Kilinc, C.; Leonardo Da Silva, I.... (2016). D4.1 Draft air interface harmonization and user plane design. https://doi.org/10.13140/RG.2.2.24542.0288

D2.2 Draft Overall 5G RAN Design

This deliverable provides the consolidated preliminary view of the METIS-II partners on the 5 th generation (5G) radio access network (RAN) design at a mid-point of the project. The overall 5G RAN is envisaged to operate over a wide range of spectrum bands comprising of heterogeneous spectrum usage scenarios. More precisely, the 5G air interface (AI) is expected to be composed of multiple so-called AI variants (AIVs), which include evolved legacy technology such as Long Term Evolution Advanced (LTE-A) as well as novel AIVs, which may be tailored to particular services or frequency bands.Arnold, P.; Bayer, N.; Belschner, J.; Rosowski, T.; Zimmermann, G.; Ericson, M.; Da Silva, IL.... (2016). D2.2 Draft Overall 5G RAN Design. https://doi.org/10.13140/RG.2.2.17831.1424

Design and Linearization of Energy Efficiency Power Amplifier in Nonlinear OFDM Transmitter for LTE-5G Applications. Simulation and measurements of energy efficiency power amplifier in the presence of nonlinear OFDM transmitter system and digital predistortion based on Hammerstein-Wiener method

This research work has made an effort to understand a novel line of radio frequency power amplifiers (RFPAs) that address initiatives for efficiency enhancement and linearity compensation to harmonize the fifth generation (5G) campaign. The objective is to enhance the performance of an orthogonal frequency division multiplexing-long term evolution (OFDM-LTE) transmitter by reducing the nonlinear distortion of the RFPA. The first part of this work explores the design and implementation of 15.5 W class AB RF power amplifier, adopting a balanced technique to stimulate efficiency enhancement and redeeming exhibition of excessive power in the transmitter. Consequently, this work goes beyond improving efficiency over a linear RF power amplifier design; in which a comprehensive investigation on the fundamental and harmonic components of class F RF power amplifier using a load-pull approach to realise an optimum load impedance and the matching network is presented. The frequency bandwidth for both amplifiers was allocated to operate in the 2.620-2.690 GHz of mobile LTE applications. The second part explores the development of the behavioural model for the class AB power amplifier. A particular novel, Hammerstein-Wiener based model is proposed to describe the dynamic nonlinear behaviour of the power amplifier. The RF power amplifier nonlinear distortion is approximated using a new linear parameter approximation approach. The first and second-order Hammerstein-Wiener using the Normalised Least Mean Square Error (NLMSE) algorithm is used with the aim of easing the complexity of filtering process during linear memory cancellation. Moreover, an enhanced adaptive Wiener model is proposed to explore the nonlinear memory effect in the system. The proposed approach is able to balance between convergence speed and high-level accuracy when compared with behavioural modelling algorithms that are more complex in computation. Finally, the adaptive predistorter technique is implemented and verified in the OFDM transceiver test-bed. The results were compared against the computed one from MATLAB simulation for OFDM and 5G modulation transmitters. The results have confirmed the reliability of the model and the effectiveness of the proposed predistorter.Fundacão para a Ciência e a Tecnologia, Portugal, under European Union’s Horizon 2020 research and innovation programme ... grant agreement H2020-MSCA-ITN- 2016 SECRET-722424 I also acknowledge the role of the National Space Research and Development Agency (NASRDA) Sokoto State Government Petroleum Technology Trust Fund (PTDF

30 GHz Path Loss Modeling and Performance Evaluation for Noncoherent M-ary Frequency Shift Keying in the 30 GHz Band

A candidate millimeter-wave (mmWave) frequency band and modulation scheme that could fit to many present and future applications has been presented in this work. As is being explored by industry, we also suggest the 30 GHz band as a candidate carrier frequency and non-coherent frequency shift keying (NC-FSK) as a potential modulation scheme for future communication applications. The primary applications are aimed at 5th generation (5G) cellular type systems. Propagation measurements were conducted for outdoor and indoor environments using directional horn antennas for both co-polarized and cross-polarized antenna configurations to model the path loss for our candidate band. The measurements were conducted in typical line-of-sight (LOS) and non-LOS (NLOS) environments in a large building on the University of South Carolina campus, specifically at Swearingen Engineering Center. Several propagation path loss (PL) models are presented based upon this collected data. We can use these PL models in link budgets for estimating transmit power, antenna gains, receiver characteristics (e.g., noise figure), and link distances. The measurements also contribute to the body of knowledge on wireless channel propagation path loss for bands near 30 GHz. Another measurement campaign was also conducted at the USC campus to measure a unique and complicated vegetation attenuation that may be considered a large challenge to mmWave systems. Radio wave attenuation and depolarization effects through several broadleaf evergreen shrubs at 31 GHz are reported, based upon measurements. To obtain a comparative reference for this mmWave attenuation, another measurement was also conducted at 5 GHz. From these measurements, we analyzed the proportional relationships between the attenuation and the shrub density (related to species), depth, and measurement geometry. Three different shrub species with different densities and depths, and for different measurement geometries, were employed. Results are in terms of measured specific attenuations at 31 GHz—the attenuation in dB/m. These will also be useful for link budget design, and outdoor and outdoor-indoor models for future mmWave communication. For our 5G modulation scheme candidate, we evaluate its performance at 31 GHz via an empirical 3-D mmWave channel simulator: the NYUSIM channel model. As with all digital communication systems, performance is measured in terms of error ratios, and we evaluate the bit error rate (BER) performance of NC-FSK for different symbol rates over a variety of wireless mmWave channels. The NC-FSK scheme is known to be energy efficient for large alphabet size, and this is one of its virtues. Another is that since it is a form of FM, nonlinear amplification (far less costly than linear amplification) can be used. The performance evaluations enable us to present enhancements and trade-offs that can be done to improve the system performance by adjustment of the design parameters, i.e., modulation alphabet size and symbol rate, which together determine bandwidth (BW)

Adaptive OFDM Index Modulation for Two-Hop Relay-Assisted Networks

In this paper, we propose an adaptive orthogonal frequency-division multiplexing (OFDM) index modulation (IM) scheme for two-hop relay networks. In contrast to the traditional OFDM IM scheme with a deterministic and fixed mapping scheme, in this proposed adaptive OFDM IM scheme, the mapping schemes between a bit stream and indices of active subcarriers for the first and second hops are adaptively selected by a certain criterion. As a result, the active subcarriers for the same bit stream in the first and second hops can be varied in order to combat slow frequency-selective fading. In this way, the system reliability can be enhanced. Additionally, considering the fact that a relay device is normally a simple node, which may not always be able to perform mapping scheme selection due to limited processing capability, we also propose an alternative adaptive methodology in which the mapping scheme selection is only performed at the source and the relay will simply utilize the selected mapping scheme without changing it. The analyses of average outage probability, network capacity and symbol error rate (SER) are given in closed form for decode-and-forward (DF) relaying networks and are substantiated by numerical results generated by Monte Carlo simulations.Comment: 30 page

Performance Analysis, Resource Allocation and Optimization of Cooperative Communication Systems under Generalized Fading Channels

The increasing demands for high-speed data transmission, efficient wireless access, high quality of service (QoS) and reliable network coverage with reduced power consumption impose demanding intensive research efforts on the design of novel wireless communication system architectures. A notable development in the area of communication theory is the introduction of cooperative communication systems. These technologies become promising solution for the next-generation wireless transmission systems due to their applicability in size, power, hardware and price constrained devices, such as cellular mobile devices, wireless sensors, ad-hoc networks and military communications, being able to provide, e.g., diversity gain against fading channels without the need for installing multiple antennas in a single terminal. The performance of the cooperative systems can in general be significantly increased by allocating the limited power efficiently. In this thesis, we address in detail the performance analysis, resource allocation and optimization of such cooperative communication systems under generalized fading channels. We focus first on energy-efficiency (EE) optimization and optimal power allocation (OPA) of regenerative cooperative network with spatial correlation effects under given power constraint and QoS requirement. The thesis also investigates the end-to-end performance and power allocation of a regenerative multi-relay cooperative network over non-homogeneous scattering environment, which is realistic case in practical wireless communication scenarios. Furthermore, the study investigates the end-to-end performance, OPA and energy optimization analysis under total power constraint and performance requirement of full-duplex (FD) relaying transmission scheme over asymmetric generalized fading models with relay self-interference (SI) effects.The study first focuses on exact error analysis and EE optimization of regenerative relay systems under spatial correlation effects. It first derives novel exact and asymptotic expressions for the symbol-error-rates (SERs) of M -ary quadrature amplitude and M -ary phase-shift keying (M -QAM) and (M -PSK) modulations, respectively, assuming a dual-hop decode-and-forward relay system, spatial correlation, path-loss effects and maximum-ratio-combing (MRC) at the destination. Based on this, EEoptimization and OPA are carried out under certain QoS requirement and transmit power constraints.Furthermore, the second part of the study investigates the end-to-end performance and power allocation of MRC based regenerative multi-relay cooperative system over non-homogeneous scattering environment. Novel exact and asymptotic expressions are derived for the end-to-end average SER for M -QAM and M -PSK modulations.The offered results are employed in performance investigations and power allocation formulations under total transmit power constraints.Finally, the thesis investigates outage performance, OPA and energy optimization analysis under certain system constraints for the FD and half-duplex (HD) relaying systems. Unlike the previous studies that considered the scenario of information transmission over symmetric fading conditions, in this study we considered the scenario of information transmission over the most generalized asymmetric fading environments.The obtained results indicate that depending on the severity of multipath fading, the spatial correlation between the direct and relayed paths and the relay location, the direct transmission is more energy-efficient only for rather short transmission distances and until a certain threshold. Beyond this, the system benefits substantially from the cooperative transmission approach where the cooperation gain increases as the transmission distance increases. Furthermore, the investigations on the power allocation for the multi-relay system over the generalized small-scale fading model show that substantial performance gain can be achieved by the proposed power allocation scheme over the conventional equal power allocation (EPA) scheme when the source-relay and relay-destination paths are highly unbalanced. Extensive studies on the FD relay system also show that OPA provides significant performance gain over the EPA scheme when the relay SI level is relatively strong. In addition, it is shown that the FD relaying scheme is more energy-efficient than the reference HD relaying scheme at long transmission distances and for moderate relay SI levels.In general, the investigations in this thesis provide tools, results and useful insights for implementing space-efficient, low-cost and energy-efficient cooperative networks, specifically, towards the future green communication era where the optimization of the scarce resources is critical