Evangelos Mellios

5G 3GPP-Like Channel Models for Outdoor Urban Microcellular and Macrocellular Environments

For the development of new 5G systems to operate in bands up to 100 GHz, there is a need for accurate radio propagation models at these bands that currently are not addressed by existing channel models developed for bands below 6 GHz. This document presents a preliminary overview of 5G channel models for bands up to 100 GHz. These have been derived based on extensive measurement and ray tracing results across a multitude of frequencies from 6 GHz to 100 GHz, and this document describes an initial 3D channel model which includes: 1) typical deployment scenarios for urban microcells (UMi) and urban macrocells (UMa), and 2) a baseline model for incorporating path loss, shadow fading, line of sight probability, penetration and blockage models for the typical scenarios. Various processing methodologies such as clustering and antenna decoupling algorithms are also presented.

A multi-modal sensor infrastructure for healthcare in a residential environment

Ambient Assisted Living (AAL) systems based on sensor technologies are seen as key enablers to an ageing society. However, most approaches in this space do not provide a truly generic ambient space - one that is not only capable of assisting people with diverse medical conditions, but can also recognise the habits of healthy habitants, as well as those with developing medical conditions. The recognition of Activities of Daily Living (ADL) is key to the understanding and provisioning of appropriate and efficient care. However, ADL recognition is particularly difficult to achieve in multi-resident spaces; especially with single-mode (albeit carefully crafted) solutions, which only have limited capabilities. To address these limitations we propose a multi-modal system architecture for AAL remote healthcare monitoring in the home, gathering information from multiple, diverse (sensor) data sources. In this paper we report on developments made to-date in various technical areas with respect to critical issues such as cost, power consumption, scalability, interoperability and privacy.

Transport layer performance in 5G mmWave cellular

The millimeter wave (mmWave) bands are likely to play a significant role in next generation cellular systems due to the possibility of very high throughput thanks to the availability of massive bandwidth and high-dimensional antennas. Especially in Non-Line-of-Sight conditions, significant variations in the received RF power can occur as a result of the scattering from nearby building and terrain surfaces. Scattering objects come and go as the user moves through the local environment. At the higher end of the mmWave band, rough surface scatter generates cluster-based small-scale fading, where signal levels can vary by more than 20 dB over just a few wavelengths. This high level of channel variability may present significant challenges for congestion control. Using our recently developed end-to-end mmWave ns3-based framework, this paper presents the first performance evaluation of TCP congestion control in next-generation mmWave networks. Importantly, the framework can incorporate detailed models of the mmWave channel, beamforming and tracking algorithms, and builds on statistical channel models derived from real measurements in New York City, as well as detailed ray traces.

Indoor 5G 3GPP-like channel models for office and shopping mall environments

Future mobile communications systems are likely to be very different to those of today with new service innovations driven by increasing data traffic demand, increasing processing power of smart devices and new innovative applications. To meet these service demands the telecommunications industry is converging on a common set of 5G requirements which includes network speeds as high as 10 Gbps, cell edge rate greater than 100 Mbps, and latency of less than 1 msec. To reach these 5G requirements the industry is looking at new spectrum bands in the range up to 100 GHz where there is spectrum availability for wide bandwidth channels. For the development of new 5G systems to operate in bands up to 100 GHz there is a need for accurate radio propagation models which are not addressed by existing channel models developed for bands below 6 GHz. This paper presents a preliminary overview of the 5G channel models for bands up to 100 GHz in indoor offices and shopping malls, derived from extensive measurements across a multitude of bands. These studies have found some extensibility of the existing 3GPP models (e.g. 3GPP TR36.873) to the higher frequency bands up to 100 GHz. The measurements indicate that the smaller wavelengths introduce an increased sensitivity of the propagation models to the scale of the environment and show some frequency dependence of the path loss as well as increased occurrence of blockage. Further, the penetration loss is highly dependent on the material and tends to increase with frequency. The small-scale characteristics of the channel such as delay spread and angular spread and the multipath richness is somewhat similar over the frequency range, which is encouraging for extending the existing 3GPP models to the wider frequency range. Further work will be carried out to complete these models, but this paper presents the first steps for an initial basis for the model development.

Overview of Millimeter Wave Communications for Fifth-Generation (5G) Wireless Networks—With a Focus on Propagation Models

This paper provides an overview of the features of fifth generation (5G) wireless communication systems now being developed for use in the millimeter wave (mmWave) frequency bands. Early results and key concepts of 5G networks are presented, and the channel modeling efforts of many international groups for both licensed and unlicensed applications are described here. Propagation parameters and channel models for understanding mmWave propagation, such as line-of-sight (LOS) probabilities, large-scale path loss, and building penetration loss, as modeled by various standardization bodies, are compared over the 0.5–100 GHz range.

Impact of antenna pattern and handset rotation on macro-cell and pico-cell propagation in heterogeneous LTE networks

This paper studies the impact of antenna pattern and user handset random orientation on macro-cell and pico-cell propagation in heterogeneous LTE networks. The analysis combines measured 3D radiation patterns of basestations and handset antennas with state-of-the-art 3D ray-tracing for a large number of macro-cell and pico-cell basestations and user locations/orientations in an urban environment. Macro and pico propagation characteristics are presented as cumulative distribution functions of the received signal strength, the K-factor, the RMS delay spread and the RMS angle-of-departure and angle-of-arrival azimuth and elevation spreads. It is shown that using measured antenna patterns and considering the random user handset orientation has significant impact on the propagation characteristics of a heterogeneous LTE network.

Investigation into off-body links for wrist mounted antennas in bluetooth systems

This paper presents a detailed investigation into off-body links for wrist mounted Bluetooth Low Energy (BLE) devices for an indoor environment and revolves around three low profile antennas (microstrip patch, printed monopole and external monopole). It studies the received signal strength across different usage scenarios and obstructions such as body shadow, wall and ceiling through measurement campaigns carried out in a 2-storey house. It is observed that RSSIs show little variation from the mean value at any position in a given room of the house. In the living room, the average RSSI for patch, printed and external monopole is close to -61,-73 and -61 dBm respectively. The study describes the effect of usual obstructions such as wall and ceiling to off-body links and shows that the range of RSSI for any antenna (30 dBm at P=0.5 for Patch Antenna) is bounded at one end by the CDF of wall plus body shadow and at the other end by CDF of Line of Sight (LOS). The effect of body shadowing is studied in greater detail. It is observed that the microstrip patch antenna in LOS, under a ceiling and behind a wall, drops by approximately 15dB, 5dB and 10dB at P=0.4 when it goes into body shadow. The study also suggests that the Access Point (AP) on the ceiling provides better off-body links as compared to it in the adjacent room. The study compares the overall performance of the three antennas across all possible usage scenarios, obstructions & polarizations and concludes that the external monopole and patch antenna performs better than printed monopole by approximately 10-13 dBm. Finally, the study shows the variation of Packet Error Rate (PER) with RSSI and determines threshold values of RSSI for acceptable PERs, for reliable and robust applications.

SPW-1: A Low-Maintenance Wearable Activity Tracker for Residential Monitoring and Healthcare Applications

In this paper, we present SPW-1; a low-profile versatile wearable activity tracker that employs two ultra-low-power accelerometers and relies on Bluetooth Low Energy (BLE) for wireless communication. Aiming for a low maintenance system, SPW-1 is able to offer a battery lifetime of multiple months. Measurements on its wireless performance in a real residential environment with thick brick walls, demonstrate that SPW-1 can fully cover a room and - in most cases - the adjacent room, as well. SPW-1 is a research platform that is aimed to be used both as a data collecting tool for health-oriented studies outside the laboratory, but also for research on wearable technologies and body-centric communications. As a result, SPW-1 incorporates versatile features, such as external sensor support, various powering options, and accelerometer configuration options that can support a wide range applications from kinematics to long-term activity recognition.

Ray-tracing urban macrocell propagation statistics and comparison with WINNER II/+ measurements and models

This paper combines measured 3D basestation (BS) and user handheld antenna radiation patterns with a state-of-the-art 3D ray-tracing tool in order to derive a set of urban macrocell propagation statistics suitable for Long Term Evolution (LTE) cellular network planning. Results are presented as cumulative distribution functions (CDFs) and as a function of distance from the BS. Best-fit normal and lognormal distribution parameters are also presented. Ray-tracing is compared with measurements and models from the WINNER II and WINNER+ standards, demonstrating the limitations of the empirical “one size fits all” standardised models. We conclude that site-specific models, which are able to factor in the impact of specific BS and user handheld antenna patterns and geometries or different propagation environments and terrains, offer significant advantages when designing an efficient LTE cellular network.

Throughput sensitivity to antenna pattern and orientation in 802.11n networks

In this paper the throughput and packet error rate for an in-home 802.11n network is theoretically derived for two different types of 3x3 antenna configurations. Our first configuration assumes the use of three low directivity omni-dectional elements. The second arrangement makes use of three orthogonally orientated directional elements. The spatial and temporal characteristics of the in-home channels are modelled using 3D ray tracing and combined with appropriately orientated complex polarmetric patterns for each antenna element. Physical layer throughput is computed for all modulation and coding schemes using a received bit information rate abstraction technique. The theory shows that directional antennas outperform the omni-directional devices in most cases. Directional elements show increased sensitivity to orientation, however for 83% of locations and orientations they still result in throughput enhancement. Directional antennas provide a 33% improvement in average data rate for random client orientations, improving to 52% with optimum alignment to the multipath.