Performance characterisation of MIMO-UWB systems for indoor environments

Although recent advances in wireless system technologies have provided ever increasing throughputs, end user demand continues to increase unabated. The research investigates the performance of a system harnessing two relatively new but powerful technologies, Multiple-Input and Multiple-Output (MIMO) and Ultra Wideband (UWB) transmission as a possible solution to meet the growing demand for capacity. Each of these technologies in its own right has been subject to a large volume of research and has been proven to bring an increase in throughput. Nevertheless the predicted future demand will outstrip what each strategy can provide individually. MIMO-UWB systems are thus an emerging wireless solution with, in particular, the potential to satisfy short distance, high speed transmission requirements within indoor environments. Before any system is deployed it is important to characterise performance within representative operating environments. The study therefore emulates appropriate indoor environments, defines an experimental protocol to execute a range of measurements that provide robust evidence of the behaviour of the combined system within indoor scenarios. The application scenario dictates that the transmitter represents a gateway device attached to the ceiling and the receiver, a user device set on a table. The sequence of measurements relate to different positioning of the user device, with different angles and ranges to the gateway device, the layout of antenna placements being important. The output of the study is an accurate model for engineers and, the foundation for the design of MIMO-UWB systems for indoor services.Although recent advances in wireless system technologies have provided ever increasing throughputs, end user demand continues to increase unabated. The research investigates the performance of a system harnessing two relatively new but powerful technologies, Multiple-Input and Multiple-Output (MIMO) and Ultra Wideband (UWB) transmission as a possible solution to meet the growing demand for capacity. Each of these technologies in its own right has been subject to a large volume of research and has been proven to bring an increase in throughput. Nevertheless the predicted future demand will outstrip what each strategy can provide individually. MIMO-UWB systems are thus an emerging wireless solution with, in particular, the potential to satisfy short distance, high speed transmission requirements within indoor environments. Before any system is deployed it is important to characterise performance within representative operating environments. The study therefore emulates appropriate indoor environments, defines an experimental protocol to execute a range of measurements that provide robust evidence of the behaviour of the combined system within indoor scenarios. The application scenario dictates that the transmitter represents a gateway device attached to the ceiling and the receiver, a user device set on a table. The sequence of measurements relate to different positioning of the user device, with different angles and ranges to the gateway device, the layout of antenna placements being important. The output of the study is an accurate model for engineers and, the foundation for the design of MIMO-UWB systems for indoor services

Improving the Performance of Wireless LANs

This book quantifies the key factors of WLAN performance and describes methods for improvement. It provides theoretical background and empirical results for the optimum planning and deployment of indoor WLAN systems, explaining the fundamentals while supplying guidelines for design, modeling, and performance evaluation. It discusses environmental effects on WLAN systems, protocol redesign for routing and MAC, and traffic distribution; examines emerging and future network technologies; and includes radio propagation and site measurements, simulations for various network design scenarios, numerous illustrations, practical examples, and learning aids

Survey on wireless technology trade-offs for the industrial internet of things

Aside from vast deployment cost reduction, Industrial Wireless Sensor and Actuator Networks (IWSAN) introduce a new level of industrial connectivity. Wireless connection of sensors and actuators in industrial environments not only enables wireless monitoring and actuation, it also enables coordination of production stages, connecting mobile robots and autonomous transport vehicles, as well as localization and tracking of assets. All these opportunities already inspired the development of many wireless technologies in an effort to fully enable Industry 4.0. However, different technologies significantly differ in performance and capabilities, none being capable of supporting all industrial use cases. When designing a network solution, one must be aware of the capabilities and the trade-offs that prospective technologies have. This paper evaluates the technologies potentially suitable for IWSAN solutions covering an entire industrial site with limited infrastructure cost and discusses their trade-offs in an effort to provide information for choosing the most suitable technology for the use case of interest. The comparative discussion presented in this paper aims to enable engineers to choose the most suitable wireless technology for their specific IWSAN deployment

Packet Loss in Terrestrial Wireless and Hybrid Networks

The presence of both a geostationary satellite link and a terrestrial local wireless link on the same path of a given network connection is becoming increasingly common, thanks to the popularity of the IEEE 802.11 protocol. The most common situation where a hybrid network comes into play is having a Wi-Fi link at the network edge and the satellite link somewhere in the network core. Example of scenarios where this can happen are ships or airplanes where Internet connection on board is provided through a Wi-Fi access point and a satellite link with a geostationary satellite; a small office located in remote or isolated area without cabled Internet access; a rescue team using a mobile ad hoc Wi-Fi network connected to the Internet or to a command centre through a mobile gateway using a satellite link. The serialisation of terrestrial and satellite wireless links is problematic from the point of view of a number of applications, be they based on video streaming, interactive audio or TCP. The reason is the combination of high latency, caused by the geostationary satellite link, and frequent, correlated packet losses caused by the local wireless terrestrial link. In fact, GEO satellites are placed in equatorial orbit at 36,000 km altitude, which takes the radio signal about 250 ms to travel up and down. Satellite systems exhibit low packet loss most of the time, with typical project constraints of 10−8 bit error rate 99% of the time, which translates into a packet error rate of 10−4, except for a few days a year. Wi-Fi links, on the other hand, have quite different characteristics. While the delay introduced by the MAC level is in the order of the milliseconds, and is consequently too small to affect most applications, its packet loss characteristics are generally far from negligible. In fact, multipath fading, interference and collisions affect most environments, causing correlated packet losses: this means that often more than one packet at a time is lost for a single fading even

Impact of the propagation model on the capacity in small‐cell networks: comparison between the UHF/SHF and the millimetre wavebands

This work shows how both frequency and the election of path loss model affect estimated spectral efficiency. Six different frequency bands are considered, ranging from 2.6 GHz in the Ultra High Frequency (UHF) band to 73 GHz in the millimetre wave bands (mmWaves), using both single-slope and two-slope path-loss models. We start by comparing four ur ban path loss models for UHF: the urban/vehicular and pedestrian test environment from the ITU-R M. 1255 Report, which includes the two-slope urban micro line-of-sight (LoS) and NLoS, from the ITU-R 2135 Report. Then, we consider mmWaves taking into con26 sideration the modified Friis propagation model, followed by an analysis of the through put for the 2.6, 3.5, 28, 38, 60 and 73 GHz frequency bands. We have found that the signal to-interference-plus-noise ratio, as estimated with the more realistic two-slope model, is lower for devices that are within the break-point of the transmitter, which is a small dis tance in the UHF/SHF band. As a result, spectral efficiency is higher with mmWaves than with UHF/SHF spectrum when cell radius is under 40 meters but not when cells are larger. Consequently, mmWaves spectrum will be more valuable as cells get small. We also find that capacity as estimated with the two-slope model is considerably smaller than one would obtain with the one-slope model when cells are small but there is little difference in the models when cells are larger. Thus, as cells get smaller, the use of one slope models may underestimate the number of cells that must be deployed.info:eu-repo/semantics/acceptedVersio

Survey of Spectrum Sharing for Inter-Technology Coexistence

Increasing capacity demands in emerging wireless technologies are expected to be met by network densification and spectrum bands open to multiple technologies. These will, in turn, increase the level of interference and also result in more complex inter-technology interactions, which will need to be managed through spectrum sharing mechanisms. Consequently, novel spectrum sharing mechanisms should be designed to allow spectrum access for multiple technologies, while efficiently utilizing the spectrum resources overall. Importantly, it is not trivial to design such efficient mechanisms, not only due to technical aspects, but also due to regulatory and business model constraints. In this survey we address spectrum sharing mechanisms for wireless inter-technology coexistence by means of a technology circle that incorporates in a unified, system-level view the technical and non-technical aspects. We thus systematically explore the spectrum sharing design space consisting of parameters at different layers. Using this framework, we present a literature review on inter-technology coexistence with a focus on wireless technologies with equal spectrum access rights, i.e. (i) primary/primary, (ii) secondary/secondary, and (iii) technologies operating in a spectrum commons. Moreover, we reflect on our literature review to identify possible spectrum sharing design solutions and performance evaluation approaches useful for future coexistence cases. Finally, we discuss spectrum sharing design challenges and suggest future research directions