Jani Saloranta

Ultra-Wideband Signal Impact on the Performances of IEEE 802.11b and Bluetooth Networks

This paper presents the results of a coexistence study investigating the impact of ultra-wideband (UWB) interference on IEEE 802.11b and Bluetooth networks. The results are based on the experimental test measurements made at the University of Oulu, Finland. Simple high-power UWB transmitters are used to interfere with victim networks. Preliminary results show that only under extreme interference conditions with thousands of equivalent Federal Communications Commission– (FCC)-compliant devices in close proximity, will the IEEE 802.11b and Bluetooth networks experience significant performance degradation. The impact of the UWB interference on the IEEE 802.11b network was insignificant if the distance to UWB transmitters was greater than 40 cm. The impact on Bluetooth was even less noticeable. In our study, several high-power UWB transmitters that greatly exceed the FCC radiation regulations have been used, and the measurement settings presents the worst case scenario because of the very short distance between the interferers and the victim system. Effectively our study approximates the use of thousands of FCC-complaint UWB devices in the same space.

Ultra wideband signal impact on IEEE802.1 lb and Bluetooth performances

This paper presents the results of a co-existence study investigating the impact of ultra wideband (UWB) interference on IEEE802.11b and Bluetooth networks. Results are based on the experimental test measurements made at the University of Oulu, Finland using simple high power UWB transmitter prototypes as interference sources. Preliminary results showed that, under the extreme conditions of this experiment, both IEEE802.11b and Bluetooth networks will slightly suffer from the existence of several high proximity UWB signals. In our study, several high power UWB transmitters that greatly exceed the FCC radiation regulations have been used, and the measurement settings presents the worst case scenario due to the very short distance between the interferers and the victim system. Effectively our study indicates the use of hundreds of FCC compatible UWB devices at a same space.

Solving the fast moving vehicle localization problem via TDOA algorithms

We consider an anchor-free source-localization problem relevant to the control of fast moving vehicles, approaching a stop located indoors (stations, tunnels, warehouses, etc). A peculiarity of the problem is that both the location of fixed devices (access points) and the trajectory of the target (vehicle) are unknown. Two time-difference-of-arrival (TDOA)-based weighted least-squares (WLS) methods are considered to solve this problem are presented.

An Experimental Evaluation of WiFi-Based Vehicle-to-Vehicle (V2V) Communication in a Tunnel

New automated solutions are needed, e.g., in mining industry to improve efficiency and productivity of every process. In addition, costs have to be reduced, and health and safety of employees need to be enhanced. This paper studies vehicle-to-vehicle (V2V) communication to be utilized in, e.g., mining vehicles in a tunnel to increase safety and productivity of a transportation of mining goods. The objective of the paper is to experimentally evaluate maximum achievable range of WiFi radio in a real tunnel environment including line-of-sight (LOS) and non-LOS (NLOS) links. The measurement campaign was carried out in an artificial tunnel using commercial off-the-shelf WiFi radios and antennas. The experimental system was able to reach 150 m range when applying a single data stream, and 100 m for two simultaneous data streams without loss in throughput.

Interval-scaling for multitarget localization

In this paper we illustrate the potential of the generic I-SCAL framework for localization. Much like algebraic Multidimensional Scaling, which was originally utilized in other fields of science until it was identified as suitable for localization, I-SCAL is a SMACOF optimization-based generic framework which, to the best of our knowledge is here, for the first time, employed to solve the localization problem. To do so we propose to modify the rectangular objects employed in the standard I-SCAL framework with circular ones, resulting in faster and better performing algorithm in standard localization scenario. In addition it is shown that the computational complexity be further reduced by means of a vector extrapolation stage added in the optimization stage. The application of the proposed algorithm to the two standard localization scenarios here considered shows that the I-SCAL algorithm outperforms the SMACOF algorithm.

Comparison of different beamtraining strategies from a rate-positioning trade-off perspective

In next generation of mobile networks, the 5G, millimeter-wave communication is considered one of the key technologies. It allows high data rate as well as the utilization of large antennas for massive multiple-input-multiple-output (MIMO) and beamforming. However, it is mandatory that transmitter and receiver perform a training of their beams in order to gain all the benefits of a large array gain. In this paper, we study the impact of the beamtraining overhead on the data rate when an exhaustive or hierarchical strategy is used. Also, we show that the beamtraining phase can be used for positioning and, in this regard, we study the trade-off between positioning and data rate.

On the utilization of MIMO-OFDM channel sparsity for accurate positioning

Recent results have revealed that MIMO channels at high carrier frequencies exhibit sparsity structure, i.e., a few dominant propagation paths. Also channel parameters, namely angular information and propagation delay can be modelled with the physical location of the transmitter, receiver and scatters. In this paper, we leverage these features into the development of a single base-station localization algorithm, and show that the location of an unknown device can be estimated with an accuracy below a meter based on pilot signalling with a OFDM transmission. The method relies on the utilization of the “Adaptive-LASSO” optimization method, in which an ℓ1-based minimization problem is solved by adapting the sparsifying matrix (dictionary) and the sparse vector jointly. Then the location of the device is estimated from the parameters of the sparsifying matrix. Finally, the positioning method is evaluated in different channel setting utilizing a ray-tracing channel model at 28GHz.

Emulation of secure Wi-Fi communication: A performance gap analysis against a virtual test-bed

Wireless local area networks (WLANs) gained evergrowing importance in public transportation systems where they are selected to reduce installation costs and introduce new services. However, the introduction of a wireless interface in safety critical applications implies different communication protocol analysis and the introduction of a security layer is indispensable to implement defenses from malicious attacks. Host Identity Protocol (HIP) based network with IPSec is the network architecture proposed to secure wireless communications in large public transportation system. This paper analyses a comparison between the proposed architecture tested in a real environment and in an emulated scenario. The measurement campaign was carried out in outdoor using commercial on the shelf (COTS) Wi-Fi devices. The Common Open Research Emulator (CORE) with the Extendable Mobile Ad-hoc Network Emulator (EMANE) framework were used to evaluate the same scenario in a virtual test-bed. Results indicate how the end-to-end secure wireless communication built in the emulator works similarly to an intra-vehicular on-board network.

Robust 3D MIMO-OFDM channel estimation with hybrid analog-digital architecture

We consider the problem of 3D multiple-input-multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) channel estimation, a key for the future development of 3D beamforming techniques. Our main contribution is a novel algorithm, namely the adaptive-LASSO, that can jointly exploit the sparsity structure of the MIMO-OFDM channel in the spatial and delay domains. The algorithm is designed to handle large antenna arrays by means of a hybrid analog-digital architecture. In this regard, we describe an effective beam-switching strategy to sample the channel using a few analog beamformers. We investigate the impact of the signal bandwidth, antenna structures, line-of-sight (LOS) and non-line-of-sight (NLOS) conditions via ray-tracing based simulations. Also, we show that the A-LASSO can provide significant improvements with respect to the legacy methods, e.g. least-square technique.

Security of Wi-Fi on-board intra-vehicular communication: Field trials of tunnel scenario

Wireless communications are increasingly-often selected as a cable replacement for on-board vehicular networks. When a wireless technology implements safety critical application, cryptographic countermeasures are required. This paper describes the impact of security on intra-vehicular communication in a real tunnel scenario, e.g. for urban transit or mining vehicles where the usage of security is mandatory in order to maintain the system safety. The measurement campaign was carried out in a sport ski-tunnel using commercial off-the-shelf (COTS) Wi-Fi modules. The objective was to understand the impact of overhead on security in a tunnel considering line-of-sight (LOS) and non-LOS (NLOS) scenarios. In addition, the study compared different solutions for security to evaluating lesser known protocols. These field trials showed that wireless security is feasible up to 300 m in NLOS without repeaters. Finally, the experiment presented confirms the effectiveness of the Host Identity Protocol when used as standalone or in combination with other security solution.