Harri Viittala

European Telecommunications Standard Institute (ETSI) Technical Committee (TC) Smart Body Area Network (SmartBAN) defines and specifies low-power physical and medium access control layers for SmartBANs. Several use cases have been defined for SmartBAN, such as sleep monitoring, fall monitoring, and apnea monitoring. The specialist task force 511, working under ETSI TC SmartBAN, studied the performance of the system and evaluated coexistence with other wireless systems. In this paper, the simulator model based on the SmartBAN specification is introduced. Based on the simulation results, the receiver sensitivity for the SmartBAN system is defined. In addition, the interference model extracted from the measurements in the Oulu university hospital is discussed. This paper presents the summary of the simulation results based on the above-mentioned interference models. The simulation results showed that when there is a high interference in a communication channel, the SmartBAN system cannot gain an acceptable frame error level without a physical layer protocol data unit repetition technique and a high signal-to-interference power ratio level (SIR). In a low interference scenario, repetition is also needed when SIR is less than 9 dB.

The ETSI TC SmartBAN defined system is designed for body area networks supporting both on-body links and links to implanted devices. The system operates at the 2.4 GHz ISM band, where there are also other wireless radio systems, such as Bluetooth and WiFi. The SmartBAN system simulation model has been created to Matlab and the system performance was studied in the IEEE 802.15.6 channel model 3 with a measurement based interference model. The interference model is based on the measurement campaigns carried out in the Oulu university hospital. By using these simulation models, comparative analysis between BCH encoding schemes (127,113) and (36,22) on the system performance was carried out. It is shown that a higher coding rate has better performance in the presence of interference but it needs a repetition method to gain an acceptable frame error rate.

Heterogeneous nature of Wireless Body Area Networks (WBANs) including different types of nodes, applications and environments sets great challenges for a routing protocol. We will present routing challenges set by WBAN and its applications, go through existing protocols and their flaws. In the end, we will give a novel routing protocol using different zones and fuzzy logic.

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.

An experimental evaluation of 802.11g+n based wireless local area network (WLAN) devices with omnidirectional and directive antennas under interference is investigated in this paper. The performance of directive antennas is known to be better if the interference signal is coming from the sidelobes' directions. Here we studied the performance difference between directive and omnidirectional antennas when the interference signal is originated between a transmitter and a receiver.

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.

In this paper, the performances of two singleband ultra wideband (UWB) systems, i.e., direct sequence UWB (DS-UWB) and UWB frequency modulation (UWB-FM) are studied in two different channel models to reveal an impact of a channel model on the system's performance. The applied channel models are the experimental wireless body area network (WBAN) channel model developed at the Centre for Wireless Communications (CWC), Finland, and the IEEE 802.15.6 channel model. The simulation results indicate that the choice of the WBAN channel model applied in the simulations has a major impact on the performance of UWB-FM, whereas it is not such a crucial in the case of DS-UWB.

In order to find the best solution of physical layer for medical wireless body area network (WBAN), two single-band ultra wideband (UWB) systems are studied, i.e., direct sequence ultra wideband (DS-UWB) and ultra wideband frequency modulation (UWB-FM). UWB is considered to be one of the most feasible techniques among those that can be applied to medical WBAN since it provides low power consumption, simple transceiver structure and good coexistence characteristics due to a low power spectral density. The simulation results indicate that UWB-FM has better performance than non-coherent DS-UWB in overall. It was expected that coherent DS-UWB with multiple rake fingers gives the best results, and this was justified by the simulation results.