Kenan Turbic

An Off-Body Channel Model for Body Area Networks in Indoor Environments

This paper presents an off-body channel model for body area networks (BANs) in indoor environments. The proposed model, which is based on both simulations and measurements in a realistic environment, consists of three components: mean path loss, body shadowing, and multipath fading. Seven scenarios in a realistic indoor office environment containing typical scatterers have been measured: five were static (three standing and two sitting) and two dynamic (walk in a fixed place and real walk). The measurement equipment and measurement procedures are described. The mean path loss component is modeled as a log function of distance, the path loss exponent being in the range between 0.4 and 1.6, while a statistical perspective is taken for the other two components, i.e., body shadowing is found to be well modeled by a log normal distribution and multipath fading by Rice or Nakagami-m distributions, depending on body motion characteristics. The correlation between the selected distributions and empirical data is not lower than 0.95, typically being greater than 0.98. The novelty of this model is that it takes the statistical influence of various parameters and features present in BANs into account, such as body influence, placement of the wearable antennas, user orientation in the environment, dynamism of the BAN scenario, and propagation conditions.

Radio channel measurements in body-to-body communications in different scenarios

This paper presents body-to-body radio channel measurements at the 2.45 GHz band, for different body motion scenarios and on-body antenna placements, and both indoor and outdoor environments. Measurement equipment, investigated scenarios and considered environments are described, an initial analysis of results being presented. The mean path loss and the standard deviation depend on the mutual location of transmitting and receiving antennas, type of dynamic scenarios and investigated environments. In general, the lowest mean path loss value (below 57 dB) is obtained for the scenario where two bodies are walking in the same direction along parallel routes and the distance in between bodies equals 1 m; in contrast, the highest value (over 70 dB) is observed for the scenario where both bodies depart from each other being turned back to back. Moreover, the highest standard deviation value (over 13 dB) is obtained for scenarios with antennas mounted on the wrists, which are the most movable parts of the body while walking, and the lowest value (around 2 dB) has been measured for antennas mounted on the head.

Empiryczny model tłumienia systemowego w łączu radiowym sieci BAN pracującej w środowisku promu pasażerskiego

W referacie zaprezentowano empiryczny model do szacowania tlumienia systemowego dla radiowych sieci BAN pracujących w środowisku promu pasazerskiego przy czestotliwości 2,45 GHz dla komunikacji typu off-body. Badania pomiarowe przeprowadzono dla scenariuszy dynamicznych w pomieszczeniu dyskoteki promu pasazerskiego. Postac analityczna modelu sklada sie z trzech skladowych: tlumienia średniego, tlumienia wynikającego ze zmiennej pozycji anteny na ciele czlowieka oraz tlumienia wynikającego z wystepowania zanikow sygnalu radiowego.

An approach to mean path loss model estimation for off-body channels

This paper presents an approach to the estimation of mean path loss model parameters in off-body Body Area Networks channels. In this approach, the path loss exponent is constrained to a value obtained from line-of-sight (LoS) propagation in the copolarised channel, considering a generalised static scenario. The proposed approach is compared to alternative ones, by evaluating the coefficient of determination for a set of measurements obtained in an indoor environment. Compared to a traditional approach, a relative improvement of up to 0.7 and typically above 0.4 is observed in the LoS case, while the goodness of fit is unchanged for the non-LoS case.