A Novel Bitrate Adaptation Method for Heterogeneous Wireless Body Area Networks

In the article, a novel bitrate adaptation method for data streams allocation in heterogeneous Wireless Body Area Networks (WBANs) is presented. The efficiency of the proposed algorithm was compared with other known algorithms of data stream allocation using computer simulation. A dedicated simulator has been developed using results of measurements in the real environment. The usage of the proposed adaptive data streams allocation method by transmission rate adaptation based on radio channel parameters can increase the efficiency of resources’ usage in a heterogeneous WBANs, in relation to fixed bitrates transmissions and the use of well-known algorithms. This increase of efficiency has been shown regardless of the mobile node placement on the human body.

An Empirical System Loss Model for Body Area Networks in a Passenger Ferry Environment

P. Kosz , S. Ambroziak , J. Stefański , K. Cwalina , L. Correia, K. Turbic – 2018
This paper presents a general empirical system loss model for estimating propagation loss in Body Area Networks in off-body communications at 2.45 GHz in a passenger ferry environment. The model is based on measurements, which were carried out in dynamic scenarios in the discotheque passenger ferry environment. The model consists of three components: mean system loss, attenuation resulting from the variable antenna position on the human body, and attenuation due to fading. Preliminary results for system loss components in dynamic scenarios in the discotheque environment are presented. The components of mean system loss and variable antenna position attenuation are modelled by using a linear regression. The obtained root mean square error for the mean system loss is lower than 5 dB. The fading components are modelled by Lognormal and Nakagami-m distributions.

An Empirical System Loss Model for Body Area Networks in a Passenger Ferry Environment

P. Kosz , S. Ambroziak , J. Stefański , K. Cwalina , L. Correia, K. Turbic – 2018
This paper presents a general empirical system loss model for estimating propagation loss in Body Area Networks in off-body communications at 2.45 GHz in a passenger ferry environment. The model is based on measurements, which were carried out in dynamic scenarios in the discotheque passenger ferry environment. The model consists of three components: mean system loss, attenuation resulting from the variable antenna position on the human body, and attenuation due to fading. Preliminary results for system loss components in dynamic scenarios in the discotheque environment are presented. The components of mean system loss and variable antenna position attenuation are modelled by using a linear regression. The obtained root mean square error for the mean system loss is lower than 5 dB. The fading components are modelled by Lognormal and Nakagami-m distributions.

An Off-Body Narrowband and Ultra-Wide Band Channel Model for Body Area Networks in a Ferry Environment

In the article an off-body narrowband and ultra-wide band channel model for Body Area Networks in a ferry environment is described. A mobile, heterogeneous measurement stand, that consists of three types of devices: miniaturized mobile nodes, stationary reference nodes and a data acquisition server was developed. A detailed analysis of both radio channels parameters in untypical indoor environment was carried out. An analysis of system loss for off-body communication, including mean system loss, slow fading component (corresponding to body shadowing) and fast fading component (associated with the multipath phenomenon), both for the 868 MHz narrowband and for the 6489 MHz ultra-wide band channels, was performed. Obtained system loss exponent values are in the range of [0.13; 0.85] for line-of-sight conditions, and [1.25; 3.46] for non-line-of-sight conditions. For the investigated environment the lognormal distribution was found to be the best describing the slow and fast fading, regardless of the frequency band and on-body antenna placement. A statistical analysis of the model parameters was also carried out and its good matching to the empirical data was proved.

An Off-Body Narrowband and Ultra-Wide Band Channel Model for Body Area Networks in a Ferryboat Environment

In the article an off-body narrowband and ultra-wide band channel model for body area networks in a ferryboat environment is described. Considering the limited number of publications there is a need to develop an off-body channel model, which will facilitate the design of radio links, both from the multimedia services provider and the security point of view, for body area networks in this atypical environment. A mobile heterogeneous measurement stand, using radio distance measurements, which consists of three types of devices: miniaturized mobile nodes, stationary reference nodes, and a data acquisition server, was developed. A detailed analysis of both radio channels’ parameters was carried out. An analysis of system loss for off-body communication, including mean system loss, large-scale fading (corresponding to body shadowing), and small-scale fading (associated with the multipath phenomenon), both for 868 MHz narrowband and for 6489 MHz ultra-wide band channels, was performed. A statistical analysis of the obtained system loss model parameters was also carried out; good fit to the empirical data is observed.

ANALIZA UWARUNKOWAŃ PROPAGACYJNYCH W RADIOWYCH SIECIACH BAN Z PRZESTRZENNYM ODBIOREM ZBIORCZYM

W referacie przedstawiono analizę uwarunkowań propagacyjnych w radiowych sieciach BAN typu off-body z odbiorem zbiorczym przestrzennym. Średnia wartość tłumienia znajduje się w przedziale [54.42 dB; 64.28 dB], różnica wartości tłumienia dla anten nasobnych wynosi [0.69 dB; 8.76 dB], odchylenie standardowe tłumienia średniego zawarta jest w przedziale [6.46 dB; 7.39 dB], natomiast współczynnik korelacji pomiędzy zanikami szybkozmiennymi sygnałów odebranych przez anteny nasobne dla każdego scenariusza jest bliski 0.

Badania i analiza zaników w sieciach WBAN typu body-to-body pracujących w różnych środowiskach propagacyjnych

Przedstawiono badania zaników w sieciach WBAN typu body-to-body, oparte na wynikach pomiarów tłumienia systemowego przeprowadzonych w zamkniętym i otwartym środowisku propagacyjnym przy częstotliwości 2,45 GHz. Analiza statystyczna wyników dowiodła, że zaniki szybkozmienne najlepiej odzwierciedla rozkład Nakagamiego-m, natomiast zaniki wolnozmienne można opisać rozkładem log-normalnym.

Badanie i analiza efektu cienia radiowego w sieciach WBAN typu off-body i body-to-body

W referacie zaprezentowano prosty model matematyczny, opisujący efekt cienia radiowego powodowany przez ciało ludzkie w sieciach WBAN typu off-body i body-to-body. Model ten oparty jest na charakterystyce cienia radiowe-go w postaci funkcji kosinusoidalnej z empirycznie wyznaczonym parametrem amplitudy (maksimum charaktery-styki cienia radiowego), który – jak dowiedziono – jest liniowo zależny od odległości między anteną nasobną a zewnętrzną. Model został zweryfikowany na podstawie danych empirycznych dla częstotliwości 2,45 GHz, zgromadzonych podczas pomiarów w środowisku zamkniętym.

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

W referacie zaprezentowano empiryczny model do szacowania tłumienia systemowego dla radiowych sieci BAN pracujących w środowisku promu pasażerskiego przy częstotliwości 2,45 GHz dla komunikacji typu off-body. Badania pomiarowe przeprowadzono dla scenariuszy dynamicznych w pomieszczeniu dyskoteki promu pasażerskiego. Postać analityczna modelu składa się z trzech składowych: tłumienia średniego, tłumienia wynikającego ze zmiennej pozycji anteny na ciele człowieka oraz tłumienia wynikającego z występowania zaników sygnału radiowego.

Fading Characteristics for Dynamic Body-to-Body Channels in Indoor and Outdoor Environments

K. Turbić, S. Ambroziak , L. Correia – 2018
This paper presents an analysis of the fading characteristics in dynamic body-to-body channels, based on measurements performed at 2.45 GHz in indoor and outdoor environments. The statistical analysis of the small- and large-scale fading shows that the Nakagami Distribution is the best model for the former and the Log-Normal one for the latter. An important influence of body shadowing on the small-scale fading characteristics is observed, where the average amount of fading (fading merit) for the case when either of the users is obstructing the direct path is up to 2.56 times higher than when the direct path is unobstructed. The influence of the environment is also important, where small-scale fading is more severe in the indoor environment than in the outdoor one; 1.88 times higher average amount of fading and 3.81 dB lower K-factor are observed.