Characterization of the Dynamic Narrowband On-Body to Off-Body Area Channel

Abstract

A characterization of the dynamic narrowband onbody to off-body area channel is presented based on realtime measurements of the time domain channel response at carrier frequencies near the 900MHz and 2400MHz Industrial, Scientific and Medical (ISM) bands. A statistical characterization is presented of received signal amplitude when the subject's body is standing and walking, transmitted from the body to a receiver, Rx, off the body, with various orientations of the subject's body with respect to the receiver, and various distances from the receiver. Two locations of the transmitter, Tx, on the human body are considered. The Lognormal distribution provides a good fitting model with and without movement. Further, the stability is characterized based on a measure of channel response variance, which is called here the channel variation factor and can characterize the channel coherence time. The on-body to off-body area channel is determined to be generally stable over a period of 25ms, but the amount of stability is found to be dependent both on movement, Tx location on-body, and carrier frequency.

First- and second-order statistical characterizations of the dynamic body area propagation channel of various bandwidths

“…Overlayed on each empirical PDF is the PDF of the best fit for four distributions. 6 It is noteworthy that in all these cases the best fits are either Weibull or Gamma distributions; in all cases, the best-fitting distributions, with parameters given in Table 2, provide good fits, as evidence in the figures for on-body measurements. It is of special note that in Fig.…”

Physical-Statistical Channel Model for Off-Body Area Network

“…The measurements were conducted in an anechoic chamber, and Lognormal and Ricean distributions were used to model the path-loss. In [7], similar studies were conducted in an indoor environment where Lognormal distribution proved to be a good fit in describing the normalized signal amplitude. Further studies were conducted in [8] in which also the impact of antenna polarization on channel characteristics was investigated.…”

“…Unlike the models in [6][7][8], which are purely empirically based and applicable only in the environments similar to the measurement site; we propose a more accurate physicalstatistical based channel model for off-body communications. Generally, physical-statistical models are more accurate than merely empirical models as they rely on electromagnetic based methods for calculating the needed model parameters.…”

Analysis of Absorption Loss by a Human Body in On-to-Off Body Communication at 2.45 GHz

“…For several years, many efforts have been made to identify the propagation characteristics in on-to-off body communication [1][2][3][4]. In indoor environments, the log-normal and Rayleigh distributions provide good fit to the on-to-off body channels for standing and for walking, respectively [1].…”

“…In indoor environments, the log-normal and Rayleigh distributions provide good fit to the on-to-off body channels for standing and for walking, respectively [1]. Smith et al [2] showed that the on-to-off body channels for sleeping persons follow the Gamma distribution.…”