Diversity Performance Analysis for On-Body Communication Channels at 2.45 GHz

Abstract

Body-centric communications is an important part of fourth-generation personal communications systems. Like the mobile cellular communication channel, on-body communication channels are affected by fading. In this paper, the effect of diversity for on-body communication channels is investigated. Measurements were taken in both an anechoic and typical indoor environments, with random body movements. Three different types of antennas were used. The diversity gain was calculated by plotting the cumulative distribution functions (CDF) for five body channels. Significant diversity gain values are observed for the nonline-of-sight channels and dynamic channels involving large body movements. The uplink and downlink diversity performance was found to be similar

Experimental Investigation of Ultra Wideband Diversity Techniques for on-Body Radio Communications

“…The results obtained for UWB on-body diversity at location 2 are compared with the results of Khan et al at 2.4 GHz presented in [2] in an indoor environment (comparison plot is shown in Figure 6). This is an approximate comparison; as for both measurement results, human subject and indoor environment were different).…”

“…Wireless body area networks (WBANs) mainly experience fading due to the following: relative movements of body parts; polarisation mismatch; shadowing; and diffraction and scattering from the body parts and surrounding environments [1,2]. Diversity is a powerful technique to combat fading and multipath effects [3].…”

“…The improvement due to diversity is often measured in terms of diversity gain (DG); this is basically an improvement in signal strength (or, equivalently, signal-to-noise ratio or bit-error rate) compared with that observed with a single antenna at a certain outage probability [2,3,5,7,8]. The outage probability is the probability that the system performance falls below a minimum performance threshold (typically defined in terms of signal-to-noise ratio) within a specified time period [9].…”

“…An experimental investigation of diversity antennas has been presented in [10], with results showing that, for non-line-of-sight (NLOS) scenarios, diversity gains of up to 10 dB can be achieved, at an outage probability of 1%. There are some studies presented in the open literature where the benefits of diversity techniques for on-body communications in narrow-band systems have been investigated [2,[13][14][15]. Introductory studies for on-body diversity measurements at 2.45 GHz were presented in [13].…”

“…The diversity performances were evaluated in terms of DG, power imbalance and envelope correlation coefficients between the two receiving channels. A comprehensive study of diversity for an on-body channel at 2.45 GHz was presented in [2], using different antennas and diversity types. A significant gain was observed for NLOS channels and dynamic channels involving large body movements.…”