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Wireless Body-Centric Communications in Populated Environments
Investigators: Ameen J. Ali, Simon Cotton & William Scanlon
The main aim of this project is to investigate the effect of pedestrian movements on wireless body-centric communications systems
in populated environments and examine possible mitigation techniques.
The work features a novel narrowband wireless bodyworn measurement receiver system that makes synchronized RSSI measurements
at two frequencies (2.45 and 5.8 GHz bands) simultaneously.
Wireless Body Area Networks (WBAN) have illimitable applications such as location tracking, ambulatory physiological monitoring, collaborative mood-sensing etc. spanning commercial, military and medical sectors. Diversity combining techniques help mitigate some deleterious-effects of human body-shadowing and time-varying fading to provide good signal quality and reliability.
Investigation Topics
- Design of narrowband wireless wearable measurement receiver system
- Extensive measurements of on-, off- and body-to-body WBAN channels in range of populated environments
- Comprehensive statistical channel characterization and modelling of WBAN channels with pedestrian effects
- Investigation of methods to combat body-shadowing effects
Results
Human-activity such as breathing, movements of personnel, equipment etc.
in the vicinity of a wireless wearable communications system results in multipath perturbations and temporal fading effects in the received signal characteristics.
Spatial-diversity proved to be a strong-candidate to overcome these effects.
The figure on the left shows that selection combining two-branch diversity gain values improved as the human-traffic increased in the locality
The following points were observed from the measurement-campaign and analysis in the course of this study:
- Cross-correlation coefficient value between branches was always less than 0.7, irrespective of the number of pedestrians involved, sufficiently uncorrelated.
- Difference in mean signal level (DIMSL) between branches generally decreased as the number of pedestrians increased
Publication Output
- A.J. Ali, S.L. Cotton & W.G. Scanlon, 'Spatial diversity for off-body communications in an indoor populated environment at 5.8 GHz,' to be presented at Loughborough Antennas & Propagation Conf., Nov. 2009
Support
This project is funded by a School of Electronics, Electrical Engineering & Computer Science Special Research Scholarship.