802.11a channel parameters characterization on board a business jet

Up to few years ago, internet connectivity was limited to households, workplaces, or hot-spots in public places, but nowadays the idea of being online during business and commercial flights is gaining momentum. Although studies show that the main factor to differentiate between airlines is the air ticket's fare, the possibility of using portable communication devices is increasingly becoming a priority too. This has brought the European Commission to prepare the legal framework in April 2008 for wireless connectivity inside aircraft. The technology will enable passengers to communicate through their personal devices. This paper analyzes the implementation of a wireless 802.11a network inside a Dassualt business jet. A wireless architecture can be thought of one or more fixed access points (AP) and several mobile receivers. The mobile equipment used by the passengers, can be either static - when the passenger is seated, or mobile - when the passenger is moving around the aircraft. Therefore, different scenarios must be considered with the two extreme cases being all users static and all users mobile. Out of all the candidate wireless technologies that can be used for the implementation of data services, a coded orthogonal frequency division multiplexing (COFDM) based technology was selected since it offers good performance in confined spaces, such as the business jet cabin considered. COFDM can withstand frequency selective fading, hence eliminating the need of equalization at the receivers, if it is ensured that the time dispersion characteristics for the channel are below some thresholds. These thresholds are determined by the parameters of the chosen wireless architecture, such as Air5^TM, IEEE 802.11a and IEEE 802.11a. Since most of the current mobile devices have an integrated Wi-Fi card, this study focuses on the characterization of the channel for an IEEE 802.11a architecture. IEEE 802.11a operates in the 5.4GHz frequency band and can achieve a maximum data rate of 54Mbps, which is more than enough for most applications. A 3D ray tracing technique, based on Geometric Optics (GO) was used to analyze the propagation characteristics inside the Falcon business jet. The internal of the aircraft was divided into a number of cells, with each cell having very small dimensions. A large number of rays are launched from an antenna and the propagation path of each ray is followed. When a ray falls on a surface, reflection, scattering and transmission coefficients are calculated to produce two rays having a different power and phase. This process is continued until the signal's power is below a preset threshold. The power inside each cell is then vectorialy summed to estimate the received power at that point. Multipath phenomena were recorded for each location inside the cabin and from these values, the probability distributions were obtained at different locations. The power delay profile (PDP) was extracted at predetermined receiver candidate locations and hence the time dispersion characteristics were also found. This model provides more confidence that IEEE 802.11a is a promising technology for the deployment of wireless services inside a business jet.