| Along with the rapid development of kinds of wireless communications technologies, such as RFID, Zigbee, Bluetooth3.0 and 60 GHz millimeter wireless communication etc., short-range wireless applications taking WPA(Wireless Personal Area) as the characteristic got the extensive study and has become more and more wide in various fields.Power management, link budget and the analysis of delay profile for low and high throughput wireless applications are the key technologies for short-range wireless communications, since the characteristics of high speed and high throughput or low speed but high reliability for short-range wireless communication systems. There are many factors important to these key technologies, but propagation channel, which is the path of radio wave propagation, is more crucial. Although radio waves are propagated with reflection, diffraction and scattering, the wireless radio channel poses a severe challenge as a medium for reliable short-range communication. It is not only susceptible to noise, interference, and other channel impediments, but these impediments change over time in random way due to transceivers movement. How to overcome these challenges and resolve the problems existing in those key technologies are the main purpose of this research.Based on above analyses, the main works and contributions of the thesis include:1. The wireless propagation channel modeling and channel parameters extraction for short-range radio wave propagation are analyzed based on narrowband and wideband propagation channel model. The comparisons of channel modeling in time domain and in frequency domain are conduct. Channel sounding in frequency domain is analyzed especially, since its feature of short-range measurement. The principle, process, and postprocess are analyzed and summarized.2. Radio wave propagation researches are performed at 2.4 GHz and 5.8 GHz both are ISM frequency bands and are usually used in short-range wireless applications under radio and microwave frequency bands. The goal is to determine short-range propagation channel properties and models that suitable to characterize propagation channel for RF and microwave frequency bands.3. A two-way power management algorithm based on real-time path loss of propagation channel was implemented and validated in a point-to-point wireless system worked at 2.45 GHz. The performance of the power management are testified and evaluated by theoretical analysis and indoor measurements. It is shown that the proposed algorithm can prolong the battery lifetime effectively and adjust the transmitting power dynamically in different short-range multipath environments.4. A calculation approach for tag range of passive microwave RFID based on a multi-ray model are proposed. We show the relationship between the tag range and the reflection coefficients of the tagged object material. The distance-dependent reflection coefficients are proposed, especially when the thickness of the object surface is comparable to the wavelength. A precise simulations based on the 3-D physical finite element model is taken to verify the validity of the approach.5. A site-specific desktop propagation model is presented for IEEE 802.15 TG3c 60 GHz WPA. The reflection coefficients versus Tx-Rx separation distance using vertical and horizontal polarization are investigated. Path loss data are then computed using improved two-ray propagation model. Obtained values are compared with the measured data published in IEEE 802.15 TG3C and shown to have a more precise fitting than that predicted by conventional model.Theoretical analysis and modeling for short-range wireless propagation channel are taken in the investigation. Algorithms and models are proposed based on the short-range propagation channel. The validity of the algorithms and models are verified by the theoretical analyses, measurements, and simulations.
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