Implementation av en Bluetooth antenn för ett mobiltelefontillbehör

In this thesis the possibility of implementing a Bluetooth antenna in a mobile phone accessory with a metallic surface is investigated. The antenna is implemented in such a way that the metal surface will act as the radiating element. Mobile phone accessories are often small in size and require an antenna that does not require much space. The small size sets performance limits such as low bandwidth and efficiency for an antenna and a good performance in a changing environment can be difficult to achieve. Antenna performance is often directly related to the volume of the antenna structure. By implementing the antenna onto a metal chassis the entire surface of the product is in use and thus better performance can be achieved. The optimal antenna models and dimensions are found through theoretical analysis and simulations. Antenna performance was evaluated by examining the impedance bandwidth and radiated and total efficiency. The smallest dimensions that limit the performance of the antenna were also investigated for a few possible solutions. If the metal surface of a mobile phone accessory is used as a Bluetooth antenna, the small antenna limitations are usually not a problem and the antennas can be made very broadband and efficient. Drawbacks that are related to metal cover antennas are performance in use position and the difficulty of implementing the feed structure of the antenna. Two dipole antennas and one slot antenna are made based on the most promising simulations. The dipole antennas have very wide impedance bandwidth and have quite good performance in use position. Comparing with the dipoles the slot antenna has got narrower impedance bandwidth and also performs worse in use position, but still, it fulfils the performance requirements

Multi-User Channel Estimation Exploiting Pulse Shaping Information

A method for joint estimation of wireless communication channels to multiple users utilizing pulse shaping knowledge is presented. The pulse shaping in the transmitter and the receiver is incorporated into the channel estimation by approximating it with a set of pulse shaping functions. In joint multi-user channel estimation the number of parameters to be estimated grows linearly with the number of users while the number of equations remains constant. Utilizing the pulse shaping information is therefore especially useful since this economizes on the number of parameters to be estimated per user. This is illustrated with a multi-user channel estimation example. 1. INTRODUCTION A wireless communication system is often interference limited, i.e. the signal quality is limited because of cochannel interference rather than because of noise. If the channels to the interfering signals can be estimated jointly with the desired signal, the channel estimates of the desired signal as well as of ..

Design And Evaluation Of A Fully Adaptive Antenna For Telecommunication Systems

An adaptive antenna for the DCS-1800 mobile telephony system has been designed and evaluated. The antenna is working in uplink only and has a multiplexity of two channels per frequency and timeslot. The array antenna has a circular structure and the complex weights are calculated using the sample matrix inversion method (SMI). Evaluations of the adaptive antenna in an outdoor environment show promising improvement of the carrier-to-interfererratio (C/I) of more than 30 dB. Measurements of bit-error-rate (BER) for different angular separation of the mobiles show that for an input C/I ³ -10 dB the minimum angular separation for approximately 0% BER is less than 4 degrees. INTRODUCTION The use of adaptive antennas in mobile communication systems offers a possibility to increase the system capacity. To exploit the benefits of using adaptive base station antennas, a testbed project commenced 1994 consisting of groups at the Signals and Systems group at Uppsala University and Ericsson Radio..

Experimental Evaluation of an Adaptive Antenna for a TDMA Mobile Telephony System

Measurements of an adaptive DCS-1800 base station antenna, used in uplink only, are presented and analysed. Both laboratory measurements and outdoor field trials have been performed. The antenna is improving the C/I ratio more than 30 dB. Calculations using measured data, assuming downlink performance equal to that of the uplink, show a spectral efficiency gain of 6 over present base station systems. INTRODUCTION The number of users in mobile telephony systems is dramatically increasing. A proposed method to increase the number of voice channels per available bandwidth and square kilometre is to introduce adaptive array antennas, where suppression of co-channel interferers and spatial multiplexing is made available. A testbed project commenced 1994 at Uppsala University and Ericsson Radio Access AB. The aim is to evaluate and develop adaptive antenna technologies for mobile communication systems and to obtain experience using this technology in base stations. Other testbed projects h..