Showing papers by "Preben Mogensen published in 1995"

An advanced base station receiver concept for DECT

Abstract: The concept of a simple non-coherent equaliser receiver for DECT, as a means to obtain robust performance in outdoor and large indoor applications is discussed. This simple structure renders the receiver insensitive to dispersion but cannot substitute diversity in flat fading channels. The authors describe practical approaches leading to a high performance base station receiver for DECT-type systems, based on the above concept. It is shown that a significant portion of the DECT preamble is not required by the present equaliser receiver, and that this interval can be used to emulate ideal selection diversity (without the need for two parallel receivers). In addition, the authors also introduce an approach to further extend the receiver's frequency offset tolerance. They therefore propose a novel integrated structure that performs both equalisation and selection diversity in a single base station receiver. It is shown through simulation that this receiver provides robust radio performance.

Evaluation of an advanced receiver concept for DECT

Abstract: An advanced DECT receiver concept that is based upon a non-coherent differential detection with equalization, and includes switching diversity with performance of true RSSI selection diversity, has been previously described (Safavi et al., 1995). This paper deals with a hardware testbed evaluation of the concept. The analysis includes practical implementation aspects, performance results obtained from a wideband channel simulator, and measurements conducted in a typical DECT telepoint environment.

Evaluation of optimum diversity combining in DECT

Abstract: Optimum diversity combining in a wireless communications system using TDMA/TDD is considered. By the use of optimum diversity combining a receiving antenna array is able to suppress interference and thus the capacity of the system is increased. The results in this paper are obtained by simulations. In the simulations a DECT-like system is used as the TDMA/TDD system. The results show that in the uplink direction M-1 interferers can be suppressed by an M element array. However the downlink transmit diversity performance is much worse, due to the changes in the radio channel during the dwell time between the uplink and downlink burst. That is the reason why it is concluded that optimum diversity combining is only useful for a TDD system with a short dwell time.

A hierarchy of receiver options for DECT systems

Abstract: The DECT system is targeted at a large range of different applications, which have widely differing radio conditions. These can vary from short range line of sight indoor systems to relatively hostile outdoor environments. This contribution presents and discusses a range of matching options for the radio receiver, with particular emphasis on possible structures for space diversity operation and various options for equalisation. Illustrations of performance obtained by both software simulation and hardware testing are included. It is concluded that the DECT standard allows manufacturers to make technology choices suitable to the applications of interest. This includes even demanding outdoor environments where advanced processing can be used to obtain robust performance with relatively low complexity.