Robert S. Karlsson

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To decrease total system cost and improve efficiency, in future mobile communication systems, we can implement a structure of multiple cells covering an area. This is often referred to as a Hierarchical Cell Structure, HCS. We compare five methods of sharing the scarce radio resources in a two layer HCS: I) DS-CDMA in macro cells and TDMA in micro cells,(More)
— Multiband CDMA is useful for constructing DS-CDMA (CDMA) systems over a non-contiguous spectrum. The method by which users are assigned to their respective frequency bands, termed 'band allocation', is an important part of assuring good performance in multiband CDMA systems. This paper proposes a novel approach to band allocation based on the transmission(More)
The uplink random access channel will be a key part of the 3 rd generation wireless systems as it will be used for initial contact with base stations as well as for packet data transmission. In this paper, the throughput of preamble power ramping with 16 orthogonal channels currently adopted as the UTRA standard for random access is evaluated. It is shown(More)
One way to decrease total system cost and improve efficiency in future mobile communication systems is a structure with cells covering the same area. This is often referred to as a Hierarchical Cell Structure, HCS. We investigate the novel option of using Slow Frequency Hopping, SFH, to combat interference between layers in an HCS where the same spectrum is(More)
This paper studies the problem of channel estimation for the downlink in broadband LTE communications. A Kalman Filter is used to combine channel soundings made with pilot tones that are deployed at different times and in different frequency bands on a pre-selected pattern. This Kalman filter is presented in a form directly suitable for implementation as a(More)
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