Mikael Sternad

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A downlink radio interface is proposed for cellular packet data systems with wide area coverage and high spectral efficiency. A slotted OFDM radio interface is used, in which timefrequency bins are allocated adaptively to different users within a downlink beam, based on their channel quality. Fading channels generated by vehicular 100 km/h users may be(More)
When adaptive modulation is used to counter short-term fading in mobile radio channels, signaling delays create problems with outdated channel state information. The use of channel power prediction will improve the performance of the link adaptation. It is then of interest to take the quality of these predictions into account explicitly when designing an(More)
Loudspeakers always introduce linear and nonlinear distortions in a stereo system. It is however possible to partially cancel these distortions by digitally pre-inverting the signal. We here discuss one of several possible solutions to this problem, namely the use of a linear inverse obtained from a measured ARX loudspeaker model. The inverse is obtained by(More)
We investigate the use of an antenna array at the receiver in frequency-division multiple-access/timedivision multiple-access systems to let several users share one communication channel within a cell. A decision-feedback equalizer (DFE) which simultaneously detects all incoming signals is compared to a set of DFE’s, each detecting one signal and rejecting(More)
Low-complexity WLMS adaptation algorithms, of use for channel estimation, have been derived in a companion paper. They are here evaluated on the fast fading radio channels encountered in IS-136 TDMA systems, with the aim of clarifying several issues: How much can channel estimation performance be improved with these tools, as compared to LMS adaptation?(More)
| High data rates, high spectral efficiency, flexibility, and low delays over the air interface will be important features in next-generation wireless systems. The overall challenge will be packet scheduling and adaptive radio transmission for multiple users, via multiple antennas and over frequency-selective wideband channels. This problem needs to be(More)
Within the EU FP6 Integrated Projects WINNER and WINNER II, multiple access schemes for frequency-adaptive and non-frequency-adaptive transmission for a future broadband mobile wireless system are investigated. This paper presents a novel power efficient multiple access scheme for non-frequencyadaptive uplink transmission denoted Block Interleaved Frequency(More)
A simpliied way of deriving of realizable and explicit Wiener lters is presented. Discrete time problems are discussed, in a polynomial equation framework. Optimal lters, predictors and smoothers are calculated by means of spectral factorizations and linear polynomial equations. A new tool for obtaining these equations, for a given problem structure, is(More)