References of "Zetterberg, Per"
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See detailInvestigation of Simple Algorithms for Estimation of Delay-Spread and Angle-Spread
Zetterberg, Per; Jaldén, Niklas; Ottersten, Björn UL et al

Scientific journal (2012)

In this paper we describe two simple methods for estimation of delay-spread and angle-spread, respectively. The algorithms are simple in the sense that the transmitted signal may consist of only three ... [more ▼]

In this paper we describe two simple methods for estimation of delay-spread and angle-spread, respectively. The algorithms are simple in the sense that the transmitted signal may consist of only three superimposed CW tones -and the receiver need only two antennas. The algorithms are also simple in the sense that the computational cost is very low. We verify the algorithms by applying them to wideband and multi-antenna measurement data, respectively. [less ▲]

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See detailModelling Angle Spread Autocorrelations and the Impact on Multi-User Diversity Gains
Jalden, Niklas; Zetterberg, Per; Ottersten, Björn UL

in Wireless Communications and Networking Conference (WCNC), 2010 IEEE (2010)

One way of modelling the wireless channel is in a statistical manner, based on a few parameters describing the characteristics of the environment. In most current wireless channel models, these key ... [more ▼]

One way of modelling the wireless channel is in a statistical manner, based on a few parameters describing the characteristics of the environment. In most current wireless channel models, these key parameters are assumed independent between separate links, i.e. on the channels modelling the propagation between one base station and several mobile stations, or one mobile station and several base stations. In practice, dependencies between these wireless channels is expected and as a consequence, system performance evaluations based on models with independent links may be inaccurate. Herein, we consider simulations of a system that depend on the spatial nature of the channel. In particular, we study a system with multi-user scheduling using a single carrier. We investigate the impact of angle spread correlations on multi-user diversity gains using opportunistic scheduling. To facilitate this, a novel method of modelling the angle spread correlations for multi-user system simulations is developed. It is shown that in systems with multiple user scheduling, modelling the angle spread autocorrelation is necessary to obtain reliable system performance results, especially as the number of simultaneous scheduled users increases. [less ▲]

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See detailCross Layer Implementation of a Multi-User MIMO Test Bed
Jalden, Niklas; Bergman, Svante; Zetterberg, Per et al

in Wireless Communications and Networking Conference (WCNC), 2010 IEEE (2010)

This paper describes an implementation of a realtime multi-user multiple-input multiple-output (MU-MIMO) communication system, with cross-layer channel-aware scheduling. The system is implemented using ... [more ▼]

This paper describes an implementation of a realtime multi-user multiple-input multiple-output (MU-MIMO) communication system, with cross-layer channel-aware scheduling. The system is implemented using software reconfigurable nodes that may be configured as either user terminals, or as base stations, communicating in the GSM 1800 uplink band. Three different commonly used scheduling algorithms (based on channel state information fed back by the receiver nodes) are studied and compared experimentally for three different signal to noise ratios in an indoor non line of sight environment. It is shown that channel-aware scheduling increases not only the system throughput, but also the fairness. Further, using the possibility of changing antenna polarization through software controlled switches, the multiuser gains may be increased even further, both in total throughput as well as fairness. [less ▲]

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See detailDirectional Dependence of Large Scale Parameters in Wireless Channel Models
Jalden, Niklas; Zetterberg, Per; Ottersten, Björn UL

in IEEE Wireless Communications (2008)

In this paper the autocorrelation properties of shadow fading and angle spread at both the base station (BS) and at the mobile station (MS) are analyzed using urban macro cellular measurement data. The ... [more ▼]

In this paper the autocorrelation properties of shadow fading and angle spread at both the base station (BS) and at the mobile station (MS) are analyzed using urban macro cellular measurement data. The shadow fading parameter is shown to have a longer decorrelation distance than the angle spread at both the BS and at the MS. Furthermore, we observe variations in the shadow fading that depend on the direction of the MS movement. The same dependence is not observed in the angle spreads. These results indicate that the origin of the angle spread is local to the transmitter and receiver, while the shadow fading depends on the intermediate environment. [less ▲]

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