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Results 681-700 of 763.
  Feedback Reduction in Uplink MIMO OFDM Systems by Chunk Optimization; ; Ottersten, Björn  et alin EURASIP Journal on Applied Signal Processing (2008) Detailed reference viewed: 131 (0 UL)Guaranteed Performance Region in Fading Orthogonal Space-Time Coded Broadcast Channels; Ottersten, Björn ; et alin EURASIP Journal on Wireless Communications and Networking (2008) Detailed reference viewed: 138 (1 UL)Capacity and Gain Analysis of a Reconfigurable MEMS Antenna; ; et al in Nordic Conference on Radio Science and Communications (RVK) (2008) Detailed reference viewed: 112 (0 UL)Feedback Reduction in Uplink MIMO OFDM Systems by Chunk Optimization; ; Ottersten, Björn et alin IEEE International Conference on Communications (ICC) (2008) Detailed reference viewed: 127 (0 UL)Feedback design in multiuser MIMO systems using quantization splitting and hybrid instantaneous/statistical channel information; ; et al in Proceedings ICT Mobile and Wireless Communications Summit (2008) In the design of next generation multiuser communication systems, multiple antenna transmission is an essential part providing spatial multiplexing gain and allowing efficient use of resources. A major ... [more ▼] In the design of next generation multiuser communication systems, multiple antenna transmission is an essential part providing spatial multiplexing gain and allowing efficient use of resources. A major limiting factor in the resource allocation is the amount of channel state information (CSI) available at the transmitter, particularly in multiuser systems where the feedback from each user terminal must be limited. To this effect we propose two independent approaches for an efficient representation of the channel in multiuser MIMO systems. In the first approach, channel quantization is considered where the total number of feedback bits is limited. A resource allocation scheme is proposed where the available rate is split between the scheduling phase, where all users feed back a coarse CSI quantization, and the precoding phase where the selected receivers refine their CSI. The optimum splitting of the available feedback rate provides a large increase in performance and even simple heuristic splitting gives a noticeable advantage. In the second approach, we exploit a combination of instantaneous and statistical channel information. For spatially correlated Rayleigh and Ricean channels, it is shown that the CSI to large extent can be represented by the channel norm when the long-term channel statistics are known. Within a minimum mean square error (MMSE) estimation framework, feedback of a few bits of the quantized channel norm is sufficient to perform efficient resource allocation and achieve performance close to that of full CSI. [less ▲] Detailed reference viewed: 115 (0 UL)On the Maximal Diversity Order of Spatial Multiplexing With Transmit Antenna Selection; Ottersten, Björn in IEEE Transactions on Information Theory (2007), 53(11), 42734276 Detailed reference viewed: 36 (0 UL)Inter and Intra-Site Correlation of Large Scale Parameters from Macro Cellular Measurements at 1800MHz; ; Ottersten, Björn et alin EURASIP Journal on Wireless Communications and Networking (2007), 2007(3), Detailed reference viewed: 30 (1 UL)Occupant Classification Using Range ImagesDevarakota, Pandu Ranga Rao ; ; et alin IEEE Transactions on Vehicular Technology (2007), 56(2)(4), 19831993 Detailed reference viewed: 41 (0 UL)Opportunistic Beamforming and Scheduling for OFDMA Systems; ; et al in IEEE Transactions on Communications (2007), 55(5), 941952 Detailed reference viewed: 145 (0 UL)Correlation properties of large scale fading based on Indoor measurements; ; et al in IEEE Wireless Communications and Networking Conference (2007) Statistical channel models are attractive for their simplicity but sometimes lack in precision. In to improve modelling accuracy, statistical model parameters, which are dependent on the environment, are ... [more ▼] Statistical channel models are attractive for their simplicity but sometimes lack in precision. In to improve modelling accuracy, statistical model parameters, which are dependent on the environment, are extended to include spatial and temporal correlation. In outdoor scenarios these parameters are assumed constant over large areas of several wavelengths hence the name large scale parameters. This paper studies the large scale fading (LSF) and the applicability of bringing this previously used outdoor variable to the indoor case. The impacts of the model of the LSF on the outdoor system-performance have been studied and several relevant models have been proposed for outdoor cases. We present the intra-site autocorrelation as well as the inter-site cross correlation of the LSF for an indoor channel. The results are based on two separate measurement campaigns conducted at KTH, Stockholm and TUI, Ilmenau, using a single mobile station (MS) and multiple base stations (BSs) to investigate such models. We observe that the areas under which the LSF could be assumed constant are, in indoor scenarios, so small that it can be assumed independent from one local area to another. Furthermore, we find results that point towards the existence of inter-site correlation in some specific scenarios. [less ▲] Detailed reference viewed: 66 (3 UL)Joint Estimation of Mutual Coupling, Element Factor, and Phase Center in Antenna Arrays; ; et al in EURASIP Journal on Wireless Communications and Networking (2007), 2007 Detailed reference viewed: 41 (3 UL)Full Diversity Detection in MIMO Systems with a Fixed-Complexity Sphere Decoder; ; Ottersten, Björn et alin Proceedings IEEE International Conference on Acoustics, Speech, and Signal Processing (2007) Detailed reference viewed: 42 (0 UL)On Downlink Beamforming with Indefinite Shaping Constraints; ; Ottersten, Björn in IEEE Transactions on Signal Processing (2006), 54(9), 35663580 Detailed reference viewed: 69 (0 UL)System Evaluation of Optimal Downlink Beamforming with Congestion Control in Wireless Communication; ; Ottersten, Björn in IEEE Transactions on Wireless Communications (2006), 5(4), 743751 Detailed reference viewed: 31 (0 UL)Realization of a Spatially Multiplexed MIMO System; ; et al in EURASIP Journal on Applied Signal Processing (2006), 2006 Detailed reference viewed: 40 (0 UL)Interference Robustness Aspects of Space-Time Block Code-Based Transmit Diversity; Ottersten, Björn in IEEE Transactions on Signal Processing (2005), 53(4), 12991309 Detailed reference viewed: 37 (0 UL)On the Complexity of Sphere Decoding in Digital Communications; Ottersten, Björn in IEEE Transactions on Signal Processing (2005), 53 Detailed reference viewed: 51 (0 UL)Array Interpolation and DOA MSE Reduction; ; Ottersten, Björn in IEEE Transactions on Signal Processing (2005), 53(12), 44644471 Detailed reference viewed: 58 (0 UL)Minimum BER Linear Transceivers for MIMO Channels via Primal Decomposition; ; Ottersten, Björn in IEEE Transactions on Signal Processing (2005), 53(8), 28662882 Detailed reference viewed: 32 (0 UL)MIMO Channel Capacity and Modeling Issues on a Measured Indoor Radio Channel at 5.8 GHz; ; Ottersten, Björn et alin IEEE Transactions on Wireless Communications (2005), 4(3), 895903 Detailed reference viewed: 54 (0 UL) |
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