Rikke Apelfrojd

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Channel state information at transmitters is important for advanced transmission schemes. However, feedback and transmission control delays of multiple milliseconds in LTE systems result in severe outdating of this information at vehicular velocities. Channel prediction based on extrapolation of the short-term fading is inadequate in LTE systems at(More)
Coordinated multi-point (CoMP) transmission is considered as an efficient technique to improve cell-edge performance as well as system spectrum efficiency. In CoMPenabled systems, a cluster of coordinated base stations (BSs) are typically assumed to be connected to a control unit (CU) via backhaul links, and the provided performance gain relies heavily on(More)
Coordinated multipoint (CoMP) transmission provides high theoretic gains in spectral efficiency with coherent joint transmission (JT) to multiple users. However, this requires accurate channel state information at the transmitter (CSIT) and also user groups with spatially compatible users. The aim of this paper is to use measured channels to investigate if(More)
The data traffic volumes are constantly increasing in cellular networks. Furthermore, a larger part of the traffic is generated by applications that require high data rates. Techniques including Coordinated Multipoint transmission (CoMP) can increase the data rates, but at the cost of a high overhead. The overhead can be reduced if only a subset of the(More)
Coordinated Multipoint (CoMP) transmission provides high theoretic gains in spectral efficiency, in particular with coherent linear Joint Transmission (JT) to multiple users. However, this requires high backhaul capacity. If the backhaul requirement cannot be met by the system, then CoMP gains decrease as the linear precoder matrix must be adjusted to(More)
Channel state information at transmitters is important for advanced transmission schemes. However, feedback and transmission control delays of multiple milliseconds in LTE systems result in severe outdating of this information at vehicular velocities. Channel prediction based on extrapolation of the short-term fading is inadequate in LTE systems at(More)
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