Ralf Bendlin

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Heterogeneous cellular networks (HetNets)—conventional macro base stations overlaid with low-power nodes—are being deployed for reasons of improved spectral efficiency, economy, and scalable network expansion. To optimally realize the benefits of HetNets, it is crucial to factor deployment aspects such as cell association, transmission power,(More)
Both fast scheduling and spatial signal processing have proven to be capacity-increasing methods in wireless communication systems. However, when applied in the downlink of a cellular network, the combination of both leads to nonstationary intercell interference. If the base stations do not cooperate, either they have to encode the data very conservatively(More)
Multi-cell coordination is a technique for interference mitigation in cellular systems. For joint-transmission (JT), the received signal power is boosted by diversity combining of signals from multiple transmission points. This however results in reduced frequency-reuse ratio and cell-splitting order, which may subsequently degrade the network-level(More)
We consider the downlink of a wireless cellular network where the base stations are equipped with multiple antennas and operate in the same frequency band. Since scheduling changes the spatial transmit signal processing with each time slot, information from neighboring base stations is required for data encoding. This can, in theory, be accomplished by a(More)
We consider the downlink of a cellular multiple input single output (MISO) system with multiple users per cell. Fast scheduling and spatial signal processing at the base stations result in unpredictable non-stationary intercell interference when the base stations do not cooperate. We show how the per cell sum-rate can be increased when Kalman filters are(More)
To improve link reliability and data throughput in wireless communications, it is well known that we can exploit both the spatial and the temporal domain by precoding and scheduling, respectively. For cellular networks, however, most of these gains can only be obtained when frequency resources are carefully allocated to the different base stations as(More)
We consider a multi-user multiple-input single-output (MU-MISO) scenario, where the decentralized users are served by a centralized transmitter with multiple channel inputs via frequency selective vector channels. For this broadcast setup, we jointly design the transmitter and receivers based on a minimum sum mean square error (MSE) criterion. Contrary to(More)
The global popularity and rapid proliferation of smartphones and other types of mobile devices has greatly expanded the amount of mobile data traffic throughout the wireless cellular network. Research studies from Mobile Experts, Cisco VNI and Ericsson have shown that global mobile traffic reached 1,000 petabytes per month and is projected to grow(More)
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