Michal Simko

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In this paper, hardware implementation aspects of the channel estimator in 3GPP LTE terminals are investigated. A channel estimation ASIC, which handles the real-time channel estimation, is presented. Compared to traditional correlatorbased channel estimators, the channel estimator presented boosts the throughput at feasible silicon cost by adopting a(More)
Nowadays, most wireless communication systems employ coherent demodulation on the receiver side. Under this circumstance, part of the available transmission resource is reserved and utilized for channel estimation, referred to as pilot symbols. In recent standards, for example long-term evolution (LTE), a certain adjustment is allowed for the power radiated(More)
This paper presents an SINR prediction model for LTE systems with the aim of improving the accuracy of physical layer models used for higher-than-physical-level simulations. This physical layer SINR abstraction for zero-forcing receivers takes channel estimation errors into account. It allows for the calculation of the post-equalization receive SINR of an(More)
In this article, we introduce MATLAB-based link and system level simulation environments for UMTS Long-Term Evolution (LTE). The source codes of both simulators are available under an academic non-commercial use license, allowing researchers full access to standard-compliant simulation environments. Owing to the open source availability, the simulators(More)
Cellular networks are an essential part of todays communication infrastructure. The ever-increasing demand for higher data-rates calls for a close cooperation between researchers and industry/standardization experts which hardly exists in practice. In this article we give an overview about our efforts in trying to bridge this gap. Our research group(More)
In scenarios with time-varying channels such as intelligent traffic systems or high speed trains, the orthogonality between subcarriers in orthogonal frequency division multiplexing (OFDM) is destroyed leading to inter-carrier interference (ICI). In the literature, ICI equalization algorithms have been proposed; however, they assume perfect channel(More)
The UMTS Long Term Evolution (LTE) allows the pilot symbol power to be adjusted with respect to that of the data symbols. Such power increase at the pilot symbols results in a more accurate channel estimate, but in turn reduces the amount of power available for the data transmission. In this paper, we derive optimal pilot symbol power allocation based on(More)
In this paper, we present an Approximate Linear Minimum Mean Square Error (ALMMSE) fast fading channel estimator for Orthogonal Frequency Division Multiplexing (OFDM). The ALMMSE channel estimator utilizes the knowledge of the structure of the autocorrelation matrix given by the Kronecker product between the time correlation matrix and the frequency(More)
In this paper, we develop several increasingly tight and restrictive performance bounds for OFDM based MIMO wireless communication systems. Starting with channel capacity as the ultimate upper bound on the throughput, step by step we develop tighter bounds on the practically achievable throughput by incorporating typical design constraints. The presented(More)