Peter A. Hoeher

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The potentials of pilot-symbol-aided channel estimation in two dimensions are explored. In order to procure this goal, the discrete shift-variant 2-D Wiener lter is derived and analyzed given an arbitrary sampling grid, an arbitrary (but possibly optimized) selection of observations, and the possibility of model mismatch. Filtering in two dimensions is(More)
For estimating the states or outputs of a Markov process, the symbol-by-symbol maximum a posteriori (MAP) algorithm is optimal. However, this algorithm, even in its recursive form, poses technical diiculties because of numerical representation problems, the necessity of non-linear functions and a high number of additions and multiplications. MAP like(More)
The use of multiple antennas for wireless communication systems has gained overwhelming interest during the last decade both in academia and industry. Multiple antennas can be utilized in order to accomplish a multiplexing gain, a diversity gain, or an antenna gain, thus enhancing the bit rate, the error performance, or the signal-to-noise-plus-interference(More)
When the same data sequence is transmitted over two independent channels, or when a data sequence is transmitted twice but independently over the same channel, the independent observations can be combined at the receiver side. From an information-theory point of view, the overall mutual information between the data sequence and the received sequences(More)
A common technique to perform lattice basis reduction is the Lenstra, Lenstra, Lovasz (LLL) algorithm. An implementation of this algorithm in real-time systems suffers from the problem of variable run-time and complexity. This correspondence proposes a modification of the LLL algorithm. The signal flow is altered to follow a deterministic structure, which(More)
In this paper, an adaptive forwarding strategy for wireless networks with relays is introduced. The strategy evaluates the error probability of a received code word at a relay based on reliability information provided by a soft-output detector. It allows to adapt to changing channel conditions by switching between the amplify and forward and the decode and(More)
Partially systematic parallel concatenated (turbo) codes of rate 1/2 are considered. These are generated from a classical rate 1/3 turbo code by puncturing both the parity bits and the systematic bits. The so-called “error-floors” of the resulting codes are lower than those of their systematic counterparts. For some puncturing patterns, even the “waterfall(More)
A novel adaptive modulation/channel coding scheme based on interleave-division multiple access (IDMA) in conjunction with reliability estimation is proposed. Unlike conventional adaptive modulation/channel coding schemes where the data rate is changed by switching between different modulation schemes and/or channel codes, in the proposed scheme the data(More)
A channel estimation scheme for Interleave-Division Multiple Access (IDMA) systems is presented. Training and data are superimposed, i.e., no bandwidth expansion compared to a system without any training is necessary. A semi-blind linear Minimum Mean Squared Error (MMSE) channel estimator is derived. Monte Carlo simulation results are presented showing that(More)