Gottfried Schnabl

Soft-decision decoding of Reed-Muller codes as generalized multiple concatenated codes

Constructs Reed-Muller codes by generalized multiple concatenation of binary block codes of length 2. As a consequence of this construction, a new decoding procedure is derived that uses soft-decision information. The algorithm is designed for low decoding complexity and is applicable to all Reed-Muller codes. It gives better decoding performance than soft-decision bounded-distance decoding. Its decoding complexity is much lower than that of maximum-likelihood trellis decoding of Reed-Muller codes, especially for long codes. >

Hybrid beamforming: reduced eigen beamforming on beam signals

A hybrid beamforming technique for multiple antenna receivers is introduced. It is a combination of a simple fixed beam method and the adaptive eigen beamforming algorithm. This two-stage solution allows for a user-specific scalable trade-off between performance and complexity, depending on the interference scenario. Furthermore, the dimensions of the eigen beamforming stage can be reduced with only slight performance degradation. The hybrid scheme is compared with the stand-alone algorithms in different two-user scenarios under ideal as well as under more realistic assumptions. It is shown, that in many scenarios the fixed beamforming stage is sufficient. In more severe interference scenarios, the hybrid techniques approach the performance of the eigen beamformer with less complexity.

Coded Modulation with Generalized Multiple Concatenation of Block Codes

Block coded modulation schemes can be obtained by generalized concatenation of the modulation and block codes of length N. The modulation is considered as a code in the euclidean space IR2. One obtains a concatenated code in the euclidean space IR2N using binary block codes. In this paper the obtained code is taken as an inner code, which is concatenated with block codes once again. The advantage of this multiple concatenation compared to single concatenation is the use of very short (easy to decode) outer codes such as repetition codes and even weight codes.