Tobias Prinz, Fabian Steiner, Thomas Wiegart and Peihong Yuan from Technische Universität München received the Heinrich Hecht award for winning the coding challenge “Wanted: Best Channel Codes for Short Underwater Messages” which was organized by the Institute of Communications in cooperation with the Technical Center for Ships and Naval Weapons, Maritime Technology and Research in Kiel.
The scenario of the challenge was an underwater acoustic sensor network where bottom-mounted sensor nodes transmit and receive short messages. These messages should be protected by an error correcting code and mapped to a given number of transmit symbols. Phase shift keying (PSK) had to be used for modulation, but the cardinality of the alphabet was chosen by the participants. The encoder and decoder had to be implemented in C++. Both processing time and memory requirements should be within given limits as sensor nodes are often battery powered and equipped with cheap hardware.
The team from TU Munich submitted a cyclic redundancy check (CRC) aided polar code with successive cancellation list decoding and QPSK modulation. Among all submitted proposals, their approach achieved the lowest block error rate for all signal-to-noise power ratios under consideration and it kept within the complexity constraints. Polar codes are a relatively new class of error correcting codes which are capacity achieving for very long block lengths. Their structure allows for low complexity encoding and decoding. As the competition showed, polar codes are also a good choice for short to medium length messages if they are combined with a CRC and if an enhanced decoder is used.
The award which is endowed with 5000 Euros is named after Karl Heinrich Hecht (1880-1961). Hecht studied Mathematics and Physics in Königsberg. In 1908, he moved to Kiel where he worked to enable underwater communication with acoustic signals. One of the main challenges was the development of powerful sound transmitters. Hecht made significant contributions to the field of hydroacoustics, especially on the problem of electroacoustic transducers. He is co-founder of the company Electroacoustic GmbH in Kiel, which still exists today.