SPbPU Researchers Proposed a New Channel Coding Method for 5G Wireless Systems

Russian Federation: a new channel coding method for the fifth generation wireless systems (5G) has been proposed by the researchers of Peter the Great St.Petersburg Polytechnic University (SPbPU).

The task of channel coding is to introduce some redundancy into the data so that it can be used to cope with errors, which occur during transmission over the wireless medium.  The simplest example of channel coding is human speech. Indeed, not every combination of sounds or letters is a valid word. This enables people to communicate even in a noisy environment. The task of engineers is to design simple and reliable channel coding techniques, which would enable gadgets, smartphones, and computers to provide new kinds of services.2-russianresea

Although the history of coding theory starts from 1948, an important breakthrough was achieved recently by the Turkish scientist Erdal Arikan, who suggested polar codes, the first class of error correcting codes, which in theory have low-complexity construction, encoding, and decoding algorithms, and achieve the Shannon limit. But for practical purposes, the performance of polar codes turned out to be not very good. Many universities in the world are working on improving polar codes. Significant progress on this issue was achieved by SPbPU researchers.

An associate professor of the Higher School of Software Engineering at SPbPU Peter Trifonov said that SPbPU researchers were able to design codes, which surpassed state-of-the-art competitors in performance and decoding simplicity. He also added that they had generalized the construction of polar codes proposed by Arikan and had obtained polar subcodes; had excluded some codewords from Arikan’s polar codes, which could be easily mixed up by the receiver, and had introduced additional restrictions on the symbols of their  codewords in order to simplify the error correction task of the decoder.

Furthermore, the researchers of Polytechnic university proposed a computationally simple decoding algorithm for polar codes and subcodes. The decoding process can be interpreted as searching for the shortest path in a labyrinth. By predicting the average number of errors at different decoding phases (in the labyrinth corridors), it was possible to significantly reduce decoding complexity. As a result, scientists of SPbPU obtained both improved performance compared to widely used low-density parity check (LDPC) codesand reduced decoding complexity.

polar codes

Improved code performance enables communication systems to operate in more challenging environments, support more users and higher data rates. Reduced decoding complexity provides longer battery life in mobile devices.

Currently, SPbPU researchers are working on implementing actual communication systems based on polar subcodes.