Forward error-correction techniques in LTE systems

Abstract

Error-correction codes (ECCs) are one of the most important issues in digital communication systems to enhance data reliability via noisy channels. In wireless transmission channels, the transmitted data is exposed to several factors (for instance, multipath fading environments, atmospheric variations, and electromagnetic interferences), which makes the performance of any communication system unacceptable. In this paper, different forward error-correction (FEC) codes (including turbo, LDPC, convolutional, RS, polar, and BCH), especially those that are already proposed for LTE systems in terms of BER performance and decoding complexity, were discussed to show the advantages and disadvantages of each. While the trade-off between improving system performance and decoding complexity has been discussed, achieving balance between decreasing BER and maintaining the decoding complexity at acceptable levels is important. Where, this comparison is a necessary to figure out the optimal ECCs for LTE systems in terms of capability of error correction and low decoding complexity. The comparison shows that, although error correction capability is high for LDPC codes, the phenomenon of error floor restricts using them in applications that need to lower error rates. By contrast, in finite-length regimes, the performance of polar codes is critical unlike other coding techniques. Among different forward error-correction codes, RS and BCH codes were the best with LTE systems because of their highly improved system performance and low decoding complexity unlike convolutional and turbo codes. However, RS codes outperform BCH codes in terms of BER performance because of their high capability in correcting burst errors.