Iterative Channel Estimation with Polar Codes for Short Block Transmission

This paper proposes a novel iterative channel estimation scheme incorporating polar codes for short block transmission application. To satisfy the requirement of ultra-reliable and low-latency communications (URLLC) in the fifth generation mobile communication (5G), transceiver should realize reduced processing delay as well as bit error rate. Polar codes have been emerged as one of the most promising forward error correction (FEC) codes for mobile communications. Although it can maximize the channel capacity exploiting a phenomenon called channel polarization with a reasonable complexity, requires a large bit sequences due to its nature as the block codes. In order to reduce the processing delay for awaiting signal reception worth of coded block, its length should be shorter as much as possible in compensation for degradation of error correction performance. Meanwhile Iterative channel estimation (ICE) is known as the effective channel estimation method using decided data estimates. It can track the channel time variation and channel estimation accuracy can be improved by iterative decision feedback with the aid of error correction function. Fully exploiting the good match of polar codes and ICE, error correction performance can be maintained even though the block size is shortened. We present an efficient ICE scheme based on polar codes with introducing time-domain channel interpolation and extrapolation. The proposed scheme can contribute to reduce computation amount and thus ensure low latency. Computer simulation results verify its improved BER performance even under the fast fading environment.