Multilevel High-Rate Coding With Twofold Concatenation for IoTs in Wireless Mesh Networks

• Main Authors: Shang-Chih Ma, Mohammad Alkhaleefah, Yang-Lang Chang, Lena Chang, Bormin Huang
• Format: Article
• Language: English
• Published: IEEE 2020-01-01
• Series: IEEE Access
• Subjects: Channel coding; Internet of Things; Reed-Solomon codes; space-time block codes; wireless network
• Online Access: https://ieeexplore.ieee.org/document/9110606/

Recent studies have shown that wireless mesh networks (WMNs) can be cheap, reliable, and efficient solutions for Internet of Things (IoTs) applications and connected devices. However, the increase in the size of the WMNs could lead to a degradation in performance. This makes the network vulnerable to high error rates over noisy and fading channels. This has increased the demand for more efficient channel coding schemes that can provide reliability, high data rate, high coding gain, energy efficiency, and minimum decoding complexity especially for low-cost and special purpose WMNs. In this research, an original multilevel coding with twofold concatenation scheme is designed based on high-rate space-time block codes (HRSTBCs) to cope with this increasing demand, particularly in MIMO-based WMNs. First, a multilevel coding scheme is implemented by correlating HRSTBCs with the uniquely constructed set-partitioning of the transmission matrix, based on the coding gain distance (CGD) criterion. This generates a new scheme, namely multilevel high-rate space-time block code (MHRSTBC), to provide a high transmission rate. Second, a twofold concatenation coding scheme is introduced by concatenating Reed-Solomon (RS) code, has been used for its energy efficiency and optimality in the mobile environment, with the inner code of the associated MHRSTBC. This has formed a new scheme that reaches the maximum coding gains, called the Reed-Solomon multilevel high-rate space-time block code (RS-MHRSTBC). The efficiency of the RS-MHRSTBC is verified by a computer simulation over a Rayleigh flat-fading and additive white Gaussian noise (AWGN) channel. The RS-MHRSTBC is compared with the classical schemes of Alamouti STBC and Multilevel STBC over uncoded QPSK, and the RS-MHRSTBC shows significant high coding gains reached of 47.79 dB, while Alamouti STBC and Multilevel STBC reached 38.12 dB and 44.30 dB at a BER of 10^-6 respectively. RS-MHRSTBC also shows a reasonable decoding complexity while maintaining full transmission diversity at spectral efficiency of 2 bits/s/Hz.