Network coding schemes with efficient LDPC coded MIMO–NOMA in two-way relay networks

• Main Authors: Takashi Kamada1,2 ·, Mary Lyn Johanis2 ·, Ng, Shean Yeaw, Phan, Chin Soon, Monica Suleiman, Charles Santhanaraju Vairappan
• Format: Article
• Language: English; English
• Published: 2020
• Subjects: QH301-705.5 Biology (General)
• Online Access: https://eprints.ums.edu.my/id/eprint/25640/1/Network%20coding%20schemes%20with%20efficient%20LDPC%20coded%20MIMO%E2%80%93NOMA%20in%20two-way%20relay%20networks.pdf; https://eprints.ums.edu.my/id/eprint/25640/2/Network%20coding%20schemes%20with%20efficient%20LDPC%20coded%20MIMO%E2%80%93NOMA%20in%20two-way%20relay%20networks1.pdf; https://eprints.ums.edu.my/id/eprint/25640/; https://doi.org/10.1007/s13659-020-00232-6
• Institution: Universiti Malaysia Sabah

The combination of non-orthogonal multiple access (NOMA) and multi-input multi-output (MIMO) approaches has been considered as assuring multiple access for the fifth generation technology. In this study, the performance of a 2 × 2 MIMO- NOMA system with low-density parity check (LDPC) codes is investigated. Redundancy with randomly interleaved differential encoding (R-RIDE) is proposed and applied to LDPC encoded messages by two users. LDPC decoding is done using the sum-product algorithm (SPA), which has two types of decoding methods, hard-decision and soft-decision. For hard-decision, bit-flipping decoder is used and for soft-decision, probability domain, log-domain, and simplified log-domain decoders are used. Bit error rate (BER) versus signal-to-noise ratio (SNR) in (dB) and average mutual information (AMI) in (bps/Hz) versus SNR (dB) are evaluated to compare the performance of the proposed and conventional LDPC schemes in NOMA and MIMO-NOMA systems. Simulation results show that both AMI and BER of the proposed LDPC-R-RIDE in MIMO-NOMA system greatly outperforms conventional LDPC coded schemes in NOMA and MIMO-NOMA systems. Moreover, the proposed R-RIDE-LDPC in MIMO-NOMA system outperforms the proposed scheme in the NOMA system. From the simulation results, LDPC-R-RIDE with simplified log-domain decoder has the best AMI result and BER performance compared with other decoding methods.