SCMA Codebook Design

By M. Taherzadeh, Hosein Nikopour, A. Bayesteh, H. Baligh. IEEE Vehicular Technology Conference, 2014

597 citations recorded by the source corpus.

Multicarrier CDMA is a multiple access scheme in which modulated QAM symbols are spread over OFDMA tones by using a generally complex spreading sequence. Effectively, a QAM symbol is repeated over multiple tones. Low density signature (LDS) is a version of CDMA with low density spreading sequences allowing us to take advantage of a near optimal message passing algorithm (MPA) receiver with practically feasible complexity. Sparse code multiple access (SCMA) is a multi-dimensional codebook-based non-orthogonal spreading technique. In SCMA, the procedure of bit to QAM symbol mapping and spreading are combined together and incoming bits are directly mapped to multi-dimensional codewords of SCMA codebook sets. Each layer has its dedicated codebook. Shaping gain of a multi-dimensional constellation is one of the main sources of the performance improvement in comparison to the simple repetition of QAM symbols in LDS. Meanwhile, like LDS, SCMA enjoys the low complexity reception techniques due to the sparsity of SCMA codewords. In this paper a systematic approach is proposed to design SCMA codebooks mainly based on the design principles of lattice constellations. Simulation results are presented to show the performance gain of SCMA compared to LDS and OFDMA.

Subfields: Artificial Intelligence, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/f1732fe25d335af43c0ff90c1b35f9b5a5c38dc5

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Citations in the corpus

6G for Vehicle-to-Everything (V2X) Communications: Enabling Technologies, Challenges, and Opportunities (2020, methodology): “There are two main types of NOMA: power-domain NOMA [69], [70] and code-domain NOMA [22], [71], such as SCMA [21], [72]–[74] and resource spread multiple access [75], in which multiple users are separated by different power levels and different codebooks/sequences, respectively.”
Massive machine-type communications in 5g: physical and MAC-layer solutions (2016, background): “Therefore, SCMA codewords are designed to be sparse [9].”
Modulation and Multiple Access for 5G Networks (2017, background): “Attributed to the multi-dimension property, the constellation in one resource block can be projected into its subspace [111].”
Cellular, Wide-Area, and Non-Terrestrial IoT: A Survey on 5G Advances and the Road Toward 6G (2021, methodology): “In spite of its moderate detection complexity, LDS suffers from performance degradation for constellation sizes larger than QPSK. SCMA is a multi-dimensional codebook NOMA scheme in which the encoder directly maps incoming data bits to SCMA codewords selected from a layer-specific codebook where eac”
A Survey on Non-Orthogonal Multiple Access for 5G Networks: Research Challenges and Future Trends (2017, background): “multiple access (SCMA) [7], [8], pattern division multiple access (PDMA) [9], [10], low density spreading (LDS) [11],”