這篇論文把研究重點放在將優化設計過後的特徵碼 (signature code) 應用在非正交之多重存取的技術上，我們將之稱為特徵編碼之多重存取 (SIGMA) 。目前的正交頻分多址 (OFDMA) 系統有著某些缺陷，比如其對於使用者連接數是受到可利用之正交性資源數量的限制。此外，OFDMA系統對於用戶連接之排程處理時間與這些控制訊號的功耗量也過高。在我們提出的特徵編碼之非正交多址技術中，每個使用者會選擇在特徵密碼本中的一組特徵碼然後所有的使用者共同分享同一塊時、頻資源以達到多址。藉由這樣的做法，我們的技術SIGMA可以達到高乘載量。在免授予的系統場景下的SIGMA技術會預先定義一塊容許所有使用者可以隨機存取的競爭區。藉由這樣的設定，網路端與使用者端就不需要藉由大量訊號控制與耗能以達到連結的過程以此達到節能與降低處理時間目標。而SIGMA技術建構了特殊設計的特徵編碼本，這樣的特徵碼具有彼此間之最小距離的最大化設計，以此能夠改善特徵碼在多址通道中的錯誤率。根據我們的設計概念，SIGMA運用了經設計後的次優化密碼本進行非正交多址。我們的模擬中說明了SIGMA在某些場景下能夠達到比SCMA與MUSA更好的錯誤率表現。

This thesis studies the design of signature code to support non-orthogonal multiple access (NOMA), called signature coded multiple access (SIGMA). In the current orthogonal frequency division multiple access (OFDMA) system, the number of connection is limited by the number of available resource element. Also, both the scheduling latency and power consumption of the OFDMA system are too high. In SIGMA, each user chooses the codeword from the signature code book, and shares the same time-frequency resources for multiple access. By doing so, SIGMA can allow high user overloading ratio. In grant free SIGMA scheme, which will predefine a contention region let users to share this region. By the predefined contention region, the network does not need to send the control signaling (SG) and the access user does not need to send the scheduling grant signal (SR). The SIGMA scheme constructs the signature code matrix with minimum distance maximization to improve the error performance in multiple access channel. According our design idea, SIGMA uses the suboptimal signature code matrix as codebook for non-orthogonal multiple access. Our results show that SIGMA can achieve better ABER performance than Sparse code multiple access (SCMA) and Multi-user shared access (MUSA).

Abstract i
Contents iii
1.Introduction 1
1.1 Foreword 1
1.2 Survey of related work 2
1.3 Research Motivation and Objective 4
1.4 Proposed Method 4
1.5 Contribution and Achievement 5
1.6 Thesis Organization 5
2.Backgrounds 7
2.1 Grant Based and Grant Free Transmission Scheme 8
2.2 Scheduling Transmission and Random Transmission 10
2.3 Non-contention Based Multiple Access 12
2.3.1 Orthogonal Frequency Division Multiple Access(OFDM) 12
2.4 Contention Based Multiple Access 13
2.4.1 Sparse Code Multiple Access(SCMA) 16
2.4.2 Multi-User Shared Access(MUSA) 18
2.5 Generalized Construction of Signature code 22
2.5.1 Sylvester-type Hadamard matrix 22
2.5.2 Kronecker product 22
2.5.3 Generalized Construction of Signature matrix 23
3.Proposed Signature-coded multiple access(SIGMA) 25
3.1 System Model 25
3.2 Signature Code Design 26
3.2.1 Signature Code Based Spreading Sequence 26
3.2.2 Minimum Distance Maximization Codebook Design 29
3.3 Receiver of Different Transmission Scheme 31
3.3.1 Receiver for Grant Based Transmission 32
3.3.2 Receiver for Grant Free Transmission 32
3.4 SIGMA Receiver for Grant Based Transmission 33
3.5 SIGMA Receiver for Grant Free Transmission 35
4.Simulation results 39
4.1 Different Signature Matrix Comparison 39
4.2 The Saturation of The Minimum Distance 42
4.3 SIGMA BER Performance Compare with MUSA 44
4.4 SIGMA BER Performance Compare with SCMA 45
4.5 Uplink Contention Based SIGMA 46
5.Conclusion 48

[1] N. Ye, W. Aihua, L. Xiangming, W. Liu, X. Hou, and Y. Hanxiao, \Rate-adaptive
multiple access (rama) for uplink grant-free transmission," Wireless Communications
and Mobile Computing, vol. 2018, Apri 2018.
[2] K. Au, L. Zhang, H. Nikopour, E. Yi, A. Bayesteh, U. Vilaipornsawai, J. Ma, and P. Zhu,
\Uplink Contention Based SCMA for 5G Radio Access," IEEE Globecom Workshops
(GC Wkshps), pp. 900{905, 2014.
[3] Y. Saito, Y. Kishiyama, A. Benjebbour, T. Nakamura, A. Li, and K. Higuchi, \Non-
Orthogonal Multiple Access (NOMA) for Cellular Future Radio Access," IEEE Vehic-
ular Technology Conference (VTC Spring), pp. 1{5, 2013.
[4] H. Kim, Y. Lim, C. Chae, and D. Hong, \Multiple access for 5g new radio:
Categorization, evaluation, and challenges," CoRR, vol. abs/1703.09042, 2017.
[Online]. Available: http://arxiv.org/abs/1703.09042
[5] H. Nikopour and H. Baligh, \Sparse Code Multiple Access," IEEE 24th Annual Interna-
tional Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC),
pp. 332{336, 2013.
[6] J. Zhang, L. Lu, Y. Sun, Y. Chen, J. Liang, J. Liu, H. Yang, S. Xing, Y. Wu, J. Ma,
I. B. F. Murias, and F. J. L. Hernando, \PoC of SCMA-Based Uplink Grant-Free
Transmission in UCNC for 5G," IEEE Journal on Selected Areas in Communications,
pp. 1353{1362, 2017.
[7] Y. Chen, A. Bayesteh, Y. Wu, S. Han, M. Taherzadeh, D. Chen, and J. Ma, \Scma: A
promising non-orthogonal multiple access technology for 5g networks," 2016 IEEE 84th
Vehicular Technology Conference (VTC-Fall), pp. 1{6, Sept 2016.
[8] Z. Yuan, G. Yu, W. Li, Y. Yuan, X. Wang, and J. Xu, \Multi-User Shared Access for
Internet of Things," IEEE Vehicular Technology Conference (VTC Spring), pp. 1{5,
2016.
[9] L. Dai, B. Wang, Y. Yuan, S. Han, C. lin I, and Z. Wang, \Non-Orthogonal Multiple
Access for 5G: Solutions, Challenges, Opportunities, and Future Research Trends,"
IEEE Communications Magazine, pp. 74{81, 2015.
[10] G.Wunder, P. Jung, M. Kasparick, T. Wild, F. Schaich, Y. Chen, S. T. Brink, I. Gaspar,
N. Michailow, A. Festag, L. Mendes, N. Cassiau, D. Ktenas, M. Dryjanski, S. Pietrzyk,
B. Eged, P. Vago, and F. Wiedmann, \5gnow: non-orthogonal, asynchronous waveforms
for future mobile applications," IEEE Communications Magazine, vol. 52, no. 2, pp. 97{
105, February 2014.
[11] J. G. Andrews, S. Buzzi, W. Choi, S. V. Hanly, A. Lozano, A. C. K. Soong, and J. C.
Zhang, \What Will 5G Be?" IEEE Journal on Selected Areas in Communications, pp.
1065{1082, 2014.
[12] L. Tian, C. Yan, W. Li, Z. Yuan, W. Cao, and Y. Yuan, \On uplink non-orthogonal
multiple access for 5g: opportunities and challenges," China Communications, vol. 14,
no. 12, pp. 142{152, December 2017.
[13] S. Vanka, S. Srinivasa, Z. Gong, P. Vizi, K. Stamatiou, and M. Haenggi, \Superposition
Coding Strategies: Design and Experimental Evaluation," IEEE Trans. on Wireless
Communications, vol. 11, no. 7, pp. 2628{2639, July 2012.
[14] M.Taherzadeh, H.Nikopour, A.Bayesteh, and H.Baligh, \SCMA Codebook Design,"
IEEE 80th Vehicular Technology Conference (VTC2014-Fall), pp. 1{5, 2014.
[15] Z. Yuan, C. Yan, Y. Yuan, and W. Li, \Blind multiple user detection for grant-free musa
without reference signal," 2017 IEEE 86th Vehicular Technology Conference (VTC-
Fall), pp. 1{5, Sept 2017.
[16] D. Lin, G. Charbit, and I.-K. Fu, \Uplink Contention Based Multiple Access for 5G
Cellular IoT," IEEE Vehicular Technology Conference, pp. 1{5, 2015.
[17] A. Bayesteh, E. Yi, H. Nikopour, and H. Baligh, \Blind Detection of SCMA for Uplink
Grant-Free Multiple-Access," International Symposium on Wireless Communications
Systems (ISWCS), pp. 853{857, 2014.
[18] S. Lu, J. Cheng, W. Hou, and Y.Watanabe, \Generalized construction of signature code
for multiple-access adder channel," 2013 IEEE International Symposium on Information
Theory, pp. 1655{1659, July 2013.
[19] S. Lu, W. Hou, and J. Cheng, \A family of (k+1) -ary signature codes for noisy multipleaccess
adder channel," IEEE Transactions on Information Theory, vol. 61, no. 11, pp.
5848{5853, Nov 2015.
[20] W. H. Mow, \Recursive constructions of detecting matrices for multiuser coding: A
unifying approach," IEEE Transactions on Information Theory, vol. 55, no. 1, pp. 93{
98, Jan 2009.
[21] D. Jevtic, \On families of sets of integral vectors whose representatives form sum-distinct
sets," SIAM Journal on Discrete Mathematics, vol. 8, no. 4, pp. 652{660, Nov 1995.
[22] D. B. Jevtic, \Disjoint uniquely decodable codebooks for noiseless synchronized
multiple-access adder channels generated by integer sets," IEEE Transactions on Infor-
mation Theory, vol. 38, no. 3, pp. 1142{1146, May 1992.
[23] F. J. MacWilliams and N. J. A. Sloane, The theory of error correcting codes. Amsterdam,
The Netherlands:North-Holland, 1977.
[24] Y. Wang, S. Zhou, L. Xiao, X. Zhang, and J. Lian, \Sparse Bayesian Learning Based
User Detection and Channel Estimation for SCMA Uplink Systems," International Con-
ference on Wireless Communications & Signal Processing (WCSP), pp. 1{5, 2015.
[25] B. Lindstrom, \Determining subsets by unramied experiments," A Survey of statistical
Design and Linear Models, 1975.
[26] D. G. Cantor and W. H. Mills, \Determination of a subsets from certain combinatorial
properties," Can. J. Math, vol. 18, pp. 42{48, Jan 1966.
[27] S. S. Martirosyan and G. G. Khachatryan, \Construction of signature codes and the
coin weighing problem,," Problem Inf. Trans, vol. 25, pp. 334{335, Oct./Dec. 1989.