未來行動裝置將會大量增長且趨向多樣化，因此佈建新空中介面（New Radio, NR）勢在必行。新空中介面制定了參數集（Numerology），定義了不同子載波（Subcarrier Spacing, SCS）的資源塊（Resource Block, RB）來滿足行動裝置多樣的需求。此外新空中介面提供非正交多址接入（Non-Orthogonal Multiple Access, NOMA）來疊加訊號以提高頻譜效率。當長期演進技術（Long Term Evolution, LTE）和新空中介面共存在行動網路中時，雙基地台連線(Dual Connectivity, DC)使用戶能夠同時訪問兩個基地台 (Base Station, BS)，以聚合無線電資源，最終支持用戶的流量需求。此外，為了保持基地台的大覆蓋率，長期演進技術與新空中介面共用了具有低路徑損耗的特性的低頻譜。然而，當兩個用戶復用一個頻道時，載波之間會產生交互參數集干擾 (Inter-Numerology Interference, INI)的問題。本研究在4G與5G共存的情境下，將雙連線結合非正交多址接入與混合參數集系統，以提供更高的頻譜效率。5G基地台（Next Generation NodeB, gNB）透過混合參數集滿足不同用戶的傳輸需求，並通過非正交多址接入增加基地台容量。而4G基地台（E-UTRAN NodeB, eNB）部分覆蓋了5G基地台，並為雙連線的用戶提供服務。同時，兩個基地台共享部分頻譜。本研究定義了一個資源分配問題，為用戶選擇連線的基地台，並以最大化總吞吐量為目標分配資源塊給用戶。此資源分配問題被證明為非多項式複雜度（Non-Deterministic Polynomial-Time Hardness, NP-hard）。為了獲得近似解，本研究提出了資源疊用形成演算法（Zone Pile Formation, ZPF）與雙連線資源切割演算法（DC Slicing），以降低交互參數集干擾與跨基地台索取資源。數據結果表明，所提出的演算法在吞吐量和干擾方面優於現有的其他方法。

New Radio (NR) is capable of serving a diverse and massive amount of users through the numerologies with different Subcarrier Spacing (SCS). Moreover, to improve spectral efficiency, NR proposes Non-Orthogonal Multiple Access (NOMA) that superimposes signals. The coexistence of Long Term Evolution (LTE) and NR requires Dual Connectivity (DC), which enables users to access both Base Stations (BSs) simultaneously, to aggregate the radio resources and support the traffic requirements. Besides, to extend the coverage of BSs, the spectrum with low path loss is shared by LTE and NR. An issue to be solved is the unalignment of SCS, when two users reuse a channel, which causes Inter-Numerology Interference (INI). In this thesis, we introduce DC into a NOMA-based mixed numerology system to provide a high-loading spectrum. The Next Generation NodeB (gNB) may fulfill diverse users with unique numerology and increase BS capacity by NOMA, and the E-UTRAN NodeB (eNB) covers the gNB and serves the DC users. Meanwhile, the two BSs shares part of the spectrum. A resource allocation algorithm is formulated to associate the users to the BSs and allocates the Resource Blocks (RBs) to users aiming to maximize total throughput, which we prove to be an NP-hard problem. To obtain an optimal solution, the RBs are managed by Zone Pile Formation (ZPF) to decrease the INI, and by DC Slicing for BS association. Numerical results show that the proposed algorithm outperforms state-of-the-art algorithms regarding throughput and interference.

1 Introduction ............................................... 1
2 Related Works .............................................. 6
2.1 Resource Allocation of Numerology and NOMA in 5G ......... 6
2.2 Resource Allocation in DC ................................ 7
2.3 Resource Allocation in Sharing Spectrum .................. 7
3 Network Model .............................................. 9
3.1 Resource Grid ............................................ 9
3.2 System Model ............................................. 11
3.3 Channel Model ............................................ 13
4 Problem Formulation ........................................ 15
5 Algorithm .................................................. 19
5.1 Algorithm Description .................................... 20
5.2 Approximation Ratio ...................................... 31
5.3 Complexity Analysis ...................................... 35
6 Simulation ................................................. 37
6.1 Simulation Settings....................................... 37
6.2 Simulation Results ....................................... 38
7 Conclusions ................................................ 44

[1] S. Parkvall, E. Dahlman, A. Furuskar, and M. Frenne, “NR: The new 5G radio access technology,” IEEE Commun. Standards Mag., vol. 1, no. 4, pp. 24–30, 2017.
[2] G. M. D. T. Forecast, “Cisco visual networking index: Global mobile data traffic forecast update, 2018–2023,” Cisco, White Paper, Feb. 2020.
[3] M. Agiwal, H. Kwon, S. Park, and H. Jin, “A survey on 4G-5G dual connectivity: Road to 5G implementation,” IEEE Access, vol. 9, pp. 16 193–16 210, 2021.
[4] L. Wan, Z. Guo, and X. Chen, “Enabling efficient 5G NR and 4G LTE coexistence,” IEEE Wireless Commun., vol. 26, no. 1, pp. 6–8, 2019.
[5] I. Da Silva, G. Mildh, J. Rune, P. Wallentin, J. Vikberg, P. Schliwa-Bertling, and R. Fan, “Tight integration of new 5G air interface and LTE to fulfill 5G requirements,” in Proc. IEEE 81st Veh. Technol. Conf., 2015, pp. 1–5.
[6] 3GPP, “Universal mobile telecommunications system (UMTS); LTE; 5G; NR; multi- connectivity; overall description; stage-2,” 3GPP, Technical Specification (TS) 37.34, Apr. 2021.
[7] C. Li, H. Wang, and R. Song, “Intelligent offloading for NOMA-assisted MEC via dual connectivity,” IEEE Internet of Things J., vol. 8, no. 4, pp. 2802–2813, 2021.
[8] Y. Wu, Y. He, L. P. Qian, J. Huang, and X. Shen, “Optimal resource allocations for mobile data offloading via dual-connectivity,” IEEE Trans. Mobile Comput., vol. 17, no. 10, pp. 2349–2365, 2018.
[9] Y. Shi, H. Qu, and J. Zhao, “Dual-connectivity enabled resource allocation approach with eICIC for throughput maximization in hetnets with backhaul constraint,” IEEE Wireless Commun. Lett., vol. 8, no. 4, pp. 1297–1300, 2019.
[10] Y. Arjoune and N. Kaabouch, “A comprehensive survey on spectrum sensing in cog- nitive radio networks: Recent advances, new challenges, and future research direc- tions,” Sensors, vol. 19, no. 1, 2019. [Online]. Available: https://www.mdpi.com/ 1424-8220/19/1/126.
[11] L. C. Alexandre, A. L. De Souza Filho, and A. C. Sodré, “Indoor coexistence analysis among 5G new radio, LTE-A and NB-IoT in the 700 MHz band,” IEEE Access, vol. 8, pp. 135 000–135 010, 2020.
[12] B. Liu and M. Peng, “Joint resource block-power allocation for NOMA-enabled fog radio access networks,” in Proc. IEEE Int. Conf. Commun. (ICC), 2019, pp. 1–6.
[13] S. McWade, M. F. Flanagan, L. Zhang, and A. Farhang, “Interference and rate anal- ysis of multinumerology NOMA,” in Proc. IEEE Int. Conf. Commun. (ICC), 2020, pp. 1–6.
[14] P. K. Korrai, E. Lagunas, A. Bandi, S. K. Sharma, and S. Chatzinotas, “Joint power and resource block allocation for mixed-numerology-based 5G downlink under im- perfect CSI,” IEEE Open J. Commun. Soc., vol. 1, pp. 1583–1601, 2020.
[15] J. Choi, B. Kim, K. Lee, and D. Hong, “A transceiver design for spectrum sharing in mixed numerology environments,” IEEE Trans. Wireless Commun., vol. 18, no. 5, pp. 2707–2721, 2019.
[16] M. Shafi, A. F. Molisch, P. J. Smith, T. Haustein, P. Zhu, P. De Silva, F. Tufves- son, A. Benjebbour, and G. Wunder, “5G: A tutorial overview of standards, trials, challenges, deployment, and practice,” IEEE J. Sel. Areas Commun., vol. 35, no. 6, pp. 1201–1221, 2017.
[17] 3GPP, “NR; physical channels and modulation,” 3GPP, Technical Specification (TS) 38.211, Jan. 2020.
[18] X. Zhang, L. Zhang, P. Xiao, D. Ma, J. Wei, and Y. Xin, “Mixed numerologies interference analysis and inter-numerology interference cancellation for windowed OFDM systems,” IEEE Trans. Veh. Technol., vol. 67, no. 8, pp. 7047–7061, 2018.
[19] S. McWade, M. F. Flanagan, J. Mao, L. Zhang, and A. Farhang, “Resource allocation for mixed numerology NOMA,” 2021. [Online]. Available: arXiv:2102.01005.
[20] R.-J. Wang, C.-H. Wang, G.-S. Lee, D.-N. Yang, W.-T. Chen, and J.-P. Sheu, “Re- source allocation in 5G with NOMA-based mixed numerology systems,” in Proc. IEEE Global Commun. Conf. (GLOBECOM), 2020, pp. 1–6.
[21] J. Zeng, T. Lv, R. P. Liu, X. Su, M. Peng, C. Wang, and J. Mei, “Investigation on evolving single-carrier NOMA into multi-carrier NOMA in 5G,” IEEE Access, vol. 6, pp. 48 268–48 288, 2018.
[22] Z. Ding, X. Lei, G. K. Karagiannidis, R. Schober, J. Yuan, and V. K. Bhargava, “A survey on non-orthogonal multiple access for 5G networks: Research challenges and future trends,” IEEE J. Sel. Areas Commun., vol. 35, no. 10, pp. 2181–2195, 2017.
[23] B. Liu, C. Liu, and M. Peng, “Resource allocation for energy-efficient MEC in NOMA-enabled massive IoT networks,” IEEE J. Sel. Areas Commun., vol. 39, no. 4, pp. 1015–1027, 2021.
[24] W. Ni, X. Liu, Y. Liu, H. Tian, and Y. Chen, “Resource allocation for multi-cell IRS- aided NOMA networks,” IEEE Trans. Wireless Commun., vol. 20, no. 7, pp. 4253– 4268, 2021.
[25] Y. Wu and L. P. Qian, “Energy-efficient NOMA-enabled traffic offloading via dual- connectivity in small-cell networks,” IEEE Commun. Lett., vol. 21, no. 7, pp. 1605– 1608, 2017.
[26] C. Yu, L. Yu, Y. Wu, and Y. He, “Transmit-power minimization for NOMA-enabled traffic offloading with security provisioning,” IEEE Commun. Lett., vol. 22, no. 5, pp. 986–989, 2018.
[27] Y. Tian, G. Pan, and M.-S. Alouini, “On NOMA-based mmWave communications,” IEEE Trans. Veh. Technol., vol. 69, no. 12, pp. 15 398–15 411, 2020.
[28] L. Dai, B. Wang, Y. Yuan, S. Han, I. Chih-lin, and Z. Wang, “Non-orthogonal mul- tiple access for 5G: Solutions, challenges, opportunities, and future research trends,” IEEE Commun. Mag., vol. 53, no. 9, pp. 74–81, 2015.
[29] M. Alsenwi, N. H. Tran, M. Bennis, S. R. Pandey, A. K. Bairagi, and C. S. Hong, “Intelligent resource slicing for eMBB and URLLC coexistence in 5G and beyond: A deep reinforcement learning based approach,” IEEE Trans. Wireless Commun., vol. 20, no. 7, pp. 4585–4600, 2021.
[30] L. Marijanovic, S. Schwarz, and M. Rupp, “A novel optimization method for re- source allocation based on mixed numerology,” in Proc. IEEE Int. Conf. Commun. (ICC), 2019, pp. 1–6.
[31] M. Yi, Y. Zhang, X. Wang, C. Xu, and X. Ma, “Deep reinforcement learning for user association in heterogeneous networks with dual connectivity,” in Proc. IEEE Wireless Commun. Netw. Conf. (WCNC), 2021, pp. 1–5.
[32] P. K. Taksande, P. Chaporkar, P. Jha, and A. Karandikar, “Proportional fairness through dual connectivity in heterogeneous networks,” in Proc. IEEE Wireless Com- mun. Netw. Conf. (WCNC), 2020, pp. 1–6.
[33] G. S. Park and H. Song, “Video quality-aware traffic offloading system for video streaming services over 5G networks with dual connectivity,” IEEE Trans. Veh. Tech- nol., vol. 68, no. 6, pp. 5928–5943, 2019.
[34] W. Yin, L. Xu, P. Wang, Y. Wang, Y. Yang, and T. Chai, “Joint device assignment and power allocation in multihoming heterogeneous multicarrier NOMA networks,” IEEE Syst. J., pp. 1–12, 2020.
[35] Y. Huang, M. Zhang, and Y. Shang, “A user access method based on game theory in UDN considering PLS and NOMA,” in Proc. IEEE 93rd Veh. Technol. Conf., 2021, pp. 1–5.
[36] L. Wan, Z. Guo, Y. Wu, W. Bi, J. Yuan, M. Elkashlan, and L. Hanzo, “4G/5G spec- trum sharing: Efficient 5G deployment to serve enhanced mobile broadband and in- ternet of things applications,” IEEE Veh. Technol. Mag., vol. 13, no. 4, pp. 28–39, 2018.
[37] 3GPP, “LTE; evolved universal terrestrial radio access (E-UTRA); physical channels and modulation,” 3GPP, Technical Specification (TS) 36.211, Apr. 2020.
[38] L. You, Q. Liao, N. Pappas, and D. Yuan, “Resource optimization with flexible nu- merology and frame structure for heterogeneous services,” IEEE Commun. Lett., vol. 22, no. 12, pp. 2579–2582, 2018.
[39] A. Khalili, E. M. Monfard, S. Zargari, M. R. Javan, N. Mokari, and E. A. Jor- swieck, “Resource management for transmit power minimization in UAV-assisted RIS hetnets supported by dual connectivity,” 2021. [Online]. Available: arXiv : 2106.13174.
[40] P.-J. Hsieh, W.-S. Lin, K.-H. Lin, and H.-Y. Wei, “Dual-connectivity prevenient handover scheme in control/user-plane split networks,” IEEE Trans. Veh. Technol., vol. 67, no. 4, pp. 3545–3560, 2018.
[41] N.-T. Le, L.-N. Tran, Q.-D. Vu, and D. Jayalath, “Energy-efficient resource alloca- tion for OFDMA heterogeneous networks,” IEEE Trans. Commun., vol. 67, no. 10, pp. 7043–7057, 2019.
[42] D. T. Ngo, S. Khakurel, and T. Le-Ngoc, “Joint subchannel assignment and power allocation for OFDMA femtocell networks,” IEEE Trans. Wireless Commun., vol. 13, no. 1, pp. 342–355, 2013.

[43] K. Arshad and S. Rostami, “Resource allocation for multi-carrier cellular networks,” in Proc. IEEE Wireless Commun. Netw. Conf. (WCNC), 2018, pp. 1–6.
[44] L. Dai, B. Wang, Z. Ding, Z. Wang, S. Chen, and L. Hanzo, “A survey of non- orthogonal multiple access for 5G,” IEEE Commun. Surv. Tutorials, vol. 20, no. 3, pp. 2294–2323, 2018.
[45] 3GPP, “LTE; evolved universal terrestrial radio access (E-UTRA); physical layer procedures,” 3GPP, Technical Specification (TS) 36.213, May 2021.
[46] ——, “5G; NR; physical layer procedures for data,” 3GPP, Technical Specification (TS) 38.214, Apr. 2021.
[47] J. Rao and S. Vrzic, “Packet duplication for URLLC in 5G dual connectivity archi- tecture,” in Proc. IEEE Wireless Commun. Netw. Conf. (WCNC), 2018, pp. 1–6.
[48] T. T. Nguyen, V. N. Ha, and L. B. Le, “Wireless scheduling for heterogeneous services with mixed numerology in 5G wireless networks,” IEEE Commun. Lett., vol. 24, no. 2, pp. 410–413, 2020.
[49] Q. Han, B. Yang, C. Chen, and X. Guan, “Matching-based cell selection for pro- portional fair throughput boosting via dual-connectivity,” in Proc. IEEE Wireless Commun. Netw. Conf. (WCNC), 2017, pp. 1–6.
[50] 3GPP, “5G; NR; NR and NG-RAN overall description; stage-2,” 3GPP, Technical Specification (TS) 38.300, Apr. 2021.
[51] ——, “5G; study on channel model for frequencies from 0.5 to 100 GHz,” 3GPP, Technical Report (TR) 38.901, Nov. 2020.
[52] N. Jinaporn, S. Armour, and A. Doufexi, “Performance evaluation on resource allo- cation with carrier aggregation in LTE cellular networks,” in Proc. IEEE 90th Veh. Technol. Conf., 2019, pp. 1–5.
[53] Z. Zhao, J. Shi, Z. Li, L. Yang, Y. Zhao, and W. Liang, “Matching theory assisted resource allocation in millimeter wave ultra dense small cell networks,” in Proc. IEEE Int. Conf. Commun. (ICC), 2019, pp. 1–6.
[54] 3GPP, “LTE; evolved universal terrestrial radio access (E-UTRA); user equipment (UE) radio transmission and reception,” 3GPP, Technical Specification (TS) 36.101, May 2021.
[55] ——, “5G; NR; user equipment (UE) radio transmission and reception; part 1: Range 1 standalone,” 3GPP, Technical Specification (TS) 38.101-1, May 2021.
[56] L. Du, N. Zheng, H. Zhou, J. Chen, T. Yu, X. Liu, Y. Liu, Z. Zhao, X. Qian, J. Chi, et al., “C/U split multi-connectivity in the next generation new radio system,” in Proc. IEEE 85th Veh. Technol. Conf., 2017, pp. 1–5.
[57] C. She, Z. Chen, C. Yang, T. Q. Quek, Y. Li, and B. Vucetic, “Improving network availability of ultra-reliable and low-latency communications with multi-connectivity,” IEEE Trans. Commun., vol. 66, no. 11, pp. 5482–5496, 2018.
[58] 3GPP, “Evolved universal terrestrial radio access (E-UTRA); radio frequency (RF) requirements for LTE pico node B,” 3GPP, Technical Report (TR) 36.931, Jan. 2016.
[59] ——, “5G; NR; user equipment (UE) radio access capabilities,” 3GPP, Technical Specification (TS) 38.306, Apr. 2021.
[60] G. Simsek, H. Alemdar, and E. Onur, “Multi-connectivity enabled user association,” in Proc. IEEE 30th Annu. Int. Symp. Pers., Indoor, Mobile Radio Commun. (PIMRC), 2019, pp. 1–6.