Title Page

Contents

Abstract 10

1. Introduction 12

2. Preliminaries 18

3. Cellular Band Sharing Scheme among Band Owners 21

3.1. System model for cellular band sharing 24

3.1.1. Cellular band sharing scenarios 24

3.1.2. Proposed learning mechanism 26

3.2. Performance evaluation of cellular band sharing 34

3.2.1. Simulation environment and performance metrics 37

3.2.2. Simulation results 42

4. Standalone Multi-Channel Selection Scheme 60

4.1. System model for cellular multi-channel shared band 63

4.1.1. Proposed multi-channel sharing system model 65

4.1.2. Neural network model for resource selection 69

4.2. Performance evaluation of multi-channel selection 72

4.2.1. Simulation environment and neural network parameters 73

4.2.2. Simulation results 79

5. Spectrum Sharing for Cell-Free Massive MIMO 96

5.1. System model for licensed sharing in cell-free massive MIMO network 99

5.1.1. Multi-operator cell-free massive MIMO network 100

5.1.2. System model and proposed sharing system 104

5.2. Performance evaluation of cell-free massive MIMO network 108

5.2.1. Simulation environment for cell-free massive MIMO network 109

5.2.2. Simulation results 111

6. Conclusions and Future Work 119

References 121

논문요약 129

Table 1. Simulation parameters 36

Table 2. Summary of the performance metrics 53

Table 3. Simulation parameters 71

Table 4. Neural network architecture 76

Table 5. Packet drop rate (PDR) for the proposed and conventional scheme 94

Figure 1. Resource allocation in conventional cellular network with dedicated frequency bands. 22

Figure 2. Resource allocation in cellular network with shared frequency bands. 23

Figure 3. Deep Neural Network design for the proposed scheme with 12 nodes in input layer, multiple hidden layers, and 3 on output layer. 27

Figure 4. Learning procedure for the proposed network. 30

Figure 5. Simulation environment 35

Figure 6. Average delay performance of proposed scheme and conventional scheme for different values of λ as simulation time increases 41

Figure 7. Comparison of resource usage of the network of proposed and conventional schemes as the simulation time increases for different values... 43

Figure 8. User perceived throughput comparison of the proposed scheme and conventional scheme as simulation time increases for different values of λ 45

Figure 9. The comparison of packet drop ratio for proposed scheme and conventional scheme as simulation time varies for different values of λ 46

Figure 10. Sum throughput performance comparison of the proposed scheme and conventional scheme as simulation time increases for different... 47

Figure 11. CDF plots of the delay for conventional and proposed schemes (λ＝0.1) 49

Figure 12. CDF plots of the delay for conventional and proposed schemes (λ＝0.667) 50

Figure 13. CDF plots of the delay for conventional and proposed schemes (λ＝1.0) 51

Figure 14. Comparison of UPT for proposed and conventional schemes when MNO 1 has λ＝0.1, MNO 2 has λ＝0.667, and MNO 3 has λ＝1.0. 55

Figure 15. Comparison of throughput for proposed and conventional schemes when MNO 1 has λ＝0.1, MNO 2 has λ＝0.667, and MNO 3 has λ＝1.0. 56

Figure 16. Comparison of different neural network structure using MLP, CNN, LSTM 58

Figure 17. Proposed system model where N number of mobile network operators (MNOs) coexist and serve to its users in the same area. 62

Figure 18. Spectrum resource usage by multiple MNOs 64

Figure 19. The logical architecture of MNO for the proposed scheme 66

Figure 20. Neural network model of the proposed scheme 68

Figure 21. Throughput of the network for different number of UEs for proposed and conventional scheme. 77

Figure 22. Throughput of the network for different number of UEs for proposed and conventional scheme. 78

Figure 23. Sum throughput of the proposed and the conventional scheme with λ＝0.8, 0.4 and 0.1 at MNOs A, B and C, respectively 80

Figure 24. Resource utilization of the proposed and the conventional scheme with λ＝0.8, 0.4 and 0.1 at MNOs A, B and C, respectively 81

Figure 25. Average delay of the proposed and the conventional scheme with λ＝0.8, 0.4 and 0.1 at MNOs A, B and C, respectively 82

Figure 26. Cumulative relative frequency of the proposed and the conventional scheme with λ＝0.8, 0.4 and 0.1 at MNOs A, B and C, respectively 83

Figure 27. Sum throughput and average underutilized resources of the proposed and the conventional scheme with λ＝0.8, 0.4 and 0.1 at MNOs A, B... 87

Figure 28. Average delay and transmission time of the proposed and the conventional scheme with λ＝0.8, 0.4 and 0.1 at MNOs A, B and C, respectively 88

Figure 29. Sum throughput and underutilized resources of the proposed and the conventional scheme with λ＝0.2 91

Figure 30. Average delay and Average transmission time of the proposed and the conventional scheme with λ＝0.2 92

Figure 31. Cell-Free massive MIMO 98

Figure 32. Multi-operator Cell-Free Massive MIMO network 102

Figure 33. Inter-operator interference scenario in multi-operator CF mMIMO spectrum sharing system 105

Figure 34. User Perceived Throughput (UPT) under asymmetric λ in CF mMIMO spectrum sharing system 112

Figure 35. Network Throughput under asymmetric λ in CF mMIMO spectrum sharing system 114

Figure 36. Average delay under asymmetric λ in CF mMIMO spectrum sharing system 115