title page
Contents
ABSTRACT 8
I. INTRODUCTION 11
II. THE OVERVIEW OF OFDMA SYSTEMS 15
2.1. Overview of OFDM and OFDMA 15
2.2. Structure of OFDMA systems 17
2.2.1. OFDMA system 17
2.2.2. Resource Allocation Schemes 20
III. PROPOSED HIERARCHICAL ARCHITECTURE MANAGEMENT 22
3.1. System Model based on a OFDMA 22
3.2. Multi-cell System Model 25
3.3. Proposed Hierarchical Architecture Management Algorithm 28
IV. COMPUTER SIMULATION 34
4.1. Performance in the Conventional OFDMA System 36
4.2. Performance in the proposed HAM scheme 42
4.2.1. Single cell OFDMA system 42
4.2.2. Multicell OFDMA system 47
V. CONCLUSION 51
VI./VII. REFERENCES 53
감사의 글 55
Table 3.1. Channel gain per each user over Rayleigh fading channel 24
Table 4.1. System parameters 35
Figure 2.1. Channel gain per each user over Rayleigh fading channel 17
Figure 2.2. Block diagram in an OFDMA Downlink system 18
Figure 3.1. Different number of resource requirement according to distance from BS 23
Figure 3.2. cochannel interferences in multi-cell system (Frequency reuse factor=1) 27
Figure 3.3. Hierarchical Architecture for the Cellular OFDMA System 29
Figure 3.4. subcarrier assignment methods in proposed scheme 32
Figure 4.1. A comparison between the uniform distribution and non-uniform distribution of the… 38
Figure 4.2. A comparison between the uniform distribution and non-uniform distribution of the… 39
Figure 4.3. The QoS outage probability for the uniform distribution in the OFDMA multicell system 40
Figure 4.4. comparison of the QoS outage probability between loads according to the distance… 41
Figure 4.5. A comparison between the uniform distribution and non-uniform distribution of the 44
Figure 4.6. A comparison between the uniform distribution and non-uniform distribution of the… 45
Figure 4.7. A comparison between without HAM and with HAM of the QoS outage probability… 46
Figure 4.8. A comparison between without HAM scheme and with HAM scheme of the QoS… 49
Figure 4.9. A comparison between macrocells underlaid the picocell and near picocell of Qos… 50