正交分頻多重存取系統以效用函數為基礎之資源配置與功率控制

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研究生：	陳曉琳 Hsiao-Lin Chen
論文名稱：	正交分頻多重存取系統以效用函數為基礎之資源配置與功率控制 Utility-based Resource Allocation and Power Control on OFDMA Communications
指導教授：	林嘉慶 Jia-Chin Lin
口試委員:
學位類別：	碩士 Master
系所名稱：	資訊電機學院 - 通訊工程學系 Department of Communication Engineering
畢業學年度：	97
語文別：	英文
論文頁數：	73
中文關鍵詞：	功率控制、正交分頻多工、正交分頻多重存取、資源配置、動態子載波分配
外文關鍵詞：	utility function, OFDM, resource allocation, OFDMA, subcarrier allocation
相關次數：	點閱：7 下載：0
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查詢本校圖書館目錄查詢臺灣博碩士論文知識加值系統勘誤回報

隨著各種無線通訊服務的提供，使用者對於無線傳輸的需求及品質的要求日益提升。
本篇論文提出了轉換子載波配置演算法（Shift Subcarrier Allocation, SSA），為正交分頻
多重存取系統於下行鏈結，以效用函數為基礎（Utility-based）之資源分配與功率控制的
演算法，藉由效用函數並對子載波進行二維的排序及搜尋，將適宜的子載波分配與通道
增益較佳的使用者，避免使用通道品質較差的子載波，並與現有之演算法相比較。
經由模擬結果得知，建設性初始化分配演算法(Constructive initial allocation)雖有較
佳的效能表現，但需要大量的置換運算時間，轉換子載波配置演算法（SSA）不需要大
量的置換運算時間即可以使效能得到顯著的改善；在本學位論文中，我們使用轉換子載
波配置演算法(SSA)來達到增加輸出率和降低符號、位元錯誤率及傳輸功率的目的。根
據模擬結果得知，當系統以效用函數為基礎結合轉換子載波配置演算法(SSA)後，可以
確保無線傳輸的品質，使輸出率得到顯著的提升，並且降低傳輸功率。

With increasing usage of wireless communications, the requirement of faster transmission rates
has also increased rapidly. This thesis is concerned with the problem of dynamic resource allocation
and power control. Given the availability of multi-path channels and the transmission rate
requirements of various wireless transmission users, it is necessary to consider a joint channel,
power and rate assignment scheme that satisfies multimedia multi-rate requirements while using
minimal total power.
In this thesis, a dynamic subcarrier allocation algorithm, called the shift subcarrier allocation
algorithm (SSA), is proposed. The SSA algorithm is designed to avoid allocating much power onto
deeply faded bands, reducing transmission power and insuring fairness for each user. To support the
diverse quality of services (QoS) requirements of multimedia traffic, the SSA was designed for
applying onto OFDMA downlink systems. The goals of SSA are QoS satisfaction, throughput
maximization and power sum minimization while satisfying total power or energy constraints.

摘 要................................................................................................................................................i
ABSTRACT....................................................................................................................................ii
Acknowledgments..........................................................................................................................iii
Contents .........................................................................................................................................iv
List of Figures ...............................................................................................................................vii
List of Tables ..................................................................................................................................x
Chapter 1
Introduction.....................................................................................................................................1
1.1 Motivation and Background ..................................................................................................1
1.2 Related Works........................................................................................................................2
1.3 Problem Description and Goal...............................................................................................2
1.4 Organization of the Thesis .....................................................................................................3
Chapter 2
Introduction to OFDMA System .....................................................................................................4
2.1 OFDM Transceiving System .................................................................................................4
2.1.1 Cyclic Prefix ...................................................................................................................8
2.1.2 Discrete-Time Equivalent System Model.......................................................................9
2.2 OFDMA Transceiving System.............................................................................................10
2.3 Channels in Mobile Communication ...................................................................................12
2.3.1 Jakes’ Fading Channel Model.......................................................................................13
2.3.2 IMT-2000 Channel Model ............................................................................................16
2.4 Introduction to WiMAX ......................................................................................................19
Chapter 3
Utility Function in Resource allocation .........................................................................................21
3.1 VoIP Utility Function...........................................................................................................21
3.2 IPTV Utility Function ..........................................................................................................23
3.3 HTTP Utility Function .........................................................................................................25
3.4 Combination with Resource Allocation...............................................................................26
Chapter 4
Subcarrier Allocation Algorithm ...................................................................................................29
4.1 Dynamic subcarrier allocation (DSA)..................................................................................33
4.2 Constructive Initial Allocation (CIA) ..................................................................................37
4.3 Amplitude Craving Greedy (ACG)......................................................................................39
4.4 Shift Subcarrier Allocation (SSA) .......................................................................................43
4.5 Complexity Comparison ......................................................................................................48
Chapter 5
Simulation and Comparison...........................................................................................................50
5.1 Simulation Parameter Setting...............................................................................................50
5.2 Individual Performance Comparison ...................................................................................51
5.2.1 Comparison of Individual Transmission Power............................................................51
5.2.2 Comparison of Individual Throughput .........................................................................54
5.2.3 Comparison of subcarrier efficiency.............................................................................56
5.3 Comparison of system performance ....................................................................................59
5.3.1 Comparison of symbol error rate ..................................................................................59
5.3.2 Comparison of bit error rate..........................................................................................62
5.3.3 Comparison of system throughput ................................................................................64
5.3.4 Comparison of Transmission Power .............................................................................67
Chapter 6
Conclusion and Future Work .........................................................................................................69
6.1 Conclusion ...........................................................................................................................69
6.2 Future Works........................................................................................................................70
Bibliography..................................................................................................................................71
List of Figures
Fig. 2-1 Bandwidth efficiency comparisons of FDM and OFDM systems .....................................4
Fig. 2-2 OFDM system block diagram ............................................................................................5
Fig. 2-3 Subdivision of the bandwidth into c N subcarriers ..........................................................6
Fig. 2-4 Multicarrier modulation .....................................................................................................6
Fig. 2-5 Cyclic prefix.......................................................................................................................8
Fig. 2-6 OFDM Discrete-time based band equivalent model ..........................................................9
Fig. 2-7 OFDMA system services architecture..............................................................................10
Fig. 2-8 Downlink OFDMA system ..............................................................................................11
Fig. 2-9 Subcarrier allocations in OFDMA system .......................................................................12
Fig. 2-10 Multi-path Environment .................................................................................................13
Fig. 2-11 Jakes’ model scheme ......................................................................................................15
Fig. 2-12 Structure of tapped-delay-line ........................................................................................16
Fig. 2-13 Multi-path fading channel, mobile velocity is 4 km/h ...................................................18
Fig. 2-14 Multi-path fading channel, mobile velocity is 40 km/h .................................................18
Fig. 2-15 IEEE 802.16 PHY/MAC reference system model .........................................................19
Fig. 3-1 Utility function of VoIP user............................................................................................23
Fig. 3-2 Utility function of IPTV user ...........................................................................................24
Fig. 3-3 Utility function of HTTP user ..........................................................................................26
Fig. 3-4 Panoramic view of resource allocation with the utility function......................................27
Fig. 3-5 Combination of utility functions in OFDMA systems .....................................................28
Fig. 4-1 Multipath frequency selective fading channel of users ....................................................31
Fig. 4-2 Ideal Subcarrier Allocation ..............................................................................................32
Fig. 4-3 Mathematical model of dynamic subcarrier allocation ....................................................34
Fig.4-4 Diagram of CIA.................................................................................................................35
Fig.4-5 Result of CIA allocation....................................................................................................36
Fig. 4-6 Possible swapping results of user1 and user 3 .................................................................37
Fig. 4-7 Flow chart of CIA algorithm ............................................................................................39
Fig. 4-8 Mathematical model of ACG algorithm...........................................................................40
Fig. 4-9 Flow chart of ACG algorithm ..........................................................................................42
Fig. 4-10 Scenario of DSA, CIA, ACG and SSA ..........................................................................44
Fig. 4-11 Scenario Flow chart of SSA ...........................................................................................45
Fig. 4-12 Detailed flow chart of SSA ............................................................................................46
Fig. 4-13 Math model of SSA........................................................................................................47
Fig. 5-1(a) Individual transmission power with six users..............................................................52
Fig. 5-1(b) Individual transmission power with six users and utility functions ............................52
Fig. 5-1(c) Individual transmission power with nine users............................................................53
Fig. 5-1(d) Individual transmission power with nine users and utility functions ..........................53
Fig. 5-2(a) Individual power with six users ...................................................................................54
Fig. 5-2(b) Individual power with six users and utility functions..................................................55
Fig. 5-2(c) Individual power with nine users.................................................................................55
Fig. 5-2(d) Individual power with nine users and utility functions ...............................................56
Fig. 5-3(a) Subcarrier efficiency with six users.............................................................................57
Fig. 5-3(b) Subcarrier efficiency with six users and utility functions ...........................................57
Fig. 5-3(c) Subcarrier efficiency with nine users...........................................................................58
Fig. 5-3(d) Subcarrier efficiency with nine users and utility functions .........................................58
Fig. 5-4(a) SER Comparison with six users...................................................................................59
Fig. 5-4(b) SER Comparison with six users and utility functions .................................................60
Fig. 5-4(c) SER Comparison with nine users ................................................................................60
Fig. 5-4(d) SER Comparison with nine users and utility functions...............................................61
Fig. 5-5(a) Comparison of BER with six users..............................................................................62
Fig. 5-5(b) Comparison of BER with six users and utility functions ............................................63
Fig. 5-5(c) Comparison of BER with nine users............................................................................63
Fig. 5-5(d) Comparison of BER with nine users and utility functions ..........................................64
Fig. 5-6(a) Comparison of System throughput with six users .......................................................65
Fig. 5-6(b) Comparison of System throughput with six users and utility functions......................65
Fig. 5-6(c) Comparison of System throughput with nine users .....................................................66
Fig. 5-6(d) Comparison of System throughput with nine users and utility functions....................66
Fig. 5-7(a) Comparison of transmission power .............................................................................67
Fig. 5-7(b) Comparison of transmission power with utility functions...........................................68

                                

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