在IEEE 802.16 OFDMA-TDD系統下，DL-Burst排程機制是由多個矩形組成的二維空間。DL-burst是BS分配給SS的頻寬需求。在下行資源頻寬分配下，BS會因應每個SS在不同的Subchannel的CINR值選擇最適當的調變和編碼速率給每個SS。因此，為了追求更高throughput和capacity的系統下，BS會選擇最佳調變和編碼速率的Sub-channel給予每個SS。不當的DL-burst排程機制將會造成內部碎裂問題(Internal Fragmentation Problem, IFP)以及外部碎裂問題(External Fragmentation Problem, EFP)進而導致降低整體網路的效能。為了改善系統的效能，本論文針對已排程的Burst資源，提出Burst Adjustment, Overlapping, and Relocation(BAOR)機制，而在BRS機制中包含了Fragmentation Combination、Best Fit Relocation 和BOAS策略。BOS機制在可執行的情況下，可以讓內部碎裂slots重複地被使用。再經由BAS機制增加些微的MAP-overhead讓burst的配置型態有更多的配置種類，並隨著BRS機制的演算法，能因應配置環境做適當的變化調整burst，減少內部碎裂浪費和外部碎裂浪費，進而提升整體網路throughput。由實驗數據可以得知，本論文所提出的BAOR機制能改善已配置完成DL-Burst排程機制，可減少內部碎裂資源與外部碎裂資源浪費，提升網路資源利用率。

Downlink Resource is two-dimensional space composed of many rectangular downlink burst traffics. A DL-burst traffic is the bandwidth allocation for SSs allocated by the BS. In downlink bandwidth allocation, BS would select the robust modulation to each SS according to the CINR of allocated sub-channel for each SS. With view to reaching to the High throughput and system capacity in IEEE 802.16 OFDMA system, the BS selects the sub-channel with the high modulation and the coding rate. However, unsuitable burst placement scheduling causes Internal Fragmentation Problem (IFP) and External Fragmentation Problem (EFP) and then it causes the system capacity down. In order to improving the system efficiency, we propose a Burst Adjustment, Overlapping, and Relocation Schemes (BAOR). In the availability of BOS, the unused slots of IFP can be reused. By using BAS, it makes the allocated rules of the burst traffics variable in OFDMA system and BRS will reduce the unused slots of the IFP and EFP and increase the throughput of the system. From Simulation result, (BAOR) Schemes can improve efficiently IFP and EFP, and increase the resource utilization and system throughput.

第1章	緒論	                                       - 1 -
1.1	前言	                                       - 1 -
第2章	IEEE 802.16背景與相關文獻	               - 5 -
2.1	IEEE802.16背景	                               - 5 -
2.1.1	OFDMA Frame Structure介紹	               - 5 -
2.1.2	MCS(modulation and coding Scheme)	      - 11 -
2.2	問題描述	                              - 13 -
2.2.1	內部碎裂問題(Internal Fragmentation Problem)  - 13 -
2.2.2	外部碎裂問題 (External fragmentation Problem) - 15 -
2.3	Related work	                              - 16 -
第3章	Burst Overlapping and Adjustment Scheme	      - 19 -
3.1	Burst Overlapping Scheme(BOS)	              - 19 -
3.2	Burst Adjustment Scheme(BAS)	              - 22 -
第4章	Burst Relocation Schemes(BRS)	              - 27 -
4.1.1	Fragmentation Combination	              - 29 -
4.1.2	Best Fit Relocation	                      - 32 -
4.1.3	Shifting Relocation by BOAS	              - 34 -
第5章	實驗與模擬	                              - 38 -
第6章	結論	                                      - 45 -
Reference		                              - 46 -
附錄-英文論文	                                      - 48 -

圖目錄
Fig. 1.	TDD 模式[2]	                              - 6 -
Fig. 2.	OFDMA Frame Structure[2]	              - 7 -
Fig. 3.	Burst Location Definition[2]	              - 8 -
Fig. 4.	Burst的組成	                              - 9 -
Fig. 5.	MAC Header資訊[2]	                      - 9 -
Fig. 6.	DL-MAP_IE()[2]	                             - 10 -
Fig. 7.	Data mapping[2]	                             - 13 -
Fig. 8.	內部碎裂問題	                             - 14 -
Fig. 9.	Burst重疊利用機制	                     - 20 -
Fig. 10.The Feasibility of BOS	                     - 21 -
Fig. 11.DL-Burst allocation	                     - 22 -
Fig. 12.IFP Parameters in DL-MAP_IE()	             - 23 -
Fig. 13.Burst Adjustment types	                     - 24 -
Fig. 14.Burst型態組合	                             - 24 -
Fig. 15.The example of BAS and BOS.	             - 25 -
Fig. 16.Defination of the Bursti	             - 28 -
Fig. 17.碎裂空間集合	                             - 30 -
Fig. 18.Example of Fragmentation Combination	     - 31 -
Fig. 19.配置區域空間	                             - 33 -
Fig. 20.Shifting Relocation by BOAS(1)	             - 36 -
Fig. 21.Shifting Relocation by BOAS(2)	             - 37 -
Fig. 22.Average Throughput	                     - 39 -
Fig. 23.Number of Service SS	                     - 40 -
Fig. 24.Average Utilization Ratio	             - 41 -
Fig. 25.Average Throughput (BOAS vs.without BOAS)    - 42 -
Fig. 26.Number of Service SS(BOAS vs.without BOAS)   - 43 -
Fig. 27.Utilization(BOAS vs.without BOAS)            - 44 -

表目錄
表.1.	Modulation and Coding rate, MCS[2]	     - 12 -
表.2.	實驗相關參數	                             - 38 -

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