臺灣博碩士論文加值系統

以第三代3G無線網路或即將到來的4G無線網路等相關蜂巢式網路都是提供高速網路服務的一個基礎架構，大量的多媒體網路應用軟體及更多的語音連線將耗用其頻寬，同樣地也會使用更多的頻道資源，因此需要高效率的頻道分配技術，藉此提高頻道資源的使用率，降低斷線率及阻塞率。為此，提出階層式的蜂巢網路(HCN)，將各別種類的交通分配到不同規模大小的蜂巢上，進行通訊。在本研究中，主要將交通量分類為普通語音及多媒體通訊，並將蜂巢式網路分為二個階層，分別運載語音和多媒體交通量以提高服務容量。根據其無線頻道劃分特性，傳統語音連線將主要由macrocell 服務，而多媒體連線則由microcell承載其交通量。在本研究中提出，將以CDMA技術的，當網路擁擠導致macrocell 頻道資源不足時，語音連線將可以轉由microcell來運載。而於多媒體通訊中，非即時傳輸的多媒體及資料通訊可以容許較長時間的等候，因此於microcell中加入頻道連結集合技術用增加收容持續增加的連線需求數，藉以提高整個系統的服務品質。

Nowadays, both wireless network technology and coverage are widely developing and more mature. 3G or upcoming 4G cell based wireless network is the infrastructure in order to provide more high speed network services. No doubt, a large number of multimedia applications and more voice calls will consume more bandwidth as well as channel resources. An efficient channel assignment scheme could increase resources utilization and decrease drop rate and blocking rate. Therefore, the hierarchical cellular network is proposed for solving this issue. According to the basic rule of channel assignment, the different types of wireless traffic will be assigned to specific cellular or base station. In out study and model, we defined two types of traffic, voice call and multimedia data call which will be carried or transported by macrocell and microcell separately. When network congestion occurs and macrocell has no channel available, voice call is able to be transferred by microcell in stead of macrocell. For multimedia data call, the character of non real-time data transfer is allowed a longer waiting time. Therefore, we created a “channel pool” to collect these calls in order to decrease the possibility of overall block rate and to increase the system utilization.

ACKNOWLEDGEMENTS I
摘要 II
Abstract III
TABLE OF CONTENTS IV
TABLE OF FIGURES V
TABLE OF TABLES VII
CHAPTER 1 INTRODUCTION 1
CHAPTER 2 相關研究及模型RELEATED MODELS 3
2.1 Guard Channel 3
2.2 Sub-Rating 4
2.3 Overflow 5
CHAPTER 3 所提出方式及模型PROPOSED MODEL 10
3.1 前述方法的優缺點 10
3.2 針對前述方法的缺點改善 13
3.3 提出方法詳述 14
3.4 Design Considerations 17
3.5 等待pool頻道的切割原則 18
3.6 new call及handoff call採取的pool的權重分配策略 18
3.7 無線終端設備的等待時間準則 19
CHAPTER 4 模型之模擬結果SIMULATION RESULTS 20
4.1 以不同類型頻道分配方式的模擬測試。 21
4.2 啟用頻道連結集合，給予不同數量的集合及不同等待間長短。 23
CHAPTER 5 CONCLUSIONS AND FUTURE WORKS 29
REFERENCE 30

[1]X. Wu，J. Zheng，E. Regentova，and Y. Jiang，Analysis of the Effect of Channel Sub-rating in Unidirectional Call overflow Scheme for Call Admission in Hierarchical Cellular Networks，IEEE 65th Semi-Annual Vehicular Technology Conference，Spring 2007，Dublin，Ireland.

[2] Taesoo Kwon，Dong-Ho Cho，Department of Electrical Engineering and Computer Science Korea Advanced Institute of Science and Technology (KAIST) ，Adaptive Radio Resource Management Based on Cell Load in CDMA Based Hierarchical Cell Structure，Vehicular Technology Conference，2002.

[3] Yi-Bing Lin，Anthony R. Noerpel，Senior Member，IEEE，and Daniel J. Harasty ，
The sub-rating Channel Assignment Strategy for PCS Hand-Offs，IEEE TRANSCATIONS ON VEHICULAR TECHNOLOGY，VOL. 45 NO. 1，FEBRUARY 1996

[4]Wei Kuang Lai，Member，IEEE，Yu-Jyr Jin，Hsin Wei Chen，and Chieh Ying Pan
Channel Assignment for Initial and handoff Calls to Improve the Call-Completion Probability. IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY，VOL. 52，NO. 4，JULY 2003