3 research outputs found
A Cluster-Tree-Based GTS Allocation Scheme for IEEE 802.15.4 MAC Layer
No full textZigBee屬於無線個人區域網路(Wireless Personal Networks：WPAN)，其底層運用的IEEE802.15.4通訊標準主要為「低資料速率─無線個人區域網路(Low Rate-Wireless Personal Area Network,LR-WPAN)」的協定。IEEE 802.15.4標準可提供使用免競爭週期(contention-free period；CFP)來傳送資料，對於感測網路負載較高或有服務品質要求(Quality of Service；QoS)時，縮短延遲以提高資料傳輸時的效率，進而提升網路的效能。
IEEE 802.15.4標準中定義了免競爭週期所使用保證時槽傳輸之方式，此機制是由裝置經申請成功配置後才得以使用，且裝置在申請時須先取得通道使用權才能申請配置，但此方式在網路流量負載大時及競爭者多的情況下，裝置不易取得通道使用權，將導致免競爭週期的利用率降低而降低網路的效能。為了解決免競爭週期無法有效利用的問題，本篇論文提出保證時槽預先配置之機制，利用ZigBee中網路位址分配的參數Cm及Rm來預先配置保證時槽，減少申請保證時槽時所發送的控制封包量，在網路拓樸建置完成的前提下，使裝置能有自己的保證時槽傳輸而不需經由競爭申請的步驟，如此可提升免競爭週期保證時槽的使用率，藉此來縮短資料傳遞延遲及能量的消耗。
由模擬的結果，在本篇論文使用之機制與IEEE 802.15.4標準之機制相較下，資料平均傳遞延遲及平均能量的消耗都有明顯的降低，在預先配置的機制下裝置可大幅減少整體控制的封包量，使保證時槽充分的利用，藉此機制能有效的讓各個裝置有公平的傳輸頻寬以提升網路效能。The IEEE 802.15.4 standard can use contention-free period to transmit,the data when we ask for higher sensor network load or quality of service. It can improve the efficiency of data transmission by shorten delay and improve the efficacy of network, the way contention-free period used to transmit Guarantee Time Slot is by successfully configurate the device. And the device must obtain the right to use channel in order to to apply the configuration. But this way when network load is large and more competitors the device is not easy to obtain the right to use channel. It will decrease contention period utilization and reduce network efficacy.
IEEE 802.15.4 standard defines the use of free contention cycle of guaranteed time slot transmission mode, this mechanism is allocating by the device after the application is successful after they use, and the device channel in the application must obtain the right to use in order to apply the configuration. But this way network traffic load is large and competitorsand more cases, the device is difficult to get access right to use, free contention would lead to decreased utilization and reduce cycle network performance.
To address the contention-free period can not effectively use issues, this paper put forward to ensure that the mechanism of pre-allocate time slots , the use of ZigBee network address allocation in the parameters Cm and Rm to ensure pre-allocate time slots. Applying for guaranteed time slots when the amount ofcontrol packets sent in the complete network topology built under the premise of the device, can have its own time slot to ensure transmission without contention through the application procedure, so can enhance contention-free period ensure the utilization of time slots, thereby to shorten the data delivery delay andenergy consumption.
By the simulation results, the mechanism used in this paper with the IEEE 802.15.4 standard mechanism for comparison, the average data transmission delay and average energy consumption has significantly reduced, the mechanism in the pre-allocate devices can significantly reduce the overall the amount of controlpackets. So that when the slot to ensure full utilization of this mechanism can effectively so that all devices havefair bandwidth to improve network performance.摘要 ii
第1章 緒論 1
1.1 前言 1
1.2 研究動機與目的 3
1.3 章節概要 5
第2章 相關研究 6
2.1 競爭式(CONTENTION-BASED) MAC PROTOCOLS: 7
2.1.1 S-MAC[20]: 8
2.1.2 T-MAC[21] 9
2.1.3 Masked-node problem[28]: 10
2.2 時槽式MAC PROTOCOL: 11
2.2.1 BMA[32]: 12
2.2.2 TRAMA[33] 13
2.2.3 TDMA-W[34] 15
2.3 IEEE 802.15.4/ZIGBEE協定相關研究 16
第3章 IEEE 802.15.4與ZIGBEE標準規範 20
3.1 簡介 20
3.1.1 ZigBee的主要特性 20
3.1.2 ZigBee應用的領域 23
3.2 IEEE 802.15.4與ZIGBEE標準規範 25
3.2.1 IEEE 802.15.4介紹 26
3.2.2 IEEE 802.15.4 標準所定義的LR-WPAN 具有以下特點： 27
3.2.3 網路拓樸 28
3.2.4 IEEE 802.15.4 實體層(PHY LAYER)介紹 29
3.2.5 IEEE 802.15.4 媒介存取控制層(MAC LAYER)介紹 31
3.2.6 超訊框結構(SUPERFRAME STRUCTURE) 35
3.2.7 載波感測多重存取/碰撞避免(CARRIER SENSE MULTIPLE ACCESS WITH COLLISION AVOIDANCE, CSMA/CA )機制介紹 37
3.3 資料傳輸模型(DATA TRANSFER MODE) 41
3.3.1 訊框格式 44
3.4 ZIGBEE網路層通訊協定 54
3.4.1 ZigBee網路位址分配演算法 56
3.4.2 ZigBee網路路由協定 58
第4章 保證時槽重新分配方法 61
4.1 問題描述 61
4.2 新GTS參數配置介紹 62
4.3 保證時槽配置流程 65
4.4 父裝置與子裝置GTS配置後關係 70
第5章 模擬結果分析 74
5.1 環境架構 74
5.2 資料傳遞路徑模擬 78
5.3 模擬結果分析 86
第6章 結論與未來研究方向 89
參考文獻 9
A MAC Layer Allocation Method for IEEE 802.15.4 Based on GTS Mechanism
No full text在現在社會中行動通訊商品日新月異，隨著科技進步，無線網路扮演生活上不可或缺的角色，ZigBee無線網路提供了低傳輸資料速度及無線個人區域網路(Wireless Personal Networks：WPAN)，ZigBee的MAC層所使用的是IEEE 802.15.4通訊標準，此協定針對低資料速率及傳輸時間慢，它提供了免競爭週期(Contention-Free Period；CFP)來傳送資料，保證資料傳輸的完整性，減少傳輸碰撞，提高資料傳輸時的效率，進而提升網路的效能。
IEEE 802.15.4協定中定義了免競爭週期所使用的保證時槽(GTS)傳輸方式保證不會有其他裝置與他相衝，而每個裝置必須先取得通道使用權才能申請配置保證時槽，若在網路流量負載大時或當競爭通道者多時的情況下，每個裝置很難去取得通道的使用權，在這種情況下時，導致免競爭週期的使用率、網路的效能降低。[1]研究提出利用ZigBee中網路位址分配的參數Cm及Rm來預先配置給各個裝置保證時槽取代競爭通道的方式來改善網路效能，但免競爭週期仍無法被有效利用，本研究提出改進[1]對保證時槽預先配置之機制，依照各裝置的網路位址大小將免競爭時槽依比例方式配置給各裝置，將比[1]更善用免競爭週期，不只減少競爭週期使裝置能有自己的保證時槽傳輸而不需經由競爭申請的步驟，降低傳統競爭時的碰撞，更提升免競爭週期保證時槽的使用率，藉此來縮短資料傳輸時間。
由實驗結果顯示，本篇論文與[1]使用預先配置之機制與IEEE 802.15.4標準之機制相較之下，平均傳輸的時間及平均保證時槽的使用率都有明顯的優勢，藉此機制能有效提升網路效能。As technology advances, mobile communication commodities change and improvement progress with each passing day. Wireless networks play an indispensable role in our life.
In [15] has been the release of IEEE 802.15.4 standard that defines the medium access control (MAC) layer and the physical (PHY) layer for low-rate, wireless personal area network (LR-WPAN). [15] also defines contention avoidance period (CAP) and the contention free period (CFP) to improve wireless network performance. Upper layers are defined by ZigBee Alliance.
Before transmission data, every guarantee time slot (GTS) must be allocated for each device during CFP through the CAP. However, it is hard to get the access right of using GTS when there have more devices to share the bandwidth within the same period. It also leads to decrease utilization and reduce cycle network performance. [1] proposed the method of adopting the pre-allocated GTS by ZigBee network address parameters Cm and Rm to cope with the contention issues.
However, the utilization of CFP is low by the method mentioned in [1]. In this paper, a ratio GTS allocated scheme is presented to improve the problem of more devices to share the bandwidth within the same period. In addition, we proposed the method for GTS allocation not only conduct the pre-allocation mechanism without CAP, but also raise the utilization of CFP and reduce transmission time.目次
第一章 緒論 1
1.1 前言 1
1.2 研究動機與目的 2
第二章 相關研究 6
2.1 簡介 6
2.2 相關研究 7
2.2.1 A New GTS Allocation Scheme (NGA)[18] 7
2.2.2 I-GAME[17] 8
2.2.3 EMGA[21] 9
2.2.4 A Cluster-Tree-Based GTS Allocation Scheme for IEEE 802.15.4 MAC Layer[1] 10
第三章 IEEE 802.15.4與ZIGBEE標準規範 13
3.1 簡介 13
3.1.1 ZigBee特性 13
3.1.2 ZigBee應用的領域 16
3.2 IEEE 802.15.4與ZIGBEE標準規範 17
3.2.1 IEEE 802.15.4介紹 18
3.2.2 IEEE 802.15.4 標準所定義的LR-WPAN 具有以下特點： 19
3.2.3 網路拓樸 20
3.2.4 IEEE 802.15.4 實體層(PHY layer)介紹 21
3.2.5 IEEE 802.15.4 媒介存取控制層(MAC layer)介紹 24
3.2.6 超訊框結構(superframe structure) 28
3.2.7 載波感測多重存取/碰撞避免(Carrier Sense Multiple Access with Collision Avoidance, CSMA/CA )機制介紹 30
3.3 資料傳輸模型(DATA TRANSFER MODE) 33
3.3.1 訊框格式 36
3.4 ZIGBEE網路層通訊協定 46
3.4.1 ZigBee網路位址分配演算法 48
3.4.2 ZigBee網路路由協定 50
第四章 保證時槽比例分配方法 53
4.1 問題描述 53
4.2 基本架構 54
4.2.1 節點資料 54
4.2.2 保證時槽配置 55
4.3 保證時槽配置流程 58
4.4 GTS容錯配置 64
第五章 模擬結果分析 66
5.1 環境架構 67
5.2 資料傳遞路徑 67
5.3 實驗模擬結果 68
5.4 模擬結果分析 76
第六章 結論與未來研究方向 78
參考文獻 7
