Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/6339
標題: IEEE 802.11無線區域網路之集中與分散協調功能之效能分析
Performance evaluation of PCF and DCF in IEEE 802.11 Wireless LAN
作者: 陳英隆
chen, eing long
關鍵字: Wireless LAN;無線區域網路
出版社: 電機工程學系
摘要: 
摘 要
由於無線區域網路不需設纜線的特性,讓使用者不受地形上的限制,進而可
擴大其活動範圍,而且使得高移動性成為無線區域網路之主要優勢。因此,
許多無線區域網路之應用也隨著應蘊而生。而在網路產品互通的原則下,
目前已有兩種無線區域網路標準:HIPERLAN及IEEE 802.11問世。其中,
IEEE 802.11規範了實體層( Physical layer,PHY )與介質存取控制層(
Medium access control layer, MAC )。而介質存取控制層( MAC )中又
規範了分散式協調功能( DCF )與集中式協調功能( PCF )。在論文中,我
們將針對IEEE 802.11無線區域網路標準中以具有碰撞避免之載波感測多
重存取( CSMA/CA )為基礎的介質存取控制( MAC )層,其各種通訊協定與
網路型態的互動關係的效能( Throughput )及時間延遲( Delay ),加以分
析比較。而各項通訊協定中,我們將分析並模擬基本存取方式,要求傳送與
允許傳送( RTS/CTS ),功率控制機制( Power management mode ),組成式
無線區域網路( Infrastructure WLAN ),臨時組成式無線區域網路( Ad-
hoc WLAN ),以及訊框錯誤率( Frame error rate )等對效能與時間延遲
之影響。並且就可提供限時服務(如:聲音)之集中式協調功能,模擬分析其
通訊協定的效能與時間延遲。此外,我們將在可同時使用DCF與PCF之情況
下,模擬在不同的資料輸入負載時,DCF與PCF使用之時間比例對系統之效能
與時間延遲的影響。藉由適當的分配集中式協調功能和分散式協調功能之
時間比例,我們將可使支援限時服務之IEEE 802.11無線區域網路系統的使
用率與效能提高。

The wireless LANs been used in environments, such as
manufacturing floors, conventions and historic buildings, where
cable installation is expensive or impractical. Furthermore,
wireless systems and networks will not only provide
communication capability between mobile terminals but will also
permit these mobile devices to have access to "wired" networks.
Hence, wireless local networks have become an emerging
technology for today's computer and communication industries.
There are two kinds of standards of the wireless LAN: HIPERLAN
and IEEE 802.11. The IEEE 802.11 specifies the medium access
control (MAC) layer and physical layer. The MAC layer contains
two access methods:Distributed Coordination Function (DCF) and
Point Coordination Function (PCF)which support asynchronous data
transfer and time bounded service, respectively. In this
thesis, we will concentrate on the analysis of the MAC protocols
of IEEE 802.11 wireless LAN standard. We compare the performance
of the various data transfer protocols that are part of the
802.11 WLAN MAC protocol. We present the simulation and analytic
results on the Request To Send (RTS)/Clear To Send (CTS) message
exchange, power mangement mechanism and frame error rate for the
infrastructure wireless LAN and ad-hoc wireless LAN of DCF.
Besides these, we will conduct performance evaluation fo the PCF
protocols and taking intoaccount the using time ratio of DCF and
PCF. According to our simulations, theDCF and PCF will perform
satisfyingly by adjusting their using time ratio properly.
URI: http://hdl.handle.net/11455/6339
Appears in Collections:電機工程學系所

Show full item record
 

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.