家用無線網路媒體存取協定之模型建立與評估

Abstract

在今日的家庭中，個人電腦、家電與通訊產品的使用已經相當普及，但是卻缺乏彼此整合的介面與協定。為了建構完整的家用無線網路，提供更便利、更多元化的服務，通訊與資訊業界相繼合作發展整合無線聲音與資料的傳輸標準，而主要的兩個計畫分別是HomeRF與 Bluetooth。在HomeRF計畫中提出的媒體存取協定SWAP (Shared Wireless Access Protocol) 中，聲音使用者與資料使用者分別使用分時多重進接 (Time Division Multiple Access) 與載波偵測多重進接/碰撞避免 (Carrier Sense Multiple Access/ Collision Avoidance, CSMA/CA) 的方式來存取頻道。Bluetooth計畫中則是則是使用不同類型的連結控制來處理聲音與資料的應用，並以輪詢 (Polling) 的方式來分配頻寬。本論文主要將介紹此兩種協定, 並針對兩者的缺點，提出一個改良的通訊協定：集中排程－分散跳頻多重進接 (Centralized Scheduling－Distributed Hopping Multiple Access) 。此協定中每個使用者使用各自獨立的跳頻序列，透過一個共用頻道與中央單元，來分配傳輸的排程.降低了輪詢機制中隨時聆聽其他使用者傳輸需求的頻寬浪費，並提高ISM頻帶的頻寬使用率及效率.本論文將針對上述三種協定，建立其模擬模型,並分析其優劣。在模擬結果中，我們發現集中排程－分散跳頻協定在系統的總傳輸量、聲音與資料的整合，與封包的延遲上都有較佳的表現。

Personal computers, consumer electronic devices, and telecommunication products are widely used in today's family. To integrate these products and provide wireless connectivity at home, many industrial standardization activities are moving. Two major projects are HomeRF and Bluetooth. In HomeRF project, SWAP (Shared Wireless Access Protocol) are proposed to support voice and data transmissions by TDMA (Time Division Multiple Access) and CSMA/CA (Carrier Sense Multiple Access) method respectively. In Bluetooth project, differnet types of links are used for voice and data transmissions, and polling scheme is applied. In this thesis, we will introduce these two MAC protocols. Furthermore, we propose an improved MAC protocol which is called Centralized-Scheduling Distributed-Hopping Multiple Access. In the protocol, terminals have their individual hopping sequence. They communicate with each other by a common channel of a central unit. We construct the simulation models for these three MAC protocols and evaluate the performance of them in this thesis. We found CSDH protocol have better performances in system throughput, voice/data integration, and packet delay than the other two protocols.