| Summary: | 碩士 === 國立臺灣大學 === 電機工程學研究所 === 92 === There is no reliable MAC-layer multicast in IEEE 802.11 wireless LANs (WLANs). In recent years, WLAN has been a popular architecture, and thus providing reliable multicast to wireless users is an important issue.
Multicast refers to the mechanism that a sender transmits data to multiple receivers. In nature, stations transmit data by means of broadcasting in WLANs. Therefore applying multicast to WLANs is proper and efficient. However, a collision will occur if each multicast receiver immediately sends an ACK to the sender; so that the sender cannot recognize whether each receiver has received the data successfully. As a result, each multicast receiver will not send an ACK in reply, i.e., no reliability is guaranteed to multicast data in WLANs.
In this thesis, we propose three reliable MAC-layer multicast protocols to guarantee multicast reliability for IEEE 802.11 WLANs. They are: (1) ACK-based Multicast Protocol (AMP), (2) Enhanced Leader-Based Protocol (ELBP), and (3) NAK-based Multicast Protocol (NMP). These three protocols not only provide reliable multicast but also solve the hidden terminal problem.
We further analyze these three protocols in terms of the frame holding time at AP. The simulation results show that our analytical methods are proper and provide a good description for the proposed mechanisms.
|
|---|
