| Summary: | 碩士 === 中原大學 === 電機工程研究所 === 97 === The latest generation of wireless LAN standards: 802.11n, a major technical challenges. With the participation of the multi-antenna multi-bandwidth, in line with the 802.11n standard WLAN components must also be in the output power, size and other aspects of optimization. The 802.11n wireless circuit design engineers, to consider factors such as integrity, power, performance, filtering, isolation and throughput.
Wireless network design and deployment of a key principle is to monitor, control and centralization of assigned functions. The experiments show that concentration of a large number of network equipment development and implementation of the harmonization of policies the best way, whether they focus on the same physical equipment location or scattered in different geographical regions. A centralized wireless network architecture in order to be effective, relevant information must be continuously transmitted to the central management of the network equipment (such as the wireless network switches / equipment). If there is no overall, precision and update rate of millisecond-level status information of the wireless environment, the center equipment will not be able to make accurate decisions. At the same time, if the central controller in all of the access point operation, which may affect the timing of those on the function of special sensors. Therefore, we must find a balance in which.
MAC transmission offers two services: a distribution coordination function using CSMA / CA, non-real-time information for transmission. Coordination function controlled by the network coordinator and a way to polling station to send the time frame and sequence. Transmission as a result of the workstation can be pre-arranged time, the transmission delay can provide a guarantee of service. Frame aggregation is the key to the necessary technology, the so-called Frame aggregation is combined with many small packets into a big packet, it would have to go through many times of packet-switching MAC control steps, and now can be as long as a large number of data of the past, so the MAC can be reduced overhead transmission efficiency can be improved. Link frame can be done in the MAC layer, as long as the receiving end in accordance with header information, using the corresponding methods will receive a large packet of the small opening into the original packet.
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