| The third generation mobile communication (referred to as3G) propels development of global mobile communication market like an engine for development of mobile communication market. And the services of3G also bring a huge volume of traffic. Telecommunication operators have an urgent need for other technologies to transfer these huge volumes of traffic. Recently, with advantages of high throughput, low cost, and so on. WLAN has been taken account increasingly by operators, and as it an important part of the fixed network and cellular network, mass deployment of WLAN has been done greatly promoted the development of the WLAN. Formulation and development of the WLAN standard also provide the development of the WLAN technology and compatibility guaranteed meanwhile. WLAN standard has been widespread concerns around the world. Many telecommunication manufacturers and operators actively take part in developing the standards of WLAN. The main WLAN standard is the standard of IEEE802.11now. Since the first WLAN standard of IEEE802.11was born in1997, so far has formed dozens of versions, involving the content of safety, quality of service, spectrum management, network interfusion, technology of new application. IEEE802.11ac is one of the latest WLAN standards being working on, the goal is achieving data transfer rate of1Gbit/s below the frequency bands of6GHz.In order to support the new generation of very high throughput WLAN standard, a series of breakthrough should be achieved in key technologies. High throughput transmission of the new generation WLAN also propose a new challenge to WLAN MAC layer. On the one hand, traditional WLAN MAC transport mechanism is simple to realize, on the other hand, this mechanism restricts the efficiency of the MAC layer, reducing the utilization of wireless resources in the system. With the sharp increase of the wireless network traffic, users are looking forward to an effective, robust quality of service guaranteed while enjoying high speed broadband wireless access. The quality of service guaranteed means not to increase the data transmission delay when wireless bandwidth sufficient, while lacking of wireless bandwidth, it can give priority to ensuring the transmission of high priority services, and accurate, flexible to adjust the proportion of bandwidth between users. The key technologies of IEEE802.11ac is being working in this thesis, the key technology routes of the IEEE802.11ac are multi-antenna and wider channels following the high speed WLAN standard IEEE802.11n. And the technologies of channel bonding, MU MIMO and frame aggregation are used to boost data speeds to1Gbit/s. The technologies of channel bonding, multi-user MIMO, frame aggregation are introduced in this context. As lacking of QoS support in WLAN standard IEEE802.11ac, a new channel bonding mechanism based on the quality of service was proposed, according to the different priorities of the traffic, and bonding a different number of channels selectively for multichannel data transmission. Channel model established by MATLAB. Simulation results show that the proposed channel bonding mechanism not only improving the throughput, but also reducing the data transmission delay. This method reduces the network congestion while providing quality of service guaranteed. More in line with the needs of the very high throughput wireless local area network than the traditional channel bonding. |
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