(A) high throughput and security enhanced wlan mac system implementation

Abstract

With the growing demand for high-performance multimedia applications over wireless channels, it is necessary to develop a Medium Access Control (MAC) system that supports high throughput and quality of service enhancements. This dissertation presents the standard analysis, design architecture and design issues leading to the implementation of an IEEE 802.11e based MAC system that supports MAC throughput of over 100Mbps. In order to meet the MAC layer timing constraints, a hardware/software co-design approach is adopted. The proposed MAC architecture is implemented on the Xilinx Virtex-II Pro Field-Programmable Gate Array (FPGA) (XC2VP70-5FF1704C) prototype, and connected to a host computer through an external Universal Serial Bus (USB) interface. The total FPGA resource utilization is 11,508 out of 33,088 (34%) available slices. The measured MAC throughput is 100.7Mbps and 109.2Mbps for voice and video access categories, transmitted at a data rate of 260Mbps based on IEEE 802.11n Physical Layer (PHY), using the contention-based hybrid coordination function channel access mechanism. For further MAC throughput enhancement, the Task Group z (TGz) was set up to define a new Direct Link Setup (DLS) mechanism known as Tunneled Direct Link Setup (TDLS) that establishes a bidirectional direct link from one non-Access Point (AP) station to another non-AP station within the same infrastructure Basic Service Set (BSS). TDLS is compatible with existing non-DLS or DLS capable AP. TDLS allows channel switching operation to enhance network throughput. This gives a clear advantage over the IEEE 802.11e based DLS. Under short communication distance, TDLS may save half of the data transmission and even benefit from higher-rate Modulation and Coding Scheme (MCS). However, since the wireless channel is not ideal and the transmit station may be located far from the receive STA, the use of TDLS may deteriorate the MAC throughput. Therefore, a dynamic TDLS MAC algorithm is propo...