Mathematical Modeling And Simulated Analysis Of OFDM-MIMO Based On IEEE 802.11ac

As an important forms of broadband access technology, WLAN(wireless local area network) technology has developed rapidly and been widely used in recent years. But with the wireless network traffic becomelarger, the current standard 802.11 n used by WLAN has been unable to meet user's demand for bandwidth. Faced with this trend, IEEE developed a new protocol named802.11 ac in 2013.The paper based on IEEE 802.11 ac protocol draft 2.0,deeply researched its physical layer and built its system model by MATLAB. Compared to 802.11 n, 802.11 ac improved throughput andMIMO structure.Inthroughput,802.11 ac increased channel bandwidth up to 160 MHz and spatial streams up to 8, in addition,increased the 256 QAM modulation. In MIMO structure,802.11 ac proposed MU structure.Multiple users can transmit data in the same time-frequency resources, which further improved the spectral efficiency of the system. In response to these changes,the paper first gives the physical layer structure for 802.11 ac,then bulids encoder parser,coding,stream parser,segment parser,interleaving,tone mapping,QAM modulation,STBC,the frequency domainto the time domain conversion modules in transmitter and the time domainto the frequency domain conversion,channel estimation and signal detection,demodulation,de-interleaving,decoder modules in receiver.When building model for these modules,the paper was worked in two aspects. On the one hand, configuration and improve algorithm for each module according to the parameters set by the system throughput.For example, when bandwidth is 160 MHz and modulation method is 256 QAM,segment parser module will be added to transmitter and parameters for this situation will be configured.On the other hand,thepaper research and modeling pre-coding module that can inhibit the mutual interference that between in the downlink user receiver.After 802.11 ac system model has completed,thepaper has run simulation for some key module such as pre-coding and signal detection to see if they are functioning properly and select better algorithm.Finally,the paper has run simulation for the whole system andsimulation results shows that the model can achieve the performance proposed by 802.11 ac,all of these lay the foundation of hardware implementation of 802.11 ac.