Research On Key Technologies Of Wireless Local Area Network

Wireless local area network (WLAN) develops rapidly. As the mainstream of WLAN standard, IEEE802.11continues to develop and improve the current WLAN standards. It introduces or is about to launch new protocols to meet the demand of development. Although existing IEEE802.11n standard comprehensively enhances network throughput which can support data rate up to600Mbit/s, with the development of wireless communication services and broadband data services, it has put forward higher requirements for the data rate and throughput. In addition, wireless resources, especially the spectrum resources become more and more tense. How to make more efficient use of limited communication resources to achieve high throughput, low-cost WLAN services has become the focus of the development of new technologies in future WLAN.This paper researchs heated discussed high data rate WLAN standards IEEE802.11ac and IEEE802.11ah physical layer key technologies. On this basis, the joint coding and modulation diversity scheme for WLAN is proposed. It applies two-dimensional modulation diversity to current IEEE802.11ac standard transmission scheme. Through the component interleavers that jointly use of the three dimensions of time, frequency and space, proposed scheme can take full advantage of the coding-gain of channel codes, the time and frequency diversity of OFDM system and the spatial diversity of MIMO all together. Simulation results demonstrate the proposed scheme can achieve significant performance advantages compared with the current standard scheme for the different coding systems, the different propagation environments and the different configuration of antennas and spatial streams. What’s more, for the IEEE802.11ah MCS0repeat scheme, the compatible1/4code rate BCC scheme is proposed. On the basis of minimization the increase of complexity, it can further obtain coding gain. Compared with the current standard scheme proposed scheme can achieve nearly1dB SNR gain. In short, the proposed schemes are efficient, reliable and robust. They are suitable for future development needs of the W LAN.