The rapid development of Wireless Local Area Network (WLAN) has not yet broken the bottleneck that the low transmission speed hinders the further development of WLAN. Now, some key technologies for next generation mobile communications can solve the problem by supporting high-speed transmission and ensuring reliable performance. IEEE 802.11n has made general amendment to 802.11. Based on IEEE 802.11n, the transmission speed can be doubled by the application of Orthogonal Frequency Division Multiplexing (OFDM) and Multiple Input Multiple Output (MIMO) technologies on the physical layer. In addition, the enhanced Medium Access Control (MAC) system performance, optimized data frame and improved network throughput can all be achieved by the adoption of frame convergence, Transmission Opportunity (TXOP) and block-acknowledge technologies on the MAC layer. A new error correction method, called Low Density Parity Check Code (LDPC), can also be adopted for the receiver to enjoy low Bit Error Ratio (BER) with low S/N, thus improving signal coverage.
Chen Yanhui (State Key Lab of Integrated Service Networks, Xidian University, Xi’an 710071, China)
