A study on entrance link employing MIMO/unsymmetrical STBC scheme in wireless lan service over high-speed vehicle environments

To solve the problem of traffic proliferation in the mobile communications, traffic offload over wireless LAN systems has been proposed as the one of promising solutions. High-speed and large-capacity communication has been realized by wireless LAN systems, but in the high-speed moving environments, BER performances degrade due to influence of Doppler frequency spread. In this study, the entrance link using the IEEE802.11ac standard for public wireless LAN services in high-speed trains is proposed for improving the capacity of the whole system by employing not only MIMO (Multiple Input Multiple Output) to increase the transmission rate, but also STBC (Space-Time Block Coding) to extend the distance. By applying unsymmetrical STBC for up and down-link, the communication distance between a base station and a train can be extended and it is confirmed by simulation including a passing pattern and stopping/starting pattern that the communication capacity can be increased.