Quoc-Tuong NGO

摘要: In the early decade of this century, it is apparent that wireless communication technologies have an exponential growth. Various communication techniques have been employed to serve various demands of high-speed wireless links such as higher data rate, increased robustness, and greater user capacity. The next generation of wireless communications is based on an all-IP switched network and can provide a peak data rate up to hundreds of Mbits/s for high mobility, and to Gbits/s for low-mobility end-users. For instance, the Wi-Fi standard (IEEE 802.11 n) can provide a data rate up to 600 Mbps in physical layer, and the Wi-Max standard (IEEE 802.16) can support a gross data rate up to 100 Mbps for mobile network.One of the most well-known techniques for wireless communications is multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM). This technique not only offers diversity and capacity gains but also achieves higher spectral efficiency and higher link reliability in comparison with single antenna or single carrier systems. The benefits of MIMO communication are generally ensured by both openloop and closed-loop MIMO techniques. The open-loop techniques, such as space time coding (STC) and spatial multiplexing (SM), are used without the need for channel state information (CSI) at the transmitter. In order to overcome the multipath effect and improve the robustness of spatial multiplexing systems, linear precoding closed-loop techniques can be used at the transmitter. The principle of the precoding techniques is that, when the channel knowledge is available at the transmitter, the transmit signal is …