Abstract: A frequency offset estimation and correction method in an orthogonal frequency division multiplexing (OFDM) system is disclosed in present invention, including: obtaining a pilot frequency domain channel estimation value of a target user, and smoothing the channel estimation value in frequency domain; obtaining the link quality state of a receiver; adopting a history smoothing algorithm or a multi-branch attempt algorithm to perform frequency offset estimation and frequency offset compensation, performing frequency domain demodulation for the data for which frequency offset compensation has been performed, and outputting a link quality state parameter; and updating the link quality state of the receiver according to the link quality state parameter, determining the output value of this frequency offset estimation and outputting a history frequency offset value required by next frequency offset estimation according to the determined output value of this frequency offset estimation.

Abstract: The disclosure provides a downlink transmission method and an eNodeB in a multiple input multiple output system. The method includes: obtaining channel quality indication of a User Equipment (UE) to generate a channel condition indication value; obtaining channel rank indication of the UE to generate a channel correlation indication value; obtaining uplink channel impulse response estimation data of the UE to generate a channel variation state indication value; selecting a downlink transmission mode according to the channel condition indication value, the channel correlation indication value and the channel variation state indication value; transmitting data to the UE in the selected downlink transmission mode. Because of extracting information from a current channel as a basis of a subsequent selection of the downlink mode, the disclosure can greatly improve a resource utilization ratio of a system and realize a better wireless transmission effect.

Abstract: The disclosure provides a downlink transmission method and an eNodeB in a multiple input multiple output system. The method includes: obtaining channel quality indication of a User Equipment (UE) to generate a channel condition indication value; obtaining channel rank indication of the UE to generate a channel correlation indication value; obtaining uplink channel impulse response estimation data of the UE to generate a channel variation state indication value; selecting a downlink transmission mode according to the channel condition indication value, the channel correlation indication value and the channel variation state indication value; transmitting data to the UE in the selected downlink transmission mode. Because of extracting information from a current channel as a basis of a subsequent selection of the downlink mode, the disclosure can greatly improve a resource utilization ratio of a system and realize a better wireless transmission effect.

Abstract: A frequency offset estimation and correction method in an orthogonal frequency division multiplexing (OFDM) system is disclosed in present invention, including: obtaining a pilot frequency domain channel estimation value of a target user, and smoothing the channel estimation value in frequency domain; obtaining the link quality state of a receiver; adopting a history smoothing algorithm or a multi-branch attempt algorithm to perform frequency offset estimation and frequency offset compensation, performing frequency domain demodulation for the data for which frequency offset compensation has been performed, and outputting a link quality state parameter; and updating the link quality state of the receiver according to the link quality state parameter, determining the output value of this frequency offset estimation and outputting a history frequency offset value required by next frequency offset estimation according to the determined output value of this frequency offset estimation.

Abstract: A baseband processing method based on double sampling, including: subjecting a received signal to root raised cosine-filtering process; sampling said signal; conducting channel estimation for every user based on the sampled data; and conducting multi-user joint detection and demodulation for said data. Wherein, the step of sampling said signal includes the following steps: conducting double sampling for said signal, and the interval of the sampling being ½ chip; each chip selecting the average value of two sampling values as the sampling value of the chip; assembling the sampling value of every chip into a data stream.

Abstract: A baseband processing method based on double sampling, including: subjecting a received signal to root raised cosine-filtering process; sampling said signal; conducting channel estimation for every user based on the sampled data; and conducting multi-user joint detection and demodulation for said data. Wherein, the step of sampling said signal includes the following steps: conducting double sampling for said signal, and the interval of the sampling being ½ chip; each chip selecting the average value of two sampling values as the sampling value of the chip; assembling the sampling value of every chip into a data stream.