The Achievable Rate of the Training-Based MIMO Systems Over Time-Varying Fading Channels: A BCRB Perspective on Channel Tracking
Multi-Input Multi-Output (MIMO) systems have been shown to effectively increase the transmission rate when the Channel State Information (CSI) is available at the receiver. In practice, the CSI is often estimated through training symbols inserted regularly between transmitted data, e.g., in MIMO systems such as IEEE 802.11n and IEEE 802.16e. Due to the channel variations between the training intervals and the performance limitations of estimation schemes, the achievable rates of such systems are highly dependent on the Mean Squared Error (MSE) of channel estimation. For training-based MIMO systems in block fading channels, the optimal training interval has been investigated.