On the Capacity of Faster-than-Nyquist MIMO Transmission with CSI at the Receiver

The demand for mobile data continues to grow as more and more data intensive applications become available to end users. One of the major challenges for the fifth generation (5G) and future mobile standards will be to develop a communication scheme capable of keeping up with the increasing demand for consumer data. In this paper we consider using faster-than-Nyquist (FTN) signaling in multiple-input-multiple-output (MIMO) systems to achieve a significantly increased channel capacity. First, we present two FTN MIMO system architectures: regularly sampled FTN MIMO and orthogonalized FTN MIMO. Then, we derive discrete-time channel models of these two architectures and evaluate the corresponding channel capacity. Our simulated capacity results indicate that a greater channel capacity can be achieved by these two FTN MIMO architectures, which is larger than using either FTN or MIMO technology independently. In addition, the orthogonalized FTN MIMO system can also reduce the complexity of the analog signal chain and de-correlates the noise in the received samples. Therefore, FTN MIMO is a potential technology for future communication systems where high throughputs are required.