Training-Based MIMO Systems: Part II - Improvements using a Variable Coding Rate Scheme

In this paper the channel throughput performance is addressed for MIMO systems that employ transmission of known training sequences for channel estimation. In the companion paper, it was found that systems based on superimposed pilots (SIP) suffer from poor channel estimates, since there is interfering data power present during channel estimation. By allowing channel re-estimation, this data can be utilized as additional training power, which significantly improves the channel estimates. As the channel estimates improve, a higher coding rate can successfully be applied. These variable coding rate schemes can also be applied to conventional time-multiplexed pilot schemes. However, our numerical examples show a larger performance increase in channel throughput if applied to a SIP scheme