Accurate Analysis of Implicit SISO Channel Estimation Without DC Offset Using ZCZ Training Sequence

Abstract

In this letter, an accurate analysis of implicit single-input single-output (SISO) channel estimation is provided. The appropriate correlation properties of the training sequence that result in a closed form solution for the variance of the channel estimate were derived. Indeed, it was shown that only a specific zone in the autocorrelation of the training sequence needs to be equal to zero. As a result, it is now possible to find sequences that simultaneously satisfy the balance and autocorrelation property. In fact, only a special type of sequence called zero correlation zone (ZCZ) sequences have this property and therefore can be used to provide an optimal implicit channel estimation performance when the channel length is inside the zero zone. In addition, by using balanced ZCZ sequences, the harmful Direct Current (DC) offset can be directly removed. Consequently, balanced ZCZ sequences greatly simplifies the implementation of the implicit channel estimation method.