Frequency estimation for the downlink of the UMTS-TDD component

We propose a carrier frequency recovery scheme for the downlink of the time-division duplex (TDD) component of the Universal Mobile Telecommunications System (UMTS). The frequency estimator exploits the midamble of the common control channel and takes into account that the frequency offset allowed in the UMTS-TDD is small compared to the chip rate. Simulations are used to assess the accuracy of the proposed scheme assuming diversity reception and a frequency selective channel. It is found that good performance can be achieved with a limited computational load.