Evaluation of TDD Timing Detection Error Using UL and DL Received Signals in the Relay Device

A slot timing detection method as realized by a detector and a comparator in a TDD-operated RF relay device causes timing detection errors due to received signal power fluctuations caused by fading. Here, we clarify the timing detection errors by simulating such a timing detection method using the DL received signal and the UL received signal in a relay device for various fading characteristics. When the CDL-A model is used and the moving speed is 5 km/h, the timing detection error using the DL received signal exceeds $16.7\ \mu\text{sec}$, which is the OFDM symbol length, and the BER of the UE degrades significantly, while the error is within $1\ \mu\text{sec}$ using the UL signal.