Investigations on Optimum Reference Signal Structure for Single-Carrier FDMA Radio Access in Evolved UTRA Uplink

This paper presents the optimum reference signal (RS) structure for single-carrier (SC)-FDMA radio access using discrete Fourier transform (DFT)-spread OFDM to satisfy the requirements in the Evolved UTRA uplink. The simulation results shows that the optimum fast Fourier transform (FFT) block length, i.e., data block length, is approximately 66.7 – 133.3 μsec, corresponding to the FFT length of 1024 – 2048 points assuming the sampling frequency of 15.36 Mega samples per second. Moreover, it is shown that an RS structure that comprises two RS blocks contained within the duration of a 1-msec sub-frame is the most promising candidate based on superior user throughput under low mobility conditions such as less than approximately 120 km/h and on a high degree of commonality of radio parameters such as that in the downlink, considering the fairly low applicability of 16QAM modulation under extremely high mobility conditions such as 350km/h.