Multiuser channel estimation for SC-FDMA system with CAZAC sounding reference sequence and Instruments-in-MATLAB verification

For the 4G Single-Carrier Frequency-Division-Multiple-Access (SC-FDMA) uplink system, the CAZAC (constant amplitude zero autocorrelation) property of Zadoff-Chu sounding reference sequence (SRS) is exploited to accomplish multiuser (MU) channel estimation in this paper. First, letting each user use an appropriate circular shift of the base SRS, the MU-SC-FDMA signal model is given. Then we derive an efficient MU channel estimation (MUCE) algorithm, which needs only a pair of FFT/IFFT operation to obtain all the users' channel impulse responses. Moreover, the computer simulation results show that only a small degradation in bit error performance is incurred by MUCE. Finally, we set up a Instruments-in-MATLAB Software-Defined Radio (IM-SDR) platform to verify the feasibility of the MUCE algorithm. Real-world measurement results of a two-user experiment show that the MUCE can simultaneously and accurately estimate the two-user channel responses specified by the RF channel emulator.