Telecommun Syst DOI 10.1007/s11235-011-9480-x Performance evaluations of channel estimations in IEEE 802.11p environments Chi-Sheng Lin · Che-Kang Sun · Jia-Chin Lin · Bo-Chiuan Chen © Springer Science+Business Media, LLC 2011 Abstract A time-domain (TD) channel estimation (CE) technique is proposed in this paper to enhance the CE per- formance of IEEE 802.11p standards in cases when the pilot density is insufficient to accurately estimate channel states in rich-scattering environments. This technique is based on a least squares (LS) algorithm and assisted from Zadoff-Chu (ZC) sequences arranged into the symbol prefix and training preambles. The channel conditions tested in this paper were comprehensively simulated in urban, suburb and express- way scenarios. Keywords Channel estimation · Dedicated short range communication (DSRC) · Intelligent transportation system (ITS) · IEEE 802.11p · Pseudo random postfix OFDM (PRP-OFDM) · Least squares (LS) Acronyms AGC automatic gain control ASTM American Society for Testing and Materials AWGN Additive White Gaussian Noise BER bit-error rate C.-S. Lin ( ) · C.-K. Sun · J.-C. Lin Department of Communication Engineering, National Central University, 300, Jhongda Rd., Jhongli City, Taoyuan County 32001, Taiwan, ROC e-mail: esalin@ieee.org C.-K. Sun e-mail: 975203003@cc.ncu.edu.tw J.-C. Lin e-mail: jiachin@ieee.org B.-C. Chen Automotive Research and Testing Center, 6, Lugong S. 7th Rd., Lugang, Changhua County 50544, Taiwan, ROC e-mail: blissdom529@artc.org.tw CE channel estimation CIR channel impulse response CP cyclic prefix DFT discrete Fourier transform DSRC Dedicated Short Range Communication FCC Federal Communications Commission FD frequency domain I2V infrastructure-to-vehicle IBI inter-block interference ICI inter-carrier interference IDFT inverse discrete Fourier transform ISI inter-symbol interference ITS Intelligent Transportation System LOS line-of-sight LS least squares NLOS non-line-of-sight OFDM orthogonal frequency division multiplexing OLA overlap-add PHY physical-layer PRP pseudo random postfix rms root-mean-square SIC self-Interference cancellation TD time domain TDLE time domain linear extrapolation TDLSE time domain least squares estimation V2I vehicle-to-infrastructure WAVE Wireless Access in Vehicular Environments ZC sequence Zadoff-Chu sequences ZP zero-padding 1 Introduction IEEE 802.11p is a popular standard used for Dedicated Short Range Communication (DSRC) among vehicles.