Frequency Selective Pilot Arrangement for Orthogonal Wavelet Packet Modulation Systems

Orthogonal wavelet packet modulation (OWPM) is a potential technique for achieving high bit rates required wireless access. Effective channel estimation can supply channel state information (CSI) at the receiver, the knowledge of which OWPM system performance relies on. The objective of this paper is to introduce an innovative channel estimation method with unequal interval pilots for OWPM system. With consideration of the frequency domain characteristic of the wavelet packet in the same level, the time coherence influenced by carrier frequency is analyzed. Then a pilot arrangement algorithm is designed with unequal interval insertion in different subcarriers of OWPM system. And based on the temporal estimation at pilot positions performed by LS, channel parameters corresponding to the unknown data can be obtained by using linear interpolation. At last, we conduct the simulation with comparing the BERs obtained from different pilot arrangement methods for QPSK/16QAM. The results demonstrate that our methods can perform excellently in multi-path Rayleigh fading channel.