Full Diversity Blind Signal Designs for Unique Identification of   Frequency Selective Channels
  In this paper, we develop two kinds of novel closed-form decompositions on phase shift keying (PSK) constellations by exploiting linear congruence equation theory: the one for factorizing a $pq$-PSK constellation into a product of a $p$-PSK constellation and a $q$-PSK constellation, and the other for decomposing a specific complex number into a difference of a $p$-PSK constellation and a $q$-PSK constellation. With this, we propose a simple signal design technique to blindly and uniquely identify frequency selective channels with zero-padded block transmission under noise-free environments by only using the first two block received signal vectors. Furthermore, a closed-form solution to determine the transmitted signals and the channel coefficients is obtained. In the Gaussian noise and Rayleigh fading environment, we prove that the newly proposed signaling scheme enables non-coherent full diversity for the Generalized Likelihood Ratio Test (GLRT) receiver. 
Jian-Kang Zhang and Chau Yuen