The use of LS estimation with Vector OFDM I work in Vector OFDM, but I had an issue in channel estimation in that scheme. For example, I try to use LS channel estimation but I can't get the performance back. However, in conventional OFDM, I can use that estimation straightforward. 

First, let me present the difference of VOFDM compared with OFDM, the V-OFDM scheme is presented as below figure: 



As you see, the only difference that in V-OFDM divides the data bock into vectors and then process them by vectors. 

My question is how to use channel estimation based on pilot insertion in this case ?? any channel estimator such as for example LS. I tried different inserting the pilots in similar way of that in OFDM, but I can't get the performance back !! 

Thank you
Sorry for late reply .. I was little bit busy. 

you have mistakes in your code. Although mythology is right, you have mistakes in some parameters. 

Check this paper "Low-Complexity Equalization of Orthogonal Signal-Division Multiplexing in Double-Selective Channels" Then,  Modify your code following part II in that paper. It's with details there, if you got any issue, you'd let me know. 
Regarding the channel estimation, you follow the same way of conventional OFDM scheme except for V-OFDM you use Vectors pilots instead of symbol pilots.  I means in that mentioned paper, you will have vector of size $M$ used as pilots. 

Good luck