How can I code X matrix ?

I am studing "Bajwa et al.: Compressed Channel Sensing: A New Approach to Estimating Sparse Multipath Channels." I want to make matlab code about CCS 3 in the paper.

--Matlab code--

N0 = 5; % code length
M = 1; % the num. of codes
L = 5; % maximum delay
N0tilda = N0 + L -1;

--explain--

X is an N0tilda X L(2M+1) block matrix of the form

X = [X_{-M} ..... X_{0} ..... X_{M}.

--Matlab code--

X = zeros(N0tilda,L*(2*M+1));

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Question?

How can I code X = [X_{-M} ..... X_{0} ..... X_{M}?

Here, each block Xm has dimension N0tilda x L

--Matlab code--

Xm=zeros(N0tilda,L);