Preamble Design and Collision Resolution in a Massive Access IoT System

. 2021 Jan 2;21(1):250. doi: 10.3390/s21010250

Algorithm 2 Preamble sequence reception scheme

The received preamble sequence in the gNB $y (n)$ ;

The length of the sub-preamble $L_{i}$ ;

The length of the GI $L_{g}$ ;

The length of the empty sequence $L_{0}$ ;

The sets of the local sub-preamble sequences $S_{i}$ ;

The received shared sub-preamble sequence $y_{s} (n_{s})$ ;

The received dedicated sub-preamble sequence $y_{d} (n_{d})$ ;

1:
Intercept the first $L_{s}$ elements of $y (n)$ as $y_{s} (n_{s})$ ;
2:
Divide the residual sequence in the middle and obtain two sequences with the equal length $L_{d} + L_{g}$ , i.e., ${\tilde{y}}_{d, c a n d i d a t e 1} (n_{d})$ and ${\tilde{y}}_{d, c a n d i d a t e 2} (n_{d})$ ;
3:
Remove the GI from ${\tilde{y}}_{d, c a n d i d a t e 1} (n_{d})$ to obtain $y_{d, c a n d i d a t e 1} (n_{d})$ ;
4:
Output $y_{d} (n_{d}) = y_{d, c a n d i d a t e 1} (n_{d})$ for $μ = 1$ ;
5:
Remove the GI from ${\tilde{y}}_{d, c a n d i d a t e 2} (n_{d})$ to obtain $y_{d, c a n d i d a t e 2} (n_{d})$ ;
6:
Output $y_{d} (n_{d}) = y_{d, c a n d i d a t e 2} (n_{d})$ for $μ = 2$ ;