Preamble Design and Collision Resolution in a Massive Access IoT System

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

Algorithm 3 Multiple TA value capturing scheme.

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

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

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

Captured TA value for the kth device $τ^{k}$ ;

The shared sub-preamble index for the kth device $v_{s}^{k}$ ;

The dedicated sub-preamble index for the kth device $v_{d}^{k}$ ;

The location index for the kth device $μ^{k}$ ;

1:
for all $c_{s} (n_{s}) \in S_{s}$ do
2:
Calculate $d_{s} (τ_{s})$ for the received shared sub-preamble $y_{s} (n_{s})$ according to Equation (9);
3:
if $d_{s} (τ_{s}) \geq r_{t h, s}$ then
4:
Record the sub-preamble index $v_{s}$ of $c_{s} (n_{s})$ in $Υ_{s}$ ;
5:
Calculate ${\hat{τ}}_{s}^{1}, . . ., {\hat{τ}}_{s}^{θ}$ according to Equation (10), and record them in $Γ_{s}$ ;
6:
end if
7:
end for
8:
for all $μ \in {1, 2}$ do
9:
for all $c_{d} (n_{d}) \in S_{d}$ do
10:
Calculate $d_{d} (τ_{d})$ for the received dedicated sub-preamble $y_{d} (n_{d})$ according to Equation (9);
11:
if $d_{d} (τ_{d}) \geq r_{t h, d}$ then
12:
Record the sub-preamble index $v_{d}$ of $c_{d} (n_{d})$ in $Υ_{d}$ ;
13:
Calculate ${\hat{τ}}_{d}^{1}, \dots . ., {\hat{τ}}_{d}^{σ}$ according to Equation (10), and record them in $Γ_{d}$ ;
14:
end if
15:
end for
16:
end for
17:
for all ${\hat{τ}}_{s}^{k} \in Γ_{s}$ do
18:
for all ${\hat{τ}}_{d}^{k} \in Γ_{d}$ do
19:
if ${\hat{τ}}_{s}^{k} = {\hat{τ}}_{d}^{k}$ then
20:
Output $τ^{k} = {\hat{τ}}_{s}^{k}$ and the corresponding $v_{s}^{k}$ , $v_{d}^{k}$ and $μ^{k}$ ;
21:
end if
22:
end for
23:
end for