A Novel Synchronous MAC Protocol for Wireless Sensor Networks with Performance Analysis

. 2019 Dec 6;19(24):5394. doi: 10.3390/s19245394

Algorithm 1 Proposed new channel access mechanism.

Require:

N B = 0, C W = C W_{0}, B E = B E_{m i n}, R T = 0, σ = 20 s y m b o l, T_{C C A} = 8 s y m b o l

, average packet duration time

T_{D}

Ensure: Transmission success/failure.

1:
if Beacon is not received in the control channel then
2:
Wait for the beacon in the control channel;
3:
else
4:
Switch to data channel and generate a random backoff $R_{b}$ = $r a n d o m$ (0, CW) $\times σ$ duration;
5:
if $(R_{C A P}) \leq (R_{b} + T_{C C A} + T_{D})$ then
6:
Wait for next superframe and go to step 1;
7:
else
8:
Performs CCA after $R_{b}$ duration and receives signal Y during this CCA;
9:
if Channel found busy then
10:
if $C (K S_{1}, Y, p) \geq S_{t h}$ then
11:
Switch to sleep state for $T_{D} + T_{A}$ duration;
12:
else if $C (K S_{2}, Y, p) \geq S_{t h}$ then
13:
Switch to sleep state for $T_{A}$ duration;
14:
else if $C (K S_{3}, Y, p) \geq S_{t h}$ then
15:
Switch to sleep state for $R_{A}$ duration;
16:
else
17:
Switch to sleep state for $R a n d o m (0, T_{D})$ ;
18:
end if
19:
$N B = N B + 1$ , $B E = m i n (B E + 1, B E_{m i n})$ ;
20:
if $N B > M A X_{N B})$ then
21:
Channel access failure;
22:
else
23:
Go to step 4;
24:
end if
25:
else
26:
Start transmission in the data channel;
27:
if ACK is not received then
28:
$R T = R T + 1$ ;
29:
if $R T \leq M A X_{R T}$ then
30:
Go to step 4;
31:
else
32:
Transmission failure;
33:
end if
34:
end if
35:
end if
36:
end if
37:
end if