Algorithm 5. PDACAS_Sensor_Aggregate.

Input:

Dj; BITj; biti; Sj; raw data di; keyed values $e{k}_i^j$, 1 ≤ j ≤ q

Output:

Altered Dj and BITj

Method:

1. ci = ci + 1;

2. if ci = 3

transmit Dj to the cell header CHj;

return

3. if ci = 1

3.1 for (int k = 1; k <= p; k++)

if both the kth bit of BITj and biti are 1s

$d_i=d_i-e{k}_i^j$

Set the kth bit of BITj to be 0;

else if the kth bit of biti is 1

$d_i=d_i+e{k}_i^j$

Set the kth bit of BITj to be 1;

3.2 Dj = Dj + di;

3.3 transmits Dj and BITj to the successor;

3.4 return

4. if ci = 2

4.1 for (int k = 1; k <= p; k++)

if both the kth bit of BITj and biti are 1s

Dj = Dj −  $e{k}_i^j$;

Set the kth bit of BITj to be 0;

4.2 transmits Dj and BITj to the successor;

4.3 return