/**
* <br>
* In the first round,</br> <br>
* In the paper the server is supposed to ask sensors for uncoded data.</br> <br>
* We sent the maximum number of bits: 63 bits = "111111"</br> <br>
* Sensor will encode in IEEE double format</br> <br>
* Calculates the i (number of requested bits), as given in the paper</br>
*/
@Override
public String sendRequest(int sensor_id) {
if (is_first_round[sensor_id] || sensor_id == 0 || round_number < M) {
requested_bits[sensor_id] = maximum_number_of_bits_askable;
return "111111";
}
double delta = code_book.getD();
int i =
(int)
Math.ceil(
(0.5
* (Math.log((sigma[sensor_id] * sigma[sensor_id]) / (delta * delta * P_e))
/ Math.log(2.0)))
+ 1);
i = Math.min(i, maximum_number_of_bits_askable); // request not more that 63 bits
i = Math.max(0, i); // request no less than 0 bits
requested_bits[sensor_id] = i;
String bit_string =
tools.pad0ToFront(
Integer.toBinaryString(i),
bits_needed_to_represent_maximum_askable); // pad it to make length 6
return tools.reverse(bit_string);
}
@Override
public boolean receiveData(String data, int id) {
if (id != 0
&& round_number >= K
&& data.length() != requested_bits[id] + 1
&& data.length() != 0) {
return false;
}
if (!is_first_round[id] && id != 0 && !obtained_sensor_reading[0]) {
return false;
}
// first_reading / first sensor everybody is un-coded, and is assumed to be correct
if (round_number < M || is_first_round[id] || id == 0) {
is_first_round[id] = false;
current_sensor_readings[id] = tools.binaryToDouble(data);
obtained_sensor_reading[id] = true;
} else {
current_sensor_readings[id] = code_book.getDecodedValue(current_sensor_readings[0], data);
obtained_sensor_reading[id] = true;
}
// calculate Y, prediction values, only after M readings
if (round_number >= (M - 1)) {
double temp = current_sensor_readings[id];
updatePastReadings(temp, id);
this.updateInputData(id);
this.trainNeuralNets(id);
this.calculatePrediction(id);
this.updateVarianceOfPrediction(id);
} else {
double temp_value = current_sensor_readings[id];
past_sensor_readings[id][M - round_number - 1] = temp_value;
}
diff[id] = current_sensor_readings[id] - predicted_sensor_readings[id][0];
boolean all_received = true;
for (int i = 0; i < number_of_sensors; i++) {
if (!obtained_sensor_reading[i]) {
all_received = false;
break;
}
}
if (all_received) {
Arrays.fill(obtained_sensor_reading, false);
round_number++;
double average = 0.0;
for (int i = 0; i < number_of_sensors; i++) {
average += Math.abs(diff[i]);
}
// System.out.println("Total prediction error: "+average);
}
return true; // received the data
}