message_t* outgoing; // If I'm sending, this is my outgoing packet
bool requestAck;
bool receiving = 0; // Whether or not I think I'm receiving a packet
+ bool transmitting = 0; // Whether or not I think I'm tranmitting a packet
+ sim_time_t transmissionEndTime; // to check pending transmission
struct receive_message;
typedef struct receive_message receive_message_t;
}
double arr_estimate_from_snr(double SNR) {
- double beta1 = 1.3687;
- double beta2 = 0.9187;
- double SNR_lin = pow(10.0, SNR/10.0);
- double X = fabs(SNR_lin-beta2);
- double PSE = 0.5*erfc(beta1*sqrt(X/2));
+ double beta1 = 0.9794;
+ double beta2 = 2.3851;
+ double X = SNR-beta2;
+ double PSE = 0.5*erfc(beta1*X/sqrt(2));
double prr_hat = pow(1-PSE, 23*2);
dbg("CpmModelC,SNRLoss", "SNR is %lf, ARR is %lf\n", SNR, prr_hat);
if (prr_hat > 1)
- prr_hat = 1;
+ prr_hat = 1.1;
else if (prr_hat < 0)
- prr_hat = 0;
+ prr_hat = -0.1;
return prr_hat;
}
int shouldAckReceive(double snr) {
double prr = arr_estimate_from_snr(snr);
double coin = RandomUniform();
- if ( (prr != 0) && (prr != 1) ) {
+ if ( (prr >= 0) && (prr <= 1) ) {
if (coin < prr)
prr = 1.0;
else
}
double prr_estimate_from_snr(double SNR) {
- double beta1 = 1.3687;
- double beta2 = 0.9187;
- double SNR_lin = pow(10.0, SNR/10.0);
- double X = fabs(SNR_lin-beta2);
- double PSE = 0.5*erfc(beta1*sqrt(X/2));
+ // Based on CC2420 measurement by Kannan.
+ // The updated function below fixes the problem of non-zero PRR
+ // at very low SNR. With this function PRR is 0 for SNR <= 3.
+ double beta1 = 0.9794;
+ double beta2 = 2.3851;
+ double X = SNR-beta2;
+ double PSE = 0.5*erfc(beta1*X/sqrt(2));
double prr_hat = pow(1-PSE, 23*2);
dbg("CpmModelC,SNR", "SNR is %lf, PRR is %lf\n", SNR, prr_hat);
if (prr_hat > 1)
- prr_hat = 1;
+ prr_hat = 1.1;
else if (prr_hat < 0)
- prr_hat = 0;
+ prr_hat = -0.1;
return prr_hat;
}
bool shouldReceive(double SNR) {
double prr = prr_estimate_from_snr(SNR);
double coin = RandomUniform();
- if ( (prr != 0) && (prr != 1) ) {
+ if ( (prr >= 0) && (prr <= 1) ) {
if (coin < prr)
prr = 1.0;
else
dbg("CpmModelC,SNRLoss", "Lost packet from %i due to %i being mid-reception\n", source, sim_node());
rcv->lost = 1;
}
+ else if (transmitting && (rcv->start < transmissionEndTime) && (transmissionEndTime <= rcv->end)) {
+ dbg("CpmModelC,SNRLoss", "Lost packet from %i due to %i being mid-transmission, transmissionEndTime %llu\n", source, sim_node(), transmissionEndTime);
+ rcv->lost = 1;
+ }
else {
receiving = 1;
}
}
command void Model.putOnAirTo(int dest, message_t* msg, bool ack, sim_time_t endTime, double power, double reversePower) {
+ receive_message_t* list;
gain_entry_t* neighborEntry = sim_gain_first(sim_node());
requestAck = ack;
outgoing = msg;
+ transmissionEndTime = endTime;
dbg("CpmModelC", "Node %i transmitting to %i, finishes at %llu.\n", sim_node(), dest, endTime);
while (neighborEntry != NULL) {
int other = neighborEntry->mote;
- sim_gain_put(other, msg, endTime, ack && (other == dest), power + sim_gain_value(sim_node(), other), reversePower + sim_gain_value(other, sim_node()));
+ sim_gain_put(other, msg, endTime, ack, power + sim_gain_value(sim_node(), other), reversePower + sim_gain_value(other, sim_node()));
neighborEntry = sim_gain_next(neighborEntry);
}
+
+ list = outstandingReceptionHead;
+ while (list != NULL) {
+ list->lost = 1;
+ dbg("CpmModelC,SNRLoss", "Lost packet from %i because %i has outstanding reception, startTime %llu endTime %llu\n", list->source, sim_node(), list->start, list->end);
+ list = list->next;
+ }
}
-
+ command void Model.setPendingTransmission() {
+ transmitting = TRUE;
+ dbg("CpmModelC", "setPendingTransmission: transmitting %i @ %s\n", transmitting, sim_time_string());
+ }
+
default event void Model.receive(message_t* msg) {}