Hi,
I am using the most lowest component for sending i.e CC2420transmitC, and
CC2420ReceiveC.
Problem is that it is taking too long to send and receive a message with
just 2 bytes payload and 21byte header (CC2420_SIZE).
It is taking 8ms, so if a sender has send a packet, ACK will be received in
16ms.
I thought cc2420Transmit was the lowest component, and that it should right
away send the packet without any delay. I set the radio backoff values to 0,
and disabled CCA, but still it takes too long. please if some body know then
do share that why it takes so long,,,what it there between CC2420TransmitC
and Radio that increase the transmit time ?
The theoretical transmission delay that i calculated is* 0.736 Milli
second*i.e 736micro seconds, but in reality its taking more then 8ms
which is
strange.
// Tested in Java,
int payloadLength = 2; //Example value
int CC2420_SIZE = 21; // Example value
double transmissionTimePerSecond=0;
double transmissionTimePerMilliSecond=0;
double totalBitsToSend = 0;
double totalBytesToSend = payloadLength + CC2420_SIZE ;
totalBitsToSend = totalBytesToSend * 8;
//Data rate is 250KBits/sec i;e 250 000
transmissionTimePerSecond = totalBitsToSend / 250000 ;
transmissionTimePerMilliSecond = transmissionTimePerSecond *
1000; // 1000,000 for Micro Seconds.
//transmissionTimePerMilliSecond gives me value of :*0.736
Milli Seconds and 736.0 Micro Seconds,
*
PS:
async event void RadioBackoff.requestCca(message_t *msg){
call RadioBackoff.setCca(*FALSE*);
}
async event void RadioBackoff.requestCongestionBackoff(message_t *msg){
call RadioBackoff.setCongestionBackoff(*0*);
}
async event void RadioBackoff.requestInitialBackoff(message_t *msg){
call RadioBackoff.setInitialBackoff*(0*);
}
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