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Bugfix and optimization: X-MAC did not properly switch the radio off after sending a packet, resulting in increased power consumption. For packets that require an ACK, we can let the radio be on in anticipation of the ACK (controlled with an WITH_ACK_OPTIMIZATION option)

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This commit is contained in:
adamdunkels 2009-03-05 19:37:52 +00:00
parent 64badeb282
commit dc7491f810
1 changed files with 24 additions and 15 deletions
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39
core/net/mac/xmac.c
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@ -28,7 +28,7 @@
*
* This file is part of the Contiki operating system.
*
* $Id: xmac.c,v 1.26 2009/03/01 20:38:57 adamdunkels Exp $
* $Id: xmac.c,v 1.27 2009/03/05 19:37:52 adamdunkels Exp $
*/
/**
@ -63,6 +63,7 @@
#define WITH_CHANNEL_CHECK 0 /* Seems to work badly when enabled */
#define WITH_TIMESYNCH 0
#define WITH_QUEUE 0
#define WITH_ACK_OPTIMIZATION 1
struct announcement_data {
uint16_t id;
@ -353,7 +354,7 @@ send_packet(void)
rtimer_clock_t t;
int strobes;
struct xmac_hdr hdr;
int got_ack = 0;
int got_strobe_ack = 0;
struct {
struct xmac_hdr hdr;
struct announcement_msg announcement;
@ -421,9 +422,9 @@ send_packet(void)
}
watchdog_stop();
got_ack = 0;
got_strobe_ack = 0;
for(strobes = 0;
got_ack == 0 &&
got_strobe_ack == 0 &&
RTIMER_CLOCK_LT(RTIMER_NOW(), t0 + xmac_config.strobe_time);
strobes++) {
@ -444,7 +445,7 @@ send_packet(void)
CPRINTF("+");
while(got_ack == 0 &&
while(got_strobe_ack == 0 &&
RTIMER_CLOCK_LT(RTIMER_NOW(), t + xmac_config.strobe_wait_time)) {
/* See if we got an ACK */
len = radio->read((uint8_t *)&strobe, sizeof(struct xmac_hdr));
@ -458,7 +459,7 @@ send_packet(void)
CPRINTF("@");
/* We got an ACK from the receiver, so we can immediately send
the packet. */
got_ack = 1;
got_strobe_ack = 1;
}
}
}
@ -466,28 +467,37 @@ send_packet(void)
/* XXX: turn off radio if we haven't heard an ACK within a
specified time interval. */
/* if(got_ack == 0) {
/* if(got_strobe_ack == 0) {
off();
while(RTIMER_CLOCK_LT(RTIMER_NOW(), t + xmac_config.strobe_wait_time));
on();
}*/
}
if(got_ack /* XXX && needs_ack */) {
/* If we have received the strobe ACK, and we are sending a packet
that will need an upper layer ACK (as signified by the
RIMEBUF_ATTR_RELIABLE packet attribute), we keep the radio on. */
if(got_strobe_ack && rimebuf_attr(RIMEBUF_ATTR_RELIABLE)) {
#if WITH_TIMETABLE
TIMETABLE_TIMESTAMP(xmac_timetable, "send got ack");
#endif
on(); /* Wait for possible ACK packet */
} else if(!is_broadcast) {
#if WITH_ACK_OPTIMIZATION
on(); /* Wait for ACK packet */
waiting_for_packet = 1;
#else /* WITH_ACK_OPTIMIZATION */
off();
#endif /* WITH_ACK_OPTIMIZATION */
} else {
#if WITH_TIMETABLE
TIMETABLE_TIMESTAMP(xmac_timetable, "send no ack received");
#endif
on(); /* shell ping don't seem to work with off() here, so we'll
off(); /* shell ping don't seem to work with off() here, so we'll
keep it on() for a while. */
}
/* Send the data packet. */
if(is_broadcast || got_ack) {
if(is_broadcast || got_strobe_ack) {
#if WITH_TIMETABLE
TIMETABLE_TIMESTAMP(xmac_timetable, "send packet");
#endif
@ -497,7 +507,7 @@ send_packet(void)
watchdog_start();
PRINTF("xmac: send (strobes=%u,len=%u,%s), done\n", strobes,
rimebuf_totlen(), got_ack ? "ack" : "no ack");
rimebuf_totlen(), got_strobe_ack ? "ack" : "no ack");
#if XMAC_CONF_COMPOWER
/* Accumulate the power consumption for the packet transmission. */
@ -566,7 +576,7 @@ read_packet(void)
rimebuf_clear();
len = radio->read(rimebuf_dataptr(), RIMEBUF_SIZE);
if(len > 0) {
rimebuf_set_datalen(len);
hdr = rimebuf_dataptr();
@ -640,7 +650,6 @@ read_packet(void)
#if XMAC_CONF_COMPOWER
/* Accumulate the power consumption for the packet reception. */
compower_accumulate(&current_packet);
/* Convert the accumulated power consumption for the received
packet to packet attributes so that the higher levels can
keep track of the amount of energy spent on receiving the