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A quick, initial implementation of the LPP power-saving MAC protocol (Musaloiu-E et al, IPSN 2008)

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adamdunkels 2008-05-15 08:56:29 +00:00
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2
core/net/mac/Makefile.mac
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CONTIKI_SOURCEFILES += xmac.c nullmac.c
CONTIKI_SOURCEFILES += xmac.c nullmac.c lpp.c #xmac2.c

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core/net/mac/lpp.c Normal file
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/*
* Copyright (c) 2008, Swedish Institute of Computer Science.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This file is part of the Contiki operating system.
*
* $Id: lpp.c,v 1.1 2008/05/15 08:56:29 adamdunkels Exp $
*/
/**
* \file
* Low power probing (R. Musaloiu-Elefteri, C. Liang,
* A. Terzis. Koala: Ultra-Low Power Data Retrieval in
* Wireless Sensor Networks, IPSN 2008)
*
* \author
* Adam Dunkels <adam@sics.se>
*
*
* This is an implementation of the LPP (Low-Power Probing) MAC
* protocol. LPP is a power-saving MAC protocol that works by sending
* a probe packet each time the radio is turned on. If another node
* wants to transmit a packet, it can do so after hearing the
* probe. To send a packet, the sending node turns on its radio to
* listen for probe packets.
*
*/
#include "dev/leds.h"
#include "net/rime.h"
#include "net/mac/mac.h"
#include "net/mac/lpp.h"
#include "net/rime/rimebuf.h"
#define DEBUG 0
#if DEBUG
#include <stdio.h>
#define PRINTF(...) printf(__VA_ARGS__)
#else
#define PRINTF(...)
#endif
#define TYPE_PROBE 1
#define TYPE_DATA 2
struct lpp_hdr {
uint16_t type;
rimeaddr_t sender;
rimeaddr_t receiver;
};
static const struct radio_driver *radio;
static void (* receiver_callback)(const struct mac_driver *);
static struct pt pt;
static struct ctimer timer;
static struct queuebuf *queued_packet;
#define LISTEN_TIME CLOCK_SECOND / 128
#define OFF_TIME CLOCK_SECOND / 2
#define DUMP_QUEUED_PACKET 1
/*---------------------------------------------------------------------------*/
static void
turn_radio_on(void)
{
radio->on();
leds_on(LEDS_YELLOW);
}
/*---------------------------------------------------------------------------*/
static void
turn_radio_off(void)
{
radio->off();
leds_off(LEDS_YELLOW);
}
/*---------------------------------------------------------------------------*/
/**
* Send a probe packet.
*/
static void
send_probe(void)
{
struct lpp_hdr *hdr;
rimebuf_clear();
hdr = rimebuf_dataptr();
rimebuf_set_datalen(sizeof(struct lpp_hdr));
rimeaddr_copy(&hdr->sender, &rimeaddr_node_addr);
rimeaddr_copy(&hdr->receiver, rimebuf_addr(RIMEBUF_ADDR_RECEIVER));
hdr->type = TYPE_PROBE;
PRINTF("Sending probe\n");
radio->send(rimebuf_hdrptr(), rimebuf_totlen());
}
/*---------------------------------------------------------------------------*/
/**
* Duty cycle the radio. The protothread is driven by a ctimer that is
* initiated in the lpp_init() function.
*/
static int
dutycycle(void *ptr)
{
struct ctimer *t = ptr;
PT_BEGIN(&pt);
while(1) {
if(queued_packet != NULL) {
/* We are currently sending a packet so we should keep the radio
turned on and not send any probes at this point. */
ctimer_set(t, OFF_TIME * 2, dutycycle, t);
PT_YIELD(&pt);
queuebuf_free(queued_packet);
queued_packet = NULL;
PRINTF("Removing old packet\n");
}
turn_radio_on();
send_probe();
ctimer_set(t, LISTEN_TIME, dutycycle, t);
PT_YIELD(&pt);
turn_radio_off();
/* There is a bit of randomness here right now to avoid collisions
due to synchronization effects. Not sure how needed it is
though. XXX */
ctimer_set(t, OFF_TIME / 2 + (random_rand() % OFF_TIME / 2), dutycycle, t);
PT_YIELD(&pt);
}
PT_END(&pt);
}
/*---------------------------------------------------------------------------*/
/**
*
* Send a packet. This function builds a complete packet with an LPP
* header and queues the packet. When a probe is heard (in the
* read_packet() function), and the sender of the probe matches the
* receiver of the queued packet, the queued packet is sent.
*
* ACK packets are treated differently from other packets: if a node
* sends a packet that it expects to be ACKed, the sending node keeps
* its radio on for some time after sending its packet. So we do not
* need to wait for a probe packet: we just transmit the ACK packet
* immediately.
*
*/
static int
send_packet(void)
{
struct lpp_hdr *hdr;
rimebuf_hdralloc(sizeof(struct lpp_hdr));
hdr = rimebuf_hdrptr();
rimeaddr_copy(&hdr->sender, &rimeaddr_node_addr);
rimeaddr_copy(&hdr->receiver, rimebuf_addr(RIMEBUF_ADDR_RECEIVER));
hdr->type = TYPE_DATA;
rimebuf_compact();
PRINTF("queueing packet type %d\n", hdr->type);
if(rimebuf_attr_isset(RIMEBUF_ATTR_PACKET_TYPE) &&
rimebuf_attr(RIMEBUF_ATTR_PACKET_TYPE) == RIMEBUF_ATTR_PACKET_TYPE_ACK) {
/* Immediately send ACKs - we're assuming that the other node is
listening. */
/* printf("Immediately sending ACK\n");*/
return radio->send(rimebuf_hdrptr(), rimebuf_totlen());
} else {
/* If a packet is already queued, the DUMP_QUEUED_PACKET option
determines if the queued packet should be replaced with the new
packet, or if the new packet should be dropped. XXX haven't
measured the effect of this option */
#if DUMP_QUEUED_PACKET
if(queued_packet != NULL) {
queuebuf_free(queued_packet);
}
queued_packet = queuebuf_new_from_rimebuf();
#else /* DUMP_QUEUED_PACKET */
if(queued_packet == NULL) {
queued_packet = queuebuf_new_from_rimebuf();
}
#endif /* DUMP_QUEUED_PACKET */
/* Wait for a probe packet from a neighbor */
turn_radio_on();
}
return 1;
}
/*---------------------------------------------------------------------------*/
/**
* Read a packet from the underlying radio driver. If the incoming
* packet is a probe packet and the sender of the probe matches the
* destination address of the queued packet (if any), the queued packet
* is sent.
*/
static int
read_packet(void)
{
int len;
struct lpp_hdr *hdr, *qhdr;
rimebuf_clear();
len = radio->read(rimebuf_dataptr(), RIMEBUF_SIZE);
if(len > 0) {
rimebuf_set_datalen(len);
hdr = rimebuf_dataptr();
rimebuf_hdrreduce(sizeof(struct lpp_hdr));
PRINTF("got packet type %d\n", hdr->type);
if(hdr->type == TYPE_PROBE) {
if(queued_packet != NULL) {
qhdr = queuebuf_dataptr(queued_packet);
if(rimeaddr_cmp(&qhdr->receiver, &hdr->sender) ||
rimeaddr_cmp(&qhdr->receiver, &rimeaddr_null)) {
PRINTF("%d.%d: got a probe from %d.%d\n",
rimeaddr_node_addr.u8[0], rimeaddr_node_addr.u8[1],
hdr->sender.u8[0], hdr->sender.u8[1]);
radio->send(queuebuf_dataptr(queued_packet),
queuebuf_datalen(queued_packet));
queuebuf_free(queued_packet);
queued_packet = NULL;
turn_radio_on(); /* XXX Awaiting an ACK: we should check the
packet type of the queued packet to see
if it is a data packet. If not, we
should not turn the radio on. */
}
}
} else if(hdr->type == TYPE_DATA) {
PRINTF("%d.%d: got data from %d.%d\n",
rimeaddr_node_addr.u8[0], rimeaddr_node_addr.u8[1],
hdr->sender.u8[0], hdr->sender.u8[1]);
}
len = rimebuf_datalen();
}
return len;
}
/*---------------------------------------------------------------------------*/
static void
set_receive_function(void (* recv)(const struct mac_driver *))
{
receiver_callback = recv;
}
/*---------------------------------------------------------------------------*/
static int
on(void)
{
turn_radio_on();
return 1;
}
/*---------------------------------------------------------------------------*/
static int
off(int keep_radio_on)
{
if(keep_radio_on) {
turn_radio_on();
} else {
turn_radio_off();
}
return 1;
}
/*---------------------------------------------------------------------------*/
static const struct mac_driver lpp_driver = {
send_packet,
read_packet,
set_receive_function,
on,
off,
};
/*---------------------------------------------------------------------------*/
static void
input_packet(const struct radio_driver *d)
{
if(receiver_callback) {
receiver_callback(&lpp_driver);
}
}
/*---------------------------------------------------------------------------*/
const struct mac_driver *
lpp_init(const struct radio_driver *d)
{
radio = d;
radio->set_receive_function(input_packet);
ctimer_set(&timer, LISTEN_TIME, dutycycle, &timer);
return &lpp_driver;
}
/*---------------------------------------------------------------------------*/

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core/net/mac/lpp.h Normal file
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/*
* Copyright (c) 2008, Swedish Institute of Computer Science.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This file is part of the Contiki operating system.
*
* $Id: lpp.h,v 1.1 2008/05/15 08:56:29 adamdunkels Exp $
*/
/**
* \file
* Low power probing (R. Musaloiu-Elefteri, C. Liang,
* A. Terzis. Koala: Ultra-Low Power Data Retrieval in
* Wireless Sensor Networks, IPSN 2008)
*
* \author
* Adam Dunkels <adam@sics.se>
*/
#ifndef __LPP_H__
#define __LPP_H__
#include "net/mac/mac.h"
#include "dev/radio.h"
const struct mac_driver *lpp_init(const struct radio_driver *d);
#endif /* __LPP_H__ */