Companion source code to the article:

Exploiting Constructive Interference in IEEE 802.15.4: Survey & Hands-on Tutorial. Tengfei Chang, Thomas Watteyne, Xavier Vilajosana, Pedro Henrique Gomes.

setup

local

EUI64	GoLogic	role	Tengfei	Thomas
14-15-92-00-12-e6-3b-dd	A8	sensing	COM20	COM3
14-15-92-00-12-e6-43-0f		1A	COM16	COM4
14-15-92-00-12-e6-6f-16	B1	1B	COM19	COM5
14-15-92-00-12-e6-bb-5e		2A	COM5	COM6
14-15-92-00-12-e6-b9-57	B8	2B	COM21	COM7
14-15-92-00-12-e6-79-05		sink	COM18	COM8

testbed

EUI64	log file	rank	role
14-15-92-00-16-bf-86-a0	log_116.txt		sensing node
14-15-92-00-13-b7-6e-1f	log_132.txt
14-15-92-00-16-c0-94-61	log_136.txt
14-15-92-00-16-c0-83-c9	log_139.txt
14-15-92-00-16-c0-51-43	log_142.txt
14-15-92-00-10-cf-c0-9e	log_143.txt
14-15-92-00-16-c0-57-88	log_144.txt
14-15-92-00-16-c0-6c-1b	log_145.txt
14-15-92-00-16-c0-7a-3c	log_146.txt
14-15-92-00-16-c0-68-29	log_147.txt
14-15-92-00-16-c0-59-9d	log_149.txt
14-15-92-00-10-58-20-b2	log_151.txt
14-15-92-00-16-c0-5a-de	log_153.txt
14-15-92-00-16-c0-54-60	log_154.txt
14-15-92-00-16-bf-94-44	log_157.txt
14-15-92-00-16-c0-58-a5	log_158.txt
14-15-92-00-0d-25-b6-8b	log_159.txt
14-15-92-00-13-b7-7a-ce	log_200.txt
14-15-92-00-13-b7-70-01	log_205.txt
14-15-92-00-13-ca-e4-ab	log_219.txt		sink node

light sensor calibration

• light OFF: sensor value ~80
• light ON: sensor value ~625
• recommended threshold: 400

#define

• LOCAL_SETUP
  • different short addresses for different motes
  • change forwarding rule to force multi-hop
• LIGHTPIN_ALLMOTES
  • toggle P2.3 on all motes, not just sink mote
• UART_HOP
  • when retransmitting a DATA packet, the mote prints the hop count it will send (i.e. it's own)
• ENABLE_LEDS
  • blink LEDs on all motes
• ENABLE_DEBUGPINS
  • toggle debugpins on all motes

flashflood_local	flashflood_testbed_debug	flashflood_testbed_release
LOCAL_SETUP
LIGHTPIN_ALLMOTES	LIGHTPIN_ALLMOTES
UART_HOP	UART_HOP
ENABLE_LEDS
ENABLE_DEBUGPINS

DSN contents and use

  7 6 5 4 3 2 1 0
 +-+-+-+-+-+-+-+-+
 |L| hop |  seq  |
 +-+-+-+-+-+-+-+-+

• L: state light (0=off, 1=high)
• seq: increments at each new light switch
• hop: sensing node is hop 0

local setup
                my_addr=2     my_addr=3     my_addr=4
                 my_hop=1      my_hop=2      my_hop=3
           DATA     1A------------2A------------3A        ACK
          dest=2   /      ACK           DATA      \     dest=null
           seq=1  /     dest=null     dest=4       \     seq=1
           hop=2 /       seq=1         seq=1        \    hop=4 
 my_addr=1      /        hop=2         hop=4         \        my_addr=5
  my_hop=0     /                                      \        my_hop=4  
          sensing                                     sink

----------------------------------------------------------------------------

  my_addr=0x11                                          my_addr=0x11
          sensing                                     sink
               \                                      /
         DATA   \         ACK            DATA        /    ACK
       dest=0x11 \      dest=null      dest=0x11    /   dest=null
        seq=1     \      seq=1          seq=1      /     seq=1
        hop=0      \     hop=0          hop=2     /      hop=2
                    1B------------2B------------3B
                my_addr=0x11  my_addr=0x11  my_addr=0x11

testbed setup

packet format

DATA

    0     1     2     3     4     5     6     7     8
 +-----+-----+-----+-----+-----+-----+-----+-----+-----+
 |    FCF    | DSN |   PANID   |   dest    |    CRC    |
 +-----+-----+-----+-----+-----+-----+-----+-----+-----+

ACK

    0     1     2     3     4
 +-----+-----+-----+-----+-----+
 |    FCF    | DSN |    CRC    |
 +-----+-----+-----+-----+-----+

reference power consumption

Project	explanation	raw results	average current	energy 1min run	energy 5min run
ref_radiorx	radio on rx	link	23-24 mA	146.27 J	731.35 J
ref_radioosc	radio oscillator on	link	23-24 mA	146.25 J	731.25 J
ref_radiooff_lpm0	radio off, LPM0	link	1.90 mA	17.32 J	86.60 J
ref_radiooff_lpm3	radio off, LPM3	link	1.80 mA	16.16 J	80.80 J
ref_radiooff_lpm4	radio off, LPM4	link	1.75 mA	16.29 J	81.45 J

Timer A

• 32 kHz (ACLK), continuous mode
• never stops, rolls over every ~2s

interrupt	description
CCR1 compare	Used to calibrate ~5 MHz clock speed: how many subticks in 7 ticks? Fires every 32*7 ticks (6836us), compare TBR against last value of TBR. Then value>>5 is the number of subticks in 7 ticks.
CCR2 compare	Used to trigger light sensor sampling. Fires every 100 ticks (~3050us)
overflow	enabled by default, but no action

Timer B

• 5 MHz (SMCLK), continuous mode
• never stops (TODO: needs fixing)

interrupt	description
CCR1 capture	Triggered by the SFD pin toggling, triggers an interrupt. Do nothing on rising edge (start of frame). On falling edge (end of frame), read packet and schedule data transmission, if appropriate.
CCR2 compare	Fires when it's time to forward the packet, around 213.5us after end of frame of the ACK
overflow	enabled by default, but no action

pins

pin	name	role	description
P2.3	light	lightpin	output pin on the sink node (possibly on all nodes)
P3.4	timerAisr	debugpin	high during Timer A ISR
P6.6	timerBisr	debugpin	high during Timer B ISR
P2.6	rxforme	debugpin	toggle at beginning of calibration
P3.5	sfd	debugpin	reflects status of SFD
P6.7	radio	debugpin	radio's oscillator on

leds

led	pin	name
red	P5.4
green	P5.5
blue	P5.6	light