[102-2] WNFA lab4 -
A Tiny Wireless Sensor Network
2017/13/12 dalalalalala
Project Scheme
Device Map - CSIE 4F
SRC
DST ● src : R412, out door
● dst : inside R435 (茶水 間 )
● register the “lab4
routes reservation time slot”
SRC
1 2 3
4
5 6
7 8
DST
● Implement MAC protocol
● Implement routing protocol
● Implement ping test
What You Need to Do...
● Platform
o Zigduino hardware + Arduino software
● Steps :
1. follow lab1 Zigduino+Arduino installation guide 2. download ZigduionoRadio library on our website 3.put ZigduionoRadio directory into
PATHWHEREARDUINOINSTALLED/Arduino/libraries
4. Restart Arduino Software, then you can see 2 examples through
“File -> Examples -> ZigduinoRadio”
Environment Installation
● An Arduino library
o is created to allow the user to easily use Zigduino's built-in 2.4 GHz radio transceiver
o simple API for radio propogation
● Examples
o ZigduinoRadioExample
o SpectrumAnalyzer
ZigduinoRadio
● CSMA/CA
● RTS/CTS
● Aloha
● ACK or not
● error detecting code (checksum / CRC)
● …
MAC Protocol
● AODV
● DSR
● DSDV
● ...
Routing Protocol
● Application layer examples :
o examples/ZigduinoRadioExample/ZigduinoRadioExample.pde o examples/SpetrumAnalyzer/SpectrumAnalyzer.pde
● For detail :
o ZigduinoRadio.cpp o ZigduinoRadio.h o radio_rfa.c
o radio.h
Functions You Should Know
● Use Tools -> Serial Monitor
○ Zigduino reset itself when plugged in, open serial monitor, or press the “reset” button.
● Serial I/O functions
○ Serial.begin(int baudrate) // default 9600
○ Serial.available()
○ Serial.read()
○ Serial.print()
○ Serial.println(uin8_t inchar)
● Zigduino has small buffer - crash if too fast I/O
○ solution : higher baudrate or call delay()
API - Serial Port Functions
● uint8_t pkt_Tx(uint16_t addr, uint8_t* msg, uint8_t pkt_len)
o In ZigduinoRadioExample.pde
o A simple packet transmit function. Feel free to read and modify it.
o Set addr 0xffff for broadcast.
o Return 1 if get ACK. (a broadcast will get 0)
API - About Packet tx/rx (p.1)
● ZigduinoRadio.attachTxDone(void (*funct) (radio_tx_done_t))
● oxXmitDone(radio_tx_done_t x)
o Register a handler which is called after a packet delivery. You should check tx status in that
handler.
o (note: We use onXmitDone() in example. The TX_CCA_FAILED isn't implemented)
API - About Packet tx/rx (p.2)
● ZigduinoRadio.attachReceiveFrame(uint8_t* (*funct)(uint8_t, uint8_t*, uint8_t, uint8_t))
● uint8_t* pkt_Rx(uint8_t len, uint8_t* frm, uint8_t lqi, uint8_t crc_fail) o pkt_Rx() is called automatically when Zigduino
got a packet. No calling by yourself.
o pkt_Rx() will put packet in RxInternal with size RxInternal_len, then set RX_available at last.
o uint8_t fcs_failed : a variable indicates incorrect packet
API - About Packet tx/rx (p.3)
● The whole process :
o TX :
run pkt_Tx()
o RX :
(Hardware and API will automatically get packets and run pkt_Rx())
Check RX_available==1 if got a packet.
Data is put in RxInternal and RxInternal_len, move them to another buffer and set
RX_available=0 for HW receiving next packet.
API - About Packet tx/rx (p.4)
● ZigduinoRadio.begin(channel_t chan, uint8_t*
frameHeader)
o Initilizer, where input 11 <= channel <= 26.
o You can see correspond frequency list in SpectrumAnalyzer.pde (the other example program).
o Header must follow the IEEE802.15.4 standard.
API - About Protocol, Settings (p.1)
IEEE802.15.4 Header
● STATE_TX / STATE_TXAUTO / STATE_RX / STATE_RXAUTO
o You can change them in ZigduinoRadio.cpp.
o STATE_TXAUTO requires an ACK or return with TX_NO_ACK.
o STATE_RXAUTO implements destnation address check,
hardware ACK, but no FCS (one kind of error detecting code).
Zigduino sends ACK once the dst addr check is passed.
o We recommend you to use STATE_TXAUTO and
STATE_RXAUTO, paired with SW error detection(FCS).
API - About Protocol, Settings (p.2)
● Error detection schemes
o checksum, CRC, FCS, ……
o Hardware FCS is broken, please ignore that
o uint16_t cal_fcs(uint8_t* frm, uint8_t len)
in ZigduinoRadioExample.pde
kind of checksum, very simple
no good in some situations
API - About Protocol, Settings (p.3)
● MAC layer design
● already in ZigduinoRadioExample.pde
o #define NODE_ID 0x0001 // node id of this node. change it with different boards o #define CHANNEL 26 // check correspond frequency in SpectrumAnalyzer o #define TX_DO_CARRIER_SENSE 1
o #define TX_SOFT_FCS 1
they are defined at top of ZigduinoRadioExample.pde, feel free to change and test them
set 0 as unused, 1 as used
change NODE_ID with different boards (used as node id)
● what you can implement
o retransmission
o error indicating packet - RX got bad packet, then tell TX to retransmit lastest packet.
o …...
API - About Protocol, Settings (p.4)
● ZigduinoRadio.getRssiNow()
● cZigduinoRadio::doCca()
o for RSSI and carrier sense
o should have “ZigduinoRadio.setParam(phyCCAMode, (uint8_t)3);” in setup(). this is for the meaning of RSSI.
o you can implement CSMA using them
API - About Protocol, Settings (p.5)
API - Problems
● The hardware FCS
o Usually wrong. You should do it yourself.
o Pad 2 bytes after data, and ignore the last 2 bytes in pkt (the original FCS part in the protocol)
o header payload(msg) myFCS FCS
● The hardware ACK
o The hw ACK have no sender information / FCS.
o RX still send ACK even if packet content error (FCS failed.)
Ping Tests
● Write your own ping()
● What we focus on :
o average RTT (round-trip time)
o ping success rate (we’ll ping 50 times)
o the route this pkt has passed through
● Calculate and print them in your code
o show them real-time once a ping is end
Ping Tests
Use millis() to get the system time
Calculate Consumed Time
unsigned long ts1, ts2;
void loop(){
ts1 = millis();
my_ping();
ts2 = millis();
serial.println(ts2 - ts1);
}
● MAC protocol
o change CHANNEL
o design carrier sense and retry machenism
modify pkt_Tx() function
random backoff time
o STATE_TX(AUTO), STATE_RX(AUTO)
use hardware ACK
modify time period waiting ACK
● add delay in ISR(TRX24_TX_END_vect) in radio_rfa.c o design error detecting code (FCS / checksum / ...)
o …...
Review - all you have to do (1)
● Routing table - the algorithm
o “reset” packet (clear table, can save time :P)
o route rebuild
o traffic estimate: packet send rate / packet loss rate
o route optimize : ETX (hop count vs. success rate)
o …...
Review - all you have to do (2)
● The ping test
o packet design (seq num, get route, ping period)
o timing to rebuild path ? o calculate time
o whole I/O design (reset routing table / start ping and print time+route)
● Tips
o Use LED to debug !!!
o Note the “reset” button on Zigduino board
Review - all you have to do (3)
● Each group will get 2 Zigduinos
● We have placed 2 sets at 4F for testing
o lab4 routes reservation time slot
o Use your own 2 Zigduino for src, dst.
● Demo
o 5/27(Tue.) or 5/29 (Thu.) @ CSIE 4F
o demo time slot reservation o We will do the ping tests.
Devices & Demo
● Demo - the ping test (75%)
o 45% : base line, a success ping
o 10% : average RTT, get by ranking
o 10% : success rate (50 pings, 0.2% for each suc)
o 10% : path rebuild after removing 1 node
● Report (25%)
o describe what you have done, why choosing this way, and problems encountered)
● Bonus (5%)
o any other things you have done)
Grade
● Deadline
o 5/29 (Thu.) 23:59
o Required documents (teamXX_lab4_v1.zip)
Report
All source code files
o Email
wn@csie.ntu.edu.tw
Deadline
● Zigduino-radio
o https://code.google.com/p/zigduino-radio
o http://www.daxia.com/bibis/upload/ZigDuino%B5%C4Arduino%D1%A7%CF%B0%B1%CA%BC%C7.640.pdf
● Error detecting code
o FCS
o http://cs.nju.edu.cn/yangxc/dcc_teach/fcs-calc.pdf
o CRC
o checksum
o http://en.wikipedia.org/wiki/Checksum
