[2016-Spring] WNFA Lab4

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Mobile and Vehicular Network Lab

[2016-Spring] WNFA Lab4 Wireless Sensor Network

2016/5/13

Jing-Yeu Chen

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Project Scheme

7

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Device Map - CSIE 4F

SRC DST

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Device Map - CSIE 4F

DST

SRC

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● Each group will get

● 2 Zigduinos

● 2 Antenna

● 2 USB Line

● We have placed a set at 4F for testing

o lab4 routes reservation time slot

o Use your own 2 Zigduino for src, dst.

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What You Need to Do...

● Implement MAC protocol

● Implement Routing protocol

● Implement Ping test

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MAC Protocol

● CSMA/CA

● RTS/CTS

● Aloha

● ACK or NACK

● Error detecting (checksum / CRC)

● …

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Routing Protocol

● AODV

● DSR

● DSDV

● ...

● Ref : Routing.pdf

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Ping Tests

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Ping Tests

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Environment Installation

● Platform

o Zigduino hardware + Arduino software

● Steps :

1. Follow lab1 Zigduino+Arduino installation guide 2. Download ZigduinoRadiolibrary on course website

(If you encounter compile error in your Mac, try this version of ZigduinoRadio library)

3. Move ZigduinoRadio directory to

PATHWHEREARDUINOINSTALLED/Arduino/libraries (for Window)

~/Document/Arduino/libraries (for OS X)

4. Restart Arduino Software, then you can see 2 examples through

“File -> Examples -> ZigduinoRadio”

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ZigduinoRadio

● Arduino library

o Allow users using Zigduino's built-in 2.4 GHz radio transceiver easily, simple API for radio propogation

● Examples

o ZigduinoRadioExample

o SpectrumAnalyzer

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HelloWorld

• Compile and upload ZigduinoRadioExample for both Zigduino board

• ModifyNODE_ID(line10)and receiver address (line60) pkt_Tx(addr,teststr)

– EX

• Board 1 : NODE_ID 0x0001, pkt_Tx(0x0002, teststr)

• Board 2:NODE_ID 0x0002, pkt_Tx(0x0001, teststr)

• Then you will see the transmitting and receiving messages between them

– Take Board 1’Serial Terminal as an example

---

| TxDone: 0 (OK) |

| |

| Rx: ...TT 2.... |

| LQI: 255, RSSI: -37 dBm, ED: -90 dBm |

| |

| ca fail with rssi = -87 |

| |

| TxDone: 1 NO ACK |

| |

| TxDone: 0 (OK) |

| |

| Rx: ...TT 2.... |

| LQI: 255, RSSI: -37 dBm, ED: -90 dBm |

| |

---

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Functions You Should Know

● 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

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API - Serial Port Functions

● Use Tools -> Serial Monitor

○ Zigduino reset itself when 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()

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API - About Packet TX

● uint8_t pkt_Tx(uint16_t addr, uint8_t* msg)

o In ZigduinoRadioExample.pde

o A simple packet transmit function.

o Feel free to modify it.

o Set addr 0xffff for broadcast.

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API - About Packet TX

● ZigduinoRadio.attachTxDone(void(*funct)(radio_tx_done_t))

● onXmitDone(radio_tx_done_t x)

o Register a handler

o Called after a packet delivery.

o You should check tx status in that handler.

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API - About Packet RX

● 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 RxBuffer, then set RX_available.

o Use has_RX() to check if got packet

o uint8_t fcs_failed : a variable indicates incorrect packet

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API - About Packet TX/RX

● The whole process :

o TX :

 set TX_available=1  need_TX()  pkt_Tx()  Fill payload  Carrier Sense  txFrame() 

onXmitDone()  Finished when receiving HW ACK ,or retransmitting until > retry times)

o RX :

 (Hardware and pkt_Rx() will automatically run and send HW ACK) Use has_RX() to Check

RX_available==1 or not Data is in RxBuffer

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API - About Protocol, Settings (p.1)

● ZigduinoRadio.begin(channel_t chan, uint8_t* frameHeader)

● ZigduinoRadio.setChannel(channel_t chan)

o Initilizer, 11 <= channel <= 26.

o You can see correspond frequency list in

SpectrumAnalyzer.pde (the other example).

o Header must follow the IEEE802.15.4 standard.

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IEEE802.15.4 Header

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API - About Protocol, Settings (p.2)

● STATE_TX / STATE_TXAUTO / STATE_RX / STATE_RXAUTO^.

o STATE_TXAUTO requires an ACK or return with TX_NO_ACK.

o STATE_RXAUTO implements destination address check, hardware ACK, but no FCS (one kind of error detecting code).

o Zigduino sends ACK once the packet passed dst addr check .

o We strongly recommend you using both STATE_TXAUTO and STATE_RXAUTO, and paired with original/your SW error detection(FCS).

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API - About Protocol, Settings (p.3)

● 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

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API - About Protocol, Settings (p.4)

● 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 in ZigduinoRadioExample.pde, feel free to modify it

 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 retransmitting latest packet.

o …...

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API - About Protocol, Settings (p.5)

● ZigduinoRadio.getRssiNow()

● ZigduinoRadio::doCca()

o for RSSI and carrier sense

o Should add^“ZigduinoRadio.setParam(phyCCAMode, (uint8_t)3);” in setup().

o You can implement CSMA using these function

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● The hardware FCS

o Usually wrong. Suggest you do it by yourself.

o EX. 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.)

API - Problems

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● The software ACK

o Usually wrong. Please do not use Software ACK (set TX_SOFT_ACK as 0 instead of 1)

o Just use Hardware ACK and design your own algorithm to detect packet error

API - Problems

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Ping Tests

● Write your own ping()

● What we focus on :

o 1. Average RTT (round-trip time)

o 2. Ping success rate (we’ll ping 100 times)

o 3. the route this pkt has passed through

● Calculate and print them in your code

o show above information during pinging

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Calculate Consumed Time

Use millis() to get the system time

unsigned long ts1, ts2;

void loop(){

ts1 = millis();

my_ping();

ts2 = millis();

serial.println(ts2 - ts1);

}

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Review - all you have to do (1)

● 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 …...

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Review - all you have to do (2)

● Routing table - the algorithm

o “reset” packet (clear table quickly, 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 …...

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Review - all you have to do (3)

● The ping test

o packet design (sequence number, get route, ping period)

o timing to rebuild path ? o calculate time

o whole I/O design

o reset routing table o start ping

o print time+route+success_rate

● Tips

o Use LED to debug !!!

o Note the “reset” button on Zigduino board

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GRADE

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Grade

• Demo-6/7(Tues.)

– Please register the Demo Slot. And come to CSIE R424 at that time.

• Deadline:6/7(Tues.) 23:59 email to wn@csie.ntu.edu.tw

– Email subject:[WN]lab4_teamXX – [WN]lab4_teamXX.zip

• Source code and Modified Library Files (ex ZigduinoRadio.ino)

• Report(pdf)

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Grade

• Demo - the ping test (70%)

– 40% : base line, a success ping

– 10% : average RTT, get by ranking

– 10% : success rate (100 pings, 0.1% for each sec) – 10% : path rebuild after removing 1 node

• Report (20%)

– Describe what you have done, why choosing this way, and problems encountered

• Peer Review (10%)

• Bonus (5%)

– any other things you have done

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• Contact to TAs :

– facebook

https://www.facebook.com/groups/wn15spring/

– Email : wn@csie.ntu.edu.tw

– Office hour : Tues. 13:20~14:10@ CSIE R424

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Reference

● 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 https://en.wikipedia.org/wiki/Frame_check_sequ ence

o Checksum

o http://en.wikipedia.org/wiki/Checksum

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