1. Mobile and Vehicular Network Lab [2015-Fall] WNFA lab2 - JJY JJY Simulator Chang-Jung, Huang / Guan-Ting, Chen 2015/3/27

2. Mobile and Vehicular Network Lab Outline Introduction Getting started Grade 2

3. Mobile and Vehicular Network Lab INTRODUCTION 3

4. Mobile and Vehicular Network Lab What is JJY? – the call sign of a longwave time signal radio station What is the purpose of using JJY? – Used to synchronize consumer radio-controlled clocks throughout Japan with Japan Standard Time(JST) In Japan, the station broadcasts the JJY signal from two sites – The Mount Otakadoya : 40 kHz signal – The Mount Hagane : 60 kHz signal Official website – http://jjy.nict.go.jp/index-e http://jjy.nict.go.jp/index-e Reference : http://en.wikipedia.org/wiki/JJY 4

5. Mobile and Vehicular Network Lab Service area of JJY Source ： http://my.so-net.net.tw/fashions/QA-2.htm Because Taiwan is out of range, the JJY signal from Japan is weak. Is timing synchronization function of radio- controlled clocks unuseful in Taiwan? 5

6. Mobile and Vehicular Network Lab GETTING STARTED 6

7. Mobile and Vehicular Network Lab What is the purpose of lab2? – Simulating time signal by Zigduino – Synchronizing radio-controlled clocks with radio signal (time signal) Time signal standard – JJY time code  encoded JST(Japan Standard Time) – WWVB time code  encoded UTC(Universal Time Coordinated) – … 7

8. Mobile and Vehicular Network Lab Alligator clip wire Radio-controlled clock Zigduino LED(Debug) Gnd Micro USB 8

9. Mobile and Vehicular Network Lab Hardware list – Radio-controlled clock ( 電波鐘 ) x 1 (shared) – Alligator clip wire x 1 (shared) – LED x 1 (shared) – Zigduino x 1 (used in lab1) – Micro USB line x 1 (used in lab1) 9

10. Mobile and Vehicular Network Lab How to generate the JJY signal? – Duty cycle modulation, 40 kHz or 60 kHz signal – Rules : send one bit per second, a complete time code every minute 0 bits  0.8 s of full power followed by 0.2 s of reduced power 1 bits  0.5 s of full power followed by 0.5 s of reduced power Marker bits  0.2s s of full power followed by 0.8 s of reduced power – Encode Japan Standard Time(JST) using binary-coded decimal(BCD)  JJY time code Ex. 39 (in decimal)  0011 1001 (BCD) Reference : http://en.wikipedia.org/wiki/JJY 10

11. Mobile and Vehicular Network Lab t(s) power 1234 0.2 s0.5 s 0.8 s0.5 s full power reduced power marker10 1 … … Source ： http://www.hill2dot0.com/wiki/index.php?title=Image:MLG0010-carrier.jpg 11 此次 lab 的 carrier wave 可用方波 取代 sin 波，因此可選擇使用 CTC Mode 或是 PWM Mode 來產生 ( 參 考 lab1)

12. Mobile and Vehicular Network Lab JJY time code Source ： http://en.wikipedia.org/wiki/JJY 12

13. Mobile and Vehicular Network Lab WWVB – For United States – Signal transmitted from WWVB is 60 kHz carrier wave – The transmission rules and the signal format are a little different – Official website http://www.nist.gov/pml/div688/grp40/wwvb.cfm Reference : http://en.wikipedia.org/wiki/WWVB 13

14. Mobile and Vehicular Network Lab All you have to do are: – 1-1. JJY simulator (40 kHz and 60 kHz signal) – 1-2. The clock can be synchronized to the time sent by the JJY simulator – 2-1. WWVB simulator – 2-2. The clock can be synchronized to the time sent by the WWVB simulator Note: make sure that the selected transmitting station is correct – “JPN” displayed on the top right corner of the clock  receiving JJY signal – “USA” displayed on the top right corner of the clock  receiving WWVB signal – Full instructions are given in the manual 14 Reference : http://en.wikipedia.org/wiki/Radio_clock

15. Mobile and Vehicular Network Lab GRADE 15

16. Mobile and Vehicular Network Lab Grade Deadline:4/16(Thur.) 23:59 email to wn@csie.ntu.edu.tw – Email subject:[WN]lab2_teamXX – [WN]lab2_teamXX.zip source code(JJY + WWVB) report(.pdf) Demo-4/16(Thur.) – Please register the demo slot. And come to CSIE R424 at that time. http://goo.gl/ZfKIXe http://goo.gl/ZfKIXe – All you should do are : 1. Perform synchronization with specific time given by TA in JJY format 2. Perform synchronization with specific time given by TA in WWVB format Grade – JJY : 40% – WWVB : 30% – Report : describe what team members have done(in detail), and problems encountered : 20% – Peer Assessment : 10% 16

17. Mobile and Vehicular Network Lab Contact to TAs : – facebook https://www.facebook.com/groups/wn15spring/ – Email : wn@csie.ntu.edu.tw – Office hour : Thur. 16:00~17:00@ CSIE R424 17