1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Real use situation 2.4GHｚ in Typical Japanese Container Yards]
Date Submitted: [17 May, 2010]
Source: [Koichiro Hayashi] Company [NYK]
Address [2-3-2 Marunouchi Chiyoda-Ku Tokyo Japan]
Voice:[ ], FAX: [ ],
Re: [
Abstract: [This document has been shown the typical usage of 2.4GHz and density of ocean containers in Japanese container yards]
Purpose: [Understanding Real Usage of 2.4GHz in Japanese Container Yard]
Notice: .
Release: ..

2. Real use situation 2.4GHz in Typical Japanese Container Yards
NYK Line
Koichiro Hayashi

3. About NYK Trade name NYK Line (Nippon Yusen Kaisha Line)
Established 1885
Head office Tokyo, Japan
Gross Sales JPY 2.4 trillion (US$ 24,737　million)
*2008 Fiscal Year
Number of employees 55,975
President Yasumi Kudo
Business areas Ocean carrier
Logistics Integrator
Size of Container Fleet 99 Vessels (398, 446 TEUs)
No 1. in Japan
No 10 among Worldwide Container Operators

4. NYK’s Activities in EPCglobal
GS1/EPCglobal Chair at TLS committee
Conducted EPCglobal TLS Pilots (Phase 1 ~ Phase 3)
NYK’s Preference on RFID Technology
Open Standard
Worldwide Acceptance
Don’t interfere with Existing Systems / Installations (not limited to RFIDs)

5. NYK Container Yard in Tokyo
Transfer crane
Gantry crane
14000TEU
275000m2
900mx300m
200m
Office
Commands are sent to crane operators by using 2.4GHz WiFi network.

6. Channel problem NYK User4 User3 User1 User2 There are many WiFi users.
Usually, there are some container yards orated different company around the port. So we can not control channel plan taking account of how adjacent company.
User4
User3
NYK
User1
User2

7. Channel usage in 2.45GHz at CY
All 83.5MHz 2.4GHz bands are used.

8. Cellular model 6 cells are needed to cover with 300m radius cells.
Assuming containers are stored as same density in this yard, there are 2000 container in a cell.
2000 tags attached on containers transmit 2.5m second signal every 10 second. It means 50% Duty. If tags don’t have carrier sense, WiFi need to send retry packet, it will make slow dawn the though put.

9. Conclusion All WiFi bands are busy in Japanese yard.
It is impossible to make channel plan, because there are many WiFi user.
2.4GHz tags will make impact to present WiFi infra sericulture if it use of WiFi channel.
26th Ch of Zigbee channel is not use frequently in the port. It is no interferences with present WiFi infrastructure.