Architecture of iMode Matthew Caesar 4/3/02

What is iMode? Goal: Easily enjoy Internet services on mobile phone Overlay on top of DoPa packet network Subscriber: New, advanced services on mobile device Operator: A way to attract new users and increase revenue Users charged on per-packet basis (~0.22 cents/128byte) Payment collection for third-party information providers

Statistics iMode a huge success Today, 80% of world’s wireless Internet users are in Japan (12.5% in Korea, 5% in Europe, 1% in USA)  2% of world’s population is in Japan Zero to 26M subscribers in 2.5 years, 50K more per day 1,000 official sites; 30,000 voluntary sites Early deployment Packet network launch 1997 iMode launch > Lots of time to experiment and learn

Goals Stick to telephone Enjoy Internet without bulky, slow PDA or PC Easy to use Users unaware of Internet Adapt browser to mobile device Leverage Internet technologies IP, TCP, HTTP, SSL, Java Media diversification Allow third parties to provide information

Architecture Packet Network (PDC-P) Communication Network (PDC) iMode Server Groupware Server PSTN Info. Provider HTTP/TCP/IP Leased Line Internet Info. Provider Info. Provider PC HTTP/TCP/IP

I-MAX Packet Network (PDC-P) MS BS PPM PGW M-SCP PPM BS MS IP Interne t BS: Base Station PPM: Packet Processing Module PGW: Packet Gateway Module M-PGW: Mobile Message-Packet Gateway Module M-SCP: Mobile Service Control Point I-MAX: Interface-Mobile Access Exchanges I-MAX M-PGW I-MAX iMode Server

Functions: Internet Access Proxy Mail Storage User Management Information charging U-MAXM-MAXC-MAXW-MAXN-MAX SW I-MAX1 I-MAX8 SWRT SW F/W SW RT Leased Line ISP 1 ISP 2 IP SWRT Customer Center Itemization Center RT M-PGW To PDC-P B-MAX D-MAXSWRT Maintenance Terminal Sales Analytic Terminal Business Remote Terminal

Protocols TLP Improved efficiency in PDC-P network over TCP (uses fewer packets to save charges) Higher data packet ratio No 3-way handshake, control signals can piggyback data ALP Supports both pull (HTTP) and push style communication Direct HTTP communication between mobile phone and iMode server UITP (User Information Transfer Protocol) sends subscriber information from PDC-P network to iMode server NWMP (Network Management Protocol) performs signaling Start/end of packet communication E.g. delivery, push content notification Telephony Function HTML ALP (Application Layer Protocol) TLP (Transport Layer Protocol) PDC-PPDC MailALP (Application Layer Protocol) IP TCP iMode Server

Security SSL (adopted March 2001) End-to-end SSL(e-eSSL) with server-side authentication  Phones have pre-configured keys Client-side authentication is future work  Non-repudiation is not yet possible Can also do SSL just between IP and iMode server (s-sSSL) PDC-P network doesn’t have to be trusted Java Can run applets from IP Java Application Manager (JAM) prevents access to handset

Current and Future Services Digital Music Distribution Car Navigation System Internet/web access E-Commerce Video-calls Streaming media Java Games Schedule Management File sharing BBS Multi-party Conferencing Workflow Management Mobile TV Interactive TV Video distribution Music Distribution Mobile Banking Concert Ticket Booking Travel Service Credit Card Bill Inquiry Mobile Trading Karaoke Fortune-telling Dictionary search Restaurant guide Walking/driving/subway directions News Housing information Weather forecast Telephone directory Airline information Hotel Reservation Discount Tour Info Stock Information Cooking Recipes Club/Event Info Downloadable Characters Horse Racing Information Location Information Horoscope CAD Complex vector graphics Flash software Animated Mail Vending Machine Interface

Application Scenario: Railroad Facility Management System Japanese railroad companies use PDAs Display diagrams of wires, tracks, signals, communications Collect data and workflow management Consider using iMode phone instead Disadvantages of PDA: Too heavy, difficult to operate Low bandwidth (wired) No dynamic updates Expensive Disadvantates of iMode phone Small display size Spotty coverage (tunnels, near buildings) Low bandwidth (wireless) M. Kikuchi, Y. Yagi, “Use of iMode Cellular Phones for Facility Management System”

Hardware Demands Low Power Ics Most power consumed by power amp New applications require more power  SSL, Multimedia, Java Memory 10x larger memory required Non-volitile storage required for media downloading services LCD More colors, faster response speed => greater power drain Battery Currently 30% of unit total weight (large) H. Yazaki et. al., “Overview of Advanced iMode Mobile Phones” K. Enoki, “iMode: The Mobile Internet Service of the 21 st Century”

Comparison with WAP/WML WAP Specification for presenting and interacting with information on wireless Sites based on new WML 39% of world’s wireless internet users Usually used over circuit switched connections Services business-oriented, work-oriented Anyone can produce content, content menus iMode  Wireless internet service (could be deployed over WAP)  Sites based on HTML (cHTML)  60% of world’s wireless internet users  Usually used over packet switched connections  Services user-oriented, fun- oriented  Anyone can produce content, DoCoMo operates content menus

Recent News iMode Launch in USA via ATT wireless Expected to launch soon Stripped down service Currently being deployed in Europe by E-Plus Already deployed in Germany

References Web sites: The iMode FAQ: Official iMode Site: “Special Issue on iMode Service”, NTT DoCoMo Technical Journal, Oct “Special Article on Advanced iMode Mobile Phones,” NTT DoCoMo Technical Journal, Jun 2001 “Wired versus Wireless Security: The Internet, WAP and iMode for E- Commerce”, ACSAC 2001 “iMode: The Mobile Internet Service of the 21 st Century”, ISSCC 2001 “Learning from iMode,” IEE Review, Nov. 2001