1. CDPD Service Liu ShuPing Feng Yue

2. Current Situation Of Mobile Data Communications  Circuit-switched cellular technology.  TACS, AMPS, GSM and CDMA use now.  Occupying channel during the whole connection time  Packet-switched cellular technology  Each data gram is encapsulated and sent packets individually.  Cellular Digital Packet Data technology  Same Idea as Packet-Switched.

3. What Is CDPD AAAA service? AAAA technology? AAAA network? AAAA standard?

4. History Of AMPS  CDPD calls AMPS “mum”.  AMPS, originated in 1960s, born in 1980s.  Birth Place: Bell Lab.  1983, AMPS speech service was availble in USA.  Run on 800MHz, why?  Lower for TV and FM.  Higher can not be used with that time technology.  Fundenmental success, the first wide spread public wireless, mobile, communication service and network.

5. CDPD History.  In 1992, AT&T, MGcaw, BAM, SW Bell, North Telecom, Ameritech provided 1000,000us$ each to make a fund for data service.  In 1993, the first version of standard of CDPD came into view.  In 1994, in America, the first CDPD experimental network run.  CDPD ROUND TABLE: CDPD Forum was founded on April 1994.  CS-CDPD was born latter. Circuit Switch, only run by GTE, number 1800.

6. Features Of CDPD  19.2 kbps maximum throughput. Real user data is less than 12kbps.  Uses same frequency spectrum as AMPS.  Channel hopping. Two types. Purpose is to safe higher priority voice QoS.  TCP/IP Based. Very clever. Save cost, time, more reliable, compatible.  Dedicated Channels. AMPS voice channels lose. But it is a sign….  Encryption over Airinterface like GSM.  DSMA-CD congestion control and MAC access.  Available in whole USA Now.

7. CDPD Network Components  MDBS, Mobile Data Base Station, equal to the BTS in GSM.  air interface control  radio frequency management  automatic radio hopping.  MDIS, Mobile Data Intermediate Station. It partially combines the functions of BSC and MSC in GSM.  radio exchange, setting up the radio channels.  IS, Intermediate System. CDPD is an IP based system. CDPD backbone network is construed by the IS. We can say IS is also a router.  CDPD ES. M-ES and F-ES.  External F-ES is administered by CDPD subscribers. Internal F-ES is administered by the CDPD operators. NOTE!

8. CDPD Network Service  Network Service is in term of Air Interface.  Domain Name Server. has its own web address translating mechanism. IS functions.  Subscriber Location Service. Not as accurate as GPS. Still enough.  Mobility Management Service. Each subscriber’s home MDIS tracks the her/his location.  Network Management Services.  Account Service.  Authentication Service.

9. CDPD vs. GPRS  CDPD’s real competitor is GPRS. Because of same time, same place, similar service and targeted customers.  ADV:  Standarised earlier.  Operators have already invested a lot.  In America and Asia Pacific countries, it has in born adv, because AMPS.  At intial phase of service, cost for each subscriber is lower than GPRS.  DisADV:  GPRS 171.2kbps, CDPD 19.2kbps.  GPRS has much more larger capacity than CDPD.  GPRS uses TDMA GSM, but CDPD uses the FDMA AMPS.  GPRS can offer both Con-less, and Con-orient service, but CDPD only can provide Con-less service.  GPRS supports both IPv4 and IPv6. However, the CDPD only support IPv4. Less security, and address space.

10. CDPD And GPRS Similarity  Easy to enlarge the capacity.  Small delay.  Both security is high.  GPRS: CS-1, CS-2.  CDPD: Reed Solomon.

11. Attractiveness And Problems at America  Attractiveness: Based on TCP/IP, easy to check email.  Problem1: Different competitor-operators need to provide CDPD service.  Problem2: It was too expensive. 80$ 1MB.  Problem3: Software did not run well.  Problem4: Wireless transmission problem.  But Now, most of them are not new problems.

12. Business Of CDPD In American Market  Giants: AT&T, Bell Atlantic, AT&T Wireless. Too Big. “ Trust” characteristics.  Now, CDPD is facing competition from GPRS service from same fathers even in its’ birth place.  My opinion, is because its’ rate is much slower compared with GPRS, HSCSD.

13. The CDPD Business In Latin America  Tele2000 runs CDPD service in Latin American countries. Peru, Chile….  They prefer the most economic solution.  Tele2000 runs the service jointly with AT&T in Latin America.

14. CDPD Applications  Transportation: Ambulance, dispatch system.  Public security: Policemen can access the latest database in real time to. E.g. Check suspected person, Verify identity. Check the car current status.  Remote measurement: Remote control.  Commerce. Wireless ATM. Wireless Credits Card Authentication. Mobile Payment. Adv of CDPD used in commerce field.  Implementing easily.  High speed. CDPD modem set up time is much faster than wire dial up modem. Even CDPD is 19.2kbps, wire dial up modem is 33.6kbps.  Reliable and Safety with strong encryption algorithm.  Personal use which covers the main part of the CDPD usage.

15. CDPD In Chinese Market  Development History Of CDPD In China Mainland.  CDPD In China Hong Kong.  M499.com is the only CDPD operator in Hong Kong.  Grab the gap before the 3G.  The market is not so big, but achievements.  Want to find huge local operator to do joint. I am not optimistic.  So M499.com comes to China Mainland to make money.

16. The Relation Between CDPD And Other PLMN Network In China  HSCSD’s advantage is its’ transmission of large amount data. But CDPD is not suitable for this.  It can be realized that smooth connection between CDPD and narrow band CDMA.  Mobitex is from Ericsson. It is too slow. 8Kbps raw data.  CDPD is also face the new Wi-Fi Chanllenge. Because it is much faster than CDPD.  WAP is even more technical advanced, why lost game in China.  Few content.  Too expensive, twice more expensive than CDPD.

17. CDPD License In China. No Auction No Auction

18. Impact Of WTO To CDPD Service  More open market.  Foreign capital can enter.  Reduce the telecommunication service tarriffs.  Wellcome to invest!!!

19. Current CDPD Operators In China  China Telecom. Has the position of AS&T in USA.  Shang Hai P&T Mobile Data Communication Co. Ltd.  But it seems they will not invest any more to the CDPD public service. Because our 2G systems are mainly GSM.

20. Wireless ATM Via CDPD  More and more popular in China.  Very convenient.  CDPD provides reliable, fast and safe access.  Maintenance is not very high.