CDPD Service Liu ShuPing Feng Yue

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.

What Is CDPD A service? A technology? A network? A standard?

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.

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.

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.

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!

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.

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.

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

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.

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.

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.

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.

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.

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.

CDPD License In China. No Auction

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

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.

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