The service based on LOCUS Corporationfs (LOCUS) positioning technology has been provided by PHS operators in Japan: DDI POCKET, Inc. (DDI POCKET) and ASTEL Corporation (ASTEL) for 6 years in Japan.

     The feature of LOCUSfs positioning technology is that the existing infrastructure as well as the terminals (Personal Stations) can be used as they are and itfs our own technology and not under the United Statesf control such as the GPS (Global Positioning System). We are hoping that our positioning technology will greatly develop in the field of social security, utility, entertainment etc. in China as well.

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     Our positioning technology used for the PHS location-based information service is called as gEnhanced Signal Strength (ESS)h using 3 dimensional (3D) maps, however, itfs also available even with 2 dimensional (2D) maps as well. The PHS is a micro-cell system and accordingly, the ESS is enough for that.

     No special PHS terminals are necessary for the ESS, however, exclusive small terminals for PHS location-based information service are also available and they are being used mainly by children and old people in Japan.

     In order to improve an accuracy of the location-based information, more CSs (Cell Stations) would be effective in general. However, it may be expensive to add more CSs only for location-based information than for required voice traffics. Then exclusive mini-antennas for location-based information called as gRadio Beaconh are provided to solve that.

     Wefd like to explain the definition of the positioning error as follows. Itfs generally accepted to express the positioning error at 67% and 95% of accumulated probability regulated by the United States FCC (Federal Communications Commission). Itfs mandatory to locate the caller within 100 meters at 67% and 300 meters at 95% each for FCCfs E-911 (Enhanced 911) wireless emergency call. Our ESS positioning technology fully meets this requirement for micro-cell systems.

     There are two typical positioning technologies other than ours, one is the TDOA (Time Difference Of Arrival) and the other is the GPS. TDOAfs problem is that a huge infrastructure investment is requited because approximately 10% more CSs and additional special equipment to each CS become necessary. An addition of the CSs may be necessary with the construction of the new buildings. In case of the GPS, loss of the satellite signals in the building or underground may sometimes cause entirely impossible positioning. The calculation of the geographic location by the GPS is also being made by the server because of its heavy processing.

     The service based on location data (LBS : Location-Based information Service) is used for locating the wandering old people, checking where the children are, other purposes such as an effective dispatch of the field servicemen or business staffs, public safety etc. Further, itfs also available in a hall or office due to its indoor positioning capability within a few meters.

     As you can see from the above, the unification of the specification would be necessary for location-based information service which is promising in various areas to make it spread economically we think. (TWGes Ad-hoc is planning to discuss this issue.)