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Browse Prior Art Database

MINIMIZING VEHICLE LOCATION DATA IN A RADIO SITE

IP.com Disclosure Number: IPCOM000007975D
Original Publication Date: 1997-Mar-01
Included in the Prior Art Database: 2002-May-09
Document File: 2 page(s) / 119K

Publishing Venue

Motorola

Related People

Andrew Fuehl: AUTHOR [+2]

Abstract

Current vehicle location methods transmit absolute geographic location data to report a radio's current location. Due to the large size of the data, it is not practical or it is wasteful of control channel capacity to send the data on the site's control chan- nel. What is needed is a means to encode and com- press the location data in a method such that it becomes practical to transmit the data on the site's control channel.

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m MOTOROLA

V Technical Developments

MINIMIZING VEHICLE LOCATION DATA IN A RADIO SITE

by Andrew Fuehl and Robert Plaza

BACKGROUND

  Current vehicle location methods transmit absolute geographic location data to report a radio's current location. Due to the large size of the data, it is not practical or it is wasteful of control channel capacity to send the data on the site's control chan- nel. What is needed is a means to encode and com- press the location data in a method such that it becomes practical to transmit the data on the site's control channel.

SOLUTION

  The idea presented in this document utilizes data periodically broadcast on the site's outbound control channel. The data indicates the absolute geographic location coordinates of a reference point which is located either within the coverage area of the radio site or a relatively short distance from the coverage area. This information will be received and utilized by the radios within the site.

  On the radio site's control channel, both inbound and outbound, geographic location infor- mation will be provided as an offset from the refer- ence point broadcast on the outbound channel. The absolute value of any offset value can then be calcu- lated using the previously received reference point

coordinates. Since the maximum coverage area of a radio site is limited, the maximum offset within the coverage area from the reference point is also limit- ed. A limited sized offset value will be of smaller data size then an absolute value. The smaller sized value will he easier to handle and quicker to trans- mit on the site's control channel.

  A second idea presented in this document also utilizes data periodically broadcast on the outbound control channel. The data indicates the resolution of

all other geographic data transmitted both inbound and outbound on the site. The ability to adjust the data resolution provides a means to optimize the available transmittable data size to meet the varied size coverage area of different sized radio sites. The resolution will be chosen such that the highest pos- sible or most desired resolution will be used and yet limit the size of the offset data to fit within the allo- cated transmittable size.

  The ability to transmit the reference point and resolution values on the radio site allows radios to automatically adjust values while roaming between sites and without having to be preprogrammed with information for all possible sites.

EXAMPLE

  As an example, the absolute location of the site's base station antenna would be assigned as the reference point of the site. This value would be periodically transmitted on the ou...