Transmission method for cellular telephony mobile equipment's location data

• US 20040106413A1
• Filed: 09/29/2003
• Published: 06/03/2004
• Est. Priority Date: 03/30/2001
• Status: Active Grant

• Current Assignee: Telecom Italia S.p.A.
• Original Assignee: Telecom Italia S.p.A.
• Inventors: Sambin, Marco
• Granted Patent: US 7,110,776 B2
• Time in Patent Office: Days
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station
• CPC Class Codes: G01S 5/0054 of actual mobile position, i.e. position calculation on base station
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

Method for cellular telephony mobile equipment location data transmission, in which an application, preferably installed on the SIM card, measures the Base Transceiver Stations in the serving cell and the neighboring cells, detecting, storing and transmitting respective information to a remote Service Centre by means of SMS messages, where a processing system, applying an appropriate algorithm and a Base Transceiver Stations geographic position database, computes the geographical position of the mobile equipment. Transmission is made using a compressed format which requires a very low number of SMS messages.

Claims

1. Method for cellular telephony mobile equipment location data transmission, in which an application, preferably installed on a SIM card contained in the mobile equipment, measures the Base Transceiver Stations in the serving cell and the neighbouring cells, detecting, storing and transmitting respective information to a remote Service Centre by means of SMS messages, where a processing system, applying an appropriate algorithm and a Base Transceiver Stations geographic position database, computes the geographical position of the mobile equipment and informs the mobile equipment of said geographical position, if required, characterised in that

said application preferably installed on the SIM card generates SMS messages containing location data in compressed format, comprising specific data of each single message, specific data on the message set, specific data on measurements and specific data on the serving cell and the neighbouring cells monitored by the mobile equipment, the dimensions of some data depending on the results of the measurements made at the current instant and those obtained at an earlier time.

2. Method for cellular telephony mobile equipment location data transmission according to claim 1, characterised in that said location data in compressed format comprises:

for each message;

the current SMS message order number;

the total number of messages dedicated to location data transmission;

consequently, in the message body;

data dedicated to specific services, where relevant;

the number of said measurements;

for each measurement;

RXLEV-FULL-SERVING-CELL, i.e. the intensity of the serving cell signal;

“

Changed Tag”

, i.e. the label indicating which of the four data—

Cell ID (serving cell identification), LAC (Local Area Code), MCC (Mobile Country Code) and MNC (Mobile Network Code), pertaining to the serving cell—

have changed with respect to the previous measurement;

MCC, if “

Changed Tag”

is higher than a first value;

MNC, if “

Changed Tag”

is higher than the first value;

LAC, if “

Changed Tag”

is higher than a second value;

Serving Cell ID, if “

Changed Tag”

is higher than a third value;

the number of monitored neighbouring cells;

for each neighbouring cell;

the relative intensity of the signal computed on the bases of the previous measurement;

“

ARFCN-BSIC cache index”

, i e. the index of the ARFCN-BSIC (channel order number-identification code) pair in an appropriate memory table;

ARFCN (channel order number), if “

ARFCN-BSIC cache index”

has a first binary value;

BSIC (identification code), if “

ARFCN-BSIC cache index”

has the first binary value;

absolute intensity of the signal, if the “

neighbouring cell relative signal intensity”

has a second binary value.

3. Method for cellular telephony mobile equipment location data transmission according to claim 2, characterised in that said location data have the following binary dimensions:

current SMS message order number, 4 bits;

total number of messages, 4 bits;

data dedicated to a specific service, 1 or more bytes;

measurement order number, 1 byte;

RXLEV-FULL-SERVING-CELL, 6 bits;

“

Changed Tag”

2 bits;

MCC, 2 bytes;

MNC, 1 byte;

LAC, 2 bytes;

serving Cell ID, 2 bytes;

number of monitored neighbouring cells, 1 byte;

neighbouring cell signal relative intensity, 5 bits;

“

ARFCN-BSIC cache index”

, 3 bits;

ARFCN, 10 bits;

BSIC, 6 bits;

neighbouring cell signal absolute intensity, 8 bits.

4. Method for cellular telephony mobile equipment location data transmission according to claim 2 or 3, characterised in that whenever a new measurement is made, said application preferably installed on the SIM card checks which of the four data (Cell ID, LAC, MCC and MNC) have changed with respect to the previous measurement and consequently sets the Changed Tag value, adding only the data which have changed to the body of the SMS message.

5. Method for cellular telephony mobile equipment location data transmission according to any of claims 2 to 4, characterised in that, in order to calculate said neighbouring cell signal relative intensity, said application preferably installed on the SIM card uses a 1-byte memory table for each monitored neighbouring cell and, during SMS coding, initialises a third binary value for each item in the table and carries but the following operations after each neighbouring cell signal intensity measurement:

if the intensity of the current neighbouring cell is included in a fit binary range with respect to the intensity of the previous measurement related to the neighbouring cell in the same position, the application only transmits the difference between the intensities and updates the table with the current intensity absolute value;

otherwise the second binary value is assigned to the relative intensity, the absolute current intensity value is sent in the subsequent byte and the table is updated with the same absolute value, a similar reversed procedure being carried out on Service Centre side for decoding.

6. Method for cellular telephony mobile equipment location data transmission according to any of claims 2 to 5, characterised in that said application preferably installed on the SIM card uses a table formed by pairs of ARFCN-BSIC values which are filled progressively as new ARFCN-BSIC pair values are encountered to obtain said “

ARFCN-BSIC cache index”

, and

if a value present in the table is encountered, the ARFCN-BSIC pair line order number or index containing the encountered value is used instead of the value itself,

if an ARFCN-BSIC value which is not present in the table is encountered and the table is fu the new value will be written over the oldest, according to FIFO mode, while, if the table is not full, “

ARFCN-BSIC cache index”

is set to the first binary value and the real value is added in the subsequent bytes, whereby adding the new value in the table,

a similar reversed procedure being carried out on Service Centre side for decoding.