Apparatus and method for mobile communication

• US 6,813,508 B1
• Filed: 09/28/2000
• Issued: 11/02/2004
• Est. Priority Date: 10/01/1999
• Status: Expired due to Fees

• Current Assignee: Pioneer Corporation
• Original Assignee: Pioneer Corporation
• Inventors: Kodama, Yasuteru, Yamazaki, Osamu, Inoue, Hiroto, Suzuki, Masami, Shioda, Takehiko, Nohara, Manabu, Akimoto, Takayuki, Okamura, Masahiro, Arakawa, Katsunori
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): Nguyen, Simon
• Application Number:
  US09/671,601
• Time in Patent Office: 1,496 Days
• Field of Search: 455/422, 455/425, 455/432, 455/434, 455/436, 455/437, 455/440, 455/441, 455/442, 455/456, 455/513, 455/67.1, 370/332
• US Class Current: 455/525
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data
• CPC Class Codes: H04W 36/322 by location data

Abstract

A mobile communication apparatus and method which extract surrounding base stations within a certain defined area centered at a present location of a mobile unit, carry out an arithmetic operation for obtaining a specified weighting coefficient with respect to each of the extracted surrounding base stations on the basis of a direction of each of the extracted surrounding base stations from the present location of the mobile unit and a traveling direction of the mobile unit carry out a further arithmetic operation for weighting a value of the electric field strength of a signal recieved from each of the surrounding base stations with the weighting coefficient of a corresponding surrounding base station to provide a weighted electric field strength of each of the extracted surrounding base station, and select the one base station from the extracted surrounding base stations depending on a value of the weighted electric field strength.

Claims

1. A mobile communication apparatus which selects any one of a plurality of base stations to communicate therewith, comprising:

extracting means for extracting surrounding base stations of a mobile unit within a certain defined area centered at a present location of said mobile unit; and

base station selecting means for carrying out an arithmetic operation for obtaining a specified weighting coefficient with respect to each of said extracted surrounding base stations on the basis of a direction of each of said extracted surrounding base stations from said present location of said mobile unit and a traveling direction of said mobile unit, for carrying out further arithmetic operation for weighting a value of said electric field strength of a signal received from each of said surrounding base stations with said weighting coefficient of a corresponding surrounding base station to provide a weighted electric field strength of each of said extracted surrounding base station, and for selecting said one base station from said extracted surrounding base stations depending on a value of said weighted electric field strength.

2. A mobile communication apparatus as claimed in claim 1 further comprising:

present location detecting means for detecting said present location of said mobile unit;

traveling destination inputting means for inputting a traveling destination of said mobile unit; and

traveling destination direction estimating means for estimating a traveling destination direction of said mobile unit with said present location detected by said present location detecting means and said traveling destination input to said traveling destination inputting means.

3. A mobile communication apparatus as claimed in claim 2 wherein said base station selecting means is for carrying out an arithmetic operation for:

obtaining a direction of each of said extracted surrounding base stations extracted by said extracting means from said present location and each of locations of said extracted surrounding base stations obtained by said extracting means;

carrying out a comparison of said obtained direction of each of said extracted surrounding base stations and said traveling destination direction as said traveling direction; and

obtaining said weighting coefficient for each of said extracted surrounding base stations which is provided so that said extracted surrounding stations in directions nearer said traveling destination direction are more largely weighted.

4. A mobile communication apparatus as claimed in claim 2 wherein said traveling destination direction estimating means is for carrying out an arithmetic operation for making said traveling destination direction as a direction of a vector with an initial point thereof at a point represented by data of said present location of said mobile unit detected by said present location detecting means and a terminal point thereof at a point represented by data of said destination location data obtained through said traveling destination inputting means, said traveling destination direction being defined as a destination deflection angle which is an angle between said vector and an axis of a coordinate system determined for location.

5. A mobile communication apparatus as claimed in claim 2 wherein said base station selecting means carries out an arithmetic operation for:

obtaining a direction of each of said extracted surrounding base stations as a direction of a vector with an initial point thereof at a point represented by said present location data of said mobile unit detected by said present location detecting means and a terminal point thereof at a point represented by data of a location of each of said surrounding base stations extracted by said extracting means, said direction of said extracted surrounding base station being defined as a base station deflection angle which is an angle between said vector and an axis of a coordinate system determined for location;

obtaining a difference of each of said base station deflection angles and said destination deflection angle; and

obtaining said weighting coefficient including said difference which is provided so that a base station with said difference being smaller has a higher priority of being made as a candidate of said one base station, and

provides a table of candidate base stations with a set of base station IDs and said obtained weighting coefficients.

6. A mobile communication apparatus as claimed in claim 5 wherein said base station selecting means further measures a level of an electric field strength of a radio wave of each of said surrounding base stations to find candidate surrounding base stations each transmitting a radio wave with a level of an electric field strength allowing communication including handover;

carries out an arithmetic operation of weighting a value of said measured electric field strength of each of said radio wave with said weighting coefficient with reference to said table of candidate base stations to provide a weighted electric field strength; and

selects a base station having a large value of said weighted electric field strength as said one base station.

7. A mobile communication apparatus which selects any one of a plurality of base stations to communicate therewith, comprising:

a receiving section for receiving a radio wave transmitted from a satellite at a fixed time interval, and for outputting present location data in synchronism with said time interval;

a present location storing section for storing said present location data supplied from said receiving section;

an operation section into which location information indicating a destination is input as destination data by a user;

a map information storing section for storing map information including location data of each of base stations settled in each of service areas;

a traveling direction estimating section for estimating a traveling direction in which said user is going to travel, and for outputting said estimated direction as estimation direction data; and

a candidate base station selecting section which receives said estimation direction data output from said traveling direction estimating section;

retrieves base station location data about all of said base stations in an area within a specified radius centered at the present location from said map data storing section on the basis of said present location data;

carries out an arithmetic operation for obtaining a direction of each of said base stations as a direction of a vector with an initial point thereof at a point represented by said present location data and a terminal point thereof at a point represented by a retrieved base station location data of each of said base stations, said direction of said vector being defined as a base station deflection angle which is an angle between said vector and said axis of said coordinate system;

carries out an arithmetic operation for comparing each of said obtained base station deflection angles with said destination deflection angle, for obtaining weighting coefficients each corresponding to each of said base stations and providing a higher priority of being made as a candidate of said one base station for a base station with said base station deflection angle closer to said destination deflection angle, and for weighting a value of an electric field strength of a signal received from each of surrounding base stations with said corresponding weighting coefficient to provide a weighted electric field strength for each of base stations; and

selects said one base station depending on a value of said weighted electric field strength.

8. A method for communication used in a mobile communication system which selects any one of a plurality of base stations to communicate with a mobile unit, said method comprising the steps of:

inputting a traveling destination of said mobile unit;

detecting a present location of said mobile unit at a fixed time interval;

carrying out an arithmetic operation for obtaining a weighting coefficient for each of base stations, said weighting coefficient being provided so that a base station at the shortest distance from said mobile unit in a traveling direction thereof is made as a candidate of said one base station;

carrying out an arithmetic operation for weighting a value of an electric field strength of a signal received from each of surrounding base stations with said corresponding weighting coefficient to provide a weighted electric field strength for each of base stations; and

selecting said one base station depending on a value of said weighted electric field strength.

9. A method for communication as claimed in claim 8 wherein:

a direction of said traveling destination is estimated from said present location of said mobile unit;

surrounding base stations within a specified area centered at said present location are extracted to carry out an arithmetic operation for obtaining a direction of each of said extracted surrounding base stations from the present location;

an arithmetic operation is carried out for comparing said obtained direction of each of said base stations with said direction of said traveling destination, for obtaining weighting coefficients each providing a higher priority of being made as a candidate of said one base station for a base station with said direction of said base station closer to said direction of said traveling destination, and for weighting a value of an electric field strength of a signal received from each of surrounding base stations with said corresponding weighting coefficient to provide a weighted electric field strength for each of base stations; and

a base station is selected as said one base station depending on a value of said weighted electric field strength.