Communication system which establishes communication sessions based on unit ID codes to avoid transmission conflicts

• US 5,541,928 A
• Filed: 11/02/1994
• Issued: 07/30/1996
• Est. Priority Date: 11/02/1993
• Status: Expired due to Term

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Toyama, Kazumasa, Kobayashi, Nakaba, Nagura, Michinaga
• Primary Examiner(s): Safourek, Benedict V.
• Assistant Examiner(s): Jung, Min
• Application Number:
  US08/334,329
• Time in Patent Office: 636 Days
• Field of Search: 370/95.1, 370/98, 455/33.1, 455/54.1, 455/54.2
• US Class Current: 340/10.31
• CPC Class Codes: G01S 13/765 with exchange of information between interrogator and responder
• CPC Class Codes: G01S 13/78 discriminating between different kinds of targets, e.g. IFF-radar, i.e. identification of friend or foe G01S13/75, G01S13/79 take precedence
• CPC Class Codes: G06K 17/0022 arrangements or provisious for transferring data to distant stations, e.g. from a sensing device "transfer between computer elements G06F13/00 "; data-transmission H04L
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10039 interrogator driven, i.e. synchronous
• CPC Class Codes: G07B 15/063 using wireless information transmission between the vehicle and a fixed station identification of vehicles G08G
• CPC Class Codes: G08G 1/017 identifying vehicles G08G1/015, G08G1/054 take precedence

Abstract

A communication system between a host station and a plurality of substations eliminates the possibility of a connection failure between the host and a given substation by attempting to establish a communication session a finite number of times. The host station transmits and receives data to and from the substations and processes the data. Every time one of the substations receives a pilot command from the host station, it selects a time slot provided in the host station'"'"'s operation schedule based on digit information of the substation'"'"'s unique ID code and transmits a response signal in that time slot to the host. If the response conflicts with another substation'"'"'s response, information based on a different digit in the ID code is selected. Because the ID code is unique to the substation, a communication session will eventually be established, and the probability of a conflict with a response from another substation is reduced to zero by re-transmission by transmitting the request a finite number of times.

Claims

1. A communication system between a host station and one or more mobile substations which enter a geographical monitoring range of said host station within which said host station can communicate with said substations, each substation having a unique ID code, said system comprising:

inquiry signal transmitting means in said host station, for transmitting an inquiry signal having a predetermined period to a substation entering said .geographical monitoring range;

inquiry signal determining means in said substation, for determining whether a signal transmitted from said host station is said inquiry signal;

selection means in said substation, for counting a number of times said inquiry signal determining means determines a signal transmitted from said host station is said inquiry signal, and for selecting information corresponding to a digit of an ID code of said substation responsive to said number of counted times; and

response signal transmitting means in said substation, for transmitting a response signal containing said ID code at a time, after said selection means selects said information, corresponding to said information selected by said selection means.

2. The communication system according to claim 1, wherein:

said host station includes information requesting signal transmitting means for transmitting an information request signal for requesting information from said substation transmitting said response signal, including said ID code of said substation when said host station receives said response signal from said substation within a predetermined time; and

said substation includes

ID code determining means for determining, when said substation receives said information request signal from said host station, whether said ID code contained in said information request signal coincides with said ID code of said substation, and

information signal transmitting means for transmitting predetermined information responsive to said information request signal to said host station when said ID code is determined to be that of said substation by said ID code discriminating means.

3. A communication system between a host station and one or more mobile substations which enter a geographical monitoring range of said host station within which said host station can communicate with said substations, each substation having a unique ID code, said system comprising:

inquiry signal transmitting means in said host station, for transmitting an inquiry signal having a predetermined period to a substation entering said geographical monitoring range;

first response signal transmitting means in said substation, for selecting information in an ID code of said substation when said substation receives said inquiry signal transmitted by said inquiry signal transmitting means and for transmitting a first response signal containing said ID code at a time, after selecting said information, corresponding to said selected information;

information request signal transmitting means in said host station, for transmitting an information request signal for requesting information from said substation receiving said response signal including said ID code of said substation when said host station receives said first response signal transmitted by said first response signal transmitting means; and

second response signal transmitting means in said substation, for determining, when said substation receives said information request signal transmitted by said information request signal transmitting means, whether said ID code contained in said information request signal coincides with said ID code of said substation and when they coincide, for transmitting a second response signal to said host station.

4. A communication system between a host station and one or more mobile units which enter a geographical monitoring range of said host station within which said host station can communicate with said tags, each mobile unit including a non-contact tag having a unique ID code, said system comprising:

inquiry signal transmitting means in said host station, for transmitting an inquiry signal having a predetermined period to a non-contact tag entering said geographical monitoring range;

inquiry signal determining means in said non-contact tag, for determining whether a signal transmitted from said host station is said inquiry signal;

selection means in said non-contact tag, for counting a number of times said inquiry signal determining means determines a signal transmitted from said host station is said inquiry signal, and for selecting information corresponding to a digit of an ID code of said tag responsive to said number of counted times; and

response signal transmitting means in said non-contact tag, for selecting a time slot which is a position of time determined by dividing said predetermined period into predetermined intervals and for transmitting a response signal containing said ID code at a timing corresponding to said selected time slot.

5. A communication system between a host station and one or more substations which enter a geographical monitoring range of said host station within which said host station can communicate with said substations, each substation having a unique ID code, said system comprising:

inquiry signal transmitting means in said host station, for transmitting an inquiry signal having a predetermined period to a substation entering said geographical monitoring range;

first response signal transmitting means in said substation, for selecting information corresponding to a digit of an ID code of said substation, when said substation receives said inquiry signal transmitted by said inquiry signal transmitting means, and for transmitting a first response signal containing said ID code at a time, after selecting said information, corresponding to said selected information;

information request signal transmitting means in said host station, for transmitting an information request signal for requesting information from substation transmitting said response signal, including said ID code of said substation, when said host station receives said first response signal transmitted by said first response signal transmitting means; and

second response signal transmitting means in said substation, for transmitting a second response signal to said host station when said ID code contained in said information request signal coincides with said ID code of said substation.

6. A communication system between a host station and one or more mobile units which enter a geographical monitoring range of said host station within which said host station can communicate with said tags, each mobile unit including a non-contact tag having a unique ID code, said system comprising:

inquiry signal transmitting means in said host station, for transmitting an inquiry signal having a predetermined period to a non-contact tag entering said geographical monitoring range;

selection means in said non-contact tag, for selecting a time slot in a response period based on information corresponding to a digit of an ID code of said tag, said digit corresponding to a number of times said tag has received said inquiry signal transmitted by said inquiry signal transmitting means;

response signal transmitting means in said non-contact tag, for transmitting a response signal containing said ID code at a timing corresponding to said time slot selected by said selection means;

information request signal transmitting means in said host station, for transmitting an information request signal for requesting information from the non-contact tag, including an ID code of said tag, when said host station receives said response signal containing said ID code transmitted by said response signal transmitting means; and

information request response signal transmitting means in said non-contact tag, for transmitting an information request response signal to said host station when said non-contact tag receives said information request signal transmitted by said information request signal transmitting means and when said ID code contained in said information request signal coincides with said ID code of said non-contact tag.

7. A method of communicating between a host station and a substation, said method comprising the steps of:

transmitting an inquiry signal from said host station;

receiving said inquiry signal at said substation;

generating information based on a unique indicia assigned to said substation, responsive to a number of times said substation has received said inquiry signal; and

transmitting, after said generating step, a reply signal from said substation to said host station after a time period corresponding to said generated information has elapsed,

wherein said receiving step includes the step of incrementing a counter when said substation receives said inquiry signal; and

said generating step includes the step of selecting information at a position in said unique indicia corresponding to contents of said counter.

8. The method of claim 7, wherein said unique indicia is a multi-digit number;

and

said selecting step includes the step of choosing a digit in said multi-digit number.

9. The method of claim 8, wherein said multi-digit number is a base-ten number.

10. A method of communicating between a host station and a substation, said method comprising the steps of:

transmitting an inquiry signal from said host station;

receiving said inquiry signal at said substation;

generating information based on a unique indicia assigned to said substation, responsive to a number of times said substation has received said inquiry signal;

transmitting, after said generating step, a reply signal from said substation to said host station after a time period corresponding to said generated information has elapsed;

receiving said reply signal at said host station; and

transmitting an information request signal from said host station to said substation, said information request signal including a field containing information representative of said unique indicia.

11. The method of claim 10, further comprising the steps of:

receiving said information request signal at said substation;

comparing said information in said field to said substation'"'"'s unique indicia; and

transmitting a second response signal from said substation to said host station when said information in said field corresponds to said substation'"'"'s unique indicia.

12. A method of transmitting information from a plurality of substations, said method comprising the steps of:

receiving an inquiry signal at each of said substations;

generating, in each of said substations, information based on a unique indicia assigned to said substation, responsive to a number of times said substation has received said inquiry signal; and

transmitting, after said generating step, a reply signal from said substation to said host station after a time period corresponding to said generated information has elapsed,

wherein said receiving step includes the step of incrementing a counter when said substation receives said inquiry signal; and

said generating step includes the step of selecting information at a position in said unique indicia corresponding to contents of said counter.

13. The method of claim 12, wherein said unique indicia is a multi-digit number;

and

said selecting step includes the step of choosing a digit in said multi-digit number.

14. The method of claim 13, wherein said multi-digit number is a base-ten number.

15. A method of transmitting information from a plurality of substations, said method comprising the steps of:

receiving an inquiry signal at each of said substations;

generating, in each of said substations, information based on a unique indicia assigned to said substation, responsive to a number of times said substation has received said inquiry signal;

transmitting, after said generating step, a reply signal from said substation to said host station after a time period corresponding to said generated information has elapsed;

receiving an information request signal responsive to said response signal at said substation;

comparing information in a predetermined field in said information request signal to said substation'"'"'s unique indicia; and

transmitting a second response signal from said substation when said information in said field corresponds to said substation'"'"'s unique indicia.

16. A substation communication system in a substation for communicating with a base station, said system comprising:

receiving means for receiving communication signals;

generating means responsive to receipt of an inquiry signal by said receiving means, for generating information based on a unique indicia assigned to said substation, responsive to a number of times said substation has received said inquiry signal;

determining means for determining when a time period corresponding to said generated information has elapsed after operation of said generating means; and

transmitting means, responsive to said determining means, for transmitting a response signal when said time period has elapsed,

wherein said receiving means includes a counter counting a number of times said substation receives said inquiry signal; and

said generating means includes means for selecting information at a position in said unique indicia corresponding to contents of said counter.

17. A substation communication system in a substation for communicating with a base station, said system comprising:

receiving means for receiving communication signals;

generating means, responsive to receipt of an inquiry signal by said receiving means, for generating information based on a unique indicia assigned to said substation, responsive to a number of times said substation has received said inquiry signal;

determining means for determining when a time period corresponding to said generated information has elapsed after operation of said generating means;

transmitting means, responsive to said determining means, for transmitting a response signal when said time period has elapsed;

comparing means for comparing information in a predetermined field in an information request signal received by said receiving means to said substation'"'"'s unique indicia;

wherein

said transmitting means is further for transmitting a second response signal when said information in said field corresponds to said substation'"'"'s unique indicia.