Contactless communication system and data carrier used for the same

• US 7,307,964 B2
• Filed: 10/22/2002
• Issued: 12/11/2007
• Est. Priority Date: 11/09/2001
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Nakashima, Shota, Nakai, Yuichiro
• Primary Examiner(s): Pezzlo, John
• Application Number:
  US10/274,913
• Publication Number:
  US 20030091005A1
• Time in Patent Office: 1,876 Days
• Field of Search: 370/278, 370/282, 370/328, 370/329, 370/336, 370/337, 370/347, 370/442, 370/252, 375220-222
• US Class Current: 370/278
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• 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

Abstract

To provide a contactless communication system that can reduce a time required to complete an identification of all data carriers that exist around a reader/writer and thus attempt to speed up its processing. According to the contactless communication system, multiple data carriers detect a response requesting command from an access device and send back an individual response signal for one-bit information to the access device at a time that is ordered based on a portion of each carrier'"'"'s identification information, and the access device monitors individual slots for the response signals and determines that detection of the presence of data carriers is completed when it has obtained individual signals from the data carriers, thereby reducing the time required to complete the identification of all data carriers.

Claims

1. A contactless communication system, comprising a plurality of data carriers, and an access device for accessing said data carriers, wherein

each of said data carriers detects a response requesting command from said access device and sends back an individual response signal for one-bit information at a time ordered based on a portion of its identification information of said data carrier, and

said access device monitors individual slots of said response signals and determines that detection of the presence of data carriers is completed when the access device has obtained individual signals from said data carriers.

3. The contactless communication system according to claim 1, wherein

said access device monitors individual slots of said response signals and determines that detection of the presence of data carriers is completed when the access device has obtained individual signals from said plurality of data carriers, transmits a response halt request added with a new identification number that is generated based on information on a slot time for a response to a data carrier whose presence has been detected, and transmits the response request again to a data carrier whose presence has not yet been detected, and

said data carriers detect said response halt request and store said identification number.

4. The data carrier for use in a contactless communication system according to claim 3, wherein

said data carrier detects a response requesting command from an access device and transmits an individual signal for one-bit information at a time ordered based on a portion of identification information of said data carrier, and detects a response halt request added with a new identification number that is transmitted by said access device to a data carrier whose presence has been recognized with the individual signal and stores said new identification number.

2. A data carrier for use in a contactless communication system, wherein

a response requesting command from an access device is detected and an individual signal for one-bit information at a time ordered based on a portion of the data carrier'"'"'s identification information is transmitted.

5. A communication method for a contactless communication system, wherein an access device identifies and communicates with a plurality of data carriers in a communication area, comprising:

detecting a response requesting command from said access device in each of said data carriers and sending back to said access devices an individual response signal for one-bit information at a time ordered based on a portion of its identification information of said data carriers; and

monitoring individual slots of said response signals at said access device and determining that detection of the presence of data carriers is completed when the access device has obtained individual signals from each of said plurality of data carriers.

6. The communication method for a contactless communication system according to claim 5, wherein

said access device transmits a response halt request that is added with a new identification number generated based on information on slot time for a response to a data carrier whose presence has been detected, and transmits said response request again to a data carrier whose presence has not been detected, and

each of said data carriers detects said response halt request and stores said identification number.