Method of addressing messages and communications system

• US 6,275,476 B1
• Filed: 02/19/1998
• Issued: 08/14/2001
• Est. Priority Date: 02/19/1998
• Status: Expired due to Term

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Wood, Clifton W. Jr.
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): HYUN, SOON D
• Application Number:
  US09/026,248
• Time in Patent Office: 1,272 Days
• Field of Search: 370/277, 370/278, 370/280, 370/281, 370/282, 370/310, 370/312, 370/314, 370/342, 370/346, 370/445, 370/447, 370/449, 342/42, 342/43, 342/44, 340/825.06, 340/825.21, 340/825.53, 340/5.5, 340/5.61, 340/5.64
• US Class Current: 370/312
• 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 7/10019 resolving collision on the communication channels between simultaneously or concurrently interrogated record carriers. collision between the communication channels used by wireless communication devices, where the solution is not particularly adapted for RFIDs or the like, H04W74/08
• CPC Class Codes: G06Q 20/24 Credit schemes, i.e. "pay after"
• CPC Class Codes: G06Q 20/26 Debit schemes, e.g. "pay now"
• CPC Class Codes: G06Q 20/3223 Realising banking transactions through M-devices
• CPC Class Codes: G07B 15/00 Arrangements or apparatus for collecting fares, tolls or entrance fees at one or more control points handling coins or valuable papers, e.g. banknotes, G07D; apparatus for vending or hiring articles or services activated by coins, credit cards, paper currency or the like G07F7/00, G07F17/00
• CPC Class Codes: H04L 61/5092 by self-assignment, e.g. picking addresses at random and testing if they are already in use
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 40/246 Connectivity information discovery
• CPC Class Codes: H04W 74/06 using polling
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02
• CPC Class Codes: H04W 76/11 Allocation or use of connection identifiers
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support

Abstract

A method of establishing wireless communications between an interrogator and individual ones of multiple wireless identification devices, the method comprising combining tree search and Aloha methods to establish communications between the interrogator and individual ones of the multiple wireless identification devices without collision. A system comprising an interrogator, and a plurality of wireless identification devices configured to communicate with the interrogator in a wireless fashion, the respective wireless identification devices having a unique identification number, the interrogator being configured to employ tree search and Aloha techniques to determine the unique identification numbers of the different wireless identification devices so as to be able to establish communications between the interrogator and individual ones of the multiple wireless identification devices without collision by multiple wireless identification devices attempting to respond to the interrogator at the same time.

Claims

1. A system comprising:

an interrogator configured to communicate to a selected one or more of a number of communications devices;

a plurality of communications devices, respective devices being configured to store unique identification numbers respectively having a first predetermined number of bits, respective devices being further configured to respectively store a second predetermined number of bits to be used for respective random values, respective devices being configured to select random values independently of random values selected by the other devices;

the interrogator being configured to define a group of random values, the group being a subset of all possible values the devices could select, and to transmit a command requesting devices having random values corresponding to any of the random values in the defined group to respond;

devices respectively being configured to, in response to receiving the command, determine if their chosen random values fall within the defined group and, if so, send a reply to the interrogator within a randomly selected time slot of a number of possible time slots, in accordance with an Aloha technique; and

, if not, not send a reply, wherein sending a reply to the interrogator comprises transmitting both the random value of the device sending the reply and the unique identification number of the device sending the reply, wherein the time slot randomly selected by a device is selected using a random number different from the random value of that device, and wherein the number of possible slots varies from one specified group to another;

the interrogator being configured to determine if a collision occurred between devices that sent a reply and, if so, to define a new, smaller, specified group; and

the interrogator being configured to send a command individually addressed to a device after communicating with a device without a collision.

2. A system in accordance with claim 1 wherein the number of possible time slots is four.

3. A system in accordance with claim 1 wherein the number of possible time slots is four, wherein the first predetermined number of bits is sixteen, and wherein the second predetermined number of bits is sixteen.