US 2009/0015382 A1 · SYSTEMS AND METHODS FOR COLLISION AVOIDANCE IN A MULTIPLE RFID INTERROGATOR ENVIRONMENT

Abstract

A method for collision avoidance in a multi-reader environment comprising a plurality of Radio Frequency Identification (RFID) interrogators, the method comprises each of the plurality of interrogators entering a quiet state during which none of the interrogators transmits, each of the plurality of interrogators selecting a transmit time after the quiet period during which each of the interrogator will attempt to transmit, each of the plurality of interrogators monitoring their associated receive path, an interrogator of the plurality of interrogators transmitting an instruction during its selected transmit time indicating the beginning of a session when the interrogator does not detect data on its receive path prior to its select transmit time, the interrogator comparing its receive path to its transmit path when it transmits the instruction, the interrogator returning to the quiet state when the receive path does not match the transmit path, and the interrogator completing the session when the receive path matches the transmit path.

Claims25

Dependent claims

A method for collision avoidance in a multi-reader environment comprising a plurality of Radio Frequency Identification (RFID) interrogators, the method comprising;

each of the plurality of interrogators entering a quiet state during which none of the interrogators transmits;
each of the plurality of interrogators selecting a transmit time after the quiet period during which each of the interrogator will attempt to transmit;
each of the plurality of interrogators monitoring their associated receive path;
an interrogator of the plurality of interrogators transmitting an instruction during its selected transmit time indicting the beginning of a session when the interrogator does not detect data on its receive path prior to its select transmit time;
the interrogator comparing its receive path to its transmit path when it transmits the instruction;
the interrogator returning to the quiet state when the receive path does not match the transmit path;
and
the interrogator completing the session when the receive path matches the transmit path.

5 more elements

An RFID interrogator, comprising;

a transmit circuit configured to generate transmit data;
a receive circuit configured to decode receive data;
a collision detection circuit configured to compare the transmit data with the receive data;
a processor coupled with the transmit circuit and the receive circuit, the processor configured to execute instructions;
and
a memory coupled with the processor, the memory configured to store instructions, the instructions configured to cause the processor to:
enter a quiet state during which the processor prevent the transmit circuit from generating transmit data,
select a transmit time after the quiet period during which the interrogator will attempt to transmit data via the transmit circuit,
cause an instruction to be transmit an instruction during the selected transmit time indicating the beginning of a session when the receiver does not detect data on its receive path prior to the select transmit time,
return to the quiet state when the collision detection circuit detects that the receive path does not match the transmit path after the instruction is transmitted, and
allow the interrogator to complete the session when the collision detection circuit determines that the receive path matches the transmit path after the instruction is transmitted.

8 more elements

Dependencies are inferred from the claim text.

Systems and methods for collision avoidance in a multiple rfid interrogator environment

Life of this patent

Systems and methods for collision avoidance in a multiple rfid interrogator environment

Life of this patent

Abstract

Claims25