Communication method in RFID or remote sensor systems

• US 20050242927A1
• Filed: 04/27/2005
• Published: 11/03/2005
• Est. Priority Date: 04/28/2004
• Status: Active Grant

• Current Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Original Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Inventors: Friedrich, Ulrich
• Granted Patent: US 8,054,162 B2
• Time in Patent Office: Days
• US Class Current: 340/10.200
• 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

Abstract

A method for communicating between a control unit and a plurality of remote units located in the response area of the control unit is provided. The remote units are prompted to transmit a data sequence to the control unit upon receipt of a command sent by the control unit. The control unit transmits a control signal to the remote units substantially simultaneously with the transmission of the data sequence as a function of a communication state, such as the absence of a transmission of the data sequence by at least one remote unit or an at least partially simultaneous transmission of the data sequence by more than one remote unit. In this way, communication methods can be shortened, in particular in terms of time, without adversely affecting communication reliability.

Claims

1. A Method for communicating between a control unit and a plurality of remote units located in a response area of the control unit, the method comprising the steps of:

transmitting a command from the control unit to the remote units;

transmitting a data sequence to the control unit upon receipt of the command sent by the control unit; and

transmitting a control signal from the control unit to the remote units substantially simultaneously with the transmission of the data sequence from the remote units on a basis of a communication state, the communication state being an absence of a transmission of the data sequence by at least one of the remote units or an at least partially simultaneous transmission of the data sequence by more than one of the remote units.

2. The method according to claim 1, wherein the control signal causes an at least partially simultaneous data transmission by a plurality of the remote units to be discontinued.

3. The method according to claim 1, wherein the control signal causes the control unit to stop waiting for the data transmission by the remote units.

4. The method according to claim 1, wherein the remote units, after receiving the command and before executing the command, each transmit reliability data to the control unit.

5. The method according to claim 4, wherein the control unit transmits to the remote units a confirmation symbol and an end symbol after transmission of the reliability data.

6. The method according to claim 5, wherein at least one remote unit is excluded by the confirmation symbol from executing the command.

7. The method according to claim 1, wherein the remote units each transmit, in the data sequence, a random number that they each determined and/or additional data predetermined from a data content of the remote units.

8. The method according to claim 1, wherein the control unit waits during a predetermined time window, starting at a predetermined point in time, for the transmission of the data sequence.

9. The method according to claim 8, wherein the control unit transmits, together with the command, a maximum number of time windows intended for communication.

10. The method according to claim 8, wherein a random number specifies the predetermined time window for the transmission of the data sequence by the remote unit.

11. The method according to claim 1, wherein all of the remote units executing the command begin synchronously with a first transmission of the data sequence.

12. The method according to claim 10, wherein the remote units whose random number corresponds to the time window of a common, first transmission, determine a new random number.

13. The method according to claim 7, wherein the transmission of the data sequence is terminated by the control signal during transmission of the random number.

14. The method according to claim 13, wherein a remote unit whose transmission has been terminated determines a new random number and then retransmit a data sequence during a corresponding time window.

15. The method according to claim 13, wherein a remote unit whose transmission has been terminated is excluded from executing the command until the transmission of a new command by the control unit.

16. The method according to claim 8, wherein, in the event that data transfer is absent during the predetermined time window, the method is substantially immediately continued with a next time window.

17. The method according to claim 7, wherein a length of the additional data is controlled by the control unit.

18. The method according to claim 7, wherein the transmission of the data sequence is terminated by the control signal during or after transmission of the additional data.

19. The method according to claim 18, wherein, after terminating the transmission, the control unit transmits an additional control symbol.

20. The method according to claim 19, wherein, on the basis of the additional control symbol:

a) the transmission of the additional data is continued with a next data content of the remote unit;

or

b) the transmission of the last data content of the remote unit is repeated;

or

c) the transmission of the additional data is completely terminated, at least for the remote unit in question and for a current time step.

21. The method according to claim 20, wherein, in the event of step c), reliability data are then transmitted from the remote unit to the control unit, wherein the control unit:

c1) checks the reliability data and in the event of a negative result transmits at least a first acknowledgement symbol, whereupon the remote unit is labeled as not identified;

or

c2) checks the reliability data and in the event of a positive result transmits at least a second acknowledgement symbol, whereupon the remote unit is labeled as identified and is muted;

or

c3) terminates the transmission of the reliability data by means of an end symbol, whereupon the remote unit is labeled as identified and awaits a new command.

22. The method according to claim 21, wherein, in the event of steps c1) and c2), the control unit subsequently transmits a time window control signal to begin a new time window.

23. The method according to claim 21, wherein, in the event of step c3), the control unit terminates a new command that is to be transmitted by an end symbol and then transmits a time window control signal to begin a new time window.

24. The method according to claim 23, wherein the remote unit is muted.

25. The method according to claim 22, wherein the control unit transmits an unmodulated carrier signal, which is recognized by the remote unit as the time window signal after passage of a reference time period.

26. The method according to claim 1, wherein, after termination of the transmission of the data sequence, reliability data on at least a part of transmitted data are transmitted from the remote unit to the control unit and are checked in the control unit, and wherein the control unit subsequently transmits to the remote unit the control signal on the basis of a result of the check, and wherein on the basis of the control signal the remote unit is labeled either as identified or as not identified.

27. The method according to claim 1, wherein the control unit is a base station and the remote units are a plurality of tags or remote sensor systems in an RFID system.