Method of, and apparatus for, protecting from radio frequency interference

• US 7,650,115 B2
• Filed: 03/16/2004
• Issued: 01/19/2010
• Est. Priority Date: 03/27/2003
• Status: Expired due to Fees

• Current Assignee: Uniloc 2017 LLC (SoftBank Group Corp.)
• Original Assignee: IPG Electronics 503 Limited (Coller IP Capital Limited)
• Inventors: Caldwell, Richard J., Payne, Adrian W.
• Primary Examiner(s): Anderson; Matthew D
• Assistant Examiner(s): GONZALES, APRIL GUZMAN
• Application Number:
  US10/550,337
• Publication Number:
  US 20070010206A1
• Time in Patent Office: 2,135 Days
• Field of Search: 455/63.1, 455/64, 455/67.3, 455/556, 455/422, 455/63.2, 455/67.13, 455/278.1, 455/296, 455/423, 455/425, 455/41.2, 370/686.6, 370/506, 370/825.6
• US Class Current: 455/63.1
• CPC Class Codes: H04W 48/02 Access restriction performed under specific conditions

Abstract

A method of protecting an apparatus from radio frequency interference, comprises a policing terminal (PT) detecting the presence of an interfering radio terminal (16) in the protected environment and actively rendering ineffective or terminating transmissions by the interfering radio terminal. Various options can be followed by the policing terminal (PT) including (a) attempting to become the master station of a network of which the interfering terminal is a member and instructing the members to close down or (b) failing to become the master station and transmitting interference signals for at least a selected portion, for example preamble and sync, of the duration of a data packet transmitted by the interfering station.

Claims

1. A method of protecting an apparatus from radiofrequency interference in a predetermined radio-frequency band, comprising, at a policing terminal:

detecting the presence of a radio terminal operable to generate interference in the predetermined radio-frequency band and in accordance with a first predetermined signaling protocol, wherein the signaling protocol specifies operation of a wireless local area network in which the network comprises a plurality of terminals, and wherein the protocol requires that the operation of the terminals is either as a slave station or as a master station;

transmitting a first signal in accordance with the first predetermined signaling protocol;

wherein, in response to the transmission of the first signal, the radio terminal is inhibited as a source of interference; and

wherein if the radio terminal forms part of an existing network, the first signal is such that;

the policing terminal mimics a slave station of the existing network by transmitting a response to inquiry messages from the master station, so as to join the existing network;

the policing terminal transmits a signal to swap the master/slave roles; and

the policing terminal, acting as master station, transmits a disconnect message to each of the slave stations.

2. A method as claimed in claim 1 wherein the policing terminal, when mimicking the slave station, starts its transmissions slightly earlier than the station which it is trying to mimic.

3. A method of protecting an apparatus from radiofrequency interference in a predetermined radio-frequency band, comprising, at a policing terminal:

detecting the presence of a radio terminal operable to generate interference in the predetermined radio-frequency band and in accordance with a first predetermined signaling protocol, wherein the signaling protocol specifies operation of a wireless local area network in which the network comprises a plurality of terminals, and wherein the protocol requires that the operation of the terminals is either as a slave station or as a master station;

transmitting a first signal in accordance with the first predetermined signaling protocol;

wherein, in response to the transmission of the first signal, the radio terminal is inhibited as a source of interference; and

wherein if the radio terminal forms part of an existing network, the first signal is such that;

the policing terminal mimics a slave station of the existing network by transmitting a response to inquiry messages from the master station, so as to join the existing network;

the policing terminal detects the addresses of the other terminals in the network; and

the policing terminal mimics the master station, and then transmits a disconnect message to each of the slave stations.

4. A method as claimed in claim 3 wherein the policing terminal, when mimicking the slave station and when mimicking the master station, starts its transmissions slightly earlier than the station which it is trying to mimic.

5. A method of protecting an apparatus from radiofrequency interference in a predetermined radio-frequency band, comprising, at a policing terminal:

detecting the presence of a radio terminal operable to generate interference in the predetermined radio-frequency band and in accordance with a first predetermined signaling protocol, wherein the signaling protocol specifies operation of a wireless local area network in which the network comprises a plurality of terminals, and wherein the protocol requires that the operation of the terminals is either as a slave station or as a master station;

transmitting a first signal in accordance with the first predetermined signaling protocol;

wherein, in response to the transmission of the first signal, the radio terminal is inhibited as a source of interference; and

wherein if the radio terminal forms part of an existing network, the first signal is such that;

the policing terminal mimics a slave station of the existing network by transmitting a response to inquiry messages from the master station, so as to join the existing network; and

the policing terminal transmits a short burst of noise at the current frequency during preamble or sync word transmission in the network, to effectively destroy each packet on the network.

6. A method as claimed in claim 5 wherein the policing terminal, when mimicking the slave station, starts its transmissions slightly earlier than the station which it is trying to mimic.

7. A method of protecting an apparatus from radiofrequency interference in a predetermined radio-frequency band, comprising, at a policing terminal:

detecting the presence of a radio terminal operable to generate interference in the predetermined radio-frequency band and in accordance with a first predetermined signaling protocol, wherein the signaling protocol specifies operation of a wireless local area network in which the network comprises a plurality of terminals, and wherein the protocol requires that the operation of the terminals is either as a slave station or as a master station;

transmitting a first signal in accordance with the first predetermined signaling protocol;

wherein, in response to the transmission of the first signal, the radio terminal is inhibited as a source of interference; and

wherein if the radio terminal forms part of an existing network;

the policing terminal calculates the slot timing of the network, and detects the addresses of all the stations in the existing network;

and the first signal is such that;

the policing terminal mimics a master station of the existing network by transmitting a disconnect signal to each of the stations on a single frequency, with random clock information in place of network clock information.

8. A method as claimed in claim 7 wherein the policing terminal, when mimicking the slave station, starts its transmissions slightly earlier than the station which it is trying to mimic.

9. A method of protecting an apparatus from radiofrequency interference in a predetermined radio-frequency band, comprising, at a policing terminal:

detecting the presence of a radio terminal operable to generate interference in the predetermined radio-frequency band and in accordance with a first predetermined signaling protocol, wherein the signaling protocol specifies operation of a wireless local area network in which the network comprises a plurality of terminals, and wherein the protocol requires that the operation of the terminals is either as a slave station or as a master station;

transmitting a first signal in accordance with the first predetermined signaling protocol;

wherein, in response to the transmission of the first signal, the radio terminal is inhibited as a source of interference; and

wherein if the radio terminal does not form part of an existing network;

the policing terminal detects signal packets of the types which occur when a new network is being formed; and

the policing terminal mimics a master station of the network that is being formed, by transmitting a disconnect signal to each of the slave stations.

10. A method of protecting an apparatus from radiofrequency interference in a predetermined radio-frequency band, comprising, at a policing terminal:

detecting the presence of a radio terminal operable to generate interference in the predetermined radio-frequency band and in accordance with a first predetermined signaling protocol, wherein the signaling protocol specifies operation of a wireless local area network in which the network comprises a plurality of terminals, and wherein the protocol requires that the operation of the terminals is either as a slave station or as a master station;

transmitting a first signal in accordance with the first predetermined signaling protocol;

wherein, in response to the transmission of the first signal, the radio terminal is inhibited as a source of interference; and

wherein if the radio terminal does not form part of an existing network;

the policing terminal detects inquiry packets indicating that a new network is being formed,;

the policing terminal joins the network as a slave station;

the policing terminal transmits a signal to swap the master/slave roles; and

the policing terminal, acting as master station, transmits a disconnect message to each of the slave stations.

11. A method of protecting an apparatus from radiofrequency interference in a predetermined radio-frequency band, comprising, at a policing terminal:

detecting the presence of a radio terminal operable to generate interference in the predetermined radio-frequency band and in accordance with a first predetermined signaling protocol, wherein the signaling protocol specifies operation of a wireless local area network in which the network comprises a plurality of terminals, and wherein the protocol requires that the operation of the terminals is either as a slave station or as a master station;

transmitting a first signal in accordance with the first predetermined signaling protocol;

wherein, in response to the transmission of the first signal, the radio terminal is inhibited as a source of interference; and

wherein if the radio terminal does not form part of an existing network;

the policing terminal detects paging packets indicating that a new network is being formed;

the policing terminal detects the clock information of the master station; and

the policing terminal mimics the master station, and then transmits a disconnect message to each of the slave stations.

12. A policing terminal for protecting an apparatus from radiofrequency interference in a predetermined radio-frequency band, the policing terminal comprising:

a processor configured to detect the presence of a radio terminal operable to generate interference in the predetermined radio-frequency band and in accordance with a first predetermined signaling protocol, wherein the signaling protocol specifies operation of a wireless local area network in which the network comprises a plurality of terminals, and wherein the protocol requires that the operation of the terminals is either as a slave station or as a master station;

a transmitter configured to transmit a first signal in accordance with the first predetermined signaling protocol;

wherein, in response to the transmission of the first signal, the radio terminal is inhibited as a source of interference; and

wherein the processor is configured to mimic a station of such a network; and

the transmitter is configured to transmit a disconnect message to each of the slave stations.