Search

EP-4740523-A1 - METHOD FOR CHANGING A VALUE OF AN EXTENDED UNIQUE IDENTIFIER OF A NON-AP STATION ASSOCIATED WITH AN AP STATION

EP4740523A1EP 4740523 A1EP4740523 A1EP 4740523A1EP-4740523-A1

Abstract

The present invention concerns a method of communication between a first station and a second station, the first station being capable of changing an identifier from a current identifier to a new identifier, the method comprising at the first station, during a margin period setting a set of identifiers, including the current and the new identifiers, as valid identifiers of the first station for received frames, and setting one of the current or the new identifier as valid identifier of the first station for emitted frames.

Inventors

  • Baron, Stéphane
  • NEZOU, PATRICE
  • SEVIN, JULIEN

Assignees

  • Canon Kabushiki Kaisha

Dates

Publication Date
20260513
Application Date
20240703

Claims (15)

  1. 1 . A method of communication between a first station and a second station, the first station being capable of changing an identifier from a current identifier to a new identifier, the method comprising at the first station, during a margin period: - setting a set of identifiers, including the current and the new identifiers, as valid identifiers of the first station for receiving frames, and - setting one of the current or the new identifier as valid identifier of the first station for emitting frames.
  2. 2. The method of claim 1 , wherein the set of valid identifiers apply to the receiver address (RA) field in received frames.
  3. 3. The method of claim 1 , wherein the one identifier applies to the transmitter address (TA) field in emitted frames.
  4. 4. A method of communication between a first station and a second station, the first station being capable of changing an identifier from a current identifier to a new identifier, the method comprising at the second station, during a margin period: - setting a set of identifiers, including the current and the new identifiers, as valid identifiers of the first station for receiving frames, and - setting one of the current or the new identifier as valid identifier of the first station for emitting frames.
  5. 5. The method of claim 1 , wherein the set of valid identifiers apply to the transmitter address (TA) field in received frames.
  6. 6. The method of claim 1 , wherein the one identifier applies to the receiver address (RA) field in emitted frames.
  7. 7. The method of any preceding claims, further comprising determining a usage period start time at which the identifier of the first station is changed from the current identifier to the new identifier.
  8. 8. The method of claim 7, wherein the margin period is a forward margin period starting prior the start of the usage period.
  9. 9. The method of claim 8, further comprising, upon reception of a frame addressed to the first station with the new identifier during the forward margin period, shifting forward the start time of the usage period, or a following usage period, based on the time difference between the reception of the frame and the determined usage period start time.
  10. 10. The method of claim 7, wherein the margin period is a backward margin period ending after the start of the usage period.
  11. 11. The method of claim 10, further comprising, upon reception of a frame addressed to the first station with the current identifier during the backward margin period, shifting backward the start time of a following usage period based on the time of reception of the frame.
  12. 12. The method of any preceding claims wherein the first station is a non-access point (AP) station and the second station is an AP station.
  13. 13. The method of any preceding claims wherein station identifiers are MAC addresses.
  14. 14. A station comprising: means for changing an identifier of the first station from a current identifier to a new identifier; means for setting a set of identifiers, including the current and the new identifiers, as valid identifiers of the first station, during a margin period, for receiving frames, and means for setting one of the current or the new identifier as valid identifier of the first station, during the margin period, for emitting frames.
  15. 15. A non-transitory computer-readable medium storing a program which, when executed by a microprocessor or computer system in a wireless device, causes the wireless device to perform the method of Claim 1 or 4.

Description

METHOD FOR CHANGING A VALUE OF AN EXTENDED UNIQUE IDENTIFIER OF A NON-AP STATION ASSOCIATED WITH AN AP STATION FIELD OF THE INVENTION The present invention relates to wireless communications and more specifically to user privacy during wireless communications. BACKGROUND OF INVENTION The approaches described in this section could be pursued, but are not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section. Furthermore, all embodiments are not necessarily intended to solve all or even any of the problems brought forward in this section. Today, the evolution of wireless systems has brought privacy concerns at the forefront, driven by user demand and requirements of the General Data Protection Regulation (GDPR). The global wireless industry is faced with the growing need to protect users’ personally identifiable information from increasingly sophisticated user tracking and user profiling activities, while continuing to improve wireless services and the user experience. In particular, the Media Access Control (MAC) address of a user device constitutes a piece of data that can be used to track this user. Indeed, the access points (APs) of wireless networks can monitor the locations of mobile devices (tablets, laptops, mobile phones, etc.) of a user without his/her consent, by means of their MAC addresses. This is because mobile phones are configured to discover surrounding access points to wireless networks. As a user moves, his/her mobile phone sends requests to determine if there are any access points nearby, these requests identifying the mobile phone which sends these requests and including in particular the MAC address of the mobile phone. Access points that hear these requests can respond. In the context of Wi-Fi networks as defined by IEEE 802.11 standards (Wi-Fi is a trademark), this procedure is called Probe Request/Response exchange. So even when a mobile phone is not connected to a Wi-Fi network, surrounding access points may receive its MAC address. It is then possible to track a user by reconstructing his/her trajectory from access points to which his/her mobile phone has sent its MAC address. In addition, if the mobile phone has been associated with one of the access points (i.e., the user has connected to an associated Wi-Fi network through that access point) and the user has provided personal identification information (name, place of residence, etc.) in the past, the access point may have recorded in a database the MAC address of the phone in association with the identification information. Therefore, even if the user is not connected to the Wi-Fi network, this identity information could be recovered by comparing the MAC address contained in a Probe Request to the MAC address used for the past association. In the context of Wi-Fi networks, a solution has been proposed by the IEEE 802.11 working group to limit the risk of a user being tracked, and consists in dynamically modifying the MAC address of the user device. This mechanism is called Randomized and Changing MAC (RCM) procedure. It has been originally introduced as a privacy enhancing feature in the 802.11aq Pre-Association Service Discovery Task Group and finally included in the standard IEEE Std 802.11-2020. It comprises periodical change of the MAC address of a non-AP station or STA (i.e., a station which is not an access point) to a random value, while the non-AP station is not associated with a network (or, equivalently, with an access point). The non-AP station may construct the randomized MAC address from the locally administered address space as defined in IEEE Std 802®- 2014 and IEEE Std 802c™-2017. More specifically, a new Management Information Base (MIB) variable controllable by an external management entity has been specified. This variable is called ‘dotH MACPrivacyActivated’. When dotH MACPrivacyActivated is set to “true”, the non- AP station can apply specific mechanisms for enhancing the privacy at MAC level, including RCM. The MAC address, or Elll-48 address, of a device is an Extended Unique Identifier (EUI) composed of 48 bits. It can be administered universally or locally. A universally administered address is uniquely assigned to the device by the manufacturer. On the contrary, a locally administered address is assigned to the device by a software or a network administrator, and replaces the physical burned-in address. The second- least-significant bit of the first octet of the MAC address, i.e., the seventh bit of the first octet of the address, also referred to as “U/L bit” (for “Universal/Local bit”), indicates whether it is universally (when set to 0) or locally (when set to 1) administered. The leastsignificant bit of the first octet of the MAC address, i.e., the eighth bit of the first octet