Method for seamlessly changing the value of an extended unique identifier for a non-AP station associated with an AP station - Patents.com

Abstract

A method for seamlessly changing a value of an extended unique identifier of a non-AP station associated with an AP station. According to some embodiments of the present disclosure, a method for changing a value of an extended unique identifier (EUI) of a non-access point (non-AP) station associated with an access point (AP) station is provided, where both the non-AP station and the AP station use the same mechanism for determining a new value of the EUI. After obtaining an EUI change start time and a duration of a transition period and after determining a new value of the EUI, data is transmitted to or received from the non-AP station or AP station with the changed or new EUI value from the obtained EUI change start time up to the duration of the obtained transition period. An item of information for obtaining an EUI change start time is received from or transmitted from the non-AP station or AP station.

Description

[Technical field]

[0001] The present invention relates to wireless communications, and more particularly to user privacy during wireless communications. [Background technology]

[0002] The approaches described in this section could be pursued, but are not necessarily approaches that have been previously conceived or pursued. Thus, unless otherwise stated herein, the approaches described in this section are not prior art to the claims of this application, and are not admitted to be prior art by inclusion in this section. Moreover, all embodiments are not necessarily intended to solve all or any of the problems raised in this section.

[0003] Wireless communication networks are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcast, etc. These wireless networks may be multiple access networks capable of supporting multiple users by sharing available network resources. Examples of such multiple access networks include Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, and Single Carrier FDMA (SC-FDMA) networks. The 802.11 family of standards adopted by the Institute of Electrical and Electronics Engineers (IEEE) provides many mechanisms for wireless communication between stations.

[0004] Today, the evolution of wireless systems, driven by user demands and the requirements of the General Data Protection Regulation (GDPR), has brought privacy concerns to the forefront. While the global wireless industry continues to improve wireless services and user experiences, it is faced with an increasing need to protect users' personally identifiable information from increasingly sophisticated user tracking and profiling activities.

[0005] In particular, the Medium Access Control (MAC) address of a user device constitutes one of the data that can be used to track this user. Indeed, by means of the MAC address, the Access Points (APs) of a wireless network can monitor the location of a user's mobile device (tablet, laptop, mobile phone, etc.) without the user's consent. This is because the mobile phone is configured to discover surrounding access points to the wireless network. As the user moves, the mobile phone of the user sends requests to determine if there are access points nearby, and these requests identify the mobile phone that sent the request and include, among other things, the MAC address of the mobile phone. Access points that hear these requests can respond. In the context of Wi-Fi networks, defined in the IEEE 802.11 standard, this procedure is called a Probe Request / Response exchange.

[0006] Thus, even if the mobile phone is not connected to a Wi-Fi network, surrounding access points may receive its MAC address. The user can then be tracked by recovering the user's trajectory from the access points to which the mobile phone transmitted its MAC address. Furthermore, if the mobile phone is associated with one of the access points (i.e., the user is connected to the associated Wi-Fi network through that access point) and the user has provided personal identifying information in the past (such as name, place of residence, etc.), the access point may have recorded the mobile phone's MAC address in association with that identifying information in its database. Thus, even if the user is not connected to a Wi-Fi network, this identifying information can be recovered by comparing the MAC address included in the Probe Request with the MAC addresses used for past associations.

[0007] In the context of Wi-Fi networks, a solution has been proposed by the IEEE 802.11 working group to limit the risk of users being tracked, which consists of dynamically changing the MAC address of the user device. This mechanism is called the Randomized and Changing MAC (RCM) procedure. It was originally introduced as a privacy enhancing feature in the 802.11aq Pre-Association Service Discovery Task Group and was eventually included in the standard IEEE Std 802.11-2020. It involves periodically changing the MAC address of non-AP stations (i.e., stations that are not access points) to a random value while the non-AP stations are not associated with a network (or equivalently an access point). Non-AP stations may construct a randomized MAC address from a locally administered address space, as defined in IEEE Std 802®-2014 and IEEE Std 802c™-2017.

[0008] More specifically, a new Management Information Base (MIB) variable that can be controlled by an external management entity is identified. This variable is called "dot11MACPrivacyActivated". When dot11MACPrivacyActivated is set to "true", non-AP stations can apply certain mechanisms for privacy enforcement at the MAC level, including RCM.

[0009] A device's MAC address, or EUI-48 address, is an extended unique identifier (EUI) consisting of 48 bits. This address can be either universally administered or locally administered. Universally administered addresses are assigned to a device uniquely by the manufacturer. Conversely, locally administered addresses are assigned to a device by software or a network administrator, replacing a physical burned-in address. The penultimate bit of the first octet of the MAC address, also called the "U / L bit" (for "universal / local bit"), i.e. the seventh bit of the first octet of the address, indicates whether it is universally administered (when set to 0) or locally administered (when set to 1). The least significant bit of the first octet of the MAC address, also called the "I / G bit" (for "individual / group bit"), i.e. the eighth bit of the first octet of the address, indicates whether the frame is sent to only one receiving device (when set to 0, indicating a unicast transmission) or to multiple devices (when set to 1, indicating a multicast transmission). When the RCM mechanism operates in a non-AP station, the MAC address of the non-AP station is changed randomly (e.g., periodically). More specifically, the U / L bit is set to 1, the I / G bit is set to 0, and the remaining 46 bits are randomly generated using a pseudorandom function (PRF). When the RCM operates, counters in all sequence number spaces used to identify data frames (MAC Service Data Unit (MSDU) packets or Management MAC Protocol Data Unit (MMPDU) frames) must be reset, and the non-AP station also resets the seed used in the PHY DATA scrambler of the next physical layer protocol data unit (PPDU) to be transmitted.

[0010] Recently, solutions have been proposed to solve this problem, but they all suffer from a lack of flexibility regarding the application of new MAC addresses. In particular, a change in the MAC address of a non-AP station that is already registered with an AP station requires that ongoing communication be terminated prior to the change of UID. The same problem occurs, for example, when an AP station decides to change a critical element of the network it manages (such as a frequency band). As a result, such an event must be carefully anticipated by all stations in the network by stopping ongoing communication prior to the change.

[0011] Due to the fact that a user's privacy depends primarily on how frequently their MAC addresses change, existing mechanisms do not accommodate it well, leaving non-AP stations within the Basic Service Set (BSS) of an AP station traceable.

[0012] Therefore, there is a need for a method that allows a non-AP station to seamlessly apply the Randomized and Changing MAC procedure without stopping existing communications established with the access point or with other non-AP stations in the BSS. Hereinafter, such a method may be referred to as "Extended RCM" (ERCM) or "Seamless Extended RCM" (SERCM). Summary of the Invention

[0013] The present invention is devised to address one or more of the above-mentioned concerns.

[0014] In this context, a solution is provided to improve the modification of an extended unique identifier, such as a MAC address, of a non-AP station associated with an AP station or another non-AP station.

[0015] According to a first aspect of the present invention, there is provided a method for changing a value of an Extended Unique Identifier (EUI) of a non-access point (non-AP) station associated with an access point (AP) station, both of the non-AP station and the AP station using the same mechanism for determining a new value of the EUI, the method comprising: Obtaining the EUI change start time and the duration of the transition period; determining a new value for the EUI; using the changed EUI value and the new EUI value to transmit data to or receive data from the other of the non-AP station and the AP station for a duration from the obtained EUI change start time up to the obtained duration of the transition period; A method is provided that includes:

[0016] Thus, the method of the present invention makes it possible to change the value of the extended unique identifier of a non-AP station associated with an AP station without stopping existing communications established with the AP station or with another non-AP station of the BSS.

[0017] As known to those skilled in the art, an EUI is a unique identifier assigned to a device's network interface controller for use as a network address during wireless communication, for example, in accordance with IEEE 802 networking technology. Typically, an EUI may include 48 bits (EUI-48, also known as a MAC address) or 64 bits (EUI-64).

[0018] This EUI may be a locally unique identifier, typically reduced to 12 bits (EUI-12 is also called Station AID, short for Association Identifier), such an identifier being unique in the context of the BSS.

[0019] According to some embodiments, at least an item of information for deriving the EUI change start time is received from or transmitted to the other of the non-AP station and the AP station. According to other embodiments, the EUI change start time is derived based on a common event received or detected by both the non-AP station and the AP station. According to yet other embodiments, the EUI change start time is derived from a predefined time instant known at both the non-AP station and the AP station.

[0020] Furthermore, according to some embodiments, the method further includes shortening the duration of the obtained transition period when it is determined that neither the non-AP station nor the AP station needs to use the changed EUI value before the duration of the obtained transition period has elapsed, thereby enabling a shortening of the duration of the period for changing the value of the EUI.

[0021] Further, according to some embodiments, the method further includes determining whether a transmit buffer of the non-AP station and / or a transmit buffer of the AP station contains data to be transmitted using the changed EUI value.

[0022] Further, according to some embodiments, determining whether a transmit buffer of the other of the non-AP station and the AP station contains data to be transmitted using the changed EUI value includes determining whether an EUI value used in transmitting frames from the other of the non-AP station and the AP station to the one of the non-AP station and the AP station is a new value of the EUI.

[0023] According to further some embodiments, determining whether a transmit buffer of the other of the non-AP station and the AP station contains data to be transmitted using the EUI value to be changed includes (i) transmitting a frame from the one of the non-AP station and the AP station to the other of the non-AP station and the AP station, and (ii) determining whether an EUI value used to receive an acknowledgment of the transmitted frame is the EUI value to be changed.

[0024] Further, according to some embodiments, at least an item of information for obtaining the duration of the transition period is received from or transmitted to the other of the non-AP station and the AP station.

[0025] A duration of the transition period may be determined as a function of an amount of data to be transmitted using the changed EUI value or may be predetermined. The obtained duration of the transition period may be transmitted to the other of the non-AP station and the AP station.

[0026] Moreover, according to some embodiments, the method further includes determining that the value of the EUI should be changed.

[0027] Further, according to some embodiments, the EUI of the non-AP station is the MAC address of the non-AP station, ie, EUI-48.

[0028] Further, according to some embodiments, a request to change the value of the EUI is sent by the AP station and received by the non-AP station. This request may be specific to one non-AP station (in which case only the EUI of the non-AP station is changed) or may be sent to all non-AP stations associated with the AP and supporting the EUI change procedure (in which case all EUIs of the non-AP stations are changed simultaneously). For example, the request to change the value of the EUI may be a beacon frame.

[0029] Further, according to some embodiments, the item of information for obtaining the EUI change start time is a counter included in the beacon frame, the counter indicating the number of Target Beacon Transmission Times (TBTT). For example, after sending a request to change the value of the EUI, multiple subsequent beacon frames may be sent by the AP station and received by the non-AP station, each subsequent beacon frame including a respective value of the counter, the value of the counter being decremented by one unit for each subsequent beacon frame, and the EUI change start time is the time when the beacon frame with the value of the counter equal to zero is sent from the AP station and received by the non-AP station.

[0030] Further, according to some embodiments, a request to change the value of the EUI is sent by the non-AP station and received by the AP station.

[0031] Further according to some embodiments, the item of information for obtaining the EUI change start time is included in the request to change the value of the EUI.

[0032] Further, according to some embodiments, the item of information for obtaining the EUI change start time is a number k of Target Beacon Transmission Times (TBTTs), and the EUI change start time is the time at which the kth beacon frame is transmitted from the AP station or received by the non-AP station since communication of the request.

[0033] Further, according to some embodiments, the item of information for obtaining the EUI change start time is a time value, the EUI change start time is the time when a beacon frame is transmitted from the AP station or received by the non-AP station, and the beacon frame is transmitted or received corresponding to the first beacon frame after the time value is reached.

[0034] According to further some embodiments, the physical layer of the non-AP station is configured to manage at least two different values ​​of the EUI, and the AP station is configured to manage a list of at least two different values ​​of the EUI from the obtained EUI change start time up to the duration of the obtained transition period.

[0035] According to another aspect of the present disclosure, there is provided an apparatus including a processing unit configured to perform each of the steps of the above-mentioned method.

[0036] This aspect of the disclosure has similar advantages to those discussed above.

[0037] According to some embodiments, a station identified by an extended unique identifier (EUI) value, the station having a memory and a processing circuit coupled to the memory, the processing circuit comprising: Get the EUI change start time and the duration of the transition period, determining a new value for the EUI; using the changed EUI value and the new EUI value for transmitting data to or receiving data from another station for a duration of the transition period from the obtained EUI change start time up to the obtained transition period; A station is provided that is configured to:

[0038] At least some of the methods according to the present disclosure may be computer-implemented. Thus, the present disclosure may take the form of an entirely hardware embodiment, an entirely software (including firmware, resident software, microcode, etc.) embodiment, or an embodiment combining software and hardware aspects, all of which may be referred to generally herein as a "circuit," "module," or "system." Furthermore, the present disclosure may take the form of a computer program product embodied in any tangible medium of expression having computer-usable program code embodied in the medium.

[0039] Since the solutions of the present disclosure may be implemented in software, the solutions of the present disclosure may be embodied as computer readable code for provision to a programmable device on any suitable carrier medium. Tangible carrier media may include storage media such as floppy disks, CD-ROMs, hard disk drives, magnetic tape devices, or solid-state memory devices. Transient carrier media may include signals such as electrical, electronic, optical, acoustic, magnetic, or electromagnetic signals, e.g., microwave or RF signals. [Brief description of the drawings]

[0040] Some embodiments of the present invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which like reference numbers refer to similar elements: [Figure 1] FIG. 1 illustrates an example of a network system in which some embodiments of the present invention may be implemented. [Figure 2a]FIG. 2a illustrates an example of steps performed in a non-AP station to change its MAC address according to some embodiments of the present invention. [Figure 2b] FIG. 2b illustrates example steps performed by an AP station to change the MAC address of one of its associated non-AP stations, according to some embodiments of the invention. [Diagram 3] FIG. 3 is a diagram illustrating example steps performed at a non-AP station or an AP station upon receipt of a frame or when a frame is ready to be transmitted, in accordance with some embodiments of the invention. [Figure 4] FIG. 4 is a diagram illustrating example steps performed by a non-AP station or an AP station to request a change in the MAC address of the non-AP station (if these steps are performed by the non-AP station) or the non-AP station (if these steps are performed by the AP station) in accordance with some embodiments of the present invention. [Diagram 5] FIG. 5 illustrates example steps performed by a non-AP station or an AP station to change the MAC address of the non-AP station (if these steps are performed by the non-AP station) or the non-AP station (if these steps are performed by the AP station) upon receipt of a MAC address change request in accordance with some embodiments of the present invention. [Figure 6] FIG. 6 illustrates a first example sequence of steps for operating a procedure for changing the MAC address of a non-AP station associated with an AP station, according to some embodiments of the invention. [Figure 7] FIG. 7 illustrates a second example sequence of steps for operating a procedure for changing the MAC address of a non-AP station associated with an AP station, according to some embodiments of the invention. [Figure 8]FIG. 8 is a diagram showing an example of a frame format for activating and operating the MAC address change procedure. [Figure 9] FIG. 9 is a diagram illustrating an example of a frame format for operating an AP station initiated MAC address change procedure according to some embodiments of the present invention. [Figure 10] FIG. 10 illustrates an example of a communication device of a wireless network configured to implement at least one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] According to some embodiments of the present invention, a method is provided for changing the value of an Extended Unique Identifier (EUI) of a non-access point (non-AP) station associated with an access point (AP) station, e.g., a MAC address of the non-AP station. Both the non-AP station and the AP station start the EUI change process at the same time, and have the same time period for performing the actual EUI change. During the so-called transition period (the period from the start to the end of the EUI change process), both the old and new EUIs are valid and can be used by the AP station and / or the non-AP station. To that end, a new EUI, called a transient EUI, is associated with the non-AP station. When the transition period ends, the current EUI is replaced by the transient EUI, and the old EUI is no longer used.

[0042] During the transition period, AP and non-AP stations monitor the EUI used in frame transmissions to determine whether the EUI change is valid. To shorten the transition period, an EUI different from the emitter EUI may be used to acknowledge frame reception depending on whether there are frames buffered using the old EUI.

[0043] The transition duration can be exchanged during the association procedure, for example in a dedicated information element broadcast in the AP's beacon frame or in a probe request or probe response frame that can be exchanged during the association procedure. Alternatively, the duration can be indicated in the EUI change request frame.

[0044] To ensure the duration of the transition period, both the AP station and the non-AP station may start a timer with the value of the transition period, and when this timer expires, both the AP station and the non-AP station MUST apply the EUI change (if not already applied).

[0045] For convenience of explanation, the following will be an example of changing the value of the MAC address of a non-AP station. The same applies to changing the value of the EUI of a non-AP station, for example, the station AID.

[0046] FIG. 1 illustrates an example of a network system in which some embodiments of the present invention may be implemented.

[0047] For purposes of illustration, FIG. 1 depicts an 802.11 network (i.e., Wi-Fi network) system 100 including four wireless devices: an access point station (AP) 105 and three non-AP stations (non-AP STAs) 110a, 110b, 110c. Of course, the number of non-AP stations 110a, 110b, 110c may be different than three. The AP station 105 provides a wireless connection between the non-AP stations 110a, 110b, 110c and a broader network, such as the Internet (not shown). The connection of one of the non-AP stations 110a, 110b, 110c to the AP 105 may be performed by a standardized process called association. Once the non-AP station is associated with the AP station, the non-AP station can transmit data to and receive data from the network via the AP station.

[0048] The AP station 105 may include, be implemented as, or be known as a Node B, radio network controller (RNC), evolved Node B (eNB), 5G next-generation base station (gNB), base station controller (BSC), base transceiver station (BTS), base station (BS), transceiver function (TF), wireless router, wireless transceiver, basic service set (BSS), enhanced service set (ESS), radio base station (RBS), or other terminology. It may be a standalone product or may be integrated into equipment such as a broadband remote access server (BRAS).

[0049] The non-AP stations 110a, 110b, and / or 110c may include, be implemented as, or be known as a subscriber station, subscriber unit, mobile station (MS), remote station, remote terminal, user terminal (UT), user agent, user device, user equipment (UE), user station (STA), or other terminology. In some implementations, the non-AP station may be or include a mobile phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless connectivity capabilities, or other suitable processing device connected to a wireless modem. Thus, one or more aspects taught herein may be incorporated into a telephone (e.g., a mobile phone or smartphone), a computer (e.g., a laptop), a tablet, a portable communication device, a portable computing device (e.g., a personal data assistant), an entertainment device (e.g., a music or video device, or a satellite radio), a global positioning system (GPS) device, or any other suitable device configured to communicate via a wireless or wired medium. In some aspects, some of the non-AP stations 110a, 110b, and 110c may be wireless nodes. Such wireless nodes may provide, for example, connectivity for or to a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link.

[0050] The AP station 105 manages a set of stations that organize access to the wireless medium for communication purposes. All stations (AP station 105 and non-AP stations 110a, 110b, 110c) form a service set called a Basic Service Set (BSS) (although other terminology may be used). Note that the AP station 105 may manage more than one BSS, each BSS being uniquely identified by a unique Basic Service Set Identifier (BSSID) and managed by a separate virtual AP station implemented in the physical AP station 105.

[0051] FIG. 2a illustrates an example of steps performed in a non-AP station to change its MAC address according to some embodiments of the present invention.

[0052] The algorithm shown in FIG. 2a is executed by a non-AP station at a SERCM change start time, for example the start time referenced 610 in FIG. 6 or 710 in FIG.

[0053] As shown, the first step is directed to determining the maximum SERCM transition period duration (step 200), hereafter referred to as SERCM transition period duration, transition period duration, or transition duration. This duration may be defined as a time value expressed in milliseconds, TU (Time Unit), as a number of TBTT (Target Beacon Transmission Time), or by any other indication of duration. According to some embodiments, the determination of the SERCM transition period duration is based on the utilization level of the transmission buffer and / or by retrieving a value stored upon receipt of an information element, such as information element 900 of FIG. 9. According to other embodiments, the transition duration is a predefined value, such as a value defined by the 802.11 standard. According to yet other embodiments, the transition duration is a combination of the received value and a value set by the administrator, such as the maximum of the received value and the value set by the administrator.

[0054] Then, a change of the local MAC address is initiated (step 205) from the current MAC address (also called old MAC address), denoted @MAC(n), to a new MAC address, denoted @MAC(n+1), by starting a transition duration. Starting the transition duration involves indicating to the physical (PHY) layer that the new MAC address @MAC(n+1) should be added as a temporary MAC address to the list of MAC addresses that the AP station handles. From the perspective of the PHY layer, all packets addressed with one of the MAC addresses included in this list should be decoded and forwarded to the MAC layer for further operation. Currently, the MAC layer already handles different MAC addresses (usually the PHY handles a single unicast MAC address of the station and possibly a group address of the group to which the station belongs).

[0055] In some embodiments of the invention, the PHY layer of the considered non-AP station handles two unicast MAC addresses, the first one being the classical unicast MAC address of the station seen as a unique identifier of the station, and the second one being a temporary unicast MAC address. The presence of the two unicast MAC addresses is only valid during a transition period. The configuration of the unicast MAC address by the MAC layer can be performed, for example, by a request known as a PHY-CONFIG request, which is part of the PHY SAP (Service Access Point) interface defined in the 802.11 standard. In some embodiments of the invention, a function for defining a temporary MAC address is added to the PHY SAP. In other embodiments, the temporary MAC address is added as a new parameter to the PHY CONFIG function used to configure different parameters of the PHY layer.

[0056] After setting the transient MAC address with the new MAC address, the PHY layer can decode frames addressed to non-AP stations (value of the RA field) either by its own unique MAC address or by the transient MAC address.

[0057] Furthermore, during the step of initiating the transition period (step 205), the non-AP station sets the values ​​of two bits that can be used to determine the status of its own local transmission buffer, hereinafter denoted as Local transmission Buffer Status (or LocalBS), and the status of the transmission buffer of the AP station with which the non-AP station is associated, hereinafter denoted as RemoteBS. These two bits indicate, respectively, whether the local transmission buffer and the transmission buffer of the AP station are ready for transmission and contain some packets addressed according to the old MAC address (i.e., @MAC(n)), or are ready for transmission or retransmission and contain some frames addressed with the old MAC address. According to some embodiments, the RemoteBS bit is set to false during the step of initiating the transition period to indicate that the non-AP station considers that the transmission buffer of the AP station contains data to be transmitted using the old MAC address. Also, the RemoteBS bit is set to true during the transition period to indicate that the non-AP station considers that the transmission buffer of the AP station does not contain data to transmit using the old MAC address. Also, during the step of initiating the transition period, LocalBS is set to false if the local transmit buffer is not empty (meaning the local buffer contains data to be transmitted using the old MAC address), and is set to true otherwise.

[0058] As described above, the transition period ends after or before the duration of the transition period, depending on the state of the local buffer and the state of the AP station's transmit buffer. Thus, in some embodiments, the non-AP station starts a timer with the duration value determined in step 200. When this timer expires, the transition period ends. In this case, both the LocalBS bit and the RemoteBS bit are forced true, and the MAC address change period ends.

[0059] The use of a timer to limit the maximum duration of a transition period may be relevant in certain conditions, such as when an AP station or a non-AP station sets the receive address of an acknowledgment frame with the value of the transmit address of the frame it is acknowledging (the management of the acknowledgment address is described in more detail with reference to step 310 of FIG. 3). In such a case, if the AP station (respectively the non-AP station) has no frames to send to the non-AP station (respectively the AP station), there is no way for the non-AP station (respectively the AP station) to determine the state of the AP station's transmit buffer (respectively the non-AP station's transmit buffer).

[0060] According to some embodiments, all new packets prepared for transmission and stored in the local transmit buffer are addressed using the transient MAC address value (new MAC address @MAC(n+1)) during the transition period, which ensures that no new packets addressed with the old MAC address (@MAC(n)) are added to the local transmit buffer.

[0061] As shown in Fig. 2a, the non-AP station transmits and receives packets during step 210 and clears the contents of its transmit buffer, which may contain some packets with the old prepared MAC address (@MAC(n)). The transmission of these packets follows the normal medium access rules defined in the standard.

[0062] An example of a mechanism for transmitting and receiving packets (step 210) will now be described in detail with reference to FIG.

[0063] After receiving or transmitting the packet (or in parallel), the non-AP station determines whether the transition period should be stopped (step 215). The transition period should be stopped either because it has determined that the old MAC address is no longer needed or because the maximum transition period duration has elapsed.

[0064] According to some embodiments, if both the LocalBF and RemoteBF bits are set to true, the non-AP station determines that it no longer needs the old MAC address and the transition period ends, otherwise the algorithm loops at step 210 as shown.

[0065] If both the LocalBF and RemoteBF bits are set to true, the non-AP station sets its "normal" unique MAC identifier with the value of the temporary MAC address. In this case, the two MAC addresses (i.e., the MAC address and the transient MAC address) have the same value and the transition period is considered to be over. In some embodiments, if a timer was set during the MAC address initialization process (step 205), the timer is cleared.

[0066] If the duration of the maximum transition period has elapsed while the old MAC address is still in use, packets or frames stored in the transmit buffer of the non-AP station that should use the old MAC address to be transmitted may be discarded, in some embodiments, these packets may be modified to be transmitted using the new MAC address.

[0067] FIG. 2b illustrates example steps performed by an AP station to change the MAC address of one of its associated non-AP stations according to some embodiments of the invention.

[0068] Similar to the algorithm described with reference to FIG. 2a, the algorithm shown in FIG. 2b is executed by an AP station at a SERCM change start time, for example the start time with reference to 610 in FIG. 6 or 710 in FIG.

[0069] Similarly, a first step is directed to determining the maximum SERCM transition period duration (step 250), also referred to as SERCM transition period duration, transition period duration, or transition duration. Step 250 is similar to step 200 of FIG. 2a. The SERCM transition period duration may be based on the utilization level of the transmit buffer and / or may be obtained from a value stored upon reception of an information element such as information element 900 of FIG. 9, may be a predefined value, e.g. a value defined by the 802.11 standard, or may correspond to a combination of a received value and a value set by an administrator, e.g. the maximum of the received value and a value set by an administrator.

[0070] Next, a change of the MAC address of the considered non-AP station from its current MAC address @MAC(n) (also called the old MAC address) to a new MAC address @MAC(n+1) is initiated by indicating in association with the non-AP station the transient MAC address (@MAC(n+1)) in addition to its unique MAC address (@MAC(n)) (step 255). It is recalled here that the AP station maintains some internal table to store a set of parameters for each station associated with it. In some embodiments, the transient MAC address is a new entry in this table and is set with the value of the new MAC address for the considered non-AP station.

[0071] Furthermore, during the step of initiating the duration of the transition period (step 255), the AP station sets the values ​​of two bits that can be used to determine the state of its local transmission buffer, hereinafter denoted as Local Transmit Buffer Status (or LocalBS), associated with the considered non-AP station (i.e., the non-AP station whose MAC address has changed), and the state of the transmission buffer of the considered non-AP station, hereinafter denoted as RemoteBS. These two bits indicate, respectively, whether the transmission buffer of the AP station and the transmission buffer of the considered non-AP station are ready for transmission and contain some frames to be addressed according to the old MAC address (i.e., @MAC(n)). According to some embodiments, the RemoteBS bit is set to false during the step of initiating the transition period to indicate that the AP station considers that the transmission buffer of the considered non-AP station contains data to be transmitted with the old MAC address. Also, the RemoteBS bit is set to true to indicate that during the transition period, the AP station considers that the transmission buffer of the considered non-AP station does not contain data to transmit with the old MAC address. Also, in the step of initiating the transition period, if the AP station's transmit buffer contains data to be transmitted (using the old MAC address) to the considered non-AP station, LocalBS is set to false, otherwise it is set to true.

[0072] As mentioned above, the transition period ends after the duration of the transition period or sooner, depending on the state of the local buffer and the state of the transmit buffers of the non-AP stations considered. Thus, in some embodiments, the AP station starts a timer with the duration value determined in step 250. When this timer expires, the transition period ends. In this case, both the LocalBS bit and the RemoteBS bit are forced true, and the MAC address change period ends.

[0073] According to some embodiments, all new packets prepared for transmission to the considered non-AP station and stored in the local transmit buffer are addressed using the value of the considered non-AP station's transient MAC address (new MAC address @MAC(n+1)) during the transition period, which ensures that no new packets addressed with the old MAC address (@MAC(n)) are added to the transmit buffer.

[0074] Steps 260 and 265 of FIG. 2b are similar to steps 210 and 215 described with reference to FIG. 2a.

[0075] If the duration of the maximum transition period has elapsed while the old MAC address is still in use, packets or frames stored in the AP station's transmit buffer using the old MAC address for transmission may be discarded, in some embodiments, these packets may be modified to be transmitted using the new MAC address.

[0076] An example of a mechanism for transmitting and receiving packets (step 260) will now be described in detail with reference to FIG.

[0077] FIG. 3 is a diagram showing example steps (e.g., steps 210 or 260 of FIG. 2a or FIG. 2b, respectively) performed at a non-AP station or an AP station upon receiving a frame or when a frame is ready to be transmitted, in accordance with some embodiments of the present invention.

[0078] As shown, when a frame event is detected (step 300), if the frame event is directed to the reception of a frame, the frame is received by the station for which it is addressed (the non-AP station under consideration, or the AP station with which the non-AP station under consideration is associated) (step 305). A test is performed to determine if the received frame was sent using a new MAC address. If a new MAC address is used, the RemoteBS bit is set to true. Furthermore, if the received frame requires an acknowledgement, an acknowledgement is sent to the station that sent the frame (step 310), otherwise step 315 is executed directly (step 310 is optional).

[0079] Upon acknowledging a received frame, the station receiving the frame prepares an acknowledgment to send to the sender of the frame and identifies the MAC address of the station sending the acknowledgment.

[0080] According to some embodiments, the receiving MAC address (RA) of the acknowledgement frame (i.e., the MAC address of the acknowledgement receiver to use) is the same as the one indicated as the sending address of the received frame (i.e., the MAC address of the sender of the frame being acknowledged indicated in this frame). This embodiment follows the standard acknowledgement mechanism.

[0081] According to other embodiments, the receiving MAC address (RA) of the acknowledgement frame is set as a function of the value of the LocalBF bit. For example, if the local transmit buffer does not contain packets addressed with the old MAC address, the acknowledgement frame is addressed using the new MAC address (i.e., the temporary MAC address), regardless of the address indicated as the transmit address of the received frame. Conversely, if the local transmit buffer contains one or more packets addressed with the old MAC address, the acknowledgement frame is addressed using the old MAC address, regardless of the address indicated as the transmit address of the received frame. Thus, according to these embodiments, the acknowledgement can be addressed using a receiving address (RA address) that is different from the transmit address (TA address) of the received packet. This mechanism, unlike current implementations, allows the receiving station to indicate to the transmitting station that it is ready to change its MAC address since its buffer no longer contains packets addressed with the old MAC address. Thus, these embodiments allow the change of MAC address to be performed faster, i.e., shortening the transition period.

[0082] Then, after sending an acknowledgment, or if no acknowledgment is sent, the station receiving the frame determines whether the old MAC address of the considered non-AP station is still in use and therefore whether a change of MAC address has been made: If both the LocalBF and RemoteBF bits are set to true, the station determines that the old MAC address no longer needs to be maintained and therefore the transition period may be terminated (as described with reference to steps 215 and 265 of Figures 2a and 2b, respectively).

[0083] As shown, upon detecting a frame event (step 300), if the frame event is directed to the transmission of a frame (e.g., by determining that the local transmit buffer of the station performing the steps illustrated in FIG. 3 is not empty), the station attempts to access the medium for data transmission and transmits at least a portion of the buffered data (step 320). The data is transmitted to the considered non-AP station or to the AP station with which the considered non-AP station is associated (depending on whether the steps illustrated in FIG. 3 are performed at the considered non-AP station or at the AP station with which the considered non-AP station is associated).

[0084] According to some embodiments, data stored in the local transmit buffer that is ready to be transmitted and is to be transmitted using the old MAC address should be transmitted before data stored in the local transmit buffer that is ready to be transmitted and is to be transmitted using the new MAC address. Thus, when a station transmits data, the station checks whether the data is to be transmitted using the old MAC address or the new MAC address, and when the data is to be transmitted using the new MAC address, the station sets the LocalBF bit to true to indicate that there is no data stored in the local transmit buffer that is to be transmitted using the old MAC address.

[0085] If the transmitted frame requires an acknowledgement, the station waits for an acknowledgement (step 325), otherwise step 315 is executed directly (step 325 is optional).

[0086] When an acknowledgment corresponding to a transmitted frame is received (step 325), if this frame was transmitted using the old MAC address, the station compares the receiving MAC address (RA) of the acknowledgment frame with the transmitting address of the corresponding transmitted frame.

[0087] In some embodiments, a received acknowledgment always has the same receiving address as the sending address of the corresponding frame sent by the station, in accordance with a standard implementation of the acknowledgment mechanism (step 320). In these embodiments, the station cannot determine the state of the remote transmit buffer (i.e., does it contain data to be sent using the old MAC address) and relies on receiving a frame to determine the state of the remote transmit buffer, as described with reference to step 305.

[0088] In other embodiments, the receive address of the received acknowledgment may be different from the transmit address of the corresponding transmit frame, as described with reference to step 310. According to these embodiments, if the receive MAC address of the acknowledgment frame is set to a new MAC address, the RemoteBF bit is set to true to indicate that the transmit buffer of the station that sent the acknowledgment does not contain data to be transmitted using the old MAC address.

[0089] Then, after receiving an acknowledgment, or if no acknowledgment is received, the station that sent the frame determines whether the old MAC address of the considered non-AP station is still in use, and therefore whether a change of MAC address has occurred: If both the LocalBF and RemoteBF bits are set to true, the station determines that the old MAC address no longer needs to be maintained, and therefore the transition period may end (as described with reference to steps 215 and 265 of Figures 2a and 2b, respectively).

[0090] FIG. 4 shows example steps performed by a non-AP station or by an AP station to request a change in the MAC address of a non-AP station (if these steps are performed by the non-AP station) or to request a change in the MAC address of a non-AP station (if these steps are performed by an AP station) in accordance with some embodiments of the present invention.

[0091] As shown, the first step is directed to determining the duration of the maximum transition period, which corresponds to step 200 of Fig. 2a (if the station performing the steps of Fig. 4 is a non-AP station) or step 250 of Fig. 2b (if the station performing the steps of Fig. 4 is an AP station).

[0092] According to some embodiments, this step can be performed with a predefined duration dictated by a system administrator. According to other embodiments, the duration can be determined as a function of the amount of data stored in a local transmission buffer, for example the amount of data transmitted using the old MAC address of the non-AP station considered. According to yet other embodiments, the duration can be determined as a function of the amount of data stored in the transmission buffer of a remote station (for example the non-AP station considered if the steps of FIG. 4 are performed by an AP station, or the AP station if the steps of FIG. 4 are performed in the non-AP station considered), which amount of data is used to increase or decrease the duration of the transition period to better match the estimated time required to clear the transmission buffer from data addressed with the old MAC address. These embodiments may be combined to determine the maximum transition period duration.

[0093] Next, a MAC Address Change Request frame (or a SERCM MAC Address Change Request frame) is transmitted (step 400). This frame may include the duration of the maximum transition period previously determined. Such a frame may follow the format shown in FIG.

[0094] If a response to the MAC address change request is received (step 405), it is determined that the MAC address change has been accepted, and therefore the MAC address change may be initiated (steps 205 and after in FIG. 2a if the station performing the steps in FIG. 4 is a non-AP station, or steps 255 and after in FIG. 2b if the station performing the steps in FIG. 4 is an AP station).

[0095] FIG. 5 illustrates example steps performed by a non-AP station or an AP station to change the MAC address of a non-AP station (if these steps are performed by a non-AP station) or a non-AP station (if these steps are performed by an AP station) upon receipt of a MAC address change request in accordance with some embodiments of the present invention.

[0096] As shown, the first step is directed to receiving a MAC address change request frame (step 500), or a SERCM MAC address change request frame, e.g., a frame conforming to the format illustrated in Figure 8. Upon receipt of the MAC address change request frame, it is determined whether the latter includes a maximum transition period duration (e.g., the value of SERCM.max transition period field 820 of Figure 8). If so, it is stored.

[0097] Next, it is determined whether a MAC address change may occur. If a MAC address change may occur, the station performing the steps shown in Figure 5 sends back a change response (or SERCM change response) indicating that it has accepted the MAC address change (step 505).

[0098] Next, the duration of the maximum transition period is determined, which corresponds to step 200 of Fig. 2a (if the station performing the steps of Fig. 5 is a non-AP station) or step 250 of Fig. 2b (if the station performing the steps of Fig. 5 is an AP station).

[0099] According to some embodiments, this step may be performed using a previously received maximum transition period duration, for example the maximum transition period duration received in step 500 .

[0100] After determining the duration of the maximum transition period, the MAC address change may be initiated (from step 205 in FIG. 2a if the station performing the steps of FIG. 5 is a non-AP station, or from step 255 in FIG. 2b if the station performing the steps of FIG. 5 is an AP station).

[0101] FIG. 6 illustrates a first example sequence of steps for operating a procedure for changing the MAC address of a non-AP station associated with an AP station according to some embodiments of the invention.

[0102] The MAC address change procedure basically includes two phases: a first phase in which new MAC addresses of one or more non-AP stations are calculated and the AP station and the one or more non-AP stations identify an effective change start time, and a second phase corresponding to the effective change of the MAC addresses of these non-AP stations. The effective change of the MAC address starts at a time called the SERCM change start time and ends at the latest at a time called the maximum SERCM change end time, from which the newly calculated MAC addresses are used for data exchange between the considered non-AP stations and the AP station with which they are associated. Thus, during the change procedure, each of the considered non-AP stations changes its MAC address from the current value @MAC(n) to the new value @MAC(n+1). During the transition period, both the current and the new values ​​of the MAC address are valid.

[0103] New MAC addresses must be calculated by considering non-AP stations and AP stations.

[0104] At the SERCM change start time, the non-AP and AP stations initiate an effective address change procedure and at (or before) the maximum SERCM change end time, modify their respective registries by updating the MAC address of each of the considered non-AP stations from @MAC(n) to @MAC(n+1).

[0105] In other words, at the beginning of the transition period, both the AP and the non-AP STAs start changing the MAC addresses of the changing non-AP STAs.

[0106] The manner in which the AP station and the non-AP station determine the new MAC address to use is outside the scope of this disclosure. The AP station and the non-AP station may, for example, store a list of MAC addresses, and each time a change of the MAC address has to be performed, the next value in the list is selected as the new MAC address. However, in such an embodiment, security problems may arise if a third party has access to the list. Alternatively, the same functionality may be used by the non-AP station and the AP station with which it is associated to determine, for example, the index of the next MAC address to use in a given list of MAC addresses. This index may advantageously be determined randomly.

[0107] Other MAC address selection methods may also be used, for example based on the use of a pseudorandom function (PRF) with the same input parameters, such that both the non-AP station and the AP station with which it is associated obtain the same address value @MAC(n+1).

[0108] Returning to Fig. 6 and referring to Fig. 1, there is illustrated a change procedure initiated by the AP station 105 and directed to the non-AP stations 110a and 110b of the BSS for which the initiation procedure was performed. In other words, according to these embodiments, the AP station 105 indicates to the non-AP stations 110a and 110b for which the initiation procedure was performed that they need to change their MAC addresses, and the non-AP stations 110a and 110b start changing their MAC addresses at the same time (the SERCM change start time).

[0109] For ease of explanation, the SERCM change start time may be expressed in units of a number of Target Beacon Transmission Times (TBTTs). Of course, the SERCM change start time may be expressed in other ways, such as a real time (which may be rounded to avoid problems due to imperfect synchronization of the non-AP and AP station clocks).

[0110] According to the IEEE 802.11 standard, an AP station periodically (every TBTT) transmits a beacon frame, which is a management frame that contains information related to the network, to non-AP stations of the BSS. The beacon frame may therefore contain a field that stores an item of information indicating the date of change of the SERCM. For example, such an item of information may represent the value of a counter that is decremented in each successive beacon frame transmitted by the AP station to indicate that a change of the MAC address is in progress and to indicate the date of the SERCM change. For example, each beacon frame that the AP station 105 transmits to the non-AP stations 110a and 110b of the BSS may contain an information element as described below with reference to FIG. 9. The counter is initially set to a value corresponding to the time at which the change must be activated (for example, an initial value k indicates that the change must be activated at (k+1) TBTT, where k is an integer), and is decremented by one unit with each subsequent transmission of a beacon frame. When the counter reaches the value 0, the change must be activated. Thus, all transmissions of frames following a beacon frame with the counter equal to 0 must be performed with the new MAC address.

[0111] Referring to FIG. 6, the non-AP stations 110a and 110b first receive a beacon frame containing a counter, denoted as SERCM Change counter, set to a value k (step 600). This indicates that the non-AP stations 110a and 110b (at which the initiation procedure has been performed) must change their respective MAC addresses at a time corresponding to (k+1) TBTT. The next beacon frame is then transmitted from the AP station 105 to the non-AP stations 110a and 110b containing a SERCM Change counter with a value of (k-1) (step 605). After transmitting the (k+1) beacon frames, the AP station 105 transmits a beacon frame to the non-AP stations 110a and 110b indicating that the SERCM Change counter is equal to 0 and that the non-AP stations 110a and 110b must start changing their respective MAC addresses (step 610). The new addresses of non-AP stations 110a and 110b should be determined any time between steps 600 and 610, ie, after requesting a MAC address change and before initiating the effective MAC address change.

[0112] All transmissions between the AP station 105 and the non-AP stations 110a and 110b that occur after the maximum SERCM change end time 615 should be performed using the new MAC addresses of the non-AP stations 110a and 110b.

[0113] The transition time (referenced at 620) between the SERCM change start time 610 and the maximum SERCM change end time 615 is advantageous in that it allows AP and non-AP stations to transmit frames addressed to the old MAC address @MAC(n) that were buffered in the transmit buffer, thereby allowing the MAC address to be changed without interrupting ongoing transmissions, eliminating the negative performance impact of frequent MAC address changes.

[0114] It should be understood that although the embodiment described with reference to FIG. 6 uses beacon frames, other types of frames may be used as well.

[0115] FIG. 7 illustrates a second example sequence of steps for operating a procedure for changing the MAC address of a non-AP station associated with an AP station, according to some embodiments of the invention.

[0116] According to an alternative embodiment shown in FIG. 7, the MAC address change procedure may be initiated by the non-AP station 110a.

[0117] As shown, a request to change the MAC address of the non-AP station under consideration (i.e., non-AP station 110a in this example) is sent from non-AP station 110a to AP station 105 (step 700). The request may be a "SERCM change request," such as "SERCM change Request" 800, described below with reference to FIG. 8. The request may include an indication regarding the SERCM change date and the SERCM maximum transition period duration.

[0118] For ease of explanation, it may include a field (e.g., SERCM Change Date field 815 as shown in FIG. 8) indicating the date of the next MAC address change, e.g., in units of TBTTs. For example, a value set to k may indicate that the change should be initiated at (k+1) TBTT, while a value set to 0 may indicate that the next MAC address should be applied immediately. Thus, all message transmissions following the transmission of a beacon frame associated with a counter equal to 0 should be performed using the new MAC address.

[0119] The SERCM change request frame may also include a field indicating the maximum duration of the transition period (e.g., SERCM maximum transition period field 820 as shown in FIG. 8). Upon expiration of the transition period, both AP and non-AP stations should use the new MAC address.

[0120] As shown, in response to the MAC address change request, the AP station 105 may acknowledge receipt of the request and agree to change the MAC address of the non-AP station 110a by sending a “SERCM change response,” such as “SERCM change response” 850, described with reference to FIG. 8, to the non-AP station 110a (step 705).

[0121] According to some embodiments, the non-AP station 110a may implement a counter (e.g., a counter equal to k or (k-1)) reflecting the SERCM change date when sending a MAC address change request, the SERCM change date being expressed here as a number of TBTTs. Each time a new beacon frame is received from the AP station 105, the counter is decremented by one unit. When the non-AP station 110a receives a beacon frame corresponding to the SERCM change date from the AP station 105, i.e. when the counter reaches the value 0 (step 710), the change of the MAC address is initiated. When the transition period ends (reference 720), the new MAC address of the non-AP station 110a becomes valid (at the beginning of the next TBTT). This means that all transmissions from the transmission of the beacon frame corresponding to the maximum SERCM change end time (step 715) onwards will be made with the new MAC address.

[0122] Note that the new address of non-AP station 110a should be determined any time between steps 700 and 710, i.e., from requesting the MAC address change to initiating the effective MAC address change.

[0123] Although the examples described with reference to Figures 6 and 7 are based on the use of beacon frames and TBTT, other embodiments exist. Indeed, according to some embodiments, it may be necessary to share an indication related to the time when the change should be made between the considered non-AP stations and the AP stations with which they are associated, and to provide the non-AP stations and the AP stations with a means to count that time. For example, it is possible to transmit the actual date, as long as the non-AP stations and the AP stations have access to the same clock or can synchronize their clocks. The change of MAC address may be performed periodically, at a predetermined time, or on demand.

[0124] Also, based on the example shown in Fig. 6, it should be noted that an AP station may request that only one non-AP station change its MAC address. For that purpose, a SERCM change request similar to the one described with reference to Fig. 7 may be sent from the AP station to the considered non-AP station.

[0125] Figure 8 shows example frame formats for enabling and operating the MAC address change procedure. All frame formats represented in Figure 8 are identified by a "Category" field that is assigned a specific value k in the so far reserved range [31,125] as specified in Table 9-51 of IEEE Std 802.11-2020. For illustrative purposes, the category value assigned to the SERCM action frame may be set to 31. Other values ​​may be used.

[0126] For example, to Table 9-51-Category Values, the following could be added: TIFF2025504623000002.tif31161

[0127] Furthermore, the frame format represented in Figure 8 is further identified by a one-octet "SERCM Action" field immediately following the Category field. The values ​​of the SERCM Action field may be defined in the following table and may be inserted at the end of 9.6 Action frame format detail of the standard IEEE Std 802.11-2020: TIFF2025504623000003.tif42161

[0128] Still for ease of explanation, a SERCM Action field value set to 4 may correspond to a SERCM change request, and a SERCM Action field value set to 5 may correspond to an ERCM change response.

[0129] 8, frame format 800 corresponds to a frame for requesting a MAC address change, and frame format 850 corresponds to a frame for responding to a request for a MAC address change. As shown, frame formats 800 and 850 include category fields referenced at 805 and 855, respectively, and SERCM action fields referenced at 810 and 860, respectively.

[0130] Thus, the SERCM change request 800 may include a Category field 805 set to a value of 31 and a SERCM Action field 810 set to a value of 4.

[0131] Additionally, the SERCM change request 800 may include a SERCM Change Date field 815 referenced at 815 and a SERCM max. transition period field 820 referenced at 815 .

[0132] The SERCM Change Date field 815 may indicate the date on which the MAC address change should be applied. According to some embodiments, this date may be expressed as a number of target beacon transmit times (TBTT). Other embodiments are possible. For example, the date on which the MAC address change should be applied may be an actual date. In such an embodiment, non-AP stations and AP stations should use (or have access to) synchronized clocks to prevent a change being made in one device and not the other.

[0133] The SERCM max. transition period field 820 may indicate the maximum duration of a MAC address change transition period, again expressed as a number of Target Beacon Transmission Times (TBTTs) corresponding to the number of TBTTs between the start of the transition period and its end. This value may also be expressed in milliseconds or TUs (time units). Other implementations are possible.

[0134] The SERCM change Response 850 may include a Category field 855 set to a value of 31 and a SERCM Action field 860 set to a value of 5.

[0135] FIG. 9 is a diagram illustrating an example of a frame format for operating an AP station initiated MAC address change procedure according to some embodiments of the present invention.

[0136] This may correspond to an information element (IE) defined in clause 9.4.2 of the standard IEEE Std 802.11-2020.

[0137] An IE dedicated to the SERCM procedure, called a SERCM IE, may be specified, such as SERCM IE 900. As shown, the IE is identified by an Element ID (e.g., Element ID 905) and an Element ID Extension (e.g., Element ID Extension 915, which is assigned to a specific value in the so far reserved range [99,255] as specified in Table 9-92 of IEEE Std 802.11-2020). For illustrative purposes, the Element ID Extension to identify the SERCM IE may be set to 99.

[0138] Thus, the Element ID field 905 of the SERCM IE 900 may be set to 255 and the Element ID Extension field 915 of the SERCM IE 900 may be set to 99.

[0139] Additionally, the SERCM IE 900 includes a Length field referenced at 910, which indicates the number of octets in the IE 900 excluding the Element ID field 905 and the Length field 910. According to the illustrated example, the value is 2.

[0140] The SERCM IE 900 further includes a SERCM Change counter field (or SERCM max. transition period) referenced at 920.

[0141] The SERCM max. transition period field 920 indicates the maximum duration of the transition period, which may again be expressed as a number of Target Beacon Transmission Times (TBTTs) corresponding to the number of TBTTs from the start of the transition period to its end. This value may be expressed in milliseconds or TUs (time units). Other embodiments are possible.

[0142] Figure 10 shows a schematic example of a communication device, which may correspond to any of the stations described with reference to Figure 1, of a wireless network configured to implement at least some embodiments of the present invention. The communication device referred to as 1000 may preferably be a device such as a microcomputer, a workstation or a lightweight portable device. The communication device 1000 may include a communication bus 1013 to which the following may be connected: - a central processing unit 1001, such as a processor, denoted as CPU; a memory 1003, denoted MEM, for storing the executable code of a method or a method step according to an embodiment of the invention, and registers adapted to record variables and parameters necessary for the execution of the method; and at least two communication interfaces 1002 and 1002' connected via respective transmit and receive antennas 1004 and 1004' to a wireless communication network, for example a communication network according to one of the standards of the IEEE 802.11 family.

[0143] Preferably, the communications bus 1013 may provide communication and interoperability between various elements included in or connected to the communications device 1000. The representation of a bus is not limiting, and in particular a central processing unit is operable to communicate instructions to any element of the communications device 1000 directly or by way of another element of the communications device 1000.

[0144] The executable code may be stored in a memory, either read-only, hard disk or removable digital medium, such as a disk. According to an optional variant, the executable code of the program may be received by the communication network, via the interface 1002 or 1002', to be stored in the memory 1003 of the communication device 1000 before being executed.

[0145] In some embodiments, communications device 1000 may be a programmable device that uses software to implement embodiments of the present invention, while alternatively, some embodiments of the present invention may be implemented in whole or in part in hardware (e.g., in the form of an application specific integrated circuit (ASIC)).

[0146] The embodiments of the present invention may be realized by a computer of a system or device that includes one or more circuits (e.g., application specific integrated circuits (ASICs)) for reading and executing computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to as a "non-transitory computer-readable storage medium") to perform one or more functions of the above-mentioned embodiments, for example, by a method performed by reading and executing computer executable instructions from a storage medium to perform one or more functions of the above-mentioned embodiments and / or controlling one or more circuits to perform one or more functions of the above-mentioned embodiments. The computer may have one or more processors (e.g., central processing unit (CPU), microprocessor unit (MPU)) and may include a separate computer or a network of separate processors for reading and executing the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or a storage medium. The storage medium may include, for example, one or more of a hard disk, a random access memory (RAM), a read-only memory (ROM), storage of a distributed computing system, an optical disk (such as a compact disk (CD), a digital versatile disk (DVD)), a flash memory device, a memory card, and the like.

[0147] The words "comprise," "include," "incorporate," "contain," "is," "have," and the like, when interpreting this specification and the related claims, are to be interpreted in a non-exclusive manner, i.e., to allow for the presence of other items or components not expressly defined. Reference to the singular shall be construed as a reference to the plural and vice versa.

[0148] Those skilled in the art will readily appreciate that the various parameters disclosed herein can be changed and the various disclosed embodiments can be combined without departing from the scope of the present invention.

Claims

1. 1. A method for changing a value of an extended unique identifier (EUI) of a non-access point (non-AP) station associated with an access point (AP) station, both of the non-AP station and the AP station using the same mechanism for determining a new value of the EUI, the method comprising: Obtaining an EUI change start time and a duration of a transition period; determining a new value for the EUI; and using the changed EUI value and the new EUI value to transmit data to or receive data from the other of the non-AP station and the AP station for a duration of the transition period up to the obtained from the obtained EUI change start time; The method includes:

2. 2. The method of claim 1, wherein at least an item of information for deriving the EUI change start time is received from or transmitted to the other of the non-AP station and the AP station.

3. 2. The method of claim 1, further comprising: shortening a duration of the acquired transition period if it is determined that neither the non-AP station nor the AP station needs to use the EUI value that is changed before the acquired duration of the transition period has elapsed.

4. The method of claim 3 , further comprising: determining whether a transmit buffer of the non-AP station and / or a transmit buffer of the AP station contains data to be transmitted with the EUI value being changed.

5. 5. The method of claim 4, wherein determining whether a transmit buffer of the other of the non-AP station and the AP station contains data to be transmitted using the changed EUI value comprises determining whether an EUI value used in transmitting frames from the other of the non-AP station and the AP station to the one of the non-AP station and the AP station is a new value of the EUI.

6. 5. The method of claim 4, wherein determining whether a transmit buffer of the other of the non-AP station and the AP station contains data to be transmitted using the EUI value to be changed comprises: (i) transmitting a frame from the one of the non-AP station and the AP station to the other of the non-AP station and the AP station; and (ii) determining whether an EUI value used to receive an acknowledgment of the transmitted frame is the EUI value to be changed.

7. 7. A method according to claim 1, wherein at least an item of information for obtaining the duration of the transition period is received from or transmitted to the other of the non-AP station and the AP station.

8. The method according to claim 1 , wherein the duration of the transition period is determined as a function of the amount of data to be transmitted using the changed EUI value.

9. The method of claim 1 , wherein the duration of the transition period is preset.

10. The method of claim 1 , wherein the obtained duration of the transition period is transmitted to the other of the non-AP station and the AP station.

11. The method of claim 1 , further comprising determining that a value of the EUI should be changed.

12. The method of claim 1 , wherein the EUI of the non-AP station is a MAC address of the non-AP station.

13. The method according to claim 2 , wherein a request to change the value of the EUI is sent by the AP station and received by the non-AP station.

14. The method of claim 13 , wherein the request to change the value of the EUI is a beacon frame.

15. 15. The method of claim 14, wherein the item of information for obtaining the EUI change start time is a counter included in the beacon frame, the counter indicating a number of Target Beacon Transmission Times (TBTTs).

16. after the request to change the value of the EUI is transmitted, a plurality of subsequent beacon frames are transmitted by the AP station and received by the non-AP station, each subsequent beacon frame including a respective value of the counter, and the value of the counter is decremented by one unit for each subsequent beacon frame; The method of claim 15 , wherein the EUI change start time is a time when a beacon frame with a value of the counter equal to zero is transmitted from the AP station and received by the non-AP station.

17. The method according to claim 2 , wherein a request to change the value of the EUI is sent by the non-AP station and received by the AP station.

18. The method of claim 17 , wherein the item of information for obtaining the EUI change start time is included in the request to change a value of the EUI.

19. 20. The method of claim 18, wherein the item of information for obtaining the EUI change start time is a number k of Target Beacon Transmission Times (TBTTs), the EUI change start time being the time at which the kth beacon frame is transmitted from the AP station or received by the non-AP station since communication of the request.

20. 20. The method of claim 18, wherein the item of information for obtaining the EUI change start time is a time value, the EUI change start time is the time when a beacon frame is transmitted from the AP station or received by the non-AP station, and the beacon frame is transmitted or received corresponding to the first beacon frame after the time value is reached.

21. 21. The method of claim 1, wherein the physical layer of the non-AP station is configured to manage at least two different values ​​of the EUI, and the AP station is configured to manage a list of at least two different values ​​of the EUI from the acquired EUI change start time up to the acquired duration of the transition period.

22. A computer program product for a programmable device, the computer program product comprising sequences of instructions for performing each of the steps of the method according to any one of claims 1 to 21, when the computer program product is loaded into and executed by the programmable device.

23. A non-transitory computer readable storage medium having stored thereon computer program instructions for carrying out the steps of the method according to any one of claims 1 to 21.

24. A station identified by an Extended Unique Identifier (EUI) value, the station having a memory and a processing circuit coupled to the memory; The processing circuitry includes: Obtain the EUI change start time and the duration of the transition period; determining a new value for the EUI; using the changed EUI value and the new EUI value for transmitting data to or receiving data from another station for a duration of the transition period up to the obtained from the obtained EUI change start time; A station configured as follows.

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