Backoff Timer for Network Reattachment

Abstract

Various communication systems can benefit from improved network signaling or attachment. In some embodiments, a method can include receiving, at a network node, an initial attachment request message from a user equipment. The method can further include issuing a backoff timer when the initial attachment request from the user equipment is accepted. The backoff timer can include a duration during which the user equipment is not permitted to re-attach to the network. Additionally, the method can include receiving, at the network node, another attachment request message from the user equipment. Additionally, the method can include determining whether the duration of the backoff timer has elapsed and rejecting the another attachment request from the user equipment when the duration of the backoff timer has not elapsed.

Description

[0001] Division Explanation

[0002] This application is a divisional application of the Chinese patent application with the application number 201780090564.0 and the title "Backoff Timer for Network Reattachment", which was filed on November 08, 2019. Technical Field

[0003] Various communication systems can benefit from improved network signaling and attachment. For example, some communication systems can benefit from a backoff timer that prevents a user equipment from reattaching to the network during the duration of the timer. Background Art

[0004] Given the current growth rate of cellular technology, it is expected that there will be more than 20 billion Internet of Things (IoT) devices with wireless connections by 2020. A significant number of these devices can be cellular IoT devices connected via a cellular network. Cellular IoT devices (also known as cellular IoT user equipment (UE)) generate bursty but infrequent traffic and have been optimized for infrequent small data transmissions. However, transmitting small data frequently consumes more network resources than sending large amounts of data at a low frequency.

[0005] Mobile service providers typically design their fee models for charging users based on the total data usage within a predefined time period. For example, a mobile service provider charges a user for the number of messages sent within a given month. The provider typically also utilizes rate control methods that can limit or restrict the total number of messages that a UE can transmit within a given time unit. Rate control methods that restrict the number of transmitted messages can include a rate control quota, where the quota defines the number of messages that a UE can send within a given time unit. Such a limit or restriction on the total number of messages is imposed on the UE when the UE attaches to the network.

[0006] Data limitations or constraints such as rate control quotas work under the assumption that the UE remains attached to the network. Thus, rate control methods are applied to the UE starting from when the UE attaches to the network until the UE detaches from the network. However, a UE that detaches and then reattaches to the same network receives a new data limit quota. Thus, in order to bypass or avoid the imposed data limitations or constraints, the UE only needs to reattach to the network. Summary of the Invention

[0007] According to some embodiments, an apparatus may include at least one memory and at least one processor, the at least one memory including computer program code. The at least one memory and the computer program code may be configured to use the at least one processor to cause the apparatus to receive, at least at a network node, an initial attachment request message from a user equipment. The at least one memory and the computer program code may also be configured to use the at least one processor to cause the apparatus to start a backoff timer at least when accepting the initial attachment request from the user equipment. The backoff timer may include a duration during which the user equipment is not allowed to re-attach to the network. Additionally, the at least one memory and the computer program code may be configured to use the at least one processor to cause the apparatus to receive, at least at the network node, another attachment request message from the user equipment. Additionally, the at least one memory and the computer program code may be configured to use the at least one processor to cause the apparatus to at least determine whether the duration of the backoff timer has elapsed, and to reject another attachment request from the user equipment when the duration of the backoff timer has not elapsed.

[0008] In some embodiments, a method may include: receiving, at a network node, an initial attachment request message from a user equipment. The method may also include: starting a backoff timer when accepting the initial attachment request from the user equipment. The backoff timer may include a duration during which the user equipment is not allowed to re-attach to the network. Additionally, the method may include receiving, at the network node, another attachment request message from the user equipment. Additionally, the method may include determining whether the duration of the backoff timer has elapsed, and rejecting another attachment request from the user equipment when the duration of the backoff timer has not elapsed.

[0009] In some embodiments, an apparatus may include means for receiving, at a network node, an initial attachment request message from a user equipment. The apparatus may also include means for starting a backoff timer when accepting the initial attachment request from the user equipment. The backoff timer may include a duration during which the user equipment is not allowed to re-attach to the network. Additionally, the method may include means for receiving, at the network node, another attachment request message from the user equipment. Additionally, the method may include means for determining whether the duration of the backoff timer has elapsed, and means for rejecting another attachment request from the user equipment when the duration of the backoff timer has not elapsed.

[0010] According to certain embodiments, a non-transitory computer-readable medium encoded with instructions that, when executed in hardware, perform a process. The process may include receiving, at a network node, an initial attachment request message from a user equipment. The process may further include, when the initial attachment request from the user equipment is accepted, issuing a backoff timer. The backoff timer may include a duration during which the user equipment is not permitted to attach to the network. Additionally, the process may include receiving, at the network node, a reattachment request message from the user equipment. Additionally, the process may include determining whether the duration of the backoff timer has elapsed and rejecting another attachment request from the user equipment when the duration of the backoff timer has not elapsed.

[0011] According to certain other embodiments, a computer program product may be encoded with instructions for performing a process. The process may include receiving, at a network node, an initial attachment request message from a user equipment. The process may further include, when the initial attachment request from the user equipment is accepted, issuing a backoff timer. The backoff timer may include a duration during which the user equipment is not permitted to reattach to the network. Additionally, the process may include receiving, at the network node, a reattachment request message from the user equipment. Additionally, the process may include determining whether the duration of the backoff timer has elapsed and rejecting another attachment request from the user equipment when the duration of the backoff timer has not elapsed.

[0012] According to certain embodiments, a device may include at least one memory and at least one processor, the at least one memory including computer program code. The at least one memory and the computer program code may be configured to, using the at least one processor, cause the device to send, at least from the user equipment to the network node, an initial attachment request message. The at least one memory and the computer program code may further be configured to, using the at least one processor, cause the device to receive, at least from the network node, a response indicating that the initial attachment request message has been accepted. The response may include a backoff timer or an indication of the backoff timer, and the backoff timer may include a duration during which the user equipment is not permitted to reattach to the network. Additionally, the at least one memory and the computer program code may be configured to, using the at least one processor, cause the device to start, at least, a backoff timer associated with the user equipment. Additionally, the at least one memory and the computer program code may be configured to, using the at least one processor, cause the device to avoid reattaching to the network until after the duration of the backoff timer has elapsed.

[0013] In some embodiments, a method may include sending an initial attachment request message from a user equipment to a network node. The method may further include receiving, from the network node, a response indicating that the initial attachment request message is accepted. The response may include a backoff timer, and the backoff timer may include a duration during which the user equipment is not allowed to re-attach to the network. Additionally, the method may include starting a backoff timer associated with the user equipment. Additionally, the method may further include avoiding re-attaching to the network until after the duration of the backoff timer has elapsed.

[0014] In some embodiments, an apparatus may include means for sending an initial attachment request message from a user equipment to a network node. The apparatus may further include means for receiving, from the network node, a response indicating that the initial attachment request message is accepted. The response may include a backoff timer or an indication of a backoff timer, and the backoff timer may include a duration during which the user equipment is not allowed to re-attach to the network. Additionally, the apparatus may include means for starting a backoff timer associated with the user equipment. Additionally, the apparatus may include means for avoiding re-attaching to the network until after the duration of the backoff timer has elapsed.

[0015] According to some embodiments, a non-transitory computer-readable medium encoded with instructions that, when executed in hardware, perform a process. The process may include sending an initial attachment request message from a user equipment to a network node. The process may further include receiving, from the network node, a response indicating that the initial attachment request message is accepted. The response may include a backoff timer or an indication of a backoff timer, and the backoff timer may include a duration during which the user equipment is not allowed to re-attach to the network. Additionally, the process may include starting a backoff timer associated with the user equipment. Additionally, the process may include avoiding re-attaching to the network until after the duration of the backoff timer has elapsed.

[0016] According to some other embodiments, a computer program product may be encoded with instructions for performing a process. The process may include sending an initial attachment request message from a user equipment to a network node. The process may further include receiving, from the network node, a response indicating that the initial attachment request message is accepted. The response may include a backoff timer or an indication of a backoff timer, and the backoff timer may include a duration during which the user equipment is not allowed to re-attach to the network. Additionally, the process may include starting a backoff timer associated with the user equipment. Additionally, the process may include avoiding re-attaching to the network until after the duration of the backoff timer has elapsed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] To correctly understand the present invention, reference should be made to the accompanying drawings, in which:

[0018] Figure 1 An example of an attachment cycle according to certain embodiments is shown.

[0019] Figure 2 An example of an attachment cycle according to certain embodiments is shown.

[0020] Figure 3 An example of a method according to certain embodiments is shown.

[0021] Figure 4 An example of a method according to certain embodiments is shown.

[0022] Figure 5 An example of a system according to certain embodiments is shown. DETAILED DESCRIPTION

[0023] Certain embodiments allow real-time tracking of how frequently a UE, such as a cellular IoT device, attempts to attach to a network within a given time period. Based on the real-time tracking, a network node can control the network access frequency of the UE by imposing a timer (e.g., an attachment backoff timer). The attachment backoff timer may also be simply referred to as a backoff timer. In other embodiments, the attachment backoff timer may be referred to as an attachment timer, a reattachment timer, or a re-registration timer. The backoff timer may include the duration during which the UE is not allowed to reattach to the network. The network may be any type of communication network, such as a Public Land Mobile Network (PLMN). The use of the backoff timer can help prevent users from bypassing data limit quotas by detaching and then quickly reattaching to the network. Additionally, the UE may detach or deregister from the network when no data is being transmitted. This UE power saving can trigger overly frequent registration or attachment to the network. By prohibiting such behavior, the network operator can reduce the signaling burden on the network and prevent unfair network usage by certain UEs.

[0024] A network node may be able to control the network access frequency of the UE. The network node may be a network entity located in the core network of the 3rd Generation Partnership Project (3GPP), such as an Evolved Packet System (EPS) Mobility Management Entity (MME) or a 5th Generation (5G) Access and Mobility Management Function (AMF), as described in 3GPP TS 23.501 and 3GPP TS 32.501, which are hereby incorporated by reference in their entirety. The UE may detach from the network and then attempt to quickly reattach within a time unit associated with a control rate quota.

[0025] In other embodiments, the UE may remain attached to the network and send another attachment request to the network while still remaining attached to the network, which is also referred to as a reattachment request message in some embodiments. In some embodiments related to 3GPP fourth-generation (4G) technology, a backoff timer may block reattachment requests received after the UE has detached, but allows other types of requests such as tracking area update (TAU) requests as long as the UE remains attached to the network. In 5G technology, which includes a registration request process, in some embodiments, the initial registration request may be blocked by a backoff timer while the UE remains attached to the network, while registration updates may be allowed.

[0026] Certain embodiments can be used to limit or restrict excessive reattachments of the UE to the network. In other words, the network node can prevent UEs that attempt to reattach to the same network one or more times within a given time period from misusing network resources. These limitations or restrictions help reduce the signaling burden on the core network and help prevent deceptive attempts by users to bypass the imposed network rate control by reattaching.

[0027] Figure 1 An example of an attachment cycle according to certain embodiments is shown. Specifically, Figure 1 An attachment cycle 110 is shown, in which the UE remains attached to the network throughout the cycle without attempting to detach or reattach. In attachment cycle 110, a rate control (RC) limit or RC quota can be five messages per hour. Figure 1 The T in represents an uplink message transmitted from the user equipment to the network node. The RC quota of five messages is a per-hour quota, which means that the RC quota restarts after each hour. For example, the RC can be access point name (APN) rate control and / or serving public land mobile network (SPLMN) rate control.

[0028] At time 0 of attachment cycle 110, the UE transmits five uplink messages to the network node. After sending five messages, the UE can be blocked from sending any additional messages during the remaining time of the RC quota hour. For example, if the UE sends five messages within the first 10 minutes, the UE can be blocked from sending any additional messages to the network during the remaining 50 minutes. The RC quota can be imposed on the UE by the network node or can be imposed by the UE itself. In some embodiments, the UE can receive a rate control quota when attached to the network. After the remaining duration of 1 hour has elapsed, the UE can send five additional uplink messages to the network node during the next hour. However, once five messages have been transmitted, the UE is again prevented from sending additional messages during the remaining time of that hour.

[0029] In Figure 1In the second period 120 shown, after the UE sends five messages, rather than waiting for the remaining hours to send additional messages, the UE detaches and then reattaches to the same network, as shown at time 121. By detaching and reattaching to the same network, the UE can receive a new rate control quota that can allow it to transmit additional messages before the remaining period of the hour elapses. From Figure 1 As can be seen, at time 121, the UE detaches and reattaches to the network. Then, the UE sends another five messages to the network node and then detaches and reattaches again at time 122 to receive a new radio control quota. By simply detaching and reattaching to the network, the UE can be able to bypass the RC quota of five messages per hour. In Figure 1 the example shown, the UE manages to send 15 messages during a one-hour period, which exceeds the allotted limit of 10 messages.

[0030] Some embodiments can help prevent the UE from detaching and reattaching to the same network in order to circumvent the imposed rate control quota. Figure 2 An example of an attachment period according to some embodiments is shown. Specifically, Figure 2 a period 210 utilizing a backoff timer is shown, which is configured to prevent the UE from reattaching to the network during a given duration. In some embodiments, the duration of the backoff timer can be based on the duration of the rate control quota. For example, when the RC quota is five messages per hour, the duration of the backoff timer can be one hour or one hour minus the time at which the last of the five messages was sent.

[0031] From Figure 2 As can be seen, once the UE attaches to the network, it can transmit five messages per hour, for example. In some embodiments, once the UE has transmitted the allotted five messages, the backoff timer can be started or triggered. If the UE attempts to reattach to the network during the duration of the backoff timer, the network can prevent the reattachment until after the backoff timer has elapsed. For example, if the rate control quota limits the UE to five messages per hour and the UE transmits all five messages within 15 minutes, the backoff timer can last for 45 minutes. Once the backoff timer expires, the UE can be permitted to reattach to the network, at which point the rate control quota can be restarted for the UE.

[0032] In other embodiments, the backoff timer may be equal to the duration of the applied rate control quota. For example, if a user equipment is constrained to send 5 messages per hour, the backoff timer may start when the UE attaches to the network. The backoff timer may then have a duration of one hour, during which the UE may not be allowed to reattach to the same network. The backoff timer may be restarted every hour. The restart of the backoff timer may be aligned with the restart of the duration of the RC quota.

[0033] In some embodiments, the backoff timer and / or the duration of the backoff timer may be determined and signaled by a network node. The network node may signal the backoff timer when accepting an initial attachment request from the user equipment. Signaling the backoff timer may include determining and sending to the user equipment the backoff timer that has been determined by the network node and / or sending to the user equipment an indication to use a preconfigured timer. The network node may then store or remember the backoff timer duration and signal and / or indicate the backoff timer or the duration of the backoff timer to the UE. In some embodiments, an access network signaling procedure and / or a non-access stratum (NAS) signaling procedure may be used to transmit the backoff timer. For example, the backoff timer may be indicated to the UE as part of a radio resource control (RRC) connection release, TAU, service request message, and / or a control plane service request or detach message. Although the network node transmits the backoff timer to the UE, the network node still continues to track the duration of the backoff timer.

[0034] In some embodiments, the backoff timer may be signaled and / or indicated from the network node to the UE via a message that acknowledges that a reattachment request has been received. In such embodiments, the network node may not reject the UE's reattachment request. Instead, the network may notify the UE that the network node plans to process the request when or after the duration of the backoff timer has elapsed, but instruct the UE to avoid reattaching during the duration of the backoff timer.

[0035] In other embodiments, the backoff timer may be preconfigured in the UE. The preconfiguration may be performed by the network node, for example, when the UE initially attaches to the network. In another example, the backoff timer may be preconfigured in the UE when the UE registers with a mobile service operator. The backoff timer preconfigured in the UE may constrain the UE's ability to reattach to the same network during the duration of the backoff timer. In other words, during the duration of the backoff timer, the UE may even be constrained from sending a reattachment request to the network. The UE may be aware of the start of the duration of the backoff timer upon receiving an indication from the network.

[0036] However, in another embodiment, a pre-configured backoff timer may be included in the reattachment request sent from the UE to the network. The network node may detect the backoff timer associated with the UE and postpone the reattachment of the UE until after the duration of the backoff timer has elapsed. Thus, the implementation of the backoff timer may be performed by the UE itself or by the network node.

[0037] A UE that has received a backoff timer or may have been pre-configured with a backoff timer may start the duration of the backoff timer when detaching from the network. The UE may then not be able to reattach to the same network until after the duration of the backoff timer has elapsed. In some other embodiments, the duration of the backoff timer may be started upon receipt of an indication from the network. The indication from the network may serve as a start command for the backoff timer, regardless of whether the backoff timer was pre-configured at the UE or received at the UE from a network node. In yet another embodiment, the start of the duration of the backoff timer may be implicit. The implicit start may be caused by any action of the network that may cause the UE to detach. Since the start of the timer duration is caused by an action other than detachment, the start may be considered implicit. For example, receiving an RRC connection release may cause the detachment or deregistration of the UE, which may be an implicit trigger for starting the backoff timer.

[0038] In certain embodiments, during the duration of the backoff timer, the UE may be constrained not only from reattaching to the same network but also from requesting attachment to a different network. In some embodiments, the UE may be constrained only from attaching to a different network to avoid the impact of the backoff timer. However, the UE may be allowed to select a different network for any other reason other than to avoid the backoff timer. For example, if the UE loses coverage of the serving network, the backoff timer may not prevent the selection of a different network to regain coverage. Thus, when the UE loses coverage, the backoff timer does not affect certain network selection rules, such as PLMN selection rules.

[0039] In certain embodiments, the UE may be allowed to remain attached after receiving the backoff timer. In other words, the UE may transmit a reregistration request to the network node without detaching or deregistering from the network. During the duration of the backoff timer, the UE may transmit other messages to the network including a registration update request. However, if the UE deregisters or detaches from the network, it may not be allowed to perform a new initial registration process before the backoff timer expires. The transmission of other messages may still be limited or constrained by a control rate quota or any other applicable constraints, and the attachment backoff timer does not affect such other messages.

[0040] As discussed above, in some embodiments, a backoff timer can be operated at both the network node and the UE. The UE can attempt to violate the backoff timer and send a reattachment request to the network before the duration of the backoff timer has elapsed. When receiving such a request, the network can check the backoff timer operated at the network node. If the duration of the backoff timer has not elapsed, the network node can reject the reattachment request. When rejecting the reattachment request, the network can inform the UE of the reason for the rejection. For example, the reason can be that the duration of the backoff timer has not elapsed. In other embodiments, the network node can include the attachment backoff timer in the rejection message sent to the UE. In certain embodiments, in the case where the network node does not reject the request, the backoff timer can be received in an affirmative acknowledgment. As long as the UE has not detached from or deregistered with the network, the backoff timer can allow other traffic including user data and / or signaling.

[0041] Even when the UE is no longer registered, the backoff timer can continue to operate at the network node. Just as the UE can detach and attempt to reattach to the same network to obtain a new rate control quota, in some embodiments, the UE can attempt to deregister and then re-register with the same network. In such embodiments, the network node can continue to operate the backoff timer so as to prevent the re-registered UE from being able to circumvent the imposed rate control quota.

[0042] In certain embodiments, the network can allow some prioritized UEs (such as UEs with high-priority signaling) to reattach to the network during the duration of the backoff timer. The priority of the UE can be indicated to the network in the reattachment request message sent to the network. UEs with high-priority signaling (such as exception reports or emergency signaling) can be allowed to reattach to the network and receive a new radio controller quota. For example, when the UE is running a critical application that requires connectivity during the duration of the backoff timer, the backoff timer, which can be received as a response to the reattachment request, may not prevent the UE from attaching to the network. In some embodiments, the backoff timer can allow or not prevent the attachment or emergency attachment of UEs running critical applications.

[0043] In certain embodiments, the backoff timer can prevent the reattachment of UEs having the same priority level as the priority level of the backoff timer. In other words, the backoff timer can include a priority level associated with the timer. For example, the backoff timer can be associated with a low or normal priority, which does not prevent UEs with a high level of priority from reattaching to the network.

[0044] In some embodiments, a UE with low or normal priority signaling may not be guaranteed reattachment, and the UE may not initiate a reattachment request for low or normal priority signaling. In some embodiments, an indication may be included as part of a backoff timer as to whether the timer is applicable to all signaling or only to non-priority signaling (such as normal or low priority signaling). In some embodiments, a given UE may be network-authorized as a priority UE so as to be considered a priority UE that may reattach during the duration of the backoff timer.

[0045] In some embodiments, a network node may selectively apply a backoff timer to different UEs, or may selectively apply different backoff timers to different UEs. UEs with different subscriptions may have backoff timers selectively applied by the network node. For example, a UE with a higher data limit subscription may also have a shorter backoff timer duration than a UE with a lower data limit subscription. Different subscription levels are mentioned below as different authorization levels. In other embodiments, the network node may selectively apply a backoff timer based on the UE's observed uplink access behavior.

[0046] As discussed above, the triggering or starting of the duration of the backoff timer may occur when the UE receives the backoff timer from the network node. In embodiments where the UE is pre-configured with a backoff timer, the triggering or starting of the duration of the backoff timer may occur upon receipt of an indication from the network. In other embodiments, the triggering or starting of the duration of the backoff timer may occur when the UE detaches from the network. In some embodiments, the UE may detach from the network after receiving the backoff timer from the network node or upon receipt of an indication to activate a pre-configured backoff timer from the network.

[0047] Figure 3 A method according to certain embodiments is shown. Specifically, Figure 3 A method performed by a network node is shown. For example, the network node may be a core network node such as an EPS MME or a 5G MMF. In step 310, the network node may receive an initial attachment request message from the UE. In step 320, the network node may accept the initial attachment request and issue a backoff timer associated with the UE. Issuing the backoff timer may include determining and transmitting the backoff timer to the user equipment. The backoff timer may include a duration during which the user equipment may not be permitted to attach or reattach to the network. In some other embodiments, when the UE has been pre-configured with a backoff timer, the network node may detect the backoff timer.

[0048] In some other embodiments, the network node issues a backoff timer when accepting an initial attachment request. At step 330, when the UE may not be preconfigured with a backoff timer, the network node may send a backoff timer to the UE. In other embodiments, the network node may send an indication of the duration for starting the backoff timer to the UE. At step 340, the network node may determine whether the duration of the backoff timer has elapsed. At step 350, the network node may reject another attachment request from the UE when the duration of the backoff timer has not elapsed. When the duration of the backoff timer has elapsed, the network node may allow the user equipment to reattach to the network. Once the UE is allowed to reattach to the network, the UE may attach to the network, and the network node may reset the rate control quota of the user equipment. The rate control quota may allow the UE to transmit a limited number of messages to the network during a given time period. For example, in Figure 1 and Figure 2 the rate control quota is 5 messages per hour. The duration of the backoff timer may be based on the time associated with the rate control quota.

[0049] Figure 4 shows a method according to certain embodiments. Specifically, Figure 4 shows a method performed by the UE. At step 410, the UE may send an initial attachment request message to the network node. At step 420, the UE may receive a response indicating that the initial attachment request message has been accepted from the network node. In some embodiments, the response may include a backoff timer when the backoff timer may have been determined by the network node. In other embodiments, the response may include an indication of the backoff timer from the network node when the UE is preconfigured with a backoff timer. Receiving the indication or the backoff timer may trigger the start of the backoff timer associated with the UE, as shown in step 430. The UE may then receive a response that may include the backoff timer, which may start the backoff timer.

[0050] At step 440, the UE may transmit other messages to the network during at least a portion of the duration of the backoff timer. The message may be any message other than another attachment request message. Such transmission may be restricted by the rate controller quota. At step 450, the UE may avoid attaching or reattaching to the network until after the duration of the backoff timer has elapsed. After the duration of the backoff timer has elapsed, the UE may send another request message to the network node.

[0051] Figure 5 shows a system according to certain embodiments. It should be understood that Figures 1 to 4Each signal or block in can be implemented by various components such as, for example, hardware, software, firmware, one or more processors, and / or circuits, or a combination thereof. In one embodiment, a system may include a number of devices such as, for example, network node 520 or user equipment (UE) 510. The system may include more than one UE 510 and more than one network node 520. Network node 520 may be an access point, access node, 5G MME and EPS MME, server, host, or any other network core entity that can communicate with the UE.

[0052] Each of these devices may include at least one processor or control unit or module, respectively indicated as 511 and 521. At least one memory may be provided in each device and is respectively indicated as 512 and 522. The memory may include computer program instructions or computer code contained therein. One or more transceivers 513 and 523 may be provided, and each device may also include antennas respectively shown as 514 and 524. Although only one antenna is shown respectively, many antennas and multiple antenna elements may be provided for each device. For example, other configurations of these devices may be provided. For example, in addition to wireless communication, network entity 520 and UE 510 may also be additionally configured for wired communication, and in this case, antennas 514 and 524 may represent any form of communication hardware, not limited to antennas only.

[0053] Transceivers 513 and 523 may be separate transmitters and receivers respectively, or may be both a transmitter and a receiver, or may be a unit or device that can be configured for both transmitting and receiving. The transmitter and / or receiver (as long as it includes the radio part) may also be implemented as, for example, a remote radio head that is not located in the device itself but in the mast. These operations and functions may be performed in a flexible manner in different entities such as nodes, hosts, or servers. In other words, the division of labor may change according to the situation. One possible use is for the network node to deliver local content. One or more functions may also be implemented as (multiple) virtual applications in software that can run on a server.

[0054] User equipment or UE 510 may be a mobile station (MS) such as a mobile phone or smartphone or multimedia device, an IoT cellular device, a computer with wireless communication capabilities (such as a tablet computer), a personal data or digital assistant (PDA) with wireless communication capabilities, a portable media player, a digital camera, a pocket video camera, a navigation unit with wireless communication capabilities, or any combination thereof. In other embodiments, the user equipment may be replaced by machine communication devices that do not require any human - machine interaction (e.g., sensors, meters, or robots).

[0055] In some embodiments, an apparatus such as a user equipment or a network node may include components for implementing the embodiments described above in connection with Figures 1 to 4 the described embodiments. In certain embodiments, at least one memory including computer program code may be configured to cause the apparatus to perform any of the processes described herein using at least one processor.

[0056] Processors 511 and 521 may be implemented by any computing or data processing device, such as a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), a field programmable gate array (FPGA), a digital enhancement circuit, or similar devices or combinations thereof. The processor may be implemented as a single controller or multiple controllers or processors.

[0057] For firmware or software, the implementation may include units or modules of at least one chipset (e.g., processes, functions, etc.). Memories 512 and 522 may independently be any suitable storage device such as a non-transitory computer-readable medium. A hard disk drive (HDD), random access memory (RAM), flash memory, or other suitable memory may be used. The memory may be incorporated on a single integrated circuit as the processor or may be separate from the processor. Additionally, computer program instructions may be stored in the memory, and the instructions that may be processed by the processor may be any suitable form of computer program code, e.g., compiled or interpreted computer programs written in any suitable programming language. The memory or data storage entity is generally internal but may also be external or a combination thereof, such as in the case of obtaining additional memory capacity from a service provider. The memory may be fixed or removable.

[0058] The memory and the computer program instructions may be configured to cause a hardware apparatus such as network node 520 or UE 510 to perform the processes described above using a processor of the particular device (see, e.g., Figures 1 to 4 ). Thus, in certain embodiments, a non-transitory computer-readable medium may be encoded with computer instructions or one or more computer programs (e.g., added or updated software routines, applets, macro instructions) that, when executed in hardware, may perform a process such as one of the processes described herein. The computer program may be encoded in a programming language, which may be a high-level programming language such as, for example, Objective-C, C, C++, C#, Java, or a low-level programming language such as machine language or an assembler. Alternatively, certain embodiments may be executed entirely in hardware.

[0059] Additionally, although Figure 5A system including network node 520 and UE 510 is shown, but certain embodiments may be applicable to other configurations and configurations involving additional elements, as shown and discussed herein. For example, there may be multiple user devices and multiple base stations, or other nodes providing similar functionality (such as nodes combining the functionality of user devices and base stations (such as relay nodes)). UE 510 may similarly be provided for various configurations for communication other than communicating with network node 520. For example, UE 510 may be configured for device-to-device, machine-to-machine, and vehicle-to-vehicle communication.

[0060] The above embodiments provide significant improvements to the functionality of the network and / or the functionality of network entities in the network or user devices communicating with the network. In certain embodiments, controlling the network access frequency of the UE (such as reattachment or re-registration of the UE to the same network) may help reduce network signaling. The above embodiments may also help prevent the UE from bypassing rate control limits or quotas imposed by the network and ensure a reasonable allocation of network resources to all UEs.

[0061] The features, structures, or characteristics of certain embodiments described throughout this specification may be combined in any suitable manner in one or more embodiments. For example, the use of phrases such as "certain embodiments", "some embodiments", "other embodiments", or other similar language throughout this specification refers to the specific features, structures, or characteristics described in connection with the embodiments that may be included in at least one embodiment of the present invention. Thus, the appearance of phrases such as "in certain embodiments", "in some embodiments", "in other embodiments", or other similar language throughout this specification does not necessarily refer to the same set of embodiments, and the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0062] Those of ordinary skill in the art will readily understand that the present invention discussed above may be implemented by steps in a different order and / or using hardware elements having a configuration different from the disclosed configuration. Thus, although the present invention has been described based on these preferred embodiments, it will be apparent to those skilled in the art that certain modifications, variations, and alternative constructions will be obvious while remaining within the spirit and scope of the present invention. Although the above embodiments mention EPS technology, IoT technology, 4G technology, and 5G technology, the above embodiments may be applied to any 3GPP technology.

[0063] Partial Glossary

[0064] IoT Internet of Things

[0065] UE User Equipment

[0066] PLMN (Public Land Mobile Network)

[0067] 3GPP (3rd Generation Partnership Project)

[0068] EPS (Evolved Packet System)

[0069] MME (Mobility Management Entity)

[0070] 5G (5th Generation)

[0071] RC (Rate Control)

[0072] APN (Access Point Name)

[0073] SPLMN (Service Public Land Mobile Network)

[0074] NAS (Non-Access Stratum)

[0075] RRC (Radio Resource Control)

[0076] TAU (Tracking Area Update)

Claims

1. A method for communication, comprising: sending an initial attachment request message from a user equipment to a network node; receiving from the network node a response indicating that the initial attachment request message is accepted and the user equipment is attached or is being attached to the network, wherein the response includes a backoff timer or an indication of the backoff timer, and wherein the backoff timer includes a duration during which the user equipment is not permitted to re-attach to the network; wherein the duration of the backoff timer starts when the user equipment detaches from the network from an attached state to a detached state; in response to detachment from the network, starting the backoff timer associated with the user equipment; avoiding re-attaching to the network until after the duration of the backoff timer has elapsed; and after the duration of the backoff timer has elapsed, sending another attachment request message from the user equipment to the network node.

2. The method according to claim 1, wherein the backoff timer is pre-configured at the user equipment.

3. The method according to claim 2, wherein when the user equipment receives the indication of the backoff timer from the network node, the start of the pre-configured backoff timer is triggered.

4. The method according to claim 3, wherein when a radio resource control (RRC) connection release message is received, the start of the pre-configured backoff timer is triggered.

5. The method according to claim 1, further comprising: when the user equipment is still attached to the network, transmitting, during at least part of the duration of the backoff timer, a message different from another attachment request from the user equipment to the network.

6. The method according to claim 1, further comprising: avoiding re-attaching to other networks different from the network until after the duration of the backoff timer has elapsed.

7. The method according to claim 1, further comprising: sending an indication included in a re-attachment request message to the network node to indicate high priority; and re-attaching to the network node.

8. A user equipment, comprising: at least one processor; and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured to, using the at least one processor, cause the user equipment to at least perform the process according to any one of claims 1 to 7.

9. A non-transitory computer-readable medium storing instructions which, when executed in the hardware of a user equipment, perform the process according to any one of claims 1 to 7.

10. A user equipment comprising components for performing the process according to any one of claims 1 to 7.

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