JP2017135717A - Method and arrangement for connection re-establishment in telecommunication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a method in user equipment for controlling connection re-establishment between the user equipment and a network; and such user equipment.SOLUTION: The user equipment receives from the network a configuration message defining at least one condition 501; upon detection of connectivity problems to the first cell 503, evaluates the at least one condition 504; and, if the at least one condition is fulfilled for a neighboring cell, applies at least one special criterion for initiating connection re-establishment to the neighboring cell 505, the at least one special criterion being different from at least one criterion that is applied if the at least one condition is not fulfilled.SELECTED DRAWING: Figure 5

Description

  The present invention relates to controlling the start of connection recovery when a connection problem is detected.

  A communication device such as a user equipment (UE) is also called, for example, a mobile terminal, a wireless terminal, and / or a mobile station. User equipment is adapted to communicate wirelessly in a cellular communication network or wireless communication system, sometimes referred to as a cellular wireless system or cellular network. The communication is contained within a cellular communication network, for example between two user equipments, between a user equipment and a regular telephone, and / or with a user equipment and a radio access network (RAN), possibly one or more. This can be done with the server via the core network.

  The user apparatus can also be called a wireless mobile phone, a cellular mobile phone, a notebook computer, or a surface plate having a wireless function, to name just a few examples. The user equipment of the present invention comprises, for example, portable, pocketable, handheld, computer adapted for voice and / or data communication with another entity such as another user equipment or server via RAN Or a vehicle-mounted mobile device. The concept of a user device includes a device having a communication function of mechanical characteristics such as a sensor and a measurement device that do not necessarily interact with the user.

  A cellular communication network covers a geographical area that is divided into cell areas, each cell area depending on the technology and terminology used, eg base stations, sometimes “base stations”, “eNodeB”, “NodeB”. , "B-node", or BTS (transmission / reception base station), which may be referred to as a service, for example, by a radio communication base station (RBS). Base stations are of different types, eg macro eNodeB, home eNodeB, or pico base station, based on communication power and thus on cell size. A cell is a geographic area where wireless communication coverage is provided by a base station at a base station site.

LTE Mobility Mobility management is a difficult task in a cellular communication system, and mobility performance that is functioning correctly for the quality experienced by the end user is extremely important. The Radio Resource Control protocol, RRC (see 3GPP TS36.331) is the main signaling protocol for configuring, reconfiguring and performing standard connection processing for the LTE radio communication access network (E-UTRAN). RRC controls many functions such as connection setup, mobility, measurement, radio communication link failure and connection recovery.

  User equipment in LTE, UE, can be in two RRC states: RRC_CONNECTED and RRC_IDLE. In the RRC_CONNECTED state, mobility is network-controlled based on, for example, measurement values provided by the user equipment. That is, the network determines when and to which cell the user equipment should be handed over based on, for example, a measurement report provided by the user equipment. The network called eNB in E-UTRAN, ie LTE radio communication base station, allows the network to make a decision to hand over the user equipment to a stronger cell when the user equipment moves out of the current cell The various measurement events, thresholds, etc. are configured based on the report that the user device then sends to the network.

    FIG. 1 is a diagram of a simplified signaling scheme for LTE handover, HO procedures. It should be noted that the HO command is actually created in the Target eNB where the user equipment is handed over, i.e. eNodeB, but the message is sent via the Source eNB. That is, the message comes from the Source eNB from the viewpoint of the user apparatus.

  In RRC_IDLE, mobility is handled by UE-based cell selection, where the mobile user equipment selects the “best” cell to stay on, eg based on various specific criteria and parameters transmitted in the cell. To do. For example, different cells or frequency layers can be prioritized with respect to each other so that a user equipment can receive a beacon or pilot measurement quality threshold for a particular cell from some other cell received from another cell. As long as it is better than a beacon or pilot, it tries to stay in that cell.

  The present invention mainly focuses on the above-mentioned network control mobility, that is, the problem related to the LTE user equipment in the RRC_CONNECTED state. Therefore, the problems associated with handover failure are described in more detail below.

In normal circumstances and when the RRC_CONNECTED user equipment moves out of the coverage of the first cell, also called the source cell, before it loses its connection to the first cell, it is also called the target cell, or the second cell. It needs to be handed over to the cell. In other words, it is desirable that the connection be maintained throughout the handover with no or minimal disruption so that the end user is not aware that the handover is taking place. To make this a success,
A measurement report indicating the necessity of mobility is transmitted by the user equipment, which is received by the source eNB,
The Source eNB has enough time to prepare for handover to the target cell (by dividing, by requesting a handover from the Target eNB controlling the target cell),
It is necessary for the user equipment to receive from the network a handover command message created by the Target eNB controlling the target cell and transmitted to the user equipment via the source cell (see FIG. 1).

  In addition, in order for the handover to succeed, the user equipment must eventually succeed in establishing a connection to the target cell, and in LTE, a good random access request in the target cell and subsequent Transmission of the HO complete message from the user apparatus to the Target eNB is requested. It should be noted that the specifications may differ slightly in message naming.

  Thus, in order for a handover to succeed, the sequence of events leading to a good handover is initiated quickly enough so that the radio communication link to the first cell where signaling takes place is reduced before the signaling is completed. Clearly it is necessary not to do too much. In the source cell (ie, the first cell), if the above drop occurs before the handover signaling is completed, the handover is likely to fail. The above handover failure is clearly undesirable. The current RRC specification thus provides various triggers, timers, and thresholds so that the need for handover can be detected reliably and early enough by fully configuring the measurements.

  In FIG. 1, an exemplary measurement report is triggered by a measurement event called an A3 event. In short, the A3 event means that the neighboring cell is better than the current serving cell by an offset. This means that a measurement report is sent to the network when one or more criteria for this event are met. It should be noted that there are many different types of measurement events and there are multiple events that can be configured to trigger reporting.

  A network node controlling the cell, such as the LTE term eNodeB, maintains a neighbor cell relationship list. Whenever reference is made to neighboring cells in the present invention, it should be understood that reference is made to a cell that is normally included in the network node's neighboring cell relationship list. Neighboring cells are therefore often candidate cells for handover. In some cases, the network node maintains a list of neighboring cells for each cell controlled by the network node. From the viewpoint of the user equipment, the neighboring cell is a cell that is close to or overlaps with a cell to which the user equipment is currently connected.

Radio communication link failure and RRC connection recovery User equipment may lose coverage to the cell to which the user equipment is currently connected. This can happen when the user equipment enters a fading dip or when a handover is required as described above but fails due to a handover or for other reasons. This is especially true when the “handover region” is very short, as explained further below.

  The quality of the wireless communication link is typically monitored at the user equipment on the physical layer, as described for example in 3GPP TS 36.300, TS 36.331 and TS 36.133 and summarized below.

  When a physical layer problem is detected according to the criteria defined in TS 36.133, the physical layer sends an indication to the RRC protocol of the detected problem called an asynchronous indication. The timer T310 is started after the number N310 that can be set for the continuous instruction. If the link quality is not improved (recovered) while T310 is being executed, that is, if there is no N311 continuous “synchronization” instruction from the physical layer, the radio communication link failure, RLF is certified in the user equipment (FIG. 2).

  The currently relevant timers and counters described above are described in FIG. 4 for reference. The user equipment can read the timer value and the counter constant from the system information transmitted to the cell. Alternatively, the user equipment is configured with a UE specific value of timer and counter constants using dedicated signaling that is given a specific value and constant to the specific user equipment and the message is directed only to one or more specific user equipment. Is possible.

  The timer and counter functions used to monitor LTE radio communication link failures are presented in the table of FIG.

  When T310 ends, the user equipment starts connection recovery to recover the ongoing RRC connection. This procedure includes cell selection by the user equipment. That is, since the connection with the previous cell based on the described measurement value has failed, the RRC_CONNECTED user equipment autonomously searches for a better cell for connection. The user equipment may return to the first cell for the time being, but the same procedure is performed thereafter. For example, as further described in 3GPP TS 36.304, once a suitable cell is selected, the user equipment requests to restore connectivity in the selected cell. It should be noted that the cell is selected based on the user equipment due to the difference in mobility behavior like RLF, as opposed to the network control mobility that is usually applied.

  If recovery is good, this depends inter alia on the selected cell and whether the eNB controlling the cell is prepared to maintain a connection to the user equipment, which accepts the recovery request However, it is possible to resume the connection between the user apparatus and the eNB. In LTE, the recovery procedure includes a random access request in a selected cell and then higher layer signaling that the user equipment sends a message with content that can identify and authenticate the user equipment based thereon. This is necessary in order for the network to be able to accurately know which user device is trying to perform the recovery.

  The failure of recovery means that the user apparatus enters the RRC_IDLE state and the connection is released. In order to continue communication, a new RRC connection is then requested and determined. For example, the eNB that receives the recovery request may fail if it cannot identify the user equipment that requests the recovery. The above situation may occur when the receiving eNB is not informed about or prepared for possible recovery from this user equipment.

  The reason for introducing the above-described timer T31x and counter N31x is to add some freedom and hysteresis to the reference configuration when the wireless communication link fails and recovery is deemed necessary. This is because the connection is incompletely interrupted and the link quality is temporarily lost and there is no further action or procedure for the user equipment to e.g. before T310 is terminated or before the counter value reaches N310. If the connection can be recovered with this, it will adversely affect the ability of the end user.

The recovery procedure is described below.
A network node such as an eNB controlling the target cell receives a recovery request message from the user apparatus such as an RRC connection recovery request. In response to this message, the target eNB may respond with an RRC connection recovery message sent to the user equipment where the target eNB receives a recovery request. This message may include various configuration parameters so that the connection can be adapted and continued in the new cell. Other message names are of course applicable, for example any reference to cell reselection or handover.

  When receiving the recovery message, the user equipment now processes the content of the message and resumes the RRC connection according to the content and command attached thereto. Usually, the user equipment also sends a confirmation message to the eNB of the target cell indicating that communication between the user equipment and the target eNB can now be resumed. For example, RRC connection recovery requests, recovery messages, and subsequent confirmation messages typically include fields that support positive identification of the user equipment and fields that support conflict resolution, thereby clarifying the user equipment and its connection. Can be reliably identified.

  As a result of the recent rapid adoption of Mobile Broadband, there has been a need to increase the capacity of cellular networks. One solution to increase the capacity is to use a denser network made up of several layers of different sized cells. Macrocells cover a large area of cells, so coverage is surely widened, but micro, pico and even femtocells are deployed in hot spot areas where demand for capacity is high. These cells typically provide connectivity in a fairly small area, but adding additional cells and the radio base station controlling these cells reduces the macro load with new cells. Therefore, the capacity increases. The network is called Heterogeneous Networks, or HetNets. FIG. 9 shows U user equipment E moving from the coverage of picocell A to the coverage of macrocell B.

  Different “layer” cells can be deployed in the same carrier, ie reuse-1 form, small cells can be deployed on different carriers, and even different cells in different layers can be deployed in different technologies, eg non- Limitedly, it can be deployed using 3H / HSPA for macro and micro layers, LTE for pico layers, and the like.

  There is currently a great deal of interest in investigating the possibilities of the above HetNets. However, it has also been found that HetNets can result in a higher handover failure rate, as briefly mentioned above. One reason is that because the handover area of HetNets is very short, that is, before the handover to the target cell can be completed, the handover may fail because the user equipment loses coverage to the source cell. That is. For example, if the user equipment leaves the pico cell, the pico coverage boundary is clear and the user equipment may fail to receive any handover command to the macro before losing coverage to the pico. It can happen (see FIG. 4).

  A similar problem can occur when a user equipment connected to a macro cell suddenly enters a pico cell on the same carrier. Here, the pico control channel may interfere with the signal that the user equipment must receive from the macro to complete the handover, which may cause the handover to fail.

  In the case of a handover failure of the type illustrated above, the user equipment eventually tries to restore the RRC connection. However, this can only occur after the procedure before the recovery procedure is completed, as described above. For this reason, the user equipment observes “asynchronous” of layer 1, L1 to the source cell, and these events are at layer 3, L3 level, ie on RRC as described above, until the N310 above sequence event occurs. It is counted and then T310 is started. Only when T310 is over, the user equipment can start the recovery procedure by searching for a better cell to connect to recover the RRC connection.

  This count (up to N310) and waiting for T310 to end cause undesirable connection interruptions that end users are likely to encounter.

  Thus, it can be said that the network should be configured so that the values of the associated counters and timers (with N310 and T310 as non-limiting examples) are small in order to accelerate recovery. However, this can result in early loss of connectivity when the wireless communication problem is not caused by the most recent handover, but only by a sudden fading dip.

  As a result of the above problems, for example, the handover problem described herein may be suitable for both the more general path loss and the more general case of fading channels where interference varies in a time-dependent manner. It is difficult to find suitable criteria for triggering connection recovery, such as counter and timer values.

  Accordingly, it is an object of embodiments of the present invention to provide a solution that reduces any number of handover failures that an end user will perceive as a connection release.

More specifically, a first aspect of an embodiment of the present invention relates to a user equipment, a method for controlling recovery of connection between the user equipment and a network in a UE, wherein the user equipment is included in the network. A link is established in one cell. The method includes:
-Receiving a configuration message from a network defining at least one condition;
-If a connection problem to the first cell is detected, evaluate said at least one condition;
-At least one criterion applied when the at least one condition is not met for initiating connection recovery to the neighbor cell when the at least one condition is met for the neighbor cell; Applying at least one different special criterion is included.

A second aspect of an embodiment of the present invention relates to a method for controlling connection recovery between a network and a user equipment in a network node to be included in the network, wherein the network is in a first cell included in the network. The user equipment link is established. The method includes:
-Send a configuration message to one or more user equipments defining at least one condition;
-Configuring the one or more user equipments to evaluate the at least one condition when detecting a connection problem to the first cell;
-At least one criterion applied when the at least one condition is not met for initiating recovery of connection to the neighbor cell when the at least one condition is met for the neighbor cell; Comprises configuring the one or more user devices to apply at least one different special criterion.

A third aspect of an embodiment of the present invention relates to a user equipment adapted to control connection recovery between the user equipment and a network, wherein the user equipment has a link in a first cell included in the network. Has been established. User equipment
-A receiver configured to receive a configuration message from a network defining at least one condition;
-A circuit configured to evaluate if at least one condition is met when a connection problem to the first cell is detected, and at least one condition is met for said neighboring cell; The at least one special criterion different from the at least one criterion applied when the at least one condition is not satisfied for initiating the recovery of the connection to the neighboring cell. A processor comprising a circuit.

A fourth aspect of an embodiment of the present invention relates to an arrangement of network nodes that should be included in the network and is adapted to control the recovery of the connection between the network and the user equipment, the network comprising: A user equipment link is established in a first cell included in the network. The arrangement configuration is
-A transmitter configured to send a configuration message to one or more user equipment defining at least one condition;
-Evaluating the at least one condition when detecting a connection problem to the first cell, and restoring the connection to the neighboring cell if the at least one condition is met for the neighboring cell; In order to start, the one or more user equipments are arranged to apply at least one special criterion different from at least one criterion applied if the at least one condition is not met And a processed circuit.

  For this reason, the embodiment is implemented so as to reduce the interruption time in a difficult wireless communication environment in which handover failure is likely to occur. By quickly restoring the connection, all downtime experienced by the end user is reduced. Certain embodiments also reliably increase the likelihood of good connection recovery.

  Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings and claims.

  The foregoing and other objects, features and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments shown in the drawings.

FIG. 3 is a simplified signaling diagram illustrating an LTE handover procedure. It is a figure which shows how the radio | wireless communication link failed and RLF is recognized by LTE. FIG. 3 shows how RLF is monitored in LTE. It is a figure which shows the concept of the handover area | region of pico / macro vs. macro / macro cell change. FIG. 6 is a flow diagram of a method according to an embodiment implemented in a user equipment. FIG. 3 is a flow diagram of a method according to an embodiment implemented in a network node. It is the schematic of the user apparatus by embodiment. It is the schematic of the arrangement configuration of the network node by embodiment. It is a figure which shows U user apparatus E which is moving from the coverage of picocell A to the coverage of macrocell B.

  In the following description, for purposes of explanation, specific details such as specific architectures, interfaces, techniques, etc. are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

  Reference to “an embodiment” or “one embodiment” in the specification refers to a particular feature, structure, or characteristic described in connection with that embodiment, in at least one embodiment of the invention. Means included. The phrases “in one embodiment” or “in one embodiment” in various places in the specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

  The present invention is described in E-UTRAN, also called LTE. It should be understood that the problems and solutions described herein are equally applicable to radio access networks and user equipment, other access technologies and standards being implemented by user equipment. Since LTE is used as an exemplary technique in which the present invention is suitable, the use of LTE in the description is therefore particularly useful for understanding the problem and solutions to solve the problem.

  Various alternative embodiments for carrying out the invention are described below using non-limiting examples.

  Consider a user equipment that is in a connected mode that performs network controlled mobility and is connected to a first cell, eg, a pico cell. It should be noted that the notation “connected to a cell” implies that the user equipment is configured to transmit and / or receive data at least in this cell. Sometimes this cell is also referred to as the “serving cell”, or “primary cell”, PCell. The cell is usually controlled by one network node such as a radio communication base station, and “connected to the cell” in this respect means that the user equipment is “connected to the first radio communication base station”, That is, it means the same as being connected to the radio communication base station controlling the above-mentioned cell. Sometimes this radio communication base station is called Serving eNB or serving radio communication base station.

  In this example, the picocell is “surrounded” by a macrocell that provides coverage in a much larger area as shown in FIG. When the user equipment moves out of the small picocell coverage, it quickly loses the coverage of the currently connected picocell, as shown in FIG. In the above situation, it is more likely that the user equipment loses its connection to the picocell before the handover is completed, which means that the user equipment's wireless communication link has failed and undesired connection interruption as described above. Is caused.

  The same problem can occur when the user equipment moves from a macro cell to another cell, eg, a pico cell with a very short handover area. The problem is further compounded when the user equipment is moving at high speed.

  Embodiments of the present invention provide for the failure of a wireless communication link to fail or only if a certain condition is met for that cell in order to perform connection recovery in that particular neighboring cell. Offers the possibility of bypassing the “normal” evaluation.

  FIG. 5 is a schematic diagram of method steps performed by a user equipment, UE, according to an embodiment of the present invention, wherein the user equipment has a link established in a first cell, in this example a pico cell. Yes. In step 501, the user equipment receives a setup message from the network defining at least one condition to be evaluated by the user equipment when a connection problem to the first cell is detected. The configuration message can be received on a broadcast channel or via dedicated signaling.

  The condition may relate to determining whether the user equipment is within the coverage of any neighboring cell. The evaluation of whether the user equipment is within the coverage of the neighboring cell may be based on whether a signal received from the neighboring cell is stronger than a specific value, for example, a threshold value. Various quality parameters that define the “strength” of the received signal can be implemented, such as measurement of received signal power and path loss related and interference related metrics. This includes, for example, reference symbol received power (RSRP) and reference symbol received quality (RSRQ).

  The network can configure the user equipment to have one or more thresholds that define whether the user equipment should be considered to be within the coverage area of the indicated cell. The network may also configure the user equipment to have quality parameters used by the user equipment when evaluating whether the user equipment is within the coverage area of the indicated cell. For example, if the RSRQ of the indicated cell in the above example is greater than x dB (where x represents a set threshold), then the user equipment determines that it is within the coverage area of that cell. To do.

  If the user equipment identifies that the at least one condition is satisfied for a plurality of neighboring cells, for example, the user equipment is within the coverage of a plurality of cells, prioritize selection among these. There may be additional criteria for doing so. For example, the user equipment can select the best cell, where “best” is defined in terms of the above metrics, for example, the cell with the strongest signal or the best signal quality is selected. The Alternatively, it may be a defined additional priority criterion, such as the relative priority between cells included in the neighbor cell list, or when compared to another cell B or a cell on another frequency layer F_B, If one or more cells are superior by x dB in terms of metrics, for example, an offset defining that cell A or a cell on the frequency layer F_A should be selected.

  As the user equipment moves out of the coverage area of the first cell, in this embodiment the pico cell, the user equipment detects a physical layer problem or other problem related to the connection to the first cell, ie the pico cell. (See step 503). Detection of a physical layer problem may include receiving an asynchronous indication from the physical layer or reading a reference symbol received power, RSRP, or reference symbol received quality, RSRQ below a certain absolute level to the first cell. May be included. The network may configure the user equipment to have one or more thresholds of RSRP or RSRQ that define whether the user equipment should determine that there is a problem with the connection to the source cell. According to another alternative, detecting a connection problem to the first cell includes starting a timer when a measurement event related to the handover is triggered, and the handover performed before the timer expires If not, a connection problem is detected.

  In step 504, the user equipment evaluates whether the at least one condition is met. The condition may relate to determining whether the user equipment is in the coverage of neighboring cells, as already described. Further, as shown below, the evaluation is performed by checking whether one or more specific conditions related to neighboring cells are met. In the above case, the user equipment performs quick connection recovery to the cell by applying one or more special criteria for initiating connection recovery to the cell (see step 505).

  In certain embodiments, the condition is met when the received signal from the neighboring cell is stronger than a threshold.

  According to an alternative embodiment, the condition is met when a measurement event, eg A3, is triggered for the neighboring cell. Alternatively, the condition for a neighboring cell is met if a measurement report is sent to the network indicating that a measurement event has been triggered for the neighboring cell. According to yet another alternative, the condition for the neighboring cell is met if a confirmation of a well-transmitted measurement report is received from the network indicating that a measurement event has been triggered for the neighboring cell.

  An advantage of embodiments where conditions are tied to measurement events already defined for the user equipment is that it is not necessary to define new measurements for the target cell.

  The advantage of the condition being met when the latter two embodiments, i.e. reports are sent and report confirmations are received, is that the user equipment is about to move to a neighboring cell, in this case the target cell. Knowing that the necessary preparations such as the preparation of the target cell can be started. It should be noted that the A3 event is merely an example, and other measurement events can be applied in different embodiments.

  If the at least one condition is met for a neighbor cell, then according to step 505, at least one special criterion is then applied for initiating recovery of connection to the neighbor cell. The special criterion is different from at least one criterion for initiating connection recovery that is applied when the at least one condition is not met.

  If the at least one condition is not met for neighboring cells, the user equipment applies one or more normal criteria (see step 506) to initiate connection recovery, eg, a standard cell selection procedure. In some cases, normal recovery procedures are performed.

  In optional step 507, the user equipment receives from the network an indication of at least one cell to which the at least one special criterion is to be applied if at least one condition is met. The indication may be included in the configuration message received in step 501 in some embodiments.

  The indication of at least one cell provided to the user equipment in step 501 or 507 may be in different forms. According to a particular embodiment, the indication comprises an indication of all neighboring cells of the first cell. In this case, it is not necessary to specifically indicate or point to a specific cell, but is sent from the network to one or more user equipment whenever the at least one specific condition for a quick recovery procedure is met. There is only an instruction that presents the user equipment to apply one or more special criteria that will enable a quick recovery solution.

  According to another particular embodiment, the indication comprises a specific frequency layer indication so that all neighboring cells on the frequency layer are indicated. This is because if at least one condition is met, the user equipment can quickly recover a connection to a cell that is on a specific frequency layer but not on another frequency layer if the at least one condition is met. Means that the solution should be applied. In such a case, since all neighboring cells on a specific frequency layer are indicated by a single instruction, there is no need to indicate a specific cell on the layer.

  According to yet another specific embodiment, the indication includes a list of indicated cells for which the user equipment performs a quick connection recovery if at least one condition is met. If this indication is provided in the form of a list of cells, the cells on the list are identified by cell identifiers, usually the physical cell uniqueness of these cells, PCI, but identify the cells on the list. Other indicators or identification methods for doing so are also applicable. The list may also include an indication of in which frequency layer the cell indicated by the identifier is found.

  The indication provided in step 507 may be provided to the user equipment on the broadcast channel, in LTE terminology, BCCH, or the indication is sent to a particular user equipment or group of user equipment, but all of its cells May be provided by dedicated signaling that is not sent to any user equipment. Broadcast signaling typically implies that one or more messages are sent to some or all user equipment within the coverage of a cell. The message is then often repeated periodically so that the user equipment entering the cell can receive one or more messages at the next opportunity. Dedicated signaling from the network is usually directed to one particular receiver, or group of receivers, by specifically specifying the address of this user device, or group of user devices, in the transmission of the message. Implies that it is. For this reason, the message can be sent only once, and then a confirmation is sent from the receiving user device.

  For the application of one or more criteria to be met to initiate connection recovery, in some embodiments, when the user equipment initiates connection recovery in the indicated cell, a counter for evaluation and / or Or the use of a timer. The counters and / or timers may be the same as those used in the “normal” recovery procedure. For example, the network configures the user equipment to have a counter value N310 equal to 10 and a timer end value T310 equal to 500 milliseconds. The recovery of the “normal” connection is then started after ten consecutive “asynchronous” indications, and then the start and end of timer T310, ie a waiting time of 0.5 seconds, occurs. Only then does the user equipment select a cell in which the user equipment will implement a recovery request.

  According to a particular embodiment, recovery is started for a cell as soon as the at least one condition is satisfied for a neighboring cell. This means that recovery is started as soon as the at least one condition is met, i.e. without applying additional criteria to start connection recovery. The above embodiments will be described using the following non-limiting examples.

  The user equipment is configured by the network to initiate recovery of the connection to a particular neighbor cell when it detects a connection problem to that serving cell when an A3 event is triggered for that neighbor cell. . Suppose a connectivity problem is detected by receiving an asynchronous indication from the physical layer. According to this particular embodiment, the user equipment then stops the counter N310 counting asynchronous instructions from the physical layer, or the timer T310 controlling the failure of the radio communication link, and the A3 event is: Immediately initiates recovery of the connection to the neighboring cell being triggered towards the target cell.

  In an exemplary alternative embodiment, the at least one special criterion includes an end of a timer at a specific end value, wherein the end value is different from the end value of the timer applied to “normal” connection recovery. I.e., if the at least one condition is not met and / or a counter threshold is reached, the threshold is set if the at least one condition is not met, i.e. for normal connection recovery This is different from the timer end value applied to. Accordingly, the user device can execute and use different values of timers and / or counters for evaluation when the user device initiates connection recovery when the at least one condition is met.

  For this reason, according to an embodiment of the present invention, the user equipment may, according to a “normal” connection recovery procedure, before a timer and, for example, a T310 count and end is determined, if at least one condition is met. Recovery of the RRC connection to the neighboring cell can be performed.

  For example, the threshold value of the counter is set to 3 as a special criterion, whereby the special criterion is that the user equipment starts recovery to a neighboring cell where the at least one condition is met after 3 “asynchronous” indications. It implies that you can. Alternatively, or in addition, the timer end value is set to 100 milliseconds as another special criterion so that the user equipment can recover to a neighboring cell that satisfies the at least one condition 100 milliseconds after the start of T310. Can start.

  In another alternative embodiment, the at least one special criterion includes at least one different counter and / or timer in addition to at least one counter and / or timer used to initiate “normal” connection recovery. The different counters and / or timers will be managed when usage is included and the user equipment is able to initiate recovery of the connection to the cell where the condition is met. For example, the start of recovery in a cell for which the condition is met may be associated with a counter value 3 of counter N410 and a timer value “100 milliseconds” of timer “T410”. The naming of timers and counters should be seen as examples only and does not imply any limitation on the applicability of embodiments of the present invention. The same counter “N410” and timer “T410” can be used to manage recovery to all neighboring cells. There may be separate values for the counters and timers for each neighbor cell or group of neighbor cells.

  Many variations and combinations are possible. The counter and timer values to evaluate when the user equipment attempts to restore the connection to the neighbor cell are subject to several implementations, both when at least one condition is met or not met. In form, it can be configured by a network (see optional step 502 in FIG. 5 and step 603 in FIG. 6).

  In an embodiment of the present invention, the user equipment is configured to have at least one condition for evaluating to determine whether the user equipment should perform a quick connection recovery procedure to a specific neighboring cell. Network aspects for doing so are also included. On the network side, the principle of providing one user equipment or a group of user equipment with the above-mentioned at least one condition to be evaluated upon detection of the first, i.e. connection problem with the serving cell is That is particularly difficult. For this reason, in a specific area, it is often necessary to rely on connection recovery initiated by the user equipment. Therefore, there is an incentive to increase the speed of recovery where the above problem can occur.

  FIG. 6 is a schematic diagram of method steps performed by a network node according to an embodiment of the present invention. In step 602, the network node sends a setup message defining at least one condition to one or more user equipments that have established links in the first cell controlled by the network node. Examples of the conditions are those described above in connection with the description of the method implemented by the user equipment. In step 605, the one or more user equipments are configured by the network node to evaluate the at least one condition when detecting a connection problem to the first cell. In step 606, the one or more user equipments apply at least one special criterion for initiating recovery of connections to neighboring cells when the at least one condition is met for the neighboring cells. The special criterion is different from at least one criterion applied when the at least one condition is not satisfied.

  In optional step 607, the network node sends an indication of at least one cell to which the at least one special criterion for initiating connection recovery is applied if the at least one condition is met. The indication of at least one cell may be in the different form described above in connection with the description of the method implemented by the user equipment.

  In optional step 600, the network node receives information from one or more neighboring network nodes about previous recovery requests to determine which cells should be directed to one or more user equipments in step 607. To do. Thus, the network uses, for example, statistics from previous handover failures in order to determine which neighboring cell to indicate. For example, in the eNB, if there is information that the handover from eNB cell A to cell B often fails, the network should perform quick connection recovery by the user equipment applying the at least one special criterion Cell B can be added as the indicated cell. For example, information such as a handover failure can be received from an adjacent network node via, for example, an X2, S1, or Q & M interface.

  The network node can thus be arranged to collect information about connection problems, such as failure of handover, for example, and to provide this information to other eNBs controlling neighboring cells. For example, the network node B controlling the cell B finds that the user equipment often reaches this cell after the handover from the cell A fails (see FIG. 9). The network node B controlling the cell B can receive this information in the RLF report message (see 3GPP TS 36.331), and the information element can be a failedPCellId. Network node B collects this information and sends it to network node A controlling cell A, either directly or via some collective node, for example a Q & M node, so that the network node is quick to the user equipment. Cell B can be added as an instructed cell to perform recovery.

  In optional step 601, the network node determines which cell to send to the user equipment, which is sent in step 607. This can be done by using information or statistics of previous connection problems that are received from neighboring network nodes as described above or that are themselves available.

  In step 604, which is an optional step related to a particular embodiment, the network is at least one second network node controlling the indicated cell, eg a radio communication base station, or eNodeB in LTE terminology. In step 607 to prepare the neighboring cell indicated to one or more user equipment, so that the second network node from the particular user equipment currently connected to the first cell. Be prepared to receive a connection recovery request. This preparation may include sending a handover request from the first network node to the second network node. If both cells are controlled by the same network node, there is no need to send a message, but the network node itself can be prepared to restore the connection from UE1 in the indicated cell.

  Alternatively, if the prepare message is not sent, the second network node controlling the indicated cell does not receive any information regarding all user equipment that may request connection recovery in the indicated cell. Therefore, the second network node does not own the context of all user equipments associated with the user equipment. The second network node that controls the indicated cell can then fetch the context of the user equipment from the network node that controls the first cell. The fetch implies that the second network node requests information about the user equipment from the first network node when detecting a recovery request from the user equipment. If the second network node receives the necessary information about the user equipment to accept the recovery request, the fetch is good. When the fetch is good, the second network node can accept recovery from the user equipment.

  A user equipment 700, UE according to an embodiment of the present invention is schematically illustrated in FIG. The user device includes a receiver 702 and a transmitter 703. The receiver is configured to receive a configuration message from a network that defines at least one condition. Examples of the above conditions have been described above in connection with the description of the method implemented by the user equipment. The message can be received on a broadcast channel or via dedicated signaling.

  The user equipment 700 further includes a processing circuit configured to evaluate if the at least one condition is satisfied when a connection problem to the first cell is detected, and the at least one for neighboring cells. Said at least one special that differs from at least one criterion applied when said at least one condition is not met to initiate a recovery of connection to said neighboring cell when one condition is met A processor 701 comprising circuitry configured to apply the reference.

  In some embodiments, the user device 700 further comprises a timer 704 and / or a counter 706. In certain embodiments, the at least one special criterion includes an end of a timer 704 at a specific end value, the end value being when the at least one condition is not met and / or of the counter 706. Unlike the end value of the timer 704 that is applied when the threshold is reached, the threshold is different from the threshold of the counter 706 that is applied when the at least one condition is not satisfied. In certain embodiments, timer 704 may be timer T310 and counter 706 may be counter N310.

  In yet another embodiment, the user equipment 700 may use a neighbor cell in addition to the counter 706 and / or timer 704 used to initiate recovery to the cell if the at least one condition is not met. Another different counter 707 and / or timer 705 is provided to initiate the recovery of the connection to.

  An arrangement configuration in the network node 800 is schematically shown in FIG. The network node is adapted to be included in the network and is further adapted to control the recovery of the connection between the network and the user equipment, the UE, the network being in a first cell included in the network The user equipment link is established.

  The arrangement configuration includes a receiver 802 and a transmitter 803. The transmitter 803 is configured to send a configuration message to one or more user devices that define at least one condition. Examples of the above conditions have been described in connection with the description of the method embodiments implemented by the user equipment. The message can be sent on a broadcast channel or via dedicated signaling.

  The arrangement in the network node 800 further includes a processing circuit arranged to configure the one or more user devices to evaluate the at least one condition when detecting a connection problem to the first cell. Including a processor (801). The processing circuit is further applied when the at least one condition is not satisfied to initiate recovery of connection to the adjacent cell when the at least one condition is satisfied for the adjacent cell. The one or more user devices are arranged to apply at least one special criterion different from the at least one criterion.

  In an embodiment, the transmitter 803 sends an indication of at least one cell to which the at least one special criterion is applied to initiate connection recovery when the at least one condition is met. Composed. The indication of the at least one cell may be in a different form as described above in connection with the description of the method implemented by the user equipment.

  In an embodiment, the receiver 802 receives information about previous recovery requests from one or more neighboring network nodes to determine which at least one cell should be directed to one or more user equipments. Configured as follows.

  In some embodiments, the processor (801) comprises circuitry configured to use information of previous connection problems to determine which cells should be directed to one or more user equipments. The processing circuitry is also configured to use information or statistics about a recovery request received by the receiver (802) from a neighboring network node to determine which cell to indicate to one or more user equipments. Can be done.

  In an embodiment, the transmitter (803) can be configured to send a prepare message to at least one neighboring network node controlling at least one cell indicated to the one or more user equipments. This prepares the network node to receive a connection recovery request from the one or more user equipments.

  The method steps performed by the user equipment (700) and the arrangement of the network nodes (800) are performed by the functional elements of the processing circuits of the processors 701 and 801. In certain embodiments, these functions may be combined with other digital hardware, which may include a suitably programmed microprocessor, or microcontroller alone, or may include a digital signal processor (DSP), special purpose digital logic, etc. Done. Either or both of the microprocessor and digital hardware can be configured to execute program code stored in memory. Again, the various details and engineering trade-offs associated with the design of mobile device and baseband processing circuitry for wireless communication base stations are well known and are not necessary for a complete understanding of the present invention. Further details are not described herein.

  The program code stored in the memory circuit may comprise one or several types of memory such as read only memory (ROM), random access memory, cache memory, flash memory device, optical storage device, etc. Or a plurality of telecommunication and / or data communication protocols, and in some embodiments, program instructions for executing instructions for performing one or more of the techniques described herein. Of course, not all of these technology steps are performed in a single microprocessor or module.

  The present invention may, of course, be carried out in other ways than those specifically set forth herein without departing from essential characteristics of the invention. The embodiments of the present invention should be considered as illustrative in all aspects and not limiting.

Claims (41)

In a user equipment, UE (700) served in a first cell (A) included in a network, a method for controlling recovery of a connection between the user equipment and the network, the following steps:
-Receiving (501) a configuration message from the network defining at least one condition;
-Evaluating (504) the at least one condition upon detecting (503) a connection problem to the first cell;
-If said at least one condition is met for a neighbor cell (B), at least applied if said at least one condition is not fulfilled in order to initiate a recovery of connection to said neighbor cell Applying (505) at least one special criterion different from the one criterion.   The method according to claim 1, wherein the at least one condition is related to determining whether the user equipment is within the coverage of the neighboring cell (B).   The method according to claim 2, wherein a condition is satisfied for the neighboring cell (B) if a signal received from the neighboring cell (B) is stronger than a threshold.   The method according to claim 2 or 3, wherein a condition is met if a measurement event is triggered for the neighboring cell (B).   The method according to claim 2, wherein a condition is met for the neighbor cell when a measurement report is sent to the network indicating that a measurement event has been triggered for the neighbor cell (B).   The condition is satisfied for the neighbor cell when a confirmation is received from the network that a measurement report indicating that a measurement event has been triggered for the neighbor cell (B) has been successfully transmitted. The method described in 1.   Receiving a message from the network including an indication of at least one neighboring cell (B) to which the at least one special criterion is applied to initiate connection recovery if the at least one condition is met The method of any one of claims 1 to 6, comprising the step of (507).   8. A method according to any one of the preceding claims, wherein recovery is started immediately when the at least one condition is met.   The at least one special criterion includes an end of a timer (704) at a specific end value, wherein the end value is an end value of the timer (704) that is applied when the at least one condition is not met. The method according to claim 1, which is different from   The at least one special criterion includes reaching a threshold value of the counter (706), which is different from the threshold value of the counter (706) that is applied when the at least one condition is not met. 10. A method according to any one of claims 1 to 7 and 9.   The at least one special criterion includes a counter (706) and / or timer (704) used to initiate recovery if the at least one condition is not met, in addition to a connection to a neighboring cell. 11. A method according to any one of claims 1 to 7 and 9 to 10, comprising using a counter (707) and / or a timer (705) to assess when to start recovery. Controls recovery of connection between the network and the user equipment in the network node (800) to be included in the network serving the user equipment (700) in the first cell (A) included in the network The following steps:
-Sending (602) a setup message to one or more user equipments defining at least one condition;
Configuring (605) the one or more user equipments to evaluate the at least one condition upon detecting a connection problem to the first cell;
-When said at least one condition is not satisfied in order to initiate recovery of connection to said adjacent cell (B) when said at least one condition is satisfied for neighboring cell (B); Configuring (606) the one or more user devices to apply at least one special criterion different from the applied at least one criterion.   The method according to claim 12, wherein the at least one condition relates to determining whether a user equipment is within the coverage of the neighboring cell (B).   The method according to claim 13, wherein a condition is satisfied for the neighboring cell (B) if a signal received from the neighboring cell (B) is stronger than a threshold.   15. A method according to claim 13 or 14, wherein a condition is met when a measurement event is triggered for the neighboring cell.   The method according to claim 13, wherein a condition is met for the neighboring cell when a measurement report is sent to the network indicating that a measurement event has been triggered for the neighboring cell (B).   The condition is satisfied for the neighbor cell when a confirmation is received from the network that a measurement report indicating that a measurement event has been triggered for the neighbor cell (B) has been successfully transmitted. 14. The method according to 13.   If the at least one condition is met, sending (607) an indication of at least one cell to which the at least one special criterion is applied to one or more user equipments to initiate connection recovery (607); 18. A method according to any one of claims 12 to 17 comprising.   19. The method of claim 18, wherein the network node uses information on previous connection problems to determine (601) which cells to indicate to the one or more user equipments.   19. The network node receives information about a previous recovery request from a neighboring network node (600) to determine (601) which cell to indicate to the one or more user equipments. 19. The method according to 19.   The network node sends a preparation message to at least one network node that controls at least one cell indicated by the message to the one or more user equipments (604), and the one or more network nodes are sent to the network node. 21. A method according to any one of claims 18 to 20, wherein the method prepares to receive a connection recovery request from the user equipment (700) of the user. Said user equipment (700) adapted to control recovery of a connection between a user equipment and a network, said user equipment being served in a first cell (A) comprised in said network ,
A receiver (702) configured to receive (501) a configuration message from the network defining at least one condition;
-Configured to evaluate whether the at least one condition is met when detecting a connection problem to the first cell, and the at least one condition is met for a neighboring cell (B); In order to apply at least one special criterion different from at least one criterion applied when the at least one condition is not satisfied to initiate a recovery of connection to the neighboring cell. A user equipment (700) comprising: a processor (701) comprising a configured circuit.   The user equipment (700) according to claim 22, wherein the at least one condition relates to determining whether the user equipment is within the coverage of the neighboring cell (B).   The user equipment (700) according to claim 23, wherein a condition is satisfied for the neighboring cell when a signal received from the neighboring cell (B) is stronger than a threshold.   25. User equipment (700) according to claim 23 or 24, wherein a condition is fulfilled when a measurement event is triggered for the neighboring cell (B).   24. User equipment (700) according to claim 23, wherein a condition is met for the neighboring cell when a measurement report is sent to the network indicating that a measurement event has been triggered for the neighboring cell (B). ).   24. The condition is satisfied for the neighbor cell when a confirmation is received from the network that a measurement report indicating that a measurement event has been triggered for the neighbor cell (B) has been successfully transmitted. A user device (700) according to claim 1.   The receiver (702) further receives an indication of at least one cell (B) to which the at least one special criterion is applied to initiate connection recovery when the at least one condition is met. 28. A user device (700) according to any one of claims 22 to 27, configured to (507).   A timer (704), wherein the at least one special criterion comprises an end of the timer at a specific end value different from the end value of the timer applied if the at least one condition is not met, A user device (700) according to any one of claims 22 to 28.   Comprising a counter (706), the at least one special criterion comprising reaching a counter threshold different from the counter threshold applied when the at least one condition is not met. 30. A user device (700) according to any one of 22 to 29.   In addition to the counter (706) and / or timer (704) used to evaluate when the at least one condition is not met, the recovery to neighboring cells starts. 31. A counter (707) and / or a timer (705) for evaluating when to initiate a recovery of a connection to a neighboring cell if is satisfied. User device (700). To be included in the network, adapted to control the recovery of a connection between the network and the user equipment serving the user equipment (700) in a first cell (A) included in the network An arrangement configuration of the network node (800),
-A transmitter (803) configured to send a setup message (602) to one or more user equipment defining at least one condition;
-Evaluating the at least one condition when detecting a connection problem to the first cell and recovering the connection to the neighboring cell if the at least one condition is met for the neighboring cell; To start, the one or more user devices are configured to apply at least one special criterion different from the at least one criterion applied if the at least one condition is not met (605, 606) an arrangement configuration of the network node (800), comprising a processor (801) having a processing circuit arranged as described above.   The arrangement of claim 32, wherein the at least one condition relates to determining whether a user equipment (700) is within the coverage of the neighboring cell.   34. The arrangement according to claim 33, wherein a condition is satisfied for the neighboring cell when a signal received from the neighboring cell (B) is stronger than a threshold value.   35. Arrangement according to claim 33 or 34, wherein a condition is fulfilled when a measurement event is triggered for the neighboring cell (B).   34. The arrangement according to claim 33, wherein a condition is met for the neighboring cell when a measurement report is sent to the network indicating that a measurement event has been triggered for the neighboring cell (B).   34. A condition is satisfied for the neighbor cell when a confirmation is received from the network that a measurement report indicating that a measurement event has been triggered for the neighbor cell (A) has been successfully transmitted. The arrangement configuration described in 1.   If the at least one condition is met, an indication of at least one cell to which the at least one special criterion is applied to initiate connection recovery is sent to one or more user equipments (700) ( 607) Arrangement according to any one of claims 32 to 37, comprising a transmitter (803) configured as described above.   39. The processing circuit of claim 38, comprising processing circuitry configured to determine (601) which cells to indicate to the one or more user equipments (700) using information on previous connection problems. Arrangement configuration.   A receiver (802) configured to receive information about a recovery request from an adjacent network node (600) and determine (601) which cell to indicate to one or more user equipments (700) 40. An arrangement according to claim 38 or 39, comprising:   The transmitter (803) sends a preparation message (604) to at least one network node controlling at least one cell indicated by the message, and the one or more user devices are sent to the network node. 41. An arrangement according to any one of claims 38 to 40, arranged to prepare to receive a connection recovery request from.

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