JP7097797B2 - Automatic connection switching in wireless communication network - Google Patents

Description

The present invention relates to a method of managing a connection between a user terminal and a wireless communication network and to a corresponding device.

Handover (HO) that allows an ongoing user terminal (UE) connection to be maintained on the move between different serving cells, for example to a cellular network as specified by 3GPP (3rd Generation Partnership Project). ) The procedure is defined.

For example, in the case of LTE (Long Term Evolution) technology, such a HO procedure is specified in 3GG TS36.331 V12.0.0 (January 2014). In these HO procedures, a UE that is in a state called "RRC_connected", i.e., having an active connection to the cellular network, typically monitors a set of adjacent cells. These measurements can trigger the transmission of a measurement report from a UE to a serving base station of that UE, called eNB (Evolved NodeB) in LTE technology. A typical example of such a trigger event, called "event A3", is that the measurement result corresponding to a better adjacent cell measurement result than the current serving cell with an offset is, for example, the reference signal received power ( Can be expressed in terms of RSRP) or reference signal reception quality (RSRQ). The trigger event further requires that such a condition be met for a predetermined minimum period specified by a parameter called "timeToTagger". Based on the measurement report, the serving eNB determines whether or not to perform the HO of the UE. If it decides to perform the HO of the UE, the serving eNB prepares the HO by sending a HO request to the eNB that controls the target cell for the HO. The serving eNB also provides the context information of the UE as part of this HO request, eg, with respect to the current access hierarchy (AS) settings and UE-specific radio resource management (RRM) information. Accordingly, the eNB that controls the target cell generates a HO command. Then, the serving eNB transfers the HO command to the UE. This is done in a transparent manner, i.e., the information provided to the UE is determined by the eNB that controls the target cell and is not modified by the serving eNB. The HO command sent to the UE is, for example, the identity of the target cell and optionally the frequency and random access, individual radio resource settings, security settings, or cell-specific radio network temporary identity (C-RNTI) to be used in the target cell. ), Etc., which includes RRC information common to all UEs in the target cell. With such information, the UE can then continue by performing random access to the target cell. If the random access is successful, the UE then confirms the successful completion of the HO to the eNB that controls the target cell, which will be the new serving cell for the UE.

In some scenarios, the network-initiated HO may be performed without previous event A3 and measurement reports from the UE. In such a case, the UE does not know the target cell before receiving the HO command from the serving eNB.

As will be appreciated, the known HO procedures described above require unnecessarily complex interactions between the serving eNB, the eNB controlling the target cell, and the UE, which makes such a HO time consuming. sell.

To meet future demands on wireless communication networks, a network arrangement called Ultra High Density Network (UDN) is being discussed (for example, Ericsson's White Paper "5G Wireless Access" published on the Internet in June 2013. See). For such UDNs, use a large number of densely populated access points (APs), and for example higher bandwidth and higher frequency bands in LTE technology, such as hundreds of MHz or GHz range. It has been suggested to utilize bandwidths up to and frequency bands in the range of 10-100 GHz.

A typical application scenario for a UDN deployment is within a densely populated area, such as a hotspot, office building, or city center, where there may be a demand for high data rate services.

However, for UDN arrangements in such high frequency bands, weak scattering and diffraction can cause a large attenuation difference between the NLOS (non-line-of-sight) radio link and the LOS (line-of-sight) radio link. As a result, there can be numerous areas, i.e., radio coverage holes, with weak signal levels or sudden signal outages. Therefore, the existing concept of mobility may not be appropriate for such an arrangement. For example, higher density APs can result in excessive amounts of HO procedures and unacceptable signaling overhead or service degradation. In addition, sudden signal outages also have the effect of not being able to perform the HO procedures initiated by traditional networks as described above, as signal outages prevent the UE from sending measurement reports or receiving HO commands, for example. Can have.

Therefore, there is a need for techniques that enable the effective management of UE connections to wireless communication networks.

According to an embodiment of the present invention, there is provided a method of managing the connection between the UE and the wireless communication network. According to this method, the access point of the communication network provides a connection to the UE. The access point determines multiple target access points. In addition, the access point sends a message to the UE. The message indicates multiple target access points and allows the UE to automatically switch connections to one or more of the target access points.

A further embodiment of the invention provides a method of managing the connection between the UE and the wireless communication network. According to this method, the UE receives a message from the access point of the communication network that provides the connection to the wireless communication network of the UE. The message indicates multiple target access points and allows the UE to automatically switch to one or more of the indicated target access points. According to this method, the UE further detects a trigger event. Upon detecting a trigger event, the UE switches the connection to one or more of the target access points.

A further embodiment of the invention provides an access point for a wireless communication network. The access point has a wireless interface to provide a connection to the UE. Further, the access point has at least one processor. At least one processor is configured to determine multiple target access points. In addition, at least one processor is configured to send a message to the UE. The message indicates multiple target access points and allows the UE to automatically switch connections to one or more of the target access points.

According to a further embodiment of the invention, a UE is provided. The UE has a wireless interface for establishing a connection to a wireless communication network. Further, the UE has at least one processor. At least one processor is configured to receive a message from a communication network access point that currently provides a connection to the UE's wireless communication network. The message indicates multiple target access points and allows the UE to automatically switch to one or more of the indicated target access points. Further, at least one processor is configured to detect a trigger event and switch connections to one or more of the target access points in response to the detection of the trigger event.

According to a further embodiment of the invention, a computer program or computer program product comprising program code to be executed by at least one processor of an access point for a wireless communication network, for example in the form of a non-temporary storage medium. Provided. Execution of the program code causes at least one processor to determine multiple target access points. Further, the execution of the program code causes at least one processor to send a message to the UE. The message indicates multiple target access points and allows the UE to automatically switch connections to one or more of the target access points.

A further embodiment of the invention provides a computer program or computer program product containing program code to be executed by at least one processor of the UE, for example in the form of a non-temporary storage medium. Execution of the program code causes at least one processor to receive a message from a communication network access point that currently provides a connection to the UE's wireless communication network. The message indicates multiple target access points and allows the UE to automatically switch to one or more of the indicated target access points. Further, the execution of the program code causes at least one processor to detect the trigger event and switch the connection to one or more of the target access points in response to the detection of the trigger event.

The figure which shows schematic the network arrangement for performing the automatic connection switching by embodiment of this invention. The signaling diagram which shows the exemplary connection switching procedure by embodiment of this invention. FIG. 6 is a signaling diagram illustrating a further exemplary connection switching procedure according to an embodiment of the present invention. The flowchart for demonstrating the method by Embodiment of this invention which can be used to perform the function of connection switching by Embodiment of this invention in an access point. A flowchart illustrating a method according to an embodiment of the present invention, which can be used to perform a connection switching function according to the embodiment of the present invention in a UE. The figure which shows schematic structure of the example of the access point by embodiment of this invention. The figure which shows schematic structure of an exemplary UE by embodiment of this invention.

Hereinafter, the concept according to the embodiment of the present invention will be described in detail with reference to the accompanying drawings. The concept described relates to the management of connection switching in wireless communication networks. In the embodiments described, it is assumed that the wireless communication network is based on a UDN arrangement. Specifically, the wireless communication network may use closely spaced access points, for example, with a distance between adjacent access points in the range of 1 m to 1000 m, typically in the range of 2 m to 500 m. In addition, the access point can operate in the radio frequency band between 10 GHz and 100 GHz, which means that there can be a sufficient difference in link quality between the LOS link and the NLOS link. However, the concepts described can be applied in corresponding ways to other radio technologies such as LTE, UMTS (Universal Terrestrial Telecommunications) or CDMA (Code Division Multiple Access), or CDMA2000. Deafness should be understood.

FIG. 1 schematically shows the structure of a wireless communication network and an exemplary UE 50. Specifically, FIG. 1 shows a plurality of access points 100-1, 100-2, 100-3, 100-4 of a wireless communication network that can be used to connect to the wireless communication network by the UE 50. .. Here, for the connection between the UE 50 and the wireless communication network, appropriate access points 100-1, 100-2, 100-3, 100-4 are selected, and the UE 50 and the access points 100-1, 100-2 are selected. , 100-3, can be formed by setting a radio link between 100-4. In the exemplary scenario shown in FIG. 1, the connection is formed by a wireless link to access point 100-1. The access point 100-1 that maintains an active connection between the UE 50 and the wireless communication network may also be referred to as the serving access point of the UE 50. In some cases, the connection may utilize multiple wireless links to different access points 100-1, 100-2, 100-3, 100-4 and then coordinately serve the UE 50. sell.

As described above, the wireless communication network may utilize a high frequency band in the range of 10 GHz to 100 GHz, specifically a frequency band above 30 GHz, such as in the range of about 60 GHz. This frequency domain above 30 GHz is also called the MMW (millimeter wave) band.

In such a high frequency band, relatively large radio attenuation and relatively low radio diffraction have the effect that the LOS radio link will usually have significantly better quality than the NLOS radio link. However, because LOS radio links are sensitive to propagation obstacles, fast switching between different access points 100-1, 100-2, 100-3, 100-4 is required to maintain the connection. It is possible. For example, due to the movement of the UE 50, an obstacle affects the LOS radio link to access point 100-1, which requires switching the connection to another access point 100-2, 100-3, 100-4. Means that you are. Similar effects can occur if a person moves to a mobile propagation obstacle, eg, the LOS between the UE 50 and the current serving access point 100-1. Since the transition from the LOS condition to the NLOS condition can occur suddenly, there is a risk of sudden failure of the radio link to the current serving access point 100-1. This may have the effect that the UE 50 cannot subsequently report measurements to the serving access point 100-1, and the serving access point 100-1 cannot send control commands to the UE 50. Therefore, conventional HO procedures, such as those described in 3GPP TS36.331, may not be applicable in these environments.

According to a concept as further described below, between access points 100-1, 100-2, 100-3, 100-4 in a manner that the UE 50 can automatically execute for the above situations. It can be dealt with by managing the switching of. To this end, the current serving access point 100-1 actively messages to the UE 50 to allow the UE 50 to automatically switch the connection to one or more target access points indicated in the message. Can be sent. Therefore, while overall management of connections is still network-based, the actual switching process can be performed automatically by the UE 50. Hereinafter, the above-mentioned message is also referred to as a switching permission message. The switch permission message may be sent early before the connection to another access point needs to be switched and while the connection to the current serving access point 100-1 is still intact. The switch permission message may also contain information about different indicated target access points that should be used by the UE 50 in switching the connection to those target access points. For example, such information may include settings such as target access point settings, switching conditions, available radio resources, and settings that the UE 50 should use to access the target access point. The UE 50 can then determine when and when to perform the switch and may select the most appropriate target access point from the indicated target access points. This is accomplished in an automated manner, i.e., without requiring further interaction between the UE 50 and the current serving access point 100-1. Therefore, it is possible to switch the connection at high speed in the situation where the wireless link to the current serving access point 100-1 does not work. In this way, the concepts described may be able to avoid interruption of service due to a complete failure of the ongoing connection.

Various conditions can be evaluated by the current serving access point to trigger the transmission of the switch permission message. For example, the current serving access point may perform measurements and trigger the transmission of a switch permission message in response to these measurements. Such measurements may relate, for example, to the quality of the radio link between the UE 50 and the current serving access point 100-1 or the speed at which the UE 50 travels.

FIG. 2 further illustrates the above concept by reference to an exemplary procedure for switching the connection from the current serving access point 100-1 of the UE 50 to another access point 100-2.

In the procedure of FIG. 2, in step 201, the connection between the UE 50 and the wireless communication network is established. As described, the connection is established by setting up a wireless link between the UE 50 and the access point 100-1. Therefore, the access point 100-1 becomes a serving access point for the UE 50.

In step 202, the access point 100-1 detects the trigger event. The trigger event may correspond, for example, to establishing a connection in step 201. Further, the trigger event may be based on at least one of predetermined measurements and evaluations performed by access point 100-1. For example, access point 100-1 measures and evaluates the quality of the radio link between UE 50 and access point 100-1 in terms of, for example, a channel quality indicator, beacon power level, or achievable bit rate. Can be possible. The trigger event can then correspond to the quality of the radio link below a given threshold value. Further, the access point 100-1 can determine the probability of failure of the radio link between the UE 50 and the access point 100-1. For example, this can be accomplished based on radio coverage hole statistics in the radio coverage area of access point 100-1 and information on the location or movement of the UE 50. Further, the access point 100-1 can measure the speed of the UE 50, for example by evaluating the radio signal transmitted by the UE 50, and the trigger event is the speed of the UE 50 exceeding a given threshold value. Can correspond to. In this case, it may be considered that a UE that is moving at high speed is more likely to request a switch to another access point than a UE that is moving at low speed or is stationary. Further, the access point 100-1 evaluates whether the switch permission message previously sent to the UE 50 is valid or expired, and when the switch permission message previously transmitted is no longer valid, the switch permission message is used. Can trigger the transmission of. This can be accomplished, for example, by providing a timer that is reset when the access point 100-1 sends a new switch permission message to the UE 50 and using the expiration of that timer as a trigger event.

In step 203, the access point 100-1 determines a plurality of target access points constituting the destination candidates capable of switching the connection between the UE 50 and the wireless communication network. In the illustrated procedure described, it is assumed that these target access points are access points 100-2 and 100-3. The access point 100-1 may apply various criteria for determining the target access points 100-2 and 100-3. For example, the access point 100-1 may select an access point located in the travel direction of the UE 50, or an access point that provides radio coverage in a known coverage hole of the radio within the coverage area of the access point 100-1.

The access point 100-1 then sends a switching permission message 204 to the UE 50. This can be accomplished via a control channel supported by a radio link between the UE 50 and the access point 100-1. The switching permission message indicates the target access points 100-2 and 100-3 determined in step 203. Further, the switch permission message 204 indicates the target access point 100-2, which is indicated in the switch permission message 204, without requiring further communication between the UE 50 and the access point 100-1 for the connection that the UE 50 is continuing. Allows automatic switching to one or more of 100-3.

The switch permission message 204 may carry various types of information that can be used by the UE 50 to perform automatic switch switching of connections. For example, the switch permission message 204 may indicate one or more conditions for triggering a switch in the UE 50. Such a condition indicates, for example, that the expected radio link quality of one of the target access points 100-2, 100-3 exceeds the radio link quality of the current serving access point 100-1 by a given amount. , Corresponds to the measurements made by the UE 50. Further, under such a condition, the radio link quality of the current serving access point 100-1 is below the first threshold value, and the expected radio link quality of one of the target access points 100-2 and 100-3 is the second. Can correspond to measurements made by the UE 50 that indicate above the threshold of. As a further example, such conditions may correspond to a failure of the radio link or interruption of connection to the current serving access point 100-1.

Further, the switch permission message 204 may indicate information about each of the indicated target access points 100-2 and 100-3. For example, such information may include the identities of target access points 100-2, 100-3, eg, in terms of indexes. Further, such information may include at least one of the sequence, timing, and radio resources used for the beacon or pilot signal transmitted by the target access points 100-2, 100-3. In addition, it may contain information about the communication protocol used by the target access point. Such protocol information can be particularly useful when the access points 100-1, 100-2, 100-3, 100-4 differ with respect to the wireless access technique utilized. Further, such information may include radio resource mapping of control channels of target access points 100-2, 100-3. Further, such information may indicate wireless access techniques used by target access points 100-2, 100-3. In addition, such information is provided to target access points 100-2, 100-3, for example, in the form of random access preambles to be used by the UE 50, or in terms of cell-specific temporary identifiers (eg C-RNTI). It may contain system information for connecting.

Further, the switch permission message 204 is applied by the UE 50 for selection between the different target access points 100-2, 100-3 indicated in the switch permission message 204, for example in the form of a priority or selection policy. May contain information to be.

The switch permission message 204 may be valid for a given period of time. Such a period can be preset in the UE 50 and the access points 100-1, 100-2, 100-3, 100-4 of the wireless communication network. Further, such a period can be dynamically set for each switch permission message. In the exemplary procedure described, the access point 100-1 may set the period before sending the switch permission message 204 and indicate that period in the switch permission message 204. The UE 50 is then allowed to perform the switch automatically while the period has not yet expired. The expiration of the period can be monitored by providing a corresponding timer in the UE 50. The access point 100-1 may set its period, for example, depending on the current speed of the UE 50. For example, if the UE 50 is moving at high speed, a shorter period may be appropriate. Also, in certain cases, the switch permission message 204 may be valid until a particular event, eg, the reception of a new switch permission message or the opening of a connection between the UE 50 and the wireless communication network. In a given scenario, the switch permission message 204 may take precedence over a previously transmitted switch permission message or may be overridden by a later send switch permission message.

In addition to transmitting the switch permission message 204, as indicated by messages 205 and 206, the access point 100-1 also provides information about the UE 50 to the target access points 100-2, 100-determined in step 203. Provide to 3. Such information may include, for example, the context of the UE 50, such as that provided to maintain a connection between the UE 50 and the wireless communication network. Further, the access point 100-1 can start the transfer of the user plane data addressed to the UE 50 to the target access points 100-2 and 100-3. In this method, the target access points 100-2, 100-3 may be ready to continue providing services to the UE 50 immediately after switching connections. The information provided to the target access points 100-2 and 100-3 may also indicate the validity period of the switching permission message 204. Here, if a lifetime greater than the lifetime applied by the UE 50 is indicated to the target cell, thereby the UE 50 attempts to switch connections at the very end of the lifetime indicated to the UE 50, the target access. It may be useful to ensure that points 100-2 and 100-3 are ready. When the access point 100-1 determines the priority of the target access points 100-2 and 100-3, the access point 100-1 moves to different target access points 100-2 and 100-3 in ascending order of priority. That information can be sent.

Upon receiving the switch permission message 204, the UE 50 may initiate a monitoring procedure for the target access points 100-2, 100-3 indicated in the switch permission message 204. For example, the UE 50 may perform measurements to determine which of the indicated target access points 100-2, 100-3 gives the highest expected radio link quality. After such a determination, the UE 50 may continue to monitor only the target access points 100-2, 100-3 with the highest expected radio link quality. In other scenarios, the UE 50 may continue to monitor all of the indicated target access points 100-2, 100-3. Monitoring uses the information provided in the switch permission message 204, eg, the sequence used for the beacon or pilot signal transmitted by the target access points 100-2, 100-3, and at least one of timing and radio resources. sell.

However, the UE 50 does not perform an immediate switch of connections. Rather, the UE 50 performs connection operation switching only in response to detecting a trigger event, as described in step 207. Such a trigger event may be preset in the UE 50 or may be indicated in the switch permission message 204. For example, the trigger event may correspond to a failure of the radio link between the UE 50 and the current serving access point 100-1. Further, such a trigger event causes the expected radio link quality of one of the target access points 100-2, 100-3 to exceed the radio link quality of the current serving access point 100-1 by a given amount. Can correspond to the measurements performed by the UE 50 shown. Further, in such a trigger event, the radio link quality of the current serving access point 100-1 is below the first threshold value, and the expected radio link quality of one of the target access points 100-2 and 100-3 is set. It may correspond to the measurement performed by the UE 50, which indicates that it exceeds the second threshold.

In response to detecting the trigger event in step 207, the UE 50 starts switching the connection to one of the target access points 100-2 and 100-3 indicated in the switch permission message 204. For this purpose, the UE 50 may make a selection between the indicated target access points 100-2, 100-3, as indicated by step 208. For example, the UE 50 may select target access points 100-2, 100-3 that provide the highest expected radio link quality. In the exemplary procedure described, it is assumed that the UE 50 selects the target access point 100-2. The UE 50 is then connected by setting a new radio link to the target access point 100-2 selected in step 208, which is the new serving access point for the UE 50, as described in step 209. Perform a switch.

FIG. 3 shows an exemplary procedure for switching the connection of the UE 50 from the current serving access point 100-1 to another access point 100-2. The procedure of FIG. 3 is similar to that of FIG. 2 in many aspects. However, in the procedure of FIG. 3, different processes are used to provide information about the UE 50 to the target access points 100-2.

In the procedure of FIG. 3, in step 301, the connection between the UE 50 and the wireless communication network is established. As described, the connection is established by setting up a wireless link between the UE 50 and the access point 100-1. Therefore, the access point 100-1 becomes a serving access point for the UE 50.

In step 302, the access point 100-1 detects the trigger event. The trigger event may correspond, for example, to establishing a connection in step 301. Further, the trigger event may be based on at least one of predetermined measurements and evaluations performed by access point 100-1. For example, access point 100-1 measures and evaluates the quality of the radio link between UE 50 and access point 100-1 in terms of, for example, a channel quality indicator, beacon power level, or achievable bit rate. Can be possible. The trigger event can then correspond to the quality of the radio link below a given threshold value. Further, the access point 100-1 can determine the probability of failure of the radio link between the UE 50 and the access point 100-1. For example, this can be accomplished based on radio coverage hole statistics in the radio coverage area of access point 100-1 and information on the location or movement of the UE 50. Further, the access point 100-1 can measure the speed of the UE 50, for example by evaluating the radio signal transmitted by the UE 50, and the trigger event is the speed of the UE 50 exceeding a given threshold value. Can correspond to. In this case, it may be considered that a UE that is moving at high speed is more likely to request a switch to another access point than a UE that is moving at low speed or is stationary. Further, the access point 100-1 evaluates whether the switch permission message previously sent to the UE 50 is valid or expired, and when the switch permission message previously transmitted is no longer valid, the switch permission message is used. Can trigger the transmission of. This can be accomplished, for example, by providing a timer that is reset when the access point 100-1 sends a new switch permission message to the UE 50 and using the expiration of that timer as a trigger event.

In step 303, the access point 100-1 determines a plurality of target access points that make up a candidate for which the connection between the UE 50 and the wireless communication network can be switched. In the illustrated procedure described, it is assumed that these target access points are access points 100-2 and 100-3. The access point 100-1 may apply various criteria for determining the target access points 100-2 and 100-3. For example, the access point 100-1 may select an access point located in the travel direction of the UE 50, or an access point that provides radio coverage in a known coverage hole of the radio within the coverage area of the access point 100-1.

The access point 100-1 then sends a switching permission message 304 to the UE 50. This can be accomplished via a control channel supported by a radio link between the UE 50 and the access point 100-1. The switching permission message 304 indicates the target access points 100-2 and 100-3 determined in step 303. Further, the switch permission message 304 is the target access point 100-2, which is indicated by the switch permission message 304, without requiring further communication between the UE 50 and the access point 100-1 for the connection that the UE 50 is continuing. Allows automatic switching to one or more of 100-3.

The switch permission message 304 may carry various types of information that can be used by the UE 50 to perform automatic switch switching of connections. For example, the switch permission message 304 may indicate one or more conditions for triggering a switch in the UE 50. Such a condition indicates, for example, that the expected radio link quality of one of the target access points 100-2, 100-3 exceeds the radio link quality of the current serving access point 100-1 by a given amount. , Corresponds to the measurements made by the UE 50. Further, under such a condition, the radio link quality of the current serving access point 100-1 is below the first threshold value, and the expected radio link quality of one of the target access points 100-2 and 100-3 is the second. Can correspond to measurements made by the UE 50 that indicate above the threshold of. As a further example, such conditions may correspond to a failure of the radio link or interruption of connection to the current serving access point 100-1.

Further, the switching permission message 304 may indicate information about each of the indicated target access points 100-2 and 100-3. For example, such information may include the identities of target access points 100-2, 100-3, eg, in terms of indexes. Further, such information may include at least one of the sequence, timing, and radio resources used for the beacon or pilot signal transmitted by the target access points 100-2, 100-3. In addition, it may contain information about the communication protocol used by the target access points 100-2, 100-3. Such protocol information may be particularly useful when the access points 100-1, 100-2, 100-3, 100-4 differ with respect to the wireless access technique utilized. Further, such information may include radio resource mapping of control channels of target access points 100-2, 100-3. Further, such information may indicate wireless access techniques used by target access points 100-2, 100-3. In addition, such information is provided to target access points 100-2, 100-3, for example, in the form of random access preambles to be used by the UE 50, or in terms of cell-specific temporary identifiers (eg C-RNTI). It may contain system information for connecting.

Further, the switch permission message 304 is applied by the UE 50 for selection between the different target access points 100-2, 100-3 indicated in the switch permission message 304, for example in the form of a priority or selection policy. May contain information to be.

The switch permission message 304 may be valid for a given period of time. Such a period may be preset in the access points 100-1, 100-2, 100-3, 100-4, 100-5 of the UE 50 and the wireless communication network. Further, such a period can be dynamically set for each switch permission message. In the exemplary procedure described, the access point 100-1 may set the period before sending the switch permission message 304 and indicate that period in the switch permission message 304. The UE 50 is then allowed to perform the switch automatically while the period has not yet expired. The expiration of the period can be monitored by providing a corresponding timer in the UE 50. The access point 100-1 may set its period, for example, depending on the current speed of the UE 50. For example, if the UE 50 is moving at high speed, a shorter period may be appropriate. Also, in certain cases, the switch permission message 304 may be valid until a particular event, eg, reception of a new switch permission message or opening of a connection between the UE 50 and the wireless communication network. In a given scenario, the switch permission message 304 may take precedence over a previously transmitted switch permission message or may be overridden by a later send switch permission message.

Upon receiving the switch permission message 304, the UE 50 may start the monitoring procedure for the target access points 100-2 and 100-3 indicated in the switch permission message 304. For example, the UE 50 may perform measurements to determine which of the indicated target access points 100-2, 100-3 gives the highest expected radio link quality. After such a determination, the UE 50 may continue to monitor only the target access points 100-2, 100-3 with the highest expected radio link quality. In other scenarios, the UE 50 may continue to monitor all of the indicated target access points 100-2, 100-3. Monitoring uses the information provided in the switch permission message 304, eg, the sequence used for the beacon or pilot signal transmitted by the target access points 100-2, 100-3, and at least one of timing and radio resources. sell.

However, the UE 50 does not perform an immediate switch of connections. Rather, the UE 50 performs connection operation switching only in response to detecting a trigger event, as described in step 305. Such a trigger event may be preset in the UE 50 or may be indicated in the switch permission message 304. For example, the trigger event may correspond to a failure of the radio link between the UE 50 and the current serving access point 100-1. Further, such a trigger event causes the expected radio link quality of one of the target access points 100-2, 100-3 to exceed the radio link quality of the current serving access point 100-1 by a given amount. Can correspond to the measurements performed by the UE 50 shown. Further, in such a trigger event, the radio link quality of the current serving access point 100-1 is below the first threshold value, and the expected radio link quality of one of the target access points 100-2 and 100-3 is set. It may correspond to the measurement performed by the UE 50, which indicates that it exceeds the second threshold.

In response to detecting the trigger event in step 305, the UE 50 initiates switching of the connection to one of the target access points 100-2, 100-3 indicated in the switch permission message 304. For this purpose, the UE 50 may make a selection between the indicated target access points 100-2, 100-3, as indicated by step 306. For example, the UE 50 may select target access points 100-2, 100-3 that provide the highest expected radio link quality. In the exemplary procedure described, it is assumed that the UE 50 selects the target access point 100-2. Then, as described in step 307, the UE 50 connects by setting a new radio link to the target access point 100-2 selected in step 306, which is the new serving access point for the UE 50. Perform a switch.

When switching connections in step 307, the UE 50 also indicates the identity of the old serving access point to the new serving access point 100-2, for example in terms of indexing. The new serving access point 100-2 may use this identity to send a request 308 for information about the UE 50 to the old serving access point 100-1.

In response to request 308, access point 100-1 provides information about the UE 50 to the new serving access point 100-2, as indicated by message 309. Such information may include, for example, the context of the UE 50, such as that provided to maintain a connection between the UE 50 and the wireless communication network.

The connection switching procedure described above can be used in conjunction with other types of connection switching procedures, such as connection switching procedures in which the UE 50 is instructed to immediately switch to a predetermined target access point by the current serving access point. In such cases, the automatic switching procedure can be used as a backup in case the instructions for immediate switching are not available, for example due to a failure of the radio link between the UE 50 and the current serving access point. Therefore, if the UE 50 first receives a switch permission message and then a command for immediate switch of connection, the UE 50 first attempts to perform an immediate switch, and if this immediate switch fails, the automatic switch procedure. To continue.

FIG. 5 illustrates a method that can be used to carry out the above concept at an access point in a wireless communication network, eg, at one of access points 100-1, 100-2, 100-3, 100-4. A flowchart for explanation is shown. If a processor-based implementation of the access point is used, the steps of the method may be performed by one or more processors of the access point. To this end, the processor may execute the correspondingly configured program code. In addition, at least some of the corresponding features can be built into the hardware in the processor.

At step 410, the access point provides a connection between the UE, eg UE 50, and the wireless communication network. The connection is based on a wireless link between the UE and the access point. In some scenarios, the connection may also be based on additional wireless links between the UE and other access points.

At step 420, the access point detects the trigger event. Various types of trigger events can be used. For example, the access point may send a message depending on the establishment of a connection between the UE and the communication network. Further, the access point may determine the failure probability of the wireless link between the UE and the access point and send a message in response to the failure probability exceeding the threshold. In addition, the access point may measure the quality of the wireless link between the user terminal and the access point and send a message in response to the quality of the wireless link falling below the threshold. In addition, the access point may measure the speed of the UE and send a message in response to the speed exceeding the threshold. In addition, the access point may send a message in response to determining that a further plurality of target access points previously indicated to the user terminal are no longer valid. In the exemplary procedure of FIGS. 2 and 3, this is accomplished by considering the validity period of the switch permission message.

In step 430, the access point determines a plurality of target access points. This determination may be based on, for example, measurements made by the access point.

At step 440, the access point sends a message to the UE. The message indicates the target access point determined in step 430 and allows the UE to automatically switch connections to one or more of the target access points. As mentioned above, this automatic switching does not require additional interaction between the UE and the access point. The switching permission messages 204 and 304 described above are examples of such messages.

The message may further indicate a condition to be evaluated by the UE to trigger a switch to one or more of the target access points. For example, such conditions may be based on measurements performed by the UE, eg, to determine radio link quality. For example, switching can be triggered when the expected radio link quality for one of the target access points exceeds the access point's radio link quality by a given amount. Further, the switch can be triggered when the expected radio link quality for one of the target access points is above the first threshold and the radio link quality of the access point is below the second threshold. In addition, the switch can be triggered if the wireless link between the UE and the access point fails.

For each of the target access points, the message may further indicate information that should be used by the UE to connect to this target access point. For example, it may include radio settings, access parameters, radio resources, cell-specific temporary identifiers to be used by the UE, and so on. In addition, the message may indicate the priority of the target access point.

In addition, the access point may send information about the UE to each of the plurality of target access points. This information can be used by the target access point to prepare for a potential switch of connections. As mentioned above, this information may include, in particular, the context of the UE, as used to maintain an ongoing connection between the UE and the wireless communication network. As an option, the access point may send such information after switching the connection to one or more of the plurality of target access points. In such a case, the access point may receive a request from the target access point to which the connection is switched, respond to the request, and send information about the UE to the target access point.

FIG. 5 shows a flow chart for explaining a method that can be used in a UE, eg, a UE 50, to carry out the above concepts. If a processor-based implementation of the UE is used, the steps of the method can be performed by one or more processors of the UE. To this end, the processor may execute the correspondingly configured program code. In addition, at least some of the corresponding features can be built into the hardware in the processor.

In step 510, a connection to a wireless communication network, eg, a wireless communication network using the arrangement described in connection with FIG. 1, is established. The connection is based on a wireless link between the UE and the access point of the wireless communication network. In some scenarios, the connection may also be based on additional wireless links between the UE and other access points.

At step 520, the UE receives a message from the access point currently providing the connection. The message indicates multiple target access points and allows the UE to automatically switch connections to one or more of the target access points. As mentioned above, this automatic switching does not require additional interaction between the UE and the access point. The switching permission messages 204 and 304 described above are examples of such messages. In some scenarios, the UE may receive a message depending on establishing a connection between the UE and the communication network.

For each of the target access points, the message may further indicate information that should be used by the UE to connect to this target access point. For example, it may include radio settings, access parameters, radio resources, cell-specific temporary identifiers to be used by the UE, and so on. In addition, the message may indicate the priority of the target access point.

At step 530, the UE determines if a trigger event has occurred. If a trigger event occurs, the method continues with steps 540 and 550, as indicated by the branch "Y". If no trigger event has occurred, the method continues with step 560, as indicated by branch "N".

The trigger event can be based on the quality of the radio link between the UE and the target access point indicated in the message, as measured by the UE. Trigger events can be based on the quality of the radio link between the UE and the access point, as measured by the UE. For example, a trigger event may correspond that the expected radio link quality for one of the target access points exceeds the access point's radio link quality by a given amount. In addition, the trigger event can correspond to the expected radio link quality for one of the target access points being above the first threshold and the radio link quality for the seven access points being below the second threshold. In addition, the trigger event can correspond to a failure of the radio link between the UE and the access point or a disruption of the connection. The message in step 520 indicates a condition that should be evaluated by the UE to trigger the switch to the target access point, and the trigger event may be based on that indicated condition.

At step 540, the UE may select one or more target access points from the plurality of target access points indicated in the message of step 520. This can be accomplished based on the information presented in the message of step 520. For example, the message indicates the priority of the target access point, and the UE may select the target access point according to the indicated priority. Alternatively, a more complex selection policy, eg, a selection policy based on measurements performed by the UE, may be applied by the UE or indicated in the message.

At step 550, the UE switches the connection to the target access point selected in step 540. This can be accomplished based on the information presented in the message of step 520. Specifically, the message may contain information that should be used by the UE to connect to this target access point for each of the indicated target access points, and the UE switches based on this indicated information. Can be executed. In some scenarios, after switching to a target access point, the UE may provide information about the access point, eg, the identity of the access point, to this target access point. If this target access point becomes a new serving access point for the UE, this target access point may use this information to obtain information about the UE from the previous serving access point.

In step 560, if no trigger event is detected in step 530, the UE may maintain the current access point to maintain connectivity.

It should be understood that the methods of FIGS. 4 and 5 can be used in combination, for example, in a UE operating according to the method of FIG. 5 and an access point servicing the UE operating according to the method of FIG. ..

FIG. 6 shows an exemplary structure of an access point for a wireless communication network that can be used to implement the above concepts. For example, the illustrated structure can be used to implement the above-mentioned functionality of access point 100-1, which currently provides a connection between the UE 50 and a wireless communication network.

In the illustrated example, the access point includes a wireless interface 610 that can be used to provide a connection between the wireless communication network and the UE. Further, the access point may include a backhaul interface 620 that can be used to communicate with other nodes of the wireless communication network, such as other access points or gateway nodes.

Further, the access point includes one or more processors connected to interfaces 610 and 620 and a memory 660 connected to the processors. Memory 660 may include read-only memory (ROM), such as flash ROM, RAM, such as dynamic RAM (RAM) or static RAM (SRAM), mass storage devices such as hard disk or solid state disk, or the like. .. The memory includes a properly configured program code module to be executed by processor 650 to implement the functions described with respect to the method of FIG. 4, specifically the functions described above for access node 100-1. More specifically, the program code module in memory 660 performs the above-mentioned function of performing measurements to trigger the transmission of a switch permission message or to determine the target access point indicated in the switch permission message. It may include a measurement module 670 for mounting. In addition, the program code module in memory 660 provides a connection between the UE and the wireless communication network, selects target access points or handles communication with such target access points, and switches permission messages. May include a connection management module 680 for implementing the above-mentioned function of transmitting. Furthermore, the memory 660 may include a control module 690 for implementing common control functions such as control of the radio interface, processing of messages, control of data transfer or the like.

It should be understood that the structure shown in FIG. 6 is merely schematic and that the access point may include in fact additional components, such as additional interfaces or additional processors, which are not illustrated for clarity. be. It should also be understood that the memory 660 may include additional types of program code modules not illustrated, such as program code modules for performing known functions of the access point. Also, in some implementations, computer programs are accessed, for example, in the form of physical media that store program code modules to be stored in memory 660, or by making such program code available for download. May be provided to implement the functionality of the point.

FIG. 7 shows an exemplary structure of a UE that can be used to implement the above concepts. For example, the structure described can be used to perform the above-mentioned functions of the UE 50.

In the illustrated example, the UE includes a wireless interface 710 that can be used to establish a connection to a wireless communication network.

Further, the UE includes one or more processors connected to interfaces 710 and 720 and a memory 760 connected to the processor 750. Memory 760 may include ROMs such as flash ROMs, RAMs such as DRAMs or SRAMs, mass storage devices such as hard disks or solid state disks, or the like. The memory 760 includes a properly configured program code module to be executed by the processor 750 to perform the functions described with respect to the method of FIG. 5, specifically the above-mentioned functions of the UE 50. More specifically, the program code module in memory 760 is a measurement module for implementing the above-mentioned function of triggering a switch or performing a measurement for selecting a target access point among multiple candidates. 770 can be included. In addition, the program code module in memory 760 maintains the connection between the UE and the wireless communication network, selects the target access point, and performs the above-mentioned function of switching the connection as permitted by the switch permission message. May include a connection management module 780 for performing the above. Furthermore, the memory 760 may include a control module 790 for performing common control functions such as control of the radio interface, processing of control messages, or the like.

It is understood that the structure as illustrated in FIG. 7 is merely schematic and the UE may in fact include additional components not illustrated for clarity purposes, such as additional interfaces or additional processors. Should be. It should also be understood that memory 760 may include additional types of program code modules not illustrated, such as program code modules for performing known functions of the UE. Also, in some implementations, the computer program is UE, for example, in the form of a physical medium that stores a program code module to be stored in memory 760, or by making such program code available for download. May be provided to implement the functionality of.

As will be appreciated, the above concepts can be used to effectively manage the UE's connection to the wireless communication network. Specifically, by allowing the UE to automatically switch connections from multiple target access points to one or more, the wireless link between the UE and the UE's current serving access point fails. However, it is possible to switch the connection.

It should be understood that the above examples and embodiments are for illustration purposes only and are easily affected by various modifications. For example, the concepts described may be used in connection with various types of wireless communication networks without being limited to the UDN techniques used in the above exemplary implementations. Furthermore, it is understood that the above concepts can be implemented by using correspondingly designed software that should be run by one or more processors of existing equipment, or by using dedicated device hardware. It should be.

Claims (20)

A method of managing the connection between the user terminal (50) and the wireless communication network.
The access point (100-1) of the wireless communication network provides a connection to the user terminal (50).
The access point (100-1) determines a plurality of target access points (100-2, 100-3).
The access point (100-1) includes transmitting a message (204; 304) to the user terminal (50), and the message (204; 304) is the plurality of target access points (100-2). , 100-3), and the user terminal (50) autonomously switches the connection to one or more of the target access points (100-2, 100-3) in order to execute the handover procedure. Allow to trigger
The message (204; 304) is further evaluated by the user terminal (50) to trigger the switch to the one or more of the target access points (100-2, 100-3). Indicates a power trigger event,
A method characterized by that. The message (204; 304) is further evaluated by the user terminal (50) to trigger the switch to the one or more of the target access points (100-2, 100-3). Indicates multiple trigger events that should be
The method according to claim 1, wherein the method is characterized by the above. The message (204; 304) further
For each of the target access points (100-2, 100-3), the information to be used by the user terminal (50) for connection to the target access point (100-2, 100-3) and the target. The method according to any one of claims 1 or 2, wherein at least one of the priorities of the access points (100-2, 100-3) is indicated. Sending the message (204; 304) in response to the access point (100-1) establishing the connection between the user terminal (50) and the wireless communication network.
The access point (100-1) determines the failure probability of the wireless link between the user terminal (50) and the access point (100-1).
Sending the message (204; 304) in response to the failure probability exceeding the threshold value,
The access point (100-1) measures the quality of the wireless link between the user terminal (50) and the access point (100-1).
Sending the message (204; 304) in response to the quality of the wireless link falling below the threshold.
The access point (100-1) measures the speed of the user terminal (50), and the access point (100-1) measures the speed of the user terminal (50).
Sending the message (204; 304) in response to the speed exceeding the threshold,
The message (204; 304) is transmitted in response to the access point (100-1) determining that the further plurality of target access points previously indicated on the user terminal (50) are no longer valid. That and
The method according to any one of claims 1 to 3, wherein the method comprises at least one of the above. The access point (100-1) has the potential to connect to the target access point (100-2, 100-3) with respect to each of the plurality of target access points (100-2, 100-3). Including transmitting information related to the user terminal (50) to prepare for switching.
The method according to any one of claims 1 to 4, wherein the method is characterized by the above. After switching to one or more (100-2) of the plurality of target access points in the connection, the access point (100-1) makes a request (308) from the target access point (100-2). To receive and
In response to the request (308), the access point comprises transmitting information about the user terminal (50) to the target access point (100-2).
The method according to any one of claims 1 to 5, wherein the method is characterized by the above. A method of managing the connection between the user terminal (50) and the wireless communication network.
The user terminal (50) includes receiving a message (204; 304) from the access point (100-1) of the wireless communication network, wherein the access point (100-1) is the user terminal (50-1). ) Is currently provided, the message (204; 304) indicates a plurality of target access points (100-2, 100-3), and the user terminal (50) indicates a plurality of target access points (100-2, 100-3). It allows autonomous triggering the switching of the connection to one or more of the indicated target access points (100-2, 100-3).
When the user terminal (50) detects a trigger event,
In response to detecting the trigger event, the user terminal (50) switches the connection to one or more of the target access points (100-2, 100-3) in order to execute the handover procedure. That and
Including
The message (204; 304) is further evaluated by the user terminal (50) to trigger the switch to the one or more of the target access points (100-2, 100-3). A method characterized by indicating a power trigger event . The trigger event is a wireless link between the user terminal (50) and the one or more of the target access points (100-2, 100-3) as measured by the user terminal (50). Based on quality,
The method according to claim 7, wherein the method is characterized by the above. The trigger event is based on the quality of the wireless link between the user terminal (50) and the access point (100-1) as measured by the user terminal (50).
The method according to claim 7 or 8, wherein the method is characterized by the above. The trigger event includes the interruption of the connection.
The method according to any one of claims 7 to 9, wherein the method is characterized by the above. The message (204; 304) is further evaluated by the user terminal (50) to trigger the switch to the one or more of the target access points (100-2, 100-3). The method according to any one of claims 7 to 10, wherein a plurality of trigger events are shown . The message (204; 304) further describes, for each of the indicated target access points (100-2, 100-3), to connect to the target access point (100-2, 100-3). Indicates information to be used by the user terminal (50),
The user terminal (50) performs the switch to one or more of the target access points (100-2, 100-3) based on the indicated information.
The message further indicates the priority of the target access points (100-2, 100-3).
The user terminal (50) determines one or more of the target access points (100-2, 100-3) according to the indicated priorities.
The method according to any one of claims 7 to 11, characterized in that. The user terminal (50) comprises receiving the message (204; 304) in response to establishing the connection between the user terminal (50) and the wireless communication network.
The method according to any one of claims 7 to 12, characterized in that. After switching to one or more of the target access points (100-2), the user terminal (50) indicates information about the access point to the target access point (100-2). ,
The method according to any one of claims 7 to 13, characterized in that. An access point (100-1; 100-2; 100-3) for a wireless communication network.
A wireless interface (610) for providing a connection to a user terminal (50), and
The at least one processor (650) includes at least one processor (650).
Determine multiple target access points (100-2, 100-3) and
The message (204; 304) is configured to send a message (204; 304) to the user terminal (50), wherein the message (204; 304) indicates the plurality of target access points (100-2, 100-3) and the user. Allowing the terminal (50) to autonomously trigger the switch of the connection to one or more of the target access points (100-2, 100-3) in order to perform the handover procedure.
The message (204; 304) is further evaluated by the user terminal (50) to trigger the switch to the one or more of the target access points (100-2, 100-3). Indicates a power trigger event,
An access point that features that. The at least one processor (650) is configured to perform the steps of the method according to any one of claims 1-11.
The access point according to claim 15. It is a user terminal (50)
A wireless interface (710) for establishing a connection to a wireless communication network, and
The at least one processor (750) includes at least one processor (750).
-A message (204; 304) is received from the access point (100-1) of the wireless communication network, where the access point (100-1) connects the user terminal (50) to the wireless communication network. The connection is currently being provided, the message (204; 304) indicates a plurality of target access points (100-2, 100-3) and the user terminal (50) is indicated by the target access point (100). -2, 100-3) is allowed to autonomously trigger the switching of the connection to one or more of them.
-Detects trigger events and
-Switching the connection to one or more of the target access points (100-2, 100-3) to perform the handover procedure in response to detecting the trigger event.
Is configured as
The message (204; 304) is further evaluated by the user terminal (50) to trigger the switch to the one or more of the target access points (100-2, 100-3). Indicates a power trigger event,
A user terminal characterized by that. The at least one processor (750) is configured to perform the steps of the method according to any one of claims 7-14.
The user terminal according to claim 17. A computer program comprising program code to be executed by at least one processor (650) of an access point (100-1, 100-2, 100-3) of a wireless communication network, wherein the execution of the program code is. A computer program comprising the at least one processor (650) performing the steps of the method according to any one of claims 1-6. A computer program comprising program code to be executed by at least one processor (750) of the user terminal (50), wherein the execution of the program code is carried out by the at least one processor (750) from claims 7 to 14. A computer program comprising performing the steps of the method according to any one of the above.

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