JP6959189B2 - Mobile communication network user equipment and programs - Google Patents

Description

The present invention relates to a technique for managing the position (mobility) of a user device in a mobile communication network.

In order to improve the communication speed with the user device (UE), it is considered to use so-called millimeter waves such as 28 GHz and 38 GHz in the wireless section of the mobile communication network. The communication distance of millimeter-wave communication is much shorter than the conventional communication distance when a lower radio frequency, specifically, a radio frequency of 2 GHz or less is used. Therefore, the cell size provided by a base station communicating with millimeter waves is, for example, several meters to several tens of meters in radius, which is much larger than the cell size provided by a base station communicating with a conventional lower radio frequency. It becomes smaller. Hereinafter, a base station that communicates at a lower radio frequency such as 2 GHz or less is referred to as a first base station, and a base station that communicates at a higher radio frequency such as millimeter waves is referred to as a second base station. Further, the cell provided by the first base station is referred to as a first cell, and the cell provided by the second base station is referred to as a second cell.

The current mobile communication network provides an uninterrupted service to a user by arranging a plurality of first cells in succession or overlapping a part thereof. On the other hand, in order to arrange the second cell having a very small size continuously like the first cell, it is necessary to install a large number of second base stations, which is not realistic. Therefore, as in the conventional case, it is considered to arrange the first cell continuously or partially overlapping the first cell, and then arrange a plurality of second cells discretely in the first cell. And referred to as a heterogeneous network (HetNet).

On the other hand, for example, a mobile communication network composed of only the first cell performs UE mobility management described below. First, a plurality of adjacent cells are grouped as a tracking area (TA), and the same TA identifier (TAI) is assigned to the first base station belonging to the same TA. Each first base station periodically broadcasts the TAI assigned to its own device. The UE monitors the TAI broadcast by the first base station of the cell in the service area to determine in which TA the own device is in the service area. Then, when the UE enters a different TA or the time spent in the same TA exceeds the threshold value, the UE enters the mobility management device (hereinafter, simply referred to as a management device) of the mobile communication network. The TAI of the TA in the service area is reported via the first base station of the cell. This report is called TA Update (TAU). As a result, the mobile communication network recognizes the position of the UE in units of TA. Then, when the data addressed to the UE arrives at the mobile communication network, the mobile communication network pages the UE via all the first base stations of the TA in which the UE is located. The UE that detects the paging addressed to the own device transmits a response to the paging via the first base station of the cell in which the own device is located. As a result, the mobile communication network recognizes the cell in which the UE is located. After that, the mobile communication network sets a connection with the UE via the first base station of the cell in which the UE is located, and transmits data to the UE via the set connection.

In HetNet, a large number of second cells are arranged, but as described above, the second cell is very small, and a moving UE can pass through the second cell in a very short time. Therefore, when a large number of second cells are arranged, the frequency of TAU by the UE increases, and the power consumption of the UE increases due to the large number of TAUs. Further, in the mobile communication network, the traffic by the TAU, that is, the control traffic increases, and affects the normal traffic, that is, the traffic for data transmission by the user.

Therefore, Non-Patent Document 1 discloses a configuration that reduces the frequency of TAU. Specifically, the UE does not perform TAU immediately after entering the second cell, but performs TAU only when it is still in the second cell even after a predetermined period has elapsed. As a result, TAU is not performed in a situation where the second cell is passed within the predetermined period, and the frequency of TAU can be reduced.

H. L. Fu, et al. , "Reducing Signaling Overhead for Small-cell / Macro-cell Networks", in IEEE Transitions on Mobile Computing, vol. 12, no. 8, pp. 1587-1597, August 2013

In the configuration of Non-Patent Document 1, if the predetermined period is too small than the average time spent in the second cell of the UE, the frequency of TAU does not decrease so much. On the other hand, if the predetermined period becomes too large than the average time spent in the second cell of the UE, the frequency of TAU with respect to the second cell by the UE is greatly reduced. In this case, in the mobile communication network, the UE is the second cell. Even if it is in the cell, it cannot recognize it. Therefore, even if the UE is in the second cell, the UE is paged through the first cell, and the first base station in the first cell is used. Data will be transmitted to the UE via. That is, even if the UE is in the second cell, the frequency of enjoying the advantage of high-speed communication by millimeter waves via the second base station of the second cell is greatly reduced.

The present invention does not increase the frequency of TAU by the UE, and when the data arrives at the UE, the UE is in the cell where high-speed communication is performed, but the UE is located in the cell, but via the base station of the cell. It provides a technology that can reduce the possibility that data cannot be received.

According to one aspect of the present invention, mobile communication having one or more first cells and one or more second cells arranged in at least one first cell of the one or more first cells. When the user device of the network enters one of the entry cells of the one or more second cells, the user device of the network determines whether or not to notify the mobile communication network of the entry into the entry cell, and a determination means. When the determination means determines that the approach is notified to the mobile communication network, the determination means includes a notification means for notifying the mobile communication network of the approach and a frequency determination means for determining the paged frequency, and the frequency is high. The more likely the determination means is to notify the mobile communication network of the approach, the higher the probability .

According to the present invention, if the frequency of TAU by the UE is not increased and the UE is in the cell where high-speed communication is performed when the data arrives at the UE, the UE is located in the cell where high-speed communication is performed, via the base station of the cell. The possibility of receiving data can be increased.

The figure which shows the arrangement of the cell by one Embodiment, and the movement path of a user apparatus. The figure which shows the area information which a management device manages. The figure which shows the area information which a management device manages. The figure which shows the area information which a management device manages. The figure which shows the area information which a management device manages. The figure which shows the area information which a management device manages. The figure which shows the area information which a management device manages. The block diagram of the user apparatus according to one Embodiment. The block diagram of the management apparatus by one Embodiment.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. The following embodiments are examples, and the present invention is not limited to the contents of the embodiments. Further, in each of the following figures, components that are not necessary for the description of the embodiment will be omitted from the drawings.

FIG. 1 shows an exemplary HetNet for explaining this embodiment. Cell 1 is a first cell, in which cells 21 to 26, which are one or more second cells, are arranged. As described above, the second cell is much smaller in size than the first cell, but can communicate with the UE at a higher speed than the first cell. Although FIG. 1 shows only one cell 1 as the first cell, the mobile communication network has one or more first cells, and more generally a plurality of first cells. The plurality of first cells are arranged so as to be continuously, more specifically, partially overlapped at the boundary over the service provision range of the mobile communication network. Then, one or more second cells are arranged in at least one first cell among the one or more first cells.

As described above, the first base station exists in the first cell and the second base station exists in the second cell, but they are omitted for the sake of simplification of the figure. In addition, the mobile communication network has a management device that manages the mobility of the UE. When performing TAU, each UE transmits a TAU message via the base station of the cell in the service area. The management device is also omitted in FIG. 1 for the sake of simplification of the figure.

In the present embodiment, TAI is assigned to the first cell as in the conventional case. In FIG. 1, cell 1 is assigned # 1 as TAI.

In this embodiment, one or more cells 21 to 26 in the same cell 1 are grouped. In FIG. 1, cells 21 to 23 are one group, and cells 24 to 26 are one group. Then, the second cell belonging to the same group is regarded as one TA, and the same TAI is assigned. In FIG. 1, cells 21 to 23 are assigned # 21 as TAI, and cells 24 to 26 are assigned # 22 as TAI.

FIG. 1 also shows the movement path 5 of the UE. The UE enters cell 1 at position 31 and then enters cell 21 at position 32. The UE exits cell 21 at position 33 and enters cell 23 at position 34. Further, the UE exits cell 23 at position 35, enters cell 25 at position 36, and finally exits cell 25 at position 37.

In the present embodiment, the management device includes information on the UE's service area to the TA composed of the first cell (hereinafter, the first TA) and the UE to the TA composed of the second cell (hereinafter, the second TA). Manage area information individually. Here, the operation regarding the TAU of the UE with respect to the first TA is the same as in the conventional case. That is, when the UE enters a different first TA from a certain first TA, it performs a TAU. Further, when the UE continues to stay in the same first TA for the first predetermined period, the UE performs TAU. The operation of the UE with respect to the second TA will be described below.

First, even if the UE exits the second TA and is not in the service area of any second TA, the UE does not notify the management device to that effect. Further, when the UE enters a second TA different from the second TA at the time of the previous TAU, the UE probabilistically performs the TAU. That is, in the present embodiment, when the UE enters a second TA different from the second TA notified to the management device in the previous TAU, the UE may or may not perform the TAU. Further, when the TAU of the second TA is performed, the UE determines whether or not the user is still in the same second TA when the second predetermined period elapses from the timing of performing the TAU, and the UE is in the same second TA. If you do, TAU will be performed. On the other hand, when the second predetermined period elapses from the timing when the TAU of the second TA is performed, the UE does not perform the TAU unless the user is in the service area of any of the second TAs. As described above, in the present embodiment, the UE does not notify the management device that it has become out of service in any of the second TAs, but by not performing the TAU after the lapse of the second predetermined period, eventually The management device is notified after the fact and implicitly that it is not in the second TA of the above.

In addition, when the second TA enters the second TA from a state where it is not in any of the second TAs after the second predetermined period or more has passed from the TAU for the previous second TA, the entered second TA becomes the second TA that performed the previous TAU. Even if they are the same, the UE probabilistically performs TAU when entering the second TA. In other words, the UE manages how the management device manages the state of the UE in the second TA by comparing the timing of performing the TAU indicating the area of the second TA with the second predetermined period. Can be determined. Then, when the UE enters the second TA, if the management device recognizes that the UE is not in the second TA, the UE probabilistically performs the TAU. On the other hand, when the UE enters the second TA, if the management device recognizes that the UE is in the second TA, the UE does not perform the TAU.

Hereinafter, the operation of the UE when the UE moves along the movement path 5 and the service area information managed by the management device will be described with reference to FIGS. 2 to 7. Unless otherwise specified, the travel time from position 32 to position 37 shall be shorter than the second predetermined period. Since cell 21 and cell 23 belong to the same second TA, when the UE performs TAU at position 32, the UE does not perform TAU at position 34. On the other hand, if the UE does not perform TAU at position 32, the UE stochastically performs TAU at position 34. Since the cell 25 belongs to the second TA different from the cells 21 and 23, the UE probabilistically performs the TAU at the position 36 regardless of whether or not the UE performs the TAU at the positions 32 and 34. ..

If the UE is in the first TA different from the cell 1 before the position 31, the UE performs a TAU indicating TAI # 1 at the position 31. On the other hand, if the UE is in the same first TA as the cell 1 before the position 31, the UE does not perform the TAU indicating the cell 1 at the position 31. However, in any case, as shown in FIGS. 2 to 7, the management device manages that the UE is only in the first TA of TAI # 1 while the UE is in the section from the position 31 to the position 32. do.

FIG. 2 shows the service area information in the management device when TAU is performed at both the position 32 and the position 36. The UE performs a TAU indicating TAI # 21 at position 32. As described above, even if the UE exits the cell 21 and is not in the service area of any of the second cells, the UE does not notify the management device to that effect. Further, as described above, since the TAU was performed at the position 32, the TAU is not performed at the position 34. Therefore, the management device manages that the UE is in the first TA of TAI # 1 and the second TA of TAI # 21 while the UE is in the section from the position 32 to the position 36. The UE then performs a TAU indicating TAI # 22 at position 36. Therefore, the management device manages that the UE is in the first TA of TAI # 1 and the second TA of TAI # 22 while the UE is in the section from the position 36 to the position 37.

For example, if the UE is in the cell 21 or the cell 23 at the timing when the second predetermined period elapses after the UE performs the TAU at the position 32, the UE performs the TAU. On the other hand, if the UE is between the position 33 and the position 34 at the timing when the second predetermined period elapses after the UE performs the TAU at the position 32, the UE does not perform the TAU. As a result, the management device updates the service area information of the second TA when the UE is not in the service area of any of the second TAs. In this case, the UE probabilistically performs TAU at position 34.

FIG. 3 shows the service area information in the management device when the TAU is performed at the position 32 but the TAU is not performed at the position 36. The section from position 31 to position 36 is the same as in FIG. However, since the UE did not perform TAU at position 36, the management device said that the UE was in the first TA of TAI # 1 and the second TA of TAI # 21 while the UE was in the section from position 36 to position 37. Manage as it is.

For example, if the UE is in the cell 25 at the timing when the second predetermined period elapses after the UE performs the TAU at the position 32, the management device sets the UE to any second TA at that timing. Recognizes that he is not in the service area.

FIG. 4 shows the service area information in the management device when the TAU is not performed at the position 32 but is performed at the positions 34 and 36. Since the UE did not perform TAU at position 32, the management device manages that the UE is only in the first TA of TAI # 1 while the UE is in the section from position 32 to position 34. After that, since the UE performed the TAU at the position 34, the management device kept the UE in the first TA of the TAI # 1 and the second TA of the TAI # 21 while the UE was in the section from the position 34 to the position 36. Manage when you are there.

FIG. 5 shows the service area information in the management device when the TAU is not performed at the position 32 and the position 36, but the TAU is performed at the position 36. Since the UE did not perform TAU at positions 32 and 34, the management device manages that the UE is only in the first TA of TAI # 1 while the UE is in the section from position 32 to position 36. ..

FIG. 6 shows the service area information in the management device when the TAU is not performed at the positions 32 and 36 but is performed at the position 34. Since the UE did not perform TAU at position 32, the management device manages that the UE is only in the first TA of TAI # 1 while the UE is in the section from position 32 to position 34. After that, since the UE performed the TAU at the position 34, the management device kept the UE in the first TA of the TAI # 1 and the second TA of the TAI # 21 while the UE was in the section from the position 34 to the position 36. Manage when you are there. Further, since the UE did not perform TAU at position 36, the management device was in the management device while the UE was in the first TA of TAI # 1 and the second TA of TAI # 21 while the UE was in the section from position 36 to position 37. Manage as it is.

FIG. 7 shows the service area information in the management device when the TAU is not performed at the positions 32, 34 and 36. Since the UE did not perform the second TA TAU at all positions, the management device states that the UE is only in the first TA of TAI # 1 while the UE is in the section from position 32 to position 37. to manage.

When the data addressed to the UE arrives, the management device determines the service area status of the UE to the second TA based on the service area information of the second TA. That is, the management device determines whether or not the UE is in the second TA, and if it is in the second TA, which second TA is in the service area. When the UE is in the second TA, the mobile communication network pages the UE via all the second base stations of the second TA in the UE. Then, when there is a response from the UE to the paging, the mobile communication network establishes a connection with the UE and transmits data as in the conventional case. On the other hand, if there is no response to paging via the second base station, the mobile communication network will paging through all the first base stations of the first TA in which the UE is located. Since the TAU for the first TA is the same as before, the mobile communication network basically receives the paging response from the UE, and thus establishes a connection with the UE and transmits data as before. can. The process for the case where there is no response to paging via the first base station is the same as in the conventional case. That is, the mobile communication network pages through the first base station of the other first TA around the first TA determined that the management device is in the service area.

As shown in FIGS. 2 to 7, even when the UE is in the second TA, the management device determines that the UE is not in any of the second TAs, or the UE is actually in the service area. There may be a case where the management device determines that the user is in a second TA different from the second TA. At this time, even if the data destined for the UE arrives at the mobile communication network, the mobile communication network pages the UE via the first base station, and thus transmits the data to the UE via the first base station. Will end up. Therefore, if there is a high possibility that data destined for the UE will arrive at the mobile communication network while the UE is in the second cell, TAU is performed to control the area in the second cell. By notifying the UE, there is a high possibility that the UE can receive data at high speed via the second base station. On the other hand, if it is unlikely that the data destined for the UE will arrive at the mobile communication network while the UE is in the second cell, the frequency of the TAU can be reduced by not performing the TAU. Can be done. Therefore, in the present embodiment, when the UE enters the second cell, it generates a determination value indicating the possibility that data addressed to the UE may arrive at the mobile communication network while in the second cell. Then, it is determined whether or not to perform TAU based on the determination value. Hereinafter, a specific description will be given.

FIG. 8 is a configuration diagram of a UE according to the present embodiment. The arrival frequency determination unit 41 calculates the frequency (hereinafter referred to as “arrival frequency”) in which data addressed to the own device arrives at the mobile communication network and paging is received from the mobile communication network. For example, if you have received 50 pagings in the last 10 hours, the arrival frequency is 5 times / hour. The period used for the calculation can be a predetermined period in the past. Alternatively, the entire period from the time when the power was turned on last time can be used for the calculation. Furthermore, the entire period after the power is turned on for the first time can be used for the calculation. Furthermore, the period from the predetermined timing such as midnight on January 1st of each year, midnight on the first day of every month, and midnight of every Sunday to the present can be used for calculation. can. Hereinafter, the arrival frequency determined by the arrival frequency determination unit 41 is defined as λ.

Further, the arrival frequency determination unit 41 measures the elapsed time E from the previous paging received from the mobile communication network.

The staying time determination unit 42 calculates the average value of the staying time in the second cell of the own device (hereinafter referred to as the staying average value). For example, if the UE stays in the three cells for 1 minute, 5 minutes, and 6 minutes, respectively, the average stay value is 4 minutes. The same concept as the arrival frequency can be applied to the period used for the calculation. Alternatively, it can be the average value of the time spent in the second cell of a predetermined number in the past. Hereinafter, the average stay value determined by the stay time determination unit 42 is defined as S.

The TAU execution determination unit 43 acquires the arrival frequency λ and the elapsed time E from the arrival frequency determination unit 41 in order to determine whether or not to perform the TAU when entering the second cell, and the stay time determination unit 42 obtains the arrival frequency λ and the elapsed time E. Acquire the average stay value S. The TAU execution determination unit 43 sets x = S + E and obtains the determination value P by the following equation (1).
P = 1-e ^−λx (1)
Then, the TAU execution determination unit 43 generates a random number R of 0 or more and 1 or less, determines that TAU is executed when the random number R is equal to or less than the determination value P, and executes TAU when the random number R is larger than the determination value P. Do not decide.

Therefore, the larger the determination value P, the higher the probability that TAU will be performed. Here, as is clear from the equation (1), the determination value P becomes larger as the arrival frequency λ is higher, the stay average value S is longer, and the elapsed time E from the previous paging is longer. The higher the arrival frequency λ, the longer the average stay value S, and the longer the elapsed time E from the previous paging, the higher the probability of paging from the mobile communication network while the UE is in the second cell. Become. Therefore, the higher the arrival frequency λ, the longer the average stay value S, and the longer the elapsed time E from the previous paging, the higher the probability that TAU will be performed, so that the UE is in the second TA. Nevertheless, the state of receiving data via the first base station can be reduced.

On the other hand, if the arrival frequency λ is low, the average stay value S is short, and the elapsed time E from the previous paging is short, the probability that the UE will be paging while the UE is in the second TA is also low. In such a case, even if the UE performs TAU, there is a high possibility that it will be useless TAU. Therefore, in such a case, by not performing TAU, unnecessary TAU can be suppressed, and thus an increase in UE power consumption and an increase in control traffic to the mobile communication network can be suppressed. The communication unit 43 is a wireless interface for transmitting and receiving TAU messages and the like to and from the base station. The determination value P may be determined based on at least one of the arrival frequency λ, the average stay value S, and the elapsed time E from the previous paging.

FIG. 9 is a configuration diagram of the management device according to the present embodiment. The management unit 61 manages the territorial information of the UE as described with reference to FIGS. 2 to 7 based on the TAU of the first TA and the TAU of the second TA received from the UE. When the data to the UE arrives at the mobile communication network and the UE needs to be paging, the determination unit 62 determines the sphere status of the UE managed by the management unit 61 to the first TA and the second TA. do. The paging processing unit 63 performs paging processing to the UE based on the determination result by the determination unit 62. The communication unit 64 performs communication processing with various nodes including a base station of a mobile communication network.

As described above, the determination unit 62 first determines the state of being in the second TA, and if it is not in the second TA, the determination unit 62 determines the state of being in the first TA. Further, even if there is no response from the UE even if the paging processing unit 63 paging the UE via the second base station based on the determination result of the determination unit 62, the occupancy state to the first TA is determined.

41: Arrival frequency determination unit, 42: Stay time determination unit, 43: TAU execution determination unit, 44: Communication unit

Claims (9)

A user device of a mobile communication network having one or more first cells and one or more second cells arranged in at least one first cell of the one or more first cells.
When entering one of the entry cells of the one or more second cells, a determination means for determining whether or not to notify the mobile communication network of the entry into the entry cell, and a determination means.
When the determination means determines that the approach is notified to the mobile communication network, the notification means for notifying the mobile communication network of the approach and the notification means.
A frequency determination means for determining the frequency of paging, and
Equipped with a,
The user device is characterized in that the higher the frequency, the higher the probability that the determination means notifies the mobile communication network of the approach. A user device of a mobile communication network having one or more first cells and one or more second cells arranged in at least one first cell of the one or more first cells.
When entering one of the entry cells of the one or more second cells, a determination means for determining whether or not to notify the mobile communication network of the entry into the entry cell, and a determination means.
When the determination means determines that the approach is notified to the mobile communication network, the notification means for notifying the mobile communication network of the approach and the notification means.
A staying time determining means for determining the staying time in one or more of the second cells, and
With
The stay longer the average value of time, the determination means the approach said moving feature and be Ruyu over The device that the probability of notifying increases the communication network. A user device of a mobile communication network having one or more first cells and one or more second cells arranged in at least one first cell of the one or more first cells.
When entering one of the entry cells of the one or more second cells, a determination means for determining whether or not to notify the mobile communication network of the entry into the entry cell, and a determination means.
When the determination means determines that the approach is notified to the mobile communication network, the notification means for notifying the mobile communication network of the approach and the notification means.
Elapsed time determination means for determining the elapsed time since the previous paging , and
With
The elapsed time is longer, the determination means, wherein the to Ruyu over The device that the probability of notifying the ingress to the mobile communication network is high. A user device of a mobile communication network having one or more first cells and one or more second cells arranged in at least one first cell of the one or more first cells.
Whether or not to generate a determination value when entering one of the entry cells of the one or more second cells and notify the mobile communication network of the entry to the entry cell based on the generated determination value. Judgment means for determining
When the determination means determines that the approach is notified to the mobile communication network, the notification means for notifying the mobile communication network of the approach and the notification means.
With
The determination value is a value based on the frequency at which the user device is paging, the time spent in the one or more second cells of the user device, and the elapsed time from the previous paging to the user device. features and to Ruyu over laser device that is obtained based on one or more. The higher the frequency, the higher the probability that the determination means notifies the mobile communication network of the approach.
The longer the average value of the staying time, the higher the probability that the determining means notifies the mobile communication network of the approach.
The user device according to claim 4, wherein the longer the elapsed time, the higher the probability that the determination means notifies the mobile communication network of the approach. A user device of a mobile communication network having one or more first cells and one or more second cells arranged in at least one first cell of the one or more first cells.
When entering one of the entry cells of the one or more second cells, a determination means for determining whether or not to notify the mobile communication network of the entry into the entry cell, and a determination means.
When the determination means determines that the approach is notified to the mobile communication network, the notification means for notifying the mobile communication network of the approach and the notification means.
With
The one or more second cells are grouped and
When entering the entry cell within a predetermined period after notifying the mobile communication network that the mobile communication network is in the second cell of the same group as the entry cell, the determination means enters the entry cell. the mobile does not inform the communication network, wherein the to Ruyu over laser device to determine. If the notification means has not entered the second cell of a group different from the entry cell by the timing when the predetermined period elapses after notifying the mobile communication network of the approach, the determination means has not entered the second cell of a group different from the entry cell. At the timing, it is determined whether the user is in the second cell of the same group as the entry cell or is not in any of the second cells.
When the determination means determines at the timing that it is in the second cell of the same group as the entry cell, the notification means is in the second cell of the same group as the entry cell. The user device according to claim 6 , wherein the mobile communication network is notified of the fact. Even if the determination means determines that the device is not in any second cell at the timing, the mobile communication network indicates that the notification means is not in any second cell. The user apparatus according to claim 7 , wherein the user device is not notified. A program according to any one of claims 1 to 8, wherein the computer functions as the user device.

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