JP2011166583A - Mobile communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem when a wireless resource cannot be allocated by only one RAN so that QoS required by a mobile terminal is satisfied. <P>SOLUTION: A mobile communication system having a plurality of wireless access network systems is provided with: an integrated wireless environment information database 2 for storing wireless quality information representing wireless quality at a specific position for each wireless access network system; and a wireless resource manager 3 for selecting the wireless access network system suitable for an estimated moving path relating to a specific terminal based on the integrated wireless environment information database 2, and performing wireless resource allocation control so that the wireless resource is allocated cooperatively to the terminal among the selected wireless access network systems. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a mobile communication system.

  For example, Patent Literatures 1 and 2 are known as switching technologies for RANs accessed by terminals in a mobile communication system having a plurality of radio access network systems (RANs). In the prior art of Patent Document 1, switching of communication media is predicted based on reception power characteristics and switching occurrence characteristics in the course of a moving path until the mobile terminal reaches a predicted position, and switching of communication media is performed based on the prediction results. Are preparing. In the prior art of Patent Document 2, a wireless medium having a good communication status is determined based on wireless information acquired by each wireless module.

JP 2007-74292 A JP 2008-167285 A

  However, the above-described conventional technique has a problem to be dealt with when it is not possible to allocate radio resources with only one RAN so as to satisfy QoS (Quality of Service) required by the mobile terminal.

  The present invention has been made in consideration of such circumstances, and a mobile communication system capable of coping with a case where radio resources cannot be allocated with only one RAN so as to satisfy the QoS required by the mobile terminal. It is an issue to provide.

  In order to solve the above-described problems, a mobile communication system according to the present invention is a mobile communication system having a plurality of radio access network systems, wherein radio quality information representing radio quality at a specific position for each radio access network system. And a radio access network system suitable for an expected movement path related to a specific terminal based on the integrated radio environment information database, and the selected radio access network systems cooperate with each other. And a radio resource manager that performs radio resource allocation control so as to allocate radio resources to the terminal.

  In the mobile communication system according to the present invention, the radio resource manager includes an expected stay time calculation unit that calculates an expected time for a specific terminal to stay in the same cell of the radio access network system.

  In the mobile communication system according to the present invention, the radio resource manager includes a radio at a specific time for each radio access network system having a cell including an expected position at a specific time for a specific high-speed terminal having a speed equal to or higher than a specified speed. It has a radio | wireless resource condition estimation part which estimates a resource condition.

  In the mobile communication system according to the present invention, the radio resource status estimation unit determines whether a radio resource requirement for satisfying the required QoS of the high-speed terminal can be allocated in the radio access network system to be estimated. It is characterized by that.

  In the mobile communication system according to the present invention, the radio resource status estimation unit determines whether or not a radio resource utilization rate related to the radio access network system to be estimated is a predetermined value or less.

  In the mobile communication system according to the present invention, the radio resource manager attempts to replace terminals between radio access network systems having a cell including an expected position at the specific time based on the estimation result of the radio resource status. It has a cooperative control part.

  In the mobile communication system according to the present invention, the cooperative control unit is configured to perform the high-speed operation in a radio access network system having a maximum expected stay time of the high-speed terminal in a radio access network system having a cell including an expected position at the specific time. It is characterized by trying to change the accommodation of the terminal so as to secure the required amount of radio resources to satisfy the required QoS of the terminal.

  In the mobile communication system according to the present invention, the cooperative control unit accommodates a radio access network system having a radio resource utilization rate equal to or less than a specified value among radio access network systems having a cell including an expected position at the specific time. As described above, it is characterized by trying to change the accommodation of the terminal.

  In the mobile communication system according to the present invention, the integrated radio environment information database and the radio resource manager are provided on a base station side.

  In the mobile communication system according to the present invention, the integrated radio environment information database and the radio resource manager are also provided in a terminal, and the radio resource manager of the terminal and the radio resource manager of the base station jointly select a radio access network system. It is characterized by that.

  In the mobile communication system according to the present invention, when the radio resource manager on the base station side and the radio resource manager on the terminal jointly perform radio resource management and radio access network system selection, the radio on the base station side It is characterized by being led by a resource manager.

  In the mobile communication system according to the present invention, when the radio resource manager on the base station side and the radio resource manager on the terminal jointly manage radio resources and select a radio access network system, the radio resources on the terminal side It is characterized by being led by a manager.

  In the mobile communication system according to the present invention, when the radio resource manager of the base station side and the radio resource manager of the terminal jointly perform radio resource management and radio access network system selection, the base station side or the The radio resource manager on the base station side determines which radio resource manager of the terminal will take the lead based on the QoS level on the terminal side or the margin of the radio resource utilization rate.

  In the mobile communication system according to the present invention, one set of the integrated radio environment information database and the radio resource manager is provided for one or a plurality of radio access network systems, and radio resources are coordinated for a plurality of radio resource managers. It is characterized by having a centralized coordination unit that performs centralized control.

  According to the present invention, when it is not possible to allocate radio resources with only one RAN so as to satisfy the QoS required by the mobile terminal, it is possible to cope with the problem by coordinating radio resources between the RANs. become able to.

1 is a configuration example of a mobile communication system according to a first embodiment of the present invention. 3 is a configuration example of a mobile communication system according to the embodiment. It is a conceptual diagram which shows the structural example of the integrated radio | wireless environment information database 2 which concerns on this invention. It is a block diagram which shows the structure of the radio | wireless resource manager 3 which concerns on this invention. It is a conceptual diagram for demonstrating the radio | wireless resource allocation control method which concerns on 1st Embodiment of this invention. It is an example which selects the optimal cell which concerns on this invention. It is a sequence diagram which shows the whole procedure of the radio | wireless resource allocation control method which concerns on 1st Embodiment of this invention. It is a flowchart which shows the flow of a process of the radio | wireless resource manager 3 which concerns on 1st Embodiment of this invention. It is an example of the accommodation destination candidate RAN selection method of step S2 of FIG. It is an example of the RAN selection criteria for demonstrating the accommodation destination candidate RAN selection method which concerns on this invention. It is a structural example of the mobile communication system which concerns on 2nd Embodiment of this invention. FIG. 4 is a sequence diagram showing an overall procedure of a radio resource allocation control method according to the same embodiment. 1 is a first embodiment of a base station 10 and a terminal 100 of a mobile communication system according to the present invention. 7 is a second embodiment of the base station 10 and the terminal 100 of the mobile communication system according to the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
1 and 2 are configuration examples of a mobile communication system according to the first embodiment of the present invention. In FIG. 1, the mobile communication system has a plurality of radio access network systems (RAN). In the example of FIG. 1, a RAN having a macro cell base station BS_A that provides a macro cell, a RAN having a micro cell base station BS_B that provides a micro cell, and a RAN having a pico cell base station BS_C that provides a pico cell are shown. Yes. Each cell has an overlapping part, and the terminal can use any of the overlapping cells in the cell overlapping part.

  In the first embodiment, an integrated radio resource manager (IRRM) 1 is provided as a centralized control device related to radio resource allocation. The integrated radio resource manager 1 includes an integrated radio environment information database (IRED) 2 and a radio resource manager (RRM) 3. In the example of FIG. 2, seven macro cells 310 to 370 are the area 300 in charge of the integrated radio resource manager 1. In each of the macro cells 310 to 370, a micro cell or a pico cell may exist. For example, the macro cell 320 includes a micro cell and a pico cell. The integrated radio resource manager 1 can communicate with all the base stations BS_A, B, and C in the assigned area 300 and can send and receive data to and from each base station BS_A, B, and C.

  In FIG. 2, as a terminal of the mobile communication system, a terminal that is not moving or moving at low speed (hereinafter, a terminal that is not moving or moving at low speed is referred to as a low speed terminal for convenience) MS_a And a high-speed terminal MS_b moving at high speed.

  The integrated radio environment information database 2 stores radio quality information representing radio quality for each RAN at a specific position. FIG. 3 is a conceptual diagram illustrating a configuration example of the integrated wireless environment information database 2. In FIG. 3, the integrated wireless environment information database 2 includes map information (two-dimensional map or three-dimensional map), position information of base stations and terminals, and wireless quality information indicating the wireless quality at a specific position of each RAN. Have. The location information of the base station and the terminal is associated with the map information. The integrated wireless environment information database 2 stores each information in time series (for example, together with time information).

  The radio quality information of each RAN is associated with map information. In FIG. 3, LTE (Long Term Evolution), WiMAX, WiFi, femto, and the like are shown as examples of RAN types. Other types of RANs can be used. Also, CQI (Channel Quality Indicator), delay and throughput information are stored as LTE radio quality information, and CINR (Carrier to Interference and Noise power Ratio), delay and throughput information are stored as WiMAX radio quality information, RSSI (Received Signal Strength Indicator), delay, and throughput information are stored as wireless quality information of WiFi and femto.

  The radio resource manager 3 selects a RAN suitable for an expected movement route related to a specific terminal based on the integrated radio environment information database 2, and the selected RAN cooperates with another RAN as necessary to Radio resource allocation control is performed so as to allocate radio resources to terminals. FIG. 4 is a block diagram showing the configuration of the radio resource manager 3. In FIG. 4, the radio resource manager 3 includes an expected stay time calculation unit 31, a radio resource status estimation unit 32, and a cooperative control unit 33.

  The expected stay time calculation unit 31 calculates the expected time for a specific terminal to stay in the same cell of the RAN. The radio resource status estimation unit 32 estimates the radio resource status at a specific time for each RAN including a cell including an expected position at a specific time related to a specific high-speed terminal having a speed equal to or higher than a specified rate. In the estimation of the radio resource status, the radio resource status estimation unit 32 determines whether the radio resource requirement for satisfying the required QoS of the high-speed terminal can be allocated in the estimation target RAN. Further, the radio resource status estimation unit 32 determines whether or not the radio resource utilization rate related to the estimation target RAN is equal to or less than a specified value.

  Based on the estimation result of the radio resource status by the radio resource status estimation unit 32, the cooperative control unit 33 attempts to change the terminal accommodation between RANs having cells including the expected position at a specific time. In this terminal exchange, the cooperative control unit 33 uses the radio resource for satisfying the required QoS of the high-speed terminal in the RAN having the maximum expected stay time of the high-speed terminal among the RANs having the cell including the predicted position at the specific time. In order to secure the required amount, the change of accommodation from the RAN having the maximum expected stay time of the high speed terminal to another RAN (for example, the expected stay time is short) for other terminals other than the high speed terminal Try. In addition, the cooperative control unit 33 sets a RAN having a radio resource utilization rate equal to or less than a specified value among RANs having cells including an expected position at a specific time as an accommodation replacement destination from a RAN having a maximum expected stay time of a high-speed terminal. In order to secure a radio resource requirement for satisfying the required QoS of the high-speed terminal in the RAN in which the expected stay time of the high-speed terminal is the maximum, the terminal is accommodated for other terminals other than the high-speed terminal. Try changing.

  FIG. 5 is a conceptual diagram for explaining the radio resource allocation control method according to the present embodiment. In FIG. 5, the high-speed terminal MS_b_1 is moving along the expected movement route R. The predicted travel route R is acquired based on information (departure point and destination or predicted travel route information) previously reported from the high-speed terminal MS_b_1, and is held by the radio resource manager 3. Alternatively, the information on the expected movement route R may be held in the integrated radio environment information database 2 in response to a request from the radio resource manager 3. Alternatively, means for estimating the expected movement route R from the speed and movement direction of the high-speed terminal MS_b_1 may be provided.

  The current location of the high-speed terminal MS_b_1 is a (xi, yi, zi) point on the predicted travel route R, and the high-speed terminal MS_b_1 is on the predicted travel route R at a specific time (after T time) depending on the travel speed and the traveling direction. The point (xj, yj, zj) is scheduled to be reached. The point (xi, yi, zi) is in the macro cell 310. In this example, the (xj, yj, zj) point is in the macro cell 320 and in the area where the communicable area overlaps with the micro cell and the pico cell. At this time, the radio resource manager 3 selects the optimum cell for the high speed terminal MS_b_1 from the macro cell 320, the micro cell, and the pico cell in which the communicable areas overlap, and uses the radio resource related to the selected cell for the high speed terminal MS_b_1. Radio resource allocation control is performed to ensure that

  FIG. 6 is an example of selecting an optimal cell. In FIG. 6, the macro cell of RAN2 is arranged between the two macrocells of RAN1 on the expected movement route R of the high-speed terminal MS_b. A high communication quality with high throughput and low delay is obtained at a point where the radio wave condition in the vicinity of the base station in the cell of RAN1 is good, but the radio wave condition is poor at the boundary between the two macro cells of RAN1, and the high communication quality is obtained. It is a situation that cannot be obtained. On the other hand, at the boundary portion between the two RAN1 macrocells, the RAN2 macrocell where the service areas overlap has a good radio wave condition, and high communication quality with high throughput and low delay can be obtained. In such a case, the access destination of the high-speed terminal MS_b is once switched from RAN1 to RAN2 at the boundary between the two macro cells of RAN1, and the access destination of the high-speed terminal MS_b is switched again to RAN1 at the cell edge of RAN2. As a result, it is possible to maintain a high-quality wireless environment with high throughput and low delay for the high-speed terminal MS_b and contribute to satisfying the required QoS of the high-speed terminal MS_b.

FIG. 7 is a sequence diagram showing an overall procedure of the radio resource allocation control method according to the present embodiment. Here, it demonstrates concretely using the example of FIG.
In FIG. 7, in step S100i, all the terminals in the RAN service area of the macro cell 310 including the current location (xi, yi, zi) of the high-speed terminal MS_b_1 are integrated wireless information and information such as request QoS. Register in the environment information database 2. In step S200i (S210i, S220i, S230i), in response to a request from a function block (for example, one function block inside the radio resource manager 3) that controls the integrated radio environment information database 2, the current location (xi, Each base station BS (xi, yi, zi) _RAN 1, 2, 3 of RAN 1, 2, 3 accessible by yi, zi) registers the radio resource status (congestion information, location) in the integrated radio environment information database 2 To do.

  In step S100j, all terminals in the RAN service area of the macro cell 320 including the point (xj, yj, zj) register information such as their radio status and request QoS in the integrated radio environment information database 2. In step S200j (S210j, S220j, S230j), the expected position (xj, yj, zj) of the high-speed terminal MS_b_1 at a specific time (after T time) in response to a request from the functional block that controls the integrated wireless environment information database 2 The base stations BS (xj, yj, zj) _RAN 1, 2, 3 of RAN 1, 2, 3 that can be accessed in (1) register the radio resource status (congestion information, location) in the integrated radio environment information database 2.

  In step S300, the radio resource manager 3 classifies information on terminals and base stations within the jurisdiction area stored in the integrated radio environment information database 2, and further calculates the moving speed of the high speed terminal MS_b_1. At this time, when separately calculating or holding the movement information using GPS (Global Positioning System) or the like, the information on the existing movement speed is used without newly calculating the movement speed. The radio resource manager 3 then accesses each base station accessible at the expected position (xj, yj, zj) of the high speed terminal MS_b_1 at a specific time (after T time) based on the movement speed of the high speed terminal MS_b_1 and the expected movement route R. The movement distance in the cell of BS (xj, yj, zj) _RAN1, 2, 3 is calculated. Then, the radio resource manager 3 determines each base station (xj, 1) of the high-speed terminal MS_b_1 based on the moving speed of the high-speed terminal MS_b_1 and the moving distance in the cell of each base station BS (xj, yj, zj) _RAN1,2,3. yj, zj) The estimated stay time in the cells of RAN1, 2, 3 is calculated. Further, the radio resource manager 3 calculates a radio resource requirement for satisfying the requested QoS of the high speed terminal MS_b_1 for each of the RANs 1, 2, and 3. Note that the estimated stay time is self-evident if the travel distance and travel speed in each cell are known, so if the travel speed is roughly the same, do not calculate the expected stay time and instead use the travel distance instead of the expected stay time. You may make it compare.

  In step S330, the radio resource manager 3 determines the radio resource status of each RAN 1, 2, 3 at the expected position (xj, yj, zj) of the high-speed terminal MS_b_1 at a specific time (after T time) and the terminal accommodation status. Then, a guideline for inter-RAN cooperation related to radio resource allocation is determined. In step S500, the radio resource manager 3 requests each base station BS (xj, yj, zj) _RAN1, 2, 3 to perform inter-RAN coordination related to radio resource allocation. At this time, when the RAN optimal for the high-speed terminal MS_b_1 (in this example, RAN1) is congested, the radio resource manager 3 is another terminal accommodated by the RAN1 (for example, a terminal having a low priority). ) To other RAN2 or 3 is tried.

  In step S600 (S610, S620, S630), each base station BS (xj, yj, zj) _RAN1, 2, 3 performs radio resource allocation in response to a request from a functional block that controls the integrated radio environment information database 2. The radio resource status (congestion information, location) as a result of the inter-RAN cooperation is registered in the integrated radio environment information database 2. In step S700, the radio resource manager 3 notifies the high-speed terminal MS_b_1 of the RAN (RAN1 in this example) that can be used at the destination (the expected position (xj, yj, zj) at the specific time (after T time)). To do.

FIG. 8 is a flowchart showing a processing flow of the radio resource manager 3 according to the present embodiment. Here, it demonstrates concretely using the example of FIG.
In FIG. 8, in step S1, the radio resource manager 3 estimates the radio resource status after T time for each RAN having a cell including the expected position (xj, yj, zj) of the high-speed terminal MS_b_1 after T time. .

  As a specific process of step S1, first, information such as the positions and distribution statuses of base stations and terminals is read from the integrated wireless environment information database 2. Next, the terminal movement state (high-speed movement, low-speed movement or not moving state), communication state, requested QoS, and the like are acquired. Next, the predicted position (xj, yj, zj) of the high-speed terminal MS_b_1 after T time is calculated from the current position, the moving speed, and the predicted moving route R of the high-speed terminal MS_b_1. Next, information such as the identifier (ID) of the base station (xj, yj, zj) _RAN1, 2, 3 of the RAN (RAN1, 2, 3) having the cell including the expected position (xj, yj, zj) is acquired. . Next, the area quality of the base stations (xj, yj, zj) _RAN1,2,3 of each RAN1,2,3, the overlapping portion, and the radio resource utilization rate (congestion degree) of each cell are calculated. Next, the request QoS of the high speed terminal MS_b_1 is acquired. Next, for each base station (xj, yj, zj) _RAN1,2,3 of each RAN1,2,3, statistical values of radio quality (reception strength, etc.) on the expected movement path R and expected throughput And the delay are calculated, and the radio resource requirement for satisfying the required QoS of the high speed terminal MS_b_1 is calculated. Next, the low-speed terminal MS_a is extracted from the terminals accommodated in the base stations (xj, yj, zj) _RAN1,2,3 of each RAN1,2,3.

  In step S2, the radio resource manager 3 selects a RAN candidate (accommodating destination candidate RAN) that accommodates the high speed terminal MS_b_1 at the expected position (xj, yj, zj) of the high speed terminal MS_b_1 after T time. Here, it is assumed that RAN1 is selected from RAN1 (macrocell), RAN2 (microcell), and RAN3 (picocell).

In step S3, the radio resource manager 3 determines whether the accommodation destination candidate RAN1 satisfies the requirement condition. The required conditions (1) and (2) are shown below.
(1) It is possible to allocate a radio resource requirement for satisfying the required QoS of the high-speed terminal. Specifically, the conditional expression “RB_Available> RB_REQ (MS_b)” is satisfied. However, RB_Available is the amount of radio resources that can be used by the accommodation destination candidate RAN, and RB_REQ (MS_b) is the radio resource requirement of the high-speed terminal MS_b.
(2) The radio resource utilization rate is below a specified value. Specifically, the conditional expression “Ur (RAN) ≦ Uthr (RAN)” is satisfied. However, Ur (RAN) is a RAN radio resource utilization rate, and Uthr (RAN) is a specified value of the RAN radio resource utilization rate.

  In calculating the radio resource requirement RB_REQ (MS_b) of the high-speed terminal MS_b, the request QoS of the application in communication (for example, in real-time video transmission / reception and voice call, the throughput is 2 Mbps or more and the delay (RTT) is within 150 ms) and It can be estimated by using a statistical value of the reception strength within the moving section of the high-speed terminal MS_b and a relational expression or table of the known reception strength, communication speed, transmission error rate, and RTT.

  In step S4, as a result of the determination in step S3, the radio resource manager 3 proceeds to step S5 if the accommodation destination candidate RAN1 satisfies the requirement condition, and proceeds to step S6 if the requirement condition is satisfied.

  In step S5, since the accommodation destination candidate RAN1 satisfies the requirements, the radio resource manager 3 performs radio resources for the high-speed terminal MS_b_1 after T time with respect to the base station (xj, yj, zj) _RAN1 of the accommodation destination candidate RAN1. Instruct to secure. Thereby, the base station (xj, yj, zj) _RAN1 of the accommodation destination candidate RAN1 performs a process of securing radio resources for the high-speed terminal MS_b_1 after T time.

  On the other hand, in step S6, because the accommodation destination candidate RAN1 does not satisfy the required condition, the radio resource manager 3 can select a candidate for the low speed terminal MS_a (accommodation candidate terminal) MS_a_HO to be accommodated from the accommodation destination candidate RAN1 to another RAN2,3. Select. The accommodation change candidate terminal MS_a_HO is the low speed terminal MS_a accommodated in the RAN1, can use the RAN2 or the RAN3, and has the lower priority. At this time, the radio resource manager 3 selects one or a plurality of accommodation replacement candidate terminals MS_a_HO so as to satisfy the following expression “RB_REQ (HO) ≧ RB_REQ (MS_b)”. However, RB_REQ (HO) is the total radio resource requirement of each accommodation replacement candidate terminal MS_a_HO.

In step S7, the radio resource manager 3 determines the RAN that can accommodate the accommodation replacement candidate terminal MS_a_HO. Here, the RAN that can accommodate the accommodation change candidate terminal MS_a_HO is determined from RAN2 and RAN3. The determination conditions (1) and (2) are shown below.
(1) It is possible to allocate the radio resource requirement of the accommodation change candidate terminal MS_a_HO. Specifically, the conditional expression “RB_Available> RB_REQ (MS_a_HO)” is satisfied. However, RB_Available is the amount of radio resources that can be used in the accommodation change destination candidate RAN, and RB_REQ (MS_a_HO) is the required radio resource amount of the accommodation change candidate terminal MS_a_HO.
(2) The radio resource utilization rate is below a specified value. Specifically, the conditional expression “Ur (RAN) ≦ Uthr (RAN)” is satisfied. However, Ur (RAN) is a RAN radio resource utilization rate, and Uthr (RAN) is a specified value of the RAN radio resource utilization rate.

  In step S7, if the result of determination in step S7 is that there is a RAN that satisfies the determination condition and the accommodation replacement candidate terminal MS_a_HO can be accommodated, the radio resource manager 3 proceeds to step S9. On the other hand, as a result of the determination in step S7, when there is no RAN that satisfies the determination condition and the accommodation change candidate terminal MS_a_HO cannot be changed, the process of FIG.

  In step S9, the radio resource manager 3 instructs the accommodation destination candidate RAN1 and the accommodation change destination candidate RAN to change the accommodation change candidate terminal MS_a_HO from the accommodation destination candidate RAN1 to the accommodation change destination candidate RAN. Thereafter, the process returns to step S3.

  FIG. 9 is an example of the accommodation destination candidate RAN selection method in step S2 of FIG. In FIG. 9, in step S21, the radio resource manager 3 performs, for each RAN (RAN 1, 2, 3) having a cell including the expected position (xj, yj, zj) of the high speed terminal MS_b_1 after T time, the high speed terminal MS_b_1. Calculate the expected stay time. Specifically, the movement distance within the cell of each of the base stations (xj, yj, zj) _RAN 1, 2, 3 of each RAN 1, 2, 3 is calculated from the movement speed of the high-speed terminal MS_b_1 and the expected movement route R. Then, based on the movement distance in the cell of each base station (xj, yj, zj) _RAN1,2,3 and the movement speed of the high-speed terminal MS_b_1, the cell of each base station (xj, yj, zj) _RAN1,2,3 Calculate the expected stay time in

  In step S22, the radio resource manager 3 compares the estimated stay times of the RANs 1, 2, and 3. In step S23, the radio resource manager 3 selects the RAN with the longest expected stay time as the accommodation destination candidate RAN of the high-speed terminal MS_b_1.

  If the moving speed is constant, the RAN having the longest moving distance may be selected as the accommodation destination candidate RAN by comparing only the moving distances in the same cell.

  Moreover, you may make it exclude RAN whose stay stay time is less than regulation value from accommodation destination candidate RAN.

  In addition, in the accommodation destination candidate RAN selection method of FIG. 9, the accommodation destination candidate RAN of the high speed terminal MS_b_1 is selected based on the expected time that the high speed terminal MS_b_1 stays in the same cell of the RAN. It is not limited to this. FIG. 10 is an example of the RAN selection criteria for explaining the accommodation destination candidate RAN selection method.

  In FIG. 10, it is assumed that there are two accommodation destination candidates RAN, RAN_A and RAN_B. In FIG. 10, the RSSI standard considering only RSSI and the RTT standard considering RSSI and delay (RTT) are shown as determination criteria. In a certain place, if both the reception strength RSSI_A of RAN_A and the reception strength RSSI_B of RAN_B are equal to or higher than the thresholds that can be used, if “RSSI_A> RSSI_B” according to the RSSI standard, select RAN_A, otherwise select RAN_B .

  On the other hand, in the case of real-time UGS applications such as voice communication, there are allowable upper limit values of RTT and jitter. For this reason, if the expected RTT of RAN_A and the expected RTT of RAN_B are both larger than the allowable upper limit, even if the RSSI standard is satisfied, it is not suitable for a real-time UGS application. Get out. In order to satisfy the RTT standard, it is necessary to take another measures such as increasing the amount of radio resources or searching for another RAN. If either the expected RTT of RAN_A or the expected RTT of RAN_B is smaller than the allowable upper limit value, the RAN is selected. If both the expected RTT of RAN_A and the expected RTT of RAN_B are smaller than the allowable upper limit value, the RAN having the smaller expected RTT is selected. As the predicted RTT, a statistical value (for example, an average value) of the actual RTT value in the cell can be used.

  In addition, as an accommodation destination candidate RAN selection method other than the above, for example, a method having the largest cell size can be selected. For example, when there is a macro cell RAN 1, a micro cell RAN 2, and a pico cell RAN 3 as the accommodation destination candidate RAN, the macro cell RAN 1 having the maximum cell size is selected. However, the larger cell size is not necessarily suitable as the accommodation destination candidate RAN depending on the moving speed and expected moving route of the terminal, the cell arrangement, and the like. In this regard, it is preferable to select the accommodation candidate RAN based on the expected stay time.

[Second Embodiment]
FIG. 11 is a configuration example of a mobile communication system according to the second embodiment of the present invention. In the second embodiment, one set of integrated radio resource manager 1 (integrated radio environment information database 2 and radio resource manager 3) is provided for one or a plurality of RANs. Further, a central cooperation unit 4 that centrally controls the integrated radio resource manager 1 is provided. The central cooperation unit 4 centrally controls the cooperation of radio resources for a plurality of radio resource managers 3. The centralized cooperation unit 4 can communicate with each integrated radio resource manager 1 and transmit / receive data to / from each integrated radio resource manager 1.

  FIG. 12 is a sequence diagram showing an overall procedure of the radio resource allocation control method according to the present embodiment. Here, for the sake of convenience, a specific example will be described using the example of FIG. Note that the integrated wireless environment information database 2 and the wireless resource manager 3 at the (xi, yi, zi) point are the integrated wireless environment information database 2i and the wireless resource manager 3i, and the integrated wireless environment information database at the (xj, yj, zj) point. 2. Let the wireless resource manager 3 be an integrated wireless environment information database 2j and a wireless resource manager 3j.

  In FIG. 12, in step S100i, the high-speed terminal MS_b_1 registers information such as a wireless state, a requested QoS, and a current location (xi, yi, zi) in the integrated wireless environment information database 2i. In step S100j, the terminals MS_a and b register information such as the wireless state, the requested QoS, and the current location (xj, yj, zj) in the integrated wireless environment information database 2j.

  In step S200i (S210i, S220i, S230i), RAN1,2,3 that can be accessed at the current location (xi, yi, zi) of the high-speed terminal MS_b_1 in response to a request from a functional block that controls the integrated wireless environment information database 2i. Each base station BS (xi, yi, zi) _RAN 1, 2, 3 registers the radio resource status (congestion information, location) in the integrated radio environment information database 2i. In step S200j (S210j, S220j, S230j), each base station of RAN 1, 2, 3 that can be accessed at a point (xj, yj, zj) in response to a request from a functional block that controls the integrated wireless environment information database 2j. BS (xj, yj, zj) _RAN1, 2, 3 registers the radio resource status (congestion information, location) in the integrated radio environment information database 2j.

  In step S301i, the radio resource manager 3i classifies the terminal and base station information in the integrated radio environment information database 2i, and calculates the moving speed of the high-speed terminal MS_b_1. In step S301j, the radio resource manager 3j classifies the terminal and base station information in the integrated radio environment information database 2i and calculates the moving speed of the terminals MS_a and b.

  In step S311i, the radio resource manager 3i transmits information such as the moving speed of the high-speed terminal MS_b_1, the expected moving route R, and the requested QoS to the centralized coordination unit 4. In step S311j, the central coordinating unit 4 transmits information such as the moving speed of the high-speed terminal MS_b_1, the expected moving route R, and the requested QoS to the radio resource manager 3j.

  In step S320, the radio resource manager 3j can access each base at the expected position (xj, yj, zj) of the high speed terminal MS_b_1 at a specific time (after T time) from the movement speed of the high speed terminal MS_b_1 and the expected movement route R. The movement distance in the cell of the station BS (xj, yj, zj) _RAN1, 2, 3 is calculated. Then, the radio resource manager 3j determines each base station (xj, yj) of the high-speed terminal MS_b_1 from the moving speed of the high-speed terminal MS_b_1 and the moving distance in the cell of each base station BS (xj, yj, zj) _RAN1,2,3. , Zj) The estimated stay time in the cells of _RAN1,2,3 is calculated. Further, the radio resource manager 3j calculates a radio resource requirement for satisfying the requested QoS of the high speed terminal MS_b_1 for each of the RANs 1, 2, and 3. Then, the radio resource manager 3j performs radio communication based on the radio resource status of each RAN 1, 2, 3 and the terminal accommodation status at the expected position (xj, yj, zj) of the high-speed terminal MS_b_1 at a specific time (after T time). A guideline for inter-RAN cooperation related to resource allocation is determined.

  In step S400 (S410, S420, S430), the radio resource manager 3j requests each base station BS (xj, yj, zj) _RAN1, 2, 3 to perform inter-RAN coordination related to radio resource allocation. At this time, when the RAN optimal for the high-speed terminal MS_b_1 (in this example, RAN1) is congested, the radio resource manager 3j has another terminal (for example, a terminal with a low priority) accommodated in the RAN1. ) To other RAN2 or 3 is tried.

  In step S501j, the radio resource manager 3j transmits the inter-RAN cooperation result related to radio resource allocation to the centralized coordination unit 4. In step S501i, the central cooperation unit 4 transmits the result of the inter-RAN cooperation related to the radio resource allocation to the radio resource manager 3i.

  In step S600 (S610, S620, S630), each base station BS (xj, yj, zj) _RAN1, 2, 3 performs radio resource allocation in response to a request from a functional block that controls the integrated radio environment information database 2j. The radio resource status (congestion information, location) as a result of the inter-RAN cooperation is registered in the integrated radio environment information database 2. In step S700, the radio resource manager 3i notifies the high-speed terminal MS_b_1 of the RAN (RAN1 in this example) that can be used at the destination (the expected position (xj, yj, zj) at the specific time (T time later)). To do.

  FIG. 13 shows a first embodiment of the base station 10 and the terminal 100 in the mobile communication system according to the present invention. In the first embodiment, the integrated radio environment information database 2 and the radio resource manager 3 are provided in the base station 10 corresponding to a plurality of RANs. The base station 10 includes radio modules 14a, 14b, and 14c corresponding to a plurality of RANs (macro cell, micro cell, and pico cell), a radio scheme selecting unit 13 that selects the radio modules 14a, 14b, and 14c, and a virtual MAC address. A virtual MAC processing unit 12 that performs processing for establishing the link used, a core network side interface 11 that transmits and receives network layer communication data (IP (Internet Protocol) packets) to and from the core network, and wireless quality information The wireless environment recognizing unit 15 that acquires the information, the integrated wireless environment information database 2, and the wireless resource manager 3. The configuration of the terminal 100 corresponds to the base station 10.

  The wireless environment recognition unit 15 includes an antenna 16 and acquires wireless quality information. The wireless environment recognition unit 15 stores the acquired wireless quality information in the integrated wireless environment information database 2. Radio quality information includes, for example, RSSI, background noise level, modulation method, amount of data waiting to be stored in the transmission buffer, number of times a NACK signal indicating transmission failure was received from the other station, and received from the other station For example, the defective rate of the radio frame.

  The radio resource manager 3 selects the accommodation destination candidate RAN of the terminal 100 based on the integrated radio environment information database 2 and notifies the radio scheme selection unit 13 of the selection result. The radio scheme selection unit 13 uses the radio module corresponding to the accommodation destination candidate RAN notified from the radio resource manager 3 for communication with the terminal 100. Note that the radio resource manager 3 may select a plurality of accommodation destination candidates RAN with priority, and supply information of the plurality of accommodation destination candidates RAN with priority to the radio scheme selection unit 13.

  FIG. 14 shows a second embodiment of the base station 10 and the terminal 100 in the mobile communication system according to the present invention. In the second embodiment, the integrated radio environment information databases 2 and 2U and the radio resource managers 3 and 3U are provided in each of the base station 10 and the terminal 100 corresponding to a plurality of RANs, and the radio resource manager 3U and the base station 10 of the terminal 100 are provided. Together with the radio resource manager 3, RAN is selected.

  The configuration of the base station 10 is the same as that of the first embodiment shown in FIG. The configuration of the terminal 100 is provided with an integrated wireless environment information database 2U and a wireless resource manager 3U in the first embodiment shown in FIG.

  In the terminal 100 of FIG. 14, the wireless environment recognition unit 105 includes an antenna 106 and acquires wireless quality information. The wireless environment recognition unit 105 stores the acquired wireless quality information in the integrated wireless environment information database 2U in the terminal 100. The radio quality information includes, for example, reception strength (for example, RSSI, SINR, CINR, etc.), base station ID, distance to the base station, modulation scheme, amount of data waiting to be stored in the transmission buffer, and transmission failure. The number of times the NACK signal is received from the partner station, the defect rate of the radio frame received from the partner station, and the like.

  Based on the integrated radio environment information database 2U in the terminal 100, the radio resource manager 3U in the terminal 100 selects the accommodation destination candidate RAN of the terminal 100 in cooperation with the radio resource manager 3 in the base station 10, and this selection result To the wireless system selection unit 103. The radio scheme selection unit 103 uses the radio module corresponding to the accommodation destination candidate RAN notified from the radio resource manager 3U for communication with the base station 10.

  In the above-described embodiment, the integrated wireless environment information database 2 includes the distribution status of terminals and base stations, the degree of congestion of radio resources of base stations, the position of terminals, and the movement characteristics of terminals (high-speed movement or low-speed movement or movement). A plurality of pieces of information such as the terminal movement (advance) direction, movement speed, predicted movement route, and the like. Then, the radio resource manager 3 calculates the expected position of the terminal at a specific time (after T time) based on the integrated radio environment information database 2 and estimates the distribution of the terminal. Further, the radio resource manager 3 estimates the ratio and distribution of terminals that move and terminals that do not move. Also, a terminal that needs to be handed over is predicted. Also, the radio resource manager 3 sends a RAN base station or AP (Access Point) of a different radio system at the expected position of the terminal at a specific time (after T time) to the terminal arrival probability, the terminal request QoS, Notify priority and reserve radio resources.

  In addition, it is estimated from the control channel etc. how many terminals can be accommodated in each heterogeneous radio system RAN and the radio resources can be allocated, and reflected in the integrated radio environment information database 2 and the radio resource manager 3, When switching to a single radio system RAN (handover), the radio system (RAN) is selected in order from the top of the candidate list. Here, it is possible to use a terminal initiative method in which a terminal has a neighbor list and a handover is initiated by a terminal, or a base station initiative autonomous method in which a handover is autonomously performed on the base station side. Alternatively, a centralized system in which the integrated wireless environment information database 2 and the radio resource margin, congestion degree information, and terminal information of each wireless system are centrally managed by the centralized cooperation unit 4 may be used. In any of these methods, the reserve radio resources are secured before the handover execution timing, so that the handover can be performed at high speed and stably.

According to the embodiment described above, the following effects can be obtained.
(1) In a situation where a plurality of RANs coexist, use an integrated wireless environment information database that stores distribution information of base stations and terminals, congestion information of each RAN, and communication quality information in association with map information. Correspondingly, radio resources between the RANs are allocated in a coordinated manner, and by selecting the RAN, it is possible to achieve both improvement in radio wave utilization efficiency and high reliability of communication.

(2) Depending on the effective allocation of radio resources, it is possible to improve the performance of the entire mobile communication system having a plurality of RANs, not just one RAN.
(3) It is possible to avoid communication interruptions associated with unexpected handovers and repeated retransmissions of radio sections, thereby realizing higher speed and more stable handovers.
(4) Analyzing the usage status and reservation status of the radio resources of the cell that can be used at the destination of the terminal based on the moving speed of the terminal and the requested QoS, and taking into account the number of handovers, high-speed terminals, especially high speed with high required QoS It is possible to allocate a macro cell radio resource capable of obtaining relatively stable communication quality to a terminal, and a micro cell or pico cell radio resource to a low speed terminal.

(5) It is possible to improve the frequency utilization efficiency of the entire mobile communication system configured by a plurality of RANs by coordinating between RAN cells of different types of radio systems.
(6) Since radio resources are allocated in consideration of a requested QoS including a request for an application delay and communication characteristics that can be provided by each RAN, wireless communication with higher reliability can be realized.
(7) Since switching between RANs can be predicted and preparation for switching can be performed in advance, smooth switching can be performed when a request for switching between RANs actually occurs.

Further, according to the first embodiment described above (one integrated radio resource manager 1 (centrally managed by one set of integrated radio environment information database 2 and radio resource manager 3)), the following effects can be obtained. .
Highly urgent wireless communications in the medical field (emergency treatment, ambulance-hospital communication) and response to critical personnel, and real-time wireless communications that want to avoid communication interruptions as much as possible (for example, wireless communications related to human life) In wireless communication that requires reliability, not only throughput but also delay is an important quality item.

  For example, it is assumed that the high-speed terminal MS_b_1 in FIG. 5 is an ambulance being dispatched. The ambulance MS_b_1 is scheduled to travel along the expected travel route R via the macrocells 350 and 310 and within the macrocell 320 via the (xj, yj, zj) point. The (xj, yj, zj) point is in a portion where the service areas of three cells of the macro cell 320, the micro cell in the macro cell 320, and the pico cell in the micro cell overlap.

  At this time, if the cells are simply switched according to the prescribed value of RSSI based on the received power intensity, for example, RSSI, between macro cell 320 and micro cell, between micro cell and pico cell, between pico cell and micro cell in FIG. Meanwhile, a total of four handovers between the micro cell and the macro cell 320 occur. This is a so-called Ping-Pong phenomenon. For this reason, delay occurs, and there is a possibility that sufficient quality cannot be maintained in voice communication of UGS class or ertPS class.

  However, according to the first embodiment, the centralized management by one integrated radio resource manager 1 can quickly calculate the expected stay time in each cell, and stay longer if there is a prospect of satisfying the communication quality. It is possible to secure radio resources for long-time cells. As a result, the occurrence of the ping-pong phenomenon can be prevented to prevent an increase in delay, and stable and high-quality wireless communication can be provided.

  In addition, when the terminal uses multiple applications, for example, in a situation where information on the sick person's situation and measures necessary for emergency are necessary at the same time, a doctor in the hospital will ask an emergency medical technician or doctor in the ambulance When instructing in real time, when it is necessary to perform real-time video communication (for example, transmission of electrocardiogram or blood pressure change data) in addition to voice calls, not only a single RAN but also multiple RANs should be used simultaneously. Is also possible.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the specific structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
For example, the present invention can be widely applied to the mobile communication field, such as a mobile phone system, an in-vehicle wireless system such as ITS, and a highly reliable wireless communication system for emergency medical use.

  Note that the present invention does not violate the provisions of IEEE P1900.4. When IRRM and IRED are allocated to the base station of each macrocell, IRRM corresponds to the functional block of P1900 NRM / TRM Information Extraction, Collection function and undefined Network Management Authority, Spectrum Assignment Evaluation, and IRED is PRM 1900 NRM. / TRM Information Extraction, Collection and Storage Function Block information provision and storage storage (database). The present invention can be applied as those examples.

DESCRIPTION OF SYMBOLS 1 ... Integrated radio | wireless resource manager (IRRM), 2 ... Integrated radio | wireless environment information database (IRED), 3 ... Radio | wireless resource manager (RRM), 4 ... Concentration cooperation part, 31 ... Expected stay time calculation part, 32 ... Radio | wireless resource condition estimation Part, 33 ... cooperative control part

Claims (14)

In a mobile communication system having a plurality of radio access network systems,
For each of the radio access network systems, an integrated radio environment information database that stores radio quality information representing radio quality at a specific location;
A radio access network system suitable for an expected movement path related to a specific terminal is selected based on the integrated radio environment information database, and radio resources are allocated so that radio resources are allocated to the terminal in cooperation between the selected radio access network systems. A radio resource manager that performs resource allocation control;
A mobile communication system comprising: The radio resource manager includes an expected stay time calculation unit that calculates an expected time for a specific terminal to stay in the same cell of the radio access network system.
The mobile communication system according to claim 1. The radio resource manager estimates a radio resource status at a specific time for each radio access network system having a cell including an expected position at a specific time related to a specific high-speed terminal having a speed equal to or higher than a specified rate. Having a part,
The mobile communication system according to claim 1 or 2, characterized by the above. The radio resource status estimation unit determines whether or not a radio resource requirement for satisfying the QoS requirement of the high-speed terminal can be allocated in the radio access network system to be estimated;
The mobile communication system according to claim 3. The radio resource status estimation unit determines whether a radio resource utilization rate related to the radio access network system to be estimated is a specified value or less,
The mobile communication system according to claim 3 or 4, characterized by the above. The radio resource manager
Based on the estimation result of the radio resource status, a cooperative control unit that attempts to change the accommodation of terminals between radio access network systems having cells including the expected position at the specific time,
The mobile communication system according to any one of claims 3 to 5, characterized in that The cooperative control unit is a radio for satisfying the QoS requirement of the high-speed terminal in a radio access network system in which the expected stay time of the high-speed terminal is the maximum among the radio access network systems having cells including the expected position at the specific time Attempt to replace the device to ensure resource requirements,
The mobile communication system according to claim 6. The cooperative control unit attempts to change accommodation of a terminal with a radio access network system having a radio resource utilization rate equal to or lower than a specified value among radio access network systems having a cell including an expected position at the specific time,
The mobile communication system according to claim 7.   The mobile communication system according to any one of claims 1 to 8, wherein the integrated radio environment information database and the radio resource manager are provided on a base station side. The integrated wireless environment information database and the wireless resource manager are also provided in the terminal,
The mobile communication system according to claim 9, wherein the radio resource manager of the terminal and the radio resource manager of the base station jointly select a radio access network system.   When the radio resource manager on the base station side and the radio resource manager of the terminal jointly perform radio resource management and radio access network system selection, the radio resource manager on the base station side takes the lead The mobile communication system according to claim 10.   The radio resource manager on the terminal side takes the lead when the radio resource manager on the base station side and the radio resource manager on the terminal jointly perform radio resource management and radio access network system selection. The mobile communication system according to claim 10.   When the radio resource manager on the base station side and the radio resource manager on the terminal jointly perform radio resource management and radio access network system selection, the radio resource manager on either the base station side or the terminal takes the lead. 11. The mobile communication system according to claim 10, wherein the radio resource manager on the base station side decides whether to do this based on a QoS level on the terminal side or a margin of a radio resource utilization rate. One set of the integrated radio environment information database and the radio resource manager for one or a plurality of radio access network systems;
The mobile communication system according to any one of claims 1 to 13, further comprising a central cooperation unit that centrally controls cooperation of radio resources for the plurality of radio resource managers.

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