JP5656615B2 - Wireless communication apparatus and control program therefor - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a technology that achieves both terminal demand and network load balancing for a multimode terminal that supports multiple wireless accesses.

  2. Description of the Related Art Conventionally, there are two types of utilization methods of multi-mode terminals corresponding to different types of radio systems: link switching that always selects an optimal radio link and link multiplexing that multiplexes a plurality of radio links. Conventionally, studies focusing on link switching have been performed on the assumption that there are abundant radio resources. However, it is difficult to ensure a desired quality with one link when radio resources are tight, such as during congestion. Therefore, link multiplexing that bundles the remaining radio resources of a plurality of radio systems and provides desired quality is required.

  In this regard, a technique for integrating different wireless systems such as a wireless LAN and a mobile phone has been proposed. For example, Patent Document 1 discloses a technology for integrating different types of radio systems having different cell sizes such as a pico cell, a micro cell, and a macro cell by using a cognitive base station and a cognitive terminal. The cognitive base station and the cognitive terminal include a switch, a plurality of wireless modules, and a wireless environment recognition unit. The wireless environment recognition unit recognizes the wireless environment, and based on the recognition result, the link frame is transmitted to the switch. Specify the wireless module that is the distribution destination. The link frame is transmitted / received via the designated wireless module. As a result, a study of a control method for a multi-access terminal that supports a plurality of radio accesses is underway.

  Non-Patent Document 1 proposes a method of selecting an access method that minimizes the amount of power consumption per received bit. Thereby, it is possible to select an access method with high power saving performance, and it is possible to improve the communication quality as compared with the conventional single access terminal. Non-Patent Document 2 proposes a method that uses AHP (hierarchical analysis method), scores a plurality of access methods from parameters such as bandwidth and delay, and switches the access method with the highest score. . Thereby, an access method can be selected in view of a balance of a plurality of qualities, and communication quality can be improved as compared with a conventional single access terminal.

JP 2008-85759 A

2009 IEICE Communication Society Conference B-17-22 “Power-saving Selection Method for Multimode Terminals”, Kanno et al. Telecommunications, 2007. ITST '07. 7th International Conference on ITS, "An Application-Oriented Cooperative Vertical Handoff Decision Method for Multi-interface Mobile Terminals", Shi Yan et al.

However, when the access method is selected only for the convenience of the terminal, inconvenience arises from the standpoint of the network. For example, when the terminal applies a selection policy that prioritizes hot spots, there is a problem that access concentrates on a specific access method. In addition, when a situation occurs in which multiple terminals move to an available access method at the same time, a situation occurs in which congestion occurs between access methods, access method switching occurs frequently, and access method selection is stable. The trouble of not doing occurs. In addition, when the terminal applies a selection policy that prioritizes a specific access method, there may be a problem that the terminal is concentrated and a loose access method is not selected even though other access methods are available. A possible cause of these situations is that the access method selection policy is constant regardless of the network situation.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a wireless communication apparatus capable of changing an access method selection policy included in a terminal according to a network situation and a control program thereof. To do.

  (1) In order to achieve the above object, the present invention takes the following measures. That is, the wireless communication device of the present invention is a wireless communication device applied to a heterogeneous wireless communication system that performs wireless communication by selecting at least one of a plurality of types of wireless communication methods, and different wireless communication devices. Based on a plurality of wireless modules that perform wireless communication with a method and acquire a plurality of types of information indicating a communication state, and a plurality of state information priorities that define different priorities for the acquired plurality of types of information, respectively An access selection unit that selects at least one of the wireless modules, and wireless transmission is performed by the selected wireless module.

  As described above, since at least one wireless module is selected based on a plurality of status information priorities each having different priorities for a plurality of types of information, the communication quality and network capacity of the wireless communication device It becomes possible to maintain a balance.

  (2) Further, in the wireless communication apparatus of the present invention, when the wireless communication method is changed, a change notification is transmitted to the communication partner.

  As described above, when the wireless communication system is changed, the change notification is transmitted to the communication partner, so that the wireless communication system can be switched smoothly.

  (3) Further, in the wireless communication device of the present invention, the access selection unit determines a congestion degree of a communication state using a congestion degree threshold value.

  As described above, it is possible to detect a change in the network state by determining the congestion degree of the communication state using the congestion degree threshold.

  (4) In the wireless communication device of the present invention, the access selection unit changes the congestion degree threshold or changes the priority among the plurality of state information according to the type of application. To do.

  Thus, according to the type of application, the congestion level threshold value is changed, or the priority among the plurality of state information is changed, so that it is possible to select a wireless communication method according to the type of application. Become.

  (5) The control program of the present invention is a control program for a wireless communication apparatus applied to a heterogeneous wireless communication system that performs wireless communication by selecting at least one of a plurality of types of wireless communication methods. A process of performing wireless communication using different wireless communication systems using a plurality of wireless modules, a process of acquiring a plurality of types of information indicating a communication state in each wireless module, and a plurality of types of acquired information respectively A series of processes including a process of selecting at least one wireless module and a process of performing wireless transmission with the selected wireless module based on a plurality of state information priorities with different priorities. It is characterized by being readable and executable as a command.

  As described above, since at least one wireless module is selected based on a plurality of status information priorities each having different priorities for a plurality of types of information, the communication quality and network capacity of the wireless communication device It becomes possible to maintain a balance.

  The present invention has an effect of maintaining a balance between the communication quality of each terminal and the network capacity, by changing the access method selection policy according to the network status and determining the access method of the terminal by the network. Further, load distribution can be realized by autonomously distributing terminals.

It is a block diagram which shows the network structure based on this invention. It is a block diagram which shows the structure of the terminal 1 of this invention. It is a block diagram which shows the structure of the high-order gateway 4 of this invention. It is a figure which shows the example which utilizes AHP (Analytic Hierarchy Process) as an access system selection method in the access system selection function 105 which concerns on the 1st Embodiment of this invention. It is a figure which shows the example which utilizes AHP (Analytic Hierarchy Process) as an access system selection method in the access system selection function 105 which concerns on the 1st Embodiment of this invention. It is a figure which shows the joint identical pair comparison matrix from the viewpoint of both the terminal 1 and NW which concerns on the 1st Embodiment of this invention. It is a control flowchart concerning the 1st embodiment of the present invention.

<First Embodiment>
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a network configuration according to the present invention. The network according to the present invention includes a terminal 1, a base station 2 for each access method, a gateway 3 for each access method, an upper gateway 4 that bundles a plurality of access methods, an external network (Internet network) 5, and an application server 6. The base station 2 and the gateway 3 by access method exist for each of the macro cell access method, the micro cell access method, and the pico cell access method.

  FIG. 2 is a block diagram showing the configuration of the terminal 1 of the present invention. The terminal 1 includes a wireless device (wireless module) 101 for each access method, a packet switch 103, an access method selection function (access selection unit) 105, and an upper layer function 107. The wireless device 101 has a function of performing wireless transmission and reception and a function of acquiring state information (a wireless state such as a congestion degree and a communication state such as a delay). The packet switch 103 transfers the uplink transmission packet (terminal 1 → base station 2) to the wireless device 101 of the access method selected by the access method selection function 105, and also receives the received packet in the downlink direction (base station 2 → terminal 1). Is transferred to the upper layer function 107. The access method selection function 105 acquires status information from the wireless device 101 and selects an access method based on this. Further, the selection result is notified to the packet switch 401 of the upper gateway 4 as a wireless change notification. The upper layer function 107 has functions such as a network layer, a transport layer, and an application layer.

  FIG. 3 is a block diagram showing the configuration of the upper gateway 4 of the present invention. There is a packet switch 401 between the external network 5 and the gateway 3 for each access method. The packet switch 401 performs packet routing between the external network 5 and the gateway 3 by access method. The downlink transmission packet (base station 2 → terminal 1) is transferred to the access method-specific gateway 3 corresponding to the access method notified by the radio change notification from the access method selection function 105, and the uplink transmission packet is transferred to an appropriate destination. . In addition, a response to the wireless change notification is transmitted to the packet switch 103.

  4 and 5 are diagrams illustrating an example in which AHP (Analytic Hierarchy Process) is used as an access method selection method in the access method selection function 105 according to the first embodiment of the present invention. In AHP, a pair comparison matrix of state information is set (steps S1 and S2 in FIG. 4), and a weight between the state information is obtained (step S3 in FIG. 4). Further, each time the status information is updated, an access method weight is obtained for each status information (step S4 in FIG. 5). By calculating the sum of products of these vectors, an access method score is calculated, priorities are determined in descending order, and the access method with the highest priority is selected (step S5 in FIG. 5).

  In the prior art, a constant relationship is always used as the priority between state information (step S1 in FIG. 4). For example, it is an example of the first network state in step S1 of FIG. In this embodiment, this is updated according to the network status. As in the second network state in step S1 of FIG. 4, the terminal 1 can prepare priorities between state information different from the first network state and can use them according to the network state.

  In FIG. 4, as a result of obtaining weights for two types of priority between state information, different weights are obtained in step S3. In FIG. 5, as a result of adapting the two types of weights to step S5, different priorities are obtained. In the case of the first network state, WiFi> LTE> WiMAX, and in the case of the second network state, LTE> WiFi> WiMAX, and different results are obtained.

  FIG. 6 is a diagram showing a joint pair comparison matrix from both the terminal 1 and NW viewpoints according to the first embodiment of the present invention. As an example different from the above, in FIG. 6, two types of priority between state information are prepared, and a paired comparison matrix obtained from each is prepared. One is referred to as a terminal pair comparison matrix from the viewpoint of the terminal 1, and the other is referred to as an NW pair comparison matrix from the network standpoint. The terminal pair comparison matrix is a matrix in which values are set so as to place importance on the communication quality of the terminal 1. Specifically, it is a matrix in which the specific gravity of parameters such as expected transmission rate and 1 / delay is increased. On the other hand, the NW pair comparison matrix is a matrix in which values are set in order to place importance on the capacity. Specifically, it is a matrix in which the specific gravity of parameters such as the degree of congestion and CINR is increased. By not selecting a low CINR access method, the use of self-fringing, which consumes a lot of radio resources, is avoided. A geometric mean matrix of both matrices is obtained, and a combined identical pair comparison matrix is obtained that takes into account the requests of both matrices. The weight may be obtained from this combined identical pair comparison matrix. The pair comparison matrix in the first network state shown in FIG. 4 is referred to as the terminal pair comparison matrix, and the pair comparison matrix in the second network state is referred to as the NW pair comparison matrix. The weights obtained from the both have a throughput of 0.18, a delay of 0.52, and a congestion degree of 0.3, indicating a compromise between the demands of both the terminal 1 and the NW. A plurality of NW paired comparison matrices may be prepared in accordance with network conditions, and geometric averaging may be performed each time, or the combined paired comparison matrix may be directly updated.

  A congestion degree threshold may be used for detecting a change in the network state. When terminal 1 can use M access methods (when located within the range of M access methods), the network state has changed when MN access methods are determined to be congested. It is considered. The situation where one access method is in a congested state can be dealt with without using this embodiment. When a plurality of access methods fall into a congested state at the same time, the congested state can be dealt with earlier by applying the method according to this embodiment. As the congestion level threshold, a different value may be set for each access method and for each base station 2. The degree of congestion is the resource usage rate (downlink, uplink), physical resource block (PRB) usage rate, slot usage rate, time occupancy rate, number of terminals in the cell / sector (data for transmission is Number of terminals staying in the buffer), number of terminals in active state (idle, number excluding sleep state, number of terminals assigned short identifiers, number of terminals associated), cell sector unit The total amount of transmission / reception data (the total amount of transmission data on the wireless side, the total amount of reception data, the total amount of transmission data on the wired side, the total amount of reception data), or the like may be used.

  FIG. 7 is a control flowchart according to the first embodiment of the present invention. The access method selection function 105 receives the correspondence between the priority between status information and the network status from the upper gateway 4 and holds it (step S101). The access method selection function 105 observes status information regularly or irregularly (step S102). The access method selection function 105 compares the state information with the correspondence information obtained in step S101, and obtains the weight of the state information (step S103). In this case, the weight may be obtained by switching the paired comparison matrix itself, the weight may be obtained after obtaining the combined paired comparison matrix from a plurality of paired comparison matrices, or the weight may be directly designated. When the access method selected as the first priority changes, the access method selection function 105 notifies the packet switch 401 of the higher gateway 4 of the ID of the new access method as a wireless change notification (step S104). The packet switch 401 transmits a response to the packet switch 103 (step S105). Each of the packet switch 103 and the packet switch 401 starts to transfer the transfer destination of the uplink transmission packet and the downlink transmission packet to the radio 101 of the access method selected by the access method selection function 105 and the gateway 3 by access method (step S106). .

  There is a derivation procedure for steps S104-S106. For example, when the terminal 1 always keeps a plurality of access methods in a connected state and there is a connection between the terminal 1 and the upper gateway 4, the step S <b> 105 may be omitted.

<Second Embodiment>
Derivative application examples of the first embodiment are shown below. The first embodiment may be applied individually for the downlink direction and the uplink direction, and an access method selection method that changes the weighting between the state information for each direction may be used. Alternatively, an access method selection method may be used in which the result of changing the weighting of the state information by applying the first embodiment to one direction of the downlink or uplink is applied to the remaining other direction. In this case, the application example of the first embodiment can be arranged into the following three types from the difference in the handling in the up direction and the down direction. (1) In the case of vertical symmetry (downlink-oriented), after selecting the downlink access method using the downlink state information, the same access method is also selected in the uplink direction. (2) In the case of vertical symmetry (uplink-oriented), after selecting the uplink access method using the uplink state information, the same access method is also selected in the downlink direction. (3) In the case of vertical asymmetry (uplink and downlink individually), the downlink access method is selected using the downlink state information, and the uplink access method is selected using the uplink state information. For example, when performing streaming viewing from the network (1), when performing live broadcast to the network (2), when performing interactive communication, (3), and the like can be used. Further, the threshold for detecting a change in the network status of the first embodiment is changed according to the type of application, or the weighting of the state information is applied by applying the first embodiment individually according to the type of application. The access method selection method for changing

1 Terminal 2 Base Station 3 Gateway by Access Method 4 Upper Gateway 5 External Network 6 Application Server 101 Radio 103 Packet Switch 105 Access Method Selection Function 107 Upper Layer Function 401 Packet Switch

Claims (5)

A wireless communication device applied to a heterogeneous wireless communication system that performs wireless communication by selecting at least one of a plurality of types of wireless communication methods,
A plurality of wireless modules that perform wireless communication using mutually different wireless communication methods, and obtain correspondence information of priority between status information and network status ;
Based on the acquired priority between the state information and the correspondence information of the network status, the weight between the state information and the weight of the wireless communication method are calculated, the weight of the wireless communication method for each state information is calculated, and the wireless communication method An access selection unit that calculates a score, determines priority in descending order of the score, and selects a wireless module corresponding to the wireless communication method with the highest priority ;
A wireless communication apparatus that performs wireless transmission with the selected wireless module.   The wireless communication apparatus according to claim 1, wherein when the wireless communication system is changed, a change notification is transmitted to the communication partner.   The wireless communication apparatus according to claim 1, wherein the access selection unit determines a congestion degree of a communication state using a congestion degree threshold.   The wireless communication apparatus according to claim 3, wherein the access selection unit changes the congestion level threshold or changes the priority among the plurality of state information in accordance with a type of application. A control program for a wireless communication device applied to a heterogeneous wireless communication system that performs wireless communication by selecting at least one of a plurality of types of wireless communication methods,
A process of performing wireless communication with different wireless communication systems using a plurality of wireless modules;
In each of the wireless modules, processing for obtaining correspondence information of priority between status information and network status ;
Based on the acquired priority between the state information and the correspondence information of the network status, the weight between the state information and the weight of the wireless communication method are calculated, the weight of the wireless communication method for each state information is calculated, and the wireless communication method A process of calculating a score, determining a priority in descending order of the score, and selecting a wireless module corresponding to the wireless communication method with the highest priority ;
A control program for a wireless communication apparatus, which causes a computer to execute a series of processing including wireless transmission using the selected wireless module.

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