Abstract:
An objective of the present invention is to provide a radio communication apparatus and a communication control method capable of executing processing including a handover appropriate for a communication quality of a radio link while suppressing an increase in development cost, when a handover controller is provided between a mobility manager and a link controller. An MIH function unit sets a communication quality threshold of a radio link in a radio link controller, the communication quality threshold being associated with a service quality requirement value notified by the mobility manager. The MIH function unit also notifies a mobility manager that the service quality requirement value corresponding to the communication quality threshold is satisfied, when being notified by the link controller that the communication quality of the radio link reaches the communication quality threshold.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2007-338144, filed on Dec. 27, 2007; the entire contents of which are incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a radio communication apparatus and a communication control method for executing a handover from a first radio communication network to a second radio communication network employing a different radio communication scheme from that employed by the first radio communication network. 
         [0004]    2. Description of the Related Art 
         [0005]    In recent years, along with advancement of radio communication technologies, a radio communication apparatus connectable to multiple radio communication networks employing different radio communication schemes has been put in practical use. 
         [0006]    Such a radio communication apparatus includes a media independent handover user (MIH user, or mobility manager) for managing mobility among multiple radio communication networks, and multiple link controllers for setting the radio communication networks and radio links respectively. 
         [0007]    Moreover, it has been proposed that a media independent handover function unit (MIH function unit, or handover controller) for controlling a handover between the radio communication networks (in other words, a handover between systems) is provided between the mobility manager and the multiple link controllers in the aforementioned radio communication apparatus connectable to the multiple communication networks (for example, IEEE P802.21/D04.00 Draft IEEE Standard for Local and Metropolitan Area Networks: Media Independent Handover Services, LAN MAN Standards Committee of the IEEE Computer Society (hereinafter, referred to as Non-Patent Document 1)). 
         [0008]    The method described in Non-Patent Document 1, however, has the following problems. Generally speaking, a higher layer entity such as the mobility manager or an application (IP phone, for example) is capable of determining degradation of quality of service (QoS) in the higher layer entity, but does not recognize the relationship between the degree of degradation and the communication quality of the radio link. For this reason, there is a problem that the radio communication apparatus cannot execute a handover at timing an appropriate for the communication quality of the radio link even though the radio communication apparatus is provided with the handover controller. Due to this problem, the quality of the application cannot be maintained adaptively. 
         [0009]    For the purpose of solving the aforementioned problem, the mobility manager may set a communication quality threshold in the handover controller to have a value appropriate for the communication quality of the radio link. Such a mobility manager, however, needs to be developed in consideration of each of the radio communication networks in terms of the processing procedure from the determination of the communication quality of the radio link to the execution of the handover. The development of the mobility manager taking all of the radio communication networks into consideration as described above raises another problem that the cost for the mobility manager increases. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention thus has been made in view of the situation described above. An objective of the present invention is thus to provide a radio communication apparatus and a communication control method capable of executing the processing including an appropriate handover corresponding to a communication quality of a radio link while suppressing an increase in development cost, in a case where a handover controller is provided between a mobility manager and link controllers. 
         [0011]    In order to resolve the aforementioned problems, the present invention has the following aspects. To begin with, a first aspect of the present invention is summarized as a radio communication apparatus (radio communication terminal  10 ) executing a handover from a first radio communication network (radio communication network  100 , for example) to a second radio communication network (radio communication network  200 , for example) employing a radio communication scheme different from the first radio communication network, the apparatus comprising: a link controller (radio link controllers  12 A to  12 C) configured to set a radio link (radio link RL) to one of the first radio communication network and the second radio communication network; a mobility manager (mobility manager  14 ) configured to manage a mobility of the radio communication apparatus from the first radio communication network to the second radio communication network; and a handover controller (MIH function unit  13 ) configured to control a handover from the first radio communication network to the second radio communication network, wherein the mobility manager notifies the handover controller of a service quality requirement value (required bandwidth (communication rate), for example) in a higher layer entity (higher layer entity  15 ) of the mobility manager, the handover controller sets a communication quality threshold (RSSI or CINR, for example) of the radio link to the link controller, the communication quality threshold being associated with the service quality requirement value notified by the mobility manager, and when the handover controller is notified by the link controller that a communication quality of the radio link reaches the communication quality threshold (Link_Parameters. Report. indication), the handover controller notifies the mobility manager that the service quality requirement value corresponding to the communication quality threshold is satisfied. 
         [0012]    According to the aforementioned radio communication apparatus, when the handover controller is notified by the link controller that the communication quality of the radio link set reaches the communication quality threshold, the handover controller notifies the mobility manager that the service quality requirement value corresponding to the communication quality threshold is satisfied (MIH_Link_Parameters_Report. indication). 
         [0013]    The mobility manager can thus promptly determine to change the service quality requirement value in the mobility manager or the service quality requirement value for the higher layer entity of the mobility manager, or to execute the handover, when being notified by the handover controller that the service quality requirement value is satisfied. 
         [0014]    Specifically, since the handover controller associates communication quality thresholds with service quality requirement values, the mobility manager does not have to recognize the relationship between each of the service quality requirement values and each of the communication quality thresholds dependent on the characteristics of the radio communication network. The mobility manager thus can execute processing such as a handover appropriate for the communication quality of the radio link on the basis of the service quality requirement values. In addition, since the mobility manager does not have to recognize the relationship between each of the communication quality thresholds and each of the service quality requirement values, which are dependent on the characteristics of the radio communication networks, the development cost of the mobility manager can be suppressed. 
         [0015]    A second aspect of the present invention is summarized as the radio communication apparatus according to the first aspect, wherein the link controller notifies (Link_Parameters_Report. indication) the handover controller that the communication quality reaches the communication quality threshold when the communication is quality of the radio link reaches the communication quality threshold set by the handover controller. 
         [0016]    A third aspect of the present invention is summarized as the radio communication apparatus according to one of the first and second aspects, wherein the mobility manager executes the handover when the mobility manger is notified by the handover controller that the the service quality requirement value is satisfied. 
         [0017]    A fourth aspect of the present invention is summarized as the radio communication apparatus according to one of the first and second aspects, wherein the mobility manager changes a setting content in the higher layer entity when the mobility manger is notified by the handover controller that the service quality requirement value is satisfied. 
         [0018]    A fifth aspect of the present invention is summarized as the radio communication apparatus according to one of the first and second aspects, wherein the handover controller sets a logical equation for determining whether or not the communication quality of the radio link reaches a predetermined threshold, to the link controller as the communication quality threshold. 
         [0019]    A sixth aspect of the present invention is summarized as a communication control method for a radio communication apparatus (radio communication terminal  10 ) including: an MIH user (mobility manager  14 ) configured to manage a mobility from a first radio communication network (radio communication network  100 , for example) to a second radio communication network (radio communication network  200 , for example) employing a radio communication scheme different from the first radio communication network; an MIH function unit (MIH function unit  13 ) configured to control a handover from the first radio communication network to the second radio communication network; and a link controller configured to set a radio link (radio link RL) with one of the first communication network and the second radio communication network, the method comprising the steps of: notifying the MIH function unit, by the MIH user, of a service quality requirement value (required bandwidth (communication rate), for example) of a communication service to be executed; setting, by the MIH function unit, a communication quality threshold (RSSI or CINR, for example) of the radio link to the link controller, the communication quality threshold being associated with the service quality requirement value notified by the MIH user; and notifying (MIH_Link_Parameters_Report. indication) the MIH user by the MIH function unit that the service quality requirement value corresponding to the communication quality threshold is satisfied, when the MIH function unit is notified (Link_Parameters_Report. indication) by the link controller that the communication quality of the radio link reaches the communication quality threshold. 
         [0020]    A seventh aspect of the present invention is summarized as the communication control method according to the sixth aspect, further comprising: the step of notifying (Link_Parameters_Report. indication) the MIH function unit by the link controller that the communication quality of the radio link reaches the communication quality threshold, when the communication quality of the radio link reaches the communication quality threshold set by the MIH function unit. 
         [0021]    According to the aspects of the present invention, it is possible to provide a radio communication apparatus and a communication control method capable of executing processing including a handover appropriate for the communication quality of a radio link while suppressing an increase in development cost, in a case where a handover controller I a provided between a mobility manager and link controllers. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1  is an overall schematic configuration diagram of a communication system  1  according to an embodiment of the present invention. 
           [0023]      FIG. 2  is a functional block configuration diagram of a radio communication terminal  10  according to the embodiment of the present invention. 
           [0024]      FIG. 3  is an internal sequence diagram when the radio communication terminal  10  according to the embodiment of the present invention executes a handover from a radio communication network  100  to a radio communication network  200  (Operation Example 1). 
           [0025]      FIG. 4  is an internal sequence diagram when the radio communication terminal  10  according to the embodiment of the present invention executes a handover from the radio communication network  100  to the radio communication network  200  (operation Example 2) 
           [0026]      FIG. 5  is a diagram showing a format of MIH_Configure_Link. request according to the embodiment of the present invention. 
           [0027]      FIG. 6  is a diagram showing a format of MIH_QoS_Threshold. request and a configuration example of MIH_QoS_Threshold. request according to the embodiment of the present invention. 
           [0028]      FIG. 7  is a diagram showing a format of Link_Configure_Threshold. request according to the embodiment of the present invention. 
           [0029]      FIG. 8  is a diagram showing a format of Link_Parameters_Report. indication according to the embodiment of the present invention. 
           [0030]      FIG. 9  is a diagram showing a format of MIH_Link_Parameters_Report. indication according to the embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0031]    Next, an embodiment of the present invention will be described. Specifically, descriptions will be given of (1) an overall schematic configuration of a communication system, (2) a functional block configuration of a radio communication terminal  10 , (3) an operation of the radio communication terminal  10 , (4) effects and advantages, and (5) other embodiments. 
         [0032]    Note that the same or similar portions are denoted by the same or similar reference numerals in the descriptions of the drawings below. It should be noted, however, that the drawings are schematic only, and that ratios of respective dimensions and the like differ from those in reality. 
         [0033]    Accordingly, specific dimensions and the like should be determined in consideration of the descriptions below. In addition, some of the dimensional relations and ratios differ in the drawings as a matter of course. 
       (1) Overall Schematic Configuration of Communication System 
       [0034]    As shown in  FIG. 1 , a communication system  1  according to the present embodiment is configured of a radio communication terminal  10  and multiple networks (radio communication networks  100 ,  200  and  300 ). 
         [0035]    The radio communication terminal  10  is capable of executing radio communications with the radio communication networks  100 ,  200  and  300 . Note that the radio communication terminal  10  will be described later in detail. 
         [0036]    The radio communication networks  100 ,  200  and  300  employ radio communication schemes (configurations of physical layers or link layers) different from each other. In this embodiment, the radio communication network  100  employs “1xEV-DO” compliant with CDMA2000. The radio communication network  200  employs “WiMAX” compliant with IEEE802.16e. The radio communication network  300  employs “WLAN” compliant with IEEE802.11. 
         [0037]    The radio communication terminal  10  is capable of executing a handover to another radio communication network on the basis of a communication quality of a radio link set with any one of the radio communication networks  100 ,  200  and  300 . 
       (2) Functional Block Configuration of Radio Communication Terminal  10    
       [0038]      FIG. 2  is a functional block configuration diagram of the radio communication terminal  10 . Note that  FIG. 2  shows functional blocks that are related to the present invention. Accordingly, it is to be noted that there is a case where the radio communication terminal  10  includes a logical block (such as a power supply) indispensable for performing functions as the device although such a logical block is not shown in the drawings, or the description thereof is omitted. 
         [0039]    As illustrated in  FIG. 2 , the radio communication terminal  10  includes radio communication units  11 A to  11 C, radio link controllers  12 A to  12 C, an MIH function unit  13 , a mobility manager  14  and a higher layer entity  15 . 
         [0040]    The radio communication units  11 A to  11 C set a physical radio connection in a physical layer for the radio communication networks  100 ,  200  and  300  in accordance with an instruction from a higher layer (the higher layer entity  15 , for example). 
         [0041]    Specifically, the radio communication unit  11  A sets a physical radio connection corresponding to “1xEV-DO” for the radio communication network  100 . The radio communication unit  11 B sets a physical radio connection corresponding to “WiMAX” for the radio communication network  200 . The radio communication unit  11 C sets a physical radio connection corresponding to “WLAN” for the radio communication network  300 . 
         [0042]    The radio link controllers  12 A to  12 C set a radio link RL in a link layer for the radio communication networks  100 ,  200  and  300  in accordance with an instruction from a higher layer (the higher layer entity  15 , for example). 
         [0043]    Specifically, the radio link controller  12 A has an interface function (device driver) with the radio communication unit  11 A and sets a radio link RL corresponding to “1xEV-DO” for the radio communication network  100 . The radio link controller  12 B has an interface function (device driver) with the radio communication unit  11 B and sets a radio link RL corresponding to “WiMAX” for the radio communication network  200 . The radio link controller  12 C has an interface function (device driver) with the radio communication unit  11 C and sets a radio link RL corresponding to “WLAN” for the radio communication network  300 . 
         [0044]    In addition, the radio link controller  12 A (and the radio link controllers  12 B and  12 C) acquires information indicating such as a communication quality of the radio link RL set for each radio communication network from the radio communication unit  11 A (and the radio communication units  11 B and  11 C). When the communication quality of the radio link RL reaches a communication quality threshold set by the MIH function unit  13 , the radio link controller  12 A (and the radio link controllers  12 B and  12 C) notifies the MIH function unit  13  that the communication quality of the radio link RL reaches the communication quality threshold. 
         [0045]    The MIH function unit  13  controls a handover between the radio communication networks in accordance with an instruction from the mobility manager  14 , which functions as a higher layer unit of the MIH function unit  13 . In this embodiment, the MIH function unit  13  constitutes a handover controller. The MIH function unit  13  is a media independent handover function, which is independent of the configuration of a physical layer, and is defined in IEEE802.21. 
         [0046]    The MIH function unit  13  includes “Radio Network Control,” which executes mapping of QoS parameters (bandwidth (communication rate), for example) to radio parameters (RSSI, for example) or setting of a logical equation for judgment of the communication quality in the link layer (L 2 ). 
         [0047]    The Radio Network Control sets two types of communication quality thresholds of a radio link RL and informs the radio link controller  12 A (and the radio link controllers  12 B and  12 C) of the set communication quality thresholds. Specifically, the Radio Network Control sets InitiateAction Threshold and ExecuteAction Threshold. InitiateAction Threshold is used to determine whether or not to execute a connection to the radio communication network of the handover destination. ExecuteAction Threshold is used to determine whether or not to execute a handover to the radio communication network. 
         [0048]    In other words, the MIH function unit  13  controls a handover from any one of the radio communication networks  100 ,  200  and  300  to another radio communication network. Specifically, the MIH function unit  13  sets the communication quality thresholds (InitiateAction Threshold and ExecuteAction Threshold) of the radio link RL in the radio link controllers  12 A to  12 C. The communication quality thresholds are associated with service quality requirement values (bandwidth (communication rate) required by the application currently executed, for example) notified by the mobility manager  14 . When the MIH function unit  13  is notified by the radio link controllers  12 A to  12 C that a communication quality of the radio link RL reaches a communication quality threshold, the MIH function unit  13  then notifies the mobility manager  14  that the communication quality of the radio link R reaches the service quality requirement value corresponding to the notified communication quality threshold. 
         [0049]    Alternatively, the MIH function unit  13  is also capable of setting the logical equation for judgment for each radio link RL, a logical equation being used to judge whether or not the communication quality of the radio link RL reaches a predetermined threshold as the communication quality threshold. Specifically, the MIH function unit  13  stores contents shown in Tables 10 to 12 to be described later and then sets logical equations for judgment in accordance with the contents stored in the MIH function unit  13 . 
         [0050]    The mobility manager  14  manages the mobility of the radio communication terminal  10 . Specifically, the mobility manager  14  manages the mobility of the radio communication terminal  10  among the radio communication networks  100 ,  200  and  300 . For example, the mobility manager  14  manages the mobility of the radio communication terminal  10  from the radio communication network  100  to the radio communication network  200 . 
         [0051]    The mobility manager  14  notifies the MIH function unit  13  of a service quality requirement value of a communication service being executed in the higher layer entity  15 , which is provided at a layer higher than that of the mobility manager  14 . 
         [0052]    The mobility manager  14  is capable of executing a handover to another radio communication network when the mobility manager  14  is notified by the MIH function unit  13  that the communication is quality of the radio link RL reaches the communication quality threshold associated with the service quality requirement value. In addition, the mobility manager  14  is also capable of causing the higher layer entity  15  change a setting content (encoding rate of the codes used in an IP phone application, for example), when the mobility manager  14  is notified by the MIH function unit  13  that the communication quality of the radio communication link RL reaches the communication quality threshold associated with the service quality requirement value. 
         [0053]    The higher layer entity  15  is provided at a layer higher than that of the mobility manager  14 . The higher layer entity  15  is constituted of the fourth layer protocol such as TCP, Network Management Protocol such as Mobile IP, an IP application (IP phone application, for example), a communication path selection policy and the like. 
         [0054]    In this embodiment, the mobility manager  14  and the higher layer entity  15  cooperatively function as an MIH User defined in IEEE802.21. Note that the higher layer entity  15  may be configured to function as a part of the mobility manager  14 . 
       (3) Operation of Radio Communication Terminal  10   
       [0055]    Next, an operation of the aforementioned radio communication terminal  10  will be described. Specifically, a description will be given of the operation of the radio communication terminal  10  for executing a handover from the radio communication network  100  to the radio communication network  200 . 
       (3.1) Operation Example 1  
       [0056]      FIG. 3  is an internal sequence diagram when the radio communication terminal  10  executes a handover from the radio communication network  100  to the radio communication network  200 . Note that in this embodiment, the radio communication terminal  10  operates in accordance with the procedure defined in IEEE802.21. 
         [0057]    As shown in  FIG. 3 , in step S 101 , the higher layer entity  15  transmits a QoS parameter and policy information (QoS Requirement) required by the application currently in execution to the mobility manager  14 . Note that the higher layer entity  15  may be configured to function as a part of the mobility manager  14  as described above. In this case, the mobility manager  14  includes the QoS parameter and policy information. The QoS parameters are the required bandwidth (communication rate) for the application, allowable delay time and fluctuation in arrival time of received packets, and the like. Moreover, the policy information is the selection policy of a communication path in accordance with the application, the security level required by the radio communication network to be connected, or the like. 
         [0058]    In step S 103 , the mobility manager  14  transmits MIH_Configure_Link. request to the MIH function unit  13  in order to prepare for the case where a handover is executed on the basis of the communication quality of the radio communication network for which the radio link RL is currently set. 
         [0059]      FIG. 5  shows a format of MIH_Configure_Link. request. Moreover, Tables 1 and 2 show the content of each parameter included in MIH_Configure_Link. request. 
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Name 
                 Type 
                 Valid range 
                 Description 
               
               
                   
               
             
             
               
                 Destination Identifier 
                 MIHF ID 
                 N/A 
                 This identifies the local MIHF or a remote MIHF which will 
               
               
                   
                   
                   
                 be the destination of this request. 
               
               
                 Link Identifier 
                 LINK ID 
                 N/A 
                 Identifier of the link to be configured 
               
               
                 Configuration Requests List 
                 LIST 
                 N/A 
                 List of Configuration Requests, as defined in Table 42 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Table 42 - Elements of configuration request 
               
             
          
           
               
                 Name 
                 Type 
                 Valid range 
                 Description 
               
               
                   
               
               
                 Configuration Parameter 
                 INTEGER 
                 N/A 
                 Type of parameter to be configured 
               
               
                 Type 
                   
                   
                 0: Operation Mode 
               
               
                   
                   
                   
                 1: Link QoS Parameter List 
               
               
                   
                   
                   
                 2: Link Configure List 
               
               
                   
                   
                   
                 3: 255(Reserved) 
               
               
                 Configuration Parameter 
                 Varies depending on 
                 N/A 
                 Value of the parameter being set as defined in 
               
               
                 Value 
                 the parameter type 
                   
                 Table 43. 
               
               
                   
               
             
          
         
       
     
         [0060]    MIH_Configure_Link. request includes Configure parameter type and Configure parameter value (refer to Table 2). Furthermore, Handover Parameter for link quality degradation is added as a new element in MIH_Configure_Link. request (Link Configuration Parameter Value) in this embodiment (refer to Tables 3 to 5). Note that hereinafter, underlined portions in Tables indicate that the a portions are added for the contents defined in IEEE802.21. 
         [0000]    
       
         
               
             
               
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 Table 43 Link configuration parameter values 
               
             
          
           
               
                 Name 
                 Type 
                 Valid range 
                 Description 
               
               
                   
               
               
                 Operation Mode 
                 INTEGER 
                 N/A 
                 0: Power Up 
               
               
                   
                   
                   
                 1: Power Saving Mode 
               
               
                   
                   
                   
                 2: Power Down 
               
               
                 Link QoS Parameter List 
                 LIST 
                 N/A 
                 A list of link QoS parameters and their corresponding 
               
               
                   
                   
                   
                 values as specified Table 12 
               
               
                 Link Configuration 
                 LIST 
                 N/A 
                 A list of link parameters and their corresponding thresholds 
               
               
                 Parameter List 
                   
                   
                 as defined in 
               
               
                   
                   
                   
                 “Link_Configure_Threshold.request” 
               
               
                 Handover Parameter for 
                 LIST 
                 N/A 
                 Wireless Access NW Quality Degradation Threshold 1 
               
               
                 link quality degradation 
                   
                   
                 Wireless Access NW Quality Degradation Threshold 2 
               
               
                   
                   
                   
                 Threshold 1 corresponds to trigger of handover 
               
               
                   
                   
                   
                 preparation such as establish a new link for handover 
               
               
                   
                   
                   
                 while threshold 2 corresponds to trigger of handover 
               
               
                   
                   
                   
                 execution. 
               
               
                   
                   
                   
                 Note: Two thresholds are decided by MIHF. 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
               
             
           
               
                 TABLE 4 
               
             
             
               
                   
               
               
                 Table 12 - QoS parameter encoding 
               
             
          
           
               
                 Syntax 
                 length 
                 Note 
               
               
                   
               
               
                 QoS Parameter Type 
                 2 
                 The type of QoS parameter as defined 
               
               
                   
                   
                 In Table 13 
               
               
                 QoS Parameter Value 
                 Variable 
                 The parameter value is dependent on 
               
               
                   
                   
                 the parameter type. For generic QoS 
               
               
                   
                   
                 parameters, the encoding is defined 
               
               
                   
                   
                 in Table 14 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
               
             
           
               
                 TABLE 5 
               
             
             
               
                   
               
               
                 Table 13 - QoS parameter type encoding 
               
             
          
           
               
                 Syntax 
                 length 
                 Note 
               
               
                   
               
               
                 QoS Link 
                 1 
                 The network type for the QoS Parameter. 
               
               
                 Family 
                   
                 Type 0 indicates Generic link type. Other 
               
               
                   
                   
                 values are defined in Table 9 
               
               
                 QoS Parameter 
                 1 
                 The subtype of QoS parameter. 
               
               
                 subtype 
                   
                 The QoS parameters for the Generic link type: 
               
               
                   
                   
                 0: Number of supported QoS 
               
               
                   
                   
                 1: Throughput (kbps) 
               
               
                   
                   
                 2: Packer Error Rate 
               
               
                   
                   
                 3: CoS Minimum Packet Transfer Delay (ms) 
               
               
                   
                   
                 4: CoS Average Packet Transfer Delay (ms) 
               
               
                   
                   
                 5: CoS Maximum Packet Transfer Delay (ms) 
               
               
                   
                   
                 6: CoS Packet Transfer Delay Jitter (ms) 
               
               
                   
                   
                 7: CoS Packet Loss Rate 
               
               
                   
                   
                 8-255: Reserved 
               
               
                   
               
             
          
         
       
     
         [0061]    As shown in Table 3, Handover Parameter for link quality degradation includes NW Quality Degradation Threshold  1  and NW Quality Degradation Threshold  2  to be applied to the radio communication network for which the current radio link RL is set. Note that MIH_Configure_Link. request can consider and define one service equality requirement value in addition to the threshold condition of the communication quality thresholds (InitiateAction Threshold, ExecuteAction Threshold) defined in IEEE802.21. 
         [0062]    Note that the mobility manager  14  is not involved with the setting of specific values of NW Quality Degradation Threshold  1  and NW Quality Degradation Threshold  2 . The specific values of NW Quality Degradation Threshold  1  and NW Quality Degradation Threshold  2  are set in the MIH function unit  13 . NW Quality Degradation Threshold  1  is used to determine whether or not to start a connection to the radio communication network of the handover destination. NW Quality Degradation Threshold  2  is used to determine whether or not to actually execute a handover. 
         [0063]    In step S 105 , the mobility manager  14  can notify the MIH function unit  13  of multiple service quality requirement values (for example, Bandwidth: 4 kbps, 8 kbps, 12 kbps and so forth) on the basis of the QoS parameters and policy information transmitted from the higher layer entity  15 . Specifically, the mobility manager  14  transmits MIH_QoS_Threshold. request to the MIH function unit  13 . 
         [0064]      FIG. 6  shows a format of MIH_QoS_Threshold. request and a configuration example of MIH_QoS_Threshold. request. MIH_QoS_Threshold. request is used when a communication service or an IP application to be executed in the higher layer entity  15  requests a handover to the MIH function unit  13  or control of each type of parameters without using the threshold condition with the communication quality thresholds (InitiateAction Threshold, ExecuteAction Threshold). 
         [0065]    In step S 107 , the MIH function unit  13  transmits, to the radio link controller  12 A, the communication quality thresholds (InitiateAction Threshold, Execution Threshold, for example) in the lower layer (L 2 ) or the communication quality threshold corresponding to the service quality requirement value on the basis of MIH_Configure_Link.requset or MIH_QoS_Threshold. request transmitted from the mobility manager  14 . 
         [0066]    Specifically, the MIH function unit  13  transmits Link_Configure_Threshold. request to the radio link controller  12 A. Note that when the MIH function unit  13  receives MIH_QoS_Threshold. request from the mobility manager  14 , the MIH function unit  13  includes the communication quality threshold (such as RSSI ox CINR) of the link layer (L 2 ) corresponding to the service quality requirement value into Link_Configure_Threshold. request and then transits Link_Configure_Threshold. request to the radio link controller  12 A. In other words, in step S 109 , the MIH function unit  13  sets the communication quality threshold of the lower layer (L 2 ) corresponding to the service quality requirement value on the basis of the service quality requirement value transmitted from the mobility manager  14 . 
         [0067]      FIG. 7  shows a format of Link_Configure_Threshold. request. Tables 6 to 9 show the content of each parameter included in Link_Configure_Threshold. request. NW Quality Degradation Threshold  1  described above corresponds to InitiateAction Threshold and NW Quality Degradation Threshold  2  described above corresponds to ExecuteAction Threshold in Link_Configure_Threshold. request. 
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 6 
               
               
                   
               
               
                 Name 
                 Type 
                 Valid Range 
                 Description 
               
               
                   
               
             
             
               
                 Link Parameter List 
                 List 
                 N/A 
                 A list of following set of parameters: 
               
               
                   
                   
                   
                 Link Parameter Type, 
               
               
                   
                   
                   
                 Initiate Action Threshold, 
               
               
                   
                   
                   
                 Rollback Action Threshold, 
               
               
                   
                   
                   
                 Execute Action Threshold, 
               
               
                   
                   
                   
                 Logical equation to Judge listed parameters, 
               
               
                   
                   
                   
                 Interval for Judgment 
               
               
                 Link Parameter Type 
                 A pair of {Link Type:ParamType} 
                 N/A 
                 Parameters for which thresholds may be set. 
               
               
                   
                 Examples: 
               
               
                   
                 {Generic SINR}, 
               
               
                   
                 {Generic RSSI}, 
               
               
                   
                 {EV-DO:DRC}, 
               
               
                   
                 {EV-DO:Tx_Power}, 
               
               
                   
                 {EV-DO:DRC_Lock} 
               
               
                 Priority of Link 
                 Each Link name is followed by Priority 
                 N/A 
                 Priority is described per Link. 
               
               
                   
                 value {lower value means higher priority} 
               
               
                   
                 Examples: 
               
               
                   
                 CDMA2000 1xEV-DO = 1 
               
               
                   
                 WiFi = 2 
               
               
                   
                 IEEE 802.16e = 3 
               
               
                 Initiate Action Threshold 
                 Threshold values are dependent on 
                 N/A 
                 Threshold value which may MIHF Users to start “setup 
               
               
                   
                 parameter for which they are being set. 
                   
                 type activities in response to actual parameter values 
               
               
                   
                   
                   
                 crossing this threshold. 
               
               
                 Execute Action Threshold 
                 Threshold values are dependent on 
                 N/A 
                 Threshold value which may cause MIHF Users to execute 
               
               
                   
                 parameter for which they are being set 
                   
                 taking appropriate action if the actual parameter values 
               
               
                   
                   
                   
                 cross this threshold. 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 7 
               
               
                   
               
               
                   
                   
                 Valid 
                   
               
               
                 Name 
                 Type 
                 Range 
                 Description 
               
               
                   
               
             
             
               
                 Logical equation to judge 
                 Logical equation for Initiate Action 
                 N/A 
                 Logical equation by which MIHF may judge each 
               
               
                 listed parameters with 
                   
                   
                 multiple parameters that cross the 
               
               
                 Initiate Action Threshold 
                   
                   
                 Initiate Action Threshold. 
               
               
                   
                   
                   
                 If equation is met, Link_Parameters_Report.indication 
               
               
                   
                   
                   
                 will be sent to MIHF. 
               
               
                 Logical equation to judge 
                 Logical equation for Execute Action 
                 N/A 
                 Logical equation by which MIHF may judge each 
               
               
                 listed Parameter with 
                   
                   
                 multiple parameters that cross the 
               
               
                 Execute Action Threshold 
                   
                   
                 Execute Action Threshold. 
               
               
                   
                   
                   
                 If equation is met, Link_Parameters_Report.Indication 
               
               
                   
                   
                   
                 will be sent to MIHF. 
               
               
                 Interval for judgment 
                 Interval time 
                 N/A 
                 Interval time during which each parameters are 
               
               
                   
                   
                   
                 collected and logical equation are evaluated. 
               
               
                 QoS_Related_Threshold 1 
                 Threshold values are dependent on 
                 N/A 
                 Threshold value which may cause MIH User to 
               
               
                   
                 parameter for which they are being set 
                   
                 appropriate QoS action. 
               
               
                 QoS_Related_Threshold 2 
                 Threshold values are dependent on 
                 N/A 
                 Threshold value which may cause MIH User to 
               
               
                   
                 parameter for which they are being set 
                   
                 appropriate QoS action. 
               
               
                 QoS_Related_Threshold 3 
                 Threshold values are dependent on 
                 N/A 
                 Threshold value which may cause MIH User to 
               
               
                   
                 parameter for which they are being set 
                   
                 appropriate QoS action. 
               
               
                 QoS_Related_Threshold 4 
                 Threshold values are dependent on 
                 N/A 
                 Threshold value which may cause MIH User to 
               
               
                   
                 parameter for which they are being set 
                   
                 appropriate QoS action. 
               
               
                 QoS_Related_Threshold 5 
                 Threshold values are dependent on 
                 N/A 
                 Threshold value which may cause MIH User to 
               
               
                   
                 parameter for which they are being set 
                   
                 appropriate QoS action. 
               
               
                 QoS_Related_Threshold 6 
                 Threshold values are dependent on 
                 N/A 
                 Threshold value which may cause MIH User to 
               
               
                   
                 parameter for which they are being set 
                   
                 appropriate QoS action. 
               
               
                 QoS_Related_Threshold 7 
                 Threshold values are dependent on 
                 N/A 
                 Threshold value which may cause MIH User to 
               
               
                   
                 parameter for which they are being set 
                   
                 appropriate QoS action. 
               
               
                 QoS_Related_Threshold 8 
                 Threshold values are dependent on 
                 N/A 
                 Threshold value which may cause MIH User to 
               
               
                   
                 parameter for which they are being set 
                   
                 appropriate QoS action. 
               
               
                 QoS_Related_Threshold 9 
                 Threshold values are dependent on 
                 N/A 
                 Threshold value which may cause MIH User to 
               
               
                   
                 parameter for which they are being set 
                   
                 appropriate QoS action. 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 8 
               
               
                   
               
               
                   
                   
                 Valid 
                   
               
               
                 Name 
                 Type 
                 Range 
                 Description 
               
               
                   
               
             
             
               
                 Logical equation to judge 
                 Logical equation 
                 N/A 
                 Logical equation by which MIHF may judge each 
               
               
                 listed parameters for 
                   
                   
                 multiple parameters that cross the each Thresholds 
               
               
                 QoS_Related_Threshold 1 
                   
                   
                 for QoS. 
               
               
                   
                   
                   
                 If equation is met, Link_Parameters_Report.indication 
               
               
                   
                   
                   
                 will be sent to MIHF. 
               
               
                 Logical equation to judge 
                 Logical equation 
                 N/A 
                 Logical equation by which MIHF may judge each 
               
               
                 listed parameters for 
                   
                   
                 multiple parameters that cross the each Thresholds 
               
               
                 QoS_Related_Threshold 2 
                   
                   
                 for QoS. 
               
               
                   
                   
                   
                 If equation is met, Link_Parameters_Report.indication 
               
               
                   
                   
                   
                 will be sent to MIHF. 
               
               
                 Logical equation to judge 
                 Logical equation 
                 N/A 
                 Logical equation by which MIHF may judge each 
               
               
                 listed parameters for 
                   
                   
                 multiple parameters that cross the each Thresholds 
               
               
                 QoS_Related_Threshold 3 
                   
                   
                 for QoS. 
               
               
                   
                   
                   
                 If equation is met, Link_Parameters_Report.indication 
               
               
                   
                   
                   
                 will be sent to MIHF. 
               
               
                 Logical equation to judge 
                 Logical equation 
                 N/A 
                 Logical equation by which MIHF may judge each 
               
               
                 listed parameters for 
                   
                   
                 multiple parameters that cross the each Thresholds 
               
               
                 QoS_Related_Threshold 4 
                   
                   
                 for QoS. 
               
               
                   
                   
                   
                 If equation is met, Link_Parameters_Report.indication 
               
               
                   
                   
                   
                 will be sent to MIHF. 
               
               
                 Logical equation to judge 
                 Logical equation 
                 N/A 
                 Logical equation by which MIHF may judge each 
               
               
                 listed parameters for 
                   
                   
                 multiple parameters that cross the each Thresholds 
               
               
                 QoS_Related_Threshold 5 
                   
                   
                 for QoS. 
               
               
                   
                   
                   
                 If equation is met, Link_Parameters_Report.indication 
               
               
                   
                   
                   
                 will be sent to MIHF. 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 9 
               
               
                   
               
               
                   
                   
                 Valid 
                   
               
               
                 Name 
                 Type 
                 Range 
                 Description 
               
               
                   
               
             
             
               
                 Logical equation to judge 
                 Logical equation 
                 N/A 
                 Logical equation by which MIHF may judge each 
               
               
                 listed parameters for 
                   
                   
                 multiple parameters that cross the each Thresholds 
               
               
                 QoS_Related_Threshold 6 
                   
                   
                 for QoS. 
               
               
                   
                   
                   
                 If equation is met, Link_Parameters_Report.indication 
               
               
                   
                   
                   
                 will be sent to MIHF. 
               
               
                 Logical equation to judge 
                 Logical equation 
                 N/A 
                 Logical equation by which MIHF may judge each 
               
               
                 listed parameters for 
                   
                   
                 multiple parameters that cross the each Thresholds 
               
               
                 QoS_Related_Threshold 7 
                   
                   
                 for QoS. 
               
               
                   
                   
                   
                 If equation is met, Link_Parameters_Report.indication 
               
               
                   
                   
                   
                 will be sent to MIHF. 
               
               
                 Logical equation to judge 
                 Logical equation 
                 N/A 
                 Logical equation by which MIHF may judge each 
               
               
                 listed parameters for 
                   
                   
                 multiple parameters that cross the each Thresholds 
               
               
                 QoS_Related_Threshold 8 
                   
                   
                 for QoS. 
               
               
                   
                   
                   
                 If equation is met, Link_Parameters_Report.indication 
               
               
                   
                   
                   
                 will be sent to MIHF. 
               
               
                 Logical equation to judge 
                 Logical equation 
                 N/A 
                 Logical equation by which MIHF may judge each 
               
               
                 listed parameters for 
                   
                   
                 multiple parameters that cross the each Thresholds 
               
               
                 QoS_Related_Threshold 9 
                   
                   
                 for QoS. 
               
               
                   
                   
                   
                 If equation is met, Link_Parameters_Report.indication 
               
               
                   
                   
                   
                 will be sent to MIHF. 
               
               
                   
               
               
                 Note: 
               
               
                 RollbackActionThreshold is deleted. 
               
             
          
         
       
     
         [0068]    The MIH function unit  13  performs mapping of a logical equation for judgment on each of the service quality requirement values on the basis of the QoS parameters and policy information in the higher layer entity  15 , and then transmits the mapped service quality requirement values and the logical equations for judgment to the radio link controllers  12 A to  12 C as the threshold conditions of the quality of service (QoS). 
         [0069]    Tables 10 to 12 show specific examples of Link_Configure_Threshold. request. 
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 10 
               
               
                   
                   
               
               
                   
                 Radio Communication Network 100 
                 Radio Communication Network 200 
                 Radio Communication Network 300 
               
               
                   
                 (e.g. CDMA 1x EV-DO) 
                 (e.g. IEEE 802.16e) 
                 (e.g. WLAN) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Radio Parameter for 
                 {Previous Rate, Previous 
                 {Rate, CINR} 
                 {Rate, CIR} 
               
               
                 QoS Related Threshold 1 (4 kbps) 
                 DRC, Current DRC} 
               
               
                 Logical Equation for Judgment 
                 P = Current DRC * Previous 
                 Rate ≦ 4 kbps 
                 Rate ≦ 4 kbps 
               
               
                   
                 Rate/Previous DRC * Fr ≦ 
                 &amp; CINR ≦ −2 dB 
                 &amp; CINR ≦ −2 dB 
               
               
                   
                 4 kbps 
               
               
                 Interval for Judgment 
                 500 ms 
                 500 ms 
                 500 ms 
               
               
                 Radio Parameter for 
                 {Previous Rate, Previous 
                 {Rate, CINR} 
                 {Rate, CIR} 
               
               
                 QoS Related Threshold 2 (8 kbps) 
                 DRC, Current DRC} 
               
               
                 Logical Equation for Judgment 
                 P = Current DRC * Previous 
                 Rate ≦ 8 kbps 
                 Rate ≦ 8 kbps 
               
               
                   
                 Rate/Previous DRC * Fr ≦ 
                 &amp; CINR ≦ −1 dB 
                 &amp; CINR ≦ −1 dB 
               
               
                   
                 8 kbps 
               
               
                 Interval for Judgment 
                 500 ms 
                 500 ms 
                 500 ms 
               
               
                 Radio Parameter for 
                 {Previous Rate, Previous 
                 {Rate, CINR} 
                 {Rate, CIR} 
               
               
                 QoS Related Threshold 3 (12 kbps) 
                 DRC, Current DRC} 
               
               
                 Logical Equation for Judgment 
                 P = Current DRC * Previous 
                 Rate * Fr ≦ 12 kbps 
                 Rate * Fr ≦ 12 kbps 
               
               
                   
                 Rate/Previous DRC * Fr ≦ 
                 &amp; CINR ≦ 0 dB 
                 &amp; CINR ≦ 0 dB 
               
               
                   
                 12 kbps 
               
               
                 Interval for Judgment 
                 500 ms 
                 500 ms 
                 500 ms 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 11 
               
               
                   
                   
               
               
                   
                 Radio Communication Network 100 
                 Radio Communication Network 200 
                 Radio Communication Network 300 
               
               
                   
                 (e.g. CDMA 1x EV-DO) 
                 (e.g. IEEE 802.16e) 
                 (e.g. WLAN) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Radio Parameter for 
                 {Previous Rate, Previous 
                 {Rate, CINR} 
                 {Rate, CIR} 
               
               
                 QoS Related Threshold 4 (16 kbps) 
                 DRC, Current DRC} 
               
               
                 Logical Equation for Judgment 
                 P = Current DRC * Previous 
                 Rate * Fr ≦ 16 kbps 
                 Rate * Fr ≦ 16 kbps 
               
               
                   
                 Rate/Previous DRC * Fr ≦ 
                 &amp; CINR ≦ 1 dB 
                 &amp; CINR ≦ 1 dB 
               
               
                   
                 16 kbps 
               
               
                 Interval for Judgment 
                 500 ms 
                 500 ms 
                 500 ms 
               
               
                 Radio Parameter for 
                 {Previous Rate, Previous 
                 {Rate CINR} 
                 {Rate, CIR} 
               
               
                 QoS Related Threshold 5 (24 kbps) 
                 DRC, Current DRC} 
               
               
                 Logical Equation for Judgment 
                 P = Current DRC * Previous 
                 Rate * Fr ≦ 24 kbps 
                 Rate * Fr ≦ 24 kbps 
               
               
                   
                 Rate/Previous DRC * Fr ≦ 
                 &amp; CINR ≦ 2 dB 
                 &amp; CINR ≦ 2 dB 
               
               
                   
                 24 kbps 
               
               
                 Interval for Judgment 
                 500 ms 
                 500 ms 
                 500 ms 
               
               
                 Radio Parameter for 
                 {Previous Rate, Previous 
                 {Rate, CINR} 
                 {Rate, CIR} 
               
               
                 QoS Related Threshold 6 (32 kbps) 
                 DRC, Current DRC} 
               
               
                 Logical Equation for Judgment 
                 P = Current DRC * Previous 
                 Rate * Fr ≦ 32 kbps 
                 Rate * Fr ≦ 32 kbps 
               
               
                   
                 Rate/Previous DRC * Fr ≦ 
                 &amp; CINR ≦ 3 dB 
                 &amp; CINR ≦ 3 dB 
               
               
                   
                 32 kbps 
               
               
                 Interval for Judgment 
                 500 ms 
                 500 ms 
                 500 ms 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 12 
               
               
                   
                   
               
               
                   
                 Radio Communication Network 100 
                 Radio Communication Network 200 
                 Radio Communication Network 300 
               
               
                   
                 (e.g. CDMA 1x EV-DO) 
                 (e.g. IEEE 802.16e) 
                 (e.g. WLAN) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Radio Parameter for 
                 RSSI, Tx_Power 
                 RSSI, Tx_Power 
                 RSSI 
               
               
                 QoS Related Threshold 7 (200 ms) 
               
               
                 Logical Equation for Judgment 
                 RSSI ≦ −80 dBm 
                 RSSI ≦ −80 dBm 
                 RSSI ≦ −80 dBm 
               
               
                   
                 &amp; Tx_Power ≧ 15 dBm 
                 &amp; Tx_Power ≧ 15 dBm 
               
               
                 Interval for Judgment 
                 500 ms 
                 500 ms 
                 500 ms 
               
               
                 Radio Parameter for 
                 RSSI, Tx_Power 
                 RSSI, Tx_Power 
                 RSSI 
               
               
                 QoS Related Threshold 8 (300 ms) 
               
               
                 Logical Equation for Judgment 
                 RSSI ≦ −90 dBm 
                 RSSI ≦ −85 dBm 
                 RSSI ≦ −85 dBm 
               
               
                   
                 &amp; Tx_Power ≧ 18 dBm 
                 &amp; Tx_Power ≧ 18 dBm 
               
               
                 Interval for Judgment 
                 500 ms 
                 500 ms 
                 500 ms 
               
               
                 Radio Parameter for 
                 RSSI, Tx_Power 
                 RSSI, Tx_Power 
                 RSSI 
               
               
                 QoS Related Threshold 9 (400 ns) 
               
               
                 Logical Equation for Judgment 
                 RSSI ≦ −95 dBm 
                 RSSI ≦ −90 dBm 
                 RSSI ≦ −90 dBm 
               
               
                   
                 &amp; Tx_Power ≧ 20 dBm 
                 &amp; Tx_Power ≧ 20 dBm 
               
               
                 Interval for Judgment 
                 500 ms 
                 500 ms 
                 500 ms 
               
               
                   
               
             
          
         
       
     
         [0070]    In Tables 10 to 12, Previous Rate and Previous Data Rate Control (Previous DRC) are an average communication rate and an average DRC among the most recent 500 ms (when Initial is 500 ms) using the current point as the basis. Furthermore, Fr indicates a link header redundancy. Specifically, provided that an IP packet length transmitted to the radio link controllers  12 A to  12 C is Lip, a header length added in the radio link controllers  12 A to  12 C is HLlnk and a communication rate measured by the radio link controllers  12 A to  12 C is Rlnk, the communication rate Rip of the IP layer is calculated by Formula 1. 
         [0000]        Fr= Lip/(Lip+HLlnk) 
         [0000]      Rip=Rlnk*  Fr    (Formula 1) 
         [0071]    The specifying of a single QoS parameter for the MIH function unit  13  is conventionally defined in IEEE802.21. However, in this embodiment, multiple QoS parameters, the service quality requirement values of the QoS parameters (QoS_Related_Threshold) and logical equations for judgment (logical equations to judge listed parameters) associated with the service quality requirement values are associated with one another in the MIH function unit  13 . 
         [0072]    Specifically, InitiateAction Threshold and ExecuteAction Threshold are not involved at all with the service quality requirement values specified by the mobility manager  14  and the higher layer entity  15  (MIH user). InitiateAction Threshold and ExecuteAction Threshold are thresholds defined in consideration of the communication quality in the link layer (L 2 ). 
         [0073]    On the other hand, QoS_Related_Threshold is a threshold that has been mapped by the MIH function unit  13  onto the communication quality in the link layer (L 2 ) for the service quality requirement value specified by the mobility manger  14  or the higher layer entity  15 . For example, a bandwidth (communication rate) is specified as the service quality requirement value specified by the mobility manager  14  or the higher layer entity  16 . Then, the communication quality thresholds (RSSI or CINR, for example) of the multiple link layers (L 2 ) corresponding to the aforementioned bandwidth are mapped as QoS_Related_Threshold or logical equation to judge listed parameters. 
         [0074]    In step S 111 , the radio link controller  12 A transmits Link_Configure_Threshold. confirm to the MIH function unit  13 . Link_configure_Threshold. confirm specifically indicates that the radio link controller  12 A has normally received Link_Configure_Threshold. request. 
         [0075]    In step S 113 , the MIH function unit  13  transmits MIH_Configure_Link_confirm to the mobility manager  14  upon receipt of Link_Configure_Threshold. confirm. MIH_Configure_Link_confirm specifically indicates that the MIH function unit  13  has normally received MIH_Configure_Link. request. In addition, in step S 115 , MIH function unit  13  transmits MIH_QoS_Threshold. confirm to the mobility manager  14 . MIH_QoS_Threshold. confirm specifically indicates that the MIH function unit  13  has normally received MIH_QoS_Threshold. request. 
         [0076]    In step S 117 , the radio link controller  12 A detects that the communication quality of the radio link RL connected to the radio communication network  100  (1xEV-DO) has reached InitiateAction Threshold. 
         [0077]    In step S 119 , the radio link controller  12 A notifies the MIH function unit  13  that the communication quality of the radio link RL has reached InitiateAction Threshold. Specifically, the radio link controller  12 A transmits Link_Parameters_Report indication to the MIH function unit  13 . 
         [0078]      FIG. 8  shows a format of Link_Parameters-_Report. indication. Table 13 shows the content of each parameter included in Link_Parameters_Report. indication. 
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 13 
               
               
                   
               
               
                   
                   
                 Valid 
                   
               
               
                 Name 
                 Type 
                 Range 
                 Description 
               
               
                   
               
             
             
               
                 Parameter Type 
                 INTEGER 
                 N/A 
                 Parameter for which threshold has 
               
               
                   
                   
                   
                 been crossed, 
               
               
                 old Value of Link Parameter 
                 Threshold values are dependent on 
                 N/A 
                 Old parameter value 
               
               
                   
                 parameter for which they are being 
               
               
                   
                 set. 
               
               
                 new Value Of Link Parameter 
                 Threshold values are dependent on 
                 N/A 
                 New parameter value 
               
               
                   
                 parameter for which they are being 
               
               
                   
                 set. 
               
               
                 Kind of action 
                 INTEGER 
                 N/A 
                 1: Initiate Action 
               
               
                   
                   
                   
                 2: Execute Action. 
               
               
                   
                   
                   
                 3. QoS_Action1 
               
               
                   
                   
                   
                 * 
               
               
                   
                   
                   
                 * 
               
               
                   
                   
                   
                 * 
               
               
                   
                   
                   
                 * 
               
               
                   
                   
                   
                 N + 2: QoS_Action N 
               
               
                 Logical equation to 
                 Logical equation 
                 N/A 
                 Logical equation for QoS judgment 
               
               
                 judge listed parameters 
               
               
                   
               
             
          
         
       
     
         [0079]    In step S 121 , the MIH function unit  13  transmits MIH_Link_Parameters_Report. indication to the mobility manager  14  upon receipt of Link_Parameters Report. indication. 
         [0080]      FIG. 9  shows a format of MIH_Link_Parameters_Report indication. In addition, Tables 14 and 15 show the content of s each parameter included in MIH_Link_Parameters_Report. indication. 
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 14 
               
               
                   
               
               
                 Name 
                 Type 
                 Valid range 
                 Description 
               
               
                   
               
             
             
               
                 Source Identifier 
                 MIHF ID 
                 N/A 
                 This identifies the invoker of this primitive which can be 
               
               
                   
                   
                   
                 either local MIHF or a remote MIHF. 
               
               
                 Destination Identifier 
                 MIH User ID 
                 N/A 
                 This identifies the final receiver of this primitive among MIH 
               
               
                   
                   
                   
                 Users. 
               
               
                 Link Identifier 
                 LINK ID 
                 N/A 
                 Identifier of the link associated with the event. 
               
               
                 Link Parameters Status 
                 LIST 
                 N/A 
                 A list of Link Parameters Status, as defined in Table 38-2. 
               
               
                 List 
               
               
                 QoS Parameters Status 
                 LIST 
                   
                 A list of QoS Parameters Status, as defined In Table 
               
               
                 List 
                   
                   
                 38-2. 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
               
               
             
           
               
                 TABLE 15 
               
             
             
               
                   
               
               
                 Table 38-2 Elements of link parameters status 
               
             
          
           
               
                   
                   
                 Valid 
                   
               
               
                 Name 
                 Type 
                 range 
                 Description 
               
               
                   
               
               
                 Parameter Type 
                 INTEGER 
                 0-255 
                 Parameter being reported, as defined in Table 12 
               
               
                 Current Value 
                 Values dependent on 
                 N/A 
                 The current value of the parameter. 
               
               
                   
                 Parameter Type 
               
               
                 Threshold Crossed 
                 ENUMERATED 
                 0-2  
                 Provided when this is a threshold-crossing event. 
               
               
                 for Link Parameter 
                   
                   
                 0: Initiate Action Threshold crossed. 
               
               
                   
                   
                   
                 1: Execute Action Threshold crossed 
               
               
                 Threshold 
                 ENUMERATED 
                 0-255 
                 Provided when this is a threshold-crossing event. 
               
               
                 Crossed for QoS 
                   
                   
                 0: reserved 
               
               
                 Parameter 
                   
                   
                 11: Threshold 1 for QoS parameter 1 
               
               
                   
                   
                   
                 * 
               
               
                   
                   
                   
                 * 
               
               
                   
                   
                   
                 n1: Threshold n for QoS parameter 1 
               
               
                   
                   
                   
                 1m: Threshold 1 for QoS parameter m 
               
               
                   
                   
                   
                 * 
               
               
                   
                   
                   
                 * 
               
               
                   
                   
                   
                 nm: Threshold n for QoS parameter m 
               
               
                   
               
             
          
         
       
     
         [0081]    In step S 123 , the mobility manager  14  transmits MIH_Link_Up. request to the MIH function unit  13 . MIH_Link_Up. request specifically requests a connection to the radio communication network  200  (WiMAX) of the handover destination in order to start preparation for the handover. Note that MIH_Link_Up. request is not defined in IEEE802.21, but a newly defined command. 
         [0082]    In step S 125 , the MIH function unit  13  instructs the radio link controller  12 B on the connection to the radio communication network  200 . Specifically, the MIH function unit  13  transmits Link_Up. request to the radio link controller  12 B. 
         [0083]    In step S 127 , the radio link controller  12 B sets the radio link RL for the radio communication network  200 . 
         [0084]    In step S 129 , the radio link controller  12 B transmits Link_Up. indication to the MIH function unit  13  upon completion of the setting of the radio link RL for the radio communication network  200 . 
         [0085]    In step S 131 , the MIH function unit  13  notifies the mobility manager  14  that the setting of the radio link RL for the radio communication network  200  is completed, upon receipt of Link_Up. indication. Specifically, the MIH function unit  13  transmits MIH_Link_Up. indication to the mobility manager  14 . Note that MIH_Link_Up. indication is not defined in IEEE802.21, but a newly defined notification. 
         [0086]    In step S 133 , the radio link controller  12 A detects that the communication quality of the radio link RL connected to the radio communication network  100  (1xEV-DO) has reached ExecuteAction Threshold. 
         [0087]    In step S 135 , the radio link controller  12 A notifies the MIH function unit  13  that the communication quality of the radio link RL has reached InitiateAction Threshold. Specifically, the radio link controller  12 A transmits Link_Parameters_Report. indication to the MIH function unit  13 . 
         [0088]    In step  137 , the MIH function unit  13  transmits MIH_Link_Parameters_Report. indication to the mobility manager  14  upon receipt of Link_Parameters_Report. indication. 
         [0089]    In step  139 , the mobility manager  14  transmits MIH_Switch. request to the MIH function unit  13  in order to start a handover to the radio communication network  200 . 
         [0090]    In step S 141 , the MIH function unit  13  transmits MIR_Switch. confirm to the mobility manager  14 . MIH_Switch. confirm specifically indicates that the MIH function unit  13  has normally received MIH_Switch. request. 
         [0091]    In step S 143 , the MIH function unit  13  and the radio link controller  12 B execute the handover from the radio communication network  100  to the radio communication network  200 , that is, the switching from the radio communication network  100  to the radio communication network  200 . 
         [0092]    In step S 145 , the MIH function unit  13  transmits MIH.Switch.report to the mobility manager  14 . MIH.Switch.report specifically indicates that the switching to the radio communication network  200  is completed. 
         [0093]    In step S 147 , the mobility manager  14  transmits MIH _Link_Down. request to the MIH function unit  13  upon receipt of MIH.Switch.report. MIH_Link_Down. request specifically requests a disconnection of the radio link RL set for the radio commLunication network  100  from the radio communication network  100 . Note that MIH_Link_Down. request is not defined in IEEE802.21, but a newly defined command. 
         [0094]    In step S 149 , the MIH function unit  13  transmits Link_Down. request to the radio link controller  12 A in order to disconnect the radio link RL set for the radio communication network  100  from the radio communication network  100 . 
         [0095]    In step S 151 , the radio link controller  12 A disconnects the radio link RL set for the radio communication network  100  from the radio communication network  100 . 
         [0096]    In step S 153 , the radio link controller  12 A transmits Link_Down, indication to the MIH function unit  13  in response to the fact that the radio link controller  12 A has disconnected the radio link RL set for the radio communication network  100  from the radio communication network  100 . 
         [0097]    In step S 155 , upon receipt of Link_Down. indication, the MIH function unit  13  notifies the mobility manager  14  that the radio link controller  12 A has disconnected the radio link RL set for the radio communication network  100  from the radio communication network  100 . Specifically, the MIH function unit  13  transmits MIH_Link_Down. indication to the mobility manager  14 . 
       (3.2) Operation Example 2  
       [0098]    In Operation Example 1 described above, the preparation for a handover is started when the condition that the communication quality of the radio link RL has reached InitiateAction Threshold (refer to step S 117 ) is satisfied. Then, the handover is started when the condition that the communication quality thereof has reached ExecuteAction Threshold (step S 133 ) is satisfied. In Operation Example 2, instead of InitiateAction Threshold and ExecuteAction Threshold, the handover is executed on the basis of multiple thresholds (QoS_Related_Threshold  1  to  9 ) associated with the service quality requirement values. 
         [0099]    Specifically, as shown in Tables 7 to 9 and Tables 10 to 12, nine thresholds, which are QoS_Related_Threshold  1  to  9  (P=Current DRC*Previous Rate/Previous DRC*Fr≦16 kbps shown in Table 11, for example), can be set in this embodiment. QoS_Related_Threshold  1  to  9  can be associated with predetermined service quality requirement values (Bandwidth: 8 kbps, for example), respectively. 
         [0100]      FIG. 4  is an internal sequence diagram when the radio communication terminal  10  executes a handover from the radio communication network  100  to the radio communication network  200  on the basis of QoS_Related_Threshold. Note that a description below will be mainly given of a portion different from that of Operation Example 1 shown in  FIG. 3 . 
         [0101]    The processing in steps S 201 , S 203  . . . S 215  is substantially the same as that of steps S 101 , S 103 , . . . S 115  shown in  FIG. 3 . However, in step S 201 , an assumption is made that the higher layer entity  15  requests Bandwidth: 8 kbps as a service quality requirement value. In addition, in step S 207 , the MIH function unit  13  transmits a logical equation for judgment to the radio link controller  12 A along with QoS_Related_Threshold  1  to  9 . The logical equation for judgment is specifically used to determine whether or not the communication quality of the radio link RL has reached QoS_Related_Threshold  1  to  9 . 
         [0102]    Specifically, the MIH function unit  13  performs mapping of the logical equations for judgment onto each service quality requirement value in accordance with the contents of Tables 10 to 12 on the basis of the QoS parameter and policy information in the higher layer entity  15 . In addition, the MIH function unit  13  transmits combinations of the mapped service quality requirement values and the logical equations for judgment to the radio link controller  12 A. 
         [0103]    In step S 217 , the radio link controller  12 A detects that the communication quality of the radio link RL connected to the radio communication network  100  (1xEV-DO) has reached QoS_Related_Threshold  4 . 
         [0104]    Specifically, the radio link controller  12 A determines that the communication quality at the radio link RL has reached QoS_Related_Threshold  4  when the DRC value (unit: bps) in the radio link RL satisfies the logical equations for judgment P=Current DRC*Previous Rate/Previous DRC*Fr≦16 kbps (refer to Table 11). 
         [0105]    In step S 219 , the radio link controller  12 A notifies the MIH function unit  13  that the communication quality of the radio link  RL has reached QoS_Related_Threshold  4 . specifically, the radio link controller  12 A transmits Link_Parameters_Report , indication to the MIH function unit  13 . As shown in  FIG. 8  and Table 13, the definition of Link_Parameters_Report. indication is extended (QoS_Action  1  to N) in this embodiment, so as to explicitly show one of QoS_Related_Threshold  1  to  9 . 
         [0106]    In step S 221 , the MIH function unit  13  transmits MIH_Link_Parameters_Report. indication to the mobility manager  14  upon receipt of Link_Parameters_Report. indication. Specifically, as shown in  FIG. 9  and Tables 14 to 15, the definition of MIH_Link_Parameters_Report. indication is extended in this embodiment so that QoS Parameters Status List can be added and the type of QoS parameter and satisfied condition can be notified. 
         [0107]    The processing of steps S 223 , S 225 , S 227 , and S 229  is substantially the same as the processing of steps S 123 , S 125 , S 127 , and S 129  shown in  FIG. 3 . 
         [0108]    In step S 230 , the mobility manager  14  executes adjustment of setting contents of the higher layer entity  15 , that is, adjustment of parameters of an IP application (IP phone application, for example) currently being executed in the higher layer entity  15 . 
         [0109]    In this embodiment, the mobility manager  14  requests the higher layer entity  15  to execute changing of encoding rate of the codec, playback speed of decoded audio information, jitter buffer capacity or the like in order to correspond the setting to the radio environment (communication rate) specified by QoS_Related_Threshold  4 . The higher layer entity  15  changes QoS parameters on the basis of the request from the mobility manager  14 . For example, if the higher layer entity  15  is TCP, the higher layer entity  15  changes the congestion window size. Alternatively, to if the higher layer entity  15  is an IP phone application, the higher layer entity  15  changes the encoding rate of the codec. 
         [0110]    The processing of step S 231  is the same as the processing of step S 131  shown in  FIG. 3 . In step S 233 , the radio link controller  12 A detects that the communication quality of the radio link RL connected to the radio communication network  100  (1xEV-DO) has reached QoS_Related_Threshold  2 . 
         [0111]    Specifically, the radio link controller  12 A determines that the communication quality of the radio link RL has reached QoS_Related_Threshold  2  when the DRC value (unit: bps) in the radio link RL satisfies the logical equations for judgment P=Current DRC*Previous Rate/Previous DRC*Fr≦8 kbps (refers to Table 10). 
         [0112]    In step S 235 , the radio link controller  12 A notifies the MIH function unit  13  that the communication quality of the radio link RL has reached QoS_Related_Threshold  2 . Note that the processing content in this case is the same as that of step S 219 . 
         [0113]    In step S 237 , the MIH function unit  13  transmits MIH_Link_Parameters_Report. indication to the mobility manager  14 . Note that the processing content in this case is the same as that of step S 221 . 
         [0114]    In step S 239 , the mobility manager  14  transmits MIH_Switch request to the MIH function unit  13  in order to start a handover to the radio communication network  200 . Specifically, the mobility manager  14  determines to execute the handover to the radio communication network  200  in response to the fact that the communication quality of the radio link RL has reached the service quality requirement value (Bandwidth: 8 kbps) corresponding to QoS_Related_Threshold  2 . Note that in step S 239 , the mobility manager  14  may execute adjustment of parameters of an IP application currently being executed in the higher layer entity  15 , as in the case of step S 230 . 
         [0115]    The processing in steps S 241 , S 243 , . . . S 255  are substantially the same as the processing of steps S 141 , . . . S 155  as shown in  FIG. 3 . 
       (3.3) Modification Example 
       [0116]    Although the communication quality threshold (InitiateAction Threshold, ExecuteAction Threshold or QoS_Related_Threshold) is determined on the basis of QoS parameters in Operation Examples 1 and 2 described above, the MIH function unit  13  may determine the communication quality threshold on the basis of policy information. 
         [0117]    Table 16 shows radio parameters, communication quality thresholds (InitiateAction Threshold, ExecuteAction Threshold) and logical equations for judgment, of each of the radio communication networks, based on the communication path (communication medium) selection policy when an IP phone application is executed. 
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 16 
               
               
                   
                   
               
               
                   
                 Radio Communication Network 100 
                 Radio Communication Network 200 
                 Radio Communication 
               
               
                   
                 (e.g. CDMA 1x EV-DO) 
                 (e.g. IEEE 802.16e) 
                 Network 300 (e.g. WLAN) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Radio Parameter 
                 {SINR, RSSI, DRC, Tx_Power, 
                 {SINR, RSSI} 
                 {CIR, RSSI} 
               
               
                   
                 DRC_Lock} 
               
               
                 Threshold 
                 {+2 dB, −70 dBm, 7, 10 dBm, 0.8} 
                 {3 dB, −70 dBm} 
                 {3 dB, −75 dBm} 
               
               
                 (Initiate Action) 
               
               
                 Threshold 
                 {−3 dB, −75 dBm, 5, 15 dBm, 0.9} 
                 {−2 dB, −75 dBm} 
                 {0 dB, −80 dBm} 
               
               
                 (Execute Action) 
               
               
                 Logical Judgment Equation 
                 (SINR &amp; RSSI &amp; DRC)|| 
                 (SINR &amp; RSSI) 
                 (CIR &amp; RSSI) 
               
               
                 (Initiate Action) 
                 (Tx_Power &amp; DRC_Lock) 
               
               
                 Logical Judgment Equation 
                 (SINR &amp; RSSI &amp; DRC)|| 
                 (SINR &amp; RSSI) 
                 (CIR &amp; RSSI) 
               
               
                 (Execute Action) 
                 (Tx_Power &amp; DRC_Lock) 
               
               
                   
               
             
          
         
       
     
         [0118]    As shown in Table 16, the radio parameters, communication quality thresholds and logical equations for judgment are different depending on the types of radio communication networks even with the same communication path policy. Accordingly, the MIH function unit  13  needs to have such a table for each policy. 
         [0119]    Table 17 shows radio parameters, communication quality thresholds (InitiateAction Threshold, ExecuteAction Threshold) and logical equations for judgment of each of the radio communication networks based on the communication path (communication medium) selection policy when a streaming distribution application is executed. 
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 17 
               
               
                   
                   
               
               
                   
                 Radio Communication Network 100 
                 Radio Communication Network 200 
                 Radio Communication Network 300 
               
               
                   
                 (e.g. CDMA 1x EV-DO) 
                 (e.g. IEEE 802.16e) 
                 (e.g. WLAN) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Radio Parameter 
                 {SINR, RSSI, DRC, Tx_Power, 
                 {SINR, RSSI, Successful ratio of 
                 {CIR, RSSI, PER, Rate} 
               
               
                   
                 DRC_Lock} 
                 DL-MAP receive, Rate, 
               
               
                   
                   
                 Modulation class, Tx_Power} 
               
               
                 Threshold 
                 {0 dB, −80 dBm, 6, 15 dBm, 0.8} 
                 {3 dB, −70 dBm, 0.9, 500 kbps, QPSK 
                 {3 dB, −75 dBm, 0.1, 500 kbps} 
               
               
                 (Initiate Action) 
                   
                 ¾, 15 dBm} 
               
               
                 Threshold 
                 {−5 dB, −90 dBm, 4, 23 dBm, 0.8} 
                 {−2 dB, −80 dBm, 0.8, 200 kbps, QPSK 
                 {0 dB, −85 dBm, 0.1, 500 kbps} 
               
               
                 (Execute Action) 
                   
                 ½, 23 dBm) 
               
               
                 Logical Judgment Equation 
                 (SINR &amp; RSSI &amp; DRC)|| 
                 (SINR &amp; RSSI &amp; Successful ratio 
                 (CIR &amp; PER)|RSSI 
               
               
                 (Initiate Action) 
                 (Tx_Power &amp; DRC_Lock) 
                 of DL-MAP receive)||Tx_Power 
               
               
                 Logical Judgment Equation 
                 (SINR &amp; RSSI &amp; DRC)|| 
                 (SINR &amp; RSSI &amp; Successful ratio 
                 (CIR &amp; PER)|RSSI 
               
               
                 (Execute Action) 
                 (Tx_Power &amp; DRC_Lock) 
                 of DL-MAP receive)||Tx_Power 
               
               
                   
               
             
          
         
       
     
         [0120]    In addition, Table 18 shows radio parameters, communication quality thresholds (InitiateAction Threshold, ExecuteAction Threshold) and logical equations for judgment of each of the radio communication networks based on the communication path (communication medium) selection policy when priority for the selection of the radio communication network is set as to satisfy: radio communication network  300 &gt;radio communication network  200 &gt;radio communication network  100 . 
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 18 
               
               
                   
                   
               
               
                   
                 Radio Communication Network 100 
                 Radio Communication Network 200 
                 Radio Communication Network 300 
               
               
                   
                 (e.g. CDMA 1x EV-DO) 
                 (e.g. IEEE 802.16e) 
                 (e.g. WLAN) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Radio Parameter 
                 {SINR, RSSI, DRC} 
                 {SINR, RSSI, Rate, 
                 {CIR, RSSI, PER, Rate} 
               
               
                   
                   
                 Modulation class} 
               
               
                 Threshold 
                 {+1 dB, −70 dBm, 7} 
                 {3 dB, −70 dBm, 700 kbps, 16QAM 
                 {3 dB, −70 dBm, 0.05, 700 kbps} 
               
               
                 (Initiate Action) 
                   
                 ½} 
               
               
                 Threshold 
                 {−3 dB, −80 dBm, 5} 
                 {−2 dB, −75 dBm, 400 kbps, QPSK 
                 {0 dB, −75 dBm, 0.1, 400 kbps} 
               
               
                 (Execute Action) 
                   
                 ¾} 
               
               
                 Logical Judgment Equation 
                 (SINR &amp; RSSI &amp; DRC)| 
                 (SINR &amp; RSSI &amp; Rate) 
                 (CIR &amp; PER &amp; RSSI) 
               
               
                 (Initiate Action) 
               
               
                 Logical Judgment Equation 
                 (SINR &amp; RSSI &amp; DRC) 
                 (SINR &amp; RSSI &amp; Rate) 
                 (CIR &amp; PER &amp; RSSI 
               
               
                 (Execute Action) 
               
               
                   
               
             
          
         
       
     
       (4) Effects And Advantages 
       [0121]    According to the radio communication terminal  10 , when the MIH function unit  13  is notified by the radio link controllers  12 A to  12 C that the communication quality of the radio link RL being respectively set thereto has reached the communication quality threshold, the MIR function unit  13  then notifies the mobility manager  14  that the communication quality of the radio link RL has reached the service quality requirement value corresponding to the communication quality threshold. 
         [0122]    Accordingly, the mobility manager  14  can promptly determine whether or not to change the service quality requirement value in the mobility manager  14  or the service quality requirement value for the higher layer entity  15 , or to execute a handover when being notified by the MIH function unit  13  that the communication quality of the radio link RL has reached the service quality requirement value. 
         [0123]    In other words, since the MIH function unit  13  associates communication quality thresholds with service quality requirement values, the mobility manager  14  does not have to recognize the relationships between each of the communication quality thresholds and each of the service quality requirement values, which are dependent on the characteristics of the radio communication networks  100 ,  200  and  300 . The mobility manager  14  can thus execute processing such as a handover appropriate for the communication quality of the radio link RL on the basis of the service quality requirement values. Furthermore, since the mobility manager  14  does not have to recognize the relationships between each of the communication quality thresholds and each of the service quality requirement value, which are dependent on the characteristics of the radio communication networks  100 ,  200  and  300 , it is possible to suppress the development costs of the mobility manager  14 . 
         [0124]    In this embodiment, the mobility manager  14  executes a handover to another radio communication network, or changes the setting contents of an application currently being executed in the higher layer entity  15  when being notified by the MIH function unit  13  that the communication quality of the radio link RL has reached the service quality requirement value corresponding to the communication quality threshold. The mobility manger  14  can thus select processing (execution of the handover or changing of so the setting contents of the application) appropriate for the condition of the radio link RL or the type of the application currently being executed in the higher layer entity  15 . 
       (5) Other Embodiments 
       [0125]    As described above, the content of the present invention has been disclosed through one embodiment of the present invention. However, the descriptions and the drawings constituting a part of the disclosure should not be construed to limit the present invention. Various alternative embodiments should be obvious to so those skilled in the art from this disclosure. 
         [0126]    For example, the nine types of QoS_Related_Threshold (QoS_Related_Threshold  1  to  9 ) are provided in the aforementioned embodiment. However, the number of types of QoS_Related_Threshold may be less than nine. Alternatively, the number of types of QoS_Related_Threshold may be more than nine. 
         [0127]    Although a required bandwidth (communication rate) is used as a service quality requirement value in the aforementioned embodiment, the QoS parameter to be used as the service quality requirement value is not limited to the required bandwidth. 
         [0128]    As described, obviously, the present invention includes various embodiments not described herein. The technical scope of the present invention is thus defined only by invention identifying matters according to the scope of claims appropriate to the descriptions above.