This application claims benefit of priority under 35USC§119 to Japanese Patent Application No. 2003-338350, filed on Sep. 29, 2003, the entire contents of which are incorporated by reference herein.
1. Field of the Invention
The present invention relates to a wireless communication apparatus having a plurality of wireless schemes to conduct wireless communication with respectively different wireless schemes.
2. Related Art
A wireless communication apparatus having a plurality of wireless communication systems has been proposed (see FIG. 8 in Japanese Patent Application Laid-Open Publication No. 2001-197538 and see FIG. 10 in Japanese Patent Application Laid-Open Publication No. 2002-112347). A wireless communication apparatus disclosed in Japanese Patent Application Laid-Open Publication No. 2001-197538 selects one of wireless communication systems in accordance with a table in which a plurality of wireless communication systems are provided with a priority order and classified. Conventional wireless communication systems disclosed in Japanese Patent Application Laid-Open Publication No. 2001-197538 and 2002-112347 select a communication path by giving priority to a specific parameter, such as a communication cost.
Conventionally, a wireless communication system is selected in accordance with a specific parameter. Therefore, it is not possible to select an optimum wireless communication system while taking a plurality of parameters into consideration.
Furthermore, conventionally, a plurality of wireless communication systems are uniquely provided with a priority order. Even if there is a wireless communication system that is low in priority order, but that is capable of maintaining a sufficient communication quality, therefore, a wireless communication system having high priority is selected unconditionally. This results in a problem that a large number of unnecessary handovers occur.
The present invention has been achieved in order to solve the problems. An object of the present invention is to provide a wireless communication apparatus and a wireless communication method capable of precisely selecting one of a plurality of wireless schemes in accordance with a parameter.
In order to solve the above-described problem, an object of the present invention is to provide
A wireless communication apparatus according to one embodiment of the present invention, comprising:
Furthermore, a wireless communication method according to one embodiment of the present invention, comprising:
Hereafter, embodiments of the present invention will be described with reference to the drawings.
The analog unit 1 includes antennas 5a, 5b and 5c, power amplifiers 6a, 6b and 6c, and frequency conversion units 7a, 7b and 7c in association with a plurality of wireless communication systems, respectively.
A digital unit 2 includes a digital signal processing unit 11, an application unit 12, a system selection control unit 13, and a memory 14. A user interface unit 15 is connected to the system selection control unit 13.
Operation of the wireless communication apparatus shown in
If the wireless communication system selected by the system selection control unit 13 is the wireless communication system 8b, then the antenna 5b, the power amplifier 6b and the frequency conversion unit 7b in the analog unit 1 are selected.
If signal is received in this state, then received signal input to the antenna 5b is amplified by the power amplifier 6b, converted to a baseband signal in the frequency conversion unit 7b, and then input to the A/D & D/A converter 3. After the received signal is converted from an analog signal to a digital signal in the A/D & D/A converter 3, decoding processing associated with encoding processing of the wireless communication system 8 selected by the digital signal processing unit 11 is conducted. The decoded data is input to the application unit 12, subjected to processing associated with application, then input to the user interface unit 15, and transferred to the user.
Data in the wireless communication system 8 with an error detection code such as a CRC code added thereto is subjected to decoding processing in the digital signal processing unit 11, and then subjected to error detection processing in the digital signal processing unit 11. An error detection result is sent to the system selection control unit 13. The system selection control unit 13 manages the error detection result sent from the digital signal processing unit 11, and determines whether handover to another system is necessary.
On the other hand, when transmitting data, a user's request input at the user interface unit 15 is input to the application unit 12, data is subjected to processing associated with application, then input to the digital signal processing unit 11, and subjected to encoding processing associated with the selected wireless communication system 8b. The data encoded in the digital signal processing unit 11 is input to the A/D & D/A converter 3, converted to an analog signal, then subjected to frequency conversion to an RF frequency in the frequency conversion unit 7b, and output from the antenna 5b.
The wireless communication systems 8 are classified into classes according to their respective priorities. A wireless communication system 8 having the highest priority is classified into class 1. A wireless communication system 8 having the second highest priority is classified into class 2. A wireless communication system having the lowest priority is classified into class 3.
If the criterion of the class 1 is not satisfied, then it is determined on the basis of priority whether a criterion of the class 2 is satisfied (step S3). If the criterion of the class 2 is satisfied, then the wireless communication system 8 is classified into the class 2 (step S4).
If the criterion of the class 2 is not satisfied, then it is determined whether a criterion of the class 3 is satisfied (step S5). If the criterion of the class 3 is satisfied, then the wireless communication system 8 is classified into the class 3 (step S6).
If a wireless communication system belonging to the class 1 is not present, then it is determined whether a wireless communication system belonging to the class 2 is present (step S13). If one or more wireless communication systems 8 belonging to the class 2 are present, then one is selected from among the wireless communication systems 8 belonging to the class 2 (step S14).
If a wireless communication system belonging to the class 2 is not present, then it is determined whether a wireless communication system belonging to the class 3 is present (step S15). If one or more wireless communication systems belonging to the class 3 are present, then one is selected from among the wireless communication systems 8 belonging to the class 3 (step S16).
With reference to
Thus, in the first embodiment, a plurality of wireless communication systems 8 are provided with a priority order in accordance with a parameter and classified into a plurality of classes, and one wireless communication system 8 is selected from among wireless communication systems 8 that belong to the class 1 having the highest priority. Therefore, a wireless communication system 8 suitable for the parameter can be selected.
In the second embodiment, a plurality of wireless communication systems 8 are classified into a plurality of classes for every two parameters.
A wireless communication apparatus of the second embodiment has a configuration similar to that shown in
If classification is conducted on the basis of the parameter 1, wireless communication systems 8b and 8c are classified into class 1 having the highest priority, a wireless communication system 8a is classified into class 2 having the second highest priority, and wireless communication systems 8c and 8d are classified into class 3 having the lowest priority as shown in
In selecting a wireless communication system 8 to be used, first, the wireless communication system 8b and the wireless communication system 8c belonging to the class 1 having the highest priority become candidates for selection according to the classification based on the parameter 1. Subsequently, according to the classification using the parameter 2, the wireless communication system 8b is classified into the class 2 and the wireless communication system 8e is classified into the class 3. Therefore, the wireless communication system 8b, which belongs to the same class 1 as the wireless communication system 8e on the basis of the parameter 1, but belongs to the class 2 having higher priority on the basis of the parameter 2, is selected as the wireless communication system 8 to be used.
In this way, a wireless communication system 8 is selected on the basis of the two parameters 1 and 2. Therefore, an optimum wireless communication system 8 satisfying a plurality of parameters can be selected.
A concrete example of the second embodiment will now be described.
In
Furthermore, in
As for the criterion for this classification, for example, the class 1 corresponds to a wireless communication system having a available channel capacity of approximately 90%. The class 2 corresponds to a wireless communication system having a available channel capacity of 70%. The class 3 corresponds to a wireless communication system having a available channel capacity of 50%. The class 4 corresponds to a wireless communication system having a available channel capacity of 30%. The class 5 corresponds to a wireless communication system having a available channel capacity of 10%. Although the wireless communication systems 8 have been classified into five classes in this example, it is not always necessary that the number of classes is five, but the number of classes may be greater than or less than five.
Subsequently, it is determined whether a wireless communication system 8 belonging to the class 1 classified on the basis of the parameter 2 is present (step S24). If one or more wireless communication systems 8 belonging to the class 1 are present, then one of them is selected (step S25).
If the decision at the step S24 yields a negative result, then it is determined whether a wireless communication system 8 belonging to class 2 classified on the basis of the parameter 2 is present (step S26). If one or more wireless communication systems 8 belonging to the class 2 are present, then one of them is selected (step S27).
If the decision at the step S26 yields a negative result, then it is determined whether a wireless communication system 8 belonging to class 3 classified on the basis of the parameter 2 is present (step S28). If one or more wireless communication systems 8 belonging to the class 3 are present, then one of them is selected (step S29).
If the decision at the step S28 yields a negative result, then it is determined whether a wireless communication system 8 belonging to class 4 classified on the basis of the parameter 2 is present (step S30). If one or more wireless communication systems 8 belonging to the class 4 are present, then one of them is selected (step S31).
If the decision at the step S30 yields a negative result, then it is determined whether a wireless communication system 8 belonging to class 5 classified on the basis of the parameter 2 is present (step S32). If one or more wireless communication systems 8 belonging to the class 5 are present, then one of them is selected (step S33).
On the other hand, if a wireless communication system 8 belonging to class 1 classified on the basis of the parameter 1 is not present at the step S22, then it is determined whether a wireless communication system 8 belonging to the class 2 classified on the basis of the parameter 1 is present (step S34). If a wireless communication systems 8 belonging to the class 2 is present, then the processing of the steps S23 to S33 is conducted.
If a wireless communication system 8 belonging to class 2 classified on the basis of the parameter 1 is not present at the step S34, then it is determined whether a wireless communication system 8 belonging to the class 3 classified on the basis of the parameter 1 is present (step S35). If a wireless communication system 8 belonging to the class 3 is present, then the processing of the steps S23 to S33 is conducted.
Thus, in the second embodiment, a plurality of wireless communication systems 8 are classified into a plurality of classes for every two parameters, and a wireless communication system 8 is selected by taking two parameters into consideration. Therefore, a wireless communication system 8 that most satisfies two parameters can be selected.
In the third embodiment, a plurality of wireless communication systems 8 are classified into a plurality of classes for every three parameters, and these parameters are provided with a priority order.
A wireless communication apparatus of the third embodiment has a configuration similar to that shown in
As shown in
The parameters 1 to 3 are provided with a priority order. The parameter 1 has the highest priority, and the parameter 2 has the second highest priority. The parameter 3 has the lowest priority.
In selecting a wireless communication system 8 to be used, first, classification based on the parameter 1 having the highest priority is conducted, and the wireless communication systems 8a and 8c belonging to the class 1 having the highest priority become candidates for selection.
Subsequently, according to the classification based on the parameter 2 having the second highest priority, both the wireless communication systems 8a and 8c are classified into the class 1. Therefore, the wireless communication system 8 to be used cannot be determined at this stage. According to the classification based on the parameter 3 having the third highest priority, the wireless communication system 8c is classified into the class 2, and the wireless communication system 8a is classified into the class 3. Therefore, the wireless communication system 8c, which belongs to the same class 1 as the wireless communication system 8a on the basis of the parameter 1 having the highest priority and the parameter 2 having the second highest priority, but belongs to the class 2 having higher priority on the basis of the parameter 3 having the third highest priority, is selected as the wireless communication system 8 to be used.
In this way, a wireless communication system 8 is selected on the basis of criteria of the three parameters, i.e., the first parameter having the highest priority, the second parameter having the second highest priority, and the third parameter having the third highest priority. Therefore, an optimum wireless communication system 8 satisfying a plurality of parameters can be selected.
An example in which a wireless communication system 8 is selected on the basis of the classification based on three parameters 1 to 3 provided with a priority order has been described. However, it is not necessary that the number of parameters is always three. A wireless communication system 8 to be used may also be selected on the basis of classification based on the criteria of at least four or at most two parameters provided with a priority order.
Hereafter, a concrete example of the third embodiment will be described.
In
Furthermore, on the basis of the criterion of the service area serving as the parameter having the second highest priority, the wireless communication systems 8a, 8d, 8e and 8h are classified into class 1, the wireless communication systems 8c and 8f are classified into class 2, and the wireless communication systems 8b and 8g are classified into class 3. As for the criterion for this classification, for example, the class 1 corresponds to a wireless communication system having a population cover ratio of service area equal to at least 90%. The class 2 corresponds to a wireless communication system having a population cover ratio of service area equal to at least 70%. The class 3 corresponds to a wireless communication system having a population cover ratio of service area equal to at least 50%. Although the eight wireless communication systems 8 have been classified into three classes in this example, it is not always necessary that the number of classes is three, but the number of classes may be greater than or less than three.
Subsequently, on the basis of the criterion of the communication cost, which is the parameter having the third highest priority, the wireless communication systems 8a and 8b are classified into class 1, and the wireless communication systems 8d, 8e and 8g are classified into class 2. And the wireless communication systems 8c and 8h are classified into class 3, and the wireless communication system 8f is classified into class 4. As for the criterion for this classification, for example, the class 1 corresponds to a wireless communication system having a communication cost per unit quantity equal to approximately 10 yen (or 10 cent). The class 2 corresponds to a wireless communication system having a communication cost per unit quantity equal to approximately 30 yen (or 30 cent). The class 3 corresponds to a wireless communication system having a communication cost per unit quantity equal to approximately 50 yen (or 50 cent). The class 4 corresponds to a wireless communication system having a communication cost per unit quantity equal to approximately 100 yen (or one dollar). Although the eight wireless communication systems 8 have been classified into four classes in this example, it is not always necessary that the number of classes is three, but the number of classes may be greater than or less than four.
Subsequently, on the basis of the criterion of the power dissipation, which is the parameter having the fourth highest priority, the wireless communication systems 8a and 8e are classified into class 1, and the wireless communication systems 8d and 8f are classified into class 2. And the wireless communication systems 8c and 8h are classified into class 3, and the wireless communication system 8b is classified into class 4. The wireless communication system 8g is classified into class 5. As for the criterion for this classification, for example, the class 1 corresponds to a wireless communication system having power dissipation equivalent to continuous use time of approximately 10 hours. The class 2 corresponds to a wireless communication system having power dissipation equivalent to continuous use time of approximately 5 hours. The class 3 corresponds to a wireless communication system having power dissipation equivalent to continuous use time of approximately 3 hours. The class 4 corresponds to a wireless communication system having power dissipation equivalent to continuous use time of approximately 2 hours. The class 5 corresponds to a wireless communication system having power dissipation equivalent to continuous use time of approximately 1 hour. Although the eight wireless communication systems 8 have been classified into five classes in this example, it is not always necessary that the number of classes is five, but the number of classes may be greater than or less than five.
On the other hand, if the decision at the step S48 yields a negative result, then it is determined whether a wireless communication system 8 belonging to class 2 classified on the basis of the parameter 4 is present (step S50). If one or more such wireless communication systems 8 are present, then one is selected from the wireless communication systems 8 belonging to the class 2 (step S51).
On the other hand, if the decision at the step S50 yields a negative result, then it is determined whether a wireless communication system 8 belonging to class 3 classified on the basis of the parameter 4 is present (step S52). If one or more such wireless communication systems 8 are present, then one is selected from the wireless communication systems 8 belonging to the class 3 (step S53).
On the other hand, if the decision at the step S52 yields a negative result, then it is determined whether a wireless communication system 8 belonging to class 4 classified on the basis of the parameter 4 is present (step S54). If one or more such wireless communication systems 8 are present, then one is selected from the wireless communication systems 8 belonging to the class 4 (step S55).
On the other hand, if a wireless communication system 8 belonging to the class 4 classified on the basis of the parameter 4 is not present at the step S54, then it is determined whether a wireless communication system 8 belonging to the class 5 classified on the basis of the parameter 4 is present (step S56). If one or more such wireless communication systems 8 are present, then one is selected from the wireless communication systems 8 belonging to the class 5 (step S57).
The above-described processings of the steps S47 to S57 are also conducted in order when the decision at the step S58, S59 or S60 yields an affirmative result. Furthermore, the above-described processing of the steps S45 to S57 is also conducted when the decision at the step S61 or S62 yields an affirmative result. Furthermore, the above-described processings of the steps 543 to S57 are also conducted when the decision at the step S63 or S64 yields an affirmative result.
In selecting a wireless communication system 8 to be used, first in the processing shown in
Subsequently, according to the classification based on the communication cost, which is the parameter having the third highest priority, the wireless communication systems 8d and 8e are classified into the class 2, and the wireless communication system 8h is classified into the class 3. Therefore, the wireless communication systems 8d and 8e, which belong to the same class 1 as the wireless communication system 8h on the basis of the parameter of the service area having the second highest priority, but belongs to the class 2 having a higher priority classified on the basis of the parameter of the communication cost having the third highest priority, remain as the candidates for selection.
And, according to the classification based on the power dissipation, which is the parameter having the fourth highest priority, the wireless communication system 8e is classified into the class 1, and the wireless communication system 8d is classified into the class 2. Therefore, the wireless communication system 8e, which belongs to the same class 2 as the wireless communication system 8d on the basis of the parameter of the communication cost having the third highest priority, but belongs to the class 1 having the highest priority classified on the basis of the parameter of the power dissipation having the fourth highest priority, is selected as the wireless communication system 8 to be used.
Thus, in the third embodiment, a wireless communication system 8 can be selected by taking the parameters 1 to 4 provided with a priority order into consideration. Therefore, an optimum wireless communication system 8 satisfying a plurality of connection conditions can be selected.
An example in which a wireless communication system 8 to be used is selected on the basis of the classification based on the criteria of four parameters, i.e., the QoS, service area, communication cost and power dissipation which are provided with a priority order has been described. However, it is not necessary that the number of parameters is always four. A wireless communication system 8 to be used may also be selected on the basis of classification based on the criteria of at least five or at most three parameters provided with a priority order.
In the fourth embodiment, a plurality of wireless communication systems 8 are classified into a plurality of classes on the basis of degrees of achievement of wireless communication systems for parameters.
A wireless communication apparatus of the fourth embodiment has a configuration similar to that shown in
When conducting classification on the basis of the parameter 1, it is first determined whether a degree of achievement of a subject wireless communication system 8 as compared with the parameter 1 is 100% (step S71). If the achievement degree is 100%, then the subject wireless communication system 8 is classified into class 1 (step S72). If the achievement degree is not 100%, then it is determined whether the achievement degree is 80% (step S73). If the achievement degree is 80%, then the subject wireless communication system is classified into class 2 (step S74). If the achievement degree is not 80%, then the subject wireless communication system is classified into class 3 (step S75).
When conducting classification on the basis of the parameter 2, it is first determined whether a degree of achievement of a subject wireless communication system 8 as compared with the parameter 2 is 100% (step S76). If the achievement degree is 100%, then the subject wireless communication system 8 is classified into class 1 (step S77). If the achievement degree is not 100%, then it is determined whether the achievement degree is 80% (step S78). If the achievement degree is 80%, then the subject wireless communication system is classified into class 2 (step S79). If the achievement degree is not 80%, then it is determined whether the achievement degree is 50% (step S80). If the achievement degree is 50%, then the subject wireless communication system is classified into class 3 (step S81).
When conducting classification on the basis of the parameter 3, it is first determined whether a degree of achievement of a subject wireless communication system 8 as compared with the parameter 3 is 100% (step S82). If the achievement degree is 100%, then the subject wireless communication system 8 is classified into class 1 (step S83). If the achievement degree is not 100%, then it is determined whether the achievement degree is 50% (step S84). If the achievement degree is 50%, then the subject wireless communication system is classified into class 2 (step S85). If the achievement degree is not 50%, then it is determined whether the achievement degree is 30% (step S86). If the achievement degree is 30%, then the subject wireless communication system is classified into class 3 (step S87).
In selecting a wireless communication system 8 to be used, first, the wireless communication systems 8a and 8c belonging to the class 1 having the highest priority become candidates for selection according to the classification 1 based on the parameter 1 having the highest priority. The wireless communication systems 8b and 8d belonging to the class 3 do not become candidates for selection of the wireless communication systems 8 in any case. Subsequently, according to the classification based on the parameter 2 having the second highest priority, the wireless communication systems 8a and 8c are classified into class 2. Therefore, a wireless communication system 8 to be used is not determined at this stage. According to the classification based on the parameter 3 having the third highest priority, the wireless communication system 8c is classified into the class 2 and the wireless communication system 8a is classified into the class 3. Therefore, the wireless communication system 8c, which belongs to the same class 1 as the wireless communication system 8a on the basis of the parameter 1 having the highest priority and the parameter 2 having the second highest priority, but belongs to the class 2 having a higher priority on the basis of the parameter 3 having the third highest priority, is selected as a wireless communication system 8c to be used.
By thus classifying a plurality of wireless communication systems 8 into classes by taking achievement degrees for the parameters as criteria, detailed classification of the wireless communication systems 8 is conducted. It becomes possible to select a more optimum wireless communication system 8.
An example in which a wireless communication system 8 to be used is selected on the basis of the classification based on achievement degrees of the three parameters provided with a priority order has been described. However, it is not necessary that the number of parameters is always three. A wireless communication system 8 to be used may also be selected on the basis of classification based on the criteria of at least four or at most two parameters provided with a priority order. An example in which wireless communication systems 8 are classified into three classes for each parameter has been described. However, it is not always necessary that wireless communication systems 8 are classified into three classes, but the number of classes may be greater or less than three.
Hereafter, a concrete example of the fourth embodiment will be described.
In
On the basis of the achievement degree for the service area, which is the parameter having the second highest priority, the wireless communication systems 8d and 8e having an achievement degree of 100% are classified into class 1, the wireless communication systems 8a 8g and 8h having an achievement degree of 80% are classified into class 2, and the wireless communication systems 8b, 8c and 8f, in which the parameter of the service area cannot be achieved, are classified into class 3. Since the parameter of the service area cannot be achieved, the wireless communication system 8b, 8c and 8f belonging to the class 3 are not selected in any case as candidates for selection of a wireless communication system 8. Although the wireless communication systems 8 have been classified into three classes in this example, it is not always necessary that the number of classes is three, but the number of classes may be greater than or less than three.
Subsequently, on the basis of the achievement degree for the communication cost, which is the parameter having the third highest priority, the wireless communication systems 8b and 8c having an achievement degree of 100% are classified into class 1, the wireless communication systems 8d and 8e having an achievement degree of 80% are classified into class 2, whereas the wireless communication systems 8g and 8h having an achievement degree of 60% are classified into class 3, the wireless communication system 8f having an achievement degree of 40% is classified into class 4, and the wireless communication system 8a having an achievement degree of 20% is classified into class 5. Although the wireless communication systems 8 have been classified into five classes in this example, it is not always necessary that the number of classes is five, but the number of classes may be greater than or less than five.
In addition, on the basis of the achievement degree for the power dissipation, which is the parameter having the fourth highest priority, the wireless communication systems 8a and 8e having an achievement degree of 100% are classified into class 1, the wireless communication systems 8d and 8f having an achievement degree of 90% are classified into class 2, and the wireless communication systems 8c and 8h having an achievement degree of 50% are classified into class 3, whereas the wireless communication system 8b having an achievement degree of 30% is classified into class 4, and the wireless communication system 8g, in which the parameter of the power dissipation cannot be achieved, is classified into class 5. Since the parameter of the power dissipation cannot be achieved, the wireless communication system 8g belonging to the class 5 is not selected in any case as a candidate for selection of a wireless communication system 8. Although the wireless communication systems 8 have been classified into five classes in this example, it is not always necessary that the number of classes is five, but the number of classes may be greater than or less than three.
A processing procedure conducted by the selector 18 in the fourth embodiment is similar to the flow chart shown in
Subsequently, according to the classification based on the service area, which is the parameter having the second highest priority, the wireless communication systems 8a, 8g and 8h are classified into the class 2, and the wireless communication systems 8b and 8c are classified into the class 3. Therefore, the wireless communication systems 8a, 8g and 8h, which belong to the same class 1 as the wireless communication systems 8b and 8c on the basis of the parameter of QoS having the highest priority, but belongs to the class 2 having a higher priority classified on the basis of the parameter of the service area having the second highest priority, remain as the candidates for selection.
Subsequently, according to the classification based on the communication cost, which is the parameter having the third highest priority, the wireless communication systems 8g and 8h are classified into the class 3, and the wireless communication system 8a is classified into the class 5. Therefore, the wireless communication systems 8g and 8h, which belong to the same class 1 as the wireless communication system 8a on the basis of the parameter of the service area having the second highest priority, but belongs to the class 3 having a higher priority classified on the basis of the parameter of the communication cost having the third highest priority, remain as the candidates for selection. And, according to the classification based on the power dissipation, which is the parameter having the fourth highest priority, the wireless communication system 8h is classified into the class 3, and the wireless communication system 8g is classified into the class 5, for which the parameter of the power dissipation cannot be achieved. The wireless communication system 8h belongs to the same class 3 as the wireless communication system 8g on the basis of the parameter of the communication cost having the third highest priority. However, in the wireless communication system 8g, the parameter of the power dissipation having the fourth priority cannot be achieved. Therefore, the wireless communication system 8g is eliminated from the candidates for selection of a wireless communication system 8. As a result, the wireless communication system 8h is selected as the wireless communication system 8 to be used.
Even if, for example, the wireless communication system 8h selected as the wireless communication system 8 to be used degrades in communication quality and handover to another wireless communication system 8 is to be conducted, the wireless communication system 8g, for which the parameter of the power dissipation cannot be achieved, does not become a candidate for the wireless communication system 8 of handover destination.
Thus, in the fourth embodiment, a wireless communication system 8 is selected according to the classification based on the criteria of achievement degrees respectively for the parameters 1 to 4 provided with a priority order. Therefore, it becomes possible to select an optimum wireless communication system 8 according to more detailed criteria satisfying a plurality of parameters.
An example in which a wireless communication system 8 to be used is selected on the basis of the classification based on the achievement degrees for the four parameters, i.e., the QoS, service area, communication cost and power dissipation provided with a priority order has been described. However, it is not necessary that the criteria for classification are always achievement degrees for the parameters, but a wireless communication system 8 to be used may also be selected according to classification based on other criteria.
In the fifth embodiment, classification is conducted for every a plurality of applications (communication types).
A wireless communication apparatus according to the fifth embodiment has a configuration similar to that shown in
In the case of the application 1, wireless communication systems 8c and 8d, which belong to the class having the highest priority as a result of classification based on the criteria of the parameter P having the highest priority and the parameter R having the second highest priority, become candidates for selection of a wireless communication system 8. In the classification based on the criterion of the parameter Q having the third highest priority, the wireless communication system 8c belongs to class 1 having the highest priority, whereas the wireless communication system 8d belongs to class 2 having the second highest priority. Finally, therefore, the wireless communication system 8c is selected as the wireless communication system 8 to be used.
In the case of the application 2, the wireless communication systems 8a and 8c, which belong to the class having the highest priority as a result of classification based on the criteria of the parameter Q having the highest priority and the parameter P having the second highest priority, become candidates for selection of a wireless communication system 8. In the classification based on the criterion of the parameter S having the third highest priority, the wireless communication system 8a belongs to the class 2 having the second highest priority, whereas the wireless communication system 8c belongs to class 3 having the third highest priority. Finally, therefore, the wireless communication system 8a is selected as the wireless communication system 8 to be used.
By thus changing parameters or the priority order of parameters, it becomes possible to select an optimum wireless communication system 8 according to the application. An example in which a wireless communication system 8 to be used for every application is selected according to the classification based on the criteria of three parameters provided with a priority order has been described. However, it is not necessary that the number of parameters is always three. A wireless communication system 8 to be used may also be selected according to the classification based on the criteria of at least four or at most two parameters provided with a priority order.
Hereafter, a concrete example of the fifth embodiment will be described.
If the application is voice and, for example, talking is conducted while moving, then it is desirable to talk in a wide area and avoid handover in the system as far as possible. In
If it is determined at the step S94 that a wireless communication system 8 belonging to the class 1 is not present, then it is determined whether a wireless communication system 8 belonging to the class 2 is present in candidates (step S96). If such a wireless communication systems 8 is present, then one is selected from the wireless communication systems 8 belonging to the class 2 (step S97).
If it is determined at the step S96 that a wireless communication system 8 belonging to the class 2 is not present, then it is determined whether a wireless communication system 8 belonging to the class 3 is present in candidates (step 598). If such a wireless communication systems 8 is present, then one is selected from the wireless communication systems 8 belonging to the class 3 (step S99). If it is determined at the step S98 that a wireless communication system 8 belonging to the class 3 is not present, then it is determined whether a wireless communication system 8 belonging to the class 4 is present in candidates (step S100). If such a wireless communication systems 8 is present, then one is selected from the wireless communication systems 8 belonging to the class 4 (step S101).
If it is determined at the step S100 that a wireless communication system 8 belonging to the class 4 is not present, then it is determined whether a wireless communication system 8 belonging to the class 5 is present in candidates (step S102). If such a wireless communication systems 8 is present, then one is selected from the wireless communication systems 8 belonging to the class 5 (step S103).
If it is determined at the step S92 that a wireless communication system 8 belonging to the class 1 is not present, then it is determined whether a wireless communication system 8 belonging to the class 2 is present in candidates (step S104). If such a wireless communication systems 8 is present, then the above-described processing of the steps S93 to S103 is conducted.
If it is determined at the step S104 that a wireless communication system 8 belonging to the class 2 is not present, then it is determined whether a wireless communication system 8 belonging to the class 3 is present in candidates (step S105). If such a wireless communication systems 8 is present, then the above-described processing of the steps S93 to S103 is conducted.
If it is determined at the step S105 that a wireless communication system 8 belonging to the class 3 is not present, then it is determined whether a wireless communication system 8 belonging to the class 4 is present in candidates (step S106). If such a wireless communication systems 8 is present, then the above-described processing of the steps S93 to S103 is conducted.
If it is determined at the step S106 that a wireless communication system 8 belonging to the class 4 is not present, then it is determined whether a wireless communication system 8 belonging to the class 5 is present in candidates (step S107). If such a wireless communication systems 8 is present, then the above-described processing of the steps S93 to S103 is conducted.
The processing shown in
If the application is video streaming as shown in
Thus, in the fifth embodiment, it becomes possible to select an optimum wireless communication system 8 according to the application by changing the parameters or the priority order of parameters.
In the sixth embodiment, a plurality of wireless communication systems 8 are classified into a plurality of classes on the basis of degrees of adaptation of wireless communication systems for parameters.
A wireless communication apparatus of the sixth embodiment has a configuration similar to that shown in
If the application is web browsing and most transmitted information is a text and still images, the necessary information transmission rate can be lowered as compared with that in the video streaming. When the application is web browsing, therefore, wireless communication systems 8d, 8e and 8h shown in
On the other hand, when the application is video streaming transmission, wireless communication systems 8a, 8b and 8c, which can satisfy the communication quality (QoS) required for video streaming transmission, and provide a communication quality (QoS) without a surplus or deficiency for the communication quality (QoS) of video streaming transmission, belong to class 1 having the highest priority. Wireless communication systems 8d, 8e and 8h, which cannot satisfy the communication quality (QoS) required for 100% of video streaming transmission, but can satisfy it approximately 50%, belong to class 2 having the second highest priority. Wireless communication systems 8f and 8g, which cannot satisfy the communication quality (QoS) required for video streaming transmission, belong to class 3 having the lowest priority.
When the application is video streaming transmission, the wireless communication systems 8f and 8g belonging to the class 3 classified as non-adaptive for the parameter of the communication quality (QoS) are not selected in any case as candidates for selection of a wireless communication system 8.
Thus, in the sixth embodiment, it becomes possible to utilize the wireless resources of the whole wireless communication system 8 efficiently, by changing the priority order of classification of the wireless communication system 8 or the criteria of the parameters, according to the application to be used even for the same parameters.
An example in which the classification of the parameters or the criteria of the parameters is changed according to a user's request will now be described.
At the ordinary time, the wireless communication systems 8 are classified into classes on the basis of adaptation degrees of a parameter of the service area having the highest priority and a parameter of the cell radius having the second highest priority. It is now supposed that the wireless communication system 8g belonging to the class having the highest priority in these parameters has been selected and used, but communication with a lower communication cost is desired by the user.
It is now supposed that in this case a wireless communication system 8 to be used is selected by using a parameter of the communication cost instead of the parameter of the cell radius as the parameter having the second highest priority. In classification based on adaptation degrees of the parameter of the service area having the highest priority and the parameter of the communication cost having the second highest priority, the wireless communication system 8f belonging to classes having the highest priority is selected as a wireless communication system 8 to be used.
Thus, even for the same application, it becomes possible to select an optimum wireless communication system 8 according to the user's desire, by changing the priority order of the parameters.
An example in which the classification of the parameters or the criteria of the parameters is changed according to the state of the terminal will now be described.
It is supposed that if the residual quantity in the battery is sufficient the wireless communication system 8 to be used is selected by using the parameter of the communication quality (QoS) as the parameter having the highest priority and the parameter of the service area as the parameter having the second highest priority. By classifying the wireless communication systems 8 into classes on the basis of adaptation degrees of these parameters as shown in
Subsequently, it is supposed that in the case where the residual quantity in the battery is small the wireless communication system 8 to be used is selected by using a parameter of power dissipation instead of the parameter of the service area, and adding a parameter of the service area as a parameter having the third highest priority. By classifying the wireless communication systems 8 into classes on the basis of adaptation degrees of these parameters as shown in
Thus, in the sixth embodiment, it becomes possible to select an optimum wireless communication system 8 according to the terminal state, by changing the priority order of the parameters according to the situation of use.
In a seventh embodiment, it is attempted to prevent the communication quality from being degraded even if the user's state changes as in the mobile environment.
A wireless communication apparatus of the seventh embodiment has a configuration similar to that shown in
It is now assumed that at the time of communication start a wireless communication system 8 is selected by using a parameter of the communication quality (QoS) as a parameter having the highest priority, a parameter of the communication cost as a parameter having the second highest priority, and a parameter of the power dissipation as a parameter having the third highest priority. By classifying the wireless communication systems 8 into classes on the basis of adaptation degrees of these parameters as shown in
When the communication is started, the user receives service of video streaming in the stationary state. However, the user starts movement while the user is continuing to receive service of video streaming. For example, the wireless communication system 8c is a wireless communication system 8 having a comparatively narrow service area, such as a local area network. Therefore, it is now supposed that the user gets out of the service area of the wireless communication system 8c as the user moves and consequently the communication quality has degraded. It is supposed that in this case a wireless communication system 8 of handover destination has been selected by using a parameter of the service area as the parameter having the second highest priority instead of the parameter of the communication cost. By classifying the wireless communication systems 8 into classes on the basis of adaptation degrees of these parameters as shown in
Thus, in the seventh embodiment, the parameters during the communication are changed from those at the time of communication start. Even if the user's state has changed, therefore, it becomes possible to select an optimum wireless communication system 8 that does not degrade the communication quality.
In the eighth embodiment, switching of the wireless communication system 8 is conducted by taking the compatibility of the wireless communication systems 8 into consideration.
A wireless communication apparatus of the eighth embodiment has a configuration similar to that shown in
It is now assumed that at the time of communication start a wireless communication system 8 is selected by using a parameter of the communication quality (QoS) as a parameter having the highest priority, a parameter of the communication cost as a parameter having the second highest priority, and a parameter of the power dissipation as a parameter having the third highest priority. By classifying the wireless communication systems 8 into classes on the basis of adaptation degrees of these parameters as shown in
It is now assumed that video streaming transmission was conducted by using the wireless communication system 8c, but the communication quality of the wireless communication system 8c is degraded by interference with another wireless communication system and the video streaming transmission has become difficult. In order to conduct handover to another wireless communication system 8, therefore, a wireless communication system 8 of handover destination must be selected. In order to hold down an image break caused in video streaming transmission by system switching to the minimum as far as possible, however, the network must be switched in a moment. The system switching can be conducted faster by conducting selection on the wireless communication system 8c, which is currently used for communication, and a wireless communication system 8b having high network compatibility. Accordingly, a table in which adaptation degrees of mutual switching among wireless communication systems 8 have been registered by taking network compatibility among the wireless communication systems 8 into consideration is prepared as shown in
It is now supposed that a wireless communication system 8 of handover destination is selected by using a parameter of compatibility with the currently selected wireless communication system 8c instead of the parameter of the communication cost as a parameter having the second highest parameter. The wireless communication systems 8 are classified into classes as shown in
Thus, in the eighth embodiment, information relating to the wireless communication system 8 currently used for communication, such as the network compatibility, is selected as a parameter. Therefore, switching between systems can be conducted rapidly and without a trouble.
In the ninth embodiment, weights of respective parameters are set for each of a plurality of wireless communication systems.
A wireless communication apparatus of the ninth embodiment has a configuration similar to that shown in
In the table shown in
It is now supposed that, for example, the residual quantity in a battery in a terminal is still sufficient when selecting a wireless communication system 8 to be used, at the time of communication start and there is a request for maintaining the quality of voice even at the sacrifice of the communication cost. For example, therefore, it is supposed that a weight 10 is provided for a parameter of the communication quality (QoS), a weight of 10 for a parameter of the service area, a weight of 10 for a parameter of the cell radius, a weight of 7 for a parameter of the power dissipation, and a weight of 5 for a parameter of the communication cost. For a plurality of wireless communication systems 8, a weight provided on the basis of an adaptation degree of a parameter is multiplied by a weight of the parameter itself to yield a product and resultant products are added up. As a result, a wireless communication system 8g having the largest weight is selected as a wireless communication system 8 to be used. In this example, five parameters have been taken into consideration when selecting a wireless communication system 8 to be used. However, it is not necessary that the number of the parameters taken into consideration is always five, but the number of the parameters may be greater than or less than five.
Subsequently, it is supposed that during the communication a candidate for the wireless communication system 8 of handover destination is selected by way of precaution against system switching caused by, for example, degradation in the communication quality of the wireless communication system 8g. It is supposed that in addition to the above-described five parameters the compatibility with the currently used wireless communication system 8g is taken into consideration as a parameter. For example, considering that the system switching must be conducted in a moment because the application is voice, a weight 10 is assigned to the parameter of the compatibility with the wireless communication system 8g. For each of the wireless communication systems 8 other than the wireless communication system 8g, a weight provided on the basis of an adaptation degree of each of the parameters is multiplied by the parameter itself to yield a product, and resultant products are added up. As a result, a wireless communication system 8f having the largest weight is selected as a wireless communication system 8 of handover destination.
Thus, in the ninth embodiment, a weight is provided for each of combinations of the wireless communication systems 8 and the parameters, and a weight is provided for each of the parameters. As a result, it becomes possible to set more detailed parameters, and it becomes possible to select an optimum wireless communication system 8 definitely.
In the tenth embodiment, unnecessary switching of the wireless communication systems 8 is prevented.
It is supposed that at the time of communication start a wireless communication system 8 to be used has been selected by using a parameter of the communication quality (QoS) as a parameter having the highest priority, a parameter of the communication cost as a parameter having the second highest priority, and a parameter of the power dissipation as a parameter having the third highest priority. As shown in
It is now assumed that video streaming transmission was conducted by using the wireless communication system 8c, but the communication quality of the wireless communication system 8c is degraded by interference with another wireless communication system and it has become impossible to satisfy the communication quality (QoS) requested for the video streaming transmission. Since the parameter of the communication quality (QoS) is the specific parameter, system switching to another wireless communication system 8 is conducted. Since a wireless communication system 8 belonging to a class having a priority second to the wireless communication system 8c is a wireless communication system 8b as shown in
It is supposed that the restoration of the quality of the wireless communication system 8c belonging to the highest class in the classification is found during the communication using the wireless communication system 8b on the basis of monitoring of other systems conducted by the system monitor unit 20 or on the basis of control information supplied from a base station of the wireless communication system 8b. Or it is supposed that occurrence of an empty channel in the wireless communication system 8b has been found by the system monitor unit 20. Since the wireless communication system 8c belongs to the highest classes in the classification, originally handover to the wireless communication system 8c is to be conducted. Since the currently used wireless communication system 8b also satisfies the criterion of the parameter of the communication quality (QoS), which is the specific parameter, however, handover to the wireless communication system 8c is not conducted, but the communication using the wireless communication system 8b is continued.
The table shown in
At the time of communication start, a wireless communication system 8g having the largest weight in the sum total values shown in
It is supposed that while video streaming transmission is being conducted by using the wireless communication system 8g the communication quality of the wireless communication system 8g is degraded because, for example, the user enters an underground market or the like and gets out of the service area of the wireless communication system 8g. Since the weight for the parameter of the communication quality (QoS) of the wireless communication system 8g becomes 0, the sum total of weights decreases from 703 to 503 and becomes less than 550, and consequently handover to another wireless communication system 8 is conducted. Wireless communication systems 8 that exceed 550 in the sum total of weights are wireless communication systems 8d, 8e and 8f. The wireless communication system 8f having the largest weight among them is selected as a wireless communication system 8 of handover destination.
It is supposed that the restoration of the quality of the wireless communication system 8g having the largest weight is found during the communication using the wireless communication system 8f on the basis of monitoring of other systems conducted by using the other system monitoring function in the wireless communication apparatus or on the basis of control information supplied from a base station of the wireless communication system 8f. Since the wireless communication system 8g has the largest weight, originally handover to the wireless communication system 8g is to be conducted. Since the currently used wireless communication system 8f also exceeds 550 in sum total of weights and satisfies the criterion of the parameter requested here, however, handover to the wireless communication system 8g is not conducted, but the communication using the wireless communication system 8f is continued.
Summarizing the processing procedure heretofore described, a flow chart shown in
On the other hand, if the decision at the step S134 or S135 yields a negative result, or if the decision at the step S136 yields an affirmative result, then the processing at the step S133 is conducted again. Also when the decision at the step S133 has yielded an affirmative result, the processing at the step S137 is conducted. Thereafter, it is determined whether the communication has finished (step S138). If the communication has not finished, the processing at the step S133 and subsequent steps is repeated.
Thus, in the tenth embodiment, inter-system handover is conducted only when the criterion of the specific parameter is not satisfied or when the sum total of weights has become less than the threshold. As a result, it is possible to avoid unnecessary handover and implement stable communication.
In the eleventh embodiment, a wireless communication system 8 having a high priority is monitored preferentially.
A wireless communication apparatus of the eleventh embodiment has a configuration similar to that shown in
It is supposed that at the time of communication start a wireless communication system 8 to be used has been selected by using a parameter of the communication quality (QoS) as a parameter having the highest priority, a parameter of the service area as a parameter having the second highest priority, and a parameter of the communication cost as a parameter having the third highest priority as shown in
During communication using the wireless communication system 8e, the system monitor unit 20 in the wireless communication apparatus is monitoring wireless communication systems 8 included in a plurality of wireless communication systems 8 other than the wireless communication system 8e by way of precaution against handover to another wireless communication systems 8 caused by degradation or the like in communication quality. As for monitoring other wireless communication systems 8, all of other wireless communication systems 8 are not monitored evenly, but wireless communication systems 8 that become candidates for handover destination are monitored preferentially.
The wireless communication systems 8 to be monitored preferentially are selected by using the classification table shown in
As for a wireless communication system 8 having the next highest priority to be monitored, the wireless communication system 8h, which belongs to class 1 in the parameter of the communication quality (QoS) having the highest priority, but which is classified to be non-adaptive for request in the parameter of the service area having the second highest priority, is not selected. The wireless communication system 8a, which belongs to class 2 in the parameter of the communication quality (QoS) having the highest priority and belongs to class 2 in the parameter of the service area having the second highest priority, is selected.
Monitoring of a wireless communication system 8 having higher priority is, for example, monitoring having a longer time, monitoring having a higher frequency, or a combination of them.
Thus, in the eleventh embodiment, when monitoring a wireless communication system 8 of handover destination, wireless communication systems 8 are provided with a priority order and wireless communication systems 8 having higher priority are monitored preferentially. Therefore, it becomes possible to conduct system switching at the time of handover more certainly and rapidly. And it is possible to provide a seamless wireless communication environment that does not make the user feel a break between wireless communication systems 8.
Number | Date | Country | Kind |
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2003-338350 | Sep 2003 | JP | national |