JP2014150430A - Radio communication device and control method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication device capable of selecting an optimal handover destination from a plurality of communication networks to perform handover, and a control method of the radio communication device.SOLUTION: A radio communication device includes: a radio transmission/reception unit that can be connected with a plurality of communication networks, and can detect a plurality of connection parameters indicating a state of connection for each of the communication networks; a connection level calculation unit that calculates connection levels of the plurality of communication networks by using the plurality of connection parameters and an expectation value of the connection parameter according to an application to be used; and a control unit that selects a communication network with which to communicate on the basis of the connection levels.

Description

  The present invention relates to a wireless communication apparatus and a control method thereof.

  Wireless communication apparatuses that can be connected to a plurality of communication networks with different wireless communication standards, such as a wireless LAN and a mobile phone network, are already known. In Patent Document 1, a wireless communication device that can be connected to a wireless LAN and a mobile communication network is switched to the wireless LAN when the reception level of the wireless LAN continuously exceeds a threshold for a predetermined period while connected to the mobile communication network. Is disclosed. Further, it is disclosed that, when connected to a wireless LAN, switching to a mobile communication network is performed when the reception level of the wireless LAN continues for a predetermined period and is below a threshold value.

  However, in the technique disclosed in Patent Document 1, since the handover is performed based only on the reception level, a necessary bandwidth cannot be secured at the handover destination, and the communication speed after the handover may decrease. In addition, when there is a communication network with better connection conditions such as S / N ratio (signal-to-noise ratio), data transfer rate, packet error rate, etc., there is a problem that handover is not performed unless the reception level exceeds the threshold value. is there.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a wireless communication apparatus capable of selecting an optimum handover destination from a plurality of communication networks.

  In order to solve the above-described problem, the invention according to claim 1 is directed to a wireless transmission / reception unit capable of connecting to a plurality of communication networks and capable of detecting a plurality of connection parameters indicating a connection state for each of the communication networks; A connection level calculation unit that calculates a connection level of the plurality of communication networks using an expected value of the connection parameter according to a parameter and an application to be used, and a control unit that selects a communication network that performs communication based on the connection level And having.

  According to the embodiment of the present invention, it is possible to provide a radio communication apparatus capable of selecting an optimum handover destination from a plurality of communication networks.

It is a figure which shows the structure of the radio | wireless communication apparatus which concerns on this Embodiment. It is a figure which shows the structure of the radio | wireless transmission / reception part which concerns on this Embodiment. It is a figure which shows the structure of each communication part which concerns on this Embodiment. 3 is a flowchart according to the first embodiment. It is a figure which shows the position of the radio | wireless communication apparatus which concerns on this Embodiment. It is a figure which shows the connection level of each communication network in the time t1 and t2 which concerns on 1st Embodiment. It is a figure which shows the connection level of each communication network from the time t1 to t6 which concerns on 1st Embodiment. It is a flowchart concerning a 2nd embodiment. It is a figure which shows the connection level of each communication network from the time t1 to t4 which concerns on 2nd Embodiment. It is a flowchart concerning a 3rd embodiment. It is a figure which shows the connection level of each communication network in the time t1 to t4 which concerns on 3rd Embodiment. It is a flowchart concerning a 4th embodiment. It is a figure which shows the connection level of each communication network from the time t1 to t4 which concerns on 4th Embodiment. It is a figure which shows the connection level of each communication network from the time t1 to t4 which concerns on 5th Embodiment.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
<Device configuration>
FIG. 1 is an example of a configuration of radio communication apparatus 100 according to the present embodiment.
The wireless communication apparatus 100 includes a wireless transmission / reception unit 101, a connection level calculation unit 102, a position information detection unit 103, an optimum communication network storage unit 104, a control unit 105, a timer unit 106, and an antenna unit 107.

  The wireless transmission / reception unit 101 is configured to be connectable to a plurality of wireless communication networks via the antenna unit 107, and transmits / receives data to / from the communication network specified by the control of the control unit 105. The wireless transmission / reception unit 101 can simultaneously connect to a plurality of wireless communication networks and detect a plurality of connection parameters indicating connection states of the plurality of wireless communication networks. The connection parameters will be described later. The connection level calculation unit 102 calculates the connection level of each communication network using a plurality of connection parameters detected by the wireless transmission / reception unit 101 and the expected value of each connection parameter corresponding to the type of application that performs communication. Details of the connection level will be described later.

  The position information detection unit 103 detects position information indicating the current position of the wireless communication device 100 using a GPS (Global Positioning System) function, information from a base station of the wireless communication network, or the like. The optimum communication network storage unit 104 stores optimum communication network information, which is information on the optimum communication network, corresponding to the position information and the application to be used. The timer unit 106 performs time measurement related to the handover. The control unit 105 selects a communication network for performing communication based on the connection level, and performs handover to another communication network as necessary.

Next, the configuration of the wireless transmission / reception unit 101 shown in FIG. 2 will be described.
The wireless transmission / reception unit 101 includes a third generation mobile phone network communication unit 201, a fourth generation mobile phone network communication unit 202, a Wi-Fi (registered trademark) communication unit 203, and a WiMAX communication unit 204. In addition, this structure is an example to the last, Comprising: You may have a communication part based on another radio | wireless communication standard, and the number of communication parts may be two or more arbitrary numbers.

  The third generation mobile phone network communication unit 201 is a communication unit that can be connected to a third generation mobile phone network, for example, WCDMA (Wideband code Division Multiple Access), HSPA (High-Speed Packet Access), and the like. The fourth generation mobile phone network communication unit 202 is a communication unit that can be connected to a fourth generation mobile phone network, such as LTE (Long-Term Evolution). The Wi-Fi communication unit 203 is a communication unit that can be connected to a wireless LAN compliant with the Wi-Fi standard (IEEE802.11). The WiMAX communication unit 204 is a communication unit that can be connected to a network compliant with the WiMAX standard (IEEE802.16). The wireless transmission / reception unit 101 can be connected simultaneously with a plurality of communication networks having different wireless communication standards.

Next, the configuration of each communication unit 300 in the wireless transmission / reception unit 101 illustrated in FIG. 3 will be described.
Each communication unit 300 in the wireless transmission / reception unit 101 includes a wireless communication I / F (interface) unit 301, an error rate calculation unit 302, a demodulation unit 303, an RSSI extraction unit 304, an S / N ratio calculation unit 305, and a transfer. A speed detection unit 306 and a delay time detection unit 307 are provided.

  The wireless communication I / F unit 301 wirelessly connects to a corresponding wireless standard communication network, and transmits and receives data. The demodulation unit 303 demodulates the signal received by the wireless communication I / F unit 301 and generates a packet. The error rate calculation unit 302 calculates an error rate (%) from a packet generated by the demodulation unit 303 by CRC (Cyclic Redundancy Check) that is a cyclic redundancy check.

  The RSSI extraction unit 304 extracts a received signal strength indication (RSSI) that is the strength of the received signal received by the wireless communication I / F unit 301. The S / N ratio calculation unit 305 calculates the S / N ratio based on the RSSI that is the strength of the received signal extracted by the RSSI extraction unit 304. The S / N ratio is the ratio between the received signal strength and the noise strength. The RSSI extraction unit 304 can detect the received signal strength in a non-radio wave state in which radio waves are not emitted from other terminals as noise strength in a state where the radio wave emission from the antenna unit 107 is stopped.

The transfer rate detection unit 306 calculates the data throughput by summing up each of the uplink transmission data amount and the downlink reception data amount within a predetermined time. The delay time detection unit 307 measures the elapsed time until receiving a packet from the base station, and detects the delay time. For example, a signal including time information is transmitted from the base station, the wireless communication apparatus 100 detects time information from the received signal, and measures a delay time from a difference from the time information possessed by the wireless communication apparatus 100. Regarding the method for measuring the delay time, the measurement of the signal time from the base station is an example, and the time for data transmission from the server of the core network or the communication partner may be measured. Further, the measurement may be performed by a ping function that transmits an echo request to the target node and measures the time until an echo reply is returned from the target node.
With the above configuration, each communication unit 300 can individually measure connection parameters indicating connection states such as an error rate, received signal strength, S / N ratio, data transfer rate, and delay time by each communication unit 300.

<Calculation of connection level>
Here, the connection level described above will be described. The connection level is a value indicating the connection state of each communication network. For connection parameters such as an error rate, received signal strength, S / N ratio, data transfer speed, and delay time from each communication unit 300, and the application to be used. It is calculated using the expected value of each connection parameter set accordingly.

  First, the expected value set according to the application to be used will be described. In the present embodiment, the applications to be used are classified into three categories. The first is “voice call”, which is an application for making a voice call or the like via the web. The second is “video transfer”, which is an application for watching videos and the like via the web. The third is “web browsing”, which is an application other than the above-described voice call and video transfer, such as browsing a web page and sending / receiving an e-mail. Needless to say, the classification of the category is merely an example, and may be another classification.

  And the expected value of each connection parameter required in order to ensure the communication quality of an application is determined for every category of application. For example, referring to the IEEE 802.11 standard, 3GPP standard, standards established by ITU-T (International Telecommunication Union Telecommunication Standardization Sector) (especially G12: Quality of service and network performance), etc., the expected value of each connection parameter Is defined as shown in Table 1.

尚、各接続パラメータの期待値は、一例であって、他の値であっても良い。また、各接続パラメータの期待値は、必要に応じて、手動または自動で変更可能である。

Note that the expected value of each connection parameter is an example, and may be another value. In addition, the expected value of each connection parameter can be changed manually or automatically as necessary.

Next, a parameter level calculation method calculated based on each connection parameter and the application to be used will be described.
First, the S / N ratio, data transfer rate, etc., which indicate that the communication parameter is better as the connection parameter expectation value is positive and the connection parameter value is larger, respectively, using the equation 1 Is calculated. Here, the expected value is a value set for each application to be used, as described above.

式１より、接続パラメータの値が期待値を満足する場合、即ち（接続パラメータの値≧期待値）の場合には、そのパラメータレベルは、「（接続パラメータの値−期待値）／接続パラメータの値」となり、その値は０以上、１以下の値となる。また、接続パラメータの値が期待値を満足しない場合、即ち（接続パラメータの値＜期待値）の場合には、その値は、「−（期待値／接続パラメータの値）」となり、その値は０以下の値となる。

According to Equation 1, when the connection parameter value satisfies the expected value, that is, when (connection parameter value ≧ expected value), the parameter level is “(connection parameter value−expected value) / connection parameter value. Value ", and the value is 0 or more and 1 or less. When the connection parameter value does not satisfy the expected value, that is, when (connection parameter value <expected value), the value is “− (expected value / connection parameter value)”, and the value is The value is 0 or less.

  Next, for an error rate and a delay time indicating that the communication state is better as the value of the connection parameter is smaller, the parameter level is calculated using Equation 2 respectively.

式２より、接続パラメータの値が期待値を満足する場合、即ち（接続パラメータの値≦期待値）の場合には、そのパラメータレベルは、「（期待値−接続パラメータの値）／期待値」となり、その値は、０から１の間の値となる。また、接続パラメータの値が期待値を満足しない場合、即ち（接続パラメータの値＞期待値）の場合には、そのパラメータレベルは「−（接続パラメータの値／期待値）」となり、その値は−１より小さい値となる。
また、期待値が負の値で、接続パラメータの値が大きいほど通信の状態が良いことを示す接続パラメータである受信信号強度については、式２を使ってパラメータレベルを算出する。

From Equation 2, when the connection parameter value satisfies the expected value, that is, when (connection parameter value ≦ expected value), the parameter level is “(expected value−connection parameter value) / expected value”. And the value is between 0 and 1. When the connection parameter value does not satisfy the expected value, that is, when (connection parameter value> expected value), the parameter level is “− (connection parameter value / expected value)”, and the value is It becomes a value smaller than -1.
Further, for the received signal strength, which is a connection parameter indicating that the expected value is a negative value and the communication parameter is better as the connection parameter value is larger, the parameter level is calculated using Equation 2.

  The connection level calculation unit 102 calculates the connection level based on the parameter level calculated for each connection parameter. The connection level is the sum of the parameter levels, calculated as “connection level = reception signal strength parameter level + S / N ratio parameter level + data transfer rate parameter level + error rate parameter level + delay time parameter level”. Is done. A communication network having a larger connection level value is suitable for an application to be used. The connection level has a greater influence on the connection level when there is a connection parameter that does not satisfy the expected value.

  The calculation of the connection level will be described using a specific example. Here, it is assumed that the wireless communication device 100 can communicate with the communication network 1, the communication network 2, and the communication network 3 and is currently communicating with the communication network 2. Also, assume that the expected values according to the connection parameters of each communication network and the application being used are as shown in Table 2.

この場合、全ての接続パラメータが期待値を満足するため、式１及び式２を使って、各パラメータレベルを算出し、接続レベルを計算する。算出結果を以下に示す。
通信綱１との接続レベル = （-82-（-30））/-82 + （36-9）/36 + （3-0.03）/3 + （10-1）/10 + （2000-100）/2000 ≒ 4.22
通信綱２との接続レベル = （-82-（-20））/-82 + （45-9）/40 + （7-0.03）/7 + （10-3）/10 + （2000-300）/2000 ≒ 4.10
通信綱３との接続レベル = （-82-（-20））/-82 + （40-9）/40 + （5-0.03）/5 + （10-2）/10 + （2000-500）/2000 ≒ 4.08
接続レベルの値は大きいほど良いので、現在通信を行っている通信網２よりも、接続レベルが大きい通信網１の方が現在のアプリケーションに適していると判断できるので、通信網１を最適な通信網として判定する。

In this case, since all the connection parameters satisfy the expected value, each parameter level is calculated using Equation 1 and Equation 2, and the connection level is calculated. The calculation results are shown below.
Connection level with Communication Line 1 = (-82-(-30)) /-82 + (36-9) / 36 + (3-0.03) / 3 + (10-1) / 10 + (2000-100) / 2000 ≒ 4.22
Connection level with Communication Line 2 = (-82-(-20)) /-82 + (45-9) / 40 + (7-0.03) / 7 + (10-3) / 10 + (2000-300) / 2000 ≒ 4.10
Connection level with Communication Line 3 = (-82-(-20)) /-82 + (40-9) / 40 + (5-0.03) / 5 + (10-2) / 10 + (2000-500) / 2000 ≒ 4.08
Since a larger connection level value is better, it can be determined that the communication network 1 having a higher connection level is more suitable for the current application than the communication network 2 currently performing communication. Judge as communication network.

  By the way, if the parameter level is calculated by using a single calculation formula for only (expected value−detected value) / expected value or (detected value−expected value) / detected value, there is a possibility that the optimum communication network cannot be selected. There is. For example, the wireless communication apparatus 100 is currently connected to the communication network 2 and each connection parameter and expected value are as shown in Table 3.

ここで、期待値を満足している場合の計算式（期待値−検出値）／期待値、（検出値−期待値）／検出値を使って接続レベルを算出すると、
以下の通りとなる。
通信綱１との接続レベル = （-67-（-45））/-67 + （35-25）/35 + （2.5-0.064）/2.5 + （1-0.9）/1 + （100-90）/100 ≒ 1.79
通信綱２との接続レベル = （-67-（-20））/-67 + （50-25）/50 + （10-0.064）/10 + （1-1.2）/1 + （100-120）/100 ≒ 1.80
通信綱３との接続レベル = （-67-（-30））/-67 + （40-25）/40 + （5-0.064）/5 + （1-2）/1 + （100-500）/100 ≒ -3.09
この場合、接続レベルが一番大きい通信網は通信網２となる。しかし、このとき、通信網２では遅延時間及びエラーレートが期待値を満足していないため、通信品質を保証することができない。つまり、最適な通信網を選択することができていない。

Here, when the connection level is calculated using the formula (expected value−detected value) / expected value and (detected value−expected value) / detected value when the expected value is satisfied,
It becomes as follows.
Connection level with Communication Line 1 = (-67-(-45)) /-67 + (35-25) / 35 + (2.5-0.064) /2.5 + (1-0.9) / 1 + (100-90) / 100 ≒ 1.79
Connection level with Communication Line 2 = (-67-(-20)) /-67 + (50-25) / 50 + (10-0.064) / 10 + (1-1.2) / 1 + (100-120) / 100 ≒ 1.80
Connection level with Communication Line 3 = (-67-(-30)) /-67 + (40-25) / 40 + (5-0.064) / 5 + (1-2) / 1 + (100-500) / 100 ≒ -3.09
In this case, the communication network having the highest connection level is the communication network 2. However, at this time, the communication network 2 cannot guarantee the communication quality because the delay time and error rate do not satisfy the expected values. That is, the optimum communication network cannot be selected.

Here, when the connection level is calculated using Expression 1 and Expression 2 of the present embodiment, the connection level of each communication network is as follows.
Connection level with Communication Line 1 = (-67-(-45)) /-67 + (35-25) / 35 + (2.5-0.064) /2.5 + (1-0.9) / 1 + (100-90) / 100 ≒ 1.79
Connection level with Communication Line 2 = (-67-(-20)) /-67 + (50-25) / 50 + (10-0.064) / 10 + (-1.2 / 1) + (-120/100) ≒ -0.20
Connection level with Communication Line 3 = (-67-(-30)) /-67 + (40-25) / 40 + (5-0.064) / 5 + (-2/1) + (-500/100) ≒ -5.09
Therefore, the communication network 1 that satisfies all the expected values can be selected as the optimum communication network. In other words, if there is a connection parameter that does not satisfy the expected value, the connection level value has a greater influence than the expression when the expected value of Expression 1 and Expression 2 is not satisfied. Therefore, it is difficult to select a communication network including connection parameters that do not satisfy the expected value as an optimal communication network.
Next, a method for selecting an optimum switching destination suitable for the application to be used will be described with a specific example. Assume that the connection parameters of each communication network and the expected values of each application category are as shown in Table 4.

（１）アプリケーションカテゴリが音声通話の場合
この場合、通信網２の遅延時間と、通信網３のエラーレート及び遅延時間が期待値を満足していない。各通信網の接続レベルを式１及び式２を使って計算すると、以下の通りになる。
通信綱１との接続レベル = （-67-（-35））/-67 + （35-25）/35 + （3-0.064）/3 + （1-1）/1 + （100-90）/100 ≒ 1.84
通信綱２との接続レベル = （-67-（-30））/-67 + （40-25）/40 + （10-0.064）/10 + （1-1）/1 + （-300/100） ≒ -1.08
通信綱３との接続レベル = （-67-（-20））/-67 + （45-25）/45 + （5-0.064）/5 + (-3/１） + （-150/100） ≒ -2.37
また、各パラメータレベルと接続レベルの計算結果を表５に示す。

(1) When Application Category is Voice Call In this case, the delay time of the communication network 2 and the error rate and delay time of the communication network 3 do not satisfy the expected values. When the connection level of each communication network is calculated using Equation 1 and Equation 2, the result is as follows.
Connection level with Communication Line 1 = (-67-(-35)) /-67 + (35-25) / 35 + (3-0.064) / 3 + (1-1) / 1 + (100-90) / 100 ≒ 1.84
Connection level with Communication Line 2 = (-67-(-30)) /-67 + (40-25) / 40 + (10-0.064) / 10 + (1-1) / 1 + (-300/100 ) ≒ -1.08
Connection level with Communication Line 3 = (-67-(-20)) /-67 + (45-25) / 45 + (5-0.064) / 5 + (-3/1) + (-150/100) ≒ -2.37
Table 5 shows the calculation results of each parameter level and connection level.

このように、アプリケーションカテゴリが音声通話の場合、通信網２、通信網３が期待値を満足しない接続パラメータを有しており、接続先としてふさわしくないことが判る。そして、期待値を満足する通信網１を最適な通信網として選択することができる。

Thus, when the application category is a voice call, it can be seen that the communication network 2 and the communication network 3 have connection parameters that do not satisfy the expected values, and are not suitable as connection destinations. Then, the communication network 1 that satisfies the expected value can be selected as the optimum communication network.

(2) When the application category is video transfer In this case, the data transfer rate of the communication network 1 and the data transfer rate and error rate of the communication network 3 do not satisfy the expected values. When the connection level of each communication network is calculated using Equation 1 and Equation 2, the result is as follows.
Connection level with Communication Line 1 = (-65-(-35)) /-65 + (35-26) / 35 + (-6/3) + (1-1) / 1 + (500-90) / 500 ≒ -0.46
Connection level with Communication Line 2 = (-65-(-30)) /-65 + (40-26) / 40 + (10-6) / 10 + (1-1) / 1 + (500-300) / 500 ≒ 1.69
Connection level with Communication Line 3 = (-65-(-20)) /-65 + (45-26) / 45 + (-6/5) + (-3/1) + (500-150) / 500 ≒ -2.39
Table 6 shows the calculation results of each parameter level and connection level.

このように、アプリケーションカテゴリがビデオ転送の場合、通信網１、通信網３が期待値を満足しない接続パラメータを有しており、接続先としてふさわしくないことが判る。そして、期待値を満足する通信網２を最適な通信網として選択することができる。

Thus, when the application category is video transfer, it can be seen that the communication network 1 and the communication network 3 have connection parameters that do not satisfy the expected value, and are not suitable as connection destinations. Then, the communication network 2 that satisfies the expected value can be selected as the optimum communication network.

(3) When the application category is web browsing In this case, all communication networks satisfy the expected value. When the connection level of each communication network is calculated using Equation 1 and Equation 2, the result is as follows.
Connection level with Communication Line 1 = (-82-(-35)) /-82 + (35-9) / 35 + (3-0.03) / 3 + (10-1) / 10 + (2000-90) / 2000 ≒ 4.16
Connection level with Communication Line 2 = (-82-(-30)) /-82 + (40-9) / 40 + (10-0.03) / 10 + (10-1) / 10 + (2000-300) / 2000 ≒ 4.16
Connection level with Communication Line 3 = (-82-(-20)) /-82 + (45-9) / 45 + (5-0.03) / 5 + (10-3) / 10 + (2000-150) / 2000 ≒ 4.18
Table 7 shows the calculation results of each parameter level and connection level.

このように、アプリケーションカテゴリがウェブ閲覧の場合、いずれの通信網も期待値を満足しているが、その中でも最も接続レベルの高い通信網３を最適な通信網として選択することができる。

As described above, when the application category is web browsing, any communication network satisfies the expected value, but the communication network 3 with the highest connection level can be selected as the optimum communication network.

  In the above description, the connection level is the sum of the five parameter levels, but this does not limit the scope of the present invention. For example, the connection level may be calculated based on any two or more of the five connection parameters. Alternatively, it may be combined with connection parameters other than the above five connection parameters. In addition, regarding the calculation of the connection level, each parameter level may be weighted and added as necessary instead of the sum of the parameter levels.

<Description of operation>
Next, the operation of radio communication apparatus 100 according to the present embodiment will be described.

[First Embodiment]
FIG. 4 shows a flowchart according to the first embodiment.
In the wireless communication apparatus 100, the wireless transmission / reception unit 101 detects connection parameters of each communication network, and the connection level calculation unit calculates the connection level of each communication network. (S401) Next, it is determined whether there is another communication network having a connection level that exceeds the connection level of the communication network that is currently performing communication. (S402)
If there is another communication network having a connection level that exceeds the connection level of the communication network that is currently communicating, the optimum communication network information corresponding to the current location information and the application used is stored in the optimum communication network storage unit 104. Determine whether it has been. (S403) If there is no other communication network having a connection level exceeding the connection level of the current communication network, the process returns to step S401, and another communication network having a connection level exceeding the connection level of the current communication network. Repeat the process until is found.

If it is determined in step S403 that the optimum communication network storage unit 104 stores the current position information and the optimum communication network information corresponding to the application to be used, the stored optimum communication network is selected. (S405) On the other hand, if it is determined that the optimum communication network information is not stored in the optimum communication network storage unit 104, a timer is started and another communication having a connection level exceeding the connection level of the current communication network. Record the duration of the state of the net. (S404) Using the recording result of the timer, it is determined whether there is a communication network that continuously exceeds the connection level of the current communication network for a predetermined time. (S407)
In step S407, if there is a communication network that continuously exceeds the connection level of the current communication network for a predetermined time, the communication network that continuously exceeds the connection level of the current communication network for a predetermined time is selected as the optimum communication network. (S408) Thereafter, the timer is reset, and the current location information, the application information used, and the information of the selected optimum communication network are stored in the optimum communication network storage unit 104. (S409) On the other hand, in step S407, if there is no communication network that continuously exceeds the connection level of the current communication network for a predetermined time, the timer is reset (S406), the process returns to step S401, and the process is started again. . Finally, in step S410, handover is performed to the optimum communication network selected in step S405 or step S408. (S410)
With the above operation, the wireless communication device 100 can perform handover by selecting an optimum handover destination from a plurality of communication networks.

Next, the operation of the first embodiment will be further described with a specific example.
FIG. 5 is a schematic diagram for explaining the position of the wireless communication device 100 at times t1 and t2. In FIG. 5, it is assumed that wireless communication apparatus 100 is located at location A at time t1 and moved to location B at time t2. Here, the method for determining the locations A to E can be arbitrarily set according to the request of the system or the user. For example, the locations A to E may be determined for each predetermined distance based on the position information from the position information detection unit 103. Alternatively, the locations A to E may be determined by a combination of base stations exceeding a predetermined reception level. Alternatively, it may be determined that the location has moved when a new base station or communication network is detected or when an existing base station or communication network cannot be detected. Alternatively, when the user determines that the communication state is bad, a new place may be added by manual operation.

(When there is optimum network information)
It is assumed that optimum communication network information is stored in the optimum communication network storage unit 104 as shown in Table 8. The wireless communication device 100 can communicate with the communication network 1, the communication network 2, and the communication network 3, and the relationship between the connection levels of the communication networks at the times t1 and t2 is as shown in FIG.

ここで、無線通信装置１００は、時刻ｔ１に場所Ａにおいて通信網１と音声通話（例えばインターネットを利用したIP電話等）を開始し、時刻ｔ２に音声通話を継続したまま場所Ｂに移動するものとする。このとき、図６より、時刻ｔ２において、現在通信中の通信網１よりも接続レベルが高い通信網２があるため、最適通信網の選択を行う必要がある。ここで、最適通信網記憶部１０４には現在の位置Ｂに対応する最適通信網情報として通信網２が記憶されているので、制御部１０５は最適通信網情報に基づいて、無線送受信部１０１に通信網２へのハンドオーバを指示する。

Here, the wireless communication device 100 starts a voice call (for example, an IP phone using the Internet) at the location A at the time t1 and moves to the location B while continuing the voice call at the time t2. And At this time, as shown in FIG. 6, since there is a communication network 2 having a higher connection level than the currently communicating communication network 1 at time t2, it is necessary to select an optimum communication network. Here, since the communication network 2 is stored in the optimum communication network storage unit 104 as the optimum communication network information corresponding to the current position B, the control unit 105 stores the information in the wireless transmission / reception unit 101 based on the optimum communication network information. A handover to the communication network 2 is instructed.

  As described above, when the currently communicating communication network is not the optimum communication network, the wireless communication device 100 communicates with the optimum communication network stored in the optimum communication network storage unit 104 according to the current location information and the application used. You can switch destinations.

(When there is no optimal network information)
Next, it is assumed that the optimum communication network storage unit 104 does not store optimum communication network information. The wireless communication apparatus 100 can communicate with the communication network 1, the communication network 2, and the communication network 3, and the connection levels of the communication networks from time t1 to time t6 are as shown in FIG. It is assumed that communication is performed with the communication network 1 at time t1, the same application is used from time t1 to time t6, and the application category is not changed.

In this state, the operation when there is no optimum communication network information will be described with reference to FIG.
At time t1, the wireless communication device 100 is communicating with the communication network 1 at a location A in FIG. When the wireless communication apparatus 100 moves to the location B in FIG. 5 at time t2, since there is a communication network (communication networks 2 and 3) having a higher connection level than the communication network 1 currently communicating from FIG. It is necessary to select a network. Here, since there is no optimum communication network information corresponding to the current position B in the optimum communication network storage unit 104, the duration of a state in which there is a communication network exceeding the connection level of the communication network 1 currently communicating is recorded. Then, it is determined whether there is a communication network that continuously exceeds the connection level of the communication network 1 that is currently communicating for a predetermined time.

  At time t3, there is no communication network exceeding the connection level of the currently communicating communication network 1. At this time, the duration of the state in which there is a communication network exceeding the connection level with the communication network 1 does not exceed the predetermined time T, so the radio communication device 100 does not perform handover.

  At time t4, since there is a communication network that exceeds the connection level of the communication network 1 that is currently communicating, it is necessary to select the optimum communication network. Here, since there is no optimum communication network information in the optimum communication network storage unit 104, the duration of the state in which there is a communication network exceeding the connection level of the currently communicating communication network 1 is recorded. Then, it is determined whether there is a communication network that continuously exceeds the connection level of the communication network 1 that is currently communicating for a predetermined time.

  At time t6, since the connection level of the communication network 3 continuously exceeds the connection level of the communication network 1 for a predetermined period, the communication network 3 is determined as the optimum communication network. Then, the current location information, information on the application to be used, and the selected optimum communication network are stored in the optimum communication network storage unit 104, and a handover is performed to the communication network 3.

  As described above, according to the present embodiment, radio communication apparatus 100 can select an optimal handover destination communication network when the communication network in communication is not the optimal communication network. In addition, when there is the optimum communication network information according to the current location information and the application to be used, an optimum communication network can be obtained in a shorter time than when there is no optimum communication network information based on the stored optimum communication network information. Handover is possible. Further, when there is no optimum communication network information, stable handover can be performed by selecting a communication network that continuously exceeds the connection level of the currently communicating communication network for a predetermined time as the optimum communication network. Further, when there is no optimum communication network information, the selected optimum communication network is stored in the optimum communication network storage unit 104 together with the current position information and use application information, so that the next and subsequent handovers can be speeded up.

[Second Embodiment]
FIG. 8 shows a flowchart according to the second embodiment.
Since the operations from step S801 to step S807 are the same as those in the first embodiment, description thereof will be omitted, and description will be made focusing on differences from the first embodiment.

This embodiment shows an operation in the case where there are a plurality of communication networks exceeding the connection level of the currently communicating communication network in step S807 (corresponding to step S407 in the first embodiment). If it is determined in step S807 that there is a communication network exceeding the connection level of the currently communicating communication network, it is determined in step S808 whether there are a plurality of communication networks exceeding the connection level of the currently communicating communication network. To do. If the number of communication networks exceeding the connection level of the currently communicating communication network is more than one, the communication network with the highest connection level among the communication networks exceeding the connection level of the currently communicating communication network is the optimum communication network. Choose as. (S809) If there are not a plurality of communication networks exceeding the connection level of the currently communicating communication network, the communication network exceeding the connection level of the currently communicating communication network is selected as the optimum communication network. Thereafter, the timer is reset, and the current location information, application application information, and selected optimum communication network information are stored in the optimum communication network storage unit 104. (S810) Handover is performed to the optimal communication network selected last. (S811)
Next, the operation of the second embodiment will be further described with a specific example.
FIG. 9 is a diagram illustrating a connection level state of each communication unit 300 from time t1 to time t4. In addition, it is assumed that the wireless communication device 100 does not store optimum communication network information.

  Referring to FIG. 9, since there is a communication network (communication networks 2 and 3) having a higher connection level than the communication network 1 that is currently communicating at time t2, it is necessary to select an optimum communication network. Here, since there is no optimum communication network information in the optimum communication network storage unit 104, the duration of the state in which there is a communication network exceeding the connection level of the currently communicating communication network 1 is recorded, and the connection level of the communication network 1 is recorded. It is determined whether there is a communication network that continuously exceeds a predetermined time. At time t4, since the connection levels of the communication networks 2 and 3 continuously exceed the connection level of the communication network 1 for a predetermined period, the number of communication networks that exceed the connection level of the communication network 1 for a predetermined period is plural. At this time (time t4), the wireless communication device 100 selects the communication network 3 with the highest connection level as the optimum communication network, and uses the current location information, the application to be used, and the selected optimum communication network as the optimum communication network information. Store in the optimal communication network storage unit 104 and perform handover.

  As described above, according to the present embodiment, even when there are a plurality of communication networks that exceed the connection level of the currently communicating communication network, handover to the optimum communication network is possible. Therefore, it is possible to cope with the case where the number of wireless communication standards to be supported further increases in the future.

[Third Embodiment]
FIG. 10 shows a flowchart according to the third embodiment. Table 9 shows important parameters designated for each application category. In this embodiment, in the second embodiment, there are a plurality of communication networks that continuously exceed the connection level of the communication network in communication for a predetermined period, and the operation when the value of the connection level is the same. Is shown. Note that the same connection level value here means that the calculated connection level value does not exactly match up to a few digits after the decimal point. , Including the case where the difference is within a certain range and substantially equivalent.

本実施の形態では、通信中の通信網の接続レベルを所定期間継続して超える複数の通信網の接続レベルの値が同じ場合には、表９に示すアプリケーションカテゴリ毎に指定された重要パラメータのパラメータレベルの和を比較して最適通信網を選択する。

In this embodiment, when the connection level values of a plurality of communication networks that continuously exceed the connection level of the communication network in communication for a predetermined period are the same, the important parameters specified for each application category shown in Table 9 The optimum communication network is selected by comparing the sum of the parameter levels.

  Here, the operation of the present embodiment will be described with reference to FIG. Note that the operations from step S1001 to step S1008 are the same as those in the second embodiment, and therefore the description will focus on the parts that are different from those in the second embodiment.

In step S1008 (corresponding to S808 in the second embodiment), when there are a plurality of communication networks exceeding the connection level of the communication network in communication, the value of the connection level of the communication network exceeding the connection level of the communication network in communication Determine if they are the same. (S1009) If the connection level value of the communication network that exceeds the connection level of the communication network in communication is the same, the parameter level of the important parameter specified for each application category shown in Table 9 according to the application being used The communication network with the largest sum is selected. (S1010) On the other hand, if the connection level value of the communication network exceeding the connection level of the communication network in communication is not the same, the communication network having the largest connection level value is selected. (S1011) Thereafter, the timer is reset, and the current location information, the application application information and the selected optimum communication network information are stored in the optimum communication network storage unit 104. (S1012) Handover is performed to the optimum communication network selected last. (S1013)
Next, the operation of the third embodiment will be described with a specific example.
FIG. 11 is a diagram illustrating a connection level state of each communication unit 300 from time t1 to time t4. In addition, it is assumed that the wireless communication device 100 does not store optimum communication network information. Further, Table 10 shows connection parameters and connection levels of each communication network at time t4. It is assumed that the application used is a voice call.

図１１を参照すると、時刻ｔ２において、現在通信中の通信網１よりも接続レベルが高い通信網（通信網２及び３）があるため、最適通信網の選択を行う必要がある。ここで、最適通信網記憶部１０４には最適通信網情報がないので、現在通信中の通信網１の接続レベルを超える通信網が有る状態の継続時間を記録し、通信網１の接続レベルを所定時間継続して超える通信網があるかどうかを判定する。時刻ｔ４において、通信網２及び３の接続レベルが通信網１の接続レベルを所定期間継続して超えるので、通信網１の接続レベルを所定期間継続して超える通信網の数が複数となる。このとき、表１０に示すように通信網２と通信網３の接続レベルの値が同じであるため、表９に示す重要パラメータのパラメータレベルの和が最も大きい通信網を選択する。ここでは、利用アプリケーションが音声通話であるため、重要パラメータは、データ転送速度、遅延時間、エラーレートの３つである。この３つの重要パラメータのパラメータレベルの和を計算すると以下のようになる。
通信綱２の重要パラメータレベルの和 = （10-0.064）/10 + （1-1）/1 + （100-98）/100 ≒ 1.01
通信綱３の重要パラメータレベルの和 = （5-0.064）/5 + (1-1)/１ + （100-80）/100 ≒ 1.18
この計算結果より、重要パラメータのパラメータレベルの和が最も大きい通信網３を最適通信網として選択し、現在の位置情報、利用アプリケーション及び選定された最適通信網を最適通信網情報として最適通信網記憶部１０４に記憶し、ハンドオーバを行う。

Referring to FIG. 11, since there is a communication network (communication networks 2 and 3) whose connection level is higher than that of the communication network 1 that is currently communicating at time t2, it is necessary to select an optimum communication network. Here, since there is no optimum communication network information in the optimum communication network storage unit 104, the duration of the state in which there is a communication network exceeding the connection level of the currently communicating communication network 1 is recorded, and the connection level of the communication network 1 is recorded. It is determined whether there is a communication network that continuously exceeds a predetermined time. At time t4, since the connection levels of the communication networks 2 and 3 continuously exceed the connection level of the communication network 1 for a predetermined period, the number of communication networks that exceed the connection level of the communication network 1 for a predetermined period is plural. At this time, since the values of the connection levels of the communication network 2 and the communication network 3 are the same as shown in Table 10, the communication network having the largest sum of the parameter levels of the important parameters shown in Table 9 is selected. Here, since the application used is a voice call, there are three important parameters: data transfer speed, delay time, and error rate. The sum of the parameter levels of these three important parameters is calculated as follows.
Sum of important parameter levels of Communication Line 2 = (10-0.064) / 10 + (1-1) / 1 + (100-98) / 100 ≒ 1.01
Sum of important parameter levels of communication line 3 = (5-0.064) / 5 + (1-1) / 1 + (100-80) / 100 ≒ 1.18
Based on the calculation result, the communication network 3 having the largest sum of the parameter levels of the important parameters is selected as the optimum communication network, and the current location information, the application used and the selected optimum communication network are stored as the optimum communication network information. Store in the unit 104 and perform handover.

  As described above, according to the present embodiment, even when there are a plurality of communication networks that exceed the connection level of the currently communicating communication network and the connection levels are the same, the optimum handover destination communication network can be selected. . Therefore, even if the number of wireless communication standards to be supported in the future increases further, it can be sufficiently handled.

[Fourth Embodiment]
FIG. 12 shows a flowchart according to the fourth embodiment.
Since operations other than step S1205 are the same as those in the first embodiment, the description will focus on differences from the first example. The present embodiment shows an example of the operation when it is determined in step S1205 (corresponding to step 403 in the first embodiment) that there is optimum communication network information corresponding to the current location information and the application to be used. Is.

  If it is determined in step S1003 in FIG. 10 that there is optimum communication network information corresponding to the current location information and application, a communication network that exceeds the connection level of the communication network in communication is stored. Determine if it matches the information. (S1205) If the communication network determined to exceed the connection level of the communication network in communication from the calculation result of the connection level matches the optimum communication network stored in the optimum communication network storage unit 104, the storage is performed. Select the optimal network. (S1208) On the other hand, if the communication network determined to exceed the connection level of the communication network in communication does not match the optimum communication network stored in the optimum communication network storage unit 104, the process proceeds to step S1204. The same processing is performed as when there is no stored optimum communication network.

Next, the operation of the fourth embodiment will be described with a specific example.
First, referring to FIG. 5, it is assumed that radio communication apparatus 100 is located at location A at time t1 and has moved to location B at time t2. Further, it is assumed that optimum communication network information is stored in the optimum communication network storage unit 104 as shown in Table 11. Further, it is assumed that the wireless communication device 100 can communicate with the communication network 1, the communication network 2, and the communication network 3, and the relationship between the connection levels of the communication networks from time t1 to time t4 is as shown in FIG. Note that the wireless communication apparatus 100 uses web browsing as a use application, and the category is not changed from time t1 to time t4.

図５及び図１３より、時刻ｔ１において、無線通信装置１００は場所Ａで通信網１と通信を行っている。時刻ｔ２において、無線通信装置１００が場所Ｂに移動すると、現在通信中の通信網１よりも接続レベルが高い通信網（通信網２及び３）があるので、最適通信網の選択を行う必要がある。このとき、表１１より、最適通信網記憶部１０４には、現在の位置情報（場所Ｂ）及び利用アプリケーション（ウェブ閲覧）に応じた最適通信網として、通信網１が記憶されている。従って、最適通信網記憶部１０４に記憶された最適通信網である通信網１よりも、接続レベルが高い通信網（通信網２及び３）がある状態となっている、即ち、記憶された最適通信網情報と、接続レベルの計算結果が一致しないと判断できる。

5 and 13, the wireless communication device 100 is communicating with the communication network 1 at the location A at time t1. When the wireless communication apparatus 100 moves to the location B at time t2, there is a communication network (communication networks 2 and 3) having a higher connection level than the currently communicating communication network 1, so it is necessary to select the optimum communication network. is there. At this time, from Table 11, the communication network 1 is stored in the optimum communication network storage unit 104 as the optimum communication network according to the current position information (location B) and the application used (web browsing). Therefore, there is a communication network (communication networks 2 and 3) having a higher connection level than the communication network 1 which is the optimal communication network stored in the optimal communication network storage unit 104, that is, the stored optimal network It can be determined that the communication network information does not match the connection level calculation result.

  Therefore, the wireless communication device 100 determines whether there is a communication network that continuously exceeds the connection level of the communication network 1 that is currently communicating for a predetermined time. At time t4 in FIG. 13, since there is a communication network that continuously exceeds the connection level of the currently communicating communication network 1 for a predetermined time or more, the communication network 3 is determined to be the optimum communication network. Next, the current location information, use application information, and information of the selected optimum communication network are stored in the optimum communication network storage unit 104, and handover is performed. Here, the updated optimum communication network information is shown in Table 12.

以上より、本実施の形態によれば、無線通信装置１００は、記憶された最適通信網情報を更新する必要がある場合、例えば、新規基地局が設置された場合等には、記憶された最適通信網情報を更新することができる。

As described above, according to the present embodiment, the radio communication apparatus 100 needs to update the stored optimum communication network information, for example, when a new base station is installed, etc. Communication network information can be updated.

[Fifth Embodiment]
In the present embodiment, the operation when the category of an application is changed during communication will be described with a specific example. First, for the sake of explanation, it is assumed that the connection parameters of each communication network at each time are not changed with the values shown in Table 13. The connection level for each application category of the communication network at this time is as shown in Table 14. The wireless communication device 100 performs a voice call at time t1, and changes the application category to video transfer at time t2.

図１４は、最適通信網記憶部１０４が、現在の位置情報及び利用アプリケーションに応じた最適通信網情報を記憶していない場合の、時刻ｔ１からｔ４における各通信網の接続レベルを示す図である。図１４のｔ１において、無線通信装置１００は、音声通話を開始する。このとき、音声通話時の接続レベルが最も高い通信網１と接続する。時刻ｔ２において、アプリケーションのカテゴリが音声通話からビデオ転送に変更されると、接続レベル算出部１０２は、ビデオ転送時の期待値に基づいて接続レベルの再計算を行う。このとき、現在通信中の通信網１の接続レベルを超える通信網（通信網２）があるため、最適通信網の選択を行う必要がある。

FIG. 14 is a diagram illustrating connection levels of communication networks from time t1 to time t4 when the optimal communication network storage unit 104 does not store optimal communication network information according to current location information and usage applications. . At t1 in FIG. 14, the wireless communication device 100 starts a voice call. At this time, the communication network 1 having the highest connection level during a voice call is connected. When the application category is changed from voice call to video transfer at time t2, the connection level calculation unit 102 recalculates the connection level based on the expected value at the time of video transfer. At this time, since there is a communication network (communication network 2) exceeding the connection level of the currently communicating communication network 1, it is necessary to select the optimum communication network.

  Here, when there is no optimal communication network information in the optimal communication network storage unit 104, it is determined whether there is a communication network that continuously exceeds the connection level of the communication network in communication for a predetermined time. At time t4, since there is a communication network 2 that continuously exceeds the connection level of the current communication network for a predetermined time, the communication network 2 is selected as the optimum communication network, and handover is performed.

  On the other hand, when the optimum communication network storage unit 104 stores the communication network 2 as the optimum communication network information corresponding to the current location information and the application used at time t2, the optimum communication network information is stored based on the stored optimum communication network information. Thus, handover is performed to the communication network 2 which is the optimum communication network.

  As described above, according to the present embodiment, radio communication apparatus 100 can be handed over to the optimum communication network even when the currently communicating communication network is no longer the optimum communication network due to the change of the application used.

  In the present embodiment as well, if there are a plurality of communication networks that continuously exceed the connection level of the current communication network for a predetermined time, the same processing as in the second and third embodiments is possible. Further, when the stored optimum communication network needs to be updated, the same processing as in the fourth embodiment is possible.

  As described above, according to each embodiment of the present invention, it is possible to provide a radio communication apparatus capable of selecting an optimum handover destination from a plurality of communication networks and a control method therefor.

  Further, since the connection level is calculated based on the expected value according to the application that performs communication and the optimum communication network is selected, the optimum communication network for the application in use can be selected as the handover destination.

DESCRIPTION OF SYMBOLS 100 Wireless communication apparatus 101 Wireless transmission / reception part 102 Connection level calculation part 103 Location information detection part 104 Optimal communication network memory | storage part 105 Control part 106 Timer part 300 Each communication part

JP 2012-4659

Claims (10)

A wireless transceiver capable of connecting to a plurality of communication networks and capable of detecting a plurality of connection parameters indicating a connection state for each of the communication networks;
A connection level calculation unit that calculates a connection level of the plurality of communication networks using the connection parameter expected value of the connection parameter according to the connection parameter and an application to be used;
A control unit for selecting a communication network for performing communication based on the connection level;
A wireless communication device. A position information detector for detecting position information indicating the current position;
An optimum communication network storage unit for storing optimum communication network information indicating an optimum communication network corresponding to the position information and the application to be used, and
When the optimum communication network storage unit stores the optimum communication network information corresponding to the location information and the application to be used,
The wireless communication apparatus according to claim 1, wherein a communication network that performs the communication is selected according to the optimal communication network information. When the optimal communication network storage unit does not store the optimal communication network information corresponding to the location information and the application to be used,
Selecting a communication network having the connection level that continuously exceeds the connection level of the communication network that is currently communicating for a predetermined period as an optimal communication network;
Storing the location information, the application information to be used, and the optimum communication network in the optimum communication network storage unit as the optimum communication network information;
The wireless communication apparatus according to claim 2, wherein the optimum communication network is selected as a communication network that performs the communication.   The control unit, when there are a plurality of communication networks having the connection level that continuously exceeds the connection level of the communication network that is currently performing communication for a predetermined period, the communication network having the largest value of the connection level, The wireless communication apparatus according to claim 3, wherein the wireless communication apparatus is selected as the optimum communication network. The control unit includes a plurality of communication networks having the connection level that continuously exceed the connection level of a communication network that is currently performing communication for a predetermined period, and a difference in values of the connection levels of the plurality of communication networks is predetermined. If it is within the range of
4. The wireless communication apparatus according to claim 3, wherein a communication network having a largest sum of parameter levels of important parameters set for each application to be used is selected as the optimum communication network. The control unit, even when the optimal communication network storage unit stores the location information and the optimal communication network information corresponding to the application to be used,
Selecting a communication network having the connection level that continuously exceeds the connection level of the communication network that is currently communicating for a predetermined period as an optimal communication network;
The wireless communication apparatus according to claim 2, wherein the position information, the application information to be used, and the optimum communication network can be stored in the optimum communication network storage unit as the optimum communication network information.   The wireless communication apparatus according to claim 1, wherein the plurality of connection parameters include at least a data transfer rate or an error rate.   The wireless transmission / reception unit is connected to the plurality of communication networks at the same time, and is capable of detecting reception signal strength, S / N ratio, error rate, data transfer rate, and delay time of the plurality of communication networks. The wireless communication device according to any one of claims 1 to 6. The connection level calculation unit calculates the parameter level of the connection parameter, which is a positive value and the quality is higher as the value is larger, according to Equation 1,
The parameter level of the connection parameter that is better in quality as the value is smaller is calculated by Equation 2,
The wireless communication apparatus according to claim 1, wherein the connection level is calculated based on the calculated parameter level of each connection parameter.

Detecting a plurality of connection parameters indicating a connection state for each of a plurality of communication networks;
Calculating connection levels of the plurality of communication networks, using expected values of the connection parameters according to the plurality of connection parameters and an application to be used;
Selecting a communication network for performing communication based on the connection level;
A method for controlling a wireless communication device including:

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