Technical Field

The present invention relates to a mobile station. Furthermore, the present invention also relates to a method for registering the mobile station to a network.

Background

Presently, a mobile phone is used by a user to make a phone call or to surf on internet. Normally, the mobile phone needs to register to a network when, for example, the mobile phone is switched on, or gets back to a coverage area of a network after leaving its coverage area. When the mobile phone moves into an overlapping area between two networks it can access to, the mobile phone may have a choice in choosing which network for registration. An automatic network selection mode has been developed for helping the mobile phone to register to a network. In the automatic network selection, the mobile phone automatically attempts to register to a network whose signal parameters (for example, signal quality and/or signal strength) are stronger or better than the ones of other networks.

When the mobile phone is roaming, it may enter into an overlapping coverage area between a home network of the mobile phone and a visited network of the mobile phone, and then will apply the automatic network selection mode to choose a network for registration. The home network is a network which is operated by a service provider having a service contract with a user of the mobile phone and provides a communication service to the user in a specified area. Normally, the service provider may have roaming agreements with another service provider to provide continuous service to the user. A network operated by said other service provider is called a visited network of the mobile phone. As shown in figure 1 , the circle 100 represents a coverage area of the home network, and the circle 200 represents a coverage area of the visited network. Just for simplifying the description, the circle 100 is named as home network 100, while the circle 200 is named as visited network 200. In figure 1 , there is an overlapping coverage area between the home network 100 and the visited network 200. As shown in figure 1 , the solid line shows that the mobile phone travels from the home network 100 to the visited network 200, while the dashed line shows that the mobile phone travels from the visited network 200 to the home network 100. When the mobile phone is travelling from the home network 100 to the visited network 200, signal parameters of the home network 100 at point P1 get weaker while signal parameters of the visited network 200 at point P1 are stronger, so the mobile phone will register to the visited network 200, and stays on the visited network 200 as long as the signal parameters of the visited network 200 at point P1 have the best signal parameters. When the mobile phone is travelling back from the visited network 200 to the home network 100, signal parameters of the home network 100 at point P3 are good enough to allow the mobile phone to access the home network 100, but the mobile phone does not register to the home network 100, since signal parameters of the visited network 200 at point P3 are still better than signal parameters of the home network 100 at point P3. Only at point P2, when signal parameters of the visited network 200 deteriorate and become worse than signal parameters of the home network 100, then the mobile phone selects the home network 100 for registration.

It can be seen that in the automatic network selection, the mobile phone takes a long time to register back to its home network 100 when it moves back from the visited network 200 to the home network 100 in the overlapping coverage area of the two networks. Thereby high and unnecessary costs are created for the user of the mobile phone as the user is still roaming although he could already be registered again at his home network.

Summary

An objective of embodiments of present invention is to provide a solution which can allow a mobile station to quickly select a network for registration in an overlapping coverage area of a plurality of networks.

The above objective is achieved by the subject matter of the independent claims. Further advantageous implementation forms of the present invention can be found in the dependent claims corresponding to the possible implementation forms. According to a first aspect of the invention, the above mentioned objective is achieved with a mobile station, which is configured to:

obtain mobile station location information of the mobile station;

determine a movement trend of the mobile station in an overlapping coverage area between a first network and a second network based on the mobile station location information; and

register to the first network or the second network based on the movement trend.

A number of advantages are provided by the present mobile station according to the first aspect. Based on the determined movement trend of the mobile station in the overlapping coverage area, the mobile station can register to a destination network (for example, the first network) as early as possible, since the movement trend actually can predict which network the mobile station will finally move into. Therefore, the procedure for registering the mobile station to a destination network is sped up. Moreover, since the registering to a network is based on the movement trend of the mobiles station, frequent registration handover (e.g. network hopping) between the first network and the second network is avoided, thereby saving battery life of the mobile phone as network registrations are highly power consuming. In a first possible implementation form of the mobile station according to the first aspect, the mobile station is further configured to register to the first network if the mobile station is currently registered to the second network and if the movement trend indicates that the mobile station is moving in a direction from the second network to the first network. The first implementation form has the advantage that the mobile station can register to the first network as quickly as possible.

In a second possible implementation form of the mobile station according to the first possible implementation form of the first aspect or according to the first aspect, the mobile station is further configured to, when being currently registered to the second network, determine a signal quality of the first network; and register to the first network based on the determined signal quality of the first network.

The second implementation form has a further advantage that the mobile station registers to the first network further based on the signal quality of the first network, thereby improving a chance of successfully registering to the first network.

In a third possible implementation form of the mobile station according to the second implementation form of the first aspect, the mobile station is configured to register to the first network if the determined signal quality of the first network is good enough to establish a connection with the first network.

The third implementation form has a further advantage that it is ensured that the mobile station successfully registers to the first network. Hence, unsuccessful registering attempts can be avoided. In a fourth possible implementation form of the mobile station according to the second or third possible implementation form of the first aspect, the mobile station is further configured to when being currently registered to the first network register to the second network only upon the determined signal quality of the first network becoming not good enough to establish a connection with the first network.

The fourth implementation form has a further advantage that it can be avoided to frequently switch registering the mobile station from the first network to the second network. Hence, it can be achieved that the user stays on the first network as long as possible, even when the signal quality of the second network is already better than the one of the first network. This is especially useful if in the case in which the first network is a home network and the second network is a visited network.

In a fifth possible implementation form of the mobile station according to any one of preceding implementation forms of the first aspect or according to the first aspect, the first network is a home network and and the second network is a visited network of the mobile station.

The fifth implementation form has a further advantage that the home network normally charges a user of the mobile station less services fee than the visited network, so the mobile station preferably registering to the home network can save money for the user.

In a sixth possible implementation form of the mobile station according to any of preceding possible implementation forms of the first aspect or according to the first aspect, the mobile station location information comprises information of current location and information of last visited location; and the mobile station is further configured to determine the movement trend by comparing the current location and the last visited location.

In a seventh possible implementation form of the mobile station according to any of preceding possible implementation forms of the first aspect or according to the first aspect, the mobile station is further configured to obtain first network location information related to the first network and second network location information related to the second network, and to determine the movement trend further based on the first network location information and the second network location information.

In a eighth possible implementation form of the mobile station according to the seventh implementation form of the first aspect, the mobile station is further configured to obtain the first network location information and the second network location information from a database or to receive the first network location information and the second network location information over the air. In a ninth possible implementation form of the mobile station according to the seventh or eighth implementation form of the first aspect, the first network location information comprises at least one of the following: coordinates of the overall coverage area of the first network and coordinates of a base station of the first network providing network coverage in the overlapping coverage area; and the second network location information comprises at least one of the following: coordinates of the overall coverage area of the second network and coordinates of a base station of the second network providing network coverage in the overlapping coverage area.

According to a second aspect of the invention, the above mentioned objective is achieved with a method for registering a mobile station to a network.

The method comprises:

obtaining mobile station location information of the mobile station;

determining a movement trend of the mobile station in an overlapping coverage area between a first network and a second network based on the mobile station location information; and

registering the mobile station to the first network or the second network based on the movement trend. Based on the determined movement trend of the mobile station in the overlapping coverage area, the mobile station can register to a destination network (the first network or the second network) as early as possible, since the movement trend actually can predict which network the mobile station will finally move into. Therefore, the procedure for registering the mobile station to a destination network is sped up. Moreover, since the registering to a network is based on the movement trend of the mobile station, frequent registration handover between the first network and the second network is avoided.

The present invention also relates to a computer program, characterized in code means, which when run by processing means causes said processing means to execute any method according to the present invention. Brief Description of the Drawings

The appended drawings are intended to clarify and explain different embodiments of the present invention, in which:

- Fig. 1 shows a roaming behaviour of a mobile station moving in an overlapping coverage area between a home network and a visited network;

- Fig. 2 shows an example of a mobile station registering to a network according to an embodiment of present invention;

- Fig. 3 shows an example of a structure of a mobile station according to an embodiment of the present invention;

- Fig. 4 shows a method for registering a mobile station to a network according to an embodiment of the present invention

Detailed Description

Figure 2 shows how a mobile station 300 registers to a network according to an embodiment of present invention. In figure 2, circle 400 represents a coverage area of a first network, and circle 500 represents a coverage area of a second network. Just for simplifying the following description, circle 400 representing the coverage area of a first network is called as the first network 400 for short, while circle 500 representing the coverage area of a first network is called as the second network 500 for short. The first network 400 overlaps with the second network 500 in some area as shown in figure 2, called the overlapping coverage area.

When the mobile station 300 moves in an area where only the first network 400 or only the second network 500 exists, the mobile station 300 registers to the only network existing in that area according to existing technologies. When the mobile station 300 moves into the overlapping coverage area between the first network 400 and the second network 500, the mobile station chooses a network for registration according to embodiments of the present invention. In an embodiment, after moving into the overlapping coverage area, the mobile station 300 is configured to obtain mobile station location information of itself, to determine a movement trend of itself based on the mobile station location information, and to register to the first network 400 or the second network 500 based on the movement trend. A lot of position or navigation technologies have been developed for determining the position of an object, such as Global Positioning System (GPS) or Assisted Global Positioning System (AGPS). The mobile station 300 can obtain its mobile station location information by applying such existing positioning or navigation technologies or any other suitable positioning system. For example, the mobile station 300 may obtain its mobile station location information from a positioning (e.g. GPS) satellite 600. As the obtained mobile station location information can show moving trajectory of the mobile station 300, the movement trend of the mobile station 300 can be determined as moving toward the second network 500 in a direction from the first network 400 to the second network 500, or as moving toward the first network 400 in a direction from the second network 500 to the first network 400.

Since the movement trend actually can predict which network the mobile station will finally or preferably move into, the mobile station 300 can register to a destination network (for example, the first network 400) or a preferred network as early as possible based on the determined movement trend of the mobile station 400 in the overlapping coverage area. Therefore, the procedure for registering the mobile station 300 to the destination network or the preferred network is sped up. Moreover, frequent registration handover between the first network 400 and the second network 500 is avoided in this embodiment, since registering to a network is based on the movement trend of the mobiles station 300.

In an embodiment, compared to the second network 500, the first network 400 is a preferred network for a user of the mobile station 300. The first network 400 may be the preferred network of the user for reasons such as: the first network 400 charges the user less services fees, and/or provides higher internet rate, and/or has better voice quality, and/or provides the user with other good user experiences. The mobile station 300 is expected to access the preferred network when the mobile station 300 moves into the overlapping coverage area, so the mobile station 300 prefers to register to the first network 400. In this embodiment, if the movement trend indicates that the mobile station 300 is moving toward the first network 400 in the direction from the second network 500 to the first network 400, the mobile station 300 is configured to register to the first network 400. Even if the mobile station 300 is currently registering to the second network 500, the mobile station 300 will also switch its registration from the second network 500 to the first network 400, if the mobile station 300 is moving toward the first network 400 in the direction from the second network 500 to the first network 400. In this embodiment, the mobile station 300 chooses the first network 400 for registration basing on the determined movement trend, so the mobile station 300 can register to the first network 400 as early as possible, thereby speeding up the procedure for registering to a destination or preferred network.

Before the mobile station 300 moves into the overlapping coverage area, the mobile station 300 may stay in an area only belonging to the second network 500's coverage. Normally, the mobile station still stays on the second network 500 after it moves into the overlapping coverage area from the area only belonging to the second network 500's coverage. Sometimes, the mobile station 300 also stays on the second network 500 for other reasons when stepping into the overlapping coverage area. The mobile station 300 staying on the second network 500 means that the mobile station 300 is still registered to the second network 500. In this situation, the mobile station 300 is further configured to determine a signal quality of the first network 400 in the overlapping coverage area, and to switch its registration to the first network 400 further based on the determined signal quality of the first network 400.

In a further embodiment, the mobile station 300 is configured to register to the first network 400 if the determined signal quality of the first network 400 is good enough to establish a connection to the first network 400. Here "good enough" means that the determined signal quality is above a preset signal quality threshold. For example, the preset quality threshold is the worst quality ensuring that the mobile station 300 can successfully communicate with the first network 400 for establishing a connection. Even if the signal quality of the first network 400 obtained by the mobile station 300 is worse than that of the second network 500 obtained by mobile station 300 at the same point in the overlapping coverage area, the mobile station 300 is configured to register to the first network 400 only if the determined signal quality of the first network 400 allows the mobile station to establish a connection to the first network 400. In the overlapping coverage area, the mobile station 300 may move towards the second network 500 in a direction from the first network 400 to the second network 500, or may move towards the first network 400 in a direction from the second network 500 to the first network 400, or may just stay in the overlapping coverage area. In this embodiment, no matter how the mobile station 300 moves, the mobile station 300 keeps its registration to the first network 400 or switches its registration from the second network 500 to the first network 400.

In another embodiment, only upon the determined signal quality of the first network 400 becomes not good enough to establish a connection to the first network 400, the mobile station 300 is further configured to register to the second network 500. In this embodiment, "not good enough" means that the determined signal quality of the first network 400 is worse than the preset signal quality threshold. In a further embodiment, the first network 400 is a home network of the mobile station 300, while the second network 500 is a visited network of the mobile station 300. Normally, the home network charges a user less services fees than the visited network, so the home network is a preferred network for t e user compared to the visited network, and the user always would like to access the home network first in the overlapping coverage area for saving money. In another further embodiment, the mobile station location information of the mobile station 300 comprises information of current location and information of last location visited by the mobile station 300. Information of location of the mobile station 300 may be co-ordinates of the mobiles station 300. The mobile station 300 may obtain its co-ordinates through an existing navigation or position technology such as GPS, and store the obtained co-ordinates. The information of current location may be obtained through the GPS satellite 600, and the information of last visited location can be obtained by reading stored location information. By comparing the current location of the mobile station 300 and the last location visited by the mobile station 300, the mobile station 300 determines the movement trend. The mobile station 300 may be configured to obtain first network location information related to the first network 400, and second network location information related to the second network 500. Then, the movement trend is determined further basing on the first network information and the second network information, and may further indicate which network the mobile station is heading for.

In an embodiment, the mobile station 300 may obtain and store the first network location and the second network location information in advance. The mobile station 300 may store the first network location information and the second network location information into a memory of its own or into a database. When the mobile station 300 determines the movement trend, the mobile station 300 may obtain the first network location information and the second network location information from its memory or from the database. In another embodiment, the mobile station 300 may obtain the first network location information and the second network location information from over the air. For example, the first network location information and the second network information may be broadcasted or dedicated sent to the mobile station 300 by the first network and/or the second network over a wireless connection.

The first network location information comprises at least one of the following: coordinates of the overall coverage area of the first network, coordinates of a base station of the first network providing network coverage in the overlapping coverage area. The second network location information comprises at least one of the following: coordinates of the overall coverage area of the second network, coordinates of a base station of the second network providing network coverage in the overlapping coverage area. The mobile station 300 discussed in the present disclosure may be a mobile telephone, cellular telephone, computer tablet or laptop with wireless capability. The mobile station 300 in the present context may further be, for example, portable, pocket-storable, hand-held, computer-comprised, or vehicle-mounted mobile devices, enabled to communicate voice or data, via the radio access network, with another entity, such as another receiver or a server.

Regarding the mobile station 300 referred in above-mentioned embodiments, figure 3 shows an example of a structure of the mobile station 300. The mobile station comprises

a locating element 301 a processor 303 and a transceiver 304. The locating element 301 is configured to obtain the mobile station location information of the mobile station 300.

The processor 303 is configured to determine a movement trend of the mobile station in an overlapping coverage area between the first network 400 and the second network 500 based on the mobile station location information. The processor 303 is further configured to determine which one of the first network 400 and the second network 500 is for registration based on the movement trend. The processor 303 is further configured to implement a registration procedure for registering the mobile station 300 to the determined network. The transceiver 304 is configured to transmit a message for registration procedure to the determined network for registering the mobile station 300 to the determined network.

In an embodiment, the locating element 301 is configured to store the mobile station location information into a memory 302 of the mobile station 300. The locating element 301 may be further configured to trigger the processor 303 to determine the movement trend of the mobile station 300 once the locating element 301 obtains new mobile station location information. The locating element 301 may be a GPS or AGPS terminal (or chip).

The processor 303 may be further configured to access the memory 302 to obtain information of last location visited by the mobile station 300, and to obtain information of current location of the mobile station 300 directly from the locating element 301 . In another embodiment, the information of current location of the mobile station 300 may be obtained also by accessing the memory 302. The movement trend is determined by the processor 303 by comparing the current location of the mobile station 300 and the last location visited by the mobile station 300. Regarding how the processor 303 determines which one of the first network 400 and the second network 500 is for registration, it can be referred to corresponding parts of forgoing embodiments. With respect to the registration procedure, the processor 303 may apply an existing procedure for registering a mobile station to a specific (or chosen/determined) network. Corresponding to t e mobile station 300 disclosed in above embodiments, figure 3 shows a method which is utilized by the mobile station 300 for registering to a network. The method comprises:

S1 , obtaining mobile station location information of the mobile station 300;

S2, determining a movement trend of the mobile station 300 in an overlapping coverage area between the first network 400 and the second network 500 based on the mobile station location information; and

S3, registering the mobile station 300 to the first network 400 or the second network 500 based on the movement trend.

The method disclosed here is utilized by the mobile station 300 for registering to a network, so the method may further comprise more details discussed in any one of foregoing embodiments. Furthermore, any method according to the present invention may be implemented in a computer program, having code means, which when run by processing means causes the processing means to execute the steps of the method. The computer program is included in a computer readable medium of a computer program product. The computer readable medium may comprises of essentially any memory, such as a ROM (Read-Only Memory), a PROM (Programmable Read-Only Memory), an EPROM (Erasable PROM), a Flash memory, an EEPROM (Electrically Erasable PROM), or a hard disk drive.

Moreover, it is realized by the skilled person that the processor 303 of the present mobile station 300 may comprise, e.g., one or more instances of a Central Processing Unit (CPU), a processing unit, a processing circuit, a processor, an Application Specific Integrated Circuit (ASIC), a microprocessor, or other processing logic that may interpret and execute instructions. The expression "processor" may thus represent a processing circuitry comprising a plurality of processing circuits, such as, e.g., any, some or all of the ones mentioned above. The processing circuitry may further perform data processing functions for inputting, outputting, and processing of data comprising data buffering and device control functions, such as call processing control, user interface control, or the like.

Finally, it should be understood that the present invention is not limited to the embodiments described above, but also relates to and incorporates all embodiments within the scope of the appended independent claims.