KR20100071879A - Method for reselecting cell between neighboring cells based on different radio technologies - Google Patents

Abstract

PURPOSE: A method for re-selecting cells among adjacent cells on different RAT(Radio Access Technology) is provided to confirm conditions to move terminals to different kinds of the RAT, and to offer efficient procedures for movement of the terminal. CONSTITUTION: A method for re-selecting cells among adjacent cells on different RAT includes the following steps: determining whether a measured value of a serving cell is lower than a threshold value or not(S113); determining a proper cell among neighboring cells in case the measured value is lower than the threshold value(S115); determining the cells of the priority lower than the serving cell in case the proper cells is not detected; and reselecting the cell among the adjacent cells in case the proper cells are detected in the same priority(S116).

Description

METHODE FOR RESELECTING CELL BETWEEN NEIGHBORING CELLS BASED ON DIFFERENT RADIO TECHNOLOGIES}

The present invention relates to mobile communications, and more particularly, to a method for reselecting a cell among neighboring cells based on different radio access technologies.

Second generation mobile communication refers to digital transmission and reception of voice, such as CDMA and GSM. In addition to the GSM, GPRS has been proposed. The GPRS is a technology for providing a packet switched data service based on the GSM system. The GSM / GPRS is a system based on TDMA.

Third generation mobile communication refers to the ability to transmit and receive images and data as well as voice, and the Third Generation Partnership Project (3GPP) developed the mobile communication system (IMT-2000) technology, and radio access technology (Radio Access). Technology, referred to as RAT). In this way, both IMT-2000 technology and radio access technology (RAT), for example, WCDMA, are collectively called UMTS (Universal Mobile Telecommunication System) in Europe. UTRAN stands for UMTS Terrestrial Radio Access Network.

Meanwhile, in the third generation mobile communication, data traffic is expected to increase rapidly in the future, and standardization work for making a long-band evolutionary network (LTE) with higher bandwidth is in progress.

In LTE, the term Evolved-UTRAN (E-UTRAN) is used, and in E-UTRAN, Orthogonal Frequency Division Multiple Access (OFDMA) is used as a radio access technology (RAT).

Meanwhile, as described above, various radio access technologies (RATs) exist, so that interoperability between the second generation GSM / GPRS and the third generation UMTS is problematic. In addition, even when a new radio access technology (RAT) such as E-UTRAN emerges, interoperability between RATs becomes a problem.

To solve this problem, operators provide roaming between RATs. This is because an operator can also recycle existing equipment. To this end, UEs may support multi-RAT. The terminal may measure (eg, measured power, reference signal received power (RSRP), SNR, etc.) of cells of another neighboring RAT, and move to a cell of the other RAT. In this way, the terminal can receive a better signal while maintaining the quality of service.

However, in the related art, conditions and procedures for moving a cell of a RAT different from the RAT to which the UE currently belongs are not presented.

Therefore, conventionally, the terminal cannot move from one RAT to another type of RAT.

Accordingly, an object of the present invention is to determine the conditions under which a terminal can move to a cell of a different type of RAT.

Another object of the present invention is to provide an efficient procedure for allowing a terminal to move to a cell of a different type of RAT.

In order to achieve the above object, the present invention allows a terminal to move to a cell of a different type of RAT based on priority.

In addition, to achieve the above object, the present invention provides a method for reselecting a cell among neighboring cells based on different radio access technologies. The cell reselection method includes determining whether a measurement value for a serving cell is lower than a threshold value; Determining whether there is a suitable cell among neighboring cells having the same priority as the serving cell when the threshold value is lower than the threshold; If there is no suitable cell among the neighbor cells of the same priority, the method may include determining cells having a lower priority than the serving cell.

The cell reselection method may further include reselecting one of the neighbor cells of the same priority when there is a suitable cell among the neighbor cells of the same priority.

In the determining of the suitable cell, it may be determined whether the measured value of the neighboring cells of the same priority is larger than a preset threshold.

The preset threshold may be a value of a THRES_serving_low parameter.

When there is no suitable cell among the neighbor cells of the same priority, when there is no suitable non-serving GSM cell, when the measurement value of all GSM cells is smaller than the preset threshold value, or when the value of the THRES_serving_low parameter This may be the case when the measured values of all GSM cells are small.

The measured value of the serving cell may be defined as an S_serving parameter.

In the determining of the low priority cells, it may be determined whether the measured value of the low priority cells is larger than a preset threshold.

The serving cell may be a GSM cell.

The neighbor cells of the same priority may be neighbor cells by a radio access technology having the same priority as the serving cell or neighbor cells using frequencies having the same priority as the serving cell.

The low priority neighbor cell may be a neighbor cell using a radio access technology having a lower priority than the radio access technology of the serving cell, or a neighbor cell using a frequency having a lower priority than the frequency of the serving cell.

 On the other hand, in order to achieve the above object, the present invention provides a terminal. The terminal comprises a storage means; And a processor, wherein the processor determines whether a measurement value for a serving cell is lower than a threshold value, and if lower than the threshold value, neighboring cells having the same priority as the serving cell. ), And if there is no suitable cell among the neighboring cells of the same priority, the process of determining the cells of a lower priority than the serving cell may be performed.

According to the present invention, if a measurement value (i.e., power strength, RSRP, SNR) for a neighbor cell, for example, an E-UTRAN cell, by a high-priority radio access technology is greater than an upper limit threshold, the terminal has the higher priority. It is possible to reselect neighboring cells by the rank radio access technology.

Further, when the high priority cell is smaller than the upper limit threshold, the terminal may reselect the cell of the same priority if there is a suitable cell among cells of the same priority. In addition, if there is no suitable cell among the cells of the same priority, the terminal may reselect a cell having a lower priority.

As described above, according to the present invention, the terminal can efficiently select a suitable cell from among cells of a high priority radio access technology, cells of the same priority radio access technology, and cells of a low priority radio access technology.

It is to be noted that the technical terms used herein are merely used to describe particular embodiments, and are not intended to limit the present invention. In addition, the technical terms used in the present specification should be interpreted as meanings generally understood by those skilled in the art unless excessively defined otherwise in the present specification, and excessively It should not be interpreted in a comprehensive sense or in an overly reduced sense. In addition, when the technical terms used herein are incorrect technical terms that do not accurately express the spirit of the present invention, they should be replaced with technical terms that can be understood correctly by those skilled in the art. In addition, the general terms used in the present invention should be interpreted as defined in the dictionary or according to the context before and after, and should not be interpreted in an excessively reduced sense.

Also, the singular forms "as used herein include plural referents unless the context clearly dictates otherwise. In this application, terms such as “consisting of” or “having” should not be construed as necessarily including all of the various components, or various steps described in the specification, some of which include some or some of the steps. It should be construed that it may not be, or may further include additional components or steps.

In addition, terms including ordinal numbers, such as first and second, as used herein may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

When a component is said to be "connected" or "connected" to another component, it may be directly connected or connected to that other component, but there may be other components in between. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

Hereinafter, a terminal (terminal) is mentioned, but may be referred to as a mobile station (MS), a user equipment (UE) of UMTS or a mobile station (MS) of GSM, and such a terminal may be a mobile terminal, a mobile phone, a cellular phone, a PDA ( It may be mobile, such as Personal Digital Assistants, smart phones, laptop computers, or it may not be mobile, such as a personal computer or a vehicle-mounted device.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, and the same or similar components will be given the same reference numerals regardless of the reference numerals, and redundant description thereof will be omitted. In addition, in describing the present invention, when it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, it should be noted that the accompanying drawings are only for easily understanding the spirit of the present invention and should not be construed as limiting the spirit of the present invention by the accompanying drawings. The spirit of the present invention should be construed to extend to all changes, equivalents, and substitutes in addition to the accompanying drawings.

1 is a flowchart illustrating a cell reselection method according to a first embodiment of the present invention, which will be described with reference to FIG. 1 as follows.

First, the UE measures a serving cell (S111), and if the serving cell does not have the highest priority (S112) and there is a neighboring cell having a higher priority than the serving cell (S113), Neighbor cells are measured (S114).

A radio access technology (RAT) of higher priority than the serving cell or a neighboring cell by a high priority frequency is called a "high priority neighbor cell."

In this case, the measurement may be a strength of a received signal, that is, a measurement of power and a measurement of SNR. The serving cell and the cell by the same priority radio access technology may refer to a cell belonging to a GSM EDGE Radio Access Network (GERAN). The cell according to the high priority radio access technology may refer to a cell of an Evolved-UTRAN (E-UTRAN).

The measured value for the serving cell is defined as an S_serving parameter, and the S_serving parameter is defined as C1, which is a path loss criterion parameter, and C1 is again defined as follows.

C1 = (A Max (B, 0))

here,

A = RLA_C-RXLEV_ACCESS_MIN

B = MS_TXPWR_MAX_CCH-P

The RXLEV_ACCESS_MIN means a minimum received signal level required for the terminal to access the system. And, MS_TXPWR_MAX_CCH means the maximum transmit power level used by the terminal when connecting to the system. P denotes a maximum RF output power of the MS.

The measured value for the neighbor cell is defined by the S_non_serving_XXX parameter, and the S_non_serving_XXX parameter means the measurement quality of the neighbor cell of a radio access technology other than the radio access technology to which the serving cell belongs. In this case, XXX refers to a radio access technology (RAT), XXX may have a higher priority, lower priority or the same priority than the serving cell.

Subsequently, the terminal determines whether the measured values of the neighbor cells of the high priority are larger than an upper limit threshold (S115). The upper threshold value is defined by the THRESH_xxx_high parameter, and the THRESH_xxx_high parameter is an upper threshold value for the measurement value required for reselection to the high priority neighbor cell.

As a result of the determination, when there are neighbor cells larger than the upper limit threshold value, the neighboring cells having a higher priority than the upper limit threshold value are reselected (S116).

Meanwhile, when there is no neighbor cell having a higher priority than the serving cell (S113), the measured value of the serving cell is smaller than the first lower limit threshold value THRESH_serving_low and the measured value of the neighboring cell having the same rank. It is determined whether or not (S117).

When the measured value of the serving cell is smaller than the first lower limit threshold value THRESH_serving_low and the measured value of the neighboring cell having the same rank, the value of the neighboring cell is compared with the second lower limit threshold value THRESH_XXX_low, It is determined whether there is a neighboring cell having a lower priority than the lower limit threshold 2 (S118). The THRESH_XXX_low value may be larger or smaller than THRESH_serving_low.

The first lower limit threshold applied to the serving cell is defined in the THRESH_serving_low parameter.

The second lower limit threshold applied to the neighbor cell is defined in the THRESH_XXX_low parameter, and the THRESH_XXX_low parameter is a threshold value for the neighbor cell to which the UE can reselect to a cell of lower priority.

If the measured value of the neighbor cell of the lower priority is greater than the second lower limit threshold THRESH_XXX_low, the neighbor cell of the lower priority having the measured value greater than the second lower limit threshold is reselected (S117).

A neighbor cell with a low priority radio access technology or a low priority frequency is called a 'low priority neighbor cell'.

As described above, according to the first embodiment of the present invention, the terminal has a measured value (that is, power strength, RSRP, SNR) for a high priority cell, for example, an E-UTRAN cell. If greater, the higher priority cell may be reselected. However, when the measured value of the serving cell is smaller than the lower limit threshold, the cell may be reselected to a lower priority cell.

Hereinafter, examples of reselecting a cell will be described with reference to FIGS. 2 to 5.

2 shows an example in which the method shown in FIG. 1 is applied.

First, referring to FIG. 2, the measured value of the serving cell, for example S_serving, is lower than the first lower limit threshold, that is, THRESH_serving_low, and neighbor cells of the same priority, for example, GERAN cells (cells 3, 4,... , n) is lower than the measured value (S117). In addition, the measured value of the neighboring cells (cells 1 and 2 shown) of lower priority is larger than the second lower limit threshold (S118). Accordingly, the terminal reselects the low priority neighbor cells (cells 1 and 2 shown) (S119). The THRESH_XXX_low value may be larger or smaller than THRESH_serving_low.

3 illustrates another example in which the method illustrated in FIG. 1 is applied, and FIG. 4 illustrates another example in which the method illustrated in FIG. 1 is applied.

Referring to FIG. 3, the measured value of the serving cell, such as S_serving, is lower than the first lower limit threshold, that is, THRESH_serving_low, and neighbor cells of the same priority, such as GERAN cells (cells 3, 4,... It is lower than the measured value of n) (S117). Next, the measured value of the lower priority neighboring cells (cells 1 and 2 shown) is greater than the second lower limit threshold (S118). Accordingly, the terminal reselects the low priority neighbor cells (cells 1 and 2 shown) (S119).

Meanwhile, referring to FIG. 4, the measured value of the serving cell, for example, S_serving, is lower than the first lower limit threshold value, that is, THRESH_serving_low, and neighbor cells of the same priority, for example, GERAN cells (cells 3, 4,. , n) is lower than the measured value of (S117). Next, the measured value of the lower priority neighboring cells (cells 1 and 2 shown) is greater than the second lower limit threshold (S118). Accordingly, the terminal reselects the low priority neighbor cells (cells 1 and 2 shown) (S119). The value of THRESH_XXX_low in FIGS. 3 and 4 may be larger or smaller than THRESH_serving_low.

As described above, the terminal may reselect a lower priority cell.

However, in the case of FIGS. 3 and 4, among the cells of the same priority, there are cells having a value larger than the lower limit threshold. Therefore, it may be more preferable that the terminal selects cells of the same priority, not the cells of the lower priority. The first embodiment described above has several advantages, but has such disadvantages.

5 shows another example to which the method shown in FIG. 1 is applied.

The THRESH_XXX_low value may be larger or smaller than THRESH_serving_low. As can be seen with reference to FIG. 5, the measured value of the serving cell, eg, the value of the S_serving parameter, is lower than the first lower limit threshold, that is, THRESH_serving_low. However, the measured value of the serving cell, for example, the value of the S_serving parameter, is higher than the measured value of the neighboring cell of the same priority, for example, the GERAN cell (cells 3, 4, ..., n shown) (S117). Therefore, the terminal does not perform cell reselection.

However, as shown, since the measured value of the low priority cell is higher than the lower limit threshold, it may be desirable to reselect the low priority cell.

As described above, according to the first embodiment, there are various advantages, but as mentioned, the case where the measured value of the serving cell is larger than the measured value of the cells of the same priority is not considered. Accordingly, the present specification also proposes a second embodiment as follows.

6 is a flowchart illustrating a cell reselection method according to a second embodiment of the present invention.

As can be seen with reference to FIG. 6, according to the second embodiment of the present invention, if there is a cell having a value greater than a lower limit threshold among cells of the same priority as the serving cell, the cells of the same priority may be reselected. do.

In addition, in the second embodiment of the present invention, if the measured value of the serving cell is larger than the measured value of the cell of the same priority, if there is a low priority cell having a measured value larger than the lower limit threshold, the low Allows reselection of cells of priority.

In addition, according to the second embodiment of the present invention, when the measured value of the serving cell is larger than the measured value of the cells of the same priority and smaller than the first lower limit threshold THRESH_serving_low, the measurement is larger than the second lower limit threshold THRESH_XXX_low. If there is a low priority neighbor cell with a value, it is possible to reselect to the low priority neighbor cell. The THRESH_XXX_low value may be larger or smaller than THRESH_serving_low.

A description with reference to FIG. 6 is as follows.

First, the terminal measures a serving cell (S211). If the serving cell does not have the highest priority (S212) and there is a neighboring cell having a higher priority than the serving cell (S213), the neighboring cells of the high priority are measured (S214). The terminal determines whether the measured values of the neighbor cells of the high priority are greater than an upper threshold value (eg, THRESH_xxx_high parameter) (S215).

As a result of the determination, when there are neighbor cells larger than the upper limit threshold value, the neighboring cells having a higher priority than the upper limit threshold value are reselected (S216).

On the other hand, when there is no neighbor cell having a higher priority than the serving cell (S213), the UE has a measured value of the serving cell smaller than a first lower limit threshold value (eg, the value of the THRESH_serving_low parameter), It is determined whether there is no neighboring priority cell suitable for selection (S217). The measured value of the serving cell is smaller than the first lower limit threshold value, and there is no neighboring cell of the same priority suitable for reselection. In this case, it is determined whether there is a neighboring cell having a lower priority and having a value greater than a second lower limit threshold (eg, the value of the THRESH_XXX_low parameter) (S218). When there is no neighbor cell having a value greater than the second lower limit threshold, it is determined whether there is a neighbor cell whose measurement value of the neighbor cell is larger than a serving cell, for example, H_PRIO or more, and the measurement value of the neighbor cell is Reselect cells larger than H_PRIO above the serving cell in order.

However, when there is a neighbor cell having a value larger than the second lower limit threshold, the neighboring cell having the lower priority and larger than the second lower limit threshold (eg, the value of the THRESH_XXX_low parameter) is selected (S219). Herein, a suitable cell means a cell of the same priority having a value larger than a predefined threshold. In other words, the measured value of the same priority neighboring cell should not be smaller than the predefined threshold. The predefined threshold may be the lower threshold (eg, the value of the THRESH_serving_low parameter). That is, the measured value of the same priority neighbor cell should not be smaller than the lower limit threshold value (eg, the value of the THRESH_serving_low parameter). In order to improve understanding, it is expressed in various ways as follows.

There are no suitable non-serving GSM cells for reselection. Or, there are no suitable non-serving GSM cells for reselection among all measured cells. Or, there are no suitable non-serving GSM cells. Or, all measured GSM cells are lower than a threshold of GSM cell suitability. Or, all measured non-serving GSM cells are lower than a threshold of GSM cell suitability. Or, all measured GSM cells are lower than a threshold of GSM cell suitability.

Or, in order to understand the process S217 and S219, if expressed in English is as follows.

If the values of S_serving and all measured GSM cells are lower than THRESH_serving_low for the serving cell. Alternatively, if the values of S_serving and all measured non-serving GSM cells are lower than THRESH_serving_low for the serving cell. Alternatively, if all measured GSM cells including the values of S_serving are lower than THRESH_serving_low for the serving cell.

For the purpose of understanding the above, it is as follows when expressed in English.

The value of S_serving is lower than THRESH_serving_low for the serving cell, and there are no suitable non-serving GSM cells for reselection. The value of S_serving is lower than THRESH_serving_low for the serving cell, and there are no suitable non-serving GSM cells for reselection among all measured cells. The value of S_serving is lower than THRESH_serving_low for the serving cell, and there are no suitable non-serving GSM cells. The value of S_serving is lower than THRESH_serving_low for the serving cell, and all measured GSM cells are lower than a threshold of GSM cell suitability. The value of S_serving is lower than THRESH_serving_low for the serving cell, and all measured non-serving GSM cells are lower than a threshold of GSM cell suitability. The values of S_serving and all measured GSM cells are lower than a threshold of GSM cell suitability. The values of S_serving and all measured non-serving GSM cells are lower than a threshold of GSM cell suitability. The values of S_serving and all measured GSM cells are lower than THRESH_serving_low for the serving cell. The values of S_serving and all measured non-serving GSM cells are lower than THRESH_serving_low for the serving cell. All measured GSM cells including the values of S_serving are lower than THRESH_serving_low for the serving cell.

As described above, according to the second embodiment of the present invention, the UE has a measured value (ie power strength, RSRP, SNR) for a high priority cell, for example, an E-UTRAN cell, with the upper limit threshold. If greater, the higher priority cell may be reselected.

As described above, according to the second embodiment of the present invention, a terminal selects a suitable cell from among cells of a high priority radio access technology, cells of the same priority radio access technology, and cells of a low priority radio access technology. You can choose efficiently.

The method presented in the present invention can be modified as shown in FIG.

That is, when the measured value of the serving cell is smaller than the first lower limit threshold and there are neighboring cells of the same priority suitable for reselection (S215), the neighboring cell having a value larger than the second lower limit threshold is determined. If not, it is possible to determine whether there is a neighbor cell whose measured value of the neighbor cell is larger than a serving cell, for example, H_PRIO or more, and reselect cells in which the measured value of the neighbor cell is H_PRIO or larger than the serving cell in order. .

The method according to the invention described thus far can be implemented in software, hardware, or a combination thereof. For example, the method according to the present invention may be implemented as codes or instructions in a software program that may be executed by a processor of the terminal (eg, the terminal internal microprocessor), and a storage medium (eg , An internal memory of the terminal, a flash memory, a hard disk, and the like.

Hardware implementation of the terminal can be achieved through a transceiver (not shown), a storage means (not shown), a controller (not shown). Such an implementation will not be described in detail as will be readily understood by those skilled in the art with reference to FIGS. 1 to 6.

In the above described exemplary embodiments of the present invention by way of example, but the scope of the present invention is not limited to these specific embodiments, the present invention is in various forms within the scope of the spirit and claims of the present invention Can be modified, changed, or improved.

1 is a flowchart illustrating a cell reselection method according to a first embodiment of the present invention.

2 shows an example in which the method shown in FIG. 1 is applied.

3 shows another example in which the method shown in FIG. 1 is applied.

4 shows another example in which the method illustrated in FIG. 1 is applied.

5 shows another example to which the method shown in FIG. 1 is applied.

6 is a flowchart illustrating a cell reselection method according to a second embodiment of the present invention.

7 is a flowchart illustrating a modification of the cell reselection method according to the second embodiment of the present invention.

Claims (15)

Determining whether a measurement value for a serving cell is lower than a threshold value; Determining whether there is a suitable cell among neighboring cells having the same priority as the serving cell when the threshold value is lower than the threshold; And if there is no suitable cell among the neighbor cells of the same priority, determining for cells of lower priority than the serving cell. The method of claim 1, If there is a suitable cell among the neighbor cells of the same priority, And reselecting one of the neighbor cells of the same priority. The method of claim 1, wherein the determining of the appropriate cell And determining whether the measured value of the neighboring cells of the same priority is greater than a preset threshold. The method of claim 3, wherein the preset threshold is A cell reselection method, characterized in that the value of the THRES_serving_low parameter. The method of claim 1, wherein when there is no suitable cell among neighbor cells of the same priority, If there is no suitable non-serving GSM cell, All GSM cells have a measured value less than the preset threshold, or A cell reselection method, characterized in that the measurement value of all GSM cells is smaller than the value of the THRES_serving_low parameter. The method of claim 1, wherein the measured value of the serving cell is Cell reselection method characterized in that it is defined by the S_serving parameter. The method of claim 1, wherein the determining of the low priority cells And determining whether the measured value of the cells of the lower priority is greater than a preset threshold. The method of claim 1, wherein the neighbor cells of the same priority are Neighbor cells by radio access technology of the same priority as the serving cell, or And a neighboring cell using a frequency having the same priority as that of the serving cell. The method of claim 1, wherein the low priority neighbor cell is Neighbor cells by a radio access technology of a lower priority than the radio access technology of the serving cell, or And a neighboring cell using a frequency having a lower priority than a frequency of the serving cell. The method of claim 1, wherein the serving cell Cell reselection method characterized in that the GSM cell. A transceiver; Storage means; And And a processor, wherein the processor determines whether a measurement value for a serving cell is lower than a threshold value, and if lower than the threshold value, neighboring cells having the same priority as the serving cell. Determining whether there is a suitable cell during the operation, and when there is no suitable cell among the neighboring cells of the same priority, determining a cell having a lower priority than the serving cell. 12. The method of claim 11, wherein the determination of the suitable cell And the processor determines whether the measured value of the neighboring cell of the same priority is larger than a preset threshold. The method of claim 12, wherein the preset threshold is A cell reselection method, characterized in that the value of the THRES_serving_low parameter. 12. The method of claim 11, wherein when there are no suitable cells among the neighbor cells of the same priority, If there is no suitable non-serving GSM cell, All GSM cells have a measured value less than the preset threshold, or A terminal characterized in that the measured value of all GSM cells is smaller than the value of the THRES_serving_low parameter. The method of claim 11, wherein the measured value of the serving cell is Terminal characterized in that defined by the S_serving parameter.

Images