TWI566612B - Method of cell reselection - Google Patents

Description

Cell reselection method

The present invention refers to a method of cell reselection, and more particularly to a method of adjusting the priority of a cell reselection procedure by supporting a device to support device communication.

In a cellular wireless communication system, a communication device communicates with another communication device through a base station, that is, the base station can act as a relay entity between communication devices. However, such communication methods are inefficient in terms of coverage area, resource usage, and transmission delay, particularly where each communication device is close to each other and can communicate with each other. Therefore, the industry proposes Device-to-Device (D2D) communication, that is, two adjacent communication devices can directly communicate with each other (such as transmitting/receiving packets) without transposing packets through the base station. In order to improve the coverage area, resource usage and/or transmission delay of the base station.

According to Section 9.1.2 of the 3rd Generation Partnership Project (3GPP) standard TS 36.843, the device-to-device communication may adopt the first mode (mode 1) dominated by the network or the second mode dominated by the user. Mode (mode 2) for resource allocation. In the first mode, when the two communication devices are in coverage of the base station and the device-to-device communication is to be performed, the base station allocates the required resources to the two communication devices. However, the coverage area of the first mode is limited and cannot be applied to the case where the communication device is out-of-coverage at the base station. In the second mode, when the two communication devices want to perform device-to-device communication, a specific resource is selected from the resource pool for data transmission. Therefore, the second mode can be applied to the coverage of the communication device at the base station. Out of scope or in In the case of an edge-of-coverage, and the communication device entering the idle mode mainly uses the second mode.

However, under the conventional device-to-device communication architecture, the communication device cannot know whether the network side supports the device-to-device communication, or even whether the network end supports the device-to-device communication first mode or the second mode. Moreover, the size value of the cell reselection priority (CellReselection Priority) parameter of TS 36.331 is independent of whether the network side supports device-to-device communication, the first mode or the second mode, so the corresponding cell reselects the priority parameter as the highest priority neighboring cell or The frequency does not necessarily support device-to-device communication. After the communication device performs cell reselection according to the cells selected by the network to reselect the priority parameters, the communication device may reselect the neighboring cells that do not support the device to communicate with the device, and interrupt the device-to-device communication that was already in progress. Under this circumstance, how to improve the way of cell re-selection has become one of the goals of the industry.

Accordingly, the present invention primarily provides a method of cell reselection that adjusts the priority of the cell reselection procedure in response to device-to-device communication support.

The invention discloses a cell reselection method, which is used in a communication device of a communication system, which comprises receiving a device-to-device (D2D) communication information and a broadcast of a network end of the communication system. First sorting information; and when the communication device is in an operating situation, re-listing a second sorting information according to the device communicating information to the device.

The invention further discloses a cell reselection method for a network end of a communication system, comprising: a device-to-device (D2D) communication information and a first sorting information; wherein, when In one operation mode, the communication device re-lists a second sorting information according to the device communication information.

10‧‧‧Communication system

UE1, UE2‧‧‧ communication device

ND‧‧‧ network side

RAN1, RAN2‧‧‧ communication network

100, 110, 120, 130‧‧‧ base stations

100c, 110c, 120c, 130c‧‧‧ service cells

CN‧‧‧core network

20‧‧‧ device

200‧‧‧Processing device

210‧‧‧ storage unit

214‧‧‧ Code

220‧‧‧Communication interface unit

30, 40‧‧‧ Process

300~322, 400~422‧‧‧ steps

FIG. 1 is a schematic diagram of a communication system according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of an apparatus according to an embodiment of the present invention.

3 and 4 are flow charts of a process of an embodiment of the present invention.

5 and 6 are flowcharts of a process of an embodiment of the present invention.

FIG. 1 is a schematic diagram of a communication system 10 according to an embodiment of the present invention. The communication system 10 is a cellular wireless communication system, which can be represented by a network terminal ND and communication devices UE1, UE2. The network ND may include communication networks RAN1 and RAN2, and the communication networks RAN1 and RAN2 respectively include base stations 100, 110, 120, and 130. The base stations 100 to 130 respectively serve the cells 100c and 110c. 120c, 130c, but not limited to this, a base station can also serve multiple cells depending on the system design. In an embodiment, the communication network RAN1, RAN2 may be a Universal Terrestrial Radio Access Network (UTRAN) in a Universal Mobile Telecommunications System (UMTS), and the base stations 100-130 Correspondingly, it is a base station (Node-B, NB). In another embodiment, the communication networks RAN1, RAN2 may be in an advanced version of a Long Term Evolution (LTE) system, an Advanced Long Term Evolution (LTE-A) system, or an Advanced Long Term Evolution system. An evolved universal terrestrial radio access network (evolved UTRAN, E-UTRAN), and the base stations 100-130 are correspondingly evolved-eNBs (evolved-NBs, eNBs). In another embodiment, the communication networks RAN1, RAN2 may be wireless communication networks conforming to wireless communication standards such as IEEE 802.11 and IEEE 802.16.

Further, the network end ND can also include the communication network RAN1, RAN2 And a core network CN, wherein the core network CN includes, for example, a Mobility Management Entity (MME), a Serving Gateway (S-GW), and a Packet Data Network (PDN) channel. A network entity such as a Self-Organizing Networks (SON) server and/or a Radio Network Controller (RNC). In other words, after the network ND receives the information transmitted by a communication device, the information can only be processed by the communication network RAN1, RAN2, and the decision corresponding to the information is also performed by the communication networks RAN1, RAN2. . On the other hand, the communication networks RAN1, RAN2 can forward the information to the core network CN, and after the core network CN processes the information, the decision corresponding to the information can be performed by the core network CN. Furthermore, the information can be processed simultaneously by the communication networks RAN1, RAN2 and the core network CN, and the communication networks RAN1, RAN2 and the core network CN can coordinate and/or cooperate with one another to perform decisions relating to the information. The communication devices UE1 and UE2 can be a User Equipment (UE), a Machine Type Communication (MTC) device, a mobile phone, a notebook computer, a tablet computer, an e-book or a Portable computer system. In addition, according to the data transmission direction, the network terminal ND and the communication devices UE1 and UR2 can be regarded as a transmitting end or a receiving end respectively. For example, for an uplink (UL), the communication devices UE1 and UE2 are The transmitting end and the network end ND are the receiving end. For the downlink (DL), the network end ND is the transmitting end and the communication devices UE1 and UE2 are the receiving end.

FIG. 2 is a schematic diagram of a device 20 according to an embodiment of the present invention. The device 20 may be a device of the communication device UE1, UE2 or the network terminal ND shown in FIG. 1, but is not limited thereto. The device 20 can include a processing device 200, a storage unit 210, and a communication interface unit 220. The processing device 200 can be a microprocessor or an Application Specific Integrated Circuit (ASIC). The storage unit 210 can be any data storage device for storing a code 214. The processing device 200 can read and execute the code 214 through the storage unit 210. For example, the storage unit 210 includes, but is not limited to, a Subscriber Identity Module (Subscriber Identity Module, SIM), Read-Only Memory (ROM), Flash Memory, Random-Access Memory (RAM), CD-ROM (CD-ROM/DVD) -ROM), Magnetic Tape, Hard Disk, and Optical Data Storage Device. The communication interface unit 220 can be a wireless transceiver that can transmit and receive signals (such as messages or packets, etc.) according to the processing result of the processing device 200.

3 and 4 are flow charts of a process 30 according to an embodiment of the present invention. The process 30 can be used in the communication device UE1 in Fig. 1 for cell reselection. Flow 30 can be compiled into code 214, which includes the following steps:

Step 300: Start.

Step 302: The communication device UE1 receives a device-to-device (D2D) communication information and a first sorting information broadcasted by the network ND. Wherein, the device-to-device communication information relates to whether a plurality of neighboring cells or a plurality of frequencies of the network terminal ND support a device-to-device communication.

Step 304: When the communication device UE1 is in an operating situation, the communication device UE1 re-lists a second sorting information according to the device-to-device communication information. Wherein, a plurality of adjacent cells or a plurality of frequencies support the device to communicate with neighboring cells or frequencies of the device before the neighboring cells or frequencies that do not support device-to-device communication.

Step 306: Select, according to the second sorting information, at least one candidate frequency cell corresponding to at least one candidate neighboring cell or frequency ranked in the plurality of neighboring cells or a plurality of frequencies, and determine at least one candidate neighboring cell or at least The ordering relationship between a candidate frequency cell and the serving cell 100c.

Step 308: Perform a first cell reselection criterion when determining that the order of the at least one candidate neighboring cell or the at least one candidate frequency cell is the same as the order of the serving cell 100c according to the second sorting information.

Step 310: Perform an R criteria ranking according to a first calculation result of the serving cell and at least one second calculation result of the at least one candidate neighboring cell or the at least one candidate frequency cell.

Step 312: Sorting according to the R criterion, the communication device UE1 selects at least one candidate neighboring cell or a cell with the highest priority among the at least one candidate frequency cell.

Step 314: Perform a second cell reselection criterion when the ranking of the at least one candidate neighboring cell or the at least one candidate frequency cell is different from the ordering of the serving cell 100c according to the second sorting information.

Step 316: When the ordering of at least one candidate neighboring cell or at least one candidate frequency cell is prioritized over the ordering of the serving cell 100c, and when at least one candidate neighboring cell or at least one candidate frequency cell has at least one first measurement result at a time When the interval Treselection _RAT is greater than a first reference value, the communication device UE1 selectively selects one cell among at least one candidate neighboring cell or at least one candidate frequency cell according to at least one second calculation result.

Step 318: When the order of at least one candidate neighboring cell or at least one candidate frequency cell lags behind the order of the serving cell 100c, and when a second measurement result of the serving cell 100c is less than a second in the time interval Treselection _RAT When the reference value is, and when the first measurement result of the at least one candidate neighboring cell or the at least one candidate frequency cell is greater than a third reference value in the time interval Treselection _RAT , the communication device UE1 selectively selects according to at least one second calculation result. Selecting one cell from at least one candidate neighboring cell or at least one candidate frequency cell.

Step 320: Perform cell reselection to the selected cells.

Step 322: End.

In detail, in accordance with step 302, the communication device UE1 resides in a serving cell (e.g., cell 100c) and can receive system information broadcast by the serving cell 100c, and the cells 110c-130c are neighboring cells serving the cell 100c. The system information includes a device-to-device communication information and a first sorting information, which can pass through a third type system information block (System) Information Block Type 3, SIB3), Type 5 System Information Block (SIB5), Type 6 System Information Block (SIB6), Type 7 System Information Block (SIB7), Type 8 System Information Block (SIB8) Or a radio resource control (RRC) connection release (radio resources control (RRC) connection release) transmission. The first sorting information is used to indicate the priority order of a plurality of neighboring cells or a plurality of frequencies in the cell reselection procedure of the network ND, and includes a plurality of first cell reselection priority (CellReselectionPriority) parameters. Each first cell reselection priority parameter is an integer value between 0 and 7 according to the 3rd Generation Partnership Project (3GPP) standard TS 36.331, wherein 7 corresponds to the highest priority order. Wherein, the plurality of adjacent cell lines represent cells of the same frequency as the serving cell 100c (eg, cell 110c), the plurality of frequencies represent frequencies different from the serving cell 100c (eg, the frequency corresponding to the cell 120c) or cross-system wireless access technology The frequency of (inter Radio Access Technology, inter-RAT) (such as the frequency corresponding to cell 130c). In addition, the device-to-device communication information relates to a plurality of neighboring cells (e.g., cell 110c) or a plurality of frequencies (e.g., frequencies corresponding to cells 120c, 130c) associated with the network ND supporting a device-to-device communication. For example, Table 1 lists possible content of system information, which may include an Absolute Radio Frequency Channel Number (ARFCN) and information on whether device-to-device communication is supported (ie, device-to-device communication information). Wherein, an absolute wireless channel number corresponds to a specific uplink frequency and a specific downlink frequency, and corresponding to the absolute wireless channel number of the serving cell 100c, the system information further includes a cell ID (Cell ID), for example, The cell identification code of the adjacent cell 110c having the same frequency as the serving cell 100c may be one of 1 to 4.

In other words, since the communication device UE1 can receive the device-to-device communication information broadcasted by the network ND, the communication device UE1 can know the support situation of the plurality of adjacent cells or a plurality of frequencies for device-to-device communication.

Then, according to step 304, when the communication device UE1 is in an operating situation, the communication device UE1 adjusts the received first sorting information to the second sorting information according to the device-to-device communication information. The operation situation is that the communication device UE1 performs a device-to-device communication program in an idle mode; or, the operation situation is that the communication device UE1 is in a idle mode to perform a device-to-device communication program; or, the operation situation is a communication device. The UE 1 intends to perform a device-to-device communication procedure to transmit a device-to-device communication indication (ProSe interest indication) to the network terminal ND, but the network terminal ND does not respond, and causes the communication device UE1 to leave a connected mode. Moreover, the second sorting information also includes a plurality of second cell reselection priority parameters, and the highest priority order corresponds to the largest value. In the second sorting information, a plurality of neighboring cells or a plurality of frequencies support the device to communicate with neighboring cells or frequencies of the device before the neighboring cells or frequencies that do not support the device to communicate with the device, that is, the supporting device communicates with the device. The second cell, which has a larger adjacent cell or frequency, reselects the priority parameter. For example, please refer to Table 1 and Table 2, wherein Tables 1 and 2 respectively list the first cell reselection priority parameter and the second cell reselection priority parameter corresponding to the absolute wireless channel number before and after reordering according to step 304. The situation. As shown in Table 1, before reordering in step 304, the first cell reselection priority parameters correspond to different absolutes. The wireless channel number is a different integer value, and as shown in Table 2, after the reordering in step 304, the second cell reselection priority parameter is adjusted corresponding to different absolute wireless channel numbers and whether the device supports device communication information. The first cell reselects the value of the priority parameter. For example, although the corresponding frequency of the absolute wireless channel number 1650 has a preferential first cell reselection priority parameter (integer value 6), since it does not support device-to-device communication, its second cell reselection priority parameter is sorted backwards to The integer value is 3. In addition, cells having a cell ID of 1 to 4 have the same absolute radio channel number 1600, but have different second cell reselection priority parameters because the supporting device has different communication conditions for the device, that is, even adjacent cells 110c is the same frequency as serving cell 100c, and the priority order of the two may be different in the cell reselection procedure.

In other words, since the communication device UE1 re-lists the second sorting information according to the device-to-device communication information, so that a plurality of neighboring cells or a plurality of frequencies support the device to sort adjacent cells or frequencies of the device communication to the unsupported device. Before the neighboring cells or frequencies of the device communication, the communication device UE1 can perform cell reselection according to the support situation of the device-to-device communication according to a plurality of neighboring cells or a plurality of frequencies, and relatively prefer the support device to the device communication neighbor. Near cell or frequency.

Next, in step 306, according to the second sorting information, at least one candidate neighboring cell (such as cell 110c) or at least one candidate frequency cell corresponding to the frequency is selected among the plurality of neighboring cells or a plurality of frequencies ( For example, the cells 120c or 130c), and determine the ordering relationship of at least one candidate neighboring cell or at least one candidate frequency cell to the serving cell 100c. According to FIG. 5, the cells whose cell identification codes are 2 and 3 are selected first in step 306.

In step 308, when it is determined according to the second sorting information that at least one candidate neighboring cell (such as a cell with a cell ID of 2, 3) or at least one candidate frequency cell is sorted in the same order as the serving cell 100c, performing a A cell reselection criterion. The first cell reselection criteria is similar to the content of Section 5.2.4.6 of the Third Generation Partnership Project Standard TS 36.304, which includes steps 310, 312. In step 310, a R is performed according to a cell-ranking criterion Rs value of the serving cell 100c and a cell-ranking criterion Rn value of at least one candidate neighboring cell or at least one candidate frequency cell. The criteria are ordered, and, in step 312, based on the R criteria, the communication device UE1 selects at least one candidate neighboring cell or at least one candidate frequency cell among the highest ranked cells, and performs cell reselection. Wherein, the R criterion ordering refers to sorting the serving cell sorting standard value and the neighboring cell sorting standard value, that is, the measured value of at least one candidate neighboring cell or at least one candidate frequency cell has to be offset before the serving cell 100c Comparison of measured values.

In step 314, a second cell reselection criterion is performed when it is determined that the ranking of the at least one candidate neighboring cell or the at least one candidate frequency cell is different from the ordering of the serving cell 100c according to the second ranking information. The second cell reselection criteria may be similar to the contents of Section 5.2.4.5 of the Third Generation Partnership Program Standard TS 36.304, which includes steps 316, 318. In step 316, when the ranking of the at least one candidate neighboring cell or the at least one candidate frequency cell is prioritized over the ordering of the serving cell 100c, and the first measurement result of the at least one candidate neighboring cell or the at least one candidate frequency cell is at a time When the interval Treselection _RAT is greater than the first reference value, the communication device UE1 selects at least one candidate neighboring cell or at least one candidate frequency cell among the highest priority ones according to the sorting result of the neighboring cell sorting standard value corresponding to the communication system type. Cells and undergo cell re-selection. In step 318, when the ordering of the at least one candidate neighboring cell or the at least one candidate frequency cell lags behind the ordering of the serving cell 100c, and the second measurement result of the serving cell 100c is less than the second reference in the time interval Treselection _RAT And when the first measurement result of the at least one candidate neighboring cell or the at least one candidate frequency cell is greater than the third reference value in a time interval Treselection _RAT , corresponding to the communication system type and selectively according to the neighboring cell ranking standard value As a result of the sorting, the communication device UE1 selects at least one candidate neighboring cell or at least one cell of the candidate frequency ranks the highest priority cell and performs cell reselection. Wherein, according to the type of the communication system, the first measurement result and the second measurement result may be a cell selection quality (Squal) value indicating the quality of the received signal or a cell re-receiving level indicating the received signal strength (Cell Selection receive level, Srxlev) value, the first reference value may correspond to Thresh _{X, HighQ} value or Thresh _{X, HighP} value, the second reference value corresponds to Thresh _{Serving, LowQ} value, and the third reference value may correspond to Thresh _{X, LowQ} Value or Thresh _{X, LowP} value. In addition, when there is only one candidate neighboring cell or a candidate frequency cell, or when at least one candidate neighboring cell or at least one candidate frequency cell has only one cell, the first measurement result is greater than the first reference value in the time interval Treselection _RAT . Or the third reference value, the communication device UE1 directly selects the cell for cell reselection without sorting corresponding to the adjacent cell sorting standard value.

In other words, when the communication device UE1 re-lists the second sorting information according to the device-to-device communication information, even if the frequency of the neighboring cells and the serving cell 100c is the same, the ordering of the second sorting information may be different. In this case, the first cell reselection criterion of step 308 or the second cell reselection criterion of step 314 is only performed depending on whether the ranking is the same, without additionally considering whether the frequency is consistent with the frequency of the serving cell 100c.

The communication system 10 of Fig. 1, the apparatus 20 of Fig. 2, or the flow 30 of Fig. 3 is an embodiment of the present invention, and those skilled in the art can make various modifications without limitation thereto. For example, to further improve the efficiency of cell reselection, please refer to FIG. 5 and FIG. 6 . FIG. 5 and FIG. 6 are flowcharts of a process 40 according to an embodiment of the present invention. The process 40 can be used in the communication device UE1 in Fig. 1 for cell reselection. The process 40 can be compiled into a code 214 that includes the following steps:

Step 400: Start.

Step 402: The communication device UE1 receives a device-to-device communication information and a first sorting information broadcasted by the network ND. The device-to-device communication information relates to whether the plurality of neighboring cells or the plurality of frequencies of the network ND support the first mode (mode 1) or the second mode (mode 2) of the device-to-device communication.

Step 404: When the communication device UE1 is in an operating situation, the communication device UE1 re-lists a second sorting information according to the device-to-device communication information, wherein only the second mode is supported according to the first mode and the second mode. Reordering is only supported in the first mode and does not support the device to communicate with the device.

Step 406: Select, according to the second sorting information, at least one candidate frequency cell corresponding to at least one candidate neighboring cell or frequency ranked in the plurality of neighboring cells or a plurality of frequencies, and determine at least one candidate neighboring cell or at least The ordering relationship between a candidate frequency cell and the serving cell 100c.

Step 408: Perform a first cell reselection criterion when determining that the order of the at least one candidate neighboring cell or the at least one candidate frequency cell is the same as the order of the serving cell 100c according to the second sorting information.

Step 410: Perform an R criteria ranking according to a first calculation result of the serving cell and at least one second calculation result of the at least one candidate neighboring cell or the at least one candidate frequency cell.

Step 412: Sorting according to the R criterion, the communication device UE1 selects at least one candidate neighboring cell or a cell with the highest priority among the at least one candidate frequency cell.

Step 414: Perform a second cell reselection criterion when the ranking of the at least one candidate neighboring cell or the at least one candidate frequency cell is different from the ordering of the serving cell 100c according to the second ranking information.

Step 416: When the ordering of at least one candidate neighboring cell or at least one candidate frequency cell is prioritized over the ordering of the serving cell 100c, and when at least one candidate neighboring cell or at least one candidate frequency cell has at least one first measurement result at a time When the interval Treselection _RAT is greater than a first reference value, the communication device UE1 selectively selects one cell among at least one candidate neighboring cell or at least one candidate frequency cell according to at least one second calculation result.

Step 418: When the order of at least one candidate neighboring cell or at least one candidate frequency cell lags behind the order of the serving cell 100c, and a second measurement result of the serving cell 100c is less than a second in the time interval Treselection _RAT When the reference value is, and when the first measurement result of the at least one candidate neighboring cell or the at least one candidate frequency cell is greater than a third reference value in the time interval Treselection _RAT , the communication device UE1 selectively selects according to at least one second calculation result. Selecting one cell from at least one candidate neighboring cell or at least one candidate frequency cell.

Step 420: Perform cell reselection to the selected cells.

Step 422: End.

As can be seen from the above, the structure of the process 40 is substantially similar to the process 30. The difference is that, according to step 402, the communication device UE1 residing on the serving cell 100c receives the first sorting information broadcasted by the serving cell 100c and the device-to-device communication. Information, wherein the device-to-device communication information is further related to whether a plurality of neighboring cells (such as cell 110c) or a plurality of frequencies (such as the frequencies corresponding to cells 120c, 130c) of the network ND support the first mode of device-to-device communication. Or the second mode. In this way, the communication device UE1 can know the support situation of a plurality of neighboring cells or a plurality of frequencies for device-to-device communication.

Moreover, according to step 404, when the communication device UE1 is in the operating situation, the communication device UE1 adjusts the received first sorting information to the second sorting information according to the device-to-device communication information. Since the communication device entering the idle mode mainly uses the second mode, in one embodiment, the neighboring cells or frequencies supporting the first mode and the second mode among the plurality of adjacent cells or the plurality of frequencies are ordered to support only the first mode. Before adjacent cells or frequencies, a plurality of adjacent cells or a plurality of frequencies support only neighboring cells of the second mode or the frequency is prior to the neighboring cells or frequencies supporting only the first mode, and a plurality of adjacent cells or a plurality of frequencies Only adjacent cells in the first mode are supported or the frequency is prior to the neighboring cells or frequencies that do not support device-to-device communication. For example, please refer to Table 3 and Table 4, wherein Tables 3 and 4 respectively list the first cell reselection priority parameter and the second cell reselection priority parameter corresponding to the absolute wireless channel number before and after reordering according to step 404. The situation. As shown in Table 3 and Table 4, the first sorting information is rearranged into the second sorting information corresponding to different absolute wireless channel numbers and the situation in which the supporting device communicates with the device. For example, the first cell reselection priority parameter (Table 3) corresponding to the frequency of the absolute radio channel number 1650 is preferred (integer value 6), but since it does not support device-to-device communication, its second cell reselects the priority parameter ( Table 4) Sorts backwards to an integer value of 2. And, according to the second sorting information (ie, the second cell reselection priority parameter is a larger integer value of 5), in step 406, only cells with a cell ID of 2 are first selected, and then step 408 is performed. 412.

However, the invention is not limited thereto. In another embodiment, a plurality of neighboring cells or a plurality of frequencies supporting neighboring cells or frequencies of the first mode and the second mode are sorted before neighboring cells or frequencies supporting only the second mode, and a plurality of adjacent cells or plural Only the neighboring cells of the second mode are supported in the frequency or the frequency is prior to the neighboring cells or frequencies supporting only the first mode, and the neighboring cells of the first mode or the plurality of frequencies support only the neighboring cells of the first mode or the frequency is not supported. Before the device communicates with the adjacent cells or frequencies of the device. For example, please refer to Table 3 and Table 5, In Tables 3 and 5, respectively, the first cell reselection priority parameter and the second cell reselection priority parameter correspond to the absolute wireless channel number before and after reordering according to step 404. As shown in Tables 3 and 5, the first sorting information is rearranged into the second sorting information corresponding to different absolute wireless channel numbers and the situation in which the supporting device communicates with the device. For example, the first cell reselection priority parameter (Table 3) corresponding to the frequency of the absolute radio channel number 1650 is preferred (integer value 6), but since it does not support device-to-device communication, its second cell reselects the priority parameter ( Table 5) Sorts backwards to an integer value of 3. And, according to the second sorting information, only cells with a cell identification code of 2 are first selected in step 406 (ie, the second cell reselects the priority parameter to a larger integer value of 7), and then proceeds to step 414. 416.

In other words, since the communication device UE1 re-lists the second sorting information according to the case of supporting the first mode and the second mode, supporting only the second mode, supporting only the first mode, and not supporting the device communicating with the device, the communication is performed. The device UE1 may be based on a plurality of adjacent cells or a plurality of frequency pairs Cell reselection is performed in the case of device-to-device communication support, and the neighboring cells or frequencies that the support device communicates with the device are relatively preferred.

It should be noted that the manner of rearranging the first sorting information into the second sorting information is not limited to the reordering steps 504, 704, and 804 of the fifth, seventh, and eighth graphs, and may be appropriately adjusted according to different system requirements and design considerations. For example, in the reordering steps 504, 704, 804, the first cell reselection priority parameter of the serving cell 100c is the same as the second cell reselection priority parameter, but in another embodiment, the second cell may be first The maximum value of the cell reselection priority parameter is adjusted to an integer value of 5, and the priority cells are reselected by sequentially arranging the serving cells 100c, other neighboring cells, or other cells of other frequencies. Moreover, in another embodiment, the second cell reselection priority parameter that does not support the device to communicate with neighboring cells or frequencies of the device may be set to zero.

It can be seen from the above that the spirit of the present invention is a cell reselection method for the communication device UE1, wherein the communication device UE1 receives the device-to-device communication information and the first sorting information broadcasted by the network ND, and when the communication device UE1 is In the operating situation, the second sorting information is re-listed according to the device-to-device communication information. Similarly, the cell reselection method of the present invention can also be applied to the network side ND, wherein the network side ND broadcast device communicates information with the device and the first sorting information, and when the communication device UE1 is in the operating situation, the communication device UE1 The second sorting information is re-listed according to the received device-to-device communication information. In addition, the method of reordering the second sorting information is related to the content of the device communication information. That is, when the device-to-device communication information relates to whether a plurality of neighboring cells or a plurality of frequencies support device-to-device communication (step 302), a plurality of neighboring cells or a plurality of frequencies support the device to communicate with neighboring cells of the device or The frequency is prior to the second sorting information prior to the neighboring cells or frequencies that do not support device-to-device communication (step 304). And, when the device-to-device communication information is related to whether the plurality of neighboring cells or the plurality of frequencies support the first mode or the second mode of the device-to-device communication (step 402), supporting the first number of adjacent cells or the plurality of frequencies Mode and second mode, only support the second mode, only support the first mode, not support In the case where the device communicates with the device, the communication device UE1 reorders the first sorting information into the second sorting information (step 404).

In the prior art, the communication device cannot know whether the network side supports the device-to-device communication, or even whether the network end supports the device-to-device communication first mode or the second mode. Moreover, the size value of the first cell reselection priority parameter of the TS 36.331 is independent of whether the network side supports the device communication with the device, the first mode or the second mode, so the first cell corresponding to the first cell is reselected as the highest priority neighboring cell. Or the frequency does not necessarily support device-to-device communication.

In contrast, the network terminal ND of the present invention broadcasts whether the device supports the device communication, or even supports the first mode or the second mode of device-to-device communication, so the communication device UE1 can know the neighboring cell or frequency to the device. Support for device communication. Moreover, according to the support situation of the device to the device communication, the communication device UE1 adjusts the first sorting information including the first cell reselection priority parameter to the second sorting information, so the supporting device compares the neighboring cells or frequencies of the device communication. Priority sorting can increase the efficiency of cell reselection. Correspondingly, the communication device UE1 performs a first cell reselection criterion or a second cell reselection criterion according to whether the sorting is the same to select a cell for cell reselection.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

10‧‧‧Communication system

UE1, UE2‧‧‧ communication device

ND‧‧‧ network side

RAN1, RAN2‧‧‧ communication network

100, 110, 120, 130‧‧‧ base stations

100c, 110c, 120c, 130c‧‧‧ service cells

CN‧‧‧core network

Claims (18)

A cell reselection method for a communication device of a communication system, comprising: receiving a device-to-device (D2D) communication information broadcasted by a network end of the communication system and a first Sorting the information; and when the communication device is in an operating situation, the first sorting information is reclassified into a second sorting information according to the device communication information; wherein, the plurality of neighboring cells in the network end The ordering of the at least one neighboring cell in the second sorting information can be different from the ordering of the other neighboring cells of the plurality of neighboring cells in the second sorting information, and the at least one neighboring cell and the another neighboring cell Operate at the same frequency. The cell reselection method according to claim 1, wherein the device-to-device communication information relates to whether the plurality of adjacent cells or the plurality of frequencies of the network end support a device-to-device communication. The cell reselection method according to claim 2, wherein the second sorting information is re-listed according to the device communication information, and the method includes: supporting the device to the plurality of neighboring cells or the plurality of frequencies The neighboring cells or frequencies of communication are prior to the neighboring cells or frequencies that do not support the device's communication with the device. The cell reselection method according to claim 1, wherein the device-to-device communication information is related to a plurality of neighboring cells of the network or whether the plurality of frequencies support the device-to-device communication in a first mode (mode 1 ) or a second mode (mode 2). The cell reselection method according to claim 4, wherein the second sorting information is re-listed according to the device communication information of the device, including: Sorting the plurality of neighboring cells or adjacent cells or frequencies supporting the first mode and the second mode in the plurality of frequencies before the neighboring cells or frequencies supporting only the first mode; the plurality of neighboring cells or the Among the plurality of frequencies, only the neighboring cells or frequencies of the second mode are supported before the neighboring cells or frequencies supporting only the first mode; and the plurality of neighboring cells or the plurality of frequencies only support the first mode Adjacent cells or frequencies are prior to the neighboring cells or frequencies that do not support the device to communicate with the device. The cell reselection method according to claim 5, wherein the second sorting information is re-listed according to the device communication information, and the first plurality of neighboring cells or the plurality of frequencies are supported in the first mode. And the neighboring cells or frequencies of the second mode are prior to the neighboring cells or frequencies that only support the second mode. The cell reselection method according to claim 1, wherein the operation device is that the communication device performs a device-to-device communication program in an idle mode, or the communication device is to perform a device-to-device in the idle mode. The communication program, or the communication device transmits a device-to-device communication indication to the network, but the network does not respond, and the communication device leaves a connected mode. The cell reselection method according to claim 1, further comprising: selecting, according to the second sorting information, at least one candidate ranked as the highest priority among the plurality of neighboring cells or the plurality of frequencies; Performing a first cell reselection criterion, wherein the first cell reselection criterion includes: according to the serving cell, when the ranking information is determined to determine that the ranking of the at least one candidate is the same as the ordering of a serving cell a first calculation result and at least one second calculation result of the at least one candidate are subjected to an R criteria ranking; Sorting according to the R criterion, the communication device performs cell reselection to a candidate with the highest priority among the at least one candidate; and when determining that the ranking of the at least one candidate is different from the ordering of the serving cells according to the second ranking information Performing a second cell reselection criterion, wherein the second cell reselection criterion includes: when the at least one candidate ranking is prioritized over the ranking of the serving cells, and when the at least one candidate is at least one first measurement If the result is greater than a first reference value in a time interval, the communication device selectively performs cell reselection to one of the at least one candidate according to the at least one second calculation result; and when the at least one candidate Sorting backwards when the serving cell is sorted, and when a second measurement result of the serving cell is less than a second reference value in the time interval, and when the at least one candidate of the first measurement result is When the time interval is greater than a third reference value, the communication device selectively performs cell reselection according to the at least one second calculation result to the One candidate is one less candidate; wherein the communication device resides in the serving cell. The cell reselection method according to claim 8, wherein the time interval is a Treselection _RAT defined by a 3rd Generation Partnership Project (3GPP) standard, the first measurement result and the second measurement result The cell selection quality (Squal) value or the Cell selection receive level (Srxlev) value defined by the third generation partner program standard, which is the third generation partner program. Standard definition of Thresh _{X, HighQ} value or Thresh _{X, HighP} value, which is the Thresh _{Serving, LowQ} value defined by the 3rd Generation Partnership Project Standard, which is defined by the 3rd Generation Partnership Project Standard Thresh _{X, LowQ} value or Thresh _{X, LowP} value, the first calculation result is a cell-ranking criterion Rs value defined by the third generation partner program standard, and the second calculation result is the third The cell-ranking criterion Rn value defined by the partner program standard. A cell reselection method for a network end of a communication system, comprising: a device-to-device (D2D) communication information and a first sorting information; wherein, when the communication system When the communication device is in an operating situation, the communication device reclassifies the first sorting information into a second sorting information according to the device communication information of the device; wherein at least one of the plurality of neighboring cells at the network end The ordering of the neighboring cells in the second sorting information can be different from the ordering of the other neighboring cells of the plurality of neighboring cells in the second sorting information, and the at least one neighboring cell operates with the another neighboring cell The same frequency. The cell reselection method of claim 10, wherein the device-to-device communication information relates to whether the plurality of neighboring cells or the plurality of frequencies of the network end support a device-to-device communication. The cell reselection method of claim 11, wherein the second sorting information is re-listed according to the device communication information of the device, comprising: supporting the device to the plurality of neighboring cells or the plurality of frequencies The neighboring cells or frequencies of communication are prior to the neighboring cells or frequencies that do not support the device's communication with the device. The cell reselection method according to claim 10, wherein the device-to-device communication information is related to a plurality of neighboring cells of the network or whether the plurality of frequencies support the device-to-device communication in a first mode (mode 1 ) or a second mode (mode 2). The cell reselection method according to claim 13, wherein the device communication information is determined according to the device And re-listing the second sorting information, including: sorting the plurality of neighboring cells or neighboring cells or frequencies supporting the first mode and the second mode in the plurality of frequencies to support only the proximity of the first mode Before the cell or frequency; sorting the plurality of adjacent cells or adjacent cells or frequencies of the plurality of frequencies that only support the second mode before the neighboring cells or frequencies supporting only the first mode; and the plurality of adjacent cells Or the neighboring cells or frequencies of the plurality of frequencies that only support the first mode are prior to the neighboring cells or frequencies that do not support the device to communicate with the device. The method of reselecting a cell according to claim 14, wherein the second sorting information is re-listed according to the device communication information, and the first plurality of neighboring cells or the plurality of frequencies are supported in the first mode. And the neighboring cells or frequencies of the second mode are prior to the neighboring cells or frequencies that only support the second mode. The cell reselection method according to claim 10, wherein the operation situation is that the communication device performs a device-to-device communication program in an idle mode, or the communication device is to perform a device-to-device in the idle mode. The communication program, or the communication device transmits a device-to-device communication indication to the network, but the network does not respond, and the communication device leaves a connected mode. The cell reselection method of claim 10, further comprising: selecting, according to the second sorting information, at least one candidate ranked first in the plurality of neighboring cells or the plurality of frequencies; Performing a first cell reselection criterion, wherein the first cell reselection criterion includes: according to the serving cell, when the ranking information is determined to determine that the ranking of the at least one candidate is the same as the ordering of a serving cell a first calculation result and at least one second meter of the at least one candidate Calculating an R criterion; and sorting according to the R criterion, the communication device performs cell reselection to a candidate with the highest priority among the at least one candidate; and determining the basis according to the second ranking information Performing a second cell reselection criterion when the at least one candidate ranking is different from the ordering of the serving cells, wherein the second cell reselection criterion includes: when the ranking of the at least one candidate is prioritized over the ordering of the serving cells, And when the at least one first measurement result of the at least one candidate is greater than a first reference value in a time interval, the communication device selectively performs cell reselection to the at least one according to the at least one second calculation result. One of the candidate candidates; and when the ranking of the at least one candidate lags behind the ordering of the serving cells, and when a second measurement result of the serving cell is less than a second reference value in the time interval, and When the first measurement result of the at least one candidate is greater than a third reference value in the time interval, the communication device selectively selects the at least one Two calculation results for cell reselection to the at least one candidate wherein a candidate; wherein the communication device resides in the serving cell. The cell reselection method according to claim 17, wherein the time interval is a Treselection _RAT defined by a 3rd Generation Partnership Project (3GPP) standard, the first measurement result and the second measurement result The cell selection quality (Squal) value or the Cell selection receive level (Srxlev) value defined by the third generation partner program standard, which is the third generation partner program. Standard definition of Thresh _{X, HighQ} value or Thresh _{X, HighP} value, which is the Thresh _{Serving, LowQ} value defined by the 3rd Generation Partnership Project Standard, which is defined by the 3rd Generation Partnership Project Standard Thresh _{X, LowQ} value or Thresh _{X, LowP} value, the first calculation result is a cell-ranking criterion Rs value defined by the third generation partner program standard, and the second calculation result is the third The cell-ranking criterion Rn value defined by the partner program standard.