WO2013020504A1

WO2013020504A1 - Cell selection method and device in multicarrier communication system

Info

Publication number: WO2013020504A1
Application number: PCT/CN2012/079812
Authority: WO
Inventors: 万璐; 陈中明; 黄亚达
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-08-08
Filing date: 2012-08-08
Publication date: 2013-02-14
Also published as: CN102932880B; CN102932880A

Abstract

Provided are a cell selection method and device in a multicarrier communication system, the method comprising: for a packet comprising only a secondary cell, a UE and/or an eNB select a cell for receiving timing advance (TA) control element and/or a cell for time reference respectively for each packet. The problem in the relevant art is that after a plurality of TA packets are introduced, how the secondary cell in the packet comprising only a secondary cell selects the cell for time reference and/or how to select the cell for receiving TA control element, the present invention solves the problem; the solution is adapted to the requirement for multi-TA and multi-packet in the multicarrier communication system, and provides more accurate TA control for each packet, thus enabling the uplink data of each UE to fall into the receiving time window of the eNB when arriving at the eNB, reducing the loss probability of the uplink data and improving the service performance of the whole system.

Description

TECHNICAL FIELD The present invention relates to the field of communications, and in particular to a cell selection method and apparatus in a multi-carrier communication system. BACKGROUND OF THE INVENTION Long Term Evolution Advance (LTE-Advanced) introduces many new technologies to meet the basic needs of IMT-Advanced. One of the most important technologies is carrier.

Due to the current shortage of wireless spectrum resources, IMT-Advanced requires higher peak rate indicators (100 Mbps for high mobility and 1 Gbps for low mobility). The maximum 20 MHz bandwidth of the current LTE standard cannot meet IMT-Advanced. Required, so need to expand to higher bandwidth, such as 40MHz, 60MHz, or even higher. One of the methods to increase the bandwidth and peak rate is to expand the frequency domain. For example, the bandwidth of several 20MHz-based LTE bands is expanded by "carrier aggregation", which is the essence of carrier aggregation technology. Therefore, the LTE-Advanced system also belongs to a multi-carrier system. In the LTE-Advanced system, the carrier that participates in the aggregation is called a component carrier, and the user equipment (User Equipment, UE for short) can transmit and receive with the eNB on multiple component carriers at the same time. The component carrier can use the frequency band already defined by LTE, or it can also use the frequency band specially added for LTE-Advanced. Based on the current situation of tight spectrum resources, it is impossible to always allocate a continuous component carrier in the frequency domain to the operator, so the component carrier may be continuous or discontinuous in the frequency band. The concept of a primary cell and a secondary cell is introduced in the carrier aggregation. The primary cell refers to a cell in which the UE initiates an RRC connection establishment or an RRC connection reestablishment or is designated as a primary cell in the handover process; the secondary cell refers to a frequency point different from the primary cell, and Configured after the UE enters the RRC connected state, it is used to provide additional radio resources. In a carrier aggregation system, a serving cell includes a primary serving cell and a secondary serving cell. After the carrier aggregation technology is introduced, the UE can transmit and receive on multiple serving cells simultaneously in the RRC connection state (RRC_CO NECTED), but for the idle state (RRC_IDLE) UE, like the LTE-like, can only reside on one cell. After the UE successfully accesses the cell, that is, after the UE establishes an RRC connection on the cell, the base station may allocate a new cell to the UE through dedicated RRC signaling according to the service requirement, and after allocating the new cell, the base station and the UE The data is not immediately transmitted and received on the newly added cell, that is, the base station does not send service data to the UE on the newly added cell, and the UE saves the configuration information on the cell, and does not send the base station to the base station. Send service data and wait for further action by the base station. The subsequent base station can activate the cell according to the service requirement, and after the cell is activated, the base station and the UE can perform data transmission and reception on the cell. In the LTE system, in order to implement and maintain uplink synchronization between the user equipment and the base station, the base station sends a timing advance (Timing Advance, abbreviated as TA) to each user equipment according to the transmission delay between the base station and each user equipment. The device advances or delays the timing of the respective uplink transmission according to the timing advance sent by the base station, thereby compensating for the transmission delay of the user terminal to the base station, so that the uplink signals of different user equipments reach the base station within the receiving window of the base station. If the transmission delay between each cell in a cell configured for a certain UE is large and the same TA cannot be used, the concept of multiple TAs needs to be introduced in the carrier aggregation system. Depending on the use of the TA, UEs using the same TA can be placed in the same group, thus introducing the concept of grouping. In the previous carrier aggregation system, all carriers use the same TA, the primary cell serves as the cell that receives the TA control element, and the component carrier in which it is located also serves as the reference carrier for the uplink signal transmission of the UE, hereinafter referred to as the time reference carrier. The corresponding cell is called a time reference cell. However, when the concept of packet and multi-TA is introduced, since there are different packets and different TAs, if the primary cell is still only used as the cell and/or time reference cell receiving the TA control element, the packet and the multi-TA cannot be satisfied. It is required that the cell with a large difference in transmission delays cannot use the appropriate TA to adjust the uplink transmission timing, which may result in the base station side not receiving the uplink data of the partial cell, and causing the loss of the uplink data. SUMMARY OF THE INVENTION The present invention provides a cell selection method and apparatus in a multi-carrier communication system to at least solve the above problems. An aspect of the present invention provides a cell selection method in a multi-carrier communication system, including: for a packet including only a secondary cell, a UE and/or a base station respectively select a cell for receiving a TA control element for each of the packets And/or a cell used as a time reference. Preferably, the method for selecting a cell for receiving the TA control element and/or the cell for using the time reference includes at least one of the following: In a first mode, the base station configures the user equipment to receive a cell of the TA control element and/or a cell used as a time reference; mode 2, selecting a secondary cell in the packet that performs a RACH procedure as a cell for receiving a TA control element and/or a cell serving as a time reference; In the third mode, the secondary cell with the smallest or largest cell identifier in the secondary cell of the packet is selected as the secondary cell with the time reference, or the secondary cell with the smallest or largest cell identifier in the activated secondary cell in the packet is selected as the secondary cell. a secondary cell receiving a TA control element and/or a secondary cell serving as a time reference; mode 4, selecting a secondary cell activated by any one of the packets as a secondary cell for receiving a TA control element and/or serving as a time Reference secondary cell; mode 5, selecting the primary cell as a cell for receiving a TA control element in the secondary cell packet and/or serving as a time reference. Preferably, when the selected cell serving as the time reference is the secondary cell, in the case that the selected secondary cell serving as the time reference is activated and not activated, both are used as the secondary cells used as time references in the packet. The selected cell for receiving the TA Control Element acts as a cell for receiving the TA Control Element only if it has been activated. Preferably, after selecting a cell for receiving the TA control element and/or serving as a time reference for the packet, the method further comprising: selecting, at the selected secondary cell for receiving a TA control element and/or serving as a time reference In case of inactivation or deactivation, one secondary cell is reselected in the activated secondary cell in the packet as a secondary cell for receiving the TA control element and/or used as a time reference, or in the grouping Among the activated secondary cells, one secondary cell is reselected as the secondary cell for receiving the TA control element, and the secondary cell selected originally is reserved as the secondary cell used as the time reference. Preferably, after selecting the secondary cell for receiving the TA control element and/or serving as the time reference by using the mode 1, the method further includes: selecting, at the selected secondary cell for receiving the TA control element and serving as a time reference In the case of being inactive or deactivated, the base station reconfigures the secondary cell for receiving the TA control element to the user equipment in the manner of the activated secondary cell in the packet and/or a secondary cell that is referenced by the time, or the user equipment reselects the secondary cell for receiving the TA control element and/or used as the secondary cell in the second, fourth or fourth mode in the activated secondary cell in the packet. Secondary cell for time reference. Preferably, after selecting the secondary cell for receiving the TA control element and/or serving as a time reference by using the mode 2, the method further includes: selecting, at the selected secondary cell for receiving the TA control element and serving as a time reference If the user equipment is not activated or deactivated, the user equipment reselects the secondary cell for receiving the TA control element and/or by using the mode 2, mode 3 or mode 4 in the activated secondary cell in the packet. Used as a secondary cell for time reference. Preferably, after selecting the secondary cell for receiving the TA control element and/or serving as a time reference by using the mode 3, the method further includes: selecting, at the selected secondary cell for receiving the TA control element and serving as a time reference Unexcited In the case of live or deactivated, the user equipment reselects the secondary cell for receiving the TA control element and/or serves as a time reference in the secondary cell that has been activated in the packet by the mode three or the fourth mode. Secondary cell. Preferably, in a case that the first selected secondary cell changes from an unactivated state to an activated state, the user equipment resumes using the first selected secondary cell as the received control element in the packet and/or Or a cell used as a time reference. Another aspect of the present invention provides a cell selection apparatus in a carrier communication system, comprising: a selection module configured to select a cell for receiving a TA control element for each of the packets for a packet including only a secondary cell And/or a cell used as a time reference. Preferably, the cell selection device in the above carrier communication system is located in the base station and/or the UE. With the present invention, for a packet including only a secondary cell, the UE and/or the base station respectively select a cell for receiving the TA control element and/or a cell used as a time reference for each such packet, and the related art is introduced. After multiple TA packets, how does the secondary cell in the packet containing only the secondary cell select the time reference cell and/or how to select the cell receiving the timing advance TA control element, which is adapted to the multi-carrier communication system The requirements of the TA and the multi-packet can provide more accurate TA control for each packet, so that the uplink data of each UE falls into the receiving time window of the base station when it arrives at the base station, thereby reducing the probability of loss of uplink data, thereby improving The service performance of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set to illustrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, In the drawings: FIG. 1 is a schematic diagram of a cell selection method in a multi-carrier communication system according to an embodiment of the present invention; FIG. 2 is a schematic diagram of coverage of carrier aggregation according to an embodiment of the present invention; Detailed flowchart of a cell selection method in a multi-carrier communication system; FIG. 4 is a detailed flowchart of a cell selection method in a multi-carrier communication system according to Embodiment 2; FIG. 5 is a multi-carrier communication system according to Embodiment 3. Detailed flowchart of a cell selection method; FIG. 6 is a detailed flowchart of a cell selection method in a multi-carrier communication system according to Embodiment 4; 7 is a detailed flowchart of a cell selection method in a multi-carrier communication system according to Embodiment 5; and FIG. 8 is a detailed flowchart of a cell selection method in the multi-carrier communication system according to Embodiment 6. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. In the previous carrier aggregation system, all carriers use the same TA, and the primary cell serves as the cell that receives the TA control element, and also serves as the reference carrier for the uplink signal transmission of the UE. It is not sufficient to use only the primary cell as the receiving TA control element and/or the time reference carrier after introducing the concept of the packet and the multi-TA, and it is necessary to select one cell in each packet as the receiving TA control element and/or the time reference carrier. In the packet including the primary cell, the primary cell may continue to be used as the receiving TA control element and/or the time reference carrier; in the group containing only multiple secondary cells, one may be selected (the cell and time reference in receiving the TA control element) In the case where the cells are all selected and the two are different, there may be two) secondary cells as the receiving TA control elements and/or time reference carriers of the group. 1 is a schematic diagram of a cell selection method in a multi-carrier communication system according to an embodiment of the present invention. As shown in FIG. 1, in a method, for a packet including only a secondary cell, a UE and/or a base station is for each such packet. Cells for receiving TA control elements and/or cells for use as time references are selected, respectively. By this method, the multi-TA carrier aggregation system can select a cell for receiving a TA control element and/or a cell as a time reference for each packet including only a plurality of secondary cells by the UE and/or the base station, respectively. In a practical application, for a packet including only a secondary cell, a secondary cell for receiving a TA control element and/or a secondary cell serving as a time reference may be selected for the packet in the secondary cell included in the packet, or The primary cell is used as the secondary cell packet for receiving a cell of the TA control element and/or a cell for use as a time reference. The method solves the problem of how the secondary cell in the packet including only the secondary cell selects the time reference cell and/or how to select the cell receiving the time advance TA control element after the multiple TA packets are introduced, and the solution is adapted to the problem. The requirement of multiple TAs and multiple packets in the carrier communication system can provide more accurate TA control for each packet, so that the uplink data of each UE falls into the receiving time window of the base station when the base station arrives, and the uplink data is reduced. The probability of loss, thus improving the service performance of the entire system. It should be noted that, in the foregoing description and FIG. 1, for a packet including a primary cell, a primary carrier is selected as a cell for receiving a TA control element and/or used as a time reference, but is proposed in the embodiment of the present invention. For a cell selection method that includes only a packet of a secondary cell, there is no particular restriction on how a packet including a primary cell is selected for receiving a TA control element and/or a cell used as a time reference, and for a packet including a primary cell, Whether the primary cell is selected according to the prior art or other cells are selected by other methods does not affect the implementation of the method. Does not affect the problem of how to solve the problem of how the secondary cell in the packet including only the secondary cell selects the time reference cell and/or how to select the cell receiving the timing advance TA control element after the multiple TA packets are introduced. In a practical application, a plurality of methods may be used to select a cell for receiving a TA control element and/or a cell used as a time reference, for example: In a first mode, the base station configures a cell for receiving a TA control element to the user equipment and/or Or a cell used as a time reference. Preferably, the base station may perform such a configuration operation when configuring the secondary cell and the grouping information of each cell for the user equipment. In this manner, when the base station configures the secondary cell and the packet information of the cell for the UE, the receiving the TA control element and/or the cell identifier as the time reference cell may be configured by using an RRC related message (for the sake of simplicity, the RRC connection reconfiguration message may be adopted) . The UE stores the configuration information after receiving, and the cell configured as the time reference can be used as the time reference cell in the secondary cell activation/deactivation state, and the secondary cell configured to receive the TA control element is used as the receiving TA control in the active state. The cell of the element, or the cell receiving the TA control element, may also be considered as a time reference cell. Manner 2: The secondary cell in the packet performing the random access channel RACH procedure is selected as the cell for receiving the TA control element and/or the cell used as the time reference. In this manner, the base station does not perform explicit signaling configuration on the cell that receives the TA control element and/or the time reference in the packet including only the secondary cell, but selects the cell in the packet that performs the RACH procedure as the receiving TA control. Element and / or time reference cell. In a group that only includes a secondary cell, one cell needs to perform an uplink synchronization process after activation, so that all cells in the packet enter an uplink synchronization state, and the cell can also serve as a receiving TA control element and/or a time reference cell. In the third mode, the secondary cell with the smallest or largest cell identifier in all the secondary cells of the packet is selected as the secondary cell used as the time reference, or the secondary cell with the smallest or largest cell identifier in the activated secondary cell in the selected packet is used for receiving. A secondary cell of the TA Control Element and/or a secondary cell used as a time reference. In this mode, the base station does not use the signaling to perform the explicit indication, and the base station and the UE only include the secondary cell with the smallest or largest cell identifier in the packet of the secondary cell as the secondary reference of the time reference by default; or the base station and the UE only include the secondary cell by default. The secondary cell with the smallest or largest cell identity in the secondary cell is activated in the packet as the secondary cell receiving the TA control element and/or time reference. Manner 4, the secondary cell that is activated in the group is selected as the secondary cell for receiving the TA control element and/or the secondary cell used as the time reference. In this manner, if multiple secondary cells are activated, After the UE selects, the selection result is notified to the base station, thereby ensuring the consistency of the cells selected by the two, and facilitating the subsequent synchronization process. Preferably, when the selected cell used as the time reference is the secondary cell, if the selected secondary cell is activated and not activated, it can be used as a secondary cell used as a time reference in the packet; The cell of the control element acts as a cell for receiving the TA Control Element only if it has been activated. If the selected cell is not currently active, in order to receive the TA control element, it may be necessary to reselect an activated secondary cell, thus selecting a secondary control element for the packet and/or as a time reference for the packet. After the cell, in the case where the selected secondary cell for receiving the TA control element and/or used as the time reference is not activated or deactivated, one secondary cell is reselected in the secondary cell activated in the packet as for receiving a TA control element and/or a secondary cell used as a time reference, or reselecting one secondary cell as a secondary cell for receiving a TA control element in a secondary cell that has been activated in the packet, and retaining the previously selected secondary cell as a secondary cell A secondary cell for time reference. In practical applications, the above manners one to four can be used in combination in the process of first selection and reselection, for example: (1) In the first mode, a secondary cell for receiving a TA control element and/or serving as a time reference is selected. Then, in the case that the selected secondary cell for receiving the TA control element and used as the time reference is not activated or deactivated, the base station is configured to receive the user equipment again for receiving in the secondary cell that has been activated in the packet. The secondary cell of the TA control element and/or the secondary cell used as the time reference, or the user equipment reselects the secondary cell for receiving the TA control element by means 2, 3 or 4 in the secondary cell activated in the packet And/or as a secondary cell for time reference.

(2) After selecting the secondary cell for receiving the TA control element and/or serving as the time reference in mode 2, the selected secondary cell for receiving the TA control element and serving as the time reference is not activated or deactivated. In this case, the user equipment reselects the secondary cell for receiving the TA control element and/or the secondary cell used as the time reference by means 2, 3 or 4 in the secondary cell activated in the packet. (3) After the mode 3 is selected for receiving the TA control element and/or the secondary cell used as the time reference, the selected secondary cell for receiving the TA control element and used as the time reference is not activated or deactivated In this case, the user equipment reselects the secondary cell for receiving the TA control element and/or the secondary cell used as the time reference by means 3 or 4 in the secondary cell activated in the packet. In addition, in the case that the first selected secondary cell changes from the unactivated state to the activated state, the user equipment can also restore the first selected secondary cell as a packet for receiving the TA control element and/or used as a time reference. Community. In the above method, the multi-TA carrier aggregation system selects a receiving TA control element and/or a cell as a time reference in a packet including only the secondary cell. The method has a modification to the overall description protocol of the multi-carrier system, that is, it is clear that in the multi-TA multi-carrier system, it is necessary to select one receiving TA control element and/or as a time reference in the packet including only the secondary cell; The configuration process of the UE may be modified for the RRC protocol of the UE, that is, the configuration parameter needs to be added to indicate the receiving TA control element in the group and/or the cell as a time reference; In addition, the selection principle of receiving the TA control element and/or the cell as a time reference may also be explicitly selected by modifying the MAC protocol. Manner 5: The primary cell is selected as a cell containing only the secondary cell for receiving the TA control element and/or serving as a time reference. The UE may receive a TA Control Element for Secondary Cell Packet Time Adjustment on the primary cell, applying the control element to the secondary cell packet. It should be noted that, for a packet including multiple packets including only the secondary cell, for different packets, a cell for receiving the TA control element may be selected for each packet and/or used for each packet in a unified manner. a time referenced cell; each cell may also select a respective mode to select a cell for receiving the TA control element and/or a cell used as a time reference, and the selected modes may be different or partially identical, of course. , or all the same. The embodiment of the present invention further provides a cell selection apparatus in a carrier communication system, including: a selecting module, configured to respectively select a cell for receiving a timing advance TA control element for each packet including only the secondary cell and/or A cell used as a time reference. The device can be located in a base station and/or user equipment. The apparatus can perform the method described in the foregoing embodiments, adapts to the demand for multiple TAs and multiple packets in a multi-carrier communication system, and can provide more accurate TA control for each packet, so that uplink data of each UE arrives at the base station. The time falls into the receiving time window of the base station, which reduces the probability of loss of uplink data, thereby improving the service performance of the entire system. It should be noted that the selection module of the cell selection apparatus in the above carrier communication system may perform the selection of the cell for receiving the TA control element and/or the cell used as the time reference by referring to the manner described in the foregoing embodiments, where Let me repeat. 2 is a schematic diagram of coverage of carrier aggregation in accordance with an embodiment of the present invention. As shown in Figure 2, the serving cell 1 (downlink frequency fl, uplink frequency point fl '), referred to as CC1 (DL fl , UL fl '); serving cell 2 (downstream frequency point £2, uplink frequency point £2' ), abbreviated as CC2 (DL £2, UL £2'); serving cell 3 (downstream frequency point β, uplink frequency point β') _; serving cell 4 (downlink frequency point f4, uplink frequency point f4') can carry out carrier polymerization. The user equipment UE camps on CC1 and initiates an RRC connection procedure on CC1, CC1 is considered to be the primary serving cell of the UE, and CC1 is in group 1. The serving cells CC2, CC3 and CC4 are secondary cells, in group 2. The cell IDs of CC1 to CC4 are 1~4 respectively. The following takes the scenario shown in FIG. 2 as an example. The cell selection in the multi-carrier communication system provided by the embodiment of the present invention is described in detail by using a frequency division duplex mode (FDD) as an example. Solution, Embodiments 1-5 combine the technical solutions of the above plurality of preferred embodiments. Example 1 3 is a detailed flowchart of a cell selection method in a multi-carrier communication system according to Embodiment 1, as shown in FIG. 3, including the following steps: Step 301: A UE initiates an RRC connection on CC1, and the base station is in an RRC connection reconfiguration message. The information of CC2, CC3 and CC4 and the grouping information are configured to the UE. CC1 is the primary serving cell, which is group 1 and CC2-CC4 is the secondary serving cell, which is group 2; the base station simultaneously configures CC2 as the secondary control unit in group 2 and/or as the time reference in the RRC connection reconfiguration message. a cell: Step 302: The base station activates the CC3 when the UE is in the RRC connection state, and after the CC3 completes the uplink synchronization, the CC3 serves as the cell that maintains the TA and/or the time reference in the group 2; at this time, the CC2 can also be used as the time reference cell; Step 303: The base station activates CC2 and CC4 when the UE is in the RRC connected state. According to the configuration information of the base station, CC2 is used as the cell that receives the TA control element and/or the time reference in the group 2, and the CC3 is no longer used as the receiving TA in the group 2. Control element and/or time referenced cell; Step 304: When CC2's deactivation timer expires, CC2 is deactivated. At this time, the base station immediately sends a deactivated MAC control element to activate CC3 and CC4. Step 305: The base station sends RRC signaling to notify the UE to change CC3 as a cell that receives the TA control element and/or time reference; or the UE deactivates CC3 and CC4 by itself. The base station sends RRC signaling to notify the UE to change CC3 to receive the TA control element and the time referenced cell; or after the CC2 is deactivated, the base station does not deactivate CC3 and CC4, but directly sends RRC signaling to notify the UE to change CC3 as the receiving TA control element. And/or the time reference cell; if the step is performed, the process directly proceeds to step 307; Step 306: The base station sends the secondary cell activation MAC control element to activate CC3 and CC4, and the base station does not instruct the group 2 to perform the initial uplink synchronization process (or the indication group 2) If the initial uplink synchronization is not performed, it is considered that the group 2 is already in the uplink synchronization state; Step 307: the UE activates the CC3 and the CC4 after receiving the control element, and receives the TA control element of the group 2 and/or uses the CC3 as the time reference cell on the CC3. . Step 308: The UE receives the RRC connection reconfiguration message and applies the configuration parameters therein, uses CC3 as the time reference cell, and receives the TA control element on CC3. Example 2 4 is a detailed flowchart of a cell selection method in a multi-carrier communication system according to Embodiment 2. As shown in FIG. 4, the method includes the following steps: Step 401: A UE initiates an RRC connection on CC1, and the base station is in an RRC connection reconfiguration message. The information of CC2, CC3 and CC4 and the grouping information are configured to the UE. CC1 is the primary serving cell, which is group 1 and CC2-CC4 is the secondary serving cell, which is group 2; the base station simultaneously configures CC2 as the secondary control unit in group 2 and/or as the time reference in the RRC connection reconfiguration message. a cell; the base station activates the CC3 when the UE is in the RRC connection state, and after the CC3 completes the uplink synchronization, the CC3 serves as the cell that receives the TA control element and/or the time reference in the group 2; at this time, the CC2 can also serve as the time reference cell; Step 403: The base station reactivates CC2 and CC4 when the UE is in the RRC connected state, and the currently activated cells in the group 2 are CC2~CC4. According to the RRC configuration of the base station, CC2 needs to be a cell that receives the TA control element and/or time reference at this time. CC3 will no longer be the cell that receives the TA control element and/or the time reference. Step 404: After the period of time, if CC2 is deactivated, the secondary cells activated in group 2 are CC3 and CC4, and the active cell is selected. The secondary cell with the smallest cell identifier is used as the cell that receives the TA control element and/or the time reference, and CC3 is selected; at this time, CC2 can also serve as the time reference cell; Step 405: After the segment time, if the base station sends the secondary cell activation control element to be activated again CC2, then CC2 is again changed to receive the TA control element and/or time synchronized cell, and CC3 is no longer used as the reference cell for receiving the TA control element and/or time synchronization. Embodiment 3 FIG. 5 is a detailed flowchart of a cell selection method in a multi-carrier communication system according to Embodiment 3. As shown in FIG. 5, the method includes the following steps: Step 501: A UE initiates an RRC connection on CC1, and the base station is in an RRC connection. The information of the CC2, CC3, and CC4 and the packet information are configured to the UE in the reconfiguration message. CC1 is the primary serving cell, which is group 1 and CC2-CC4 is the secondary serving cell, which is group 2; the secondary cell with the smallest default cell identifier of the base station and the UE can be used as the time reference cell in group 2; the base station and the UE activate the cell in the cell by default. The smallest secondary cell is marked as the cell that receives the TA control element and/or the time reference; Step 502: The base station activates CC3 when the UE is in the RRC connected state, and after CC3 completes the uplink synchronization, the CC3 serves as the cell that receives the TA control element and the time reference. Or CC3 only receives the TA control element, CC2 as the time reference cell; Step 503: The base station reactivates CC2 and CC4 when the UE is in the RRC connected state, and the currently activated cells in the group 2 are CC2~CC4. At this time, the secondary cell with the smallest cell identifier in group 2 is CC2, and the TA control element is received by CC2 and/or is used as the time reference cell. The TA control element is no longer received on CC3, and CC3 is not used as the time reference cell. Step 504: After the time, if CC2 is deactivated, the secondary cells activated in group 2 are CC3 and CC4. At this time, the secondary cell with the smallest cell indication in the active cell is selected as the cell receiving the TA control element and/or time reference, and CC3 is selected. At this time, CC2 can also serve as a time reference cell. Embodiment 4 FIG. 6 is a detailed flowchart of a cell selection method in a multi-carrier communication system according to Embodiment 4. As shown in FIG. 6, the method includes the following steps: Step 601: The UE is in An RRC connection is initiated on CC1, and the base station configures information of CC2, CC3, and CC4 and packet information to the UE in an RRC connection reconfiguration message. CC1 is the primary serving cell, which is group 1 and CC2-CC4 is the secondary serving cell, which is group 2; the base station configures random access resources in CC2, which is used to initiate the RACH process when uplink synchronization occurs in group 2; A cell configured with a random access resource is configured as a receiving TA control element and/or a time reference cell. Step 602: Since group 2 and group 1 use different TAs for timing adjustment, the secondary cell in group 2 needs to have at least one initial activation. A cell performs an initial uplink synchronization process. CC2 is configured with random access resources, then the base station needs to activate CC2 so that the UE uses the random access resources on CC2 for uplink synchronization, and the base station sends the secondary cell to activate the MAC control element to activate CC2, CC3, CC4; Step 603: The UE is applying the auxiliary CC2 is activated after the cell control element, and the initial uplink synchronization process is completed on CC2. The base station and the UE configure CC2 of the RACH resource as the cell that receives the TA control element and/or the time reference; Step 604: When the deactivation timer of CC2 times out, CC2 is deactivated, and CC3 and CC4 are in an active state. Selecting the secondary cell with the smallest cell identifier in the active cell as the cell receiving the TA control element and the time reference, and selecting CC3; or CC3 is only the cell receiving the TA control element, and CC2 is still used as the time reference cell; Step 605: After the time, The base station sends an activated secondary cell control element to reactivate CC2. At this time, CC2 becomes a receiving TA control element and/or a time reference cell, and CC3 no longer receives the TA control element. If CC3 is previously used as a time reference cell, then subsequent CC3 does not act as time. Reference cell. Embodiment 5 FIG. 7 is a detailed flowchart of a cell selection method in a multi-carrier communication system according to Embodiment 5. As shown in FIG. 7, the method includes the following steps: Step 701: A UE initiates an RRC connection on CC1, and the base station is in an RRC connection. The information of the CC2, CC3, and CC4 and the packet information are configured to the UE in the reconfiguration message. CC1 is the primary serving cell, which is group 1 and CC2-CC4 is the secondary serving cell, which is group 2; the base station configures random access resources in CC2, which is used to initiate the RACH process when uplink synchronization occurs in group 2; A cell configured with a random access resource is used as a receiving TA control element or/and a time reference cell. Step 702: Same as step 602 of Embodiment 4. Step 703: Same as step 603 of Embodiment 4. Step 704: When the deactivation timer of CC2 times out, CC2 is deactivated; at this time, the base station sends a secondary cell deactivation control element to deactivate CC3 and CC4. Or the base station and the UE default to CC3 and CC4 have been deactivated at this time. Step 705: The base station sends an RRC connection reconfiguration message, where the message carries the random access resource of the CC3, and is used in the uplink synchronization initiation RACH process in the group 2. Step 706: The base station sends a secondary cell activation control element to activate CC3 and CC4. Step 707: The base station instructs the UE to initiate uplink synchronization of the group 2 on the CC3. Step 708: After the uplink synchronization of the CC3 is completed, the group 2 enters the synchronization state, and the CC3 can serve as the receiving TA and the time reference cell; or the CC3 is only the cell that receives the TA, and the CC2 can still serve as the time reference cell. Embodiment 6 FIG. 8 is a detailed flowchart of a cell selection method in a multi-carrier communication system according to Embodiment 6. As shown in FIG. 8, the method includes the following steps: Step 801: A UE initiates an RRC connection on CC1, and the base station is in an RRC connection. The information of the CC2, CC3, and CC4 and the packet information are configured to the UE in the reconfiguration message. CC1 is the primary serving cell, which is group 1 and CC2-CC4 is the secondary serving cell, which is group 2; the base station configures random access resources in CC2 for uplink synchronization in group 2. Initiating a RACH procedure; the base station and the UE consider the cell configured with the random access resource as the receiving TA control element and/or the time reference cell; Step 802: Since Group 2 and Group 1 use different TAs for timing adjustment, then Group 2 When the secondary cell in the first activation is activated, at least one cell needs to perform an initial uplink synchronization process. CC2 is configured with random access resources, then the base station needs to activate CC2 so that the UE uses the random access resources on CC2 for uplink synchronization, and the base station sends the secondary cell activation MAC control element to activate CC2, CC3, CC4; Step 803: The UE is applying the auxiliary CC2 is activated after the cell control element, and the initial uplink synchronization process is completed on CC2. CC3 and CC4 also enter the uplink synchronization state, the UE can perform uplink transmission on CC2, CC3, and CC4, and CC1 can serve as the time reference cell of these cells; Step 804: The base station sends the UE to the UE on CC1. The time adjustment control element of 2 indicates that the control element is sent to group 2 by the cell identifier in the control element. Step 805: The UE receives the ΤΑ control element on the CC1, and reads the identifier carried in the control element to find that the control element is used for the time adjustment of the group 2. Then, the group 2 applies the time adjustment ΤΑ control element. CC1 acts as a cell that receives the ΤΑ control element. From the above description, it can be seen that the present invention solves the related art, how to select a time reference cell in a secondary cell in a packet including only a secondary cell after the introduction of multiple ΤΑ packets, and how to select a reception time advance amount ΤΑ control The problem of the cell of the element, the solution adapts to the demand for multiple and multiple packets in the multi-carrier communication system, and can provide more accurate control for each packet, so that the uplink data of each UE falls into the base station. Within the receiving time window of the base station, the probability of loss of uplink data is reduced, thereby improving the service performance of the entire system. Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general-purpose computing device, which can be concentrated on a single computing device or distributed over a network composed of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device so that they may be stored in the storage device by the computing device, or they may be separately fabricated into individual integrated circuit modules, or Multiple modules or steps are made into a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software. The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

A cell selection method in a multi-carrier communication system, comprising:

For a packet containing only the secondary cell, the user equipment UE and/or the base station respectively select a cell for receiving the timing advance TA control element and/or a cell serving as a time reference for each of the packets.

2. The method according to claim 1, wherein the manner of selecting a cell for receiving a TA control element and/or a cell serving as a time reference comprises at least one of the following:

In a first mode, the base station configures, to the user equipment, a cell for receiving a TA control element and/or a cell used as a time reference. In a second manner, selecting a secondary cell in the packet to perform a random access channel (RACH) process is used for receiving. a cell of the TA control element and/or a cell used as a time reference;

In the third mode, the secondary cell with the smallest or largest cell identifier in the secondary cell of the packet is selected as the secondary cell with the time reference, or the secondary cell with the smallest or largest cell identifier in the activated secondary cell in the packet is selected as the secondary cell. a secondary cell receiving a TA control element and/or a secondary cell serving as a time reference;

Manner 4, selecting a secondary cell activated by any one of the packets as a secondary cell for receiving a TA control element and/or a secondary cell serving as a time reference;

In a fifth mode, the primary cell is selected as a cell for receiving a TA control element in the secondary cell packet and/or as a time reference.

The method according to claim 1 or 2, wherein, when the selected cell serving as a time reference is a secondary cell, in a case where the selected secondary cell serving as a time reference is activated and inactive, As a secondary cell used as a time reference in the packet; the selected cell for receiving the TA control element acts as a cell for receiving the TA control element only if it has been activated.

4. The method according to claim 2, wherein after selecting a cell for receiving the TA control element and/or serving as a time reference for the packet, the method further includes:

In case the selected secondary cell for receiving the TA control element and/or serving as a time reference is not activated or deactivated, one secondary cell is reselected in the activated secondary cell in the packet as Receiving a TA control element and/or a secondary cell used as a time reference, or A secondary cell is reselected in the activated secondary cell as a secondary cell for receiving the TA control element, and the secondary cell selected originally is reserved as the secondary cell used as a time reference. The method according to claim 4, further comprising: after selecting the secondary cell for receiving the TA control element and/or serving as a time reference by using the mode one, further comprising:

In the case that the selected secondary cell for receiving the TA control element and used as a time reference is not activated or deactivated, the base station re-routes through the mode in the activated secondary cell in the packet. The user equipment is configured to receive a secondary cell of the TA control element and/or a secondary cell used as a time reference, or the user equipment passes the mode 2, mode 3 in the activated secondary cell in the packet. Or mode four reselects the secondary cell for receiving the TA control element and/or the secondary cell used as the time reference. The method according to claim 4, wherein after selecting the secondary control element for receiving the TA control element and/or serving as a time reference by using the mode 2, the method further includes:

In the case that the selected secondary cell for receiving the TA control element and serving as a time reference is not activated or deactivated, the user equipment passes the mode in the secondary cell that has been activated in the packet. Mode 3 or Mode 4 reselects the secondary cell used to receive the TA Control Element and/or the secondary cell used as the time reference. The method according to claim 4, wherein, after the mode 3 is selected to receive the TA control element and/or the secondary cell used as a time reference, the method further includes:

In the case that the selected secondary cell for receiving the TA control element and used as a time reference is not activated or deactivated, the user equipment passes the mode three in the activated secondary cell in the packet. Mode 4 reselects the secondary cell used to receive the TA Control Element and/or the secondary cell used as the time reference. The method according to any one of claims 4-7, wherein, in a case where the first selected secondary cell changes from an unactivated state to an activated state, the user equipment resumes the first selected secondary The cell acts as a cell in the packet for receiving TA control elements and/or for use as a time reference. A cell selection device in a carrier communication system includes:

The selection module is arranged to select a cell for receiving the time advance TA control element and/or a cell for use as a time reference, respectively, for each packet containing only the secondary cell. The apparatus according to claim 9, wherein the apparatus is located in a base station and/or a user equipment UE.