Method for performing random access procedure by user equipment

Abstract

A method for performing, by a UE (User Equipment), a RA (Random Access) procedure in a cell of a gNB (Next Generation Node B) of a mobile network is provided. The UE activates the primary PCell based on the first data. The UE receives second data for one or more secondary PCells from the gNB, the second data being used to (i) configure the one or more secondary PCells, and to (ii) perform an RA procedure in the one or more secondary PCells. The UE further receives third data from the gNB, the third data indicating which secondary PCell of the one or more secondary PCells is to be activated. After the UE determines that the primary PCell is turned off, it activates the indicated secondary PCell based on the second data and the third data. The UE performs an RA procedure in the activated secondary PCell based on the second data.

Description

Background Art

[0001] The present invention relates to a method for performing or implementing a RA (Random Access) procedure by a UE (User Equipment) in a cell of a gNB (Next Generation Node B) of a mobile network.

[0002] In a mobile network, a UE (e.g., a mobile phone) may be configured with one primary cell or PCell and up to 15 secondary cells, called secondary cells or SCells. These cells are provided by a single base station, which may be referred to as a next generation Node B in the 3GPP standard.

[0003] PCell provides basic control of UE, such as RRC connection management, radio bearer management, mobility management, etc. SCell is used as an additional radio resource of UE, and its addition or removal depends on the traffic volume.

[0004] The purpose of the RA (Random Access) procedure of the UE is to request uplink radio resources and align uplink transmission timing. Since the same transmission buffer and the same transmission timing of the gNB are used for all cells, there is no need to perform the RA procedure in the SCell, and in fact, in the current version of the relevant 3GPP standard, such a RA procedure is not allowed in the SCell.

[0005] In order to improve network energy saving in terms of base station transmission and reception energy consumption, a cell can be temporarily shut down when the expected traffic volume is below a fixed threshold. The cell shutdown period can be less than one second or on the order of milliseconds.

[0006] Therefore, the network may shut down the PCell of the UE. The UE may not be able to initiate a RA procedure in its SCell and will therefore delay its RACH (Random Access Channel) procedure until the PCell is turned on again. This will increase latency and / or delay in data transmission. This increased latency and / or delay is not beneficial for high priority data transmission.

[0007] The purpose of the present invention is to reduce the delay and / or latency when the PCell of a UE is turned off. Summary of the invention

[0008] The object of the present invention is achieved by providing a method according to claims 1 and 4 , a UE according to claim 12 , and a network node according to claim 13 .

[0009] According to a first aspect, there is provided a method for performing a RA (Random Access) procedure by a UE (User Equipment) in a cell of a gNB (Next Generation Node B) of a mobile network, the method preferably being performed in the UE, wherein the method comprises the following steps:

[0010] - receiving first data about a primary PCell (primary cell) from a gNB, the first data being used to configure the primary PCell;

[0011] - based on the first data, activating the primary PCell;

[0012] - using the activated primary PCell, receiving second data about one or more secondary PCells from the gNB, the second data being used for (i) configuring the one or more secondary PCells and for (ii) performing a RA procedure in the one or more secondary PCells;

[0013] - receiving third data from the gNB, the third data indicating which secondary PCell of the one or more secondary PCells is to be activated;

[0014] -determining that the primary PCell is turned off;

[0015] - based on the second data and the third data, activating the indicated secondary PCell; and

[0016] - Based on the second data, performing a RA procedure in the activated secondary PCell, and optionally performing a RACH (Random Access Channel) procedure in the activated secondary PCell.

[0017] According to the present invention, information (i.e., the second data and the third data) can be provided to the UE for quickly switching to the new PCell (i.e., the secondary PCell) when the old PCell (i.e., the primary PCell) is turned off. In the new PCell, the UE can perform the RA procedure and optionally the RACH procedure. This will reduce any delay and / or latency in data transmission.

[0018] An alternative procedure for the UE to activate a new PCell is a so-called handover procedure when the UE switches from one gNB to another. Such a handover procedure requires a large amount of data or information to be exchanged between at least the UE and the new gNB (at least more than the data according to the present invention). This may increase delay and latency and increase overall power consumption.

[0019] The user equipment may be a vehicle, a mobile phone, or any other device arranged to be connected to a communication network, preferably a wireless network, arranged to be connected to a communication network. An example of such a communication network is a cellular mobile network, such as that defined by 3GPP, for example, by the currently frozen Release 16 of 3GPP.

[0020] In one or more embodiments, the first data and / or the second data may be received as RRC information or RRC message (RRC=Radio Resource Control).In one or more embodiments, the second data may be transmitted and received once, for example, together with the first data.

[0021] In other embodiments, the second data may be sent and received periodically. In still other embodiments, the transmission of the second data is triggered by a change in a set of one or more available secondary PCells as determined by the gNB or the network. The second data may include information about an index number identifying each of the one or more available secondary PCells.

[0022] In one or more embodiments, the third data may be received as MAC CE (Media Access Control Element) information. In another embodiment, the third data is included in a MAC header. In one or more embodiments, the third data may be sent and received periodically.

[0023] In some further embodiments, the transmission of the third data is triggered when the network (or gNB) determines that a new cell (i.e., a cell different from the cell identified in the previously transmitted third data) will become a secondary PCell after the primary PCell is turned off. In some further embodiments, the transmission of the third data is triggered when the network (or gNB) determines that the primary PCell is to be turned off.

[0024] In one or more embodiments, determining which one of the one or more secondary PCells is to be activated is based on a comparison of traffic volumes of the one or more secondary PCells and / or a comparison of signal strengths of the one or more secondary PCells.

[0025] It is expected that the third data is transmitted more frequently than the second data. Since the third data may only need to include an index number, its transmission and processing may require little processing time (and / or processing energy), which may further reduce delay and / or latency.

[0026] In one or more embodiments, the third data may be received and sent periodically. In fact, in order to save network energy, the cell may be shut down periodically. In this case, switching to the new PCell may also be completed periodically.

[0027] In one or more embodiments, the third data may include a scheme indicating when which secondary PCell of the plurality of secondary PCells is activated. In order to reduce network energy consumption, cells may be turned off according to an energy saving plan indicating when which cell will be turned off in an upcoming time period. When this plan is known, the third data may be sent / received only once to indicate when which secondary PCells will be activated during the upcoming time period.

[0028] The UE may determine that the primary PCell is switched off based on information received from the gNB or based on signal loss of the primary PCell.

[0029] In one or more embodiments, the method further comprises the following steps:

[0030] - using the activated primary PCell, receiving fourth data about one or more SCells allocated to the secondary PCell from the gNB, the fourth data being used to configure the one or more SCells;

[0031] - based on the fourth data, activating one or more SCells allocated to the primary PCell;

[0032] In one or more embodiments, the method further comprises the following steps:

[0033] - using the activated secondary PCell, receiving fifth data about one or more SCells allocated to the secondary PCell from the gNB, the fifth data being used to configure the one or more SCells;

[0034] - Based on the fifth data, activate one or more SCells allocated to the secondary PCell.

[0035] As described above, the UE may use the SCell near the PCell as an additional wireless resource.

[0036] In one or more embodiments, the method further comprises the following steps:

[0037] - receiving information about the shutdown period of the primary PCell;

[0038] -determining that the primary PCell is switched off based on the received information; and optionally,

[0039] - after determining that the shutdown period ends, reactivating the primary PCell and deactivating the secondary PCell, and optionally, reactivating the SCell allocated to the primary PCell and deactivating the SCell allocated to the secondary PCell.

[0040] The deactivation period of a PCell may be relatively short, for example, less than 1 second, or even a few milliseconds. In this case, it may be beneficial for the UE to immediately use another PCell (secondary PCell) when its current PCell (primary PCell) is deactivated.

[0041] In one or more embodiments, the UE may calculate the start and / or end of the off period based on information about the off period and time information from an internal clock.

[0042] In one or more embodiments, the information about the closing period includes information about a closing time at which the closing period starts. In one or more embodiments, the information about the closing period is included in the third data.

[0043] According to a second aspect, a method for causing a UE to perform a RA procedure in a cell of a gNB (next generation Node B) of a mobile network is provided, the method preferably being performed in the gNB, wherein the method comprises the following steps:

[0044] - sending first data about a primary PCell to the UE, where the first data is used to configure the primary PCell;

[0045] - sending second data about one or more secondary PCells to the UE, the second data being used for (i) configuring the one or more secondary PCells and for (ii) performing a RA procedure in the one or more secondary PCells;

[0046] -determining that the primary PCell is to be shut down;

[0047] -When the primary PCell is deactivated, determining which secondary PCell of the one or more secondary PCells is to be activated by the UE;

[0048] - sending third data indicating the determined secondary PCell to the UE;

[0049] - Shut down the master PCell.

[0050] In one or more embodiments, the method further comprises the following steps:

[0051] - determining that the primary PCell is to be switched off during a switch-off period, the switch-off period starting at a switch-off time;

[0052] -sending information about the shutdown period and / or the shutdown time to the UE; and optionally,

[0053] - After the shutdown period ends, turning on the primary PCell.

[0054] In one or more embodiments, the method further comprises the following steps:

[0055] - Establishing a power saving plan that indicates which PCell will be switched off and at what time during the upcoming time period;

[0056] - based on the energy saving plan, determining a scheme indicating when which of the plurality of secondary PCells will be activated in the upcoming time period;

[0057] Wherein, the third data includes the scheme.

[0058] In one or more embodiments, the method further comprises the following steps:

[0059] - using the activated primary PCell, sending to the UE fourth data about one or more SCells allocated to the primary PCell, the fourth data being used to configure the one or more SCells; and / or,

[0060] - Using the activated secondary PCell, sending fifth data about one or more SCells allocated to the secondary PCell to the UE, where the fifth data is used to configure the one or more SCells.

[0061] In one or more embodiments, the method further comprises the following steps:

[0062] - Selecting said one or more secondary PCells from said one or more SCells allocated to said primary PCell, preferably based on a predetermined traffic volume threshold.

[0063] In one or more embodiments, the determining which one of the one or more secondary PCells is to be activated is based on a comparison of traffic volumes of the one or more secondary PCells and / or a comparison of signal strengths of the one or more secondary PCells.

[0064] In one or more embodiments, the second data about one or more secondary PCells includes, for each of the PCells, information about an index number identifying the secondary PCell, information about a BWP (Bandwidth Path), and / or information about a RACH resource configuration.

[0065] In one or more embodiments,

[0066] - the first data, the fourth data and the fifth data are included in RRC (Radio Resource Control) information; and / or,

[0067] - the second data is included in RRC information or MAC CE (Medium Access Control Element) information; and / or,

[0068] -The third data is included in MAC CE information or RRC information.

[0069] In one or more embodiments, the first data and / or the second data and / or the fourth data are sent by the gNB to the UE together as a single RRC message.

[0070] According to a third aspect, there is provided a UE (User Equipment) arranged to perform a RA procedure in a cell of a gNB of a mobile network; comprising:

[0071] - one or more transceivers for communicating with the gNB using one or more PCells and / or SCells of the gNB;

[0072] - a processor for executing the steps of a computer program;

[0073] - A computer readable medium having stored thereon a computer program, the computer program comprising instructions which, when executed by the processing unit, cause the UE to perform the steps of the method as claimed in any one of claims 1 to 3 and any one of claims 9 to 12 as dependent thereon.

[0074] According to a fourth aspect, there is provided a mobile network node, preferably a gNB, the node being arranged to cause a UE to perform a RA procedure in a cell of the node, comprising:

[0075] - one or more transceivers for communicating with the UE using one or more PCells and / or SCells of the node;

[0076] - a processor for executing the steps of a computer program;

[0077] - A computer readable medium having stored thereon a computer program, the computer program comprising instructions which, when executed by said processing unit, cause the node to perform the steps of the method as claimed in any one of claims 4 to 8 and any one of claims 9 to 12 as dependent thereon.

[0078] According to a sixth aspect, there is provided a computer readable medium having stored thereon a computer program, the computer program comprising instructions which, when the program is executed by a computer, cause the computer to perform the steps of any embodiment of the method as described in this document.

[0079] The working, advantages and embodiments of the UE, the mobile network node, the method for causing the UE to perform a RA procedure in a cell of a gNB, and the working, advantages and embodiments of the computer-readable medium correspond to the working, advantages and embodiments of the method for performing a RA (random access) procedure by a UE (user equipment) in a cell of a gNB as described in this document, after necessary modifications. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] For a more complete understanding of the present invention, reference is made to the accompanying drawings in the following description, in which:

[0081] Figure 1 A schematic diagram showing a use case involving a UE, a gNB and three cells of the gNB;

[0082] Figure 2 A schematic diagram of a UE according to one or more embodiments of the present invention is shown;

[0083] Figure 3 A schematic diagram of a network node (gNB) according to one or more embodiments of the present invention is shown;

[0084] Figure 4 A schematic diagram showing a method for performing an RA process executed in a UE according to one or more embodiments of the present invention; and

[0085] Figure 5 A schematic diagram showing a method for enabling a UE to perform a RA procedure, performed in a gNB, according to one or more embodiments of the present invention; DETAILED DESCRIPTION

[0086] Figure 1 A schematic diagram of an exemplary use case involving a UE 100, a gNB 110, and three cells 120, 130, and 140 of the gNB is shown. Cell 120 may be a primary PCell for UE 100. Cells 130 and 140 may be SCells and / or secondary PCells. Typically, a PCell of a first UE may also be used as an SCell for a second UE.

[0087] In one or more embodiments, UE 100 may be a vehicle, such as a car, motorcycle, van, truck, bicycle, or scooter.

[0088] Figure 2A schematic diagram of a UE 100 according to one or more embodiments of the present invention is shown, the UE being arranged to perform a RA (random access) procedure in a cell of a gNB 110. The UE 100 comprises at least one or more transceivers 210 for communicating with the gNB using one or more PCells and / or SCells of the gNB 110. It further comprises a processing unit 220 for executing the steps of a computer program stored on a computer readable medium 230. The computer program comprises instructions which, when executed by the processing unit 220, cause the UE 100 to perform the following steps with reference to Figure 4 The steps of method 400 are described.

[0089] Figure 3 A schematic diagram of a network node or gNB 110 is shown, which is arranged to enable a UE 100 to perform a RA procedure in a cell of the gNB 110. In this document, the network node is a gNB, but it can also be a different type of node, such as a 3G or 4G base station.

[0090] The gNB 110 comprises one or more transceivers 310 for communicating with the UE 100 using one or more PCells and / or SCells of the node. It further comprises a processing unit 320 for executing the steps of a computer program stored on a computer readable medium 330. The computer program comprises instructions which, when executed by the processing unit 320, cause the gNB 110 to perform the following steps with reference to Figure 5 The steps of method 500 are described.

[0091] refer to Figure 1 and Figure 4 , the following steps of the method 400 (preferably performed by the UE 100) will be described:

[0092] Step 410: Receive first data about the main PCell 120 from the gNB 110, where the first data is used to configure the main PCell 120.

[0093] In one or more embodiments, the first data includes information about BWP (Bandwidth Path) and / or information about RACH resource configuration and / or PUCCH (Physical Uplink Control Channel) resource configuration). Typically, the UE may be arranged to transmit information about RACH and / or PUCCH resources when available.

[0094] Step 420: Activate the primary PCell 120 based on the first data.

[0095] In one or more embodiments, the method 400 may further include step 422: using the activated primary PCell 120, receiving fourth data about one or more SCells 130, 140 allocated to the primary PCell 120 from the gNB, the fourth data being used to configure the one or more SCells; and step 425: based on the fourth data, activating the one or more SCells 130, 140 allocated to the primary PCell 120. The activated SCell may be used as an additional radio resource for the UE 100.

[0096] Step 430: Using the activated primary PCell 120, receive second data about one or more secondary PCells 130, 140 from the gNB 110, the second data being used for (i) configuring the one or more secondary PCells 130, 140, and for (ii) performing a RA process in the one or more secondary PCells 130, 140, and optionally for (iii) performing a RACH (random access channel) process in the activated secondary PCell.

[0097] In one or more embodiments, the second data includes information about a BWP (Bandwidth Path) and / or information about a RACH resource configuration for each of one or more secondary PCells 130, 140 and an index number identifying the secondary PCell. The second data may further include information about a PUCCH (Physical Uplink Control Channel) resource configuration. In one or more embodiments, the first data and / or the second data are received by the UE 100 (and thus sent by the gNB 110) as RRC (Radio Resource Control) information.

[0098] Examples of RRC information that may include the second data are presented in the following table:

[0099]

[0100] exist Figure 1 In the embodiment, only secondary PCells 130 and 140 are indicated, but gNB 110 may send second data about more secondary PCells (e.g., secondary PCells SP3 and SP4). For each secondary PCell in Table 1, an index number n is provided. In addition, for each secondary PCell, corresponding BWP information BWPn and RACH resource configuration RAn are provided.

[0101] Step 440: Receive third data from the gNB 110, the third data indicating which of the one or more secondary PCells 130, 140 is to be activated. The third data may be sent and received periodically or according to a predetermined time interval.

[0102] In one or more embodiments, the third data includes an index number of the secondary PCell to be activated. Since the UE 100 may have acquired all relevant information for activating the selected PCell from the second data, the third data only needs to include the index number.

[0103] In one or more embodiments, the third data is included in a MAC CE header of information sent by the gNB 110 and received by the UE 100. For example, when the gNB has determined that the secondary PCell 130 will be activated by the UE 100 when the primary PCell 120 is turned off, the MAC CE may indicate 00000001 to the UE 100.

[0104] An example of MAC CE information that may include third data is presented below as octets:

[0105] SP8 SP7 SP6 SP5 SP4 SP3 SP2 SP1 0 0 0 0 0 0 0 1

[0106] In one or more embodiments, the third data may include a scheme indicating when which of the multiple secondary PCells will be activated in the upcoming period. In this case, the third data may include multiple instances of the MAC CE information as indicated above, wherein, for each instance, the information indicates when the secondary PCell indicated in the MAC CE information will be activated.

[0107] Step 450: Determine that the primary PCell 120 is turned off;

[0108] In one or more embodiments, the gNB 110 sends information about the shutdown period of the primary PCell 120 to the UE 100. The UE 100 can then determine that the primary PCell 120 is shut down based on the received information. In one or more embodiments, RRC signaling can be used to transmit this information. In this case, the transmission can be semi-static. In one or more other embodiments, DCI (downlink control information) signaling can be used to transmit this information. In this case, the transmission can be dynamic.

[0109] The information about the shut-down period may be based on a power saving plan indicating which PCell will be shut down and when in an upcoming time period.

[0110] In another embodiment, the UE 100 may determine that the primary PCell 120 is turned off based on a signal loss of the primary PCell 120 .

[0111] Step 460: activating the indicated secondary PCell 130 based on the second data and the third data;

[0112] In one or more embodiments, the method 400 may further include step 462: using the activated secondary PCell 130, receiving fifth data about one or more SCells 140 allocated to the secondary PCell 130 from the gNB, the fifth data being used to configure the one or more SCells 140; and step 465: based on the fifth data, activating the one or more SCells 140 allocated to the secondary PCell 130. Also, in this case, the activated SCell may be used as an additional radio resource of the UE 100.

[0113] Step 470: Perform a RA process in the activated secondary PCell 130 based on the second data.

[0114] Since the UE 100 has activated the new PCell 130, it can perform the RA procedure in this PCell whenever needed while reducing delay and latency.

[0115] In one or more embodiments, the method 400 may further include step 480: after determining that the shutdown period ends, reactivating the main PCell 120 and deactivating the secondary PCell 130, and optionally, reactivating the SCells 130, 140 assigned to the main PCell 120 and deactivating the one or more SCells 140 assigned to the secondary PCell 130.

[0116] In one or more embodiments, the UE 100 may determine that the primary PCell 120 is turned on again based on the received information about the off period of the primary PCell 120 .

[0117] refer to Figure 1 and Figure 5 , the following steps of method 500 for enabling a UE to perform an RA procedure in a cell of a gNB (next generation Node B) of a mobile network will be described, and method 500 will be performed by gNB 110. The steps of method 400 are obtained by mirroring the steps of method 500.

[0118] Step 510: Send first data about a primary PCell to a UE, where the first data is used to configure the primary PCell;

[0119] In one or more embodiments, the method 500 may further include step 512 : using the activated primary PCell 120 , sending fourth data about one or more SCells 130 , 140 allocated to the primary PCell 120 to the UE 100 , the fourth data being used to configure the one or more SCells 130 , 140 .

[0120] In one or more embodiments, the method 500 may further include step 515 of selecting one or more secondary PCells 130, 140 from the one or more SCells 130, 140 assigned to the primary PCell, preferably based on a predetermined traffic volume threshold. It can be said that SCells with traffic volume below a predetermined amount have sufficient capacity to take over the role of the primary PCell of the UE 100.

[0121] Step 520: Send second data about one or more secondary PCells to the UE, where the second data is used for (i) configuring the one or more secondary PCells and for (ii) performing a RA process in the one or more secondary PCells.

[0122] It can be understood that when the old PCell 120 is turned off, the one or more secondary PCells 130 , 140 for which the second data is transmitted are possible or alternative new PCells for the UE 100 .

[0123] In one or more embodiments, the second data may be sent to the UE periodically. In one or more embodiments, the second data may be sent to the UE together with the first data.

[0124] Step 530: Determine that the primary PCell is to be shut down;

[0125] The gNB 110 may determine that the primary PCell 120 needs to be shut down, for example to reduce power consumption of the gNB 110, which may be based on information provided by other entities in the network.

[0126] In one or more embodiments, the method 500 may further include step 535: determining that the primary PCell is to be turned off during a turn-off period, the turn-off period starting at a turn-off time; and sending information about the turn-off period and / or the turn-off time to the UE.

[0127] In one or more embodiments, step 530 includes establishing a power saving plan that indicates which PCell will be shut down and when in an upcoming time period. The power saving plan may be determined by the gNB or by another entity in the communication network of which the gNB is a part.

[0128] In one or more embodiments, the sending of the second data to the UE may be triggered by determining that the primary PCell is to be shut down. In this case, step 530 may precede step 520.

[0129] Step 540: When the primary PCell 120 is deactivated, determining which secondary PCell of the one or more secondary PCells 130, 140 will be activated by the UE 100;

[0130] In one or more embodiments, step 540 may include determining a scheme indicating when which of the plurality of secondary PCells is to be activated within the upcoming time period based on the energy saving plan.

[0131] In one or more embodiments, the gNB 110 determines which of the one or more secondary PCells is to be activated based on a comparison of the traffic volumes of the one or more secondary PCells and / or based on a comparison of the signal strengths of the one or more secondary PCells. For example, the PCell with the smallest traffic volume may be considered to have the greatest capability for taking over the role of the new PCell for the UE 100 and may therefore be determined as the secondary PCell that the UE 100 should activate when its signal strength is above a predetermined threshold.

[0132] Step 550: Send third data indicating the determined secondary PCell to the UE;

[0133] In one or more embodiments, the third data includes the scheme indicating when which secondary PCell among the plurality of secondary PCells will be activated in an upcoming time period.

[0134] In one or more embodiments, step 540 and / or step 550 are triggered by step 530. In other embodiments, step 540 and / or step 550 are performed periodically.

[0135] Step 560: Turn off the main PCell.

[0136] In one or more embodiments, the primary PCell 120 is turned off at the above-mentioned turn-off time, and the turn-off duration is equal to the turn-off period.

[0137] In one or more embodiments, the method 500 further comprises step 565 : using the activated secondary PCell 130 , sending fifth data about one or more SCells 140 allocated to the secondary PCell to the UE 100 , the fifth data being used to configure the one or more SCells 140 .

[0138] In one or more embodiments, the method 500 further comprises step 570: turning on the primary PCell. In one or more embodiments, after the above-mentioned shutdown period ends, the primary PCell 120 is turned on again.

[0139] The formats and contents of the first data, second data, third data, fourth data and fifth data in the embodiment of method 500 are respectively the same as the formats and contents of the first data, second data, third data, fourth data and fifth data in the embodiment of method 400 .

[0140] Typically, the first data, the fourth data, and the fifth data may be included in the RRC (Radio Resource Control) information and / or transmitted together as the sixth data. The second data may be included in the RCC information or the MAC CE (Media Access Control Element) information. The third data may be included in the MAC CE information or the RCC information. Typically, the second data and the third data may be transmitted together as the seventh data.

[0141] The first data and / or the second data and / or the fourth data may be sent by the gNB 110 to the UE 100 together as a single RRC message.

[0142] The technician will appreciate that the various illustrative logic blocks, modules, circuits and algorithmic steps described about the embodiments disclosed herein can be implemented as electronic hardware, computer software or the combination of the two. In order to clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits and steps have been generally described above with regard to their functions. Whether this function is implemented as hardware or software depends on specific applications and design constraints imposed on the entire system. Those skilled in the art can implement described functions in different ways for each specific application, but this implementation decision should not be interpreted as causing deviation from the scope of the invention.

[0143] The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is to be given the widest scope consistent with the principles and novel features disclosed herein.

[0144] The benefits and advantages that the present invention can provide have been described above with respect to specific embodiments. These benefits and advantages, as well as any elements or limitations that can make them occur or become more significant, should not be interpreted as key, necessary or essential features of any or all claims. As used herein, the term "comprises / comprising" or any other variation thereof is intended to be interpreted as non-exclusively including the elements or limitations following these terms. Accordingly, a system, method or other embodiment including a set of elements is not limited to these elements, and may include other elements that are not explicitly listed or inherent to the claimed embodiments.

[0145] Although the present invention has been described with reference to specific embodiments, it should be understood that these embodiments are illustrative and the scope of the present invention is not limited to these embodiments. Many changes, modifications, additions and improvements to the above-described embodiments are possible. It is contemplated that these changes, modifications, additions and improvements fall within the scope of the present invention as detailed in the following claims.

Claims

1. A method for performing a RA (Random Access) procedure by a UE (User Equipment) in a cell of a gNB (Next Generation Node B) of a mobile network, the method comprising the following steps: receiving first data about a primary PCell (primary cell) from a gNB, where the first data is used to configure the primary PCell; Based on the first data, activating the primary PCell; Using the activated primary PCell, receiving second data about one or more secondary PCells from the gNB, the second data being used for (i) configuring the one or more secondary PCells and for (ii) performing a RA procedure in the one or more secondary PCells; receiving third data from the gNB, the third data indicating which secondary PCell of the one or more secondary PCells is to be activated; Determining that the primary PCell is shut down; activating an indicated secondary PCell based on the second data and the third data; as well as Based on the second data, a RA procedure is performed in the activated secondary PCell, and optionally a RACH (Random Access Channel) procedure is performed in the activated secondary PCell.

2. The method according to claim 1, further comprising the steps of: Using the activated primary PCell, receiving fourth data about one or more SCells allocated to the secondary PCell from the gNB, the fourth data being used to configure the one or more SCells; Based on the fourth data, activate one or more SCells allocated to the primary PCell; and / or, Using the activated secondary PCell, receiving fifth data about one or more SCells allocated to the secondary PCell from the gNB, the fifth data being used to configure the one or more SCells; Based on the fifth data, one or more SCells allocated to the secondary PCell are activated.

3. The method according to claim 1 or 2, further comprising the following steps: Receiving information about a shutdown period of the primary PCell; Determining based on the received information that the primary PCell is turned off; and optionally, After determining that the shutdown period ends, the primary PCell is reactivated and the secondary PCell is deactivated, and optionally, the SCell allocated to the primary PCell is reactivated and the SCell allocated to the secondary PCell is deactivated.

4. A method for causing a UE to perform a RA procedure in a cell of a gNB (next generation Node B) of a mobile network, comprising the following steps: Sending first data about a primary PCell to a UE, where the first data is used to configure the primary PCell; Sending second data about one or more secondary PCells to the UE, the second data being used for (i) configuring the one or more secondary PCells and for (ii) performing a RA procedure in the one or more secondary PCells; Determining that the primary PCell is to be shut down; When the primary PCell is deactivated, determining which secondary PCell of the one or more secondary PCells is to be activated by the UE; sending third data indicating the determined secondary PCell to the UE; The master PCell is turned off.

5. The method according to claim 4, further comprising the steps of: Determining that the primary PCell is to be turned off during a turn-off period, the turn-off period starting at a turn-off time; Sending information about the shutdown period and / or the shutdown time to the UE; and optionally, After the shutdown period ends, turning on the primary PCell; and / or Establishing a power saving plan that indicates which PCell will be shut down and when during an upcoming time period; determining, based on the energy saving plan, a scheme indicating when which of the plurality of secondary PCells will be activated in the upcoming time period; Wherein, the third data includes the scheme.

6. The method according to claim 4 or 5, further comprising the following steps: Using the activated primary PCell, sending fourth data about one or more SCells allocated to the primary PCell to the UE, where the fourth data is used to configure the one or more SCells; and / or, Using the activated secondary PCell, fifth data on one or more SCells allocated to the secondary PCell is sent to the UE, where the fifth data is used to configure the one or more SCells.

7. The method according to claim 6, further comprising the steps of: The one or more secondary PCells are preferably selected from one or more SCells allocated to the primary PCell based on a predetermined traffic volume threshold.

8. The method according to any one of claims 4 to 7, wherein: Determining which one of the one or more secondary PCells is to be activated is based on a comparison of traffic volumes of the one or more secondary PCells and / or a comparison of signal strengths of the one or more secondary PCells.

9. A method according to any one of the preceding claims, wherein: The second data about one or more secondary PCells includes, for each of the PCells, information about an index number identifying the secondary PCell, information about a BWP (Bandwidth Path), and / or information about a RACH resource configuration.

10. A method according to any one of the preceding claims, wherein: The first data, the fourth data and the fifth data are included in RRC (Radio Resource Control) information; and / or, The second data is included in RCC information or MAC CE (Media Access Control Element) information; and / or, The third data is included in MAC CE information or RCC information.

11. A method according to any one of the preceding claims, wherein: The first data and / or the second data and / or the fourth data are sent by the gNB to the UE together as a single RRC message.

12. A UE (User Equipment) arranged to perform a RA procedure in a cell of a gNB of a mobile network; comprising: one or more transceivers configured to communicate with the gNB using one or more PCells and / or SCells of the gNB; a processor for executing the steps of a computer program; A computer-readable medium having a computer program stored thereon, the computer program comprising instructions which, when executed by the processing unit, cause the UE to perform the steps of the method as claimed in any one of claims 1 to 3 and any one of claims 9 to 11 as dependent upon any one of claims 1 to 3.

13. A mobile network node, preferably a gNB, arranged to cause a UE to perform a RA procedure in a cell of the node, comprising: one or more transceivers configured to communicate with the UE using one or more PCells and / or SCells of the node; a processor for executing the steps of a computer program; A computer readable medium having stored thereon a computer program, the computer program comprising instructions which, when executed by the processing unit, cause the network node to perform the steps of the method as claimed in any one of claims 4 to 8 and any one of claims 9 to 12 as dependent thereon.

14. A computer readable medium having stored thereon a computer program, the computer program comprising instructions which, when the program is executed by a computer, cause the computer to perform the steps of the method as claimed in any one of claims 1 to 11.

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