Method and device for realizing synchronization

Abstract

Apparatuses and methods for implementing synchronization are provided. The solution comprises: receiving (300) a random access indication message from a network entity, the random access indication message indicating whether transmission of at least one physical random access channel (PRACH) uses at least one random access resource corresponding to or associated with one or more network entities; and transmitting (302) the at least one PRACH based on the random access indication message.

Description

Technical Field

[0001] The exemplary and non-limiting embodiments of the present invention generally relate to wireless communication systems. In particular, the embodiments of the present invention relate to apparatus and methods in wireless communication networks. Background Art

[0002] Wireless communication systems are constantly evolving. The systems are being developed so that new services can be provided to users of the systems. On the other hand, the systems are also being developed so that the systems can operate more efficiently by increasing capacity, connection quality and reducing energy consumption and delays.

[0003] In modern wireless communication systems, solutions have been developed in which a terminal device can communicate with more than one transmission reception point or is aware of multiple transmission reception points.

[0004] Terminal devices that communicate with a transmission reception point need to be synchronized with the transmission point. When a terminal device is associated with more than one transmission reception point, it may cause problems if synchronization is lost. Summary of the invention

[0005] The following is a simplified summary of the present invention in order to provide a basic understanding of some aspects of the present invention. This summary is not an exhaustive overview of the present invention, and it is not intended to identify the key / critical elements of the present invention or to delineate the scope of the present invention. Its sole purpose is to present some concepts of the present invention in a simplified form as a prelude to the more detailed description presented later.

[0006] According to one aspect of the present invention, a method for a terminal device is provided, comprising: receiving a random access indication message from a network entity, the random access indication message indicating whether the transmission of at least one physical random access channel PRACH uses at least one random access resource corresponding to or associated with one or more network entities; and sending at least one PRACH based on the random access indication message.

[0007] In an embodiment, the method comprises receiving a random access indication message in downlink control information DCI.

[0008] In an embodiment, the transmitted at least one PRACH uses one or more of the at least one random access resource.

[0009] In an embodiment, the random access resource includes at least one of the following: a random access preamble code index, a synchronization signal / physical broadcast channel SS / PBCH index, and a random access channel opportunity.

[0010] In an embodiment, the random access indication message includes at least one second random access resource for contention-free random access corresponding to or associated with one or more network entities.

[0011] According to one aspect of the present invention, a method for a network entity is provided, comprising: obtaining a random access indication message; sending a random access indication message to a terminal device, wherein the random access indication message indicates whether transmission of at least one physical random access channel PRACH uses at least one random access resource corresponding to or associated with one or more network entities.

[0012] According to one aspect of the present invention, there is provided an apparatus in a terminal device, comprising: at least one transceiver, wherein the at least one transceiver is configured to: receive a random access indication message from a network entity, the random access indication message indicating whether the transmission of at least one physical random access channel PRACH uses at least one random access resource corresponding to or associated with one or more network entities; and send at least one PRACH based on the random access indication message.

[0013] According to one aspect of the present invention, there is provided an apparatus in a network element, comprising: at least one processor; and at least one transceiver, wherein the at least one processor is configured to: obtain a random access indication message; wherein the transceiver is configured to: send the random access indication message to a terminal device, wherein the random access indication message indicates whether the transmission of at least one physical random access channel PRACH uses at least one random access resource corresponding to or associated with one or more network entities.

[0014] According to one aspect of the present invention, a computer program is provided, comprising instructions for causing a device to perform at least the following items: receiving a random access indication message from a network entity, the random access indication message indicating whether the transmission of at least one physical random access channel PRACH uses at least one random access resource corresponding to or associated with one or more network entities; and sending at least one PRACH based on the random access indication message.

[0015] According to one aspect of the present invention, a computer program is provided, comprising instructions for causing an apparatus to at least perform the following items: obtaining a random access indication message; sending the random access indication message to a terminal device, wherein the random access indication message indicates whether the transmission of at least one physical random access channel PRACH uses at least one random access resource corresponding to or associated with one or more network entities.

[0016] An embodiment provides a computer-readable storage medium comprising program instructions for causing a device to perform at least the following items: receiving a random access indication message from a network entity, wherein the random access indication message indicates whether the transmission of at least one physical random access channel PRACH uses at least one random access resource corresponding to or associated with one or more network entities; and sending at least one PRACH based on the random access indication message.

[0017] An embodiment provides a computer-readable storage medium, comprising program instructions for causing an apparatus to perform at least the following items: obtaining a random access indication message; sending the random access indication message to a terminal device, wherein the random access indication message indicates whether the transmission of at least one physical random access channel PRACH uses at least one random access resource corresponding to or associated with one or more network entities.

[0018] An embodiment provides a device, comprising: a component for receiving a random access indication message from a network entity, wherein the random access indication message indicates whether the transmission of at least one physical random access channel PRACH uses at least one random access resource corresponding to or associated with one or more network entities; and a component for sending at least one PRACH based on the random access indication message.

[0019] An embodiment provides an apparatus comprising: a component for obtaining a random access indication message and sending the random access indication message to a terminal device, wherein the random access indication message indicates whether the transmission of at least one physical random access channel PRACH uses at least one random access resource corresponding to or associated with one or more network entities.

[0020] One or more examples of implementation are described in more detail in the drawings and the following description. Other features will be apparent from the description and drawings, as well as from the claims. The embodiments and / or examples and features described in this specification that do not fall within the scope of the independent claims will be interpreted as examples that can be used to understand the various embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Embodiments of the present invention are described below by way of example only with reference to the accompanying drawings, in which

[0022] Figure 1 An example of a simplified system architecture for a communication system is shown;

[0023] Figure 2 An example of a multiple transmission reception point (M-TRP) case is shown;

[0024] Figure 3A is a flow chart illustrating an embodiment;

[0025] Figure 3B is a flow chart illustrating an embodiment;

[0026] Figure 4A is a signaling diagram illustrating an embodiment;

[0027] Figure 4B is a signaling diagram illustrating an embodiment;

[0028] Figure 5 An example of an apparatus is shown;

[0029] Fig. 6A An example of an apparatus is shown; and

[0030] Figure 6B An example of an apparatus is shown. DETAILED DESCRIPTION

[0031] The following embodiments are presented as examples only. Although the specification may refer to "one", "an" or "some" embodiments and / or examples in several places of the text, this does not necessarily mean that each reference is made to the same embodiment or example, or that a particular feature applies only to a single embodiment and / or example. Individual features of different embodiments and / or examples may also be combined to provide other embodiments and / or examples.

[0032] In the following, different exemplary embodiments will be described using the following architecture as an example of an access architecture to which the embodiments may be applied, without limiting the embodiments to such architectures: a radio access architecture based on Long Term Evolution (LTE) or a new radio (NR) of the fifth generation technology standard for broadband cellular networks (5G). It is apparent to those skilled in the art that the embodiments may also be applied to other kinds of communication networks with appropriate devices by appropriately adjusting the parameters and processes. Some examples of other options for suitable systems are Universal Mobile Telecommunications System (UMTS) Radio Access Network (UTRAN or E-UTRAN), Long Term Evolution (LTE, the same as E-UTRA), Wireless Local Area Network (WLAN or WiFi), Worldwide Interoperability for Microwave Access (WiMAX), Bluetooth, Personal Communications Service (PCS), ZigBee, Wideband Code Division Multiple Access (WCDMA), systems using Ultra Wideband (UWB) technology, sensor networks, mobile ad hoc networks (MANETs), and Internet Protocol Multimedia Subsystems (IMS) or any combination thereof.

[0033] Figure 1 An example of a simplified system architecture is depicted, showing only some elements and functional entities, all of which are logical units, the implementation of which may differ from what is illustrated. Figure 1The connections shown in are logical connections; the actual physical connections may be different. It is obvious to those skilled in the art that the system typically also includes Figure 1 The functions and structures are different from those shown.

[0034] However, the embodiments are not limited to the systems given as examples, but a person skilled in the art may apply the solution to other communication systems having the necessary properties.

[0035] Figure 1 The example of FIG. 1 shows a portion of an exemplary wireless access network.

[0036] Figure 1 User equipment 100 and 102 are shown configured to wirelessly connect to an access node (such as an (e / g) Node B) 104 providing the cell over one or more communication channels in the cell. The physical link from the user equipment to the eNodeB or gNB is called an uplink or reverse link, and the physical link from the eNodeB or gNB to the user equipment is called a downlink or forward link. It should be understood that the eNodeB or gNB or its functions can be implemented using any node, host, server or access point entity suitable for such use.

[0037] The user devices 100 and 102 in the present disclosure may be referred to as user equipment. The user equipment may be a terminal device that may be used or integrated in any kind of equipment.

[0038] The communication system typically includes more than one eNodeB or gNB, in which case the eNodeB or gNB may also be configured to communicate with each other via wired or wireless links designed for the purpose. These links may be used for signaling purposes. An eNodeB or gNB is a communication device configured to control the radio resources of the communication system to which it is coupled. A NodeB may also be referred to as a base station, an access point, or any other type of interface device, including a relay station capable of operating in a wireless environment. An eNodeB or gNB includes or is coupled to a transceiver. A connection is provided from the transceiver of the eNodeB or gNB to an antenna unit that establishes a bidirectional radio link to a user equipment. The antenna unit may include multiple antennas or antenna elements. The eNodeB or gNB is also connected to a core network 110 (CN or next generation core NGC). Depending on the system, the counterpart on the CN side may be a serving gateway (S-GW, routing and forwarding user data packets), a packet data network gateway (P-GW), for providing a connection for a user equipment (UE) to an external packet data network or a mobile management entity (MME), etc.

[0039] User equipment (also referred to as UE, user equipment, user terminal, terminal device, etc.) shows a type of device to which resources on the air interface are allocated and assigned, so any features of the user equipment described herein can be implemented using corresponding devices (such as relay nodes). An example of such a relay node is a layer 3 relay (self-backhaul relay) towards a base station.

[0040] User equipment generally refers to portable communication devices including wireless mobile communication devices operating with or without a Subscriber Identity Module (SIM), including but not limited to the following types of devices: mobile stations (mobile phones), smart phones, personal digital assistants (PDAs), mobile phones, devices using wireless modems (alarm or measuring equipment, etc.), laptop computers and / or touch screen computers, tablet computers, game consoles, vehicles, notebooks and multimedia devices.

[0041] It should be understood that a user device may also be almost exclusively an uplink-only device, an example of which is a camera or video camera that loads images or video clips to a network. A user device may also be a device with the ability to operate in an Internet of Things (IoT) network, which is a scenario in which objects are provided with the ability to transmit data over a network without the need for human-to-human or human-to-computer interaction. A user device (or in some embodiments, a layer 3 relay node) is configured to perform one or more of the user equipment functions. A user device may also be referred to as a subscriber unit, a mobile station, a remote terminal, an access terminal, a user terminal, or a user equipment (UE), just to name a few names or devices.

[0042] The various techniques described herein may also be applied to cyber-physical systems (CPS) (systems of computing elements that collaboratively control physical entities). CPS can enable the implementation and utilization of a large number of interconnected ICT devices (sensors, actuators, processor microcontrollers, etc.) embedded in physical objects at different locations. Mobile cyber-physical systems, in which the physical systems in question have inherent mobility, are a subcategory of cyber-physical systems. Examples of mobile physical systems include mobile robots and electronic devices transported by humans or animals.

[0043] It should be understood that Figure 1 In the figure, for the sake of clarity only, the user equipment is depicted as comprising 2 antennas. The number of receiving and / or transmitting antennas may naturally vary depending on the current implementation.

[0044] Additionally, although the apparatus has been depicted as a single entity, different units, processors and / or memory units ( Figure 1 ) can be implemented.

[0045] It will be apparent to those skilled in the art that the depicted system is merely an example of a portion of a radio access system, and in practice the system may include multiple eNodeBs or gNBs, user equipment may have access to multiple radio cells, and the system may also include other devices such as physical layer relay nodes or other network elements.

[0046] As mentioned above, solutions have been developed where a terminal device can communicate with more than one transmission reception point or be aware of multiple transmission reception points TRPs. A TRP can be, for example, an access node (eNode B, gNode B), a remote radio head or a remote distributed unit.

[0047] Figure 2 An example of a multiple transmission reception point (M-TRP) situation is shown. In the figure, there are two transmission reception points TRP0 200 and TRP1 202 and a terminal device 204. Figure 2 In the example of M-TRP of FIG. 2 , there are two TRPs, but the number of TRPs is not limited to two TRPs. TRP0 200 transmits two beams 206A, 206B with channel state information-reference signals CSI-RS#1 and CSI-RS#2. TRP1 202 transmits two beams 208A, 208B with channel state information-reference signals CSI-RS#3 and CSI-RS#4.

[0048] In an embodiment, TRP0 operates a first cell with a physical cell ID PCI#0, and TRP1 operates a second cell with a physical cell ID PCI#1. For example, the terminal device 204 may be connected to a radio resource control RRC with TRP0 200. TRP1 202 does not have an RRC connection with the terminal device, but is sending a physical downlink control channel PDCCH, which may be associated with downlink control information (DCI), to the terminal device. The cell PCI#0 of TRP0 may be represented as a serving cell, and the cell PCI#1 of TRP1 may be represented as an inter-cell mTRP cell or a cell configured for inter-cell multi-TRP communication of UEs. In some cases, the cell PCI#1 of TRP1 may be referred to as a "non-serving cell". However, the M-TRP configuration of PCI#1 or a non-serving cell is still part of the serving cell configuration (PCI#0).

[0049] In an embodiment, M-TRP operation may be implemented in such a way that there may be different control resource sets CORESETs associated with a particular TRP using the CORESETPoolIndex parameter. Multiple CORESETs associated with TRP0 may have been given a poolIndex (e.g., CORESETPoolIndex#0), and multiple CORESETs associated with TRP1 may have been given a different poolIndex (e.g., CORESETPoolIndex#1). Therefore, in some embodiments, in order to determine whether multi-TRP communication is configured, the UE may determine whether there are more than one (e.g., two or more) different CORESETpoolIndex values ​​configured for a CORESET.

[0050] If a terminal device in a connected state has been inactive, i.e. not performing any uplink transmissions, for a certain time, synchronization to the network may be lost. If the network detects such a loss of uplink synchronization, it may trigger a random access transmission from the terminal device via a so-called Physical Downlink Control Channel, PDCCH, command. The PDCCH command may be provided using Downlink Control Information, DCI.

[0051] The PDCCH order may trigger a contention-free random access CFRA procedure or a contention-based random access CBRA procedure. The DCI may carry an indication whether CFRA or CBRA should be used.

[0052] In order to acquire synchronization with the network, the terminal device may adjust the timing advance TA of its transmissions. TA may depend on the distance of the terminal device to the serving base station or the propagation delay between the terminal device and the base station.

[0053] In the case where a terminal device is involved in multiple TRPs, applying a single TA does not enable it to communicate with more than one TRP. Due to the possible differences in propagation delay between TRPs (both for inter-cell and intra-cell multiple TRPs) and the possible differences in synchronization accuracy between TRPs, if a single TA is used, it may not be possible to ensure that uplink signals from terminal devices toward different TRPs are within the length of the cyclic prefix. Therefore, relying on a single TA for uplink transmissions toward different TRPs may not be sufficient. The use of a single TA may result in uplink performance degradation due to, for example, inter-symbol interference.

[0054] Therefore, multiple TAs may be required for multi-TRP operation of terminal devices, and an efficient solution that can acquire and use multiple TAs is needed.

[0055] Figure 3AThe flowchart of shows an embodiment. The flowchart illustrates an example of the operation of the apparatus. In an embodiment, the apparatus may be a terminal device, a user equipment, a part of a terminal device or any other apparatus capable of performing the following steps.

[0056] In step 300, the apparatus is configured to receive a random access indication message from a network entity, the random access indication message indicating whether transmission of at least one physical random access channel PRACH uses at least one random access resource corresponding to or associated with one or more network entities.

[0057] In step 302, the apparatus is configured to send at least one PRACH based on a random access indication message.

[0058] In an embodiment, the terminal device may receive the random access indication message in downlink control information DCI. In an embodiment, the random access indication message may also be received via a medium access control MAC control element CE or via RRC.

[0059] The network entity may be a TRP or a physical cell. For example, receiving from a network entity may include: receiving from a transmission reception point, receiving from a physical cell, receiving from a control resource set group, or a control resource set pool index. The network entity may also be represented by a set of transmission configuration indicator TCI states or a set of reference signals (such as SSB and / or CSI-RS).

[0060] Figure 3B The flowchart of the embodiment is shown. The flowchart illustrates an example of the operation of the device. In an embodiment, the device can be a network entity, a TRP, an access point, a physical cell, a gNB, a control resource set group. The device can also be a part of a network entity, a TRP, an access point or a gNB or any other device. The device can perform the following steps.

[0061] In step 310, the apparatus is configured to obtain a random access indication message.

[0062] In step 312, the apparatus is configured to send a random access indication message to the terminal device, wherein the random access indication message indicates whether transmission of at least one physical random access channel PRACH uses at least one random access resource corresponding to or associated with one or more network entities.

[0063] In the following, the term TRP may refer to a network entity. However, as is well known to those skilled in the art, the term network entity may be replaced with, for example, a physical cell, a gNB, or a control resource set group or a control resource set pool index.

[0064] In an embodiment, the DCI may indicate that the terminal device is to perform a contention-free random access (CFRA) procedure or a contention-based random access (CBRA) procedure.

[0065] In an embodiment, the DCI may contain at least one information element to provide an indication of whether the terminal device should use random access channel RACH resources (RACH timing and / or preamble) corresponding to or associated with a given TRP to send PRACH. Thus, a single PRACH may be sent.

[0066] In an embodiment, the DCI may include at least one information element to provide an indication of whether the terminal device should use RACH resources (such as RACH opportunities and / or preambles) corresponding to or associated with more than one TRP to send PRACH. Therefore, more than one PRACH may be sent.

[0067] For a contention-free random access CFRA where the DCI indicates that the terminal device will transmit two PRACHs, the terminal device may determine that the DCI also includes (in addition to the first random access preamble index, the first synchronization signal / physical broadcast channel SS / PBCH index and (multiple) first random access channel opportunities) additional random access preamble indexes for more than one transmission, such as (multiple) second preamble indexes, additional SS / PBCH indexes, such as the second SS / PBCH index, and additional random access channel opportunities, such as (multiple) second random access channel opportunities. Thus, the terminal device may determine the presence of other preamble indices, synchronization signal block SSB indices and random access opportunities in the DCI.

[0068] Note that reserved or existing bits / entries in the DCI may be used to carry an indication of a second preamble index, a second SSB index and / or a second random access channel opportunity.

[0069] It should also be noted that the (multiple) second random access channel opportunities, which may be one or more opportunities, may not be explicitly indicated in the DCI, but the terminal device may determine them based on the indicated (multiple) first random access channel opportunities using some pre-configured rules or associations between the (multiple) first and (multiple) second random access channel opportunities (corresponding to the first and second TRPs).

[0070] Note also that indications of first and second parameters from the above-mentioned first and second sets of parameters may be carried using a code point that may indicate two entries (eg, first random access channel opportunity(s) and second random access channel opportunity(s).

[0071] For contention-based random access CBRA in which the indication indicates that the terminal device is to transmit a PRACH, the terminal device may indicate the RACH resources of a TRP among the multiple TRPs to be used. For example, if the terminal device is configured with RACH resources associated with a first TRP and a second TRP, the terminal device may be indicated via one or more reserved entries / bits in the DCI whether to use the RACH resources associated or corresponding to the first TRP or the second TRP and / or select the SSB associated or corresponding to the first TRP or the second TRP to transmit or restrict it to the RACH resources associated or corresponding to the first TRP or the second TRP and / or select the SSB associated or corresponding to the first TRP or the second TRP. The indication may include a TRP identifier, such as a CORESET pool index or a PCI.

[0072] It may be noted that, as described above, TRP may be represented by a CORESET group (or CORESET pool index) and / or PCI (in the case of multiple TRPs between cells). Therefore, in the above example, TRP may be replaced by a CORESET group ID and / or by a PCI.

[0073] Assume that the terminal device is configured with two TRPs (such as Figure 2 One of the benefits of the above examples is that they allow a PDCCH command sent from a first TRP to trigger a RACH process to the same TRP, to a second TRP, or to both TRPs.

[0074] Reference Figure 2 In the example with two TRPs, there are some options regarding the situation where the received DCI indicates that the terminal device sends PRACH using the RACH resources corresponding to the first TRP or the second TRP.

[0075] First, for inter-cell beam management, based on at least one information element of the received DCI, the "random access preamble index" indicated in the DCI can be associated with a serving cell or a non-serving cell (a non-serving TRP with a PCI different from the serving cell PCI). The association can be determined based on whether the indicated SSB index is associated with the PCI of the serving cell or the PCI of the non-serving cell.

[0076] Secondly, for the intra-cell / inter-cell multiple TRP case, based on at least one information element of the received DCI, the "random access preamble index" indicated in the DCI (if there is only one "random access preamble index" in the DCI) or the corresponding (if there are two "random access preamble indexes" in the DCI) "random access preamble index" can be associated with a CORESET group, for example, CORESETPoolIndex#0 or CORESETPoolIndex#1.

[0077] Further reference to the two TRP Figure 2 For example, there are some options regarding the situation where the received DCI indicates that the terminal device should send PRACH using RACH resources (e.g., RACH timing and / or preamble code) corresponding to two TRPs or associated with two TRPs (or only with a single TRP).

[0078] First, for inter-cell beam management, based on at least one information element of the received DCI, the "random access preamble index" indicated in the DCI can be associated with both the serving cell and the non-serving cell (non-serving TRP having a PCI different from the serving cell PCI).

[0079] Secondly, for intra-cell / inter-cell M-TRP, based on at least one information element of the received DCI, the corresponding "random access preamble index" in the DCI (if there are two "random access preamble indexes" in the DCI) can be associated with two CORESET groups, for example, CORESETPoolIndex#0 and CORESETPoolIndex#1.

[0080] It may also be noted that in the above examples, the second "random access preamble index" or "SS / PBCH index" in the DCI may follow a similar design as the first "random access preamble index" in the DCI.

[0081] It may be further noted that despite the combination Figure 2 The above example is described with reference to two TRP examples, but if there are more than two TRPs, they can be applied in a similar manner.

[0082] Figure 4A is a signaling diagram illustrating an embodiment. The terminal device 204 is configured 400 with two CORESET groups, CORESET group #0 and CORESET group #1. The terminal device is configured with a set of RACH resources (such as RACH opportunities and / or RACH preambles) associated with CORESET group #0 and another set of RACH resources associated with CORESET group #1.

[0083] The terminal device 204 receives a random access indication message 402 from, for example, TRP0. The message may be received as a DCI. The message indicates whether the terminal device 204 is to use resources corresponding to CORESET group #0 or CORESET group #1 or both to send PRACH. In this example, the indication is that PRACH will be sent using resources corresponding to CORESET group #0 and using contention-based random access CBRA.

[0084] The terminal device 204 transmits PRACH based on CBRA by utilizing or restricting the random access resources associated with CORESET group #0. Note that this may mean that the terminal device may restrict itself to selecting (multiple) SSBs corresponding to or associated with the random access resources corresponding to CORESET group #0.

[0085] Figure 4B is a signaling diagram illustrating an embodiment. The terminal device 204 is configured 400 with two CORESET groups, CORESET group #0 and CORESET group #1. The terminal device is configured with one set of RACH resources (RACH opportunities and / or RACH preambles) associated with CORESET group #0 and another set of RACH resources associated with CORESET group #1.

[0086] The terminal device 204 receives a random access indication message 410 from, for example, TRP0. The random access indication message may be received as a DCI, alternatively, the random access indication message may be received via a MAC CE (or even via an RRC). The message indicates whether the terminal device 204 will use resources corresponding to CORESET group #0 or CORESET group #1 or both to send PRACH. In this example, the indication is that PRACH will be sent using resources corresponding to both CORESET group #0 and CORESET group #1. Further, the terminal device is instructed to use contention-free random access CFRA.

[0087] The terminal device 204 determines 412 the presence of a second SSB index and a second preamble index in the DCI.

[0088] The terminal device 204 sends 414 PRACH based on CFRA using resources associated with CORESET group #0 (e.g., the indicated first SSB index and preamble code index), and sends 416 PRACH based on CFRA using resources associated with CORESET group #1 (e.g., the indicated second SSB index and preamble code index).

[0089] In an embodiment, assuming that the terminal device can be configured with two CORESET groups (or PCI, TRP) (for example, CORESET group #0 and CORESET group #1), each CORESET group is associated with a set of RACH resources (such as preamble code index RACH opportunities), for CBRA, the terminal device can be configured to consider the RACH resources associated with the following CORESET groups to send PRACH: the CORESET group to which the CORESET on which the PDCCH command that triggers the RACH process is sent belongs.

[0090] In an embodiment, there may be an indication in the DCI indicating whether the PRACH will be sent using the RACH resources associated with the CORESET group using which the PDCCH command is sent (and / or selecting (multiple) SSBs of the CORESET group using which the PDCCH command is sent), or using the RACH resources associated with another CORESET group, or whether (at least) two PRACHs will be sent using the RACH resources associated with two CORESET groups.

[0091] In one embodiment, if the terminal device is configured with a time alignment timer for each TRP (or CORESETPoolIndex or PCI) and the timer expires, the terminal device can trigger a random access process by using a RACH resource corresponding to or associated with the TRP (or CORESETPoolIndex or PCI) for which the timer has expired (and / or selecting (multiple) SSBs corresponding to or associated with the TRP (or CORESETPoolIndex or PCI) for which the timer has expired).

[0092] The above proposed solution enables determination of two TAs for uplink multi-TRP operation and enables one TRP to trigger a RACH process or PRACH transmission to the same TRP or another TRP or even to two TRPs for PDCCH command purposes. The proposed solution reduces downlink overhead due to a single PDCCH command under multiple TRPs.

[0093] Figure 5 An embodiment is shown. The figure shows a simplified example of an apparatus to which an embodiment of the present invention is applied. In some embodiments, the apparatus may be a terminal device, a user equipment or a part of a terminal device or a user equipment.

[0094] It should be understood that the device is described herein as an example to illustrate some embodiments. It will be apparent to those skilled in the art that the device may also include other functions and / or structures, and not all described functions and structures are required. Although the device is described as one entity, different modules and memories may be implemented in one or more physical or logical entities.

[0095] The example apparatus 204 may include a control circuit 500 configured to control at least a portion of the operation of the apparatus.

[0096] The apparatus may comprise a memory 502 for storing data. Furthermore, the memory may store software 504 executable by the control circuit 500. The memory may be integrated in the control circuit.

[0097] The apparatus includes one or more interface circuits 506, which may be operably connected to the control circuit 500. The interface circuit 506 may be a set of transceivers configured to communicate with a network entity such as a transmission reception point, a physical cell, a control resource set group, or a radio access network node such as an eNodeB or gNB of a wireless communication network. The interface circuit 506 may provide a wired or wireless connection. The apparatus may also include a user interface 508.

[0098] In one embodiment, the software 504 may include a computer program including program code means adapted to cause the control circuit 500 of the apparatus to implement at least some of the embodiments described above.

[0099] Fig. 6A An embodiment is shown. The figure shows a simplified example of an apparatus or network element to which an embodiment of the present invention is applied. In some embodiments, the apparatus may be a network entity, such as a transmission reception point, a physical cell, a control resource set group, or a radio access network node, such as an eNodeB or gNB of a wireless communication network.

[0100] It should be understood that the device is described herein as an example to illustrate some embodiments. It will be apparent to those skilled in the art that the device may also include other functions and / or structures, and not all described functions and structures are required. Although the device is described as one entity, different modules and memories may be implemented in one or more physical or logical entities.

[0101] The apparatus 200 of this example includes a control circuit 600 configured to control at least part of the operation of the apparatus.

[0102] The apparatus may comprise a memory 602 for storing data. Furthermore, the memory may store software 604 executable by the control circuit 600. The memory may be integrated in the control circuit.

[0103] The apparatus also includes one or more transceivers 606, 608, which are configured to connect the apparatus to other devices and network elements of the radio access network. The interface circuit 606 may be one or more transceivers configured to communicate with a terminal device or a user terminal. The interface circuit 608 may be one or more transceivers configured to communicate with other network elements such as a core network. The interface may provide a wired or wireless connection.

[0104] In one embodiment, the software 606 may comprise a computer program including program code means adapted to cause the control circuit 600 and the transceivers 606, 608 of the apparatus to implement at least some of the embodiments described above.

[0105] In an embodiment, Figure 6B As shown, Fig. 6A At least some of the functions of the apparatus may be shared between two physically separate devices, thereby forming an operational entity. Therefore, it can be seen that the apparatus depicts an operational entity including one or more physically separate devices for performing at least some of the processes described. Therefore, the use of such a shared architecture Figure 6B The apparatus may include a remote control unit RCU 610, such as a host computer or a server computer, which is operatively coupled (e.g., via a wireless or wired network) to a remote distributed unit RDU 612 located in a base station. In an embodiment, at least some of the described processes may be performed by the RCU 610. In an embodiment, the execution of at least some of the described processes may be shared between the RDU 612 and the RCU 610.

[0106] In an embodiment, the RCU 610 may generate a virtual network through which the RCU 610 communicates with the RDU 612. Typically, virtual networking may involve the process of combining hardware and software network resources and network functions into a single software-based management entity, a virtual network. Network virtualization may involve platform virtualization, which is typically combined with resource virtualization. Network virtualization may be classified as external virtual networking, which combines many networks or portions of networks into a server computer or host computer (e.g., to an RCU). External network virtualization is for optimized network sharing. Another category is internal virtual networking, which provides network-like functionality to software containers on a single system. Virtual networks may also be used to test terminal devices.

[0107] In an embodiment, the virtual network may provide a flexible allocation of operations between the RDU and the RCU. In practice, any digital signal processing task may be performed in either the RDU or the RCU, and the boundaries for transferring responsibilities between the RDU and the RCU may be selected based on the implementation.

[0108] There is no absolute chronological order for the steps and related functions described above and in the accompanying drawings, and some steps may be performed simultaneously or in a different order than a given step. Other functions may also be performed between steps or within steps. Some steps may also be omitted or replaced with corresponding steps.

[0109] The device or controller capable of performing the above steps can be implemented as an electronic digital computer, a processing system or a circuit that can include a working memory (random access memory RAM), a central processing unit (CPU) and a system clock. The CPU may include a set of registers, an arithmetic logic unit and a controller. The processing system, the controller or the circuit is controlled by a sequence of program instructions transmitted from the RAM to the CPU. The controller may contain a plurality of microinstructions for basic operations. The implementation of the microinstructions may vary according to the CPU design. The program instructions may be encoded by a programming language, which may be a high-level programming language, such as C, Java, etc., or a low-level programming language, such as a machine language or an assembler. The electronic digital computer may also have an operating system, which may provide system services to a computer program written with program instructions.

[0110] As used in this application, the term "circuitry" refers to all of the following: (a) hardware circuit implementations only, such as implementations in analog and / or digital circuits only, and (b) combinations of circuits and software (and / or firmware), such as (as applicable): (i) a combination of a processor or (ii) portions of a processor / software including a digital signal processor, software, and memory, which work together to enable the device to perform various functions; and (c) circuits, such as a microprocessor or a portion of a microprocessor, that require software or firmware for operation, even if the software or firmware is not physically present.

[0111] This definition of 'circuitry' applies to all uses of the term in this application. As another example, as used in this application, the term "circuitry" would also cover an implementation of merely a processor (or multiple processors) or portion of a processor and its (or their) accompanying software and / or firmware. The term "circuitry" would also cover, for example and if applicable to the particular element, a baseband integrated circuit or an application processor integrated circuit for a mobile phone, or a similar integrated circuit in a server, a cellular network device, or another network device.

[0112] An embodiment provides a computer program embodied on a distribution medium, comprising program instructions, which when loaded into an electronic device are configured to control the device to execute the above steps.

[0113] A computer program may be in source code form, object code form, or some intermediate form, and it may be stored in some carrier, which may be any entity or device capable of carrying the program. For example, such carriers include recording media, computer memories, read-only memories, and software distribution packages. Depending on the required processing power, a computer program may be executed in a single electronic digital computer, or it may be distributed among several computers.

[0114] The device can also be implemented as one or more integrated circuits, such as an application specific integrated circuit ASIC. Other hardware embodiments are also feasible, such as circuits constructed by separate logic components. Mixing of these different implementations is also feasible. When selecting an implementation method, those skilled in the art will consider, for example, the size and power consumption of the device, the necessary processing power, the production cost, and the set of requirements for production volume.

[0115] It is obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways.The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.

Claims

1. A method for a terminal device, comprising: receiving a random access indication message from a network entity, the random access indication message indicating whether transmission of at least one physical random access channel PRACH uses at least one random access resource corresponding to or associated with one or more network entities; Based on the random access indication message, the at least one PRACH is sent.

2. The method according to claim 1, further comprising: The random access indication message is received in downlink control information DCI.

3. The method according to claim 1 or 2, wherein the at least one PRACH transmitted uses one or more random access resources of the at least one random access resource.

4. The method according to claim 1 or 2, wherein the random access resource comprises at least one of the following: a random access preamble code index, a synchronization signal / physical broadcast channel SS / PBCH index, and a random access channel opportunity.

5. The method according to any of the preceding claims, wherein the random access indication message comprises at least one second random access resource, and the at least one second random access resource is used for contention-free random access corresponding to or associated with at least one network entity of the one or more network entities.

6. The method according to any of the preceding claims, wherein the random access indication message comprises an indication of the following random access resources: random access resources to be used for contention-based random access corresponding to or associated with at least one network entity of the one or more network entities.

7. The method according to any one of the preceding claims, wherein receiving from the network entity comprises at least one of: receiving from a transmission reception point, receiving from a physical cell, and receiving via a control resource set group.

8. The method according to claim 5, further comprising: Based on the indication carried in the message or based on the indication carried separately, the existence of the at least one second random access resource in the message is determined.

9. The method according to any one of the preceding claims 1 to 3, wherein sending the at least one PRACH uses one or more random access resources among the at least one random access resource corresponding to or associated with a network entity whose corresponding timer has expired.

10. A method for a network entity, comprising: Obtaining a random access indication message; A random access indication message is sent to a terminal device, wherein the random access indication message indicates whether transmission of at least one physical random access channel PRACH uses at least one random access resource corresponding to or associated with one or more network entities.

11. The method according to claim 10, further comprising: The random access indication message is sent in downlink control information DCI.

12. The method according to claim 10 or 11, wherein the random access resource comprises at least one of the following: a random access preamble code index, a synchronization signal / physical broadcast channel SS / PBCH index, and a random access channel opportunity.

13. The method according to any one of the preceding claims 10 to 12, wherein the random access indication message comprises at least one second random access resource, and the at least one second random access resource is used for contention-free random access corresponding to or associated with the one or more network entities.

14. The method according to any one of the preceding claims 10 to 13, wherein the random access indication message comprises an indication of the following random access resources: random access resources to be used for contention-based random access corresponding to or associated with at least one of the one or more network entities.

15. An apparatus in a terminal device, comprising: at least one transceiver, wherein the at least one transceiver is configured to: receiving a random access indication message from a network entity, the random access indication message indicating whether transmission of at least one physical random access channel PRACH uses at least one random access resource corresponding to or associated with one or more network entities, Based on the random access indication message, the at least one PRACH is sent.

16. The apparatus of claim 15, wherein the at least one transceiver is further configured to: The random access indication message is received in downlink control information DCI.

17. The apparatus according to claim 15 or 16, wherein the at least one transceiver is further configured to: The at least one PRACH is sent using one or more random access resources of the at least one random access resource.

18. The apparatus according to claim 15 or 16, wherein the random access resource comprises at least one of the following: a random access preamble code index, a synchronization signal / physical broadcast channel SS / PBCH index, and a random access channel opportunity.

19. The apparatus according to any one of the preceding claims 15 to 18, wherein the random access indication message comprises at least one second random access resource, and the at least one second random access resource is used for contention-free random access corresponding to or associated with the one or more network entities.

20. The apparatus of any preceding claim 15 to 19, wherein the random access indication message comprises an indication of random access resources to be used for contention-based random access corresponding to or associated with at least one of the one or more network entities.

21. A device in a network element, comprising: at least one processor; as well as at least one transceiver, wherein the at least one processor is configured to: Obtaining a random access indication message; The transceiver is configured as follows: A random access indication message is sent to a terminal device, where the random access indication message indicates whether transmission of at least one physical random access channel PRACH uses at least one random access resource corresponding to or associated with one or more network entities.

22. The apparatus of claim 21 , wherein the at least one transceiver is further configured to: The random access indication message is sent in downlink control information DCI.

23. A computer program comprising instructions for causing an apparatus to at least: receiving a random access indication message from a network entity, the random access indication message indicating whether transmission of at least one physical random access channel PRACH uses at least one random access resource corresponding to or associated with one or more network entities, Based on the random access indication message, the at least one PRACH is sent.

24. A computer program comprising instructions for causing an apparatus to at least: Obtaining a random access indication message; The random access indication message is sent to the terminal device, where the random access indication message indicates whether the transmission of at least one physical random access channel PRACH uses at least one random access resource corresponding to or associated with one or more network entities.

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