CN111108783A

CN111108783A - Management of time advance values

Info

Publication number: CN111108783A
Application number: CN201780095070.1A
Authority: CN
Inventors: 彼得里·克拉; 马里奥·科斯塔
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2017-11-03
Filing date: 2017-11-03
Publication date: 2020-05-05
Anticipated expiration: 2037-11-03
Also published as: CN111108783B; WO2019086125A1

Abstract

A method for managing time advance values for a plurality of beams in wireless communications is provided. According to a first aspect, a client device transmits a time advance establishment request (TA ER) using a first beam associated with a first time advance value to establish a second TA value associated with a second beam. Since the beam associated with the valid TA value is used, signaling overhead and time delay can be reduced compared to the random access procedure. A network apparatus, method, and computer program are described.

Description

Management of time advance values

Technical Field

The present application relates to the field of wireless communications, and more particularly to managing time advance values for beams in wireless communications for client devices and network devices. Furthermore, the invention relates to a corresponding method and computer program.

Background

Since radio waves propagate over the air at a limited speed of light, there is a time delay between sending a message from a client device (e.g., a mobile phone) and receiving the message in a network device (e.g., a 5G base station). Naturally, the longer the path the radio wave travels, the greater the delay. To avoid interference, the client device should take this delay into account in the timing of its Uplink (UL) transmissions. The client device may achieve this by applying a compensation called Timing Advance (TA). However, before the client device can use the TA and establish a connection, the client device should obtain the correct TA value.

The client device may even connect to the network device using multiple beam pairs, where the beam pairs may include Tx beams in the client device and Rx beams at the network device, and vice versa. In this case, signals from different beam pairs may propagate between the client device and the network device through different physical paths due to, for example, scattering from surrounding objects. Thus, the TA values for different beam pairs may be different. Furthermore, if, for example, the client device moves, two beam pairs having the same TA value at one time may have different TA values at a later time.

Disclosure of Invention

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter.

It is an object to provide a method for managing time advance values of beams in wireless communication. This object is achieved by the features of the independent claims. Other embodiments are provided in the dependent claims, the description and the drawings.

According to a first aspect, a client device transmits a time advance establishment request (TA ER) using a first beam associated with a first Time Advance (TA) value to establish a second TA value associated with a second beam. Since beams with valid TA values can be used, signaling overhead and time delay can be reduced, e.g., compared to random access procedures.

In another embodiment of the first aspect, the client device is further configured to: receiving a TA establishment response, wherein the TA establishment response includes a TA procedure Identification (ID) and an indication of a corresponding allocated preamble; transmitting the allocated preamble using the second beam; receiving a TA command, where the TA command includes the TA procedure identifier and the second TA value; and assigning the second TA value to a TA procedure corresponding to the TA procedure ID. This may avoid contention on the random access channel. Thus, signaling overhead and latency may be reduced.

In another embodiment of the first aspect, the TA ER comprises an ID of the second beam, which may enable efficient acquisition of a new TA value. Thus, signaling overhead and latency may be reduced.

In another embodiment of the first aspect, the TA ER includes an ID of a TA procedure associated with the second beam, which may enable efficient acquisition of a valid TA value for a previously used TA procedure. Thus, signaling overhead and latency may be reduced.

In another embodiment of the first aspect, the client device is further configured to associate one or more TA procedures with one or more beams, wherein the TA value for each beam is determined by the associated TA procedure such that one beam is associated with only one TA procedure. Thus, the TA values for multiple beams may be maintained with a single process. Thus, signaling overhead and latency may be reduced.

In another implementation of the first aspect, the client device is further configured to: receiving a TA association change command, wherein the TA association change command comprises a beam ID and a TA process ID; and re-associating the beam corresponding to the beam ID to the TA procedure corresponding to the TA procedure ID. In this way, the association between the TA procedure and the beam can be changed dynamically. Thus, signaling overhead and latency may be reduced.

In another embodiment of the first aspect, the client device is further configured to send a TA setup request when the suspended beam is activated, which allows for efficiently acquiring a new TA value. Thus, signaling overhead and latency may be reduced.

In another embodiment of the first aspect, the client device is further configured to send the TA setup request when a time alignment timer expires or certain TA procedures have no TA value. Thus, the TA value may be maintained for multiple TA procedures. These TA values may be acquired later, even if they have expired or lack them. Thus, signaling overhead and latency may be reduced.

In another embodiment of the first aspect, the client is further configured to reset a time alignment timer associated with a particular TA procedure after assigning the TA value to the TA procedure, which allows the TA value to be updated upon expiration of the timer. The timer may be maintained as appropriate. Thus, signaling overhead and latency may be reduced.

In another embodiment of the first aspect, when recovering TA for a beam with an invalid TA value, the beam associated with the valid TA value may be used for communication. Therefore, communication can be maintained at all times. Thus, signaling overhead and latency may be reduced.

In another embodiment of the first aspect, the client device is further configured to acquire the TA value of the single beam via a random access procedure if all time alignment timers have expired. This allows a single TA value to be obtained. Thereafter, additional TA values may be efficiently acquired for other beams without a contention-based random access procedure. Thus, signaling overhead and latency may be reduced.

According to a second aspect, a network device is configured to transmit a Time Advance (TA) association change command to a client device, wherein the TA association change command includes a beam Identification (ID), a TA procedure ID, and an instruction to associate a beam corresponding to the beam ID to a TA procedure corresponding to the TA procedure ID. Thus, the association between the TA procedure and the beam may be changed when the network apparatus detects that it may be reasonable or desirable to change the association between the TA procedure and the beam. Therefore, the TA values of the plurality of beams can be effectively maintained.

In another embodiment of the second aspect, the network device is further configured to: receiving a TA establishment request; assigning a preamble to a TA procedure ID; transmitting a TA setup response, wherein the TA setup response includes the TA procedure ID and an indication of the preamble assigned to the TA procedure ID; receiving the allocated preamble; measuring a TA value of a TA procedure corresponding to the TA procedure ID based on the received allocated preamble; and transmitting a TA command, wherein the TA command includes the TA value and the TA procedure ID. Accordingly, since a preamble can be allocated to each TA procedure, additional TAs can be effectively measured. Therefore, the TA values of the plurality of beams can be effectively maintained.

According to a third aspect, a method comprises: a time advance establishment request (TA ER) is transmitted using a first beam associated with a first Time Advance (TA) value to establish a second TA value associated with a second beam. Since beams with valid TA values can be used, signaling overhead and time delay can be reduced, e.g., compared to random access procedures.

According to a fourth aspect, a method comprises: transmitting a Time Advance (TA) association change command to a client device, wherein the TA association change command includes a beam Identification (ID), a TA procedure ID, and an instruction to associate a beam corresponding to the beam ID to a TA procedure corresponding to the TA procedure ID. Thus, the association between the TA procedure and the beam may be changed when the network apparatus detects that it may be reasonable or desirable to change the association between the TA procedure and the beam. Therefore, the TA values of the plurality of beams can be effectively maintained.

According to a fifth aspect, there is provided a computer program comprising program code for performing the method according to the third or fourth aspect when the computer program is executed on a computer.

Many of the attendant features will be more readily appreciated as the same becomes better understood by reference to the following detailed description considered in connection with the accompanying drawings.

Drawings

The specification will be better understood from a reading of the following detailed description in light of the accompanying drawings, in which:

fig. 1 shows a schematic representation of a block diagram of a client device for sending a time advance request according to an example;

fig. 2 shows a schematic representation of a block diagram of a network apparatus for sending a time advance association change command according to an example;

fig. 3 shows a schematic representation of a communication with a propagation delay difference between a client device and a network device according to an example;

fig. 4 shows a schematic representation of an association of a time advance and a beam within a client device according to an example;

figure 5 shows a schematic representation of a signalling diagram of a time advance establishment procedure according to an example;

fig. 6 shows a schematic representation of a time advance establishment request between a client device and a network device according to an example;

FIG. 7 shows a schematic representation of a flow chart of a time advance establishment procedure according to an example;

figure 8 shows a schematic representation of a signalling diagram of a time advance association change procedure according to an example;

fig. 9 shows a schematic representation of a time advance association change command between a network device and a client device according to an example; and

fig. 10 shows a schematic representation of a flow chart of a time advance association change procedure according to an example.

In the drawings, like reference numerals are used to designate like components.

Detailed Description

The following description, given by way of example in connection with the accompanying drawings, is not intended to represent the only forms in which the present embodiments may be constructed or utilized. However, the same or equivalent functions and structures may be accomplished by different examples.

According to an example, a client device may use multiple beams to communicate with a network device. In most cases, for each Tx beam in the client device, there should be a corresponding Rx beam in the network device, and vice versa. The Tx beam and the Rx beam may constitute a beam pair. Since different beam pairs may have different Time Advance (TA) values due to, for example, different propagation paths, the client device associates each of its beams with one TA procedure, and the TA procedure determines the TA value of the associated beam. Each TA procedure may be associated with multiple beams, while each beam may be associated with only a single TA procedure, as a single beam may only have a single TA value. In addition, each beam and TA procedure may be assigned an Identification (ID). In addition, each TA procedure may be assigned a time alignment timer to ensure that each TA value is updated at least once within a set time interval.

If no beams have a valid TA value, and therefore no connection, the client device may use a random access procedure to acquire the TA value of a single beam. On the other hand, if at least one beam has a TA value, the client device may use that beam to request a new TA value for the other beams. According to one example, the client device initiates the procedure by sending a TA setup request using the beam of the connection. If the client device requests a TA value for a previously unconnected beam, the setup request includes the ID of the beam requesting the TA value. If the beam has been previously connected but the associated TA value has become invalid, the setup request includes the ID of the associated TA procedure.

Since multiple beams may be associated with a single TA procedure, the client device need not separately request a TA value for each beam through a contention-based random access procedure. This can significantly reduce signaling overhead and latency. A single setup request may also be used to request TA values for multiple TA procedures or multiple beams. In this case, the request includes multiple IDs, which may reduce signaling overhead even further.

According to an example, the network device may respond to the TA setup request by transmitting a TA setup response including a TA procedure ID and an indication of a preamble assigned to each TA procedure. The client device then transmits a corresponding preamble using the beam associated with each TA procedure. When the network device receives the preambles, the network device may measure the propagation delay of each preamble to determine the correct TA value for each TA procedure. In this way, the network device can determine the TA value without contention on the random access channel. Finally, the network device sends a TA command, which includes a TA procedure ID and a corresponding TA value.

In the above process, the client device acquires the TA values of the other beams using the active connection between one beam pair having a valid TA value. Thus, the client device need not use the contention-based random access procedure described previously. This eliminates unnecessary signaling and delay inherent in contention-based random access procedures.

As described above, multiple beams may be associated with a single TA procedure. However, if the client device moves, for example, two beams that previously had the same TA value (within a reasonable accuracy) may not have the same TA value after the client device moves. Therefore, it would be advantageous if the client device could modify the association between the beam and the TA procedure.

According to one example, the change in association between the beam and the TA procedure is initiated by the network apparatus. The network device transmits a TA association change command that includes a beam ID, a TA procedure ID, and an instruction for the client device to associate the corresponding beam with the corresponding TA procedure. After the client device has changed the above-described association, the TA procedure is likely to have an invalid TA value. In this case, the client device may send a TA setup request to obtain a valid TA value using the previously described procedure. Alternatively, the network device may automatically send a TA setup response after the TA association command without the client device sending a TA setup request.

Fig. 1 and 2 schematically illustrate a client device 100, e.g. a wireless device, in a wireless communication system. Client device 100 includes a processor 101, a receiver 102, and a transmitter 103. As described in the examples, the client device 100 may be used to perform functions and operations related to the client device 100. The wireless communication system further includes a network device 200, such as a Transmission and Reception Point (TRP) or a 5G base station (gNB), where the network device 200 may also include a processor 201, a receiver 202, and a transmitter 203. As described in the examples, network device 200 may also be used to perform functions and operations associated with network device 200.

The client device 100 may be any one of the following: user Equipment (UE) in Long Term Evolution (LTE), a Mobile Station (MS), a wireless terminal, or a mobile terminal capable of communicating wirelessly in a wireless communication system (sometimes also referred to as a cellular radio system). The client device 100 may also be referred to as a mobile phone, a cellular phone, a tablet, or a laptop computer with wireless capability. Client device 100 in this context may be, for example, a portable, pocket-storable, hand-held, computer-included, or vehicle-mounted mobile device capable of communicating voice or data with other entities (such as other receivers or servers) via a wireless access network. The client device 100 may be a Station (STA), which is any device that includes a Medium Access Control (MAC) compliant IEEE802.11 and a physical layer (PHY) interface to the Wireless Medium (WM).

The network device 200 may be a transmit-receive point (TRP) or a 5G base station (gNB). The network apparatus 200 may be a base station, a (radio) network node, or an access point, or a base station, such as a Radio Base Station (RBS), which in some networks may be referred to as a transmitter, "eNB", "eNodeB", "gNB", "gdnodeb", "NodeB", or "B node", depending on the technology and terminology used. The radio network nodes may have different classes, e.g. macro eNodeB, home eNodeB, or pico base station, based on the transmission power and the corresponding cell size. The wireless network node may be a Station (STA) which is any device comprising a Medium Access Control (MAC) compliant with IEEE802.11 and a physical layer (PHY) interface to the Wireless Medium (WM).

Fig. 3 schematically illustrates communication between a client device 100 and a network device 200 according to an example. The network device 200 and the client device 100 are connected using two beam pairs. The first beam comprises beam 303 and beam 304 and the second beam pair comprises beam 305 and beam 306. In these two pairs, one beam is a Tx beam and the other is an Rx beam. The propagation paths of the first and second beam pairs are shown by dashed

lines

307 and 308, respectively. As can be seen in fig. 3, the radio waves between the

first beam pair

303, 304 travel directly along path 307, while the radio waves between the

second beam pair

305, 306 travel along path 308 bypassing the building 309. Thus, the first path 307 is significantly shorter than the second path 308. Thus, the propagation time and TA value of the two beam pairs may be significantly different, and the beam pairs should be associated with different TA procedures to maintain different TA values.

Fig. 4 shows a schematic representation of an association within a client device 100 according to an example. The client device 100 includes three TA processes, TA process 1401, TA process 2402, and TA process 3403. The TA procedure 1401 includes a valid TA value 404 and is associated with three beams (beam 1407, beam 2408, and beam 3409). Thus, the TA values for the three beams are determined by the TA procedure 1401, and the current TA values for these beams are the TA values 404. TA procedure 2402 and TA procedure 3403 are associated with beam 4410 and beam 5411, respectively. Further, the TA procedure 2402 includes a valid TA value 405, so the beam 4410 may be used for data transmission. On the other hand, the TA procedure 3403 does not include a valid TA value as indicated by the null field 406. Thus, the associated beam 5411 cannot be used to form an uplink connection. Further, since each beam is associated with a TA procedure, each beam is also associated with a TA value as long as the associated TA procedure includes a valid TA value.

Since different beams are associated with different TA procedures, the TA values for these beams can be maintained independently. For example, the TA value of beam 4410 determined by TA process 2402 may be maintained independently of the TA values of the other beams. On the other hand, since beam 1407, beam 2408, and beam 3409 are all associated with TA procedure 1401, the TA values for these beams are always the same unless these associations are changed.

The initial creation of the TA procedure may be done by the client device 100 or by some external agent, such as the network device 200. Similarly, the initial association between the beam and the TA procedure and the subsequent change to the association may be done by the client device 100 or by some external agent.

In the above example, the client device includes a number of TA procedures and beams, and each TA procedure is associated with a number of beams. However, these numbers are merely examples. In general, the client device 100 may include any number of TA processes or beams, and each TA process may be associated with any number of beams. However, a single beam can only be associated with a single TA procedure, since the procedure determines the TA value for that beam, and it would not be beneficial to have multiple TA values for a single beam.

Fig. 5 shows a schematic representation of a TA establishment procedure according to an example. At the beginning of the process, there is at least one beam with a valid TA value that has been established between the client device 100 and the network device 200. The purpose of the TA establishment procedure shown in fig. 5 is to obtain valid TA values for other beams.

The client device 100 begins the process for some reason 501. The reasons for this may be, for example, acquiring TA values for beams that are not used in the random access procedure, expiration of time alignment timers for some beams, or some TA values may be invalid after an association change, or new TA values may be required for activation of suspended beams. This may occur, for example, when an additional beam is required for an ongoing data transmission. In operation 503, the client device 100 transmits a TA setup request 502 to the network device 200 using a beam with a valid TA value. If the beams have been previously connected, the request 502 may include the ID of the beam or beams to be connected, or the ID of the associated TA procedure. An example of this operation is presented later in fig. 6.

Referring to fig. 5, the network device 200 assigns a preamble to each ID in the request 502 and sends a TA procedure ID and an indication of the respective preamble to the client device 100 in a TA setup response 504. After receiving the response 504, the client device 100 transmits each preamble using the beam associated with the respective TA procedure indicated by the response 504. If only a single TA value is requested, one preamble 505 is transmitted. On the other hand, if n TA values are requested, the client device 100 transmits all the corresponding n preambles 508 as indicated by

arrows

505, 506, and 507. Further, if a plurality of beams are associated with one TA procedure, the corresponding preamble is transmitted using all beams.

After receiving the one or more preambles 508, the network apparatus 200 can determine the propagation delay of each TA procedure, and thus the TA value, because each preamble is linked to a single TA procedure. This avoids contention on the random access channel and procedure. The network device 200 then sends the TA value and corresponding TA procedure ID to the client device 100 in a TA command 509 on the shared channel. Alternatively, the TA value and TA procedure ID may be sent in a random access response. In operation 510, the client device 100 applies the TA value to the corresponding TA procedure. Further, the client device 100 may restart a time alignment timer associated with the TA procedure that acquired the TA value.

Fig. 6 shows a schematic representation of a TA set-up request according to an example. Client device 100 includes two TA processes, TA process 1601 and TA process 2602. TA process 1601 is associated with beam 1605 as indicated by arrow 612, while TA process 2602 is associated with beam 2606 as indicated by arrow 613. Beam 1605 corresponds to physical beam 607 and the associated TA procedure 1601 includes a valid TA value 603. Further, beam 607 in client device 100 and beam 608 in network device 200 constitute a beam pair. Thus, there may be an active uplink connection between beam 607 and beam 608. On the other hand, the TA procedure 2602 does not include a valid TA value as indicated by the null field 604. Thus, there is no active connection for the associated beam 2606. Fig. 6 does not show the corresponding physical beams.

To obtain a valid TA value for beam 2606, client device 100 sends TA setup request 502 to network device 200 using connected beam 1605. The direction of the request is indicated by arrow 610, e.g., from client 100 to network device 200. The request 502 includes an Identification (ID) 609. ID 609 is the ID of beam 2606 if beam 2606 was not previously connected. On the other hand, if beam 2606 has been previously used, but the associated TA value has become invalid, ID 609 is the ID of TA procedure 2602. Since the already connected beam is used to request the TA value of the second beam, a contention-based random access procedure is not required. This may reduce signaling overhead and latency.

Although in the above example each TA procedure is associated with only a single beam, this is not generally the case. Each TA procedure may be associated with multiple beams, while one beam may be associated with only one TA procedure. Furthermore, a single TA establishment request may be used to request TA values for multiple TA procedures, which reduces the amount of signaling since separate requests for each beam are not required.

Fig. 7 shows a schematic representation of a TA establishment procedure according to an example. This may be an example of the process presented in the example of fig. 5. When the above process starts, the client device 100 includes a TA process 701 and a beam 702 (as indicated by the arrow between the TA process 701 and the beam 702) associated with the TA process 701. The client device sends a TA setup request 502 to the network device 200 to obtain a valid TA value for the TA procedure 701 and, thus, for the beam 702. Naturally, the request 502 is sent using a certain beam with a valid TA value (this beam is not shown in fig. 7). The network apparatus 200 assigns the preamble 704 to the TA procedure ID703 corresponding to the TA procedure 701, and sends back an indication of the TA procedure ID703 and the preamble 704 in the TA establishment response 504. After receiving the response 504, the client device 100 transmits a preamble 704 to the network device 200 using the beam 702, as indicated by arrow 505. Based on the preamble, the network device 200 determines a TA value 705 and transmits the TA value 705 to the client device 100 in a TA command 509 together with the TA procedure ID 703. After receiving the command 509, the client device 100 applies a TA value 705 to the TA procedure 701. Thus, the TA procedure 701 now includes a valid TA value and the associated beam 702 may be used for uplink transmission.

Fig. 8 shows a schematic representation of a TA association change procedure according to an example. The network device 200 initiates the process at operation 801. This may occur, for example, because the TA value becomes invalid for some subset of beams associated with the same TA procedure. This may occur, for example, when the client device 100 is physically moving. This movement may cause the radio waves of some beams to propagate differently, which changes the correct TA value. Thus, it may no longer be valid for two beams that previously used the same TA value to use the same TA value, and one of the beams should be associated with another TA procedure.

The network device 200 transmits a TA association change command 802 to the client device 100. The command 802 includes a TA procedure ID, a beam ID, and an instruction to associate a TA procedure corresponding to the TA procedure ID to a beam corresponding to the beam ID.

In operation 803, after receiving the command 802, the client device 100 changes the association as indicated by the command 802. Since one beam may be associated with only one TA procedure, when a beam is associated with a TA procedure corresponding to a TA procedure ID, any previous association of the beam corresponding to the beam ID is removed. Some TA procedures may not have a valid TA value after the association has changed. This may occur, for example, when the TA association command 802 has indicated that the beam is associated with a TA procedure that has not been previously used (and therefore does not include a valid TA value). In this case, in step 804, the client device 100 may send a TA setup request 502 to the network device, initiating a TA setup procedure as shown in the example of fig. 5. On the other hand, the network device 200 may automatically send a TA setup response 504 after sending the TA association change command 802, since a new TA value may be needed after the association is changed. Thus, the remainder of step 805 is initiated without the need for the client device 100 to send the request 502.

Fig. 9 shows a schematic representation of a TA association change command according to an example. The network device 200 sends an association change command 802 to the client device 100 using the

beam pair

904, 905. The direction of the command is indicated by arrow 906 from the network device 200 to the client device 100. The command 802 includes a TA procedure ID 902, a beam ID 903, and instructions 901 for the client device 100 to associate a TA procedure corresponding to the TA procedure ID 902 to a beam corresponding to the beam ID 903.

Fig. 10 shows a schematic representation of a TA association change procedure according to an example. This may be an example of the process presented in fig. 8. Before the process begins, the client device includes a TA process 11001, and two beams associated with the TA process 11001: beam 11002 and beam 21003. At the start of this process, the network device 200 transmits a TA association change command 802 to the client device 100. Command 802 indicates association of beam 21003 with a new TA procedure 21004. When client device 100 associates beam 21003 with TA process 21004, the association between beam 21003 and TA process 11001 is removed as indicated by the dashed arrow because a beam can only be associated with one TA process.

After the association is changed, client device 100 may send TA setup request 502 to network device 200 because TA procedure 21004 does not include a valid TA value. Request 502 includes ID 1005 of TA procedure 21004. Upon receiving the request 502, the network device 200 assigns a preamble 1006 to the ID 1005 and transmits a TA setup response 504 containing the ID 1005 and an indication of the assigned preamble 1006. After receiving the response 504, the client device 100 transmits the preamble 1006 using the beam 21003. When the network device 200 receives the preamble 1006, the network device 200 may determine the TA value 1007 of the TA procedure 21004 and send the TA value 1007 in the TA command 509 back to the client device 100 together with the TA procedure ID 1005. After receiving command 509, client device 100 may apply TA value 1007 to TA process 21004.

The functions described herein may be performed, at least in part, by one or more computer program product components, such as software components. According to an example, the network apparatus 200 and/or the client apparatus 100 comprise a

processor

101, 201 configured by program code which, when executed, performs examples of the operations and functions described. Alternatively or additionally, the functions described herein may be performed, at least in part, by one or more hardware logic components. For example, but not limited to, illustrative types of hardware logic components that may be used include field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), system-on-a-chips (SOCs), Complex Programmable Logic Devices (CPLDs), Graphics Processing Units (GPUs).

Any range or device value given herein may be extended or altered without losing the effect sought. Also, any example may be combined with other examples unless explicitly prohibited.

Although the subject matter has been described in language specific to structural features and/or acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as examples of implementing the claims, and other equivalent features and acts are intended to fall within the scope of the claims.

It should be appreciated that the benefits and advantages described above may relate to one example or may relate to several examples. The embodiments are not limited to those embodiments that solve any or all of the above problems or those embodiments that have any or all of the benefits and advantages. It will also be understood that reference to "an" item may refer to one or more of those items. The term "and/or" may be used to indicate that one or more of its connected may occur. Two or more associations may occur, or only one of the associations may occur.

The steps of the methods described herein may be performed in any suitable order, or simultaneously where appropriate. In addition, individual blocks may be deleted from any of the methods without departing from the spirit and scope of the subject matter described herein. Aspects of any of the examples described above may be combined with aspects of any of the other examples described to form further examples without losing the effect sought.

The term "comprising" is used herein to mean including the identified method, block, or element, but that such block or element does not include the exclusive list, and that the method or apparatus may include other blocks or elements.

The term "beam" may be used herein to refer to a Tx or Rx beam, a Tx/Rx beam pair, a Tx or Rx port, or a Tx/Rx port pair, or any other component or pair of components used to transmit and/or receive signals in a wireless communication system.

It is to be understood that the above description is by way of example only and that various modifications may be made by those skilled in the art. The above specification, examples, and data provide a complete description of the structure and use of exemplary embodiments. Although various examples have been described above with a certain degree of particularity, or with reference to one or more individual examples, those skilled in the art could make numerous alterations to the disclosed examples without departing from the spirit or scope of this specification.

Claims

1. A client device (100) for:

a time advance establishment request TA ER (502) is transmitted using a first beam (605) associated with a first time advance TA value (404, 405, 603) to establish a second TA value (406, 604, 705) to be associated with a second beam (606).

2. The client device of claim 1, further to:

receiving a TA setup response (504), wherein the TA setup response comprises an indication of a TA procedure identity ID (703) and a corresponding allocated preamble (704);

transmitting the allocated preamble using the second beam;

receiving a TA command (509), wherein the TA command includes the TA procedure ID (703) and the second TA value (705); and

assigning the second TA value to a TA procedure corresponding to the TA procedure ID.

3. The client device according to any of the preceding claims, wherein the TA ER comprises an ID of the second beam.

4. The client device according to any of preceding claims 1-2, wherein the TAER comprises an ID of a TA procedure associated with the second beam.

5. The client device of any of the preceding claims, further to

Associating one or more TA procedures (407- > 411) with one or more beams (401, 402, 403, 605, 606), wherein the TA value (404, 405) for each beam is determined by the associated TA procedure such that one beam is associated with only one TA procedure.

6. The client device of any of the preceding claims, further to:

receiving a TA association change command (802), wherein the TA association change command comprises a beam ID (903) and a TA procedure ID (902);

re-associating the beam corresponding to the beam ID to the TA procedure corresponding to the TA procedure ID.

7. The client device of any of the preceding claims, further to

Transmitting the TA establishment request when a suspended beam is activated.

8. The client device of any of the preceding claims, further to

The TA setup request is sent when a time alignment timer expires or certain TA procedures have no TA value.

9. The client device of any of the preceding claims, further to

Resetting a time alignment timer associated with a particular TA procedure after assigning the TA value to the particular TA procedure.

10. The client device of any preceding claim, wherein the beam associated with a valid TA value is available for communication when TA is restored for a beam with an invalid TA value.

11. The client device of any of the preceding claims, further to

Acquiring the TA value of a single beam via a random access procedure if all time alignment timers have expired.

12. A network device (200) for:

transmitting a time advance, TA, association change command (802) to a client device (100), wherein the TA association change command comprises a beam identification, ID, (903), a TA procedure ID (902, 1004), and an instruction (901), the instruction (901) to associate a beam corresponding to the beam ID to a TA procedure corresponding to the TA procedure ID.

13. The network device of claim 12, further configured to:

receiving a TA setup request (502);

assigning a preamble (704) to the TA procedure ID (703, 1005);

transmitting a TA setup response (504), wherein the TA setup response includes the TA procedure ID and an indication of the preamble assigned to the TA procedure ID;

receiving the allocated preamble;

measuring a TA value of a TA procedure corresponding to the TA procedure ID based on the received allocated preamble (705, 1007); and

transmitting a TA command (509), wherein the TA command includes the TA value and the TA procedure ID.

14. A method, comprising:

a time advance establishment request, TAER, is transmitted (503) using the first beam associated with the first time advance, TA, value to establish a second TA value associated with the second beam.

15. A method, comprising:

transmitting (906) a time advance, TA, association change command to a client device, wherein the TA association change command includes a beam identification, ID, a TA procedure ID, and an instruction to associate a beam corresponding to the beam ID to a TA procedure corresponding to the TA procedure ID.

16. A computer program comprising program code for performing the method according to claim 14 or claim 15 when the computer program is executed on a computer.