Beam discovery procedure performed by user equipment

Abstract

A mechanism is provided for performing a beam discovery procedure for a serving access network node. The method is performed by a user equipment. The method includes receiving at least two SSBs as part of performing the beam discovery procedure. Each of the at least two SSBs includes a PSS and an SSS. In each of the SSBs, the PSS includes a PSS sequence and the SSS includes an SSS sequence. All the SSBs have the same PSS sequence but different SSS sequences from each other. The method includes including symbols for which the PSS of the SSB was received from the serving access network node in the set of evaluation symbols when a received power of at least one of the SSS of the SSB received from the serving access network node and the SSS of any SSB not received from the serving access network node satisfies a power-related criterion.

Description

Technical Field

[0001] The embodiments presented in this specification relate to a method, user equipment, computer program, and computer program product for performing a beam discovery procedure for a serving access network node.

Background Art

[0002] In a communication network, there may be challenges in obtaining good performance and capacity for a given communication protocol, its parameters, and the physical environment in which the communication network is deployed.

[0003] For example, in next-generation mobile communication networks, frequency bands of many different carrier frequencies may be required. For example, such low frequency bands may be required to achieve sufficient network coverage for wireless devices, and higher frequency bands (e.g., millimeter wavelengths (mmW), i.e., around 30 GHz and above 30 GHz) may be required to reach the required network capacity. Generally speaking, at high frequencies, the propagation characteristics of the wireless channel are more challenging, and beamforming may be required in both the network nodes and wireless devices of the network to reach a sufficient link budget.

[0004] To compensate for the expected high propagation loss, narrow-beam transmit / receive schemes may be required at such high frequencies. For a given communication link, each beam can be applied at both the network end (represented by the network node or its transmit / receive point TRP) and the terminal end (represented by the user equipment), which is typically called a beam pair link (BPL). One task of beam management procedures is to discover and maintain beam pair links. BPLs (i.e., both the beam used by the network node and the beam used by the user equipment) are expected to be discovered and monitored by the network using measurements of downlink reference signals, such as channel state information reference signals (CSI-RS) or synchronization signal block (SSB) signals, which are used for beam management.

[0005] CSI-RS for beam management can be transmitted periodically, semi-permanently, or aperiodically (event-triggered), and these signals may be shared among multiple user devices or device-specific. SSB is transmitted periodically and shared for all user devices. To help user devices discover suitable network node beams, the network node transmits a reference signal on different transmit (TX) beams during the P-1 subprocedure, allowing the user devices to perform measurements such as reference signal received power (RSRP), and returns a report of N best TX beams (where N may be set by the network). Furthermore, the transmission of the reference signal on a given TX beam can be repeated so that user devices can evaluate suitable receive (RX) beams. A reference signal shared among all user devices served by the TRP may be used to determine a first rough direction for the user devices. Using SSB as a reference signal may be suitable for such periodic TX beam sweeps in the TRP. One reason for this is that SSB is transmitted periodically anyway (for initial access / synchronization purposes), and SSB is also expected to be beamformed at higher frequencies to overcome the higher propagation losses mentioned above.

[0006] Next, in order to determine the more detailed orientation of each user device, a finer beam sweep may be performed at the network node during the P-2 subprocedure with a narrower beam than that used during the P-1 subprocedure. In this specification, CSI-RS may be used as the reference signal. With respect to the P-1 subprocedure, the user device performs measurements such as the reference signal received power (RSRP) and returns a report of the N best TX beams (where N may be set by the network).

[0007] Furthermore, the CSI-RS transmission on the selected transmit beam during the P-2 subprocedure can be repeated in the P-3 subprocedure so that the user equipment can evaluate the appropriate RX beam on its own equipment.

[0008] SSB is a broadcast signal whose primary purpose is to provide basic system information used for initial synchronization, initial access, and mobility measurements. Two exemplary structures of SSB100a and 100b are shown in Figure 1(a) and (b). SSB consists of Primary Synchronization Signals (PSS) 110, 110-1, 110-2, Secondary Synchronization Signals (SSS) 130, 130-1, 130-2, and Physical Broadcast Channels (PBCH) 120, 120-1, 120-2, 130, 140, 140-1, 140-2. In some examples, the PSS and SSS portions of the SSB are transmitted over 127 subcarriers, with subcarrier spacings of 15kHz or 30kHz below 6GHz and 120kHz or 240kHz above 6GHz.

[0009] In some types of wireless networks, three different PSS sequences can be used. These PSS sequences are derived from different cyclic shifts of an M sequence with a basic length of 127. User equipment knows when to transmit the SSS when it detects the PSS. In some types of wireless networks, there are 336 different SSS sequences derived from the shifts of two basic M sequences. The combination of PSS and SSS determines the physical cell identity (PCI) of the cell. The 336 different SSSs, along with the three different PSSs, give 1008 different PCIs.

[0010] At lower frequencies, each access network node within a cell is expected to transmit one SSB to cover the entire cell, while at higher frequencies, several beamformed SSBs are expected to be required to achieve coverage across the entire cell. For some types of wireless networks, the maximum number of SSBs per cell is as follows: 4 SSBs per cell below 3 GHz, 8 SSBs per cell between 3 and 6 GHz, and 64 SSBs per cell above 6 GHz. SSBs can be transmitted in SSB transmit bursts that can last up to 5 ms. The period of the SSB burst is configurable. In some examples, the period is 5, 10, 20, 40, 80, or 160 ms.

[0011] One alternative method for user equipment to select a received beam during the P-3 subprocedure is to have the user equipment evaluate different candidate received beams during a periodic SSB transmission, instead of measuring with respect to CSI-RS. One advantage of using SSB instead of CSI-RS is that the extra overhead of CSI-RS transmission is not required. As will be explained below, theoretically, if each SSB consists of four OFDM symbols as shown in Figure 1(a), up to four candidate received beams can be evaluated during each SSB burst transmission. The user equipment can then use one candidate received beam per OFDM symbol and measure the received power with respect to each candidate received beam. In this way, theoretically, up to four candidate received beams can be evaluated in a single SSB transmission. However, since the reception of PSS from a serving access network node may be mixed with PSS transmissions from other access network nodes using the same PSS sequence, the first symbol in the SSB, i.e., the symbol carrying the PSS, may not be useful for evaluating candidate received beams. This is because only three different PSS sequences are available, and therefore, it is likely that access network nodes in neighboring cells are using the same PSS sequence. If access network nodes in neighboring cells use the same PSS sequence, the user equipment will receive the same signal from multiple access network nodes, making the evaluation of candidate received beams unreliable. Therefore, in practice, it is often assumed that the user equipment cannot use the first OFDM symbol in the SSB to find a suitable received beam. Thus, according to the SSB in Figure 1(a), only three of the four OFDM symbols can be used during evaluation. The same is true for the SSB in Figure 1(b), where all symbols, including the PSS, are unavailable. This leads to longer latency in the P-3 subprocedure compared to when all symbols in the SSB are available.

[0012] Therefore, improved beam discovery procedures are needed, particularly procedures that allow user equipment to evaluate candidate received beams. [Overview of the project]

[0013] The object of the embodiments described herein is to provide efficient beam discovery that is not plagued by the above-mentioned problems, or at least has the above-mentioned problems reduced or mitigated.

[0014] According to a first aspect, a method for performing a beam discovery procedure relating to a serving access network node is provided. The method is performed by user equipment. During the beam discovery procedure, the user equipment evaluates a set of candidate beams based on measurements relating to a set of evaluation symbols, each having at least one evaluation symbol for each candidate beam. The method includes receiving at least two SSBs as part of performing the beam discovery procedure. Each SSB consists of symbols and is received from each access network node, one of which is the serving access network node. Each of the at least two SSBs includes a PSS and an SSS. In each SSB, the PSS includes a PSS sequence and the SSS includes an SSS sequence. All SSBs have the same PSS sequence but different SSS sequences from one another. The method includes including the symbols received from the serving access network node in a set of evaluation symbols in the PSS of an SSB when the received power of at least one of the SSS of the SSB received from the serving access network node and the SSS of any SSB not received from the serving access network node meets a power-related criterion.

[0015] According to a second embodiment, a user instrument is presented for performing a beam discovery procedure relating to a serving access network node. The user instrument is configured to evaluate a set of candidate beams based on measurements relating to a set of evaluation symbols, each having at least one evaluation symbol for each candidate beam, during the beam discovery procedure. The user instrument includes a processing circuit, which is configured to cause the user instrument to receive at least two SSBs as part of performing the beam discovery procedure. Each SSB consists of symbols and is received from each access network node, one of which is the serving access network node. Each of the at least two SSBs includes a PSS and an SSS. In each SSB, the PSS includes a PSS sequence and the SSS includes an SSS sequence. All SSBs have the same PSS sequence but different SSS sequences from one another. The processing circuit is configured to cause user equipment to include the symbol of the SSB's PSS received from the serving access network node in a set of evaluation symbols when at least one of the received powers of the SSB's SSS received from the serving access network node and the SSS of any SSB not received from the serving access network node meets the power-related criteria.

[0016] According to a third aspect, a user instrument is presented for performing a beam discovery procedure relating to a serving access network node. The user instrument is configured to evaluate a set of candidate beams based on measurements relating to a set of evaluation symbols, each having at least one evaluation symbol for each candidate beam, during the beam discovery procedure. The user instrument includes a receiving module configured to receive at least two SSBs as part of performing the beam discovery procedure. Each SSB consists of symbols and is received from each access network node, one of which is the serving access network node. Each of the at least two SSBs includes a PSS and an SSS. In each SSB, the PSS includes a PSS sequence and the SSS includes an SSS sequence. All SSBs have the same PSS sequence but different SSS sequences from one another. The user instrument includes an inclusion module configured to include the symbols received from the serving access network node in a set of evaluation symbols when the received power of at least one of the SSS of the SSB received from the serving access network node and the SSS of any SSB not received from the serving access network node meets a power-related criterion.

[0017] According to a fourth aspect, a computer program is presented for performing a beam discovery procedure relating to a serving access network node, which, when executed on user equipment, includes computer program code that causes user equipment to perform the method according to the first aspect.

[0018] According to the fifth aspect, a computer program product is presented which includes a computer program according to the fourth aspect and a computer-readable storage medium in which the computer program is stored. The computer-readable storage medium may be a non-temporary computer-readable storage medium.

[0019] Advantageously, these aspects provide efficient beam discovery without being troubled by the above problems.

[0020] Advantageously, these aspects enable the user equipment to use all symbols of the SSB for beam discovery purposes.

[0021] Advantageously, these aspects can be used to reduce the latency of the P-3 subprocedure, and thus, since the user equipment can evaluate more candidate received beams for each SSB transmission, it results in faster beam discovery.

[0022] Other objectives, features, and advantages of the embodiments included in the present invention will become apparent from the following detailed disclosure, the appended dependent claims, and the drawings.

[0023] In general, all terms used in the claims should be construed according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "an / a / the element, apparatus, component, means, module, step, etc." should be construed broadly as referring to at least one instance of the element, apparatus, component, means, module, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein need not be performed in the exact order disclosed, unless explicitly stated otherwise.

[0024] Next, the concept of the present invention will be described by way of example with reference to the accompanying drawings.

Brief Description of the Drawings

[0025] [Figure 1] A diagram schematically showing an example of an SSB. [Figure 2] A schematic diagram showing a communication network according to an embodiment. [[ID=​​ [Figure 4] A diagram schematically showing an evaluation of candidate reception beams in a user equipment based on measurements related to SSB according to an embodiment. [Figure 5] A flowchart of a method according to an embodiment. [Figure 6] A schematic diagram showing functional units of a user equipment according to an embodiment. [Figure 7] A schematic diagram showing functional modules of a user equipment according to an embodiment. [Figure 8] A diagram showing an example of a computer program product including a computer-readable storage medium according to an embodiment.

Embodiments for Carrying Out the Invention

[0026] Next, the concept of the present invention will be more fully described below with reference to the accompanying drawings in which some embodiments of the concept of the present invention are shown. However, the concept of the present invention may be embodied in many different forms and should not be construed as limited to the embodiments described herein. Rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete and will fully convey the scope of the concept of the present invention to those skilled in the art. Throughout the description, like numbers refer to like elements. Any step or feature shown by a dashed line should be regarded as optional.

[0027] Figure 2 is a schematic diagram showing a communication network 200 to which embodiments presented herein can be applied. The communication network 200 is a third-generation (3G) communication network, a fourth-generation (4G) communication network, a fifth-generation (5G) communication network, a sixth-generation (6G) communication network, or any evolution thereof, and can support any 3GPP communication standard where applicable. Alternatively, the communication network 200 can be a non-cellular network and / or a non-3GPP network, such as an IEEE 802.11 communication network, or any other wireless IEEE-compliant communication network. The communication network 200 includes a (wireless) access network represented by cells 210a, 210b, 210c, to which network access is provided by respective access network nodes 220a, 220b, 220c. Each cell 210a, 210b, 210c shares the same PSS sequence, indicated as "PSS1" in the figure. Furthermore, each cell has its own SSS sequence, indicated in the figure as "SSS1", "SSS2", and "SSS3". User equipment 600 is assumed to be served by access network node 220a. Thus, access network node 220a is the serving access network node for user equipment 600. Examples of access network nodes 220a, 220b, and 220c are radio access network nodes, radio base stations, base transceiver stations, node B, evolved node B, gNB, access points, and radio access backhaul integrated transmission nodes. Examples of user equipment 600 are wireless devices, mobile stations, mobile phones, handsets, wireless local loop phones, smartphones, laptop computers, tablet computers, network-equipped sensors, network-equipped vehicles, and so-called Internet of Things devices. Access network nodes 220a, 220b, and 220c are operably connected to the core network, which in turn is operably connected to one or more service networks.Other components and related functions of the communication network 200 are omitted in order to avoid obscuring the concepts presented herein.

[0028] As mentioned above, improved beam discovery procedures are needed, particularly procedures that allow user equipment to evaluate candidate received beams.

[0029] In this regard, one advantage of user equipment using SSB transmission to evaluate candidate received beams is that SSB is continuously transmitted for other purposes, and as a result, there is no additional overhead associated with using SSB for evaluating candidate received beams. Furthermore, user equipment continuously measures SSB from access network nodes in multiple cells for mobility purposes.

[0030] However, as disclosed above, in densely deployed wireless networks, it can be difficult to use all OFDM symbols in the SSB to evaluate candidate received beams in user equipment because user equipment is likely to receive PSS with high received power from access network nodes in multiple cells using the same PSS sequence. However, in some network deployments, cell isolation is so high that for some user equipment, PSS from access network nodes other than the serving access network node is received at very low power.

[0031] For user equipment positioned such that signals received from access network nodes other than the serving access network node are weak, reliable measurement of the received power of the PSS transmitted from the serving access network node is possible. For example, if each access network node has three sectors, the access network node can use one PSS sequence per sector, i.e., a total of three different PSS sequences. Then, since there are no PSSs transmitted from the same access network node using the same PSS sequence, and the PSS received from access network nodes in other cells is weak, the user equipment can measure the PSS without any significant interference. However, at the cell edge, strong interference from PSSs transmitted from neighboring network nodes may exist. This is just one example. In this case, the user equipment can actually use all symbols of the SSB to evaluate the candidate received beam.

[0032] Accordingly, embodiments disclosed herein relate to a mechanism for performing a beam discovery procedure relating to a serving access network node 220a. To obtain such a mechanism, a user device 600, a method performed by the user device 600, and a computer program product, for example, code in the form of a computer program, which causes the user device 600 to perform the method when executed on the user device 600, are provided.

[0033] Figure 3 is a flowchart illustrating an embodiment of a method for performing a beam discovery procedure for a serving access network node 220a. This method is performed by a user device 600. During the beam discovery procedure, the user device 600 evaluates a set of candidate beams based on measurements relating to a set of evaluation symbols, each having at least one evaluation symbol. This method is advantageously provided as a computer program 820.

[0034] In short, based on measurements of SSB received from both the serving access network node and access network nodes in neighboring cells, the user equipment determines whether it can use symbols that hold the PSS to evaluate candidate received beams.

[0035] User device 600 receives SSB from (at least) two different access network nodes 220a, 220b, and 220c, as in S104.

[0036] S104: As part of performing the beam discovery procedure, user equipment 600 receives at least two SSBs 100a and 100b. Each SSB 100a and 100b consists of symbols and is received from the respective access network nodes 220a, 220b, and 220c. One of the access network nodes 220a, 220b, and 220c is the serving access network node 220a.

[0037] The PSS sequence is the same in the received SSB. More specifically, each of at least two SSBs 100a and 100b includes PSSs 110, 110-1, and 110-2, and SSSs 130, 130-1, and 130-2. In each of SSBs 100a and 100b, PSSs 110, 110-1, and 110-2 include the PSS sequence, and SSSs 130, 130-1, and 130-2 include the SSS sequence. All SSBs 100a and 100b have the same PSS sequence but different SSS sequences from one another.

[0038] User equipment 600, as in S106, determines whether or not to include the PSS (of the SSB received from serving access network node 220a) in a set of evaluation symbols used when evaluating candidate beams.

[0039] S106: User device 600 includes the symbols received from the serving access network node 220a in a set of evaluation symbols when at least one of the received powers of SSS130, 130-1, 130-2 of SSB100a, 100b received from the serving access network node 220a and SSS130, 130-1, 130-2 of any SSB100a, 100b not received from the serving access network node 220a satisfies the power-related criteria, PSS110, 110-1, 110-2 of SSB100a, 100b includes the symbols received from the serving access network node 220a in a set of evaluation symbols.

[0040] In some embodiments, the actual evaluation of a pair of candidate beams is performed for the next transmission of SSB100a,100b from the serving access network node 220a. That is, for transmission n of SSB100a,100b from the serving access network node 220a, if it is determined that PSS110,110-1,110-2 of SSB100a,100b contains symbols received from the serving access network node 220a in a pair of evaluation symbols, then the actual evaluation of a pair of evaluation symbols is performed for the SSS and PSSS in transmission n+1 of SSB100a,100b from the serving access network node 220a.

[0041] Therefore, the user instrument measures the received power of symbols holding SSS in SSBs received from access network nodes in other cells that use the same PSS sequence as the serving cell, in order to determine whether the PSS symbols can be used to evaluate candidate received beams. For this purpose, the user instrument considers the received power of SSS130, 130-1, 130-2 of SSB100a, 100b received from the serving access network node 220a (and possibly together with the PSS of the SSB received from the serving access network node 220a), and / or the received power of SSS130, 130-1, 130-2 of any SSB100a, 100b not received from the serving access network node 220a.

[0042] In some cases, the user equipment compares the received power of the SSS received in an SSB from an access network node in another cell with the received power of the SSS received in an SSB from the serving access network node. If the received power of the SSS received in an SSB from an access network node in another cell is significantly lower than the received power of the SSS received in an SSB from the serving access network node, it can also be inferred that the received power of the PSS received in an SSB from these access network nodes in other cells is significantly lower than the received power of the PSS received in an SSB from the serving access network node. Thus, interference to the PSS is low, and reliable measurements of the PSS for evaluating candidate received beams are possible. The user equipment can then decide to include all symbols of the SSB transmission when evaluating candidate received beams, and thus beam discovery latency is reduced accordingly.

[0043] Next, embodiments relating to further details of performing a beam discovery procedure on the serving access network node 220a, which is performed by the user device 600, are disclosed.

[0044] A pair of candidate beams may be evaluated to determine which of the candidate beams the user device 600 should use for communication with the serving access network node 220a.

[0045] In some embodiments, the beam discovery procedure is triggered when the UE is moving in order to speed up the procedure for evaluating candidate received beams. Thus, in some embodiments, the user equipment 600 is configured to perform (optional) step S102.

[0046] S102: User device 600 receives an indication that user device 600 is moving at a velocity (and / or angular momentum) higher than the velocity threshold. In response to this (i.e., in response to user device 600 receiving that indication), the beam discovery procedure is triggered.

[0047] The following disclosure describes how a user device may estimate the level of interference caused by other access network nodes with respect to a symbol that holds a PSS.

[0048] In some embodiments, the user equipment measures the received power of the SSS in the SSB received from another access node having the same PSS sequence as the serving access network node, and compares this received power to the power of the SSS in the SSB received from the serving access network node. If the received power of the SSS in the SSB received from the other access node is low, the interference to the symbol holding the PSS is also considered low. Thus, the user equipment may determine that the power-related criteria are met and that the symbol holding the PSS can be used to evaluate the candidate received beam if the following equation holds: TIFF0007849473000001.tif15170

[0049] Here, P SSS,0 This is the received power of SSS130, 130-1, and 130-2 received from the serving access network node 220a, and P SSS,κ θ is the received power of the SSS received from access network nodes 220b and 220c κ that do not serve user equipment 600, where access network nodes 220b and 220c κ have the same PSS sequence as serving access network node 220a, and θ is the threshold power value. The threshold power value is a design parameter determined by or signaled to the user equipment.

[0050] In some embodiments, the user equipment considers only the received power of the SSS in the SSB received from other access nodes that have the same PSS sequence as the serving access network node. In particular, the user equipment may determine that the power-related criteria are met and that the symbols holding the PSS can be used to evaluate the candidate received beam if the following equation holds: TIFF0007849473000002.tif15170

[0051] In some embodiments, user equipment considers the received power of the SSS within the SSB received from a serving access network node and compares this received power to the received power of the PSS. One motivation for this is that, assuming no interference from other access nodes with the same PSS sequence, the received powers of the PSS and SSS should be the same if they are transmitted at the same power. In particular, user equipment may determine that the power-related criteria are met, and that a symbol holding the PSS can be used to evaluate a candidate received beam, if the following equation holds: TIFF0007849473000003.tif14170

[0052] Here, P PSS,0 This is the received power of PSS110, 110-1, and 110-2, and P SSS,0 θ is the received power of SSS130, 130-1, and 130-2 received from serving access network node 220a, and θ is the threshold power value.

[0053] As a general rule, when comparing two measurements performed using beams with different beamwidths, power may be adjusted to account for the difference in beamforming gain. Therefore, in some embodiments, SSBs 100a and 100b are received with beams having different beamforming gains, and compensation is made for the beamforming gain when determining whether power-related criteria are met. For example, user equipment uses a wide beam to receive SSS within an SSB from an access network node in another cell (having the same PSS sequence as the serving cell) and a narrow beam to receive SSS within an SSB from the serving access network node. This can represent a scenario when user equipment performs measurements on an SSB for mobility purposes. In some examples, user equipment compensates the measured received power of SSS within an SSB from an access network node in another cell according to the difference in beamforming gain between the narrow and wide beams.

[0054] In another example, the user equipment uses a narrow beam to receive both the SSS in the SSB from an access network node in another cell and the SSB from the serving access network node. In this case, the user equipment does not need to compensate for the measured received power of the SSS in the SSB from the access network node in another cell. In some examples, the user equipment uses the same narrow beam to receive both the SSS in the SSB from an access network node in another cell and the SSB from the serving access network node, sometimes also used to receive the PSS. Furthermore, if the user equipment measures with respect to the SSS in the SSB received from the serving access network node, the user equipment may use the same beam that is used to receive the PSS. In this case, there is no need to compensate for the measured received power of the SSS. Thus, in some embodiments, all SSBs 100a, 100b are received with a beam having equal beamforming gain.

[0055] An embodiment of the beam discovery procedure is disclosed below.

[0056] In some embodiments, during the beam discovery procedure, the user instrument 600 performs a beam sweep on a set of candidate beams, each of which receives one of the evaluation symbols and is used for measurement with respect to that evaluation symbol.

[0057] In some embodiments, candidate beams are selected that receive the highest received power for SSB 100a, 100b. In particular, in some embodiments, user equipment 600 is configured to perform (optional) step S108.

[0058] S108: User device 600 selects a candidate beam in which the evaluation symbol is received with the highest received power for communication with serving access network node 220a.

[0059] Figure 4 provides a schematic diagram of the inventive concept disclosed herein, along with a comparison with prior art. More specifically, Figure 4 shows the evaluation of a candidate received beam in a user instrument based on measurements relating to SSB.

[0060] For illustrative purposes, it is assumed that the user equipment is configured to generate eight beams and that SSBs are transmitted every 20 ms. Beam sweeping performed at the access network node is not shown, and this figure shows an SSB transmitted with a given beam from the access network node. According to the prior art, as shown in (a), the user equipment can evaluate three beams for each SSB transmission. Therefore, it takes three SSB transmissions, or 40 ms (+ duration of a single SSB transmission), for the user equipment to perform a complete beam sweep. According to the embodiments disclosed herein, as shown in (b), the user equipment can evaluate four beams for each SSB transmission, so that beam evaluation can be completed in two SSB transmissions, or 20 ms (+ duration of a single SSB transmission).

[0061] Next, refer to FIG. 5. FIG. 5 is a flowchart showing one specific embodiment for executing a beam discovery procedure regarding a serving access network node 220a executed by a user equipment 600 based on at least some of the embodiments, aspects, and examples disclosed above.

[0062] S201: The user equipment 600 sets a power threshold θ.

[0063] S202: The user equipment 600 measures the received power of the SSS within the SSB received from the serving access network node. The received power is assumed to be x dB.

[0064] S203: The user equipment 600 measures the received power of the SSS within the SSB received from another access network node within a cell having the same PSS sequence as the cell of the serving access network node. The maximum received power is assumed to be y dB.

[0065] S204: The user equipment 600 compares the received powers from S202 and S203. If y < x + θ, it proceeds to step 205. Otherwise, it proceeds to step 206.

[0066] S205: When evaluating a candidate received beam, the user equipment 600 uses all symbols of the SSB.

[0067] S206: When evaluating a candidate received beam, the user equipment 600 does not use the symbols within the SSB that hold the PSS.

[0068] The comparison of the received powers can be performed on either a linear scale or a logarithmic (dB) scale.

[0069] Various structures of SSBs are possible. In this regard, the embodiments disclosed herein are not limited to any particular structure of an SSB, as long as the characteristics disclosed above are satisfied. In some examples, each of the SSBs 100a, 100b comprises one or more symbols including PSS 110, 110-1, 110-2, one or more symbols including PBCH signals 120, 140, and one or more symbols including SSS 130, 130-1, 130-2 and a PBCH signal. One non-limiting example of such an SSB is provided in Figure 1(a). In other examples, the SSB does not involve symbols including both SSS and PBCH signals. One non-limiting example of such an SSB is provided in Figure 1(b).

[0070] The user equipment may comprise multiple antenna panels. The various embodiments disclosed herein can be applied to each antenna panel. Candidate received beams may be evaluated only for the antenna panel currently in use for data transmission / reception, or for one or more other antenna panels. Thus, in some embodiments, the user equipment 600 comprises at least two antenna panels, each having at least two antenna elements, and the beam discovery procedure is performed independently for each of the at least two antenna panels.

[0071] Figure 6 schematically shows the components of a user device 600 according to one embodiment, with respect to several functional units. The processing circuit 610 is provided using one or any combination of a suitable central processing unit (CPU), multiprocessor, microcontroller, digital signal processor (DSP), etc., and can execute software instructions stored in a computer program product 810 (as shown in Figure 8) in the form of a storage medium 630, for example. The processing circuit 610 may further be provided as at least one application-specific integrated circuit (ASIC) or a field-programmable gate array (FPGA).

[0072] In particular, the processing circuit 610 is configured to cause the user device 600 to execute a set of operations or steps, as disclosed above. For example, the storage medium 630 may store a set of operations, and the processing circuit 610 may be configured to retrieve a set of operations from the storage medium 630 in order to cause the user device 600 to execute the set of operations. The set of operations may be provided as a set of executable instructions.

[0073] Accordingly, the processing circuit 610 is configured to perform the methods disclosed herein. The storage medium 630 may also include a persistent storage device which can be any one or combination of, for example, magnetic memory, optical memory, solid-state memory, or further remotely mounted memory. The user device 600 may further include at least a communication interface 620 configured for communication with other entities, functions, nodes, and devices such as access network nodes 220a, 220b, 220c. Accordingly, the communication interface 620 may include one or more transmitters and receivers, including analog and digital components. The processing circuit 610 controls the overall operation of the user device 600, for example, by transmitting data and control signals to the communication interface 620 and the storage medium 630, by receiving data and reports from the communication interface 620, and by retrieving data and instructions from the storage medium 630. Other components and associated functions of the user device 600 are omitted in order not to obscure the concepts presented herein.

[0074] Figure 7 schematically shows the components of a user device 600 according to one embodiment, with respect to several functional modules. The user device 600 in Figure 7 includes several functional modules, namely a receiving module 720 configured to perform step S104 and an inclusion module 730 configured to perform step S106. The user device 600 in Figure 7 may further include several optional functional modules, such as an acquisition module 710 configured to perform step S102 and a selection module 740 configured to perform step S108. Generally speaking, each functional module 710-740 may be implemented in hardware only in one embodiment, or with the help of software in another embodiment, namely, the latter embodiment stores in the storage medium 630 computer program instructions that, when executed on the processing circuit, cause the user device 600 to perform the corresponding steps described above in relation to Figure 7. It should also be noted that even if modules correspond to a part of a computer program, they do not need to be separate modules within it, and the way in which they are implemented in software depends on the programming language used. Preferably, one or more or all of the functional modules 710-740 may be implemented by a processing circuit 610, in part in cooperation with a communication interface 620 and / or a storage medium 630. The processing circuit 610 may therefore be configured to retrieve instructions provided by the functional modules 710-740 from the storage medium 630, execute these instructions, and thereby perform any of the steps disclosed herein.

[0075] Figure 8 shows an example of a computer program product 810 including a computer-readable storage medium 830. A computer program 820 can be stored on this computer-readable storage medium 830, and this computer program 820 can cause the processing circuit 610 and entities and devices operably coupled to the processing circuit 610, such as a communication interface 620 and the storage medium 630, to perform the methods according to the embodiments described herein. Thus, the computer program 820 and / or the computer program product 810 can provide means for performing any of the steps disclosed herein.

[0076] In the example in Figure 8, the computer program product 810 is shown as an optical disc such as a CD (Compact Disc), DVD (Digital Multipurpose Disc), or Blu-ray Disc. The computer program product 810 can also be embodied as a memory such as Random Access Memory (RAM), Read-Only Memory (ROM), Erasable Programmable Read-Only Memory (EPROM), or Electrically Erasable Programmable Read-Only Memory (EEPROM), and more specifically as a non-volatile storage medium in a device within external memory, such as flash memory like a USB (Universal Serial Bus) memory or a miniature flash memory. Thus, although the computer program 820 is schematically shown in this specification as a track on the illustrated optical disc, the computer program 820 can be stored in any way suitable for the computer program product 810.

[0077] The concept of the present invention has been described above primarily with reference to several embodiments. However, as will be readily apparent to those skilled in the art, other embodiments not disclosed herein are equally possible within the scope of the concept of the present invention as defined by the appended claims.

Claims

1. A method for performing a beam discovery procedure relating to a serving access network node (220a), the method being performed by a user device (600), wherein during the beam discovery procedure, the user device (600) evaluates a set of candidate beams based on measurements relating to a set of evaluation symbols, each having at least one evaluation symbol, and the method As part of executing the beam discovery procedure, at least two synchronization signal blocks SSB (100a, 100b) are received (S104), each SSB (100a, 100b) consisting of symbols and received from each access network node (220a, 220b, 220c), one of which is the serving access network node (220a). Each of the at least two SSBs (100a, 100b) includes a primary synchronization signal PSS (110, 110-1, 110-2) and a secondary synchronization signal SSS (130, 130-1, 130-2), wherein in each of the SSBs (100a, 100b), the PSS (110, 110-1, 110-2) includes a PSS sequence, and the SSS (130, 130-1, 130-2) includes an SSS sequence, and all of the SSBs (100a, 100b) have the same PSS sequence but different SSS sequences from each other. When the received power of at least one of the SSSs (130, 130-1, 130-2) of the SSBs (100a, 100b) received from the serving access network node (220a) and the SSSs (130, 130-1, 130-2) of any SSBs (100a, 100b) not received from the serving access network node (220a) satisfies the power-related criteria, the symbol including the PSS (110, 110-1, 110-2) of the SSBs (100a, 100b) received from the serving access network node (220a) is included in the set of evaluation symbols (S106). Methods that include...

2. If the following equation holds true, then the aforementioned power-related standards are met. Here, P ＳＳＳ，０ This is the received power of the SSS (130, 130-1, 130-2) received from the serving access network node (220a), and P ＳＳＳ，κ The method according to claim 1, wherein θ is the received power of the SSS received from an access network node (220b, 220c)κ that does not serve the user device (600), the access network node (220b, 220c)κ has the same PSS sequence as the serving access network node (220a), and θ is a threshold power value.

3. If the following equation holds true, then the aforementioned power-related standards are met. Here, P ＳＳＳ，０ This is the received power of the SSS (130, 130-1, 130-2) received from the serving access network node (220a), and P ≠ 0. ＳＳＳ，κ The method according to claim 1, wherein θ is the received power of the SSS received from an access network node (220b, 220c)κ that does not serve the user device (600), the access network node (220b, 220c)κ has the same PSS sequence as the serving access network node (220a), and θ is a threshold power value.

4. If the following equation holds true, then the aforementioned power-related standards are met. Here, P ＰＳＳ，０ This is the received power of the PSS (110, 110-1, 110-2), and P ＳＳＳ，０ The method according to claim 1, wherein θ is the received power of the SSS (130, 130-1, 130-2) received from the serving access network node (220a), and θ is a threshold power value.

5. The method according to any one of claims 1 to 4, wherein the SSBs (100a, 100b) are received by beams having different beamforming gains, and compensation is performed on the beamforming gains when determining whether the power-related criteria are met.

6. The method according to any one of claims 1 to 4, wherein all SSBs (100a, 100b) are received by beams having equal beamforming gain.

7. The method according to any one of claims 1 to 6, wherein the set of candidate beams is evaluated to determine which of the candidate beams in the set should be used by the user device (600) for communication with the serving access network node (220a).

8. The method according to any one of claims 1 to 7, wherein during the beam discovery procedure, the user instrument (600) performs a beam sweep on the set of candidate beams, and each of the candidate beams receives one of the evaluation symbols and is used for measurement with respect to that evaluation symbol.

9. Executing the aforementioned beam discovery procedure means For communication with the serving access network node (220a), select the candidate beam in which the evaluation symbol is received with the highest received power (S108). The method according to claim 8, further comprising:

10. The aforementioned method, The method according to any one of claims 1 to 9, further comprising obtaining an indication (S102) that the user device (600) is moving at a speed higher than a speed threshold, and executing the beam discovery procedure being triggered in response thereto.

11. The method according to any one of claims 1 to 10, wherein each of the SSBs (100a, 100b) comprises one or more symbols including the PSSs (110, 110-1, 110-2), one or more symbols including the physical broadcast channel PBCH signals (120, 140), and one or more symbols including the SSSs (130, 130-1, 130-2) and the PBCH signals.

12. The method according to any one of claims 1 to 11, wherein the user equipment (600) includes at least two antenna panels, each having at least two antenna elements, and the beam discovery procedure is performed independently for each of the at least two antenna panels.

13. A user device (600) for performing a beam discovery procedure relating to a serving access network node (220a), wherein the user device (600) is configured to evaluate a set of candidate beams based on measurements relating to a set of evaluation symbols, each having at least one evaluation symbol, during the beam discovery procedure, and the user device (600) includes a processing circuit (610), the processing circuit provides the user device (600) with, As part of executing the beam discovery procedure, the process involves receiving at least two synchronization signal blocks SSB(100a, 100b), each SSB(100a, 100b) consisting of symbols, received from their respective access network nodes(220a, 220b, 220c), one of which is the serving access network node(220a). Each of the at least two SSBs (100a, 100b) includes a primary synchronization signal PSS (110, 110-1, 110-2) and a secondary synchronization signal SSS (130, 130-1, 130-2), wherein in each of the SSBs (100a, 100b), the PSS (110, 110-1, 110-2) includes a PSS sequence, and the SSS (130, 130-1, 130-2) includes an SSS sequence, and all of the SSBs (100a, 100b) have the same PSS sequence but different SSS sequences from each other. When the received power of at least one of the SSSs (130, 130-1, 130-2) of the SSB (100a, 100b) received from the serving access network node (220a) and the SSSs (130, 130-1, 130-2) of any SSB (100a, 100b) not received from the serving access network node (220a) satisfies the power-related criteria, the symbol including the PSS (110, 110-1, 110-2) of the SSB (100a, 100b) received from the serving access network node (220a) is included in the set of evaluation symbols. User equipment (600) configured to perform the following actions.

14. A user device (600) for performing a beam discovery procedure relating to a serving access network node (220a), wherein the user device (600) is configured to evaluate a set of candidate beams based on measurements relating to a set of evaluation symbols, each having at least one evaluation symbol, during the beam discovery procedure, and the user device (600) As part of performing the beam discovery procedure, a receiving module (720) is configured to receive at least two synchronization signal blocks SSB (100a, 100b), each SSB (100a, 100b) consisting of symbols and received from each access network node (220a, 220b, 220c), one of which is the serving access network node (220a). Each of the at least two SSBs (100a, 100b) includes a primary synchronization signal PSS (110, 110-1, 110-2) and a secondary synchronization signal SSS (130, 130-1, 130-2), wherein in each of the SSBs (100a, 100b), the PSS (110, 110-1, 110-2) includes a PSS sequence, and the SSS (130, 130-1, 130-2) includes an SSS sequence, and all of the SSBs (100a, 100b) have the same PSS sequence but different SSS sequences, the receiving module (720), When the received power of at least one of the SSSs (130, 130-1, 130-2) of the SSB (100a, 100b) received from the serving access network node (220a) and the SSSs (130, 130-1, 130-2) of any SSB (100a, 100b) not received from the serving access network node (220a) satisfies the power-related criteria, the inclusion module (730) is configured to include the symbols including the PSS (110, 110-1, 110-2) of the SSB (100a, 100b) received from the serving access network node (220a) in the set of evaluation symbols, and User equipment (600), including...

15. A user device (600) according to claim 13 or 14, further configured to perform the method described in any one of claims 2 to 12.

16. A computer program (820) for performing a beam discovery procedure relating to a serving access network node (220a), wherein during the beam discovery procedure, a user device (600) evaluates a set of candidate beams based on measurements relating to a set of evaluation symbols, each having at least one evaluation symbol, and the computer program includes computer code, which, when executed on the processing circuit (610) of the user device (600), provides the user device (600) with: As part of executing the beam discovery procedure, at least two synchronization signal blocks SSB (100a, 100b) are received (S104), each SSB (100a, 100b) consisting of symbols and received from each access network node (220a, 220b, 220c), one of which is the serving access network node (220a). Each of the at least two SSBs (100a, 100b) includes a primary synchronization signal PSS (110, 110-1, 110-2) and a secondary synchronization signal SSS (130, 130-1, 130-2), wherein in each of the SSBs (100a, 100b), the PSS (110, 110-1, 110-2) includes a PSS sequence, and the SSS (130, 130-1, 130-2) includes an SSS sequence, and all of the SSBs (100a, 100b) have the same PSS sequence but different SSS sequences from each other. When the received power of at least one of the SSSs (130, 130-1, 130-2) of the SSBs (100a, 100b) received from the serving access network node (220a) and the SSSs (130, 130-1, 130-2) of any SSBs (100a, 100b) not received from the serving access network node (220a) satisfies the power-related criteria, the symbol including the PSS (110, 110-1, 110-2) of the SSBs (100a, 100b) received from the serving access network node (220a) is included in the set of evaluation symbols (S106). A computer program (820) that performs this task.

17. A computer-readable storage medium (830) in which the computer program (820) described in claim 16 is stored.

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