Method for frequency hopping in PRACH repetition

Abstract

A method is provided, the method comprising: receiving, at a user equipment, a configuration of physical random access channel parameters and frequency hopping parameters from a network control unit; based on the configuration, selecting a starting random access opportunity for a plurality of physical random access channel transmissions; determining a frequency hopping interval of the application based on the configuration and the selected initial random access opportunity; and transmitting the plurality of physical random access channel transmissions from the selected starting random access occasion using frequency hopping based on the determined applied frequency hopping interval.

Description

Technical Field

[0001] The present invention relates to an apparatus, method, and computer program product for providing security in roaming scenarios in edge computing. Background Art

[0002] The following meanings apply to the abbreviations used in this specification: CBRA: Contention-based random access

[0003] DDDSU: Slotted mode (D: downlink, S: dedicated, U: uplink)

[0004] DL: Downlink

[0005] FDM: Frequency Domain Multiplexing

[0006] FH: Frequency Hopping

[0007] FR1: Frequency Range 1

[0008] FR2: Frequency Range 2

[0009] gNB: NR Node B

[0010] ID: Identifier

[0011] Msg1: Message 1

[0012] NR: New Radio

[0013] PBCH: Physical Broadcast Channel

[0014] PRACH: Physical Random Access Channel

[0015] PRB: Physical Resource Block

[0016] PUCCH: Physical Uplink Control Channel

[0017] PUSCH: Physical Uplink Shared Channel

[0018] RACH: Random Access Channel

[0019] RAN: Radio Access Network

[0020] RAR: Random Access Response

[0021] RO: RACH timing

[0022] RNTI: Radio Network Temporary Identifier

[0023] RRC: Radio Resource Control

[0024] SC: Subcarrier

[0025] SIB1: System Information Block 1

[0026] SS / PBCH: Synchronization Signal / Physical Broadcast Channel

[0027] SSB: Synchronization Signal Block

[0028] TC-RNTI: Temporary cell RNTI

[0029] UE: User Equipment

[0030] UL: Uplink

[0031] Example embodiments relate to random access procedures. For example, in 5G NR, two contention-based random access (CBRA) procedures are supported, namely 4-step RACH (Release 15) and 2-step RACH (Release 16).

[0032] Furthermore, example embodiments relate to the possibility of enabling frequency hopping (FH) while transmitting PRACH repetitions in different time instances.Frequency hopping may provide additional gain of PRACH repetitions due to frequency diversity.

[0033] To this end, a framework for FH repetition across PRACHs needs to be provided. Summary of the Invention

[0034] Example embodiments address this situation and aim to provide methods, apparatus and computer programs by which frequency hopping in PRACH repetitions can be provided in a fair manner.

[0035] According to a first aspect, a method is provided comprising:

[0036] At the user equipment, receiving configuration of physical random access channel parameters and frequency hopping parameters from a network control unit;

[0037] selecting, based on the configuration, a starting random access opportunity for transmission of a plurality of physical random access channels;

[0038] Determining an applied frequency hopping interval based on the configuration and the selected starting random access opportunity; and

[0039] A plurality of physical random access channel transmissions are sent from a selected starting random access opportunity using frequency hopping based on the determined applied frequency hopping interval.

[0040] According to a second aspect, a method is provided, comprising: at least one processor and at least one memory comprising computer program code, the at least one memory and the computer program code being configured to, together with the at least one processor, cause the apparatus to at least: receive, at a user equipment, a configuration of physical random access channel parameters and frequency hopping parameters from a network control unit; based on the configuration, select a starting random access opportunity for a plurality of physical random access channel transmissions; based on the configuration and the selected starting random access opportunity, determine an applied frequency hopping interval; and based on the determined applied frequency hopping interval, send a plurality of physical random access channel transmissions from the selected starting random access opportunity using frequency hopping.

[0041] According to a third aspect, a method is provided, comprising:

[0042] configuring physical random access channel parameters for user equipment, and

[0043] Configure frequency hopping parameters for user equipment,

[0044] The frequency hopping parameters include: at least one configured frequency hopping interval to be used by the user equipment to determine an applied frequency hopping interval.

[0045] According to a fourth aspect, an apparatus is provided, comprising: at least one processor and at least one memory comprising computer program code, the at least one memory and the computer code being configured as at least one processor together so that the apparatus at least: configures physical random access channel parameters for a user equipment, and configures frequency hopping parameters for the user equipment, wherein the frequency hopping parameters comprise: at least one configured frequency hopping interval to be used by the user equipment for determining an applied frequency hopping interval. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] These and other objects, features, details and advantages will become more apparent from the following detailed description of example embodiments taken in conjunction with the accompanying drawings, in which:

[0047] Figure 1A shows a UE 1 according to an example embodiment,

[0048] Figure 1B shows a process performed by UE 1 according to an example embodiment,

[0049] Figure 2A shows a gNB 2 according to an example embodiment,

[0050] Figure 2B shows a procedure performed by gNB 2 according to an example embodiment,

[0051] Figure 3 The diagram shows the 4-step RACH process.

[0052] Figure 4 illustrates an example of time domain resource determination for RACH opportunities,

[0053] Figure 5 illustrates an example of SSB to RO mapping with prach-ConfigurationIndex 251 and UL / DL configuration DDSUU,

[0054] Figure 6 illustrates the FH pattern for PUSCH repetition,

[0055] Figure 7 illustrates a grid of valid ROs associated with the same SSB index,

[0056] Figure 8 shows a flow chart when a UE derives an FH interval based on a specified formula according to an example embodiment, and

[0057] Figure 9 Illustrated is a diagram of a device having a plurality of modules connected to a plurality of channels according to an example embodiment. RA =2 RO and n RA =5 for the PRACH repetition of the FH of the two UEs starting from RO. DETAILED DESCRIPTION

[0058] Hereinafter, an exemplary embodiment will be described. However, it should be understood that this description is given by way of example only, and the exemplary embodiment described is by no means to be construed as limiting the present invention thereto.

[0059] Before describing example embodiments, problems of the related art are discussed in more detail below.

[0060] First, the random access procedure is described.

[0061] In particular, in 5G NR, two contention-based random access (CBRA) procedures are supported, namely 4-step RACH (Release 15) and 2-step RACH (Release 16). Some example embodiments focus on the former for illustration purposes and simplicity, but the concepts presented are equally applicable to the latter.

[0062] As in Figure 3 As shown in , the 4-step RACH process can be summarized as follows:

[0063] 1. Msg1 (also known as PRACH): The UE sends a specific preamble to the gNB via the Physical Random Access Channel (PRACH) using a specific resource called RACH Occasion (RO).

[0064] 2. Msg2 (also known as RAR): The gNB responds with a Random Access Response (RAR) that includes the detected preamble ID, timing advance command, TC-RNTI, and an UL grant for transmission of Msg3 on PUSCH.

[0065] 3. Msg3 (also known as RRC request): The UE responds to Msg2 on the scheduled PUSCH using the ID used for contention resolution.

[0066] 4. Msg4 (also known as RRC Establishment): The gNB sends a contention resolution message using the contention resolution ID.

[0067] Upon receiving Msg4, if the UE's contention resolution ID is carried by Msg4, the UE sends an ACK on the PUCCH. This completes the 4-step RACH. It is worth noting that prior to Msg1, there is also a preliminary step of sending and receiving synchronization signal blocks (SSBs), namely DL beam scanning, which is theoretically not part of the RACH process. As a result of the preliminary step, the UE selects the index of the preferred SSB beam and decodes the associated PBCH for MIB, SIB, etc. According to the SSB to RO mapping implicitly conveyed by SIB1, the index is also used by the UE to identify the appropriate RO for the preamble transmission (Msg1).

[0068] It should be noted that this 2-step RACH is similar to the 4-step RACH described above, but Msg1 and Msg3 are combined in MsgA and sent without waiting for feedback from the UE during the transmission process (traditionally Msg2). Similarly, the gNB combines Msg2 and Msg4 into MsgB. The solutions according to some example embodiments for Msg1 can be easily applied to the preamble part / Msg1 part of MsgA.

[0069] Hereinafter, configuration of RACH occasion (RO) is described, wherein first, configuration in the time domain is described.

[0070] The time domain resources for RACH opportunities (RO) are configured by RRC via prach-ConfigurationIndex (in rach-ConfigGeneric), which serves as an indicator for a row of the table specified in TS 38.211 (clause 5.3.2). Using the parameters indicated by prach-ConfigurationIndex, the UE determines the preamble format for PRACH and applies the procedure specified in TS 38.211 (clause 5.3.2) to find the RO in the time domain.

[0071] Figure 4An example of time domain resource determination for a RACH opportunity is shown, where the prach-ConfigurationIndex is 251. When the index is indicated, the UE determines the following:

[0072] - Preamble format C2 shall be used.

[0073] - RO is allocated at the system frame number (n_SFN) that satisfies n_SFN mod 1=0 (ie, all SFN numbers are valid).

[0074] - Within each of the determined SFNs, the RO is allocated at subframe numbers 2 and 7. - Within each of the determined subframes, the remaining parameters in the considered row indicate that the RO will start at symbol numbers 0, 6, 14, 20. This symbol number is counted consecutively regardless of the number of slots within the subframe, which depends on the subcarrier spacing configured for PRACH.

[0075] The RO duration is 6 symbols (although the actual duration of the preamble format may be less than this).

[0076] Finally, the validity of the determined RO is checked. According to TS 38.213 (clause 8.1), in case the RO is within a flexible symbol, the RO is determined to be valid if it is within a UL symbol or if it has a sufficient gap after the last SSB / DL symbol.

[0077] Hereinafter, configuration in the frequency domain is described.

[0078] The parameters Msg1-FrequencyStart and Msg1-FDM configured in RACH-ConfigGeneric indicate the offset of the lowest RO in the frequency domain from the start of the UE uplink bandwidth part and the number of ROs multiplexed in the frequency domain for each time instance, respectively. Such ROs are indexed as n RA = {0, 1, ..., M-1}, where M is equal to the higher layer parameter Msg1-FDM and is numbered in increasing order starting from the lowest frequency domain in the UE uplink bandwidth part. Examples of such mappings are also given in Figure 5 , which illustrates an example of SSB to RO mapping using prach-ConfigurationIndex 251 and UL / DL configuration DDDSU in the case of Msg1-FDM=2

[0079] The number of occupied resource blocks per RO, expressed in terms of the number of RBs used for PUSCH, is specified in section 6.3.3.2 of TS 38.211, depending on the configured preamble length and the subcarrier spacing used for PRACH and PUSCH.

[0080] In the following, SSB to RO mapping is described.

[0081] The mapping of SSB indices to determined ROs is essential for the UE to understand which RO is associated with the selected SSB index during the preliminary steps before the start of the RACH procedure. Different SSB indices are beamformed in different directions in a cell, so the selection of an incorrect SSB index can cause the RACH procedure to fail.

[0082] For this purpose, a basic parameter ssb-perRACH-OccasionAndCB-PreamblesPerSSB is configured in RACH-ConfigCommon and indicates two pieces of information: (i) the number of SSB indices per RO and (ii) the number of contention-based preambles per SSB index. Once this information is available to the UE, the UE maps the SSB index to the time domain grid of the RO (determined as described above) in ascending order of the frequency resource index, the time resource index of the RO within the PRACH slot, and the PRACH slot.

[0083] Figure 5 The diagram shows Figure 4 The example of the valid RO in one subframe determined as illustrated in FIG is also assumed, and the following additional configuration is also assumed: DDDSU time slot structure, Msg1-FDM=2, and ssb-perRACH-OccasionAndCB-PreamblesPerSSB is half. Based on this configuration, two ROs are multiplexed in the frequency domain (Msg1-FDM=2), and any two frequency-division multiplexed ROs (i.e., two ROs multiplexed in the frequency domain) are mapped to the same SSB index (ssb-perRACH-OccasionAndCB-PreamblesPerSSB=1 / 2). The original ROs #4, #5, #6, and #7 are prohibited from being considered valid because they are within the DL symbol.

[0084] Frequency hopping is defined in the 3GPP specification (TS 38.214) for PUSCH repetition as described below:

[0085] "In case of inter-slot hopping and when PUSCH-DMRS-Bundling is not enabled, or for inter-slot hopping for PUSCH scheduled by RAR UL grant or DCI format 0_0 with CRC scrambled by TC-RNTI, in slot The starting RB of the period is given by:

[0086]

[0087] in is the current slot number within the system radio frame where multislot PUSCH can occur, RB start is the starting RB within the ULBWP calculated according to the resource block allocation information of resource allocation type 1 (as described in clause 6.1.2.2.2), and RB offset is the frequency offset in RBs between two frequency hops."

[0088] In other words, when repeatedly UE hopping between two hopping frequencies in an alternating manner (so-called frequency hopping (FH) pattern), the two hopping frequencies are separated in frequency by a frequency offset (also referred to in this application as frequency hopping interval or FH interval).

[0089] A simple example of FH mode is Figure 6 , where each box represents a resource block (RB) and each grey box represents a PUSCH repetition (assuming only one RB is allocated). In this case, the UE follows FH mode with an RB offset of 3 RBs and 4 PUSCH repetitions.

[0090] To explain the problems solved according to some example embodiments, refer to Figure 7 , which represents a grid of valid ROs (each box is a RO), all valid ROs are associated with the same SSB index, and where the horizontal domain represents time and the vertical domain represents frequency. Even though the ROs are represented as continuous in time and frequency for the purpose of representation, it is not a requirement for the example embodiments. In each box, a specific UE may be present, each UE is assumed to start at the first time instance (first column), and each UE performs 4 repetitions at different time instances, each repetition in the RO is at a different frequency (and therefore a different n) than the previous repetition (i.e., frequency hopping). RA In this example, it has been shown how four different UEs, namely UE-A, UE_B, UE_C and UE_D, perform repetitions at different frequencies in different time instances.

[0091] In this example, a certain mode of operation for frequency hopping is assumed. More specifically, it is assumed that 1 RO (or 1 nRA The hopping interval of the RO is configured, and each UE determines two hops for PRACH repetition: in a modular operation, at the beginning of the RO RA on the first hop and as the distance from the first hop to n RA (higher frequency). For example, for UE_A, the first hop is at n RA = 0 and the second jump is at n RA = 1. The latter constraint (modulo operation) is specifically related to UE_D, which cannot jump to a higher RO, so it jumps to the lowest RO of the grid (i.e. the second hop for UE_D should be at n RA =4, because the first hop is at n RA =3, but due to n RA =4 does not exist, UE_D is in n RA =0 is sent as the second hop, n RA = 0 is the result of the modular operation). Therefore, compared with the other three UEs, UE_D will be able to enjoy more frequency diversity (the first hop and the second hop are more spaced apart in frequency). RA = 3 is selected as the starting RO for PRACH repetition, which produces a performance advantage, but risks inducing the UE implementation to always select this RO as the starting RO for PRACH repetition transmission, which in turn increases the collision probability for PRACH repetition. In addition, in order to avoid increasing the false alarm probability of PRACH repetition, the FH pattern needs to be designed so that the ROs of different FH patterns do not overlap, so that UE_D cannot select n RA As a second jump.

[0092] Based on the above, a method for enabling fair and exclusive hopping patterns (i.e., fair means all have the same degree of frequency diversity and exclusive means not overlapping with each other) that results in a fair and exclusive FH pattern regardless of the RO selected as the starting RO is necessary, and this method will be the focus of some example embodiments described below.

[0093] According to some example embodiments, a procedure is proposed by which frequency hopping across PRACH repetitions is enabled, which results in a fair and exclusive FH pattern regardless of the starting RO selected for the PRACH repetitions.

[0094] In the following, a general overview of some example embodiments is given by reference to Figure 1A 、 1B , 2A and 2B are described.

[0095] Figure 1AUE 1 according to this exemplary embodiment is shown. The UE 1 is an example of an apparatus, which may be, for example, a user equipment or may be a part of a user equipment. A program executed by the UE is Figure 1B In the diagram. Figure 1A The UE 1 shown in FIG comprises at least one processor 11 and at least one memory 12 including computer program code. The at least one processor 11 together with the at least one memory 12 and the computer program code is configured to cause the apparatus to execute: receiving a request from a network control unit (e.g., Figure 2A The gNB 2) receives the configuration of the physical random access channel (PRACH) parameters and frequency hopping parameters (in Figure 1B Based on the configuration, selecting a starting random access opportunity (RO) for multiple physical random access channel (PRACH) transmissions (in Figure 1B Based on the configuration and the selected starting random access opportunity, determine the frequency hopping interval (FH interval )(exist Figure 1B and based on the determined frequency hopping interval of the application, (using frequency hopping) sending multiple physical random access channels (PRACH) from the selected starting random access opportunity ( Figure 1B S14 in ).

[0096] Figure 2A FIG2 shows a gNB 2 according to this example embodiment. The gNB 2 is an example of an apparatus, which may be, for example, a network element or a part of a network element. The process performed by the gNB 2 is shown in FIG2. Figure 2B In the diagram. Figure 2A The gNB 2 shown in FIG. 1 comprises at least one processor 21 and at least one memory 22 including computer program code. The at least one processor 21 together with the at least one memory 22 and the computer program code is configured to cause the apparatus to perform: configuring physical random access channel (PRACH) parameters for user equipment (in Figure 2B and configuring frequency hopping parameters for user equipment (in S21); Figure 2B S22 in the step, wherein the frequency hopping parameters include: a frequency hopping interval (FH) to be used by the user equipment to determine an application interval ) of at least one configured frequency hopping interval (FH config ).

[0097] Thus, according to an example embodiment, the UE is configured with PRACH parameters and FH parameters, based on which the starting RO and the applied (actual) frequency hopping (FH) interval are determined. In this way, frequency hopping across PRACH repetitions with a fair and exclusive hopping pattern can be provided, regardless of the starting RO selected for the PRACH repetition.

[0098] It should be noted that according to some example embodiments, a frequency hopping (FH) interval defines the distance in frequency (ie, frequency hops) between one repetition and the next.

[0099] It should be noted that the term frequency hopping interval may also be referred to as frequency offset.The frequency hopping (FH) interval or frequency offset indicates the difference in frequency between two frequency hops.

[0100] It should be noted that the (actual) hopping interval applied may be set to different values ​​depending on the configured hopping parameters. This may include zero, effectively causing the UE to not perform hopping across PRACH repetitions.

[0101] For example, the hopping interval may also be set to zero so that no hopping is performed for that instant. For example, another configuration information of the frequency hopping configuration parameter may include a value that, based on the selected starting RO, instructs the user equipment to set the applied hopping interval to the configured hopping interval or to zero. This may be done in the form of a bitmap (e.g., [1 0 10], etc.), where each bit of the bitmap refers to a different starting RO for PRACH repetition, where, for example, 1 indicates that the user equipment sets the applied hopping interval to the configured hopping interval, and 0 indicates that the user equipment (UE) sets the applied hopping interval to zero.

[0102] Alternatively, such a bitmap may be used to either indicate that the applied hopping interval is to be set to the configured hopping interval, or to its inverse.

[0103] Alternatively, such a bitmap may be used to either indicate that the applied hopping interval is set to the opposite of the configured hopping interval, or to zero.

[0104] Alternatively, such a bitmap may be used to either indicate that the applied frequency hopping interval is set to a value related to the configured frequency hopping interval, or to zero.

[0105] This bitmap can exist in the form of a vector.

[0106] Figure 1A and Figure 2A The arrangement shown in may comprise more components than described above and may also comprise I / O units 13, 23, which are able to send to and receive from other network elements.

[0107] In the following, the process described above is described in some more detail with reference to some more detailed embodiments.

[0108] As described above, some example embodiments propose methods for enabling frequency hopping across PRACH repetitions (e.g., as described above in conjunction with Figure 7 ), which results in a fair and exclusive FH pattern regardless of the starting RO selected for PRACH repetitions. In particular, conditions are proposed that the frequency hopping configuration and the frequency hopping interval satisfy to ensure that the UE can obtain the same degree of frequency diversity while transmitting on the exclusive pattern, resulting in a fair and exclusive FH pattern regardless of the starting RO selected for PRACH repetitions.

[0109] In the following, configuration of frequency hopping parameters for PRACH repetitions according to some example embodiments is described.

[0110] In particular, according to an exemplary embodiment, which is hereinafter referred to as embodiment 1a, a UE is configured with multiple frequency hopping intervals (FH config ), the multiple frequency hopping intervals define the distance in frequency (i.e. hops) between one repetition and the next, and the applied (actual) frequency hopping interval (FH interval ) is determined by the UE based on the configuration. It should be noted that the frequency hopping interval (FH) configured by the network (e.g., by the gNB) config ) is also referred to as the "configured FH interval" or "configured frequency hopping interval", and the actual frequency hopping interval is also referred to as the "applied frequency hopping interval".

[0111] If the number of repetitions is indicated as N, the number of hopping intervals is equal to or less than N-1. If equal to N-1, one hopping interval is mapped to a bundle of repetitions characterized by two consecutive repetitions (in any case, this does not mean that the repetitions are actually consecutive in time). Conversely, if less than N-1, one hopping interval is mapped to a bundle of repetitions characterized by more than two repetitions. For example, if N=8, but only 2 hopping intervals are configured, each interval is then mapped to a bundle of 4 repetitions, meaning that the same hop is performed between the 1st and 2nd repetitions, between the 2nd and 3rd repetitions, and between the 3rd and 4th repetitions, and the same, but possibly different, hop is performed between the 4th and 5th repetitions, between the 5th and 6th repetitions, between the 6th and 7th repetitions, and between the 7th and 8th repetitions.

[0112] The configured multiple hopping intervals may be the same if resulting in a fair and exclusive FH pattern regardless of the RO (in time) selected for PRACH repetitions, or may be specific to the starting RO (in time) for PRACH repetitions.

[0113] According to another embodiment, which may be referred to as embodiment 1b hereinafter, for example based on embodiment 2 and its variants described later, the UE is configured with only one frequency hopping interval (FH) for all repetitions N. config ), and the applied (actual) frequency hopping interval (FH interval ) is determined by the UE. In this case, the first hop of the FH mode (in n RA (unit) by the starting RO n RA Index (also referred to as n in the following) RA_start ) is provided, where the second hop of the FH mode is calculated as n RA_start +FH interval .

[0114] According to another embodiment, which is hereinafter referred to as embodiment 1c, the UE is configured with one or more starting ROs for PRACH repetitions with frequency hopping. In other words, and with reference to for example Figure 7 , not all ROs in the first time instance (first column) will allow frequency hopping across PRACH repetitions, but the UE may perform frequency hopping only when starting from a subset of such ROs.

[0115] The configuration according to this embodiment can be in the form of a bitmap of a length equal to the number of ROs multiplexed in the frequency domain and mapped to the same SSB index, where "one" represents the starting RO for PRACH repetition with frequency hopping and "zero" represents the starting RO for PRACH repetition without frequency hopping.

[0116] Alternatively, the configuration according to this embodiment may be performed with n less than or equal to the length of multiplexed in the frequency domain and mapped to the same SSB index. RA The index is in the form of a vector, where n RA The index represents the n associated with the starting RO for PRACH repetition with frequency hopping RA index.

[0117] Alternatively, the configuration may be in the form of an n RA Index and length value L RA The form of, and the UE will use the starting RO for PRACH repetition with frequency hopping n RA Index is exported as RA and n RA +L RA All n between -1 RA index.

[0118] According to another embodiment, which is hereinafter referred to as embodiment 1d, the UE determines the configured frequency hopping interval(s) (FH configFor example, the UE considers the configured frequency hopping interval(s) to be valid when they meet certain conditions.

[0119] If the CHOICE portion of the ssb-perRACH-OccasionAndCB-PreamblesPerSSB field in RACH-ConfigCommon is less than one, then let's call M its inverse. In one embodiment, hereinafter referred to as embodiment 1d1, the configured frequency hopping interval (s) is valid only when the ratio between min(M, K) and the configured frequency hopping interval (s) is an even number. Here, K is the number of one or more starting ROs for the configuration of PRACH repetitions with FH, as described above by embodiment 1c.

[0120] If the CHOICE part of the field ssb-perRACH-OccasionAndCB-PreamblesPerSSB in RACH-ConfigCommon is greater than one, let us call M its inverse. In one embodiment, which is hereinafter referred to as embodiment 1d2, the configured frequency hopping interval(s) is valid only when the ratio between f(M) and the configured frequency hopping interval(s) is an even number, where

[0121]

[0122] In addition, Msg1-FDM is a parameter configured in RACH-ConfigCommon, and #SSBindexes is the total number of configured SSB indices. Here, K is the number of one or more starting ROs for configuration of PRACH repetition with FH, as described above by embodiment 1c.

[0123] According to embodiments 1d1 and 1d2 described above, the invalid frequency hopping configuration disables UE frequency hopping across PRACH repetitions.

[0124] According to another embodiment, which is referred to as embodiment 1e in the following, a valid configured frequency hopping interval according to embodiment 1d enables PRACH repetition in the cell. Conversely, an invalid frequency hopping configuration disables PRACH repetition in the cell.

[0125] According to another embodiment, which is hereinafter referred to as embodiment 1f, the unit of the configured (multiple) frequency hopping intervals may be a subcarrier (SC), a physical resource block (PRB), or an index n RA .

[0126] According to another embodiment, which is referred to as embodiment 2 in the following, a UE determination of the actual hopping spacing(s) based on at least one of the configuration and the starting RO for PRACH repetition is described.

[0127] In particular, according to another embodiment, hereinafter referred to as embodiment 2a, the applied (actual) frequency hopping intervals (FH interval ) is the hopping interval(s) used by the UE for hopping across PRACH repetitions.

[0128] According to another embodiment, hereinafter referred to as embodiment 2b, in the case where multiple frequency hopping intervals are configured, the UE sets the FH interval =FH config To determine the actual FH interval based on the configuration, where FH config are multiple frequency hopping intervals configured according to embodiments 1a to 1f described above.

[0129] According to another embodiment, hereinafter referred to as embodiment 2c, in case only one FH interval is configured, the UE determines the actual FH interval based on the configuration and the starting RO for PRACH repetition. In this case, the first hop of the FH pattern (in n RA (unit) by the starting RO n RA Index(n RA_Start ) is provided, however the second hop in FH mode is calculated as n RA_Start +FH interval If we enumerate the repetitions from 1 to N, the UE transmits with odd-numbered repetitions in the first hop and transmits with even-numbered repetitions in the second hop.

[0130] According to one embodiment, which is hereinafter referred to as embodiment 2d, for the case of only one configured FH interval, the determination of the actual frequency hopping interval is based on a specific formula:

[0131]

[0132] where n RA_Start is the n of the starting RO RA Index, FH config is the configured frequency hopping interval and mod is the modulo operation.

[0133] According to another embodiment, hereinafter referred to as embodiment 2e, for the case of only one configured FH interval, the determination of the actual frequency hopping interval is based on an additional configuration of a vector of values ​​from the gNB, the vector having a length equal to the number of ROs frequency-division multiplexed and mapped to the same SSB index.

[0134] In particular, according to one implementation, the vector is a bitmap where a value of 1 indicates that the UE willinterval Set to the configured value FH config And the value 0 indicates that the UE will FH interval Set to the opposite of the configured value (i.e. -FH config ).

[0135] According to another implementation, the vector is a bitmap, where a value of 0 indicates that the UE will interval Set to the configured value FH config And the value 1 indicates that the UE will FH interval Set to the opposite of the configured value (i.e. -FH config ).

[0136] According to another implementation, the vector includes an instruction for the UE to transfer FH interval Set to the configured value FH interval , or set to the opposite value of the configured value (ie -FH config ).

[0137] In the following, an example implementation of the proposed process is given by reference to Figure 8 Rather, another example embodiment is described.

[0138] In procedures P1A and P1B, UE configuration of PRACH parameters and frequency hopping parameters from the gNB is performed. Figure 8 In the example shown in FIG, in process P1A, the configuration of PRACH parameters is performed, and in process P1B, the configuration of frequency hopping parameters for PRACH repetition (eg, including the frequency hopping parameters for the starting RO and FH) is performed. config It should be noted that even though they are shown as two different processes in the flowchart, they can be configured at the same time (as process P1) or not in the order shown in the flowchart.

[0139] PRACH parameters include parameters for determining PRACH resources in terms of RACH occasions (RO) and preamble formats for PRACH transmission.FH parameters for PRACH repetition include at least one or more FH intervals and one or more starting ROs for PRACH repetitions with FH.

[0140] In this example, only one FH interval and the bitmap for the starting RO are configured without loss of generality.

[0141] For example, if 4 ROs are multiplexed in the frequency domain and are associated with the same SSB index, the bitmap has a size of 4 bits, with each bit representing one RO. For example, an entry with a value of 1 represents the starting RO for PRACH with FH, while an entry with a value of 0 represents the starting RO for PRACH repetition without FH.

[0142] In procedure P2, the UE selects the starting RO in a random manner among the configured starting ROs for PRACH repetition with FH. For example, the configured starting RO is conveyed by the bitmap [1 1 00 1 1 1 1], with n from 0 to 7 RA The ROs are multiplexed in the frequency domain and are associated with the same SSB index (8 ROs are multiplexed in the frequency domain and are associated with the same SSB index).

[0143] For example, the UE randomly selects n RA =5 as the starting RO.

[0144] Furthermore, it is assumed that the time instance of the starting RO is known to the UE.

[0145] In process P3, the UE uses the configured FH interval (FH config )) and the selected starting RO based on the following formula to derive the actual FH interval (FH interval )

[0146]

[0147] For example, in the first example, if the selected starting RO is a RA_Start = 5 (as by the previous step) and FH config = 4 RO, then FH interval =-FH config .

[0148] In the second example, if the selected starting RO is a RA_Start = 0 (as by the previous step) and FH config = 4 RO, then FH interval =FH config .

[0149] In the third example, if the selected starting RO is a RA_Start = 2 (as in the previous step), the UE does not perform FH according to the configured bitmap and sends RA =2 for all four PRACH repetitions.

[0150] Alternatively, in process P3, the UE may perform a FH interval based on the configured FH interval (FH config) and the selected starting RO, and derives the actual FH interval (FH based on the configured bitmap of the starting RO interval ). Specifically, if the value of the bitmap is 1, the UE sets the actual FH interval to the configured FH interval, whereas if the value of the bitmap is 0, the UE sets the actual FH interval to 0 and does not perform FH.

[0151] For example, in the first example, if the selected starting RO is a RA_Start = 5 RO (as determined by the previous step), then FH interval =FH config .

[0152] In the second example, if the starting RO selected is a RA_Start = 2 RO (as determined by the previous step), then FH interval = 0 and UE does not perform FH and sends RA =2 for all four PRACH repetitions.

[0153] In procedure P4, if the starting RO allows frequency hopping based on the configured bitmap, the UE transmits PRACH from the selected starting RO and utilizes the FH pattern based on the derived actual (applied) FH interval.

[0154] For example, if the starting RO selected is a RA =5 and FH config = 4 RO, which gives FH interval =-4 (the first example described above), then the UE follows n RA Pattern {5, 1, 5, 1}.

[0155] For example, if the starting RO selected is a RA =0 and FH config = 4 RO, which gives FH interval =4 (the second example described above), the UE follows n RA Pattern {0,4,0,4}

[0156] These embodiments are Figure 9 It is further shown in , where UE_A is the UE of the first example, UE_B is the UE of the second example, and UE_C is the UE of the third example.

[0157] Thus, according to some example embodiments, methods are provided for enabling frequency hopping across PRACH repetitions with fair and exclusive hopping patterns, regardless of which starting RO is selected for the PRACH repetitions. In particular, according to some example embodiments, conditions are provided for the frequency hopping configuration and the frequency hopping interval to satisfy to ensure that a UE can obtain the same degree of frequency diversity while transmitting on an exclusive pattern, regardless of the starting RO selected for the PRACH repetitions.

[0158] The exemplary embodiments described above are merely examples and may be modified.

[0159] According to a first aspect of an example embodiment, a method in a user equipment is provided, the method comprising:

[0160] At the user equipment, receiving configuration of physical random access channel parameters and frequency hopping parameters from a network control unit;

[0161] Based on the configuration, a starting random access opportunity for a plurality of physical random access channel transmissions is selected.

[0162] Based on the configuration and the selected starting random access opportunity, determining an applied frequency hopping interval; and

[0163] Based on the determined applied frequency hopping interval, multiple physical random access channel transmissions are sent (using frequency hopping) from the selected starting random access opportunity.

[0164] According to a second aspect, an apparatus is provided, comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to at least:

[0165] At the user equipment, receiving configuration of physical random access channel parameters and frequency hopping parameters from a network control unit;

[0166] selecting, based on the configuration, a starting random access opportunity for transmission of a plurality of physical random access channels;

[0167] Based on the configuration and the selected starting random access opportunity, determining an applied frequency hopping interval; and

[0168] Based on the determined applied frequency hopping interval, a plurality of physical channel access parameter transmissions are sent (using frequency hopping) from the selected starting random access opportunity.

[0169] The first and second aspects can be modified as follows:

[0170] The frequency hopping parameters may include a configured frequency hopping interval, and the method may further include:

[0171] Based on the configured frequency hopping interval and the selected starting random access opportunity, the applied frequency hopping interval is determined.

[0172] The frequency hopping parameters may include a configured frequency hopping interval, and the at least one memory and the computer program code are configured to, together with the at least one memory, cause the apparatus to determine an applied frequency hopping interval based at least on the configured frequency hopping interval and a configured starting random access occasion.

[0173] The applied frequency hopping interval can be determined based on the following formula:

[0174]

[0175] where n RA_Start is the selected starting random access opportunity n RA Index, FH config is the configured frequency hopping interval, and mod is the modulus operation

[0176] The method further includes:

[0177] Determine if the configured hopping interval is valid, and

[0178] Disable frequency hopping when it is determined that the configured frequency hopping interval is invalid, or

[0179] Frequency hopping is enabled upon determining that the configured frequency hopping interval is valid.

[0180] The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least determine whether a configured frequency hopping interval is valid, and disable frequency hopping when it is determined that the configured frequency hopping interval is invalid, or enable frequency hopping when it is determined that the configured frequency hopping interval is valid.

[0181] The physical random access channel parameters may include at least one starting random access opportunity.

[0182] The physical random access channel parameters may include a plurality of starting random access opportunities, and the method may further include:

[0183] The selected starting random access opportunity is randomly selected from a plurality of starting random access opportunities.

[0184] The physical random access channel parameters may include the number of physical random access channel repetitions.

[0185] The frequency hopping parameters may include: a configured frequency hopping interval, and another configuration information including a value indicating that the user equipment sets the applied frequency hopping interval to the configured frequency hopping interval or to the inverse of the configured frequency hopping interval based on the selected starting random access opportunity.

[0186] Another configuration information may include a vector in which values ​​are included, wherein the vector may include a length equal to the number of random access opportunities of frequency division multiplexing.

[0187] The vector may be a bitmap, each bit of the bitmap referring to a different starting random access opportunity (starting RO of a PRACH repetition), and a first value of each bit (e.g., 1 or 0) indicating that the user equipment sets the applied frequency hopping interval to the configured frequency hopping interval, and a second value of each bit (e.g., 0 or 1) indicating that the user equipment sets the applied frequency hopping interval to the opposite value of the configured frequency hopping interval.

[0188] The frequency hopping parameters may include: a configured frequency hopping interval, and further configuration information including a value indicating that the user equipment sets the applied frequency hopping interval to the configured frequency hopping interval or to zero based on the selected starting random access opportunity. Therefore, it should be noted that the further configuration information indicates whether the UE performs frequency hopping based on the configured frequency hopping interval or does not perform frequency hopping based on the selected starting random access opportunity (equivalent to setting the applied frequency hopping interval to zero).

[0189] Another configuration parameter may be in the form of a bitmap, each bit of the bitmap referring to a different starting RO of PRACH repetition, wherein the first value of each bit (e.g., 1 or 0) indicates that the user equipment sets the applied frequency hopping interval to the configured frequency hopping interval, and the second value of each bit (e.g., 0 or 1) indicates that the user equipment sets the applied frequency hopping interval to 0.

[0190] According to a third aspect of some example embodiments, a method in a network control element is provided, the method comprising:

[0191] configuring physical random access channel parameters for user equipment, and

[0192] Configure frequency hopping parameters for user equipment,

[0193] The frequency hopping parameters include at least one configured frequency hopping interval to be used by a user to determine an applied frequency hopping interval.

[0194] According to a fourth aspect of some example embodiments, an apparatus is provided, comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code being configured, with the at least one processor, such that the apparatus at least:

[0195] configuring physical random access channel parameters for user equipment, and

[0196] Configure frequency hopping parameters for user equipment,

[0197] The frequency hopping parameters include: at least one configured frequency hopping interval to be used by the user equipment for determining an applied frequency hopping interval.

[0198] The third and fourth aspects can be modified as follows:

[0199] The physical random access channel parameters may include information about at least one starting random access opportunity.

[0200] The frequency hopping parameters may include the number of physical random access channel repetitions.

[0201] The frequency hopping parameters may include a configured frequency hopping interval, and further configuration information including a value indicating that the user equipment sets the applied frequency hopping interval to the configured frequency hopping interval or to the inverse of the configured frequency hopping interval.

[0202] The further configuration information may include a vector in which values ​​are included, wherein the vector may include a length equal to the number of random access opportunities of frequency division multiplexing.

[0203] The vector may be a bitmap, and the first value of each bit (e.g., 1 or 0) may indicate that the user equipment sets the applied frequency hopping interval to the configured frequency hopping interval, and the second value of each bit (e.g., 0 or 1) may indicate that the user equipment sets the applied frequency hopping interval to the opposite value of the configured frequency hopping interval.

[0204] The frequency hopping parameter may include: a configured frequency hopping interval, and further configuration information including a value indicating that the user equipment sets the applied frequency hopping interval to the configured frequency hopping interval or to zero.

[0205] The value of the other configuration information can be in the form of a bitmap, where the first value of each bit (e.g., 1 or 0) indicates that the user equipment sets the applied frequency hopping interval to the configured frequency hopping interval, and the second value of each bit (e.g., 0 or 1) indicates that the user equipment sets the applied frequency hopping interval to zero.

[0206] According to a fifth aspect of some example embodiments, a computer program product is provided, comprising code means for executing, when executed on a processing means or module, a method according to any one of the first and third aspects and / or modifications thereof. The computer program product may be embodied on a computer-readable medium, and / or the computer program product may be directly loadable into an internal memory of a computer and / or transmittable via a network by at least one of an upload process, a download process, and a push process.

[0207] According to a sixth aspect of some example embodiments, an apparatus is provided, comprising:

[0208] means for receiving, at a user equipment, a configuration of physical random access channel parameters and frequency hopping parameters from a network control unit;

[0209] means for selecting a starting random access opportunity for a plurality of physical random access channel transmissions based on the configuration;

[0210] means for determining an applied frequency hopping interval based on the configuration and the selected starting random access opportunity; and

[0211] for sending a plurality of physical random access channel transmissions from a selected starting random access opportunity using frequency hopping based on the determined applied frequency hopping interval.

[0212] According to a seventh aspect, an apparatus is provided, comprising:

[0213] means for configuring physical random access channel parameters for user equipment, and

[0214] means for configuring frequency hopping parameters for a user equipment,

[0215] The frequency hopping parameters include: at least one configured frequency hopping interval to be used by the user equipment for determining an applied frequency hopping interval.

[0216] The names of network elements, protocols and methods are based on current standards. In other versions or other technologies, the names of these network elements and / or protocols and / or methods can be different, as long as they provide corresponding functions.

[0217] In general, the example embodiments may be implemented by computer software that is stored in the memory (memory resources, memory circuitry) 12, 22 and that may be executed by the processor (processing resources, processing circuitry) 11, 21 or by hardware, or by a combination of software and / or firmware and hardware.

[0218] As used in this application, the term "circuitry" refers to all of the following:

[0219] (a) hardware circuit implementations only (such as implementations in analog circuitry and / or digital circuitry only) and

[0220] (b) a combination of circuitry and software (and / or firmware), such as (as applicable): (i) a combination of processor(s) or (ii) portions of processor(s) / software (including digital signal processor(s), software, and memory(s) that work together to enable a device such as a mobile phone or server to perform various functions) and

[0221] (c) Circuitry, such as microprocessor(s) or portion(s) of microprocessor(s), that requires software or firmware for operation even if the software or firmware is not physically present.

[0222] This definition of "circuitry" applies to all uses of this term in this application, including in any claims. As another example, as used in this application, the term "circuitry" would also cover an implementation of merely a processor (or multiple processors) or portion of a processor and its (or their) accompanying software and / or firmware. For example, the term "circuitry" would also cover a baseband integrated circuit or an applications processor integrated circuit for a mobile phone or a similar integrated circuit in a server, cellular network device, or other network device, if applicable to the particular claim element.

[0223] The terms "connected," "coupled," or any variations thereof, mean any connection or coupling, either direct or indirect, between two or more elements, and may encompass the presence of one or more intermediate elements between two elements that are "connected" or "coupled" together. The coupling between elements may be physical, logical, or a combination thereof. As used herein, two elements may be considered to be "connected" or "coupled" together through the use of one or more wires, cables, and printed electrical connections, as well as through electromagnetic energy, such as electromagnetic energy having wavelengths in the radio frequency region, the microwave region, and the optical (both visible and invisible) region, as non-limiting examples.

[0224] The memories (memory resources, memory circuitry) 12, 22 may be of any type suitable for the local technical environment and may be implemented using any suitable data storage technology (such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed and removable memory, and non-transitory computer-readable media). As non-limiting examples, the processors (processing resources, processing circuitry) 11, 21 may be of any type suitable for the local technical environment and may include one or more of a general-purpose computer, a special-purpose computer, a digital signal processor (DSP), and a processor based on a multi-core processor architecture.

[0225] It should be understood that the above description is illustrative of the present invention and should not be construed as limiting the present invention. Various modifications and applications may occur to those skilled in the art without departing from the true spirit and scope of the present invention as defined by the appended claims.

Claims

1. A method in a user equipment, the method comprising: At the user equipment, receiving configuration of physical random access channel parameters and frequency hopping parameters from a network control unit; selecting, based on the configuration, a starting random access opportunity for transmission of a plurality of physical random access channels; Determining an applied frequency hopping interval based on the configuration and the selected starting random access opportunity; as well as The plurality of physical random access channel transmissions are sent from the selected starting random access opportunity based on the determined applied frequency hopping interval.

2. The method according to claim 1, wherein the frequency hopping parameter comprises a configured frequency hopping interval, the method further comprising: The applied frequency hopping interval is determined based on the configured frequency hopping interval and the selected starting random access opportunity.

3. The method according to claim 2, wherein the applied frequency hopping interval is determined based on the following formula: where n RA_Start is the selected starting random access opportunity n RA Index, FH config is the configured frequency hopping interval, and mod is the modular operation.

4. The method according to claim 2 or 3, further comprising: determining whether the configured frequency hopping interval is valid, and disabling frequency hopping upon determining that the configured frequency hopping interval is invalid, or Frequency hopping is enabled when it is determined that the configured frequency hopping interval is valid.

5. The method according to any one of claims 1 to 4, wherein the configuring comprises: At least one starting random access opportunity.

6. The method according to any one of claims 1 to 5, wherein the configuring comprises: A plurality of starting random access opportunities, and the method further comprises: The selected starting random access opportunity is randomly selected from the plurality of starting random access opportunities.

7. The method according to any one of claims 1 to 6, wherein the physical random access channel parameters include: Number of repetitions of the physical random access channel parameter.

8. The method according to any one of claims 1 to 7, wherein the frequency hopping parameters include: A configured frequency hopping interval, and further configuration information, the further configuration information comprising a value indicating that the user equipment sets the applied frequency hopping interval to the configured frequency hopping interval or to the inverse of the configured frequency hopping interval based on the selected starting random access opportunity.

9. The method according to claim 8, wherein the another configuration information comprises: The value is included in a vector, wherein the vector includes a length equal to the number of random access opportunities of frequency division multiplexing.

10. The method of claim 9, wherein the vector is a bitmap, each bit of the bitmap refers to a different starting random access event, and a first value of each bit indicates that the user equipment sets the applied frequency hopping interval to the configured frequency hopping interval, and a second value of each bit indicates that the user equipment sets the applied frequency hopping interval to the opposite value of the configured frequency hopping interval.

11. The method according to any one of claims 1 to 7, wherein the frequency hopping parameters include: A configured frequency hopping interval, and further configuration information, wherein the further configuration information comprises a value indicating that the user equipment sets the applied frequency hopping interval to the configured frequency hopping interval or to zero based on the selected starting random access opportunity.

12. The method according to claim 11, wherein the value of the other configuration information is in the form of a bitmap, each bit of the bitmap refers to a different starting random access opportunity, wherein the first value of each bit indicates that the user equipment sets the frequency hopping interval of the application to the configured frequency hopping interval, and the second value of each bit indicates that the user equipment sets the frequency hopping interval of the application to zero.

13. A method in a network control unit, the method comprising: configuring physical random access channel parameters for user equipment, and configuring frequency hopping parameters for the user equipment, The frequency hopping parameters include at least one configured frequency hopping interval to be used by the user equipment for determining an applied frequency hopping interval.

14. The method according to claim 13, wherein the physical random access channel parameters include: Information about at least one starting random access opportunity.

15. The method according to claim 13 or 14, wherein the frequency hopping parameters include: Number of physical random access channel repetitions.

16. The method according to any one of claims 13 to 15, wherein the frequency hopping parameters include: a configured frequency hopping interval, and further frequency hopping information, the further frequency hopping information comprising a value indicating that the user equipment sets the applied frequency hopping interval to the configured frequency hopping interval or to the inverse of the configured frequency hopping interval, or The frequency hopping interval includes: a configured frequency hopping interval and another configuration information, wherein the another configuration information includes a value indicating that the user equipment sets the applied frequency hopping interval to the configured frequency hopping interval or to zero.

17. A device comprising: at least one processor and at least one memory, the at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to at least: At the user equipment, receiving configuration of physical random access channel parameters and frequency hopping parameters from a network control unit; selecting, based on the configuration, a starting random access opportunity for transmission of a plurality of physical random access channels; Determining an applied frequency hopping interval based on the configuration and the selected starting random access opportunity; as well as The plurality of physical random access channel transmissions are sent from the selected starting random access opportunity based on the determined applied frequency hopping interval.

18. A device comprising: at least one processor and at least one memory, the at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to at least: configuring physical random access channel parameters for user equipment, and configuring frequency hopping parameters for the user equipment, The frequency hopping parameters include at least one configured frequency hopping interval to be used by the user equipment for determining an applied frequency hopping interval.

19. A computer program product comprising: Means for performing the method according to any one of claims 1 to 16 when run on a processing component or module.

20. The computer program product according to claim 19, wherein the computer program product is embodied on a computer-readable medium and / or the computer program product is directly loadable to an internal storage of the computer and / or transmittable via a network by at least one of an upload process, a download process and a push process.

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