CN116963305A

CN116963305A - Method and user equipment for PRACH for coverage enhancement

Info

Publication number: CN116963305A
Application number: CN202310387814.4A
Authority: CN
Inventors: 裵正铉; 穆罕默德·阿瓦丁; 穆罕默德·卡摩斯
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2022-04-26
Filing date: 2023-04-11
Publication date: 2023-10-27

Abstract

A method and User Equipment (UE) for PRACH for coverage enhancement are disclosed. In some embodiments, the method comprises: transmitting, by the UE, a first Physical Random Access Channel (PRACH) transmission in a first random access channel occasion (RO); and transmitting, by the UE, a second PRACH transmission in a second RO, wherein the second PRACH transmission is a repetition of the first PRACH transmission, the second RO having an index that differs from an index of the first RO by a set integer.

Description

Method and user equipment for PRACH for coverage enhancement

The present application claims the priority benefits of U.S. provisional application No. 63/335,116, filed on month 4 of 2022, and U.S. provisional application No. 63/434,881, filed on month 12 of 2022, 22, and U.S. non-provisional application No. 18/168,540, filed on month 13 of 2023, the disclosures of all applications being incorporated by reference as if fully set forth herein.

Technical Field

The present disclosure relates generally to wireless communications. More particularly, the subject matter disclosed herein relates to improvements in the handling of Physical Random Access Channel (PRACH) transmissions in wireless networks with coverage enhancement.

Background

In wireless communication systems, such as mobile telephone systems, the coverage of the wireless network may be a factor limiting the overall performance of the system.

To address this problem, various methods may be used to achieve reliable communications under low signal-to-noise conditions. For example, certain transmissions generated by a user equipment, such as Physical Random Access Channel (PRACH) transmissions, may be repeated. One problem with the above approach is that various parameters (such as preambles) may need to be selected for each repeated transmission.

Disclosure of Invention

To overcome these problems, systems and methods for selecting parameters to be used in each PRACH repetition are described herein. The above approaches improve on previous approaches because they may reduce decoding complexity for the network node (gNB), for example.

According to an embodiment of the present disclosure, there is provided a method comprising: transmitting, by a User Equipment (UE), a first Physical Random Access Channel (PRACH) transmission in a first random access channel occasion (RO); and transmitting, by the UE, a second PRACH transmission in a second RO, the second PRACH transmission being a repetition of the first PRACH transmission, the second RO having an index differing from an index of the first RO by a set integer.

In some embodiments, the first RO is associated with a first Synchronization Signal Block (SSB) index and the second RO is associated with the first SSB index.

In some embodiments, the first PRACH transmission uses a first Uplink (UL) beam and the second PRACH transmission uses a second UL beam different from the first UL beam.

In some embodiments, the set integer is configured by Radio Resource Control (RRC).

In some embodiments, the set integer is configured by a system information block.

In some embodiments, the set integer is configured at UE start-up.

In some embodiments, the first PRACH transmission includes a first preamble having a first preamble index; and the second PRACH transmission includes a second preamble, wherein the second preamble has a second preamble index that differs from the first preamble index by another set integer.

In some embodiments, the method includes transmitting, by the UE, L PRACH transmissions, wherein the L PRACH transmissions include: a first PRACH transmission; and L-1 PRACH repetitions comprising a second PRACH transmission, wherein the L PRACH transmissions are in one SSB-RO association period, wherein L is a positive integer greater than or equal to 2.

In some embodiments, the first PRACH transmission is performed on one of N ' ROs, where N ' ROs are a set proper subset of N available ROs, where N is a positive integer greater than or equal to 2, and N ' is a positive integer less than N.

In some embodiments, the proper subset of settings is configured by Radio Resource Control (RRC).

In some embodiments, the method includes transmitting, by the UE, L PRACH transmissions, wherein the L PRACH transmissions include: a first PRACH transmission; and L-1 PRACH repetitions comprising a second PRACH transmission, wherein the N' ROs are selected based on a value of L, wherein L is a positive integer greater than or equal to 2.

According to an embodiment of the present disclosure, there is provided a method comprising: transmitting, by a User Equipment (UE), a first Physical Random Access Channel (PRACH) transmission including a first preamble in a first RO; and transmitting, by the UE, a second PRACH transmission comprising a second preamble in a second RO, wherein the second PRACH transmission is a repetition of the first PRACH transmission, the first preamble is based on the first root sequence and is cyclically shifted by a first integer, and the second preamble is based on the first root sequence and is cyclically shifted by a second integer, wherein the second integer differs from the first integer by a set integer.

According to an embodiment of the present disclosure, there is provided a User Equipment (UE) including: one or more processors; and a memory storing instructions, wherein the instructions, when executed by the one or more processors, cause the following to be performed: transmitting a first Physical Random Access Channel (PRACH) transmission in a first random access channel occasion (RO); and transmitting a second PRACH transmission in a second RO, wherein the second PRACH transmission is a repetition of the first PRACH transmission, the second RO having an index that differs from the index of the first RO by a set integer.

Drawings

In the following sections, various aspects of the subject matter disclosed herein will be described with reference to exemplary embodiments shown in the drawings, in which:

fig. 1 is an illustration of a 4-step Random Access Channel (RACH) procedure in accordance with an embodiment of the present disclosure;

fig. 2A is an illustration of beams used in PRACH aggregate transmissions according to an embodiment of the disclosure;

fig. 2B is an illustration of beams used in PRACH aggregate transmissions according to an embodiment of the disclosure;

fig. 2C is an illustration of beams used in PRACH aggregate transmissions according to an embodiment of the disclosure;

fig. 3A is an illustration of a first example of Uplink (UL) transmission in accordance with an embodiment of the present disclosure;

fig. 3B is an illustration of a second example of Uplink (UL) transmission according to an embodiment of the disclosure;

Fig. 3C is an illustration of an example of the behavior of Rel-16UE and Rel-17 UE with 3-level PRACH aggregation, according to an embodiment of the disclosure;

fig. 4A illustrates a first order of indexing loops by relative Random Access Channel (RACH) occasion (RO) and Synchronization Signal Block (SSB) indexes according to an embodiment of the present disclosure;

FIG. 4B illustrates a second order through a relative RO index and SSB index loop in accordance with an embodiment of the present disclosure;

FIG. 4C illustrates a number of assumptions that a gNB may make in accordance with an embodiment of the present disclosure;

fig. 4D is an illustration of a determination of PRACH aggregation level according to an embodiment of the disclosure;

fig. 5A is an illustration of PRACH aggregation in accordance with an embodiment of the present disclosure;

fig. 5B is an illustration of PRACH aggregation in accordance with an embodiment of the present disclosure;

fig. 6A is an illustration of PRACH aggregation in accordance with an embodiment of the present disclosure;

fig. 6B is an illustration of PRACH aggregation in accordance with an embodiment of the present disclosure;

fig. 6C is an illustration of PRACH aggregation in accordance with an embodiment of the present disclosure;

fig. 6D is an illustration of PRACH aggregation in accordance with an embodiment of the present disclosure;

fig. 7A is an illustration of a first example of beam selection by a UE and by a gNB in accordance with an embodiment of the disclosure;

fig. 7B is an illustration of a second example of beam selection by a UE and by a gNB in accordance with embodiments of the disclosure;

Fig. 7C is an illustration of a first example of beam selection by a UE in accordance with an embodiment of the present disclosure;

fig. 7D is an illustration of a second example of beam selection by a UE in accordance with an embodiment of the present disclosure;

fig. 8A is a diagram of a portion of a wireless system, in accordance with some embodiments;

FIG. 8B is a flow chart of a method according to some embodiments; and

fig. 9 is a block diagram of an electronic device in a network environment according to an embodiment.

Detailed Description

In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be understood by those skilled in the art that the disclosed aspects may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to obscure the subject matter disclosed herein.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment disclosed herein. Thus, the appearances of the phrase "in one embodiment" or "in an embodiment" or "according to one embodiment" (or other phrases having similar meanings) in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In this regard, as used herein, the word "exemplary" means "serving as an example, instance, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Similarly, hyphenated english terms may occasionally be used interchangeably with corresponding non-hyphenated versions, and uppercase english entries may be used interchangeably with corresponding non-uppercase versions. Such occasional interchangeable uses should not be considered inconsistent with each other.

Furthermore, depending on the context discussed herein, singular terms may include the corresponding plural forms and plural terms may include the corresponding singular forms. It should also be noted that the various figures (including component figures) shown and discussed herein are for illustrative purposes only and are not drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals have been repeated among the figures to indicate corresponding and/or analogous elements.

The terminology used herein is for the purpose of describing some example embodiments only and is not intended to be limiting of the claimed subject matter. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It will be understood that when an element or layer is referred to as being "on," "connected to," or "coupled to" another element or layer, it can be directly on, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly connected to," or "directly coupled to" another element or layer, there are no intervening elements or layers present. Like reference numerals refer to like elements throughout. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. As used herein, the term "or" should be interpreted as "and/or" such that, for example, "a or B" means "a" or "B" or any one of "a and B".

As used herein, the terms "first," "second," and the like are used as labels for nouns following them, and do not imply any order of type (e.g., spatial, temporal, logical, etc.) unless clearly defined to the contrary. Furthermore, the same reference numbers may be used across two or more drawings to refer to parts, components, blocks, circuits, units, or modules having the same or similar functionality. However, such use is merely for simplicity of illustration and ease of discussion; it is not intended that the construction or architectural details of such components or units be the same in all embodiments or that such commonly referenced parts/modules be the only way to implement some example embodiments disclosed herein.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this subject matter belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

As used herein, the term "module" refers to any combination of software, firmware, and/or hardware configured to provide the functionality described herein in connection with the module. For example, software may be embodied as a software package, code, and/or instruction set or instructions, and the term "hardware" as used in any of the embodiments described herein may include, for example, components, hardwired circuitry, programmable circuitry, state machine circuitry, and/or firmware that stores instructions executed by the programmable circuitry, either alone or in any combination. Modules may be collectively or individually embodied as circuitry forming part of a larger system, such as, but not limited to, an Integrated Circuit (IC), a system-on-a-chip (SoC), a component, and the like.

The word "set" when used as an adjective means available to both the UE and the gNB when it is used. For example, the shift value P mentioned in the following Rule (Rule) P1 may be a set integer.

The present disclosure describes a procedure for Physical Random Access Channel (PRACH) enhancements in Coverage Enhancement (CE) scenarios. In the New Radio (NR) fifth generation mobile phone (5G) standard promulgated by the third generation partnership project (3 GPP), UEs are designed to send different Uplink (UL) signals to a base station (gNB). In NR, the UE uses UL transmission to transmit various information to the gNB. Specifically, the UE transmits user data to the gNB in a specific configuration of time and frequency resources called Physical Uplink Shared Channel (PUSCH). In particular, a Medium Access Control (MAC) layer provides user data intended to be delivered to the corresponding layer at the gNB side. The Physical (PHY) layer of the UE takes the MAC layer data as input, and outputs a corresponding PUSCH signal through a PUSCH processing chain. Similarly, the UE transmits control data to the gNB in a channel called a Physical Uplink Control Channel (PUCCH). The control data is referred to as Uplink Control Information (UCI) and is considered as a payload of the PUCCH signal.

In contrast, the UE is designed to receive different Downlink (DL) signals from the base station (gNB). Similar to UL, the UE receives DL transmissions to retrieve various information from the gNB. The UE receives user data from the gNB in a specific configuration of time and frequency resources called Physical Downlink Shared Channel (PDSCH). The PHY layer of the UE extracts data from the physical signal received on the PDSCH and provides the data to the MAC layer. Similarly, the UE receives control data from the gNB in a Physical Downlink Control Channel (PDCCH). The control data is referred to as Downlink Control Information (DCI) and is considered as a payload of the PDCCH.

The UE is provided with a Search Space (SS) set configuration and a control resource set (core) configuration for monitoring DCI in a PDCCH in a serving cell. Specifically, the SS set configuration provides PDCCH monitoring occasion information in the time domain, and each monitoring occasion is associated with a CORESET configuration linked to the SS set configuration. The CORESET configuration provides a set of Resource Blocks (RBs) and symbol durations for PDCCH candidate monitoring, where the PDCCH candidates consist of a set of Control Channel Elements (CCEs) that depend on an aggregation level. The CCE consists of 6 resource element groups, and each REG is a set of 12 consecutive Resource Elements (REs). In other words, the UE will monitor the set of REs for PDCCH candidates located in the specified time and frequency domains based on the CORESET and search space set configuration.

Another physical signal transmitted by the UE is called a Physical Random Access Channel (PRACH). Similar to Long Term Evolution (LTE) cellular systems, the communication between the UE and the gNB is frame-based. During initial access, UE UL transmissions are not time aligned with the gNB frame timing due to unaccounted round trip delay times. To synchronize the frame timing of both the UE and the gNB (or UL and DL), the UE transmits a PRACH signal that is used by the gNB to estimate the round trip delay time. The UE is then informed of the value of the Timing Adjustment (TA), which the UE needs to apply to its UL transmissions to properly align the frame timing. Thus, in the initial access procedure, the UE transmits a PRACH signal in addition to obtaining system information from the gNB, as described below.

Similar to LTE, the UE performs initial access through a process of Random Access (RA). NR Rel-16 supports the 4-step RACH procedure described herein and shown in FIG. 1. Prior to initializing the random access procedure, the UE receives broadcasted system information (master information block (MIB) and System Information Block (SIB)) from the gNB through a Synchronization Signal Block (SSB) transmission. That is, the UE attempts to receive broadcast information, wherein the broadcast information provides the UE with necessary information about retrieving MIB and SIB. The system information informs the UE of the configuration of the random access procedure. Multiple SSBs are typically broadcast in a periodic manner, with each SSB being transmitted by the gNB using a different wide transmission beam. The UE then attempts to decode the various SSBs and selects the best SSB as the SSB with the highest Reference Signal Received Power (RSRP). The SSB indicates the best wide beam used by the gNB to communicate with the UE.

The 4-step RACH procedure is as follows. The UE starts by sending a preamble to the gNB. This is referred to as sending msg1 to the gNB. The UE selects one preamble from a pool of possible preambles. The ID of the preamble selected by the UE is called RAPID. At this point, multiple UEs may potentially initiate a 4-step RA procedure simultaneously. Each UE may use a preamble with a different RAPID. If the preamble reception by the gNB is successful, the gNB sends msg2 to the UE. msg2 contains the RAPID of the preamble selected by one (or, in case of contention, multiple) UEs, the TA value for the UE with the corresponding RAPID, and the UL grant for transmitting msg3.

The UE continues by transmitting msg3 using the resources indicated in the UL grant. msg3 contains a Contention Resolution ID (CRID) of a physical layer provided to the UE by a higher layer. The UE applies the value of TA indicated in msg2 to the transmission of msg3. If multiple UEs have the same RAPID in step 1, these UEs may send msg3 containing different CRIDs. The gNB then transmits msg4 containing the CRID of one UE. The UE with the corresponding CRID continues by sending an Acknowledgement (ACK) message acknowledging successful receipt of msg4 and initial access procedure. Hereinafter, these steps are described in more detail.

The first step is transmission of msg1 (PRACH transmission). The UE initiates a 4-step RACH procedure by sending msg1. During initial access, the UE initiates a contention-based RA (CBRA) RACH procedure. The UE starts by choosing a preamble from a pool of possible preambles. A pool of preambles is determined based on the selected SSBs, and the UE randomly selects among the preambles in the pool. Depending on the selected SSB, the UE also determines a set of time and frequency resources to use when transmitting the selected preamble, wherein the set of time and frequency resources to use is referred to as a PRACH occasion (RO). Since a valid TA is not necessarily available, the preamble is transmitted without timing adjustment. The standard specifies a switching time gap between DL transmissions and subsequent UL PRACH transmissions.

The second step is the transmission of msg2 (random access response (RAR)). The gNB detects all transmitted preambles and thus determines the TA value associated with each transmitted TA. Assuming that each transmitted preamble is exactly selected by one UE, the gNB transmits a response to each UE, wherein the response includes the RAPID of the intended UE; this response is called Random Access Response (RAR). The gNB transmission msg2 may include RARs to one or more UEs. If the UE has a RAR in msg2, then msg2 will also include: 1) The TA value, which should be applied by further transmission by the UE; and 2) UL grants to the UE indicating time/frequency resources to be used by the UE to transmit msg3.

After sending msg1, the UE does not know whether it will receive RAR, nor does it know the exact schedule for msg 2. Instead, it monitors the Type 1PDCCH Common Search Space (CSS) (Type 1-PDCCH-Common Search Space) configured to transmit msg2 for a specific duration. The monitoring period is referred to as the RAR window. During the RAR window, the UE attempts to decode DCI format 1_0, where DCI format 1_0 will schedule the transmission of msg 2.

The third step is the transmission of msg3 (contention resolution). Upon receiving msg2, the UE that detected its RAPID sends msg3 according to the UL grant delivered to the UE in msg 2. msg3 contains a Contention Resolution ID (CRID), which is a 39 bit random number generated by the UE (if not configured). The transmission of msg3 occurs after the TA is applied.

The fourth step is the transmission of msg4 (contention resolution 2). After being able to receive msg3 from multiple UEs in contention, the gNB sends msg4 with CRID for one UE. All UEs transmitting msg3 will attempt to decode the scheduled msg4. A UE that detects its CRID may consider its RACH procedure to be successful and may send an ACK.

When choosing the preamble for msg1 transmission, the UE first determines a group from the combined set of preamble groups from which the UE chooses a particular preamble. The aggregate set of groups is a non-intersecting pool of preambles configured by the gNBs within the cell. When the UE picks a preamble from a particular group, the gNB determines which group the UE picked when it received the preamble. The indication method is inherited in Release 16 (Release-16) 4-step RACH to indicate information about the path loss class between UE and gNB and the potential payload size of msg 3. That is, in release 16 4-step RACH, the gNB configures two sets of preambles (set a and set B). If configured, then (i) if the path loss between the UE and the gNB exceeds a configured threshold, and if the expected payload size of msg3 exceeds a certain threshold, then the UE picks group B, and (ii) otherwise, the UE picks group a.

After the UE sends msg1 and msg3, the UE starts monitoring for the expected replies from the gNB. Specifically, once the last symbol of msg1 (or msg 3) is transmitted, the UE starts a monitoring timer (referred to as a monitoring window) at the next first symbol of CORESET where msg3 (or msg 4) scheduling DCI is expected to be received. The monitoring window duration is a Radio Resource Control (RRC) configured at the UE. If retransmission is required, the UE receives DCI 0_0 during a window in which retransmission of msg3 is scheduled. The monitoring window is restarted after each retransmission.

In the coverage enhanced CE scenario, the PRACH signal is an UL signal that is degraded in decoding performance due to a low SNR. PRACH repetition may be a viable solution in order to enhance its performance. However, it is a challenge to introduce an operating PRACH repetition mechanism in Rel-17 that is efficient and backward compatible with Rel-16.

As used herein, "Rel-17 UE" is as a UE capable of performing one or more features described herein and not specified in release 16 of the 5G standard. The term is not intended to limit the applicability of the features of the present disclosure to any particular version of the 5G (NR) standard or specification.

In some embodiments, PRACH signal transmission may be performed with aggregation in a manner similar in some respects to repeated transmission of PUSCH. The first set of embodiments may be referred to as scheme 1. The scheme involves PRACH signal transmission with aggregation, e.g., rel-17 UE may send multiple PRACH signals in a sequence of Random Access Channel (RACH) occasions (ROs) without initiating a Random Access Response (RAR) response monitoring window after each transmission. This is in contrast to Rel-16 PRACH signal repetition, in which the UE initiates a RAR response monitoring window after each PRACH transmission and sends a retransmission only if the window expires without receiving the corresponding RAR message. For example, as described below for the first and second embodiments, the UE may utilize PRACH signal transmission with aggregation in different ways.

In a first embodiment, the UE may transmit each of the PRACH transmissions using the same uplink transmit (UL-Tx) beam. This may allow the gNB to improve the received signal-to-interference-and-noise ratio (SINR) of the received PRACH signal. Optionally, the gNB may also perform uplink receive (UL-Rx) beam-refined formation using these aggregated PRACH transmissions, where the gNB attempts to receive each of the PRACH aggregated transmissions using a different receive (Rx) beam. The set of Rx beams used by the gNB may be a set of narrow beams that collectively cover the range of the wide Rx beams that were originally used. Upon receiving the PRACH aggregate transmission using the different beams, the gNB determines the best beam.

In a second embodiment, the UE may attempt to perform UL-Tx beam refinement to transmit each of the aggregated PRACH transmissions using a different UL-Tx beam. The gNB may then indicate to the UE which UL-Tx beam is best. The set of Tx beams used by the UE may be a set of narrow beams that collectively cover the range of the wide Tx beams that were originally used. The UE may then be provided with information that helps the UE determine which Tx beam is best received by the gNB. These embodiments are shown in fig. 2A-2C, where fig. 2A shows the use of a constant beam, fig. 2B shows the use of a different transmit beam, and fig. 2C shows the use of a different receive beam.

In both embodiments, one UL-Rx beam refinement may be performed within the preamble repetitions by the gNB using one PRACH signal transmitted, wherein the one PRACH signal consists of preamble repetitions. This is a mechanism that may be employed by the gNB using Rel-16 PRACH transmissions, and may still be employed on top of (i.e., in combination with) the PRACH aggregate transmissions described herein.

In another mechanism, a UE performing PRACH transmission with aggregation may transmit some repetitions using the same UL beam while transmitting other repetitions using a different UL beam. That is, in the set of L aggregations, the UE may transmit n+.l repetitions using the same UL beam, and then change the UL beam over a different set of N repetitions that do not overlap. Each set of N repetitions may be consecutive, or alternatively, the N sets of repetitions may be interleaved. Fig. 3A and 3B show examples of l=6 and n=2, fig. 3A shows a non-interleaved set, and fig. 3B shows an interleaved set.

In Rel-16 PRACH signal repetition, the UE applies a power ramping action, wherein the power ramping action increases the transmission power associated with each PRACH transmission. A Rel-17 PRACH transmission with aggregation may have similar power ramp-up behavior as in Rel-16. The power ramp-up behavior may be configured with the same or different power ramp-up parameters. In other embodiments, a Rel-17 PRACH transmission with aggregation may choose to use the same transmission power in all PRACH signals.

In one set of embodiments, which may be referred to as scheme 2, the RACH mechanism for Rel-17 UE with CE capability (capability) is performed in the same resource with Rel-16 UE. That is, the Rel-17RACH procedure allows the UE to transmit PRACH signals with aggregation in the same resources (i.e., the same ROs and preambles) indicated for the Rel-16 RACH procedure. This approach may be beneficial in terms of resource utilization because no separate set of PRACH resources is required.

With this scheme, rel-16 UE follows the conventional RACH procedure by: the preamble and RO resources corresponding to the Synchronization Signal Block (SSB) index received at the highest Reference Signal Received Power (RSRP) are picked up and PRACH transmission (of Msg 1) is performed in the RO. After the PRACH transmission, the UE starts a RAR response monitoring window, wherein the RAR response monitoring window starts at a first control resource set (CORESET) symbol after the PRACH transmission. The UE does not take PRACH retransmissions unless the RAR window expires and the corresponding RAR is not received. Meanwhile, rel-17 UE uses the same RO and preamble determination scheme as in the conventional RACH procedure. However, rel-17 UE transmits PRACH signal repetition in a later RO associated with the same SSB; the UE does not need to start the RAR window until it sends the last configured retransmission. Rel-16 and Rel-17 UE behavior in this scheme is shown in FIG. 3C. Rel-17 UE has the option to start the RAR window after any of the PRACH transmissions in the PRACH aggregation. This may facilitate early termination of the RACH procedure and UL-Tx beam refinement procedure, as described below.

When Rel-17 UE determines the sequence of the PRACH sequence for transmission, the UE may follow a specific procedure for selecting a preamble from the available set of ROs. One mechanism is for a UE targeting the transmission of L PRACH repetitions to select a preamble from ROs associated with the selected SSB index. More generally, the UE may select a preamble from various ROs according to a specific selection procedure. The process may select the preamble from ROs or other ROs associated with the same SSB index. The procedure may also be deterministic (i.e., a set of certainty that a UE desiring to perform L PRACH transmissions selects L preambles) or random (i.e., a UE desiring to perform L PRACH transmissions may have randomness in the selection of L preambles).

The following nomenclature is used to provide a general description of the preamble selection process. The ith preamble of the set of L preambles may be defined by r _i And p _i Marked, wherein r _i Is a tag carrying the RO for PRACH transmission, and p _i Is a tag of a preamble sequence used in a pool of available preamble sequences in the RO. Similar to conventional operation, the following may be the case: the UE determines a set of L preambles based on an SSB index labeled s, wherein the SSB index labeled s is determined by the UE during an SSB detection phase preceding the PRACH transmission phase. For example, SSB index s may be selected as the SSB index having the highest detected RSRP value.

The set of PRACH resources provided by the PRACH configuration parameters includes a set of ROs, wherein each RO is associated with a particular SSB index. Therefore, the RO tag r= (r ^s ,r ^t ) Can consist of two indexes: SSB index r associated with RO ^s And a relative RO index r associated with the SSB index among the set of RO' s ^t . For example, if there are 4 ROs associated with SSB index s, they will have labels (s, 1), (s, 2), (s, 3), (s, 4). Conversely, if, for example, there are 4 SSB indices available, the set of ttro associated with each of these SSB indices is (1, t), (2, t), (3, t), (4, t). The time resource configuration and the frequency resource configuration of the RO may result in different arrangements of the RO. For example, in ordering ROs in a frequency-first manner, one may begin by first cycling through the rt index (graph4A) Or first pass r ^s The index loops (fig. 4B) to arrange ROs. The above arrangement of ROs need not be an explicit configuration of PRACH resources as provided via the RRC configuration of the UE. In fact, these arrangements are most likely to be implicit results of certain PRACH configurations. For example, the arrangement in fig. 4A may be the result of having 4 SSB indices (where there are 4 ROs for each SSB index in one association period), and where the PRACH configuration period consists of 4 sets of Time Division Multiplexed (TDM) ROs, and there are 4 FDM ROs within one set; fig. 4A shows an association period. Differently, fig. 4B shows an arrangement as a result of having 4 SSB indices, wherein there are 1 RO per SSB index in one association period, and wherein one PRACH configuration period consists of 4 Frequency Division Multiplexed (FDM) ROs; fig. 4B shows four associated time periods.

The step of selecting the ith preamble from the set of L preambles comprises: selecting a tag r for an RO for transmitting an ith preamble _i And a preamble index p used in the RO _i . May be present for selecting r _i (wherein i ε {1, …, L }) for example, five rules herein referred to as R1 through R5.

R1: the UE may select r in any order _i . This corresponds to the selection of L preambles without structure; this may be a simple mechanism, but may not assist the gNB decoding operation.

R2: the UE may choose to causeAnd->R is any effective value _i . This is a more structured version of R1, where all selected ROs are associated with the same SSB index.

R2a: the UE may choose to causeAnd->R of (2) ₁ And select to be +.>And->Residual r for any significant value _i . This forces the UE to initiate a preamble transmission in the first available RO associated with the SSB index; this may have an impact on decoding complexity for the gNB (as discussed in further detail below).

R3: another variation of R2a is to add more structure to R _i (wherein i>1) Is selected from the group consisting of, i.e.,this may provide a high level of structure during the selection process; the value of X may be 1 or other value. When R3 is used, each PRACH transmission in the set of consecutive PRACH transmissions sharing the SSB index may have an RO index that is greater than the RO index of the previous one by a set integer (integer X). X=1 causes the UE to use L consecutive ROs associated with the SSB index. The set integer (X) may be RRC configured, or configured by a system information block, or specified and programmed into the UE in the 5G standard (and configured at UE start-up).

R4: another modification of R3 is not to R _i (wherein i>1) Associated with the same SSB index, i.e.,in this case, other methods can be used for selecting +.>One approach is to select the L nearest ROs, regardless of their SSB index associations; this may help reduce delay in transmitting the preamble.

R5: for selecting r _i (wherein i>1) Another variation of R4 in the method of (a) is to select the L most significantNear ROs, regardless of their SSB index association, while avoiding ROs with specific properties, e.g., FDM ROs, or ROs that have insufficient timelines in between. This may help reduce the burden of UE operation.

May be present for selecting p _i (where i e {1, …, L }) different rules, e.g., two rules referred to herein as P1 and P2.

P1：p _i May be randomly selected from a pool of available preambles in the ith RO-although this lacks any structure in the set of selected preambles, this may be a simple mechanism for describing the operation and thus may make the gNB decoding operation more difficult.

P2：p _i May be determined as a function of the preamble selected in the previous transmission (e.g., p _i ＝p _i-1 +P, where P is some integer value), while randomly selecting P from the first RO ₁ The method comprises the steps of carrying out a first treatment on the surface of the This provides more structure for the set of selected preambles. The integer P may be a set integer, e.g., it may be available (e.g., known) to both the UE and the gNB when the preamble is transmitted. One possibility is to have p=0, in which case the selected preamble is the same for all transmissions.

Some examples of how the procedure for selecting L preambles may be performed are provided below. In the above-described determination rules, there may be a limit to the set of L PRACH transmissions selected, i.e., they must occur within one SSB-RO association period. That is, for N SSBs, all L preambles must be selected within one set of ROs to which N SSBs are fully mapped at least once. This has the benefit of maintaining the traditional nature of the RACH procedure: ensuring that any UE performing RACH operation completes msg1 transmission within the duration of the associated time period will therefore guarantee some level of delay for the RACH procedure and limit UE complexity.

When considering the transmission of Rel-17 UE for L PRACH transmissions, the gNB does not have to know the identity of the UE performing the PRACH transmission and whether this is a legacy UE or Rel-17 UE. Assuming that the largest candidate for the number of repetitions is M, the gNB is also unaware of the exact value l+.m that the UE has selected as the number of PRACH transmissions. Furthermore, in the case where the UE transmits PRACH repetitions using the same beam, the gNB may use these transmissions for joint decoding operations that may increase the decodability of the PRACH transmissions. Thus, the gNB has two options in decoding the PRACH transmission. First, the gNB may process each PRACH transmission independently as if the PRACH transmission originated from a legacy UE. Second, for a given PRACH transmission, the gNB may assume that Rel-17 UE performs the transmission and thus performs joint decoding using the transmission and the corresponding potential L-1 other repetitions.

Option 1 provides a simple decoding operation for a gNB with limited performance, while the second operation may provide better decoding performance at the cost of higher decoding complexity. The main reason behind this complexity is that the gNB must take into account the different assumptions of the potential sequences for the L PRACH transmissions when decoding one PRACH transmission.

For example, the preamble selection operation follows R3 in the case of x=1 (i.e., selects the L nearest ROs associated with the SSB index) and P2 in the case of p=0 (i.e., uses the same preamble index in all ROs). Given the selected SSB index i, there are different assumptions about the UE has generated the preamble when the gNB receives the preamble p in RO r. For example, it may be (i) the UE (e.g., rel-16 UE) performing one PRACH transmission, (ii) the UE performing l=2 PRACH transmissions and the preamble corresponding to the first or second of these transmissions, or (iii) the UE performing l=3 PRACH transmissions (where the current preamble corresponds to the first, second, or third of these transmissions). For L > 3, a similar assumption exists. Fig. 4C shows an example of an assumption made by the gNB when decoding a received PRACH transmission in a configuration in which Rel-17 UE may attempt to have L aggregated PRACH transmissions.

Without constraint, the number of potential hypotheses for a UE that may perform preamble transmission on any given RO is M. The decoding process of the gNB may be severely impacted by the number of potential hypotheses about the situation corresponding to the preamble transmission. In order to evaluate the decoding complexity of the gNB, the following distinction can be made in the implementation of the decoding operation at the gNB end.

Joint decoding method (JD): in this embodiment, the gNB may jointly use the preambles transmitted in all repetitions during the decoding process. In this approach, the gNB may determine or assume which set of preambles belongs to one set of repetitions, such that the decoding operation may be based on the set of preambles.

Repetition decoding method (RD): in this embodiment, the gNB continuously and independently attempts to decode each preamble transmission, thus declaring a preamble transmission successful if any repetition is successfully received. In this approach, the gNB may primarily need to determine or assume whether the preamble transmission is from a legacy UE or from performing repeated Rel-17 UE.

Depending on the implementation, certain measures may be taken to limit the decoding complexity of the gNB. The following are three exemplary restrictions that may be imposed on the preamble that the UE may use, where the UE targets L PRACH repetitions.

In a first limitation, the UE may be limited to transmit a set of L preambles only in a subset of available ROs for legacy preamble transmission. For RD, this limits the number of hypotheses made by the gNB to only one (legacy) RO of ROs that legacy UEs are allowed to use. More specifically, the UE may be instructed to only N 'among the N available ROs'<A set of N ROs (i.e., only a proper subset of the N available ROs) is used to transmit a first preamble of the set of L preambles, and then a subsequent preamble may be transmitted in a consecutive subsequent RO. When (when)And R3 has x=1, the maximum number of hypotheses made by RD gNB is atWill be 2 in RO and in +.>The number of ROs will be 1. The proper subset (i.e., the set of N' ROs) may be a set proper subset, i.e., it may be a proper subset that both the UE and the gNB are available (e.g., known) when the preamble is transmitted. The set of N' ROs may be RRC configured. The set of N' ROs may be uniformly distributed among the N ROs.

In a second limitation, the UE may be instructed to send only a first preamble transmission of the set of L repetitions on a first RO corresponding to the selected SSB index in an association period. With this approach, for JD, the number of hypotheses assumed by the gNB when receiving the preamble in the RO depends on the relative RO location with associated time period. For example, if the RO is the ith RO mapped to the target SSB index for the association period, the number of potential hypotheses for the UE that can perform the preamble transmission is M-i+1. This means that the first RO in the association period may require that the gNB make L hypotheses, while the gNB makes only 1 hypothesis for the last RO.

In a third limitation, the UE may be instructed to transmit a first preamble in a set of L PRACH repetitions in RO positions that depend on the number of repetitions L. For example, assuming that there are N ROs in the association period that correspond to the selected SSB index, one may start at the first RO or the (N/2) th RO in the association periodFirst preamble transmission in a set of one or less repetitions, while starting more than +_ only at the first RO>A first preamble transmission in a repeated set. This provides more flexibility for the UE to start its transmission at the cost of more decoding complexity at the gNB. For JD, the number of hypotheses made by the gNB at each RO may be less than the number of arbitrary starting positions allowed for the L preamble transmissions. A generalization of the third constraint is to provide RO indices for start preamble transmissions corresponding to different values of L at granularity finer than L/2. The above-described limitations may be reused when using the association mode period instead of the association period.

In scheme 2, rel-17 UE only transmits PRACH signals with aggregation if the UE is in a Coverage Enhancement (CE) scenario. That is, the UE makes such a decision based on the received RSRP of the best SSB index it has selected. Such a determination may be made in different ways. For example, in a first embodiment, the UE may have a threshold of γ, and if the RSRP of the received best SSB is less than or equal to γ, the UE may use Rel-17 PRACH signal aggregation; otherwise, it may use the Rel-16 method.

In a second embodiment, the UE may have multiple thresholds γ ₁ ≥γ ₂ ≥γ ₃ ≥...≥γ _N . If the RSRP of the received best SSB is greater than gamma ₁ It uses Rel-16 PRACH transmission. If the RSRP of the received best SSB is greater than gamma ₂ And less than or equal to gamma ₁ It uses Rel-17 PRACH signal aggregation with a certain number of retransmissions. If the RSRP of the received best SSB is greater than gamma ₃ And less than or equal to gamma ₂ It uses Rel-17 PRACH signal aggregation with a larger number of retransmissions and so on. Fig. 4D illustrates this procedure for determining PRACH aggregation level.

Configuring Rel-17 UE with PRACH signal aggregation to perform its transmissions in the same resources as Rel-16 UE may be considered an unfair behavior, e.g., in the sense that such behavior may result in a higher collision rate for Rel-16 UE, which increases the delay in the initial access procedure. However, a refute may be made regarding these issues. For example, if the UE is in a CE scenario, the UE only performs PRACH signal aggregation. In this case, a single PRACH transmission experiences poor channel conditions and is therefore typically received with a low SNR. If the PRACH transmission collides with another PRACH signal from Rel-16 UE, its impact may only be equivalent to a limited interference level and thus the Rel-16 UE initial access procedure may not be significantly hindered. Furthermore, rel-17 UE in the CE case may be considered a UE in a natural adverse situation because its PRACH transmission may be lost or not decoded. Thus, the use of PRACH signal aggregation may be considered a mechanism by which Rel-17 UE may compensate for drawbacks (e.g., poor SNR).

In this setting, the gNB receives PRACH signals without being able to associate these signals with either (i) Rel-16 UE having a single PRACH transmission or (ii) Rel-17 UEs performing a transmission with an aggregated PRACH. In other words, from the perspective of the gNB, one Rel-17UE performing PRACH transmission with, for example, 5-level (5-level) aggregation may be considered as 5 virtual Rel-16 UE. This situation can lead to such a misconfiguration of Rel-17UE if not handled properly: rel-17UE may receive various RAR messages each having a different configuration and TC-RNTI.

One way to handle this situation may be to configure Rel-17UE, which performs PRACH transmission with aggregation, to respond to at most one RAR message corresponding to the preamble ID of the PRACH transmission of Rel-17 UE. This causes the gNB to automatically correct the problem of handling multiple virtual UEs upon receipt of at most one Msg3 corresponding to at most one virtual UE in the set of virtual UEs. As used herein, "preamble ID" refers to a complete identification of the preamble sequence used.

Alternatively, rel-17UE may respond to more than one RAR message corresponding to the preamble IDs of its PRACH transmissions, but indicate in these RAR response messages which preamble IDs are those that are part of its PRACH transmissions. When decoding the RAR response message, the gNB is then made aware of the preamble ID used by the same Rel-17UE, and can then act accordingly.

Fig. 5A and 5B illustrate examples of communication between a gNB and two types of UEs when PRACH transmissions with aggregation are enabled. The Rel-17 UE performing PRACH aggregate transmission may start the RAR window only after the transmission of the last PRACH repetition. The UE may use a different RAR window configuration than the Rel-16 UE configuration for transmitting one PRACH transmission. In this case, the gNB may be aware of the potential PRACH aggregation sequence and send the RAR message in a corresponding RAR window that may be initiated by the potential Rel-17 UE performing the PRACH aggregation. The UE may use the same RAR window configuration as for Rel-16 configuration. In this case, the gNB may correspond to potential Rel-17 UE with the same RAR message as it is for Rel-16 UE.

In this communication, the UE may send a reply to one RAR message, multiple RAR messages, or all RAR messages. The above-described operation of the gNB may be considered wasteful of resources in that, for example, the gNB may respond to receiving multiple PRACH signals from Rel-17 UE, which transmitted PRACH with an aggregation, by transmitting multiple RAR messages. However, due to the expected low SNR of the received PRACH signal, rel-17 UE in the CE case only will perform PRACH transmission with aggregation, and thus such an event is not possible. If the UE does receive multiple RAR messages, the UE may then select the received RAR message with the highest RSRP to respond. As in the second embodiment described above and shown in fig. 2A to 2C, this may be particularly helpful when the UE transmits PRACH signals using a different and narrower beam. An additional benefit of this form of implementing UL beam refinement is at the cost of sending multiple RAR messages. The UE may utilize the transmission of multiple RAR response messages to inform the gNB of information that may be useful for beam refinement operations. For example, the UE may indicate to the gNB the received signal strength associated with each RAR message.

When Rel-17 UE transmits PRACH signals with L-level aggregation, it is necessary to start the RAR response monitoring window at least after transmission of the L-th PRACH signal. However, the UE may also start the RAR response monitoring window at an earlier point in time after transmitting the first PRACH signal. If the UE operates in this manner, the UE may receive a RAR response message corresponding to one of the transmitted PRACH signals before transmitting all L PRACH signals. Assuming that the UE receives the RAR message before transmitting the jth PRACH signal (where "before" means in this context that the time between the received RAR response message and the jth signal is greater than the time required to process the received message and stop transmitting the PRACH signal), the UE may behave as follows.

In a first behavior, referred to as behavior 1 (beahvier-1), the UE may stop transmission of the jth PRACH signal and all subsequent PRACH signals. This may be a viable option if the UE transmits PRACH signals within the PRACH aggregate using the same UL beam. Thus, receipt of the RAR message indicates that the PRACH transmission was successful and no repetition is required.

In a second behavior, referred to as behavior 2 (beahvier-2), the UE may continue to transmit the j-th PRACH signal and all subsequent PRACH signals as if the RAR message had not been received.

In a third behavior, referred to as behavior 3 (beahvier-3), the UE may continue to transmit the j-th PRACH signal and all subsequent PRACH signals. In order to utilize these transmissions, the gNB is required to identify the set of PRACH signals that belong to the PRACH aggregation. Thus, in this option, the UE may report the ID of the upcoming PRACH transmission to the gNB. This can be used in two ways, as described below.

In a first variant of the third behaviour, referred to as behaviour 3a (Behavior-3 a), if an attempt is made to transmit PRACH aggregation using a different UL-Tx beam to identify the best narrow UL beam, continuing such transmission may be for the purpose of UL beam refinement. The gNB may send a message like a RAR after the last PRACH transmission indicating which preamble was best received. The Rel-16 PRACH transmission includes a PRACH format that includes sequence repetition. The gNB may use these repetitions to perform the UL-Rx beam refinement procedure. In this case, act 3a may perform both UL-Tx beam refinement and UL-Rx beam refinement.

In a second variant of the third behaviour, referred to as behaviour 3b (Behavior-3 b), the UE may transmit each PRACH aggregation using the same UL beam. This may yield the option that the gNB may perform the UL-Rx beam refinement procedure: the UE may use the same best UL-Tx beam to transmit the remaining PRACH signals and the gNB may use the UL-Tx beam to search for the best UL-Rx narrow beam.

Fig. 6A to 6D show various possibilities of behaviour of Rel-17 UE for the remaining PRACH signals after receiving a RAR message. When the identification of ROs used in PRACH aggregation is provided to the gNB via a specific Msg3, there may be a number of options. One option is that the identity of each RO may be for the absolute time location and absolute frequency location of the RO. Another option is that the identification may be for a time offset and a frequency offset with respect to the RO associated with the transmitted Msg 3. For example, ROs indicated in PRACH aggregation may be time slot (time division multiplexed (TDM)) ROs before or after a particular RO and time slot (frequency division multiplexed (FDM)) ROs above and below the particular RO. The method may be used to reduce overhead indicating absolute time values and absolute frequency values for a plurality of ROs.

When the UE is in L aggregationsWhen the RAR monitoring window is initiated after the transmission of the PRACH other than the last PRACH transmission, the RAR monitoring window may overlap with a duration including ROs that the UE will transmit subsequent PRACH repetitions. In this case, the UE may not be able to simultaneously monitor the DL RAR message and perform UL PRACH repetition. In this case, certain priority rules (such as the three priority rules described below) may be useful. In a first priority rule, the UE may prioritize PRACH repeated transmissions over monitoring RAR messages. When the UE is expected to preferentially perform transmission of PRACH repetition, a timeline may be established between a time for transmitting a PRACH signal and a time for receiving or monitoring a PDCCH corresponding to the RAR message. That is, it is not desirable that the UE receives a PDCCH corresponding to the RAR message after a time line measured with respect to the transmission of the PRACH repetition. The timeline may be established from the end of the last symbol carrying PRACH repetition or the end of the last symbol for the RO to send the PRACH. The duration of the timeline may be equal to the time required to switch from UL transmission to DL reception: duration T _switch May be equal to the same switching time value defined in the conventional NR specification, or some other value. Because the timeline is established from the beginning of the PRACH transmission, time may also be increased to accommodate the time required to complete the transmission of the PRACH. When the statement "time for receiving/monitoring PDCCH corresponding to RAR message" is mentioned (in the standard), the time may be a) the time of the first symbol carrying PDCCH, or b) the time of the first symbol for CORESET carrying PDCCH.

Additional timelines may be established prior to the PRACH repeated transmission. That is, since PRACH transmission is prioritized over reception of PDCCH corresponding to RAR message, a sufficient time may be reserved before a start time of PRACH transmission to allow UE to switch from DL reception to UL transmission. More specifically, it may be selected from the group consisting of having a duration T _switch The time before the start time of the PRACH transmission (or other value as described above) to the start time of the PRACH transmission. In this timeline, the UE does not expect to receive a PDCCH corresponding to the RAR message. The start time of the PRACH transmission may be the time of the first symbol carrying PRACH repetition, or the first to the RO that will transmit the PRACHThe time of the symbol.

When the gNB attempts to schedule a RAR message corresponding to successful reception of a PRACH transmission, it does not know in advance whether the PRACH transmission was by a legacy UE or by Rel-17 UE performing PRACH repetition. If the UE is Rel-17 UE, the RAR message must be scheduled according to the aforementioned timeline, which is not necessary for legacy UEs. Thus, while the expected UE may be Rel-17 UE performing PRACH repetition, the gNB may take a conservative approach and follow the timeline. Because the gNB may not use portions of the RAR window that do not satisfy the timeline for PRACH repetition occasions, this conservative approach may have an indirect impact on legacy UE operation. Differently, the gNB may take a positive approach and not follow the timeline. Since the UE is not expected to receive the RAR, this behavior is virtually the same as not sending the RAR message for Rel-17 UE. This preserves the potential performance impact of the operation and conventional operation at the cost of not using an earlier RAR transmission to send msg2 to Rel-17 UE.

In the second priority rule, the mechanism for determining ROs for PRACH repetition may establish a set of potential ROs that contains more than one available RO for transmission of one PRACH repetition. For example, one may use a set RO containing more than one RO _i Transmission of the ith PRACH repetition is performed in any RO within. In this case, skipping the use of one or more ROs to support monitoring for RAR messages may not completely skip the possibility that the UE transmits PRACH repetitions. Within the spirit of this observation, the UE may prioritize monitoring RAR messages over transmission of overlapping ROs whenever there is at least one potential RO for transmitting PRACH repetitions. In the third priority rule, the UE may always monitor for RAR messages preferentially.

Depending on the UE behavior, rel-17 UE may be required to send some additional information to the gNB after receiving the RAR message, e.g., the ID of the preamble that the UE has sent and will send during PRACH aggregation may need to be sent to the gNB. This information may be included in the corresponding Msg3. For example, (i) information may be added in the payload of Msg3, or (ii) information may be included in the MAC header of PUSCH corresponding to Msg3. The latter approach may be used to help decode Msg3 if the MAC header is successfully decoded but the PUSCH payload is not. In this case, in the context of message combining, the information extracted from the MAC header may allow the gNB to receive repetitions of Msg3 as described below.

In another mechanism, rel-17 UE may select one preamble among PRACH aggregations to use in the first PRACH transmission, then the UE is restricted to use the same preamble sequence in all upcoming PRACH repetitions. Using this mechanism, the gNB can identify the sequence of the PRACH aggregate transmission once it identifies the preamble sequence used by Rel-17 UE. Since only the RO location is indicated in the Msg3 payload and MAC header, this reduces the overhead of transmitting the preamble ID information of all PRACH transmissions performed by Rel-17 UE. That is, for L-level PRACH aggregation and assuming that there are 64 preambles per RO, L log may be achieved ₂ 64 Reduction of=6l bits.

For each Msg2 (RAR message) scheduled by the gNB, there is a respective resource allocation for PUSCH corresponding to the intended Msg3 (RAR response message) of the UE. A UE with Rel-17 PRACH aggregation needs to respond to at least one Msg2 by sending the corresponding Msg 3. Then, the resource allocation for all remaining hypothetical Msg3 remains to be processed.

One option, known as resource reservation, may be used, as described below. The resource allocation may be reserved in the expected upcoming Msg 3. This is a direct consequence of treating all PRACH transmissions as gNB behaviour from different virtual UEs. Although this incurs waste of resources, it is the simplest behavior. This would be a direct result of UE action 1 and action 2.

Another option, known as resource release, may be used, as described below. Reservation of these resources may be canceled upon determining that the corresponding PRACH transmissions belong to the same UE. This requires that the gNB obtain such information and is therefore a valid option for UE behavior 3. This may be done by letting Rel-17 UE include all preamble IDs sent by the UE in Msg 3. When the gNB receives this Msg3, the gNB knows which other Msg3 reservations correspond to PRACH aggregation and can therefore release their resources.

Another option, known as message combining, may be used, as described below. The UE may be allowed to perform Msg3 repetition or aggregation with additional resources. This also requires informing the gNB that these resource allocations belong to PRACH transmissions within one PRACH aggregation. The same indication mechanism as may be used in the resource release may be used here. The reception of the RAR message response may be enhanced by the gNB using Msg3 repetition. This option is only valid if the gNB is able to retrieve information about the preamble ID in the PRACH aggregation of the UE while still not being able to decode the payload of Msg 3; this may be the case if the UE includes preamble ID information in the MAC header of Msg 2.

Both resource reservation and resource release may require a certain timeline to be feasible. That is, msg2 containing the necessary information must be received far enough before the following Msg3 for the resources to be released or combined. For example, any Msg3 resources that occur after receiving Msg2 but before enough time has elapsed to process Msg2 are automatically processed according to the method of resource reservation. Furthermore, the gNB is informed that any Msg3 transmission of the following must be decoded by the gNB and its information processed by the gNB: (i) UE behavior with respect to PRACH aggregate transmissions (ii) associated Msg3 resources.

The embodiment of fig. 5A may involve the following provisions in the standard. First, if Rel-17 UE passes the CE condition corresponding to the particular aggregation level, the UE is allowed to transmit PRACH signals with L-level aggregation (i.e., a RAR response monitoring window is not employed after each PRACH transmission). Second, rel-17 UE transmission with aggregated PRACH signals may be employed with or without power ramp-up behavior. Third, rel-17 UE responds to at most one corresponding RAR message when transmitting PRACH signals with aggregation. The UE may be configured to reply to the first received RAR message or the UE may be configured to wait for a possible plurality of RAR messages. In the latter case, it may select the RAR message it responds to based on some criteria. An example of such a criterion is the RSRP level of each RAR message. Another example is an indicator added by the gNB in the RAR message, wherein the indicator indicates an RSRP level of the received PRACH signal.

In a set of embodiments, which may be referred to as scheme 3, the RACH mechanism for Rel-17 UE with CE capability may be performed in a separate resource with Rel-16 UE. That is, the Rel-17 RACH procedure allows a UE to transmit PRACH signals with aggregation in different resources than those used for the Rel-16 RACH procedure. The set of separate resources for Rel-17 UE may consist of separate ROs, separate preambles within the same RO, or a combination of both separate ROs and separate preambles within the same RO. With this resource separation, the gNB can determine the presence of Rel-17 UE performing RACH procedure with PRACH aggregation and process the transmission from the UE accordingly.

In this scheme, rel-17 UE follows the conventional RACH procedure by picking the preamble and RO resources corresponding to the SSB index received with the highest RSRP. However, the UE picks such resources among a set of resources configured for the Rel-17 RACH procedure with PRACH aggregation. After transmission, the UE may start the RAR response monitoring window after the last PRACH repetition, start the RAR response monitoring window after each PRACH repetition, or according to other options. In any configuration, the gNB knows the UE behavior from the RAR response monitoring window and acts accordingly.

Although Rel-17 UE may perform PRACH transmissions with L aggregations using dedicated resources, it may still have the possibility to start these L aggregations at any given resource suitable for sending the first PRACH transmission. As discussed above in scheme 2, this may affect the complexity of the decoding operation at the gNB. Thus, the solutions mentioned in the discussion above also apply in this case.

In this scheme, if Rel-17 UE is in CE scenario, the UE only transmits PRACH signals with aggregation. As discussed in scheme 2, the UE uses a threshold or thresholds to make such decisions based on the RSRP of the best SSB index received.

When Rel-17 UE transmits PRACH signals with L-level aggregation, it is necessary to start the RAR response monitoring window at least after transmission of the LPRACH signal. However, the UE may also start the RAR response monitoring window at an earlier point in time after transmitting the first PRACH signal. If the UE operates in this manner, the gNB may provide the UE with a RAR response message corresponding to one of the transmitted PRACH signals before the UE transmits all L PRACH signals. This enables the UE to complete the RACH procedure at an earlier time with reduced latency, but at the cost of higher complexity of monitoring multiple RAR instances. Upon receipt of the RAR message, the UE has the same options (act 1, act 2 and act 3) regarding the transmission of the remaining PRACH signals.

Depending on the UE behavior, rel-17 UE may be required to send some additional information to the gNB after receiving the RAR message, e.g., the IDs of preambles that have been and will be sent by the UE during PRACH aggregation. This information may be included in the corresponding Msg 3. For example, (i) information may be added in the payload of Msg3, or (ii) information may be included in the MAC header of PUSCH corresponding to Msg 3. If the MAC header is successfully decoded but the PUSCH payload is not, this information included in the MAC header may be used to help decode Msg 3. In this case, in the context of message combining, the information extracted from the MAC header may allow the gNB to receive repetitions of Msg3 as described above.

Alternatively, rel-17 UE may bind to the preamble sequence used in PRACH aggregate transmissions. In particular, rel-17 UE may select one preamble among PRACH aggregations for the first PRACH transmission, and then the UE is restricted to using the same preamble sequence in all upcoming PRACH repetitions. Using this mechanism, the gNB can identify the sequence of PRACH aggregate transmissions once it identifies the preamble sequence used by Rel-17 UE. Since the RO configuration for PRACH aggregation transmission is a separate configuration from Rel-16, there is a natural binding behavior in the ROs for PRACH aggregation transmission. Thus, when the preamble sequence is also bundled, this allows the gNB to uniquely determine the sequence of PRACH preambles and ROs in the PRACH aggregation by detecting the first preamble sequence and without any additional information from the UE.

When a UE transmits multiple PRACH, the multiple PRACH may be associated with different SSBs or the same SSB, as described in this disclosure or by using any other method. In this case, it is important to determine which beam should be applied for subsequent transmission or reception of: initial access procedure, msg2, msg3, msg4, and PUCCH carrying hybrid automatic repeat request (HARQ) information for Msg 4.

The beam processing for Msg2 reception may be performed as follows. If the PRACH repetition transmitted is associated with the same SSB, e.g., the PRACH is transmitted at an RO associated with the same SSB, the UE may assume that Msg2 (e.g., msg2-PDCCH or Msg 2-PDSCH) is transmitted using the same beam as that used to transmit the SSB associated with the PRACH repetition. In other words, the UE may assume that the beam for Msg2 (Msg 2-PDCCH or demodulation reference signal (DM-RS) of Msg 2-PDSCH) has the same quasi-co-location (QCL) attribute for SSB and channel state information reference signal (CSI-RS) associated with any of the PRACH repetitions.

If the transmitted PRACH repetition is associated with a different SSB, e.g., the PRACH is transmitted in an RO associated with a different SSB, any of the following methods may be used to assist the UE in determining which beam should be assumed for reception of Msg2 (e.g., msg2-PDCCH or Msg 2-PDSCH).

In order to receive a single RAR after the last PRACH repetition or an earlier PRACH repetition, the properties of the transmission beam for Msg2 (e.g., msg2-PDCCH or Msg 2-PDSCH) may be determined as follows:

the beam for Msg2 (either Msg2-PDCCH or DM-RS of Msg 2-PDSCH) has the same QCL properties for a particular SSB/CSI-RS associated with a particular PRACH repetition determined according to a particular rule, some examples of which are provided below.

It may be assumed that the SSB associated with the last PRACH transmission or the first PRACH transmission is the QCL source Reference Signal (RS) for Msg2. Furthermore, a random access radio network temporary identifier (RA-RNTI) is determined based on the selected PRACH to determine which beam will be used to receive Msg2.

Since PRACH repetition may be associated with different SSBs, each SSB has a different measurement quality, e.g., RSRP. Due to channel reciprocity, the best measured SSB beam at the UE side will correspond to the best measured PRACH at the gNB side. In this case, it is beneficial that this beam (i.e., the beam corresponding to the best measured SSB) can be used for Msg2 transmission to increase the probability of correctly receiving Msg2. This is illustrated in fig. 7A, where SSB2 is determined to be the SSB with the best measurement quality, and the UE assumes that SSB2 is the QCL source RS for Msg2. Furthermore, the RA-RNTI is determined based on the selected PRACH associated with the best measured SSB.

Another possibility is that the UE tries to receive Msg2 in the RAR window using different beams in different parts of the RAR window. As a possibility, assuming that L PRACH repetitions are transmitted, the RAR window is divided into "L" equal parts. In each section, the UE assumes that the beam of Msg2 has the same QCL attribute as one of the SSBs associated with the PRACH repetition. Specifically, for PDCCH monitoring occasions that fall within a particular portion of the RAR window, the UE assumes that the SSB associated with that portion is used as a QCL reference signal for receiving Msg2. As shown in fig. 7B, the beams for Msg2 reception in the RAR window may have the same order as the transmitted PRACH. It is worth mentioning that once the UE successfully receives any RAR response in any earlier part of the RAR window, the UE does not need to monitor every part within the RAR window. In each part, the RA-RNTI is determined based on the selected PRACH. The PRACH repetition transmitted may be ordered based on its transmission position in the time domain, its transmission position in the frequency domain, RACH occasion index, preamble index. For example, the order may be a first one of an increasing order of RACH occasion indexes in the frequency domain, a second one of increasing orders of PRACH occasion indexes in the time domain, etc.

In order to receive multiple RARs that are repeated for each transmitted PRACH associated with a different SSB, conventional methods may be applied to determine the beam properties of Msg2 in each RAR, i.e., to determine that the beam of Msg2 is the source RS of the QCL. However, it may occur that RAR windows associated with different transmitted PRACHs overlap in the time domain. In this case, it is important to define what assumptions should be made about the QCL source RS within the overlapping portion of the RAR window. To deal with this, either of the following two possibilities can be applied.

A first possibility is that the UE does not expect the RAR window to overlap when the RAR window corresponds to different PRACH repetitions associated with different SSBs. However, if PRACH repetition is associated with the same SSB, it may be allowed to have overlapping RARs because the UE does not need to adjust the receive beam based on the beam properties of Msg 2.

A second possibility is that if the RAR windows corresponding to different PRACH repetitions associated with different SSBs overlap, then any of the following procedures may be applied.

In the non-overlapping portion of the RAR, the QCL source RS, i.e. the beam of Msg2, is determined to have the same properties as SSB/CSI-RS associated with PRACH repetition monitoring the RAR in the RAR window, similar to the conventional mechanism.

In the overlapping portion of RARs, the QCL source RS may be based on an earlier starting RAR window. This is illustrated in fig. 7C, where the QCL hypothesis of the earlier-started RAR window covers the QCL hypothesis of the later-started RAR window. Other parameters associated with the earlier starting RAR window may override those of the later RAR, such as RA-RNTI applicable by the UE.

Other rules may be applied to determine the QCL assumption for Msg2 reception and the corresponding RNTI in the overlapping portion of the RAR window. For example, the determination may be based on a measured quality of SSB associated with the RAR window. Revisiting the previous example and assuming that the measured SSB quality (e.g., RSRP) is as follows _SSB1 <RSRP _SSB3 <RSRP _SSB2 That is, SSB2 has the best measurement quality, followed by SSB3, and then SSB1, as shown in fig. 7D, with parameters associated with the RAR window associated with SSB2 (such as QCL hypothesis and RA-RNTI) overriding parameters associated with other RAR windows.

The beam processing for Msg3 transmission may be performed as follows. To ensure that the UE and the gNB have a common understanding of which transmit beam will be used for Msg3 at the UE end and for the Rx beam at the gNB end, the transmit beam of Msg3 may be the same as the PRACH transmit beam associated with the receiving RAR carrying the Msg3 grant. Furthermore, due to channel reciprocity between DL and UL, SSB associated with this PRACH repetition may be used to determine the transmit beam of Msg 3.

To provide more flexibility, the gNB may indicate to the UE which beam should be used when transmitting Msg 3. This solution may be beneficial, for example, when the UE transmits multiple PRACH repetitions associated with different SSBs and the earliest RAR window does not correspond to the best transmit beam at the UE end. In this case, the gNB may indicate the transmission beam of Msg3 using the previously transmitted PRACH repetition or its associated SSB.

For example, a new field in the RAR itself may be used to indicate the beam of Msg 3. The bit width of this field may be equal to the number of PRACH repetitions configured. In this case, this field may indicate the beam of PRACH repetition that may be used to transmit Msg 3. PRACH repetition may be indexed as described in this disclosure or any other method. Alternatively, the gNB may indicate an SSB index that the UE should use to determine the transmission beam of Msg3 in dependence on reciprocity between DL and UL. In this case, the field size may depend on the number of SSBs transmitted.

Furthermore, this field may be located in the Msg2-PDCCH instead of in the RAR itself. In this case, the indicated transmit beam for Msg3 may be applied by all UEs that can find the preamble ID in the scheduled RAR. This field may be similar to the previous field indicating PRACH repetition or SSB that should be used to determine the transmission beam of Msg 3. This is beneficial when the gNB attempts to use a single receive beam for Msg3 in a single Msg2 for all UEs provided by the RAR.

For Msg3 retransmissions scheduled by DCI 0_0 with a Cyclic Redundancy Check (CRC) scrambled by a temporary cell RNTI (TC-RNTI), a field similar to the previous field may be included in DCI 0_0 to indicate which PRACH repetition or associated SSB is to be used to determine the beam of Msg 3. For example, in this DCI, NDI and HARQ fields are reserved and, as described above, they may be reused to indicate which beam should be applied for Msg3 retransmission. Optionally, a new field may be introduced to indicate the beam for Msg 3.

Another option for determining the beam for the Msg3 retransmission is that the same beam indicated by Msg2 (Msg 2-PDCCH or Msg 2-PDSCH) in the initial transmission can still be applied in case of Msg3 retransmission.

The beam processing for Msg4 reception may be performed as follows. If the UE receives a single Msg2, the UE may assume that the same SSB used as the QCL source RS for Msg2 is the SSB that should be assumed to be the QCL source RS for Msg 4. In other words, the DM-RS scheduling the PDCCH of Msg4 has the same QCL attribute as the SSB that the UE uses to receive Msg 2. If there are multiple scheduled msgs 2 of the QCL with different SSBs and each Msg2 provides a different RAR, the UE may select one of these RARs based on the quality of these RARs (e.g., RSRP of Msg2-PDCCH or Msg 2-PDSCH), based on the order of reception in the time domain, etc., to determine the resources of Msg 3. In this case, the UE may assume that the SSB may be a QCL source RS for Msg4, wherein the SSB serves as a QCL source RS for Msg2 that provides authorization for Msg3 to be used.

The configuration process may be performed as follows. In a conventional NR, the gNB may define multiple sets of features including reduced capability (redcap), small data (smallData), msg3 Repetition (msg 3-Repetition), and the like, and may indicate the associated set of preambles and RO. For example, the gNB may configure the following feature sets: s is S ₀ ＝{redcap}、S ₁ ＝{msg3-Repetition}、S ₂ = { redcap, msg3-Repetition } and S ₃ = { smallData, msg3-Repetition }. For each, the gNB may indicate that the set of features (e.g., S ₀ 、S ₁ 、S ₂ Or S ₃ ) The number of consecutive preambles of each SSB and the index of the first preamble are associated to indicate the dedicated preamble. Further, the gNB may indicate that a set of features (e.g., S ₀ 、S ₁ 、S ₂ Or S ₃ ) Is a subset of ROs of (a).

Defining a new feature related to PRACH repetition (RACH-repetition) is a straightforward solution that enables the gNB to combine this feature with other features when needed and indicate the corresponding preamble. That is, the FeatureComposition-r 17 has a plurality of spare values, one of which is available for PRACH repetition. This enables the gNB to define a feature set comprising { PRACH-Repetition, msg3-Repetition } and then use the FeatureCompositionPreamble to configure common preamble resources for both features.

In order to keep the spare value for future use, and to take advantage of the fact that PRACH may also need to be repeated if Msg3 needs to be repeated, the set of preambles associated with PRACH repetition may be the same as the set of preambles that would be used when requesting Msg3 repetition.

Further, in conventional NR, gNB may be configured with a unique priority index for each feature when the feature maps to more than one feature set (e.g., feature msg3-Repetition at S ₀ 、S ₁ 、S ₂ And S is ₃ The unique priority index may be used to determine the set of preambles from which to select. One possibility is to define priorities for PRACH repetition features. Alternatively, the UE may assume that PRACH Repetition has the same priority as indicated to msg3-Repetition to reduce signaling overhead. This is also significant when both msg3-Repetition and PRACH-Repetition occur together. Furthermore, in conventional NR, the UE uses rsrp-ThresholdMsg3 to determine whether to select a resource indicating whether Msg3 repetition is required. This field is mandatory when the set of random access resources is configured for both with repeated Msg3 or without repeated Msg 3. As described in this disclosure, a dedicated RRC parameter (e.g., rsrp-threshhold PRACH) may be configured separately such that the UE may use the dedicated RRC parameter to determine whether PRACH repetition is required. However, if this parameter is not configured, the UE may use rsrp-threshldmsg 3 to decide on the necessity of PRACH repetition in addition to rsrp-threshldmsg 3 to determine if repetition is needed for Msg 3.

Fig. 8A illustrates a portion of a wireless system. User Equipment (UE) 805 sends transmissions to network node (gNB) 810 and receives transmissions from gNB 810. The UE includes a radio 815 and processing circuitry (or "processor") 820. In operation, processing circuit 820 may perform the various methods described herein, e.g., it may receive information from the gNB 810 (via a radio that is part of a transmission received from the gNB 810), and it may send information to the gNB 810 (via a radio that is part of a transmission sent to the gNB 810).

Fig. 8B is a flow chart of a method in some embodiments. The method comprises the following steps: at 830, transmitting, by a User Equipment (UE), a first Physical Random Access Channel (PRACH) transmission using a first preamble in a first random access channel occasion (RO); and at 832, transmitting, by the UE, a second PRACH transmission in a second RO using a second preamble. The second PRACH transmission may be a repetition of the first PRACH transmission, and (i) the second RO may have an index that differs from the index of the first RO by a set integer, or (ii) the first preamble may be based on the first root sequence and be cyclically shifted by the first integer, and the second preamble may be based on the first root sequence and be cyclically shifted by a second integer, wherein the second integer differs from the first integer by the set integer. In some embodiments, the first RO is associated with a first Synchronization Signal Block (SSB) index and the second RO is associated with the first SSB index. In some embodiments, the first RO is associated with a first SSB transmitted on a first downlink beam and the second RO is associated with a second SSB transmitted on a second downlink beam different from the first downlink beam. In some embodiments, the set integer is Radio Resource Control (RRC) configured. In some embodiments, the set integer is configured by a system information block. In some embodiments, the set integer is configured at UE start-up. In some embodiments: the first PRACH transmission includes a first preamble based on a first root sequence and cyclically shifted by a first integer; and the second PRACH transmission includes a second preamble based on the first root sequence and cyclically shifted by a second integer, wherein the second integer differs from the first integer by a set integer. In some embodiments, the first PRACH transmission includes a first preamble, wherein the first preamble has a first preamble index, and the second PRACH transmission includes a second preamble, wherein the second preamble has a second preamble index that differs from the first preamble index by another set integer.

The method may further comprise: at 834, L PRACH transmissions are sent, wherein the L PRACH transmissions include: a first PRACH transmission; and L-1 PRACH retransmissions comprising a second PRACH transmission, wherein the L PRACH transmissions are in one SSB-RO association period. In some embodiments, the L PRACH transmissions are made within a set of N' ROs, which are a set proper subset of the N available ROs. In some embodiments, the proper subset of settings is Radio Resource Control (RRC) configured. In some embodiments, the first RO is selected based on the value of L. In some embodiments, the N' ROs are selected based on the value of L.

Fig. 9 is a block diagram of an electronic device in a network environment 900 according to an embodiment.

Referring to fig. 9, an electronic device 901 in a network environment 900 may communicate with the electronic device 902 via a first network 998 (e.g., a short-range wireless communication network) or with the electronic device 904 or server 908 via a second network 999 (e.g., a long-range wireless communication network). The electronic device 901 may communicate with the electronic device 904 via the server 908. The electronic device 901 may include a processor 920, a memory 930, an input device 950, a sound output device 955, a display device 960, an audio device 970, a sensor module 976, an interface 977, a haptic module 979, a camera module 980, a power management module 988, a battery 989, a communication module 990, a Subscriber Identity Module (SIM) 996, or an antenna module 997. In one embodiment, at least one of the components (e.g., display device 960 or camera module 980) may be omitted from the electronic device 901, or one or more other components may be added to the electronic device 901. Some components may be implemented as a single Integrated Circuit (IC). For example, a sensor module 976 (e.g., a fingerprint sensor, iris sensor, or illuminance sensor) may be embedded in the display device 960 (e.g., a display).

The processor 920 may execute software (e.g., program 940) to control at least one other component (e.g., hardware or software component) of the electronic device 901 in conjunction with the processor 920, and may perform various data processing or calculations.

As at least part of the data processing or calculation, the processor 920 may load commands or data received from another component (e.g., the sensor module 946 or the communication module 990) into the volatile memory 932, process the commands or data stored in the volatile memory 932, and store the resulting data in the non-volatile memory 934. The processor 920 may include a main processor 921 (e.g., a Central Processing Unit (CPU) or an Application Processor (AP)) and a secondary processor 923 (e.g., a Graphics Processor (GPU), an Image Signal Processor (ISP), a sensor hub processor, or a Communication Processor (CP)), and the secondary processor 923 may operate independently of the main processor 921 or in conjunction with the main processor 921. Additionally or alternatively, the auxiliary processor 923 may be adapted to consume less power than the main processor 921, or to perform certain functions. The auxiliary processor 923 may be implemented separately from the main processor 921 or as part of the main processor 921.

The auxiliary processor 923 (instead of the main processor 921) may control at least some of the functions or states associated with at least one of the components of the electronic device 901 (e.g., the display device 960, the sensor module 976, or the communication module 990) when the main processor 921 is in an inactive (e.g., sleep) state, or the auxiliary processor 923 may control at least some of the functions or states associated with at least one of the components of the electronic device 901 (e.g., the display device 960, the sensor module 976, or the communication module 990) with the main processor 921 when the main processor 921 is in an active state (e.g., executing an application). The auxiliary processor 923 (e.g., an image signal processor or a communication processor) may be implemented as part of another component (e.g., a camera module 980 or a communication module 990) that is functionally related to the auxiliary processor 923.

The memory 930 may store various data used by at least one component of the electronic device 901 (e.g., the processor 920 or the sensor module 976). The various data may include, for example, software (e.g., program 940) and input data or output data for commands associated therewith. Memory 930 may include volatile memory 932 or nonvolatile memory 934.

Programs 940 may be stored as software in memory 930 and may include, for example, an Operating System (OS) 942, middleware 944, or applications 946.

The input device 950 may receive commands or data from outside the electronic device 901 (e.g., a user) to be used by another component of the electronic device 901 (e.g., the processor 920). Input device 950 may include, for example, a microphone, a mouse, or a keyboard.

The sound output device 955 may output a sound signal to the outside of the electronic device 901. The sound output device 955 may include, for example, a speaker or a receiver. The speaker may be used for general purposes, such as playing multimedia or recording, and the receiver may be used to receive incoming calls. The receiver may be implemented separate from the speaker or as part of the speaker.

The display device 960 may visually provide information to the outside (e.g., a user) of the electronic device 901. The display device 960 may include, for example, a display, a holographic device, or a projector, and control circuitry for controlling a respective one of the display, holographic device, and projector. The display device 960 may include touch circuitry adapted to detect touches or sensor circuitry (e.g., pressure sensors) adapted to measure the strength of forces caused by touches.

The audio device 970 may convert sound to an electrical signal and vice versa. The audio device 970 may obtain sound via the input device 950 or output sound via the sound output device 955 or headphones of an external electronic device 902 that is directly (e.g., wired) or wirelessly coupled to the electronic device 901.

The sensor module 976 may detect an operational state (e.g., power or temperature) of the electronic device 901 or an environmental state (e.g., a state of a user) external to the electronic device 901, and then generate an electrical signal or data value corresponding to the detected state. The sensor module 976 may include, for example, a gesture sensor, a gyroscope sensor, an atmospheric pressure sensor, a magnetic sensor, an acceleration sensor, a grip sensor, a proximity sensor, a color sensor, an Infrared (IR) sensor, a biometric sensor, a temperature sensor, a humidity sensor, or an illuminance sensor.

The interface 977 may support one or more specified protocols for the electronic device 901 to interface directly (e.g., wired) or wirelessly with the external electronic device 902. Interface 977 may include, for example, a High Definition Multimedia Interface (HDMI), a Universal Serial Bus (USB) interface, a Secure Digital (SD) card interface, or an audio interface.

The connection end 978 may include a connector via which the electronic device 901 may be physically connected with the external electronic device 902. The connection end 978 may include, for example, an HDMI connector, a USB connector, an SD card connector, or an audio connector (e.g., a headphone connector).

The haptic module 979 may convert the electrical signal into mechanical stimulus (e.g., vibration or movement) or electrical stimulus that may be recognized by a user via a tactile or kinesthetic sensation. The haptic module 979 may include, for example, a motor, a piezoelectric element, or an electrostimulator.

The camera module 980 may capture still images or moving images. The camera module 980 may include one or more lenses, image sensors, image signal processors, or flash lamps. The power management module 988 may manage power supplied to the electronic device 901. The power management module 988 may be implemented as at least part of, for example, a Power Management Integrated Circuit (PMIC).

The battery 989 may provide power to at least one component of the electronic device 901. The battery 989 may include, for example, a primary non-rechargeable battery, a rechargeable secondary battery, or a fuel cell.

The communication module 990 may support establishing a direct (e.g., wired) communication channel or a wireless communication channel between the electronic device 901 and an external electronic device (e.g., the electronic device 902, the electronic device 904, or the server 908), and performing communication via the established communication channel. The communication module 990 may include one or more communication processors that are operable independently of the processor 920 (e.g., an AP) and support direct (e.g., wired) or wireless communication. The communication module 990 may include a wireless communication module 992 (e.g., a cellular communication module, a short-range wireless communication module, or a Global Navigation Satellite System (GNSS) communication module) or a wired communication module 994 (e.g., a Local Area Network (LAN) communication module or a Power Line Communication (PLC) module). A respective one of these communication modules may be via a first network 998 (e.g., a short-range communication network such as bluetooth ^TM Wireless fidelity (Wi-Fi) direct or infrared data association (IrDA) standard) or a second network 999 (e.g., a long-range communications network such as a cellular network, the internet, or a computer network (e.g., a LAN or Wide Area Network (WAN)) with an external electronic device. These various types of communication modules may be implemented as a single component (e.g., a single IC), or may be implemented as multiple components (e.g., multiple ICs) separate from one another. The wireless communication module 992 can use subscriber information (e.g., an International Mobile Subscriber Identity (IMSI)) stored in the user identification module 996 to identify and authenticate a communication network, such asA first network 998 or a second network 999).

The antenna module 997 may transmit signals or power to or receive signals or power from outside of the electronic device 901 (e.g., an external electronic device). The antenna module 997 may include one or more antennas, and thus, at least one antenna suitable for a communication scheme used in a communication network, such as the first network 998 or the second network 999, may be selected, for example, by the communication module 990 (e.g., the wireless communication module 992). Signals or power may then be transmitted or received between the communication module 990 and the external electronic device via the selected at least one antenna.

Commands or data may be sent or received between the electronic device 901 and the external electronic device 904 via the server 908 in conjunction with the second network 999. Each of the electronic device 902 and the electronic device 904 may be the same type as the electronic device 901 or a different type of device. All or some of the operations to be performed at the electronic device 901 may be performed at one or more of the external electronic device 902, the external electronic device 904, or the server 908. For example, if the electronic device 901 should automatically perform a function or service or should perform a function or service in response to a request from a user or another device, the electronic device 901 may request the one or more external electronic devices to perform at least part of the function or service instead of or in addition to the function or service. The one or more external electronic devices that received the request may perform the requested at least part of the function or service or perform another function or another service related to the request and transmit the result of the performing to the electronic device 901. The electronic device 901 may provide the results, with or without further processing of the results, as at least a portion of a reply to the request. To this end, for example, cloud computing, distributed computing, or client-server computing techniques may be used.

Embodiments of the subject matter and the operations described in this specification can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. Embodiments of the subject matter described in this specification can be implemented as one or more computer programs (i.e., one or more modules of computer program instructions) encoded on a computer storage medium for execution by, or to control the operation of, data processing apparatus. Alternatively or additionally, the program instructions may be encoded on a manually-generated propagated signal (e.g., a machine-generated electrical, optical, or electromagnetic signal) that is generated to encode information for transmission to suitable receiver apparatus for execution by data processing apparatus. The computer storage medium may be or be included in a computer readable storage device, a computer readable storage substrate, a random or serial access memory array or device, or a combination of computer readable storage devices, computer readable storage substrates, random or serial access memory arrays or devices. Furthermore, while the computer storage medium is not a propagated signal, the computer storage medium may be a source or destination of computer program instructions encoded in an artificially generated propagated signal. Computer storage media may also be or be included in one or more separate physical components or media (e.g., multiple CDs, disks, or other storage devices). Additionally, the operations described in this specification may be implemented as operations performed by a data processing apparatus on data stored on one or more computer readable storage devices or received from other sources.

Although this description may contain many specific implementation details, the implementation details should not be construed as limiting the scope of any claimed subject matter, but rather as descriptions of features specific to particular embodiments. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Furthermore, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Similarly, although operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In some cases, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

Thus, particular embodiments of the subject matter have been described herein. Other embodiments are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results. In addition, the processes depicted in the accompanying drawings do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In some embodiments, multitasking and parallel processing may be advantageous.

As will be recognized by those skilled in the art, the innovative concepts described herein can be modified and varied over a wide range of applications. Accordingly, the scope of the claimed subject matter should not be limited to any of the specific exemplary teachings discussed above, but is instead defined by the appended claims.

Claims

1. A method, comprising:

transmitting, by a user equipment UE, a first physical random access channel PRACH transmission in a first random access channel occasion RO; and

a second PRACH transmission is sent by the UE in a second RO,

wherein the second PRACH transmission is a repetition of the first PRACH transmission, the second RO having an index that differs from an index of the first RO by a set integer.

2. The method of claim 1, wherein the first RO is associated with a first synchronization signal block SSB index and the second RO is associated with the first SSB index.

3. The method of claim 1, wherein the first PRACH transmission uses a first uplink UL beam and the second PRACH transmission uses a second UL beam different from the first UL beam.

4. The method of claim 1, wherein the set integer is configured by a radio resource control, RRC.

5. The method of claim 1, wherein the set integer is configured by a system information block.

6. The method of claim 1, wherein the set integer is configured at a start-up of the UE.

7. The method according to claim 1, wherein:

the first PRACH transmission includes a first preamble, wherein the first preamble has a first preamble index; and

the second PRACH transmission includes a second preamble, wherein the second preamble has a second preamble index that differs from the first preamble index by another set integer.

8. The method according to claim 1, comprising: transmitting, by the UE, L PRACH transmissions, wherein the L PRACH transmissions include:

the first PRACH transmission; and

including L-1 PRACH repetitions of the second PRACH transmission,

wherein the L PRACH transmissions are in one SSB-RO association period, where L is a positive integer greater than or equal to 2.

9. The method of claim 1, wherein the first PRACH transmission is performed on one of N ' ROs, wherein the N ' ROs are a set proper subset of N available ROs, wherein N is a positive integer greater than or equal to 2, and N ' is a positive integer less than N.

10. The method of claim 9, wherein the proper subset of settings is configured by Radio Resource Control (RRC).

11. The method of claim 9, comprising: transmitting, by the UE, L PRACH transmissions, wherein the L PRACH transmissions include:

the first PRACH transmission; and

including L-1 PRACH repetitions of the second PRACH transmission,

wherein the N' ROs are selected based on the value of L,

wherein L is a positive integer greater than or equal to 2.

12. A method, comprising:

transmitting, by the user equipment UE, a first physical random access channel, PRACH, transmission comprising a first preamble in a first RO; and

a second PRACH transmission including a second preamble is sent by the UE in a second RO,

wherein the second PRACH transmission is a repetition of the first PRACH transmission,

the first preamble is based on a first root sequence and is cyclically shifted by a first integer, and

The second preamble is based on the first root sequence and is cyclically shifted by a second integer, wherein the second integer differs from the first integer by a set integer.

13. The method of claim 12, comprising: transmitting, by the UE, L PRACH transmissions, wherein the L PRACH transmissions include:

the first PRACH transmission; and

including L-1 PRACH repetitions of the second PRACH transmission,

wherein the L PRACH transmissions are in one SSB-RO association period,

wherein L is a positive integer greater than or equal to 2.

14. The method of claim 12, wherein the first PRACH transmission is performed on one of N ' ROs, wherein the N ' ROs are a set proper subset of N available ROs, wherein N is a positive integer greater than or equal to 2, and N ' is a positive integer less than N.

15. The method of claim 14, wherein the proper subset of settings is configured by a radio resource control, RRC.

16. The method of claim 14, comprising: transmitting, by the UE, L PRACH transmissions, wherein the L PRACH transmissions include:

the first PRACH transmission; and

including L-1 PRACH repetitions of the second PRACH transmission, wherein the N' ROs are selected based on a value of L,

Wherein L is a positive integer greater than or equal to 2.

17. A user equipment, UE, comprising:

one or more processors; and

a memory storing instructions, wherein the instructions, when executed by the one or more processors, cause performance of the following operations:

transmitting a first physical random access channel PRACH transmission in a first random access channel occasion RO; and

a second PRACH transmission is sent in a second RO,

18. The UE of claim 17, wherein the first RO is associated with a first synchronization signal block SSB index and the second RO is associated with the first SSB index.

19. The UE of claim 17, wherein the first PRACH transmission uses a first uplink UL beam and the second PRACH transmission uses a second UL beam different from the first UL beam.

20. The UE of claim 17, wherein the set integer is configured by a radio resource control, RRC.