Method, device and system for preamble aggregation in random access process

Abstract

Methods, apparatus, and systems for preamble aggregation in a random access process are described. In one embodiment, a method for preamble aggregation performed by a wireless communication device is disclosed. The method includes: transmitting a first message to a wireless communication node, the first message including multiple copies of a preamble for access to the wireless communication node, wherein the number is an integer greater than 1, and wherein the copies of the preamble are respectively carried by different uplink random access channel (RACH) opportunities; and monitoring a second message within a response time window, the second message including a response to the first message from the wireless communication node, wherein all copies of the preamble are transmitted before the response time window expires.

Description

[0001] This application is a divisional application of the Chinese patent application with application number "202080003256.1", application date "September 28, 2020", and title "Method, device and system for preamble code aggregation in random access process". Technical Field

[0002] The present disclosure relates generally to wireless communications, and more particularly, to methods, apparatus, and systems for preamble aggregation in a random access procedure in wireless communications. Background Art

[0003] The fifth generation (5G) new radio (NR) mobile communication will be systematically networked on higher carrier frequencies than those used in 2G, 3G and 4G systems. At present, the industry has widely and internationally recognized frequency bands mainly from 3GHz to 6GHz and 6GHz to 100GHz. Compared with the networking frequencies of early communication systems, these frequency bands are relatively high, with large losses during propagation, and also with a relatively small coverage radius at the same power. In order to keep similar coverage consistent with traditional systems such as 2G, 3G and 4G, the coverage of the 5G new generation mobile communication system should be strengthened, especially for the initial access channel.

[0004] In the traditional four-step Long Term Evolution (LTE) or NR random access procedure, the first step is that the user equipment (UE) sends a physical random access channel (PRACH) signal, such as a preamble or message (Msg) 1. The second step is that the network sends a random access response (in Msg 2) to the UE after receiving the PRACH. The UE then attempts to detect the random access response. If the time window for detecting the random access response expires, or if the UE cannot decode the corresponding random access response, or if the random access preamble identifier in the random access response does not match the preamble index transmitted in the PRACH, then the UE will consider the random access response reception to be unsuccessful and will initiate a retransmission of the PRACH. The PRACH response window length is at least 10ms, which means that the delay caused by retransmission after the response window expires will be very large and cannot be accepted by some delay-sensitive services such as ultra-reliable low latency communication (URLLC) services.

[0005] Both NR systems and NR UEs have multi-beam transmission capabilities. Each beam can focus the radio signal energy to a specific direction and improve coverage and the probability of successful access. It is important for NR systems and UEs to study the best beams for transmission and reception. From the UE's perspective, based on the reciprocity principle, the direction of the best receiving beam on the UE side is likely to be the direction of the UE's best transmitting beam. However, in real scenarios, when the reciprocity on the UE side is less than perfect, sometimes the direction of the UE's best transmitting beam may not be the direction of the UE's best receiving beam. Finding the best transmit beam should be done during the initial access process. Traditional beam switching only occurs in the retransmission of PRACH after the response window expires. Therefore, finding the best transmit beam in the traditional method results in unexpected delays, which is the same as the problem mentioned above about traditional PRACH retransmission. Summary of the invention

[0006] The exemplary embodiments disclosed herein are intended to solve problems related to one or more problems raised in the prior art, as well as to provide additional features that will become readily apparent by reference to the following detailed description when combined with the accompanying drawings. According to various embodiments, exemplary systems, methods, devices, and computer program products are disclosed herein. However, it should be understood that these embodiments are presented by way of example rather than limitation, and it will be apparent to those of ordinary skill in the art who read this disclosure that various modifications may be made to the disclosed embodiments while remaining within the scope of this disclosure.

[0007] In one embodiment, a method for preamble aggregation performed by a wireless communication device is disclosed. The method includes: transmitting a first message to a wireless communication node, the first message including a plurality of copies of a preamble for accessing the wireless communication node, wherein the number of copies is an integer greater than 1, and wherein the copies of the preamble are respectively carried by different uplink random access channel (RACH) opportunities; and monitoring a second message within a response time window, the second message including a response to the first message from the wireless communication node, wherein all copies of the preamble are transmitted before the response time window expires.

[0008] In another embodiment, a method for preamble aggregation performed by a wireless communication node is disclosed. The method includes: receiving a first message from a wireless communication device, which includes multiple copies of a preamble for accessing the wireless communication node, wherein the number of copies is an integer greater than 1, and the copies of the preamble are respectively carried by different uplink random access channel (RACH) opportunities; and transmitting a second message including a response to the first message to the wireless communication device, wherein the second message is monitored by the wireless communication device within a response time window, and before the response time window expires, all copies of the preamble are transmitted by the wireless communication device.

[0009] In various embodiments, a wireless communication node configured to perform the methods disclosed in some embodiments is disclosed. In another embodiment, a wireless communication device configured to perform the methods disclosed in some embodiments is disclosed. In yet another embodiment, a non-transitory computer-readable medium having computer-executable instructions stored thereon for performing the methods disclosed in some embodiments is disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Various exemplary embodiments of the present disclosure are described in detail below with reference to the following drawings. The drawings are provided for illustrative purposes only and depict only exemplary embodiments of the present disclosure to facilitate the reader's understanding of the present disclosure. Therefore, the drawings should not be considered to limit the breadth, scope or applicability of the present disclosure. It should be noted that for clarity and convenience of description, these drawings are not necessarily drawn to scale.

[0011] Figure 1 An exemplary communication network is shown in which the techniques disclosed herein may be implemented according to some embodiments of the present disclosure.

[0012] Figure 2 An exemplary random access procedure according to some embodiments of the present disclosure is shown.

[0013] Figure 3 A block diagram of a base station (BS) according to some embodiments of the present disclosure is shown.

[0014] Figure 4 A flowchart of a method performed by a BS for performing preamble aggregation in a random access procedure according to some embodiments of the present disclosure is shown.

[0015] Figure 5 A block diagram of a user equipment (UE) according to some embodiments of the present disclosure is shown.

[0016] Figure 6 A flowchart of a method performed by a UE for performing preamble aggregation in a random access procedure according to some embodiments of the present disclosure is shown.

[0017] Fig. 7A An exemplary scheme for preamble aggregation according to some embodiments of the present disclosure is shown.

[0018] Figure 7B Another exemplary scheme for preamble aggregation according to some embodiments of the present disclosure is shown.

[0019] Fig. 8A An exemplary hybrid scheme for preamble aggregation according to some embodiments of the present disclosure is shown.

[0020] Figure 8B Another exemplary hybrid scheme for preamble aggregation according to some embodiments of the present disclosure is shown.

[0021] Fig. 9 An exemplary allocation of random access channel (RACH) opportunities for different aggregation levels according to some embodiments of the present disclosure is shown.

[0022] Fig.10 An exemplary resource allocation of distributed RACH opportunities (RO) for preamble aggregation according to some embodiments of the present disclosure is shown.

[0023] Fig.11 Another exemplary resource allocation of distributed RO for preamble aggregation according to some embodiments of the present disclosure is shown.

[0024] Fig.12 Yet another exemplary resource allocation of distributed RO for preamble aggregation according to some embodiments of the present disclosure is shown.

[0025] Fig.13 An exemplary resource allocation of localized RO for preamble aggregation according to some embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0026] Various exemplary embodiments of the present disclosure are described below with reference to the accompanying drawings so that those of ordinary skill in the art can make and use the present disclosure. It is obvious to those of ordinary skill in the art that, after reading the present disclosure, various changes or modifications can be made to the examples described herein without departing from the scope of the present disclosure. Therefore, the present disclosure is not limited to the exemplary embodiments and applications described and shown herein. In addition, the specific order and / or hierarchy of the steps in the methods disclosed herein are merely exemplary methods. Based on design preferences, the specific order or hierarchy of the steps of the disclosed methods or processes can be rearranged while remaining within the scope of the present disclosure. Therefore, it will be understood by those of ordinary skill in the art that the methods and techniques disclosed herein present various steps or actions in a sample order, and unless otherwise expressly stated, the present disclosure is not limited to the specific order or hierarchy presented.

[0027] A typical wireless communication network includes one or more base stations (generally referred to as "BS"), each providing a geographical radio coverage, and one or more wireless user equipment devices (generally referred to as "UE") capable of transmitting and receiving data within the radio coverage. In a wireless communication network, the BS and the UE can communicate with each other via a communication link (e.g., via a downlink radio frame from the BS to the UE or via an uplink radio frame from the UE to the BS).

[0028] The present disclosure provides a method and system for a terminal or UE to complete initial access to a BS with reduced delay. In some embodiments, the UE uses a PRACH aggregation or preamble aggregation scheme before the response time window expires to reduce the delay of initial access caused by the retransmission of the PRACH. This also enhances the coverage of the uplink initial access channel (e.g., the PRACH channel). In some embodiments, the UE also uses the PRACH aggregation or preamble aggregation scheme to find the best transmit beam with reduced delay during the initial access process. That is, the disclosed method can help the UE find the best transmit beam and at the same time improve the probability of successful access.

[0029] The method disclosed in the present teaching can be implemented in a wireless communication network, where the BS and the UE can communicate with each other via a communication link (e.g., via a downlink radio frame from the BS to the UE or via an uplink radio frame from the UE to the BS). In various embodiments, the BS in the present disclosure can be referred to as the network side, and can include or be implemented as a next-generation node B (gNB), an E-UTRAN node B (eNB), a transmission / reception point (TRP), an access point (AP), an AP MLD, a non-ground receiving point for satellite / hot air balloon / unmanned aerial vehicle (UAV) communication, a radio transceiver in a vehicle in a vehicle-to-vehicle (V2V) wireless network, etc.; and the UE in the present disclosure can be referred to as a terminal, and can include or be implemented as a mobile station (MS), a station (STA), a non-AP MLD, a ground device for satellite / hot air balloon / unmanned aerial vehicle (UAV) communication, a radio transceiver in a vehicle in a vehicle-to-vehicle (V2V) wireless network, etc.

[0030] In various embodiments of the present teachings, according to various embodiments of the present disclosure, the two ends of the communication (e.g., BS and UE) may be described herein as non-limiting examples of a "wireless communication node" and a "wireless communication device," respectively, and various embodiments thereof may practice the methods disclosed herein and may be capable of wireless and / or wired communication.

[0031] Figure 1 1 shows an exemplary communication network 100 in which the techniques disclosed herein may be implemented according to an embodiment of the present disclosure. Figure 1 As shown, an exemplary communication network 100 includes a base station (BS) 101 and a plurality of UEs (UE 1 110, UE 2 120, ..., UE 3 130), wherein BS 101 can communicate with the UEs according to a wireless protocol. A UE can enter the coverage of BS 101 and intend to communicate with BS 101. In order to communicate with BS 101, the UE first performs an initial access to BS 101, for example, following a random access procedure.

[0032] Figure 2An exemplary four-step random access process 200 is shown in FIG. Figure 2 As shown, UE 210 transmits a message (Msg) 1 to BS 220 at operation 201. In this example, Msg 1 includes an aggregation of preambles, i.e., multiple copies of the same preamble, to increase the probability of successfully accessing BS 220. Once BS 220 successfully receives Msg 1 (e.g., successfully receives at least one copy of the preamble), BS 220 will send Msg 2 back to UE 210 at operation 202, including a medium access control (MAC) random access response (RAR) as a response to the preamble. When BS 220 receives multiple copies of the same preamble, BS 220 can generate Msg 2 based on the combination of the multiple preamble copies. MAC RAR can include an uplink (UL) grant and a temporary cell radio network temporary identifier (TC-RNTI). After receiving the MAC RAR, at operation 203, the UE 210 transmits Msg 3 to the BS 220 according to the physical uplink shared channel (PUSCH) grant carried in the MAC RAR. After receiving Msg 3, the BS 220 will send Msg 4 back to the UE 210 at operation 204, where some contention conflict resolution identification (ID) will be included for the purpose of contention conflict resolution. Although a four-step random access channel (RACH) process is shown here, according to some embodiments of the present disclosure, the preamble aggregation scheme disclosed herein can also be implemented through a two-step RACH process to further speed up the entire initial access process and significantly reduce the overall initial access delay of the communication network.

[0033] Figure 3 1 shows a block diagram of a base station (BS) 300 according to some embodiments of the present disclosure. BS 300 is an example of a node that can be configured to implement the various methods described herein. Figure 3 As shown, BS 300 includes a housing 340, which contains a clock 302, a processor 304, a memory 306, a transceiver 310 including a transmitter 312 and a receiver 314, a power module 308, a random access message analyzer 320, a random access message generator 322, a RACH opportunity / synchronization signal block (RO / SSB) relationship configurator 324 and a preamble code aggregation configurator 326.

[0034] In the present embodiment, clock 302 provides timing signals to processor 304 for controlling the timing of all operations of BS 300. Processor 304 controls the general operation of BS 300 and may include one or more processing circuits or modules, such as a central processing unit (CPU) and / or a general purpose microprocessor, a microcontroller, a digital signal processor (DSP), a field programmable gate array (FPGA), a programmable logic device (PLD), a controller, a state machine, gating logic, discrete hardware components, a dedicated hardware finite state machine, or any other suitable circuits, devices, and / or structures that can perform computations and other operations on data.

[0035] The memory 306, which may include a read-only memory (ROM) and a random access memory (RAM), may provide instructions and data to the processor 304. A portion of the memory 306 may also include a non-volatile random access memory (NVRAM). The processor 304 typically performs logic and arithmetic operations based on program instructions stored in the memory 306. The instructions (also referred to as software) stored in the memory 306 may be executed by the processor 304 to perform the methods described herein. The processor 304 and the memory 306 together form a processing system that stores and executes software. As used herein, "software" refers to any type of instruction that can configure a machine or device to perform one or more desired functions or processes, whether it refers to software, firmware, middleware, microcode, etc. Instructions may include code (e.g., source code format, binary code format, executable code format, or any other suitable code format). When executed by one or more processors, the instructions cause the processing system to perform the various functions described herein.

[0036] The transceiver 310 including a transmitter 312 and a receiver 314 allows the BS 300 to transmit data to and receive data from a remote device (e.g., another BS or UE). The antenna 350 is typically attached to the housing 340 and electrically coupled to the transceiver 310. In various embodiments, the BS 300 includes (not shown) multiple transmitters, multiple receivers, and multiple transceivers. In one embodiment, the antenna 350 is replaced by a multi-antenna array 350, which can form multiple beams, each beam pointing to a different direction. The transmitter 312 can be configured to wirelessly transmit packets with different packet types or functions, which are generated by the processor 304. Similarly, the receiver 314 is configured to receive packets with different packet types or functions, and the processor 304 is configured to process packets of multiple different packet types. For example, the processor 304 can be configured to determine the type of packet and process the packet and / or the field of the packet accordingly.

[0037] In a communication system including a BS 300 that can serve one or more UEs, the BS 300 can receive a random access request from the UE for accessing the BS 300. In one embodiment, the random access message analyzer 320 receives a first message from the UE via the receiver 314, the first message including a plurality of copies of a preamble for accessing the BS 300. The number of copies can be an integer greater than 1. The copies of the preamble can be carried by different uplink random access channel (RACH) opportunities, respectively.

[0038] In one embodiment, the random access message generator 322 generates a second message and transmits the second message including a response to the first message to the UE via the transmitter 312. The UE will use the response time window to monitor the second message within the response time window. Before the response time window expires, the UE transmits all copies of the preamble.

[0039] In this example, the RO / SSB relationship configurator 324 can configure the mapping relationship between the downlink synchronization signal block (SSB) and the uplink RACH opportunity (RO). In various embodiments, based on the mapping relationship, the uplink RO carrying the copy of the preamble is mapped to the same downlink SSB or different SSB. The copies of the preamble can have the same preamble index.

[0040] In one embodiment, each copy of the preamble is received using a different uplink transmit beam; and the uplink ROs carrying the copies of the preamble are mapped to the same downlink SSB. The second message may be transmitted to the UE along with an implicit indication. The second message includes a response to at least one copy of the preamble. The implicit indication may indicate the best beam in the uplink transmit beam used to transmit the copies of the preamble. The best beam may be used to perform subsequent uplink transmissions by the UE.

[0041] In another embodiment, the uplink ROs carrying the copies of the preamble have a first number equal to the number of copies. The copies of the preamble are received using uplink transmit beams having a second number less than the first number. The association between the uplink ROs and the uplink transmit beams is in accordance with a pattern determined by the BS 300 or the UE.

[0042] In this example, the preamble aggregation configurator 326 may generate an indication indicating the preamble aggregation level configured for the UE, and transmit the indication to the UE via the transmitter 312, so that the UE can determine the number of copies based on the preamble aggregation level. The preamble aggregation configurator 326 may configure different parameters related to preamble aggregation. In one example, the preamble aggregation configurator 326 may directly configure the maximum value of the preamble aggregation level. In another example, the preamble aggregation configurator 326 may configure the maximum value of the uplink RO mapped to the same downlink SSB based on the parameters of the SSB for each RO. In yet another example, the preamble aggregation configurator 326 may configure the actual preamble aggregation level, which indicates the number of copies of the preamble that the UE will use for aggregation. In one embodiment, if applicable, the UE determines the preamble aggregation level, i.e., the number of copies of the preamble is not greater than the maximum value. In various embodiments, the maximum value may be configured as any integer greater than 1. In various embodiments, the maximum value may be implicitly determined to be one of 2, 4, or 8 based on the inverse of the parameters of the SSB for each RO.

[0043] In one embodiment, the uplink RO carrying the copy of the preamble is determined based on a subset of the entire set of ROs configured according to the maximum value. The subset is determined by the UE or configured by the BS 300 with configuration of the subset size or number of subsets.

[0044] In one embodiment, the RO indexes of the uplink ROs carrying the copies of the preamble are continuous; the uplink ROs are continuously allocated in one of the time domain, the frequency domain or the time-frequency hybrid domain. In this embodiment, the uplink ROs are selected from the RO resource set shared by UEs with and without preamble aggregation.

[0045] In another embodiment, the RO indexes of the uplink ROs carrying the copies of the preamble are continuous; the uplink ROs are continuously allocated in one of the time domain, the frequency domain, or the time-frequency hybrid domain. However, in this embodiment, the uplink RO is selected from one of a plurality of aggregated RO resource sets, which are different from and not shared with the traditional RO resource set used by the UE without preamble aggregation. The aggregated RO resource sets are respectively associated with different preamble aggregation levels.

[0046] In yet another embodiment, the RO index of the uplink RO carrying the copy of the preamble is discontinuous; the uplink RO is discontinuously distributed in one of the time domain, the frequency domain or the time-frequency hybrid domain. In this embodiment, the uplink RO is selected from the RO resource set shared by UEs with and without preamble aggregation.

[0047] In another embodiment, the RO index of the uplink RO carrying the copy of the preamble is discontinuous; the uplink RO is discontinuously distributed in one of the time domain, the frequency domain, or the time-frequency hybrid domain. However, in this embodiment, the uplink RO is selected from at least one aggregation set of the traditional RO resource set and the multiple aggregated RO resource sets. The number of at least one aggregation set is determined based on the preamble aggregation level. The traditional RO resource set is shared by UEs with and without preamble aggregation. However, the aggregated RO resource set is only used by UEs with preamble aggregation.

[0048] In different embodiments, the RO index of the uplink RO carrying the copy of the preamble is discontinuous; the uplink RO is discontinuously distributed in one of the time domain, the frequency domain, or the time-frequency hybrid domain. However, in this embodiment, the uplink RO is selected from one of the traditional RO resource set and multiple aggregated RO resource sets; the traditional RO resource set is shared by UEs with and without preamble aggregation. The aggregated RO resource sets are respectively associated with different preamble aggregation levels and are only used by UEs with preamble aggregation.

[0049] In this example, the preamble aggregation configurator 326 may also generate an indicator indicating that the BS 300 supports the combination of multiple preamble receptions, which is transmitted to the UE via the transmitter 312. Upon receiving the indication, the UE may determine whether to perform preamble aggregation based on the transmit power. For example, a first message is transmitted by the UE using preamble aggregation based on a determination that the transmit power of the UE reaches or exceeds a maximum power based on power ramping for random access, and the UE does not access the BS 300. In one embodiment, when the power ramping counter increases after the first message is transmitted by the UE, the random access message generator 322 may further receive an additional first message with an increased preamble aggregation level from the UE.

[0050] The random access message generator 322 may generate the second message based on a combination of all successfully received copies of the preamble. In one embodiment, the second message includes an indication indicating the preamble aggregation level associated with the first message, so that any device receiving the second message can determine whether the second message is intended for the device based on the indication.

[0051] The power module 308 may include a power source (such as one or more batteries) and a power regulator to provide power to the Figure 3 Each of the above modules in provides regulated power. In some embodiments, if BS 300 is coupled to a dedicated external power source (eg, a wall outlet), power module 308 may include a transformer and a power conditioner.

[0052] The various modules discussed above are coupled together via a bus system 330. The bus system 330 may include a data bus, and, for example, a power bus, a control signal bus, and / or a status signal bus in addition to the data bus. It will be appreciated that the modules of the BS 300 may be operably coupled to each other using any suitable technology and medium.

[0053] As used herein, the term "layer" refers to an abstract layer of a layered model (such as the Open Systems Interconnection (OSI) model) that divides a communication system into abstract layers. A layer serves the immediately higher layer above it and is served by the immediately lower layer below it.

[0054] Although in Figure 3 , multiple separate modules or components are shown, but those skilled in the art will understand that one or more of the modules can be combined or implemented together. For example, the processor 304 can not only implement the functions described above about the processor 304, but also implement the functions described above about the random access message analyzer 320. On the contrary, Figure 3 Each module shown may be implemented using multiple individual components or elements.

[0055] Figure 4 BS (eg Figure 3 A flowchart of a method 400 for performing preamble aggregation in a random access process performed by a BS 300 in FIG. 4 . At operation 410, the BS transmits an indication to the UE indicating that the BS supports the merging of multiple preamble receptions. At operation 420, the BS may selectively configure parameters and resources for the UE to perform random access to the BS with preamble aggregation. At operation 430, the BS receives and analyzes a first message including multiple copies of the preamble from the UE before the response time window expires. At operation 440, the BS generates a second message including a response to the first message based on the merging of all successfully received copies of the preamble. At operation 450, the BS transmits a second message to the UE, the second message including an indication of a preamble aggregation level associated with the first message. According to various embodiments, the order of the above operations may be changed.

[0056] Figure 5 1 is a block diagram of a user equipment (UE) 500 according to some embodiments of the present disclosure. UE 500 is an example of a device that can be configured to implement the various methods described herein. Figure 5As shown, UE 500 includes a housing 540, which contains a clock 502, a processor 504, a memory 506, a transceiver 510 including a transmitter 512 and a receiver 514, a power module 508, a random access message generator 520, a random access message analyzer 522, a RO / SSB relationship determiner 524, and a preamble code aggregation determiner 526.

[0057] In this embodiment, clock 502, processor 504, memory 506, transceiver 510, and power module 508 operate in a manner similar to clock 302, processor 304, memory 306, transceiver 310, and power module 308 in BS 300. Antenna 550 or multiple antenna array 550 is typically attached to housing 540 and electrically coupled to transceiver 510.

[0058] In a communication system, UE 500 may want to access a BS for data transmission. In one embodiment, a random access message generator 520 may generate a first message including multiple copies of a preamble for accessing the BS. The number of copies may be an integer greater than 1. In one embodiment, the random access message generator 520 transmits a first message for accessing the BS to the BS via a transmitter 512. The copies of the preamble may be carried by different uplink random access channel (RACH) opportunities, respectively.

[0059] In one embodiment, the random access message analyzer 522 can monitor within a response time window that the second message includes a response to the first message from the BS. Before the response time window expires, all copies of the preamble are transmitted.

[0060] The RO / SSB relationship determiner 524 in this example can determine the mapping relationship between the downlink synchronization signal block (SSB) and the uplink RACH opportunity (RO). In various embodiments, based on the mapping relationship, the uplink RO carrying the copy of the preamble is mapped to the same downlink SSB or different downlink SSB. The copies of the preamble can have the same preamble index.

[0061] In one embodiment, each copy of the preamble is transmitted using a different uplink transmit beam; and the uplink RO carrying the copy of the preamble is mapped to the same downlink SSB. The random access message analyzer 522 can receive a second message with an implicit indication from the BS via the receiver 514. The second message includes a response to at least one successfully received copy of the preamble. The implicit indication can indicate the best beam in the uplink transmit beam for transmitting the copy of the preamble. The best beam can be used for future uplink transmissions performed by the UE 500.

[0062] In another embodiment, the uplink ROs carrying the copies of the preamble have a first number equal to the number of copies. The copies of the preamble are received using uplink transmit beams having a second number less than the first number. The association between the uplink ROs and the uplink transmit beams is in accordance with a pattern determined by the BS or UE 500.

[0063] In this example, the preamble aggregation determiner 526 may receive an indication of the preamble aggregation level configured for the UE 500 from the BS via the receiver 514, and analyze the indication so that the preamble aggregation determiner 526 may determine the number of copies based on the preamble aggregation level. The preamble aggregation determiner 526 may determine different parameters related to preamble aggregation. For example, the preamble aggregation determiner 526 may determine the number of copies as a preamble aggregation level that is not greater than the maximum value of the uplink RO mapped to the same downlink SSB, where the maximum preamble aggregation level may be implicitly or directly indicated from the BS. The maximum value may be determined based on a parameter of the SSB for each RO or an integer greater than 1. In various embodiments, the maximum value may be determined to be one of 2, 4, or 8 based on the inverse of the parameter of the SSB for each RO.

[0064] In one embodiment, the preamble aggregation determiner 526 may determine the uplink RO carrying the copy of the preamble based on a subset of the entire set of ROs configured according to the maximum value. The subset is determined by the UE 500 or configured by the BS with a configuration of the subset size or the number of subsets.

[0065] In one embodiment, the RO indexes of the uplink ROs carrying the copies of the preamble are continuous; the uplink ROs are continuously allocated in one of the time domain, the frequency domain or the time-frequency hybrid domain. In this embodiment, the uplink ROs are selected from the RO resource set shared by UEs with and without preamble aggregation.

[0066] In another embodiment, the RO indexes of the uplink ROs carrying the copies of the preamble are continuous; the uplink ROs are continuously allocated in one of the time domain, the frequency domain, or the time-frequency hybrid domain. However, in this embodiment, the uplink RO is selected from one of a plurality of aggregated RO resource sets, which are different from and not shared with the traditional RO resource sets used by UEs without preamble aggregation. The aggregated RO resource sets are respectively associated with different preamble aggregation levels.

[0067] In yet another embodiment, the RO index of the uplink RO carrying the copy of the preamble is discontinuous; the uplink RO is discontinuously distributed in one of the time domain, the frequency domain or the time-frequency hybrid domain. In this embodiment, the uplink RO is selected from the RO resource set shared by UEs with and without preamble aggregation.

[0068] In yet another embodiment, the RO index of the uplink RO carrying the copy of the preamble is discontinuous; the uplink RO is discontinuously distributed in one of the time domain, the frequency domain, or the time-frequency hybrid domain. However, in this embodiment, the uplink RO is selected from at least one aggregation set of the traditional RO resource set and the multiple aggregated RO resource sets. The number of at least one aggregation set is determined based on the preamble aggregation level. The traditional RO resource set is shared by UEs with and without preamble aggregation. However, the aggregated RO resource set is only used by UEs with preamble aggregation.

[0069] In different embodiments, the RO index of the uplink RO carrying the copy of the preamble is discontinuous; the uplink RO is discontinuously distributed in one of the time domain, the frequency domain, or the time-frequency hybrid domain. However, in this embodiment, the uplink RO is selected from one of the traditional RO resource set and multiple aggregated RO resource sets; the traditional RO resource set is shared by UEs with and without preamble aggregation. The aggregated RO resource sets are respectively associated with different preamble aggregation levels and are only used by UEs with preamble aggregation.

[0070] In this example, the preamble aggregation determiner 526 may also receive an indication from the BS via the receiver 514, indicating that the BS supports the merging of multiple preamble receptions. Upon receiving the indication, the UE 500 may determine whether to perform preamble aggregation based on the transmit power. For example, the preamble aggregation determiner 526 may determine that the transmit power of the UE 500 reaches the maximum power based on the power climb used to access the BS, and that the UE 500 does not access the BS. Based on this determination, the first message is transmitted with preamble aggregation. In one embodiment, when the power climb counter increases after transmitting the first message, the random access message analyzer 522 may generate an additional first message with an increased preamble aggregation level and transmit the message to the BS via the transmitter 512.

[0071] In one embodiment, the second message is generated by the BS based on a combination of all successfully received copies of the preamble. The random access message analyzer 522 can also receive a response message to the access message from the BS via the receiver 514 and analyze the message. The response message includes an indication of the preamble aggregation level associated with the access message. Based on the analysis of the indication, the random access message analyzer 522 can determine whether the response message is for the UE 500.

[0072] The various modules discussed above are coupled together via a bus system 530. The bus system 530 may include a data bus, and, for example, a power bus, a control signal bus, and / or a status signal bus in addition to the data bus. It should be understood that the modules of the UE 500 may be operably coupled to each other using any suitable technology and medium.

[0073] Although in Figure 5 , but a person skilled in the art will appreciate that one or more of the modules may be combined or implemented together. For example, the processor 504 may implement not only the functions described above regarding the processor 504, but also the functions described above regarding the random access message generator 520. On the contrary, Figure 5 Each module shown in can be implemented using multiple individual components or elements.

[0074] Figure 6 UE (eg Figure 5 500 in FIG. 1 ) for performing preamble aggregation in a random access process. At operation 610, the UE determines that the BS to be accessed supports the combination of multiple preamble receptions. At operation 620, the UE determines that the transmit power of the UE reaches the maximum power for random access to a BS without preamble aggregation. At operation 630, the UE determines the parameters and configuration for performing random access to a BS with preamble aggregation. At operation 640, the UE generates a first message including multiple copies of the preamble before the response time window expires and transmits it to the BS. At operation 650, the UE receives and analyzes a response message including an indication and an access message from the BS. At operation 660, the UE determines whether the response message is for the UE based on an indication indicating a preamble aggregation level associated with the access message. According to various embodiments, the order of the above operations can be changed.

[0075] Now, different embodiments of the present disclosure will be described in detail below. Note that the features of the embodiments and examples in the present disclosure can be combined with each other in any way without conflict.

[0076] In the first embodiment, different PRACH aggregation or preamble aggregation schemes are described. Although PRACH transmission in the conventional method occurs only once before the response window expires, and retransmission of PRACH may occur only after the response window expires, the present teaching discloses a solution for providing multiple PRACH transmissions before the response window expires.

[0077] The scheme of multiple PRACH transmissions can be based on repetition or beam switching. These schemes or a combination of these schemes can be referred to as PRACH aggregation or preamble aggregation. Beam switching can also be viewed as a repetition of preambles with different uplink (UL) transmit (Tx) beams. According to different embodiments of the present teachings, the concept of PRACH aggregation can also cover other schemes, not limited to repetition or beam switching.

[0078] In one embodiment, PRACH is a preamble sequence carried by a time-frequency instance called a RACH opportunity (RO). In most cases, the preamble sequence may have an additional cyclic prefix (CP) before the preamble or a guard period (GP) after the preamble, wherein the preamble with the cyclic prefix and / or the guard period constitutes the PRACH. In this embodiment, multiple PRACH transmissions or PRACH aggregation is mainly related to multiple PRACHs in multiple ROs, but it can also be applied to different preamble sequence aggregations.

[0079] Fig. 7A An exemplary scheme 710 for preamble aggregation based on repetition of multiple PRACH transmissions (ie, multiple copies of the preamble) with the same UL Tx beam in 4 RACH opportunities with the same preamble index is shown in accordance with some embodiments of the present disclosure. Figure 7B Another exemplary scheme 720 for preamble aggregation based on beam switching with different UL Tx beams in 4 RACH opportunities for multiple PRACH transmissions with the same preamble index according to some embodiments of the present disclosure is shown.

[0080] In this example, the aggregation level or size is 4, but it can also be other values, such as any integer greater than 1. The RO index in the aggregation group increases continuously from RO1 to RO4. However, the RO index is just a logical number of RACH opportunities. Therefore, the physical ROs in the group may not be continuous in the physical time-frequency domain. For example, a physical RO may cross a time slot boundary or be separated in time or frequency from other physical ROs.

[0081] about Fig. 7A In the scheme 710 shown in FIG, the repetition of PRACH occurs in multiple ROs. The BS or network can combine multiple receptions of multiple PRACHs to obtain a combining gain and improve uplink coverage performance and / or a probability of successful access. In the NR system, the BS or network can broadcast an association between a downlink SSB (synchronization signal block) and an uplink RO, which means that there is a mapping relationship between the SSB and the RO. Fig. 7A In the scheme 710 shown in FIG. 7 , the ROs involved in the repetition of the PRACH from one UE are all associated with the same SSB.

[0082] about Figure 7BIn the scheme 720 shown in , there are two different cases, namely, whether the ROs in the aggregation group are mapped to the same SSB or different SSBs. If the ROs containing PRACH are mapped to the same SSB, it is called case (B-1). In this case, the UE attempts to find the best or sufficiently good transmit beam through beam switching in an aggregation group. When the network successfully receives one or more PRACHs, the network can respond to one or any one of the multiple successfully received PRACHs and send Msg 2 to the UE. The random access radio network temporary identifier (RA-RNTI) scrambled in Msg 2 on the physical downlink control channel (PDCCH) can implicitly indicate the best or good transmit beam for the UE, because the RA-RNTI is calculated based on the time-frequency information of the specific RO. The indication of the best UL Tx beam can help the next or subsequent uplink transmission (e.g., the transmission of Msg 3). From the network's perspective, the network can combine the reception of PRACH with different UL Tx beams, which can also improve coverage, reduce the delay of initial access and increase the probability of successful access.

[0083] In one example, when the network successfully receives multiple copies of the preamble transmitted on different UL Tx beams, the network can select the UL Tx beam corresponding to the maximum or appropriate receive power of the preamble copies. The network can implicitly inform the UE about the selected beam based on the scrambled RA-RNTI in Msg 2. Appropriate receive power means that the receive power meets a predefined threshold.

[0084] If the RO containing the PRACH is mapped to different SSBs, it is called case (B-2). In this case, the UE can transmit PRACH on different ROs associated with different SSBs before the response window expires. This scheme is more suitable for UEs that receive multiple SSBs with almost the same or similar quality. The UE transmits multiple PRACHs to inform the network of the reception status of the SSBs, which can reduce the overall delay of the initial access process.

[0085] Repetition and beam switching can be combined together in one aggregation group as a hybrid transmission mode, which may be referred to as a hybrid mode or a hybrid scheme. Fig. 8A and Figure 8B Some examples of hybrid schemes are shown in . These are typical patterns for hybrid schemes.

[0086] Fig. 8A An exemplary hybrid scheme 810 for preamble aggregation according to some embodiments of the present disclosure is shown. Fig. 8AIn the hybrid scheme 810 shown in FIG, PRACH is repeated twice at RO1 and RO2, the beam is switched at RO3, and PRACH is repeated again at RO4. Figure 8B Another exemplary hybrid scheme 820 for preamble aggregation according to some embodiments of the present disclosure is shown. Figure 8B In the hybrid scheme 820 shown in FIG. 8 , the beam of the PRACH is switched to the second beam at RO2 compared to the first beam at RO1, and switched back to the first beam at RO3, and then switched again to the second beam at RO4. It seems as if the PRACH in RO3 and RO4 is copied from RO1 and RO2, respectively.

[0087] Similar to cases (B-1) and (B-2), the ROs in a group may be mapped to only one SSB or to multiple SSBs. For the hybrid scheme, if the ROs in a group are mapped to one same SSB, the UE does not need to have a fixed combination pattern of repetition and beam switching. At any RO, the UE can flexibly and freely determine whether the action is to perform repetition or beam switching. From the network's perspective, there is no difference in the energy accumulation from multiple PRACH receptions, whether PRACH aggregation is based on repetition or beam switching. If the ROs in a group are mapped to multiple SSBs, the network can configure the pattern of the hybrid scheme.

[0088] Although Figures 7A-8B The RO in the example shown in is based on a time domain instance, but the RO may also be based on a frequency domain instance, or a time-frequency mixed instance. Multiple PRACH transmissions in the frequency domain instance may only be applied to UEs that have the capability to support multiple PRACH transmissions simultaneously.

[0089] For all the above PRACH aggregation schemes, if the UE's capabilities meet the requirements, the network can determine which scheme can be configured. In some cases, if there is no configuration from the network, the UE can make its own decision on the scheme selection. For example, in the case where the ROs in the group are mapped to the same SSB, the UE can freely select one of the above schemes on the premise that the network indicates to the UE that the network supports the merging of multiple PRACH receptions.

[0090] In the second embodiment, the PRACH aggregation size or level is described. Figures 7A-8B In the example shown in , if the RO in the group is mapped to only one SSB, the PRACH aggregation size or level is 4. This value is the number of multiple PRACH transmissions. The network can configure the maximum aggregation level or the actual aggregation level for the UE. Optionally, the aggregation level can be determined by the UE itself.

[0091] For the case where the aggregation level is determined by the UE, the UE measures the downlink signal power level or path loss to evaluate the received signal quality and determine the appropriate aggregation level for multiple PRACH transmissions. There is no specific upper limit on the value of the aggregation level, where the maximum value of the aggregation level depends on the MCL (maximum coupling loss) in the system. For example, when the UE reaches the MCL, the accumulated signal to interference and noise ratio (SINR) of multiple PRACH receptions should meet the minimum sensitivity requirement.

[0092] In one embodiment, if multiple PRACH transmissions share legacy RO resources with UEs without aggregation, the maximum value of the aggregation level is limited by the ssb-perRACH-Occasion parameter. In one embodiment, the value set of ssb-perRACH-Occasion is {1 / 8, 1 / 4, 1 / 2, 1, 2, 4, 8, 16}, which means that the number of ROs for each SSB is the reciprocal of ssb-perRACH-Occasion, and the number of ROs for the SSB is {8, 4, 2, 1, 1 / 2, 1 / 4, 1 / 8, 1 / 16}. Assuming that the ROs for preamble aggregation in the group are mapped to the same SSB, only {8, 4, 2} of the values ​​of RO for each SSB can support multiple PRACH transmissions. For example, when ssb-perRACH-Occasion = 1 / 8, the maximum value of the aggregation level is 8. The network can configure the maximum value of the aggregation level to be the reciprocal of ssb-perRACH-Occasion, which can be 2, 4, or 8. In this scenario, for the aggregation level determined by the UE, it should not exceed the inverse of ssb-perRACH-Occasion.

[0093] Regardless of whether the maximum aggregation level is configured by the network or determined by the UE itself, the UE has the right to determine the actual aggregation level, which is no greater than the maximum aggregation level. For example, if the maximum aggregation level is 4, the UE can repeat PRACH 2 times.

[0094] In general, the UE may determine to use a subset of ROs in the entire set of ROs determined by the maximum aggregation level. Fig. 9 FIG. 9 shows an exemplary allocation 900 of random access channel (RACH) opportunities for different aggregation levels according to some embodiments of the present disclosure. Fig. 9As shown, in this case, the entire set of ROs is: {RO1, RO2, RO3, RO4}, and the UE can use different RO combinations or subsets for different preamble aggregation levels. For example, in the set of {RO1, RO2, RO3, RO4}, the UE can use any one of RO1, RO2, RO3, RO4 as level 1 aggregation; the UE can also use any one of {RO1, RO2}, {RO3, RO4} in the set of {RO1, RO2, RO3, RO4} as level 2 aggregation; the UE can also use the set of {RO1, RO2, RO3, RO4} as level 4 aggregation. For the same aggregation level, RO subsets do not overlap with each other.

[0095] In addition to or as an alternative to the RO subset size determined by the UE itself, the RO subset size of the aggregation group may also be indicated by the network to the UE. In one example, the indication may indicate that the maximum size of the RO group is 4, while the network configures the subset size to 2, which means that only level 2 aggregation with subsets of {RO1, RO2}, {RO3, RO4} can be adopted. In one embodiment, the indication of the subset size may be replaced by the number of subsets. In the above example, the network may indicate that the number of subsets is 2.

[0096] In the third embodiment, distributed and localized PRACH resource allocation for preamble aggregation is described. As described above, the RO index in the aggregation group is a logical number of RACH opportunities and increases continuously in the first embodiment. The ROs in the group with continuously increasing indices are regarded as localized PRACH resources for aggregation. Alternatively, the distributed PRACH resource arrangement for ROs in the aggregation group can be applied to all embodiments.

[0097] Distributed resource allocation means that the index of resources is not continuous. In the following four examples of resource allocation, the first to third examples are shown to illustrate how to allocate resources and how to use distributed resources for PRACH aggregation; while the fourth example is to allocate separate RO resource sets for different aggregation sizes or levels.

[0098] According to the first example, Fig.10 Resource allocation 1000 of distributed RACH opportunities (RO) for preamble aggregation is shown. Fig.10, legacy UEs without PRACH aggregation and UEs with PRACH aggregation share the same set of RO resources in {RO1, RO2, …, RO20, RO21, …, RO40}. In this example, for UEs with PRACH aggregation, the aggregation level is 2, and assuming that there are 20 SSBs in this example, two subsets of RO resources are determined as {RO1, …, RO20} and {RO21, …, RO40}. The aggregation groups are {RO1, RO21}, {RO2, RO22}, …, {RO20, RO40}. Therefore, in each group, the index of RO is discontinuous, and the interval between two RO indexes in the same group is a constant, which is 20 in this example. The aggregation level can be extended to larger numbers such as 4, 8, 16, etc., which means that more subsets of all RO resources are also divided and determined. If there are more than 2, 4, 8, 16 mapping periods within the SSB-to-RO association period, this distributed resource scheme has better backward compatibility because there is no need to limit the parameter of ssb-perRACH-Occasion to less than 1. Due to the larger RO index interval in the group, the latency of aggregation may be longer. Since RO resources are shared by legacy UEs (UEs without PRACH aggregation) and UEs with PRACH aggregation, it is difficult to blindly distinguish legacy UEs from UEs with PRACH aggregation from the network side. In this example, legacy UEs without PRACH aggregation and UEs with PRACH aggregation share the same set of RO resources, but the PRACH resources used for one aggregation group are distributed.

[0099] According to the second example, Fig.11 Another exemplary resource allocation 1100 of distributed RO for preamble aggregation is shown. Fig.11 , legacy UEs without PRACH aggregation and UEs with PRACH aggregation partially share the RO resource set. The legacy RO set is shared between legacy UEs and UEs with PRACH aggregation. However, the newly added aggregated RO set 1 and aggregated RO set 2 are only used for UEs with PRACH aggregation and are not used by legacy UEs. For the case where the aggregation level is 2, both the legacy RO set and the aggregated RO set 1 are involved. For example, RO1 in the legacy RO set and RO1 in the aggregated RO set 1 are aggregated together. For the case where the aggregation level is 4, the legacy RO set, the aggregated RO set 1, and the aggregated RO set 2 are all involved. For example, RO1 in the legacy RO set, RO1 in the aggregated RO set 1, and RO1 and RO2 in the aggregated RO set 2 are aggregated together to construct four repetitions or beam switching. If more aggregated RO sets are provided, more aggregation sizes or levels are allowed. In this example of distributed resource arrangement, RO sets can be cascaded for legacy UEs and UEs with different aggregation levels, such as Fig.11 shown.

[0100] According to the second example, Fig.12 Another exemplary resource allocation 1200 for distributed RO for preamble aggregation is shown. Fig.12 , legacy UEs without PRACH aggregation and UEs with PRACH aggregation partially share the RO resource set. The legacy RO set is shared between legacy UEs and UEs with PRACH aggregation. Fig.11 Unlike the allocation in , the newly added aggregated RO set is not used in cascade. For each given aggregation level, only one aggregated RO set is used together with the traditional RO set for PRACH aggregation. For example, for the case of aggregation level 2, only aggregated RO set 1 and the traditional RO set are involved in PRACH aggregation. For the case of aggregation level 4, only aggregated RO set 2 and the traditional RO set are involved in PRACH aggregation, and aggregated RO set 1 is irrelevant to the case of aggregation level 4. In this example of distributed resource arrangement, the aggregated RO set will be used separately and individually with the traditional RO set for UEs with different aggregation levels.

[0101] According to the second example, Fig.13 An exemplary resource allocation 1300 for local RO for preamble aggregation is shown. Fig.13 , legacy UEs without PRACH aggregation and UEs with PRACH aggregation do not share any RO resources. Each aggregated RO set is intended to be used for the corresponding aggregation level accordingly. For example, aggregated RO set 1 is only used for PRACH aggregation with aggregation level 2; aggregated RO set 2 is only used for PRACH aggregation with aggregation level 4. More aggregation levels can be performed using more separate aggregated RO sets. In this example, the RO resource arrangement for PRACH aggregation in each aggregation set is localized. In other examples, the RO resource arrangement for PRACH aggregation in each aggregation set can also be distributed (not shown).

[0102] In a fourth embodiment, PRACH aggregation with power climbing is described. The UE has the right to decide when to process PRACH aggregation. A typical condition for PRACH aggregation is that the UE transmit power has reached the maximum allowed power level. PRACH aggregation can then be used to improve initial access performance. In one example, for each transmission failure, the power climbing counter is increased by 1 to indicate that the transmit power level has increased by 1 level. When the power climbing counter k=k0, the UE's transmit power level reaches or exceeds the maximum power. If the power climbing counter keeps running, and when k=k0+1, the UE will aggregate PRACH at aggregation level=2; when k=k0+2, the UE will aggregate PRACH at aggregation level=4. If the power climbing counter keeps running after each attempt, more aggregation levels can be added.

[0103] In a fifth embodiment, an indication in Msg 2 for indicating an aggregation level is described. Since the PRACH resources for a UE with PRACH aggregation and the PRACH resources for a legacy UE may overlap, different second messages (Msg 2) for random access responses on the PDCCH may be scrambled by the same RA-RNTI for legacy UEs and UEs with PRACH aggregation. A UE with PRACH aggregation cannot automatically distinguish whether the random access response is specifically for the UE itself or for a legacy UE. In this embodiment, some additional indications within Msg 2 may be used to enable the UE to identify whether Msg 2 on the PDCCH and PDSCH is for the UE. For example, the network may identify the aggregation level by blind detection of the aggregated PRACH. The network may then generate an indication to indicate the aggregation level of the detected PRACH aggregation and transmit the indication to the UE via Msg 2. In one case, the indication may indicate that the detected aggregation level is 1 to indicate that Msg 2 is for a legacy UE without aggregation.

[0104] According to various embodiments of the present teachings, the network can determine which PRACH aggregation scheme to configure for the UE. If the PRACH aggregation scheme from the network is not configured, the UE can decide the scheme selection on its own. The network can indicate to the UE that the network has the ability to support a combination of multiple PRACH receptions. PRACH aggregation refers to the aggregation of multiple PRACH transmissions in multiple ROs with the same preamble index, or in different preamble sequences. The PRACH aggregation scheme may include PRACH repetition with the same UL Tx beam or beam switching with different UL Tx beams. A mix of repetition and beam switching can also be an alternative to the PRACH aggregation scheme, where the mode of mixed repetition and beam switching can be configured by the network for the UE.

[0105] According to various embodiments of the present teachings, the maximum aggregation level or the actual aggregation level may be configured by the network for the UE, or based on the UE's own determination. If multiple PRACH transmissions share legacy RO resources with a UE without preamble aggregation, the maximum value of the aggregation level is limited by the inverse of the parameter of ssb-perRACH-Occasion. A subset of the entire set of ROs determined by the maximum aggregation level is used for PRACH aggregation. Each subset is determined by the UE itself. Alternatively, the subset size or the number of subsets may be configured for the UE.

[0106] According to various embodiments of the present teachings, the PRACH resources for aggregation can be distributed and / or localized. There are at least five possible resource arrangement schemes to be considered: (1) PRACH resources for aggregation are localized, and legacy UEs without PRACH aggregation and UEs with PRACH aggregation share the same RO resource set; (2) PRACH resources for aggregation are localized in each RO resource set, and different separate RO resource sets are configured for different aggregation sizes or levels, where the legacy PRACH resource set is not allowed to be used for UEs with PRACH aggregation; (3) PRACH resources for aggregation are distributed, where legacy UEs without PRACH aggregation and UEs with PRACH aggregation share the same RO resource set; (4) PRACH resources for aggregation are distributed, where the legacy RO set and the aggregated RO set will be cascaded for UEs with different aggregation levels; (5) PRACH resources for aggregation are distributed, where the aggregated RO set will be separated and used separately with the legacy RO set for UEs with different aggregation levels.

[0107] According to various embodiments of the present teachings, the UE will aggregate PRACH transmissions under the condition that its transmit power reaches or exceeds the maximum transmit power for random access. As the power climbing counter keeps running, the level of PRACH aggregation will increase. In one embodiment, the level of PRACH aggregation can be indicated to the UE by the network via Msg 2.

[0108] Although various embodiments of the present disclosure have been described above, it should be understood that they are presented only by way of example rather than by way of limitation. Similarly, various figures may depict example architectures or configurations, which are provided to enable those of ordinary skill in the art to understand the exemplary features and functions of the present disclosure. However, these people will understand that the present disclosure is not limited to the example architectures or configurations shown, but may be implemented using various alternative architectures and configurations. In addition, as will be appreciated by those of ordinary skill in the art, one or more features of an embodiment may be combined with one or more features of another embodiment described herein. Therefore, the breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments.

[0109] It should also be understood that any reference to an element using the designations "first," "second," etc. herein does not generally limit the quantity or order of those elements. Rather, these designations may be used herein as a convenient method of distinguishing between two or more elements or instances of an element. Thus, reference to a first and a second element does not mean that only two elements may be used, or that the first element must be located before the second element in some manner.

[0110] In addition, those skilled in the art will appreciate that any of a variety of different techniques and technologies may be used to represent information and signals. For example, data, instructions, commands, information, signals, bits, and symbols that may be referenced in the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0111] Those of ordinary skill in the art will further understand that any of the various illustrative logical blocks, modules, processors, devices, circuits, methods, and functions described in conjunction with the aspects disclosed herein may be implemented by electronic hardware (e.g., digital implementations, analog implementations, or a combination of both), firmware, various forms of programs or design code combined with instructions (for convenience, may be referred to herein as "software" or "software modules"), or any combination of these technologies.

[0112] In order to clearly illustrate this interchangeability of hardware, firmware and software, various illustrative components, blocks, modules, circuits and steps have been generally described above with respect to their functionality. Whether these functions are implemented as hardware, firmware or software, or a combination of these technologies, depends on the specific application and the design constraints imposed on the entire system. The technician can implement the functions in various ways for each specific application, but this implementation decision will not lead to deviation from the scope of the present disclosure. According to various embodiments, processors, devices, components, circuits, structures, machines, modules, etc. can be configured to perform one or more functions described herein. As used herein, the term "configured to" or "configured for" regarding a specific operation or function refers to a processor, device, component, circuit, structure, machine, module, etc. that is physically constructed, programmed and / or arranged to perform a specific operation or function.

[0113] In addition, it will be understood by those of ordinary skill in the art that the various illustrative logic blocks, modules, devices, components, and circuits described herein may be implemented within or performed by an integrated circuit (IC), which may include a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, or any combination thereof. The logic blocks, modules, and circuits may further include antennas and / or transceivers to communicate with various components within a network or within a device. A general purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor), multiple microprocessors, one or more microprocessors combined with a DSP core, or any other suitable configuration for performing the functions described herein.

[0114] If implemented in software, the functions may be stored as one or more instructions or codes on a computer-readable medium. Therefore, the steps of the method or algorithm disclosed herein may be implemented as software stored on a computer-readable medium. Computer-readable media include computer storage media and communication media, and communication media include any media that can be enabled to transfer a computer program or code from one location to another. The storage medium can be any available medium that can be accessed by a computer. By way of example and not limitation, such a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage device, or any other medium that can be used to store the desired program code in the form of instructions or data structures and can be accessed by a computer.

[0115] In this document, the term "module" as used herein refers to software, firmware, hardware, and any combination of these elements for performing the relevant functions described herein. In addition, for the purpose of discussion, various modules are described as separate modules; however, as is apparent to those of ordinary skill in the art, two or more modules can be combined to form a single module that performs the relevant functions according to the embodiments of the present disclosure.

[0116] In addition, memory or other memory and communication components may be used in embodiments of the present disclosure. It should be understood that, for clarity, the above description describes embodiments of the present disclosure with reference to different functional units and processors. However, it is apparent that any appropriate functional distribution between different functional units, processing logic elements or domains may be used without departing from the present disclosure. For example, a function described as being performed by a separate processing logic element or controller may be performed by the same processing logic element or controller. Therefore, reference to a specific functional unit is merely a reference to an appropriate device for providing the function, rather than indicating a strict logical or physical structure or organization.

[0117] Various modifications to the implementations described in this disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other implementations without departing from the scope of this disclosure. Therefore, the present disclosure is not intended to be limited to the implementations shown herein, but is to be consistent with the broadest scope consistent with the novel features and principles disclosed herein, as described in the following claims.

Claims

1. A method for preamble aggregation performed by a wireless communication device, the method comprising: Transmitting a first message to a wireless communication node, the first message comprising a plurality of copies of a preamble for accessing the wireless communication node, wherein the number of copies is an integer greater than 1, and wherein the copies of the preamble are respectively carried by different uplink random access channel RACH opportunities; and monitoring, within a response time window, for a second message including a response to the first message from the wireless communication node, wherein all copies of the preamble are transmitted before expiration of the response time window; wherein the copies of the preamble have the same preamble index, The method further comprises: When a power ramp-up counter is incremented after transmitting the first message, an additional first message with an increased preamble aggregation level is transmitted to the wireless communication node, wherein the increase in the power ramp-up counter after transmitting the first message indicates the increase in the preamble aggregation level.

2. The method according to claim 1, further comprising: Determine the mapping relationship between the downlink synchronization signal block SSB and the uplink RACH opportunity RO, wherein: Based on the mapping relationship, the uplink RO carrying the copy of the preamble code is mapped to the same downlink SSB or different SSBs.

3. The method according to claim 2, wherein: Each of the copies of the preamble is transmitted using a different uplink transmit beam; and The uplink RO carrying the copy of the preamble is mapped to the same downlink SSB.

4. The method according to claim 3, further comprising: receiving the second message having an implicit indication from the wireless communication node, wherein: the second message comprising a response to at least one successfully received copy of the preamble, The implicit indication indicates a best beam among the uplink transmit beams for transmitting the copy of the preamble, and The best beam will be used to perform future uplink transmissions to the wireless communication node.

5. The method according to claim 2, wherein: The uplink ROs carrying the copies of the preamble have a first number equal to the number of the copies; transmitting the copy of the preamble using a second number of uplink transmit beams having a smaller number than the first number; and The association between the uplink RO and the uplink transmit beam is in accordance with a pattern determined by the wireless communication node or the wireless communication device.

6. The method according to claim 1, further comprising: receiving, from the wireless communication node, an indication indicating a preamble aggregation level configured for the wireless communication device; as well as The number of repetitions is determined based on the preamble aggregation level.

7. The method according to claim 2, further comprising: The number of repetitions is determined to be a preamble aggregation level no greater than a maximum value of uplink ROs mapped to the same downlink SSB, wherein the maximum value is determined based on a parameter of the SSB for each RO.

8. The method according to claim 1, further comprising: In the absence of access to the wireless communication node, determining based on power ramping that the transmit power of the wireless communication device reaches a maximum power, wherein based on the determination, the first message is transmitted using preamble aggregation.

9. The method according to claim 1, further comprising: An indication is received from the wireless communication node indicating that the wireless communication node supports combining of multiple preamble receptions, wherein the second message is generated by the wireless communication node based on combining all successfully received copies of the preamble.

10. The method according to claim 1, further comprising: receiving a message including a response to an access message from the wireless communication node, wherein the response message includes an indication indicating a preamble aggregation level associated with the access message; and A determination is made based on the indication whether the response message is intended for the wireless communication device.

11. A method for preamble aggregation performed by a wireless communication node, the method comprising: A first message is received from a wireless communication device, the first message comprising a plurality of copies of a preamble for accessing the wireless communication node, wherein: The number of copies is an integer greater than 1. The copies of the preamble are respectively carried by different uplink random access channel RACH opportunities; and transmitting a second message including a response to the first message to a wireless communication device, wherein: the second message being monitored by the wireless communication device within a response time window, transmitting, by the wireless communication device, all copies of the preamble before expiration of the response time window; wherein the copies of the preamble have the same preamble index, The method also includes receiving an additional first message with an increased preamble aggregation level from the wireless communication device when a power ramp-up counter increases after the first message is transmitted by the wireless communication device, wherein the increase in the power ramp-up counter after the first message is transmitted indicates an increase in the preamble aggregation level.

12. The method according to claim 11, further comprising: Configure the mapping relationship between the downlink synchronization signal block SSB and the uplink RACH opportunity RO, where: Based on the mapping relationship, the uplink RO carrying the copy of the preamble code is mapped to the same downlink SSB or different SSBs.

13. The method according to claim 12, wherein: receiving each copy of the preamble using a different uplink transmit beam; and The uplink RO carrying the copy of the preamble is mapped to the same downlink SSB.

14. The method according to claim 13, wherein: The second message is transmitted to the wireless communication device using an implicit indication; the second message comprising a response to at least one of the copies of the preamble; The implicit indication indicates a best beam among the uplink transmit beams for transmitting the copy of the preamble; as well as The best beam will be used for future uplink transmissions by the wireless communication device.

15. The method of claim 12, wherein: The uplink ROs carrying the copies of the preamble have a first number equal to the number of the copies; receiving the copy of the preamble using a second number of uplink transmit beams having a smaller number than the first number; and The association between the uplink RO and the uplink transmit beam is in accordance with a pattern determined by the wireless communication node or the wireless communication device.

16. The method according to claim 12, further comprising: An indication is transmitted to the wireless communication device indicating a preamble aggregation level configured for the wireless communication device, wherein the wireless communication device determines a number of repetitions based on the preamble aggregation level.

17. The method according to claim 12, further comprising: Based on the parameters of the SSB for each RO, the maximum value of uplink ROs mapped to the same downlink SSB is configured, The number of the copies indicates a preamble aggregation level determined by the wireless communication device and is not greater than the maximum value.

18. The method of claim 11, wherein: The first message is transmitted by the wireless communication device using preamble aggregation based on a determination that a transmit power of the wireless communication device reaches a maximum power based on power ramping without access to the wireless communication node.

19. The method according to claim 11, further comprising: transmitting an indication to the wireless communication device, the indication indicating that the wireless communication node supports combining of reception of multiple preambles; as well as The second message is generated based on a combination of all successfully received copies of the preamble.

20. The method of claim 11, wherein: The second message includes an indication of a preamble aggregation level associated with the first message; and Any device receiving the second message determines whether the second message is intended for the device based on the indication.

21. A wireless communication device, comprising a processor and a memory, wherein the memory stores instructions, and when the instructions are executed by the processor, the wireless communication device executes the method according to any one of claims 1 to 10.

22. A wireless communication node, comprising a processor and a memory, wherein the memory stores instructions, and when the instructions are executed by the processor, the wireless communication node executes the method according to any one of claims 11 to 20.

23. A non-transitory computer-readable medium having stored thereon computer-executable instructions for causing a processor to perform the method according to any one of claims 1 to 20.

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