Random Access Channel Configuration in Time Domain for NR in Unlicensed Spectrum

Abstract

Systems, methods, and circuits for adjusting random access channel (RACH) opportunities in unlicensed spectrum to support operations are provided. In one example, a method includes determining a set of preconfigured random access channel (RACH) opportunities (ROs) comprising a plurality of consecutive ROs; deriving a set of adjusted ROs by inserting time gaps between ROs in the set of preconfigured ROs; and transmitting a physical random access channel (PRACH) preamble in at least one RO in the set of adjusted ROs.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 843,077, filed May 3, 2019, entitled “ENHANCEMENTS TO RANDOM ACCESSCHANNEL OCCASION CONFIGURATION IN TIME DOMAIN FOR NR-UNLICENSED,” which is incorporated herein by reference for all purposes. Background Art

[0003] One limiting factor in wireless innovation is spectrum availability. To mitigate this, unlicensed spectrum has been an area of significant interest in expanding LTE availability. In this context, one of the enhancements to LTE in 3GPP Release 13 is the ability to operate in unlicensed spectrum via License Assisted Access (LAA), which extends system bandwidth by leveraging the flexible carrier aggregation (CA) framework introduced by LTE-Advanced systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] Some examples of circuits, devices and / or methods will be described below by way of example only.In this context, reference will be made to the accompanying drawings.

[0005] Figure 1 is a block diagram illustrating example random access channel (RACH) communications in a wireless communication network in accordance with various disclosed aspects.

[0006] Figure 1A is a timing diagram of an exemplary RACH slot in which multiple RACH opportunities (ROs) are allocated.

[0007] Figure 2 is a timing diagram of an example RACH slot in which multiple RACH opportunities (ROs) are allocated and a set of adjusted ROs are derived in accordance with various disclosed aspects.

[0008] Figure 3 is a timing diagram of an example RACH slot in which multiple ROs are allocated and a set of adjusted ROs are derived in accordance with various disclosed aspects.

[0009] Figure 4 is a timing diagram of an example RACH slot in which multiple ROs are allocated and a set of adjusted ROs are derived in accordance with various disclosed aspects.

[0010] Figure 5 is a flow chart illustrating an example method for performing RACH communication at a UE in accordance with various disclosed aspects.

[0011] Figure 6 is a flow chart illustrating an example method for performing RACH communications at a base station in accordance with various disclosed aspects.

[0012] Figure 7 An exemplary communication network in accordance with various disclosed aspects is shown.

[0013] Figure 8 Examples of base stations (e.g., infrastructure equipment devices, eNBs, gNBs) in accordance with various aspects of the disclosure are shown.

[0014] Figure 9 An example of a user equipment device (eg, UE) in accordance with various aspects of the disclosure is shown. DETAILED DESCRIPTION

[0015] The present disclosure is described with reference to the accompanying drawings. The drawings are not drawn to scale and are provided solely for the purpose of illustrating the present disclosure. Several aspects of the present disclosure are described below with reference to example applications / use cases for illustration. Many specific details, relationships, and methods are set forth to provide an understanding of the present disclosure. The present disclosure is not limited by the order of the actions or events illustrated, as some actions may occur in a different order and / or concurrently with other actions or events. Furthermore, not all illustrated actions or events are necessary to implement a method according to a selected disclosure.

[0016] The channel access mechanism aspect is a fundamental building block for NR-unlicensed. In addition to meeting regulatory requirements, the adoption of Listen Before Talk (LBT) in LAA (License Assisted Access) systems based on LTE (Long Term Evolution) facilitates fair coexistence with neighboring systems sharing the unlicensed spectrum. The LBT-based channel access mechanism is generally similar to the Carrier Sense Multiple Access / Collision Avoidance (CSMA / CA) principle of WLAN. Any node that is expected to transmit in the unlicensed spectrum first performs a channel sensing operation before initiating any transmission. When more than one node senses that the channel is idle and transmits simultaneously, an additional random backoff mechanism can be employed to avoid collisions.

[0017] To meet regulatory requirements and provide a global solution with a unified framework, NR-based unlicensed access will also use a channel access mechanism based on LBT. Due to LBT, the performance of uplink (UL) transmissions (such as preamble transmissions over the physical random access channel (PRACH)) may be affected while operating in the unlicensed spectrum. Before the PRACH preamble can be transmitted, LBT may need to be performed on the user equipment (UE) side. The resource allocation scheme for PRACH in NR licensed systems that does not need to deal with such channel access-related contention may not be sufficient for PRACH preamble transmission in the unlicensed spectrum.

[0018] Described herein are systems, methods, and circuits for adjusting a pre-configured RO (eg, a continuous RO based on a licensed spectrum NR) to address LBT in an unlicensed spectrum.

[0019] Figure 1 A wireless communication network 100 is shown including a base station 111 (eg, a next generation Node B (gNB), an evolved Node B (eNB), etc.) and two user equipment devices 101 (UE). Figure 7 An exemplary wireless communication network is described in more detail. A base station 111 includes circuitry 110 (e.g., a baseband processor or one or more processors) configured to insert time gaps in a set of preconfigured ROs to generate a set of adjusted ROs that facilitate LBT prior to PRACH preamble transmission. A UE 101 includes similar circuitry 110 that also inserts time gaps in a set of preconfigured ROs to generate a set of adjusted ROs that facilitate LBT prior to PRACH preamble transmission. When a base station or UE is described as performing a function or method, it should be understood that it is the circuitry 110 that causes the base station or UE to perform the function or method.

[0020] In NR, the random access preamble is transmitted in the time domain resources given by the higher-layer parameter prach-ConfigurationIndex according to the PRACH configuration table defined in TS 38.211 and depends on the spectrum type (paired / FDD or unpaired / TDD) and frequency range (FR1 or FR2). Figure 1 The base station 111 is shown transmitting the prach-ConfigurationIndex to the UE. However, the UE may have received the prach-ConfigurationIndex based on previous higher layer signaling from different network entities. Each prach-ConfigurationIndex (0, 1, ..., 255) indicates the associated preamble format, system frame number or SFN (n SFN ), subframe number, starting symbol, number of PRACH slots in a subframe, number of time-domain PRACH opportunities in a PRACH slot (N t RA，时隙 ) and PRACH duration They completely define the time domain resource allocation for PRACH.

[0021] like Figure 1 and Figure 1AAs shown, using prach-ConfigurationIndex, a plurality of consecutive or successive RACH opportunities (ROs) within a PRACH slot may be allocated to the UE, from which the UE will select the first available RO for preamble transmission. Figure 1A , RO(0)-RO(2) are allocated to UE(A), and RO(3)-RO(5) are allocated to UE(B).

[0022] In unlicensed spectrum, a UE may need to perform a clear channel assessment (CCA) to sense the medium before accessing (in case the medium is idle) for preamble transmission. If consecutive ROs are assigned to different UEs for preamble transmission, the UE with RO(j) will perform LBT before the start symbol for RO(i) and may be blocked by the preamble transmission of another UE at RO(i-1). Therefore, in the illustrated example, since the LBT for RO(3) overlaps with the preamble transmission of UE(A) in RO(2), UE(B) may be blocked from transmitting PRACH in RO(3). In the following sections, enhancements related to time domain RO configuration are disclosed, which can potentially alleviate inter-UE LBT blocking in NR-unlicensed.

[0023] In one example, a time gap for CCA may be inserted before each RO preconfigured by the prach-ConfigurationIndex in the NR. The inserted time gap may be in units of integer multiples of the OFDM symbol duration, such as n symbol duration, or in units of time, such as mμs, or a combination thereof (e.g., n symbols + mμs), where the symbol duration is defined according to parameters based on the PRACH preamble. Alternatively, for the corresponding PRACH preamble format, the inserted time gap may be in units of integer multiples of the RO duration.

[0024] See also Figure 2 , shows a set of pre-configured ROs (e.g., according to prach-ConfigurationIndex) and a set of adjusted ROs reflecting the time gaps between the pre-configured ROs. The set of pre-configured ROs includes six consecutive or sequential ROs that are adjacent to each other in time. In other examples, the pre-configured ROs may have different quantities or timings.

[0025] Figure 2 shows that by “deactivating” x number of ROs before the i-th RO The set of adjusted ROs is derived from the set of pre-configured ROs by appending a time gap of n symbols (n≥1) at the beginning of the i-th RO within the RACH slot. For example, the (i-1)-th, (i-2), ... (ix)-th ROs may be deactivated, where one RO duration is The time gap may be configured by higher layer signaling (e.g., via prach-ConfigurationIndex) from an enhanced PRACH configuration table (e.g., by adding an additional column to the existing NR PRACH configuration table indicating the LBT gap to derive a valid non-contiguous RO from the predefined continuous RO used in NR). Alternatively, the time gap may be implicitly derived based on other parameters indicated by higher layer signaling (e.g., preamble subcarrier spacing, LBT category used for access channel for preamble transmission, etc.). In this way, the non-contiguously adjusted RO is determined from the PRACH configuration table corresponding to prach-ConfigurationIndex.

[0026] As an example, if the preamble format A1 is configured by the higher layer parameter prach-ConfigurationIndex, there can be 6 ROs in the RACH time slot in NR, with a duration of 2 OFDM symbols / RO. If a time gap of 2 symbols is to be inserted between the ROs, each alternative RO in the group of 6 consecutive ROs in the NR PRACH configuration table can be "deactivated". In other words, if the RO index is RO(0), RO(1), ..., RO(5), then the ROs with odd indices (i.e. RO(1), RO(3), RO(5)) are "deactivated" and the ROs with even indices (i.e. RO(0), RO(2), RO(4)) are used, or vice versa, as shown in FIG. Figure 2 shown.

[0027] In another option, a scaling factor and / or offset can be configured by higher layers as part of the PRACH configuration to indicate that a subset of ROs is deactivated. The scaling factor can be a fractional value, such as 1 / N, where N is a positive integer. For example, when the scaling factor = 1 / 2, this indicates that half of the ROs are deactivated. The offset can indicate the starting RO for deactivation. For example, assuming a scaling factor = 1 / 2, an offset = 1, and PRACH format A1 has 6 ROs in a timeslot, this indicates that RO#1, RO#3, and RO#5 are deactivated.

[0028] See also Figure 3, shows a set of pre-configured ROs (e.g., according to prach-ConfigurationIndex) and a set of adjusted ROs reflecting the time gaps between the pre-configured ROs. The set of pre-configured ROs includes six consecutive or sequential ROs that are adjacent to each other in time. In other examples, the pre-configured ROs may have different quantities or timings.

[0029] Figure 3 It is shown that by configuring an offset of "x" symbols by higher layer signaling, a time gap of n symbols (n>1) is added at the beginning of the i-th RO (i>0) in the RACH slot, and the set of adjusted ROs is derived from the set of pre-configured ROs. The offset is used by the UE (or base station) to implicitly determine the spacing between consecutive ROs in the slot, and thus the RO can be shifted relative to the RO (0) or the first RO in the RACH slot (configured in the PRACH configuration table for NR corresponding to the row index indicated by prach-ConfigurationIndex). If the shifted RO crosses the RACH slot boundary, the RO is not considered a valid RO. If the shifted RO is not within the duration of the original RACH opportunity, the RO is not considered a valid RO.

[0030] As an example, Figure 3 As shown, if the preamble format A1 is configured by the higher layer parameter prach-ConfigurationIndex, there can be 6 ROs in the RACH slot in NR, with a duration of 2 OFDM symbols / RO. If a time gap of 1 symbol is inserted between the ROs, there will be 5 available ROs per RACH slot, where RO(1) to RO(4) are shifted relative to RO(0). The shifted RO(5) crosses the RACH slot boundary and is therefore not considered (e.g., allocated) as a valid RO.

[0031] In the same example, if the last two OFDM symbols need to be empty for other purposes (e.g., UL control channel), there will be 4 available ROs per RACH slot, where RO(1) to RO(3) are shifted relative to R(0). The shifted RO(4) and RO(5) are not within the original duration of the RO and therefore are not considered (e.g., allocated) as valid ROs.

[0032] See also Figure 4, shows a set of preconfigured ROs (e.g., according to rach-ConfigurationIndex) and a set of adjusted ROs reflecting the time gaps between the preconfigured ROs. The set of preconfigured ROs includes six consecutive or sequential ROs that are adjacent to each other in time. In other examples, the preconfigured ROs may have a different number or timing. In the illustrated example, the time gaps between consecutive ROs within a RACH slot may vary.

[0033] For example, two UEs may be configured with consecutive ROs within a RACH slot, such that UE (A) is configured with a 2-step RACH procedure (i.e., preamble (MSG1) and TDM'd PUSCH (MSG3) are transmitted together in a single message), while UE (B) is configured with a 2-step or 4-step RACH procedure (i.e., preamble-only transmission in MSG1 or RO). The first available RO for UE (B) may need to be shifted by n symbols relative to the first available RO for UE (A), while the time gap between consecutive other ROs may be the same for both UEs and may be less than n symbols, e.g. Figure 4 As shown in option 2.

[0034] Alternatively, UE(B) may be allocated the same RO as UE(A), in which case ROs (transmitted by UE(A)) that overlap in time with the message duration will not be available to UE(B) (i.e., LBT for UE(B) will fail on these ROs), as Figure 4 as shown in option 1.

[0035] In another example, a time gap for CCA can be inserted before each RO by inserting a guard period (GP) at the end of the preamble transmission (e.g., for formats A1, A2, A3) or extending the guard period (e.g., for format B or format C), so that the GP of the preamble transmitted in RO(i-1) can be combined with the LBT gap for the preamble scheduled in RO(i).

[0036] In another example, time gaps can be created between consecutive ROs by puncturing / truncating one or more repeated preamble transmissions within the RO. As an example, preamble format B1 has a time domain structure of cyclic prefix (CP) + sequence + sequence + GP. To create time gaps between ROs, the last sequence transmission can be punctured so that the gap (CP + sequence + GP) can be used for LBT / CCA. If a longer CCA gap is required (depending on the LBT category, priority level, and contention window size), an additional time gap can also be configured on top of the puncturing.

[0037] Below are several flow charts outlining example methods. In this specification and the appended claims, the use of the term "determine" when describing method steps or functions with reference to some entities (e.g., parameters, variables, etc.) is to be interpreted broadly. For example, "determine" is to be interpreted as covering communications such as receiving and parsing an encoded entity or value of an entity. "Determine" should be interpreted as covering accessing and reading a memory (e.g., a lookup table, register, device memory, remote memory, etc.) that stores an entity or value for an entity. "Determine" should be interpreted as covering calculating or deriving an entity or value of an entity based on other quantities or entities. "Determine" should be interpreted as covering any way of inferring or identifying an entity or value of an entity.

[0038] As used herein, the term "identify," when used with reference to an entity or a value of an entity, is to be broadly interpreted to encompass any manner of determining an entity or a value of an entity. For example, the term "identify" is to be interpreted to encompass, for example, receiving and parsing communications encoding an entity or a value of an entity. The term "identify" should be interpreted to encompass accessing and reading a memory (e.g., a device queue, a lookup table, a register, a device memory, a remote memory, etc.) storing an entity or a value for an entity.

[0039] As used herein, the term "select" when used with reference to an entity or value of an entity is to be interpreted broadly to encompass any way of determining an entity or a value of an entity from a plurality or a range of possible choices. For example, the term "select" is to be interpreted as encompassing accessing and reading a memory (e.g., a lookup table, register, device memory, remote memory, etc.) that stores entities or values for entities and returning an entity or entity value from those stored. The term "select" is to be interpreted as applying one or more constraints or rules to a set of input parameters to determine an appropriate entity or entity value. The term "select" is to be interpreted broadly to encompass any way of selecting an entity based on one or more parameters or conditions.

[0040] As used herein, the term "derive" is to be interpreted broadly when used with reference to an entity or a value of an entity. "Deriving" should be interpreted to encompass accessing and reading a memory (e.g., a lookup table, registers, device memory, remote memory, etc.) that stores some initial or base values, and performing processing and / or logical / mathematical operations on one or more values to generate a derived entity or value for an entity. "Deriving" should be interpreted to encompass calculating or measuring an entity or a value for an entity based on other quantities or entities. "Deriving" should be interpreted to encompass any way of inferring or identifying an entity or a value for an entity.

[0041] Figure 5A flow chart outlining a method 500 for performing RACH communication at a UE is depicted. The method includes, at 510, determining a set of preconfigured ROs, wherein the set of preconfigured ROs includes a plurality of consecutive ROs. The method includes, at 520, deriving a set of adjusted ROs by inserting time gaps between ROs in the set of preconfigured ROs. The method includes, at 530, transmitting a physical random access channel (PRACH) preamble in at least one adjusted RO in the set of adjusted ROs.

[0042] Figure 6 A flow chart outlining a method 600 for performing RACH communication at a base station is depicted. The method includes, at 610, determining a set of preconfigured ROs, wherein the set of preconfigured ROs includes a plurality of consecutive ROs. The method includes, at 620, deriving a set of adjusted ROs by inserting time gaps between ROs in the set of preconfigured ROs. The method includes, at 630, receiving a physical random access channel (PRACH) preamble in at least one adjusted RO in the set of adjusted ROs.

[0043] Figure 7 An exemplary architecture of a system 700 of a communication network according to various embodiments is shown. The following description is provided for an exemplary system 700 operating in conjunction with LTE system standards and 5G or NR system standards provided by 3GPP technical specifications. However, the exemplary embodiments are not limited in this regard and may be applied to other networks that benefit from the principles described herein, such as future 3GPP systems (e.g., sixth generation (6G) systems), IEEE 802.16 protocols (e.g., WMAN, WiMAX, etc.), and the like.

[0044] like Figure 7As shown, system 700 includes UE 701a and UE 701b (collectively referred to as "UE 701"). In this example, UE 701 is shown as a smart phone (e.g., a handheld touch screen mobile computing device that can connect to one or more cellular networks), but it can also include any mobile or non-mobile computing device, such as a consumer electronic device, a mobile phone, a smart phone, a feature phone, a tablet computer, a wearable computer device, a personal digital assistant (PDA), a pager, a wireless handheld device, a desktop computer, a laptop computer, an in-vehicle infotainment (IVI), an in-car entertainment (ICE) device, an instrument panel (IC), a head-up display (HUD) device, an on-board diagnostic (OBD) device, a dashtop mobile device (DME), a mobile data terminal (MDT), an electronic engine management system (EEMS), an electronic / engine electronic control unit (ECU), an electronic / engine electronic control module (ECM), an embedded system, a microcontroller, a control module, an engine management system (EMS), a connected or "smart" appliance, a MTC device, an M2M device, an IoT device, etc.

[0045] In some embodiments, any of the UEs 701 may be an IoT UE, which may include a network access layer designed for low-power IoT applications that utilize short-term UE connections. The IoT UE may utilize technologies such as M2M or MTC to exchange data with an MTC server or device via a PLMN, ProSe or D2D communications, a sensor network, or an IoT network. M2M or MTC data exchanges may be machine-initiated data exchanges. The IoT network describes interconnected IoT UEs, which may include uniquely identifiable embedded computing devices (within the Internet infrastructure) with short-term connections. The IoT UE may execute background applications (e.g., keep-alive messages, status updates, etc.) to facilitate connectivity to the IoT network.

[0046] UE 701 may be configured to connect, e.g., be communicatively coupled to, a RAN 710. In an embodiment, RAN 710 may be an NG RAN or 5G RAN, E-UTRAN, or a legacy RAN, such as UTRAN or GERAN. As used herein, the term "NGRAN," etc., may refer to a RAN 710 operating in an NR or 5G system 700, while the term "E-UTRAN," etc., may refer to a RAN 710 operating in an LTE or 4G system 700. Multiple UEs 701 utilize connections (or channels) 703 and 704, respectively, each connection comprising a physical communication interface or layer (discussed in further detail below).

[0047] In this example, connections 703 and 704 are shown as air interfaces to achieve communication coupling and may be consistent with a cellular communication protocol, such as a GSM protocol, a CDMA network protocol, a PTT protocol, a POC protocol, a UMTS protocol, a 3GPP LTE protocol, a 5G protocol, a NR protocol, and / or any other communication protocol discussed herein. In an embodiment, multiple UEs 701 may directly exchange communication data via a ProSe interface 705. The ProSe interface 705 may alternatively be referred to as an SL interface 705 and may include one or more logical channels, including but not limited to a PSCCH, a PSSCH, a PSDCH, and a PSBCH.

[0048] UE 701b is shown as being configured to access AP 706 (also referred to as "WLAN node 706," "WLAN 706," "WLAN terminal 706," "WT 706," etc.) via connection 707. Connection 707 may comprise a local wireless connection, such as a connection consistent with any IEEE 802.11 protocol, wherein AP 706 would include Wireless Fidelity. router. In this example, AP 706 is shown connected to the Internet without being connected to the core network of the wireless system (described in further detail below). In various embodiments, UE 701b, RAN 710, and AP 706 can be configured to utilize LWA operation and / or LWIP operation. LWA operation can involve UE 701b in RRC CONNECTED being configured by RAN nodes 711a-711b to utilize radio resources of LTE and WLAN. LWIP operation can involve UE 701b using WLAN radio resources (e.g., connection 707) via an IPsec protocol tunnel to authenticate and encrypt packets (e.g., IP packets) sent over connection 707. IPsec tunneling can include encapsulating the entire original IP packet and adding a new packet header, thereby protecting the original header of the IP packet.

[0049] The RAN 710 may include one or more AN nodes or RAN nodes 711a and 711b (collectively referred to as "RAN nodes 711") that enable connections 703 and 704. As used herein, the terms "access node," "access point," and the like may describe equipment that provides radio baseband functionality for data and / or voice connections between a network and one or more users. These access nodes may be referred to as BSs, gNBs, RAN nodes, eNBs, NodeBs, RSUs, TRxPs, or TRPs, and may include ground stations (e.g., terrestrial access points) or satellite stations that provide coverage within a geographic area (e.g., a cell). As used herein, the terms "NG RAN nodes" and the like may refer to RAN nodes 711 (e.g., gNBs) operating in NR or 5G systems 700, while the terms "E-UTRAN nodes" and the like may refer to RAN nodes 711 (e.g., eNBs) operating in LTE or 4G systems 700. According to various embodiments, the RAN node 711 may be implemented as one or more dedicated physical devices such as a macrocell base station and / or a low power (LP) base station for providing a femtocell, picocell or other similar cell with a smaller coverage area, smaller user capacity or higher bandwidth than a macrocell.

[0050] According to various embodiments, the UE 701 and the RAN node 711 communicate data (e.g., transmit data and receive data) via a licensed medium (also referred to as a "licensed spectrum" and / or a "licensed band") and an unlicensed shared medium (also referred to as an "unlicensed spectrum" and / or an "unlicensed band"). The licensed spectrum may include channels operating in a frequency range of approximately 400 MHz to approximately 3.8 GHz, while the unlicensed spectrum may include a 5 GHz band.

[0051] To operate in the unlicensed spectrum, the UE 701 and the RAN node 711 may operate using LAA, eLAA, and / or feLAA mechanisms. In these implementations, the UE 701 and the RAN node 711 may perform one or more known medium sensing operations and / or carrier sensing operations to determine whether one or more channels in the unlicensed spectrum are unavailable or otherwise occupied before transmitting in the unlicensed spectrum. The medium / carrier sensing operations may be performed according to a listen-before-talk (LBT) protocol.

[0052] LBT is a mechanism whereby equipment (e.g., UE 701 RAN node 711, etc.) utilizes the mechanism to sense the medium (e.g., a channel or carrier frequency) and transmit when the medium is sensed to be idle (or when a particular channel in the medium is sensed to be unoccupied). The medium sensing operation may include CCA, which utilizes at least ED to determine whether other signals are present on the channel in order to determine whether the channel is occupied or idle. The LBT mechanism allows cellular / LAA networks to coexist with existing systems in unlicensed spectrum and with other LAA networks. ED may include sensing RF energy on the intended transmission band over a period of time and comparing the sensed RF energy to a predefined or configured threshold.

[0053] Typically, existing systems in the 5 GHz band are WLANs based on IEEE 802.11 technology. WLANs employ a contention-based channel access mechanism known as CSMA / CA. Here, when a WLAN node (e.g., a mobile station (MS) such as UE 701, AP 706, etc.) intends to transmit, the WLAN node may first perform CCA before transmitting. In addition, in the event that more than one WLAN node senses the channel as idle and transmits simultaneously, a backoff mechanism is used to avoid collisions. The backoff mechanism may be a counter randomly introduced within the CWS that increases exponentially when a collision occurs and is reset to a minimum value when the transmission is successful. The LBT mechanism designed for LAA is somewhat similar to CSMA CA for WLAN. In some implementations, the LBT process for a DL or UL transmission burst (including PDSCH or PUSCH transmission) may have an LAA contention window of variable length between X and Y ECCA slots, where X and Y are the minimum and maximum values of the CWS for LAA. In one example, the minimum CWS for LAA transmissions may be 9 microseconds (μs); however, the size of the CWS and MCOT (eg, transmission burst) may be based on government regulatory requirements.

[0054] The LAA mechanism is built on the Carrier Adaptation (CA) technology of the LTE-Advanced system. In CA, each aggregated carrier is called a CC. A CC can have a bandwidth of 1.4, 3, 5, 10, 15, or 20 MHz, and up to five CCs can be aggregated, resulting in a maximum aggregate bandwidth of 100 MHz. In an FDD system, the number of aggregated carriers can be different for DL and UL, where the number of UL CCs is equal to or lower than the number of DL component carriers. In some cases, each CC can have a different bandwidth than other CCs. In a TDD system, the number of CCs and the bandwidth of each CC are generally the same for DL and UL.

[0055] CA also includes individual serving cells to provide individual CCs. The coverage of the serving cells may be different, for example, because CCs on different frequency bands will experience different path losses. The primary serving cell or PCell may provide the PCC for both UL and DL and may handle activities related to RRC and NAS. The other serving cells are called SCells, and each SCell may provide individual SCCs for both UL and DL. SCCs may be added and removed as needed, and changing the PCC may require the UE 701 to undergo a handover. In LAA, eLAA, and feLAA, some or all of the SCells may operate in unlicensed spectrum (referred to as "LAA SCells"), and the LAA SCells are assisted by the PCells operating in the licensed spectrum. When a UE is configured with more than one LAA SCell, the UE may receive UL grants on the configured LAA SCells indicating different PUSCH starting positions within the same subframe.

[0056] The PDSCH carries user data and higher-layer signaling to the UE 701. The PDCCH carries, among other information, information about the transport format and resource allocation associated with the PDSCH channel. It can also inform multiple UEs 701 about the transport format, resource allocation, and HARQ information associated with the uplink shared channel. Typically, downlink scheduling (allocation of control and shared channel resource blocks to UEs 701b within a cell) can be performed at any of the RAN nodes 711 based on channel quality information fed back from any of the UEs 701. Downlink resource allocation information can be sent on the PDCCH for (e.g., allocated to) each of the multiple UEs 701.

[0057] RAN 710 is shown as being communicatively coupled to a core network—in this embodiment, to a core network (CN) 720. CN 720 may include multiple network elements 722 configured to provide various data and telecommunication services to customers / users (e.g., users of UE 701) connected to CN 720 via RAN 710. Components of CN 720 may be implemented in one physical node or separate physical nodes, including components for reading and executing instructions from machine-readable or computer-readable media (e.g., non-transitory machine-readable storage media). In some embodiments, NFV may be used to virtualize any or all of the aforementioned network node functions (described in further detail below) via executable instructions stored on one or more computer-readable storage media. A logical instance of CN 720 may be referred to as a network slice, and a logical instance of a portion of CN 720 may be referred to as a network sub-slice. NFV architecture and infrastructure may be used to virtualize one or more network functions onto physical resources comprising a combination of industry-standard server hardware, storage hardware, or switches (alternatively, performed by proprietary hardware). In other words, the NFV system can be used to perform virtual or reconfigurable implementations of one or more EPC components / functions.

[0058] Figure 8 An example of infrastructure equipment 800 according to various embodiments is shown. Infrastructure equipment 800 (or "system 800") can be implemented as a base station, a radio head, a RAN node (such as the RAN node 711 and / or AP 706 shown and described previously), an application server 730, and / or any other element / device discussed herein. In other examples, system 800 can be implemented in or by a UE.

[0059] System 800 includes application circuitry 805, baseband circuitry 810, one or more radio front-end modules (RFEMs) 815, memory circuitry 820, a power management integrated circuit (PMIC) 825, power tee circuitry 830, network controller circuitry 835, a network interface connector 840, satellite positioning circuitry 845, and a user interface 850. In some embodiments, device 800 may include additional components such as, for example, memory / storage, a display, a camera, sensors, or input / output (I / O) interfaces. In other embodiments, these components may be included in more than one device. For example, the circuitry may be separately included in more than one device for a CRAN, vBBU, or other similar implementation.

[0060] The application circuit 805 may include circuits such as, but not limited to, one or more processors (or processor cores), cache memory, and one or more of the following: a low dropout regulator (LDO), an interrupt controller, a serial interface such as SPI, I2C, or a general-purpose programmable serial interface module, a real-time clock (RTC), a timer-counter (including an interval timer and a watchdog timer), general-purpose input / output (I / O or IO), a memory card controller such as a secure digital (SD) multimedia card (MMC) or similar product, a universal serial bus (USB) interface, a mobile industry processor interface (MIPI) interface, and a joint test access group (JTAG) test access port. The processor (or core) of the application circuit 805 may be coupled to or include a memory / storage element and may be configured to execute instructions stored in the memory / storage element to enable various applications or operating systems to run on the system 800. In some implementations, the memory / storage element can be an on-chip memory circuit that can include any suitable volatile and / or non-volatile memory, such as DRAM, SRAM, EPROM, EEPROM, flash memory, solid-state memory, and / or any other type of memory device technology, such as those discussed herein.

[0061] The processor of the application circuit 805 may include, for example, one or more processor cores (CPUs), one or more application processors, one or more graphics processing units (GPUs), one or more reduced instruction set computing (RISC) processors, one or more Acorn RISC Machine (ARM) processors, one or more complex instruction set computing (CISC) processors, one or more digital signal processors (DSPs), one or more FPGAs, one or more PLDs, one or more ASICs, one or more microprocessors or controllers, or any suitable combination thereof. In some embodiments, the application circuit 805 may include or may be a dedicated processor / controller for operating in accordance with various embodiments herein. As an example, the processor of the application circuit 805 may include one or more processor, Processor; Advanced Micro Devices (AMD) Processor, Accelerated Processing Unit (APU), or processors; ARM Holdings, Ltd. licensed ARM-based processors, such as the ARM Cortex-A series processors provided by Cavium (TM), Inc. and MIPS-based designs from MIPS Technologies, Inc., such as the MIPS Warrior P-class processor; etc. In some embodiments, the system 800 may not utilize application circuitry 805 and instead may include a dedicated processor / controller to process IP data received, for example, from an EPC or 5GC.

[0062] The user interface circuitry 850 may include one or more user interfaces designed to enable a user to interact with the system 800 or a peripheral component interface designed to enable a peripheral component to interact with the system 800. The user interface may include, but is not limited to, one or more physical or virtual buttons (e.g., a reset button), one or more indicators (e.g., light emitting diodes (LEDs)), a physical keyboard or keypad, a mouse, a touchpad, a touch screen, a speaker or other audio emitting device, a microphone, a printer, a scanner, a headset, a display screen or display device, etc. The peripheral component interface may include, but is not limited to, a non-volatile memory port, a universal serial bus (USB) port, an audio jack, a power port, etc.

[0063] Figure 8 The components shown can communicate with each other using interface circuitry that can include any number of bus and / or interconnect (IX) technologies, such as Industry Standard Architecture (ISA), Extended ISA (EISA), Peripheral Component Interconnect (PCI), Peripheral Component Interconnect Extended (PCIx), PCI express (PCIe), or any number of other technologies. The bus / IX can be a proprietary bus, such as used in SoC-based systems. Other bus / IX systems can be included, such as an I2C interface, an SPI interface, a point-to-point interface, and a power bus, among others.

[0064] Figure 9 An example of a platform 900 (or "device 900") according to various embodiments is shown. In an embodiment, the computer platform 900 may be suitable for use as a UE 101, 701, an application server 730, and / or any other element / device discussed herein. The platform 900 may include any combination of the components shown in the example. The components of the platform 900 may be implemented as integrated circuits (ICs), portions of ICs, discrete electronic devices, or other modules, logic, hardware, software, firmware, or combinations thereof adapted within the computer platform 900, or as components otherwise incorporated within the chassis of a larger system. Figure 9 The block diagram is intended to show a high-level view of the components of computer platform 900. However, some of the components shown may be omitted, additional components may be present, and different arrangements of the components shown may occur in other implementations.

[0065] The application circuit 905 includes circuitry such as, but not limited to, one or more processors (or processor cores), cache memory, and one or more of an LDO, an interrupt controller, a serial interface (such as SPI), I2C or a general-purpose programmable serial interface module, an RTC, a timer-counter (including an interval timer and a watchdog timer), general-purpose I / O, a memory card controller (such as an SDMMC or similar controller), a USB interface, a MIPI interface, and a JTAG test access port. The processor (or core) of the application circuit 905 may be coupled to or include a memory / storage element and may be configured to execute instructions stored in the memory / storage element to enable various applications or operating systems to run on the system 900. In some implementations, the memory / storage element may be an on-chip memory circuit that may include any suitable volatile and / or non-volatile memory, such as DRAM, SRAM, EPROM, EEPROM, flash memory, solid-state memory, and / or any other type of memory device technology, such as those discussed herein.

[0066] For example, the processor of application circuit 905 may include a general-purpose or special-purpose processor, such as a commercially available processor. Inc., Cupertino, CA A series processor (e.g., A13 Bionic) or any other such processor. The processor of the application circuit 905 may also be one or more of the following: Advanced Micro Devices (AMD) Processor or Accelerated Processing Unit (APU); from Inc.'s core processors, Snapdragon by Technologies, Inc. TM processors, Texas Instruments, Open Multimedia ApplicationsPlatform(OMAP) TM processors; MIPS-based designs from MIPS Technologies, Inc., such as the MIPS Warrior-class, Warrior I-class, and Warrior P-class processors; ARM-based designs licensed from ARM Holdings, Ltd., such as the ARM Cortex-A, Cortex-R, and Cortex-M series processors; etc. In some implementations, the application circuit 905 can be part of a system on a chip (SoC), in which the application circuit 905 and other components are formed as a single integrated circuit or a single package.

[0067] Baseband circuit 910 may be implemented, for example, as a solder-in substrate including one or more integrated circuits, a single packaged integrated circuit soldered to a main circuit board, or a multi-chip module containing two or more integrated circuits.

[0068] The platform 900 may also include an interface circuit (not shown) for connecting external devices to the platform 900. External devices connected to the platform 900 via the interface circuit include a sensor circuit 921 and an electromechanical component (EMC) 922, and a removable memory device coupled to a removable memory circuit 923.

[0069] Battery 930 can power platform 900, but in some examples, platform 900 can be installed in a fixed location and can have a power source coupled to the power grid. Battery 930 can be a lithium-ion battery, a metal-air battery such as a zinc-air battery, an aluminum-air battery, a lithium-air battery, etc. In some implementations, such as in V2X applications, battery 930 can be a typical lead-acid automobile battery.

[0070] Although the method is shown and described as a series of actions or events above, it should be understood that the order of such actions or events shown should not be interpreted as having a limiting meaning. For example, some actions can occur in different orders and / or simultaneously with other actions or events other than those shown and / or described herein. In addition, it may not be necessary for all the actions shown to implement one or more aspects or embodiments disclosed herein. In addition, one or more actions in the actions shown herein can be performed in one or more separate actions and / or stages. In some embodiments, the method shown above can be implemented in a computer-readable medium using instructions stored in a memory. Many other embodiments and variations are possible within the scope of the present disclosure protected by the claims.

[0071] Example

[0072] Embodiment 1 is an apparatus for a user equipment (UE), comprising one or more processors configured to cause the UE to: determine a set of preconfigured random access channel (RACH) opportunities (ROs), wherein the set of preconfigured ROs comprises a plurality of consecutive ROs; derive a set of adjusted ROs by inserting time gaps between ROs in the set of preconfigured ROs; and transmit a physical random access channel (PRACH) preamble in at least one adjusted RO in the set of adjusted ROs.

[0073] Embodiment 2 includes the subject matter of embodiment 1, including or omitting optional elements, wherein the one or more processors are configured to cause the UE to derive the set of adjusted ROs by inserting a time gap of a predetermined duration between one or more consecutive ROs in the set of preconfigured ROs.

[0074] Embodiment 3 includes the subject matter of embodiment 2, including or omitting optional elements, wherein the predetermined duration includes a predetermined number of symbols.

[0075] Embodiment 4 includes the subject matter of embodiment 2, including or omitting optional elements, wherein the predetermined duration includes a predetermined time duration.

[0076] Embodiment 5 includes the subject matter of embodiment 2, including or omitting optional elements, wherein the predetermined duration comprises a predetermined integer multiple of the RO duration.

[0077] Embodiment 6 includes the subject matter of embodiment 1 including or omitting optional elements, wherein the one or more processors are configured to cause the UE to derive the set of adjusted ROs by deactivating one or more ROs in the set of pre-configured ROs.

[0078] Embodiment 7 includes the subject matter of embodiment 1 including or omitting optional elements, wherein the one or more processors are configured to cause the UE to derive the set of adjusted ROs by inserting or extending a guard period of a PRACH preamble.

[0079] Embodiment 8 includes the subject matter of embodiment 1 including or omitting optional elements, wherein the one or more processors are configured to cause the UE to derive the set of adjusted ROs by puncturing a repetitive sequence of a PRACH preamble.

[0080] Embodiment 9 includes the subject matter of any one of embodiments 1 to 8, including or omitting optional elements, wherein the one or more processors are configured to cause the UE to derive the set of adjusted ROs based on a listen-before-talk (LBT) parameter received in higher layer signaling.

[0081] Embodiment 10 includes the subject matter of any one of embodiments 1 to 8, including or omitting optional elements, wherein the one or more processors are configured to cause the UE to implicitly derive the set of adjusted ROs based on one or more parameters received in higher layer signaling.

[0082] Embodiment 11 includes the subject matter of any one of embodiments 1 to 8, including or omitting optional elements, wherein the one or more processors are configured to cause the UE to determine an invalid RO in the set of adjusted ROs that occurs outside of a predetermined RACH time slot.

[0083] Embodiment 12 includes the subject matter of any one of embodiments 1 to 8, including or omitting optional elements, wherein the one or more processors are configured to cause the UE to shift a first RO in the set of adjusted ROs by a shift offset based on a length of expected PRACH transmissions of different UEs.

[0084] Embodiment 13 includes the subject matter of any one of embodiments 1 to 8, including or omitting optional elements, wherein the one or more processors are configured to cause the UE to perform an LBT procedure before transmitting a PRACH preamble.

[0085] Embodiment 14 is a method, comprising, at a user equipment (UE): determining a set of preconfigured random access channel (RACH) opportunities (ROs), wherein the set of preconfigured ROs comprises a plurality of consecutive ROs; deriving a set of adjusted ROs by inserting time gaps between ROs in the set of preconfigured ROs; and transmitting a physical random access channel (PRACH) preamble in at least one adjusted RO in the set of adjusted ROs.

[0086] Embodiment 15 includes the subject matter of embodiment 14, including or omitting optional elements, including deriving the set of adjusted ROs by inserting a time gap of predetermined duration between one or more consecutive ROs in the set of preconfigured ROs.

[0087] Embodiment 16 includes the subject matter of embodiment 14, including or omitting optional elements, including deriving the set of adjusted ROs by deactivating one or more ROs in the set of pre-configured ROs.

[0088] Embodiment 17 includes the subject matter of embodiment 14, including or omitting optional elements, including deriving the set of adjusted ROs by modifying a PRACH preamble.

[0089] Embodiment 18 includes the subject matter of any one of Embodiments 14 to 17, including or omitting optional elements, including deriving the set of adjusted ROs based on one or more parameters received in higher layer signaling.

[0090] Embodiment 19 includes the subject matter of any one of Embodiments 14 to 17, including or omitting optional elements, comprising shifting a first RO in the set of adjusted ROs by a shift offset based on a length of expected PRACH transmissions for different UEs.

[0091] Embodiment 20 is a method, comprising, at a base station: determining a set of preconfigured random access channel (RACH) opportunities (ROs), wherein the set of preconfigured ROs comprises a plurality of consecutive ROs; deriving a set of adjusted ROs by inserting time gaps between ROs in the set of preconfigured ROs; and receiving a physical random access channel (PRACH) preamble in at least one adjusted RO in the set of adjusted ROs.

[0092] Embodiment 21 includes the subject matter of embodiment 20, including or omitting optional elements, including deriving the set of adjusted ROs by inserting a time gap of predetermined duration between one or more consecutive ROs in the set of preconfigured ROs.

[0093] Embodiment 22 includes the subject matter of embodiment 20, including or omitting optional elements, including deriving the set of adjusted ROs by deactivating one or more ROs in the set of pre-configured ROs.

[0094] Embodiment 23 includes the subject matter of embodiment 20, including or omitting optional elements, including deriving the set of adjusted ROs by modifying a PRACH preamble.

[0095] Embodiment 24 includes the subject matter of any one of Embodiments 20 to 23, including or omitting optional elements, comprising shifting a first RO in the set of adjusted ROs by a shift offset based on a length of an expected PRACH transmission by the UE.

[0096] The term "coupled" is used throughout this specification. This term encompasses any connection, communication, or signal path that enables a functional relationship consistent with the description of this disclosure. For example, if device A generates a signal to control device B to perform an action, then in the first example, device A is coupled to device B. Alternatively, in the second example, if the intermediate component C does not substantially change the functional relationship between devices A and B such that device B is controlled by device A via the control signal generated by the devices, then device A is coupled to device B via the intermediate component C.

[0097] It is understood that the use of personally identifiable information should be subject to privacy policies and practices that are generally recognized to meet or exceed industry or government requirements for maintaining user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of authorized use should be clearly stated to users.

Claims

1. A user equipment (UE), comprising a memory and one or more processors, wherein the one or more processors are configured to, when executing instructions stored in the memory, cause the UE to: receiving a configuration of a set of preconfigured random access channel (RACH) opportunities (ROs), wherein the configuration indicates a plurality of consecutive ROs and information for deriving a time gap; as well as When operating in the unlicensed spectrum, determining the time gap based on the configuration; deriving a set of adjusted ROs by inserting the time gaps between ROs in the plurality of consecutive ROs; shifting a first RO in the set of adjusted ROs by a shift offset based on a length of an expected PRACH transmission for a different UE; as well as A Physical Random Access Channel (PRACH) preamble is transmitted in at least one adjusted RO in the set of adjusted ROs.

2. The UE of claim 1, wherein the one or more processors are configured to cause the UE to derive the set of adjusted ROs by inserting a time gap having a predetermined duration between one or more consecutive ROs of the plurality of consecutive ROs. The UE according to claim 2 , wherein the time gap comprises a predetermined number of symbols or a predetermined duration.

4. The UE of claim 1 , wherein the configuration comprises higher layer signaling of a prach-ConfigurationIndex value indicating one of a plurality of PRACH configurations, wherein the plurality of PRACH configurations include respective indications of the time gap.

5. The UE of claim 1 , wherein the configuration comprises higher layer signaling of a prach-ConfigurationIndex value indicating one of a plurality of PRACH configurations, wherein the plurality of PRACH configurations comprise respective indications of scaling factors indicating a number of ROs to be deactivated, and wherein the one or more processors are configured to cause the UE to derive the set of adjusted ROs by deactivating one or more ROs of the plurality of consecutive ROs based on the scaling factors. 6 . The UE of claim 1 , wherein the one or more processors are configured to cause the UE to implicitly derive the set of adjusted ROs based on information for deriving time gaps without receiving further configuration of the ROs. 7 . The UE of claim 1 , wherein the one or more processors are configured to cause the UE to determine an RO in the set of adjusted ROs that occurs outside a predetermined RACH time slot as an invalid RO.

8. The UE of claim 1, wherein the one or more processors are configured to cause the UE to perform an LBT procedure before initiating transmission of the PRACH preamble.

9. A computing device comprising a baseband processor, the baseband processor being configured to, when executing instructions stored in a memory, perform operations comprising: receiving a configuration of a set of preconfigured random access channel (RACH) opportunities (ROs), wherein the configuration indicates a plurality of consecutive ROs and information for deriving a time gap; as well as When operating in the unlicensed spectrum, determining the time gap based on the configuration; deriving a set of adjusted ROs by inserting the time gaps between ROs in the plurality of consecutive ROs; shifting a first RO in the set of adjusted ROs by a shift offset based on a length of an expected PRACH transmission for a different UE; as well as Transmission of a Physical Random Access Channel (PRACH) preamble is caused in at least one adjusted RO in the set of adjusted ROs.

10. The computing device of claim 9, wherein the operations comprise deriving the set of adjusted ROs by inserting a time gap having a predetermined duration between one or more consecutive ROs of the plurality of consecutive ROs.

11. The computing device of claim 9 , wherein the configuration comprises higher layer signaling of a prach-ConfigurationIndex value indicating one of a plurality of PRACH configurations, wherein the plurality of PRACH configurations include respective indications of scaling factors indicating a number of ROs to be deactivated, and wherein the operation comprises deriving the set of adjusted ROs by deactivating one or more ROs of the plurality of consecutive ROs based on the scaling factors.

12. The computing device of claim 9, wherein the configuration comprises higher layer signaling of a prach-ConfigurationIndex value indicating one of a plurality of PRACH configurations, wherein the plurality of PRACH configurations include respective indications of the time slot.

13. The computing device of claim 9, wherein the operations comprise deriving the set of adjusted ROs based on information used to derive time gaps without receiving further configuration of the ROs.

14. A base station comprising a baseband processor, the baseband processor being configured to perform operations comprising: deriving a set of adjusted Random Access Channel (RACH) preambles for receiving a Physical Random Access Channel (PRACH) preamble from a user equipment (UE) based on a configuration of a set of preconfigured Random Access Channel (RACH) occasions (ROs) for the UE, wherein the configuration indicates a plurality of consecutive ROs and information for deriving a time gap; as well as When the UE operates in an unlicensed spectrum, shifting a first RO in the set of adjusted ROs by a shift offset based on a length of an expected PRACH transmission of a different UE, A Physical Random Access Channel (PRACH) preamble is received in at least one adjusted RO in the set of adjusted ROs.

15. The base station of claim 14, wherein the operations comprise deriving the set of adjusted ROs by inserting a time gap having a predetermined duration between one or more consecutive ROs of the plurality of consecutive ROs.

16. The base station of claim 14 , wherein the configuration comprises higher layer signaling of a prach-ConfigurationIndex value indicating one of a plurality of PRACH configurations, wherein the plurality of PRACH configurations comprise respective indications of scaling factors indicating a number of ROs to be deactivated, and wherein the operation comprises deriving the set of adjusted ROs by deactivating one or more ROs of the plurality of consecutive ROs based on the scaling factors.

17. The base station of claim 14, wherein the configuration comprises higher layer signaling of a prach-ConfigurationIndex value indicating one of a plurality of PRACH configurations, wherein the plurality of PRACH configurations include respective indications of the time slot.

Images