Signaling Method for New Radio in Unlicensed Spectrum

Abstract

Example embodiments relate to signaling between a user equipment (UE) and a cell over unlicensed spectrum. The UE may receive a signal broadcast by a cell of the network over a channel in the unlicensed spectrum. The signal includes a set of channel state information reference signals (CSI-RS), each of which corresponds to a synchronization signal block (SSB) set and is transmitted during a discovery reference signal (DRS) window. The UE may then determine the position of the CSI-RS set within the DRS window and perform operations based on the CSI-RS set.

Description

Background Art

[0001] A user equipment (UE) may establish a connection with at least one of a plurality of different networks or network types. In some networks, signaling between the UE and cells of the network may be performed over an unlicensed spectrum. The unlicensed spectrum is shared by different devices using different communication protocols. Therefore, access to the unlicensed spectrum may involve various regulations and / or standards. For example, listen before talk (LBT) may be implemented in accordance with these regulations and / or standards to access the unlicensed spectrum for communication. LBT as a whole involves determining whether a channel in the unlicensed spectrum is occupied by other signals before performing a transmission through the channel. If LBT fails, the channel is deemed to be busy and no transmission may be performed. If LBT is successful, the channel is deemed to be idle and a transmission may be performed.

[0002] For New Radio (NR-U) in unlicensed spectrum, the way in which conventional channel state information reference signal (CSI-RS) signaling methods consider the failure of listen-before-talk (LBT) has been identified as a source of inefficiency. From a network perspective, conventional methods increase signaling overhead. From a UE perspective, conventional methods include a blind search for CSI-RS by the UE. This causes the UE to experience power consumption. Therefore, there is a need to improve the resource efficiency of CSI-RS transmission in NR-U.

[0003] Furthermore, in NR-U, LBT failures can cause delays during the Physical Random Access Channel (PRACH) procedure. The way conventional PRACH procedures account for LBT failures has also been identified as a cause of unnecessary delays and inefficiencies. For example, conventional approaches increase signaling overhead and can lead to underutilization of uplink resources. Therefore, there is a need to improve the PRACH procedure in NR-U. Summary of the Invention

[0004] According to an exemplary embodiment, a computer-readable storage medium includes a set of instructions that, when executed by a processor of a user equipment (UE), causes the processor to perform operations. These operations include receiving a signal broadcast by a cell of a network over a channel in an unlicensed spectrum. The signal includes a set of channel state information reference signals (CSI-RS), each CSI-RS set corresponding to a synchronization signal block (SSB) set and transmitted during a discovery reference signal (DRS) window. These operations also include determining a position of the CSI-RS set within the DRS window and performing operations based on the CSI-RS set.

[0005] Another exemplary embodiment includes a transceiver configured to communicate with a network and a processor configured to perform operations. The operations include receiving a signal broadcast by a cell of the network over a channel in an unlicensed spectrum. The signal includes a set of channel state information reference signals (CSI-RS), each CSI-RS set corresponding to a synchronization signal block (SSB) set and transmitted during a discovery reference signal (DRS) window. The operations also include determining a position of the CSI-RS set within the DRS window and performing operations based on the CSI-RS set. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 Exemplary network arrangements are shown according to various exemplary embodiments.

[0007] Figure 2 An exemplary UE according to various exemplary embodiments is shown.

[0008] Figure 3 Methods for channel state information reference signal (CSI-RS) reception according to various exemplary embodiments are shown.

[0009] Figure 4 Examples of exemplary channel state information reference signal (CSI-RS) placement within a discovery reference signal (DRS) window are shown in accordance with various exemplary embodiments.

[0010] Figure 5 A table showing non-zero power channel state information reference signal (NZP-CSI-RS) configurations is shown.

[0011] Figures 6a to 6b Examples of NZP-CSI-RS transmissions within a DRS window are shown according to various exemplary embodiments.

[0012] Figure 7 An example of collecting measurement data / results using NZP-CSI-RS from multiple DRS windows is shown according to various exemplary embodiments.

[0013] Figure 8 Examples of repeated NZP-CSI-RS sequences within a DRS window are shown according to various exemplary embodiments.

[0014] Figure 9a Methods for allocating dynamic Physical Random Access Channel (PRACH) resources from a UE's perspective are shown according to various exemplary embodiments.

[0015] Figure 9b Methods for allocating dynamic Physical Random Access Channel (PRACH) resources from a cell perspective are shown according to various exemplary embodiments.

[0016] Figure 10 An example of an allocation table is shown that may be provided to a UE to determine dynamic PRACH resources allocated to the UE, according to various exemplary embodiments.

[0017] Figure 11 An example of dynamic resource allocation in DCI format 2_0 according to various exemplary embodiments is shown. DETAILED DESCRIPTION

[0018] The exemplary embodiments may be further understood with reference to the following description and associated drawings, in which similar elements bear the same reference numerals. The exemplary embodiments relate to signaling between user equipment (UE) and a cell over unlicensed spectrum. As will be explained in greater detail below, in a first aspect, the exemplary embodiments relate to the transmission of reference signals over unlicensed spectrum. In a second aspect, the exemplary embodiments relate to a physical random access channel (PRACH) for unlicensed operation.

[0019] The exemplary embodiments are described with respect to a UE. However, the use of a UE is for illustrative purposes only. The exemplary embodiments can be utilized with any electronic component that can establish a connection to a network and is configured with hardware, software, and / or firmware for exchanging information and data with the network. Therefore, the term UE as used herein is intended to represent any electronic component.

[0020] Example embodiments are also described with reference to a UE communicating with a 5G New Radio (NR) network operating in an unlicensed spectrum (5G NR-U). However, reference to 5G NR-U is provided for illustrative purposes only. The example embodiments are applicable to any type of network operating in an unlicensed spectrum.

[0021] Unlicensed spectrum is a shared transmission medium that multiple different devices using multiple different communication protocols can utilize for communication. Therefore, access to unlicensed spectrum for NR-U purposes may involve various regulations and / or standards. For example, listen-before-talk (LBT) may be implemented in accordance with these regulations and / or standards to access unlicensed spectrum for communication. LBT may involve determining whether a channel in the unlicensed spectrum is occupied by other signals before performing a transmission over the unlicensed spectrum.

[0022] For example, a transmitting device (e.g., UE, cell, etc.) may perform a clear channel assessment (CCA) to sense whether a channel of an unlicensed spectrum that can be used for transmission is busy. If the channel is busy, the transmitting device may continue to perform CCA until it is determined that the channel is idle. Alternatively, if the channel is busy, the transmitting device may delay transmission by a fixed or dynamic duration until the channel of the unlicensed spectrum may be idle. Once it is determined that the channel is idle, the transmitting device may perform transmission through the unlicensed spectrum. However, reference to LBT is provided for illustrative purposes only, and different regulations or standards may refer to similar mechanisms or processes by different names.

[0023] Example embodiments are further described with reference to a discovery reference signal (DRS). Generally, DRS refers to a set of reference signals and / or synchronization signals transmitted by a cell. The UE may use the contents of the DRS for various operations, such as, but not limited to, cell detection, cell search procedures, channel state information (CSI) detection, CSI measurements, beam selection, beam management, and radio resource management (RRM). The DRS may be transmitted periodically in a time window referred to as a DRS window. Each DRS window is configured for a predetermined duration (e.g., 2 milliseconds (ms), 5 ms, 10 ms, etc.) and occurs at a predetermined periodicity (e.g., 20 ms, 40 ms, 80 ms, 140 ms, etc.). For example, a DRS window of (x) ms may be scheduled to occur every (y) ms. However, any reference to DRS and DRS windows is provided for illustrative purposes only, and different entities may refer to similar concepts by different names.

[0024] In a first aspect, exemplary embodiments relate to improving resource efficiency by implementing an exemplary CSI-RS configuration within a DRS. In conventional cases, due to the conventional configuration of CSI-RS within a DRS window, the UE must blindly search for various candidate CSI-RS positions within the DRS window for CSI measurement. This causes the UE to experience power consumption and increase signaling overhead. The exemplary embodiment uses a set of periodic non-zero power CSI-RS (NZP-CSI-RS) that is paired with a corresponding set of synchronization signal blocks (SSBs) within the DRS window. This exemplary configuration is a more efficient use of network resources and allows the UE to determine the position of the NZP-CSI-RS within the DRS window. Compared to the conventional configuration mentioned above, this exemplary configuration reduces the signaling overhead to transmit the configuration from the gNB to the UE and allows the UE to consume less power for CSI-RS detection / measurement. Various examples of exemplary CSI-RS configurations within DRS, CSI-RS detection techniques, CSI-RS transmissions, and CSI-RS sequence generation will be described in more detail below.

[0025] The exemplary embodiments are also described with reference to the Physical Random Access Channel (PRACH) procedure. Typically, the PRACH procedure can be used to achieve uplink synchronization between the UE and the cells of the network. Under normal circumstances, the network allocates the UE resources to be used during the PRACH procedure. If a LBT failure occurs during the PRACH procedure, the UE waits until the next scheduled resource to perform LBT again and attempt to perform PRACH signaling. However, this introduces unnecessary delays into the PRACH procedure.

[0026] In a second aspect, exemplary embodiments relate to implementing dynamic PRACH resource allocation. This exemplary approach is a more efficient use of network resources and minimizes channel access latency. Various examples of how a network can provide dynamic PRACH resources to a UE and how the UE can utilize the dynamic PRACH resources are described in more detail below.

[0027] Figure 1 A network arrangement 100 according to various exemplary embodiments is shown. The network arrangement 100 includes a UE 110. Those skilled in the art will appreciate that the UE 110 may be any type of electronic component configured to communicate via a network, such as a mobile phone, tablet, smartphone, phablet, embedded device, wearable device, Cat-M device, Cat-M1 device, MTC device, eMTC device, other types of Internet of Things (IoT) devices, etc. A practical network arrangement may include any number of UEs used by any number of users. Therefore, the example of a single UE 110 is provided for illustrative purposes only.

[0028] UE 110 can be configured to communicate directly with one or more networks. In the example of network arrangement 100, UE 110 can wirelessly communicate with a 5G New Radio (NR) radio access network (5G NR RAN) 120 and a wireless local access network (WLAN) 122. 5G NR RAN 120 can be configured to operate in an unlicensed spectrum (e.g., 5G NR-U). UE 110 can also communicate with other types of networks (e.g., LTE RAN, traditional RAN, etc.). UE 110 can also communicate with a network via a wired connection. Thus, UE 110 can include a 5G NR chipset for communicating with 5G NR RAN 120 and an ISM chipset for communicating with WLAN 122.

[0029] The 5G NR RAN 120 may be part of a cellular network that may be deployed by a network operator (e.g., Verizon, AT&T, Sprint, T-Mobile, etc.). The 5G NR RAN 120 may include, for example, a cell or base station (Node B, eNodeB, HeNB, eNBS, gNB, gNodeB, macrocell base station, microcell base station, small cell base station, femtocell base station, etc.) configured to send and receive communication traffic from a UE equipped with an appropriate cellular chipset. The WLAN 122 may include any type of wireless local area network (WiFi, hotspot, IEEE 802.11x network, etc.).

[0030] UE 110 may connect to 5G NR RAN 120 via cell 120A. Those skilled in the art will appreciate that any relevant procedures may be performed for UE 110 to connect to 5G NR RAN 120. For example, as described above, 5G NR RAN 120 may be associated with a specific network operator, with which UE 110 and / or its user has protocol and credential information (e.g., stored on a SIM card). Upon detecting the presence of 5G NR RAN 120, UE 110 may transmit corresponding credential information to associate with 5G NR RAN 120. More specifically, UE 110 may associate with a specific cell (e.g., cell 120A of 5G NR RAN 120). As described above, the use of 5G NR RAN 120 is for illustrative purposes, and any type of network may be used. For example, UE 110 may also connect to an LTE-RAN (not shown) or a legacy RAN (not shown).

[0031] Cell 120A may be equipped with one or more communication interfaces. For example, cell 120A may be equipped with a communication interface configured to communicate with a UE via unlicensed spectrum. In addition, cell 120A may be equipped with various processing components configured to perform various operations, such as, but not limited to, receiving signals from the UE and other network components, processing the received signals, and generating signals for transmission. For example, cell 120A may be equipped with one or more processors. The processors may include one or more baseband processors and / or one or more application processors. These processors may be configured to execute software and / or firmware. In another example, the cell may be equipped with an integrated circuit with or without firmware. For example, the integrated circuit may include input circuits for receiving signals, processing circuits for processing these signals, and output circuits for outputting the generated signals and information to other components (e.g., communication interfaces, transceivers, etc.). The functionality described herein for cell 120A may be implemented in any of these or other configurations of cells for a network known in the art.

[0032] In addition to networks 120 and 122, network arrangement 100 also includes a cellular core network 130. Cellular core network 130 can be considered an interconnected collection of components that manage the operation and traffic of a cellular network. Network arrangement 100 also includes the Internet 140, an IP Multimedia Subsystem (IMS) 150, and a network services backbone 160. Cellular core network 130 also manages traffic flowing between the cellular network and the Internet 140. IMS 150 can generally be described as an architecture for delivering multimedia services to UE 110 using IP protocols. IMS 150 can communicate with cellular core network 130 and the Internet 140 to provide multimedia services to UE 110. Network services backbone 160 communicates directly or indirectly with the Internet 140 and cellular core network 130. Network services backbone 160 can generally be described as a set of components (e.g., servers, network storage arrangements, etc.) that implement a suite of services that can be used to extend the functionality of UE 110 to communicate with various networks.

[0033] Figure 2 An exemplary UE 110 is shown according to various exemplary embodiments. Figure 1 10. The UE 110 may represent any electronic device and may include a processor 205, a memory arrangement 210, a display device 215, an input / output (I / O) device 220, a transceiver 225, and other components 230. The other components 230 may include, for example, an audio input device, an audio output device, a battery providing a limited power source, a data acquisition device, a port for electrically connecting the UE 110 to other electronic devices, sensors for detecting conditions of the UE 110, and the like.

[0034] The processor 205 may be configured to execute multiple engines of the UE 110. For example, the engines may include an NR-U CSI-RS engine 235. The NR-U CSI-RS engine 235 may perform various operations related to processing and utilizing CSI-RS received via unlicensed spectrum. For example, the NR-U CSI-RS engine 235 may be configured to determine the time and frequency location of the CSI-RS within a DRS window. The engines may also include an NR-U PRACH engine 240. The NR-U PRACH engine 240 may perform various operations related to PRACH procedures, such as determining when to perform a transmission using dynamic PRACH resources.

[0035] The above-described engines are each an application (e.g., a program) executed by the processor 205 for exemplary purposes only. The functionality associated with the engine may also be represented as a separate integrated component of the UE 110, or may be a modular component coupled to the UE 110, such as an integrated circuit with or without firmware. For example, an integrated circuit may include input circuitry for receiving signals and processing circuitry for processing signals and other information. The engine may also be embodied as one application or multiple independent applications. In addition, in some UEs, the functionality described for the processor 205 is shared between two or more processors, such as a baseband processor and an application processor. The exemplary embodiments may be implemented in any of these or other configurations of the UE.

[0036] The memory 210 may be a hardware component configured to store data related to operations performed by the UE 110. The display device 215 may be a hardware component configured to display data to a user, and the I / O device 220 may be a hardware component that enables user input. The display device 215 and the I / O device 220 may be separate components or may be integrated together (such as a touch screen). The transceiver 225 may be a hardware component configured to establish a connection with the 5G NR-RAN 120 and the WLAN 122. Thus, the transceiver 225 may operate on a variety of different frequencies or channels (e.g., a set of continuous frequencies).

[0037] Figure 3 A method 300 for channel state information reference signal (CSI-RS) reception according to various exemplary embodiments is shown. Method 300 provides a general overview of the context in which CSI-RS may be used by UE 110. Specific examples of exemplary CSI-RS configurations within a DRS window, CSI-RS detection techniques, CSI-RS transmissions, and CSI-RS sequence generation are described in greater detail below.

[0038] UE 110 enters the coverage area of a cell of the network at 305. For example, cell 120A may be deployed with a coverage area covering a particular geographic location.

[0039] At 310, UE 110 tunes transceiver 225 to a frequency associated with cell 120A. For example, UE 110 may be configured to search various frequencies for CSI-RS and / or SSB broadcast by the network according to any of a variety of different procedures. Procedure types include, but are not limited to, cell search, cell selection, cell reselection, synchronization, RRM, and the like.

[0040] At 315, UE 110 receives at least one DRS broadcast by cell 120A. For example, cell 120A may be configured to broadcast the DRS during a scheduled DRS window. UE 110 may receive the DRS when transceiver 225 of UE 110 is tuned to a frequency corresponding to cell 120A. As will be described in greater detail below, the DRS window may include multiple NZP-CSI-RS paired with corresponding SSBs. UE 110 may determine the time and frequency location of the NZP-CSI-RS using any of the detection techniques described below or any suitable detection technique.

[0041] In 320, UE 110 performs an operation based on one or more transmissions in the one or more DRS windows. For example, UE 110 may collect and / or average measurement data / results by measuring CSI-RS transmissions included in the one or more DRS windows. The measurement data may then trigger UE 110 to initiate an operation such as cell selection. In another example, UE 110 may perform operations related to beam selection and / or beam management. However, the exemplary embodiments are not limited to UE 110 utilizing measurement results in one or more DRS windows for any particular purpose. There are a variety of different operations performed by UE 110 that may be directly or indirectly affected by measurement results in one or more DRS windows, and the exemplary embodiments may be applied to any appropriate operation or process. Subsequently, method 300 ends.

[0042] Figure 4 An example of an exemplary channel state information reference signal (CSI-RS) arrangement within a discovery reference signal (DRS) window 400 according to various exemplary embodiments is shown. This example will be described with reference to a CSI-RS within the DRS window being an NZP-CSI-RS. However, the exemplary embodiments are not limited to NZP-CSI-RS and are applicable to any suitable type of reference signal or zero-power (ZP) CSI-RS or CSI interference measurement (CSI-IM).

[0043] The DRS window 400 represents a duration of 5ms. Within the DRS window 400, a 30 kilohertz (kHZ) subcarrier spacing and twenty synchronization signal blocks (SSBs) 410 to 429 are provided. Those skilled in the art will appreciate that each SSB may include at least one primary synchronization signal (PSS), at least one secondary synchronization signal (SSS), at least one physical broadcast channel (PBCH) demodulation reference signal (DMRS), and PBCH data. Each SSB 410 to 429 is paired with a corresponding NZP-CSI-RS, and therefore twenty NZP-CSI-RS 430 to 449 are included in the DRS window 400. Both the SSBs 410 to 429 and the NZP-CSI-RS 430 to 449 are indexed in ascending order from #0 to #19. The index # is shown below the SSBs 410 to 429. The above example describes the contents of the DRS window 400 using specific values. However, the above example is provided for illustrative purposes only. For example, the DRS window need not be configured for twenty NZP-CSI-RS instances. The DRS window can be configured for (M) NZP-CSI-RS and indexed from 0 to M-1. Those skilled in the art will appreciate that the exemplary configuration is applicable to any appropriate number of NZP-CSI-RS and SSBs.

[0044] As indicated above, each NZP-CSI-RS may be paired with an SSB. The network may configure the UE 110 to have the NZP-CSI-RS within an orthogonal frequency division multiplexing (OFDM) symbol of the corresponding SSB. The UE 110 may use the NZP-CSI-RS to generate CSI reports or RRM measurement data / results. From the perspective of the UE 110, the time and frequency position of the NZP-CSI-RS may be determined using any of a variety of different detection techniques. As will be described in more detail below, one exemplary detection technique may be based on a symbol offset and a resource block (RB) offset between the paired NZP-CSI-RS and the SSB. When the UE 110 is aware of the configured symbol offset and RB offset, the UE 110 may use the offset parameters to locate the NSZP-CSI-RS within the DRS window.

[0045] Each of the NZP-CSI-RSs 430 to 449 may be configured with a symbol offset parameter, which may be defined relative to the first symbol of its paired SSB 410 to 429. An example of a symbol offset is shown within the DRS window 400 as symbol offset 450, which is shown between the SSB 410 and the NZP-CSI-RS 430. While the symbol offset 450 is depicted for only a single pair of the NZP-CSI-RS 410 and the SSB 430, the symbol offset parameter may be implemented for each pair shown within the DRS window 400.

[0046] The DRS window 400 may also include a resource block (RB) offset 452. In some embodiments, the RB offset may be defined relative to the lowest RB of the corresponding SSB. In other embodiments, the RB offset may be defined relative to the highest RB of the corresponding SSB. In further embodiments, the starting RB for defining the RB offset may be explicitly configured by a system information block (SIB), such as SIB 1. Although the RB offset 452 is depicted only for a single pair of NSP-CSI-RS 430 and SSB 410, the RB offset may be implemented for each pair shown within the DRS window 400. Thus, the UE 110 may be preconfigured with values for a symbol offset parameter and an RB offset parameter, or may receive an indication of these offset parameters from the network. Thus, unlike conventional methods, the UE 110 does not need to blindly search each candidate position, as the UE 110 may use, at least in part, the offset parameters to determine the position of the NSP-CSI-RS.

[0047] In some exemplary embodiments, UE 110 may be provided with an indication of the frequency domain occupancy of the NZP-CSI-RS resources within DRS window 400. The frequency domain occupancy may be provided in RB units or any other suitable units. Thus, unlike conventional methods, UE 110 does not need to blindly search for each candidate position, as UE 110 may determine the position of the NZP-CSI-RS using, at least in part, the frequency domain occupancy information.

[0048] Figure 5 A table 500 illustrating a non-zero power channel state information reference signal (NZP-CSI-RS) configuration is shown. The information shown in table 500 may be used to encode and / or decode a DRS window.

[0049] Column 502 identifies the row index (0 to M) for each NZP-CSI-RS that may be included in the DRS window. For example, NZP-CSI-RS 430 to 449 depicted in DRS window 400 are indexed from 0 to 19. Thus, within the context of DRS window 400, M would be 20. Column 504 shows the symbol offset to be applied to the NZP-CSI-RS, identified by the index value in the corresponding row of table 500. In this example, the symbol offset is depicted in the table as Δ offset,tM Similarly, column 506 shows the RB offset to be applied to the NZP-CSI-RS, identified by the index value in the same row of table 500. In this example, the symbol offset is depicted in the table as Δ offset,fM .

[0050] Although not depicted in table 500, in some embodiments, an indication of frequency domain occupancy may also be included in this type of table. CSI-RS Available through B CSI-RS= B LBTsubband -B SSB is implicitly determined. Here, B LBTsubband represents the bandwidth of the listen - before - talk (LBT) operation and B SSB represents the bandwidth of the SSB. For NR - U, the bandwidth of the SSB can be twenty physical resource blocks (PRBs).

[0051] In some exemplary embodiments, the bitmap of the NZP - CSI - RS configuration can be provided by the network in the SIB. For example, cell 120A may broadcast the information in SIB1, which includes the bitmap of the NZP - CSI - RS configuration in the DRS window. In SIB1, if the most significant bit (MSB) k, k≥1 of the NZP - CSI - RS in the DRS is set to a first value (e.g., 1), then UE110 may assume that one or more NZP - CSI - RS candidates within the DRS paired with the SSBk - 1 with which it is quasi - co - located (QCL) are transmitted. If the MSBk, k≥1 is set to a second value (e.g., 0), then UE 110 may assume that the NZP - CSI - RS paired with the SSBk - 1 with which it is QCL is not transmitted.

[0052] According to another exemplary detection technique, if the CSI-RS mod value is the same among NZP - CSI - RS candidates, then UE 110 may assume that the NZP - CSI - RS broadcast by the serving cell (e.g., cell 120A) within or across the DRS window is QCL with respect to the average gain, QCL type A, and QCL type D attributes. N CSI-RS (0≤N CSI-RS <M) represents the NZP - CSI - RS index within the DRS window. In addition, may represent the number of non - QCL NZP - CSI - RS and can be provided by the network in SIB1 or PBCH. Alternatively, it can be determined based on the signaled for SSB transmission As will be explained below, the NZP - CSI - RS can be configured as a set, and the first NZP - CSI - RS included in the first set can be QCL with another NZP - CSI - RS in each of the other sets. This will be explained in more detail with reference to FIG. 6.

[0053] In some exemplary embodiments, if the corresponding paired SSB is not detected within the DRS window, then UE 110 may assume that the NZP - CSI - RS is not transmitted In other words, the presence of SSB is used as an indication of paired NZP-CSI-RS within the DRS window. , UE 110 may assume that no NZP-CSI-RS with index The NZP-CSI-RS of other QCLs of the UE 110 is detected and then CSI or RRM measurements are skipped based on the NZP-CSI-RS opportunity. This mechanism provides power saving benefits to the UE 110 because the UE 110 is not blindly searching for NZP-CSI-RS that has not been transmitted.

[0054] Figures 6a to 6b Examples of NZP-CSI-RS transmissions within a DRS window according to various exemplary embodiments are shown. Figure 4 The exemplary CSI-RS arrangement and DRS window 400 shown in FIG. Figures 6a to 6b Thus, in these examples, the DRS window 400 may include (M) NZP-CSI-RSs, where M=20. Figures 6a to 6b This relates to the transmission of a DRS by cell 120A. Although the DRS window 400 can accommodate up to twenty pairs of NZP-CSI-RS and SSB, fewer than twenty pairs may actually be transmitted.

[0055] In these examples, candidate NZP-CSI-RS 430 to 449 may be configured as sets, where each set includes four NZP-CSI-RSs. Each NZP-CSI-RS in one set is QCLed with the NZP-CSI-RSs in each of the other sets. During operation, UE 110 may assume that only one of the QCLed NZP-CSI-RSs is transmitted within the DRS window. Thus, in this example, There are four groups of QCL NZP-CSI-RSs. Group 1 includes NZP-CSI-RSs with indexes #: 0, 4, 8, 12, and 16. Group 2 includes NZP-CSI-RSs with indexes #: 1, 5, 9, 13, and 17. Group 3 includes NZP-CSI-RSs with indexes #: 2, 6, 10, 14, and 18. Group 4 includes NZP-CSI-RSs with indexes #: 3, 7, 11, 15, and 19.

[0056] The cell 120A may perform LBT before transmitting the NZP-CSI-RS and SSB pairs. As shown in examples 610 and 650, the cell 120A may be configured to transmit four pairs of NZP-CSI-RS and SSBs after LBT is successful.

[0057] Example 610 shows a case where LBT is successful before the first SSB (e.g., SSB index #0) is transmitted in the DRS window. Figure 6a 612 in the example. Therefore, the first pair of NZP-CSI-RS and SSB is transmitted. UE 110 may assume that if it receives NZP-CSI-RS, the NZP-CSI-RS of the other QCLs in the corresponding group are not transmitted. For example, in the context of example 610, NZP-CSI-RS 430 to 433 with indices #0 to #3 are transmitted. As shown above, NZP-CSI-RS index #0 is included in Group 1. Since NZP-CSI-RS index #0 is transmitted, UE 110 may assume that the other NZP-CSI-RS in Group 1 (e.g., #4, #8, #12, #16) are not transmitted. UE 110 may make similar assumptions for Groups 2 to 4. Therefore, UE 110 may assume that the remaining NZP-CSI-RS candidates (434 to 449) are not transmitted. This mechanism provides a power saving benefit to the UE 110 because the UE 110 is not blindly searching for a NAZP-CSI-RS that has not been transmitted.

[0058] Example 650 shows a case where LBT is successful before the fourth SSB (e.g., SSB index #3) is transmitted in the DRS window. Figure 6b 652 in the , and LBT failure is indicated by Figure 6b 654 in the example. Thus, in this example, the first three pairs of NZP-CSI-RS and SSB are not transmitted due to LBT failure. After LBT success 652, four consecutive NZP-CSI-RS pairs are transmitted. As mentioned above, UE 110 may assume that if it receives NZP-CSI-RS, the NZP-CSI-RS of other QCLs in the corresponding group are not transmitted. For example, in the context of example 650, NZP-CSI-RS 433 to 436 with indices #3 to #6 are transmitted. As shown above, NZP-CSI-RS index #3 is included in group 4. Since NZP-CSI-RS index #3 is transmitted, UE 110 may assume that the other NZP-CSI-RS in group 4 (e.g., #7, #11, #15, #19) are not transmitted. UE 110 may make similar assumptions for groups 1 to 3. Therefore, UE 110 may assume that the remaining NZP-CSI-RS candidates (437 to 449) are not transmitted.This mechanism provides a power saving benefit to UE 110 because UE 110 is not blindly searching for NAZP-CSI-RS that have not been transmitted.

[0059] In some embodiments, UE 110 may assume that certain NZP-CSIRS are not transmitted based on downlink control information (DCI). For example, UE 110 may be configured to monitor DCI format 2_0, which may include channel occupancy time (COT) duration information. If UE 110 does not detect a DCI format 2_0 indicating a configured NZP-CSI-RS within the COT duration, or detects a DCI format 2_0 indicating that any of the corresponding LBT bandwidths is unavailable for downlink reception, UE 110 may assume that cell 120A is not transmitting NZP-CSI-RS.

[0060] Figure 7 An example of collecting measurement data / results using NZP-CSI-RS from multiple DRS windows is shown according to various exemplary embodiments. Figure 7 Three DRS windows 705, 710, and 715 are shown. The dashed lines below each index #0 to #9 indicate a case where NZP-CSI-RS is not transmitted, for example, due to LBT failure on the gNB side. Alternatively, the solid lines below each index #0 to #9 indicate a case where NZP-CSI-RS is transmitted.

[0061] UE 110 may be configured to collect measurement data / results from multiple DRS windows and then average the measurement data / results over the NZP-CSI-RS time instances of the QCLs from different DRS windows. This technique may improve the accuracy of the CSI measurement data. In this example, RRM measurement data (e.g., Layer 1 (L1) Received Signal Strength Indicator (RSSI)) is collected from NZP-CSI-RS indices #2 to #5 in DRS window 705, NZP-CSI-RS indices #5 to #8 in DRS window 710, and NZP-CSI-RS indices #0 to #3 in DRS window 715. Figure 7 The arrows above the DRS windows 705 to 715 in show which NZP-CSI-RS are QCL in this example.The measurement data corresponding to the set of QCL NZP-CSI-RS can then be averaged together.

[0062] In some embodiments, UE 110 may be configured to utilize radio resource control (RRC) messages to perform the DRS window averaging described above. For example, during RRM measurement configuration, UE 110 may receive an RRC signal indicating whether UE 110 is to perform DRS window averaging.

[0063] In some embodiments, a threshold may be implemented to ensure that DRS window averaging is not affected by outliers. For example, if the L1 RSSI is not within a predetermined threshold, the L1 RSSI may be excluded from the averaging operation. This information may also be excluded from the corresponding L1 measurement report.

[0064] Figure 8 1 shows examples of repeated NZP-CSI-RS sequences within a DRS window according to various exemplary embodiments. Using repeated NZP-CSI-RS sequences can simplify CSI and RRM measurement calculations at UE 110. Figure 8 According to the equations shown in and provided below, each sequence is generated based on one NZP-CSI-RS transmission opportunity within a DRS window and then repeated in other transmission opportunities within the same DRS window.

[0065] Figure 8 A DRS window 400 and a set of (M) NZP-CSI-RSs are shown, where M=20. Therefore, the NZP-CSI-RSs are indexed from #0 to #19. In this example, four sequences are used. NZP-CSI-RS sequence 0 is generated based on the NZP-CSI-RS transmission opportunity identified by index #0, and then repeated for other transmission opportunities within the same DRS window (e.g., index #4, #8, #12 (not shown), #16). Similarly, NZP-CSI-RS sequence 1 is generated based on the NZP-CSI-RS transmission opportunity identified by index #1 and also including indexes #5, #9, #13 (not shown), and #17. NZP-CSI-RS sequence 2 is generated based on the NZP-CSI-RS transmission opportunity identified by index #2 and also including indexes #6, #10, #14 (not shown), and #19. The NZP-CSI-RS sequence 3 is generated based on the NZP-CSI-RS transmission opportunity identified by index #3 and including indexes #7, #11, #15 (not shown), and #19. The UE 110 may assume that the NZP-CSI-RS sequence r(m) for QCL is defined as:

[0066]

[0067] The pseudo-random sequence is initialized at the beginning of each OFDM symbol using the following equation:

[0068]

[0069] here, is the number of time slots in a radio frame, l is the first The number of OFDM symbols in the time slot of the transmission opportunity within the transmission opportunity, and n ID Configured by higher layers.

[0070] As mentioned above, in a second aspect, exemplary embodiments relate to implementing dynamic PRACH resource allocation. During a PRACH procedure, UE 110 is configured to send a message (e.g., msg1) to cell 120A. Those skilled in the art will appreciate that msg1 relates to a PRACH preamble. Conventionally, UE 110 is configured with a random access opportunity (RO) during which a PRACH transmission may occur. If LBT fails during the first RO, UE 110 may then attempt a PRACH transmission during the next scheduled RO. However, this causes the PRACH procedure to experience a delay. As will be explained in detail below, exemplary embodiments may include dynamically implementing a mapping between SSBs and available ROs based on a COT captured by cell 120A.

[0071] Figure 9a A method 900 for allocating dynamic physical random access channel (PRACH) resources from the perspective of a UE 110 is shown in accordance with various exemplary embodiments.

[0072] At 905, UE 110 receives a signal from cell 120A indicating a set of one or more PRACH resources allocated to UE 110. In some embodiments, the signal may be a DCI format 2_0 indicating a COT duration and a set of available RBs. In other embodiments, the signal may be a DCI format 1_0 for scheduling SIB1 transmissions. For example, DCI format 2_0, DCI format 1_0, or DCI format 1_1 may be configured to include an information element (IE) that provides an indication of a set of one or more PRACH resources.

[0073] In 910, UE 110 determines the dynamic PRACH resources allocated to UE 110. For example, the signal received in 905 may indicate a row index in an allocation table. The allocation table may be pre-configured at UE 110 or may be configured by SIB1. Figure 10 The allocation table is described in more detail.

[0074] Figure 10 An example of an allocation table 1000 is shown that may be provided to UE 110 to determine dynamic PRACH resources allocated to UE 110, according to various exemplary embodiments. Allocation table 1000 includes an index column 1002, a symbol offset (K3) column 1004, a frequency domain column (F) 1006 indicating the number of PRACH resources in the frequency domain, and a time domain column (T) 1008 indicating the number of PRACH resources in the time domain.

[0075] Figure 11An example of dynamic resource allocation in DCI format 2_0 according to various exemplary embodiments is shown. In this example, the symbol offset (K3) and index are defined relative to DCI format 2_0. The time domain and frequency domain are defined relative to the index.

[0076] Although not depicted in allocation table 1000, in some embodiments, LBT parameters may also be configured for each row of the allocation table. For example, to facilitate LBT operation, a gap (e.g., a number of symbols) may be maintained between each RO. The duration of the gap may be included in allocation table 1000 or may be preconfigured in any other suitable manner. Alternatively, a portion of the PRACH samples may be adjusted to create a gap between consecutive ROs. For example, the last sample of an earlier RO or the first sample of a subsequent PRACH format may be punctured.

[0077] Returning to method 900, at 915, UE 110 transmits a message to cell 120A using the dynamic PRACH resources assigned to UE 110. For example, UE 110 may transmit msg1 to cell 120A via the dynamic PRACH resources assigned to UE 110. The remainder of the PRACH procedure may then be performed.

[0078] In some embodiments, PRACH resources may be allocated based at least in part on the RRC state of the UE 110. Thus, a UE 110 in an RRC connected state may be allocated different PRACH resources than a UE 110 in an RRC idle state. For example, a UE 110 in an RRC idle state may be signaled in SIB1 whether an enhanced long sequence PRACH format is to be used for channel access. A UE 110 in an RRC connected state may be configured with separate PRACH resources having the same or different format than that configured for initial access (e.g., for contention-free random access (CFRA) or switching between different component carriers (CCs) in an unlicensed band).

[0079] In some embodiments, a long sequence may be configured by cell 120A for initial access, and a short sequence may be conditionally and dynamically transmitted within a COT initiated by cell 120A. The sequence length (e.g., long or short) may be configured by higher layers as part of an allocation table and then dynamically signaled in RRC signaling on a per-COT basis, e.g., via DCI format 2_0 after cell 120A acquires a COT.

[0080] Figure 9b A method 950 for allocating dynamic physical random access channel (PRACH) resources from the perspective of cell 120A is shown in accordance with various exemplary embodiments.

[0081] At 955, the network allocates dynamic PRACH resources to UE 110. In some embodiments, the dynamic PRACH resources may be allocated based at least in part on the RRC state of UE 110. For example, as indicated above, if UE 110 is in an RRC idle state, the network may configure a long sequence PRACH format to be used by UE 110 for channel access. If UE 110 is in an RRC connected state, the network may configure UE 110 with separate PRACH resources having the same or a different format than that configured for initial access (e.g., for contention-free random access (CFRA) or switching between different component carriers (CCs) on an unlicensed band).

[0082] In some embodiments, a long sequence may be configured by cell 120A for initial access by UE 110, and a short sequence may be conditionally and dynamically transmitted within the COT initiated by cell 120A. The sequence length (e.g., long or short) may be included by higher layers as part of an allocation table and then dynamically signaled in RRC signaling on a per-COT basis, for example, via DCI format 2_0 after cell 120A captures the corresponding COT. However, the exemplary embodiments are not limited to allocating resources to UE 110 on any particular basis. The exemplary embodiments may be applicable to networks that allocate PRACH resources based on any appropriate basis (e.g., RRC state of UE 110, network load, congestion, measurement data, etc.).

[0083] In 960, cell 120A transmits a signal to UE 110 indicating one or more sets of PRACH resources allocated to UE 110. In some embodiments, the signal may be a DCI format 2_0 for indicating the COT duration and the set of available RBs. In other embodiments, the signal may be a DCI format 1_0 for scheduling SIB1 transmissions. For example, DCI format 2_0, DCI format 1_0, or DCI format 1_1 may be configured to include an information element (IE) that provides an indication of a set of one or more PRACH resources. The signal transmitted in 960 may indicate a row index in an allocation table. The allocation table may be preconfigured at UE 110 or may be configured by a previously transmitted SIB1. See above for Figure 10 Describes the allocation table.

[0084] In 965, cell 120A receives a message from UE 110 transmitted using the dynamic PRACH resources assigned to UE 110. For example, as indicated above, UE 110 may transmit msg1 to cell 120A over the dynamic PRACH resources assigned to UE 110. The remainder of the PRACH procedure may then be performed.

[0085] Some examples of the second aspect of the exemplary embodiment are provided below.

[0086] A first example relates to a method performed by a user equipment (UE). The method includes: receiving a signal broadcast by a cell of a network over a channel in an unlicensed spectrum, wherein the signal includes an indication that one or more physical random access channel (PRACH) resources have been allocated to the UE; determining a time and frequency location of the one or more PRACH resources based on the indication and an allocation information set; and transmitting an uplink signal to the cell using the one or more PRACH resources.

[0087] The method as described above, wherein the signal is one of downlink control information (DCI) format 1_0 or DCI format 2_0. The method as described above, wherein the uplink signal is message 1 (msg1).

[0088] The method as described above, wherein the UE is pre-configured with allocation information or receives allocation information in a system information block (SIB).

[0089] A method as described above, wherein the indication includes an index and the allocation information includes: i) a symbol offset, ii) time domain information, iii) frequency domain information, and wherein the symbol offset is defined relative to the position of a signal broadcast by a cell, the time domain information is defined relative to the index, and the frequency domain information is defined relative to the index.

[0090] Those skilled in the art will appreciate that the exemplary embodiments described above can be implemented with any suitable software configuration or hardware configuration or combination thereof. Exemplary hardware platforms for implementing the exemplary embodiments may include, for example, Intel x86-based platforms with compatible operating systems, Windows OS, Mac platforms and MAC OS, mobile devices with operating systems such as iOS, Android, etc. In other examples, the exemplary embodiments of the above methods may be embodied as a program comprising lines of code stored on a non-transitory computer-readable storage medium, which, when compiled, can be executed on a processor or microprocessor.

[0091] Although this patent application describes various combinations of various embodiments, each with different features, those skilled in the art will understand that any feature of one embodiment may be combined with features of other embodiments in any manner not publicly denied, or with features that are not functionally or logically inconsistent with the operation or described function of the device of the embodiments disclosed herein.

[0092] 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.

[0093] It will be apparent to those skilled in the art that various modifications may be made to the present disclosure without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is intended to cover modifications and variations of the present disclosure provided that these modifications and variations are within the scope of the appended claims and their equivalents.

Claims

1. A computer-readable storage medium comprising a set of instructions, wherein the set of instructions, when executed by a processor of a user equipment (UE), causes the processor to perform operations comprising: receiving a signal broadcast by a cell of a network over a channel in an unlicensed spectrum, wherein the signal comprises a set of channel state information reference signals (CSI-RSs), each CSI-RS set corresponding to a synchronization signal block (SSB) set and transmitted during a discovery reference signal (DRS) window; determining a position of the CSI-RS set within the DRS window; performing an operation based on the CSI-RS set; Determining quasi co-location (QCL) of the first CSI-RS and one or more other CSI-RSs; as well as Based on determining that the first CSI-RS and the one or more other CSI-RS QCLs in the DRS window exist, determining that the cell does not transmit the one or more CSI-RSs, wherein based on The first CSI-RS transmission is assumed to be QCL, where N CSI-RS represents the CSI-RS index within the DRS window, and It represents the number of non-zero power CSI-RS for non-QCL and is provided by the network in the System Information Block 1 (SIB1) or the Physical Broadcast Channel (PBCH). 2 . The computer-readable storage medium of claim 1 , wherein determining the position of the CSI-RS set is based on a first offset parameter and a second offset parameter.

3. The computer-readable storage medium of claim 2, wherein the first offset parameter is a symbol offset associated with a first CSI-RS and a first SSB positioned within the same orthogonal frequency division multiplexing (OFDM) symbol.

4. The computer-readable storage medium of claim 2, wherein the second offset parameter is a resource block (RB) offset associated with a first CSI-RS and a first SSB.

5. The computer-readable storage medium of claim 4, wherein the RB offset is defined relative to a lowest RB of the first SSB or a highest RB of the first SSB. 6 . The computer-readable storage medium of claim 1 , wherein determining the position of the CSI-RS set is based on determining frequency domain occupancy of CSI-RS resources within the DRS window.

7. The computer-readable storage medium of claim 6, wherein the frequency domain occupancy of the CSI-RS resources within the DRS window is determined based on a bandwidth associated with a listen-before-talk (LBT) operation and a bandwidth associated with the SSB set.

8. The computer-readable storage medium of claim 1, wherein determining the position of the CSI-RS set is based on a bitmap included in a system information block (SIB).

9. The computer-readable storage medium of claim 1 , the operations further comprising: Initialize the pseudo-random sequence r(m) at the beginning of each OFDM symbol and apply it to the CSI-RS of all QCLs within the DRS window, where the initialization is based on where c() represents a pseudo-random sequence initialized with the following equation: in Indicates the number of symbols in a time slot, is the number of time slots in a radio frame, l is the first The number of OFDM symbols in the time slot of the transmission opportunity within the transmission opportunity, and n ID Configured by higher layers.

10. The computer-readable storage medium of claim 1, the operations further comprising: A first DCI format is received to determine a physical random access channel (PRACH) resource allocation within a channel occupancy time (COT) indicated by a second DCI format.

11. The computer-readable storage medium of claim 10, wherein the first DCI and the second DCI are DCI format 2_0.

12. The computer-readable storage medium of claim 10, wherein the first DCI is DCI format 1_1 and the second DCI is DCI format 2_0.

13. The computer-readable storage medium of claim 10, wherein a physical random access channel (PRACH) resource is allocated based on a row index of an allocation table configured or preconfigured by SIB1.

14. A user equipment (UE), comprising: a transceiver configured to communicate with a network; and A processor configured to perform operations comprising: receiving a signal broadcast by a cell of the network over a channel in an unlicensed spectrum, wherein the signal comprises a set of channel state information reference signals (CSI-RSs), each CSI-RS set corresponding to a synchronization signal block (SSB) set and transmitted during a discovery reference signal (DRS) window; determining a position of the CSI-RS set within the DRS window; performing an operation based on the CSI-RS set; determining quasi co-location (QCL) of the first CSI-RS and one or more other CSI-RSs; and Based on determining that the first CSI-RS and the one or more other CSI-RS QCLs in the DRS window exist, determining that the cell does not transmit the one or more CSI-RSs, wherein based on The first CSI-RS transmission is assumed to be QCL, where N CSI-RS represents the CSI-RS index within the DRS window, and It represents the number of non-zero power CSI-RS for non-QCL and is provided by the network in the System Information Block 1 (SIB1) or the Physical Broadcast Channel (PBCH). 15 . The UE of claim 14 , wherein determining the position of the CSI-RS set is based on a first offset parameter and a second offset parameter.

16. The UE of claim 15, wherein the first offset parameter is a symbol offset associated with a first CSI-RS and a first SSB positioned within the same Orthogonal Frequency Division Multiplexing (OFDM) symbol.

17. The UE of claim 15, wherein the second offset parameter is a resource block (RB) offset associated with a first CSI-RS and a first SSB, and wherein the RB offset is defined relative to a lowest RB of the first SSB or a highest RB of the first SSB.

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