Downlink Synchronization for Non-Terrestrial Wireless Communication

Abstract

Methods, systems, and devices for wireless communication are described. A narrowband Internet of Things (NB-IoT) user equipment (UE) associated with a non-terrestrial wireless network may identify a first synchronization procedure that is specific to the non-terrestrial network and different from a synchronization procedure specific to a terrestrial network. In some cases, the UE may identify different channel raster, or may receive an indication of the true operating frequency of a narrowband cell in the non-terrestrial network. The UE may identify a narrowband cell associated with the non-terrestrial network and may synchronize with the network using the identified synchronization procedure.

Description

[0001] Cross-reference

[0002] This patent application claims priority to U.S. Patent Application No. 17 / 348,491, entitled "DOWNLINK SYNCHRONIZATION FOR NON-TERRESTRIAL WIRELESS COMMUNICATIONS," filed on June 15, 2021, by SENGUPTA et al., and U.S. Patent Application No. 63 / 047,247, entitled "DOWNLINK SYNCHRONIZATION FOR NON-TERRESTRIAL WIRELESS COMMUNICATIONS," filed on July 1, 2020, by SENGUPTA et al., each of which is assigned to the assignee of this application and is hereby incorporated by reference in its entirety. Field of the Disclosure

[0003] The following generally relates to wireless communications and, more particularly, to downlink synchronization for non-terrestrial wireless communications.

[0004] Background

[0005] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcasting, and the like. These systems may be capable of supporting communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multi-access systems include fourth-generation (4G) systems (such as Long-Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems) and fifth-generation (5G) systems, which may be referred to as New Radio (NR) systems. These systems may employ various techniques such as code-division multiple access (CDMA), time-division multiple access (TDMA), frequency-division multiple access (FDMA), orthogonal frequency-division multiple access (OFDMA), or discrete Fourier transform spread orthogonal frequency-division multiplexing (DFT-S-OFDM). A wireless multi-access communication system may include one or more base stations or one or more network access nodes, each of which simultaneously supports communication for multiple communication devices, which may also be referred to as user equipment (UE).

[0006] Some wireless communication networks may be narrowband (NB) Internet of Things (IoT) networks that support non-terrestrial communication. NB-IoT non-terrestrial networks may have characteristics different from those of terrestrial networks. As such, conventional signaling techniques for terrestrial networks may not be suitable or efficient when implemented in non-terrestrial networks.

[0007] Summary

[0008] The described technology relates to improved methods, systems, devices, and apparatuses for supporting downlink synchronization for wireless communication, such as non-terrestrial narrowband (NB) Internet of Things (IoT) communication. Generally, the described technology provides an increased likelihood of a user equipment (UE) establishing communication with an NB cell within a non-terrestrial radio network. Some NB-IoT networks may support various synchronization techniques to facilitate communication between devices in the network. Such synchronization techniques can also increase communication reliability in a non-terrestrial NB-IoT network, which may be associated with higher errors due to characteristics of the non-terrestrial network that are different from those of a terrestrial network (e.g., higher operating frequencies, Doppler effects, increased distances between devices). A non-terrestrial UE can identify a first synchronization protocol that is specific to the non-terrestrial network and different from a synchronization procedure specific to a terrestrial network. For example, the UE can identify a different channel raster, or the UE can receive an indication of the true operating frequency of the NB cell. The UE can identify an NB cell associated with the non-terrestrial network and can synchronize with the NB cell using the identified synchronization protocol.

[0009] A method for wireless communication at a UE is described. The method can include: identifying a first synchronization protocol that is specific to the non-terrestrial network and different from a second synchronization protocol specific to the terrestrial network; identifying a cell associated with the non-terrestrial network for synchronization with the UE; and synchronizing with the identified cell by performing the identified synchronization protocol.

[0010] An apparatus for wireless communication at a UE is described. The apparatus can include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions can be executed by the processor to cause the apparatus to: identify a first synchronization protocol that is specific to the non-terrestrial network and different from a second synchronization protocol specific to the terrestrial network; identify a cell associated with the non-terrestrial network for synchronization with the UE; and synchronize with the identified cell by performing the identified synchronization protocol.

[0011] Another device for wireless communication at a UE is described. The device can include: means for identifying a first synchronization protocol that is specific to the non-terrestrial network and different from a second synchronization protocol specific to the terrestrial network; means for identifying a cell associated with the non-terrestrial network for synchronization with the UE; and means for synchronizing with the identified cell by performing the identified synchronization protocol.

[0012] Describes a non-transitory computer-readable medium storing code for wireless communication at a UE. The code may include instructions executable by a processor to perform the following operations: identify a first synchronization procedure specific to a non-terrestrial network and different from a second synchronization procedure specific to a terrestrial network; identify a cell associated with the non-terrestrial network for synchronization with the UE; and synchronize with the identified cell by executing the identified synchronization procedure.

[0013] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, identifying the first synchronization procedure may include operations, features, apparatuses, or instructions for the following actions: identifying a first channel raster at a frequency specific to the non-terrestrial network and different from a second channel raster at a frequency specific to the terrestrial network; identifying a set of one or more frequency positions of at least one anchor carrier according to the first channel raster; and monitoring the at least one anchor carrier for one or more downlink synchronization signals, wherein synchronization with the cell may be based on the one or more downlink synchronization signals.

[0014] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the first channel raster includes a cell carrier spacing that increases in frequency relative to the second channel raster.

[0015] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may further include operations, features, apparatuses, or instructions for the following actions: receiving an information block specific to the non-terrestrial network, the information block including an indication of a true value of a carrier frequency associated with the cell.

[0016] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may further include operations, features, apparatuses, or instructions for the following actions: comparing a first carrier frequency with the true value of the carrier frequency of the cell; and selectively maintaining or discarding a connection with the cell based on the comparison.

[0017] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, selectively maintaining or discarding a connection with the cell may include operations, features, apparatuses, or instructions for the following actions: determining that the first carrier frequency matches the true value of the carrier frequency of the cell; and maintaining a connection with the cell based on the first carrier frequency matching the true value of the carrier frequency.

[0018] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, determining whether to maintain a connection to a cell may include operations, features, apparatuses, or instructions for the following actions: determining that a first carrier frequency may be different from the true value of the carrier frequency of the cell; and discarding the connection to the cell based on the first carrier frequency being different from the true value of the carrier frequency.

[0019] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, an information block including an indication of the true value of the carrier frequency further includes at least a portion of an absolute radio frequency channel number (ARFCN) for the cell.

[0020] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the information block may be a system information block (SIB) including the at least a portion of the ARFCN.

[0021] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the information block includes a master information block (MIB).

[0022] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the MIB includes a set of the least significant bits of the ARFCN.

[0023] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may further include operations, features, apparatuses, or instructions for the following actions: identifying a valid mapping between the ARFCN and a cell identifier (ID) associated with the cell, wherein synchronization with the identified cell is based on the valid mapping.

[0024] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may further include operations, features, apparatuses, or instructions for the following actions: determining that the valid mapping includes a first association between odd-numbered ARFCNs and odd-numbered cell IDs or a second association between even-numbered ARFCNs and even-numbered cell IDs.

[0025] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may further include operations, features, apparatuses, or instructions for the following actions: receiving one or more synchronization signals associated with a first synchronization procedure, wherein the one or more synchronization signals include narrowband synchronization signals.

[0026] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, a cell may be a narrowband cell serving one or more NB-IoT-specific UEs.

[0027] A method for wireless communication at a base station is described. The method may include: identifying a first synchronization procedure specific to a non-terrestrial network and different from a second synchronization procedure specific to a terrestrial network; identifying a UE associated with the non-terrestrial network for synchronization with a cell associated with the base station; and synchronizing with the identified UE by performing the identified synchronization procedure.

[0028] An apparatus for wireless communication at a base station is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to: identify a first synchronization procedure specific to a non-terrestrial network and different from a second synchronization procedure specific to a terrestrial network; identify a UE associated with the non-terrestrial network for synchronization with a cell associated with the base station; and synchronize with the identified UE by performing the identified synchronization procedure.

[0029] Another device for wireless communication at a base station is described. The device may include: means for identifying a first synchronization procedure specific to a non-terrestrial network and different from a second synchronization procedure specific to a terrestrial network; means for identifying a UE associated with the non-terrestrial network for synchronization with a cell associated with the base station; and means for synchronizing with the identified UE by performing the identified synchronization procedure.

[0030] A non-transitory computer-readable medium storing code for wireless communication at a base station is described. The code may include instructions executable by a processor to: identify a first synchronization procedure specific to a non-terrestrial network and different from a second synchronization procedure specific to a terrestrial network; identify a UE associated with the non-terrestrial network for synchronization with a cell associated with the base station; and synchronize with the identified UE by performing the identified synchronization procedure.

[0031] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, identifying the first synchronization procedure may include operations, features, means, or instructions for the following actions: identifying a first channel raster at a frequency specific to the non-terrestrial network and different from a second channel raster at a frequency specific to the terrestrial network; identifying, based on the first channel raster, a set of one or more frequency positions of at least one anchor carrier; and transmitting the at least one anchor carrier including one or more downlink synchronization signals, wherein synchronization with the UE may be based on the one or more downlink synchronization signals.

[0032] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, a first channel raster includes a cell carrier spacing that increases in frequency relative to a second channel raster.

[0033] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may further include operations, features, apparatuses, or instructions for the following actions: transmitting an information block specific to a non-terrestrial network, the information block including an indication of a true value of a first carrier frequency associated with a cell.

[0034] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may further include operations, features, apparatuses, or instructions for the following actions: comparing a first carrier frequency with a true value of a carrier frequency of a cell; and selectively maintaining or discarding a connection with a UE based on a comparison of the first carrier frequency with the true value of the carrier frequency of the cell.

[0035] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, selectively maintaining or discarding a connection with a cell may include operations, features, apparatuses, or instructions for the following actions: maintaining a connection with a UE based on a match between a first carrier frequency and a true value of a carrier frequency.

[0036] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, determining whether to maintain a connection with a cell may include operations, features, apparatuses, or instructions for the following actions: discarding a connection with a UE based on a first carrier frequency being different from a true value of a carrier frequency.

[0037] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may further include operations, features, apparatuses, or instructions for the following actions: transmitting an information block that further includes at least a portion of an ARFCN for a cell to indicate a true value of a carrier frequency.

[0038] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the information block includes an MIB, the MIB including a set of the plurality of least significant bits of an ARFCN.

[0039] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the information block may be an SIB including an ARFCN.

[0040] Some examples of the methods, apparatuses (devices), and non-transitory computer-readable media described herein may further include operations, features, apparatuses, or instructions for the following actions: identifying a valid mapping between an ARFCN and a cell ID associated with a cell, wherein synchronization with a UE may be based on the valid mapping; and determining that the valid mapping includes a first association between odd-numbered ARFCNs and odd-numbered cell IDs or a second association between even-numbered ARFCNs and even-numbered cell IDs.

[0041] Some examples of the methods, apparatuses (devices), and non-transitory computer-readable media described herein may further include operations, features, apparatuses, or instructions for the following actions: transmitting one or more synchronization signals associated with a first synchronization procedure, wherein the one or more synchronization signals include narrowband synchronization signals.

[0042] In some examples of the methods, apparatuses (devices), and non-transitory computer-readable media described herein, a base station serves one or more NB-IoT-specific UEs. Brief Description of the Drawings

[0044] Figure 1 An example of a wireless communication system supporting downlink synchronization for non-terrestrial wireless communication in accordance with aspects of the present disclosure is illustrated.

[0045] Figure 2 An example of a wireless communication system supporting downlink synchronization for non-terrestrial wireless communication in accordance with aspects of the present disclosure is illustrated.

[0046] Figure 3 An example of a process flow supporting downlink synchronization for non-terrestrial wireless communication in accordance with aspects of the present disclosure is illustrated.

[0047] Figure 4 and 5 A block diagram of an apparatus supporting downlink synchronization for non-terrestrial wireless communication in accordance with aspects of the present disclosure is shown.

[0048] Figure 6 A block diagram of a communication manager supporting downlink synchronization for non-terrestrial wireless communication in accordance with aspects of the present disclosure is shown.

[0049] Figure 7 A diagram of a system including an apparatus supporting downlink synchronization for non-terrestrial wireless communication in accordance with aspects of the present disclosure is shown.

[0050] Figure 8 and 9 A block diagram of an apparatus supporting downlink synchronization for non-terrestrial wireless communication in accordance with aspects of the present disclosure is shown.

[0051] Figure 10 A block diagram of a communication manager supporting downlink synchronization for non-terrestrial wireless communication in accordance with aspects of the present disclosure is shown.

[0052] Figure 11 A diagram of a system including a device supporting downlink synchronization for non-terrestrial wireless communication in accordance with aspects of the present disclosure is shown.

[0053] Figures 12 to 16 A flowchart depicting a method supporting downlink synchronization for non-terrestrial wireless communication in accordance with aspects of the present disclosure is shown.

[0054] Detailed Description

[0055] Some wireless communication networks, such as narrowband (NB) Internet of Things (IoT) networks, may support various synchronization techniques to facilitate communication between devices in the network. One such technique employs the use of a channel raster, which may indicate an index of frequency positions of anchor carriers or NB-IoT resource blocks that a user equipment (UE) can use to search for during cell capture for initial synchronization. The anchor carriers may include various downlink synchronization signals that are positioned at intervals given by the frequency positions of the channel raster that the UE can use for synchronization.

[0056] In a terrestrial NB-IoT deployment, the UE may estimate the frequency of a carrier during an initial synchronization process along with an initial frequency estimation error associated with the initial frequency estimate. In some examples, the initial frequency estimation error is small enough (e.g., relative to the total frequency estimate) such that the UE can accurately estimate the frequency of the carrier and, in some cases, establish communication with a terrestrial NB-IoT cell. That is, the channel raster for a terrestrial system can be large enough (e.g., relative to the frequency estimation error) such that the UE can accurately estimate the actual carrier frequency and establish communication with a terrestrial NB cell.

[0057] However, in non-terrestrial deployments, due to the higher operating frequencies, Doppler shift effects, and other factors (such as the movement of the UE in the non-terrestrial network), the initial frequency estimation error for the UE can be much larger compared to the error measured in terrestrial systems. Based on the characteristics of non-terrestrial communication (e.g., the long distance between the UE and the satellite, the satellite orbital motion, interference, and Doppler effects), the UE in the non-terrestrial network may misestimate the frequency of the NB IoT carrier and may attempt to establish a connection with the NB cell using the misestimated frequency. Subsequently, the UE may expect to receive communication from the cell at the misestimated frequency that is different from the frequency on which the NB cell is operating. Such a mismatch between the frequency the UE expects to receive and the actual transmitted frequency when operating a non-terrestrial network can introduce communication challenges (e.g., lost or dropped transmissions).

[0058] To improve communication efficiency and effectively reduce the impact of the large errors and large initial channel frequency offsets in non-terrestrial networks, the network can implement several different techniques to increase the likelihood that the UE can effectively connect to the correct NB cell and that the UE can estimate the correct frequency associated with the NB cell. In one example, the frequency spacing associated with the channel raster for a non-terrestrial NB-IoT network can be increased such that the spacing between the effective NB-IoT anchor carrier positions is increased relative to those in terrestrial networks, and the UE can search for the NB-IoT anchor carrier at the frequency positions specified by the channel raster.

[0059] In another example, the UE can establish communication with the NB cell and can receive a master information block (MIB) or a system information block (SIB) that is specific to non-terrestrial network communication and includes information such as an indication of the true value of the NB-IoT anchor carrier frequency associated with the NB cell. For example, the MIB or SIB can include at least a portion of the absolute radio frequency channel number (ARFCN) that indicates the frequency of the cell. The UE can use the ARFCN to determine that the operating frequency of the NB cell is different from the frequency the UE expects to transmit on, and the UE can disconnect from the cell and attempt to synchronize with a different NB cell.

[0060] In another example, the non-terrestrial network can limit the numbering of the NB cell IDs available for each ARFCN based on an effective mapping between the NB cell ID and the ARFCN. In some examples, even-numbered ARFCNs can be associated with even-numbered NB cell IDs, while odd-numbered ARFCNs can be associated with odd-numbered cell IDs, although other effective mappings are possible.

[0061] Aspects of the present disclosure are initially described in the context of a wireless communication system, including a non-terrestrial wireless communication system. Aspects of the present disclosure are further illustrated and described by and with reference to apparatus diagrams, system diagrams, process flow diagrams, and flowcharts related to downlink synchronization for non-terrestrial wireless communication.

[0062] Figure 1 An example of a wireless communication system 100 that supports downlink synchronization for non-terrestrial wireless communication in accordance with aspects of the present disclosure is illustrated. The wireless communication system 100 may include one or more base stations 105, one or more UEs 115, and a core network 130. In some examples, the wireless communication system 100 may be a Long-Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some examples, the wireless communication system 100 may support enhanced broadband communication, ultra-reliable (e.g., mission-critical) communication, low-latency communication, communication with low-cost and low-complexity devices, or any combination thereof.

[0063] The base stations 105 may be dispersed throughout a geographic area to form the wireless communication system 100, and may be different forms of devices or devices with different capabilities. The base stations 105 and the UEs 115 may communicate wirelessly via one or more communication links 125. Each base station 105 may provide a coverage area 110, and the UEs 115 and the base stations 105 may establish one or more communication links 125 over the coverage area 110. The coverage area 110 may be an example of a geographic area over which the base stations 105 and the UEs 115 may support signal communication in accordance with one or more radio access technologies.

[0064] The UEs 115 may be dispersed throughout the coverage area 110 of the wireless communication system 100, and each UE 115 may be stationary or mobile, or stationary and mobile at different times. The UEs 115 may be different forms of devices or devices with different capabilities. Some example UEs 115 are illustrated in Figure 1 . The UEs 115 described herein may be capable of communicating with various types of devices, such as other UEs 115, base stations 105, or network equipment (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network equipment), as shown in Figure 1 .

[0065] Each base station 105 can communicate with the core network 130, communicate with each other, or do both. For example, the base station 105 can interface with the core network 130 via one or more backhaul links 122 (e.g., via S1, N2, N3, or other interfaces). The base stations 105 can communicate with each other directly (e.g., directly between each base station 105), or indirectly (e.g., via the core network 130), or directly and indirectly over the backhaul links 122 (e.g., via X2, Xn, or other interfaces). In some examples, the backhaul link 122 can be or include one or more wireless links.

[0066] One or more of the base stations 105 described herein can include or can be referred to by those of ordinary skill in the art as a base transceiver station, radio base station, access point, radio transceiver, Node B, evolved Node B (eNB), next-generation Node B, or giga Node B (any of which can be referred to as a gNB), home Node B, home evolved Node B, or other suitable terms.

[0067] The UE 115 can include or can be referred to as a mobile device, wireless device, remote device, handheld device, or subscriber device, or some other suitable term, where "device" can also be referred to as a unit, station, terminal, or client, etc. The UE 115 can also include or can be referred to as a personal electronic device, such as a cellular phone, personal digital assistant (PDA), tablet computer, laptop computer, or personal computer. In some examples, the UE 115 can include or be referred to as a wireless local loop (WLL) station, Internet of Things (IoT) device, Internet of Everything (IoE) device, or machine type communication (MTC) device, etc., which can be implemented in various objects such as appliances, vehicles, meters, etc.

[0068] The UE 115 described herein can be capable of communicating with various types of devices (such as other UEs 115 that can sometimes act as relays, as well as base stations 105 and network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, relay base stations, etc.), as Figure 1 shown.

[0069] UE 115 and base station 105 may wirelessly communicate with each other via one or more communication links 125 over one or more carriers. The term "carrier" may refer to a collection of one or more radio frequency spectrum resources having a defined physical layer structure for supporting communication link 125. For example, a carrier for communication link 125 may include a portion of a radio frequency spectrum band (e.g., bandwidth part (BWP)) operating according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information), control signaling for coordinating carrier operation, user data, or other signaling. Wireless communication system 100 may support communicating with UE 115 using carrier aggregation or multi-carrier operation. UE 115 may be configured to have multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may be used in conjunction with both frequency division duplex (FDD) and time division duplex (TDD) component carriers.

[0070] In some examples (e.g., in a carrier aggregation configuration), a carrier may also have acquisition signaling or control signaling for coordinating the operation of other carriers. A carrier may be associated with a frequency channel (e.g., evolved universal mobile telecommunications system terrestrial radio access (E-UTRA) absolute radio frequency channel number (EARFCN)) and may be positioned according to a channel raster for discovery by UE 115. A carrier may operate in a stand-alone mode in which initial acquisition and connection may be performed by UE 115 via the carrier, or a carrier may operate in a non-stand-alone mode in which the connection is anchored using a different carrier (e.g., different carriers of the same or different radio access technologies).

[0071] The communication link 125 shown in wireless communication system 100 may include an uplink transmission from UE 115 to base station 105, or a downlink transmission from base station 105 to UE 115. A carrier may carry downlink or uplink communication (e.g., in FDD mode), or may be configured to carry both downlink communication and uplink communication (e.g., in TDD mode).

[0072] A carrier can be associated with a specific bandwidth of the radio frequency spectrum, and in some examples, the carrier bandwidth can be referred to as the "system bandwidth" of the carrier or the wireless communication system 100. For example, the carrier bandwidth can be one of several determined bandwidths of a carrier of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 megahertz (MHz)). Devices of the wireless communication system 100 (e.g., the base station 105, the UE 115, or both) can have a hardware configuration that supports communication on a specific carrier bandwidth, or can be configurable to support communication on a carrier bandwidth within a set including one or more carrier bandwidths. In some examples, the wireless communication system 100 can include a base station 105 or a UE 115 that supports simultaneous communication via carriers associated with multiple carrier bandwidths. In some examples, each served UE 115 can be configured to operate on a portion (e.g., a subband, a BWP) or all of the carrier bandwidth.

[0073] The signal waveform transmitted on a carrier can include multiple subcarriers (e.g., using a multi-carrier modulation (MCM) technique, such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In a system employing an MCM technique, a resource element can contain one symbol period (e.g., the duration of one modulated symbol) and one subcarrier, where the symbol period and the subcarrier spacing are inversely related. The number of bits carried by each resource element can depend on the modulation scheme (e.g., the order of the modulation scheme, the code rate of the modulation scheme, or both). Thus, the more resource elements the UE 115 receives and the higher the order of the modulation scheme, the higher the data rate of the UE 115 can be. Wireless communication resources can refer to a combination of radio frequency spectrum resources, time resources, and spatial resources (e.g., spatial layers or beams), and using multiple spatial layers can further increase the data rate or data integrity of communication with the UE 115.

[0074] One or more parameter sets can be supported for a carrier, where a parameter set can include a subcarrier spacing (Δf) and a cyclic prefix. A carrier can be divided into one or more BWPs with the same or different parameter sets. In some examples, the UE 115 can be configured with multiple BWPs. In some examples, a single BWP for a carrier can be active at a given time, and communication for the UE 115 can be limited to one or more active BWPs.

[0075] The time intervals of the base station 105 or the UE 115 can be expressed as multiples of a basic time unit, which can refer to, for example, the sampling period T s = 1 / (Δf max ·N f ) seconds, where Δf max can represent the maximum supported subcarrier spacing, and Nf It can represent the maximum supported Discrete Fourier Transform (DFT) size. The time intervals of communication resources can be organized according to radio frames each having a specific duration (e.g., 10 milliseconds (ms)). Each radio frame can be identified by a System Frame Number (SFN) (e.g., ranging from 0 to 1023).

[0076] Each frame can include a plurality of consecutively numbered sub - frames or time slots, and each sub - frame or time slot can have the same duration. In some examples, a frame can be divided (e.g., in the time domain) into sub - frames, and each sub - frame can be further divided into a number of time slots. Alternatively, each frame can include a variable number of time slots, and the number of time slots can depend on the sub - carrier spacing. Each time slot can include a number of symbol periods (e.g., depending on the length of the cyclic prefix added before each symbol period). In some wireless communication systems 100, a time slot can be further divided into multiple mini - time slots each containing one or more symbols. Excluding the cyclic prefix, each symbol period can contain one or more (e.g., N f ones) sampling periods. The duration of a symbol period can depend on the sub - carrier spacing or the operating frequency band.

[0077] A sub - frame, time slot, mini - time slot, or symbol can be the smallest scheduling unit (e.g., in the time domain) of the wireless communication system 100 and can be referred to as a Transmission Time Interval (TTI). In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) can be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communication system 100 can be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs)).

[0078] Physical channels can be multiplexed on a carrier according to various techniques. The physical control channel and the physical data channel can be multiplexed on a downlink carrier using, for example, one or more of time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. A control region for the physical control channel (e.g., a control resource set (CORESET)) can be defined by the number of symbol periods and can extend across the system bandwidth of the carrier or a subset of the system bandwidth. One or more control regions (e.g., CORESETs) can be configured for a set of one or more UEs 115. For example, one or more of the UEs 115 can monitor or search for a control region for control information according to one or more search space sets, and each search space set can include one or more control channel candidates in one or more aggregation levels arranged in a cascaded manner. The aggregation level for a control channel candidate can refer to the number of control channel resources (e.g., control channel elements (CCEs)) associated with the encoded information for a control information format with a given payload size. The search space set can include a common search space set configured to send control information to multiple UEs 115 and a UE-specific search space set configured to send control information to a specific UE 115.

[0079] Each base station 105 can provide communication coverage via one or more cells (e.g., macro cells, small cells, hotspots, or other types of cells, or any combination thereof). The term "cell" can refer to a logical communication entity for communicating with a base station 105 (e.g., on a carrier) and can be associated with an identifier (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID), or others) for distinguishing adjacent cells. In some examples, a cell can also refer to a geographic coverage area 110 or a portion of the geographic coverage area 110 (e.g., a sector) on which the logical communication entity operates. The scope of such cells can vary from a smaller area (e.g., a structure, a subset of a structure) to a larger area depending on various factors such as the capabilities of the base station 105. For example, a cell can be or include a building, a subset of a building, or an external space between or overlapping with the geographic coverage area 110, and other examples.

[0080] Macro cells generally cover a relatively large geographical area (e.g., with a radius of several kilometers) and may allow unconstrained access by UEs 115 having a service subscription with the network provider supporting the macro cell. Small cells may be associated with a lower-power base station 105 (compared to macro cells), and small cells may operate in the same or a different (e.g., licensed, unlicensed) frequency band as the macro cell. Small cells may provide unconstrained access to UEs 115 having a service subscription with the network provider, or may provide constrained access to UEs 115 associated with the small cell (e.g., UEs 115 in a closed subscriber group (CSG), UEs 115 associated with users in a home or office). The base station 105 may support one or more cells and may also support communication on one or more cells using one or more component carriers.

[0081] In some examples, a carrier may support multiple cells and may be configured with different cells according to different protocol types (e.g., MTC, NB-IoT, enhanced mobile broadband (eMBB)) that may provide access for different types of devices.

[0082] In some examples, the base station 105 may be mobile and thus provide communication coverage for a mobile geographical coverage area 110. In some examples, different geographical coverage areas 110 associated with different technologies may overlap, but different geographical coverage areas 110 may be supported by the same base station 105. In other examples, overlapping geographical coverage areas 110 associated with different technologies may be supported by different base stations 105. The wireless communication system 100 may include, for example, a heterogeneous network where different types of base stations 105 use the same or different radio access technologies to provide coverage for various geographical coverage areas 110.

[0083] The wireless communication system 100 may support synchronous or asynchronous operation. For synchronous operation, the base stations 105 may have similar frame timings, and transmissions from different base stations 105 may be approximately aligned in time. For asynchronous operation, the base stations 105 may have different frame timings, and in some examples, transmissions from different base stations 105 may not be aligned in time. The techniques described herein may be used for synchronous or asynchronous operation.

[0084] Some UEs 115 (such as MTC or IoT devices) can be low-cost or low-complexity devices and can provide automated communication between machines (e.g., via machine-to-machine (M2M) communication). M2M communication or MTC can refer to data communication technologies that allow devices to communicate with each other or with a base station 105 without human intervention. In some examples, M2M communication or MTC can include communication from devices integrated with sensors or meters to measure or capture information and relay such information to a central server or application, which utilizes the information or presents the information to a person interacting with the application. Some UEs 115 can be designed to collect information or implement automated behavior of machines or other devices. Examples of applications for MTC devices include: smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wilderness survival monitoring, weather and geographical event monitoring, queue management and tracking, remote security sensing, physical access control, and transaction-based commercial charging.

[0085] Some UEs 115 can be configured to operate in power-saving modes, such as half-duplex communication (e.g., a mode that supports one-way communication via transmission or reception but not simultaneous transmission and reception). In some examples, half-duplex communication can be performed at a reduced peak rate. Other power-saving techniques for UEs 115 include entering a deep sleep power-saving mode when not participating in active communication, operating on limited bandwidth (e.g., according to NB communication), or a combination of these techniques. For example, some UEs 115 can be configured for operation using an NB protocol type associated with a defined portion or range within a carrier, within a guard band of the carrier, or outside the carrier (e.g., a set including one or more subcarriers or resource blocks (RBs)).

[0086] The wireless communication system 100 can be configured to support ultra-reliable communication or low-latency communication or various combinations thereof. For example, the wireless communication system 100 can be configured to support ultra-reliable low-latency communication (URLLC) or mission-critical communication. The UE 115 can be designed to support ultra-reliable, low-latency, or critical functions (e.g., mission-critical functions). Ultra-reliable communication can include private communication or group communication and can be supported by one or more mission-critical services (such as mission-critical push-to-talk (MCPTT), mission-critical video (MCVideo), or mission-critical data (MCData)). Support for mission-critical functions can include prioritization of services, and mission-critical services can be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission-critical, and ultra-reliable low-latency can be used interchangeably herein.

[0087] In some examples, the UE 115 may also be able to communicate directly with other UEs 115 over a device-to-device (D2D) communication link 135 (e.g., using peer-to-peer (P2P) or D2D protocols). One or more UEs 115 utilizing D2D communication may be within the geographic coverage area 110 of the base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of the base station 105 or may not be able to receive transmissions from the base station 105 for other reasons. In some examples, a group of UEs 115 communicating via D2D communication may utilize a one-to-many (1:M) system, where each UE 115 transmits to every other UE 115 in the group. In some examples, the base station 105 facilitates the scheduling of resources for D2D communication. In other cases, D2D communication is performed between the UEs 115 without involving the base station 105.

[0088] In some systems, the D2D communication link 135 may be an example of a communication channel (such as a sidelink communication channel) between vehicles (e.g., the UE 115). In some examples, vehicles may communicate using vehicle-to-everything (V2X) communication, vehicle-to-vehicle (V2V) communication, or some combination of these communications. Vehicles may signal information related to traffic conditions, signal scheduling, weather, safety, emergencies, or any other information related to the V2X system. In some examples, vehicles in a V2X system may communicate with roadside infrastructure (such as roadside units), or with the network, or with both, using vehicle-to-network (V2N) communication via one or more network nodes (e.g., the base station 105).

[0089] The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) or a 5G core (5GC), and the EPC or 5GC may include at least one control plane entity that manages access and mobility (e.g., a mobility management entity (MME), an access and mobility management function (AMF)), and at least one user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)). The control plane entity may manage non-access stratum (NAS) functions, such as the mobility, authentication, and bearer management of the UE 115 served by the base station 105 associated with the core network 130. User IP packets may be passed through the user plane entity, which may provide IP address allocation and other functions. The user plane entity may be connected to the network operator IP services 150. The operator IP services 150 may include access to the Internet, an intranet, an IP multimedia subsystem (IMS), or a packet-switched streaming service.

[0090] Some network devices (such as base station 105) may include sub-components, such as access network entity 140, which may be an example of an access node controller (ANC). Each access network entity 140 may communicate with each UE 115 via one or more other access network transmission entities 145, which may be referred to as radio heads, intelligent radio heads, or transmit / receive points (TRPs). Each access network transmission entity 145 may include one or more antenna panels. In some configurations, the various functions of each access network entity 140 or base station 105 may be distributed across various network devices (e.g., radio heads and ANCs) or combined into a single network device (e.g., base station 105).

[0091] The wireless communication system 100 may operate using one or more frequency bands (in some examples, in the range of 300 megahertz (MHz) to 300 gigahertz (GHz)). Generally, the 300 MHz to 3 GHz division is known as the ultra-high frequency (UHF) division or the decimeter band because the wavelengths are in the range of approximately one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features, but these waves can sufficiently penetrate various structures for macrocells to provide service to UEs 115 located indoors. Compared to transmissions using smaller frequencies and longer waves in the high frequency (HF) or very high frequency (VHF) portions of the spectrum below 300 MHz, UHF wave transmissions may be associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers).

[0092] The wireless communication system 100 may also operate in the super-high frequency (SHF) division using frequency bands from 3 GHz to 30 GHz (also known as the centimeter band) or in the extremely high frequency (EHF) division of the spectrum (e.g., from 30 GHz to 300 GHz) (also known as the millimeter band). In some examples, the wireless communication system 100 may support millimeter wave (mmW) communication between the UE 115 and the base station 105, and the EHF antennas of the corresponding devices may be smaller and more closely spaced than UHF antennas. In some examples, this may facilitate the use of antenna arrays within the devices. However, the propagation of EHF transmissions may experience even greater atmospheric attenuation and shorter ranges than SHF or UHF transmissions. The techniques disclosed herein may be employed across transmissions using one or more different frequency divisions, and the use of frequency bands designated across these frequency divisions may vary by country or regulatory body.

[0093] The wireless communication system 100 can utilize both licensed and unlicensed radio frequency bands. For example, the wireless communication system 100 can adopt licensed-assisted access (LAA), LTE-unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band (such as the 5 GHz industrial, scientific, and medical (ISM) band). When operating in an unlicensed radio frequency band, devices (such as base station 105 and UE 115) can adopt carrier sensing for collision detection and avoidance. In some examples, the operation in the unlicensed band can be based on a carrier aggregation configuration (such as LAA) in coordination with a component carrier operating in a licensed band. The operation in the unlicensed spectrum can include downlink transmission, uplink transmission, P2P transmission, or D2D transmission, etc.

[0094] Base station 105 or UE 115 can be equipped with multiple antennas, which can be used to adopt technologies such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communication, or beamforming. The antennas of base station 105 or UE 115 can be located within one or more antenna arrays or antenna panels that can support MIMO operation or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays can be co-located at an antenna assembly (such as an antenna tower). In some examples, the antennas or antenna arrays associated with base station 105 can be located at different geographical locations. Base station 105 can have an antenna array that has several rows and columns of antenna ports for beamforming that base station 105 can use to support communication with UE 115. Similarly, UE 115 can have one or more antenna arrays that can support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel can support radio frequency beamforming for signals transmitted via the antenna ports.

[0095] Base station 105 or UE 115 can use MIMO communication to utilize multipath signal propagation and improve spectral efficiency by transmitting or receiving multiple signals via different spatial layers. Such technologies can be referred to as spatial multiplexing. For example, the transmitting device can transmit multiple signals via different antennas or different combinations of antennas. Similarly, the receiving device can receive multiple signals via different antennas or different combinations of antennas. Each of the multiple signals can be referred to as a separate spatial stream and can carry bits associated with the same data stream (such as the same codeword) or different data streams (such as different codewords). Different spatial layers can be associated with different antenna ports for channel measurement and reporting. MIMO technologies include single-user MIMO (SU-MIMO), where multiple spatial layers are transmitted to the same receiving device; and multi-user MIMO (MU-MIMO), where multiple spatial layers are transmitted to multiple devices.

[0096] Beamforming (which may also be referred to as spatial filtering, directional transmission, or directional reception) is a signal processing technique that can be used at a transmitting device or a receiving device (e.g., base station 105, UE 115) to shape or direct an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming can be achieved by combining signals communicated via the antenna elements of an antenna array such that some signals propagating in a particular orientation relative to the antenna array experience constructive interference while other signals experience destructive interference. The adjustment of the signals communicated via the antenna elements can include the transmitting device or the receiving device applying an amplitude offset, a phase offset, or both to the signals carried via the antenna elements associated with the device. The adjustment associated with each antenna element can be defined by a set of beamforming weights associated with a particular orientation (e.g., relative to the antenna array of the transmitting device or the receiving device, or relative to some other orientation).

[0097] The base station 105 or the UE 115 can use beam sweeping techniques as part of a beamforming operation. For example, the base station 105 can use multiple antennas or antenna arrays (e.g., antenna panels) to perform beamforming operations for directional communication with the UE 115. Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) can be transmitted by the base station 105 multiple times in different directions. For example, the base station 105 can transmit signals according to different sets of beamforming weights associated with different transmission directions. Transmissions in different beam directions can be used (e.g., by the transmitting device such as the base station 105 or the receiving device such as the UE 115) to identify the beam direction used by the base station 105 for later transmission or reception.

[0098] Some signals (such as data signals associated with a particular receiving device) can be transmitted by the base station 105 in a single beam direction (e.g., the direction associated with the receiving device such as the UE 115). In some examples, the beam direction associated with a transmission in a single beam direction can be determined based on signals transmitted in one or more beam directions. For example, the UE 115 can receive one or more signals transmitted by the base station 105 in different directions and can report to the base station 105 an indication of the signal received by the UE 115 with the highest signal quality or other acceptable signal quality.

[0099] In some examples, transmissions made by a device (e.g., by base station 105 or UE 115) may be performed using multiple beam directions, and the device may use a combination of digital precoding or radio frequency beamforming to generate a combined beam for transmission (e.g., from base station 105 to UE 115). UE 115 may report feedback indicating precoding weights for one or more beam directions, and the feedback may correspond to a configured number of beams across the system bandwidth or one or more subbands. Base station 105 may transmit reference signals that may or may not be precoded (e.g., cell-specific reference signal (CRS), channel state information reference signal (CSI-RS)). UE 115 may provide feedback for beam selection, which may be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., multi-panel type codebook, linear combination type codebook, port selection type codebook). Although these techniques are described with reference to signals transmitted by base station 105 in one or more directions, UE 115 may use similar techniques for transmitting signals multiple times in different directions (e.g., for identifying beam directions used by UE 115 for subsequent transmissions or receptions) or for transmitting signals in a single direction (e.g., for transmitting data to a receiving device).

[0100] A receiving device (e.g., UE 115) may attempt multiple receive configurations (e.g., directional listening) when receiving various signals from base station 105, such as synchronization signals, reference signals, beam selection signals, or other control signals. For example, the receiving device may attempt multiple receive directions by receiving via different antenna subarrays, processing received signals according to different antenna subarrays, receiving according to different receive beamforming weight sets (e.g., different directional listening weight sets) applied to signals received at multiple antenna elements of an antenna array, or processing received signals according to different receive beamforming weight sets applied to signals received at multiple antenna elements of an antenna array, any of which may be referred to as "listening" according to different receive configurations or receive directions. In some examples, the receiving device may use a single receive configuration to receive along a single beam direction (e.g., when receiving a data signal). The single receive configuration may be aligned in a beam direction determined based on listening according to different receive configuration directions (e.g., a beam direction determined to have the highest signal strength, highest signal-to-noise ratio (SNR), or other acceptable signal quality based on listening according to multiple beam directions).

[0101] The wireless communication system 100 can be a packet-based network that operates according to a layered protocol stack. On the user plane, the communication of the bearer or packet data convergence protocol (PDCP) layer can be IP-based. The radio link control (RLC) layer can perform packet segmentation and reassembly for communication on logical channels. The media access control (MAC) layer can perform priority handling and multiplex logical channels into transport channels. The MAC layer can also use error detection techniques, error correction techniques, or both to support retransmissions at the MAC layer to improve link efficiency. On the control plane, the radio resource control (RRC) protocol layer can provide the establishment, configuration, and maintenance of the RRC connection that supports the radio bearers for user plane data between the UE 115 and the base station 105 or the core network 130. On the physical layer, the transport channels can be mapped to physical channels.

[0102] The UE 115 and the base station 105 can support retransmissions of data to increase the likelihood that the data is successfully received. Hybrid automatic repeat request (HARQ) feedback is a technique for increasing the likelihood of correctly receiving data on the communication link 125. HARQ can include a combination of error detection (e.g., using cyclic redundancy check (CRC)), forward error correction (FEC), and retransmission (e.g., automatic repeat request (ARQ)). HARQ can improve the throughput of the MAC layer in poor radio conditions (e.g., low signal-to-noise ratio conditions). In some examples, the device can support simultaneous slot HARQ feedback, where the device can provide HARQ feedback for data received in previous symbols in a particular slot in that slot. In other cases, the device can provide HARQ feedback in a subsequent slot or according to some other time interval.

[0103] The wireless communication system 100 can also include one or more satellites 120 or other non-terrestrial devices. The satellite 120 can communicate with the base station 105 (also referred to as the gateway in the non-terrestrial network) and the UE 115 (or other high-altitude or terrestrial communication devices). The satellite 120 can be any suitable type of communication satellite configured to relay communication between different end nodes in the wireless communication system. The satellite 120 can be an example of a space satellite, a balloon, a spacecraft, an aircraft, a drone, an unmanned aerial vehicle, or any combination thereof. In some examples, the satellite 120 can be in a geostationary or geosynchronous orbit, a low Earth orbit, or a medium Earth orbit. The satellite 120 can be a multi-beam satellite configured to serve multiple service beam coverage areas in a predefined geographical service area. The satellite 120 can be at any distance from the Earth's surface.

[0104] In some cases, a cell may be provided or established by satellite 120 as part of a non-terrestrial network. In some cases, satellite 120 may perform the functions of base station 105, acting as a bent pipe satellite, a regenerative satellite, or a combination thereof. In other cases, satellite 120 may be an example of an intelligent satellite or a satellite with intelligence. For example, an intelligent satellite may be configured to perform more functions than a regenerative satellite (e.g., may be configured to perform specific algorithms in addition to the algorithms used in a regenerative satellite, or may be configured to be reprogrammed, etc.). A bent pipe transponder or satellite may be configured to receive signals from a ground station and transmit those signals to different ground stations. In some cases, a bent pipe transponder or satellite may amplify the signals or convert from an uplink frequency to a downlink frequency. A regenerative transponder or satellite may be configured to relay signals like a bent pipe transponder or satellite, but may also use on-board processing to perform other functions. Examples of those other functions may include demodulating received signals, decoding received signals, re-encoding signals to be transmitted, modulating signals to be transmitted, or a combination thereof. For example, a bent pipe satellite (e.g., satellite 120) may receive signals from base station 105 and relay the signal to UE 115 or base station 105, and vice versa.

[0105] Some wireless communication networks (such as NB-IoT networks) may support various synchronization techniques to facilitate communication between devices in the network. One such technique employs the use of a channel raster, which may be an index indicating the frequency positions that UE 115 or satellite 120 may use to search for an anchor carrier for initial synchronization with wireless communication system 100.

[0106] In a terrestrial NB-IoT deployment, UE 115 may estimate the frequency of a carrier and an initial frequency estimation error associated with the initial frequency estimate. In most examples, the initial frequency estimation error is small enough such that the UE can accurately estimate the frequency of the carrier, and the UE may synchronize with a terrestrial NB-IoT cell using the identified synchronization procedure. However, in a non-terrestrial deployment, due to higher operating frequencies, Doppler shift effects, and other factors, the initial frequency estimation error for UE 115 may be much larger. Thus, a UE in a non-terrestrial network may incorrectly estimate the frequency of an NB-IoT carrier and may attempt to connect to an NB cell using the incorrectly estimated frequency.

[0107] The network can implement several synchronization techniques to increase the likelihood that the UE 115 can effectively connect to the correct NB cell and correctly estimate the frequency associated with the NB cell. In one example, the frequency spacing associated with the channel raster for the non-terrestrial NB-IoT network can be increased such that the spacing between the effective NB-IoT anchor carrier positions is increased relative to those in the terrestrial network. In another example, the UE 115 can receive an ARFCN indicating the frequency for the cell and can use the ARFCN to determine whether the frequency supported by the NB cell is the same as or different from the frequency that the UE 115 expects to be transmitted by the NB cell. In another example, the non-terrestrial network can limit the number of NB cell IDs available for each ARFCN based on an effective mapping between the NB cell ID and the ARFCN.

[0108] Figure 2 An example of a wireless communication system 200 that supports downlink synchronization for non-terrestrial wireless communication in accordance with aspects of the present disclosure is illustrated. In some examples, the wireless communication system 200 can implement aspects of the wireless communication system 100. For example, the wireless communication system 200 can be associated with non-terrestrial NB-IoT communication between a base station 105-a and a non-terrestrial UE 115-a (such as a satellite 120-a), where each of the base station 105-a and the non-terrestrial UE 115-a can be an example of the base station 105, UE 115, and satellite 120 Figure 1 described.

[0109] Some wireless communication networks (such as NB-IoT networks) can support various synchronization techniques to facilitate communication between devices in the network. One such technique employs the use of a channel raster, which can indicate an index of frequency positions that the UE 115-a can use to search for anchor carriers (e.g., initial synchronization NB-IoT resource blocks) during cell capture. More specifically, the channel raster can provide a range of frequency positions of NB-IoT anchor carriers that carry downlink synchronization signals or channels (e.g., NB-IoT reference signal (NRS), NB-IoT primary synchronization signal (NPSS), NB-IoT secondary synchronization signal (NSSS), NB-IoT physical broadcast channel (NPBCH), NB-IoT physical downlink shared channel (NPDSCH), or NB-IoT physical downlink control channel (NPDCCH)), and the 115-a can use this range to synchronize with the NB-IoT cell 205. In the example of a 100 kHz channel raster, the NB-IoT anchor carriers can be located at resource block positions according to the channel raster (e.g., one anchor carrier per 100 kHz).

[0110] The channel raster can be associated with a given raster offset (e.g., + / -7.5 kHz for a 100 kHz raster) such that the NB-IoT anchor carrier is at a frequency that differs from the raster by up to the raster offset (e.g., expressed as M×100 kHz + R 偏移 ). The raster offset can account for possible errors in the frequency estimation performed by UE 115-a or possible errors in the placement of NB-IoT frequency carriers (e.g., NB-IoT anchor carriers or non-anchor carriers). Additionally, the raster offset may be different for different NB-IoT systems (e.g., up to 7.5 kHz for in-band or guard band deployments, and up to 0 kHz for stand-alone deployments).

[0111] In a terrestrial NB-IoT deployment, UE 115-a can estimate the frequency of the carrier during the initial synchronization process and the initial frequency estimation error associated with the initial frequency estimate. In most examples, the initial frequency estimation error is small enough such that UE 115-a can accurately estimate the frequency of the carrier. After estimating the frequency, UE 115-a can successfully "lock" to the NB-IoT cell (e.g., establish a connection to the NB-IoT cell). In other words, the actual frequency estimated by UE 115-a for the cell plus the raster offset and the initial frequency error for the terrestrial system can be small enough such that UE 115-a does not mistake the operating frequency of the cell for the operating frequency of a different cell transmitting at a different frequency. Thus, in most terrestrial systems, UE 115-a can accurately estimate the carrier frequency and can synchronize with or otherwise establish communication with the terrestrial NB cell.

[0112] However, in non-terrestrial deployments (such as in wireless communication system 200), the initial frequency estimation error for UE 115-a can be much larger due to the higher operating frequencies, Doppler effects, and movement of the UE in the non-terrestrial network. For example, UE 115-a can be a non-terrestrial UE (such as satellite 120-a (or UE 115-a located at satellite 120-a)), or any other non-terrestrial device that establishes communication with NB cell 205. Based on the characteristics of non-terrestrial communication (e.g., longer distances between devices, orbital motion, interference, Doppler effects), UE 115-a may incorrectly estimate the frequency of the NB IoT carrier and may attempt to lock to the NB cell using the incorrectly estimated frequency. Subsequently, UE 115-a may expect to receive communication from base station 105-a at an incorrectly estimated frequency that is different from the frequency used by base station 105-a. Such a mismatch between the frequency that UE 115-a expects to receive and the actual frequency used by base station 105-a on NB cell 205 can cause UE 115-a to lose synchronization with base station 105-a and, in some cases, drop the communication on NB cell 205.

[0113] The various differences between non-terrestrial networks and terrestrial networks can further increase the ability of UE 115-a to accurately estimate the NB-IoT carrier frequency during the synchronization procedure. For example, the initial frequency error estimated by UE 115-a in a non-terrestrial network may be greater than the error assumed by a terrestrial network (e.g., a 20 ppm error). Additionally, non-terrestrial or satellite-based communication can operate in the "S" band or higher bands, which may be associated with frequencies significantly higher than terrestrial NB-IoT carrier frequencies. These higher operating frequencies may increase the likelihood of errors. For example, in the S-band operating mode, a UE in a non-terrestrial network may have an initial frequency error of up to 47.5 kHz (e.g., (20 ppm error) × (2 GHz carrier frequency) + (7.5 kHz offset present in the system)), which may be greater than the 25.5 kHz initial channel frequency offset of a terrestrial system operating at a carrier frequency of 900 MHz.

[0114] To improve communication efficiency and effectively mitigate the effects of larger errors and larger initial channel frequency offsets in non-terrestrial networks, the network can implement several different techniques to increase the likelihood that UE 115-a can effectively lock to the correct NB cell and estimate the correct frequency associated with the NB cell.

[0115] In one example, the frequency spacing associated with the channel raster of a non-terrestrial NB-IoT network can be increased such that the spacing between effective NB-IoT anchor carrier positions is increased relative to those in a terrestrial network. For example, the non-terrestrial network can have an increased channel raster such that UE 115-a searches for NB-IoT anchor carriers according to a larger frequency spacing (e.g., the NB-IoT anchor carriers can be located at 200 kHz as compared to every 100 kHz for a terrestrial system). The channel raster for the non-terrestrial network can be several different values and can be configured or changed based on various network characteristics. Additionally, the channel raster offset can be increased proportionally to the increase in the channel raster. Increasing the channel raster can account for the larger channel frequency offsets and initial frequency errors associated with communications in a non-terrestrial network.

[0116] In another example, UE 115-a can establish communication with NB cell 205 and can receive MIB 210 from base station 105-a. In some examples, the MIB can be transmitted in an NB downlink channel or in an SIB received after UE 115-a locks onto cell 205. UE 115-a can identify information in the MIB, such as an indication of the true value of the NB-IoT anchor carrier frequency associated with cell 205. For example, the MIB or SIB can include an ARFCN indicating the frequency for the cell. The MIB or SIB can include the full ARFCN or a portion of the ARFCN. For example, the MIB can include some of the least significant bits (LSBs) of the ARFCN, which can indicate the NB-IoT carrier frequency of cell 205.

[0117] In some examples, UE 115-a can use the ARFCN to determine that the frequency transmitted by base station 105-a in cell 205 is different from the operating frequency expected by UE 115-a (based on an initial frequency estimate for the cell). In some cases, if UE 115-a determines such a frequency mismatch, UE 115-a can disconnect from the cell and attempt to synchronize with a different NB cell.

[0118] In another example, the frequency location indicated by an ARFCN at which a given NB cell ID can be located in a non-terrestrial network can be restricted relative to a terrestrial network. For example, the non-terrestrial network can restrict the numbering of NB cell IDs available for each ARFCN. For example, even-numbered ARFCNs can be associated with even-numbered NB cell IDs, while odd-numbered ARFCNs can be associated with odd-numbered cell IDs. In such examples, if UE 115-a locks to an odd ARFCN but measures an even carrier position, UE 115-a can determine that UE 115-a has incorrectly measured the frequency of the cell and can disconnect from the cell. Different mappings between ARFCNs and NB cell IDs can also be implemented. The mapping between ARFCNs and NB cell IDs can increase the network's resilience to frequency offsets and can increase the ability of UE115-a to select the correct cell based on an initial frequency estimate in the non-terrestrial network.

[0119] Figure 3 An example of process flow 300 that supports downlink synchronization for non-terrestrial wireless communications in accordance with aspects of the present disclosure is illustrated. In some examples, process flow 300 can implement aspects of wireless communication system 100. For example, process flow 300 can be associated with non-terrestrial NB-IoT communication between base station 105-b and non-terrestrial UE 115-b (such as a satellite), and base station 105-b and non-terrestrial UE 115-b can be examples of base station 105 and UE 115 as Figure 1 and 2 described. In some examples, base station 105-b and UE 115-b can be located in an NB cell that serves one or more NB-IoT-specific UEs. In the following description of process flow 300, the operations between base station 105-b and non-terrestrial UE 115-b as shown can be performed in a different order or at different times. Some operations can also be omitted from process flow 300, and other operations can be added to process flow 300.

[0120] At 305, base station 105-b can identify that UE 115-b is associated with the non-terrestrial network and can determine a synchronization procedure specific to the non-terrestrial network. Base station 105-b can transmit an indication of the first synchronization procedure to UE 115-b.

[0121] At 310, UE 115-b may identify a first synchronization procedure specific to a non-terrestrial network, which may be different from a second synchronization procedure specific to a terrestrial network. For example, UE 115-b may identify a first channel raster on a frequency specific to a non-terrestrial network and different from a second channel raster on a frequency specific to other terrestrial networks. For example, the first channel raster for a non-terrestrial network may have an increased NB-IoT cell carrier spacing relative to the second channel raster for a terrestrial network.

[0122] UE 115-b may identify a set including one or more frequency positions of at least one NB-IoT anchor carrier based on the frequency position of the first channel raster, and may monitor the set including one or more frequency positions of the anchor carrier. Once UE 115-b receives an NB-IoT anchor carrier, UE 115-b may identify one or more downlink synchronization signals (e.g., NPS, NSSS, etc.) for synchronizing with the NB cell according to the first synchronization procedure.

[0123] At 320, UE 115-b may identify an NB cell associated with the NB-IoT network for synchronization, and may synchronize with the identified cell at 325 based on the identified synchronization procedure.

[0124] In some examples, UE 115-b may receive an information block specific to a non-terrestrial network (e.g., MIB or SIB), which includes an indication of the true value of a first NB-IoT anchor carrier associated with the NB cell. For example, an indication of the true value of the first NB-IoT anchor carrier frequency may be indicated in at least a portion of the ARFCN for the NB cell. The ARFCN may be partially or fully included in the MIB or SIB. In some cases, several LSBs of the ARFCN may be included.

[0125] UE 115-b may compare the measured value of the first NB-IoT carrier frequency with the true value of the first NB-IoT anchor carrier, and may selectively maintain or discard the connection with the cell based on this comparison. In some cases, UE 115-b may determine that the measured value of the first NB-IoT carrier frequency matches the true value of the NB-IoT anchor carrier frequency of the NB cell, and UE 115-b may maintain the connection with the NB cell based on the measured carrier frequency matching the true value of the NB-IoT anchor carrier frequency. In some other cases, UE 115-b may determine that the measured value of the first NB-IoT carrier frequency is different from the true value of the NB-IoT anchor carrier frequency of the NB cell, and UE 115-b may discard the connection with the NB cell based on the measured carrier frequency being different from the true value of the NB-IoT anchor carrier frequency.

[0126] In some examples, UE 115-b may identify a valid mapping between an ARFCN and an NB cell ID associated with an NB cell, where synchronization with the NB cell is based on the valid mapping. For example, UE 115-b may determine that a first set of one or more NB cell IDs (e.g., even-valued NB cell IDs) is associated with a first ARFCN (e.g., even-valued ARFCN), and may determine that a second set of one or more NB cell IDs (e.g., odd-valued NB cell IDs) is associated with a second ARFCN (e.g., odd-valued ARFCN).

[0127] In some examples, UE 115-b may identify the mapping as a number for a candidate set of ARFCN and cell IDs. For example, odd ARFCNs may be mapped to odd cell IDs, and even ARFCNs may be mapped to even cell IDs, although other valid mappings between cell IDs and ARFCNs are possible. In a case where UE 115-b determines (e.g., from NPSS and NSSS) that the NB cell ID is odd, but the estimated carrier frequency corresponds to an even ARFCN, UE 115-b may consider the pair (cell ID, estimated ARFCN) invalid and may disconnect from the cell.

[0128] At 330, UE 115-b may synchronize with the NB cell based on a synchronization procedure. For example, UE 115-b may establish communication based on receiving one or more NB synchronization signals associated with a first synchronization procedure. In some cases, UE 115-b may optionally establish communication based on determining that UE 115-b has accurately determined the frequency associated with the NB cell.

[0129] Figure 4 Block diagram 400 shows a device 405 that supports downlink synchronization for non-terrestrial wireless communications in accordance with aspects of the present disclosure. Device 405 may be an example of aspects of UE 115 as described herein. Device 405 may include a receiver 410, a communication manager 415, and a transmitter 420. Device 405 may also include a processor. Each of these components may be in communication with each other (e.g., via one or more buses).

[0130] The receiver 410 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to downlink synchronization for non-terrestrial wireless communications, etc.). The information may be passed to other components of device 405. The receiver 410 may be a reference to Figure 7Examples of aspects of the transceiver 720 described. The receiver 410 may utilize a single antenna or a collection of one or more antennas.

[0131] The communication manager 415 may identify a first synchronization procedure specific to a non-terrestrial network and different from a second synchronization procedure specific to a terrestrial network; synchronize with the identified cell by performing the identified synchronization procedure; and identify a cell associated with the non-terrestrial network for synchronization with the UE. The communication manager 415 may be an example of aspects of the communication manager 710 described herein.

[0132] The communication manager 415 or its sub-components may be implemented in hardware, code executed by a processor (e.g., software or firmware), or any combination thereof. If implemented in code executed by a processor, the functions of the communication manager 415 or its sub-components may be performed by a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in this disclosure.

[0133] The communication manager 415 or its sub-components may be physically located at various locations, including being distributed such that portions of the functionality are implemented by one or more physical components at different physical locations. In some examples, in accordance with various aspects of the present disclosure, the communication manager 415 or its sub-components may be separate and distinct components. In some examples, in accordance with various aspects of the present disclosure, the communication manager 415 or its sub-components may be combined with one or more other hardware components, including but not limited to input / output (I / O) components, transceivers, network servers, another computing device, one or more other components described in this disclosure, or combinations thereof.

[0134] The transmitter 420 may transmit signals generated by other components of the device 405. In some examples, the transmitter 420 may be co-located with the receiver 410 in a transceiver module. For example, the transmitter 420 may be an example of aspects of the transceiver 720 described with reference to Figure 7 Examples of aspects of the transceiver 720 described. The transmitter 420 may utilize a single antenna or a collection of one or more antennas.

[0135] Figure 5 Block diagram 500 showing a device 505 in accordance with aspects of the present disclosure supporting downlink synchronization for non-terrestrial wireless communication. The device 505 may be an example of aspects of the device 405 or UE 115 described herein. The device 505 may include a receiver 510, a communication manager 515, and a transmitter 535. The device 505 may also include a processor. Each of these components may be in communication with each other (e.g., via one or more buses).

[0136] The receiver 510 can receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to downlink synchronization for non-terrestrial wireless communications, etc.). The information can be passed to other components of the device 505. The receiver 510 can be an example of aspects of the transceiver 720 described with reference to Figure 7 The receiver 510 can utilize a single antenna or a set of one or more antennas.

[0137] The communication manager 515 can be an example of aspects of the communication manager 415 described herein. The communication manager 515 can include an NB-IoT synchronization component 520, a cell identification component 525, and a connection establishment component 530. The communication manager 515 can be an example of aspects of the communication manager 710 described herein.

[0138] The NB-IoT synchronization component 520 can identify a first synchronization procedure specific to a non-terrestrial network and different from a second synchronization procedure specific to a terrestrial network, and synchronize with the identified cell by executing the identified synchronization procedure.

[0139] The cell identification component 525 can identify a cell associated with the non-terrestrial network for synchronization with the UE.

[0140] In some cases, the connection establishment component 530 can establish a connection with the cell or can otherwise synchronize with the cell.

[0141] The transmitter 535 can transmit signals generated by other components of the device 505. In some examples, the transmitter 535 can be co-located with the receiver 510 in a transceiver module. For example, the transmitter 535 can be an example of aspects of the transceiver 720 described with reference to Figure 7 The transmitter 535 can utilize a single antenna or a set of one or more antennas.

[0142] In some examples, the communication manager 515 can be implemented as an integrated circuit or chipset for a mobile device modem, and the receiver 510 and transmitter 520 can be implemented as analog components (e.g., amplifiers, filters, antennas, etc.) coupled to the mobile device modem to enable wireless transmission and reception.

[0143] The communication manager 515, as described herein, may be implemented to achieve one or more potential advantages. Various implementations may enable the communication manager 515 to accurately estimate the frequency of an NB-IoT carrier and synchronize with an NB cell based on the estimated frequency. At least one implementation may enable the communication manager 515 to effectively determine a synchronization procedure and a channel raster specific to a non-terrestrial network and implement channel monitoring based on the non-terrestrial specific channel raster. In some other implementations, the communication manager 515 may be able to effectively determine that the communication manager 515 has connected to an incorrect NB-IoT cell and may disconnect based on that determination.

[0144] Based on implementing the synchronization techniques as described herein, one or more processors of the device 505 (e.g., one or more of the processors in the control receiver 510, communication manager 515, and transmitter 520 or associated therewith) may reduce the number of instances in which the device incorrectly estimates the NB-IoT carrier frequency associated with an NB cell. Additionally, the synchronization techniques may reduce latency and improve communication efficiency in the network by limiting unsuccessful synchronization attempts. Further, these techniques may allow the device to more effectively identify whether the device has incorrectly locked onto an NB cell.

[0145] Figure 6 Block diagram 600 shows a communication manager 605 that supports downlink synchronization for non-terrestrial wireless communications in accordance with aspects of the present disclosure. The communication manager 605 may be an example of aspects of the communication manager 415, communication manager 515, or communication manager 710 described herein. The communication manager 605 may include an NB-IoT synchronization component 610, a cell identification component 615, a connection establishment component 620, an NB-IoT channel raster component 625, an anchor carrier monitoring component 630, an information block reception component 635, a frequency comparison component 640, an ARFCN identification component 645, an ARFCN and cell ID mapping component 650, and an NB-IoT synchronization signal receiver 655. Each of these modules may communicate directly or indirectly with each other (e.g., via one or more buses).

[0146] The NB-IoT synchronization component 610 may identify a first synchronization procedure specific to a non-terrestrial network and different from a second synchronization procedure specific to a terrestrial network. The cell identification component 615 may identify a cell associated with the non-terrestrial network for synchronization with the UE.

[0147] In some examples, the NB-IoT synchronization component 610 may synchronize with the identified cell by performing the identified synchronization procedure. In some cases, the cell is an NB cell serving one or more NB (narrowband) Internet of Things (IoT) UEs.

[0148] The connection establishment component 620 can establish a connection with a cell or synchronize with the cell in other ways based on the identified synchronization procedure.

[0149] The frequency comparison component 640 can compare the first carrier frequency with the true value of the carrier frequency of the cell. In some examples, the frequency comparison component 640 can determine that the first carrier frequency matches the true value of the carrier frequency of the cell. In some examples, the frequency comparison component 640 can determine that the first carrier frequency is different from the true value of the carrier frequency of the cell.

[0150] In some examples, the connection establishment component 620 can selectively maintain or discard the connection with the cell based on the comparison. For example, in some examples, the connection establishment component 620 can maintain the connection with the cell based on the first carrier frequency matching the true value of the carrier frequency. In some examples, the connection establishment component 620 can discard the connection with the cell based on the first carrier frequency being different from the true value of the carrier frequency.

[0151] The NB-IoT channel raster component 625 can identify a first channel raster on a frequency specific to the non-terrestrial network and different from a second channel raster on a frequency specific to the terrestrial network. In some cases, the first channel raster can include a cell carrier spacing that is increased in frequency relative to the second channel raster.

[0152] The anchor carrier monitoring component 630 can identify a set including one or more frequency positions of at least one anchor carrier according to the first channel raster. In some examples, the anchor carrier monitoring component 630 can monitor the at least one anchor carrier for one or more downlink synchronization signals, where synchronization with the cell can be based on the one or more downlink synchronization signals.

[0153] The information block receiving component 635 can receive an information block specific to the non-terrestrial network, the information block including an indication of the true value of the carrier frequency associated with the cell. In some cases, the information block includes the MIB. In some cases, the true value of the first carrier frequency can further include at least a portion of the ARFCN for the cell. In some cases, the information block can be an SIB including the ARFCN. In some cases, the MIB can include a set of one or more least significant bits of the ARFCN. The ARFCN and cell ID mapping component 650 can identify a valid mapping between the ARFCN and the cell ID associated with the cell. In some examples, the mapping component 650 can synchronize with the NB cell based on the valid mapping.

[0154] The NB-IoT synchronization signal receiver 655 can receive one or more synchronization signals associated with a first synchronization procedure, where the one or more synchronization signals include narrowband synchronization signals.

[0155] Figure 7 FIG. shows a diagram of a system 700 including a device 705 that supports downlink synchronization for non-terrestrial wireless communication according to aspects of the present disclosure. The device 705 can be an example of the device 405, the device 505, or the UE 115 described herein or include components of the above devices. The device 705 can include components for two-way voice and data communication, which include components for transmitting and receiving communication, including a communication manager 710, an I / O controller 715, a transceiver 720, an antenna 725, a memory 730, and a processor 740. These components can be in electronic communication via one or more buses (e.g., bus 745).

[0156] The communication manager 710 can identify a first synchronization procedure specific to a non-terrestrial network and different from a second synchronization procedure specific to a terrestrial network; synchronize with the identified cell by executing the identified synchronization procedure; and identify a cell associated with the non-terrestrial network for synchronizing with the UE.

[0157] The I / O controller 715 can manage the input and output signals of the device 705. The I / O controller 715 can also manage peripheral devices not integrated into the device 705. In some cases, the I / O controller 715 can represent a physical connection or port to an external peripheral device. In some cases, the I / O controller 715 can utilize an operating system, such as or another known operating system. In other cases, the I / O controller 715 can represent or interact with a modem, a keyboard, a mouse, a touch screen, or a similar device. In some cases, the I / O controller 715 can be implemented as part of a processor. In some cases, a user can interact with the device 715 via the I / O controller 705 or via a hardware component controlled by the I / O controller 715.

[0158] The transceiver 720 can perform two-way communication via one or more antennas, wired or wireless links, as described herein. For example, the transceiver 720 can represent a wireless transceiver and can perform two-way communication with another wireless transceiver. The transceiver 720 can also include a modem to modulate packets and provide the modulated packets to the antenna for transmission, and to demodulate packets received from the antenna.

[0159] In some cases, the wireless device can include a single antenna 725. However, in some cases, the device can have more than one antenna 725, which can be capable of concurrently transmitting or receiving multiple wireless transmissions.

[0160] The memory 730 may include RAM and ROM. The memory 730 may store computer-readable, computer-executable code 735 including instructions that, when executed, cause the processor to perform the various functions described herein. In some instances, the memory 730 may in particular include a basic input / output system (BIOS) that may control basic hardware or software operations, such as interactions with peripheral components or devices.

[0161] The processor 740 may include intelligent hardware devices (e.g., general-purpose processors, DSPs, CPUs, microcontrollers, ASICs, FPGAs, programmable logic devices, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some instances, the processor 740 may be configured to operate a memory array using a memory controller. In other instances, the memory controller may be integrated into the processor 740. The processor 740 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 730) to cause the device 705 to perform various functions (e.g., support functions or tasks for downlink synchronization for non-terrestrial wireless communications).

[0162] The code 735 may include instructions for implementing aspects of the present disclosure, including instructions for supporting wireless communications. The code 735 may be stored in a non-transitory computer-readable medium, such as system memory or other types of memory. In some instances, the code 735 may not be directly executable by the processor 740 but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0163] Figure 8 Block diagram 800 illustrates a device 805 in accordance with aspects of the present disclosure that supports downlink synchronization for non-terrestrial wireless communications. The device 805 may be an example of aspects of the base station 105 as described herein. The device 805 may include a receiver 810, a communication manager 815, and a transmitter 820. The device 805 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

[0164] The receiver 810 may receive information, such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to downlink synchronization for non-terrestrial wireless communications, etc.). The information may be passed to other components of the device 805. The receiver 810 may be an example of aspects of the transceiver 1120 described with reference to Figure 11 The receiver 810 may utilize a single antenna or an ensemble of one or more antennas.

[0165] The communication manager 815 may identify a first synchronization procedure specific to a non-terrestrial network and different from a second synchronization procedure specific to a terrestrial network; identify UEs associated with the non-terrestrial network for synchronization with a cell associated with the base station; and synchronize with the identified UEs by performing the identified synchronization procedure. The communication manager 815 may be an example of aspects of the communication manager 1110 as described herein.

[0166] The communication manager 815 or its sub-components may be implemented in hardware, code executed by a processor (e.g., software or firmware), or any combination thereof. If implemented in code executed by a processor, the functions of the communication manager 815 or its sub-components may be performed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC), an FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in this disclosure.

[0167] The communication manager 815 or its sub-components may be physically located at various locations, including being distributed such that portions of the functionality are implemented by one or more physical components at different physical locations. In some examples, in accordance with aspects of the present disclosure, the communication manager 815 or its sub-components may be separate and distinct components. In some examples, in accordance with aspects of the present disclosure, the communication manager 815 or its sub-components may be combined with one or more other hardware components, including but not limited to input / output (I / O) components, transceivers, network servers, another computing device, one or more other components described in this disclosure, or combinations thereof.

[0168] The transmitter 820 may transmit signals generated by other components of the device 805. In some examples, the transmitter 820 may be co-located with the receiver 810 in a transceiver module. For example, the transmitter 820 may be an example of aspects of the transceiver 1120 described with reference to Figure 11 The transmitter 820 may utilize a single antenna or a collection of one or more antennas.

[0169] Figure 9 Block diagram 900 illustrates a device 905 in accordance with aspects of the present disclosure that supports downlink synchronization for non-terrestrial wireless communications. The device 905 may be an example of aspects of the device 805 or the base station 105 as described herein. The device 905 may include a receiver 910, a communication manager 915, and a transmitter 930. The device 905 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

[0170] The receiver 910 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to downlink synchronization for non-terrestrial wireless communications, etc.). The information may be passed to other components of the device 905. The receiver 910 may be an example of aspects of the transceiver 1120 described with reference to Figure 11 The receiver 910 may utilize a single antenna or a collection of one or more antennas.

[0171] The communication manager 915 may be an example of aspects of the communication manager 815 described herein. The communication manager 915 may include an NB-IoT synchronization component 920 and a connection establishment component 925. The communication manager 915 may be an example of aspects of the communication manager 1110 described herein.

[0172] Based on implementing the synchronization techniques described herein, one or more processors of the device 905 (e.g., the processor(s) that control one or more of or are associated with the receiver 910, the communication manager 915, and the transmitter 920) may reduce the number of instances in which the device incorrectly estimates the NB-IoT carrier frequency associated with the NB cell. Additionally, the synchronization techniques may reduce latency and improve communication efficiency in the network by limiting unsuccessful synchronization attempts. Further, these techniques may allow the device to more effectively identify whether the device has incorrectly locked onto an NB cell.

[0173] The NB-IoT synchronization component 920 may identify a first synchronization procedure specific to the non-terrestrial network and different from a second synchronization procedure specific to the terrestrial network; identify a UE associated with the non-terrestrial network for synchronization with a cell associated with the base station; and synchronize with the identified UE by performing the identified synchronization procedure.

[0174] The transmitter 930 may transmit signals generated by other components of the device 905. In some examples, the transmitter 930 may be co-located with the receiver 910 in a transceiver module. For example, the transmitter 930 may be an example of aspects of the transceiver 1120 described with reference to Figure 11 The transmitter 930 may utilize a single antenna or a collection of one or more antennas.

[0175] Figure 10FIG. 1000 is a block diagram showing a communication manager 1005 that supports downlink synchronization for non-terrestrial wireless communication in accordance with aspects of the present disclosure. The communication manager 1005 may be an example of aspects of the communication manager 815, the communication manager 915, or the communication manager 1110 described herein. The communication manager 1005 may include an NB-IoT synchronization component 1010, a connection establishment component 1015, an NB-IoT channel raster component 1020, an anchor carrier transmission component 1025, an information block transmission component 1030, an ARFCN transmission component 1035, an ARFCN and cell ID mapping component 1040, and an NB-IoT synchronization signal transmitter 1045. Each of these modules may communicate directly or indirectly with each other (e.g., via one or more buses).

[0176] The NB-IoT synchronization component 1010 may identify a first synchronization procedure that is specific to a non-terrestrial network and different from a second synchronization procedure specific to a terrestrial network. In some cases, a base station may serve one or more NB-IoT-specific UEs.

[0177] In some examples, the NB-IoT synchronization component 1010 may identify a UE associated with a non-terrestrial network for synchronization with a cell associated with a base station. In some examples, the NB-IoT synchronization component 1010 may synchronize with the identified UE by performing the identified synchronization procedure.

[0178] In some examples, the connection establishment component 1015 may selectively maintain or discard a connection with a UE based on a comparison of a first carrier frequency with a true value of a carrier frequency of a cell. In some examples, the connection establishment component 1015 may maintain a connection with a UE based on the first carrier frequency matching the true value of the carrier frequency. In some examples, the connection establishment component 1015 may discard a connection with a UE based on the first carrier frequency being different from the true value of an anchor carrier frequency.

[0179] The NB-IoT channel raster component 1020 may identify a first channel raster at a frequency that is specific to a non-terrestrial network and different from a second channel raster at a frequency specific to a terrestrial network. In some cases, the first channel raster may include a cell carrier spacing that is increased in frequency relative to the second channel raster. The anchor carrier transmission component 1025 may identify a set including one or more frequency positions of at least one anchor carrier according to the first channel raster.

[0180] In some examples, the anchor carrier transmission component 1025 may transmit an anchor carrier including one or more downlink synchronization signals, wherein synchronization with a UE is based on the one or more downlink synchronization signals.

[0181] The information block transmission component 1030 may transmit an information block specific to a non-terrestrial network, where the information block includes an indication of the true value of the carrier frequency associated with a cell. The ARFCN transmission component 1035 may transmit at least a portion of the ARFCN for the cell to indicate the true value of the carrier frequency. In some cases, the information block may include the MIB. In some cases, the MIB may include a set of one or more least significant bits of the ARFCN. In some cases, the information block is an SIB that includes at least a portion of the ARFCN.

[0182] The ARFCN and cell ID mapping component 1040 may identify a valid mapping between the ARFCN and the cell ID associated with a cell, and the UE may synchronize with the cell based on the valid mapping. In some examples, the ARFCN and cell ID mapping component 1040 may determine that the mapping is a valid mapping that includes a first association between odd-numbered ARFCNs and odd-numbered cell IDs or a second association between even-numbered ARFCNs and even-numbered cell IDs, and may maintain a connection with the cell based on the valid mapping.

[0183] The NB-IoT synchronization signal transmitter 1045 may transmit one or more synchronization signals associated with a first synchronization procedure, where the one or more synchronization signals include narrowband synchronization signals.

[0184] Figure 11 A diagram of a system 1100 including a device 1105 that supports downlink synchronization for non-terrestrial wireless communication in accordance with aspects of the present disclosure is shown. The device 1105 may be an example of the device 805, the device 905, or the base station 105 described herein or include components of these devices. The device 1105 may include components for two-way voice and data communication, which include components for transmitting and receiving communication, including a communication manager 1110, a network communication manager 1115, a transceiver 1120, an antenna 1125, a memory 1130, a processor 1140, and an inter-station communication manager 1145. These components may be in electronic communication via one or more buses (e.g., bus 1150).

[0185] The communication manager 1110 may identify a first synchronization procedure specific to a non-terrestrial network and different from a second synchronization procedure specific to a terrestrial network; identify UEs associated with the non-terrestrial network for synchronizing with a cell associated with the base station; and synchronize with the identified UEs by performing the identified synchronization procedure.

[0186] The network communication manager 1115 may manage communication with the core network (e.g., via one or more wired backhaul links). For example, the network communication manager 1115 may manage the delivery of data communication of client devices (such as one or more UEs 115).

[0187] The transceiver 1120 may perform two-way communication via one or more antennas, wired or wireless links, as described herein. For example, the transceiver 1120 may represent a wireless transceiver and may perform two-way communication with another wireless transceiver. The transceiver 1120 may also include a modem to modulate packets and provide the modulated packets to the antenna for transmission, and to demodulate packets received from the antenna.

[0188] In some cases, the wireless device may include a single antenna 1125. However, in some cases, the device may have more than one antenna 1125, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

[0189] The memory 1130 may include RAM, ROM, or a combination thereof. The memory 1130 may store computer-readable code 1135 including instructions that, when executed by a processor (e.g., processor 1140), cause the device to perform the various functions described herein. In some cases, the memory 1130 may particularly include BIOS, which may control basic hardware or software operations, such as interactions with peripheral components or devices.

[0190] The processor 1140 may include intelligent hardware devices (e.g., general-purpose processors, DSPs, CPUs, microcontrollers, ASICs, FPGAs, programmable logic devices, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some cases, the processor 1140 may be configured to operate a memory array using a memory controller. In some cases, the memory controller may be integrated into the processor 1140. The processor 1140 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 1130) to cause the device 1105 to perform various functions (e.g., support functions or tasks for downlink synchronization for non-terrestrial wireless communication).

[0191] The inter-station communication manager 1145 may manage communication with other base stations 105, and may include a controller or scheduler for collaboratively controlling communication with UEs 115 with other base stations 105. For example, the inter-station communication manager 1145 may coordinate the scheduling of transmissions to UEs 115 for various interference mitigation techniques, such as beamforming or joint transmission. In some examples, the inter-station communication manager 1145 may provide an X2 interface within the LTE / LTE-A wireless communication network technology to provide communication between base stations 105.

[0192] Code 1135 may include instructions for implementing aspects of the present disclosure, including instructions for supporting wireless communication. Code 1135 may be stored in a non-transitory computer-readable medium, such as system memory or other types of memory. In some instances, code 1135 may not be directly executed by processor 1140, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0193] Figure 12 A flowchart illustrating method 1200 for supporting downlink synchronization for non-terrestrial wireless communication in accordance with aspects of the present disclosure is shown. Operations of method 1200 may be implemented by UE 115 or its components as described herein. For example, operations of method 1200 may be performed by a communication manager as described with reference to Figures 4 to 7 In some examples, the UE may execute a set of one or more instructions to control functional elements of the UE to perform the functions described herein. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the functions described herein.

[0194] At 1205, the UE may identify a first synchronization procedure that is specific to a non-terrestrial network and different from a second synchronization procedure specific to a terrestrial network. The operation at 1205 may be performed in accordance with the methods described herein. In some examples, aspects of the operation at 1205 may be performed by an NB-IoT synchronization component as described with reference to Figures 4 to 7 In some examples, aspects of the operation at 1205 may be performed by an NB-IoT synchronization component as described with reference to

[0195] At 1210, the UE may identify a cell associated with the non-terrestrial network for synchronization with the UE. The operation at 1210 may be performed in accordance with the methods described herein. In some examples, aspects of the operation at 1210 may be performed by a cell identification component as referenced Figures 4 to 7 In some examples, aspects of the operation at 1210 may be performed by a cell identification component as referenced

[0196] At 1215, the UE may synchronize with the identified cell by performing the identified synchronization procedure. The operation at 1215 may be performed in accordance with the methods described herein. In some examples, aspects of the operation at 1215 may be performed by an NB-IoT synchronization component as referenced Figures 4 to 7 In some examples, aspects of the operation at 1215 may be performed by an NB-IoT synchronization component as referenced

[0197] Figure 13 A flowchart illustrating method 1300 for supporting downlink synchronization for non-terrestrial wireless communication in accordance with aspects of the present disclosure is shown. Operations of method 1300 may be implemented by UE 115 or its components as described herein. For example, operations of method 1300 may be performed by a communication manager as described with reference to Figures 4 to 7The described communication manager performs. In some examples, the UE may execute a set of one or more instructions to control functional elements of the UE to perform the functions described herein. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the functions described herein.

[0198] At 1305, the UE may identify a first synchronization procedure that is specific to the non-terrestrial network and different from a second synchronization procedure specific to the terrestrial network. The operation of 1305 may be performed according to the methods described herein. In some examples, aspects of the operation of 1305 may be performed by an NB-IoT synchronization component as described in reference to Figures 4 to 7 as described.

[0199] At 1310, the UE may identify a cell associated with the non-terrestrial network for synchronization with the UE. The operation of 1310 may be performed according to the methods described herein. In some examples, aspects of the operation of 1310 may be performed by a cell identification component as described in reference to Figures 4 to 7 as described.

[0200] At 1315, the UE may identify a first channel raster on a frequency that is specific to the non-terrestrial network and different from a second channel raster on a frequency specific to the terrestrial network. The operation of 1315 may be performed according to the methods described herein. In some examples, aspects of the operation of 1315 may be performed by an NB-IoT channel raster component as described in reference to Figures 4 to 7 as described.

[0201] At 1320, the UE may identify a set including one or more frequency positions of at least one anchor carrier according to the first channel raster. The operation of 1320 may be performed according to the methods described herein. In some examples, aspects of the operation of 1320 may be performed by an anchor carrier monitoring component as described in reference to Figures 4 to 7 as described.

[0202] At 1325, the UE may monitor the at least one anchor carrier for one or more downlink synchronization signals, wherein synchronization with the cell is based on the one or more downlink synchronization signals. The operation of 1325 may be performed according to the methods described herein. In some examples, aspects of the operation of 1325 may be performed by an anchor carrier monitoring component as described in reference to Figures 4 to 7 as described.

[0203] At 1330, the UE may synchronize with the identified cell by executing the identified synchronization procedure. The operation of 1330 may be performed according to the methods described herein. In some examples, aspects of the operation of 1330 may be performed by an NB-IoT synchronization component as described in reference to Figures 4 to 7 as described.

[0204] Figure 14 A flowchart showing a method 1400 for supporting downlink synchronization for non-terrestrial wireless communication in accordance with aspects of the present disclosure is shown. Operations of method 1400 may be implemented by a UE 115 or components thereof as described herein. For example, operations of method 1400 may be performed by a communication manager as described with reference to Figures 4 to 7 what is described. In some examples, a UE may execute a set of one or more instructions to control functional elements of the UE to perform the functions described herein. Additionally or alternatively, a UE may use dedicated hardware to perform aspects of the functions described herein.

[0205] At 1405, the UE may identify a first synchronization procedure that is specific to a non-terrestrial network and different from a second synchronization procedure specific to a terrestrial network. The operation of 1405 may be performed in accordance with the methods described herein. In some examples, aspects of the operation of 1405 may be performed by an NB-IoT synchronization component as described with reference to Figures 4 to 7 what is described.

[0206] At 1410, the UE may identify a cell associated with the non-terrestrial network for synchronization with the UE. The operation of 1410 may be performed in accordance with the methods described herein. In some examples, aspects of the operation of 1410 may be performed by a cell identification component as described with reference to Figures 4 to 7 what is described.

[0207] At 1415, the UE may receive an information block specific to the non-terrestrial network, the information block including an indication of a true value of a carrier frequency associated with the cell. The operation of 1415 may be performed in accordance with the methods described herein. In some examples, aspects of the operation of 1415 may be performed by an information block reception component as described with reference to Figures 4 to 7 what is described.

[0208] At 1420, the UE may compare a first carrier frequency with the true value of the carrier frequency of the cell. The operation of 1420 may be performed in accordance with the methods described herein. In some examples, aspects of the operation of 1420 may be performed by a frequency comparison component as described with reference to Figures 4 to 7 what is described.

[0209] At 1425, the UE may selectively maintain or discard the connection with the cell based on the comparison. The operation of 1425 may be performed in accordance with the methods described herein. In some examples, aspects of the operation of 1425 may be performed by a connection establishment component as described with reference to Figures 4 to 7 what is described.

[0210] At 1430, the UE may synchronize with the identified cellular cell by performing the identified synchronization procedure. The operation of 1430 may be performed according to the methods described herein. In some examples, aspects of the operation of 1430 may be performed by an NB-IoT synchronization component as described with reference to Figures 4 to 7 as described.

[0211] Figure 15 FIG. 1500 is a flow diagram illustrating a method 1500 for supporting downlink synchronization for non-terrestrial wireless communication in accordance with aspects of the present disclosure. The operations of method 1500 may be implemented by a UE 115 or components thereof as described herein. For example, the operations of method 1500 may be performed by a communication manager as described with reference to Figures 4 to 7 as described. In some examples, the UE may execute a set of one or more instructions to control functional elements of the UE to perform the functions described herein. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the functions described herein.

[0212] At 1505, the UE may identify a first synchronization procedure that is specific to the non-terrestrial network and different from a second synchronization procedure specific to the terrestrial network. The operation of 1505 may be performed according to the methods described herein. In some examples, aspects of the operation of 1505 may be performed by an NB-IoT synchronization component as described with reference to Figures 4 to 7 as described.

[0213] At 1510, the UE may identify a cellular cell associated with the non-terrestrial network for synchronization with the UE. The operation of 1510 may be performed according to the methods described herein. In some examples, aspects of the operation of 1510 may be performed by a cellular cell identification component as described with reference to Figures 4 to 7 as described.

[0214] At 1515, the UE may identify a valid mapping between the ARFCN and the cellular cell ID associated with the cellular cell. The operation of 1515 may be performed according to the methods described herein. In some examples, aspects of the operation of 1515 may be performed by an ARFCN and cellular cell ID mapping component as described with reference to Figures 4 to 7 as described.

[0215] At 1520, the UE may determine to synchronize with the cellular cell based on the valid mapping (e.g., a mapping including a first association between odd-numbered ARFCNs and odd-numbered cellular cell IDs or a second association between even-numbered ARFCNs and even-numbered cellular cell IDs). The operation of 1520 may be performed according to the methods described herein. In some examples, aspects of the operation of 1520 may be performed by an undefined as described with reference to Figures 4 to 7 as described.

[0216] At 1525, the UE may synchronize with the identified cellular cell by performing the identified synchronization procedure. The operation of 1525 may be performed according to the methods described herein. In some examples, aspects of the operation of 1525 may be performed by an NB-IoT synchronization component as described with reference to Figures 4 to 7 as described.

[0217] Figure 16 FIG. 1600 is a flow diagram illustrating a method 1600 that supports downlink synchronization for non-terrestrial wireless communication in accordance with aspects of the present disclosure. The operations of method 1600 may be implemented by a base station 105 or components thereof as described herein. For example, the operations of method 1600 may be performed by a communication manager as described with reference to Figures 8 to 11 as described. In some examples, the base station may execute a set of one or more instructions to control functional elements of the base station to perform the functions described herein. Additionally or alternatively, the base station may use dedicated hardware to perform aspects of the functions described herein.

[0218] At 1605, the base station may identify a first synchronization procedure that is specific to the non-terrestrial network and different from a second synchronization procedure specific to the terrestrial network. The operation of 1605 may be performed according to the methods described herein. In some examples, aspects of the operation of 1605 may be performed by an NB-IoT synchronization component as described with reference to Figures 8 to 11 as described.

[0219] At 1610, the base station may identify a UE associated with the non-terrestrial network for synchronization with a cellular cell associated with the base station. The operation of 1610 may be performed according to the methods described herein. In some examples, aspects of the operation of 1610 may be performed by an NB-IoT synchronization component as described with reference to Figures 8 to 11 as described.

[0220] At 1615, the base station may synchronize with the identified UE by performing the identified synchronization procedure. The operation of 1615 may be performed according to the methods described herein. In some examples, aspects of the operation of 1615 may be performed by an NB-IoT synchronization component as described with reference to Figures 8 to 11 as described.

[0221] The following provides an overview of aspects of the present disclosure:

[0222] Aspect 1: A method for wireless communication at a user equipment (UE), comprising: identifying a first synchronization procedure that is specific to a non-terrestrial network and different from a second synchronization procedure specific to a terrestrial network; identifying a cellular cell associated with the non-terrestrial network for synchronization with the UE; and synchronizing with the identified cellular cell by performing the identified synchronization procedure.

[0223] Aspect 2: The method of aspect 1, wherein identifying the first synchronization procedure includes: identifying a first channel raster on a frequency specific to the non-terrestrial network and different from a second channel raster on a frequency specific to the terrestrial network; identifying, based on the first channel raster, a set of one or more frequency positions of at least one anchor carrier; and monitoring the at least one anchor carrier for one or more downlink synchronization signals, wherein synchronization with the cell is at least partially based on the one or more downlink synchronization signals.

[0224] Aspect 3: The method of aspect 2, wherein the first channel raster includes a cell carrier spacing that increases in frequency relative to the second channel raster.

[0225] Aspect 4: The method of any one of aspects 1 to 3, further comprising: receiving an information block specific to the non-terrestrial network, the information block including an indication of a true value of a carrier frequency associated with the cell.

[0226] Aspect 5: The method of aspect 4, further comprising: comparing a first carrier frequency with the true value of the carrier frequency of the cell; and selectively maintaining or discarding a connection with the cell at least partially based on the comparison.

[0227] Aspect 6: The method of aspect 5, wherein selectively maintaining or discarding a connection with the cell includes: determining that the first carrier frequency matches the true value of the carrier frequency of the cell; and maintaining a connection with the cell at least partially based on the first carrier frequency matching the true value of the carrier frequency.

[0228] Aspect 7: The method of any one of aspects 5 to 6, wherein determining whether to maintain a connection with the cell includes: determining that the first carrier frequency is different from the true value of the carrier frequency of the cell; and discarding a connection with the cell at least partially based on the first carrier frequency being different from the true value of the carrier frequency.

[0229] Aspect 8: The method of any one of aspects 4 to 7, wherein the information block including an indication of the true value of the carrier frequency further includes at least a portion of an absolute radio frequency channel number (ARFCN) for the cell.

[0230] Aspect 9: The method of aspect 8, wherein the information block is a system information block (SIB) including the at least a portion of the ARFCN.

[0231] Aspect 10: The method of any one of aspects 4 to 9, wherein the information block includes a master information block (MIB).

[0232] Aspect 11: The method of aspect 10, wherein the MIB includes a plurality of least significant bits of the ARFCN.

[0233] Aspect 12: The method as in any one of Aspects 1 to 11, further comprising: identifying a valid mapping between an absolute radio frequency channel number (ARFCN) and a cell identifier (ID) associated with the cell, wherein synchronization with the identified cell is at least partially based on the valid mapping.

[0234] Aspect 13: The method as in Aspect 12, further comprising: determining that the valid mapping includes a first association between odd-numbered ARFCNs and odd-numbered cell IDs or a second association between even-numbered ARFCNs and even-numbered cell IDs.

[0235] Aspect 14: The method as in any one of Aspects 1 to 13, further comprising: receiving one or more synchronization signals associated with a first synchronization procedure, wherein the one or more synchronization signals include narrowband synchronization signals.

[0236] Aspect 15: The method as in any one of Aspects 1 to 14, wherein the cell is a narrowband cell serving one or more user equipments (UEs) specific to narrowband (NB) Internet of Things (IoT).

[0237] Aspect 16: A method for wireless communication at a base station, comprising: identifying a first synchronization procedure specific to a non-terrestrial network and different from a second synchronization procedure specific to a terrestrial network; identifying a UE associated with the non-terrestrial network for synchronization with a cell associated with the base station; and synchronizing with the identified UE by performing the identified synchronization procedure.

[0238] Aspect 17: The method as in Aspect 16, wherein identifying the first synchronization procedure comprises: identifying a first channel raster at a frequency specific to the non-terrestrial network and different from a second channel raster at a frequency specific to the terrestrial network; identifying a set of one or more frequency positions of at least one anchor carrier according to the first channel raster; and transmitting the at least one anchor carrier including one or more downlink synchronization signals, wherein synchronization with the UE is at least partially based on the one or more downlink synchronization signals.

[0239] Aspect 18: The method as in Aspect 17, wherein the first channel raster includes a cell carrier spacing that is increased in frequency relative to the second channel raster.

[0240] Aspect 19: The method as in any one of Aspects 16 to 18, further comprising: transmitting an information block specific to the non-terrestrial network, the information block including an indication of a true value of a first carrier frequency associated with the cell.

[0241] Aspect 20: The method as in aspect 19, further comprising: comparing the first carrier frequency with the true value of the carrier frequency of the cell; and selectively maintaining or discarding the connection with the UE based at least in part on the comparison of the first carrier frequency with the true value of the carrier frequency of the cell.

[0242] Aspect 21: The method as in aspect 20, wherein selectively maintaining or discarding the connection with the cell comprises: maintaining the connection with the UE based at least in part on the first carrier frequency matching the true value of the carrier frequency.

[0243] Aspect 22: The method as in any one of aspects 20 to 21, wherein determining whether to maintain the connection with the cell comprises: discarding the connection with the UE based at least in part on the first carrier frequency being different from the true value of the carrier frequency.

[0244] Aspect 23: The method as in any one of aspects 19 to 22, further comprising: transmitting an information block further comprising at least a portion of the absolute radio frequency channel number (ARFCN) for the cell to indicate the true value of the carrier frequency.

[0245] Aspect 24: The method as in any one of aspects 19 to 23, wherein the information block comprises a master information block (MIB), and the MIB comprises a plurality of least significant bits of the ARFCN.

[0246] Aspect 25: The method as in any one of aspects 19 to 24, wherein the information block is a MIB comprising the ARFCN.

[0247] Aspect 26: The method as in any one of aspects 16 to 25, further comprising: identifying a valid mapping between the absolute radio frequency channel number (ARFCN) and the cell identifier (ID) associated with the cell, wherein synchronizing with the UE is at least in part based on the valid mapping; and determining that the valid mapping comprises a first association between odd-numbered ARFCNs and odd-numbered cell IDs or a second association between even-numbered ARFCNs and even-numbered cell IDs.

[0248] Aspect 27: The method as in any one of aspects 16 to 26, further comprising: transmitting one or more synchronization signals associated with a first synchronization procedure, wherein the one or more synchronization signals comprise narrowband synchronization signals.

[0249] Aspect 28: The method as in any one of aspects 16 to 27, wherein the base station serves one or more narrowband (NB) Internet of Things (IoT)-specific UEs.

[0250] Aspect 29: An apparatus for wireless communication at a UE, comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method of any one of Aspects 1 to 15.

[0251] Aspect 30: A device for wireless communication at a UE, comprising at least one means for performing the method of any one of Aspects 1 to 15.

[0252] Aspect 31: A non-transitory computer-readable medium storing code for wireless communication at a UE, the code comprising instructions executable by a processor to perform the method of any one of Aspects 1 to 15.

[0253] Aspect 32: An apparatus for wireless communication at a base station, comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method of any one of Aspects 16 to 28.

[0254] Aspect 33: A device for wireless communication at a base station, comprising at least one means for performing the method of any one of Aspects 16 to 28.

[0255] Aspect 34: A non-transitory computer-readable medium storing code for wireless communication at a base station, the code comprising instructions executable by a processor to perform the method of any one of Aspects 16 to 28.

[0256] It should be noted that the methods described herein describe possible implementations, and the operations and steps may be rearranged or otherwise modified and other implementations are possible. In addition, aspects from two or more methods may be combined.

[0257] Although aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described for illustrative purposes and the LTE, LTE-A, LTE-A Pro, or NR terminology may be used in most of the description, the techniques described herein may also be applied to networks other than LTE, LTE-A, LTE-A Pro, or NR networks. For example, the described techniques may be applied to various other wireless communication systems such as Ultra Mobile Broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, and other systems and radio technologies not explicitly mentioned herein.

[0258] The information and signals described herein can be represented using any of a variety of different arts and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout this description can be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0259] The various illustrative blocks and components described in connection with the disclosure herein can be implemented or performed with a general purpose processor, DSP, ASIC, CPU, FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0260] The functions described herein can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions can be stored on or transmitted via a computer-readable medium as one or more instructions or code. Other examples and implementations fall within the scope of the disclosure and the appended claims. For example, due to the nature of software, the functions described herein can be implemented using software, hardware, firmware, hardwired, or any combination thereof executed by a processor. The features implementing the functions can also be physically located in various positions, including being distributed such that portions of the functions are implemented at different physical locations.

[0261] A computer-readable medium includes both a non-transitory computer storage medium and a communication medium including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include random access memory (RAM), read only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory, compact disc ROM (CD-ROM) or other optical disc storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a general purpose or special purpose computer, or a general purpose or special purpose processor. Likewise, any connection is properly termed a computer-readable medium. For example, if software is transmitted from a web site, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. As used herein, the terms "disk" and "disc" include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc, where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations thereof are also included within the scope of computer-readable media as used herein.

[0262] As used herein, including in the claims, the term "or" as used in a list of items (e.g., a list of items prefaced by a phrase such as "at least one of" or "one or more of") indicates an inclusive listing such that, for example, a listing of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Likewise, as used herein, the phrase "based on" should not be construed as reciting a closed set of conditions including one or more conditions. For example, an example step described as "based on condition A" may be based on both condition A and condition B without departing from the scope of the disclosure. In other words, as used herein, the phrase "based on" should be construed in the same manner as the phrase "at least partially based on".

[0263] In the figures, like components or features may have the same reference numeral. Additionally, each of the same type of components may be distinguished by following the reference numeral with a dash and a second numeral that differentiates between similar components. If only the first reference numeral is used in the specification, the description may apply to any one of the similar components having the same first reference numeral regardless of the second reference numeral, or any other subsequent reference numerals.

[0264] The description set forth herein with reference to the drawings describes example configurations and does not represent all examples that may be implemented or that fall within the scope of the claims. The term "example" as used herein means "serving as an example, instance, or illustration" and does not mean "superior to" or "better than" other examples. This detailed description includes specific details to provide an understanding of the described technology. However, the technology may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0265] The description provided herein is to enable a person of ordinary skill in the art to make or use the present disclosure. Various modifications to the present disclosure will be readily apparent to those of ordinary skill in the art, and the general principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Thus, the present disclosure is not limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An apparatus for wireless communication at a user equipment (UE), comprising: Processor; Memory coupled to the processor; And Instructions stored in the memory and executable by the processor to cause the device to: Identify a first synchronization procedure specific to a non-terrestrial network and different from a second synchronization procedure specific to a terrestrial network; Identify a cell associated with the non-terrestrial network for synchronization with the UE; And Synchronize with the identified cell by executing the identified synchronization procedure.

2. The apparatus of claim 1, wherein the instructions for identifying the first synchronization procedure are executable by the processor to cause the apparatus to: Identify a first channel raster at a frequency specific to a non-terrestrial network and different from a second channel raster at a frequency specific to the terrestrial network; Identify a set of one or more frequency positions of at least one anchor carrier according to the first channel raster; and Monitor the at least one anchor carrier for one or more downlink synchronization signals, wherein synchronization with the cell is at least partially based on the one or more downlink synchronization signals.

3. The apparatus of claim 2, wherein the first channel raster includes a cell carrier spacing that increases in frequency relative to the second channel raster.

4. The apparatus of claim 1, wherein the instructions are further executable by the processor to cause the apparatus to: Receive an information block specific to a non-terrestrial network, the information block including an indication of a true value of a carrier frequency associated with the cell.

5. The apparatus of claim 4, wherein the instructions are further executable by the processor to cause the apparatus to: Compare a first carrier frequency with the true value of the carrier frequency of the cell; and Selectively maintain or discard a connection with the cell at least partially based on the comparison.

6. The apparatus of claim 5, wherein the instructions for selectively maintaining or discarding a connection with the cell are executable by the processor to cause the apparatus to: Determine that the first carrier frequency matches the true value of the carrier frequency of the cell; and Maintain a connection with the cell at least partially based on the first carrier frequency matching the true value of the carrier frequency.

7. The apparatus according to claim 5, wherein the instructions for selectively maintaining or discarding the connection to the cell are executable by the processor to cause the apparatus to: determine that the first carrier frequency is different from the true value of the carrier frequency of the cell; and at least partially based on the first carrier frequency being different from the true value of the carrier frequency, discard the connection to the cell.

8. The apparatus according to claim 4, wherein the information block including the indication of the true value of the carrier frequency further includes at least a part of the absolute radio frequency channel number (ARFCN) for the cell.

9. The apparatus according to claim 8, wherein the information block is a system information block (SIB) including at least the part of the ARFCN.

10. The apparatus according to claim 8, wherein the information block includes a master information block (MIB).

11. The apparatus according to claim 10, wherein the MIB includes a plurality of least significant bits of the ARFCN.

12. The apparatus according to claim 1, wherein the instructions are further executable by the processor to cause the apparatus to: identify a valid mapping between an absolute radio frequency channel number (ARFCN) and a cell identifier (ID) associated with the cell, wherein synchronization with the identified cell is at least partially based on the valid mapping.

13. The apparatus according to claim 12, wherein the instructions are further executable by the processor to cause the apparatus to: determine that the valid mapping includes a first association between odd-numbered ARFCNs and odd-numbered cell IDs or a second association between even-numbered ARFCNs and even-numbered cell IDs.

14. The apparatus according to claim 1, wherein the instructions are further executable by the processor to cause the apparatus to: receive one or more synchronization signals associated with the first synchronization procedure, wherein the one or more synchronization signals include narrowband synchronization signals.

15. The apparatus according to claim 1, wherein the cell is a narrowband cell serving one or more user equipments (UEs) specific to narrowband (NB) Internet of Things (IoT).

16. An apparatus for wireless communication at a network access node, comprising: Processor; Memory coupled to the processor; And Instructions stored in the memory and executable by the processor to cause the device to: Identify a first synchronization procedure specific to a non-terrestrial network and different from a second synchronization procedure specific to a terrestrial network; Identify a user equipment (UE) associated with the non-terrestrial network for synchronization with a cell associated with the network access node; And Synchronize with the identified UE by executing the identified synchronization procedure.

17. The apparatus according to claim 16, wherein the instructions for identifying the first synchronization procedure are executable by the processor to cause the apparatus to: Identify a first channel raster at a frequency specific to a non-terrestrial network and different from a second channel raster at a frequency specific to the terrestrial network; Identify a set of one or more frequency positions of at least one anchor carrier according to the first channel raster; and Transmit the at least one anchor carrier including one or more downlink synchronization signals, wherein synchronization with the UE is at least partially based on the one or more downlink synchronization signals.

18. The apparatus according to claim 17, wherein the first channel raster includes a cell carrier spacing that increases in frequency relative to the second channel raster.

19. The apparatus according to claim 16, wherein the instructions are further executable by the processor to cause the apparatus to: Transmit an information block specific to a non-terrestrial network, the information block including an indication of a true value of a carrier frequency associated with the cell.

20. The apparatus according to claim 19, wherein the instructions are further executable by the processor to cause the apparatus to: Compare a first carrier frequency with the true value of the carrier frequency of the cell; and Selectively maintain or lose a connection with the UE at least partially based on a comparison of the first carrier frequency with the true value of the carrier frequency of the cell.

21. The apparatus according to claim 20, wherein the instructions for selectively maintaining or discarding a connection with the UE are executable by the processor to cause the apparatus to: Maintain a connection with the UE at least partially based on a match between the first carrier frequency and the true value of the carrier frequency.

22. The apparatus according to claim 20, wherein the instructions for selectively maintaining or discarding a connection with the UE are executable by the processor to cause the apparatus to: Discard a connection with the UE at least partially based on the first carrier frequency being different from the true value of the carrier frequency.

23. The apparatus according to claim 19, wherein the instructions can be further executed by the processor to cause the apparatus to: Transmit the information block including at least a part of the absolute radio frequency channel number (ARFCN) for the cell to indicate the true value of the carrier frequency.

24. The apparatus according to claim 23, wherein the information block includes a master information block (MIB), and the MIB includes a plurality of least significant bits of the ARFCN.

25. The apparatus according to claim 23, wherein the information block is a system information block (SIB) including at least a part of the ARFCN.

26. The apparatus according to claim 16, wherein the instructions can be further executed by the processor to cause the apparatus to: Identify a valid mapping between an absolute radio frequency channel number (ARFCN) and a cell identifier (ID), wherein synchronization with the UE is at least partially based on the valid mapping; and Determine that the valid mapping includes a first association between odd-numbered ARFCNs and odd-numbered cell IDs or a second association between even-numbered ARFCNs and even-numbered cell IDs.

27. The apparatus according to claim 16, wherein the instructions can be further executed by the processor to cause the apparatus to: Transmit one or more synchronization signals associated with the first synchronization procedure, wherein the one or more synchronization signals include narrowband synchronization signals.

28. The apparatus according to claim 16, wherein the network access node serves one or more user equipments (UEs) specific to narrowband (NB) Internet of Things (IoT).

29. A method for wireless communication at a user equipment (UE), comprising: Identify a first synchronization procedure specific to a non-terrestrial network and different from a second synchronization procedure specific to a terrestrial network; Identify a cell associated with the non-terrestrial network for synchronization with the UE; And Synchronize with the identified cell by executing the identified synchronization procedure.

30. The method according to claim 29, further comprising: Identify a first channel raster on a frequency specific to a non-terrestrial network and different from a second channel raster on a frequency specific to the terrestrial network; Identify a set of one or more frequency positions of at least one anchor carrier according to the first channel raster; And Monitor the at least one anchor carrier for one or more downlink synchronization signals, wherein synchronization with the cell is at least partially based on the one or more downlink synchronization signals.

31. The method according to claim 30, wherein the first channel raster includes a cell carrier spacing that increases in frequency relative to the second channel raster.

32. The method according to claim 29, further comprising: Receive an information block specific to a non-terrestrial network, the information block including an indication of a true value of a carrier frequency associated with the cell.

33. The method according to claim 32, further comprising: Compare a first carrier frequency with the true value of the carrier frequency of the cell; And Selectively maintain or discard a connection with the cell at least partially based on the comparison.

34. The method according to claim 33, wherein selectively maintaining or discarding the connection to the cell comprises: Determine that the first carrier frequency matches the true value of the carrier frequency of the cell; And Maintain a connection with the cell at least partially based on the first carrier frequency matching the true value of the carrier frequency.

35. The method according to claim 33, wherein selectively maintaining or discarding the connection to the cell comprises: Determine that the first carrier frequency is different from the true value of the carrier frequency of the cell; And Discard a connection with the cell at least partially based on the first carrier frequency being different from the true value of the carrier frequency.

36. The method according to claim 32, wherein the information block comprising the indication of the true value of the carrier frequency further comprises at least a part of the absolute radio frequency channel number (ARFCN) for the cell.

37. The method according to claim 36, wherein the information block is a system information block (SIB) comprising at least a part of the ARFCN.

38. The method according to claim 36, wherein the information block comprises a master information block (MIB).

39. The method according to claim 38, wherein the MIB comprises a plurality of least significant bits of the ARFCN.

40. The method according to claim 29, further comprising: Identify a valid mapping between an absolute radio frequency channel number (ARFCN) and a cell identifier (ID) associated with the cell, wherein synchronization with the identified cell is at least partially based on the valid mapping.

41. The method according to claim 40, further comprising: Determine that the valid mapping includes a first association between an odd-numbered ARFCN and an odd-numbered cell ID or a second association between an even-numbered ARFCN and an even-numbered cell ID.

42. The method according to claim 29, further comprising: Receive one or more synchronization signals associated with the first synchronization procedure, wherein the one or more synchronization signals include narrowband synchronization signals.

43. The method according to claim 29, wherein the cell is a narrowband cell serving one or more user equipments (UEs) specific to narrowband (NB) Internet of Things (IoT).

44. A method for wireless communication at a network access node, comprising: Identify a first synchronization procedure that is specific to a non-terrestrial network and different from a second synchronization procedure specific to a terrestrial network; Identify a user equipment (UE) associated with the non-terrestrial network for synchronization with a cell associated with the network access node;And Synchronize with the identified UE by performing the identified synchronization procedure.

45. The method according to claim 44, wherein identifying the first synchronization procedure comprises: Identify a first channel raster at a frequency that is specific to the non-terrestrial network and different from a second channel raster at a frequency specific to the terrestrial network; Identify a set of one or more frequency positions of at least one anchor carrier according to the first channel raster; And Transmit the at least one anchor carrier including one or more downlink synchronization signals, wherein synchronization with the UE is at least partially based on the one or more downlink synchronization signals.

46. The method according to claim 45, wherein the first channel raster comprises a cell carrier spacing that is increased in frequency relative to the second channel raster.

47. The method according to claim 44, further comprising: Transmit an information block specific to the non-terrestrial network, the information block including an indication of a true value of a carrier frequency associated with the cell.

48. The method according to claim 47, further comprising: Compare a first carrier frequency with the true value of the carrier frequency of the cell; And Selectively maintain or lose the connection with the UE at least partially based on the comparison of the first carrier frequency with the true value of the carrier frequency of the cell.

49. The method according to claim 48, wherein selectively maintaining or discarding the connection with the UE comprises: Maintain the connection with the UE at least partially based on the first carrier frequency matching the true value of the carrier frequency.

50. The method according to claim 48, wherein selectively maintaining or discarding the connection with the UE comprises: Discard the connection with the UE at least partially based on the first carrier frequency being different from the true value of the carrier frequency.

51. The method according to claim 47, further comprising: Transmit the information block further including at least a portion of an absolute radio frequency channel number (ARFCN) for the cell to indicate the true value of the carrier frequency.

52. The method according to claim 51, wherein the information block comprises a master information block (MIB), and the MIB comprises a plurality of least significant bits of the ARFCN.

53. The method according to claim 51, wherein the information block is a system information block (SIB) comprising at least a portion of the ARFCN.

54. The method according to claim 44, further comprising: Identify a valid mapping between an absolute radio frequency channel number (ARFCN) and a cell identifier (ID), wherein synchronization with the UE is at least partially based on the valid mapping; And Determine that the valid mapping includes a first association between odd-numbered ARFCNs and odd-numbered cell IDs or a second association between even-numbered ARFCNs and even-numbered cell IDs.

55. The method according to claim 44, further comprising: Transmit one or more synchronization signals associated with the first synchronization procedure, wherein the one or more synchronization signals include narrowband synchronization signals.

56. The method according to claim 44, wherein the network access node serves one or more user equipments (UEs) specific to narrowband (NB) Internet of Things (IoT).

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