Systems and methods for controlling access in air-to-ground networks operating in unlicensed spectrum

Abstract

Techniques for controlling or managing uplink access of a UE to a base station using unlicensed spectrum include signaling an indication of different uplink access constraints such that the UE connects to the base station when the UE and / or an uplink direction between the UE and the base station satisfies the uplink access constraints. The indication can be broadcast, for example, by utilizing unused or unspecified bits in a reference or synchronization signal. The uplink access constraints can include a threshold distance of the UE from the base station, interference in the uplink direction (which can be different from interference in the downlink direction), etc. Based on the indicated constraints, the UE can determine whether to consider the base station as a candidate serving cell for wireless network access. The UE can be an in-flight aircraft, and the base station can be a logical cell of a network that provides in-flight connectivity services.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority and benefit on the filing date of U.S. Provisional Patent Application No. 63 / 006,913, entitled “Systems and methods to control access in air-to-ground networks operating in unlicensed spectrum,” filed April 8, 2020, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to using air-to-ground networks for in-flight connectivity for aircraft, and more specifically, to managing and / or controlling in-flight aircraft's access to air-to-ground networks operating in unlicensed spectrum. Background Technology

[0004] For in-flight connectivity, an aircraft in flight can connect to air-to-ground (ATG) networks operating in unlicensed spectrum, such as those operating in 2.4 GHz and / or other frequencies in the unlicensed spectrum. Typically, base stations and / or in-flight aircraft detect, transmit, and respond to interference conditions (and / or their effects), as such interference conditions have similar effects in both the radio frequency (RF) uplink (e.g., in the direction of the base station) and downlink (e.g., in the direction of the in-flight aircraft or user equipment (UE)). However, in the air span or airspace where interference affects wireless communications in the unlicensed spectrum, the uplink may experience different interference intensities than the downlink, resulting in an asymmetry in the RF path relative to the interference effect. That is, the uplink interference level in the air span or airspace may be uncorrelated or non-corresponding to the downlink interference level.

[0005] Because different types of users can access unlicensed spectrum, non-aircraft users of unlicensed spectrum (e.g., Wi-Fi or other types of unlicensed spectrum users on the ground) can be potentially strong sources of external interference in ATG in-flight connectivity networks using unlicensed spectrum. Therefore, to determine the best possible serving cell, the UE or aircraft measures the corresponding signals of all possible servers (e.g., all possible base stations or cells) and selects the one with the highest SINR (Signal-to-Interference-and-Noise Ratio) or other suitable measurements. However, while this method guarantees that the selected serving cell will provide the best signal in the downlink direction (e.g., towards the UE) among the candidate serving cells, it cannot guarantee good or even sufficient signal quality in the uplink direction (e.g., towards the cell or base station) to maintain a connection with the selected base station, given the asymmetric RF path.

[0006] The 3GPP NR specification does not provide a mechanism for signaling different direction-specific conditions to the UE and / or base station before the UE connects to the base station (e.g., when the interference level observed by the cell / base station from the direction of the UE is too high to maintain a sufficiently high quality connection). This is because the specification is intended for use in licensed spectrum where the interference levels in two directions are somewhat correlated and / or where the effects of interference can be mitigated using carrier sense multiple access / collision avoidance. For example, the 3GPP NR specification does provide indications cellBarred, cellReservedForOperatorUse, and cellReservedForOtherUse in MIB (Master Information Block) and SIB (System Information Block) messages to prevent access to certain cells that are prohibited, reserved for operator use, or reserved for certain other purposes. However, these and other similar indications defined in the 3GPP NR specification only provide a way to ensure that the transmission cell is not available at all or is only available to some users. More significantly, these and other similar indications are distinguished at the cell or base station granularity level and do not take into account spatial differences at the cell or base station. Disadvantageously, this specification does not provide a mechanism to signal the UE and instruct the mobile station to search for other candidate cells when access to a cell and / or spatial orientation should not be possible due to high reverse link interference.

[0007] Furthermore, for implementations supporting long-range air-to-ground communication, this specification does not provide a mechanism to prevent remote or distant UEs from accessing a specific cell while allowing nearby UEs to access the specific cell, for example, so that the specific cell can be optimally configured to serve a large number of UEs closer to the specific cell. Therefore, a distant UE attempting to access a cell configured to cover many near- or mid-range UEs (e.g., a high-capacity cell used to serve near- / mid-range UEs) will impair the cell's capacity. This specification does not provide a mechanism to indicate to the UE that a cell is a high-capacity cell, so that a distant UE will not attempt to access a high-capacity cell, but instead will attempt to connect to other possible candidate cells. Summary of the Invention

[0008] The embodiments of the invention described herein describe techniques, systems, and methods for managing aircraft connectivity in air-to-ground (ATG) networks operating on frequencies of 2.4 GHz and / or other unlicensed spectrum, such as during flight over air spans or in airspace containing potentially strong external interference sources. For example, the techniques, systems, and methods described herein can manage UE or aircraft access to a cell by signaling the occurrence of specific conditions in the uplink (UL) or downlink (DL) direction, wherein the conditions may differ between the uplink and downlink directions.

[0009] Generally, the techniques described herein provide a mechanism for controlling UE access to a cell or base station in the event of conditions not anticipated by the 3GPP standard. For example, the techniques may utilize reserved bits in broadcast signals (not used, defined, or specified within the 3GPP NR standard) to transmit information to the UE indicating various conditions or constraints that may affect the UE's corresponding uplink access to the cell. Additionally or alternatively, these techniques may restrict access to some UEs with conflicting radio requirements, for example, due to the relative distance between the UE and the cell site, compared to most UEs that can access the cell site. Still additionally or alternatively, the techniques may signal to the UE detected external interference, and in some embodiments, may indicate corresponding levels of external interference in different directions in airspace (e.g., different levels of uplink and / or downlink interference).

[0010] In embodiments, the technology utilized by embodiments of the invention defines the use of broadcast bits, which are not used in the 3GPPNR specification (e.g., reserved or unspecified), to signal to the UE specific directional channel or network conditions or constraints, thereby controlling the UE's (e.g., an aircraft's) access to the cell. By signaling to the UE specific conditions or access constraints, such as high UL (uplink) external interference, different UE behaviors can be implemented in response to the signaled conditions. For example, the UE may search for different cells or servers, or the UE may wait a predefined time before retrying access to the cell. Similarly, by signaling to the UE that the cell is intended to serve a certain type of many connections (e.g., the cell is configured to optimally serve a certain type of high-capacity cell) and / or is configured to optimally serve UEs within a specific distance of the cell, UEs located far from the cell may search for different cells or servers. Additionally, if a narrow beam is used to broadcast the indicated access conditions or constraints, the indication signaled by the cell can be specific to the conditions or constraints in the spatial direction of the beam, and thus can indicate different uplink access conditions or constraints for different beams of a single cell site.

[0011] In one embodiment, a method for managing a user equipment (UE)'s access to a wireless network via unlicensed spectrum includes receiving, at the UE, a signal generated by a first cell of the wireless network via the unlicensed spectrum. The signal includes an indication of the presence or absence of one or more uplink access constraints of the first cell, wherein the one or more uplink access constraints include at least one of the following: a threshold distance between the UE and the first cell, or uplink interference detected by the first cell in the spatial direction of the UE. The method further includes the UE selecting a serving cell of the wireless network based on the indicated one or more uplink access constraints, and the UE connecting to the selected serving cell.

[0012] In one embodiment, a method for managing a user equipment (UE)'s access to a wireless network via unlicensed spectrum includes a reference signal transmitted by a cell of the wireless network within the unlicensed spectrum. The reference signal has a first portion used by the UE to determine downlink interference; and a second portion comprising a set of reserved bits having a specific purpose not designated for the reference signal, wherein the reserved bits have values ​​indicating the presence or absence of a corresponding uplink access constraint specific to the cell. The UE determines whether to communicatively connect to the cell based on the reference signal. Attached Figure Description

[0013] Figure 1Examples of embodiments of methods, systems, and techniques for managing user equipment (UE) access to a wireless network via unlicensed spectrum are described.

[0014] Figure 2 This describes examples of downlink transmissions that can be described in embodiments of methods, systems, and techniques for managing user equipment (UE) access to wireless networks via unlicensed spectrum disclosed herein.

[0015] Figure 3 The illustration depicts an embodiment of a method, system, and technique for managing user equipment (UE) access to a wireless network via unlicensed spectrum.

[0016] Figure 4 A flowchart depicts an example method for managing user equipment (UE) access to a wireless network via unlicensed spectrum.

[0017] Figure 5 A flowchart depicts an example method for managing user equipment (UE) access to a wireless network via unlicensed spectrum.

[0018] Figure 6 This is a block diagram of an instance computing system that can be used in conjunction with embodiments of the techniques described herein. Detailed Implementation

[0019] Although specific embodiments of the methods, apparatus, and / or articles of manufacture are disclosed below, it should be understood that the legal scope of the property is defined by the wording of the claims set forth at the end of this patent. Therefore, the specific embodiments described below should be interpreted as merely examples and not as a description of every possible instance, as describing every possible instance would be impractical, if not impossible. Many alternative embodiments can be implemented using current technology or technology developed after the filing date of this patent. It is anticipated that such alternative embodiments will still fall within the scope of the claims.

[0020] Figure 1 Example scenario 100 depicts an embodiment of a method, system, and technique for managing a user equipment (UE)’s access to a wireless network via unlicensed spectrum. Figure 1Scenario 100 depicts two base stations or cell sites 102, 105 of a wireless network, wherein cell sites 102, 105 transmit and receive radio signals in unlicensed spectrum. For example, at least one of base stations 102, 105 may be a gNB (Next Generation Node B) of a 5G wireless network utilizing NR (New Radio) technology in unlicensed spectrum, and / or at least one of base stations 102, 105 may be another type of logical radio node of another generation of wireless network (e.g., a 6G wireless network) utilizing the corresponding radio technology in unlicensed spectrum. Each base station 102, 105 contains six sectors (represented by labels 0, 1, 2, 3, 4, 5). In its sector 0, cell site 102 broadcasts four different reference signals 108a-108d in different spatial directions (e.g., different three-dimensional directions) for UE to receive and process, so that the UE can determine the appropriate cell site to which it can connect to the wireless network for in-flight connectivity. As used herein, the term "spatial orientation" generally refers to an angular range (e.g., a three-dimensional angular range) corresponding to the beamwidth of a directional beam, such as the directional beams through which reference signals 108a-108d are transmitted, respectively. Additionally, in scenario 100, two user equipments (UEs) 110, 112 (described as two aircraft 110, 112 in scenario 100) are located within the serving air span or airspace of cell site 102. Each UE 110, 112 radiates corresponding beams 115, 118 to detect reference signals, such as reference signals 108a-108d, for candidate serving cell sites.

[0021] like Figure 1 The diagram further depicts that, within the line-of-sight or point-to-point direction (indicated by dashed line 120) between UE 112 and cell site 102, there is no external interference or negligible external interference. On the other hand, within the line-of-sight or point-to-point direction (indicated by dashed line 122) between UE 110 and cell site 102, the terrestrial or ground base station 125 serving the terrestrial mobile device radiates energy within the same unlicensed spectrum used by cell site 102 (e.g., thereby allowing terrestrial base station 125 to provide wireless connectivity to the terrestrial mobile device via unlicensed spectrum). Therefore, in scenario 100, terrestrial base station 125 is an external interference source relative to UE 110 and cell site 102. Cell site 102 detects and measures the interference generated by terrestrial base station 125 in the line-of-sight direction 122 of UE 110 (as indicated by arrow 128). That is, cell site 102 detects and measures external interference in the uplink (UL) direction 128 of the line-of-sight direction 122 of UE 110.

[0022] After detecting and determining that the level of uplink interference 128 is greater than an interference threshold, cell site 102 notifies UE 110 (and any other UE capable of receiving reference signal 108c radiated in the spatial direction corresponding to UE 110) of the detected non-negligible uplink interference via reference signal 108c. Therefore, at least due to the detection of a significant level of external uplink interference 128 between cell site 102 and UE 110 in the line-of-sight direction 122, UE 110 is notified that it may need to consider other candidate cells (e.g., by processing reference signals broadcast by other candidate cells) to discover a suitable cell through which UE 110 can connect to the wireless network. In practice, as... Figure 1 As shown, in response to receiving a notification of uplink interference 128 detected in the direction of cell site 102, UE 110 directs its antenna radiation pattern 115 to search for other suitable cells, such as cell site 105, via which it accesses the wireless network.

[0023] On the other hand, cell site 102 does not detect any uplink interference in the uplink direction of the line-of-sight direction 118 between cell site 102 and UE 112. For example, cell site 102 detects negligible uplink interference or uplink interference levels below an interference threshold in the uplink line-of-sight direction 118 between cell site 102 and UE 112. Therefore, cell site 102 notifies UE 112 (and any other UE capable of receiving reference signal 108a radiated in the spatial direction corresponding to UE 112) via reference signal 108a that cell 102 has not detected uplink interference or has detected negligible uplink interference in the corresponding spatial direction. Therefore, UE 112 can select cell 102 as the serving cell, for example, assuming that UE 112 also determines, based on reference signal 108a, that downlink (DL) interference in the downlink direction of the line-of-sight direction 118 is negligible or acceptable and meets other access conditions / constraints.

[0024] It should be noted that in scenario 100, base station 102 radiates reference signals 108a-108n of sector 0 (and other reference signals of other sectors) in a directional manner, for example, in different spatial directions, which may correspond to different spatial directions of the narrow beam radiated by the base station. Therefore, the interference from external sources may differ for different spatial directions (e.g., spatial direction 108c has interference from source 125 at a level higher than the interference threshold, while spatial direction 108a does not have interference from source 125 at a level higher than the interference threshold). Furthermore, at least due to the different spatial directions of the different beams, some external signals may more strongly interfere with transmission in a specific uplink spatial direction between the UE and the cell compared to the corresponding downlink spatial direction. For example, in spatial direction 108c corresponding to the line-of-sight 122 between UE 110 and base station 102, the uplink interference 128 level caused by source 125 is greater than the downlink interference level caused by source 125. Therefore, although UE110 may determine, by measurement or other means (e.g., based on reference signal 108c), that the downlink interference between UE110 and cell 102 is at an acceptable level, UE110 may not select cell 102 as the serving cell when reference signal 108c indicates the presence of significant uplink interference 128.

[0025] In an embodiment, each reference signal (e.g., signals 108a, 108b, 108c, 108d) broadcast by cell site 102 can be a synchronization signal. The UE can process the synchronization signals to determine candidate serving cells and / or connect to the selected serving cell. For example, the 3GPP NR specification defines synchronization signals broadcast by base stations, such as the primary synchronization channel (PSS), secondary synchronization channel (SSS), and physical broadcast channel (PBCH), which are generally referred to collectively as synchronization signal / PBCH block or SSB. The UE can process the SSB (e.g., the SSB can be decoded) to determine the identifier of the broadcast cell, synchronize with the broadcast cell, and / or determine the downlink power and / or downlink interference relative to the broadcast cell in order to select the most suitable serving cell from a set of candidate serving cells. For example, the UE can determine the downlink interference corresponding to the broadcast cell by determining the SINR of the SSB broadcast by the cell or other suitable measurements.

[0026] Figure 2 This section describes the bit layout of a portion of the SSB 200. The SSB 200 section depicts the last eight bits of the PBCH payload. The 3GPP NR specification defines or specifies it as the transmission of various physical layer information. For spectrum below 6 GHz, the maximum number of SSB beams is eight or four, therefore the last two bits of the SSB, for example, are... and These are bits that are not used and are defined by the specification as reserved, unused, or unspecified. Embodiments of the invention described herein can utilize these unspecified bits to signal to the UE an indication of the presence or absence of one or more uplink access constraints or conditions, thereby controlling the UE's access to the cell. For example, in an example implementation:

[0027] (i) position This can be used to indicate the presence or absence of UL interference above an interference threshold, such as through observation or determination via broadcast cells. For example, a bit value of 0 can indicate acceptable UL interference, and a bit value of 1 can indicate higher or unacceptable UL interference.

[0028] (ii) bit This can be used to indicate the presence or absence of a UE and a threshold distance from the broadcast cell, wherein the broadcast cell is optimally configured to serve UEs located within the threshold distance of the cell. For example, a bit value of 0 can indicate that the cell serves all UEs regardless of the distance between the UE and the cell, and a bit value of 1 can indicate that the cell is specifically configured to optimally and preferably serve UEs located within the threshold distance.

[0029] In other words, the cell can utilize the SSB 200's bit depth. This indicates the presence or absence of uplink access constraints corresponding to UL interference, and the cell can utilize bits... This indicates whether or not an access constraint corresponding to the threshold distance between the UE and the cell exists. Additional details regarding the use of the threshold distance between the UE and the cell site are discussed in more detail elsewhere in this disclosure.

[0030] Advantageously, and as Figure 2 As shown, SSB block 200 has spatial characteristics, such as being indicated by a vector or spatial symbol. Therefore, in this example embodiment, bits... The corresponding values ​​can vary for the corresponding SSBs transmitted by the cell in different spatial directions, thus reflecting the corresponding channel conditions and / or other uplink access constraints (e.g., based on each beam) in the different spatial directions relative to the cell. For example, in the case of UL interference, external interference sources on the ground may cause higher interference levels only in specific directions, and therefore The value may differ across different SSB beams. For example, to illustrate the reference... Figure 1 The SSB transmitted in the spatial direction 108c can have a corresponding bit set to "1". The value indicates that an unacceptable level of UL interference was detected by cell 102 in spatial direction 108c (e.g., due to external interference source 125), and SSBs transmitted in spatial directions 108a, 108b, and 108d respectively may have bits set to "0". The value indicates that cell 102 has not detected or has detected an acceptable level of UL interference in the corresponding spatial directions 108a, 108b, 108d.

[0031] Therefore, in this embodiment, when cell 102 sends the bit of SSB 200 The value is set to "1" (for example, an SSB transmitted in spatial direction 108c, such as...). Figure 1 When (as shown in the diagram), cell 102 thereby notifies UE 110 of the corresponding sector (e.g., sector 0 of cell 102, such as...). Figure 1 As shown, the UE110 is under high UL interference in direction 122 corresponding to SSB beam 108c, and therefore, UE110 should search for other candidate cells for connecting to the wireless network. For example, as Figure 1 As described, land-based interference source 125 has a direct line of sight to cell 102 and provides strong interference to the SSB area represented by 108c. UE110 is within the coverage area of ​​the SSB area represented by 108c and therefore receives signals with bits set to "1". The broadcast SSB. Therefore, UE 110 continues to search for other candidate serving cells, such as sector 5 of cell 105, as indicated by the spatial direction of beam 115 generated by UE 110. However, UE 112 is within the coverage area of ​​the SSB area indicated by 108a, and therefore receives the signal with the bit set to "0". The SSB, and therefore continues to attempt to access sector 0 of cell 102, as indicated by the spatial direction of beam 118 generated by UE112.

[0032] Alternatively or concurrently, in this example implementation, by using the bits of SSB 200 When the value is set to "1", the cell can instruct the UE that it should search for other candidate cells to connect to, relative to the cell at a spatial distance greater than a predefined threshold (e.g., 250 km, or some other distance that would require time division duplex (TDD) based on physical layer structure splitting). In other words, the cell can restrict or constrain the UE's uplink access to the cell based on the corresponding spatial distance between the UE and the cell.

[0033] To illustrate, Figure 3 Describe instance 300 in which this situation occurs. Figure 3In this context, cell 302 is specifically configured to serve a large number of UEs 310 within a relatively close range. That is, cell 302 is optimally configured as a high-capacity cell to serve a large number of short- or medium-range UEs 310, for example, when cell 302 is configured to provide coverage for in-flight connectivity at or near an airport in a high-altitude air traffic corridor. For example, cell 302 can be configured to utilize a TDD frame configuration optimized for UEs 310 located within a predefined threshold distance from cell 302. Therefore, cell 302 restricts UE access based on its corresponding distance from cell 302, for example, to avoid the need to reconfigure the TDD frame configuration, and / or to achieve high-capacity service that cell 302 will provide at the appropriate location or environment within the wireless network.

[0034] In scenario 300, a remote or distant UE 312 can receive broadcast transmissions (e.g., SSBs) from cell 302 with sufficient SINR (e.g., based on a SINR threshold) for connection purposes. However, since cell 302 has been specifically configured as a high-capacity cell to serve low- or medium-range UE 310, cell 302 will broadcast bits in the SSB. The value is set to "1". Based on the SSB bit... The value is set to "1" and based on the fact that the spatial distance between UE 312 and cell 302 is greater than the threshold distance, even if the SINR is sufficient, UE 312 will not attempt to access cell 302, and will instead search for other candidate serving cells, such as cell 305, as indicated by the spatial direction of beam 315 generated by UE 312. Figure 3 The Chinese side indicated that...

[0035] therefore, Figure 3 The techniques described herein can prevent or avoid the use of TDD frame configurations that cannot meet the data needs of UE 312 located at a remote location, without significantly impairing the needs of other UEs 310 located closer to the site. Alternatively or concurrently, Figure 3 The techniques described herein can prevent or avoid reconfiguring the entire cell 302 using TDD frame configurations that may be suitable for UE 312 located at a distance, but would also waste cell 302 capacity and affect the throughput of other UEs 310 located closer to the cell and served by cell 302. Therefore, in embodiments where cell 302 is a high-capacity cell configured to serve near- or mid-range UEs, the radio configuration can be consistent or identical throughout cell 302, and thus... The value of the bit will be set to "1" in all SSBs broadcast by cell 302.

[0036] Figure 4A flowchart depicts an example method 400 for managing a user equipment (UE)'s access to a wireless network via unlicensed spectrum, based on at least some of the principles and techniques disclosed herein. Method 400 can be combined with... Figure 1 and 3 The scenarios and / or environments described herein, and / or other environments in which the UE attempts to access a wireless network via a cell or a base station via unlicensed spectrum. In embodiments, the UE (e.g., UE 110, UE 112, or UE 312) may perform at least a portion of method 400. For example, one or more processors of the UE may execute instructions stored in one or more physical memories of the UE to perform at least a portion of method 400. In embodiments, method 400 may include additional or alternative steps.

[0037] At block 402, method 400 may include receiving, at the UE, a signal generated and transmitted by a first cell of a wireless network via unlicensed spectrum. For example, the signal may be a reference signal, a synchronization signal, or another type of signal broadcast by the first cell. The signal may contain an indication of the corresponding presence or absence of one or more uplink access constraints of the first cell. One or more constraints for uplink access to the first cell may include a threshold distance (e.g., threshold spatial distance) between the UE and the first cell, uplink interference detected by the first cell in the uplink spatial direction corresponding to the UE, and / or other types of conditions or constraints on the airspace between the UE and / or the first cell for uplink access to the first cell. In embodiments, the corresponding presence or absence of one or more uplink access constraints may be indicated by bit values ​​contained in the signal transmitted by the first cell. For example, the corresponding presence or absence of various uplink access conditions may be indicated, for example, relative to... Figure 2 The manner of description is indicated in a set of reserved or unspecified bit values ​​of the SSB broadcast by the first cell.

[0038] At block 405, method 400 may additionally include the UE selecting a serving cell for the wireless network based on indications of the presence or absence of corresponding uplink access constraints of one or more uplink access constraints of the first cell. Generally, when the UE and / or when all uplink access constraints indicating presence in the first cell are satisfied in the uplink direction between the UE and the first cell, the UE may continue to evaluate received signals (e.g., received SSBs) for further suitability as a serving cell. For example, the UE may determine the downlink interference level between the UE and the first cell based on other information contained in the received signals. When the downlink interference level is determined or measured to be acceptable, the UE may include a first cell from a set of candidate cells, from which the UE selects the serving cell 405. In practice, if the first cell is the most suitable cell in the set of candidate cells, the UE may select the first cell 405 as the serving cell.

[0039] On the other hand, when the UE and / or does not satisfy all uplink access constraints indicated as present in the uplink direction between the UE and the first cell, the UE can exclude the first cell from a set of candidate cells and select a suitable serving cell from the set of candidate cells. That is, when the UE and / or does not satisfy all uplink access constraints indicated as present by the first cell in the uplink direction between the UE and the first cell, the UE can avoid selecting the first cell as the serving cell. Alternatively, when the UE and / or does not satisfy all uplink access constraints indicated as present in the uplink direction between the UE and the first cell, the UE can wait for a predetermined amount of time and then evaluate another reference signal transmitted by the first cell (e.g., a second received SSB), which may contain an updated set of indications corresponding to the presence or absence of one or more uplink access constraints. The UE can include or exclude the first cell from the set of candidate serving cells based on the updated indications.

[0040] In some cases, the received signal may indicate the presence of uplink access constraints at a first cell corresponding to a threshold distance, thereby indicating that the first cell is configured as a high-capacity cell and / or configured to optimally serve UEs located within the threshold distance. When the UE is located at a spatial distance less than or equal to that of the first cell, the UE may satisfy the threshold distance constraint; when the UE is located at a spatial distance greater than the threshold distance of the first cell, the UE may not satisfy the threshold distance constraint. In embodiments, the threshold distance may be predefined and stored in the UE's memory.

[0041] In some cases, the received signal may indicate the presence of an unwanted uplink interference level detected by the first cell in the spatial direction corresponding to the UE. That is, the received signal may indicate an uplink interference level greater than an interference threshold detected by the first cell in the spatial direction corresponding to the UE. For example, the uplink interference level between the UE and the first cell in the spatial direction may differ from the downlink interference level between the UE and the first cell in the spatial direction. In these cases, the UE may exclude the first cell from the set of candidate cells, select the 405 serving cell from the set of candidate cells, or the UE may wait for a predetermined time, after which the UE processes another received signal that potentially contains an updated indication of the presence or absence of the unwanted uplink interference level, and responds accordingly.

[0042] At box 408, method 400 may include, for example, after selecting a serving cell, the UE connecting to the selected serving cell.

[0043] Figure 5 A flowchart depicts an example method 500 for managing a user equipment (UE)'s access to a wireless network via unlicensed spectrum, based on at least some of the principles and techniques disclosed herein. Method 500 can be combined with... Figure 1 and 3 The scenarios and / or environments described herein, and / or other environments in which the UE attempts to access a wireless network via a cell or via unlicensed spectrum from a base station. In embodiments, a base station or cell site (e.g., base stations 102, 105, 302, 305) may perform at least a portion of method 500. For example, one or more processors of the base station may execute instructions stored in one or more physical memories of the UE to perform at least a portion of method 500. In embodiments, method 500 may be performed in conjunction with method 300, for example, over a wireless network span or in airspace. In embodiments, method 500 may include additional or alternative steps.

[0044] At block 502, method 500 may include the transmission of a reference signal by a cell of a wireless network in unlicensed spectrum. For example, the reference signal may be a synchronization signal or another type of signal broadcast by the cell. The reference signal may include an indication of the corresponding presence or absence of one or more uplink access constraints of the cell, wherein one or more constraints for uplink access to the cell via the uplink include a threshold distance (e.g., threshold spatial distance) between the UE and a first cell, uplink interference detected by the first cell (e.g., in the uplink spatial direction corresponding to the UE), and / or other types of conditions or constraints on the airspace between the UE and the cell for uplink access to the cell. In embodiments, the reference signal may have a first portion, which may be used by the UE to determine downlink interference; and a second portion, which includes a set of reserved bits with no specified use for a corresponding purpose of the reference signal. For example, relative to... Figure 2 In this manner, the set of reserved bits may have values ​​indicating the presence or absence of a corresponding uplink access condition or constraint specific to the cell. Generally, for example, as described elsewhere in this disclosure, a UE may consider a cell as a candidate cell when the UE and / or in the uplink direction in the air space between the UE and the cell satisfies all indicated uplink access constraints, and a UE may avoid or delay considering a cell as a candidate cell when the UE and / or in the uplink direction in the air space between the UE and the cell does not satisfy at least one indicated uplink access constraint.

[0045] Since one of the uplink access constraints may correspond to uplink interference in the spatial direction between the UE and the cell (the level of which may differ from any downlink interference in the same spatial direction), in some embodiments (not shown), method 500 includes detecting or determining the level of uplink interference in the unlicensed spectrum by the cell and determining whether the uplink interference level exceeds an interference threshold. For example, the determination of the uplink interference level may be made without considering or independently of any downlink interference level. Method 500 may further include, for example, indicating the presence or absence of detected or determined excessive uplink interference in the reference signal by correspondingly setting or not setting the values ​​of the set of reserved bits of the reference signal. In some embodiments (not shown), method 500 includes determining the corresponding uplink interference level in the unlicensed spectrum for each of a plurality of spatial directions corresponding to a plurality of beams radiated by the cell. In these embodiments, method 500 may include determining whether each corresponding uplink interference level exceeds an interference threshold, and indicating the presence or absence of excessive uplink interference in each spatial direction in the corresponding reference signal radiated in the corresponding spatial direction, for example by setting or not setting the value of the set of reserved bits in the corresponding reference signal accordingly.

[0046] In some cases, such as when the cell is configured to utilize a time-division duplex (TDD) frame configuration optimized for UEs located within a threshold distance from the cell (e.g., 250 km or some other suitable threshold distance), and / or when the cell is configured as a high-capacity cell within a wireless network, the Transmit 502 Reference Signal may include at least one reserved bit of the Transmit Reference Signal, the at least one reserved bit having a value indicating the presence of an uplink access constraint corresponding to the threshold distance from the cell. In these cases, when the spatial distance between the UE and the cell is less than or equal to the threshold distance, the UE communicatively connects to the cell, and when the spatial distance between the UE and the cell exceeds the threshold distance, the UE avoids or delays considering the cell as a candidate serving cell.

[0047] At optional box 505, method 500 may include connecting to the UE based on a reference signal. For example, a base station may connect to the UE, which determines, at least in part, that the base station is the most suitable candidate cell in a set of candidate cells based on a reference signal transmitted by the base station. After communicatively connecting to the UE, the base station may be the serving cell of the UE, thereby communicatively connecting the UE to the wireless network.

[0048] Turn now Figure 6 , Figure 6This is a block diagram of an example computing system 600 that can be used in conjunction with embodiments of the systems, methods, and techniques described herein. System 600 includes one or more computing devices 602, which may be specifically configured to automatically control one or more components of a wireless communication network and system operating in unlicensed spectrum, such as base stations, cell sites, gNBs, aircraft, UEs, and corresponding portions or sub-components thereof. For example, different instances of at least a portion of computing system 600 may be located at base stations, cell sites, gNBs, and / or other types of ground stations; and / or in aircraft or other types of UEs. Thus, computing device 602 may be communicatively connected to one or more sub-components of the resident components of the wireless communication system, such as transceivers, transmitters, receivers, modulators, demodulators, baseband units, remote radio units, radios, antennas, etc., and may control at least a portion of the behavior of said sub-components.

[0049] like Figure 6 As described herein, one or more computing devices 602 associated with wireless communication networks using unlicensed spectrum may include, for example, one or more processors and / or controllers, computers, portable computing devices (e.g., tablet computers, laptop computers, mobile devices, etc.), servers, multiple networked or packet computing devices or servers having the logical appearance of a single computing device or server, multiple cloud computing devices, etc. Therefore, for the purposes of discussion and not limitation, the singular tense is used herein to refer to a group of computing devices 602, although in some embodiments, computing device 602 may include more than one physical computing device.

[0050] The computing device 602 may include, for example, one or more processors 605 (e.g., a central processing unit or CPU, a digital signal processor or DSP, a microprocessor, etc.), one or more controllers 608 (e.g., a radio resource controller), one or more sets of computer-readable and / or computer-executable instructions, such as instructions 612a-612c, one or more program memories 610, random access memory (RAM) 615, and input / output (I / O) circuitry 618, all of which may be interconnected via an address / data bus 620. The one or more program memories 610 may include one or more tangible, non-transitory computer-readable storage media and / or means, and the computer-readable and / or computer-executable instructions 612a-612c stored thereon, when executed by the processor 605, may cause the computing device 602 to perform one or more and / or portions of the methods 400, 500 disclosed herein. For example, at least some of the computer-executable instructions 612 are executable to set bit values ​​in a reference signal, perform decoding and / or decoding of the reference signal, perform at least a portion of method 400, perform at least a portion of method 500, control one or more components of an air-to-ground system, and / or execute one or more other applications associated therewith.

[0051] In doing so, computing device 602 may access one or more data or memory storage devices 622a, 622b, where data corresponding to system 600 may be stored. One or more data storage devices 622 may include, for example, one or more memories, one or more memory devices, a database, a cloud data storage device, and / or one or more other suitable data storage devices. At least one of the data or memory storage devices 622a may be included in computing device 602, and processor 605 of computing device 602 (or instructions 612a-612c executed by processor 605) may access one or more data storage devices 622 via links and / or via bus 620, including read or write commands, functions, application programming interfaces, plug-ins, operations, instructions, and / or the like (which in turn may be provided by computing device 602 in this embodiment).

[0052] In an embodiment, computing device 602 may access remotely located data storage device 622b via one or more network or communication interfaces 625, which are respectively coupled to links 628 that are communicatively connected to one or more remote data storage devices 622b. Figure 6Link 628 is depicted as a link to one or more private and / or public networks 630; however, computing device 602 and remotely located data storage device 622b do not require a communicative connection to network 630. For example, link 628 may provide a direct connection between computing device 602 and data storage device 622b. Link 628 may include wired links and / or one or more wireless links, and / or may utilize any suitable communication technology. Network 630 may include one or more private networks, the public Internet, one or more virtual private networks, and / or other types of networks, such as dedicated access lines, ordinary telephone lines, satellite links, data networks, combinations thereof, etc.

[0053] In an embodiment, system 600 may include a user interface 632 through which an operator can set and / or change thresholds and / or other parameters, such as interference thresholds and / or distance thresholds.

[0054] It should be noted that, although in Figure 6 In this embodiment, the computing device 602, data storage devices 622a, and 622b of system 600 are described as separate and distinct entities; however, this is only one of many embodiments. For example, any number of any devices 602 and / or data storage devices 622 may be included in network 630. Alternatively or additionally, any number of any devices 602 may be logical, combined, or integrated devices or sets of devices.

[0055] Furthermore, although instruction 612 is in contrast to computing device 602... Figure 6 The instructions 610 are shown as three different blocks 612a, 612b, and 612c. However, it should be understood that the instructions 610 can contain any number of different programs, modules, routines, and / or subroutines that can collectively enable the computing device 602 to perform their respective functions. Furthermore, it should be understood that although only one processor 605 is shown, the computing device 602 can contain multiple processors 605, such as one or more central processing units (CPUs) and / or one or more digital signal processors (DSPs). Additionally, although the I / O circuitry 618 is shown as a single block, it should be understood that the I / O circuitry 618 can contain multiple I / O circuits of different types. Similarly, the memories 610 and 615 of the computing device 602 can contain multiple RAMs 615 and / or multiple program memories 610. Moreover, although the instructions 612 are shown as stored in the program memory 610, any or all of the instructions 612 can additionally or alternatively be partially or wholly stored in RAM 615 and / or other suitable local memory (not shown).

[0056] RAM 615 and / or program memory 610 may be implemented as semiconductor memory, magnetically readable memory, chemically or biologically readable memory, and / or optically readable memory, and / or may utilize one or more of any suitable memory technologies. In some embodiments, computing device 602 may also be operatively connected to network 630 via link 628 and I / O circuitry 618.

[0057] The embodiments of the techniques described herein offer significant advantages and benefits over known techniques. As previously discussed, the 3GPP standard specification does not provide a mechanism for base stations to notify UEs of high interference levels in the uplink direction because the 3GPP standard is specifically designed for licensed spectrum where there is no explicit indication of external interference and / or where carrier sense multiple access and collision avoidance can be employed. However, in unlicensed spectrum, as different types of users, base stations, and communication systems other than ATG users, base stations, and communication systems can utilize such unlicensed spectrum at any time, these other types of users, base stations, and / or systems can be external sources of interference for ATG wireless networks at any time, and disadvantageously, the 3GPP standard does not provide a mechanism for base stations to notify UEs of detected high UL interference levels for uplink access purposes. Furthermore, although potential external interference sources may generate directional interference (e.g., UL and DL), the UE cannot confirm or otherwise determine the difference between UL and DL interference levels. Furthermore, known technologies cannot signal uplink access conditions or constraints on a per-spatial-direction basis, and they cannot prevent or block uplink access for UEs that may require different TDD configurations (e.g., remotely located UEs), and thus can significantly reduce sector or cell capacity and / or performance, or may even reduce the performance of the entire sector or cell.

[0058] Fortunately, as discussed above, the novel and non-obvious techniques disclosed herein address these and other drawbacks. For example, the techniques described herein avoid spectral band changes to unlicensed spectrum below 6 GHz by 3GPP standards, thus minimizing the impact on UE and base station software modifications. For example, embodiments of the techniques described herein utilize bits of available but unused capacity in some frequency configurations and therefore additionally wasted. Furthermore, the techniques described herein allow the UE to be notified of changes in channel conditions with spatial dimensions before attempting cell access. Importantly, the novel techniques described herein help mitigate unintended external UL interference in ATG wireless networks and / or control UL access to cells for remotely located UEs, particularly those configured to serve a large number of short- to mid-range UEs within the ATG network, thereby increasing the efficiency of such cells.

[0059] Therefore, as described above, the novel technology described in this paper can maintain high access reliability standards for uplink and downlink connections between aircraft and serving base station cells, and helps to manage high-capacity cells in an efficient manner.

[0060] Furthermore, while the systems, methods, and techniques described herein can be applied to UEs as aircraft in flight and to wireless networks as air-to-ground communication networks operating on unlicensed spectrum, those skilled in the art will recognize that the described systems, methods, and techniques can be readily applied to UEs as personal electronic devices (e.g., laptops, smart devices, tablets, etc.), as well as UEs as vessels, automobiles, buses, or other types of vehicles. Additionally, those skilled in the art will recognize that the systems, methods, and techniques described herein can be readily applied to wireless networks that provide land-based or ground-based wireless connectivity and / or wireless connectivity for vehicles and devices operating on oceans, lakes, and other bodies of water.

[0061] Additional considerations

[0062] Throughout this specification, multiple instances can implement components, operations, or structures described as a single instance. Although individual operations of one or more methods are shown and described as separate operations, one or more of these individual operations can be performed simultaneously, and they do not need to be performed in the order shown. Structures and functions presented as independent components in an instance configuration can be implemented as composite structures or components. Similarly, structures and functions presented as single components can be implemented as separate components. These and other variations, modifications, additions, and improvements fall within the scope of this document.

[0063] Additionally, some embodiments are described herein as including logic or a number of routines, subroutines, application programs, or instructions. These can constitute software (e.g., code embodied on a non-transitory machine-readable medium) or hardware. In hardware, routines, etc., are tangible units capable of performing certain operations and can be configured or arranged in a certain way. In exemplary embodiments, one or more computer systems (e.g., standalone client or server computer systems) or one or more hardware modules of a computer system (e.g., processors or processor groups) can be configured by software (e.g., applications or application portions) to operate as hardware modules to perform certain operations as described herein.

[0064] In various embodiments, the hardware module may be implemented mechanically or electronically. For example, the hardware module may include dedicated circuitry or logic (e.g., a dedicated processor, such as a field-programmable gate array (FPGA) or application-specific integrated circuit (ASIC)) permanently configured to perform certain operations. The hardware module may also include programmable logic or circuitry systems (e.g., included in a dedicated processor or other programmable processor) that are temporarily configured by software to perform certain operations. It should be understood that the decision to implement the hardware module in a dedicated and permanently configured circuitry system or in a temporarily configured circuitry system (e.g., configured by software) may be driven by cost and time considerations.

[0065] Therefore, the term "hardware module" should be understood to include tangible entities that are physically constructed, permanently configured (e.g., hardwired), or temporarily configured (e.g., programmed) to operate or perform certain operations described herein in a certain way. Considering embodiments where hardware modules are temporarily configured (e.g., programmed), it is not necessary to configure or instantiate each hardware module at any given time. For example, in cases where hardware modules include general-purpose processors configured using software, the general-purpose processor can be configured as different hardware modules at different times. Thus, software can configure the processor, for example, to constitute a specific module at one time and different modules at different times.

[0066] Hardware modules can provide information to or receive information from other hardware modules. Therefore, these hardware modules can be considered communicatively coupled. In the presence of multiple such hardware modules, communication can be achieved through signal transmission connecting the hardware modules (e.g., via appropriate circuitry and buses). In embodiments where multiple hardware modules are configured or instantiated at different times, communication between such hardware modules can be achieved, for example, by storing and retrieving information in a memory structure accessible to the multiple hardware modules. For example, one hardware module can perform an operation and store the output of such operation in a communicatively coupled memory device. Another hardware module can then access this memory device at a later time to retrieve and process the stored output. Hardware modules can also initiate communication with input or output devices and can operate on resources (e.g., collections of information).

[0067] The various operations of the example methods described herein can be performed, at least in part, by one or more processors that are temporarily configured (e.g., by software) or permanently configured to perform the relevant operations. Whether temporarily or permanently configured, such processors can constitute processor-implemented modules that operate to perform one or more operations or functions. In some exemplary embodiments, the modules referred to herein may include processor-implemented modules.

[0068] Similarly, the methods or routines described herein can be implemented at least in part by a processor. For example, at least some operations of a method can be performed by one or more processors or hardware modules implemented by processors. The execution of some of the operations can be distributed among one or more processors that reside not only within a single machine but are deployed across multiple machines. In some exemplary embodiments, one or more processors may be located in a single location (e.g., in a home environment, in an office environment, or as a server farm), but in other embodiments, the processors may be distributed across multiple locations.

[0069] Some of the execution in the operation can be distributed across one or more processors that reside not only within a single machine but are also deployed across multiple machines. In some exemplary embodiments, one or more processors or processor-implemented modules may be located in a single geographic location (e.g., in a home environment, an office environment, or a server farm). In other example embodiments, one or more processors or processor-implemented modules may be distributed across multiple geographic locations.

[0070] Unless otherwise expressly stated, the use of words such as “processing,” “computing,” “operating,” “determining,” “presenting,” “displaying,” etc., in this document may refer to the actions or processes of a machine (e.g., a computer) that manipulate or transform data represented as physical (e.g., electronic, magnetic, or optical) quantities within one or more memories (e.g., volatile memory, non-volatile memory, or combinations thereof), registers, or other machine components that receive, store, transmit, or display information.

[0071] As used herein, any reference to "one embodiment" or "an embodiment" means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Therefore, the phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment.

[0072] Some embodiments may be described using the terms "coupled" and "connected," along with their derivatives. For example, the term "coupled" may be used to describe some embodiments to indicate that two or more elements are in direct physical or electrical contact. However, the term "coupled" may also mean that two or more elements are not in direct contact with each other, but still cooperate or interact with each other. Embodiments are not limited to this.

[0073] Those skilled in the art will recognize that various modifications, alterations, and combinations can be made with respect to the above embodiments without departing from the scope of the invention, and such modifications, alterations, and combinations will be considered to be within the scope of the invention.

[0074] Although the invention has been described with reference to specific examples, these examples are intended to be illustrative only and not to limit the invention. It will be apparent to those skilled in the art that changes, additions and / or deletions can be made to the disclosed embodiments without departing from the spirit and scope of the invention.

[0075] The foregoing description is provided for clarity only; and should not be construed as an unnecessary limitation, as modifications within the scope of this invention will be readily apparent to those skilled in the art.

Claims

1. A method for managing access to a wireless network by a user equipment (UE) via unlicensed spectrum, the method comprising: The UE receives a signal generated by a first cell of the wireless network via the unlicensed spectrum, the signal containing an indication of the presence or absence of one or more uplink access constraints of the first cell, and the one or more uplink access constraints correspond to at least one of the following: a threshold distance between the UE and the first cell, or uplink interference detected by the first cell in a spatial direction corresponding to the UE. The UE selects the serving cell of the wireless network based on the indication; as well as The UE connects to the selected serving cell.

2. The method of claim 1, wherein receiving a signal generated by a first cell includes receiving a reference signal broadcast by the first cell, the broadcast reference signal including a first bit set used by the UE to determine a downlink interference level; and a second bit set indicating the corresponding presence or absence of the one or more uplink access constraints.

3. The method according to claim 2, wherein: The value of at least one bit in the second bit set indicates the existence of a first uplink access constraint corresponding to the threshold distance; The UE is positioned at a distance from the first cell that is greater than the threshold distance; as well as Selecting a serving cell involves selecting the serving cell from a set of candidate cells that does not include the first cell, based on the value of at least one bit in the second bit set.

4. The method according to claim 2, wherein: The uplink interference level detected by the first cell in the spatial direction corresponding to the UE is different from the downlink interference level in the spatial direction corresponding to the UE; The value of at least one bit in the second bit set indicates that the uplink interference level is greater than the uplink interference threshold; as well as Selecting the serving cell involves selecting the serving cell from a set of candidate cells that does not include the first cell, based on the value of at least one bit in the second bit set.

5. The method of claim 2, wherein the reference signal for broadcasting is a synchronization signal, and the second bit set includes reserved bits that are unspecified bits of the synchronization signal.

6. The method according to claim 1, wherein: The signal indicates the corresponding presence of one or more uplink access constraints; The method further includes the UE determining that the UE satisfies one or more uplink access constraints; as well as Selecting the serving cell includes selecting the first cell as the serving cell based on the determination.

7. The method of claim 6, further comprising: The UE determines the downlink interference level based on the received signal generated by the first cell. The selection of the first cell as the serving cell is further based on the determined downlink interference level.

8. The method according to claim 1, wherein: The received signal is a first signal generated by the first cell, and the first signal indicates the corresponding presence of the one or more uplink access constraints; The method further includes determining, by the UE, that the UE does not satisfy at least one of the one or more uplink access constraints, and based on the determination that the UE does not satisfy at least one of the one or more uplink access constraints: After the duration has elapsed, the UE processes a second signal generated by the first cell, the second signal containing an update of the indication of the corresponding presence or absence of the one or more uplink access constraints; as well as The UE determines that it satisfies all current uplink access constraints indicated by the update; as well as Selecting the serving cell includes selecting the first cell as the serving cell based on the determination that the UE satisfies all current uplink access constraints indicated by the update.

9. The method of claim 1, wherein the UE is an aircraft in flight, and the wireless network is an in-flight connected wireless network.

10. A method for managing access to a wireless network by a user equipment (UE) via unlicensed spectrum, the method comprising: A reference signal having a first part and a second part is transmitted by a cell site of the wireless network in the unlicensed spectrum. The first part is used by the UE to determine downlink interference. The second part includes a set of reserved bits with no specified use for the reference signal. The set of reserved bits has values ​​indicating the presence or absence of one or more uplink access constraints specific to the cell site, and the one or more uplink access constraints correspond to at least one of the following: a threshold distance between the UE and the cell site, or uplink interference detected by the cell site in a spatial direction corresponding to the UE. The UE determines whether to communicatively connect to the cell site based on the reference signal.

11. The method of claim 10, wherein the transmitted reference signal comprises a broadcast synchronization signal.

12. The method of claim 10, wherein the UE is an aircraft in flight, and the wireless network is an in-flight connected wireless network.

13. The method of claim 10, wherein: The method further includes determining the level of uplink interference within the unlicensed spectrum by the cell site; as well as The transmission of a reference signal having a first portion and a second portion includes the transmission of at least one reserved bit having a value indicating that the level of the uplink interference is greater than an interference threshold, the second portion including the set of reserved bits having a value indicating the corresponding presence or absence of the one or more uplink access constraints.

14. The method of claim 13, wherein: Determining the uplink interference level includes determining a specific uplink interference level for each of a plurality of spatial directions served by the cell site; as well as Transmitting the reference signal having the first portion and the second portion includes transmitting a corresponding reference signal comprising the first portion and a corresponding second portion in each spatial direction, the second portion comprising at least one reserved bit having a value indicating that the uplink interference level is greater than the interference threshold, and the corresponding second portion comprising at least one reserved bit having a value indicating whether the uplink interference level specific to each spatial direction is greater than the interference threshold.

15. The method of claim 13, wherein: The at least one reserved bit having the value indicating that the uplink interference level is greater than the interference threshold is a first at least one reserved bit; as well as The transmission of a reference signal having a first portion and a second portion includes the transmission of at least a second reserved bit, the second portion including the set of reserved bits having values ​​indicating the corresponding presence or absence of the one or more uplink access constraints, the second at least a reserved bit having values ​​indicating the presence or absence of a threshold distance between the UE and the cell site.

16. The method of claim 10, wherein: The transmission of a reference signal having a first part and a second part includes transmitting at least one reserved bit, the second part including a set of reserved bits having values ​​indicating the corresponding presence or absence of the one or more uplink access constraints, the at least one reserved bit having a value indicating the presence of a threshold distance between the UE and the cell site; as well as When the spatial distance between the UE and the cell site is less than or equal to the threshold distance, the UE communicatively connects to the cell site.

17. The method of claim 16, wherein the cell site is at least one of the following: configured to utilize a time-division duplex (TDD) frame configuration optimized for a UE located within the threshold distance of the cell site, or configured as a high-capacity cell within the wireless network.

18. The method of claim 16, wherein: The at least one reserved bit having the value indicating the existence of the threshold distance between the UE and the cell site is a first at least one reserved bit; as well as The transmission of a reference signal having a first portion and a second portion includes the transmission of at least a second reserved bit, the second portion including the set of reserved bits having values ​​indicating the presence or absence of the one or more uplink access constraints, the second at least a reserved bit having values ​​indicating whether the uplink interference level is greater than an interference threshold.

19. The method of claim 18, further comprising detecting the uplink interference level by the cell site.

20. The method of claim 19, wherein: Detecting the uplink interference level includes detecting the corresponding uplink interference level for each of a plurality of spatial directions served by the cell site; as well as Transmitting the reference signal having a second portion including the second at least one reserved bit includes transmitting a corresponding reference signal having a second portion including a corresponding second at least one reserved bit in each spatial direction, the second at least one reserved bit having a value indicating whether the uplink interference level is greater than the interference threshold, the corresponding second at least one reserved bit having a value indicating whether the corresponding uplink interference level specific to each spatial direction is greater than the interference threshold.

21. The method of claim 10, further comprising: An updated reference signal is transmitted within the unlicensed spectrum, the updated reference signal having a first portion which is used by the UE to determine downlink interference; And a second part, the second part comprising the set of reserved bits having updated values, the updated values ​​indicating an update on the corresponding presence or absence of the one or more uplink access constraints specific to the cell site. The UE determines whether to communicatively connect to the cell site based on the updated reference signal.

22. A user equipment (UE), comprising: One or more memory units; as well as One or more processors, the processors being configured to execute instructions stored in the one or more memories to: The UE receives a signal generated by a first cell of a wireless network via an unlicensed spectrum, the signal containing an indication of the presence or absence of one or more uplink access constraints of the first cell, and the one or more uplink access constraints correspond to at least one of the following: a threshold distance between the UE and the first cell, or uplink interference detected by the first cell in a spatial direction corresponding to the UE. The UE selects the serving cell of the wireless network based on the indication; as well as The UE connects to the selected serving cell.

23. The UE according to claim 22, wherein, In order to receive the signal generated by the first cell, the one or more processors are configured to execute instructions to: The UE receives a reference signal broadcast by the first cell, the broadcast reference signal comprising a first bit set used by the UE to determine the downlink interference level and a second bit set indicating the corresponding presence or absence of the one or more uplink access constraints.

24. Cell sites for wireless networks, including: One or more memory units; as well as One or more processors, the processors being configured to execute instructions stored in the one or more memories to: A reference signal having a first portion and a second portion is transmitted by a cell site of the wireless network via unlicensed spectrum. The first portion is used by a user equipment (UE) to determine downlink interference. The second portion includes a set of reserved bits with no specified use for the reference signal, the set of reserved bits having values ​​indicating the presence or absence of one or more uplink access constraints specific to the cell site, and the one or more uplink access constraints corresponding to at least one of the following: a threshold distance between the UE and the cell site, or uplink interference detected by the cell site in a spatial direction corresponding to the UE. The UE determines whether to communicatively connect to the cell site based on the reference signal.

25. The cell site according to claim 24, wherein, In order to transmit the reference signal, the one or more processors are configured to execute instructions to: Broadcast synchronization signal.

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