Asynchronous carrier aggregation

Abstract

Methods, systems, and devices are described that facilitate wireless communications including asynchronous carrier aggregation between high-band transmissions and lower-band transmissions. A user equipment (UE) can be configured to monitor transmissions in a first band and a second band. The UE can measure a timing difference between a transmission in the first band and one or more transmissions in the second band and transmit an indication of the timing difference to a base station. The base station can use the timing difference to determine whether the UE will use asynchronous carrier aggregation. If the base station determines that the UE will use asynchronous carrier aggregation, the base station can configure the UE to observe at least a minimum amount of delay when signaling uplink via one of the bands.

Description

[0001] This application is a divisional application of Chinese patent application No. 201880065043.4, filed on October 8, 2018, entitled "Asynchronous Carrier Aggregation".

[0002] Cross-references

[0003] This patent application claims the benefits of the following applications: U.S. Provisional Patent Application No. 62 / 569,826, entitled "Asynchronous Carrier Aggregation," filed October 9, 2017, by Yerramalli et al.; and U.S. Patent Application No. 16 / 153,166, entitled "Asynchronous Carrier Aggregation," filed October 5, 2018, by Yerramalli et al.; each of the aforementioned applications is assigned to the assignee of this application. Technical Field

[0004] In summary, the following text refers to wireless communication, and more specifically, asynchronous carrier aggregation. Background Technology

[0005] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, and broadcasting. These systems can support communication with multiple users by sharing available system resources (e.g., time, frequency, or power). Examples of such multiple access systems include fourth-generation (4G) systems (such as Long Term Evolution (LTE) systems or improved LTE (LTE-A) systems) and fifth-generation (5G) systems (which may be referred to as New Radio (NR) systems). These systems can employ technologies 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 Spectrum OFDM (DFT-S-OFDM). Wireless multiple access communication systems can include multiple base stations or network access nodes, each supporting communication with multiple communication devices (which may also be referred to as User Equipment (UE)) simultaneously.

[0006] In some systems, multiple connections can be established between the UE and one or more base stations. In some cases, low-frequency carriers can be used for low-band connections, and relatively high-frequency carriers can be used for high-frequency connections. In some deployments, the low-frequency and high-frequency carriers may not be time-synchronized; for example, a first base station may support a low-frequency carrier, and a second base station may support a high-frequency carrier, and transmissions to or from the first base station may not be time-synchronized with transmissions to or from the second base station. Efficient techniques for communication on asynchronous carriers are desirable. Summary of the Invention

[0007] The described technology relates to improved methods, systems, devices, or apparatuses supporting carrier aggregation (CA) using asynchronous carriers. In summary, the described technology provides for monitoring transmissions at a user equipment (UE) in a first frequency band and a second frequency band, the second band being at a higher frequency than the first band. The UE can use a first carrier in the first frequency band to establish a connection, and the UE can measure a timing difference between transmissions in the first frequency band and one or more transmissions in the second frequency band. The UE can send an indication of the timing difference to a base station, and the base station can determine, at least in part, the connection mode the UE will use to establish a connection using a second carrier in the second frequency band based on the timing difference. For example, the base station can use the timing difference to determine whether the UE will use a dual-connectivity mode, a synchronous CA mode, or an asynchronous CA mode to establish a connection using a second carrier in the second frequency band.

[0008] If the base station determines that the UE will use asynchronous CA mode, the base station can configure the UE to observe at least a minimum reporting delay between receiving downlink transmissions via a second carrier and transmitting associated uplink transmissions via a first carrier. For example, the base station can configure the UE to observe at least a minimum delay between receiving packets via a second carrier and reporting (e.g., transmitting) acknowledgments for the packets via a first carrier. As another example, the base station can configure the UE to observe a minimum delay between receiving packets via a second carrier and reporting (e.g., transmitting) channel state information (CSI) corresponding to the packets via a first carrier.

[0009] A method for wireless communication is described. The method may include: establishing a first connection with a UE using a first carrier in a first frequency band; receiving from the UE a timing difference between a transmission in the first frequency band and one or more transmissions in a second frequency band higher than the first frequency band; and determining, at least in part, based on the timing difference, that the UE intends to use an asynchronous carrier aggregation mode for communication using a second carrier in the second frequency band.

[0010] An apparatus for wireless communication is described. The apparatus may include: a unit for establishing a first connection with a UE using a first carrier in a first frequency band; a unit for receiving from the UE a timing difference between a transmission in the first frequency band and one or more transmissions in a second frequency band higher than the first frequency band; and a unit for determining, at least in part, based on the timing difference, that the UE intends to use an asynchronous carrier aggregation mode for communication using a second carrier in the second frequency band.

[0011] Another apparatus for wireless communication is described. The apparatus may include a processor, a memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be operable to cause the processor to: establish a first connection with a UE using a first carrier in a first frequency band; receive from the UE a timing difference between a transmission in the first frequency band and one or more transmissions in a second frequency band higher than the first frequency band; and determine, at least in part, based on the timing difference, that the UE intends to use an asynchronous carrier aggregation mode for communication using a second carrier in the second frequency band.

[0012] A non-transitory computer-readable medium for wireless communication is described. The non-transitory computer-readable medium may include instructions operable to cause a processor to: establish a first connection with a UE using a first carrier in a first frequency band; receive from the UE a timing difference between a transmission in the first frequency band and one or more transmissions in a second frequency band higher than the first frequency band; and determine, at least in part, based on the timing difference, that the UE intends to use an asynchronous carrier aggregation mode for communication using a second carrier in the second frequency band.

[0013] Some examples of the above-described methods, apparatuses, and non-transitory computer-readable media may also include procedures, features, units, or instructions for performing the following: configuring the UE to observe at least a minimum delay between receiving a packet via the second carrier and reporting an acknowledgment for the packet via the first carrier, based at least in part on the determination that the UE will use the asynchronous carrier aggregation mode. Some examples of the above-described methods, apparatuses, and non-transitory computer-readable media may also include procedures, features, units, or instructions for performing the following: determining the minimum delay based at least in part on the following: the timing difference, the first subcarrier spacing associated with the first carrier, the second subcarrier spacing associated with the second carrier, or any combination thereof.

[0014] In some examples of the methods, apparatuses, and non-transitory computer-readable media described above, the timing difference may include a timing offset between a first reference time slot on the first carrier and a second reference time slot on the second carrier, and some examples of the methods, apparatuses, and non-transitory computer-readable media may also include a process, feature, unit, or instruction for determining the minimum delay based at least in part on the timing difference, the duration of the first time slot for the first carrier, the duration of the second time slot for the second carrier, uplink timing advance for the first carrier, the duration of the uplink portion of a time slot in the first carrier, the processing time for the packet, or any combination thereof.

[0015] In some examples of the methods, apparatus, and non-transitory computer-readable media described above, the timing difference may include a timing offset between a first reference time slot on the first carrier and a second reference time slot on the second carrier, and some examples of the methods, apparatus, and non-transitory computer-readable media may also include procedures, features, units, or instructions for performing the following operations: applying a rounding function to a quantity based at least in part on: the timing difference, the duration of the first time slot for the first carrier, the duration of the second time slot for the second carrier, uplink timing advance for the first carrier, the duration of the uplink portion of the time slot in the first carrier, the processing time for the packet, or any combination thereof; and configuring acknowledgment reporting parameters for the UE based at least in part on the output of the rounding function. In some examples, the duration of the second time slot for the second carrier is for the downlink portion of the time slot in the second carrier. In some examples, the duration of the uplink portion of the time slot in the first carrier is based at least in part on the amount of uplink data to be transmitted in the time slot in the first carrier.

[0016] Some examples of the methods, apparatuses and non-transitory computer-readable media described above may also include processes, features, units or instructions for performing the following: configuring the UE to report the acknowledgment via the Physical Uplink Shared Channel (PUSCH) or the Physical Uplink Control Channel (PUCCH).

[0017] Some examples of the methods, apparatuses and non-transitory computer-readable media described above may also include processes, features, units or instructions for performing the following: configuring the UE to at least partially use the Radio Resource Control (RRC) protocol to observe at least the minimum latency.

[0018] Some examples of the methods, apparatuses and non-transitory computer-readable media described above may also include processes, features, units or instructions for performing the following: receiving an updated timing difference from the UE; and configuring the UE to observe at least a minimum delay between receiving a subsequent packet via the second carrier and reporting an acknowledgment for the subsequent packet via the first carrier.

[0019] In some examples of the methods, apparatuses and non-transitory computer-readable media described above, the timing difference may include: a timing offset between a first subframe on the first carrier and a second subframe on the second carrier, a timing offset between a first timeslot on the first carrier and a second timeslot on the second carrier, a timing offset between a first symbol on the first carrier and a second symbol on the second carrier, a timing offset between one or more samples corresponding to the first symbol on the first carrier and one or more samples corresponding to the second symbol on the second carrier, or any combination thereof.

[0020] Some examples of the methods, apparatuses and non-transitory computer-readable media described above may also include processes, features, units or instructions for performing the following: configuring the UE to observe at least a minimum delay between receiving a packet via the second carrier and reporting a CSI corresponding to the packet via the first carrier, based at least in part on the determination that the UE will use the asynchronous carrier aggregation mode.

[0021] In some examples of the methods, apparatuses, and non-transitory computer-readable media described above, determining whether the UE intends to use the asynchronous carrier aggregation mode for communication using the second carrier in the second frequency band, based at least in part on the timing difference, may include comparing the timing difference with a threshold timing difference. Some examples of the methods, apparatuses, and non-transitory computer-readable media described above may also include procedures, features, units, or instructions for determining the threshold timing difference based at least in part on the subcarrier spacing associated with the first frequency band or the second frequency band.

[0022] In some examples of the methods, apparatuses and non-transitory computer-readable media described above, it is determined whether the UE intends to use the asynchronous carrier aggregation mode for communication using the second carrier in the second frequency band or at least in part based on the frequency difference between the first frequency band and the second frequency band.

[0023] In some examples, determining whether the UE should use the asynchronous carrier aggregation mode for communication using the second carrier in the second frequency band is based at least in part on whether the UE can establish an uplink connection on the second carrier. Examples of the above methods, apparatuses, and non-transitory computer-readable media may also include procedures, features, units, or instructions for performing the following: comparing a channel quality metric for the second carrier with a threshold value to determine whether the UE can establish the uplink connection on the second carrier. Examples of the above methods, apparatuses, and non-transitory computer-readable media may also include procedures, features, units, or instructions for performing the following: receiving an indication from the UE regarding whether the UE can establish the uplink connection on the second carrier. Examples of the above methods, apparatuses, and non-transitory computer-readable media may also include procedures, features, units, or instructions for performing the following: configuring the UE to attempt a random access procedure via the second carrier using a specified transmit power to determine whether the UE can establish the uplink connection on the second carrier.

[0024] In some examples of the methods, apparatuses, and non-transitory computer-readable media described above, determining whether the UE intends to use the asynchronous carrier aggregation mode for communication using the second carrier in the second frequency band, based at least in part on the timing difference, may include: determining whether the second carrier can be aggregated with the first carrier. In some examples, determining whether the second carrier can be aggregated with the first carrier may include: determining the quality of the backhaul connection between a first base station corresponding to the first carrier and a second base station corresponding to the second carrier.

[0025] A method for wireless communication is described. The method may include: establishing a first connection with a base station using a first carrier in a first frequency band; monitoring one or more transmissions in a second frequency band, the second frequency band being at a higher frequency than the first frequency band; measuring a timing difference between the transmissions in the first frequency band and the one or more transmissions in the second frequency band; sending an indication of the timing difference to the base station; and receiving from the base station an indication regarding using an asynchronous carrier aggregation mode for communication utilizing a second carrier in the second frequency band.

[0026] An apparatus for wireless communication is described. The apparatus may include: a unit for establishing a first connection with a base station using a first carrier in a first frequency band; a unit for monitoring one or more transmissions in a second frequency band at a higher frequency than the first frequency band; a unit for measuring a timing difference between a transmission in the first frequency band and the one or more transmissions in the second frequency band; a unit for sending an indication of the timing difference to the base station; and a unit for receiving from the base station an indication regarding using an asynchronous carrier aggregation mode for communication utilizing a second carrier in the second frequency band.

[0027] Another apparatus for wireless communication is described. The apparatus may include a processor, a memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be operable to cause the processor to: establish a first connection with a base station using a first carrier in a first frequency band; monitor one or more transmissions in a second frequency band at a higher frequency than the first frequency band; measure a timing difference between the transmissions in the first frequency band and the one or more transmissions in the second frequency band; send an indication of the timing difference to the base station; and receive from the base station an indication to use an asynchronous carrier aggregation mode for communication utilizing a second carrier in the second frequency band.

[0028] A non-transitory computer-readable medium for wireless communication is described. The non-transitory computer-readable medium may include instructions operable to cause a processor to: establish a first connection with a base station using a first carrier in a first frequency band; monitor one or more transmissions in a second frequency band at a higher frequency than the first frequency band; measure a timing difference between the transmissions in the first frequency band and the one or more transmissions in the second frequency band; send an indication of the timing difference to the base station; and receive from the base station an indication to use an asynchronous carrier aggregation mode for communication utilizing a second carrier in the second frequency band.

[0029] Some examples of the methods, apparatuses and non-transitory computer-readable media described above may also include processes, features, units or instructions for performing the following: receiving from the base station the minimum delay to be observed between receiving a packet via the second carrier and reporting an acknowledgment for the packet via the first carrier.

[0030] Some examples of the methods, apparatuses and non-transitory computer-readable media described above may also include processes, features, units or instructions for performing the following operations: sending an updated timing difference to the base station; and receiving from the base station a minimum delay for an update to be observed between receiving a subsequent packet via the second carrier and reporting an acknowledgment for the subsequent packet via the first carrier.

[0031] Some examples of the methods, apparatuses and non-transitory computer-readable media described above may also include processes, features, units or instructions for performing the following operations: measuring uplink timing advance for the first carrier; and sending an indication of the uplink timing advance to the base station.

[0032] Some examples of the methods, apparatuses and non-transitory computer-readable media described above may also include processes, features, units or instructions for performing the following operations: measuring the processing time for the packet; and sending an indication of the processing time to the base station.

[0033] Some examples of the above-described methods, apparatuses, and non-transitory computer-readable media may also include processes, features, units, or instructions for performing the following operations: measuring the duration of a second timeslot for the second carrier; and sending an indication to the base station of the duration of the second timeslot for the second carrier. Some examples of the above-described methods, apparatuses, and non-transitory computer-readable media may also include processes, features, units, or instructions for performing the following operations: measuring at least one of uplink timing advance for the first carrier, processing time for the packet, or duration of the second timeslot for the second carrier; and sending an indication to the base station of at least one of the uplink timing advance, the processing time, or duration of the second timeslot for the second carrier.

[0034] Some examples of the methods, apparatuses and non-transitory computer-readable media described above may also include processes, features, units or instructions for performing the confirmation via PUSCH or PUCCH.

[0035] Some examples of the methods, apparatuses and non-transitory computer-readable media described above may also include processes, features, units or instructions for receiving the minimum delay at least in part via the RRC protocol.

[0036] In some examples of the methods, apparatuses and non-transitory computer-readable media described above, the timing difference may include: a timing offset between a first subframe on the first carrier and a second subframe on the second carrier, a timing offset between a first timeslot on the first carrier and a second timeslot on the second carrier, a timing offset between a first symbol on the first carrier and a second symbol on the second carrier, a timing offset between one or more samples corresponding to the first symbol on the first carrier and one or more samples corresponding to the second symbol on the second carrier, or any combination thereof.

[0037] Some examples of the methods, apparatuses and non-transitory computer-readable media described above may also include processes, features, units or instructions for performing the following: receiving from the base station a second minimum delay to be observed between receiving a packet via the second carrier and reporting a CSI corresponding to the packet via the first carrier.

[0038] In some examples of the methods, apparatuses and non-transitory computer-readable media described above, measuring the timing difference may include deriving the timing difference based at least in part on a common timing reference used for measuring the timing of transmissions in both the first and second frequency bands.

[0039] Some examples of the methods, apparatuses and non-transitory computer-readable media described above may also include processes, features, units or instructions for measuring the timing difference at a sampling rate associated with the second frequency band.

[0040] Some examples of the methods, apparatuses and non-transitory computer-readable media described above may also include processes, features, units or instructions for performing the following operation: sending a channel quality metric for the second carrier to the base station.

[0041] Some examples of the above-described methods, apparatuses, and non-transitory computer-readable media may further include processes, features, units, or instructions for performing the following operations: sending an indication to the base station regarding whether the uplink connection on the second carrier can be established. Some examples of the above-described methods, apparatuses, and non-transitory computer-readable media may further include processes, features, units, or instructions for performing the following operations: determining whether the uplink connection on the second carrier can be established based at least in part on comparing a radio frequency illumination level associated with the uplink connection on the second carrier to a maximum permissible illumination level. Some examples of the above-described methods, apparatuses, and non-transitory computer-readable media may further include processes, features, units, or instructions for performing the following operations: determining whether the uplink connection on the second carrier can be established based at least in part on comparing a battery charge level associated with the UE to a minimum battery charge level. Some examples of the above-described methods, apparatuses, and non-transitory computer-readable media may further include processes, features, units, or instructions for performing the following operations: receiving a specified transmit power from the base station; attempting a random access procedure via the second carrier using the specified transmit power; and determining whether the uplink connection on the second carrier can be established based at least in part on whether the random access procedure is successful. Some examples of the methods, apparatuses and non-transitory computer-readable media described above may also include processes, features, units or instructions for performing the following operations: determining whether the uplink connection on the second carrier can be established based at least in part on at least one of the following: comparing the radio frequency illumination level associated with the uplink connection on the second carrier with a maximum permissible illumination level, or comparing the battery charge level associated with the UE with a minimum battery charge level.

[0042] In some examples of the methods, apparatuses and non-transitory computer-readable media described above, the indication of the timing difference is sent in a Media Access Control (MAC) control element (MAC-CE) or in an RRC measurement report. Attached Figure Description

[0043] Figure 1 Examples of systems for wireless communication that support asynchronous carrier aggregation (CA) according to various aspects of this disclosure are shown.

[0044] Figure 2 Examples of wireless communication systems supporting asynchronous CA are shown in accordance with various aspects of this disclosure.

[0045] Figure 3 Examples of band timing that support asynchronous CA according to various aspects of this disclosure are shown.

[0046] Figure 4 An example of reporting delays supporting asynchronous CA is shown in accordance with various aspects of this disclosure.

[0047] Figure 5 An example of reporting delays supporting asynchronous CA is shown in accordance with various aspects of this disclosure.

[0048] Figure 6 An example of a process flow supporting asynchronous CA is shown in accordance with various aspects of this disclosure.

[0049] Figures 7 to 9 A block diagram of a device supporting asynchronous CA is shown, according to various aspects of this disclosure.

[0050] Figure 10 A block diagram of a system including a base station supporting asynchronous CA is shown, according to various aspects of this disclosure.

[0051] Figures 11 to 13 A block diagram of a device supporting asynchronous CA is shown, according to various aspects of this disclosure.

[0052] Figure 14 A block diagram of a system including a UE supporting asynchronous CA is shown, according to various aspects of this disclosure.

[0053] Figures 15 to 18 Methods for asynchronous CA are shown according to various aspects of this disclosure. Detailed Implementation

[0054] Various described techniques provide methods for determining whether a user equipment (UE) uses carrier aggregation (CA), and if so, implementing asynchronous CA. In some cases, the UE may use a first carrier in a first frequency band to establish a connection, and the UE may measure the timing difference between transmissions in the first frequency band and one or more transmissions in a second frequency band. The second frequency band may be relatively higher than the first frequency band. The UE may send an indication of the timing difference to the base station, and the base station may determine, at least in part, the connection mode the UE will use to establish a connection using a second carrier in the second frequency band based on the timing difference. For example, the base station may use the timing difference to determine whether the UE will use a dual-connectivity mode, a synchronous CA mode, or an asynchronous CA mode to establish a connection using a second carrier in the second frequency band. If the base station determines that the UE will use an asynchronous CA mode, the base station may configure the UE to utilize at least a minimum reporting delay between receiving data via the second carrier and sending an acknowledgment of the data via the first carrier.

[0055] As described above, in some cases, two or more carriers can be established between the UE and one or more base stations. For example, a first carrier can be established in a low-frequency band (e.g., 600 MHz or lower), which may be referred to as a low-frequency carrier, and a second carrier can be established in a high-frequency band (e.g., 4 GHz or higher, or millimeter-wave (mmW) band), which may be referred to as a high-frequency carrier. In some LTE and NR communication systems (e.g., licensed LTE and NR communication systems), signaling and feedback in CA connection mode are performed using the assumption that the aggregated carriers are time-synchronized.

[0056] However, in some deployments, the assumption that different carriers are time-synchronized may not hold. For example, in some deployments, unlicensed or shared radio spectrum may be used for one or more component carriers (CCs) or enhanced component carriers (eCCs), and in some cases, base stations may operate in non-carrier deployments where not all base stations are operated by a mobile network operator (MNO) or the same MNO. Furthermore, in some cases, base stations supporting high-frequency band carriers may be located indoors and may not have reliable access to another system that can provide timing synchronization (e.g., GPS signals may not be reliably received). Additionally or alternatively, in some cases, backhaul communication between base stations may not be reliably used for timing synchronization due to unpredictable delays between the clock sources of the base stations. In some cases, under one or more synchronization protocols (e.g., IEEE 1588), the source clocks at low-frequency and high-frequency band carriers may not meet delay requirements. In some cases, high-frequency band carriers may operate in low-power mode or be completely shut down due to maximum permissible illumination requirements (e.g., when a human hand is detected on or near the communication path of the high-frequency band carrier). Furthermore, in some cases, low-frequency or high-frequency carriers can be shut down to reduce interference.

[0057] As another example, in some cases, a UE may have a low-frequency band connection to a base station or cell, which may be an anchor carrier connection. In some cases, a low-frequency band cell can provide umbrella-style low-frequency band connections for multiple high-frequency band cells (e.g., mmW cells). Due to the attenuation and directional transmission of high-frequency band cells, in some cases, a high-frequency band cell may not be able to detect the transmissions of other high-frequency band cells. Furthermore, in some cases, a low-frequency band cell may be able to detect the transmissions of other low-frequency band cells, which may be sufficiently synchronized for low-frequency band transmissions; however, due to the relative improvement in timing accuracy at higher frequencies, such low-frequency band synchronization may not provide sufficient accuracy for the synchronization of high-frequency band cells that may coexist with low-frequency band cells. For example, low-frequency band transmissions and high-frequency band transmissions may use different subcarrier spacings (SCS) and different timing requirements. Therefore, if the low-frequency carriers are synchronized within ±2 microseconds, such a timing difference can be equal to the offset of one or more orthogonal frequency division multiplexing (OFDM) symbols in the high-frequency carriers (e.g., a high-frequency carrier with a 480kHz tone interval will have a 1 OFDM symbol offset at a timing difference of + / -2μs, and a high-frequency carrier with a 960kHz tone interval will have a 2 OFDM symbol offset at a timing difference of + / -2μs). Furthermore, even if two cells are synchronized, they may lose synchronization over time (e.g., due to oscillator drift).

[0058] Advantageously, the asynchronous CA technique presented herein does not rely on the assumption that different carriers are time-synchronized. Therefore, the technique described herein can provide the advantages of CA in deployments where different carriers may not be time-synchronized (e.g., carriers supported by two or more base stations or corresponding to different frequency bands may not be synchronized within a predictable delay, such as as required by synchronization protocols (e.g., IEEE 1588). The UE can measure and report the timing difference between transmissions at two different frequencies (e.g., low-band transmission and high-band transmission). For example, the UE can measure the timing difference between a reference timing unit (e.g., subframe, time slot, etc.) of a low-band carrier and a reference timing unit (e.g., subframe, time slot, etc.) of a high-band carrier. In some cases, the UE can also measure one or more channel quality metrics (e.g., Reference Received Power (RSRP), Reference Received Quality (RSRQ), Channel Quality Indicator (CQI), etc.) or one or more beam management parameters of the high-band carrier and report the channel quality metric or beam management parameter along with the cell identifier (ID) of the high-band carrier. The UE can then send the measured timing offset, cell ID, and channel quality report to the base station. In some examples, the low-band carrier and the high-band carrier can be considered aggregated carriers. For example, acknowledgments, CQI, beam management parameters, or other uplink signals and information associated with the high-band carrier can be transmitted on the low-band carrier, and in some cases, such uplink signals can be transmitted alternatively on the PUSCH on the high-band carrier (e.g., in dual connectivity mode). The base station receiving the timing difference can determine whether the UE should use asynchronous CA (as opposed to, for example, synchronous CA or dual connectivity with independent uplink and downlink connections on each carrier) based at least in part on the timing difference.

[0059] For example, a base station may determine whether a UE should use asynchronous CA based at least in part on comparing a timing difference with a threshold timing difference, which may depend in part on the SCS of different transmissions. The base station may also determine whether a UE should use asynchronous CA based at least in part on the frequency difference between two candidate carriers (including whether the carriers are part of a single frequency band). The base station may also determine whether a UE should use asynchronous CA based at least in part on whether the UE can establish an uplink connection on one of the carriers. The base station may also determine whether a UE should use asynchronous CA based at least in part on whether the different carriers belong to base stations that support aggregation with each other (e.g., whether the backhaul between corresponding base stations has sufficient quality to support CA).

[0060] If the base station determines that the UE will use asynchronous CA, the base station can configure the UE to utilize the minimum delay between receiving downlink transmissions via a second carrier (e.g., a high-frequency band carrier) and transmitting the associated uplink transmissions via a first carrier (e.g., a low-frequency band carrier). For example, the base station can configure the UE to observe at least a minimum reporting delay between receiving a packet via the second carrier and reporting an acknowledgment for that packet via the first carrier. The base station can determine the minimum reporting delay based at least in part on the SCS of the first carrier and the timing difference between the two carriers. Subsequently, the UE can continue to monitor the timing difference and, if the timing difference drifts over time, update one or more base stations supporting the aggregated carriers, in which case the one or more base stations can update the minimum reporting delay to be used by the UE. The base station can similarly configure the UE to observe at least a minimum delay when performing other uplink signaling (such as channel state information (CSI), beam management information, power control information, etc.) via the first carrier.

[0061] The UE can derive the timing difference, at least in part, based on a common timing reference used to measure the timing of both high-frequency and low-frequency transmissions. In some cases, the UE can measure and report the timing difference based on the sampling rate associated with the high-frequency transmission. The UE can provide a report including the measured timing difference, for example, in a Media Access Control (MAC) element (CE) or in a Radio Resource Control (RRC) measurement report.

[0062] First, various aspects of this disclosure are described within the context of a wireless communication system. Then, various timing aspects and process flows are described. These aspects are further illustrated and described with reference to apparatus diagrams, system diagrams, and flowcharts relating to asynchronous CA.

[0063] Figure 1Examples of a wireless communication system 100 according to various aspects of this disclosure are shown. The wireless communication system 100 includes a base station 105, a UE 115, and a core network 130. In some examples, the wireless communication system 100 may be a Long Term Evolution (LTE) network, an improved LTE (LTE-A) network, or a New Radio (NR) network. In some cases, the wireless communication system 100 may support enhanced broadband communication, ultra-reliable (e.g., mission-critical) communication, low-latency communication, or communication with low-cost and low-complexity devices. In some cases, one or more UEs 115 may provide one or more base stations 105 with an indication of timing differences between carriers, and based at least in part on the indicated timing differences, the base station 105 may determine that the UE 115 will use asynchronous CA to establish communication on multiple carriers. The base station 105 may also configure the UE 115 to use asynchronous CA at least in part by configuring the UE 115 to observe at least a minimum delay in uplink signaling via the anchor carrier.

[0064] Base station 105 can wirelessly communicate with UE 115 via one or more base station antennas. Base station 105 described herein may include, or may be referred to by those skilled in the art as, a base transceiver, wireless base station, access point, wireless transceiver, Node B, evolved Node B (eNB), next-generation Node B, or gigabit Node B (both may be referred to as gNB), home Node B, home evolved Node B, or some other suitable term. Wireless communication system 100 may include different types of base stations 105 (e.g., macro cell base stations or small cell base stations). UE 115 described herein is capable of communicating with various types of base stations 105 and network devices (including macro eNBs, small cell eNBs, gNBs, relay base stations, etc.).

[0065] Each base station 105 may be associated with a specific geographic coverage area 110 in which communication with each UE 115 is supported. Each base station 105 may provide communication coverage to the corresponding geographic coverage area 110 via a communication link 125, and the communication link 125 between the base station 105 and the UE 115 may utilize one or more carriers. The communication link 125 shown in the wireless communication system 100 may include: an uplink transmission from the UE 115 to the base station 105, or a downlink transmission from the base station 105 to the UE 115. The downlink transmission may also be referred to as a forward link transmission, and the uplink transmission may also be referred to as a reverse link transmission.

[0066] The geographic coverage area 110 for base station 105 can be divided into sectors, each sector constituting only a portion of the geographic coverage area 110, and each sector can be associated with a cell. For example, each base station 105 can provide communication coverage for macro cells, small cells, hotspots, or other types of cells, or various combinations thereof. In some examples, base station 105 can be mobile, and therefore, communication coverage is provided for mobile geographic coverage areas 110. In some examples, different geographic coverage areas 110 associated with different technologies can overlap, and overlapping geographic coverage areas 110 associated with different technologies can be supported by the same base station 105 or different base stations 105. The wireless communication system 100 can include, for example, heterogeneous LTE / LTE-A or NR networks, where different types of base stations 105 provide coverage for individual geographic coverage areas 110.

[0067] The term "cell" refers to a logical communication entity used for communication with base station 105 (e.g., on a carrier) and may be associated with an identifier (e.g., Physical Cell Identifier (PCID), Virtual Cell Identifier (VCID)) used to distinguish neighboring cells operating via the same or different carriers. In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., Machine-Type Communication (MTC), Narrowband Internet of Things (NB-IoT), Enhanced Mobile Broadband (eMBB), or other protocol types) that can provide access for different types of devices. In some cases, the term "cell" may refer to a portion (e.g., a sector) of the geographical coverage area 110 on which the logical entity operates.

[0068] UE 115 may be distributed throughout the wireless communication system 100, and each UE 115 may be stationary or mobile. UE 115 may also be referred to as a mobile device, wireless device, remote device, handheld device, or user equipment, or some other suitable term, wherein "device" may also be referred to as a cell, station, terminal, or client. UE 115 may also be a personal electronic device, such as a cellular phone, personal digital assistant (PDA), tablet computer, laptop computer, or personal computer. In some examples, UE 115 may also refer to a wireless local loop (WLL) station, Internet of Things (IoT) device, Internet of Everything (IoE) device, or MTC device, which may be implemented in various items such as appliances, vehicles, instruments, etc.

[0069] Some UE 115s (such as MTC or IoT devices) can be low-cost or low-complexity devices and can provide automated machine-to-machine communication (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 base station 105 without human intervention. In some examples, M2M communication or MTC can include communication from devices that have integrated sensors or meters to measure or capture information and relay that information to a central server or application that can utilize the information or present it to humans interacting with the program or application. Some UE 115s can be designed to collect information or enable automated machine behavior. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, climate and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based billing.

[0070] Some UEs 115 can be configured to operate in reduced-power modes, such as half-duplex communication (e.g., a mode that supports unidirectional communication via either transmission or reception, rather than simultaneous transmission and reception). In some examples, half-duplex communication may be performed at a reduced peak rate. Other power-saving techniques for UE 115 include entering a power-saving "deep sleep" mode when not engaged in active communication or operating on limited bandwidth (e.g., according to narrowband communication). In some cases, UE 115 may be designed to support critical functions (e.g., mission-critical functions), and the wireless communication system 100 may be configured to provide ultra-reliable communication for these functions.

[0071] In some cases, UE 115 can also communicate directly with other UE 115 (e.g., using peer-to-peer (P2P) or device-to-device (D2D) protocols). One or more UE 115s in a group utilizing D2D communication can be within the geographic coverage area 110 of base station 105. Other UE 115s in such a group may be outside the geographic coverage area 110 of base station 105, or otherwise unable to receive transmissions from base station 105. In some cases, multiple groups of UE 115 communicating via D2D communication can utilize a one-to-many (1:M) system, where each UE 115 transmits to every other UE 115 in the group. In some cases, base station 105 facilitates the scheduling of resources for D2D communication. In other cases, D2D communication is performed between UE 115s without involving base station 105.

[0072] Base station 105 can communicate with core network 130 and with each other. For example, base station 105 can interface with core network 130 via backhaul link 132 (e.g., via S1 or other interfaces). Base station 105 can communicate with each other directly (e.g., directly between base stations 105) or indirectly (e.g., via core network 130) on backhaul link 134 (e.g., via X2 or other interfaces).

[0073] Core network 130 can provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. Core network 130 may be an evolved packet core (EPC), which may include at least one Mobility Management Entity (MME), at least one Serving Gateway (S-GW), and at least one Packet Data Network (PDN) Gateway (P-GW). The MME can manage non-access stratum (e.g., control plane) functions, such as mobility, authentication, and bearer management for UE 115 served by base station 105 associated with the EPC. User IP packets can be transmitted via the S-GW, which itself may be connected to the P-GW. The P-GW can provide IP address allocation and other functions. The P-GW may be connected to network operator IP services. Operator IP services may include access to the Internet, intranets, IP Multimedia Subsystem (IMS), or packet-switched (PS) streaming services.

[0074] At least some of the network devices (e.g., base station 105) may include sub-components such as access network entities, which may be examples of access node controllers (ANCs). Each access network entity may communicate with UE 115 through multiple other access network transport entities (which may be referred to as radio headends, smart radio headends, or transmit / receive points (TRPs)). In some configurations, the various functions of each access network entity or base station 105 may be distributed across various network devices (e.g., radio headends and access network controllers) or incorporated into a single network device (e.g., base station 105).

[0075] Wireless communication system 100 can operate using one or more frequency bands (typically in the range of 300 MHz to 300 GHz). The region from 300 MHz to 3 GHz is often referred to as the Ultra High Frequency (UHF) region or decimeter band because the wavelength range extends from approximately one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features. However, the waves can be sufficiently permeable to penetrate structures for use in macrocells to provide service to UE 115 located indoors. Compared to the transmission of smaller frequencies and longer waves in the lower 300 MHz portion of the spectrum in the High Frequency (HF) or Very High Frequency (VHF) regions, UHF wave transmission can be associated with smaller antennas and shorter distances (e.g., less than 100 km).

[0076] The wireless communication system 100 can also operate in the ultra-high frequency (SHF) region using a frequency band from 3 GHz to 30 GHz (also known as the centimeter band). The SHF region includes frequency bands such as the 5 GHz industrial, scientific, and medical (ISM) band, which can be used opportunistically by devices capable of tolerating interference from other users.

[0077] The wireless communication system 100 can also operate in the extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz) (also referred to as the millimeter band). In some examples, the wireless communication system 100 can support millimeter-wave (mmW) communication between the UE 115 and the base station 105, and the EHF antennas of the corresponding device can be even smaller and more closely spaced compared to UHF antennas. In some cases, this can facilitate the use of antenna arrays within the UE 115. However, compared to SHF or UHF transmissions, EHF transmissions may suffer even greater atmospheric attenuation and shorter distances. The techniques disclosed herein can be employed across transmissions using one or more different frequency regions, and the designated use of frequency bands across these frequency regions can vary depending on the country or regulatory authority.

[0078] In some cases, wireless communication system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, wireless communication system 100 may employ Licensed Assisted Access (LAA), LTE Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed spectrum band (e.g., a 5 GHz ISM band). When operating in an unlicensed radio frequency spectrum band, wireless devices (e.g., base station 105 and UE 115) may employ a Listen-After-Speak (LBT) procedure before transmitting data to ensure that the frequency channel is idle. In some cases, operation in an unlicensed spectrum band may be based on a CA configuration combined with CC operation in a licensed spectrum band (e.g., LAA). Operation in the unlicensed spectrum may include downlink transmission, uplink transmission, peer-to-peer transmission, or a combination of these. Duplexing in the unlicensed spectrum may be based on Frequency Division Duplex (FDD), Time Division Duplex (TDD), or a combination of both.

[0079] In some examples, base station 105 or UE 115 may be equipped with multiple antennas, which can be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communication, or beamforming. For example, wireless communication system 100 may use a transmission scheme between a transmitting device (e.g., base station 105) and a receiving device (e.g., UE 115), wherein the transmitting device is equipped with multiple antennas, and the receiving device is equipped with one or more antennas. MIMO communication may employ multipath signal propagation to improve spectral efficiency by transmitting or receiving multiple signals via different spatial layers (this may be referred to as spatial multiplexing). For example, the transmitting device may transmit multiple signals via different antennas or different combinations of antennas. Similarly, the receiving device may receive multiple signals via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams. Different spatial layers may be associated with different antenna ports used for channel measurement and reporting. MIMO technology includes single-user MIMO (SU-MIMO) (where multiple spatial layers are sent to the same receiving device) and multi-user MIMO (MU-MIMO) (where multiple spatial layers are sent to multiple devices).

[0080] 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 or receiving device (e.g., base station 105 or UE 115) to form or guide an antenna beam (e.g., a transmit beam or a receive beam) along a spatial path between the transmitting and receiving devices. Beamforming can be achieved by combining signals transmitted via antenna elements of an antenna array such that signals propagating relative to a specific orientation of the antenna array experience constructive interference, while other signals experience destructive interference. Adjustments to the signals transmitted via the antenna elements can include applying certain amplitude and phase offsets to the signals carried by each antenna element in the antenna elements associated with the transmitting or receiving device. The adjustments associated with each antenna element can be defined by a set of beamforming weights associated with a specific orientation (e.g., relative to the antenna array of the transmitting or receiving device, or relative to some other orientation).

[0081] In one example, base station 105 may use multiple antennas or antenna arrays to perform beamforming operations for directional communication with UE 115. For example, base station 105 may transmit signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) multiple times in different directions, these signals may include signals transmitted according to different sets of beamforming weights associated with different transmission directions. Transmissions in different beam directions can be used (e.g., by base station 105 or receiving device (e.g., UE 115)) to identify the beam direction for subsequent transmissions and / or receptions performed by base station 105. Base station 105 may transmit signals (e.g., data signals associated with a specific receiving device) in a single beam direction (e.g., the direction associated with the receiving device (e.g., UE 115)). In some examples, the beam direction associated with transmissions along a single beam direction may be determined at least in part based on the signals transmitted in different beam directions. For example, UE 115 may receive one or more signals transmitted by base station 105 in different directions, and UE 115 may report to base station 105 an indication of the signal it received that has the highest signal quality or otherwise acceptable signal quality. Although these techniques are described with reference to signals transmitted by base station 105 in one or more directions, UE 115 may employ similar techniques to transmit signals multiple times in different directions (e.g., to identify beam directions for subsequent transmissions or receptions by UE 115) or to transmit signals in a single direction (e.g., to transmit data to a receiving device).

[0082] When receiving various signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) from base station 105, a receiving device (e.g., UE 115, which may be an example of an mmW receiving device) can attempt multiple receive beams. For example, the receiving device can attempt multiple receive directions by receiving via different antenna subarrays, by processing the received signals according to different antenna subarrays, by receiving according to different sets of receive beamforming weights applied to the signals received at multiple antenna elements of the antenna array, or by processing the received signals according to different sets of receive beamforming weights applied to the signals received at multiple antenna elements of the antenna array (any of the above operations can be referred to as “listening” according to different receive beams or receive directions). In some examples, the receiving device can use a single receive beam to receive along a single beam direction (e.g., when receiving data signals). A single receiving beam can be aligned on a beam direction determined at least in part based on listening to different receiving beam directions (e.g., a beam direction determined at least in part based on listening to multiple beam directions to have the highest signal strength, highest signal-to-noise ratio, or otherwise acceptable signal quality).

[0083] In some cases, the antennas of base station 105 or UE 115 may be located within one or more antenna arrays that can support MIMO operation or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some cases, the antennas or antenna arrays associated with base station 105 may be located in different geographical locations. Base station 105 may have antenna arrays with multiple rows and columns of antenna ports that base station 105 can use to support beamforming for communication with UE 115. Similarly, UE 115 may have one or more antenna arrays that can support various MIMO or beamforming operations.

[0084] In some cases, the wireless communication system 100 may be a packet-based network operating according to a layered protocol stack. In the user plane, communication at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. In some cases, the Radio Link Control (RLC) layer may perform packet fragmentation and reassembly for communication on logical channels. The MAC layer may perform priority handling and multiplexing of logical channels to transport channels. The MAC layer may also use Hybrid Automatic Repeat Request (HARQ) to provide retransmissions at the MAC layer to improve link efficiency. In the control plane, the RRC protocol layer may provide the establishment, configuration, and maintenance of RRC connections (which support radio bearers for user plane data) between the UE 115 and the base station 105 or core network 130. At the physical (PHY) layer, transport channels may be mapped to physical channels.

[0085] In some cases, UE 115 and base station 105 can support data retransmission to increase the likelihood of successful data reception. HARQ feedback is a technique to increase the likelihood of correct data reception on communication link 125. HARQ may 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 throughput at the MAC layer under poor radio conditions (e.g., signal and noise conditions). In some cases, the radio device can support same-slot HARQ feedback, where the device can provide HARQ feedback for data received in a previous symbol within a specific time slot. In other cases, the device can provide HARQ feedback in subsequent time slots or according to some other time interval.

[0086] It can be in the basic unit of time (which can, for example, refer to T) s The time interval in LTE or NR is represented as a multiple of a sampling period of 1 / 30,720,000 seconds. The time interval of communication resources can be organized according to radio frames, each with a duration of 10 milliseconds (ms), where the frame period can be expressed as T. f =307,200T sRadio frames can be identified by System Frame Numbers (SFNs) ranging from 0 to 1023. Each frame may include 10 subframes numbered from 0 to 9, and each subframe may have a duration of 1 ms. Subframes may be further divided into two time slots, each with a duration of 0.5 ms, and each time slot may contain 6 or 7 modulation symbol periods (e.g., depending on the length of the cyclic prefix added before each symbol period). Excluding the cyclic prefix, each symbol period may contain 2048 sampling periods. In some cases, a subframe may be the minimum scheduling unit of the wireless communication system 100 and may be referred to as a Transmission Time Interval (TTI). In other cases, the minimum scheduling unit of the wireless communication system 100 may be shorter than a subframe or may be dynamically selected (e.g., in a burst of shortened TTIs (sTTIs) or in selected component carriers using sTTIs).

[0087] In some wireless communication systems, time slots can be further divided into multiple micro-time slots containing one or more symbols. In some instances, the symbol or micro-time slot of a micro-time slot can be the smallest scheduling unit. The duration of each symbol can vary according to, for example, the SCS or the frequency band of operation. Furthermore, some wireless communication systems can implement time slot aggregation, where multiple time slots or micro-time slots are aggregated together and used for communication between UE 115 and base station 105.

[0088] The term "carrier" refers to a set of radio frequency spectrum resources having a defined physical layer structure for supporting communication on communication link 125. For example, a carrier of communication link 125 may include a portion of the radio frequency spectrum band that operates according to physical layer channels for a given radio access technology. Each physical layer channel may carry user data, control information, or other signaling. Carriers may be associated with predefined frequency channels (e.g., E-UTRA Absolute Radio Channel Number (EARFCN)) and may be positioned according to a channel grid for discovery by UE 115. A carrier may be downlink or uplink (e.g., in FDD mode), or may be configured to carry both downlink and uplink communication (e.g., in TDD mode). In some examples, the signal waveform transmitted on a carrier may consist of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques such as OFDM or DFT-s-OFDM).

[0089] The carrier organization structure can vary depending on the radio access technology (e.g., LTE, LTE-A, NR, etc.). For example, communication on a carrier can be organized according to a Time Interval (TTI) or time slot, each of which can include user data and control information or signaling to support the decoding of the user data. A carrier can also include dedicated acquisition signaling (e.g., synchronization signals or system information) and control signaling to coordinate operations on the carrier. In some examples (e.g., in a CA configuration), a carrier can also have acquisition signaling or control signaling to coordinate operations on other carriers.

[0090] Physical channels can be multiplexed on a carrier using various techniques. For example, time division multiplexing (TDM), frequency division multiplexing (FDM), or hybrid TDM-FDM techniques can be used to multiplex physical control channels and physical data channels on a downlink carrier. In some examples, control information transmitted in the physical control channel can be distributed in a concatenated manner between different control regions (e.g., between a common control region or common search space and one or more UE-specific control regions or UE-specific search spaces).

[0091] 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 carrier or the “system bandwidth” of the wireless communication system 100. For example, the carrier bandwidth can be one of several predetermined bandwidths for a carrier specific to a wireless access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz). In some examples, each served UE 115 can be configured to operate on a portion or all of the carrier bandwidth. In other examples, some UEs 115 can be configured to operate using a narrowband protocol type associated with a predefined portion or range within the carrier (e.g., a set of subcarriers or RBs) (e.g., “in-band” deployment of a narrowband protocol type).

[0092] In systems employing MCM technology, a resource element may include a symbol period (e.g., the duration of a modulation symbol) and a subcarrier, where the symbol period and 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). Therefore, the more resource elements UE 115 receives and the higher the order of the modulation scheme, the higher the data rate can be for UE 115. In MIMO systems, wireless communication resources can refer to a combination of radio frequency spectrum resources, temporal resources, and spatial resources (e.g., spatial layers), and the use of multiple spatial layers can further increase the data rate used for communication with UE 115.

[0093] The devices of the wireless communication system 100 (e.g., base station 105 or UE 115) may have a hardware configuration that supports communication on a specific carrier bandwidth, or may be configurable to support communication on one carrier bandwidth in a set of carrier bandwidths. In some examples, the wireless communication system 100 may include base station 105 and / or UE 115, which are capable of supporting simultaneous communication via carriers associated with more than one different carrier bandwidth.

[0094] The wireless communication system 100 can support communication with the UE 115 on multiple cells or carriers (a feature that may be referred to as CA or multi-carrier operation). Depending on the CA configuration, the UE 115 can be configured with multiple downlink CCs and one or more uplink CCs. CA can be used in conjunction with both FDD and TDD component carriers.

[0095] In some cases, the wireless communication system 100 may utilize enhanced component carriers (eCC). eCC can be characterized by one or more features including: a wider carrier or frequency channel bandwidth, a shorter symbol duration, a shorter TTI duration, or a modified control channel configuration. In some cases, eCC may be associated with a CA configuration or a dual connectivity configuration (e.g., when multiple serving cells have suboptimal or non-ideal backhaul links). eCC can also be configured for use in unlicensed spectrum or shared spectrum (e.g., where more than one operator is permitted to use the spectrum). eCC characterized by a wide carrier bandwidth may include one or more segments that can be used by a UE 115 that cannot monitor the entire carrier bandwidth or is otherwise configured to use a limited carrier bandwidth (e.g., to save power).

[0096] In some cases, eCC can utilize a different symbol duration than other CCs, which may include using a reduced symbol duration compared to other CCs. A shorter symbol duration can be associated with increased spacing between adjacent subcarriers (e.g., increased SCS). Devices utilizing eCC (e.g., UE 115 or base station 105) can transmit wideband signals (e.g., based on frequency channels or carrier bandwidths of 20, 40, 60, 80 MHz, etc.) with a reduced symbol duration (e.g., 16.67 microseconds). The TTI in eCC can include one or more symbol periods. In some cases, the TTI duration (i.e., the number of symbol periods in the TTI) can be variable.

[0097] In addition, wireless communication systems (such as NR systems) can utilize any combination of licensed, shared, and unlicensed spectrum bands. The flexibility in eCC symbol duration and subcarrier spacing allows for the use of eCC across multiple spectrums. In some examples, NR spectrum sharing can improve spectrum utilization and efficiency, especially through dynamic vertical (e.g., across frequency) and horizontal (e.g., across time) sharing of resources.

[0098] As noted above, one or more of base stations 105 may provide low-frequency band connectivity (e.g., connectivity via one or more low-frequency band carriers), and one or more of base stations 105 may provide high-frequency band connectivity (e.g., connectivity via one or more high-frequency band carriers). Furthermore, in some cases, carriers provided by different base stations 105 or at different frequencies (e.g., in different frequency bands) may not be time-synchronized, and UE 115 may measure the timing difference between the two carriers and provide an indication of the timing difference to one or more base stations 105. The base station 105 receiving the indication of the timing difference may determine, at least in part, that UE 115 will use asynchronous CA to communicate on the carriers (e.g., using a high-frequency band carrier as an aggregation carrier and a low-frequency band carrier as an anchor carrier), and configure UE 115 to use asynchronous CA, at least in part, by configuring UE 115 to observe the reporting delay between receiving packets on the aggregation carrier and sending acknowledgments of packets on the anchor carrier.

[0099] Figure 2 Examples of a wireless communication system 200 supporting asynchronous CA according to various aspects of this disclosure are shown. In some examples, the wireless communication system 200 may be implemented by aspects of the wireless communication system 100. Figure 2 In the example, the wireless communication system 200 may include a first base station 105-a, a second base station 105-b, a third base station 105-c, and a fourth base station 105-d, which may be Figure 1 An example of base station 105. The wireless communication system 200 may also include a first UE 115-a, a second UE 115-b, and a third UE 115-c, which may be... Figure 1 Example of UE 115.

[0100] In this example, the first base station 105-a may have a relatively large first geographical coverage area 205 and can support transmission at relatively low frequencies. For example, the first base station 105-a can support low-frequency band transmission to multiple UEs 115. The second base station 105-b may have a relatively small second geographical coverage area 210 and can support transmission at relatively high frequencies. Similarly, the third base station 105-c may have a relatively small third geographical coverage area 215, and the fourth base station 105-d may have a relatively small fourth geographical coverage area 220, and each of the third and fourth base stations 105-c and 105-d can support transmission at relatively high frequencies.

[0101] In this example, the first UE 115-a may have a first connection, which may be a connection to the first base station 105-a and may include low-frequency band transmission 240. Similarly, the second UE 115-b may have a first connection, which may be a connection to the first base station 105-a and may include low-frequency band transmission 245. Likewise, the third UE 115-c may have a first connection, which may be a connection to the first base station 105-a and may include low-frequency band transmission 250.

[0102] The first UE 115-a can be within the range of the high-frequency band transmission 225 from the second base station 105-b and monitor the high-frequency band transmission 225. Similarly, the second UE 115-b can be within the range of the high-frequency band transmission 230 from the third base station 105-c and monitor the high-frequency band transmission 230. Likewise, the third UE 115-c can be within the range of the high-frequency band transmission 235 from the fourth base station 105-d.

[0103] As noted above, high-frequency band transmissions 225, 230, and 235 can use relatively high frequencies. In some cases, high-frequency band transmissions 225, 230, and 235 can use frequencies in the 4 GHz or higher range. In some examples, high-frequency band transmissions 225, 230, and 235 can use mmW frequencies and can be beamformed mmW transmissions. Low-frequency band transmissions 240–250 can use relatively low frequencies, such as frequencies in the 600 MHz region. In some cases, low-frequency band transmissions 240, 245, and 250 can support anchor carrier connections, and high-frequency band transmissions 225, 230, and 235 can support one or more CCs or eCCs aggregated with anchor connections. In some cases, the first base station 105-a can be operated by a mobile network operator (MNO), and the second base station 105-b, the third base station 105-c, and the fourth base station 105-d can be operated by different MNOs or non-MNO base station 105. Furthermore, low-frequency transmissions 240, 245, and 250 can utilize licensed spectrum, while high-frequency transmissions 225, 230, and 235 can utilize unlicensed spectrum, and vice versa.

[0104] In this example, the first base station 105-a can provide umbrella-style low-band connectivity for each of the high-frequency base stations 105-b, 105-c, and 105-d. Due to attenuation and directional transmission of the high-frequency base stations 105-b, 105-c, and 105-d, each of these base stations 105 may be unable to detect high-frequency band communication from the other base stations 105, and in some cases, this may be in an indoor deployment of a non-MNO base station 105. Furthermore, similar to what has been noted above, the high-frequency base stations 105-b, 105-c, and 105-d may not have sufficient reliability or latency to support backhaul connections for timing synchronization between base stations 105 (e.g., the backhaul connection may not have predictable, sufficient latency to support network time synchronization protocols such as IEEE 1588).

[0105] High-frequency band transmissions 225, 230, and 235 may not be time-synchronized with each other or with low-frequency band transmissions 240, 245, and 250. For example, high-frequency band transmission 225 may not be time-synchronized with low-frequency band transmission 240. The first UE 115-a may have at least a first connection established with the first base station 105-a using a first carrier including low-frequency band transmission 240, and may also monitor one or more of the high-frequency band transmissions 225. In some cases, the first base station 105-a may configure the first UE 115-a to monitor one or more of the high-frequency band transmissions 225. The first UE 115-a may measure the timing difference between the high-frequency band transmission 225 and the low-frequency band transmission 240. In such a scenario, the first UE 115-a may include a common oscillator or other common timing reference (e.g., a crystal timing reference, a resonator, etc.), which UE 115-a can use to measure the timing difference between the high-frequency band transmission 225 and the low-frequency band transmission 240. In some cases, the first UE 115-a can derive the low-frequency and high-frequency band clocks based on the common timing reference and can monitor one or more reference signals (e.g., a discovery reference signal (DRS) or a synchronization signal such as a primary synchronization signal (PSS) or a secondary synchronization signal (SSS)) from both the first base station 105-a and the second base station 105-b (and also monitor reference signals detectable by the first UE 115-a from any other base station 105, such as the third base station 105-c). In some cases, the first UE 115-a can derive the timing difference between the low-frequency band transmission 240 and the high-frequency band transmission 225 based on the sampling rate associated with the high-frequency band transmission 225. The timing difference may include timing offsets between the following: reference subframe, time slot, symbol, sample, or any combination of these items or other timing or scheduling units included in a carrier of low-frequency transmission 240 and another carrier of high-frequency transmission 225.

[0106] The first UE 115-a can send an indication of the measured timing difference to a base station (such as the first base station 105-a or the second base station 105-b). For example, the first UE 115-a can send the indication of the timing difference as part of a carrier report. In some cases, a report of the measurement with timing difference can be sent via a MAC control element (MAC-CE) based on a report or an RRC measurement report.

[0107] In some cases, the first UE 115-a may monitor high-frequency band transmission 225 before establishing a low-frequency band connection with the first base station 105-a. For example, the first UE 115-a may monitor high-frequency band transmission on an opportunistic or periodic basis. In some cases, after the first UE 115-a has established a low-frequency band connection with the first base station 105-a using low-frequency band transmission 240, the first base station 105-a may configure the first UE 115-a to monitor high-frequency band transmission 225, for example, on a periodic or other scheduling basis, on an opportunistic basis, on an event-triggered basis, or on an indication basis. Monitoring high-frequency band transmission may include monitoring one or more reference signals (e.g., DRS, SSS, PSS) or other signals carried via high-frequency band transmission.

[0108] A base station 105 (e.g., a first base station 105-a or a second base station 105-b) receiving an indication of timing difference can determine the connection mode that the first UE 115-a will use for communication using high-frequency band transmission 225. For example, based at least in part on the timing difference, base station 105 can determine that the first UE 115-a will use a dual-connection mode (e.g., having separate radio connections for downlink and uplink data and control signaling via high-frequency band transmission 225), a synchronous CA mode (e.g., using an anchor carrier including low-frequency band transmission 240 and an aggregated carrier including high-frequency band transmission 225, with uplink control signaling associated with the aggregated carrier via the anchor carrier according to synchronous CA technology), or an asynchronous CA mode (e.g., using an anchor carrier including low-frequency band transmission 240 and an aggregated carrier including high-frequency band transmission 225, with uplink control signaling associated with the aggregated carrier via the anchor carrier according to asynchronous CA technology as provided herein).

[0109] Base station 105 can determine, at least in part, that the first UE 115-a will use asynchronous CA based on comparing the timing difference with a threshold time difference. For example, base station 105 can compare the timing difference with a threshold time difference, and if the timing difference is greater than the threshold time difference, it can determine that the first UE 115-a will use an asynchronous connection mode, such as dual connection or asynchronous CA; alternatively, if the timing difference is less than the threshold time difference, base station 105 can determine that the first UE 115-a will use synchronous CA. Base station 105 can determine the threshold time difference, at least in part, based on the SCS and other timing characteristics of low-band transmission 240 and high-band transmission 225. Base station 105 can also evaluate other factors to determine the connection mode for communication using high-band transmission 225 that the first UE 115-a will use.

[0110] For example, base station 105 can also determine, at least in part, that the first UE 115-a will use asynchronous CA based on the frequency difference between low-frequency transmission 240 and high-frequency transmission 225. In some cases, if there is a relatively small frequency difference between the carriers using low-frequency transmission 240 and high-frequency transmission 225 (e.g., low-frequency transmission 240 and high-frequency transmission 225 are actually part of the same frequency band), base station 105 can determine that the first UE 115-a will use synchronous CA. Similarly, if the frequency difference exceeds a threshold frequency difference, base station 105 can determine that the first UE 115-a will use asynchronous CA. If base station 105 is able to detect high-frequency transmission 225, base station 105 can determine the frequency difference between low-frequency transmission 240 and high-frequency transmission 225, or the first UE 115-a can send an indication of the frequency difference to base station 105.

[0111] As another example, base station 105 may also determine, at least in part, that the first UE 115-a will use asynchronous CA based on whether the first UE 115-a is able to establish an uplink connection on the carrier using high-frequency band transmission 225. In some cases, if the first UE 115-a is unable to establish an uplink connection on the carrier using high-frequency band transmission 225, base station 105 may determine that the first UE 115-a will use CA, such as asynchronous CA or synchronous CA.

[0112] In some cases, the first UE-115-a may determine channel quality metrics, such as Received Signal Strength Indicator (RSSI), Reference Received Power (RSRP), Reference Received Quality (RSRQ), CSI, Channel Quality Indicator (CQI), Precoding Matrix Indicator (PMI), Precoding Type Indicator (PTI), Rank Indicator (RI) (which may also be referred to as Rank 1 CQI), Signal-to-Noise Ratio (SNR), Signal-to-Interference Plus Noise Ratio (SINR), or any combination thereof, and send an indication of the channel quality metric to base station 105. Base station 105 may compare the measured channel quality metric with a threshold value for the channel quality metric and determine, at least in part, whether the first UE 115-a can establish an uplink connection on the carrier using high-frequency band transmission 225 based on the comparison. In some examples, the threshold value for the channel quality metric may depend at least in part on the power level of the first UE 115-a.

[0113] The first UE 115-a may also send an indication to the base station 105 regarding whether the first UE 115-a can establish an uplink connection on the carrier using the high-frequency band transmission 225. For example, the first UE 115-a may send an indication to the base station 105 regarding the following: the first UE 115-a cannot establish an uplink connection on the carrier using the high-frequency band transmission 225 because the uplink connection using the high-frequency band transmission 225 may exceed the maximum allowable illumination (MPE) constraint, or because the battery charge level of the first UE 115-a may be insufficient to support the uplink connection using the high-frequency band transmission 225. As another example, the first UE 115-a may attempt to establish an uplink connection with the second base station 105-b using the high-frequency band transmission 225 via one or more random access procedures, and if one or more random access procedures are unsuccessful, the first UE 115-a may send an indication to the base station 105 regarding the inability of the first UE 115-a to establish an uplink connection on the carrier using the high-frequency band transmission 225. For one or more random access procedures, the first UE 115-a may utilize full transmit power or the transmit power specified by the base station 105. In some cases, in deployments where reciprocity between downlink and uplink transmissions using high-frequency band transmission 225 may not be assumed (e.g., deployments using different transmit and receive arrays or FDD), the first UE 115-a may attempt to establish an uplink connection with the second base station 105-b via one or more random access procedures using high-frequency band transmission 225.

[0114] As another example, base station 105 may also determine, at least in part, that the first UE 115-a will use asynchronous CA based on whether aggregation between carriers supported by the first base station 105-a and the second base station 105-b can be performed. For example, base station 105 may assess whether the backhaul connection between the first base station 105-a and the second base station 105-b has sufficient quality (e.g., tolerable latency) or reliability to support CA. As another example, base station 105 may determine whether the first base station 105-a and the second base station 105-b are operated by the same MNO or by different MNOs with protocols that allow aggregation. In some cases, if carriers supported by the first base station 105-a and the second base station 105-b can be aggregated, base station 105 may determine that the first UE 115-a will use CA, such as asynchronous CA or synchronous CA.

[0115] If base station 105 determines that the first UE 115-a will use asynchronous CA mode, base station 105 may configure the first UE 115-a to observe at least a minimum delay between receiving downlink transmissions via high-frequency band transmission 225 and transmitting related uplink transmissions via low-frequency band transmission 240. For example, base station 105 may configure the first UE 115-a to observe at least a minimum reporting delay between receiving packets via high-frequency band transmission 225 and transmitting packet acknowledgments via low-frequency band transmission 240. An acknowledgment may be an indication of successful packet decoding (referred to herein as ACK) or an indication of unsuccessful packet decoding (referred to herein as NACK). As another example, base station 105 may configure the first UE 115-a to observe at least a minimum reporting delay between receiving packets via high-frequency band transmission 225 and transmitting channel quality metrics (such as CSI or other relevant information, such as beam management information, rate control information, cross-carrier control information, power control information, radio resource management information, buffer status information, etc.) corresponding to the packets via low-frequency band transmission 240. The following explains further details regarding the timing of uplink transmissions performed by UE 115 operating in asynchronous CA communication mode. Furthermore, in the descriptions of the first UE 115-a, the first base station 105-a, and the second base station 105-b, it should be understood that other UEs 115 and base stations 105 can utilize similar techniques.

[0116] Figure 3 Examples of timing difference measurement 300 supporting asynchronous CA according to various aspects of this disclosure are shown. In some examples, timing difference measurement 300 may be used in various aspects of wireless communication system 100 or 200 to determine whether UE 115 will use asynchronous CA, and if so, to determine the minimum amount of delay that UE 115 will use in uplink signaling via anchor carrier.

[0117] In this example, the first base station 105-d can transmit using frequency band 305, the second base station 105-e can transmit using frequency band 310, and the third base station 105-f can transmit using frequency band 315. In this example, the first base station 105-d can transmit at UE 115 (e.g., Figure 1 or Figure 2 Both low-frequency band transmission 320 and high-frequency band transmission 325 are received at UE 115. The second base station 105-e can transmit high-frequency band transmission 330 that can be received at UE 115, and the third base station 105-f can transmit high-frequency band transmission 335 that can be received at UE 115.

[0118] In this example, the first base station 105-d can initiate a transmission starting at t0, where t0 can be the start time of a subframe, time slot, symbol, symbol sampling, or some other timing or scheduling unit. The UE 115 can have a connection established with the first base station 105-d for low-band transmission 320, and can also be within the coverage areas of the second base station 105-e and the third base station 105-f, enabling the UE 115 to detect and monitor high-band transmissions 330 and 335. In some cases, the UE 115 can measure the time difference between transmissions associated with different base stations 105 from which the UE 115 can detect transmissions (e.g., base stations 105 from which the UE 115 can detect DRS, PSS, SSS, or other reference or synchronization signals).

[0119] In this example, the high-frequency band transmissions 330 and 335 of the second base station 105-e and the third base station 105-f may be out of sync with the first base station 105-d (e.g., due to oscillator drift, due to only being roughly synchronized using low-frequency band timing, or due to some other reason), such that the high-frequency band transmission 330 of the second base station 105-e begins at a first time difference (ΔT1 340) relative to the transmissions 320 and 325 of the first base station 105-d, and the high-frequency band transmission 335 of the third base station 105-f begins at a second time difference (ΔT2 345) relative to the transmissions 320 and 325 of the first base station 105-d.

[0120] The UE 115, capable of detecting the high-frequency band transmission 330 of the second base station 105-e and the high-frequency band transmission 335 of the third base station 105-f, can measure the corresponding timing differences 340, 345. In some cases, the UE 115 can derive the timing difference using a common timing reference such as a common oscillator. Such a UE 115 can measure a first timing difference 340, a second timing difference 345, or both, and can send an indication of the time difference to one or more base stations 105. The UE 115 can measure the timing difference according to the sampling rate used for one of the transmission bands such as high-frequency band transmission 330 or high-frequency band transmission 335. Furthermore, the UE 115 or the base station 105 can convert the timing difference measured according to the sampling rate into a timing difference expressed in time units (e.g., milliseconds or microseconds).

[0121] Base station 105 can receive an indication of timing difference and determine, at least in part, whether UE 115 will use asynchronous CA as described herein based on the timing difference. For example, the first base station 105-d can receive timing difference 340 and determine whether UE 115 intends to use asynchronous CA for communication using high-frequency band transmission 330, or it can receive timing difference 345 and determine whether UE 115 intends to use asynchronous CA for communication using high-frequency band transmission 335.

[0122] Figure 4 Examples of minimum reporting latency 400 supporting asynchronous CA according to various aspects of this disclosure are shown. In some examples, minimum reporting latency 400 may implement various aspects of wireless communication system 100 or 200.

[0123] In the example with a minimum reporting delay of 400, UE 115 can use a first carrier supported by base station 105 to establish a connection with base station 105. The first carrier can be a relatively low-frequency carrier and can include a low-frequency band time slot (LB time slot) 405.

[0124] The UE can also detect and monitor carriers in a relatively high-frequency band supported by another base station 105. The carrier in the relatively high-frequency band may include a high-frequency band (HB) time slot 410. The carrier used for HB time slot 410 may have a different SCS and a different time slot duration compared to the carrier used for LB time slot 405. For example, the carrier used for LB time slot 405 may have a lower SCS than the carrier used for HB time slot 410, and LB time slot 405 may have a longer duration than HB time slot 410. In some cases, the low-frequency band carrier may have an SCS of 30 kHz, while the high-frequency band carrier may have an SCS of 60 kHz.

[0125] As described herein, in some cases, UE 115 may use a common oscillator (or other common timing reference) to derive a timing difference 425 between low-frequency time slot 405 and high-frequency time slot 410. While the minimum reporting delay 400 is presented as a timing offset between time slots, it should be understood that the timing difference may be a timing offset between other timing or scheduling units of the two carriers. In some cases, UE 115 or base station 105 may convert a timing difference measured or indicated according to other timing or scheduling units into a timing offset between time slots based on information about the two carriers (e.g., frequency, SCS, number of symbols per time slot or subframe, number of samples per symbol, etc.).

[0126] UE 115 may send an indication of timing difference to serving base station 105 (e.g., base station 105 supporting LB time slot 405 or base station 105 supporting HB time slot 410). UE 115 may also send indications to serving base station 105 of other characteristics of the carrier used for LB time slot 405 and HB time slot 410. For example, UE 115 may determine and send to serving base station 105: an indication of the frequency and SCS used for the carrier, an indication of the channel quality of the carrier, the duration of the time slot used for the carrier, the duration of the uplink or downlink portion of the time slot used for the carrier, or the duration of the guard period used for the carrier. UE 115 may also determine and send to serving base station 105 an indication of uplink timing advance used for the carrier, which may indicate the length of time required for uplink transmission from UE 115 using the carrier to reach base station 105 supporting the carrier. UE 115 can also determine and transmit an indication of the processing time for packets received via a carrier (e.g., the amount of time required for UE 115 to decode packets) to the serving base station 105. In some cases, UE 115 may measure at least one of the uplink timing advance for the first carrier, the processing time for packets, or the duration of the second timeslot for the second carrier, and transmit an indication of at least one of the uplink timing advance, processing time, or duration of the second timeslot for the second carrier to the base station. The serving base station 105 may use this information from UE 115 and other criteria described herein to determine whether UE 115 uses asynchronous CA for two or more carriers, and if so, configure UE 115 to observe at least a minimum delay in uplink signaling via the anchor carrier.

[0127] For example, in the example of minimum reporting delay 400, the serving base station 105 can configure UE 115 to use LB slot 405 as an anchor carrier in asynchronous CA operation mode. The serving base station 105 can also configure UE 115 to observe at least a minimum delay between receiving data in HB slot 410 and performing related uplink signaling (e.g., uplink control signaling) in LB slot 405. If HB slot 410 does not have at least a minimum delay before the uplink portion of LB slot 405, UE 115 can wait until the uplink portion of subsequent LB slot 405 to perform uplink signaling related to the data received in HB slot 410.

[0128] In some cases, the serving base station 105 can configure the UE 115 to observe the minimum delay by configuring the reporting parameter associated with HB slot 410 (which may be referred to herein as K1). For example, in the example of minimum reporting delay 400, K1 is zero for HB slots 0, HB slot 2, and HB slot 4, and as indicated by the arrow, the UE 115 performs the associated uplink signaling in the immediate subsequent uplink portion of LB slot 405. However, for HB slots 1 and HB slot 3, K1 is 1, and the UE 115 observes the delay period before performing the associated uplink signaling in the uplink portion of LB slot 405 immediately following the delay period.

[0129] In some cases, the serving base station 105 can determine the delay period according to the following delay equation, where the following variables represent the following physical quantities:

[0130] • T_async represents the timing difference, such as the time offset between reference LB time slot 405 and reference HB time slot 410;

[0131] • T_slot_CC1 represents the duration of LB slot 405;

[0132] • T_slot_CC2 represents the duration of HB slot 410;

[0133] • T_UL_CC1 represents the duration of the uplink portion of LB slot 405;

[0134] • T_UL_TA_CC1 indicates that the uplink timing of the carrier in LB slot 405 is advanced; and

[0135] T_proc_CC2 represents the processing time used by UE 115 to decode packets received by UE 115 on the carrier in HB slot 410.

[0136]

[0137] Serving base station 105 can also configure K1 using a rounding function. For example, serving base station 105 can configure K1 to be equal to the rounded value of (delay), and UE 115 can be configured to observe the number of delay periods indicated by the value of K1 between receiving data via HB slot 410 and performing associated uplink signaling via LB slot 405 (e.g., zero delay periods if K1 = 0, one delay period if K1 = 1, two delay periods if K1 = 2, and so on). Therefore, UE 115 can observe the minimum delay (e.g., the number of delay periods indicated by the value of K1), and then perform uplink signaling in the subsequent uplink portion immediately following LB slot 405.

[0138] In some cases, if the minimum delay is large (e.g., due to a large timing difference or a large packet processing time), the serving base station 105 can configure the UE 115 to observe the minimum delay at least in part via the RRC protocol. For example, the serving base station 105 can configure a certain amount of delay for the carrier via the RRC protocol and then configure only the additional amount of delay via the K1 value. The UE 115 can determine the minimum delay to be observed by combining the delay configured by the RRC with the delay signaled by K1, thereby reducing the number of bits required for signaling associated with K1.

[0139] In some cases, the serving base station 105 may configure the UE 115 to observe at least a minimum delay between receiving packets in HB slot 410 and reporting acknowledgments (e.g., ACK or NACK) in LB slot 405. The serving base station 105 may configure the UE 115 to report acknowledgments as part of the Physical Uplink Shared Channel (PUSCH) or Physical Uplink Control Channel (PUCCH) within LB slot 405.

[0140] The serving base station 105 can similarly configure the UE 115 to observe at least a minimum delay between receiving packets in HB slot 410 and reporting relevant information (such as one or more channel quality metrics (e.g., CSI or other relevant information), beam management information, rate control information, cross-carrier control information, power control information, radio resource management information, buffer status information, etc.) in LB slot 405. The serving base station 105 can configure different minimum delays (e.g., different K1 values) for different parameters to be reported by the UE 115. For example, in some cases, the serving base station 105 can replace T_proc_CC2 in the above delay equation with the amount of time required to determine a specific type of information to be reported by the UE 115, such as the amount of time required to determine CSI. Similarly, in some cases, the serving base station 105 can replace T_slot_CC2 in the above delay equation with the duration specific to a specific type of information to be reported by the UE 115, such as the duration of a portion of HB slot 410 including a CSI reference signal (CSI-RS) or CSI interference measurement (CSI-IM).

[0141] In some examples, HB slot 410 may include both uplink and downlink portions, and the serving base station 105 may replace T_slot_CC2 in the above delay equation with a duration corresponding only to the downlink portion of HB slot 410. Furthermore, in some examples, T_UL_CC1 may vary between LB slots 405 depending on how much uplink data is scheduled for a given LB slot 405. For example, if ACK / NACK is the only uplink data scheduled for LB slot 405, then T_UL_CC1 may be the duration of a single symbol.

[0142] Figure 5 Examples of a minimum reporting delay 500 supporting asynchronous CA according to various aspects of this disclosure are shown. In some examples, the minimum reporting delay 500 may be implemented by aspects of wireless communication systems 100 or 200.

[0143] In the example with a minimum reporting delay of 500, UE 115 can use a first carrier supported by base station 105 to establish a connection with base station 105. The first carrier can be a relatively low-frequency carrier and can include LB time slot 505. UE 115 can also detect and monitor a relatively high-frequency carrier supported by another base station 105. The relatively high-frequency carrier can include HB time slot 510. In some cases, the low-frequency carrier can have an SCS of 30 kHz, while the high-frequency carrier can have an SCS of 480 kHz. HB time slot 510 can be offset relative to LB time slot 505 by a timing difference of 525.

[0144] Using the techniques described above with reference to minimum reporting delay 400, the serving base station 105 (e.g., base station 105 supporting LB time slot 505 or base station 105 supporting HB time slot 510) can configure UE 115 to observe at least a minimum delay between receiving data in HB time slot 510 and performing associated uplink signaling (e.g., uplink control signaling) in LB time slot 505. However, in minimum reporting delay 500, the SCS difference between HB time slot 510 and LB time slot 505 is much larger than the SCS difference between HB time slot 410 and LB time slot 405 in minimum reporting delay 400. In minimum reporting delay 500, the serving base station 105 can configure multiple consecutive HB time slots 510 to have the same K1 value, and uplink signaling associated with multiple consecutive HB time slots 510 having the same K1 value can occur in the same subsequent portion of LB time slot 505.

[0145] Figure 6 Examples of a process flow 600 supporting asynchronous CA according to various aspects of this disclosure are shown. In some examples, process flow 600 may be implemented by aspects of wireless communication systems 100 or 200.

[0146] Process flow 600 may include a first base station 105-g and a second base station 105-h (which may be respectively) Figure 1 , 2 Or an example of base station 105 (or 3) and UE 115-d (which may be) Figure 1 This refers to the transmission between high-frequency band and low-frequency band transmissions between UE 115 (or UE 115 in example 2). Initially, the first base station 105-g and UE 115-d can establish a low-frequency band connection 605. Such a connection can be established using conventional connection establishment techniques. In some cases, the low-frequency band connection 605 can be a low-frequency band anchor carrier connection.

[0147] At 610, the first base station 105-g can be configured to report carrier information for one or more UEs, such that the first base station 105-g can receive reports including indications of carrier characteristics (e.g., timing differences between transmissions supported by the first base station 105-g and transmissions of other base stations 105 (such as the second base station 105-h)) and other carrier-related information (e.g., information about the UE's ability to establish an uplink connection on the carrier). The first base station 105-g can send configuration information 615 related to carrier reporting to the UE 115-d. In some cases, the configuration information 615 can be sent in control signaling such as RRC signaling (e.g., downlink control information).

[0148] At 620, UE 115-d can identify the carrier reporting configuration used to report carrier-related information to the first base station 105-g. In some cases, UE 115-d can identify the carrier reporting configuration based on configuration information 615 received from the first base station 105-g. In some cases, UE 115-d can be configured to detect and measure the timing difference between transmissions of two or more base stations 105, and report the measured timing difference to the serving base station 105.

[0149] The first base station 105-g can use the established low-frequency band connection to send downlink low-frequency band transmission 625 to the UE 115-d. The downlink low-frequency band transmission 625 may have timing established during the connection establishment of the low-frequency band connection. The first base station 105-g may also optionally establish a high-frequency band connection with the UE 115-d and send high-frequency band transmission 630.

[0150] Based on the identified carrier reporting configuration, UE 115-d can monitor one or more high-frequency band transmissions (e.g., reference signals transmitted using high-frequency band carriers) of one or more other base stations 105. Figure 4 In the example, UE 115-d can be located such that UE 115-d can detect high-frequency band transmission 635 performed by the second base station 105-h. In some cases, UE 115-d can also detect other high-frequency band transmissions from other base stations 105. Furthermore, in some cases, the first base station 105-g can configure one or more UEs 115 other than UE 115-d to provide carrier reporting.

[0151] At 640, UE 115-d can perform carrier measurements on the carriers associated with low-frequency band connection 605 and high-frequency band transmission 635 (and also on high-frequency band transmission 630 or other transmissions detectable by UE 115-d). For example, UE 115-d can measure the timing difference between the timing of high-frequency band transmission 635 and the timing of low-frequency band transmission 625 of second base station 105-h. As noted above, in some cases, UE 115-d can measure the timing difference between the start times of reference subframes, time slots, symbols, samples, or other timing elements in low-frequency band transmission 625 and high-frequency band transmission 635. UE 115-d can use a common timing reference to determine the timing difference.

[0152] UE 115-d may additionally measure other information described herein related to determining whether UE 115-d will use asynchronous CA and the amount of delay to be observed when performing uplink signaling in asynchronous CA operation mode. For example, at 640, UE 115-d may additionally measure timing advance, one or more channel quality metrics, RF illumination level, and battery charge level for uplink transmission to the first base station 105-g using low-band connection 605, determine whether UE 115-d can use high-band transmission 635 to establish a UL connection, and measure the frequency difference between the low-band transmission and the high-band transmission 635 associated with low-band connection 605.

[0153] At 645, UE 115-d can format a carrier report. The carrier report may include any information measured at 640 or otherwise determined, such as an indication of the measured timing difference between high-frequency band transmission 635 and low-frequency band transmission 625. In some cases, UE 115-d may provide the indication of the timing difference as a time difference (e.g., as a number of nanoseconds, microseconds, etc.). In other cases, UE 115-d may provide the indication of the timing difference as a sampling period (e.g., the high-frequency band sampling period or the basic time unit sampling period T discussed above). s The number of measurements is provided. If UE 115-d detects two or more high-frequency band transmissions from two or more base stations 105, the timing difference for each measurement can be included in the carrier report. The carrier report may also include the identifier of the second base station 105-h (and any other measured base station 105), which may be, for example, a cell identifier (cell ID) associated with the second base station 105-h.

[0154] UE 115-d can send carrier report 650 to the first base station 105-g. In some cases, a low-band connection can be used to send timing reports. In some cases, MAC-CE or RRC measurement reports can be used to send timing reports.

[0155] At position 655, the first base station 105-g can receive carrier report 650 and determine the connection mode that UE 115-d can use to communicate with the second base station 105-h (such as high-frequency band communication with the second base station 105-h). For example, as described herein, the first base station 105-g can determine whether UE 115-d should use dual-connection mode, synchronous CA mode, or asynchronous CA mode for communication with the second base station 105-h. In some cases, the first base station 105-g can determine that UE 115-d should use asynchronous CA for communication with the second base station 105-h.

[0156] The first base station 105-g can send connection configuration information 660 to the UE 115-d. The connection configuration information 660 may include an indication of the connection mode that the UE 115-d can use for communication with the second base station 105-h (e.g., an indication that the UE 115-d will use asynchronous CA for communication with the second base station 105-h). If the UE 115-d will use asynchronous CA, the connection configuration information 660 may also include an indication of the minimum delay that the UE 115-d should observe between receiving high-frequency band transmissions from the second base station 105-h and sending related uplink transmissions to the first base station 105-g. For example, connection configuration information 660 may include an indication of the minimum delay that UE 115-d should observe between receiving packets from the second base station 105-h (e.g., via a high-frequency band carrier supported by the second base station 105-h) and acknowledging (e.g., ACK or NACK) sending packets to the first base station 105-g (e.g., via a low-frequency band carrier supported by the first base station 105-g, which corresponds to low-frequency band connection 605). In some cases, connection configuration information 660 may be transmitted at least partially via control signaling such as RRC signaling.

[0157] UE 115-d can establish a high-frequency band connection 665 with the second base station 105-h using a high-frequency band carrier according to the connection configuration information 660. Thereafter, UE 115-d can continue to monitor carrier-related information (e.g., the timing difference between the high-frequency band connection 665 and the low-frequency band connection 605) and send additional carrier reports or otherwise indicate updated carrier-related information to the first base station 105-g or the second base station 105-h. The first base station 105-g or the second base station 105-h can determine the minimum reporting delay or configuration information for updating the new connection mode and send it to UE 115-d.

[0158] Figure 7 A block diagram 700 of a wireless device 705 supporting asynchronous CA according to various aspects of this disclosure is shown. Wireless device 705 may be an example of various aspects of base station 105 as described herein. Wireless device 705 may include a receiver 710, a base station communication manager 715, and a transmitter 720. Wireless device 705 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0159] Receiver 710 can receive packets, user data, or information such as control information associated with various information channels (e.g., control channels, data channels, and information channels related to asynchronous CA). It can transmit information to other components of device 705. Receiver 710 can be a reference... Figure 10Examples of various aspects of the transceiver 1035 are described. The receiver 710 can utilize a single antenna or a set of antennas.

[0160] Base station communication manager 715 can be used as a reference Figure 10 Examples of various aspects of the described base station communication manager 1015.

[0161] At least some of the sub-components of the base station communication manager 715 and / or its various sub-components can be implemented using hardware, software executed by a processor, firmware, or any combination thereof. If implemented using software executed by a processor, the functionality of at least some of the sub-components of the base station communication manager 715 and / or its various sub-components can be performed by a general-purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware component, or any combination thereof, designed to perform the functions described in this disclosure. At least some of the sub-components of the base station communication manager 715 and / or its various sub-components can be physically located in various locations, including being distributed such that some functions are implemented by one or more physical devices at different physical locations. In some examples, according to various aspects of this disclosure, at least some of the sub-components of the base station communication manager 715 and / or its various sub-components can be separate and distinct components. In other examples, at least some of the base station communication manager 715 and / or its various sub-components may be combined with one or more other hardware components (including, but not limited to, I / O components, transceivers, network servers, other computing devices, one or more other components described in this disclosure, or combinations thereof) in accordance with various aspects of this disclosure.

[0162] The base station communication manager 715 can perform the following operations: establish a first connection with a user equipment (UE) using a first carrier in a first frequency band; receive from the UE a timing difference between a transmission in the first frequency band and one or more transmissions in a second frequency band higher than the first frequency band; and determine, based on the timing difference, whether the UE 115 should use asynchronous CA mode for communication using a second carrier in the second frequency band.

[0163] Transmitter 720 can transmit signals generated by other components of the device. In some examples, transmitter 720 can be co-located with receiver 710 in a transceiver module. For example, transmitter 720 can be a reference... Figure 10 Examples of various aspects of the transceiver 1035 are described. The transmitter 720 can utilize a single antenna or a set of antennas.

[0164] Figure 8A block diagram 800 of a wireless device 805 supporting asynchronous CA is shown according to various aspects of this disclosure. The wireless device 805 may be as described with reference to... Figure 7 Examples of various aspects of the described wireless device 705 or base station 105. Wireless device 805 may include a receiver 810, a base station communication manager 815, and a transmitter 820. Wireless device 805 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0165] Receiver 810 can receive packets, user data, or information such as control information associated with various information channels (e.g., control channels, data channels, and information channels related to asynchronous CA). It can transmit information to other components of device 805. Receiver 810 can be a reference... Figure 10 Examples of various aspects of the transceiver 1035 are described. The receiver 810 can utilize a single antenna or a set of antennas.

[0166] Base station communication manager 815 can be used as a reference Figure 10 Examples of various aspects of the described base station communication manager 1015.

[0167] The base station communication manager 815 may also include a low-frequency band connection manager 825, a timing indicator component 830, and a connection mode manager 835.

[0168] The low-frequency band connection manager 825 can use the first carrier in the first frequency band to establish a first connection with UE 115.

[0169] The timing indication component 830 can receive from the UE 115 a timing difference between a transmission in a first frequency band and one or more transmissions in a second frequency band higher than the first frequency band. In some cases, the timing indication component 830 can also receive one or more updated timing differences from the UE 115. In some cases, the timing difference includes: a timing offset between a first subframe on a first carrier and a second subframe on a second carrier; a timing offset between a first timeslot on a first carrier and a second timeslot on a second carrier; a timing offset between a first symbol on a first carrier and a second symbol on a second carrier; a timing offset between one or more samples corresponding to the first symbol on the first carrier and one or more samples corresponding to the second symbol on the second carrier; or any combination thereof.

[0170] The connection mode manager 835 can determine whether the UE 115 should use asynchronous CA mode for communication using a second carrier in a second frequency band based on a timing difference. In some cases, determining whether the UE 115 should use asynchronous CA mode for communication using a second carrier in a second frequency band based on a timing difference includes comparing the timing difference with a threshold timing difference. In some cases, the connection mode manager 835 can determine the threshold timing difference based on the subcarrier spacing associated with the first or second frequency band.

[0171] The connection mode manager 835 can further determine whether the UE 115 should use asynchronous CA mode for communication using the second carrier in the second frequency band based on the frequency difference between the first and second frequency bands.

[0172] The connection mode manager 835 can further determine whether UE 115 should use asynchronous CA mode for communication using the second carrier in the second frequency band based on whether UE 115 can establish an uplink connection on the second carrier. The connection mode manager 835 can compare a channel quality metric for the second carrier with a threshold value to determine whether UE 115 can establish an uplink connection on the second carrier. The connection mode manager 835 can receive an indication from UE 115 regarding whether UE 115 can establish an uplink connection on the second carrier. In some cases, the connection mode manager 835 can configure UE 115 to attempt a random access procedure via the second carrier using a specified transmit power to determine whether UE 115 can establish an uplink connection on the second carrier.

[0173] The connection mode manager 835 can also determine whether the UE 115 should use asynchronous CA mode for communication using the second carrier in the second frequency band based on whether the second carrier can be aggregated with the first carrier. In some cases, determining whether the second carrier can be aggregated with the first carrier includes determining the quality of the backhaul connection between the first base station 105 corresponding to the first carrier and the second base station 105 corresponding to the second carrier.

[0174] Transmitter 820 can transmit signals generated by other components of device 805. In some examples, transmitter 820 can be co-located with receiver 810 in a transceiver module. For example, transmitter 820 can be a reference... Figure 10 Examples of various aspects of the transceiver 1035 are described. The transmitter 820 can utilize a single antenna or a set of antennas.

[0175] Figure 9 A block diagram 900 of a base station communication manager 915 supporting asynchronous CA according to various aspects of this disclosure is shown. The base station communication manager 915 may be a reference... Figure 7 , Figure 8 and Figure 10 Examples of aspects of the described base station communication manager 715, base station communication manager 815, or base station communication manager 1015. Base station communication manager 915 may include a low-frequency band connection manager 920, a timing indication component 925, a connection mode manager 930, a configuration manager 935, and a reporting delay manager 940. Each of these modules may communicate directly or indirectly with each other (e.g., via one or more buses).

[0176] The low-frequency band connection manager 920 can use the first carrier in the first frequency band to establish a first connection with UE 115.

[0177] Timing indication component 925 can receive from UE 115 a timing difference between a transmission in a first frequency band and one or more transmissions in a second frequency band higher than the first frequency band. In some cases, timing indication component 830 can also receive one or more updated timing differences from UE 115. In some cases, the timing difference includes: a timing offset between a first subframe on a first carrier and a second subframe on a second carrier; a timing offset between a first timeslot on a first carrier and a second timeslot on a second carrier; a timing offset between a first symbol on a first carrier and a second symbol on a second carrier; a timing offset between one or more samples corresponding to the first symbol on the first carrier and one or more samples corresponding to the second symbol on the second carrier; or any combination thereof.

[0178] The connection mode manager 930 can determine whether the UE 115 should use asynchronous CA mode for communication using a second carrier in a second frequency band based on a timing difference. In some cases, determining whether the UE 115 should use asynchronous CA mode for communication using a second carrier in a second frequency band based on a timing difference includes comparing the timing difference with a threshold timing difference. In some cases, the connection mode manager 835 can determine the threshold timing difference based on the subcarrier spacing associated with the first or second frequency band.

[0179] The connection mode manager 930 can further determine whether UE 115 should use asynchronous CA mode for communication using the second carrier in the second frequency band based on the frequency difference between the first and second frequency bands.

[0180] The connection mode manager 930 can further determine whether UE 115 should use asynchronous CA mode for communication using the second carrier in the second frequency band based on whether UE 115 can establish an uplink connection on the second carrier. The connection mode manager 930 can compare a channel quality metric for the second carrier with a threshold value to determine whether UE 115 can establish an uplink connection on the second carrier. The connection mode manager 930 can receive an indication from UE 115 regarding whether UE 115 can establish an uplink connection on the second carrier. In some cases, the connection mode manager 930 can configure UE 115 to attempt a random access procedure via the second carrier using a specified transmit power to determine whether UE 115 can establish an uplink connection on the second carrier.

[0181] The connection mode manager 930 can also determine whether the UE 115 should use asynchronous CA mode for communication using the second carrier in the second frequency band based on whether the second carrier can be aggregated with the first carrier. In some cases, determining whether the second carrier can be aggregated with the first carrier includes determining the quality of the backhaul connection between the first base station 105 corresponding to the first carrier and the second base station 105 corresponding to the second carrier.

[0182] Configuration Manager 935 can perform the following operations: based on the determination that UE 115 will use asynchronous CA mode, configure UE 115 to observe at least a minimum delay between receiving packets via a second carrier and reporting acknowledgments for packets via a first carrier; configure UE 115 to report acknowledgments via PUSCH or PUCCH; configure UE 115 to observe at least a minimum delay by at least partially using the RRC protocol; configure UE 115 to observe at least a minimum update delay between receiving subsequent packets via a second carrier and reporting acknowledgments for subsequent packets via a first carrier; and based on the determination that UE 115 will use asynchronous CA mode, configure UE 115 to observe at least a minimum delay between receiving packets via a second carrier and reporting CSI corresponding to the packets via a first carrier.

[0183] The report delay manager 940 can determine the minimum delay based on: timing difference, first subcarrier spacing associated with a first carrier, second subcarrier spacing associated with a second carrier, or any combination thereof. In some cases, the timing difference includes a timing offset between a first reference time slot on the first carrier and a second reference time slot on the second carrier, and the method further includes determining the minimum delay based on: timing difference, duration of a first time slot for the first carrier, duration of a second time slot for the second carrier, uplink timing advance for the first carrier, duration of the uplink portion of a time slot in the first carrier, processing time for packets, or any combination thereof. In some cases, the timing difference includes a timing offset between a first reference timeslot on the first carrier and a second reference timeslot on the second carrier, and configuring UE 115 to observe at least the minimum delay includes applying a rounding function to a quantity based on: the timing difference, the duration of the first timeslot for the first carrier, the duration of the second timeslot for the second carrier, the uplink timing advance for the first carrier, the duration of the uplink portion of the timeslot in the first carrier, the packet processing time, or any combination thereof; the reporting delay manager 940 can configure acknowledgment reporting parameters for UE 115 based on the output of the rounding function. In some cases, the duration of the second timeslot for the second carrier is for the downlink portion of the timeslot in the second carrier. In some cases, the duration of the uplink portion of the timeslot in the first carrier is based on the amount of uplink data to be transmitted in the timeslot in the first carrier.

[0184] Figure 10 A diagram is shown of a system 1000 including a device 1005 supporting asynchronous CA according to various aspects of this disclosure. Device 1005 may be as described above (e.g., refer to...). Figure 7 and Figure 8 Examples of wireless devices 705, 805, or base station 105 described herein, or components including wireless devices 705, 805, or base station 105, are described. Device 1005 may include components for two-way voice and data communication, including components for transmitting and receiving communications, including: base station communication manager 1015, processor 1020, memory 1025, software 1030, transceiver 1035, antenna 1040, network communication manager 1045, and inter-station communication manager 1050. These components may communicate electronically via one or more buses (e.g., bus 1010). Device 1005 may communicate wirelessly with one or more UEs 115.

[0185] Processor 1020 may include intelligent hardware devices (e.g., general-purpose processors, DSPs, central processing units (CPUs), microcontrollers, ASICs, FPGAs, programmable logic devices, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some cases, processor 1020 may be configured to use a memory controller to operate a memory array. In other cases, the memory controller may be integrated into processor 1020. Processor 1020 may be configured to execute computer-readable instructions stored in memory to perform various functions (e.g., functions or tasks supporting asynchronous CA).

[0186] Memory 1025 may include random access memory (RAM) and read-only memory (ROM). Memory 1025 may store computer-readable, computer-executable software 1030 including instructions that, when executed, cause the processor to perform the various functions described herein. In some cases, in addition, memory 1025 may also include a basic input / output (I / O) system (BIOS) that controls basic hardware or software operations (such as interaction with peripheral components or devices).

[0187] Software 1030 may include code for implementing various aspects of this disclosure, including code for supporting asynchronous CA. Software 1030 may be stored in a non-transitory computer-readable medium (e.g., system memory or other memory). In some cases, software 1030 may not be directly executable by a processor, but may enable a computer (e.g., when compiled and executed) to perform the functions described herein.

[0188] Transceiver 1035 can communicate bidirectionally via one or more antennas, wired or wireless links as described above. For example, transceiver 1035 can represent a wireless transceiver and can communicate bidirectionally with another wireless transceiver. Transceiver 1035 may also include a modem for modulating packets and providing modulated packets to the antenna for transmission, and for demodulating packets received from the antenna.

[0189] In some cases, wireless device 1035 may include a single antenna 1040. However, in other cases, device 1035 may have more than one antenna 1040, which is capable of transmitting or receiving multiple wireless transmissions concurrently.

[0190] The network communication manager 1045 can manage communication with the core network (e.g., via one or more wired backhaul links). For example, the network communication manager 1045 can manage the transmission of data communication to client devices (such as one or more UEs 115).

[0191] Inter-site communication manager 1050 can manage communication with other base stations 105 and may include a controller or scheduler for cooperating with other base stations 105 to control communication with UE 115. For example, inter-site communication manager 1050 can coordinate the scheduling of transmissions to UE 115 for various interference mitigation techniques such as beamforming or joint transmission. In some examples, inter-site communication manager 1050 may provide an X2 interface within Long Term Evolution (LTE) / LTE-A wireless communication network technology to facilitate communication between base stations 105.

[0192] Figure 11 A block diagram 1100 of a wireless device 1105 supporting asynchronous CA according to various aspects of this disclosure is shown. Wireless device 1105 may be an example of various aspects of UE 115 as described herein. Wireless device 1105 may include a receiver 1110, a UE communication manager 1115, and a transmitter 1120. Wireless device 1105 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0193] Receiver 1110 can receive packets, user data, or information such as control information associated with various information channels (e.g., control channels, data channels, and information channels related to asynchronous CA). It can transmit information to other components of the device. Receiver 1110 can be a reference... Figure 14 Examples of various aspects of the transceiver 1435 are described. The receiver 1110 may utilize a single antenna or a set of antennas.

[0194] UE Communication Manager 1115 can be used as a reference Figure 14 Examples of various aspects of the UE communication manager 1415 are described.

[0195] At least some of the sub-components of the UE communication manager 1115 and / or its various sub-components may be implemented using hardware, software executed by a processor, firmware, or any combination thereof. If implemented using software executed by a processor, the functionality of at least some of the sub-components of the UE communication manager 1115 and / or its various sub-components may be performed by a general-purpose processor, DSP, ASIC, FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware component, or any combination thereof designed to perform the functions described in this disclosure. At least some of the sub-components of the UE communication manager 1115 and / or its various sub-components may be physically located in various locations, including being distributed such that portions of the functionality are implemented by one or more physical devices at different physical locations. In some examples, according to various aspects of this disclosure, at least some of the sub-components of the UE communication manager 1115 and / or its various sub-components may be separate and distinct components. In other examples, at least some of the UE communication manager 1115 and / or its various sub-components may be combined with one or more other hardware components (including, but not limited to, I / O components, transceivers, network servers, other computing devices, one or more other components described in this disclosure, or combinations thereof) in accordance with various aspects of this disclosure.

[0196] The UE communication manager 1115 can use a first carrier in a first frequency band to establish a first connection with the base station 105; monitor one or more transmissions in a second frequency band, which is at a higher frequency than the first frequency band; measure the timing difference between the transmissions in the first frequency band and one or more transmissions in the second frequency band; send an indication of the timing difference to the base station; and receive an indication from the base station 105 regarding the use of asynchronous CA mode for communication utilizing the second carrier in the second frequency band.

[0197] Transmitter 1120 can transmit signals generated by other components of the device. In some examples, transmitter 1120 may be co-located with receiver 1110 in a transceiver module. For example, transmitter 1120 may be a reference... Figure 14 Examples of various aspects of the transceiver 1435 are described. The transmitter 1120 can utilize a single antenna or a set of antennas.

[0198] Figure 12 A block diagram 1200 of a wireless device 1205 supporting asynchronous CA is shown according to various aspects of this disclosure. The wireless device 1205 may be as described with reference to... Figure 11Examples of various aspects of the described wireless device 1105 or UE 115. Wireless device 1205 may include a receiver 1210, a UE communication manager 1215, and a transmitter 1220. Wireless device 1205 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0199] Receiver 1210 can receive packets, user data, or information such as control information associated with various information channels (e.g., control channels, data channels, and information channels related to asynchronous CA). It can transmit information to other components of the device. Receiver 1210 can be a reference... Figure 14 Examples of various aspects of the transceiver 1435 are described. The receiver 1210 may utilize a single antenna or a set of antennas.

[0200] UE Communication Manager 1215 can be used as a reference Figure 14 Examples of various aspects of the UE communication manager 1415 are described.

[0201] The UE communication manager 1215 may also include a low-frequency band connection manager 1225, a timing component 1230, a timing indication component 1235, and a connection mode manager 1240.

[0202] The low-frequency band connection manager 1225 can use the first carrier in the first frequency band to establish a first connection with the base station 105.

[0203] Timing component 1230 can monitor one or more transmissions in a second frequency band, which operates at a higher frequency than the first frequency band; and can measure the timing difference between transmissions in the first frequency band and one or more transmissions in the second frequency band. Timing component 1230 can measure the timing difference at a sampling rate associated with the second frequency band. In some cases, the timing difference includes: a timing offset between a first subframe on the first carrier and a second subframe on the second carrier; a timing offset between a first timeslot on the first carrier and a second timeslot on the second carrier; a timing offset between a first symbol on the first carrier and a second symbol on the second carrier; a timing offset between one or more samples corresponding to the first symbol on the first carrier and one or more samples corresponding to the second symbol on the second carrier; or any combination thereof. In some cases, measuring the timing difference includes deriving the timing difference based on a common timing reference used to measure the timing of transmissions in both the first and second frequency bands. Timing component 1230 can also measure uplink timing advance for the first carrier, measure packet processing time, or measure the duration of a second timeslot for the second carrier.

[0204] The timing indication component 1235 can send an indication of timing difference to the base station. In some cases, the indication of timing difference is sent in the MAC-CE or in the RRC measurement report. The timing indication component 1235 can also send an indication of uplink timing advance, an indication of processing time, and an indication of the duration of the second timeslot used for the second carrier to the base station. In some cases, the timing indication component 1235 can send one or more updated timing differences to the base station.

[0205] The connection mode manager 1240 can receive instructions from the base station 105 to use asynchronous CA mode for communication utilizing the second carrier in the second frequency band.

[0206] Transmitter 1220 can transmit signals generated by other components of the device. In some examples, transmitter 1220 can be co-located with receiver 1210 in a transceiver module. For example, transmitter 1220 can be a reference... Figure 14 Examples of various aspects of the transceiver 1435 are described. The transmitter 1220 can utilize a single antenna or a set of antennas.

[0207] Figure 13 A block diagram 1300 of a UE communication manager 1315 supporting asynchronous CA according to various aspects of this disclosure is shown. The UE communication manager 1315 may be a reference... Figure 11 , Figure 12 and Figure 14 Examples of various aspects of the described UE communication manager 1415 are provided. The UE communication manager 1315 may include a low-band connectivity manager 1320, a timing component 1325, a timing indication component 1330, a connectivity mode manager 1335, a reporting delay manager 1340, an acknowledgment manager 1345, a channel quality reporting manager 1350, an uplink capability manager 1355, a maximum permissible illumination manager 1360, and a battery manager 1365. Each of these modules may communicate directly or indirectly with each other (e.g., via one or more buses).

[0208] The low-frequency band connection manager 1320 can use the first carrier in the first frequency band to establish a first connection with the base station 105.

[0209] Timing component 1325 can monitor one or more transmissions in a second frequency band, which operates at a higher frequency than the first frequency band; and measure the timing difference between the transmissions in the first frequency band and one or more transmissions in the second frequency band. In some cases, the timing difference includes: a timing offset between a first subframe on the first carrier and a second subframe on the second carrier; a timing offset between a first timeslot on the first carrier and a second timeslot on the second carrier; a timing offset between a first symbol on the first carrier and a second symbol on the second carrier; a timing offset between one or more samples corresponding to the first symbol on the first carrier and one or more samples corresponding to the second symbol on the second carrier; or any combination thereof. In some cases, measuring the timing difference includes deriving the timing difference based on a common timing reference used to measure the timing of transmissions in both the first and second frequency bands. Timing component 1325 can also measure uplink timing advance for the first carrier, measure packet processing time, measure the duration of the second timeslot for the second carrier, and measure the timing difference according to the sampling rate associated with the second frequency band.

[0210] The timing indication component 1330 can send to the base station an indication of timing difference, send to the base station one or more updated timing differences, send to the base station an indication of uplink timing advance, send to the base station an indication of processing time, and send to the base station an indication of the duration of a second timeslot used for the second carrier. In some cases, the indication of timing difference is sent in the MAC-CE or in the RRC measurement report.

[0211] The connection mode manager 1335 can receive instructions from the base station 105 to use asynchronous CA mode for communication utilizing the second carrier in the second frequency band.

[0212] The report delay manager 1340 can receive from the base station 105 the minimum delay to be observed between receiving a packet via the second carrier and reporting an acknowledgment for the packet via the first carrier, the minimum delay to be observed between receiving a subsequent packet via the second carrier and reporting an acknowledgment for the subsequent packet via the first carrier, the minimum delay to be received at least in part via the RRC protocol, and a second minimum delay to be observed between receiving a packet via the second carrier and reporting the CSI corresponding to the packet via the first carrier.

[0213] The confirmation manager 1345 can report confirmations via PUSCH or PUCCH.

[0214] The channel quality report manager 1350 can send channel quality metrics for the second carrier to the base station 105.

[0215] The uplink capability manager 1355 can send an indication to the base station 105 regarding whether an uplink connection on the second carrier can be established. In some cases, the uplink capability manager 1355 can receive a specified transmit power from the base station 105, attempt a random access procedure via the second carrier using the specified transmit power, and determine whether an uplink connection on the second carrier can be established based on whether the random access procedure is successful.

[0216] The maximum permissible illumination manager 1360 can determine whether an uplink connection on the second carrier can be established by comparing the radio frequency illumination level associated with the uplink connection on the second carrier with the maximum permissible illumination level.

[0217] The battery manager 1365 can determine whether an uplink connection on a second carrier can be established by comparing the battery charge level associated with the UE 115 with a minimum battery charge level.

[0218] Figure 14 A diagram of a system 1400 including a device 1405 supporting asynchronous CA is shown according to various aspects of this disclosure. Device 1405 may be as described above (e.g., refer to...). Figure 1 The device 1405 may include an example of UE 115 or components of a UE. The device 1405 may include components for bidirectional voice and data communication, including components for transmitting and receiving communications, such as: a UE communication manager 1415, a processor 1420, a memory 1425, software 1430, a transceiver 1435, an antenna 1440, and an I / O controller 1445. These components may communicate electronically via one or more buses (e.g., bus 1410). The device 1405 may communicate wirelessly with one or more base stations 105.

[0219] Processor 1420 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, processor 1420 may be configured to use a memory controller to operate a memory array. In other cases, the memory controller may be integrated into processor 1420. Processor 1420 may be configured to execute computer-readable instructions stored in memory to perform various functions (e.g., functions or tasks supporting asynchronous CA).

[0220] Memory 1425 may include RAM and ROM. Memory 1425 may store computer-readable, computer-executable software 1430 including instructions that, when executed, cause a processor to perform the various functions described herein. In some cases, in addition, memory 1425 may also include a BIOS that controls basic hardware or software operations (such as interaction with peripheral components or devices).

[0221] Software 1430 may include code for implementing various aspects of this disclosure, including code for supporting asynchronous CA. Software 1430 may be stored in a non-transitory computer-readable medium (such as system memory or other memory). In some cases, software 1430 may not be directly executable by a processor, but may enable a computer (e.g., when compiled and executed) to perform the functions described herein.

[0222] Transceiver 1435 can communicate bidirectionally via one or more antennas, wired or wireless links as described above. For example, transceiver 1435 can represent a wireless transceiver and can communicate bidirectionally with another wireless transceiver. Transceiver 1435 may also include a modem for modulating packets and providing modulated packets to the antenna for transmission, and for demodulating packets received from the antenna.

[0223] In some cases, wireless device 1405 may include a single antenna 1440. However, in other cases, device 1405 may have more than one antenna 1440, which is capable of transmitting or receiving multiple wireless transmissions concurrently.

[0224] I / O controller 1445 can manage input and output signals for device 1405. I / O controller 1445 can also manage peripheral devices not integrated into device 1405. In some cases, I / O controller 1445 can represent a physical connection or port to an external peripheral device. In some cases, I / O controller 1445 can utilize, for example... This can be an operating system such as a modem, keyboard, mouse, touchscreen, or similar device, or an operating system known to exist. In other cases, the I / O controller 1445 may represent or interact with a modem, keyboard, mouse, touchscreen, or similar device. In some cases, the I / O controller 1445 may be implemented as part of a processor. In some cases, a user may interact with the device 1405 via the I / O controller 1445 or via hardware components controlled by the I / O controller 1445.

[0225] Figure 15A flowchart illustrating a method 1500 for asynchronous CA according to various aspects of this disclosure is shown. Operation of method 1500 can be implemented by a base station 105 or its components as described herein. For example, operation of method 1500 can be implemented by, as referred to... Figures 7 to 10 The base station communication manager described herein is used to perform these functions. In some examples, base station 105 may execute a set of code to control the functional elements of the device to perform the functions described below. Alternatively, base station 105 may use dedicated hardware to perform aspects of the functions described below.

[0226] At point 1505, base station 105 may use a first carrier in the first frequency band to establish a first connection with user equipment (UE). The operation of 1505 can be performed according to the method described herein. In some examples, aspects of the operation of 1505 may be determined by reference to... Figures 7 to 10 The low-frequency band connection manager is described and executed.

[0227] At 1510, base station 105 can receive from UE 115 the timing difference between a transmission in a first frequency band and one or more transmissions in a second frequency band higher than the first frequency band. Operation of 1510 can be performed according to the method described herein. In some examples, aspects of the operation of 1510 can be derived from, as referenced... Figures 7 to 10 The described timed indicator component is used for execution.

[0228] At point 1515, base station 105 can determine, at least in part, whether UE 115 will use asynchronous CA mode for communication using a second carrier in a second frequency band, based on the timing difference. The operation of 1515 can be performed according to the method described herein. In some examples, aspects of the operation of 1515 can be determined by reference to... Figures 7 to 10 The described connection mode manager is used for execution.

[0229] Figure 16 A flowchart illustrating a method 1600 for asynchronous CA according to various aspects of this disclosure is shown. Operation of method 1600 can be implemented by a base station 105 or its components as described herein. For example, operation of method 1600 can be implemented by, as referred to... Figures 7 to 10 The base station communication manager described herein is used to perform these functions. In some examples, base station 105 may execute a set of code to control the functional elements of the device to perform the functions described below. Alternatively, base station 105 may use dedicated hardware to perform aspects of the functions described below.

[0230] At point 1605, base station 105 may use a first carrier in the first frequency band to establish a first connection with user equipment (UE). The operation of 1605 can be performed according to the method described herein. In some examples, aspects of the operation of 1605 may be determined by reference to... Figures 7 to 10The low-frequency band connection manager is described and executed.

[0231] At 1610, base station 105 can receive from the UE the timing difference between a transmission in the first frequency band and one or more transmissions in a second frequency band higher than the first frequency band. Operation of 1610 can be performed according to the method described herein. In some examples, aspects of the operation of 1610 can be derived from, as referenced... Figures 7 to 10 The described timed indicator component is used for execution.

[0232] At 1615, base station 105 can determine, at least in part, whether UE 115 will use asynchronous CA mode for communication using a second carrier in a second frequency band, based on the timing difference. The operation of 1615 can be performed according to the method described herein. In some examples, aspects of the operation of 1615 can be determined by reference to... Figures 7 to 10 The described connection mode manager is used for execution.

[0233] At 1620, base station 105 can configure UE 115 to observe at least a minimum delay between receiving packets via the second carrier and reporting acknowledgments for packets via the first carrier, based at least in part on the determination that UE 115 will use asynchronous CA mode. Operation of 1620 can be performed according to the method described herein. In some examples, aspects of operation of 1620 can be determined by reference to... Figures 7 to 10 The configuration manager or report delay manager described is used to perform this.

[0234] Figure 17 A flowchart illustrating a method 1700 for asynchronous CA according to various aspects of this disclosure is shown. The operation of method 1700 can be implemented by a UE 115 or its components as described herein. For example, the operation of method 1700 can be implemented by, as referred to... Figures 11 to 14 The UE communication manager described herein is used to perform these functions. In some examples, the UE 115 may execute a set of code to control the functional elements of the device to perform the functions described below. Alternatively, the UE 115 may use dedicated hardware to perform aspects of the functions described below.

[0235] At 1705, UE 115 can use the first carrier in the first frequency band to establish a first connection with base station 105. The operation of 1705 can be performed according to the method described herein. In some examples, aspects of the operation of 1705 can be derived from, as referenced... Figures 11 to 14 The low-frequency band connection manager is described and executed.

[0236] At 1710, UE 115 can monitor one or more transmissions in a second frequency band, which operates at a higher frequency than the first frequency band. Operation of 1710 can be performed according to the methods described herein. In some examples, aspects of operation of 1710 can be derived from, as referenced... Figures 11 to 14 The described timed component is used for execution.

[0237] At 1715, UE 115 can measure the timing difference between a transmission in the first frequency band and one or more transmissions in the second frequency band. Operation of 1715 can be performed according to the method described herein. In some examples, aspects of the operation of 1715 can be determined by reference to... Figures 11 to 14 The described timed component is used for execution.

[0238] At point 1720, UE 115 can send an indication of timing difference to the base station. The operation at 1720 can be performed according to the method described herein. In some examples, aspects of the operation at 1720 can be determined by referring to... Figures 11 to 14 The described timed indicator component is used for execution.

[0239] At 1725, UE 115 can receive from base station 105 an instruction regarding the use of asynchronous CA mode for communication utilizing a second carrier in a second frequency band. Operation at 1725 can be performed according to the method described herein. In some examples, aspects of operation at 1725 can be determined by reference to... Figures 11 to 14 The described connection mode manager is used for execution.

[0240] Figure 18 A flowchart illustrating a method 1800 for asynchronous CA according to various aspects of this disclosure is shown. The operation of method 1800 can be implemented by a UE 115 or its components as described herein. For example, the operation of method 1800 can be implemented by, as referred to... Figures 11 to 14 The UE communication manager described herein is used to perform these functions. In some examples, the UE 115 may execute a set of code to control the functional elements of the device to perform the functions described below. Alternatively, the UE 115 may use dedicated hardware to perform aspects of the functions described below.

[0241] At point 1805, UE 115 can use the first carrier in the first frequency band to establish a first connection with base station 105. The operation at point 1805 can be performed according to the method described herein. In some examples, aspects of the operation at point 1805 can be derived from, as referenced... Figures 11 to 14 The low-frequency band connection manager is described and executed.

[0242] At 1810, UE 115 can monitor one or more transmissions in a second frequency band, which operates at a higher frequency than the first frequency band. Operation of 1810 can be performed according to the methods described herein. In some examples, aspects of operation of 1810 can be determined by reference to... Figures 11 to 14 The described timed component is used for execution.

[0243] At 1815, UE 115 can measure the timing difference between a transmission in the first frequency band and one or more transmissions in the second frequency band. Operation of 1815 can be performed according to the method described herein. In some examples, aspects of the operation of 1815 can be derived from, as referenced... Figures 11 to 14 The described timed component is used for execution.

[0244] At point 1820, UE 115 can send an indication of the timing difference to the base station. The operation at point 1820 can be performed according to the method described herein. In some examples, aspects of the operation at point 1820 can be determined by referring to... Figures 11 to 14 The described timed indicator component is used for execution.

[0245] At point 1825, UE 115 can receive from base station 105 an instruction regarding the use of asynchronous CA mode for communication utilizing a second carrier in a second frequency band. Operation at point 1825 can be performed according to the method described herein. In some examples, aspects of operation at point 1825 can be determined by reference to... Figures 11 to 14 The described connection mode manager is used for execution.

[0246] At 1830, UE 115 can receive from base station 105 the minimum delay to be observed between receiving a packet via the second carrier and reporting an acknowledgment for the packet via the first carrier. Operation at 1830 can be performed according to the method described herein. In some examples, aspects of operation at 1830 can be derived from, as referenced... Figures 11 to 14 The report is described and the delay manager is used for execution.

[0247] It should be noted that the methods described above describe possible implementations, and the operations and steps can be rearranged or otherwise modified, and other implementations are possible. Furthermore, aspects from two or more methods can be combined.

[0248] The techniques described in this article can be used in various wireless communication systems, such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA), and other systems. CDMA systems can implement radio technologies such as CDMA 2000 and Universal Terrestrial Radio Access (UTRA). CDMA2000 encompasses the IS-2000, IS-95, and IS-856 standards. Versions of IS-2000 are often referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is often referred to as CDMA2000 1xEV-DO, High-Speed ​​Packet Data (HRPD), etc. UTRA includes Wideband CDMA (W-CDMA) and other variations of CDMA. TDMA systems can implement radio technologies such as Global System for Mobile Communications (GSM).

[0249] OFDMA systems can implement radio technologies such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, and Flash-OFDM. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS). LTE and LTE-A are versions of UMTS using E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, NR, and GSM are described in documents from an organization called the 3rd Generation Partnership Project (3GPP). CDMA2000 and UMB are described in documents from an organization called the 3rd Generation Partnership Project 2 (3GPP2). The technologies described herein can be used with the systems and radio technologies mentioned above, as well as other systems and radio technologies. While aspects of LTE or NR systems may be described for illustrative purposes, and the terminology of LTE or NR may be used in much of the description, the technologies described herein are applicable to applications beyond LTE or NR.

[0250] Macro cells typically cover a relatively large geographic area (e.g., a radius of several kilometers) and can allow unrestricted access by UE 115 with a service subscription to a network provider. In contrast to macro cells, small cells can be associated with a lower-power base station 105 and can operate in the same or different (e.g., licensed, unlicensed, etc.) frequency bands as macro cells. Depending on the examples, small cells can include pico cells, femto cells, and microcells. For example, a pico cell can cover a small geographic area and can allow unrestricted access by UE 115 with a service subscription to a network provider. A femto cell can also cover a small geographic area (e.g., a residential area) and can provide restricted access by UE 115 associated with that femto cell (e.g., UE 115 in a Closed Subscriber Group (CSG), UE 115 for a user in a residential area, etc.). An eNB for a macro cell can be referred to as a macro eNB. An eNB for a small cell can be referred to as a small cell eNB, pico eNB, femto eNB, or home eNB. eNB can support one or more (e.g., two, three, four, etc.) cells, and can also support communication using one or more component carriers.

[0251] The wireless communication system 100 or more systems described herein can support synchronous or asynchronous operation. For synchronous operation, base stations 105 can have similar frame timing, and transmissions from different base stations 105 can be approximately time-aligned. For asynchronous operation, base stations 105 can have different frame timing, and transmissions from different base stations 105 may not be time-aligned. The techniques described herein can be used for both synchronous and asynchronous operation.

[0252] The information and signals described herein can be represented using any of a variety of different techniques and methods. For example, the data, instructions, commands, information, signals, bits, symbols, and chips mentioned throughout the above description can be represented by voltage, current, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof.

[0253] The various illustrative blocks and modules described herein can be implemented or executed using a general-purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional 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 combined with a DSP core, or any other such configuration).

[0254] The functions described herein can be implemented using hardware, software executed by a processor, firmware, or any combination thereof. If implemented using software executed by a processor, the functions can be stored as one or more instructions or code on or transmitted through a computer-readable medium. Other examples and implementations are within the scope of this disclosure and the appended claims. For example, due to the nature of software, the functions described above can be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination of these. Features implementing the functions can also be physically located in various locations, including being distributed such that different parts of the functions are implemented in different physical locations.

[0255] Computer-readable media includes both non-transitory computer storage media and communication media, with communication media encompassing any medium that facilitates the transfer of computer programs from one place to another. Non-transitory storage media can be any available medium accessible by a general-purpose computer or a special-purpose computer. By way of example, and not limitation, non-transitory computer-readable media can include random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory, compressed optical disc (CD) ROM or other optical disc storage, disk storage or other magnetic storage devices, or any other non-transitory medium capable of carrying or storing desired units of program code in the form of instructions or data structures, and accessible by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Furthermore, any connection is appropriately referred to as computer-readable media. For example, if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included within the definition of media. As used herein, disks and optical discs include CDs, laser discs, optical discs, digital multifunction discs (DVDs), floppy disks, and Blu-ray discs. Disks typically copy data magnetically, while optical discs use lasers to copy data optically. The combinations described above are also included within the scope of computer-readable media.

[0256] As used herein (including in the claims), the word "or" in a list of items (e.g., a list of items ending with a phrase such as "at least one of" or "one or more of") indicates an inclusive list, such that a list 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). Furthermore, as used herein, the phrase "based on" should not be construed as a reference to a closed set of conditions. For example, an exemplary step described as "based on condition A" may be based on both condition A and condition B without departing from the scope of this disclosure. In other words, as used herein, the phrase "based on" should be interpreted in the same manner as the phrase "at least partially based on".

[0257] In the accompanying drawings, similar components or features may have the same reference numerals. Furthermore, various components of the same type can be distinguished by a dash followed by a second reference numeral, used to differentiate between similar components. If only the first reference numeral is used in the specification, the description applies to any one of the similar components having the same first reference numeral, without regard to the second reference numeral or other subsequent reference numerals.

[0258] This document describes exemplary configurations with reference to the accompanying drawings, but does not represent all examples that can be implemented or that are within the scope of the claims. The term "exemplary" as used herein means "serving as an example, instance, or illustration," not "preferred" or "advantageous over other examples." Detailed descriptions include specific details for the purpose of providing an understanding of the described techniques. However, these techniques may be implemented 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.

[0259] The description herein is provided to enable those skilled in the art to implement or use the present disclosure. Various modifications to the present disclosure will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other variations without departing from the scope of the disclosure. Therefore, the present disclosure is not limited to the examples and designs described herein, but is to be given the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. An apparatus for wireless communication at a base station (BS), comprising: processor; Memory that communicates electronically with the processor; as well as Instructions stored in the memory and executable by the processor to cause the device to perform the following operations: A first carrier is used to establish a first connection between the BS and the user equipment (UE), wherein there is a timing difference between transmissions using the first carrier and transmissions using a second carrier, the second carrier being associated with a frequency range different from that of the first carrier; and The timing difference is used at least in part to send an indication to the UE that the UE will subsequently use asynchronous carrier aggregation mode to establish a second connection for communication via the second carrier.

2. The apparatus according to claim 1, wherein, The timing difference is at least partially based on the timing offset between the first time slot of the first carrier and the second time slot of the second carrier.

3. The apparatus according to claim 1, wherein: The first carrier has a first subcarrier spacing (SCS); and The second carrier has a second SCS that is different from the first SCS.

4. The apparatus according to claim 1, wherein: The first carrier is associated with the first cell; and The second carrier is associated with a second cell that is different from the first cell.

5. The apparatus according to claim 1, wherein, The instructions, executable by the processor, cause the device to: at least in part via radio resource control signaling, send the indication that the UE will subsequently use the asynchronous carrier aggregation mode to establish the second connection.

6. The apparatus according to claim 1, wherein, The asynchronous carrier aggregation mode corresponds to: the second carrier being used for downlink signaling and the first carrier being used for uplink control signaling associated with the downlink signaling, the uplink control signaling being delayed relative to the downlink signaling at least in part based on the timing difference.

7. The apparatus according to claim 1, wherein, The instructions are also executable by the processor to cause the device to: The UE receives an acknowledgment for a packet on the second carrier via the first carrier, wherein the acknowledgment received via the first carrier is at least in part based on the second connection using the asynchronous carrier aggregation mode.

8. The apparatus according to claim 1, wherein, The instructions are also executable by the processor to cause the device to: Channel quality information for the second carrier is received via the first carrier, wherein the channel quality information for the second carrier received via the first carrier is at least partially based on the second connection using the asynchronous carrier aggregation mode.

9. An apparatus for wireless communication at a user equipment (UE), comprising: processor; Memory that communicates electronically with the processor; as well as Instructions stored in the memory and executable by the processor to cause the device to perform the following operations: A first carrier is used to establish a first connection between the UE and the base station (BS); The indication that the UE will subsequently use an asynchronous carrier aggregation mode to establish a second connection for communication via the second carrier is received, at least in part based on the timing difference between a transmission using the first carrier and a transmission using the second carrier, the second carrier being associated with a different frequency range than the first carrier; as well as Upon receiving the instruction to use the asynchronous carrier aggregation mode, the second connection is established, at least in part, based on the instruction and according to the asynchronous carrier aggregation mode.

10. The apparatus according to claim 9, wherein, The timing difference is at least partially based on the timing offset between the first time slot of the first carrier and the second time slot of the second carrier.

11. The apparatus according to claim 9, wherein: The first carrier has a first subcarrier spacing (SCS); and The second carrier has a second SCS that is different from the first SCS.

12. The apparatus according to claim 9, wherein: The first carrier is associated with the first cell; and The second carrier is associated with a second cell that is different from the first cell.

13. The apparatus according to claim 9, wherein, The instructions, executable by the processor, cause the device to: receive, at least in part via radio resource control signaling, an indication that the UE will subsequently use the asynchronous carrier aggregation mode to establish the second connection.

14. The apparatus according to claim 9, wherein, The instructions are also executable by the processor to cause the device to: Receive downlink signaling via the second carrier; and Uplink control signaling associated with the downlink signaling is transmitted via the first carrier, the uplink control signaling being delayed relative to the downlink signaling at least in part based on the timing difference, wherein the uplink control signaling associated with the downlink signaling transmitted via the first carrier is at least in part based on the second connection using the asynchronous carrier aggregation mode.

15. The apparatus according to claim 9, wherein, The instructions are also executable by the processor to cause the device to: To receive packets via the second carrier; and An acknowledgment for the packet is transmitted via the first carrier, wherein the acknowledgment transmitted via the first carrier is at least in part based on the second connection using the asynchronous carrier aggregation mode.

16. The apparatus according to claim 9, wherein, The instructions are also executable by the processor to cause the device to: Channel quality information for the second carrier is transmitted via the first carrier, wherein the channel quality information for the second carrier transmitted via the first carrier is at least partially based on the second connection using the asynchronous carrier aggregation mode.

17. A method for wireless communication at a base station (BS), comprising: A first carrier is used to establish a first connection between the BS and the user equipment (UE), wherein there is a timing difference between transmissions using the first carrier and transmissions using a second carrier, the second carrier being associated with a frequency range different from that of the first carrier; and The timing difference is used at least in part to send an indication to the UE that the UE will subsequently use asynchronous carrier aggregation mode to establish a second connection for communication via the second carrier.

18. The method according to claim 17, wherein, The timing difference is at least partially based on the timing offset between the first time slot of the first carrier and the second time slot of the second carrier.

19. The method of claim 17, wherein: The first carrier has a first subcarrier spacing (SCS); and The second carrier has a second SCS that is different from the first SCS.

20. The method of claim 17, wherein: The first carrier is associated with the first cell; and The second carrier is associated with a second cell that is different from the first cell.

21. The method according to claim 17, wherein, The indication that the UE will subsequently use the asynchronous carrier aggregation mode to establish the second connection is sent at least in part via radio resource control signaling.

22. The method according to claim 17, wherein, The asynchronous carrier aggregation mode corresponds to: the second carrier being used for downlink signaling and the first carrier being used for uplink control signaling associated with the downlink signaling via the second carrier, the uplink control signaling being delayed relative to the downlink signaling at least in part based on the timing difference.

23. The method of claim 17, further comprising: An acknowledgment corresponding to a packet on the second carrier is received via the first carrier, wherein the acknowledgment received via the first carrier is at least in part based on the second connection using the asynchronous carrier aggregation mode.

24. A method for wireless communication at a user equipment (UE), comprising: A first carrier is used to establish a first connection between the UE and the base station (BS); The indication that the UE will subsequently use an asynchronous carrier aggregation mode to establish a second connection for communication via the second carrier is received, at least in part based on the timing difference between a transmission using the first carrier and a transmission using the second carrier, the second carrier being associated with a different frequency range than the first carrier; as well as Upon receiving the instruction to use the asynchronous carrier aggregation mode, the second connection is established, at least in part, based on the instruction and according to the asynchronous carrier aggregation mode.

25. The method according to claim 24, wherein, The timing difference is at least partially based on the timing offset between the first time slot of the first carrier and the second time slot of the second carrier.

26. The method of claim 24, wherein: The first carrier has a first subcarrier spacing (SCS); and The second carrier has a second SCS that is different from the first SCS.

27. The method of claim 24, wherein: The first carrier is associated with the first cell; and The second carrier is associated with a second cell that is different from the first cell.

28. The method according to claim 24, wherein, The indication that the UE will subsequently use the asynchronous carrier aggregation mode to establish the second connection is received at least in part via radio resource control signaling.

29. The method of claim 24, further comprising: Downlink signaling is received via the second carrier; as well as Uplink control signaling associated with the downlink signaling is transmitted via the first carrier, the uplink control signaling being delayed relative to the downlink signaling at least in part based on the timing difference, wherein the uplink control signaling associated with the downlink signaling transmitted via the first carrier is at least in part based on the second connection using the asynchronous carrier aggregation mode.

30. The method of claim 24, further comprising: Packets are received via the second carrier. as well as An acknowledgment for the packet is transmitted via the first carrier, wherein the acknowledgment transmitted via the first carrier is at least in part based on the second connection using the asynchronous carrier aggregation mode.

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