Patent Application
20230156788
Various example embodiments relate to methods and apparatuses for determining channel access for uplink transmissions.
In addition to dynamically scheduled and configured grant uplink (UL) transmissions, periodic or semi-persistent (P/SP) UL transmissions for information such as Scheduling Request (SR), Sounding Reference Signal (SRS), Channel State Information (CSI), and Hybrid Automatic Repeat Request Acknowledge (HARQ-ACK) may also be supported in a communication system such as a New Radio (NR or 5G) system.
In a first aspect, disclosed is a method including determining a duration of a gap between an uplink transmission of a first apparatus and a downlink transmission of a second apparatus before the uplink transmission and in a channel occupancy time of the second apparatus in a case where the uplink transmission falls within the channel occupancy time, and determining at least one of a channel access type and a cyclic prefix extension for the uplink transmission according to the duration of the gap. For example, the method may be performed in the first apparatus such as a mobile device or user equipment (UE), and the second apparatus may be a base station (e.g. gNB in NR system).
In some example embodiments, the method may further include receiving information for determining the duration of the gap, and the information may include a structure of the channel occupancy time. For example, the information for determining the duration of the gap may be carried on a group common physical downlink control channel (GC-PDCCH).
In some example embodiments, the method may further include receiving information for determining the duration of the gap, and the information may include one or more of channel access type for at least one uplink transmission, gap duration for the at least one uplink transmission, a slot format indicator, channel occupancy time duration indicator, and cyclic prefix extension length for the at least one uplink transmission. For example, the information for determining the duration of the gap may be carried on GC-PDCCH.
In some example embodiments, the channel access type may be a first type in a case where the duration of the gap is less than or equal to a first value and a duration of the uplink transmission is less than a second value. For example, the first type may be Type 2C, the first value may be about 16 μs, and the second value may be about 0.584 ms.
In some example embodiments, the channel access type may be a second type in a case where the duration of the gap is equal to a third value. For example, the second type may be Type 2B and the third value may be about 16 μs.
In some example embodiments, the channel access type may be a third type in a case where the duration of the gap is at least a fourth value. For example, the third type may be Type 2A and the fourth value may be about 25 μs.
In some example embodiments, the channel access type is a fourth type in a case where the uplink transmission falls outside of the channel occupancy time. For example, the fourth type may be Type 1.
In some example embodiments, the method may further include extending a cyclic prefix of the uplink transmission to reduce the duration of the gap in a case where the duration of the gap is more than a fifth value and less than a sum of the fifth value and a duration of an Orthogonal Frequency Division Multiplexing (OFDM) symbol. For example, the fifth value may be about 16 μs.
In some example embodiments, the method may further include dropping the uplink transmission in a case where the duration of the gap is less than or equal to a sixth value and a duration of the uplink transmission is more than a seventh value. For example, the sixth value may be about 16 μs and the seventh value may be about 0.584 ms.
In some example embodiments, the method may further include receiving, for example via a radio resource control signaling, information on a configuration for time and frequency resources for the uplink transmission.
In some example embodiments, the uplink transmission may be a periodic or a semi-persistent uplink transmission.
In a second aspect, also disclosed is a method including transmitting information for determining a duration of a gap between an uplink transmission of a first apparatus and a downlink transmission of a second apparatus before the uplink transmission and in a channel occupancy time of the second apparatus in a case where the uplink transmission falls within the channel occupancy time, at least one of a channel access type and a cyclic prefix extension for the uplink transmission being determined based on the duration of the gap. For example, the method may be performed in the second apparatus such as a base station (e.g. gNB in NR system), and the first apparatus may be a UE.
In some example embodiments, the information may include a structure of the channel occupancy time. For example, the information may be transmitted via GC-PDCCH.
In some example embodiments, the information may include one or more of channel access type for at least one uplink transmission, gap duration for the at least one uplink transmission, a slot format indicator, channel occupancy time duration indicator, and cyclic prefix extension length for the at least one uplink transmission. For example, the information may be transmitted via GC-PDCCH.
In some example embodiments, the method may further include transmitting, for example via a radio resource control signaling, information on a configuration for time and frequency resources for the uplink transmission.
In some example embodiments, the uplink transmission may be a periodic or a semi-persistent uplink transmission.
In a third aspect, also disclosed is an apparatus including means for determining a duration of a gap between an uplink transmission of the apparatus and a downlink transmission of another apparatus before the uplink transmission and in a channel occupancy time of another apparatus in a case where the uplink transmission falls within the channel occupancy time, and means for determining at least one of a channel access type and a cyclic prefix extension for the uplink transmission according to the duration of the gap. For example, this apparatus may be at least a part of mobile device or UE, and the another apparatus may be at least a part of a base station.
In some example embodiments, the apparatus may further include means for receiving information for determining the duration of the gap, the information including a structure of the channel occupancy time. For example, the information for determining the duration of the gap may be carried on GC-PDCCH.
In some example embodiments, the apparatus may further include means for receiving information for determining the duration of the gap, where the information may include one or more of channel access type for at least one uplink transmission, gap duration for the at least one uplink transmission, a slot format indicator, channel occupancy time duration indicator, and cyclic prefix extension length for the at least one uplink transmission. For example, the information for determining the duration of the gap may be carried on the GC-PDCCH.
In some example embodiments, the channel access type may be a first type in a case where the duration of the gap is less than or equal to a first value and a duration of the uplink transmission is less than a second value. For example, the first type may be Type 2C, the first value may be about 16 μs, and the second value may be about 0.584 ms.
In some example embodiments, the channel access type may be a second type in a case where the duration of the gap is equal to a third value. For example, the second type may be Type 2B and the third value may be about 16 μs.
In some example embodiments, the channel access type may be a third type in a case where the duration of the gap is at least a fourth value. For example, the third type may be Type 2A and the fourth value may be about 25 μs.
In some example embodiments, the channel access type is a fourth type in a case where the uplink transmission falls outside of the channel occupancy time. For example, the fourth type may be Type 1.
In some example embodiments, the apparatus may further include means for extending a cyclic prefix of the uplink transmission to reduce the duration of the gap in a case where the duration of the gap is more than a fifth value and less than a sum of the fifth value and a duration of an OFDM symbol. For example, the fifth value may be about 16 μs.
In some example embodiments, the apparatus may further include means for dropping the uplink transmission in a case where the duration of the gap is less than or equal to a sixth value and a duration of the uplink transmission is more than a seventh value. For example, the sixth value may be about 16 μs and the seventh value may be about 0.584 ms.
In some example embodiments, the apparatus may further include means for receiving, for example via a radio resource control signaling, information on a configuration for time and frequency resources for the uplink transmission.
In some example embodiments, the uplink transmission may be a periodic or a semi-persistent uplink transmission.
In a fourth aspect, also disclosed is an apparatus including means for transmitting information for determining a duration of a gap between a downlink transmission of the apparatus in a channel occupancy time of of the apparatus and an uplink transmission of another apparatus after the downlink transmission in a case where the uplink transmission falls within the channel occupancy time, at least one of a channel access type and a cyclic prefix extension for the uplink transmission being determined based on the duration of the gap. For example, this apparatus may be at least a part of a base station (e.g. gNB in NR system), and the another apparatus may be at least a part of a UE.
In some example embodiments, the information may include a structure of the channel occupancy time. For example, the information may be transmitted via GC-PDCCH.
In some example embodiments, the information may include one or more of channel access type for at least one uplink transmission, gap duration for the at least one uplink transmission, a slot format indicator, channel occupancy time duration indicator, and cyclic prefix extension length for the at least one uplink transmission. For example, the information may be transmitted via GC-PDCCH.
In some example embodiments, the apparatus may further include means for transmitting, for example via a radio resource control signaling, information on a configuration for time and frequency resources for the uplink transmission.
In some example embodiments, the uplink transmission is a periodic or a semi-persistent uplink transmission.
In a fifth aspect, also disclosed is an apparatus including at least one processor and at least one memory. The at least one memory may include computer program code, and the at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to perform any method in the above first aspect. For example, this apparatus may correspond to the first apparatus in any method in the above first aspect, and may be at least a part of mobile device or UE.
In a sixth aspect, also disclosed is an apparatus including at least one processor and at least one memory. The at least one memory may include computer program code, and the at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to perform any method in the above second aspect. For example, this apparatus may correspond to the second apparatus in the any method in the above second aspect, and may be at least a part of a base station (e.g. gNB in NR system).
In a seventh aspect, also disclosed is a computer readable medium including program instructions for causing an apparatus to perform at least any method in the above first aspect. For example, this apparatus may correspond to the first apparatus in the any method in the above first aspect, and may be at least a part of a UE.
In an eighth aspect, also disclosed is a computer readable medium including program instructions for causing an apparatus to perform at least any method in the above second aspect. For example, this apparatus may correspond to the second apparatus in the any method in the above second aspect, and may be at least a part of a base station (e.g. gNB in NR system).
Some example embodiments will now be described, by way of non-limiting examples, with reference to the accompanying drawings.
Various types of channel access or Listen Before Talk (LBT) may be applied to transmissions in different cases. For example, the types of channel access or LBT supported in the 3GPP standards (for example, 3GPP TS37.213) may include Type 2C for an immediate transmission without LBT for up to a certain period (e.g. 584 μs), Type 2B for a single-shot LBT with a measurement duration (e.g. 16 μs), Type 2A for a single-shot LBT with another measurement duration (e.g. 25 μs), Type 1 for a LBT with exponential back-off, and so on.
For an UL transmission of P/SP UL transmissions of a UE, for example, the channel access type may be determined by the UE based on whether the UL transmission falls within a channel occupancy time (COT) of a base station (e.g. a gNB in the NR system).
In an example, the UE may receive information on a structure of the COT of the base station via GC-PDCCH, which may include indications such as slots for uplink transmissions in the COT, slots for downlink transmissions in the COT, durations of respective slots in the COT, and so on, for example as shown in
In another example, the UE may apply the channel access type and/or CP extension length within or outside of the COT according to the RRC configuration from the base station. For example, according to the RRC configuration, the UE may apply a specified channel access type for the intended UL transmissions within the COT and another specified channel access type for the intended UL transmissions outside of the COT, respectively.
As shown in
Through the example method 200, for example, the first apparatus may be allowed for making use of different types of channel access or LBT (i.e. switching among different types) when the intended UL transmission is within the COT, and a dynamic configuration of the CP extension may also be allowed, so that the P/SP UL transmissions of the UE may be adaptable dynamically for different use cases. Thus, for example, the UE may be enabled to use aggressive/efficient channel access scheme when transmitting P/SP UL signals.
Moreover, through the example method 200, for example, some or all UEs may apply the substantially same channel access mechanism, so that Frequency Division Multiplexing of UL transmissions of different UEs may be simplified. Further, for example, the UE may select suitable channel access type and CP extension adaptively, so that additional Layer 1 control signalling may be avoided.
In some embodiments, the information used in the step 210 for determining the duration of the gap may include the structure of COT of the base station. For example, the UE may receive such information via GC-PDCCH.
For example, as shown in
Then, for any intended UL transmission of P/SP UL transmissions of the UE 310, for example, in the step 210 or an additional step of the example method 200, or even before the execution of the example method 200, the UE 310 may utilize the information derived from the configuration 330 and/or the structure of the COT derived from the information carried by the GC-PDCCH 340, to determine (1) whether the intended UL transmission falls within the COT of the base station 320, and (2) the position of the intended UL transmission with respect to a DL transmission e.g. the closest DL transmission preceding the intended UL transmission in the COT), that is, the duration of the gap between the intended UL transmission and the last DL transmission.
For example, based on the detected GC-PDCCH 340, the UE 310 may determine the structure of COT 400 of the base station 320, as shown in
Further, the UE 310 may determine the position of the intended UL transmission with respect to a DL transmission before the intended UL transmission, for example based on the structure of COT 400 and the configuration 330. For example, for the intended UL transmission 420, a duration of gap (or a gap duration, or a distance in time) 470 between the intended UL transmission 420 and the DL transmission 410, for example from the end of the DL transmission 410 (e.g. the last DL transmission in the DL slot before the UL transmission 420) to the start of the intended UL transmission 420, may be determined, where the DL transmission 410 in the DL slot may be adjacent to and before the UL slot including the intended UL transmission 420 and may be the closest DL transmission preceding the intended UL transmission 420. Similarly, for the intended UL transmission 430, a duration of gap 480 between the intended UL transmission 430 and the DL transmission 410 may be determined, and for the intended UL transmission 450, a duration of gap 490 between the intended UL transmission 450 and the DL transmission 440 may be determined.
It is appreciated that the manner of determining whether the intended UL transmission falls within the COT and the duration gap for an intended UL transmission are not limited to the above examples. In various embodiments, any suitable manner and suitable information may be utilized to determine whether an intended UL transmission of P/SP UL transmissions of the UE falls in the base station initiated channel occupancy, and to determine the gap duration for any intended UL transmission of P/SP UL transmissions of the UE. More examples will be described hereafter.
As shown in
In some embodiments, for an UL transmission of P/SP UL transmissions of the UE, the channel access type may be determined as a first type (for example, Type 2C) in a case where the duration of the gap is less than or equal to a first value (for example, a value about 16 μs) and a duration of the UL transmission is less than a second value (for example, a value about 0.584 ms). For example, for the intended UL transmission 420 in
In some embodiments, for an UL transmission of P/SP UL transmissions of the UE, the channel access type may be determined as a second type (for example, Type 2B) in a case where the duration of the gap is equal to a third value (for example, a value about 16 μs). For example, if the determined gap duration 490 for the intended UL transmission 450 in
In some embodiments, for an UL transmission of P/SP UL transmissions of the UE, the channel access type may be determined as a third type (for example, Type 2A) in a case where the duration of the gap is at least a fourth value (for example, a value about 25 μs). For example, if the determined gap duration 480 for the intended UL transmission 430 in
In some embodiments, for an UL transmission of P/SP UL transmissions of the UE, the channel access type may be determined as a fourth type (for example, Type 1) in a case where the UL transmission falls outside of the COT. For example, for the intended UL transmission 460 outside of the COT 400 in
In some embodiments, for an UL transmission of P/SP UL transmissions of the UE, the CP of the UL transmission may be extended to reduce the duration of the gap in a case where the duration of the gap is more than a fifth value (for example, a value about 16 μs) and less than a sum of the fifth value and a duration of an Orthogonal Frequency Division Multiplexing (OFDM) symbol. Thus, the duration of the gap may be reduced effectively by the CP extension to be an expected length, for example 16 μs, so as to allow for the UE to switch the channel access type for the UL transmission from the above third type to the above first type or the above second type.
For example, as shown in
Similarly, if the gap duration 530 is larger than 25 μs, the UE 310 may prolong its CP with the part 540, so that the new gap duration 550 between the extended UL transmission (including the parts 520 and 540) and the DL transmission 510 may be reduced to 25 μs, or to 16 μs or less. Then, the UE 310 may use one of the above first type (e.g. Type 2C), the second type (e.g. Type 2B), and the third type (e.g. Type 2A), depending on the new gap duration 550 and the duration of the extended UL transmission (including the parts 520 and 540).
In some embodiments, for an UL transmission of P/SP UL transmissions of the UE, the UL transmission may be dropped in a case where the duration of the gap is less than or equal to a sixth value (for example, a value about 16 μs) and a duration of the UL transmission is more than a seventh value (for example, a value about 0.584 ms).
For example, as shown in
As described above with several illustrated but not limited examples, through the example method 200, for example, the UE can make use of different types of channel access or LBT (i.e. switching among different types) when the intended UL transmission is within the COT, and a dynamic configuration of the CP extension may also be allowed, so that the P/SP UL transmissions of the UE may be adaptable dynamically for different use cases. Thus, for example, the UE may be enabled to use aggressive/efficient channel access scheme when transmitting P/SP UL signals. Moreover, through the example method 200, for example, some or all UEs may apply the substantially same channel access mechanism, so that Frequency Division Multiplexing of UL transmissions of different UEs may be simplified. Further, through the example method 200, the UE may select suitable channel access type and CP extension adaptively, so that additional Layer 1 control signalling may be avoided.
It is appreciated that, considering tolerances, various values mentioned above such as the above first value and second value may be a value in a value range based on a reference value (e.g. 16 μs, or 25 μs, or 0.584 ms). For example, “being less than or equal to 16 μs” may also mean “being less than or equal to a value in a value range including 16 μs and considering tolerances or predetermined thresholds/parameters”, and “a value about 16 μs” may mean for example 16 μs, or a value about 16 μs such as 15.985 μs and 16.101 μs, or other reasonable value in a value range including 16 μs and considering tolerances or predetermined threshold/parameters.
It is also appreciated that the example method 200 is not limited to any of the above examples or embodiments. For example, the example method may further include receiving, for example via a RRC signaling, information on a configuration for time and frequency resources for the uplink transmission, for example as shown in
For example, as shown in
For example, for the intended UL transmissions 420, 430, and 450 as shown in
Thus, for example, the UE may determine the channel access type or LBT type by parsing the received information, or the determination of the duration gap or CP extension for an intended UL transmission may be simplified. For example, it may be useful to include gap duration for one or more intended UL transmissions (e.g. between the last DL transmission of the ongoing DL burst in a COT and the intended UL transmission) may be useful, for example, in a case where the base station fills part of the gap using a partial OFDM symbol transmission to create a gap of a specific duration.
It is appreciated that any of the above examples or embodiments may be combined. For example, for a first intended UL transmission and a second intended UL transmission, the UE may detect GC-PDCCH to determine the structure of COT and then determine the duration gap and in turn at least one of the channel access type/LBT type and CP extension, similarly to the procedure as shown in
Corresponding to the example method 200,
As shown in
In some embodiments, for example as shown in
As shown in
In various example embodiments, the at least one processor 910 in the example apparatus 900 may include, but not limited to, at least one hardware processor, including at least one microprocessor such as a central processing unit (CPU), a portion of at least one hardware processor, and any other suitable dedicated processor such as those developed based on for example Field Programmable Gate Array (FPGA) and Application Specific Integrated Circuit (ASIC). Further, the at least one processor 910 may also include at least one other circuitry or element not shown in
In various example embodiments, the at least one memory 920 in the example apparatus 900 may include at least one storage medium in various forms, such as a volatile memory and/or a non-volatile memory. The volatile memory may include, but not limited to, for example, a random-access memory (RAM), a cache, and so on. The non-volatile memory may include, but not limited to, for example, a read only memory (ROM), a hard disk, a flash memory, and so on. Further, the at least memory 920 may include, but are not limited to, an electric, a magnetic, an optical, an electromagnetic, an infrared, or a semiconductor system, apparatus, or device or any combination of the above.
Further, in various example embodiments, the example apparatus 900 may also include at least one other circuitry, element, and interface, for example at least one I/O interface, at least one antenna element, and the like.
In various example embodiments, the circuitries, parts, elements, and interfaces in the example apparatus 900, including the at least one processor 910 and the at least one memory 920, may be coupled together via any suitable connections including, but not limited to, buses, crossbars, wiring and/or wireless lines, in any suitable ways, for example electrically, magnetically, optically, electromagnetically, and the like.
The structure of the apparatus on the side of the UE 310 is not limited to the above example apparatus 900.
As shown in
In some example embodiments, examples of means 1010 and 1020 may include circuitries. For example, an example of means 1010 may include a circuitry configured to perform the step 210 of the example method 200, and an example of means 1020 may include a circuitry configured to perform the step 220 of the example method 200. In some example embodiments, examples of means may also include software modules and any other suitable function entities.
In some embodiments, the example apparatus 1000 may further include one or more additional means for receiving the above information for determining the duration of the gap, for extending a cyclic prefix of the uplink transmission in some case, and/or for dropping the uplink transmission in some case.
The term “circuitry” throughout this disclosure may refer to one or more or all of the following: (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry); (b) combinations of hardware circuits and software, such as (as applicable) (i) a combination of analog and/or digital hardware circuit(s) with software/firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions); and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation. This definition of circuitry applies to one or all uses of this term in this disclosure, including in any claims. As a further example, as used in this disclosure, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.
As shown in
In various example embodiments, the at least one processor 1110 in the example apparatus 1100 may include, but not limited to, at least one hardware processor, including at least one microprocessor such as a CPU, a portion of at least one hardware processor, and any other suitable dedicated processor such as those developed based on for example FPGA and ASIC. Further, the at least one processor 1110 may also include at least one other circuitry or element not shown in
In various example embodiments, the at least one memory 1120 in the example apparatus 1100 may include at least one storage medium in various forms, such as a volatile memory and/or a non-volatile memory. The volatile memory may include, but not limited to, for example, a RAM, a cache, and so on. The non-volatile memory may include, but not limited to, for example, a ROM, a hard disk, a flash memory, and so on. Further, the at least memory 1120 may include, but are not limited to, an electric, a magnetic, an optical, an electromagnetic, an infrared, or a semiconductor system, apparatus, or device or any combination of the above.
Further, in various example embodiments, the example apparatus 1100 may also include at least one other circuitry, element, and interface, for example at least one I/O interface, at least one antenna element, and the like.
In various example embodiments, the circuitries, parts, elements, and interfaces in the example apparatus 1100, including the at least one processor 1110 and the at least one memory 1120, may be coupled together via any suitable connections including, but not limited to, buses, crossbars, wiring and/or wireless lines, in any suitable ways, for example electrically, magnetically, optically, electromagnetically, and the like.
As shown in
In various example embodiments, examples of means 1210 may include circuitries. For example, an example of means 1210 may include a circuitry configured to perform the step 810 of the example method 800. In some example embodiments, examples of means may also include software modules and any other suitable function entities.
Another example embodiment may relate to computer program codes or instructions which may cause an apparatus to perform at least respective methods described above, such as computer program codes or instructions causing a UE to perform at least the above example method 200, and computer program codes or instructions causing a base station to perform at least the above example method 800.
Another example embodiment may be related to a computer readable medium having such computer program codes or instructions stored thereon. In various example embodiments, such a computer readable medium may include at least one storage medium in various forms such as a volatile memory and/or a non-volatile memory. The volatile memory may include, but not limited to, for example, a RAM, a cache, and so on. The non-volatile memory may include, but not limited to, a ROM, a hard disk, a flash memory, and so on.
Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” The word “coupled”, as generally used herein, refers to two or more elements that may be either directly connected, or connected by way of one or more intermediate elements. Likewise, the word “connected”, as generally used herein, refers to two or more elements that may be either directly connected, or connected by way of one or more intermediate elements. Additionally, the words “herein,” “above,” “below,” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. Where the context permits, words in the description using the singular or plural number may also include the plural or singular number respectively. The word “or” in reference to a list of two or more items, that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list.
Moreover, conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” “for example,” “such as” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or states are included or are to be performed in any particular embodiment.
While some example embodiments have been described, these embodiments have been presented by way of example, and are not intended to limit the scope of the disclosure. Indeed, the apparatus, methods, and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the disclosure. For example, while blocks are presented in a given arrangement, alternative embodiments may perform similar functionalities with different components and/or circuit topologies, and some blocks may be deleted, moved, added, subdivided, combined, and/or modified. At least one of these blocks may be implemented in a variety of different ways. The order of these blocks may also be changed. Any suitable combination of the elements and acts of the various embodiments described above can be combined to provide further embodiments. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosure.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2020/083870 | 4/9/2020 | WO |
