User equipment power saving when monitoring search space

Abstract

Example methods and apparatuses for reducing power consumption of a user equipment (UE) are described. One example method includes receiving, by a UE, an indication for determining a PDCCH candidate ordering for a plurality of PDCCH candidates in a physical downlink control channel (PDCCH) search space. The UE determines a first PDCCH candidate from the plurality of PDCCH candidates based on the indication. In response to determining that no downlink control information (DCI) for the UE is found in the first PDCCH candidate, the UE determines a second PDCCH candidate from the plurality of PDCCH candidates based on the indication. In response to determining that DCI for the UE is found in the second PDCCH candidate, the UE processes the DCI.

Description

[0001] Cross-referencing related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 062,306, filed August 6, 2020. The entire disclosure of the above application is incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to monitoring the physical downlink control channel (PDCCH) search space, and in certain embodiments, to systems and methods for reducing power consumption of user equipment when monitoring the PDCCH search space. Background Technology

[0004] Reduced capability (RedCap) user equipment (UE) is a new radio (NR) entity that serves relatively low-end services but has requirements that differ from typical cellular UEs, such as long battery life. RedCap UEs are envisioned for use in at least three different scenarios: industrial sensors, video surveillance, and wearable devices.

[0005] In these scenarios, Redcap UEs may be power-sensitive. Some services (e.g., ultra-reliable low-latency communication (URLLC) or extended reality (XR)) increase the UE's monitoring cycle and / or frequency, thereby increasing power consumption when monitoring the PDCCH search space. Summary of the Invention

[0006] This disclosure relates to methods and systems for monitoring the PDCCH search space, and in certain embodiments, to systems and methods for reducing UE power consumption when monitoring the PDCCH search space.

[0007] In a first implementation, the method for monitoring the PDCCH search space includes: receiving an indication from a user equipment (UE) for determining a PDCCH candidate ordering for a plurality of PDCCH candidates in the PDCCH search space; the UE determining a first PDCCH candidate from the plurality of PDCCH candidates based on the indication; the UE determining that no downlink control information (DCI) for the UE is found in the first PDCCH candidate; in response to determining that no DCI for the UE is found in the first PDCCH candidate, the UE determining a second PDCCH candidate from the plurality of PDCCH candidates based on the indication; the UE determining that a DCI for the UE is found in the second PDCCH candidate; and processing the DCI in response to determining that a DCI for the UE is found in the second PDCCH candidate.

[0008] In a second implementation, an electronic device includes: at least one processor; and one or more memories coupled to the at least one processor and storing program instructions executed by the at least one processor to perform: receiving an indication for determining a PDCCH candidate ordering for a plurality of PDCCH candidates in a PDCCH search space; determining a first PDCCH candidate from the plurality of PDCCH candidates based on the indication; determining that no downlink control information (DCI) for the UE is found in the first PDCCH candidate; in response to determining that no DCI for the UE is found in the first PDCCH candidate, determining a second PDCCH candidate from the plurality of PDCCH candidates based on the indication; determining that a DCI for the UE is found in the second PDCCH candidate; and processing the DCI in response to determining that a DCI for the UE is found in the second PDCCH candidate.

[0009] In a third implementation, a non-transitory computer-readable medium stores program instructions, which are executed by at least one processor to: receive an indication for determining a PDCCH candidate ordering for a plurality of PDCCH candidates in a PDCCH search space; determine a first PDCCH candidate from the plurality of PDCCH candidates based on the indication; determine that no downlink control information (DCI) for the UE is found in the first PDCCH candidate; in response to determining that no DCI for the UE is found in the first PDCCH candidate, determine a second PDCCH candidate from the plurality of PDCCH candidates based on the indication; determine that the DCI for the UE is found in the second PDCCH candidate; and process the DCI in response to determining that the DCI for the UE is found in the second PDCCH candidate. Attached Figure Description

[0010] To gain a more complete understanding of this disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:

[0011] Figure 1 An example wireless communication system is shown;

[0012] Figure 2 An example arrangement of PDCCH candidates in the search space is shown;

[0013] Figure 3 A flowchart illustrating an example process for monitoring the PDCCH search space is shown;

[0014] Figure 4 A flowchart illustrating an example process for monitoring the PDCCH search space based on aggregation level is shown;

[0015] Figure 5 A flowchart illustrating an example process for monitoring the PDCCH search space based on estimated SINR is shown;

[0016] Figure 6 A flowchart illustrating an example process for monitoring the PDCCH search space is shown; and

[0017] Figure 7 A block diagram of an example computer system is shown. Detailed Implementation

[0018] The following detailed description describes monitoring the PDCCH search space and reducing the power consumption of the UE while monitoring the search space, and is presented to enable those skilled in the art to make and use the disclosed subject matter in the context of one or more particular implementations.

[0019] Various modifications, alterations, and substitutions can be made to the disclosed implementations, and these will be readily apparent to those skilled in the art. Furthermore, the general principles defined can be applied to other implementations and applications without departing from the scope of this disclosure. In some cases, unnecessary details necessary for understanding the described subject matter may be omitted so as not to obscure one or more described implementations, since such details are within the skill of those skilled in the art. This disclosure is not intended to be limited to the described or illustrated implementations, but is given the widest scope consistent with the described principles and features.

[0020] The PDCCH search space refers to the area within the downlink resource grid that can carry a PDCCH. Possible locations within the search space that can carry a PDCCH are called PDCCH candidates. Each PDCCH carries a DCI and is identified by a Radio Network Temporary Identifier (RNTI). The RNTI is implicitly encoded in the cyclic redundancy check (CRC) appendage of the DCI. The UE can monitor the PDCCH search space and search it to find the DCI. The UE can use a trial-and-error approach (also known as blind decoding) to attempt to decode the PDCCH / DCI using different parameter values ​​(e.g., CCE index, aggregation level, RNTI). Each blind decoding consumes power, and the base station is free to dynamically select any specific blind decoding location to find the actual DCI. If there are X (e.g., 42) blind decodings per time slot, the UE can find the DCI on average after (X / 2) of these decodings. Some UE types (e.g., RedCap) are more sensitive to power consumption.

[0021] Monitoring PDCCH candidates in the search space and searching for them to find DCI can lead to high UE power consumption. Traditional techniques for reducing power consumption during PDCCH candidate monitoring rely on reducing the monitoring period or the number of PDCCH candidates to be monitored. However, reducing the monitoring period or the number of PDCCH candidates has been shown to be suboptimal. For example, reducing the number of PDCCH candidates increases the likelihood of overlap between two PDCCHs used by two different UEs, potentially increasing the risk of blocking. Furthermore, the gain from reducing PDCCH monitoring is relatively small. Therefore, techniques for reducing power consumption during monitoring are needed.

[0022] Figure 1 An example wireless communication system 100 is illustrated. In some cases, system 100 can be implemented to monitor the PDCCH search space. A UE can monitor the PDCCH search space and search the search space to find its DCI. As shown, example system 100 includes a base station 110 with a coverage area 101. Base station 110 serves multiple UEs, including UE 120. Transmissions from base station 110 to UE 120 are referred to as downlink (DL) transmissions and occur on the downlink channel (…). Figure 1 The transmission from UE 120 to base station 110 is called uplink (UL) transmission and occurs on the uplink channel (shown as a solid arrow). Figure 1(Seen as a dashed arrow in the diagram). Data carried over the uplink / downlink connection can include data transmitted between UEs 120 and data transmitted to and from a remote end (not shown) via the backhaul network 130. Example uplink channels and signals include the Physical Uplink Shared Channel (PUSCH), the Physical Uplink Control Channel (PUCCH), the Sounding Reference Signal (SRS), or the Physical Random Access Channel (PRACH). Service can be provided to multiple UEs 120 by a service provider (not shown) connected to base station 110 via the backhaul network 130, such as the Internet.

[0023] In some cases, the ordering of PDCCH candidates in the search space can be defined in example system 100. Both the base station (e.g., base station 110) and the UE (e.g., UE 120) are aware of the ordering of the PDCCH candidates. The UE can follow this ordering to search for PDCCH candidates to find a DCI intended for use by the UE. In some cases, the UE does not expect to detect more than one DCI while monitoring the same PDCCH. In some cases, the preferred location of a candidate in the search space can be known to both the base station and the UE, and can be searched by the UE with a higher priority than other locations. Therefore, compared to methods requiring the UE to traverse a long candidate list, a DCI intended for use by the UE can be found faster, thereby reducing power consumption.

[0024] Turning to a more general description of the elements in the specification, the term "base station" refers to any component (or collection of components) configured to provide wireless access to a network. A base station may also be referred to as a NodeB, Evolved NodeB (eNB), Next Generation (NG) NodeB (gNB), Master eNB (MeNB), Secondary eNB (SeNB), Master gNB (MgNB), Secondary gNB (SgNB), Network Controller, Control Node, Access Node, Access Point, Transmission Point (TP), Transmission-Reception Point (TRP), Cell, Carrier, Macrocell, Femtocell, Picocell, Repeater, Customer Premises Equipment (CPE), Network Side, Network, etc.

[0025] As used herein, the term "UE" refers to any component (or collection of components) capable of establishing a wireless connection with a base station. UEs may also be referred to as mobile stations, mobile devices, handsets, terminals, user terminals, users, subscribers, sites, communication equipment, CPEs, repeaters, integrated access and backhaul (IAB) repeaters, etc. It should be noted that when using repeaters (based on repeaters, picocells, CPEs, etc.), especially multi-hop repeaters, the boundary between the controller and the nodes controlled by that controller may become blurred, and dual-node deployments (e.g., the controller or the nodes controlled by that controller) may be implemented, where the first node providing configuration or control information to the second node is considered the controller. Similarly, the concepts of UL and DL transmissions can be extended.

[0026] A cell may include one or more bandwidth parts (BWPs) for a UL or DL ​​allocated to the UE. Each BWP may have its own BWP-specific parameter set (numerology) and configuration, such as the BWP's bandwidth. It should be noted that not all BWPs need to be active simultaneously for the UE. A cell may correspond to one carrier, and in some cases, multiple carriers. In some cases, a cell (e.g., a primary cell (PCell) or a secondary cell (SCell)) is a component carrier (e.g., a primary component carrier (PCC) or a secondary CC (SCC)). For some cells, each cell may include multiple carriers in the uplink, one carrier referred to as a UL carrier or non-supplementary UL (non-SUL) (or UL-only) carrier with an associated DL, while other carriers are referred to as supplementary UL (SUL) carriers without an associated DL. A cell or carrier can be configured with a time slot or subframe format including DL symbols and UL symbols, and the cell or carrier is considered to operate in time division duplex (TDD) mode. Generally, for unpaired spectrum, the cell or carrier is in TDD mode, while for paired spectrum, the cell or carrier is in frequency division duplex (FDD) mode. The transmission time interval (TTI) typically corresponds to a subframe (e.g., in LTE) or a time slot (e.g., in NR). Access nodes can provide radio access according to one or more wireless communication protocols, such as Long Term Evolution (LTE), LTE Advanced (LTE-A), 5G, 5G LTE, 5G NR, future 5G NR versions, 6G, High Speed ​​Packet Access (HSPA), Wi-Fi 802.11a / b / g / n / ac, etc. While it is understood that a communication system can employ multiple access nodes (or base stations) capable of communicating with multiple UEs, for simplicity, Figure 1 Only one access point and two UEs are shown in the image.

[0027] Although Figures 1 to 7The elements are shown as various components, parts, or modules that implement various features and functions; however, these elements may alternatively include multiple submodules, third-party services, components, libraries, etc., as needed. Furthermore, the features and functions of various components can be combined into fewer components as required.

[0028] In some cases, PDCCH candidates in the PDCCH search space are organized in a specific way. Figure 2 An example arrangement of PDCCH candidates in the search space is shown. Figure 2 In the example shown, PDCCH candidates can be listed as (a, b), where "a" represents the candidate index and "b" represents the aggregation level. In this example, the number of PDCCH candidates for aggregation levels 1, 2, 4, 8, and 16 are 8, 8, 4, 4, and 2, respectively. As shown, the PDCCH candidates for aggregation level 1 include PDCCH candidates (0, 1), (1, 1), (2, 1), (3, 1), (4, 1), (5, 1), (6, 1), (7, 1), and (8, 1), and the PDCCH candidates for aggregation level 16 include candidates (0, 16) and (1, 16). Figure 2 The left column represents the control channel element (CCE) indices. As shown, for aggregation level 1, each PDCCH candidate has one CCE index. For example, candidate (0, 1) has index CCE0, and candidate (1, 1) has index CCE1. For aggregation levels 2, 4, or 8, each PDCCH candidate has more than one CCE index. For example, candidate (0, 2) has two indices, CCE0 and CCE1. Candidate (0, 8) has eight indices, CCE0 through CCE7.

[0029] Figure 3 A flowchart illustrating an example process 300 for monitoring the PDCCH search space is shown. In some cases, process 300 may be implemented by a UE in a wireless communication system (e.g., UE 120 in system 100). In other cases, process 300 may be implemented by any suitable device. Generally, a ranking of PDCCH candidates is defined, and the UE traverses the PDCCH candidates sequentially based on the defined ranking until the UE finds a PDCCH candidate with a DCI intended for use by the UE, or until the UE has checked all PDCCH candidates.

[0030] At step 302, the UE (e.g., UE 120) determines a candidate order number for each of the multiple PDCCH candidates in the predetermined search space. The candidate order number may be determined based on one or more factors such as aggregation level or candidate index. The determination of the candidate order number will be described in detail below.

[0031] After determining the candidate sequence number, the UE determines the first candidate to be inspected among multiple PDCCH candidates based on the candidate sequence number. In some cases, the UE sets a candidate counter that indicates the candidate sequence number of the PDCCH candidate to be inspected. In some cases, the UE may determine to start with the first PDCCH candidate with the smallest candidate sequence number (e.g., 0) and set the candidate counter i to 0 (step 304). The UE attempts to decode the PDCCH candidate corresponding to the value indicated by the candidate counter (step 306) and determines whether the DCI is found in the decoded PDCCH candidate (step 308).

[0032] If a DCI is found in the decoded PDCCH candidate, the UE continues processing the DCI (step 310). If no DCI is found in the decoded PDCCH candidate, the UE increments the candidate counter by, for example, 1 (step 312) and determines whether all candidates have been checked (step 314). In one example, the UE can determine whether all candidates have been checked by determining whether the value indicated by the candidate counter has reached a predetermined threshold for the number of PDCCH candidates. If the UE determines that no PDCCH was found in the most recently checked PDCCH candidate and that all PDCCH candidates have been checked, the UE can determine that no DCI was found in the search space (step 316). If the UE determines that there are still candidates to be checked in the search space, the UE can continue decoding the next PDCCH candidate based on the candidate order number. In one example, the UE can continue checking PDCCH candidates with candidate order numbers that match the current value indicated by the candidate counter.

[0033] In some cases, the order of PDCCH candidates is known to both the base station and the UE, so that both the base station and the UE know the order in which to traverse the PDCCH candidates.

[0034] In some cases, the ordering of PDCCH candidates can be determined based on the candidate index. For each search space, the candidate index can be limited based on the Control Channel Element (CCE) index as follows.

[0035] For the search space set s associated with CORESET p, in the context of the carrier indication field value n CI The corresponding serving cell's activation DL BWP time slot In the search space set of PDCCH candidates The CCE index corresponding to aggregation level L is given by the following formula:

[0036]

[0037] in,

[0038] For any CSS,

[0039] For USS, Y p,-1 =n RNTI ≠0; for pmod3=0, A p =39827; For pmod3=1, A p =39829; For pmod3=2, A p =39839; and D=65537;

[0040] i = 0, ..., L-1;

[0041] N CCE,p This refers to the number of CCEs in CORESET p, numbered from 0 to N. CCE,p -1, and based on a set of resource blocks (RBs) (if they exist);

[0042] If the UE is configured with a carrier indication field via CrossCarrierSchedulingConfig for the serving cell on which the PDCCH is monitored, then n CI It is the carrier indicator field value; otherwise, including for any CSS, n CI =0;

[0043] in, The UE is configured to monitor n CI The number of PDCCH candidates at the aggregation level L of the search space set s of the corresponding serving cell.

[0044] The CCE index depends on the C-RNTI and is therefore UE-specific. In some cases, the CCE index can be used "as is" to determine the order of PDCCH candidates. In some cases, the UE can start with the smallest CCE index value among the PDCCH candidates (e.g., 0). In one example and referring to... Figure 2 The UE can start with CCE0 from candidate (0, 1). In another example and referring to... Figure 2 The UE can start with CCE16 from candidate (2, 4). In some cases, each candidate can have an index predefined in the technical specification (e.g., TS 38.213). This index can be used for ordering PDCCH candidates. In some examples, the UE can start with the candidate with the smallest index value (e.g., 0).

[0045] In some cases, a predetermined index value can be used to determine where to begin monitoring the PDCCH search space. In other cases, parameter U can be signaled to the UE (e.g., via RRC configuration). The UE can then select candidates for aggregation level L. To begin. In the case of a common search space and without UE-specific parameters, PDCCH candidates can have the same index for all UEs (as specified in TS38.213). Using UE-specific parameters to determine the first candidate ensures that each UE has a different starting point.

[0046] In some cases, preferred locations for candidates in the search space can be indicated to the base station and the UE, and can be searched by the UE with higher priority than other locations. In some cases, the preferred location can indicate the target aggregation level (e.g., aggregation level 8, 4, 2, or 1). In one example, the UE can start by checking PDCCH candidates in the search space from the target aggregation level 8.

[0047] In some cases, a preferred location can indicate a preferred CCE index. In some examples, the target aggregation level can be associated with a predefined number of CCEs, and the preferred CCE index can be different for different aggregation levels.

[0048] In some cases, the preferred CCE index and target aggregation level can be used in combination to determine the candidate ranking. The UE can start traversing the candidates in the first time slot using the target aggregation level and the preferred CCE index. For the remaining time slots, the UE can start in the second time slot with the same target aggregation level and the same preferred CCE index as when it started searching for the DCI.

[0049] Figure 4 A flowchart illustrating an example process 400 for monitoring the PDCCH search space based on aggregation levels is shown. In some cases, process 400 can be implemented by a UE in a wireless communication system (e.g., UE 120 in system 100). In other cases, process 400 can be implemented by any suitable device. Generally, the UE can be configured with one or more target aggregation levels (ALs) that assist the UE in using target ALs as preferred ALs to search for DCIs in the search space. If a DCI is found, the UE stops searching.

[0050] At step 402, the UE (e.g., UE 120) is configured with one or more target ALs and one or more CCE candidates for each target AL. In some cases, and as described herein, CCE candidates indicate where the UE can find a CCE location intended for use with the UE's PDCCH / DCI. Each CCE candidate is associated with a CCE index. In one example, the UE may be configured with two target ALs and use both target ALs as preferred ALs. In this example, if no DCI is found for the first target AL, the UE may continue searching for a DCI using the second target AL. If no DCI is found for the second target AL either, the UE may continue looking at other ALs.

[0051] In some cases, each target AL in the target AL is associated with an AL index number, and each CCE candidate in the CCE candidates is associated with a CCE candidate number. The UE can set a target AL counter that indicates the AL index number of the target AL to be examined. The UE can set a CCE candidate counter that indicates the CCE candidate number of the CCE candidate to be examined. The UE can use the target AL counter and the CCE candidate counter to examine candidates in the search space.

[0052] In some cases, the UE may determine a first target AL with the smallest AL index number (e.g., 1) among one or more target ALs and set the target AL counter to 1 (j=1) (step 404). After determining the first target AL, the UE may determine a first CCE candidate with the smallest CCE candidate number (e.g., 0) among one or more CCE candidates for the first target AL and set the CCE candidate counter to 0 (i=0) (step 406).

[0053] After identifying the first CCE candidate for the first target AL, the UE decodes the first CCE candidate (step 408) and determines whether a DCI is found in the first CCE candidate (step 410). If a DCI is found in the first CCE candidate, the UE continues processing the DCI (step 412). If no DCI is found in the first CCE candidate, the UE increments the CCE candidate counter by, for example, 1 (step 414) and determines whether all CCE candidates for the first target AL have been checked (step 416). In this example, the UE may determine whether the CCE candidate counter has reached a predetermined threshold. If the UE determines that not all candidates have been checked and there are still remaining CCE candidates to be checked for the first target AL, the UE continues to check the next CCE candidate in the first target AL. If the UE has checked all CCE candidates for the first target AL, the UE determines that no DCI is found in the search space for the first target AL (418) and continues to check the second target AL to find a DCI (step 420), which includes repeating steps 404 to 418 for the second target AL.

[0054] In some cases, the UE can monitor the PDCCH search space based on the estimated signal-to-interference-plus-noise ratio (SINR), starting from a certain aggregation level. In one example, the UE might attempt to find candidates based on the aggregation level corresponding to the radio conditions (e.g., a UE operating at 0 dB SINR is unlikely to use aggregation level 1). In some cases, a lookup table can be defined to indicate which aggregation level to monitor. Table 1 is an example lookup table illustrating the correspondence between SINR and the aggregation level to be monitored.

[0055] Table 1

[0056] SINR The first thing to monitor is the aggregation level. SINR <T0 16 T0≤SINR<T1 8 T1≤SINR<T2 4 T2≤SINR<T3 2 T3≤SINR<T4 1

[0057] Parameters T0, T1, T2, T3, and T4 need to be known at both the base station and the UE. These parameters largely depend on the base station's transmission parameters and the UE's reception parameters (e.g., the number of antennas). Therefore, these parameters should be link-specific. Several methods exist for obtaining these parameters: (1) via RRC signaling (dedicated or public RRC signaling) sent from the base station to the UE; (2) based on UE characteristics (capabilities); (3) based on hard-coded values ​​specified in standard specifications; or (4) based on measurements used to determine the aggregation level, which can be any indicator related to radio conditions, such as RSRP (reference signal receiving power), RSRQ (reference signal receiving quality), RSSI (received signal strength indication), SNR (signal-to-noise-ratio), SINR, etc.

[0058] Figure 5 A flowchart illustrating an example process 500 for monitoring the PDCCH search space based on estimated SINR is shown. In some cases, process 500 can be implemented by a UE in a wireless communication system (e.g., UE 120 in system 100). In other cases, process 500 can be implemented by any suitable device.

[0059] At step 502, the UE (e.g., UE 120) estimates the SINR and determines a first target AL based on the estimated SINR. In some cases, the UE may store a lookup table (e.g., Table 1) indicating the correspondence between multiple SINR ranges and multiple target aggregation levels. In one example, the lookup table may indicate that the UE may first target a higher AL for a lower SINR. The UE may determine the first target AL based on the estimated SINR and the lookup table.

[0060] After determining the first target AL, the UE determines the first PDCCH candidate to search the DCI (step 504). In some examples, the UE may determine the first PDCCH candidate based on the index number of the PDCCH candidate for the first target AL. The UE may determine the first PDCCH candidate as the PDCCH candidate with the smallest index number (e.g., index number i = 0). In some cases, the UE may set a candidate counter to indicate the number of PDCCH candidates that have been checked.

[0061] The UE decodes the first PDCCH candidate (step 506) and determines whether the first PDCCH candidate includes a DCI for the UE (step 508). If a DCI is found in the first PDCCH candidate, the UE continues processing the DCI (step 510).

[0062] If no DCI is found in the first PDCCH candidate, the UE continues searching the next PDCCH for the DCI. In one example, the UE may search for a second PDCCH candidate with the second smallest index number (e.g., index number i = 1). The UE may update the candidate counter, for example, by incrementing the candidate counter by 1 (step 512). The UE then determines whether all candidates have been checked for the first target AL (step 514). In one example, the UE may determine whether all candidates have been checked by determining whether the candidate counter value has reached a predetermined threshold for the number of candidates for the target AL. If the UE determines that all candidates have now been checked and there are still remaining candidates to be checked for the target AL, the UE continues checking the next PDCCH based on the updated candidate counter. If the UE determines that all candidates have been checked for the first target AL and no DCI has been found, the UE determines that no DCI has been found in the search space for the first target AL (step 516). The UE then continues checking the AL closest to the first target AL in the lookup table (step 518). In one example, if the first target AL is AL 8, the second target AL could be AL 4. In some cases, the UE resets the candidate counter before continuing to check candidates for the next AL. In some cases, if no DCI is found for the second AL closest to the first target AL, the UE can continue checking with the AL closest to the second AL. Alternatively, in some cases, if no DCI is found for the second AL closest to the first target AL, the UE can check the remaining candidates in any suitable order.

[0063] In some cases, when the UE acquires a PDCCH in an earlier time slot, the UE can maintain tracking of the aggregation level and candidate number. For future PDCCH searches, the UE can begin its search with the aggregation level and candidate order of the previous successful PDCCH decoding attempt. Alternatively, in some cases, the UE can begin with only the aggregation level of the previous decoded PDCCH.

[0064] Figure 6 A flowchart illustrating an example process 600 for monitoring the PDCCH search space is shown. In some cases, process 600 may be implemented by a UE in a wireless communication system (e.g., UE 120 in system 100). In other cases, process 600 may be implemented by any suitable device.

[0065] At step 602, the UE (e.g., UE 120) receives an indication or signaling for determining the PDCCH candidate ordering for multiple PDCCH candidates in the PDCCH search space. In some cases, the indication includes at least one of the following: a target aggregation level, a starting CCE index among multiple CCE indices for the PDCCH search space, or a UE-specific parameter. In some cases, the indication is sent in an RRC configuration from a base station (e.g., base station 110). The information in the indication may be determined based on an estimate of the signal-to-interference-plus-noise ratio (SINR) by the UE. In one example, the indication may include a target aggregation level determined based on a lookup table (e.g., Table 1) and the estimated SINR. In some cases, the PDCCH candidate ordering indicates the preferred position of the PDCCH candidates in the PDCCH search space (e.g., a target aggregation level or CCE index), and each PDCCH candidate is associated with one or more CCE indices. The information in the indication may include preferred positions of the PDCCH candidates predefined in the technical specifications.

[0066] At step 604, the UE determines a first PDCCH candidate from a plurality of PDCCH candidates based on the indication. In some cases, the UE determines an index number for each of the plurality of PDCCH candidates. The UE continues to determine the first PDCCH candidate based on this index number. In one example, the first PDCCH candidate is determined based on the index number of each PDCCH candidate, wherein the first PDCCH candidate has the smallest index number among the plurality of PDCCH candidates.

[0067] In some cases, the UE determines the first PDCCH candidate based on at least one of the aggregation level order and the control channel element (CCE) order. In some cases, the UE receives radio resource control (RRC) parameters from the base station, where the RRC parameters indicate one or more target aggregation levels. These one or more target aggregation levels are the aggregation levels the UE should use first to examine the candidate. In some cases, the UE determines the first PDCCH candidate based on the order of one or more target aggregation levels. In some cases, the UE can begin examining the candidate from the target aggregation level with the highest order among one or more target aggregation levels. In one example, the UE can determine to begin examining from AL order 16 among AL orders 16, 8, 4, 2, and 1.

[0068] In some cases, the UE determines the estimated signal-to-interference-plus-noise ratio (SINR). The target aggregation level is determined by the UE based on a predetermined mapping between multiple estimated SINRs and multiple target aggregation levels. The UE determines the first PDCCH candidate at the target aggregation level.

[0069] After determining the first PDCCH candidate, the UE continues to determine whether a DCI for the UE is found in the first PDCCH candidate. At step 606, the UE determines that no DCI for the UE is found in the first PDCCH candidate. In response to determining that no DCI for the UE is found in the first PDCCH candidate, the UE determines a second PDCCH candidate from a plurality of PDCCH candidates based on an indication (step 608). In some cases, the second PDCCH candidate has a second index number that is larger than the first index number of the first PDCCH candidate. In some cases, the second PDCCH candidate among the plurality of PDCCH candidates based on the indication comes from the remaining candidates that could not be determined as the first PDCCH candidate from the plurality of PDCCH candidates based on the indication.

[0070] Then, the UE determines whether a DCI for the UE is found in the second PDCCH candidate. At step 610, the UE determines that a DCI for the UE is found in the second PDCCH candidate. Then, in response to determining that a DCI for the UE is found in the second PDCCH candidate, the UE continues to process the DCI (step 612). If no DCI is found in the second PDCCH candidate, the UE continues to check the remaining PDCCH candidates based on the PDCCH candidate sorting until a DCI is found or all candidates have been checked.

[0071] Figure 7 This is a block diagram of an example computer system 700, implemented according to a specific method, for providing computational functionality associated with the algorithms, methods, functions, processes, flows, and procedures described herein. One or more computer systems 700 can be used to implement electronic devices previously described in this disclosure, such as UEs, eNBs, gNBs, or other network nodes. In some cases, computer system 700 can be implemented as... Figure 1 Either UE 120 or base station 110.

[0072] In some aspects, computer system 700 may include a computer that includes: input devices, such as a keypad, keyboard, touchscreen, or other devices that can accept user information; and output devices that transmit information associated with the operation of computer system 700, including digital data, visual or audio information (or a combination of information), or a graphical user interface (GUI).

[0073] Computer system 700 can act as a client, network component, server, database or other persistent device, or any other component (or combination of roles) of a computer system for performing the subject matter described herein. In some implementations, one or more components of computer system 700 may be configured to operate within an environment based on cloud computing, local, global, or other environments (or combinations thereof).

[0074] At a higher level, computer system 700 is an electronic computing device capable of receiving, sending, processing, storing, or managing data and information associated with the described subject. Depending on some implementations, computer system 700 may also include an application server, email server, web server, cache server, streaming data server, or other servers (or combinations thereof), or be communicatively coupled to such servers.

[0075] Computer system 700 can receive requests from client applications via a network and respond to the received requests by processing them using appropriate software applications. Additionally, requests can also be sent to computer system 700 from internal users (e.g., from a command console or other suitable access methods), external or third parties, other automated applications, and any other suitable entity, individual, system, or computer.

[0076] Computer system 700 includes interface 702. Although in Figure 7 While shown as a single interface 702, two or more interfaces 702 may be used depending on the specific needs, expectations, or particular implementation of the computer system 700. Interface 702 is used by the computer system 700 to communicate with other systems connected to a network (whether shown or not) in a distributed environment. Typically, interface 702 includes logic encoded in software or hardware (or a combination of software and hardware) and is operable for communicating with the network. More specifically, interface 702 may include software supporting one or more communication protocols associated with the communication, enabling the interface hardware to operate for transmitting physical signals both inside and outside the illustrated computer system 700.

[0077] Computer system 700 includes processor 704. Although in Figure 7 The computer system 700 is shown as a single processor 704, but two or more processors may be used depending on the specific requirements, expectations, or particular implementation of the computer system 700. Typically, the processor 704 executes instructions and manipulates data to perform the operations of the computer system 700 and any algorithms, methods, functions, processes, flows, and procedures as described in this disclosure.

[0078] Computer system 700 also includes memory 706, which can store data for computer system 700 or other components (or combinations thereof) that can be connected to a network (whether shown or not). For example, memory 706 can be random access memory (RAM), read-only memory (ROM), optical devices, magnetic devices, etc., to store data consistent with this disclosure. In some implementations, memory 706 can be a combination of two or more different types of memory (e.g., a combination of RAM and magnetic storage devices) depending on the specific needs, expectations, or particular implementation and functions described for computer system 700. Although in Figure 7 The memory 706 is shown as a single memory, but two or more memories 706 (of the same or combined types) may be used depending on the specific needs, expectations, or particular implementation and described functionality of the computer system 700. Although the memory 706 is shown as an integral part of the computer system 700, in alternative implementations, the memory 706 may be external to the computer system 700.

[0079] Application 708 is an algorithmic software engine that provides functionality, particularly the functionality described herein, according to the specific needs, expectations, or implementation of computer system 700. For example, application 708 can be used as one or more components, modules, or applications. Furthermore, although shown as a single application 708, application 708 can be implemented as multiple applications 708 on computer system 700. Additionally, although shown as an integral part of computer system 700, in alternative implementations, application 708 can be external to computer system 700.

[0080] Any number of computer systems 700 may exist, associated with or external to the computer system containing the computer systems 700, each communicating via a network. Furthermore, the terms "client," "user," and other suitable terms may be used interchangeably as needed without departing from the scope of this disclosure. Moreover, this disclosure envisions a plurality of users using one computer system 700, or a single user using multiple computer systems 700.

[0081] The subject matter and functional operations described in this specification can be implemented in digital electronic circuits, in tangibly embodied computer software or firmware, in computer hardware including the structures disclosed in this specification and their equivalents, or one or more combinations thereof. The subject matter described in this specification can be implemented as one or more computer programs, i.e., one or more modules of computer program instructions encoded in a tangible, non-transitory, computer-readable computer storage medium for execution by a data processing device or to control the operation of a data processing device. Alternatively or additionally, the program instructions can be encoded in / on artificially generated propagation signals, such as machine-generated electrical, optical, or electromagnetic signals, which are generated to encode information for transmission to a suitable receiver device for execution by the data processing device. The computer storage medium can be a machine-readable storage device, a machine-readable storage substrate, a random or serial access memory device, or a combination of computer storage media.

[0082] The terms "data processing apparatus," "computer," or "electronic computer equipment" (or equivalents as understood by one of ordinary skill in the art) refer to data processing hardware and encompass various means, devices, and machines for processing data, including, for example, programmable processors, computers, or multiple processors or computers. The apparatus may also be or include special-purpose logic circuitry, such as a central processing unit (CPU), a field-programmable gate array (FPGA), or an application-specific integrated circuit (ASIC). In some implementations, the data processing apparatus or special-purpose logic circuitry (or a combination thereof) may be hardware-based or software-based (or a combination of both). The apparatus may optionally include code that creates an execution environment for computer programs, such as code constituting a combination of processor firmware, protocol stack, database management system, operating system, or execution environment. This disclosure contemplates data processing apparatuses with or without a conventional operating system, such as LINUX, UNIX, WINDOWS, MAC OS, ANDROID, IOS, or any other suitable conventional operating system.

[0083] A computer program may also be referred to or described as a program, software, software application, module, software module, script, or code. A computer program can be written in any programming language, including compiled or interpreted languages, declarative languages, or procedural languages, and can be deployed in any form, including as a standalone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program may, but does not need to, correspond to a file in a file system. A program may be stored as a part of a file containing other programs or data (e.g., stored in one or more scripts in a markup language document), may be stored in a single file dedicated to the program in question, or may be stored in multiple collaborative files (e.g., a file storing one or more modules, subroutines, or portions of code). A computer program may be deployed to execute on a single computer, or on multiple computers located at a single site or distributed across multiple sites and interconnected via a communication network. While the various parts of the program shown in the various figures are depicted as separate modules implementing various features and functions through various objects, methods, or other processes, the program may alternatively include multiple submodules, third-party services, components, libraries, etc., as needed. Conversely, the features and functions of various components may be combined into a single component as needed. The threshold used for calculation can be determined statically, dynamically, or both.

[0084] The methods, processes, and logic flows described herein can be performed by one or more programmable computers that execute one or more computer programs to perform functions, by manipulating input data and generating output. The methods, processes, or logic flows can also be performed by dedicated logic circuitry, and the apparatus can also be implemented as dedicated logic circuitry, such as a CPU, FPGA, or ASIC.

[0085] A computer suitable for executing computer programs can be based on a general-purpose microprocessor or a special-purpose microprocessor, both, or any other type of CPU. Typically, the CPU receives instructions and data from ROM or random access memory (RAM), or both ROM and RAM. The basic components of a computer are the CPU for running or executing instructions and one or more storage devices for storing instructions and data. Typically, a computer will also include or be operatively coupled to one or more mass storage devices such as disks, magneto-optical disks, or optical disks for storing data, to receive data from and / or transfer data to them, or both. However, a computer does not necessarily need to have such devices. Furthermore, a computer can be embedded in another device, such as a mobile phone, a personal digital assistant (PDA), a mobile audio or video player, a game console, a Global Positioning System (GPS) receiver, or a portable storage device such as a Universal Serial Bus (USB) flash drive, etc.

[0086] Computer-readable media suitable for storing computer program instructions and data (transitory or non-transitory as needed) include non-volatile memory, media, and storage devices, including, for example, semiconductor storage devices such as erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), and flash memory devices; disks such as internal hard disks or removable disks; magneto-optical disks; and CD-ROM, DVD+ / –R, DVD-RAM, and DVD-ROM disks. Memory can store a variety of objects or data, including caches, categories, frames, applications, backup data, tasks, web pages, web page templates, database tables, repositories storing dynamic information, and any other suitable information including any parameters, variables, algorithms, instructions, rules, constraints, or references thereof. Additionally, memory may include any other suitable data, such as logs, policies, security or access data, report files, and other data. Processors and memory may be supplemented by or incorporated into dedicated logic circuitry.

[0087] To provide user interaction, the implementations of the subject matter described in this specification can be implemented on a computer having a display device for displaying information to the user, such as a cathode ray tube (CRT), liquid crystal display (LCD), light emitting diode (LED), or plasma detector, and a keyboard and pointing device, such as a mouse, trackball, or trackpad, through which the user can provide input to the computer. Input can also be provided to the computer using a touchscreen, such as a pressure-sensitive tablet surface, a capacitive or electrosensitive multi-touch screen, or other types of touchscreen. Other types of devices can also be used to provide user interaction: for example, feedback provided to the user can be any form of sensory feedback, such as visual, auditory, or tactile feedback; and input from the user can be received in any form, including auditory, voice, or tactile input. Additionally, the computer can interact with the user by sending and receiving documents to and from the user's device, for example, by sending a webpage to a web browser on the user's client device in response to a request received from a web browser.

[0088] The implementation of the subject matter described in this specification can be implemented in a computing system that includes backend components, such as a data server; or middleware components, such as an application server; or frontend components, such as a client computer with a graphical user interface or a web browser through which a user can interact with the implementation of the subject matter described in this specification; or any combination of one or more such backend components, middleware components, or frontend components. The components of the system can be interconnected via any form or medium of wired or wireless digital data communication (or a combination of data communications), such as a communication network. Examples of communication networks include local area networks (LANs), radio access networks (RANs), metropolitan area networks (MANs), wide area networks (WANs), worldwide interoperability for microwave access (WIMAX), wireless local area networks (WLANs) using, for example, 802.11a / b / g / n or 802.20 (or combinations of 802.11x and 802.20 or other protocols consistent with this disclosure), all or part of the Internet, or any other communication system (or combination of communication networks) located in one or more locations. The network may communicate, for example, with Internet Protocol (IP) packets, Frame Relay frames, Asynchronous Transfer Mode (ATM) cells, voice, video, data, or other suitable information (or combinations of communication types) between network addresses.

[0089] A computing system may include clients and servers. Clients and servers are typically geographically separated and usually interact through a communication network. The client-server relationship is established through computer programs running on their respective computers that have a client-server relationship with each other.

[0090] While this specification contains numerous specific implementation details, these details should not be construed as limiting the scope of any invention or the scope of what may be claimed, but rather as descriptions of features specific to particular implementations of a particular invention. Certain features described in the context of separate implementations may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented individually or in any suitable sub-combination in multiple implementations. Furthermore, while previously described features may be described as functioning in certain combinations and even initially claimed in this way, in some cases, one or more features from the claimed combination may be removed from said combination, and the claimed combination may involve sub-combinations or variations thereof.

[0091] Specific implementations of this subject matter have been described. Other implementations, modifications, and substitutions of the described implementations are within the scope of the appended claims, as will be apparent to those skilled in the art. Although operations are described in a specific order in the drawings or claims, this should not be construed as requiring these operations to be performed in the specific order shown or in a sequential order, or requiring the performance of all shown operations (some operations may be considered optional) to achieve the desired result. In some cases, multitasking or parallel processing (or a combination of multitasking and parallel processing) may be advantageous and performed where deemed appropriate.

[0092] Furthermore, the separation or integration of the various system modules and components in the previously described implementations should not be construed as requiring such separation or integration in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

[0093] Therefore, the example implementations described above do not limit or constrain the content of this disclosure. Other changes, substitutions, and modifications may be made without departing from the spirit and scope of this disclosure.

[0094] Furthermore, any claimed implementation is considered to be at least applicable to a computer-implemented method; a non-transitory computer-readable medium storing computer-readable instructions to perform the computer-implemented method; and a computer system including computer memory interoperably coupled to a hardware processor configured to perform the computer-implemented method and instructions stored on the non-transitory computer-readable medium.

Claims

1. A computer-implemented method for monitoring the search space of the Physical Downlink Control Channel (PDCCH), the method comprising: The user equipment (UE) receives an indication for determining the PDCCH candidate ordering among multiple PDCCH candidates; The UE determines a first PDCCH candidate from the plurality of PDCCH candidates based on the indication; The UE determines that no downlink control information (DCI) for the UE is found in the first PDCCH candidate; In response to determining that no DCI for the UE is found in the first PDCCH candidate, the UE determines a second PDCCH candidate from the plurality of PDCCH candidates based on the indication; The UE determines that a DCI for the UE is found in the second PDCCH candidate; as well as In response to determining that a DCI for the UE is found in the second PDCCH candidate, the DCI is processed.

2. The computer-implemented method according to claim 1, wherein, The instruction is based on one of the following: RRC configuration sent by the base station; The UE's estimation of the signal-to-interference-plus-noise ratio (SINR); or The instructions are predefined in the specification.

3. The computer-implemented method according to claim 1, wherein, The PDCCH candidate ordering indicates the preferred position of the PDCCH candidate in the PDCCH search space, and each of the plurality of PDCCH candidates is associated with one or more Control Channel Element (CCE) indices.

4. The computer-implemented method according to claim 1, wherein, The instruction includes at least one of the following: Target aggregation level; For the starting CCE index among multiple CCE indices in the PDCCH search space; or Parameters specific to the UE.

5. The computer-implemented method according to claim 1, wherein, The UE determines the first PDCCH candidate from the plurality of PDCCH candidates based on the indication, including: The UE determines the index number of each PDCCH candidate among the plurality of PDCCH candidates; and The UE determines the first PDCCH candidate based on the index number of each PDCCH candidate, wherein the first PDCCH candidate has the smallest index number among the plurality of PDCCH candidates.

6. The computer-implemented method according to claim 5, wherein, The UE determines the second PDCCH candidate from the plurality of PDCCH candidates based on the indication, including: The UE determines the second PDCCH candidate based on the index number of each PDCCH candidate, wherein the second PDCCH candidate has a second index number that is larger than the first index number of the first PDCCH candidate.

7. The computer-implemented method according to claim 1, wherein, The UE determines the first PDCCH candidate from the plurality of PDCCH candidates based on the indication, including: The first PDCCH candidate is determined based on at least one of the aggregation level order or the control channel element CCE order.

8. The computer-implemented method according to claim 1, further comprising: The UE receives Radio Resource Control (RRC) parameters from the base station, the RRC parameters indicating one or more target aggregation levels.

9. The computer-implemented method according to claim 8, wherein, The UE determines the first PDCCH candidate from the plurality of PDCCH candidates based on the indication, including: The first PDCCH candidate is determined by the UE based on the sorting of one or more target aggregation levels.

10. The computer-implemented method according to claim 1, wherein, The UE determines the first PDCCH candidate from the plurality of PDCCH candidates based on the indication, including: The estimated signal-to-interference-plus-noise ratio (SINR) is determined by the UE. The target aggregation level is determined by the UE based on a predetermined mapping relationship between multiple estimated SINRs and multiple target aggregation levels; and The UE determines the first PDCCH candidate under the target aggregation level.

11. An electronic device, comprising: At least one processor; as well as One or more memories coupled to the at least one processor and storing program instructions for execution by the at least one processor to: Receive an instruction for determining the PDCCH candidate ordering for multiple PDCCH candidates in the PDCCH search space; A first PDCCH candidate is determined from the plurality of PDCCH candidates based on the indication; It was determined that no downlink control information (DCI) for the user equipment (UE) was found in the first PDCCH candidate. In response to determining that no DCI for the UE is found in the first PDCCH candidate, a second PDCCH candidate is determined from the plurality of PDCCH candidates based on the indication; Determine if a DCI for the UE is found in the second PDCCH candidate; as well as In response to determining that a DCI for the UE is found in the second PDCCH candidate, the DCI is processed.

12. The electronic device according to claim 11, wherein, The instruction is based on one of the following: RRC configuration sent by the base station; The UE's estimation of the signal-to-interference-plus-noise ratio (SINR); or The instructions are predefined in the specification.

13. The electronic device according to claim 11, wherein, The PDCCH candidate ordering indicates the preferred position of the PDCCH candidate in the PDCCH search space, and each of the plurality of PDCCH candidates is associated with one or more Control Channel Element (CCE) indices.

14. The electronic device according to claim 11, wherein, The instruction includes at least one of the following: Target aggregation level; For the starting CCE index among multiple CCE indices in the PDCCH search space; or Parameters specific to the UE.

15. The electronic device according to claim 11, wherein, Determining a first PDCCH candidate from the plurality of PDCCH candidates based on the indication includes: Determine the index number of each PDCCH candidate among the plurality of PDCCH candidates; and The first PDCCH candidate is determined based on the index code of each PDCCH candidate, wherein the first PDCCH candidate has the smallest index number among the plurality of PDCCH candidates.

16. A non-transitory computer-readable medium storing program instructions for execution by at least one processor to: Receive an instruction for determining the PDCCH candidate ordering for multiple PDCCH candidates in the PDCCH search space; A first PDCCH candidate is determined from the plurality of PDCCH candidates based on the indication; It was determined that no downlink control information (DCI) for the user equipment (UE) was found in the first PDCCH candidate. In response to determining that no DCI for the UE is found in the first PDCCH candidate, a second PDCCH candidate is determined from the plurality of PDCCH candidates based on the indication; Determine if a DCI for the UE is found in the second PDCCH candidate; as well as In response to determining that a DCI for the UE is found in the second PDCCH candidate, the DCI is processed.

17. The non-transitory computer-readable medium according to claim 16, wherein, The instruction is based on one of the following: RRC configuration sent by the base station; The UE's estimation of the signal-to-interference-plus-noise ratio (SINR); or The instructions are predefined in the specification.

18. The non-transitory computer-readable medium according to claim 16, wherein, The PDCCH candidate ordering indicates the preferred position of the PDCCH candidate in the PDCCH search space, and each of the plurality of PDCCH candidates is associated with one or more Control Channel Element (CCE) indices.

19. The non-transitory computer-readable medium according to claim 16, wherein, The instruction includes at least one of the following: Target aggregation level; For the starting CCE index among multiple CCE indices in the PDCCH search space; or Parameters specific to the UE.

20. The non-transitory computer-readable medium according to claim 16, wherein, Determining a first PDCCH candidate from the plurality of PDCCH candidates based on the indication includes: Determine the index number of each PDCCH candidate among the plurality of PDCCH candidates; and The first PDCCH candidate is determined based on the index code of each PDCCH candidate, wherein the first PDCCH candidate has the smallest index number among the plurality of PDCCH candidates.

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