Improved control channel element (CCE) randomization

Abstract

Methods, systems, and devices for improved control channel element (CCE) randomization are disclosed. According to one aspect, a method in a wireless device (WD) includes mapping a search space to a set of control channel elements (CCEs) when the WD supports additional non-overlapping CCEs for a given aggregation level of the CCEs. The method includes when the WD does not support additional non-overlapping CCEs, mapping the search space to a set of CCEs selected only for a search space for which a CCE aggregation level is higher than a given CCE aggregation level. The method also includes not mapping the search space otherwise.

Description

Technical Field

[0001] This disclosure relates to wireless communication, and in particular to improved control channel element (CCE) randomization. Background Technology

[0002] The 3rd Generation Partnership Project (3GPP) has developed and is developing standards for fourth-generation (4G) (also known as Long Term Evolution (LTE)) and fifth-generation (5G) (also known as New Radio (NR)) wireless communication systems. Among other features, such systems provide broadband communication between network nodes (such as base stations) and mobile wireless devices (WDs), as well as communication between network nodes and between WDs. 3GPP is also developing standards for sixth-generation (6G) wireless communication networks.

[0003] PDCCH Downlink control information (DCI) in NR consists of, for example, scheduling permissions and is transmitted on the physical downlink control channel (PDCCH). Figure 1 The diagram illustrates the overall PDCCH processing in NR. The Cyclic Redundancy Code (CRC) transmitted over the air is affected by the identity of the target device (or more generally, the Radio Network Temporary Identifier (RNTI)). Therefore, when decoding control information in a radio device's WD, information intended for another WD appears as noise to the receiver, causing the CRC check to fail and the WD to take no further action.

[0004] The PDCCH is transmitted using 1, 2, 4, 8, or 16 consecutive control channel elements (CCEs), the number of which is called the aggregation level. A control channel element is the unit that defines the search space for blind decoding, as will be discussed below. A control channel element consists of six resource element groups (REGs), each REG equal to a resource block (12 subcarriers) in an Orthogonal Frequency Division Multiplexing (OFDM) symbol. A demodulation reference signal (DM-RS) is also inserted into the PDCCH to support the channel estimation required at the WD, thus enabling decoding of the PDCCH content. After considering the DM-RS overhead, there are 54 resource elements (108 bits) available for PDCCH transmission in a single control channel element.

[0005] CORESET The core of downlink control signaling in NR is the concept of the Control Resource Set (CORESET). The Control Resource Set is a set of time-frequency resources that a device attempts to decode candidate control channels using one or more search spaces. The size and location of the CORESET in the time-frequency domain are semi-statically configured by the network and can therefore be set to be less than the carrier bandwidth.

[0006] Blind decoding and search space The WD attempts to blindly decode any PDCCH, for example, once per time slot (other time intervals are also possible). Assuming a certain payload size (with a few possible sizes) and a certain aggregation level (1, 2, 4, 8, 16 CCEs), the WD will attempt to decode candidate PDCCHs. If CRC verification succeeds, the DCI is intended for this WD, and the WD follows the DCI's content. If CRC verification fails, the content is either corrupted due to interference on the radio channel or intended for another WD. In either case, the WD will not take further action based on this (failed) decoding. See also Figure 2 .

[0007] Blind decoding represents a significant processing burden for the device, and much of the downlink control channel design is related to reducing this complexity. Two aspects of limiting blind decoding complexity are limiting the number of PDCCH candidates by restricting their positions in the time-frequency domain and disallowing arbitrary aggregation levels, and limiting the size set of DCIs to be monitored.

[0008] The CCE architecture provides a well-defined time-frequency structure that can be used to limit the number of candidates, but it is insufficient. Clearly, from a scheduling perspective, limiting the allowed aggregation levels is undesirable, as they can reduce scheduling flexibility and require additional processing on the transmitter side. Simultaneously, from a device complexity perspective, requiring the device to monitor all possible CCE aggregations and locations across all configured CORESETs is unattractive. To impose as few constraints as possible on the scheduler while limiting the maximum number of blind decoding attempts in the device, NR defines a so-called search space. The search space is the set of candidate control channels formed by CCEs at a given aggregation level, which the device should attempt to decode. Due to the existence of multiple aggregation levels, a device may have multiple search spaces. The search space set is the set of search spaces with different aggregation levels linked to the same CORESET. Therefore, by configuring the CORESET and search space set, the device can use the same time-frequency resources to monitor the presence of control channels with different aggregation levels. The purpose of different aggregation levels is to control the code rate of the PDCCH and thus enable link adaptation of the PDCCH. The higher the aggregation level, the lower the code rate for a given fixed DCI size. Therefore, under poor channel conditions, network nodes (e.g., gNBs) will choose a higher aggregation level than under favorable channel conditions.

[0009] When attempting to decode a candidate PDCCH, if a CRC check is performed and the device processes the information (scheduling assignment, scheduling authorization, etc.), the content of the control channel is declared valid for that device. If no CRC check is performed, the information is either affected by an uncorrectable transmission error or intended for another device, and in either case, the device ignores the PDCCH transmission.

[0010] Having discussed the search space, it is clear that if control information is transmitted on a PDCCH formed by the CCEs within one of the device's search spaces, then the network can only address that device. For example, Figure 3 Device A cannot address on PDCCHs starting from CCE number 20, while device B can. Furthermore, if device A is using CCEs 16 through 23, it cannot address device B at aggregation level 4 because all CCEs in its level 4 search space are blocked by other devices. Intuitively, to efficiently utilize CCEs in the system, the search spaces between devices should be different (unless all devices can monitor all CCEs, which is unlikely from a complexity perspective). Therefore, each device in the system can have one or more configured device-specific search spaces (also known as user equipment (UE)-specific search spaces, USS). Due to complexity, a device-specific search space typically cannot contain all CCEs that the network can transmit at its corresponding aggregation level; therefore, a mechanism should exist to determine the set of CCEs within the device-specific search space.

[0011] The location of a device-specific search space, represented by the starting CCE number, is defined using a function of the C-RNTI (a unique device identifier within the cell). Furthermore, the set of CCEs that a device should monitor for a given aggregation level also changes over time to avoid two devices constantly blocking each other. This randomizes the location of the search space over time (with more or less independent randomization between aggregation levels). If two search spaces collide at one time, they are less likely to collide at the next time. In each of these search spaces, the device attempts to decode the PDCCH using the device-specific C-RNTI identifier. If valid control information, such as scheduling authorization, is found, the device acts accordingly.

[0012] To limit the complexity of blind decoding in the device, NR (among others) introduces restrictions on the following aspects: Number of blind decoding attempts. For subcarrier spacing of 15 / 30 / 60 / 120 kHz, across all DCI sizes, up to 44 / 36 / 22 / 20 blind decoding attempts can be supported per slot; and The number of channel estimates. The number of channel estimates for subcarrier spacing of 15 / 30 / 60 / 120 kHz has been limited to 56 / 56 / 48 / 32 non-overlapping CCEs across all CORESETs in the time slot. Figure 3 In the example, device A must perform channel estimation for 30 non-overlapping CCEs (6-35), while device B must perform channel evaluation for 40 non-overlapping CCEs (0-39).

[0013] Depending on the configuration, the number of PDCCH candidates may be limited by the number of blind decodings or the number of channel estimates. CRC checksums are low in complexity, so monitoring multiple RNTIs (all with the same payload size) is inexpensive and virtually "free".

[0014] The limitation on the number of channel estimates in NR may result in some time slots not using all blind decoding attempts. Even if additional users can be scheduled from the user data perspective (there is capacity available for data transmission), and even if there are enough unused CCEs to meet the aggregation level for a given WD, there may not be any PDCCHs available to schedule that WD. Therefore, PDCCHs can become a capacity bottleneck.

[0015] For example, suppose a CORESET is configured with 36 CCEs, and in the first and second OFDM symbols of the time slot, two search spaces with aggregation levels [1, 2, 4, 8, 16] and candidate [5, 4, 1, 1, 1] are associated with the CORESET. The number of search spaces monitored by WD in each time slot is as follows: Figure 4 As shown, given the time-varying search space randomization specified for NR, and the CCE constraint, the second search space is not decoded at all in some slots. Note that there are only 24 candidates in total (44 for a subcarrier spacing (SCS) of 15 kHz). This leads to an unbalanced and uncontrolled PDCCH capacity. An alternative approach is to configure the candidates in a conservative manner to ensure that the CCE constraint is not met. However, this results in inefficient resource utilization and reduced PDCCH capacity. Summary of the Invention

[0016] Some embodiments advantageously provide methods, systems, and apparatus for improved control channel element (CCE) randomization.

[0017] In some embodiments, search space randomization is performed such that blind decoding does not occur outside the CCEs covered by the channel estimation. In some embodiments, blind decoding attempts that would be blocked due to the maximum number of channel estimates are remapped to CCEs within the limit, i.e., the WD performs another (typically higher) level of channel estimation on them.

[0018] In some embodiments, a method is provided for increasing the amount of available search space while taking into account the maximum number of supported channel estimates and blind decoding.

[0019] Some implementations offer a lower probability that system capacity is limited by PDCCH capacity.

[0020] According to one aspect, a method is provided in a wireless device (WD) configured to communicate with a network node. The method includes mapping a search space to a set of non-overlapping CCEs when the WD supports additional non-overlapping CCEs for a given control channel element (CCE) aggregation level. The method also includes mapping the search space to a set of overlapping CCEs when the WD does not support additional non-overlapping CCEs. The method further includes, otherwise, not mapping the search space when the cardinality of the overlapping CCE set is less than the aggregation level of the candidate control channel.

[0021] According to this aspect, in some embodiments, the method includes randomizing N channel estimates across all CCEs in a control resource set CORESET, where N is the number of channel estimates that the WD can perform. In some embodiments, the method includes randomizing blind decoding for a subset of CCEs for which channel estimates are performed. In some embodiments, the method includes randomly selecting L CCEs, where L is equal to the highest aggregation level configured in the search space. In some embodiments, the method includes determining a set C of remaining CCEs for which channel estimates have not yet been performed. In some embodiments, the search space is mapped for the next lower aggregation level when not all CCE aggregation levels have been mapped. In some embodiments, the search space is mapped in descending order of CCE aggregation levels. In some embodiments, the method includes randomizing blind decoding for each of a plurality of channel estimates performed by the WD. In some embodiments, the method includes mapping the remaining set of blind decodes to CCEs at a given CCE aggregation level. In some embodiments, the location of the control resource set CORESET is randomized. In some embodiments, the method includes assuming a random mapping of the physical downlink control channel PDCCH and finding a corresponding CCE index for the CCE in the CCE aggregation level. In some embodiments, for each of a plurality of CCE aggregation levels, finding a corresponding index for the CCE in the CCE aggregation level is performed.

[0022] According to another aspect, a wireless device (WD) configured to communicate with a network node is provided. The WD includes processing circuitry configured to map a search space to a set of non-overlapping CCEs when the WD supports additional non-overlapping CCEs at a given control channel element (CCE) aggregation level. The processing circuitry is also configured to map the search space to a set of overlapping CCEs when the WD does not support additional non-overlapping CCEs; and otherwise, if the cardinality of the overlapping CCE set is less than the aggregation level of the candidate control channel, the search space is not mapped.

[0023] According to this aspect, in some embodiments, the processing circuitry is further configured to randomize N channel estimates across all CCEs in the control resource set CORESET, where N is the number of channel estimates that the WD can perform. In some embodiments, the processing circuitry is further configured to randomize blind decoding for a subset of CCEs for which channel estimation has been performed. In some embodiments, the processing circuitry is further configured to randomly select L CCEs, where L is equal to the highest aggregation level configured in the search space. In some embodiments, the processing circuitry is further configured to determine a set C of remaining CCEs for which channel estimation has not yet been performed. In some embodiments, when not all CCE aggregation levels have been mapped, the search space is mapped for the next lower aggregation level. In some embodiments, the search space is mapped in descending order of aggregation levels. In some embodiments, the processing circuitry is further configured to randomize blind decoding for each of the plurality of channel estimates performed by the WD. In some embodiments, the processing circuitry is further configured to map the remaining set of blind decodes to CCEs at a given CCE aggregation level. In some embodiments, the location of the control resource set CORESET is randomized. In some embodiments, the processing circuitry is further configured to assume a random mapping of the physical downlink control channel PDCCH and find the corresponding CCE index for the CCE in the CCE aggregation level. In some embodiments, for each of the multiple CCE aggregation levels, the corresponding index for the CCE is found in the CCE aggregation level. Attached Figure Description

[0024] A fuller understanding of this embodiment and its accompanying advantages and features will be more readily obtained by referring to the following detailed description when considered in conjunction with the accompanying drawings, in which: Figure 1 The PDCCH process is shown; Figure 2 This illustrates blind decoding in WD; Figure 3 This is an example of a search space used for two different WDs; Figure 4 This indicates that the search space may violate CCE constraints; Figure 5This is a schematic diagram illustrating an example network architecture of a communication system connected to a host computer via an intermediate network according to the principles of this disclosure; Figure 6 This is a block diagram illustrating a host computer communicating with a wireless device via a network node through at least a partial wireless connection, according to some embodiments of the present disclosure. Figure 7 This is a flowchart illustrating an example method for executing a client application at a wireless device, implemented in a communication system including a host computer, a network node, and a wireless device, according to some embodiments of the present disclosure. Figure 8 This is a flowchart illustrating an example method for receiving user data at a wireless device, implemented in a communication system including a host computer, a network node, and a wireless device, according to some embodiments of the present disclosure. Figure 9 This is a flowchart illustrating an example method for receiving user data from a wireless device at a host computer, implemented in a communication system including a host computer, a network node, and a wireless device, according to some embodiments of the present disclosure. Figure 10 This is a flowchart illustrating an example method for receiving user data at a host computer, implemented in a communication system including a host computer, a network node, and a wireless device, according to some embodiments of the present disclosure. Figure 11 This is a flowchart of an example process for improving the randomization of control channel elements (CCE) in a wireless device; Figure 12 This is an example of CCE mapping; Figure 13 This demonstrates how CORESET locations can be randomly mapped; Figure 14 This demonstrates how WD can be grouped at different frequency locations; and Figure 15A and Figure 15B An example comparing the result search space of a conventional system and some embodiments disclosed herein is shown. Detailed Implementation

[0025] Before describing the exemplary embodiments in detail, it should be noted that the embodiments primarily exist in combinations of device components and processing steps related to improved control channel element (CCE) randomization. Therefore, where appropriate, conventional symbols in the drawings have been used to denote components, and only those specific details relevant to understanding the embodiments are shown so as not to obscure this disclosure with details that will be readily understood by those skilled in the art who benefit from the description herein. Throughout the description, the same numbers denote the same elements.

[0026] As used herein, relational terms (such as “first” and “second”, “top” and “bottom”, and the like) may be used only to distinguish one entity or element from another, and do not necessarily require or imply any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the concepts described herein. As used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It will be further understood that the terms “comprising,” “including,” “containing,” and / or “owning,” as used herein, specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0027] In the embodiments described herein, the connecting terms “communicating with” and similar expressions can be used to indicate electrical or data communication, which may be accompanied, for example, by physical contact, induction, electromagnetic radiation, radio signaling, infrared signaling, or optical signaling. Those skilled in the art will appreciate that multiple components can interoperate, and modifications and variations in electrical and data communication are possible.

[0028] In some embodiments described herein, the terms “coupled,” “connected,” and the like may be used herein to indicate a connection, although not necessarily a direct one, and may include wired and / or wireless connections.

[0029] As used herein, the term "network node" can refer to any type of network node included in a radio network, and may also include any of the following: base station (BS), radio base station, base transceiver station (BTS), base station controller (BSC), radio network controller (RNC), g node B (gNB), evolved node B (eNB or eNodeB), node B, multi-standard radio (MSR) radio node (such as MSR BS), multi-cell / multicast coordination entity (MCE), integrated access and backhaul (IAB) node, relay node, donor node of control relay, radio access point (AP), transmission point, transmission node, remote radio unit (RRU), remote radio head (RRH), core network node (e.g., mobility management entity (MME), ad hoc network (SON) node, coordination node, location node, MDT node, etc.), external node (e.g., third-party node, node outside the current network), node in distributed antenna system (DAS), spectrum access system (SAS) node, element management system (EMS), etc. Network nodes may also include test equipment. The term “radio node” as used in this article can also be used to refer to a wireless device (WD), such as a wireless device (WD) or a radio network node.

[0030] In some embodiments, the non-limiting terms “wireless device (WD)” or “user equipment (UE)” are used interchangeably. A WD as used herein can be any type of wireless device capable of communicating with a network node or another WD via radio signals, such as a wireless device (WD). A WD can also be a radio communication device, a target device, a device-to-device (D2D) WD, a machine-type WD or a WD capable of machine-to-machine (M2M) communication, a low-cost and / or low-complexity WD, a sensor equipped with a WD, a tablet computer, a mobile terminal, a smartphone, a laptop embedded device (LEE), a laptop mounted device (LME), a USB dongle, a client premises equipment (CPE), an Internet of Things (IoT) device, or a narrowband IoT (NB-IoT) device, etc.

[0031] Furthermore, in some embodiments, the generic term "radio network node" is used. It can be any type of radio network node, which may include any of the following: base station, radio base station, base transceiver station, base station controller, network controller, RNC, evolved Node B (eNB), Node B, gNB, multi-cell / multicast coordination entity (MCE), IAB node, relay node, access point, radio access point, remote radio unit (RRU), and remote radio head (RRH).

[0032] Note that although terms from a particular wireless system (such as, for example, 3GPP LTE and / or New Radio (NR)) may be used in this disclosure, this should not be construed as limiting the scope of this disclosure to only the aforementioned systems. Other wireless systems, including but not limited to Wideband Code Division Multiple Access (WCDMA), Global Microwave Access Interoperability (WiMax), Ultra Mobile Broadband (UMB), and Global System for Mobile Communications (GSM), may also benefit from utilizing the concepts covered in this disclosure.

[0033] It should be noted further that the functions performed by wireless devices or network nodes as described herein can be distributed across multiple wireless devices and / or network nodes. In other words, it is conceivable that the functions of the network nodes and wireless devices described herein are not limited to being performed by a single physical device, and can actually be distributed across several physical devices.

[0034] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It will also be further understood that terms used herein should be interpreted as having the same meaning as they have in the context of this specification and the relevant field, and will not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0035] Some implementations provide improved control channel element (CCE) randomization.

[0036] Now, returning to the drawn graphic, similar components are referred to using similar reference numerals. Figure 5 The diagram illustrates a communication system 10 (such as a 3GPP-type cellular network supporting standards such as LTE and / or NR (5G)) according to an embodiment. The communication system 10 includes an access network 12 (such as a radio access network) and a core network 14. The access network 12 includes multiple network nodes 16a, 16b, 16c (collectively referred to as network nodes 16), such as NBs, eNBs, gNBs, or other types of wireless access points, each defining a corresponding coverage area 18a, 18b, 18c (collectively referred to as coverage area 18). Each network node 16a, 16b, 16c can be connected to the core network 14 via a wired or wireless connection 20. A first wireless device (WD) 22a located in coverage area 18a is configured to wirelessly connect to or be paged by the corresponding network node 16a. A second WD 22b in coverage area 18b can wirelessly connect to the corresponding network node 16b. Although multiple WDs 22a, 22b (collectively referred to as wireless devices 22) are shown in this example, the disclosed embodiments are equally applicable to situations where only one WD is in the coverage area or where only one WD is connected to the corresponding network node 16. It should be noted that although only two WDs 22 and three network nodes 16 are shown for convenience, the communication system may include more WDs 22 and network nodes 16.

[0037] It is also anticipated that WD 22 can communicate simultaneously with more than one network node 16 and more than one type of network node 16, and / or be configured to communicate individually with more than one network node 16 and more than one type of network node 16. For example, WD 22 can have dual connectivity with LTE-enabled network nodes 16 and the same or different NR-enabled network nodes 16. As an example, WD 22 can communicate with an eNB of LTE / E-UTRAN and a gNB of NR / NG-RAN.

[0038] The communication system 10 itself can be connected to a host computer 24, which can be implemented as hardware and / or software of a standalone server, a cloud-based server, a distributed server, or as a processing resource in a server farm. The host computer 24 may be owned or controlled by a service provider, or may be operated by or on behalf of the service provider. Connections 26, 28 between the communication system 10 and the host computer 24 can extend directly from the core network 14 to the host computer 24, or can extend via an optional intermediate network 30. The intermediate network 30 can be one of a public, private, or hosted network, or a combination of more than one public, private, or hosted network. The intermediate network 30 (if any) can be a backbone network or the Internet. In some embodiments, the intermediate network 30 may include two or more subnetworks (not shown).

[0039] Figure 5 The overall communication system enables connectivity between one of the connected WDs 22a and 22b and the host computer 24. This connectivity can be described as an over-the-top (OTT) connection. The host computer 24 and the connected WDs 22a and 22b are configured to transmit data and / or signaling via the OTT connection using access network 12, core network 14, any intermediate network 30, and other possible infrastructure (not shown) acting as intermediaries. The OTT connection can be transparent in the sense that at least some of the participating communication devices are unaware of the routes for uplink and downlink communications. For example, the past routes of incoming downlink communications with data originating from the host computer 24 and to be forwarded (e.g., handed over) to the connected WD 22a may not be required or need to be communicated to network node 16. Similarly, network node 16 does not need to know the future routes of outgoing uplink communications originating from WD 22a toward the host computer 24.

[0040] The wireless device 22 is configured to include a CCE unit 34, which can be configured to map the search space to a set of control channel elements based at least in part on the number of overlapping CCEs and the CCE aggregation level.

[0041] Now refer to Figure 5The following describes an exemplary implementation of the WD 22, network node 16, and host computer 24 described in the preceding paragraphs according to an embodiment. In the communication system 10, the host computer 24 includes hardware (HW) 38, which includes a communication interface 40 configured to establish and maintain wired or wireless connections with interfaces to different communication devices of the communication system 10. The host computer 24 also includes processing circuitry 42, which may have storage and / or processing capabilities. Processing circuitry 42 may include a processor 44 and memory 46. In particular, as an addition to or alternative to the processor (such as a central processing unit) and memory, processing circuitry 42 may include integrated circuits for processing and / or control, such as one or more processors and / or processor cores suitable for executing instructions and / or FPGAs (Field-Programmable Gate Arrays) and / or ASICs (Application-Specific Integrated Circuits). Processor 44 may be configured to access (e.g., write and / or read) memory 46, which may include any kind of volatile and / or non-volatile memory, such as cache and / or buffer memory and / or RAM (random access memory) and / or ROM (read-only memory) and / or optical memory and / or EPROM (erasable programmable read-only memory).

[0042] Processing circuitry 42 may be configured to control any methods and / or processes described and / or performed herein, and / or to cause such methods and / or processes to be performed, for example, by host computer 24. Processor 44 corresponds to one or more processors 44 for performing the functions of host computer 24 as described herein. Host computer 24 includes memory 46 configured to store data, programming software code, and / or other information as described herein. In some embodiments, software 48 and / or host application 50 may include instructions that, when executed by processor 44 and / or processing circuitry 42, cause processor 44 and / or processing circuitry 42 to perform the processes described herein with respect to host computer 24. The instructions may be software associated with host computer 24.

[0043] Software 48 may be executable by processing circuitry 42. Software 48 includes a host application 50. Host application 50 may be operable to provide services to remote users, such as WD22 connected via an OTT connection 52 terminated between WD22 and host computer 24. In providing services to remote users, host application 50 may provide user data, which is transmitted using OTT connection 52. “User data” may be data and information described herein for implementing the functions described. In one embodiment, host computer 24 may be configured to provide control and functionality to a service provider and may be operated by or on behalf of the service provider. Processing circuitry 42 of host computer 24 enables host computer 24 to observe, monitor, control network node 16 and / or wireless device 22, and to transmit and / or receive data to and / or from network node 16 and / or wireless device 22.

[0044] The communication system 10 also includes a network node 16, which is provided within the communication system 10 and includes hardware 58 that enables it to communicate with the host computer 24 and with the WD 22. Hardware 58 may include: a communication interface 60 for establishing and maintaining wired or wireless connections to interfaces with different communication devices of the communication system 10; and a radio interface 62 for establishing and maintaining at least a wireless connection 64 with the WD 22 located within the coverage area 18 served by the network node 16. The radio interface 62 may be configured as or may include, for example, one or more RF transmitters, one or more RF receivers, and / or one or more RF transceivers. The communication interface 60 may be configured to facilitate a connection 66 to the host computer 24. The connection 66 may be direct, or it may traverse the core network 14 of the communication system 10 and / or one or more intermediate networks 30 outside the communication system 10.

[0045] In the illustrated embodiment, the hardware 58 of network node 16 also includes processing circuitry 68. Processing circuitry 68 may include a processor 70 and memory 72. Specifically, as an addition to or alternative to the processor (such as a central processing unit) and memory, processing circuitry 68 may include integrated circuits for processing and / or control, such as one or more processors and / or processor cores suitable for executing instructions and / or FPGAs (Field-Programmable Gate Arrays) and / or ASICs (Application-Specific Integrated Circuits). Processor 70 may be configured to access (e.g., write to and / or read from) memory 72, which may include any kind of volatile and / or non-volatile memory, such as cache and / or buffer memory and / or RAM (Random Access Memory) and / or ROM (Read-Only Memory) and / or optical memory and / or EPROM (Erasable Programmable Read-Only Memory).

[0046] Therefore, network node 16 further includes software 74, which is internally stored, for example, in memory 72, or stored in external memory (e.g., a database, storage array, network storage device, etc.) accessible by network node 16 via an external connection. Software 74 may be executable by processing circuitry 68. Processing circuitry 68 may be configured to control any methods and / or processes described herein, and / or to cause such methods and / or processes to be executed, for example, by network node 16. Processor 70 corresponds to one or more processors 70 for performing the functions of network node 16 as described herein. Memory 72 is configured to store data, programming software code, and / or other information as described herein. In some embodiments, software 74 may include instructions that, when executed by processor 70 and / or processing circuitry 68, cause processor 70 and / or processing circuitry 68 to perform the processes described herein for network node 16.

[0047] The communication system 10 also includes the previously mentioned WD 22. The WD 22 may have hardware 80, which may include a radio interface 82 configured to establish and maintain a wireless connection 64 with a network node 16 serving the coverage area 18 where the WD 22 is currently located. The radio interface 82 may be configured as or may include, for example, one or more RF transmitters, one or more RF receivers, and / or one or more RF transceivers.

[0048] The hardware 80 of the WD 22 also includes processing circuitry 84. Processing circuitry 84 may include a processor 86 and memory 88. In particular, as an addition to or alternative to the processor (such as a central processing unit) and memory, processing circuitry 84 may include integrated circuits for processing and / or control, such as one or more processors and / or processor cores suitable for executing instructions and / or FPGAs (Field-Programmable Gate Arrays) and / or ASICs (Application-Specific Integrated Circuits). Processor 86 may be configured to access (e.g., write to and / or read from) memory 88, which may include any kind of volatile and / or non-volatile memory, such as cache and / or buffer memory and / or RAM (Random Access Memory) and / or ROM (Read-Only Memory) and / or optical memory and / or EPROM (Erasable Programmable Read-Only Memory).

[0049] Therefore, WD 22 may also include software 90, which is stored, for example, in memory 88 at WD 22 or in external memory accessible to WD 22 (e.g., a database, storage array, network storage device, etc.). Software 90 may be executable by processing circuitry 84. Software 90 may include a client application 92. Client application 92 may be operable to provide services to human or non-human users via WD 22 with the support of host computer 24. In host computer 24, a executing host application 50 may communicate with the executing client application 92 via an OTT connection 52 terminated between WD 22 and host computer 24. When providing services to a user, client application 92 may receive request data from host application 50 and provide user data in response to the request data. OTT connection 52 may transmit both request data and user data. Client application 92 may interact with the user to generate the user data it provides.

[0050] Processing circuitry 84 may be configured to control any of the methods and / or processes described herein, and / or to cause such methods and / or processes to be performed, for example, by WD 22. Processor 86 corresponds to one or more processors 86 for performing the functions of WD 22 described herein. WD 22 includes memory 88 configured to store data, programming software code, and / or other information described herein. In some embodiments, software 90 and / or client application 92 may include instructions that, when executed by processor 86 and / or processing circuitry 84, cause processor 86 and / or processing circuitry 84 to perform the processes described herein with respect to WD 22. For example, processing circuitry 84 of wireless device 22 may include CCE unit 34, which may be configured to map the search space to a set of control channel elements, at least in part, based on the number of overlapping CCEs and the CCE aggregation level.

[0051] In some embodiments, the internal operations of network node 16, WD 22, and host computer 24 can be as follows: Figure 6 As shown, and independently, the surrounding network topology can be Figure 5 The network topology.

[0052] Figure 6In the diagram, OTT connection 52 is abstractly depicted to illustrate communication between host computer 24 and wireless device 22 via network node 16, without explicitly mentioning any intermediate devices or the exact routing of messages through these devices. The network infrastructure can determine the routing, which it can configure to be hidden from WD 22, the service provider operating host computer 24, or both. While OTT connection 52 is active, the network infrastructure can further make decisions, through which it dynamically changes the routing (e.g., based on network load balancing considerations or reconfiguration).

[0053] The wireless connection 64 between WD 22 and network node 16 is based on the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments utilize an OTT connection 52 to improve the performance of OTT services provided to WD 22, in which the wireless connection 64 may form a final segment. More precisely, the teachings of some of these embodiments can improve data rates, latency, and / or power consumption, and thereby provide beneficial effects such as reduced user wait times, relaxed file size limits, better responsiveness, and extended battery life.

[0054] In some embodiments, a measurement process may be provided for the purpose of facilitating the monitoring of data rates, latency, and other factors improved in one or more embodiments. Optional network functions may also be available for reconfiguring the OTT connection 52 between host computer 24 and WD 22 in response to changes in measurement results. The measurement process and / or the network functions for reconfiguring the OTT connection 52 may be implemented via software 48 of host computer 24 or software 90 of WD 22, or both. In embodiments, sensors (not shown) may be deployed in or associated with a communication device within the OTT connection 52; the sensors may participate in the measurement process by providing values ​​of the monitored quantities illustrated above or by providing values ​​of other physical quantities from which the software 48, 90 can calculate or estimate the monitored quantities. Reconfiguration of the OTT connection 52 may include message formats, retransmission settings, preferred routing, etc.; reconfiguration does not affect network node 16 and may be unknown or undetectable to network node 16. Some such processes and functions may be known and implemented in the art. In some embodiments, the measurement may involve proprietary WD signaling that facilitates the host computer 24's measurement of throughput, propagation time, latency, etc. In some embodiments, measurement can be achieved because the software 48, 90 enables messages to be transmitted using the OTT connection 52 while monitoring propagation time, errors, etc., especially empty or 'fake' messages.

[0055] Therefore, in some embodiments, the host computer 24 includes: processing circuitry 42 configured to provide user data; and a communication interface 40 configured to forward the user data to a cellular network for transmission to WD 22. In some embodiments, the cellular network further includes a network node 16 having a radio interface 62. In some embodiments, the network node 16 is configured and / or its processing circuitry 68 is configured to perform the functions and / or methods described herein for: preparing / initiating / maintaining / supporting / terminating transmissions to WD 22 and / or preparing / terminating / maintaining / supporting / terminating reception of transmissions from WD 22.

[0056] In some embodiments, host computer 24 includes processing circuitry 42 and a communication interface 40 configured to receive user data from transmissions from WD 22 to network node 16. In some embodiments, WD 22 is configured to perform the functions and / or methods described herein for the following operations and / or includes a radio interface 82 and / or processing circuitry 84 configured to perform the functions and / or methods described herein for the following operations: preparing / initiating / maintaining / supporting / terminating transmissions to network node 16 and / or preparing / terminating / maintaining / supporting / terminating reception of transmissions from network node 16.

[0057] Although Figure 5 and Figure 6 Various “units” (such as CCE unit 34) are shown as residing within the respective processors, but it is contemplated that these units can be implemented such that a portion of the unit is stored in a corresponding memory within the processing circuitry. In other words, the units can be implemented in hardware or through a combination of hardware and software within the processing circuitry.

[0058] Figure 7 This illustrates, according to one embodiment, in a communication system (e.g., such as...) Figure 5 and Figure 2 The flowchart illustrates an example method implemented in a communication system. The communication system may include a host computer 24, a network node 16, and a WD 22, which may be referenced... Figure 6The aforementioned host computers, network nodes, and WDs. In the first step of the method, host computer 24 provides user data (block S100). In an optional sub-step of the first step, host computer 24 provides user data by executing a host application (e.g., such as host application 50) (block S102). In the second step, host computer 24 initiates a transmission carrying user data to WD 22 (block S104). In an optional third step, according to the teachings of the embodiments described throughout this disclosure, network node 16 transmits user data to WD 22 (block S106), the user data being carried in the transmission initiated by host computer 24. In an optional fourth step, WD 22 executes a client application (e.g., such as client application 92) associated with host application 50 executed by host computer 24 (block S108).

[0059] Figure 8 This illustrates, according to one embodiment, in a communication system (e.g., such as...) Figure 5 The flowchart illustrates an example method implemented in a communication system. The communication system may include a host computer 24, a network node 16, and a WD 22, which may be referenced... Figure 5 and Figure 6 The host computer, network node, and WD described herein. In the first step of the method, host computer 24 provides user data (block S110). In an optional sub-step (not shown), host computer 24 provides user data by executing a host application (e.g., host application 50). In the second step, host computer 24 initiates a transmission carrying user data to WD 22 (block S112). According to the teachings of the embodiments described throughout this disclosure, the transmission may be carried out via network node 16. In an optional third step, WD 22 receives the user data carried in the transmission (block S114).

[0060] Figure 9 This illustrates, according to one embodiment, in a communication system (e.g., such as...) Figure 5 The flowchart illustrates an example method implemented in a communication system. The communication system may include a host computer 24, a network node 16, and a WD 22, which may be referenced... Figure 5 and Figure 6The aforementioned host computers, network nodes, and WDs. In an optional first step of the method, WD 22 receives input data provided by host computer 24 (block S116). In an optional sub-step of the first step, WD 22 executes client application 92, which responds to the received input data provided by host computer 24 to provide user data (block S118). Additionally or alternatively, in an optional second step, WD 22 provides user data (block S120). In an optional sub-step of the second step, WD provides user data by executing a client application (e.g., such as client application 92) (block S122). In providing user data, the executed client application 92 may further consider user input received from the user. Regardless of the specific manner in which user data is provided, WD 22 may initiate the transfer of user data to host computer 24 in an optional third sub-step (block S124). In accordance with the teachings of the embodiments described throughout this disclosure, in the fourth step of the method, host computer 24 receives user data transmitted from WD 22 (block S126).

[0061] Figure 10 This illustrates, according to one embodiment, in a communication system (e.g., such as...) Figure 5 The flowchart illustrates an example method implemented in a communication system. The communication system may include a host computer 24, a network node 16, and a WD 22, which may be referenced... Figure 5 and Figure 6 The aforementioned host computer, network node, and WD. In an optional first step of the method, network node 16 receives user data from WD 22 in accordance with the teachings of the embodiments described throughout this disclosure (block S128). In an optional second step, network node 16 initiates a transmission of the received user data to host computer 24 (block S130). In a third step, host computer 24 receives the user data carried in the transmission initiated by network node 16 (block S132).

[0062] Figure 11This is a flowchart of an example process in a wireless device 22 according to some embodiments of the present disclosure. One or more blocks described herein can be performed by one or more elements of the wireless device 22, such as one or more of processing circuitry 84 (including CCE unit 34), processor 86, radio interface 82, and / or communication interface 60. The wireless device 22, such as via processing circuitry 84 and / or processor 86 and / or radio interface 82, is configured to: map the search space to a set of non-overlapping CCEs when the WD supports additional non-overlapping CCEs at a given control channel element CCE aggregation level (block S134). The method also includes mapping the search space to a set of overlapping CCEs when the WD 22 does not support additional non-overlapping CCEs (block S136). The method further includes: otherwise, if the cardinality of the overlapping CCE set is less than the aggregation level of the candidate control channel, then the search space is not mapped (block S138).

[0063] In some embodiments, the method includes randomizing N channel estimates across all CCEs in the control resource set CORESET, where N is the number of channel estimates that WD 22 can perform. In some embodiments, the method includes randomizing blind decoding for a subset of CCEs for which channel estimates have been performed. In some embodiments, the method includes randomly selecting L CCEs, where L is equal to the highest aggregation level configured in the search space. In some embodiments, the method includes determining a set C of remaining CCEs for which channel estimates have not yet been performed. In some embodiments, when not all CCE aggregation levels have been mapped, the search space is mapped for the next lower aggregation level. In some embodiments, the search space is mapped in descending order of CCE aggregation levels. In some embodiments, the method includes randomizing blind decoding for each of the plurality of channel estimates performed by WD 22. In some embodiments, the method includes mapping the remaining set of blind decodes to CCEs at a given CCE aggregation level. In some embodiments, the location of the control resource set CORESET is randomized. In some embodiments, the method includes assuming a random mapping of the physical downlink control channel PDCCH and finding a corresponding CCE index for the CCE in the CCE aggregation level. In some embodiments, finding a corresponding index for the CCE in the CCE aggregation level is performed for each of the plurality of CCE aggregation levels.

[0064] After describing the general process flow of the arrangements of this disclosure and providing examples of hardware and software arrangements for implementing the processes and functions of this disclosure, the following sections provide details and examples of arrangements for improved control channel element (CCE) randomization.

[0065] In some embodiments, search space randomization is performed so that blind decoding is not discarded or skipped due to limited channel estimation. Some embodiments ensure the use of full blind decoding capabilities despite limitations in the number of channel estimates. In some embodiments, PDCCH candidate mapping is performed while considering the number of available channel estimates.

[0066] Variant A – First, select a CCE with channel estimation, then map blind decoding. Example 1 In some embodiments, a method is provided in which each search space (in descending order of aggregation level) is mapped to a set of non - overlapping CCEs if WD 22 supports the additional set of non - overlapping CCEs required for the aggregation level of the search space. Otherwise, the search space is mapped to the CCEs selected only for the search spaces of higher aggregation levels. Otherwise, the search space is skipped. In some embodiments, supporting the additional set of non - overlapping CCEs includes supporting additional channel estimation for non - overlapping CCEs.

[0067] Example 2 In some embodiments, channel estimation is randomized across all CCEs in the CORESET, and then blind decoding is randomized within the subset of CCEs with channel estimation.

[0068] In some embodiments, one or more of the following steps prioritize the highest aggregation level. There are also other possibilities.

[0069] 1. Let S = all CCEs in the CORESET; 2. Let C = {} (empty set); 3. Let N = the number of channel estimates that WD 22 is capable or allowed to use for this set of search spaces, expressed in CCEs; 4. Let L = the highest aggregation level configured [in the set of search spaces]; 5. If at least one of the following a, b, or (optionally) c is satisfied, go to 10; a. N < L; or b. It is not possible to find L consecutive CCEs in S; or c. The number of CCEs for which channel estimates have been obtained at aggregation level L is sufficient to handle the number of PDCCH candidates at that aggregation level; 6. (Randomly) Select L (consecutive) CCEs in S for channel estimation and add these CCEs to the set C. (The selection of the L CCEs can be performed according to a hash function of a pseudorandom sequence or other means, as long as network node 16 and WD 22 have the same understanding of which CCEs are selected.); 7. S = S\C (i.e., S is the remaining CCEs for which channel estimation has not been performed); 8. N = NL (i.e., subtract the number of CCEs not selected in the previous step; this expression applies to the CCE definition used in NR). 9. Go to 5; 10. If not all aggregation levels are considered, and N > 0: then set L = the next lower aggregation level, go to 5; 11. Set C contains CCEs with channel estimation; and / or 12. For example, using equations similar to those in 3GPP Release 15 Technical Standard (TS) 38.213, blind decoding within set C randomizes the search space.

[0070] Variant B – Initially selects blind decoding; if the channel estimation limit is reached, the selection strategy is changed. Example 3 Some embodiments include a method in which each search space (in descending order of aggregation level) is mapped to a CCE selected only for search spaces at higher aggregation levels (if any), and wherein, if WD 22 supports an additional set of non-overlapping CCEs required for the aggregation level of the search space, the search space is otherwise mapped to a set of non-overlapping CCEs. Otherwise, search space candidates are skipped.

[0071] Example 4 Some embodiments include a method in which random blind decoding is performed in the NR (or some variant thereof) until a limit set by the number of channel estimates is reached. The remaining blind decoding can be mapped to a CCE that has already been covered by a larger aggregation level (and for which there is no blind decoding yet with the same aggregation level), such as... Figure 12 As shown.

[0072] An example process includes one or more of the following steps. 1. Generate M top-level candidates using the formula from Section 10.1 of 3GPP Release 15 TS 38.213 (i.e., the aggregation level is the maximum aggregation level configured for this search space set). 2. For each top-level candidate mi, generate M_mi sub-candidates using the same formula, but Ncce = L_mi, where L_mi is the aggregation level of mi; and / or 3. Add the starting CCE index of mi to each sub-candidate mij generated in step 2.

[0073] Example 5 In some embodiments, the location of the CORESET is randomized. To control the number of channel estimates performed by WD 22, network node 16 can be configured with a smaller CORESET. This results in more frequent overlap of PDCCH candidates, thereby reducing the number of channel estimates. However, this also increases the likelihood of WD 22 blocking each other. To reduce the likelihood that all WD 22 have their candidates in a (reduced size) CORESET, in some embodiments, the location of the CORESET for each WD 22 is also randomized. This method creates a grouping strategy for WD 22 by mapping the CORESET of WD 22 to random locations in the frequency domain.

[0074] In some embodiments, only the size of the CORESET (how many CCEs it has) is defined, rather than configuring the exact location of the CORESET. Define the offset. This controls the mapping position of the CORESET in the frequency domain. Specifically, the position of the CORESET in the frequency domain can then be calculated. The CORESET can occupy a certain area in the frequency domain. (Modal operation is optional). Variables It can be a random function generated by another hash function known to both WD 22 and network node 16. In some embodiments, It can refer to a physical resource block (PRB) or a subcarrier index or a set of PRBs in a resource grid.

[0075] Figure 13 An example random CORESET mapping is shown in the figure.

[0076] Figure 14 The diagram shows the different parts of the WD 22 grouped into frequency domain resources. Figure 14 This demonstrates how WD 22 can be grouped at different frequency locations. This example contains 15 WD 22s. The numbers in parentheses represent the indices of the WD 22s.

[0077] Example 6 In some embodiments, the process for performing blind decoding is enhanced so that PDCCH candidates are not ignored due to the number of non-overlapping CCE constraints. An example process may include one or more of the following steps.

[0078] (Step 1) First, WD 22 may assume that the randomized mapping of candidates to CCEs (as configured in CORESET) is performed as in NR. WD 22 starts with the candidates at the highest aggregation level and finds the corresponding CCE index for the candidates in that aggregation level. Then the number of NO-CCEs is calculated. This operation is then repeated for other aggregation levels. At any point in time, if the number of NO-CCEs exceeds a limit, the procedure stops. This limit is set by the maximum number of NO-CCEs that WD 22 can blindly decode (as described in the standard specification), or by the number configured by the network when configuring the search space. In some embodiments, this may be implemented by introducing a field in the “SearchSpace” information element (IE) in 3GPP TS 38.331. If not configured, WD 22 may assume default values ​​introduced or configured in the standard specification; and / or (Step 2) At this point, WD 22 has recorded the set of CCE indices that have been visited. Next, for the remaining candidates, WD 22 uses the set of CCE indices as input to the randomization function in NR in step 1, instead of using the original CCE indices (as configured).

[0079] The following example illustrates the benefits of the solution disclosed herein. Assume two sets of search spaces are configured. When WD 22 performs blind decoding on the common search space and the first search space set, WD 22 performs channel estimation on 40 NO-CCEs. Therefore, for the second search space, WD 22 can perform channel estimation on only 16 NO-CCEs. In this example, assume the second search space has [6, 4, 4, 2, 1] candidates with aggregation levels [1, 2, 4, 8, 16].

[0080] Figure 15A and Figure 15B These are examples illustrating how some embodiments improve upon conventional processes. Figure 15A It is shown that performing blind decoding on this search space might require channel estimation for 34 NO-CCEs, which exceeds the budget. Therefore, it may be impossible to decode any candidates, and the entire search space is ignored by WD 22. Figure 15B Advantages of some embodiments are illustrated. Similar to conventional systems, decoding the eight candidates at the second aggregation level would violate constraints, but in some embodiments disclosed herein, other candidates are mapped to already visited CCEs (…). Figure 8 The CCEs in the data are 16, 17, ..., 31, and there are no missing candidates.

[0081] When added to NR, some implementations can be incorporated into section 10.1 of 3GPP Release 15 TS 38.213 and the corresponding section of the 6G standard.

[0082] As those skilled in the art will appreciate, the concepts described herein can be implemented as methods, data processing systems, computer program products, and / or computer storage media storing executable computer programs. Therefore, the concepts described herein can take the form of purely hardware embodiments, purely software embodiments, or embodiments combining software and hardware aspects, all of which are collectively referred to herein as “circuit” or “module”. Any process, step, action, and / or function described herein can be performed by and / or associated with a corresponding module, which can be implemented in software and / or firmware and / or hardware. Furthermore, this disclosure can take the form of a computer program product stored on a tangible computer-readable storage medium having computer program code implemented in a computer-executable medium. Any suitable tangible computer-readable medium can be utilized, including hard disks, CD-ROMs, electronic storage devices, optical storage devices, or magnetic storage devices.

[0083] Some embodiments are described herein with reference to flowchart illustrations and / or block diagrams of methods, systems, and computer program products. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer (thereby creating a special-purpose computer), a special-purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create components for implementing the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams.

[0084] These computer program instructions may also be stored in a computer-readable storage medium or storage medium, which may instruct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of writing comprising instruction components that implement the functions / actions specified in one or more blocks of a flowchart and / or block diagram.

[0085] Computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0086] It is important to understand that the functions / actions shown in the boxes may not be performed in the order shown in the operation diagram. For example, two boxes shown consecutively may actually be executed substantially concurrently, or the boxes may sometimes be executed in reverse order, depending on the functions / actions involved. Although some diagrams include arrows on the communication path to indicate the main direction of communication, it is important to understand that communication may proceed in the opposite direction to the arrows shown.

[0087] Computer program code used to perform the operations of the concepts described herein can be written in an object-oriented programming language such as Python, Java®, or C++. However, computer program code used to perform the operations of this disclosure can also be written in a conventional procedural programming language such as the "C" programming language. The program code can be executed entirely on the user's computer, partially on the user's computer as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer. In the latter case, the remote computer can be connected to the user's computer via a local area network (LAN) or a wide area network (WAN), or can connect to an external computer (e.g., via the Internet through an Internet service provider).

[0088] Many different embodiments have been disclosed herein in conjunction with the foregoing description and accompanying drawings. It will be understood that literally describing and illustrating every combination and sub-combination of these embodiments would be excessively repetitive and confusing. Accordingly, all embodiments can be combined in any manner and / or combination, and this specification, including the accompanying drawings, should be understood as a complete written description of all combinations and sub-combinations constituting the embodiments described herein and the ways and processes of making and using them, and should support the claims for any such combinations or sub-combinations.

[0089] The abbreviations that may be used in the preceding description include: CCE Control Channel Element CORESET Core Resource Set PDCCH (Physical Downlink Control Channel) REG Resource Element Group Those skilled in the art will appreciate that the embodiments described herein are not limited to the specific examples and descriptions above. Furthermore, unless stated otherwise above, it should be noted that all figures are not to scale. Based on the foregoing teachings, various modifications and variations are possible without departing from the scope of the following claims.

Claims

1. A method in a wireless device WD (22) configured to communicate with a network node (16), the method comprising: When the WD (22) supports additional non-overlapping CCEs at a given control channel element CCE aggregation level, the search space is mapped (S134) to the set of non-overlapping CCEs; When the WD (22) does not support the additional non-overlapping CCE, the search space is mapped (S136) to the set of overlapping CCEs; as well as Otherwise, when the cardinality of the overlapping CCE set is less than the aggregation level of the candidate control channel, the search space is not mapped (S138).

2. The method of claim 1 further includes randomizing N channel estimates across all CCEs in the control resource set CORESET, where N is the number of channel estimates that the WD (22) can perform.

3. The method according to claim 2 further includes randomizing blind decoding on a subset of the CCEs used for performing channel estimation.

4. The method according to any one of claims 2 and 3, further comprising randomly selecting L CCEs, where L is equal to the highest aggregation level configured in the search space.

5. The method according to any one of claims 1-4, further comprising determining a set C of remaining CCEs for which channel estimation has not yet been performed.

6. The method according to any one of claims 1-5, wherein, When not all CCE aggregation levels have been mapped, the search space is mapped for the next lower aggregation level.

7. The method according to any one of claims 1-6, wherein, The search space is mapped in descending order of CCE aggregation level.

8. The method according to any one of claims 1-7, further comprising randomizing blind decoding for each of the plurality of channel estimates performed on the WD (22).

9. The method of claim 8, further comprising mapping the remaining blind decoding set to CCEs at the given CCE aggregation level.

10. The method according to any one of claims 1-9, wherein, The location of the control resource set CORESET is randomized.

11. The method according to any one of claims 1-10, further comprising assuming a random mapping of the physical downlink control channel PDCCH, and finding the corresponding CCE index for the CCE in the CCE aggregation level.

12. The method according to claim 11, wherein, For each of the multiple CCE aggregation levels, the corresponding index is found for the CCE within that CCE aggregation level.

13. A wireless device WD (22) configured to communicate with a network node (16), the WD (22) including processing circuitry (82) configured to: When the WD (22) supports additional non-overlapping CCEs at a given control channel element CCE aggregation level, the search space is mapped to the set of non-overlapping CCEs; When the WD (22) does not support the additional non-overlapping CCEs, the search space is mapped to the set of overlapping CCEs; and Otherwise, if the cardinality of the overlapping CCE set is less than the aggregation level of the candidate control channel, the search space is not mapped.

14. The WD (22) according to claim 13, wherein, The processing circuit (82) is also configured to randomize N channel estimates across all CCEs in the control resource set CORESET, where N is the number of channel estimates that the WD (22) is capable of performing.

15. The WD (22) according to claim 14, wherein, The processing circuit (82) is also configured to randomize blind decoding on a subset of the CCE that performs channel estimation.

16. The WD (22) according to any one of claims 14 and 15, wherein, The processing circuit (82) is also configured to randomly select L CCEs, where L is equal to the highest aggregation level configured in the search space.

17. The WD (22) according to any one of claims 13-16, wherein, The processing circuit (82) is also configured to determine the set C of the remaining CCEs for which channel estimation has not yet been performed.

18. The WD (22) according to any one of claims 13-17, wherein, When not all CCE aggregation levels have been mapped, the search space is mapped for the next lower aggregation level.

19. The WD (22) according to any one of claims 13-18, wherein, The search space is mapped in descending order of aggregation level.

20. The WD (22) according to any one of claims 13-19, wherein, The processing circuit (82) is also configured to randomize blind decoding for each of the plurality of channel estimates performed by the WD (22).

21. The WD (22) according to claim 20, wherein, The processing circuit (82) is also configured to map the remaining blind decoding set to the CCE of the given CCE aggregation level.

22. The WD (22) according to any one of claims 13-21, wherein, The location of the control resource set CORESET is randomized.

23. The WD (22) according to any one of claims 13-22, wherein, The processing circuit (82) is also configured to assume a random mapping of the physical downlink control channel PDCCH and to find the corresponding CCE index for the CCE in the CCE aggregation level.

24. The WD (22) according to claim 23, wherein, For each of the multiple CCE aggregation levels, perform the operation of finding the corresponding index for the CCE at that CCE aggregation level.

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