Improved control channel element, cce, randomization

Abstract

A method, system and apparatus 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 non-overlapping control channel elements, CCEs, when the WD supports additional non-overlapping CCEs for a given CCE aggregation level. The method includes mapping a search space to a set of CCEs selected only for a search space of a CCE aggregation level higher than the given CCE aggregation level when the WD does not support additional non-overlapping CCEs. The method includes otherwise, not mapping the search space.

Description

[0001] IMPROVED CONTROL CHANNEL ELEMENT, CCE, RANDOMIZATION

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to wireless communications, and in particular, to improved control channel element (CCE) randomization.

[0004] BACKGROUND

[0005] The Third Generation Partnership Project (3GPP) has developed and is developing standards for Fourth Generation (4G) (also referred to as Long Term Evolution (LTE)) and Fifth Generation (5G) (also referred to as New Radio (NR)) wireless communication systems. Such systems provide, among other features, broadband communication between network nodes, such as base stations, and mobile wireless devices (WD), as well as communication between network nodes and between WDs. The 3GPP is also developing standards for Sixth Generation (6G) wireless communication networks.

[0006] PDCCH

[0007] Downlink control information (DCI) in NR consists of, for example, scheduling grants, and is transmitted on the physical downlink control channel (PDCCH). The overall PDCCH processing in NR is illustrated in FIG. 1. The cyclic redundancy code (CRC) transmitted over the air is affected by the identity of the targeted device (or, more generally, the radio network temporary identifier (RNTI)). Thus, when decoding the control information in the wireless device WD, information intended for another WD appears as noise to the receiver, resulting in a failed CRC check and the WD taking no further action.

[0008] A PDCCH is transmitted using 1, 2, 4, 8, or 16 contiguous control-channel elements (CCEs) with the number of control -channel elements used referred to as the aggregation level. The control -channel element is the unit upon which the search spaces for blind decoding are defined as will be discussed below. A control-channel element consists of six resource-element groups (REGs), each of which is equal to one resource block (12 subcarriers) in one orthogonal frequency division multiplexed (OFDM) symbol. Demodulation reference signals (DM-RS) are also inserted in the PDCCH to support the channel estimation necessary at the WD in order to decode the PDCCH content. After accounting for the DM-RS overhead, there are 54 resource elements (108 bits) available for PDCCH transmission in one control -channel element. CORESET

[0009] Central to downlink control signaling in NR is the concept of control resource sets (CORESETs). A control resource set is a time-frequency resource in which the device tries to decode candidate control channels using one or more search spaces. The size and location of a CORESET in the time-frequency domain is semi-statically configured by the network and may thus be set to be smaller than the carrier bandwidth.

[0010] Blind decoding and search spaces

[0011] The WD attempts to blindly decode any PDCCHs, for example once per slot (other time intervals are also possible). Assuming a certain payload size (there are a small number of possible sizes) and a certain aggregation level (1, 2, 4, 8, 16 CCEs), the WD tries to decode a candidate PDCCH. If the CRC verification succeeds, the DCI is intended for this WD and the WD follows the content of the DCI. If the CRC verification does not succeed, the content was either corrupt due to disturbances on the radio channel or was intended for another WD. In either case, the WD takes no further action based on this (failed) decoding. See FIG. 2.

[0012] Blind decoding is a non-negligible processing burden for the device and large parts of the downlink control channel design are related to reducing this complexity. Two aspects to limit the blind decoding complexity is to limit the number of PDCCH candidates by restricting the location in the time-frequency domain and not allowing arbitrary aggregation levels, and to limit the set of DCI sizes to monitor.

[0013] The CCE structure provides a well-defined time-frequency structure useful to limit the number of candidates but is not sufficient. Clearly, from a scheduling point of view, restrictions in the allowed aggregation levels are undesirable as they may reduce the scheduling flexibility and require additional processing at the transmitter side. At the same time, requiring the device to monitor all possible CCE aggregations and locations in all configured CORESETs is not attractive from a device-complexity point of view. To impose as few restrictions as possible on the scheduler while at the same time limiting the maximum number of blind decoding attempts in the device, NR defines so-called search spaces. A search space is a set of candidate control channels formed by CCEs at a given aggregation level, which the device is supposed to attempt to decode. As there are multiple aggregation levels, a device may have multiple search spaces. A search space set is a set of search spaces with different aggregation levels linked to the same CORESET. Thus, by configuring a CORESET and a search space set, the device may monitor the presence of control channels with different aggregation levels using the same time-frequency resource. The purpose of the different aggregation levels is to control the code rate of the PDCCH and therefore be able to perform link adaptation of the PDCCH. The higher the aggregation level, the lower the code rate given a fixed DCI size. Thus, in poor channel conditions, the network node (e.g., a gNB) would select a higher aggregation level than in favorable channel conditions.

[0014] Upon attempting to decode a candidate PDCCH, the content of the control channel is declared valid for this device if the CRC checks and the device processes the information (scheduling assignment, scheduling grants, etc.). If the CRC does not check, the information is either subject to uncorrectable transmission errors or intended for another device and in either case the device ignores that PDCCH transmission.

[0015] Having discussed the search spaces, it is clear that the network may only address a device if the control information is transmitted on a PDCCH formed by the CCEs in one of the device’s search spaces. For example, device A in FIG. 3 cannot be addressed on a PDCCH starting at CCE number 20, whereas device B can. Furthermore, if device A is using CCEs 16-23, device B cannot be addressed on aggregation level 4 as all CCEs in its level-4 search space are blocked by being used for other devices. From this it may be intuitively understood that for efficient utilization of the CCEs in the system, the search spaces should differ between devices (except if all devices are able to monitor all CCEs which is unlikely from a complexity perspective). Each device in the system may therefore have one or more configured device-specific search spaces (also known as user equipment (UE)-specific search spaces, USS). As a device-specific search space for complexity reasons typically cannot contain all the CCEs upon which the network may transmit at the corresponding aggregation level, there should be a mechanism determining the set of CCEs in a device-specific search space.

[0016] The location of a device-specific search space, expressed as a starting CCE number, is defined without explicit signaling through a function of the C-RNTI, a device identity unique in the cell. Furthermore, the set of CCEs the device should monitor for a certain aggregation level also varies as a function of time to avoid two devices constantly blocking each other. This randomizes the location of a search space over time (with more or less independent randomization between aggregation levels). If two search spaces collide at one time instant, they are not likely to collide at the next time instant. In each of these search spaces, the device is attempting to decode the PDCCHs using the device-specific C-RNTI identity. If valid control information is found, for example a scheduling grant, the device acts accordingly.

[0017] To limit the complexity of the blind decodings in the device, NR has (among other things) introduced limitations on:

[0018] • The number of blind decoding attempts. For 15 / 30 / 60 / 120 kHz subcarrier spacing, up to 44 / 36 / 22 / 20 blind decoding attempts per slot may be supported across all DCI sizes; and

[0019] • The number of channel estimates. The number of channel estimates for subcarrier spacings of 15 / 30 / 60 / 120 kHz has been limited to 56 / 56 / 48 / 32 non-overlapping CCEs across all CORESETs in a slot. In the example of FIG. 3, device A must perform channel estimates for 30 nonoverlapping CCEs (6-35) whereas device B must perform channel estimates for 40 non-overlapping CCEs (0-39).

[0020] Depending on the configuration, the number of PDCCH candidates may be limited either by the number of blind decodes, or by the number of channel estimates. CRC checking is of low complexity so monitoring multiple RNTIs all with the same payload size is not costly and almost comes “for free”.

[0021] The limit on the number of channel estimates in NR may lead to not all blind decoding attempts being used in some slots. Even if additional users may be scheduled from a user data perspective (there is capacity available for data transmission), and even if there are sufficiently many unused CCEs to satisfy the aggregation level for a given WD, there might not be any PDCCHs available to schedule that WD. Hence, PDCCH may become a capacity bottleneck.

[0022] For example, assume that a CORESET of 36 CCE is configured and two search space with [5, 4, 1, 1, 1] candidates of aggregation levels [1, 2, 4, 8, 16] is associated with the CORESET in first and second OFDM symbols of the slot. The number of search spaces that the WD monitors in each slot is depicted in FIG. 4. Observe that given the search-space randomization over time as specified for NR, together with the CCE constraint, the second search space is not decoded at all in some slots. Note that there are only 24 candidates in total (the limit is 44 for subcarrier spacing (SCS) 15 kHz). This results in unbalanced and uncontrolled PDCCH capacity. The alternative is to configure candidates in a conservative manner to ensure that the CCE constraint will not be reached. But this results in inefficient use of resources and degradation of PDCCH capacity. SUMMARY

[0023] Some embodiments advantageously provide methods, systems, and apparatuses for improved control channel element (CCE) randomization.

[0024] In some embodiments, search space randomization is performed such that no blind decode is located outside the CCEs covered by channel estimation. In some embodiments, blind decoding attempts that would be blocked due to the limit on the maximum number of channel estimates are remapped to CCEs which are within the limits, i.e., on which the WD performs channel estimates for another (typically higher) aggregation level.

[0025] In some embodiments, a method is provided for increasing the number of usable search spaces taking the maximum number of supported channel estimates and blind decodes into account.

[0026] Some embodiments provide a lower likelihood of the system capacity being limited by the PDCCH capacity.

[0027] According to one aspect, a method in a wireless device, WD, configured to communicate with a network node is provided. The method includes mapping a search space to a set of non-overlapping control channel elements, CCEs, when the WD supports additional non-overlapping CCEs for a given CCE aggregation level. The method also includes mapping a search space to a set of overlapped CCEs when the WD does not support the additional non-overlapping CCEs. The method further includes, otherwise, when the set of overlapped CCEs has a cardinality less than the aggregation level of a candidate control channel, then not mapping the search space.

[0028] According to this aspect, in some embodiments, the method includes randomizing N channel estimates across all CCEs in a control resource set, CORESET, N being a number of channel estimates the WD is capable of performing. In some embodiments, the method includes randomizing blind decodings for a subset of CCEs for which channel estimates are performed. In some embodiments, the method includes randomly selecting L CCEs, L being equal to a 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 been performed. In some embodiments, when not all CCE aggregation levels have been mapped, mapping the search space for a next lower aggregation level. In some embodiments, the search space is mapped in a decreasing order of CCE aggregation levels. In some embodiments, the method includes randomizing blind decodings for each of a number of channel estimates performed by the WD. In some embodiments, the method includes mapping a remaining set of blind decodings to CCEs of the given CCE aggregation level. In some embodiments, a location of control resource sets, CORESETs, are randomized. In some embodiments, the method includes assuming a random mapping of physical downlink control channels, PDCCHs, and finding corresponding CCE indices for CCEs in a CCE aggregation level. In some embodiments, finding corresponding indices for CCEs in a CCE aggregation level is performed for each of a plurality of CCE aggregation levels.

[0029] 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 control channel elements, CCEs, when the WD supports additional non-overlapping CCEs for a given CCE aggregation level. The processing circuitry is configured to map a search space to a set of overlapped CCEs when the WD does not support the additional non-overlapping CCEs; and otherwise, when the set of overlapped CCEs has a cardinality less than the aggregation level of a candidate control channel, then not map the search space.

[0030] According to this aspect, in some embodiments the processing circuitry is further configured to randomize N channel estimates across all CCEs in a control resource set, CORESET, N being a number of channel estimates the WD is capable of performing. In some embodiments, the processing circuitry is further configured to randomize blind decodings for a subset of CCEs for which channel estimates are performed. In some embodiments, the processing circuitry is further configured to randomly select L CCEs, L being equal to a 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 estimates have not been performed. In some embodiments, when not all CCE aggregation levels have been mapped, mapping the search space for a next lower aggregation level. In some embodiments, the search space is mapped in a decreasing order of aggregation levels. In some embodiments, the processing circuitry is further configured to randomize blind decodings for each of a number of channel estimates performed by the WD. In some embodiments, the processing circuitry is further configured to map a remaining set of blind decodings to CCEs of the given CCE aggregation level. In some embodiments, a location of control resource sets, CORESETs, are randomized. In some embodiments, the processing circuitry is further configured to assume a random mapping of physical downlink control channels, PDCCHs, and to find corresponding CCE indices for CCEs in a CCE aggregation level. In some embodiments, finding corresponding indices for CCEs in a CCE aggregation level is performed for each of a plurality of CCE aggregation levels.

[0031] BRIEF DESCRIPTION OF THE DRAWINGS

[0032] A more complete understanding of the present embodiments, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

[0033] FIG. 1 illustrates PDCCH processing;

[0034] FIG. 2 illustrates blind decoding in a WD:

[0035] FIG. 3 is an example of search spaces for two different WDs;

[0036] FIG. 4 illustrates that a search space may violate CCE constraints

[0037] FIG. 5 is a schematic diagram of an example network architecture illustrating a communication system connected via an intermediate network to a host computer according to the principles in the present disclosure;

[0038] FIG. 6 is a block diagram of a host computer communicating via a network node with a wireless device over an at least partially wireless connection according to some embodiments of the present disclosure;

[0039] FIG. 7 is a flowchart illustrating example methods implemented in a communication system including a host computer, a network node and a wireless device for executing a client application at a wireless device according to some embodiments of the present disclosure;

[0040] FIG. 8 is a flowchart illustrating example methods implemented in a communication system including a host computer, a network node and a wireless device for receiving user data at a wireless device according to some embodiments of the present disclosure;

[0041] FIG. 9 is a flowchart illustrating example methods implemented in a communication system including a host computer, a network node and a wireless device for receiving user data from the wireless device at a host computer according to some embodiments of the present disclosure; FIG. 10 is a flowchart illustrating example methods implemented in a communication system including a host computer, a network node and a wireless device for receiving user data at a host computer according to some embodiments of the present disclosure;

[0042] FIG. 11 is a flowchart of an example process in a wireless device for improved control channel element (CCE) randomization;

[0043] FIG. 12 is an example of CCE mapping;

[0044] FIG. 13 illustrates how a CORESET location may be randomly mapped;

[0045] FIG. 14 illustrates how WD may be grouped in different frequency locations; and

[0046] FIGS. 15A and 15B illustrate an example of a comparison of resultant search spaces for a legacy systems and some embodiments disclosed herein.

[0047] DETAILED DESCRIPTION

[0048] Before describing in detail example embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to improved control channel element (CCE) randomization. Accordingly, components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Like numbers refer to like elements throughout the description.

[0049] As used herein, relational terms, such as “first” and “second,” “top” and “bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying 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 be limiting of the concepts described herein. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and / or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. In embodiments described herein, the joining term, “in communication with” and the like, may be used to indicate electrical or data communication, which may be accomplished by physical contact, induction, electromagnetic radiation, radio signaling, infrared signaling or optical signaling, for example. One having ordinary skill in the art will appreciate that multiple components may interoperate and modifications and variations are possible of achieving the electrical and data communication.

[0050] In some embodiments described herein, the term “coupled,” “connected,” and the like, may be used herein to indicate a connection, although not necessarily directly, and may include wired and / or wireless connections.

[0051] The term “network node” used herein may be any kind of network node comprised in a radio network which may further comprise any of 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 controlling relay, radio access point (AP), transmission points, transmission nodes, Remote Radio Unit (RRU) Remote Radio Head (RRH), a core network node (e.g., mobile management entity (MME), self-organizing network (SON) node, a coordinating node, positioning node, MDT node, etc.), an external node (e.g., 3rd party node, a node external to the current network), nodes in distributed antenna system (DAS), a spectrum access system (SAS) node, an element management system (EMS), etc. The network node may also comprise test equipment. The term “radio node” used herein may be used to also denote a wireless device (WD) such as a wireless device (WD) or a radio network node.

[0052] In some embodiments, the non-limiting terms wireless device (WD) or a user equipment (UE) are used interchangeably. The WD herein may be any type of wireless device capable of communicating with a network node or another WD over radio signals, such as wireless device (WD). The WD may also be a radio communication device, target device, device to device (D2D) WD, machine type WD or WD capable of machine to machine communication (M2M), low-cost and / or low-complexity WD, a sensor equipped with WD, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), an Internet of Things (loT) device, or a Narrowband loT (NB-IOT) device, etc. Also, in some embodiments the generic term “radio network node” is used. It may be any kind of a radio network node which may comprise any of 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) Remote Radio Head (RRH).

[0053] Note that although terminology from one particular wireless system, such as, for example, 3GPP LTE and / or New Radio (NR), may be used in this disclosure, this should not be seen as limiting the scope of the disclosure to only the aforementioned system. Other wireless systems, including without limitation Wide Band Code Division Multiple Access (WCDMA), Worldwide Interoperability for Microwave Access (WiMax), Ultra Mobile Broadband (UMB) and Global System for Mobile Communications (GSM), may also benefit from exploiting the ideas covered within this disclosure.

[0054] Note further, that functions described herein as being performed by a wireless device or a network node may be distributed over a plurality of wireless devices and / or network nodes. In other words, it is contemplated that the functions of the network node and wireless device described herein are not limited to performance by a single physical device and, in fact, may be distributed among several physical devices.

[0055] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0056] Some embodiments provide improved control channel element (CCE) randomization.

[0057] Returning now to the drawing figures, in which like elements are referred to by like reference numerals, there is shown in FIG. 5 a schematic diagram of a communication system 10, according to an embodiment, such as a 3 GPP -type cellular network that may support standards such as LTE and / or NR (5G), which comprises an access network 12, such as a radio access network, and a core network 14. The access network 12 comprises a plurality of network nodes 16a, 16b, 16c (referred to collectively 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 (referred to collectively as coverage areas 18). Each network node 16a, 16b, 16c is connectable to the core network 14 over 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 is wirelessly connectable to the corresponding network node 16b. While a plurality of WDs 22a, 22b (collectively referred to as wireless devices 22) are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole WD is in the coverage area or where a sole WD is connecting to the corresponding network node 16. Note that although only two WDs 22 and three network nodes 16 are shown for convenience, the communication system may include many more WDs 22 and network nodes 16.

[0058] Also, it is contemplated that a WD 22 may be in simultaneous communication and / or configured to separately communicate with more than one network node 16 and more than one type of network node 16. For example, a WD 22 may have dual connectivity with a network node 16 that supports LTE and the same or a different network node 16 that supports NR. As an example, WD 22 may be in communication with an eNB for LTE / E-UTRAN and a gNB for NR / NG-RAN.

[0059] The communication system 10 may itself be connected to a host computer 24, which may be embodied in the hardware and / or software of a standalone server, a cloud-implemented server, a distributed server or as processing resources in a server farm. The host computer 24 may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider. The connections 26, 28 between the communication system 10 and the host computer 24 may extend directly from the core network 14 to the host computer 24 or may extend via an optional intermediate network 30. The intermediate network 30 may be one of, or a combination of more than one of, a public, private or hosted network. The intermediate network 30, if any, may be a backbone network or the Internet. In some embodiments, the intermediate network 30 may comprise two or more subnetworks (not shown).

[0060] The communication system of FIG. 5 as a whole enables connectivity between one of the connected WDs 22a, 22b and the host computer 24. The connectivity may be described as an over-the-top (OTT) connection. The host computer 24 and the connected WDs 22a, 22b are configured to communicate data and / or signaling via the OTT connection, using the access network 12, the core network 14, any intermediate network 30 and possible further infrastructure (not shown) as intermediaries. The OTT connection may be transparent in the sense that at least some of the participating communication devices through which the OTT connection passes are unaware of routing of uplink and downlink communications. For example, a network node 16 may not or need not be informed about the past routing of an incoming downlink communication with data originating from a host computer 24 to be forwarded (e.g., handed over) to a connected WD 22a. Similarly, the network node 16 need not be aware of the future routing of an outgoing uplink communication originating from the WD 22a towards the host computer 24.

[0061] A wireless device 22 is configured to include a CCE unit 34 which may be configured to map a search space to a set of control channel elements based at least in part on a number of overlapping CCEs and a CCE aggregation level.

[0062] Example implementations, in accordance with an embodiment, of the WD 22, network node 16 and host computer 24 discussed in the preceding paragraphs will now be described with reference to FIG. 5. In a communication system 10, a host computer 24 comprises hardware (HW) 38 including a communication interface 40 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system 10. The host computer 24 further comprises processing circuitry 42, which may have storage and / or processing capabilities. The processing circuitry 42 may include a processor 44 and memory 46. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 42 may comprise integrated circuitry for processing and / or control, e.g., one or more processors and / or processor cores and / or FPGAs (Field Programmable Gate Array) and / or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 44 may be configured to access (e.g., write to and / or read from) memory 46, which may comprise any kind of volatile and / or nonvolatile memory, e.g., 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).

[0063] Processing circuitry 42 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, e.g., by host computer 24. Processor 44 corresponds to one or more processors 44 for performing host computer 24 functions described herein. The host computer 24 includes memory 46 that is configured to store data, programmatic software code and / or other information described herein. In some embodiments, the software 48 and / or the host application 50 may include instructions that, when executed by the processor 44 and / or processing circuitry 42, causes the 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 the host computer 24.

[0064] The software 48 may be executable by the processing circuitry 42. The software 48 includes a host application 50. The host application 50 may be operable to provide a service to a remote user, such as a WD 22 connecting via an OTT connection 52 terminating at the WD 22 and the host computer 24. In providing the service to the remote user, the host application 50 may provide user data which is transmitted using the OTT connection 52. The “user data” may be data and information described herein as implementing the described functionality. In one embodiment, the host computer 24 may be configured for providing control and functionality to a service provider and may be operated by the service provider or on behalf of the service provider. The processing circuitry 42 of the host computer 24 may enable the host computer 24 to observe, monitor, control, transmit to and / or receive from the network node 16 and or the wireless device 22.

[0065] The communication system 10 further includes a network node 16 provided in a communication system 10 and including hardware 58 enabling it to communicate with the host computer 24 and with the WD 22. The hardware 58 may include a communication interface 60 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 10, as well as a radio interface 62 for setting up and maintaining at least a wireless connection 64 with a WD 22 located in a coverage area 18 served by the network node 16. The radio interface 62 may be formed 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 pass through a core network 14 of the communication system 10 and / or through one or more intermediate networks 30 outside the communication system 10.

[0066] In the embodiment shown, the hardware 58 of the network node 16 further includes processing circuitry 68. The processing circuitry 68 may include a processor 70 and a memory 72. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 68 may comprise integrated circuitry for processing and / or control, e.g., one or more processors and / or processor cores and / or FPGAs (Field Programmable Gate Array) and / or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 70 may be configured to access (e.g., write to and / or read from) the memory 72, which may comprise any kind of volatile and / or nonvolatile memory, e.g., 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).

[0067] Thus, the network node 16 further has software 74 stored internally in, for example, memory 72, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the network node 16 via an external connection. The software 74 may be executable by the processing circuitry 68. The processing circuitry 68 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, e.g., by network node 16. Processor 70 corresponds to one or more processors 70 for performing network node 16 functions described herein. The memory 72 is configured to store data, programmatic software code and / or other information described herein. In some embodiments, the software 74 may include instructions that, when executed by the processor 70 and / or processing circuitry 68, causes the processor 70 and / or processing circuitry 68 to perform the processes described herein with respect to network node 16.

[0068] The communication system 10 further includes the WD 22 already referred to. The WD 22 may have hardware 80 that may include a radio interface 82 configured to set up and maintain a wireless connection 64 with a network node 16 serving a coverage area 18 in which the WD 22 is currently located. The radio interface 82 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and / or one or more RF transceivers.

[0069] The hardware 80 of the WD 22 further includes processing circuitry 84. The processing circuitry 84 may include a processor 86 and memory 88. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 84 may comprise integrated circuitry for processing and / or control, e.g., one or more processors and / or processor cores and / or FPGAs (Field Programmable Gate Array) and / or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 86 may be configured to access (e.g., write to and / or read from) memory 88, which may comprise any kind of volatile and / or nonvolatile memory, e.g., 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).

[0070] Thus, the WD 22 may further comprise software 90, which is stored in, for example, memory 88 at the WD 22, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the WD 22. The software 90 may be executable by the processing circuitry 84. The software 90 may include a client application 92. The client application 92 may be operable to provide a service to a human or non-human user via the WD 22, with the support of the host computer 24. In the host computer 24, an executing host application 50 may communicate with the executing client application 92 via the OTT connection 52 terminating at the WD 22 and the host computer 24. In providing the service to the user, the client application 92 may receive request data from the host application 50 and provide user data in response to the request data. The OTT connection 52 may transfer both the request data and the user data. The client application 92 may interact with the user to generate the user data that it provides.

[0071] The 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, e.g., by WD 22. The processor 86 corresponds to one or more processors 86 for performing WD 22 functions described herein. The WD 22 includes memory 88 that is configured to store data, programmatic software code and / or other information described herein. In some embodiments, the software 90 and / or the client application 92 may include instructions that, when executed by the processor 86 and / or processing circuitry 84, causes the processor 86 and / or processing circuitry 84 to perform the processes described herein with respect to WD 22. For example, the processing circuitry 84 of the wireless device 22 may include a CCE unit 34 which may be configured to map a search space to a set of control channel elements based at least in part on a number of overlapping CCEs and a CCE aggregation level.

[0072] In some embodiments, the inner workings of the network node 16, WD 22, and host computer 24 may be as shown in FIG. 6 and independently, the surrounding network topology may be that of FIG. 5. In FIG. 6, the OTT connection 52 has been drawn abstractly to illustrate the communication between the host computer 24 and the wireless device 22 via the network node 16, without explicit reference to any intermediary devices and the precise routing of messages via these devices. Network infrastructure may determine the routing, which it may be configured to hide from the WD 22 or from the service provider operating the host computer 24, or both. While the OTT connection 52 is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network).

[0073] The wireless connection 64 between the WD 22 and the network node 16 is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the WD 22 using the OTT connection 52, in which the wireless connection 64 may form the last segment. More precisely, the teachings of some of these embodiments may improve the data rate, latency, and / or power consumption and thereby provide benefits such as reduced user waiting time, relaxed restriction on file size, better responsiveness, extended battery lifetime, etc.

[0074] In some embodiments, a measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 52 between the host computer 24 and WD 22, in response to variations in the measurement results. The measurement procedure and / or the network functionality for reconfiguring the OTT connection 52 may be implemented in the software 48 of the host computer 24 or in the software 90 of the WD 22, or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which the OTT connection 52 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software 48, 90 may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 52 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect the network node 16, and it may be unknown or imperceptible to the network node 16. Some such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary WD signaling facilitating the host computer’s 24 measurements of throughput, propagation times, latency and the like. In some embodiments, the measurements may be implemented in that the software 48, 90 causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection 52 while it monitors propagation times, errors, etc.

[0075] Thus, in some embodiments, the host computer 24 includes processing circuitry 42 configured to provide user data and a communication interface 40 that is configured to forward the user data to a cellular network for transmission to the WD 22. In some embodiments, the cellular network also includes the network node 16 with a radio interface 62. In some embodiments, the network node 16 is configured to, and / or the network node’s 16 processing circuitry 68 is configured to perform the functions and / or methods described herein for preparing / initiating / maintaining / supporting / ending a transmission to the WD 22, and / or preparing / terminating / maintaining / supporting / ending in receipt of a transmission from the WD 22.

[0076] In some embodiments, the host computer 24 includes processing circuitry 42 and a communication interface 40 that is configured to a communication interface 40 configured to receive user data originating from a transmission from a WD 22 to a network node 16. In some embodiments, the WD 22 is configured to, and / or comprises a radio interface 82 and / or processing circuitry 84 configured to perform the functions and / or methods described herein for preparing / initiating / maintaining / supporting / ending a transmission to the network node 16, and / or preparing / terminating / maintaining / supporting / ending in receipt of a transmission from the network node 16.

[0077] Although FIGS. 5 and 6 show various “units” such as CCE unit 34 as being within a respective processor, it is contemplated that these units may be implemented such that a portion of the unit is stored in a corresponding memory within the processing circuitry. In other words, the units may be implemented in hardware or in a combination of hardware and software within the processing circuitry.

[0078] FIG. 7 is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of FIGS. 5 and 2, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIG. 6. In a first step of the method, the host computer 24 provides user data (Block SI 00). In an optional substep of the first step, the host computer 24 provides the user data by executing a host application, such as, for example, the host application 50 (Block SI 02). In a second step, the host computer 24 initiates a transmission carrying the user data to the WD 22 (Block SI 04). In an optional third step, the network node 16 transmits to the WD 22 the user data which was carried in the transmission that the host computer 24 initiated, in accordance with the teachings of the embodiments described throughout this disclosure (Block SI 06). In an optional fourth step, the WD 22 executes a client application, such as, for example, the client application 92, associated with the host application 50 executed by the host computer 24 (Block SI 08).

[0079] FIG. 8 is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of FIG. 5, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIGS. 5 and 6. In a first step of the method, the host computer 24 provides user data (Block SI 10). In an optional substep (not shown) the host computer 24 provides the user data by executing a host application, such as, for example, the host application 50. In a second step, the host computer 24 initiates a transmission carrying the user data to the WD 22 (Block SI 12). The transmission may pass via the network node 16, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional third step, the WD 22 receives the user data carried in the transmission (Block SI 14).

[0080] FIG. 9 is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of FIG. 5, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIGS. 5 and 6. In an optional first step of the method, the WD 22 receives input data provided by the host computer 24 (Block SI 16). In an optional substep of the first step, the WD 22 executes the client application 92, which provides the user data in reaction to the received input data provided by the host computer 24 (Block SI 18). Additionally or alternatively, in an optional second step, the WD 22 provides user data (Block S120). In an optional substep of the second step, the WD provides the user data by executing a client application, such as, for example, client application 92 (Block S122). In providing the user data, the executed client application 92 may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the WD 22 may initiate, in an optional third substep, transmission of the user data to the host computer 24 (Block S124). In a fourth step of the method, the host computer 24 receives the user data transmitted from the WD 22, in accordance with the teachings of the embodiments described throughout this disclosure (Block s 126).

[0081] FIG. 10 is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of FIG. 5, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIGS. 5 and 6. In an optional first step of the method, in accordance with the teachings of the embodiments described throughout this disclosure, the network node 16 receives user data from the WD 22 (Block S128). In an optional second step, the network node 16 initiates transmission of the received user data to the host computer 24 (Block SI 30). In a third step, the host computer 24 receives the user data carried in the transmission initiated by the network node 16 (Block SI 32).

[0082] FIG. 11 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 may be performed by one or more elements of wireless device 22 such as by one or more of processing circuitry 84 (including the CCE unit 34), processor 86, radio interface 82 and / or communication interface 60. Wireless device 22 such as via processing circuitry 84 and / or processor 86 and / or radio interface 82 is configured to map a search space to a set of non-overlapping control channel elements, CCEs, when the WD supports additional non-overlapping CCEs for a given CCE aggregation level (Block SI 34). The method also includes mapping a search space to a set of overlapped CCEs when the WD 22 does not support the additional non-overlapping CCEs (Block S136). The method further includes, otherwise, when the set of overlapped CCEs has a cardinality less than the aggregation level of a candidate control channel, then not mapping the search space (Block S138).

[0083] In some embodiments, the method includes randomizing N channel estimates across all CCEs in a control resource set, CORESET, N being a number of channel estimates the WD 22 is capable of performing. In some embodiments, the method includes randomizing blind decodings for a subset of CCEs for which channel estimates are performed. In some embodiments, the method includes randomly selecting L CCEs, L being equal to a 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 been performed. In some embodiments, when not all CCE aggregation levels have been mapped, mapping the search space for a next lower aggregation level. In some embodiments, the search space is mapped in a decreasing order of CCE aggregation levels. In some embodiments, the method includes randomizing blind decodings for each of a number of channel estimates performed by the WD 22. In some embodiments, the method includes mapping a remaining set of blind decodings to CCEs of the given CCE aggregation level. In some embodiments, a location of control resource sets, CORESETs, are randomized. In some embodiments, the method includes assuming a random mapping of physical downlink control channels, PDCCHs, and finding corresponding CCE indices for CCEs in a CCE aggregation level. In some embodiments, finding corresponding indices for CCEs in a CCE aggregation level is performed for each of a plurality of CCE aggregation levels.

[0084] Having described the general process flow of arrangements of the disclosure and having provided examples of hardware and software arrangements for implementing the processes and functions of the disclosure, the sections below provide details and examples of arrangements for improved control channel element (CCE) randomization.

[0085] In some embodiments, search space randomization is performed such that no blind decode is dropped or skipped due to the limited channel estimates. Some embodiments ensure that the full blind decoding capability is used despite limitations given by the number of channel estimates. In some embodiments, PDCCH candidate mapping is performed while taking the number of available channel estimates into account.

[0086] Variant A - Select CCEs with channel estimates first and map blind decodes afterwards

[0087] Example embodiment 1

[0088] In some embodiments, a method is provided where each search space (in decreasing order of aggregation levels) is mapped to a set of non-overlapping CCEs if the WD 22 supports the additional set of non-overlapping CCEs required for the search space’s aggregation level. The search space is otherwise mapped to CCEs selected only for a search space of a higher aggregation level. The search space is otherwise skipped. In some embodiments, supporting an additional set of non-overlapping CCEs includes supporting additional channel estimations for the non-overlappng CCEs.

[0089] Example embodiment 2 In some embodiments, channel estimates are randomized across all CCEs in the CORESET, then blind decodings are randomized within the subset of CCEs with channel estimates.

[0090] In some embodiments, one or more of the following steps prioritize the highest aggregation levels. Other possibilities exist.

[0091] 1. Let S=all CCEs in the CORESET;

[0092] 2. Let C = {} (the empty set);

[0093] 3. Let N=number of channel estimates the WD 22 is capable of, or allowed to use for this search space set, expressed in CCEs;

[0094] 4. Let L=highest aggregation level configured [in the search space set];

[0095] 5. If at least one of a, b, or (optionally) c below are fulfilled, goto 10; a. N<L; or b. it is not possible to find L consecutive CCEs in S; or c. the number of CCEs with channel estimates already obtained at aggregation level L are sufficient to handle the number of PDCCH candidate at this aggregation level;

[0096] 6. (randomly) select L (consecutive) CCEs in S for channel estimation, add these CCEs to the set C. (The selection of L CCEs may be performed according to a hash function of a pseudo-random sequence or other means as long as the network node 16 and the WD 22 has the same understanding of which CCEs that are selected.);

[0097] 7. S = S \ C (i.e. S is the remaining CCEs not yet with channel estimates);

[0098] 8. N=N-L (i.e. subtract the number of CCEs not selected in the previous step, the expression works for the CCE definition used in NR);

[0099] 9. Goto 5;

[0100] 10. If not all aggregation levels have been considered and N>0: set L = next lower aggregation level, goto 5;

[0101] 11. The set C contains the CCEs with channel estimates; and / or

[0102] 12. Randomize search spaces for blind decoding within the set C, e.g. using a similar equation as in 3GPP Release-15 Technical Standard (TS) 38.213. Variant B - select blind decodes first, change selection strategy if the channel estimate limit is reached

[0103] Example embodiment 3

[0104] Some embodiments include a method where each search space (in decreasing order of aggregation levels) is mapped to CCEs selected only for a search space of a higher aggregation level (if any) and where the search space is otherwise mapped to a set of non-overlapping CCEs if the WD 22 supports the additional set of nonoverlapping CCEs required for the search space’s aggregation level. Otherwise, the search space candidate is skipped.

[0105] Example embodiment 4

[0106] Some embodiments include a method where randomized blind decoding is performed as in NR (or some variant thereof) until the limit set by the number of channel estimates is reached. Remaining blind decodings may be mapped to CCEs already covered by larger aggregation levels (and not already having a blind decoding of the same aggregation level), as shown in FIG. 12.

[0107] One example process includes one or more of the following steps.

[0108] 1. Generate M top level candidates (i.e. the aggregation level is the largest aggregation level configured for this search space set) using the formula from 3GPP Release-15 TS 38.213, section 10.1;

[0109] 2. For each top level candidate mi, generate M_mi subcandidates using the same formula but with Ncce = L_mi where L_mi is the aggregation level of mi; and / or

[0110] 3. Add the start CCE index of mi to each subcandidate mij of mi generated in step 2.

[0111] Example embodiment 5

[0112] In some embodiments, the location of the CORESET is randomized. To control the number of channel estimations performed by the WD 22, the network node 16 may configure a smaller CORESET. This results in PDCCH candidates overlapping more frequently and thus reduces the number of channel estimations. However, this also increases the chance of WDs 22 blocking each other. To reduce the chance that all WDs 22 have their candidates in the CORESET (with reduced size), in some embodiments, the location of CORESET for each WD 22 is also randomized. This method creates a grouping strategy for the WDs 22 by mapping their CORESET in random locations in the frequency domain. Instead of configuring an exact location of the CORESET, in some embodiments, only the size of (how many CCEs) the CORSET is defined. An offset, o, is defined to control where the CORESET is mapped in the frequency domain. Particularly, the location of the CORESET in the frequency domain then may be calculated. The CORESET may occupy the frequency domain (o, (o + CORESET size) mod CarrierBandwidth) (the modulo operation being optional). The variable o may be a random function that is generated by another hash function known to both WD 22 and network node 16. In some embodiments, the o may refer to a physical resource block (PRB) in the resource grid or a subcarrier index or a group of PRBs.

[0113] An example random CORESET mapping is illustrated in FIG. 13

[0114] The grouping of the WDs 22 into different parts of the frequency domain resources in illustrated in FIG. 14. FIG. 14 illustrates how WDs 22 are grouped in different frequency locations. There are 15 WDs 22 in this example. The numbers, in the bracket indicates the indices of the WDs 22.

[0115] Example embodiment 6

[0116] In some embodiments, the procedure for performing the blind decoding is enhanced so that no PDCCH candidate is ignored because of the number of nonoverlapping CCE limitations. One example process may include one or more of the following steps.

[0117] (step 1) First the WD 22 may assume that the randomization mapping of candidates into the CCEs (as configured in the CORESET) is done as in NR. The WD 22 starts from the highest aggregation level candidates and finds the corresponding CCE indexes for the candidates in that aggregation level. Then the number of NO- CCEs is calculated. Then this is repeated for other aggregation levels. At any point in time, if the number of NO-CCE is larger than a limit the procedure stops. The limit is either set by the maximum number of NO-CCE blind decodings the WD 22 may perform, as set forth in standards specifications or a number that is configured by the network when search spaces are configured. In some embodiments, this may be realized to introduce the filed in “SearchSpace” information element (IE) in 3GPP TS 38.331. If not configured, the WD 22 may assume a default value that is either introduced in standards specifications or is configured; and or

[0118] (step 2) At this point, the WD 22 has recorded a set of CCE indices that has been already visited. Next, for the remainder of the candidates, instead of using the original CCE indices (as configured), the WD 22 uses the set of CCE indices in step 1 as input to the randomization function in NR.

[0119] The following example shows a benefit of the solutions disclosed herein. Assume that there are two search spaces sets configured. When the WD 22 performs blind decoding for the common search space and the first search space set, the WD 22 performs channel estimation for 40 NO-CCE. Hence, for the second search space, the WD 22 may only perform channel estimation for 16 NO-CCE. In this example, it is assumed that the second search space has [6, 4, 4, 2, 1] candidates of aggregation levels [1, 2, 4, 8, 16],

[0120] FIGS. 15A and 15B are an example of an illustration of how some embodiments improve upon the legacy procedure. FIG. 15A shows that performing the blind decoding on this search space may require channel estimation on 34 NO-CCEs which is more than the budget. Thus, it may not be possible to decode any candidate and the whole search space is ignored by the WD 22. FIG. 15B shows an advantage of some embodiments. Similar to legacy systems, decoding of the second aggregation level 8 candidate would violate the constraint but in some embodiments disclosed herein, the other candidates are mapped into already visited CCEs (CCEs 16, 17, . . . , 31 in FIG. 8) and no candidates are lost.

[0121] Some embodiments may be incorporated into section 10.1 of 3GPP Release-15 TS 38.213 when added to NR and in corresponding sections of 6G standards.

[0122] As will be appreciated by one of skill in the art, the concepts described herein may be embodied as a method, data processing system, computer program product and / or computer storage media storing an executable computer program. Accordingly, the concepts described herein may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects all generally referred to herein as a “circuit” or “module.” Any process, step, action and / or functionality described herein may be performed by, and / or associated to, a corresponding module, which may be implemented in software and / or firmware and / or hardware. Furthermore, the disclosure may take the form of a computer program product on a tangible computer usable storage medium having computer program code embodied in the medium that may be executed by a computer. Any suitable tangible computer readable medium may be utilized including hard disks, CD- ROMs, electronic storage devices, optical storage devices, or magnetic storage devices. 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, may be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer (to thereby create a special purpose computer), 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 means for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0123] These computer program instructions may also be stored in a computer readable memory or storage medium that may direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instruction means which implement the function / act specified in the flowchart and / or block diagram block or blocks.

[0124] The 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 / acts specified in the flowchart and / or block diagram block or blocks.

[0125] It is to be understood that the functions / acts noted in the blocks may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality / acts involved. Although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows.

[0126] Computer program code for carrying out operations of the concepts described herein may be written in an object oriented programming language such as Python, Java® or C++. However, the computer program code for carrying out operations of the disclosure may also be written in conventional procedural programming languages, such as the "C" programming language. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer. In the latter scenario, the remote computer may be connected to the user's computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0127] Many different embodiments have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, all embodiments may be combined in any way and / or combination, and the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and subcombinations of the embodiments described herein, and of the manner and process of making and using them, and shall support claims to any such combination or subcombination.

[0128] Abbreviations that may be used in the preceding description include:

[0129] CCE Control Channel Element

[0130] CORESET Core Resource Set

[0131] PDCCH Physical Downlink Control Channel

[0132] REG Resource Element Group

[0133] It will be appreciated by persons skilled in the art that the embodiments described herein are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the scope of the following claims.

Claims

What is claimed is:

1. A method in a wireless device, WD (22), configured to communicate with a network node (16), the method comprising: mapping (SI 34) a search space to a set of non-overlapping control channel elements, CCEs, when the WD (22) supports additional non-overlapping CCEs for a given CCE aggregation level; mapping (SI 36) a search space to a set of overlapped CCEs when the WD (22) does not support the additional non-overlapping CCEs; and otherwise, when the set of overlapped CCEs has a cardinality less than the aggregation level of a candidate control channel, then not mapping (SI 38) the search space.

2. The method of Claim 1, further comprising randomizing N channel estimates across all CCEs in a control resource set, CORESET, N being a number of channel estimates the WD (22) is capable of performing.

3. The method of Claim 2, further comprising randomizing blind decodings for a subset of CCEs for which channel estimates are performed.

4. The method of any of Claims 2 and 3, further comprising randomly selecting L CCEs, L being equal to a highest aggregation level configured in the search space.

5. The method of any of Claims 1-4, further comprising determining a set C of remaining CCEs for which channel estimates have not been performed.

6. The method of any of Claims 1-5, wherein, when not all CCE aggregation levels have been mapped, mapping the search space for a next lower aggregation level.

7. The method of any of Claims 1-6, wherein the search space is mapped in a decreasing order of CCE aggregation levels.

8. The method of any of Claims 1-7, further comprising randomizing blind decodings for each of a number of channel estimates performed by the WD (22).

9. The method of Claim 8, further comprising mapping a remaining set of blind decodings to CCEs of the given CCE aggregation level.

10. The method of any of Claims 1-9, wherein a location of control resource sets, CORESETs, are randomized.

11. The method of any of Claims 1-10, further comprising assuming a random mapping of physical downlink control channels, PDCCHs, and finding corresponding CCE indices for CCEs in a CCE aggregation level.

12. The method of Claim 11, wherein finding corresponding indices for CCEs in a CCE aggregation level is performed for each of a plurality of CCE aggregation levels.

13. A wireless device, WD (22), configured to communicate with a network node (16), the WD (22) comprising processing circuitry (82) configured to: map a search space to a set of non-overlapping control channel elements, CCEs, when the WD (22) supports additional non-overlapping CCEs for a given CCE aggregation level; map a search space to a set of overlapped CCEs when the WD (22) does not support the additional non-overlapping CCEs; and otherwise, when the set of overlapped CCEs has a cardinality less than the aggregation level of a candidate control channel, then not map the search space.

14. The WD (22) of Claim 13, wherein the processing circuitry (82) is further configured to randomize N channel estimates across all CCEs in a control resource set, CORESET, N being a number of channel estimates the WD (22) is capable of performing.

15. The WD (22) of Claim 14, wherein the processing circuitry (82) is further configured to randomize blind decodings for a subset of CCEs for which channel estimates are performed.

16. The WD (22) of any of Claims 14 and 15, wherein the processing circuitry (82) is further configured to randomly select L CCEs, L being equal to a highest aggregation level configured in the search space.

17. The WD (22) of any of Claims 13-16, wherein the processing circuitry (82) is further configured to determine a set C of remaining CCEs for which channel estimates have not been performed.

18. The WD (22) of any of Claims 13-17, wherein, when not all CCE aggregation levels have been mapped, mapping the search space for a next lower aggregation level.

19. The WD (22) of any of Claims 13-18, wherein the search space is mapped in a decreasing order of aggregation levels.

20. The WD (22) of any of Claims 13-19, wherein the processing circuitry (82) is further configured to randomize blind decodings for each of a number of channel estimates performed by the WD (22).

21. The WD (22) of Claim 20, wherein the processing circuitry (82) is further configured to map a remaining set of blind decodings to CCEs of the given CCE aggregation level.

22. The WD (22) of any of Claims 13-21, wherein a location of control resource sets, CORESETs, are randomized.

23. The WD (22) of any of Claims 13-22, wherein the processing circuitry (82) is further configured to assume a random mapping of physical downlink control channels, PDCCHs, and to find corresponding CCE indices for CCEs in a CCE aggregation level.

24. The WD (22) of Claim 23, wherein finding corresponding indices for CCEs in a CCE aggregation level is performed for each of a plurality of CCE aggregation levels.

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