TECHNICAL FIELD

[0001] This description relates to wireless communications.

BACKGROUND

[0002] A communication system may be a facility that enables communication between two or more nodes or devices, such as fixed or mobile communication devices. Signals can be carried on wired or wireless carriers.

[0003] An example of a cellular communication system is an architecture that is being standardized by the 3 ^rd Generation Partnership Project (3GPP). A recent development in this field is often referred to as the long-term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio-access technology. E-UTRA (evolved UMTS Terrestrial Radio Access) is the air interface of 3GPP's Long Term Evolution (LTE) upgrade path for mobile networks. In LTE, base stations or access points (APs), which are referred to as enhanced Node AP (eNBs), provide wireless access within a coverage area or cell. In LTE, mobile devices, or mobile stations are referred to as user equipments (UE). LTE has included a number of improvements or developments. Aspects of LTE are also continuing to improve.

[0004] 5G New Radio (NR) development is part of a continued mobile broadband evolution process to meet the requirements of 5G, similar to earlier evolution of 3G and 4G wireless networks. 5G is also targeted at the new emerging use cases in addition to mobile broadband. A goal of 5G is to provide significant improvement in wireless performance, which may include new levels of data rate, latency, reliability, and security. 5GNR may also scale to efficiently connect the massive Internet of Things (loT) and may offer new types of mission-critical services. For example, ultra-reliable and low-latency communications (URLLC) devices may require high reliability and very low latency.

5G NR development can include 5G- Advanced which incorporates advances in multiple input - multiple output (MIMO) antennas, artificial intelligence, location positioning, dynamic spectrum sharing (DSS), etc. SUMMARY

[0005] According to an example embodiment, a device, a system, a non-transitory computer-readable medium (having stored thereon computer executable program code which can be executed on a computer system), and/or a method can perform a process including determining, by a user equipment, whether a control channel candidate of a first radio-access technology overlaps with at least one resource element of a second radioaccess technology, determining, by the user equipment, whether or not to process the control channel candidate of the first radio-access technology based on a predetermined criterion associated with the control channel candidate, in response to the user equipment determining not to process the control channel candidate, disable monitoring of the control channel candidate by the user equipment, and in response to the user equipment determining to process the control channel candidate, processing the control channel candidate by the user equipment.

[0006] Implementations can include one or more of the following features and/or any combinations thereof. For example, the first radio-access technology can be a new radio (NR) radio-access technology, the second radio-access technology can be a Long-Term Evolution (LTE) radio-access technology, the control channel candidate of the first radio-access technology can be a radio Physical Downlink Control Channel (PDCCH) candidate, and the resource element of the second radio-access technology can be an LTE Cell-Specific Reference Signal (CRS). The determining of whether a control channel candidate of a first radio-access technology overlaps with at least one resource element of a second radio-access technology can include determining whether the PDCCH candidate for the UE on a serving cell overlaps with at least one of an overlap tag and a list of overlaps. The determining of whether the control channel candidate of a first radio-access technology overlaps a resource element of a second radio-access technology can be prior to configuring a list of overlaps. The predetermined criterion of the control channel candidate can be indicated based on an aggregation level of the control channel candidate being smaller than an overlap processing threshold. The overlap processing threshold can be varied with at least one of cell conditions and a configuration of a network device serving the associated cell. The predetermined criterion of the control channel candidate can be indicated based on an aggregation level of the control channel candidate being smaller than an overlap processing threshold prior to configuring a list of overlaps. [0007] For example, the method can further include determining that the user equipment is configured to process control channel candidate of the first radio-access technology overlapping with the resource element of the second radio-access technology. The determining of whether or not to process the control channel candidate of the first radio-access technology can be further based on a serving cell search space configuration. The determining of not to process the control channel candidate of the first radio-access technology can include at least one of each search space and each the control channel candidate of the first radio-access technology of the search space is configured individually. The determining of not to process the control channel candidate of the first radio-access technology can include each search space is configured the same. The determining of whether or not to process the control channel candidate of the first radio-access technology can be further based on an aggregation level of a search space, and the search space can be configured the same for a plurality of control channel candidates of the first radio-access technology at the aggregation level. The determining of whether or not to process the control channel candidate of the first radio-access technology can be further based on a power difference between the resource element candidate of the first radio-access technology and the overlapping resource element of the second radio-access technology. The determining of whether or not to process the control channel candidate of the first radio-access technology can be further based on a derivation of allowed aggregation level at the user equipment and a network device serving the associated cell.

[0008] The details of one or more examples of embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a block diagram of a wireless network according to an example embodiment.

[0010] FIG. 2 illustrates a block diagram of a DSS resource grid according to an example embodiment.

[0011] FIG. 3 illustrates a block diagram of a method of operating a user equipment according to an example embodiment. [0012] FIG. 4 illustrates a block diagram of a method of operating a user equipment according to an example embodiment.

[0013] FIG. 5 is a block diagram of a wireless station or wireless node (e.g., AP, BS, gNB, RAN node, relay node, UE or user device, network node, network entity, DU, CU-CP, CU-CP, ... or other node) according to an example embodiment.

DETAILED DESCRIPTION

[0014] FIG. 1 is a block diagram of a wireless network 130 according to an example embodiment. In the wireless network 130 of FIG. 1, user devices 131, 132, 133 and 135, which may also be referred to as mobile stations (MSs) or user equipment (UEs), may be connected (and in communication) with a base station (BS) 134, 136 which may also be referred to as an access point (AP), an enhanced Node B (eNB), a BS, next generation Node B (gNB), a next generation enhanced Node B (ng-eNB), or a network node. The terms user device and user equipment (UE) may be used interchangeably. A BS may also include or may be referred to as a RAN (radio-access network) node, and may include a portion of a BS or a portion of a RAN node, such as (e.g., such as a centralized unit (CU) and/or a distributed unit (DU) in the case of a split BS). At least part of the functionalities of a BS (e.g., access point (AP), base station (BS) or (e)Node B (eNB), BS, RAN node) may also be carried out by any node, server or host which may be operably coupled to a transceiver, such as a remote radio head. BS (or AP) 134, 136 provides wireless coverage within a cell 138, including to user devices (or UEs) 131, 132, 133 and 135. Although only four user devices (or UEs) are shown as being connected or attached to BS 134, 136, any number of user devices may be provided. BS 134, 136 is also connected to a core network 150 via a SI interface or NG interface 151, 152. This is merely one simple example of a wireless network, and others may be used.

[0015] A base station (e.g., such as BS 134, 136) is an example of a radio-access network (RAN) node within a wireless network. A BS (or a RAN node) may be or may include (or may alternatively be referred to as), e.g., an access point (AP), a gNB, an eNB, or portion thereof (such as a centralized unit (CU) and/or a distributed unit (DU) in the case of a split BS or split gNB), or other network node. For example, a BS (or gNB) may include: a distributed unit (DU) network entity, such as a gNB-distributed unit (gNB-DU), and a centralized unit (CU) that may control multiple DUs. In some cases, for example, the centralized unit (CU) may be split or divided into: a control plane entity, such as a gNB- centralized (or central) unit-control plane (gNB-CU-CP), and a user plane entity, such as a gNB-centralized (or central) unit-user plane (gNB-CU-UP). For example, the CU subentities (gNB-CU-CP, gNB-CU-UP) may be provided as different logical entities or different software entities (e.g., as separate or distinct software entities, which communicate), which may be running or provided on the same hardware or server, in the cloud, etc., or may be provided on different hardware, systems or servers, e.g., physically separated or running on different systems, hardware or servers.

[0016] As noted, in a split configuration of a gNB/BS, the gNB functionality may be split into a DU and a CU. A distributed unit (DU) may provide or establish wireless communications with one or more UEs. Thus, a DUs may provide one or more cells, and may allow UEs to communicate with and/or establish a connection to the DU in order to receive wireless services, such as allowing the UE to send or receive data. A centralized (or central) unit (CU) may provide control functions and/or data-plane functions for one or more connected DUs, e.g., including control functions such as gNB control of transfer of user data, mobility control, radio-access network sharing, positioning, session management etc., except those functions allocated exclusively to the DU. CU may control the operation of DUs (e.g., a CU communicates with one or more DUs) over a front-haul (Fs) interface.

[0017] According to an illustrative example, in general, a BS node (e.g., BS, eNB, gNB, CU/DU, ... ) or a radio-access network (RAN) may be part of a mobile telecommunication system. A RAN (radio-access network) may include one or more BSs or RAN nodes that implement a radio-access technology, e.g., to allow one or more UEs to have access to a network or core network. Thus, for example, the RAN (RAN nodes, such as BSs or gNBs) may reside between one or more user devices or UEs and a core network. According to an example embodiment, each RAN node (e.g., BS, eNB, gNB, CU/DU, ... ) or BS may provide one or more wireless communication services for one or more UEs or user devices, e.g., to allow the UEs to have wireless access to a network, via the RAN node. Each RAN node or BS may perform or provide wireless communication services, e.g., such as allowing UEs or user devices to establish a wireless connection to the RAN node, and sending data to and/or receiving data from one or more of the UEs. For example, after establishing a connection to a UE, a RAN node (e.g., BS, eNB, gNB, CU/DU, ... ) may forward data to the UE that is received from a network or the core network, and/or forward data received from the UE to the network or core network. RAN nodes (e.g., BS, eNB, gNB, CU/DU, ... ) may perform a wide variety of other wireless functions or services, e.g., such as broadcasting control information (e.g., such as system information) to UEs, paging UEs when there is data to be delivered to the UE, assisting in handover of a UE between cells, scheduling of resources for uplink data transmission from the UE(s) and downlink data transmission to UE(s), sending control information to configure one or more UEs, and the like. These are a few examples of one or more functions that a RAN node or BS may perform. A base station may also be DU (Distributed Unit) part of IAB (Integrated Access and Backhaul) node (a.k.a. a relay node). DU facilitates the access link connection(s) for an IAB node.

[0018] A user device (user terminal, user equipment (UE), mobile terminal, handheld wireless device, etc.) may refer to a portable computing device that includes wireless mobile communication devices operating either with or without a subscriber identification module (SIM) (which may be referred to as Universal SIM), including, but not limited to, the following types of devices: a mobile station (MS), a mobile phone, a cell phone, a smartphone, a personal digital assistant (PDA), a handset, a device using a wireless modem (alarm or measurement device, etc.), a laptop and/or touch screen computer, a tablet, a phablet, a game console, a notebook, a vehicle, a sensor, and a multimedia device, as examples, or any other wireless device. It should be appreciated that a user device may also be (or may include) a nearly exclusive uplink only device, of which an example is a camera or video camera loading images or video clips to a network. A user device may be also MT (Mobile Termination) part of IAB (Integrated Access and Backhaul) node (a.k.a. a relay node). MT facilitates the backhaul connection for an IAB node.

[0019] In LTE (as an illustrative example), core network 150 may be referred to as Evolved Packet Core (EPC), which may include a mobility management entity (MME) which may handle or assist with mobility /handover of user devices between BSs, one or more gateways that may forward data and control signals between the BSs and packet data networks or the Internet, and other control functions or blocks. Other types of wireless networks, such as 5G (which may be referred to as New Radio (NR)) may also include a core network (e.g., which may be referred to as 5GC in 5G/NR).

[0020] In addition, by way of illustrative example, the various example embodiments or techniques described herein may be applied to various types of user devices or data service types, or may apply to user devices that may have multiple applications running thereon that may be of different data service types. New Radio (5G) development may support a number of different applications or a number of different data service types, such as for example: machine type communications (MTC), enhanced machine type communication (eMTC), massive MTC (mMTC), Internet of Things (loT), and/or narrowband loT user devices, enhanced mobile broadband (eMBB), and ultra-reliable and low-latency communications (URLLC). Many of these new 5G (NR) - related applications may require generally higher performance than previous wireless networks.

[0021] loT may refer to an ever-growing group of objects that may have Internet or network connectivity, so that these objects may send information to and receive information from other network devices. For example, many sensor type applications or devices may monitor a physical condition or a status and may send a report to a server or other network device, e.g., when an event occurs. Machine Type Communications (MTC, or Machine to Machine communications) may, for example, be characterized by fully automatic data generation, exchange, processing and actuation among intelligent machines, with or without intervention of humans. Enhanced mobile broadband (eMBB) may support much higher data rates than currently available in LTE.

[0022] Ultra-reliable and low-latency communications (URLLC) is a new data service type, or new usage scenario, which may be supported for New Radio (5G) systems. This enables emerging new applications and services, such as industrial automations, autonomous driving, vehicular safety, e-health services, and so on. 3 GPP targets in providing connectivity with reliability corresponding to block error rate (BLER) of 10-5 and up to 1 ms U-Plane (user/data plane) latency, by way of illustrative example. Thus, for example, URLLC user devices/UEs may require a significantly lower block error rate than other types of user devices/UEs as well as low latency (with or without requirement for simultaneous high reliability). Thus, for example, a URLLC UE (or URLLC application on a UE) may require much shorter latency, as compared to an eMBB UE (or an eMBB application running on a UE).

[0023] The various example embodiments may be applied to a wide variety of wireless technologies or wireless networks, such as LTE, LTE-A, 5G (New Radio (NR)), cmWave, and/or mmWave band networks, loT, MTC, eMTC, mMTC, eMBB, URLLC, etc., or any other wireless network or wireless technology. These example networks, technologies or data service types are provided only as illustrative examples.

[0024] Example implementations can be directed to a dynamic spectrum sharing (DSS) feature associated with a UE operating in a serving cell. Spectrum sharing can imply that multiple radio-access technology can share the same spectrum. For example, referring to FIG. 1, BS 134 can be associated with a first radio-access technology and BS 136 can be associated with a second radio-access technology. Alternatively, BS 134 and/or BS 136 can be associated with two radio-access technologies. For example, two radio-access technologies sharing the same spectrum can be LTE (e.g., 4G) and NR (e.g., 5G). Dynamic can indicate that channel allocation may not be static. Instead, channel allocation can vary in time and/or frequency (e.g., from subframe/slot to another). DSS can be an important feature as new radio-access technologies are implemented and/or deployed. For example, when deploying 4G-5G Dynamic Spectrum Sharing (DSS) one of the underlying principles was to minimize the impact to the legacy LTE network. This led to DSS deployments in low bands where NR had very limited PDCCH resources.

Example implementations can enable a UE to support, and be configured with, two overlapping CRS rate matching patterns.

[0025] In an example implementation, if a DSS feature (e.g., reception of NR PDCCH candidates that overlap with LTE CRS REs) is supported, the DSS feature can be supported by the UE performing channel estimation with a regular legacy DMRS pattern in frequency dimension (e.g., no change to UE assumption on PDCCH DMRS RE positions/pattern in a symbol that are used for the purpose of channel estimation). In an example implementation, reception of NR PDCCH candidates that overlap with LTE CRS REs can be supported by (e.g., Rell8) UEs assuming PDCCH and PDCCH-DMRS RE mapping are based on an earlier release (e.g., Rell5) from the UE side. A legacy channel estimation assumption can be used for using the PDCCH-DMRS for the channel estimation. Channel estimation on clean symbol(s) only, i.e., a PDCCH of more than 1 symbol duration (more than 1 symbol Control Resource SET) and with at least one “clean” symbol not overlapping with LTE CRS REs (this channel estimation option does not apply for 1 symbol CORESET), can be used for PDCCH-DMRS channel estimation.

[0026] FIG. 2 illustrates a block diagram of a DSS resource grid according to an example embodiment. The DSS resource grid 205 can include a plurality of blocks (not including the first column or the first row) representing resource elements (RE). In order to demodulate different downlink physical channels, in LTE a UE may require several channel estimates spread out on subcarriers and symbols. Therefore, LTE cell-specific reference symbols (LTE-CRS) can be inserted into the DSS resource grid 205. The LTE- CRS can be mapped to REs in the DSS resource grid 205. Blocks of the plurality of blocks the DSS resource grid 205 can include numbers (e.g., 0, 1, 2, 3) corresponding to the LTE-CRS associated with an antenna port (e.g., antenna ports 0-3). As an example, block 210 includes the number 1 indicating that block 210 corresponding to the LTE-CRS associated with antenna port 1.

[0027] As mentioned above, the DSS feature associated with a UE operating in a serving cell includes spectrum sharing implying that that multiple radio-access technology can share the same spectrum. For example, two radio-access technologies sharing the same spectrum can be LTE (e.g., 4G) and NR (e.g., 5G). The DSS resource grid 205 includes a column 215 of blocks including RE’s that each can be control channel candidates of a first radio-access technology (e.g., NR or 5G). In an example implementation, all blocks of the DSS resource grid 205 REs of a second radio-access technology (e.g., LTE or 4G). For example, as discussed above, LTE-CRS can be mapped to REs (e.g., block 210) in the DSS resource grid 205 if the second radio-access technology is LTE.

[0028] In an example implementation, a control channel candidate (e.g., each block of the column 215 of blocks) of the first radio-access technology can overlap with at least one resource element (e.g., any block of the DSS resource grid 205) of the second radioaccess technology. For example, blocks 220 of the DSS resource grid 205 can be resource elements of the second radio-access technology. For example, blocks 220 of the DSS resource grid 205 can be associated with an LTE-CRS and column 215 of blocks can be radio Physical Downlink Control Channel (PDCCH) candidate(s). Therefore, blocks 220 of the DSS resource grid 205 can be control channel candidates of the first radio-access technology that overlap with at least one resource element of the second radio-access technology. For example, blocks 220 of the DSS resource grid 205 can be PDCCH candidate(s) that overlap with LTE-CRS resource elements. PDCCH candidate(s) that overlap with LTE-CRS are sometimes called NR PDCCH collisions with LTE-CRS.

[0029] For PDCCH monitoring, NR uses a similar PDCCH blind decoding principle as LTE, i.e., UE performs a cyclic redundancy check (CRC), where the CRC bits can be masked with an identifier (RNTI) known by the user. The UE can be configured with multiple PDCCH candidates for each monitoring occassion, where the UE attempts to find one or more PDCCHs with predefined RNTIs. The UE attempts to decode each PDCCH candidate of the monitoring occasion and determines based on the RNTI-masked CRC check if there actually was a PDCCH on transmitted to it on a particular PDCCH candidate.

[0030] PDCCH candidates can be transmitted via resources defined by a CORESET (Control resource set). In the time-domain, a CORESET is configured with duration of 1, 2 or 3 OFDM symbols. A CORESET can be divided into resource element groups (REGs), each REG can include 12 subcarriers in frequency and 1 OFDM symbol in time. Each REG carrying PDCCH can carry its own DMRS, where 3 out of 12 subcarriers of the REG carry the PDCCH DMRS.

[0031] A PDCCH candidate can include a number L of Control Channel Elements (CCEs), each CCE containing 6 REGs. The number L is called the aggregation level (AL), L 6 {1, 2, 4, 8, 16}. The AL used for transmission of a downlink control DCI can be selected by the gNB based on channel quality to ensure the required reliability of the DCI.

[0032] A CCE can include one or more REG bundles, which are sets of adjacent REGs in frequency and time having common precoding. Two options for CCE-to-REG construction can be supported. For example, a first option can be interleaved CCE-to-REG mapping and a second option can be non-interleaved CCE-to-REG mapping.

[0033] The goal of interleaved mapping is to achieve frequency diversity within a CCE. With non-interleaved mapping, REG bundle size six was chosen for good channel estimation performance. The REG bundle size can be configured separately for each CORESET. [0034] Depending on the level of overlap of the NR PDCCH candidate with the LTE-CRS some PDCCH candidates (e.g., some aggregation levels) may not be useful, or prioritizing LTE-CRS over PDCCH, PDCCH over LTE-CRS or superimpose the two on the same RE maybe beneficial. The NR UE PDCCH receiver implementation can play a role in what transmission on the colliding REs (CRS, PDCCH or both superimposed) makes the best sense.

[0035] The PDCCH Search Space configuration can provide 0, 1, 2, 3, 4, 5, 6 or 8 PDCCH candidates for the UE to monitor per each aggregation level (1, 2, 4, 8, 16). Further, there may be a total number of PDCCH candidates the UE is equipped to process setting an upper limit to the total number of PDCCH candidates that can be configured for a Search Space. This upper limit is sometimes called the UE’s PDCCH Blind Decoding (BD) budget. The monitoringSlotPeriodictyAndOffset can indicate the time locations when the PDCCH candidates are to be monitored. This can be illustrated in Code Sample 1.

SearchSpace ::= SEQUENCE { searchSpaceld SearchSpaceld, controlResourceSetld ControlResourceSetld OPTIONAL, - Cond

SetupOnly monitoringSlotPeriodicityAndOffset CHOICE {

OPTIONAL, - Cond Setup duration INTEGER (2..2559) OPTIONAL, - Need R monitoringSymbolsWithinSlot BIT STRING (SIZE (14)) OPTIONAL, — Cond Setup nrofCandidates SEQUENCE { aggregationLevel 1 ENUMERATED {n0, nl, n2, n3, n4, n5, n6, n8}, aggregationLeve!2 ENUMERATED {n0, nl, n2, n3, n4, n5, n6, n8}, aggregationLeve!4 ENUMERATED {n0, nl, n2, n3, n4, n5, n6, n8}, aggregationLevel 8 ENUMERATED {n0, nl, n2, n3, n4, n5, n6, n8}, aggregationLevel 16 ENUMERATED {n0, nl, n2, n3, n4, n5, n6, n8}

Code Sample 1 [0036] The nrofCandidates can represent a number of PDCCH candidates per aggregation level. The number of candidates and aggregation levels can apply to all control channel formats unless a particular value is specified or a format-specific value is provided (see inside searchSpaceType). If configured in the SearchSpace of a cross carrier scheduled cell, this field can indicate the number of candidates and aggregation levels to be used on the linked scheduling cell.

[0037] As discussed above, the UE can be configured to process a PDCCH candidate (e.g., monitor a PDCCH candidate) that overlaps with LTE CRS REs. However, the gNB does not signal to the UE information regarding what will be transmitted on the resource elements where the PDCCH/PDCCH-DMRS and the LTE CRS collide. A problem can be that with some configurations and with some receiver types, certain aggregation level PDCCH candidates cannot be received correctly by the UE no matter how good the received signal conditions the UE experiences. The Search Space configuration may lead to the PDCCH candidates sometimes overlapping with the LTE CRS symbols and in some other times not overlapping with the LTE CRS symbols. A problem can be that these known-to-be-undecodable PDCCH candidates unnecessarily consume PDCCH blind decoding budget of the UE’s PDCCH receiver if those are assumed to be processed. Furthermore, a useless PDCCH blind decoding may increase the false positive probability as any processed PDCCH has a small probability to be mistakenly understood as a valid PDCCH when none was transmitted (where CRC check is found positive even if the gNB did not transmit the corresponding PDCCH at all). False positives may cause, for example, unwanted transmissions or reception attempts at the UE. It makes sense to minimize those events by the system design.

[0038] Example implementations can solve these and other problems using a UE configured to process an NR PDCCH that overlaps with the LTE CRS by determining whether or not a particular PDCCH candidate is processed (e.g., monitored) based on the configuration and the overlap with the LTE CRS. An advantage of the disclosed (and similar) example implementations can be that, based on the procedure, the UE can be configured to skip the PDCCH candidates that do not meet a predetermined criterion. This will reduce the UEs PDCCH monitoring burden and minimize the amount of false positive detection. [0039] FIG. 3 illustrates a block diagram of a method of operating a user equipment according to an example embodiment. In an example implementation, the UE can include hardware and/or software configured to enable processing of an NR PDCCH that overlaps (e.g., see the discussion above) with the LTE CRS. The UE can be configured to determine whether or not a particular PDCCH candidate is processed (monitored) or not based on the configuration and the overlap with the LTE CRS. The example implementation of FIG.3 may relate to one monitoring occasion and one search space. In alternative (or in addition) implementation, FIG. 3 can relate to one monitoring occasion and the associated search spaces. In the implementation described with regard to FIG. 3 the UE may follow a serial order for processing all the configured PDCCH candidates for the given monitoring occasion. However, in an alternative, or additional, implementation parallel processing may be applied.

[0040] As shown in FIG. 3, in step S305 a NR PDCCH configuration and LTE CRS pattern configuration is received. For example, the NR PDCCH configuration can be received (e.g., signalled) from a network device configured to serve the cell using a first radio-access technology (e.g., NR or 5G). For example, the LTE CRS pattern configuration can be received (e.g., signalled) from a network device configured to serve the cell using a second radio-access technology (e.g., LTE or 4G). For example, the NR PDCCH configuration and the LTE CRS pattern configuration can be received (e.g., signalled) from a network device configured to serve the cell using two radio-access technologies.

[0041] In step S310 a next PDCCH candidate is selected. In an example implementation, one PDCCH candidate can be selected (e.g., to be blindly decoded). The PDCCH candidate can have a predefined aggregation level and covers predefined CCEs. For example, referring to FIG. 2, each block of the column 215 of blocks of the DSS resource grid 205 can represent a PDCCH candidate. The blocks of the column 215 of blocks can be a subset of PDCCH candidates. In other words, other columns of blocks of the DSS resource grid 205 can represent PDCCH candidates. The subset of PDCCH candidates can be selected sequentially (referring to FIG. 2, 11-0 or 0-11). Therefore, the next PDCCH candidate can be the next sequential candidate of the subset of PDCCH candidates. [0042] In step S315 whether or not the PDCCH candidate overlaps with an LTE CRS is determined. In response to determining the PDCCH candidate overlaps with an LTE CRS, processing continues to step S325. In response to determining the PDCCH candidate does not overlap with an LTE CRS, processing continues to step S330. For example, if at least one RE of a PDCCH candidate for a UE on the serving cell overlaps with at least one RE of an LTE-CRS (e.g., identified with an overlap tag like LTE-CRS- ToMatchAround), or any of RE on a list of overlaps in LTE -RS (e.g., the LTE-CRS- PatternLists), the PDCCH candidate is considered as overlapping with LTE CRS. The determination can be done separately for each PDCCH monitoring occasion.

[0043] In step S320 whether or not the PDCCH candidate is to be processed is determined. In response to determining the PDCCH candidate is to be processed, processing continues to step S325. In response to determining the PDCCH candidate is not to be processed, processing continues to step S330. For example, whether or not the PDCCH candidate is to be processed based on a predetermined criterion associated with the PDCCH candidate. The predetermined criterion can be, for example, the aggregation level of the PDCCH candidate, a signal quality, the configured power level difference between the LTE-CRS and PDCCH symbols or resource elements, and/or the level of overlap with LTE CRS resource elements. The predetermined criterion can be a combination of two or more criteria.

[0044] For example, the determination of whether or not to process the overlapping PDCCH candidate can be based on search space (SS) configuration. The search space configuration can be based on a DSS resource grid (e.g., DSS resource grid 205). Criterion used in the determination of whether or not to process the overlapping PDCCH candidate can be configured individually for each Search Space and/or for each PDCCH candidate of the Search Space. In an example embodiment, the configuration can be common for all Search Spaces. In an example embodiment, the PDCCH processing criterion can be configured individually for each aggregation level (AL) of the Search Space (e.g., common for all PDCCH candidates of that aggregation level). For example, the criterion can be an AL threshold. For example, all PDCCH candidates of AL>n (or >n) are to be processed. Alternatively, all candidates of AL<n (or <n) are not to be processed. [0045] In an example implementation, a different configuration/threshold

(e.g., predetermined criterion) may be used for different levels of overlap. For example, for a set of multi-symbol PDCCH candidates (all PDCCH candidates in one SS have the same number of symbols) with 1 -symbol overlap there is a different threshold than when there is a 2-symbol overlap. The overlap threshold can be in frequency (e.g., N PRBs or N Control Channel Elements (CCEs) of a PDCCH candidate overlap with the LTE CRS REs). The overlap threshold in frequency can be applicable if the NR carrier is wider than the underlying LTE carrier and the LTE CRS symbol may overlap the PDCCH in frequency only partially.

[0046] Additionally, or alternatively, the PDCCH processing condition

(e.g., predetermined criterion) can be based on the predefined power difference between the superimposed (NR) PDCCH and LTE CRS. For example, certain PDCCH candidate with certain AL may be dropped (not processed) if the PDCCH power with respect to the LTE CRS power is below certain threshold (e.g., 3 dB).

[0047] In an example embodiment the determining of whether or not the PDCCH candidate is to be processed can be based on an implicit derivation of allowed AL at the UE and gNB. For example, if derived implicitly by the UE, the implicit derivation can be based on the AL used in the Common Search Space (CSS). The implicit derivation can be decoded during the RRC connection setup procedure. In this case, the gNB may be aware of which PDCCH AL UE decoded correctly (PDSCH HARQ feedback received for DL grants and UL transmission received for PUSCH grants) and establish a minimum set of AL for robustly scheduling the UE in a SS which overlaps with LTE CRS. A possible RRC can be illustrated in Code sample 2. nrofCandidates SEQUENCE { aggregationLevel 1 ENUMERATED {n0, nl, n2, n3, n4, n5, n6, n8}, aggregationLevel2 ENUMERATED {n0, nl, n2, n3, n4, n5, n6, n8}, aggregationLevel4 ENUMERATED {n0, nl, n2, n3, n4, n5, n6, n8}, aggregationLevel 8 ENUMERATED {n0, nl, n2, n3, n4, n5, n6, n8}, aggregationLevel 16 ENUMERATED {n0, nl, n2, n3, n4, n5, n6, n8}

} crsOverlapProcessingTreshold ENUMERATED n2, n4, n8, n 161

Code Sample 2 [0048] The crsOverlapProcessing Threshold (the name of this information element is exemplary) can be an aggregation level threshold for monitoring a PDCCH candidate when the candidate overlaps with LTE CRS. In addition, if at least one RE of a PDCCH candidate for a UE on the serving cell overlaps with at least one RE of Ite-CRS- ToMatch Around, or of LTE-CRS-PatternList, and the UE does not support the overlapping technique the UE is not required to monitor the PDCCH candidate.

[0049] In an example implementation, for the implicit derivation of AL which the UE can support for reliable scheduling. For example, an NR UE in idle mode is unaware of the CRS RM patterns used by an LTE cell of a DSS cell. The NR UE is aware that it is dealing with a NR DSS Cell only after entering connected mode and when its capabilities are known. At this stage the gNB would configure the UE with LTE CRS RM patterns. To arrive at this stage the UE would have had to decode several PDCCH allocation on the CSS. If the UE has been capable of decoding these with the presence of LTE CRS which it was unaware of, the UE can proceed to at least decode these ALs. Typically, a single AL is statically configured to be used until UE feedback (e.g., CSI reports) is available to perform PDCCH link adaptation. Therefore, the gNB can infer at least some ALs the UE would be able to appropriately decode with the presence of LTE CRS once the UE has transitioned successfully to connected mode.

[0050] In step S325 the PDCCH candidate is processed. For example, the UE can attempt to decode the PDCCH candidate to obtain the Downlink Control Information (DCI) if one was actually transmitted to the UE using this PDCCH candidate (the blind decoding of PDCCH candidates can be a process where the UE goes through all the configured PDCCH candidates and tries to decode them, in order to determine if any of the PDCCH candidates was used to transmit a PDCCH). In step S330 the PDCCH candidate is not processed. For example, the UE can skip the processing of the PDCCH candidate and/or disable monitoring of the PDCCH candidate.

[0051] In step S335 whether or not monitoring is complete is determined. In response to determining monitoring is complete, processing ends, and/or monitoring is complete. In response to determining monitoring is not complete, processing returns to step S310. For example, referring to FIG. 3, if all the PDCCH candidates configured for the search space in step S310 have been determined to be either processed (and subsequently also processed), or to be not processed, the monitoring is complete. Otherwise, monitoring may not be complete.

[0052] Example 1. FIG. 4 is a block diagram of a method of operating a user equipment according to an example embodiment. As shown in FIG. 4, in step S405 whether a control channel candidate of a first radio-access technology overlaps with at least one resource element of a second radio-access technology is determined by a user equipment. In step S410 whether or not to process the control channel candidate of the first radio-access technology is determined by the user equipment based on a predetermined criterion associated with the control channel candidate. In step S415 in response to the user equipment determining not to process the control channel candidate, monitoring of the control channel candidate is disabled by the user equipment. In step S420 in response to the user equipment determining to process the control channel candidate, the control channel candidate is processed by the user equipment.

[0053] Example 2. The method of Example 1, wherein the first radio-access technology can be a new radio (NR) radio-access technology, the second radio-access technology can be a Long-Term Evolution (LTE) radio-access technology, the control channel candidate of the first radio-access technology can be a radio Physical Downlink Control Channel (PDCCH) candidate, and the resource element of the second radio-access technology can be an LTE Cell-Specific Reference Signal (CRS).

[0054] Example 3. The method of Example 1, wherein the determining of whether a control channel candidate of a first radio-access technology overlaps with at least one resource element of a second radio-access technology can include determining whether the PDCCH candidate for the UE on a serving cell overlaps with at least one of an overlap tag and a list of overlaps.

[0055] Example 4. The method of Example 1, wherein the determining of whether the control channel candidate of a first radio-access technology overlaps a resource element of a second radio-access technology can be prior to configuring a list of overlaps.

[0056] Example 5. The method of Example 1, wherein the predetermined criterion of the control channel candidate can be indicated based on an aggregation level of the control channel candidate being smaller than an overlap processing threshold. [0057] Example 6. The method of Example 5, wherein the overlap processing threshold can be varied with at least one of cell conditions and a configuration of a network device serving the associated cell.

[0058] Example 7. The method of Example 1, wherein the predetermined criterion of the control channel candidate can be indicated based on an aggregation level of the control channel candidate being smaller than an overlap processing threshold prior to configuring a list of overlaps.

[0059] Example 8. The method of Example 1 can further include determining that the user equipment is configured to process control channel candidate of the first radioaccess technology overlapping with the resource element of the second radio-access technology.

[0060] Example 9. The method of Example 1, wherein the determining of whether or not to process the control channel candidate of the first radio-access technology can be further based on a serving cell search space configuration.

[0061] Example 10. The method of Example 9, wherein the determining of not to process the control channel candidate of the first radio-access technology can include at least one of each search space and each the control channel candidate of the first radioaccess technology of the search space is configured individually.

[0062] Example 11. The method of Example 9, wherein the determining of not to process the control channel candidate of the first radio-access technology can include each search space is configured the same.

[0063] Example 12. The method of Example 1, wherein the determining of whether or not to process the control channel candidate of the first radio-access technology can be further based on an aggregation level of a search space, and the search space can be configured the same for a plurality of control channel candidates of the first radio-access technology at the aggregation level.

[0064] Example 13. The method of Example 1 , wherein the determining of whether or not to process the control channel candidate of the first radio-access technology can be further based on a power difference between the resource element candidate of the first radio-access technology and the overlapping resource element of the second radio-access technology. [0065] Example 14. The method of Example 1, wherein the determining of whether or not to process the control channel candidate of the first radio-access technology can be further based on a derivation of allowed aggregation level at the user equipment and a network device serving the associated cell.

[0066] Example 15. A non-transitory computer-readable storage medium comprising instructions stored thereon that, when executed by at least one processor, are configured to cause a computing system to perform the method of any of Examples 1-14.

[0067] Example 16. An apparatus comprising means for performing the method of any of Examples 1-14.

[0068] Example 17. An apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform the method of any of Examples 1-14.

[0069] FIG. 5 is a block diagram of a wireless station 500 or wireless node or network node 500 according to an example embodiment. The wireless node or wireless station or network node 500 may include, e.g., one or more of an AP, BS, gNB, RAN node, relay node, UE or user device, network node, network entity, DU, CU-CP, CU-UP, ... or other node according to an example embodiment.

[0070] The wireless station 500 may include, for example, one or more (e.g., two as shown in FIG. 5) radio frequency (RF) or wireless transceivers 502A, 502B, where each wireless transceiver includes a transmitter to transmit signals and a receiver to receive signals. The wireless station also includes a processor or control unit/entity (controller) 504 to execute instructions or software and control transmission and receptions of signals, and a memory 506 to store data and/or instructions.

[0071] Processor 504 may also make decisions or determinations, generate frames, packets or messages for transmission, decode received frames or messages for further processing, and other tasks or functions described herein. Processor 504, which may be a baseband processor, for example, may generate messages, packets, frames or other signals for transmission via wireless transceiver 502A and/or 502B. Processor 504 may control transmission of signals or messages over a wireless network, and may control the reception of signals or messages, etc., via a wireless network (e.g., after being down-converted by wireless transceiver 502A/502B, for example). Processor 504 may be programmable and capable of executing software or other instructions stored in memory or on other computer media to perform the various tasks and functions described above, such as one or more of the tasks or methods described above. Processor 504 may be (or may include), for example, hardware, programmable logic, a programmable processor that executes software or firmware, and/or any combination of these. Using other terminology, processor 504 and transceiver 502A/502B together may be considered as a wireless transmitter/receiver system, for example.

[0072] In addition, referring to FIG. 5, a controller (or processor) 508 may execute software and instructions, and may provide overall control for the station 500, and may provide control for other systems not shown in FIG. 5, such as controlling input/output devices (e.g., display, keypad), and/or may execute software for one or more applications that may be provided on wireless station 500, such as, for example, an email program, audio/video applications, a word processor, a Voice over IP application, or other application or software.

[0073] In addition, a storage medium may be provided that includes stored instructions, which when executed by a controller or processor may result in the processor 504, or other controller or processor, performing one or more of the functions or tasks described above.

[0074] According to another example embodiment, RF or wireless transceiver(s) 502A/502B may receive signals or data and/or transmit or send signals or data. Processor 504 (and possibly transceivers 502A/502B) may control the RF or wireless transceiver 502A or 502B to receive, send, broadcast or transmit signals or data.

[0075] The example embodiments are not, however, restricted to the system that is given as an example, but a person skilled in the art may apply the solution to other communication systems. Another example of a suitable communications system is the 5G system. It is assumed that network architecture in 5G will be quite similar to that of the LTE-advanced. 5G is likely to use multiple input - multiple output (MIMO) antennas, many more base stations or nodes than the LTE (a so-called small cell concept), including macro sites operating in co-operation with smaller stations and perhaps also employing a variety of radio technologies for better coverage and enhanced data rates. [0076] It should be appreciated that future networks will most probably utilize network functions virtualization (NFV) which is a network architecture concept that proposes virtualizing network node functions into “building blocks” or entities that may be operationally connected or linked together to provide services. A virtualized network function (VNF) may comprise one or more virtual machines running computer program codes using standard or general type servers instead of customized hardware. Cloud computing or data storage may also be utilized. In radio communications this may mean node operations may be carried out, at least partly, in a server, host or node operationally coupled to a remote radio head. It is also possible that node operations will be distributed among a plurality of servers, nodes or hosts. It should also be understood that the distribution of labor between core network operations and base station operations may differ from that of the LTE or even be non-existent.

[0077] Example embodiments of the various techniques described herein may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. Example embodiments may be implemented as a computer program product, i.e., a computer program tangibly embodied in an information carrier, e.g., in a machine-readable storage device or in a propagated signal, for execution by, or to control the operation of, a data processing apparatus, e.g., a programmable processor, a computer, or multiple computers. Embodiments may also be provided on a computer readable medium or computer readable storage medium, which may be a non-transitory medium. Embodiments of the various techniques may also include embodiments provided via transitory signals or media, and/or programs and/or software embodiments that are downloadable via the Internet or other network(s), either wired networks and/or wireless networks. In addition, embodiments may be provided via machine type communications (MTC), and also via an Internet of Things (IOT).

[0078] The computer program may be in source code form, object code form, or in some intermediate form, and it may be stored in some sort of carrier, distribution medium, or computer readable medium, which may be any entity or device capable of carrying the program. Such carriers include a record medium, computer memory, read-only memory, photoelectrical and/or electrical carrier signal, telecommunications signal, and software distribution package, for example. Depending on the processing power needed, the computer program may be executed in a single electronic digital computer, or it may be distributed amongst a number of computers.

[0079] Furthermore, example embodiments of the various techniques described herein may use a cyber-physical system (CPS) (a system of collaborating computational elements controlling physical entities). CPS may enable the embodiment and exploitation of massive amounts of interconnected ICT devices (sensors, actuators, processors microcontrollers, ...) embedded in physical objects at different locations. Mobile cyber physical systems, in which the physical system in question has inherent mobility, are a subcategory of cyber-physical systems. Examples of mobile physical systems include mobile robotics and electronics transported by humans or animals. The rise in popularity of smartphones has increased interest in the area of mobile cyber-physical systems. Therefore, various embodiments of techniques described herein may be provided via one or more of these technologies.

[0080] A computer program, such as the computer program(s) described above, can be written in any form of programming language, including compiled or interpreted languages, and can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit or part of it suitable for use in a computing environment. A computer program can be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network.

[0081] Method steps may be performed by one or more programmable processors executing a computer program or computer program portions to perform functions by operating on input data and generating output. Method steps also may be performed by, and an apparatus may be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit).

[0082] Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer, chip or chipset. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. Elements of a computer may include at least one processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer also may include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto-optical disks, or optical disks. Information carriers suitable for embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory may be supplemented by, or incorporated in, special purpose logic circuitry.

[0083] To provide for interaction with a user, embodiments may be implemented on a computer having a display device, e.g., a cathode ray tube (CRT) or liquid crystal display (LCD) monitor, for displaying information to the user and a user interface, such as a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input.

[0084] Example embodiments may be implemented in a computing system that includes a back-end component, e.g., as a data server, or that includes a middleware component, e.g., an application server, or that includes a front-end component, e.g., a client computer having a graphical user interface or a Web browser through which a user can interact with an embodiment, or any combination of such back-end, middleware, or front-end components. Components may be interconnected by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include a local area network (LAN) and a wide area network (WAN), e.g., the Internet.

[0085] While certain features of the described embodiments have been illustrated as described herein, many modifications, substitutions, changes and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the various embodiments.