Physical downlink control channel transmission and reception technology for dynamic spectrum sharing

Abstract

A user equipment (UE) is configured to perform rate matching of a reference signal under certain conditions. The UE receives information associated with a downlink reference signal for a first radio access technology (RAT), wherein the first RAT is different from a currently camped second RAT; identifies a reference signal opportunity for the downlink reference signal; and receives downlink control information from the second RAT via a physical downlink control channel (PDCCH).

Description

Technical Field

[0001] The present application relates generally to wireless communications, and more particularly to physical downlink control channel transmission and reception techniques for dynamic spectrum sharing. Background Art

[0002] Dynamic spectrum sharing may include deploying multiple radio access technologies (RATs) in the same frequency band and dynamically allocating spectrum resources between these RATs. When multiple RATs share the same frequency band, conflicts may occur between signals of different RATs. For example, Long Term Evolution (LTE) RATs and 5G New Radio (NR) RATs may be deployed in the same frequency band. In this type of scenario, 5G NR downlink control information (DCI) transmitted via the Physical Downlink Control Channel (PDCCH) may conflict with LTE downlink reference signals. This may result in performance degradation for both 5G NR and LTE operations. Therefore, there is a need for technology that is configured to ensure that 5G NR PDCCH signaling does not conflict with LTE downlink reference signals. Summary of the Invention

[0003] Some example embodiments relate to a baseband processor configured to perform operations including: receiving information associated with a downlink reference signal for a first radio access technology (RAT), wherein the first RAT is different from a currently camped-on second RAT; identifying a reference signal opportunity for the downlink reference signal; and receiving downlink control information from the second RAT via a physical downlink control channel (PDCCH).

[0004] Other exemplary embodiments relate to a user equipment (UE) comprising: a transceiver configured to communicate with a network; and a processor communicatively coupled to the transceiver and configured to perform operations. The operations include: receiving information associated with a downlink reference signal for a first radio access technology (RAT), wherein the first RAT is different from a currently camped second RAT; identifying a reference signal opportunity for the downlink reference signal; and receiving downlink control information from the second RAT via a physical downlink control channel (PDCCH). BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 Exemplary network arrangements are shown according to various exemplary embodiments.

[0006] Figure 2 An exemplary user equipment (UE) is shown in accordance with various exemplary embodiments.

[0007] Figure 3Methods for Physical Downlink Control Channel (PDCCH) reception according to various exemplary embodiments are shown.

[0008] Figure 4 Examples of exemplary PDCCH demodulation reference signal (DMRS) designs are shown in accordance with various exemplary embodiments.

[0009] Figure 5 Three examples of Long Term Evolution (LTE) cell-specific reference signal (CRS) transmission and one example of 5G New Radio (NR) PDCCH DMRS transmission are shown according to various exemplary embodiments. DETAILED DESCRIPTION

[0010] The exemplary embodiments may be further understood with reference to the following description and associated drawings, in which similar elements bear the same reference numerals. The exemplary embodiments relate to 5G New Radio (NR) physical downlink control channel (PDCCH) transmission and reception. As will be described in more detail below, in a first aspect, the exemplary embodiments include various exemplary rate matching techniques that can be implemented by a user equipment (UE) for PDCCH reception. In a second aspect, the exemplary embodiments include an exemplary PDCCH demodulation reference signal (DMRS) design.

[0011] The exemplary embodiments are described with respect to a UE. However, reference to a UE is provided for illustrative purposes only. The exemplary embodiments may be used with any electronic component that can establish a connection with a network and is configured with hardware, software, and / or firmware for exchanging information and data with the network. Therefore, UE as described herein is used to represent any electronic component.

[0012] Example embodiments are also described with respect to dynamic spectrum sharing (DSS) between Long Term Evolution (LTE) radio access technologies (RATs) and 5G NR RATs. Those skilled in the art will understand that DSS refers to deploying multiple RATs in the same frequency band and dynamically allocating spectrum resources between those RATs. DSS can enable network operators to deploy 5G NR on top of spectrum already used for LTE. However, when multiple RATs share the same frequency band, collisions may occur between signals from different RATs. This can result in performance degradation on the UE side and / or the network side for both LTE operation and 5G NR operation.

[0013] In accordance with various regulations and / or standards, the DSS can be configured to ensure that LTE operation is not affected by the presence of 5G NR communications in the same frequency band. This is to ensure backward compatibility with legacy LTE UEs. However, since 5G NR communications are invisible to LTE operations, the DSS can rely on the 5G NR operation to be configured to avoid conflicts with LTE communications. As will be described in more detail below, exemplary embodiments include techniques for avoiding conflicts between the 5G NR PDCCH and certain LTE downlink reference signals.

[0014] The exemplary embodiments are also described with respect to downlink control information (DCI). Those skilled in the art will understand that DCI may refer to control information that indicates that the UE will perform subsequent transmission and / or reception. To provide an example, the DCI may be transmitted to the UE by the currently occupied cell via the PDCCH. In one example, the DCI may include scheduling information for downlink data to be received via a downlink data channel (e.g., a physical downlink shared channel (PDSCH), etc.) or uplink data to be transmitted via an uplink data channel (physical uplink shared channel (PUSCH)). In another example, the DCI may include scheduling information for other control information to be received by the UE (e.g., a medium access control (MAC) control element (CE)) or scheduling information for other control information to be transmitted by the UE (e.g., a sounding reference signal (SRS)). Therefore, the UE may transmit and / or receive signals in response to the DCI. The above examples are provided for illustrative purposes and are not intended to limit the exemplary embodiments in any way, and those skilled in the art will understand the scope of the term "DCI".

[0015] As described above, the UE may receive DCI from the network via the PDCCH. For 5G NR UEs, PDCCH reception may include rate matching around the LTE cell-specific reference signal (CRS). In one aspect, exemplary embodiments relate to implementing 5G NR PDCCH rate matching techniques for DSS. Some of these exemplary techniques are configured to strike a balance between the complexity and resources required for the network to provide the PDCCH and the resources required for the UE to perform PDCCH reception. For example, some of the exemplary rate matching techniques described herein involve implementing restrictions on when or under what conditions rate matching LTE CRS is performed for PDCCH reception. These restrictions enable operators to meet DSS requirements without placing unreasonable demands on the UE or the network.

[0016] In a second aspect, exemplary embodiments include implementing a PDCCH DMRS design. This exemplary PDCCH DMRS design reduces the likelihood of collisions between the PDCCH DMRS and the LTE CRS. The exemplary PDCCH DMRS design described herein can be used in conjunction with or independently of the exemplary rate matching techniques described herein. Furthermore, the exemplary rate matching techniques and PDCCH DMRS design described herein can be used in conjunction with other currently implemented DSS mechanisms, future implementations of DSS mechanisms, or independently of other DSS mechanisms.

[0017] Figure 1 An exemplary network arrangement 100 according to various exemplary embodiments is shown. The exemplary network arrangement 100 includes a UE 110. Those skilled in the art will appreciate that the UE 110 can be any type of electronic component configured to communicate via a network, such as a mobile phone, tablet computer, desktop computer, smartphone, phablet, embedded device, wearable device, Internet of Things (IoT) device, etc. It should also be understood that an actual network arrangement can include any number of UEs used by any number of users. Therefore, for illustrative purposes, only an example with a single UE 110 is provided.

[0018] UE 110 can be configured to communicate with one or more networks. In the example of network configuration 100, the networks with which UE 110 can wirelessly communicate are 5G NR radio access network (RAN) 120, LTE RAN 122, and wireless local area network (WLAN) 124. However, it should be understood that UE 110 can also communicate with other types of networks (e.g., 5G cloud RAN, next generation RAN (NG-RAN), traditional cellular networks, etc.), and UE 110 can also communicate with the network through a wired connection. With respect to the exemplary embodiment, UE 110 can establish a connection with 5G NR RAN 120, LTE RAN 122, and / or WLAN 124. Thus, UE 110 can have a 5G NR chipset for communicating with NR RAN 120, an LTE chipset for communicating with LTE-RAN 122, and an ISM chipset for communicating with WLAN 124.

[0019] 5G NR RAN 120 and LTE-RAN 122 may be part of a cellular network that may be deployed by a network operator (e.g., Verizon, AT&T, T-Mobile, etc.). RANs 120 and 122 may include cells or base stations configured to send and receive traffic from UEs equipped with appropriate cellular chipsets. In this example, 5G NR RAN 120 includes gNB 120A, and LTE RAN 122 includes eNB 122A. However, reference to gNB and eNB is provided for illustration purposes only, and any suitable base station or cell (e.g., Node B, eNodeB, HeNB, eNB, gNB, gNodeB, macrocell, microcell, small cell, femtocell, etc.) may be deployed. WLAN 124 may include any type of wireless local area network (WiFi, hotspot, IEEE 802.11x network, etc.).

[0020] A base station (e.g., gNB 120A, eNB 122A) may include one or more communication interfaces to exchange data and / or information with a camped UE, a corresponding RAN, a cellular core network 130, the Internet 140, and the like. In addition, the base station may include a processor configured to perform various operations. For example, the processor of the base station may be configured to perform operations related to PDCCH transmission. However, reference to the processor is for illustrative purposes only. The operations of the base station may also be represented as independently incorporated components of the base station, or may be modular components coupled to the base station, such as an integrated circuit with or without firmware. For example, an integrated circuit may include input circuitry for receiving signals and processing circuitry for processing signals and other information. In addition, in some base stations, the functionality of the processor is shared between two or more processors, such as a baseband processor and an application processor. The exemplary embodiments may be implemented in accordance with any of these or other configurations of the base station.

[0021] Those skilled in the art will appreciate that any relevant procedures may be performed for UE 110 to connect to 5G NR RAN 120. For example, as described above, 5G NR RAN 120 may be associated with a specific network operator, where UE 110 and / or its user has protocol and credential information (e.g., stored on a SIM card). Upon detecting the presence of 5G NR RAN 120, UE 110 may transmit corresponding credential information in order to associate with 5G NR RAN 120. More specifically, UE 110 may associate with a specific cell (e.g., gNB 120A).

[0022] As described above, the exemplary embodiments relate to DSS. Therefore, reference to a single 5G NR RAN 120 and a single LTE RAN 122 is provided for illustrative purposes only. In some embodiments, a single RAN may be configured to deploy both LTE RAT and 5G NR RAT. In other embodiments, there may be multiple RANs deployed with overlapping coverage areas. Similarly, for illustrative purposes, reference to a single gNB 120A and a single eNB 122A is also provided. In some embodiments, a single base station or cell may be configured for both LTE RAT and 5G NR RAT. In other embodiments, multiple 5G NR base stations and multiple LTE base stations may be deployed with overlapping coverage areas. The exemplary embodiments are not limited to any particular arrangement of RANs and base stations. The exemplary embodiments may be applied to any network arrangement that includes DSS functionality.

[0023] In addition to RANs 120 and 122, network arrangement 100 includes a cellular core network 130, the Internet 140, an IP Multimedia Subsystem (IMS) 150, and a network services backbone 160. Cellular core network 130 can be considered an interconnected collection of components that manage the operation and traffic of a cellular network. Cellular core network 130 also manages traffic flowing between the cellular network and the Internet 140. IMS 150 can generally be described as an architecture for delivering multimedia services to UE 110 using IP protocols. IMS 150 can communicate with cellular core network 130 and the Internet 140 to provide multimedia services to UE 110. Network services backbone 160 communicates directly or indirectly with the Internet 140 and cellular core network 130. Network services backbone 160 can generally be described as a set of components (e.g., servers, network storage arrangements, etc.) that implement a suite of services that can be used to extend the functionality of UE 110 to communicate with various networks.

[0024] Figure 2 An exemplary UE 110 is shown according to various exemplary embodiments. Figure 1 10. The UE 110 may represent any electronic device and may include a processor 205, a memory arrangement 210, a display device 215, an input / output (I / O) device 220, a transceiver 225, and other components 230. The other components 230 may include, for example, an audio input device, an audio output device, a battery providing a limited power source, a data acquisition device, a port for electrically connecting the UE 110 to other electronic devices, sensors for detecting conditions of the UE 110, and the like.

[0025] The processor 205 may be configured to execute multiple engines of the UE 110. For example, the engines may include a 5G NR PDCCH rate matching engine 235. The 5G NR PDCCH rate matching engine 235 may be configured to implement various exemplary rate matching techniques related to 5G NR PDCCH reception.

[0026] The engine described above as an application (e.g., a program) executed by the processor 205 is merely exemplary. The functionality associated with the engine may also be represented as a separate, integrated component of the UE 110, or may be a modular component coupled to the UE 110, such as an integrated circuit with or without firmware. For example, an integrated circuit may include input circuitry for receiving signals and processing circuitry for processing signals and other information. The engine may also be embodied as one application or multiple independent applications. In addition, in some UEs, the functionality described for the processor 205 is shared between two or more processors, such as a baseband processor and an application processor. The exemplary embodiments may be implemented in any of these or other configurations of the UE.

[0027] The memory 210 may be a hardware component configured to store data related to operations performed by the UE 110. The display device 215 may be a hardware component configured to display data to a user, and the I / O device 220 may be a hardware component that enables user input. The display device 215 and the I / O device 220 may be separate components or may be integrated together (such as a touch screen). The transceiver 225 may be a hardware component configured to establish a connection with the 5G NR RAN 120, the LTE RAN 122, and the WLAN 124. Thus, the transceiver 225 may operate on a variety of different frequencies or channels (e.g., a set of continuous frequencies).

[0028] Figure 3 A method 300 for PDCCH reception according to various exemplary embodiments is shown. Figure 1 The network arrangement 100 and Figure 2 The method 300 is described with reference to the UE 110.

[0029] In 305, UE 110 camps on a cell of a first RAT. For example, UE 110 may camp on gNB 120A of 5G NR-RAN 120. As indicated above, the exemplary embodiments relate to DSS. Thus, 5G NR RAT and LTE RAT may be deployed in the same frequency band. For example, 5G NR PDCCH may be configured to use the same frequency band as LTE CRS. Additionally, while camped on a 5G NR cell, UE 110 may indicate to the network that UE 110 is capable of rate matching around LTE CRS during PDCCH reception. For example, UE 110 may transmit capability information (or any other appropriate message) to the network that indicates the rate matching capability of UE 110 on a per-band basis.

[0030] At 310, UE 110 may receive coexistence information for a second RAT that is different from the RAT of the currently camped cell. For example, UE 110 may be configured for a 5G NR RAT, and the coexistence information may be associated with an LTE RAT. The coexistence information may enable UE 110 to identify the frequency and / or time location of one or more types of LTE downlink reference signals that may be transmitted by the LTE cell (e.g., LTE CRS).

[0031] In this example, UE 110 may not need to detect the presence and pattern of LTE CRS to be transmitted on the currently occupied frequency band. Instead, coexistence information may be provided by the currently occupied 5G NR cell and explicitly or implicitly indicate the mode (or rate) to be used by the LTE cell to transmit LTE CRS. UE 110 may receive this coexistence information from the 5G NR cell or from any other appropriate source during radio resource control (RRC) signaling. Thus, a cell of a first RAT may provide coexistence information for a second, different RAT to the UE. However, exemplary embodiments are not limited to scenarios where coexistence information is explicitly or implicitly provided to UE 110 from the currently occupied cell. Exemplary embodiments may collect information associated with the mode (or rate) to be used by the cell to transmit LTE reference signals from any appropriate source or sources external or internal to UE 110.

[0032] In 315, UE 110 identifies a reference signal (e.g., LTE CRS) timing for the second RAT based on the coexistence information. In other words, UE 110 identifies the mode (or rate) at which LTE CRS will be transmitted in the frequency band of the currently camped 5G NR cell.

[0033] In 320, UE 110 performs rate matching around a reference signal for a second RAT during PDCCH reception for a first RAT. For example, UE 110 may receive control information via a 5G NR PDCCH. Since UE 110 knows the mode (or rate) being used to transmit LTE CRS in the frequency band of the currently camped 5G NR cell, UE 110 may perform rate matching around the LTE CRS during 5G NR PDCCH reception. Those skilled in the art will appreciate that, generally speaking, rate matching is a processing technique that includes demapping one or more symbols of a downlink signal and skipping the identified reference signal (e.g., LTE CRS) opportunities during the demapping operation.

[0034] UE 110 may configure the baseband processor to perform rate matching around the LTE CRS based on certain predetermined conditions. Thus, UE 110 may be configured to perform rate matching around the LTE CRS when a first set of one or more conditions are met, and may be restricted from performing rate matching around the LTE CRS when a second set of one or more conditions are met.

[0035] Specific examples of when and / or under what conditions UE 110 performs rate matching around LTE CRS are described in greater detail below. Some of the example rate matching techniques described below are configured to balance the complexity and resources required by the network to provide PDCCHs with the resources required by UE 110 to perform PDCCH reception. For example, implementing these limits can enable operators to meet DSS requirements without placing unreasonable demands on the UE or the network. During operation, any combination of one or more of the example rate matching techniques described herein may be implemented.

[0036] In one example, UE 110 may be configured to perform rate matching around LTE CRS when decoding a search space and / or control resource set (CORESET) configured after RRC connection establishment for 5G NR PDCCH reception. For example, during or after the RRC connection establishment process, UE 110 may be configured to receive 5G NR PDCCH in a specific search space or via a specific CORESET. In response, UE 110 may configure the baseband processor to perform rate matching around LTE CRS when receiving on the indicated search space or indicated CORESET because the baseband processor is configured after (or during) RRC connection establishment. However, when UE 110 is to receive PDCCH on a search space or via a CORESET configured before RRC connection setup or after the RRC connection has been terminated, UE 110 may restrict the baseband processor from performing rate matching around LTE CRS.

[0037] In another example, UE 110 may be configured to perform rate matching around LTE CRS when processing a UE-specific search space (USS) for 5G NR PDCCH reception. For example, when UE 110 will receive PDCCH on the USS, UE 110 may configure the baseband processor to perform rate matching around LTE CRS. In this example, when UE 110 will receive PDCCH on the common search space (CSS), UE 110 may restrict the baseband processor from performing rate matching around LTE CRS. Thus, UE 110 may implement rate matching around LTE CRS based on a first type of search space and omit rate matching around LTE CRS based on a second, different type of search space.

[0038] In another example, UE 110 may be configured to perform rate matching around LTE CRS for 5G NR PDCCH reception in licensed spectrum. For example, when UE 110 will receive PDCCH in licensed spectrum, UE 110 may configure the baseband processor to perform rate matching around LTE CRS. In this example, when UE 110 will receive PDCCH in unlicensed spectrum (e.g., NR-U, sidelink, etc.), UE 110 may restrict the baseband processor from performing rate matching around LTE CRS. Thus, UE 110 may implement rate matching around LTE CRS based on receiving PDCCH via licensed spectrum, and omit rate matching around LTE CRS based on receiving PDCCH via unlicensed spectrum.

[0039] In another example, UE 110 may be configured to perform rate matching around the LTE CRS for 5G NR PDCCH reception based on the type of DCI to be received. UE 110 may determine the type of DCI to be received based on information received from the network, as indicated in the DCI or in any other appropriate manner. In this example, UE 110 may configure the baseband processor to perform rate matching around the LTE CRS when non-fallback DCI (e.g., DCI format 0_1, format 0_2, format 1_1, format 1_2, etc.) is to be received via 5G NR PDCCH. UE 110 may also restrict the baseband processor from performing rate matching around the LTE CRS when fallback DCI (e.g., DCI format 0_0, format 1_0, etc.) or special DCI (e.g., DCI format 2_x, etc.) is to be received. Thus, UE 110 may perform rate matching around the LTE CRS based on the received PDCCH based on a first type of DCI and omit rate matching around the LTE CRS based on a second, different type of DCI.

[0040] In another example, UE 110 can be configured to perform rate matching around the LTE CRS based on a radio network temporary identifier (RNTI). Those skilled in the art will appreciate that a UE can be assigned a variety of different RNTIs for a variety of different services. During operation, the network can transmit a signal to the UE that includes DCI scrambled with one of the RNTIs. Thus, UE 110 can implement rate matching based on the RNTI used to scramble the DCI.

[0041] To provide an example, when DCI is scrambled using an RNTI from a first set of RNTIs, UE 110 may configure the baseband processor to perform rate matching around the LTE CRS. In this example, the first set includes the cell RNTI (C-RNTI), the configuration scheduling RNTI (CS-RNTI), and the modulation and coding scheme cell RNTI (MCS-C-RNTI). When DCI is scrambled using an RNTI from a second set of RNTIs, UE 110 may restrict the baseband processor from performing rate matching around the LTE CRS. In this example, the second group includes system information RNTI (SI-RNTI), paging RNTI (P-RNTI), random access RNTI (RA-RNTI), temporary C-RNTI, RNTI configured for MsgB reception (MsgB-RNTI), slot format indicator RNTI (SFI-RNTI), interruption RNTI (INT-RNTI), transmission power control physical uplink shared channel RNTI (TPC-PUSCH-RNTI), transmission power control physical uplink control channel RNTI (TPC-PUCCH-RNTI), and transmission power control sounding reference signal RNTI (TPC-SRS-RNTI). Therefore, UE 110 can perform rate matching around LTE CRS based on receiving PDCCH scrambled with RNTI from the first group of RNTIs, and omit rate matching around LTE CRS based on receiving PDCCH scrambled with RNTI from the second group of RNTIs. The above examples are provided for illustrative purposes only and are not intended to limit the exemplary embodiments in any way. The example embodiments may be applied to any number and type of RNTIs that are divided into first and second groups for any appropriate reasons.

[0042] In addition, exemplary embodiments include implementing control resource set (CORESET) restrictions related to rate matching around LTE CRS. As described above, implementing these restrictions can enable operators to meet DSS without placing unreasonable demands on UEs or networks.

[0043] In some embodiments, UE 110 may only support rate matching around LTE CRS for receiving a CORESET with a precoder granularity of "allContiguousRB". A CORESET configured with this parameter indicates that DMRS symbols on all RBs allocated to the CORESET are transmitted with the same precoder. In one example, the network may assume that no UE supports the precoder granularity of "sameAsREG-bundle". A CORESET configured with this parameter indicates that DMRS REs transmitted in the same REG bundle are transmitted with the same precoder. Therefore, based on this assumption, for a CORESET configured with a precoder granularity of sameAsREG-bundle, the network may not transmit and / or expect UE 110 to perform rate matching around LTE CRS.

[0044] In another example, UE 110 may report whether UE 110 supports rate matching around LTE CRS for receiving a CORESET configured with a precoder granularity parameter of sameAsREG-bundle. UE 110 may report this capability in a capability information message or in any other appropriate type of message. Thus, when UE 110 indicates that it does not support the corresponding capability, the network may not transmit and / or expect UE 110 to perform rate matching around LTE CRS for a CORESET configured with a precoder granularity of sameAsREG-bundle.

[0045] In some embodiments, additional restrictions may be placed on the REG bundle size of a CORESET. For example, UE 110 may configure the baseband processor to perform rate matching around the LTE CRS for a CORESET with a REG bundle size equal to (n6), and restrict the baseband processor from performing rate matching around the LTE CRS for a CORESET with a REG bundle size equal to (n2) or (n3). This restriction may be assumed by the network or indicated to the network by UE 110. Thus, for a CORESET configured with a particular REG bundle size, the network may not transmit and / or expect UE 110 to perform rate matching around the LTE CRS.

[0046] In other embodiments, additional restrictions may be imposed on the interleaving of CORESETs. For example, UE 110 may configure the baseband processor to perform rate matching around LTE CRS only for non-interleaved CORESETs. In another example, UE 110 may configure the baseband processor to perform rate matching around LTE CRS for CORESETs with an interleaver size equal to the REG bundle size. These restrictions may be assumed by the network or indicated to the network by UE 110. Therefore, the network may not transmit and / or expect UE 110 to perform rate matching around LTE CRS for CORESETs configured as described above.

[0047] In a second aspect, example embodiments include example PDCCH DMRS designs. Figure 4 Examples of exemplary PDCCH DMRS designs according to various exemplary embodiments are shown.

[0048] In this example, the PDCCH is configured as three symbols (0-2) in the orthogonal frequency division multiplexing (OFDM) domain 405 and twelve subcarriers (0-11) in the frequency domain 410. Those skilled in the art will appreciate that the PDCCH is not limited to this configuration and may vary in size in the frequency and / or OFDM domain.

[0049] To avoid collisions between NR PDCCH DMRS and LTE CRS, NR PDCCH DMRS can be configured to include one DMRS per three subcarriers in each PDCCH symbol. Therefore, in this example, DMRS exists in three consecutive OFDM symbols because the PDCCH is three OFDM symbols. This configurable RE offset differs from conventional PDCCH DMRS, which is configured to include one DMRS per four subcarriers.

[0050] In addition, the exemplary NR PDCCH DMRS may be configured with a configurable resource element (RE) offset within a resource block (RB). This offset need not be static and may change on a per-RB basis. Thus, at a first time, UE 110 may receive a PDCCH DMRS with an offset of (N) REs. At a second time, UE 110 may receive a PDCCH DMRS with an offset of (M) REs, where (N) is not equal to (M). This configurable RE offset differs from a conventional PDCCH DMRS that is configured with a fixed RE offset of one RE.

[0051] Figure 5Three examples 510 to 530 of LTE CRS transmission and one example 540 of 5G NRPDCCH DMRS transmission according to various exemplary embodiments are shown. The first example 510 shows a one-port CRS transmission. Here, an RE offset of physical cell identity (PCI) mod 6 is utilized. In addition, for symbols 0 and 4 in the OFDM domain 504, the LTE CRS symbol is configured to appear once every six REs in the frequency domain 502. Although in Figure 5 Not shown in FIG, but symbols 7 and 11 may also be configured to include LTE CRS symbols.

[0052] The second example 520 shows a two-port CRS transmission. Here, an RE offset of (PCI mod 6) is used. In addition, the LTE CRS symbol is a symbol that appears every three REs in the frequency domain 502 for time slots 0 and 4 in the OFDM domain 504. Although Figure 5 Not shown in FIG, but symbols 7 and 11 may also be configured to include LTE CRS symbols.

[0053] The third example 530 shows a four-port CRS transmission. Here, an RE offset of (PCI mod 6) is used. In addition, for symbols 0, 1, and 4 in the OFDM domain 504, the LTE CRS symbols are configured to appear once every three REs in the frequency domain 502. Figure 5 Although not shown, symbols 7, 8, and 11 may also be configured to include LTE CRS symbols. The above examples 510 to 530 are provided for illustrative purposes only and are not intended to limit the exemplary embodiments in any way. Rather, examples 510 to 530 provide general examples of three possible LTE CRS arrangements. Those skilled in the art will appreciate that the positions of LTE CRS symbols may be initially configured differently and / or shifted in the OFDM domain over time.

[0054] In some embodiments, to avoid collisions between NR PDCCH DMRS and LTE CRS, the network may configure NR PDCCH DMRS 540 so that it is not present in certain PDCCH symbols. In other words, the network may not configure 5G NR PDCCH DMRS in the frequency and time locations (e.g., REs) to be used for LTE CRS symbols.

[0055] Example 540 illustrates an exemplary 5G NR PDCCH DMRS transmission. The 5G NR PDCCH DMRS illustrated in Example 540 is similar to Figure 4However, the above exemplary techniques may also be applied to legacy PDCCH DMRS configurations and future implementations of PDCCH DMRS configurations.

[0056] The network may configure the 5G NR PDCCH DMRS symbols shown in example 540 so that they are not present in REs configured for LTE CRS transmission. To provide an example within the context of example 510, the network may configure the 5G NR PDCCH DMRS to be located within REs marked as DMRS within box 541, as shown in example 510.

[0057] To provide another example within the context of example 520, the network may configure the 5G NR PDCCH DMRS to be within the REs marked as DMRS within block 542, as shown in example 520. To provide another example within the context of example 530, the network may configure the 5G NR PDCCH DMRS to be within the REs marked as DMRS within block 543, as shown in example 530. As described above, the exemplary PDCCH DMRS may be provided with a configurable RE offset. Therefore, the RE offset shown in block 543 is different from the RE offset shown in blocks 541 and 542.

[0058] Those skilled in the art will appreciate that the exemplary embodiments described above may be implemented with any suitable software configuration or hardware configuration or combination thereof. Exemplary hardware platforms for implementing the exemplary embodiments may include, for example, Intel x86-based platforms with compatible operating systems, Windows OS, Mac platforms and MAC OS, mobile devices with operating systems such as iOS, Android, etc. The exemplary embodiments of the above methods may be embodied as a program comprising lines of code stored on a non-transitory computer-readable storage medium, which, when compiled, may be executed on a processor or microprocessor.

[0059] Although this patent application describes various combinations of various embodiments, each with different features, those skilled in the art will understand that any feature of one embodiment may be combined with features of other embodiments in any manner not publicly denied, or with features that are not functionally or logically inconsistent with the operation or described function of the device of the embodiments disclosed herein.

[0060] It is understood that the use of personally identifiable information should be subject to privacy policies and practices that are generally recognized to meet or exceed industry or government requirements for maintaining user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of authorized use should be clearly stated to users.

[0061] It will be apparent to those skilled in the art that various modifications may be made to the present disclosure without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is intended to cover modifications and variations of the present disclosure provided that these modifications and variations are within the scope of the appended claims and their equivalents.

Claims

1. A baseband processor, the baseband processor being configured to perform operations comprising: receiving information associated with a downlink reference signal for a first radio access technology (RAT), wherein the first RAT is different from a currently camped-on second RAT; identifying a reference signal opportunity for the downlink reference signal; as well as receiving downlink control information from the second RAT via a physical downlink control channel (PDCCH); as well as Generate user equipment (UE) capability information for transmitting to a currently camped cell of the second RAT, the UE capability information indicating that the UE is configured to perform rate matching around an LTE cell-specific reference signal (CRS) during PDCCH reception, and wherein the UE capability information is of a per-band reporting type.

2. The baseband processor of claim 1 , wherein the operations further comprise: identifying a search space for the PDCCH; When the search space is configured after radio resource control (RRC) establishment is completed, upon receiving the downlink control information from the second RAT via the PDCCH, performing rate matching around the downlink reference signal for the first RAT; as well as When the search space is configured before the RRC establishment, rate matching is not performed around the downlink reference signal for the first RAT when the downlink control information is received from the second RAT via the PDCCH.

3. The baseband processor of claim 1 , wherein the operations further comprise: Identifying a control resource set CORESET associated with the PDCCH; when the CORESET is configured after radio resource control (RRC) establishment is completed, performing rate matching around the downlink reference signal for the first RAT when receiving the downlink control information from the second RAT via the PDCCH; as well as When the CORESET is configured before the RRC establishment, rate matching is not performed around the downlink reference signal for the first RAT when the downlink control information is received from the second RAT via the PDCCH.

4. The baseband processor of claim 1 , wherein the operations further comprise: identifying a search space for the PDCCH; when the search space for the PDCCH is a user equipment (UE)-specific search space (USS), performing rate matching around the downlink reference signal for the first RAT when receiving the downlink control information from the second RAT via the PDCCH; as well as When the search space for the PDCCH is a common search space (CSS), rate matching is not performed around the downlink reference signal for the first RAT when the downlink control information is received from the second RAT via the PDCCH.

5. The baseband processor of claim 1 , wherein the operations further comprise: Identifying whether the PDCCH is for licensed spectrum or unlicensed spectrum; performing rate matching around the downlink reference signal for the first RAT when receiving the downlink control information from the second RAT via the PDCCH when the PDCCH is for the licensed spectrum; as well as When a search space is used for the unlicensed spectrum, rate matching is not performed around the downlink reference signal for the first RAT when the downlink control information is received from the second RAT via the PDCCH.

6. The baseband processor of claim 1 , wherein the operations further comprise: identifying that the downlink control information is a type of downlink control information; when the type of downlink control information is downlink control information of a first type, performing rate matching around the downlink reference signal for the first RAT when receiving the downlink control information from the second RAT via the PDCCH, wherein the downlink control information of the first type is non-fallback downlink control information; as well as When the type of downlink control information is second type of downlink control information, rate matching is not performed around the downlink reference signal for the first RAT when the downlink control information is received from the second RAT via the PDCCH, wherein the second type of downlink control information is fallback downlink control information or special downlink control information.

7. The baseband processor of claim 1 , wherein the operations further comprise: identifying that the downlink control information is scrambled with an RNTI associated with the first set of radio network temporary identifiers (RNTIs) or the second set of RNTIs; performing rate matching around the downlink reference signal for the first RAT when receiving the downlink control information from the second RAT via the PDCCH when the RNTI is associated with the first set of RNTIs; as well as When the RNTI is associated with the second set of RNTIs, rate matching is not performed around the downlink reference signal for the first RAT when receiving the downlink control information from the second RAT via the PDCCH.

8. The baseband processor of claim 7, wherein the first set of RNTIs comprises at least one of a cell RNTIC-RNTI, a configuration scheduling CS-RNTI, or a modulation and coding scheme cell RNTIC-RNTI.

9. The baseband processor according to claim 1, wherein the downlink control information is carried via a PDCCH having a demodulation reference signal (DMRS), and wherein For each symbol of the PDCCH, the PDCCH DMRS includes one DMRS resource element RE for every three resource elements RE.

10. A user equipment (UE), comprising: a transceiver configured to communicate with a network; and a processor communicatively coupled to the transceiver and configured to perform operations including: receiving information associated with a downlink reference signal for a first radio access technology (RAT), wherein the first RAT is different from a currently camped-on second RAT; identifying a reference signal opportunity for the downlink reference signal; as well as receiving downlink control information from the second RAT via a physical downlink control channel (PDCCH); as well as Generate UE capability information for transmission to a currently camped cell of the second RAT, the UE capability information indicating that the UE is configured to perform rate matching around an LTE cell-specific reference signal (CRS) during PDCCH reception, and wherein the UE capability information is of a per-band reporting type.

11. The UE according to claim 10, wherein the operations further comprise: A determination is made that a predetermined condition is satisfied, wherein receiving the downlink control information comprises performing rate matching around the downlink reference signal of the first RAT based on the predetermined condition being satisfied.

12. The UE according to claim 10, wherein the operations further comprise: confirming that predetermined conditions are met; When the predetermined condition is met, an indication that the UE supports all consecutive resource blocks is transmitted to the currently camped cell of the second RAT.

13. The UE according to claim 12, wherein the indication further indicates whether the UE supports a control resource set (CORESET) precoder granularity parameter sameAsREG-bundle.

14. The UE according to claim 10, wherein: When a predetermined condition is met, the downlink control information includes a non-interleaved control resource set CORESET.

15. The UE according to claim 10, wherein: When a predetermined condition is satisfied, the downlink control information includes a control resource set CORESET having an interleaver size that is the same as a resource element group REG bundle size.

16. The UE according to claim 10, wherein the downlink control information is carried via a PDCCH having a demodulation reference signal (DMRS), and wherein: For each symbol of the PDCCH, the PDCCH DMRS includes one DMRS resource element RE for every three resource elements RE. 17 . The UE according to claim 10 , wherein the downlink control information is a PDCCH demodulation reference signal (DMRS) including a configurable resource element offset.

18. The UE of claim 10, wherein the downlink control information is carried via a PDCCH having a DMRS including a plurality of demodulation reference signal (DMRS) symbols, and wherein none of the DMRS symbols is located in the same resource element as a downlink reference signal symbol of the first RAT.

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