Dynamic CRS rate matching for NR UEs

Abstract

A technique for dynamic CRS rate matching for NR UEs is provided. The spectrum served by the NR UE at least partially overlaps with the spectrum served by the LTE UE. One method is performed by a network node. The method includes obtaining an MBSFN configuration related to a change in the MBSFN mode for the LTE UE. The MBSFN configuration specifies that in the MBSFN mode, at least one non-MBSFN subframe is replaced by an MBSFN subframe, and / or at least one MBSFN subframe is replaced by a non-MBSFN subframe. The method includes adapting dynamic downlink CRS rate matching for the NR UE in the replaced at least one non-MBSFN subframe or MBSFN subframe. Depending on the change in the MBSFN mode, dynamic downlink CRS rate matching is enabled or disabled in the replaced at least one non-MBSFN subframe or MBSFN subframe.

Description

Technical Field

[0001] The embodiments provided herein relate to methods, network nodes, computer programs, and computer program products for dynamic cell-specific reference signal rate matching for new radio user equipment. Background Technology

[0002] NR (New Radio) is the air interface designated for fifth-generation (5G) telecommunications systems under the 3rd Generation Partnership Project (3GPP). NR can be seen as a further development of the Long Term Evolution (LTE) air interface, with enhanced functionality and performance.

[0003] Mobile network operators deploying NR typically have access to or have been allocated existing spectrum on multiple frequency bands where LTE signaling is currently deployed. Initially, the proportion of user equipment (UEs) with NR capability may be limited compared to LTE-capable UEs, and therefore, most of the existing spectrum may still need to be allocated for LTE signaling.

[0004] There are several architectural options for deploying NR alongside LTE.

[0005] One option is to use LTE as the primary air interface while adding NR using dual connectivity in non-standalone mode. With dual connectivity, both the LTE and NR air interfaces can be used in parallel for data transmission (and reception). In the downlink (i.e., in the direction from the network-side radio access network node towards the user-side UE), data transmission is separated at the Packet Data Convergence Protocol (PDCP) layer and either or both of these air interfaces (i.e., LTE or NR) can be used. In the uplink (i.e., in the direction from the user-side UE towards the network-side radio access network node), data received from both air interfaces is combined at the PDCP layer at the radio access network node.

[0006] To achieve efficient spectrum utilization, NR carriers can be superimposed on the same spectrum as LTE carriers. This is achieved through flexible positioning of control channels and signals, as well as NR rate matching around LTE reference signals transmitted on LTE carriers (such as Cell Specific Reference Signals (CRS), Channel State Information Reference Signals (CSI-RS)), synchronization signals (such as Primary Synchronization Signal (PSS), Secondary Synchronization Signal (SSS)), and the Physical Broadcast Channel (PBCH).

[0007] A side effect of using CRS rate matching to dynamically share spectrum is that the NR Physical Downlink Control Channel (PDCCH) becomes limited to symbols where CRS is not available. This significantly limits the number of UEs that can be scheduled simultaneously and hinders the efficient use of spectrum.

[0008] Furthermore, relying on Radio Resource Control (RRC) signaling to configure NR UEs with CRS rate matching incurs overhead. For example, RRC signaling is required every time a new Multimedia Broadcast Multicast Service Single Frequency Network (MBSFN) configuration is selected. This signaling consumes air interface resources and can cause connectivity problems, particularly for UEs with poor radio conditions.

[0009] Therefore, improvements to the joint downlink NR and LTE transmission are still needed. Summary of the Invention

[0010] The purpose of the embodiments described herein is to provide efficient joint downlink NR and LTE transmission that is unaffected by the aforementioned problems, or at least mitigates or reduces them.

[0011] According to a first aspect, a method for dynamic CRS rate matching for an NR UE is provided. The spectrum served by the NR UE at least partially overlaps with the spectrum served by an LTE UE. The method is performed by a network node. The method includes obtaining an MBSFN configuration related to a change in an MBSFN mode for the LTE UE. The MBSFN mode specifies which subframes are MBSFN subframes and which are non-MBSFN subframes. Separate MBSFN modes exist for the NR UE and the LTE UE. The MBSFN configuration specifies that in the MBSFN mode, at least one non-MBSFN subframe is replaced by an MBSFN subframe, and / or at least one MBSFN subframe is replaced by a non-MBSFN subframe. The method includes adapting dynamic downlink CRS rate matching for the NR UE in the replaced at least one non-MBSFN or MBSFN subframe. Depending on the change in the MBSFN mode, dynamic downlink CRS rate matching is enabled or disabled in the replaced at least one non-MBSFN or MBSFN subframe.

[0012] According to a second aspect, a network node is provided for dynamic CRS rate matching for an NR UE. The spectrum served by the NR UE at least partially overlaps with the spectrum served by an LTE UE. The network node includes processing circuitry. The processing circuitry is configured to cause the network node to obtain an MBSFN configuration related to changes in the MBSFN mode for the LTE UE. The MBSFN mode specifies which subframes are MBSFN subframes and which are non-MBSFN subframes. Separate MBSFN modes exist for the NR UE and the LTE UE. The MBSFN configuration specifies that in the MBSFN mode, at least one non-MBSFN subframe is replaced by an MBSFN subframe, and / or at least one MBSFN subframe is replaced by a non-MBSFN subframe. The processing circuitry is configured to cause the network node to adapt dynamic downlink CRS rate matching for the NR UE in the replaced at least one non-MBSFN or MBSFN subframe. Depending on the change in the MBSFN mode, dynamic downlink CRS rate matching is enabled or disabled in the replaced at least one non-MBSFN or MBSFN subframe.

[0013] According to a third aspect, a network node is provided for dynamic CRS rate matching for an NR UE. The spectrum served by the NR UE at least partially overlaps with the spectrum served by an LTE UE. The network node includes an acquisition module configured to acquire an MBSFN configuration related to changes in the MBSFN mode for the LTE UE. The MBSFN mode specifies which subframes are MBSFN subframes and which are non-MBSFN subframes. Separate MBSFN modes exist for the NR UE and the LTE UE. The MBSFN configuration specifies that in the MBSFN mode, at least one non-MBSFN subframe is replaced by an MBSFN subframe, and / or at least one MBSFN subframe is replaced by a non-MBSFN subframe. The network includes an adaptation module configured to adapt dynamic downlink CRS rate matching for the NR UE in the replaced at least one non-MBSFN or MBSFN subframe. Depending on the change in the MBSFN mode, dynamic downlink CRS rate matching is enabled or disabled in the replaced at least one non-MBSFN or MBSFN subframe.

[0014] According to a fourth aspect, a computer program is provided for dynamic CRS rate matching for an NR UE. The computer program includes computer code that, when executed on the processing circuitry of a network node, causes the network node to perform actions. One action includes the network node obtaining an MBSFN configuration related to a change in the MBSFN mode for the LTE UE. The MBSFN mode specifies which subframes are MBSFN subframes and which are non-MBSFN subframes. Separate MBSFN modes exist for the NR UE and the LTE UE. The MBSFN configuration specifies that in the MBSFN mode, at least one non-MBSFN subframe is replaced by an MBSFN subframe, and / or at least one MBSFN subframe is replaced by a non-MBSFN subframe. One action includes the network node adapting dynamic downlink CRS rate matching for the NR UE in the replaced at least one non-MBSFN or MBSFN subframe. Depending on the change in the MBSFN mode, dynamic downlink CRS rate matching is enabled or disabled in the replaced at least one non-MBSFN or MBSFN subframe.

[0015] According to a fifth aspect, a computer program product is provided, comprising the computer program as described in the fourth aspect and a computer-readable storage medium storing the computer program thereon. The computer-readable storage medium may be a non-transitory computer-readable storage medium.

[0016] Advantageously, these aspects enable efficient joint downlink NR and LTE transmission.

[0017] Advantageously, these aspects enable joint downlink NR and LTE transmissions unaffected by the aforementioned issues.

[0018] Advantageously, even when the MBSFN mode changes, these aspects do not require any additional RRC signaling to configure NR UEs with dynamic CRS rate matching. In turn, these aspects thus improve the spectral efficiency of NR UEs.

[0019] Other objects, features and advantages of the appended embodiments will become apparent from the following detailed disclosure, the appended dependent claims and the accompanying drawings.

[0020] Generally, unless otherwise expressly defined herein, all terms used in the claims shall be interpreted in accordance with their ordinary meaning in the technical field. Unless otherwise expressly stated, all references to “a / an / the element, device, component, part, module, step, etc.” shall be publicly interpreted as referring to at least one instance of the element, device, component, part, module, step. Unless expressly stated otherwise, the steps of any method disclosed herein need not be performed in the exact order disclosed. Attached Figure Description

[0021] The concept of the invention will now be described by way of example with reference to the accompanying drawings, in which:

[0022] Figure 1 This is a schematic diagram illustrating a communication network according to an embodiment;

[0023] Figure 2 This is a block diagram of network nodes according to an embodiment;

[0024] Figure 3 This is a flowchart of the method according to the embodiment;

[0025] Figure 4 The MBSFN pattern according to an embodiment is illustrated schematically;

[0026] Figure 5 This is a schematic diagram illustrating the signaling according to an embodiment;

[0027] Figure 6 This is a flowchart of the method according to the embodiment;

[0028] Figure 7 This is a schematic diagram illustrating the structural units of a network node according to an embodiment;

[0029] Figure 8 This is a schematic diagram illustrating the functional modules of a network node according to an embodiment; and

[0030] Figure 9 An example of a computer program product including a computer-readable storage medium according to an embodiment is shown. Detailed Implementation

[0031] The concept of the invention will now be described in more detail with reference to the accompanying drawings, which illustrate certain embodiments of the concept. However, the concept of the invention can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example to make this disclosure complete and exhaustive, and to fully convey the scope of the concept to those skilled in the art. Throughout the specification, the same reference numerals refer to the same elements. Any step or feature shown in dashed lines should be considered optional.

[0032] Figure 1 This is a schematic diagram illustrating a communication network 100 to which embodiments proposed herein may be applied. The communication network 100 includes a network node 200 configured to provide network access to user equipment (UEs) represented by user equipment (UEs) 150a, 150b, 150c, and 150d in a radio access network 110. The radio access network 110 is operatively connected to a core network 120. The core network 120 is operatively connected to a serving network 130, such as the Internet. Thus, UEs 150a, 150b, 150c, and 150d can access services of the serving network 130 and exchange data with the serving network 130 via the network node 200. Some UEs may be configured to communicate with the network node 200 using only LTE signaling, some UEs may be configured to communicate with the network node 200 using only NR signaling, and some UEs may be configured to communicate with the network node 200 using both LTE and NR signaling. User equipment 150c and 150d, configured to communicate with network node 200 using LTE signaling, are referred to as LTE user equipment hereinafter. User equipment 150a and 150b, configured to communicate with network node 200 using NR signaling, are referred to as NR user equipment hereinafter.

[0033] Network node 200 includes an antenna system containing co-located antenna arrays 140a and 140b, and co-located, integrated with, or operationally communicates with the antenna system. Each of antenna arrays 140a and 140b may include multiple individual antennas or antenna elements. In some implementations, one antenna array 140b may be configured for LTE signaling, while the other antenna arrays 140a may be configured for NR signaling. In other implementations, antenna arrays 140a and 140b are configured for both LTE and NR signaling.

[0034] Examples of network nodes 200 include radio access network nodes, radio base stations, base transceivers, Node B, evolved Node B, gNB, access points, access nodes, transmission points and receiving points, and integrated access and backhaul nodes. Examples of user equipment 150a, 150b, 150c, and 150d include terminal equipment, wireless devices, mobile stations, mobile phones, handheld devices, wireless local loop phones, smartphones, laptop computers, tablet computers, networked sensors, networked vehicles, and so-called Internet of Things (IoT) devices.

[0035] As mentioned above, improvements to the joint downlink NR and LTE transmission are still needed.

[0036] Therefore, the embodiments disclosed herein relate to techniques for dynamic CRS rate matching for NR UEs 150a and 150b. To obtain such techniques, a network node 200, a method executed by the network node 200, and a computer program product including code (e.g., in the form of a computer program) that, when run on the network node 200, causes the network node 200 to execute the method.

[0037] Figure 2 A block diagram of a network node 200 is schematically shown, comprising a shared resource allocator 240, an LTE scheduler 242, and an NR scheduler 244, as well as an LTE transmitter 246 and an NR transmitter 248. The LTE transmitter 246 may include or be operatively connected to at least an antenna array 140b. The NR transmitter 248 may include or be operatively connected to at least an antenna array 140a. The shared resource allocator 240 is configured to make decisions regarding when to perform dynamic CRS RM for NR UEs 150a and 150b based on inputs from the LTE scheduler 242 and the NR scheduler 244, as shown in step S104 below. Downlink subframe transmission is initiated by the shared resource allocator 240, which provides outputs to the LTE scheduler 242 and the NR scheduler 244. The output to the LTE scheduler 242 is defined by the scheduling decision for the LTE UE. The output to the NR scheduler 244 is defined by the information in step S104. LTE scheduler 242 is configured to schedule LTE transmissions and initiate LTE transmissions from LTE transmitter 246 based on the output received from shared resource allocator 240. NR scheduler 244 is configured to schedule NR transmissions and initiate NR transmissions from NR transmitter 248 based on the output received from shared resource allocator 240.

[0038] Figure 3 This is a flowchart illustrating an embodiment of a method for dynamic CRS rate matching for NR UEs 150a and 150b. The spectrum served by NR UEs 150a and 150b at least partially overlaps with the spectrum served by LTE UEs 150c and 150d. These methods are performed by network node 200. These methods are advantageously provided as computer program 920.

[0039] Assume that the initial MBSFN mode is configured for NR UEs 150a and 150b and LTE UEs 150c and 150d. For LTE UEs 150c and 150d, the MBSFN subframe is a subframe where the LTE PDSCH is not transmitted. Figure 4Three examples of MBSFN modes 400a, 400b, and 400c are shown. LTE UEs 150c and 150d can be configured with the initial MBSFN mode via system information broadcast, while NR UEs 150a and 150b can be configured with the initial MBSFN mode during UE connection establishment signaling.

[0040] It is also assumed that a decision has been made to change the MBSFN allocation for LTE UEs 150c and 150d. In some respects, this decision is made by the shared resource allocator 240.

[0041] S102: Therefore, network node 200 obtains the MBSFN configuration related to the changes in MBSFN modes 400a, 400b, and 400c for LTE UEs 150c and 150d.

[0042] MBSFN modes 400a, 400b, and 400c specify which subframes are MBSFN subframes (420) and which are non-MBSFN subframes (410). For example... Figure 4 As can be further seen, NR UEs 150a and 150b and LTE UEs 150c and 150d do not necessarily share the same view of MBSFN mode. Therefore, separate MBSFN modes 400a, 400b, and 400c exist for NR UEs 150a and 150b and LTE UEs 150c and 150d.

[0043] The MBSFN configuration specifies that in MBSFN modes 400a, 400b, and 400c, at least one non-MBSFN subframe 410 is replaced by an MBSFN subframe 420, and / or at least one MBSFN subframe 420 is replaced by a non-MBSFN subframe 410.

[0044] Both LTE scheduler 242 and NR scheduler 244 were notified of the change.

[0045] S104: Network node 200 adapts dynamic downlink CRS rate matching for NR UE 150a, 150b in at least one replaced non-MBSFN subframe 410 or MBSFN subframe 420. Depending on the changes in MBSFN modes 400a, 400b, 400c, dynamic downlink CRS rate matching is enabled or disabled in at least one replaced non-MBSFN frame 410 or MBSFN subframe 420.

[0046] Generally, rate matching is achieved by instructing NR UEs 150a and 150b whether to perform rate matching around a resource element (RE) using downlink control information (DCI; such as scheduling allocation). When NR UEs 150a and 150b are configured not to perform rate matching, they know that the RE contains PDSCH data, and therefore, they decode these REs accordingly.

[0047] Implementations relating to further details of dynamic CRS rate matching for NR UEs 150a and 150b performed by network node 200 will now be disclosed.

[0048] The changes to MBSFN modes 400a, 400b, and 400c can take different forms. In some embodiments, in any subframe of MBSFN modes 400a, 400b, and 400c used for NR UEs 150a and 150b, including MBSFN subframe 420, only MBSFN modes 400a, 400b, and 400c used for LTE UEs 150c and 150d are changed. Figure 4 The example in the text is an example of this.

[0049] The following will disclose how network node 200 adapts dynamic downlink CRS rate matching for NR UE 150a, 150b in at least one replaced non-MBSFN subframe 410 or MBSFN subframe 420.

[0050] In some aspects, the number of MBSFNs is increased (thus, changing from MBSFN mode 400a to MBSFN mode 400b, or from MBSFN mode 400b to MBSFN mode 400c). NR UEs 150a and 150b then do not have dynamic CRS rate matching on the new MBSFN subframe 420. That is, in some embodiments, in response to at least one non-MBSFN subframe 410 being replaced by MBSFN subframe 420, the adaptation includes disabling dynamic CRS rate matching for NR UEs 150a and 150b in at least one non-MBSFN subframe 410 that is replaced by MBSFN subframe 420.

[0051] In this regard, it takes some time for all LTE UEs 150c and 150d to be configured with the new MBSFN mode. During this period, NR UEs 150a and 150b can be configured to use dynamic CRS rate matching on the new MBSFN subframes. When all LTE UEs 150c and 150d have been notified of the new MBSFN mode, NR UEs 150a and 150b are scheduled in these MBSFN subframes without dynamic CRS rate matching. Therefore, in some aspects, dynamic CRS rate matching is only used on the new MBSFN subframe 420 during the time it takes for LTE UEs 150c and 150d to be configured with the new MBSFN configuration. That is, in some embodiments, in at least one replaced non-MBSFN subframe 410, dynamic CRS rate matching for NR UEs 150a and 150b remains on for the period of time it takes for LTE UEs 150c and 150d to be configured with the MBSFN configuration, and then is turned off.

[0052] In some aspects, the number of MBSFNs is reduced (thus, changing from MBSFN mode 400c to MBSFN mode 400b, or from MBSFN mode 400b to MBSFN mode 400a). Dynamic CRS rate matching for NR UEs 150a and 150b can then begin on the new non-MBSFN subframe 410. That is, in some embodiments, in response to at least one MBSFN subframe 420 being replaced by a non-MBSFN subframe 410, the adaptation includes: enabling dynamic CRS rate matching for NR UEs 150a and 150b in at least one MBMS subframe 420 that has been replaced by a non-MBSFN subframe 410.

[0053] In some aspects, dynamic CRS rate matching only begins after the new MBSFN configuration takes effect in LTE UEs 150c and 150d. That is, in some embodiments, dynamic CRS rate matching for NR UEs 150a and 150b remains off in at least one MBSFN subframe 420 that is replaced, until after the time period spent configuring the MBSFN for LTE UEs 150c and 150d, and then is enabled.

[0054] Next, we will disclose aspects of spectrum sharing between NR UEs 150a and 150b and LTE UEs 150c and 150d.

[0055] In some aspects, in non-MBSFN subframes, NR UEs 150a and 150b are allocated a spectrum share greater than half the bandwidth. Specifically, in some embodiments, non-MBSFN subframe 410 occupies bandwidth in the spectrum, and NR UEs 150a and 150b are allocated at least one share of the spectrum, and this share is greater than half the bandwidth of non-MBSFN subframe 410. Furthermore, in some embodiments, when at least one LTE UE 150c or 150d is served, time / frequency resources from the portion of the spectrum where dynamic CRS rate matching is performed are allocated to at least one LTE UE 150c or 150d. Different strategies can exist for allocating time / frequency resources. One strategy is to maximize NR efficiency. Then, time / frequency resources for NR UEs 150a and 150b are placed in the portion of the spectrum where rate matching is not performed, and time / frequency resources for LTE UEs 150c and 150d are placed in the portion of the spectrum where rate matching is performed. Another strategy is to maximize CRS. Then, the time / frequency resources for NR UEs 150a and 150b are placed in the portion of the spectrum where rate matching is performed, and the time / frequency resources for LTE UEs 150c and 150d are placed in the portion of the spectrum where rate matching is not performed. In other words, when CRS is transmitted across the entire spectrum, but rate matching in NR is only performed on a portion of the spectrum, NR UEs 150a and 150b are scheduled in the portion of the spectrum where rate matching is performed, while LTE UEs 150c and 150d are scheduled in another portion of the spectrum. Furthermore, in some embodiments, when at least one NR UE 150a and 150b and at least one LTE UE 150c and 150d are served, the CRS allocated for at least one LTE UE 150c and 150d is punctured in the portion of the spectrum where dynamic CRS rate matching is not performed.

[0056] In some aspects, it is ensured that LTE UEs 150c and 150d always have sufficient PRBs to perform their receiver operations. This can be achieved by transmitting CRS on a sufficient series of PRBs, where the minimum of this series of PRBs can be adaptively determined. Therefore, in some embodiments, when at least one NR UE 150a and 150b and at least one LTE UE 150c and 150d are served, the minimum amount of time / frequency resources for the CRS allocated to at least one LTE UE 150c and 150d is adaptively determined. Different adaptive methods exist. For example, an adaptive method might involve attempting LTE PDSCH transmissions on a series of PRBs and observing HARQ feedback from at least one LTE UE 150c and 150d. Specifically, in some embodiments, adaptively determining the minimum amount of time / frequency resources includes observing HARQ feedback from at least one LTE UE 150c and 150d in response to downlink data or control transmissions to at least one LTE UE 150c and 150d.

[0057] Next, we will disclose how dynamic rate matching is achieved.

[0058] Generally, NR UEs 150a and 150b need to perform rate matching around the CRS transmitted in normal subframes by LTE (regardless of whether these subframes have been normal subframes for a long time (i.e., non-MBSFN subframes) or whether they have recently transitioned from MBSFN subframes to normal subframes). However, the capacity of NR to signal alternative rate matching modes to NR UEs 150a and 150b is limited. By coordinating the NR CSI-RS mode to at least partially overlap with the LTE CRS mode, ZP-CSI-RS (where ZP is an abbreviation for zero power) can perform NR rate matching around the LTE CRS. Therefore, in some embodiments, using dynamic CRS rate matching includes using ZP-CSI-RS rate matching. In this way, NR UEs 150a and 150b can be configured to use ZP-CSI-RS to perform dynamic rate matching around the LTE CRS so that it can cover the maximum possible number of CRS REs. In some embodiments, if supported by NR UEs 150a and 150b, dynamic CRS rate matching includes using rateMatchingResrcSetDynamic (UE feature 5-27) rate matching and / or separateCRS-RateMatching-r16 (UE feature 16-2a-5) rate matching. Furthermore, whether to trigger rateMatchingResrcSetDynamic or separateCRS-RateMatching-r16 depends on the value of the minimum LTE CRS PRB. Therefore, in some embodiments, triggering rateMatchingResrcSetDynamic or separateCRS-RateMatching-r16 rate matching depends on the minimum amount of time / frequency resources determined above. One variation is to additionally configure static CRS rate matching for NR UEs 150a and 150b, but only on CRS Port_o, or on all ports of the middle 6 PRBs. Another variation is to configure maximum CRS rate matching and / or ZP-CSI-RS rate matching for NR UE 150a and 150b.

[0059] Next reference Figure 5 Signaling diagram.

[0060] S201a, S201b: The LTE scheduler and NR scheduler are configured with initial MBSFN modes, and these MBSFN modes are made known to the shared resource allocator. The LTE scheduler notifies the LTE UE of the (LTE) MBSFN modes via system information broadcast. The NR scheduler configures the NR UE with (NR) MBSFN modes and configures the NR UE with dynamic rate matching.

[0061] S202: The shared resource allocator determines whether dynamic rate matching should be used and sends the dynamic rate matching decision to the NR scheduler. The NR scheduler sends a PDSCH with or without dynamic rate matching.

[0062] S203: The shared resource allocator decides to change the MBSFN mode used by the LTE UE and transmits the new MBSFN mode to the LTE scheduler. The MBSFN mode is changed such that in the MBSFN mode used by the LTE UE, at least one non-MBSFN subframe is replaced by an MBSFN subframe, and / or at least one MBSFN subframe is replaced by a non-MBSFN subframe. The LTE scheduler notifies the LTE UE of the new MBSFN mode via system information broadcast.

[0063] S204: Based on the modified MBSFN mode, the shared resource allocator adapts dynamic downlink CRS rate matching for the NR UE in at least one replaced non-MBSFN or MBSFN subframe and notifies the NR scheduler of this situation. The NR scheduler accordingly adapts its PDSCH transmissions with or without dynamic rate matching.

[0064] S205: Based on the HARQ feedback received from the LTE UE, the LTE scheduler updates the minimum number of PRBs for CRS and notifies the shared resource allocator of the minimum number of PRBs for CRS.

[0065] S206: Based on the information received from the LTE scheduler, the shared resource allocator determines to update CRS transmissions and dynamic rate matching. The shared resource allocator notifies the LTE scheduler of CRS transmissions and the NR scheduler of dynamic rate matching. The LTE scheduler schedules CRS transmissions accordingly. The NR scheduler transmits PDSCHs based on the dynamic rate matching decision.

[0066] Generally, rateMatchingResrcSetDynamic or separateCRS-RateMatching-r16 or any similar rate matching capability allows CRS transmission over the full LTE bandwidth. In cases where the NR UE does not support any of these optional capabilities and is allocated a spectrum share greater than half the bandwidth in a non-MBSFN subframe, a method based on... Figure 6 The process of creating a flowchart.

[0067] S301: The minimum number of PRBs that will be sent on the LTE scheduler's initial CRS. This minimum number can be zero if LTE UEs 150c and 150d are not present. Analyze feedback from LTE UEs 150c and 150d. This can be HARQ feedback or Channel State Information (CSI) regarding control or data channels, or any other parameters reported by the UE.

[0068] S302: Based on the received feedback, the minimum number of PRBs that the CRS will send on it will be adjusted. If the HARQ feedback is an acknowledgment (ACK), the number can be decreased. If the feedback is not an ACK (i.e., a negative acknowledgment, NACK), the number can be increased. Similar actions can be performed on other types of received feedback.

[0069] S303: Check whether the minimum number of PRBs that will be transmitted on the CRS is less than or equal to the number of PRBs covered by ZP-CSI-RS rate matching set 1 (Set1). Set 1 is a ZP-CSI-RS resource set that only covers REs of the LTE CRS. However, this set is limited to half the LTE bandwidth, above or below the LTE DC carrier.

[0070] S304: The NR scheduler uses ZP-CSI-RS rate matching set 1 to transmit PDSCH with dynamic rate matching. The LTE scheduler does not transmit CRS on PRBs not covered by ZP-CSI-RS rate matching set 1.

[0071] S305: If the minimum number of PRBs that the CRS will transmit on it is greater than the number of PRBs covered by ZP-CSI-RS rate matching set 1, then check whether NR UE 150a, 150b is configured with any other dynamic rate matching capabilities, such as rateMatchingResrcSetDynamic or separateCRS-RateMatching-r16, or any similar rate matching capabilities that allow CRS transmission over the full LTE bandwidth.

[0072] S306: Check whether NR UE 150a and 150b are configured with any such dynamic rate matching capabilities, and whether the NR PDSCH can maximize its transport block size (TBS) by utilizing these capabilities compared to ZP-CSI-RS rate matching set 2. Set 2 is a ZP-CSI-RS resource set that covers more REs than LTE CRS. However, this set can cover the entire LTE bandwidth.

[0073] S307: The NR scheduler uses dynamic rate matching capability to perform CRS rate matching. The LTE scheduler transmits CRS on all LTE PRBs.

[0074] S308: Check whether NR UE 150a and 150b are configured with any other dynamic rate matching capabilities, and that NR PDSCH maximizes its TBS through ZP-CSI-RS rate matching set 2 compared to ZP-CSI-RS rate matching set 1.

[0075] S309: The NR scheduler uses ZP-CSI-RS rate matching set 2 to perform CRS rate matching. The LTE scheduler transmits CRS on all LTE PRBs.

[0076] S310: The NR scheduler uses ZP-CSI-RS rate matching set 1 to perform CRS rate matching and is limited to using PRBs covered by ZP-CSI-RS rate matching set 1. The LTE scheduler transmits CRS on all LTE PRBs.

[0077] Figure 7 The components of a network node 200 according to an embodiment are schematically shown in multiple structural units. The processing circuitry 210 uses a product 910 capable of executing a computer program stored therein (such as...). Figure 9 As shown, for example, in the form of storage medium 230, the software instructions are provided as any combination of one or more of a suitable central processing unit (CPU), multiprocessor, microcontroller, digital signal processor (DSP), etc. The processing circuitry 210 may also be provided as at least one application-specific integrated circuit (ASIC) or field-programmable gate array (FPGA).

[0078] Specifically, the processing circuit 210 is configured to cause the network node 200 to perform the set of operations or steps described above. For example, the storage medium 230 may store the set of operations, and the processing circuit 210 may be configured to retrieve the set of operations from the storage medium 230 to cause the network node 200 to perform the set of operations. The set of operations may be provided as a set of executable instructions.

[0079] Therefore, the processing circuitry 210 is thus arranged to perform the methods disclosed herein. The storage medium 230 may also include a persistent storage device, for example, any one or a combination of magnetic storage, optical storage, solid-state storage, or even remotely mounted storage. The network node 200 may also include a communication interface 220, which is at least configured for communicating with other entities, functions, nodes, and devices, such as... Figure 1As shown. Therefore, communication interface 220 may include one or more transmitters and receivers, including analog and digital components. Processing circuitry 210 controls the general operation of network node 200, for example by sending data and control signals to communication interface 220 and storage medium 230, by receiving data and reports from communication interface 220, and by retrieving data and instructions from storage medium 230. Other components and related functions of network node 200 are omitted to avoid obscuring the concepts presented herein.

[0080] Figure 8 The components of the network node 200 according to an embodiment are schematically shown in multiple functional modules. Figure 8 The network node 200 includes multiple functional modules: an acquisition module 210a configured to perform step S102 and an adaptation module 210b configured to perform step S104. Figure 8 The network node 200 may also include multiple optional functional modules, such as functional module 210c. Generally, in one embodiment, each functional module 210a:210c may be implemented solely in hardware, while in another embodiment, it may be implemented with the aid of software; that is, the latter embodiment has computer program instructions stored on storage medium 230, which, when run on processing circuitry, cause the network node 200 to perform the aforementioned combined... Figure 8 The corresponding steps mentioned. It should also be mentioned that even though these modules correspond to parts of a computer program, they do not need to be separate modules; however, their implementation in the software depends on the programming language used. Preferably, one or more or all functional modules 210a:210c can be implemented by processing circuitry 210, possibly cooperating with communication interface 220 and / or storage medium 230. Therefore, processing circuitry 210 can be configured to retrieve instructions provided by functional modules 210a:210c from storage medium 230 and execute those instructions, thereby performing any of the steps disclosed herein.

[0081] Network node 200 can be provided as a standalone device or as part of at least one other device. For example, network node 200 can be located in a node of a radio access network or a node of a core network. Alternatively, the functionality of network node 200 can be distributed among at least two devices or nodes. These at least two nodes or devices can be part of the same network segment (such as a radio access network or a core network) or distributed among at least two such network segments. Generally, instructions that need to be executed in real time can be executed in devices or nodes that are operationally closer to the cell than instructions that do not need to be executed in real time. Thus, a first part of the instructions executed by network node 200 can be executed in a first device, while a second part of the instructions executed by network node 200 can be executed in a second device; the embodiments disclosed herein are not limited to any particular number of devices on which the instructions executed by network node 200 can be executed. Therefore, the methods according to the embodiments disclosed herein are suitable for execution by network node 200 residing in a cloud computing environment. Therefore, although Figure 7 A single processing circuit 210 is shown, but processing circuits 210 can be distributed across multiple devices or nodes. The same applies to… Figure 8 Functional modules 210a: 210c and Figure 9 Computer program 920.

[0082] Some (radio) access network architectures define network nodes (or gNBs), which include multiple components or nodes: a central unit (CU), one or more distributed units (DUs), and one or more radio units (RUs). The protocol layer stack of a network node is partitioned among the CUs, DUs, and RUs, where one or more lower layers of the stack are implemented in the RUs, and one or more higher layers are implemented in the CUs and / or DUs. A CU is coupled to a DU via a fronthaul higher layer separation (HLS) network; a CU / DU is connected to a RU via a fronthaul lower layer separation (LLS) network. In some embodiments, a DU may be combined with a CU, wherein the combined DU / CU may be referred to as a CU or simply a baseband unit. The communication link used to transmit user data messages or packets between the RU and the baseband unit, CU, or DU is called a fronthaul network or interface. Messages or packets may be sent from network node 200 in the downlink (i.e., from CU to RU) or received by network node 200 in the uplink (i.e., from RU to CU).

[0083] Figure 9An example of a computer program product 910 including a computer-readable storage medium 930 is shown. A computer program 920 may be stored on this computer-readable storage medium 930, which can cause processing circuitry 210 and entities and devices operatively coupled thereto (such as communication interface 220 and storage medium 230) to perform the methods according to the embodiments described herein. Therefore, computer program 920 and / or computer program product 910 can provide components for performing any steps disclosed herein.

[0084] exist Figure 9 In the example, computer program product 910 is shown as an optical disc, such as a CD (Optical Disc), DVD (Digital Multifunction Disc), or Blu-ray Disc. Computer program product 910 can also be embodied as memory, such as random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), or electrically erasable programmable read-only memory (EEPROM), and more specifically, as a non-volatile storage medium of a device in external memory, such as USB (Universal Serial Bus) memory or flash memory, such as compact flash memory. Therefore, although computer program 920 is schematically shown herein as a track on the depicted optical disc, computer program 920 can be stored in any manner suitable for computer program product 910.

[0085] The concept of the present invention has been described above primarily with reference to several embodiments. However, as will be readily understood by those skilled in the art, other embodiments besides those disclosed above are also possible within the scope of the concept of the present invention as defined in the appended claims.

Claims

1. A method for dynamic CRS rate matching for NR UEs (150a, 150b), wherein, The spectrum served by the NR UE (150a, 150b) at least partially overlaps with the spectrum served by the LTE UE (150c, 150d), wherein the method is performed by a network node (200), and wherein the method includes: (S102) Obtain (S102) the MBSFN configuration related to the changes in MBSFN modes (400a, 400b, 400c) used for the LTE UEs (150c, 150d). The MBSFN modes (400a, 400b, 400c) specify which subframes are MBSFN subframes (420) and which are non-MBSFN subframes (410). Separate MBSFN modes (400a, 400b, 400c) exist for the NR UE (150a, 150b) and the LTE UE (150c, 150d). Wherein, the MBSFN configuration specifies that in the MBSFN modes (400a, 400b, 400c), at least one non-MBSFN subframe (410) is replaced by an MBSFN subframe (420), and / or at least one MBSFN subframe (420) is replaced by a non-MBSFN subframe (410); and In the replaced at least one non-MBSFN subframe (410) or MBSFN subframe (420), adaptation (S104) is performed for dynamic downlink CRS rate matching of the NR UE (150a, 150b), wherein, depending on the change of the MBSFN mode (400a, 400b, 400c), dynamic downlink CRS rate matching is enabled or disabled in the replaced at least one non-MBSFN subframe (410) or MBSFN subframe (420).

2. The method according to claim 1, wherein, In any subframe of the MBSFN mode (400a, 400b, 400c) used for the NR UE (150a, 150b), the MBSFN mode (400a, 400b, 400c) used for the LTE UE (150c, 150d) is changed only for the LTE UE (150c, 150d).

3. The method according to claim 1 or 2, wherein, In response to at least one non-MBSFN subframe (410) being replaced by an MBSFN subframe (420), the adaptation includes: disabling the dynamic CRS rate matching for the NR UE (150a, 150b) in the at least one non-MBSFN subframe (410) that was replaced by the MBSFN subframe (420).

4. The method according to claim 3, wherein, In the replaced at least one non-MBSFN subframe (410), the dynamic CRS rate matching for the NR UE (150a, 150b) remains on for the period of time during which the LTE UE (150c, 150d) is configured with the MBSFN configuration, and is then turned off.

5. The method according to claim 1 or 2, wherein, In response to at least one MBSFN subframe (420) being replaced by a non-MBSFN subframe (410), the adaptation includes: in the at least one MBSFN subframe (420) that was replaced by the non-MBSFN subframe (410), enabling the dynamic CRS rate matching for the NR UE (150a, 150b).

6. The method according to claim 5, wherein, In the replaced at least one MBSFN subframe (420), the dynamic CRS rate matching for the NR UE (150a, 150b) remains off until after the time period spent configuring the MBSFN for the LTE UE (150c, 150d), and then is enabled.

7. The method according to any one of the preceding claims, wherein, The non-MBSFN subframe (410) occupies bandwidth in the spectrum, wherein the NR UE (150a, 150b) is allocated at least one share of the spectrum, wherein the share is greater than half of the bandwidth of the non-MBSFN subframe (410).

8. The method according to claim 7, wherein, When at least one LTE UE (150c, 150d) is being served, a portion of the time / frequency resources from the spectrum from which the dynamic CRS rate matching is performed is allocated to the at least one LTE UE (150c, 150d).

9. The method according to claim 7, wherein, When at least one NR UE (150a, 150b) and at least one LTE UE (150c, 150d) are served, the CRS allocated for the at least one LTE UE (150c, 150d) is punched in the portion of the spectrum where the dynamic CRS rate matching is not performed.

10. The method according to any one of claims 7 to 9, wherein, When at least one NR UE (150a, 150b) and at least one LTE UE (150c, 150d) are being served, the minimum amount of time / frequency resources of CRS allocated for the at least one LTE UE (150c, 150d) is adaptively determined.

11. The method according to claim 10, wherein, Adaptively determining the minimum number includes: observing HARQ feedback from the at least one LTE UE (150c, 150d) in response to downlink data or control transmissions to the at least one LTE UE (150c, 150d).

12. The method according to any one of the preceding claims, wherein, Using the dynamic CRS rate matching includes: using ZP-CSI-RS rate matching.

13. The method according to any one of the preceding claims, wherein, Using the dynamic CRS rate matching includes: using rateMatchingResrcSetDynamic rate matching or separateCRS-RateMatching-r16 rate matching.

14. The method according to a combination of claims 10 and 13, wherein, Whether rateMatchingResrcSetDynamic or separateCRS-RateMatching-r16 rate matching is triggered depends on the minimum number.

15. A network node (200) for dynamic CRS rate matching for NR UEs (150a, 150b), wherein, The spectrum served by the NR UE (150a, 150b) at least partially overlaps with the spectrum served by the LTE UE (150c, 150d), and the network node (200) includes processing circuitry (210) configured to cause the network node (200): Obtain the MBSFN configuration related to the changes in MBSFN modes (400a, 400b, 400c) used for the LTE UEs (150c, 150d). The MBSFN modes (400a, 400b, 400c) specify which subframes are MBSFN subframes (420) and which are non-MBSFN subframes (410). Separate MBSFN modes (400a, 400b, 400c) exist for the NR UE (150a, 150b) and the LTE UE (150c, 150d). Wherein, the MBSFN configuration specifies that in the MBSFN modes (400a, 400b, 400c), at least one non-MBSFN subframe (410) is replaced by an MBSFN subframe (420), and / or at least one MBSFN subframe (420) is replaced by a non-MBSFN subframe (410); and In the replaced at least one non-MBSFN subframe (410) or MBSFN subframe (420), dynamic downlink CRS rate matching is adapted for the NRUE (150a, 150b), wherein, depending on the change of the MBSFN mode (400a, 400b, 400c), dynamic downlink CRS rate matching is enabled or disabled in the replaced at least one non-MBSFN subframe (410) or MBSFN subframe (420).

16. A network node (200) for dynamic CRS rate matching for NR UEs (150a, 150b), wherein, The spectrum served by the NR UE (150a, 150b) at least partially overlaps with the spectrum served by the LTE UE (150c, 150d), and the network node (200) includes: The module (210a) is configured to obtain the MBSFN configuration related to the changes in the MBSFN mode (400a, 400b, 400c) used for the LTE UEs (150c, 150d). The MBSFN modes (400a, 400b, 400c) specify which subframes are MBSFN subframes (420) and which are non-MBSFN subframes (410). Separate MBSFN modes (400a, 400b, 400c) exist for the NR UE (150a, 150b) and the LTE UE (150c, 150d). Wherein, the MBSFN configuration specifies that in the MBSFN modes (400a, 400b, 400c), at least one non-MBSFN subframe (410) is replaced by an MBSFN subframe (420), and / or at least one MBSFN subframe (420) is replaced by a non-MBSFN subframe (410); and An adaptation module (210b) is configured to adapt dynamic downlink CRS rate matching for the NR UE (150a, 150b) in the replaced at least one non-MBSFN subframe (410) or MBSFN subframe (420), wherein dynamic downlink CRS rate matching is enabled or disabled in the replaced at least one non-MBSFN subframe (410) or MBSFN subframe (420) depending on the change in the MBSFN mode (400a, 400b, 400c).

17. The network node (200) according to claim 15 or 16 is further configured to perform the method according to any one of claims 2 to 14.

18. A computer program (920) for dynamic CRS rate matching for NR UEs (150a, 150b), wherein, The spectrum served by the NR UE (150a, 150b) at least partially overlaps with the spectrum served by the LTE UE (150c, 150d), and the computer program includes computer code that, when executed on the processing circuitry (210) of the network node (200), causes the network node (200) to: (S102) Obtain (S102) the MBSFN configuration related to the changes in MBSFN modes (400a, 400b, 400c) used for the LTE UEs (150c, 150d). The MBSFN modes (400a, 400b, 400c) specify which subframes are MBSFN subframes (420) and which are non-MBSFN subframes (410). Separate MBSFN modes (400a, 400b, 400c) exist for the NR UE (150a, 150b) and the LTE UE (150c, 150d). Wherein, the MBSFN configuration specifies that in the MBSFN modes (400a, 400b, 400c), at least one non-MBSFN subframe (410) is replaced by an MBSFN subframe (420), and / or at least one MBSFN subframe (420) is replaced by a non-MBSFN subframe (410); and In the replaced at least one non-MBSFN subframe (410) or MBSFN subframe (420), adaptation (S104) is performed for dynamic downlink CRS rate matching of the NR UE (150a, 150b), wherein, depending on the change of the MBSFN mode (400a, 400b, 400c), dynamic downlink CRS rate matching is enabled or disabled in the replaced at least one non-MBSFN subframe (410) or MBSFN subframe (420).

19. A computer program product (910) comprising a computer program (920) according to claim 18 and a computer-readable storage medium (930) storing the computer program thereon.

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