Patent Application
20240098611
The present disclosure relates to inter-Secondary Node (SN) conditional reconfiguration and associated measurement configuration in a cellular communications network.
A solution for Conditional Primary Secondary Cell (PSCell) Change (CPC) procedure was standardized in Third Generation Partnership Project (3GPP) Release 16 (Rel-16). Therein, a User Equipment (UE) operating in Multi-Radio Dual Connectivity (MR-DC) receives, in a conditional reconfiguration, one or multiple Radio Resource Control (RRC) Reconfiguration(s) (e.g. an RRCReconfiguration message) containing a Secondary Cell Group (SCG) configuration (e.g. an secondaryCellGroup of Information Element (IE) CellGroupConfig) with a reconfigurationWithSync that is stored and associated to an execution condition (e.g. a condition like an A3/A5 event configuration). One of the stored messages is applied only upon the fulfillment of the execution condition, e.g. associated with the serving PSCell, upon which the UE would perform PSCell change (in case it find a neighbor cell that is better than the current Special Cell (SpCell) of the SCG). In the following, some of the steps of CPC Rel-16 as standardized in 3GPP Technical Specification (TS) 37.340 (see, e.g., V16.4.0) are shown, for intra-Secondary Node (SN) CPC.
In 3GPP Release 17 (Rel-17), it has been agreed to extend CPC to the inter-SN case. So far, the following has been agreed in RAN2 #112e:
Bulk Agreement
Per-UE or per-frequency range (FR) measurement gaps can be configured, depending on UE capability to support independent FR measurement and network preference. Per-UE gap applies to both Frequency Range 1 (FR1) (E-UTRA, UTRA-Frequency Division Duplexing (FDD), and NR) and Frequency Range 2 (FR2) (NR) frequencies. For per-FR measurement gap configuration, two independent gap patterns (i.e., FR1 gap and FR2 gap) are configured for FR1 and FR2 respectively. The UE may also be configured with a per-UE gap sharing configuration (applying to per-UE gap) or with two separate gap sharing configurations (applying to FR1 and FR2 measurement gaps respectively).
A measurement gap configuration is always provided:
If per-UE gap is used, the MN decides the gap pattern and the related gap sharing configuration. If per-FR gap is used, in EN-DC and NGEN-DC, the MN decides the FR1 gap pattern and the related gap sharing configuration for FR1, while the SN decides the FR2 gap pattern and the related gap sharing configuration for FR2; in NE-DC and NR-DC, the MN decides both the FR1 and FR2 gap patterns and the related gap sharing configurations.
In EN-DC and NGEN-DC, the measurement gap configuration from the MN to the UE indicates if the configuration from the MN is a per-UE gap or an FR1 gap configuration. The MN also indicates the configured per-UE or FR1 measurement gap pattern and the gap purpose (per-UE or per-FR1) to the SN. Measurement gap configuration assistance information can be exchanged between the MN and the SN. For the case of per-UE gap, the SN indicates to the MN the list of SN configured frequencies in FR1 and FR2 measured by the UE. For the per-FR gap case, the SN indicates to the MN the list of SN configured frequencies in FR1 measured by the UE and the MN indicates to the SN the list of MN configured frequencies in FR2 measured by the UE.
In NE-DC, the MN indicates the configured per-UE or FR1 measurement gap pattern to the SN. The SN can provide a gap request to the MN, without indicating any list of frequencies.
In NR-DC, the MN indicates the configured per-UE, FR1 or FR2 measurement gap pattern and the gap purpose to the SN. The SN can indicate to the MN the list of SN configured frequencies in FR1 and FR2 measured by the UE.
In (NG)EN-DC and NR-DC, SMTC can be used for PSCell addition/PSCell change to assist the UE in finding the SSB in the target PSCell. In case the SMTC of the target PSCell is provided by both MN and SN it is up to UE implementation which one to use.
Measurement gap coordination is assisted by inter-node RRC messages, as follows:
CG-ConfigInfo: This message is used by master evolved Node B (eNB) or next generation Node B (gNB) to request the Secondary gNB (SgNB) or Secondary eNB (SeNB) to perform certain actions, e.g. to establish, modify or release a Secondary Cell Group (SCG). The message may include additional information, e.g. to assist the SgNB or SeNB to set the SCG configuration. In the case of Central Unit (CU)/Distributed Unit (DU) split, it can also be used by a CU to request a DU to perform certain actions, e.g. to establish or modify a Master Cell Group (MCG) or SCG.
Systems and methods are disclosed herein that relate to inter-Secondary Node (SN) conditional cell change and measurement configuration. In one embodiment, a method for configuring measurements related to inter-SN conditional reconfiguration comprises, at a Source Secondary Node (S-SN), sending, to a Master Node (MN), a first message comprising an indication that the first message is for conditional reconfiguration and information about one or more target candidate cells of a target candidate SN. The method further comprises, at the MN, receiving the first message from the S-SN and sending a second message to the target candidate SN, the second message being a request for SN addition and comprising an indication that the second message is for conditional reconfiguration and information about the one or more target candidate cells of the target candidate SN. In this manner, the network is enabled to use the information about the target candidate cells, and ultimately information about select target candidate cells, to enable measurement configuration for conditional reconfiguration at a User Equipment (UE) in a manner in which there is low risk for configuration mismatch between the UE and the network and energy is not wasted at the UE by performing unnecessary measurements.
In on embodiment, the first message comprises a Secondary Cell Group (SCG) measurement configuration for conditional reconfiguration. In one embodiment, the method further comprises, at the target candidate SN, receiving the second message from the MN and sending a third message to the MN, the third message comprising information about one or more select target candidate cells from among the one or more target candidate cells of the target candidate SN. The method further comprises, at the MN, receiving the third message from the target candidate SN and determining whether there is a need for a second procedure for updating the SCG measurement configuration based on the information comprised in the third message. In one embodiment, the method further comprises, at the MN, responsive to determining there is not a need for the second procedure for updating the SCG measurement configuration, sending a fourth message to a UE, the fourth message comprising the SCG measurement configuration for conditional reconfiguration. In another embodiment, responsive to determining there is a need for the second procedure for updating the SCG measurement configuration, communicating with the S-SN to perform the second procedure for updating the SCG measurement configuration to thereby obtain an updated SCG measurement configuration and sending a fourth message to a UE, the fourth message comprising the updated SCG measurement configuration for conditional reconfiguration.
In another embodiment, the method further comprises, at the target candidate SN, receiving the second message from the MN and sending a third message to the MN, the third message comprising information about one or more select target candidate cells from among the one or more target candidate cells of the target candidate SN. The method further comprises, at the MN, receiving the third message from the target candidate SN and sending a fourth message to the S-SN, the fourth message comprising the information about one or more select target candidate cells. The method further comprises, at the S-SN, receiving the fourth message from the MN and sending, based on the information about the one or more select target candidate cells, a fifth message to the MN, the fifth message comprising measurement configuration information related to the conditional reconfiguration. The method further comprises, at the MN, receiving the fifth message from the S-SN and sending a sixth message to a UE, the sixth message comprising the measurement configuration information related to the conditional reconfiguration. In this manner, configuration is provided with low risk for configuration mismatch between the UE and the network.
In one embodiment, the method further comprises, at the UE, receiving the sixth message from the MN.
In one embodiment, the first message is a SN Change Required message.
In one embodiment, the first message comprises a CG-Config Information Element (IE) that comprises the information about the one or more target candidate cells of the target candidate SN.
In one embodiment, the information about the one or more target candidate cells of the target candidate SN comprises an Absolute Radio Frequency Channel Number (AFCN) and a physical cell identity (ID) for each of the one or more target candidate cells of the target candidate SN.
In one embodiment, the second message is an SN Addition Request.
In one embodiment, the third message is an SN Additional Request acknowledgement.
In one embodiment, the information about the one or more select target candidate cells comprises an AFCN and a physical cell ID for each of the one or more select target candidate cells.
In one embodiment, the fourth message is an SN Change Confirm.
In one embodiment, the fifth message is an SN Modification Required message.
In one embodiment, the measurement configuration information related to the conditional reconfiguration comprises one or more measurement IDs associated to one or more respective execution conditions for the one or more select target candidate cells.
In one embodiment, the fifth message further comprises information related to measurement gaps that enables the S-SN to determine measurement gaps the UE needs to be configured with to perform inter-frequency measurements on frequencies associated to the one or more select target candidate cells.
In one embodiment, the sixth message is a Radio Resource Control (RRC) Reconfiguration message.
Embodiments of a method performed by a S-SN are also disclosed. In one embodiment, a method performed by a S-SN for configuring measurements related to inter-SN conditional reconfiguration comprises sending, to a MN, a first message comprising an indication that the first message is for conditional reconfiguration and information about one or more target candidate cells of a target candidate SN. The method further comprises receiving a second message from the MN comprising information about one or more select target candidate cells from among the one or more target candidate cells of the target candidate SN and sending, based on the information about the one or more select target candidate cells, a third message to the UE, where the measurement configuration information is related to the conditional reconfiguration.
In one embodiment, the first message is a SN Change Required message.
In one embodiment, the first message comprises a CG-Config IE that comprises the information about the one or more target candidate cells of the target candidate SN.
In one embodiment, the information about the one or more target candidate cells of the target candidate SN comprises an AFCN and a physical cell ID for each of the one or more target candidate cells of the target candidate SN.
In one embodiment, the information about the one or more select target candidate cells comprises an AFCN and a physical cell ID for each of the one or more select target candidate cells.
In one embodiment, the second message is an SN Change Confirm.
In one embodiment, the third message is an SN Modification Required message.
In one embodiment, the measurement configuration information related to the conditional reconfiguration comprises one or more measurement IDs associated to one or more respective execution conditions for the one or more select target candidate cells.
In one embodiment, the third message further comprises information related to measurement gaps that enables the S-SN to determine measurement gaps the UE needs to be configured with to perform inter-frequency measurements on frequencies associated to the one or more select target candidate cells.
Corresponding embodiments of a S-SN are also disclosed. In one embodiment, a S-SN for configuring measurements related to inter-SN conditional reconfiguration is adapted to send, to a MN, a first message comprising an indication that the first message is for conditional reconfiguration and information about one or more target candidate cells of a target candidate SN. The S-SN is further adapted to receive a second message from the MN comprising information about one or more select target candidate cells from among the one or more target candidate cells of the target candidate SN and send, based on the information about the one or more select target candidate cells, a third message to the MN comprising measurement configuration information for a UE, where the measurement configuration information is related to the conditional reconfiguration.
In one embodiment, a S-SN for configuring measurements related to inter-SN conditional reconfiguration comprises processing circuitry configured to cause the S-SN to send, to a MN, a first message comprising an indication that the first message is for conditional reconfiguration and information about one or more target candidate cells of a target candidate SN. The processing circuitry is further configured to cause the S-SN to receive a second message from the MN comprising information about one or more select target candidate cells from among the one or more target candidate cells of the target candidate SN and send, based on the information about the one or more select target candidate cells, a third message to the MN comprising measurement configuration information for a UE, where the measurement configuration information is related to the conditional reconfiguration.
Embodiments of a method performed by a MN are also disclosed. In one embodiment, a method performed by a MN for configuring measurements related to inter-SN conditional reconfiguration comprises receiving a first message from a S-SN comprising an indication that the first message is for conditional reconfiguration and information about one or more target candidate cells of a target candidate SN and sending a second message to the target candidate SN, the second message being a request for SN addition and comprising an indication that the second message is for conditional reconfiguration and information about the one or more target candidate cells of the target candidate SN.
In one embodiment, the first message comprises a SCG measurement configuration for conditional reconfiguration. In one embodiment, the method further comprises receiving a third message from the target candidate SN, the third message comprising information about one or more select target candidate cells from among the one or more target candidate cells of the target candidate SN. The method further comprises determining whether there is a need for a second procedure for updating the SCG measurement configuration based on the information comprised in the third message. In one embodiment, the method further comprises, responsive to determining there is not a need for the second procedure for updating the SCG measurement configuration, sending a fourth message to a UE, the fourth message comprising the SCG measurement configuration for conditional reconfiguration. In another embodiment, responsive to determining there is a need for the second procedure for updating the SCG measurement configuration, communicating with the S-SN to perform the second procedure for updating the SCG measurement configuration to thereby obtain an updated SCG measurement configuration and sending a fourth message to a UE, the fourth message comprising the updated SCG measurement configuration for conditional reconfiguration.
In another embodiment, the method further comprises receiving a third message from the target candidate SN comprising information about one or more select target candidate cells from among the one or more target candidate cells of the target candidate SN, sending a fourth message to the S-SN comprising the information about one or more select target candidate cells, receiving a fifth message from the S-SN comprising measurement configuration information related to the conditional reconfiguration, and sending a sixth message to a UE, the sixth message comprising the measurement configuration information related to the conditional reconfiguration.
In one embodiment, the first message is a SN Change Required message.
In one embodiment, the first message comprises a CG-Config IE that comprises the information about the one or more target candidate cells of the target candidate SN.
In one embodiment, the information about the one or more target candidate cells of the target candidate SN comprises an AFCN and a physical cell ID for each of the one or more target candidate cells of the target candidate SN.
In one embodiment, the second message is an SN Addition Request.
In one embodiment, the third message is an SN Additional Request acknowledgement.
In one embodiment, the information about the one or more select target candidate cells comprises an AFCN and a physical cell ID for each of the one or more select target candidate cells.
In one embodiment, the fourth message is an SN Change Confirm.
In one embodiment, the fifth message is an SN Modification Required message.
In one embodiment, the measurement configuration information related to the conditional reconfiguration comprises one or more measurement IDs associated to one or more respective execution conditions for the one or more select target candidate cells.
In one embodiment, the fifth message further comprises information related to measurement gaps that enables the S-SN to determine measurement gaps the UE needs to be configured with to perform inter-frequency measurements on frequencies associated to the one or more select target candidate cells.
In one embodiment, the sixth message is an RRC Reconfiguration message.
Corresponding embodiments of a MN are also disclosed. In one embodiment, a MN for configuring measurements related to inter-SN conditional reconfiguration is adapted to receive a first message from a S-SN comprising an indication that the first message is for conditional reconfiguration and information about one or more target candidate cells of a target candidate SN and send a second message to the target candidate SN, the second message being a request for SN addition and comprising an indication that the second message is for conditional reconfiguration and information about the one or more target candidate cells of the target candidate SN.
In one embodiment, a MN for configuring measurements related to inter-SN conditional reconfiguration comprises processing circuitry configured to cause the MN to receive a first message from a S-SN comprising an indication that the first message is for conditional reconfiguration and information about one or more target candidate cells of a target candidate SN and send a second message to the target candidate SN, the second message being a request for SN addition and comprising an indication that the second message is for conditional reconfiguration and information about the one or more target candidate cells of the target candidate SN.
Embodiments of a method performed by a target candidate SN are also disclosed. In one embodiment, a method performed by a target candidate SN for configuring measurements related to inter-SN conditional reconfiguration comprises receiving a first message from a MN, the first message being a request for SN addition and comprising an indication that the second message is for conditional reconfiguration and information about the one or more target candidate cells of the target candidate SN. The method further comprises sending a second message to the MN comprising information about one or more select target candidate cells from among the one or more target candidate cells of the target candidate SN.
In one embodiment, the information about the one or more target candidate cells of the target candidate SN comprises an AFCN and a physical cell ID for each of the one or more target candidate cells of the target candidate SN.
In one embodiment, the first message is an SN Addition Request.
In one embodiment, the second message is an SN Additional Request acknowledgement.
In one embodiment, the information about the one or more select target candidate cells comprises an AFCN and a physical cell ID for each of the one or more select target candidate cells.
Corresponding embodiment of a target candidate SN are also disclosed. In one embodiment, a target candidate SN for configuring measurements related to inter-SN conditional reconfiguration is adapted to receive a first message from a MN, the first message being a request for SN addition and comprising an indication that the second message is for conditional reconfiguration and information about the one or more target candidate cells of the target candidate SN. The target candidate SN is further adapted to send a second message to the MN comprising information about one or more select target candidate cells from among the one or more target candidate cells of the target candidate SN.
In one embodiment, a target candidate SN for configuring measurements related to inter-SN conditional reconfiguration comprises processing circuitry configured to cause the target candidate SN to receive a first message from a MN, the first message being a request for SN addition and comprising an indication that the second message is for conditional reconfiguration and information about the one or more target candidate cells of the target candidate SN. The processing circuitry is further configured to cause the target candidate SN to send a second message to the MN comprising information about one or more select target candidate cells from among the one or more target candidate cells of the target candidate SN.
The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure.
The embodiments set forth below represent information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure.
Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein, the disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.
Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and/or is implied from the context in which it is used. All references to a/an/the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and/or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features, and advantages of the enclosed embodiments will be apparent from the following description.
Radio Node: As used herein, a “radio node” is either a radio access node or a wireless communication device.
Radio Access Node: As used herein, a “radio access node” or “radio network node” or “radio access network node” is any node in a Radio Access Network (RAN) of a cellular communications network that operates to wirelessly transmit and/or receive signals. Some examples of a radio access node include, but are not limited to, a base station (e.g., a New Radio (NR) base station (gNB) in a Third Generation Partnership Project (3GPP) Fifth Generation (5G) NR network or an enhanced or evolved Node B (eNB) in a 3GPP Long Term Evolution (LTE) network), a high-power or macro base station, a low-power base station (e.g., a micro base station, a pico base station, a home eNB, or the like), a relay node, a network node that implements part of the functionality of a base station (e.g., a network node that implements a gNB Central Unit (gNB-CU) or a network node that implements a gNB Distributed Unit (gNB-DU)) or a network node that implements part of the functionality of some other type of radio access node.
Core Network Node: As used herein, a “core network node” is any type of node in a core network or any node that implements a core network function. Some examples of a core network node include, e.g., a Mobility Management Entity (MME), a Packet Data Network Gateway (P-GW), a Service Capability Exposure Function (SCEF), a Home Subscriber Server (HSS), or the like. Some other examples of a core network node include a node implementing an Access and Mobility Management Function (AMF), a User Plane Function (UPF), a Session Management Function (SMF), an Authentication Server Function (AUSF), a Network Slice Selection Function (NSSF), a Network Exposure Function (NEF), a Network Function (NF) Repository Function (NRF), a Policy Control Function (PCF), a Unified Data Management (UDM), or the like.
Communication Device: As used herein, a “communication device” is any type of device that has access to an access network. Some examples of a communication device include, but are not limited to: mobile phone, smart phone, sensor device, meter, vehicle, household appliance, medical appliance, media player, camera, or any type of consumer electronic, for instance, but not limited to, a television, radio, lighting arrangement, tablet computer, laptop, or Personal Computer (PC). The communication device may be a portable, hand-held, computer-comprised, or vehicle-mounted mobile device, enabled to communicate voice and/or data via a wireless or wireline connection.
Wireless Communication Device: One type of communication device is a wireless communication device, which may be any type of wireless device that has access to (i.e., is served by) a wireless network (e.g., a cellular network). Some examples of a wireless communication device include, but are not limited to: a User Equipment device (UE) in a 3GPP network, a Machine Type Communication (MTC) device, and an Internet of Things (IoT) device. Such wireless communication devices may be, or may be integrated into, a mobile phone, smart phone, sensor device, meter, vehicle, household appliance, medical appliance, media player, camera, or any type of consumer electronic, for instance, but not limited to, a television, radio, lighting arrangement, tablet computer, laptop, or PC. The wireless communication device may be a portable, hand-held, computer-comprised, or vehicle-mounted mobile device, enabled to communicate voice and/or data via a wireless connection.
Network Node: As used herein, a “network node” is any node that is either part of the RAN or the core network of a cellular communications network/system.
Transmission/Reception Point (TRP): In some embodiments, a TRP may be either a network node, a radio head, a spatial relation, or a Transmission Configuration Indicator (TCI) state. A TRP may be represented by a spatial relation or a TCI state in some embodiments. In some embodiments, a TRP may be using multiple TCI states. In some embodiments, a TRP may a part of the gNB transmitting and receiving radio signals to/from UE according to physical layer properties and parameters inherent to that element. In some embodiments, in Multiple TRP (multi-TRP) operation, a serving cell can schedule UE from two TRPs, providing better Physical Downlink Shared Channel (PDSCH) coverage, reliability and/or data rates. There are two different operation modes for multi-TRP: single Downlink Control Information (DCI) and multi-DCI. For both modes, control of uplink and downlink operation is done by both physical layer and Medium Access Control (MAC). In single-DCI mode, UE is scheduled by the same DCI for both TRPs and in multi-DCI mode, UE is scheduled by independent DCIs from each TRP.
Note that the description given herein focuses on a 3GPP cellular communications system and, as such, 3GPP terminology or terminology similar to 3GPP terminology is oftentimes used. However, the concepts disclosed herein are not limited to a 3GPP system.
Note that, in the description herein, reference may be made to the term “cell”; however, particularly with respect to 5G NR concepts, beams may be used instead of cells and, as such, it is important to note that the concepts described herein are equally applicable to both cells and beams.
There currently exist certain challenge(s). In a recent paper by Ericsson to RAN2 #113e (R2-2101270) and RAN2 #114e (R2-2105898), solutions related to how the UE performs Conditional Primary Secondary Cell (PSCell) Change (CPC) related measurements in the case of inter-Secondary Node (SN) CPC was proposed.
In addition, the solution described in R2-2105898 comprises the Source SN (S-SN) generating an SCG Reconfiguration (also called SN Reconfiguration, as it is in SN format) containing an SCG Measurement Configuration (SCG MeasConfig) comprising the CPC related measConfig, i.e. the configuration of measurement identifiers and association to measurement object(s) and reporting configuration(s) for conditional reconfiguration (e.g., CPC). It has also been proposed that the S-SN includes that in the SN Change Required message to the MN, with some indication this is conditional, e.g. for CPC; with information about target candidate cells (PSCell candidates), such as measurements, and Target candidate SN(s) (T-SN).
The solution in R2-2105898 is applicable for the following case: the S-SN includes a request for a number (e.g., N) of target cell candidates associated to measId(s) and the SCG MeasConfig for CPC, the MN requests the target candidate SN to prepare the RRCReconfiguration** for CPC for each target cell candidate, and the T-SN prepared the RRCReconfiguration** for all N request candidates.
The solution in R2-2105898 is also applicable for some cases where the target SN does not accept all the N candidates, i.e., it accepts a subset (K target candidates, with K<N) of candidates and prepares a subset of RRCReconfiguration**, per each of the K candidates. One of the cases is if the measId(s) configured in the SCG MeasConfig are set per frequency (i.e., for target candidates in the same frequency, the same measId(s) is used) and, if all the requested frequencies are represented by at least one candidate, the SCG MeasConfig from S-SN in SN Change Required (i.e., in RRCReconfiguration***) is still applicable.
Example 1) For example, let's say that the S-SN indicates the following in the SN Change Required (e.g., in the CG-Config container) to the MN, when requesting an inter-SN CPC to the MN:
Frequency A
Frequency B
RRCReconfiguration***
A possible limitation of the solution in R2-2105898 may exist in scenarios where at least one MeasID of the execution condition for CPC is configured by the S-SN for a frequency whose target candidate PSCell has not been accepted by the target candidate SN (in SN Addition Request with conditional indication) and/or at least one MeasID is configured by the S-SN for a PSCell that has not been accepted by the target candidate SN (in SN Addition Request with conditional indication). In that case, the UE would receive an SCG measConfig including the CPC related measConfig that contains a configured measId that may not be associated to a target candidate PSCell, i.e. the measurement would not be necessary. That could lead to unnecessary measurements being performed, which leads to unnecessary power consumption, and/or at least the UE having a configuration that is not used for anything.
Example 2) For example, let's say again that the S-SN indicates the following in the SN Change Required (e.g., in the CG-Config container) to the MN, when request an inter-SN CPC to the MN:
Frequency A
Frequency B
RRCReconfiguration***
Certain aspects of the present disclosure and their embodiments may provide solutions to the aforementioned or other challenges. Systems and methods for inter-SN conditional cell change and measurement configuration are provided. Embodiments provide for inter-SN CPC and SCG MeasConfig. There may be different solutions to address the problems described above, organized in a set of embodiments. Each solution is organized in steps, wherein steps of one solution may be combined with steps of another solution. These solutions include:
There are, proposed herein, various embodiments which address one or more of the issues disclosed herein. In some embodiments, a method is performed by a UE for configuring a CPC, the method comprising one or more of: receiving a RRC configuration message that includes a CPC configuration; and applying the CPC configuration.
In some embodiments, a UE is configured to communicate with a network node, the UE comprising processing circuitry configured to perform the method of any of the above embodiments.
In some embodiments, a method is performed by a radio access node for configuring a CPC the method comprising one or more of: sending a message to a MN indicating a SN change is required; receiving a SN change confirm message including information regarding a target candidate SN; and triggering a second procedure for updating a SCG measurement configuration.
In some embodiments, a method is performed by a radio access node for configuring a CPC, the method comprising one or more of: receiving a message indicating a SN change is required; sending a SN addition request to a target candidate SN; receiving a SN addition response from the target candidate SN; and determining if there is a need for a second procedure for updating a SCG measurement configuration.
In some embodiments, a method is performed by a radio access node for configuring a CPC, the method comprising one or more of: receiving a message indicating a SN change is required; sending a SN addition request to a target candidate SN; receiving a SN addition response from the target candidate SN; and determining which version of a SCG measurement configuration is selected.
In some embodiments, a method is performed by a radio access node for configuring a Conditional Primary Secondary Cell, PSCell, Change, CPC, the method comprising one or more of: receiving a message indicating a SN change is required; sending a SN addition request to a target candidate SN; receiving a SN addition response from the target candidate SN; and determining execution conditions to be provided to a UE.
In some embodiments, a radio access node is configured to communicate with a UE, the network node comprising processing circuitry configured to perform the method of any of the above embodiments.
Certain embodiments may provide one or more of the following technical advantage(s). The different solutions have different advantages which can be summarized as follows:
The base stations 502 and the low power nodes 506 provide service to wireless communication devices 512-1 through 512-5 in the corresponding cells 504 and 508. The wireless communication devices 512-1 through 512-5 are generally referred to herein collectively as wireless communication devices 512 and individually as wireless communication device 512. In the following description, the wireless communication devices 512 are oftentimes UEs and as such sometimes referred to herein as UEs 512, but the present disclosure is not limited thereto.
The present disclosure refers to a first network node operating as a MN, e.g. having a MCG configured to the UE and/or an MN-terminated bearer; that MN can be a gNB, or a Central Unit gNB (CU-gNB) or an eNB, or a Central Unit eNB (CU-gNB), or any network node and/or network function. The present disclosure also refers to a second network node operating as a SN, or S-SN e.g. having a SCG connected to the UE; that SN can be a gNB, or a CU-gNB) or an eNB, or a CU-gNB, or any network node and/or network function. Notice that MN, S-SN, and T-SN may be from the same or different Radio Access Technologies and possibly be associated to different Core Network nodes.
The present disclosure refers to a target SN (T-SN) candidate, target candidate SN, or SN candidate, or an SN, or T-SN, as the network node (e.g. gNB) that is prepared during the CPC configuration procedure and that can create an RRC Reconfiguration message with an SCG configuration (e.g. RRCReconfiguration**) to be provided to the UE and stored, with an execution condition, wherein the UE only applies the message upon the fulfillment of the execution condition. That target candidate SN, denoted most of the time in the document as T-SN, is associated to one or multiple PSCell candidate cell(s) that the UE can be configured with. The UE then can execute the condition and accesses one of these candidate cells, associated to a candidate SN that becomes the SN or simply the SN after execution (i.e., upon fulfillment of the execution condition).
The present disclosure refers most of the time to one T-SN. However, the methods include the possibility that the S-SN requests to the MN for CPC target candidate cells/frequencies from one or more T-SN. Consequently, the MN may send SN Addition Requests to one or more T-SN. Hence, any operation the MN needs to perform based on input from the T-SN, may need to wait the response (e.g., SN Addition Request Ack) from all requested T-SN candidates.
The present disclosure refers to a CPC configuration and procedures (like CPC execution), most of the time to refer to the procedure from the UE perspective. Other terms may be considered as synonyms such as conditional reconfiguration, or Conditional Configuration (since the message that is stored and applied upon fulfillment of a condition is an RRCReconfiguration or RRCConnectionReconfiguration). Terminology wise, one could also interpret conditional handover (CHO) in a broader sense, also covering CPA (Conditional PSCell Change) procedures. The present disclosure refers to a Conditional SN Change most of the time to refer to the procedure from the UE perspective, to refer to procedures between network nodes wherein a node requests a target candidate SN (which may be the same as the Source SN or a neighbor SN) to configure a conditional PSCell Change (CPC) for at least one of its associated cells (cell associated to the target candidate SN).
The present disclosure refers to CPAC as a way to refer to either a Conditional PSCell Addition (CPA) or a Conditional PSCell Change (CPC).
The configuration of CPC refers to a conditional configuration or conditional reconfiguration. The principle for the configuration is the same with configuring triggering/execution condition(s) and a reconfiguration message to be applied when the triggering condition(s) are fulfilled. When the present disclosure refers to a CPC configuration it may refer to any of the Information Elements (IEs) indicated below (as defined in TS 38.331) or field associated to the IEs:
ConditionalReconfiguration
The IE ConditionalReconfiguration is used to add, modify, and release the configuration of conditional configuration.
CondConfigId
The IE CondConfigId is used to identify a CHO or CPC configuration.
CondConfigToAddModList
The IE CHO-ConfigToAddModList concerns a list of conditional configurations to add or modify, with for each entry the cho-ConfigId and the associated condExecutionCond and condRRCReconfig.
In the different embodiments of the solutions disclosed herein, these IEs are used differently, and, in the case of inter-SN CPC, it is assumed they are generated by the MN. That does not preclude parts of the IE being based on input provided by the S-SN (e.g., execution conditions and SCG MeasConfig for CPC, configuring the execution conditions measId(s)), or the T-SN candidate (e.g., the target candidate configurations, denoted RRCReconfiguration** per PSCell candidate). That comprises the MN generating the IE CondReconfigToAddMod for each target candidate cell.
In the different embodiments of the solutions disclosed herein, it is said the CPC is in MN format when the CPC configuration is not configured as an MR-DC configuration in mrdc-SecondaryCellGroup (as defined in TS 38.331). In other words, the UE receives an RRCReconfiguration from the MN that may contain the mrdc-SecondaryCellGroup (e.g., in case the UE is also configured with an SCG MeasConfig for inter-SN CPC) but the CPC is not within that container. That means the IEs listed above (e.g., the IE ConditionalReconfiguration) are not included in mrdc-SecondaryCellGroup.
In the present disclosure, the terms SCG MeasConfig for CPC, SCG MeasConfig, CPC related measurement configuration, are used interchangeably. It refers to the fact that the MeasConfig IE including the configuration of the MeasID(s) that are referred by the CPC execution conditions (i.e., in condExecutionCond in the IE CondConfigToAddMod).
The SCG MeasConfig for CPC comprises at least one of the following:
Embodiments of the solutions described herein may comprise that the SCG MeasConfig for CPC also includes measurement gap configurations for the UE, determined by a measurement gap coordination between the MN and the S-SN (e.g., determined by the S-SN that also determines the frequencies to be measured for CPC and the conditions). That comprises at least one of the parameters in the IE below.
Solution 1: Additional Procedure for Configuring SCG measConfig for CPC
Step 1108: In one set of embodiments, the S-SN 1100 transmits a message to the MN 1102 (e.g., SN Change Required) including an indication this is for a Conditional Reconfiguration (e.g., CPC) and including information of target candidate cells of at least one target candidate SN (e.g., N target candidate PSCell, including measurement results for at least one PSCell candidate), possibly in different frequency (e.g., having different SSB frequency/ARFCN for the SSB).
This message can be defined as follows:
This message is sent by the S-NG-RAN node to the M-NG-RAN node to trigger the change of the S-NG-RAN node.
Direction: S-NG-RAN node→M-NG-RAN node.
Step 1110: Upon reception of the message, the MN 1102 determines this is for CPC (e.g. based on some indication in the SN Change Required, like a cause value, the configuration of the execution conditions, etc.), and the MN 1102 sends an SN Addition Request to the T-SN 1104 (i.e., to the target candidate SN(s)) indicated in the message (e.g. Target S-NG-RAN node ID(s) of type Global NG-RAN Node ID), including an indication this is for a conditional procedure (e.g. CPC, or a procedure to be executed only upon fulfillment of an execution condition) and including the information of the candidate PSCells/frequencies from the S-SN e.g. including the CG-Config inter-node RRC container (that include measurement results).
The T-SN 1104 receives the SN Addition Request for CPC and selects a set of candidate cells out of the candidate cells provided in the SN Addition Request (e.g., within CG-Config, as described above).
Step 1112: After the selection, the T-SN candidate (i.e., the T-SN 1104) sends a message to the MN 1102 (e.g., SN Addition Request Ack) including the information of the selected candidate cells to the MN 1102, including for each selected candidate an RRC Reconfiguration to be applied upon the fulfillment of the execution condition, denoted RRCReconfiguration** (this is the SCG configuration to be provided to the UE 1106 as part of the MN-generated CPC configuration).
In one option, the SN Addition Request Ack includes further information on the selected cell candidates that can be interpreted by the MN 1102, as the MN 1102 needs to take further actions based on the selection from the T-SN 1104. That information can be, for example, a list of physical cell identity+frequency information. There are different possible ways to encode this information in the SN Addition Request Ack message, such as:
This message is sent by the S-NG-RAN node to confirm the M-NG-RAN node about the S-NG-RAN node addition preparation.
Direction: S-NG-RAN→node M-NG-RAN node.
This message is sent by the S-NG-RAN node to confirm the M-NG-RAN node about the S-NG-RAN node addition preparation.
Direction: S-NG-RAN→node M-NG-RAN node.
Upon reception, the MN 1102, in one option, does not need to determine whether the target candidate cells indicated by the S-SN 1100 and/or the target candidate frequencies have been selected by the T-SN 1104 candidate.
Step 1114: Upon reception of the message from the T-SN 1104 candidate (e.g., the SN Addition Request Ack as in Step 1112), the MN 1102 sends to the S-SN 1100 a message including the information from the T-SN 1104 concerning the selected target candidates, as indicated by the T-SN 1104. The message from the MN 1102 to the S-SN 1100 may be, for example, an SN Change Confirm. The information on the selected target candidate cells may be contained in an inter-node RRC message/RRC container (e.g., CG-Config container) as received from the T-SN 1104 or included as an XnAP information. The S-SN 1100 does not require to receive the RRCReconfiguration** prepared by the T-SN 1104 per target candidate cell, but only which cells and/or frequencies have been selected to enable the S-SN 1100 to generate the CPC related measurement configuration.
Step 116: The S-SN 1100, upon receiving from the MN 1102 the information about the target cell candidates selected by the T-SN 1104 (via the MN 1102, e.g. in the SN Change Confirm), determines which candidate cells have been selected and generates the CPC related measurement configuration to be provided to the UE 1106, and associated to the execution condition(s) for a given frequency and/or target cell candidate. The CPC related measurement configuration can be an SCG MeasConfig encoded in a container and denoted an RRCReconfiguration***. That includes the configuration of the measId(s) associated to the execution condition(s) only for the target candidate cells selected by the T-SN 1104, as indicated by the MN 1102.
That message from the MN 1102 to the S-SN 1100 may also include information related to measurement gaps, i.e., information enabling the S-SN 1100 to determine the measurement gaps the UE 1106 needs to be configured with to perform inter-frequency measurements on the frequencies associated to the target candidate cells, i.e., as selected by the T-SN candidate(s). That may comprise, for example, the current measurement gaps the UE 1106 is configured with, e.g., by the MN 1102 and/or as an MCG measConfig, and/or current frequencies the MN 1102 has configured the UE 1106 to measure. The information may be any of the fields included in the inter-node RRC IE CG-ConfigInfo. An example is shown below:
This message is used by master eNB or gNB to request the SgNB or SeNB to perform certain actions, e.g. to establish, modify or release an SCG. The message may include additional information, e.g. to assist the SgNB or SeNB to set the SCG configuration. It can also be used by a CU to request a DU to perform certain actions, e.g. to establish or modify an MCG or SCG. It may be included in the SN Change Confirm in the case of CPC.
Direction: Master eNB or gNB to secondary gNB or eNB, alternatively CU to DU.
In one example, the container CG-ConfigInfo (that includes MN information about measurement gaps) is included in the SN Change Confirm from the MN to the S-SN. That is for the case the SN Change Confirm is used for confirming CPC configuration to the S-SN. That example is shown below as it would modify TS 38.423:
This message is sent by the M-NG-RAN node to inform the S-NG-RAN node that the preparation of the S-NG-RAN node initiated S-NG-RAN node change was successful.
Direction: M-NG-RAN→node S-NG-RAN node.
Step 1118: The S-SN 1100, after having generated the CPC related measurement configuration (SCG MeasConfig, denoted RRCReconfiguration***), to be applied upon CPC configuration by the UE 1106, sends that to the MN 1102 in a message, e.g. an SN Modification Required (as that is a message modifying the UE's SCG configuration, as the measId(s) are configured within an SCG MeasConfig). The S-SN 1100 may also configure measurement reporting in that SCG measConfig in RRCReconfiguration***, in addition to the CPC related measurement configuration. This can be interpreted as what is referred to herein as the second procedure, in addition to the SN Change procedure. The S-SN 1100 may also configure measurement gaps, depending on the UE's current gap configuration (as indicate by the MN 1102, possibly in the SN Change Required, or previously known by the S-SN 1100), the UE capabilities, and the selected target candidate frequencies by the S-SN 1100.
In one example, the SCG measConfig, within the denoted RRCReconfiguration*** is included in the S-NG-RAN node to M-NG-RAN node Container, that includes the CG-Config message as defined in subclause 11.2.2 of 3GPP TS 38.331. So, the field scg-CellGroupConfig is set to the RRCReconfiguration***, as shown in
In one sub-option, in addition to the SCG MeasConfig, configuring the measId(s), the S-SN 1100 may provide in the same message the execution conditions associated to the candidate cell(s), e.g. to the selected target candidate cell(s). That makes sense in the case there is an additional procedure for configuring CPC measConfig, i.e. there is a (conditional) Secondary Node Change (for the MN to obtain the T-SN target candidate cell configurations) followed by a Secondary Node Modification (for the MN to obtain the SCG MeasConfig for CPC, and in this sub-option the configuration for the execution conditions per target candidate frequency/cell). Details on how the execution conditions can be encoded and provided from the S-SN to the MN are provided further below (entitled Further details about the Execution condition(s) per target candidate frequency/cell).
Upon reception of the message from the S-SN 1100 (e.g., SN Modification Required), the MN 1102 generates CPC in MN format. The MN 1102 first generates the main MN message (RRCReconfiguration) to be applied by the UE 1106 upon reception, including the Information Element (IE) ConditionalReconfiguration and the CondReconfigToAddModList, as shown in
Then, the MN 1102 needs to generate the CondReconfigToAddMod for each target candidate cell. There can be different options, depending on whether the execution condition is transparent to the MN 1102 or not. In the first sub-option, shown in
In a second sub-option, the execution condition set by the S-SN 1100 is not transparent to the MN 1102, and in that case, there is no need of a new field/IE in CondReconfigToAddMod. Instead, the MN 1102 sets the condExecutionCond-r16 to the one or two (or more) integers indicated by the S-SN 1100 as the execution conditions for the corresponding candidate frequency and/or cell.
Then, within each condRRCReconfig for a given target candidate, the MN 1102 generates an RRCReconfiguration in MN format (denoted RRCReconfiguration*) including as its SCG configuration the RRCReconfiguration** for each selected target candidate cell, as provided by the T-SN.
Step 1120: The MN 1102 provides the RRCReconfiguration message (in MN format, and generated by the MN 1102) including the CPC configuration (i.e., the condReconfigToAddModList-r16 or IE CondReconfigToAddModList-r16) to the UE 1106.
Step 1122: The UE 1106 sends an RRCReconfigurationComplete to the MN 1102.
Step 1124: The MN 1102 sends a SN Modification Confirm to the S-SN 1100.
After receiving the RRCReconfiguration in step 1120, the UE 1106 applies the CPC configuration and starts to monitor the fulfillment of the execution conditions that have been configured.
In one embodiment, the UE 1106 receives for a given candidate target cell for CPC the IE CondReconfigToAddMod. If that includes a first field for an execution condition, this indicates that the measID(s) associated are configured in the MCG MeasConfig. For example, that is the case, for example, if condExecutionCond-r16 of IE SEQUENCE (SIZE (1..2)) OF MeasId is included. Else, if that includes a second field for an execution condition, this indicates that the measID(s) associated are configured in the SCG MeasConfig. For example, that is the case, for example, if condExecutionCond2-r17 of IE OCTET STRING (CONTAINING CondReconfigExecCond-r17), defined as the IE SEQUENCE (SIZE (1..2)) OF MeasId is included.
In another variant of Solution 1, the T-SN 1104 needs to configure measurement gaps without considering delta signaling, i.e. the T-SN 1104 needs to release whatever measurement gap the UE 1106 has configured and configures a new measurement gap configuration. The reason is that the T-SN 1104 may not know the exact gap configuration the UE 1106 has, as that may be updated in the second procedure, according to Solution 1. Hence, this is some kind of full config at least for the perspective of measurement gaps.
Solution 2; Opportunistic Provision of SCG measConfig for CPC
In the following, different steps of the procedures of
Step 1708/1808: In one set of embodiments, the S-SN 1700/1800 transmits a message to the MN 1702/1802 (e.g. SN Change Required) including an indication that the message is for a Conditional Reconfiguration (e.g. CPC) and including information of target candidate cells of at least one target candidate SN (e.g. N target candidate PSCells, including measurement results for at least one PSCell candidate), possibly in different frequency (e.g. having different SSB frequency/ARFCN for the SSB). In this example, the at least one target candidate SN includes the T-SN 1704/1804. The various ways that information can be included can be as described in Solution 1, e.g., in CG-Config container.
In addition, the message opportunistically includes the execution conditions (i.e., the measId(s) associated to the target candidate cells and/or frequencies) and/or the SCG measConfig for CPC (that may include a measurement gap configuration according to the selected frequencies). There are different ways to include the execution conditions in the message from the S-SN 1700/1800 to the MN 1702/1802, as described further below. Upon reception, the MN 1702/1802 stores the SCG MeasConfig for CPC and/or the execution conditions (and association to target cell and/or frequency candidates).
In the case the S-SN 1700/1800 includes a measurement gap configuration in the SCG MeasConfig for CPC, opportunistically, the S-SN 1700/1800 may also indicate gap related information to the MN 1702/1802.
Another alternative is to define the inclusion of the SCG measConfig for CPC and/or the execution conditions per cell/frequency candidates in the message from the S-SN 1700/1800 to the MN 1702/1802 (e.g., in the SN Change Required) as optional. If that is included, the S-SN 1700/1800 wants to indicate that the opportunistic approach can be used by the MN 1702/1802, i.e., that the MN 1702/1802 can apply at least one of the rules defined in step 1716/1818, and possibly skip the second procedure. If that is not included in the message, the MN 1702/1802 is aware that is needs to act as defined with respect to Solution 1 (i.e., it always waits for a second procedure triggered by the S-SN 1700/1702).
Step 1710/1810: The MN 1702/1802 stores the SCG measConfig.
Step 1712/1812: This is similar to Step 1110 in Solution 1.
Step 1714/1814: After the selection, the (candidate) T-SN 1704/1804 sends a message to the MN 1702/1802 (e.g. SN Addition Request Ack) including the information of the selected candidate cells, including for each selected candidate an RRC Reconfiguration to be applied upon the fulfillment of the execution condition, denoted RRCReconfiguration** (this is the SCG configuration to be provided to the UE 1706/1806 as part of the MN generated CPC configuration).
The T-SN 1704/1804, in the SN Addition Request Ack, includes further information on the selected cell candidates and/or frequencies. That information can be, for example, a list of cell identity (e.g., physical cell identity, global cell identity)+frequency information. There are different possible ways to encode this information in the SN Addition Request Ack message, as described in Step 1112 with respect to Solution 1, e.g., using a single CG-Config container. Even if the T-SN 1704/1804 has selected multiple target candidate cells, a single container may be used but within the container there are multiple RRC Reconfiguration messages (denoted RRCReconfiguration(s)**) to be applied by the UE 1706/1806 upon fulfillment of the execution condition, where there is at least one RRC Reconfiguration message per target candidate cell that has been selected.
Step 1716/1818: In one option, the further information on the selected cell candidates and/or frequencies can be interpreted by the MN 1702/1802 (e.g., is included in text format understandable by the MN 1702/1802, e.g., in XnAP). Based on that, the MN 1702/1802 determines whether a second procedure will be needed or whether the MN 1702/1802 can generate and send to the UE 1706/1806 the RRCReconfiguration including the CPC configuration (in MN format), including the stored provided SCG measConfig for CPC (and the execution conditions mapped to the target candidate cells/frequencies) provided by the S-SN 1700/1800 (e.g., in the SN Change Required).
The determination by the MN 1702/1802 is based on the further information on the selected cell candidates and/or frequencies.
As described above, the way the MN 1702/1802 determines whether it should configure the UE 1706/1806 with the stored SCG meaConfig for CPC or wait for a second procedure triggered by the S-SN 1700/1800 with an updated SCG MeasConfig is based on the understanding concerning the execution condition configuration, e.g. whether they are defined per frequency and/or per cell candidate. There can be sub-options for this determination:
Steps 1718, 1720, and 1722:
Steps 1816, 1820, 1822, 1824, 1826, and 1828:
In another option, the further information on the selected cell candidates and/or frequencies does not have to be interpreted by the MN 1702/1802. Upon receiving the SN Addition Request Ack form the T-SN 1704/1804, the MN 1702/1802 sends a message to the S-SN 1700/1800 with the further information on the selected cell candidates and/or frequencies and starts a timer. If the timer expires and no message from the S-SN 1700/1800 is received to indicate the update of the SCG measConfig for CPC, the MN 1702/1802 generates the RRCReconfiguration including CPC, including the stored SCG measConfig for CPC (e.g., received in the SN Change Required) and sends it to the UE 1706/1806. Else, if the MN 1702/1802 receives a message from the S-SN 1700/1800 while the timer is running, to indicate the update of the SCG measConfig for CPC, the MN 1702/1802 uses the updated SCG measConfig for CPC and generates the RRCReconfiguration including CPC, including the updated SCG measConfig for CPC (e.g., received in the SN Change Required) and sends it to the UE 1706/1806.
In yet another option, the further information on the selected cell candidates and/or frequencies is limited to a simplified indication, indicating whether all frequencies and/or cells have been selected or not by the T-SN 1704/1804.
In this set of embodiments, the S-SN provides multiple versions of the SCG measConfig for CPC in the first message to the MN, e.g. in the SN Change Required. The versions are associated to the target candidate cells/frequencies the S-SN includes the message to the MN and, based on the further information on the selected cell candidates and/or frequencies from the T-SN candidate, the MN selects which version of the SCG measConfig for CPC it uses to configure the UE.
Step 1908: In one set of embodiments, the S-SN 1900 transmits a message to the MN 1902 (e.g., SN Change Required) including an indication this is for a Conditional Reconfiguration (e.g., CPC) and including information of target candidate cells of at least one target candidate SN (e.g., N target candidate PSCell, including measurement results for at least one PSCell candidate), possibly in different frequency (e.g., having different SSB frequency/ARFCN for the SSB). The various way that information can be included can be as described in Solution 1, e.g. in CG-Config container. In this example, the at least one target candidate SN includes the T-SN 1904.
In addition, the message of step 1908 includes at least one of the following:
Step 1910: Upon reception, the MN 1902 stores the different versions of the SCG MeasConfig for CPC and/or the execution conditions (and association to target cell and/or frequency candidates).
The method also comprises the possibility that the S-SN 1900 includes (e.g., in the SN Change Required for CPC) multiple version of measurement gap configurations to the UE 1906, each associated to a set of frequencies (which may be known to the UE 1906 or only know to the network, e.g. to the S-SN 1900). That message may also include measurement gap related configuration to the MN 1902 (e.g., in the RRC container or in XnAP) so that the MN 1902 knows which measurement gap the UE 1906 may be configured with, so that it acts accordingly, e.g. when scheduling the UE 1906, taking gaps for measurements into account.
Another alternative is to define the inclusion of the multiple versions of the SCG measConfig for CPC and/or the execution conditions per cell/frequency candidates in the message from the S-SN 1900 to the MN 1902 (e.g., in the SN Change Required) as optional. If that is included, the S-SN 1900 wants to indicate that a second procedure for updating the SCG measConfig for CPC is not required. If that is not included in the message, the MN 1902 is aware that is needs to act as defined in Solution 1 (i.e., it always waits for a second procedure triggered by the S-SN 1900).
Step 1912) This is similar to Step 1110) in Solution 1.
Step 1914) After the selection, the (candidate) T-SN 1904 sends a message to the MN 1902 (e.g., SN Addition Request Ack) including the information of the selected candidate cells to the MN 1902, including for each selected candidate an RRC Reconfiguration to be applied upon the fulfillment of the execution condition, denoted RRCReconfiguration** (this is the SCG configuration to be provided to the UE as part of the MN generated CPC configuration).
The T-SN 1904, in the SN Addition Request Ack, includes further information on the selected cell candidates and/or frequencies. That information can be, for example, a list of cell identity (e.g., physical cell identity, global cell identity)+frequency information. There are different possible ways to encode this information in the SN Addition Request Ack message, as described in Step 1112) of Solution 1 e.g. using a single CG-Config container. Even if the T-SN 1904 has selected multiple target candidate cells, a single container may be used but within the container there are multiple RRC Reconfiguration messages (denoted RRCReconfiguration(s)**) to be applied by the UE 1906 upon fulfillment of the execution condition, where there is at least one RRC Reconfiguration message per target candidate cell that has been selected.
Step 1916: In one option, the further information on the selected cell candidates and/or frequencies can be interpreted by the MN 1902 (e.g., is included in text format understandable by the MN 1902, e.g., in XnAP). The MN 1902 determines which SCG MeasConfig to configure the UE 1906 based on the further information on the selected cell candidates and/or frequencies. If we use the previous example for the versions provided to the MN 1902, and if the T-SN 1904 indicates that only cells of frequency A were selected as candidates, then the MN 1902 selects SCG measConfig(1); if the T-SN 1904 indicates that only cells of frequency B were selected as candidates, then the MN 1902 selects SCG measConfig(2); if the T-SN 1904 indicates that cells of both frequencies A and B were selected as candidates, then the MN 1902 selects SCG measConfig(3).
Steps 1918 and 1920: After the MN 1902 selects the SCG MeasConfig for CPC, and the execution condition(s) for the selected cells/frequencies the follow up steps between the MN 1902 and the UE 1906 are similar to the steps defined with respect to Solution 1 for step 1120) and step 1122).
Step 1922: In one option, after the MN 1902 receives the RRCReconfigurationComplete message from the UE 1906 (or equivalent message that acks the reception of the CPC configuration), the MN 1902 sends to the S-SN an SN Change Confirm, possibly including an indication of the selected cells and/or frequencies by the T-SN.
Solution 4: UE Ignores or Releases Unnecessary SCG measConfig for CPC
Step 2008: In one set of embodiments, the S-SN 2000 transmits a message to the MN 2002 (e.g., SN Change Required) including an indication this is for a Conditional Reconfiguration (e.g., CPC) and including information of target candidate cells of at least one target candidate SN (e.g., N target candidate PSCell, including measurement results for at least one PSCell candidate), possibly in different frequency (e.g., having different SSB frequency/ARFCN for the SSB). The various way that information can be included can be as described in Solution 1, e.g. in CG-Config container. In this example, the at least one target candidate SN includes the T-SN 1104.
In addition, the message includes the execution conditions (i.e., the measId(s) associated to the target candidate cells and/or frequencies) and/or the SCG measConfig for CPC. The SCG MeasConfig for CPC may also include a measurement gap configuration for the UE 2006 to perform measurement in frequencies of the of the PSCell candidates, if needed. The message may also include information on the measurement gaps from the S-SN 2000 to the MN 2002. There are different ways to include the execution conditions in the message from the S-SN 2000 to the MN 2002, as described further below.
Step 2010: Upon reception, the MN 2002 stores the SCG MeasConfig for CPC and/or the execution conditions (and association to target cell and/or frequency candidates). This is used later by the MN 2002 to understand which execution conditions it needs to select to generate the CPC configuration to be included in the RRCReconfiguration that is sent to the UE 2006.
Another alternative is to define the inclusion of the SCG measConfig for CPC in the message from the S-SN 2000 to the MN 2002 (e.g., in the SN Change Required) as optional. If that is included, the S-SN 2000 wants to indicate that this is to be provided to the UE 2006, regardless of the outcome of the selected cells and/or frequency by the candidate T-SN 2004.
Step 2012: This is similar to Step 1110) in Solution 1.
Step 2014: After the selection, the candidate T-SN 2004 sends a message to the MN 2002 (e.g., SN Addition Request Ack) including the information of the selected candidate cells to the MN 2000, including for each selected candidate an RRC Reconfiguration to be applied upon the fulfillment of the execution condition, denoted RRCReconfiguration** (this is the SCG configuration to be provided to the UE as part of the MN generated CPC configuration).
The T-SN 2000, in the SN Addition Request Ack, includes further information on the selected cell candidates and/or frequencies. That information can be, for example, a list of cell identity (e.g., physical cell identity, global cell identity)+frequency information. There are different possible ways to encode this information in the SN Addition Request Ack message, as described in Step 1112) of Solution 1.
Step 2016: In one option, the further information on the selected cell candidates and/or frequencies can be interpreted by the MN 2002 (e.g., is included in text format understandable by the MN 2002, e.g., in XnAP). Based on that, the MN 2002 determines which execution conditions are to be provided to the UE 2006. The whole set of execution conditions have been provided by the S-SN 2006 in the first message (e.g., the SN Change Required, possibly in the CG-Config container), from which the MN 2002 needs to select the execution conditions associated to the selected frequencies (if conditions are defined per frequency) and/or per cell (if conditions are defined per cell).
Step 2018: Upon reception of the message from the T-SN 2004 (e.g., SN Addition Request Ack) and making the determination of step 2016, the MN 2002 generates CPC in MN format. The MN 2002 generates the main MN message (RRCReconfiguration) to be applied by the UE 2006 upon reception, including the Information Element (IE) Conditional Reconfiguration and the CondReconfigToAddModList, as in
Then, the MN 2002 generates the CondReconfigToAddMod for each target candidate cell. There can be different options, depending on whether the execution condition is transparent to the MN 2002 or not. In the first sub-option, shown in
In a second sub-option, the execution condition set by the S-SN 2000 is not transparent to the MN 2002, and in that case, there is no need of a new field/IE in CondReconfigToAddMod. Instead, the MN 2002 sets the condExecutionCond-r16 to the one or two (or more) integers indicated by the S-SN 2000 as the execution conditions for the corresponding candidate frequency and/or cell.
Then, within each condRRCReconfig for a given target candidate, the MN 2002 generates an RRCReconfiguration in MN format (denoted RRCReconfiguration*) including as its SCG configuration the RRCReconfiguration** for each selected target candidate cell, as provided by the T-SN 2004.
Step 2020. The UE 2006 receives the RRCReconfiguration including an SCG container (denoted an RRCReconfiguration*** including an SCG MeasConfig for CPC and set as nr-scg, in case of NR), and including a CPC configuration (in MN format), IE ConditionalReconfiguration. Then, within the SCG MeasConfig for CPC, the UE 2006 ignores and/or releases the measId(s) not referred in the CPC configuration, i.e. not pointed as an execution condition in the CPC configuration. In other words, for each measId, before the UE 2006 determines whether a measId is configured in SCG MeasConfig for CPC is to be measured, the UE 2006 first checks if the measId(s) associated to CPC (i.e., reporting configuration indicates reportType set to conditional reconfiguration and/or CPC) is included in the CPC configuration, i.e., if it included as an execution condition for a configured target candidate cell.
For example, if the UE 2006 receives an SCG measConfig including configurations for measId=1, measId=2, measId=3, all of them having reporting configuration associated to a conditional reconfiguration, e.g., each reportType is set to condTriggerConfig-r16 of Information Element (IE) CondTriggerConfig-r16). And, if the execution condition in CPC for target candidate cell A is set to measId=1, the UE 2006 performs measurements associated to measId=1. But if there is no execution condition in CPC set to measId=2 or measId=3, the UE 2006 does not have to perform measurements associated to measId=2 or measId=3. And, in addition, it may release the configurations associated to measId=2 or measId=3 (e.g., reportConfig is not referred to other measId referred as execution conditions).
In one option, to be required to perform a measurement associated to a measId in the SCG measConfig, the following condition would need to be fulfilled:
Below, an example of how this can be defined in the RRC specifications is shown.
[ . . . ]
The UE shall:
[ . . . ]
The method also comprises the UE 2006 selecting an appropriated measurement gap configuration depending on the frequencies (and/or measurement objects) it needs to perform measurements for CPC. For example, the UE 2006 may have been provided in the SCG measConfig with one or multiple gap configurations, that depend on the frequencies the UE 2006 needs to measure. And, upon determining the measId(s) used as execution conditions in the CPC configuration, the UE 2006 determines which frequencies are also to be measured i.e., the ones associated to the measurement objects referred by the measId(s) used as execution conditions in the CPC configuration. Then, upon determining these frequencies and measurement objects, the UE 2006 determines which measurement gap configuration it should use (i.e., it should apply). That assumes that in the measurement gap configuration(s) there is an indication of which frequencies and/or frequency combinations they are associated with.
An example is shown in
Further Details about the Execution Condition(s) Per Target Candidate Frequency/Cell
In one option, a message can include a mapping between measId(s) for CPC per frequency. In other words, there is an execution condition per frequency associated to one or more measId(s).
In one option, the mapping between measId(s) for CPC per frequency is included in the candidateCellInfoListSN, as one of the configurations in MeasResultList2NR (where each instance has an associated frequency, like ssbFrequency and/or refFreqCSI-RS).
One example is shown below, with the case the execution condition per frequency is transparent to the MN. Or, in more general terms, being within the container as something to be included in the MN generated CPC as a new field, enables the UE to distinguish between an execution condition/measId(s) associated to an MCG MeasConfig and an execution condition/measId(s) associated to an SCG MeasConfig, i.e. the new field becomes the indicator to the UE that the execution condition/measId(s) is associated to an SCG MeasConfig (i.e., the measId(s) are configured in the SCG MeasConfig). More details are given later in the UE actions.
[ . . . ]
Direction: Secondary gNB or eNB to master gNB or eNB, alternatively CU to DU.
The IE MeasResult2NR contains measurements on NR frequencies. That may contain the configuration of the execution condition per frequency for CPC.
The fact that the condition is transparent does not necessarily mean the T-SN needs to receive it via the SN Addition Request from the MN, i.e., the MN could remove the field before transmitting to the T-SN.
In another option, assuming there needs to be another round trip/procedure between the S-SN and the MN after the T-SN determines which PSCells to configuration for CPC (i.e. an additional procedure), so the MN can obtain the SCG MeasConfig from the S-SN for the selected candidate PSCell and/or selected frequencies by the T-SN candidate, the mapping between the execution condition (e.g. 1 or multiple measId(s)) and a candidate PSCell may not need to be provided in this first step i.e. not needed in the SN Change Required. Instead, that could be provided in the next round trip/procedure, together with the SCG MeasConfig. The benefit would be if the MN typically includes the CG-Config container from the S-SN in the SN Addition Request, without any change, it would not need to include the execution conditions (not supposed to be interpreted by the T-SN), e.g. condExecutionCond2. This is further explained in the other set of embodiments. And, the S-SN would not need to generate unnecessary configurations (i.e. execution conditions and SCG MeasConfig for CPC) that may anyways need to be updated (based on which candidate cells the T-SN has accepted).
Another example is shown below, with the case the execution condition is set per frequency and per cell, transparent to the MN. For example, the execution condition can be configured within measResultNeighCellListNR, as shown below:
New Field for the Execution Condition(s) Indicating the measId is in SCG MeasConfig
The method comprises the UE determining whether a given measId referred in the execution condition configuration for CPC is associated to an SCG measConfig or to an MCG measConfig, based on the field configuring the execution condition.
In other words, the IE CondReconfigToAddMod is enhanced with a new field indicating an execution condition, e.g. condExecutionCond2-r17, defined as an optional field. This means that when a target candidate is configured in CondReconfigToAddMod to the UE, that can either include the field condExecutionCond-r16 or the field condExecutionCond2-r17, wherein each of them includes a pointer to one or more (e.g., 2) MeasID(s), as shown above. The method comprises the UE receiving one of these two fields and based on the one it receives, determining whether the associated/pointed MeasId(s) are configured in SCG MeasConfig or MCG MeasConfig.
If the UE receives in the CondReconfigToAddMod the legacy field condExecutionCond-r16, the associated measId(s) are the ones referred in the MCG MeasConfig. Else, If the UE receives in the CondReconfigToAddMod the new field, e.g. condExecutionCond2-r17, the associated measId(s) are the ones referred in the SCG MeasConfig. That is a way to use the new field as a way to indicate to the UE that despite the fact that the CondReconfigToAddMod is part of the MCG configuration, as in Conditional Handover, Conditional PSCell Addition, MN/SN-initiated Conditional PSCell Change, the configuration for the measurements is within the SCG MeasConfig.
Step 2020: The UE 2006 confirms the configuration of CPC with an RRCReconfigurationComplete or equivalent message.
Step 2022: The MN 2002 replies to S-SN 2002 with an S-NODE CHANGE CONFIRM message, confirming the configuration of CPC. In one option, after the MN 2002 receives the RRCReconfigurationComplete message from the UE 2006 (or equivalent message that acks the reception of the CPC configuration), the SN Change Confirm may include an indication of the selected cells and/or frequencies by the T-SN 2004.
As used herein, a “virtualized” radio access node is an implementation of the radio access node 2600 in which at least a portion of the functionality of the radio access node 2600 is implemented as a virtual component(s) (e.g., via a virtual machine(s) executing on a physical processing node(s) in a network(s)). As illustrated, in this example, the radio access node 2600 may include the control system 2602 and/or the one or more radio units 2610, as described above. The control system 2602 may be connected to the radio unit(s) 2610 via, for example, an optical cable or the like. The radio access node 2600 includes one or more processing nodes 2700 coupled to or included as part of a network(s) 2702. If present, the control system 2602 or the radio unit(s) are connected to the processing node(s) 2700 via the network 2702. Each processing node 2700 includes one or more processors 2704 (e.g., CPUs, ASICs, FPGAs, and/or the like), memory 2706, and a network interface 2708.
In this example, functions 2710 of the radio access node 2600 described herein are implemented at the one or more processing nodes 2700 or distributed across the one or more processing nodes 2700 and the control system 2602 and/or the radio unit(s) 2610 in any desired manner. In some particular embodiments, some or all of the functions 2710 of the radio access node 2600 described herein are implemented as virtual components executed by one or more virtual machines implemented in a virtual environment(s) hosted by the processing node(s) 2700. As will be appreciated by one of ordinary skill in the art, additional signaling or communication between the processing node(s) 2700 and the control system 2602 is used in order to carry out at least some of the desired functions 2710. Notably, in some embodiments, the control system 2602 may not be included, in which case the radio unit(s) 2610 communicate directly with the processing node(s) 2700 via an appropriate network interface(s).
In some embodiments, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of radio access node 2600 or a node (e.g., a processing node 2700) implementing one or more of the functions 2710 of the radio access node 2600 in a virtual environment according to any of the embodiments described herein is provided. In some embodiments, a carrier comprising the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory).
In some embodiments, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of the wireless communication device 2900 according to any of the embodiments described herein is provided. In some embodiments, a carrier comprising the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory).
Any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses. Each virtual apparatus may comprise a number of these functional units. These functional units may be implemented via processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include Digital Signal Processor (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as Read Only Memory (ROM), Random Access Memory (RAM), cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and/or data communications protocols as well as instructions for carrying out one or more of the techniques described herein. In some implementations, the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according one or more embodiments of the present disclosure.
While processes in the figures may show a particular order of operations performed by certain embodiments of the present disclosure, it should be understood that such order is exemplary (e.g., alternative embodiments may perform the operations in a different order, combine certain operations, overlap certain operations, etc.).
Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein.
This application claims the benefit of provisional patent application Ser. No. 63/144,950, filed Feb. 2, 2021, the disclosure of which is hereby incorporated herein by reference in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/SE2022/050094 | 1/28/2022 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63144950 | Feb 2021 | US |
