Patent Description:
The purpose of the RLM function in the UE is to monitor the downlink radio link quality of the serving cell in RRC_CONNECTED state and is based on the Cell-Specific Reference Signals (CRS), which is always associated to a given LTE cell and derived from the Physical Cell Identifier (PCI). This, in turn, enables the UE when in RRC_CONNECTED state to determine whether it is in-sync or out-of-sync with respect to its serving cell.

The UE's estimate of the downlink radio link quality is compared with out-of-sync (OOS) and in-sync (IS) thresholds, which may be referred to as Qout and Qin, respectively, for the purpose of RLM. These thresholds are expressed in terms of the Block Error Rate (BLER) of a hypothetical Physical Downlink Control Channel (PDCCH) transmission from the serving cell. Specifically, Qout corresponds to a <NUM>% BLER while Qin corresponds to a <NUM>% BLER. The same threshold levels are applicable with and without DRX.

<CIT> describes RLM monitoring to determine whether a UE is in-sync or out-of-sync with an access point.

The mapping between the CRS based downlink quality and the hypothetical PDCCH BLER is up to the UE implementation. However, the performance is verified by conformance tests defined for various environments. Also, the downlink quality is calculated based on the RSRP of CRS over the whole band since UE does not necessarily know where PDCCH is going to be scheduled, which is illustrated in <FIG>, which illustrates that PDCCH can be scheduled anywhere over the whole downlink transmission bandwidth.

When no DRX is configured, OOS occurs when the downlink radio link quality estimated over the last <NUM> period becomes worse than the threshold Qout. Similarly, without DRX the IS occurs when the downlink radio link quality estimated over the last <NUM> period becomes better than the threshold Qin. Upon detection of out-of-sync, the UE initiates the evaluation of in-sync.

The key question in the RLF functionality is how the higher layers use the internally generated IS/OOS events from RLM to control the UE autonomous actions when it detects that is cannot be reached by the network while in RRC_CONNECTED.

In LTE, the occurrences of OOS and IS events are reported internally by the UE's physical layer to its higher layers, which in turn may apply RRC / layer <NUM> (i.e. higher layer) filtering for the evaluation of Radio Link Failure (RLF). <FIG> illustrates higher layer RLM procedures in LTE.

The details UE actions related to RLF are captured in the RRC specifications (<NUM>).

For NR, frequency ranges up to <NUM> are considered. High-frequency radio communication above <NUM> suffers from significant path loss and penetration loss. Therefore massive MIMO schemes for NR are considered.

With massive MIMO, three approaches to beamforming have been discussed: analog, digital, and hybrid (a combination of the two). <FIG> illustrates an example diagram for hybrid beamforming. Beamforming can be on transmission beams and/or reception beams, network side or UE side.

The analog beam of a subarray can be steered toward a single direction on each OFDM symbol, and hence the number of subarrays determines the number of beam directions and the corresponding coverage on each OFDM symbol. However, the number of beams to cover the whole serving area is typically larger than the number of subarrays, especially when the individual beam-width is narrow. Therefore, to cover the whole serving area, multiple transmissions with narrow beams differently steered in time domain are also likely to be needed. The provision of multiple narrow coverage beams for this purpose has been called "beam sweeping". For analog and hybrid beamforming, the beam sweeping seems to be essential to provide the basic coverage in NR. For this purpose, multiple OFDM symbols, in which differently steered beams can be transmitted through subarrays, can be assigned and periodically transmitted.

<FIG> illustrates TX beam sweeping on <NUM> subarrays.

SS block and SS burst configuration are now described. The signals comprised in SS block may be used for measurements on NR carrier, including intra-frequency, inter-frequency and inter-RAT (i.e., NR measurements from another RAT).

SSB, NR-PSS, NR-SSS and/or NR-PBCH can be transmitted within an SS block, which can also be referred to as SS/PBCH block. For a given frequency band, an SS block corresponds to N OFDM symbols based on one subcarrier spacing (e.g., default or configured), and N is a constant. UE shall be able to identify at least OFDM symbol index, slot index in a radio frame and radio frame number from an SS block. A single set of possible SS block time locations (e.g., with respect to radio frame or with respect to SS burst set) is specified per frequency band. At least for multi-beams case, at least the time index of SS-block is indicated to the UE. The position(s) of actual transmitted SS-blocks can be informed for helping CONNECTED/IDLE mode measurement, for helping CONNECTED mode UE to receive DL data/control in unused SS-blocks and potentially for helping IDLE mode UE to receive DL data/control in unused SS-blocks. The maximum number of SS-blocks within SS burst set, L, for different frequency ranges are:.

By contrast, one or multiple SS burst(s) further compose an SS burst set (or series) where the number of SS bursts within a SS burst set is finite. From physical layer specification perspective, at least one periodicity of SS burst set is supported. From UE perspective, SS burst set transmission is periodic. At least for initial cell selection, UE may assume a default periodicity of SS burst set transmission for a given carrier frequency (e.g., one of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>). UE may assume that a given SS block is repeated with a SS burst set periodicity. By default, the UE may neither assume the gNB transmits the same number of physical beam(s), nor the same physical beam(s) across different SS-blocks within an SS burst set. In a special case, an SS burst set may comprise one SS burst.

For each carrier, the SS blocks may be time-aligned or overlap fully or at least in part, or the beginning of the SS blocks may be time-aligned (e.g., when the actual number of transmitted SS blocks is different in different cells). <FIG> illustrates an example configuration of SS blocks, SS bursts, and SS burst sets/series.

All SS blocks within a burst set are within <NUM> window, but the number of SS blocks within such window depends on the numerology (e.g., up to <NUM> SS blocks with <NUM> subcarrier spacing). <FIG> illustrates an example mapping for SS blocks within a time slot and within the <NUM> window.

With regard to CSI-RS activation by MAC CE in LTE, the CSI-RS activation/deactivation by MAC CE command is specified in TS36. <NUM> (e.g., see <NPL>) where Section <NUM> describes:
The network may activate and deactivate the configured CSI-RS resources of a serving cell by sending the Activation/Deactivation of CSI-RS resources MAC control element described in subclause <NUM>.

The configured CSI-RS resources are initially deactivated upon configuration and after a handover.

The Activation/Deactivation of CSI-RS resources MAC control element is identified by a MAC PDU subheader with LCID as specified in table <NUM>. <NUM>-<NUM>. It has variable size as the number of configured CSI process (N) and is defined in Figure <NUM>. <NUM>-<NUM>. Activation/Deactivation CSI-RS command is defined in Figure <NUM>. <NUM>-<NUM> and activates or deactivates CSI-RS resources for a CSI process. Activation/Deactivation of CSI-RS resources MAC control element applies to the serving cell on which the UE receives the Activation/Deactivation of CSI-RS resources MAC control element.

The Activation/Deactivation of CSI-RS resources MAC control elements is defined as follows:.

<FIG> illustrates activation/deactivation of CSI-RS resources by MAC Control element.

<FIG> illustrates activation/deactivation of CSI-RS resources by CSI-RS command.

The MAC activation was introduced in LTE to be able to configure more CSI-RS resources for a UE that the UE is able to support feedback for as the MAC CE would selective activate up to max CSI-RS resources supported. Then, without the need to reconfigure by RRC, network may activate another set among the resources configured for the UE.

With regard to MAC CE usage in NR, the MAC CEs agreed for NR are listed.

With regard to RLM handing in NR, two types of reference signals (RS Types) are defined for L3 mobility: PBCH/SS Block (SSB or SS Block), which basically comprises synchronization signals equivalent to PSS/SSS in LTE and PBCH/DMRS, and, CSI-RS for L3 mobility, more configurable and configured via dedicated signalling. There are different reasons to define the two RS types, one of them being the possibility to transmit SSBs in wide beams while CSI-RSs in narrow beams.

In RAN1# NR AdHoc#<NUM>, it has been agreed that in NR the RS type used for RLM is also configurable (both CSI-RS based RLM and SS block based RLM are supported) and, it seems natural that the RS type for RLM should be configured via RRC signalling. In RAN1#<NUM>, further progress was reached and it was agreed to support single RLM-RS type only to different RLM-RS resources for a UE at a time.

As NR can operate in quite high frequencies (above <NUM>, but up to <NUM>), these RS types used for RLM can be beamformed. In other words, depending on deployment or operating frequency, the UE can be configured to monitor beamformed reference signals regardless which RS type is selected for RLM. Hence, differently from LTE, RS for RLM can be transmitted in multiple beams.

In the case of CSI-RS, the time/frequency resource and sequence can be used. As there can be multiple beams, the UE needs to know which ones to monitor for RLM and how to generate IS/OOS events. In the case of SSB, each beam can be identified by an SSB index (derived from a time index in PBCH and/or a PBCH/DMRS scrambling). In RAN1#<NUM>, it has been agreed that this is configurable and, in NR the network can configure by RRC signalling, X RLM resources, either related to SS blocks or CSI-RS, as follows:.

In RAN2#<NUM> in Nanjing, the first meeting we have discussed NR mobility, the following has been agreed:
Two levels of network controlled mobility:.

Since then, it has always been assumed at least in RAN2 that inter-cell mobility relies on RRC level, while intra-cell mobility (which includes beam management procedures within the same cell) should not have RRC involvement.

However, in RAN1#<NUM> the following has been agreed:.

Then, in RAN1#90bis, it has been greed that the value of X should be limited, as follows:.

Then in RAN1#<NUM>, it has been agreed that the value of X for the maximum number of resources could vary for different frequency ranges, as follows:.

There currently exist certain challenge(s). To help understand them, the consequences of these agreements must be considered. It has also been agreed in RAN1 that the number of SSBs covering a cell can also vary per frequency range, and the following values have been agreed in RAN1#88bis:.

Then, especially for SSB-based RLM, if we compare the values of L (maximum number of transmitted SSBs for cells in a given frequency range) and X (maximum number of RLM-RS resources for a given frequency range), we will have scenarios where X is lower than L, as shown below:.

As it can be seen from the table above, the number of beams (the term 'beams' may be used instead of RLM-RS resources) that can be configured for RLM is smaller than the number of beams possibly providing cell coverage. <FIG> illustrates this scenario for frequencies between <NUM> and <NUM> where L=<NUM> and X=<NUM> (i.e. for frequencies between <NUM> and <NUM>). Then, if the UE moves within the coverage of that cell, the beams to be used for RLM may need to be re-configured, otherwise the UE would possibly start generating OSS events (and possibly declare RLF) even though the UE is still under cell coverage.

When that situation happens, what the network would likely want to be able to do is to reconfigure both the beams serving the UE with PDCCH and, consequently, the beams to be monitored for RLM (as these should be correlated). <FIG> illustrates the network re-configuring the PDCCH beams and consequently the RS-RLM resources/beams.

However, certain problems with the baseline solution exist. For exmaple, RRC signaling is usually considered for re-configurations in mobile networks, and hence, it could be assumed every time the UE needs to re-configure RLM-RS parameters such as the as a baseline solution. However, a consequence of the RAN1 decision to have X<L is that, if only RLM-RS re-configuration mechanisms allowed is the one based on RRC, UE would likely require RRC signalling to perform intra-cell mobility, which goes against the very first NR mobility agreement in RAN2. Thus, an observation is that current RAN1 assumptions on the maximum RLM-RS resources (equals to <NUM>) requires intra-cell RRC based mobility, which is against RAN2 early agreement.

Certain aspects of the present disclosure and their embodiments may provide solutions to these or other challenges. For example, a method is disclosed that includes a configuration and re-configuration framework for RLM parameters such as, for example, RLM-RS resources. The method includes the UE being configured with a set of RLM configurations via RRC signalling send by the network and these configurations being possibly updated for example, by activation/deactivation, via lower layer signalling such as, for example, using MAC CEs, DCIs, or other signalling.

The invention is defined in the independent claims, to which reference should now be made. Advantageous optional features are included in the dependent claims.

Certain embodiments may provide one or more of the following technical advantage(s). For example, a technical advantage of certain embodiments may include avoiding or minimizing RRC signalling due to intra-cell mobility. In particular, these advantages may be experienced when the RLM parameters need to be updated due to intra-cell mobility.

In some embodiments a non-limiting term "UE" is used. The UE herein can be any type of wireless device capable of communicating with network node or another UE over radio signals. The UE may also be radio communication device, target device, device to device (D2D) UE, machine type UE or UE capable of machine to machine communication (M2M), a sensor equipped with UE, iPAD, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE) etc..

Also in some embodiments generic terminology "network node", is used. It can be any kind of network node which may comprise of a radio network node such as base station, radio base station, base transceiver station, base station controller, network controller, multi-standard radio BS, gNB, en-gNB, ng-eNB, NR BS, evolved Node B (eNB), Node B, Multi-cell/multicast Coordination Entity (MCE), relay node, access point, radio access point, Remote Radio Unit (RRU) Remote Radio Head (RRH), a multi-standard BS (a. MSR BS), a core network node (e.g., MME, SON node, a coordinating node, positioning node, MDT node, etc.), or even an external node (e.g., <NUM>rd party node, a node external to the current network), etc. The network node may also comprise a test equipment.

The term "BS" may comprise, e.g., gNB, en-gNB or ng-eNB or a relay node, or any BS compliant with the embodiments.

The term "radio node" used herein may be used to denote a UE or a radio network node.

The term "signaling" used herein may comprise any of: high-layer signaling (e.g., via RRC or a like), lower-layer signaling (e.g., via a physical control channel or a broadcast channel), or a combination thereof. The signaling may be implicit or explicit. The signaling may further be unicast, multicast or broadcast. The signaling may also be directly to another node or via a third node.

The term RLM procedure used herein may refer to any process occurs or action taken by the UE during the RLM. Examples of such processes or actions are OOS evaluation, IS evaluation, filtering of IS/OOS (e.g. start of counters), triggering of RLF, start or expiration of RLF timer etc..

The term RLM performance used herein may refer to any criteria or metric which characterizes the performance of the RLM performed by a radio node. Examples of RLM performance criteria are evaluation period over which the IS/OOS are detected, time period within which the UE transmitter is to be turned off upon expiration of RLF timer etc..

The term numerology here may comprise any one or a combination of: subcarrier spacing, number of subcarriers within a bandwidth, resource block size, symbol length, CP length, etc. In one specific non-limiting example, numerology comprises subcarrier spacing of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>. In another example, numerology is the CP length which may be used with subcarrier spacing <NUM> or larger.

According to certain embodiments, a method is provided that includes a configuration and re-configuration framework for RLM parameters, which may include, as one example, RLM-RS resources. <FIG> illustrates an example method <NUM> that includes the UE being configured with a set of RLM configurations via RRC signalling sent by the network at step <NUM>, according to certain embodiments. As depicted, the configurations are possibly updated such as, for exmaple, by activation/deactivation, via lower layer signalling at step <NUM>, which may include using MAC Ces, DCIs, or other signalling elements.

Additional details described below include:.

Other techniques have been proposed for NR changing a set of RLM-RS resources. For example, re-configurations of RLM parameters has been proposed elsewhere. However, the focus in those disclosures is not at all related to trying to make the re-configuration framework as efficient as possible. Rather, it was proposed that for the different kinds of re-configurations of RLM parameters there could be different UE actions that should be taken depending on the configuration. As disclosed herein, however, the focus is on making the re-configuration framework as efficient as possible to avoid/minimize the intra-cell RRC signalling.

As another example, there have previous disclosures relating to RLM re-configuration upon BWP switching. More specifically, a method has been proposed where the UE is configured by the network with one or multiple RLM configuration(s) or determines (e.g., based on a pre-defined rule) one or more RLM configuration parameters based on the active BWP or the set of active BWPs. One of them can be configured by the network or determined by the UE (e-g-. based on a pre-defined rule) as active RLM configuration. There may also be a default RLM reconfiguration, which is configured by the network, specified by the standard, or determined by the UE based on a pre-defined rule; the default RLM configuration may or may not be further associated with a default BWP. By contrast, in the techniques disclosed herein, each RLM configuration comprises at least one set of radio resources and configuration parameters for doing RLM within one bandwidth part (BWP).

Further, the change proposed in previous solutions is a change of RLM configurations when there is a change in BWP. Meanwhile, the techniques disclosed herein are applied in the case where the RLM parameters must be changed even if the UE is still within the same BWP such as, for example, when there is the need for an optimized RLM re-configuration framework even though the UE remains in the same BWP, e.g., due to intra-cell mobility.

With regard to the RLM configuration(s)/reconfiguration(s) the UE may receive via higher layer signaling, according to a first set of embodiments, the UE may receive from the network a mapping between one or multiple (e.g. N1) RLM configuration(s) and a set of indexes and applies that configuration. One such example mapping is shown in Table <NUM>:.

The higher layer message can also indicate to the UE (implicitly or explicitly) which configuration should be activated upon receiving the higher layer message. By doing the need for a follow up via a lower layer update message (e.g. MAC CE) may be avoided at least when the UE just receives the configuration from the higher layers such as, for example, when a handover occurs, when the UE is resuming or establishing a connection or when the network simply decides to re-configure RLM parameters with higher layer signalling.

The explicit indication could be a flag indicating a "default" configuration to be considered initially activated. The implicit indication for the default configuration could be simply a specific index in the set of configurations, such as the first index. UE uses that default the UE activates upon receiving the message and remains using until it receives a new configuration from higher layers to an update command from lower layers. If only one configuration is provided, that implicit indication means the UE only changes its RLM configuration via RRC signalling.

Each RLM configuration described in the table above can be related to different parameters of a combination of them.

According to certain embodiments, each RLM configuration in that table can be a set of RLM-RS resources. Thus, in a particular embodiment, each set of RLM-RS resources may have the same number of resources as there is a maximum number X of RLM-RS that can be monitored by the UE at time. Each RLM-RS configuration contains a set of X RLM-RS resources. In another embodiment, different RLM-RS configurations can have a different number of RLM-RS resources, which would increase the number of bits to encode the index that activates a given configuration via lower layer signalling but provides higher flexibility to the network.

For example, for frequencies < <NUM>, X can be up to <NUM> resources. As there can be up to L=<NUM> SSBs (SSB1, SSB2, SSB3, SSB4), the following combinations for the X RLM-Rs resources, if we only consider RS type as SSB for the sake of this example are listed in Table <NUM>:.

Although that could be the configuration/re-configuration provided by the network to the UE, there could be smarter network decisions in terms of avoiding certain configuration that might be quite unlikely to be used. For example, if SSB1 and SSB4 are quite far apart in the spatial domain and are never detected by the UE simultaneously anyway, there might be no point to even consider that configuration as a possible one to be ever activated by lower layer signalling. Hence, it might be the case that network /re-configures configures only a subset of likely configurations. That smart network implementation can have the potential to reduce the number of bits necessary to encode the index in the lower layer signalling (e.g. MAC CE). In this example, only adjacent beams are considered likely configurations. An example is shown below in Table <NUM>:.

Notice that although the maximum number of RLM-RS resources for a given frequency range is limited, e.g., <NUM> in the case of frequencies below <NUM>, the UE can still be configured with a lower number of RLM-RS resources. There could also be configurations mixing different number of resources single and double resources, as shown below in Table <NUM>:.

The previous example have shown only SSB resources as RLM-RS resources. However, not all embodiments are limited to that. Exactly the same reasoning could be applied for other two possible cases:.

For the first case (only CSI-RS resources as RLM-RS(s)), the previous examples would be quite similar except that instead of SSB index one would use a CSI-RS index, that can be associated to a CSI-Rs configuration (BW, sequence, time domain resources, exact frequency resources, subcarrier spacing, etc.). Table <NUM> repeats the first example but with CSI-RS:.

And, at least one example is shown in Table <NUM> with the combination of SSBs and CSI-RS resources, where a limited number of configurations is provided:.

Notice that the number of bits to be transmitted in the configuration activation/deactivation message (to be sent by the network via lower layers) increases as the number of configurations increase. Hence, to further have a more efficient scheme, a solution could be to limit the parameters to be activated via lower layer signalling, while other parameter could be defined via higher layers only. In one example embodiment, RS type is only configured via RRC, while the exact resources can be configured via RRC and activated via lower layer signalling. In another example embodiment, the other way around could be defined: the exact resource indexes are defined via RRC and the activation of one RS type or the other (SSB or CSI-RS) is done via lower layer signalling.

Although we have provided examples for the case where X=<NUM> and L=<NUM>, for frequencies < <NUM>, the method, examples and embodiments described above can be extended to the other cases too. The main difference would be the number of possibly or likely configurations and, possibly, the number of bits used to send the activation of a given configuration (i.e. the number of bits to encode the index of a particular configuration).

In other embodiments, the network simply informs the UE via the RRC signalling which SSBs are being transmitted by that cell. For example, although in higher layers (><NUM>) there can be up to <NUM> beams/SSBS, a network implementation might only be transmitting <NUM> and, the UE needs to be aware what are these <NUM> SSBs. In that sense, in this solution the UE can receive the exact <NUM> beams that are being transmitted, e.g., via a bitmap of <NUM> bits. One example is given:
First bitmap of SSBs transmitted: <NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM>.

The first <NUM> bits indicates to the UE that the first <NUM> SSBs are being transmitted by that cell. Hence, UE knows that for RLM based on SSB, only these <NUM> beams could be activated. Then, the UE could be configured (e.g. via RRC) with another bitmap to indicate which ones (up to <NUM>, as this is > <NUM>) are to be monitored for RLM. For example, assume the network decides to configure and activate the first <NUM> bits.

In one example, only <NUM> bits are used for the bitmap, where the exact SSB to be monitored for RLM is associated with the previous bitmap. The following example is associated to the previous example:
Second bitmap of SSBs to be used for RLM: <NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM>.

That bitmap indicates the UE shall monitor for RLM the following: SSB1, SSB2,. , SSB7 and SSB16. That bitmap can either be provided via RRC or lower layer signalling, e.g., MAC CE. The first time the second bitmap is provided can be done via RRC, while lower layer signaling can be used to change the RLM-RS resources by providing a different bitmap.

Now a different example is provided, where network decides to transmit intercalated <NUM> SSBs, out of <NUM> beams. That means the network transmits the following bitmap to indicate that:
First bitmap of SSBs transmitted: <NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM>. <NUM> The UE interpret that as network transmitting SSB1, SSB3, SSB5, SSB7,. Hence, UE knows that for RLM based on SSB, only these <NUM> beams could be activated SSB1, SSB3, SSB5, SSB7,. Hence, UE could be configured (e.g. via RRC) with another bitmap to indicate which ones (up to <NUM>, as this is > <NUM>) are to be monitored for RLM. For example, assume network decides to configure and activate the first <NUM> SSBs out of the ones being transmitted. Then, only <NUM> bits are used for the bitmap, where the exact SSB to be monitored for RLM is associated with the previous bitmap, i.e., the list SSB1, SSB3, SSB5, SSB7,. For example, the RLM bitmap can be the following:.

Second bitmap of SSBs to be used for RLM: <NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM> That bitmap indicates the UE shall monitor for RLM the following: SSB1, SSB3, SSB5, SSB7, SSB9, SSB11, SSB13 and SSB31. That bitmap can either be provided via RRC or lower layer signalling, e.g., MAC CE. The first time the second bitmap is provided can be done via RRC, while lower layer signaling can be used to change the RLM-RS resources by providing a different bitmap.

In yet another embodiment, each RLM configuration in the set described in the first table can be associated to one of the following parameters or a combination of these:.

In still another embodiment, a single RLM configuration is provided to the UE via RRC, to be the first one to be considered activated. Then, remaining re-configurations are handled by the lower layers, such as via MAC CEs.

With regard to the kind of higher layer messages (and associated scenarios) within which the UE may receive the RLM configuration/re-configurations, it is recognized that the RLM configuration(s) can be provided, for example, via one of the following RRC messages, according to certain embodiments:.

With regard to the kind of updates the UE does based on the messages transmitted via lower layer signalling related to the previously provided configuration(s)/re-configuration(s) via higher layer signalling (RRC), it is recognized that one alteration of the first embodiments is that a lower layer signalling, such as a MAC CE, encodes an index associated to one of the RLM configurations provided via higher layer signalling, such as the ones provided in the table(s) described above. Upon receiving that lower layer signaling the UE deactivates the previously active configuration, if any, and activates the one indicated by that lower layer signalling.

For example, if the following table has been provided via higher layer signalling in Table <NUM>:.

Each index can be transmitted via the MAC CE. In another embodiment, mainly applicable for the case where RLM-RS resources are the parameters to be updated, there can be a different mechanism based on lower layer signalling. For example, if the UE has a maximum number of RLM. RS resources, each MAC CEs can be used to indicate the UE that one of the following actions or a combination of them shall be performed:.

In another embodiment, mainly applicable for the case where RLM-RS resources are the parameters to be updated, there can be a different mechanism based on the lower layer signaling provides a bitmap to the UE indicating which exact RLM-RS resources out the ones previously provided to the UE (e.g. via RRC signalling) shall be monitored for RLM.

In yet another embodiment, an update of lower layer signalling of the PDDCH configuration, in particular the DL directions that PDCCH is to be detected by the UE, also triggers the UE to change the RLM-RS resources to be monitored. For example, if an indication from lower layers indicates to the UE that PDCCH will stop being transmitted in beams correlated/ quasi-collocated with a set of beams as SSB0, SSB1,. , SSB8 and will start to be transmitted in beams correlated/ quasi-collocated with another set of beams SSB1, SSB2,. , SSB9, the UE update its RLM-RS configuration from SSB0, SSB1,. , SSB8 to SSB1, SSB2,.

In yet another example embodiment, a MAC CE updates the set of RLM resources such that when UE receives the MAC CE, it considers the resources pointed by the MAC CE to be the current set of RLM resources. In addition to pointing to RLM resources the MAC CE optionally gives QCL information for the RLM resource.

The serving cell of the UE has L SSBs out of which a subset may be configured for the UE to be considered as potential RLM resources. Additionally, a UE may be configured with M CSI-RS resources or CSI-RS resource sets each having an ID. Here, M has a specified maximum value. Also, SSBs have IDs which are represented by a maximum of <NUM> bits. The maximum number of bits required to represent the IDs for CSI-RS resources or CSI-RS resource sets can be up to <NUM>. We denote the maximum number of bits required to represent the CSI-RS resource or CSI-RS resource set IDs by X.

Though <FIG> only shows the one octet, the MAC CE may contain as many of the below described octets as there are RLM resources in the activated set of RLM resources. In addition, according to certain embodiments, the MAC CE contains octets to describe the MAC CE type, give possibly cell and BWP index, and have a bit that describes if QCL info is present or not. Further in addition, the MAC CE may optionally contain QCL information in additional octets for each RLM resource by giving the QCL reference RS, SSB or CSI-RS index in an octet, in a particular embodiment.

Each of the octets giving RS index for RLM resource or the QCL info for that are formed such that bit R8 tells if the index is for SSB, R8 is set to <NUM>, or for CSI-RS R8 is set to <NUM>. The rest of the bits, R7 to R1 are used to give the index of the RLM resource, or QCL info reference resource. If less than <NUM> bits are needed then rest are padding bits ignored by MAC entity.

Which octet describes RLM resource and which QCL is predetermined. For example, if it is indicated that QCL info is present, then each RLM resource octet that gives CSI-RS resource is followed by an octet that gives QCL info. Or, after all RLM resources are given, the following octets give QCL info for each CSI-RS resource that was present in the order those where present.

When the UE receives the MAC CE that indicates a set of resources, the UE may compare that set to previous set. For those resources that existed also in the previous RLM RS set, UE continues the monitoring and the evaluations for IS/OOS. For new resources, UE starts the monitoring and evaluation for IS/OOS. For resources that are no longer in the set, UE stops monitoring and discards evaluations for IS/OOS.

The problem could be solved by network implementation in different manners. For exmaple, according to certain embodiments, a first alternative to the problem could be that the number of RLM-RS resources is aligned with the maximum number of RLM-RS resources and the maximum number of SSBs (i.e. align L and X).

In other embodiments, there could be yet other solutions such as never configuring SSB as RLM-RS and always rely on a set of UE-specific CSI-RS resources that are not re-configured towards the UE but could be beamformed in different directions by the network tracking/following the UE. That might work in scenarios with very few UEs, where UE-specific CSI-RS resources can be configured. On the other hand, this solution may be quite complex or unfeasible in the case the network wants to configure a set of CSI-RS resources periodically transmitted in the cell and shared across multiple UEs (although configuration is still provided in dedicated signaling). Notice that this solution can be used in combination with any of the previous embodiments to reduce the number of configuration and, consequently, the number of bits indicated via lower layer signalling. By possibly tracking the UE with CSI-RS, the network can configure a limited amount of CSI-RS resource sets, as in many cases tracking cam be used and there is no need to re-configure the UE with the activation mechanism via lower layer signalling.

According to still other embodiments, the problem may be addressed by limiting what can be deployed in terms of number of SSBs to what can be configured in terms of RLM RS resources. A manufacturer would never implement/deploy a network like that, and in practice would use L=X.

According to still other embodiments, another network related aspect may be that the operations executed by higher layers and lower layers could be executed by different nodes. In NR, a RAN architecture based on CU (central unit), possibly executing RRC functions and DU (distributed unit), possibly executing MAC functions. Hence, one aspect is that the DU and CU exchange these configurations/re-configurations and activation information that is provided to the UE so that both are up to date on the UE current configuration and activated RLM parameters.

<FIG> illustrates a wireless network, in accordance with some embodiments. Although the subject matter described herein may be implemented in any appropriate type of system using any suitable components, the embodiments disclosed herein are described in relation to a wireless network, such as the example wireless network illustrated in <FIG>. For simplicity, the wireless network of <FIG> only depicts network <NUM>, network nodes <NUM> and 160b, and WDs <NUM>, 110b, and 110c. In practice, a wireless network may further include any additional elements suitable to support communication between wireless devices or between a wireless device and another communication device, such as a landline telephone, a service provider, or any other network node or end device. Of the illustrated components, network node <NUM> and wireless device (WD) <NUM> are depicted with additional detail. The wireless network may provide communication and other types of services to one or more wireless devices to facilitate the wireless devices' access to and/or use of the services provided by, or via, the wireless network.

<FIG> illustrates an example network node <NUM>, according to certain embodiments.

<FIG> illustrates an example wireless device (WD) <NUM>, according to certain embodiments. As used herein, WD refers to a device capable, configured, arranged and/or operable to communicate wirelessly with network nodes and/or other wireless devices. Unless otherwise noted, the term WD may be used interchangeably herein with user equipment (UE). Communicating wirelessly may involve transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information through air. In some embodiments, a WD may be configured to transmit and/or receive information without direct human interaction. For instance, a WD may be designed to transmit information to a network on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the network. Examples of a WD include, but are not limited to, a smart phone, a mobile phone, a cell phone, a voice over IP (VoIP) phone, a wireless local loop phone, a desktop computer, a personal digital assistant (PDA), a wireless cameras, a gaming console or device, a music storage device, a playback appliance, a wearable terminal device, a wireless endpoint, a mobile station, a tablet, a laptop, a laptop-embedded equipment (LEE), a laptop-mounted equipment (LME), a smart device, a wireless customer-premise equipment (CPE). a vehicle-mounted wireless terminal device, etc.. A WD may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-everything (V2X) and may in this case be referred to as a D2D communication device. As yet another specific example, in an Internet of Things (IoT) scenario, a WD may represent a machine or other device that performs monitoring and/or measurements, and transmits the results of such monitoring and/or measurements to another WD and/or a network node. The WD may in this case be a machine-to-machine (M2M) device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the WD may be a UE implementing the 3GPP narrow band internet of things (NB-IoT) standard. Particular examples of such machines or devices are sensors, metering devices such as power meters, industrial machinery, or home or personal appliances (e.g. refrigerators, televisions, etc.) personal wearables (e.g., watches, fitness trackers, etc.). In other scenarios, a WD may represent a vehicle or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation. A WD as described above may represent the endpoint of a wireless connection, in which case the device may be referred to as a wireless terminal. Furthermore, a WD as described above may be mobile, in which case it may also be referred to as a mobile device or a mobile terminal.

As illustrated in <FIG>, wireless device <NUM> includes antenna <NUM>, interface <NUM>, processing circuitry <NUM>, device readable medium <NUM>, user interface equipment <NUM>, auxiliary equipment <NUM>, power source <NUM> and power circuitry <NUM>.

As illustrated in <FIG>, interface <NUM> comprises radio front end circuitry <NUM> and antenna <NUM>.

As illustrated in <FIG>, processing circuitry <NUM> includes one or more of RF transceiver circuitry <NUM>, baseband processing circuitry <NUM>, and application processing circuitry <NUM>.

<FIG> illustrates an example UE <NUM>, according to certain embodiments.

In FIURE <NUM>, processing circuitry <NUM> may be configured to communicate with network 243b using communication subsystem <NUM>.

<FIG> illustrates an example virtualization environment <NUM> in which functions implemented by some embodiments may be virtualized.

<FIG> illustrates a telecommunications network connected via an intermediate network to a host computer in accordance with some embodiments.

<FIG> illustrates a host computer communicating via a base station with a user equipment over a partially wireless connection in accordance with some embodiments.

Wireless connection <NUM> between UE <NUM> and base station <NUM> is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to UE <NUM> using OTT connection <NUM>, in which wireless connection <NUM> forms the last segment. More precisely, the teachings of these embodiments may improve RRC signaling by minimizing or avoiding the RRC signaling due to intra-cell mobility. This may provide benefits such as an improved user experience and better usage of wireless resources.

<FIG> illustrates an exemplary method <NUM> by a wireless device <NUM> for optimized reconfiguration of RLM and beam monitoring, in accordance with certain embodiments. The method begins at step <NUM> when the wireless device <NUM> receives, from a first network node <NUM>, a first message comprising at least one RLM parameter. At step <NUM>, the wireless device <NUM> receives, from the first network node <NUM>, a second message indicating activation of at least one RLM parameter associated with the first message. The second message is a lower layer signal compared to the first message.

According to a particular embodiment, the first message is received as a radio resource control, RRC, signal and the second message is received as a medium access control, MAC, control element.

According to a particular embodiment, the at least one RLM parameter includes a first RLM parameter and a second RLM parameter. The first RLM parameter is associated with a first set of reference signal resources, and the second RLM parameter is associated with a second set of reference signal resources. The second set of reference signal resources is different from the first set of reference signal resources.

According to a particular embodiment, each of the first set of reference signal resources and the second set of reference signal resources are less than a number of reference signal resources providing coverage of a cell.

According to a particular embodiment, the method further includes the wireless device <NUM> performing RLM of at least one reference signal resource based on the second message, and the at least one reference signal resource comprises at least one synchronization signal block, SSB, or at least one channel state information-reference signal, CSI-RS.

In a particular embodiment, in response to receiving the second message, the wireless device <NUM> deactivates at least one reference signal resource in the first set of reference signal resources.

In a particular embodiment, in response to receiving the second message, the wireless device <NUM> activates at least one reference signal resource that in not in the first set of reference signal resources.

In a particular embodiment, the first message identifies a reference signal type, and the second message identifies one or more reference signal resources of the reference signal type.

In certain embodiments, the method for optimized reconfiguration of RLM and beam monitoring as described above may be performed by a virtual computing device. <FIG> illustrates an example virtual computing device <NUM> for optimized reconfiguration of RLM and beam monitoring, according to certain embodiments. In certain embodiments, virtual computing device <NUM> may include modules for performing steps similar to those described above with regard to the method illustrated and described in <FIG>. For example, virtual computing device <NUM> may include a first receiving module <NUM>, a second receiving module <NUM>, and any other suitable modules for optimized reconfiguration of RLM and beam monitoring. In some embodiments, one or more of the modules may be implemented using one or more processors <NUM> of <FIG>. In certain embodiments, the functions of two or more of the various modules may be combined into a single module.

The first receiving module <NUM> may perform certain of the receiving functions of virtual computing device <NUM>. For example, in a particular embodiment, first receiving module <NUM> may receive, from a first network node <NUM>, a first message comprising at least one RLM parameter.

The second receiving module <NUM> may perform certain other of the receiving functions of virtual computing device <NUM>. For example, in a particular embodiment, second receiving module <NUM> may receive, from the first network node <NUM>, a second message indicating activation of at least one RLM parameter associated with the first message. The second message is a lower layer signal compared to the first message.

Other embodiments of virtual computing device <NUM> may include additional components beyond those shown in <FIG> that may be responsible for providing certain aspects of the wireless device's functionality, including any of the functionality described above and/or any additional functionality (including any functionality necessary to support the solutions described above). The various different types of wireless devices <NUM> may include components having the same physical hardware but configured (e.g., via programming) to support different radio access technologies, or may represent partly or entirely different physical components.

<FIG> illustrates an exemplary method <NUM> by a network node <NUM> for optimized reconfiguration of RLM and beam monitoring, in accordance with certain embodiments. The method begins at step <NUM> when the network node <NUM> sends, to a wireless device <NUM>, a first message comprising at least one RLM parameter. At step <NUM>, the network node <NUM> sends, to the wireless device <NUM>, a second message indicating activation of at least one RLM parameter associated with the first message. The second message is a lower layer signal compared to the first message.

According to a particular embodiment, the first message is sent as a radio resource control, RRC, signal and the second message is sent as a medium access control, MAC, control element.

According to a particular embodiment, the at least one RLM parameter is associated with at least one synchronization signal block, SSB, or at least one channel state information-reference signal, CSI-RS.

According to a particular embodiment, the second message is sent to the wireless device in response to determining that the wireless device has moved within a cell.

According to a particular embodiment, the first message identifies a reference signal type, and the second message identifies one or more reference signal resources of the reference signal type.

According to a particular embodiment, the at least one RLM parameter comprises a first RLM parameter and a second RLM parameter. The first RLM parameter is associated with a first set of reference signal resources, and the second RLM parameter is associated with a second set of reference signal resources. The second set of reference signal resources is different from the first set of reference signal resources.

In certain embodiments, the method for optimized reconfiguration of RLM and beam monitoring as described above may be performed by a virtual computing device. <FIG> illustrates an example virtual computing device <NUM> for optimized reconfiguration of RLM and beam monitoring, according to certain embodiments. In certain embodiments, virtual computing device <NUM> may include modules for performing steps similar to those described above with regard to the method illustrated and described in <FIG>. For example, virtual computing device <NUM> may include a first sending module <NUM>, a second sending module <NUM>, and any other suitable modules for optimized reconfiguration of RLM and beam monitoring. In some embodiments, one or more of the modules may be implemented using one or more processors <NUM> of <FIG>. In certain embodiments, the functions of two or more of the various modules may be combined into a single module.

The first sending module <NUM> may perform certain of the sending functions of virtual computing device <NUM>. For example, in a particular embodiment, first sending module <NUM> may send, to a wireless device <NUM>, a first message comprising at least one RLM parameter.

The second sending module <NUM> may perform certain other of the sending functions of virtual computing device <NUM>. For example, in a particular embodiment, second sending module <NUM> may send, to the wireless device <NUM>, a second message indicating activation of at least one RLM parameter associated with the first message. The second message is a lower layer signal compared to the first message.

Other embodiments of virtual computing device <NUM> may include additional components beyond those shown in <FIG> that may be responsible for providing certain aspects of the network node's functionality, including any of the functionality described above and/or any additional functionality (including any functionality necessary to support the solutions described above). The various different types of network nodes <NUM> may include components having the same physical hardware but configured (e.g., via programming) to support different radio access technologies, or may represent partly or entirely different physical components.

Claim 1:
A method performed by a wireless device (<NUM>) for optimized reconfiguration of radio link monitoring, RLM, and beam monitoring, the method comprising:
receiving, from a first network node (<NUM>), a first message comprising at least one RLM parameter, wherein the first message is to configure the wireless device with one or more RLM configurations to be activated;
receiving, from the first network node, a second message indicating activation of at least one RLM parameter associated with the first message, wherein the second message is a lower layer signal compared to the first message; and
activating an RLM configuration indicated by the second message.