Filter-based configuration of measurement accuracy

Abstract

There is provided an apparatus comprising at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code configured, with the at least one processor, to cause the apparatus to at least perform: receiving, from a network node, a configuration for reporting information about measurement accuracy of an L1 filter in use; information about the measurement accuracy of the L1 filter having the initial measurement accuracy is transmitted to the network node.

Description

Technical Field

[0001] Various example embodiments relate to measurement accuracy of filters and configuration based on the measurement accuracy. Background Art

[0002] In a cellular communication system, a user equipment may be configured to measure the signal quality of a serving cell and a neighboring cell. The measurement results from such measurements may be used to decide whether it is necessary to handover the user equipment from one cell to another cell. Summary of the invention

[0003] According to some aspects, the subject matter of independent claims is provided. Some example embodiments are defined in the dependent claims. The scope of protection sought by the various example embodiments is specified by the independent claims. The example embodiments and features (if any) described in this specification that do not fall within the scope of the independent claims are to be interpreted as examples that help understand the various example embodiments.

[0004] According to a first aspect, an apparatus is provided, comprising at least one processor; and at least one memory comprising computer program code, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the apparatus to at least perform: receiving a configuration for reporting information about the measurement accuracy of an L1 filter in use from a network node; and sending information about the measurement accuracy of the L1 filter having an initial measurement accuracy to the network node.

[0005] According to a second aspect, a device is provided, comprising at least one processor; and at least one memory comprising computer program code, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the device to at least perform: receive a configuration for autonomous update of an L3 filter, the configuration comprising instructions for updating the L3 filter based on a current measurement accuracy in response to changing an L1 filter having an initial measurement accuracy to another L1 filter having a second measurement accuracy different from the initial measurement accuracy.

[0006] According to a third aspect, a device is provided, comprising at least one processor; and at least one memory comprising computer program code, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the device to at least perform: a) sending a configuration for reporting information about the measurement accuracy of a first filter to a user equipment; and receiving information about the measurement accuracy of an L1 filter with an initial measurement accuracy from the user equipment; or b) sending a receiving configuration for autonomous update of an L3 filter to the user equipment, the configuration comprising instructions for updating the L3 filter based on a current measurement accuracy in response to changing the L1 filter with the initial measurement accuracy to another L1 filter with a second measurement accuracy different from the initial measurement accuracy.

[0007] According to a fourth aspect, a device is provided, comprising at least one processor; and at least one memory comprising computer program code, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the device to at least perform: receiving information about the measurement accuracy of the L1 filter; determining whether to reconfigure the L3 filter based on the following: information about the measurement accuracy of the L1 filter; and the current configuration of the L3 filter; and knowledge of the impact of the measurement accuracy of the L1 filter and the configuration of the L3 filter on the performance of the cascade of the L1 filter and the L3 filter.

[0008] According to a fifth aspect, a method is provided, the method comprising: receiving a configuration for reporting information about a measurement accuracy of an L1 filter in use from a network node; and sending information about the measurement accuracy of the L1 filter with an initial measurement accuracy to the network node.

[0009] According to one embodiment, the L1 filters are filters of the first layer.

[0010] According to one embodiment, the method comprises receiving a reconfiguration of an L3 filter from a network node.

[0011] According to one embodiment, the reconfiguration includes increasing the filter coefficients of the L3 filter; or decreasing the filter coefficients of the L3 filter.

[0012] According to one embodiment, the L3 filter is a filter of the third layer.

[0013] According to one embodiment, the method comprises updating the L3 filter according to the reconfiguration.

[0014] According to one embodiment, the method comprises: changing the L1 filter to another L1 filter having a second measurement accuracy different from the initial measurement accuracy; and sending information about the second measurement accuracy to the network node.

[0015] According to one embodiment, the method comprises: receiving, from a network node, a reconfiguration of an L3 filter that has been updated in response to a change in the measurement accuracy of the L1 filter; and updating the L3 filter according to the reconfiguration.

[0016] According to a sixth aspect, a method is provided, the method comprising: receiving a configuration for autonomous update of an L3 filter, the configuration comprising instructions for updating the L3 filter based on a current measurement accuracy in response to changing an L1 filter having an initial measurement accuracy to another L1 filter having a second measurement accuracy different from the initial measurement accuracy.

[0017] According to one embodiment, the autonomously updated configuration includes a plurality of different filter coefficients of the L3 filter corresponding to different measurement accuracies.

[0018] According to one embodiment, the configuration of the autonomous update includes instructions for scaling the filter coefficients of the L3 filter relative to the current measured accuracy of the L1 filter.

[0019] According to one embodiment, the method includes: changing the L1 filter to another L1 filter having a second measurement accuracy different from an initial measurement accuracy; and updating the L3 filter according to an autonomously updated configuration in response to the changing.

[0020] According to one embodiment, the measurement accuracy of the L1 filter is defined by a measurement accuracy level.

[0021] According to a seventh aspect, a method is provided, comprising: a) sending a configuration for reporting information about a measurement accuracy of a first filter to a user equipment; and receiving information about the measurement accuracy of an L1 filter having an initial measurement accuracy from the user equipment; or b) sending a receiving configuration for autonomous updating of an L3 filter to the user equipment, the configuration comprising instructions for updating the L3 filter based on a current measurement accuracy in response to changing the L1 filter having an initial measurement accuracy to another L1 filter having a second measurement accuracy different from the initial measurement accuracy.

[0022] According to one embodiment, the method comprises after option a): sending information about the measurement accuracy of the L1 filter to another network node (CU).

[0023] According to one embodiment, the method comprises receiving from the network node a configuration for updating the L2 filter configuration based on received information about a measurement accuracy of the L1 filter or based on received information about changing the L1 filter to another L1 filter having a second measurement accuracy different from an initial measurement accuracy.

[0024] According to one embodiment, the method comprises: receiving information from a user equipment about the L1 filter being changed to another L1 filter having a second measurement accuracy different from an initial measurement accuracy; and updating the L2 filter configuration based on the information about the second measurement accuracy.

[0025] According to an eighth aspect, a method is provided, comprising: receiving information about a measurement accuracy of an L1 filter; determining whether to reconfigure an L3 filter based on: information about a measurement accuracy of the L1 filter; and a current configuration of the L3 filter; and knowledge of the impact of the measurement accuracy of the L1 filter and the configuration of the L3 filter on the performance of a cascade of the L1 filter and the L3 filter.

[0026] According to one embodiment, the method includes, in response to determining that the L3 filter is to be reconfigured, reconfiguring the L3 filter and transmitting the reconfiguration of the L3 filter.

[0027] According to one embodiment, the reconfiguration includes increasing the filter coefficients of the L3 filter; or decreasing the filter coefficients of the L3 filter.

[0028] According to another aspect, an apparatus is provided, the apparatus comprising means for performing the method according to the fifth aspect and embodiments thereof.

[0029] According to another aspect, there is provided an apparatus comprising means for performing the method according to the sixth aspect and embodiments thereof.

[0030] According to another aspect, there is provided an apparatus comprising means for performing the method according to the seventh aspect and embodiments thereof.

[0031] According to another aspect, an apparatus is provided, the apparatus comprising means for performing the method according to the eighth aspect and embodiments thereof.

[0032] According to one embodiment, the component includes at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause execution of the apparatus.

[0033] According to another aspect, a computer-readable medium is provided, which includes program instructions, which, when executed by at least one processor, cause an apparatus to at least perform a method according to the fifth aspect and embodiments thereof.

[0034] According to another aspect, a computer-readable medium is provided, which includes program instructions, which, when executed by at least one processor, cause an apparatus to at least perform a method according to the sixth aspect and embodiments thereof.

[0035] According to another aspect, a computer-readable medium is provided, which includes program instructions, which, when executed by at least one processor, cause an apparatus to perform at least the method according to the seventh aspect and its embodiments.

[0036] According to another aspect, a computer-readable medium is provided, which includes program instructions, which, when executed by at least one processor, cause an apparatus to at least perform a method according to the eighth aspect and embodiments thereof.

[0037] According to another aspect, a computer program is provided, which is configured to, when executed on a computer, cause an apparatus to perform the method according to the fifth aspect and its embodiments.

[0038] According to another aspect, a computer program is provided, which is configured to, when executed on a computer, cause an apparatus to perform a method according to the sixth aspect and its embodiments.

[0039] According to another aspect, a computer program is provided, which is configured to, when executed on a computer, cause an apparatus to perform a method according to the seventh aspect and its embodiments.

[0040] According to another aspect, a computer program is provided, which is configured to, when executed on a computer, cause an apparatus to perform a method according to the eighth aspect and its embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The network architecture of a communication system is shown by way of example;

[0042] Figure 2 The measurement model of the user equipment is shown by way of example;

[0043] Figure 3 The precision delay impact and trade-offs of cascaded L1 and L3 filter configurations are shown by way of example;

[0044] Figure 4a A flow chart of a method is shown by way of example;

[0045] Figure 4b A flow chart of a method is shown by way of example;

[0046] Figure 5 The measurement accuracy requirements for the layer 1 filter are shown by way of example;

[0047] Figure 6 The signaling between entities is shown by way of example;

[0048] Figure 7 A block diagram of the apparatus is shown by way of example;

[0049] Figure 8a A flow chart of a method is shown by way of example;

[0050] Figure 8b A flow chart showing a method by way of example; and

[0051] Fig. 9 A flow chart of a method is shown by way of example. DETAILED DESCRIPTION

[0052] When considering measurements performed by a user equipment, there may be a trade-off between the accuracy of the measurements and the delay of the measurements. The user equipment may be configured to send information about the measurement accuracy of the filters of the first layer to the network. This enables the network to decide whether to reconfigure the filters of the third layer. A method for reducing the frequency of mobility failures caused by unnecessary delayed measurements or extremely inaccurate measurements is provided herein.

[0053] Figure 1 The network architecture of a communication system is shown by way of example. In the following, different example embodiments will be described using a radio access architecture based on Advanced Long Term Evolution (LTE-Advanced, LTE-A) or New Radio (NR), also known as the fifth generation (5G), as an example of an access architecture to which the embodiments may be applied, without limiting the embodiments to such an architecture. It is clear to those skilled in the art that, by appropriately adjusting the parameters and processes, the embodiments may also be applied to other types of communication networks with appropriate means. Some examples of other options for suitable systems are Universal Mobile Telecommunications System (UMTS) Radio Access Network (UTRAN or E-UTRAN), Long Term Evolution (LTE, same as E-UTRA), Wireless Local Area Network (WLAN or WiFi), Worldwide Interoperability for Microwave Access (WiMAX), Personal Communications Service (PCS), Wideband Code Division Multiple Access (WCDMA), systems using Ultra-Wideband (UWB) technology, sensor networks, mobile ad hoc networks (MANETs), and Internet Protocol Multimedia Subsystem (IMS), or any combination thereof.

[0054] Figure 1 The example of FIG. 1 shows a portion of an example radio access network. Figure 1User equipment 100 and 102 are shown, which are configured to be in wireless connection with an access node or network node (such as a gNB (i.e., next generation NodeB) or eNB (i.e., evolved NodeB (eNodeB))) 104 providing the cell on one or more communication channels in the cell. In some embodiments, the access node 104 may be an access point of a non-cellular system. The physical link from the user equipment to the network node 104 is called an uplink (UL) or reverse link, while the physical link from the network node 104 to the user equipment is called a downlink (DL) or forward link. It should be understood that the network node or its functions can be implemented using any node, host, server, or access point entity suitable for such use. A communication system typically includes more than one network node, in which case the network nodes may also be configured to communicate with each other via wired or wireless links designed for this purpose. These links may be used for signaling purposes. A network node is a computing device configured to control the radio resources of the communication system to which it is coupled. A network node may also be referred to as a base station (BS), an access point, or any other type of interface device, including a relay station capable of operating in a wireless environment. The network node includes or is coupled to a transceiver. From the transceiver of the network node, a connection is provided to an antenna unit, which establishes a bidirectional radio link to a user equipment. The antenna unit may include multiple antennas or antenna elements. The network node is further connected to a core network 110 (CN or next generation core NGC). According to the system, the other party on the CN side may be a serving gateway (S-GW, routing and forwarding user data packets), a packet data network gateway (P-GW) for providing a user equipment (UE) to connect to an external packet data network, or a mobile management entity (MME), etc. An example of a network node configured to operate as a relay station is an integrated access and backhaul node (IAB). The distributed unit (DU) portion of the IAB node performs the BS function of the IAB node, while the backhaul connection is performed by the mobile terminal (MT) portion of the IAB node. The UE function may be performed by the IAB MT, and the BS function may be performed by the IAB DU. The network architecture may include a parent node, i.e., an IAB donor, which may have a wired connection to the CN and a wireless connection to the IAB MT.

[0055] User device or user equipment (UE) generally refers to a portable computing device, such as a wireless mobile communication device that operates with or without a subscriber identity module (SIM), including but not limited to the following types of devices: mobile stations (mobile phones), smart phones, personal digital assistants (PDAs), cell phones, devices using wireless modems (alarm or measurement devices, etc.), laptop computers and / or touch screen computers, tablet computers, game consoles, notebook computers, networked car connection modules, and multimedia devices. It should be understood that user devices can also be almost exclusively uplink-only devices, an example of which is a camera or video camera that loads images or video clips to a network. User devices can also be devices with the ability to operate in an Internet of Things (IoT) network, which is a scenario in which objects are provided with the ability to transmit data over a network without the need for human-to-human or human-to-computer interaction.

[0056] Furthermore, although these devices are described as a single entity, different units, processors and / or memory units ( Figure 1 (not all shown) may be implemented within these devices to enable their functionality.

[0057] 5G enables the use of Multiple Input Multiple Output (MIMO) technology both on the UE side and on the gNB side, many more base stations or nodes than LTE (the so-called small cell concept), including macro sites operating in cooperation with smaller sites, and the adoption of various radio technologies depending on service requirements, use cases and / or available spectrum. 5G mobile communications support a wide range of use cases and related applications, including video streaming, augmented reality, different ways of sharing data and various forms of machine type applications (such as (massive) machine type communications (mMTC), including vehicle safety, different sensors and real-time control. 5G is expected to have multiple radio interfaces, namely sub-7 GHz, cmWave and mmWave, and may also be integrated with existing legacy radio access technologies (such as LTE). The frequency range below 7 GHz may be referred to as FR1, while the frequency range above 24 GHz (or more precisely, 24-52.6 GHz) is referred to as FR2. At least in the early stages, the frequency range will be similar to that of LTE. The integration can be implemented as a system where macro coverage is provided by LTE and 5G radio interface access comes from small cells by aggregation to LTE. In other words, 5G plans to support both inter-RAT operability (such as LTE-5G) and inter-RI operability (inter-radio interface operability, such as sub-7GHz-cmWave, sub-7GHz-cmWave-mmWave). One of the concepts considered to be used in 5G networks is network slicing, in which multiple independent and dedicated virtual subnets (network instances) can be created within the same infrastructure to run services with different requirements for latency, reliability, throughput, and mobility.

[0058] The communication system may also be capable of communicating with other networks, such as the public switched telephone network or the Internet 112, or utilizing services provided by them. The communication network may also support the use of cloud services, for example, at least a portion of the core network operations may be performed as a cloud service (this is in the Figure 1 114). The communication system may also include a central control entity or the like to provide facilities for the networks of different operators to cooperate, for example in spectrum sharing.

[0059] Edge cloud can be introduced into the radio access network (RAN) by utilizing network function virtualization (NVF) and software defined networking (SDN). Using edge cloud can mean that access node operations are at least partially performed in a server, host or node that is operably coupled to a remote radio head or base station including radio components. Node operations can also be distributed among multiple servers, nodes or hosts. The application of cloud RAN architecture enables RAN real-time functions to be performed on the RAN side (in distributed units DU 104) and non-real-time functions to be performed in a centralized manner (in centralized units CU 108).

[0060] 5G can also make use of satellite communications to enhance or supplement the coverage of 5G services, for example by providing backhaul. Possible use cases are to provide service continuity for machine-to-machine (M2M) or Internet of Things (IoT) devices or on-board passengers, or to ensure service availability for critical communications and future rail / maritime / aeronautical communications. Satellite communications can make use of geostationary orbit (GEO) satellite systems, as well as low-Earth orbit satellite systems, in particular mega-constellations (systems in which hundreds of (nano) satellites are deployed). Each satellite 106 in the constellation can cover several satellite-enabled network entities that create a ground cell. The ground cell can be created by a ground relay node 104 or by a gNB located on the ground or in a satellite.

[0061] UE 100 is connected to the network via a cell controlled by network node 104 that provides good link quality. For example, if the signal to interference plus noise ratio (SINR) of the link is above a certain threshold, the link quality may be considered good. If the UE moves toward the edge of the serving cell, for example by moving further away from the network node 104 controlling the serving cell, and approaches a neighboring cell, the received signal power of the serving cell may decrease, and interference from the neighboring cell may increase. Ultimately, UE 100 switches to a neighboring cell or a target cell to maintain connection with the network.

[0062] UE 100, 102 measures the quality of the serving cell and neighboring cells. UE measurements are used to decide on handover of the UE from one cell to another. Such a handover can be a hard handover, in which the connection is handed over to the new cell; such a handover can also be a soft handover, in which the connection to the new cell is added without giving up the connection to the earlier cell. For example, the reference signal received power (RSRP) of the serving cell can be compared with the RSRP of the target cell to determine whether the UE's connection needs to be handed over from the serving cell to another cell. Due to channel conditions or hardware impairments, such as thermal noise, fast fading, measurement errors, and shadow fading, received signal power measurements may fluctuate greatly. Due to the rapid fluctuations and uncertainties of the measurement signals, using these measurements without any filtering may lead to suboptimal or inefficient decisions. Inaccurate cell quality measurements can lead to incorrect handover decisions in the network and cause the UE to experience service interruptions, such as radio link failure (RLF), handover failure (HOF) or ping-pong (PP), repeated handovers.

[0063] To mitigate these impairments and uncertainties, thereby preventing erroneous decisions, these raw measurements are filtered. For example, filtering can include filtering through a moving average filter (i.e., a layer 1 (L1) filter) and a recursive filter (i.e., a layer 3 (L3) filter), which provide smoother and more accurate measurements at the expense of additional delays in the measurements due to filtering.

[0064] Figure 2 The measurement model of the user equipment is shown by way of example. Section 9.2.4 of the Third Generation Partnership Project (3GPP) Technical Specification (TS) 38.300 defines a measurement model for a UE in radio resource control (RRC) connected mode. Here, the UE measures at least one beam 201, 201, 203 of a cell (e.g., a cell controlled by a gNB). In the case of multiple beams, the measurement results (e.g., power values) may be averaged to derive the cell quality. In this way, the UE is configured to consider a subset of the detected beams.

[0065] The filtering occurs at two different levels: at the physical layer (L1), beam quality is derived, and then at the RRC level (L3), cell quality is derived from multiple beams. Cell quality can be derived from beam measurements in the same way for both serving cell(s) and non-serving cell(s).

[0066] Beams 201, 202, 203 are measurements used to obtain beam specific samples. The measurements are internal to the physical layer.

[0067] Inside Layer 1 (L1), filtering 210 filters the measurements of beams 201, 202, 203. Filtering 210 includes measurement averaging and is UE implementation specific.

[0068] The beam specific measurements 212 reported by L1 filtering are input to Layer 3 (L3). Parameters 214 for beam combining or selection may be configured via RRC signaling. The beam specific measurements are combined to derive cell quality 216.

[0069] The cell quality 216 is filtered by L3 filtering 218, for which parameters may be configured via RRC signaling.

[0070] The L3 filter 218 is a recursive filter, such as the filter defined in 3GPP TS 38.331 Section 5.5.3.2, which is represented as

[0071] F n =(1-a)×F n -1+a×M n .

[0072] Here, Fn is the current L3 filter output ( Figure 2 220), F n-1 is the previous L3 filter output, M n is the current L3 filter input ( Figure 2 216). a is the forgetting factor of the recursive filter, which is defined as k is the filter coefficient configured by the network to determine the time characteristics of the L3 filter. The filter is adapted so that the time characteristics of the filter are maintained at different input rates, observing that the filter coefficient k assumes a sampling rate equal to X ms. The value of X is equal to one intra-frequency L1 measurement period.

[0073] The output 220 from the L3 filtering is used as input to the evaluation 222 of the reporting criteria.

[0074] Evaluation 222 of the reporting criteria may be configured via RRC signaling. For example, the UE may evaluate the reporting criteria at least every time a new measurement result is reported.

[0075] The output 224 of the evaluation is a measurement report.The measurement report 224 is sent out over the radio interface.

[0076] Parameters for L3 beam filtering 230 and for reported beam selection 232 may be configured via RRC signaling. The selected beam is reported in a measurement report 234 sent out over the radio interface.

[0077] How and when the UE performs L1 filtering 210 is implementation specific that the output 216 (i.e., cell quality) meets the performance requirements set in TS38.133. The L1 synchronization signal block reference signal received power (SSB-RSRP) intra-frequency measurement requirements are defined in FR2 as absolute accuracy and relative accuracy. The defined accuracy requirements set a lower limit for the L1 implementation accuracy. The UE's L1 filter implementation can provide better accuracy than required. However, there is a trade-off between accuracy and the delay caused by the measurement. More accurate L1 measurements can result in delays in the measurement because a large number of samples need to be averaged over time. Fast L1 measurements can result in inaccurate measurements because a small number of samples need to be averaged over time.

[0078] The same trade-off exists for L3 filtering that is configured and controlled by the network. Configuring the L3 filter time constant k to a larger value means configuring the L3 filter forgetting factor a to a smaller value, which makes the L3 filter measurements smoother or less volatile and accurate, but at the expense of increased latency. The latency depends on the previous measurements in memory, as the memory factor (1-a) becomes larger.

[0079] L3 measurement( Figure 2220) is used by the UE to evaluate the measurement reporting criteria and possibly initiate a handover procedure. The measurement and filtering are cascaded so that the physical layer raw measurements 201, 202, 203 are first filtered by the L1 filter 210, and then the output of the L1 filter is further filtered by the L3 filter 218. Therefore, the accuracy and delay introduced by both the L1 filter and the L3 filter are also cascaded.

[0080] The L1 filter may be referred to as the first filter or the filter of the first layer. For example, the first layer is the physical layer of the 5G protocol stack. The L3 filter may be referred to as the third filter or the filter of the third layer. The third layer may be the RRC layer. In the context of low layer mobility (LLM), the L2 filter may be referred to as the second filter or the filter of the second layer. The second layer may be the media access control (MAC) sublayer.

[0081] Figure 3 The precision delay impact and tradeoffs of the cascaded L1 and L3 filter configuration are shown by way of example. The x-axis 310 shows the L3 filter coefficient k, and the y-axis 320 shows the number of L1 samples averaged over time. Regions 330, 340 show reasonable operating regions where measurements have medium precision and medium delay. Region 330 is characterized by a large number of averaged L1 samples and a small L3 filter coefficient k. Region 340 is characterized by a small number of averaged L1 samples and a large L3 filter coefficient k.

[0082] Regions 335, 345 show regions of unreasonable operation. Region 335 is characterized by a large number of averaged L1 samples and a large L3 filter coefficient k. This configuration results in high precision and large delay. Region 345 is characterized by a small number of averaged L1 samples and a small L3 filter coefficient k. This configuration results in low precision and short delay.

[0083] As mentioned above, the lower limit of the L1 implementation accuracy on the UE side has been set, but the UE can implement the L1 filter with higher accuracy. However, even if the network knows the limits defined in the specification, the network does not know the accuracy of the L1 filter implementation and the degree of delay measured by the L1 filter.

[0084] For example, let us assume that the network is configured with a large L3 filter coefficient k. Large L3 filter coefficients result in an accurate L3 filter, but at the expense of delayed measurements. If the L1 filter measurements are inaccurate (although they meet the accuracy requirements of Tables 1 and 2, the L1 filter may be operating at the minimum requirements), the cascaded L1 and L3 filter measurements will be reasonably (not too much) delayed and accurate due to the L3 filter configuration. However, the network does not know how accurate the L1 filter implementation is, and the network has configured the L3 filter with large filter coefficients to be on the safe side. If the L1 filter implementation is also accurate, and on average results in a delay in the L1 filter measurements, then cascading the L1 and L3 filters will result in unnecessarily accurate measurements and excessively delayed measurements. This example situation is caused by Figure 3 Area 335 in the description.

[0085] As another example, the network may configure a smaller L3 filter coefficient k, which results in the L3 filter measurement being less accurate for a delay-free measurement. If the UE's L1 filter implementation is designed in a way that produces accurate measurements (beyond the accuracy defined in Tables 1 and 2), then the cascaded L1 and L3 filter structure will result in reasonably accurate and delayed measurements. However, it is also possible that the UE's L1 filter may produce inaccurate and delay-free measurements, for example, by operating at the minimum accuracy requirements defined in the specification. This example case results in the cascaded L1 and L3 filter measurement results being unreliable due to extremely inaccurate measurements. This example case is caused by Figure 3 Area 345 in the description.

[0086] Therefore, the accuracy and degree of delay of the L1 filter measurements are not transparent to the network, since the L1 filtering is specific to the UE implementation. A mismatch may occur between the L1 filter design and the L3 filter configuration. In some cases, this may result in, for example, unnecessarily accurate and extremely delayed L3 measurements, increasing the risk of delayed handover decisions and failures. As another example, the network is not aware that the L1 filtering implementation may result in unreliable and very fast L3 measurements, which increases the risk of unnecessary handovers, such as Ping-Pong (PP) or Short-Stay (SS).

[0087] Methods and apparatus configured to perform these methods are provided for coordinating L1 filter properties and L3 filter configuration of a UE L1 filter implementation.The properties of the filter include, for example, the accuracy and, thereby, the delay of the filter.

[0088] Figure 4a The flowchart of the method 400 is shown by way of example. The method may be performed by a user equipment or by a control device configured to control its functions when installed therein. The UE may be, for example, Figure 6The device 610 is configured to perform at least the method 400. The method 400 includes receiving 410 a configuration for reporting information about the measurement accuracy of the L1 filter in use from a network node. The method 400 includes sending 420 information about the measurement accuracy of the L1 filter with an initial measurement accuracy to the network node.

[0089] Figure 4b A flow chart of method 450 is shown by way of example. The method may be performed by a user equipment or by a control device configured to control its functions when installed therein. The UE may be, for example, Figure 6 The device 610 is configured to perform at least the method 450. The method 450 includes receiving 460 a configuration for autonomous updating of the L3 filter, the configuration including instructions for updating the L3 filter based on a current measurement accuracy in response to changing the L1 filter having an initial measurement accuracy to another L1 filter having a second measurement accuracy different from the initial measurement accuracy.

[0090] For example, information about measurement accuracy can be given using different measurement accuracy levels (MA levels). A mapping can be defined between different levels of measurement accuracy and MA levels. MA levels can define different levels of accuracy requirements to be met by UEs, which claim that they can meet the MA level requirements. MA levels can be mapped to accuracy requirements defined in 3GPP TS 38.133. For example, a default MA level can define the minimum requirements that a UE can provide. UEs that can provide better measurement accuracy than the minimum requirements can be tested, which proves that the UE can provide better accuracy than the default MA level.

[0091] For example, an additional column may be added to the measurement accuracy requirement table of TS 38.133. The title of the additional column may be "Accuracy Level" or "MA Level", etc. The rows in the MA Level column identify different levels of MA levels, which require the UE L1 filter implementation to meet different measurement accuracy. Figure 5 The measurement accuracy requirements for the Tier 1 filter are shown by way of example.

[0092] Reporting information about the measurement accuracy (e.g., using MA level) enables the UE to provide the network with more fine-grained information about the measurement accuracy of the L1 filter currently in use. The method disclosed herein enables the UE to provide information about the accuracy level (and thus also the latency) of the L1 filtering to the network without having to reveal any L1 filter implementation details. Therefore, the network can use this information to configure the L3 filter or the L2 filter in coordination with the L1 filter characteristics. The configuration of the L3 filter involves L3 mobility, and the configuration of the L2 filter involves low layer mobility (LLM). As Figure 3As shown in the regions 335 and 345 in FIG. 3 , the method disclosed herein enables the network to avoid operating in undesirable regions. Finally, the method disclosed herein enables the network to prevent mobility failures caused by unnecessary delay measurements or ping-ponging and short stays caused by extremely inaccurate measurements.

[0093] Reference again Figure 5 , the example table 500 shows three MA levels in the MA level column 510. It should be noted that the MA levels shown are illustrative, i.e., there may be less than three MA levels, such as only two MA levels; or there may be more than three MA levels. In addition, the accuracy margin of each level under normal and extreme conditions may be different from Figure 5 The example table of FIG. 1 is different from that shown in FIG. 1. MA level 1 can be regarded as a default level. That is, the default level can be based on the minimum L1 filter measurement accuracy requirement.

[0094] For example, multiple MA levels may be defined such that higher MA levels require tighter measurement accuracy margins than lower levels. For example, if there are more than one MA level, such as three MA levels are defined, the accuracy margin ±σ2 of MA level 2 may be defined as less than the accuracy margin ±σ1 (±6dB) of MA level 1. That is, σ2<σ1, where σ1, σ2>0. Similarly, the accuracy margin of MA level 3 may be defined as less than the accuracy margin of MA level 2. That is, σ3<σ2, where σ2, σ3>0.

[0095] Will be in Figure 6 The method of FIG. 4 and its embodiments are described in more detail in the context of FIG.

[0096] Figure 6 Signaling between entities is shown by way of example. A UE 610 is currently served by a network node (e.g., a gNB) that includes a source distributed unit (DU) 620. The UE may be handed over from the source DU 620 to another network node, such as a gNB, that includes a target DU 640. A centralized unit (CU) 630 is configured, for example, to coordinate RRC and handover decision processes.

[0097] The UE 610 connects 650 to the source DU 620. The UE receives 650 RRC related configurations from the network, such as measurement configurations, mobility parameters and L3 filter configurations.

[0098] The UE 610 receives 650 from the network node a configuration for reporting information about the measurement accuracy of the first filter (e.g., the L1 filter). For example, once the UE 610 is RRC connected, the network configures the UE 610 to report information about the measurement accuracy of the L1 filter (e.g., defined by the MA level) to the source DU 620. Therefore, the UE is configured to report the initial MA level of the L1 filter in use by the UE 610.

[0099] The UE is configured to report information about the measurement accuracy of the L1 filter to the source DU 620 in response to the update of the MA level. For example, if the UE starts using a different L1 filter than the filter used initially (which meets different MA level requirements), the UE is configured to report the update of the MA level to the network.

[0100] The UE 610 decides 651 to use an L1 filter that meets the accuracy requirement of MA level 2. In other words, the UE decides to use a first filter with an initial measurement accuracy or a first measurement accuracy. For example, the initial measurement accuracy may be defined by MA level 2.

[0101] The UE 610 transmits 652 the initial MA level of the L1 filter in use to the network. In other words, the UE transmits information on the measurement accuracy of the first filter with the initial measurement accuracy.

[0102] The source DU 620 receives information about the measurement accuracy of the first filter from the UE 610 and transmits 653 or relays the information to another network node (eg, the CU 630).

[0103] The CU 630 receives information about the measurement accuracy of the first filter. The CU 630 is configured to determine 654 whether to reconfigure the L3 filter of the UE 610. For example, the CU is configured to analyze the information about the measurement accuracy of the first filter and the current configuration of the L3 filter to determine whether the current configuration results in an undesirable operating state. An undesirable operating state refers to Figure 3 Regions 335 and 345 are shown. In deciding whether to reconfigure the L3 filter, the CU uses the measured accuracy of the L1 filter and the knowledge of the impact of the configuration of the L3 filter on the performance of the cascade of the L1 and L3 filters.

[0104] In response to determining that the L3 filter is to be reconfigured, the CU 630 reconfigures the L3 filter and sends 655 the reconfiguration to the DU 620. For example, the CU 630 may decide to increase the filter coefficient k of the L3 filter in order to improve the accuracy of the filter with a reasonable delay. As another example, the CU 630 decides to decrease the filter coefficient k of the L3 filter to mitigate the delay of the measurement and avoid unnecessarily accurate measurements. Therefore, the reconfiguration may include the updated filter coefficients of the L3 filter. For example, the updated filter coefficients may be greater than the previous filter coefficients.

[0105] The DU 620 sends 656 or relays the reconfiguration of the L3 filter to the UE 610 .

[0106] The UE 610 receives 656 the reconfiguration of the L3 filter, applies the new reconfiguration and updates the L3 filter. The UE 610 may send 657 a confirmation of the update to the network.

[0107] The UE 610 may decide to change 658 the L1 filter in use to another L1 filter implementation. In other words, the UE may change the L1 filter with the initial measurement accuracy to another L1 filter with a second measurement accuracy different from the initial measurement accuracy. For example, the UE 610 may start using an L1 filter that satisfies a higher MA level than the L1 filter currently in use. For example, the MA level of the L1 filter may be changed from 2 to 3.

[0108] The UE 610 sends 659 information about the second measurement accuracy to the source DU 620. For example, when it is configured 650 by the network, the UE reports the updated MA level, for example, MA level 3, to the DU 620.

[0109] The source DU 620 receives 659 information about the updated measurement accuracy of the L1 filter from the UE 610 , and sends 660 or relays the information to the CU 630 .

[0110] The CU 630 receives information about the updated measured accuracy of the L1 filter. As described above, in 654 , the CU 630 is configured to determine whether to reconfigure the L3 filter.

[0111] In response to determining that the L3 filter is to be reconfigured, the CU 630 reconfigures the L3 filter and sends 662 the reconfiguration to the DU 620. The reconfiguration may include updated filter coefficients for the L3 filter. For example, the updated filter coefficients may be smaller than the previous filter coefficients.

[0112] The DU 620 sends 663 or relays the reconfiguration of the L3 filter to the UE 610 .

[0113] The UE 610 receives 663 the reconfiguration of the L3 filter, applies the new reconfiguration and updates the L3 filter. The UE 610 may send 664 a confirmation of the update to the network.

[0114] When the measurement report triggering condition is met on the UE side, the UE issues 665 a measurement report to initiate a low layer mobility (LLM) procedure. The DU 620 relays 666 the report to the CU 630, which prepares the target DU 640 by sending 667 a UE context setup request to the target DU 640.

[0115] The target DU 640 responds by sending 668 a UE Context Setup Response to the CU 630 .

[0116] Once the target DU 640 is ready, the CU 630 generates a new RRC reconfiguration to be applied to the UE side during LLM. The CU sends 669 the reconfiguration to the DU 620, which relays 670 the reconfiguration to the UE 610. The UE is configured to measure the target signal and report periodic L1 beam measurements of both (multiple) serving and non-serving cells. In addition, the UE is configured to report information about measurement accuracy (e.g., MA level), as well as L1 beam measurements. For example, the UE can be configured to report the MA level when the UE starts using different L1 filters that meet different accuracy requirements. For example, if the MA level is updated or changed, the UE reports the updated MA level together with the L1 beam measurement.

[0117] If the DU 620 receives an update of the MA level from the UE 610, the network configures 669 the DU 620 to update the L2 filter configuration for the different MA levels.

[0118] Therefore, information on the measurement accuracy of the L1 filter, such as MA level information, may be used during LLM. When the UE 610 reports the MA level information to the DU 620, the DU 620 updates the L2 filter configuration accordingly.

[0119] The DU 620 transmits 670 a reconfiguration to the UE 610. The reconfiguration includes a configuration for reporting information on measurement accuracy together with L1 beam measurement if the measurement accuracy is updated.

[0120] The UE 610 may send 671 a confirmation of the reconfiguration to the network.

[0121] The UE starts reporting 672 L1 beam measurements. Since there is no update of the MA level, the UE does not necessarily include the MA level information in the measurement report.

[0122] The UE changes the measurement accuracy of the L1 filter from MA level 3 to MA level 2, for example.

[0123] The UE reports 674 the L1 beam measurements and information about the updated measurement accuracy, such as information about the MA level change. For example, according to the received 670 reconfiguration, the UE may include the new MA level in the reported L1 beam measurements.

[0124] The DU receives the measurement report and updated measurement accuracy information and may update the L2 filter configuration, as shown in configuration 669 .

[0125] The UE may continue with measurement reporting 675. The source DU 620 may trigger 676 a cell change. The UE will switch 677 from the source DU 620 to the target DU 640.

[0126] According to one embodiment, the network may configure 650 an autonomous update of the L3 filter configuration to the UE 610. For example, the autonomously updated configuration may define L3 filter coefficients for different MA levels. In other words, there may be a mapping between the filter coefficients and the MA level. Whenever the UE updates the MA level, the UE may autonomously update the L3 filter according to the configuration.

[0127] As another example, the network may configure the UE to scale the L3 filter coefficients relative to the MA level of the UE L1 filter currently in use. For example, if the current filter coefficient is k, and the current MA level is 1. Then, if the updated MA level is 2, the UE may scale the filter coefficients by a scaling factor of 1 / 2 according to the configuration to set k to k / 2. If the MA level is further increased, the L3 filter coefficients are further scaled, either by the same scaling factor of 1 / 2 to set k / 2 to k / 4, or by a different scaling factor of 1 / 3 to set k / 2 to k / 6.

[0128] The autonomously updated configuration enables autonomous updating of the L3 filter configuration in response to changes in the measurement accuracy of the first filter, thereby reducing or avoiding additional signaling between the UE and the network entities CU and DU.

[0129] Figure 7 An apparatus capable of performing the methods disclosed herein is shown by way of example. The illustrated apparatus 700 may include, for example, a mobile communication device such as Figure 6 A mobile device or UE 610 or Figure 6The network nodes 620, 630 of the present invention are provided. The device 700 includes a processor 710, which may include, for example, a single-core or multi-core processor, wherein the single-core processor includes one processing core and the multi-core processor includes more than one processing core. The processor 710 may generally include a control device. The processor 710 may include more than one processor. The processor 710 may be a control device. The processing core may include, for example, a Cortex-A8 processing core manufactured by ARM Holdings or a Steamroller processing core designed by Advanced Micro Devices Corporation. The processor 710 may include at least one Qualcomm Snapdragon and / or Intel Atom processor. The processor 710 may include at least one application-specific integrated circuit ASIC. The processor 710 may include at least one field programmable gate array FPGA. The processor 710 may be a component for performing method steps in the device 700. The processor 710 may be configured to perform actions at least in part by computer instructions.

[0130] The processor may include circuitry, or be constructed as one or more circuitry, configured to perform the various stages of the method according to the example embodiments described herein. As used in this application, the term "circuitry" may refer to one or more or all of the following: (a) a hardware circuit implementation only, such as an implementation in analog and / or digital circuitry only, and (b) a combination of hardware circuitry and software, such as, where applicable: (i) a combination of (multiple) analog and / or digital hardware circuits with software / firmware, and (ii) any portion of (multiple) hardware processors (including (multiple) digital signal processors), software and (multiple) memories with software, which work together to cause the device (such as a mobile phone, UE or network node) to perform various functions, and (c) (multiple) hardware circuits and / or (multiple) processors, such as (multiple) microprocessors or parts of (multiple) microprocessors, which require software (e.g., firmware) to operate, but when software is not required for operation, the software may not be present.

[0131] This definition of circuitry applies to all uses of the term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of only a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its accompanying software and / or firmware. For example, if applicable to a particular claim element, the term circuitry also covers a baseband integrated circuit or processor integrated circuit for a mobile device, or a similar integrated circuit in a server, cellular network device, or other computing or network device.

[0132] The device 700 may include a memory 720. The memory 720 may include random access memory and / or permanent memory. The memory 720 may include at least one RAM chip. The memory 720 may include, for example, solid-state, magnetic, optical and / or holographic memory. The memory 720 may be at least partially accessible by the processor 710. The memory 720 may be at least partially included in the processor 710. The memory 720 may be a component for storing information. The memory 720 may include computer instructions that the processor 710 is configured to execute. When computer instructions configured to cause the processor 710 to perform certain actions are stored in the memory 720, and the device 700 is generally configured to run under the direction of the processor 710 using computer instructions from the memory 720, the processor 710 and / or at least one of its processing cores may be considered to be configured to perform certain actions described above. The memory 720 may be at least partially external to the device 700, but accessible by the device 700.

[0133] The device 700 may include a transmitter 730. The device 700 may include a receiver 740. The transmitter 730 and the receiver 740 may be configured to transmit and receive information, respectively, according to at least one cellular or non-cellular standard. The transmitter 730 may include more than one transmitter. The receiver 740 may include more than one receiver. The transmitter 730 and / or the receiver 740 may be configured to operate according to standards such as Global System for Mobile Communications GSM, Wideband Code Division Multiple Access WCDMA, 5G, Long Term Evolution LTE, IS-95, Wireless Local Area Network WLAN, Ethernet, and / or Worldwide Interoperability for Microwave Access WiMAX.

[0134] The device 700 may include a near field communication NFC transceiver 750. The NFC transceiver 750 may support at least one NFC technology, such as NFC, Bluetooth, Wibree, or similar technology.

[0135] The device 700 may include a user interface UI 760. The UI 760 may include at least one of a display, a keyboard, a touch screen, a vibrator, a speaker, and a microphone, the vibrator being arranged to signal a user by causing the device 700 to vibrate. The user may be able to operate the device 700 via the UI 760, for example, to accept an incoming phone call, place a phone call or video call, browse the Internet, manage digital files stored in the memory 720 or on the cloud (the cloud is accessible via the transmitter 730 and the receiver 740, or via the NFC transceiver 750), and / or play games.

[0136] The device 700 may include or be arranged to accept a user identity module 770. For example, the user identity module 770 may include a subscriber identity module SIM card installable in the device 700. The user identity module 770 may include information identifying a subscription of a user of the device 700. The user identity module 770 may include cryptographic information that may be used to verify the identity of the user of the device 700 and / or facilitate encryption of transmitted information and billing of the user of the device 700 for communications achieved via the device 700.

[0137] The processor 710 may be equipped with a transmitter that is arranged to output information from the processor 710 to other devices included in the device 700 via electrical leads inside the device 700. Such a transmitter may include a serial bus transmitter that is arranged to output information to the memory 720 for storage therein, for example, via at least one electrical lead. As an alternative to a serial bus, the transmitter may include a parallel bus transmitter. Similarly, the processor 710 may include a receiver that is arranged to receive information in the processor 710 from other devices included in the device 700 via electrical leads inside the device 700. Such a receiver may include a serial bus receiver that is arranged to receive information from the receiver 740, for example, via at least one electrical lead, for processing in the processor 710. As an alternative to a serial bus, the receiver may include a parallel bus receiver.

[0138] The processor 710, the memory 720, the transmitter 730, the receiver 740, the NFC transceiver 750, the UI 760 and / or the user identity module 770 may be interconnected in a variety of different ways via electrical leads inside the device 700. For example, each of the above devices may be connected to a main bus inside the device 700, respectively, to allow the devices to exchange information. However, as will be appreciated by those skilled in the art, this is merely an example, and various ways of interconnecting at least two of the above devices may be selected according to the embodiment.

[0139] Figure 8a A flow chart of a method is shown by way of example. The method 800 may be performed by a network node or by a control device configured to control its functions when installed therein. The network node may be a source DU or a source gNB-DU, e.g. Figure 6 The device 620 is configured to perform at least the method 800. The method 800 includes sending 810 a configuration for reporting information about the measurement accuracy of the first filter to the user equipment. The method 800 includes receiving 820 information about the measurement accuracy of the L1 filter with the initial measurement accuracy from the user equipment.

[0140] Figure 8bA flow chart of a method is shown by way of example. The method 850 may be performed by a network node or by a control device configured to control its functions when installed therein. The network node may be a source DU or a source gNB-DU, e.g. Figure 6 The device 620 is configured to perform at least the method 850. The method 850 includes sending 860 to the user equipment a reception configuration of autonomous update of the L3 filter, the configuration including instructions for updating the L3 filter based on the current measurement accuracy in response to changing the L1 filter having the initial measurement accuracy to another L1 filter having a second measurement accuracy different from the initial measurement accuracy.

[0141] Fig. 9 A flow chart of a method is shown by way of example. The method 900 may be performed by a network node or by a control device configured to control its functions when installed therein. The network node may be a CU or a gNB-CU, for example Figure 6 The device 620 is configured to perform at least the method 900. The method 900 includes receiving 910 information about the measurement accuracy of the L1 filter. The method 900 includes determining 920 whether to reconfigure the L3 filter based on: the information about the measurement accuracy of the L1 filter; and the current configuration of the L3 filter; and knowledge of the impact of the measurement accuracy of the L1 filter and the configuration of the L3 filter on the performance of the cascade of the L1 filter and the L3 filter.

Claims

1. An apparatus comprising at least one processor; and at least one memory comprising computer program code, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the apparatus to at least perform: receiving, from a network node, a configuration for reporting information about a measurement accuracy of an L1 filter in use; and Information about the measurement accuracy of the L1 filter with an initial measurement accuracy is sent to the network node. The apparatus according to claim 1 , wherein the L1 filter is a filter of a first layer.

3. The apparatus according to claim 1 or 2, further configured to perform: A reconfiguration of an L3 filter is received from the network node.

4. The apparatus of claim 3, wherein the reconfiguration comprises: increasing the filter coefficients of the L3 filter; or The filter coefficients of the L3 filter are reduced. The apparatus according to claim 3 or 4 , wherein the L3 filter is a filter of a third layer.

6. The apparatus according to any one of claims 3 to 5, further configured to perform: The L3 filter is updated according to the reconfiguration.

7. The apparatus according to any one of the preceding claims, further configured to perform: changing the L1 filter to another L1 filter having a second measurement accuracy different from the initial measurement accuracy; and Information about the second measurement accuracy is sent to the network node.

8. The apparatus according to claim 7, further configured to perform: receiving from the network node a reconfiguration of the L3 filter that has been updated in response to a change in the measurement accuracy of the L1 filter; and The L3 filter is updated according to the reconfiguration.

9. An apparatus comprising at least one processor; and at least one memory comprising computer program code, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the apparatus to at least perform: Receiving an autonomously updated configuration of an L3 filter, the configuration comprising: Instructions for updating the L3 filter based on a current measurement precision in response to changing an L1 filter having an initial measurement precision to another L1 filter having a second measurement precision different from the initial measurement precision.

10. The apparatus according to claim 9, wherein the configuration of the autonomous update comprises: A plurality of different filter coefficients of the L3 filter corresponding to different measurement accuracies.

11. The apparatus according to claim 9, wherein the configuration of the autonomous update comprises: Instructions for scaling filter coefficients of the L3 filter relative to the current measured accuracy of the L1 filter.

12. The apparatus according to any one of claims 9 to 11, further configured to: changing the L1 filter to another L1 filter having the second measurement accuracy different from the initial measurement accuracy; and In response to the change, the L3 filter is updated according to the autonomously updated configuration.

13. The device according to any one of the preceding claims, The measurement accuracy of the L1 filter is defined by a measurement accuracy level.

14. An apparatus comprising at least one processor; and at least one memory comprising computer program code, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the apparatus to at least perform: a) sending a configuration for reporting information about a measurement accuracy of a first filter to a user equipment; and receiving, from the user equipment, information on the measurement accuracy of the L1 filter having an initial measurement accuracy; or b) sending a receiving configuration of autonomous update of the L3 filter to the user equipment, the configuration comprising: Instructions for updating the L3 filter based on a current measurement precision in response to changing an L1 filter having an initial measurement precision to another L1 filter having a second measurement precision different from the initial measurement precision.

15. The apparatus according to claim 14, further configured to perform, after option a): Information about the measured accuracy of the L1 filter is sent to another network node (CU).

16. The apparatus according to claim 14 or 15, further configured to perform: A configuration for updating an L2 filter configuration based on the received information about the measurement accuracy of the L1 filter or the received information about changing the L1 filter to another L1 filter having a second measurement accuracy different from the initial measurement accuracy is received from a network node.

17. The apparatus according to claim 16, further configured to perform: receiving, from the user equipment, information about the L1 filter being changed to another L1 filter having the second measurement accuracy different from the initial measurement accuracy; and The L2 filter configuration is updated based on the information about the second measurement accuracy.

18. An apparatus comprising at least one processor; and at least one memory comprising computer program code, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the apparatus to at least perform: receiving information regarding a measured accuracy of an L1 filter; Determines whether to reconfigure the L3 filter based on the following: - said information on the measured accuracy of said L1 filter; and - the current configuration of the L3 filter; as well as - Knowledge of the impact of the measured accuracy of the L1 filter and the configuration of the L3 filter on the performance of the cascade of the L1 filter and the L3 filter.

19. The apparatus according to claim 18, further configured to perform: In response to determining that the L3 filter is to be reconfigured, the L3 filter is reconfigured and the reconfiguration of the L3 filter is transmitted.

20. The apparatus of claim 19, wherein the reconfiguring comprises: increasing the filter coefficients of the L3 filter; or The filter coefficients of the L3 filter are reduced.

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