Patent Description:
A wireless device can sometimes have multiple wireless connections. In some instances, this can be via Carrier Aggregation (CA) or Dual Connectivity (DC). In order for the wireless device to be configured with these connections, appropriate measurements are needed. When these measurements are not yet available, the time to set up the multiple wireless connections is extended. Therefore, improved systems and methods for performing measurements are needed. Measurements in the context of DC or CA are discussed for example in <CIT>, R2-<NUM> (Qualcomm Incorporated) and <CIT>.

Systems and methods for triggering measurements before the completion of connection resumption are provided.

<FIG> illustrates one example of a cellular communications network <NUM> according to some embodiments of the present disclosure. In the embodiments described herein, the cellular communications network <NUM> is a <NUM> NR network. In this example, the cellular communications network <NUM> includes base stations <NUM>-<NUM> and <NUM>-<NUM>, which in LTE are referred to as eNBs and in <NUM> NR are referred to as gNBs, controlling corresponding macro cells <NUM>-<NUM> and <NUM>-<NUM>. The base stations <NUM>-<NUM> and <NUM>-<NUM> are generally referred to herein collectively as base stations <NUM> and individually as base station <NUM>. Likewise, the macro cells <NUM>-<NUM> and <NUM>-<NUM> are generally referred to herein collectively as macro cells <NUM> and individually as macro cell <NUM>. The cellular communications network <NUM> may also include a number of low power nodes <NUM>-<NUM> through <NUM>-<NUM> controlling corresponding small cells <NUM>-<NUM> through <NUM>-<NUM>. The low power nodes <NUM>-<NUM> through <NUM>-<NUM> can be small base stations (such as pico or femto base stations) or Remote Radio Heads (RRHs), or the like. Notably, while not illustrated, one or more of the small cells <NUM>-<NUM> through <NUM>-<NUM> may alternatively be provided by the base stations <NUM>. The low power nodes <NUM>-<NUM> through <NUM>-<NUM> are generally referred to herein collectively as low power nodes <NUM> and individually as low power node <NUM>. Likewise, the small cells <NUM>-<NUM> through <NUM>-<NUM> are generally referred to herein collectively as small cells <NUM> and individually as small cell <NUM>. The base stations <NUM> (and optionally the low power nodes <NUM>) are connected to a core network <NUM>.

As stated earlier, DC is standardized for both LTE and Evolved Universal Terrestrial Radio Access (E-UTRA)-NR DC (EN-DC).

LTE DC and EN-DC are designed differently when it comes to which nodes control what. Basically, there are two options:.

<FIG> shows the schematic control plane architecture for LTE DC and EN-DC. The main difference here is that in EN-DC, the Secondary Node (SN) has a separate RRC entity (NR RRC). This means that the SN can control the UE also; sometimes without the knowledge of the Master Node (MN) but often the SN needs to coordinate with the MN. In LTE-DC, the RRC decisions are always coming from the MN (MN to UE). Note however, the SN still decides the configuration of the SN, since it is only the SN itself that has knowledge of what kind of resources, capabilities etc. the SN have.

Below two different DC specifications and their RRC messages are discussed in more detail.

When the MeNB decides to request a SeNB Addition, the MeNB indicates within a Secondary Cell Group (SCG)-ConfigInfo (see, e.g., <NUM>, p105) the Master Cell Group (MCG) configuration and the entire UE capabilities for UE capability coordination as well as the latest measurement results for the SCG cell(s) requested to be added, see <FIG> which is an overview of the LTE DC configurations. The SN responds an acknowledgement with a SCG-Config and the latest measConfig to the MeNB. If the MeNB accepts the SCG-Config configurations, it sends this to the UE as well as the UE measurement configurations (MeasConfig) in the RRCConnectionReconfiguration message to the UE.

The MeNB cannot change the SCG-Config from the SeNB, just accept or reject. The reason for this is that the MeNB is not fully aware of the available resources and capabilities of the SeNB. Thus, if the MeNB modifies the SCG-Config can lead to the case that the UE utilizes incorrect resources. In practice, the measurement configuration is controlled by the MN. Note also that in LTE-DC centralized solution the UE's measurement report is sent to the MN only.

The second option is to use a decentralized option, which is used by EN-DC. This means that the SN can directly configure the UE with measurement.

In EN-DC, the main reason to have decentralized measurement configurations was latency requirements. Thus, by supporting a special Signaling Radio Bearer (SRB) (called SRB3) for the SN node (NR) which allows the SN to configure the measurement separately (without involving the MN), the SN can speed up the measurements and measurement configurations. The thinking here is that SRB3 (using NR radio) may allow faster transmission than the corresponding LTE SRBs. Also, the backhaul link between MN and SN may be congested which could negatively affect both the measurement reporting and new measurement configurations.

Thus, sending the UE measurement report directly to the concerned node (MN or SN) can speed up the necessary action (e.g., switch node/add node). Another reason to have decentralized measurements is that LTE and NR use slightly different RRC and different mobility, which also makes it convenient to split the responsibility.

The decentralized EN-DC solution option includes measurement capability coordination. According to the latest 3GPP agreement the SN shall inform the MN every time it changes which carrier frequencies the UE shall measure on. The measurement capability coordination is necessary to not exceed the number of carriers the UE can measure (and also for the gap coordination). If MN and SN configure more carriers than the UE can measure on, the UE probably will randomly ignore one or more carriers for measurements. In the worst case, these ignored carriers may be the most important carriers to measure on.

If the SN receives from the MN a new value for the maximum number of frequency layers or reporting configurations, and it has already configured all the allowed measurements or reporting configurations based on the previous maximum values, it releases the required number of measurements or reporting configurations to comply with the new limit.

It has now been explained why it is important to coordinate the measured frequency carriers. But it was also mentioned above that this is used to coordinate the measurement gaps. To understand why it is important to also coordinate the measurement gaps between MN and SN, it needs to be understood how the measurements in EN-DC works in more detail.

EN-DC may use both "LTE frequencies" and very high <NUM> frequencies. 3GPP distinguishes between Frequency Range <NUM> (FR1) and Frequency Range <NUM> (FR2) frequencies. FR1 is below <NUM> and FR2 is above <NUM>. The reason this is done like this is because of different UE capabilities. Some more advanced UEs can receive data on FR1 and measure on FR2 simultaneously (and vice versa) while some cannot measure on FR1 and receive data on FR2 at the same time (and vice versa).

To be able to measure on any frequency (FR1 or FR2) the UE is configured with a so called "gap", i.e., a certain time when UE does not receive any data on this frequency and can focus on measuring on other cells in this frequency range. If UE can receive data on FR1 and measure on FR2 simultaneously (and vice versa), the "gap" is called per-FR gap. If a UE cannot measure on FR1 and receive data on FR2 simultaneously (and vice versa) it is called per-UE gap. The most efficient way is always to configure per-FR gap, because per-UE gap will influence the scheduling of all serving cells and consequently both FR1 and FR2 data will be interrupted then, i.e., all data transmission will be impacted for a short period for per-UE gap measurements.

Radio Access Network (RAN)<NUM> has agreed that network can choose either per-UE gap or per-FR gap for a UE. As said earlier, both MN and SN can configure the UE with measurement gaps. Thus, some gap coordination is needed. This gap coordination is a bit tricky, and perhaps not absolutely necessary to understand for this IvD but for completeness mentioned here.

In general, the MN configures the gap to the UE if the UE is per-UE capable. Thus, the MN needs to know the SN frequencies in order to calculate a suitable gap also for the SN, and then send this gap configuration to the SN. SN can send the FR1/FR2 frequencies to MN via CG-Config.

If the UE is capable of per FR1/FR2 gaps, it is decided that the MN configures the FR1 gaps and the SN configures the FR2 gaps. However, for the per FR1/FR2 gap case, the MN and SN need to coordinate the gaps, so they don't overlap.

For either per-UE gap or per-LTE/FR1 gap, MN transmits the gap pattern to SN via CG-ConfigInfo (CG-ConfigInfo is the NR name of the SCG-Config in LTE).

An overview of the above EN-DC measurement configurations is given in <FIG>. Note that an important difference compared to LTE-DC is that since the SN also can configure the UE's measurements, these are also transmitted to the SN via the SRB3 (if configured). The SN then directly acts upon these measurements; the MN never receives these measurements (at least there is no specification that supports this by default). If SRB3 is not configured, the measurement configurations from the SN (and the measurement reports from the UE based on these measurement configurations) are sent to the UE (and the measurement results to the SN) via embedded RRC messages from/to the MN on SRB1, which the MN transparently forwards to the UE (the configurations) and the SN (measurement results).

The idea with Multi-Connectivity (MC) is that the UE can connect to more than two nodes, i.e., more than one SN node. The benefits with MC are similar to DC, but MC allows even more new areas to be utilized, e.g., centralized scheduler, even more robust mobility etc..

For a multi-connectivity solution with only one type of radio, e.g., NR base station, some of the above arguments to have a decentralized solution are not as strong anymore since all NR nodes should be equally capable.

From a migration point of view, it is natural to continue using EN-DC principles also for MC, i.e., using a decentralized solution. Also, there may still be cases when a decentralized measurement solution is beneficial, e.g., when the nodes have different capabilities (e.g., <NUM> vs. <NUM> nodes).

In LTE (e.g., Rel-<NUM>), it is possible to configure the UE to report early measurements upon the transition from idle to connected state. These measurements are measurements that the UE has performed in idle state, and according to a configuration provided by the source cell with the intention to receive these measurements and quickly setup DC/CA without the need to first provide a measurement configuration (measConfig) in connected state and wait for hundreds of milliseconds until first samples are collected, monitored and then the first reports are triggered.

A first aspect of the existing solution, as standardized in EUTRA <NUM>, is described in <NUM>. <NUM> Idle Mode Measurements. Therein, the UE is configured upon the transition from RRC_CONNECTED to RRC_IDLE with a dedicated measurement configuration in the RRCConnectionRelease message, highlighted as follows:
<IMG>.

As shown above, a validity timer is also introduced in that configuration. The timer is started upon the reception of the dedicated measurement configuration and stops upon receiving RRCConnectionSetup, RRCConnectionResume or, if validityArea is configured, upon reselecting to cell that does not belong to validityArea. Upon expiry, these measurements performed in idle may be discarded. The intention with validity area is to limit the area where CA/DC may be setup later when the UE resumes/setups the connection, so the early measurements are somewhat useful for that purpose. Notice also that only measurements above a certain thresholds shall be stored as the cell candidates for DC/CA setup needs to be within a minimum acceptable threshold.

How the UE performs measurements in IDLE mode is up to UE implementation as long as RAN4 requirements for measurement reporting defined in <NUM> are met.

The UE behaviour in more details is shown below as captured in <NUM>:.

This procedure specifies the measurements done by a UE in RRC_IDLE when it has an IDLE mode measurement configuration and the storage of the available measurements by a UE in both RRC_IDLE and RRC_CONNECTED.

NOTE: It is up to UE implementation whether to continue IDLE mode measurements according to SIB5 configuration after T331 has expired or stopped.

Another aspect of the existing solution occurs when the UE tries to resume. If the previous step is performed, i.e., if the UE is configured to store idle measurements, the network may request the UE after resume / setup (after security is activated) whether the UE has idle measurements available.

In the case this UE is resuming, the target cell (as long as within the validity area) should be aware of that since the UE Access Stratum (AS) context (After context fetching should contain the latest configurations the UE has received upon entering IDLE). The way the target requests the availability of these stored measurements, is by sending to the UE a UEInformationRequest message, after the UE starts security and enters. This is illustrated in <FIG>.

Reception of the UEInformationRequest message.

Upon receiving the UEInformationRequest message, the UE shall, only after successful security activation:.

In summary, measurements performed in idle may only be provided after security is setup. If the UE is released to IDLE (i.e., no UE context stored), security can be up and running only after security mode command procedure (<NUM> radio RTTs after UE enters RRC_CONNECTED i.e., reception of RRCConnectionSetup), which may take quite some time until the UE reports these measurements and the network can take educated decisions based on these, such as the setup of CA and/or DC.

If the UE is suspended to IDLE (i.e., UE context stored), there is no need for security mode command procedure and security can be up and running upon the reception of RRCConnectionResume, which contains the next hop chaining counter that enables the UE to start security according to target configuration. Then, after the UE enters RRC_CONNECTED the network may send the UEInformationRequest and get the UEInformationResponse with the idle measurements.

3GPP TS <NUM> includes the following:
The network may configure an RRC_CONNECTED UE to perform measurements and report them in accordance with the measurement configuration. The measurement configuration is provided by means of dedicated signaling i.e., using the RRCReconfiguration.

The network may configure the UE to perform the following types of measurements:.

The network may configure the UE to report the following measurement information based on SS/PBCH block(s):.

The network may configure the UE to report the following measurement information based on Channel State Information Reference Signal (CSI-RS) resources:.

The measurement configuration includes the following parameters:.

A UE in RRC_CONNECTED maintains a measurement object list, a reporting configuration list, and a measurement identities list according to signaling and procedures in this specification. The measurement object list possibly includes NR measurement object(s) and inter-RAT objects. Similarly, the reporting configuration list includes NR and inter-RAT reporting configurations. Any measurement object can be linked to any reporting configuration of the same RAT type. Some reporting configurations may not be linked to a measurement object. Likewise, some measurement objects may not be linked to a reporting configuration.

The measurement procedures distinguish the following types of cells:.

For NR measurement object(s), the UE measures and reports on the serving cell(s), listed cells and/or detected cells. For inter-RAT measurements object(s) of E-UTRA, the UE measures and reports on listed cells and detected cells.

Whenever the procedural specification, other than contained in sub-clause <NUM>. <NUM>, refers to a field it concerns a field included in the VarMeasConfig unless explicitly stated otherwise i.e., only the measurement configuration procedure covers the direct UE action related to the received measConfig.

In some embodiments, the network applies the procedure as follows:.

NOTE: The UE does not consider the message as erroneous if the measIdToRemoveList includes any measId value that is not part of the current UE configuration.

The network applies the procedure as follows:.

For Measurement object removal, the UE shall:.

NOTE: The UE does not consider the message as erroneous if the measObjectToRemoveList includes any measObjectId value that is not part of the current UE configuration.

For Measurement object addition/modification, the UE shall:.

For Reporting configuration removal, the UE shall:.

NOTE: The UE does not consider the message as erroneous if the reportConfigToRemoveList includes any reportConfigId value that is not part of the current UE configuration.

For Reporting configuration addition/modification, the UE shall:.

NOTE: UE does not need to retain the reportConfig with the associated cellForWhichToReportCGI and measId after reporting cgi-Info.

For Quantity configuration, the UE shall:.

For Measurement gap configuration, the UE shall:.

Reference signal measurement timing configuration. The UE shall setup the first SS/PBCH block measurement timing configuration (SMTC) in accordance with the received periodicityAndOffset parameter (providing Periodicity and Offset value for the following condition) in the smtc1 configuration. The first subframe of each SMTC occasion occurs at an SFN and subframe of the NR SpCell meeting the following condition:
<IMG>.

If smtc2 is present, for cells indicated in the pci-List parameter in smtc2 in the same MeasObjectNR, the UE shall setup an additional SS/PBCH block Measurement Timing Configuration (SMTC) in accordance with the received periodicity parameter in the smtc2 configuration and use the Offset (derived from parameter periodicityAndOffset) and duration parameter from the smtc1 configuration. The first subframe of each SMTC occasion occurs at an SFN and subframe of the NR SpCell meeting the above condition:.

On the indicated ssbFrequency, the UE shall not consider SS/PBCH block transmission in subframes outside the SMTC occasion for RRM measurements based on SS/PBCH blocks and for RRM measurements based on CSI-RS.

For Measurement gap sharing configuration, the UE shall:.

Paging allows the network to reach UEs in RRC_IDLE and in RRC_INACTIVE state, and to notify UEs in RRC_IDLE, RRC_INACTIVE and RRC_CONNECTED state of system information change (see subclause <NUM>. <NUM>) and Earthquake and Tsunami Warning System (ETWS)/Commercial Mobile Alert System (CMAS) indications (see subclause <NUM>).

While in RRC_IDLE, the UE monitors the paging channels for CN-initiated paging; in RRC_INACTIVE the UE also monitors paging channels for RAN-initiated paging. A UE need not monitor paging channels continuously though; Paging DRX is defined where the UE in RRC_IDLE or RRC_INACTIVE is only required to monitor paging channels during one Paging Occasions (PO) per DRX cycle (see TS <NUM>). The Paging DRX cycles are configured by the network:.

UE uses the shortest of the DRX cycles applicable i.e., a UE in RRC_IDLE uses the shorter of the first two cycles above, while a UE in RRC_INACTIVE uses the shortest of the three.

The POs of a UE for CN-initiated and RAN-initiated paging are based on the same UE ID, resulting in overlapping POs for both. The number of different POs in a DRX cycle is configurable via system information and a network may distribute UEs to those POs based on their IDs.

When in RRC_CONNECTED, the UE monitors the paging channels in any PO signaled in system information for SI change indication and PWS notification. In case of Bandwidth Adaptation (BA), a UE in RRC_CONNECTED only monitors paging channels on the active Bandwidth Part (BWP) with common search space configured.

Paging optimization for UEs in CM_IDLE: at UE context release, the NG-RAN node may provide the AMF with a list of recommended cells and NG-RAN nodes as assistance info for subsequent paging. The AMF may also provide Paging Attempt Information consisting of a Paging Attempt Count and the Intended Number of Paging Attempts and may include the Next Paging Area Scope. If Paging Attempt Information is included in the Paging message, each paged NG-RAN node receives the same information during a paging attempt. The Paging Attempt Count shall be increased by one at each new paging attempt. The Next Paging Area Scope, when present, indicates whether the AMF plans to modify the paging area currently selected at next paging attempt. If the UE has changed its state to CM CONNECTED the Paging Attempt Count is reset.

Paging optimization for UEs in RRC_INACTIVE: at RAN Paging, the serving NG-RAN node provides RAN Paging area information. The serving NG-RAN node may also provide RAN Paging attempt information. Each paged NG-RAN node receives the same RAN Paging attempt information during a paging attempt with the following content: Paging Attempt Count, the intended number of paging attempts and the Next Paging Area Scope. The Paging Attempt Count shall be increased by one at each new paging attempt. The Next Paging Area Scope, when present, indicates whether the serving NG_RAN node plans to modify the RAN Paging Area currently selected at next paging attempt. If the UE leaves RRC_INACTIVE state the Paging Attempt Count is reset.

The purpose of this procedure is to transmit paging information to a UE in RRC_IDLE or RRC_INACTIVE. This is illustrated in <FIG>.

The network initiates the paging procedure by transmitting the Paging message at the UE's paging occasion as specified in TS <NUM>. The network may address multiple UEs within a Paging message by including one PagingRecord for each UE.

For Reception of the Paging message by the UE, upon receiving the Paging message, the UE shall:.

The Paging message is used for the notification of one or more UEs.

SIB validity, acquisition and request for on demand system information as described in 3GP TS <NUM>.

SIB validity and need to (re)-acquire SIB. The UE shall apply the SI acquisition procedure as defined in clause <NUM>. <NUM> upon cell selection (e.g., upon power on), cell-reselection, return from out of coverage, after reconfiguration with sync completion, after entering the network from another RAT, upon receiving an indication that the system information has changed, upon receiving a Public Warning System (PWS) notification; and whenever the UE does not have a valid version of a stored SIB.

When the UE acquires a Master Information Block (MIB) or a System Information Block (SIB1) or a System Information (SI) message in a serving cell as described in clause <NUM>. <NUM>, and if the UE stores the acquired SIB then the UE shall store the associated areaScope, if present, and the first Public Land Mobile Network (PLMN)-Identity in the PLMN-IdentityInfoList, CellIdentity, systemInformationAreaID, if present, and the valueTag, if present as indicated in the si-SchedulingInfo for the SIB. The UE may use a valid stored version of the SI except MIB and SIB1 e.g., after cell re-selection, upon return from out of coverage or after the reception of SI change indication.

NOTE: The storage and management of the stored SIBs in addition to the SIBs valid for the current serving cell is left to UE implementation.

SI change indication and PWS notification. A modification period is used, i.e., updated SI (other than for ETWS and CMAS) is broadcasted in the modification period following the one where SI change indication is transmitted. The modification period boundaries are defined by SFN values for which SFN mod m = <NUM>, where m is the number of radio frames comprising the modification period. The modification period is configured by system information. The UE receives indications about SI modifications and/or PWS notifications using Short Message transmitted with Paging Radio Network Temporary Identifier (P-RNTI) over Downlink Channel Information (DCI) (see clause <NUM>). Repetitions of SI change indication may occur within preceding modification period.

UEs in RRC_IDLE or in RRC_INACTIVE shall monitor for SI change indication in its own paging occasion every DRX cycle. UEs in RRC_CONNECTED shall monitor for SI change indication in any paging occasion at least once per modification period if the UE is provided with common search space on the active BWP to monitor paging, as specified in TS <NUM>, clause <NUM>.

ETWS or CMAS capable UEs in RRC_IDLE or in RRC_INACTIVE shall monitor for indications about PWS notification in its own paging occasion every DRX cycle. ETWS or CMAS capable UEs in RRC_CONNECTED shall monitor for indication about PWS notification in any paging occasion at least once per modification period if the UE is provided with common search space on the active BWP to monitor paging.

If the UE receives a Short Message, the UE shall:.

Acquisition of MIB and SIB1. The UE shall:.

NOTE: The UE in RRC_CONNECTED is only required to acquire broadcasted SIB1 if the UE can acquire it without disrupting unicast data reception, i.e., the broadcast and unicast beams are quasi co-located.

For SI message acquisition PDCCH monitoring occasion(s) are determined according to searchSpaceOtherSystemInformation. If searchSpaceOtherSystemInformation is set to zero, PDCCH monitoring occasions for SI message reception in SI-window are same as PDCCH monitoring occasions for SIB1 where the mapping between PDCCH monitoring occasions and SSBs is specified in TS <NUM>. If
searchSpaceOtherSystemInformation is not set to zero, PDCCH monitoring occasions for SI message are determined based on search space indicated by
searchSpaceOtherSystemInformation. PDCCH monitoring occasions for SI message which are not overlapping with UL symbols (determined according to Time Division Duplexing (TDD)-Uplink (UL)-Downlink (DL)-ConfigurationCommon) are sequentially numbered from one in the SI window. The [x*N+K]th PDCCH monitoring occasion (s) for SI message in SI-window corresponds to the Kth transmitted SSB, where x = <NUM>, <NUM>,. X-<NUM>, K = <NUM>, <NUM>,. N, N is the number of actual transmitted SSBs determined according to ssb-PositionsInBurst in SIB1 and X is equal to 'CEIL(number of PDCCH monitoring occasions in SI-window/N).

When acquiring an SI message, the UE shall:.

Request for on demand system information. The UE shall:.

NOTE: After Random Access Channel (RACH) failure for SI request it is UE implementation when to retry the SI request.

There currently exist certain challenge(s). With the current NR specification, a UE entering in RRC_CONNECTED mode may not take advantage of the possible CA/DC/MC opportunity. In fact, in current specifications there is no support for early measurements by the UE and thus the network is not able to do a fast setup (or resume) of CA or DC in NR. By early measurement, it is meant that measurement results that can be obtained from the UE without the need to send or restore measurement configurations after the UE has gone to CONNECTED mode. This can preferably be even before the UE has received message <NUM>, e.g., RRCResume, so that the network can configure CA/DC immediately in that command.

Further, even if the measurements performed during the UE in RRC_IDLE or RRC_INACTIVE are sent to the network as soon as the UE gets connected, they may not be accurate enough for the network to decide performing some RRC procedures like e.g., handover or SN change/Modification.

In rel-<NUM> NR, the network may decide to setup CA or DC only after the UE enters in RRC_CONNECTED (e.g., possibly after configuring the UE with a measConfig that contains an A4 event for candidate carriers for SCell addition and receiving a measurement report triggered via this configuration). Of course, this means that the functionalities of CA and DC (i.e., low latencies and high data rate) are not fully exploited in case the UE does not have a huge amount of data in its queue, because by the time a decision to setup CA or DC is made, the data buffer could already be empty and UE might soon be sent back to INACTIVE state. In the worst case, the data may have been buffered too long, beyond the latency requirements of the UE bearer by the time CA/DC is setup. In order to avoid these, it would be beneficial if the UE could provide accurate measurements as early as possible to the network when it goes (or even before it goes) to RRC_CONNECTED. Also, the accuracy of the measurements should be high enough to help the network decides the proper RRC configuration for the UE.

In suspend / resume procedure for NR, the UE in RRC_CONNECTED has a stored measurement configuration (modeled in the specification in the UE variable VarMeasconfig, which is like the IE MeasConfig) and, upon reception of an RRCRelease with suspend configuration, the measurement configuration is stored and connected mode measurements are suspended. Then, when the UE needs to resume (e.g., due to paging, NAS request or RNA update) the UE sends an RRC Resume Request like message and receives an RRCResume message. Only at that point in time the UE enters RRC_CONNECTED, restore the previous configuration and apply the measConfig of MeasConfig IE (possibly as a delta signaling to the stored configuration). That is the point in time during the procedure that network may either activate existing events (e.g., A4) configured to assist the setup of CA/DC or add new events (e.g., A4) configuration. When embodiments disclosed herein add new events or activate existing events here it also includes measurement identifiers and/or measurement objects.

For that reason, with the existing solution in NR, it may take hundreds of milliseconds until the first measurement reports are received at the network after the UE entered RRC_CONNECTED (since measurements are resumed upon the reception of RRC Resume like message and/or the new measurements configured in RRC Resume can only be started after that).

To speed up the availability of measurements during the transitions from idle to connected, in LTE Rel-<NUM> an idle mode measurement solution has been standardized, as described in the background. However, that may not speed up the availability of measurements that much, since it still requires another message exchange via UE information request/response, as shown in the figure below. In addition to latency to acquire the measurements, these idle measurements are not as accurate as connected mode measurements, due to the more relaxed requirements for measurement accuracy when the UE is in IDLE state (and in NR, also in INACTIVE state).

As is shown in <FIG>, in the existing mechanism in LTE Rel-<NUM> the network has to indicate that it supports the request/reception of early idle measurements performed by the UE is an indication in SIB2 (flag indicating the support) so the UE then includes the availability of measurements in RRCConnectionSetupComplete or RRCConnectionResumeComplete. However, that is an indication that the cell / eNodeB supports the feature, but not that the cell/eNodeB wants a specific UE to report the available idle measurements. For that purpose, the LTE Rel-<NUM> solution introduces a flag in the UEInformationRequest message. The UEInformationRequest is sent on SRB1 and sent only after the UE has indicated that it has measurements available.

Another aspect to be highlighted that represents a limitation in the Rel-<NUM> solution for LTE, if applied in NR, is that these early idle measurements are configured by source when the UE enters RRC_IDLE. That takes into account not only the UE capabilities, but also the source node's possibilities to setup carrier aggregation and/or forms of dual connectivity. A validity area is also associated to that which indicates that outside that area, these measurements might not be so interesting any more. Hence, even if these type of solutions as the one for LTE Rel-<NUM> is defined, it is still relevant to enhance the solution for more general cases, where the UE can move and as fast as possible provide measurements to the network, so that CA and/or DC may be setup as fast as possible by the target network node with assistance information via measurements, if needed.

Yet another shortcoming of existing solutions in LTE is that only already available measurement results carried out by the UE are fetched by the Network (NW). As described above in existing solutions, a potential "early measurement" configuration provided to a UE upon connection release (aforementioned measIdleConfig-r15) is accompanied by a validity timer (measIdleDuration-r15) of range <NUM>. <NUM> seconds. It is quite difficult for a NW to tune this timer as it comes with the trade-off; high value leads to wasted UE battery time, whereas short values lead to unavailable measurement results from the UE upon successive connections. Also, the maximum value for this timer is only <NUM> minutes, and quite probable for the UE to have much higher duration between the connection setups. Any other measurements carried out by the UE pass this timer is up to UE implementation and dependent on serving cell quality and priority. As can be found in 3GPP TS <NUM> (LTE) and similarly in <NUM> (Rel-<NUM>) there are various thresholds defined in the specifications (e.g., SIntraSearchP, SIntraSearchQ, SnonIntraSearchP, SnonIntraSearchQ) which control the measurement activity of a UE. A UE that is experiencing good coverage above these thresholds in a cell and on a relatively high priority carrier will not constantly carry out measurements on other carriers. Hence, as also in most cases the UEs are in relatively good coverage, the NW-desired measurement results relevant for the "early measurement" feature are not available in the UE upon connection establishment.

Furthermore, depending on when the UE measured the carriers in RRC Idle state, the measurements might be stale.

Lastly, even if the UE would have measurements available in RRC Idle state, the carriers measured might not necessarily be optimal from UE power saving aspects. , it might be so that the UE happens to have measurement results on carriers not adjacent to each other and the NW based on retrieved results sets up CA on those carriers; whereas other available carriers (suitable from UE power saving perspective) would have been equally fine to set up for CA from NW's perspective.

Last, but not least, it is important to note that idle measurements are performed with lower accuracy requirements compared to connected mode. Hence, even if it is important to get measurements as early as possible, for the sake of the use cases described here, low accuracy measurements may lead to non-optimal decisions, e.g., network adds an SCell that is not with good quality, but that has been reported by the UE as a good cell, according to early idle measurements.

The invention provides solutions to the aforementioned or other challenges. The invention includes a method executed by a wireless terminal/UE for measurement reporting configuration while the UE is in dormant state (e.g., RRC_IDLE/RRC_INACTIVE) the method comprising:.

In the invention, an indicator in the paging message from the NW triggering start of measurements in the UE is combined with other configuration (either broadcast in system information or earlier provided through dedicated messages) i.e., the combination of the two constitutes a measurement configuration. Some further aspects relevant to this aspect are outlined below:.

In all aspects above, additional indicator/configuration can be provided to the UEs informing that the NW is interested in using X number of carriers for CA/DC. The UE would among all carriers provided in the relevant measurement configurations outlined above (for example, having Y carriers configured where potentially Y > X) choose to measure on X out of Y carriers that are beneficial for the UE e.g., in terms of power consumption. For example, the UE may choose to carry out measurement on adjacent carriers utilizing the same HW blocks in the UE.

In the aspects above related to the measurement configuration, the configuration could be not just for one or several carriers but also for one or several cells per each carrier. As an alternative the measurement configuration for a carrier could include a list of cells that are not part of the measurement configuration.

Furthermore, in several of the aspects above, the indicators outlined in the paging message above could either be user-specific or common to all/several UEs receiving the paging message. For example, the indicators could be accompanied with the PagingUE-Identity (<NUM>) transmitted within the PDSCH and only relevant for that specific UE. Alternately, the indictor could be put on a higher level relevant for multiple/all UEs. In one aspect the indicator is put in the PDCCH itself (inside Short message, see <NUM>) rather than PDSCH and would be relevant for all UEs decoding that PDCCH message, or for e.g., all UEs that have received a measurement configuration earlier or for all UEs that support Carrier Aggregation (CA) and/or Dual Connectivity (DC).

Embodiments disclosed herein propose the following solution (from the network perspective):
The network may include an indication to start measurement according to stored configuration in the UE context or provide a measurement configuration within the paging message (or in a broadcast message) and the UE uses such configuration and starts performing measurements even before the reception of the resume message that will officially put the UE in CONNECTED mode.

While the embodiments disclosed herein mainly propose several embodiments to indicate starting measurements during idle/inactive state for enabling fast CA/DC setup, it should also be noted that the network could also use the same embodiments to indicate stopping measurements which are dedicated to fast CA/DC setup.

There are, proposed herein, various embodiments which address one or more of the issues disclosed herein. Systems and methods for triggering measurements before the completion of connection resumption are provided. <FIG> and <FIG> illustrate methods performed by a wireless device for performing measurements, according to some embodiments of the present disclosure. In some embodiments, a method performed by a wireless device for performing measurements where a current Radio Resource Control (RRC) status is: IDLE or INACTIVE. The method includes monitoring for a potential reception of a downlink message in a cell that the wireless device is camping on (step <NUM>); detecting, based upon the reception of the downlink message, information regarding performing measurements (step <NUM>); performing measurements based on the information regarding performing the measurements (step <NUM>); and reporting the measurement results (step <NUM>). In this way, latency might be reduced to start performing measurements. This early availability of measurements at the target cell might increase the speed at which the wireless device acquires wireless connections such as Carrier Aggregation (CA) or Dual Connectivity (DC) connections. In some embodiments, the measurement results are reported based on one or more of an indication/request from the network, when the wireless device resumes, etc..

<FIG> illustrates a method performed by a wireless device for performing measurements. In some embodiments, the method includes monitoring for a potential reception of a message in the downlink in a cell that the wireless device is camping on (step <NUM>); monitoring network broadcast message (step <NUM>); detecting, based upon the reception of the downlink message or the broadcast message, information regarding performing measurements (step <NUM>); performing measurements based on the information regarding performing measurements (step <NUM>); and reporting the measurement results (step <NUM>).

In some embodiments, the potential reception of a message is a potential reception of a paging message or any other message multiplexed with the paging message. In some embodiments, the network broadcast message is a SIB4. In some embodiments, the information regarding performing measurements comprises an indication to resume measurements according to a stored configuration in the wireless device. In some embodiments, the stored configuration is stored in a UE AS Context.

In some embodiments, the information regarding performing measurements comprises a measurement configuration that indicates that the wireless device shall perform new measurements according to the configuration received. In some embodiments, the measurement configuration provided may comprise lists of measurement objects, report configuration, measurement identifiers, associations between these, etc..

If the received indication was to restore the measurement configuration, the method also includes restoring the stored measurement configuration. If a measurement configuration was included, the method includes restoring the stored measurement configuration and applying the received measurement configuration on top of it. In some embodiments, applying the received measurement configuration on top of it comprises either as a delta or full configuration. In some embodiments, the decision of a delta or full configuration is based on a need code structure in MeasConfig IE.

In some embodiments, reporting the measurement results comprises waiting until after security is activated.

Systems and methods for triggering measurements before the completion of connection resumption are provided. <FIG> and <FIG> illustrate methods performed by a base station for enabling measurements, according to some embodiments of the present disclosure. In some embodiments, a method performed by a base station for enabling measurements for a wireless device where a current RRC status of the wireless device is: IDLE or INACTIVE. The method includes determining whether or not to enable measurements for the wireless device (step <NUM>); sending an indication to start measurements to the wireless device camping on a cell of the base station (<NUM>); and receiving measurement results from the wireless device performed before the reception of a resume message (step <NUM>). In this way, latency might be reduced to start performing measurements. This early availability of measurements at the target cell might increase the speed at which the wireless device acquires wireless connections such as CA or DC connections.

<FIG> illustrates a method performed by a base station for enabling measurements. In some embodiments, the method includes sending an indication to start measurements to a wireless device camping on a cell of the base station (step <NUM>); and receiving measurement results from the wireless device performed before the reception of a resume message (step <NUM>).

Certain embodiments may provide one or more of the following technical advantage(s). Embodiments disclosed herein enable the UE to start performing connected mode measurements upon the reception of a paging like message in a target cell. Compared to the state of the art solution, where that would only be possible upon the reception of the RRC Resume like message, a gain in latency of at least <NUM> radio Round Trip Times (RTTs) (i.e., RACH preamble, RAR, Resume Request, Resume) to start performing measurements is achieved, which may be quite valuable for early availability of measurements at the target cell, according to a configuration possibly decided by target, which may be according to the target's capabilities e.g., its supported carriers and/or exact SCells. The <NUM> radio RTT is actually the lower end of expected performance enhancement, because the RAR may not succeed in just one attempt and UE has to do some power ramping before that succeeds, and also tens of milliseconds may elapse, depending on network load and radio conditions, between the sending of the resume request and the reception of the resume message. So in reality, the methods proposed by embodiments disclosed herein may end up making the measurement results available to the network <NUM> of milliseconds earlier as compared to the legacy way of starting the measurement after receiving the resume message.

In several aspects of the embodiments disclosed herein, the design of the measurement configuration parameters provided from the NW to the UE requires much less effort from the NW operators. This is due to that the configuration is provided locally from the node that is interested in receiving the measurement results rather than from a distant node (e.g., where the UE got suspended). Furthermore, no validity timer/area is limiting the proposed solution for setting up CA/DC as it is based on configuration relevant in the area received and measurements triggered by the UE just before setting up a connection. Lastly in some aspects outlined in the embodiments disclosed herein, the UE has a chance to choose specific carriers beneficial in terms of UE power saving among NW provided carriers.

In the some embodiments, the network indicates in the paging message the UE to resume performing measurements according to the configuration the UE has stored upon being suspended.

In a second embodiment, the network includes a measurement configuration into the paging message. In another embodiment, more than one configuration can be included in the paging message where each measurements configuration may include different parameters, carriers and/or cells to measure, and, in general, different level of accuracy for the measurements. Yet, in another embodiment, if the UE has been previously configured with more than one measurement configuration before going to RRC_IDLE or RRC_INACTIVE, the network can add in the paging message an indication to the UE on what configuration need to be used/activated.

In one embodiment, a complete measurement configuration is included within the paging message (e.g., the entire measConfig). In another embodiment, due to the limitation on the paging message size, only a subset of selected fields within measConfig is included. Yet, in another embodiment, no measConfig is included in the paging message but only the selected fields that need to be signaled. In yet another embodiment, the measurement configuration is included in a separate message. Such a separate message may either be addressed to several different UEs or only be addressed to a single UE. In the latter case, the message can then be sent to the UE using a security key to support security at the configuration. In one alternative the scheduling of the separate message with the measurement configuration is scheduled within the paging message. In another alternative it is transmitted at a predefined occasion, e.g., related to where the paging message is transmitted. In yet another alternative the UE uses a specific identity to search for a scheduling (for the message) on the PDCCH, where the identity may be included e.g., in the paging message.

In one embodiment, these measurement-related parameters are included (by delta signaling) to the current measurement configuration used by the UE. In another embodiment, these measurement-related parameters are considered as a new measurement configuration (basically the UE builds a new measConfig with this subset of parameters received). This can be indicated either explicitly one by one (e.g., all the old measurements are removed explicitly via the inclusion of IEs such as measIdToRemoveList, measObjectToRemoveList, etc. and new ones added via measIdToAddModList, measObjectToAddRemoveList, etc.) or implicitly via a new flag (e.g., fullconfigmeas) that is added in the measurementConfiguration.

In further embodiments, the network could use the same embodiments that are described above to stop/suspend measurements which are dedicated to fast CA/DC setup. This could be due to a policy change regarding a specific UE or a network or due to a temporary load condition in the network. In case of stopping the measurements, the measurement configuration could be completely removed from the UE and network memories. In case of suspending measurements, the measurement configuration can be stored by the UE and the network but not applied by the UE.

The following is an example of implementation for the case where the network includes the indication for the UE to resume measurements according to stored configuration in the UE context. The specification into which the following should be implemented is 3GPP TS <NUM>.

The purpose of this procedure is to transmit paging information to a UE in RRC_IDLE or RRC_INACTIVE.

Upon receiving the Paging message, the UE shall:.

In another realization, just one startMeas indication is included in the paging message and is applicable to all the UEs being paged.

The paging procedure then will look like the one shown below:
Reception of the Paging message by the UE.

The following is an example of implementation for the case where the network includes the measurement configuration within the paging message. The specification into which the following should be implemented is 3GPP TS <NUM>.

Measurement configuration that may be transmitted in a message transmitted in a paging like channel.

In the embodiments disclosed herein, what is called a paging like channel may be the paging channel. And, the measurement configuration may be a field called measConfig with MeasConfigIE, as shown below:.

The IE MeasConfig specifies measurements to be performed by the UE, and covers intra-frequency, inter-frequency and inter-RAT mobility as well as configuration of measurement gaps.

Notice that the need codes apply as if the empty field is included i.e., if UE has stored measurement configurations, these shall be restored and measurements accordingly shall be resumed.

Note that it may not be necessary to use the full measConfig for the measurements to be configured via paging. For example, what the network needs could be just information about some carriers. So the measConfig could be just a list of carrier frequencies to measure and the UE reports the signal level of the top n cells on each frequency. If such an approach is to be taken, an early measurement configuration (e.g., earlyMeasConfig) IE needs to be specified that includes the required IE (in the example case, containing just a list of frequencies) and the UE measurement procedure needs to be updated to handle such measurement configurations. An advantage of having such a simplified approach is that the measurement configuration can be included only once in the paging message and could be applicable to all the UEs.

<FIG> is a schematic block diagram of a radio access node <NUM> according to some embodiments of the present disclosure. The radio access node <NUM> may be, for example, a base station <NUM> or <NUM>. As illustrated, the radio access node <NUM> includes a control system <NUM> that includes one or more processors <NUM> (e.g., Central Processing Units (CPUs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), and/or the like), memory <NUM>, and a network interface <NUM>. The one or more processors <NUM> are also referred to herein as processing circuitry. In addition, the radio access node <NUM> includes one or more radio units <NUM> that each includes one or more transmitters <NUM> and one or more receivers <NUM> coupled to one or more antennas <NUM>. The radio units <NUM> may be referred to or be part of radio interface circuitry. In some embodiments, the radio unit(s) <NUM> is external to the control system <NUM> and connected to the control system <NUM> via, e.g., a wired connection (e.g., an optical cable). However, in some other embodiments, the radio unit(s) <NUM> and potentially the antenna(s) <NUM> are integrated together with the control system <NUM>. The one or more processors <NUM> operate to provide one or more functions of a radio access node <NUM> as described herein. In some embodiments, the function(s) are implemented in software that is stored, e.g., in the memory <NUM> and executed by the one or more processors <NUM>.

As used herein, a "virtualized" radio access node is an implementation of the radio access node <NUM> in which at least a portion of the functionality of the radio access node <NUM> is implemented as a virtual component(s) (e.g., via a virtual machine(s) executing on a physical processing node(s) in a network(s)). As illustrated, in this example, the radio access node <NUM> includes the control system <NUM> that includes the one or more processors <NUM> (e.g., CPUs, ASICs, FPGAs, and/or the like), the memory <NUM>, and the network interface <NUM> and the one or more radio units <NUM> that each includes the one or more transmitters <NUM> and the one or more receivers <NUM> coupled to the one or more antennas <NUM>, as described above. The control system <NUM> is connected to the radio unit(s) <NUM> via, for example, an optical cable or the like. The control system <NUM> is connected to one or more processing nodes <NUM> coupled to or included as part of a network(s) <NUM> via the network interface <NUM>. Each processing node <NUM> includes one or more processors <NUM> (e.g., CPUs, ASICs, FPGAs, and/or the like), memory <NUM>, and a network interface <NUM>.

In this example, functions <NUM> of the radio access node <NUM> described herein are implemented at the one or more processing nodes <NUM> or distributed across the control system <NUM> and the one or more processing nodes <NUM> in any desired manner. In some particular embodiments, some or all of the functions <NUM> of the radio access node <NUM> described herein are implemented as virtual components executed by one or more virtual machines implemented in a virtual environment(s) hosted by the processing node(s) <NUM>. As will be appreciated by one of ordinary skill in the art, additional signaling or communication between the processing node(s) <NUM> and the control system <NUM> is used in order to carry out at least some of the desired functions <NUM>. Notably, in some embodiments, the control system <NUM> may not be included, in which case the radio unit(s) <NUM> communicate directly with the processing node(s) <NUM> via an appropriate network interface(s).

<FIG> is a schematic block diagram of a UE <NUM> according to some embodiments of the present disclosure. As illustrated, the UE <NUM> includes one or more processors <NUM> (e.g., CPUs, ASICs, FPGAs, and/or the like), memory <NUM>, and one or more transceivers <NUM> each including one or more transmitters <NUM> and one or more receivers <NUM> coupled to one or more antennas <NUM>. The transceiver(s) <NUM> includes radio-front end circuitry connected to the antenna(s) <NUM> that is configured to condition signals communicated between the antenna(s) <NUM> and the processor(s) <NUM>, as will be appreciated by on of ordinary skill in the art. The processors <NUM> are also referred to herein as processing circuitry. The transceivers <NUM> are also referred to herein as radio circuitry. In some embodiments, the functionality of the UE <NUM> described above may be fully or partially implemented in software that is, e.g., stored in the memory <NUM> and executed by the processor(s) <NUM>. Note that the UE <NUM> may include additional components not illustrated in <FIG> such as, e.g., one or more user interface components (e.g., an input/output interface including a display, buttons, a touch screen, a microphone, a speaker(s), and/or the like and/or any other components for allowing input of information into the UE <NUM> and/or allowing output of information from the UE <NUM>), a power supply (e.g., a battery and associated power circuitry), etc..

With reference to <FIG>, in accordance with an embodiment, a communication system includes a telecommunication network <NUM>, such as a 3GPP-type cellular network, which comprises an access network <NUM>, such as a RAN, and a core network <NUM>. The access network <NUM> comprises a plurality of base stations 1706A, 1706B, 1706C, such as NBs, eNBs, gNBs, or other types of wireless Access Points (APs), each defining a corresponding coverage area 1708A, 1708B, 1708C. Each base station 1706A, 1706B, 1706C is connectable to the core network <NUM> over a wired or wireless connection <NUM>. A first UE <NUM> located in coverage area 1708C is configured to wirelessly connect to, or be paged by, the corresponding base station 1706C. A second UE <NUM> in coverage area 1708A is wirelessly connectable to the corresponding base station 1706A.

It is noted that the host computer <NUM>, the base station <NUM>, and the UE <NUM> illustrated in <FIG> may be similar or identical to the host computer <NUM>, one of the base stations 1706A, 1706B, 1706C, and one of the UEs <NUM>, <NUM> of <FIG>, respectively.

The wireless connection <NUM> between the UE <NUM> and the 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 the UE <NUM> using the OTT connection <NUM>, in which the wireless connection <NUM> forms the last segment. More precisely, the teachings of these embodiments may improve the e.g., data rate, latency, power consumption, etc. and thereby provide benefits such as e.g., reduced user waiting time, relaxed restriction on file size, better responsiveness, extended battery lifetime, etc..

The measurements may be implemented in that the software <NUM> and <NUM> causes messages to be transmitted, in particular empty or'dummy' messages, using the OTT connection <NUM> while it monitors propagation times, errors, etc..

Claim 1:
A method performed by a wireless device for performing measurements where a current Radio Resource Control, RRC, status is one of the group consisting of: IDLE; and INACTIVE, the method comprising:
monitoring (<NUM>) for a potential reception of a downlink message from a base station in a cell that the wireless device is camping on, wherein the potential reception of the downlink message is a potential reception of one of the group consisting of: a paging message; and a message multiplexed with the paging message;
detecting (<NUM>), based upon the reception of the downlink message, information regarding performing measurements, wherein the information regarding performing measurements comprises a measurement configuration that indicates that the wireless device shall perform new measurements according to the configuration received, restore a stored measurement configuration and apply the received measurement configuration on top of the stored measurement configuration;
performing (<NUM>) measurements, based on the information regarding performing the measurements, before reception of a resume message putting the wireless device in CONNECTED mode; and
reporting (<NUM>) measurement results to the base station.