CN116349273B

CN116349273B - Apparatus, method and computer program

Info

Publication number: CN116349273B
Application number: CN202080106612.2A
Authority: CN
Inventors: 杜蕾; L·达尔斯加德
Original assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Current assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Priority date: 2020-10-23
Filing date: 2020-10-23
Publication date: 2024-07-05
Anticipated expiration: 2040-10-23
Also published as: WO2022082779A1; CN116349273A

Abstract

There is provided an apparatus configured to: determining a first scale factor for determining a first measurement delay for measuring a first type of reference signal; determining a second scale factor for determining a second measurement delay for measuring a second type of reference signal; determining the first measured delay and the second measured delay; and using the first measurement delay and the second measurement delay for a period of time in which measurements of the first type of reference signal and the second type of reference signal are performed.

Description

Apparatus, method and computer program

Technical Field

The present application relates to apparatus, methods and computer programs and relates particularly, but not exclusively, to apparatus, methods and computer programs for network devices.

Background

A communication system may be considered a facility for effectuating a communication session between two or more entities, such as user terminals, access nodes, and/or other nodes, by providing carriers between the various entities involved in the communication path. The communication system may be provided, for example, by means of a communication network and one or more compatible communication devices. The communication session may include, for example, data communications for carrying communications such as voice, electronic mail (email), text messages, multimedia, and/or content data. The content may be multicast (multicast) or unicast to the communication devices.

The user may access the communication system through an appropriate communication device or terminal. The communication equipment of a user is often referred to as User Equipment (UE) or user equipment. The communication device may access a carrier provided by the access node and transmit and/or receive communications on the carrier.

Communication systems and associated devices typically operate in accordance with a desired standard or specification which sets out what the various entities associated with the system are permitted to do and how that should be achieved. Communication protocols and/or parameters which should be used for the connection are also typically defined. One example of a communication system is UTRAN (3G radio). Another example of a known architecture is the Long Term Evolution (LTE) or Universal Mobile Telecommunications System (UMTS) radio access technology. Another example communication system is the so-called 5G radio or new air interface (NR) access technology.

Disclosure of Invention

According to a first aspect, there is provided an apparatus comprising: means for determining a first scale factor for determining a first measurement delay for measuring a first type of reference signal; means for determining a second scaling factor for determining a second measurement delay for measuring a second type of reference signal; means for determining the first measured delay and the second measured delay; and means for using the first measurement delay and the second measurement delay for a period of time in which measurements of the first type of reference signal and the second type of reference signal are performed.

The first type of reference signal may be a channel state information reference signal and the second type of reference signal may be a synchronization signal block.

The first scaling factor and the second scaling factor may be carrier specific scaling factors.

The means for determining the first scale factor and the second scale factor may comprise: means for determining a degree of overlap between the first type of reference signal and the second type of reference signal; and means for determining the first scale factor and the second scale factor based on the degree of overlap.

The first and second scale factors may be determined independently of each other when the determined degree of overlap indicates that the first and second type reference signals do not overlap in time.

The first and second scale factors may be determined interdependently when the determined degree of overlap indicates that the first and second type reference signals at least partially overlap in time.

When the determined degree of overlap indicates that the first type of reference signal and the second type of reference signal partially or completely overlap in time, the value of the first scale factor may be twice the value of the first scale factor when the first type of reference signal and the second type of reference signal do not overlap in time, and the value of the second scale factor may be twice the value of the second scale factor when the first type of reference signal and the second type of reference signal do not overlap in time.

When the determined degree of overlap indicates that the first type of reference signal and the second type of reference signal partially overlap in time, the first scale factor may include a primary additional scale factor and the second scale factor includes a secondary additional scale factor.

When the determined degree of overlap is generated by periods of the opposing first and second reference signals, the first scale factor may include a primary additional scale factor and the second scale factor includes a secondary additional scale factor.

The apparatus may include means for determining the primary additional scale factor and the secondary additional scale factor, the means comprising: means for determining the primary additional scale factor; and means for determining the auxiliary additional scale factor; wherein the primary and secondary additional scale factors are determined from an availability period of the first type of reference signal and an availability period of the second type of reference signal.

The additional scale factor may be determined by calculating an overlap factor F, wherein:

F=max (INT (second type transmission period/first type transmission period), INT (first type transmission period/second type transmission period)),

Where INT is the exact division value or integer part of the division value.

The first scaling factor may be determined to be higher when the availability of the first type of reference signal is at least partially overlapping in time with the availability of the second type of reference signal than when the availability of the first type of reference signal is not overlapping in time with the availability of the second type of reference signal.

The first scale factor may be 1 and the second scale factor may not be equal to 1.

The first scale factor may not be equal to 1 and the second scale factor may be equal to 1.

According to a second aspect, there is provided an apparatus comprising: at least one processor; and at least one memory including code that, when executed by the at least one processor, causes the processor to: determining a first scale factor for determining a first measurement delay for measuring a first type of reference signal; determining a second scale factor for determining a second measurement delay for measuring a second type of reference signal; determining the first measured delay and the second measured delay; and using the first measurement delay and the second measurement delay for a period of time in which measurements of the first type of reference signal and the second type of reference signal are performed.

Determining the first scale factor and the second scale factor may include: determining a degree of overlap between the first type of reference signal and the second type of reference signal; the first scale factor and the second scale factor are determined according to the degree of overlap.

The apparatus may determine the primary additional scale factor and the secondary additional scale factor by: determining the primary additional scale factor; and determining the auxiliary additional scale factor; wherein the primary and secondary additional scale factors are determined from an availability period of the first type of reference signal and an availability period of the second type of reference signal.

Where INT is the exact division value or integer part of the division value.

The first scale factor may be determined to be higher when the availability of the first type of reference signal is at least partially overlapping in time with the availability of the second type of reference signal than when the availability of the first type of reference signal is not overlapping in time with the availability of the second type of reference signal.

According to a third aspect, there is provided a method for an apparatus, the method comprising: determining a first scale factor for determining a first measurement delay for measuring a first type of reference signal; determining a second scale factor for determining a second measurement delay for measuring a second type of reference signal; determining the first measured delay and the second measured delay; and using the first measurement delay and the second measurement delay for a period of time in which measurements of the first type of reference signal and the second type of reference signal are performed.

The method may include determining the primary additional scale factor and the secondary additional scale factor by: determining the primary additional scale factor; determining the auxiliary additional scale factor; wherein the primary and secondary additional scale factors are determined from an availability period of the first type of reference signal and an availability period of the second type of reference signal.

Where INT is the exact division value or integer part of the division value.

According to a fourth aspect, there is provided an apparatus comprising: a determination circuit for determining a first scale factor of a first measurement delay for measuring a first type of reference signal; a determination circuit for determining a second scale factor for a second measurement delay, the second measurement delay for measuring a second type of reference signal; a determination circuit for determining the first measured delay and the second measured delay; and a usage circuit that uses the first measurement delay and the second measurement delay for a period of time in which measurements of the first type of reference signal and the second type of reference signal are performed.

The determining circuit for determining the first scale factor and the second scale factor may include: a determination circuit for determining a degree of overlap between the first type of reference signal and the second type of reference signal; and a determining circuit for determining the first scale factor and the second scale factor according to the degree of overlap.

The apparatus may include a determination circuit for determining the primary additional scale factor and the secondary additional scale factor, the determination circuit comprising: a determination circuit for determining the primary additional scale factor; and a determination circuit for determining the auxiliary additional scale factor; wherein the primary and secondary additional scale factors are determined from an availability period of the first type of reference signal and an availability period of the second type of reference signal.

Where INT is the exact division value or integer part of the division value.

According to a fifth aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to at least: determining a first scale factor for determining a first measurement delay for measuring a first type of reference signal; determining a second scale factor for determining a second measurement delay for measuring a second type of reference signal; determining the first measured delay and the second measured delay; and using the first measurement delay and the second measurement delay for a period of time in which measurements of the first type of reference signal and the second type of reference signal are performed.

The apparatus may be caused to determine the primary additional scale factor and the secondary additional scale factor by: determining the primary additional scale factor; determining the auxiliary additional scale factor; wherein the primary and secondary additional scale factors are determined from an availability period of the first type of reference signal and an availability period of the second type of reference signal.

Where INT is the exact division value or integer part of the division value.

According to a sixth aspect, there is provided a computer program comprising program instructions for causing a computer to perform any of the methods as described above.

According to a seventh aspect, there is provided a computer program product stored on a medium, which can cause an apparatus to perform any of the methods as described herein.

According to an eighth aspect, there is provided an electronic device, which may comprise an apparatus as described herein.

According to a ninth aspect, there is provided a chipset, which may comprise an apparatus as described herein.

Various other aspects are also described in the following detailed description and the appended claims.

Drawings

Embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 shows a schematic diagram of a 5G system;

FIG. 2 shows a schematic diagram of a network device;

Fig. 3 shows a schematic diagram of a user equipment;

FIG. 4 shows a schematic diagram of a non-volatile storage medium storing instructions that, when executed by a processor, allow the processor to perform one or more steps of a method of some embodiments;

Fig. 5A to 7 show example transmissions relative to a measurement window; and

Fig. 8 is a flow chart illustrating potential operation of an example apparatus.

Detailed Description

In the following, certain embodiments are explained with reference to mobile communication devices capable of communicating via a wireless cellular system and mobile communication systems serving such mobile communication devices. Before explaining the exemplary embodiments in detail, some general principles of a 5G wireless communication system are briefly explained with reference to fig. 1.

Fig. 1 shows a schematic diagram of a 5G system (5 GS) 100. The 5GS may include a User Equipment (UE) 102 (which may also be referred to as a communication device or terminal), a 5G Access Network (AN) (which may be a 5G Radio Access Network (RAN) or any other type of 5G AN, such as a non-3 GPP interworking function (N3 IWF)/trusted non-3 GPP gateway function (TNGF) for untrusted/trusted non-3 GPP access or a wired access gateway function (W-AGF) for wired access) 104,5G core (5 GC) 106, one or more Application Functions (AFs) 108, and one or more Data Networks (DNs) 110.

The 5G RAN may include one or more gndeb (gNB) distributed element functions coupled to one or more gndeb (gNB) element functions. The RAN may include one or more access nodes.

The 5gc 106 can include one or more Access Management Functions (AMFs) 112, one or more Session Management Functions (SMFs) 114, one or more authentication server functions (AUSF) 116, one or more Unified Data Management (UDM) functions 118, one or more User Plane Functions (UPFs) 120, one or more unified data store (UDR) functions 122, one or more network store functions (NRFs) 128, and/or one or more network open functions (NEFs) 124. Although NRF 128 is not depicted as having its interfaces, it should be understood that this is for clarity and NRF 128 may have multiple interfaces with other network functions.

The 5gc 106 also includes a network data analysis function (NWDAF) 126.NWDAF are responsible for providing network analysis information upon request from one or more network functions or devices within the network. The network functions may also subscribe NWDAF to receive information from. Accordingly, NWDAF 126,126 is also configured to receive and store network information from one or more network functions or devices within the network. The data collection of NWDAF 126,126 may be performed based on at least one subscription to events provided by at least one network function.

The 5GC (5G core network) has been defined as a Service Based Architecture (SBA). The service-based architecture provides a modular framework from which generic applications can be deployed using components of different sources and vendors. Thus, the control plane functions and common data store of a 5G network may be delivered through a set of interconnected Network Functions (NF), each having services authorized to access each other, the Network Function (NF) service producer opening the services to NF service consumers. NF can act as a service consumer and/or service provider. NF service providers register their NF profiles in a Network Repository Function (NRF). The NRF maintains an update repository of 5G elements available in the operator network, as well as services provided by each element in the 5G core, which are expected to be instantiated, extended, and/or terminated with no or minimal human intervention. In other words, the NRF maintains a record of available NF instances and their supporting services. NRF allows other NF instances to subscribe to and notify registrations from NF instances of a given type. NRF can support service discovery by receiving a discovery request from NF instance and detailed information that NF instance supports a specific service. Thus, NF service consumers or service communication agents (SCPs), which obtain NF services on behalf of another network entity, may discover NF service producers by performing NF discovery procedures, e.g., on NRFs.

In 5G NR, the signal strength or signal quality matrix of the serving cell and the neighboring cells may be determined for various purposes/procedures, including over-handoff (handover) or adding a new Carrier Component (CC) in the case of carrier aggregation. This helps to maintain the radio link quality for maintaining the service level.

In 5G NR, the concept of cell signal measurement is performed by using a synchronization signal/physical broadcast channel block (SSB), which may include a Synchronization Signal (SS) having a longer transmission period than CRS, and a Physical Broadcast Channel (PBCH).

The 3GPP specifications introduce an SSB-based Radio Resource Management (RRM) measurement timing configuration window (also referred to as a Synchronized Measurement Timing Configuration (SMTC) window) that may be used to inform the UE about the measurement periods and timings that the UE may use to measure SSBs. A measurement gap is also introduced. The measurement gap may be used to measure inter-frequency cells. The location of the gap is configurable and is not necessarily between SMTCs. The UE may be configured with information about SMTC windows and measurement gaps (e.g., size and period) through measurement configuration. The measurement configuration may be provided by Radio Resource Control (RRC) signaling.

Recent discussions in the 3GPP work group have focused on how to make measurements in 5G networks. In particular, it has been explored how layer 3/network layer measurements can be made from Channel State Information (CSI) Reference Signals (RSs). Among other functions, CSI-RS is a downlink-only signal for downlink acquisition. CSI-RS is designed for tracking and beam management and mobility management.

Layer three measurements based on CSI-RS can provide finer beam information than measurements based on Synchronization Signal Blocks (SSBs), which means that the network can steer the UE to a better beam during handoff or during other procedures. Measurement functions based on CSI-RS have been defined.

In discussing CSI-RS based layer 3 measurements, many aspects currently need to be considered. For example, a single Fast Fourier Transform (FFT) assumes multiple cell measurements for each frequency layer of both on-channel and off-channel measurements, minimum requirements associated with the measurement bandwidth of CSI-RS, on-channel and off-channel definition and measurement requirements based on CSI-RS, the need to evaluate and specify layer three measurement accuracy based on CSI-RS, and the capability for CSI-RS based measurements (including frequency layer number and cell number, etc.) to introduce new UE measurement capability.

Current CSI-RS measurement requirements are specified in 3gpp TS 38.133 section 9. This section defines a Carrier Specific Scaling Factor (CSSF) for scaling measurement delay requirements when a UE is configured to monitor multiple measurement objects. For measurements made on measurement object i, the CSSF values are classified as CSSF _{outside_gap,i} and CSSF _{within_gap,i} for measurements made outside and inside the measurement gap, respectively. With this scaling factor, the measurement requirements (including at least the primary synchronization signal/secondary synchronization signal detection time, the time period for acquisition of the SSB index, and the measurement period defined in the specification) are multiplied by this factor. This results in the UE being allowed more measurement time or delay when configured with multiple measurement objects, as the UE is expected to measure multiple measurement objects. UEs that have allowed more measurement time are described as having more "relaxed" requirements.

CSSF _{outside_gap,i} can be applied to a variety of different measurement types.

When none of SMTC measurement occasions of the on-channel measurement object overlap with the measurement gap, the first measurement type is on-channel measurement without the measurement gap.

When a portion of SMTC measurement occasions of the on-channel measurement object overlap with the measurement gap, the second measurement type is on-channel measurement without the measurement gap.

When the SSB-based measurement timing configuration timing of the inter-frequency measurement object does not overlap with the measurement gap, the third measurement type is inter-frequency measurement without the measurement gap.

When a part of the SSB-based measurement timing configuration timing of the inter-frequency measurement object overlaps with the measurement gap, the fourth measurement type is an inter-frequency measurement without the measurement gap.

Table 1 shows CSSF _{outside_gap,i} scale factors for the SA mode defined in the specification.

TABLE 1 Scale factors for the CSSF _{outside_gap,i} independent mode

In this table, for FR1 and FR2 inter-band carrier aggregation, only one Frequency Range (FR) operating band FR1 and one frequency range operating band FR2 are included. Furthermore, CSSF _{outside_gap,i} =1 only when one SCell is configured, y is the number of configured inter-frequency measurement objects without measurement gaps measured outside the measurement gap, and only two NR FR2 operating bands are included for FR2 inter-band CA.

In the Rel16 CSI-RS based measurement discussion, if the center frequency of the CSI-RS resource in the target cell is the same as the center frequency of the serving cell, the CSI-RS based measurement is considered to be the same frequency measurement and the subcarrier spacing is the same. Furthermore, co-frequency measurement requirements may be applied when the bandwidth of CSI-RS resources on co-frequency neighbor cells is completely within the active bandwidth portion. Thus, for co-channel measurements, CSI-RS resources may be measured without gaps. CSSF _{outside_gap,i} may be applied to intra-frequency CSI-RS based measurements when not all CSI-RS measurement occasions of the measurement object overlap with the measurement gap.

Furthermore, CSSF outside the measurement gap may be specified based on the following assumption: CSI-RS and SSB-based measurement sharing were previously assumed for two measurement engines (also referred to as "searchers" in the SSB discussion) based on SSB measurements. That is, the UE may not be able to monitor or measure the SSB and the CSI-RS simultaneously.

The CSSF table was initially agreed upon in the previous RAN4 conference. Table 2 (below) shows one example of CSSF _{outside_gap,i}, considering the case of configuring CSI-RS based measurements.

TABLE 2 CSSF _{outside_gap,i} Scale factors when configuring CSI-RS based measurements

The table considers the Frequency Ranges (FR) FR1 and FR2, and for simplicity, the FR1+ FR2 inter-band carrier aggregation includes only one FR1 operating band and one FR2 operating band. In addition, Y is the number of measurement objects of different frequencies of the arrangement without measurement gaps measured outside the measurement gaps.

The above protocol means that the UE needs to detect the configured associated SSB before the UE is allowed to measure the associated CSI-RS resources. The associated SSB may be considered to be the SSB associated with the CSI-RS resource to be measured. That is, the current assumption is that the UE is expected to measure both the SSB layer and the CSI-RS layer (i.e., both the center frequencies of the CSI-RS resources) of the associated SSB. According to table 2, for the on-channel CSI-RS based measurement performed outside the gap, CSSF (i.e., CSSF _{outside_gap,i}) of the FR1 primary component carrier is set to 2. This means that when performing CSI-RS, UE double relaxation is allowed (i.e. the amount of measurement time doubles), so it is assumed that both the associated SSB and CSI-RS are always measured. Since the two reference signals cannot be measured at the same time, the measurement time or delay increases. In this example, the measurement delay requirement of the measurement object will be prolonged by 2, since two layers need to be measured at different times. Similarly, for FR1 secondary component carriers, 2 is set for each co-channel layer to be measured. This extension is strongly based on the worst case assumption that SSB and CSI-RS overlap completely in the time domain, which results in reasoning about why UE needs relaxation, since (in the worst case) UE will use the same searcher engine to process both SSB and CSI-RS. These measurements are alternately performed in the time domain.

However, it is also agreed not to associate CSI-RS positions with SMTC windows.

Thus, CSI-RS resources for layer three measurements may be configured within a 5ms window at any location that may overlap completely, incompletely or partially, or not overlap at all with SMTC.

Fig. 5A to 5C illustrate three cases in which CSI-RS resource locations are different with respect to SSB-based measurement timing configuration (SMTC). In particular, fig. 5A-5C illustrate the timing (along the x-axis) of the on-channel CSI reference signal and SSB availability or measurement relative to the SSB-based measurement timing configuration. For on-channel CSI-RS based measurements, the UE will only make measurements within the active bandwidth portion.

Hereinafter, reference is made to signal availability/availability of signals, these phrases being used interchangeably. If a signal is configured to be provided within the time frame, the signal may be deemed available within the time frame. For example, a signal may be considered available if it is available for transmission and/or reception within the time frame. It should be understood that this applies throughout this specification.

Fig. 5A shows CSI-RS transmissions from a serving cell 501, a first neighboring cell 502, and a second neighboring cell 503, all available after an allocated SMTC window 505. SSB transmission 504 may occur within allocated SMTC time 505. This example may be referred to as a completely non-overlapping case.

In this example of fig. 5A, the UE may measure CSI-RS outside of the SSB-based measurement timing configuration configured for SSB measurements. This does not affect the measurement of CSI-RS resources and therefore does not require extension of the measurement delay requirement of the measurement object. In other words, in this example, CSSF may be set to 1 for one service carrier.

Fig. 5B shows CSI-RS transmissions from a serving cell 501', a first neighboring cell 502', and a second neighboring cell 503', all available within an allocated SMTC time 505'. If a signal is configured to be provided within the time frame, the signal may be deemed available within the time frame. For example, a signal may be considered available if it is available for transmission and/or reception within the time frame. SSB transmission 504 'may occur within allocated SMTC time 505'. This example may be referred to as a full overlap case.

For this example of fig. 5B, all of the CSI-RS resources to be measured are configured within and overlap with SMTCs in which the UE expects to measure SSBs.

Fig. 5C shows CSI-RS transmissions from a serving cell 501", a first neighboring cell 502", and a second neighboring cell 503 ". Transmissions from serving cell 501 "and first neighbor cell 502" are available within allocated SMTC time 505", while transmissions from the second neighbor cell are available after allocated SMTC time 505". SSB transmission 504 "may occur within allocated SMTC time 505". This example may be referred to as a partially overlapping case.

For this example of fig. 5C, some of the CSI-RS resources are configured within and overlap with SSB-based measurement timing configurations, while other CSI-RS resources do not overlap with SSB-based measurement timing configurations. Some UEs may not be able to process CSI-RS and SSB measurements simultaneously due to hardware sharing (e.g., shared searcher), which is an assumption in Rel16 to develop minimum UE requirements. This means that the measurement delay requirement needs to be conditionally extended to ensure that a certain number of samples can be derived for both CSI-RS and SSB based measurements. Thus, the CSSF (i.e., CSSF _{outside_gap,I}) for on-channel CSI-RS measurement may be defined to consider whether the CSI-RS position completely overlaps, completely does not overlap, or partially overlaps with the SSB-based measurement timing configuration in the time domain, as shown in fig. 5B, 5A, and 5C, respectively.

Further, CSI-RS resources to be measured may be configured to have a different period than SSB-based measurement timing configuration. For example, the CSI-RS may be configured to have a period of 40ms, while the SSB-based measurement timing configuration is configured to have a period of 20 ms. This may also be referred to as partial overlap, where a portion of the CSI-RS occasions overlap with the SSB-based measurement timing configuration. This is illustrated with reference to fig. 6.

Fig. 6 shows CSI-RS transmissions from a serving cell 601, a first neighboring cell 602, and a second neighboring cell 603. These transmissions occur with a period of 40 ms. In contrast, SSB transmissions 604 available during the allocated SMTC time 605 occur at 20ms periods.

Thus, according to the example of fig. 6, every two SMTC windows are required to measure CSI-RS resources. This means that the measurement of SSB in SMTC #1, #3, #5, etc. will be affected due to CSI-RS resource overlap. However, SSB measurements in smtc#2, #4 … are not interrupted and therefore do not require expansion. The overall CSSF of the SSB may consider the frequency of CSI-RS resources overlapping the SMTC window. The more frequently the CSI-RS resources overlap with SSB-based measurement timing configurations, the more measurement relaxation can be assumed because the longer the expected measurement delay. The problem of how to cope with overlapping SSB and CSI-RS measurement occasions and how to balance these is pending.

Thus, in case the flexible CSI-RS configuration results in too relaxed UE requirements and behavior that reduces system efficiency, the existing CSSF cannot correctly reflect the required measurement period. The following suggests improving CSSF to apply different configuration options related to SSB, associated SSB and CSI-RS measurement requirements.

Various concepts for solving at least one of the above problems are discussed below. In particular, the following aspects are directed to defining SSB-based and CSI-RS-based on-channel measurement requirements to include sharing of measurement resources. A definition of a new CSSF external gap (CSSF _{outside_gap,i_within/outside} _SMTC) for co-channel SSB and CSI-RS based layer three measurements is presented. Furthermore, a new overlap factor F is introduced, which can be used to cope with the additional impact on SSB-based and CSI-RS-based measurements when the CSI-RS resources to be measured at least partly or incompletely overlap SMTC.

The proposed CSSF may be a separate/independent CSSF for CSI-RS based measurements. In other words, the CSSF currently described may be independent of the CSSF defined for SSB-based or associated SSB-based measurements of one measurement object. CSSF _{outside_gap,i_within/outside} _SMTC may be determined taking into account the degree of overlap, i.e., if the time domain position of the CSI-RS resource does not overlap with the SSB-based measurement timing configuration at all, overlaps with the SSB-based measurement timing configuration at part, and/or if some of the CSI-RS opportunities overlap with the SSB-based measurement timing configuration at part when the CSI-RS and SSB-based measurement timing configuration periods are different.

Furthermore, it is proposed hereinafter to classify CSSF for CSI-RS into two types, which may consider the existing principle that non-gap assisted on-channel measurements are performed outside the measurement gap (CSSF _{outside_gap,i}). For example, the first CSSF type may involve CSI-RSs that are outside the gap but that overlap fully, partially, or not fully with SSB-based measurement timing configurations. This type of CSSF may be referred to as CSSF _{outside_gap,i_within_SMTC} (e.g., as in fig. 5B, 5C, and 6). The second CSSF type may involve CSI-RSs that are outside the gap and do not overlap with SMTC at all, i.e., CSSF _{outside_gap,i_outside} _SMTC (e.g., as in fig. 5A).

For example, these definitions may apply in case the UE does not support truly simultaneous parallel measurement and processing of SSB and CSI-RS based measurements.

If the UE supports truly simultaneous parallel measurements of SSB and CSI-RS based measurements, CSSF _{outside_gap,i_within SMTC} may have the same value as CSSF _{outside_gap,i_outside SMTC}, since no shared dedicated searcher/engine is assumed for SSB and CSI-RS based measurements. In this case, the CSSF for SSB and the CSSF for CSI-RS may be independent of each other.

In one option, the measurement values of the CSI-RS may not be spread. Instead, SSB-based measurements may be extended only. Such behavior may be network controlled. Thus, the network may send configuration instructions to the UE and the access network to control this behavior.

Furthermore, if the SSB or associated SSB is not configured, or if the SSB/associated SSB is detected but not measured while the UE is performing CSI-RS based measurements, the CSSF for the SSB may remain unchanged and may not be interrupted by the CSI-RS based measurements, and the CSSF for the CSI-RS may be defined to be the same as the CSSF for the SSB.

Before providing a more general overview again, some specific examples are provided below to illustrate aspects of the presently described mechanisms. It should be understood that the following detailed aspects are non-limiting and are provided to simply illustrate how aspects of the presently described mechanisms may be implemented into a real system. For example, the assumption of CSI-RS configuration is followed that the CSI-RS resource configuration for each layer is within 5ms and 1 CSI-RS period is configured on the layer, and these specific values may depend on the actual implementation in the network.

The first example considers determining CSSF based on the degree of overlap between CSI-RS resources to be measured and SSB-based measurement timing configuration (SMTC).

For the first configuration case, where the CSI-RS based measurements are outside the gap and do not overlap at all with the SSB based measurement timing configuration (fig. 5A), the current CSSF for SSB may remain unchanged (i.e., cssf_ssb=1 in the current definition), while the CSSF for the CSI-RS based measurements may be CSSF _{outside_gap,i_outside SMTC} (i.e., CSSF _{outside_gap,i_outside SMTC} for CSI-RS is 1, i.e., cssf_csi-rs=1). In this case, the measurement of the SSB and the measurement of the CSI-RS are performed without interruption from each other. CSSF for SSB is determined only in consideration of SSB to be measured (including mobility measurements based on SSB and/or measurements of related SSB). The CSSF for CSI-RS is determined only in consideration of CSI-RS to be measured.

For the second configuration case, where the CSI-RS and SSB-based measurement timing configurations are outside the gap and overlap entirely over all SSB-based measurement timing configuration measurement occasions (fig. 5B), CSSF _{outside_gap,i_within SMTC} for both SSB and CSI-RS is determined taking into account both SSB and CSI-RS to be measured. When one SSB layer and one CSI-RS layer are to be measured in one cell, CSSF _{outside_gap,i_within SMTC} for both SSB and CSI-RS may be doubled if fair sharing is applied (e.g. CSI-RS and SSB have the same/fair measurement opportunities, e.g. alternate measurement opportunities CSI-RS, SSB, CSI-RS, SSB … …, etc.). CSSF _{outside_gap,i_outside SMTC} may also be configured by the network. This may be useful, for example, if the network tends to extend SSB and CSI-RS measurements differently. For example, if network preferences minimize disruption to SSB measurements, it may configure larger CSSFs for CSI-RS based measurements, while smaller CSSFs are used for SSB based measurements.

For the third configuration case, where the CSI-RS SSB based measurement timing configuration is outside the gap and the CSI-RS and SSB based measurement timing configurations are partially overlapped (fig. 5C), CSSF for the first configuration case may be applied for SSB and CSI-RS resources outside the partially overlapped region, and CSSF for the second configuration case may be applied for SSB and CSI-RS resources within the partially overlapped region. Alternatively, CSSF _{outside_gap,i_within SMTC} may be the same value as determined in the fully overlapped case, i.e., CSSF _{outside_gap,i_within SMTC}, second configuration case 2, may be applied to the overall CSSF of the third configuration case (i.e., for both overlapped and non-overlapped regions).

For the fourth configuration case, where the CSI-RS and SSB based measurement timing configurations have different periods but occasionally overlap (fig. 6), this case may be referred to as a partially overlapping transmission. To address this problem, an additional scaling factor K may be applied over CSSF _{outside_gap,i} (SSB) and CSSF _{outside_gap,i_within/outside SMTC} (CSI-RS), where they are not interrupted, e.g., the CSSF values in table 1.

The additional scale factor K for each of the SSB measurement delay and the CSI-RS measurement delay may be defined as Ksmtc and Kcsi-RS, respectively, based on the overlap factor F, where f=max (INT (SMTC period/CSI-RS period), INT (CSI-RS period/SMTC period)). This means:

If SMTC period > = CSI-RS period:

F=int (SMTC period, CSI-RS period)

If SMTC period < CSI-RS period:

f=int (CSI-RS period, SMTC period)

Where INT may refer to the actual value of the division (e.g., CSI-RS period divided by SMTC period). INT may alternatively refer to the integer portion of the value.

If fairness extensions are applied, in one option, the additional scale factor K may be determined as follows

If the SMTC period is less than the CSI-RS period (SMTC period < CSI-RS period),

■Kssb＝1+(1/(2*F))

■Kcsi-rs＝min(F,2)。

And if the SMTC period is greater than the CSI-RS period (SMTC > CSI-RS),

■Kssb＝min(2,F),

■Kcsi-rs＝1+(1/(2*F))

In another option, the network may be configured to perform only extended SSB and not extended CSI-RS based measurements. In this option:

■ Kcsi-rs=1 for CSI-RS

■ Kssb =min for SSB (F, 2)

This is illustrated with reference to fig. 7.

Fig. 7 shows CSI-RS transmissions from a serving cell 701, a first neighboring cell 702, and a second neighboring cell 703. These transmissions are made in 20 millisecond periods. In contrast, SSB transmissions 704, which occur within the assigned SMTC time 705, occur at 40ms periods.

In this example, SMTC and CSI-RS periods are configured to be 40ms and 20ms. This gives:

f=int (CSI-RS period, SMTC period) =2.

If a fairness extension is applied,

Kssb＝F＝2。

Kcsi-rs= (1+ (1/(1+2×f))=1.25→cssf=1.25 of CSI-RS.

In contrast, consider the example of FIG. 6, which shows a partially overlapping case, where the SMTC period is 20ms and the CSI-RS period is 40ms, which gives

F＝Mod(CSI-RS,SSB)＝2。

If a fairness extension is applied,

Kssb＝F＝2。

Kcsi-rs＝1+(1/(2*F))＝1.25。

Alternatively, if the network configuration extends only CSI-RS and not SSB-based measurements, SSBs may be measured using a higher priority than CSI-RS when overlapping. In other words:

● Kcsi-rs=f for CSI-RS,

● Kssb =1 for SSB.

Table 3 illustrates how the above aspects are expressed. For simplicity, table 3 considers only FR1 and Primary Component Carrier (PCC). However, it should be understood that this is not limiting.

Table 3 example K values

Wherein:

● If SMTC period > = CSI-RS period:

F=int (SMTC period, CSI-RS period)

● If SMTC < CSI-RS:

f=int (CSI-RS, SMTC period)

In addition to the extensions performed according to the existing requirements, SSB and K/additional extensions based on CSI-RS requirements may also be performed. Thus, "K" may be multiplied by CSSF defined in table 1. Alternatively, the scaling factor K may be directly included in the CSSF table defined for SSB and CSI-RS.

The scaling factor K of FR2 can be developed in a similar manner as FR1 described above.

Fig. 8 is a flow chart illustrating potential operations that may be performed by an apparatus as described herein. The apparatus may be a terminal, such as a user equipment, that measures at least one downlink reference signal.

Hereinafter, reference is made to signal availability/availability of signals, these terms being used interchangeably. A signal may be considered to be available within a time frame if the signal is configured to be provided within the time frame. For example, a signal may be considered available if it is available for transmission and/or reception within the time frame.

At 801, the apparatus determines a first scale factor for determining a first measurement delay for measuring a first type of reference signal. The first scale factor may be a CSSF for the first type of reference signal. The first type of reference signal may be a CSI-RS.

At 802, the apparatus determines a second scale factor for determining a second measurement delay for measuring a second type of reference signal. The second scale factor may be a CSSF for the second type of reference signal. The second type of reference signal may be SSB.

At 803, the apparatus determines a first measured delay and a second measured delay. The first measurement delay may be a maximum time (or additional time) that allows measurements to be performed on the first type of reference signal. The second measurement delay may be a maximum time (or additional time) that allows measurements to be performed on the second type of reference signal.

At 804, the apparatus uses the first measurement delay and the second measurement delay for respective time periods for measuring the first type of reference signal and the second type of reference signal. In particular, the apparatus may determine a time period for performing measurements on the first type of reference signal using the determined first measurement delay and perform measurements on the first type of reference signal within the determined time period. Further, the apparatus may determine a time period for measuring the second type of reference signal using the determined second measurement delay and measure the second type of reference signal for the determined time period.

Determining the first scale factor may include: determining a degree of overlap between the availability of the first type of reference signal and the availability of the second type of reference signal; and determining a first scale factor based on the degree of overlap. For example, there may be no overlap (as described above with respect to fig. 5A), there may be complete overlap (as described above with respect to fig. 5B), there may be partial overlap (as described above with respect to fig. 5C), and there may be incomplete overlap (as described above with respect to fig. 6).

When the determined degree of overlap indicates that the first type of reference signal and the second type of reference signal do not overlap in time, the first scale factor and the second scale factor may be determined independently of each other. This may be as described above with reference to fig. 5A. In this case, both the first scale factor and the second scale factor may be 1.

The first scaling factor and the second scaling factor may be determined interdependently when the determined degree of overlap indicates that the first type of reference signal and the second type of reference signal at least partially overlap in time. This may be as described above with respect to fig. 5B, 5C and 6.

When the determined degree of overlap may indicate that the first type of reference signal and the second type of reference signal are at least partially overlapping in time relative to the first type of reference signal, the values of the first scale factor and the second scale factor are twice the values of the first scale factor and the second scale factor.

When the determined degree of overlap indicates that the first type of reference signal and the second type of reference signal partially overlap in time, the first scale factor may include a primary additional scale factor and the second scale factor may include a secondary additional scale factor. In other words, when the determined degree of overlap is generated by periods of the opposing first and second reference signals, the first scale factor may include a primary additional scale factor and the second scale factor may include a secondary additional scale factor.

In other words, the first scale factor may include an additional scale factor (and be similar for the second scale factor) when the determined degree of overlap is produced by periods of the opposing first and second reference signals. The additional scale factor may be as described above with reference to "k". Determining the additional scale factor may include: determining a primary scale factor for determining a first measured delay; a secondary scale factor is determined for determining the first measured delay, wherein the primary scale factor and the secondary scale factor are determined based on the transmission period of the first type of signal and the transmission period of the second type of signal.

The additional scale factor may be determined by calculating the overlap factor F. This may be as described above. In other words:

f=max (INT (second type transmission period/first type transmission period), INT (first type transmission period/second type transmission period)).

The first scaling factor and the second scaling factor may have different respective values. For example, the first scale factor may have a value equal to 1 and the second scale factor may have a value not equal to 1. As another example, the first scale factor may have a value that is not equal to 1, and the second scale factor may have a value that is equal to 1.

The presently described technology has several advantages. For example, the presently described techniques determine UE measurement requirements for SSB-based and CSI-RS-based measurements, and further enable determination of UE measurement requirements when CSI-RS resources are configured for layer three measurements other than SSB-based. Considering the entire CSI-RS layer to be measured, explicit UE measurement requirements may be defined.

Fig. 2 shows an example of a control means for a communication system, e.g. a station such as a RAN node (e.g. a base station, a gNB, a central unit of a cloud architecture or a node of a core network such as an MME or S-GW, a scheduling entity such as a spectrum management entity, or a server or host, e.g. hosting device NRF, NWDAF, AMF, SMF, UDM/UDR, etc.) coupled to and/or for controlling an access system. The control means may be integrated with the nodes or modules of the core network or RAN, or may be external. In some embodiments, the base station includes a separate control device unit or module. In other embodiments, the control device may be other network elements such as a radio network controller or a spectrum controller. The control means 200 may be arranged to provide control of the communication in the service area of the system. The apparatus 200 comprises at least one memory 201, at least one data processing unit 202, 203 and an input/output interface 204. Via the interface, the control device may be coupled to a receiver and a transmitter of the device. The receiver and/or transmitter may be implemented as a radio front-end or a remote radio head. For example, the control device 200 or the processor 201 may be configured to execute appropriate software code to provide control functions.

A possible wireless communication device will now be described in more detail with reference to fig. 3, fig. 3 showing a schematic partial cross-sectional view of a communication device 300. Such communication devices are often referred to as User Equipment (UE) or terminals. A suitable mobile communication device may be provided by any device capable of transmitting and receiving radio signals. Non-limiting examples include: a Mobile Station (MS) or a mobile device such as a mobile phone or a so-called "smart phone"; a computer equipped with a wireless interface card or other wireless interface facility (e.g., a USB dongle); a Personal Digital Assistant (PDA) or a tablet computer with wireless communication function; or any combination of these devices, etc. A mobile communication device may provide, for example, data communications for carrying communications such as voice, electronic mail (email), text messages, multimedia, and the like. A large number of services can be provided and offered to users via their communication devices. Non-limiting examples of such services include two-way or multi-way calls, data communication or multimedia services, or simply accessing a data communication network system, such as the internet. Broadcast or multicast data may also be provided to the user. Non-limiting examples of content include downloads, television and radio programming, video, advertising, various alerts, and other information.

The wireless communication device may be, for example, a mobile device, i.e., a device that is not fixed to a particular location, or it may be a fixed device. The wireless device may or may not require human-machine interaction to communicate. In the present teachings, the term UE or "user" is used to refer to any type of wireless communication device.

The wireless device 300 may receive signals over the air or radio interface 307 via suitable means for receiving and may transmit signals via suitable means for transmitting radio signals. In fig. 3, the transceiver device is schematically designated by block 306. The transceiver means 306 may be provided, for example, by means of a radio and an associated antenna arrangement. The antenna arrangement may be arranged inside or outside the wireless device.

The wireless device is typically provided with at least one data processing entity 301, at least one memory 302 and other possible means 303 for software and hardware assisted execution of tasks it is designed to perform, including access to and control of communication with access systems and other communication devices. The data processing, storage and other associated control means may be provided on a suitable circuit board and/or in a chipset. This feature is indicated by reference numeral 704. The user may control the operation of the wireless device by means of a suitable user interface such as a keyboard 305, voice commands, touch sensitive screen or panel, combinations thereof, or the like. A display 308, speakers, and microphone may also be provided. Further, the wireless communication device may include suitable connectors (wired or wireless) to other devices and/or for connecting external accessories, such as hands-free devices.

Fig. 4 shows a schematic diagram of non-volatile storage media 400a (e.g., a Computer Disk (CD) or a Digital Versatile Disk (DVD)) and 400b (e.g., a Universal Serial Bus (USB) memory stick) storing instructions and/or parameters 402 that, when executed by a processor, allow the processor to perform one or more steps of the method of fig. 10.

The embodiments may thus vary within the scope of the attached claims. Generally, some may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. . For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the embodiments are not limited thereto. While various embodiments may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The embodiments may be implemented by computer software stored in a memory and executed by at least one data processor of the relevant entity or hardware, or by a combination of software and hardware. It should further be noted in this regard that any process in fig. 10, for example, may represent a procedure step, or interconnected logic circuits, blocks and functions, or a combination of procedure steps and logic circuits, blocks and functions. The software may be stored on a physical medium such as a memory chip or a memory block implemented in a processor, a magnetic medium such as a hard disk or floppy disk, and an optical medium such as, for example, a DVD and data variants thereof, a CD.

The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processor may be of any type suitable to the local technical environment and may include one or more of a general purpose computer, a special purpose computer, a microprocessor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a gate level circuit, and a processor based on a multi-core processor architecture, as non-limiting examples.

Alternatively or additionally, some embodiments may be implemented using circuitry. The circuitry may be configured to perform one or more of the functions and/or method steps described previously. The circuitry may be provided in the base station and/or the communication device.

As used in this disclosure, the term "circuit" may refer to one or more or all of the following:

(a) Hardware-only circuit implementations (such as implementations in analog and/or digital circuits only);

(b) A combination of hardware circuitry and software, for example:

(i) Combination of analog and/or digital hardware circuitry and software/firmware, and

(Ii) Any portion of a hardware processor having software (including a digital signal processor), software, and memory that work together to cause a device, such as a communication device or a base station, to perform the various functions previously described; and

(C) Hardware circuitry and/or a processor, such as a microprocessor or a portion of a microprocessor, requires software (e.g., firmware) to operate, but when operation is not required, the software may not be present.

This circuit definition applies to all uses of this term in this application, including in any claims. As a further example, as used in this disclosure, the term circuitry also encompasses hardware-only circuitry or processor (or processors) or a portion of hardware circuitry or processor and its (or their) accompanying software and/or firmware implementations. The term circuit also covers, for example, integrated devices.

The foregoing description has provided by way of exemplary and non-limiting examples a complete and informative description of some embodiments. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings will still fall within the scope defined by the appended claims.

Claims

1. A method for communication, the method comprising:

determining a first scale factor for determining a first measurement delay for measuring a first type of reference signal;

determining a second scale factor for determining a second measurement delay for measuring a second type of reference signal;

determining the first measured delay and the second measured delay; and

The first measurement delay and the second measurement delay are used for a period of time during which measurements of the first type of reference signal and the second type of reference signal are performed.

2. The method of claim 1, wherein the first type of reference signal is a channel state information reference signal and the second type of reference signal is a synchronization signal block.

3. The method of any of the preceding claims, wherein the first and second scaling factors are carrier specific scaling factors.

4. The method of any of the preceding claims, wherein determining the first scale factor and the second scale factor comprises:

Determining a degree of overlap between the first type of reference signal and the second type of reference signal; and

The first scale factor and the second scale factor are determined according to the degree of overlap.

5. The method of claim 4, wherein the first scale factor and the second scale factor are determined independently of each other when the determined degree of overlap indicates that the first type of reference signal and the second type of reference signal do not overlap in time.

6. The method of claim 4, wherein the first scale factor and the second scale factor are determined interdependently when the determined degree of overlap indicates that the first type of reference signal and the second type of reference signal at least partially overlap in time.

7. The method of claim 6, wherein when the determined degree of overlap indicates that the first type of reference signal and the second type of reference signal partially or fully coincide in time:

The value of the first scale factor is twice the value the first scale factor has when the first type reference signal and the second type reference signal do not overlap in time; and the second scale factor has a value twice that of the second scale factor when the first type reference signal and the second type reference signal do not overlap in time.

8. The method of any of claims 6 to 7, wherein the first scale factor comprises a primary additional scale factor and the second scale factor comprises a secondary additional scale factor when the determined degree of overlap indicates that the first type of reference signal and the second type of reference signal partially overlap in time.

9. The method of claim 4, wherein the first scale factor comprises a primary additional scale factor and the second scale factor comprises a secondary additional scale factor when the determined degree of overlap is produced by periods of opposing first and second reference signals.

10. The method of any one of claims 8 and 9, further comprising: determining the primary additional scale factor and the secondary additional scale factor, the determining the primary additional scale factor and the secondary additional scale factor comprising:

Determining the primary additional scale factor; and

Determining the auxiliary additional scale factor;

wherein the primary and secondary additional scale factors are determined from an availability period of the first type of reference signal and an availability period of the second type of reference signal.

11. The method of any of claims 8 to 10, wherein the additional scale factor is determined by calculating an overlap factor F, wherein:

Where INT is the exact division value or integer part of the division value.

12. The method of claim 4, wherein the first scale factor is determined to be higher when the availability of the first type of reference signal is at least partially overlapping in time with the availability of the second type of reference signal than when the availability of the first type of reference signal is not overlapping in time with the availability of the second type of reference signal.

13. The method of any of claims 1 to 4, wherein the first scale factor is 1 and the second scale factor is not equal to 1.

14. The method of any of claims 1 to 4, wherein the first scale factor is not equal to 1 and the second scale factor is equal to 1.

15. An apparatus for communication, the 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 to, with the at least one processor, cause the apparatus at least to perform:

determining the first measured delay and the second measured delay; and

The first measurement delay and the second measurement delay are used for a period of time in which measurements of the first type of reference signal and the second type of reference signal are performed.

16. The apparatus of claim 15, wherein the first type of reference signal is a channel state information reference signal and the second type of reference signal is a synchronization signal block.

17. The apparatus of any of claims 15-16, wherein the first and second scaling factors are carrier-specific scaling factors.

18. The apparatus of any of claims 15-17, wherein determining the first scale factor and the second scale factor comprises:

19. The apparatus of claim 18, wherein the first scaling factor and the second scaling factor are determined independently of each other when the determined degree of overlap indicates that the first type of reference signal and the second type of reference signal do not overlap in time.

20. The apparatus of claim 18, wherein the first scaling factor and the second scaling factor are determined interdependently when the determined degree of overlap indicates that the first type of reference signal and the second type of reference signal at least partially overlap in time.

21. The apparatus of claim 20, wherein when the determined degree of overlap indicates that the first type of reference signal and the second type of reference signal partially or fully overlap in time:

The value of the first scale factor is twice the value the first scale factor has when the first type reference signal and the second type reference signal do not overlap in time; and

The second scale factor has a value twice that of the second scale factor when the first type reference signal and the second type reference signal are not coincident in time.

22. The apparatus of any of claims 20-21, wherein the first scale factor comprises a primary additional scale factor and the second scale factor comprises a secondary additional scale factor when the determined degree of overlap indicates that the first type of reference signal and the second type of reference signal partially overlap in time.

23. The apparatus of claim 18, wherein the first scale factor comprises a primary additional scale factor and the second scale factor comprises a secondary additional scale factor when the determined degree of overlap is generated by periods of opposing first and second reference signals.

24. The apparatus of any one of claims 22 and 23, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to perform: determining the primary additional scale factor and the secondary additional scale factor, the determining the primary additional scale factor and the secondary additional scale factor comprising:

Determining the primary additional scale factor; and

Determining the auxiliary additional scale factor;

25. The apparatus of any of claims 22-24, wherein the additional scale factor is determined by calculating an overlap factor F, wherein:

Where INT is the exact division value or integer part of the division value.

26. The apparatus of claim 18, wherein the first scale factor is determined to be higher when the availability of the first type of reference signal is at least partially overlapping in time with the availability of the second type of reference signal than when the availability of the first type of reference signal is not overlapping in time with the availability of the second type of reference signal.

27. The apparatus of any of claims 15-18, wherein the first scale factor is 1 and the second scale factor is not equal to 1.

28. The apparatus of any of claims 15-18, wherein the first scale factor is not equal to 1 and the second scale factor is equal to 1.

29. A computer readable medium comprising program instructions which, when run on at least one processor of an apparatus, cause the apparatus to perform:

determining the first measured delay and the second measured delay; and