Patent Description:
With a continuous increasing of global smartphone users, mobile data usage and traffic will continue to grow. In New Radio, dual connectivity (DC) are proposed to allow a wireless communication device with multiple transceivers to simultaneously receive data packet from at least two wireless communication nodes, for example a Master gNodeB (MgNB) and a secondary gNodeB (SgNB). In New Radio, a wireless communication device can perform measurement on intra-frequency, inter-frequency and inter-RAT (Radio Access Technology) frequencies. This frequency measurement by the wireless communication device is configured by a Master gNodeB and/or a Secondary gNodeB in order to facilitate mobility management or other radio resource management functions. Document 3GPP DRAFT R2-<NUM> relates to measurement and gap configuration framework in NR-E-UTRA DC (NE-DC). Document 3GPP DRAFT R2-<NUM> relates to measurement and gap configuration framework in NG-RAN E-UTRA-NR DC (NGEN DC). Document 3GPP DRAFT R1-<NUM> relates to measurement configuration for NR-NR DC. Document 3GPP TS <NUM> V15. <NUM> relates to Radio Resource Control protocol for the radio interface between UE and NG-RAN.

The exemplary embodiments disclosed herein are directed to solving the issues related to one or more problems presented in the prior art, as well as providing additional features that will become readily apparent by reference to the following detailed description when taken in conjunction with the accompany drawings. In accordance with various embodiments, exemplary systems, methods, and computer program products are disclosed herein. It is understood, however, that these embodiments are presented by way of example and not limitation, and it will be apparent to those of ordinary skill in the art who read the present disclosure that various modifications to the disclosed embodiments can be made while remaining within the scope of the invention as defined by the appended claims.

In LTE dual connectivity (DC), a wireless communication device (UE) may have multiple serving cells belong to different wireless communication nodes (eNBs) which are known as primary eNB (MeNB) and secondary eNB (SeNB), and the primary cell in MeNB is named as PCell and the primary cell in SeNB is named as PSCell. In LTE specification, only MeNB can configure and manage frequency measurements for the UE. When a measured frequency by the UE and a serving cell belong to a same RAT (e.g. LTE), wherein the measured frequency has the same center frequency as a frequency of one of the UE's serving cells from both the MeNB and the SeNB, the frequency is known as "intra-frequency" and a frequency measurement task performed by the UE is an "intra-frequency measurement". Accordingly, an index of the intra-frequency measurement task is used as an inter-frequency measurement identity. Similarly, when the measured frequency has different center frequency from any one of the UE's serving cells, the frequency is known as "inter-frequency" and the frequency measurement task is an "inter-frequency measurement". Similarly, an index of the inter-frequency measurement task is used as an inter-frequency measurement identity. When the frequency belongs to a different RAT, it is called "inter-RAT measurement". Since only MeNB can conduct measurements configuration, it is simple for MeNB to ensure a maximum number of measured frequency layers and a maximum number of frequency measurement identities are within the capability of the UE, e.g., a maximum number of frequency layers that can be measured by the UE or a maximum number of frequency measurement identities.

In new radio (NR) system, a similar DC architecture can be also introduced. In NR-DC, a UE can connect to multiple NR nodes (gNodeB or gNB) including at least one master gNB (MgNB) and at least one secondary gNB (SgNB). Serving cells within one of the at least one MgNB are grouped together to form a Master Cell Group (MCG), and serving cells within one of the at least one SgNB are grouped together to form a Secondary Cell Group (SCG). Different from LTE, each of the at least one SgNB in NR-DC is allowed to configure frequency measurement and transmits a configuration of a frequency measurement directly to the UE. For example, when a signal radio bearer over a SgNB and a UE is already established, the configuration of the frequency measurement can be transmitted to the UE via the signal radio bearer directly. For another example, when a signal radio bearer is not established, a configuration of the frequency measurement can be delivered directly from a respective MgNB to the UE. The frequency measurements configured by the at least one SgNB and the at least one MgNB to the UE are required to be coordinated to ensure the configuration (e.g., total number of configured frequency measurement identities) is within the capability of the UE.

Furthermore, in NR DC, an MgNB is also responsible for configuring all types of gap patterns. However, the UE may acquire different synchronization timing from different serving cells of different gNodeBs, a gap calculation in the time domain based on just the gap pattern received from the MgNB is ambiguous and extra interruption of data scheduling is required. Therefore, there exists a need to develop a method and apparatus for accurately configuring frequency measurement and reference timing for gap calculation in New Radio with dual connectivity.

In one embodiment, a method for configuring a frequency measurement by a first wireless communication node, includes: transmitting a first message to a second wireless communication node, wherein the first message comprises at least one of the following: a first maximum number of allowed intra-frequency measurement identities and a first maximum number of allowed inter-frequency measurement identities, and wherein the first message is used by the by the second wireless communication node to determine a first configuration of the frequency measurement for a wireless communication device.

In a further embodiment, a method for configuring a frequency measurement by a first wireless communication node, includes: receiving a first message from a second wireless communication node, and determining a first configuration of the frequency measurement for a wireless communication device according to the first message, wherein the first message comprises at least one of the following: a first maximum number of allowed intra-frequency measurement identities and a first maximum number of allowed inter-frequency measurement identities.

In a further embodiment, a method for determining a type of a frequency measurement by a first wireless communication node, includes: transmitting a first message to a second wireless communication node, wherein the first message comprises frequency information of all first serving cells of the first wireless communication node, and wherein the frequency information of all first serving cells of the first wireless communication node is used by the second wireless communication node together with frequency information of all second serving cells of the second wireless communication node to determine the type of the frequency measurement.

In a further embodiment, method for determining a type of a frequency measurement by a first wireless communication node, includes: receiving a first message from a second wireless communication node, wherein the first message comprises frequency information of all first serving cells of the second wireless communication node; and determining the type of the frequency measurement according to at least one of the following: the frequency information of all the first serving cells of the second wireless communication node in the first message and frequency information of all second serving cells of the first wireless communication node.

Yet in another embodiment, a computing device comprising at least one processor and a memory coupled to the processor, the at least one processor configured to carry out the method.

Yet, in another embodiment, a non-transitory computer-readable medium having stored thereon computer-executable instructions for carrying out the method.

It is noted that various features are not necessarily drawn to scale. In fact, the dimensions and geometries of the various features may be arbitrarily increased or reduced for clarity of discussion.

Various exemplary embodiments of the invention are described below with reference to the accompanying figures to enable a person of ordinary skill in the art to make and use the invention. As would be apparent to those of ordinary skill in the art, after reading the present disclosure, various changes or modifications to the examples described herein can be made without departing from the scope of the invention, solely defined by the appended claims.

Thus, the present invention is not limited to the exemplary embodiments and applications described or illustrated herein.

Embodiments of the present invention are described in detail with reference to the accompanying drawings. The same or similar components may be designated by the same or similar reference numerals although they are illustrated in different drawings. Detailed descriptions of constructions or processes well-known in the art may be omitted to avoid obscuring the subject matter of the present invention. Further, the terms are defined in consideration of their functionality in embodiment of the present invention, and may vary according to the intention of a user or an operator, usage, etc. Therefore, the definition should be made on the basis of the overall content of the present specification.

<FIG> illustrates an exemplary wireless communication network <NUM>, in accordance with some embodiments of the present disclosure. In a wireless communication system, a network side communication node or a base station (BS) <NUM> can be a node B, an E-UTRA Node B (also known as Evolved Node B, eNodeB or eNB), a gNodeB (also known as gNB) in new radio (NR) technology, a pico station, a femto station, or the like. A terminal side communication device or a user equipment (UE) <NUM> can be a long range communication system like a mobile phone, a smart phone, a personal digital assistant (PDA), tablet, laptop computer, or a short range communication system such as, for example a wearable device, a vehicle with a vehicular communication system and the like. A network communication node and a terminal side communication device are represented by a BS <NUM> and a UE <NUM>, respectively, and in all the embodiments in this disclosure hereafter, and are generally referred to as "communication nodes" and "communication device" herein. Such communication nodes and communication devices may be capable of wireless and/or wired communications, in accordance with various embodiments of the invention. It is noted that all the embodiments are merely preferred examples, and are not intended to limit the present disclosure. Accordingly, it is understood that the system may include any desired combination of BSs <NUM> and UEs <NUM>.

Referring to <FIG>, the wireless communication network <NUM> includes a first BS <NUM>-<NUM>, a second BS <NUM>-<NUM>, and a UE <NUM>. In some embodiments, the UE <NUM> forms direct communication (i.e., uplink) channels <NUM>-<NUM> and <NUM>-<NUM> with the first BS <NUM>-<NUM> and the second BS <NUM>-<NUM>, respectively. In some embodiments, the UE <NUM> also forms direct communication (i.e., downlink) channels <NUM>-<NUM> and <NUM>-<NUM> with the first BS <NUM>-<NUM> and the second BS <NUM>-<NUM>, respectively. The direct communication channels between the UE <NUM> and the BS <NUM> can be through interfaces such as an Uu interface, which is also known as E-UTRA air interface. In some embodiments, the UE <NUM> comprises a plurality of transceivers which enables the UE <NUM> to support dual connectivity so as to receive data simultaneously from the first BS <NUM>-<NUM> and the second BS <NUM>-<NUM>. The first and second BS <NUM>-<NUM> and <NUM>-<NUM> each is connected to a core network (CN) <NUM> through an external interface <NUM>, e.g., an Iu interface, or an NG interface. In some other embodiment, the first BS <NUM>-<NUM> (gNB) is a Master Node (MN), which is connected to the CN <NUM> and the second BS <NUM>-<NUM> (gNB) is a Secondary Node (SN), which is also connected to the CN <NUM>.

In some other embodiments, when the first BS <NUM>-<NUM> and the second BS <NUM>-<NUM> each is a gNB, the direct communication between the first BS <NUM>-<NUM> and the second BS <NUM>-<NUM> is through an Xn interface. The first BS <NUM>-<NUM> and the second BS <NUM>-<NUM> are neighboring BSs. A first serving cell <NUM>-<NUM> is covered by the first BS <NUM>-<NUM> and the second serving cell <NUM>-<NUM> is covered by the second BS <NUM>-<NUM>. In some embodiments, the first cell <NUM>-<NUM> is a primary cell of the MN, known as PCell, and the second cell <NUM>-<NUM> is a primary cell of the SN, known as PSCell. In some embodiments, the first cell <NUM>-<NUM> and the second cell <NUM>-<NUM> are neighboring cells.

<FIG> illustrates a block diagram of an exemplary wireless communication system <NUM>, in accordance with some embodiments of the present disclosure. The system <NUM> may include components and elements configured to support known or conventional operating features that need not be described in detail herein. In some embodiments, the system <NUM> can be used to transmit and receive data symbols in a wireless communication environment such as the wireless communication network <NUM> of <FIG>, as described above.

The system <NUM> generally includes a first BS <NUM>-<NUM>, a second <NUM>-<NUM>, and a UE <NUM>, collectively referred to as BS <NUM> and UE <NUM> below for ease of discussion. The first BS <NUM>-<NUM> and the second BS <NUM>-<NUM> each comprises a BS transceiver module <NUM>, a BS antenna array <NUM>, a BS memory module <NUM>, a BS processor module <NUM>, and a network interface <NUM>. In the illustrated embodiment, each module of the BS <NUM> are coupled and interconnected with one another as necessary via a data communication bus <NUM>. The UE <NUM> comprises a UE transceiver module <NUM>, a UE antenna <NUM>, a UE memory module <NUM>, a UE processor module <NUM>, and an I/O interface <NUM>. In the illustrated embodiment, each module of the UE <NUM> are coupled and interconnected with one another as necessary via a date communication bus <NUM>. The BS <NUM> communicates with the UE <NUM> via a communication channel <NUM>, which can be any wireless channel or other medium known in the art suitable for transmission of data as described herein.

As would be understood by persons of ordinary skill in the art, the system <NUM> may further include any number of modules other than the modules shown in <FIG>.

A wireless transmission from a transmitting antenna of the UE <NUM> to a receiving antenna of the BS <NUM> is known as an uplink (UL) transmission, and a wireless transmission from a transmitting antenna of the BS <NUM> to a receiving antenna of the UE <NUM> is known as a downlink (DL) transmission. In accordance with some embodiments, the UE transceiver <NUM> may be referred to herein as an "uplink" transceiver <NUM> that includes a RF transmitter and receiver circuitry that are each coupled to the UE antenna <NUM>. Similarly, in accordance with some embodiments, the BS transceiver <NUM> may be referred to herein as a "downlink" transceiver <NUM> that includes RF transmitter and receiver circuitry that are each coupled to the antenna array <NUM>. A downlink duplex switch may alternatively couple the downlink transmitter or receiver to the downlink antenna array <NUM> in time duplex fashion. The operations of the two transceivers <NUM> and <NUM> are coordinated in time such that the uplink receiver is coupled to the uplink UE antenna <NUM> for reception of transmissions over the wireless communication channel <NUM> at the same time that the downlink transmitter is coupled to the downlink antenna array <NUM>. Preferably, there is close synchronization timing with only a minimal guard time between changes in duplex direction. The UE transceiver <NUM> communicates through the UE antenna <NUM> with the BS <NUM> via the wireless communication channel <NUM>. The BS transceiver <NUM> communications through the BS antenna <NUM> of a BS (e.g., the first BS <NUM>-<NUM>) with the other BS (e.g., the second BS <NUM>-<NUM>) via a wireless communication channel <NUM>. The wireless communication channel <NUM> can be any wireless channel or other medium known in the art suitable for direct communication between BSs.

The UE transceiver <NUM> and the BS transceiver <NUM> are configured to communicate via the wireless data communication channel <NUM>, and cooperate with a suitably configured RF antenna arrangement <NUM>/<NUM> that can support a particular wireless communication protocol and modulation scheme. In some exemplary embodiments, the UE transceiver <NUM> and the BS transceiver <NUM> are configured to support industry standards such as the Long Term Evolution (LTE) and emerging <NUM> standards (e.g., NR), and the like. It is understood, however, that the invention is not necessarily limited in application to a particular standard and associated protocols. Rather, the UE transceiver <NUM> and the BS transceiver <NUM> may be configured to support alternate, or additional, wireless data communication protocols, including future standards or variations thereof.

The processor modules <NUM> and <NUM> may be implemented, or realized, with a general purpose processor, a content addressable memory, a digital signal processor, an application specific integrated circuit, a field programmable gate array, any suitable programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. In this manner, a processor module may be realized as a microprocessor, a controller, a microcontroller, a state machine, or the like. A processor module may also be implemented as a combination of computing devices, e.g., a combination of a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a digital signal processor core, or any other such configuration.

In this regard, the memory modules <NUM> and <NUM> may be coupled to the processor modules <NUM> and <NUM>, respectively, such that the processors modules <NUM> and <NUM> can read information from, and write information to, memory modules <NUM> and <NUM>, respectively. The memory modules <NUM> and <NUM> may also each include non-volatile memory for storing instructions to be executed by the processor modules <NUM> and <NUM>, respectively.

The network interface <NUM> generally represents the hardware, software, firmware, processing logic, and/or other components of the base station <NUM> that enable bi-directional communication between BS transceiver <NUM> and other network components and communication nodes configured to communication with the BS <NUM>. For example, network interface <NUM> may be configured to support internet or WiMAX traffic. In a typical deployment, without limitation, network interface <NUM> provides an <NUM> Ethernet interface such that BS transceiver <NUM> can communicate with a conventional Ethernet based computer network. In this manner, the network interface <NUM> may include a physical interface for connection to the computer network (e.g., Mobile Switching Center (MSC)). The terms "configured for" or "configured to" as used herein with respect to a specified operation or function refers to a device, component, circuit, structure, machine, signal, etc. that is physically constructed, programmed, formatted and/or arranged to perform the specified operation or function. The network interface <NUM> could allow the BS <NUM> to communicate with other BSs or a CN over a wired or wireless connection.

Referring again to <FIG>, as mentioned above, the BS <NUM> repeatedly broadcasts system information associated with the BS <NUM> to one or more UEs <NUM> so as to allow the UEs <NUM> to access the network within the cells (e.g., <NUM>-<NUM> for the first BS <NUM>-<NUM> and <NUM>-<NUM> for the second BS <NUM>-<NUM>) where the BS <NUM> is located, and in general, to operate properly within the cell. Plural information such as, for example, downlink and uplink cell bandwidths, downlink and uplink configuration, cell information, configuration for random access, etc., can be included in the system information, which will be discussed in further detail below. Typically, the BS <NUM> broadcasts a first signal carrying some major system information, for example, configuration of the cell <NUM> through a PBCH (Physical Broadcast Channel). For purposes of clarity of illustration, such a broadcasted first signal is herein referred to as "first broadcast signal. " It is noted that the BS <NUM> may subsequently broadcast one or more signals carrying some other system information through respective channels (e.g., a Physical Downlink Shared Channel (PDSCH)).

Referring again to <FIG>, in some embodiments, the major system information carried by the first broadcast signal may be transmitted by the BS <NUM> in a symbol format via the communication channel <NUM> (e.g., a PBCH). In accordance with some embodiments, an original form of the major system information may be presented as one or more sequences of digital bits and the one or more sequences of digital bits may be processed through plural steps (e.g., coding, scrambling, modulation, mapping steps, etc.), all of which can be processed by the BS processor module <NUM>, to become the first broadcast signal. Similarly, when the UE <NUM> receives the first broadcast signal (in the symbol format) using the UE transceiver <NUM>, in accordance with some embodiments, the UE processor module <NUM> may perform plural steps (de-mapping, demodulation, decoding steps, etc.) to estimate the major system information such as, for example, bit locations, bit numbers, etc., of the bits of the major system information. The UE processor module <NUM> is also coupled to the I/O interface <NUM>, which provides the UE <NUM> with the ability to connect to other devices such as computers. The I/O interface <NUM> is the communication path between these accessories and the UE processor module <NUM>.

<FIG> illustrates a method <NUM> for configuring a frequency measurement, in accordance with some embodiments of the present disclosure. It is understood that additional operations may be provided before, during, and after the method <NUM> of <FIG>, and that some operations may be omitted or reordered. The communication system in the illustrated embodiment comprises a first BS <NUM>-<NUM>, and a second BS <NUM>-<NUM>. In the illustrated embodiments, a UE <NUM> (not shown) is in one of at least one serving cell covered by the first BS <NUM>-<NUM> and also in one of at least one serving cell covered by the second BS <NUM>-<NUM>, i.e., the UE <NUM> is in connection with the first BS <NUM>-<NUM> and the second BS <NUM>-<NUM>. In some embodiments, the first BS <NUM>-<NUM> is a primary wireless communication node and the second BS <NUM>-<NUM> is a secondary wireless communication node. In some other embodiments, the second BS <NUM>-<NUM> is a primary wireless communication node and the first BS <NUM>-<NUM> is a secondary wireless communication node. It should be noted that any numbers of BS <NUM> can be used.

The method <NUM> starts with operation <NUM> in which the first BS <NUM>-<NUM> transmits a first message to the second BS <NUM>-<NUM> according to some embodiments. In some embodiments, the first message comprises frequency information of all serving cells of the first BS <NUM>-<NUM>. In some embodiments, the first message is transmitted from the first BS <NUM>-<NUM> to the second BS <NUM>-<NUM> through a UE-specific inter-node RRC (Radio Resource Control) message (e.g., CG-ConfigInfo). In some embodiments, the first message is transmitted during an addition or a modification process to the second BS <NUM>-<NUM>. In some embodiments, the frequency information of all the serving cells of the first BS <NUM>-<NUM> comprises at least one of the following: frequency information of synchronization signal blocks (SSB) of the respective serving cells, and frequency information of channel state information reference signals (CSI-RS) of the respective serving cells. In some embodiments, the frequency information of the SSBs of the respective serving cells comprises at least one of the following of a SSB: a center frequency, a subcarrier spacing, and a band indicator. In some embodiments, the frequency information of CSI-RSs of the respective serving cells comprises at least one of the following of a CSI-RS: a start position in the frequency domain, a frequency offset, and a frequency bandwidth.

For example, the first BS <NUM>-<NUM> comprises a first serving cell with a first center frequency and a second serving cell with a second center frequency. The second BS <NUM>-<NUM> comprises a third serving cell with a third center frequency and a fourth serving cell with a fourth center frequency. During an addition or a modification process to the second BS <NUM>-<NUM>, the first BS <NUM>-<NUM> transmits a first message to the second BS <NUM>-<NUM> so as to indicate frequency information (e.g., the first center frequency and the second center frequency) of the first serving cell and the second serving cell, respectively, to the second BS <NUM>-<NUM> through an inter-node RRC message (e.g., CG-ConfigInfo).

For another example, the first BS <NUM>-<NUM> comprises a first serving cell with a first SSB with a first center frequency. The first BS <NUM>-<NUM> also comprises a second serving cell with a CSI-RS with a first starting frequency and a first bandwidth. The second BS <NUM>-<NUM> comprises a second serving cell with a second SSB with a second center frequency. During an addition or a modification process to the second BS <NUM>-<NUM>, the first BS <NUM>-<NUM> transmits a first message to the second BS <NUM>-<NUM> so as to indicate frequency information (e.g., the first center frequency, the first starting frequency, and the first bandwidth) of the first serving cell and the second serving cell, respectively, to the second BS <NUM>-<NUM> through an inter-node RRC message (e.g., CG-ConfigInfo).

In some embodiments, the first message can be received by the first BS <NUM>-<NUM> from the second BS <NUM>-<NUM>. In some embodiments, the first message comprises frequency information of serving cells of the second BS <NUM>-<NUM>. In some embodiments, the first message received from the second BS <NUM>-<NUM> by the first BS <NUM>-<NUM> is through an inter-node RRC message (e.g., CG-Config).

The method <NUM> continues with operation <NUM> in which the second BS <NUM>-<NUM> determines the type of frequency measurement according to some embodiments. In some embodiments, the second BS <NUM>-<NUM> determine the type of frequency measurement by comparing frequency information (e.g., a frequency set) of all serving cells and a measurement frequency.

For example, when the second BS <NUM>-<NUM> receives the frequency information (e.g., the first center frequency and the second center frequency) from the first BS <NUM>-<NUM>, the frequency information of all the serving cells of the UE <NUM> is available to the second BS <NUM>-<NUM>. When the second BS <NUM>-<NUM> configures a SSB-based frequency measurement on the first center frequency for the UE <NUM> which is a subset of the frequency set including the first center frequency, the second center frequency, the third center frequency and the fourth center frequency, and subcarrier spacing of measured SSB is also the same, the type of frequency measurement performed by the UE <NUM> is an intra-frequency measurement. When the second BS <NUM>-<NUM> configures a SSB-based frequency measurement on a fifth center frequency which is not a subset of the frequency set or with different SSB subcarrier spacing, the type of frequency measurement performed by the UE <NUM> is an inter-frequency measurement.

For another example, when the second BS <NUM>-<NUM> receives the CSI-RS frequency information (e.g., the first starting frequency, the first offset frequency and the first bandwidth) of the first serving cell and the SSB frequency information (e.g. the second center frequency and second subcarrier spacing) of the second serving cell of the first BS <NUM>-<NUM>, the frequency information of all the serving cells of the UE <NUM> from both the first BS <NUM>-<NUM> and the second BS <NUM>-<NUM> is available to the second BS <NUM>-<NUM>. When the second BS <NUM>-<NUM> configures a SSB-based frequency measurement on the third center frequency, the type of frequency measurement performed by the UE <NUM> is an inter-frequency measurement. When the second BS <NUM>-<NUM> configures a CSI-RS-based frequency measurement at the first starting frequency, first offset frequency with the first bandwidth, the type of frequency measurement performed by the UE <NUM> is an inter-frequency measurement.

In some embodiments, when the first message is received by the first BS <NUM>-<NUM>, the first BS <NUM>-<NUM> can also determine the type of frequency measurement by comparing the frequency information of all the serving cells from both the first BS <NUM>-<NUM> and the second BS <NUM>-<NUM> and the measurement frequency configured by the first BS <NUM>-<NUM> for the UE <NUM>.

The method <NUM> continues with operation <NUM> in which the first BS <NUM>-<NUM> transmits a second message to the second BS <NUM>-<NUM> according to some embodiments. In some embodiments, the second message is transmitted from the first BS <NUM>-<NUM> to the second BS <NUM>-<NUM> through a UE-specific inter-node RRC message. In some embodiments, the second message comprises a frequency measurement configuration. In some embodiments, the second message transmitted from the first BS <NUM>-<NUM> comprises at least one restriction of the frequency measurement configured by the second BS <NUM>-<NUM> for the UE <NUM>. In some embodiments, the at least one restriction transmitted from the first BS <NUM>-<NUM> to the second BS <NUM>-<NUM> comprises one of the following: a maximum number of allowed intra-frequency measurement identities and a maximum number of allowed inter-frequency measurement identities that can be configured by the second BS <NUM>-<NUM> to the UE <NUM>.

In some embodiments, the maximum number of allowed intra-frequency measurement identities comprises an integer, which can be used for configuring each serving frequencies of the respective serving cells. In some embodiments, the maximum number of allowed intra-frequency measurement identities comprises a plurality of integers for configuring a plurality of respective serving frequencies of respective serving cells. In some embodiments, the plurality of integers of the plurality of respective serving frequencies may be different. In some embodiments, the serving frequencies of the corresponding integers are also specified in the second message.

In some embodiments, when the maximum number of allowed intra-frequency measurement identities of a respective frequency in the second message from the first BS <NUM>-<NUM> is "<NUM>", the second BS <NUM>-<NUM> is not allowed to configure the maximum number of allowed intra-frequency measurement on the respective frequency for the UE <NUM>. In some embodiments, when a maximum number of allowed intra-frequency measurement identities of a respective frequency is not specified in the first message, the second BS <NUM>-<NUM> can configure a maximum number of intra-frequency measurement identities by itself which is not restricted by the first BS <NUM>-<NUM>. In some embodiments, the maximum number of allowed intra-frequency measurement identities configured by the second BS <NUM>-<NUM> is equal to or less than a predefined value. In some embodiments, the predefined value is preconfigured in the specifications or configured by the system.

For example, the first BS <NUM>-<NUM> is a master gNB (MgNB), which has a first serving cell operating on a first frequency, and a second serving cell operating on a second frequency. The second BS <NUM>-<NUM> is a secondary gNB (SgNB), which has a third serving cell operating on a third frequency and a fourth serving cell operating on a fourth frequency. During a secondary node addition or modification procedure, the first BS <NUM>-<NUM> transmits a second message to the second BS <NUM>-<NUM> through an inter-node RRC message (e.g., CG-ConfigInfo). In one embodiments, the first message comprises a maximum number (e.g., X=<NUM>) of allowed intra-frequency measurement identities for the serving frequencies including the first frequency, the second frequency, the third frequency and the fourth frequency. In some embodiments, the first message comprises a list of maximum numbers of allowed intra-frequency measurement identities X=[X1, X2, X3, X4]=[<NUM>, <NUM>, <NUM>, <NUM>], which corresponds to the first frequency, the second frequency, the third frequency and the fourth frequency. Specifically, the maximum number of allowed intra-frequency measurement identities that can be configured by BS <NUM>-<NUM> for the first NR frequency is <NUM>; the maximum number of allowed intra-frequency measurement identities that can be configured by BS <NUM>-<NUM> for the second NR frequency is <NUM>; the maximum number of allowed intra-frequency measurement identities that can be configured by BS <NUM>-<NUM> for the third NR frequency is <NUM>; and the maximum number of allowed intra-frequency measurement identities that can be configured by BS <NUM>-<NUM> for the fourth NR frequency is <NUM>. In some embodiments, the list of maximum number of allowed intra-frequency measurement identities X=[X1, X2, X4]=[<NUM>, <NUM>, <NUM>] corresponding to the first frequency, the second frequency and the fourth frequency. In some embodiments, the maximum number of allowed intra-frequency measurement identities that can be configured by BS <NUM>-<NUM> for the third frequency is not specified by the first BS <NUM>-<NUM> in the second message.

In some embodiments, the second message comprises a maximum number of allowed inter-frequency measurement identities that can be configured by BS <NUM>-<NUM>. In some embodiments, the maximum number of allowed inter-frequency measurement identities that can be configured by BS <NUM>-2comprises an integer for all the inter-frequencies. In some embodiments, if the integer in the second message is "<NUM>", the second BS <NUM>-<NUM> is not allowed to configure the maximum number of allowed inter-frequency measurement that can be configured by BS <NUM>-<NUM> for the UE <NUM>. In some embodiments, when an integer in the second message is not specified for a serving frequency, the second BS <NUM>-<NUM> can configure a maximum number of allowed inter-frequency measurement identities for the serving frequency by itself without restrictions from the first BS <NUM>-<NUM>. In some embodiments, the total maximum numbers of allowed inter-frequency measurement identities for at least one frequencies configured by the second BS <NUM>-<NUM> is equal to or less than a predefined value. In some embodiments, the predefined value is preconfigured in the specifications or configured by the system.

For example, the first BS <NUM>-<NUM> is a primary wireless communication node, which has a first serving cell operating on a first frequency, and a second serving cell operating on a second frequency. The second BS <NUM>-<NUM> is a secondary wireless communication node, which has a third serving cell operating on a third frequency and a fourth serving cell operating on a fourth frequency. During a secondary node addition or modification procedure, the first BS <NUM>-<NUM> transmits a second message to the second BS <NUM>-<NUM> through an inter-node RRC message (e.g., CG-ConfigInfo). The second message comprises a maximum number (e.g., Y=<NUM>) of allowed inter-frequency measurement identities for frequency other than the first frequency, the second frequency, the third frequency and the fourth frequency. When the second BS <NUM>-<NUM> configures a maximum number of allowed inter-frequency measurement identities for a fifth frequency and a sixth frequency, which are not a subset of the serving frequencies of serving cells, the summation of the maximum numbers of allowed inter-frequency measurement identities can be configured by BS <NUM>-<NUM> for the fifth frequency and the sixth frequency is equal to or less than Y=<NUM>.

The method <NUM> continues with operation <NUM> in which the second BS <NUM>-<NUM> determines a frequency measurement configuration according to some embodiments. In some embodiments, the type of a frequency measurement is determined after receiving the first message from the first BS <NUM>-<NUM>. In some embodiments, the configuration of the frequency measurement is determined by the second BS <NUM>-<NUM> according to the at least one restriction received in the second message from the first BS <NUM>-<NUM>. In some embodiments, the configuration of the frequency measurement comprises one of the following: a number of intra-frequency measurement identities or a number of inter-frequency measurement identities that can be configured by BS <NUM>-<NUM> according to some embodiments. In some embodiments, the number of intra-frequency measurement identities and the number of inter-frequency measurement identities each is equal to or less than the maximum number of allowed intra-frequency measurement identities and the maximum number of allowed inter-frequency measurement identities that can be configured by BS <NUM>-<NUM> received in the second message, respectively.

For example, when a maximum number (e.g., X=<NUM>) of allowed intra-frequency measurement identities that can be configured by BS <NUM>-<NUM> is transmitted to the second BS <NUM>-<NUM> from the first BS <NUM>-<NUM>, the second BS <NUM>-<NUM> further configures a number of frequency measurement identities for each serving frequency of the UE <NUM> according to the maximum number. Specifically, a first number of intra-frequency measurement identities for the first frequency is equal to or smaller than X; a second number of intra-frequency measurement identities for the second frequency is equal to or smaller than X; a third number of intra-frequency measurement identities for the third frequency is equal to or smaller than X; and a fourth number of intra-frequency measurement identities for the fourth frequency is equal to or smaller than X.

For another example, when a maximum number (X=[X1, X2, X3, X4]=[<NUM>, <NUM>, <NUM>, <NUM>]) of allowed intra-frequency measurement identities that can be configured by BS <NUM>-<NUM> for corresponding serving frequencies is transmitted to the second BS <NUM>-<NUM> from the first BS <NUM>-<NUM>, the second BS <NUM>-<NUM> configures frequency measurements for the UE <NUM>. Specifically, a first number of intra-frequency measurement identities for the first frequency is equal to or smaller than X1=<NUM>; a second number of intra-frequency measurement identities for the second frequency is equal to or smaller than X2=<NUM>; a third number of intra-frequency measurement identities for the third frequency is equal to or smaller than X3=<NUM>; and a fourth number of intra-frequency measurement identities for the fourth frequency is equal to or smaller than X4=<NUM>.

For another example, when a maximum number (e.g., X=[X1, X2, X4]=[<NUM>, <NUM>, <NUM>]) of allowed intra-frequency measurement identities that can be configured by BS <NUM>-<NUM> for the corresponding serving frequencies is transmitted to the second BS <NUM>-<NUM> from the first BS <NUM>-<NUM>, the second BS <NUM>-<NUM> configures frequency measurement for the UE <NUM>. Specifically, a first number of intra-frequency measurement identities for the first frequency is equal to or smaller than X1=<NUM>; and a fourth number of intra-frequency measurement identities for the fourth frequency is equal to or smaller than X4=<NUM>. Further, since X2=<NUM>, the second BS <NUM>-<NUM> is not allowed to configure a second number of intra-frequency measurement identities for the second frequency; and since X3 is not specified in the second message, the second BS <NUM>-<NUM> can configure a third number of intra-frequency measurement identities for the third frequency by itself without restrictions from the first BS <NUM>-<NUM>, which is equal to or less than a predefined number.

For another example, when a maximum number (e.g., Y=<NUM>) of allowed inter-frequency measurement identities is transmitted to the second BS <NUM>-<NUM> from the first BS <NUM>-<NUM>, the second BS <NUM>-<NUM> configures frequency measurement for the UE <NUM>. Specifically, a number of inter-frequency measurement identities for the each of all inter-frequencies is equal to or smaller than Y.

The method <NUM> continues with operation <NUM> in which the second BS <NUM>-<NUM> determines the type of frequency measurement according to some embodiments. In some embodiments, the second BS <NUM>-<NUM> determine the type of frequency measurement by comparing frequency information (e.g., a frequency set) of all serving cells and a measurement frequency. In some embodiments, when the measurement frequency on the UE is a subset of the frequency set of all the serving cells from both the first BS <NUM>-<NUM> and the second BS <NUM>-<NUM>, the type of frequency measurement is an intra-frequency measurement. In some other embodiments, when the measurement frequency is not a subset of the frequency set of all the serving cells, the type of frequency measurement is an inter-frequency measurement.

For example, when the second BS <NUM>-<NUM> receives the frequency information (e.g., the first center frequency and the second center frequency) from the first BS <NUM>-<NUM>, the frequency information of all the serving cells of the UE <NUM> is available to the second BS <NUM>-<NUM>. When the second BS <NUM>-<NUM> configures a SSB-based frequency measurement on the first center frequency for the UE <NUM> which is a subset of the frequency set including the first center frequency, the second center frequency, the third center frequency and the fourth center frequency, the type of frequency measurement performed by the UE <NUM> is an intra-frequency measurement. When the second BS <NUM>-<NUM> configures a SSB-based frequency measurement on a fifth center frequency which is not a subset of the frequency set, the type of frequency measurement performed by the UE <NUM> is an inter-frequency measurement.

For another example, when the second BS <NUM>-<NUM> receives the CSI-RS frequency information (e.g., the first starting frequency, the first offset frequency and the first bandwidth) of the first serving cell and the SSB frequency information (e.g., the second center frequency and second subcarrier spacing) of the second serving cell of the first BS <NUM>-<NUM>, the frequency information of all the serving cells of the UE <NUM> from both the first BS <NUM>-<NUM> and the second BS <NUM>-<NUM> is available to the second BS <NUM>-<NUM>. When the second BS <NUM>-<NUM> configures a SSB-based frequency measurement on the third center frequency, the type of frequency measurement performed by the UE <NUM> is an inter-frequency measurement. When the second BS <NUM>-<NUM> configures a CSI-RS-based frequency measurement at the first starting frequency, first offset frequency with the first bandwidth, the type of frequency measurement performed by the UE <NUM> is an inter-frequency measurement.

The method <NUM> continues with operation <NUM> in which the first BS <NUM>-<NUM> transmits a second message to the second BS <NUM>-<NUM> according to some embodiments. In some embodiments, the second message is transmitted from the first BS <NUM>-<NUM> to the second BS <NUM>-<NUM> through a UE-specific inter-node RRC message. In some embodiments, the second message comprises a frequency measurement configuration. In some embodiments, the second message transmitted from the first BS <NUM>-<NUM> comprises at least one restriction of the frequency measurement configured by the second BS <NUM>-<NUM> for the UE <NUM>. In some embodiments, the at least one restriction transmitted from the first BS <NUM>-<NUM> to the second BS <NUM>-<NUM> comprises one of the following: a first maximum number of allowed intra-frequency measurement identities and a first maximum number of allowed inter-frequency measurement identities that can be configured by the second BS <NUM>-<NUM> to the UE <NUM>.

In some embodiments, the first maximum number of allowed intra-frequency measurement identities comprises an integer, which can be used for configuring each serving frequencies of the respective serving cells. In some embodiments, the first maximum number of allowed intra-frequency measurement identities comprises a plurality of integers for configuring a plurality of respective serving frequencies of respective serving cells. In some embodiments, the plurality of integers of the plurality of respective serving frequencies may be different. In some embodiments, the serving frequencies of the corresponding integers are also specified in the second message.

In some embodiments, when the first maximum number of allowed intra-frequency measurement identities of a respective frequency in the second message from the first BS <NUM>-<NUM> is "<NUM>", the second BS <NUM>-<NUM> is not allowed to configure the first maximum number of allowed intra-frequency measurement on the respective frequency for the UE <NUM>. In some embodiments, when a first maximum number of allowed intra-frequency measurement identities of a respective frequency is not specified in the second message, the second BS <NUM>-<NUM> can configure a maximum number of intra-frequency measurement identities by itself which is not restricted by the first BS <NUM>-<NUM>. In some embodiments, the first maximum number of allowed intra-frequency measurement identities configured by the second BS <NUM>-<NUM> is equal to or less than a predefined value. In some embodiments, the predefined value is preconfigured in the specification or configured by the system.

For example, the first BS <NUM>-<NUM> is a master gNB (MgNB), which has a first serving cell operating on a first frequency, and a second serving cell operating on a second frequency. The second BS <NUM>-<NUM> is a secondary gNB (SgNB), which has a third serving cell operating on a third frequency and a fourth serving cell operating on a fourth frequency. During a secondary node addition or modification procedure, the first BS <NUM>-<NUM> transmits a second message to the second BS <NUM>-<NUM> through an inter-node RRC message (e.g., CG-ConfigInfo). In one embodiments, the second message comprises a first maximum number (e.g., X=<NUM>) of allowed intra-frequency measurement identities for the serving frequencies including the first frequency, the second frequency, the third frequency and the fourth frequency. In some embodiments, the second message comprises a list of maximum numbers of allowed intra-frequency measurement identities X=[X1, X2, X3, X4]=[<NUM>, <NUM>, <NUM>, <NUM>], which corresponds to the first frequency, the second frequency, the third frequency and the fourth frequency. Specifically, the maximum number of allowed intra-frequency measurement identities for the first frequency is <NUM>; the maximum number of allowed intra-frequency measurement identities for the second frequency is <NUM>; the maximum number of allowed intra-frequency measurement identities for the third frequency is <NUM>; and the maximum number of allowed intra-frequency measurement identities for the fourth frequency is <NUM>. In some embodiments, the first maximum numbers of allowed intra-frequency measurement identities (e.g., X=[X1, X2, X4]=[<NUM>, <NUM>, <NUM>]) and the corresponding frequencies (e.g., the first frequency, the second frequency and the fourth frequency) is transmitted in the second message. In some embodiments, the first maximum number of allowed intra-frequency measurement identities for the third frequency is not specified by the first BS <NUM>-<NUM> in the second message.

In some embodiments, the second message comprises a maximum number of allowed inter-frequency measurement identities. In some embodiments, the first maximum number of allowed inter-frequency measurement identities comprises an integer for all the inter-frequencies. In some embodiments, if the integer in the second message is "<NUM>", the second BS <NUM>-<NUM> is not allowed to configure the maximum number of allowed inter-frequency measurement for the UE <NUM>. In some embodiments, when an integer in the second message is not specified for a serving frequency, the second BS <NUM>-<NUM> can configure a maximum number of allowed inter-frequency measurement identities for the serving frequency by itself without restrictions from the first BS <NUM>-<NUM>. In some embodiments, the total maximum numbers of allowed inter-frequency measurement identities for at least one frequencies configured by the second BS <NUM>-<NUM> is equal to or less than a predefined value. In some embodiments, the predefined value is preconfigured in the specifications or configured by the system.

For example, the first BS <NUM>-<NUM> is a primary wireless communication node, which has a first serving cell operating on a first frequency, and a second serving cell operating on a second frequency. The second BS <NUM>-<NUM> is a secondary wireless communication node, which has a third serving cell operating on a third frequency and a fourth serving cell operating on a fourth frequency. During a secondary node addition or modification procedure, the first BS <NUM>-<NUM> transmits a second message to the second BS <NUM>-<NUM> through an inter-node RRC message (e.g., CG-ConfigInfo). The second message comprises a first maximum number (e.g., Y=<NUM>) of allowed inter-frequency measurement identities for frequency other than the first frequency, the second frequency, the third frequency and the fourth frequency. When the second BS <NUM>-<NUM> configures a number of inter-frequency measurement identities for a fifth frequency and a sixth frequency, which are not a subset of the serving frequencies of serving cells, the summation of the numbers of inter-frequency measurement identities for the fifth frequency and the sixth frequency is equal to or less than Y=<NUM>.

The method <NUM> continues with operation <NUM> in which the second BS <NUM>-<NUM> determines a first frequency measurement configuration according to some embodiments. In some embodiments, the type of a frequency measurement is determined after receiving the first message from the BS <NUM>. In some embodiments, the configuration of the frequency measurement is determined by the second BS <NUM>-<NUM> according to the at least one restriction received in the second message from the first BS <NUM>-<NUM>. In some embodiments, the configuration of the frequency measurement comprises one of the following: a number of intra-frequency measurement identities or a number of inter-frequency measurement identities according to some embodiments. In some embodiments, the number of intra-frequency measurement identities and the number of inter-frequency measurement identities each is equal to or less than the first maximum number of allowed intra-frequency measurement identities and the first maximum number of allowed inter-frequency measurement identities received in the second message, respectively.

For example, when a first maximum number (e.g., X=<NUM>) of allowed intra-frequency measurement identities is transmitted to the second BS <NUM>-<NUM> from the first BS <NUM>-<NUM>, the second BS <NUM>-<NUM> further configures a number of frequency measurement identities for each serving frequency of the UE <NUM> according to the first maximum number in the first configuration of the frequency measurement. Specifically, a first number of intra-frequency measurement identities for the first frequency is equal to or smaller than X; a second number of intra-frequency measurement identities for the second frequency is equal to or smaller than X; a third number of intra-frequency measurement identities for the third frequency is equal to or smaller than X; and a fourth number of intra-frequency measurement identities for the fourth frequency is equal to or smaller than X.

For another example, when a first maximum number (X=[X1, X2, X3, X4]=[<NUM>, <NUM>, <NUM>, <NUM>]) of allowed intra-frequency measurement identities for corresponding serving frequencies is transmitted to the second BS <NUM>-<NUM> from the first BS <NUM>-<NUM>, the second BS <NUM>-<NUM> configures frequency measurements for the UE <NUM>. Specifically, a first number of intra-frequency measurement identities for the first frequency is equal to or smaller than X1=<NUM>; a second number of intra-frequency measurement identities for the second frequency is equal to or smaller than X2=<NUM>; a third number of intra-frequency measurement identities for the third frequency is equal to or smaller than X3=<NUM>; and a fourth number of intra-frequency measurement identities for the fourth frequency is equal to or smaller than X4=<NUM>.

For another example, when a first maximum number (e.g., X=[X1, X2, X4]=[<NUM>, <NUM>, <NUM>]) of allowed intra-frequency measurement identities for the corresponding serving frequencies is transmitted to the second BS <NUM>-<NUM> from the first BS <NUM>-<NUM>, the second BS <NUM>-<NUM> configures frequency measurement for the UE <NUM>. Specifically, a first number of intra-frequency measurement identities for the first frequency is equal to or smaller than X1=<NUM>; and a fourth number of intra-frequency measurement identities for the fourth frequency is equal to or smaller than X4=<NUM>. Further, since X2=<NUM>, the second BS <NUM>-<NUM> is not allowed to configure a second number of intra-frequency measurement identities for the second frequency; and since X3 is not specified in the second message, the second BS <NUM>-<NUM> can configure a third number of intra-frequency measurement identities for the third frequency by itself without restrictions from the first BS <NUM>-<NUM>, which is equal to or less than a predefined value. In some embodiments, the predefined value is preconfigured in the specifications or configured by the system.

For another example, when a first maximum number (e.g., Y=<NUM>) of allowed inter-frequency measurement identities is transmitted to the second BS <NUM>-<NUM> from the first BS <NUM>-<NUM>, the second BS <NUM>-<NUM> configures frequency measurement for the UE <NUM>. Specifically, a number of inter-frequency measurement identities for the each of all the inter-frequencies is equal to or smaller than Y.

The method <NUM> continues with operation <NUM> in which the first BS <NUM>-<NUM> receives a third message from the second BS <NUM>-<NUM> according to some embodiments. In some embodiments, the third message comprises a configuration restriction request. In some embodiments, the configuration restriction request comprises one of the following: a second maximum number of allowed intra-frequency measurement identities and a second maximum number of allowed inter-frequency measurement identities that can be configured by the second BS <NUM>-<NUM> for the UE <NUM>. In some embodiments, the configuration restriction request in the second message also comprises information of respective frequencies. In some embodiments, the second maximum number is indicated explicitly in the third message. In some other embodiments, the third message comprises an extended number, wherein the extended number (a) is used to determine the second maximum number, e.g., the second maximum number equals a summation of the extended number (a) and the first maximum number, wherein a is a positive integer.

In some embodiments, the second maximum number of allowed intra-frequency measurement identities and the second maximum number of allowed inter-frequency measurement identities that can be configured by BS <NUM>-<NUM> are different from the first maximum number of allowed intra-frequency measurement identities and the first maximum number of allowed inter-frequency measurement identities that can be configured by BS <NUM>-<NUM> in the second message, respectively. In some embodiments, the second maximum number is different and greater than the first maximum number of allowed intra-frequency measurement identities and the first maximum number of allowed inter-frequency measurement identities, respectively, which is transmitted to the second BS <NUM>-<NUM> from the first BS <NUM>-<NUM> in the second message.

In some embodiments, the second maximum number of allowed intra-frequency measurement identities that can be configured by BS <NUM>-<NUM> comprises an integer for each of serving frequencies. In some embodiments, the second maximum number of allowed intra-frequency measurement identities that can be configured by BS <NUM>-<NUM> comprises a plurality of integers of a plurality of respective serving frequencies. In some embodiments, the plurality of integers of the plurality of respective serving frequencies may be different.

For example, when the second BS <NUM>-<NUM> is required to configure more numbers of intra-frequency measurements than the first maximum number X (e.g., X=<NUM>) of allowed intra-frequency measurement identities determined by the first BS <NUM>-<NUM>, the second BS <NUM>-<NUM> prepares and transmits a configuration restriction request with a second maximum number X' (e.g., X'=<NUM>) of allowed intra-frequency measurement entities to the first BS <NUM>-<NUM> through an inter-node RRC message (e.g., CG-Config).

For another example, when the second message comprises a list of first maximum numbers of allowed intra-frequency measurement identities (e.g., X=[X1, X2, X3]=[<NUM>, <NUM>, <NUM>]) that can be configured by BS <NUM>-<NUM> and when the second BS <NUM>-<NUM> is required to configure more numbers of intra-frequency measurements, the second BS <NUM>-<NUM> can also prepare and transmit a configuration restriction request with an extended number (a=<NUM>) and the respective frequency (e.g., the second frequency) to the first BS <NUM>-<NUM>. The extended number a is used to determine the second maximum number X' (e.g., Xi'=Xi+a, wherein i is the i-th frequency) of allowed intra-frequency measurement entities to the first BS <NUM>-<NUM>. The extended number a can be transmitted from the second BS <NUM>-<NUM> to the first BS <NUM>-<NUM> through an inter-node RRC message (e.g., CG-Config).

For another example, when the second BS <NUM>-<NUM> is required to configure more numbers of inter-frequency measurements than the first maximum number of allowed inter-frequency identities (e.g., Y=<NUM>) that can be configured by BS <NUM>-<NUM>, the second BS <NUM>-<NUM> prepares and transmits a configuration restriction request with a second maximum number Y' (e.g., Y'=<NUM>) of allowed inter-frequency measurement entities to the first BS <NUM>-<NUM> through an inter-node RRC message (e.g., CG-Config).

The method <NUM> continues with operation <NUM> in which the first BS <NUM>-<NUM> evaluates the configuration restriction request received from the second BS <NUM>-<NUM> and determine a second configuration of the frequency measurement according to some embodiments. In some embodiments, the second configuration of the frequency measurement comprises a third maximum number of one of the following: allowed intra-frequency measurement identities and allowed inter-frequency measurement identities that can be configured by BS <NUM>-<NUM>. In some embodiments, the third maximum number of allowed inter-frequency measurement identities and the third maximum number of allowed intra-frequency measurement identities that can be configured by BS <NUM>-<NUM> are determined according to available numbers of inter-frequency measurement identities and intra-frequency measurement identities. In some embodiments, the third maximum number can be the same as or different from the second maximum number received in the third message.

The method <NUM> continues with operation <NUM> in which the first BS <NUM>-<NUM> transmits a fourth message to the second BS <NUM>-<NUM> according to some embodiments. In some embodiments, the third message comprises one of the following: the third maximum number of allowed intra-frequency measurement identities and the third maximum number of allowed inter-frequency measurement identities determined by the first BS <NUM>-<NUM>. In some embodiments, the third maximum number can be the same as or different from the second maximum number received in the third message.

For example, the third maximum number of allowed intra-frequency measurement identities that can be configured by BS <NUM>-<NUM> equals the second maximum number (e.g., X'=<NUM>) of allowed intra-frequency measurement identities requested by the second BS <NUM>-<NUM> in the third message. The third maximum number, which is equal to the second maximum number (X') of allowed intra-frequency measurement identities, is then transmitted by the first BS <NUM>-<NUM> to the second BS <NUM>-<NUM>. The third maximum number of allowed intra-frequency measurement identities is then used for all the serving frequencies. The third maximum number of allowed intra-frequency measurement identities that can be configured by BS <NUM>-<NUM> can be less than the second maximum number (e.g., X'=<NUM>) of allowed intra-frequency measurement identities requested by the second BS <NUM>-<NUM>. For example, the third maximum number, which is equal to the first maximum number of allowed intra-frequency measurement identities (X=<NUM>) is then transmitted again by the first BS <NUM>-<NUM> to the second BS <NUM>-<NUM> through an inter-node RRC message (e.g., CG-ConfigInfo). The first maximum number of allowed intra-frequency measurement identities is then used for all the serving frequencies.

For another example, when an extended number (a=<NUM>) for the second frequency is received in the third message from the second BS <NUM>-<NUM>, the third maximum number of allowed intra-frequency measurement identities, which is equal to a summation of the first maximum number (X2=<NUM>) of allowed intra-frequency measurement identities of the respective frequency (e.g., second frequency) and the extended number (a), is then transmitted by the first BS <NUM>-<NUM> to the second BS <NUM>-<NUM> in the fourth message. The third maximum number of allowed intra-frequency measurement identities (e.g., X2+a=<NUM>) that can be configured by BS <NUM>-<NUM> is used for the second frequency. For another example, the third maximum number of allowed intra-frequency measurement identities that can be configured by BS <NUM>-<NUM>, which can be equal to the first maximum number of allowed intra-frequency measurement identities (X2=<NUM>) of the second frequency is then transmitted again by the first BS <NUM>-<NUM> back to the second BS <NUM>-<NUM>. The first maximum number of allowed intra-frequency measurement identities of X2=<NUM> is then used for the second frequency. For another example, the third maximum number of allowed intra-frequency measurement identities that can be configured by BS <NUM>-<NUM> can be also smaller than the first maximum number of allowed intra-frequency measurement identities, which can be transmitted back to the second BS <NUM>-<NUM> and used for the second frequency.

For another example, the third maximum number of allowed inter-frequency measurement identities that can be configured by BS <NUM>-<NUM>, can be equal to the second maximum number of allowed inter-frequency measurement identities Y', which is then transmitted by the first BS <NUM>-<NUM> to the second BS <NUM>-<NUM>. The third maximum number of allowed inter-frequency measurement identities that can be configured by BS <NUM>-<NUM> is then used for all the serving frequencies. On the other hand, the third maximum number of allowed inter-frequency measurement identities can be equal to or smaller than the first maximum number of allowed inter-frequency measurement identities (Y=<NUM>) is then transmitted again by the first BS <NUM>-<NUM> back to the second BS <NUM>-<NUM>. The third maximum number of allowed inter-frequency measurement identities that can be configured by BS <NUM>-<NUM> is then used for all the serving frequencies.

For another example, when an extended number (a=<NUM>) is received in the third message from the second BS <NUM>-<NUM>, the third maximum number of allowed inter-frequency measurement identities that can be configured by BS <NUM>-<NUM>, which is equal to a summation of the first maximum number (Y=<NUM>) of allowed inter-frequency measurement identities and the extended number (a), is then transmitted by the first BS <NUM>-<NUM> to the second BS <NUM>-<NUM>. The third maximum number of allowed inter-frequency measurement identities of the respective frequency (e.g., Y+a=<NUM>) is used for all the serving frequencies. On the other hand, the third maximum number of allowed inter-frequency measurement identities that can be configured by BS <NUM>-<NUM>, which can be equal to or smaller than the first maximum number of allowed inter-frequency measurement identities (Y=<NUM>) is then transmitted again by the first BS <NUM>-<NUM> back to the second BS <NUM>-<NUM>. The first maximum number of allowed inter-frequency measurement identities that can be configured by BS <NUM>-<NUM> is then used for all the serving frequencies.

<FIG> illustrates a method <NUM> for determining at least one reference timing for gap calculation, in accordance with some embodiments of the present disclosure. It is understood that additional operations may be provided before, during, and after the method <NUM> of <FIG>, and that some operations may be omitted or reordered. The communication system in the illustrated embodiment comprises a first BS <NUM>-<NUM>. In the illustrated embodiments, a UE <NUM> is in one of at least one serving cell covered by the first BS <NUM>-<NUM> and also in one of at least one serving cell covered by the second BS <NUM>-<NUM> (not shown), i.e., the UE <NUM> is in connection with the first BS <NUM>-<NUM> and the second BS <NUM>-<NUM>. In some embodiments, the first BS <NUM>-<NUM> is a primary wireless communication node. It should be noted that any numbers of BS <NUM> can be used.

The method <NUM> starts with operation <NUM> in which the first BS <NUM>-<NUM> transmits a first message to the UE <NUM> according to some embodiments. In some embodiments, the first message comprises information of a timing reference. In some embodiments, the timing reference is also transmitted from the first BS <NUM>-<NUM> to the second BS <NUM>-<NUM>. In some embodiments, the timing reference is an explicit indicator to indicate whether a serving cell of the first BS <NUM>-<NUM> or the second BS <NUM>-<NUM> is used for gap calculation. In some embodiments, the timing reference is an indicator with a value of TRUE when a serving cell on a specific frequency is in a MCG or a value of FALSE when a serving cell on a specific frequency is in a SCG. In some other embodiments, the timing reference is an indication comprising an index of one of the following: a primary cell of the first BS <NUM>-<NUM> (PCell), a primary cell of the second BS <NUM>-<NUM> (PSCell), and a serving cell. In some embodiments, the information of the timing reference is indicated with respect to at least one of the following gap patterns: a Per-UE gap pattern, a Per-FR FR1 gap pattern, and a Per-FR FR2 gap pattern. In some embodiments, when the first message is transmitted from the first BS <NUM>-<NUM> to the UE <NUM>, the first message is an RRCReconfiguration message. In some embodiments, when the timing reference is transmitted from the first BS <NUM>-<NUM> to the second BS <NUM>-<NUM>, the timing reference is carried in an inter-node RRC message.

The method <NUM> continues with operation <NUM> in which the UE <NUM> determines the gap position according to some embodiments. In some embodiments, when an index of a serving cell is received, the UE <NUM> can determine a synchronization timing of the serving cell according to the index. After the synchronization timing is obtained according to the index of the serving cell, the position of the gap in the time domain can be determined according to the synchronization timing and the gap pattern.

For example, the first BS <NUM>-<NUM> and the second BS <NUM>-<NUM> comprises serving cells operating on a FR2 frequency. When the UE <NUM> is configured to perform frequency measurement on the FR2 frequency, the first BS <NUM>-<NUM> configures a gap pattern of the FR2 frequency and determines whether to use a respective system frame number (SFN) and a subframe of a serving cell on the FR2 frequency of the first BS <NUM>-<NUM> or the second BS <NUM>-<NUM> for calculating a position of the FR2 gap. The first BS <NUM>-<NUM> transmits an RRCReconfiguration message to the UE <NUM>, wherein the RRCReconfiguration message comprises the pattern of the FR2 gap and an indicator of the timing reference (e.g., use SCG-FR2serving). When the indicator is set to "TRUE", the SFN and the subframe of one of the serving cells on the FR2 frequency of the second BS <NUM>-<NUM> is used to determine the position of the FR2 gap. When the indicator is set to "FAULSE", the SFN and the subframe of one of the serving cells on the FR2 frequency of the first BS <NUM>-<NUM> are used to determine the position of the FR2 gap. The first BS <NUM>-<NUM> also transmits the gap pattern of the FR2 frequency and the indicator of the timing reference to the second BS <NUM>-<NUM> through an inter-node RRC message (e.g., CG-ConfigInfo).

For another example, the first BS <NUM>-<NUM> and the second BS <NUM>-<NUM> comprises serving cells operating on a FR2 frequency. When the UE <NUM> is configured to perform frequency measurement on the FR2 frequency, the first BS <NUM>-<NUM> configures a gap pattern of the FR2 frequency and determines whether to use a respective SFN and a subframe of a PCell on the FR2 frequency of the first BS <NUM>-<NUM> or a PSCell of the second BS <NUM>-<NUM> for calculating a position of the FR2 gap in the time domain. The first BS <NUM>-<NUM> transmits an RRCReconfiguration message to the UE <NUM>, wherein the RRCReconfiguration message comprises the gap pattern of the FR2 frequency and an indicator of the timing reference. When the indicator is set to "PSCell", the SFN and the subframe of the PSCell are used to determine the gap position of the FR2 frequency. The first BS <NUM>-<NUM> also transmits the gap pattern of the FR2 frequency and the indicator of the timing reference to the second BS <NUM>-<NUM> through an inter-node RRC message (e.g., CG-ConfigInfo).

A person of ordinary skill in the art would further appreciate that any of the various illustrative logical blocks, modules, processors, means, circuits, methods and functions described in connection with the aspects disclosed herein can be implemented by electronic hardware (e.g., a digital implementation, an analog implementation, or a combination of the two, which can be designed using source coding or some other technique), various forms of program or design code incorporating instructions (which can be referred to herein, for convenience, as "software" or a "software module), or combinations of both. Whether such functionality is implemented as hardware, firmware or software, or a combination of these technique, depends upon the particular application and design constraints imposed on the overall system. Skilled artisans can implement the described functionality in various ways for each particular application.

Claim 1:
A method for configuring a gap, comprising:
transmitting, by a first base station (<NUM>-<NUM>), a first message to a user equipment (<NUM>) to configure the gap, the first message comprising first time reference information and the first time reference information indicating a cell including, a primary cell of the first base station (<NUM>-<NUM>), a primary cell of a second base station (<NUM>-<NUM>), or a serving cell; and
configuring, by using the first message, the user equipment (<NUM>) to use a system frame number and a subframe of the cell for gap calculation.