WO2021253182A1

WO2021253182A1 - Method and apparatus for neighbor cell measurement

Info

Publication number: WO2021253182A1
Application number: PCT/CN2020/096184
Authority: WO
Inventors: Jie Shi; Lianhai WU; Haiming Wang; Jing HAN; Ran YUE
Original assignee: Lenovo (Beijing) Limited
Priority date: 2020-06-15
Filing date: 2020-06-15
Publication date: 2021-12-23

Abstract

Embodiments of the present application relate to a method and an apparatus for neighbor cell measurement of a user equipment (UE). According to an embodiment of the present application, a method may include: determining whether a condition for triggering a neighbor cell measurement for at least one neighbor cell is fulfilled based on measurement configuration information; and in response to determining that the condition is fulfilled, triggering the neighbor cell measurement before initiating a RRC connection re-establishment procedure of a UE. Embodiments of the present application can facilitate the successful RRC connection re-establishment procedure.

Description

METHOD AND APPARATUS FOR NEIGHBOR CELL MEASUREMENT

TECHNICAL FIELD

Embodiments of the present application generally relate to wireless communication technology, especially to a method and an apparatus for neighbor cell measurement of a user equipment (UE) , e.g., a narrow band internet of things (NB-IoT) UE.

BACKGROUND

NB-IoT technology is an emerging IoT technology. The NB-IoT technology can reduce the complexity of the terminal and the core network, achieve lower power consumption and extend battery life of the terminal, and achieve deeper coverage through redundant transmission.

For a NB-IoT UE in a RRC_CONNECTED mode, it will apply a radio resource control (RRC) connection re-establishment procedure after a radio link failure (RLF) is detected. During the RRC connection re-establishment procedure, the NB-IoT UE may perform a neighbor cell measurement to find a suitable cell for transmitting the RRC connection re-establishment request. However, during the above procedure, the RRC connection re-establishment may fail because the neighbor cell measurement is not fast enough for a UE to find a suitable cell efficiently.

Therefore, the industry desires an improved technology for neighbor cell measurement, so as to trigger the neighbor cell measurement timely, thereby facilitating a successful RRC connection re-establishment procedure.

SUMMARY OF THE APPLICATION

Some embodiments of the present application at least provide a technical solution for neighbor cell measurement of a UE.

According to some embodiments of the present application, a method may include: determining whether a condition for triggering a neighbor cell measurement for at least one neighbor cell is fulfilled based on measurement configuration information; and in response to determining that the condition is fulfilled, triggering the neighbor cell measurement before initiating a RRC connection re-establishment procedure of a UE.

According to some other embodiments of the present application, a method may include: transmitting measurement configuration information to a UE, wherein the measurement configuration information is used for determining a condition for triggering a neighbor cell measurement for at least one neighbor cell before a RRC connection re-establishment procedure.

Some embodiments of the present application also provide an apparatus, include: at least one non-transitory computer-readable medium having computer executable instructions stored therein, at least one receiver; at least one transmitter; and at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiver and the at least one transmitter. The computer executable instructions are programmed to implement any method as stated above with the at least one receiver, the at least one transmitter and the at least one processor.

Embodiments of the present application provide a technical solution for neighbor cell measurement of a UE, e.g., a NB-IoT UE. Accordingly, embodiments of the present application can facilitate the successful RRC connection re-establishment procedure.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which advantages and features of the application can be obtained, a description of the application is rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. These drawings depict only example embodiments of the application and are not therefore to be considered limiting of its scope.

FIG. 1 is a schematic diagram illustrating an exemplary wireless communication system 100 according to some embodiments of the present application;

FIG. 2 illustrates an exemplary RRC connection re-establishment procedure after a RLF of a UE according to some embodiments of the present application;

FIG. 3 is a flow chart illustrating a method for neighbor cell measurement of a UE according to some embodiments of the present application;

FIG. 4 illustrates an exemplary coverage range associated with a CE level according to some embodiments of the present application;

FIG. 5 is a flow chart illustrating a method for neighbor cell measurement of a UE according to some other embodiments of the present application;

FIG. 6 illustrates a simplified block diagram of an apparatus 600 for neighbor cell measurement of a UE according to some embodiments of the present application; and

FIG. 7 illustrates a simplified block diagram of an apparatus 700 for neighbor cell measurement of a UE according to some other embodiments of the present application.

DETAILED DESCRIPTION

The detailed description of the appended drawings is intended as a description of preferred embodiments of the present application, and is not intended to represent the only form in which the present application may be practiced. It should be understood that the same or equivalent functions may be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the present application.

Reference will now be made in detail to some embodiments of the present application, examples of which are illustrated in the accompanying drawings.

FIG. 1 is a schematic diagram illustrating an exemplary wireless communication system 100 according to an embodiment of the present application.

As shown in FIG. 1, the wireless communication system 100 can include at least one base station (BS) 101 and at least one UE 103. Although a specific number of BSs 101 and UEs 103, e.g., only one BS 101 and two UEs 103 (e.g., the UE 103a and the UE 103b) are depicted in FIG. 1, one skilled in the art will recognize that any number of the BSs 101 and UEs 103 may be included in the wireless communication system 100.

The BS 101 may be distributed over a geographic region, and generally be a part of a radio access network that may include one or more controllers communicably coupled to one or more corresponding BSs. In some embodiments of the present application, each BS may also be referred to as an access point, an access terminal, a base, a macro cell, a Node-B, an evolved Node B (eNB) , a gNB, a Home Node-B, a relay node, a device, or described using other terminology used in the art.

The UE 103a may be a legacy UE (or regular UE) compatible with existing technology, or a normal NR UE. For example, the UE 103a may be computing devices, such as desktop computers, laptop computers, personal digital assistants (PDAs) , tablet computers, smart televisions (e.g., televisions connected to the Internet) , set-top boxes, game consoles, security systems (including security cameras) , vehicle on-board computers, network devices (e.g., routers, switches, and modems) , or the like. According to an embodiment of the present application, the UE 103a may be a portable wireless communication device, a smart phone, a cellular telephone, a flip phone, a device having a subscriber identity module, a personal computer, a selective call receiver, or any other device that is capable of sending and receiving communication signals on a wireless network. In some embodiments of the present application, the UE 103a may be a wearable device, such as a smart watch, a fitness band, an optical head-mounted display, or the like. Moreover, the UE 103a may be referred to as a subscriber unit, a mobile, a mobile station, a user, a terminal, a mobile terminal, a wireless terminal, a fixed terminal, a subscriber station, a user terminal, or a device, or described using other terminology used in the art.

The UE 103b may be a capability reduced UE, for example, a NB-IoT UE or a enhance machine type communication (eMTC) UE. The capability reduced UE may be an industrial wireless sensor, a video surveillance, a wearable device, or another device with the characteristics of the capability reduced UE. Compared with a legacy UE, the capability reduced may have a smaller bandwidth to enable several Kbps to several Mbps throughput; and achieve a lower power consumption to enable a longer UE battery life, cost reduction, flexible latency requirement, flexible UE processing time, and flexible UE processing capability, etc. In some embodiments of the present application, at least one UE 103 may be a NB-IoT UE.

FIG. 2 illustrates an exemplary RRC connection re-establishment procedure after a RLF of a UE according to some embodiments of the present application.

Referring to FIG. 2, for a UE 103b (e.g., a NB-IoT UE) in a RRC_CONNECTED mode, it may perform normal operation with a serving cell (e.g., a cell of the BS 101) . At a certain time instance, the UE 103b may detect a radio link problem of a serving cell (e.g., a cell of BS 101) . For example, the UE 103b may detect an "out-of-sync" indication from a lower layer (e.g., a physical layer) . In the case that the UE 103b receives a first number (e.g., N310 as specified in 3GPP standard documents) of consecutive "out-of-sync" indications from the lower layer at a time T1, the UE 103b may start a first timer (e.g., T310 as specified in 3GPP standard documents) associated with a RLF. In the case that a second number (for example, N311 as specified in 3GPP standard documents) of consecutive "in-sync" indications are received from the lower layer, the UE 103b may stop the first timer. Otherwise, when the first timer expires, the UE 103b may declare a RLF.

In response to the RLF of the UE 103b, the UE 103b may initiate a cell selection procedure and start a second timer (for example, T311 as specified in 3GPP standard documents) associated with the cell selection procedure. During the cell selection procedure, the UE 103b may perform neighbor cell measurement to select a suitable cell for transmitting a RRC connection re-establishment request to that cell. In the case that a suitable cell is selected before the second timer expires, the UE 103b may stop the second timer, start a third timer (for example, T301 as specified in 3GPP standard documents) , and transmit a RRC connection re-establishment request to the suitable cell. Transmitting the RRC connection re-establishment request means triggering or initiating a RRC connection re-establishment procedure. Before the third timer expires, in the case that the RRC connection re-establishment procedure succeeds, the UE 103b may keep in the RRC_CONNECTED mode with the new cell, otherwise the UE 103b may go back to a RRC_IDLE mode.

During the above procedure, before transmitting the RRC connection re-establishment request to the suitable cell, the UE 103b may perform intra-frequency cell measurement for the serving cell. However, the neighbor cell measurement may only be performed after declaring a RLF of the UE 103b. The problem of the above procedure is that the neighbour cell measurement will be initiated after declaring a RLF of the UE 103b, which may lead to the failure of the RRC connection re-establishment procedure because neighbour cell measurement is not fast enough. After the neighbour cell measurement is completed, the UE may have already gone through several cells.

In order to find the neighbour cell efficiently and reduce the time taken to a RRC connection reestablishment procedure, embodiments of the present application provide solutions for neighbor cell measurement. Accordingly, embodiments of the present application can define the condition regarding when to perform the neighbor cell measurement so as to reduce the latency of the RRC connection reestablishment procedure, thereby facilitating a successful RRC connection re-establishment procedure and ensuring the service continuity. For example, embodiments of the present application can initiate a neighbor cell measurement before declaring a RLF of a UE or before initiating a RRC connection reestablishment procedure. More details on embodiments of the present application will be illustrated in the following text in combination with the appended drawings.

FIG. 3 is a flow chart illustrating a method for neighbor cell measurement of a UE according to some embodiments of the present application. The method may be performed by a UE 103b as shown in FIG. 1, for example, a NB-IoT UE.

As shown in FIG. 3, in step 302, the UE 103b may determine whether a condition for triggering a neighbor cell measurement for at least one neighbor cell is fulfilled based on measurement configuration information. The neighbor cell measurement may include at least one of an intra frequency neighbor cell measurement, an inter frequency neighbor cell measurement, and an intra frequency neighbor cell measurement and an inter frequency neighbor cell measurement. Then, in step 304, in response to determining that the condition is fulfilled, the UE 103b may trigger the neighbor cell measurement before initiating a RRC connection re-establishment procedure of a UE or before cell selection procedure during T311 timer is running.

The measurement configuration information may be configured by a base station (BS) or preconfigured in the UE. For example, the measurement configuration information may be transmitted to the UE 103b via a RRC signaling or through broadcast information.

In order to achieve a coverage enhancement, NR defines multiple CE levels, each CE level may correspond to a different measured RSRP value, measured RSRQ value, or other measured signal value. The base station (BS) and a NB-IoT terminal may select the corresponding number of information retransmissions according to the CE Level where they are located. In an embodiment of the present application, the CE levels may include CE level 0, CE level 1, and CE level 2, each of which may correspond to a measurement result lower than -144dB, -154dB, -164dB, respectively.

For example, FIG. 4 illustrates an exemplary coverage range associated with a CE level according to some embodiments of the present application.

Referring to FIG. 4, the BS 101 may have three coverage ranges, each coverage range may correspond to a CE level. As shown in FIG. 4, CE level 0 may correspond to the minimum coverage range 1, CE level 1 may correspond to the medium coverage range 2, and CE level 2 may correspond to the larger coverage range 3. According to some embodiments of the present application, the CE levels may also include a CE level 3 that corresponds to the maximum coverage range. The coverage enhancement may be achieved by increasing the maximum number of retransmissions. Persons skilled in the art can understand that three coverage ranges and three CE levels shown in FIG. 4 are only for illustrative purposes only. According to some other embodiments of the present application, the BS 101 may have any number of coverage ranges, where each coverage range may correspond to a different CE level. In an embodiment of the present application, the larger the CE level is, the larger the corresponding coverage range would be.

According to some embodiments of the present application, the measurement configuration information may indicate at least one of: a first set of threshold values associated with an intra frequency neighbor cell measurement, each threshold value in the first set of threshold values associated with a coverage enhancement (CE) level; a second set of threshold values associated with an inter frequency neighbor cell measurement, each threshold value in the second set of threshold values associated with the CE level; and a third set of threshold values associated with an intra frequency neighbor cell measurement and an inter frequency neighbor cell measurement, each threshold value in the third set of threshold values associated with the CE level.

In these embodiments, in order to determine whether the condition for triggering a neighbor cell measurement is fulfilled, the UE 103b may also determine a first signal measurement value of a serving cell of the UE 103b. According to some embodiments of the present application, in the case that the UE in a dual-connectivity mode, the serving cell may refer to a primary cell (PCell) or a primary secondary (PSCell) of the UE 103b. According to some embodiments of the present application, the serving cell may refer to a primary cell. In addition, the UE 103b may also determine a first CE level of a coverage range in which the UE is located. The first CE level of a coverage range may be determined based on the first signal measurement value of the serving cell. For example, assuming that the first signal measurement value of the UE is -157dB, a CE level 2 has a measurement result smaller than -154dB, and a CE level 3 has a measurement result smaller than -164dB, , then the UE 103 may determine that the first CE level of a coverage range in which the UE is located is 2.

In an embodiment of the present application, the first signal measurement value may be based on one of the followings: a reference signal receiving power (RSRP) value, a reference signal receiving quality (RSRQ) value, and a signal to interference plus noise ratio (SINR) value. Persons skilled in the art can understand that RSRP value, RSRQ value, and SINR value are not only for illustrative purposes. According to some other embodiments of the present application, the first signal measurement value may be other signal measurement values.

In an embodiment of the present application, the first signal measurement value is determined based on at least one parameter of the following parameters: Ms, Hys, and offset. The offset may be at least one of: a frequency specific offset, a cell specific offset, an event specific offset, and a CE level specific offset. The offset may be the combination of frequency specific offset and CE level specific offset, or the combination of frequency specific offset and event specific offset, or the combination of frequency specific offset, CE level specific offset, and event specific offset. The offset may be the combination of cell specific offset and CE level specific offset, or the combination of cell specific offset and event specific offset, or the combination of cell specific offset, CE level specific offset, and event specific offset. For example, the first signal measurement value may be determined based on one of the followings:

· Ms, wherein the Ms is a RSRP value or a RSRQ value of a serving cell of the UE 103b;

· Ms+Hys, wherein the Ms is a RSRP value or a RSRQ value of a serving cell of the UE 103b, and Hys is a hysteresis parameter as specified in 3GPP standard document;

· Ms+Hys+offset_CEn, wherein the Ms is a RSRP value or a RSRQ value of a serving cell of the UE 103b, Hys is a hysteresis parameter as specified in 3GPP standard document, and the offset_CEn is a CE level specific offset associated with a CE level n. For example, for the serving cell with four CE levels, the offset_CEn may have four values, each value may be associated with a CE level. Assuming that the first CE level of a coverage range in which the UE 103b is located is 2, then the offset_CEn used for determining the first signal measurement value should be offset_CE ₂ associated with the CE level 2;

· Ms+Ofs+Ocs+Hys+off, wherein the Ms is a RSRP value or a RSRQ value of a serving cell of the UE 103b, Hys is a hysteresis parameter as specified in 3GPP standard document, Ofs is a frequency specific offset as specified in 3GPP standard document, Ocs is a cell specific offset as specified in 3GPP standard document, and off is an event specific offset for a measurement event (for example, event to trigger neighbor cell measurement for NB-IOT UE in connected mode, or A3 event as specified in 3GPP standard document) as specified in 3GPP standard document;

· Ms+Ofs+Ocs+Hys, wherein the Ms is a RSRP value or a RSRQ value of a serving cell of the UE 103b, Hys is a hysteresis parameter as specified in 3GPP standard document, Ofs is a frequency specific offset as specified in 3GPP standard document, Ocs is a cell specific offset as specified in 3GPP standard document;

· Ms+Ofs+Ocs+Hys+offset_CEn, wherein the Ms is a RSRP value or a RSRQ value of a serving cell of the UE 103b, Hys is a hysteresis parameter as specified in 3GPP standard document, Ofs is a frequency specific offset as specified in 3GPP standard document, Ocs is a cell specific offset as specified in 3GPP standard document, the offset_CEn is a CE level specific offset associated with a CE level n;

· Ms+Ofs+Ocs+Hys+off+offset_CEn, wherein the offset_CEn is a CE level specific offset associated with a CE level n;

· Ms+Hys+offset, wherein in the offset may be any combination as stated above.

In another embodiment of the present application, the first signal measurement value may be determined based on the formula used for selecting a new cell in a cell re-selection or cell selection procedure as specified in 3GPP standard documents. For example, the formulation is related to the S criterion. For example, the first signal measurement value may be determined based on Q _rxlevmeas– (Q _rxlevmin+Q _{rxlevminoffset}) –Pcompensation -Qoffset _tem, wherein the Q _rxlevmeas is a RSRP value of a target cell measured by the UE, the Q _rxlevmin is a minimum receiving power level value, Q _{rxlevminoffset} is an offset value of the minimum receiving power level, Pcompensation is a power compensation value, and Qoffset _temp is an addition offset value. In another example, the first signal measurement value may be determined based on Q _qualmeas – (Q _qualmin + Q _{qualminoffset}) -Qoffset _temp, wherein the Q _qualmeas is a RSRQ value of a target cell measured by the UE, the Q _qualmin is a minimum quality level value, Q _{qualminoffset} is an offset value of the minimum quality level.

After determining the first signal measurement value of the serving cell of the UE 103b, the UE 103b may determine the condition for triggering the neighbor cell measurement based on the first signal measurement value and the measurement configuration information. In an embodiment of the present application, the condition for triggering the neighbor cell measurement may be one of: a first condition that the first signal measurement value is less than or equal to a threshold value associated with the first CE level of the coverage range in the first set of threshold values; a second condition that the first signal measurement value is less than or equal to a threshold value associated with the first CE level of the coverage range in the second set of threshold values; and a third condition that the first signal measurement value is less than or equal to a threshold value associated with the first CE level of the coverage range in the third set of threshold values.

The corresponding neighbor cell measurement may be triggered in the case that the corresponding condition is fulfilled. In an embodiment of the present application, in the case that the first condition is fulfilled, the UE 103b may trigger the intra frequency neighbor cell measurement; in the case that the second condition is fulfilled, the UE 103b may trigger the inter frequency neighbor cell measurement; and in the case that the third condition is fulfilled, the UE 103b may triggering the intra frequency neighbor cell measurement and the inter frequency neighbor cell measurement.

For example, assuming that the first signal measurement value is S, the first set of threshold values include thresholdA_CE ₀ associated with CE level 0, thresholdA_CE ₁ associated with CE level 1, thresholdA_CE ₂ associated with CE level 2, the second set of threshold values may include thresholdB_CE ₀ associated with CE level 0, thresholdB_CE ₁ associated with CE level 1, thresholdB_CE ₂ associated with CE level 2, the third set of threshold values may include thresholdC_CE ₀ associated with CE level 0, thresholdC_CE ₁ associated with CE level 1, thresholdC_CE ₂ associated with CE level 2. Moreover, assuming that the first CE level of the coverage range is CE level 2, then the UE 103b may compare the value S with thresholdA_CE ₂, thresholdB_CE ₂, thresholdC_CE _2. In the case that S <thresholdA_CE ₂ or S ≤ thresholdA_CE ₂, the UE 103b may trigger the intra frequency neighbor cell measurement. In the case that S < thresholdB_CE ₂ or S ≤thresholdB_CE ₂, the UE 103b may trigger the inter frequency neighbor cell measurement. In the case that S < thresholdC_CE ₂ or S ≤ thresholdC_CE ₂, the UE 103b may trigger the intra frequency neighbor cell measurement and the intra frequency neighbor cell measurement.

In other words, the UE 103b may compare the value S with thresholdA_CE ₂, thresholdB_CE ₂, thresholdC_CE _2. In the case that S ≥ thresholdA_CE ₂ or S >thresholdA_CE ₂, the UE 103b may not trigger the intra frequency neighbor cell measurement. In the case that S ≥ thresholdB_CE ₂ or S > thresholdB_CE ₂, the UE 103b may not trigger the inter frequency neighbor cell measurement. In the case that S ≥ thresholdC_CE ₂ or S > thresholdC_CE ₂, the UE 103b may not trigger the intra frequency neighbor cell measurement and the intra frequency neighbor cell measurement.

According to some other embodiments of the present application, the measurement configuration information may indicate a fourth set of threshold values. Each threshold value in the fourth set of threshold values associated with at least one of an intra frequency neighbor cell measurement, an inter frequency neighbor cell measurement, or an intra frequency neighbor cell measurement and an inter frequency neighbor cell measurement.

In these embodiments, in order to determine whether the condition for triggering a neighbor cell measurement is fulfilled, the UE 103b may also determine a second signal measurement value of a serving cell of the UE 103b. In an embodiment of the present application, the second signal measurement value may be based on one of the followings: a RSRP value, a RSRQ value, or a SINR value. In the case that the second signal measurement value is less than or equal to a threshold value in the fourth set of threshold values, the UE 103b may trigger a corresponding neighbor cell measurement associated with the threshold value.

In an embodiment of the present application, the second signal measurement the first signal measurement value may be determined based on at least one parameter of the following parameters: Ms, Hys, and offset. The offset may be at least one of: a frequency specific offset, a cell specific offset, an event specific offset, and a CE level specific offset. The offset may be the combination of frequency specific offset and CE level specific offset, or the combination of frequency specific offset and event specific offset, or the combination of frequency specific offset, CE level specific offset, and event specific offset. The offset may be the combination of cell specific offset and CE level specific offset, or the combination of cell specific offset and event specific offset, or the combination of cell specific offset, CE level specific offset, and event specific offset. For example, the first signal measurement value may be determined based on one of the followings:

· Ms+Hys+offset_CEn, wherein the Ms is a RSRP value or a RSRQ value of a serving cell of the UE 103b, Hys is a hysteresis parameter as specified in 3GPP standard document, and the offset_CEn is a CE level specific offset associated with a CE level n. For example, for the serving cell with three CE levels, the offset_CEn may have three values, each value may be associated with a CE level. Assuming that the CE level of a coverage range in which the UE 103b is located is 2, then the offset_CEn used for determining the second signal measurement should be offset_CE ₂ associated with the CE level 2;

· Ms+Ofs+Ocs+Hys+off, wherein the Ms is a RSRP value or a RSRQ value of a serving cell of the UE 103b, Hys is a hysteresis parameter as specified in 3GPP standard document, Ofs is a frequency specific offset as specified in 3GPP standard document, Ocs is a cell specific offset as specified in 3GPP standard document, and off is an event specific offset for a measurement event as specified in 3GPP standard document;

· Ms+Hys+offset, where in the Ms is a RSRP value or a RSRQ value of a serving cell of the UE 103b, Hys is a hysteresis parameter as specified in 3GPP standard document, offset may be any combination as stated above.

For example, assuming that the second signal measurement value is S, and the fourth set of threshold values includes thresholdA associated with the intra frequency neighbor cell measurement, thresholdB associated with the intra frequency neighbor cell measurement, and thresholdC associated with the intra frequency neighbor cell measurement and the inter frequency neighbor cell measurement. The UE 103b may compare the value S with thresholdA, thresholdB, and thresholdC _. In the case that S< thresholdA or S ≤ thresholdA, the UE 103b may trigger the intra frequency neighbor cell measurement. In the case that S< thresholdA or S≤thresholdB, the UE 103b may trigger the inter frequency neighbor cell measurement. In the case that S< thresholdA or S≤ thresholdC, the UE 103b may trigger the intra frequency neighbor cell measurement and the inter frequency neighbor cell measurement.

In other words, the UE 103b may compare the value S with thresholdA, thresholdB, and thresholdC. In the case that S ≥ thresholdA or S > thresholdA, the UE 103b may not trigger the intra frequency neighbor cell measurement. In the case that S ≥ thresholdB or S > thresholdB, the UE 103b may not trigger the inter frequency neighbor cell measurement. In the case that S ≥ thresholdC or S >thresholdC, the UE 103b may not trigger the intra frequency neighbor cell measurement and the intrer frequency neighbor cell measurement.

According to some embodiment of the present application, the measurement configuration information may indicate at least one of: a fifth set of threshold values and a sixth set of threshold values associated with an intra frequency neighbor cell measurement, each threshold value in the fifth set and sixth set of threshold values associated with a CE level; a seventh set of threshold values and a eighth set of threshold values associated with an inter frequency neighbor cell measurement, each threshold value in the seventh set and eighth set of threshold values associated with the CE level; and an ninth set of threshold values and a tenth set of threshold values associated with an intra frequency neighbor cell measurement and an inter frequency neighbor cell measurement, each threshold value in the eighth set and ninth set of threshold values associated with the CE level.

In these embodiments, in order to determine whether the condition for triggering a neighbor cell measurement is fulfilled, the UE 103b may also determine a third signal measurement value and a fourth signal measurement value of a serving cell of the UE 103b. The UE 103b may also determine a second CE level of a coverage range in which the UE is located. In an embodiment of the present application, the third signal measurement value may be based on a RSRP value and the fourth signal measurement value may be based on a RSRQ value.

In an embodiment of the present application, the third signal measurement value or the fourth signal measurement value may be determined based on at least one parameter of the following parameters: Ms, Hys, and offset. The offset may be at least one of: a frequency specific offset, a cell specific offset, an event specific offset, and a CE level specific offset. The offset may be the combination of frequency specific offset and CE level specific offset, or the combination of frequency specific offset and event specific offset, or the combination of frequency specific offset, CE level specific offset, and event specific offset. The offset may be the combination of cell specific offset and CE level specific offset, or the combination of cell specific offset and event specific offset, or the combination of cell specific offset, CE level specific offset, and event specific offset. For example, the third signal measurement value or the fourth signal measurement value may be determined based on one of the followings:

· Ms+Hys+offset_CEn, wherein the Ms is a RSRP value or a RSRQ value of a serving cell of the UE 103b, Hys is a hysteresis parameter as specified in 3GPP standard document, and the offset_CEn is a CE level specific offset associated with a CE level n. For example, for the serving cell with three CE levels, the offset_CEn may have three values, each value may be associated with a CE level. Assuming that the second CE level of a coverage range in which the UE 103b is located is 2, then the offset_CEn should be offset_CE ₂ associated with the CE level 2;

· Ms+Ofs+Ocs+Hys+off+offset_CEn, wherein the offset_CEn is a CE level specific offset associated with a CE level n as defined above; and

In another embodiment of the present application, the third signal measurement value and the fourth signal measurement value may be determined based on the formula used for selecting a new cell in a cell re-selection or cell selection procedure as specified in 3GPP standard documents. For example, the formula is related to the S criterion. For example, the third signal measurement value may be determined based on Q _rxlevmeas – (Q _rxlevmin + Q _{rxlevminoffset}) –Pcompensation -Qoffset _tem, wherein the Q _rxlevmeas is a RSRP value of a target cell measured by the UE, the Q _rxlevmin is a minimum receiving power level value, Q _{rxlevminoffset} is an offset value of the minimum receiving power level, Pcompensation is a power compensation value, and Qoffset _temp is an addition offset value. The fourth signal measurement value may be determined based on Q _qualmeas – (Q _qualmin + Q _{qualminoffset}) -Qoffset _temp, wherein the Q _qualmeas is a RSRQ value of a target cell measured by the UE, the Q _qualmin is a minimum quality level value, Q _{qualminoffset} is an offset value of the minimum quality level.

After determining the third signal measurement value and the fourth signal measurement value of the serving cell of the UE 103b, the UE 103b may determine the condition for triggering the neighbor cell measurement based on the third and fourth signal measurement values and the measurement configuration information. In an embodiment of the present application, the condition for triggering the neighbor cell measurement may be one of: a fourth condition that the third signal measurement value is less than or equal to a threshold value associated with the second CE level in the fifth set of threshold values and that the fourth signal measurement value is less than or equal to a threshold value associated with the second CE level in the sixth set of threshold values; a fifth condition that the third signal measurement value is less than or equal to a threshold value associated with the second CE level in the seventh set of threshold values and that the fourth signal measurement value is less than or equal to a threshold value associated with the second CE level in the eighth set of threshold values; and a sixth condition that the third signal measurement value is less than or equal to a threshold value associated with the second CE level in the ninth set of threshold values and that the fourth signal measurement value is less than or equal to a threshold value associated with the second CE level in the tenth set of threshold values.

The corresponding neighbor cell measurement may be triggered in the case that the corresponding condition is fulfilled. In an embodiment of the present application, in the case that the fourth condition is fulfilled, the UE 103b may trigger the intra frequency neighbor cell measurement; in the case that the fifth condition is fulfilled, the UE 103b may trigger the inter frequency neighbor cell measurement; and in the case that the sixth condition is fulfilled, the UE 103b may trigger the intra frequency neighbor cell measurement and the inter frequency neighbor cell measurement.

For example, assuming that the first signal measurement value is S and the second signal measurement value is S', the fifth set of threshold values may include thresholdA_CE ₀ associated with CE level 0, thresholdA_CE ₁ associated with CE level 1, thresholdA_CE ₂ associated with CE level 2; the sixth set of threshold values may include thresholdA'_CE ₀ associated with CE level 0, thresholdA'_CE ₁ associated with CE level 1, thresholdA'_CE ₂ associated with CE level 2; the seventh set of threshold values may include thresholdB_CE ₀ associated with CE level 0, thresholdB_CE ₁ associated with CE level 1, thresholdB_CE ₂ associated with CE level 2; the eighth set of threshold values may include thresholdB'_CE ₀ associated with CE level 0, thresholdB'_CE ₁ associated with CE level 1, thresholdB'_CE ₂ associated with CE level 2; the ninth set of threshold values may include thresholdC_CE ₀ associated with CE level 0, thresholdC_CE ₁ associated with CE level 1, thresholdC_CE ₂ associated with CE level 2; the tenth set of threshold values may include threshold'_CE ₀ associated with CE level 0, thresholdC'_CE ₁ associated with CE level 1, thresholdC'_CE ₂ associated with CE level 2.

Moreover, assuming that the second CE level of the coverage range is CE level 2, then the UE 103b may compare the value S with thresholdA_CE ₂, thresholdB_CE ₂, thresholdC_CE ₂ and compare the value S' with thresholdA'_CE ₂, thresholdB'_CE ₂, thresholdC'_CE _2. In the case that S < thresholdA_CE ₂ or S ≤thresholdA_CE ₂ and S'< thresholdA'_CE ₂ or S'≤ thresholdA'_CE ₂, the UE 103b may trigger the intra frequency neighbor cell measurement. In the case that S <thresholdB_CE ₂ or S ≤ thresholdB_CE ₂ and S' < thresholdB'_CE ₂ or S' ≤thresholdB'_CE ₂, the UE 103b may trigger the inter frequency neighbor cell measurement. In the case that S < thresholdC_CE ₂ or S ≤ thresholdC_CE ₂ and S' <thresholdC'_CE ₂ or S' ≤ thresholdC'_CE ₂, the UE 103b may trigger the intra frequency neighbor cell measurement and the intra frequency neighbor cell measurement.

In other words, in the case that S ≥ thresholdA_CE ₂ or S > thresholdA_CE ₂ and S' ≥ thresholdA'_CE ₂ or S' > thresholdA'_CE ₂, the UE 103b may not trigger the intra frequency neighbor cell measurement. In the case that S ≥ thresholdB_CE ₂ or S > thresholdB_CE ₂ and S' ≥ thresholdB'_CE ₂ or S' > thresholdB'_CE ₂, the UE 103b may not trigger the inter frequency neighbor cell measurement. In the case that S ≥thresholdC_CE ₂ or S > thresholdC_CE ₂ and S' ≥ thresholdC'_CE ₂ or S' >thresholdC'_CE ₂, the UE 103b may not trigger the intra frequency neighbor cell measurement and the intra frequency neighbor cell measurement.

According to some other embodiments of the present application, the measurement configuration information indicates at least one pair of threshold values, wherein each pair of at least one pair of threshold values is associated with an intra frequency neighbor cell measurement, an inter frequency neighbor cell measurement, or an intra frequency neighbor cell measurement and an inter frequency neighbor cell measurement. In an embodiment of the present application, one threshold value in a pair of threshold values is a RSRP threshold value and the other threshold value in the pair of threshold values is a RSRQ threshold value

In these embodiments, in order to determine whether the condition for triggering a neighbor cell measurement is fulfilled, the UE 103b may also determine a fifth signal measurement value and sixth signal measurement value of a serving cell of the UE 103b. In an embodiment of the present application, the fifth signal measurement value is based on a RSRP value and the sixth signal measurement value is based on a RSRQ value. In the case that the fifth signal measurement value is less than or equal to one threshold value in a pair of threshold values and the sixth signal measurement value is less than or equal to another threshold value in the pair of threshold values, trigger a corresponding neighbor cell measurement associated with the pair of threshold values.

In some other embodiments, in the case that the fifth signal measurement value is larger than one threshold value in a pair of threshold values or the sixth signal measurement value is larger than another threshold value in the pair of threshold values, the UE 103b may not trigger a corresponding neighbor cell measurement associated with the pair of threshold values.

In some other embodiments, in the case that the fifth signal measurement value is larger than one threshold value in a pair of threshold values and the sixth signal measurement value is larger than another threshold value in the pair of threshold values, the UE 103b may not trigger a corresponding neighbor cell measurement associated with the pair of threshold values.

In an embodiment of the present application, the fifth signal measurement value or the sixth signal measurement value may be determined based on at least one parameter of the following parameters: Ms, Hys, and offset. The offset may be at least one of: a frequency specific offset, a cell specific offset, an event specific offset, and a CE level specific offset. The offset may be the combination of frequency specific offset and CE level specific offset, or the combination of frequency specific offset and event specific offset, or the combination of frequency specific offset, CE level specific offset, and event specific offset. The offset may be the combination of cell specific offset and CE level specific offset, or the combination of cell specific offset and event specific offset, or the combination of cell specific offset, CE level specific offset, and event specific offset. For example, the fifth signal measurement value or the sixth signal measurement value may be determined based on one of the followings:

· Ms+Hys+offset_CEn, wherein the Ms is a RSRP value or a RSRQ value of a serving cell of the UE 103b, Hys is a hysteresis parameter as specified in 3GPP standard document, and the offset_CEn is a CE level specific offset associated with a CE level n. For example, for the serving cell with three CE levels, the offset_CEn may have three values, each value may be associated with a CE level. Assuming that the CE level of a coverage range in which the UE 103b is located is 2, then the offset_CEn should be offset_CE ₂ associated with the CE level 2;

· Ms+Ofs+Ocs+Hys+off+offset_CEn, wherein the offset_CEn is a CE level specific offset associated with a CE level n; and

For example, assuming that the fifth signal measurement value is S and the sixth signal measurement value is S', the measurement configuration information indicates thresholdA and thresholdA' associated with the intra frequency neighbor cell measurement, thresholdB and thresholdB' associated with the intrer frequency neighbor cell measurement, and threshold and thresholdC' associated with the intra frequency neighbor cell measurement and the inter frequency neighbor cell measurement. The UE 103b may compare the value S with thresholdA, thresholdB, and thresholdC and compare the value S' with thresholdA', thresholdB', and threshold C'. In the case that S < thresholdA or S ≤ thresholdA and S' < thresholdA' or S' ≤thresholdA', the UE 103b may trigger the intra frequency neighbor cell measurement. In the case that S < thresholdB or S ≤ thresholdB and S' < thresholdB' or S' ≤thresholdB', the UE 103b may trigger the inter frequency neighbor cell measurement. In the case that S < thresholdC or S ≤ thresholdC and S' < thresholdC' or S' ≤thresholdC', the UE 103b may trigger the intra frequency neighbor cell measurement and the intra frequency neighbor cell measurement.

In other words, the UE 103b may compare the value S with thresholdA, thresholdB, and thresholdC and compare the value S' with thresholdA', thresholdB', and threshold C'. In the case that S ≥ thresholdA or S > thresholdA and S' ≥thresholdA' or S' > thresholdA', the UE 103b may not trigger the intra frequency neighbor cell measurement. In the case that S ≥ thresholdB or S > thresholdB and S' ≥ thresholdB' or S' > thresholdB', the UE 103b may not trigger the inter frequency neighbor cell measurement. In the case that S ≥ thresholdC or S > thresholdC and S' ≥ thresholdC' or S' > thresholdC', the UE 103b may not trigger the intra frequency neighbor cell measurement and the intra frequency neighbor cell measurement..

According to some embodiments of the present application, the measurement configuration information may indicate CE level information for triggering the neighbor cell measurement. The UE 103b may trigger the neighbor cell measurement in the case that the UE 103b is located in a coverage range having the CE level information indicated in the measurement configuration information. In an embodiment of the present application, the CE level information may be used in combination with the above threshold values and conditions for triggering the neighbor cell measurement. That is, in the case that the UE 103b is located in a coverage range having the CE level information indicated in the measurement configuration information, the UE 103b may use the above condition to trigger the neighbor cell measurement. The CE level information may be a CE value, a RSRP value, or a RSRQ value.

In an embodiment of the present application, the CE level information is indicated to the UE via a dedicated signaling or broadcast information. For example, the dedicated signaling or broadcast information may explicitly indicate a value of the CE level. In another example, the dedicated signaling or broadcast information may indicate a RSRP value and/or a RSRQ value such that the UE 103b may determine the CE level based on the RSRP value and/or the RSRQ value. For example, the dedicated signaling or broadcast information may include a specific value, the specific value is used to indicate the CE level information where UE performs the neighbor cell measurement.

In another embodiment of the present application, the CE level information may be preconfigured in the UE 103b. In this embodiment, the UE 103b may indicate the CE level information to the serving cell such that the serving cell can know that the neighbor cell measurement is performed in which CE level. For example, the UE 103b may explicitly indicate a value of the CE level to the serving cell. In another example, the UE 103b may indicate a RSRP value and/or a RSRQ value such that the serving cell may determine the CE level based on the RSRP value and/or a RSRQ value.

According to some embodiments of the present application, the measurement configuration information may indicate that triggering a neighbor cell measurement is based on a CE level changing of the UE. For example, the measurement configuration information may indicate that triggering a neighbor cell measurement is based on a CE level changing from CE level 0 to CE level 1 or from CE level 1 to CE level 2 as shown in FIG. 4. Then the UE 103b may determine whether the condition of CE level changing is fulfilled, in the case that the CE level changing is fulfilled, the UE 103b may trigger the neighbor cell measurement.

In some cases, the condition on when UE performs the corresponding neighbour cell measurement before RLF may be determined based on radio link monitoring procedure.

According to some embodiments of the present application, the measurement configuration information may indicate a first number of consecutive "out-of-sync" indications. The first the first number of consecutive "out-of-sync" indications may be N310 as specified in 3GPP standard documents or may be any other numbers.

In an embodiment of the present application, the UE 103b may determine that the condition for triggering a neighbor cell measurement is that the first number of consecutive "out-of-sync" indications for a serving cell is detected by the UE. In the case the condition is fulfilled, the UE 103b may trigger the neighbor cell measurement.

In an embodiment of the present application, the UE 103b may determine that the condition is that the first number of consecutive "out-of-sync" indications for a serving cell is detected by the UE 103b when a first timer associated with a radio link failure (RLF) is running. In an embodiment of the present application, the first timer may be T310 as specified in 3GPP standard documents. In the case the condition is fulfilled, the UE may trigger the neighbor cell measurement.

According to some embodiments of the present application, the measurement configuration information may indicate a second number of consecutive "out-of-sync" indications; and configuration information for a second timer. The second number of consecutive "out-of-sync" indications may be N310 as specified in 3GPP standard documents or may be any other numbers. The configuration information for the second timer may indicate a length of the second timer.

In these embodiment, after receiving the second number of consecutive "out-of-sync" indications for a serving cell when a first timer (e.g., T310 as specified in 3GPP standard documents) associated with a RLF is running, the UE 103b may start the second timer. The UE may trigger the neighbor cell measurement in the case that the second timer expires.

In an embodiment of the present application, the measurement configuration information may indicate a third number of consecutive "in-sync" indications. The third number of consecutive "in-sync" indications may be N311 as specified in 3GPP standard documents or may be any other numbers. The UE 103b may stop the second timer in the case that third number of consecutive "in-sync" indications for the serving cell is detected by the UE 103b or the first timer is stopped

According to some embodiments of the present application, the measurement configuration information may indicate configuration information for a third timer. The configuration information for the third timer may indicate a length of the third timer.

In these embodiment, the UE 103b may start the third timer when a first timer (e.g., T310 as specified in 3GPP standard documents) associated with a RLF is started. The UE may trigger the neighbor cell measurement in the case that the third timer expires.

In an embodiment of the present application, the measurement configuration information may indicate a fourth number of consecutive "in-sync" indications. The fourth number of consecutive "in-sync" indications may be N311 as specified in 3GPP standard documents or may be any other numbers. The UE 103b may stop the third timer in the case that fourth number of consecutive "in-sync" indications for the serving cell is detected by the UE 103b or the first timer is stopped.

According to some embodiments of the present application, the measurement configuration information may indicate a first time length. The UE 103b may trigger the neighbor cell measurement at a time point when a time that a first timer (e.g., T310 as specified in 3GPP standard documents) associated with a RLF is predicted to be expired minus the first time length. For example, assuming that a time that a first timer associated with a RLF is predicted to be expired is 500ms, and the first time length is 200ms, the UE 103b may trigger the neighbor cell measurement at 300ms (i.e., 500ms -300ms) after the first timer is started.

According to some embodiments of the present application, the measurement configuration information may configuration information for a fourth timer. The configuration information for the fourth timer may indicate a length of the fourth timer.

In these embodiment, the UE 103b may start the fourth timer at a time point when a time that a first timer (e.g., T310 as specified in 3GPP standard documents) associated with a RLF is predicted to be expired minus the time length of fourth timer The UE may trigger the neighbor cell measurement in the case that the fourth timer is started. For example, assuming that a time that a first timer associated with a RLF is predicted to be expired is 500ms, and the length of the fourth timer is 200ms, the UE 103b may start the fourth timer and trigger the neighbor cell measurement at 300ms (i.e., 500ms -300ms) after the first timer is started.

In an embodiment of the present application, the measurement configuration information may indicate a fifth number of consecutive "in-sync" indications. The fourth number of consecutive "in-of-sync" indications may be N311 as specified in 3GPP standard documents or may be any other numbers. The UE 103b may stop the fourth timer in the case that fifth number of consecutive "in-sync" indications for the serving cell is detected by the UE 103b or the first timer is stopped.

The "in-sync" indication and the "out-of-sync" indication may be determined based on a SINR value of the serving cell and a SINR threshold value. According to some embodiments of the present application, the measurement configuration information may indicate at least one SINR threshold value. Each SINR threshold value is associated with a CE level. For example, for the serving cell with three

CE levels

0, 1, and 2 as shown in FIG. 4, the measurement configuration information may indicate three SINR threshold values associated with

CE levels

0, 1, and 2, respectively. Assuming that the CE level of a coverage range in which the UE 103b is located is 2, then the UE 103b may use the SINR threshold value associated with CE level 2 to determine "in-sync" indication and the "out-of-sync" indication.

According to some embodiments of the present application, the measurement configuration information may indicate a sixth number of retransmissions. In these embodiments, the condition is that the sixth number of retransmissions occur in a radio link control (RLC) layer of the UE 103b. In the case the condition is fulfilled, the UE may trigger the neighbor cell measurement.

According to some embodiments of the present application, the corresponding neighbor cell measurement may be triggered in the case that the combination of more than one corresponding conditions are fulfilled. The measurement configuration information may be the combination of the measurement configuration information of each corresponding condition. For example, the UE 103b may compare the value S with thresholdA, thresholdB, and thresholdC _. In the case that S < thresholdA or S ≤ thresholdA and the second timer is expired, the UE 103b may trigger the intra frequency neighbor cell measurement.

According to some embodiments of the present application, the configuration information may indicate CE level information applied in a radio link management (RLM) procedure or the RLF procedure. The CE level information may be a value of a CE level, a RSRP value, a RSRQ value, or a SINR value applied in "out-of-sync" and or "in-sync" in PDCCH detecting in RLM procedure or RLF procedure. UE may trigger the neighbor cell measurement only in the RLM procedure or RLF procedure with the indicated CE level information. UE may trigger the neighbor cell measurement only in the RRC connection re-establishment procedure where UE camped in a cell range with the indicated CE level information. The CE level information may indicate one or more types of information. For example, the CE level information may include one or more values of the CE level, the RSRP value, and the RSRQ value, or one or more SINR values.

According to some embodiments of the present application, the configuration information may indicate CE level information applied in neighbor cell measurement. UE will measure the neighbor cell associated with the indicated CE level information. The CE level information may be a value of CE level, or a RSRP value or a RSRQ value associated with a CE level. The CE level information may indicate one or more types of information. For example, the CE level information may include one or more values of CE level, RSRP value or RSRQ value.

According to some embodiments of the present application, the UE 103b may stop the neighbor cell measurement in response to one or more of the followings: a signal quality of a new cell measured by the UE is higher than or equal to a threshold; one period or multiple periods for neighbor cell measurement are finished; and a signal quality of a serving cell of the UE is higher than or equal than to a threshold. The UE 103b may stop the neighbor cell measurement in response to one or more of the followings: the fourth timer is stopped, or a number of consecutive "in-sync" indications are received. In an embodiment of the present application, one period for neighbor cell measurement being finished may refer to the neighbor cell measurement for all of the at least one neighbor cell configured by the serving cell are performed once. In another embodiment of the present application, the signal quality may be one of the followings: a RSRP value, a RSRQ value, and a SINR value. In yet another embodiment of the present application, the thresholds used in the above embodiments may be configured by a serving cell of the UE 103b or may be preconfigured in the UE 103b.

In some cases, the target cell needs to retrieve the UE context from source cell after receiving the RRC connection re-establishment request from the UE. In order to reduce the latency and ensure service continuity, some assistant information can be transmitted to the source cell such that the source cell may prepare the UE context and transmit the UE context to the candidate cell (s) which may receive the RRC connection re-establishment request in the future.

According to some embodiments of the present application, the UE 103b may transmit an assistant message to a serving cell of the UE 103b. The assistance information may implicitly or explicitly indicate at least one of the followings: the UE 103b will trigger the RRC connection re-establishment procedure; CE level of a target cell to which a RRC connection re-establishment will be transmitted; cell global identifier (CGI) of the target cell; CE level of a serving cell; a measurement value of the serving cell; CE level of a neighbor cell; a measurement value of the neighbor cell; CGI of the neighbor cell. Here, the UE will trigger the RRC connection re-establishment procedure means that UE will potentially trigger the the RRC connection re-establishment procedure. The RRC connection re-establishment message may not be transmitted if the serving cell channel quality is improved.

In an embodiment of the present application, the assistance information may explicitly indicate the above item. For example, the assistance information may explicitly include the value of the above item. In another embodiment of the present application, the assistance information may implicitly indicate the above item. For example, the assistance information may include an indication indicating the value of the above item.

In an embodiment of the present application, the target cell may be one of the at least one neighbor cell for which the UE 103b performs neighbor cell measurement and the serving cell of the UE 103b.

In an embodiment of the present application, the measurement value may include one of the followings: a RSRP value, a RSRQ value, and a SINR value.

In an embodiment of the present application, the assistance information may indicate CE levels of one or more neighbor cells, measurement values of one or more neighbor cells; and/or CGI information of the one or more neighbor cells.

In an embodiment of the present application, the CGI of a cell may include E-UTRAN CGI (ECGI) of the cell, or PCI of the cell.

In an embodiment of the present application, the assistant message is transmitted via a RRC signaling or via a media access control (MAC) control element (CE) . In an embodiment of the present application, a new logical identity (LGID) may be allocated to the MAC CE for transmitting the assistant message. The MAC CE may have a higher priority than other MAC service data unit (SDU) or MAC CE including buffer status report (BSR) .

In an embodiment of the present application, the assistant message may be transmitted by a preconfigured uplink resource or by a Msg. A in a two-step random access channel (RACH) procedure as specified in 3GPP standard documents.

In an embodiment of the present application, the UE 103b may transmit the assistant message in response to one or more of the followings: the neighbor cell measurement is finished; a seventh number of "out-of-sync" indications is detected by the UE; and a signal quality of a serving cell of the UE is below a threshold. In an embodiment of the present application, the signal quality of a serving cell may be at least one of the followings: a RSRP value, a RSRQ value, and a SINR value. In another embodiment of the present application, the seventh number of "out-of-sync" indications or the threshold may be configured by the serving cell of the UE 103b or preconfigured in the UE 103b.

FIG. 5 is a flow chart illustrating a method for neighbor cell measurement of a UE according to some other embodiments of the present application. The method may be performed by a BS 101 as shown in FIG. 1.

As shown in FIG. 5, in step 502, the BS 101 may transmit measurement configuration information to a UE 103b (for example, a NB-IoT UE) as shown in FIG. 1. The measurement configuration information may be used for determining a condition for triggering a neighbor cell measurement for at least one neighbor cell before a RRC connection re-establishment procedure of the UE 103b. The neighbor cell measurement may include at least one of an intra frequency neighbor cell measurement, an inter frequency neighbor cell measurement, and an intra frequency neighbor cell measurement and an inter frequency neighbor cell measurement.

The measurement configuration information may be transmitted to the UE 103b via a RRC signaling or through broadcast information.

For example, assuming that the BS 101 have three CE levels as shown in FIG. 4, the first set of threshold values may include thresholdA_CE ₀ associated with CE level 0, thresholdA_CE ₁ associated with CE level 1, thresholdA_CE ₂ associated with CE level 2, the second set of threshold values may include thresholdB_CE ₀ associated with CE level 0, thresholdB_CE ₁ associated with CE level 1, thresholdB_CE ₂ associated with CE level 2, the third set of threshold values may include thresholdC_CE ₀ associated with CE level 0, thresholdC_CE ₁ associated with CE level 1, thresholdC_CE ₂ associated with CE level 2.

In these embodiments, the condition for triggering the neighbor cell measurement may be one of: a first condition that the first signal measurement value is less than or equal to a threshold value associated with the first CE level of the coverage range in the first set of threshold values; a second condition that the first signal measurement value is less than or equal to a threshold value associated with the first CE level of the coverage range in the second set of threshold values; and a third condition that the first signal measurement value is less than or equal to a threshold value associated with the first CE level of the coverage range in the third set of threshold values.

In an embodiment of the present application, the first signal measurement value may be based on one of the followings: a RSRP value of a serving cell of the UE 103b, a RSRQ value of a serving cell of the UE 103b, and a SINR value of a serving cell of the UE 103b. According to some embodiments of the present application, in the case that the UE in a dual-connectivity mode, the serving cell may refer to a PCell or a PSCell of the UE 103b.

For example, the fourth set of threshold values includes thresholdA associated with the intra frequency neighbor cell measurement, thresholdB associated with the intra frequency neighbor cell measurement, and thresholdC associated with the intra frequency neighbor cell measurement and the inter frequency neighbor cell measurement.

In these embodiments, the condition may be that a second signal measurement value is less than or equal to a threshold value in the fourth set of threshold values. In an embodiment of the present application, the second signal measurement value may be based on one of the followings: a RSRP value of a serving cell of the UE 103b, a RSRQ value of a serving cell of the UE 103b, or a SINR value of a serving cell of the UE 103b.

For example, assuming that the BS 101 has three CE levels as shown in FIG. 4, the fifth set of threshold values may include thresholdA_CE ₀ associated with CE level 0, thresholdA_CE ₁ associated with CE level 1, thresholdA_CE ₂ associated with CE level 2; the sixth set of threshold values may include thresholdA'_CE ₀ associated with CE level 0, thresholdA'_CE ₁ associated with CE level 1, thresholdA'_CE ₂ associated with CE level 2; the seventh set of threshold values may include thresholdB_CE ₀ associated with CE level 0, thresholdB_CE ₁ associated with CE level 1, thresholdB_CE ₂ associated with CE level 2; the eighth set of threshold values may include thresholdB'_CE ₀ associated with CE level 0, thresholdB'_CE ₁ associated with CE level 1, thresholdB'_CE ₂ associated with CE level 2; the ninth set of threshold values may include thresholdC_CE ₀ associated with CE level 0, thresholdC_CE ₁ associated with CE level 1, thresholdC_CE ₂ associated with CE level 2; the tenth set of threshold values may include threshold'_CE ₀ associated with CE level 0, thresholdC'_CE ₁ associated with CE level 1, thresholdC'_CE ₂ associated with CE level 2.

In these embodiments, the condition may be one of: a fourth condition that a third signal measurement value is less than or equal to a threshold value associated with a second CE level of a coverage range in which the UE is located in the fifth set of threshold values and that the fourth signal measurement value is less than or equal to a threshold value associated with the second CE level in the sixth set of threshold values; a fifth condition that the third signal measurement value is less than or equal to a threshold value associated with the second CE level of a coverage range in which the UE is located in the seventh set of threshold values and that the fourth signal measurement value is less than or equal to a threshold value associated with the second CE level in the eighth set of threshold values; and a sixth condition that the third signal measurement value is less than or equal to a threshold value associated with the second CE level of a coverage range in which the UE is located in the ninth set of threshold values and that the fourth signal measurement value is less than or equal to a threshold value associated with the second CE level in the tenth set of threshold values.

In an embodiment of the present application, the third signal measurement value may be based on a RSRP value and the fourth signal measurement value may be based on a RSRQ value.

For example, the measurement configuration information indicates thresholdA and thresholdA' associated with the intra frequency neighbor cell measurement, thresholdB and thresholdB' associated with the intra frequency neighbor cell measurement, and threshold and thresholdC' associated with the intra frequency neighbor cell measurement and the inter frequency neighbor cell measurement.

In these embodiments, the condition may be that a fifth signal measurement value is less than or equal to one threshold value in a pair of threshold values and the sixth signal measurement value is less than or equal to another threshold value in the pair of threshold values. In an embodiment of the present application, the fifth signal measurement value is based on a RSRP value of a serving cell of the UE 103b and the sixth signal measurement value is based on a RSRQ value of a serving cell of the UE 103b.

According to some embodiments of the present application, the measurement configuration information may indicate CE level information for triggering the neighbor cell measurement.

In an embodiment of the present application, the CE level information is indicated to the UE via a dedicated signaling or broadcast information for the UE. For example, the dedicated signaling or broadcast information may explicitly indicate a value of the CE level information. In another example, the dedicated signaling or broadcast information may indicates a RSRP value and/or a RSRQ value such that the UE 103b may determine the CE level information based on the RSRP value and/or a RSRQ value. For example, the dedicated signaling or broadcast information may include a specific value, the specific value is used to indicate the CE level information where UE performs the neighbor cell measurement.

According to some embodiments of the present application, the measurement configuration information may indicate that triggering a neighbor cell measurement is based on a CE level changing of the UE. For example, the measurement configuration information may indicate that triggering a neighbor cell measurement is based on a CE level changing from CE level 0 to CE level 1 or from CE level 1 to CE level 2 as shown in FIG. 4.

In an embodiment of the present application, the condition for triggering a neighbor cell measurement is that the first number of consecutive "out-of-sync" indications for a serving cell is detected by the UE.

In another embodiment of the present application, the condition for triggering a neighbor cell measurement is that the first number of consecutive "out-of-sync" indications for a serving cell is detected by the UE 103b when a first timer associated with a radio link failure (RLF) is running. In an embodiment of the present application, the first timer may be T310 as specified in 3GPP standard documents.

According to some embodiments of the present application, the measurement configuration information may indicate a second number of consecutive "out-of-sync" indications; and configuration information for a second timer. The second number of consecutive "out-of-sync" indications may be N310 as specified in 3GPP standard documents or may be any other numbers. The configuration information for the second timer may indicate a length of the second timer. In these embodiments, the condition may be that the second timer expires.

In an embodiment of the present application, the measurement configuration information may indicate a third number of consecutive "in-sync" indications. The third number of consecutive "in-sync" indications may be N311 as specified in 3GPP standard documents or may be any other numbers.

According to some embodiments of the present application, the measurement configuration information may indicate configuration information for a third timer. The configuration information for the third timer may indicate a length of the third timer. In these embodiments, the condition may be that the third timer expires.

In an embodiment of the present application, the measurement configuration information may indicate a fourth number of consecutive "in-sync" indications. The fourth number of consecutive "in-sync" indications may be N311 as specified in 3GPP standard documents or may be any other numbers.

According to some embodiments of the present application, the measurement configuration information may indicate a first time length. In these embodiments, the condition may be is a time point when a time that a first timer associated with a RLF is predicted to be expired minus the first time length.

According to some embodiments of the present application, the measurement configuration information may indicate configuration information for a fourth timer. The configuration information for the fourth timer may indicate a length of the fourth timer. In these embodiments, the condition may be that the fourth timer is started.

In an embodiment of the present application, the measurement configuration information may indicate a fifth number of consecutive "in-sync" indications. The fourth number of consecutive "in-of-sync" indications may be N311 as specified in 3GPP standard documents or may be any other numbers.

According to some embodiments of the present application, the measurement configuration information may indicate at least one SINR threshold value for the UE103b to determine "in-sync" indication and the "out-of-sync" indication. Each SINR threshold value is associated with a CE level. For example, for the serving cell with three

CE levels

0, 1, and 2, respectively.

According to some embodiments of the present application, the measurement configuration information may indicate a sixth number of retransmissions. In these embodiments, the condition is that the sixth number of retransmissions occur in a RLC layer of the UE 103b.

According to some embodiments of the present application, at step 504, the BS 101 may receive an assistant message. Step 504 is an optional step and can be performed independently from the step 502. The assistance information may implicitly or explicitly indicate at least one of the followings: the UE will trigger the RRC connection re-establishment procedure; CE level of a target cell to which a RRC connection re-establishment will be transmitted; CGI of the target cell; CE level of a serving cell; a measurement value of the serving cell; CE level of a neighbor cell; a measurement value of the neighbor cell; CGI of the neighbor cell.

In an embodiment of the present application, the assistance information may explicitly indicate the above item. For example, the assistance information may include the value of the above item. In another embodiment of the present application, the assistance information may implicitly indicate the above item. For example, the assistance information may include an indication indicating the value of the above item.

In an embodiment of the present application, the CGI of a cell may include ECGI of the cell.

In an embodiment of the present application, the assistant message is received via a RRC signaling or via a media access control (MAC) control element (CE) . In an embodiment of the present application, a new logical identity (LGID) may be allocated to the MAC CE for transmitting the assistant message, the MAC CE may have a higher priority than other MAC service data unit (SDU) or MAC CE including buffer status report (BSR) .

In an embodiment of the present application, the assistant message may be received by a preconfigured uplink resource or by a Msg. A in a two-step random access channel (RACH) procedure as specified in 3GPP standard documents.

According to some embodiments of the present application, the consecutive "in-sync" indications could be replaced by accumulative "in-sync" . The consecutive "out-sync" indications could be replaced by accumulative "out-sync" .

FIG. 6 illustrates a simplified block diagram of an apparatus 600 for neighbor cell measurement of a UE according to some embodiments of the present application. The apparatus 600 may be a UE 103b as shown in FIG. 1.

Referring to FIG. 6, the apparatus 600 may include at least one non-transitory computer-readable medium 602, at least one receiving circuitry 604, at least one transmitting circuitry 606, and at least one processor 608. In some embodiment of the present application, at least one receiving circuitry 604 and at least one transmitting circuitry 606 and be integrated into at least one transceiver. The at least one non-transitory computer-readable medium 602 may have computer executable instructions stored therein. The at least one processor 608 may be coupled to the at least one non-transitory computer-readable medium 602, the at least one receiving circuitry 604 and the at least one transmitting circuitry 606. The computer executable instructions can be programmed to implement a method with the at least one receiving circuitry 604, the at least one transmitting circuitry 606 and the at least one processor 608 The method can be a method according to an embodiment of the present application, for example, the method shown in FIG. 4.

FIG. 7 illustrates a simplified block diagram of an apparatus 700 for neighbor cell measurement of a UE according to some other embodiments of the present application. The apparatus 700 may be a BS 101 as shown in FIG. 1.

Referring to FIG. 7, the apparatus 700 may include at least one non-transitory computer-readable medium 702, at least one receiving circuitry 704, at least one transmitting circuitry 706, and at least one processor 708. In some embodiment of the present application, at least one receiving circuitry 704 and at least one transmitting circuitry 706 and be integrated into at least one transceiver. The at least one non-transitory computer-readable medium 702 may have computer executable instructions stored therein. The at least one processor 708 may be coupled to the at least one non-transitory computer-readable medium 702, the at least one receiving circuitry 704 and the at least one transmitting circuitry 706. The computer executable instructions can be programmed to implement a method with the at least one receiving circuitry 704, the at least one transmitting circuitry 706 and the at least one processor 708.

The method according to embodiments of the present application can also be implemented on a programmed processor. However, the controllers, flowcharts, and modules may also be implemented on a general purpose or special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit elements, an integrated circuit, a hardware electronic or logic circuit such as a discrete element circuit, a programmable logic device, or the like. In general, any device on which resides a finite state machine capable of implementing the flowcharts shown in the figures may be used to implement the processor functions of this application. For example, an embodiment of the present application provides an apparatus for emotion recognition from speech, including a processor and a memory. Computer programmable instructions for implementing a method for emotion recognition from speech are stored in the memory, and the processor is configured to perform the computer programmable instructions to implement the method for emotion recognition from speech. The method may be a method as stated above or other method according to an embodiment of the present application.

An alternative embodiment preferably implements the methods according to embodiments of the present application in a non-transitory, computer-readable storage medium storing computer programmable instructions. The instructions are preferably executed by computer-executable components preferably integrated with a network security system. The non-transitory, computer-readable storage medium may be stored on any suitable computer readable media such as RAMs, ROMs, flash memory, EEPROMs, optical storage devices (CD or DVD) , hard drives, floppy drives, or any suitable device. The computer-executable component is preferably a processor but the instructions may alternatively or additionally be executed by any suitable dedicated hardware device. For example, an embodiment of the present application provides a non-transitory, computer-readable storage medium having computer programmable instructions stored therein. The computer programmable instructions are configured to implement a method for emotion recognition from speech as stated above or other method according to an embodiment of the present application.

While this application has been described with specific embodiments thereof, it is evident that many alternatives, modifications, and variations may be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added, or substituted in the other embodiments. Also, all of the elements of each figure are not necessary for operation of the disclosed embodiments. For example, one of ordinary skill in the art of the disclosed embodiments would be enabled to make and use the teachings of the application by simply employing the elements of the independent claims. Accordingly, embodiments of the application as set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the application.

Claims

A method, comprising:

determining whether a condition for triggering a neighbor cell measurement for at least one neighbor cell is fulfilled based on measurement configuration information; and

in response to determining that the condition is fulfilled, triggering the neighbor cell measurement before initiating a radio resource control (RRC) connection re-establishment procedure of a user equipment (UE) .
The method of claim 1, wherein the measurement configuration information indicates at least one of:

a first set of threshold values associated with an intra frequency neighbor cell measurement, each threshold value in the first set of threshold values associated with a coverage enhancement (CE) level;

a second set of threshold values associated with an inter frequency neighbor cell measurement, each threshold value in the second set of threshold values associated with the CE level; and

a third set of threshold values associated with an intra frequency neighbor cell measurement and an inter frequency neighbor cell measurement, each threshold value in the third set of threshold values associated with the CE level.
The method of Claim 2, further comprising:

determining a first CE level of a coverage range in which the UE is located; and

determining a first signal measurement value of a serving cell of the UE.
The method of Claim 3, wherein the first signal measurement value is based on a reference signal receiving power (RSRP) value or based on a reference signal receiving quality (RSRQ) value.
The method of Claim 3, wherein the first signal measurement value is determined based on one of the followings:

Ms, wherein the Ms is a RSRP value or a RSRQ value of the serving cell;

Ms+Hys, wherein the Hys is a hysteresis parameter;

Ms+Hys+offset_CEn, wherein the offset_CEn is a CE level specific offset;

Q _rxlevmeas – (Q _rxlevmin + Q _{rxlevminoffset}) –Pcompensation -Qoffset _tem, wherein the Q _rxlevmeas is a RSRP value of a target cell measured by the UE, the Q _rxlevmin is a minimum receiving power level value, Q _{rxlevminoffset} is an offset value of the minimum receiving power level, Pcompensation is a power compensation value, and Qoffset _temp is an addition offset value;

Q _qualmeas – (Q _qualmin + Q _{qualminoffset}) -Qoffset _temp, wherein the Q _qualmeas is a RSRQ value of a target cell measured by the UE, the Q _qualmin is a minimum quality level value, Q _{qualminoffset} is an offset value of the minimum quality level; and

Ms+Ofs+Ocs+Hys+off, wherein the Ofs is a frequency specific offset, Ocs is a cell specific offset, and off is an event specific offset.
The method of Claim 3, wherein the condition is one of:

a first condition that the first signal measurement valueis less than or equal to a threshold value associated with the first CE level of the coverage range in the first set of threshold values;

a second condition that the first signal measurement value is less than or equal to a threshold value associated with the first CE level of the coverage range in the second set of threshold values; and

a third condition that the first signal measurement value is less than or equal to a threshold value associated with the first CE level of the coverage range in the third set of threshold values.
The method of Claim 6, wherein triggering a neighbor cell measurement further comprises one of the followings:

in the case that the first condition is fulfilled, triggering the intra frequency neighbor cell measurement;

in the case that the second condition is fulfilled, triggering the inter frequency neighbor cell measurement; and

in the case that the third condition is fulfilled, triggering the intra frequency neighbor cell measurement and the inter frequency neighbor cell measurement.
The method of claim 1, wherein the measurement configuration information indicates a fourth set of threshold values, each threshold value in the fourth set of threshold values associated with at least one of an intra frequency neighbor cell measurement, an inter frequency neighbor cell measurement, or an intra frequency neighbor cell measurement and an inter frequency neighbor cell measurement.
The method of Claim 8, further comprising:

determining a second signal measurement value of a serving cell of the UE, wherein the second signal measurement value is based on a RSRP value or based on a RSRQ value; and

in the case that the second signal measurement value is less than or equal to a threshold value in the fourth set of threshold values, trigger a corresponding neighbor cell measurement associated with the threshold value.
The method of Claim 9, wherein the second signal measurement value is determined based on one of the followings:

Ms+Hys, wherein the Ms is a RSRP value or a RSRQ value of the serving cell, and wherein the Hys is a hysteresis parameter;

Ms+Hys+offset_CEn, wherein the offset_CEn is a CE level specific offset; and

Ms+Ofs+Ocs+Hys+off, wherein the Ofs is a frequency specific offset, Ocs is a cell specific offset, and off is an event specific offset.
The method of claim 1, wherein the measurement configuration information indicates at least one of:

a fifth set of threshold values and a sixth set of threshold values associated with an intra frequency neighbor cell measurement, each threshold value in the fifth set and sixth set of threshold values associated with a CE level;

a seventh set of threshold values and a eighth set of threshold values associated with an inter frequency neighbor cell measurement, each threshold value in the seventh set and eighth set of threshold values associated with the CE level; and

an ninth set of threshold values and a tenth set of threshold values associated with an intra frequency neighbor cell measurement and an inter frequency neighbor cell measurement, each threshold value in the eighth set and ninth set of threshold values associated with the CE level.
The method of Claim 11, further comprising:

determining a second CE level of a coverage range in which the UE is located; and

determining a third signal measurement value and a fourth signal measurement value of the UE.
The method of Claim 12, wherein the third signal measurement value is based on a RSRP value and the fourth signal measurement value is based on a RSRQ value.
The method of Claim 12, wherein each of the third signal measurement value and the fourth signal measurement value is determined based on one of the followings:

Ms, wherein the Ms is a RSRP value or a RSRQ value of a serving cell;

Ms+Hys, wherein the Hys is a hysteresis parameter;

Ms+Hys+offset_CEn, wherein the offset_CEn is a CE level specific offset;

Q _rxlevmeas – (Q _rxlevmin + Q _{rxlevminoffset}) –Pcompensation -Qoffset _tem, wherein the Q _rxlevmeas is a RSRP value of a target cell measured by the UE, the Q _rxlevmin is a minimum receiving power level value, Q _{rxlevminoffset} is an offset value of the minimum receiving power level, Pcompensation is a power compensation value, and Qoffset _temp is an addition offset value;

Q _qualmeas – (Q _qualmin + Q _{qualminoffset}) -Qoffset _temp, wherein the Q _qualmeas is a RSRQ value of a target cell measured by the UE, the Q _qualmin is a minimum quality level value, Q _{qualminoffset} is an offset value of the minimum quality level; and

Ms+Ofs+Ocs+Hys+off, wherein the Ofs is a frequency specific offset, Ocs is a cell specific offset, and off is an event specific offset.
The method of Claim 12, wherein the condition is one of:

a fourth condition that the third signal measurement value is less than or equal to a threshold value associated with the second CE level in the fifth set of threshold values and that the fourth signal measurement value is less than or equal to a threshold value associated with the second CE level in the sixth set of threshold values;

a fifth condition that the third signal measurement value is less than or equal to a threshold value associated with the second CE level in the seventh set of threshold values and that the fourth signal measurement value is less than or equal to a threshold value associated with the second CE level in the eighth set of threshold values; and

a sixth condition that the third signal measurement value is less than or equal to a threshold value associated with the second CE level in the ninth set of threshold values and that the fourth signal measurement value is less than or equal to a threshold value associated with the second CE level in the tenth set of threshold values.
The method of Claim 15, wherein triggering a neighbor cell measurement further comprises one of the followings:

in the case that the fourth condition is fulfilled, triggering the intra frequency neighbor cell measurement;

in the case that the fifth condition is fulfilled, triggering the inter frequency neighbor cell measurement; and

in the case that the sixth condition is fulfilled, triggering the intra frequency neighbor cell measurement and the inter frequency neighbor cell measurement.
The method of claim 1, wherein the measurement configuration information indicates at least one pair of threshold values, wherein each pair of at least one pair of threshold values is associated with an intra frequency neighbor cell measurement, an inter frequency neighbor cell measurement, or an intra frequency neighbor cell measurement and an inter frequency neighbor cell measurement.
The method of Claim 17, further comprising:

determining a fifth signal measurement value and a sixth signal measurement value of a serving cell of the UE, wherein the fifth signal measurement value is based on a RSRP value and the sixth signal measurement value is based on a RSRQ value; and

in the case that the fifth signal measurement value is less than or equal to one threshold value in a pair of threshold values and the sixth signal measurement value is less than or equal to another threshold value in the pair of threshold values, trigger a corresponding neighbor cell measurement associated with the pair of threshold values.
The method of Claim 18, wherein each of the fifth signal measurement value and the sixth signal measurement value is determined based on one of the followings:

Ms+Hys, wherein the Ms is a RSRP value or a RSRQ value of the serving cell, and wherein the Hys is a hysteresis parameter;

Ms+Hys+offset_CEn, wherein the offset_CEn is a CE level specific offset; and

Ms+Ofs+Ocs+Hys+off, wherein the Ofs is a frequency specific offset, Ocs is a cell specific offset, and off is an event specific offset .
The method of claim 1, wherein the measurement configuration information is configured by a base station (BS) or preconfigured in the UE.
The method of claim 1, wherein the measurement configuration information indicates CE level information for triggering the neighbor cell measurement, and wherein the UE triggers the neighbor cell measurement in the case that the UE is located in a coverage range having the CE level information.
The method of claim 21, wherein the CE level information is indicated to the UE via a dedicated signaling or broadcast information.
The method of claim 21, wherein the CE level information is preconfigured in the UE, and the method further comprises indicating the CE level information to a serving cell of the UE.
The method of claim 1, wherein the condition comprises a CE level changing of the UE.
The method of claim 1, wherein the measurement configuration information indicates a first number of consecutive "out-of-sync" indications.
The method of claim 25, wherein the condition is that the first number of consecutive "out-of-sync" indications for a serving cell is detected by the UE.
The method of claim 25, wherein the condition is that the first number of consecutive "out-of-sync" indications for a serving cell is detected by the UE when a first timer associated with a radio link failure (RLF) is running.
The method of claim 1, wherein the measurement configuration information indicates:

a second number of consecutive "out-of-sync" indications; and

configuration information for a second timer;

wherein the method further comprises:

starting the second timer after receiving the second number of consecutive "out-of-sync" indications for a serving cell when a first timer associated with a RLF is running.
The method of claim 28, further comprising triggering the neighbor cell measurement in the case that the second timer expires.
The method of claim 28, wherein the measurement configuration information indicates a third number of consecutive "in-sync" indications, and wherein the method further comprises: stopping the second timer in the case that third number of consecutive "in-sync" indications for the serving cell is detected or the first timer is stopped.
The method of claim 1, wherein the measurement configuration information indicates configuration information for a third timer, and wherein the method further comprises: starting the third timer when a first timer associated with a RLF is started.
The method of claim 31, further comprising triggering the neighbor cell measurement in the case that the third timer expires.
The method of claim 31, wherein the measurement configuration information indicates a fourth number of consecutive "in-sync" indications, and wherein the method further comprises: stopping the third timer in the case that fourth number of consecutive "in-sync" indications for a serving cell is detected or the first timer is stopped.
The method of claim 1, wherein the measurement configuration information indicates a first time length, and wherein the method further comprises triggering the neighbor cell measurement at a time point when a time that a first timer associated with a RLF is predicted to be expired minus the first time length.
The method of claim 1, wherein the measurement configuration information indicates configuration information for a fourth timer, wherein the methods further comprises:

starting the fourth timer at a time point when a time that a first timer associated with a RLF is predicted to be expired minus the length of the fourth timer.
The method of claim 35, further comprising triggering the neighbor cell measurement in the case that the fourth timer is started.

stopping the fourth timer in the case that the fifth number of consecutive "in-sync" indications for a serving cell is detected or the first timer is stopped.
The method of claim 35, wherein the measurement configuration information indicates a fifth number of consecutive "in-sync" indications, and wherein the method further comprises:

stopping the fourth timer in the case that the fifth number of consecutive "in-sync" indications for a serving cell is detected or the first timer is stopped.
The method of Claim 1, wherein the measurement configuration information indicates at least one signal to interference plus noise ratio (SINR) threshold value, each SINR threshold value associated with a CE level.
The method of claim 1, further comprising stopping the neighbor cell measurement in response to one or more of the followings:

a signal quality of a new cell measured by the UE is higher than or equal to a threshold;

one period or multiple periods for neighbor cell measurement are finished; and

a signal quality of a serving cell of the UE is higher than or equal than to a threshold.
The method of claim 1, wherein the measurement configuration information indicates a sixth number of retransmissions, and wherein the condition is that the sixth number of retransmissions occur in a radio link control (RLC) layer of the UE.
The method of Claim 1, further comprising:

transmitting, to a serving cell of the UE, an assistant message;

wherein the assistant message implicitly or explicitly indicates at least one of the followings:

the UE will trigger the RRC connection re-establishment procedure;

CE level of the target cell to which a RRC connection re-establishment will be transmitted;

cell global identifier (CGI) of the target cell;

CE level of a serving cell;

a measurement value of the serving cell;

CE level of a neighbor cell;

a measurement value of the neighbor cell; and

CGI of the neighbor cell.
The method of claim 41, wherein the assistant message is transmitted via a radio resource control (RRC) signaling or via a media access control (MAC) control element (CE) .
The method of claim 41, wherein the assistant message is transmitted by a preconfigured uplink resource or by a Msg. A in a two-step random access channel (RACH) procedure.
The method of claim 41, wherein the assistant message is transmitted in response to one or more of the followings:

the neighbor cell measurement is finished;

a seventh number of "out-of-sync" indications is detected by the UE; and

a signal quality of a serving cell of the UE is below a threshold.
A method, comprising:

transmitting measurement configuration information to a user equipment (UE) , wherein the measurement configuration information is used for determining a condition for triggering a neighbor cell measurement for at least one neighbor cell before a radio resource control (RRC) connection re-establishment procedure.
The method of claim 45, wherein the measurement configuration information indicates at least one of:

a first set of threshold values associated with an intra frequency neighbor cell measurement, each threshold value in the first set of threshold values associated with a coverage enhancement (CE) level;

a second set of threshold values associated with an inter frequency neighbor cell measurement, each threshold value in the second set of threshold values associated with the CE level; and

a third set of threshold values associated with an intra frequency neighbor cell measurement and an inter frequency neighbor cell measurement, each threshold value in the third set of threshold values associated with the CE level.
The method of Claim 46, wherein the condition is one of:

a first condition that a first signal measurement value is less than or equal to a threshold value associated with a first CE level of a coverage range in which the UE is located in the first set of threshold values;

a second condition that a first signal measurement value is less than or equal to a threshold value associated with the first CE level of a coverage range in which the UE is located in the second set of threshold values; and

a third condition that the first signal measurement value is less than or equal to a threshold value associated with the first CE level of a coverage range in which the UE is located in the third set of threshold values;

wherein the first signal measurement value is based on a reference signal receiving power (RSRP) value or based on a reference signal receiving quality (RSRQ) value.
The method of claim 45, wherein the measurement configuration information indicates a fourth set of threshold values, each threshold value in the fourth set of threshold values associated with an intra frequency neighbor cell measurement, an inter frequency neighbor cell measurement, or an intra frequency neighbor cell measurement and an inter frequency neighbor cell measurement.
The method of Claim 48, wherein the condition is that a second signal measurement value is less than or equal to a threshold value in the fourth set of threshold values, wherein the second signal measurement value is based on a RSRP value or based on a RSRQ value.
The method of claim 45, wherein the measurement configuration information indicates at least one of:

a fifth set of threshold values and a sixth set of threshold values associated with an intra frequency neighbor cell measurement, each threshold value in the fifth set and sixth set of threshold values associated with a CE level;

a seventh set of threshold values and a eighth set of threshold values associated with an inter frequency neighbor cell measurement, each threshold value in the seventh set and eighth set of threshold values associated with the CE level; and

an ninth set of threshold values and a tenth set of threshold values associated with an intra frequency neighbor cell measurement and an inter frequency neighbor cell measurement, each threshold value in the ninth set and tenth set of threshold values associated with the CE level.
The method of Claim 50, wherein the condition is one of:

a fourth condition that a third signal measurement value is less than or equal to a threshold value associated with a second CE level of a coverage range in which the UE is located in the fifth set of threshold values and that the fourth signal measurement value is less than or equal to a threshold value associated with the second CE level in the sixth set of threshold values;

a fifth condition that the third signal measurement value is less than or equal to a threshold value associated with the second CE level of a coverage range in which the UE is located in the seventh set of threshold values and that the fourth signal measurement value is less than or equal to a threshold value associated with the second CE level in the eighth set of threshold values; and

a sixth condition that the third signal measurement value is less than or equal to a threshold value associated with the second CE level of a coverage range in which the UE is located in the ninth set of threshold values and that the fourth signal measurement value is less than or equal to a threshold value associated with the second CE level in the tenth set of threshold values; and

wherein the third signal measurement value is based on a RSRP value and the fourth signal measurement value is based on a RSRQ value.
The method of claim 45, wherein the measurement configuration information indicates at least one pair of threshold values, wherein each pair of at least one pair of threshold values is associated with an intra frequency neighbor cell measurement, an inter frequency neighbor cell measurement, or an intra frequency neighbor cell measurement and an inter frequency neighbor cell measurement.
The method of Claim 52, wherein the condition is that a fifth signal measurement value is less than or equal to one threshold value in a pair of threshold values and the sixth signal measurement value is less than or equal to another threshold value in the pair of threshold values, wherein the fifth signal measurement value is based on a RSRP value and the sixth signal measurement value is based on a RSRQ value.
The method of claim 45, wherein the measurement configuration information indicates a CE level for triggering the neighbor cell measurement.
The method of claim 54, wherein the CE level is indicated to the UE via a dedicated signaling or broadcast information.
The method of claim 45, wherein the condition comprises a CE level changing of the UE.
The method of claim 45, wherein the measurement configuration information indicates a first number of consecutive "out-of-sync" indications.
The method of claim 57, wherein the condition is that the first number of consecutive "out-of-sync" indications for a serving cell is detected by the UE.
The method of claim 57, wherein the condition is that the first number of consecutive "out-of-sync" indications for a serving cell is detected by the UE when a first timer associated with a radio link failure (RLF) is running.
The method of claim 45, wherein the measurement configuration information indicates:

a second number of consecutive "out-of-sync" indications;

configuration information for a second timer; and

wherein the condition is that the second timer expires.
The method of claim 60, wherein the measurement configuration information indicates a third number of consecutive "in-sync" indications.
The method of claim 45, wherein the measurement configuration information indicates configuration information for a third timer, and wherein the condition is that the third timer expires.
The method of claim 62, wherein the measurement configuration information indicates a fourth number of consecutive "in-sync" indications.
The method of claim 45, wherein the measurement configuration information indicates a first time length, and wherein the condition is a time point when a time that a first timer associated with a RLF is predicted to be expired minus the first time length
The method of claim 45, wherein the measurement configuration information indicates configuration information for a fourth timer, wherein the condition is that the fourth timer is started.
The method of claim 65, wherein the measurement configuration information indicates a fifth number of consecutive "in-sync" indications.
The method of Claim 45, wherein the measurement configuration information indicates at least one signal to interference plus noise ratio (SINR) threshold values, each SINR threshold value associated with a CE level.
The method of claim 45, wherein the measurement configuration information indicates a sixth number of retransmissions, and wherein the condition is that the sixth number of retransmissions occur in a radio link control (RLC) layer of the UE.
The method of Claim 45, further comprising:

receiving an assistant message;

wherein the assistant message implicitly or explicitly indicates at least one of the followings:

the UE will trigger the RRC connection re-establishment procedure; and CE level of a target cell to which a RRC connection re-establishment will be transmitted;

cell global identifier (CGI) of the target cell;

CE level of a serving cell;

a measurement value of the serving cell;

CE level of a neighbor cell;

a measurement value of the neighbor cell; and

CGI of the neighbor cell.
The method of claim 69, wherein the assistant message is received via a radio resource control (RRC) signaling or via a media access control (MAC) control element (CE) .
The method of claim 69, wherein the assistant message is received by a preconfigured uplink resource or by a Msg. A in a two-step random access channel (RACH) procedure.
An apparatus, comprising:

at least one non-transitory computer-readable medium having computer executable instructions stored therein;

at least one receiver;

at least one transmitter; and

at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiver and the at least one transmitter;

wherein the computer executable instructions are programmed to implement a method according to any one of Claims 1-44 with the at least one receiver, the at least one transmitter and the at least one processor.
An apparatus, comprising:

at least one non-transitory computer-readable medium having computer executable instructions stored therein;

at least one receiver;

at least one transmitter; and

at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiver and the at least one transmitter;

wherein the computer executable instructions are programmed to implement a method according to any one of Claims 45-71 with the at least one receiver, the at least one transmitter and the at least one processor.