WO2022082376A1

WO2022082376A1 - Cell selection in non-terrestrial network

Info

Publication number: WO2022082376A1
Application number: PCT/CN2020/121965
Authority: WO
Inventors: Pingping Wen; Ping Yuan; Wenjian Wang
Original assignee: Nokia Shanghai Bell Co., Ltd.; Nokia Solutions And Networks Oy; Nokia Technologies Oy
Priority date: 2020-10-19
Filing date: 2020-10-19
Publication date: 2022-04-28
Also published as: CN116325948A

Abstract

Embodiments of the present disclosure relate to cell selection in non-terrestrial network. A method comprises: receiving, at a first device, a first message from a second device managing a source cell of the first device, the first message at least comprising cell selection information for supporting a discontinuous reception or extended discontinuous reception at the first device; and selecting, based on the cell selection information, a target cell for the first device, without measuring on the source cell during a paging transmission window after waking up from a corresponding period of the discontinuous reception or the extended discontinuous reception, the target cell being managed by a third device different from the second device. In this way, a fast and efficient cell selection procedure for terminal devices in RRC idle mode can be implemented in the NTN.

Description

CELL SELECTION IN NON-TERRESTRIAL NETWORK

FIELD

Embodiments of the present disclosure generally relate to the field of telecommunication and in particular, to methods, devices, apparatuses and computer readable storage media for cell selection in non-terrestrial network (NTN) .

BACKGROUND

The Narrow band Internet of Things (NB-IoT) technology aims to support a long battery life for terminal devices in a communication network. Many schemes are designed for the purpose of power saving in NB-IoT, including Power Saving Mode (PSM) , Discontinuous Reception (DRX) and extended DRX (eDRX) . Specifically, eDRX scheme is used by the terminal device in Radio Resource Control (RRC) idle state, with a cycle including a deep sleep period, i.e., an eDRX cycle and a paging transmission window (PTW) . Accordingly, the terminal device operating in the eDRX scheme periodically enters into the deep sleep state and wakes up during the PTW. The eDRX period may range from a minimum value of 10.24s to a maximum value of 10485.76 seconds. After waking up from such a long sleep period, the terminal device is typically engaged in cell measurement activities, which may then trigger cell selection or reselection procedures.

In legacy communication networks that utilize the NB-IoT technology, the terminal devices are usually stationary and with low mobility, and thus cell selection criterion S and cell reselection criterion R are suitable for those communication systems. Now the NB-IoT technology has been adopted in NTNs for provide IoT operations in remote areas with no or low cellular connectivity for multiple industries, such as, transportation and logistics, solar, oil and gas harvesting, utilities, farming, environment monitoring, mining and so on. The coverage of the NTN is provided by one or more non-terrestrial network devices that move with a high speed relative to a fixed position on Earth, such as, Low Earth Orbit (LEO) satellites, High Altitude Platforms (HAPS) , Unmanned Aerospace Surveillance (UAS) platforms, and so on. Taking a NTN deployed with LEO satellite constellation as an example, when a terminal device wakes up from one eDRX cycle, multiple LEO satellites may have spanned over the terminal device. This usually results in frequent and unavoidable handovers (HOs) and cell reselection procedures involving stationary and moving terminal devices, and possibly leads to complex implementations or undesirable overhead.

SUMMARY

In general, example embodiments of the present disclosure provide a solution for cell selection in the NTN.

In a first aspect, there is provided a first device. The first device comprises at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code are configured to, with the at least one processor, cause the first device to receive a first message from a second device managing a source cell of the first device, the first message at least comprising cell selection information for supporting discontinuous reception or extended discontinuous reception at the first device; and select, based on the cell selection information, a target cell for the first device, without measuring on the source cell during a paging transmission window after waking up from a corresponding discontinuous reception cycle or extended discontinuous reception cycle, the target cell being managed by a third device different from the second device.

In a second aspect, there is provided a second device. The second device comprises at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code are configured to, with the at least one processor, cause the second device to: determine cell selection information for supporting discontinuous reception or extended discontinuous reception at a first device, a source cell of the first device being managed by the second device; and transmit, to the first device, a first message at least comprising the cell selection information for causing the first device to select a target cell for the first device without measuring on the source cell during a paging transmission window after waking up from a corresponding discontinuous reception or extended discontinuous reception cycle, the target cell being managed by a third device different from the second device.

In a third aspect, there is provided a method. The method comprises: receiving, at a first device, a first message from a second device managing a source cell of the first device, the first message at least comprising cell selection information for supporting a discontinuous reception or extended discontinuous reception at the first device; and selecting, based on the cell selection information, a target cell for the first device, without measuring on the source cell during a paging transmission window after waking up from a corresponding discontinuous reception or extended discontinuous reception cycle, the target cell being managed by a third device different from the second device.

In a fourth aspect, there is provided a method. The method comprises: determining, at a second device, cell selection information for supporting discontinuous reception or extended discontinuous reception at a first device, a source cell of the first device being managed by the second device; and transmitting, to the first device, a first message at least comprising the cell selection information for causing the first device to select a target cell for the first device without measuring on the source cell during a paging transmission window after waking up from a corresponding discontinuous reception or extended discontinuous reception cycle, the target cell being managed by a third device different from the second device.

In a fifth aspect, there is provided a first apparatus. The first apparatus comprises: means for receiving, at the first apparatus, a first message from a second apparatus managing a source cell of the first device, the first message at least comprising cell selection information for supporting a discontinuous reception or extended discontinuous reception at the first apparatus; and means for selecting, based on the cell selection information, a target cell for the first apparatus, without measuring on the source cell during a paging transmission window after waking up from a corresponding discontinuous reception or extended discontinuous reception cycle, the target cell being managed by a third apparatus different from the second apparatus.

In a sixth aspect, there is provided a second apparatus. The second apparatus comprises: means for determining, at a second apparatus, cell selection information for supporting discontinuous reception or extended discontinuous reception at a first apparatus, a source cell of the first apparatus being managed by the second apparatus; and means for transmitting, to the first apparatus, a first message at least comprising the cell selection information for causing the first apparatus to select a target cell for the first apparatus without measuring on the source cell during a paging transmission window after waking up from a corresponding discontinuous reception or extended discontinuous reception cycle, the target cell being managed by a third apparatus different from the second apparatus.

In a seventh aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to the above third aspect.

In an eighth aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to the above fourth aspect.

It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Some example embodiments will now be described with reference to the accompanying drawings, where:

Fig. 1A illustrates an example communication environment at time instant T ₁ in which embodiments of the present disclosure may be implemented;

Fig. 1B illustrates the example communication environment at time instant T ₂ after the first time instant T ₁ in accordance with some example embodiments of the present disclosure;

Fig. 2 illustrates a schematic diagram of an example eDRX scheme in accordance with some example embodiments of the present disclosure;

Fig. 3 illustrates a signaling flow for cell selection procedure in accordance with some example embodiments of the present disclosure;

Fig. 4 illustrates a flowchart of a method for cell selection in accordance with some example embodiments of the present disclosure;

Fig. 5 illustrates a flowchart of a method cell selection in accordance with some example embodiments of the present disclosure;

Fig. 6 illustrates a simplified block diagram of an apparatus that is suitable for implementing embodiments of the present disclosure; and

Fig. 7 illustrates a block diagram of an example computer readable medium in accordance with some embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

References in the present disclosure to “one embodiment, ” “an embodiment, ” “an example embodiment, ” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It shall be understood that although the terms “first” and “second” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a” , “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” , “comprising” , “has” , “having” , “includes” and/or “including” , when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof.

As used in this application, the term “circuitry” may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and

(b) combinations of hardware circuits and software, such as (as applicable) :

(i) a combination of analog and/or digital hardware circuit (s) with software/firmware and

(ii) any portions of hardware processor (s) with software (including digital signal processor (s) ) , software, and memory (ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

(c) hardware circuit (s) and or processor (s) , such as a microprocessor (s) or a portion of a microprocessor (s) , that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

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

As used herein, the term “communication network” refers to a network following any suitable communication standards, such as New Raido (NR) , Long Term Evolution (LTE) , LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , High-Speed Packet Access (HSPA) , Non-terrestrial network (NTN) , Narrow Band Internet of Things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the future fifth generation (5G) communication protocols, and/or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems, including but not limited to a terrestrial communication system, a non-terrestrial communication system or a combination thereof. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP) , for example, a node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a NR NB (also referred to as a gNB) , a Remote Radio Unit (RRU) , a radio header (RH) , a remote radio head (RRH) , a relay, a low power node such as a femto, a pico, a non-terrestrial network (NTN) or non-ground network device such as a satellite network device, a low earth orbit (LEO) satellite and a geosynchronous earth orbit (GEO) satellite, an aircraft network device, and so forth, depending on the applied terminology and technology.

The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE) , a Subscriber Station (SS) , a Portable Subscriber Station, a Mobile Station (MS) , or an Access Terminal (AT) . The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA) , portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE) , laptop-mounted equipment (LME) , USB dongles, smart devices, wireless customer-premises equipment (CPE) , an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD) , a vehicle, a drone, a medical device and applications (e.g., remote surgery) , an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts) , a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. In the following description, the terms “terminal device” , “communication device” , “terminal” , “user equipment” and “UE” may be used interchangeably.

NB-IoT supports stationary and low-mobility terminal devices mainly operating in RRC idle state, which may be also referred to as NB-IoT terminal devices. As mentioned above, in the DRX and eDRX schemes, a NB-IoT terminal device periodically enters into the deep sleep state during corresponding DRX or eDRX cycles, and wakes up during the PTWs which further includes one or more paging occasions (POs) for monitoring the Narrowband Physical Downlink Control Channel (NPDCCH) . Simultaneously, cell measurement activities, such as measurements of Reference Signal Received Power (RSRP) , Reference Signal Received Quality (RSRQ) related to cell selection and reselection process in idle mode may be performed at the terminal device during the PO.

In legacy communication systems, criteria S and R are widely used in cell selection and reselection procedures. Specifically, at the start of each PO, the terminal device may perform intra-frequency or inter-frequency measurements of RSRPs on its serving cell and neighbor cells. In the context of the present disclosure, the serving cell may also be referred to as a source cell. The criterion S is shown in formular (1) below.

S _rxlev = Q _rxlevmeas –Q _rxlevmin –P _compensation –Q _offset (1)

where S _rxlev represents cell selection received level value (dB) ; Q _rxlevmeas represents the measured cell received level value (e.g., the RSRP) ; Q _rxlevmin represents the minimum received level value required by the cell, P _compensation and Q _offset are values operators, which can be configured or set by the network.

In a case of intra-frequency measurement, if S _rxlev exceeds a threshold for intra-frequency measurements, i.e., S _IntraSearchP, that is, S _rxlev > S _IntraSearchP, the terminal device determines not to perform intra-frequency measurements. Otherwise, if S _rxlev ≤S _IntraSearchP, the terminal device may perform the intra-frequency measurements.

Similarly, In a case of inter-frequency measurement, if the S _rxlev does not exceed a threshold for inter-frequency measurements, i.e., S _{nonIntraSearchP}, that is, S _rxlev ≤S _{nonIntraSearchP}, the terminal device may perform inter-frequency measurements. With the cell selection criterion S, the measurements required for cell reselection can be limited, thus saving power consumption at the terminal device.

As mention above, in the case where S _rxlev is lower than the threshold for intra-frequency measurements S _IntraSearchP, the terminal device measures RSRPs for the serving cell and the neighbor cells at the next cycle, rank the measuring results according to cell reselection criterion R. Serving cell rank Rs and neighbor cell rank Rn, as comparison parameters for cell reselection can be expressed in formulars (2) - (3) below.

Rs = Q _meas, s+ Q _Hyst (2)

Rn = Q _meas, n –Q _offset (3)

where Q _meas, sand Q _meas, n represent the values of RSRPs measured for the serving cell and the neighbor cells, respectively; Q _Hyst represents a hysteresis value of cell reselection and Q _offset represents an offset between the RSRPs measured for the serving cell and a corresponding neighbor cell.

If a cell is ranked as the best cell, the terminal device may perform cell reselection procedure and handover to that cell. In addition, the terminal device may reselect a new serving cell, only if the following conditions are met: 1) the new cell is better ranked than the serving cell during a time interval T _{reselectionRAT}; and 2) more than 1 second has elapsed since the terminal device has camped on the current serving cell.

As communication technologies have evolved to the 5G NR, HO and cell selection/reselection procedures for the terminal device may be performed between NTN cells provided by NTN devices, including but not limited to satellites, such as Low Earth Orbit (LEO) satellites, High Altitude Platforms (HAPS) , Unmanned Aerospace Surveillance (UAS) platforms, and so on. 5G NR NTNs are fundamentally different than terrestrial access networks, and thus new mobility mechanisms and/or triggers may be needed to ensure good performance and minimize the delay for the terminal device.

In the NTN, for example, in a LEO satellite scenario, due to the speed of LEO satellites, it is unlikely for the terminal device to stay in the coverage of a same NTN cell for a long period of time. As such, HO and cell selection/reselection procedures may frequently and unavoidably occur even for stationary terminal devices. The maximum periods of time for a NB-IoT terminal device to remain in a NTN cell with respect to a minimum cell diameter (e.g., 50km) and a maximum cell diameter (e.g., 1000km) and relative speeds, namely, a duration from the time when the terminal device enters a coverage of the NTN cell at one cell edge to the time when the terminal device leaves the coverage at the opposite cell edge, are listed in table 1 below.

Table 1 cell diameters and respective relative speeds of terminal device

As can been seem above, regardless of the mobility of the terminal device, it may remain connected in a same NTN LEO cell of diameter 50 km and 1000 km for a maximum time of 6.61 seconds and 132.38 seconds respectively, due to movement of the LEO satellite. For the NB-IoT, the maximum value of the eDRX cycle is extended to 10485.76 seconds, which is equal to 2.91 hours. It is to be expected that when the terminal device wakes up from an eDRX cycle and attempt to receive paging message during the PTW, multiple LEO satellites may have spanned over the terminal device. In this case, the terminal device has already located outside coverage of the source cell and thus disconnected from the satellite managing the source cell. If the terminal device still performs cell reselection procedure according to the criteria S and R, redundant and unnecessary measurements on serving cell will be performed, leading to a waste of power and an undesirable delay for camping on the target cell.

To reduce power consumption, accelerate the cell selection and/or reselection procedure of the terminal device, and to solve further potential issues, the present disclosure provides a fast and efficient cell reselection mechanism for NB-IoT. In the cell selection/reselection mechanism, the terminal device is configured with cell selection information that indicates a condition for performing a simplified and fast cell selection procedure. If the condition is met, the terminal device will directly perform cell selection procedure without measurement and judgment on the source cell. Otherwise, if the condition is not met, the terminal device may perform cell reselection procedure in a legacy manner. As a result, the delay due to cell selection and/or reselection as well as the power consumption at the terminal device can be decreased.

Fig. 1A and 1B illustrates an example communication environment 100 in which embodiments of the present disclosure may be implemented. Specifically, Fig. 1A shows the communication network 100 at the first time instant T ₁, and Fig. 1B shows the communication network 100 at the second time instant T ₂ after the first time instant T ₁. As shown, the communication network 100 includes a first device 110 and a group of network devices including a second device 120, a third device 130, a fourth device 140, the fifth device 150 and so on. It is also to be understood that the number of network devices, terminal devices and cells shown in Figs. 1A and 1B is given for the purpose of illustration without suggesting any limitations.

The group of network devices may be NTN devices moving around the surface of the Earth. By way of example, the second device 120 to the fifth device 150 may be deployed at a satellite or a UAS platform and assumed to be able to generate one or more beams (e.g., satellite beams) for providing a serving area. The serving area of the second device 120, the third device 130, the fourth device 140 and the fifth device 150 may be called a cell, for example,

cells

122, 132, 142 and 152.

To reduce power consumption, the first device 110 may be a terminal device with low or no mobility and operating in RRC idle state, for example, by using the eDRX scheme. Fig. 2 illustrates a schematic diagram of an example eDRX scheme 200 in accordance with some example embodiments of the present disclosure. As shown in Fig. 2, in the eDRX scheme 200, the first device 110 periodically enters into a deep sleep state in the eDRX cycle 210 and wakes up to receive paging messages during POs 221 to 224 of the PTW 220. During the PTW, the first device 110 monitors a downlink channel, such as the NPDCCH between the first device 110 and a network device currently serving the first device 110, for example, the second device 120. In addition, at the PO 221 to 224, the first device 110 may measure the RSRP and RSRQ related to cell selection or reselection on the cells 122 to 152.

Returning to Figs. 1A and 1B, as mentioned above, the group of network devices are NTN devices moving around the surface of the Earth, such as the LEO satellite constellation. In such cases, each of the NTN devices in the group may serve the first device 110 for a certain serving time. As shown in Fig. 1A, at the first time instant T ₁, the first device 110 locates within the cell 122 and served by the second device 120. In other words, the cell 122 is the source cell of first device 110. As time passes to the second time instant T ₂, which is shown in Fig. 1B, the second device 120 moves away while the third device 130 moves above the first device 110. At this point, the first device 110 locates within the coverage of the third device 130, i.e., the cell 132.

It is to be understood the eDRX scheme and particular configurations are set forth herein as an example and should not be regarded as suggest any limitations on the scope of the present disclosure. In some example embodiments, the DRX scheme or any other power saving scheme, either existed or to be developed in future, are also possible and suitable.

In the communication environment 100 as shown in Figs. 1A and 1B, corresponding NTN devices including the second device 120, the third device 130, the fourth device 140 and the fifth device 150 can communicate data and control information to the first device 110. The first device 110 can also communication data and control information to the corresponding network devices 120 to 150. A link from each of the network device 120 to 150 to the first device 110 is referred to as a downlink (DL) , while a link from the first device 110 to a corresponding one of the network devices 120 to 150 is referred to as an uplink (UL) .

Communications in the communication environment 100 may be implemented according to any proper communication protocol (s) , comprising, but not limited to, cellular communication protocols of the first generation (1G) , the second generation (2G) , the third generation (3G) , the fourth generation (4G) and the fifth generation (5G) and on the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and/or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA) , Frequency Division Multiple Access (FDMA) , Time Division Multiple Access (TDMA) , Frequency Division Duplex (FDD) , Time Division Duplex (TDD) , Multiple-Input Multiple-Output (MIMO) , Orthogonal Frequency Division Multiple (OFDM) , Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and/or any other technologies currently known or to be developed in the future.

In terms of the mobility of the terminal device and the network device, there are several aspects to be concerned, including cell selection, reselection, handover, etc. In accordance with example embodiments of the present disclosure, there is provided a solution of cell selection and reselection for the terminal device in idle state. More specifically, instead of repeatedly performing measurements on the source cell and neighbor cells, the cell selection information is provided to the terminal device for indicating a condition for performing a simplified and fact cell selection procedure. Although the proposed solution is described in a context of NTN scenario, it is to be understood that the solution provided in the example embodiments of the present disclosure are also suitable for legacy terrestrial networks. For example, the proposed solution could also be applicable for the terrestrial scenarios, such as a vehicle in a highway or a train, as well as some HAPS scenarios.

Principle and embodiments of the present disclosure will be described in detail below with reference to Figs. 3 to 5. Fig. 3 illustrates a signaling flow for cell selection process 300 in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the process 300 will be described with reference to Figs. 1A and 1B. The process 300 may involve the first device 110, the second device 120, and the third device 130.

As described above in connection with Figs. 1-2, the first device 110 initially locates in the source cell 122 and served by the second device 120. The second device 120 determines 302 cell selection information for supporting DRX or eDRX at the first device 110. The cell selection information is configured to cause the first device 110 to select a target cell for the first device 110 without measuring on the source cell 122 during a paging transmission window after waking up from a corresponding DRX or eDRX cycle, which will be discussed in details below. The target cell may be managed by a network device different from the second device 120, for example, the third device 130.

In some example embodiments, the cell selection information may be a time threshold associated with at least one serving time of the group of network devices 120 to 150. By way of example, the time threshold may be determined to be a minimum serving time of the serving times of the second device 120, the third device 130, the fourth device 140 and the fifth device 150. Such a time threshold may assist the first device 110 in determining whether it is still in the source cell 122 after waking up from the eDRX cycle. Specifically, in a case the eDRX cycle exceeds the time threshold, it indicates that when the first device 110 wakes up from the eDRX cycle, it is likely to no longer locate within the source cell 122. Otherwise, in a case where the eDRX cycle does not exceed the time threshold, after waking up from the eDRX cycle, the first device 110 may still locate in the source cell 122.

In some other example embodiments, the cell selection information may be an indicator for triggering the selection of the target cell without measuring on the source cell 122. In these embodiments, the second device 120 may determine whether the first device 110 is still within the source cell 122 after the first device 110 wakes from the eDRX cycle, based on the eDRX cycle and the time threshold associated with at least one serving time of the group of network devices 120 to 150. For example, if the second device 120 determines that the eDRX cycle of the first device 110 exceeds the time threshold, the second device 120 may set the indicator to be a first value (e.g., 0) , indicating a direct cell selection procedure without measuring on the source cell 122. If the second device 120 determines that the eDRX cycle of the first device 110 does not exceed the time threshold, the second device 120 may set the indicator to be a second value (e.g., 1) , indicating the first device 110 to perform legacy procedure, for example, first measuring on the source cell 122 and then measuring on neighbor cells according to criteria S and R.

In still other example embodiments, if the second device 120 determines that the eDRX cycle of the first device 110 exceeds the time threshold, the second device 120 may transmit the indicator to the first device 110. Otherwise, if the second device 120 determines that the eDRX cycle of the first device 110 does not exceed the time threshold, no indicator will be transmitted from the second device 120, implicitly indicating the first device 110 to perform legacy procedure.

The second device 120 transmits 304 a first message at least including the cell selection information to the first device 110. In some example embodiments, the second device 120 may broadcast the first message to the first device 110. The first message may include the cell selection information and a group of parameters related to cell reselection including, but not limited to, Q _rxlevmin, P _compensation, Q _offset, the corresponding DRX or eDRX cycle and so on.

Upon receipt of the first message, the first device 110 may store the cell selection information locally and subsequently it enters into the eDRX cycle, that is, in a deep sleep state. After waking up during PTW, for example, the time instant t ₂, the first device 110 may be already out of the cell 122 and locates within the cell 132 provided by the third device 130.

In some example embodiments, the first device 110 determines that it already moves out of the source cell 122 and measurement on the source cell 122 can be omitted based on the cell selection information. In this case, the first device 110 selects 306 a target cell without measuring on the source cell 122 based on the cell selection information. In this example, the target cell is the cell 132 managed by the third device 130. The first device 110 may then perform 308 communications with the third device 130 on the target cell 132. For example, the first device 110 may perform cell search, receive a master information block (MIB) , a system information block (SIB) from the third device 130 and so on. The cell selection procedure may follow any mechanism which is known or to be developed in the future, and thus the related description is omitted here to avoid redundancy.

In a case of absence of the cell selection information, or the cell selection information of the second value, or alternatively the eDRX cycle of the first device 110 being not exceeding the time threshold indicated by the cell selection information, the first device 110 may perform cell search and reselection procedure for determining a target cell. Specifically, the first device 110 may first perform measurements on the source cell 122. For example, the first device 110 may measure RSRP or RSRQ of the source cell 122, and determine whether a cell selection condition is met, for example, by adopting the criterion S. In a case where the cell selection condition is met, e.g., S _rxlev ≤ S _IntraSearchP, the first device 110 then performs cell search and measurements on neighbor cells.

The first device 110 may then select a target cell from the neighbor cells based on the cell search and measurements result. For example, the first device 110 may determine the target cell based on the criterion R. Upon determining the target cell, the first device 110 performs the cell reselection procedure to the target cell. The cell reselection procedure may follow any known or existed mechanism or any mechanism to be developed in the future, and thus the description of which is omitted here to avoid redundancy.

According to the example embodiments of the present disclosure, the cell selection information is provided for assisting terminal devices in determining whether it has moved out the source cell and under the coverage of a new network device, for example, a new satellite before any measurement is performed. As such, redundant measurements and judgments on whether it has moved out of the coverage of the source cell can be avoided. As a result, a fast cell selection and reselection procedure can be achieved at the terminal device with low power consumption.

Fig. 4 illustrates a flowchart of a method 400 cell selection in accordance with some example embodiments of the present disclosure. The method 400 can be implemented at a terminal device, e.g., the first device 110 described with reference to Figs. 1A and 1B. The method 400 may further involve the second device 120 and the third apparatus 130. It is to be understood that the method 400 may include additional acts not shown and/or may omit some acts as shown, and the scope of the present disclosure is not limited in this regard. In addition, it will be appreciated that, although primarily presented herein as being performed serially, at least a portion of the acts of the process 400 may be performed contemporaneously or in a different order than as presented in Fig. 4.

At 410, the first device 110 receives a first message from the second device 120 managing the source cell 122 of the first device 110. The first message at least includes the cell selection information for supporting DRX or eDRX at the first device 110. In some example embodiments, the first message may be broadcasted from the second device 120 and further include a group of a group of parameters related to cell reselection, such as, Q _rxlevmin, P _compensation, Q _offset, the corresponding DRX or eDRX cycle and so on In this case, the cell selection formation is transmitted together with parameters related to cell reselection. In some example other embodiments, the cell selection information may be transmitted separately from the parameters related to cell reselection.

Upon receipt of first message, the first device 110 may store the cell selection information locally, and may then enter into the sleep state during the eDRX cycle. In some example embodiments, after waking up from the eDRX cycle, and the first device 110 may enters in the PTW for receiving paging messages and performing measurement in the radio coverage. In such cases, the first device 110 performs cell selection and reselection procedure based on the cell selection information.

At 420, the first device 110 selects, based on the cell selection information, a target cell 132 without measuring on the source cell 122 during the PTW after waking up from a corresponding DRX cycle or the eDRX cycle. The target cell 132 is managed by the third device 130 different from the second device 120.

In some example embodiments, the cell selection information may include a time threshold associated with at least one serving time of the group of network devices 120 to 150. For example, the time threshold may be determined, by the second device 120, to be a minimum serving time of the serving times for the second device120, the third device 130, the fourth device 140 and the fifth device 150. The first device 110 may compare the eDRX cycle with the time threshold. If the eDRX cycle exceeds the time threshold, which indicates that the first device 110 may not locate within in the source cell 122 after waking up from the eDRX cycle, the first device 110 may select the target cell 132 without measuring on the source cell 122 during the PTW. For example, the first device 110 may skip measurements on the source cell 122, and directly perform cell search and measurements on neighbor cells 132 to 152.

In some example embodiments, the cell selection information may include an indicator for triggering the selection of the target cell without measuring on the source cell 122. For example, the indicator included in the cell selection information may be set to a first value (e.g., 0) to indicate that the eDRX cycle of the first device 110 exceeds the time threshold associated with the serving times of the group of network devices 120 to 150, or simply indicate the cell selection without measuring on the source cell to be performed. In this case, the first device 110 may select the target cell 132 without measuring on the source cell 122 during the PTW.

In the above embodiments, if the indicator is set to a second value (e.g., 1) or alternatively the indicator is absent in the first message, the first device 110 may determine that measuring on the source cell 122 cannot be skipped and the legacy procedure is to be performed.

In some example embodiments, the first device 110 may be a terminal device, the second device 120 and the third device 130 may be network devices, such as, NTN devices deployed at the satellites, UAV and so on.

Fig. 5 illustrates a flowchart of a method 500 cell selection in accordance with some example embodiments of the present disclosure. The method 500 can be implemented at a network device, e.g., the second device 120 described with reference to Figs. 1A and 1B. The method 500 may further involve the first device 110. It is to be understood that the method 500 may include additional acts not shown and/or may omit some acts as shown, and the scope of the present disclosure is not limited in this regard. In addition, it will be appreciated that, although primarily presented herein as being performed serially, at least a portion of the acts of the process 500 may be performed contemporaneously or in a different order than as presented in Fig. 5.

At 510, the second device 120 determines the cell selection information for supporting DRX or eDRX at the first device 110. The source cell 122 of the first device 110 is managed by the second device 120. The cell selection information may include a time threshold associated with at least one serving time of the group of network devices 120 to 150. For example, the second device 120 may determine the time threshold to be the minimum serving time or average serving time of the serving times for the second device 120, the third device 130, the fourth device 140 and the fifth device 150.

In some other example embodiments, the cell selection information may include an indicator for triggering the selection of the target cell without measuring on the source cell 122. The indicator included in the cell selection information may have a first value (e.g., 0) and a second value (e.g., 1) , with the first value indicative of triggering the direct target cell selection without measuring on the source cell and the second value indicative of not triggering such a direct target cell selection and a legacy procedure is to be performed.

Alternatively, in some other example embodiments, in a case where the second device 120 may determine that the eDRX cycle exceeds the time threshold associated with the serving times of the group of the network devices 120 to 150, the second device 120 may transmit the indicator indicative of the direct target cell selection. In a case where the second device 120 may determine that the eDRX cycle does not exceed the time threshold associated with the serving times of the group of the network devices 120 to 150, no indicator will be transmitted from the second device 120.

At 520, the second device 120 transmits the first message including the cell selection information to the first device 110. The cell selection information may cause the first device 110 to select a target cell 132 without measuring on the source cell 122 during the PTW after waking up from a corresponding DRX or eDRX cycle. In this case, the target cell 132 is managed by the third device 130 different from the second device 120.

In some example embodiments, the second device 120 may broadcast the first message to the first device 110. By way of example, the first message may further include a group a group of a group of parameters related to cell reselection, such as, Q _rxlevmin, P _compensation, Q _offset, the corresponding DRX or eDRX cycle and so on. In this case, the cell selection formation is transmitted together with parameters related to cell reselection. For another example, the cell selection information may be transmitted separately from the parameters related to cell reselection. The present disclosure is not limited to this aspect.

In some example embodiments, a first apparatus capable of performing the method 400 may comprise means for performing the respective steps of the method 400. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some example embodiments, the first apparatus comprises: receiving a first message from a second apparatus managing a source cell of the first apparatus, the first message at least comprising cell selection information for supporting a discontinuous reception or extended discontinuous reception at the first apparatus; and means for selecting, based on the cell selection information, a target cell for the first apparatus, without measuring on the source cell during a paging transmission window after waking up from a corresponding discontinuous reception or extended discontinuous reception cycle, the target cell being managed by a third apparatus different from the second apparatus.

In some example embodiments, the means for receiving the first message comprises: means for receiving the first message comprising a group of parameters related to cell reselection and the cell selection information.

In some example embodiments, the cell selection information comprises a time threshold associated with at least one serving time of a group of network devices for serving the first apparatus, and the means for selecting the target cell comprises: means for in accordance with a determination that the corresponding discontinuous reception or extended discontinuous reception cycle exceeds the time threshold, selecting the target cell without measuring on the source cell during the paging transmission window.

In some example embodiments, the time threshold is determined to be a minimum serving time of the at least one serving time of the group of network devices for serving the first apparatus.

In some example embodiments, the cell selection information comprises an indicator for triggering the selection of the target cell without measuring on the source cell, and the means for selecting the target cell comprises: means for in accordance with a determination that the cell selection information comprises the indicator, selecting the target cell without measuring on the source cell during the paging transmission window.

In some example embodiments, the first apparatus is a terminal device, the second apparatus is a network device, and the third apparatus is a further network device.

In some example embodiments, a second apparatus capable of performing the method 500 may comprise means for performing the respective steps of the method 500. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some example embodiments, the second apparatus comprises: means for determining cell selection information for supporting discontinuous reception or extended discontinuous reception at a first apparatus, a source cell of the first apparatus being managed by the second apparatus; and means for transmitting, to the first apparatus, a first message at least comprising the cell selection information for causing the first apparatus to select a target cell for the first apparatus without measuring on the source cell during a paging transmission window after waking up from a corresponding discontinuous reception or extended discontinuous reception cycle, the target cell being managed by a third apparatus different from the second apparatus.

In some example embodiments, the cell selection information comprises a time threshold associated with at least one serving time of a group of network devices for serving the first apparatus, and means for determining the cell selection information comprises: means for determining the time threshold based on the at least one serving time of the group of network devices.

In some example embodiments, the means for determining the time threshold comprises: means for determining the time threshold to be a minimum serving time of the at least one serving time of the group of network devices for serving the first apparatus.

In some example embodiments, the cell selection information comprises an indicator for triggering the selection of the target cell without measuring on the source cell, and the means for determining the cell selection information comprises: means for determining a time threshold based on at least one serving time of a group of network devices for serving the first apparatus; and means for in accordance with a determination that the corresponding discontinuous reception or extended discontinuous reception cycle exceeds the time threshold, determining an indicator for triggering the selection of the target cell without measuring on the source cell during the paging transmission window.

In some example embodiments, the means for transmitting the first message comprises: means for transmitting the first message comprising the cell selection information and a group of parameters related to cell reselection.

Fig. 6 is a simplified block diagram of a device 600 that is suitable for implementing embodiments of the present disclosure. The device 600 may be provided to implement the communication device, for example the first device 110, the second device 120 and the third device 130, as shown in Figs. 1A and 1B. As shown, the device 600 includes one or more processors 610, one or more memories 620 coupled to the processor 610, and one or more communication modules 640 coupled to the processor 610.

The communication module 640 is for bidirectional communications. The communication module 640 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.

The processor 610 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 600 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

The memory 620 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 624, an electrically programmable read only memory (EPROM) , a flash memory, a hard disk, a compact disc (CD) , a digital video disk (DVD) , and other magnetic storage and/or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 622 and other volatile memories that will not last in the power-down duration.

A computer program 630 includes computer executable instructions that are executed by the associated processor 610. The program 630 may be stored in the ROM 620. The processor 610 may perform any suitable actions and processing by loading the program 630 into the RAM 620.

The embodiments of the present disclosure may be implemented by means of the program 630 so that the device 600 may perform any process of the disclosure as discussed with reference to Figs. 3 to 5. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

In some embodiments, the program 630 may be tangibly contained in a computer readable medium which may be included in the device 600 (such as in the memory 620) or other storage devices that are accessible by the device 600. The device 600 may load the program 630 from the computer readable medium to the RAM 622 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. Fig. 7 shows an example of the computer readable medium 700 in form of CD or DVD. The computer readable medium has the program 630 stored thereon.

Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the

method

400 or 500 as described above with reference to Figs. 4-5. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in languages specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

A first device, comprising:

at least one processor; and

at least one memory including computer program code;

wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the first device at least to:

receive a first message from a second device managing a source cell of the first device, the first message at least comprising cell selection information for supporting discontinuous reception or extended discontinuous reception at the first device; and

select, based on the cell selection information, a target cell for the first device, without measuring on the source cell during a paging transmission window after waking up from a corresponding discontinuous reception cycle or extended discontinuous reception cycle, the target cell being managed by a third device different from the second device.
The first device of Claim 1, wherein the first device is caused to receive the first message by:

receiving the first message comprising a group of parameters related to cell reselection and the cell selection information.
The first device of Claim 1, wherein the cell selection information comprises a time threshold associated with at least one serving time of a group of network devices for serving the first device, and wherein the first device is caused to select the target cell by:

in accordance with a determination that the corresponding discontinuous reception or the extended discontinuous reception cycle exceeds the time threshold, selecting the target cell without measuring on the source cell during the paging transmission window.
The first device of Claim 3, wherein the time threshold is determined to be a minimum serving time of the at least one serving time of the group of network devices for serving the first device.
The first device of Claim 1, wherein the cell selection information comprises an indicator for triggering the selection of the target cell without measuring on the source cell, and wherein the first device is caused to select the target cell by:

in accordance with a determination that the cell selection information comprises the indicator, selecting the target cell without measuring on the source cell during the paging transmission window.
The first device of Claim 1, wherein the first device is a terminal device, the second device is a network device, and the third device is a further network device.
A second device, comprising:

at least one processor; and

at least one memory including computer program code;

wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the second device at least to:

determine cell selection information for supporting discontinuous reception or extended discontinuous reception at a first device, a source cell of the first device being managed by the second device; and

transmit, to the first device, a first message at least comprising the cell selection information for causing the first device to select a target cell for the first device without measuring on the source cell during a paging transmission window after waking up from a corresponding discontinuous reception or extended discontinuous reception cycle, the target cell being managed by a third device different from the second device.
The second device of Claim 7, wherein the cell selection information comprises a time threshold associated with at least one serving time of a group of network devices for serving the first device, and wherein the second device is caused to determine the cell selection information by:

determining the time threshold based on the at least one serving time of the group of network devices.
The second device of Claim 8, wherein the second device is caused to determine the time threshold by:

determining the time threshold to be a minimum serving time of the at least one serving time of the group of network devices for serving the first device.
The second device of Claim 7, wherein the cell selection information comprises an indicator for triggering the selection of the target cell without measuring on the source cell, and wherein the second device is caused to determine the cell selection information by:

determining a time threshold based on at least one serving time of a group of network devices for serving the first device; and

in accordance with a determination that the corresponding discontinuous reception or extended discontinuous reception cycle exceeds the time threshold, determining an indicator for triggering the selection of the target cell without measuring on the source cell during the paging transmission window.
The second device of Claim 7, wherein the second device is caused to transmit the first message by:

transmitting the first message comprising the cell selection information and a group of parameters related to cell reselection.
The second device of Claim 7, wherein the first device is a terminal device, the second device is a network device, and the third device is a further network device.
The method comprising:

receiving, at a first device, a first message from a second device managing a source cell of the first device, the first message at least comprising cell selection information for supporting a discontinuous reception or extended discontinuous reception at the first device; and

selecting, based on the cell selection information, a target cell for the first device, without measuring on the source cell during a paging transmission window after waking up from a corresponding discontinuous reception or extended discontinuous reception cycle, the target cell being managed by a third device different from the second device.
The method of Claim 13, wherein receiving the first message comprises:

receiving the first message comprising a group of parameters related to cell reselection and the cell selection information.
The method of Claim 13, wherein the cell selection information comprises a time threshold associated with at least one serving time of a group of network devices for serving the first device, and wherein selecting the target cell comprises:

in accordance with a determination that the corresponding discontinuous reception or extended discontinuous reception cycle exceeds the time threshold, selecting the target cell without measuring on the source cell during the paging transmission window.
The method of Claim 15, wherein the time threshold is determined to be a minimum serving time of the at least one serving time of the group of network devices for serving the first device.
The method of Claim 13, wherein the cell selection information comprises an indicator for triggering the selection of the target cell without measuring on the source cell, and wherein selecting the target cell comprises:

in accordance with a determination that the cell selection information comprises the indicator, selecting the target cell without measuring on the source cell during the paging transmission window.
The method of Claim 13, wherein the first device is a terminal device, the second device is a network device, and the third device is a further network device.
A method comprising:

determining, at a second device, cell selection information for supporting discontinuous reception or extended discontinuous reception at a first device, a source cell of the first device being managed by the second device; and

transmitting, to the first device, a first message at least comprising the cell selection information for causing the first device to select a target cell for the first device without measuring on the source cell during a paging transmission window after waking up from a corresponding discontinuous reception or extended discontinuous reception cycle, the target cell being managed by a third device different from the second device.
The method of Claim 19, wherein the cell selection information comprises a time threshold associated with at least one serving time of a group of network devices for serving the first device, and wherein determining the cell selection information comprises:

determining the time threshold based on the at least one serving time of the group of network devices.
The method of Claim 20, wherein determining the time threshold comprises:

determining the time threshold to be a minimum serving time of the at least one serving time of the group of network devices for serving the first device.
The method of Claim 19, wherein the cell selection information comprises an indicator for triggering the selection of the target cell without measuring on the source cell, and wherein determining the cell selection information comprises:

determining a time threshold based on at least one serving time of a group of network devices for serving the first device; and

in accordance with a determination that the corresponding discontinuous reception or extended discontinuous reception cycle exceeds the time threshold, determining an indicator for triggering the selection of the target cell without measuring on the source cell during the paging transmission window.
The method of Claim 19, wherein transmitting the first message comprises:

transmitting the first message comprising the cell selection information and a group of parameters related to cell reselection.
The method of Claim 19, wherein the first device is a terminal device, the second device is a network device, and the third device is a further network device.
A first apparatus, comprising:

means for receiving, at the first apparatus, a first message from a second apparatus managing a source cell of the first device, the first message at least comprising cell selection information for supporting a discontinuous reception or extended discontinuous reception at the first apparatus; and

means for selecting, based on the cell selection information, a target cell for the first apparatus, without measuring on the source cell during a paging transmission window after waking up from a corresponding discontinuous reception or extended discontinuous reception cycle, the target cell being managed by a third apparatus different from the second apparatus.
A second apparatus, comprising:

means for determining, at a second apparatus, cell selection information for supporting discontinuous reception or extended discontinuous reception at a first apparatus, a source cell of the first apparatus being managed by the second apparatus; and

means for transmitting, to the first apparatus, a first message at least comprising the cell selection information for causing the first apparatus to select a target cell for the first apparatus without measuring on the source cell during a paging transmission window after waking up from a corresponding discontinuous reception or extended discontinuous reception cycle, the target cell being managed by a third apparatus different from the second apparatus.
A non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method of any of Claims 13-18.
A non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method of any of Claims 19-24.