COMMUNICATION DEVICES, INFRASTRUCTURE EQUIPMENT AND PROCEDURES

Abstract

A method for operating source infrastructure equipment of a wireless communications network in a conditional handover is provided. The method includes configuring one or more conditions for triggering a handover of a communications device from a source cell provided by the source infrastructure equipment to a target cell provided by target infrastructure equipment of the wireless communications network. The method includes transmitting, to the communications device, an indication of the one or more conditions for triggering the handover of the communications device from the source cell to the target cell. The method includes determining that a network power saving mode, NES, of at least one of the source cell and the target cell has changed or is expected to change. In response, the method includes transmitting an evaluation trigger signal to the communications device.The evaluation trigger signal indicates to the communication device to evaluate one or more of the conditions for triggering the handover of the communication device from the source cell to the destination cell.

Description

BACKGROUND area

[0001] The present disclosure relates to communication devices, infrastructure equipment of a wireless communication network, and methods for operating communication devices and infrastructure equipment of a wireless communication network in a conditional handover.

[0002] The present application claims priority from the Paris Convention of European patent application number EP22216609.2, the contents of which are incorporated herein by reference. Description of the state of the art

[0003] The "background" description provided here serves the purpose of generally outlining the context of the disclosure. Works of the inventors mentioned herein, insofar as they are described in this background section, as well as aspects of the description that might not otherwise be considered prior art at the time of filing, are neither expressly nor implicitly acknowledged as prior art with respect to the present invention.

[0004] Third- and fourth-generation mobile telecommunications systems, such as those based on the 3GPP-defined UMTS and LTE (LTE: Long Term Evolution) architectures, are capable of supporting more sophisticated services than the basic voice and messaging services offered by earlier generations of mobile telecommunications systems. With the improved radio interface and higher data rates provided by LTE systems, users can, for example, utilize high-data-rate applications such as mobile video streaming and mobile video conferencing, which were previously only available via a fixed-line data connection. The demand for such networks is therefore high, and it is expected that the coverage area of ​​these networks—that is, the geographical locations where network access is possible—will continue to expand rapidly.

[0005] Future wireless communication networks are expected to routinely and efficiently support communication with a wider range of devices associated with a broader spectrum of traffic profiles and types than current systems are optimized to support. For example, future wireless communication networks are expected to efficiently support communication with devices including low-complexity devices, machine-type communication (MTC) devices, high-resolution video displays, virtual reality headsets, and so on. Some of these different device types can be deployed in very large numbers, such as low-complexity devices supporting the Internet of Things, and can typically be associated with the transmission of relatively small amounts of data with comparatively high latency tolerance.

[0006] Against this background, future wireless communication networks, such as those that can be described as 5G or New Radio (NR) / New Radio Access Technology (RAT) systems [1], as well as future versions or releases of existing systems, are expected to efficiently support connectivity for a wide variety of devices with different applications and characteristic traffic profiles. Device connectivity is conventionally maintained through so-called "handover" procedures, in which a communication device changes its access point to a wireless communication network in response to a instruction from the wireless communication network or upon fulfillment of one or more conditions. Given the wide variety of device types and capabilities in future wireless communication networks, there is a need for improved handover procedures. SUMMARY

[0007] The present disclosure may help to resolve or reduce at least some of the problems discussed above.

[0008] Exemplary embodiments can provide a method for operating source infrastructure equipment of a wireless communications network in a conditional handover. The method includes configuring one or more conditions to trigger a handover of a communications device from a source cell provided by the source infrastructure equipment to a target cell provided by destination infrastructure equipment of the wireless communications network. The method includes transmitting to the communications device an indication of the one or more conditions to trigger the handover of the communications device from the source cell to the target cell. The method includes determining that a network energy-saving mode (NES) of the source cell and / or the target cell has changed or is expected to change. In response, the method includes transmitting an evaluation trigger signal to the communications device.The evaluation trigger signal indicates to the communication device to evaluate one or more of the conditions for triggering the handover of the communication device from the source cell to the target cell.

[0009] Exemplary embodiments may further provide a method for operating a communication device in a conditional handover. The method comprises receiving, from source infrastructure equipment of a wireless communication network, an indication of one or more conditions for triggering a handover of the communication device from a source cell provided by the source infrastructure equipment to a target cell provided by a destination infrastructure of the wireless communication network. The method also comprises receiving, from the source infrastructure equipment, an evaluation trigger signal indicating to the communication device to evaluate one or more of the conditions for triggering the handover of the communication device from the source cell to the target cell.The evaluation trigger signal is received by the communication device from the source infrastructure equipment in response to a change or anticipated change in a network energy saving mode (NES) of the source cell and / or the destination cell. In response, the method includes evaluating one or more of the conditions to trigger the handover of the communication device from the source cell to the destination cell. The method includes determining that one or more of the evaluated conditions are satisfied. In response, the method includes initiating the handover of the communication device from the source cell to the destination cell.

[0010] Embodiments can provide an energy-efficient conditional handover in a wireless communication network by transmitting an evaluation trigger signal to the communication device in response to the determination that the NES mode of the source and / or destination cell has changed or is expected to change. The transmission of the evaluation trigger signal allows the wireless communication network to control when the communication device evaluates one or more of the conditions for a handover based on a change or expected change in the NES mode of the source and / or destination cell. Because the communication device evaluates one or more conditions in response to receiving the evaluation trigger signal (rather than the periodic or continuous evaluation typical of a conventional conditional handover), it is expected that before a positive evaluation result is reached (i.e.,(the determination that one or more conditions are met) means that fewer evaluations are performed, thereby reducing energy consumption in the wireless communication network. Furthermore, as will be evident from the following detailed description, transmitting the evaluation trigger signal in response to the determination that the NES mode has changed or is expected to change in the source and / or destination cell means that communication devices are able to switch cells (or remain in a cell) in response to changes or expected changes in NES modes. For example, the wireless communication network can efficiently control which communication devices are located in which cells in response to changes in NES modes, for instance, according to a network planning strategy.

[0011] Respective aspects and features of the present disclosure are defined in the attached claims.

[0012] It is understood that both the preceding general description and the following detailed description are examples of the present technology but do not limit it. The described embodiments, along with further advantages, are best understood by referring to the following detailed description in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] A more comprehensive understanding of the revelation and its many associated benefits is quickly achieved when it is better understood by referring to the detailed description below, when viewed in conjunction with the accompanying drawings, where in the multiple views the same reference numerals denote identical or corresponding parts, and: Fig. Figure 1 schematically represents some aspects of an LTE-type wireless telecommunications system that can be configured to operate according to certain embodiments of the present disclosure; Fig. Figure 2 schematically represents some aspects of a wireless telecommunications system using New Radio Access Technology (RAT), which can be configured to operate according to certain embodiments of the present disclosure; Fig. 3 is a schematic block diagram of an example of source infrastructure equipment that controls the handover of a communication device to a destination infrastructure equipment; Fig. Figure 4 schematically illustrates aspects of a conventional handover procedure; Fig.Figure 5 is a flowchart that illustrates a method for operating source infrastructure equipment of a wireless communication network in a conditional handover according to exemplary embodiments; Fig. Figure 6 is a flowchart that illustrates a method for operating a communication device in a conditional handover according to exemplary embodiments. DETAILED DESCRIPTION OF THE EXECUTION FORMS: Long-Term Evolution Advanced Wireless Access Technology (4G)

[0014] Fig. Figure 1 provides a schematic diagram illustrating a basic functionality of a mobile telecommunications network / system 100, which generally operates according to LTE principles but can also support other radio access technologies and can be configured to implement embodiments of the disclosure as described herein. Various elements of Fig.1 and certain aspects of their respective modes of operation are generally known and defined in the relevant standards managed by the 3GPP-(RTM) committee, and also described in many books on this subject, for example Holma H. ​​and Toskala A. [2]. It is understood that operational aspects of the telecommunications networks discussed here that are not specifically described (for example, with regard to specific communication protocols and physical channels for communication between different elements) can be implemented according to any known techniques, for example, according to the relevant standards and known proposed amendments and additions to / to the relevant standards.

[0015] The network 100 comprises a plurality of base stations 101 connected to a core network section 102. Each base station provides a coverage area 103 (e.g., a cell) within which data can be sent to and from communication devices 104. Data is transmitted from the base stations 101 to the communication devices 104 within their respective coverage areas 103 via a radio downlink. Data is transmitted from the communication devices 104 to the base stations 101 via a radio uplink. The core network section 102 forwards data to the communication devices 104 via the respective base stations 101 and provides functions such as authentication, mobility management, charging, and so on. Communication devices can also be referred to as mobile stations, user equipment (UE), user terminals, mobile radios, terminal devices, and so on.Base stations, which represent an example of network infrastructure equipment / network access nodes, may also be referred to as transceiver stations / nodeBs / e-nodeBs / g-nodeBs (gNB), and so on. In this respect, different terminology is often associated with different generations of wireless telecommunications systems for elements that provide largely comparable functionality. However, embodiments of the disclosure can be implemented equally well in different generations of wireless telecommunications systems, such as 5G or New Radio, as explained below, and for the sake of simplicity, a particular terminology may be used regardless of the underlying network architecture.That is to say, the use of a specific term in relation to certain exemplary implementations should not imply that these implementations are limited to a certain network generation that might be most readily associated with that particular terminology. New Radio radio access technology (5G)

[0016] Fig. Figure 2 is a schematic diagram illustrating a network architecture for a New-RAT wireless communication network / system 200 based on previously proposed approaches, which may also be configured to provide functionality according to embodiments of the disclosure described herein. The in Fig.The New RAT network 200 shown in Figure 2 comprises a first communication cell 201 and a second communication cell 202. Each communication cell 201, 202 includes a control node (centralized unit) 221, 222 communicating with a core network component 210 via a respective wired or wireless link 251, 252. The respective control nodes 221, 222 also communicate with several distributed units (radio access nodes / remote transmit and receive points (TRPs)) 211, 212 in their respective cells. This communication can again take place via respective wired or wireless links. The distributed units 211, 212 are responsible for providing the radio access interface for communication devices connected to the network.Each distributed unit 211, 212 has a coverage area (radio access area) 241, 242, the sum of the coverage areas of the distributed units under the control of a control node defining the coverage of the respective communication cells 201, 202. Each distributed unit 211, 212 comprises a transceiver circuit for transmitting and receiving wireless signals and a processor circuit designed to control the respective distributed units 211, 212.

[0017] With regard to its comprehensive top-level functionality, the core network component 210 of the in Fig. The new RAT telecommunications system shown in section 2 can generally be considered to be such that it corresponds to the one described in Fig.1 corresponds to the core network 102 shown, and the respective control nodes 221, 222 and their associated distributed units / TRPs 211, 212 can be broadly considered to provide functionality that corresponds to the base stations 101 of Fig. 1 corresponds to. The term network infrastructure equipment or access node can be used to include these elements and more conventional base station-type elements of wireless communication systems. Depending on the application, the responsibility for scheduling transmissions planned on the radio interface between the respective distributed units and the communication devices may lie with the control node / centralized unit and / or the distributed units / TRPs.

[0018] A communication device or a UE 260 is used in Fig.2 within the coverage area of ​​the first communication cell 201. This communication device 260 can thus exchange a signal with the first control node 221 in the first communication cell via one of the distributed units 211 associated with the first communication cell 201. In some cases, communication for a given communication device is directed by only one of the distributed units, but it is understood that in some other implementations, communication associated with a given communication device can be directed by more than one distributed unit, for example in a soft handover scenario and other scenarios.

[0019] In the example of Fig.For the sake of simplicity, Figure 2 shows two communication cells 201, 202 and one communication device 260, but it is understood that in practice the system can of course include a larger number of communication cells (each supported by a respective control node and a plurality of distributed units) serving a larger number of communication devices.

[0020] It goes without saying that Fig. 2 merely represents an example of a proposed architecture for a new RAT communication system in which approaches according to the principles described herein can be applied, and the functionality disclosed herein can also be applied to wireless communication systems which have other architectures.

[0021] Therefore, embodiments of the disclosure, as discussed here, can be implemented in wireless telecommunications systems / networks according to various other architectures, such as those in Fig. 1 and Fig.The two exemplary architectures shown are implemented. It is therefore understood that the specific wireless communication architecture in any given implementation is not of primary importance for the principles described here. In this respect, embodiments of the disclosure can generally be described in the context of communication between network infrastructure equipment / access node and a communication device, the specific nature of the network infrastructure equipment / access node and the communication device depending on the network infrastructure for the present implementation. For example, in some scenarios, the network infrastructure equipment / access node may include a base station, such as an LTE-type Base Station 101, as shown in Fig.1 shown, which is configured to provide functionality according to the principles described herein, and in other examples the network infrastructure equipment / access node may be a control unit / control node 221, 222 and / or a TRP 211, 212 of the in Fig. 2 of the type shown, which is configured to provide functionality according to the principles described here.

[0022] A detailed illustration of a wireless communication network in which a handover (HO) can be performed is shown in Fig. 3 shown. As shown. Fig. As can be seen in Figure 3, a communication device 502 is transferred from a source infrastructure equipment to a destination infrastructure equipment 504, which is part of a radio access network, to a core network 506. The source and destination cells are in Fig.3 is not shown for the sake of clarity, although it is evident that the source and target cells essentially correspond to the one in relation to the Fig. 1 and Fig. The two cells described above, 3 and 12, can correspond to each other. The source infrastructure equipment (source IE) 504 and the destination infrastructure equipment (destination IE) 506 are part of a radio access network to a core network 508. As can be seen, the communication device 502 is an example of a communication device such as the communication device 260 of the Fig. 2. The communication device 502 can be a UE in one example.

[0023] Prior to the handover, the communication device 502 transmits signals on an uplink UL and receives signals on a downlink DL from a source infrastructure equipment 504. The source infrastructure equipment 504 and the destination infrastructure equipment 506 can each be considered a gNB 101 or a combination of a control node 221 and a TRP 211. Prior to the handover, the communication device 502 is shown transmitting uplink data to the source infrastructure equipment 504 via uplink resources UL of a wireless access interface, as generally illustrated by the dashed arrow 274b.The communication device 502 can likewise be configured to receive downlink data transmitted by the source infrastructure equipment 504 via downlink resources DL, as indicated by the dashed arrow 288b from the source infrastructure equipment 504 to the communication device 502. After handover, the communication device 502 is shown to transmit uplink data via uplink resources (UL) of a wireless access interface to the destination infrastructure equipment 506, as generally represented by the solid arrow 288a to the destination infrastructure equipment 506. The communication device 502 can likewise be configured to receive downlink data transmitted by the destination infrastructure equipment 506 via downlink resources DL, as indicated by the solid arrow 274a from the destination infrastructure equipment 506 to the communication device 502.

[0024] In Fig.3. The source and destination infrastructure equipment 504, 506 are each connected via interfaces 278, 279 to a core network 508, which leads to a controller 504c, 506c of the respective infrastructure equipment 504. The source and destination infrastructure equipment 504, 506 each contain a receiver 504b, 506b, which is connected to an antenna 504d, 506d, and a transmitter 504a, 506a, which is connected to the antenna 504d, 506d. Accordingly, the communication device 502 contains a controller 502c, which is connected to a receiver 502b, which receives signals from an antenna 502d, and a transmitter 502a, which is also connected to the antenna 502d.

[0025] The 504c and 506c controllers are configured to control the source and destination infrastructure equipment, respectively, 504 and 506, and may include a processor circuit, which in turn may comprise various subunits / subcircuits to provide functionality, as further explained herein. These subunits may be implemented as discrete hardware elements or as suitably configured functions of the processor circuit. Thus, the 504c and 506c controllers may include circuits appropriately configured / programmed to provide the desired functionality using conventional programming / configuration techniques for equipment in wireless telecommunications systems. The 504a and 506a transmitters and the 504b and 506b receivers may include signal processing and a radio frequency filter, amplifiers, and circuitry in accordance with conventional arrangements.The transmitters 504a, 506a and the receivers 504b, 506b and the controllers 504c, 506c are shown in for the sake of simplicity. Fig. 3 are schematically represented as separate elements. However, it is understood that the functionality of these elements can be provided in many different ways, for example, using one or more suitably programmed programmable computers, or one or more suitably configured application-specific integrated circuits / circuit arrangements / chips / chipsets. As is understood, the infrastructure equipment 504 will generally include various other elements associated with its operational functionality.

[0026] Accordingly, the controller 502c of the communication device 502 is configured to control the transmitter 502a and the receiver 502b, and may include a processor circuit which, in turn, may include various subunits / subcircuits for providing functionality, as further explained herein. These subunits may be implemented as discrete hardware elements or as suitably configured functions of the processor circuit. Thus, the controller 502c may include a circuit appropriately configured / programmed to provide the desired functionality using conventional programming / configuration techniques for equipment in wireless telecommunications systems. Likewise, the transmitter 502a and the receiver 502b may include signal processing and radio frequency filters, amplifiers, and circuitry in accordance with conventional arrangements.The transmitters 502a, receivers 502b and controllers 502c are shown in for the sake of simplicity. Fig. 3 are schematically represented as separate elements. However, it is understood that the functionality of these elements can be provided in many different ways, for example, by using one or more suitably programmed programmable computers, or one or more suitably configured application-specific integrated circuits / circuit arrangements / chips / chipsets. It is understood that the communication device 502 generally includes various other elements associated with its operational functionality, for example, a power source, a user interface, and so on, but these are shown schematically for the sake of simplicity in Fig. 3 are not shown.

[0027] The 504c and 502c controllers can be configured to execute instructions stored on a computer-readable medium, such as non-volatile memory. The processing steps described here can be performed, for example, by a microprocessor in conjunction with random-access memory, operating in accordance with instructions stored on a computer-readable medium. Traditional conditional handover

[0028] Aspects of NR address mobility improvements, particularly increasing mobility robustness for new services requiring low latency and high reliability (such as URLLC). Situations may arise where a cell currently serving a user endpoint (UE) may no longer be suitable, or where a radio link between the UE and a source gNB providing coverage within the cell is compromised. In such situations, it is generally desirable for the user endpoint (UE) to hand over to a cell of a destination gNB serving it. One way to configure a user endpoint handover from a source gNB to a destination gNB is known as a "conditional handover."

[0029] An example of a conditional handover is in Fig. 4 shown, which was taken from [3], the contents of which are hereby fully incorporated by reference. Fig.Figure 4 schematically represents the communication in a wireless communication network between the communication device 502, the source infrastructure equipment 504, the destination infrastructure equipment 506, another potential destination infrastructure equipment 511, an access mobility and mobility management function (AMF) 512, and a user plane function (UPF) 514. Fig. 4. The source infrastructure equipment 504, the destination infrastructure equipment 506, and other potential destination infrastructure equipment 511 are represented as "gNBs," although it is acknowledged that other infrastructure equipment of a wireless communications network may also be used (for example, eNBs). The AMF 512 and the UPF 514 are functions in a core network of the wireless communications network (such as the core network 508).

[0030] As in Fig.As shown in Figure 4, prior to a handover, the communication device 502 communicates payload data with the AMF 512 and the UPF 514 via the source infrastructure equipment 504. In step 0, the AMF 512 provides mobility control information to the source infrastructure equipment 504. In step 1, the communication device 502 reports measured values ​​to the source infrastructure equipment 504. Such measured values ​​may include measurements performed by the communication device 502, such as reference signal received power (RSRP), reference signal received quality (RSRQ), and / or signal-to-interference ratio (SINR) of reference signals from the source infrastructure equipment 504, the destination infrastructure equipment 506, and / or other potential destination infrastructure equipment 511.In step 2, the source infrastructure equipment 504 determines to configure the communication device 502 for a conditional handover. In step 3, the source infrastructure equipment 504 transmits a handover request to the target infrastructure equipment 506 and the other potential target infrastructure equipment 511. In response, in step 4, the target infrastructure equipment 506 and the other potential target infrastructure equipment 511 perform access control. Subsequently, in step 5, the target infrastructure equipment 506 and the other potential target infrastructure equipment 511 transmit an acknowledgment of the handover request to the source infrastructure equipment 504. Upon receiving the acknowledgment of the handover request, in step 6, the source infrastructure equipment 504 transmits a conditional handover configuration message to the communication device 502.The conditional handover configuration message can be a radio resource control (RRC) configuration message. The conditional handover configuration message contains one or more conditions for triggering a handover of the communication device 502 from a source cell provided by the source infrastructure equipment 504. For example, the one or more conditions in the conditional handover configuration message can include one or more conditions that must be met to trigger a handover to a destination cell provided by the destination infrastructure equipment 506, as well as one or more other conditions that must be met to trigger a handover to other destination cells provided by other potential destination infrastructure equipment 511. The conditions contained in the conditional handover configuration message are explained in more detail below.Upon receiving the conditional handover configuration message, the communication device 502 transmits an RRC reconfiguration completion message to the source infrastructure equipment 504. After receiving the conditional handover configuration message, the communication device 502 can continuously or periodically evaluate the conditions contained in the handover configuration message to determine whether the conditions for triggering the handover are met. If the communication device 502 determines that the conditions for triggering the handover are met, the communication device 502 initiates the handover. For example, the communication device 502 disconnects from the source cell provided by the source infrastructure equipment 504 and connects to the destination cell provided by the destination infrastructure equipment 506. Fig.In the example shown in Figure 4, the communication device 502 determines that the conditions for triggering a handover to the target infrastructure equipment 506 are met. While the communication device 502 evaluates the conditions, in step 7a, the source infrastructure equipment 604 transmits an early status transfer to the other potential target infrastructure equipment, and subsequent payload data from the UPF 514 is routed via the source infrastructure equipment 504 to the other potential target infrastructure equipment 511. In step 8, the target infrastructure equipment 506 determines that the handover of the communication device 502 from the source cell provided by the source infrastructure equipment 504 to the target cell provided by the target infrastructure equipment 506 was successful. In response, in step 8a, the target infrastructure equipment 506 transmits a handover success message to the source infrastructure equipment 504.In step 8b, the source infrastructure equipment 504 transmits an SN status transmission message to the destination infrastructure equipment 506. Subsequent payload data from the UPF 514 to the source infrastructure equipment is routed to the destination infrastructure equipment 506. In step 8c, a handover abort message is transmitted from the source infrastructure equipment 504 to the destination infrastructure equipment and the further potential destination infrastructure equipment 511.

[0031] As above in step 6 of Fig. As mentioned in section 4, the source infrastructure equipment 504 can transmit a configuration message for a conditional handover to the communication device 502, which has one or more conditions to trigger the handover.

[0032] An example of a condition that must be met to trigger a handover of the communication device 502 is "Event A3". The condition defined by Event A3 is met when the signal quality of a cell provided by an adjacent infrastructure device (for example, the destination infrastructure device 506 or the further potential destination infrastructure device 511) becomes a predefined offset higher than the signal quality of a cell provided by the source infrastructure device 504.

[0033] Another example of a condition that must be met to trigger a handover of the communication device 502 is "Event A4". The condition defined by Event A4 is met when the signal quality of the cell provided by the adjacent infrastructure equipment exceeds an absolute threshold.

[0034] Another example of a condition that must be met to trigger a handover of the communication device 502 is "Event A5". The condition defined by Event A5 is met when the signal quality of the cell provided by the source infrastructure equipment 504 is below an absolute threshold and the signal quality of the adjacent infrastructure equipment exceeds an absolute threshold.

[0035] The “signal quality” mentioned above in connection with the definitions of events A3, A4, and A5 can be measured by the communication device 502 using one or more signal quality parameters, such as RSRP, RSRQ, and SINR. For example, the communication device 502 can determine that the condition represented in event A3 may be met if a measured RSRP from the cell provided by the adjacent infrastructure equipment is one predefined offset higher than the measured RSRP for the cell provided by the source infrastructure equipment 504. In another example, the condition represented in event A3 may be determined to be met if a measured RSRP and RSRQ from the cell provided by the adjacent infrastructure equipment are each one predefined offset higher than the measured RSRP and RSRQ for the cell provided by the source infrastructure equipment 504.In Release 16 of the 3GPP group standards, only one reference signal type and the measurement of a maximum of two signal quality parameters are supported to determine whether events A3, A4 and / or A5 are fulfilled.

[0036] Each of the events A3, A4, and A5 therefore represents a condition for triggering a handover of the communication device 502 from the source infrastructure equipment 504. To trigger the handover, it may be sufficient for only one condition included in the configuration message for the conditional handover to be met, or triggering the handover may require that more than one or all conditions in the configuration message be met. In one example, only event A3 is included as a condition, and the handover is triggered when event A3 is met. In another example, both events A3 and A4 are included as conditions, and the handover is triggered when either event A3 or event A4 is met. In yet another example, both events A3 and A4 are included as conditions, and the handover is triggered when both events A3 and A4 are met.

[0037] Further details regarding events A3, A4 and A5 are described in TS 36.331, which is hereby incorporated in its entirety by reference. Network Energy Saving (NES)

[0038] In Release 18 of the 3GPP Standards, a new study object on Network Energy Saving (NES) ([4]) was initiated. The objectives of the study object are as follows: (i) Definition of an energy consumption model for base stations

[0039] Objective (i) is expected to involve the adaptation of power consumption modeling frameworks and evaluation methods for user terminal equipment (UTE) energy saving in NR (as discussed in [5]) by the base station. This is expected to include the adaptation of the relative power consumption for downlink (DL) and uplink (UL) (taking into account factors such as power amplifier (PA) efficiency, the number of TXRU interfaces, base station utilization, etc.), sleep states and their associated transition times, and one or more reference parameters / configurations. (ii) Definition of an evaluation methodology and key performance indicators (KPIs)

[0040] Objective (ii) is expected to focus the assessment methodology on evaluating network-wide energy consumption and energy savings, as well as assessing and weighing the impact on network and user performance (for example, spectral efficiency, capacity, user-perceived throughput (UPT), latency, handover performance, call drop rate, initial access performance, KPIs related to ensuring service level agreements (SLAs)), energy efficiency, user device power consumption, user environment (UE), and complexity. The assessment methodology is expected to focus on reusing existing KPIs whenever possible, rather than concentrating on a single KPI. If existing KPIs are found to be insufficient, new KPIs can be developed as needed. It is not yet determined which KPIs will be assessed and how this will be done. (iii) Identification of techniques on the part of the gNB and the UE to improve network energy savings with regard to the transmission and reception of the base station

[0041] The objective (iii) is expected to enable efficient dynamic and / or semi-static operation and finer granular adjustment of transmissions and / or receptions in one or more of the network-side energy-saving techniques in time, frequency, spatial, and power domains, with possible support or feedback from the user terminal equipment (UTE) and possible UTE assistance information. The objective (iii) is further expected to enable information exchange and coordination via network interfaces.

[0042] The study is expected to prioritize scenarios with idle / vacancy and low / medium utilization, allowing for varying utilization levels between network operators and neighboring cells. The precise definition of such loads will be determined within the scope of the study.

[0043] The following examples of single-carrier and multi-carrier deployments should be given priority in the study project: - Urban Micro in FR1, including time-duplex (TDD) with massive multiple-input multiple-output (MIMO). This can also model small cells. - FR2 beam-based scenarios (Note: This scenario can also model small cells) - Urban / rural macrocells in FR1 with or without Dynamic Spectrum Sharing (DSS). In the case of Dynamic Spectrum Sharing (DSS), no impact on LTE is expected. - Evolved Universal Terrestrial Radio Access - New Radio Dual Connectivity (EN-DC) / New Radio Dual Connectivity (NR-DC) Macrocell with Frequency Duplex (FDD) Primary Cell (PCell) and TDD / Massive MIMO (Multiple-Input Multiple-Output) on higher FR1 / FR2 frequency ranges.

[0044] It is intended that existing user end devices (UEs) will continue to be able to access a network that implements Release 18 network energy-saving techniques, with the possible exception of techniques specifically designed for new installations (“greenfield” deployments). Network Energy Saving Modes (NES)

[0045] It has been proposed that cells provided by infrastructure equipment of a wireless communications network be configured to operate according to the NES modes. Table 1 (adapted from [6]) shows examples of proposed NES modes. Table 1. Suggested NES modes. NES mode Characteristics Relative Power P Additional transition energy E Total transition periodT Deep sleep Neither DL transmission nor UL reception takes place. The time interval for sleep is longer than the entire transition time to enter and exit this state. P1 E1 T1 Light sleep Neither DL transmission nor UL reception takes place. The time interval for sleep is longer than the entire transition time to enter and exit this state. P2 E2 T2 Microsleep Neither DL transmission nor UL reception takes place. For study purposes regarding network energy saving, an immediate transition to or from a non-sleep state is assumed. P3 0 0 Active DL Only a DL transmission will take place. P4 Not applicable (N / A) Active UL Only ultralight (UL) receptions will take place.

[0046] In Table 1, the transition time, T, for an NES mode denotes the time a cell requires to enter or exit that NES mode. The additional transition energy, E, for an NES mode is the energy a cell requires relative to a reference energy to enter or exit that NES mode. The relative power, P, of an NES mode is the power consumed entering or exiting that NES mode relative to a reference power.

[0047] As experts in this field understand, the relative power for deep sleep NES mode is lower than the relative power for light sleep NES mode, which in turn is lower than the relative power for microsleep NES mode. In other words: P1 < P2 < P3. Furthermore, as experts in this field understand, the relative power of active UL NES mode is lower than that of active DL NES mode. In other words: P5 < P4.

[0048] Table 2 (taken from [6]) shows examples of the relative power values, P, of the NES modes shown in Table 1 for different categories of base stations and reference configuration sets. Further details on the base station categories and reference configuration sets can be found in [6]. Table 2. Relative performance of the proposed NES modes. NES mode BS Category 1 BS Category 2 Sentence 1 Sentence 2 Sentence 3 Sentence 1 Sentence 2 Sentence 3 Deep sleep 1 1 Light sleep 25 2,1 Microsleep 55 50 38 5,5 5 3 Active DL 280 200 152 32 26 17,6 Active UL 110 90 80 6,5 5,8 4,2

[0049] In addition to the NES modes proposed in Table 1, other NES modes are considered. For example, a cell may be configured to operate according to an NES mode that has a relative power output lower than that of the deep sleep NES mode and requires a longer transition time. This may be referred to as a "hibernation" or "quasi-off" NES mode. Another example of an NES mode is the "OFF" NES mode, in which the cell is switched off for uplink and downlink data transmissions. As understood by experts, a communications device in a cell operating in "OFF" NES mode may still receive reference signals or send wake-up signals to activate the cell.

[0050] Configuring network nodes to operate according to NES modes is expected to improve network energy savings. For example, according to a network planning strategy, different cells in a wireless communication network can operate according to different NES modes. For instance, one cell can be configured in micro-sleep NES mode if short-term uplink or downlink traffic is expected, and another cell can be configured in deep sleep NES mode if no uplink or downlink traffic is expected for an extended period.

[0051] Improvements to conditional handover in the context of NES have been discussed in [6] and [7], which are hereby incorporated in full by reference. In particular, it has been proposed to improve conditional handover by making the evaluation of the conditional handover conditions dependent on the NES mode of the source and destination cells. However, in existing conditional handover procedures, communication devices periodically or continuously evaluate the handover conditions, which can lead to energy waste. Furthermore, communication devices may not be aware of changes or anticipated changes in the NES modes of cells in the wireless communication network. Therefore, communication devices may remain in cells with NES modes unsuitable for the respective communication device for too long, resulting in further energy loss.For example, a communication device might be located in a cell that has just activated an NES mode, but the communication device can only be moved to another cell after the conditions for a handover have been evaluated. Therefore, improving the energy efficiency of conditional handovers presents technical challenges.

[0052] Therefore, there is a need for communication devices, infrastructure equipment, and methods to improve the energy efficiency of conditional handover in wireless communication networks.

[0053] A method for operating source infrastructure equipment of a wireless communication network in a conditional handover according to exemplary embodiments is described in Fig. 5 is shown. The procedure begins in step S1.

[0054] Following step S1, the procedure in step S2 includes configuring one or more conditions to trigger a handover of a communication device from a source cell provided by the source infrastructure equipment to a destination cell provided by a destination infrastructure equipment of the wireless communication network.

[0055] One or more conditions can be explicitly or implicitly based on an NES mode of the source and / or target cell. An example of an explicit condition based on the target cell's NES mode is that the communication device switches to a target cell when the target cell is configured to operate in a light sleep or microsleep NES mode. An example of an implicit condition based on the target cell's NES mode is that the communication device switches to the target cell when the target cell's Reference Signal Received Power (RSRP), as detected by the communication device, exceeds a predefined threshold.In this example, the target cell may be configured to operate in a deep sleep NES mode, and the source infrastructure equipment may configure the RSRP threshold relatively high because the target cell is in deep sleep NES mode. Similarly, the source infrastructure equipment may configure the RSRP threshold relatively low (i.e., lower than if the target cell were configured to operate in a deep sleep NES mode) if the target cell is configured to operate in a light sleep NES mode. Further examples of conditions that trigger the handover are discussed in the "Example Handover Conditions" section below.

[0056] Following step S2, the procedure in step S3 includes transmitting to the communication device a message indicating one or more conditions for triggering the handover of the communication device from the source cell to the destination cell. For example, the source infrastructure equipment can transmit a configuration message for a conditional handover (as in step 6 of Fig. (described in section 4), which includes one or more conditions for triggering the handover. The configuration message for the conditional handover can, for example, be transmitted as an RRC signal.

[0057] Following step S3, the procedure in step S4 includes determining that a network energy saving mode, NES, has changed or is expected to change by the source cell and / or the destination cell.

[0058] It is understood that a “change in NES mode” of a cell includes switching the cell from one NES mode to another (such as the NES modes shown in Table 1), switching from a non-operational state according to an NES mode (“NES MODE OFF”) to an operational state according to an NES mode (“NES MODE ON”), or switching from an operational state according to an NES mode (“NES MODE ON”) to a non-operational state according to an NES mode (“NES MODE OFF”). An example of a “NES MODE OFF” state is when a cell is “ON” and not operating according to an NES mode. An example of a “NES MODE ON” state is when a cell is in NES mode, in which the cell is disabled for uplink and downlink data transmissions. Another example of a “NES MODE ON” state is when the cell is operating according to one of the NES modes shown in Table 1.

[0059] The source infrastructure equipment can determine that the NES mode of the source cell has changed or is expected to change, or determine that the NES mode of the destination cell has changed or is expected to change, or determine that the NES mode of both the source cell and the destination cell has changed or is expected to change.

[0060] In some embodiments, the source infrastructure equipment can determine that the NES mode of the source cell and / or the destination cell has already changed. For example, the source infrastructure equipment can determine that the NES mode of the source cell has changed. In some embodiments, the source infrastructure equipment can determine that the NES mode of the destination cell has changed based on an indication received from the destination infrastructure equipment (for example, via an Xn interface). In some embodiments, the source infrastructure equipment can determine that the NES mode of the destination cell has changed because it receives an indication from the destination infrastructure equipment that the destination cell has switched from operating in an NES MODE OFF state to operating in an NES MODE ON state.

[0061] In some embodiments, the source infrastructure equipment can determine that the NES mode of the source cell and / or the destination cell is expected to change (i.e., at a later time). For example, the source infrastructure equipment can determine to change the NES mode of the source cell and, in response to this determination, transmit the evaluation trigger signal. In another example, the source infrastructure equipment can determine, based on an indication received from the destination infrastructure equipment that the NES mode of the destination cell is expected to change, that the NES mode of the destination cell is expected to change. For example, the destination infrastructure equipment can determine to change the NES mode of the destination cell and transmit an indication that the NES mode of the destination cell is about to change to the source infrastructure equipment.In one example, the source infrastructure equipment can determine that the NES mode of the destination cell is likely to change because it receives an indication from the destination infrastructure equipment that the destination cell is about to switch from operating in an NES MODE OFF state to operating in an NES MODE ON state.

[0062] Following step S4, the procedure in step S5 involves transmitting the evaluation trigger signal to the communication device. The evaluation trigger signal indicates to the communication device that it should evaluate one or more of the conditions for triggering the handover of the communication device from the source cell to the target cell.

[0063] In some embodiments, the evaluation trigger signal specifically indicates one or more of the conditions to be evaluated by the communication device. For example, the evaluation trigger signal can indicate to the communication device that it is to evaluate a subset of the conditions transmitted to it from the source infrastructure equipment in step S3. Thus, in step S3, the one or more conditions received from the source infrastructure equipment may comprise a multitude of conditions, each labeled with "Index 1" and "Index 2." Then, in step S5, the evaluation trigger signal can indicate that the condition with Index 1 is to be evaluated by the communication device. In other examples, the evaluation trigger signal indicates that the communication device is to evaluate all conditions transmitted from the source infrastructure equipment in step S3.

[0064] In some embodiments, the evaluation trigger signal may include an indication of the NES mode of the source cell and / or the target cell. For example, one of the conditions may be that the communication device switches to the target cell when the target cell is in light sleep NES mode. In this example, the evaluation trigger signal, which tells the communication device to evaluate the condition, also indicates to the communication device that the NES mode of the target cell has changed or is about to change to light sleep NES mode.

[0065] In some embodiments, the destination infrastructure equipment determines that the NES mode of the destination cell has changed or is about to change and transmits a notification to the source infrastructure equipment to transmit the evaluation trigger signal to the communication device. Therefore, the source infrastructure equipment determines, based on the notification to transmit the evaluation trigger signal, that the NES mode of the destination cell is likely to change. In this case, the determination is implicit, since the notification to transmit the evaluation trigger signal may not contain an explicit indication that the destination cell has changed or is about to change. In some embodiments, the notification to transmit the evaluation trigger signal to the communication device is transmitted via an Xn interface between the source infrastructure equipment and the destination infrastructure equipment.In such embodiments, the target infrastructure equipment effectively triggers the evaluation of one or more conditions by the communication device. For example, the target infrastructure equipment can determine that the NES mode of the target cell has changed because the target cell has transitioned from operating in an NES-MODE-ON state to an NES-MODE-OFF state. For instance, the target cell may have been woken up by a communication device within the target cell by transmitting a wake-up signal to the target infrastructure equipment. Therefore, when the target cell transitions to an NES-MODE-ON state, the target infrastructure equipment can effectively initiate the handover of the communication device to the target cell.

[0066] In some embodiments, the source infrastructure equipment can transmit handover support information to the destination infrastructure equipment. Based on a change or anticipated change in the destination cell's NES mode and the handover support information, the destination infrastructure equipment can determine to send an indication to transmit the evaluation trigger signal to the source infrastructure equipment. In response, the destination infrastructure equipment can then transmit the evaluation trigger signal to the source infrastructure equipment. The handover support information can include one or more of the following: a number of communication devices in the source cell as candidates for handover to the destination cell, a quality of service required by the communication devices, a service required by the communication devices, and a traffic volume required by the communication devices.

[0067] In some embodiments, the evaluation trigger signal is a radio resource control (RRC) signal associated with the communication device. In other embodiments, the evaluation trigger signal is a group transmission RRC signal for reception by multiple communication devices in the source cell. In this case, the group transmission RRC signal includes a group-wide, GC, temporary radio network identifier (RNTI) for identifying the multiple communication devices in the source cell.

[0068] In some embodiments, the evaluation trigger signal is a media access control (MAC) signal associated with the communication device. In some embodiments, the evaluation trigger signal is a group transmission MAC signal for reception by multiple communication devices in the source cell. In this case, the group transmission MAC signal includes a group-shared temporary radio network identifier, GC-RNTI, for identifying the multiple communication devices in the source cell.

[0069] In some embodiments, the evaluation trigger signal is a media access control MAC, control element CE, signal.

[0070] In some embodiments, the evaluation trigger signal is a broadcast signal for reception by a plurality of communication devices in the source cell.

[0071] In some embodiments, the evaluation trigger signal is included in group-shared downlink control information (DCI) for reception by a plurality of communication devices in the source cell, wherein the group-shared DCI includes a group-shared temporary radio network identifier (GC-RNTI) for identifying the plurality of communication devices in the source cell.

[0072] The procedure ends in step S6.

[0073] A method for operating a communication device in a conditional handover according to exemplary embodiments is described in Fig. Figure 6. The procedure begins in step S11.

[0074] Following step S11, the procedure in step S12 includes receiving one or more conditions to trigger a handover of the communication device from a source cell provided by the source infrastructure equipment to a destination cell provided by a destination infrastructure of the wireless communication network.

[0075] Following step S12, the procedure in step S13 includes receiving an evaluation trigger signal from the source infrastructure equipment, which indicates to the communication device to evaluate one or more of the conditions for triggering the handover of the communication device from the source cell to the destination cell. The evaluation trigger signal is received by the communication device from the source infrastructure equipment in response to a change or anticipated change in a network energy saving mode (NES) of the source cell and / or the destination cell.

[0076] Following step S13, the procedure in step S14 includes, in response, evaluating one or more conditions to trigger the handover of the communication device from the source cell to the target cell.

[0077] Following step S14, the procedure in step S15 includes determining that one or more of the evaluated conditions are met.

[0078] Following step S15, the procedure in step S16 includes, in response, initiating the handover of the communication device from the source cell to the target cell.

[0079] Initiating a handover can involve disconnecting from a wireless access interface or radio link provided by the source infrastructure equipment and connecting to a wireless access interface or radio link provided by the destination infrastructure equipment. Initiating a handover can include establishing a wireless connection with the destination relay infrastructure equipment. For example, the communication device can initiate an access procedure with the destination infrastructure equipment. In one example, the communication device can initiate a Random Access Channel (RACH) procedure with the destination infrastructure equipment.

[0080] The procedure ends in step S17.

[0081] As above regarding the Fig. 5 and Fig.As described in Figure 6, the source infrastructure equipment transmits the evaluation trigger signal to the communication device, which then evaluates one or more conditions. The communication device subsequently determines that the condition is satisfied and initiates the handover. Therefore, the embodiments allow the wireless communication network, which is aware of changes or expected changes in the NES modes, to control when the communication device evaluates the conditions. Since the communication device evaluates one or more conditions in response to receiving the evaluation trigger signal (rather than the periodic or continuous evaluation typical of a conventional conditional handover), it is expected that before reaching a positive evaluation result (i.e.,(based on the determination that one or more conditions are met) fewer evaluations are performed, thereby reducing energy consumption in the wireless communication network. Furthermore, transmitting the evaluation trigger signal in response to the determination that the NES mode has changed or is expected to change in the source and / or destination cell means that communication devices are able to switch cells (or remain in a cell) in response to changes or expected changes in NES modes. The wireless communication network can efficiently control which communication devices are located in which cells based on changes in NES modes, for example, according to a network planning strategy. Evaluation stop signal

[0082] In some embodiments, the evaluation trigger signal is transmitted from the source infrastructure equipment to the communication device to indicate to the communication device to evaluate one or more conditions, and a second, subsequent signal (hereinafter referred to as the "evaluation stop signal") is transmitted from the source infrastructure equipment to the communication device to indicate to the communication device to stop evaluating the one or more conditions.

[0083] In some embodiments, the source infrastructure equipment can transmit the evaluation stop signal to the communication device in response to a further change in the NES mode of the source and / or destination cell. For example, the source infrastructure equipment can transmit the evaluation trigger signal to the communication device after it has been determined that the destination cell has changed from the "NES MODE ON" state to the "NES MODE OFF" state. In response, upon a subsequent determination that the destination cell has changed from the "NES MODE OFF" state to the "NES MODE ON" state, the source infrastructure equipment can transmit the evaluation stop signal to the communication device.

[0084] References to the fact that the evaluation stop signal is transmitted in response to a "further change in NES mode from the source and / or target cell" include cases in which: - the evaluation trigger signal is transmitted in response to a change or expected change in the NES mode of the source cell, and the evaluation stop signal is transmitted in response to a change or expected change in the NES mode of the source cell. - the evaluation trigger signal is transmitted in response to a change or expected change in the NES mode of the target cell, and the evaluation stop signal is transmitted in response to a change or expected change in the NES mode of the target cell. - the evaluation trigger signal is transmitted in response to a change or expected change in the NES mode of the source cell, and the evaluation stop signal is transmitted in response to a change or expected change in the NES mode of the target cell, and - the evaluation trigger signal is transmitted in response to a change or expected change in the NES mode of the target cell, and the evaluation stop signal is transmitted in response to a change or expected change in the NES mode of the source cell.

[0085] In some embodiments, the evaluation stop signal can be transmitted based on the sequence of a pre-configured timer.

[0086] Therefore, the evaluation trigger signal and the evaluation stop signal can each be used to activate or deactivate the evaluation of one or more conditions. In some embodiments, one or both signals, the evaluation trigger signal and the evaluation stop signal, can be transmitted as MAC-CE. Since the MAC layer is closer to the physical layer than higher layers, such as the RRC layer, the use of a MAC-CE enables fast transmission, allowing the evaluation trigger signal and the evaluation stop signal to quickly activate and deactivate the evaluation of one or more conditions. Evaluation restart signal

[0087] In some embodiments, a further signal (hereinafter referred to as the "evaluation restart signal") following the evaluation stop signal is transmitted from the source infrastructure equipment to the communication device to indicate to the communication device to restart the evaluation of one or more conditions.

[0088] In some embodiments, the source infrastructure equipment can transmit the evaluation restart signal to the communication device in response to a further change in the NES mode from the source and / or the destination cell. For example, the source infrastructure equipment can transmit the evaluation stop signal to the communication device after it has been determined that the destination cell has changed from the "NES MODE OFF" state to the "NES MODE ON" state. Then, upon a subsequent determination that the destination cell has changed from the "NES MODE ON" state to the "NES MODE OFF" state, the source infrastructure equipment can transmit the evaluation restart signal to the communication device.

[0089] References to the fact that the evaluation restart signal is transmitted in response to a "further change in NES mode from the source and / or target cell" indicate cases in which: - the evaluation stop signal is transmitted in response to a change or expected change in the NES mode of the source cell, and the evaluation restart signal is transmitted in response to a change or expected change in the NES mode of the source cell, - the evaluation stop signal is transmitted in response to a change or expected change in the NES mode of the target cell, and the evaluation restart signal is transmitted in response to a change or expected change in the NES mode of the target cell, - the evaluation stop signal is transmitted in response to a change or expected change in the NES mode of the source cell, and the evaluation restart signal is transmitted in response to a change or expected change in the NES mode of the target cell, and - the evaluation stop signal is transmitted in response to a change or expected change in the NES mode of the target cell, and the evaluation restart signal is transmitted in response to a change or expected change in the NES mode of the source cell.

[0090] In some embodiments, the evaluation restart signal can be transmitted based on the sequence of a pre-configured timer.

[0091] Therefore, the evaluation restart signal can be used to reactivate the evaluation of one or more conditions. In some embodiments, the evaluation restart signal can be transmitted as MAC-CE. Since the MAC layer is closer to the physical layer than higher layers such as the RRC layer, the use of a MAC-CE enables fast transmission, and the evaluation restart signal allows for rapid reactivation of the evaluation of one or more conditions.

[0092] In one example, a wireless communication network can comprise a plurality of candidate target cells (for example, three candidate target cells). The candidate target cells can be provided by the same or different target infrastructure equipment. A source infrastructure piece of equipment can configure a communication device in a source cell provided by the source infrastructure equipment with configurations for each of the plurality of candidate target cells. For example, the communication device can be configured with settings such as measurements and / or conditions for handover to each of the plurality of candidate target cells.

[0093] In conventional conditional handover, the communication device can evaluate the handover conditions for each of the plurality of candidate target cells and switch to the candidate target cell for which a handover condition is met (for example, because a threshold for an event has been reached).

[0094] According to exemplary embodiments, the communication device may or may not evaluate the handover conditions for candidate target cells based on the NES mode of each candidate target cell. For example, the first and second of a plurality of candidate target cells may not be in NES mode, while a third of the plurality of target cells may be in NES mode (for example, the third target cell may be switched off). According to exemplary embodiments, the communication device may evaluate the conditions for a handover to the first and second target cells. However, the communication device may also determine that the conditions for a handover to the first and second target cells are not met. In some cases, the communication device continuously evaluates the handover conditions for the first and second target cells.This evaluation can continue for a certain period of time if the handover conditions are not met. At a later time, the NES mode of the third target cell may change. For example, the third target cell may be powered on. According to exemplary embodiments, the source infrastructure equipment can determine that the NES mode of the third target cell has changed and, in response, transmit a signal to the communication device indicating that it is evaluating the conditions for a handover to the third target cell. The communication device can then evaluate the conditions for a handover to the first target cell, the second target cell, and the third target cell. The communication device switches to the target cell for which a handover condition is met first.Therefore, in some examples, the communication device can switch to the second target cell, in other examples to the first target cell, and in still others to the third target cell, using a handover. In some examples, the communication device evaluates the conditions for the handover to the third target cell instead of evaluating the conditions for the handover to the first and second target cells, because the information required to evaluate the conditions for the third target cell was received later. Example conditions for the handover

[0095] As explained above, the source infrastructure equipment configures one or more conditions for the communication device, which, when met, cause the communication device to hand over from the source cell to the destination cell. Further examples of such conditions are listed below: - If the source cell has changed, or is expected to change, to an NES-MODE-ON state (for example, to a deep sleep NES mode or a state where the cell is powered off), the communication device will switch from the source cell to the destination cell. For example, the source infrastructure equipment can transmit the evaluation trigger signal to the communication device after determining that the source cell's NES mode has changed. In this way, the source infrastructure equipment can promote network energy conservation by switching to an NES-MODE-ON state and thus offloading its communication devices to the destination cell. - If the target cell has changed, or is expected to change, to an NES-MODE OFF state or a low-power NES mode (for example, to a relatively high-power NES mode such as the light sleep NES mode), the communication device will switch from the source cell to the target cell. In one example, the source infrastructure equipment can transmit the evaluation trigger signal to the communication device after determining that the target cell's NES mode has changed. This allows the target infrastructure equipment to accommodate new communication devices when it transitions to an NES-MODE OFF state or a low-power NES mode. - If the source cell has changed, or is expected to change, to an NES-MODE-OFF state (or to a low-power NES mode, such as a relatively high-power NES mode like the light sleep NES mode), the communication device switches from the source cell to the destination cell. In one example, the source infrastructure equipment can transmit the evaluation trigger signal to the communication device after determining that the source cell's NES mode has changed. In this example, a communication device that preferably operates in an NES-MODE-ON state can be migrated to the destination cell to promote energy savings. - If the target cell has changed, or is expected to change, to an NES-MODE-ON state (for example, to a deep sleep NES mode), the communication device switches from the source cell to the target cell via handover. In one example, the source infrastructure equipment can transmit the evaluation trigger signal to the communication device after determining that the target cell's NES mode has changed. This allows the target infrastructure equipment to accommodate new communication devices, which preferably operate in an NES-MODE-ON state to promote energy savings.

[0096] It is acknowledged that, although the present disclosure has focused in some aspects on implementations in an LTE-based and / or 5G network to clarify specific examples, the same principles can be applied to other wireless telecommunications systems. While the terminology used herein generally corresponds to or resembles that of the LTE and 5G standards, the teachings are not limited to current versions of LTE and 5G but can be applied equally to any suitable arrangement that is not based on LTE or 5G and / or conforms to future versions of an LTE, 5G, or other standard.

[0097] It should be noted that several exemplary approaches discussed here may rely on information that is predetermined or predefined in terms of both the base station and the communication device. It is understood that such predetermined or predefined information may generally be defined, for example, in an operating standard for the wireless telecommunications system, through previously exchanged signaling between the base station and the communication devices (for example, in system information signaling), in connection with the setup of the radio resource control, or in information stored in a SIM application.This means that the specific way in which the relevant predefined information is established and shared between the various elements of the wireless telecommunications system is not of primary importance for the operating principles described here. It should also be noted that several example approaches discussed here rely on information being exchanged or transmitted between different elements of the wireless telecommunications system, and it is understood that such communication processes can generally be carried out according to conventional procedures, for example, with regard to specific signaling protocols and the type of communication channel used, unless the context requires otherwise.This means that the specific way in which the relevant information is exchanged between the different elements of the wireless telecommunications system is not of primary importance for the operating principles described here.

[0098] It is understood that the principles described here are not only applicable to specific types of communication devices, but can be applied generally to any type of communication device. For example, the approaches are not limited to URLLC / IIoT devices or other low-latency communication devices, but can be applied generally to any type of communication device that operates with a wireless connection to the communication network.

[0099] It is further understood that the principles described here are not only applicable to LTE-based or 5G / NR-based wireless telecommunications systems, but to any type of wireless telecommunications system that supports dynamic planning of shared communication resources.

[0100] Further specific and preferred aspects of the present invention are set out in the accompanying independent and dependent claims. It is understood that features of the dependent claims may be combined with features of the independent claims in combinations other than those expressly set out in the claims.

[0101] Therefore, the foregoing discussion discloses and describes only exemplary embodiments of the present invention. As a person skilled in the art understands, the present invention can be implemented in other specific forms without deviating from its idea or essential characteristics. Accordingly, the disclosure of the present invention is to be regarded as exemplary and is not intended to limit the scope of the invention or of other claims. The disclosure, including any readily recognizable variations of the present teachings, partially defines the scope of protection of the foregoing claim terminology in such a way that no subject matter of the invention is intended for public disclosure.

[0102] The respective features of the present disclosure are defined by the following numbered paragraphs: Paragraph 1. A method for operating source infrastructure equipment of a wireless communications network in a conditional handover, the method comprising: Configuring one or more conditions to trigger a handover of a communication device from a source cell provided by the source infrastructure equipment to a destination cell provided by destination infrastructure equipment of the wireless communication network,

[0103] Transmitted to the communication device, an indication of one or more conditions for triggering the handover of the communication device from the source cell to the destination cell,

[0104] Determine that a network energy saving mode (NES) has changed or is expected to change by the source cell and / or the destination cell, and, in response,

[0105] A communication device transmits an evaluation trigger signal, wherein the evaluation trigger signal indicates to the communication device to evaluate one or more of the conditions for triggering the handover of the communication device from the source cell to the target cell.

[0106] Paragraph 2. A procedure under paragraph 1 comprising the following: Transmitting an evaluation stop signal that indicates to the communication device to stop evaluating one or more conditions to trigger the handover of the communication device from the source cell to the target cell.

[0107] Paragraph 3. A procedure according to paragraph 2, comprising the following: Transmitting an evaluation restart signal that indicates to the communication device to re-evaluate the one or more conditions for triggering the handover of the communication device from the source cell to the target cell.

[0108] Paragraph 4. A method according to paragraph 3, wherein one or more of the evaluation trigger signal, the evaluation stop signal and the evaluation restart signal are transmitted in a media access control, MAC, control element, CE.

[0109] Paragraph 5. A method according to any of paragraphs 1 to 4, wherein the evaluation trigger signal includes an indication of the NES mode from the source cell and / or the target cell.

[0110] Paragraph 6. A method according to any of paragraphs 1 to 4, wherein the evaluation trigger signal is a radio resource control (RRC) signal belonging to the communication device.

[0111] Paragraph 7. A method according to any of paragraphs 1 to 4, wherein the evaluation trigger signal is a group transmission radio resource control (RRC) signal for reception by a plurality of communication devices in the source cell, wherein the group transmission RRC signal comprises a group common (GC) temporary radio network identifier (RNTI) for identifying the plurality of communication devices in the source cell.

[0112] Paragraph 8. A method according to any of paragraphs 1 to 4, wherein the evaluation trigger signal is a media access control (MAC) signal belonging to the communication device.

[0113] Paragraph 9. A method according to any of paragraphs 1 to 4, wherein the evaluation trigger signal is a group transmission media access control (MAC) signal for reception by a plurality of communication devices in the source cell, wherein the group transmission MAC signal includes a group common (GC) temporary radio network identifier (RNTI) for identifying the plurality of communication devices in the source cell.

[0114] Paragraph 10. A method according to any of paragraphs 1 to 4, wherein the evaluation trigger signal is a broadcast signal for reception by a plurality of communication devices in the source cell.

[0115] Paragraph 11. A method according to any of paragraphs 1 to 4, wherein the evaluation trigger signal is contained in a group-shared downlink control information, DCI, for reception by a plurality of communication devices in the source cell, wherein the group-shared DCI comprises a group-shared, GC, temporary radio network identifier, RNTI, for identifying the plurality of communication devices in the source cell.

[0116] Paragraph 12. A procedure according to any of paragraphs 1 to 11, wherein determining that the NES mode has changed or is expected to change from the source cell and / or the target cell comprises the following: Received from the target infrastructure equipment, an indication that the NES mode of the target cell has changed or is expected to change.

[0117] Paragraph 13. A method according to paragraph 12, wherein the indication that the NES mode of the target infrastructure equipment has changed is transmitted via an Xn interface between the source infrastructure equipment and the target infrastructure equipment.

[0118] Paragraph 14. A procedure according to any of paragraphs 1 to 11, wherein determining that the NES mode has changed or is expected to change from the source cell and / or the target cell comprises the following: Receiving, from the target infrastructure equipment, an indication to transmit the evaluation trigger signal to the communication device in response to a change or anticipated change in the NES mode of the target cell.

[0119] Paragraph 15. A procedure under paragraph 14 comprising the following: Transferred to the destination infrastructure equipment, handover support information includes one or more of a number of communication devices in the source cell as candidates for handover to the destination cell, a quality of service required by the communication devices, a service required by the communication devices, and a traffic volume required by the communication devices.

[0120] Paragraph 16. A method for operating a communication device in a conditional handover, the method comprising: Receiving, from a source infrastructure equipment of a wireless communications network, an indication of one or more conditions to trigger a handover of the communication device from a source cell provided by the source infrastructure equipment to a destination cell provided by a destination infrastructure of the wireless communications network,

[0121] Receiving, from the source infrastructure equipment, an evaluation trigger signal indicating to the communication device to evaluate one or more of the conditions for triggering the handover of the communication device from the source cell to the destination cell, wherein the evaluation trigger signal from the source infrastructure equipment is received by the communication device in response to a change or anticipated change of a network energy saving mode (NES) of the source cell and / or the destination cell, and, in response thereto,

[0122] Evaluating one or more of the conditions for triggering the handover of the communication device from the source cell to the target cell,

[0123] Determine that one or more of the evaluated conditions are met, and, in response,

[0124] Initiating the handover of the communication device from the source cell to the destination cell. Paragraph 17. A method according to paragraph 16, comprising the following: Receiving an evaluation stop signal indicating to the communication device to stop evaluating one or more conditions to trigger the handover of the communication device from the source cell to the destination cell.

[0125] Paragraph 18. A procedure under paragraph 16 comprising the following: Receiving an evaluation restart signal that indicates to the communication device to re-evaluate the evaluation of one or more conditions for triggering the handover of the communication device from the source cell to the target cell.

[0126] Paragraph 19. A method according to paragraph 18, wherein one or more of the evaluation trigger signal, the evaluation stop signal and the evaluation restart signal are received in a media access control, MAC, control element, CE.

[0127] Paragraph 20. A method according to any of paragraphs 16 to 19, wherein the evaluation trigger signal includes an indication of the NES mode from the source cell and / or the target cell.

[0128] Paragraph 21. A method according to any of paragraphs 16 to 20, wherein the evaluation trigger signal is a radio resource control (RRC) signal belonging to the communication device.

[0129] Paragraph 22. A method according to any of paragraphs 16 to 20, wherein the evaluation trigger signal is a group transmission radio resource control (RRC) signal for reception by a plurality of communication devices in the source cell, wherein the group transmission RRC signal comprises a group common (GC) temporary radio network identifier (RNTI) for identifying the plurality of communication devices in the source cell.

[0130] Paragraph 23. A method according to any of paragraphs 16 to 20, wherein the evaluation trigger signal is a media access control (MAC) signal belonging to the communication device.

[0131] Paragraph 24. A method according to any of paragraphs 16 to 20, wherein the evaluation trigger signal is a group transmission media access control (MAC) signal for reception by a plurality of communication devices in the source cell, wherein the group transmission MAC signal includes a group common (GC) temporary radio network identifier (RNTI) for identifying the plurality of communication devices in the source cell.

[0132] Paragraph 25. A method according to any of paragraphs 16 to 20, wherein the evaluation trigger signal is a broadcast signal for reception by a plurality of communication devices in the source cell.

[0133] Paragraph 26. A method according to any of paragraphs 16 to 20, wherein the evaluation trigger signal is contained in a group-shared downlink control information, DCI, for reception by a plurality of communication devices in the source cell, wherein the group-shared DCI comprises a group-shared, GC, temporary radio network identifier, RNTI, for identifying the plurality of communication devices in the source cell.

[0134] Paragraph 27. Source infrastructure equipment of a wireless communications network for use in a conditional handover, wherein the source infrastructure equipment comprises the following: a transmitter configured to transmit signals; a receiver configured to receive signals; a controller which, in combination with the transmitter and the receiver, is configured to: Configuring one or more conditions to trigger a handover of a communication device from a source cell provided by the source infrastructure equipment to a destination cell provided by destination infrastructure equipment of the wireless communication network,

[0135] Transmitted to the communication device, an indication of one or more conditions for triggering the handover of the communication device from the source cell to the destination cell,

[0136] Determine that a network energy saving mode (NES) has changed or is expected to change by the source cell and / or the destination cell, and, in response,

[0137] Transmitting an evaluation trigger signal to the communication device, wherein the evaluation trigger signal of the communication device indicates that one or more of the conditions for triggering the handover of the communication device from the source cell to the target cell are to be evaluated.

[0138] Paragraph 28. A communication device for use in a conditional handover, the communication device comprising the following: a transmitter configured to transmit signals; a receiver configured to receive signals; a controller which, in combination with the transmitter and the receiver, is configured to: Receiving, from a source infrastructure equipment of a wireless communications network, an indication of one or more conditions to trigger a handover of the communication device from a source cell provided by the source infrastructure equipment to a destination cell provided by a destination infrastructure of the wireless communications network,

[0139] Receiving, from the source infrastructure equipment, an evaluation trigger signal indicating to the communication device to evaluate one or more of the conditions for triggering the handover of the communication device from the source cell to the destination cell, wherein the evaluation trigger signal from the source infrastructure equipment is received by the communication device in response to a change or anticipated change of a network energy saving mode (NES) of the source cell and / or the destination cell, and, in response thereto,

[0140] Evaluating one or more of the conditions for triggering the handover of the communication device from the source cell to the target cell,

[0141] Determine that one or more of the evaluated conditions are met, and, in response,

[0142] Initiating the handover of the communication device from the source cell to the destination cell. Paragraph 29. Circuit for source infrastructure equipment of a wireless communication network for use in a conditional handover, the circuit comprising: a transmitting circuit configured to transmit signals; a receiving circuit configured to receive signals; a control circuit which, in combination with the transmitting circuit and the receiving circuit, is configured to: Configuring one or more conditions to trigger a handover of a communication device from a source cell provided by the source infrastructure equipment to a destination cell provided by destination infrastructure equipment of the wireless communication network,

[0143] Transmitted to the communication device, an indication of one or more conditions for triggering the handover of the communication device from the source cell to the destination cell,

[0144] Determine that a network energy saving mode (NES) has changed or is expected to change by the source cell and / or the destination cell, and, in response,

[0145] Transmitting an evaluation trigger signal to the communication device, wherein the evaluation trigger signal of the communication device indicates that one or more of the conditions for triggering the handover of the communication device from the source cell to the target cell are to be evaluated.

[0146] Paragraph 30. Circuit for a communication device for use in a conditional handover, the circuit comprising the following: a transmitting circuit configured to transmit signals; a receiving circuit configured to receive signals; a control circuit which, in combination with the transmitting circuit and the receiving circuit, is configured to: Receiving, from a source infrastructure equipment of a wireless communications network, an indication of one or more conditions to trigger a handover of the communication device from a source cell provided by the source infrastructure equipment to a destination cell provided by a destination infrastructure of the wireless communications network,

[0147] Receiving, from the source infrastructure equipment, an evaluation trigger signal indicating to the communication device to evaluate one or more of the conditions for triggering the handover of the communication device from the source cell to the destination cell, wherein the evaluation trigger signal from the source infrastructure equipment is received by the communication device in response to a change or anticipated change of a network energy saving mode (NES) of the source cell and / or the destination cell, and, in response thereto,

[0148] Evaluating one or more of the conditions for triggering the handover of the communication device from the source cell to the target cell,

[0149] Determine that one or more of the evaluated conditions are met, and, in response,

[0150] Initiating the handover of the communication device from the source cell to the destination cell. Paragraph 31. A wireless communication system comprising a communication device as defined in paragraph 27 and infrastructure equipment as defined in paragraph 28.

[0151] Paragraph 32. A computer program comprising instructions which, when loaded onto a computer, cause the computer to perform a procedure according to any one of paragraphs 1 to 26.

[0152] Paragraph 33. A non-transitory computer-readable storage medium that stores a computer program according to paragraph 32. References [1] RP-182090, “Revised SID: Study on NR Industrial Internet of Things (IoT),” 3GPP RAN#81. [2] Holma H. ​​and Toskala A., “LTE for UMTS OFDMA and SC-FDMA based radio access”, John Wiley and Sons, 2009. [3] TS38.300 V16.5.0, “NG and NR-RAN Overall Description”, Release 16. [4] RP-213554, “Study on network energy savings for NR”. [5] TR38.840, “Study on User Equipment (UE) power saving in NR”, Release 16. [6] TR38.864, “Study on network energy savings for NR,” Release 18. [7] R2-2213040, “Post RAN2#120 TP for TR 38.864,” Release 18. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Zitierte Nicht-Patentliteratur

[0000] Holma H. und Toskala A., „LTE for UMTS OFDMA and SC-FDMA based radio access“, John Wiley and Sons, 2009

[0152] TS38.300 V16.5.0, „NG and NR-RAN Overall Description“, Release 16

[0152] RP-213554, „Study on network energy savings for NR

[0152] TR38.840, „Study on User Equipment (UE) power saving in NR“, Release 16

[0152] TR38.864, „Study on network energy savings for NR“, Release 18

[0152] R2-2213040, „Post RAN2#120 TP for TR 38.864“, Release 18

[0152]

Claims

[1] Method for operating source infrastructure equipment of a wireless communications network in a conditional handover, the method comprising: Configuring one or more conditions to trigger a handover of a communication device from a source cell provided by the source infrastructure equipment to a destination cell provided by destination infrastructure equipment of the wireless communication network, Transmitted to the communication device, an indication of one or more conditions for triggering the handover of the communication device from the source cell to the destination cell, Determine that a network energy saving mode (NES) has changed or is expected to change by the source cell and / or the destination cell, and, in response, A communication device transmits an evaluation trigger signal, wherein the evaluation trigger signal indicates to the communication device to evaluate one or more of the conditions for triggering the handover of the communication device from the source cell to the target cell. [2] The method of claim 1, comprising: Transmitting an evaluation stop signal that indicates to the communication device to stop evaluating one or more conditions to trigger the handover of the communication device from the source cell to the target cell. [3] The method of claim 2, comprising the following: Transmitting an evaluation restart signal that indicates to the communication device to re-evaluate the one or more conditions to trigger the handover of the communication device from the source cell to the target cell. [4] Method according to claim 3, wherein one or more of the evaluation trigger signal, the evaluation stop signal and the evaluation restart signal are transmitted in a media access control, MAC, control element, CE. [5] Method according to claim 1, wherein the evaluation trigger signal comprises an indication of the NES mode from the source cell and / or the target cell. [6] Method according to claim 1, wherein the evaluation trigger signal is a radio resource control (RRC) signal associated with the communication device. [7] Method according to claim 1, wherein the evaluation trigger signal is a group transmission radio resource control (RRC) signal for reception by a plurality of communication devices in the source cell, wherein the group transmission RRC signal comprises a group-shared (GC) temporary radio network identifier (RNTI) for identifying the plurality of communication devices in the source cell. [8] Method according to claim 1, wherein the evaluation trigger signal is a media access control (MAC) signal belonging to the communication device. [9] Method according to claim 1, wherein the evaluation trigger signal is a group transmission media access control (MAC) signal for reception by a plurality of communication devices in the source cell, wherein the group transmission MAC signal comprises a group-shared (GC) temporary radio network identifier (RNTI) for identifying the plurality of communication devices in the source cell. [10] Method according to claim 1, wherein the evaluation trigger signal is a broadcast signal for reception by a plurality of communication devices in the source cell. [11] Method according to claim 1, wherein the evaluation trigger signal is contained in a group-shared downlink control information, DCI, for reception by a plurality of communication devices in the source cell, wherein the group-shared DCI comprises a group-shared, GC, temporary radio network identifier, RNTI, for identifying the plurality of communication devices in the source cell. [12] Method according to claim 1, wherein determining that the NES mode has changed or is expected to change from the source cell and / or the target cell comprises: Received from the target infrastructure equipment, an indication that the NES mode of the target cell has changed or is expected to change. [13] Method according to claim 12, wherein the indication that the NES mode of the target infrastructure equipment has changed is transmitted via an Xn interface between the source infrastructure equipment and the target infrastructure equipment. [14] Method according to claim 1, wherein determining that the NES mode has changed or is expected to change from the source cell and / or the target cell comprises: Receiving, from the target infrastructure equipment, an indication to transmit the evaluation trigger signal to the communication device in response to a change or anticipated change in the NES mode of the target cell. [15] The method of claim 14, comprising: Transferred to the destination infrastructure equipment, handover support information includes one or more of a number of communication devices in the source cell as candidates for handover to the destination cell, a quality of service required by the communication devices, a service required by the communication devices, and a traffic volume required by the communication devices. [16] Method for operating a communication device in a conditional handover, the method comprising: Receiving, from a source infrastructure equipment of a wireless communications network, an indication of one or more conditions to trigger a handover of the communication device from a source cell provided by the source infrastructure equipment to a destination cell provided by a destination infrastructure of the wireless communications network, Receiving, from the source infrastructure equipment, an evaluation trigger signal indicating to the communication device to evaluate one or more of the conditions for triggering the handover of the communication device from the source cell to the destination cell, wherein the evaluation trigger signal from the source infrastructure equipment is received by the communication device in response to a change or anticipated change of a network energy saving mode (NES) of the source cell and / or the destination cell, and, in response thereto, Evaluating one or more of the conditions for triggering the handover of the communication device from the source cell to the target cell, Determine that one or more of the evaluated conditions are met, and, in response, Initiating the handover of the communication device from the source cell to the target cell. [17] The method of claim 16, comprising: Receiving an evaluation stop signal indicating to the communication device to stop evaluating one or more conditions to trigger the handover of the communication device from the source cell to the destination cell. [18] The method of claim 16, comprising the following: Receiving an evaluation restart signal that indicates to the communication device to re-evaluate the evaluation of one or more conditions for triggering the handover of the communication device from the source cell to the target cell. [19] Method according to claim 18, wherein one or more of the evaluation trigger signal, the evaluation stop signal and the evaluation restart signal are received in a media access control, MAC, control element, CE. [20] Method according to claim 16, wherein the evaluation trigger signal comprises an indication of the NES mode from the source cell and / or the target cell. [21] Method according to claim 16, wherein the evaluation trigger signal is a radio resource control (RRC) signal associated with the communication device. [22] Method according to claim 16, wherein the evaluation trigger signal is a group transmission radio resource control (RRC) signal for reception by a plurality of communication devices in the source cell, wherein the group transmission RRC signal comprises a group common (GC) temporary radio network identifier (RNTI) for identifying the plurality of communication devices in the source cell. [23] Method according to claim 16, wherein the evaluation trigger signal is a media access control (MAC) signal belonging to the communication device. [24] Method according to claim 16, wherein the evaluation trigger signal is a group transmission media access control (MAC) signal for reception by a plurality of communication devices in the source cell, wherein the group transmission MAC signal comprises a group-shared (GC) temporary radio network identifier (RNTI) for identifying the plurality of communication devices in the source cell. [25] Method according to claim 16, wherein the evaluation trigger signal is a broadcast signal for reception by a plurality of communication devices in the source cell. [26] Method according to claim 16, wherein the evaluation trigger signal is contained in a group-shared downlink control information, DCI, for reception by a plurality of communication devices in the source cell, wherein the group-shared DCI comprises a group-shared, GC, temporary radio network identifier, RNTI, for identifying the plurality of communication devices in the source cell. [27] Source infrastructure equipment of a wireless communications network for use in a conditional handover, wherein the source infrastructure equipment comprises: a transmitter configured to transmit signals; a receiver configured to receive signals; a controller which, in combination with the transmitter and the receiver, is configured to: Configuring one or more conditions to trigger a handover of a communication device from a source cell provided by the source infrastructure equipment to a destination cell provided by destination infrastructure equipment of the wireless communication network, Transmitted to the communication device, an indication of one or more conditions for triggering the handover of the communication device from the source cell to the destination cell, Determine that a network energy saving mode (NES) has changed or is expected to change by the source cell and / or the destination cell, and, in response, Transmitting an evaluation trigger signal to the communication device, wherein the evaluation trigger signal of the communication device indicates that one or more of the conditions for triggering the handover of the communication device from the source cell to the target cell are to be evaluated. [28] Communication device for use in a conditional handover, the communication device comprising: a transmitter configured to transmit signals; a receiver configured to receive signals; a controller which, in combination with the transmitter and the receiver, is configured to: Receiving, from a source infrastructure equipment of a wireless communications network, an indication of one or more conditions to trigger a handover of the communication device from a source cell provided by the source infrastructure equipment to a destination cell provided by a destination infrastructure of the wireless communications network, Receiving, from the source infrastructure equipment, an evaluation trigger signal indicating to the communication device to evaluate one or more of the conditions for triggering the handover of the communication device from the source cell to the destination cell, wherein the evaluation trigger signal from the source infrastructure equipment is received by the communication device in response to a change or anticipated change of a network energy saving mode (NES) of the source cell and / or the destination cell, and, in response thereto, Evaluating one or more of the conditions for triggering the handover of the communication device from the source cell to the target cell, Determine that one or more of the evaluated conditions are met, and, in response, Initiating the handover of the communication device from the source cell to the target cell. [29] Circuit for source infrastructure equipment of a wireless communications network for use in a conditional handover, the circuit comprising: a transmitting circuit configured to transmit signals; a receiving circuit configured to receive signals; a control circuit which, in combination with the transmitting circuit and the receiving circuit, is configured to: Configuring one or more conditions to trigger a handover of a communication device from a source cell provided by the source infrastructure equipment to a destination cell provided by destination infrastructure equipment of the wireless communication network, Transmitted to the communication device, an indication of one or more conditions for triggering the handover of the communication device from the source cell to the destination cell, Determine that a network energy saving mode (NES) has changed or is expected to change by the source cell and / or the destination cell, and, in response, Transmitting an evaluation trigger signal to the communication device, wherein the evaluation trigger signal of the communication device indicates that one or more of the conditions for triggering the handover of the communication device from the source cell to the target cell are to be evaluated. [30] Circuit for a communication device for use in a conditional handover, the circuit comprising: a transmitting circuit configured to transmit signals; a receiving circuit configured to receive signals; a control circuit which, in combination with the transmitting circuit and the receiving circuit, is configured to: Receiving, from a source infrastructure equipment of a wireless communications network, an indication of one or more conditions to trigger a handover of the communication device from a source cell provided by the source infrastructure equipment to a destination cell provided by a destination infrastructure of the wireless communications network, Receiving, from the source infrastructure equipment, an evaluation trigger signal indicating to the communication device to evaluate one or more of the conditions for triggering the handover of the communication device from the source cell to the destination cell, wherein the evaluation trigger signal from the source infrastructure equipment is received by the communication device in response to a change or anticipated change of a network energy saving mode (NES) of the source cell and / or the destination cell, and, in response thereto, Evaluating one or more of the conditions for triggering the handover of the communication device from the source cell to the target cell, Determine that one or more of the evaluated conditions are met, and, in response, Initiating the handover of the communication device from the source cell to the target cell. [31] A wireless communication network comprising a source infrastructure equipment according to claim 27 and a communication device according to claim 28. [32] Computer program comprising instructions which, when loaded onto a computer, cause the computer to perform a method according to claim 1 or claim 16. [33] Non-transitory computer-readable storage medium that stores a computer program according to claim 32.

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