Extended Access Procedures

Abstract

[0003] Embodiments of the present disclosure relate to an apparatus, method, device, and computer-readable storage medium for enhanced access. A first device transmits a first message to initiate a first access to a first cell. The first device receives an access response from at least one of the first cell or a different second cell. The access response indicates that the second cell is to be accessed by the first device. The first device transmits a second message to the second cell related to the second access to the second cell.

Description

[Technical Field]

[0001] FIELD Embodiments of the present disclosure relate generally to the field of telecommunications, and more particularly to an extended access procedure computing device, method, apparatus, and computer-readable storage medium. [Background technology]

[0002] Network (NW) energy savings can be focused on the radio access network (RAN), which accounts for a large portion of the total energy consumption in the network. Unscheduled synchronization signal block (SSB) transmission can be used to achieve NW energy savings. Discontinuous transmission (DTX) can also be used to save NW energy. In NW deployments, coverage cells served by macro base stations (BSs) provide basic "underlay" coverage in specific areas of the network, and capacity cells served by small BSs are layered on top of the coverage cells for capacity boost purposes within specific zones. To achieve network energy savings, capacity cells can be deactivated or turned off during low load or idle periods. Inactive or switched-off capacity cells can be (re)activated when needed. Summary of the Invention

[0003] In a first aspect, a first device is provided, the first device comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first device to at least: send a first message to initiate a first access to a first cell; receive an access response from at least one of the first cell or a different second cell, the access response indicating that the second cell is to be accessed by the first device; and send a second message to the second cell related to the second access to the second cell.

[0004] In a second aspect, a second device is provided, the second device comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second device to at least: receive a first message from the first device at the first cell to initiate a first access to the first cell; and determine a different second cell to be accessed by the first device.

[0005] In a third aspect, a third device is provided, the third device comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the third device to at least: determine that a second cell served by the third device is accessed by the first device; determine that the first device has initiated a first access to a different first cell; and, based on the determination that the second cell is accessed by the first device, detect a second message from the first device related to the second access to the second cell.

[0006] In a fourth aspect, a method is provided that is implemented in a second device, the method including: transmitting a first message to initiate a first access to a first cell; receiving an access response from at least one of the first cell or a different second cell, the access response indicating that the second cell is to be accessed by the first device; and transmitting a second message to the second cell associated with the second access to the second cell.

[0007] In a fifth aspect, a method is provided that is implemented in a second device, the method including receiving, at a first cell, a first message from the first device for initiating a first access to the first cell, and determining a different second cell to be accessed by the first device.

[0008] In a sixth aspect, a method is provided that is implemented in a third device, the method including: determining that a second cell served by the third device is to be accessed by a first device, where the first device initiates a first access to a different first cell; and detecting, based on the determination that the second cell is to be accessed by the first device, a second message related to the second access to the second cell from the first device.

[0009] In a seventh aspect, there is provided an apparatus comprising means for carrying out a method according to the fourth, fifth or sixth aspect above.

[0010] In an eighth aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform a method according to at least one of the fourth, fifth or sixth aspects above.

[0011] It should be understood that the Summary is not intended to identify key features or essential features of the embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become readily apparent through the following description. [Brief explanation of the drawings]

[0012] Exemplary embodiments will now be described with reference to the accompanying drawings. [Figure 1] FIG. 1 illustrates an example of an environment in which exemplary embodiments of the present disclosure may be implemented. [Figure 2] FIG. 2 illustrates an example signaling diagram of an access procedure in accordance with some example embodiments of the present disclosure. [Figure 3A] FIG. 3A illustrates an example process for extended access in accordance with some other exemplary embodiments of the present disclosure. [Figure 3B] FIG. 3B illustrates an example process for extended access in accordance with some other exemplary embodiments of the present disclosure. [Figure 3C]FIG. 3C illustrates an example process for extended access in accordance with some other exemplary embodiments of the present disclosure. [Figure 3D] FIG. 3D illustrates an example process for expanded access in accordance with some other exemplary embodiments of the present disclosure. [Figure 4] FIG. 4 shows a flowchart of an exemplary method for enhanced access, according to some exemplary embodiments of the present disclosure. [Figure 5] FIG. 5 shows a flowchart of an exemplary method for enhanced access, according to some exemplary embodiments of the present disclosure. [Figure 6] FIG. 6 shows a flowchart of an exemplary method for enhanced access according to some other exemplary embodiments of the present disclosure. [Figure 7] FIG. 7 is a simplified block diagram of an apparatus suitable for practicing exemplary embodiments of the present disclosure. [Figure 8] 8 shows a block diagram of an exemplary computer-readable medium in accordance with some exemplary embodiments of the present disclosure. Throughout the drawings, identical or similar reference numerals represent identical or similar elements. DETAILED DESCRIPTION OF THE INVENTION

[0013] The principles of the present disclosure will now be described with reference to some exemplary embodiments. It should be understood that these embodiments are provided for illustrative purposes to help those skilled in the art understand and practice the present disclosure, and are not intended to imply any limitations on the scope of the present disclosure. The disclosure described herein may be implemented in various forms other than those described below.

[0014] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0015] References in this disclosure to "one embodiment," "embodiment," "exemplary embodiment," etc. indicate that the described embodiment may include a particular feature, structure, or characteristic, but not all embodiments need include the particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is understood that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments, whether or not explicitly stated.

[0016] Although terms such as "first" and "second" may be used herein to describe various elements, it should be understood that these elements are not limited by these terms. These terms are merely used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of the exemplary embodiments. As used herein, the term "and / or" includes any and all combinations of one or more of the listed terms.

[0017] The terminology in the examples is for the purpose of describing particular embodiments and is not intended to limit the exemplary embodiments. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that as used herein, the terms "comprises," "comprising," "has," "having," "includes," and / or "including" specify the presence of stated features, elements, and / or components, etc., but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof.

[0018] As used herein, "at least one of: ", "at least one of ", and similar expressions where a list of two or more elements is joined by "and" or "or" mean at least any one of the elements, or at least any two or more of the elements, or at least all of the elements.

[0019] As used herein, unless expressly stated, performing a step "in response to A" does not indicate performing the step immediately after "A" occurs, which may include one or more intervening steps.

[0020] The terminology in the examples is for the purpose of describing particular embodiments and is not intended to limit the exemplary embodiments. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that as used herein, the terms "comprises," "comprising," "has," "having," "includes," and / or "including" specify the presence of stated features, elements, and / or components, etc., but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof.

[0021] As used in this application, the term "circuit" means (a) hardware-only circuit implementations (e.g., analog and / or digital-only implementations); and (b) a combination of hardware circuitry and software (if applicable); (i) a combination of analog and / or digital hardware circuitry and software / firmware; (ii) any part of a hardware processor with software (including digital signal processors, software, and memory that work together to cause a device, such as a mobile phone or server, to perform various functions); and (c) A hardware circuit or processor, such as a microprocessor or part of a microprocessor, that requires software (e.g., firmware) to operate, but the software may be absent when not required for operation; It may refer to one or more or all of the following:

[0022] This definition of circuit applies to all uses of the term in this application, including any claims. As a further example, as used herein, the term circuit also covers simply a hardware circuit or processor (or processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware implementation. The term circuit also covers, for example, a baseband or processor integrated circuit for a mobile device, or a similar integrated circuit in a server, cellular network device, or other computing or network device, if applicable to the particular claim element.

[0023] As used herein, the term "communication network" refers to a network conforming to any suitable communication standard, such as New Radio (NR), Long Term Evolution (LTE), LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed ​​Packet Access (HSPA), Narrowband Internet of Things (NB-IoT), 6G, or any future standard. Furthermore, communication between terminal devices and network devices in the communication network may be based on first-generation (1G), second-generation (2G), 2.5G, 2.75G, third-generation (3G), fourth-generation (4G), 4.5G, fifth-generation (5G) cellular communication protocols, wireless local area network communication protocols such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, and / or other protocols currently known or developed in the future. Embodiments of the present disclosure may be applied to various communication systems. Given the rapid development of communications, there will, of course, be future communication technologies and systems in which the present disclosure may be embodied. It should not be understood that the scope of the present disclosure is not limited to only the aforementioned systems.

[0024] As used herein, the term "base station" or (BS) refers to equipment in a communication network through which terminal devices access the network and receive services therefrom. A base station may include a transmit / receive point (TRP), an access point (AP), a Node B (NodeB or NB), an evolved Node B (eNodeB or eNB), an NRNB (also referred to as a gNB), a remote radio unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, a low-power node such as a femto node or a pico node, an access point, etc., depending on the terminology and technology applied.

[0025] As used herein, the term "macro base station" or "macro BS" refers to a base station that covers a wider area, such as a coverage cell. Examples of macro base stations can include a Node B (NodeB or NB), an evolved Node B (eNodeB or eNB), and an NRNB (also referred to as a gNB). As used herein, the term "small base station" or "small BS" refers to a base station that covers a smaller area, such as a capacity cell. In some exemplary embodiments, small BSs can support network energy conservation and provide cells that can be in an inactive, sleep, DTX, or OFF mode for power savings.

[0026] The terms "active," "switched ON," and "turned ON" can be used interchangeably. A switched-off (or switched-off) cell, turned-off cell, inactive cell, inactive cell, or deep-sleep cell refers to a cell in which all (most) of its components are turned off. The terms switched off, "turned off," "deactivated," "inactive," and "deep-sleep" can be used interchangeably. A sleeping cell or cell in sleep mode refers to a cell in an intermediate state in which the cell has some of its components turned on but others turned off.

[0027] The term "terminal equipment" refers to any terminal equipment capable of wireless communication. By way of example and not limitation, a terminal equipment may also be referred to as a communication device, a user equipment (UE), a subscriber station (SS), a mobile subscriber station, a mobile station (MS), or an access terminal (AT). Terminal equipment includes, but is not limited to, mobile phones, cellular phones, smartphones, voice over IP (VoIP) phones, wireless local loop phones, tablets, wearable terminal equipment, personal digital assistants (PDAs), portable computers, desktop computers, image capture terminal equipment such as digital cameras, gaming terminal equipment, music storage and playback equipment, in-vehicle wireless terminal equipment, wireless endpoints, mobile stations, laptop embedded devices (LEEs), laptop embedded devices (LMEs), USB dongles, smart devices, wireless customer premises equipment (CPEs), Internet of Things (IoT) devices, wearables such as watches, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in the context of industrial and / or automated processing chains), consumer electronics devices, devices operating in commercial and / or industrial wireless networks, etc. In the following description, the terms "terminal equipment," "terminal," "user equipment," and "UE" can be used interchangeably.

[0028] Network (NW) energy conservation can focus on the Radio Access Network (RAN), which consumes the largest portion of total energy consumption in the network. NW energy conservation can aim to identify transmission and / or reception adaptation techniques in time, frequency, space, and power domains, with potential assistance or feedback from User Equipment (UE), potential UE assistance information, and information exchange or coordination over the network interface.

[0029] Network energy savings can be achieved by reducing the frequency of synchronization signal block (SSB) transmissions. For example, an SSB periodicity of 160 ms may be considered in empty or low-load situations in fifth-generation (5G) non-standalone (NSA) deployments. Micro-discontinuous transmission (DTX) may also be used for network energy savings, which may include, for example, shutting down the power amplifier (PA) every OFDM symbol in symbols that carry neither data nor signaling. Further components, such as baseband (BB) circuits, can be shut down to conserve network energy. Alternatively, or in addition, entire cells may be turned off or shut down. Such cell shutdowns can turn off most of the hardware components at the RAN site.

[0030] In a network deployment, the coverage area of ​​a cell (also called a coverage cell) served by a macro base station (BS) provides basic "underlay" coverage in a specific area of ​​the network. Small cells (also called capacity cells) served by small BSs are overlaid on the coverage cell for capacity enhancement purposes, especially in so-called "hotspot zones." Capacity cells can be deactivated or switched off during low load or idle periods to achieve network energy savings. All active components of the cell can be turned off to reduce energy consumption.

[0031] The time it takes for components to be switched OFF or ON to achieve deactivation or activation of a capacity cell can be quite long. In this case, an intermediate state (sleeping state) can be defined in which some (or most) components are turned off and others are activated as needed. For example, the PA can be activated occasionally to schedule lean signaling such as beacons and synchronous system blocks (SSBs) for cell discovery, while the main receiver and other components can be turned off to save energy.

[0032] Cell activation can be controlled by the network. A cell activation request from a neighboring node, e.g., a cell activation procedure over the Xn or X2 interface, can be used to trigger the (re)activation of a switched-off cell. The trigger for cell activation may be based on the cell load and the need to offload part of the cell's traffic to one or more cells that are currently switched off. The trigger for cell activation may also be based on the aggregated load across a cluster of cells (also called a power-saving group), such as the load of cells that make up a coverage layer or a particular frequency layer.

[0033] Exemplary embodiments of the present disclosure propose an extended access scheme that extends an access procedure initiated by a first device (e.g., terminal equipment) toward a cell (referred to as a first cell) to a different cell (referred to as a second cell). In some exemplary embodiments, the first cell may be a coverage cell, and the second cell may be a capacity cell in an inactive, sleep, DTX, or OFF state or mode. In this scheme, after the first device transmits a message (referred to as a first message) to initiate access to the first cell (referred to as a first access), the first message may be received or detected by at least one of the first cell or the second cell. The first message may comprise any type and / or format of message used to initiate the first access. For example, the first message may include a message 1 (Msg1) of a four-step random access (RA) procedure, a message A (MSGA) of a two-step random access procedure, and / or the like. The first message may be implemented in the form of a Physical Random Access Channel (PRACH) preamble transmitted over a PRACH channel, a wake-up signal transmitted over another channel, and / or an equivalent predetermined sequence.

[0034] From at least one of the first cell or the second cell, the first device receives an access response, such as a random access response (RAR) or message 2 (e.g., Msg2 of a four-step random access (RA) procedure). The access response indicates that the second cell is to be accessed by the first device. Furthermore, the first device transmits a message (referred to as a second message) related to accessing the second cell (referred to as a second access). The second message may comprise any type and / or format of message related to the second access. For example, the second message may comprise message 3 (Msg3) of a four-step random access procedure in response to the RAR or Msg2, Msg1 to initiate a new random access procedure, a wake-up signal or indication transmitted using an existing or new signal or channel, and / or the like.

[0035] In this way, after a device (such as a UE) requests a cell to provide service, different cells can be enabled or activated to provide the service based on the needs of the requesting device (traffic or service needs, radio conditions, etc.), which is more flexible and practical, and can improve the probability of successful access and further improve the performance or efficiency of the network.

[0036] FIG. 1 illustrates an exemplary environment 100 in which exemplary embodiments of the present disclosure may be implemented.

[0037] An environment 100, which may be part of a communications network, includes a macro BS 110 serving a coverage cell 115. Within the coverage cell 115 resides a plurality of terminal devices and a plurality of small BSs. As shown in FIG. 1, the terminal devices are located in both the coverage cell 115 and in a capacity cell 125 served by a small BS 130. The coverage cell 115 provides basic coverage in the environment 100, and the capacity cell 125 is overlaid on the coverage cell 115 for a capacity boost. The terminal devices 120 can be served by either the coverage cell or the capacity cell.

[0038] It should be understood that the number of macro BSs, small BSs, and terminal devices is shown in FIG. 1 for illustrative purposes only, without implying any limitation. Environment 100 may include any suitable number of macro BSs, small BSs, and terminal devices compatible with implementation in exemplary embodiments of the present disclosure. Any suitable number of small BSs and terminal devices may be located within the coverage area of ​​each of the macro BSs.

[0039] It will also be understood that the small BSs 130 are shown physically separate from the macro BS 110 for illustrative purposes only. The small BSs 130 may have any suitable location relationship to the macro BS 110. Accordingly, the capacity cells 125 may be overlaid on top of the coverage cells 115 in any suitable pattern to improve capacity in any "hot spot zones." In some exemplary embodiments, the small BSs 130 may be co-located with the macro BS 110 or may be implemented as part of the macro BS 110. In these embodiments, the capacity cells 125 and coverage cells 115 may be concentric or co-located.

[0040] Terminal equipment 120 can communicate with macro BS 110 and can communicate with small BS 130 directly or via macro BS 110. Terminal equipment 120 can communicate with other terminal equipment directly or via BSs 110 and / or 130. Small BS 130 can communicate with macro BS 110 via wireless and / or wired means. As an example in one example, terminal equipment 120 and two BSs 110 and 130 may communicate via a Uu interface, and two BSs 110 and 130 may communicate via an Xn or X2 interface.

[0041] Communications in the environment 100 may utilize any suitable wireless communication technology, including, but not limited to, code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), frequency division duplex (FDD), time division duplex (TDD), multiple input multiple output (MIMO), orthogonal frequency division multiple access (OFDM), discrete Fourier transform spread OFDM (DFT-s-OFDM), Bluetooth®, ZigBee®, machine type communications (MTC), enhanced mobile broadband (eMBB), massive machine type communications (mMTC), ultra-reliable low latency communications (URLLC), carrier aggregation (CA), dual connection (DC), new unlicensed radio (NR-U), small data transmission (SDT), and / or other technologies now known or developed in the future.

[0042] Within the coverage cell 115, multiple capacity cells may be turned ON or OFF, for example, to offload traffic from the macro BS 110, to boost the capacity of the coverage cell 115, and / or depending on the needs of the network. During periods of low load or vacancy in the coverage cell 115, the capacity cell 125 may be in a power-saving state (such as an inactive state, a sleeping state, an OFF state, and / or a DTX state or mode) to achieve network energy savings. All active components of the capacity cell 125 may be deactivated to achieve energy consumption reduction. In the power-saving state, paging procedures, PRACH, or SSBs or SIBs may not be supported in the capacity cell 125, which may be waiting for an activation request.

[0043] In the environment 100, the terminal device 120 may be camped within the coverage cell 115 but may be in an inactive or idle state, such as a radio resource control (RRC) inactive or idle state. Triggered by the presence of uplink (UL) and / or downlink (DL) data and / or signaling, the terminal device 120 may initiate access to the coverage cell 115. Access to the coverage cell 115 may extend to the capacity cell 125.

[0044] Exemplary embodiments of such access extensions are described below with reference to FIGS.

[0045] 2 shows an example signaling diagram 200 of an access procedure according to some example embodiments of the present disclosure. For illustrative purposes, diagram 200 will be described with reference to FIG.

[0046] In diagram 200, a first device 205 (e.g., terminal equipment 120) transmits (207) a first message to initiate a first access to a first cell (e.g., coverage cell 115). A second device 210 (e.g., macro BS 110) serving the first cell receives (212) the first message.

[0047] In some exemplary embodiments, a third device 215 serving the second cell (such as capacity cell 125) may also receive 216 the first message. Coordination between the second device 210 and the third device 215 may be required so that the third device 215 obtains the configuration of the first message for receiving the message. For example, the second device 210 may send to the third device 215 an indication of resources for detecting the first message from the first device 205. The resources may include resources in the time, frequency, special, and / or code domains. In this way, the third device 215 may know which time and / or frequency resources, which beam, and / or which preamble the first device 205 may use to transmit the first message. Furthermore, the third device 215 may detect the first message from the first device 205 using the resources indicated by the second device 210.

[0048] The second and third devices 210 and 215 can have any suitable positional relationship. The two devices 210 and 215 can be separate from one another or can cooperate with one another. In some exemplary embodiments, the third device 215 can be implemented as part of the second device 210. Thus, the second cell can be separate from the first cell, partially overlapping, overlapping, or concentrically arranged.

[0049] It should be understood that the first, second, and third devices 205, 210, and 215 may be implemented by any suitable devices. Some exemplary embodiments will be described taking terminal equipment 120 as an example of the first device 205, macro BS 110 as an example of the second device 210, and small BS 130 as an example of the third device 215. Other implementations of these devices 205, 210, and 215 are possible, and the scope of the present disclosure is not limited in this respect. As an example, second device 210 and third device 215 may be any other device capable of covering an area to support service for first device 205. First device 205 may be any other device that needs to access the coverage areas of second and third devices 210 and 215 to obtain a requested service.

[0050] The first message for initiating first access to the first cell may include any suitable type of message in any suitable format. In some exemplary embodiments, the first device 205 may initiate an RA procedure to access the first cell. For example, in response to an event trigger, the first device 205 may initiate a contention-based random access (CBRA) procedure or a four-step RA procedure, or may initiate a contention-free random access (CFRA) procedure or a two-step random access procedure. The first message includes Msg1 in a four-step RA procedure and MSGA in a two-step random access procedure. The first message may be implemented in the form of a preamble, a wake-up signal, and / or an equivalent predetermined sequence transmitted on a PRACH channel or another channel.

[0051] After receiving (212) the first message, the second device 210 determines (217) that the second cell is to be accessed by the first device 205. In some exemplary embodiments, the second device 210 may make the determination itself. The determination may be made by the second device 210 by considering the traffic type requested by the first device 205. For example, the second device 210 may identify the traffic type or service type requested by the terminal equipment 210. The traffic type or service type may be indicated by the first message. For example, in an exemplary embodiment in which the first device 205 initiates an RA procedure for first access to the first cell, the first device 205 may select a preamble or specific PRACH resource associated with the requested traffic type. Thus, the second device 210 may determine the requested traffic type based on the selected preamble or resource.

[0052] As an example, if the requested traffic is delay-tolerant traffic, i.e., the traffic is relatively non-urgent, the second device 210 may decide to switch access from the first cell to the second cell because such a switch may require some processing time. If the traffic is URLLC traffic, the second device 210 may decide not to perform such a switch.

[0053] As another example, if the first device 205 selects a small data transmission (SDT) dedicated PRACH resource and only a small data exchange is requested or expected, the second device 210 may decide not to switch access. If a relatively large data exchange is requested, the second device 210 may determine that a second cell is to be accessed by the first device 205.

[0054] In an exemplary embodiment, the decision may be made based on the load of the first and / or second cell. For example, if the load of the first cell is relatively high and / or the load of the second cell is relatively low, it may be decided to access the second cell. If the load of the first cell is relatively low and / or the load of the second cell is relatively high, the second cell may not be accessed.

[0055] Alternatively, or additionally, the determination may be based on the location of the first device 105. Any suitable positioning technique may be used to determine or estimate the location of the first device 105. In some exemplary embodiments, the second device 210 may determine the location of the first device 105 based on measurements of the time of arrival (ToA) and angle of arrival (DL-AoA) of a signal received from the first device 205 on a channel such as a PRACH. Based on the location of the first device 105, the second device 210 may determine whether to access the second cell. For example, if the first device 205 is located in the second cell, the second cell is accessed by the first device 205. Otherwise, the first device 205 can still access the first cell.

[0056] Alternatively, or additionally, the second device 210 may make the determination based on radio conditions associated with the first and / or second cells. The radio conditions may be determined or evaluated based on a channel estimate of a communication channel with the first device 205. Any suitable channel estimation approach or algorithm may be used, and the scope of the present disclosure is not limited in this respect. As an example, one of the first and second cells having better radio conditions may be accessed by the first device 205.

[0057] In some demonstrative embodiments, after determining 217 that the second cell is to be accessed by the first device 205, the second device 210 may send an indication to the third device 215 indicating that the second cell is to be accessed by the first device 205. The indication may include an identification of the first device 205 so that the third device 215 can identify subsequent messages from the first device 205. In one example, the indication may be that the second device 210 forwards the first message to the third device 210. Other implementations of the indication are possible. Some other implementations of the indication are described in the following paragraphs.

[0058] In some exemplary embodiments, the second cell (e.g., a capacity cell) may be in a power-saving state, such as an inactive state, a sleep state, an OFF state, and / or a DTX state, to conserve energy. In these exemplary embodiments, the second device 210 may send a request to the third device 215 to activate the second cell. The third device 215 may then wake up the second cell. The request may be communicated over an Xn or X2 interface when the second and third devices 210 and 215 are implemented by the macro BS 110 and small BS 130, respectively.

[0059] After the second cell is activated, the third device 215 may broadcast at least a synchronization signal block (SSB) in the second cell so that the first device 205 can subsequently acquire synchronization with the second cell. The third device 215 may also broadcast a system information block (SIB) in the second cell so that the first device 205 can obtain information necessary for subsequent communication.

[0060] Alternatively, or additionally, the second device 210 may make the decision in coordination (212) with the third device 215. For example, in an exemplary embodiment in which the third device 215 may receive (214) the first message, the second device 210 and the third device 215 may coordinate with each other based on the load of the first and / or second cells, the traffic type requested by the first device, the location of the first device, and / or radio conditions associated with the first and / or second cells, and / or the like.

[0061] After it is determined that the second cell is to be accessed, the first device 205 receives (207) an access response indicating that the second cell is to be accessed by the first device 205. In some exemplary embodiments, the access response received by the first device 205 may include identification information of the second cell, such as a physical cell identifier (PCI), indicating which cell is to be accessed. The access response may be implemented in any appropriate message. For example, in an exemplary embodiment in which the RA procedure is initiated by the first device 205, the access response may include a random access response (RAR) message, which may be implemented in message 2 (Msg2) in a four-step RA procedure and / or message B (MsgB) in a two-step RA procedure.

[0062] The access response may be extended to indicate access to the second cell (rather than the first cell). For example, the access response may include an information element (IE) indicating that the first device 205 may need to complete the remaining steps of the access procedure in the second cell. If a four-step RA procedure is used, the steps may consist of sending Msg3, monitoring message 4 (Msg4), and / or the like. Other steps, such as network synchronization, system information block 1 (SIB1), etc., may also be completed in the second cell.

[0063] In some exemplary embodiments, if the second cell (e.g., a capacity cell) is in a power saving state, such as an inactive state, a sleep state, an OFF state, and / or a DTX state for energy conservation, the access response may further include an indication of the availability time of the second cell to indicate to the terminal device when the second cell is available or activated to further improve the probability of successful access to the second cell. The availability time may depend on the particular state or mode of the second cell at the time of receipt of the first message and / or the fast reactivation capability of the second cell.

[0064] Alternatively or additionally, the access response may include instructions for resources, beams, and / or timing for accessing the second cell, based on which the first device 205 can access the second cell.

[0065] The access response can be received by the first device 205 from the first and / or second cell. As shown in FIG. 2, for example, the second device 210 may transmit (224) the access response to the first device 205. In response to the first message received from the first device 205, the second device 210 may generate and then transmit the access response to the first device 205. When the terminal device 120 functions as the first device 205 and the macro BS 110 functions as the second device 210, the access response can be transmitted from the second device 210 to the first device 205 via the Uu interface.

[0066] In an exemplary embodiment, the second device 210 may send an access response to the third device 215. The access response may be used as an indication that the second cell is accessed by the first device 205. In an exemplary embodiment, in which the access response includes a configuration for communication with the first device 205, the third device 215 may use this configuration for future communications.

[0067] In some demonstrative embodiments, the access response may be generated by the third device 215. As shown in FIG. 2, the third device 215 may transmit (226) the access response to the first device 205 directly or via the second device 210. For example, after the third device 215 detects a first message from the first device 205 to initiate a first access to the first cell and further determines that the first device 205 will access the second cell, the third device 215 may transmit the access response from the second cell to the first device 205.

[0068] In an exemplary embodiment, the second device 210 can forward the access response from the second cell to the first device 205. For example, the third device 215 sends the access response to the second device 210, which then relays it to the first device 205.

[0069] In some exemplary embodiments, the first device 205 may be associated with the second cell and may receive an indication of resources to be used to receive an access response from the first and / or second cell. The resources may include resources in the time, frequency, space, and / or coding domains. As an example, the resources may include a search space of a physical downlink control channel (PDCCH) or other control channel in the second cell.

[0070] For example, the second device 210 may send the indication to the first device 205 via system information (SI) and / or radio resource control (RRC) signaling. As another example, the third device 215 may send the indication to the first device 205 in the second cell via SSB and / or SIB after the second cell leaves the DTX or sleep state.

[0071] Thus, the first device 205 can monitor the indicated resources to receive an access response from the second cell, and the first device 205 can monitor resources associated with the first cell to receive an access response from the first cell.

[0072] After receiving 222 the access response, the first device 205 transmits 228 a second message associated with the second access to the second cell, which causes 230 the third device 215 to receive the second message. To enable communication of the second message, the access response may include an indication of resources for transmission of the second message by the first device 205.

[0073] Alternatively, or additionally, the access response may include an indication of a beam and / or timing advance (TA) for transmission of the second message. For example, the second device 210 may locate the first device 205 based on ToA and / or AoA measurements. The second device 210 may then estimate the distance between the first device 205 and the second cell. By doing so, the second device 210 may determine a TA and potential beam for transmission of the second device 210 in the second cell. In some other embodiments, if the first and second cells are co-located, the TA obtained based on measurements in the first cell may also be valid for the second cell.

[0074] In some embodiments, when the availability time of the second cell is indicated to the first device 205, the first device 205 may first determine whether the second cell is available. If the second cell is available, the first device 205 may transmit a second message to the second cell. Before transmitting the second message, the first device 205 may detect at least an SSB from the second cell for network synchronization. The first device 205 may further detect a SIB to obtain information necessary for communication with the third device 210 in the second cell.

[0075] The second message may include any suitable type of message. In some exemplary embodiments, the second message may be Msg3 in a four-step RA procedure or any other message that includes identification of the first device 205 for contention resolution. If Msg3 is used as an example of the second message, transmission of Msg3 may be targeted to the second cell as the receiving cell.

[0076] After receiving 230 the second message, the third device 215 may send 232 a response message to the first device 205. In embodiments in which Msg3 is sent as the second message, the third device 215 may send Msg4.

[0077] In some exemplary embodiments, the second message may be Msg1 in a four-step RA procedure, MSGA in a two-step RA procedure, or another message for initiating second access to the second cell. For example, if Msg1 is sent from the first device 205 as the second message toward the second cell, the third device 215 may respond with Msg2 from the second cell. If the first and second cells are co-located, the first device 205 may send Msg1 toward the capacity cell using the beam direction of the first message to initiate first access to the first cell.

[0078] In some embodiments, when an RA procedure is used by the first device 205 (e.g., a UE) toward a coverage cell (as an example of a first cell), the RA procedure may be extended for activation of a capacity cell (as an example of a second cell). In such an extended RA procedure, the first device 205 can initiate a RACH procedure in the coverage cell (by transmitting a PRACH to the coverage cell), and the first device 205 can transmit or receive at least one RACH message (e.g., one of a four-step RACH message) to or from the capacity cell. Some embodiments of a two-cell process based on an RA procedure are described below with reference to Figures 3A, 3B, 3C, and 3D.

[0079] Reference is first made to FIG. 3A, which illustrates a first exemplary process 300 for expanded access in accordance with some exemplary embodiments of the present disclosure.

[0080] In this embodiment, the coverage cell 305 (denoted as cell 11) and the capacity cell 310 (denoted as cell 2) are examples of the first and second cells. A UE 315 functions as the first device 205. The UE 315 can communicate Msg1 and enhanced Msg2 (of the four-step RACH) with the coverage cell and Msg3 and Msg4 with the capacity cell. As an example, the UE 315 can be configured for an enhanced two-cell RACH mode and receive corresponding configuration so that the UE 315 knows with certainty which cell and which resource to monitor the PDCCH or physical downlink shared channel (PDSCH) carrying the RACH message.

[0081] 3A, triggered by the presence of UL / DL data, the UE 315 may initiate 320 an RA procedure by transmitting a Physical Random Access Channel (PRACH) preamble toward the coverage cell 305. In one embodiment, the service type requested by the UE 315 may be identified by the network from the selected preamble.

[0082] A decision may be made at 322 to activate the capacity cell 310 in sleep mode or off mode at 324. A cell activation request may then be sent to the capacity cell 310 (e.g., through Xn signaling) (326). This activation decision in one embodiment may be made based on network load. Additionally or alternatively, this decision may be based on the traffic type requested by the UE 315, for example, whether the request can be triggered for delay-tolerant traffic. Additionally or alternatively, the decision and selection of the capacity cell may depend on the location of the UE, which may be determined based on the received PRACH. In one embodiment, the access request may be forwarded from the UE 315 to the capacity cell 310.

[0083] An extended random access response (RAR) message may be generated in the coverage cell 305 in response to the PRACH reception. The extended RAR message may be transmitted (328) to the UE 315. The extended RAR message may include content that indicates to the UE 315 that the extended RACH mode is enabled, in which case the UE 315 should transmit Msg3 of the RACH procedure to another cell (cell 2) different from the cell providing the RAR message (cell 1) and monitor Msg4 from that cell (cell 2).

[0084] In some embodiments, the enhanced RAR message may include a new IE, e.g., a "Capacity Cell Mode" IE (or "Enhanced RACH Mode" or "Two Cell RACH Mode"), that includes the PCI of the capacity cell 310 (as an example embodiment of the identification of the capacity cell 310) to indicate that the UE 315 may need to complete the remaining steps of the RACH procedure in a given capacity cell. Additionally, other procedures, such as NW synchronization, SIB1 acquisition, and Msg4 monitoring opportunities, may also be completed in the capacity cell 310.

[0085] In some exemplary embodiments, the presence of the capacity cell 310 may be indicated via system information (SI) from the coverage cell 305. In one example, the indication may include a capacity cell ID. In one option, the indication may be provided in the SI. In another option, the indication may be provided in RRC signaling, such as a paging message. As shown in FIG. 3A, as an alternative, the cell 2 ID may be transmitted 329 from the coverage cell 305 to the UE 315 via SIB1.

[0086] If the UE 315 may need to transmit Msg3 to a capacity cell according to the configured enhanced RACH mode, a timing advance (TA) for the transmission of Msg3 (or a transmission delay of Msg3) may be calculated and provided to the UE 315 as part of the RAR message based on information about the capacity cell. For example, ToA and AoA measurements may be performed on the received PRACH, after which a coarse location of the UE may be determined. Based on the location of the capacity cell, the distance between the UE 315 and the capacity cell 310 may be estimated. In another embodiment, if the coverage cell 305 and the capacity cell 310 are co-located, the TA obtained based on the PRACH of the coverage cell 305 is also valid for the capacity cell 310.

[0087] In an exemplary embodiment, an indication of the availability time of the capacity cell 310, which may depend on the sleep mode the capacity cell 310 is in at the time of PRACH reception and the fast reactivation capability of the capacity cell 310, may also be included in the enhanced RAR message and provided to the UE 315. An indication of the resource allocation for the capacity cell 310 may also be included in the enhanced RAR message.

[0088] For a given enhanced RACH mode, which messages to monitor or send to other cells may be defined in the standard, provided in the RAR message, or configured in the SIB of the coverage cell 305. The enhanced RAR may be sent from the coverage cell 305 to the UE 315 over the Uu interface and to the capacity cell 310 over the Xn interface.

[0089] The UE 315 may receive the enhanced RAR message and apply the received information or configuration related to the enhanced RACH mode. For example, if received, the UE 315 may consider the availability time of the capacity cell 310 before transmitting Msg3 to the capacity cell 310. As shown in FIG. 3A, at 330, the PRACH transmission to cell 2 may be delayed according to the Msg1 transmission delay.

[0090] The RAR message, which may be received 332 at the capacity cell 310, may include an Msg3 resource allocation provided to the UE 315, based on which monitoring for Mgs3 from the UE 315 may be performed at the capacity cell 310. For example, the RAR message may inform the capacity cell 310 of when and where Msg3 may be received from the UE 315 at the capacity cell 310, and a temporary C-RNTI (TC-RNTI) that the UE 315 may be assigned and used in Msg3.

[0091] Once (re)activated, reference signals such as SSBs and optional SIBs may be transmitted (336) from the capacity cell 310, received by the UE 315, and used (338) to acquire network synchronization and SI.

[0092] After synchronizing with the capacity cell 310 and obtaining the necessary information from the SIB, the UE 315 can send 340 Msg3 to the capacity cell 310 to complete the RRC connection establishment towards the capacity cell 310. The transmission of Msg3 may be targeted to the capacity cell 310 as the receiving cell, which may include generating and populating an RRC resume request message for the UE 315 in RRC inactive mode using the PCI of the capacity cell 310 for RRC level integrity protection.

[0093] In this example, the transmission of Msg3 may be performed using a UE Tx beam based on the best UE Tx beam toward the coverage cell 305. This may assume co-location and FR1 operation between the coverage cell 305 and the capacity cell 310. In one example, the UE 315 may use the same UE Tx beam for the Msg3 transmission as used for the PRACH transmission. In the case of co-location FR1, the UE's Rx and Tx beams toward the two cells 305 and 310 are considered to be the same. In another example, the transmission of Msg3 may be performed using the UE Tx beam indicated in the RAR message based on a mapping between the UE Tx beam in the coverage cell 305 and the UE Tx beam in the capacity cell 310. For example, the same beam or a wider beam may be used in the capacity cell 310 compared to the coverage cell 305.

[0094] Msg3 may be monitored (341) in the capacity cell 310. Msg4 may then be transmitted (342) from the capacity cell 310 to the UE 315. The UE 315 may monitor (344) Msg4 from the capacity cell 310.

[0095] FIG. 3B illustrates a second exemplary process 350 for expanded access according to some exemplary embodiments of the present disclosure.

[0096] In this example, the PRACH and RAR are transmitted to and from coverage cell 305, followed by transmission of Msgs 1, 2, 3 and 4 in capacity cell 310.

[0097] The actions and operations in 320 to 338 of the second process 350 are similar to those in the first process 300. The difference is that in the enhanced RACH mode of the process 350, the UE 315 may have to perform random access in the capacity cell 310 (cell 2).

[0098] The enhanced RAR message in this embodiment may include PRACH resource information for the capacity cell 310. This may include all PRACH information that may be included in the SIB (although the UE may not need to read the SIB from the capacity cell 310) and / or dedicated preamble allocation for contention-free random access.

[0099] The extended RAR message received at 332 may indicate that the UE 315 may be attempting to transmit on the PRACH and the PRACH resources to be used. This message may inform the capacity cell 310 about when and where it may be able to receive Msg1 from the UE 315.

[0100] After synchronizing with the capacity cell and obtaining the necessary information from the SIB, the UE 315 can initiate 352 random access at 338 and complete the establishment of an RRC connection towards the capacity cell 310 .

[0101] FIG. 3C illustrates a third example process 355 for expanded access according to some other example embodiments of the present disclosure.

[0102] In a third process 355, the UE 315 may attempt 356 an RA to the coverage cell 305 by transmitting a preamble on the PRACH and waiting for an RA response. The PRACH is listened to by both the coverage cell 305 and the capacity cell 310, and the UE 315 may be responded to by the capacity cell 310.

[0103] The capacity cell 310 can coordinate (357) with the coverage cell 305. Coordination with the coverage cell 305 may be required to agree on which cell will be used to respond to the UE 315. Coordination may also be required for the capacity cell 310 to obtain the RACH configuration for cell 1 so that it can monitor (359) the RACH initiated for cell 1.

[0104] The UE 315 may monitor 361 the PDCCH search space associated with the coverage cell 305 and / or the capacity cell 310 to receive the RAR from cell 2. The need and associated configuration to monitor the RAR from cell 2 may be provided by cell 1. Alternatively, the UE 315 may initiate monitoring for the RAR from cell 2 upon an implicit or explicit indication from cell 2. An example of an implicit indication is the transmission of an SSB or SIB from cell 2.

[0105] FIG. 3D illustrates a fourth exemplary process 365 for expanded access according to some other exemplary embodiments of the present disclosure.

[0106] The fourth process 365 of FIG. 3D is similar to the third process 355 of FIG. 3C. The difference is that an RA response may be prepared in the capacity cell 310 and transmitted via the coverage cell 305. The decision to allow the UE 315 to respond from the capacity cell 310 may depend on the service requested by the UE 315, which may be indicated by the PRACH resource selected by the UE 315. For example, if the UE 315 selects an SDT-specific PRACH resource and only a small data exchange is expected, cell 2 may not be reactivated and cell 1 may be used to respond to the RACH. Conversely, if a relatively large data exchange is expected and / or based on the load of cell 1, cell 2 may be requested to respond to the PRACH from the UE 315.

[0107] In some exemplary embodiments, RA procedures can be utilized to enable timely and efficient activation of sleeping cells based on the needs and conditions of the UE (such as traffic needs, radio conditions, and / or the like). In doing so, sleeping cells may be activated based on the actual needs or conditions of the UE, rather than based on an increase in average load levels in a larger geographic area, such as a coverage cell.

[0108] 4 shows a flowchart of an example method 400 of extended access in accordance with some example embodiments of the present disclosure. The method 400 may be implemented in the first device 205, as shown in FIG. 2. For purposes of explanation, the method 400 will be described from the perspective of the first device 205 with reference to FIGS. 1 and 2.

[0109] In block 405, the first device 205 transmits a first message to initiate a first access to the first cell. In block 410, the first device 205 receives an access response from at least one of the first cell or a different second cell, the access response indicating that the second cell is to be accessed by the first device. In block 415, the first device 205 transmits a second message to the second cell related to the second access to the second cell.

[0110] In some exemplary embodiments, the access response may include at least one of an identification of the second cell, an indication of resources (referred to as first resources) for transmission of the second message by the first device, an indication of an available time of the second cell, an indication of a beam for transmission of the second message, or an indication of a timing advance for transmission of the second message.

[0111] In some exemplary embodiments, to transmit the second message, the first device 205 may determine that the second cell is available based on the availability time of the second cell, and transmit the second message to the second cell based on the determination that the second cell is available.

[0112] In some exemplary embodiments, the first device 205 may receive the identification of the second cell from the first cell via at least one of system information or radio resource control signaling.

[0113] In some exemplary embodiments, to receive the access response, the first device 205 may monitor resources (referred to as second resources) associated with at least one of the first cell or the second cell to receive the access response.

[0114] In an exemplary embodiment, the second resources may include resources associated with the second cell. In some exemplary embodiments, the first device 205 may receive an indication of the resources associated with the second cell from at least one of the first cell or the second cell.

[0115] In some exemplary embodiments, to receive an indication of resources associated with the second cell, the first device 205 may receive an indication of resources associated with the second cell from the first cell via at least one of system information or radio resource control signaling.

[0116] In some exemplary embodiments, to receive an indication of resources associated with the second cell, the first device 205 may receive an indication of resources associated with the second cell from the second cell via at least one of a synchronization signal block or system information.

[0117] In some exemplary embodiments, to transmit the second message, the first device 205 can transmit the second message to the second cell using a beam, the beam including at least one of the beam used to transmit the first message to initiate first access to the first cell or the beam indicated by the access response.

[0118] In an exemplary embodiment, the first device 205 can detect at least a synchronization signal block from the second cell before transmitting the second message.

[0119] In an exemplary embodiment, to detect at least the synchronization signal block, the first device 205 can detect the synchronization signal block and the system information block from the second cell.

[0120] In some exemplary embodiments, the second message may include at least one of message 3 in a first random access procedure for a first access to the first cell or message 1 in a second random access procedure for a second access to the second cell.

[0121] In an exemplary embodiment, the first cell may comprise a coverage cell and the second cell may comprise a capacity cell.

[0122] 5 shows a flowchart of an exemplary method 500 of extended access in accordance with some exemplary embodiments of the present disclosure. Method 500 may be implemented in second device 210, as shown in FIG. 2. For purposes of explanation, method 500 will be described from the perspective of second device 210 with reference to FIGS. 1 and 2.

[0123] In block 505, the second device 210 receives, in the first cell, a first message to initiate a first access to the first cell from the first device 205. In block 510, the second device 210 determines that a different second cell is to be accessed by the first device 205.

[0124] In an exemplary embodiment, the second device 210 may further transmit to the first device 205 an access response from at least one of the first cell or a different second cell, the access response indicating that the second cell is to be accessed by the first device 205.

[0125] In some exemplary embodiments, the access response may include at least one of an identification of the second cell, an indication of a first resource for transmitting a second message associated with a second access by the first device to the second cell, an indication of an available time of the second cell, an indication of a beam for transmitting the second message, or an indication of a timing advance for transmitting the second message.

[0126] In an exemplary embodiment, to transmit the access response, the second device 210 may generate an access response and transmit the (random) access response from the first cell to the first device 205 .

[0127] In an exemplary embodiment, the second cell may be in a sleep mode or an off mode. In some exemplary embodiments, the second device 210 may further send a request to a third device 215 that serves the second cell to wake up the second cell.

[0128] In some exemplary embodiments, the second device 210 may further transmit an indication to a third device 215 serving the second cell indicating that the second cell is accessed by the first device.

[0129] In some exemplary embodiments, the second device 210 may further transmit to a third device 215 serving the second cell at least one of an identification of the first device, an indication of a first resource for transmitting a second message associated with a second access to the second cell by the first device, or an indication of a timing advance for transmitting the second message.

[0130] In some exemplary embodiments, the second message includes at least one of message 3 in a first random access procedure for a first access to the first cell or message 1 in a second random access procedure for a second access to the second cell.

[0131] In exemplary embodiments, the second device 210 may further receive an access response from a third device serving the second cell. In some exemplary embodiments, to transmit the access response, the second device 210 may transmit the access response from the second cell to the first device 205.

[0132] In some exemplary embodiments, the second device 210 may further transmit to the third device 215 an indication of resources (referred to as third resources) for detecting the first message from the first device to initiate a first access to the first cell.

[0133] In some exemplary embodiments, the second device 210 may further transmit to the first device 205 via at least one of system information or radio resource control signaling an indication of resources associated with the second cell and used to receive the access response.

[0134] In an exemplary embodiment, the second device 210 may further transmit the identification of the second cell to the first device 205 via at least one of system information or radio resource control signaling.

[0135] In an exemplary embodiment, the determination may be performed based on at least one of the load of the first and / or second cell, the traffic type requested by the first device, the location of the first device, or radio conditions associated with the first and / or second cell.

[0136] In some exemplary embodiments, the determination is made pursuant to a coordination with a second cell.

[0137] In an exemplary embodiment, the first cell may comprise a coverage cell and the second cell may comprise a capacity cell.

[0138] 6 shows a flowchart of an exemplary method 600 of extended access in accordance with some exemplary embodiments of the present disclosure. Method 600 may be implemented at third device 215, as shown in FIG. 3. For purposes of discussion, method 600 will be described from the perspective of third device 215 with reference to FIGS. 1 and 2.

[0139] In block 605, the third device 215 serving the second cell determines that the second cell is accessed by the first device 205. The first device 205 initiates a first access to a different first cell. In block 610, based on the determination that the second cell is accessed by the first device 205, the third device 215 detects a second message from the first device 205 related to the second access to the second cell.

[0140] In some exemplary embodiments, to determine that the second cell is accessed by the first device, the third device 215 may receive an indication from the second device 210 that serves the first cell indicating that the second cell is accessed by the first device, and based on receiving the indication, determine that the second cell is accessed by the first device 205.

[0141] In an exemplary embodiment, the second cell is in a sleep mode or an off mode. In some exemplary embodiments, the third device 215 can further receive a request from the second device to activate the second cell and, based on receiving the request, activate the second cell.

[0142] In some exemplary embodiments, the third device 215 may further broadcast at least a synchronization signal block in the second cell.

[0143] In an exemplary embodiment, to broadcast at least the synchronization signal block, the third device 215 can broadcast the synchronization signal block and the system information block in the second cell.

[0144] In some demonstrative embodiments, the third device 215 may receive from the second device 210 at least one of an identification of the first device 205, an indication of a first resource for transmission of the second message by the first device, or an indication of a timing advance for transmission of the second message.

[0145] In some demonstrative embodiments, to determine that the second cell is accessed by the first device 205, the third device 215 may receive from the second device 210 an indication of a third resource for detecting a first message for initiating a first access to the first cell from the first device 205, detect the first message from the first device 205 using the third resource, and determine that the second cell is accessed by the first device 205 based on the detection of the first message.

[0146] In some exemplary embodiments, to determine that the second cell is to be accessed by the first device 205, the third device 215 may, in coordination with the first cell, determine that the second cell is to be accessed based on at least one of the load of the first and / or second cell, the traffic type requested by the first device, the location of the first device, or radio conditions associated with the first and / or second cell.

[0147] In an exemplary embodiment, based on the determination that the second cell is accessed by the first device 205, the third device 215 may further transmit an access response in the second cell toward the first device, the access response indicating that the second cell is accessed by the first device 205.

[0148] In an exemplary embodiment, the access response may include at least one of an identification of the second cell, an indication of a first resource for transmission of the second message by the first device, an indication of an available time of the second cell, an indication of a beam for transmission of the second message, or an indication of a timing advance for transmission of the second message.

[0149] In some exemplary embodiments, the third device 215 may further transmit to the first device 205, via at least one of a synchronization signal block or a system information block, in the second cell, an indication of resources associated with the second cell and used to receive the access response.

[0150] In some exemplary embodiments, to send an access response toward the first device 205, the third device 215 may send an access response toward the first device to the second device 210 that serves the first cell.

[0151] In some exemplary embodiments, the second message may include at least one of message 3 in a first random access procedure for a first access to the first cell or message 1 in a second random access procedure for a second access to the second cell.

[0152] In an exemplary embodiment, the first cell may comprise a coverage cell and the second cell may comprise a capacity cell.

[0153] All operations and features as described above with reference to Figures 1 to 3D are equally applicable and have similar effect to methods 400, 500 and 600, and details are omitted for the sake of brevity.

[0154] In some exemplary embodiments, an apparatus capable of performing method 400 (e.g., first device 205 as shown in FIG. 2 ) may comprise means for performing each step of method 400. The means may be implemented in any suitable form. For example, the means may be implemented in a circuit or a software module.

[0155] In some exemplary embodiments, the apparatus comprises means for transmitting a first message to initiate a first access to a first cell; means for receiving an access response from at least one of the first cell or a different second cell, the access response indicating that the second cell is to be accessed by the first device; and means for transmitting a second message to the second cell related to the second access to the second cell.

[0156] In an exemplary embodiment, the access response includes at least one of an identification of the second cell, an indication of a first resource for the first device to transmit the second message, an indication of an available time for the second cell, an indication of a beam for transmission of the second message, or an indication of a timing advance for transmission of the second message.

[0157] In some exemplary embodiments, the means for transmitting the second message comprises means for determining that the second cell is available based on an availability time of the second cell, and means for transmitting the second message to the second cell based on the determination that the second cell is available.

[0158] In some exemplary embodiments, the apparatus further comprises means for receiving, from the first cell via at least one of system information or radio resource control signaling, an identification of the second cell.

[0159] In some exemplary embodiments, the means for receiving the access response comprises means for monitoring a second resource associated with at least one of the first cell or the second cell to receive the access response.

[0160] In an exemplary embodiment, the second resources include resources associated with a second cell, and the apparatus further comprises means for receiving an indication of the resources associated with the second cell from at least one of the first cell or the second cell.

[0161] In some exemplary embodiments, the means for receiving an indication of resources associated with the second cell includes means for receiving an indication of resources associated with the second cell from the first cell via at least one of system information or radio resource control signaling.

[0162] In some exemplary embodiments, the means for receiving an indication of resources associated with the second cell comprises means for receiving an indication of resources associated with the second cell from the second cell via at least one of a synchronization signal block or system information.

[0163] In some exemplary embodiments, the means for transmitting the second message comprises means for transmitting the second message to the second cell using a beam, the beam including at least one of a beam used to transmit the first message to initiate first access to the first cell or a beam indicated by the access response.

[0164] In an exemplary embodiment, the apparatus further comprises means for detecting at least a synchronization signal block from the second cell prior to transmitting the second message.

[0165] In some exemplary embodiments, the means for detecting at least a synchronization signal block includes means for detecting a synchronization signal block and a system information block from the second cell.

[0166] In some exemplary embodiments, the second message includes at least one of message 3 in a first random access procedure for a first access to the first cell or message 1 in a second random access procedure for a second access to the second cell.

[0167] In some exemplary embodiments, the first cell comprises a coverage cell and the second cell comprises a capacity cell.

[0168] In some exemplary embodiments, an apparatus capable of performing method 500 (e.g., second device 210 as shown in FIG. 2 ) may comprise means for performing each step of method 500. The means may be implemented in any suitable form. For example, the means may be implemented in a circuit or a software module.

[0169] In some exemplary embodiments, an apparatus comprises means for receiving, in a first cell, a first message from a first device for initiating a first access to the first cell, and means for determining that a different second cell is to be accessed by the first device.

[0170] The apparatus in some demonstrative embodiments further comprises means for transmitting an access response from at least one of the first cell or a different second cell to the first device, the access response indicating that the second cell is to be accessed by the first device.

[0171] In some exemplary embodiments, the access response includes at least one of an identification of the second cell, an indication of a first resource for the first device to transmit a second message related to the second access to the second cell, an indication of an available time for the second cell, an indication of a beam for transmission of the second message, or an indication of a timing advance for transmission of the second message.

[0172] In some exemplary embodiments, the means for transmitting the access response comprises means for generating an access response and means for transmitting a random access response from the first cell to the first device.

[0173] In some exemplary embodiments, the second cell is in a sleep mode or an OFF mode, and the apparatus further comprises means for sending a request to a third device that serves the second cell to wake up the second cell.

[0174] In some exemplary embodiments, the apparatus further comprises means for transmitting, to a third device serving the second cell, an indication indicating that the second cell is accessed by the first device.

[0175] In some exemplary embodiments, the apparatus further comprises means for transmitting, to a third device serving the second cell, at least one of an identification of the first device, an indication of first resources for transmitting, by the first device, a second message related to a second access to the second cell, or an indication of a timing advance for transmission of the second message.

[0176] In some exemplary embodiments, the second message includes at least one of message 3 in a first random access procedure for a first access to the first cell or message 1 in a second random access procedure for a second access to the second cell.

[0177] In some exemplary embodiments, the apparatus further comprises means for receiving an access response from a third device serving the second cell, and the means for transmitting the access response transmits the access response from the second cell to the first device.

[0178] In some exemplary embodiments, the apparatus further comprises means for transmitting, to the third device, an indication of third resources for detecting the first message from the first device to initiate first access to the first cell.

[0179] In an exemplary embodiment, the apparatus further comprises means for transmitting, via at least one of system information or radio resource control signaling, to the first device, an indication of resources associated with the second cell and used to receive the access response.

[0180] In some exemplary embodiments, the apparatus further comprises means for transmitting, via at least one of system information or radio resource control signaling, an identification of the second cell to the first device.

[0181] In some exemplary embodiments, the means for determining is based on at least one of a load of the first and / or second cell, a traffic type requested by the first device, a location of the first device, or radio conditions associated with the first and / or second cell.

[0182] In some exemplary embodiments, the means for determining is in coordination with the second cell.

[0183] In some exemplary embodiments, the first cell comprises a coverage cell and the second cell comprises a capacity cell.

[0184] In some exemplary embodiments, an apparatus capable of performing method 600 (e.g., third device 215 as shown in FIG. 2) may comprise means for performing each step of method 600. The means may be embodied in any suitable form. For example, the means may be implemented in a circuit or a software module.

[0185] In some exemplary embodiments, an apparatus comprises means for determining that a second cell is accessed by a first device, where the first device initiates a first access to a different first cell, and means for detecting, based on the determination that the second cell is accessed by the first device, a second message related to a second access to the second cell from the first device.

[0186] In some exemplary embodiments, the means for determining that the second cell is accessed by the first device comprises means for receiving an indication from the second device that serves the first cell indicating that the second cell is accessed by the first device, and means for determining that the second cell is accessed by the first device based on the receipt of the indication.

[0187] In some exemplary embodiments, the second cell is in a sleep mode or an OFF mode, and the apparatus further comprises means for receiving a request from the second device to wake up the second cell, and means for waking up the second cell based on receiving the request.

[0188] In some exemplary embodiments, the apparatus further comprises means for broadcasting at least the synchronization signal block in the second cell.

[0189] In some exemplary embodiments, the means for broadcasting at least the synchronization signal block comprises means for broadcasting the synchronization signal block and means for broadcasting a system information block in the second cell.

[0190] In some demonstrative embodiments, the apparatus further comprises means for receiving, from the second device, at least one of an identification of the first device, an indication of a first resource for transmission of the second message by the first device, or an indication of a timing advance for transmission of the second message.

[0191] In some exemplary embodiments, the means for determining that the second cell is accessed by the first device comprises means for receiving from the second device an indication of a third resource for detecting a first message for initiating a first access to the first cell, means for detecting the first message from the first device using the third resource, and means for determining that the second cell is accessed by the first device based on the detection of the first message.

[0192] In some exemplary embodiments, the means for determining that the second cell is to be accessed by the first device comprises means for determining that the second cell is to be accessed pursuant to coordination with the first cell based on at least one of a load of the first and / or second cell, a traffic type requested by the first device, a location of the first device, or radio conditions associated with the first and / or second cell.

[0193] In some exemplary embodiments, the apparatus further comprises means for transmitting, at the second cell, an access response toward the first device based on a determination that the second cell is accessed by the first device, the access response indicating that the second cell is accessed by the first device.

[0194] In an exemplary embodiment, the access response includes at least one of an identification of the second cell, an indication of a first resource for the first device to transmit the second message, an indication of an available time for the second cell, an indication of a beam for transmission of the second message, or an indication of a timing advance for transmission of the second message.

[0195] In some exemplary embodiments, the apparatus further comprises means for transmitting, in the second cell, via at least one of a synchronization signal block or a system information block to the first device, an indication of resources associated with the second cell and used for receiving the access response.

[0196] In some exemplary embodiments, the means for transmitting an access response toward the first device comprises means for transmitting the access response for the first device toward a second device serving the first cell.

[0197] In some exemplary embodiments, the second message includes at least one of message 3 in a first random access procedure for a first access to the first cell or message 1 in a second random access procedure for a second access to the second cell.

[0198] In some exemplary embodiments, the first cell comprises a coverage cell and the second cell comprises a capacity cell.

[0199] 7 is a simplified block diagram of a device 700 suitable for practicing an exemplary embodiment of the present disclosure. The device 700 may be provided to implement a communications device such as the first device 310 or the second device 320 shown in FIG. 3. As shown, the device 700 includes one or more processors 710, one or more memories 720 coupled to the processors 710, and one or more communications modules 740 coupled to the processors 710.

[0200] The communication module 740 is for two-way communication. The communication module 740 has at least one antenna to facilitate communication. The communication interface may represent any interface necessary for communication with other network elements.

[0201] The processor 710 may be of any type suitable for a local technology network and may include, by way of non-limiting example, one or more of a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. The device 700 may have multiple processors, such as application-specific integrated circuit chips that are time-slaved to a clock that synchronizes a main processor.

[0202] The memory 720 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memory include, but are not limited to, read-only memory (ROM) 724, electrically programmable read-only memory (EPROM), flash memory, hard disks, compact disks (CDs), digital video disks (DVDs), and other magnetic and / or optical storage devices. Examples of volatile memory include, but are not limited to, random access memory (RAM) 722 and other volatile memories that do not persist through power-down periods.

[0203] The computer program 730 includes computer-executable instructions that are executed by the associated processor 710. The program 730 may be stored in a memory, for example, the ROM 724. The processor 710 can load the program 730 into the RAM 722 to perform any suitable operations and processes.

[0204] An exemplary embodiment of the present disclosure may be implemented by a program 730 such that the device 700 may execute any process of the present disclosure, as described with reference to Figures 1 to 6. An exemplary embodiment of the present disclosure may also be implemented by hardware or a combination of software and hardware.

[0205] In some exemplary embodiments, the program 730 may be included in a computer-readable medium, which may be included in the device 700 (such as in memory 720) or other storage accessible by the device 700. The computing device 700 may load the program 730 from the computer-readable medium into RAM 722 for execution. The computer-readable medium may include any type of tangible non-volatile storage, such as ROM, EPROM, flash memory, hard disk, CD, DVD, etc. Figure 8 shows an example of a computer-readable medium 800 in the form of a CD or DVD. The computer-readable medium 1200 has the program 730 stored thereon.

[0206] In general, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic, or any combination thereof. One aspect may be implemented in hardware, while another aspect may be implemented in firmware or software that may be executed by a controller, microprocessor, or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described using block diagrams, flowcharts, or some other graphical representations, it should be understood that the blocks, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, special purpose circuits or logic, general purpose hardware or a controller or other computing device, or some combination thereof, in non-limiting examples.

[0207] The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, that execute on a target real or virtual processor to perform methods 400-600 described above with reference to FIGS. 1-6. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split among program modules as desired in various embodiments. The machine-executable instructions of the program modules may be executed in local or distributed devices. In distributed devices, the program modules may be located in both local and remote storage media.

[0208] Program code for implementing the methods of the present disclosure can be written in any combination of one or more programming languages. These program codes can be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus, and when executed by the processor or controller, cause the specific functions / operations shown in the flowcharts and / or block diagrams to be performed. The program code can run entirely on the machine, partially on the machine, as a standalone software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0209] In the context of the present disclosure, computer program code or associated data may be carried by any suitable carrier to enable a device, computing device, or processor to perform the various processes and operations as described above. Examples of carriers include signals, computer-readable media, etc.

[0210] The computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. Computer-readable media include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. More specific examples of computer-readable storage media include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof.

[0211] Furthermore, although operations are depicted in a particular order, this should not be understood as requiring such operations to be performed in the particular order shown, or sequentially, or to perform all of the illustrated operations, to achieve desirable results. In certain situations, multitasking and parallel processing may be preferred. Similarly, while several specific implementation details are included in the above description, these should not be construed as limiting the scope of the disclosure, but rather as descriptions of features that may be unique to particular embodiments. Certain features that are described in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination.

[0212] Although the present disclosure has been described in language specific to structural features and / or methodological acts, it is to be understood that the present disclosure, as defined by the appended claims, is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. a first device at least one processor; When executed by the at least one processor, the first device is configured to: transmitting a first message to initiate a first access to a first cell; receiving an access response from at least one of the first cell or a different second cell, the access response indicating that the second cell is to be accessed by the first device; transmitting a second message to the second cell associated with a second access to the second cell; at least one memory storing instructions for executing the A first device comprising:

2. The access response an identification of the second cell; an indication of first resources for the first device to transmit the second message; an indication of the availability time of the second cell; an indication of a beam for the transmission of the second message; or an indication of a timing advance of the transmission of the second message; The first device of claim 1 , comprising at least one of:

3. Sending the second message comprises: determining that the second cell is available based on the available time of the second cell; transmitting the second message to the second cell upon determining that the second cell is available; and The first device of claim 2 , comprising:

4. The first device further comprises: receiving an identification of the second cell from the first cell via at least one of system information or radio resource control signaling; The first device according to claim 1 , wherein the first device executes the following:

5. receiving the access response monitoring a second resource associated with the at least one of the first cell or the second cell to receive the access response; 5. A first device according to claim 1, comprising:

6. The second resources include resources associated with the second cell, and the first device further receiving an indication of the resources associated with the second cell from at least one of the first cell or the second cell; 6. The first device of claim 5, adapted to execute:

7. Receiving the indication of the resources associated with the second cell comprises: receiving the indication of the resources associated with the second cell from the first cell via at least one of system information or radio resource control signaling; The first device of claim 6 , comprising:

8. Receiving the indication of the resources associated with the second cell comprises: receiving the indication of the resources associated with the second cell from the second cell via at least one of a synchronization signal block or system information; The first device of claim 6 , comprising:

9. Sending the second message comprises: a beam used to transmit the first message for initiating the first access to the first cell; or a beam indicated by the access response; transmitting the second message to the second cell using the beam including at least one of:

9. A first device according to claim 1, comprising:

10. The first device further comprises: detecting at least a synchronization signal block from the second cell before transmitting the second message; 10. A first device according to any preceding claim, adapted to execute:

11. Detecting at least the synchronization signal block comprises: detecting the synchronization signal block and the system information block from the second cell; The first device of claim 10, comprising:

12. The second message is Message 3 in a first random access procedure for the first access to the first cell, or message 1 in a second random access procedure for the second access to the second cell; 11. The first device according to claim 1, comprising at least one of:

13. 13. The first device of claim 1, wherein the first cell comprises a coverage cell and the second cell comprises a capacity cell.

14. a second device at least one processor; When executed by the at least one processor, the second device receives at least: receiving, at a first cell, a first message from a first device to initiate a first access to the first cell; determining a different second cell to be accessed by the first device; at least one memory storing instructions for executing the A second device comprising:

15. transmitting, to the first device, an access response from at least one of the first cell or another second cell, the access response indicating that the second cell is to be accessed by the first device; The second device of claim 14 further comprising:

16. The access response an identification of the second cell; an indication of first resources for the first device to transmit a second message associated with a second access to the second cell; an indication of the availability time of the second cell; an indication of a beam for the transmission of the second message; or an indication of a timing advance of the transmission of the second message; The second device of claim 15, comprising at least one of:

17. transmitting the access response generating the access response; transmitting the random access response from the first cell to the first device; 17. The second device of claim 15 or 16, comprising:

18. the second cell is in a sleep mode or an off mode, and the second device further comprises: sending a request to a third device serving the second cell to activate the second cell; 20. The second device of claim 17, adapted to execute:

19. The second device further comprises: sending an indication to a third device serving the second cell indicating that the second cell is accessed by the first device; 19. A second device according to any one of claims 14 to 18, adapted to execute:

20. The second device further comprises: an identification of the first device; an indication of first resources for the first device to transmit a second message associated with a second access to the second cell; or an indication of a timing advance of the transmission of the second message; to a third device serving the second cell; 20. A second device according to any one of claims 14 to 19, adapted to execute:

21. The second message is a message in a first random access procedure for the first access to the first cell, or message 1 in a second random access procedure for the second access to the second cell; 21. The second device of claim 16 or 20, comprising at least one of:

22. The second device further comprises: receiving the access response from a third device serving the second cell; and transmitting the access response transmitting an access response from the second cell to the first device; 17. The second device of claim 15 or 16, comprising:

23. The second device further comprises: sending, to the third device, an indication of third resources for detecting the first message from the first device to initiate the first access to the first cell; 23. The second device of claim 22, adapted to execute:

24. The second device further comprises: transmitting, via at least one of system information or radio resource control signaling, to the first device, an indication of resources associated with the second cell and to be used for receiving the access response; 24. A second device according to claim 22 or 23, adapted to execute:

25. The second device further comprises: transmitting an identification of the second cell to the first device via at least one of system information or radio resource control signaling; 25. A second device according to any one of claims 14 to 24, adapted to execute:

26. The determining step comprises: a load on the first and / or second cell; a traffic type requested by the first device; the location of the first device, or radio conditions associated with the first and / or second cells; 26. The second device according to claim 14, wherein the second device is implemented based on at least one of the following:

27. The second device of claim 26 , wherein the determining is performed pursuant to coordination with the second cell.

28. 28. The second device of claim 14, wherein the first cell comprises a coverage cell and the second cell comprises a capacity cell.

29. a third device, at least one processor; When executed by the at least one processor, the method causes at least the third device to: determining that a second cell served by the third device is accessed by a first device, and determining that the first device has initiated a first access to a different first cell; detecting, based on a determination that the second cell is accessed by the first device, a second message associated with a second access to the second cell from the first device; at least one memory storing instructions for executing the A third device comprising:

30. Determining that the second cell is accessed by the first device comprises: receiving an indication from a second device serving the first cell that the second cell is accessed by the first device; determining, based on the reception of the indication, that the second cell is to be accessed by the first device; 30. The third device of claim 29, comprising:

31. The second cell is in a sleep mode or an off mode, and the third device further comprises: receiving a request from the second device to activate the second cell; activating the second cell based on the receiving of the request; 31. The third device of claim 30, adapted to perform:

32. The third device further comprises: broadcasting at least a synchronization signal block in the second cell; 32. The third device of claim 31, adapted to perform:

33. broadcasting at least the synchronization signal block broadcasting the synchronization signal block and the system information block to the second cell; 33. The third device of claim 32, comprising:

34. the third device further comprising: From the second device: an identification of the first device; an indication of first resources for the first device to transmit the second message; or an indication of a timing advance for transmission of said second message; 34. A third device according to any of claims 30 to 33, adapted to receive at least one of:

35. Determining that the second cell is accessed by the first device comprises: receiving, from the second device, an indication of third resources for detecting a first message from the first device to initiate the first access to the first cell; Detecting the first message from the first device using the third resource; and determining, based on the detection of the first message, that the second cell is accessed by a first device; 30. The third device of claim 29, comprising:

36. Determining that the second cell is accessed by the first device comprises: a load on the first and / or second cell; a traffic type requested by the first device; the location of the first device, or radio conditions associated with the first and / or second cells; determining that the second cell is to be accessed in accordance with coordination with the first cell based on at least one of:

36. The third device of claim 35, comprising:

37. the third device further comprising: transmitting, at the second cell, an access response toward the first device based on a determination that the second cell is to be accessed by the first device, the access response indicating that the second cell is to be accessed by the first device; 37. A third device according to claim 35 or 36, adapted to perform:

38. The access response an identification of the second cell; an indication of first resources for the first device to transmit the second message; an indication of the availability time of the second cell; an indication of a beam for the transmission of the second message; or an indication of a timing advance of the transmission of the second message; 38. The third device of claim 37, comprising at least one of:

39. The third device further comprises: transmitting, in the second cell, via at least one of a synchronization signal block or a system information block to the first device, an indication of resources associated with the second cell and to be used for receiving the access response; 39. A third device according to claim 37 or 38, adapted to perform:

40. Transmitting the access response toward the first device includes: transmitting the access response to the first device to a second device serving the first cell; 39. A third device according to claim 37 or 38, comprising:

41. The second message is Message 3 in a first random access procedure for the first access to the first cell, or message 1 in a second random access procedure for the second access to the second cell; 41. A third device according to any one of claims 29 to 40, comprising at least one of:

42. 39. The third device of claim 27, wherein the first cell comprises a coverage cell and the second cell comprises a capacity cell.

43. In the first device, transmitting a first message to initiate a first access to a first cell; receiving an access response from at least one of the first cell or a different second cell, the access response indicating that the second cell is to be accessed by the first device; transmitting a second message to the second cell associated with a second access to the second cell; A method comprising:

44. In the second device, receiving, at a first cell, a first message from a first device to initiate a first access to the first cell; determining a different second cell to be accessed by the first device; A method comprising:

45. a third device serving the second cell; determining that the second cell is to be accessed by a first device, the first device initiating a first access to a different first cell; detecting, based on a determination that the second cell is accessed by the first device, a second message associated with a second access to the second cell from the first device; A method comprising:

46. means for transmitting a first message to initiate a first access to a first cell; means for receiving an access response from at least one of the first cell or a different second cell, the access response indicating that the second cell is to be accessed by a first device; and means for transmitting a second message to the second cell related to a second access to the second cell; An apparatus comprising:

47. means for receiving, in a first cell, from a first device, a first message for initiating a first access to the first cell; means for determining that a different second cell is accessed by the first device; An apparatus comprising:

48. means for determining that a second cell is to be accessed by a first device, the first device initiating a first access to a different first cell; means for detecting, based on a determination that the second cell is accessed by the first device, a second message associated with a second access to the second cell from the first device; An apparatus comprising:

49. A computer readable medium having stored thereon instructions for causing an apparatus to perform at least the method of any of claims 43 to 45.

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