JP6469750B2 - Layered mobility - Google Patents

Description

  Exemplary non-limiting embodiments of the present invention generally relate to wireless communication systems. In particular, embodiments of the present invention relate to an apparatus, method and computer program product in a communication network.

  The following description of the background art includes insight, discovery, understanding or disclosure, or association, along with disclosure provided by the present invention that was not known in the related art prior to the present invention. Certain such contributions of the invention will be specifically pointed out below, while other such contributions of the invention will be apparent from their context.

  Wireless communication systems are constantly under development. The system under development provides cost effective support with high data rates and resource utilization efficiency. One communication system under development is the Third Generation Partnership Project (3GPP) Long Term Evolution (LTE), also known as LTE-Advanced (LTE-A). LTE is configured to support various services such as high-speed data, multimedia unicast, and multimedia broadcast services.

  One aspect under development is the concept of small cells. It has been proposed to have a small cell layer or a large number of smaller cells with local area coverage under a macrocell serving a large area. Small cells can reduce the power consumption of base stations and user equipment (UE) and can be used to offload traffic from the macro cell layer to the small cell layer, and some new services in the future Make the format potentially possible.

  It has been proposed that the UE has dual connectivity to the macro cell layer and the small cell layer. Dual connectivity means a logical relationship between the UE and two different cell layers. Either the UE has a physical link established simultaneously to the macro cell and the small cell layer, or the UE switches physical resources in time, or the UE switches its logical macro connection through the small cell. Let it run. Cooperative transmission in the small cell layer is not excluded.

  According to an aspect of the invention, an apparatus according to claim 1 is provided.

  According to an aspect of the present invention, an apparatus according to claim 6 is provided.

  According to an aspect of the present invention, an apparatus according to claim 10 is provided.

  According to an aspect of the present invention there is provided a method according to claim 11.

  According to an aspect of the present invention there is provided a method according to claim 16.

  According to an aspect of the present invention, a method according to claim 20 is provided.

  Embodiments of the invention are defined in the dependent claims.

  Embodiments of the present invention will now be described in detail by way of example with reference to the accompanying drawings.

An example of a communication environment is shown. It is a flowchart which shows embodiment of this invention. It is a flowchart which shows embodiment of this invention. It is a flowchart which shows embodiment of this invention. An example of the apparatus which applies embodiment of this invention is shown. An example of the apparatus which applies embodiment of this invention is shown. It is a signaling chart which shows embodiment of this invention.

  The following embodiments are merely examples. The terms “one”, “one” or “several” embodiments appear in numerous places in the specification, but this does not necessarily mean that each refers to the same embodiment or has one feature. It is not meant to be applied only to the embodiment. Other embodiments can also be configured by combining one feature of different embodiments. Further, the words “comprising” and “including” are not intended to limit the embodiments described herein to the embodiments described herein, and such embodiments are not limited to such embodiments. It should be understood that features, structures, units, modules, etc. not specifically described herein may also be included.

  These embodiments can be applied to any base station, network element, user equipment (UE), server, corresponding component, and / or communication system, or a combination of different communication systems that support the required functionality.

  Protocols used, communication system specifications, servers and user terminals are being developed rapidly, especially in wireless communication. Such development requires extra changes to the embodiments. Accordingly, all terms and expressions are to be interpreted broadly and are illustrative of the embodiments and not limiting.

  There are a number of different wireless protocols that should be used in a communication system. Some examples of different communication systems are Universal Mobile Telecommunications System (UMTS) Radio Access Network (UTRAN or E-UTRAN), Long Term Evolution (also known as LTE®, E-UTRA), Long Term Evolution Advanced (LTE-A (registered trademark)), IEEE 802.11 standard, Wireless Local Area Network (WLAN) based on World Wide Interoperability (WiMAX) for microwave access, Bluetooth (registered trademark), personal communication A system that uses service (PCS) and ultra-wideband (UWB) technology. IEEE refers to the Institute of Electrical and Electronics Engineers. LTE and LTE-A were developed by the 3rd Generation Partnership Project 3GPP.

  FIG. 1 is a simplified diagram of a communication environment showing only some elements and functional entities, all of which are logical units that may differ in implementation from those shown. The connections shown in FIG. 1 are logical connections, and the actual physical connections may be different. Those skilled in the art will appreciate that the system also includes other functions and structures. It is clear that the functions, structures, elements and protocols used in or for communication are not relevant to the actual invention. Therefore, they need not be described in detail here.

  In the example of FIG. 1, a wireless system based on LTE / SAE (Long Term Evolution / System Architecture Evolution) network elements is shown. However, the embodiments described in these examples are not limited to LTE / SAE radio systems and can be implemented in other radio systems.

  A simple example of the network of FIG. 1 includes an SAE gateway (GW) 100 and an MME 102. The SAE gateway 100 provides a connection to the Internet (NET) 104. FIG. 1 shows a base station or eNodeB 106 serving a cell 108. In this example, the eNodeB 106 is connected to the SAE gateway 100 and the MME 102. Also in this example, cell 108 is a macro cell and eNodeB 106 is a macro cell node. Macro node 106 is shown as a macro eNodeB (MeNB).

  In general, an eNodeB (enhanced Node B) of a communication system hosts radio resource management functions, that is, radio bearer control, radio admission control, connection mobility control, and dynamic resource allocation (scheduling). The MME 102 (Mobility Management Entity) is responsible for overall control of the UE for mobility, session / call and state management with the help of the eNodeB when the UE connects to the network. SAE GW 100 is an entity configured to act as a gateway between a network and other parts of a communication network such as the Internet. The SAE GW may be a combination of two gateways: a serving gateway (S-GW) and a packet data network gateway (P-GW).

  The eNodeB 106 provides radio coverage to the cell 108. Cell 108 may be of any size or form based on the antenna system utilized. The eNodeB 106 controls the cellular radio communication link established between the eNodeB 106 and a terminal device or user equipment (UE) located in the cell 108. A terminal device is a user device of a cellular communication system, such as a personal computer (PC), laptop, handheld computer, tablet, mobile phone, or other user terminal or user device that can communicate with a cellular communication network.

  In the example of FIG. 1, a set of small cells is installed in a macro cell. Each small cell is served by a node. For example, small cells 112, 114, 116 serviced by nodes 118, 120, and 122 are shown. Nodes 118, 120, 122 serving small cells are shown as local area base stations or eNodeBs (LAeNBs) and they form a small cell layer or small cell cluster. In practice, the number of small cells is significantly greater than three. The small cells are connected to each other using, for example, an X2 interface. There is also an interface between the macro eNodeB and the small cell eNodeB. In some practical deployments, this interface will be subject to interface implementation technology, limited capacity of the interface, link reliability characteristics obtained by introducing an error correction protocol over the transport link, or link capacity during high activity hours. Due to the traffic characteristics that make it unsatisfactory but sufficient during the silent time, it is not close to an ideal interface (eg optical), but an interface with significant delay. Delivery of packet traffic over such an interface will face queuing, delay, and delay changes.

  In one embodiment, the small cells operate in a separate frequency layer 126 dedicated to small cell deployments. Operation in the small cell frequency layer is controlled by an overlying macrocell that provides coverage in another frequency layer across the small cell coverage area. The control relationship between the macrocell layer and the small cell layer varies based on the architecture selected. In one embodiment, the macro layer provides common control information for UEs operating in the small cell layer.

  In one embodiment, the small cell operates in the same frequency layer 124 as the overlying macrocell. This is conceivable, for example, when building loss gives sufficient separation or when some coordinate mechanism is applied.

  One problem with small cells is related to mobility, i.e., to achieve handover and serving cell switching in the small cell layer so that it can be implemented without significant impact on the macro cell layer or the core network interface. These problems are significant when the number or density of small cells is high in macro coverage. These problems also become serious when the macro cell eNodeB cannot instantaneously control the small cell mobility due to a large delay between communications between the macro eNodeB and the small cell eNodeB. Frequent small cell switching problems enhance dynamic characteristics, dynamically manage resources, and scale network interfaces. Furthermore, the legacy handover procedure is voluminous and unnecessarily slow for frequent small cell switching, especially when the communication delay between the macro eNodeB and the small cell eNodeB is significant. In particular, the small cell layer in a limited set of small cells has an opportunity to share information at a high speed between small cells as compared to information sharing between macro cells and small cells, for example. Many relaxants can be applied to the moving function of small cells.

  In one embodiment, layered mobility is proposed for situations where the UE has dual connectivity to the macro cell layer and the small cell layer. Small cell mobility is handled independently of macro cell mobility. Macrocells control UE and macrolayer mobility, while small cell mobility without specific macrocell control is limited to a set of small cells or small cell clusters.

  The macro cell controls the UE to have the access layer context of the UE, the evolved packet system EPS context, and the stored security context. The macro cell plays the role of EPS bearer management with the UE's EPS connectivity, core network interface, and evolved packet core (EPC). Small cells are managed together if they form a defined domain, range and / or service set (eg, similar to a Wi-Fi service set).

  The management of the small cell configuration is realized by a macro eNodeB (MeNB) or by the small cell itself or by a network management entity. The first serving small cell of the cluster for the UE may be configured separately from the small cell neighbor cell configuration or, if the definition of the neighbor cell is clear, the small cell neighbor cell configuration is the serving small cell Can be added to the configuration. These configurations set the UE from single connectivity to dual connectivity, where single connectivity has one serving cell, either macro or small cell, while dual connectivity Has serving macrocells and serving small cells that have different functional roles for the served UE.

  Apart from the macro network context, the UE's local small cell context is generated by the MeNB or by the small cell cluster after the UE has small cell connectivity to the first serving small cell. The small cell UE context is defined by the first (original) serving small cell, which distributes the UE context to one or more identified small cell neighbors in the cluster when needed. To do. Alternatively, the small cell UE context is generated by a small cell management procedure (possibly including a small cell management function) in a small cell network or managed by the MeNB.

  In one embodiment, individual cell specific radio network temporary identifiers (c-RNTIs) for different cell layers are used. The macro cell c-RNTI behaves in a legacy way where the identifier changes when the serving cell changes. In the small cell layer, the c-RNTI need not change when the serving small cell changes.

  A cell specific radio network temporary identifier (c-RNTI) is specified by the MeNB for a UE served by a single macro cell. The c-RNTI changes when the serving macro cell changes due to the legacy handover procedure.

  The individual c-RNTI identification provided for small cell cluster UE operation is denoted as small cell c-RNTI (sc-RNTI). The UE can receive its small cell resource assignment by sc-RNTI, which is distinguished from legacy c-RNTI operation in that the sc-RNTI does not need to change during serving small cell changes. By keeping the sc-RNTI across small cell changes, the UE can initiate cell changes and the UE can easily know about sc-RNTIs that are valid for using resource allocation in the target cell. In small cell deployments, the consumption of identity space per small cell is probably low per cell due to the small cell size (and because of the small number of served UEs per cell), but large identity over the unit area. Space is needed. As an example, a single small cell does not require the 16 bit space (with an identity of 65,000 or more) reserved by the macro cell for the served UE, but a set of small cells for the served UE. Identity space of the same size (65000) can be reserved for use, which fundamentally increases the available identities per unit area compared to macro cells.

From time to time, the UE's sc-RNTI must be changed, for example, before the UE enters a small cell where the initially specified sc-RNTI is not valid (or free). This is handled by individual sc-RNTI change information included in the RRC message. This procedure is beneficial in that it does not need to be performed during small cell handover and can be performed while the UE is serviced in the small cell. An example of an sc-RNTI change information element is shown below.

sc-RNTI-Change {
old sc-RNTI
new sc-RNTI
SFN
}

  SFN represents the system frame number, and the new sc-RNTI SFN is enabled and the old sc-RNTI is disabled in the current serving cell.

  Another works without the SFN number, but changes the signaled old sc-RNTI to the new sc-RNTI, which changes when the small cell eNB receives the sc-RNTI-Change Response from the UE. It becomes effective. The time of change relates to a subframe index at the time of affirmation confirmation of reception of sc-RNTI-ChangeResponse by eNB from UE (three-way handshake). The timing relationship of the RRC message, its confirmation, and receipt of confirmation are known.

  The UE receives the sc-RNTI for operation in the small cell cluster when establishing a connection to the small cell layer under the MeNB. In one embodiment, sc-RNTI is signaled to the UE by the MeNB. In another embodiment, c-RNTI is determined and matched in the small cell and signaled to the UE by the serving small cell. There are various ways to match sc-RNTI. The sc-RNTI is determined by the small cell support node, access controller, or other similar network node. Also, the identity is determined by the serving small cell and propagated to small cell neighbors in the small cell cluster, for example, via a connected X2 interface. The identity is also carried to the small cell by the control MeNB. In one embodiment, the small cells are connected as a local cloud, which can manage identity shares within the cloud.

  In one embodiment, handover within a small cell cluster is achieved with a more rational implementation than a conventional RACH (Random Access Channel) procedure. A UE wishing to hand over sends a candidate target cell list to the serving small cell. The serving small cell is configured to send a response permitting or denying the UE access to one or more of the target cells in the preferred priority order of the network. Rejection is used to control mobility across small cell clusters. The UE accesses the target cell selected from the allowed set by using dedicated scheduling request SR resources defined in the set of small cells. SR resources are defined using radio resource control RRC signaling. In conventional solutions, SR resources are defined only in the serving cell.

  In one embodiment, the scheduling request SR uses dedicated physical uplink control channel PUCCH format 1 / 1a / 1b resources allocated by the source cell without requiring handover specific signaling with the target cell (and thus This is different from conventional PRACH (physical random access channel) preamble allocation).

  In one embodiment, cell-specific pre-allocation of cell access SR resources is used. The cell access SR resource is separated from the serving cell SR resource. In this embodiment, the network defines a set of PUCCH formats 1 for SR-based cell access for each neighboring cell in the small cell cluster area in each cell. In other words, in the case of a handover, the source cell has a set of pre-assigned PUCCH format 1 resources for each neighboring target cell candidate. The source cell can then allocate SR signaling resources to the UE from a dedicated PUCCH format 1 resource that forms a set of pre-allocated resources in this target cell. Also, the allocation to the UE is temporary and remains valid as long as it expires after a predetermined time or remains in a state where the UE is served by the same resource. If the UE switches the serving cell, it will of course obtain an updated designation belonging to the source cell to the new neighboring target cell. As described above, the UE has different cell access resources for different target cell candidates in neighboring cells.

  A UE that has measured and selected a preferred and allowed target cell knows in advance what the dedicated SR signal it generates to access the target cell. The PUCCH format 1 assigned for cell access follows the normal PUCCH format 1 configuration, ie the base sequence and repeated shift hopping are determined according to the target cell physical cell identity (PCI). Alternatively, the base sequence and repetitive shift hopping can be derived based on virtual PCI signaled to the UE by RRC signaling. Therefore, virtual PCI is particularly used for visited cell access. The UE is configured to receive a virtual PCI for access of the target cell. Alternatively, the UE uses the PCI value of its current serving source cell as the designated virtual PCI value in the target cell. Therefore, virtual PCI is common for UEs accessing the target cell from the same source cell and different for UEs accessing the target cell from another source cell. The virtual PCI list used to access neighboring cells in the small cell cluster is advertised to the UE by dedicated signaling from the serving source cell. The UE needs this information only if the visited PCI designation becomes obvious and is valid for the small cell cluster, and a list of updates is given as it becomes available. Using the source cell's PCI as the target cell's virtual PCI is the simplest solution and does not increase interference if the time and frequency of cell access resources and serving cell resources in neighboring cells are different. Interference can also be reduced if the virtual PCI designation is obvious and given from values outside the PCI within the small cell cluster.

  In one embodiment, UE specific allocation of cell access SR resources is used. In this embodiment, the UE allocates dedicated cell access SR resources in each cell in the small cell cluster. As the cell access SR resource, either the above-described PCI or virtual PCI can be used. When establishing a connection to the small cell layer under the MeNB, the UE receives sc-RNTI and a set of dedicated SR definitions to operate in the small cell cluster. In one embodiment, the UE is configured to store information regarding predetermined user equipment specific cell access resources for each cell. For sc-RNTI management, a similar mechanism for managing dedicated SR resources can be used.

In one embodiment, the parameters for cell access SR resources are as follows:
{
Target cell parameters {
Target cell identity (PCI)
Virtual-PCI for the cell access
}

UE-specific parameters {
Virtual PCI for the cell access [unless this is given by the target cell parameters or derived from the source cell PCI]
Visited-PUCCH resource index [used in defining PRB, OCC and cyclic shift]
Visited-PUCCH config index [defining periodicity and subframe offset]
}

  The information element is provided for the UE by dedicated signaling for a single target cell, a set of target cells, or a cluster of target cells. In the case of signaling for multiple cells, the information element is repeated for each of the target cells. Alternatively, the PUCCH common configuration can be included in the target cell parameters.

  For optimization, the target cell parameters are commonly advertised to the UE by RRC signaling, and the UE may request information on the visited resources of the target cell. In this case, the UE knows the virtual PCI per target cell and the visited PUCCH resources per target cell and obtains UE specific parameters for the specific target cell.

  The SR multiplexing capacity of the PUCCH resource is large. This is because in a small cell environment, there is no wide delay spread or large delay difference for the UE being accessed. For this reason, it is possible to use repetitive shifts with high density, and therefore repetitive shifts per second allow 36 SR signals per physical resource block PRB.

  In small cells, the PUCCH capacity is large. This is because the bandwidth is typically large, the number of UEs per small cell is small, and thus configuring more PUCCH resources is not as bad a control overhead as a large cell that can be fully loaded. Because there is no. Reserving PUCCH resources from partially loaded cells does not have a negative impact. This is because resources are available (in any case idle) and unused PUCCH reserved for use does not cause interference.

  2, 3 and 4 are flowcharts illustrating embodiments of the present invention. These flowcharts relate to the implementation of small cell handover (HO). FIG. 2 shows an example of the operation of the UE, FIG. 3 shows the operation of the source small cell, and FIG. 4 shows the operation of the target small cell.

  In FIG. 2, the UE receives measurement configuration or guidance and event triggers from the network in step 202. This information is related to the small cell configuration. The UE has a separate connection with a macro cell having a first identity, i.e. c-RNTI associated with the macro cell connection. In one embodiment, a second identity, sc-RNTI, is associated with the small cell connection.

  In step 204, the UE takes measurements and determines a preference list of candidate target cells or a set of target small cells.

  In step 206, the UE informs the current serving small cell of a candidate target cell or a list of target cell preferences.

  In step 208, the UE receives a response representing the authorized or preferred target cell with the small cell. If rejected, the procedure ends (210). The serving small cell denies access to some of the UE's preferred target cells.

  In step 212, the UE receives permission or preference from the small cell and the UE is configured to select a target cell. The serving small cell sends a response to a request that allows the UE to access one or more of the target cells in the preferred priority order of the network. This response includes an SR resource assignment for a given target cell. The UE may select a target cell from the list of allowed target cells.

  In step 214, the UE attempts a small cell handover by sending a scheduling request to the target small cell using the given SR resource.

  FIG. 3 shows an example of the operation of a source small cell during a small cell handover.

  In step 302, the small cell (SCeNB) defines a measurement configuration or measurement guidance and event triggers for UE operation in the small cell (other than those applicable to the macro cell layer).

  In step 304, the SC eNB defines neighboring small cell access resources PUCCH, SR that are UE specific or target cell specific.

  In step 306, the SC eNB receives a request from the UE to access the target cell for handover.

  In step 308, the SC eNB responds to the UE to allow or deny access requests to the target cell for handover.

  In one embodiment, access rejection is based on network knowledge of target small cells that do not belong to the small cell cluster, eg, target small cells that do not have a network interface to the serving MeNB. Other rejections are based on serving small cells where the feasibility of target candidates cannot be verified, or based on target cell load between small cells, for example based on normal or event-based load reports . The reason for refusal is included in the response.

  For some reason (the target small cell does not belong to the small cell cluster and the target cell access resource is not known), the rejection maintains sc-RNTI (and uses SR transmission to that target cell) This means that the small cell HO method cannot be used by the UE but can trigger a normal LTE HO process based on, for example, random access. In other words, this embodiment gives the MeNB a way to control handovers between small cell clusters and makes the SCeNB dominant in handovers within small cell clusters. One small cell cluster can include all small cells in a connection to the same MeNB.

Example of small cell switching request and response:
Small cell change request {
List of target cells [physical cell identity, order in the UE preference list]
}
Small cell change response {
List of target cell [physical cell identity, order in the eNodeB preference list, allow / deny, reason (), access resource indication]
}

  The SC eNB is configured to redefine configuration and access resources as needed.

  FIG. 4 shows the operation of the target small cell during small cell handover.

  In step 400, the small cell (SCeNB) configures access resources such as PUCCH, SR for the UE to perform handover to this target cell. These access resources are separated from other resources such as serving cell PUCCH or random access resources.

  In step 402, the SC eNB is configured to scan for access requests (scheduling requests) from the UE on these access resources.

  If not found in step 404, the process continues to step 402.

  If found in step 404, the SC eNB is configured to allow or deny access.

  In case of rejection, the SC eNB is configured to send a negative response to the UE in step 408.

  If so, the SCeNB is configured to send an acknowledgment to the UE in step 410. The SC eNB responds with an uplink assignment using the sc-RNTI of the embodiment of the present invention.

  In step 412, the SC eNB is configured to communicate with the UE and allocates resources using sc-RNTI. The UE is configured to use serving cell resources instead of target cell access resources. The sc-RNTI configures or reconfigures serving cell resources for the UE, eg, SR and PUCCH resources. This is necessary if these resources have not yet been signaled from the source SCeNB to the UE.

  The procedure described above for small cell selection is not a forward handover in the sense that the UE is not allowed to automatically select a target cell, but only from a list of network-approved target cells. If the UE has to perform a handover to a target cell that is not allowed, the UE may use a MeNB procedure or a random access procedure. These result in significantly longer handover delays and more signaling over air and network interfaces (X2 and MeNB / SCeNB interfaces) compared to handover to dedicated access resources according to embodiments of the present invention.

  In one embodiment, the scheduling request SR mechanism is network controlled. This is because the UE only performs SR-based access to the target cell when the dedicated SR resource is enabled. For example, the scheduling request signal for the target cell access resource to the visited PUCCH resource is separated from UEs accessing from different neighboring cells by different virtual cell identities, which generates pseudo-random behavior for repetitive shift selection . In other words, UEs that access the target cell from different neighboring source cells use different sequence groups or sequence group hopping patterns and different repeated shift hopping. SR signals for UEs accessing a common target cell from the same source cell inherently use different PUCCH resource indices (eg, repetitive shifts). This is because the indices are already aligned by the source cell (source cell operation) and are therefore separated in the orthogonal direction by different iteration shifts. Furthermore, these signals are separated in the target cell by an orthogonal cover code OCC and / or PUCCH physical resource block PRB index from a UE accessing this same target cell from another source cell.

  As described above, UEs that access the target cell from different neighboring cells use SR transmission resources that are not orthogonal to each other. However, even if this is valid for resource reservation, the probability of actually using the SR signal for PUCCH PRB for handover purposes is that if all UEs in a set of neighboring cells have dedicated SR resources. Is quite low. Therefore, a closer multiplex configuration can be applied with a sufficiently high probability of SR detection.

  Signal separation for non-orthogonal SR transmission is provided by base sequence hopping that occurs according to a pattern derived from virtual PCI. Additional signal separation is provided by repetitive shift hopping that occurs according to a pattern derived from virtual PCI. Therefore, false detection of repetitive shifts used by individual UE accesses with different virtual PCIs is further reduced.

  The embodiment of the present invention is effective in signaling overhead and latency when switching small cells in the case of dual connectivity. A UE with a scheduling request sequence that can be easily used for access of a target cell of a small cell cluster is a non-contention-based UE to any target cell without any preparatory action other than requesting authorization from the source cell. Allow access to be made. This omits the RACH procedure in cell switching and eliminates the need for the source cell to allow a new c-RNTI by acquiring from the target cell. If the UE reports only the target cell candidate without reporting the measurement result and determines the target cell by itself based on the measurement, a large number of frequent measurement reports are unnecessary. Allocation of RACH resources for handover purposes consumes a minimum of 6 PRBs per RACH opportunity, which corresponds to (6 * 36) 216 SR resources, or where closer repetitive shift mapping is applicable Corresponds to more (6 * 72 = 432). In addition, the RACH procedure has the disadvantage that there is a risk of collision unless a dedicated preamble reservation mechanism is used. However, dedicated preamble reservation requires dynamic signaling and management of dedicated preamble usage. This is because the RACH sequence family is small and therefore a dedicated preamble reservation cannot be kept long.

  These effects can be achieved in a small cell scenario with dual connectivity. This is because it does not mean switching to legacy macrocell mobility.

  FIG. 5 illustrates one embodiment. This figure is a simple diagram of an apparatus to which an embodiment of the present invention is applied. In some embodiments, the device is a base station or an eNodeB or a part of an eNodeB.

  It should be understood that this apparatus is depicted herein as an example illustrating certain embodiments. It will be apparent to those skilled in the art that the device may have other functions and / or structures and not all functions and structures described herein are required. Although this device is depicted as one entity, different modules and memories may be implemented with one or more physical or logical entities.

  The example device includes a control circuit 500 configured to control at least a portion of the operation of the device.

  This apparatus includes a memory 502 for storing data. Further, the memory stores software 504 that can be executed by the control circuit 500. The memory may be integrated into the control circuit.

  This device includes a transceiver 506. This transceiver is operatively connected to the control circuit 500. This is connected to an antenna structure 508 that includes one or more antenna elements or antennas.

  The software 504 comprises a computer program including program code means that causes the control circuit 500 of the device to control the transceiver 506.

  The apparatus further includes an interface 510 operatively connected to the control circuit 500. This interface connects the device to each other device, such as eNodeB, via the X2 interface or to the core network.

  This device is a local area base station connected to other corresponding devices forming a local area base station cluster.

  The control circuit 500 is configured to execute one or more applications. These applications are stored in the memory 502.

  In one embodiment, these applications have a connection with a user device that has a first identity associated with the connection; the device belongs to a cluster of local area base stations; and sends a scheduling request to another local area of the cluster. A request to send to a base station, including a list of target candidate base stations, received from the user equipment; determine one or more suitable target base stations from the list of target candidate base stations; send a scheduling request And sending a response to the request to the user equipment; the response includes one or more base stations in the list as authorized targets and is required for scheduling The is intended to include information on the resource to be transmitted to the second local area base station.

  In one embodiment, these applications receive a scheduling request from a user equipment that is connected to another local area base station that the device belongs to a cluster of local area base stations; Assign communication resources to the user device and initiate communication with the user device to associate a given identity with the connection with the user device.

  FIG. 6 illustrates one embodiment. This figure is a simple diagram of an apparatus to which an embodiment of the present invention is applied. In some embodiments, the device is a user device or part of a user device.

  It should be understood that this apparatus is depicted herein as an example illustrating certain embodiments. It will be apparent to those skilled in the art that the device may have other functions and / or structures and not all functions and structures described herein are required. Although this device is depicted as one entity, different modules and memories may be implemented with one or more physical or logical entities.

  The example apparatus includes a control circuit 600 configured to control at least a portion of the operation of the apparatus.

  This apparatus includes a memory 602 for storing data. Further, the memory stores software 604 that can be executed by the control circuit 600. The memory may be integrated into the control circuit.

  This device includes a transceiver 606. This transceiver is operatively connected to the control circuit 600. This is connected to an antenna structure 608 that includes one or more antenna elements or antennas.

  The software 604 comprises a computer program including program code means that causes the control circuit 600 of the device to control the transceiver 606.

  The apparatus further includes a user interface 610 operatively connected to the control circuit 600. This user interface includes, for example, a touch sensitive display, a keyboard, a microphone, and a speaker.

  The control circuit 600 is configured to execute one or more applications. These applications are stored in the memory 602.

  In one embodiment, the applications have a first connection with a base station where the device serves a macrocell and a second connection with a first local area base station belonging to a cluster of local area base stations. Having a first identity associated with the first connection and a second identity associated with the second connection; sending a scheduling request to a second local area base station belonging to the cluster; and second Communicate with the second local area base station after receiving a response from the second local area base station and associating the second identity with the connection with the second local area base station.

  FIG. 7 is a signaling chart showing an embodiment of the present invention. This figure shows an example of target cell access by dedicated signaling among UE, source cell and target cell.

  In step 700, the UE performs measurements and determines a preferred list of candidate target cells or a set of target small cells.

  The UE then sends a message 704 indicating the candidate target cell or a preferred list of target cells to the current serving small cell.

  Next, in step 704, a target cell access resource is determined. This resource includes visited PUCCH resource, RNTI and virtual PCI.

  There are various ways how the source cell forms these parameters. They are easily configured for cells in a small cell cluster, where all cells in the cluster know the parameters to use for all cells in the cluster (from the small cell configuration stage) or source Either the cell must seek from the target cell candidate a specific configuration to use for it (without a macro cell that is significantly slower than small cell negotiation), or the source cell can use this information, eg, local cell management software From local cloud, or local domain support nodes.

  The source cell sends a response 706 to the UE. This response includes the accepted target cell and resource indication. This message includes, for example, physical cell identity PCI, order in preferred list of eNBs, grant / reject, reason, SR access resource indication. The visited PUCCH resource, RNTI, virtual PCI are given in the target cell indication message unless they are otherwise known. In one embodiment, the visited PUCCH is known from the small cell configuration, the RNTI is known as an already signaled sc-RNTI valid in the small cell cluster, and the virtual PCI is derived from the source cell PCI.

  The UE sends a scheduling request 708 to the target small cell using the given resource.

  The target cell transmits an acknowledgment 710 in this example. The target cell responds with an uplink assignment using sc-RNTI.

  The steps and related functions shown in the above description and in the accompanying drawings are not in absolute time order, and some steps may be performed in a different order than given or simultaneously. Other functions can also be performed between steps or within steps. Some steps may be excluded or replaced with corresponding steps.

  A device or controller capable of performing the steps described above may be implemented as an electronic digital computer or as a circuit consisting of a working memory (RAM), a central processing unit (CPU) and a system clock. The CPU includes a set of registers, an arithmetic logic unit, and a controller. The controller or circuit is controlled by a sequence of program instructions transferred from the RAM to the CPU. The controller includes a number of microinstructions for basic operations. The implementation of microinstructions varies based on CPU design. Program instructions are encoded in a programming language that is a high level programming language such as C, Java, or a low level programming language such as a machine language or assembler. The electronic digital computer also has an operating system that provides system services to computer programs written with program instructions.

  The term “circuit” as used in this document refers to all of the following: (A) hardware-only circuit implementation, such as implementation with only analog and / or digital circuits, (b) a combination of circuit and software (and / or firmware), eg (as the case may be), (i) a processor Or (ii) a digital signal processor that works together to cause the device to perform various functions, a processor / software portion including software and memory, and (c) no software or firmware physically present A microprocessor or part of a microprocessor that requires software or firmware for operation.

  This definition of “circuit” applies to all uses of this term in this document. As a further example, the term “circuit” as used herein simply covers a processor (or multiple processors) or a portion of a processor and its associated software and / or firmware implementations. The term “circuit” also applies to, for example, a baseband integrated circuit or application processor integrated circuit for a mobile phone, or similar in a server, cellular network device, or another network device, when applied to a particular element. It also covers integrated circuits.

  One embodiment is a computer program implemented on a distribution medium, comprising a computer instruction configured to control and control the device to execute the embodiment when loaded on an electronic device. provide.

  A computer program is in source code form, object code form, or an intermediate form thereof, and is stored on a kind of carrier that is an entity or device capable of carrying the program. Such carriers include, for example, record media, computer memory, read only memory, and software distribution packages. Based on the processing power required, the computer program is executed on a single electronic digital computer or distributed among multiple computers.

  The apparatus may also be implemented as one or more integrated circuits, such as an application specific integrated circuit ASIC. Other hardware embodiments are also feasible, such as circuits made with discrete logic components. A hybrid of these different embodiments is also possible. When selecting an implementation method, those skilled in the art will consider, for example, the requirements set for the size and power consumption of the device, the required processing capacity, the production cost and the production volume.

  It will also be apparent to those skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.

100: SAE gateway (GW)
102: MME
104: Internet (NET)
106: eNodeB
108: Cell 110: User equipment (UE)
112, 114, 116: Small cells 118, 120, 122: Nodes 124, 126: Frequency layer 500: Control circuit 502: Memory 504: Software 506: Transceiver 508: Antenna structure 510: Interface

Claims (4)

At least one processor;
At least one memory containing computer program code;
The at least one memory and computer program code, together with the at least one processor, the apparatus comprises at least
Having a first connection with a base station serving a macrocell and a second connection with a first local area base station belonging to a cluster of local area base stations;
Having a first identity associated with the first connection and a second identity associated with the second connection;
Sending a scheduling request to a second local area base station belonging to the cluster ;
Communicating with the second local area base station after receiving a response from the second local area base station and associating the second identity with a connection with the second local area base station ; and
Transmitting second local area base station information relating to the second identity;
An apparatus configured to cause At least one processor;
At least one memory containing computer program code;
A base station apparatus comprising: the at least one memory and computer program code, together with the at least one processor, the apparatus comprising:
Belongs to a cluster of local area base stations;
Having a connection with a user equipment having a first identity associated with the connection;
Receiving from the user equipment a request to send a scheduling request to another local area base station of the cluster, including a list of target candidate base stations;
Determining one or more suitable target base stations from the list of candidate target base stations;
Determining resources for sending the scheduling request ;
Transmitting a response to the request to the user equipment that includes one or more base stations from the list as authorized targets ; and
Sending information about the first identity to other base stations of the cluster;
Base station device configured to cause Having a first connection with a base station serving a macrocell and a second connection with a first local area base station belonging to a cluster of local area base stations;
Having a first identity associated with the first connection and a second identity associated with the second connection;
Sending a scheduling request to a second local area base station belonging to the cluster ;
Communicating with the second local area base station after receiving a response from the second local area base station and associating the second identity with a connection with the second local area base station ; and
Transmitting second local area base station information relating to the second identity;
A method involving that. Belongs to a cluster of local area base stations;
Having a connection with a user equipment having a first identity associated with the connection;
Receiving from the user equipment a request to send a scheduling request to another local area base station of the cluster, including a list of target candidate base stations;
Determining one or more suitable target base stations from the list of candidate target base stations;
Determining resources for sending the scheduling request ;
Transmitting a response to the request to the user equipment that includes one or more base stations from the list as authorized targets ; and
Sending information about the first identity to other base stations of the cluster;
A method at a base station comprising:

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