Patent ID: 12207149

DETAILED DESCRIPTION

The present disclosure will now be described in detail hereinafter with reference to the accompanied drawings, which form a part of the present disclosure, and which show, by way of illustration, specific examples of embodiments. Please note that the present disclosure may, however, be embodied in a variety of different forms and, therefore, the covered or claimed subject matter is intended to be construed as not being limited to any of the embodiments to be set forth below.

Throughout the specification and claims, terms may have nuanced meanings suggested or implied in context beyond an explicitly stated meaning. Likewise, the phrase “in one embodiment” or “in some embodiments” as used herein does not necessarily refer to the same embodiment and the phrase “in another embodiment” or “in other embodiments” as used herein does not necessarily refer to a different embodiment. The phrase “in one implementation” or “in some implementations” as used herein does not necessarily refer to the same implementation and the phrase “in another implementation” or “in other implementations” as used herein does not necessarily refer to a different implementation. It is intended, for example, that claimed subject matter includes combinations of exemplary embodiments or implementations in whole or in part.

In general, terminology may be understood at least in part from usage in context. For example, terms, such as “and”, “or”, or “and/or,” as used herein may include a variety of meanings that may depend at least in part upon the context in which such terms are used. Typically, “or” if used to associate a list, such as A, B or C, is intended to mean A, B, and C, here used in the inclusive sense, as well as A, B or C, here used in the exclusive sense. In addition, the term “one or more” or “at least one” as used herein, depending at least in part upon context, may be used to describe any feature, structure, or characteristic in a singular sense or may be used to describe combinations of features, structures or characteristics in a plural sense. Similarly, terms, such as “a”, “an”, or “the”, again, may be understood to convey a singular usage or to convey a plural usage, depending at least in part upon context. In addition, the term “based on” or “determined by” may be understood as not necessarily intended to convey an exclusive set of factors and may, instead, allow for existence of additional factors not necessarily expressly described, again, depending at least in part on context.

Radio resource control (“RRC”) is a protocol layer between UE and the basestation at the IP level (Network Layer). There may be various Radio Resource Control (RRC) states, such as RRC connected (RRC_CONNECTED), RRC inactive (RRC_INACTIVE), and RRC idle (RRC_IDLE) state. RRC messages are transported via the Packet Data Convergence Protocol (“PDCP”). As described, UE can transmit data through a Random Access Channel (“RACH”) protocol scheme or a Configured Grant (“CG”) scheme. CG may be used to reduce the waste of periodically allocated resources by enabling multiple devices to share periodic resources. The basestation or node may assign CG resources to eliminate packet transmission delay and to increase a utilization ratio of allocated periodic radio resources. The CG scheme is merely one example of a protocol scheme for communications and other examples, including but not limited to RACH, are possible. The wireless communications described herein may be through radio access.

There may be a master node (“MN”) and one or more secondary nodes (“SN”). The MN may include a master cell group (“MCG”) and the SN may each include a secondary cell group (“SCG”). The MCG is the group of cells provided by the master node (“MN”) and the SCG is the group of cells provided by the secondary node (“SN”). The MCG may include a primary cell (“PCell”) and one or more secondary cells (“SCell”). The SCG may include a primary secondary cell (“PSCell”) and one or more secondary cells (“SCell”). Each primary cell may be connected with multiple secondary cells. The primary cells (PCell, PSCell) are the master cells of their respective groups (MCG, SCG, respectively) and may initiate initial access. The primary cells may be used for signaling and may be referred to as special cell (“spCell”) where spCell=PCell+PSCell. The mobility between cells described in these embodiments may be based on the PCell, PSCell, and/or SCell. However, as described, they may be referred to as a source cell and a target cell.

A user equipment (“UE”) device may move between nodes or cells in which case a handover or a change/addition operation may occur to improve network reliability for the UE as it moves. The movement may be from a source cell to a target cell based on a number of potential target cells that are referred to as candidates. The movement between cells may also include a number of target cells that are potential candidate cells. A conditional handover (“CHO”) and a conditional PSCell addition/change (“CPAC”) are described below. The CPAC may include a conditional PSCell change (“CPC”) and/or a conditional PSCell addition (“CPA”).

A conditional handover (“CHO”) can reduce handover interruption time and improve mobility reliability. A CHO is a handover that is executed by the UE when one or more execution conditions are met. The UE can evaluate the execution condition(s) upon receiving the CHO configuration, and can stop evaluating the execution condition(s) once the handover is triggered. The CHO configuration may include a candidate PCell configuration generated by a candidate target node and the corresponding execution condition(s) for that candidate cell.

A conditional PSCell addition/change (“CPAC”) may include the UE having a network configuration for initiating access to a candidate PSCell, either to consider whether the PSCell is suitable for SN addition or SN change including an intra-SN change. This consideration may be based on configured condition(s). The UE in the wireless network can operate in dual connectivity (“DC”), including intra-E-UTRA DC or Multi-Radio DC (“MR-DC”). In the example of intra-E-UTRA DC, both the MN and SN provide E-UTRA access. While in the example of MR-DC, one node may provide new radio (“NR”) access and the other one provides either E-UTRA or NR access.

As described below with respect toFIGS.1-6, a network provider may include a number of network nodes (i.e. basestations) for providing network access to a user equipment (“UE”) device. The network nodes are referred to as basestations in some embodiments.FIGS.4-6illustrate cell mobility in which the UE device moves between cells. Control signaling may be used to facilitate this mobility. Mobility may be referred to as handover (HO) or a handover process. Dual Active Protocol Stack (DAPS) handover may reduce mobility interruption. Power coordination and/or resource coordination may occur between a source cell and a target cell in DAPS HO. In the DAPS based handover procedure, the user equipment (UE) maintains simultaneous connection with the source cell and target cell until releasing the source cell after successful random access to the target cell.FIG.7illustrates one example of DAPS HO.

Specifically, the source node may generate the power/resource coordination parameters/configurations and transmits them to the target node during HO preparation. When there is a centralized unit (CU) split from a distributed unit (DU), the CU or DU may generate and/or transmit the parameters/configurations to the peer node. In addition, the target DU may need to know when to start/complete DAPS HO (e.g. for resource scheduling, disabling/enabling some features that can not be coexisted with DAPS HO, etc.).FIGS.9-12illustrate examples for the CU/DU communications for the DAPS HO.

FIG.1shows an example basestation102. The basestation may also be referred to as a wireless network node and may be the network nodes (e.g. master node (“MN”), secondary node (“SN”), and the source/target nodes) shown inFIGS.3A-7B. The basestation102may be further identified to as a nodeB (NB, e.g., an eNB or gNB) in a mobile telecommunications context. The example basestation may include radio Tx/Rx circuitry113to receive and transmit with user equipment (UEs)104. The basestation may also include network interface circuitry116to couple the basestation to the core network110, e.g., optical or wireline interconnects, Ethernet, and/or other data transmission mediums/protocols.

The basestation may also include system circuitry122. System circuitry122may include processor(s)124and/or memory126. Memory126may include operations128and control parameters130. Operations128may include instructions for execution on one or more of the processors124to support the functioning the basestation. For example, the operations may handle random access transmission requests from multiple UEs. The control parameters130may include parameters or support execution of the operations128. For example, control parameters may include network protocol settings, random access messaging format rules, bandwidth parameters, radio frequency mapping assignments, and/or other parameters.

FIG.2shows an example random access messaging environment200. In the random access messaging environment a UE104may communicate with a basestation102over a random access channel252. In this example, the UE104supports one or more Subscriber Identity Modules (SIMs), such as the SIM1202. Electrical and physical interface206connects SIM1202to the rest of the user equipment hardware, for example, through the system bus210.

The mobile device200includes communication interfaces212, system logic214, and a user interface218. The system logic214may include any combination of hardware, software, firmware, or other logic. The system logic214may be implemented, for example, with one or more systems on a chip (SoC), application specific integrated circuits (ASIC), discrete analog and digital circuits, and other circuitry. The system logic214is part of the implementation of any desired functionality in the UE104. In that regard, the system logic214may include logic that facilitates, as examples, decoding and playing music and video, e.g., MP3, MP4, MPEG, AVI, FLAC, AC3, or WAV decoding and playback; running applications; accepting user inputs; saving and retrieving application data; establishing, maintaining, and terminating cellular phone calls or data connections for, as one example, Internet connectivity; establishing, maintaining, and terminating wireless network connections, Bluetooth connections, or other connections; and displaying relevant information on the user interface218. The user interface218and the inputs228may include a graphical user interface, touch sensitive display, haptic feedback or other haptic output, voice or facial recognition inputs, buttons, switches, speakers and other user interface elements. Additional examples of the inputs228include microphones, video and still image cameras, temperature sensors, vibration sensors, rotation and orientation sensors, headset and microphone input/output jacks, Universal Serial Bus (USB) connectors, memory card slots, radiation sensors (e.g., IR sensors), and other types of inputs.

The system logic214may include one or more processors216and memories220. The memory220stores, for example, control instructions222that the processor216executes to carry out desired functionality for the UE104. The control parameters224provide and specify configuration and operating options for the control instructions222. The memory220may also store any BT, WiFi, 3G, 4G, 5G or other data226that the UE104will send, or has received, through the communication interfaces212. In various implementations, the system power may be supplied by a power storage device, such as a battery282

In the communication interfaces212, Radio Frequency (RF) transmit (Tx) and receive (Rx) circuitry230handles transmission and reception of signals through one or more antennas232. The communication interface212may include one or more transceivers. The transceivers may be wireless transceivers that include modulation/demodulation circuitry, digital to analog converters (DACs), shaping tables, analog to digital converters (ADCs), filters, waveform shapers, filters, pre-amplifiers, power amplifiers and/or other logic for transmitting and receiving through one or more antennas, or (for some devices) through a physical (e.g., wireline) medium.

The transmitted and received signals may adhere to any of a diverse array of formats, protocols, modulations (e.g., QPSK, 16-QAM, 64-QAM, or 256-QAM), frequency channels, bit rates, and encodings. As one specific example, the communication interfaces212may include transceivers that support transmission and reception under the 2G, 3G, BT, WiFi, Universal Mobile Telecommunications System (UMTS), High Speed Packet Access (HSPA)+, and 4G/Long Term Evolution (LTE) standards. The techniques described below, however, are applicable to other wireless communications technologies whether arising from the 3rd Generation Partnership Project (3GPP), GSM Association, 3GPP2, IEEE, or other partnerships or standards bodies.

Multiple RAN nodes of the same or different radio access technology (“RAT”) (e.g. eNB, gNB) can be deployed in the same or different frequency carriers in certain geographic areas, and they can inter-work with each other via a dual connectivity operation to provide joint communication services for the same target UE(s). The multi-RAT dual connectivity (“MR-DC”) architecture may have non-co-located master node (“MN”) and secondary node (“SN”). Access Mobility Function (“AMF”) and Session Management Function (“SMF”) may the control plane entities and User Plane Function (“UPF”) is the user plane entity in new radio (“NR”) or 5GC. The signaling connection between AMF/SMF and the master node (“MN”) may be a Next Generation-Control Plane (“NG-C”)/MN interface. The signaling connection between MN and SN may an Xn-Control Plane (“Xn-C”) interface. The signaling connection between MN and UE is a Uu-Control Plane (“Uu-C”) RRC interface. All these connections manage the configuration and operation of MR-DC. The user plane connection between User Plane Function (“UPF”) and MN may be NG-U (MN) interface instance.

FIG.3shows a network architecture of a basestation Central Unit (CU) and basestation Distributed Unit (DU).FIG.3illustrates basestations (labeled as “gNB”) that communicate with an overall network (labeled (“5GC”). Basestations can communicate with one another via a control plane interface (“Xn-C”). One basestation is shown as have one CU that is connected to two DUs via an F1 interface. This is merely one example of an arrangement of a basestation. In some embodiments, there may be one or any number of DUs connected with a single CU.

The basestation can be divided into two physical entities named Centralized Unit (“CU”) and Distributed Unit (“DU”). Generally, the CU may provide support for the higher layers of the protocol stack such as SDAP, PDCP and RRC while the DU provides support for the lower layers of the protocol stack such as RLC, MAC and Physical layer. The CU may include operations for a transfer of user data, mobility control, radio access network sharing, session management, etc., except those functions allocated exclusively to the DU. The DU(s) are logical node(s) with a subset of the basestation functions, and may be controlled by the CU.

The CU may be a logical node hosting RRC, SDAP and PDCP protocols of the basestation or RRC and PDCP protocols of the basestation that controls the operation of one or more DUs. The DU may be a logical node hosting RLC, MAC and PHY layers of the basestation, and its operation may be at least partly controlled by the CU. A single DU may support one or multiple cells. However, each cell is only supported by a single DU. Each basestation may support many cells. As described in the embodiments herein, the cell mobility between cells may be from different CUs or DUs or may be internal to the CU and/or the DU.

The inter-cell mobility described herein may occur in a number of different examples. There may be intra-DU mobility where a UE changes cells within a single DU. Examples of intra-DU mobility include: 1) PCell change within one DU (may also include PCell change with SCell change); 2) PSCell change within one DU (may also include PSCell change with SCell change); and 3) PCell change within one DU with PSCell change within one DU (may also include SCell change within one cell group). In another mobility embodiment, there may be intra-CU and inter-DU mobility where a UE changes cells between different DUs but within a single CU. Examples of intra-CU and inter-DU mobility include: 1) PCell change across DU but within one CU (may also include PCell change with SCell change); and 2) PSCell change across DU but within one CU (may also include PSCell change with SCell change). In another mobility embodiment, there may be inter-CU mobility where a UE changes cells between different CUs. Examples of inter-CU mobility include: 1) PCell change across CU (may also include PCell change with SCell change); and 2) PSCell change across CU (may also include PSCell change with SCell change). In another embodiment, there may be a SCell change/addition and this example may include the SCell addition/change within one cell group.FIGS.4-6illustrate embodiments of UE mobility between cells.

FIG.4shows an embodiment of user equipment (UE) intra-DU mobility. The basestation may include a CU and at least one DU. In this embodiment, there is a single DU shown that has multiple cells. Both Cell 1 and Cell 2 are from the single DU. In this example, the UE402can move from Cell 1 to Cell 2 and is depicted inFIG.4with a UE trajectory from Cell 1 to Cell 2. The mobility from cells may occur when the UE402is in a position between the two cells and making its way to the third position within Cell 2. This is intra-DU mobility because the UE is moving cells within a single DU.

FIG.5shows an embodiment of user equipment (UE) intra-CU and inter-DU mobility. In this embodiment, the basestation may include a CU and two DUs (DU_1 and DU_2). Although each DU may have multiple cells, for this example each DU is shown providing a single cell such that DU_1 is providing Cell 1 and DU_2 is providing Cell 2. In this example, the UE502can move from Cell 1 to Cell 2 and is depicted inFIG.5with a UE trajectory from Cell 1 to Cell 2 which also results in a transition from DU_1 to DU_2. The mobility from cells may occur when the UE402is in a position between the two cells and making its way to the third position within Cell 2. This is intra-CU mobility because the UE is moving cells within a single CU. However, this is also inter-DU mobility because the UE is moving between different DUs.

FIG.6shows an embodiment of user equipment (UE) inter-CU mobility. In this embodiment, the basestation may include multiple CUs (CU_1 and CU_2). Each CU may include multiple DUs, but in this example, each CU is shown as having one corresponding DU (CU_1 has DU_1 and CU_2 has DU_2). Each of the DUs is shown with multiple cells. In this example, the UE trajectory of the UE602passes from Cell_2 to Cell_3 to an inter-CU position604(between CU_1 and CU_2) to Cell_5 and Cell_6. As the UE moves, the mobility may change cells as shown and may transition between a number of cells. Because the UE602(at the inter-CU position604) switches cells from CU_1 to CU_2, this transition is referred to as inter-CU mobility.

DAPS Handover

Dual Active Protocol Stack (DAPS) handover (HO) is one example of a HO type without interruption. The embodiments described herein can apply to any type of HO without interruption or with limited interruptions. For simplicity, the embodiments are described using DAPS HO, but that is merely one example of a HO type. Other HO types can include a HO without interruption time or an HO in which the UE maintains the connection with the source cell and target cell during HO.

FIG.7shows an embodiment of Dual Active Protocol Stack (DAPS) handover (HO). To reduce mobility interruption, a Dual Active Protocol Stack (DAPS) based handover procedure may be used. In the DAPS based handover procedure, the UE keeps simultaneous connection with the source cell and target cell until releasing the source cell after successful random access to the target cell.FIG.7illustrates in block 1, the source node configures the UE measurement procedures and the UE reports according to the measurement configuration. In block 2, the source node decides to handover the UE, based on MeasurementReport and RRM information. In block 3, the source node sends a Handover Request message to the target node, including the DAPS indicator to indicate that DAPS HO is requested. In block 4, admission control may be performed by the target node. In block 5, the target node decides to accept DAPS HO and sends the Handover Request Acknowledge to the source node, which includes a DAPS response indicator to indicate if a DAPS HO is accepted. In block 6, the source node triggers the Uu handover by sending an RRCReconfiguration message to the UE. For DRBs configured with DAPS, the source node may not stop transmitting downlink packets until it receives the Handover Success message from the target node in step 9a. In block 7a, the source node sends the Early Status Transfer message to the target node to convey the uplink/downlink PDCP SN status. Alternatively, in block 7, the source node sends the SN Status Transfer message to the target node to convey the uplink/downlink PDCP SN status. In block 8, the UE initiates random access to the target cell and completes the RRC handover procedure by sending a RRCReconfigurationComplete message to target node. In an example for DAPS HO, the UE may not detach from the source cell upon receiving the RRCReconfiguration message. The UE releases the source connection and configuration upon receiving an explicit release from the target node in step 9c. For DAPS HO the target node sends the Handover Success message to the source node in block 9a to inform that the UE has successfully accessed the target cell. In return, the source node sends the SN Status Transfer message for DRBs configured with DAPS in block 9b. In block 9c, the target node sends an RRCReconfiguration message to the UE, including a DAPS source release indication to explicitly the source connection and configuration. In block 10, there may be a path switch in response.

Coordination Configuration

FIG.3illustrated an example where the CU and DU are split (i.e. CU/DU split case) where the source or target CU/DU can decide/generate the DAPS related coordination configuration to be used by the source cell and the target cell during DAPS HO. As described below, the CU/DU coordination and/or interaction may be for a DAPS related coordination configuration

The DAPS related coordination configuration may include at least one of the following configurations:The DAPS related UL power coordination parameters/configurations;The DAPS related resource coordination parameters/configurations;The DAPS related capability indication, e.g. the index of FeatureSetUplinkPerCC and/or FeatureSetDownlinkPerCC selected by source cell.

There may be several alternative embodiments to generate the DAPS related coordination configuration and transfer it between the CU and the DU. Four example embodiments are described below. In a first alternative embodiment, the DU decides the DAPS related coordination configuration. In this embodiment, the CU sends a DAPS HO indication to the DU. This indication may also be referred to as an indicator and may be part of the handover. It may be referred to as a DAPS HO indication. The indication may indicate at least one of:A DAPS HO is to be prepared/configured/requested/initiated;A list of DRB information that a DAPS HO is to be prepared, configured, requested, and/or initiated for the concerned DRB;The type of DAPS HO is to be prepared, configured, requested, and/or initiated (e.g. inter-frequency DAPS HO, intra-frequency DAPS HO); orDAPS HO specific configuration (e.g. UL power coordination configuration, resource coordination configuration, DAPS related capability indication, etc.).

The DU may generate the DAPS related coordination configuration and send it to the CU (e.g. in response to reception of the DAPS HO indicator or the inter-frequency DAPS HO indicator from the CU).

In a second alternative embodiment, the CU may decide on the DAPS related coordination configuration. In this example, the CU generates the DAPS related coordination configuration and sends it to the DU.

In a third alternative embodiment, the DU generates the DAPS related coordination configuration (e.g. in response to reception of the DAPS HO indicator or the inter-frequency DAPS HO indicator from the CU) and sends it to the CU. If the CU wants to update or modify the configuration, the CU can generate and send the updated DAPS related coordination configuration to the DU.

In a fourth alternative embodiment, the CU generates DAPS related coordination configuration and sends it to the DU. If the DU wants to update/modify the configuration, the DU can generate and send the updated DAPS related coordination configuration to the CU.

The indication that is transferred from the CU to the DU can be configured several ways. In a first embodiment, the indication may be configured via the F1 interface. The indication (e.g. “DAPS HO Indicator” or “DAPS HO Type”) is configured as one information element in a F1-C message (e.g. UE CONTEXT MODIFICATION REQUEST message or UE CONTEXT SETUP REQUEST message).

In a second embodiment, the indication may be configured for an RRC message. In other words, the indication (e.g. “DAPS HO Indicator”, “DAPS HO Type”) is in a RRC message (e.g. CG-ConfigInfo, CG-Config or HandoverPreparationInformation message). The RRC message may be encapsulated as OCTET STRING/container in a F1-C message (e.g. UE CONTEXT MODIFICATION REQUEST message or UE CONTEXT SETUP REQUEST message).

The DAPS related coordination configuration transferred between the DU and the CU may be configured different ways. In a first embodiment, the DAPS related coordination configuration is included directly as information elements (e.g. “DAPS HO Power Coordination”, “DAPS HO Resource Coordination”) in a F1-C message (e.g. UE CONTEXT MODIFICATION REQUEST/RESPONSE message or UE CONTEXT SETUP REQUEST/RESPONSE message). The information elements may be included in the DU to CU RRC Information IE within a F1-C message. In a second embodiment, the DAPS related coordination configuration encapsulated as an OCTET

STRING/container (e.g. “powerCoordination”, “ConfigRestrictInfoDAPS”, “DAPS Resource Coordination Transfer Container”) may be included in a F1-C message (e.g. UE CONTEXT MODIFICATION REQUEST/RESPONSE message or UE CONTEXT SETUP REQUEST/RESPONSE message). The OCTET STRING/container may be included in the DU to CU RRC Information IE within a F1-C message.

The DAPS related coordination configuration described herein may include different parameters. Examples of the parameters include power coordination parameters and/or resource coordination parameters. Examples of each parameter are described below.

Power Coordination Parameter

The DAPS related uplink (UL) power coordination parameters/configurations may include different information. The power coordination may also be referred to as include at least one of the following items:The maximum total transmit power to be used by the UE in the source cell group during DAPS handover (e.g. DAPS Source Power, or p-DAPS-Source);The maximum total transmit power to be used by the UE in the target cell group during DAPS handover (e.g. DAPS Target Power, or p-DAPS-Target);The uplink power sharing mode that the UE uses in DAPS handover (e.g. Uplink Power Sharing DAPS Mode, or uplinkPowerSharingDAPS-Mode). The mode may be semi-static-mode1, semi-static-mode2, or dynamic; orCoordination assistance information, indicating whether the coordination of UL power between the source cell and the target cell is required or not
Resource Coordination Parameter

The HO indication may include a resource coordination parameter in addition to the power coordination parameter. In some embodiments, the parameters may be combined, or they may be separate parameters. DAPS related resource coordination parameters/configurations include at least one of:Source/target cell ID (e.g. CGI, PCI with carrier frequency);Uplink (UL) coordination information;Downlink (DL) coordination information;Coordination assistance information, indicating whether the coordination of resource utilization between the source cell and the target cell is required or not; orTime division multiplexing (TDM) pattern information, including UL/DL reference configuration indicating the time during which a UE configured with DAPS HO may be allowed to transmit (e.g. for single UL transmission).

The UL/DL coordination information may include a bitmap/bit string to indicate whether a specific frequency and time resource is intended to be used by the source/target cell. Then the target/source node assumes the resource which is not intended to be used by the source/target cell can be used for the target/source cell.FIG.8shows an embodiment of an uplink resource coordination string. This string may be one example of UL coordination information.

Each position in the bitmap may represent a Physical Resource Block (PRB) pair in a subframe. The value “0” may indicate “SpCell resource not intended to be used for transmission by the sending/target/source node”, while value “1” indicates “SpCell resource intended to be used for transmission by the sending/target/source node”. In other embodiments, the values may be switched. The bit string spans from the first PRB pair of the first represented subframe to the last PRB pair of the same subframe and then moves to the following PRBs in the following subframes in the same order. Each position may be applicable only in positions corresponding to UL subframes. The bit string may span across multiple contiguous subframes (e.g. maximum 40). The first position of the UL Coordination Information may correspond to the receiving node's subframe 0 in a receiving node's radio frame where System Frame Number (SFN)=0. The bit string may span across N subframes and with a length of N*M bits, where M is the PRB number in the single subframe. The UL Coordination Information may be continuously repeated. The same example can also be applied for DL resource coordination, where each position is applicable only in positions corresponding to DL subframes.

Referring back to the resource coordination parameter, one example was TDM pattern information. The TDM pattern information may include at least one of:Subframe assignment, indicating DL/UL subframe configuration (e.g. as shown in the following table); orHarq offset, indicating a HARQ subframe offset that is applied to the subframes designated as UL in the associated subframe assignment.

TABLE 1DL/UL subframe configurationUplink-Downlink-downlinkto-Uplinkconfig-Switch-pointSubframe numberurationperiodicity012345678905msDSUUUDSUUU15msDSUUDDSUUD25msDSUDDDSUDD310msDSUUUDDDDD410msDSUUDDDDDD510msDSUDDDDDDD65msDSUUUDSUUD

Examples for signaling structure on DAPS HO indication may include the following:

TABLE 2DAPS HO Indicator example.IE type andSemanticsAssignedIE/Group NamePresenceRangereferencedescriptionCriticalityCriticalityDAPS HOOENUMERATEDYESignoreIndicator(true, . . . )

TABLE 3DAPS HO Type example.IE type andSemanticsAssignedIE/Group NamePresenceRangereferencedescriptionCriticalityCriticalityDAPS HO TypeOENUMERATEDYESignore(intra-freq, inter-freq, . . . )

TABLE 4DAPS Request Information List example.IE type andIE/Group NamePresenceRangereferenceSemantics descriptionDAPS Request1 . . . <maxnoofDRBs>Information List>DRB IDMINTEGERIndicates that DAPS HO is(1 . . . 32, . . . )requested for the concernedDRB.

Examples for signaling structure for DAPS related UL power coordination parameters/configurations may include the examples shown in Tables 5-6.

TABLE 5First example for signaling structure for DAPS relatedUL power coordination parameters/configurations.IE/GroupIE type andAssignedNamePresenceRangereferenceSemantics descriptionCriticalityCriticalityDAPS SourceOINTEGERIdentical to the value of theYESignorePower(−30 . . . 33)p-DAPS-Source IE withinthe powerCoordination asdefined in TS 38.331.DAPS TargetOINTEGERIdentical to the value of theYESignorePower(−30 . . . 33)p-DAPS-Target IE withinthe powerCoordination asdefined in TS 38.331.Uplink PowerOENUMERATEDIdentical to the value of theYESignoreSharing DAPS{semi-static-uplinkPowerSharingDAPS-Modemode1, semi-Mode IE within thestatic-mode2,powerCoordination asdynamic}defined in TS 38.331.

TABLE 6Second example for signaling structure for DAPS relatedUL power coordination parameters/configurations.IE type andAssignedIE/Group NamePresenceRangereferenceSemantics descriptionCriticalityCriticalityPowerCoordinationOOCTETPowerCoordination, asYESignoreSTRINGdefined in TS 38.331.ConfigRestrictInfoDAPSOOCTETConfigRestrictInfoDAPS,YESignoreSTRINGas defined in TS 38.331.

In some embodiments, a HO preparation information message (e.g. HandoverPreparationInformation) may be transmitted. The following is example code for the message:

-- ASN1START-- TAG-HANDOVER-PREPARATION-INFORMATION-STARTHandoverPreparationInformation ::=SEQUENCE {criticalExtensionsCHOICE {c1CHOICE{handoverPreparationInformationHandoverPreparationInformation-IEs,spare3 NULL, spare2 NULL, spare1 NULL},criticalExtensionsFutureSEQUENCE { }}}HandoverPreparationInformation-IEs ::=SEQUENCE {*//skip unrelated part//*[[configRestrictInfoDAPS-r16ConfigRestrictInfoDAPS-r16OPTIONAL,sidelinkUEInformationNR-r16OCTET STRINGOPTIONAL,sidelinkUEInformationEUTRA-r16OCTET STRINGOPTIONAL,ueAssistanceInformationEUTRA-r16OCTET STRINGOPTIONAL,ueAssistanceInformationSCG-r16OCTET STRING (CONTAININGUEAssistanceInformation) OPTIONAL, -- Cond HO2needForGapsInfoNR-r16NeedForGapsInfoNR-r16OPTIONAL]],[[configRestrictInfoDAPS-v1640ConfigRestrictInfoDAPS-v1640OPTIONAL]],[[needForNCSG-InfoNR-r17NeedForNCSG-InfoNR-r17OPTIONAL,needForNCSG-InfoEUTRA-r17NeedForNCSG-InfoEUTRA-r17OPTIONAL,mbsInterestIndication-r17OCTET STRING (CONTAININGMBSInterestIndication-r17) OPTIONAL]]}ConfigRestrictInfoDAPS-r16 ::=SEQUENCE {powerCoordination-r16SEQUENCE {p-DAPS-Source-r16P-Max,p-DAPS-Target-r16P-Max,uplinkPowerSharingDAPS-Mode-r16ENUMERATED {semi-static-mode1,semi-static-mode2, dynamic }}OPTIONAL}ConfigRestrictInfoDAPS-v1640 ::= SEQUENCE {sourceFeatureSetPerDownlinkCC-r16FeatureSetDownlinkPerCC-Id,sourceFeatureSetPerUplinkCC-r16FeatureSetUplinkPerCC-Id}*//skip unrelated part//*-- TAG-HANDOVER-PREPARATION-INFORMATION-STOP-- ASN1STOP

The following tables illustrate example field descriptions:

TABLE 7Field descriptions for parameters for AS-Context.AS-Context field descriptionsconfigRestrictInfoDAPSIncludes fields for which source cell explicitly indicates the restrictionto be observed by target cell during DAPS handover.mbsInterestIndicationIncludes the information last reported by the UE in the NRMBSInterestIndication message, if any.needForGapsInfoNRIncludes measurement gap requirement information of the UE for NRtarget bands.selectedBandCombinationSNIndicates the band combination selected by SN in (NG)EN-DC, NE-DC,and NR-DC.sidelinkUEInformationEUTRAThis field includes SidelinkUEInformation IE as specified in TS36.331 [10].sidelinkUEInformationNRThis field includes SidelinkUEInformationNR IE.ueAssistanceInformationIncludes for each UE assistance feature the information last reported bythe UE, if any.ueAssistanceInformationSCGIncludes for each UE assistance feature associated with the SCG, theinformation last reported by the UE in the NR UEAssistanceInformationmessage for the SCG, if any.

TABLE 8Field descriptions for parameters for ConfigRestrictInfoDAPS.ConfigRestrictInfoDAPS field descriptionssource FeatureSetPerUplinkCC/sourceFeatureSetPerDownlinkCCIndicates an index referring to the position of theFeatureSetUplinkPerCC/FeatureSetDownlinkPerCC selected by source inthe featureSetsUplinkPerCC/featureSetsDownlinkPerCC.

Examples for signalling structure for DAPS related resource coordination parameters/configurations:

TABLE 9First example for signaling structure for DAPS related resource coordination parameters/configurations.IE Type andIE/Group NamePresenceRangeReferenceSemantics DescriptionSource Cell IDONR/E-UTRAThis IE indicates the SpCell.CGITarget Cell IDONR/E-UTRAThis IE indicates the SpCell.CGIUL CoordinationOBIT STRINGEach position in the bitmap represents a PRBInformation(6 . . . 4400, . . . )pair in a subframe; value “0” indicates “SpCellresource not intended to be used fortransmission by the sending node”, value “1”indicates “SpCell resource intended to be usedfor transmission by the sending node”. The bitstring spans from the first PRB pair of the firstrepresented subframe to the last PRB pair ofthe same subframe and then moves to thefollowing PRBs in the following subframes inthe same order. Each position is applicable onlyin positions corresponding to UL subframes orSL subframes for sidelink transmission.The bit string may span across multiplecontiguous subframes (maximum 40). The firstposition of the UL Coordination Informationcorresponds to the receiving node's subframe 0in a receiving node's radio frame where SFN = 0.The UL Coordination Information iscontinuously repeated.DL CoordinationOBIT STRINGEach position in the bitmap represents a PRBInformation(6 . . . 4400, . . . )pair in a subframe; value “0” indicates “SpCellresource not intended to be used fortransmission by the sending node”, value “1”indicates “SpCell resource intended to be usedfor transmission by the sending node”. The bitstring spans from the first PRB pair of the firstrepresented subframe to the last PRB pair ofthe same subframe and then moves to thefollowing PRBs in the following subframes inthe same order. Each position is applicable onlyin positions corresponding to DL subframes.The bit string may span across multiplecontiguous subframes (maximum 40). The firstposition of the DL Coordination Informationcorresponds to the receiving node's subframe 0in a receiving node's radio frame where SFN = 0.The DL Coordination Information iscontinuously repeated.CoordinationOENUMERATEDAssistance(CoordinationInformationNotRequired, . . . )

TABLE 10Second example for signaling structure for DAPS relatedresource coordination parameters/configurations.IE type andAssignedIE/Group NamePresenceRangereferenceSemantics descriptionCriticalityCriticalityResourceOOCTETIncludes the DAPSYESignoreCoordinationSTRINGResource CoordinationTransferInformation IE.Container(Note: The DAPSResource CoordinationInformation IEincludes IEs similar tooption 1, which may bedefined in otherinterfaces, e.g.XnAP/X2AP.)

For inter-CU mobility, there may be several embodiments to generate/transfer the DAPS related coordination configuration between the source CU/node and the target CU/node. Example embodiments for the generation/transfer include:Option 1: The source CU/node transfers the generated DAPS related coordination configuration to the target CU/node via a Xn/X2 message, e.g. Handover Request message.Option 1a: If the target CU/node wants to update/modify the DAPS related coordination configuration, the target CU/node sends the updated DAPS related coordination configuration to the source CU/node via a Xn/X2 message, e.g. Handover Request Acknowledge message.Option 2: The target CU/node transfers the generated DAPS related coordination configuration to the source CU/node via a Xn/X2 message, e.g. Handover Request Acknowledge message.Option 2a: If the source CU/node wants to update/modify the DAPS related coordination configuration, the source CU/node sends the updated DAPS related coordination configuration to the target CU/node via a Xn/X2 message.

The DAPS related coordination configuration can be transferred by one of the following options:Option 1: Include the configuration as information elements in a Xn/X2 message, e.g. Handover Request message or Handover Request Acknowledge message.Option 2: Include the configuration in a RRC message, e.g. HandoverPreparationInformation message. The RRC message is encapsulated as OCTET STRING/container in a Xn/X2 message, e.g. Handover Request message.
DAPS HO Status

The CU/DU coordination/interaction may rely on a DAPS HO status. The DAPS HO status may be used to inform the DU when to start/complete DAPS HO, e.g. for resource scheduling, disabling/enabling some features that cannot be coexisted with DAPS HO, etc. This may be on DAPS HO initiation. The CU sends a DAPS HO indication to the DU, to indicate that DAPS HO is to be prepared, configured, requested, or initiated. The indication for the DAPS HO initiation may indicate at least one of:A DAPS HO is to be prepared/configured/requested/initiated;A list of DRB information that a DAPS HO is to be prepared, configured, requested, or initiated for the concerned DRB;The type of DAPS HO is to be prepared, configured, requested, or initiated (e.g. inter-frequency DAPS HO, intra-frequency DAPS HO).DAPS HO specific configuration (e.g. UL power coordination configuration, resource coordination configuration, or DAPS related capability indication).

In response to reception of DAPS HO indication, the DU may perform at least one of:Consider the DAPS HO is to be prepared/configured/requested/initiated.Use the received/generated DAPS related coordination parameters/configurations for the purpose of power and/or resource coordination between the source cell and target cell in DAPS HO.Disable/disallow the feature/operation that can not be co-existed with DAPS HO (e.g. multi-TRP). For example, the DU can disable SDM based Single-DCI based multi-TRP via Enhanced TCI States Activation/Deactivation for UE-specific PDSCH MAC CE.

For the DAPS HO response to reception of a DAPS HO indication from the CU, the DU may accept/reject the DAPS request or partial DAPS request (e.g. accept DAPS request on some DRBs within the DRB list for DAPS request, and reject DAPS request on other DRBs within the DRB list for DAPS request). The DU sends a DAPS HO response indication to the CU. The DAPS HO response indication may include at least one of:An indication to indicate that DAPS HO is accepted/rejected; orA list of DRB information to indicate whether a DAPS HO is accepted/rejected for the concerned DRB.

For inter-CU mobility, in response to reception of a DAPS HO response indication from the target CU, the source CU may send a DAPS HO response indication to the source DU. If the DAPS HO response indication indicates that the DAPS HO is rejected, the source DU may discard/release the previously generated/received DAPS related coordination configuration.FIG.9-12illustrate example communications that include the DAPS HO initiation and DAPS HO response described above.

The UE successfully transfers/switches to a target node, e.g. successful completion random access procedure to the target cell. The CU sends an indication (e.g. DAPS HO Completion Indication, Source Cell Release Indication, or set the value of DAPS HO Indication to “completion/release/stop”) to the DU indicating that a DAPS HO is to be completed or the source cell is to be released (e.g. when the CU decides to release the source cell or when generating/sending a RRC reconfiguration message including daps-SourceRelease IE). In some embodiments, it may be when the CU successfully releases the source cell (e.g. after sending a RRC reconfiguration message including daps-SourceRelease IE to the UE). In response to reception of the indication for DAPS HO completion/source cell release, the DU may perform at least one of:Consider the DAPS HO is to be completed or the source cell is to be released.Stop using the received/generated DAPS related coordination parameters/configurations for the purpose of power and/or resource coordination between the source cell and target cell in DAPS HO. The DU may replace the old configuration with new received/generated configuration.Enable/allow the feature/operation that cannot be co-existed with DAPS HO (e.g. multi-TRP). For example, the DU can enable SDM based Single-DCI based multi-TRP via Enhanced TCI States Activation/Deactivation for UE-specific PDSCH MAC CE.

The DAPS HO related indication transferred between the CU and the DU can be configured by one of the following options:Option 1: Include an indication (e.g. “DAPS HO Indicator”) as one information element in a F1-C message (e.g. UE CONTEXT MODIFICATION REQUEST/RESPONSE UE message or CONTEXT SETUP REQUEST/RESPONSE message).Option 2: Include an indication (e.g. “DAPS HO Indicator”) in an RRC message (e.g. CG-ConfigInfo, or CG-Config or HandoverPreparationInformation message). The RRC message is encapsulated as OCTET STRING in a F1-C message (e.g. UE CONTEXT MODIFICATION REQUEST message or UE CONTEXT SETUP REQUEST message).

The following are example signaling structures for a DAPS HO related indication:

TABLE 11First example for signaling structure for DAPS HO related indication.IE/GroupIE type andSemanticsAssignedNamePresenceRangereferencedescriptionCriticalityCriticalityDAPS HOOENUMERATEDYESignoreStatus/(true/initiation/Indicatorrequest, accept/reject, release/stop/completion, . . . )

TABLE 12Second example for signaling structure for DAPS HO related indication.IE/GroupIE type andSemanticsNamePresenceRangereferencedescriptionDAPS1 . . . <maxnoofDRBs>ResponseInformationList>DRB IDMINTEGER(1 . . . 32, . . . )>DAPSMENUMERATEDIndicates whetherResponse(DAPS HOthe DAPSIndicatoraccepted,_DAPSHandover has beenHO notaccepted.accepted, . . . )

TABLE 13Third example for signaling structure for DAPS HO related indication.IE/GroupIE type andSemanticsAssignedNamePresenceRangereferencedescriptionCriticalityCriticalityDAPS HOOENUMERATEDYESignoreCompletion/Source(true, . . . )Cell ReleaseIndicator

The DAPS HO description above includes an indication or indicator that is transmitted. That indication may include parameters such as power coordination and/or resource coordination to improve performance during the handover. The description above applies to the following communication examples described with respect toFIGS.9-12.

FIG.9shows one embodiment of Distributed Unit (DU) and Centralized Unit (CU) communications for handover (HO). The CU and DU are discussed above with respect toFIG.3and are example basestations.FIG.9illustrates communications between the user equipment (UE), a source DU, a target DU, and a CU. The example shown inFIG.11is similar toFIG.9except there is a source CU and a target CU.

FIG.9illustrates that downlink (DL) user data is from the CU to the source DU or the UE, while uplink (UL) user data is from the UE to the source DU or the CU. In block902, a measurement report (MeasurementReport) message is sent form the UE to the source DU. In block904, the source DU sends an UL RRC MESSAGE TRANSFER message to the CU to convey the received measurement report message.

In block906, the CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU to query the latest configuration. The message may include a DAPS HO indication to the source DU to indicate that a DAPS HO is to be prepared, configured, initiated or requested. The DAPS HO indication may be the HO indication/indicator described above. The indication may include a list of DRB information that a DAPS HO is to be prepared, configured, initiated, or requested for the concerned DRB, or which type of DAPS HO is to be prepared, configured, initiated, or requested (e.g. inter-frequency DAPS HO, intra-frequency DAPS HO), and/or DAPS HO specific configuration.

In block908, the source DU responds with a UE CONTEXT MODIFICATION RESPONSE message that includes full configuration information. If a DAPS HO indication or a inter-frequency DAPS HO indication is received, the source DU may generate and include DAPS related coordination configuration (e.g. UL power coordination parameters or configurations and/or resource coordination parameters or configurations) into the message. The DU uses the generated coordination configuration for power and/or resource coordination during DAPS HO. If a DAPS HO indication is received, the source DU may disable multi-TRP operation during DAPS HO (e.g. disable SDM based Single-DCI based multi-TRP via Enhanced TCI States Activation/Deactivation for UE-specific PDSCH MAC CE).

In block910, the CU sends a UE CONTEXT SETUP REQUEST message to the target DU to create a UE context and setup one or more data bearers. The UE CONTEXT SETUP REQUEST message may include a HandoverPreparationInformation message. The UE CONTEXT SETUP REQUEST message or HandoverPreparationInformation message may include the DAPS related coordination configuration. The coordination configuration may also be referred to as the HO related configuration. The UE CONTEXT SETUP REQUEST message may include a DAPS HO indication to the target DU to indicate that a DAPS HO is to be prepared, configured, initiated, or requested. It may also include a list of DRB information that a DAPS HO is to be prepared, configured, initiated, or requested for the concerned DRB, and/or which type of DAPS HO is to be prepared, configured, initiated, or requested (e.g. inter-frequency DAPS HO, intra-frequency DAPS HO), and/or a DAPS HO specific configuration.

In block912, the target DU responds to the CU with a UE CONTEXT SETUP RESPONSE message. If a DAPS HO indication is received, the target DU may disable multi-TRP operation during DAPS HO (e.g. disable SDM based Single-DCI based multi-TRP via Enhanced TCI States Activation/Deactivation for UE-specific PDSCH MAC CE). If the DAPS related coordination configuration is received, the target DU uses the received coordination configuration for the purpose of either power or resource coordination during DAPS HO.

In block914, the CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU, which includes a generated RRCReconfiguration message and indicates to stop the data transmission for the UE. The RRCReconfiguration message may include the DAPS related coordination configuration for the UE. The source DU also sends a Downlink Data Delivery Status frame to inform the CU about the unsuccessfully transmitted downlink data to the UE. For the DAPS handover, the UE CONTEXT MODIFICATION REQUEST message in block914may indicate to stop the data transmission only for the DRB(s) not subject to DAPS handover or may not indicate to stop the data transmission at all. Instead, the DL RRC Message Transfer procedure may be used to carry the handover command to the UE. The UE CONTEXT MODIFICATION REQUEST message that indicates to stop the data transmission for the UE is sent to the source DU once the CU knows that the UE has successfully accessed the target DU, for which the source DU sends a DDDS frame about the unsuccessfully transmitted downlink data to the CU.

In block916, the source DU forwards the received RRCReconfiguration message to the UE. In block918, the source DU responds to the CU with the UE CONTEXT MODIFICATION RESPONSE message. There may be an optional downlink data delivery status sent from the source DU to the CU. In block920, a Random Access procedure is performed at the target DU. The target DU sends a Downlink Data Delivery Status frame to inform the CU. Downlink packets (e.g. PDCP PDUs) not successfully transmitted in the source DU, are sent from the CU to the target DU. In some embodiments, it is up to CU implementation whether to start sending DL User Data to DU before or after reception of the Downlink Data Delivery Status. In block922, the UE responds to the target DU with an RRCReconfigurationComplete message. In block924, the target DU sends an UL RRC MESSAGE TRANSFER message to the CU to convey the received RRCReconfigurationComplete message. Downlink packets are sent to the UE and/or uplink packets are sent from the UE, which are forwarded to the CU through the target DU.

In block926, the target CU decides to release the source cell connection. The target CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU, which includes a generated RRCReconfiguration message including a DAPS-SourceRelease information element (IE) to indicate the release of source cell connection. The UE CONTEXT MODIFICATION REQUEST message may include an indication to indicate the source DU that a DAPS HO is to be completed or source cell is to be released (e.g. set the value of DAPS HO indication to “completion/release/stop”). If the indication is received, the target DU may stop using the DAPS related coordination configuration for the purpose of power and/or resource coordination during DAPS HO, and/or allow multi-TRP operation during DAPS HO (e.g. enable SDM based Single-DCI based multi-TRP via Enhanced TCI States Activation/Deactivation for UE-specific PDSCH MAC CE).

In block928, the target DU forwards the received RRCReconfiguration message to the UE. In block930, the source DU responds to the CU with the UE CONTEXT MODIFICATION RESPONSE message. In block932, the UE responds to the target DU with an RRCReconfigurationComplete message. In block934, the target DU sends an UL RRC MESSAGE TRANSFER message to the CU to convey the received RRCReconfigurationComplete message. In block936, the CU sends a UE CONTEXT RELEASE COMMAND message to the source DU. In block938, the source DU releases the UE context and responds the CU with a UE CONTEXT RELEASE COMPLETE message. In alternative embodiments, the order of blocks924-938may vary.

In some embodiments, the CU may update and/or modify the DAPS related coordination configuration and send the requested/updated/new DAPS related coordination configuration (e.g. requested/new values for the DAPS related coordination parameters) to the source DU (e.g. via the UE CONTEXT MODIFICATION REQUEST message) in block914. If the requested/new/updated configuration is received, the source DU uses the received configuration for the purpose of either power coordination or resource coordination during DAPS HO.

FIG.10shows another embodiment of Distributed Unit (DU) and Centralized Unit (CU) communications for handover (HO). The CU and DU are discussed above with respect toFIG.3and are example basestations.FIG.10illustrates communications between the user equipment (UE), a source DU, a target DU, and a CU. In block1002, a measurement report (MeasurementReport) message is sent form the UE to the source DU. In block1004, the source DU sends an UL RRC MESSAGE TRANSFER message to the CU to convey the received measurement report message. In block1006, the CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU to query the latest configuration. In block1008, the source DU responds with a UE CONTEXT MODIFICATION RESPONSE message that includes full configuration information.

In block1010, the CU sends a UE CONTEXT SETUP REQUEST message to the target DU to create a UE context and setup one or more data bearers. The message may include a DAPS HO indication to the source DU to indicate that a DAPS HO is to be prepared, configured, initiated, or requested. The DAPS HO indication may be the HO indication/indicator described above. The indication may include a list of DRB information that a DAPS HO is to be prepared, configured, initiated, or requested for the concerned DRB, or which type of DAPS HO is to be prepared, configured, initiated, or requested (e.g. inter-frequency DAPS HO, intra-frequency DAPS HO), and/or DAPS HO specific configuration.

The UE CONTEXT SETUP REQUEST message may include a HandoverPreparationInformation message. The UE CONTEXT SETUP REQUEST message or HandoverPreparationInformation message may include the DAPS related coordination configuration. The coordination configuration may also be referred to as the HO related configuration.

In block1012, the target DU responds to the CU with a UE CONTEXT SETUP RESPONSE message. If a DAPS HO indication is received, the target DU may disable multi-TRP operation during DAPS HO (e.g. disable SDM based Single-DCI based multi-TRP via Enhanced TCI States Activation/Deactivation for UE-specific PDSCH MAC CE). If the DAPS related coordination configuration is received, the target DU uses the received coordination configuration for the purpose of power and/or resource coordination during DAPS HO.

In block1014, the CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU, which includes a generated RRCReconfiguration message and indicates to stop the data transmission for the UE. The RRCReconfiguration message may include the DAPS related coordination configuration to the UE. The CU may include a DAPS HO indication and/or DAPS related coordination configuration into the message. If the coordination configuration is received, the source DU uses the received configuration for power coordination and/or resource coordination during DAPS HO. The source DU may send a Downlink Data Delivery Status frame to inform the CU about the unsuccessfully transmitted downlink data to the UE. If a DAPS related information (e.g. DAPS HO indication, DAPS related resource/power coordination configuration, transmission stop indicator) is received, the source DU may disable multi-TRP operation during DAPS HO (e.g. disable SDM based Single-DCI based multi-TRP via Enhanced TCI States Activation/Deactivation for UE-specific PDSCH MAC CE). The UE CONTEXT MODIFICATION REQUEST message may indicate to stop the data transmission for the UE is sent to the source DU once the CU knows that the UE has successfully accessed the target DU, for which the source DU sends a DDDS frame about the unsuccessfully transmitted downlink data to the CU.

In some embodiments, the CU may send the generated DAPS related coordination configuration to the source DU (e.g. via the UE CONTEXT MODIFICATION REQUEST message in block1006). In some embodiments, the source DU may update/modify the DAPS related coordination configuration and send the requested/updated/new coordination configuration to the CU (e.g. via the UE CONTEXT MODIFICATION RESPONSE message in block1008).

In block1016, the source DU forwards the received RRCReconfiguration message to the UE. In block1018, the source DU responds to the CU with the UE CONTEXT MODIFICATION RESPONSE message. There may be an optional downlink data delivery status sent from the source DU to the CU. In block1020, a Random Access procedure is performed at the target DU. The target DU sends a Downlink Data Delivery Status frame to inform the CU. Downlink packets (e.g. PDCP PDUs) not successfully transmitted in the source DU, are sent from the CU to the target DU. In some embodiments, it is up to CU implementation whether to start sending DL User Data to DU before or after reception of the Downlink Data Delivery Status. In block1022, the UE responds to the target DU with an RRCReconfigurationComplete message. In block1024, the target DU sends an UL RRC MESSAGE TRANSFER message to the CU to convey the received RRCReconfigurationComplete message. Downlink packets are sent to the UE and/or uplink packets are sent from the UE, which are forwarded to the CU through the target DU.

In block1026, the target CU decides to release the source cell connection. The target CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU, which includes a generated RRCReconfiguration message including a DAPS-SourceRelease information element (IE) to indicate the release of source cell connection. The UE CONTEXT MODIFICATION REQUEST message may include an indication to indicate the source DU that a DAPS HO is to be completed or source cell is to be released (e.g. set the value of DAPS HO indication to “completion/release/stop”). If the indication is received, the target DU may stop using the configuration for the purpose of power and/or resource coordination during DAPS HO, and/or allow multi-TRP operation during DAPS HO (e.g. enable SDM based Single-DCI based multi-TRP via Enhanced TCI States Activation/Deactivation for UE-specific PDSCH MAC CE).

In block1028, the target DU forwards the received RRCReconfiguration message to the UE. In block1030, the source DU responds to the CU with the UE CONTEXT MODIFICATION RESPONSE message. In block1032, the UE responds to the target DU with an RRCReconfigurationComplete message. In block1034, the target DU sends an UL RRC MESSAGE TRANSFER message to the CU to convey the received RRCReconfigurationComplete message. In block1036, the CU sends a UE CONTEXT RELEASE COMMAND message to the source DU. In block1038, the source DU releases the UE context and responds the CU with a UE CONTEXT RELEASE COMPLETE message. In alternative embodiments, the order of blocks1024-1038may vary.

In some embodiments, the CU may send the generated DAPS related coordination configuration to the source DU, e.g. via the UE CONTEXT MODIFICATION REQUEST message in1006. In some embodiments, the source DU may update/modify the DAPS related coordination configuration and send the requested/updated/new coordination configuration to the CU, e.g. via the UE CONTEXT MODIFICATION RESPONSE message in1008.

In some embodiments, the target DU may accept or reject partial DAPS request (e.g. accept DAPS request on some DRBs within the DRB list for DAPS request, and reject DAPS request on other DRBs within the DRB list for DAPS request). In alternative embodiments, it may update/modify the DAPS related coordination configuration received from the CU. The target DU may send the DAPS HO response indication (e.g. accepted/rejected DAPS request DRB information list) to the CU (e.g. via the UE CONTEXT SETUP RESPONSE message in block912or1012). The target DU may generate the requested/updated/new DAPS related coordination configuration (e.g. based on the accepted/rejected DAPS request DRB information), and send the configuration to the CU (e.g. via the UE CONTEXT SETUP RESPONSE message in block912or1012). The CU sends the requested/updated/new DAPS related coordination configuration to the source DU (e.g. via UE CONTEXT MODIFICATION REQUEST message in block914or1014). The source DU may apply the requested/updated/new DAPS related coordination configuration and use the configuration for the purpose of either power and/or resource coordination during DAPS HO.

In some embodiments, the target DU may reject DAPS request (e.g. reject DAPS request on all DRBs within the DRB list for DAPS request) and send the DAPS HO reject/response information to the CU (e.g. via the UE CONTEXT SETUP RESPONSE message in block912or1012). The CU sends the DAPS reject/response information to the source DU (e.g. via UE CONTEXT MODIFICATION REQUEST message in block914or1014). If the DAPS reject information is received, the source DU may discard/release the previously generated DAPS related coordination configuration.

FIG.11shows one embodiment of Distributed Unit (DU) and target Centralized Unit (CU) communications for inter-CU handover (HO). The CU and DU are discussed above with respect toFIG.3and are example basestations.FIG.11illustrates communications between the user equipment (UE), a source DU, a target DU, a source CU, and a target CU.

FIG.11illustrates that downlink (DL) user data is from the source CU to the source DU or the UE, while uplink (UL) user data is from the UE to the source DU or the source CU. In block1102, a measurement report (MeasurementReport) message is sent form the UE to the source DU. In block1104, the source DU sends an UL RRC MESSAGE TRANSFER message to the source CU to convey the received measurement report message.

In block1106, the source CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU to query the latest configuration. The message may include a DAPS HO indication to the source DU to indicate that a DAPS HO is to be prepared, configured, initiated or requested. The DAPS HO indication may be the HO indication/indicator described above. The indication may include a list of DRB information that a DAPS HO is to be prepared, configured, initiated, or requested for the concerned DRB, or which type of DAPS HO is to be prepared, configured, initiated, or requested (e.g. inter-frequency DAPS HO, intra-frequency DAPS HO), and/or DAPS HO specific configuration.

In block1108, the source DU responds with a UE CONTEXT MODIFICATION RESPONSE message that includes full configuration information. If a DAPS HO indication or a inter-frequency DAPS HO indication is received, the source DU may generate and include DAPS HO related coordination configuration (e.g. UL power coordination parameters or configurations and/or resource coordination parameters or configurations) into the message. The DU uses the generated coordination configuration for power and/or resource coordination during DAPS HO. If a DAPS HO indication is received, the source DU may disable multi-TRP operation during DAPS HO (e.g. disable SDM based Single-DCI based multi-TRP via Enhanced TCI States Activation/Deactivation for UE-specific PDSCH MAC CE).

In block1110, the source CU sends a Handover Request message to the target CU. The message may include a HandoverPreparationInformation message. The message may include a DAPS HO indication to indicate that a DAPS HO is to be prepared, configured, initiated or requested, a list of DRB information that a DAPS HO is to be prepared, configured, initiated or requested for the concerned DRB, which type of DAPS HO is to be prepared, configured, initiated or requested (e.g. inter-frequency DAPS HO, intra-frequency DAPS HO), and/or DAPS specific configuration. The message may also include the DAPS HO related coordination configuration (e.g. UL power coordination parameters/configurations and/or resource coordination parameters/configurations).

In block1112, the target DU sends a UE CONTEXT SETUP REQUEST message to the target CU to create a UE context and setup one or more data bearers. The UE CONTEXT SETUP REQUEST message may include a HandoverPreparationInformation message. The UE CONTEXT SETUP REQUEST message or HandoverPreparationInformation message may include the DAPS related coordination configuration. The coordination configuration may also be referred to as the HO related configuration. The UE CONTEXT SETUP REQUEST message may include a DAPS HO indication to the target CU to indicate that a DAPS HO is to be prepared, configured, initiated, or requested. It may also include a list of DRB information that a DAPS HO is to be prepared, configured, initiated, or requested for the concerned DRB, and/or which type of DAPS HO is to be prepared, configured, initiated, or requested (e.g. inter-frequency DAPS HO, intra-frequency DAPS HO), and/or a DAPS HO specific configuration.

In block1114, the target CU responds to the target DU with a UE CONTEXT SETUP RESPONSE message. If a DAPS HO indication is received, the target CU may disable multi-TRP operation during DAPS HO (e.g. disable SDM based Single-DCI based multi-TRP via Enhanced TCI States Activation/Deactivation for UE-specific PDSCH MAC CE). If the DAPS related coordination configuration is received, the target CU uses the received coordination configuration for the purpose of either power or resource coordination during DAPS HO.

In block1116, the target CU decides whether to accept DAPS HO and sends the Handover Request Acknowledge message to the source CU. The message may include a handover command (i.e. RRCreconfiguration message). The message may include a DAPS response information to indicate if a DAPS HO is accepted/rejected or if a DAPS HO is accepted/rejected for the concerned DRB (e.g. a list of DRB information to indicate whether a DAPS HO is accepted/rejected for the concerned DRB). The message may also include the requested/updated/new DAPS related coordination configuration, which is generated/requested by the target CU or/and the target DU.

In block1118, the source CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU, which includes a generated RRCReconfiguration message and indicates to stop the data transmission for the UE. The RRCReconfiguration message may include the DAPS related coordination configuration for the UE. The source DU also sends a Downlink Data Delivery Status frame to inform the CU about the unsuccessfully transmitted downlink data to the UE. For the DAPS handover, the UE CONTEXT MODIFICATION REQUEST message in block1118may indicate to stop the data transmission only for the DRB(s) not subject to DAPS handover or may not indicate to stop the data transmission at all. Instead, the DL RRC Message Transfer procedure may be used to carry the handover command to the UE. The UE CONTEXT MODIFICATION REQUEST message that indicates to stop the data transmission for the UE is sent to the source DU once the source CU knows that the UE has successfully accessed the target DU, for which the source DU sends a DDDS frame about the unsuccessfully transmitted downlink data to the source CU.

In block1120, the source DU forwards the received RRCReconfiguration message to the UE. In block1122, the source DU responds to the source CU with the UE CONTEXT MODIFICATION RESPONSE message. There may be an optional downlink data delivery status sent from the source DU to the source CU. In block1124, a Random Access procedure is performed at the target DU. The target DU sends a Downlink Data Delivery Status frame to inform the source CU. Downlink packets (e.g. PDCP PDUs) not successfully transmitted in the source DU, are sent from the source CU to the target DU. In some embodiments, it is up to source CU implementation whether to start sending DL User Data to DU before or after reception of the Downlink Data Delivery Status. In block1126, the UE responds to the target DU with an RRCReconfigurationComplete message. In block1128, the target DU sends an UL RRC MESSAGE TRANSFER message to the source CU to convey the received RRCReconfigurationComplete message. Downlink packets are sent to the UE and/or uplink packets are sent from the UE, which are forwarded to the source CU through the target DU.

In block1130, for a DAPS handover, the target CU sends the Handover Success message to the source CU to inform that the UE has successfully accessed the target cell. In return, the source CU sends the SN Status Transfer message in block1132for DRBs configured with DAPS for data forwarding to the target CU.

In block1134, the target CU decides to release the source cell connection. The target CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU, which includes a generated RRCReconfiguration message including a DAPS-SourceRelease information element (IE) to indicate the release of source cell connection. The UE CONTEXT MODIFICATION REQUEST message may include an indication to indicate the source DU that a DAPS HO is to be completed or source cell is to be released (e.g. set the value of DAPS HO indication to “completion/release/stop”). If the indication is received, the target DU may stop using the DAPS related coordination configuration for the purpose of power and/or resource coordination during DAPS HO, and/or allow multi-TRP operation during DAPS HO (e.g. enable SDM based Single-DCI based multi-TRP via Enhanced TCI States Activation/Deactivation for UE-specific PDSCH MAC CE).

In block1136, the target DU forwards the received RRCReconfiguration message to the UE. In block1138, the source DU responds to the target CU with the UE CONTEXT MODIFICATION RESPONSE message. In block1140, the UE responds to the target DU with an RRCReconfigurationComplete message. In block1142, the target DU sends an UL RRC MESSAGE TRANSFER message to the target CU to convey the received RRCReconfigurationComplete message. In block1144, the target CU sends a UE CONTEXT RELEASE COMMAND message to the source CU. In block1146, the source CU releases the UE context and in block1148receives a response from the source DU including a UE CONTEXT RELEASE COMPLETE message. In alternative embodiments, the order of blocks1132-1148may vary.

In some embodiments, the source CU may update and/or modify the DAPS related coordination configuration and send the requested/updated/new DAPS related coordination configuration (e.g. requested/new values for the DAPS related coordination parameters from the target CU) and send the requested/updated/new coordination configuration to the source DU (e.g. via the UE CONTEXT MODIFICATION REQUEST message in block1118or1218). If the requested/new/updated coordination configuration is received, the source DU uses the received configuration for the purpose of power coordination and/or resource coordination during DAPS HO.

In some embodiments, the source CU may send the DAPS HO response information and/or the requested/updated/new coordination configuration to the source DU, which is received from the target CU. It may be sent via the UE CONTEXT MODIFICATION REQUEST message in block1118or1218. If the requested/new/updated coordination configuration is received, the source DU uses the received configuration for power coordination and/or resource coordination during DAPS HO. If the DAPS HO response information indicates that the DAPS HO is rejected, the source DU may discard/release the previously generated/received DAPS related coordination configuration.

FIG.12shows another embodiment of Distributed Unit (DU) and target Centralized Unit (CU) communications for inter-CU handover (HO). The CU and DU are discussed above with respect toFIG.3and are example basestations.FIG.12illustrates communications between the user equipment (UE), a source DU, a target DU, a source CU, and a target CU.

FIG.12illustrates that downlink (DL) user data is from the source CU to the source DU or the UE, while uplink (UL) user data is from the UE to the source DU or the source CU. In block1202, a measurement report (MeasurementReport) message is sent form the UE to the source DU. In block1204, the source DU sends an UL RRC MESSAGE TRANSFER message to the source CU to convey the received measurement report message.

In block1206, the source CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU to query the latest configuration. The message may include a DAPS HO indication to the source DU to indicate that a DAPS HO is to be prepared, configured, initiated or requested. The DAPS HO indication may be the HO indication/indicator described above. The indication may include a list of DRB information that a DAPS HO is to be prepared, configured, initiated, or requested for the concerned DRB, or which type of DAPS HO is to be prepared, configured, initiated, or requested (e.g. inter-frequency DAPS HO, intra-frequency DAPS HO), and/or DAPS HO specific configuration.

In block1208, the source DU responds with a UE CONTEXT MODIFICATION RESPONSE message that includes full configuration information. If a DAPS HO indication or a inter-frequency DAPS HO indication is received, the source DU may generate and include DAPS related coordination configuration (e.g. UL power coordination parameters or configurations and/or resource coordination parameters or configurations) into the message. The DU uses the generated coordination configuration for power and/or resource coordination during DAPS HO. If a DAPS HO indication is received, the source DU may disable multi-TRP operation during DAPS HO (e.g. disable SDM based Single-DCI based multi-TRP via Enhanced TCI States Activation/Deactivation for UE-specific PDSCH MAC CE).

In block1210, the source CU sends a Handover Request message to the target CU. The message may include a HandoverPreparationInformation message. The message may include a DAPS HO indication to indicate that a DAPS HO is to be prepared, configured, initiated or requested, a list of DRB information that a DAPS HO is to be prepared, configured, initiated or requested for the concerned DRB, which type of DAPS HO is to be prepared, configured, initiated or requested (e.g. inter-frequency DAPS HO, intra-frequency DAPS HO), and/or DAPS specific configuration. The message may also include the DAPS related coordination configuration (e.g. UL power coordination parameters/configurations and/or resource coordination parameters/configurations).

In block1212, the target DU sends a UE CONTEXT SETUP REQUEST message to the target CU to create a UE context and setup one or more data bearers. The UE CONTEXT SETUP REQUEST message may include a HandoverPreparationInformation message. The UE CONTEXT SETUP REQUEST message or HandoverPreparationInformation message may include the DAPS related coordination configuration. The coordination configuration may also be referred to as the HO related configuration. The UE CONTEXT SETUP REQUEST message may include a DAPS HO indication to the target CU to indicate that a DAPS HO is to be prepared, configured, initiated, or requested. It may also include a list of DRB information that a DAPS HO is to be prepared, configured, initiated, or requested for the concerned DRB, and/or which type of DAPS HO is to be prepared, configured, initiated, or requested (e.g. inter-frequency DAPS HO, intra-frequency DAPS HO), and/or a DAPS HO specific configuration.

In block1214, the target CU responds to the target DU with a UE CONTEXT SETUP RESPONSE message. If a DAPS HO indication is received, the target CU may disable multi-TRP operation during DAPS HO (e.g. disable SDM based Single-DCI based multi-TRP via Enhanced TCI States Activation/Deactivation for UE-specific PDSCH MAC CE). If the DAPS related coordination configuration is received, the target CU uses the received coordination configuration for the purpose of either power or resource coordination during DAPS HO.

In block1216, the target CU decides whether to accept DAPS HO and sends the Handover Request Acknowledge message to the source CU. The message may include a handover command (i.e. RRCreconfiguration message). The message may include a DAPS response information to indicate if a DAPS HO is accepted/rejected or if a DAPS HO is accepted/rejected for the concerned DRB (e.g. a list of DRB information to indicate whether a DAPS HO is accepted/rejected for the concerned DRB). The message may also include the requested/updated/new DAPS related coordination configuration, which is generated/requested by the target CU or/and the target DU.

In block1218, the source CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU, which includes a generated RRCReconfiguration message and indicates to stop the data transmission for the UE. The RRCReconfiguration message may include the DAPS related coordination configuration to the UE. The source CU may include a DAPS HO indication and/or DAPS related coordination configuration into the message. If the coordination configuration is received, the source DU uses the received configuration for power coordination and/or resource coordination during DAPS HO. The source DU may send a Downlink Data Delivery Status frame to inform the CU about the unsuccessfully transmitted downlink data to the UE. If a DAPS related information (e.g. DAPS HO indication, DAPS related resource/power coordination configuration, transmission stop indicator) is received, the source DU may disable multi-TRP operation during DAPS HO (e.g. disable SDM based Single-DCI based multi-TRP via Enhanced TCI States Activation/Deactivation for UE-specific PDSCH MAC CE). The UE CONTEXT MODIFICATION REQUEST message may indicate to stop the data transmission for the UE is sent to the source DU once the source CU knows that the UE has successfully accessed the target DU, for which the source DU sends a DDDS frame about the unsuccessfully transmitted downlink data to the source CU.

In block1220, the source DU forwards the received RRCReconfiguration message to the UE. In block1222, the source DU responds to the source CU with the UE CONTEXT MODIFICATION RESPONSE message. There may be an optional downlink data delivery status sent from the source DU to the source CU. In block1224, a Random Access procedure is performed at the target DU. The target DU sends a Downlink Data Delivery Status frame to inform the source CU. Downlink packets (e.g. PDCP PDUs) not successfully transmitted in the source DU, are sent from the source CU to the target DU. In some embodiments, it is up to source CU implementation whether to start sending DL User Data to DU before or after reception of the Downlink Data Delivery Status. In block1226, the UE responds to the target DU with an RRCReconfigurationComplete message. In block1228, the target DU sends an UL RRC MESSAGE TRANSFER message to the source CU to convey the received RRCReconfigurationComplete message. Downlink packets are sent to the UE and/or uplink packets are sent from the UE, which are forwarded to the source CU through the target DU.

In block1230, for a DAPS handover, the target CU sends the Handover Success message to the source CU to inform that the UE has successfully accessed the target cell. In return, the source CU sends the SN Status Transfer message in block1232for DRBs configured with DAPS for data forwarding to the target CU.

In block1234, the target CU decides to release the source cell connection. The target CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU, which includes a generated RRCReconfiguration message including a DAPS-SourceRelease information element (IE) to indicate the release of source cell connection. The UE CONTEXT MODIFICATION REQUEST message may include an indication to indicate the source DU that a DAPS HO is to be completed or source cell is to be released (e.g. set the value of DAPS HO indication to “completion/release/stop”). If the indication is received, the target DU may stop using the DAPS related coordination configuration for the purpose of power and/or resource coordination during DAPS HO, and/or allow multi-TRP operation during DAPS HO (e.g. enable SDM based Single-DCI based multi-TRP via Enhanced TCI States Activation/Deactivation for UE-specific PDSCH MAC CE).

In block1236, the target DU forwards the received RRCReconfiguration message to the UE. In block1238, the source DU responds to the target CU with the UE CONTEXT MODIFICATION RESPONSE message. In block1240, the UE responds to the target DU with an RRCReconfigurationComplete message. In block1242, the target DU sends an UL RRC MESSAGE TRANSFER message to the target CU to convey the received RRCReconfigurationComplete message. In block1244, the target CU sends a UE CONTEXT RELEASE COMMAND message to the source CU. In block1246, the source CU releases the UE context and in block1248receives a response from the source DU including a UE CONTEXT RELEASE COMPLETE message. In alternative embodiments, the order of blocks1232-1248may vary.

The system and process described above may be encoded in a signal bearing medium, a computer readable medium such as a memory, programmed within a device such as one or more integrated circuits, one or more processors or processed by a controller or a computer. That data may be analyzed in a computer system and used to generate a spectrum. If the methods are performed by software, the software may reside in a memory resident to or interfaced to a storage device, synchronizer, a communication interface, or non-volatile or volatile memory in communication with a transmitter. A circuit or electronic device designed to send data to another location. The memory may include an ordered listing of executable instructions for implementing logical functions. A logical function or any system element described may be implemented through optic circuitry, digital circuitry, through source code, through analog circuitry, through an analog source such as an analog electrical, audio, or video signal or a combination. The software may be embodied in any computer-readable or signal-bearing medium, for use by, or in connection with an instruction executable system, apparatus, or device. Such a system may include a computer-based system, a processor-containing system, or another system that may selectively fetch instructions from an instruction executable system, apparatus, or device that may also execute instructions.

A “computer-readable medium,” “machine readable medium,” “propagated-signal” medium, and/or “signal-bearing medium” may comprise any device that includes stores, communicates, propagates, or transports software for use by or in connection with an instruction executable system, apparatus, or device. The machine-readable medium may selectively be, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium. A non-exhaustive list of examples of a machine-readable medium would include: an electrical connection “electronic” having one or more wires, a portable magnetic or optical disk, a volatile memory such as a Random Access Memory “RAM”, a Read-Only Memory “ROM”, an Erasable Programmable Read-Only Memory (EPROM or Flash memory), or an optical fiber. A machine-readable medium may also include a tangible medium upon which software is printed, as the software may be electronically stored as an image or in another format (e.g., through an optical scan), then compiled, and/or interpreted or otherwise processed. The processed medium may then be stored in a computer and/or machine memory.

The illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The illustrations are not intended to serve as a complete description of all of the elements and features of apparatus and systems that utilize the structures or methods described herein. Many other embodiments may be apparent to those of skill in the art upon reviewing the disclosure. Other embodiments may be utilized and derived from the disclosure, such that structural and logical substitutions and changes may be made without departing from the scope of the disclosure. Additionally, the illustrations are merely representational and may not be drawn to scale. Certain proportions within the illustrations may be exaggerated, while other proportions may be minimized. Accordingly, the disclosure and the figures are to be regarded as illustrative rather than restrictive.

One or more embodiments of the disclosure may be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any particular invention or inventive concept. Moreover, although specific embodiments have been illustrated and described herein, it should be appreciated that any subsequent arrangement designed to achieve the same or similar purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all subsequent adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the description.

The phrase “coupled with” is defined to mean directly connected to or indirectly connected through one or more intermediate components. Such intermediate components may include both hardware and software based components. Variations in the arrangement and type of the components may be made without departing from the spirit or scope of the claims as set forth herein. Additional, different or fewer components may be provided.

The above disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments, which fall within the true spirit and scope of the present invention. Thus, to the maximum extent allowed by law, the scope of the present invention is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description. While various embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the invention. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents.