WO2015063964A1 - Resource allocation method, wireless terminal, and non-temporal computer-readable medium - Google Patents

Abstract

A wireless terminal (2) supporting dual connectivity involving bearer splitting in which a first network bearer between the wireless terminal (2) and a core network is split between a first base station (11) and a second base station (12). The wireless terminal (2) allocates uplink resources of a first cell (110), which is managed by the first base station (11), to a plurality of logical channels, with consideration to the quantity of uplink resources in a second cell (120), which is managed by the second base station (12), that can be allocated to a first logical channel of the first network bearer. The plurality of logical channels include the first logical channel, and a second logical channel of a second network bearer that only transmits at the first cell (110) and is not subjected to bearer splitting. Thus, a resource allocation process for producing an uplink MAC PDU that is effective with respect to, for example, dual connectivity involving bearer splitting, can be provided.

Description

Resource allocation method, wireless terminal, and non-transitory computer-readable medium

This application relates to a wireless communication system in which a plurality of base stations communicate with the same wireless terminal in each cell.

3GPP Long Term Evolution (LTE) and wireless terminals (User Equipment: UE) and 3GPP Long Term Evolution (LTE) to improve the degradation of communication quality due to the rapid increase in mobile traffic in recent years ) Is specifying carrier aggregation (Carrier Aggregation: CA) function for communication using a plurality of cells. In addition, the cell which UE can use by CA is limited to the several cell of 1 eNB (that is, the several cell operated or managed by eNB). The cell used by the UE in the CA is a primary cell (Primary cell: PCell) that is already used as a serving cell at the time of starting the CA, and a secondary cell (Secondary cell: SCell) that is additionally or subordinately used. are categorized. PCell sends and receives Non-Access-Stratum (NAS) mobility information (NAS-mobility information) and security information (security input) during (re) establishment of wireless connection (RRC-Connection-Establishment, RRC-Connection-Re-establishment) ( (See Section 7.5 of Non-Patent Document 1).

In CA, the SCell configuration information transmitted from the eNB to the UE includes SCell (between UE) common radio resource configuration information (RadioResourceConfigCommonSCell) and SCell (per UE) dedicated radio resource configuration information (RadioResourceConfigDedicatedSCell). The latter mainly indicates individual configuration (PhysicalConfigDedicated) of the physical layer. When cells (carriers) with different transmission timings (TimingdvAdvance: TA) are aggregated in the uplink, Medium Access Control (MAC) sublayer configuration information (MAC-MainConfigSCell) is also transmitted from the eNB to the UE. The MAC sublayer setting information includes only the TA Group (TAG) index (STAG-Id) indicating the set of cells having the same TA (see Section 5.3.10.4 of Non-Patent Document 2). Other MAC sublayer settings are common to PCell and SCell.

Currently, in LTE standardization, dual connectivity, in which a UE performs communication using a plurality of cells of a plurality of eNBs when a heterogeneous network (HetNet) environment is mainly assumed (Non-patent Document 3). See). Dual Connectivity is each radio resource (ie cell) provided (ie managed) by the main base station (master base station, Master eNB: MeMe) and sub-base station (secondary base station, Secondary eNB: SeNB). Alternatively, the UE performs communication using the carrier at the same time. Dual Connectivity enables inter-eNB CA in which a UE aggregates a plurality of cells managed by different eNBs. Further, Dual Connectivity is also called inter-node radio resourceUEaggregation from the viewpoint that the UE aggregates a plurality of radio resources managed by different nodes. MeNB is connected to SeNB through an inter-base station interface called Xn. The MeNB holds a connection (S1-MME) with a mobility management device (Mobility Management Entity: MME) of a core network (Evolved Packet Core: EPC) for a UE that executes Dual Connectivity. Therefore, the MeNB can be called a UE mobility management point (or mobility anchor). For example, MeNB is Macro eNB, and SeNB is Pico eNB or Low Power Node (LPN).

Furthermore, in Dual Connectivity, bearer splitting (Bearer Split) in which the network bearer (EPS bearer) is split into MeNB and SeNB is also being studied. In this specification, a network bearer (EPS Bearer) is a virtual set between a UE and an end point of a core network (EPC) (that is, P GW (Packet Data Network Gateway)) for each service received by the UE. Connection. In one alternative of bearer division (alternative), for example, both a radio bearer (Radio Bearer: RB) passing through a MeNB cell and a radio bearer passing through a SeNB cell are mapped to one network bearer. The radio bearer (RB) here refers mainly to a data radio bearer (Data DRB). Bearer division is expected to contribute to further improvement of user throughput.

3GPP TS 36.300 V11.5.0 (2013-03), “3rd Generation Partnership Project, Technical Technical Specification Group Radio Access Network, Evolved Universal Terrestrial Radio Access, E-UTRA, Evolved Universal Terrestrial, Radio Access Access ; Stage 2 (Release 11) ”, March 2013 3GPP TS 36.331 V11.4.0 (2013-06), “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification (RRC); , June 2013 3GPP TR 36.842 V0.2.0 (2013-05), “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Study on Cell, Enhancement and E-TRA Higher layer aspects (Release 12) ”, May 2013

In LTE, the UE generates an uplink (UL) Medium Access Control Protocol Data Unit (MAC PDU) that is transmitted using an available resource (Uplink grant) allocated from the eNB. A MAC-PDU is also called a transport block. In the generation of a UL MAC PDU, a plurality of set logical channels are multiplexed into one MAC PDU. At this time, the QoS of each EPS bearer set for the uplink must be guaranteed. Therefore, the UE generates a UL-MAC-PDU according to a Logical-Channel-Prioritization (LCP) procedure. In the Logical Channel Prioritization (LCP) procedure, each logical channel is given a priority and Prioritized Bit Rate (PBR). PBR is a bit rate provided to a logical channel before any resources are allocated to a logical channel with a lower priority. PBR is set for each logical channel by the eNB. In the LCP procedure, first, all logical channels are guaranteed resource allocation corresponding to PBR in descending order of priority. Next, even if PBR is provided for all logical channels and there are still available resources, the logical channel data disappears or allocated resources in order from the logical channel data with the highest priority. Resources are allocated until exhausted.

However, in Dual Connectivity with bearer division, it is considered that independent Radio Resource Management (RRM), for example, MAC scheduling, is performed in MeNB and SeNB. Therefore, the LCP procedure described above may also be executed independently in the MeNB and SeNB. Then, logical channels (or EPS bearer, radio bearer) that are not subject to bearer division and transmitted only by PCell, and logical channels (or EPS bearer, radio bearer) that are subject to bearer division and transmitted by PCell and SCell. ) May cause unfairness in allocated resources (ie, effective bit rate). In other words, there is a possibility that the resource allocation balance is lost between the logical channel that is not subject to bearer splitting and the logical channel that is subject to bearer splitting, and as a result, the LCP procedure may not function as intended.

Accordingly, one of the objectives that the embodiments disclosed herein attempt to achieve is that a resource allocation procedure (ie, LCP) for generating an uplink MAC PDU that is effective for Dual Connectivity with bearer splitting. Improved procedure). Other objects or problems and novel features will become apparent from the description of the present specification or the accompanying drawings.

In one embodiment, a resource allocation method performed in a wireless terminal that supports dual connectivity with bearer division in which a first network bearer between a wireless terminal and a core network is divided into first and second base stations, Managed by the first base station in consideration of the amount of uplink resources that can be allocated to the first logical channel of the first network bearer in the second cell managed by the second base station Determining the allocation of the uplink resources of the first cell to the plurality of logical channels. Here, the plurality of logical channels include the first logical channel and the second logical channel of the second network bearer that is transmitted only in the first cell without being subjected to bearer division.

In one embodiment, the wireless terminal includes a control unit and a data processing unit. The control unit is configured to control dual connectivity with bearer division in which a first network bearer between the wireless terminal and a core network is divided into first and second base stations. The data processing unit takes into account the amount of uplink resources that can be allocated to the first logical channel of the first network bearer in the second cell managed by the second base station, and The first cell uplink resource managed by one base station is configured to determine an allocation for a plurality of logical channels. Here, the plurality of logical channels include the first logical channel and the second logical channel of the second network bearer that is transmitted only in the first cell without being subjected to bearer division.

In one embodiment, the program includes a group of instructions (software code) for causing the computer to perform the resource allocation method described above when read by the computer.

In one embodiment, a wireless communication system includes a first base station that manages a first cell, a second base station that manages a second cell, and a wireless terminal. The wireless terminal supports dual connectivity with bearer division in which a first network bearer between the wireless terminal and a core network is divided into the first base station and the second base station. Furthermore, the wireless terminal considers the amount of uplink resources that can be allocated to the first logical channel of the first network bearer in the second cell, and then the uplink resource of the first cell. Configured to determine assignments for a plurality of logical channels. Here, the plurality of logical channels include the first logical channel and the second logical channel of the second network bearer that is transmitted only in the first cell without being subjected to bearer division.

According to the above-described embodiment, it is possible to provide a resource allocation procedure (that is, an improvement of the LCP procedure) for generating an uplink MAC PDU effective for Dual Connectivity with bearer division.

It is a figure which shows an example of the user plane protocol stack of the LTE layer 2 regarding Dual connectivity with bearer division. It is a figure which shows the other example of the user plane protocol stack of the LTE layer regarding the Dual connectivity with bearer division. It is a figure which shows an example of the user plane interface protocol stack of the uplink direction of LTE layer regarding Dual interface with bearer division. It is a figure which shows the other example of the user plane interface protocol stack of the uplink direction of LTE layer 2 regarding Dual interface with bearer division. 1 is a diagram illustrating a configuration example of a radio communication system according to first to fifth embodiments. FIG. It is a flowchart which shows an example of the resource allocation method which concerns on 1st Embodiment. It is a flowchart which shows an example of the resource allocation method which concerns on 2nd Embodiment. It is a conceptual diagram which shows the example of a production | generation of uplink MAC PDU when bearer division is not performed. It is a conceptual diagram which shows the example of a production | generation (comparative example) of uplink MAC PDU when bearer division | segmentation is performed. It is a conceptual diagram which shows the production | generation example (example of 2nd Embodiment) of uplink MAC PDU when bearer division | segmentation is performed. It is a flowchart which shows an example of the resource allocation method which concerns on 3rd Embodiment. It is a conceptual diagram which shows the production | generation example (example of 3rd Embodiment) of uplink MAC PDU when bearer division | segmentation is performed. It is a conceptual diagram which shows the production | generation example (example of 3rd Embodiment) of uplink MAC PDU when bearer division | segmentation is performed. It is a conceptual diagram which shows the production | generation example (example of 4th Embodiment) of uplink MAC PDU when bearer division | segmentation is performed. It is a figure which shows an example of the user plane interface protocol stack of the uplink direction of LTE layer regarding Dual interface with bearer division. It is a block diagram which shows the structural example of MeNB which concerns on 1st-5th embodiment. It is a block diagram which shows the structural example of SeNB which concerns on the 1st-5th embodiment. FIG. 6 is a block diagram showing a configuration example of a UE according to the first to fifth embodiments.

Hereinafter, specific embodiments will be described in detail with reference to the drawings. In each drawing, the same or corresponding elements are denoted by the same reference numerals, and redundant description is omitted as necessary for clarification of the description.

<First Embodiment>
First, some examples of Dual Connectivity with bearer division targeted by a plurality of embodiments including this embodiment will be described. 1A and 1B show two alternatives of the user plane protocol stack in the downlink direction of LTE layer 2 for Dual Connectivity with bearer splitting. In bearer division, a network bearer (EPS bearer) set between a UE and an end point (that is, P-GW) of a core network (EPC) is divided into MeNB 11 and SeNB 12. 1A and 1B, EPS bearer # 2 is divided into MeNB11 and SeNB12. EPS bearer # 1 shown in FIG. 1A and FIG. 1B is a normal bearer that is not subject to bearer division, and is therefore mapped one-to-one with a radio bearer passing through the cell of MeNB 11.

In the plans of FIG. 1A and FIG. 1B, one data radio bearer (DRB) mapped one-on-one to EPS bearer # 2 is a Layer 2 Packet Data Convergence Protocol (PDCP) sublayer or Radio Link Control (RLC). It is divided into MeNB11 and SeNB12 in either the sublayer or the MAC sublayer. Specifically, in the plan of FIG. 1A, the PDCP entity of MeNB 11 terminates S1-U of EPS bearer # 2. In other words, one S1 bearer and one data radio bearer (DRB) mapped to EPS bearer # 2 are terminated in the PDCP sublayer of MeNB11. Furthermore, in the plan of FIG. 1A, MeNB11 and SeNB12 have independent RLC entities for bearer division, and one DRBDR (or PDCP bearer) terminated at MeNB11 is the RLC bearer of MeNB11 and SeNB12. Divided into RLC bearers. Here, the PDCP bearer means a connection terminated in the PDCP sublayer of the eNB and UE. The PDCP bearer can also be called PDCPPDProtocol Data Unit (PDCP PDU). In the example of FIG. 1A, there is one PDCP bearer for divided EPS bearer # 2, and this one PDCP bearer is terminated at MeNB11 and UE2. On the other hand, the RLC bearer means a connection terminated at the RLC sublayer of the eNB and UE. An RLC bearer can also be referred to as an RLC-PDU or logical channel. In the example of FIG. 1, there are two independent RLC bearers for EPS bearer # 2, one terminated at MeNB11 and UE2, and the other terminated at SeNB12 and UE2. Therefore, in the architecture of FIG. 1A, UE2 requires two independent RLC entities for the split EPS bearer # 2.

In the plan of FIG. 1B, similar to the plan of FIG. 1A, the PDCP entity of MeNB 11 terminates S1-U of EPS の bearer # 2. Further, regarding the EPS bearer # 2 to be divided, the MeNB 11 has a master RLC entity, and the SeNB 12 has a slave RLC entity. In the plan of FIG. 1B, UE2 only needs one RLC entity for EPS bearer # 2 to be split. On the downlink, the SeNB 12 slave RLC entity receives RLC PDUs already assembled by the master RLC entity and assigned to the slave RLC for transmission from the MeNB 11 master RLC entity.

Here, from the viewpoint of the conventional Carrier Aggregation (CA), the cell of MeNB 11 can be called PCell and the cell of SeNB 12 can be called SCell. This will be described below based on this. However, the application range of the present embodiment is not limited to this. For example, when a wireless terminal (UE) performs dual connectivity, and performs CA (Intra-SeNB CA) on a plurality of cells of SeNB 12 (that is, at least a plurality of downlink Component Carrier (CC)), the target of the CA One of the SeNB12 cells to be used may be positioned as PCell, or may be positioned as a pseudo PCell (Pseudo PCell) such as PCell. The pseudo PCell (Pseudo PCell) can also be called AnchorAncell, Master cell, Control cell, etc. The former (PCell of SeNB12) has the same role as the PCell in the conventional CA in the CA of the SeNB12 cell. In the PCell of SeNB 12, for example, SCell configuration and SCell activation / deactivation by eNB (SeNB) for CA, Radio Link Monitoring (RLM) / Radio Link Failure (RLF) detection by UE, and the like are performed. Also, the UE transmits L1 / L2 control information (eg, CQI, CSI, HARQ feedback, Scheduling Request) on the uplink control channel (PUCCH), Contention-based Random Access Channel (RACH) (Preamble) transmission, A response to the RACH Preamble (Random Access Response (RAR)) may be received. The latter (Pseudo PCell of SeNB12) has a role as a cell having a PCell function related to control of User Plane (UP) in a conventional CA. In SeNB12 Pseudo PCell, for example, UE transmits L1 / L2 control information on uplink control channel (PUCCH), Contention-based RACH (Preamble) transmission, reception of RACH Preamble response (RAR), etc. You may go. Further, in the UE, there may be no vertical relationship (PCell and SCell) or master-slave relationship (Master and Slave) between the cell of MeNB11 and the cell of SeNB12.

It should be noted that the Dual Connectivity connectivity user plane protocol stack with bearer splitting is not limited to the plans in FIGS. 1A and 1B. In bearer division, for example, one network bearer (EPS bearer) may be mapped to two radio bearers. 1A and 1B, EPS bearer # 2 is mapped to both a radio bearer (RB) that passes through the cell (PCell) of MeNB11 and a radio bearer that passes through the cell (SCell) of SeNB12. In this specification, for convenience of explanation, a radio bearer that passes through the cell (PCell) of the MeNB 11 is designated as Primary RB (P-RB), and a radio bearer (RB) that passes through the cell (SCell) of the SeNB is designated as Secondary RB (S-RB). It is defined as Since the target of bearer division is basically a data radio bearer (DRB), P-RB and S-RB can also be called P-DRB and S-DRB. For example, MeNB11 may terminate S1-U of EPS bearer # 2, and MeNB11 and SeNB12 may each have an independent PDCP entity. Furthermore, the downlink S1-U packet stream of EPS bearer # 2 may be split into a PDCP entity of MeNB11 and a PDCP entity of SeNB12 in a new layer above the PDCP entity of MeNB11. In this case, there are two independent PDCP bearers for EPS bearer # 2, one terminated at MeNB11 and UE2, and the other terminated at SeNB12 and UE2.

The user layer protocol stack in the uplink direction of LTE layer 2 related to Dual connectivity with bearer division is the same as that in the downlink direction described above. FIG. 2A and FIG. 2B show two proposals of the user plane / protocol stack in the uplink direction in the UE 2, and correspond to FIG. 1A and FIG. In the plan of FIG. 2A, one PDCP entity of UE2 receives user data of EPS bearer # 2 from an upper layer. The PDCP entity of UE2 divides and sends the PDCP PDUs to the MAC entity for transmission to MeNB11 and the MAC entity for transmission to SeNB12. In other words, PDCP PDU (that is, PDCP bearer) is divided into an RLC bearer transmitted to MeNB 11 and an RLC bearer transmitted to SeNB 12. In the plan of FIG. 2B, as in the plan of FIG. 1B, UE2 has a master RLC entity (RLC entity for MeNB 11 on the left side of FIG. 2B) and a slave RLC entity (RLC entity for SeNB 12 on the right side of FIG. 2B). Have The slave RLC entity of UE2 receives from the master RLC entity the RLCsPDUs already assembled by the master RLC entity and assigned to the slave RLC for transmission. The scheme of FIGS. 2A and 2B is an example, and other architectures may be employed. For example, in the plans of FIGS. 2A and 2B, UE 2 has a MAC entity for MeNB 11 and a MAC entity for SeNB 12, but there may be only one MAC entity for uplink transmission. .

FIG. 3 shows a configuration example of a wireless communication system according to some embodiments including this embodiment. The wireless communication system includes a wireless access network (Radio Access Network: RAN) 1, a wireless terminal (UE) 2, and a core network 3. In EPS, RAN1 is Evolved UMTS Terrestrial Radio Access Network (E-UTRAN), and Core Network 3 is Evolved Packet Core (EPC). The E-UTRAN 1 includes base stations (evolved NodeB: eNB) 11 and 12. The eNB 11 manages the cell 110, and the eNB 12 manages the cell 120. UE2 connects to eNB11 and 12 by radio | wireless access technology. The EPC 3 is accessed from the UE 2 via the E-UTRAN 1 and provides a connection service (for example, an Internet Protocol (IP) connection service) to the external network (Packet Data Network: PDN). FIG. 3 shows a HetNet environment. Specifically, the cell 110 shown in FIG. 3 has a wider coverage than the cell 120. FIG. 3 shows a hierarchical cell configuration in which the cell 120 is arranged in the cell 110. However, the cell configuration shown in FIG. 3 is only an example. For example, cells 110 and 120 may have similar coverage. In other words, the wireless communication system according to the present embodiment may be applied to a homogeneous network environment.

The E-UTRAN 1 and UE 2 of this embodiment support Dual Connectivity with bearer division. That is, UE2 may use cell 120 of eNB (that is, SeNB) 12 as a secondary cell (SCell), while using cell 110 of eNB (that is, MeNB) 11 as a primary cell (PCell). it can. UE2 can receive EPS bearer data subject to bearer splitting via PCell 110 and SCell 120, or transmit split EPS bearer data via PCell 110 and SCell 120, or both .

In order to improve the uplink MAC 改善 PDU generation procedure (that is, LCP procedure) when Dual Connectivity with bearer division is performed, UE2 operates as described below. When bearer splitting is performed, the logical channel of EPS bearer (hereinafter referred to as split EPS bearer) that is the target of bearer splitting and transmitted by both PCell110 and SCell120, and is not subject to bearer splitting, only by PCell110 There is a possibility that the logical channel of the transmitted EPS bearer (hereinafter referred to as non-division EPS bearer) is transmitted in the uplink. At this time, the UE 2 generates a MAC PDU (referred to as a first MAC PDU) transmitted by the PCell 110 (namely, an LCP procedure) and a MAC PDU (referred to as a second MAC PDU) transmitted from the SCell 120. If the generation procedure is executed independently, the data of the logical channel of the divided EPS bearer may be excessively transmitted. In other words, there is an unfairness in the allocated resources (ie effective bit rate) between the undivided EPS 分割 bearer logical channel and the split EPS bearer logical channel, resulting in the LCP procedure not functioning as intended. there is a possibility.

In order to deal with this problem, the UE 2 according to the present embodiment considers the amount of uplink resources that can be allocated to the logical channel of the divided EPS bearer in the SCell 120, and then determines the logical channel of the divided EPS bearer and the non-divided EPS bearer. It operates to determine resource allocation in the PCell 110 for a plurality of logical channels including the logical channels. Specifically, when the UE 2 can sufficiently allocate uplink resources to the logical channel of the divided EPS bearer in the SCell 120, according to the normal LCP procedure, the UE2 is assigned to the logical channel of the divided EPS に bearer in the PCell 110. The resources that should be reduced may be reduced, and the reduced resources may be allocated to the logical channel of the non-divided EPS bearer. Note that allocating resources to logical channels means multiplexing data stored in the logical channel transmission buffer into MAC PDUs (transport blocks). With this operation, the uplink resource allocation in the PCell 110 can be adjusted or corrected based on the allocation status of the uplink resource to the logical channel of the divided EPS bearer in the SCell 120. Accordingly, it is possible to suppress the occurrence of unfairness in the allocated resources (that is, effective bit rate) between the logical channel of the non-divided EPS bearer and the logical channel of the divided EPS bearer.

Hereinafter, some examples of uplink resource allocation by UE 2 will be described. In the first example, when the uplink resource of the PCell 110 is allocated, the UE 2 that allocates the uplink resource of the divided EPS１２０bearer to the logical channel of the divided EPS bearer increases as the uplink resource amount of the SCell 120 that can be assigned to the logical channel of the divided EPS bearer increases. The amount of uplink resources may be reduced. According to such an operation, it is possible to control so that the total resource amount allocated to the logical channel of the divided EPS bearer in the PCell 110 and the SCell 120 does not increase excessively. Therefore, it is possible to suppress allocation of excessive uplink resources to the divided EPS bearer.

In the second example, UE2 may attempt to reserve the prioritized BitRate (PBR) resource of the split EPS bearer logical channel in preference to the uplink resource of SCell120 rather than the uplink resource of PCell110. . Then, UE2 uses the PBR resource of the logical channel of the divided EPS bearer or the reference resource amount calculated based on the PBR resource (for example, a value obtained by multiplying the PBR resource by a predetermined weight) in the uplink cell of SCell120. The shortage that could not be secured from the resources may be secured from the uplink resources of the PCell 110. According to such an operation, excess resources exceeding the PBR resource are preferentially allocated in the PCell 110 to the logical channel of the split bearer while guaranteeing the PBR resource of the split bearer logical channel in the entire PCell 110 and the SCell 120. Can be prevented. Therefore, it is possible to suppress allocation of excessive uplink resources to the divided EPS bearer.

In the third example, when allocating uplink resources of the PCell 110, the UE 2 may try to allocate uplink resources of the PCell 110 to a plurality of logical channels according to a normal LCP procedure. Here, the plurality of logical channels include a logical channel of divided EPS bearer and a logical channel of non-divided EPS bearer. Then, if there is untransmitted data in the logical channel of the non-divided EPS bearer after the trial (that is, transmission data remains in the transmission buffer), UE2 assigned to the logical channel of the divided EPS bearer in the trial The resource amount may be reduced by a first amount and this first amount may be reallocated to the logical channel of the non-divided EPS bearer. Here, the first amount may be a fixed amount, or may be increased or decreased according to the amount of untransmitted data (that is, the amount of data remaining in the transmission buffer) of the logical channel of the non-divided EPS） bearer. . This operation is particularly effective when the logical channel of the non-divided EPS bearer is given a higher priority than the logical channel of the divided EPS bearer. According to such an operation, the LCP procedure in the PCell 110 is corrected, and the PCell 110 can prioritize the resource allocation for the logical channel of the non-divided EPS bearer rather than securing the PBR resource of the logical channel of the divided EPS bearer. Therefore, it is possible to suppress allocation of excessive uplink resources to the divided EPS bearer.

Note that the redistribution of the first amount in the third example described above may be performed in consideration of the uplink resource amount of the SCell 120 allocated to the logical channel of the divided EPS bearer. For example, the uplink resource amount of the SCell 120 assigned to the logical channel of the divided EPS bearer is the uplink resource of the PCell 110 assigned to the logical channel of the divided EPS bearer in the trial (that is, the trial of resource assignment of the PCell 110). It may be performed on condition that the amount exceeds a predetermined amount than the amount. Alternatively, the redistribution of the first amount indicates that the uplink resource amount of the SCell 120 allocated to the logical channel of the divided EPS bearer is equal to or higher than the prioritized Bit Rate (PBR) resource of the logical channel of the divided EPS bearer. It may be performed as a condition.

FIG. 4 is a flowchart showing an example of a procedure for generating a MAC-PDU when bearer division is performed by UE2 according to the present embodiment. In step S11, UE2 receives uplink permission (uplink | grants) from both the cell 110 (PCell110) of MeNB11, and the cell 120 (SCell120) of SeNB12. The uplink grant indicates an uplink resource assigned by UE2 from MeNB11 or SeNB12. In step S12, UE2 (specifically, the MAC entity associated with SCell120) is a MAC PDU (referred to as a second MAC PDU) transmitted in SeNB12 cell 120 in accordance with uplink permission in SeNB12 cell 120. To generate uplink resources for at least one logical channel to be transmitted in the cell 120 of the SeNB 12 (including the logical channel of the split EPS bearer).

In step S13, UE2 (specifically, the MAC entity associated with PCell 110), according to the uplink grant (uplink grant) in the cell 110 of MeNB11, the MAC PDU (the first PDU) transmitted in the cell 110 of MeNB11. In order to generate a MAC PDU), uplink resources are allocated to at least one logical channel (including the divided EPS bearer logical channel) to be transmitted in the cell 110 of the MeNB11. Here, the MAC entity of UE2 associated with the cell 110 of the MeNB 11 is the uplink resource of the cell 120 of the SeNB 12 allocated to the logical channel of the divided EPS bearer when the uplink resource of the cell of the MeNB 11 is allocated. Consider the amount.

Specific examples or modifications of the uplink resource allocation procedure (MAC PDU generation procedure) by the UE 2 described in this embodiment will be described in the second to fifth embodiments.

<Second Embodiment>
In the present embodiment, a specific example or modification of the uplink resource allocation procedure by the UE 2 will be described. A configuration example of the wireless communication system according to the present embodiment is the same as that shown in FIG.

FIG. 5 is a flowchart showing an example of an uplink resource allocation procedure by the UE 2 according to the present embodiment. In step S21, UE2 receives uplink permission (uplink grants) from both cell 110 (PCell110) of MeNB11 and cell 120 (SCell120) of SeNB12. In step S22, UE2 follows the normal or modified LCP procedure, at least one logical channel (segmented EPS bearer logical channel) transmitted in cell 120 of SeNB12 the uplink resources allowed in cell 120 of SeNB12. Including). In addition, when only the data of the divided EPS の bearer logical channel is transmitted in the cell 120 of the SeNB 12, all resources allocated in the cell of the SeNB 12 are simply allocated to the data of the logical channel without executing the LCP algorithm. May be.

In steps S23 to S25, UE2 executes the first round of the modified LCP procedure for the uplink resources of cell 110 of MeNB11. Here, the first round of the LCP procedure means a process of securing PBR resources in order of priority for a plurality of logical channels. First, in step S23, UE2 allocates a PBR resource to the logical channel of the non-division EPS bearer bearer given higher priority than the logical channel of the divided EPS bearer. In step S24, UE2 determines whether all the PBR resources of the logical channel of the divided EPS bearer have been secured in the cell 120 of SeNB12.

When all or a part of the PBR resources of the logical channel of the divided EPS bearer is not secured in the cell 120 of the SeNB 12 (NO in step S24), the UE 2 has a shortage of PBR resources not secured in the cell 120 of the SeNB 12 Is secured from the uplink resource of the cell 110 of the MeNB 11 (step S25). On the other hand, when all the PBR resources of the logical channel of the divided EPS bearer have been secured in the cell 120 of the SeNB 12 (YES in step S24), the UE 2 does not perform step S25. In other words, if all the PBR resources of the logical channel of the divided EPS に て bearer have been reserved in the cell 120 of the SeNB 12, UE2 reserves the redundant PBR resource for the logical channel of the divided EPS bearer in the cell 110 of the MeNB11. Deter.

In step S26, UE2 performs the second round of the LCP procedure for the remaining uplink resources of cell 110 of MeNB11. Here, the second round of the LCP procedure means a process of assigning remaining resources to a plurality of logical channels in order of priority after the end of the first round of assigning PBR resources.

In steps S24 and S25, the shortage of the reference resource amount calculated based on the PBR2 of LCHL # 2 that cannot be secured from the uplink resource of the cell 120 of the SeNB 12 is the uplink resource of the cell 110 of the MeNB 11 May be secured. The reference resource amount may be, for example, a value obtained by multiplying PBR2 of LCH # 2 by a predetermined weight. Further, the reference resource amount may be a value obtained by subtracting a predetermined value from PBR2 of LCH # 2, or may be a value obtained by adding a predetermined value to PBR2 of LCH # 2.

Subsequently, a specific example of resource allocation based on the procedure shown in FIG. 5 will be described with reference to FIGS. 6A to 6C. FIG. 6A is a conceptual diagram illustrating an example of generation of an uplink MAC-PDU in the MeNB 11 (PCell 110) when bearer division is not performed.

Here, the normal LCP procedure will be described more strictly. The UE manages a variable Bj for each logical channel j. Bj is initialized to zero when logical channel j is established and is the product of the prioritized bit rate (PBR) and transmission time interval (TTI) period (ie, PBR x TTI duration) for each Transmission Time Interval (TTI) Is incremented only by However, the value of Bj cannot exceed the bucket size. If the value of Bj is larger than the bucket size of logical channel j, the value of Bj is set to the bucket size. The bucket size of the logical channel j is equal to the product of PBR (eg 64 kbps) and Bucket Size Duration (BSD) (eg 50 ms) (that is, PBR × BSD). PBR and BSD are set by higher layers. The UE performs the LCP procedure including the following steps 1 to 3 when performing a new transmission.
Step 1: Resources are allocated in descending order of priority to all logical channels with Bj> 0.
Step 2: The UE decrements Bj by the total size of MAC SDUs provided to logical channel j in Step 1.
Step 3: If resources still remain, all logical channels are either logical channel data or uplink grants (UL grants) according to a strict priority descending order (regardless of the value of Bj) Receive resources until you run out.

FIG. 6A shows an example of multiplexing data of two logical channels (that is, LCH # 1 and LCH # 2) into available resources (MAC PDU payload) indicated in the uplink grant from MeNB11 (uplink grant). Show. Therefore, in the example of FIG. 6A, the above-described normal LCP procedure is executed for two logical channels (LCH # 1 and LCH # 2). LCH # 1 is given the highest priority and PBR1. LCH # 2 is given second priority (second priority) and PBR2. According to the uplink PBR procedure specified in LTE, resources up to B1 are secured for LCH # 1 with the highest priority first, and then resources up to B2 are secured for LCH # 2. Is done. B1 is a variable incremented by the product of PBR1 of LCHL # 1 and the TTI period for each TTI, and B2 is a variable incremented by the product of PBR2 of LCH # 2 and the TTI period for each TTI. After that, the remaining space of the available resources (MAC payload) is the LCH # 1 until the LCH # 1 data with the highest priority is exhausted or the resource space (MAC payload) is exhausted. Filled with data.

FIG. 6B shows a case where bearer splitting is performed for EPS bearer corresponding to logical channel LCH # 2. However, FIG. 6B is not an example based on the procedure shown in FIG. 5, but is a comparative example described for comparison with FIG. 6C described later. The logical channel set to UE2 in SCell120 is only LCH # 2. Therefore, the uplink resource of the SCell 120 that is permitted from the SeNB 12 to the UE 2 can be mainly used to transmit data of the logical channel LCH # 2. However, in the example of FIG. 6B, the PBR set for the logical channels LCH # 1 and LCH # 2 remains the same as the example of FIG. 6A (that is, PBR1 and PBR2), and the logical channel LCH # of the divided EPS bearer. 2, the same PBR2 is set in each of the PCell 110 and the SCell 120. Therefore, in the example of FIG. 6B, the bit rate of the logical channel LCH # 2 to which the second priority is given is higher than the bit rate of the logical channel LCH # 1 to which the highest priority is given. Yes. Such a state represents a state in which the balance of resource allocation between the logical channel LCH # 1 that is not subject to bearer splitting and the logical channel LCH # 2 that is subject to bearer splitting is lost, and is intended by the LCP procedure. It means that it is not functioning on the street.

FIG. 6C shows a specific example of resource allocation based on the procedure shown in FIG. The modified LCP procedure shown in FIG. 6C can eliminate the less preferred situation shown in FIG. 6B. First, a general description of the modified LCP procedure applied to the example shown in FIG. 6C. The modified LCP procedure is performed in the following steps. The following step A corresponds to the first round of the LCP procedure in the SCell 120, and step B corresponds to the second round of the LCP procedure in the SCell 120. Step 1 corresponds to the first round of the modified LCP procedure in PCell 110. Step 3 corresponds to the second round of the LCP procedure in PCell 110.

Step A: Resources of SCells (for example, small cells) are allocated in descending order of priority to all “logical channels for which bearer division is set (logical channels of divided EPS Bearer)” where Bj> 0.
• Step B: If “SCell resources” still remain, all logical channels follow the exact priority descending order until either the logical channel data or the uplink grant (UL grant) is exhausted. Get offered.
Step C: The UE decrements Bj by the total size of MAC SDUs provided to logical channel j in steps A and B.
Step 1: PCell (for example, macro cell) resources are allocated in descending order of priority to all logical channels where Bj> 0.
Step 2: The UE decrements Bj by the total size of MAC SDUs provided to logical channel j in Step 1.
• Step 3: If “PCell resources” still remain, all logical channels follow the exact priority descending order until either the logical channel data or uplink grant (UL grant) is exhausted. Get offered.

Note that when only the data of the logical channel of the divided EPS bearer is transmitted in the SCell, the above step A may be skipped.

Subsequently, a specific example in which the two logical channels LCH # 1 and LCH # 2 shown in FIG. 6C are set will be described.

Step A: In SCell 120, a PBR resource corresponding to B2 is secured for LCH # 2. B2 is a variable that is incremented by the product of PBR2 of LCH # 2 and the TTI period for each TTI.

Step B: The remaining uplink resources of SCell 120 are allocated to LCH IV # 2.

Step C: UE2 decrements B2 by the total size of MAC SDUs provided to LCH # 2 in SCell120.

Step 1: In the PCell 110, a PBR resource corresponding to B1 is secured for the highest priority LCH 高 い # 1. B1 is a variable that is incremented by the product of PBR1 of LCH # 1 and the TTI period for each TTI. Next, if all (B2) of the PBR resource of LCH # 2 is not secured in SCell120 (that is, when B2> 0), the shortage of PBR resource (B2) of LCH # 2 is Secured from uplink resources. Otherwise (that is, when B2 = 0 or B2 <0), the PCell 110 does not allocate PBR resources for LCH # 2. In the example of FIG. 6C, since all the PBR resources (B2) of LCH # 2 are secured in SCell 120, resource allocation for LCH # 2 is not performed here.

Step 2: UE2 decrements B1 and B2 by the total size of MAC SDUs provided to LCH # 1 and LCH # 2 in SCell 120, respectively.

Step 3: The remaining uplink resources of PCell 110 are initially assigned to LCH IV # 1. If the transmission data of LCH # 1 is exhausted before the remaining uplink resources of PCell 110 are exhausted, the remaining uplink resources of PCell 110 are allocated to LCH # 2. In the example of FIG. 6C, since there are remaining resources even after the transmission data of LCH # 1 is exhausted, the remaining resources are also allocated to LCH # 2.

<Third Embodiment>
In the present embodiment, a specific example or modification of the uplink resource allocation procedure by the UE 2 will be described. A configuration example of the wireless communication system according to the present embodiment is the same as that shown in FIG.

FIG. 7 is a flowchart illustrating an example of an uplink resource allocation procedure by the UE 2 according to the present embodiment. In step S31, UE2 receives uplink permission (uplink | grants) from both the cell 110 (PCell110) of MeNB11, and the cell 120 (SCell120) of SeNB12. In step S32, UE2 tries to allocate the uplink resources allowed in each of cells 110 and 120 to the logical channel according to the normal LCP procedure.

In step S33, UE2 determines whether or not the transmission buffer of the logical channel of the non-divided EPS bearer given higher priority than the divided EPS bearer is empty. In other words, the UE 2 determines whether or not all data of the logical channel of the non-division EPS bearer given higher priority than the division EPS bearer can be transmitted in the cell 110 of the MeNB11. If it is determined in step S33 that transmission is not possible (NO in step S33), UE2 executes the process of step S34. In step S34, UE2 reduces the allocation resource for the logical channel of the divided EPS bearer in the cell 110 of MeNB11 by the first amount ΔB, and reallocates the first amount ΔB to the non-divided EPS bearer logical channel. Note that the redistribution of ΔB is performed in consideration of the uplink resource amount of the cell 120 of the SeNB 12 allocated to the logical channel of the divided EPS bearer. For example, the uplink resource amount of the cell 120 of the SeNB 12 assigned to the logical channel of the divided EPS bearer exceeds a predetermined amount than the uplink resource amount of the cell 110 of the MeNB11 assigned to the logical channel of the divided EPS bearer. It may be performed on condition that there are many.

On the other hand, if it is determined in step S33 that transmission is possible (YES in step S33), UE2 does not perform step S34. In step S35, UE2 confirms the uplink resource allocation to the logical channel group in cells 110 and 120.

Subsequently, a specific example of resource allocation based on the procedure shown in FIG. 7 will be described with reference to FIGS. 8A and 8B. 8A and 8B show an example of transmitting data of two logical channels (that is, LCH # 1 and LCH # 2), as in FIG. 6C. LCH # 1 is given the highest priority and PBR1. LCH # 2 is given second priority (second priority) and PBR2.

In FIG. 8A and FIG. 8B, processing is performed in the order of the following steps 1 to 6. Note that step 1 corresponds to trials of independent LCP procedures in each of the PCell 110 and the SCell 120. Steps 3 and 4 correspond to the modification of the independent LCP procedure in PCell 110 and SCell 120, respectively.

Step 1: As shown in FIG. 8A, UE2 tries an independent LCP procedure in each of PCell 110 and SCell 120. Specifically, UE2 allocates to PCell110 resource amount (TMP_B1) that can be allocated to LCH # 1, PCell 110 resource amount (TMP_B2_CELL1) that can be allocated to LCH # 2, and LCH # 2. The amount of possible SCell 120 resources (TMP_B2_CELL2) is calculated.

Step 2: UE2 determines whether or not all data of LCH IV # 1 can be transmitted in the trial of Step 1. If all the data of LCH # 1 can be transmitted in the trial of Step 1, the process proceeds to Step 6. Otherwise, go to step 3.

Step 3: UE2 determines whether TMP_B2_CELL2 exceeds TMP_B2_CELL1 by more than a predetermined amount. When TMP_B2_CELL2 exceeds the predetermined amount compared with TMP_B2_CELL1, TMP_B2_CELL1 is decreased by a first amount ΔB 量 as shown in FIG. 8B. Otherwise, go to step 6.

Step 4: As shown in FIG. 8B, UE2 additionally allocates the first amount ΔB to LCH８ # 1.

Step 5: When the remaining transmission data size of LCH # 1 is smaller than ΔB, UE2 allocates the remaining resources of PCell110 to LCH # 2. In the example of FIG. 8B, since the remaining transmission data size of LCH # 1 is larger than ΔB, and therefore all of ΔB can be assigned to LCH # 1, no resource is assigned to LCH # 2.

Step 6: UE2 confirms uplink resource allocation to LCH # 1 and LCH # 2 in PCell110 and SCell120.

<Fourth Embodiment>
In the present embodiment, a specific example or modification of the uplink resource allocation procedure by the UE 2 will be described. A configuration example of the wireless communication system according to the present embodiment is the same as that shown in FIG.

FIG. 9 shows a specific example of resource allocation based on the modified LCP procedure according to this embodiment. First, a general description of the modified LCP procedure applied to the example shown in FIG. The modified LCP procedure is performed in the following steps.

Step A: Resources of SCells (for example, small cells) are allocated in descending order of priority to all “logical channels for which bearer division is set (logical channels of divided EPS Bearer)” where Bj> 0.
Step B: The UE decrements Bj by the total size of the MAC SDUs provided to logical channel j in step A.
• Step C: If “SCell resources” still remain, all logical channels follow the exact priority descending order until either the logical channel data or the uplink grant (UL grant) is exhausted. Get offered.
Step 1: PCell (for example, macro cell) resources are allocated in descending order of priority to all logical channels where Bj> 0. However, Bj of logical channel j with bearer division (that is, logical channel j of divided EPS bearer) is multiplied by weight W, and resources are allocated to logical channel j with bearer division based on product Bj * W.
Step 2: The UE decrements Bj by the total size of MAC SDUs provided to logical channel j in Step 1.
• Step 3: If “PCell resources” still remain, all logical channels follow the exact priority descending order until either the logical channel data or uplink grant (UL grant) is exhausted. Get offered.

Subsequently, a specific example in which the two logical channels LCHL # 1 and LCH # 2 shown in FIG. 9 are set will be described below.

Step A: In SCell 120, a PBR resource corresponding to B2 is secured for LCH # 2. B2 is a variable that is incremented by the product of PBR2 of LCH # 2 and the TTI period for each TTI.

Step B: UE2 decrements B2 by the total size of MAC SDUs provided to LCH # 2 in SCell120.

Step C: Remaining uplink resources of SCell 120 are allocated to LCH # 2.

Step 1: In the PCell 110, a PBR resource corresponding to B1 is secured for the highest priority LCH 高 い # 1. B1 is a variable that is incremented by the product of PBR1 of LCH # 1 and the TTI period for each TTI. Next, PBR resources corresponding to the product B2 * W of B2 and weight W of LCH # 2 are secured for LCH # 2. In the example of FIG. 9, the weight W is not less than zero and not more than 1 (0１ <= W <= 1).

Step 2: UE2 decrements B1 and B2 by the total size of MAC SDUs provided to LCH # 1 and LCH # 2 in SCell 120, respectively.

Step 3: The remaining uplink resources of PCell 110 are initially assigned to LCH IV # 1. If the transmission data of LCH # 1 is exhausted before the remaining uplink resources of PCell 110 are exhausted, the remaining uplink resources of PCell 110 are allocated to LCH # 2. In the example of FIG. 9, since the resources of the PCell 110 are exhausted before the transmission data of LCH # 1 is exhausted, no remaining resources are allocated to LCH # 2.

Also with the modified LCP procedure according to the present embodiment, the uplink resource allocation in the PCell 110 can be adjusted or corrected based on the allocation status of the uplink resource to the logical channel of the divided EPS bearer in the SCell 120. Accordingly, it is possible to suppress the occurrence of unfairness in the allocated resources (that is, effective bit rate) between the logical channel of the non-divided EPS bearer and the logical channel of the divided EPS bearer.

<Fifth Embodiment>
In the first to fourth embodiments, the case where there is only one divided EPS bearer has been described for convenience of explanation. However, these embodiments may be applied to a case where a plurality of divided EPS bearers are used simultaneously. The plurality of divided EPS bearers may be split from MeNB 11 into one SeNB 12 or may be split from MeNB 11 into a plurality of SeNBs 12. For example, as illustrated in FIG. 10, one undivided EPS bearer that passes through the PCell 110 and two divided EPS bearers that are divided into the PCell 110 and the SCell 120 may be set.

As described in the second embodiment, UE2 considers uplink resources that can be allocated to logical channels of a plurality of divided EPS bearers (for example, EPS bearers # 2 and # 3) in one or a plurality of SCells 120. Then, the resource allocation in the PCell 110 may be calculated for a plurality of logical channels (for example, EPS bearers # 1 to # 3) including the logical channel of divided EPS 分割 bearer and the logical channel of non-divided EPS bearer.

Further, as described in the third embodiment, the UE 2 transmits the PCell 110 to a plurality of logical channels (for example, EPS bearers # 1 to # 3) including a logical channel of divided EPS bearer and a logical channel of non-divided EPS 分割 bearer. And the uplink resources that can be allocated to the logical channels of a plurality of divided EPS bearers (for example, EPS bearers # 2 and # 3) in SCell120, and finally PCell110 and SCell120 You may calculate the uplink resource allocated to each logical channel by each.

A person skilled in the art who has touched the disclosure of the present specification can extend the uplink resource allocation procedure described in the first to fourth embodiments to a case where a plurality of divided EPS bearers are used simultaneously. Will be easily understood.

In the first to fourth embodiments, the case where one or a plurality of non-divided EPS bearers are set in the PCell 110 has been described for convenience of explanation. However, these embodiments may be applied to a case where one or a plurality of non-divided EPS bearers are set in the SCell 120. In addition, these embodiments may be applied to a case where one or a plurality of non-divided EPS bearers are set in each of the PCell 110 and the SCell 120. For example, one undivided EPS bearer that passes through the SCell120 and one divided EPS bearer that is divided into the PCell110 and the SCell120 may be set. Further, for example, one undivided EPS bearer that passes through the PCell 110, another non-divided EPS bearer that passes through the SCell120, and one divided EPS bearer that is divided into the PCell110 and the SCell120 may be set.

Subsequently, configuration examples of the MeNB 11, the SeNB 12, and the UE 2 according to the first to fifth embodiments described above will be described below. FIG. 11 is a block diagram illustrating a configuration example of the MeNB 11. The radio communication unit 111 receives an uplink signal (uplink signal) transmitted from the UE 2 via an antenna. The reception data processing unit 113 restores the received uplink signal. The obtained received data is transferred to another network node, for example, the Serving （Gateway (S-GW) or MME of the EPC 3, or another eNB via the communication unit 114. For example, the uplink user data received from the UE 2 is transferred to the S-GW in the EPC 3. Further, the control data of the NAS among the control data received from the UE 2 is transferred to the MME in the EPC 3. Further, the reception data processing unit 113 receives the control data transmitted to the SeNB 12 from the communication control unit 115 and transmits it to the SeNB 12 via the communication unit 114.

The transmission data processing unit 112 acquires user data addressed to the UE 2 from the communication unit 114, and performs error correction coding, rate matching, interleaving, and the like to generate a transport channel. Furthermore, the transmission data processing unit 112 adds control information to the transport channel data sequence to generate a transmission symbol sequence. The radio communication unit 111 performs each process such as carrier wave modulation, frequency conversion, and signal amplification based on the transmission symbol sequence to generate a downlink signal, and transmits this to the UE 2. Further, the transmission data processing unit 112 receives the control data transmitted to the UE 2 from the communication control unit 115 and transmits it to the UE 2 via the wireless communication unit 111.

The communication control unit 115 controls Dual Connectivity with bearer division. For example, the communication control unit 115 may generate setting information and control information necessary for dual connectivity with bearer division, and transmit this to the SeNB 12 and the UE 2. Further, the communication control unit 115 may perform layer 1 / layer 2 control of access２stratum in response to receiving the communication status information (or bearer division state information) of the divided EPS bearer from the SeNB 12. Further, the communication control unit 115 may transmit the communication status information (or bearer division state information) of the divided EPS bearer to the SeNB 12 in order to trigger the access stratum layer 1 / layer 2 control in the SeNB 12.

FIG. 12 is a block diagram illustrating a configuration example of the SeNB 12. Functions and operations of the wireless communication unit 121, the transmission data processing unit 122, the reception data processing unit 123, and the communication unit 124 illustrated in FIG. 11 correspond to elements corresponding to the MeNB 11 illustrated in FIG. 11, that is, the wireless communication unit 111. The transmission data processing unit 112, the reception data processing unit 113, and the communication unit 114 are the same.

The communication control unit 125 of the SeNB 12 controls Dual Connectivity with bearer division. The communication control unit 125 may transmit the communication status information (or bearer division state information) of the divided EPS bearer to the MeNB 11 in order to trigger the access stratum layer 1 / layer 2 control in the MeNB 11. Further, the communication control unit 125 may perform layer 1 / layer 2 control of access stratum in response to receiving the communication status information (or bearer division state information) of the divided EPS bearer from the MeNB 11.

FIG. 13 is a block diagram illustrating a configuration example of UE2. The radio communication unit 21 is configured to support Dual Connectivity and perform simultaneous communication in a plurality of cells (PCell110 and SCell120) operated by different eNBs (MeNB11 and SeNB12). Specifically, the radio communication unit 21 receives a downlink signal from the MeNB 11 or the SeNB 12 or both via the antenna. The reception data processing unit 22 restores the reception data from the received downlink signal and sends it to the data control unit 23. The data control unit 23 uses the received data according to the purpose. Further, the transmission data processing unit 24 and the wireless communication unit 21 generate an uplink signal using the transmission data supplied from the data control unit 23 and transmit the uplink signal to the MeNB 11 or the SeNB 12 or both.

The communication control unit 25 of the UE 2 controls Dual Connectivity with bearer division. Based on an instruction from the MeNB 11 or SeNB 12, the communication control unit 25 performs access / stratum layer 1 / layer 2 control on the divided EPS / bearer.

Note that the transmission data processing unit 24 executes the uplink resource allocation procedure described in the first to third embodiments, and performs MAC-to-PDUs (that is, transcoding) transmitted by the PCell 110 and the SCell 120 during bearer division. Port channel or transport block). The MAC PDUs generated by the transmission data processing unit 24 are processed by the PHY layer of the wireless communication unit 21.

<Other embodiments>
The generation processing of MAC PDU including communication control and resource allocation in MeNB11, SeNB12, and UE2 regarding Dual Connectivity with bearer division described in the first to fifth embodiments is an Application Specific Integrated Circuit (ASIC). It may be realized using a semiconductor processing apparatus including: In addition, these processes may be realized by causing a computer system including at least one processor (eg, a microprocessor, a micro processing unit (MPU), or a digital signal processor (DSP)) to execute a program. Specifically, one or a plurality of programs including an instruction group for causing a computer system to execute an algorithm described using a sequence diagram or the like may be created, and the programs may be supplied to the computer.

This program can be stored using various types of non-transitory computer readable media and supplied to a computer. Non-transitory computer readable media include various types of tangible storage media (tangible storage medium). Examples of non-transitory computer-readable media are magnetic recording media (eg flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (eg magneto-optical discs), Compact Disc Read Only Memory (CD-ROM), CD-ROM R, CD-R / W, semiconductor memory (for example, mask ROM, Programmable ROM (PROM), Erasable PROM (EPROM), flash ROM, Random Access Memory (RAM)). The program may also be supplied to the computer by various types of temporary computer-readable media. Examples of transitory computer readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire and an optical fiber, or a wireless communication path.

In the first to fifth embodiments, mainly the LTE system has been described. However, as described above, these embodiments may be applied to a wireless communication system other than the LTE system, for example, 3GPP UMTS, 3GPP2 CDMA2000 system (1xRTT,） HRPD), GSM / GPRS system, or WiMAX system. Good.

Furthermore, the above-described embodiments are merely examples relating to application of the technical idea obtained by the present inventors. That is, the technical idea is not limited to the above-described embodiment, and various changes can be made.

This application claims priority based on Japanese Patent Application No. 2013-227474 filed on Oct. 31, 2013, the entire disclosure of which is incorporated herein.

1 Evolved UTRAN (E-UTRAN)
2 User Equipment (UE)
3 Evolved Packet Core (EPC)
11 Master eNodeB (MeNB)
12 Secondary eNodeB (SeNB)
24 Transmission data processing unit 25 Communication control unit 110 Primary Cell (PCell)
120 Secondary Cell (SCell)

Claims (20)

A resource allocation method performed in a wireless terminal supporting dual connectivity with bearer division in which a first network bearer between a wireless terminal and a core network is divided into first and second base stations,
Managed by the first base station in consideration of the amount of uplink resources that can be allocated to the first logical channel of the first network bearer in the second cell managed by the second base station Determining the allocation of the uplink resources of the first cell to the plurality of logical channels,
The plurality of logical channels include the first logical channel and a second logical channel of a second network bearer that is transmitted only in the first cell without being subject to bearer splitting,
Resource allocation method. The determination is
Receiving uplink grants from both the first and second cells;
The second logical channel including the first logical channel to generate a second Medium Access Control Protocol Data Unit (MAC PDU) transmitted in the second cell in accordance with an uplink grant in the second cell; Allocating uplink resources of the second cell to at least one logical channel transmitted in the first cell and transmitting in the first cell according to uplink grant in the first cell In order to generate one MAC PDU, the plurality of logical channels transmitted in the first cell in consideration of the uplink resource amount of the second cell allocated to the first logical channel Allocating uplink resources of the first cell to
The resource allocation method according to claim 1, comprising: The determination is that as the uplink resource amount of the second cell that can be allocated to the first logical channel is larger, the uplink resource amount of the first cell that is allocated to the first logical channel. The resource allocation method according to claim 1, comprising reducing The determination is
Trying to reserve the prioritized bit rate (PBR) of the first logical channel in preference to the uplink resource of the second cell rather than the uplink resource of the first cell; and Among the PBR of one logical channel or the reference resource amount calculated based on the PBR, the shortage that cannot be secured from the uplink resource of the second cell is determined from the uplink resource of the first cell. To secure,
The resource allocation method according to any one of claims 1 to 3, further comprising: The determination is
Trying to allocate uplink resources of the first cell to the plurality of logical channels including the first and second logical channels according to a Logical Channel Prioritization (LCP) procedure; and after the trial When transmission data remains in a transmission buffer corresponding to the second logical channel, the resource amount allocated to the first logical channel in the trial is reduced by a first amount, and the first amount is reduced to the first amount. Redistribute to a second logical channel;
The resource allocation method according to claim 1 or 2, comprising: The redistribution means that the uplink resource amount of the second cell allocated to the first logical channel is equal to the uplink of the first cell allocated to the first logical channel in the trial. 6. The resource allocation method according to claim 5, comprising redistributing the first amount to the second logical channel on condition that the amount exceeds a predetermined amount than a link resource amount. The reallocation is performed on the condition that the uplink resource amount of the second cell allocated to the first logical channel is equal to or higher than Prioritized Bit Rate (PBR) of the first logical channel. 6. The resource allocation method according to claim 5, comprising redistributing the first amount to the second logical channel. The resource allocation method according to any one of claims 5 to 7, wherein the second logical channel is given higher priority than the first logical channel. The resource allocation method according to any one of claims 1 to 8, wherein the first base station is a main base station and the second base station is a sub-base station. A wireless terminal,
Control means for controlling dual connectivity with bearer division in which a first network bearer between the wireless terminal and the core network is divided into first and second base stations;
Transmission data processing means;
With
The transmission data processing means takes into account the amount of uplink resources that can be allocated to the first logical channel of the first network bearer in the second cell managed by the second base station, and Configured to determine an assignment of uplink resources of a first cell managed by a first base station to a plurality of logical channels;
The plurality of logical channels include the first logical channel and a second logical channel of a second network bearer that is transmitted only in the first cell without being subject to bearer splitting,
Wireless terminal. The transmission data processing means includes
Configured to receive an uplink grant from both the first and second cells;
Including the first logical channel to generate a second Medium Access Control Protocol Data Unit (MAC PDU) to be transmitted on the uplink of the second cell according to the uplink grant in the second cell The first cell is configured to allocate uplink resources of the second cell to at least one logical channel transmitted in the second cell, and according to an uplink grant in the first cell In order to generate the first MAC PDU transmitted in the uplink of the first cell, the uplink resource amount of the second cell allocated to the first logical channel is taken into account in the first cell. Configured to allocate uplink resources of the first cell to the plurality of logical channels to be transmitted;
The wireless terminal according to claim 10. When the transmission data processing means allocates the uplink resource of the first cell, the larger the uplink resource amount of the second cell that can be allocated to the first logical channel is, The radio terminal according to claim 10 or 11, wherein an uplink resource amount of the first cell assigned to a logical channel is reduced. The transmission data processing means includes
When allocating the uplink resource of the first cell, the prioritized bit rate (PBR) of the first logical channel is set to the uplink of the second cell rather than the uplink resource of the first cell.・ Attempts to secure priority over resources,
Of the PBR of the first logical channel or the reference resource amount calculated based on the PBR, the shortage that cannot be secured from the uplink resource of the second cell Secure from resources,
The wireless terminal according to any one of claims 10 to 12. The transmission data processing means includes
When allocating uplink resources of the first cell, uplink of the first cell with respect to the plurality of logical channels including the first and second logical channels according to a Logical Channel Prioritization (LCP) procedure Attempt to allocate link resources,
If transmission data remains in the transmission buffer corresponding to the second logical channel after the trial, the amount of resources allocated to the first logical channel in the trial is reduced by a first amount, and the first Redistribute the amount of the second logical channel to the second logical channel;
The wireless terminal according to claim 10 or 11. The transmission data processing means is configured so that an uplink resource amount of the second cell assigned to the first logical channel is equal to an uplink amount of the first cell assigned to the first logical channel in the trial. The wireless terminal according to claim 14, wherein the first amount is redistributed to the second logical channel on condition that the amount exceeds a predetermined amount than a link resource amount. The transmission data processing means is provided on the condition that the uplink resource amount of the second cell allocated to the first logical channel is equal to or higher than Prioritized Bit Rate (PBR) of the first logical channel. The wireless terminal according to claim 14, wherein the first amount is redistributed to the second logical channel. The wireless terminal according to any one of claims 14 to 16, wherein the second logical channel is given higher priority than the first logical channel. The wireless terminal according to any one of claims 10 to 17, wherein the first base station is a main base station and the second base station is a sub base station. A non-transitory computer-readable medium storing a program for causing a computer to perform the method according to any one of claims 1 to 9. A first base station managing a first cell;
A second base station managing a second cell;
A wireless terminal supporting dual connectivity with bearer division in which a first network bearer between a wireless terminal and a core network is divided into the first base station and the second base station;
With
The wireless terminal considers the amount of uplink resources that can be allocated to the first logical channel of the first network bearer in the second cell, and then sets a plurality of uplink resources of the first cell. Configured to determine the allocation for a logical channel of
The plurality of logical channels include the first logical channel and a second logical channel of a second network bearer that is transmitted only in the first cell without being subject to bearer splitting,
Wireless communication system.

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