阅读说明：本技术 用户装置、以及上行发送定时控制方法 (User equipment and uplink transmission timing control method ) 是由 内野彻 高桥秀明 W.A.哈普萨里 武田一树 于 2015-07-29 设计创作，主要内容包括：用户装置包括：信号发送单元,发送上行信号；信号接收单元,接收下行信号；以及定时调整单元,进行如下的定时控制,即以下行信号的接收定时作为基准,将上行信号的发送定时向前偏移,在所述载波聚合中使用的小区中由使用同一个上行发送定时的副小区组成的小区组内,存在设定物理上行控制信道的副小区的情况下,所述定时调整单元使用与该副小区的帧结构相应的偏移值,进行针对所述小区组的所述定时控制。(The user device includes: a signal transmitting unit which transmits an uplink signal; a signal receiving unit which receives a downlink signal; and a timing adjustment unit configured to perform timing control for shifting a transmission timing of an uplink signal forward with reference to a reception timing of the downlink signal, wherein when a secondary cell for setting a physical uplink control channel is present in a cell group including secondary cells using the same uplink transmission timing among cells used for the carrier aggregation, the timing adjustment unit performs the timing control for the cell group using an offset value corresponding to a frame structure of the secondary cell.)

1. A user device, comprising:

a signal transmitting unit that transmits an uplink signal to a communication device;

a signal receiving unit that receives a downlink signal from the communication device; and

a timing adjustment unit configured to perform timing control to shift a transmission timing of an uplink signal transmitted from the signal transmission unit to the communication device with reference to a reception timing of a downlink signal received from the communication device by the signal reception unit,

the timing adjustment unit performs the timing control for a plurality of cells using the same offset value for the plurality of cells regardless of a difference in frame structure among the plurality of cells constituting a timing advance group.

2. An uplink transmission timing control method executed by a user equipment, the uplink transmission timing control method comprising:

a signal transmission step of transmitting an uplink signal to a communication device;

a signal reception step of receiving a downlink signal from the communication device; and

a timing adjustment step of performing timing control to shift a transmission timing of the uplink signal to the communication apparatus in the signal transmission step with reference to a reception timing of the downlink signal from the communication apparatus in the signal reception step,

in the timing adjustment step, the timing control for the plurality of cells is performed using the same offset value for the plurality of cells regardless of a difference in frame structure among the plurality of cells constituting a timing advance group.

Technical Field

The present invention relates to a mobile communication system, and more particularly, to uplink transmission timing control in carrier aggregation.

Background

In LTE-Advanced, in order to achieve throughput exceeding LTE while ensuring backward compatibility with LTE, Carrier Aggregation (CA) is employed in which communication is performed using a plurality of carriers at the same time with a bandwidth (maximum 20MHz) supported in LTE as a basic unit (see, for example, non-patent document 1). A Carrier that becomes a basic unit in Carrier aggregation is called a Component Carrier (CC).

In CA, a PCell (primary cell) with high reliability for ensuring connectivity and an SCell (Secondary cell) as an additional cell are set in the user equipment UE. The user equipment UE is first connected to the PCell and can add an SCell as needed. The PCell is the same cell as a cell in the LTE scheme supporting RLM (Radio link monitoring) and SPS (Semi-Persistent Scheduling).

The SCell is a cell that is added to the PCell and set in the user equipment UE. The SCell addition, setting change, and deletion are performed by RRC (Radio Resource Control) signaling. The SCell is a cell that can communicate (can be scheduled) after being activated in a MAC (media access Control) layer because it is in a deactivated state (deactivated state) immediately after being set to the user equipment UE. The SCell is controlled activated (activation)/deactivated (deactivation) by a MAC signal from the base station eNB.

CA prior to Rel-11 is assumed to perform simultaneous communication using a plurality of CCs under the same base station eNB, but Rel-12 is further expanded to propose Dual connectivity (Dual connectivity) that performs simultaneous communication using CCs under different base station enbs and achieves high throughput (non-patent document 2). That is, in dual connectivity (dual connectivity), the user equipment UE communicates using radio resources of two physically different base stations eNB at the same time.

Dual connectivity (hereinafter, DC) is one type of CA, also called inter-eNB CA (inter-eNB CA) (inter-base-station carrier aggregation), and a Master eNB (Master-eNB (menb)) and a slave eNB (Secondary-eNB (senb)) are introduced.

In DC, the Cell(s) under the MeNB is/are referred to as MCG (Master Cell Group), and the Cell(s) under the SeNB is/are referred to as SCG (Secondary Cell Group). The CC of UL is set in at least one SCell in the SCG, and PUCCH is set in one of them. This SCell is referred to as PSCell (primary SCell). Further, it may also be referred to as a special cell (special cell).

In the LTE system using SC-FDMA for uplink transmission, uplink signals from different user apparatuses UE in a cell received by a base station eNB are collectively demodulated by FFT. However, since the signal propagation delays (radio characteristics) of the user apparatuses UE are different from each other, if each user apparatus UE in a cell transmits an uplink signal in accordance with the reception timing of a downlink signal from the base station eNB, the uplink signal of each user apparatus UE is received at different timing in the base station eNB, and the base station eNB cannot perform FFT at desired timing. Therefore, the base station eNB adjusts the transmission timing of the uplink signal of each user apparatus UE, and controls the reception timing in the base station eNB to be shifted within a predetermined time. This is called TA (Time alignment) control. Specifically, the base station eNB measures a difference between the actual uplink signal reception timing and the desired uplink signal reception timing for each user equipment UE, and instructs the user equipment UE to shift the uplink signal timing forward by the difference. In addition, the uplink transmission timing adjustment instruction from the base station eNB can be notified by a random access procedure or a MAC control signal.

As one example of CA, there is a method of operating CA between macro cells and small cells of different frequencies, as illustrated in fig. 1. In the system shown in fig. 1, the base station eNB forms a PCell and an SCell1 as macro cells, and further forms an SCell2 and an SCell3 as small cells from an RRE (Remote Radio Equipment) extending from the base station eNB, so that the user Equipment UE implements CA.

In such a configuration, the user equipment UE has different radio characteristics such as propagation delay between the aggregated CCs, and in uplink transmission timing control in UE units, a deviation in reception timing occurs in the base station eNB, which causes intra-cell interference, and therefore, it is necessary to perform uplink transmission timing control for each of the aggregated CCs.

Specifically, in Rel-11, CCs (cells) set in the user equipment UE are grouped into CCs having almost the same radio characteristics, and uplink transmission Timing adjustment control is performed for each CC (cell) Group (Timing Advanced Group). That is, the TAG is a group of cells using the same uplink transmission timing. The "same uplink transmission timing" is not necessarily strictly the same, and may be regarded as the "same uplink transmission timing" as long as the uplink transmission timing difference between cells is within a predetermined range. TAGs are largely divided into pTAG (primary TAG) containing the PCell in CA, and sstag (secondary TAG) consisting of no PCell but only scells. In the configuration of fig. 1, for example, as shown in fig. 2, pTAG consisting of PCell and SCell1, and setag consisting of SCell2 and SCell3 are set for the user equipment UE.

In the TAG, a timing reference cell (timing reference cell) is defined as a DL cell to be referred to when adjusting the timing of the DL or a clock (clock) in the device (for example, non-patent document 1). As shown in fig. 3A, B, each cell in the pTAG is specified to refer to the PCell as a timing reference cell (timing reference cell), and the timing reference cell (timing reference cell) is autonomously selected by the user equipment UE with respect to each SCell in the setg.

Disclosure of Invention

Problems to be solved by the invention

In LTE, two Duplex systems (Duplex mode) are specified, namely, a Frequency Division Duplex (FDD) system and a Time Division Duplex (TDD) system. In the FDD scheme, uplink communication and downlink communication are performed in different frequency bands, and in the TDD scheme, uplink communication and downlink communication are separated in time by using the same frequency band.

Regarding CA and duplex mode (duplex mode), in rel.10-11 of LTE, a plurality of CCs constituting CA are limited to the same duplex mode (duplex mode), CA is extended in Rel-12, and CA can be performed using CCs of different duplex modes (duplex mode). Hereinafter, CA of a CC using a different duplex mode (duplex mode) is referred to as TDD-FDD CA.

In conventional TDD-FDD CA, when an SCell having a frame structure (duplex mode) different from that of another cell is included in the tag, it is specified that the UL transmission timing is always advanced by NTAoffset (624 Ts) (non-patent document 3). As described in non-patent document 4, a carrier having a frame structure type 1(frame structure type 1) corresponds to a carrier for FDD, and a carrier having a frame structure type 2(frame structure type 2) corresponds to a carrier for TDD. Fig. 4A is a diagram illustrating a TA in the case where an SCell with a different frame structure (duplex mode) is not included in the tag, for example, an SCell of FDD only. As shown in fig. 4A, in this tag, a time earlier by TA than the DL signal reception timing is set as the UL signal transmission timing. Fig. 4B is a case where an SCell with a different frame structure (duplex mode) is contained within the tag. In this case, in this tag, a time earlier than the DL reception timing by TA +624Ts is set as the UL signal transmission timing. Further, UL transmission timing to which NTAoffset is applied is described in 8.1Uplink-downlink frame timing of non-patent document 4.

The reason for performing the above control is that NTAoffset to be applied differs depending on the duplex mode (0 in the case of FDD and 624Ts in the case of TDD), and it is necessary to align the ntag to a certain position within the same tag. In addition, Ts is a predetermined time. Further, 624Ts are added in case of TDD because time for switching UL reception and DL transmission in the base station eNB is considered.

However, in the above-described conventional art, activation/deactivation of an SCell (activation) or presence/absence of setting of a UL CC in the tag is not considered. Thus, for example, it is envisaged that in case the TDD scells within the setag are all deactivated, or in case the UL CC is deleted, the user equipment UE will autonomously stop the advance of the TA. Since such control depends on the installation of the user equipment UE, it is also considered that such control is not performed in another user equipment UE. Since the base station eNB cannot expect such control, it is considered that UL transmission timing is shifted and UL interference occurs when the control is performed. That is, in the conventional art, in the transmission timing control of the uplink signal of the user equipment UE, since the offset value cannot be appropriately applied, there is a problem that UL interference may occur.

The DC is one of CA, and PCell and SCell are set, and pTAG and tags are set. Therefore, it is considered that the user equipment UE performs control to always advance the UL transmission timing by the NTAoffset 624Ts when the sctag includes an SCell having a frame structure (duplex mode) different from that of the other scells according to the above-described rule, but there is a problem similar to the above because activation/deactivation (deactivation) of the SCell in the sctag or the presence or absence of the UL cc setting is not considered as described above.

To eliminate the above problem, for example, it is considered to determine conditions for applying an activation state of NTAoffset 624Ts or ULCC setting, and the like. However, in DC, since it is negotiated to set the PSCell in the tags as a DL timing reference cell (DL timing reference cell), it is also considered that the user equipment UE applies NTAoffset conforming to the duplex mode of the PSCell if this is assumed. That is, in this case, the user equipment UE applies NTAoffset 624Ts in TA control if the PSCell is TDD and 0 if the PSCell is FDD, among the tags including the PSCell.

TDD-FDD CA is always used in a group with only DC, and although it is sufficient to determine the NTAoffset value based on the duplex mode of the PSCell, it would lead to an increase in complexity of device installation if it is determined intentionally whether or not an SCell having a different frame structure is set to the sctag including the PSCell and the NTAoffset value is determined. That is, even in DC, there is a problem that the offset value cannot be appropriately applied in the transmission timing control of the uplink signal of the user equipment UE.

The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a technique capable of appropriately applying an offset value to control transmission timing of an uplink signal of a user equipment having a function of communicating with another communication apparatus by carrier aggregation using a carrier having a specific frame structure and a carrier having a frame structure different from the specific frame structure.

Means for solving the problems

According to an embodiment of the present invention, there is provided a user apparatus including:

a signal transmitting unit that transmits an uplink signal to a communication device;

a signal receiving unit that receives a downlink signal from the communication device; and

a timing adjustment unit configured to perform timing control to shift a transmission timing of an uplink signal transmitted from the signal transmission unit to the communication device with reference to a reception timing of a downlink signal received from the communication device by the signal reception unit,

the timing adjustment unit performs the timing control for a plurality of cells using the same offset value for the plurality of cells regardless of a difference in frame structure among the plurality of cells constituting a timing advance group.

Further, according to an embodiment of the present invention, an uplink transmission timing control method performed by a user equipment includes:

a signal transmission step of transmitting an uplink signal to a communication device;

a signal reception step of receiving a downlink signal from the communication device; and

a timing adjustment step of performing timing control to shift a transmission timing of the uplink signal to the communication apparatus in the signal transmission step with reference to a reception timing of the downlink signal from the communication apparatus in the signal reception step,

in the timing adjustment step, the timing control for the plurality of cells is performed using the same offset value for the plurality of cells regardless of a difference in frame structure among the plurality of cells constituting a timing advance group.

According to an embodiment of the present invention, there is provided a user equipment having a function of communicating with another communication apparatus by carrier aggregation using a carrier having a specific frame structure and a carrier having a frame structure different from the specific frame structure, the user equipment including:

a signal transmission unit configured to transmit an uplink signal to the communication device;

a signal receiving unit that receives a downlink signal from the communication device; and

a timing adjustment unit configured to perform timing control for shifting forward a transmission timing of an uplink signal to the communication device, the transmission timing being transmitted from the signal transmission unit, with reference to a reception timing of the downlink signal from the communication device received by the signal reception unit,

in the case where there is a secondary cell in which a physical uplink control channel is set in a cell group consisting of secondary cells using the same uplink transmission timing among cells used for the carrier aggregation, the timing adjusting section performs the timing control for the cell group using an offset value corresponding to a frame structure of the secondary cell.

Further, according to an embodiment of the present invention, there is provided an uplink transmission timing control method performed by a user equipment having a function of communicating with another communication apparatus by carrier aggregation using a carrier having a specific frame structure and a carrier having a frame structure different from the specific frame structure, the uplink transmission timing control method including:

a timing adjustment step of performing timing control for shifting forward a transmission timing of an uplink signal to the communication apparatus with reference to a reception timing of a downlink signal from the communication apparatus,

in the timing adjustment step, when a secondary cell for setting a physical uplink control channel is present in a cell group consisting of secondary cells using the same uplink transmission timing among the cells used for the carrier aggregation, the user equipment performs the timing control for the cell group using an offset value corresponding to a frame structure of the secondary cell.

Effects of the invention

According to an embodiment of the present invention, an offset value can be appropriately applied to control of transmission timing of an uplink signal of a user equipment having a function of communicating with another communication apparatus by carrier aggregation using a carrier having a specific frame structure and a carrier having a frame structure different from the specific frame structure.

Drawings

Fig. 1 is a diagram for explaining an MTA.

Fig. 2 is a diagram for explaining TAG.

Fig. 3A is a diagram for explaining a timing reference cell (timing reference cell).

Fig. 3B is a diagram for explaining a timing reference cell (timing reference cell).

Fig. 4A is a diagram for explaining the problem.

Fig. 4B is a diagram for explaining the problem.

Fig. 5 is a configuration diagram of a communication system in the embodiment of the present invention.

Fig. 6A is a diagram illustrating an application example of NTAoffset.

Fig. 6B is a diagram for explaining an application example of NTAoffset.

Fig. 7A is a diagram for explaining condition example 2 in which NTAoffset 624Ts is applied.

Fig. 7B is a diagram for explaining condition example 2 in which NTAoffset 624Ts is applied.

Fig. 8A is a diagram for explaining condition example 3 in which NTAoffset 624Ts is applied.

Fig. 8B is a diagram for explaining condition example 3 in which NTAoffset 624Ts is applied.

Fig. 9A is a diagram for explaining condition example 4 in which NTAoffset 624Ts is applied.

Fig. 9B is a diagram for explaining condition example 4 in which NTAoffset 624Ts is applied.

Fig. 10 is a diagram showing an example of a case where NTAoffset 624Ts is being applied.

Fig. 11 is a configuration diagram of a communication system in modification 1.

Fig. 12A is a diagram for explaining an application example of NTAoffset in modification 1.

Fig. 12B is a diagram for explaining an application example of NTAoffset in modification 1.

Fig. 13A is a configuration diagram of a communication system in modification 2.

Fig. 13B is a configuration diagram of a communication system in modification 2.

Fig. 14 is a configuration diagram of a user equipment UE according to an embodiment of the present invention.

Fig. 15 is a diagram showing an example of the operation of the user equipment UE.

Fig. 16 is a diagram showing an example of the operation of the user equipment UE.

Fig. 17 is a diagram showing an example of the operation of the user equipment UE.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings. The embodiments described below are merely examples, and the embodiments to which the present invention is applied are not limited to the embodiments described below. In the present embodiment, the mobile communication system of LTE is used as the target, but the present invention is not limited to LTE and can be applied to other mobile communication systems. In the present specification and claims, unless otherwise specified, the term "LTE" is used in the meaning of Rel-12 or Rel-12 and beyond of 3 GPP.

(overview of embodiment and overall System configuration)

In the present embodiment, when performing TDD-FDD CA in DC, the user equipment UE applies NTAoffset corresponding to the duplex mode of the PSCell to the tag including the PSCell. The following control is performed for the tags that do not include PSCell. TDD-FDD CA in DC is an example of carrier aggregation using a carrier of the time division duplex scheme and a carrier of the frequency division duplex scheme.

Fig. 5 shows an example of a configuration of a communication system according to an embodiment of the present invention. As shown in fig. 5, the communication system according to the present embodiment includes a base station MeNB and a base station SeNB connected to a core network, respectively, and is capable of performing Dual Connectivity (DC) with a user equipment UE. The base station MeNB and the base station SeNB can communicate with each other via an X2 interface, for example.

In the communication system shown in fig. 5, for example, the PCell and the SCell (including the PSCell) can be set in the same manner as in the system shown in fig. 1, with the MCG being a macro cell and the SCG being a small cell. It is assumed that addition, deletion, and setting change of the SCell (including the PSCell) in the user equipment UE are performed by RRC signaling from the base station MeNB, but the present invention is not limited thereto. Further, it is assumed that the setting of the MTA (that is, the setting of the tag and the pTAG) in the user equipment UE is also performed by RRC signaling from the base station MeNB, but is not limited thereto.

Further, activation/deactivation of scells may be performed by the base station SeNB for SCG and the base station MeNB for MCG, or may be performed by the base station MeNB for all scells.

The user equipment UE recognizes the TA for the TAG from the MAC signal received from the MeNB or SeNB, and adjusts the UL transmission timing for each TAG using the TA and NTAoffset. In the present embodiment, attention is particularly paid to control for determining NTAoffset.

(example in the case where PSCell is contained in sTAG)

An application example of NTAoffset in the case where PSCell is included in tags will be described with reference to fig. 6A and 6B. As the structure of this tags in the case where PSCell is contained in tags, there are the following cases: a case where the sstag other than the PSCell is composed of only scells of scg (senb), a case where the sstag other than the PSCell is composed of only scells of mcg (menb), a case where the sstag other than the PSCell is composed of scells of scg (senb) and mcg (menb), and the like.

Fig. 6A shows a case where pscell (FDD), SCell1(TDD), and SCell2(FDD) are set to setag in the user apparatus UE. In this case, since the PSCell is FDD, NTAoffset of FDD is applied to this tag. That is, NTAoffset is applied to 0.

Fig. 6B shows a case where pscell (TDD), SCell1(TDD), and SCell2(FDD) are set to setag in the user apparatus UE. In this case, since the PSCell is TDD, NTAoffset of TDD is applied in this tag. That is, NTAoffset 624Ts is applied.

(example of case where PSCell is not contained in sTAG)

The above example is an example in the case where the sctag contains PSCell, but in some DC, the sctag does not contain PSCell. For example, there are cases where: a case where the sctag is constituted by an SCell in the MCG, a case where the sctag is constituted by an SCell other than the PSCell in the SCG, a case where the sctag is constituted by an SCell in the MCG and an SCell in the SCG (including no PSCell), or the like. In this case, as described above, the conventional technique does not consider the problem that UL interference may occur due to activation (activation)/deactivation (deactivation) of the SCell in the sctag or the presence or absence of setting of the UL CC, and therefore the control described below is performed in the present embodiment. The control described below is also applicable to CA other than DC as shown in fig. 1. The "base station eNB" in the following DC forms the SCell included in the setag, and is the MeNB or SeNB that receives the uplink signal from the user equipment UE.

In the present embodiment, when a cell having a different frame structure (duplex mode) is set in the same tag (that is, when FDD and TDD coexist in the SCell constituting the tag), the user equipment UE applies NTAoffset 624Ts under the following conditions (conditional example 1 to conditional example 4), and the base station eNB performs a reception operation or generation/transmission of a TA command assuming that the base station eNB applies NTAoffset 624Ts under the conditions and performs UL transmission.

< Condition example 1>

Conditional example 1 is an example in which 624Ts are applied regardless of whether or not UL CC and activation/deactivation states are set for each SCell when a different duplex mode cell is set in the same tag. For example, when the SCell1(TDD), the SCell2(FDD), or the SCell3(FDD) is set as the setag in the user equipment UE, the user equipment UE applies NTAoffset ═ Ts 624 to UL transmission timing control in the SCell included in the SCell1 to 3, regardless of whether or not the UL CC is set in the SCell1 to 3 or the activation/deactivation state.

< Condition example 2>

Conditional example 2 is that, in the user equipment UE, an SCell of Frame structure 2(Frame structure2) (TDD) exists within the same setag, and if at least one SCell in the SCell of TDD is in an active state, then NTAoffset is applied as 624 Ts. In conditional example 2, the presence or absence of UL CC in the SCell of the active TDD is not a condition. That is, even when only DL CCs are set and UL CCs are not set in scells of the active TDD, the condition example 2 is applied.

An application example of the condition example 2 will be described with reference to fig. 7A and 7B. Fig. 7A shows that SCell1(TDD), SCell2(FDD), SCell3(FDD) are set to setag and SCell1 is in an active state in user equipment UE. In this case, since the condition of applying 624Ts is satisfied, NTAoffset 624Ts is applied to this setag.

In fig. 7B, SCell1(TDD), SCell2(FDD), SCell3(FDD) are set to setag in the user equipment UE, but SCell1 is in a deactivated state. In this case, since the condition for applying 624Ts is not satisfied, NTAoffset ═ 0 is applied to this tag.

< Condition example 3>

Conditional example 3 is such that when an SCell of Frame structure 2(TDD) exists in the same setag in the user equipment UE and UL CC (UL communication) is set in at least one SCell in the SCell in TDD, NTAoffset 624Ts are applied. Further, setting of UL CC for SCell is performed by RRC signaling, for example. DL is necessarily set when setting SCell.

In conditional example 3, the activation/deactivation state in the SCell in TDD in which the UL CC is set is not a condition. That is, even if the SCell of the TDD in which the UL CC is set is in the deactivated state, condition example 3 is applied.

An application example in the condition example 3 is explained with reference to fig. 8A and 8B. Fig. 8A shows that SCell1(TDD), SCell2(TDD), SCell3(FDD) are set to setag, and that SCell1 is set to DL and UL in the user equipment UE. In this case, since the condition of applying 624Ts is satisfied, NTAoffset 624Ts is applied to this setag.

Fig. 8B shows that SCell1(TDD), SCell2(TDD), and SCell3(FDD) are set to tags in the user equipment UE, but only DL CCs are set and UL CCs are not set in scells in TDD. In this case, since the condition for applying 624Ts is not satisfied, NTAoffset ═ 0 is applied to this tag.

< Condition example 4>

Conditional example 4 is such that, in the user equipment UE, if an SCell of Frame structure 2(Frame structure2) (TDD) exists within the same setag, and UL CC (UL communication) is set in at least one of the scells of the TDD, and the SCell is in an active state, then NTAoffset is applied as 624 Ts. In addition, activation/deactivation is performed per SCell. For example, when an SCell with UL and DL set is activated, both UL and DL are activated and communication is enabled.

An application example in the condition example 4 is explained with reference to fig. 9A and 9B. Fig. 9A shows that SCell1(TDD), SCell2(TDD), SCell3(FDD) are set to setag, and the SCell of TDD is set to DL, UL and is in an active state in the user equipment UE. In this case, since the condition of applying 624Ts is satisfied, NTAoffset 624Ts is applied to this setag.

Fig. 9B shows that SCell1(TDD), SCell2(TDD), SCell3(FDD) are set to setag, and the SCell of TDD is set to DL, UL but in a deactivated state in the user equipment UE. In this case, since the condition for applying 624Ts is not satisfied, NTAoffset ═ 0 is applied to this tag.

In the present embodiment, the base station eNB (MeNB or SeNB) grasps the same conditions as those on the user equipment UE side as described above, and the base station eNB grasps whether NTAoffset 624Ts is to be applied for each tag of each user equipment UE, based on the setting state of the SCell of each user equipment UE managed thereby, or the like. Thus, the base station eNB can normally demodulate the received UL signal while avoiding UL interference.

In addition to the base station eNB grasping whether or not to apply NTAoffset 624Ts using the same conditions as the user equipment UE as described above, the base station eNB may explicitly notify the base station eNB of the application of NTAoffset 624Ts from the user equipment UE. This notification may also apply in case the PSCell is contained in the tags.

For example, as shown in fig. 10, when the above condition is satisfied and NTAoffset 624Ts starts to be applied to this setag (step 101), the user equipment UE notifies the base station eNB of the start of application of 624Ts (step 102). The notification includes, for example, an ID of the tag, information indicating that 624Ts is applied, and the like.

In the example of fig. 10, if the condition for applying NTAoffset 624Ts is not satisfied in step 103 and application of 624Ts is stopped, the user apparatus UE notifies the base station eNB that 624Ts is stopped (step 104). The notification includes, for example, an ID of the tag, information indicating that the application 624Ts is stopped, and the like.

The trigger of the notification may be application start/application stop at 624Ts as described above, or may be an application condition/unsatisfied condition that satisfies 624 Ts.

Further, the signal for notification may be any one of an RRC signal, a MAC signal, and a signal of PHY. In the notification, in order To suppress frequent reporting when the condition is satisfied or dynamically changed, it is also possible To add a TTT (Time To Trigger) or a protection level.

< other examples >

In the above example, the user equipment UE and the base station eNB determine application/non-application of NTAoffset 624Ts based on a predetermined condition, or the user equipment UE determines application/non-application of NTAoffset 624Ts based on a predetermined condition and notifies the base station eNB of the application/non-application of 624 Ts.

For example, the base station eNB performs UL signal reception control as it always does not apply NTAoffset to 624Ts in the tag, and when the aforementioned 624Ts application condition is satisfied, the user apparatus UE stops all UL transmissions in the corresponding tag.

For example, the base station eNB may perform UL signal reception control as to always apply NTAoffset 624Ts to the setag, and when the aforementioned 624Ts application condition is not satisfied, the user apparatus UE may stop all UL transmissions in the corresponding setag.

Regarding the stopping of UL transmission, the user equipment UE may stop only UL transmission, may stop a TA timer (TA timer) managed for the tag (or may consider the TA timer to expire), may release individual resources (SRS resources) of the SCell, or may deactivate all scells in the tag.

In addition, whether or not to perform UL transmission stop control as described above may be notified from the base station eNB to the user equipment UE by RRC signaling, MAC signal, or the like. Alternatively, when the base station eNB notifies the user apparatus UE of the fact that the condition determination function of the application 624Ts is provided, the base station eNB may perform application control of the application 624Ts according to the application condition of the application 624Ts, and when the base station eNB does not notify the user apparatus UE of the fact that the condition determination function of the application 624Ts is provided, the base station eNB may perform the present UL transmission stop control.

(modification 1)

In the present embodiment, DC is basically assumed, but the method of controlling the PSCell duplex mode can be applied not only to DC. For example, it is considered that the function of the PSCell (for example, PUCCH transmission function) defined in DC is used for CA (for example, fig. 1) other than DC, and that NTAoffset control similar to DC can be performed when the function of the PSCell is used for CA.

Fig. 11 shows a configuration diagram of a communication system according to modification 1. This communication system is a communication system that performs CA other than DC. As shown in fig. 11, the communication system in modification 1 is a mobile communication system including a base station eNB and a user equipment UE. In fig. 11, one base station eNB and one user equipment UE are shown, but this is for convenience of illustration and a plurality of base stations eNB and user equipment UE may be present.

In the example of fig. 11, the base station eNB itself has a radio unit, and a radio unit (RRE: remote radio apparatus) is also provided at a place distant from the base station eNB. The radio unit is part of the base station eNB, for example connected to the base station eNB by an optical fiber. In modification 1, CA can be performed by the PCell and the SCell, as in the case of the embodiment shown in fig. 1.

In this communication system, for example, the base station eNB transmits an RRC message to the user equipment UE to add one or more scells constituting the small cell, based on the measurement result of the small cell CC received from the user equipment UE connected to the macro cell. Further, the base station eNB transmits a signal to activate the SCell to the user equipment UE. In this way, the user equipment UE performs CA with the small cell and the macro cell.

The user apparatus UE receives the setting of MTA (that is, the setting of TAGs and ptags) in an RRC message received from the base station eNB, for example, and recognizes the TA for the TAGs from a MAC signal, and adjusts the UL transmission timing for each TAG using the TA and NTAoffset.

In the system configuration shown in fig. 11, PUCCH (physical uplink control channel) resources are allocated to one SCell among scells in a small cell that communicates with an RRE, and the SCell is managed as a special SCell that is distinguished from other scells, and the value of NTAoffset is determined based on the duplex pattern for the tag including the SCell, as in the PSCell described above. Hereinafter, for convenience of explanation, such an SCell in CA other than DC is referred to as a special SCell. The control described above is applied to the tag that does not include the special SCell (the aforementioned condition examples 1 to 4 and the like).

In modification 1, as described with reference to fig. 10, the base station eNB may be notified of the application/non-application of NTAoffset 624 Ts.

An application example of modification 1 in which the special SCell is applied will be described with reference to fig. 12A and 12B. Fig. 12A shows that SCell1(FDD, PUCCH), SCell2(TDD), and SCell3(FDD) are set to setag in the user equipment UE. In this case, since SCell1 is a special SCell, NTAoffset of FDD, which is a duplex mode of the special SCell, is applied to this tag. That is, NTAoffset is applied to 0.

Fig. 12B shows that, in the user equipment UE, SCell1(FDD), SCell2(TDD), and SCell3(FDD) are set to setag. No special SCell is set. Where SCell2 is TDD, UL is set, and is in active state. Therefore, the aforementioned condition is satisfied, and NTAoffset is applied as 624 Ts.

(modification 2)

In mobile communications, it is common to perform communication between user apparatuses UE by performing communication (cellular communication) between the user apparatuses UE and a base station eNB, but in recent years, various techniques for D2D communication in which communication is directly performed between the user apparatuses UE using an interface of LTE have been studied. In the D2D communication technology, the user equipment UE performs direct communication between the user equipment UE using radio resources (time/frequency resources) used in LTE communication. As the D2D communication, for example, there are the following communications: one user apparatus UE transmits (broadcasts) a Discovery (Discovery) signal including its own identification information, and receives the Discovery (Discovery) signal from the other user apparatus UE, thereby discovering Communication (Communication) between the user apparatuses UE of the other party of Communication, Communication (Communication) performed between the user apparatuses UE after the Discovery, and the like.

In D2D communication, communication on one carrier (CC) is currently assumed, but in the future, it is expanded, and D2D communication using a plurality of carriers appears. For example, as shown in fig. 13A, communication occurs in which D2D communication and communication between the base station eNB and the user equipment UE are performed simultaneously. Further, as shown in fig. 13B, communication using a plurality of carriers in D2D communication may occur.

In the communication system shown in fig. 13A, assuming that, for example, the base station eNB is regarded as the base station MeNB shown in fig. 5 (or eNB in fig. 11), the user apparatus UE2 is regarded as the base station SeNB shown in fig. 5 (or RRE in fig. 11), and the same communication as the CA communication in the communication system shown in fig. 5 (or fig. 11) is performed with the user apparatus UE1, the user apparatus UE1 can determine application/non-application of NTAoffset 624Ts and apply TA control when transmitting a signal to the other communication apparatus, as in the control described in the above embodiment (including modification 1).

In the system shown in fig. 13B, assuming that, for example, the user equipment UE2 is considered as a base station eNB performing CA, and CA communication is performed between the user equipment UE1 and a cell including a plurality of scells (which can form an sctag), the user equipment UE1 can determine an application/non-application of NTAoffset 624Ts and perform TA control, as in the control described in the above embodiment (including modification 1). In addition, 624Ts is used for NTAoffset of TDD in cellular communication, but 624Ts is not always necessary in D2D communication, and a separately defined offset value may be used.

(apparatus construction, operation example)

Fig. 14 is a functional block diagram of a user equipment UE according to an embodiment of the present invention (including modifications 1 and 20). As shown in fig. 14, the user equipment UE includes a DL signal reception unit 101, an UL signal transmission unit 102, a CA control unit 103, an SCell state storage unit 104, and an UL transmission timing adjustment unit 105. Fig. 14 shows only functional units of the user equipment UE particularly relevant to the present invention, and the user equipment UE also has at least a function not shown in the drawing for performing an operation conforming to LTE. Note that the configuration shown in fig. 14 is merely an example, and any name of function division or function unit may be used as long as the function is provided to enable the processing described in the present embodiment to be executed. Hereinafter, "base station eNB" is used in a broad sense including enbs that do not constitute DC, and menbs and senbs that constitute DC.

DL signal reception section 101 receives various downlink signals from base station eNB. UL signal transmission section 102 transmits various uplink signals to base station eNB. DL signal reception section 101 and UL signal transmission section 102 also have a function of performing communication by CA (including DC) using a plurality of CCs.

CA control section 103 performs control on CA in user equipment UE, such as management of PCell and SCell (including PSCell and special SCell) constituting CA (including storage of SCell state in SCell state storage section 104), addition/deletion of SCell based on an instruction from base station eNB, setting/change of UL/DL structure of SCell, and activation/deactivation.

The SCell status is stored in the SCell status storage unit 104. In particular, the SCell state storage unit 104 stores information (such as an ID) of an SCell belonging to the tag, a structure of the SCell (whether UL/DL setting is present or not, PSCell/special SCell, or the like), activation/deactivation states of the SCell, and the like, which are necessary for determining NTAoffset in TA control.

The UL transmission timing adjustment unit 105 performs TA control, i.e., UL transmission timing adjustment, based on the TA value received from the base station eNB and the NTAoffset value determined from the state stored in the SCell state storage unit 104. In addition, in a TAG, the DL signal reception timing that is a reference of the UL signal transmission timing of each cell can be, for example, the DL signal reception timing of a timing reference cell (timing reference cell) in the TAG. Further, UL transmission timing adjustment section 105 also includes a function of performing the aforementioned UL transmission stop control.

Next, an operation example of the user equipment UE will be described with reference to fig. 15 to 17. In the following operation example, it is assumed that the user equipment UE communicates with the base station eNB (MeNB or SeNB), but similar control can be performed even when communicating with another user equipment as described in modification 2.

In fig. 15, first, based on RRC signaling from the base station MeNB, the CA control unit 103 sets an SCell (including PSCell) in DC, sets MTA (tag, pTAG, or the like), and stores information about the set SCell in the SCell state storage unit 104 (step 201).

The UL transmission timing adjustment unit 105 refers to the SCell state storage unit 104, and determines whether or not there is a PSCell in the tags (step 202), and if there is a PSCell, the process proceeds to step 203, and if not, the process proceeds to step 204. In step 203, the UL tx timing adjustment unit 105 applies NTAoffset in compliance with the duplex mode of the PSCell to the tag to perform tx timing adjustment. In step 204, the process proceeds to step 301 in fig. 16 or step 401 in fig. 17, and determines whether NTAoffset 624Ts is to be applied or not by the determination process based on the aforementioned condition example. Fig. 16 corresponds to condition example 2, and fig. 17 corresponds to condition example 3. In addition, when NTAoffset is not applied to 624Ts, NTAoffset is applied to 0.

In step 301 in fig. 16, the UL transmission timing adjustment unit 105 refers to the SCell status storage unit 104, determines whether or not the SCell for TDD is present in the sctag, and proceeds to step 302 if present. In step 302, the UL transmission timing adjustment unit 105 refers to the SCell state storage unit 104, determines whether an SCell in an active state is present in the scells in TDD in the tag, and proceeds to step 303 if present. In step 303, the UL transmission timing adjustment unit 105 applies NTAoffset 624Ts to the tag to perform UL transmission timing adjustment.

In step 401 of fig. 17, the UL transmission timing adjustment unit 105 refers to the SCell status storage unit 104, determines whether or not an SCell for TDD is present in the sctag, and proceeds to step 402 if present. In step 402, the UL transmission timing adjustment unit 105 refers to the SCell state storage unit 104, determines whether or not an SCell with a UL CC set therein is present among the scells in TDD in the tag, and proceeds to step 403 if present. In step 403, the UL transmission timing adjustment unit 105 applies NTAoffset 624Ts to the tag to perform UL transmission timing adjustment.

In addition, the operation of conditional example 4 in which NTAoffset is 624Ts is applied can be performed by setting the condition of step 402 to "whether or not there is an SCell in which a UL CC is set and which is in an active state in the SCell in TDD".

As described above, according to an embodiment of the present invention, there is provided a user equipment having a function of communicating with another communication apparatus by carrier aggregation using a carrier having a specific frame structure and a carrier having a frame structure different from the specific frame structure, the user equipment including: a signal transmission unit configured to transmit an uplink signal to the communication device; a signal receiving unit that receives a downlink signal from the communication device; and a timing adjustment unit configured to perform timing control for shifting forward a transmission timing of an uplink signal to the communication apparatus, which is transmitted from the signal transmission unit, with reference to a reception timing of a downlink signal from the communication apparatus, which is received by the signal reception unit, and to perform the timing control for the cell group using an offset value corresponding to a frame structure of a secondary cell when the secondary cell in which a physical uplink control channel is set exists in the cell group including the secondary cells using the same uplink transmission timing among the cells used for the carrier aggregation.

According to the above configuration, in the transmission timing control of an uplink signal of a user equipment having a function of communicating with another communication apparatus by carrier aggregation using a carrier having a specific frame structure and a carrier having a frame structure different from the specific frame structure, an offset value can be appropriately applied.

The secondary cell for which the physical uplink control channel is set is, for example, a PSCell in a dual connection. With this configuration, the offset value can be determined based on the frame structure of the PSCell in the cell group, and thus the processing can be simplified.

For example, when there is no secondary cell in which a physical uplink control channel is set in the cell group, the timing adjustment unit determines whether or not a secondary cell using a carrier having the specific frame structure in the cell group satisfies a predetermined condition, and when the predetermined condition is satisfied, uses a predetermined offset value for the timing control for the cell group. According to this configuration, when there is no secondary cell in which a physical uplink control channel is set in the cell group, the offset value can be appropriately applied.

The predetermined condition is, for example, that a secondary cell using a carrier having the specific frame structure is in an active state. According to this configuration, since the predetermined offset value is applied when the active state is established, it is possible to suppress wasteful application of the offset value.

The predetermined condition may be that uplink communication is set in a sub-cell using a carrier having the specific frame structure. In this configuration, since the predetermined offset value is applied when the uplink communication is set, wasteful application of the offset value can be suppressed.

When the predetermined offset value is used for the timing control, the signal transmission unit may notify the communication device that the predetermined offset value is used. With this configuration, the communication device (e.g., base station) can recognize that a predetermined offset value is used, and can perform appropriate UL signal reception control.

In the timing control, when the predetermined offset value is not used, the signal transmission unit may notify the communication apparatus that the predetermined offset value is not used. With this configuration, the communication device (e.g., base station) can recognize that the predetermined offset value is not used, and can perform appropriate UL signal reception control.

The timing adjustment means may have the following functions: a function of stopping uplink signal transmission from the signal transmitting unit in the cell group when the secondary cell using the carrier having the specific frame structure satisfies the predetermined condition, or a function of stopping uplink signal transmission from the signal transmitting unit in the cell group when the secondary cell using the carrier having the specific frame structure does not satisfy the predetermined condition. By providing these functions, the counterpart communication device (e.g., base station) can appropriately perform the UL signal reception process even if it does not have a function of determining whether to apply or not apply a predetermined offset value to the cell group.

The communication device is, for example, a base station supporting dual connectivity or another user device performing D2D communication with the user device. This has the effect that the offset value can be appropriately applied not only to DC but also to D2D communication.

The functional configuration of the user equipment UE described in the present embodiment may be a configuration realized by the user equipment UE having a CPU and a memory executing a program by the CPU (processor), a configuration realized by hardware such as a hardware circuit including logic of the processing described in the present embodiment, or a configuration in which hardware of the program is mixed.

Similarly, the base station eNB (eNB, MeNB, SeNB) described in the present embodiment may be configured to be implemented by a CPU (processor) executing a program in the base station eNB including the CPU and a memory, may be configured to be implemented by hardware such as a hardware circuit including logic of the processing described in the present embodiment, or may be configured to have a mixture of hardware of the program.

While the embodiments of the present invention have been described above, the disclosed invention is not limited to such embodiments, and various modifications, alternatives, and substitutions will be apparent to those skilled in the art. Although specific numerical examples are used to facilitate understanding of the present invention, these numerical values are merely examples and any appropriate values may be used unless otherwise specified. The distinction of the items in the above description is not essential to the present invention, and items described in two or more items may be used in combination as necessary, and items described in one item may be applied to items described in another item (as long as there is no contradiction). The boundaries of functional units or processing units in a functional block diagram do not necessarily correspond to the boundaries of physical elements. Operations of a plurality of functional units may be performed by one physical element, or operations of one functional unit may be performed by a plurality of physical elements. For convenience of explanation, the user equipment UE has been explained using functional block diagrams, but such an apparatus may be realized by hardware, software, or a combination thereof. Software operated by a processor provided with the user equipment UE according to an embodiment of the present invention and software operated by a processor provided with the base station according to an embodiment of the present invention may be stored in a Random Access Memory (RAM), a flash memory, a Read Only Memory (ROM), an EPROM, an EEPROM, a register, a hard disk (HDD), a removable disk, a CD-ROM, a database, a server, and any other suitable storage medium, respectively.

The present invention is not limited to the above-described embodiments, and various modifications, alterations, substitutions, and the like are included in the present invention without departing from the spirit of the present invention.

This patent application is based on the priority claim of japanese patent application No. 2014-157065 applied on 31/7/2014, and the entire contents of japanese patent application No. 2014-157065 are incorporated into this application.

Description of the reference symbols

eNB, MeNB, SeNB base station

UE user equipment

101 DL signal receiving unit

102 UL signal transmitting unit

103 CA control unit

104 SCell state storage unit

105 UL transmission timing adjustment unit