HK1237174B - Deriving pcmax in dual connectivity - Google Patents

Description

Obtain PCMAX in dual connection

Technical Field

The present disclosure relates to wireless communication techniques, particularly in the context of dual connectivity.

Background Art

In dual connectivity (DC), a UE (which may also be referred to as a terminal) can be served by two or more network nodes, which may be referred to as a master/master eNB (MeNB) and a secondary eNB (SeNB), or primary and secondary, or anchor and booster, and each of which can be considered a "leg" providing dual connectivity. The UE can be configured with a PCC (primary component carrier) or primary cell (PCell) from both the MeNB and the SeNB. The PCells from the MeNB and SeNB are referred to as the PCell and PSCell (primary secondary cell), respectively. The PCell and PSCell typically operate the terminal or UE independently of each other. The terminal or UE may also be configured with one or more SCCs (secondary component carriers; secondary cells of carrier aggregation associated with a primary cell, such as a PCell or PSCell) from each of the MeNB and SeNB. The corresponding secondary serving cells served by the MeNB and SeNB may be referred to as SCells. For the associated primary cell group and secondary cell group, a terminal or UE in DC typically has separate TX/RX (transmitter/receiver) for each connection with the MeNB and SeNB, respectively. This allows the MeNB and SeNB to independently configure/control/schedule resources for the terminal or UE using one or more procedures (eg, Radio Link Monitoring (RLM), DRX cycle, etc.) on their respective PCells and PSCells.

As in the single connectivity state, the terminal may be subject to limitations (eg, regulatory and/or standard-defined limitations) regarding transmit power on the cell(s) or carrier(s) associated with each leg of the dual connectivity.

Summary of the Invention

The present disclosure aims to provide a solution for determining the transmission power of a terminal in dual connectivity.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are provided for illustrative purposes and are not intended to limit the scope of the illustrated embodiments.

Figure 1 shows a dual-connectivity deployment scenario;

FIG2 shows an example of the maximum reception timing difference in the synchronous and asynchronous modes of dual connectivity;

Figures 3(a)-(c) show different levels of subframe timing mismatch between subframes in MCG and SCG, respectively;

Figures 4(a) and (b) show examples of subframe pairing;

FIG5 shows an exemplary terminal;

FIG6 illustrates an exemplary network node;

FIG7 shows an example of a method for operating a terminal;

FIG8 shows an example of a terminal;

FIG9 shows an example of a method for operating a network node; and

FIG10 shows an example of a network node.

DETAILED DESCRIPTION

In the following, UE or user equipment may be used interchangeably for terminal; eNodeB may be used interchangeably for network node; and vice versa. The subclauses involved are related to the relevant 3GPP/LTE specifications.

FIG1 shows a dual-connectivity deployment scenario.

More specifically, Dual Connectivity (DC) is an operating mode of a terminal or UE, particularly in the RRC_CONNECTED state, in which the terminal or UE is configured with a Primary Cell Group (MCG) and a Secondary Cell Group (SCG). A Cell Group (CG) is a set of serving cells associated with a MeNB or SeNB. The MCG and SCG are defined as follows:

A Master Cell Group (MCG) is a group of serving cells associated with a MeNB, including a PCell and optionally one or more SCells.

A secondary cell group (SCG) is a group of serving cells associated with a SeNB, which includes a pSCell (primary Scell) and optionally one or more SCells.

Two modes of operation can be considered, the first being implemented in 3GPP EUTRA Rel. 12 and the other in subsequent releases of the standard:

Synchronous Operation: The downlink timing of the MeNB and SeNB is synchronized to approximately half of an OFDM symbol (approximately ±33 μs). This means that a terminal or UE supporting synchronous DC operation should be able to receive signals from both the MCG and SCG within ±33 μs. More specifically, in synchronous DC operation, the time difference (Δτ) between the signals received at the UE from the MeNB (i.e., from the serving cell in the MCG) and the SeNB (i.e., from the serving cell in the SCG) should be within a first limit (Γ1) or a first threshold (e.g., within ±33 μs).

Asynchronous operation: The downlink timing of the MeNB and SeNB is synchronized to half a subframe (±500μs). This means that a UE supporting asynchronous DC operation should have the ability to receive signals from the MCG and SCG within ±500μs. More specifically, in asynchronous DC operation, "Δτ" should be within a second limit (Γ2) or a second threshold (e.g., within ±500μs), where |Γ2|>|Γ1|. In some exemplary embodiments, if "Δτ" is outside the Γ1 range, the DC operation may be considered asynchronous. Furthermore, in some exemplary embodiments, if "Δτ" is allowed to have any arbitrary value, the DC operation may be considered asynchronous.

FIG2 shows the maximum reception timing difference in the synchronous mode and the asynchronous mode of dual connectivity.

The following discusses uplink power control. Uplink power control plays an important role in radio resource management, which is already adopted in most modern communication systems. It balances the need to maintain link quality with the need to minimize interference to other users of the system and maximize the battery life of the terminal.

In LTE, the purpose of power control is to determine the average power over the SC-FDMA symbol and it is applied to both common channels and dedicated channels (PUCCH/PUSCH/SRS). The combined open-loop power control and closed-loop power control can be defined as:

Open-loop power control: The terminal or UE calculates a basic open-loop setpoint based on the path loss estimate and an eNodeB-controlled semi-static base level (P ₀ ) consisting of a nominal power level common to all UEs or terminals in the cell and _a terminal or UE-specific offset;

Closed-loop power control: The network node or eNodeB updates the dynamic adjustment relative to a set point; the terminal or UE adjusts the transmit power based on commands such as TPC (Transmit Power Control) commands transmitted by the network node/eNodeB. Power control can also be linked to the modulation and coding scheme used for uplink transmissions.

Here, P ₀ denotes the control value of the open loop part, α is a parameter between 0 and 1, and PL denotes the path loss correction. The uplink power control for PUSCH and PUCCH is discussed below. Uplink power control is used on both PUSCH and PUCCH. The aim is to ensure that the UE or terminal or mobile terminal transmits with a power that is high enough but not too high, as the latter would increase interference to other users in the network as well as drain the battery of the terminal. In both cases, a parameterized open loop combined with a closed loop mechanism can typically be used. In general, the open loop part is used to set the operating point around which the closed loop component operates. Different parameters (targets and "partial compensation factors") can be used for the user plane and the control plane.

In more detail, for PUSCH, the terminal sets the output power according to the following formula:

P _PUSCHc (i)=min{P _MAXc , 10log ₁₀ (M _PUSCHc (i))+

P _{O_PUSCHc} (j)+α _c ·PL _c +Δ _TFc (i)+f _c (i)} [dBm],

where P _MAXc is the maximum transmit power of the mobile terminal, M _PUSCHc (i) is the number of assigned resource blocks, P _{O_PUSCHc} (j) and α _c control the target received power, PL _c is the estimated path loss, Δ _TFc (i) is the transport format compensator, and f _c (i) is the UE-specific offset or "closed-loop correction" (the function f _c can represent an absolute offset or a cumulative offset). The index c numbers the component carrier and is relevant for carrier aggregation cases.

Closed-loop power control can operate in two different modes: cumulative or absolute. Both modes are based on TPC (Transmit Power Control), which can be represented by commands as part of the downlink control signaling. When using absolute power control, the closed-loop correction function is reset each time a new power control command is received. When using cumulative power control, the power control command is an incremental correction relative to the previously accumulated closed-loop correction.

The accumulated power control command is defined as

f _c (i)＝f _c (i-1)+δ _PUSCHc (iK _PUSCH ),

where δ _PUSCHc represents the TPC command received in K _PUSCH subframes before the current subframe i, and f _c (i-1) is the accumulated power control value.

Absolute power control has no memory, so

It can be assumed that f _c (i) = δ _PUSCHc (iK _PUSCH ) holds.

PUCCH power control has the same configurable parameters in principle, except that PUCCH only has full path loss compensation, ie, only covers the case of α=1.

The configured transmit power _PCMAX is described below. The configured transmit power _PCMAX can be defined as follows: the UE is allowed to set the configured maximum output power _PCMAX,c of the UE for the serving cell c. The configured maximum output power _PCMAX,c is set within the following boundaries:

_{PCMAX_L,c} ≤PCMAX _{,c ≤PCMAX_H,c} where

P _{CMAX_L,c} =MIN{P _EMAX,c –ΔT _C,c ,P _PowerClass –MAX(MPR _c +A-MPR _c +ΔT _IB,c +ΔT _C,c ,P-MPR _c )}

P _{CMAX_H,c} =MIN{P _EMAX,c ,P _PowerClass }

in

_-PEMAX,c is the value given by IE P-Max for serving cell c;

-P _PowerClass is the maximum UE power specified in the standard without considering the tolerance specified in the standard;

- _MPRc and A-MPRc for serving cell _c are specified in subclauses 6.2.3 and 6.2.4 respectively;

- ΔT _IB,c is the additional margin for serving cell c as specified in Table 6.2.5-2; otherwise ΔT _IB,c = 0 dB;

- When Note 2 in Table 6.2.2-1 applies, ΔT _C,c = 1.5 dB;

- When Note 2 in Table 6.2.2-1 is not applicable, ΔT _C,c = 0 dB.

P-MPR _c is the maximum output power reduction permitted for:

a) Ensure compliance with applicable electromagnetic energy absorption requirements and address requirements for unwanted radiation/self-sensitivity degradation in the case of simultaneous transmission on multiple RATs in scenarios that are not within the scope of the 3GPP RAN specifications;

b) Where proximity detection is used to address such requirements requiring a lower maximum output power, ensure compliance with applicable electromagnetic energy absorption requirements.

The UE shall apply P-MPR _c for serving cell c only for the above case. For UE conducted conformance testing, P-MPR shall be 0 dB.

P-MPR _c is introduced into the _PCMAX,c equation so that the UE can report the maximum available output transmit power to the eNB. This information can be used by the eNB for scheduling decisions.

P-MPR _c may affect the maximum uplink performance of the selected UL transmission path.

For each subframe, _{PCMAX_L,c} for serving cell c is evaluated per slot and is given by the minimum value taken over the transmissions within that slot; the minimum _{PCMAX_L,c} over both slots is then applied for the entire subframe. The UE shall not exceed _PPowerClass during any time period.

The measured configured maximum output power P _UMAX,c shall be within the following bounds:

_{PCMAX_L,c} –MAX{ _TL ,T( _{PCMAX_L,c} )}≤PUMAX _{, c≤PCMAX_H,c} +T( _{PCMAX_H,c} ) where T( _PCMAX,c ) is defined by the tolerance table below and applies to _{PCMAX_L,c} and _{PCMAX_H,c} respectively, and _TL is the absolute value of the lower tolerance in Table 6.2.2-1 for the applicable operating band.

Table 6.2.5-1: _PCMAX tolerance

For a terminal or UE supporting inter-band carrier aggregation configuration with uplink assigned to one E-UTRA band, ΔT _IB,c is defined for the applicable bands in Table 6.2.5-2.

The existing _PCMAX definition only covers the synchronized multi-carrier case, i.e., when two or more UL carriers are time-synchronized or their transmission time difference is typically very small, such as within the CP length. However, due to independent timing advance commands (e.g., pTAG and sTAG), the UL transmission time difference (Δμ) between CCs in a combined carrier (CA) may become larger. The maximum allowed UL time difference may be limited to approximately 32.5 μs, as defined in Section 7.9 of TS 36.133 V12.5.0.

Even if the maximum UL time difference is as high as 32.5 μs or in this order, a UE in CA or synchronous DC operation can still perform UL power control based on the existing _PCMAX parameter.

However, in non-synchronized DC operation with a receive time difference (Δτ) of approximately ±500 μs, the UE may have to transmit signals on CCs belonging to both the SCG and MCG outside the existing transmit timing window of 32.5 μs. For example, due to the independent TA commands that the UE must apply on the UL CCs (i.e., TA1 for CCs in the MCG and TA2 for CCs in the SCG), the magnitude of Δμ may be 500 μs or larger. When the UL transmit timing of a CC is shifted by more than 32.5 μs, current power control requirements, including how the UE derives _PCMAX on the CC, are not suitable.

A method for operating a wireless communication network and a node and a terminal for asynchronous dual connectivity are described, comprising:

(1) Defines a method for calculating subframe pairs for dual connectivity

(2) Defines the method for calculating _PCMAX on a subframe basis and a time slot basis

(3) Method for enhancing _PCMAX definition based on network guidance

(4) A method for adapting between a first method or scheme and a second method or scheme to obtain _PCMAX according to whether the UE is configured in asynchronous DC operation or synchronous DC operation.

In one embodiment, the method configured or being configured in a UE in a DC comprises the following steps:

obtaining information about a synchronization level at which the UE is configured to operate in the DC;

if the magnitude of the synchronization level is above a threshold (e.g., 200 μs), determining which of the subframes or time slots of the at least partially overlapping pair of subframes or time slots belonging to different CGs (i.e., MCG and SCG) is leading in time;

Calculating or deriving _PCMAX for each CG based at least on the determined leading subframe or time slot;

Based on the calculated or obtained value of _PCMAX for each CG, an uplink signal is transmitted in each CG.

In another embodiment, a method configured or being configured in a UE in a DC comprises the following steps:

- obtain information about the synchronization level at which the UE is configured to operate in DC;

- selecting between a first method and a second method for calculating or deriving _PCMAX based on the level of synchronization information obtained;

- Calculate or obtain _PCMAX based on the selected method;

- Based on the calculated or obtained value of _PCMAX for each CG, transmit an uplink signal in each CG.

In this description, the configured transmit power for the asynchronous dual connectivity scheme is defined. In addition, some enhancements to the _PCMAX definition are proposed.

The terminal or UE behavior with respect to the _PCMAX to be used for transmitting UL signals in each CG is well specified and consistent for all UEs.

Available UE output power can be used more efficiently.

In this section, we mainly describe a system with dual links (dual connectivity with one MCG and one SCG). In general, the solutions described in this disclosure can be easily applied to situations with multiple connectivity (eg, with more than one secondary cell group).

The general term "network node" may be used, which may correspond to any type of radio network node or any network node that communicates with a UE and/or with another network node. Examples of network nodes are NodeB, MeNB, SeNB, a network node belonging to an MCG or SCG, a base station (BS), a multi-standard radio (MSR) radio node (such as an MSR BS), an eNodeB, a network controller, a radio network controller (RNC), a base station controller (BSC), a relay, a donor node controlled relay, a base transceiver station (BTS), an access point (AP), a transmission point, a transmission node, an RRU, an RRH, a node in a distributed antenna system (DAS), a core network node (e.g., an MSC, an MME, etc.), an O&M, an OSS, a SON, a positioning node (e.g., an E-SMLC), an MDT, etc.

The term terminal or user equipment (UE) may be used to refer to any type of wireless device that communicates with a network node and/or with another terminal or UE in a cellular communication system or a mobile communication system. Examples of a terminal or UE are a target device, a device-to-device (D2D) UE, a machine-type UE or a UE with machine-to-machine (M2M) communication capabilities, a PDA, a PAD, a tablet, a mobile terminal, a smartphone, a laptop embedded device (LEE), a laptop mounted device (LME), a USB dongle, etc.

Methods for operating a terminal or UE to determine subframe pairs and reference subframes are described.

For dual connectivity, the following are possible:

1. SFN alignment (synchronization to a common timing/frequency reference) between the MCG and SCG may be impossible, and/or

2. There may be a significant or maximum reception timing difference between the subframe-level signals from the MeNB (as an example of the primary network node) and the SeNB (as an example of the secondary network node); for example, a maximum of 500 μs; this may cause the signals received or transmitted by the terminal via the MCG associated with the primary network node in the dual connection to be out of sync with the signals received or transmitted by the terminal via the SCG associated with the secondary network node.

As shown in Figure 3, due to timing differences, there are mainly three possibilities for subframe boundary mismatch between the signals received or transmitted from the MCG and SCG at the UE, namely:

(1) When the mismatch is less than a maximum value of, for example, 500 μs (by extension, this includes the synchronous case)

(2) when the mismatch is larger than a maximum value of, for example, 500 μs (relating to the start of a subframe in the time domain), and

(3) When the mismatch is exactly at the maximum threshold of, for example, 500 μs (this is a truly theoretical case with a very small probability, on the order of 0.2%).

Due to the possibility of these different subframe boundary mismatches, the UE needs to _{derive PCMAX} for non-synchronous DC operation based on information and/or rules received from at least one network node. The terminal or UE in non-synchronous DC operation uses the derived _PCMAX value for transmission in the UL and/or for performing UL power control. The principles explained in the previous section can also be applied to non-synchronous DC operation for arbitrary "Δτ" values. They can also be generally applied to any kind of DC operation.

To define _PCMAX for dual connectivity, two subframes to be compared with each other may be identified, one subframe each in the MCG and the SCG.

FIG3 shows different levels of subframe timing mismatch between subframes in MCG and SCG, respectively.

Based on the illustration in FIG3 , finding the subframe pairs that should be considered for _PCMAX definition can be challenging.

In general, a subframe pair may comprise two reference subframes (one each in the MCG and SCG), which should be considered together for the purpose of defining _PCMAX . In the case of Figure 4(a), subframe i in the MCG and subframe j in the SCG constitute a subframe pair. Similarly, subframe i in the MCG and subframe j-1 in the SCG constitute the subframe pair in Figure 4(b). To form a subframe pair, the UE considers subframes in the MCG and SCG whose slot 1 (i.e., the first slot in a subframe) overlaps with each other. In this way, always the start of a subframe is considered for forming a subframe pair. In general, a pair of subframes to be compared may be defined, which comprises a subframe from and/or according to the MCG and a subframe from and/or according to the SCG. The slot 1 of one of the subframes of the MCG or SCG may be selected. As the associated subframe of the pair, a subframe of the other group (SCG or MCG, respectively) may be selected whose slot 1 overlaps with the selected slot 1. The selected time slot 1 may be selected from a cell group (MCG or SCG) that is ahead in time.For comparison, the portion of the subframe that overlaps with the selected time slot 1 may be considered.

Based on these discussions, _PCMAX can be derived based on the following main principles:

1. Subframes in one CG that overlap with subframes in another CG in their respective time slots 1 should be paired together between CGs.

2. The leading CG is always used as a reference subframe, i.e., its subframe is ahead in time compared to the other subframe in the subframe pair. The reference subframe can be the subframe for which the terminal/UE calculates the _PCMAX per terminal/UE for its application. This is explained by the following example:

a. If subframe p and subframe q are subframe pairs between MCG and SCG respectively, then

I. If MCG is ahead, subframe p in MCG and subframes q-1 and q in SCG are considered for _PCMAX definition, i.e., for obtaining the value of _PCMAX .

II. If the SCG is ahead, subframes p and p-1 in the MCG and subframe q in the SCG are considered for _PCMAX definition, ie, for obtaining the value of _PCMAX .

The following discusses a method in a UE to define _PCMAX by calculation on a subframe basis. For asynchronous dual connectivity, the following subframes can be considered:

Table 1:

CG MCG Lead SCG leads MCG P p-1,p SCG q-1,q q Reference subframe P q

Table 1 shows the reference subframes and subframe numbers in a subframe pair used for _PCMAX definition or determination. It briefly summarizes the example subframe pairs shown in Figures 4(a) and (b). In the first case (i.e., MCG leads), the p-th subframe in the MCG is the reference subframe, while in the second case (i.e., SCG leads), the q-th subframe in the SCG is the reference subframe. The reference subframe is the subframe in which the calculated per-UE _PCMAX is applied.

The total configured maximum output power _PCMAX can be set within the following boundaries:

P _{CMAX_L} ≤P _CMAX ≤P _{CMAX_H}

in

Here, when MCG leads and SCG leads, respectively, the above _PCMAX is applied to the reference subframes, i.e., to the pth subframe and the qth subframe. _{PCMAX_L,a(b)} and _{PCMAX_H,a(b)} are the lower and upper limits _{of PCMAX,c} for CG a in subframe b, respectively.

_{PCMAX_L,a(b)} is defined as:

Wherein p _EMAX,c∈a , Δt _C,c∈a , Δt _IB,c∈a and other parameters in the above equations are defined for subframe b of serving cell c in CG a .

Similarly, _{PCMAX_H,a(b)} is defined as:

Once _PCMAX is defined, the configured maximum output power Pumax measured per UE for the reference subframe may be defined.

The following describes a method in a UE that defines _PCMAX by calculating it on a slot basis. In one variation, _PCMAX calculation can be performed on a slot basis rather than a subframe level. The principles described above for calculating _PCMAX on a subframe level also apply to calculating _PCMAX on a slot basis. The calculated or derived _PCMAX is also applied by the UE to a reference subframe for UL transmission, which is the subframe containing the first slot of the leading CG.

FIG3 shows an example of _PCMAX calculation based on time slots.

As shown in Figure 3, _{PCMAX_L} can be defined as:

Similarly, _{PCMAX_H} can be defined as:

In the above two equations, _{PCMAX_L,a(b,c)} and _{PCMAX_H,a(b,c)} represent the lower and upper _PCMAX in subframe b and slot c for CG a.

The following describes a method used in the UE to enhance the _PCMAX definition.

In the Rel-12 LTE system, the MeNB provides guidance to the UE regarding the ratio _{of PCMAX} that should be assigned for signal transmission to the MeNB and the remaining power for signal transmission to the SeNB.

For example, the MeNB may configure one or more parameters to the terminal or UE via higher layer signaling to transmit power up to a certain limit in each CG, such as U% and V% of the total UE transmit power for MCG and SCG, respectively. Here, U+V=100.

The UE is configured with a ratio of _PCMAX in different CGs or similar parameters (eg, U, V, etc. as described above) for transmission in MCG and SCG, regardless of whether the UE operates in a sync DC or an unsync DC scenario.

In this case, _PCMAX in each CG is further calculated or obtained or adjusted by considering a ratio of _PCMAX or a similar parameter. Then, the UE transmits using the obtained _PCMAX value in each CG.

Regardless of whether the UE is configured to operate in non-synchronized DC or synchronous DC operation, further adaptation of _PCMAX is performed by the UE in response to the ratio of _PCMAX in different CGs obtained or similar parameters. The further adaptation of _PCMAX is described as follows:

α can be expressed as the ratio for P _MeNB and P _SeNB (the configured maximum transmit power of the respective MeNB and SeNB; in particular for UL transmission of the terminal/UE), where

P _MeNB = αP _PowerClass

P _SeNB = (1-α)P _PowerClass

And α may be any value between 0 and 1 (corresponding to U and V as previously described). _PPowerClass may generally refer to the available/allowable power for a given class of terminals or UEs as defined by the relevant standards.

Assuming that x=MeNB and y=SeNB as follows, when MCG is leading, _{PCMAX_L,x} and _{PCMAX_L,y} can be defined as:

P _{CMAX_L,x} =MIN{P _MeNB ,P _{CMAX_L,x} (p),Δ ₁ }

P _{CMAX_L,y} =MIN{P _SeNB ,P _{CMAX_L,y} (q-1),P _{CMAX_L,y} (q),Δ ₂ }

in

Δ ₁ =MIN{P _{CMAX_L,y} (q-1),P _{CMAX_L,y} (q)}-P _SeNB

Δ ₂ =P _{CMAX_L,x} (p)-P _MeNB (5.4-1)

Similarly, when SCG is leading, _{PCMAX_L,x} and _{PCMAX_L,y} can be defined as:

P _{CMAX_L, x} = MIN { P _MeNB , P _{CMAX_L, x} (p-1), P _{CMAX_L, x} (p), Δ ₁ }

P _{CMAX_L,y} =MIN{P _SeNB ,P _{CMAX_L,y} (q),Δ ₂ }

in

Δ ₁ =P _{CMAX_L, y} (q)-P _SeNB

Δ ₂ =MIN{P _{CMAX_L,y} (p-1),P _{CMAX_L,y} (p)}-P _MeNB (5.4-2)

In case of synchronous DC operation, the UL subframes in both MCG and SCG do not lead each other but are time aligned or within some limit such as 33μ8.In synchronous DC operation, _PCMAX adaptation can be based on either of the above two criteria (5.4-1 and 5.4-2).

Methods for adapting _PCMAX calculations in a UE or for operating a UE based on synchronization levels are discussed below. A DC-capable UE and/or a terminal adapted for DC may be configured with different levels of synchronization by a network node (e.g., a master network node). For example, a UE capable of operating in both an unsynchronized DC scenario or a synchronized DC scenario may be configured with or configured for unsynchronized DC operation or synchronized DC operation by a network node. The network node may be adapted to configure a terminal with different synchronization levels, the terminal may be adapted for DC with an MCG and an SCG and/or in dual connectivity with an MCG and an SCG.

In yet another embodiment, the terminal or UE adapts between the first method and the second method for calculating or deriving _PCMAX based on the synchronization level at which the UE is configured to operate in DC. For example, the terminal or UE:

- a first method for calculating or deriving _PCMAX may be applied when configured to operate in synchronous DC, wherein the first method is the existing method described above for synchronous operation (i.e., section 6.2.5 of 3GPP TS 36.101), and

- A second method for calculating or deriving _PCMAX may be applied when configured to operate in asynchronous DC, wherein the second method is the existing method described in the previous section for subframe-based or slot-based asynchronous operation.

Regardless of the synchronization level, the terminal or UE may further adapt _PCMAX in response to the ratio of _PCMAX in different CGs obtained as described above or similar parameters.The UE then transmits in each CG using the _PCMAX value obtained for each CG.

To apply the method disclosed in this embodiment, a terminal or UE configured or being configured as a DC may perform the following simplest steps:

- obtaining information about the synchronization level at which the UE is configured to operate in DC, the synchronization level comprising (e.g., by an acquisition module of the terminal or UE) time differences of signals received from different CGs (e.g., MCG and SCG);

- selecting between a first method and a second method for calculating or deriving _PCMAX based on the information obtained (e.g., by a selection module of the terminal or UE);

- Calculating or obtaining _PCMAX based on the selected method (e.g., by a calculation module of the terminal or UE); the selection module and the calculation module may be integrated into a determination module for determining _PCMAX . This can be considered as an implementation of the method for operating a terminal. A terminal suitable for performing the method can be considered.

Alternatively or additionally, a method for operating a terminal in a wireless communication network, the terminal being adapted for dual connectivity, may be considered. The terminal may be connected to a primary network node via a primary cell group (MCG) and to a secondary network node via a secondary cell group (SCG). The method may include obtaining synchronization information, in particular information regarding a time difference between signals from the MCG and the SCG, by the terminal. The method may also include determining _PCMAX based on the synchronization information. Determining _PCMAX based on the synchronization information may include selecting a method for determining _PCMAX based on a synchronization level, in particular selecting between a first method and a second method as described herein. The second method may be slot-based or subframe-based as described herein. Alternatively or additionally, determining _PCMAX may include calculating _PCMAX based on the selected method. The method may include performing an UL transmission based on the determined _PCMAX .

Generally a terminal may be considered that is adapted to perform any one or more than one of the methods for operating a terminal as disclosed herein.

Alternatively or additionally, a terminal for a wireless communication network may be considered, the terminal being adapted for dual connectivity. The terminal may be adapted for and/or include a connection module configured to connect or be connectable to a primary network node via a primary cell group (MCG) and to connect to a secondary network node via a secondary cell group (SCG). The terminal may be adapted for and/or include an acquisition module configured to acquire synchronization information, in particular information regarding the time difference between signals from the MCG and the SCG.

It is contemplated that the terminal may be adapted to and/or may include a determination module for determining _PCMAX based on synchronization information. Determining _PCMAX based on the synchronization information may include selecting a method for determining _PCMAX based on the synchronization level, in particular, for example, selecting between the first method and the second method described herein by a selection module of the terminal. Alternatively or additionally, determining _PCMAX may include calculating _PCMAX based on the selected method, for example, by a calculation module.

The terminal may optionally be adapted to perform UL transmission based on the determined _PCMAX and/or include a transmission module for performing UL transmission based on the determined _PCMAX .

A method of operating a network node (particularly a primary network node and/or a secondary network node) may be contemplated. The network node may be in dual connectivity with a terminal. The method may include obtaining, by the network node, synchronization information related to a time difference between signals from a MCG and an SCG configured for the terminal. The method may also include transmitting the obtained synchronization information to the terminal.

A network node for a wireless communication network may be considered, in particular a master network node and/or a slave network node. The network node may optionally be adapted for dual connectivity with a terminal and/or comprise a connection module for dual connectivity with a terminal.

The network node may be adapted to obtain synchronization information related to the time difference between signals from the MCG and SCG configured for the terminal, and/or include an obtaining module configured to obtain synchronization information related to the time difference between signals from the MCG and SCG configured for the terminal. It is contemplated that the network node may also be adapted to transmit the obtained synchronization information to the terminal, and/or include a transmitting module configured to transmit the obtained synchronization information to the terminal.

Generally, any terminal and/or network node described herein may include circuitry, in particular control circuitry and/or radio circuitry, configured to perform the respective method described and/or provide the described functionality.

Obtained by the terminal or UE and/or network node may include: determining or obtaining synchronization information, and/or information related to the synchronization level at which the UE is configured to operate in DC, and/or autonomously with the time difference between the MCG signal and the SCG signal (e.g., based on the reception time difference of the signal from the CG and/or the signal transmitted via the CG), and/or receiving an indication from the network (e.g., one of the network nodes, such as a primary network node or a secondary network node).

The configured transmit power for dual connectivity is discussed below.

Independently or in addition to the above, consideration may include:

For dual connectivity with one uplink carrier per cell group, the UE or terminal may be allowed and/or adapted and/or include a power setting module adapted to set and/or set its configured maximum output power _PCMAX,c,x and _PCMAX,c,y on each serving cell group x and y, as well as its total configured maximum output power _PCMAX . The UE or terminal may be allowed and/or adapted and/or include a power setting module adapted to comply with and/or perform compliance with any one or any combination of the following conditions and/or regulations.

The total configured maximum output power _PCMAX can or should be set within the following boundaries:

P _{CMAX_L} ≤P _CMAX ≤P _{CMAX_H}

When synchronized transmission occurs between cell group uplink serving cells, _{PCMAX_L} and _{PCMAX_H} may be standardly defined, for example, in subclause 6.2.5A of TS 36.101 for the carrier aggregation inter-band case.

If a UE or terminal is configured in dual connectivity for a synchronous scenario, and the UE or terminal's transmission on subframe p for any serving cell in one cell group overlaps with some portion of the first symbol of a transmission on subframe q+1 for a different serving cell in another cell group (where subframe p and subframe q are a subframe pair between the MCG and SCG, respectively), then the UE or terminal minimum value _{PCMAX_L} for subframe pairs (p,q) and (p+1,q+1) applies to any overlapping portion of subframes (p,q) and (p+1,q+1), respectively. It is considered that the UE or terminal should not exceed _PPowerClass during any time period.

When asynchronous overlapping transmission occurs, subframes in one CG that overlap with subframes in another CG in their corresponding time slot 1 should be paired together between the CGs. The terminal can be adapted for such pairing and/or include a corresponding pairing module. The leading CG can be used as a reference subframe, that is, its subframe is ahead in time compared to the other subframe in the subframe pair. The terminal or UE can be adapted to determine the reference subframe in this way and/or include a corresponding reference module. The reference subframe is the subframe of the _PCMAX per terminal or UE calculated by the UE or terminal application, which can be adapted and/or include a corresponding _PCMAX application module and/or calculation module accordingly.

If subframe p and subframe q are a subframe pair between MCG and SCG respectively, then

If the MCG is ahead, subframe p in the MCG and subframes q-1 and q in the SCG are considered for _PCMAX definition, ie for obtaining the value of _PCMAX .

If the SCG is ahead, subframes p and p-1 in the MCG and subframe q in the SCG are considered for the _PCMAX definition, ie for deriving the value of _PCMAX .

When non-synchronized overlapping transmission occurs between two cell group uplink serving cells, and the reference subframe p from cell group x overlaps with two consecutive subframes q-1 and q on cell group y (or the reference subframe q from cell group y overlaps with two consecutive subframes p-1 and p on cell group x), the above _{PCMAX_L} and _{PCMAX_H} for the reference subframe p (or reference subframe q) duration are defined as follows:

_{PCMAX_L,x} (P) and _{PCMAX_H,x} (P), _{PCMAX_L,y} (P) and _{PCMAX_H,y} (P) are _{PCMAX_Lc} and _{PCMAX_H,c} for CGx and CGy, respectively, and are defined as follows:

as well as

where P _EMAX,c∈a , Δt _C,c∈a , Δt _IB,c∈a and other parameters in the above equations are defined for subframe b of serving cell c in CG a.

If a single uplink cell is active, the maximum output power _PUMAX, i measured by the UE over all uplink serving cells of cell group i may be defined (see eg subclause 6.2.5 of TS 36.101).

The UE total measured maximum output power P _UMAX for the reference subframe p (or reference subframe q) duration over all serving cells of the two defined cell groups may be defined as follows:

P _UMAX =∑P _UMAX,i

P _{CMAX_L} –T _LOW (P _{CMAX_L} )≤P _UMAX ≤P _{CMAX_H} +T _HIGH (P _{CMAX_H} )

Table 2: _PCMAX tolerance for dual connections

In the context of this description, wireless communication can be, for example, communication (particularly transmission and/or reception of data) via electromagnetic waves and/or an air interface (particularly radio waves) and/or utilizing a radio access technology (RAT) in a wireless communication network. The communication can involve one or more terminals connected to the wireless communication network and/or more than one node in and/or of the wireless communication network. It is contemplated that a node in, of, or used for communication in or for communication in a wireless communication network is adapted to communicate using one or more RATs (particularly LTE/E-UTRA).

Communication may generally involve the transmission and/or reception of messages, particularly in the form of packet data. Messages or packets may include control and/or configuration data and/or payload data and/or represent and/or include a batch of physical layer transmissions. Control and/or configuration data may refer to data related to the process of communication and/or the communicating nodes and/or terminals. For example, address data of the communicating nodes or terminals and/or data related to the transmission mode and/or spectrum configuration and/or frequency and/or coding and/or timing and/or bandwidth may be included as data related to the process of communication or transmission, for example in a header. Each node or terminal involved in the communication may include radio circuitry and/or control circuitry and/or antenna circuitry, which may be arranged to utilize and/or implement one or more radio access technologies. The radio circuitry of a node or terminal may generally be adapted for transmitting and/or receiving radio waves and may in particular include a corresponding transmitter and/or receiver and/or transceiver, which may be connected or connectable to the antenna circuitry and/or control circuitry. The control circuitry of a node or terminal may include a controller and/or a memory, the memory being arranged to be accessible to the controller for read and/or write access. The controller may be arranged to control communication and/or radio circuitry and/or provide additional services. The circuitry of a node or terminal (particularly the control circuitry, such as the controller) may be programmed to provide the functionality described herein.

The corresponding program code can be stored in an associated memory and/or storage medium and/or hardwired and/or provided as firmware and/or software and/or in hardware. The controller can generally include a processor and/or a microprocessor and/or a microcontroller and/or an FPGA (field programmable gate array) device and/or an ASIC (application-specific integrated circuit) device. More specifically, it is contemplated that the control circuit includes and/or can be connected or can be connected to a memory, and the memory can be adapted to be readable and/or writable by the controller and/or the control circuit. The radio access technology can generally include, for example, Bluetooth and/or Wifi and/or WIMAX and/or cdma2000 and/or GERAN and/or UTRAN and/or especially E-Utran and/or LTE. Communication can particularly include physical layer (PHY) transmission and/or reception, on which logical channels and/or logical transmission and/or reception can be imprinted or layered.

A node of a wireless communication network may be implemented as a terminal and/or user equipment and/or a network node and/or a base station (e.g. eNodeB) and/or a relay node and/or generally any device suitable for communicating in a wireless communication network, in particular a cellular communication network.

A wireless communication network or cellular network may include network nodes, in particular radio network nodes, that may be connected or connectable to a core network, such as a core network having an evolved network core according to LTE. The network nodes may, for example, be base stations. The connection between the network nodes and the core network/network core may be based at least in part on a cable/landline connection. Operations and/or communications and/or exchanges of signals involving a portion of the core network, in particular layers above a base station or eNB, and/or via a predefined cell structure provided by the base station or eNB, may be considered to have a cellular nature or referred to as cellular operation.

A terminal may be implemented as a user equipment; a terminal may generally be considered to be suitable for providing and/or defining wireless communications and/or an endpoint for a wireless communication network. A terminal or user equipment (UE) may generally be a device configured for wireless device-to-device communication and/or a terminal for a wireless and/or cellular network, in particular a mobile terminal such as a mobile phone, smartphone, tablet, PDA, etc. For example, if the user equipment or terminal takes over some control and/or relay functions for another terminal or node, it may be a node of or for a wireless communication network as described herein. It is contemplated that the terminal or user equipment may be suitable for one or more RATs, in particular LTE/E-UTRA.

A terminal or user equipment may be considered to include radio circuitry and/or control circuitry for wireless communication. The radio circuitry may include, for example, a receiver device and/or a transmitter device and/or a transceiver device. The control circuitry may include a controller, which may include a microprocessor and/or a microcontroller and/or an FPGA (field programmable gate array) device and/or an ASIC (application-specific integrated circuit) device. The control circuitry may be considered to include, be connected to, or be capable of connecting to a memory, which may be adapted to be readable and/or writable by the controller and/or the control circuitry. The terminal or user equipment may be considered to be configured as a terminal or user equipment suitable for LTE/E-UTRAN. Generally, the terminal may be adapted to support dual connectivity. The terminal may include two independently operable transmitter (or transceiver) circuitry and/or two independently operable receiver circuitry; for dual connectivity, the terminal may be adapted to utilize one transmitter (and/or receiver or transceiver, if provided) for communication with a primary network node and one transmitter (and/or receiver or transceiver, if provided) for communication with a secondary network node. A terminal may be considered to include more than two such independently operable circuits.

A network node or base station (e.g., an eNodeB) can be any type of base station in a wireless network and/or cellular network adapted to serve one or more terminals or user equipment. A base station can be considered a node or network node of a wireless communication network. A network node or base station can be adapted to provide and/or define and/or serve one or more cells of the network and/or allocate frequency and/or time resources for communicating with one or more nodes or terminals of the network. Generally, any node adapted to provide such functionality can be considered a base station. A base station, or more generally, a network node (particularly a radio network node), can be considered to include radio circuitry and/or control circuitry for wireless communication. It is contemplated that a base station or network node can be adapted for one or more RATs, particularly LTE/E-UTRA. The radio circuitry can include, for example, a receiver device and/or a transmitter device and/or a transceiver device. The control circuitry can include a controller, which can include a microprocessor and/or microcontroller and/or an FPGA (field programmable gate array) device and/or an ASIC (application-specific integrated circuit) device. The control circuitry can be considered to include, be connected to, or be capable of connecting to, a memory, which can be adapted to be readable and/or writable by the controller and/or control circuitry. A base station may be arranged as a node of a wireless communication network, specifically configured to enable and/or facilitate and/or participate in cellular communications, for example, as a directly participating device or as an assisting and/or coordinating node. Generally, a base station may be arranged to communicate with a core network and/or provide services and/or control to one or more user devices and/or relay and/or transmit communications and/or data between one or more user devices and the core network and/or another base station. A network node or base station may generally be adapted to allocate and/or schedule time/frequency resources for the network and/or one or more cells served by the base station. An eNodeB (eNB) may be considered an example of a base station according to the LTE standard, for example. A base station may be considered to be configured to connect to or be capable of connecting to an evolved packet core (EPC) and/or to provide and/or connect to corresponding functionality. The functionality and/or multiple different functions of a base station may be distributed across one or more different devices and/or physical locations and/or nodes. A base station may be considered a node of a wireless communication network. Generally, a base station may be considered to be configured as a control node and/or a coordinating node and/or to allocate resources, particularly for cellular communications via one or more cells.

It can be considered that for cellular communication, at least one uplink (UL) connection and/or channel and/or carrier and at least one downlink (DL) connection and/or channel and/or carrier are provided, for example, via and/or defined by a cell, which can be provided by a network node (particularly a base station or eNodeB). The uplink direction can refer to the direction of data transmission from the terminal to the network node (e.g., a base station and/or a relay station). The downlink direction can refer to the direction of data transmission from the network node (e.g., a base station and/or a relay node) to the terminal. UL and DL can be associated with different frequency resources (e.g., carriers and/or spectrum bands). A cell may include at least one uplink carrier and at least one downlink carrier that may have different frequency bands.

A network node (e.g., a base station or eNodeB) may be adapted to provide and/or define and/or control one or more cells (e.g., a cell group), which may be, for example, carrier aggregation (CA) cells. A cell group may include at least one primary cell, which may be considered a member of and/or associated with the group. A cell group may include one or more secondary cells (note that each group may include secondary cells, not just secondary groups; in this context, "secondary" refers to being subordinate to the primary cell of the group). The primary cell may be adapted and/or configured to provide control information (particularly, allocation data and/or scheduling and/or allocation information related to the primary cell and/or cell group) to and/or from terminals connected for communication (transmission and reception) and/or configured with the cell. The control information may be related to the primary cell and/or cell group. Each primary cell and/or associated group may be associated with a specific network node. The primary network node may be adapted to provide and/or serve and/or define the primary cells in the primary cell group. The secondary network node may be adapted to provide and/or serve and/or define the secondary cell group.

The terminal may be adapted to be configured with a primary cell group (at least one primary cell) and/or communicate via the primary cell group (at least one primary cell) for communicating with a primary network node. Additionally, the terminal may be adapted to be configured with a secondary cell group (at least one (secondary) primary cell) and/or communicate via the secondary cell group (at least one (secondary) primary cell) for communicating with a secondary network node; the terminal may generally be adapted for dual connectivity. The terminal may include suitable circuitry, such as a first transmitter circuit and/or receiver circuit and/or transceiver circuit (e.g., for communicating with a primary network node) and a second first transmitter circuit and/or receiver circuit and/or transceiver circuit (e.g., for communicating with a secondary network node).

The network nodes (particularly base stations) and/or terminals (particularly UEs) may be adapted for communicating in spectrum bands (frequency bands) that are authorized and/or defined for LTE.

Resources or communication resources may generally be frequency and/or time resources, which may include, for example, frames, subframes, time slots, resource blocks, carriers, subcarriers, channels, frequency/spectrum bands, etc. Allocated or scheduled resources may include and/or relate to frequency-related information, in particular regarding one or more carriers and/or bandwidths and/or subcarriers; and/or time-related information, in particular regarding frames and/or time slots and/or subframes, and/or information related to resource blocks and/or time/frequency hopping. Transmitting on and/or using the allocated resources may include transmitting data on the allocated resources (e.g., on the indicated frequencies and/or subcarriers and/or carriers and/or time slots or subframes). It may generally be considered that the allocated resources may be released and/or de-allocated. A network or a node of the network (e.g., a network node or an allocation node, such as a base station) may be adapted to determine and/or transmit corresponding allocation or scheduling data, such as data indicating the release or de-allocation of resources and/or the scheduling of UL and/or DL resources. Thus, resource allocation can be performed by the network and/or by a network node; a network node adapted to provide resource allocation/scheduling for one or more terminals can be considered a control node. Resources can be allocated and/or scheduled at the cell level and/or by a network node serving and/or providing a cell.

Allocation data can be considered data indicating and/or granting resources allocated by a network node (e.g., a control and/or allocation node), in particular, data identifying or indicating which resources are reserved or allocated, for example, for cellular communications, which typically includes transmitting and/or receiving data and/or signals. Allocation data can indicate resource grants or releases and/or resource scheduling. A grant or resource grant can be considered an example of allocation data. An allocation node can be considered to be adapted to transmit allocation data to a node directly and/or indirectly, for example, via a relay node and/or another node or base station. The allocation data can include control data and/or be part of a message, or can be formed in accordance with a predefined format (e.g., a DCI format) that may be defined in a standard (e.g., LTE). In particular, the allocation data can include information and/or instructions to reserve resources or release already allocated resources. A terminal can generally be adapted to transmit and/or receive data (e.g., UL data) to and/or to a network node and/or to more than one network node in accordance with the allocation data.

A method for operating a wireless device (e.g., user equipment) is described.

The method includes:

Figure 5 schematically illustrates a terminal 10, which in this example may be implemented as a user equipment. Terminal 10 includes control circuitry 20, which may include a controller connected to a memory. A receiving module and/or a transmitting module and/or a control or processing module and/or a CIS receiving module and/or a scheduling module may be implemented in and/or executed by control circuitry 20, particularly as modules within the controller. Terminal 10 also includes radio circuitry 22, which provides receiving and transmitting or transceiving functionality. Radio circuitry 22 is connected or connectable to the control circuitry. Antenna circuitry 24 of terminal 10 is connected or connectable to radio circuitry 22 for collecting, transmitting, and/or amplifying signals. Radio circuitry 22 and control circuitry 20, which controls it, are configured for cellular communication with a network over a first cell/carrier and a second cell/carrier, particularly utilizing E-UTRAN/LTE resources as described herein. Terminal 10 may be adapted to perform any of the methods for operating a terminal disclosed herein; in particular, it may include corresponding circuitry, such as control circuitry.

Figure 6 schematically illustrates a network node or base station 100, which may be an eNodeB, such as an MeNB or SeNB. Network node 100 includes control circuitry 120, which may include a controller connected to a memory. A reception module and/or a transmission module and/or a control or processing module and/or a scheduling module and/or a CIS reception module may be implemented in and/or executed by control circuitry 120. The control circuitry is connected to control radio circuitry 122 of network node 100, which provides receiver and transmitter and/or transceiver functionality. Antenna circuitry 124 may be connected or connectable to radio circuitry 122 for signal reception or transmission and/or amplification. Network node 100 may be adapted to perform any of the methods for operating a network node disclosed herein; in particular, it may include corresponding circuitry, such as control circuitry.

FIG7 shows an exemplary flow chart of a method for operating a terminal, which may be a terminal as described herein, in particular a terminal configured for and/or having dual connectivity. The method may include an optional act TS8 of obtaining synchronization information, the synchronization information relating to a synchronization level. The method may also include an act TS10 of determining a configured transmit power _PCMAX of the terminal based on the synchronization level.

FIG8 shows an example of a terminal, which may be a terminal as described herein, in particular a terminal configured for and/or having dual connectivity. The terminal may include an optional obtaining module TM8 for performing action TS8. The terminal may also include a determining module TM10 for performing action TS10.

Figure 9 shows an exemplary flow chart of a method for operating a network node, which may be a network node as described herein, in particular a network node configured for and/or in dual connectivity with a terminal. The method may include an act NS10 of obtaining synchronization information regarding a time difference between signals from a primary cell group (MCG) and a secondary cell group (SCG) configured for the terminal. Optionally, the method may include an act NS12 of transmitting the obtained synchronization information to the terminal.

Figure 10 illustrates an example of a network node, which may be a network node as described herein, and in particular, a network node configured or configurable for dual connectivity with a terminal and/or a network node configured in dual connectivity with a terminal. The network node may include an obtaining module configured to perform an action NM10 for obtaining synchronization information regarding a time difference between signals from a primary cell group (MCG) and a secondary cell group (SCG) configured for the terminal. Optionally, the network node may include a transmitting module configured to perform an action NM12 for transmitting the obtained synchronization information to the terminal.

A network node may be considered to be adapted for performing any of the methods for operating a network node described herein.

A terminal may be considered that is adapted to perform any of the methods for operating a terminal described herein.

Also disclosed is a program product comprising code executable by a control circuit, which code, in particular if executed on the control circuit, causes the control circuit to perform and/or control any of the methods for operating a terminal or network node as described herein, which may be the control circuit of a terminal or network node as described herein.

Furthermore, a carrier medium is disclosed that carries and/or stores at least one of the program products described herein and/or code executable by a control circuit, the code causing the control circuit to perform and/or control at least one of the methods described herein. Generally, the carrier medium is accessible and/or readable and/or receivable by the control circuit. Storing data and/or program products and/or code can be considered as a portion that carries the data and/or program products and/or code. The carrier medium can generally include a guide/transmission medium and/or a storage medium. The guide/transmission medium can be adapted to carry and/or store signals, particularly electromagnetic signals and/or electrical signals and/or magnetic signals and/or optical signals. The carrier medium (particularly the guide/transmission medium) can be adapted to guide these signals in order to carry them. The carrier medium (particularly the guide/transmission medium) can include an electromagnetic field (e.g., radio waves or microwaves) and/or a light-transmitting material (e.g., fiberglass and/or cable). The storage medium can include at least one of a volatile or non-volatile memory, a buffer, a cache, an optical disk, a magnetic storage device, a flash memory, and the like.

The cell group may alternatively be referred to as a carrier group, in particular since each cell comprises one or more carriers (in the present context, a carrier may refer to a carrier frequency and/or a frequency band used for wireless transmission, in particular a carrier frequency and/or a frequency band used for wireless transmission according to a telecommunication standard such as LTE.

The terminal and/or the network node may be adapted to support dual connectivity and/or include a connectivity module for supporting dual connectivity. For example, the terminal and/or its connectivity module may be adapted to communicate with more than one network node, in particular to transmit and/or receive control and/or scheduling and/or allocation data, wherein one of the network nodes may be a primary network node and at least one other node may be a secondary node.

The primary network node and/or its connection module can be adapted to control the functions of the secondary network node in dual connectivity, in particular switching between secondary network nodes; the primary network node and/or its connection module can be adapted to transmit and/or receive corresponding control signaling to and/or from the secondary network node, for example, via a backhaul and/or communication interface (e.g., an X2 interface).

The network node may typically include a corresponding backhaul and/or communication interface. The backhaul may be considered non-ideal, i.e., it may have high latency (high latency may be a latency that is too high to perform real-time control and/or provide synchronization scheduling and/or allocation of resources by the primary network node for communication between the secondary network node and the terminal; alternatively or additionally, high latency may be a latency that is higher than a predetermined high latency threshold that may depend on the implemented system and/or standard (e.g., LTE). Alternatively, the backhaul may be considered ideal, allowing (in principle) such real-time control. The secondary network node and/or its connection module may be adapted to receive control information from the primary network node. The primary network node may typically be adapted to function as a secondary network node for, for example, another terminal, and vice versa.

A terminal configured with a cell and/or a carrier and/or connected to a network node via a cell may be in a state in which it can communicate using the cell or carrier (e.g., transmit and/or receive data with the network node), e.g., register with the network for communication and/or synchronize with the cell and/or carrier; in particular, the cell may be activated for the terminal.

The terminal may be adapted to perform an activation procedure, wherein it activates a cell based on a timing message and/or timing parameters received from a network node that provides and/or serves and/or defines and/or schedules the cell. The activation procedure may be part of an access procedure, in particular a random access procedure.

The access procedure/request may generally be a random access procedure as described herein, such as a random access procedure with contention resolution or without contention, which may be performed between a terminal and/or a network node to access and/or time-align and/or activate a cell for the terminal, the cell being provided and/or served and/or defined and/or controlled by the network node and/or associated with the network node.

The activation procedure may include an access procedure. It should be noted that if the terminal is unable to activate the cell, for example due to unfavorable reception conditions, the result of the performed access or activation procedure may be a failure.

Synchronization information may generally relate to information relating to, for example, the time difference between signals from a primary network node (via an MCG) and a secondary network node (e.g., via an SCG), and/or information relating to the time difference between signals received by a terminal via an MCG and an SCG, in particular via respective primary cells (PCell and PSCell) . Synchronization information may refer to and/or include a synchronization level. The synchronization level may indicate whether the time difference (or its absolute value) is above a given threshold and/or between given thresholds, e.g., whether it is greater than a threshold defining a synchronized signal. Typically, the synchronization level may indicate a predetermined type or mode of synchronization in a dual connection as discussed herein. One or more thresholds may be defined as above with respect to the synchronization type. The synchronization information may additionally or alternatively include a value and/or an absolute value of the time difference. Examples of synchronization levels include synchronous and asynchronous (also referred to as synchronous and asynchronous).

Configuring the terminal or UE by the network or network node may include: transmitting one or more parameters and/or commands to the terminal or UE by the network or network node, and/or the terminal or UE changing its configuration and/or settings based on the parameters and/or commands received from the network and/or network node.

Some useful abbreviations include:

Abbreviation Explanation

CCA Clear Channel Assessment

DCI Downlink Control Information

DL Downlink

DMRS Demodulation Reference Signal

eNB evolved NodeB, base station

TTI Transmission Time Interval

UE User Equipment

UL Uplink

LA Authorization Assistance

LA Authorization Assisted Access

DRS Discovery Reference Signal

SCell Secondary Cell

SRS Sounding Reference Signal

LBT Listen before speaking

PCFICH Physical Control Format Indicator Channel

PDCCH Physical Downlink Control Channel

PUSCH Physical Uplink Shared Channel

PUCCH Physical Uplink Control Channel

RRM Radio Resource Management

CIS transmission confirmation signal

3GPP Third Generation Partnership Project

Ack/Nack Confirmation/Negation (also A/N)

AP Access Point

B1, B2, ..., Bn signal bandwidth, in particular the carrier bandwidth Bn assigned to the respective carrier or frequency f1, f2, ..., fn

BER/BLER Bit Error Rate/Block Error Rate;

BS Base Station

Carrier Aggregation (CA)

CC Component Carrier (Carrier in Carrier Aggregation)

CoMP Coordinated Multipoint Transmission and Reception

CQI Channel Quality Information

CRS Cell-specific reference signal

CSI Channel State Information

CSI-RS CSI reference signal

D2D device to device

DL Downlink

EPDCCH Enhanced Physical DL Control Channel

DL Downlink; generally data transmission to nodes/directions (physically and/or logically) further away from the network core; in particular, from a base station or eNodeB to a D2D-enabled node or UE; typically uses a different designated spectrum/bandwidth than UL (e.g., LTE)

eNB Evolved NodeB; a form of base station, also known as eNodeB

E-UTRA/N Evolved UMTS Terrestrial Radio Access/Network, example of RAT

f1, f2, f3, ..., fn carrier/carrier frequency; different numbers can indicate different reference carriers/frequencies

f1_UL, ..., fn_UL for uplink/carriers in the uplink frequency or frequency band

f1_DL, ..., fn_DL for downlink/carriers in downlink frequency or band

FDD Frequency Division Duplex

ID

L1 Layer 1

L2 Layer 2

LTE Long Term Evolution, telecommunications standard

MAC Media Access Control

MBSFN Multi-Broadcast Single Frequency Network

MDT Minimized Drive Test

MME Mobility Management Entity; a control entity in a wireless communication network (LTE) that provides control functions for radio network nodes such as eNBs

NW Network

OFDM Orthogonal Frequency Division Multiplexing

O&M Operations and Maintenance

OSS Operation Support System

PC Power Control

PCell Primary cell (e.g. in CA, especially the primary cell of a primary cell group)

PDCCH Physical DL Control Channel

PH Power Headroom

PHR Power Headroom Report

Pscell: the primary cell of the secondary cell group

PSS Primary Synchronization Signal

PUSCH Physical Uplink Shared Channel

R1, R2, ..., Rn resources, in particular time-frequency resources, in particular assigned to corresponding carriers f1, f2, ..., fn

RA Random Access

RACH Random Access Channel

RAN Radio Access Network

RAT Radio Access Technology

RE resource element

RB Resource Block

RRH Remote Radio Head

RRM Radio Resource Management

RRU Remote Radio Unit

RSRQ Reference Signal Received Quality

RSRP Reference Signal Received Power

RSSI Received Signal Strength Indicator

RX Receive/Receiver, receive related

SA Scheduling Allocation

SCell Secondary cell (e.g. in CA)

SINR/SNR Signal-to-noise-interference ratio; signal-to-noise ratio

SFN Single Frequency Network

SON self-organizing network

SSS Secondary synchronization signal

TPC Transmit Power Control

TX transmission/transmitter, transmission related

TDD Time Division Duplex

UE User Equipment

UL Uplink; generally refers to the transmission of data towards a node/direction that is (physically and/or logically) close to the core of the network; in particular, from a D2D-capable node or UE to a base station or eNodeB; in the context of D2D, it may refer to the spectrum/bandwidth used for transmissions in D2D, which may be the same as the UL communication of an eNB in cellular communications; in some D2D variants, transmissions of all devices participating in the D2D communication may typically be in the UL spectrum/bandwidth/carrier/frequency in some variants.

DC Dual Connection

MCG Master Cell Group

SCG Secondary Cell Group

PCell Primary Cell

PSCell Primary SCell

SCell Secondary Cell

RACH Random Access Channel

These and other abbreviations may be used as defined by the LTE standards.

Claims (5)

1. A method for operating a terminal (10) in a wireless communication network, the terminal (10) being adapted for dual connectivity, the method comprising: determining a total configured maximum output power P _{_CMAX} of the terminal (10) based on a synchronization level. The terminal (10) is connected to the primary network node (100) via the primary cell group (MCG) and to the secondary network node via the secondary cell group (SCG). Wherein, when the subframe p of the MCG overlaps with the subframe q of the SCG such that the first time slot of the subframe p overlaps with the first time slot of the subframe q, and the subframe p is ahead of the subframe q in time, the subframe p of the MCG is defined as a reference subframe, and _{the PCMAX} for the reference subframe is determined by taking into account the subframe q-1 and the subframe q of the SCG. 2. The method of claim 1, wherein the method includes obtaining synchronization information relating to the synchronization level. 3. A terminal (10) for a wireless communication network, the terminal (10) being adapted for dual connectivity, the terminal (10) being further adapted to determine a total configured maximum output power _PCMAX of the terminal (10) based on a synchronization level, the terminal (10) being connected to or connectable to a primary network node (100) via a primary cell group (MCG) and connected to or connectable to a secondary network node via a secondary cell group (SCG). The terminal (10) is further adapted to: define subframe p as a reference subframe when subframe p of the MCG overlaps with subframe q of the SCG such that the first time slot of subframe p overlaps with the first time slot of subframe q, and subframe p is ahead of subframe q in time, and determine _{the PCMAX} for the reference subframe by taking into account subframe q-1 and subframe q of the SCG. 4. The terminal according to claim 3, wherein the terminal (10) is further adapted to obtain synchronization information relating to the synchronization level. 5. A computer-readable storage medium storing control circuit executable code that, when executed on the control circuit, causes the control circuit to perform and/or control any one of the methods according to claims 1-2.