BACKGROUND

TECHNICAL FIELD

[0001] The exemplary and non-limiting embodiments relate generally to wireless communication and, more particularly, to preventing interrupts on active cell operation.

BRIEF DESCRIPTION OF PRIOR DEVELOPMENTS

[0002] This section is intended to provide a background or context to the invention disclosed below. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived, implemented or described. Therefore, unless otherwise explicitly indicated herein, what is described in this section is not prior art to the description in this application and is not admitted to be prior art by inclusion in this section.

[0003] The following abbreviations that may be found in the specification and/or the drawing figures are defined as follows:

3GPP 3rd generation partnership project

ack acknowledgement

CA carrier aggregation

CC component carrier

CIF carrier indicator field

DC dual connectivity

DL downlink (from base station to UE)

eNB, eNodeB evolved node B/base station in an E-UTRAN system

E-PDCCH enhanced physical downlink control channel

E-UTRAN evolved universal terrestrial radio access network (LTE)

HetNet heterogeneous network

HO handover

IF inter-frequency

LTE long term evolution

LTE-A long term evolution advanced

MHz mega-Hertz

MR measurement report

ms millisecond

nack or nak Non-acknowledgement

PCC primary component carrier

PCI physical cell identity Pcell or PCell primary cell

PDCCH physical downlink control channel

PPI power preference identification

PLL phase locked loop

PUCCH physical uplink control channel

RA random access

RACH random access channel

RAN radio access network

RAN2 RAN Working Group 2

RAN4 RAN Working Group 4

RAT radio access technology

RRC radio resource control

RSRP reference signal received power

RSRQ reference signal received quality

RACH random access channel

sec secondary component carrier

Scell or SCell secondary cell

SR scheduling request

TA timing advance

TP throughput

TTI transmission time interval

TTT time-to-trigger

UE user equipment

UL uplink (from UE to base station)

UTRAN universal terrestrial radio access network

VCO voltage controlled oscillator

[0004] In Carrier Aggregation (CA) multiple uplink (UL) or downlink (DL) LTE carriers in contiguous or non-contiguous frequency bands can be bundled. Each aggregated carrier is referred to as a component carrier, CC. The component carrier can have a bandwidth of 1.4, 3, 5, 10, 15 or 20 MHz and a maximum of five component carriers can be aggregated, hence the maximum aggregated bandwidth is 100 MHz. When carrier aggregation is used, there are a number of serving cells, one for each component carrier. The coverage of the serving cells may differ. The RRC connection is only handled by one cell, the primary serving cell (PCell), served by the primary component carrier (PCC, e.g., DL and UL PCCs). In idle mode, the UE listens to system information on the DL PCC. On the UL PCC, PUCCH is sent. The other component carriers are all referred to as secondary component carriers (DL and UL SCCs), serving the secondary serving cells (SCells). The SCCs are added and removed as required, while the PCC is only changed at handover.

[0005] By mean of cross carrier scheduling, users can be dynamically scheduled on the different component carriers. This means a UE might receive a physical downlink control channel (PDCCH) control channel on one carrier with a resource allocation for another carrier. For this, a new information element was added to the downlink control information that is called Carrier Indicator Field (CIF). Release 11 CA also supports inter -band Carrier Aggregation where the component carriers are located in different frequency bands. This should prove to be very beneficial for operators having LTE frequencies in different bands. LTE in general supports a synchronized uplink by means of the uplink Timing Advance (TA) procedure.

[0006] 3GPP TS 36.331 vl l.3.0 (2013-03) and 3GPP TS 36.133 VI 1.4.0 (2013-03) describe various 3GPP specifications. In R4-131235, "Considerations for single-chip implementation of carrier aggregation" Qualcomm Incorporated from 3GPP TSG-RAN WG4 Meeting #66 Bis, Chicago, U.S. A, 15th April - 19th April, 2013, it is discussed how the initial chipset implementations for inter- band and non-contiguous intra-band carrier aggregation most likely will be based on separate integrated circuit chips for each radio chain. The paper also raises the potential of creating solutions based on single-chip, which may have the opportunity to reduce some key parameters such as cost, area and power consumption. However, the tighter integration also comes with some problems, which are discussed in:

• R4-100799, "Need for Measurement gaps with carrier aggregation" Nokia, Nokia Siemens Networks, 3GPP TSG-RAN WG4 Meeting #54, San Francisco, USA, 22nd - 26th February, 2010;

• R4-131231 "Interruptions for intra-band non-contiguous CA", Qualcomm Incorporated, 3GPP TSG-RAN WG4 Meeting #66 Bis, Chicago, U.S.A, 15th April - 19th April, 2013; and

• R4-131664 "Considerations on inter-band carrier aggregation interruptions" Renesas Mobile Europe Ltd., 3 GPP TSG-RAN WG4 Meeting #66bis, Chicago, United States of America, 15 -19 April, 2013.

[0007] Earlier, in connection with intra-band contiguous CA, it was discussed that the interrupt (or glitch) was necessary due to RF re-tuning. Now in R4-131235, R4-131231, and R4- 131664, it is discussed that an interrupt is needed in some implementations also for inter-band CA and intra-band non-contiguous cases. In these cases the interrupt is estimated to be at maximum 2ms (while for a re-tuning case 5ms interrupt was necessary).

[0008] In context of inter-frequency measurements, it has been typically assumed that UEs require measurement gaps to perform inter-frequency measurements, so that if a network configures a UE with inter-frequency measurements, the network needs also to configure the UE with measurements gaps, during which the UE is allowed to stop listening to the serving cell (or PCell) and tune its receiver to another frequency to perform the measurements. UEs that are capable of performing inter-frequency measurements as per the requirements given in 36.133 without measurement gaps can inform the network about this capability in 'UE-EUTRA-Capability' information element as described in 36.331. This removes the need from network to configure the measurements gaps when inter- frequency measurements are configured. This kind of behavior can be supported, for example, by a UE that has multiple different receiver chains that can be independently configured to different frequency bands and from which signal can be received simultaneously. An inter-band CA capable UE can be considered as an example of such UE.

SUMMARY

[0009] This section contains examples of possible implementations and is not meant to be limiting.

[0010] In an exemplary embodiment, a method comprises: determining whether an apparatus can perform measurements without causing interrupts on an active cell; and in response to the determining making a determination that the apparatus cannot perform inter-frequency measurements without causing interrupts on the active cell, preventing the apparatus from indicating that the apparatus can perform measurements without gap assistance.

[0011] An exemplary apparatus includes one or more processors and one or more memories including computer program code. The one or more memories and the computer program code are configured to, with the one or more processors, cause the apparatus to perform at least the following: determining whether an apparatus can perform measurements without causing interrupts on an active cell; and in response to the determining making a determination that the apparatus cannot perform inter-frequency measurements without causing interrupts on the active cell, preventing the apparatus from indicating that the apparatus can perform measurements without gap assistance.

[0012] An additional exemplary embodiment includes a computer program, comprising code for determining whether an apparatus can perform measurements without causing interrupts on an active cell; and in response to the determining making a determination that the apparatus cannot perform inter-frequency measurements without causing interrupts on the active cell, preventing the apparatus from indicating that the apparatus can perform measurements without gap assistance; when the computer program is run on a processor. The computer program according to this paragraph, wherein the computer program is a computer program product comprising a computer-readable medium bearing computer program code embodied therein for use with a computer.

[0013] An exemplary computer program product includes a computer-readable storage medium bearing computer program code embodied therein for use with a computer. The computer program code includes: code for determining whether an apparatus can perform measurements without causing interrupts on an active cell; and code for, in response to the determining making a determination that the apparatus cannot perform inter-frequency measurements without causing interrupts on the active cell, preventing the apparatus from indicating that the apparatus can perform measurements without gap assistance.

[0014] A further exemplary embodiment is an apparatus comprising: means for determining whether an apparatus can perform measurements without causing interrupts on an active cell; and means, responsive to the determining making a determination that the apparatus cannot perform inter- frequency measurements without causing interrupts on the active cell, for preventing the apparatus from indicating that the apparatus can perform measurements without gap assistance.

[0015] In another exemplary embodiment, a method comprises: determining at a base station whether an indication that a user equipment can perform measurements without gaps or interrupts has been received; and in response to a determination the indication that the user equipment can perform measurements without gaps or interrupts has not been received, determining at the base station a gap pattern for the user equipment and sending from the base station an indication of the gap pattern to the user equipment, wherein the gap pattern indicates to the user equipment a schedule under which the user equipment is to the perform measurements.

[0016] An exemplary apparatus includes one or more processors and one or more memories including computer program code. The one or more memories and the computer program code are configured to, with the one or more processors, cause the apparatus to perform at least the following: determining at a base station whether an indication that a user equipment can perform measurements without gaps or interrupts has been received; and in response to a determination the indication that the user equipment can perform measurements without gaps or interrupts has not been received, determining at the base station a gap pattern for the user equipment and sending from the base station an indication of the gap pattern to the user equipment, wherein the gap pattern indicates to the user equipment a schedule under which the user equipment is to the perform measurements.

[0017] An additional exemplary embodiment includes a computer program, comprising code for: determining at a base station whether an indication that a user equipment can perform measurements without gaps or interrupts has been received; and in response to a determination the indication that the user equipment can perform measurements without gaps or interrupts has not been received, determining at the base station a gap pattern for the user equipment and sending from the base station an indication of the gap pattern to the user equipment, wherein the gap pattern indicates to the user equipment a schedule under which the user equipment is to the perform measurements; when the computer program is run on a processor. The computer program according to this paragraph, wherein the computer program is a computer program product comprising a computer- readable medium bearing computer program code embodied therein for use with a computer.

[0018] An exemplary computer program product includes a computer-readable storage medium bearing computer program code embodied therein for use with a computer. The computer program code includes: code for determining at a base station whether an indication that a user equipment can perform measurements without gaps or interrupts has been received; and code for, in response to a determination the indication that the user equipment can perform measurements without gaps or interrupts has not been received, determining at the base station a gap pattern for the user equipment and sending from the base station an indication of the gap pattern to the user equipment, wherein the gap pattern indicates to the user equipment a schedule under which the user equipment is to the perform measurements.

[0019] An additional exemplary embodiment is an apparatus, comprising: means for determining at a base station whether an indication that a user equipment can perform measurements without gaps or interrupts has been received; and means, responsive to a determination the indication that the user equipment can perform measurements without gaps or interrupts has not been received, for determining at the base station a gap pattern for the user equipment and sending from the base station an indication of the gap pattern to the user equipment, wherein the gap pattern indicates to the user equipment a schedule under which the user equipment is to the perform measurements.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In the attached Drawing Figures:

[0021] FIG. 1 is a diagram of a system incorporating features of an example embodiment;

[0022] FIG. 2 illustrates a simplified block diagram of various electronic devices and apparatus that are suitable for use in practicing the exemplary embodiments of this invention;

[0023] FIG. 3 is performed by a user equipment for preventing interrupts on active cell operation and is a block diagram of an exemplary logic flow diagram that illustrates the operation of an exemplary method, a result of execution of computer program instructions embodied on a computer readable memory, and/or functions performed by logic implemented in hardware, in accordance with exemplary embodiments herein; and

[0024] FIG. 4 is performed by a base station for preventing interrupts on active cell operation and is a block diagram of an exemplary logic flow diagram that illustrates the operation of an exemplary method, a result of execution of computer program instructions embodied on a computer readable memory, and/or functions performed by logic implemented in hardware, in accordance with exemplary embodiments herein.

DETAILED DESCRIPTION OF THE DRAWINGS

[0025] Referring to FIG. 1 , there is shown a diagram of a system 1 incorporating features of an example embodiment. Although the features will be described with reference to the example embodiment shown in the drawings, it should be understood that features can be embodied in many alternate forms of embodiments. [0026] The system 1 comprises at least one user equipment (UE) 10 which is able to connect to a primary cell (PCell) 110 (formed by a first base station 14-1 using antenna(s) 100-1, shown in FIG. 2 as eNodeB 14) and a secondary cell (SCell) 120 (formed by a second base station 14-2 using antenna(s) 100-2). It is common to refer to a cell as being an entity communicating with a UE 10, although technically a "cell" is an area formed at least in part by a base station. Referring also to FIG. 2, for illustrating a simplified block diagram of various electronic devices and apparatus that are suitable for use in practicing the exemplary embodiments of this invention. In FIG. 2, a wireless network 1 is adapted for communication over a wireless link 11 with apparatus, such as a mobile communication device which may be referred to as a UE 10, via a network access node, such as an eNodeB 14 for the case of an LTE or LTE-A network. Each of the UEs 10 (only one illustrated at FIGS. 1 and 2 for the sake of simplicity) communicates using a wireless link 11 with the eNodeB 14. The wireless network 1 may include a network control element (NCE) 16 that may implement mobility management entity (MME) and/or serving gateway (S-GW) functionality such as that known in the LTE system, and which provides connectivity with a further network, such as a publicly switched telephone network and/or a data communications network (e.g., the Internet).

[0027] The UE 10 includes a controller, such as a computer or a data processor (DP) 10A, a computer-readable memory (MEM) 10B that tangibly stores a program of computer instructions (PROG) IOC, and at least one suitable radio frequency (RF) transmitter and receiver (shown together as 10D) for bidirectional wireless communications with the eNodeB 14 via one or more antennas 10E (one shown). The UE 10 may also have functionality to demodulate the control channel or distributed control channel/PDCCH or E-PDCCH that it receives over the wireless link 11.

[0028] The eNodeB 14 also includes a controller, such as a computer or a data processor (DP) 14A, a computer-readable memory (MEM) 14B that tangibly stores a program of computer instructions (PROG) 14C, and at least one suitable RF transmitter and receiver (shown together as 14D) for communication with the UE 10 via one or more antennas 14E (two shown, but as with the above examples there may also be four or even an antenna array of more than four). The eNodeB 14 is additionally coupled via a data/control path 13 to the NCE 16. The NCE 16 also includes a controller, such as a computer or a data processor (DP) 16A and a computer-readable memory (MEM) 16B that stores a program of computer instructions (PROG) 16C. The NCE 16 may be connected to additional networks such as the Internet. The path 13 may be implemented as the SI interface known for the LTE system. The eNodeB 14 may also be coupled to another eNodeB (or Node B) via data/control path 15, which may be implemented as the X2 interface known in the LTE system.

[0029] The techniques herein may be considered as being implemented solely as computer program code embodied in a memory resident within the UE 10 or eNodeB 14 (e.g., as PROG IOC or 14C, respectively), or as a combination of embodied computer program code (executed by one or more processors) and various hardware, including memory locations, data processors, buffers, interfaces and the like, or entirely in hardware (such as in a very large scale integrated circuit).

Additionally, the transmitters and receivers 10D and 14D may also be implemented using any type of wireless communications interface suitable to the local technical environment, for example, they may be implemented using individual transmitters, receivers, transceivers or a combination of such components.

[0030] In general, the various embodiments of the UE 10 can include, but are not limited to, cellular telephones, personal digital assistants (PDAs) having wireless communication capabilities, portable computers having wireless communication capabilities, image capture devices such as digital cameras having wireless communication capabilities, gaming devices having wireless communication capabilities, music storage and playback appliances having wireless communication capabilities, Internet appliances permitting wireless Internet access and browsing, as well as portable units or terminals that incorporate combinations of such functions.

[0031] The computer readable MEMs 10B and 14B may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The DPs 10A and 14A may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on a multi-core processor architecture, as non-limiting examples.

[0032] Above, there is mention of how the initial chipset implementations for inter-band and non-contiguous intra-band carrier aggregation most likely will be based on separate integrated circuit chips for each radio chain. There is mention of the potential of creating solutions based on a single chip, which may have the opportunity to reduce some key parameters such as cost, area and power consumption. However, the tighter integration also comes with some problems as described above. In a general example, for a CA-capable UE, there are generally multiple transceivers 10D. In FIG. 2, this is illustrated via two exemplary transceivers lOD-1 and 10D-2. Transceiver lOD-1 comprises a transmitter lOF-1 and receiver lOG-1. Transceiver 10D-2 comprises a transmitter 10F-2 and receiver 10G-2. The transceiver lOD-1 may be on one semiconductor chip lOH-1, and the transceiver 10D-2 may be on another semiconductor chip 10H-2. Furthermore, both transceivers lOD-1 and 10D-2 may be on the same semiconductor chip 10H-3.

[0033] An exemplary case under discussion is caused by a certain UE implementation solution used for implementing CA and likely also future dual connectivity (DC) UEs. A problem is when the UE initiates second receiver activity (such as using receiver 10G-2) while the first receiver lOG-1 is active. This second receiver 10G-2 activity start causes interference on the already active first receiver lOG-1. This interference is also referred to as an interrupt, as described below. The same is likely happening when or if the second receiver 10G-2 is no longer used (e.g., turned off again). This change in second receiver 10G-2 activity can be caused, e.g., by performing measurements using the second receiver 10G-2. That is, the change can be caused by the UE 10, e.g., performing inter-frequency measurements using the second receiver 10G-2 or the change can be caused by UE performing measurements on a configured but deactivated SCell, e.g., according to ScellMeasCycle or measCycleSCell. The change can also happen, e.g., due to

configuration/deconfiguration and activation/deactivation of the SCell and other reasons.

[0034] Interference or interrupt on PCell means that the reception and likely also the transmission on the active receiver chain (the first receiver lOG-1, which is assigned to PCell in this example) is interrupted for given period of time due to the change in the state of the second receiver 10G-2, as described above. This interrupt means that the UE 110 is not able to receive or transmit during the interrupt period (or at least reception/transmission is corrupted due to interference/interrupt for a part of the TTI). The interrupt period is currently understood to be short but means that the UE will not be able to receive the TTI/PDCCH during that time (in that TTI) and the UE 110 cannot transmit in UL in that TTI either (or at least in part of the TTI that results in corrupting the reception/transmission in that TTI). That is, an interrupt is a drop of a DL reception and an UL transmission between UE and network.

[0035] Based on the papers in R4-131235 and R4-131664, it is believed that there is a need to define PCell interrupts at least in the following situations:

• Configuration of SCell;

• De-configuration of SCell;

• Activation of SCell;

• De-activation of SCell;

• Measurement on SCell; and/or

• Inter-frequency Measurement, such as when a UE performs normal inter- frequency measurements on a carrier before a potential cell on that carrier is configured as SCell.

[0036] Interrupts on transmissions to or reception from a PCell at a UE 110 due to activation and de-activation of SCell, as well as interrupts on transmissions to or reception from a PCell at the UE due to measurements on a de-activated SCell have been highlighted and discussed earlier in connection with intra-band contiguous CA and now also for inter-band CA (including also inter- frequency measurements). There is a potential to have significant power saving gains on the UE side by allowing the UE to power down circuits needed for the de- activated SCell when the SCell activity was not needed.

[0037] However, introducing interrupts has certain side effects. If allowing an x ms interrupt, the UL interrupt will in fact be (X+x) ms: X ms from when the interrupt happens and additionally x ms due to lost UL scheduling opportunities from the x ms interrupt. Additionally, the DL ack/nak will be impacted, as the DL ack/nak will be lost in the x ms interrupt period. [0038] It was earlier assumed that CA capable UEs will be able to perform inter-frequency (IF) measurements without measurement gaps (see R4- 100799) for the supported CA combinations. However, as noted above, it has been discovered that this is no longer a valid assumption. A feature as described herein is to define a clear rule for a UE which cannot perform inter-frequency (IF) measurements without causing any disturbance to PCell activity (e.g., interrupts on PCell operation).

[0039] A feature as described herein is that, for a UE which cannot perform inter-frequency measurements without causing interrupts on active cells (e.g., PCell), the UE is not allowed to indicate that the UE can perform inter-frequency measurements without measurement gaps. A measurement gap has a particular length, e.g., of 6ms (e.g., long enough for UE to perform re-tuning and perform physical measurements on another carrier or carriers), while an interrupt is currently understood to be about 1ms (and is caused by, e.g., a second receiver 10G-2 state change). The measurement gaps, for example, may be existing gap patterns as defined, or a new gap pattern, or a gap type.

[0040] In 3GPP TS 36.133, there are two different gap patterns defined. A gap pattern consists of a measurement gap (6ms), where the UE tunes its receiver to another carrier to perform measurements, repeated with a periodicity which is either 40ms or 80ms for these two patterns. This is configured by the network, e.g., via the eNodeB 14. See, e.g., 3GPP TS 36.133 VI 1.4.0 (2013-03) section 8.1.2.1, which states the following:

"Inter-frequency and inter-RAT measurement requirements within this clause rely on the UE being configured with one measurement gap pattern unless the UE has signaled that it is capable of conducting such measurements without gaps. UEs shall only support those measurement gap patterns listed in Table 8.1.2.1-1 that are relevant to its measurement capabilities."

[0041] Furthermore, Table 8.1.2.1-1, "Gap Pattern Configurations supported by the UE", states the following:

Gap MeasurementGap Measurement Minimum available Measurement Pattern Length (MGL, Gap time for inter- Purpose

Id ms) Repetition frequency and inter-

Period RAT measurements

(MGRP, ms) during 480ms

period

(Tinterl,

ms)

0 6 40 60 Inter-Frequency E- UTRAN FDD and TDD, UTRAN FDD, GERAN, LCR TDD, HRPD, CDMA2000 lx

1 6 80 30 Inter-Frequency E- UTRAN FDD and TDD, UTRAN FDD, GERAN, LCR TDD, HRPD, CDMA2000 lx

[0042] By not allowing the UE to indicate that the UE can perform inter-frequency measurements without measurement gaps, the network will recognize the UE cannot or should not perform inter-frequency measurement without gaps and the network may assign measurement gaps (a measurement gap pattern) to the UE. If the UE indicates that the UE does need measurement gaps for inter-frequency measurements, the network needs to assign a gap pattern to the UE and activate the gap pattern before the UE is required to perform inter-frequency measurements.

[0043] Features may be realized in RAN2 and/or RAN4 specification, for example, by stating an additional condition that, if a start of SCell activity or activity on that carrier frequency (e.g., inter-frequency measurements) causes interruptions, the UE is not allowed to indicate that the UE can perform inter-frequency measurements without network assisted measurement gaps. The SCell activity may be in the form of cell detection and/or measurements for example. Rather than SCell, or in addition to SCell, this may be applied to any inter-frequency carrier and /or inter- frequency neighbor cell.

[0044] In addition, a feature as described herein is that the UE would not indicate to the network that the UE has the capability of performing inter-frequency measurement without gaps (and would therefore need gap assistance, e.g., according to 36.331 and 36.133 or any other gap assistance).

[0045] Another option would be that, in case such a UE indicates the UE interrupts, the UE would then implicitly also indicate that the UE needs gap assistance for inter-frequency

measurements. The gap assistance may be in form of either existing gap patterns or new gap patterns or gap occurrences (e.g., single gaps). [0046] An additional option is that a separate capability could be defined for UEs that can perform inter-frequency measurements without gaps, but that some level of interruptions to PCell reception would be allowed.

[0047] Technical effects include but are not limited to:

• Solves the present problem of an unclarified specification;

• Uses existing method to enable solution;

• Ensures network operation;

• Allows UE implementation freedom; and/or

• Enables UE power saving for integrated CA modems.

[0048] Features may be used with CA capable UEs which have an integrated CA solution (a single circuit chip for CA for example).

[0049] An example embodiment of an apparatus may comprise at least one processor; at least one memory comprising software, where the at least one processor, the at least one memory, and the software are configured to: prevent the apparatus from indicating that the apparatus can perform inter-frequency measurements without gaps when the apparatus cannot perform inter-frequency measurements without causing interrupts on an active cell.

[0050] An example embodiment of an apparatus may comprise at least one processor; at least one memory comprising software, where the at least one processor, the at least one memory, and the software are configured to: if a start of SCell activity by the apparatus causes interruptions, preventing the apparatus from indicating that the apparatus can perform inter-frequency measurements without network assisted measurement gaps.

[0051] An example embodiment of an apparatus may comprise: at least one processor; at least one memory comprising software, where the at least one processor, the at least one memory, and the software are configured to: not indicate to a network that the apparatus has a capability of performing inter-frequency measurement without gaps.

[0052] An example embodiment of an apparatus may comprise: at least one processor; at least one memory comprising software, where the at least one processor, the at least one memory, and the software are configured to: indicating that the apparatus cannot perform inter-frequency measurements without causing interrupts on an active cell, and only by the indicating that the apparatus cannot perform inter-frequency measurements without causing interrupts on an active cell, implicitly indicate that the apparatus needs gap assistance for inter-frequency measurements.

[0053] Referring also to FIG. 3, an example method may comprise determining whether an apparatus can perform inter-frequency measurements (e.g., of a secondary cell) without causing interrupts on an active cell (e.g., a primary cell) as indicated by block 20; and in response to the determining indicating that the apparatus cannot perform (e.g., inter-frequency) measurements without causing interrupts on an active cell, preventing the apparatus from indicating to the network that the apparatus can perform (e.g., inter-frequency) measurements without gap assistance as indicated by block 22. Examples of preventing the apparatus from indicating to the network that the apparatus can perform measurements without gap assistance may include preventing the apparatus from indicating to the network that the apparatus can perform measurements without measurement gaps or without interrupts. Note that the interrupts are interrupts in UL transmission (e.g., on transmitter lOF-1) or DL reception (e.g., on receiver lOG-1) based on reception by receiver 10G-2. How the UE determines when the apparatus cannot perform inter-frequency measurements without causing interrupts may be basically a UE specific design issue (see block 24) and may depend on what the CA combination is and also how the spurious transmissions from the VCO are. In addition, the determination can also come from power pulling, in the sense that when the new activity is initiated, the new activity may lead to a change in drain on the PLL/VCO which may then affect the phase which takes some time to settle. Note that the measurements are typically inter-frequency measurements of SCells, but are not limited to these and may, e.g., but inter-frequency measurements of carriers or possibly intra-frequency measurements.

[0054] Examples of block 22 are illustrated by blocks 26 and 28. In block 26, if a start of a cell activity (e.g., by transmitter 10F-2/receiver 10G-2 for SCell or another cell different from the active cell) by the apparatus causes interruptions on the active cell (e.g., on transmitter lOF-l/receiver lOG-lfor PCell), the apparatus performs preventing the apparatus from indicating that the apparatus can perform inter-frequency measurements without network assisted measurement gaps. Note that the measurement gaps can include existing defined measurement gaps, but are not limited thereto and may be newly defined measurement gaps. In block 28, the apparatus performs the operation of not indicating to the network that the apparatus has a capability of performing inter-frequency measurement without measurement gaps

[0055] In block 30, the apparatus optionally performs indicating to a network that the apparatus cannot perform (e.g., inter-frequency) measurements without causing interrupts on an active cell. An example of block 30 is illustrated by block 32, where, by the indicating that the apparatus cannot perform inter-frequency measurements without causing interrupts on an active cell, implicitly indicate that the apparatus needs gap assistance (e.g., existing gap patterns or newly defined gap patterns) for inter-frequency measurements. That is, if the apparatus indicates to a base station that the apparatus cannot perform inter-frequency measurements without causing interrupts on an active cell, this indication implies to the base station that the apparatus needs gap assistance for inter- frequency measurements.

[0056] Block 34, where the apparatus performs receiving indication of a gap pattern from base station, may be performed in multiple locations as shown. For instance, the base station may, upon determining there is no indication the apparatus can perform inter-frequency measurements without gaps, send the indication of a gap pattern prior to block 30. As another example, after the base station receives the indication responsive to block 30, the base station would send and the apparatus would receive in block 34 the indication of gap pattern.

[0057] In block 36, the apparatus performs using the gap pattern to perform (e.g., inter- frequency) measurements on secondary cell(s). In block 38, the apparatus performs reporting the (e.g., inter-frequency) measurements on the secondary cell(s) to the active cell (e.g., the base station forming the active cell). It is noted that the reporting may not be to the active cells and could be to other entities in the network, such as to the secondary cells.

[0058] Turning to FIG. 4, this figure is performed by a base station (e.g., eNodeB 14) for preventing interrupts on active cell operation. This figure is also a block diagram of an exemplary logic flow diagram that illustrates the operation of an exemplary method, a result of execution of computer program instructions embodied on a computer readable memory, and/or functions performed by logic implemented in hardware, in accordance with exemplary embodiments herein.

[0059] In block 52, the base station performs determining whether an indication that a UE can perform inter-frequency measurements without gaps has been received. If an indication that the UE can perform inter-frequency measurements without gaps has been received (block 54 = Yes), in block 56, the base station performs the operation of performing operations for a UE that can perform inter-frequency measurements without gaps.

[0060] On the other hand, if there is no indication received that the UE can perform inter- frequency measurements without gaps (block 54 = NO), in block 58, the base station performs the operation of determining whether to schedule measurement gaps for the UE. Which gap pattern (if any) to use can depend on many things. Also, the gap pattern may not always be configured and/or active. For instance, if the UE is not at a cell edge, there might not be a need to have the measurements active on the UE side. If the base station determines there should be measurement gaps scheduled for the UE (block 60 = Yes), in block 62, the base station performs determining a gap pattern for the UE, and in block 64, the base station performs the operation of sending an indication of a gap pattern to UE. Note that there could be multiples indications sent. In block 66, the base station performs activating the gap pattern, e.g., through RRC signaling. It is noted that blocks 64 and 66 could be combined and need not be independent operations. The flow proceeds to block 76, which is described below.

[0061] Block 68 may be reached if the base station determines not to schedule gaps for the UE (block 60 = No). It is further noted that block 68 can be optional. In block 68, the base station performs the operation of determining whether an indication is received that the UE cannot perform inter-frequency measurements without causing interrupts on an active cell. If the indication is received (block 70 = Yes), the base station then performs (block 72) implying that the apparatus needs gap assistance. That is, the receipt of the indication that the UE cannot perform inter-frequency measurements without causing interrupts on an active cell implies that the UE needs gap assistance. Therefore, the base station performs (block 74) blocks 62, 64, and 66 to determine a gap pattern for the UE, send the gap pattern to the UE and activate the gap pattern. It is noted that activating the gap pattern (in block 62) is an optional step. The flow proceeds to block 76, where the base station performs receiving inter-frequency measurements on secondary cell(s) from the UE. Block 76 may be reached also from block 66. It is noted that block 76 is optional, e.g., as receiving the measurements is not guaranteed and only something that may happen. If the indication is not received (block 70 = Yes), the flow ends in block 78.

[0062] For any blocks described above that determine any 'gap pattern', the determined gap pattern is not limited to existing patterns in current specifications. Instead (or in addition to existing patterns), the options listed earlier in the description are also possible and the gap pattern could even be a new, previously unused gap pattern.

[0063] The following are examples. Example 1. A method comprising: determining whether an apparatus can perform measurements without causing interrupts on an active cell; and in response to the determining making a determination that the apparatus cannot perform inter-frequency measurements without causing interrupts on the active cell, preventing the apparatus from indicating that the apparatus can perform measurements without gap assistance. Example 2. The method of example 1, wherein preventing further comprises, if a start of a cell activity by the apparatus causes interruptions on the active cell, where the cell activity is for a cell different from the active cell, preventing the apparatus from indicating that the apparatus can perform measurements without network-assisted measurement gaps. Example 3. The method of example 1, wherein preventing further comprises not indicating to a network that the apparatus has a capability of performing measurement without measurement gaps.

[0064] Example 4. The method of any of examples 1 to 3, wherein the method further comprises indicating to a network that the apparatus cannot perform measurements without causing interrupts on an active cell, whereby by the indicating that the apparatus cannot perform

measurements without causing interrupts on an active cell, this implicitly indicates that the apparatus needs gap assistance for measurements. Example 5. The method of any of examples 1 to 4, further comprising: receiving an indication of a gap pattern; using the gap pattern to perform measurements on a secondary cell; and reporting indications of the measurements.

[0065] Example 6. The method of any of examples 1 to 5, wherein the active cell is a primary cell used for carrier aggregation and the measurements are to be or are performed on a secondary cell used for the carrier aggregation. Example 7. The method of example 6, wherein the interrupts are interrupts of at least one of uplink or downlink communications between the apparatus and the active cell and the interrupts are caused by a receiver performing the measurements of the secondary cell. Example 8. The method of any of examples 1 to 7, wherein the measurements are inter-frequency measurements. [0066] Example 9. An apparatus comprising: means for determining whether an apparatus can perform measurements without causing interrupts on an active cell; and means, responsive to the determining making a determination that the apparatus cannot perform inter-frequency measurements without causing interrupts on the active cell, for preventing the apparatus from indicating that the apparatus can perform measurements without gap assistance.

[0067] Example 10. The apparatus of example 9, wherein the means for preventing further comprises means, if a start of a cell activity by the apparatus causes interruptions on the active cell, where the cell activity is for a cell different from the active cell, for preventing the apparatus from indicating that the apparatus can perform measurements without network-assisted measurement gaps. Example 11. The apparatus of example 9, wherein the means for preventing further comprises means for not indicating to a network that the apparatus has a capability of performing measurement without measurement gaps.

[0068] Example 12. The apparatus of any of examples 9 to 11, further comprising means for indicating to a network that the apparatus cannot perform measurements without causing interrupts on an active cell, whereby by the indicating that the apparatus cannot perform measurements without causing interrupts on an active cell, this implicitly indicates that the apparatus needs gap assistance for measurements. Example 13. The apparatus of any of examples 9 to 12, further comprising: means for receiving an indication of a gap pattern; means for using the gap pattern to perform measurements on a secondary cell; and means for reporting indications of the measurements.

[0069] Example 14. The apparatus of any of examples 9 to 13, wherein the active cell is a primary cell used for carrier aggregation and the measurements are to be or are performed on a secondary cell used for the carrier aggregation. Example 15. The apparatus of example 14, wherein the interrupts are interrupts of at least one of uplink or downlink communications between the apparatus and the active cell and the interrupts are caused by a receiver performing the measurements of the secondary cell. Example 16. The apparatus of any of examples 9 to 15, wherein the measurements are inter-frequency measurements.

[0070] Example 17. A user equipment comprising the apparatus of any of examples 9 to 16.

[0071] Example 18. A method, comprising: determining at a base station whether an indication that a user equipment can perform measurements without gaps or interrupts has been received; and in response to a determination the indication that the user equipment can perform measurements without gaps or interrupts has not been received, determining at the base station a gap pattern for the user equipment and sending from the base station an indication of the gap pattern to the user equipment, wherein the gap pattern indicates to the user equipment a schedule under which the user equipment is to the perform measurements.

[0072] Example 19. The method of example 18, further comprising activating the gap pattern. Example 20. The method of any of examples 18 or 19, wherein determining a gap pattern for the user equipment is performed further in response to not receiving the indication. Example 21. The method of any of examples 18 to 20, further comprising receiving measurements from the user equipment. Example 22. The method of any of examples 18 to 21, wherein the base station forms an active cell, the active cell is a primary cell used for carrier aggregation by the user equipment, and the measurements were performed by the user equipment on a secondary cell used for the carrier aggregation.

[0073] Example 23. The method of example 22, wherein the interrupts are interrupts at the user equipment of at least one of uplink or downlink communications between the user equipment and the active cell and the interrupts are caused by a receiver at the user equipment performing the measurements of the secondary cell. Example 24. The method of any of examples 18 to 23, wherein the measurements are inter-frequency measurements.

[0074] Example 25. An apparatus, comprising: means for determining at a base station whether an indication that a user equipment can perform measurements without gaps or interrupts has been received; and means, responsive to a determination the indication that the user equipment can perform measurements without gaps or interrupts has not been received, for determining at the base station a gap pattern for the user equipment and sending from the base station an indication of the gap pattern to the user equipment, wherein the gap pattern indicates to the user equipment a schedule under which the user equipment is to the perform measurements.

[0075] Example 26. The apparatus of example 25, further comprising means for activating the gap pattern. Example 27. The apparatus of any of examples 25 or 26, wherein the determining a gap pattern for the user equipment is performed further in response to not receiving the indication. Example 28. The apparatus of any of examples 25 to 27, further comprising means for receiving measurements from the user equipment.

[0076] Example 29. The apparatus of any of examples 25 to 28, wherein the base station forms an active cell, the active cell is a primary cell used for carrier aggregation by the user equipment, and the measurements were performed by the user equipment on a secondary cell used for the carrier aggregation. Example 30. The apparatus of example 29, wherein the interrupts are interrupts at the user equipment of at least one of uplink or downlink communications between the user equipment and the active cell and the interrupts are caused by a receiver at the user equipment performing the measurements of the secondary cell. Example 31. The apparatus of any of examples 25 to 30, wherein the measurements are inter-frequency measurements.

[0077] Example 32. A base station comprising the apparatus of any of examples 25 to 31. Example 33. A system comprising an apparatus of any of examples 9 to 16 and an apparatus of any of examples 25 to 31.

[0078] Example 34. A computer program comprising program code for executing the apparatus according to any of examples 1 to 8 or 18 to 24. Example 35. The computer program according to example 34, wherein the computer program is a computer program product comprising a computer-readable medium bearing computer program code embodied therein for use with a computer.

[0079] Example 36. An apparatus comprises one or more processors and one or more memories including computer program code. The one or more memories and the computer program code are configured to, with the one or more processors, cause the apparatus to perform the method according to any of examples 1 to 8 or 18 to 24.

[0080] It should be understood that the foregoing description is only illustrative. Various alternatives and modifications can be devised by those skilled in the art. For example, features recited in the various dependent claims could be combined with each other in any suitable combination(s). In addition, features from different embodiments described above could be selectively combined into a new embodiment. Accordingly, the description is intended to embrace all such alternatives, modifications and variances which fall within the scope of the appended claims. It should be further noted that the blocks in FIGS. 3 and 4 may be considered to be interconnected means for performing the functions in the blocks.

[0081] Embodiments of the present invention may be implemented in software (executed by one or more processors), hardware (e.g., an application specific integrated circuit), or a combination of software and hardware. In an example embodiment, the software (e.g., application logic, an instruction set) is maintained on any one of various conventional computer-readable media. In the context of this document, a "computer-readable medium" may be any media or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer, with one example of a computer described and depicted, e.g., in FIG. 2. A computer-readable medium may comprise a computer-readable storage medium (e.g., memory(ies) 10B, 14B or other device) that may be any media or means that can contain or store the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer. A computer readable storage medium does not, however, encompass propagating signals.

[0082] If desired, the different functions discussed herein may be performed in a different order and/or concurrently with each other. Furthermore, if desired, one or more of the above- described functions may be optional or may be combined.

[0083] Although various aspects of the invention are set out in the independent claims, other aspects of the invention comprise other combinations of features from the described embodiments and/or the dependent claims with the features of the independent claims, and not solely the combinations explicitly set out in the claims.