as) United States
`a2) Patent Application Publication co) Pub. No.: US 2011/0267957 Al
` Duet al. (43) Pub. Date: Nov.3, 2011
`
`
`
`US 20110267957A1
`
`(54) DISCONTINUOUS RECEPTION IN CARRIER
`AGGREGATION WIRELESS
`COMMUNICATION SYSTEMS
`
`(76)
`
`Inventors:
`
`Lei Du, Beijing (CN); Min Huang,
`Beijing (CN); Yong Teng, Beijing
`(CN)
`
`(21) Appl. No.:
`
`13/143,464
`
`(22)
`
`PCTFiled:
`
`Jan. 7, 2009
`
`(86) PCT No.:
`
`PCT/EP2009/050134
`
`§ 371 (c)(),
`(2), (4) Date:
`Jul. 6, 2011
`Publication Classification
`
`(51)
`
`Int. Cl.
`HOAW 52/02
`HO4AW 24/00
`HOAW 72/04
`
`(2009.01)
`(2009.01)
`(2009.01)
`
`(52) US. CDeee 370/241; 370/329; 370/311
`
`(57)
`
`ABSTRACT
`
`A communication system is presented, which is capable of
`sending a transmission over an interface having at least two
`aggregated componentcarriers including a primary compo-
`nent carrier and at least one secondary componentcarrier,
`wherein the primary componentcarrier has a physical down-
`link control channel (PDCCH) associated therewith and
`wherein the PDCCHis capable of signaling allocations for
`the primary componentcarrier and the at least one secondary
`componentcarrier. A methodof operating a network element
`including sending to a user equipmenta transmission indica-
`tion indicative of the transmission in the PDCCH of the
`primary component carrier. A method of operating a user
`equipment includes monitoring downlink control signaling
`for a transmission indication indicative of a transmission to
`the user equipment only on the PDCCHofthe primary com-
`ponentcarrier.
`
`
`
`
` K wt
`
`
`1
`
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`

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`Patent Application Publication
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`Nov. 3, 2011 Sheet 1 of 4
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`Patent Application Publication
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`Nov. 3, 2011 Sheet 4 of 4
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`US 2011/0267957 Al
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`

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`US 2011/0267957 Al
`
`Nov. 3, 2011
`
`DISCONTINUOUS RECEPTION IN CARRIER
`AGGREGATION WIRELESS
`COMMUNICATION SYSTEMS
`
`FIELD OF INVENTION
`
`[0001] The present inventionrelates to the field of wireless
`communication and in particular to thefield of carrier aggre-
`gation in wireless communication.
`
`ART BACKGROUND
`
`[0012] According to a first aspect of the herein disclosed
`subject matter there is provided a method of operating a
`network element capable of sending a transmission over an
`interface having at least two aggregated componentcarriers
`including a primary componentcarrier and at least one sec-
`ondary component carrier, the primary component carrier
`having a physical downlink control channel (PDCCH)asso-
`ciated therewith, wherein the PDCCHis capable ofsignaling
`allocations for the primary component carrier andthe at least
`one secondary componentcarrier.
`[0013] Examples of a user equipment(referred to as UE
`hereinafter) include but are not limited to a mobile phone, a
`mobile computer, etc. Examples of a network element include
`butare not limited to a base station of a wireless communi-
`
`Inorderto achieve higher peak data rates, ithas been
`[0002]
`proposed operate in spectrum allocations of different sizes
`including wider spectrum allocations than e.g.
`those of
`Release 8 LTE (LTE=Long Term Evolution), e.g. up to 100
`cations network, e.g. an e-nodeB.
`MHz,e.g. to achieve the peak data rate of 100 Mbit/s for high
`[0014] According to an embodiment, the method according
`mobility and 1 Gbit/s for low mobility. Moreover, backward
`to the first aspect comprises sending to a UE a transmission
`indication indicative ofthe transmission in the PDCCHofthe
`compatibility is desirable.
`[0003] A possible measure for achieving wider spectrum
`primary componentcarrier.
`allocations is carrier aggregation, where two or more compo-
`[0015] According to a further embodiment, an on-duration
`nent carriers are aggregated, as it is considered for LTE-
`timer is configured only on the primary componentcarrier,
`Advanced in order to support downlink transmission band-
`e.g. by respective signaling ofthe network elementto the user
`widths larger than 20 MHz.
`equipment. The on-duration indicating the time duration the
`[0004] Auser equipment (UB), e.g. a terminal, may simul-
`user equipment monitors the PDCCH for allocations.
`taneously receive one or multiple componentcarriers depend-
`According to a further embodimentthe offsets of the on-
`ing on its capabilities:
`duration are configured by radio resource control (RRC)sig-
`[0005] An LTE-Advanced terminal with reception capa-
`naling. Thus the power consumption can be decreased.
`bility beyond 20 MHz can simultaneouslyreceive trans-
`[0016] According to a further embodiment the PDCCH on
`missions on multiple componentcarriers.
`primary component carrier is capable of configuring the
`[0006] AnLTE Rel-8 terminalcan receive transmissions
`transmission in the following subframes, i.e. the subframes
`on a single componentcarrier only, provided that the
`which follow the subframe wherein the PDCCHis transmit-
`structure of the component carrier follows the Rel-8
`ted. The method accordingto the first aspect may be config-
`specifications.
`ured accordingly. For example, according to a further
`[0007]
`FIG. 1 gives an exampleofthe carrier aggregation of
`embodiment, the method according to the first aspect may
`an LTE Advanced System. M Rel8 bandwidth “chunks”, or
`further comprise defining a timing gap between, in the UF,
`componentcarriers 2, indicated with C1, C2, C3, C4 and C5
`successful decoding of the transmission indication andstart-
`over frequency f in FIG. 1, are combined together to form
`ing of an inactivity timer on a secondary componentcarrier,
`MxRel8 Bandwidth 4, e.g. 5x20 MHz=100 MHz, given M=5,
`the inactivity timer indicating the time duration the UE at
`for the system illustrated in FIG.1. In the illustrated example,
`least waits until deactivating reception on the component
`Rel’8 terminals receive/transmit on one componentcarrier,
`carrier associated with the inactivity timer. According to an
`whereas LTE-Advanced terminals may receive/transmit on
`embodiment, defining such a timing gap is performed by
`multiple component carriers simultaneously to reach the
`sending to a UEatiming gap messagefor configuring the UE
`higher bandwidths, e.g. an LTE Advanced maximum band-
`to imposethe timing gap between the successful decoding of
`width 4 of 100 MHz,as shownin FIG.1.
`the transmission indication and the starting of an inactivity
`[0008] On the other hand, besides higher peak data rates,
`timer on a secondary componentcarrier.
`power consumption is an important issue.
`[0017] Herein, a subframe is a basic timing unit of radio
`[0009]
`Inview ofthe above-describedsituation, there exists
`resource, e.g. of radio resource in LTE framestructure. For
`a need for an improved technique that enables carrier aggre-
`example, according to an illustrative embodiment, downlink
`gation, while substantially avoidingor at least reducing one or
`and uplink transmissions are organized into radio frames with
`moreof the above-identified problems.
`a predefined duration, e.g. with 10 ms duration as defined in
`3GPP TS 36.300 V8.6.0 (September 2008). Each radio frame
`is divided into a predefined number of equally sized sub-
`frames. Each subframe may consist of a further predefined
`numberof equally sized slots. For example, according to TS
`36.300 V8.6.0, for frequency division duplexing (FDD), 10
`subframes are available for downlink transmission and 10
`
`SUMMARYOF THE INVENTION
`
`[0010] This need may be metby the subject matter accord-
`ing to the independent claims. Advantageous embodiments
`are described by the dependent claims.
`[0011] Aspects of the herein disclosed subject matter are
`based on the idea to implement a concept of discontinuous
`reception DRX on a system capableofcarrier aggregation. In
`order to reduce power consumption, it is proposed to intro-
`duce to carrier aggregation system a concept ofdiscontinuous
`reception wherein the user equipment and a network element
`negotiate time intervals in which data transfer happens. Out-
`side these timeintervals, the user equipmentturnsits receiver
`off and enters a low powerstate.
`
`subframesare available for uplink transmissions in each 10
`msinterval and each subframe consists of two slots. Uplink
`and downlink transmissions are separated in the frequency
`domain. According to other embodiments, e.g. where the UE
`has a preconfigured timing gap betweenthe successful decod-
`ing of the transmission indication andthe starting of an inac-
`tivity timer on a secondary componentcarrier, no such timing
`gap messageis sent by the network element to the UE.
`
`6
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`

`

`US 2011/0267957 Al
`
`Nov. 3, 2011
`
`[0026] According to a further embodiment, the timing gap
`is defined by a timing gap duration value stored in the user
`equipment.
`[0027] According to a further embodiment, the method
`according to the third aspect comprises (a) receiving on the
`primary componentcarrier a message indicating the prepara-
`tion of signal reception on at least one of the at least one
`secondary componentcarrier; and (b) receiving the transmis-
`sion indication on the primary componentcarrier, e.g. on the
`PHCCHofthe primary componentcarrier.
`[0028] According to a further embodiment, only the pri-
`mary componentcarrier is configured with an on-duration
`timer defining a time duration during which the user equip-
`ment monitors the PDCCHforallocations.
`
`[0018] According to a further embodiment the PDCCH on
`primary componentcarrier is not capable of configuring the
`transmission in the following subframes. For example, the
`PDCCHonthe primary componentcarrier may be capable of
`configuring the transmission only in subframe ofthe PDCCH.
`The method according to the first aspect may be configured
`accordingly. For example, according to a further embodiment
`the method further comprises (a) sending to a UE a reception
`preparation message indicating the requirement of preparing
`at least one secondary componentcarrier for signal reception
`thereon; and (b) sending the transmission indication on the
`primary componentcarrierandstarting the inactivity timer on
`the secondary component carrier. Hence, according to an
`embodiment wherein the PDCCH onthe primary component
`carrier can only configure the transmission in the same sub-
`frame, a two-step signaling from the network elementto the
`user equipmentis executed, i.e. steps (a) and (b) are carried
`out in two sequent subframes.
`[0019] According to a further embodiment, on-duration is
`configured on at least one secondary componentcarrier. The
`on-duration indicating the time duration the user equipment
`monitors the PDCCHforallocations or stays awake for pos-
`sible downlink data transmission. For example, on-duration
`may be configured on every secondary componentcarrier.
`Hence, according to these embodiments, no timing gap
`between PDCCHindication and data transmission is needed.
`
`[0029] According to a still further embodiment, the pri-
`mary componentcarrier and at least one of the at least one
`secondary componentcarrier is configured with an on-dura-
`tion timer. According to an embodiment, the on-duration
`timer defines a time duration during which the user equip-
`ment monitors the PDCCHforallocations or stays awake for
`possible downlink data transmission. According to a further
`embodiment, the range of on-duration on the primary com-
`ponentcarrier coversall on-duration ranges of on-duration on
`the at least one secondary componentcarrier.
`[0030] According to a still further embodiment, the method
`according to the third aspect further comprises starting an
`For example, according to a still further embodi-
`[0020]
`inactivity timer ona secondary componentcarrier only within
`mentofthe first aspect, the method further comprises signal-
`an active time on the secondary componentcarrier, wherein
`ing to the UE offsets ofon-duration ofthe primary component
`the inactivity timer indicates the time duration the UEat least
`carrier and the at least one second componentcarrier.
`waits until deactivating reception on the componentcarrier
`[0021] According to a second aspect ofthe herein disclosed
`associated with the inactivity timer.
`subject matter, a network element is configured for carrying
`
`out the method according to one or more of the embodiments [0031] According toastill further embodiment, the active
`time indicates the time duration which includes on-duration
`of the first aspect.
`and inactivity timer. For example, according to an embodi-
`[0022] According to a third aspect of the herein disclosed
`ment the active time indicates the time duration wherein
`subject matter there is provided a methodof operating a user
`equipment capable of receiving a transmission over an inter-
`face having at least two aggregated componentcarriers of
`which a primary componentcarrier has a physical downlink
`control channel (PDCCH)associated therewith, the PDCCH
`capable of signaling allocations for the primary component
`carrier and at least one secondary componentcarrier.
`[0023] According to an embodimentofthe third aspect, the
`method comprises monitoring downlink controlsignaling for
`a transmission indication indicative of a transmission to the
`user equipment only on the PDCCHofthe primary compo-
`nentcarrier.
`
`either the on-duration timeror the inactivity timeris running.
`[0032] According to a fourth aspect of the herein disclosed
`subject matter, a user equipment (UE) is provided which is
`configured to carry out the method according to the third
`aspect or an embodimentthereof.
`[0033] According to a fifth aspect, a computer program is
`provided which, when being executed by a data processor, is
`adapted for controlling a method according tothefirst aspect
`or an embodimentthereof.
`
`[0034] According to a sixth aspect, a computer program is
`provided which, when being executed by a data processor, is
`adapted for controlling a method accordingto the third aspect
`or an embodimentthereof.
`
`[0024] According to a further embodiment of the third
`aspect, the user equipment is capable of receiving the trans-
`mission on at least one secondary componentcarrier in a
`following subframe which follows a subframe in which the
`transmission indication was sent (subframe of the PDCCH).
`According to a further embodiment, the methodofthe third
`aspect is configured accordingly. For example, according to a
`further embodiment, the method further comprises imposing
`atiming gap between successful decoding ofthe transmission
`indication andstarting of an inactivity timer, the inactivity
`timer indicating the duration that the UE at least waits until
`deactivating reception on the componentcarrier associated
`with the inactivity timer.
`[0025] According to a further embodiment, the timing gap
`is defined by a timing gap message transmitted by a network
`element.
`
`In the following there will be described exemplary
`[0035]
`embodiments of the subject matter disclosed herein with ref-
`erence to a method for operating a user equipment and a
`methodfor operating a network element.It has to be pointed
`out that of course any combination of features relating to
`different aspects of the herein disclosed subject matter is also
`possible. In particular, some embodimentsare described with
`reference to apparatus type claims whereas other embodi-
`ments are described with reference to method type claims.
`However, a person skilledin the art will gather from the above
`and the following description that, unless other notified, in
`addition to any combination of features belonging to one
`aspect also any combination between features relating to
`different aspects or embodiments, for example even between
`
`7
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`

`

`US 2011/0267957 Al
`
`Nov. 3, 2011
`
`features of the apparatus type claims and features of the
`methodtype claims is considered to be disclosed with this
`application.
`[0036]
`Further, a person skilled in the art will gather from
`the above and the following description that, unless other
`notified, in addition to any combination of features belonging
`to one aspect also any combination between featuresrelating
`to different aspects or embodiments,
`for example even
`between features relating to a network element and features
`relating to auser equipment is consideredto be disclosed with
`this application. In particular the skilled person will gather
`from the herein disclosed subject matter that e.g. settings in
`the UE may be configured by respective signaling of the
`network element to the UE. Herein, the wording “starting a
`timer”includes “starting a timerfor the first time” as well as
`“restarting a timer”.
`[0037] The aspects defined above and further aspects are
`apparent from the examples of embodimentto be described
`hereinafter and are explained with reference to the examples
`of embodiment. The herein disclosed subject matter will be
`described in more detail hereinafter with reference to
`
`examples of embodimentgivenin the detailed description but
`to which the herein disclosed subject matteris not limited.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG.1 illustrates carrier aggregation in a long-term
`[0038]
`evolution advanced (LTE-A) system.
`[0039]
`FIG.2 illustrates on-duration and inactivity timer in
`a LIE system.
`[0040]
`FIG. 3 shows three componentcarriers including
`primary componentcarrier having a joint physical downlink
`control channel (PDCCH).
`[0041]
`FIG. 4 shows an exemplary illustration of a proce-
`dure of dynamic DRX design.
`[0042]
`FIG. 5 shows an exemplary illustration of a proce-
`dure of semi-persistent DRX design.
`
`DETAILED DESCRIPTION
`
`[0043] The illustration in the drawings is schematic. It is
`noted that in different figures, similar or identical elements
`are provided with the same reference signs or with reference
`signs, which are different from the corresponding reference
`signs only withinthefirst digit or within an appendixstarting
`with a character.
`
`[0047] On-duration: duration, e.g. in downlink subframes,
`that the UE waits for, after waking up from DRX,to receive
`physical downlink control channels
`(PDCCHs) which
`informs the UE about resourceallocation. Ifthe UE success-
`fully decodes a PDCCH,the UE stays awake andstarts the
`inactivity timer.
`in downlink sub-
`[0048]
`Inactivity-timer: duration, e.g.
`frames, that the UE waits to successfully decode a PDCCH,
`from the last successful decoding of a PDCCH,failing which
`it re-enters DRX. The UEshall restart the inactivity timer
`following a single successful decoding ofa PDCCHfora first
`transmission only (i.e. not for retransmissions).
`[0049] Active-time: total duration that the UE is awake.
`This includes the “on-duration” of the DRX cycle, the time
`UEis performing continuous reception while the inactivity
`timer has not expired and the time UEis performing continu-
`ous reception while waiting for a downlink (DL)retransmis-
`sion after one HARQ RIT (Hybrid Automatic Repeat
`reQuest Round Trip Time). Based on the above the minimum
`active time is of length equal to on-duration, and the maxi-
`mum is undefined (infinite).
`[0050] According to an embodiment, the entities of on-
`duration timer and DRX inactivity timerare given asfollows:
`[0051] On-duration timer: Specifies the number of con-
`secutive PDCCH-subframe(s) at the beginning of a DRX
`Cycle.
`[0052] DRX inactivity timer: Specifies the numberof con-
`secutive PDCCH-subframe(s) after successfully decoding a
`PDCCHindicating an initial uplink (UL) or downlink (DL)
`user data transmission for this UE.
`[0053] These definitions correspond to the definitions in
`3GPP TS 36.321, without being limited to the framework
`thereof.
`
`FIG. 2 exemplarily illustrates a timing diagram over
`[0054]
`time t for an on-durationtimer6, defining an on-duration 8,as
`well as two inactivity timers 10a, 105 defining inactivity time
`durations 12a, 126, respectively. Together the on-duration
`timer 6 and inactivity timers 10a, 105 define the active time
`14. In the timing diagram of FIG.2, the upper level 16 indi-
`cates that the UE shall monitor the PDCCH (awakestate),
`whereas the lower level 18 indicates that the UE shall not
`
`monitor the PDCCH(sleep state). The beginning of the on-
`duration 8, indicated at 20 in FIG.2, is referred to as DRX
`timeout. The beginnings of the inactivity time durations (in-
`activity timeractive), indicated at 22 in FIG.2, is referred to
`as “UE being scheduled” for UL or DL user data transmis-
`sion.
`
`[0044] One aspect of the herein disclosed subject matteris
`to implement a concept of discontinuous reception DRX ona
`[0055] The concept of on-duration means the period when
`system capable of carrier aggregation. For an LTE (Long
`on-duration timer is running, and the concept of inactivity-
`Term Evolution) system an example of a DRX scheme has
`timer meansthe period when DRX inactivity timer is running.
`been proposed by the third generation partnership project
`Further, the joint operation of on-duration timer and DRX
`(3GPP) in TS 36.300 V8.6.0 (September 2008).
`inactivity timer in case a new transmission occurs in on-
`
`[0045] FIG.2showsanillustration of on-duration andinac-
`duration or when DRX inactivity timer is running is given
`tivity timer in a known LTE system.
`(similar to 3GPP TS 36.321):
`[0046]
`Asillustrated in 3GPP TS 36.300 [2], in the discon-
`[0056] According to an embodiment, when DRX is config-
`tinuous reception (DRX) procedure, “when a DRX cycle is
`ured, the UE shall for each subframe (wherein SFN is thecell
`configured, the active time includes the time while the on
`system frame number):
`duration timer or the DRX inactivity timer or a DRX retrans-
`[0057]
`If the short DRX cycle is used and [(SFN*10)+
`mission timer or the contention resolution timer is running.”
`subframe number] modulo (Short DRX Cycle)}=-DRX
`Start Offset;
`In this document, on-duration (on-duration timer), inactivity-
`[0058]
`or
`timer (DRX inactivity timer) and active-time are the basic
`if the long DRX cycle is used and [(SFN*10)+
`concepts in DRX procedures, as defined below. These defi-
`[0059]
`nitions are also valid for an illustrative embodiment of the
`subframe number] modulo (long DRX cycle)=-DRX
`start offset:
`herein disclosed subject matter, without being limited to the
`framework of LTE:
`
`[0060]
`
`start the on-duration timer.
`
`8
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`

`US 2011/0267957 Al
`
`Nov. 3, 2011
`
`Inthe following, two exemplary approaches will be
`[0078]
`described, each of which embodies various embodiments of
`the herein disclosed subject matter. Although in each
`approach a
`specific
`combination of embodiments
`is
`described, those skilled in the art will readily recognize that
`other combinationsof features are also possible and arereal-
`izable within the scope of the appendedclaims.
`[0079] A first approach described hereinafter is referred to
`as “dynamic DRX”. Within this approach,it is defined that:
`[0080]
`1.1 On-duration exists only on primary component
`carrier; and
`[0081]
`1.2: Inactivity-timer can bestarted or restarted on a
`secondary component carrier upon the indication of new
`transmission in primary componentcarrier’s PDCCH, only
`within active-time (when either on-duration timer or DRX
`inactivity timer is running) on the primary componentcarrier.
`[0082] The detailed rules for an exemplary implementation
`of the first approach are as follows:
`[0083] Rule 1.1: On-duration is configured only on primary
`componentcarrier 2a but not on any secondary component
`carriers 2b. During on-duration, UE is awake monitoring
`PDCCH on primary component carrier and is sleeping on
`secondary componentcarriers.
`[0084] Rule 1.2: When UEis monitoring PDCCH,ifa new
`transmission is configured on primary componentcarrier,
`eNBshall send an indication in the primary componentcar-
`rier’s PDCCHand UEstartsor restarts DRX inactivity timer
`on primary componentcarrier upon successfully decoding
`the PDCCH.
`
`if the DRX inactivity timer expires or a DRX
`[0061]
`Command MACcontrol elementis received in this sub-
`frame:
`ifthe short DRX cycle is configured:
`[0062]
`start or restart the DRX short cycle timer;
`[0063]
`use the short DRX cycle.
`[0064]
`else:
`[0065]
`use the long DRX cycle.
`[0066]
`[0067]
`during the active time, for a PDCCH-subframe
`except if the subframe is required for uplink transmis-
`sion for half-duplex FDD UE operation and exceptif the
`subframeis part of a configured measurementgap:
`[0068] monitor the PDCCH;
`[0069]
`if the PDCCHindicates a new transmission (DL
`or UL):
`start or restart the DRX inactivity timer.
`[0070]
`[0071] Now referring to a system with aggregated carriers
`according to an illustrative embodiment of the herein dis-
`closed subject matter, one PDCCHis provided for signaling
`the allocations for all componentcarriers jointly, where the
`componentcarrier containing PDCCHis herein referredto as
`“primary componentcarrier” and the other componentcarri-
`ers without PDCCHarereferred to as “secondary component
`carrier”.
`
`three
`FIG. 3 shows one joint PDCCH for all
`[0072]
`depicted componentcarriers 2. It should be understood that
`the number of componentcarriers 2 shown in FIG.3 is only
`for illustrative purposes can widely vary. In FIG. 3 onepri-
`mary component carrier 2a and two secondary component
`carriers 25 are shown.Perdefinition, the primary component
`carrier 2a has associated therewith a PDCCH24for signaling
`the allocations for all aggregated componentcarriers, the
`signaling being indicated at 26 in FIG. 3. Arrows 28a, 285
`indicate the component carrier bandwidth (BW)of primary
`and secondary componentcarriers 2a, 2b, respectively. Allo-
`cated resourcesare indicated at 30 in FIG.3.
`
`[0073] According to an illustrative embodiment, generally,
`on-duration as defined above is configured for the primary
`componentcarrier, while the inactivity timeras defined above
`is configured for both the primary and the secondary compo-
`nent carriers.
`
`[0085] Rule 1.3: When UEis monitoring PDCCH,ifa new
`transmission is configured on secondary componentcarriers,
`then two options are followed:
`[0086]
`If PDCCH on primary componentcarrier can
`configure the transmission in the following subframes
`far away enough to awaken secondary componentcar-
`rier,
`new transmission can be indicated directly by
`[0087]
`PDCCHat eNB, and UEstarts or restarts DRX inac-
`tivity timer on both primary and secondary compo-
`nent carriers a gap after successfully decoding the
`In this case, because there is no on-duration on
`[0074]
`PDCCH,i.e. from the subframe when the data trans-
`secondary componentcarrier in this embodiment, the defini-
`mission happens.
`tions of on-duration and inactivity-timer given above should
`[0088] A gap between PDCCHindication and data
`be adapted as follows to be compatible for both primary and
`transmission needs to be configured by RRC signal-
`secondary componentcarriers.
`ing explicitly or used by UEitself implicitly.
`[0075] On-duration: duration, e.g. in downlink subframes,
`[0089] Otherwise, if PDCCH on primary component
`that the UE waits for, after waking up from DRX,to receive
`carrier can only configure the transmission in the same
`PDCCHsif configured otherwise to receive downlink data. If
`subframe,
`the UE successfully decodes a PDCCH,the UE stays awake
`[0090]_first, a message(e.g., by MAC control element
`and starts the inactivity timer on the componentcarrier(s)
`(CE) or RRC message) is sent by eNB to make UE
`where the PDCCHis located and the componentcarrier(s)
`start the reception on the corresponding secondary
`wherethe indicated DL or UL transmission is configured.
`componentcarrier;
`[0076]
`Inactivity-timer: duration, e.g.
`in downlink sub-
`[0091]
`secondly, an indication of new transmission in
`frames, that the UE waits to successfully decode a PDCCH,
`PDCCHis sent a gap after sending the MAC CE/RRC
`from the last successful decoding of a PDCCH,failing which
`message from eNB, and UEstarts or restarts DRX
`it re-enters DRX. The UEshall restart the inactivity timer
`inactivity timer on both primary and secondary com-
`following a single successful decoding ofa PDCCHfora first
`ponent
`carriers
`immediately upon successfully
`transmission only (i.e. not for retransmissions). These proce-
`decoding the PDCCH.
`dures are valid only on the componentcarrier(s) where the
`PDCCHis located and the componentcarrier(s) where the
`FIG. 4 shows an exemplary procedure of dynamic
`[0092]
`indicated DL or UL transmission is configured.
`DRX design. Three cases are considered therein which cor-
`[0077] However, it should be noted that according to other
`respondto the rules 1.1, 1.2 and 1.3 above. In FIG. 4,a DRX
`embodiments, other timer configurationsare possible.
`cycle is indicated at 101.
`
`9
`
`

`

`US 2011/0267957 Al
`
`Nov. 3, 2011
`
`[0093] Case 1: If a new transmission happens on primary
`componentcarrier then the following steps are performed:
`[0094]
`Step 1: for eNB, new transmission indication is
`sent in primary componentcarrier’s PDCCH 124a, indi-
`cating the transmission on primary componentcarrier
`102a; and
`[0095]
`Step 2: for UE, during active-time on primary
`component carrier 102a, if a PDCCH indication for
`primary componentcarrier is received, DRX inactivity
`timer is started on primary componentcarrier in the
`same subframe. In FIG. 4, the active-time on primary
`componentcarrier is not explicitly indicated, but given
`by the time duration whereatleast one ofthe on-duration
`timer 108 and theinactivity timer 112ais active (respec-
`tive high levels in FIG.4).
`[0096] According to illustrative embodiments of case 1,
`indicated at d-CS1 in FIG.4, if anew transmission happensat
`primary componentcarrier 102a, then DRX inactivity timer
`is started in the same subframe.
`
`DRX inactivity timer 112c-1, 112c-2 is started or
`restarted on both primary and secondary component
`carriers 102a, 1025-2.
`[0106] According to illustrative embodiments of case 3,
`indicated at d-Cs3 in FIG.4, if a new transmission happensat
`secondary componentcarrier 1025-2, then
`[0107]
`1)aMAC/RRC messageis sent at primary com-
`ponent carrier to awaken secondary componentcarrier,
`indicated at 1) in FIGS. 4, and
`in
`[0108]
`2) a new transmission indication is sent
`PDCCHfor a transmission to begin, and DRX inactivity
`timeris started or restarted at both primary and second-
`ary componentcarriers 102a, 1025-2, indicated at 2) in
`FIG.4.
`
`If transmission on multiple secondary component
`[0109]
`carriers needs to be scheduled, eNB can send indications in
`PDCCHto start or restart DRX inactivity timer on these
`secondary componentcarriers simultaneously.
`[0110]
`It should be noted, that the three cases of the first
`approach indicated above may happentogetheror separately.
`[0097] Case 2: If a new transmission happens onafirst
`[0111] A second approach described hereinafter is referred
`secondary componentcarrier 1025-1 then the following steps
`to as “semi-persistent DRX”. Within this approach,
`it is
`defined that:
`are performed:
`[0098]
`Step 1: For eNB, a new transmission indicationis
`sent in primary componentcarrier’s PDCCH 1244,indi-
`cating the transmission on secondary componentcarrier
`1025-1;
`[0099]
`Step 2: for UE, during active-time on primary
`componentcarrier 102a, if a PDCCH 1246 indication
`for secondary componentcarrier 1025-1 is received, a
`timing gap 132 is used until the reception on secondary
`component carrier 1 is available (according to an
`embodiment shown in FIG. 4, the timing gap 132 is
`between PDCCHindication and data transmission);
`[0100]
`Step 3: DRX inactivity timer 1126-1, 112-2 is
`started or restarted on both primary componentcarrier
`102a and secondary componentcarrier 1025-1, respec-
`tively.
`[0101] According to illustrative embodiments of case 2,
`indicated at d-CS2 in FIG.4, if anew transmission happensat
`the first secondary componentcarrier 1025-1, then a timing
`gap is needed to guarantee secondary component carrier
`awake when transmission begins and DRX inactivity timeris
`started or restarted on both primary and secondary compo-
`nent carriers 102a, 1025-1.
`[0102] Case 3: If a new transmission happens on a second
`secondary componentcarrier 1025-2 then the following steps
`are performed:
`[0103]
`Step 1: foreNB, a MAC CE or RRC message 134
`(i.e. a MACcontrol element) is sent on primary compo-
`nentcarrier 102a indicating signal reception on second-
`ary componentcarrier 1025-2;
`[0104]
`Step 2: for eNB, new transmission indication
`124c is sent in primary component carrier’s PDCCH,
`indicating transmission on secondary componentcarrier
`1025-2, after a timing gap 138 (i.e. according to an
`illustrative embodiment, the timing gap 138 extends
`between the message indicating signal reception on sec-
`ondary componentcarrier 1026-2 and the PDCCHindi-
`cation);
`[0105]
`Step 3: for UE, during active-time on primary
`componentcarrier 102a, ifa PDCCH indication 124c for
`a secondary component carrier 1025-2 is received, a
`
`2.1: On-duration exists, i.e. an on-du