(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2010/0260136 A1
`
`
` Fan et al. (43) Pub. Date: Oct. 14, 2010
`
`US 20100260136A1
`
`(54) RANDOM ACCESS CHANNEL RESPONSE
`HANDLING WITH AGGREGATED
`COMPONENT CARRIERS
`
`Publication Classification
`
`(51)
`
`Int C1
`H04W 72/04
`
`(2009.01)
`
`(75)
`
`InVemorS:
`
`Jianke Fa“, E51300 (F1);J“ha 5'
`Korhonen, Espoo (Fl); Mikko J.
`Rinne, Espoo (Fl); Esa M.
`Malkamaki, Espoo (Fl)
`
`Correspondence Address:
`HARRINGTON & SMITH
`4 RESEARCH DRIVE, Suite 202
`SHELTON, CT 06484-6212 (US)
`
`(73) Assignee:
`
`Nokia Corporation
`
`(21) Appl. No.:
`
`12/334,950
`
`(22)
`
`Filed;
`
`Apr. 10, 2009
`
`(52) US. Cl. ........................................................ 370/330
`
`(57)
`
`ABSTRACT
`
`Disclosed herein are methods, computer program instruc-
`tions and apparatus for performing random access procedures
`in a. vyireless communication system: A .method includes
`receIVIng at a network access node, in different time and
`frequency resources that are allocated for preamble transmis-
`sion, and in different ones of a plurality of component carri-
`ers, a plurality of random access requests from individual
`ones of a plurality of user equipments; and transmitting a
`corresponding plurality of random access responses in a time
`and frequency resource of a single component carrier.
`
`MME/S—GW
`
`MME/S-GW
`
`E— UTRAN
`
`1
`
`SAMSUNG 1004
`
`SAMSUNG 1004
`
`1
`
`

`

`Patent Application Publication
`
`Oct. 14, 2010 Sheet 1 0f 10
`
`US 2010/0260136 A1
`
`MME/S—GW
`
`MME/S-GW
`
`E— UTRAN
`
`2
`
`

`

`mmP
`
`amS
`
`US 2010/0260136 A1
`
`
`
`
`
`xz_._n5|oTv_z_._z;ooxz_._z;oonxz_._%.mEHHHE—HaaflfiglmEHEHEHHHHE%IIwHEHEHHHHHEEQBEE28-12%2958:28Mm2zm2<Em2
`
`
`.mEEEEEEEEHEIEIHmEEEEEEEHHE%HmEEEEEHEHHE%|
`pEEHHEEEEHE%H
`nEHEHEHHHHEIII
`
`
`
`”20m,25an033?:gas:9%.~20wmPo:
`
`
`mmemumsgnem.uzééé
`
`
`
`
`
`
`0IIIII//m.IIIIIIIIIIIIIENBnwhomwnflnuemp“
`
`2III/I//53%
`ill-IIIIIIJIII
` ”20mmgmaa“Emma;“Ema9*“Emma;“Ema;”Egg“Emma%“Emma
`
`
`
`
`
`
`o_,.o_.._
`
`.E3mo.
`
`am@525m@525
`
`.mzéma
`
`mENBn
`
`3
`
`
`
`
`
`

`

`Patent Application Publication
`
`Oct. 14, 2010 Sheet 3 0f 10
`
`US 2010/0260136 A1
`
`l—l—l—i—l—l—l—l—l
`—oct I
`FIG.1 D
`
`
`
`HIRE“ Oct
`
`1
`
`FIG. 1 E
`
`
`
`u TIMING ADVANCE COMMAND oct 1
`
`TIMING ADVANCE
`COMMAND
`
`
`UL GRANT
`
`
`
`
`
`E/T/RAPID .
`E/T/RAPID
`SUBHEADER 1SUBHEADER 2
`
`.
`
`.
`
`E/T/RAPID
`SUBHEADER n
`
`/
`
`{—E/T/R/R/TBI
`I_SgB_HE_AQEB
`
`| l | l |
`
`l | ||
`
`
`
`4
`
`

`

`Patent Application Publication
`
`Oct. 14, 2010 Sheet 4 of 10
`
`US 2010/0260136 A1
`
`i
`
`
`
`fixmogfizmmnjumE
`
`mmoOZo
`
` gohzzhoz
`
`
`
`AmvxmoabzEEO
`
`Ezmmzzi
`
`mmZm$1.5o._.
`
`<N.o_u._
`
`zo_._.<._:n_om
`
`mm:no
`
`5
`
`

`

`Patent Application Publication
`
`Oct. 14, 2010 Sheet 5 0f 10
`
`US 2010/0260136 A1
`
`1]EE
`$5322:08
`
`<9
`
`5.
`
` ‘mag...
`E3E\\9//x.3
`
`6
`
`
`
`

`

`Patent Application Publication
`
`Oct. 14, 2010 Sheet 6 0f 10
`
`US 2010/0260136 A1
`
`LTE-ADVANCED MAXIMUM BANDWIDTH
`
`REL'8 BW
`REL'8 BW
`REL'B BW
`REL'8 BW
`
`REL'8 BW
`
`
`
`CARRIER 1
`
`CARRIER 2
`
`CARRIER 3
`
`CARRIER 4
`
`
`
`
`
`CARRIER 5
`
`
`
`FIG.3
`
`eNB
`
`FIG.4
`
`2mnannnnannnwm
`}15MH2
`mmnannunannnwm
`
`FIG.5
`
`7
`
`

`

`Patent Application Publication
`
`Oct. 14, 2010 Sheet 7 0f 10
`
`US 2010/0260136 A1
`
`
`
`
`
`.8mm:2.:mo...0259.;.5mm:2.:mo...zo:<2mo.._z_
`
`Eb:H.=.=.5mm:2.:mo...
`
`$8ozaoE._.<_.:umfijum
`
`m5“5m5E:.5mm:MEno;205522.
`
`mmfidmmESmwfidm$2..2.:
`02:55;Em<moE<
`mo;@253;EKG52
`
` Ill"1szmAHm-HHHn-Bngwwflismimm“-
`
`mwfidm$355:.umfidm595m5
`
`Nxzoxfimfimfiuaa§§§fia5N
`
`0.9L
`
`
`
`
`1|
`
`
`
`
`
`8
`
`
`

`

`Patent Application Publication
`
`Oct. 14, 2010 Sheet 8 0f 10
`
`US 2010/0260136 A1
`
`
`
`
`
`Niagamnmumfl5§§§flw=N12
`
`Nxzoom
`
`9
`
`
`

`

`Patent Application Publication
`
`Oct. 14, 2010 Sheet 9 0f 10
`
`US 2010/0260136 A1
`
`
`
`
`
`mmfidmEsmfiNE..._0
`
`
`
`
`
`m0;mhzmzocflzozxgHmzfimm
`
`
`
`
`
`mo;mhzuzoomgozxo"Hmzfimm
`
`
`
`
`
`mo;mpzmzooflaozxnéEmzfimm
`
`mmfidmEb)H.=.=..5mm:MT:
`
`mm:mE.E0259}.m<8920mm
`
`mmfidm35.5at.8mm:m5
`
`
`
`mmfijmm5::m5..._0mm:m5
`
`
`«BEE5.;.5mm:MI»E0259?.m<8920mm
`mmfidm
`
`FIG.9
`
`10
`
`10
`
`
`
`
`

`

`Patent Application Publication
`
`Oct. 14, 2010 Sheet 10 0f 10
`
`US 2010/0260136 A1
`
`RECEIVING AT A NETWORK ACCESS NODE,
`IN DIFFERENT TIME AND FREQUENCY
`RESOURCES THAT ARE ALLOCATED FOR
`PREAMBLE TRANSMISSION, AND IN DIFFERENT
`ONES OF A PLURALITY OF COMPONENT
`CARRIERS, A PLURALITY OF RANDOM ACCESS
`REQUESTS FROM INDIVIDUAL ONES OF A
`PLURALITY OF USER EQUIPMENTS
`
`TRANSMITTING A CORRESPONDING PLURALITY
`OF RANDOM ACCESS RESPONSES IN A TIME
`AND FREQUENCY RESOURCE OF A SINGLE
`COMPONENT CARRIER
`
`FIG.1O
`
`TRANSMITTING TO A NETWORK ACCESS NODE,
`IN A TIME AND FREQUENCY RESOURCE OF ONE
`OF A PLURALITY OF COMPONENT CARRIERS,
`A RANDOM ACCESS REQUEST
`
`
`
`
`
`RECEIVING A RANDOM ACCESS RESPONSE
`
`THAT IS AGGREGATED WITH OTHER RANDOM
`ACCESS RESPONSES IN A TIME AND FREQUENCY
`RESOURCE OF THE
`SAME OR A DIFFEREN
`COMPONENT CARRIER (OR A SAME OR
`DIFFERENT PAIRED COMPONENT CARRIER)
`
`FIG.1 1
`
`IN
`RECEIVING AT A NETWORK ACCESS NODE,
`A TIME AND FREQUENCY RESOURCE ASSOCIATED
`WITH A FIRST FREQUENCY BAND, A RANDOM
`ACCESS REQUEST FROM A USER EQUIPMENT
`
`TRANSMITTING A CORRESPONDING RANDOM
`ACCESS RESPONSE IN A TIME AND FREQUENCY
`RESOURCE ASSOCIATED WITH A SECOND
`FREQUENCY BAND
`
`10A
`
`103
`
`“A
`
`113
`
`,
`
`,
`
`12A
`
`123
`
`FIG.12
`
`11
`
`11
`
`

`

`US 2010/0260136 A1
`
`Oct. 14, 2010
`
`RANDOM ACCESS CHANNEL RESPONSE
`HANDLING WITH AGGREGATED
`COMPONENT CARRIERS
`
`TECHNICAL FIELD
`
`[0001] The exemplary and non-limiting embodiments of
`this invention relate generally to wireless communication
`systems, methods, devices and computer programs and, more
`specifically, relate to random access channel signaling tech-
`niques between a mobile node and a network access node.
`
`BACKGROUND
`
`[0002] This section is intended to provide a background or
`context to the invention that is recited in the claims. The
`
`description herein may include concepts that could be pur-
`sued, but are not necessarily ones that have been previously
`conceived, implemented or described. Therefore, unless oth-
`erwise indicated herein, what is described in this section is not
`prior art to the description and claims 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 third generation partnership project
`[0004]
`[0005] DL downlink (eNB towards UE)
`[0006] DwPTS downlink pilot time slot
`[0007]
`eNB EUTRAN Node B (evolved Node B)
`[0008] EPC evolved packet core
`[0009] EUTRAN evolved UTRAN (LTE)
`[0010]
`FDD frequency division duplex
`[0011]
`FDMA frequency division multiple access
`[0012] GP guard period
`[0013] LTE long term evolution
`[0014] MAC medium access control
`[0015] MM/MME mobility management/mobility man-
`agement entity
`[0016] Node B base station
`[0017] OFDMA orthogonal frequency division multiple
`access
`
`[0018] O&M operations and maintenance
`[0019]
`PDCP packet data convergence protocol
`[0020]
`PDCCH physical downlink control channel
`[0021]
`PDSCH physical downlink shared channel
`[0022]
`PHY physical (layer 1)
`[0023]
`PRACH physical random access channel
`[0024] RA-RNTI random access radio network temporary
`identity
`[0025] RACH random access channel
`[0026] RLC radio link control
`[0027] RRC radio resource control
`[0028]
`SGW serving gateway
`[0029]
`SC-FDMA single carrier, frequency division mul-
`tiple access
`[0030] TDD time division duplex
`[0031]
`T—CRNTI temporary cell random access radio net-
`work temporary identity
`[0032] TTI transmission timing interval
`[0033] UE user equipment
`[0034] UL uplink (UE towards eNB)
`[0035] UpPTS uplink pilot time slot
`[0036] UTRAN universal terrestrial radio access network
`[0037] The specification of a communication system
`known as evolved UTRAN (EUTRAN, also referred to as
`
`UTRANLTE or as EUTRA) is currently nearing completion
`within the 3GPP. As specified the DL access technique is
`OFDMA, and the UL access technique is SC-FDMA.
`[0038] One specification of interest is 3GPP TS 36.300,
`V8.7.0 (2008-12), 3rd Generation Partnership Project; Tech-
`nical Specification Group Radio Access Network; Evolved
`Universal Terrestrial Radio Access (EUTRA) and Evolved
`Universal Terrestrial Access Network (EUTRAN); Overall
`description; Stage 2 (Release 8), incorporated by reference
`herein in its entirety. This system may be referred to for
`convenience as LTE Rel-8, or simply as Rel-8. In general, the
`set of specifications given generally as 3GPP TS 36.xyz (e. g.,
`36.211, 36.311, 36.312, etc.) may be seen as describing the
`entire Release 8 LTE system.
`[0039]
`FIG. 1A reproduces FIG. 4.1 of 3GPP TS 36.300,
`and shows the overall architecture of the EUTRAN system.
`The EUTRAN system includes eNBs, providing the EUTRA
`user plane (PDCP/RLC/MAC/PHY) and control plane
`(RRC) protocol terminations towards the UE. The eNBs are
`interconnected with each other by means of an X2 interface.
`The eNBs are also connected by means of an 81 interface to
`an EPC, more specifically to a MME (Mobility Management
`Entity) by means of a $1 MME interface and to a Serving
`Gateway (SGW) by means of a $1 interface. The $1 interface
`supports a many to many relationship between MMEs/Serv-
`ing Gateways and eNBs.
`[0040] The eNB hosts the following functions:
`[0041]
`functions for Radio Resource Management: Radio
`Bearer Control, Radio Admission Control, Connection
`Mobility Control, Dynamic allocation of resources to UEs in
`both uplink and downlink (scheduling);
`[0042]
`IP header compression and encryption of the user
`data stream;
`[0043]
`selection of a MME at UE attachment;
`[0044]
`routing of User Plane data towards Serving Gate-
`way;
`scheduling and transmission of paging messages
`[0045]
`(originated from the MME);
`[0046]
`scheduling and transmission of broadcast informa-
`tion (originated from the MME or O&M); and
`[0047]
`a measurement and a measurement reporting con-
`figuration for use in mobility and scheduling.
`[0048]
`In the present LTE system preamble responses are
`sent utilizing both the PDCCH and the PDSCH. Each RACH
`resource (time and frequency resource reserved for preamble
`transmission) is associated with a RA-RNTI (random access
`radio network temporary identity). When the base station
`(eNB) observes a preamble,
`it
`transmits the preamble
`response on the PDSCH on a resource that is indicated by a
`PDCCH addressed with the RA-RNTI. More specifically,
`when a Random Access Response message is transmitted, the
`CRC word of the corresponding PDCCH is masked by RA-
`RNTI. When searching a preamble response the UE tries to
`find a RA-RNTI masking corresponding to the frequency and
`time resource that the UE had used when sending its pre-
`amble. In this manner the preamble response on the PDSCH
`is unambiguously associated with preambles transmitted on a
`certain time-frequency resource.
`[0049] The system is flexible in the sense that the base
`station can acknowledge in the same PDSCH message several
`preambles that have been transmitted in the same RACH
`resource, but
`that carry different signatures (preamble
`sequences). In addition, the responses can be sent in a time
`window that is configurable up to a duration of 10 ms.
`
`12
`
`12
`
`

`

`US 2010/0260136 A1
`
`Oct. 14, 2010
`
`In the present LTE system the responses to a set of
`[0050]
`UEs that listen to the same RA-RNTI can be combined into
`
`the same message. However, responses corresponding to dif-
`ferent RA-RNTI cannot be combined, and PDCCH and
`PDSCH messages must be sent separately for each RA-RNTI
`(i.e., each RACH time-frequency resource). Considering the
`limited PDCCH resources this is not an efficient procedure.
`Because the base station does not know the channel state of
`
`the UEs, a PDCCH entry for a preamble response must be
`heavily coded, which consumes
`significant PDCCH
`resources. This can lead to problems, especially in the TDD
`system of LTE where several PRACH resources can exist in
`one subframe, and where random access responses cannot be
`distributed in time as flexibly as in the FDD system. This is
`true at least for the reason that in the TDD system there are
`gaps in the PDCCH due to subframes reserved for UL.
`[0051] One LTE specification of interest herein is 3GPP TS
`36.21 1 V8.5 .0 (2008-12) Technical Specification 3rd Genera-
`tion Partnership Project; Technical Specification Group
`Radio Access Network; Evolved Universal Terrestrial Radio
`Access (E-UTRA); Physical channels and modulation (Re-
`lease 8).As is stated in subclause 4.2, the frame structure type
`2 is applicable to TDD.
`[0052] The PRACH is described in subclause 5.7 of 3GPP
`TS 36.211 V8.5.0.
`
`[0053] Another LTE specification of interest herein is
`3GPP TS 36.321 V8.5.0 (2009-03) Technical Specification
`3rd Generation Partnership Project; Technical Specification
`Group Radio Access Network; Evolved Universal Terrestrial
`Radio Access (EUTRA); Medium Access Control (MAC)
`protocol definition (Release 8). The specification describes in
`subclause 5 .1 the overall Random Access procedure followed
`by the UE, in subclause 5.1.3 the Random Access Preamble
`transmission, and in subclause 5.1.4 the Random Access
`Response reception.
`[0054]
`For example, as currently specified for Rel-8 in sub-
`clause 5.1.4 “Random Access Response reception”, once the
`RandomAccess Preamble is transmitted and regardless ofthe
`possible occurrence of a measurement gap, the UE shall
`monitor the PDCCH for Random Access Response(s) iden-
`tified by the RA-RNTI defined below, in the RA Response
`window which starts at the subframe that contains the end of
`
`the preamble transmission plus three subframes and has
`length ra-ResponseWindowSize subframes. The RA-RNTI
`associated with the PRACH in which the Random Access
`
`Preamble is transmitted, is computed as:
`RA-RNTI:1+l,id+10 >“fjd,
`
`where t_id is the index of the first subframe of the specified
`PRACH (0§t_id<10), and f_id is the index of the specified
`PRACH within that subframe, in ascending order of fre-
`quency domain (0§f_id<6). The UE may stop monitoring for
`Random Access Response(s) after successful reception of a
`Random Access Response containing Random Access Pre-
`amble identifiers that matches the transmitted Random
`Access Preamble.
`
`It is further specified in subclause 5.1.4 that if a
`[0055]
`downlink assignment for this TTI has been received on the
`PDCCH for the RA-RNTI, and the received TB is success-
`fully decoded, the UE shall regardless of the possible occur-
`rence of a measurement gap: ifthe Random Access Response
`contains a Backoff Indicator subheader:
`
`set the backoff parameter value in the UE as indi-
`[0056]
`cated by the BI field of the Backoff Indicator subheader
`and Table 7.2-1,
`[0057]
`else, set the backoff parameter value in the UE to
`0 ms.
`
`Ifthe Random Access Response contains a Random
`[0058]
`Access Preamble identifier corresponding to the transmitted
`Random Access Preamble (see subclause 5.1.3), the UE shall
`consider this Random Access Response reception successful
`and process the received Timing Advance Command (see
`subclause 5.2) and indicate the preambleInitialReceivedTar-
`getPower and the amount of power ramping applied to the
`latest preamble transmission to lower layers (i.e., (PRE-
`AMBLE_TRANSMISSION_COUNTER—1)*powerRamp-
`ingStep); process the received UL grant value and indicate it
`to the lower layers; if ra-PreambleIndex was explicitly sig-
`naled and it was not 000000 (i.e., not selected by MAC)
`consider the Random Access procedure successfully com-
`pleted.
`If no Random Access Response is received within
`[0059]
`the RA Response window, or if none of all received Random
`Access Responses contains a RandomAccess Preamble iden-
`tifier corresponding to the transmitted Random Access Pre-
`amble, the Random Access Response reception is considered
`not successful and the UE shall, among other activities, if in
`this Random Access procedure the RandomAccess Preamble
`was selected by MAC: based on the backoff parameter in the
`UE, select a random backoff time according to a uniform
`distribution between 0 and the Backoff Parameter Value;
`delay the subsequent Random Access transmission by the
`backoff time; and proceed to the selection of a Random
`Access Resource (see subclause 5.1.2).
`[0060] Of particular interest herein are the further releases
`of 3GPP LTE targeted towards future IMT-A systems,
`referred to herein for convenience simply as LTE-Advanced
`(LTE-A).
`[0061] Reference can be made to 3GPP TR 36.913, V8.0.1
`(2009-03), 3rd Generation Partnership Project; Technical
`Specification Group Radio Access Network; Requirements
`for Further Advancements for E-UTRA (LTE-Advanced)
`(Release 8), incorporated by reference herein in its entirety.
`One element of the LTE-A system is the proposed use of the
`UHF band (698-960 MHZ, referred to simply as 900 MHZ)
`and a 2.3 GHZ band (referred to simply as 2 GHZ).
`
`SUMMARY
`
`[0062] The foregoing and other problems are overcome,
`and other advantages are realized, by the use ofthe exemplary
`embodiments of this invention.
`
`In a first aspect thereofthe exemplary embodiments
`[0063]
`ofthis invention provide a method that comprises receiving at
`a network access node,
`in different time and frequency
`resources that are allocated for preamble transmission, and in
`different ones of a plurality of component carriers, a plurality
`of random access requests from individual ones of a plurality
`of user equipments; and transmitting a corresponding plural-
`ity of random access responses in a time and frequency
`resource of a single component carrier.
`[0064]
`In another aspect thereof the exemplary embodi-
`ments ofthis invention provide an apparatus that comprises a
`controller configured to operate with a wireless receiver and
`a wireless transmitter. The controller is further configured to
`respond to a reception in different
`time and frequency
`resources that are allocated for preamble transmission, and in
`
`13
`
`13
`
`

`

`US 2010/0260136 A1
`
`Oct. 14, 2010
`
`different ones of a plurality of component carriers, a plurality
`of random access requests from individual ones of a plurality
`of user equipments and to transmit a corresponding plurality
`of random access responses in a time and frequency resource
`of a single component carrier.
`[0065]
`In yet another aspect thereofthe exemplary embodi-
`ments of this invention provide a method that comprises
`receiving at a network access node, in a time and frequency
`resource associated with a first frequency band, a random
`access request from a user equipment; and transmitting a
`corresponding random access response in a time and fre-
`quency resource associated with a second frequency band.
`[0066]
`In yet another aspect thereofthe exemplary embodi-
`ments of this invention provide a method that comprises
`transmitting to a network access node, in a time and frequency
`resource ofone of a plurality of component carriers, a random
`access request; and receiving a random access response that is
`aggregated with other random access responses in a time and
`frequency resource of the same or a different component
`carrier.
`
`In yet another aspect thereofthe exemplary embodi-
`[0067]
`ments of this invention provide an apparatus that comprises a
`controller configured to operate with a wireless receiver and
`a wireless transmitter, where the controller is further config-
`ured to transmit to a network access node in a time and
`
`frequency resource allocated for preamble transmission, of
`one of a plurality of component carriers, a random access
`request, and to receive a random access response that is aggre-
`gated with other random access responses in a time and fre-
`quency resource of the same or a different component carrier.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`In the attached Drawing Figures:
`[0068]
`FIG. 1A reproduces FIG. 4 of 3GPP TS 36.300 V
`[0069]
`8.7.0, and shows the overall architecture of the EUTRAN
`system.
`FIG. 1B reproduces Table 4.2-2 of3GPP TS 36.211
`[0070]
`V8.5.0: Uplink-downlink configurations for the frame struc-
`ture type 2.
`[0071]
`FIG. 1C reproduces FIG. 4.2-1 of 3GPP TS 36.211
`V850, and shows the frame structure type 2.
`[0072]
`FIGS. 1D-1G reproduce FIGS. 615-1 through 6.1.
`5-4 of 3GPP TS 36.321 V850, and show the E/T/RAPID
`MAC subheader, the E/T/R/R/BI MAC subheader, the MAC
`RAR and an example of a MAC PDU containing a MAC
`header and MAC RARs, respectively.
`[0073]
`FIG. 2A shows a simplified block diagram of vari-
`ous electronic devices that are suitable for use in practicing
`the exemplary embodiments of this invention.
`[0074]
`FIG. 2B shows a more particularized block diagram
`of a UE such as that shown at FIG. 2A.
`
`FIG. 3 depicts a contiguous configuration of com-
`[0075]
`ponent carriers.
`[0076]
`FIG. 4 shows an eNB operable with two UEs of
`different capability in a non-contiguous carrier aggregation
`network.
`
`FIG. 5 shows an exemplary TDD CC configuration.
`[0077]
`FIG. 6 shows one exemplary embodiment of a sig-
`[0078]
`naling scheme to provide additional information for those
`UEs 10 of a later release that is sent in a portion of a message
`that the UEs 10 of an earlier release regard as padding.
`[0079]
`FIG. 7 shows an example of PRACH response for
`the non-contiguous carrier network.
`
`FIG. 8 shows an example of PRACH response for
`[0080]
`the non-contiguous carrier network in accordance with the
`exemplary embodiments of this invention.
`[0081]
`FIG. 9 depicts two exemplary embodiments (la-
`beled A and B for convenience) of the merging of preamble
`responses for UEs ofdiffering capabilities in accordance with
`the exemplary embodiments of this invention.
`[0082]
`FIGS. 10, 11 and 12 are each a logic flow diagram
`that illustrates the operation ofmethods, and a result of execu-
`tion of computer program instructions embodied on a com-
`puter readable memory, in accordance with the exemplary
`embodiments of this invention.
`
`DETAILED DESCRIPTION
`
`[0083] References herein to a Rel-8 UE generally encom-
`pass those UEs that are compatible with the set of LTE Rel-8
`specifications, including 3GPP TS 36.211 V850 and 3GPP
`TS 36.321 V8.5.0. References herein to a Rel-9 UE generally
`encompass those UEs that are generally compatible with the
`set of LTE Rel-8 specifications, including 3GPP TS 36.211
`V850 and 3GPP TS 36.321 V8.5.0, but that may include
`additional functionality that is not expressly specified for
`Rel-8 operation. References herein to an LTE-A UE generally
`encompass those UEs that may be considered as beyond
`Rel-8 or Rel-9 UEs.
`
`In LTE-A it is proposed that the total system band-
`[0084]
`width may have from two to five component carriers (CCs).
`These CCs can be contiguous as shown in FIG. 3, where there
`are five CCs shown each having the Rel-8 bandwidth, or
`non-contiguous as shown in FIGS. 4 and 5 (note in FIGS. 4
`and 5 that the CCs are from two separated bands, e.g., one
`bandwidth of 10 MHZ is from 2 GHZ and another bandwidth
`of 5 MHZ is from 900 MHZ and, in total, the bandwidth ofthe
`two CCs is 15 MHZ, and are non-contiguous). At least in the
`case of non-contiguous carriers, the TDD UL/DL configura-
`tions may be different in the different carriers, as is shown
`more particularly in FIG. 5. In FIGS. 4 and 5 “D” indicates a
`downlink subframe, “U” indicates an uplink subframe, and
`“S” indicates a special subframe (see, generally 3GPP TS
`36.211V8.5.0, subclause 4.2 “Frame structure type 2”). FIG.
`1B herein reproduces Table 4.2-2 of3GPP TS 36.211V8.5.0:
`Uplink-downlink configurations for the frame structure type
`2. FIG. 1C reproduces FIG. 4.2-1 3GPP TS 36.211 V850,
`and shows the frame structure type 2. The special subframe S
`has three fields: DwPTS, GP and UpPTS. The length of
`DwPTS and UpPTS is given by Table 4.2-1 of 3GPP TS
`36.211 V8.5.0, subject to the total length of DwPTS, GP and
`UpPTS being equal to 30720-TS:1 ms. Each subframe i is
`defined as two slots, 2i and 2i+1 oflength Tslot:15360.Ts:0’5
`ms in each subframe. Uplink-downlink configurations with
`both 5 ms and 10 ms downlink-to-uplink switch-point peri-
`odicity are supported. In the case of 5 ms downlink-to-uplink
`switch-point periodicity, the special subframe S exists in both
`half-frames. In the case of 10 ms downlink-to-uplink switch-
`point periodicity, the special subframe S exists in the first
`half-frame only. Subframes 0 and 5 and DwPTS are always
`reserved for downlink transmission. UpPTS and the subframe
`immediately following the special subframe are always
`reserved for uplink transmission.
`[0085]
`In the first step ofa RandomAccess (RA) procedure,
`the UE selects a CC and transmits a preamble sequence on
`that CC using a frequency and time resource reserved for
`preambles. The UE then searches for a preamble response
`
`14
`
`14
`
`

`

`US 2010/0260136 A1
`
`Oct. 14, 2010
`
`indicating that the base station has observed the preamble and
`that the UE is allowed to continue the RA procedure.
`[0086] The exemplary embodiments of this invention pro-
`vide an efficient technique for the signaling of the preamble
`responses over aggregated carriers.
`[0087] A straightforward generalization of the RA proce-
`dure for LTE-A with more than one CC would be such that
`
`preambles, observed on different CCs, are acknowledged
`separately by the base station (e.g., by the eNB). That is, when
`a preamble is observed in the UL of a CC, the acknowledg-
`ment is sent in the DL of the same CC (for TDD) or in the DL
`CC paired with the UL CC (for FDD). While this may be the
`simplest approach, it does not provide a most eflicient and
`flexible system for at least the following reasons.
`[0088] Note first that in the FDD case there are pairs of UL
`and DL carriers, and the response is sent in the paired DL
`carrier. However, for LTE-A this is not necessarily the case, as
`there may be more or fewer UL carriers than DL carriers.
`Furthermore, even when there are an equal number ofUL and
`DL carriers available, a specific UE maybe allocated only a
`part of those carriers (possibly a different number in UL and
`DL). For example, for LTE-A one of the DL component
`carriers could be considered as a primary component carrier
`and random access responses could be sent via this one com-
`ponent carrier only, whereas the random access request could
`be sent via any available UL component carrier.
`[0089] As a first reason, PDCCH resources are not used
`efliciently since a PDCCH entry is needed per each carrier
`with an observed preamble.
`[0090]
`Second, the use of this technique may result in a
`delay ifthe preamble response must be postponed by the eNB
`due to a lack of PDCCH resources.
`
`[0091] Third, PDSCH resources are not utilized in the most
`eflicient manner because many small response messages are
`sent instead of one larger message.
`[0092]
`Furthermore, there is little or no flexibility in select-
`ing a most suitable CC for sending the RA response. For
`example, the base station (eNB) may be forced to send the
`response in a CC having few DL sub-frames (it may be
`assumed that UL/DL configurations can be different at least
`in the case of non-contiguous CC configurations), or in a CC
`with a large PDCCH load due to a large number of UEs to
`schedule.
`
`In addition, the foregoing approach does not support
`[0093]
`a system where all of the RA preambles would be acknowl-
`edged in a primary CC that all of the UEs would be listening
`to. That is, even if the preamble would be sent on another CC
`(in order to distribute the RA load) the UEs would never need
`to listen to more than one CC in the DL. The use of the
`
`conventional approach would assume having to resume lis-
`tening to the CC paired with the UL carrier on which the
`preamble has been sent
`(when expecting a preamble
`response), or receiving from more than one CC.
`[0094] An efficient and flexible system for carrying pre-
`amble responses is thus needed for with the use of multiple
`CCs, such as in LTE-A.
`[0095] Before describing in further detail the exemplary
`embodiments of this invention, reference is made to FIG. 2A
`for illustrating a simplified block diagram of various elec-
`tronic devices and apparatus that are suitable for use in prac-
`ticing the exemplary embodiments of this invention. In FIG.
`2A a wireless network 1 is adapted for communication over a
`wireless link 11 with an apparatus, such as a mobile commu-
`nication device which may be referred to as a UE 10, via a
`
`network access node, such as a Node B (base station), and
`more specifically an eNB 12. The network 1 may include a
`network control element (NCE) 14 that may include the
`MME/SGW functionality shown in FIG. 1A, and which pro-
`vides connectivity with a network 1, such as a telephone
`network and/or a data communications network (e.g., the
`internet). The UE 10 includes a controller, such as a computer
`or a data processor (DP) 10A, a computer-readable memory
`medium embodied as a memory (MEM) 10B that stores a
`program of computer instructions (PROG) 10C, and a suit-
`able radio frequency (RF) transceiver 10D for bidirectional
`wireless communications with the eNB 12 via one or more
`antennas. The eNB 12 also includes a controller, such as a
`computer or a data processor (DP) 12A, a computer-readable
`memory medium embodied as a memory (MEM) 12B that
`stores a program of computer instructions (PROG) 12C, and
`a suitable RF transceiver 12D for communication with the UE
`
`10 via one or more antennas. The eNB 12 is coupled via a
`data/control path 13 to the NCE 14. The path 13 may be
`implemented as the S1 interface shown in FIG. 1A. The eNB
`12 may also be coupled to another eNB via data/control path
`15, which may be implemented as the X2 interface shown in
`FIG. 1A.
`
`[0096] At least one of the PROGs 10C and 12C is assumed
`to include program instructions that, when executed by the
`associated DP, enable the device to operate in accordance
`with the exemplary embodiments of this invention, as will be
`discussed below in greater detail.
`[0097] That is, the exemplary embodiments of this inven-
`tion maybe implemented at least in part by computer software
`executable by the DP 10A ofthe UE 10 and/or by the DP 12A
`of the eNB 12, or by hardware, or by a combination of soft-
`ware and hardware (and firmware).
`[0098]
`For the purposes of describing the exemplary
`embodiments of this invention the UE 10 may be assumed to
`also include a RACH function or module 10E, and the eNB 12
`also includes a corresponding RACH function or module
`12E, both ofwhich are configured for operation in accordance
`with the exemplary embodiments of this invention.
`[0099] The UE 10 may be a Rel-8 compatible UE, or a later
`than Rel-8 UE, such as a Rel-9 or an LTE-A compatible UE.
`In general, there will be some population ofUEs 10 served by
`the eNB 12, and the population may be mixed between UEs
`operating as Rel-8, Rel-9 and LTE-A UEs, as non-limiting
`examples.
`[0100]
`In general, the various embodiments of the UE 10
`can include, but are not limited to, cellular telephones, per-
`sonal digital assistants (PDAs) having wireless communica-
`tion capabilities, portable computers having wireless com-
`munication capabilities, image capture devices such as digital
`cameras having wireless communication capabilities, gam-
`ing devices having wireless communication capabilities,
`music storage and playback appliances having wireless com-
`munication capabilities, Internet appliances permitting wire-
`less Internet access and browsing, as well as portable units or
`terminals that incorporate combinations of such functions.
`[0101] The computer readable MEMs 10B and 12B may be
`of any type suitable to the local technical environment and
`may be implemented using any suitable data storage technol-
`ogy, 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 12A may be of any type suitable
`to the local technical environment, and may include one or
`
`15
`
`15
`
`

`

`US 2010/0260136 A1
`
`Oct. 14, 2010
`
`more of general purpose computers, special purpose comput-
`ers, microprocessors, digital signal processors (DSPs) and
`processors based on multi-core processor architectures, as
`non-limiting examples.
`[0102]
`FIG. 2B illustrates further detail of an exemplary
`UE 10 in both plan view (left) and sectional view (right), and
`the invention may be embodied in one or some combination
`of those more function-specific components. At FIG. 2B the
`UE 10 has a graphical display interface 20 and a user interface
`22 illustrated as a keypad but understood as also encompass-
`ing touchscreen technology at the graphical display interface
`20 and voice recognition technology received at the micro-
`phone 24. A power actuator 26 controls the device being
`turned on and offby the user. The exemplary UE 10 may have
`a camera 28 which is shown as being forward facing (e.g., for
`video calls) but may alternatively or additionally be rearward
`facing (e. g., for capturing images and video for local storage).
`The camera 28 is controlled by a shutter actuator 30 and
`optionally by a zoom actuator 30 which may alternatively
`function as a volume adjustment for the speaker(s) 34 when
`the camera 28 is not in an active mode.
`
`[0103] Within the sectional view of FIG. 2B are seen mul-
`tiple transmit/receive antennas