`
`(12) United States Patent
`Lindholm et a1.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 8,385,966 B2
`Feb. 26, 2013
`
`(54) METHOD, APPARATUS AND COMPUTER
`PROGRAM FOR POWER CONTROL
`RELATED TO RANDOM ACCESS
`PROCEDURES
`
`(75) Inventors: Jari Lindholm, Palojoki (FI); Juha S.
`Korhonen, Espoo (Fl)
`
`(73) Assignee: Nokia Siemens Networks Oy, Espoo
`(F1)
`
`( * ) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 587 days.
`
`(21) Appl.No.: 12/387,661
`
`(22) Filed:
`
`May 5, 2009
`
`(65)
`
`Prior Publication Data
`
`US 2009/0286566 A1
`
`Nov. 19, 2009
`
`Related US. Application Data
`
`(60) Provisional application No. 61/126,617, ?led on May
`5, 2008.
`
`(51) Int. Cl.
`(2006.01)
`H04B 7/00
`(52) US. Cl. ...................................... .. 455/522; 455/521
`(58) Field of Classi?cation Search ...................... .. None
`See application ?le for complete search history.
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`20033670272623 :1:
`$552123? al' ~~~~~~~~~~~~~~
`2003/0U9452 A1,. 600% Kim et a1
`" 455/69
`2004/0001429 A1 *
`1/2004 Ma et a1‘ ““ “
`n 370/210
`2007/0149206 Al* 6/2007 Wang et a1.
`.... .. 455/450
`2007/0201397 A1* 8/2007 Zhang ......................... .. 370/329
`
`OTHER PUBLICATIONS
`
`Editor (motorola), 3GPP Draft; 3rd generation partnership project,
`mobile competence centre; vol. RAN WGl, Feb. 15, 2008, whole
`document.*
`Interdigital Communications Corporation; “E-Ultra Uplink Power
`Control Proposal and Evaluation”; vol. RAN WG1, Jun. 22, 2007,
`whole document.*
`Editor (Motorola): 3GPP Draft; R1-081056i36213-81 O-CR, 3rd
`Generation Partnership Project (3GPP), Mobile Competence
`Centre ; 650, Route Des Lucioles ; F-06921 Sophia-Antipolis
`CedeX ; France, vol. RAN WGl, No. Sorrento, Italy; 20080215, Feb.
`15, 2008, XP050109512.*
`NTT Docomo et al: “Transmission Power Control in E-UTRA
`Uplink” 3GPP Draft; R1 -070870 Transmission Power Control in E
`UTRA Uplink, 3rd Generation Partnership Project (3GPP), Mobile
`Competence Centre ;650, Route Des Lucioles ; F- 06921 Sophia
`Antipolis CedeX ; France, vol. RANIWGl, No. St. Louis, USA;
`20070206, Feb. 6, 2007, XP05010.*
`(Continued)
`
`Primary Examiner * Crystal L Hammond
`(74) Attorney, Agent, or Firm * Harrington & Smith
`
`ABSTRACT
`(57)
`A ?rst power control adjustment state g(i) and a second power
`control adjustment state f(i) are initialized for i:0 to each
`re?ect an open loop power control error. An initial transmit
`power for a shared uplink channel is computed using full
`pathloss compensation. The computed initial transmit power
`depends on a preamble power of a ?rst message sent on an
`access channel, and the initial transmit power is initialized
`with the second power control adjustment state f(0). A third
`message is sent from a transmitter on an uplink shared chan
`nel at the initial transmit power. In various implementations,
`the power for i:0 on the uplink control channel is also initial
`iZed similar to the initial transmit power for the third message
`and using full pathloss compensation, and after the third
`message (and retransmissions of it), subsequent messages
`sent on the uplink shared channel are sent at a power that is
`computed using fractional pathloss compensation.
`
`17 Claims, 5 Drawing Sheets
`
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`
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`
`16
`
`WIRELESS NETWORK 1
`
`Page 1 of 15
`
`LG Electronics Exhibit 1001
`
`
`
`US 8,385,966 B2
`Page 2
`
`OTHER PUBLICATIONS
`
`IPWIRELESS: “Initial Access Procedure and Uplink Synchronisa
`tion” 3GPP Draft; Rl-060637, 3rd Generation Partnership Project
`(3GPP), Mobile Competence Centre ; 650, Route Des Lucioles ;
`F-0692l Sophia-Antipolis CedeX ; France, vol. RAN WGl, No.
`Denver, USA; 20060209, Feb. 9, 2006, XP050101560.*
`“3rd Generation Partnershp Project; Technical Speci?cation Group
`Radio Access Network; Evolved Universal Terrestrial Radio Access
`(E-UTRA) and Evolved Universal terrestrial Radio Access Network
`(E-UTRAN); Overall description; Stage 2 (Release 8)”. 3GPP TS
`36.300 V8.4.0 (Mar. 2008), 5 pgs.
`“3rd Generation Partnership Project; Technical Speci?cation Group
`Radio Access Network; Evolved Universal Terrestrial Radio Access
`(E-UTRA); Physical layer procedures (Release 8)”, 3GPP TS 36.2l3
`V8.2.0 (Mar. 2008), 30 pgs.
`Motorola: 3GPP Draft; Rl -08l056i362l3-8l0-CR, 3rd Generation
`Partnership Project (3GPP), Mobile Competence Centre; vol. RAN
`WGl, No. Sorrento, Italy; Feb. 15, 2008, XP050l095l2.
`NTT DoCoMo et al: “Transmission Power Control in E-UTRA
`Uplink” 3GPP Draft, Rl-070870; vol. RAN WGl, No. St. Louis,
`USA; Feb. 6, 2007, XP050104882.
`
`Qualcomm Europe: “RACH sequences and planning” 3GPP Draft;
`Rl -062690; vol. RAN WGl, No. Seoul, Korea; Oct. 4, 2006,
`XP050103179.
`IPWireless: “Initial Access Procedure and Uplink Synchronisation”
`3GPP Draft; Rl-060637; vol. RAN WGl, No. Denver, USA , Feb. 9,
`2006, XP050101560.
`NTT DoCoMo et al: “Transmission Power Control in E-UTRA
`Uplink” 3GPP Draft; Rl-0633 16; vol. RAN WGl, No. Riga, Latvia;
`Nov. 2, 2006, XP050103761.
`Interdigital Communications Corporation: “E-UTRA Uplink Power
`Control Proposal and Evaluation” 3GPP Draft; Rl-07278l; vol.
`RAN WGI, No. Orlando, USA; Jun. 22, 2007, XP050106465.
`Nokia et al: “Clari?cations on the Out-of sync handling for UTRA
`TDD” 3GPP Draft; Rl-00/l097; vol. RAN WGl, No. Berlin, Ger
`many; Aug. 27, 2000, XP050093021.
`3GPP TS 36.32l V8.0.0 (Dec. 2007) 3rd Generation Partnership
`Project; Technical Speci?cation Group Radio Access Network;
`Evolved Universal Terrestrial Radio Access (E-UTRA) Medium
`Access Control (MAC) protocol speci?cation (Release 8).
`
`* cited by examiner
`
`Page 2 of 15
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`
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`U.S. Patent
`
`Feb. 26,2013
`
`Sheet 1 of 5
`
`US 8,385,966 B2
`
`E— UTRAN
`
`FIG. 1A
`PRIOR ART
`
`Page 3 of 15
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`Page 3 of 15
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`US. Patent
`
`Feb. 26, 2013
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`Sheet 2 of5
`
`US 8,385,966 B2
`
`CONTENTION BASED RANDOM ACCESS PROCEDURE
`
`UE
`
`eNB
`
`@ RANDOM ACCESS PREAMBLE
`
`‘
`
`RANDOM ACCESS RESPONSE @
`
`@ SCHEDULED TRANSMISSION
`
`CONTENTION RESOLUTION
`
`@
`
`1%; 1R?
`
`NON-CONTENTION BASED RANDOM ACCESS PROCEDURE
`UE
`eNB
`
`@
`
`RA PREAMBLE ASSIGNMENT
`
`RANDOM ACCESS PREAMBLE
`
`* G)
`
`RANDOM ACCESS RESPONSE
`
`@ <
`
`FIG. 1 C
`PRIOR ART
`
`Page 4 of 15
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`
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`U.S. Patent
`
`Feb. 26,2013
`
`Sheet 3 of5
`
`US 8,385,966 B2
`
`(01—'
`
`TOOTHERS
`WIRELESSNEIWORK1/I
`
`
`F|G.2
`
`Page 5 of 15
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`Page 5 of 15
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`
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`U.S. Patent
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`Feb. 26, 2013
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`Sheet 4 of5
`
`US 8,385,966 B2
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`Page 6 of 15
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`US. Patent
`
`Feb. 26, 2013
`
`Sheet 5 of5
`
`US 8,385,966 B2
`
`COMPUTE THE PREAMBLE POWER USING FULL PATHLOSS
`CoMPENSATIoN
`
`,408
`
`II
`INITIALIZE FoR i=0 A FIRST POWER CoNTRoL ADJUSTMENT STATE
`9(0) FDR AN UPLINK CoNTRoL_ CHANNEL AND A SECOND POWER
`CONTROL ADJUSTMENT STATE f(|) FDR AN UPLINK SHARED CHANNEL
`TO EACH REFLECT AN OPEN LOOP POWER CDNTRDL ERROR ie.g.,
`EQUATION [40] AND [4b]}
`
`/402
`
`I
`COMPUTE AN INITIAL TRANSMIT POWER FOR THE UPLINK SHARED
`CHANNEL USING FULL PATHLOSS COMPENSATION {e.g., EQUATION [5]};
`- DEPENDS ON A PREAMBLE POWER OF A FIRST MESSAGE SENT
`ON AN UPLINK ACCESS CHANNEL §e.g., PREAMBLE POWER OF
`THE RACH ACCESS REQUEST PREAMBLE}.
`- INITIALIZED WITH THE SECOND POWER CONTROL ADJUSTMENT
`STATE f(O)
`
`404
`(
`
`THE THIRD MESSAGE HAS AN INDICATIDN DE A PowER DIFFERENCE
`BETWEEN THE INITIAL TRANSMIT POWER WHICH Is COMPUTED USING
`FULL PATHLOSS COMPENSATION AND A FRACTIONAL PATHLOSS
`COMPUTATION OF THE INITIAL TRANSMIT _PowER §e.g., DIFFERENCE
`BETWEEN EQUATIONS [5] AND [1] FoR I=o}
`
`412
`’
`
`II
`SEND THE THIRD MESSAGE f8. .. MESSAGE 3} ON THE UPLINK
`SHARED CHANNEL {e.g.. PUSCH AT THE INITIAL TRANSMIT POWER
`
`406
`
`COMPUTE AN UPDATED TRANSMIT POWER (FOR ALL MESSAGES
`AFTER MESSAGE 3 AND ANY OF ITS RE-TRANSMISSIONS) FOR THE
`PUSCH USING FRACTIONAL POWER CONTROL {e.g.. EQUATION
`FIG.4
`
`410
`
`Page 7 of 15
`
`
`
`US 8,385,966 B2
`
`1
`METHOD, APPARATUS AND COMPUTER
`PROGRAM FOR POWER CONTROL
`RELATED TO RANDOM ACCESS
`PROCEDURES
`
`CROSS-REFERENCE TO RELATED
`APPLICATION
`
`This patent application claims priority under 35 U.S.C.
`§119(e) from US. Provisional Patent Application No.
`61/126,617, ?led May 5, 2008, Which is hereby incorporated
`by reference herein in its entirety, including Exhibits.
`
`10
`
`TECHNICAL FIELD
`
`The exemplary and non-limiting embodiments of this
`invention relate generally to Wireless communication sys
`tems, methods, devices and computer programs and, more
`speci?cally, relate to techniques for poWer control on differ
`ent uplink messages sent from a communication device.
`
`BACKGROUND
`
`Various abbreviations that appear in the speci?cation and/
`or in the draWing ?gures are de?ned as folloWs:
`3GPP third generation partnership project
`DL doWnlink
`DRX discontinuous reception
`eNB EUTRAN Node B (evolved Node B)
`EUTRAN evolved UTRAN (also referred to as LTE)
`LTE long term evolution
`MAC medium access control
`MME mobility management entity
`Node B base station
`OFDMA orthogonal frequency division multiple access
`PC poWer control
`PDCCH physical doWnlink control channel
`PDCP packet data convergence protocol
`PDSCH physical doWnlink shared channel
`PHY physical
`PL path loss
`PRACH physical random access channel
`PUSCH physical uplink shared channel
`RACH random access channel
`RA-RNTI random access radio netWork temporary identi
`?er
`RLC radio link control
`RRC radio resource control
`SC-FDMA single carrier, frequency division multiple
`access
`TA timing advance
`UE user equipment
`UL uplink
`UTRAN universal terrestrial radio access netWork
`A proposed communication system knoWn as evolved
`UTRAN (E-UTRAN, also referred to as UTRAN-LTE,
`E-UTRA or 3 .9 G) is currently under development Within the
`3GPP. The current Working assumption is that the DL access
`technique Will be OFDMA, and the UL access technique Will
`be SC-FDMA.
`One speci?cation of interest to these and other issues
`related to the invention is 3GPP TS 36.300,V8.4.0 (2008-03),
`3rd Generation Partnership Project; Technical Speci?cation
`Group Radio Access Network; Evolved Universal Terrestrial
`Radio Access (E-UTRA) and Evolved Universal Terrestrial
`Access NetWork (E-UTRAN); Overall description; Stage 2
`(Release 8).
`
`20
`
`25
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`30
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`35
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`40
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`45
`
`50
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`55
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`60
`
`65
`
`2
`FIG. 1A reproduces FIG. 4-1 of 3GPP TS 36.300, and
`shoWs the overall architecture of the E-UTRAN system. The
`E-UTRAN system includes eNBs, providing the E-UTRA
`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 S1 interface to
`an EPC, more speci?cally to a MME (Mobility Management
`Entity) by means of a Sl-MME interface and to a Serving
`GateWay (S-GW) by means of a S1 -U interface. The S1
`interface supports a many-to-many relation betWeen MMEs/
`Serving GateWays and eNBs.
`Reference can also be made to 3GPP TS 36.321, V8.0.0
`(2007-12), 3rd Generation Partnership Project; Technical
`Speci?cation Group Radio Access NetWork; Evolved Univer
`sal Terrestrial Radio Access (E-UTRA) MediumAccess Con
`trol (MAC) protocol speci?cation (Release 8).
`Also of interest herein are the random access procedures of
`the LTE (E-UTRA) system. These procedures are described
`in 3GPP TS 36.300 v.8.4.0 at section 10.1.5 (attached to the
`priority document as Exhibit A), shoWn at FIG. 1B for the
`Contention Based Random Access Procedure and at FIG. 1C
`for the Non-Contention Based Random Access Procedure.
`These respectively reproduce FIGS. 10.1.5.1-1 and
`10.1.5.1-2 of 3GPP TS 36.300 V840, and Exhibit A of the
`priority document details the various steps shoWn.
`Brie?y, the UE transmits a random access preamble and
`expects a response from the eNB in the form of a so-called
`Message 2 (e.g., Random Access Response at FIGS. 1B and
`1C). Message 2 is transmitted on a DL shared channel DL
`SCH (PDSCH, the PDCCH) and allocates resources on an
`UL-SCH (PUSCH). The resource allocation of Message 2 is
`addressed With an identity RA-RNTI that is associated With
`the frequency and time resources of a PRACH, but is common
`for different preamble sequences. The Message 2 contains
`UL allocations for the transmissions of a Message 3 in the UL
`(e.g., step 3 of the Contention Based Random Access Proce
`dure at FIG. 1B).
`RACH preambles are transmitted by the UEs using a full
`path-loss compensation PC formula. The target is that recep
`tion RX level of those preambles at the eNB is the same, and
`so independent of path-loss. This is needed because several
`simultaneous preamble transmissions can take place in the
`same PRACH resource and in order to detect them, their
`poWer at the eNB needs to be roughly the same to avoid the
`Well-known near-far problem for spread spectrum transmis
`sions. HoWever subsequent uplink transmissions on the
`PUSCH are orthogonal, and so called fractional poWer con
`trol can be used. This alloWs higher transmit TX poWers for
`UEs that are near the eNB because interference that those UEs
`generate to neighbor cells is small as compared to cell edge
`UEs. This method alloWs higher average uplink bit rates on
`the PUSCH.
`In general, the eNB does not knoW What is the path-loss
`value used by the UE in its full PL compensation PC formula
`used for the UE’s RACH message. In the case of a UE being
`handed-over from another eNB, an estimate of the path-loss
`value could be provided to the target cell/eNB based on UE
`measurement reports sent to the serving eNB prior to the
`handover. HoWever, for an initial access or for UL or DL data
`arrival this is not possible since there is no handover. Because
`of this, the eNB does not knoW the poWer difference betWeen
`the UE’s RACH preamble transmission and the UE’s trans
`mission using the PUSCH poWer formula.
`It has been agreed that Message 2 contains a poWer control
`command for transmission of Message 3, but the de?nition
`and objective of that command is not yet speci?ed. Therefore
`
`Page 8 of 15
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`US 8,385,966 B2
`
`3
`the eNB does not have su?icient information to give a correct
`poWer control command in response to the UE’s RACH mes
`sage. The result then, and as mentioned above, is that the
`poWer that the UE uses for transmission of Message 3 is not
`knoWn to the eNB if the UE uses the PUSCH PC formula for
`sending Message 3.
`The problem therefore may be stated as hoW best to de?ne
`a transition from the full path loss compensated preamble
`transmission to the PUSCH (fractional) poWer control sys
`tem.
`
`SUMMARY
`
`In accordance With an exemplary embodiment of the inven
`tion is a method that comprises using a processor to initialiZe
`for i:0 a ?rst poWer control adjustment state g(0) for an
`uplink control channel and a second poWer control adjust
`ment state f(i) for an uplink shared channel to each re?ect an
`open loop poWer control error; using the processor to com
`pute an initial transmit poWer for the uplink shared channel
`using full pathloss compensation, Wherein the initial transmit
`poWer depends on a preamble poWer of a ?rst message sent on
`an access channel, and is initialiZed With the second poWer
`control adjustment state f(0); and sending from a transmitter
`a third message on the uplink shared channel at the initial
`transmit poWer.
`In accordance With an exemplary embodiment of the inven
`tion is a computer readable memory storing a computer pro
`gram that When executed by a processor results in actions. In
`this embodiment the actions comprise: initialiZing for i:0 a
`?rst poWer control adjustment state g(0) for an uplink control
`channel and a second poWer control adjustment state f(i) for
`an uplink shared channel to each re?ect an open loop poWer
`control error; computing an initial transmit poWer for the
`uplink shared channel using full pathloss compensation,
`Wherein the initial transmit poWer depends on a preamble
`poWer of a ?rst message sent on an access channel, and is
`initialiZed With the second poWer control adjustment state
`f(0); and outputting the initial transmit poWer for transmis
`sion of a third message on the uplink shared channel.
`In accordance With an exemplary embodiment of the inven
`tion is an apparatus Which comprises at least a processor and
`a transmitter. The processor is con?gured to initialiZe, for i:0,
`a ?rst poWer control adjustment state g(0) for an uplink con
`trol channel and a second poWer control adjustment state f(i)
`for an uplink shared channel to each re?ect an open loop
`poWer control error, and con?gured to compute an initial
`transmit poWer for the uplink shared channel using full path
`loss compensation, in Which the initial transmit poWer
`depends on a preamble poWer of a ?rst message sent on an
`access channel, and the initial poWer is initialiZed With the
`second poWer control adjustment state f(0). The transmitter is
`con?gured to send a third message on the uplink shared
`channel at the initial transmit poWer.
`These and other aspects of the invention are detailed With
`particularity beloW.
`
`20
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`
`40
`
`45
`
`50
`
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`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`60
`
`The foregoing and other aspects of the exemplary embodi
`ments of this invention are made more evident in the folloW
`ing Detailed Description, When read in conjunction With the
`attached DraWing Figures.
`FIG. 1A reproduces FIG. 4-1 of 3GPP TS 36.300, and
`shoWs the overall architecture of the E-UTRAN system.
`
`65
`
`4
`FIGS. 1B and 1C respectively reproduce FIGS. 10.1.5.1-1
`and 10.1.5.1-2 of 3GPP TS 36.300 v8.4.0, Contention Based
`Random Access Procedure and Non-Contention Based Ran
`dom Access Procedure.
`FIG. 2 shoWs a simpli?ed block diagram of various elec
`tronic devices that are suitable for use in practicing the exem
`plary embodiments of this invention.
`FIGS. 3-4 are logical ?oW diagrams that illustrate the
`operation of methods, and the result of execution of computer
`programs instructions by the data processor such as that
`shoWn in FIG. 2 according to various speci?c embodiments of
`the invention.
`
`DETAILED DESCRIPTION
`
`In the speci?c examples given beloW, the problem solved
`by those embodiments is hoW the poWer control formulas for
`PUSCH and PUCCH are taken in use during or after the
`Random Access procedure.
`To the inventors’ knowledge this problem has not been
`solved before. Operation according to 3GPP TS 36.213
`v.8.2.0 (attached to the priority document as Exhibit B) is that
`Message 3 (see FIG. 1B) is transmitted using the PUSCH PC
`formula taking into account the PC command received from
`the eNB in Message 2 (see FIGS. 1B and 1C). HoWever, this
`does not specify hoW the UE speci?c parameters of the
`PUSCH and PUCCH poWer control formulas are initialiZed.
`The PUSCH PC formula for the UE in the Ah subframe is
`de?ned at section 5.1.1.1 of 3GPP TS 36.213 v8.2.0 as fol
`loWs:
`
`[1]
`
`PPUSCH(i):min{PMAX>10 lOglO(MPUSCH(i))+
`POJUSCHU)+OLIPL+ATF(TF(i))+?i)}(dBm);
`Where,
`P M AX is the maximum alloWed poWer that depends on the
`UE poWer class
`MPUSCH(i) is the siZe of the PUSCH resource assignment
`expressed in number of resource blocks valid for sub
`frame i.
`POiPUSCHQ) is a parameter composed of the sum of a 8-bit
`cell speci?c nominal component P OiNO MINA Li P USC H (j)
`signalled from higher layers for j:0 and 1 in the range of
`[—126, 24] dBm With 1 dB resolution and a 4-bit UE
`speci?c component POiUEiPUSCH (i) con?gured by
`RRC for j:0 and 1 in the range of [—8, 7] dB With 1 dB
`resolution. For PUSCH (re)transmissions correspond
`ing to a con?gured scheduling grant then j:0 and for
`PUSCH (re)transmissions corresponding to a received
`PDCCH With DCI format 0 associated With a neW packet
`transmission then j:1.
`(X€{0, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1} is a 3-bit cell speci?c
`parameter provided by higher layers
`PL is the doWnlink pathloss estimate calculated in the UE
`ATF(TF(i)):10 loglO(2MPR'KS—1) for KS:1.25 and 0 for
`KSIO Where Ksis a cell speci?c parameter given by RRC
`TF(i) is the PUSCH transport format valid for subframe
`1
`MPR:modulation><coding rateININFO/NRE Where
`NINFO are the number of information bits and NRE is
`the number of resource elements determined from
`TF(i) and MPUSCH (i) for subframe i
`BPUSCHis a UE speci?c correction value, also referred to as
`a TPC command and is included in PDCCH With DCI
`format 0 or jointly coded With other TPC commands in
`PDCCH With DCI format 3/3A. The current PUSCH
`poWer control adjustment state is given by f(i) Which is
`de?ned by:
`
`Page 9 of 15
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`US 8,385,966 B2
`
`5
`f(i):f(i-1)+6PUSCH(i-KPUSCH) if f(*) represents accu
`mulation
`Where f(0):0 and KPUSCHI4
`The UE attempts to decode a PDCCH of DCI format
`0 and a PDCCH of DCI format 3/ 3A in every sub
`frame except When in DRX
`6PUSCHIO dB for a subframe Where no TPC command
`is decoded or Where DRX occurs.
`The 6PUSCH dB accumulated values signalled on
`PDCCH With DCI format 0 are [-1, 0, 1, 3].
`The 6PUSCH dB accumulated values signalled on
`PDCCH With DCI format 3/ 3A are one of [-1, 1] or
`[-1, 0, 1, 3] as semi-statically con?gured by higher
`layers.
`If UE has reached maximum poWer, positive TPC
`commands are not accumulated
`If UE has reached minimum poWer, negative TPC
`commands shall not be accumulated
`UE shall reset accumulation
`at cell-change
`When entering/leaving RRC active state
`When an absolute TPC command is received
`When POiUEiPUSCH (j) is received
`When the UE (re)synchroniZes
`f(i):6PUSCH(i-KPUSCH) if f(*) represents current abso
`lute value
`Where zspUscHn-xwsm) Was signalled on PDCCH
`With DCI format 0 on subframe i-KPUSCH
`Where KPUSCHI4
`The 6PUSCH dB absolute values signalled on PDCCH
`With DCI format 0 are [-4, -1, 1, 4].
`f(i):f(i— 1) for a subframe Where no PDCCH With DCl
`format 0 is decoded or Where DRX occurs.
`f(*) type (accumulation or current absolute) is a UE
`speci?c parameter that is given by RRC.
`The PUCCH PC formula for the UE in the ith subframe is
`de?ned at section 5.1.2.1 of 3GPP TS 36.213 v8.2.0 as fol
`loWs:
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`Where
`ATFiPUCCHGF) table entries for each PUCCH transport
`format (TF) de?ned in Table 5.4-1 in [3] are given by
`RRC
`Each signalled ATFiPUCCHGF) 2-bit value corresponds
`to a TF relative to PUCCH DCI format 0.
`POiPUCCH is a parameter composed of the sum of a 5-bit
`cell speci?c parameter P OiNO MIN A Li PUCCH provided by
`higher layers With 1 dB resolution in the range of [-127,
`-96] dBm and a UE speci?c component POiUEiPUCCH
`con?gured by RRC in the range of [-8, 7] dB With 1 dB
`resolution.
`opUccHis a UE speci?c correction value, also referred to as
`a TPC command, included in a PDCCH With DCI format
`1A/1/2 or sent jointly coded With other UE speci?c
`PUCCH correction values on a PDCCH With DCI for
`mat 3/ 3A.
`The UE attempts to decode a PDCCH With DCI format
`3/3A and a PDCCH With DCI format 1A/ 1/2 on every
`subframe except When in DRX.
`6PUCCH from a PDCCH With DCI format 1A/1/2 over
`rides that from a PDCCH With DCI format 3/3A When
`both are decoded in a given subframe.
`GPUCCHIO dB for a subframe Where no PDCCH With
`DCI format 1A1/2/3/3A is decoded or Where DRX
`occurs.
`
`50
`
`55
`
`60
`
`65
`
`6
`g(i):g(i-1)+APUCCH(i-KPUCCH) Where g(i) is the cur
`rent PUCCH poWer control adjustment state With ini
`tial condition g(0):0.
`The 6PUCCH dB values signalled on PDCCH With DCI
`format 1A/1/2 are [-1, 0, 1,3].
`The 6PUCCH dB values signalled on PDCCH With DCI
`format 3/3A are [-1, 1] or [-1, 0, 1, 3] as semi
`statically con?gured by higher layers.
`If UE has reached maximum poWer, positive TPC
`commands are not accumulated
`If UE has reached minimum poWer, negative TPC
`commands shall not be accumulated
`UE shall reset accumulation
`at cell-change
`When entering/leaving RRC active state
`When POiUEiPUCCHQ) is received
`When the UE (re)synchroniZes
`The preamble PC formula for the UE’s transmission on the
`RACH is:
`
`[3]
`
`Where
`Ptmget is the broadcasted target poWer;
`PL is the path loss that UE estimates from DL; and
`APmmPMP is the poWer ramp-up applied for preamble
`retransmissions.
`As can be seen above at equation [1], the formula for
`PPUSCH (i) depends on the current PUSCH poWer control
`adjustment state Which is termed f(i). For accumulation, this
`adjustment state depends on previous adjustments made in
`previous subframes, even for the case Where f(i) is set to an
`absolute value since it is set for the subframe (i-KPUSCH).
`When the UE ?rst sends data on the PUSCH, there is no
`previous subframe and so iIO, Which is addressed in 3GPP TS
`36.213 v8.2.0 as Zeroing out the entire term so that f(0):0.
`Further, While it is true that the UE is to reset its accumulation
`Whenever it
`receives
`a neW UE-speci?c portion
`POiUEiPUSCHQ) of the POiPUSCHQ) (and similarly for
`POiPUCCH), after a RACH access the UE has received no
`UE-speci?c portion and so it lacks that parameter to reset
`according to 3GPP TS 36.213.
`Also, at equation [2] the poWer control formula for the
`PUCCH PPUCCHG) depends on the current PUCCH poWer
`control adjustment state Which is termed g(i) and Which also
`depends on previous adjustments made in previous PUCCH
`subframes. When the UE ?rst sends a message on the
`PUCCH, there is no previous subframe and so iIO, Which is
`similarly addressed in 3GPP TS 36.213 v8.2.0 as Zeroing out
`the entire term so that g(0):0.
`Consider the case for contention-less random access such
`as that shoWn at FIG. 1C, Where the UE transmits preambles
`that are dedicated for that UE. The embodiments of the inven
`tion described for contention-less random access may also be
`used for contention based random access When it is consid
`ered that collisions Will be infrequent enough in the conten
`tion-based system so as not to substantially affect operation in
`the cell.
`According to an embodiment of the invention, the UE
`receives a poWer control command (e.g., APPC) in the pre
`amble response from the eNB, Which is Message 2. The UE
`then initiates the PC formula for PUSCH and PUCCH, or
`compensates open loop error, according to the folloWing
`equations:
`
`POiUEJUCCH'l'ga)):APPC+APrampup
`
`[4b]
`
`Page 10 of 15
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`US 8,385,966 B2
`
`7
`These equations say that the sum of the UE speci?c power
`control constants (POiUEiPUSCH or POiUEiPUCCH) and the
`poWer control initial states (f(0) or g(0)) is equal to the open
`loop poWer control error, taking into account the preamble
`poWer ramp-up. APPC is here assumed to be the difference
`betWeen the target preamble poWer and the poWer that eNB
`actually observes. The actual value of APPC may be signalled
`directly by the eNB as the poWer control command, or to save
`on signalling overhead the eNB may explicitly signal a bit
`sequence (one, tWo or more bits) as the poWer control com
`mand Which the receiving UE uses as an index to look up the
`true value APPC that is associated in a locally stored table With
`that index.
`There are several options for dividing the correction
`betWeen the UE speci?c constants and the poWer control
`states. For example, in a ?rst option the UE speci?c poWer
`control terms POiUEiPUSCH and POiUEiPUCCH could be ini
`tialiZed to Zero and the Whole correction is covered by f(0) or
`g(0). In this case then equations 4a and 4b Would read f(0):g
`(0):APPC+APmmPuP for initiating the closed loop correction
`values for PUCCH and PUSCH. This can be alWays done as
`far as the poWer control state f is accumulated. (According to
`current 3GPP agreements g is alWays accumulating.) HoW
`ever, if f is modi?ed With absolute PC commands, its dynamic
`range is limited and may not cover the Whole open loop
`correction APPC+APmmPuP. If this happens, the part of the
`correction that cannot be included in f(0) could be taken into
`account by adjusting POiUEiPUSCH. As another example, a
`second option is to take the open loop error into account
`adjusting principally the UE speci?c poWer control terms
`POiUEiPUSCH and POiUEiPUCCH. These parameters have a
`limited range and the part of the open loop error that cannot be
`compensated by adjusting these UE speci?c constants could
`be covered by initialiZing the poWer control states f(0) or g(0)
`to a nonZero value. The bene?t of the ?rst option is that the
`eNB Would knoW the UE speci?c constants POiUEiPUSCH
`and POiUEiPUCCH (at least When f is accumulating), Which
`might make later adjustments of these constants easier. HoW
`ever, the second option could be more natural because the
`purpose of the UE speci?c constants is mainly to compensate
`systematic errors in the PL determination and IX poWer
`setting and these are already visible as an error in the open
`loop poWer control of the preambles. Of course, the above tWo
`options are presented only as non-limiting examples and this
`aspect of the invention is not limited to only those tWo.
`For the case of a dedicated preamble such as is shoWn at
`FIG. 1C or When the preamble collisions of a contention
`based system are otherWise infrequent, the poWer for Mes
`sage 3 may be generated by using the PUSCH PC formula
`directly according to the above explained embodiment of the
`invention. This may lead to UE transmit TX poWer that is
`unnecessarily high, but the inventors do not see this as a
`problem.
`The inventors have determined that a problem could arise
`in the above explained procedure, speci?cally Where tWo UEs
`transmit the same preamble sequence and use fractional PL
`compensation for Message 3. The problem appears most pro
`nounced When the preamble of a UE With a large PL is
`received at the eNB stronger than the preamble of another UE
`With small PL. The fractional PC could result in Message 3 of
`the UE With the smaller PL being received at the eNB With a
`stronger signal strength than the Message 3 of the UE With the
`larger PL. This Would of course make detection by the eNB of
`the Weaker Message 3 less likely, despite the fact that in the
`above scenario the Weaker Message 3 is from the UE Who has
`received correct timing advance. Decoding of the stronger
`Message 3 is likely to fail because the timing advance of a
`
`40
`
`45
`
`20
`
`25
`
`30
`
`35
`
`50
`
`55
`
`60
`
`65
`
`8
`Wrong UE has been used When transmitting it. Further, if the
`timing advance for Message 3 transmissions are set based on
`the preamble of the UE With the larger PL, then the UE With
`the smaller PL Would use a large poWer and the Wrong TA
`value When transmitting its Message 3, and thereby generate
`interference to other transmissions.
`To achieve improved performance When the UE performs
`contention based random access and When preamble colli
`sions are assumed to be frequent, another embodiment of the
`invention de?nes the Message 3 poWer relative to preamble
`poWer, i.e. full path loss compensation used. The objective is
`that transmit TX poWer of Message 3 Would not be unneces
`sary high. In one particular embodiment, this objective can be
`realiZed by using the folloWing formula:
`
`PMSg3 :Ppream ble+AO,preambleiMsg3 +APCiMsg3+1 0
`loglO(MPUSCH(i))+ATF(TF(i))'
`[5]
`The terms MPUSCH (i) and ATF(TF(i)) in equation [5] are
`the same terms as in equation [1]. Like equation [1], PMSg3 is
`the minimum of P MAX and the above summation, but PMAX is
`not explicitly shoWn at equation [5]. Note that ATF(TF(i)) is
`calculated at the UE from signalling the UE receives (e.g., 0t
`and KS), and that for the case Where (Fl full path loss com
`pensation is used in this Message 3 poWer, just as for the
`preamble poWer. Different from equation [1] is the equation
`[5] term A0,lwmmbhdwsg3 Which corresponds to