US008331328B2
`
`
`(12) United States Patent
`
`Papasakellariou et a1.
`
`
`(10) Patent N0.:
`
`(45) Date of Patent:
`
`
`US 8,331,328 B2
`
`Dec. 11, 2012
`
`
`(54) CONTROL AND DATA SIGNALING IN
`
`SC-FDMA COMMUNICATION SYSTEMS
`
`
`(75) Inventors: Aris Papasakellariou, Dallas, TX (US);
`
`Joon-Young Cho, SuWon-si (KR)
`
`
`(73) Assignee: Samsung Electronic Co., Ltd (KR)
`
`
`(*) Notice:
`
`Subject to any disclaimer, the term of this
`
`patent is extended or adjusted under 35
`
`U.S.C. 154(b) by 1059 days.
`
`
`(21) App1.No.: 12/133,120
`
`
`(22) Filed:
`
`Jun. 4, 2008
`
`
`(65)
`
`Prior Publication Data
`
`
`US 2008/0304467 A1
`
`Dec. 11, 2008
`
`
`Related US. Application Data
`
`(60) Provisional application No. 60/942,843, ?led on Jun.
`
`8, 2007.
`
`
`(51) Int. Cl.
`
`(2006.01)
`
`H04B 7/216
`(2006.01)
`
`H04B 7/208
`(52) US. Cl. ...................................... .. 370/335; 370/344
`
`(58) Field of Classi?cation Search ................. .. 370/344
`
`See application ?le for complete search history.
`
`
`(56)
`
`References Cited
`
`
`U.S. PATENT DOCUMENTS
`
`6,901,046 B2
`5/2005 Hsu et a1.
`
`2005/0232138 A1 10/2005 Byun et a1.
`
`
`2007/0014272 A1* 1/2007
`
`2007/0097981 A1 *
`5/2007
`
`2007/0171849 A1* 7/2007
`
`2007/0195740 A1* 8/2007
`
`2007/0297386 A1* 12/2007
`
`2008/0075060 A1* 3/2008
`
`2008/0219235 A1* 9/2008
`
`2008/0232300 A1* 9/2008
`
`
`Palanki et a1. .............. .. 370/344
`
`Papasakellariou .
`370/394
`
`Zhang et a1. ......... ..
`370/310
`
`Bhushan et a1.
`370/335
`
`Zhang et a1. ..... ..
`370/344
`
`Tiirola et a1. ..
`370/344
`
`Ma et a1. .......... ..
`370/344
`
`McCoy et a1. .............. .. 370/328
`
`
`FOREIGN PATENT DOCUMENTS
`
`101390323
`3/2009
`
`CN
`1 646 163
`4/2006
`
`EP
`1020040063324
`7/2004
`
`KR
`* cited by examiner
`
`
`Primary Examiner * John Blanton
`
`(74) Attorney, Agent, or Firm * The Farrell LaW Firm, PC.
`
`
`ABSTRACT
`
`(57)
`Apparatus and method for multiplexing control information
`
`bits and data information bits into sub-frame symbols
`
`depending on the location of symbols carrying a reference
`
`signal (RS), to provide an estimate for the channel medium
`
`and enable coherent demodulation for signals carrying infor
`
`mation bits. The control information bits include ACK or
`
`NAK and/or channel CQI bits. The ACK/NAK bits are placed
`
`With priority in symbols around the symbols carrying the RS,
`
`to alloW for improved accuracy of the channel estimate, fol
`
`loWed by the CQI bits When both ACK/NAK and CQI bits
`
`exist. Moreover, the sub-frame resources required to achieve
`
`the desired reception reliability for the control information
`
`depend on the operating conditions and can varied to mini
`
`miZe the associated control overhead.
`
`
`14 Claims, 10 Drawing Sheets
`
`
`| ACK/NAK
`
`
`C01 1620)
`
`ACK]NAK [61 0)
`
`MA‘ DATAT DATA
`
`
`63
`
`I
`
`DATAW DATA 1011A
`
`
`ONE SUB-FRAME
`
`
`

`

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`

`US 8,331,328 B2
`
`
`1
`
`CONTROL AND DATA SIGNALING IN
`
`SC-FDMA COMMUNICATION SYSTEMS
`
`
`PRIORITY
`
`
`The present Application for Patent claims priority to US.
`
`Provisional Application No. 60/942,843 entitled “Control
`
`and Data Signaling in SC-FDMA Communication Systems”
`
`?led Jun. 8, 2007, the contents of Which is incorporated by
`
`reference herein.
`
`
`BACKGROUND OF THE INVENTION
`
`
`20
`
`
`1. Field of the Invention
`
`The present invention is directed, in general, to Wireless
`
`communication systems and, more speci?cally, to multiplex
`
`ing control and data information in single-carrier frequency
`
`division multiple access (SC-FDMA) communication sys
`
`tems.
`
`2. Description of the Related Art
`In particular, the present invention considers the transmis
`
`sion of positive or negative acknowledgement bits (ACK or
`
`NAK, respectively) and channel quality indicator (CQI) bits
`
`together With data information bits in an SC-FDMA commu
`
`nications system and is further considered in the development 25
`
`of the 3rd Generation Partnership Project (3GPP) Evolved
`
`Universal Terrestrial Radio Access (E-UTRA) long term evo
`
`lution (LTE). The invention assumes the uplink (UL) com
`
`munication corresponding to the signal transmission from
`
`mobile user equipments (UEs) to a serving base station (Node 30
`
`B).A UE, also commonly referred to as a terminal or a mobile
`
`station, may be ?xed or mobile and may be a Wireless device,
`
`a cellular phone, a personal computer device, a Wireless
`
`modem card, etc. A Node B is generally a ?xed station and
`
`may also be called a base transceiver system (BTS), an access 35
`
`point, or some other terminology. The ACK/NAK bits and
`
`CQI bits may also be referred to simply as control information
`
`bits.
`
`The ACK or NAK bits are in response to the correct or
`
`incorrect, respectively, data packet reception in the doWnlink 40
`
`(DL) of the communication system, Which corresponds to
`
`signal transmission from the serving Node B to a UE. The
`
`CQI transmitted from a reference UE is intended to inform the
`
`serving Node B ofthe channel conditions the UE experiences
`
`for signal reception, enabling the Node B to perform channel 45
`
`dependent scheduling of DL data packets. Either or both of
`
`the ACK/NAK and CQI may be transmitted by a UE in the
`
`same transmission time interval (TTI) With data or in a sepa
`
`rate TTI With no data. The disclosed invention considers the
`
`former case, Which may also be referred to as data-associated 50
`
`transmission of the ACK/NAK and/or CQI.
`
`The UEs are assumed to transmit control and data bits over
`
`a TTI corresponding to a sub-frame. FIG. 1 illustrates a block
`
`diagram ofthe sub -frame structure 110 assumed in the exem
`
`plary embodiment of the disclosed invention. The sub-frame 55
`
`includes tWo slots. Each slot 120 further includes seven sym
`
`bols and each symbol 130 further includes of a cyclic pre?x
`
`(CP) for mitigating interference due to channel propagation
`
`effects, as it is knoWn in the art. The signal transmission in the
`
`tWo slots may be in the same part or it may be at tWo different 60
`
`parts of the operating bandWidth. Furthermore, the middle
`
`symbol in each slot carries the transmission of reference
`
`signals (RS) 140, also knoWn as pilot signals, Which are used
`
`for several purposes including for providing channel estima
`
`tion for coherent demodulation of the received signal.
`The transmission bandWidth (BW) is assumed to include
`
`frequency resource units, Which Will be referred to herein as
`
`
`65
`
`
`2
`
`resource blocks (RBs). An exemplary embodiment assumes
`
`that each RB includes 12 sub-carriers and UEs are allocated a
`
`multiple N of consecutive RBs 150. Nevertheless, the above
`
`values are only illustrative and not restrictive to the invention.
`
`An exemplary block diagram of the transmitter functions
`
`for SC-FDMA signaling is illustrated in FIG. 2. Coded CQI
`
`bits 205 and coded data bits 210 are multiplexed 220. If
`
`ACK/NAK bits also need to be multiplexed, the exemplary
`
`embodiment assumes that data bits are punctured to accom
`
`modate ACK/NAK bits 230. Alternatively, CQI bits (if any)
`
`may be punctured or different rate matching, as it is knoWn in
`
`the art, may apply to data bits or CQI bits to accommodate
`
`ACK/NAK bits. The discrete Fourier transform (DFT) of the
`
`combined data bits and control bits is then obtained 240, the
`
`sub-carriers 250 corresponding to the assigned transmission
`
`bandWidth are selected 255, the inverse fast Fourier transform
`
`(IFFT) is performed 260 and ?nally the cyclic pre?x (CP) 270
`
`and ?ltering 280 are applied to the transmitted signal 290.
`
`Alternatively, as illustrated in FIG. 3, in order to transmit
`
`the control (ACK/NAK and/or CQI) bits 310, puncturing of
`
`coded data bits 320 may apply 330 (instead of also applying
`
`rate matching as in FIG. 2) and certain coded data bits (for
`
`example, the parity bits in case of turbo coding) may be
`
`replaced by control bits. The discrete Fourier transform
`
`(DFT) 340 of the combined bits is then obtained, the sub
`
`carriers 350 corresponding to the assigned transmission
`
`bandWidth are selected 355 (localiZed mapping is assumed
`
`but distributed mapping may also be used), the inverse fast
`
`Fourier transform (IFFT) 360 is performed and ?nally the
`
`cyclic pre?x (CP) 370 and ?ltering 380 are applied to the
`
`transmitted signal 390.
`
`This time division multiplexing (TDM) illustrated in FIG.
`
`2 and FIG. 3 betWeen control (ACK/NAK and/or CQI) bits
`
`and data bits prior to the DFT is necessary to preserve the
`
`single carrier property ofthe transmission. Zero padding, as it
`
`is knoWn in the art, is assumed to be inserted by a reference
`
`UE in sub-carriers used by another UE and in guard sub
`
`carriers (not shoWn). Moreover, for brevity, additional trans
`
`mitter circuitry such as digital-to-analog converter, analog
`
`?lters, ampli?ers, and transmitter antennas are not illustrated
`
`in FIG. 2 and FIG. 3. Similarly, the encoding process for the
`
`data bits and the CQI bits, as Well as the modulation process
`
`for all transmitted bits, are Well knoWn in the art and are
`
`omitted for brevity.
`
`At the receiver, the inverse (complementary) transmitter
`
`operations are performed. This is conceptually illustrated in
`
`FIG. 4 Where the reverse operations of those illustrated in
`
`FIG. 2 are performed. As it is knoWn in the art (not shoWn for
`
`brevity), an antenna receives the radio -frequency (RF) analog
`
`signal and after further processing units (such as ?lters,
`
`ampli?ers, frequency doWn-converters, and analog-to-digital
`
`converters) the digital received signal 410 passes through a
`
`time WindoWing unit 420 and the CP is removed 430. Subse
`
`quently, the receiver unit applies an FFT 440, selects 445 the
`
`sub-carriers 450 used by the transmitter, applies an inverse
`
`DFT (IDFT) 460, extracts the ACK/NAK bits and places
`
`respective erasures for the data bits 470, and de-multiplexes
`
`480 the data bits 490 and CQI bits 495. As for the transmitter,
`
`Well knoWn in the art receiver functionalities such as channel
`
`estimation, demodulation, and decoding are not shoWn for
`
`brevity and they are not material to the present invention.
`
`The control bits typically require better reception reliabil
`
`ity than the data bits. This is primarily because hybrid-auto
`
`matic-repeat-request (HARQ) usually applies to data trans
`
`mission but not to control transmission. Additionally, ACK/
`
`NAK bits typically require better reception reliability that
`
`CQI bits as erroneous reception of ACK/NAK bits has more
`
`
`

`

`US 8,331,328 B2
`
`
`3
`detrimental consequences to the overall quality and e?iciency
`
`of communication than does erroneous reception for the CQI
`
`bits.
`
`The siZe of resources in a transmission sub-frame required
`
`for control signaling for a given desired reception reliability
`
`depend on the channel conditions the signal transmission
`
`from a UE experiences and in particular, on the signal-to
`
`interference and noise ratio (SINR) of the received signal at
`
`the serving Node B.
`
`There is a need to determine the placement of control bits
`
`when transmitted in the same sub -frame with data bits so that
`
`better reception reliability is provided for the control bits than
`
`for the data bits.
`
`There is another need to determine the placement of
`
`acknowledgement bits relative to channel quality indication
`
`bits, in case they are simultaneously multiplexed, in order to
`
`provide better reception reliability for the former.
`
`There is another need to dimension the resources required
`
`for the transmission of acknowledgement bits, in a sub-frame
`
`also containing data bits, as a function of the channel condi 20
`
`tions experienced by the signal transmission from a UE.
`
`
`SUMMARY OF THE INVENTION
`
`
`4
`
`FIG. 6 is a block diagram illustrating a ?rst method for the
`
`selection ofthe sub-frame symbols carrying the transmission
`
`of CQI bits and ACK/NAK bits;
`
`FIG. 7 is a block diagram illustrating a ?rst method for the
`
`selection ofthe sub-frame symbols carrying the transmission
`
`ofACK/NAK bits;
`
`FIG. 8 is a block diagram illustrating a ?rst method for the
`
`selection ofthe sub-frame symbols carrying the transmission
`
`of CQI bits;
`
`FIG. 9 is a block diagram illustrating a second method for
`
`the selection ofthe sub-frame symbols carrying the transmis
`
`sion ofACK/NAK bits with reduced overhead; and
`
`FIG. 10 is a block diagram illustrating a second method for
`
`the selection ofthe sub-frame symbols carrying the transmis
`
`sion CQI bits and ACK/NAK bits.
`
`
`DETAILED DESCRIPTION OF THE
`
`EXEMPLARY EMBODIMENTS
`
`
`The present invention now will be described more fully
`
`hereinafter with reference to the accompanying drawings.
`
`This invention may, however, be embodied in many different
`
`forms and should not be construed as limited to the embodi
`
`ments set forth herein. Rather, these embodiments are pro
`
`vided so that this disclosure will be thorough and complete,
`
`and will fully convey the scope of the invention to those
`
`skilled in the art.
`
`Additionally, although the invention assumes a single-car
`
`rier frequency division multiple access (SC-FDMA) commu
`
`nication system, it also applies to all FDM systems in general
`
`and to OFDMA, OFDM, FDMA, DPT-spread OFDM, DFT
`
`spread OFDMA, single-carrier OFDMA (SC-OFDMA), and
`
`single-carrier OFDM in particular.
`
`Basically, the system and methods of the embodiments of
`
`the present invention solve problems related to the need for
`
`providing the desired reliability for the reception of control
`
`signaling under indicative transmission sub-frame structures
`
`and provide additional advantages such as the reduction of
`
`resource overhead for the transmission of control signals.
`
`A ?rst observation for the sub -frame structure illustrated in
`
`FIG. 1 is that the reference signal (RS) exists only in the
`
`middle symbol of each slot. In case of a mobile terminal, or
`
`user equipment (UE), with high speed, this can substantially
`
`degraded channel estimation for symbols located further
`
`away from the RS (that is, for symbols near the beginning and
`
`end of each slot) due to the faster variation of the channel
`
`medium as the UE velocity increases. This may be acceptable
`
`for data transmission that is coded, which has typically a
`
`relatively large target block error rate (BLER), such as 10% or
`
`above, and can bene?t from retransmissions though a con
`
`ventional HARQ process. Conversely, the CQI and particu
`
`larly the ACK/NAK have much stricter performance require
`
`ments, HARQ typically does not apply to the corresponding
`
`transmissions, and providing an accurate channel estimate is
`
`essential in achieving the desired reception reliability.
`
`A brief set of simulation results for the un-coded (raw) bit
`
`error rate (BER) is provided to illustrate the impact of inac
`
`curate channel estimation on the reception quality as a func
`
`tion ofthe symbol position in the slot and the UE speed. Table
`
`I provides the simulation setup under optimistic conditions
`
`for the performance loss due to imperfect channel estimation
`
`at symbols further away from the RS for the following rea
`
`sons:
`
`Transmission bandwidth is 1 RB. This maximizes power
`
`per sub-carrier.
`
`Channel frequency selectivity is large and there are 2
`
`uncorrelated Node B receiver antennas. This maximizes
`
`
`Accordingly, the present invention has been designed to 25
`
`solve the above-mentioned problems occurring in the prior
`
`art, and embodiments of the invention provide an apparatus
`
`and a method for allocating resources in a sub-frame for the
`
`transmission of control bits and data bits.
`
`In accordance with an embodiment of the present inven 30
`
`tion, provided are an apparatus and method for the placement
`
`of signals carrying the control bits and data bits in transmis
`
`sion symbols relative to the symbols used for transmission of
`
`reference signals in order to enable better reception reliability
`
`of the control bits.
`Another embodiment of the present invention provides an
`
`apparatus and method for the placement ofacknowledgement
`
`bits with higher priority than channel quality indication bits to
`
`enable better reception reliability of the acknowledgement
`
`bits.
`Another embodiment of the present invention provides an
`
`apparatus and method for dimensioning and placing
`
`acknowledgement bits in a sub-frame according to the corre
`
`sponding resources needed to achieve desired reception reli
`
`ability.
`
`40
`
`
`45
`
`
`35
`
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`
`The above and other aspects, features, and advantages of
`
`the present invention will be more apparent from the follow 50
`
`ing detailed description taken in conjunction with the accom
`
`panying drawings, in which:
`
`FIG. 1 is a block diagram illustrating an exemplary sub
`
`frame structure for the SC-FDMA communication system;
`
`FIG. 2 is a block diagram illustrative of a ?rst exemplary 55
`
`SC-FDMA transmitter for multiplexing data bits, CQI bits,
`
`and ACK/NAK bits in a transmission sub-frame;
`
`FIG. 3 is another block diagram illustrative of a second
`
`exemplary SC-FDMA transmitter or multiplexing data bits,
`
`CQI bits, and ACK/NAK bits in a transmission sub-frame;
`FIG. 4 is a block diagram illustrative of an exemplary
`
`SC-FDMA receiver, corresponding to the ?rst exemplary SC
`
`FDMA transmitter, for de-multiplexing data bits, CQI bits,
`
`and ACK/NAK bits in a reception sub-frame;
`
`FIG. 5 presents un-coded bit error rate (BER) results as a 65
`
`function of the symbol number (symbol position) in the sub
`
`frame slot and the UE velocity;
`
`
`60
`
`
`

`

`US 8,331,328 B2
`
`
`5
`
`the slope of the un-coded (raw) BER curve and mini
`
`miZes the relative performance loss due to imperfect
`
`channel estimation for a target BER value.
`
`Operating signal-to-interference and noise ratio (SINR) is
`
`large. This minimiZes the impact of inaccurate channel
`
`estimation.
`
`
`TABLE 1
`
`
`Simulation Assumptions
`
`
`Parameters
`
`Assumptions
`
`
`Operating Bandwidth @
`Carrier Frequency
`
`Modulation Scheme
`Data Transmission
`Bandwidth (BW)
`
`UE Speed
`
`Transmission Type
`
`Channel Model
`
`Number of Node B Receiver
`Antennas
`
`Number of UE Transmitter
`Antennas
`
`
`5 MHZ @ 2.6 GHZ
`
`
`Quadrature Phase Shift Keying (QPSK)
`
`1 RB
`
`
`3, 30, 120 and 350 Kilometers per hour
`
`(Kmph)
`
`Localized (at same RB) over the sub
`
`frame at 3, 30 Kmph
`
`Frequency Hopping Between Slots at 120
`
`and 350 Kmph
`
`GSM-Terrestrial-Urban with 6 paths
`
`(TU6)
`
`2
`
`
`1
`
`
`FIG. 5 presents the un-coded BER. At symbol locations
`
`symmetric to the RS, the BER is typically the same. At 120
`
`Kmph and 350 Kmph, the transmission in the ?rst slot is
`
`assumed to occur at a different BW than the one in the second
`
`slot (frequency hopped transmission per slot). As only 1 RS
`
`per slot is available for channel estimation, the BER is the
`
`same at symbols symmetric (equidistant) to the RS. At low
`
`speeds, such as 3 Kmph, this is also the case because the
`
`channel does not change over the sub-frame duration. Some
`
`small variability does exist for medium UE speeds, such as 30
`
`Kmph, but, for simplicity, the average BER of symbols equi
`
`distant to the RS is only shown.
`
`Even under the previous optimistic assumptions for the
`
`un-coded (raw) BER degradation due to degraded channel
`
`estimation at symbols further away from the RS, at 350 Kmph
`
`the BER saturates at the 1St/7’h and 2”d/6th symbols. However,
`
`the impact on the BER of the 3’d/5’h symbols is rather con
`
`tained and saturation is avoided (the difference relative to the
`
`BER at 3 Kmph is also partly due to the fact that the latter uses
`
`both RS in the sub -frame for channel estimation which there
`
`fore effectively operates with twice as much SINR). The BER
`
`at 120 Kmph is also degraded by about 3 dB for the 1St/7th
`
`symbols and by about 1.5 dB for the 2”d/6th symbols relative
`
`to the one of the 3’d/5’h symbols at about the 1% point.
`
`Obviously, due to the ?attening of the BER curves for the
`
`lst/7th and 2”d/6’h symbols, the degradation will be much
`
`larger for BER operating points below 1% as it is typically
`
`needed for the NAK reception.
`
`Based on the results in FIG. 5 it becomes apparent that the
`
`control transmission should be placed with priority immedi
`
`ately next to the RS.
`
`FIG. 6 illustrates such a placement when a UE transmits
`
`both ACK/NAK bits 610 and CO1 bits 620 during a sub
`
`frame. These control bits are placed on symbols next to the RS
`
`630 while the data bits 640 are included in symbols transmit
`
`ted over the entire sub-frame (with the obvious exception of
`
`the symbols carrying the RS transmission). Due to the
`
`requirement for better reception reliability, the ACK/NAK
`
`bits are placed closer to the RS than the CO1 bits.
`
`
`6
`
`FIG. 7 illustrates the case in which the UE transmits only
`
`ACK/NAK bits 710 together with data bits 720 during a
`
`sub-frame. The ACK/NAK bits are placed at the two symbols
`
`next to the RS 73 0 in each of the two sub -frame slots while the
`
`01 data bits are included in symbols transmitted over the entire
`
`sub-frame.
`
`FIG. 8 illustrates the case in which the UE transmits only
`
`CQI bits 810 together with data bits 820 during a sub-frame.
`
`The CQI bits are placed at the two symbols next to the RS 830
`
`in each of the two sub-frame slots while the data bits are
`
`included in symbols transmitted over the entire sub-frame.
`
`To minimize channel estimation losses, the ACK/NAK bits
`
`should be placed with priority in the symbol after the ?rst
`
`symbol carrying the RS. This does not impact demodulation
`
`latency as a channel estimate is available only after this ?rst
`
`RS symbol. To address low SINR or coverage issues, the
`
`ACK/NAK bits can also be placed in the symbol before the
`
`second RS. For medium UE speeds, this second placement of
`
`ACK/NAK bits bene?ts from improved channel estimation
`
`20 and time diversity while for high UE speeds, it bene?ts from
`
`frequency and time diversity. This is illustrated in FIG. 9
`
`where the ACK/NAK bits 910 are placed in only one symbol
`
`next to the RS 920 in each slot, these two symbols (one in each
`
`slot) are located between the two RS, while the data bits 930
`
`25 are transmitted throughout the sub-frame (with the obvious
`
`exception of the symbols carrying the RS).
`
`Provisioning for the transmission ofACK/NAK bits in the
`
`sub-carriers over 2 symbols is typically adequate to achieve
`
`the desired BER for the ACK reception. Nevertheless,
`
`30 because the NAK reception has typically a lower BER target,
`
`it is appropriate to have the ACK/NAK transmission over the
`
`number of sub-carriers in 1 symbol in each slot. If further
`
`ACK/NAK transmissions are needed, because of low SINR
`
`or coverage issues, the other symbols next to the RS in the 2
`
`35 slots may also be used as illustrated in FIG. 6 and FIG. 7.
`
`Depending on the number of information bits carried in the
`
`CO1 reporting, which are typically several times more than
`
`the ACK/NAK information hits, the symbols immediately
`
`adjacent to the RS may not su?ice for the CO1 transmission,
`
`40 especially for coverage or SINR limited UEs that are also
`
`typically assigned small bandwidth allocations (a small num
`
`ber of RBs). In such cases, the CO1 transmission may also
`
`extend to one or more symbols that are adjacent to the sym
`
`bols also carrying CQI information that are adjacent to the
`
`45 symbols carrying the RS. An exemplary embodiment of this
`
`principle is illustrated in FIG. 10. As previously discussed,
`
`the location of the ACK/NAK hits 1010 remains in symbols
`
`next to the RS 1030 but the CO1 hits 1020 are located in
`
`symbols throughout the transmission sub-frame, similarly to
`
`50 the data symbols 1040.
`
`While the present invention has been shown and described
`
`with reference to certain exemplary embodiments thereof, it
`
`will be understood by those skilled in the art that various
`
`changes in form and details may be made therein without
`
`55 departing from the spirit and scope ofthe invention as de?ned
`
`by the appended claims.
`
`
`What is claimed is:
`
`1 . An apparatus for receiving a signal in a slot ofa subframe
`
`60 in a wireless communication system, the signal including data
`
`information, and acknowledgement information, the appara
`
`tus comprising:
`
`a receiver for receiving a reference signal that is mapped to
`
`a middle symbol in the slot; and
`
`a de-mapper for de-mapping the acknowledgement infor
`
`mation that is mapped only in ?rst symbols among
`
`remaining symbols in the slot, the reference signal being
`
`
`65
`
`

`

`US 8,331,328 B2
`
`
`7
`
`not mapped to the ?rst symbols, and for de-mapping the
`
`data information that is mapped to the remaining sym
`
`bols,
`
`wherein some ofthe data information is mapped to the ?rst
`
`symbols that are directly adjacent to the middle symbol.
`
`2. The apparatus as in claim 1, wherein said some of the
`
`data information and the acknowledgement information is
`
`respectively received over different subcarriers for transmis
`
`sion of the ?rst symbols.
`
`3. The apparatus as in claim 1, wherein both said some of
`
`the data information and the acknowledgement information is
`
`mapped to the ?rst symbols.
`
`4. An apparatus for transmitting a signal in a slot of a
`
`subframe in a wireless communication system, the signal
`
`including data information, and acknowledgement informa
`
`tion, the apparatus comprising:
`
`a mapper for mapping a reference signal to a middle sym
`
`bol in the slot, mapping the data information in remain
`
`ing symbols in the slot that are not used to map the
`
`reference signal, and mapping the acknowledgement
`
`information only to ?rst symbols among the remaining
`
`symbols in the slot, the ?rst symbols being not used to
`
`map reference signals; and
`
`a transmitter for transmitting the signal including the
`
`mapped reference signal, the mapped data information,
`
`and the mapped acknowledgement information,
`
`wherein some of the data information is located to the ?rst
`
`symbols that are directly adjacent to the middle symbol.
`
`5. The apparatus as in claim 4, wherein the slot consists of
`
`7 symbols, the reference signal is mapped to a 4th symbol
`
`among the 7 symbols, and the acknowledgement information
`
`is mapped only to 3rd and 5th symbols among the 7 symbols.
`
`6. The apparatus as in claim 4, wherein said some of the
`
`data information and the acknowledgement information is
`
`respectively transmitted over different subcarriers for trans
`
`mission of the ?rst symbols.
`
`7. The apparatus as in claim 4, wherein both said some of
`
`the data information and the acknowledgement information is
`
`mapped to the ?rst symbols.
`
`8. A method for transmitting a signal in a slot of a subframe
`
`in a wireless communication system, the signal including data
`
`information, and acknowledgement information, the method
`
`comprising:
`
`mapping a reference signal to a middle symbol in the slot;
`
`mapping the data information to remaining symbols in the
`
`slot not used to map the reference signal;
`
`
`8
`
`mapping the acknowledgement information only to ?rst
`
`symbols among the remaining symbols, the ?rst sym
`
`bols being not used to map reference signals; and
`
`transmitting the signal including the mapped data informa
`
`tion, the mapped acknowledgement information and the
`
`mapped reference signal,
`
`wherein some of the data information is located to the ?rst
`
`symbols that are directly adjacent to the middle symbol.
`
`9. The method as in claim 8, wherein the slot consists of 7
`
`symbols, the at least one reference signal is mapped to a 4th
`
`symbol among the 7 symbols, and the acknowledgement
`
`information is mapped only to 3rd and 5th symbols among the
`
`7 symbols.
`
`10. The method as in claim 8, wherein said some ofthe data
`
`information and the acknowledgement information is respec
`
`tively transmitted over different subcarriers for transmission
`
`of the ?rst symbols.
`
`1 1. The method as in claim 8, wherein both said some ofthe
`
`data information and the acknowledgement information is
`
`20 mapped to the ?rst symbols.
`
`12. A method for receiving a signal in a slot of a subframe
`
`in a wireless communication system, the signal including data
`
`information, and acknowledgement information, the method
`
`comprising:
`
`receiving the signal including the data information, the
`
`acknowledgement information, and a reference signal,
`
`the reference signal being mapped to a middle symbol in
`
`the slot;
`
`de-mapping the acknowledgement information that is
`
`mapped only in ?rst symbols among remaining symbols
`
`in the slot, the reference signal being not mapped to the
`
`?rst symbols; and
`
`de-mapping the data information mapped to the remaining
`
`symbols,
`
`wherein some of the data information is mapped to the ?rst
`
`symbols that are directly adjacent to the middle symbol.
`
`13. The method as in claim 12, wherein said some of the
`
`data information and the acknowledgement information is
`
`respectively received over different subcarriers for transmis
`
`40 sion of the ?rst symbols.
`
`14. The method as in claim 12, wherein both said some of
`
`the data information and the acknowledgement informat