(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2008/0304467 A1
`Papasakellariou et al.
`(43) Pub. Date:
`Dec. 11, 2008
`
`US 20080304467A1
`
`(54)
`
`(75)
`
`(73)
`
`(21)
`(22)
`
`(60)
`
`CONTROLAND DATA SIGNALING IN
`SC-FDMA COMMUNICATION SYSTEMS
`
`Inventors:
`
`Aris Papasakellariou, Dallas, TX
`(US); Joon-Young Cho, Suwon-si
`(KR)
`Correspondence Address:
`THE FARRELL LAW FIRM, P.C.
`333 EARLE OVINGTON BOULEVARD, SUITE
`TO1
`UNIONDALE, NY 11553 (US)
`Assignee:
`SAMSUNGELECTRONICS
`CO.,LTD., Suwon-si (KR)
`12/133,120
`
`Appl. No.:
`
`Filed:
`
`Jun. 4, 2008
`Related U.S. Application Data
`Provisional application No. 60/942,843, filed on Jun.
`8, 2007.
`
`Nx12 SUB-CARRIERS (150)
`a- - - - - - - - ->
`
`2222 % %.
`
`a
`
`Publication Classification
`
`(51) Int. Cl.
`H04B 7/28
`
`(2006.01)
`
`(52) U.S. Cl. ........................................................ 370/344
`
`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/NAKbits 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.
`
`RS
`DATA
`
`SYMBOL
`(130)
`
`---4RS4-H-4RS4--
`ONE SLOT (i2O)
`
`ONE SUB-FRAME (110)
`
`

`

`Patent Application Publication
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`US 2008/0304467 A1
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`Patent Application Publication
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`Dec. 11, 2008 Sheet 3 of 10
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`US 2008/0304467 A1
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`Patent Application Publication
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`Dec. 11, 2008 Sheet 4 of 10
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`Patent Application Publication
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`Dec. 11, 2008 Sheet 5 of 10
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`US 2008/0304467 A1
`
`RAW BER FOR SLOT DATA SYMBOLS
`I.
`- - - - - - -
`-- - - - - - - - - - - - - - - - - - - - - - - - - - - - -.
`- - - - - - - - - - - - - - - - - - - -
`- - - - - - - - - -
`- - - - - - - - - - - - - - - - - - - - - - - - -
`-
`T - - - - - - - - - - - --
`- - - - - - - - -
`as - - - - - - - - - - - - - - - -
`- a
`1 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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`0.
`-- - - - - - -
`- - - - - - - - - -
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`- - - - - - - - - - - - - - - - - - - - - - - - - -
`is - - - - - R.
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`- - - - - - - - an
`-- - - - - -
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`I
`l.
`-- - - - -Ya.
`- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
`
`ESSESS
`
`-e-3 Kmph, 117 Symbol
`-- 3 Kmph
`16 Symbol
`2
`-- 3 Kmph,3
`15 Symbol
`- - - - - - - - - - - - - - - - - - - - - - - - - - - - -
`- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -N.
`-E-350 Kmph, 17 Symbol - - - -
`-e- 350 Kmph,216 Symbol
`1-------------l- - - - - - - - - - - - - - - - - -
`-- 350 Kmph,
`315 Symbol
`RB
`TU6,
`QPSK
`
`- - - - - - - - - - - - - - - - - -k- - - - - - - - - - - - - - - - - - - -
`
`
`
`
`
`SNR (dB)
`RAW BER FOR SLOT DATA SYMBOLS
`
`- - - - - - - - - - - - - - - - - - - - - - - - - - -
`- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
`- - - - - -- a- - - - - - - - - - - - - - - r n is
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`rs
`V- a - - - - - - - - - - - as a r
`s m = -
`- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
`
`---------------------------------
`--------------------------------
`
`w
`
`- - - - - - - -
`- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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`--------------
`-------------
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`- - - - - - - - - - - - - - - - - - - - - - - - - -
`- - - - - - - - - - - - -
`-
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`- - - - - - - - - - - - - -
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`r
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`EEEEEEE
`CCC
`i
`-e- 30 Kmph, 117 Symbol
`- - - - - - - - - -
`- - - - - - - - - - - - - - - - - - - -
`--------------------
`-K-30 Kmph
`ymbol
`26S
`-
`-H 30 Kmph,315 Symbol
`- - - - - - - - - - - - - - - -
`-- 120 Kmph, 117 Symbol - - - -
`-e- 20 Kmp
`h.2/6 Symbol
`Symbol
`E.
`-- 120K
`3
`1 RB
`Q
`-4
`-2
`O
`
`- - - - - - - - - - - - - - - - - - - - - - - - - - - -
`
`- - - - - - - - - - - - - - - - - - is - - - - - - - - - - - - - - - - - - -
`
`-6
`
`SNR (dB)
`FIG.5
`
`

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`Patent Application Publication
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`Dec. 11, 2008 Sheet 6 of 10
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`US 2008/0304467 A1
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`Patent Application Publication
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`Dec. 11, 2008
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`Sheet 7 of 10
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`US 2008/0304467 A1
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`Patent Application Publication
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`Dec. 11, 2008
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`Sheet 8 of 10
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`US 2008/0304467 A1
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`Patent Application Publication
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`Dec. 11, 2008
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`Sheet 9 of 10
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`US 2008/0304467 A1
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`Patent Application Publication
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`Dec. 11, 2008
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`Sheet 10 of 10
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`US 2008/0304467 A1
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`US 2008/0304467 A1
`
`Dec. 11, 2008
`
`CONTROLAND DATA SIGNALING IN
`SC-FDMA COMMUNICATION SYSTEMS
`
`PRIORITY
`
`0001. The present Application for Patent claims priority to
`U.S. Provisional Application No. 60/942,843 entitled “Con
`trol and Data Signaling in SC-FDMA Communication Sys
`tems' filed Jun. 8, 2007, the contents of which is incorporated
`by reference herein.
`
`BACKGROUND OF THE INVENTION
`
`0002 1. Field of the Invention
`0003. The present invention is directed, in general, to
`wireless communication systems and, more specifically, to
`multiplexing control and data information in single-carrier
`frequency division multiple access (SC-FDMA) communica
`tion systems.
`0004 2. Description of the Related Art
`0005. In particular, the present invention considers the
`transmission 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 communications system and is further considered in
`the development of the 3' Generation Partnership Project
`(3GPP) Evolved Universal Terrestrial Radio Access
`(E-UTRA) longterm evolution (LTE). The invention assumes
`the uplink (UL) communication corresponding to the signal
`transmission from mobile user equipments (UES) to a serving
`base station (Node B). A UE, also commonly referred to as a
`terminal or a mobile station, may be fixed 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
`fixed station and may also be called a base transceiver system
`(BTS), an access point, or some other terminology. The ACK/
`NAK bits and CQI bits may also be referred to simply as
`control information bits.
`0006. The ACK or NAK bits are in response to the correct
`or incorrect, respectively, data packet reception in the down
`link (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 of the channel conditions the UE experiences
`for signal reception, enabling the Node B to perform channel
`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
`transmission of the ACK/NAK and/or CQI.
`0007. The UEs are assumed to transmit control and data
`bits over a TTI corresponding to a sub-frame. FIG. 1 illus
`trates a block diagram of the sub-frame structure 110
`assumed in the exemplary embodiment of the disclosed
`invention. The sub-frame includes two slots. Each slot 120
`further includes seven symbols and each symbol 130 further
`includes of a cyclic prefix (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 parts of the operating band
`width. 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 estimation for coherent demodulation
`of the received signal.
`0008. The transmission bandwidth (BW) is assumed to
`include frequency resource units, which will be referred to
`herein as 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.
`0009. 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. IfACK/NAK bits also need to be multiplexed, the exem
`plary embodiment assumes that data bits are punctured to
`accommodate ACK/NAKbits 230. Alternatively, COI 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 trans
`form (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
`finally the cyclic prefix (CP) 270 and filtering 280 are applied
`to the transmitted signal 290.
`0010 Alternatively, as illustrated in FIG. 3, in order to
`transmit the control (ACK/NAK and/or CQI) bits 310, punc
`turing 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 finally the
`cyclic prefix (CP) 370 and filtering 380 are applied to the
`transmitted signal 390.
`0011. 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 of the 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, addi
`tional transmitter circuitry such as digital-to-analog con
`Verter, analog filters, amplifiers, and transmitterantennas 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.
`0012. At the receiver, the inverse (complementary) trans
`mitter operations are performed. This is conceptually illus
`trated in FIG. 4 where the reverse operations of those illus
`trated 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
`filters, amplifiers, 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. Subsequently, 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
`
`

`

`US 2008/0304467 A1
`
`Dec. 11, 2008
`
`de-multiplexes 480 the data bits 490 and CQIbits 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.
`0013 The control bits typically require better reception
`reliability than the data bits. This is primarily because hybrid
`automatic-repeat-request (HARO) usually applies to data
`transmission 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 detrimental consequences to the overall quality and
`efficiency of communication than does erroneous reception
`for the CQI bits.
`0014. 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 trans
`mission 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.
`0015 There is a need to determine the placement of con
`trol 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.
`0016. 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.
`0017. 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 chan
`nel conditions experienced by the signal transmission from a
`UE.
`
`SUMMARY OF THE INVENTION
`0018. Accordingly, the present invention has been
`designed to 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.
`0019. In accordance with an embodiment of the present
`invention, provided are an apparatus and method for the
`placement of signals carrying the control bits and data bits in
`transmission symbols relative to the symbols used for trans
`mission of reference signals in order to enable better recep
`tion reliability of the control bits.
`0020. Another embodiment of the present invention pro
`vides an apparatus and method for the placement of acknowl
`edgement bits with higher priority than channel quality indi
`cation bits to enable better reception reliability of the
`acknowledgement bits.
`0021. Another embodiment of the present invention pro
`vides 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.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`0022. The above and other aspects, features, and advan
`tages of the present invention will be more apparent from the
`following detailed description taken in conjunction with the
`accompanying drawings, in which:
`
`0023 FIG. 1 is a block diagram illustrating an exemplary
`sub-frame structure for the SC-FDMA communication sys
`tem;
`0024 FIG. 2 is a block diagram illustrative of a first exem
`plary SC-FDMA transmitter for multiplexing data bits, COI
`bits, and ACK/NAK bits in a transmission sub-frame;
`0025 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;
`0026 FIG. 4 is a block diagram illustrative of an exem
`plary SC-FDMA receiver, corresponding to the first exem
`plary SC-FDMA transmitter, for de-multiplexing data bits,
`CQI bits, and ACK/NAK bits in a reception sub-frame;
`(0027 FIG.5 presents un-coded biterror rate (BER) results
`as a function of the symbol number (symbol position) in the
`sub-frame slot and the UE velocity;
`0028 FIG. 6 is a block diagram illustrating a first method
`for the selection of the sub-frame symbols carrying the trans
`mission of CQI bits and ACK/NAK bits:
`0029 FIG. 7 is a block diagram illustrating a first method
`for the selection of the sub-frame symbols carrying the trans
`mission of ACK/NAK bits:
`0030 FIG. 8 is a block diagram illustrating a first method
`for the selection of the sub-frame symbols carrying the trans
`mission of CQI bits:
`0031
`FIG. 9 is a block diagram illustrating a second
`method for the selection of the sub-frame symbols carrying
`the transmission of ACK/NAK bits with reduced overhead;
`and
`0032 FIG. 10 is a block diagram illustrating a second
`method for the selection of the sub-frame symbols carrying
`the transmission CQI bits and ACK/NAK bits.
`
`DETAILED DESCRIPTION OF THE
`EXEMPLARY EMBODIMENTS
`0033. The present invention now will be described more
`fully hereinafter with reference to the accompanying draw
`ings. This invention may, however, be embodied in many
`different forms and should not be construed as limited to the
`embodiments set forth herein. Rather, these embodiments are
`provided so that this disclosure will be thorough and com
`plete, and willfully convey the scope of the invention to those
`skilled in the art.
`0034 Additionally, although the invention assumes a
`single-carrier frequency division multiple access (SC
`FDMA) communication system, it also applies to all FDM
`systems in general and to OFDMA, OFDM, FDMA, DFT
`spread OFDM, DFT-spread OFDMA, single-carrier
`OFDMA (SC-OFDMA), and single-carrier OFDM in par
`ticular.
`0035 Basically, the system and methods of the embodi
`ments 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.
`0036. A first observation for the sub-frame structure illus
`trated 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 Substan
`tially degraded channel estimation for symbols located fur
`ther away from the RS (that is, for symbols near the beginning
`
`

`

`US 2008/0304467 A1
`
`Dec. 11, 2008
`
`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 blockerror rate (BLER), such as 10% or
`above, and can benefit from retransmissions though a con
`ventional HARQ process. Conversely, the CQI and particu
`larly the ACK/NAK have much stricter performance require
`ments, HARO typically does not apply to the corresponding
`transmissions, and providing an accurate channel estimate is
`essential in achieving the desired reception reliability.
`0037. A brief set of simulation results for the un-coded
`(raw) bit error rate (BER) is provided to illustrate the impact
`of inaccurate channel estimation on the reception quality as a
`function of the symbol position in the slot and the UE speed.
`Table I provides the simulation setup under optimistic condi
`tions for the performance loss due to imperfect channel esti
`mation at symbols further away from the RS for the following
`CaSOS
`0038 Transmission bandwidthis 1 RB. This maximizes
`power per Sub-carrier.
`0039 Channel frequency selectivity is large and there
`are 2 uncorrelated Node B receiver antennas. This maxi
`mizes the slope of the un-coded (raw) BER curve and
`minimizes the relative performance loss due to imper
`fect channel estimation for a target BER value.
`0040. 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 (a)
`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 (a) 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 loca
`0041
`tions symmetric to the RS, the BER is typically the same. At
`120 Kmph and 350 Kmph, the transmission in the first slot is
`assumed to occurata 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.
`0042 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 177" and 2"/6" symbols. However,
`the impact on the BER of the 3"/5' 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 1/7'
`symbols and by about 1.5 dB for the 2"/6" symbols relative
`to the one of the 3/5' symbols at about the 1% point.
`Obviously, due to the flattening of the BER curves for the
`1/7' and 2"/6' symbols, the degradation will be much
`larger for BER operating points below 1% as it is typically
`needed for the NAK reception.
`0043 Based on the results in FIG. 5 it becomes apparent
`that the control transmission should be placed with priority
`immediately next to the RS.
`0044 FIG. 6 illustrates such a placement when a UE trans
`mits both ACK/NAK bits 610 and CQI 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
`transmitted 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 CQI bits.
`004.5
`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/NAKbits are placed at the two symbols
`next to the RS730 in each of the two sub-frameslots while the
`data bits are included in symbols transmitted over the entire
`sub-frame.
`0046 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.
`0047. To minimize channel estimation losses, the ACK/
`NAK bits should be placed with priority in the symbol after
`the first symbol carrying the RS. This does not impact
`demodulation latency as a channel estimate is available only
`after this first 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/NAKbits benefits from improved channel
`estimation and time diversity while for high UE speeds, it
`benefits from frequency and time diversity. This is illustrated
`in FIG.9 where the ACK/NAKbits 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 are transmitted throughout the sub-frame (with
`the obvious exception of the symbols carrying the RS).
`0048 Provisioning for the transmission of ACK/NAKbits
`in the Sub-carriers over 2 symbols is typically adequate to
`achieve the desired BER for the ACK reception. Neverthe
`less, 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 slots may also be used as illustrated in FIG. 6 and FIG.
`7
`0049. Depending on the number of information bits car
`ried in the COI reporting, which are typically several times
`more than the ACK/NAK information bits, the symbols
`
`

`

`US 2008/0304467 A1
`
`Dec. 11, 2008
`
`immediately adjacent to the RS may not suffice for the CQI
`transmission, especially for coverage or SINR limited UEs
`that are also typically assigned Small bandwidth allocations (a
`small number of RBs). In such cases, the CQI transmission
`may also extend to one or more symbols that are adjacent to
`the symbols also carrying CQI information that are adjacent
`to the symbols carrying the RS. An exemplary embodiment of
`this principle is illustrated in FIG. 10. As previously dis
`cussed, the location of the ACK/NAK bits 1010 remains in
`symbols next to the RS 1030 but the CQIbits 1020 are located
`in symbols throughout the transmission Sub-frame, similarly
`to the data symbols 1040.
`0050. 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 departing from the spirit and scope of the invention as
`defined by the appended claims.
`What is claimed is:
`1. An apparatus for forming a signal in a communication
`system, the signal being transmitted over a time period
`including a plurality of symbols with at least one symbol of
`the plurality of symbols carrying a reference signal and
`remaining symbols of the plurality of symbols carrying an
`information signal, the information signal including at least
`control information bits and data information bits, said appa
`ratus comprising:
`a mapping unit for placing at least one of the control bits in
`at least one of the remaining symbols located only next
`to the at least one symbol carrying the reference signal,
`for placing at least one of the data information bits in at
`least one of the remaining symbols not located next to
`the at least one symbol of the symbols carrying the
`reference signal; and
`a transmitter unit for transmitting during the at least one of
`the plurality of symbols carrying the reference signal
`and transmitting during the remaining symbols of said
`the plurality of symbols carrying the information signal.
`2. The apparatus as in claim 1, wherein the control infor
`mation bits comprise acknowledgement bits.
`3. The apparatus as in claim 1, wherein the control infor
`mation bits comprise channel quality indication bits.
`4. The apparatus as in claim 1, wherein the communication
`system comprises a single-carrier frequency division mul
`tiple access (SC-FDMA) communication system and the
`transmitter uses the SC-FDMA transmission method.
`5. An apparatus for forming a signal in a communication
`system, the signal being transmitted over a time period
`including a plurality of symbols with at least one symbol of
`the plurality of symbols carrying a reference signal and
`remaining symbols of the plurality of symbols carrying an
`information signal, the information signal including
`acknowledgement bits, channel quality indication bits, and
`data information bits, the apparatus comprising:
`a mapping unit for placing at least one of the acknowledge
`ment bits in at least one of the remaining symbols
`located only next to the at least one symbol carrying the
`reference signal, for placing at least one of the channel
`quality indication bits in at least one of the remaining
`symbols not located next to the at least one symbol of the
`symbols carrying the reference signal, and for placing at
`least one of the data information bits in at least one of the
`remaining symbols not located next to the at least one
`symbol of the symbols carrying the reference signal; and
`
`a transmitter unit for transmitting during the at least one of
`the plurality of symbols carrying the reference signal
`and transmitting during the remaining symbols of the
`plurality of symbols carrying the information signal.
`6. The apparatus as in claim 5, wherein the communication
`system comprises a single-carrier frequency division mul
`tiple access (SC-FDMA) communication system and the
`transmitter uses the SC-FDMA transmission method.
`7. An apparatus for forming a signal in a communication
`system, the signal being transmitted over a time period
`including a plurality of symbols with at least two symbols of
`the plurality of symbols carrying a reference signal and
`remaining symbols of the plurality of symbols carrying an
`information signal, the information signal including
`acknowledgement bits and data bits, the apparatus compris
`1ng:
`a mapping unit for placing the acknowledgement bits only
`at a symbol after a first of the at least two symbols
`carrying the reference signal and only at a symbol before
`a last of the at least two symbols carrying the reference
`signal, and for placing the data bits in at least one of the
`remaining symbols not located next to the at least two
`symbols carrying the reference signal; and
`a transmitter unit for transmitting during the at least two
`symbols carrying the reference signal and transmitting
`during the remaining symbols carrying the information
`signal.
`8. The apparatus as in claim 7, wherein the communication
`System comprises a single-carrier frequency division mul
`tiple access (SC-FDMA) communication system and the
`transmitter uses the SC-FDMA transmission method.
`9. An apparatus for forming a signal in a user equipment,
`the signal being transmitted over a time period in a channel
`medium, the time period including a plurality of symbols with
`at least one symbol of the plurality of symbols carrying an
`information signal, the information signal including
`acknowledgement bits and data bits, the apparatus compris
`ing:
`a mapping unit for placing the acknowledgement bits in a
`first set of resources when the user equipment operates
`in first channel medium conditions, and for placing the
`acknowledgement bits in a second set of resources when
`the user equipment operates in second channel medium
`conditions; and
`a transmitter unit for transmitting during the at least one
`symbol carrying the information signal.
`10. The apparatus as in claim 9, wherein the channel
`medium conditions correspond to a signal-to-interference
`and noise ratio (SINR).
`11. The apparatus as in claim 9, wherein the communica
`tion system comprises a single-carrier frequency division
`multiple access (SC-FDMA) communication system and the
`transmitter uses the SC-FDMA transmission method.
`12. An apparatus for forming a signal in a communication
`system, the apparatus comprising:
`a tran