Title of Invention

ENCODING UPLINK ACKNOWLEDGMENTS TO DOWNLINK TRANSMISSIONS

Abstract A portable device, such as a mobile terminal or user equipment fur encoding uplink acknowledgments to downlink transmissions. The portable device includes a receiver configured to received a plurality of data blocks, such that each of the data blocks include an associated cyclic redundancy cheek (CRC), and a processor configured to determine received status for each of the data blocks by checking the CRC of each of the data blocks. The portable device further includes a transmitter for transmitting a response sequence which indicates the received status of all of the data blocks.
Full Text ENCODING UPLINK ACKNOWLEDGMENTS
TO DOWNLINK TRANSMISSIONS
Field of the Invention
The present invention relates to wireless communications, and in particular, to
encoding uplink acknowledgments to downlink transmissions.
Discussion of the Related Art
One multiple carrier communication scheme transmits data through a number
of orthogonal subcarriers. Examples of such systems, which typically require a high data rate,
include wireless location area networks (LANs) and mobile Internet technologies. Typical
multiple carrier communication schemes include orthogonal frequency division multiplexing
(OFDM), discrete Fourier transform-spreading-orthogonal frequency division multiplexing
(DFT-S-OFDM or DFT-Spreading-OFDM) (also referred to as SC-FDMA), and orthogonal
frequency division multiplexing access (OFDMA). Although OFDM and OFDMA can
achieve a high transfer rate by keeping subcarriers orthogonal, such techniques often have a
high peak-to-average power ratio (PAPR). DFT-S-OFDMA is a technique which may be
implemented to overcome the PAPR problem, for example. DFT-S-OFDMA functions by
first spreading signals with a DFT matrix in the frequency domain before generating OFDM
signals. The signals which were spread may then be modulated and transmitting in known
fashion using conventional OFDM techniques. This technique will now be described.
Fig. 1 is a flowchart depicting the generation of a transmission signal _
according to a conventional DFT-S-OFDMA system. According to blocks 110 and 120, a
typical DFT-S-OFDM wireless communication system spreads signals using a DFT matrix
before generating the OFDM signals. Consider an equation in which "s" is an input data -
symbol, "x" is data spread in the frequency domain, and "Nb" is the number of subcarriers for
a particular user. In such a scenario, the spread data "x" may be obtained using the
following:

According to blocks 130, 140, and 150, the spread vector "x" is shown
mapped to a subcarrier according to a subcarrier mapping technique, and is then transformed
into the time domain through an inverse discrete Fourier transform (IDFT) module to obtain a
signal for transmission to a receiving entity. The transmission signal "y" may be obtained
using the following:

p
where NxN is an NxN DFT matrix used to transform a frequency domain
signal into a time domain signal. The signal "y" generated in this manner is transmitted with
an inserted cyclic prefix (block 160).
Data, pilots, and control information are then transmitted in the uplink of
multiple carrier systems, including, for example, the DFT-S-OFDM system. Control
information can be divided into data-associated control information, which is associated with
data demodulation, and non-data-associated control information, which is not associated with
data demodulation.
Data-associated control information includes control information required to
reconstruct data transmitted by user equipment (UE). For example, data-associated control
information may include information associated with the transmit format or information
associated with hybrid automatic repeat-request (HARQ). The amount of the data-associated
control information can be adjusted according to an uplink data scheduling scheme.
On the other hand, non-data-associated control information is control
information required for downlink transmission. For example, the non-data-associated
control information may include acknowledgment (ACK) or negative acknowledgment
(NACK) information for HARQ operation, and a channel quality indicator (CQI) for link
adaptation of the downlink.
In an uplink multi-carrier or single-carrier FDMA system, control information
is divided into a data-associated control information for demodulating user data and non-data-
associated control information for downlink transmission. A basic principle of OFDM
includes dividing a data stream having a high data rate into a plurality of data streams, each
of which has a slow data rate, and then transmitting the data streams simultaneously using a
plurality of camera. Each the carriers is referred to as a subcarrier. Since orthogonality
exists between the carriers of OFDM, if frequency components of the carriers are overlapped
with each other, a transmitting terminal can still detect the frequency components.
The data stream having the high data rate is converted to a plurality of data
streams having slow data rates via a serial to parallel converter. Each of the parallel-
converted data streams is multiplied by a corresponding subcarrier, added together, and then
transmitted to the receiving terminal.
The parallel data streams generated, by the serial to parallel converter can be
transmitted as a plurality of subcarriers by IDFT. IDFT can be efficiently implemented using
an inverse fast Fourier transform (IFFT).
As symbol duration of the subcarrier having the slow data rate increases,
relative signal dispersion, which occurs by multi-path delay spreading, decreases on the time
domain. Inter-symbol interference may be reduced by inserting a guard interval longer than
the channel delay spreading between OFDM symbols. If a portion of an OFDM signal is
copied to the guard interval and arranged at a start portion of the symbol, the OFDM symbol
is cyclically extended to be protected.
The amount of frequency resources used for data transmission may be reduced
if the UE allocates a sufficient number of subcarriers to non-data-associated-control
information when transmitting the control information in the uplink. This technique
consequently results in a large number of subcarriers which are unable to be allocated, thus
affecting the ability to achieve diversity gain in the frequency domain.
A typical UE separately transmits ACK/NACK and CQI signals among non-
data-associated control information in the uplink. For example, the UE transmits the
ACK/NACK signal, the CQI signal, or both of these signals at a particular time period.
However, conventional multiple carrier systems do not typically distinguish between such
signals when processing the non-data-associated control information. This prevents efficient
utilization of frequency resources.
If ACK/NACK and CQI signals are transmitted using a single discrete Fourier
transform (DFT) in the uplink of the DFT-S-OFDM communication system, a number of
users will typically share the same resource unit. For instance, if one user transmits an
ACK/NACK signal and another user transmits a CQI signal with the same resource unit, it
may not be possible for a base station to demodulate the ACK/NACK and CQI signals of the
two users.
SUMMARY OF THE INVENTION
Features and advantages of the invention will be set forth in the description
which follows, and in pail will be apparent from the description, or may be learned by
practice of the invention. The objectives and other advantages of the invention will be
realized and attained by the structure particularly pointed out in the written description and
claims hereof as well as the appended drawings.
hi accordance with an embodiment, a method for encoding uplink
acknowledgments to downlink transmissions includes receiving a plurality of data blocks,
such that each of the data blocks include an associated cyclic redundancy check (CRC). The
method further includes determining received status for each of the data blocks by checking
the CRC of each of the data blocks, and generating a response sequence which indicates the
received status of all of the data blocks.
According to one feature, the data blocks include a primary transport block
and a secondary transport block.
According to another feature, the response sequence is a discrete response
sequence.
According to yet another feature, the method further includes generating the
response sequence as a single response sequence which indicates the received status of all of
the data blocks.
According to still yet another feature, the receiving of the data blocks is from a
Node B.
According to one aspect, the status is either an acknowledgment (ACK) which
identifies a data block which has been received without error, or a negative acknowledgment
(NACK) which identifies a data block which has been received with an error.
According to another aspect, the method further includes modulating the
response sequence using QPSK modulation.
According to yet another aspect, the method further includes transmitting the
response sequence to a Node B.
According to still yet another aspect, the downlink transmissions include
multiple input multiple output (MIMO) transmissions.
According to one feature, the method further includes receiving the data
blocks in parallel.
According to another feature, the downlink transmissions comprise time
division duplex (TDD) transmissions.
According to yet another feature, the method further includes either
sequentially receiving the data blocks or receiving the data blocks in parallel.
In accordance with an alternative embodiment, a method for receiving
encoded uplink acknowledgments to downlink transmissions includes transmitting in parallel
a plurality of data blocks, such that each of the data blocks include an associated cyclic
redundancy check (CRC). The method further includes receiving a single response sequence
which indicates received status of all of the data blocks.
In accordance with another alternative embodiment, a portable device for
encoding uplink acknowledgments to downlink transmissions includes a receiver configured
to receive a plurality of data blocks, such that each of the data blocks include an associated
cyclic redundancy check (CRC), and a processor configured to determine received status for
each of the data blocks by checking the CRC of each of the data blocks. The portable device
further includes a transmitter for transmitting a response sequence which indicates the
received status of all of the data blocks.
In accordance with yet another embodiment, a transmitting entity operable in a
wireless communication system and configured to receive encoded uplink acknowledgments
to downlink transmissions includes a transmitter for transmitting in parallel a plurality of data
blocks, such that each of the data blocks include an associated cyclic redundancy check
(CRC), and a receiver for receiving a single response sequence which indicates received
status of all of the data blocks.
In accordance with still yet another embodiment, a method for encoding
uplink acknowledgments to downlink transmissions includes receiving a plurality of data
blocks, such that each of the data blocks include an associated cyclic redundancy check
(CRC), determining received status for each of the data blocks by checking the CRC of each
of the data blocks, and generating a response bit according to the status. The method further
includes mapping the response bit to a fixed length sequence to generate a mapped sequence,
transmitting the mapped sequence in an uplink transmission, and repeating the mapping and
transmitting for a predetermined time period.
These and other embodiments will also become readily apparent to those
skilled in the art from the following detailed description of the embodiments having reference
to the attached figures, the invention not being limited to any particular embodiment
disclosed.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other aspects, features, and advantages of the present invention
will become more apparent upon consideration of the following description of preferred
embodiments, taken in conjunction with the accompanying drawing figures, wherein:
Fig. 1 is a flowchart depicting the generation of a transmission signal
according to a conventional DFT-S-OFDMA system;
Fig. 2A shows a UE transmitting in the uplink to collectively spread the
control information vectors to obtain a spread vector;
Fig. 2B shows another arrangement for uplink transmissions in a DFT-S-
OFDM wireless communication system according to an alternative embodiment of the
present invention;
Fig. 2C shows yet another arrangement for uplink transmissions in a DFT-S-
OFDM wireless communication system according to an alternative embodiment of the
present invention;
Fig. 3 A depicts an uplink subframe format using time division multiplexing
(TDM) in a DFT-S-OFDM wireless communication system;
Fig. 3B depicts an uplink subframe format using frequency division
multiplexing (FDM) in a DFT-S-OFDM wireless communication system;
Figs. 4A and 4B are block diagrams depicting techniques for reducing the
BER in a transmitting UE operating within a DFT-S-OFDM wireless communication system
according to an embodiment of the present invention;
Fig. 5 is a block diagram depicting a method for selecting a subcarrier to be
allocated according to an embodiment of the present invention;
Fig. 6 shows an uplink subframe format;
Figs. 7 and 8 depict uplink multiplexing schemes;
Figs. 9A-9C depict embodiments which relates to allocating a frequency
resource for ACK/NACK signal transmission in the uplink of a SC-FDMA/OFDMA system;
Figs. 10A and 10B are block diagrams depicting SCW and MCW transmitting
terminals configured for use in a MIMO wireless mobile communication system;
Fig. 11 is a block diagram of an ACK/NACK transmitting apparatus according
to an embodiment of the present invention;
Fig. 12 is a block diagram of an ACK/NACK transmitting apparatus according
to another embodiment of the present invention;
Fig. 13A depicts localized allocation of a number of subcarriers;
Fig. 13B depicts distributed allocation of a number of subcarriers;
Fig. 14 is a block diagram depicting a method for uplink transmission using
OFDM;
Fig. 15 is a flowchart depicting the generation of a transmission signal
according to DFT-S-OFDMA;
Fig. 16 provides an example of closely arranged subcarriers;
Fig. 17 provides an example of a subcarrier arrangement using enhanced
localized allocation;
Fig. 18 shows a distribution of subcarriers used for ACK/NACK signal
transmission;
Figs. 19 A and 19B depict a subcarrier arrangement using enhanced distributed
allocation, in which a pair of subcarriers is configured as a group; and
Figs. 20A and 20B depict further subcarrier arrangements.
IWTAfT.F.n INSCRIPTION OF THE PREFERRED EMBODIMENTS
In the following detailed description, reference is made to the accompanying
drawing figures which form a part hereof, and which show by way of illustration specific -
embodiments of the invention. It is to be understood by those of ordinary skill in this
technological field that other embodiments may be utilized, and structural, electrical, as well
as procedural changes may be made without departing from the scope of the present
invention. Wherever possible, the same reference numbers will be used throughout the
drawings to refer to the same or similar parts.
Various embodiments will be described in conjunction with a UE. However,
such teachings apply also to other types of wireless terminals such as mobile terminals,
mobile stations, and the like.
Spreading of Control Information Vectors in Uplink
Figs. 2A-2C are block diagrams which illustrate various elements of an uplink
transmitting entity operable within a DFT-S-OFDM wireless communication system in
accordance with an embodiment of the present invention. Consider first a UE configured as
the transmitting entity in such a communication system. The UE may receive and distinguish
control information such as ACK/NACK, a channel quality indicator (CQI), and other types
of non-data-associated control information. Such control information is not associated with
data demodulation. Generally, an ACK/NACK is a vector that includes one or more bits
which are based upon the number of cyclic redundancy codes (CRCs) inserted into the
downlink signal. The CQI is a vector that generally includes a plurality of bits to report a
channel quality state to an associated base station or Node B, for example. The CQI
facilitates downlink scheduling at the base station. By way of non-limiting example,
embodiments will be described in which the size of the ACK/NACK vector is "1" and the
size of the CQI vector is "m."
Fig. 2A shows a UE transmitting in the uplink to collectively spread the
control information vectors (sized 1+m through DFT) to obtain a spread vector (X'ack+cqi)
with a size of n bits (n=l+m), without distinguishing between the ACK/NACK vector of size
1 and the CQI vector of size m. Another operation performs an inverse fast Fourier transform
(IFFT) on vector (X"ack+cqi) obtained through subcarrier mapping to acquire and transmit
time information (Yack+cql)-
In this scenario, if one UE transmits an ACK/NACK and another UE transmits
CQI using the same resource block, it is difficult for a receiving base station to select an
IDFT for despreading a vector X'ack+cqi that is obtained by removing each subcarrier from a
vector X"ack+cql- The vector X"ack+cqi. may be obtained by the base station through a fast
Fourier transform (FFT) which corresponds to the IFFT performed at the transmitting end.
Signals transmitted by the UEs are typically indistinguishably spread in the vector X"ack+cqi
and the vector X'ack+cqi- This is because it may be necessary to distinguish between IDFTs
used to analyze received signals from two or more UEs, if the UEs use the same resource
block.
Fig. 2B shows another arrangement for uplink transmissions in a DFT-S-
OFDM wireless communication system according to an alternative embodiment of the
present invention. A UE configured to transmit according to this figure distinguishes and
receives various types of control information (described above). In this example, the UE
spreads the ACK/NACK and CQI control information using different DFTs before mapping
these parameters to corresponding subcarriers. Since the ACK/NACK vector (Xack) of size
1 and the CQI vector (Xcqi) of size m are spread using different DFTs, their spread vectors
(Xjack) and (X'cqi) of size 1 and m, respectively, also include ACK/NACK information and
CQI information.
The spread vectors (X'ack) and (X'cqi) are shown mapped to corresponding
subcarriers, which are subjected to the IFFT and subsequently transmitted to the base station.
According to this embodiment, if one UE transmits an ACK/NACK and another UE transmits
CQI using the same resource block, the base station can easily select IDFTs for despreading
vectors X'ack. and X'cqi that are each obtained by respectively removing subcarriers from
vectors X"ack and X"cqi. The vectors X"ACk and X"cqi may be obtained by the base station
through a FFT coiTesponding to the 1FFT that was performed at the transmitting end, which
in the illustrated case is the UE.
Fig. 2B is an example which distinguishes between control information such
as ACK/NACK and CQI. However other types of information may be similarly
distinguished using the illustrated techniques. For example, the techniques of this figure may
also be applied to situations in which two or more control signals (or information) are
received and spread using different DFTs before being mapped to a frequency resource for
transmission through the uplink. This allows a receiving entity, which receives the uplink
signal, to distinguish between the transmitted two or more types of control information
through control information that is demapped from the frequency resource.
The embodiment of Fig. 2B separately spreads control information using
separate DFTs, but alternatives are possible and envisioned by the present disclosure. For
example, the separate DFT processes may alternatively include any process, provided that
such processes allow the entity receiving the uplink signal to distinguish between the
different types of control information.
Fig. 2C shows another arrangement for uplink transmissions in a DFT-S-
OFDM wireless communication system according to an alternative embodiment of the
present invention. In this embodiment, the transmitting UE, for example, directly maps
ACK/NACK control information to a subcarrier. This is accomplished without performing
DFT, and results in obtaining the vector X"ack.- Fig. 2C further shows transforming CQI
control information using a DFT, and then mapping the resulting spread vector X'cqi to a
subcarrier to obtain a vector X"co>
Generally, the size of the vector corresponding to the ACK/NACK
information is smaller than the size of the vector corresponding to the CQI information. Thus
the effects achieved by spreading the vector corresponding to the ACK/NACK information
are relatively small. This embodiment is simplified to the extent that the DFT processing of
the ACK/NACK signal is omitted. However, this embodiment achieves effects similar to
those of the case of Fig. 2B since the base station can correctly distinguish between
information items that have been subjected to a FFT. If desired, the embodiment of Fig. 2C
may alternatively include any separate process, other than the separate DFT spreading,
provided that such a process allows the receiving entity to distinguish between the different
types of control information.
The embodiment of Fig. 2C may farther include a structure for improving
peak-to-average power ratio (PAPR) performance. For example, if the ACK/NACK signal is
directly mapped to a subcarrier without DFT, and it is then subjected to IFFT for transmission,
the compensation effects between DFT and IFFT may degrade the PAPR performance
(relative to performance which may be achieved by the configuration of Fig. 2B). As such, a
UE configured in accordance with Fig. 2C may select a specific subcarrier for improving the
PAPR performance, and then map the ACK/NACK signal to the selected subcarrier.
Fig. 3A depicts an uplink subframe format using time division multiplexing
(TDM) in a DFT-S-OFDM wireless communication system. Fig. 3B depicts an uplink
subframe format using frequency division multiplexing (FDM) in a DFT-S-OFDM wireless
communication system.
Generally, ACK/NACK control information in a DFT-S-OFDM wireless
communication system is represented by either one bit, or a relatively small number of bits.
Consequently, the bit error rate (BER) may be somewhat degraded because of various factors
in a wireless channel. Typical multiplexing methods in the DFT-S-OFDM wireless
communication system include TDM (Fig. 3A) and FDM (Fig. 3B). Accordingly, a
transmitting UE in accordance with an embodiment will typically repeatedly transmit
ACK/NACK information to improve the BER.
Consider the case in which TDM is used by several UEs. In such a scenario
ACK/NACK information may be repeatedly transmitted in a long block (LB) allocated in a
subframe (e.g., LB #3 of Fig. 3A) over a specific frequency. Such an arrangement will
typically improve the BER characteristics.
Repeated transmissions over a specific frequency may be accomplished by
sequentially transmitting ACK/NACK information over a frequency band, or by mapping
ACK/NACK information to a specific sequence. DFT may optionally be performed on this
ACK/NACK information. If desired, ACK/NACK information may also be repeatedly
transmitted using block coding.
Consider now situations in which FDM is used to multiplex information
transmitted from multiple UEs. In such scenarios, ACK/NACK information may be
repeatedly transmitted in multiple LBs allocated in a subframe (e.g., LB #1 - LB #6 of Fig.
3B). Such an arrangement will also typically improve the BER characteristics. In some
cases, multiple ACK/NACK signals may be transmitted in response to downlink information
using multiple antennas. In an embodiment, the number of ACK/NACK signals is equal to
the number of CRCs inserted in the downlink data (as described above).
A UE may responsively transmit (uplink) a number of ACK/NACK signals
corresponding to the number of received CRCs for situations in which a CRC is inserted in
each portion of information transmitted through each of the antennas in the downlink. If the
UE transmits a plurality of ACK/NACK signals in this manner, the UE may also repeatedly
transmit the ACK/NACK signals a specific number of times. Such operations may be used to
improve BER characteristics of the transmitted ACK/NACK signals.
For example, consider that the number of ACK/NACK signals is M. The M
ACK/NACK signals may be denoted by ACK/NACKb ACK/NACK2,..., ACK/NACKm, and
the specific number of times is K. In this case, the ACK/NACK signals may be repeatedly
transmitted according to the following:
{(ACK/NACKli, ACK/NACKi.2, ... ACK/NACK,.k), {(ACK/NACK2_,,
ACK/NACK2-2,... ACK/NACK2-k).....(ACK/NACKm-i, ACK/NACKm-2, ... ACK/NACKm.
According to an alternative technique, ACK/NACK signals may be repeatedly
transmitted according to the following:
{(ACK/NACKm, ACK/NACK2-1,... ACK/NACKm-i), {(ACK/NACKi_2,
ACK/NACK2-2,... ACK/NACKm-2), .-., (ACK/NACKmc ACK/NACK2.k, - ACK/NACKm.
*»¦
Figs. 4A and 4B are block diagrams depicting techniques for reducing the
BER in a transmitting UE operating within a DFT-S-OFDM wireless communication system
according to an embodiment of the present invention. Consider first the situation in which
the transmitting end transmits multiple ACK/NACK signals using multiple antennas, hi such
a case, the transmitting end may transmit the ACK/NACK signals by performing block
coding on these signals using, for example, the techniques shown in Figs. 4A and 4B.
Referring now to Fig. 4A, a technique is shown in which prior to transmitting,
the ACK/NACK and CQI signals are first spread using separate DFTs. An alternative
technique is shown in Fig. 4B. hi this figure, the ACK/NACK signals are directly mapped to
a subcarrier without spreading these signals through a DFT. However, the embodiment of
Fig. 4B includes mapping the CQI signal to a subcarrier after spreading this signal using a
DFT.
Multiple ACK/NACK signals for improving the PAPR and BER
characteristics of ACK/NACK signals need not be directly transmitted, and instead may
alternatively be mapped to a specific sequence to be transmitted. According to one
technique, a specific sequence for mapping may be determined. A sequence may be selected
and a plurality of ACK/NACK signals mapped to the sequence. If desired, the sequence may
be selected as the specific sequence for mapping according to.its PAPR and BER
characteristics. Another option includes transmitting ACK/NACK signals after modulating
these signals using a conventional modulation technique such as BPSK or QPSK.
Fig. 5 is a block diagram depicting a method for selecting a subcarrier to be
allocated according to an embodiment of the present invention. This technique selects the
subcarrier based upon transmission status of the ACK/NACK. and CQI information and when
such information is transmitted.
Allocating a sufficiently large number of subcarriers to non-data-associated
control information in the uplink may reduce the number of subcarriers necessary to transmit
UE data. ACK/NACK and CQI information may be separately transmitted, as described
above. However, frequency resources may be efficiently allocated if subcarrier allocation is
also performed when both the ACK/NACK and CQI information is transmitted. This is
particularly the case where, without discriminating between the cases where only the
ACK/NACK information is transmitted, only the CQI information is transmitted or where the
ACK/NACK and CQI information are simultaneously transmitted.
Accordingly, a transmitting UE according to an embodiment of the present
invention may distinguish and receive ACK/NACK and CQI information, among non-data-
associated control information, to identify whether each of the ACK/NACK and CQI
information is transmitted. Based on this identification, the UE may allocate a subcarrier
suitable for each case in which only the ACK/NACK information is transmitted, or where
only the CQI information is transmitted, or where both the ACK/NACK and CQI information
are simultaneously transmitted. This embodiment distinguishes between ACK/NACK and
CQI information among non-data-associated control information to identify whether each of
the ACK/NACK and CQI information is transmitted. This embodiment efficiently manages
frequency resources, and permits allocation of increased amounts of frequency resources for
transmission, thereby achieving frequency diversity.
Advantages of various embodiments include the UE distinguishing
ACK/NACK and CQI information, among non-data-associated control information which is
not associated with data demodulation, and separately processing such information before it
is mapped to frequency resources. This allows a base station to easily process received
control information, even when the base station separately receives ACK/NACK and CQI
information from multiple UEs through the same resource block. Moreover, improvement of
the BER characteristics of the ACK/NACK information may be accomplished by repeatedly
transmitting the ACK/NACK information in the uplink over a specific time period when
FDM is employed, or over a specific frequency when TDM is employed.
When multiple ACK/NACK signals are transmitted, improvement of the
PAPR and/or BER characteristics may also be accomplished by performing processes on the
transmitted ACK/NACK signals. Examples of such signals include block coding, mapping to
a specific sequence, and modulation through BPSK or QPSK.
Allocating Frequency Resource
Additional alternative embodiments relate to allocating frequency resources
for ACK/NACK transmissions in uplink multi-carrier or single-carrier (SC) FDMA systems.
Fig. 6 shows an uplink subframe format. In this figure, a long block (LB) is used for data and
control information transmissions, and a short block (SB) is used for pilot and data
transmissions.
Uplink transmission by the UE may be classified into the following cases:
UE data, pilot, data-associated control;
UE data, pilot, data-associated control, non-data-associated
control; and
Pilot, non-data-associated control.
These cases may be multiplexed using, for example, the various multiplexing
techniques shown in Fig. 7 and Fig. 8. The subframe format of Fig. 6 includes multiplexing
data-associated control information and non-data-associated control information with UE
data, and simultaneously multiplexing non-data-associated control information of several
UEs.
In Fig. 7, although data-associated control information and UE data are
multiplexed, a predetermined time-frequency domain is decided for the transmission of non-
data-associated control information of several UEs. If UE data exists, non-data-associated
control information is shown transmitted on the band for the transmission of UE data, instead
of the band decided for the non-data-associated control information on which UE data is
transmitted. A benefit of this technique is to maintain the SC-FDMA characteristics.
As shown in Figs. 7 and 8, band allocations of UE data and non-data-
associated control are performed in the same manner. In particular, when the UE data
corresponds to localized allocation, the localized allocation is applied to the non-data-
associated control as well. However, ACK/NACK information among the non-data-
associated control information has a size of one bit and is therefore unable to be channel
coded. Consequently, iteration of the ACK/NACK information may be performed to obtain a
specific eiror rate.
Figs. 9A-9C depict embodiments which relate to allocating a frequency
resource for ACK/NACK signal transmission in the uplink of a SC-FDMA/OFDMA system,
and variations thereof. In general, there are two techniques for allocating a frequency
resource in the uplink. The first technique being a distributed method of arranging
transmission data with the same interval on entire frequency bands (Fig. 9A). The second
technique being a localized method of arranging transmission data on a specific frequency
band (Figs. 9B, 9C).
Although the ACK/NACK signal is typically one bit in size, iteration of this
signal may be performed to obtain a specific error rate. For example, consider that the
ACK/NACK signal obtained from iteration is transmitted via N resource units (RU). In
transmitting the ACK/NACK signal iterated using a localized method though N RUs, if the
ACK/NACK is smaller than a frequency resource occupied by the N RUs, the two additional
methods may also be implemented. One technique is to allocate an iterated ACK/NACK
signal to continuous frequency resources, while the other technique is to arrange the
AGK/NACK signal on N RUs using, for example, an even interval. Accordingly, techniques
for allocating frequency resources for ACK/NACK transmission may be summarized as
follows:
- Distributed;
- Localized;
- Pure localized; and
- Distributed within allocated frequency resources.
Multiple codeword ACK/NACK
Yet another embodiment relates to HARQ in a mobile communication system,
and more particularly, to an apparatus for transmitting ACK/NACK signal in a multiple
codeword (MCW) type MIMO wireless system. As will be described, this embodiment is
suitable for a wide scope of applications including, for example, transmitting the
ACK/NACK signal using multiple MCW type transmitting and receiving antennas.
In general, multiple transmitting and receiving antennas may be used to raise
the data rate in a mobile communication system. Data transmission using multiple antennas
may be accomplished using two primary techniques. First, data may be transmitted in a
transmit diversity format. In this case, although a data rate is not raised, a signal to noise
ratio (SNR) of a received signal is raised to enable stable operation. This is because the same
data is transmitted via several antennas. The second technique includes transmitting data in a
spatial multiplexing format. In this case, simultaneously transmitting several independent
data streams raises the data rate. The transmit diversity transmission is efficient in an area
having a low SNR, whereas the spatial multiplexing transmission is efficient in an area
having a high SNR.
Figs. 10A and 10B are block diagrams depicting SCW and MCW transmitting
terminals configured for use in a MIMO wireless mobile communication system. It is
understood that in some situations, a plurality of data streams can be simultaneously
transmitted. For instance, coding may be performed by one channel encoder, and then the
data is divided into a plurality of data streams. This technique is often referred to as
transmitting using a single codeword (SCW).
Fig. 11 is a block diagram of an ACK/NACK transmitting apparatus according
to an embodiment of the present invention. This example provides a technique for
transmitting multiple streams which includes individually coding a plurality of data streams
via a channel encoder, and then transmitting the encoded data streams via a plurality of
transmitting and receiving antennas. This technique is often referred to as transmitting using
a multiple codeword (MCW).
SCW techniques include coding one block which is then divided. Since one
CRC for error checking is attached to each block, a receiver would typically transmit only
one ACK/NACK signal. On the other hand, using MCW, several blocks are coded and then
turned into a data stream. If CRC is attached per block, the ACK/NACK signal should be
transmitted for each data stream.
In general, the MCW is able to obtain a data rate higher than that of the SCW.
Consequently, the MCW is commonly used despite the increase'of ACK/NACK information
to be transmitted. However, in situations in which the MCW transmits an ACK/NACK
signal for each data stream, a receiver should secure radio resources for a plurality of
ACK/NACK transmissions. This increase of control information decreases radio resources
for the data transmission, resulting in degraded system efficiency.
Various aspects and embodiments of the present invention will now be
described. In general, these examples include an apparatus for transmitting ACK/NACK
signals in MCW type MIMO wireless system. For example, an apparatus for transmitting
ACK/NACK signals in a MCW type MIMO wireless system by which a number of
ACK/NACK signals to be transmitted can be reduced by maintaining a high data rate MCW.
One aspect includes transmitting an ACK/NACK in a wireless communication
system using a plurality of MCW type transmitting and receiving antennas. Various
operations include generating a plurality of ACK/NACKs corresponding to a number of error
detection codes inserted in a plurality of data streams received via a plurality of antennas, and
generating an ACK/NACK by combining a plurality of the ACK/NACKs, and transmitting
the generated ACK/NACK via the antenna.
Another aspect includes generating a plurality of ACK/NACKs corresponding
to a number of error detection codes inserted in a plurality of data streams received via a
plurality of antennas, and grouping a plurality of the ACK/NACKs. The method further
includes generating one ACK/NACK per group by combining a plurality of the grouped
ACK/NACKs into a plurality of such groups, and transmitting the generated ACK/NACK
groups via the antenna.
One aspect includes, in the grouping operation, grouping a plurality of the
ACK/NACKs according to types of corresponding data streams.
Another aspect utilizes the error detection code as a CRC code.
Yet another aspect includes transmitting the received data streams for one
timeslot via a plurality of the transmitting antennas.
Still yet another aspect includes combining a plurality of the ACK/NACKs by
an AND operation.
In an embodiment, an apparatus for transmitting an ACK/NACK in a wireless
communication system using a plurality of MCW type transmitting and receiving antennas
includes an error checking unit generating a plurality of ACK/NACKs corresponding to a
number of error detection codes inserted into a plurality of data streams received via a
plurality of antennas. The apparatus further includes a signal combining unit generating one
ACK/NACK by combining a plurality of the ACK/NACKs, and a signal transmitting unit
transmitting the generated ACK/NACK via the antenna.
In another aspect, an apparatus includes a control unit grouping a plurality of
the ACK/NACKs, a signal combining unit generating one ACK/NACK per group by
combining a plurality of the grouped ACK/NACKs into a plurality of groups, and a signal
transmitting unit transmitting the generated ACK/NACK groups via the antenna.
According to an aspect, the control unit groups a plurality of the ACK/NACKs
according to the types of corresponding data streams.
One aspect utilizes the error detection code as an CRC code, and the received
data streams are transmitted for one timeslot via a plurality of the transmitting antennas, and
the signal combining unit combines a plurality of the ACK/NACKs by an AND operation.
Referring again to Fig. 11, a receiving terminal includes a plurality of antennas.
When independent data is transmitted via a plurality of antennas to achieve a high data rate,
the number of antennas of a receiving terminal should be equal to or greater than that of the
antennas of the transmitting terminal. Fig. 11 shows n antennas to indicate that n information
streams are received.
Information (e.g., n information in Fig. 11) received via a plurality of antennas
are decoded in correspondence to the channel coding technique performed by the transmitting
terminal. A CRC checking unit then performs an error check using CRC which is included in
each of the decoded information streams. As a result of performing this CRC checking, if an
error exists, the CRC checking unit generates a NACK. If there is no error, the CRC
checking unit generates an ACK. Accordingly, when n different information streams are
received in parallel, n ACK/NACKs will be transmitted. In this case, the n received data
streams may be assumed as data streams transmitted for one timeslot via n transmitting
antennas. If desired, the information streams within a certain timeslot may be simultaneously
processed.
Fig. 11 shows n ACK/NACKs inputted to a combiner to be combined into one
ACK/NACK signal. For example, n ACK/NACKs may be combined into one ACK/NACK.
An AND operation is carried out to combine these signals into one ACK/NACK. In
particular, consider n ACK/NACKs such as ACK/NACK1, ACK/NACK2, ..., ACK/NACKn.
The combined ACK/NACK can be expressed according to the following:
ACK/NACK (Combined) = ACK/NACK1 D ACK/NACK2 D... PI
ACK/NACKn,
where if data is successfully received, each of ACK/NACK1 to ACK/NACKn
can have a value of 1. Otherwise, each of these ACK/NACKs can have a value of 0.
If the combined ACK/NACK indicates 1, this could refer to the entire n data
as being successfully received. If the combined ACK/NACK indicates 0, this could refer to
at least one of the n data as not being successfully received. Consequently, a frequency
resource for control information transmission can be efficiently allocated.
Fig. 12 is a block diagram of an ACK/NACK transmitting apparatus according
to another embodiment of the present invention. In this embodiment, a control unit is added
to the configuration shown in Fig. 11, as well as a plurality of combiners.
In Fig. 12, n ACK/NACKs respectively generated by CRC checking units are
inputted to a control unit. The control unit then groups the inputted ACK/NACKs into a
plurality of groups. These groups can be classified according to a type of received data
stream. For instance, if a prescribed portion of data is important in checking a successful data
reception and needs to be separately processed, it can be separately grouped. Alternatively,
these ACK/NACKs can be divided into a prescribed number of groups to appropriately select
the size of control information to be transmitted regardless of the type of the received data.
As mentioned above, the grouped ACK/NACK signals are combined by a
plurality of combiners to generate one ACK/NACK signal per group. In general,
ACK/NACKs corresponding to a specific group may include a single ACK/NACK. In this
aspect, a corresponding ACK/NACK is processed in the same manner as other ACK/NACKs
having undergone the combining operation without passing through a separate operation for
the ACK/NACK signal combining.
Consider further that the number of groups selected by the above principle
may be equal to or smaller than m, and thus m ACK/NACKs may be obtained. The m
ACK/NACKs are inputted to a transmitting unit and then transmitted via an antenna.
The embodiments of Figs. 11 and 12 have been described with regard to the
error detection code implemented using CRC code. Alternatively, a random error detection
code that is a signal requested by a receiving terminal may be used to be informed whether a
data transmission is successful.
Various embodiments enable a receiving terminal to transmit ACK/NACK at
the SCW level despite using MCW having a data rate that is higher than that of the SCW.
Alternatively, if transmission of the n data streams falls below a certain critical count, an
. ACK/NACK indicating a presence or non-presence of a transmission success for each of the
n data streams can be transmitted without being combined instead of repeating transmissions
of the entire n data streams. Alternatively, consider the situation in which transmission of
specific data fails a certain number of times on the assumption that a plurality of received
data streams can be individually discriminated. ACK/NACK information for indicating a
presence or non-presence of transmission success of the specific data stream is independently
transmitted without combining and the remainder of ACK7NACK signals are combined and
transmitted.
It is understood that an ACK/NACK is an example of control information
which indicates whether data transmitted by a transmitting terminal is successfully received
by a receiving terminal. ACK/NACK is commonly used for HARQ. However, a random
signal, for example, performing the above-noted functions may be used as a replacement for
ACK/NACK.
Subcarrier Mapping in Uplink
Various additional embodiments relate to subcarrier mapping in the uplink. In
particular, such embodiments include arranging transmission data in a frequency resource
allocated to the uplink in a wireless communication system using a plurality of subcarriers
and a transmitter implementing the same.
Fig. 13 depicts localized allocation of a number of subcarriers. In this figure,
localized allocation refers to user data that is transmitted via a prescribed number of
subcarriers, distributed adjacent to a predetermined band, among the entire band of a
frequency resource allocated for the uplink. User data is transmitted via subcarriers on a
predetermined band only by inputting 0 to the remaining subcarriers.
According to the localized allocation, only a partial band of an uplink
frequency resource is used. Yet, if transmission data is transmitted by a resource unit
including a predetermined number of subcarriers, the transmission data tends to be
intensively arranged in a predetermined area within resource units consecutively allocated to
a partial band of the frequency resource.
Fig. 13B depicts distributed allocation of a number of subcarriers. In this
figure, distributed allocation refers to user data transmitted via subcarriers equally distributed
across entire bands of a frequency resource allocated for the uplink. By inputting 0 to the
remaining subcarriers, the system can transmit the user data using only the distributively
allocated specific subcarriers.
The distributed allocation can distributively transmit the data across the entire
bands of the uplink frequency resource to raise frequency diversity. So, it is advantageous
that the distributed allocation is strong against channel influence. However, as a pilot interval
in transmitting a pilot using a short block gets wider than that in transmitting a pilot using a
long block, channel estimation performance may be degraded.
By way of overview, various embodiments include a method of arranging
subcarriers for retransmission data distributively within an allocated partial band and a
transmitter supporting the same. Channel influence may be minimized using localized
allocation.
One aspect includes arranging subcarriers for transmission data distributively
and a transmitter supporting the same. A predetermined number of the subcarriers are bound
together to be distributively arranged according to localized allocation.
Another embodiment relates to a method of arranging subcarriers in the uplink,
in which the subcarriers for data transmission are arranged in a frequency resource allocated
for the uplink. One operation includes arranging the subcarriers for data transmission in a
local band of the frequency resource allocated for the uplink, such that the subcarriers are
distributed with an equal space for a whole part of the local band.
According to one feature, the transmission data is a control signal repeatedly
coded with prescribed bits.
In another feature, the transmission data is transmitted via N (N = 1, 2, 3, ...)
resource units, each having a prescribed number of subcarriers, and wherein the subcarriers
are arranged in a manner of arranging theN resource units in the local band of the frequency
resource allocated for the uplink and distributing the subcarriers with the equal space across a
whole band occupied by the N resource units.
In another aspect, a method of arranging subcarriers in the uplink, in which the
subcarriers for data transmission are arranged in a frequency resource allocated for the uplink,
includes grouping the subcarriers for the data transmission by at least two of the subcarriers
across a whole band of the frequency resource allocated for the uplink, wherein the grouped
subcarriers are distributed with an equal space.
Another feature relates to the transmission data transmitted via N (N = 1, 2, 3,
...) resource units, each having a prescribed number of subcarriers, and wherein the
subcarriers are arranged in a manner of distributing the N resource units in the whole band of
the frequency resource allocated for the uplink with the equal space. The method further
includes grouping the subcarriers by at least two of the subcarriers, and arranging the grouped
subcarriers within each of theN resource units.
In yet another aspect, an apparatus includes a subcarrier arranging module
arranging the subcarriers for the data transmission in a local band of the frequency resource
allocated for the uplink, wherein the subcarriers are distributed with an equal space for a
whole part of the local band.
In one feature, the transmission data is transmitted via N (N = 1, 2, 3, ...)
resource units, each having a prescribed number of the subcarriers, and wherein the
subcarriers are arranged in a manner of arranging the N resource units in the local band of the
frequency resource allocated for the uplink and distributing the subcarriers with the equal
space across a whole band occupied by the N resource units.
In another aspect, a transmitting apparatus for arranging subcarriers in the
uplink includes a subcarrier arranging module grouping the subcarriers for the data
transmission by at least two of the subcarriers across a whole band of the frequency resource
allocated for the uplink, wherein the grouped subcarriers are distributed with an equal space.
Fig. 14 is a block diagram depicting a method for uplink transmission using
OFDM. At block 210, a high data Tate data stream (or data symbol) is inputted in series and
converted to a plurality of data streams having slow data rates via a serial to parallel
converter. Each of the parallel-converted data streams is multiplied by a corresponding
subcarrier through a subcarrier mapper (block 220), and then transformed into a time-domain
signal by IDFT (block 230). Block 240 inserts a cyclic prefix in the time-domain signal for
preventing channel interference. The signal is converted to a serial signal and then
transmitted to a receiving terminal (block 250).
It is understood that in a system performing modulation using a plurality of
orthogonal subcarriers, OFDMA refers to the situation in which a multiple access method is
accomplished by providing portions of available subcarriers to different users. OFDMA
provides different users with frequency resources, such as subcarriers. Since the frequency
resources are independently provided to a plurality of users, they are not overlapped, with
each other.
Since orthogonality is maintained between subcarriers, a high data rate can be
obtained. A possible problem that may arise relates to the peak to average power ratio
(PAPR). To minimize or effectively eliminate this problem, spreading is carried out in the
frequency domain using a DFT matrix. This operation is typically performed before the
generation of an OFDM signal. The result of the spreading is modulated by OFDM to obtain
a single carrier transmission. This situation may be referred to as DFT-S-OFDMA.
Fig. 15 is a flowchart depicting the generation of a transmission signal
according to DFT-S-OFDMA. The technique is similar in many respects to that which is
shown in Fig. 1, such that blocks 310 - 340 generally correspond to blocks 110-140 of Fig. 1.
A distinction is that cyclic prefix insertion (block 350) is shown occurring prior to the
parallel/serial conversion of block 360.
In a multi-carrier system using OFDMA or DFT-S-OFDM, user equipment
data, pilot, control information, and the like, are transmitted in the uplink. If the user
equipment data is transmitted in the uplink, corresponding control information is transmitted
in the downlink. Using the corresponding control information, a transmission band is
allocated or a data transport format is decided.
There are two general types of pilot signals. A CQ pilot is used to measure
channel quality to perform UE scheduling and adaptive modulation and coding. A data pilot
may also be used for channel estimation and data demodulation in data transmission. The
data pilot is the pilot transmitted on a corresponding domain. Control information may
include data-associated control information and non-data-associated control information, as
described above. The above-noted UE data, pilot, and control information may be
transmitted via a subframe having a predetermined structure. An example includes a FDD
sub frame for the uplink proposed by 3 GPP LTE. A suitable subframe is depicted in Fig. 3 A.
Referring back to Fig. 3 A, a cyclic prefix (CP) is shown inserted between the
respective blocks to avoid inter-block interference. In this arrangement, the long block (LB)
is usable for transmission of uplink data or control information, and the short block (SB) is
usable for transmission of uplink data or a pilot
One method for multiplexing the subframe first includes multiplexing the UE
data, pilot, and data-associated-control information. Another method for multiplexing
includes multiplexing the UE data, pilot, data demodulation associated control information,
and data demodulation non-associated control information. A third method for multiplexing
includes multiplexing the pilot and data demodulation non-associated control information.
Referring back to Fig. 7, data demodulation associated control information and
data demodulation non-associated control information for a specific user are shown
multiplexed with UE data of a corresponding user, and simultaneously, data demodulation
non-associated control information for other users is multiplexed together. This results in
each resource block including the same kind of uplink data.
Referring back to Fig. 8, data demodulation associated control information for
a specific user and UE data are multiplexed, but data demodulation non-associated control
information for multiple users including the specific user is transmitted via a separately
provided predetermined time-frequency domain (area indicated by slashes in Fig. 8). Various
kinds of data carried by the subframes, such as that which is shown in Figs. 7 and 8, may be
multiplexed in the time domain to maintain the advantage of the DFT-S-OFDM having low
PAPR.
Since UE data for a specific user and data demodulation non-associated
control information are multiplexed and transmitted for the same subframe, it is common for
the same kind of frequency allocation to be applied to the UE data and the data demodulation
non-associated control information. In particular, if localized allocation is applied to the UE
data, it should be applied to the data demodulation non-associated control information as well.
As previously described, the ACK/NACK may be represented by a relatively
few number of bits. The UE, for example, may repeatedly transmit ACK/NACK for error
rate enhancement. This may be accomplished using, for example, the various techniques
previously described with regard to Figs. 3A and 3B.
Note that the repeated ACK/NACK can be transmitted via a resource unit that
is a bundle of a prescribed number of consecutive subcarriers. The resource unit generally
includes 25 long block frequency intervals, which does not appear to be a significant
limitation. Alternatively, the resource unit may include long block frequency intervals of
other lengths (e.g., 15,12,10, and the like). The size of a normal resource unit can be
represented as:
RU = 25*15 KHz(LB) = 375 KHz.
Hence, the localized allocation among the above-described frequency
allocation techniques is characterized in that N resource units are consecutively allocated to a
partial band. The distributed allocation among the described frequency allocation methods is
characterized in that N resource units are discontinuously and equally allocated across entire
bands.
In localized allocation, a frequency resource allocated to subcarriers for
ACK/NACK signal transmission is smaller than a frequency resource occupied by N resource
units. As an example, Fig. 16 shows a distribution of subcarriers used for resource unit and_
ACK/NACK transmission. In particular, N resource units are consecutively allocated to a
partial band of an uplink frequency resource. The subcarriers used for repeated transmission
of ACK/NACK signal among subcarriers included in the N resource units can be intensively
arranged on a specific band (central band in Fig. 16) of the frequency resource occupied by
the N resource units. This case is referred to as pure localized allocation.
As noted above, localized allocation is vulnerable to channel influence since .
data is transmitted on an adjacent channel. Pure localized allocation is more vulnerable to '
channel influence since the subcarriers of the transmission object included in the N resource
units are intensively located on a specific band, as well as the N resource units being adjacent
to each other.
To improve these vulnerabilities, enhanced localized allocation (distributed
within allocated frequency resources) may be utilized. Fig. 17 provides an example of a
subcarrier arrangement using enhanced localized allocation. This technique applies
distributed allocation to the subcarriers of the transmission object included in the N resource
units, while applying localized allocation to the N resource units. In particular, subcarriers
actually used for transmission of ACK/NACK signal are equally spaced and discontinuously
arranged across the entire frequency resource.
Fig. 18 shows a distribution of subcarriers used for ACK/NACK signal
transmission. The distributed allocation may be used to achieve frequency diversity. When a
pilot is carried by a short block, a pilot interval becomes wider than when a long block is
used. Such an arrangement may not be preferable since channel estimation performance may
be degraded. An enhanced distributed allocation capable of enhancing channel estimation
performance may be achieved by grouping subcarriers for ACK/NACK signal transmission
into a plurality of groups, each of which includes at least two subcarriers. These groups are
then arranged instead of arranging the individual subcarriers.
Figs. 19A and 19B depict a subcarrier arrangement using enhanced distributed
allocation, in which a pair of subcarriers is configured as a group. In Fig. 19 A, since each
subcarrier carries an ACK/NACK signal using a long block, a frequency interval (e.g., 15
KHz) amounting to the long block exists between a pair of the subcarriers configuring the
corresponding group.
In order to transmit an ACK/NACK signal to a receiving terminal, pilot
information for matching synchronization between transmitting and receiving terminals
should be transmitted to the receiving terminal. Since it is unnecessary to transmit the pilot
information for each subcarrier, the present embodiment implements one pilot that is
transmitted for a pair of the grouped subcarriers. The pilot information is carried by a short
block. Since a frequency band (e.g., 30 KHz) of a short block is generally twice as wide as
that of a long block, it coincides with the technique that otfe pilot is transmitted for each pair
of the subcarriers for ACK/NACK signal transmission.
Fig. 19B shows frequency resource allocation of subcarriers for the pilot
information transmission. Consider a grouping of subcarriers for ACK/NACK signal
transmission by a three-subcarrier unit, a frequency band (15 KHz * 3 = 45 KHz) occupied
by one group is not equal to a frequency band (30 KHz) occupied by the subcarriers for pilot
transmission. Because of this, a gap of 30 KHz between the groups may be necessary (Fig.
20A). Since the subcarriers for pilot information transmission, as shown in Fig. 20B, should
be arranged for each 60 KHz, channel estimation performance using a pilot is degraded rather
than the case of configuring a group with a pair of subcarriers.
As mentioned in the foregoing description, the enhanced localized allocation
or the enhanced distributed allocation is typically carried out by a suitable subcarrier mapper
(e.g., block 220 of Fig. 14) of the OFDM transmitting terminal or the subcarrier mapper of
the OFDMA transmitting terminal (e.g., block 330 of Fig. 15). Alternatively, the enhanced
localized allocation or the enhanced distributed allocation can be carried out by a subcarrier
arranging module responsible for each frequency resource allocation.
A benefit of localized allocation permits efficient use of frequency resources
and arranges subcarriers for transmission data within the locally allocated resource units.
Hence, such an arrangement is protected against channel influence in a manner that is greater
than existing systems. Another benefit relates to the distributed allocation to avoid channel
influence. This embodiment binds a predetermined number of subcarriers for transmission,
and arranges the subcarriers distributively. Hence, compared to conventional systems,
degradation of channel estimation is reduced.
Although embodiments of the present invention may be implemented using
the exemplary series of operations described herein, additional or fewer operations may be
performed. Moreover, it is to be understood that the order of operations shown and described
is merely exemplary and that no single order of operation is required.
The foregoing embodiments and advantages are merely exemplary and are not
to be construed as limiting the present invention. The present teaching can be readily applied
to other types of apparatuses and processes. The description of the present invention is
intended to be illustrative, and not to limit the scope of the claims. Many alternatives,
modifications, and variations will be apparent to those skilled in the art.
Claims
What is claimed is:
1. A method for encoding uplink acknowledgments to downlink transmissions,
the method comprising:
receiving a plurality of data blocks, wherein each of the data blocks include an
associated cyclic redundancy check (CRC);
determining received status for each of the data blocks by checking the CRC of each
of the data blocks; and
generating a response sequence which indicates the received status of all of the data
blocks.
2. The method according to claim 1, wherein the data blocks comprise a primary
transport block and a secondary transport block.
3. The method according to claim 1, wherein the response sequence is a discrete
response sequence.
4. The method according to claim 1, further comprising:
generating the response sequence as a single response sequence which indicates the
received status of all of the data blocks.
5. The method according to claim 1, wherein the receiving of the data blocks is
from a Node B.
6. The method according to claim 1, wherein the status is either an
acknowledgment (ACK) which identifies a data block which has been received without error,
or a negative acknowledgment (NACK) which identifies a data block which has been
received with an error.
7. The method according to claim 1, further comprising:
modulating the response sequence using QPSK modulation.
8. The method according to claim 1, further comprising:
transmitting the response sequence to a Node B.
9. The method according to claim 1, wherein the downlink transmissions comprise
multiple input multiple output (MTMO) transmissions.
10. The method according to claim 9, further comprising:
receiving the data blocks in parallel.
11. The method according to claim 1, wherein the downlink transmissions comprise
time division duplex (TDD) transmissions.
12. The method according to claim 11, further comprising:
sequentially receiving the data blocks.
13. The method according to claim 11, further comprising:
receiving the data blocks in parallel.
14. A method for receiving encoded uplink acknowledgments to downlink
transmissions, the method comprising:
transmitting in parallel a plurality of data blocks, wherein each of the data blocks
include an associated cyclic redundancy check (CRC); and
receiving a single response sequence which indicates received status of all of the data
blocks.
15. The method according to claim 14, wherein the data blocks comprise a
primary transport block and a secondary transport block.
16. The method according to claim 14, wherein the transmitting of the data blocks
is from a Node B.
17. The method according to claim 14, wherein the status is either an
acknowledgment (ACK) which identifies a data block which has been received without eixor,
or a negative acknowledgment (NACIC) which identifies a data block which has been
received with an error.
18. The method according to claim 14, wherein the response sequence has been
modulated using QPSK modulation.
19. The method according to claim 14, wherein the downlink transmissions
comprise multiple input multiple output (MIMO) transmissions.
20. The method according to claim 14, wherein the downlink transmissions
comprise time division duplex (TDD) transmissions.
21. A portable device for encoding uplink acknowledgments to downlink
transmissions, the portable device comprising:
a receiver configured to receive a plurality of data blocks, wherein each of the data
blocks include an associated cyclic redundancy check (CRC);
a processor configured to determine received status for each of the data blocks by
checking the CRC of each of the data blocks; and
a transmitter for transmitting a response sequence which indicates the received status
.of all of the data blocks.
22. The portable device according to claim 21, wherein the data blocks comprise a
primary transport block and a secondary transport block.
23. The portable device according to claim 21, wherein the response sequence is a
discrete response sequence.
24. The portable device according to claim 21, wherein the processor is further
configured to:
generate the response sequence as a single response sequence which indicates the
received status of all of the data blocks.
25. The portable device according to claim 21, wherein the receiver is further
configured to:
receive the data blocks from a Node B.
26. The portable device according to claim 21, wherein the status is either an
acknowledgment (ACK) which identifies a data block which has been received without error,
or a negative acknowledgment (NACK) which identifies a data block which has been
received with an error.
27. The portable device according to claim 21, wherein the processor is further
configured to:
modulate the response sequence using QPSK modulation.
28. The portable device according to claim 21, wherein the transmitter is further
configured to:
transmit the response sequence to a Node B.
29. The portable device according to claim 21, wherein the downlink
transmissions comprise multiple input multiple output (MDviO) transmissions.
30. The portable device according to claim 29, wherein the receiver is further
configured to:
receive the data blocks in parallel.
31. The portable device according to claim 21, wherein the downlink transmissions
comprise time division duplex (TDD) transmissions.
32. The portable device according to claim 31, wherein the receiver is further
configured to:
sequentially receive the data blocks.
33. The portable device according to claim 31, wherein the receiver is further
configured to:
receive the data blocks in parallel.
34. A transmitting entity operable in a wireless communication system and
configured to receive encoded uplink acknowledgments to downlink transmissions, the
transmitting entity comprising:
a transmitter for transmitting in parallel a plurality of data blocks, wherein each of the
data blocks include an associated cyclic redundancy check (CRC); and
a receiver for receiving a single response sequence which indicates received status of
all ofthe data blocks.
35. The transmitting entity according to claim 34, wherein the data blocks
comprise a primary transport block and a secondary transport block.
36. The transmitting entity according to claim 34, wherein the transmitter is
further configured to:
transmit the data blocks from a Node B.
37. The transmitting entity according to claim 34, wherein the status is either an
acknowledgment (ACK) which identifies a data block which has been received without error,
or a negative acknowledgment (NACK) which identifies a data block which has been
received with an error.
_ 38. The transmitting entity according to claim 34, further comprising:
a modulator for modulating the response sequence using QPSK modulation.
' 39. The transmitting entity according to claim 34, wherein the downlink
transmissions comprise multiple input multiple output (MIMO) transmissions.
. 40. The transmitting entity according to claim 34, wherein the downlink
transmissions comprise time division duplex (TDD) transmissions.
41. A method for encoding uplink acknowledgments to downlink transmissions,
the method comprising:
receiving a plurality of data blocks, wherein each ofthe data blocks include an
associated cyclic redundancy check (CRC);
determining received status for each of the data blocks by checking the CRC of each
of the data blocks;
generating a response bit according to the status;
mapping the response bit to a fixed length sequence to generate a mapped sequence;
transmitting the mapped sequence in an uplink transmission; and
repeating the mapping and transmitting for a predetermined time period.
42. The method according to claim 41, further comprising:
generating response bits; and
mapping the response bits to the fixed length sequence to generate the mapped
sequence.
A portable device, such as a mobile terminal or user equipment fur encoding uplink acknowledgments to downlink transmissions. The portable device includes a receiver configured to received a plurality of data blocks, such that each of the data blocks include an associated cyclic redundancy cheek (CRC), and a processor configured to determine received status for each of the data blocks by checking the CRC of each of the data blocks. The portable device further includes a transmitter for transmitting a response sequence which indicates the received status of all of the data blocks.

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http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=5M4BtUm0s5e17yyxbNhKtg==&loc=wDBSZCsAt7zoiVrqcFJsRw==


Patent Number 269232
Indian Patent Application Number 4935/KOLNP/2008
PG Journal Number 42/2015
Publication Date 16-Oct-2015
Grant Date 12-Oct-2015
Date of Filing 05-Dec-2008
Name of Patentee LG ELECTRONICS INC.
Applicant Address 20, YEOUIDO-DONG, YEONGDEUNGPO-GU, SEOUL
Inventors:
# Inventor's Name Inventor's Address
1 KIM, BONG HOE LG INSTITUTE, HOGYE 1(IL)-DONG, DONGAN-GU, ANYANG-SI, GYEONGGI-DO 431-749
2 KIM, KI JUN LG INSTITUTE, HOGYE 1(IL)-DONG, DONGAN-GU, ANYANG-SI, GYEONGGI-DO 431-749
3 KIM, EUN SUN LG INSTITUTE, HOGYE 1(IL)-DONG, DONGAN-GU, ANYANG-SI, GYEONGGI-DO 431-749
4 YOON, SUK HYON LG INSTITUTE, HOGYE 1(IL)-DONG, DONGAN-GU, ANYANG-SI, GYEONGGI-DO 431-749
5 SEO, DONG YOUN LG INSTITUTE, HOGYE 1(IL)-DONG, DONGAN-GU, ANYANG-SI, GYEONGGI-DO 431-749
6 LEE, JUNG HOON LG INSTITUTE, HOGYE 1(IL)-DONG, DONGAN-GU, ANYANG-SI, GYEONGGI-DO 431-749
7 JUNG, IN JAE LG INSTITUTE, HOGYE 1(IL)-DONG, DONGAN-GU, ANYANG-SI, GYEONGGI-DO 431-749
8 AHN, JOON KUI LG INSTITUTE, HOGYE 1(IL)-DONG, DONGAN-GU, ANYANG-SI, GYEONGGI-DO 431-749
9 KIM, HAK SEONG LG INSTITUTE, HOGYE 1(IL)-DONG, DONGAN-GU, ANYANG-SI, GYEONGGI-DO 431-749
10 YUN, YOUNG WOO LG INSTITUTE, HOGYE 1(IL)-DONG, DONGAN-GU, ANYANG-SI, GYEONGGI-DO 431-749
PCT International Classification Number H04L 1/18,H04Q 7/38
PCT International Application Number PCT/KR2007/002944
PCT International Filing date 2007-06-18
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10-2006-0054564 2006-06-16 Republic of Korea
2 10-2006-0054563 2006-06-16 Republic of Korea
3 60/805,059 2006-06-16 Republic of Korea
4 10-2006-0074636 2006-08-08 Republic of Korea