U.S. patent application number 12/698233 was filed with the patent office on 2010-06-03 for method and apparatus for controlling transmitting, receiving, and re-transmission.
This patent application is currently assigned to Fujitsu Limited. Invention is credited to Shunji Miyazaki, Kazuhisa Obuchi, Tetsuya Yano.
Application Number | 20100138716 12/698233 |
Document ID | / |
Family ID | 34747527 |
Filed Date | 2010-06-03 |
United States Patent
Application |
20100138716 |
Kind Code |
A1 |
Obuchi; Kazuhisa ; et
al. |
June 3, 2010 |
METHOD AND APPARATUS FOR CONTROLLING TRANSMITTING, RECEIVING, AND
RE-TRANSMISSION
Abstract
The present invention relates to a method and apparatus that are
capable of executing the error correction decoding process while
controlling the increase in the amount of data that is stored in
the receiving apparatus. There is provided a transmitting apparatus
for transmitting the data to a receiving apparatus to execute the
error correction decoding process using, for example, the received
data and the re-transmitted data, comprising a transmitting data
generating means for generating a first transmitting data by
executing the rate matching process to a first part of the error
correction coded data and generating a second transmitting data
including at least the data not included in the first part by
executing the rate matching process on the basis of the error
correction coded data, and a transmitting means for executing the
transmission of the second transmitting data as the re-transmission
after the transmission of the first transmitting data.
Inventors: |
Obuchi; Kazuhisa; (Yokohama,
JP) ; Yano; Tetsuya; (Yokosuka, JP) ;
Miyazaki; Shunji; (Yokosuka, JP) |
Correspondence
Address: |
HANIFY & KING PROFESSIONAL CORPORATION
1055 Thomas Jefferson Street, NW, Suite 400
WASHINGTON
DC
20007
US
|
Assignee: |
Fujitsu Limited
Kawasaki-shi
JP
|
Family ID: |
34747527 |
Appl. No.: |
12/698233 |
Filed: |
February 2, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10963811 |
Oct 14, 2004 |
7685504 |
|
|
12698233 |
|
|
|
|
Current U.S.
Class: |
714/751 ;
714/E11.032; 714/E11.131 |
Current CPC
Class: |
H04L 1/1819 20130101;
H04L 1/0068 20130101; H04L 1/1845 20130101; H04L 1/0075 20130101;
H04L 1/08 20130101 |
Class at
Publication: |
714/751 ;
714/E11.032; 714/E11.131 |
International
Class: |
H04L 1/18 20060101
H04L001/18; G06F 11/10 20060101 G06F011/10; G06F 11/14 20060101
G06F011/14; H03M 13/05 20060101 H03M013/05 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 27, 2004 |
JP |
2004-52628 |
Claims
1. A receiving apparatus for executing the error correction
decoding process by using data obtained by combining received data
and re-transmitted data, comprising: a storage unit for storing the
first received data, and a controlling unit combining the data read
from the storage unit with received data transmitted in the
re-transmission other than the particular re-transmission and
controlling the storage of the combined data to the storage unit,
wherein said controlling unit is capable of combining the data read
from the storage unit with received data transmitted in the
particular re-transmission without storing the combined data within
the storage unit.
2. A receiving apparatus to execute an error correction decoding
process based on data obtained by combining received data and
re-transmitted data, comprising: a storage unit for storing the
first received data; and a control unit to execute the control, for
the received data in the re-transmission other than the particular
re-transmission, to combine the data read from the storage unit
with the received data and to store the combined data to the
storage unit, and wherein the received data in the particular
re-transmission is combined with the data read from the storage
means with the received data, to store the data part corresponding
to the data stored by the storage unit among the combined data to
the storage unit but not to store the data part not corresponding
to the data stored by the storage unit to the storage unit.
3. The receiving apparatus according to claim 2, further
comprising: a particular re-transmission detecting unit for
determining the particular re-transmission based on any of the
contents notified from a base station, the number of times of
transmission of the NACK signal, the number of times of reception,
and passage of time from the first reception.
4. The receiving apparatus according to claim 2, wherein the
receiving apparatus is a mobile station used in the mobile
communication system supporting the HSDPA, and whether the
transmission is the particular re-transmission or not is determined
by a particular re-transmission detecting unit for determining the
particular re-transmission with the information notified from a
base station via the HS-SCCH.
5. A receiving apparatus for executing the error correction
decoding process by using data by combining the received data
stored in a storage unit and the re-transmitted data, comprising: a
determining unit for determining whether the re-transmission is the
last re-transmission or not; and a control unit to control the
storage unit to store the combined data of the data re-transmitted
by the last re-transmission when the determining unit determines
the re-transmission is not the last re-transmission and to control
the storage unit not to store the combined data of the data
re-transmitted by the last re-transmission when the determining
unit determines the re-transmission is the last re-transmission.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 10/963,811, filed Oct. 14, 2004, the entire disclosure of
which is incorporated by reference herein.
FIELD OF THE INVENTION
[0002] The present invention relates to a transmitting apparatus, a
receiving apparatus, and a re-transmission control method. More
specifically, the present invention relates to a radio base station
and a mobile station in a mobile radio communication system.
BACKGROUND OF THE INVENTION
[0003] Standardization of the W-CDMA (UMTS) system, which is one of
the third generation mobile communication system, is now under
development by the 3GPP (3.sup.rd Generation Partnership Project).
As a theme of standardization, the HSDPA (High Speed Downlink
Packet Access) which can provide a maximum transmission velocity of
about 14 Mbps for the downlink is specified.
[0004] The HSDPA employs an adaptive modulation and coding (AMC)
system which includes, for example, a QPSK modulation method and a
16-level QAM method that are switched adaptively in accordance with
the radio communication environment between the base station and
mobile station.
[0005] Moreover, the HSDPA also adopts the H-ARQ (Hybrid Automatic
Repeat request) system. When a mobile station has detected an error
in the receiving data received from the base station, the data is
re-transmitted from the base station responding to the request from
the mobile station, while the mobile station executes the error
correction decoding process using both received data and the data
received from the re-transmission. In the H-ARQ, as described
above, if an error is detected, the gain of the error correction
decoding is raised and the number of times of re-transmission is
controlled by effectively utilizing the received data.
[0006] The major radio channels used for the HSDPA include the
HS-SCCH (High Speed-Shared Control Channel), HS-PDSCH (High
Speed-Physical Downlink Shared Channel), and HS-DPCCH (High
Speed-Dedicated Physical Control Channel).
[0007] The HS-SCCH and the HS-PDSCH are shared channels in the
downlink direction (i.e., the direction toward a mobile station
from a base station), and the HS-SCCH is a control channel for
sending various parameters of data transmitted by the HS-PDSCH. The
parameters, such as the modulation information which indicates the
modulation method used for transmission by the HS-PDSCH, number of
spreading codes assigned (number of codes), and information such as
the pattern of the rate matching for the transmitting data may all
be considered.
[0008] Meanwhile, the HS-DPCCH is an dedicated control channel in
the uplink direction (i.e., the direction toward a base station
from a mobile station) and is used to transmit the ACK signal and
NACK signal to the base station from the mobile station in
accordance with the acknowledgment or non-acknowledgment of
reception of the data received via the HS-PDSCH. If a mobile
station has failed to receive the data (the CRC error is detected
in the receiving data or the like), the base station executes the
re-transmission control because the NACK signal is transmitted from
the mobile station or neither the ACK signal nor the NACK signal is
received by the base station.
[0009] Moreover, the HS-DPCCH may also be used by the mobile
station which measured the receiving quality of the signal received
from the base station to transmit the result of the measurement to
the base station as the CQI (Channel Quality Indicator). The base
station determines the environment of the radio communication on
the basis of the received CQI. When the communication environment
is good, the modulation method is switched to the method for
transmitting the data at the higher transmission rate. If the
environment is not as good, on the contrary, the modulation method
is switched to the method for transmitting the data at a lower
transmission rate (namely, adaptive modulation is executed).
[0010] "Channel Format"
[0011] Next, a channel format in the HSDPA will be described
below.
[0012] FIG. 1 is a diagram illustrating a channel format in the
HSDPA. The W-CDMA introduces the code dividing multiplex system and
each channel is therefore separated with the spreading code.
[0013] The channels not yet described will be described briefly
first.
[0014] CPICH (Common Pilot Channel) and P-CCPCH (Primary Common
Control Physical Channel) are respectively common channels in the
downlink direction.
[0015] The CPICH is a channel used by a mobile station for
estimation of channel condition, searching of cells, the timing
reference of the other downlink physical channels in the same cell,
and the channel used for transmitting the pilot signal. The P-CCPCH
is the channel for transmitting the broadcasting information.
[0016] Next, the timing relationship of channels will be described
with reference to FIG. 1.
[0017] As illustrated, one frame (10 ms) is formed based on 15
slots in each channel. As described previously, since the CPICH is
used as a reference channel, the top of frames of the P-CPICH and
HS-SCCH channels are matched with the top of frame of the CPICH
channel. Here, the top of frame of the HS-PDSCH channel is delayed
by two slots from the HS-SCCH channel. This may be done to realize
demodulation of the HS-PDSCH channel using the demodulating method
that corresponds to the received modulation type after the mobile
station has received the modulation information via the HS-SCCH
channel. Moreover, the HS-SCCH and HS-PDSCH channels may form one
sub-frame with three slots.
[0018] The HS-DPCCH channel is not synchronized with the CPICH
channel but this channel is provided for the uplink direction and
is based on the timing generated in the mobile station.
[0019] The channel format of the HSDPA channel has been briefly
described above. Next, the processes up to transmission of the
transmitting data via the HS-PDSCH channel will be described with
reference to the block diagram.
[0020] "Structure of Base Station"
[0021] FIG. 2 illustrates a structure of a base station supporting
the HSDPA channel.
[0022] In FIG. 2, the reference numeral 1 designates a CRC
attachment unit; 2, a code block segmentation unit; 3, a channel
coding unit; 4, a bit separating unit; 5, a rate matching unit; 6,
a bit collecting unit; 7, a modulating unit.
[0023] Next, operations of each block will be described.
[0024] The transmitted data transmitted via the HS-PDSCH channel
(data accommodated within one sub-frame of the HS-PDSCH channel in
FIG. 1) is first subjected to the CRC arithmetic process in the CRC
attachment unit 1 and the result of the arithmetic operation is
added to the last part of the transmitting data. The transmitting
data to which the result of CRC arithmetic operation is added may
then be inputted to the code block segmentation unit 2 and is then
segmented into a plurality of blocks. This process is required to
shorten the data length in unit of the error correction coding,
considering the load of decoding process in the receiving side.
When the data length exceeds the predetermined length, the code
block is equally segmented into a plurality of blocks. An integer 2
or larger may be selected as the number of segmentations but the
number of segmentations 2 may be selected to simplify the
description. If the data length is rather short, segmentation of
the block may be unnecessary.
[0025] The segmented and transmitted data are respectively
processed as the object data of the individual error correction
encoding process in the channel coding unit 3. In other words, the
error correction encoding process is executed for the segmented
first block and second block. As an example of the channel encoding
process, a turbo encoding process may be used.
[0026] Here, the turbo encoding process will be described briefly.
In an exemplary turbo encoding process, when the data is defined as
U, the data U' obtained by the convolutional encoding of the data
U, and the data U'' obtained by the convolutional encoding of the
data U after the interleave (re-arrangement) process of the data U
may be outputted. Here, the data may be referred to as the
systematic bits and may be understood, in the turbo decoding
process, as the data used in two element decoders and the data
having a higher degree of importance because the application
frequency is high. On the other hand, the data U' and U'' are
parity bits. These bits are data used in one of the two element
decoders and have a degree of importance that is lower than that of
the data U because the application frequency is low.
[0027] Namely, it can be said that since the systematic bits have a
higher degree of importance than that of the parity bits, and the
systematic bits are received with greater accuracy, the more
accurate decoding result can be obtained with the turbo
decoder.
[0028] The systematic bits and parity bits that are generated as
described above may be inputted as the serial data to the bit
separating unit 4. The bit separating unit 4 separates the input
serial data into the data U, U', and U'' of three systems, and then
outputs this data as parallel data.
[0029] The rate matching unit 5 preferably performs the puncture
process for deleting the bits with the predetermined algorithm and
also executes the repetition process to repeat the bits in order to
store the data within the sub-frame formed of three slots of the
HS-PDSCH channel.
[0030] As described above, the bits having completed the bit
adaptation process to the sub-frame are then inputted in parallel
to the bit collecting unit 6.
[0031] The bit collecting unit 6 preferably generates bit sequences
of four bits indicating each signal point, for example, of 16-level
QAM modulation based on the input data and then outputs these bit
sequences. At the time of generation of bit sequences, the
systematic bits are preferably arranged, for the first
transmission, in the side of upper bits in which an error is not
easily generated.
[0032] The modulating unit 7 outputs the signal of the 16-level QAM
modulation to provide the amplitude and phase corresponding to the
signal points indicated with the input bit sequences and then
provides the signal to the side of the antenna (not illustrated)
after conversion to the radio frequency through the frequency
conversion.
[0033] "Detailed Description of the Rate Matching Unit 5"
[0034] FIG. 3 illustrates one embodiment of the rate matching unit
5. The rate matching unit 5 comprises, as illustrated, a first rate
matching unit 51, a virtual buffer 52, and a second rate matching
unit 53.
[0035] The first rate matching unit 51 executes the rate matching
process (puncture process) to the first parity bits (U') and second
parity bits (U'') separated in the bit separating unit 4. This
process may be executed, considering the capability of the mobile
station in the receiving side described below (capacity of memory
or the like to store the data obtained by combining the received
data and re-transmitted data), in order to keep the maximum amount
of data which can be transmitted including the re-transmission
under the capability of the mobile station. Accordingly, bits are
deleted on the basis of a predetermined rule.
[0036] The virtual buffer unit 52 may be provided to store the
systematic bits. The first and second parity bits may have
completed the puncture process (deletion of bits) in accordance
with the capability of the mobile station.
[0037] The second rate matching unit 53 performs the puncture
process and the repetition process. The puncture process deletes
the bits based on the predetermined rule, and the repetition
process repeats the bits for the data read from the virtual buffer
in order to store the data within the sub-frame formed from the
three slots of the HS-PDSCH channel.
[0038] The structure and operations of the rate matching unit 5 are
described above and one embodiment of data due to the process
performed by the rate matching unit 5 will be described with
reference to FIG. 4.
[0039] The block A in FIG. 4 illustrates the systematic bits (U),
first parity bits (U'), and second parity bits (U'') inputted to
the first rate matching unit 51.
[0040] The first rate matching process unit 51 executes the
puncture process to the block A to attain the predetermined amount
of data determined in accordance with the capability of the mobile
station and then provides an output. Namely, the bits are deleted
to result in the amount of data indicated in the block B
considering the capability of the mobile station.
[0041] Various methods may be assumed for deletion of bits. For
example, the block B illustrated in FIG. 4 may be formed by not
applying the puncture process to the systematic bits. These
systematic bits are important, and the puncture process is applied
to the first and second parity bits (indicated as U'(r) and U''(r)
in order to show execution of the puncture process as the rate
matching process). In FIG. 4, the left half bits are deleted but it
is preferable to delete the bits at the positions which a dispersed
to a certain degree. For example, the even number bits or odd
number bits are deleted.
[0042] The second rate matching unit 53 executes the rate matching
process to store the data within the sub-frame on the basis of the
data block B puncture-processed in the first rate matching unit 51
and then outputs the transmitting data.
[0043] For example, with the first transmission, the systematic
bits U are outputted as the block C after execution of the puncture
process. With the second transmission (first re-transmission), the
first parity bits U'(r) and the second parity bit U''(r) are
outputted as block D after execution of the puncture process. The
number of times that the re-transmission may occur may be a
predetermined number equal to 1 or larger. However, when the third
transmission is assumed to be the last re-transmission which
includes the first transmission, the block C obtained by the
puncture process is transmitted again, for example, to the block B
in the third transmission (second re-transmission).
[0044] The items regarding the HSDPA channel are disclosed, for
example, in the non-patent document "3G TS 25. 212 (3.sup.rd
Generation Partnership Project: Technical Specification Group Radio
Access Network; Multiplexing and channel coding (FDD))".
[0045] According to the background technology described above, the
amount of data transmitted to a mobile station is previously
limited (limited to the block B), with the (first) rate matching,
to the value below the capability of the receiving apparatus
(capacity of memory or the like to store the data obtained by
combining the received data and re-transmitted data). Thus, the
receiving apparatus does not receive data exceeding the capability
(capacity of memory) and is capable of executing the error
correction decoding process by completely utilizing the first
receiving data and the re-transmitted receiving data.
[0046] However, such limitation will close the way of utilization
of the data part exceeding the capacity of memory of the receiving
apparatus. This will result in the disadvantage that the sufficient
capability of the error correction decoding process cannot be
ensured.
[0047] Elimination of such limitation may be achieved by increasing
the capacity of the memory of the receiving apparatus. However,
when reduction in the size of the mobile station is alienated due
to the increase in capacity of memory and particularly when
soft-determination data is used for the error correction decoding
process, the amount of data increases drastically. Therefore,
elimination of the limitation cannot be employed directly.
SUMMARY OF THE INVENTION
[0048] In one embodiment, the present invention is capable of
effectively executing the error correction decoding process while
increasing the amount of data which must be stored in the receiving
apparatus in a controlled manner.
[0049] In one embodiment, the present invention comprises a
transmitting apparatus for transmitting data to a receiving
apparatus which executes error correction decoding processes using
the received data and the re-transmitted data. The apparatus
includes: a transmitting data generating unit for generating a
first set of transmitted data by executing a rate matching process
to a first part of the error correction encoded data and generating
a second set of transmitted data including at least the data not
included to the first part by executing the rate matching process
to the entire part or a second part of the error correction encoded
data. Also included is a transmitting unit for re-transmitting the
second set of transmitted data after transmission of the first set
of transmitted data.
[0050] Preferably, the transmission of the second set of
transmitted data is the last re-transmission among the continuous
re-transmissions to be executed.
[0051] It may be desirable for the second set of transmitted data
to include a data part common to the first set of transmitted data.
Preferably, the transmission of the second set of transmitted data
is not the last re-transmission among the continuous
re-transmissions to be executed.
[0052] In one embodiment, the first data part may be attained by
executing the rate matching process to the error correction encoded
data.
[0053] Preferably, the first part is the data portion obtained by
executing the rate matching process in a first pattern to the error
correction encoded data. The second part is the data portion
obtained by executing the rate matching process in a second pattern
to the error correction encoded data.
[0054] In one embodiment, a transmitting apparatus for transmitting
data to a receiving apparatus which executes the error correction
decoding process by using a combined data of the received data and
the re-transmitted data may also be included.
[0055] The apparatus comprises a transmitting data generating unit
for generating a transmitting data for a particular re-transmission
identified by a receiving apparatus. This occurs when the amount of
data obtained by combining the transmitting data and the data
transmitted already exceeds the capacity of a storing unit provided
in the receiving apparatus for storing a combined received data. A
transmitting unit for transmitting the transmitting data as the
particular re-transmission may also be included.
[0056] Preferably, the transmitting apparatus further comprises a
control unit making a determination on the basis of any of, the
number of times of transmission, the number of times of continuous
reception of the NACK signal, and the passage of time from the
first transmission.
[0057] Preferably, the transmitting apparatus further comprises a
notifying unit capable of notifying the particular re-transmission
to the receiving apparatus.
[0058] Preferably, the transmitting apparatus is a base station
used in the mobile communication system for supporting the HSDPA,
while such notification is executed via the HS-SCCH.
[0059] In one embodiment, the present invention comprises a
transmitting apparatus that includes a transmitting unit for
transmitting data to a receiving apparatus which executes the error
correction decoding process by using data obtained by combining
previously received data and re-transmitted data. Also included is
a notifying unit for notifying the receiving apparatus of the last
re-transmission among a series of re-transmissions to be executed
by said transmitting unit.
[0060] In another embodiment, the present invention comprises a
receiving apparatus for executing the error correction decoding
process by using data obtained by combining a received data and a
re-transmitted data. The receiving unit also includes a storage
unit for storing the first received data, and a controlling unit.
The controlling unit combines the data read from the storage unit
with received data transmitted in the re-transmission and stores
the combined data to the storage unit in the not particular
re-transmission. The controlling unit combines the data read from
the storage unit with the received data transmitted and not stores
the combined data in the particular re-transmission and
controlling.
[0061] In another embodiment, the present invention comprises a
receiving apparatus that executes an error correction decoding
process by using data obtained by combining received data and
re-transmitted data. The apparatus includes a storage unit for
storing the first received data, and a control means to execute the
control for the received data in the re-transmission. The control
means combines the data read from the storage unit with the
received data and stores the combined data in the storage unit in
the not particular re-transmission. However, the received data in
the particular re-transmission, to combine the data read from the
storage means with the received data, to store the data part
corresponding to the data stored by the storage unit among the
combined data to the storage unit but not to store the data part
not corresponding to the data stored by the storage unit to the
storage unit.
[0062] Preferably, the receiving apparatus further comprises a
re-transmission detecting unit for determining a re-transmission
based on any of, the contents notified from a base station, the
number of times of transmission of the NACK signal, the number of
times of reception, and the passage of time from the first
reception.
[0063] Preferably, the receiving apparatus is a mobile station used
in the mobile communication system supporting the HSDPA. Whether
the transmission is the particular re-transmission or not is
determined by a particular re-transmission detecting unit for
determining the particular re-transmission with the information
notified from a base station via the HS-SCCH.
[0064] In one embodiment, the present invention comprises a
receiving apparatus for executing the error correction decoding
process by using data by combining the received data stored in a
storage unit and the re-transmitted data. The apparatus comprises a
determining unit for determining whether the re-transmission is the
last re-transmission or not, and a control unit. The control unit
controls the storage unit to store the combined data of the data
re-transmitted the determining unit determines that the
re-transmission is not the last re-transmission and controls the
storage unit not to store the combined data of the data
re-transmitted by the last re-transmission when the determining
unit determines the re-transmission is the last
re-transmission.
[0065] In another embodiment, the present invention comprises a
re-transmission control method in which if a mobile station having
received the data transmitted from a base station has detected a
receiving error, the mobile station transmits a re-transmission
request to the base station and the base station executes the
re-transmission in accordance with the re-transmission request. The
method includes the base station transmitting, at the time of the
particular re-transmission, the transmitting data wherein an amount
of a data obtained by combining the transmitting data and data
which have already been transmitted exceeds the capacity of the
storage unit of the mobile station for storing the combined data.
While the mobile station executes the error correction decoding
process through the combining between the receiving data of the
particular re-transmission and the received data stored in the
storage unit but does not store the combined data to the storage
unit.
[0066] In another embodiment, the present invention comprises a
data transmission method in a CDMA mobile communication system
introducing the H-ARQ.
[0067] For a first transmission, a first rate matching unit
executes the rate matching process in a first pattern to output a
first set of data, while a second rate matching process unit
executes the rate matching process to the first set of data to
output a second set of data. For the particular re-transmission,
the first rate matching unit executes the rate matching process in
a second pattern to output a third set of data including the data
not included in the first set of data, while the second rate
matching process unit executes the rate matching process to the
third set of data to output a fourth set of data including the data
not included in the first set of data.
BRIEF DESCRIPTION OF THE DRAWINGS
[0068] FIG. 1 is a diagram illustrating one embodiment of a channel
format of the HSDPA channel.
[0069] FIG. 2 is a diagram illustrating one embodiment of a
structure of a base station supporting the HSDPA channel.
[0070] FIG. 3 is a diagram illustrating one embodiment of a rate
matching unit 5.
[0071] FIG. 4 is a diagram illustrating one embodiment of changes
of data in the rate matching unit 5.
[0072] FIG. 5 is a diagram illustrating one embodiment of a
transmitting apparatus according to the present invention.
[0073] FIG. 6 is a diagram illustrating changes of data by the rate
matching process according to one embodiment of the present
invention.
[0074] FIG. 7 is a diagram illustrating one embodiment of a
receiving apparatus according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[a] Description of an Exemplary Embodiment
[0075] FIG. 5 is a diagram illustrating one embodiment of a
transmitting apparatus of the present invention.
[0076] As an example of the transmitting apparatus, one embodiment
of a radio base station in the W-CDMA communication system
corresponding to the HSDPA described previously will be described.
This exemplary transmitting apparatus can also be adapted to the
transmitting apparatus of the other communication systems known to
those skilled in the art.
[0077] In the FIG. 5 embodiment, the reference numeral 10
designates a control unit which sequentially outputs the
transmitting data (data for transmission within one sub-frame) to
be transmitted via the HS-PDSCH channel and controls each unit (11
to 26 or the like). Since the HS-PDSCH channel is the shared
channel, the sequentially outputted transmitting data may be
permitted to be transmitted to different mobile stations.
[0078] The reference numeral 11 designates a CRC attachment unit
for executing the CRC arithmetic operation to the sequentially
inputted transmitting data (data transmitted within the same radio
frame) and adding the result of CRC arithmetic operation to the
last part of the transmitting data. Numeral 12 designates a bit
scrambling unit which forms the random transmitting data by
scrambling, in unit of bit, the transmitting data to which the
result of the CRC arithmetic operation is added.
[0079] Numeral 13 designates an exemplary code block segmentation
unit which segments (into the two blocks) the input transmitting
data having completed bit scrambling if this transmitting data
exceeds the predetermined data length in view of preventing an
increase in the amount of arithmetic operations of the decoder in
the receiving side because the data as the decoding object becomes
too long in the channel encoding to be executed next.
[0080] In FIG. 5, the input data length exceeds the predetermined
data length. In one embodiment, the data segmented to the two
blocks (segmented to the first data block and second data block)
are outputted. The number of segmentations other than 2 may
naturally be selected and moreover the transmitting data can also
be segmented in different data lengths in place of the segmentation
in equal data length.
[0081] Numeral 14 designates an exemplary channel coding unit for
individually executing the error correction encoding to the
segmented data. As the channel coding unit 14, the turbo encoder
described above is preferably used here.
[0082] As described previously, the first output includes, for the
first block, the important systematic bits (U) which is identical
to the data as the encoding object, the first parity bits (U')
obtained by convolutional encoding of the systematic bits (U) and
the second parity bits (U'') obtained by the similar convolutional
encoding of the systematic bits after the interleave process. In a
substantially similar manner, the second output includes, for the
second block, the systematic bits (U), first parity bits (U') and
second parity bits (U'').
[0083] Numeral 15 designates a bit separation unit for separately
outputting the systematic bits (U) of the first block and second
block, the first parity bits (U'), and the second parity bits (U'')
from the channel coding unit 14 (turbo coder). This process may
also be adapted to the second block. Accordingly, only the output
corresponding to the first block is illustrated.
[0084] Numeral 16 designates a first rate matching unit. The
matching unit executes the rate matching process, such as the
puncture process (thinning) to the input data, to provide the input
data (all data of the segmented blocks when the data is segmented
to a plurality of blocks) to be stored in the predetermined region
of the virtual buffer unit 17 of the subsequent stages.
[0085] The first rate matching unit 16 executes the rate matching
in the first pattern when the transmission is either the first
transmission, or not the particular re-transmission. In this case,
the amount of data after the rate matching is preferably set to the
capacity which may be equal to or less than that of the memory.
This may be done to realize the H-ARQ of the mobile station to
receive the data. For example, the control unit 10 of the base
station recognizes the capacity of the memory for H-ARQ of the
mobile station on the basis of the information about the received
capability. It then notifies and sets the recognized capacity to
the first rate matching unit and virtual buffer unit 17.
[0086] Moreover, the first rate matching unit 16 is also
instructed, by the control unit 10, to change the rate matching
pattern (puncture pattern) to the second pattern at the time of the
particular re-transmission.
[0087] As the particular re-transmission time, the last
re-transmission time or the other re-transmission time may be
considered. In any case, the mobile station can preferably
recognize the data, when this data is received, as the data
transmitted by the particular re-transmission.
[0088] Examples of the method with which the base station can
recognize the particular re-transmission are listed below.
Example 1
[0089] The base station may be capable of recognizing the
particular re-transmission when the receiving unit 26 receives the
NACK signal. The NACK signal indicates no-acknowledgment of
reception from the mobile station about the transmitting data
transmitted from the base station and the control unit 10 detects
that the number of times of continuous reception of the NACK signal
has reached the predetermined value M. (M is preferably a natural
number).
Example 2
[0090] The base station may be capable of recognizing the
particular re-transmission when the control unit 10 detects the
necessity of the re-transmission with which the number of times of
transmission including the first transmission reaches the
predetermined value N (N: natural number). This preferably occurs
at the time of execution of the re-transmission control based on
the NACK signal which indicates no-acknowledgment of reception from
the mobile station about the transmitting data transmitted from the
base station.
Example 3
[0091] The base station can recognize the particular
re-transmission when the control unit 10 detects that the
predetermined time T has passed from the first transmission by the
base station and the re-transmission of the data about the error
correction encoding data equal to that in the first transmission is
required.
[0092] In one embodiment, the mobile station may be capable of
recognizing the particular re-transmission and may be capable of
recognizing, in the case of the example 1, the re-transmission in
accordance with the NACK signal. This preferably occurs when the
NACK signal has reached the predetermined value M as the particular
re-transmission by counting the number of times of the continuous
transmissions of the NACK signal. Moreover, in the case of the
example 2, the mobile station can also recognize, for example, the
N-th reception which has reached the predetermined value N (only in
the case regarding the same error correction encoded data) by
counting the number of times of reception N. In addition, in the
example 3, the mobile station can recognize, for example, that the
predetermined time T has passed from the first reception and
reception of the data by the re-transmission regarding the error
correction encoded data which is substantially similar to the data
of the first reception is caused by the particular
re-transmission.
[0093] Here, the predetermined values M, N, and T may be previously
stored in the mobile station and may also be notified from the base
station.
[0094] Moreover, whether the transmitting data to the mobile
station from the base station is the data in the particular
re-transmission or not (whether the re-transmission is the last
re-transmission or not) can also be notified in direct with a
certain method, regardless to the examples 1 and 2. For example the
base station notifies to the mobile station via the HS-SCCH channel
or the like by transmitting, to the mobile station, a notifying
signal which indicates the data transmitted via the HS-PDSCH
channel is the particular re-transmission or not.
[0095] As described above, the mobile station may be capable of
recognizing the particular re-transmission with any method
described above.
[0096] Numeral 17 designates an exemplary virtual buffer unit which
is preferably controlled by the control unit 10 to set a region
corresponding to the receiving process capability of the mobile
station as the transmission object and stores the data completing
the rate matching process by the first rate matching unit 16.
During the particular re-transmission (including the last
re-transmission), a pattern of the rate matching (puncture) changes
and therefore data to be stored also changes. In one embodiment,
therefore, the region which can store the data punctured with the
changed pattern may be set by the control unit 10.
[0097] Numeral 18 designates a second exemplary rate matching unit
for adjusting the data to the data length which may be stored by
the control unit 10 in the designated one sub-frame. The data
length of input data is adjusted to provide the designated data
length by executing, for example, the puncture process (thinning)
and repetition process (repeating).
[0098] In one embodiment of the HS-PDSCH system, the parameters
such as modulation method, spreading factor (SF), number of codes
(number of channels) are variable. Therefore, each number of bits
stored within respective sub-frame is variable even when the
sub-frames have the equal length. The control unit 10 notifies the
number of bits in accordance with the parameters to the second rate
matching unit 18 as the data length which can be stored in one
sub-frame. Moreover, the control unit 10 notifies the changed
pattern to the second rate matching unit 18 when the pattern of
rate matching is changed, for example, for execution of each
re-transmission.
[0099] Numeral 19 designates an exemplary bit collection unit for
arranging the data from the second rate matching unit 19 into a
plurality of bit sequences. Namely, a plurality of bit sequences
for indicating the signal points on the respective phase planes may
be outputted by arranging both first block data and second block
data with the predetermined bit arrangement method. In this
embodiment, each bit sequence is formed with four bits because the
16-level QAM modulation system is employed. Of course, the other
multi-level modulation system (for example, 8-phase PSK or the
like) may also be introduced.
[0100] Numeral 20 designates an exemplary physical channel
segmentation unit which can output the segmented bit sequences to
the systems in the same number as the number of spreading codes
(number of codes) notified from the control unit 10. Namely, this
unit may provide an output by sequentially sharing the input bit
sequences to the systems 1 to N, when the number of codes in the
transmitting parameters is N.
[0101] Numeral 21 designates an exemplary interleaving unit for
outputting the bit sequences of the N systems by executing the
interleaving process to such bit sequences.
[0102] Numeral 22 designates an exemplary constellation
re-arrangement unit for 16 QAM which may execute the re-arrangement
of the bits within the bit sequences for each input bit sequence.
For example, it is also possible that at the time of the first
transmission, each input bit is outputted directly without any
process, and during the re-transmission in the H-ARQ described
above, re-arrangement of bits can also be executed. The
re-arrangement of bits means, for example, the process to replace
the upper bits with the lower bits. Accordingly, it is preferable
to perform the replacement of the bits depending on the equal rule
for a plurality of bit sequences. The bit sequences in the
re-transmission may also be outputted substantially directly
without any process.
[0103] Numeral 23 designates an exemplary physical channel mapping
unit for sharing the bit sequences of the N systems in the
subsequent stage into the corresponding spreading unit of the
spreading process unit 24 in the subsequent stage.
[0104] Numeral 24 designates an exemplary spreading process unit
which is provided with a plurality of spreading units to
respectively output the corresponding I, Q voltages on the basis of
each bit sequence of the N systems and also provide an output by
executing the spreading process using different spreading
codes.
[0105] Numeral 25 designates an exemplary modulating unit for
combining (adding) the signals spread by the spreading process unit
24, executing, on the basis of the combined signals, the amplitude
phase modulation such as 16-level QAM modulation and then
transmitting the signal from the antenna as the radio signal
through frequency conversion.
[0106] Numeral 26 designates an exemplary receiving unit which
receives the signal from the mobile station via the HS-DPCCH and
then gives the ACK and NACK signals and the CQI or the like to the
control unit 10.
[0107] Names and operations of respective units are described
above. From the above description, it may be understood that the
rate matching pattern is changed particularly when the first rate
matching unit 16 executes the particular re-transmission. Further
details of this process will then be described below with reference
to FIG. 6.
[0108] "Change in Data by Rate Matching Process"
[0109] The block A in FIG. 6 indicates the systematic bits (U),
first parity bits (U'), and second parity bits (U'') to be inputted
to the first rate matching unit 16. The first rate matching unit 16
executes, when the transmission is not the particular
re-transmission, the rate matching process (puncture process) in
the first pattern to the data of block A. This may be done to
provide the predetermined amount of data determined corresponding
to the capability (memory 31 for H-RAQ) of the mobile station which
is notified by the control unit 10, and to output the data as the
block B which is the first part. In this embodiment, the amount of
data of the block B may be matched with the capacity of the memory
31 but it is also possible that the amount of data is not matched
with such capacity.
[0110] As the first pattern, various patterns such as the pattern
for leaving the systematic bits with priority or the pattern for
leaving the parity bits with priority may be considered. In block
B, for example, the systematic bits are never subjected to the
puncture process because these bits are important bits and are then
outputted substantially directly. However, regarding the first and
second parity bits, the predetermined bits thereof are deleted with
the puncture process (such bits are indicated as U' (r1) and U''
(r1) in order to indicate execution of the first puncture process).
In the figure, the right half bits are deleted but it is preferable
to delete the bits in the positions which are spread to a certain
degree. For example, the even number bits or odd number bits are
deleted.
[0111] Moreover, the first rate matching processing unit 16
executes, at the time of executing the particular re-transmission,
the rate matching process in the second pattern to the data of
block A and provides the output as the block E (expressed as U'(r2)
and U''(r2) in order to indicate that the puncture process in the
second pattern has been executed). The second pattern is preferably
different from the first pattern and includes at least the data not
included in the first pattern.
[0112] Moreover, the particular re-transmission time is desirably
defined as the last re-transmission time to execute the
re-transmission but may also be considered as any re-transmission
time (not always defined as the last re-transmission) identified
with the mobile station.
[0113] For the assumed last re-transmission time, the mobile
station is capable of executing the error correction decoding. This
may be done by combining the data stored before receiving the last
re-transmission in the memory 31 and the data received by the last
re-transmission, because, when the re-transmission is no longer
executed, it is no longer required to store the data to the memory
31 as the data to be combined as the preparation for further
re-transmission of the combined data.
[0114] Moreover, when the mobile station is assumed to be in any
re-transmission time which can be identified as the particular
re-transmission (not always considered as the last re-transmission
time), the mobile station executes the error correction decoding by
combining the data which has already been received and stored in
the memory 31 and the data received during this re-transmission.
The mobile station also executes the particular process to store a
part of the data after the combining process in the memory 31 when
the part of data includes data regarding the same bits as the data
which is already stored in the memory 31. This process enables to
use the received data transmitted by the particular re-transmission
for a next re-transmission.
[0115] The rate matching process in the first rate matching unit 16
has been described above and it should be noted that the data after
the rate matching process in the second pattern includes the bits
which are included in the error correction coded block A but not in
the data after the rate matching process in the first pattern 1.
Specially in one embodiment, since there is no duplicated part in
the data after the rate matching process in the second pattern and
the data after the rate matching process in the first pattern and
the block E corresponds to a complementary aggregation of the block
B when the block A is assumed as the entire block, the data after
the rate matching process in the second pattern includes,
irrespective of the rate matching pattern in the second rate
matching unit, the bits which are included in the error correction
encoded block A but not in the data after the rate matching process
in the first pattern.
[0116] However, it should be noted that the present invention is
never restricted to the example described above by setting of the
rate matching pattern in the second rate matching unit 18 described
later.
[0117] In one embodiment, block 1 may be obtained by puncturing the
block A in the first pattern and block 2 may be obtained by
punching the block A in the second pattern. Each block may include
at least different data portions, at least a part of which can be
left after the second rate matching unit 18 has executed the rate
matching process of the block 2 and the second rate matching unit
18 can execute the rate matching in the pattern which enables such
leaving of a part of the data part.
[0118] In this embodiment, it may be possible to avoid the
situation in which all data received by the mobile station during
the particular re-transmission time can't be used (combining with
next re-transmitted data is impossible), even when the particular
re-transmission is not the last re-transmission and the next
re-transmission is therefore executed, by including the data
included in the data after the puncturing in the first pattern to
the data after the rate matching process for block 2.
[0119] In one embodiment, the second rate matching unit 18 executes
the rate matching process in the pattern designated by the control
unit 10 to store the data within the sub-frame. The storage is done
on the basis of the data block B as the first part punctured in the
first rate matching unit 16 and the data block E as the second
part. The matching unit 18 then outputs the transmitting data as
the blocks C, D, and F. For example, when the particular
re-transmission is the third transmission (second re-transmission),
the second rate matching process unit 18 outputs, at the time of
the first transmission, block C. This may be done by executing the
rate matching process on the basis of the data included in block B
and also outputs block D, at the time of the next transmission, on
the basis of the data included in block B. At the time of the last
re-transmission as the third re-transmission, the second rate
matching process unit 18 executes the rate matching process on the
basis of the data included in the block E to output the block
F.
[0120] Flow of the rate matching process is described Above. In one
embodiment, the transmitting apparatus (the base station) obtains
block F for the particular re-transmission (for example third
transmission) and transmits block F to the receiving apparatus (the
mobile station). Here the receiving apparatus can identify the
particular re-transmission and if the receiving apparatus combines
block F with the data which the receiving apparatus already
received as the data (block C as the first transmission data and
block D as the second transmission data) regarding the same error
correction encoded data (block A), then the amount of the combined
data (block C+block D+block F) exceeds the capacity of memorizing
unit (for example memory 31).
[0121] An example of the rate matching process in the two stages
executed by the first rate matching unit 16 and the second rate
matching unit 18 has been described above, but the data which is
identical to the data obtained by the rate matching in the two
stages can also be generated with the rate matching of only one
stage. In other words, the rate matching process is executed to the
block A in the pattern which can generate substantially directly
the block C, block D, and block F. In one embodiment, it is block A
may be attained by combining blocks C, D, and F and block A may
exceed the size of block B as the capacity of the memory 31.
[0122] Next, one embodiment of the receiving apparatus of the
present invention will be described.
[0123] "Description of Receiving Apparatus (Mobile Station"
[0124] FIG. 7 is a diagram illustrating one embodiment of the
receiving apparatus of the present invention.
[0125] As an example of the receiving apparatus, a receiving
apparatus (mobile station) of the W-CDMA communication system
corresponding to the HSDPA described previously will be described.
This receiving apparatus can also be adapted to the receiving
apparatus in the other communication systems.
[0126] In FIG. 7, numeral 27 designates a receiving unit which
outputs the receiving signal by executing the orthogonal detection
and despread process, or the like, to the receiving signal. In view
of utilizing the soft-determination information in a channel
decoding unit 36 described later, an output of the receiving unit
27 also includes the soft-determination information.
[0127] Numeral 28 designates one embodiment of a particular
re-transmission detecting unit which determines whether the
transmission is the particular re-transmission or not. This may be
done by receiving a notice indicating the transmission is the
particular re-transmission or not via the HS-SCCH, or the like,
before the reception of the data via the HS-PDSCH and then controls
a SW 30 in accordance with the result of determination.
[0128] In another embodiment, the particular re-transmission
detecting unit 28 counts up the number of times of continuous
transmission of the NACK signal and this unit detects that the
counted value has reached the predetermined value M. In this
embodiment, the particular re-transmission detecting unit 28 counts
up the number of times of reception of data via the HS-PDSCH
channel (number of times of transmission regarding the same error
correction encoded data including the first transmission and
re-transmission) and also detects that the counted value has
reached the predetermined value N, and the method in which the
particular re-transmission detecting unit 28 detects, with a timer,
that the predetermined time T has passed from the reception of the
new data.
[0129] Numeral 29 designates a first exemplary depuncture unit
which inserts the information which means the zero degree of
likeliness to the bit position deleted by the puncture process
corresponding to the process inverted to the process of the second
rate matching unit 18. An adverse effect on the error correction
decoding process in the channel decoding unit 36 can be suppressed
by inserting the information which means a substantially zero
degree of likeliness.
[0130] The rate matching pattern in the second rate matching unit
18 can be changed for each transmission. However, since the control
unit 38 can previously recognize such pattern via the HS-SCCH
channel, the control unit 38 is capable of controlling the first
depuncture unit 29 to execute the depuncture process corresponding
to the pattern notified from the base station for each reception of
data.
[0131] Next, numeral 30 designates a switch (SW) unit. The SW unit
30 selects the side of the third depuncture unit 34 with the
control of the particular re-transmission detecting unit 28 when
the data is related to the particular re-transmission. Moreover,
when the data is not related to the particular re-transmission, the
side of a combining unit 32 is selected.
[0132] Accordingly, the data not related to the particular
re-transmission are all considered as the object of combining
process in the combining unit 32.
[0133] Numeral 32 designates a combining unit and numeral 31
designates a memory. The data related to the first transmission is
outputted directly to the second depuncture unit 33 and is then
stored in the memory 31. Meanwhile, the transmitting data of the
second and subsequent transmissions which are not the particular
re-transmission are combined with the data stored in the memory 31
and is then outputted to the second depuncture unit 33 and the
combined data is then stored in the memory 31. For execution of the
combining process, it is considered, for example, to obtain the
average of the likeliness degree information. In one embodiment,
when the likeliness degree is high only in the first reception but
such likeliness degree is low in the subsequent receptions, the
likeliness degree is lowered for that of the first transmission
through the combining process.
[0134] Numeral 33 designates a second depuncture unit and numeral
34 designates a third depuncture unit. The information of zero
degree of likeliness is inserted to the bit position deleted by the
puncture process corresponding to the process inverted from the
process of the first rate matching unit 16.
[0135] When the transmission is not the particular re-transmission,
since the rate matching process is executed in the first pattern,
the second depuncture unit 33 executes the depuncture process
corresponding to the first pattern. When transmission is the
particular re-transmission, since the rate matching process is
executed in the second pattern, the third depuncture unit 34
executes the depuncture process corresponding to the second
pattern.
[0136] It should also be noted that the memory 31 to store the
combined data as the object of depuncture is provided in the
preceding stage of the second depuncture unit 33, while such memory
is not provided at the preceding stage of the third depuncture unit
34.
[0137] Numeral 35 designates an embodiment of a combining unit for
combining the outputs of the second and third depuncture units 33,
34 and then provides the outputs thereof.
[0138] Numeral 36 designates an embodiment of a channel decoding
unit for outputting the error-corrected data by executing the error
correction decoding process such as the turbo decoding process on
the basis of the output from the combining unit 35.
[0139] Numeral 37 designates an embodiment of a CRC check unit for
executing the error detecting process using the CRC bits attached
to the error-corrected data and then notifying the result to the
control unit 38.
[0140] In one embodiment, the control unit 38 controls each unit
and transmits the ACK and NACK signals by controlling the
transmitting unit 39 in accordance with existence of CRC error from
the CRC check unit 37. When the CRC error is not detected, the ACK
signal may be transmitted and when the CRC error is generated, the
NACK signal may be transmitted. Accordingly, the base station
executes the re-transmission when the NACK signal is received.
[0141] In one embodiment, the memory for storing the input/output
data of the third depuncture unit 35 is not provided. However, when
the bit portion duplicated in the first and second patterns exists
in the first rate matching unit 16, the duplicated portion should
preferably be combined with the output of the memory 31 and then
preferably be written to the memory 31. However, since it is
required to provide a measure for the bits to be combined, the
corresponding relationship should preferably be stored preferably
on the basis of the first and second patterns for combining process
among the corresponding bits.
[0142] Accordingly, even if a receiving error is detected when the
particular data is transmitted through the particular
re-transmission and moreover the next re-transmission is executed,
any disadvantage that the data transmitted by the particular
re-transmission cannot be re-used completely is not generated,
ensuring the effective operation.
[0143] As the next re-transmission, it is considered that the first
rate matching unit 16 uses the first pattern or the second pattern.
However, when the first pattern is used, the mobile station
executes the operation for the case where the particular
re-transmission detecting unit 28 does not detect the particular
re-transmission. Meanwhile, when the second pattern is used (it may
be replaced with the third pattern including the bits not included
in the first pattern, unlike the first and the second patterns),
the mobile station executes the operation for the case where the
particular re-transmission detecting unit 28 detects the particular
re-transmission.
[0144] As described above, the data generated from block E, which
includes the data inherently removed from the object of
transmission, in the first rate matching process, caused by the
capability of the mobile station (memory 31 for H-ARQ) may be
transmitted to the mobile station.
[0145] In one embodiment, the receiving apparatus is not required
to store the block E to the memory 31. As described previously,
when the common part exists in the first part generated by the
first puncture pattern and the second part generated by the second
puncture pattern in regard to the same error correction encoded
data, the first rate matching unit 16 can store the common part to
the memory 31. Accordingly, if the particular transmission has
failed, the available part preferably exists in the receiving
data.
[0146] Moreover, when the particular re-transmission detecting unit
28 has detected that the transmission of data from the base station
is the last re-transmission, the mobile station is eased in the
load of control, namely it is no longer required to control the
storage of the combined data to the memory 31, by executing the
operations during the particular re-transmission described
previously.
[b] Description of Another Exemplary Embodiment
[0147] Here, consideration may be taken into account for the case
where the mobile station which can't use the received data
exceeding the capacity of the memory 31 through the error
correction decoding process.
[0148] In one embodiment, the mobile station additionally transmits
the information indicating whether the information corresponds or
not to the particular transmission of the base station described in
the first embodiment at the time of transmitting the capability of
the mobile station itself (capacity information or the like of the
memory 31) when a call is originated. With this transmission, the
control unit 10 of the base station executes the control for
allowing the particular re-transmission, upon determination that
the mobile station can provide the measure for the particular
re-transmission and also executes the control for inhibiting the
particular re-transmission if the mobile station cannot provide the
measure for the particular re-transmission.
[c] Description of a Third Exemplary Embodiment
[0149] For the re-transmission from the base station, the data
being stored in the control unit 10 is outputted again and can also
be re-transmitted with the procedures described in the first
embodiment. However, more preferably, the first rate matching unit
16 can preferably output the data punctured in the first pattern
and the data punctured in the second pattern to the error
correction coded data inputted at the time of the first
transmission and also preferably store such data to the virtual
buffer. In this embodiment, each region of the virtual buffer can
be obtained as required.
[0150] Accordingly, when the particular transmission is not
executed, the data corresponding to the first pattern may be read
from the virtual buffer. Meanwhile, when the particular
transmission is executed, the data corresponding to the second
pattern is read from the virtual buffer and then such data may be
outputted to the second rate matching unit 18 or the like in the
subsequent stage. Therefore, the process in each unit 11 to 15 can
be eliminated.
[0151] When it is no longer desirable to store the data for the
re-transmission as described above, it should also be noted that
the virtual buffer unit is not actually required to be formed with
the buffer apparatus. Namely, the virtual buffer unit of the first
embodiment may be eliminated and the first rate matching unit 16
and the second rate matching unit 18 can be connected with each
other.
[0152] According to one embodiment of the present invention, the
error correction decoding process may be executed effectively while
increasing the control over the amount of data that may be stored
with the receiving apparatus.
[0153] Although the present invention has been described with
reference to particular embodiments, it will be understood to those
skilled in the art that the invention is capable of a variety of
alternative embodiments within the spirit of the appended
claims.
* * * * *