Note: Descriptions are shown in the official language in which they were submitted.
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APPARATUS AND METHOD FOR ALLOCATING OVSF CODES AND I/O
CHANNELS FOR REDUCING PEAK-TO-AVERAGE POWER RATIO IN
TRANSMITTING DATA VIA ENHANCED UP-LINK DEDICATED CHANNELS
IN WCDMA SYSTEMS
This is a divisional application of Canadian Patent Application Serial No.
2,552,234 filed on February 14, 2005.
FIELD OF THE INVENTION
The present invention relates generally to an asynchronous Wideband Code
Division Multiple Access (WCDMA) communication system, and in particular, to
an
apparatus and method for minimizing an increase in Peak-to-Average Power Ratio
(PAPR) of a transmission signal during data transmission through an Enhanced
Uplink
Dedicated transport Channel (EUDCH).
That is, the present invention proposes an optimal Orthogonal Variable
Spreading
Factor (OVSF) code and in-phase/quadrature-phase (I/Q) channel allocation
apparatus
and method for uplink physical channels for EUDCH service.
It should be understood that the expression "the invention" and the like
encompasses the subject-matter of both the parent and the divisional
applications.
BACKGROUND OF THE INVENTION
Currently, an uplink of a WCDMA system includes a Dedicated Physical Data
Channel (DPDCH) and a Dedicated Physical Control Channel (DPCCH) as typical
dedicated physical channels used to transmit user signals. The DPDCH is a data
transport channel over which user data such as voice and image is transmitted,
and the
DPCCH is a control information transport channel on which DPDCH frame format
information and pilot information for DPDCH demodulation and port control are
carried.
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Recently, technology using a EUDCH which is an enhanced uplink data-only
transport channel has been proposed to improve a rate and efficiency of packet
data
transmission in an uplink.
FIG. 1 is a diagram illustrating information exchanged between user equipments
and a Node B to perform uplink transmission.
Referring to FIG. 1, UEs 110, 112, 114 and 116 transmit packet data with
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different transmission power according to their distances from a Node B 100.
The
UE 110 which is located in the longest distance from the Node B 100 transmits
packet data with the highest transmission power 120 for the uplink channel,
while
the UE 114 which is located in the shortest distance from the Node B transmits
the packet data with the lowest transmission power 124 for the uplink channel.
In
order to improve performance of the mobile communication system, the Node B
100 can perform scheduling in such a manner that a level of the transmission
power for the uplink channel should be in reverse proportion to the data rate.
That
is, the Node B allocates the lowest data rate to a HE having the highest
transmission power for the uplink channel, and allocates the highest data rate
to a
UE having the lowest transmission power for the uplink channel.
FIG. 2 is a diagram illustrating information exchanged between a UE and
a Node B to perform uplink transmission. That is, FIG 2 illustrates a basic
procedure required between a Node B 200 and a UE 202 for packet data
transmission through a EUDCH.
Referring to FIG. 2, in step 210, a EUDCH is set up between the Node B
200 and the UE 202. Step 210 includes a process of transmitting/receiving
messages through a dedicated transport channel. After step 210, the UE 202
transmits in step 212 information on a desired data rate and information
indicating an uplink channel condition to the Node B 200. The information
indicating an uplink channel condition includes transmission power of an
uplink
channel transmitted by the UE 202 and a transmission power margin of the UE
203.
The Node B 200 receiving the uplink channel transmission power can
estimate a downlink channel condition by comparing the uplink channel
transmission power with reception power. That is, the Node B 200 considers
that
an uplink channel condition is good if a difference between the uplink channel
transmission power and the uplink channel reception power is small, and
considers that the uplink channel condition is bad if the difference between
the
transmission power and the reception power is great. When the UE transmits
transmission power margin to estimate an uplink channel condition, the Node B
200 can estimate the uplink transmission power by subtracting the transmission
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power margin from the known possible maximum transmission power for the UE.
The Node B 200 determines the possible maximum data rate for an uplink packet
channel of the UE 202 using the estimated channel condition of the UE 202 and
information on a data rate required by the UE 202.
The determined possible maximum data rate is notified to the UE 202 in
step 214. The UE 202 determines a data rate for transmission packet data
within a
range of the notified possible maximum data rate, and transmits in step 216
the
packet data to the Node B 200 at the determined data rate.
Herein, uplink physical channels supporting the EUDCH service include
a Dedicated Physical Data Channel (DPDCH), a Dedicated Physical Control
Channel (DPCCH), a High Speed Dedicated Physical Control Channel (HS-
DPCCH) for HSDPA service, an Enhanced Dedicated Physical Data Channel (E-
DPDCH) for the EUDCH service, and an Enhanced Dedicated Physical Control
Channel (E-DPCCH) for the EUDCH service.
That is, in step 216, the UE 202 transmits an E-DPCCH which is a
control channel to provide frame format and channel coding information of the
E-
DPDCH channel, and transmits packet data through the E-DPDCH. Herein, the
E-DPCCH can also be used for transmission of an uplink data rate required by
the
UE 202 and transmission power margin, and transmission of pilot information
required by the Node B 200 for demodulation of the E-DPDCH.
If the UE 202 additionally transmits separate physical channels in
addition to the existing physical channels in order to transmit EUDCH packet
data as described above, the number of physical channels transmitted in the
uplink increases, causing an increase in a peak-to-average power ratio (PAPR)
of
an uplink transmission signal. It is general that the PAPR increases higher as
the
number of simultaneously transmitted physical channels increases higher.
Because the increase in the PAPR may increase distortion of transmission
signals and an allowed Adjacent Channel Leakage power Ratio (ACLR), a radio
frequency (RF) power amplifier in a UE requires power back-off which reduces
amplifier's input power to prevent the foregoing problem. If the UE performs
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power back-off, the power back-off results in a reduction in reception power
at a
receiver in a Node B, causing an increase in error rate of received data or a
reduction in cell coverage.
Accordingly, in order to prevent the increase in PAPR, the UE intends to
transmit the EUDCH over the existing physical channel such as a DPDCH on a
time division basis, instead of transmitting the EUDCH on a separate physical
channel. However, the process of transmitting the EUDCH over the existing
physical channel on a time division basis causes an increase in implementation
complexity.
Taking the problem into consideration, a WCDMA system has proposed a
method for multiplying the physical channels by OVSF codes satisfying mutual
orthogonality before transmission in the uplink. The physical channels
multiplied
by the OVSF codes can be distinguished in a Node B.
FIG. 3 is a diagram illustrating a tree structure for OVSF codes generally
used in a WCDMA system.
Referring to FIG 3, the OVSF codes can be simply generated in a
calculation process of Equation (1) to Equation (3).
Equation (1)
Cch,I,0 =1.
Equation (2)
[I c20] [ .0 ch,1,0 1_11
I
Cch,2,1 ChM Cch,1.0 1 -1
Equation (3)
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Crh,i(-0,0
ch.r ,0
ch.2",0
Cch,2("0,2 C. I
C21 C
=
= = =
2(')1 (')2
cCh .24 ,2^-1 C032,
C = C ¨
ch.20.4),2(h+1)-1 eh .2"-I
As illustrated in FIG. 3, the OVSF codes are characterized in that
orthogonality is secured between codes having the same spreading factor (SF).
In
addition, for two codes having different SF values, if a code having a larger
SF
value cannot be generated from a code having a lower SF value using Equation
(3), orthogonality is acquired between the two codes.
A description thereof will be made below by way of example.
For SF=4, C
is orthogonal with C6,2,1=(l,-1) but is not
orthogonal with Cch,2,0=(1,1).
As another example, comparing SF=256 OVSF codes with the
Cch,20----(1,1), because OVSF codes with SF=0-127 are generated from the
Cch,2,1=(l51), orthogonality is not secured therebetvveen. That is, as a
higher data
rate is required, an OVSF code with a lower SF value is used, and when a
plurality of physical channels are simultaneously transmitted, the OVSF codes
should be allocated such that orthogonality should necessarily be secured
therebetween.
Even though two physical channels use the same OVSF code, if they are
separately transmitted through an I channel and a Q channel of a transmitter,
a
receiver can separate the two physical channel signals without mutual
interference and demodulate the separated physical channel signals, because
the
signals transmitted on the I channel and the Q channel are carried by carriers
having a 90 -phase difference.
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As described above, an increase in uplink PAPR depends on the number
of physical channels simultaneously transmitted in the uplink, a power ratio
between physical channels, an OVSF code used for each physical channel, and
I/Q channel allocation for each physical channel.
In the WCDMA system to which the EUDCH technology is applied, if E-
DPCCH and E-DPDCH channels for transmission of EUDCH packet data are
simultaneously transmitted in addition to the uplink channels, the PAPR
increases
undesirably.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a UE's
transmission apparatus and method for efficiently transmitting packet data
through an enhanced uplink in a mobile communication system.
It is another object of the present invention to provide an OVSF code and
I/Q channel allocation apparatus and method for minimizing an increase in PAPR
of an uplink transmission signal in a mobile communication system supporting
an
uplink.
It is further another object of the present invention to provide an
apparatus and method for allocating I/Q channels and OVSF codes for E-
DPDCHs and an E-DPCCH to minimize an increase in PAPR according to
presence/absence of an HS-DPCCH and the number of codes for DPDCHs.
In accordance with one aspect of the present invention, to achieve the
objects of the present invention, there is provided a method for transmitting
packet data in a mobile communication system supporting transmission of
enhanced uplink packet data, the method including the steps of: generating a
dedicated physical control channel (DPCCH) using an Orthogonal Variable
Spreading Factor (OVSF) code (256, 0) and a quadrature-phase (Q) channel;
generating a dedicated physical data channel (DPDCH) using an OVSF code
(SFDpDcH, SFDpncti/4) and an in-phase (I) channel, where SFDpDcH denotes a
spreading factor of the DPDCH; generating an E-DPCCH using an OVSF code
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(SFE-DPcoi, 1) and the I channel, where SFE-DPCCH denotes a spreading factor
of an
OVSF code to be allocated to an E-DPCCH for supporting transmission of
enhanced uplink packet data; generating an E-DPDCH using an OVSF code
(SFE-Dpncii, SFE-DPDCH/2) and the Q channel, where SFE-DPDCH denotes a
spreading
factor (SF) value of an OVSF code to be allocated to an E-DPDCH and the SFE_
DPDCH is larger than 4; forming one complex symbol stream by summing up the
generated I and Q channels and scrambling the complex symbol stream; and
transmitting the scrambled complex symbol stream through an antenna.
In accordance with another aspect of the present invention, to achieve the
objects of the present invention, there is provided a method for transmitting
uplink
packet data in a mobile communication system supporting transmission of
enhanced uplink packet data, the method including the steps of: generating
dedicated physical channels and a dedicated physical control channel for
supporting a high speed downlink packet service using Orthogonal Variable
Spreading Factor (OVSF) codes; generating dedicated physical channels for
transmission of enhanced uplink packet data using OVSF codes unused by the
physical channels; forming one complex symbol stream by summing up an I
channel and a Q channel of the generated channels and scrambling the complex
symbol stream; and transmitting the scrambled complex symbol stream through an
antenna.
According to an aspect of the present invention, there is provided a method
for transmitting enhanced packet data in a mobile communication system, the
method comprising the steps of:
generating a dedicated physical control channel (DPCCH) using an
Orthogonal Variable Spreading Factor (OVSF) code (256, 0) and a quadrature-
phase (Q) channel;
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generating a dedicated physical data channel (DPDCH) using an OVSF
code (SFDPDCH, SFDPDCH/4) and an in-phase (I) channel, where SFDPDCH denotes a
spreading factor-of the DPDCH;
generating an E-DPCCH using an OVSF code (SFE-DPccn, 1) and the I
channel, where SFE-DPCCH denotes a spreading factor of an OVSF code to be
allocated to an enhanced dedicated physical control channel (E-DPCCH) for
supporting transmission of enhanced uplink packet data; and
generating an E-DPDCH using an OVSF code (SFE_DpDcH, SFE-DpDcH/2) and
the Q channel, where SFE-DPDCH denotes a spreading factor of an OVSF code to
be
allocated to an enhanced dedicated physical data channel (E-DPDCH) for
supporting transmission of the enhanced uplink packet data.
According to another aspect of the present invention, there is provided an
apparatus for transmitting enhanced packet data in a mobile communication
system, the apparatus comprising:
a controller for allocating an orthogonal variable spreading factor (OVSF)
code (256, 0) and a quadrature-phase (Q) channel to a dedicated physical
control
channel (DPCCH), allocating an OVSF code (SFDPDCH, SFDPDCH/4) and an in-
phase (I) channel to a dedicated physical data channel (DPDCH), where SFDPDCH
denotes a spreading factor of the DPDCH, allocating an enhanced dedicated
physical control channel (E-DPCCH) to an OVSF code (SFE-DPCCH) 1) and the I
channel, where SFE_DpccH denotes a spreading factor of an OVSF code to be
allocated to the E-DPCCH for supporting transmission of enhanced uplink packet
data, and allocating an enhanced dedicated physical data channel (E-DPDCH) to
an OVSF code (SFE-DPDcH, SFE_DpDcH/2) and the Q channel, where SFE-DPDCH
denotes a spreading factor of an OVSF code to be allocated to the E-DPDCH for
supporting transmission of the enhanced uplink packet data;
a spreader for spreading the E-DPDCH and the E-DPCCH according to a
control signal from the controller;
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a summer for summing up the spread E-DPDCH and E-DPCCH; and
a transmitter for transmitting the summed signal.
According to a further aspect of the present invention, there is provided a
method for receiving enhanced packet data in a mobile communication system,
the
method comprising the steps of:
receiving information indicating a transport channel condition from a user
equipment (UE);
transmitting scheduling allocation information indicating data rate
information of an enhanced dedicated physical data channel (E-DPDCH) to the
UE;
receiving a dedicated physical control channel (DPCCH) using an
orthogonal variable spreading factor (OVSF) code (256, 0) and a quadrature-
phase
(Q) channel;
receiving a dedicated physical data channel (DPDCH) using an OVSF code
(SFDpDcH, SFDrDcH/4) and an in-phase (I) channel, where SFDPDCH denotes a
spreading factor of the DPDCH;
receiving an enhanced dedicated physical control channel (E-DPCCH)
using an OVSF code (SFE-DPCCH, 1) and the I channel, where SFE-DPCCH denotes a
spreading factor of an OVSF code to be allocated to the E-DPDCH for supporting
transmission of enhanced uplink packet data; and
receiving an E-DPDCH using an OVSF code (SFE-Drocii, SFE-Dpncii/2) and
the Q channel, where SFE-DPDCH denotes a spreading factor of an OVSF code to
be
allocated to the E-DPDCH for supporting transmission of the enhanced uplink
packet data.
According to a further aspect of the present invention, there is provided an
apparatus for receiving enhanced packet data in a mobile communication system,
the apparatus comprising:
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a receiver for receiving information indicating a transport channel
condition from a user equipment (UE), receiving a dedicated physical control
channel (DPCCH) using an orthogonal variable spreading factor (OVSF) code
(256, 0) and a quadrature-phase (Q) channel, receiving a dedicated physical
data
channel (DPDCH) using an OVSF code (SFDpDcH, SFDpDcH/4) and an in-phase (I)
channel, where SFDPDCH denotes a spreading factor of the DPDCH, receiving an
enhanced dedicated physical control channel (E-DPCCH) using an OVSF code
(SFE_Dpccx, 1) and the I channel, where SFE-DPCCH denotes a spreading factor
of an
OVSF code to be allocated to the E-DPCCH for supporting transmission of
enhanced uplink packet data, and receiving an enhanced dedicated physical data
channel (E-DPDCH) using an OVSF code (SFE-DPDCH, SFE-mocH/2) and the Q
channel, where SFE_DpDcH denotes a spreading factor of an OVSF code to be
allocated to the E-DPDCH for supporting transmission of the enhanced uplink
packet data;
a transmitter for transmitting scheduling allocation information indicating
data rate information of the E-DPDCH to the UE; and
a controller for controlling the receiver and the transmitter.
According to a further aspect of the present invention, there is provided a
method for supporting an enhanced packet service in a mobile communication
system, the method comprising the steps of:
allocating a data channel for transmitting enhanced packet data to a
quadrature-phase (Q) channel considering the maximum number of transmittable
uplink physical channels; and
additionally allocating a data channel for transmitting enhanced packet data
to an in-phase (I) channel to guarantee a data rate of the enhanced packet
data.
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In some embodiments, when a high speed packet service is supported, a
data channel for transmitting enhanced packet data is allocated to the I
channel
considering the maximum number of transmittable uplink physical channels.
In some embodiments, when a high speed packet service is supported, a
data channel for transmitting enhanced packet data is additionally allocated
to the
Q channel to guarantee a data rate of the enhanced packet data.
In some embodiments, the data channel for transmitting the enhanced
packet data is allocated an Orthogonal Variable Spreading Factor (OVSF) code
(SF, SF/2).
In some embodiments, 2, 4, 8, 16, 32, 64, 128 and 256 are available for a
spreading factor of the data channel.
In some embodiments, an enhanced control channel for transmitting control
information related to the data channel for transmitting the enhanced packet
data is
allocated an OVSF code (SF, 1) on the I channel.
In some embodiments, 8, 16, 32, 64, 128 and 256 are available for a
spreading factor of the enhanced control channel.
According to a further aspect of the present invention, there is provided a
method for transmitting packet data in a mobile communication system, the
method comprising the steps of:
generating a dedicated physical control channel (DPCCH) using an
Orthogonal Variable Spreading Factor (OVSF) code (256, 0) and a quadrature-
phase (Q) channel;
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generating a dedicated physical data channel (DPDCH) using an OVSF
code (SFDpDcH, SFDpDcH/4) and an in-phase (I) channel, where SFDEDcH denotes a
spreading factor of the DPDCH;
generating an E-DPCCH using an OVSF code (SFE_Dpcm, 1) and the 1
channel, where SFE-DPCCH denotes a spreading factor of an OVSF code to be
allocated to a dedicated control channel (E-DPCCH) for supporting transmission
of enhanced uplink packet data; and
generating an E-DPDCH using an OVSF code (SFE-DPDCH, SFE-DPDCH/2) and
the Q channel, where SFE-DPDCH denotes a spreading factor of an OVSF code to
be
allocated to a dedicated data channel (E-DPDCH) for supporting transmission of
the enhanced uplink packet data.
In some embodiments, the method further comprises the step of, if SFE_
DPDCH is 4 and two E-DPDCHs are simultaneously transmitted, simultaneously
generating an E-DPDCH1 and an E-DPDCH2 which are spread with an OVSF
code (4, 2) on the I channel and the Q channel, respectively.
In some embodiments, the method further comprises the step of, if SFE_
DPDCH is 2 and two E-DPDCHs are simultaneously transmitted, generating an E-
DPDCH1 and an E-DPDCH2 which are spread with an OVSF code (2, 1) on the I
channel and the Q channel, respectively.
In some embodiments, the method further comprises the step of, if SFE_
DPDCH is 2 and one E-DPDCH is transmitted, generating an E-DPDCH which is
spread with an OVSF code (2, 1) on the Q channel.
In some embodiments, the method further comprises the step of, if an E-
DPCCH is transmitted, generating an E-DPCCH which is spread with an OVSF
code (256, 1) on the I channel.
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In some embodiments, the method further comprises the step of, if a high
speed downlink packet access (HSDPA) service is achieved, generating a high
speed downlink physical channel (HS-DPCCH) using an OVSF code (256, 64)
and the Q channel.
In some embodiments, the method further comprises the step of, if no
DPDCH is transmitted, generating third and fourth E-DPCCHs using an OVSF
code (4, 1).
In some embodiments, the method further comprises the step of using an
OVSF code (4, 1) and the I channel for the third E-DPCCH and using an OVSF
code (4, 1) and the Q channel for the fourth E-DPCCH.
According to a further aspect of the present invention, there is provided an
apparatus for transmitting uplink packet data in a mobile communication system
supporting transmission of enhanced uplink packet data, the apparatus
comprising:
a transmission controller for determining the number of enhanced uplink
data channels considering the maximum number of transmittable dedicated
physical channels, and alternately allocating an Orthogonal Variable Spreading
Factor (OVSF) code (SF, SF/2) to at least one enhanced uplink data channels on
a
quadrature-phase (Q) channel and an in-phase (I) channel according to a data
rate
of the enhanced packet data; and
a transmitter for alternately generating enhanced data channels on the Q
channel and the I channel according to the number of enhanced uplink data
channels, determined by the transmission controller, spreading the packet data
according to the OVSF code, and transmitting the spread packet data.
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In some embodiments, the transmission controller allocates an I channel
and an OVSF code (SF, 1) to an enhanced uplink control channel for
transmitting
control information related to the enhanced uplink data channel.
In some embodiments, 2, 4, 8, 16, 32, 64, 128 and 256 are available for a
spreading factor of the enhanced uplink data channel.
In some embodiments, 8, 16, 32, 64, 128 and 256 are available for a
spreading factor for the enhanced uplink control channel.
According to a further aspect of the present invention, there is provided a
method for transmitting data in a mobile communication system supporting
transmission of uplink packet data, the method comprising the steps of:
allocating an orthogonal code considering a data rate for transmission of
the uplink packet data, and spreading the packet data using the orthogonal
code;
summing up the spread packet data signal and a signal spread with another OVSF
code; and
transmitting the summed spread signal through an antenna;
wherein if a dedicated physical channel (DPDCH) and a dedicated physical
channel (HS-DPCCH) for a high speed downlink packet are not set up, an
orthogonal code (SFE-DPDCH) SFE-DPDCH/4) for an in-phase (I) channel is
allocated
for transmission of the uplink packet data, where SFE-DPDCH denotes a
spreading
factor.
In some embodiments, the SFE_DpDcH is one of 4, 8, 16, 32, 64, 128, 256 and
512.
In some embodiments, when the SFE-DPDCH is 4 and the data rate cannot be
satisfied, an orthogonal code (2, 1) for the I channel is allocated.
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In some embodiments, when two orthogonal codes are allocated for
transmission of the packet data, an orthogonal code (2, 1) for the I channel
and an
orthogonal code (2, 1) for the Q channel are allocated.
In some embodiments, when four orthogonal codes are allocated for
transmission of the packet data, orthogonal code (2, 1) for the I and Q
channels
and orthogonal code (4, 1) for the I and Q channels are allocated.
According to a further aspect of the present invention, there is provided a
method for transmitting data in a mobile communication system supporting
transmission of uplink packet data, the method comprising the steps of:
allocating an orthogonal code considering a data rate for transmission of
the uplink packet data, and spreading the packet data using the orthogonal
code;
summing up the spread packet data signal and a signal spread with another
orthogonal code; and
transmitting the summed spread signal through an antenna;
wherein if no dedicated physical channel (HS-DPCCH) for a high speed
downlink packet is set up, an orthogonal code (SFE-DPDcH, SFE_DpDcH/4) for a
quadrature-phase (Q) channel is allocated for transmission of the uplink
packet
data, where SFE-DPDCH denotes a spreading factor.
In some embodiments, the SFE_DpDcH is one of 4, 8, 16, 32, 64, 128, 256 and
512.
In some embodiments, if the SFE_DpDcH=4 and the data rate cannot be
satisfied, an orthogonal code (2, 1) for the Q channel is allocated.
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In some embodiments, when two orthogonal codes are allocated for the
packet data, an orthogonal code (2, 1) for the Q channel and an orthogonal
code
(2, 1) for the I channel are allocated.
In some embodiments, when four orthogonal codes are allocated for the
packet data, an orthogonal code (2, 1) for the Q and I channels and an
orthogonal
code (4, 1) for the Q and I channels are allocated.
According to a further aspect of the present invention, there is provided a
method for transmitting data in a mobile communication system supporting
transmission of uplink packet data, the method comprising the steps of:
allocating an orthogonal code considering a data rate for transmission of
the uplink packet data, and spreading the packet data using the orthogonal
code;
summing up the spread packet data signal and a signal spread with another
orthogonal code; and
transmitting the summed spread signal through an antenna;
wherein when a dedicated physical channel (HS-DPCCH) for a high speed
downlink packet is set up, one of orthogonal codes (SFE_DpcH, 1) to (SFE-
Dpccx,
SFE-Dpcaii8) for a quadrature-phase (Q) channel is selected and allocated to a
control channel for transmission of the uplink packet data, where SFE_DpDcH
denotes a spreading factor.
In some embodiments, the SFE-DPCCH is one of 8, 16, 32, 64, 128, 256 and
512.
According to a further aspect of the present invention, there is provided a
method for transmitting data in a mobile communication system supporting
transmission of uplink packet data, the method comprising the steps of:
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allocating an orthogonal code considering a data rate for transmission of
the uplink packet data, and spreading the packet data using the orthogonal
code;
summing up the spread packet data and a signal spread with another
orthogonal code; and
transmitting the summed spread signal through an antenna;
wherein if there is no dedicated physical channel (DPDCH), one of
orthogonal codes (SFE-DPccii, _o t (S , _FE-DPCCH) SFE-DPCCH/8) for a
quadrature-phase
(Q) channel is selected regardless of a dedicated physical channel (HS-DPCCH)
for a high speed downlink packet and allocated to a control channel for
transmission of the uplink packet data, where SFE_DpDcH denotes a spreading
factor.
According to a further aspect of the present invention, there is provided a
method for transmitting packet data in a mobile communication system, the
method comprising the steps of:
generating a dedicated physical control channel (DPCCH) using an
Orthogonal Variable Spreading Factor (OVSF) code (256, 0) and a quadrature-
phase (Q) channel;
generating a dedicated physical data channel (DPDCH) using an OVSF
code (SFDPDcH, SFDPDcH/4) and an in-phase (I) channel, where SFDPDCH denotes a
spreading factor of the DPDCH;
generating an E-DPCCH using an OVSF code (SFE_DpccH, 1) and the I
channel, where SFE_DpccH denotes a spreading factor of an OVSF code to be
allocated to a dedicated control channel (E-DPCCH) for supporting transmission
of enhanced uplink packet data; and
allocating an OVSF code (SFE-DPDCH, SFE-DPDCH/2) for an E-DPDCH, where
SFE-DPDCH denotes a spreading factor of an OVSF code to be allocated to a
dedicated data channel (E-DPDCH) for supporting transmission of the enhanced
uplink packet data;
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wherein if a high speed downlink physical channel (HS-DPCCH) is set up,
an E-DPCCH is generated using the I channel, and if the HS-DPCCH is not set
up,
an E-DPCCH is generated using the Q channel.
In some embodiments, the method further comprises the step of, if SFE_
DPDCH is 4 and two E-DPDCHs are simultaneously transmitted, simultaneously
generating an E-DPDCH 1 and an E-DPDCH2 which are spread with an OVSF
code (4, 2) on the I channel and the Q channel, respectively.
In some embodiments, the method further comprises the step of, if SFE_
DPDCH is 2 and two E-DPDCHs are simultaneously transmitted, generating an E-
DPDCH1 and an E-DPDCH2 which are spread with an OVSF code (2, 1) on the I
channel and the Q channel, respectively.
In some embodiments, the method further comprises the step of, if SFE_
DPDCH is 2 and one E-DPDCH is transmitted, generating an E-DPDCH which is
spread with an OVSF code (2, 1) on the Q channel.
In some embodiments, the method further comprises the step of, if an E-
DPCCH is transmitted, generating an E-DPCCH which is spread with an OVSF
code (256, 1) on the I channel.
In some embodiments, the method further comprises the step of, if a high
speed downlink packet access (HSDPA) service is achieved, generating a high
speed downlink physical channel (HS-DPCCH) using an OVSF code (256, 64)
and the Q channel.
In some embodiments, the method further comprises the step of, if no
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DPDCH is transmitted, generating third and fourth E-DPCCHs using an
OVSF code (4, 1).
In some embodiments, the method further comprises the step of generating
the third E-DPCCH using an OVSF code (4, 1) and the I channel and generating
the fourth E-DPCCH using an OVSF code (4, 1) and the Q channel.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present
invention will become more apparent from the following detailed description
when taken in conjunction with the accompanying drawings in which:
FIG. 1 is a diagram illustrating user equipments (UEs) performing uplink
transmission and a Node B;
FIG. 2 is a diagram illustrating information exchanged between a UE and a
Node B to perform uplink transmission;
FIG. 3 is a diagram illustrating a tree structure for general OVSF codes;
FIG. 4 is a diagram illustrating a transmitter structure of a UE according to
an embodiment of the present invention; and
FIG. 5 is a diagram illustrating a PAPR comparison result between
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physical channels according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Several preferred embodiments of the present invention will now be
described in detail with reference to the annexed drawings. In the following
description, a detailed description of known functions and configurations
incorporated herein has been omitted for conciseness.
The present invention proposes an OVSF code and I/Q channel allocation
method for minimizing an increase in PAPR of an uplink transmission signal in
a
WCDMA system supporting EUDCH data service. That is, the present invention
proposes an OVSF code and I/Q channel allocation method optimized for the case
where an E-DPCCH which is a control channel and an E-DPDCH which is a data
channel, for transmission of EUDCH packet data, are transmitted in addition to
the existing physical channels. In order to increase a EUDCH data rate and
minimize an increase in PAPR, the present invention proposes an OVSF code and
I/Q channel allocation method for minimizing the PAPR increase while
maintaining orthogonality between the existing DPCCH, DPDCH and HS-
DPCCH.
In the existing Re1-5 WCDMA standard, OVSF code and I/Q channel
allocation for an HS-DPCCH channel is achieved so as to reduce a PAPR
considering the maximum number of transmittable DPDCHs, determined during
setup of a radio link between a UE and a Node B.
Therefore, OVSF code and I/Q channel allocation for an E-DPDCH and
an E-DPCCH, proposed in the present invention, is achieved considering the
maximum number of DPDCHs transmittable in the radio link and
transmission/non-transmission of an HS-DPCCH, for the Re1-5 physical channels.
In the EUDCH service, several E-DPDCH physical channels can be
simultaneously transmitted because they support high-data rate transmission.
However, it is generally sufficient that a single E-DPCCH, which is a physical
control channel, is transmitted.
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That is, in order to reduce a PAPR increase of an uplink transmission
signal, the present invention supports a EUDCH considering backward
compatibility with the existing WCDMA system. The reason is because serious
problems may occur in initial call setup or handover processes when Node Bs
are
inconsistent with each other in terms of a version due to incompatibility for
DPDCH and DPCCH standard.
In other words, the present invention proposes an OVSF code and I/Q
channel allocation method optimized to minimize the PAPR increase for
EUDCH-related physical channels while maintaining the existing Re1-5 WCDMA
standard for the DPDCH and the DPCCH which are core uplink physical
channels.
= First, assuming that the existing uplink channels such as a DPCCH, a
DPDCH and an HS-DPCCH undergo OVSF code and I/Q channel allocation as
defined in the current standard in an OVSF code and I/Q channel allocation
method by maintaining full compatibility with the existing Re1-5 WCDMA
= system, the present invention proposes an OVSF code and I/Q channel
allocation
method optimized for the case where an E-DPCCH and an E-DPDCH which are
physical channels for transmission of EUDCH packet data are additionally
transmitted on that assumption.
Second, the case where compatibility with the HS-DPCCH is partially
lost while compatibility with the existing DPDCH and DPCCH is maintained will
be taken into consideration. In the current Re1-5 WCDMA standard, if the
maximum number of transmittable DPDCHs is one, the HS-DPCCH is
transmitted on a Q channel using an OVSF code (256, 64). In this case, because
an E-DPDCH cannot use an OVSF code (4, 1) on the Q channel, a maximum
EUDCH data rate is limited accordingly. In order to solve the problem, the
present invention proposes a code allocation rule for the HS-DPCCH, E-DPCCH
and E-DPDCH so as to enable the E-DPDCH to use the OVSF code (4, 1) on the
Q channel and reduce a PAPR of UE's transmission signal.
Third, in a Re1-6 standard, even a EUDCH stand-alone case in which no
DPDCH is transmitted and only the E-DPDCH is transmitted in the uplink is
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taken into consideration. Therefore, the present invention presents an OVSF
code
and I/Q channel allocation rule for the HS-DPCCH for the EUDCH stand-alone
case.
In the foregoing methods, I/Q channel and OVSF code allocation for the
HS-DPCCH depends on the maximum number of transmittable DPDCH channels,
and the number of E-DPDCH channels does not affect the allocation rule for the
HS-DPCCH. This is because the E-DPDCH is not always transmitted, but
transmitted only when there is data in a EUDCH data buffer of a UE. Therefore,
in terms of a PAPR, it is preferable to define an OVSF code and I/Q channel
allocation rule for the HS-DPCCH considering only the DPDCH according to the
current standard.
FIG. 4 is a diagram illustrating a transmitter structure of a UE according
to an embodiment of the present invention.
1. DPCCH
A DPCCH is allocated an OVSF code (256, 0) on a Q channel according
to the existing Re1-99 and Rd1-5 channel allocation rules. The (256, 0) is
equal to
an OVSF code Cch,256,0 illustrated in FIG. 3. That is, in FIG 4, the DPCCH is
multiplied by the OVSF code Cch,256,0 for spreading after being BPSK-
modulated,
and then multiplied by a transmission gain 13c. The
is set by a network
according to a rate or a required quality-of-service level of data transmitted
by a
UE.
The DPCCH signal is added to other channel signals transmitted through
a Q channel, multiplied by a scrambling code Sdpch,n, and then transmitted via
an
antenna through a transmission pulse forming filter and an RF stage.
2. DPDCH
According to the channel allocation rule defined in the existing standard,
if an SF value of a DPDCH is denoted by SFDpDcH, the DPDCH is spread by an
OVSF code (SEoppcit, SFDp0ch/4) on an I channel. In FIG. 4, cd denotes an OVSF
code for a DPDCH. In the present invention, it is assumed that when physical
channels related to the EUDCH service are transmitted together with the DPDCH,
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only a maximum of one DPDCH channel is transmitted.
3. HS-DPCCH
Also, this follows the existing Re1-5 standard and is transmitted only
when HSDPA service is achieved in a downlink. As can be seen in FIG. 4, when
only one DPDCH is transmitted in the uplink, an HS-DPCCH is spread by an
OVSF code (256, 64) on a Q channel.
4. E-DPCCH
An E-DPCCH, a physical control channel for EUDCH service, transmits
a buffer state of a UE, or transmits uplink transmission power, uplink
transmission power margin, and channel state information (CSI), which are
needed by a Node B to estimate an uplink channel condition. The E-DPCCH
transmits a Transport Format and Resource Indicator (E-TFRI) for EUDCH
service transmitted over the E-DPDCH.
If an SF value of an E-DPCCH is denoted by SFE_DpccH, the E-DPCCH is
spread by an OVSF code (SFE_DpccH, 1) on an I channel. Herein, OVSF codes and
I/Q channels are allocated to the E-DPCCH in a free way.
In an alternative method, the E-DPCCH uses an OVSF code (SFE-DPCCI-13
1) on a Q channel, unlike the DPCCH transmitted using an OVSF code (256, 1)
on an I channel.
In another alternative method, the E-DPCCH is allocated to a Q channel
when no DPDCH is set up and an HS-DPCCH is set up. In this case, an OVSF
code (SFE.DpccH, 1) or (SFE-DPCCI-1, SFE-DPCCI-1/8) is suitable for the E-
DPCCH.
In further another alternative method, when no DPDCH is set up, the E-
DPCCH can be allocated to the Q channel regardless of setup/non-setup of the
HS-DPCCH. In this case, an OVSF code (SFE_Dpccll, 1) or (SFE.Dpcm, SFE_
opccH/8) is suitable for the E-DPCCH.
Such a rule is always available regardless of transmission/non-
transmission of the HS-DPCCH and the number of E-DPDCH channels. In this
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case, 8, 16, 32, 64, 128 and 256 are available for the SFE_DpccH, and an SFE-
DPCCH
value to be actually used is determined considering the amount of information
to
be transmitted over the E-DPCCH.
In the case where no DPDCH is set up and an HS-DPCCH is set up for an
I channel (256, 1), even if SFE_Dpcar--256, the E-DPCCH cannot be allocated
=(SFE_Dpccub 1). Therefore, the E-DPCCH cannot be allocated for I channels
(SFE.
DPCCH, 2) to (SFE-DPccth SFE.opccH/8). That is, allocating the E-DPCCH for the
I
channels (SFE-DPccn, 2) to (SFE-Dpccii, SFE-DPccu/8) is most efficient in
achieving a
low PAR value. Herein, 32, 64, 128 and 256 are available for the SFE-DPCCH.
Referring to FIG. 4, a EUDCH transmission controller 402 transmits
control information through the E-DPCCH, which is needed by a Node B to
receive an E-DPDCH. In FIG. 4, cch,sF,i denotes an OVSF code for the E-DPCCH,
and is multiplied by a transmission symbol so that the corresponding channel
should be orthogonal with other physical channels. In addition, a transmission
gain r3E-DPCCH of the E-DPCCH, like those of other physical channels, is set
according to a rate or a required quality-of-service level of data transmitted
by a
UE.
5. E-DPDCH
An E-DPDCH, a dedicated physical data channel for the EUDCH service,
transmits EUDCH packet data using a data rate determined based on scheduling
information provided from the Node B. The E-DPDCH supports not only BPSK
but also QPSK and 8PSK in order to increase a data rate while maintaining the
number of simultaneously transmitted spreading codes.
Referring back to FIG. 4, the E-DPDCH simultaneously transmits two
channels of an E-DPDCH1 and an E-DPDCH2, by way of example. Herein, it is
obvious that the number of E-DPDCH physical channels in use depends on a
, transfer rate of EUDCH packet data. In addition, the EUDCH
transmission
controller 402 determines the number of simultaneously transmitted E-DPDCH
channels and an SF value.
In other words, when a data rate is low, an E-DPDCH is spread with an
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OVSF code having a relatively large SF value so that it can be transmitted
with
one E-DPDCH. However, when a data rate is high, an SFE-DPCCH value is set to 4
or 2 so that EUDCH packet data is transmitted through one or two E-DPDCH
channels.
That is, a EUDCH packet transmitter 404 transmits EUDCH transmission
data through an E-DPDCH1 under the control of the EUDCH transmission
controller 402. Alternatively, even the E-DPDCH2 is allocated for the
transmission when necessary. A EUDCH data buffer 400 is a buffer for storing
EUDCH data to be transmitted. The EUDCH data to be transmitted through the
E-DPDCH channels is delivered to the EUDCH packet transmitter 404 under the
control of the EUDCH transmission controller 402.
A description will now be made of methods for allocating OVSF codes
and 1/Q channels for E-DPDCHs according to several embodiments of the present
invention.
First Embodiment
A first embodiment proposes methods for allocating OVSF codes and I/Q
channels for the E-DPDCHs without considering DPDCHs. The proposed
methods can reduce a PAPR by appropriately adjusting the minimum spreading
gain value for E-DPDCHs and the number of transmission channels according to
a EUDCH data rate. Herein, for convenience of description, the methods will be
divided into Method A, Method B and Method C considering an SFE_DpDcH set
based on a data rate.
Method A corresponds to a case where an SFE-DPDCH for E-DPDCHs is set
to 4 or larger.
1. One E-DPDCH Channel Transmitted
An E-DPDCH1 transmits EUDCH transmission symbols through a Q
channel using an OVSF code (SFE_DpDcH, SFE_DpDcH/2). Herein, 4, 8, 16, 32, 64,
128 and 256 are available for the SFE-DPDCH= In FIG. 4, cedi denotes an OVSF
code
used for the E-DPDCH1. The E-DPDCH1 allocated an OVSF code in this way
satisfies orthogonality with other physical channels. That is, compared with a
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DPDCH transmitted on an I channel, the E-DPDCH1 can reduce its PAPR as it is
transmitted on the Q channel.
2. Two E-DPDCH Channels Transmitted
When an SFE-DPDCH for an E-DPDCH1 and an E-DPDCH2 is 4, the E-
DPDCH1 and the E-DPDCH2 are spread with an OVSF code (4, 2) and then
simultaneously transmitted through a Q channel and an I channel, respectively.
That is, the E-DPDCH1 is allocated to the Q channel, and the E-DPDCH2 is
allocated to the I channel. Herein, the EUDCH packet data is transmitted with
a
modulation scheme having a 4th order or higher, such as QPSK, 8PSK and
16QAM.
For example, when QPSK modulation is used, symbols transmitted
through the E-DPDCH1 and the E-DPDCH2 are transmitted in four possible
combinations of ( 1 , 1), and when 8PSK is used, symbols transmitted through
the E-DPDCH1 and the E-DPDCH2 are transmitted in eight possible
combinations of ( (0, -J) and ( 1, 1).
If a desired EUDCH data rate cannot be achieved even though the two
channels of the E-DPDCH1 and the E-DPDCH 2 are simultaneously transmitted
using the SFE-DpDCH=4, it is possible to enable transmission at a higher data
rate
by setting the SFE-DPDCH to 2. That is, if an SFE-DPDCH for the E-DPDCH1 and
the
E-DPDCH2 is 2, the E-DPDCH1 and the E-DPDCH2 are spread with an OVSF
code (2, 1) and then simultaneously transmitted on a Q channel and an I
channel,
respectively.
When it is necessary to transmit several E-DPDCH physical channels in
this way, it is possible to remarkably reduce a PAPR by halving the number of
E-
DPDCH channels being transmitted, as compared with the case where the
minimum spreading gain is 4.
Method B is similar to Method A described above, but allocates OVSF
codes such that when only an E-DPDCHI is transmitted, SFE_DpDcH is set to a
minimum of 2.
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1. One E-DPDCH Channel Transmitted
When only the E-DPDCH1 is transmitted, 2, 4, 8, 16, 32, 64, 128 and 256
are available for the SFE.DPDCH. The E-DPDCH1 is allocated to a Q channel
using
an OVSF code (SFE-DPDCH, SFE-DPncH/2)
2. Two E-DPDCH Channels Transmitted
The E-DPDCH1 and the E-DPDCH2 are spread with an OVSF code (2,
1) and then simultaneously transmitted on a Q channel and an I channel,
respectively. In this case, EUDCH packet data is transmitted with a modulation
scheme having a 4th order or higher, such as QPSK, 8PSK and 16QAM.
Method C is similar to Method A described above, but allocates OVSF
codes such that SFE.DpDcH for the E-DPDCH1 is set to 2 and SFE-DPDCH for the E-
DPDCH2 is set to 4, if a desired EUDCH data rate cannot be achieved even
though the two channels of the E-DPDCH1 and the E-DPDCH 2 are
simultaneously transmitted using the SFE-DPDCH=4.
1. One E-DPDCH Channel Transmitted
When an SFE.DpDCH for E-DPDCHs is 4 or larger, EUDCH transmission
symbols are transmitted through a Q channel using an OVSF code (SFE_DpDcH,
SFE_DPD42). Herein, 4, 8, 16, 32, 64, 128 and 256 are available for the SFE-
DPCCH.
2. Two E-DPDCH Channels Transmitted
When an SFE.DpDCH for the E-DPDCH1 and the E-DPDCH2 is 4, the E-
DPDCH1 and the E-DPDCH2 are spread with an OVSF code (4, 2) and then
simultaneously transmitted through a Q channel and an I channel, respectively.
If
a desired EUDCH data rate cannot be achieved even though the two channels of
the E-DPDCH1 and the E-DPDCH 2 are simultaneously transmitted, an SFE_
DPDCH for the E-DpDC1-11 and an SFE-DPDCH for the E-DPDCH2 are set to
different
values.
That is, as an SFE-DPDCH for the E-DPDCH1 is set to 2 and an SFE_DpDcH
for the E-DPDCH2 is set to 4, data carried on the respective channels
independently undergoes BPSK modulation before being transmitted. Therefore,
symbols transmitted on the E-DPDCH1 and the E-DPDCH2 are spread with
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OVSF codes (2, 1) and (4, 2) on a Q channel and an I channel, respectively,
before being transmitted.
In addition, when a data rate cannot be achieved in the foregoing manner,
the SFE_HpHcH for the E-DPDCH1 is set to 2 and the SFE-DPDCH for the E-DPDCH2
is set to 2 for transmission. That is, the E-DPDCH2 and the E-DPDCH1 are
spread with an OVSF code (2, 1) and then simultaneously transmitted on the I
channel and the Q channel, respectively. In this case, the EUDCH packet data
can
be transmitted with a modulation scheme having a 4th order or higher, such as
QPSK, 8PSK and 16QAM.
Method D is a method for allocating an OVSF code (4, 1) to an additional
E-DPDCH to increase a EUDCH packet data rate when a DPDCH and an HS-
DPCCH are not transmitted or when an OVSF code generated from an OVSF
code (4, 0) is used even though the HS-DPCCH is transmitted. This is because
the
HS-DPCCH is transmitted only for the HSDPA service. In addition, this is
because when there is no data to be transmitted over a DPDCH, the DPDCH is
occasionally used only for transmission of signaling information and may not
be
transmitted for the other time. In the post-Rd1-5 WCDMA standard, there is a
possible case where the DPDCH is not set up and only the E-DPDCH is set up.
1. Two or Less E-DPDCH Channels Transmitted
The foregoing Method A, Method B, or Method C can be used.
2. Three E-DPDCH Channels Transmitted
When an HS-DPCCH is not transmitted, an E-DPDCH3 channel is
= transmitted through a Q channel using an OVSF code (4, 1).
Alternatively, when the HS-DPCCH is transmitted and the DPDCH is not
transmitted, the E-DPDCH3 channel is transmitted through an I channel using
the
OVSF code (4, 1).
3. Four or More E-DPDCH Channels Transmitted
The I channel and the Q channel both use the OVSF code (4, 1) for
transmission. This is applied when the OVSF code (4, 1) is not used by the
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DPDCH and the HS-DPCCH.
In other words, when both of the HS-DPCCH and the DPDCH are not
transmitted, third and fourth E-DPDCH channels are transmitted through the I
channel and the Q channel using the OVSF code (4, 1), respectively. Even when
the DPDCH is not set up and the HS-DPCCH is transmitted using an OVSF code
generated from the OVSF code (4, 0), the OVSF code (4, 1) is never used in the
I
and Q channels. Therefore, it is possible to transmit the third and fourth E-
DPDCH channels on the I/Q channels using the OVSF code (4, 1).
Second Embodiment
A second embodiment proposes methods for applying an OVSF code and
I/Q channel allocation rule for the E-DPDCH in a different way considering
setup/non-setup of an HS-DPCCH.
The second embodiment provides a method for first allocating an E-
DPDCH to an I channel when the HS-DPCCH is set for an OVSF code (256, 64)
in a Q channel, thereby reducing a PAPR. The second embodiment is
advantageous in that it can remarkably reduce a PAPR when an HS-DPCCH has
higher power than that of a DPDCH as a UE is located in the vicinity of a cell
boundary.
When the HS-DPCCH is not .set up, OVSF codes are allocated in the
following method.
1. One E-DPDCH Transmitted
An E-DPDCH transmits EUDCH transmission symbols on a Q channel
using an OVSF code (SFE_DpDcH, SFE-DPDcH/4). Herein, 4, 8, 16, 32, 64, 128,
256
and 512 are available for the SFE-DPDCH.
If a EUDCH data rate cannot be fully achieved even though the SFE..
DpDcH=4 is used, the E-DPDCH uses on the Q channel an OVSF code (2, 1) with
SFE-DPDCH=2 instead of its OVSF code (SFE-oPncn, SFE-DPDcH/4).
2. Two E-DPDCHs Transmitted
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When an SFE_DpDcH for E-DPDCHs is set to 2, an E-DPDCH1 is
transmitted on a Q channel using an OVSF code (2, 1), and an E-DPDCH2 is
transmitted on an I channel using an OVSF code (2, 1).
Alternatively, the E-DPDCH1 is transmitted on the Q channel using an
OVSF code (2, 1), and the E-DPDCH2 is transmitted on the I channel using an
OVSF code (4, 2). In this case, if a desired EUDCH data rate cannot be
achieved,
an SFE-DPncH for the E-DPDCH2 is set to 2 and an OVSF code (2, 1) is used
instead of the OVSF code (4, 2) for transmission of the E-DPDCH2.
3. Three E-DPDCHs Transmitted
When an E-DPDCH1 is transmitted on a Q channel using an OVSF code
(2, 1) and an E-DPDCH2 is transmitted on an I channel using an OVSF code (2,
1), an E-DPDCH3 is transmitted on the Q channel using an OVSF code (4, 1).
4. Fourth E-DPDCHs Transmitted
An E-DPDCH4 is transmitted on an I channel using an OVSF code (4, 1).
Herein, the case where an OVSF code (4, 1) can be used on both the I
channel and the Q channel corresponds to the case where the OVSF code (4, 1)
is
unused by a DPDCH and an HS-DPCCH. That is, in the case where no DPDCH
is set up, or in the case where a DPDCH is equal to an E-DPDCH in radio frame
length even though the DPDCH is set up, an E-DPDCH4 is transmitted on an I
channel using an OVSF code (4, 1) in addition to the E-DPDCH1, E-DPDCH2,
and E-DPDCH3 in a transmission time interval (TTI) for which the DPDCH is
not transmitted.
However, when an HS-DPCCH is set for (Q, 256, 64), an OVSF code
allocation method is as follows.
1. One E-DPDCH Transmitted
An E-DPDCH1 transmits EUDCH transmission symbols on an I channel
using an OVSF code (SFE_DPDCH, SFE-DPDCH/2). Herein, 2, 4, 8, 16, 32, 64, 128,
256 and 512 are available for the SFE_DPDCH=
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2. Two E-DPDCHs Transmitted
An E-DPDCH1 is transmitted on an I channel using an OVSF code (2, 1),
and an E-DPDCH2 is also transmitted on a Q channel using an OVSF code (2, 1).
Third Embodiment
A third embodiment uses the same OVSF code allocation method as that
of the second embodiment when an HS-DPCCH is not set up. However, the third
embodiment is characterized in that it first allocates an E-DPDCH to a Q
channel
instead of an I channel on which the HS-DPCCH is set for (Q, 256, 64).
When the HS-DPCCH is not set up, the third embodiment uses the same
OVSF code allocation method as that of the second embodiment.
However, when the HS-DPCCH is set for (Q, 256, 64), the following
OVSF code allocation method is used.
1. One E-DPDCH Transmitted
An E-DPDCH1 uses (SFE-DPocn, SFE-DPncit/2) on a Q channel, and 2, 4, 8,
16, 32, 64, 128, 256 and 512 are available for the SFE-DPDCH.
2. Two E-DPDCHs Transmitted
When an SFE-DPDCH for E-DPDCHs is set to 2, an E-DPDCH1 is
transmitted on a Q channel using an OVSF code (2, 1), and an E-DPDCH2 is
transmitted on an I channel using an OVSF code (2, 1).
Alternatively, the E-DPDCH1 is transmitted on the Q channel using an
OVSF code (2, 1), and the E-DPDCH2 is transmitted on the I channel using an
OVSF code (4, 2). In this case, if a desired EUDCH data rate cannot be
achieved,
an SFE-DPDCH for the E-DPDCH2 is set to 2 and an OVSF code (2, 1) is used
instead of the OVSF code (4, 2) for transmission of the E-DPDCH2.
3. Three E-DPDCHs Transmitted
In the case where no DPDCH is set up, or in the case where a DPDCH is
equal to an E-DPDCH in radio frame length even though the DPDCH is set up, an
E-DPDCH3 is transmitted on a Q channel using an OVSF code (4, 1) in addition
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to the E-DPDCH1 and E-DPDCH2 transmitted on I and Q channels using an
OVSF code (2, 1), in a TTI for which the DPDCH is not transmitted on the I
channel.
Fourth Embodiment
A fourth embodiment proposes a method for reducing a PAPR and
efficiently using OVSF codes for the case where no DPDCH ,is set up or the
case
where an E-DPDCH is equal to a DPDCH, even if it is set up, in radio frame
length, in the case where an HS-DPCCH is set for an OVSF code (256, 64) on a
Q channel. An I/Q channel and OVSF code allocation method used for E-
DPDCHs varies according to presence/absence of DPDCHs transmitted in the
current TTI.
1. One E-DPDCH Transmitted
When DPDCHs are transmitted in the current TTI, an E-DPDCH1 uses
(SFE-DpDcH, SFE-DpDcti/2) on a Q channel, and 2, 4, 8, 16, 32, 64, 128, 256
and 512
are available for the SFE-DPDCH.
However, when no DPDCH is transmitted in the current TTI, an OVSF
code (SFE-DPDCH, SFE-DPDCH/4) is used on an I channel, and 4, 8, 16, 32, 64,
128,
256 and 512 are available for the SFE-DPDcH. In this case, in order to further
increase a EUDCH data rate, the E-DPDCH is transmitted using an OVSF code
(2, 1) instead of the OVSF code (SFE-DPDcH, SFE-DPDcH/4).
2. Two E-DPDCHs Transmitted
When an SFE-DPDCH for E-DPDCHs is set to 2, an E-DPDCH1 is
transmitted on a Q channel using an OVSF code (2, 1), and an E-DPDCH2 is
transmitted on an I channel using an OVSF code (2, 1).
Alternatively, the E-DPDCH1 is transmitted on the Q channel using an
OVSF code (2, 1), and the E-DPDCH2 is transmitted on the I channel using an
OVSF code (4, 2). In this case, if a desired EUDCH data rate cannot be
achieved,
an SFE-DPDCH for the E-DPDCH2 is set to 2 and an OVSF code (2, 1) is used
instead of the OVSF code (4, 2) for transmission of the E-DPDCH2.
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3. Three E-DPDCHs Transmitted
In addition to the E-DPDCH1 and the E-DPDCH2 transmitted on the Q
and I channels using the OVSF code (2, 1), an E-DPDCH is transmitted on the I
channel using an OVSF code (4, 1) when no DPDCH is transmitted in the current
TTI.
Fifth Embodiment
A fifth embodiment proposes a method for allocating E-DPDCHs when
no DPDCH is set up. For the E-DPDCHs, the fifth embodiment has a basic
concept of allocating an E-DPDCH1 to opposite I/Q channels of the I/Q channels
on which an HS-DPDCH is transmitted, and can reduce a PAPR when a channel
gain factor for the HS-DPCCH is high.
When the HS-DPCCH is not set up, an E-DPDCH allocation method is as
follows.
1. One E-DPDCH Transmitted
An E-DPDCH1 transmits EUDCH transmission symbols on an I channel
using an OVSF code (SFE-oPncii, SFE-DpncH/4). Herein, 4, 8, 16, 32, 64, 128,
256
and 512 are available for the SFE.DpDcH. In this case, if a EUDCH data rate
cannot
be fully achieved even though the SFE_DpDcH is set to 4, the SFE_Dppcii is set
to 2
and the EUDCH transmission symbols are transmitted on the I channel using an
OVSF code (2, 1) instead of the OVSF code (SFE-DPncit, SFE-DPncH/4).
2. Two E-DPDCHs Transmitted
An E-DPDCH1 is transmitted on an I channel using an OVSF code (2, 1),
and an E-DPDCH2 is transmitted on a Q channel using an OVSF code (2, 1).
3. Three or More E-DPDCHs Transmitted
In addition to the E-DPDCH1 and the E-DPDCH2, an E-DPDCH3 and an
E-DPDCH4 transmit EUDCH transmission symbols on I and Q channels using an
OVSF code (4, 1).
However, when the DPDCH is not set up and an HS-DPCCH is set up,
the HS-DPCCH is likely allocated for the I channel.
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1. One E-DPDCH Transmitted
An E-DPDCH transmits EUDCH transmission symbols on a Q channel
using an OVSF code (SFE-oPocn, SFE-oPocH/4). Herein, 4, 8, 16, 32, 64, 128,
256
and 512 are available for the SFE-DPDCI-1. If a EUDCH data rate cannot be
fully
achieved even though the SFE-DPDCF1=4 is used, the SF is set to 2 and the Q
channel uses an OVSF code (2, 1).
2. Two E-DPDCHs Transmitted
An E-DPDCH1 is transmitted on a Q channel using an OVSF code (2, 1),
and an E-DPDCH2 is transmitted on an I channel using an OVSF code (2, 1).
3. Three or More E-DPDCHs Transmitted
In addition to the E-DPDCH1 and the E-DPDCH2 transmitted on the Q
and I channels using an OVSF code (2, 1), an E-DPDCH3 and an E-DPDCH4
additionally transmit EUDCH transmission symbols on both the I and Q channels
using an OVSF code (4, 1).
Referring back to FIG. 4, the EUDCH transmission controller 402
transmits UE's data buffer state and CSI, required for Node B's scheduling
control, to the Node B through the E-DPCCH. The EUDCH transmission
controller 402 determines an E-TFRI and transmits the determined E-TFRI to the
Node B through the E-DPCCH. The E-TFRI is determined using a possible
maximum data rate.
The EUDCH packet transmitter 404 receives packet data determined
based on the E-TFRI from the EUDCH data buffer 400. The received packet data
undergoes channel coding and modulation using the E-TFRI, and then transmitted
to the Node B through the E-DPDCH1 and E-DPDCH2 channels according to an
embodiment of the present invention.
Data on the DPDCH is spread at a chip rate using an OVSF code cd in a
multiplier 422, and multiplied by a channel gain iid in a multiplier 424. The
DPDCH data multiplied by the channel gain pd is input to a summer 426.
Control information on an E-DPCCH is spread in a multiplier 406 at a
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chip rate using an OVSF code Celi,SZI, i.e., (SFE-DPccx, 1), to maintain
orthogonality with other physical channels. Thereafter, the output of the
multiplier 406 is multiplied by a channel gain Pee in a multiplier 408. The E-
DPCCH control information multiplied by the channel gain
is input to the
summer 426.
Packet data provided from the EUDCH packet transmitter 404 is
converted into a complex symbol stream I+jQ, and then delivered to a
multiplier
446 and a multiplier 416 as I and Q channel components, respectively. The
multiplier 446 spreads the packet data into an I channel component of a
modulation symbol with an OVSF code Ced2 at a chip rate. The output of the
multiplier 446 is multiplied by a channel gain B
ed2 in a multiplier 448. The
summer 426 forms an I channel by summing up the DPDCH data, the E-DPCCH
control information, and the E-DPDCH2 data.
Control information on the DPCCH is spread in a multiplier 428 at a chip
rate using an OVSF code (256, 0), i.e., Ceh,256,0, and then multiplied by a
channel
gain r3, in a multiplier 430. The DPCCH control information multiplied by the
channel gain f3c is input to a summer 436.
Control information on the HS-DPCCH is spread in a multiplier 432
using an OVSF code (256, 64), i.e., Cch,256,64) at a chip rate, and then
multiplied by
a channel gain Ph, in a multiplier 434.
A Q channel component of a EUDCH packet data modulation symbol
provided from the EUDCH packet transmitter 404 is spread in a multiplier 416
with an OVSF code Cedi at a chip rate. The output of the multiplier 416 is
multiplied by a channel gain B
edl in a multiplier 418. The summer 436 forms a Q
channel by summing up the DPCCH control information, the HS-DPCCH control
information, and the E-DPDCH1 data. The output of the summer 436 is
multiplied by an imaginary number in a multiplier 438, and then delivered to a
summer 440.
The summer 440 forms one complex symbol stream by summing up the
output of the summer 426 and the output of the multiplier 438, and delivers
the
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complex symbol stream to a multiplier 450. The multiplier 450 scrambles the
complex symbol stream using a scrambling code Sdpcm. The scrambled complex
symbol stream is converted into a pulse signal by a pulse shaping filter 452,
and
then delivered to the Node B via an antenna 456 through an RF module 454.
FIG. 5 is a diagram illustrating a comparison between physical channels
in terms of a PAPR reduction effect by FIG. 4.
In FIG. 5, reference numeral 40 represents the case where a method
proposed by the present invention is used, and reference numerals 41 and 42
represent the cases where different OVSF codes or different I/Q channels are
allocated for an E-DPCCH. Herein, the PAPR result has been obtained through
simulation using the transmission pulse shaping filter 452 and the scrambling
code, specified in the Rd1-5 WCDMA standard, and the channel gain 13 is
generally set under discussion of the EUDCH technique.
Referring to FIG. 5, the case 40 proposed by the present invention is
superior to the case 41 in terms of a PAPR reduction effect by about 0.7 dB.
In
addition, the case 40 proposed by the present invention is superior to the
case 42
in terms of a PAPR reduction effect by about 0.12 dB. That is, the proposed
OVSF code and I/Q channel allocation method for the E-DPCCH and the E-
DPDCH can achieve a relatively low PAPR.
A description will now be made of an OVSF code and I/Q channel
allocation method for an E-DPCCH and an E-DPDCH considering
transmission/non-transmission of an HS-DPCCH when compatibility with the
existing Re1-5 standard is maintained and at least one DPDCH is transmitted,
according to sixth to ninth embodiments.
Sixth Embodiment
1. One or More DPDCHs being Transmittable and HS-DPCCH being not
Transmitted
A method of allocating I/Q channels and OVSF codes for a DPCCH and a
DPDCH according to the current standard are illustrated in Table 1.
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Table 1
Channel Allocation
DPCCH (Q, 256, 0)
DPDCH (I, SF, SF/4)
That is, a DPCCH channel is transmitted on a Q channel using an OVSF
code (256, 0), and a DPDCH can be allocated to an I channel with an OVSF code
(SFDppoi, SFoppcii/4). Here, 4, 8, 16, 32, 64, 128, 256 and 512 are available
for
the SFDPDCH.
A method of allocating I/Q channels and OVSF codes for an E-DPCCH
and E-DPDCHs in the present invention considering compatibility with the
current standard of Table 1 is illustrated in Table 2.
Table 2
Channel Allocation
E-DPCCH (I, SFE-DpccH, 1)
E-DPDCH1, E-DPDCH2, (Q, SF, SF/4), (1,4, 3)
E-DPDCH3, E-DPDCH4, (Q, 4, 3), (I, 4, 2)
E-DPDCH5 (Q, 4, 2)
Here, 8, 16, 32, 64, 128 and 256 are available for the SFE-DPCCH for the E-
DPCCH, and 4, 8, 16, 32, 64, 128, 256 and 512 are available for the SFE-DPDCH
for
the E-DPDCHs.
As illustrated in Table 2, if a maximum of 5 E-DPDCH channels can be
transmitted and SF-4 is applied to an E-DPDCH1, the E-DPDCH1 is transmitted
on a Q channel using an OVSF code (4, 1), and an E-DPDCH2 is transmitted on
an I channel with an OVSF code (4, 3). In addition, an E-DPDCH3 is transmitted
on a Q channel using an OVSF code (4, 3), and an E-DPDCH4 is transmitted on
the I channel using an OVSF code (4, 2). Finally, an E-DPDCH5 is transmitted
on
the Q channel using an OVSF code (4, 2).
2. One or More DPDCHs being Transmittable and HS-DPCCH being
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Transmitted
A method of allocating I/Q channels and OVSF codes for a DPCCH, a
DPDCH, and an HS-DPCCH according to the current standard are illustrated in
Table 3.
Table 3
Channel Allocation
DPCCH (Q, 256, 0)
DPDCH (I, SF, SF/4)
HS-DPCCH (Q, 256, 64)
A method of allocating I/Q channels and OVSF codes for an E-DPCCH
and E-DPDCHs in the present invention considering compatibility with the
current standard of Table 3 is illustrated in Table 4.
Table 4
Channel Allocation
E-DPCCH (I, SFE-DPCCH, 1)
E-DPDCH1, E-DPDCH2, (Q, SF, SF/4+SF/2), (I, 4, 3)
E-DPDCH3, E-DPDCH4 (Q, 4, 2), (I, 4, 2)
Here, 8, 16, 32, 64, 128 and 256 are available for the SFE-DPCCH for the E-
DPCCH, and 4, 8, 16, 32, 64, 128, 256 and 512 are available for the SFE-DPDCH
for
the E-DPDCHs.
In this case, if a maximum of 4 E-DPDCH channels can be transmitted
and SFE-DPDCH=4 is used, an E-DPDCH1 and an E-DPDCH2 are allocated (Q, 4,
3) and (I, 4, 3), respectively. An E-DPDCH3 is transmitted on a Q channel
using
an OVSF code (4, 2), and an E-DPDCH4 is transmitted on an I channel using an
OVSF code (4, 2).
3. A Maximum of 2 DPDCHs being Transmittable and HS-DPCCH being
not Transmitted
A method of allocating I/Q channels and OVSF codes for a DPCCH and
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DPDCHs according to the current standard is illustrated in Table 5.
Table 5
Channel Allocation
DPCCH (Q, 256, 0)
DPDCH1, DPDCH2 (I, SF, SF/4), (Q, 4, 1)
A method of allocating I/Q channels and OVSF codes for an E-DPCCH
and E-DPDCHs in the present invention considering compatibility with the
current standard of Table 5 is illustrated in Table 6.
Table 6
Channel Allocation
E-DPCCH (I, SFE-DPCCH, 1)
E-DPDCH1, E-DPDCH2, (Q, SF, SF/4+SF/2), (1, 4, 3)
E-DPDCH3, E-DPDCH4 (Q, 4, 2), (I, 4, 2)
Here, 8, 16, 32, 64, 128 and 256 are available for the SFE-DPCCH for the E-
DPCCH, and 4, 8, 16, 32, 64, 128, 256 and 512 are available for the SFE-oPocH
for
the E-DPDCHs.
In this case, if a maximum of 4 E-DPDCH channels can be transmitted
and SFE-DPDCH=4 is used, an E-DPDCH1 and an E-DPDCH2 are transmitted using
(Q, 4, 3) and (I, 4, 3), respectively. An E-DPDCH3 is transmitted on a Q
channel
using an OVSF code (4, 2), and an E-DPDCH4 is transmitted on an I channel
using an OVSF code (4, 2).
4. A Maximum of 2 DPDCHs being Transmittable and HS-DPCCH being
Transmitted
A method of allocating I/Q channels and OVSF codes for a DPCCH, a
DPDCH and an HS-DPCCH according to the current standard is illustrated in
Table 7.
Table 7
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Channel Allocation
DPCCH (Q, 256, 0)
DPDCH (I, SF, SF/4)
HS-DPCCH (Q, 256, 64)
A method of allocating I/Q channels and OVSF codes for an E-DPCCH
and E-DPDCHs in the present invention considering compatibility with the
current standard of Table 7 is illustrated in Table 8.
Table 8
Channel Allocation
E-DPCCH (Q, SFE-Dpcali SFr-Iwo-T/8)
E-DPDCH1, E-DPDCH2, (I, SF, SF/4+SF/2), (Q, 4, 8)
E-DPDCH3, E-DPDCH4 (I, 4, 2), (Q, 4, 2)
Here, 64, 128 and 256 are available for the SFE-DPccH for the E-DPCCH,
and 4, 8, 16, 32, 64, 128, 256 and 512 are available for the SFE-DPDCH for the
E-
DPDCHs.
In this case, if a maximum of 4 E-DPDCH channels can be transmitted
and SF-4 is used, an E-DPDCH1 and an E-DPDCH2 are allocated (I, 4, 3) and
(Q, 4, 3), respectively. An E-DPDCH3 is transmitted on an I channel using an
OVSF code (4, 2), and an E-DPDCH4 is transmitted on a Q channel using an
OVSF code (4, 2).
5. A Maximum of 3 DPDCHs being Transmittable and HS-DPCCH being
not Transmitted
A method of allocating I/Q channels and OVSF codes for a DPCCH and
DPDCHs according to the current standard is illustrated in Table 9.
Table 9
Channel Allocation
DPCCH (Q, 256, 0)
DPDCH1, DPDCH2, (I, SF, SF/4), (Q, 4, 1)
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DPDCH3 (I, 4, 3)
A method of allocating I/Q channels and OVSF codes for an E-DPCCH
and E-DPDCHs in the present invention considering compatibility with the
current standard of Table 9 is illustrated in Table 10.
Table 10
Channel Allocation
E-DPCCH (I, SFE-DPCCH, 1)
E-DPDCH1, E-DPDCH2, (Q, SF, SF/4+SF/2), (I, 4, 2)
E-DPDCH3 (Q, 4, 2)
Here, 8, 16, 32, 64, 128 and 256 are available for the SFE-DPCCH for the E-
DPCCH, and 4, 8, 16, 32, 64, 128, 256 and 512 are available for the SFE-DPDCH
for
the E-DPDCHs.
In this case, if a maximum of 3 E-DPDCH channels can be transmitted
and SF=4 is used, an E-DPDCH1 is transmitted on a Q channel using an OVSF
code (4, 3). An E-DPDCH2 is transmitted on an I channel using an OVSF code (4,
2), and an E-DPDCH3 is transmitted on the Q channel using an OVSF code (4, 2).
6. A Maximum of 3 DPDCHs being Transmittable and HS-DPCCH being
Transmitted
A method of allocating I/Q channels and OVSF codes for a DPCCH,
DPDCHs and an HS-DPCCH according to the current standard is illustrated in
Table 11.
Table 11
Channel Allocation
DPCCH (Q, 256, 0)
DPDCH1, DPDCH2, (I, SF, SF/4), (Q, 4, 1)
DPDCH3 (I, 4, 3)
HS-DPCCH (Q, 256, 32)
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A method of allocating I/Q channels and OVSF codes for an E-DPCCH
and E-DPDCHs in the present invention considering compatibility with the
current standard of Table 11 is illustrated in Table 12.
Table 12
Channel Allocation
E-DPCCH (I,. SFE-Dpccll, 1)
E-DPDCH1, E-DPDCH2, (Q, SF, SF/4+SF/2), (I, 4, 2)
E-DPDCH3 (Q, 4, 2)
Here, 8, 16, 32, 64, 128 and 256 are available for the SFE-DPCCH for the E-
DPCCH, and 4, 8, 16, 32, 64, 128, 256 and 512 are available for the SFE-DPDCH
for
the E-DPDCHs.
In this case, if a maximum of 3 E-DPDCH channels can be transmitted
and SF=4 is used, an E-DPDCH1 is transmitted on a Q channel using an OVSF
code (4, 3). An E-DPDCH2 is transmitted on an I channel using an OVSF code (4,
2), and an E-DPDCH3 is transmitted on the Q channel using an OVSF code (4, 2).
7. A Maximum of 4 DPDCHs being Transmittable and HS-DPCCH being
not Transmitted
A method of allocating I/Q channels and OVSF codes for a DPCCH and
DPDCHs according to the current standard is illustrated in Table 13.
Table 13
Channel Allocation
DPCCH (Q, 256, 0)
DPDCH1, DPDCH2, (I, SF, SF/4), (Q, 4, 1)
DPDCH3, DPDCH4 (I, 4, 3), (Q, 4, 3)
A method of allocating I/Q channels and OVSF codes for an E-DPCCH
and E-DPDCHs in the present invention considering compatibility with the
current standard of Table 13 is illustrated in Table 14.
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Table 14
Channel Allocation
E-DPCCH (I, SFE_DpccH, 1)
E-DPDCH1, E-DPDCH2 (I, SF, SF/2), (Q, 4,2)
Here, 8, 16, 32, 64, 128 and 256 are available for the SFE-DPCCH for the E-
DPCCH, and 4, 8, 16, 32, 64, 128, 256 and 512 are available for the SFE-DPDCH
for
the E-DPDCHs.
In this case, if a maximum of 2 E-DPDCH channels can be transmitted
and SF=4 is used, an E-DPDCH1 is transmitted on an I channel using an OVSF
code (4, 2) and an E-DPDCH2 is transmitted on a Q channel using an OVSF code
(4,2).
8. A Maximum of 4 DPDCHs being Transmittable and HS-DPCCH being
Transmitted
A method of allocating I/Q channels and OVSF codes for a DPCCH and
DPDCHs according to the current standard is illustrated in Table 15.
Table 15
Channel Allocation
DPCCH (Q, 256, 0)
DPDCH1, DPDCH2, (I, SF, SF/4), (Q, 4, 1)
DPDCH3, DPDCH4 (I, 4, 3), (Q, 4, 3)
HS-DPCCH (I, 256, 1)
A method of allocating I/Q channels and OVSF codes for an E-DPCCH
and E-DPDCHs in the present invention considering compatibility with the
current standard of Table 15 is illustrated in Table 16.
Table 16
Channel Allocation
E-DPCCH (Q, SFE-DPCCH, SFE-DPCCH/8)
E-DPDCH1, E-DPDCH2 (I, SF, SF/2), (Q, 4,2)
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Here, 64, 128 and 256 are available for the SFE_DpccH for the E-DPCCH,
and 4, 8, 16, 32, 64, 128, 256 and 512 are available for the SFE-DPDCH for the
E-
DPDCHs.
In this case, if a maximum of 2 E-DPDCH channels can be transmitted
and SF=4 is used, an E-DPDCH1 is transmitted on an I channel using an OVSF
code (4, 2) and an E-DPDCH2 is transmitted on a Q channel using an OVSF code
(4,2).
9. A Maximum of 5 DPDCHs being Transmittable and HS-DPCCH being
not Transmitted
A method of allocating I/Q channels and OVSF codes for a DPCCH and
DPDCHs according to the current standard is illustrated in Table 17.
Table 17
Channel Allocation
= DPCCH (Q, 256, 0)
DPDCH1, DPDCH2, (I, SF, SF/4), (Q, 4, 1)
DPDCH3, DPDCH4, (I, 4, 3), (Q, 4, 3)
DPDCH5 (I, 4, 2)
A method of allocating I/Q channels and OVSF codes for an E-DPCCH
and E-DPDCHs in the present invention considering compatibility with the
current standard of Table 17 is illustrated in Table 18.
Table 18
Channel Allocation
E-DPCCH (I, SFE-DPCCH, 1)
E-DPDCH1 (Q, SF, SF/2)
Here, 8, 16, 32, 64, 128 and 256 are available for the SFE-DPCCH for the E-
DPCCH, and 8, 16, 32, 64, 128, 256 and 512 are available for the SFE-DPDCH for
the E-DPDCHs. A maximum of only one E-DPDCH can be transmitted. An E-
DPDCH1 is transmitted on a Q channel using an OVSF code (4, 2).
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10. A Maximum of 5 DPDCHs being Transmittable and HS-DPCCH
being Transmitted
A method of allocating I/Q channels and OVSF codes for a DPCCH and
DPDCHs according to the current standard is illustrated in Table 19.
Table 19
Channel Allocation
DPCCH (Q, 256, 0)
DPDCH I, DPDCH2, (I, SF, SF/4), (Q, 4, 1)
DPDCH3, DPDCH4, (I, 4, 3), (Q, 4, 3)
DPDCH5 (I, 4, 2)
HS-DPCCH (Q, 256, 32)
A method of allocating I/Q channels and OVSF codes for an E-DPCCH
and E-DPDCHs in the present invention considering compatibility with the
current standard of Table 19 is illustrated in Table 20.
Table 20
Channel Allocation
E-DPCCH (I, SFE-DPCCH, 1)
E-DPDCH1, E-DPDCH2 (Q, SF, SF/2)
Here, 8, 16, 32, 64, 128 and 256 are available for the SFE-DPCCH for the E-
DPCCH, and a maximum of only one E-DPDCH can be transmitted. An E-
DPDCHI is transmitted on a Q channel using an OVSF code (4, 2).
Seventh Embodiment
Compared with the sixth embodiment, a seventh embodiment presents an
allocation rule which is similar in packet back-off required in an RF power
amplifier but simpler in implementation. A method of allocating I/Q channels
and
OVSF codes for an E-DPCCH and E-DPDCHs is determined based on the
maximum number of transmittable DPDCHs and transmission/non-transmission
of an HS-DPCCH, and a basic rule thereof is as follows:
E-DPCCH: If the maximum number of transmittable DPDCHs is 2 or 4
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and an HS-DPCCH is allocated (I, 256, 1), it uses (Q, SFE-DPCCH, SFE-DPCCH/8)
and
in other cases, it uses (I, SFE-Dpcm, 1).
E-DPDCH: When several DPDCH channels are transmitted, the
DPDCHs use OVSF codes in order of (I, 4, 1), (Q, 4, 1), (I, 4, 3), (Q, 4, 3),
(I, 4,
2) and (Q, 4, 2) according to a data rate. Therefore, the E-DPDCHs
additionally
use the remaining codes except the codes set for DPDCH transmission among the
six codes in the arranged order according to a EUDCH packet data rate.
In a stand-alone case where only EUDCH is transmitted, HSDPA uses an
OVSF code (256, 1) on an I channel, and in a case where a DPDCH is set up,
HSDPA follows the Re1-5 standard.
It is most preferable to allocate I/Q channels and OVSF codes for the E-
DPCCH and E-DPDCHs in the foregoing manner in terms of a PAPR.
1. HS-DPCCH being not Set Up and EUDCH Stand-Alone
An E-DPCCH always uses (I, SFE-DPCCH, 1). Here, 8, 16, 32, 64, 128 and
256 are available for the SFE-DPCCH.
As illustrated in Table 21, the E-DPDCHs are allocated I/Q channels and
OVSF codes according to the maximum number of transmittable DPDCHs.
Table 21 ,
Max No of Max No of
Transmittable Transmittable E-DPDCH Allocation Order
DPDCHs E-DPDCHs
0
(I, SF, SF/4), (Q, 4, 1), (I, 4, 3), (Q, 4, 3), (I,
6
4, 2), (Q, 4, 2)
1 5 (Q, SF, SF/4), (I, 4, 3), (Q, 4, 3), (I,
4,2), (Q,
:4,2)
2
(I, SF, SF/2+SF/4), (Q, 4, 3), (1, 4, 2), (Q, 4,
4
2)
3 3 (Q, SF, SF/2+SF/4), (I, 4, 2) (Q, 4,2)
4 2 (I, SF, SF/2), (Q, 4, 2)
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1 (Q, SF, SF/2)
In Table 21,4, 8, 16, 32, 64, 128, 256 and 512 are available for the SF. In
Table 21, if the maximum number of transmittable DPDCHs is 0, E-DPDCHs
transmitting EUDCH data can use a maximum of 6 codes.
5
For example, when all of the six channels are used according to the
EUDCH data rate, an E-DPDCH1 is transmitted on an I channel using an OVSF
code (4, 1), and an E-DPDCH2 is transmitted on a Q channel using an OVSF
code (4, 1). An E-DPDCH3 is transmitted on the I channel using an OVSF code
(4, 3), and an E-DPDCH4 is transmitted on the Q channel using an OVSF code (4,
3). An E-DPDCH5 is transmitted on the I channel using an OVSF code (4, 2), and
an E-DPDCH6 is transmitted on the Q channel using an OVSF code (4, 2).
As another example, if the maximum number of transmittable DPDCHs
is 4 in Table 21, E-DPDCHs for transmitting EUDCH data can use a maximum of
2 codes. For the E-DPDCHs, an E-DPDCH1 is transmitted on an I channel using
an OVSF code (SF, SF/2), and an additionally allocated E-DPDCH2 is
transmitted on a Q channel using an OVSF code (4, 2).
2. A Maximum of 1 DPDCH being Transmittable and HS-DPCCH being
Allocated (0, 256, 64)
An E-DPCCH always uses (I, SFE-DPCCI-1) 1). Here, 8, 16, 32, 64, 128 and
256 are available for the SFE-DPCCH-
The E-DPDCHs are sequentially allocated four OVSF codes (I, SF,
SF/2+SF/4), (Q, 4, 3), (1, 4, 2) and (Q, 4, 2) according to a EUDCH data rate.
Here, 4, 8, 16, 32, 64, 128, 256 and 512 are available for the SF. Because the
HS-
DPCCH is allocated (Q, 256, 64) on the Q channel, the OVSF code (4, 1) can be
hardly used for an E-DPDCH.
3. A Maximum of 2 DPDCHs being Transmittable and HS-DPCCH being
Set Up
As illustrated in Table 22, an E-DPCCH is allocated I/Q channels and
OVSF codes according to the maximum number of transmittable DPDCHs.
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Table 22
Max No of Transmittable DPDCHs E-DPCCH Allocation
1, 3, 5 (I, SFE-DPCCH, 1)
2, 4 (Q, SFE-mccH, SFE-DpccH/8)
In this case, if the maximum number of transmittable DPDCHs is 2 or 4
and an HS-DPCCH is allocated (I, 256, 1), an E-DPCCH uses (Q, SFE_DpccH, SFE_
nrcci4/8). Here, 64, 128 and 256 are available for the SFE-DPCCH-
However, the E-DPDCHs are allocated I/Q channels and OVSF codes as
illustrated in Table 21 according to the maximum number of transmittable
DPDCHs.
Eighth Embodiment
An eighth embodiment has a basic principle of first allocating an E-
DPDCH to a Q channel for an OVSF code having the same index, and
additionally allocating an E-DPDCH to an I channel. In this case, codes for
the E-
DPDCHs are determined according to the maximum number of transmittable
DPDCHs and transmission/non-transmission of an HS-DPCCH.
That is, according to the eighth embodiment, DPDCHs are first allocated
to an I channel and E-DPDCHs are first allocated to a Q channel, so that the
numbers of DPDCHs and E-DPDCHs transmitted on the I/Q channels can be
equal to each other. In order words, when an HS-DPCCH is transmitted on the Q
channel using an OVSF code (256, 64) or the number of the DPDCHs is smaller
than the maximum number of transmittable DPDCHs, the eighth embodiment can
prevent an excessive increase in PAPR due to the preponderance of DPDCHs and
E-DPDCHs over the I channel.
However, when the foregoing OVSF code and I/Q channel allocation rule
for E-DPDCHs is used, compared with a DPCCH using an OVSF code (256, 0)
on a Q channel, an E-DPDCH is transmitted on an I channel using (SF, 1),
thereby minimizing an increase in PAPR. Here, 4, 8, 16, 32, 64 and 128 are
available for the SF. In a stand-alone case, HSDPA uses an OVSF code (256, 1)
on an I channel, and in a case where a DPDCH is set up, HSDPA follows the Rel-
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standard. It is most preferable to allocate OVSF codes in the foregoing manner
in terms of a PAPR.
I. HS-DPCCH being not Set Up and EUDCH Stand-Alone
5 E-DPDCHs are allocated I/Q channels and OVSF codes as illustrated
in
Table 23 according to the maximum number of transmittable DPDCHs.
Table 23
Max No of Max No of
Transmittable Transmittable E-DPDCH Allocation Order
DPDCHs E-DPDCHs
0 6 (Q, SF, SF/4), (I, 4, 1), (Q, 4, 3), (I,
4, 3), (Q,
4, 2), (I, 4, 2)
1
(Q, SF, SF/4), (Q, 4, 3), (I, 4, 3), (Q, 4, 2), (I,
5
4,2)
2
(Q, SF, SF/2+SF/4), (I, 4, 3), (Q, 4, 2), (I, 4,
4
2)
3 3 (Q, SF, SF/2+SF/4), (Q, 4, 2) (I, 4,
2)
4 2 (Q, SF, SF/2), (I, 4, 2)
5 1 (I, SF, SF/2)
In Table 23, 4, 8, 16, 32, 64, 128, 256 and 512 are available for the SF. In
Table 23, if the maximum number of transmittable DPDCHs is 0, a maximum of
6 E-DPDCH channels can be transmitted. In this case, OVSF codes are used in
order of (Q, SF, SF/4), (I, 4, 1), (Q, 4, 3), (I, 4, 3), (Q, 4, 2) and (I, 4,
2) according
to the number of E-DPDCH channels being transmitted.
However, if the maximum number of transmittable DPDCHs is 1, a
maximum of 5 codes can be used for E-DPDCH channels transmitting EUDCH
data, so that a maximum of 5 E-DPDCH channels can be transmitted. In this
case,
OVSF codes are used in order of (Q, SF, SF/4), (Q, 4, 3), (I, 4, 3), (Q, 4, 2)
and (I,
4, 2) according to the number of E-DPDCH channels being transmitted.
As another example, if the maximum number of transmittable DPDCHs
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is 4 in Table 23, a maximum of 2 codes can be used for E-DPDCHs. In this case,
when only one E-DPDCH is transmitted, the E-DPDCH is transmitted on a Q
channel using an OVSF code (SF, SF/2), and an E-DPDCH additionally allocated
when necessary is transmitted on an I channel using an OVSF code (4, 2).
2. A Maximum of 1 DPDCH being Transmittable and HS-DPCCH being
Allocated (Q, 256, 64)
E-DPDCHs are sequentially allocated four OVSF codes (Q, SF,
SF/2+SF/4), (I, 4, 3), (Q, 4, 2) and (I, 4, 2) according to a EUDCH data rate.
Here,
4,8, 16, 32, 64, 128, 256 and 512 are available for the SF.
For example, when only one E-DPDCH is transmitted, the E-DPDCH is
transmitted on a Q channel using an OVSF code (SF, SF/2+SF/4). This is to
prevent an excessive increase in PAPR due to the preponderance of physical
data
channels over one of the I and Q channels. Therefore, DPDCHs are transmitted
on the I channel and E-DPDCHs are transmitted on the Q channel, so that the
number of physical data channels transmitted on the I channel is equal to the
number of physical data channels transmitted on the Q channel, thereby
preventing an increase in PAPR.
3. A Maximum of 2 DPDCHs being Transmittable and HS-DPCCH being
Set Up
The same code allocation rule as that illustrated in Table 23 is used.
Ninth Embodiment
When several E-DPDCH physical channels are transmitted, SF=2 OVSF
codes are used for E-DPDCHs exceptionally only in the following case in order
to
further reduce a PAPR.
For example, when (I, 4, 3) and (I, 4, 2) are simultaneously allocated to
E-DPDCHs for multicode transmission on the E-DPDCHs, the E-DPDCHs are
transmitted using (I, 2, 1) instead of the foregoing two codes. That is, for
the case
where E-DPDCHs are transmitted on the I channel using both of the OVSF codes
(4, 3) and (4, 2), the E-DPDCHs are transmitted on the I channel using the
OVSF
code (2, 1).
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Likewise, for the case where OVSF codes (4, 3) and (4, 2) are
simultaneously allocated to E-DPDCHs on a Q channel, the E-DPDCHs are
transmitted on the Q channel using an OVSF code (2, 1). That is, the E-DPDCHs
are transmitted using (Q, 2, 1).
The following tenth embodiment proposes a method of additionally using
possible codes generated from an OVSF code (4, 1), including a Q channel OVSF
code (256, 64) used by an HS-DPCCH channel, for E-DPDCHs. In addition, the
tenth embodiment proposes a method of additionally using codes allocated to
DPDCHs, for E-DPDCHs.
Tenth Embodiment
An OVSF code (Q, 256, 64) used for an HS-DPCCH is used for an
additional E-DPDCH. That is, the tenth embodiment allows an HS-DPCCH to use
an OVSF code (256, 32) on a Q channel, thereby guaranteeing a EUDCH data
rate. In this embodiment, OVSF code and I/Q channel allocation methods for E-
DPDCHs are summarized as follows.
1. Two or Less E-DPDCH Channels being Transmitted
The methods proposed in the first to fifth embodiments are used.
2. Three E-DPDCH Channels being Transmitted
An E-DPDCH1 and an E-DPDCH2 are allocated to I and Q channels,
respectively, using an OVSF code (2, 1).
An E-DPDCH3 is allocated to the Q channel using an OVSF code (4, 1).
In this case, data transmitted over the E-DPDCH3 undergoes QPSK modulation.
In addition, methods of using OVSF codes allocated to DPDCHs, for E-
DPDCHs, are as follows.
1. Three or Less E-DPDCH Channels being Transmitted
The methods proposed in the sixth to ninth embodiments are used.
2. Four or Less E-DPDCH Channels being Transmitted
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When no DPDCH is transmitted, a fourth E-DPDCH is transmitted on an I
channel using an OVSF code (4, I).
As described above, the present invention proposes an OVSF code and I/Q
channel allocation method optimized for E-DPDCHs and an E-DPCCH for EUDCH
service, while maintaining backward compatibility with DPDCHs and a DPCCH
which
are uplink physical channels, in a method for allocating OVSF codes and I/Q
channels to
uplink physical channels. In addition, the present invention proposes an HS-
DPCCH
channel and an OVSF code which are different from those defined in the
existing Re1-5
standard in order to increase a maximum EUDCH data rate, and an OVSF code and
I/Q
channel allocation method optimized for E-DPDCHs and an E-DPCCH for the EUDCH
service for the foregoing case.
Therefore, the present invention can minimize a PARP increase during packet
data transmission for the EUDCH service and minimize a transmission error of
EUDCH
packet data, thereby contributing to an increase in EUDCH service capacity.
While the invention has been shown and described with reference to a certain
preferred embodiment thereof, it will be understood by those skilled in the
art that
various changes in form and details may be made therein without departing from
the
scope of the invention as defined by the appended claims.
