Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
2001-03-16
2004-08-17
Tran, Cong Van (Department: 2683)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S450000, C455S504000, C370S329000, C370S331000, C370S341000
Reexamination Certificate
active
06778835
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a channel allocation technique of a third generation partnership project (3GPP), and more particularly to a method for allocating a physical channel of a mobile communication system that is capable of effectively allocating a physical channel of a RACH (Random Access Channel) and a CPCH (Common Packet Channel) having an up-link scrambling code, and a communication using the same.
2. Description of the Background Art
Generally, in the 3GPP system, the RACH and the CPCH, the up-link channels that a user terminal or a user equipment (UE) uses to transmit a data to a base station, uses 16 signatures and an OVSP (Orthogonal Variable Spreading Factor) code for allocating a physical channel.
That is, the terminal uses one of 16 signatures (Ap#s, #s=0, 1, 2, . . . , 15) to generate a preamble signature (C
sig,s
), generages a random access preamble code (C
pre,n,s
) by using the generated preamble signature (C
sig,s
) and a specific physical RACH (PRACH) preamble scrambling code (S
r-pre,n
) assigned per cell, carries the generated random access preamble code (C
pre,n,s
) on an access preamble (AP) and transmits it to base station.
The random access preamble code (C
pre,n,s
) is the sequence having a complex number value as shown in the below equation (1):
C
pre
,
n
,
s
(
k
)
=
S
r
-
pre
,
n
(
k
)
×
C
sig
,
s
(
k
)
×
ⅇ
j
(
π
4
+
π
2
k
)
(
1
)
wherein, ‘k’ indicates a transmitted chip and is an integer of 0, 1, 2, . . . , 4096. Particularly, if ‘k’ is ‘0’, it signifies the chip which is first transmitted for a corresponding time, ‘s’ is a signature number and an integer of 0, 1, 2, . . . ,15.
First, the physical channel allocation method of the RACH will now be explained with reference to the accompanying drawings.
FIG. 1
is a diagram showing a construction of a code tree for allocating a physical channel of the RACH in accordance with a conventional art.
As shown in the drawing, as a spreading factor (SF) is increased, an OVSP code is accordingly increased. For example, as for the 16 signatures (AP#0-AP#15), if the spreading factor (SF) is 16, each signature and the OVSF (Orthogonal Variable Spreading Factor) code is in a one-to-one ratio. The AP#0-AP#15 indicates the types of signature carried on the AP and transmitted by the terminal.
FIG. 2
is a diagram showing a construction of the OVSF code tree in accordance with the conventional art, which corresponds to the RACH physical channel allocation code tree of FIG.
1
. That is, each of the tree of
FIG. 1
is coded to the OVSF code (C
ch,SF,K
), having each value.
In the OVSF code (C ch,SF,k), the SF indicates a spreading factor, and ‘k’ indicates the order of the OVSF code. For example, in case of Cch
2,1
, its SF is 2 and ‘k’ is ‘1’, indicating that it is the second code of the OVSF code.
C
ch,SF,k
has a code value allocated to each node in the OVSF code tree, of which ‘k’ also signifies the number of the node. In this case, a code value allocated to the node is obtained by the following equations (2) and (3):
C
ch
,
1
,
0
=
1
(
2
)
[
C
ch
,
2
,
0
C
ch
,
2
,
1
]
=
[
C
ch
,
1
,
0
C
ch
,
1
,
0
C
ch
,
1
,
0
-
C
ch
,
1
,
0
]
=
[
1
1
1
-
1
]
(
3
)
[
C
ch
,
2
(
n
+
1
)
,
0
C
ch
,
2
(
n
+
1
)
,
1
C
ch
,
2
(
n
+
1
)
,
2
C
ch
,
2
(
n
+
1
)
,
3
…
C
ch
,
2
(
n
+
1
)
,
2
(
n
+
1
)
-
2
C
ch
,
2
(
n
+
1
)
,
2
(
n
+
1
)
-
1
]
=
[
C
ch
,
2
n
,
0
C
ch
,
2
n
,
0
C
ch
,
2
n
,
0
-
C
ch
,
1
,
0
C
ch
,
2
n
,
1
C
ch
,
2
n
,
1
C
ch
,
2
n
,
1
-
C
ch
,
2
n
,
1
…
C
ch
,
2
n
,
2
n
-
1
C
ch
,
2
n
,
2
n
-
1
C
ch
,
2
n
,
2
n
-
1
-
C
ch
,
2
n
,
2
n
-
1
]
(
4
)
The OVSF code is a channelization code, which uses two types of codes for a data portion and a control portion of a message to be transmitted. The method for determining the two types of codes will now be explained.
FIG. 3
is a diagram of an OVSF code tree for explaining the method for allocating the OVSF code for a message of the PRACH (Physical Random Access Channel) in accordance with the conventional art.
For the data portion and the control portion of a message to be transmitted, as shown in
FIG. 3
, the OVSF code is allocated according to a particular rule (or a formula) along the tree at the right side from the node corresponding to a signature of the terminal itself.
For example, reference to the code tree of
FIG. 1
, if the SF of the signature is 16, the SF of the OVSF code for the data portion of the message is 32~256, the SF of the OVSF code for the control portion is 256 constantly. Accordingly, the PRACHs used by each terminal is identified by the OVSF code. In this respect, the every PRACH uses the same PRACH message part scrambling code.
FIG. 4
is a diagram showing a communication procedure between a terminal and a base station through the RACH physical channel as allocated in accordance with the conventional art.
When the terminal carries a specific signature on the AP and transmits it through the physical channel of the RACH allocated in the method of
FIG. 1
, the base station transmits an acquisition indicator (AI) through the AICH (Acquisition Indicator Channel).
Then, the terminal determines an OVSF code which is available to itself from the node corresponding to an acquired signature and transmits a message (MSG) to the base station by using the available OVSF code and a specific PRACH message part scrambling code which is allocated by one for one cell. The message (MSG) includes the data part and the control part.
FIG. 5
is a diagram showing a structure of an AICH in use for the 3GPP system in accordance with the conventional art.
One AICH includes 15 access slots (AS; AS#0, AS#1, . . . , AS#14), and has the length of about 20 ms. One AS has the length of 40 bit.
The AS includes a 32 bit (a0, a1, a2, . . . , a31) AI (Acquisition Indicator) part and a 8 bit (a32, a33, . . . , a39) part which is not transmitted.
The 32 bit AI is allocated to inform whether a signature previously transmitted by the terminal can be available to use. Thus, as the terminal interprets the bit of the AI part, it is judged whether a signature used in the access preamble can be available for use.
FIG. 6
illustrates a table indicating the number of the AS corresponding to the RACH sub-channel in used for the 3GPP system.
As shown in the drawing, the 3GPP system includes 12 RACH sub-channel for use, of which each sub-channel includes available access slots according to the current system frame number (SFN). The SFN is information given to the terminal by a P-CCPCH (Primary Common Control Physical Channel) and is used for various timings.
FIG. 7
illustrates a construction of a system for spreading the message part of the PRACH in the terminal in accordance with the conventional art.
The control part of the PRACH message has a real value and is diffused by a channelization code (Cc). The data part of the PRACH message has a real value and is diffused by a channelization code (Cd).
The two types of diffused signals are respectively multiplied by gain factors (Ad, Ac) to generate signals having a weight, which are outputted to an ‘I ’ and a ‘Q’ branches.
Thereafter, the signal outputted to the ‘I’ branch and the signal outputted to the ‘Q’ branch are multiplied by a complex factor (j) to generate complex signals, which are added to be converted to a complex signal stream (I+jQ).
The complex signal stream is a complex scrambling code, which is multiplied by the PRACH message part scrambling code (S
r-msg,n
) so as to to be scrambled. The S
r-msgn
and the PRACH preamble scrambling code S
r-msg,n
used in the AP are in a one-to-one ratio.
Likewise in the RACH physical channel allocation method, the physical channel allocation method of the CPCH of the conventional art will now be described with reference to the accompanying drawings.
In the b
3
GPP system of the conventional art, the terminal generates a PCPCH access preamble code C
c-acc,n,s
,
Kang Young Hwan
Seol Jee Woong
You Cheol Woo
Lee Hong Degerman Kang & Schmadeka
LG Electronics Inc.
Tran Cong Van
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