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TSG-C
TITLE:
Problem in Access Barring Support
SOURCE:
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Tony Lee
[email protected]
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ABSTRACT:
This contribution provides fixes to the problems found in section 4.6
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RECOMMENDATION:
Discuss and adopt for C.S0097-0 v3.0 or C.S0097-A
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which incorporates this contribution.
This document has been prepared by VIA Telecom to assist the development of specifications by 3GPP2. It is
proposed to the Committee as a basis for discussion and is not to be construed as a binding proposal on VIA Telecom.
VIA Telecom specifically reserves the right to amend or modify the material contained herein and to any intellectual
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Problem Description
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In section 4.6, 1x CSFB Access Barring Support, it requires the mobile to use the persistence test
based on C.S0003 and the random number generator based on C.S0005.
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1xCSFB Access Barring Support
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E-UTRAN provides the access class barring parameters (ac-Barring) in the SIB8 Error!
Reference source not found.. When the ac-Barring values are set, the mobile station shall
perform a persistence test only one time using a random value locally generated by the mobile
station when the mobile station makes a voice call origination, SMS origination or registration.
The persistence test procedure shall be based on Error! Reference source not found.. The
mobile station shall generate a random number RP, 0 < RP < 1, using the technique described in
the "Pseudorandom Number Generator" Error! Reference source not found.. The persistence
test passes when RP is less than the value of P (P is computed as detailed in Error! Reference
source not found. assuming the ac-Barring received in SIB-8 as PSIST values). If the persistence
test passes, the mobile station may trigger a voice call origination, SMS origination or
registration. If the persistence test fails, the mobile stations behavior is out of scope of this
specification.
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Extract of SIB 8 in TS 36.331
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Problems:
AC-BarringConfig1XRTT-r9 ::=
ac-Barring0to9-r9
ac-Barring10-r9
ac-Barring11-r9
ac-Barring12-r9
ac-Barring13-r9
ac-Barring14-r9
ac-Barring15-r9
ac-BarringMsg-r9
ac-BarringReg-r9
ac-BarringEmg-r9
SEQUENCE {
INTEGER
INTEGER
INTEGER
INTEGER
INTEGER
INTEGER
INTEGER
INTEGER
INTEGER
INTEGER
(0..63),
(0..7),
(0..7),
(0..7),
(0..7),
(0..7),
(0..7),
(0..7),
(0..7),
(0..7)
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1. In CSFB, there is no MAC layer as defined in C.S0003.
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2. According to C.S0003, the access procedure that employs the persistence test also requires
a delay value of R-ACH slot. It is not clear whether C.S0097 should use a delay of R-ACH
slot or some other delay values.
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3. The random number generator as specified in C.S0005 requires the System Time from the
Sync Channel Message to use as a seed. In a tunneled environment, there is no Sync
Channel Message and thus there is a need to use another source to supplement the seed.
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4. No procedure for mobile when there is no ac-Barring information.
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Proposed Solution:
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Solution to problem:
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1. Remove reference to C.S0003
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2. Define a delay value in C.S0097. Either fixed or through CDMA2000Parameters. An
alternative way is not reference the persistence procedure.
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3. Remove reference to the random number generator as defined in C.S0005. Add text to let
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4. Add a paragraph for the case when ac-Barring information are not available.
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mobile to use any random number generator that can generate a uniformly distributed
random number between 0 and 1.
Proposed Text
E-UTRAN provides the access class barring parameters (ac-Barring) in SIB8 Error! Reference
source not found..
When the ac-Barring values are set, the mobile station shall execute the following procedure
before a voice call origination, SMS origination, or registration:
1. Generate a number N based on the procedure as defined in [11] for the persistence
variable P, where the PSIST values used in [11] are substitute by the ac-Barring values
2. Generate a random number R, where 0 < R < 1, by using a uniformly distributed random
number generator
3. If R is less than N, the mobile station shall proceed with the access requested
4. Otherwise, the mobile shall refrain from access the E-UTRAN system for an
implementation amount of time
When the ac-Barring values are not set, the mobile station shall set N=1 when performing the
above procedure.
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