Microsoft PowerPoint WCDMA UE Behaviors in Idle Mode RAN6 www huawei com Copyright © 2008 Huawei Technologies Co , Ltd All rights reserved WCDMA UE Behaviors in Idle Mode 1 Page1Copyright © 2008 Huawe[.]
WCDMA UE Behaviors in Idle Mode www.huawei.com Copyright © 2008 Huawei Technologies Co., Ltd All rights reserved Foreword z UE behaviors in idle mode include : PLMN selection System information reception Cell selection and reselection Location registration Paging procedure Access procedure Copyright © 2008 Huawei Technologies Co., Ltd All rights reserved z Page1 PLMN selection Used to ensure that the PLMN selected by the UE properly provides services z Cell selection and reselection Used to ensure that the UE finds a suitable cell to camp on z Location registration Used for the network to trace the current status of the UE and to ensure that the UE is camped on the network when the UE does not perform any operation for a long period z System information reception The network broadcasts the network information to a UE which camps on the cell to control the behaviors of the UE z Paging Used for the network to send paging messages to a UE which is in idle mode, CELL_PCH state, or URA_PCH state z Access From the view of access stratum, access is the procedure UE shift from idle mode to connected mode Contents PLMN Selection System Information Reception Cell Selection and Reselection Location Registration Paging Procedure Access Procedure Copyright © 2008 Huawei Technologies Co., Ltd All rights reserved Page2 Contents PLMN Selection System Information Reception Cell Selection and Reselection Location Registration Paging Procedure Access Procedure Copyright © 2008 Huawei Technologies Co., Ltd All rights reserved Page3 Cell Search z UE does not have UTRAN carrier information In order to find a suitable cell to stay, UE will scan all the frequencies in UTRAN In each carrier, UE just need to find a cell with best signal z UE has UTRAN carrier information UE will try whether the original cell is suitable to stay If not, UE still need to scan all the frequencies about UTRAN in order to find a suitable cell in PLMN Copyright © 2008 Huawei Technologies Co., Ltd All rights reserved Page4 z Typical scenario of first occasion is the first time a new UE is put into use z The second occasion is very common Cell Search Slot synchronization Frame synchronization and code-group identification Primary Scrambling code identification Copyright © 2008 Huawei Technologies Co., Ltd All rights reserved z Page5 Step 1: Slot synchronization During the first step of the cell search procedure the UE uses the primary synchronisation code (PSC) to acquire slot synchronisation to a cell z Step 2: Frame synchronization and code-group identification During the second step of the cell search procedure, the UE uses the secondary synchronisation code (SSC) to find frame synchronisation and identify the code group of the cell found in the first step z Step 3: Primary Scrambling code identification: During the last step of the cell search procedure, the UE determines the exact primary scrambling code used by the found cell The primary scrambling code is typically identified through symbol-by-symbol correlation over the CPICH with all codes within the code group identified in the second step z If the UE has received information about which scrambling codes to search for, steps and above can be simplified PLMN Selection z UE shall maintain a list of allowed PLMN types In the PLMN list, the UE arranges available PLMNs by priorities When selecting a PLMN, it searches the PLMNs from the high priority to the low z The UE selects a PLMN from HPLMNs or VPLMNs Copyright © 2008 Huawei Technologies Co., Ltd All rights reserved z z Page6 UE can get the system information from PCCPCH, and the PLMN information is transmitted in MIB of PCCPCH After getting the MIB, UE can judge weather the current PLMN is the right one If so, UE will get the SIB scheduling information from the MIB; if not, UE will search another carrier, this procedure again PLMN Selection (Cont.) z PLMN Selection in HPLMNs Automatic PLMN Selection Mode The UE selects an available and suitable PLMN from the whole band according to the priority order Manual PLMN Selection Mode The order of manual selection is the same as that of automatic selection Copyright © 2008 Huawei Technologies Co., Ltd All rights reserved z Page7 The priority order for automatic PLMN selection mode Order PLMN type Remark HPLMNs Home PLMNs PLMNs contained in the "User Controlled PLMN Selector with Access Technology" data field in the SIM excluding the previously selected PLMN The PLMNs are arranged in priority order PLMNs contained in the "Operator Controlled PLMN Selector with Access Technology" data field in the SIM excluding the previously selected PLMN The PLMNs are arranged in priority order Other PLMN/access technology combinations with the high quality of received signals excluding the previously selected PLMN The PLMNs are arranged in random order Other PLMN/access technology combinations excluding the previously selected PLMN The PLMNs are arranged in descending order of signal quality Previously selected PLMN The PLMN selected by the UE before automatic PLMN selection PLMN Selection (Cont.) z PLMN Selection in VPLMNs If a UE is in a VPLMN, it scans the “user controlled PLMN selector” field or the “operator controlled PLMN selector” field in the PLMN list to find the HPLMN or the PLMN with higher priority according to the requirement of the automatic PLMN selection mode Copyright © 2008 Huawei Technologies Co., Ltd All rights reserved z z z Page8 A value of T minutes may be stored in the SIM T is either in the range from minutes to hours in 6-minute steps or it indicates that no periodic attempts shall be made If no value is stored in the SIM, a default value of 60 minutes is used After the UE is switched on, a period of at least minutes and at most T minutes shall elapse before the first attempt is made The UE shall make an attempt if the UE is on the VPLMN at time T after the last attempt Contents PLMN Selection System Information Reception Cell Selection and Reselection Location Registration Paging Procedure Access Procedure Copyright © 2008 Huawei Technologies Co., Ltd All rights reserved Page9 10 Over Load Control z Over Load triggering Copyright © 2009 Huawei Technologies Co., Ltd All rights reserved If the current UL/DL load of an R99 cell is not lower than the UL/DL OLC Trigger threshold for some hysteresis (defined by the DL State Trans Hysteresis threshold in DL; not configurable in UL), the cell works in overload congestion state and the related overload handling action is taken If the current UL/DL load of the R99 cell is lower than the UL/DL OLC Release threshold for some hysteresis (defined by the DL State Trans Hysteresis threshold in DL; not configurable in UL), the cell comes back to the normal state The HSPA cell has the same uplink decision criterion as the R99 cell The load in the downlink, however, is the sum of load of the non-HSPA power (transmitted carrier power of all codes not used for HS-PDSCH or HS-SCCH transmission) and the GBP Key parameters z Cell LDC algorithm switch Parameter ID: NBMLDCALGOSWITCH z z UL_UU_OLC, DL_UU_OLC UL/DL OLC trigger threshold Parameter ID: UL/DLOLCTRIGTHD The default value of this parameter is 95% UL/DL OLC release threshold Parameter ID: UL/DLOLCRELTHD The default value of this parameter is 85% Copyright © 2009 Huawei Technologies Co., Ltd All rights reserved Cell LDC algorithm switch Parameter ID: NBMLDCALGOSWITCH Value range: OFF, ON Content: This parameter specifies the switch of UL/DL OLC UL_UU_OLC: UL overload control algorithm DL_UU_OLC: DL overload control algorithm Set this parameter through ADD CELLALGOSWITCH / MOD CELLALGOSWITCH UL/DL OLC trigger threshold Parameter ID: UL/DLOLCTRIGTHD Value range: to 100 % Content: If the UL load of the cell is not lower than the value of the UL OLC trigger threshold, the UL overload congestion control of the cell is activated If the DL load of the cell is not lower than the value of the DL OLC trigger threshold, the DL overload congestion control of the cell is activated Set this parameter through ADD CELLLDR / MOD CELLLDR UL/DL OLC release threshold Parameter ID: UL/DLOLCRELTHD Value range: to 100 % Content: If the UL load of the cell is lower than the value of the UL OLC release threshold, the UL overload congestion control of the cell is deactivated If the DL load of the cell is lower than the value of the DL OLC release threshold, the DL overload congestion control of the cell is deactivated Set this parameter through ADD CELLLDR / MOD CELLLDR The general OLC procedure covers the following actions: TF control of BE services, channel switching of BE services, and release of RABs The RNC takes periodical actions if overload congestion is detected When the cell is overloaded, the RNC takes one of the following actions in each period (defined by the OLC period timer length parameter, e.g.3s) until the congestion is resolved: TF control of BE service (only for DCH BE service) Switching BE services to common channel Choosing and releasing the RABs (for HSPA or DCH service) If the first action fails or the first action is completed but the cell is still in congestion, then the second action is taken Key parameters z OLC period timer length Parameter ID: OLCPERIODTIMERLEN The default value of this parameter is 3000 (ms) Copyright © 2009 Huawei Technologies Co., Ltd All rights reserved OLC period timer length Parameter ID: OLCPERIODTIMERLEN Value range: 100 to 86400000 Content: This parameter specifies the period of overload control The default value of this parameter is 3000 (ms) Set this parameter through SET LDCPERIOD OLC Action z TF Control Target user Based on RAB integrate priority The RABs with the DCH BE services Execution The RNC sends the “TF control indication” message to the MAC MAC restricts the TFC selection : TFmax(N+1) = TFmax(N) x Ratelimitcoeff Copyright © 2009 Huawei Technologies Co., Ltd All rights reserved Based on the RAB integrate priority, the OLC sorts the RABs into a descending order.The following RABs are selected: The RABs with the DCH BE services The RABs with the lowest integrate priority The number of RABs selected is DL/UL OLC fast TF restrict RAB number The RNC sends the TF control indication message to the MAC Each MAC of selected RABs will receive one TF control indication message and will restrict the TFC selection of the BE services to reduce the data rate step by step MAC restricts the TFC selection in a way like that the maximum TB number is calculated with the formula: TFmax(N+1) = TFmax(N) x Ratelimitcoeff Ratelimitcoeff is a configurable parameter (DL OLC fast TF restrict data rate restrict coefficient) If the RNC cannot find an appropriate service for the TF control or the time for performing the TF control exceed the DL OLC fast TF restrict times parameter, the action fails The OLC performs the next action If the congestion is released, the RNC sends the congestion release indication to the MAC At the same time, the rate recovery timer (whose length is defined by DL OLC fast TF restrict data rate recover timer length) is started When this timer is expired, the MAC increases the data rate step by step MAC recovers the TFC selection by calculating the maximum TB number with the formula: TFmax(N+1) = TFmax(N) x RateRecoverCoeff RateRecoverCoeff is a configurable parameter (DL TF rate recover coefficient) OLC Action z TF Control example Copyright © 2009 Huawei Technologies Co., Ltd All rights reserved Before point A, the cell is not in OLC state The downlink data transfer rate is 384 kbit/s, the corresponding TF is 12 x 336, and TFS is {12 x 336, x 336, x 336, x 336, x 336, x 336}.336 is the TB size, 320 payload + 16 MAC head At point A, the cell enters OLC state The RNC selects this RAB to fast TF restriction MAC restricts the TFC selection during time between point A and point B by calculating the maximum TB number as follows: TFmax(1) = TFmax(0) x Ratelimitcoeff = 12 x 0.68 = 8.16 Match 8.16 and the TFS Therefore, the maximum TB number is At point B, MAC performs further TFC restriction by calculating maximum TB number as follows: TFmax(2) = TFmax(1) x Ratelimitcoeff = x 0.68 = 5.44 Match 5.44 and the TFS Then, the maximum TB number is At point C and point D, similar process is followed Key parameters z z UL/DL OLC fast TF restrict RAB number Parameter ID: UL/DLOLCFTFRSTRCTRABNUM The default value of this parameter is UL/DL OLC fast TF restrict times Parameter ID: UL/DLOLCFTFRSTRCTTIMES The default value of this parameter is Copyright © 2009 Huawei Technologies Co., Ltd All rights reserved UL/DL OLC fast TF restrict RAB number Parameter ID: UL/DLOLCFTFRSTRCTRABNUM Value range: to 10 Content: These parameters specify the maximum number of RABs selected in a fast TF restriction of UL/DL OLC If the number of RABs that fulfil the criteria for TF control is smaller than the value of this parameter, then all the RABs that fulfil the criteria are selected The default value of this parameter is Set this parameter through ADD CELLOLC / MOD CELLOLC UL/DL OLC fast TF restrict times Parameter ID: UL/DLOLCFTFRSTRCTTIMES Value range: to 100 Content: These parameters specify the times of UL/DL OLC fast TF restrictions that are executed The default value of this parameter is Set this parameter through ADD CELLOLC / MOD CELLOLC Key parameters z z DL TF rate restrict coefficient Parameter ID: RateRstrctCoef The default value of this parameter is 68% DL TF rate restrict timer length Parameter ID: RateRstrctTimerLen The default value of this parameter is 3000 (ms) Copyright © 2009 Huawei Technologies Co., Ltd All rights reserved DL TF rate restrict coefficient Parameter ID: RateRstrctCoef Value range: to 99 % Content: This parameter specifies the data rate restriction coefficient in the fast TF restriction The smaller the parameter is, the more effective the TF restriction is After receiving the TF control indication, the MAC obtains the maximum TF format with the formula TFmax' = TFmax x Ratelimitcoeff The default value of this parameter is 68 % Set this parameter through ADD CELLOLC / MOD CELLOLC DL TF rate restrict timer length Parameter ID: RateRstrctTimerLen Value range: to 65535 ms Content: This parameter specifies the length of the data rate restriction timer in the fast TF restriction The smaller the value of this parameter is, the more effective the TF restriction is The default value of this parameter is 3000 ms Set this parameter through ADD CELLOLC / MOD CELLOLC Key parameters z z DL TF rate recover timer length Parameter ID: RateRecoverTimerLen The default value of this parameter is 5000 (ms) DL TF rate recover coefficient Parameter ID: RecoverCoef The default value of this parameter is 130 % Copyright © 2009 Huawei Technologies Co., Ltd All rights reserved DL TF rate recover timer length Parameter ID: RateRecoverTimerLen Value range: to 65535 ms Content: This parameter specifies the length of the data rate recovery timer The smaller the value of this parameter is, the faster the BE traffic rate increases after the congestion is resolved The default value of this parameter is 5000 ms Set this parameter through ADD CELLOLC / MOD CELLOLC DL TF rate recover coefficient Parameter ID: RecoverCoef Value range: 100 to 200 % Content: This parameter specifies the data rate recovery coefficient in the fast TF restriction The larger the parameter is, the larger the TF recover effect After receiving congestion release indication, the MAC obtains the maximum TF format with the formula TFmax' = TFmax x RateRecovercoeff The default value of this parameter is 130% Set this parameter through ADD CELLOLC / MOD CELLOLC OLC Action z Switching BE Services to Common Channel Target user Based on the user integrate priority The users with the DCH or HSDPA BE services in PS Execution The RNC sends “RB Reconfiguration” message to UE UE make a response by “RB Reconfiguration Complete” Copyright © 2009 Huawei Technologies Co., Ltd All rights reserved The OLC algorithm for switching BE services to common channel operates as follows: Based on the user integrate priority, the OLC sorts all UEs that only have PS services including HSPA and DCH services (except UEs having also a streaming bearer) into a descending order The top N UEs are selected The number of selected UEs is equal to Transfer Common Channel user number If UEs cannot be selected, the action fails The OLC performs the next action The selected UEs are switched to common channel Key parameters z Transfer Common Channel User number Parameter ID: TransCchUserNum The default value of this parameter is Copyright © 2009 Huawei Technologies Co., Ltd All rights reserved Transfer Common Channel User number Parameter ID: TransCchUserNum Value range: to 10 Content: This parameter specifies the transfer common channel user number The default value of this parameter is Set this parameter through ADD CELLOLC / LST CELLOLC / MOD CELLOLC OLC Action z Release of Some RABs Target user Based on the RAB integrate priority DCH services RAB Execution The RNC sends “IU Release Request” message to CN The RNC sends “RRC Connection Release” message to UE Copyright © 2009 Huawei Technologies Co., Ltd All rights reserved OLC Algorithm for the Release of Some RABs in the Uplink: The OLC algorithm for the release of some RABs in the uplink operates as follows: Based on the integrate priority, the OLC sorts all RABs including HSUPA and DCH services into a descending order The top RABs selected If the integrate priorities of some RABs are identical, the RAB with higher rate (current rate for DCH RAB and GBR for HSUPA RAB) in the uplink is selected The number of selected RABs is equal to UL OLC traff release RAB number The selected RABs are released directly OLC Algorithm for the Release of Some RABs in the Downlink The OLC algorithm for the release of some RABs in the downlink operates as follows: Based on the integrate priority, the OLC sorts all RABs into a descending order The top-priority RABs are selected If the integrate priorities of some RABs are identical, the RAB with higher rate (current rate) The number of selected RABs is equal to DL OLC traff release RAB number The selected RABs are directly released Key parameters z UL/DL OLC traff release RAB number Parameter ID: UL/DLOLCTRAFFRELRABNUM The default value of this parameter is Copyright © 2009 Huawei Technologies Co., Ltd All rights reserved UL/DL OLC traff release RAB number Parameter ID: UL/DLOLCTRAFFRELRABNUM Value range: to 10 Content: Either parameter specifies the number of RABs released in a UL or DL OLC release action If the number of RABs that fulfil the criteria for release is smaller than the value of this parameter, then all the RABs that fulfil the criteria are selected The default value of this parameter is Set this parameter through ADD CELLOLC / MOD CELLOLC Summary Load Control Algorithms PUC (Potential User Control) LDB (Intra-Frequency Load Balancing) CAC (Call Admission Control) IAC (Intelligent Admission Control) LDR (Load Reshuffling) OLC (Overload Control) Copyright © 2009 Huawei Technologies Co., Ltd All rights reserved Thank You www.huawei.com Copyright © 2009 Huawei Technologies Co., Ltd All rights reserved