6A RRC Connection Control

25.1233GPPRelease 17Requirements for support of radio resource management (TDD)TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

6A.1 RRC re-establishment

6A.1.1 Introduction

RRC connection re-establishment is needed, when a UE in CELL_DCH state loses radio connection due to radio link failure. The procedure when a radio link failure occurs in CELL_DCH state is specified in [16].

6A.1.2 Requirements

6A.1.2.1 3.84Mcps TDD option

The requirements in this section are applicable when the UE performs a RRC connetion re-establishment to a cell belonging to any of the frequencies present in the previous monitored set.

The UE moves from CELL_DCH to CELL_FACH state and shall be capable of sending a RRC CELL UPDATE message using the cause value "radio link failure" within T_RE-ESTABLISH seconds from when the radio link failure occurred.

T_RE-ESTABLISHequals the RRC procedure performance value T_{RRC-RE-ESTABLISH} according to [16] plus the UE re-establishment delay T_{UE-RE-ESTABLISH-REQ} specified in 6A.1.2.1.

T_RE-ESTABLISH = T_{RRC-RE-ESTABLISH} + T_{UE-RE-ESTABLISH-REQ}

6A.1.2.1.1 UE re-establishment delay requirement

For UTRA TDD, the UE re-establishment delay T_{UE-RE-ESTABLISH-REQ} is defined as the time between the moment when radio link failure is considered by the UE to when the UE starts sending the RRC CELL UPDATE message to the UTRAN on RACH.

T_{UE-RE-ESTABLISH-REQ} is depending on whether the target cell is known by the UE or not. A cell shall be considered known by the UE if either or both of the following conditions are true:

– the UE has had a radio link connected to the cell during the last 5 seconds

– the cell has been measured by the UE during the last 5 seconds.

In case that the target cell is known by the UE, the UE re-establishment delay shall be less than

T_{UE-RE-ESTABLISH-REQ-KNOWN} = 50+T_SEARCH-KNOWN+ T_SI ms

In case that the target cell is not known by the UE, the UE re-establishment delay shall be less than,

T_{UE-RE-ESTABLISH-REQ-UNKNOWN} = 50+T_{SEARCH-UNKNOWN}*NF + T_SI ms

in case that the target cell is not known by the UE;

where,

T_{SEARCH -KNOWN} Equal to 100 ms, the time it takes for the UE to search for the known target cell

T_{SEARCH -UNKNOWN} Equal to 800 ms, the time it takes for the UE to search for the unknown target cell

T_SI The time required for receiving all the relevant system information data according to the reception procedure and the RRC procedure performance value of system information blocks defined in [16] for a UTRAN cell.

NF The number of different frequencies in the previous (old) monitored set.

These requirements assume radio conditions to be sufficient, so that reading of system information can be done without errors.

6A.1.2.2 1.28Mcps TDD option

The requirements in this section are applicable when the UE performs a RRC connection re-establishment to a cell belonging to any of the frequencies present in the previous monitored set.

The UE moves from CELL_DCH to CELL_FACH state and shall be capable of sending a CELL UPDATE message using the cause "radio link failure" within T_RE-ESTABLISH seconds from when the radio link failure occurred.

T_RE-ESTABLISHequals theRRC procedure delay (T_{RRC-RE-ESTABLISH}) according to TS25.331 plusthe UE Re-establishment delay requirement (T_{UE-RE-ESTABLISH-REQ}), specified in 6A.1.2.2.1.

T_RE-ESTABLISH= T_{RRC-RE-ESTABLISH}+ T_{UE-RE-ESTABLISH-REQ}

6A.1.2.2.1 Re-establishment delay requirement

The UE Re-establishment delay requirement (T_{UE-RE-ESTABLISH-REQ}) is defined as the time between the moment when radio link failure is considered by the UE to when the UE starts to send SYNC-UL in the UpPTS for sending a CELL UPDATE message using the cause "radio link failure".

T_{RE-ESTABLISH-REQ} is depending on whether the target cell is known by the UE or not. A cell is known if either or both of the following conditions are true:

– the UE has had a dedicated connection to the cell during the last 5 seconds

– the cell has been measured by the UE during the last 5 seconds

The UE Re-establishment delay shall be less than

T_{UE-RE-ESTABLISH-REQ-KNOWN} =50ms+T_search + T_SI+T_RA

in case that the target cell is known by the UE, and

T_UE–_{RE-ESTABLISH-REQ-UNKNOWN} =50ms+T_search*NF + T_SI +T_RA

in case that the target cell is unknown by the UE

where

– T_search is the time it takes for the UE to search the cell.

– T_search =100 ms if the target cell is known by the UE, and

– T_search =800 ms if the target cell is not known by the UE.

– T_SI is the time required for receiving all the relevant system information data according to the reception procedure and the RRC procedure delay of system information blocks defined in 25.331 for a UTRAN cell (ms)

– T_RA= The additional delay caused by the random access procedure.

– NF is the number of different frequencies in the monitored set.

This requirement assumes radio conditions to be sufficient, so that reading of system information can be done without errors.

6A.1.2.3 7.68Mcps TDD option

The requirements in this section are applicable when the UE performs a RRC connetion re-establishment to a cell belonging to any of the frequencies present in the previous monitored set.

T_RE-ESTABLISHequals the RRC procedure performance value T_{RRC-RE-ESTABLISH} according to [16] plus the UE re-establishment delay T_{UE-RE-ESTABLISH-REQ} specified in 6A.1.2.3.

T_RE-ESTABLISH = T_{RRC-RE-ESTABLISH} + T_{UE-RE-ESTABLISH-REQ}

6A.1.2.3.1 UE re-establishment delay requirement

T_{UE-RE-ESTABLISH-REQ} is depending on whether the target cell is known by the UE or not. A cell shall be considered known by the UE if either or both of the following conditions are true:

– the UE has had a radio link connected to the cell during the last 5 seconds

– the cell has been measured by the UE during the last 5 seconds.

In case that the target cell is known by the UE, the UE re-establishment delay shall be less than

T_{UE-RE-ESTABLISH-REQ-KNOWN} = 50+T_SEARCH-KNOWN+ T_SI ms

In case that the target cell is not known by the UE, the UE re-establishment delay shall be less than,

T_{UE-RE-ESTABLISH-REQ-UNKNOWN} = 50+T_{SEARCH-UNKNOWN}*NF + T_SI ms

in case that the target cell is not known by the UE;

where,

T_{SEARCH -KNOWN} Equal to 100 ms, the time it takes for the UE to search for the known target cell

T_{SEARCH -UNKNOWN} Equal to 800 ms, the time it takes for the UE to search for the unknown target cell

NF The number of different frequencies in the previous (old) monitored set.

These requirements assume radio conditions to be sufficient, so that reading of system information can be done without errors.

6A.2 Transport format combination selection in UE

6A.2.1 Introduction

When the UE estimates that a certain TFC would require more power than the maximum transmit power, it shall limit the usage of transport format combinations for the assigned transport format combination set. This in order to make it possible for the network operator to maximise the coverage. The transport format combination selection in UE is described in [13].

6A.2.1.1 3.84 Mcps TDD option

Void.

6A.2.1.2 1.28 Mcps TDD option

The E-TFC selection delay is defined as the time from the moment SS starts to send TPC_Cmd=UP to the moment UE E-TFCI becomes 0. UE E-TFC selection is specified in section 11.9.1.4 in TS25.321.

6A.2.1.3 7.68 Mcps TDD option

Void.

6A.2.2 Requirements

6A.2.2.1 3.84 Mcps TDD option

In the case of a single CCTrCH or multiple CCTrCHs having mutually exclusive timeslot assignments, the UE shall consider the Eliminiation criterion for a given TFC of a CCTrCH to be fulfilled if for 3 successive frames the estimated UE transmit power is greater than the Maximum UE transmitter power for at least one timeslot associated with the CCTrCH in each frame.

. In the case of multiple CCTrCHs not having mutually exclusive timeslot assignments, if for a given CCTrCH for 3 successive frames the estimated UE transmit power is greater than the Maximum UE transmitter power for at least one timeslot associated with the CCTrCH in each frame, the UE shall consider the Elimination criterion for a given TFC to be fulfilled if the use of this TFC will cause the estimated UE transmit power to continue to be greater than the Maximum UE transmitter power in at least one timeslot associated with the CCTrCH.

In the case of multi-frame operation of UL Physical Channels, the UE shall only consider active frames for the evaluation of the Elimination criterion.

If the Elimination criterion for a given TFC is fulfilled, the MAC in the UE shall consider that the TFC is in Excess-Power state for the purpose of TFC selection.

MAC in the UE shall indicate the available bitrate for each logical channel to upper layers within T_notify from the moment the Elimination criterion was fulfilled.

The UE shall not consider the Recovery criterion for a given TFC to be fulfilled until the use of this TFC will not cause the estimated UE transmit power to be greater than the Maximum UE transmitter power for all UL timeslots associated with the TFC for a minimum of 3 successive frames.

In the case of multi-frame operation of UL Physical Channels, the UE shall only consider active frames for the evaluation of the Recovery criterion.

. If the Recovery criterion for a given TFC is fulfilled, the MAC in the UE shall consider that the TFC is in Supported state for the purpose of TFC selection.

MAC in the UE shall indicate the available bitrate for each logical channel to upper layers within T_notify from the moment the Recovery criterion was fulfilled.

The UE shall consider the Blocking criterion for a given TFC to be fulfilled at the latest at the start of the longest uplink TTI after the moment at which the TFC will have been in Excess-Power state for a duration of

(T_notify + T_modify+ T_{L1_proc}).

where:

T_notify equals 15 ms, and

T_modify equals MAX(T_{adapt_max},T_TTI), and

T_{L1 proc} equals 35 ms, and

T_{adapt_max} equals MAX(T_{adapt_1}, T_{adapt_2}, …, T_{adapt_N}), and

N equals the number of logical channels that need to change rate, and

T_{adapt_n} equals the time it takes for higher layers to provide data to MAC in a new supported bitrate, for logical channel n. Table 6A.1 defines T_adapt times for different services. For services where no codec is used T_adapt shall be considered to be equal to 0 ms.

Table 6A.1: T_adapt

Service	T_adapt [ms]
UMTS AMR	40
UMTS AMR 2	60

T_TTI equals the longest uplink TTI of the selected TFC (ms).

The Maximum UE transmitter power is defined as follows

Maximum UE transmitter power = MIN(Maximum allowed UL TX Power, UE maximum transmit power)

where

Maximum allowed UL TX Power is set by UTRAN and defined in [16], and

UE maximum transmit power is defined by the UE power class, and specified in [5].

6A.2.2.2 1.28 Mcps TDD option

The UE shall continuously evaluate based on the Elimination, Recovery and Blocking criteria defined below, how TFCs can be used for the purpose of TFC selection. The evaluation shall be performed using the estimated UE transmit power of a given TFC. The UE transmit power estimation shall be made using the UE transmitted power measured over the measurement period and the gain factors of the corresponding TFC.

The UE shall consider the Eliminiation criterion for a given TFC to be fulfilled if the estimated UE transmit power needed for this TFC is greater than the Maximum UE transmitter power for at least X out of Y successive measurement periods. The MAC in the UE shall consider that the TFC is in Excess-Power state for the purpose of TFC selection.

MAC in the UE shall indicate the available bitrate for each logical channel to upper layers within [15 ms] from the moment the Elimination criterion was fulfilled.

The UE shall consider the Recovery criterion for a given TFC to be fulfilled if the estimated UE transmit power needed for this TFC has not been greater than the Maximum UE transmitter power for at least Y successive measurement periods. The MAC in the UE shall consider that the TFC is in Supported state for the purpose of TFC selection.

MAC in the UE shall indicate the available bitrate for each logical channel to upper layers within T_notify from the moment the Recovery criterion was fulfilled.

where:

T_notify equals [15] ms, and

T_modify equals MAX(T_{adapt_max},T_TTI), and

T_{L1 proc} equals 15 ms, and

T_{adapt_max} equals MAX(T_{adapt_1}, T_{adapt_2}, …, T_{adapt_N}), and

N equals the number of logical channels that need to change rate, and

T_{adapt_n} equals the time it takes for higher layers to provide data to MAC in a new supported bitrate, for logical channel n. Table 6A.2 defines T_adapt times for different services. For services where no codec is used T_adapt shall be considered to be equal to 0 ms.

Table 6A.2: T_adapt

Service	T_adapt [ms]
AMR	40

T_TTI equals the longest uplink TTI of the selected TFC (ms).

E-TFC selection is allowed only in the CELL_DCH state.

UE will calculate the power of E-PUCH according to the expressions as below, which is stated in TS 25.224 clause 4.2.2.4)

maximum supported transmission power for a certain E-TFC=min(maximum UE transmission power, E-PUCH transmission power)。

where，maximum UE transmission power is the maximum transmission power of UE.

E-PUCH transmission power is calculated by the expressions above with β_e = (AG + α_e)。

The UE shall consider the Blocking criterion for a given E-TFC to be fulfilled if the estimated power of E-PUCH is larger than maximum supported transmission power for a certain E-TFC.

The Maximum UE transmitter power is defined as follows

Maximum UE transmitter power = MIN(Maximum allowed UL TX Power, UE maximum transmit power)

where

Maximum allowed UL TX Power is set by UTRAN and defined in [16], and

UE maximum transmit power is defined by the UE power class, and specified in [5].

6A.2.2.3 7.68 Mcps TDD option

In the case of multiple CCTrCHs not having mutually exclusive timeslot assignments, if for a given CCTrCH for 3 successive frames the estimated UE transmit power is greater than the Maximum UE transmitter power for at least one timeslot associated with the CCTrCH in each frame, the UE shall consider the Elimination criterion for a given TFC to be fulfilled if the use of this TFC will cause the estimated UE transmit power to continue to be greater than the Maximum UE transmitter power in at least one timeslot associated with the CCTrCH.

In the case of multi-frame operation of UL Physical Channels, the UE shall only consider active frames for the evaluation of the Elimination criterion.

If the Elimination criterion for a given TFC is fulfilled, the MAC in the UE shall consider that the TFC is in Excess-Power state for the purpose of TFC selection.

MAC in the UE shall indicate the available bitrate for each logical channel to upper layers within T_notify from the moment the Elimination criterion was fulfilled.

In the case of multi-frame operation of UL Physical Channels, the UE shall only consider active frames for the evaluation of the Recovery criterion.

If the Recovery criterion for a given TFC is fulfilled, the MAC in the UE shall consider that the TFC is in Supported state for the purpose of TFC selection.

MAC in the UE shall indicate the available bitrate for each logical channel to upper layers within T_notify from the moment the Recovery criterion was fulfilled.

(T_notify + T_modify+ T_{L1_proc}).

where:

T_notify equals 15 ms, and

T_modify equals MAX(T_{adapt_max},T_TTI), and

T_{L1 proc} equals 35 ms, and

T_{adapt_max} equals MAX(T_{adapt_1}, T_{adapt_2}, …, T_{adapt_N}), and

N equals the number of logical channels that need to change rate, and

T_{adapt_n} equals the time it takes for higher layers to provide data to MAC in a new supported bitrate, for logical channel n. Table 6A.3 defines T_adapt times for different services. For services where no codec is used T_adapt shall be considered to be equal to 0 ms.

Table 6A.3: T_adapt

Service	T_adapt [ms]
UMTS AMR	40
UMTS AMR 2	60

T_TTI equals the longest uplink TTI of the selected TFC (ms).

The Maximum UE transmitter power is defined as follows

Maximum UE transmitter power = MIN(Maximum allowed UL TX Power, UE maximum transmit power)

where

Maximum allowed UL TX Power is set by UTRAN and defined in [16], and

UE maximum transmit power is defined by the UE power class, and specified in [5].

6A.3 Maximum allowed UL TX Power

6A.3.1 Introduction

UTRAN may limit the power the UE is using on the uplink by setting the maximum allowed UL TX power IE defined in [16].

6A.3.2 Requirements

6A.3.2.1 3.84 Mcps option

For each measurement period, the UE shall with the use of the UE transmitted power measurement, estimate if it has reached the Maximum allowed UL TX Power or not. With tolerances as defined for the UE transmitted power measurement accuracy (section 9.1.2.1.1), the UE output power shall not exceed the Maximum allowed UL TX Power, as set by the UTRAN.

For UE output powers that are outside the range covered by the UE transmitted power measurement the UE output power shall not exceed the Maximum allowed UL TX Power with more than the tolerances specified for the UL Power Control in [5].

6A.3.2.2 1.28 Mcps option

6A.3.2.3 7.68 Mcps option

6A.4 Random Access

6A.4.1 Introduction

The random access procedure is used when establishing the layer 1 communication between the UE and UTRAN. The random access shall provide a fast access but without disturbing ongoing connections. The random access is specified in section 5.6 of TS 25.224 and the control of the RACH transmission is specified in section 11.2.3.2 of TS 25.321. A random access transmit sequence is described in section 6.7.3.2 of TS 25.303.

6A.4.2 Requirements

6A.4.2.1 3.84 Mcps TDD option

Void.

6A.4.2.2 1.28 Mcps TDD option

The UE shall have capability to calculate initial power according to the open loop algorithm and apply this power level at the first UpPCH and increase the power on additional UpPCH:

PUpPCH = LPCCPCH + PRXUpPCHdes + (i-1)* Pwrramp

The absolute power applied to the first UpPCH shall have the accuracy as specified in table 6.4.1.2 of TS 25.102. The accuracy is ± 9dB in the case of normal condition or ±12dB in the case of extreme condition.

The relative power, which is the power difference for UpPCH ramping. The test requirement of the power difference for all SYNC_UL ramping is 0~3dB (Pwr_ramp). The relative power applied to additional UpPCH shall have an accuracy as below, which is referred to 6.5.2.1 of TS 25.101.

Table 6A.4: Transmitter power difference tolerance

Power step size Pwrramp [dB]	Transmitter power difference tolerance [dB]
0	+/- 1
1	+/- 1
2	+/- 1.5
3	+/- 2

The UE shall stop transmit UpPCH when FPACH has been received correctly or if the maximum number of UpPCH has been reached. When FPACH has been received correctly the UE shall transmit PRACH.

6A.4.2.2.1 Correct behaviour when receiving FPACH

The UE shall stop transmitting UpPCH when FPACH has been received correctly and then transmit a PRACH message.

The absolute power applied to the first UpPCH shall have an accuracy as specified in table 6.3A of TS 25.102. The relative power applied to additional UpPCH shall have an accuracy as below.

6A.4.2.2.2 Correct behaviour when reaching maximum allowed UL transmit power

The UE shall not exceed the maximum allowed UL TX power configured by the UTRAN.

The absolute power of any UpPCH shall not exceed the maximum allowed UL TX power with more than specified in section 6A.3.

6A.4.2.3 7.68 Mcps TDD option

Void.