4 Synchronization procedures

25.2143GPPPhysical layer procedures (FDD)Release 17TS

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

4.1 Cell search

During the cell search, the UE searches for a cell and determines the downlink scrambling code and common channel frame synchronization of that cell. How cell search is typically done is described in Annex C.

4.2 Common physical channel synchronization

The radio frame timing of all common physical channels can be determined after cell search.

4.2.1 P-CCPCH radio frame timing

The P-CCPCH radio frame timing is found during cell search and the radio frame timing of all common physical channel are related to that timing as described in [1].

4.2.2 S-CCPCH soft combining timing

Higher layers will provide timing information when S-CCPCHs, each on different RLs,can be soft combined. The timing information allows the UE to determine the L1 combining period that applies to each S-CCPCH. The information also identifies the S-CCPCHs and the RLs that can be soft combined. The set of S-CCPCHs that can be combined does not change during an L1 combining period. When S-CCPCHs can be soft combined, all S-CCPCHs shall contain identical bits in their data fields, although the TFCI fields of the S-CCPCHs may be different. (TFC detection when S-CCPCHs may be soft combined is discussed in [2].) The maximum delay between S-CCPCHs that the UE may combine is set by UE performance requirements. The maximum number of S-CCPCHs that UE may simultaneously combine is defined by the UE capability in [10].

4.2.3 Radio frame timing on the MBSFN layer

MBSFN cluster search and radio frame synchronization on the MBSFN layer can be performed via SCH and follow the same principles as described in Annex C. After the primary scrambling code has been identified, the P-CCPCH can be detected and MBSFN system information can be read.

4.2.4 Secondary serving HS-DSCH cell timing

When the UE is configured with one or more secondary serving HS-DSCH cells, it shall not assume the presence of any common physical channel from these cells other than CPICH. The radio frame timing and timing reference for each of the secondary serving HS-DSCH cells are defined in [1].

4.2.5 HS-DSCH cell timing when Multiflow is configured

When the UE is configured in Multiflow mode, the UE shall not assume any timing relation between the serving HS-DSCH cell and the assisting serving HS-DSCH cell. The UE can only be configured with an assisting serving HS-DSCH cell if that cell is contained in the UE’s active set. If the UE is also configured with multiple uplink frequencies, then the UE can only be configured with an assisting secondary serving HS-DSCH cell if that cell is contained in the UE’s active set on the secondary uplink frequency.

The UE may assume that the serving HS-DSCH cell and the secondary serving HS-DSCH cell, if present, have the same radio frame timing.

The UE may assume that the assisting serving HS-DSCH cell and the assisting secondary serving HS-DSCH cell, if present, have the same radio frame timing.

4.3 DPCCH/DPDCH/F-DPCH synchronization

4.3.1 Synchronization primitives

4.3.1.1 General

For the dedicated channels, synchronization primitives are used to indicate the synchronization status of radio links, both in uplink and downlink. The definition of the primitives is given in the following subclauses.

4.3.1.2 Downlink synchronization primitives

If UL_DTX_Active is FALSE (see clause 6C), layer 1 in the UE shall every radio frame check synchronization status of either the DPCH or the F‑DPCH depending on which is configured. If UL_DTX_Active is TRUE (see clause 6C), the layer 1 in the UE shall check synchronization status of the F-DPCH for each radio frame in which the F-DPCH transmission is known to be present in at least one slot, and for the other radio frames, the layer 1 will not indicate any synchronization status to the higher layers. Synchronization status is indicated to higher layers using the CPHY-Sync-IND and CPHY-Out-of-Sync-IND primitives.

The criteria for reporting synchronization status are defined in two different phases. Each phase is performed by the UE for each individual downlink frequency associated with the activated uplink frequencies. The downlink synchronization primitives are also reported to higher layers for each individual downlink frequency associated with the activated uplink frequencies.

The first phase starts when higher layers initiate physical dedicated channel establishment (as described in [5]) or whenever the UE initiates synchronization procedure A or synchronization procedure AA (as described in subclauses 4.3.2.1 and 4.3.2.3A) and lasts until 160 ms after the downlink dedicated channel is considered established by higher layers (physical channel establishment is defined in [5]). During this time out-of-sync shall not be reported and in-sync shall be reported using the CPHY-Sync-IND primitive if the following criterion is fulfilled:

– The UE estimates the DPCCH quality or the quality of the TPC fields of the F-DPCH frame received from the associated serving HS-DSCH cell (or secondary serving HS-DSCH cell) or the quality of the TPC fields of the F-DPCH frame received from the serving E-DCH cell (or secondary serving E-DCH cell) when E-DCH decoupling is configured and DPCCH2 is not configured over the previous 40 ms period to be better than a threshold Q_in, or over the previous 120ms or 200ms to be better than a threshold Q_inif the Algorithm 3 is configured, when the length of the slot cycle is 3 or 5 respectively. This criterion shall be assumed not to be fulfilled before 40 ms of DPCCH or F-DPCH quality measurements have been collected when either the Algorithm 1 or 2 is configured, or before 120 ms or 200 ms of F-DPCH quality measurements have been collected if the Algorithm 3 is configured, when the length of the slot cycle is 3 or 5 respectively. Q_in is defined implicitly by the relevant tests in [7].

– If both DPCCH and F-DPCH are transmitted when DPCCH2 is configured, then the UE shall use the DPCCH for the estimation of the quality of the TPC fields.

When DL_DCH_FET_Config is configured, the UE shall indicate UL_DPCH_20ms_Mode through the TFCI information carried on the UL DPCCH while both the UE and network transmit as per UL_DPCH_20ms_Mode lasting for 160 ms after the downlink dedicated channel is considered established by higher layers.

The second phase starts 160 ms after the downlink dedicated channel is considered established by higher layers. During this phase both out-of-sync and in-sync are reported as follows.

Out-of-sync shall be reported using the CPHY-Out-of-Sync-IND primitive if any of the following criteria is fulfilled:

– UL_DTX_Active is FALSE (see clause 6C) and the UE estimates the DPCCH quality or the quality of the TPC fields of the F-DPCH frame received from the associated serving HS-DSCH cell (or secondary serving HS-DSCH cell) or the quality of the TPC fields of the F-DPCH frame received from the serving E-DCH cell (or secondary serving E-DCH cell) when E-DCH decoupling is configured and DPCCH2 is not configured over the previous 160 ms period to be worse than a threshold Q_out. Q_out is defined implicitly by the relevant tests in [7]. If both DPCCH and F-DPCH are transmitted when DPCCH2 is configured, then the UE shall use the DPCCH for the estimation of the quality of the TPC fields.

– If PCA has the value 3 or UL_DTX_Active is TRUE (see clause 6C) and the UE estimates the quality of the TPC fields of the F-DPCH from the associated serving HS-DSCH cell (or secondary serving HS-DSCH cell) or the quality of the TPC fields of the F-DPCH frame received from the serving E-DCH cell (or secondary serving E-DCH cell) when E-DCH decoupling is configured and DPCCH2 is not configured over the previous 240 slots in which the TPC symbols are known to be present to be worse than a threshold Q_out. Q_out is defined implicitly by the relevant tests in [7]. If both DPCCH and F-DPCH are transmitted when DPCCH2 is configured, then the UE shall use the DPCCH for the estimation of the quality of the TPC fields.

– The 20 most recently received transport blocks with a non-zero length CRC attached, as observed on all TrCHs using non-zero length CRC mapped to the DPDCH, have been received with incorrect CRC. In addition, over the previous 160 ms, all transport blocks with a non-zero length CRC attached have been received with incorrect CRC. In case no TFCI is used this criterion shall not be considered for the TrCH(s) not using guided detection if they do not use a non-zero length CRC in all transport formats. If no transport blocks with a non-zero length CRC attached are received over the previous 160 ms this criterion shall not be assumed to be fulfilled.

For a DPCH, in-sync shall be reported using the CPHY-Sync-IND primitive if both of the following criteria are fulfilled:

– The UE estimates the DPCCH quality over the previous 160 ms period to be better than a threshold Q_in. Q_in is defined implicitly by the relevant tests in [7].

– At least one transport block with a non-zero length CRC attached, as observed on all TrCHs using non-zero length CRC mapped to the DPDCH, is received in a TTI ending in the current frame with correct CRC. If no transport blocks are received, or no transport block has a non-zero length CRC attached in a TTI ending in the current frame and in addition over the previous 160 ms at least one transport block with a non-zero length CRC attached has been received with a correct CRC, this criterion shall be assumed to be fulfilled. If no transport blocks with a non-zero length CRC attached are received over the previous 160 ms this criterion shall also be assumed to be fulfilled. In case no TFCI is used this criterion shall not be considered for the TrCH(s) not using guided detection if they do not use a non-zero length CRC in all transport formats.

For a F-DPCH, in-sync shall be reported using the CPHY-Sync-IND primitive if any of the following criteria is fulfilled:

– UL_DTX_Active is FALSE (see clause 6C) and the UE estimates the quality of the TPC fields of the F-DPCH frame received from the associated serving HS-DSCH cell (or secondary serving HS-DSCH cell) or the quality of the TPC fields of the F-DPCH frame received from the serving E-DCH cell (or secondary serving E-DCH cell) when E-DCH decoupling is configured and DPCCH2 is not configured over the previous 160 ms period to be better than a threshold Q_in. Q_in is defined implicitly by the relevant tests in [7].

– If PCA has the value 3 or UL_DTX_Active is TRUE (see clause 6C) and the UE estimates the quality of the TPC fields of the F-DPCH from the associated serving HS-DSCH cell (or secondary serving HS-DSCH cell) or the quality of the TPC fields of the F-DPCH frame received from the serving E-DCH cell (or secondary serving E-DCH cell) when E-DCH decoupling is configured and DPCCH2 is not configured over the previous 240 slots in which the TPC symbols are known to be present to be better than a threshold Q_in. Q_in is defined implicitly by the relevant tests in [7].

– If both DPCH and F-DPCH are transmitted when DPCCH2 is configured, then the UE shall use the DPCH in-sync reporting procedure.

How the primitives are used by higher layers is described in [5]. The above definitions may lead to radio frames where neither the in-sync nor the out-of-sync primitives are reported.

4.3.1.3 Uplink synchronization primitives

Layer 1 in the Node B shall every radio frame check synchronization status of all radio link sets. Synchronization status is indicated to the RL Failure/Restored triggering function using either the CPHY-Sync-IND or CPHY-Out-of‑Sync‑IND primitive. Hence, only one synchronization status indication shall be given per radio link set.

The exact criteria for indicating in-sync/out-of-sync is not subject to specification, but could e.g. be based on received DPCCH or DPCCH2 quality or CRC checks. One example would be to have the same criteria as for the downlink synchronization status primitives.

4.3.2 Radio link establishment and physical layer reconfiguration for dedicated channels

4.3.2.1 General

Three synchronization procedures are defined in order to obtain physical layer synchronization of dedicated channels between UE and UTRAN:

– Synchronization procedure A: This procedure shall be used when at least one downlink dedicated physical channel (i.e. a DPCH or F-DPCH) and one uplink dedicated physical channel are to be set up on a frequency and none of the radio links after the establishment/reconfiguration existed on that frequency prior to the establishment/reconfiguration which also includes the following cases :

– the UE was previously on another RAT i.e. inter-RAT handover

– the UE was previously on another frequency i.e. inter-frequency hard handover

– the UE has all its previous radio links removed and replaced by other radio links i.e. intra-frequency hard-handover

– after it fails to complete an inter-RAT, intra- or inter-frequency hard-handover [8], the UE attempts to re-establish [5] all the dedicated physical channels which were already established immediately before the hard-handover attempt. In this case only steps c) and d) of synchronization procedure A are applicable.

– the UE receives an HS-SCCH order to activate the secondary uplink frequency as specified in [2] and the UE is configured with multiple frequencies on the uplink.

For transitions from the CELL_FACH state of a cell to the CELL_DCH state of the same cell,, when synchronization has already been achieved by a synchronization procedure AA and the UE has not already released its uplink common E-DCH resource before the time of transition to CELL_DCH, the synchronization procedure A shall not be executed. Else, the synchronization procedure A shall be executed.

– Synchronization procedure AA: This procedure shall be used when one downlink F-DPCH and uplink dedicated physical channels are to be set up on a frequency as a consequence of an Enhanced Uplink in CELL_FACH procedure.

– Synchronization procedure B: This procedure shall be used when one or several radio links are added to the active set on a frequency and at least one of the radio links prior to the establishment/reconfiguration still exists on that frequency after the establishment/reconfiguration.

– If higher layers indicate that the UE shall not perform any synchronization procedure for timing maintained intra- and inter-frequency hard handover, the UE shall not perform any of the synchronization procedures A or B. If higher layers indicate to the Node B timing maintained intra- or inter-frequency hard handover where the UE does not perform any of the synchronization procedures A, AA or B, the Node B shall perform steps a) and b) of synchronization procedure B.

For all physical layer reconfigurations not listed above, the UE and UTRAN shall not perform any of the synchronization procedures listed above.

The three synchronization procedures are described in subclauses 4.3.2.3, 4.3.2.3A and 4.3.2.4 respectively.

4.3.2.2 Node B radio link set state machine

In Node B, each radio link set can be in three different states: initial state, out-of-sync state and in-sync state. Transitions between the different states are shown in figure 1 below. The state of the Node B at the start of radio link establishment is described in the following subclauses. Transitions between initial state and in-sync state are described in subclauses 4.3.2.3, 4.3.2.3A and 4.3.2.4 and transitions between the in-sync and out-of-sync states are described in subclause 4.3.3.2.

Figure 1: Node B radio link set states and transitions

4.3.2.3 Synchronization procedure A

For each configured uplink frequency, the synchronization establishment procedure, which begins at the time indicated by higher layers (either immediately at receipt of upper layer signalling, or at an indicated activation time), or by an HS-SCCH order to activate the secondary uplink frequency (in the case multiple frequencies are configured on the uplink) is as follows:

a) Each Node B involved in the procedure sets all the radio link sets which are to be set-up for this UE in the initial state.

b) UTRAN shall start the transmission of the downlink DPCCH or F-DPCH corresponding to the activated uplink frequency and may start the transmission of DPDCH if any data is to be transmitted. The initial downlink DPCCH or F-DPCH transmit power is set by higher layers [6]. Downlink TPC commands are generated as described in 5.1.2.2.1.2.

c) The UE establishes downlink chip and frame synchronization of DPCCH or F-DPCH corresponding to the activated uplink frequency, using the P-CCPCH timing and timing offset information notified from UTRAN. For DPCH, frame synchronization can be confirmed using the frame synchronization word. Downlink synchronization status is reported to higher layers every radio frame according to subclause 4.3.1.2.

d) If higher layers indicate the usage of a post-verification period for the primary uplink frequency the UE shall start transmission on the primary uplink frequency immediately when the physical dedicated channel establishment is initiated by the UE. When DL_DCH_FET_Config is configured, the UE shall continue to indicate and transmit as per UL_DPCH_20ms_Mode. Post-verification period shall not be used if the Algorithm 3 is configured. Post-verification period is always used for the secondary uplink frequency, except when Algorithm 3 is configured, or when DTX enhancements is configured, in which case upon successfully receiving an HS-SCCH order to activate the secondary uplink frequency, in-sync shall be reported, and the UE shall start transmission on the secondary uplink frequency immediately according to the DTX settings if configured. In this case, the synchronization status evaluation shall be performed immediately according to the second phase of the downlink synchronization status evaluation.

e) If higher layers do not indicate the usage of a post-verification period for the primary uplink frequency, or if higher layers do indicate the usage of a post-verification period (as specified in 5.1.2.2.1.1) and the post-verification has failed, the UE shall not transmit on the activated uplink frequency until higher layers consider the downlink physical channel established;

– If no activation time for uplink DPCCH has been signalled to the UE or if the UE attempts to re-establish the DPCH after an inter-RAT, intra- or inter-frequency hard-handover failure [5], uplink DPCCH transmission shall start on the activated uplink frequency when higher layers consider the downlink physical channel established;

– If an activation time has been given, uplink DPCCH transmission shall not start on the activated uplink frequency before the downlink physical channel has been established and the activation time has been reached. Physical channel establishment and activation time are defined in [5].

The initial uplink DPCCH transmit power is set by higher layers [5]. In case the synchronization procedure A is executed because the UE receives an HS-SCCH order to activate the secondary uplink frequency, then the initial DPCCH transmit power on the secondary uplink frequency is computed (in dB) as

Uplink DPCCH transmit power = P_DPCCH,1– UE_Sec_Tx_Power_Backoff

where P_DPCCH,1is the DPCCH transmit power on the primary uplink frequency at the start of the transmission on the secondary uplink frequency and UE_Sec_Tx_Power_Backoff is set by higher layers.

In case the UE attempts to re-establish the DPCH after an inter-RAT, intra- or inter-frequency hard-handover failure [5] the initial uplink DPCCH power shall be the same as the one used immediately preceding the inter-RAT, intra- or inter-frequency hard-handover attempt. In case of physical layer reconfiguration the uplink DPCCH power is kept unchanged between before and after the reconfiguration except for inner loop power control adjustments.

A power control preamble shall be applied on the activated uplink frequency as indicated by higher layers. The transmission of the uplink DPCCH power control preamble shall start N_pcp radio frames prior to the radio frame where the uplink DPDCH/E-DPCCH/E-DPDCH transmission starts, where N_pcp is a higher layer parameter set by UTRAN [5]; in case the UE attempts to re-establish the DPCH after an inter-RAT, intra- or inter-frequency hard-handover failure [5] the UE shall use the value of N_pcp as specified in [5] for this case. Note that the transmission start delay between DPCCH and DPDCH/E-DPCCH/E-DPDCH may be cancelled using a power control preamble of 0 length. If higher layers indicate the usage of a post-verification period, and the start of the uplink DPCCH power control preamble with a length of N_pcp radio frames would be in a radio frame later than the first uplink radio frame after physical dedicated channel establishment is initiated by the UE, then the duration of the uplink DPCCH power control preamble shall be equal to or longer than N_pcp radio frames such that the uplink DPCCH power control preamble is transmitted from the first uplink radio frame after physical dedicated channel establishment is initiated by the UE.

The starting time for transmission of DPDCHs/E-DPCCH/E-DPDCHs shall also satisfy the constraints on adding transport channels to a CCTrCH, as defined in [2] subclause 4.2.14, independently of whether there are any bits mapped to the DPDCHs/E-DPCCH/E-DPDCHs. During the uplink DPCCH power control preamble, independently of the selected TFC, no transmission is done on the DPDCH/E-DPCCH/E-DPDCH.

e) UTRAN establishes uplink chip and frame synchronization on the activated uplink frequency. Frame synchronization can be confirmed using the frame synchronization word. Radio link sets remain in the initial state until N_INSYNC_IND successive in-sync indications are received from layer 1, when Node B shall trigger the RL Restore procedure indicating which radio link set has obtained synchronization. When RL Restore has been triggered the radio link set shall be considered to be in the in-sync state. The parameter value of N_INSYNC_IND is configurable, see [6]. The RL Restore procedure may be triggered several times, indicating when synchronization is obtained for different radio link sets.

Note: The total signalling response delay for the establishment of a new DPCH shall not exceed the requirements given in [5] subclause 13.5.

4.3.2.3A Synchronization procedure AA

The synchronization establishment procedure, which begins at the time defined in [1] for the Enhanced Uplink in CELL_FACH state and IDLE mode, is as follows:

a) The Node B involved in the procedure sets the radio link which is to be set-up for this UE in the initial state.

b) UTRAN shall start the transmission of the downlink F-DPCH at the time defined for the Enhanced Uplink in CELL_FACH state and IDLE mode in [1].

c) The UE establishes downlink chip and frame synchronization of F-DPCH, using the P-CCPCH timing and timing offset information notified from UTRAN and based on the timing definition for the Enhanced Uplink in CELL_FACH state and IDLE mode as defined in [1]. Downlink synchronization status is reported to higher layers every radio frame according to subclause 4.3.1.2.

d) The UE shall start transmission on uplink at the time defined for the Enhanced Uplink in CELL_FACH state and IDLE mode in [1] and shall use a post-verification period for confirming the establishment of the downlink physical channel as follows: During the first 40 ms period of the first phase of the downlink synchronization procedure the UE shall control its transmitter according to a downlink F-DPCH quality criterion as follows:

– When the UE estimates the F-DPCH quality over the first 40 ms period of the first phase of the downlink synchronization status evaluation to be worse than a threshold Q_in, the UE shall shut its transmitter off and consider post-verification failed. Q_in is defined implicitly by the relevant tests in [7].

If the post-verification has failed, the UE shall not transmit on uplink and await higher layer orders.

e) UTRAN establishes uplink chip and frame synchronization. Frame synchronization can be confirmed using the frame synchronization word.

4.3.2.4 Synchronization procedure B

For each configured uplink frequency, the synchronization procedure B, which begins at the time indicated by higher layers (either immediately at receipt of upper layer signalling, or at an indicated activation time) is as follows:

a) The following applies to each Node B involved in the procedure:

– New radio link sets are set up to be in initial state.

– If one or several radio links are added to an existing radio link set, this radio link set shall be considered to be in the state the radio link set was prior to the addition of the radio link, i.e. if the radio link set was in the in-sync state before the addition of the radio link it shall remain in that state.

b) UTRAN starts the transmission of the downlink DPCCH/DPDCH or F-DPCH for each new radio link for which the DPCH or F-DPCH is to be transmitted corresponding to the activated uplink frequency at a frame timing such that the frame timing received at the UE will be within T₀  148 chips prior to the frame timing of the uplink DPCCH/DPDCH at the UE. Simultaneously, UTRAN establishes uplink chip and frame synchronization of each new radio link. Frame synchronization can be confirmed using the frame synchronization word. Radio link sets considered to be in the initial state shall remain in the initial state until N_INSYNC_IND successive in-sync indications are received from layer 1, when Node B shall trigger the RL Restore procedure indicating which radio link set has obtained synchronization. When RL Restore is triggered the radio link set shall be considered to be in the in-sync state. The parameter value of N_INSYNC_IND is configurable, see [6]. The RL Restore procedure may be triggered several times, indicating when synchronization is obtained for different radio link sets.

c) The UE establishes chip and frame synchronization of each new radio link. Layer 1 in the UE keeps reporting downlink synchronization status to higher layers every radio frame according to the second phase of subclause 4.3.1.2. For DPCH, frame synchronization can be confirmed using the frame synchronization word for the radio link where the DPCH is transmitted.

4.3.3 Radio link monitoring

4.3.3.1 Downlink radio link failure

The downlink radio links where F-DPCH and/or DPCH is transmitted shall be monitored by the UE, to trigger radio link failure procedures. The downlink radio link failure criteria is specified in [5], and is based on the synchronization status primitives CPHY-Sync-IND and CPHY-Out-of-Sync-IND, indicating in-sync and out-of-sync respectively.

4.3.3.2 Uplink radio link failure/restore in CELL_DCH state

The uplink radio link sets are monitored by the Node B, to trigger radio link failure/restore procedures. Once the radio link sets have been established, they will be in the in-sync or out-of-sync states as shown in figure 1 in subclause 4.3.2. 2. Transitions between those two states are described below.

The uplink radio link failure/restore criteria is based on the synchronization status primitives CPHY-Sync-IND and CPHY-Out-of-Sync-IND, indicating in-sync and out-of-sync respectively. Note that only one synchronization status indication shall be given per radio link set.

When the radio link set is in the in-sync state, Node B shall start timer T_RLFAILURE after receiving N_OUTSYNC_IND consecutive out-of-sync indications. Node B shall stop and reset timer T_RLFAILURE upon receiving successive N_INSYNC_IND in-sync indications. If T_RLFAILURE expires, Node B shall trigger the RL Failure procedure and indicate which radio link set is out-of-sync. When the RL Failure procedure is triggered, the state of the radio link set change to the out-of-sync state.

When the radio link set is in the out-of-sync state, after receiving N_INSYNC_IND successive in-sync indications Node B shall trigger the RL Restore procedure and indicate which radio link set has re-established synchronization. When the RL Restore procedure is triggered, the state of the radio link set change to the in-sync state.

The specific parameter settings (values of T_RLFAILURE, N_OUTSYNC_IND, and N_INSYNC_IND) are configurable, see [6].

4.3.3.2A Uplink radio link failure/restore in CELL_FACH state and IDLE mode

The uplink radio link failure/restore is under the control of the Node B.

4.3.4 Transmission timing adjustments

During a connection the UE may adjust its DPDCH/DPCCH transmission time instant.

When the UE autonomously adjusts its DPDCH/DPCCH transmission time instant, it shall simultaneously adjust the HS-DPCCH, DPCCH2, E-DPCCH, E-DPDCH, S-DPCCH, S-E-DPCCH and S-E-DPDCH transmission time instant by the same amount so that the relative timing between DPCCH/DPDCH/DPCCH2 and HS-DPCCH is kept constant and that DPCCH/DPDCH and DPCCH2 and E-DPCCH/E-DPDCH and S-DPCCH and S-E-DPCCH/S-E-DPDCH remain time aligned.

If the receive timing for any downlink DPCCH/DPDCH or F-DPCH in the current active set has drifted, so the time between reception of the downlink DPCCH/DPDCH in question and transmission of uplink DPCCH/DPDCH lies outside the valid range, L1 shall inform higher layers of this, so that the network can be informed of this and downlink timing can be adjusted by the network.

The maximum rate of uplink TX time adjustment, and the valid range for the time between downlink DPCCH/DPDCH or F-DPCH reception and uplink DPCCH/DPDCH transmission in the UE are defined by the requirements specified in [8].

When the UE’s time reference cell for HSDPA Multiflow is changed, the UE shall adjust its HS-DPCCH transmission timing to comply with the definitions in [1].