LTE eRAN2.1 Connection Management Feature Confidential Information of Huawei. No Spreading Without Permission LTE eRAN2.1 Connection Management Feature Confidential Information of Huawei. No Spreading Without Permission LTE eRAN2.1 Connection Management Feature Confidential Information of Huawei. No Spreading Without Permission LTE eRAN2.1 Connection Management Feature Connection management in the LTE system involves management of the connections between the UE, eNodeB, and MME. The connection management is performed in both control plane and user plane. Essentially ,the signaling connection is the precondition for all the service procedures, it is always setup firstly. The initial signaling connection is without security. Confidential Information of Huawei. No Spreading Without Permission Confidential Information of Huawei. The signaling between UE and MME is called NAS signaling.LTE eRAN2. there is no a direct connection between the UE and MME.1 Connection Management Feature The control plane messages are terminated in eNodeB or MME.After the security establishment. No Spreading Without Permission .The signaling connection between UE and eNodeB is RRC connection. Actually. The initial signaling connection is without security. a S1 dedicated connection is setup. so the NAS signaling transmission is based on the RRC connection and S1 interface dedicated signaling connection . the section between the UE and the eNodeB is called RB. In the EPS bearer. Confidential Information of Huawei. and the section between the eNodeB and the Serving Gateway (S-GW) is S1 bearer. RB and S1 bearer are collectively referred to as E-RAB.LTE eRAN2. the services between a UE and a Packet Data Network (PDN)-Gateway (GW) with the same QoS class are referred to as an Evolved Packet System (EPS) bearer.1 Connection Management Feature In the user plane. No Spreading Without Permission . and releases the ERAB. modifies. Confidential Information of Huawei. Through RB management. No Spreading Without Permission . After the connection in the control plane is complete. location update. After the RA procedure is complete.1 Connection Management Feature The procedure for setting up all the connections is shown in the slide: RA is triggered by a UE when the UE needs to communicate with the network for purposes such as service request. and paging. the connection between the UE and the MME in the control plane is started. Connection in the control plane consists of Radio Resource Control (RRC) signaling connection and dedicated S1 connection. the MME causes the eNodeB to establish E-UTRAN Radio Access Bearer (E-RAB) in the case of service request. the eNodeB establishes.LTE eRAN2. LTE eRAN2.1 Connection Management Feature Confidential Information of Huawei. No Spreading Without Permission . Confidential Information of Huawei.1 Connection Management Feature Random access is always the first step in the connection setup procedure. We call random access “RA” for short. During RA. No Spreading Without Permission . Through the RA procedure. and then the system responds to the request and allocates a Random Access Channel (RACH). RA is performed before a UE begins to communicate with the network. the UE can obtain the uplink synchronization signals from the network and request dedicated resources for data transmission. It is also useful in some other scenarios such as handover. a UE requests access to the system.LTE eRAN2. No Spreading Without Permission . the UE initiates RA in the target cell. the UE initiates RA. When a UE in RRC_CONNECTED mode needs to transmit uplink data to an eNodeB and finds that it is in the uplink synchronization loss state. Case 4: downlink data arrival. the UE initiates RA. Case 2: RRC connection reestablishment. When an eNodeB needs to transmit downlink data to a UE in RRC_CONNECTED mode and finds that the UE is in the uplink synchronization loss state. the eNodeB instructs the UE to initiate RA. When a UE performs handover.1 Connection Management Feature RA is performed in the following scenarios: Case 1: initial RRC connection establishment. When a radio link fails. the UE initiates RA. When a UE is changed from RRC_IDLE mode to RRC_CONNECTED mode. Case 3: handover. the UE needs to reestablish RRC connection.LTE eRAN2. Case 5: uplink data arrival. Confidential Information of Huawei. In this case. Therefore.1 Connection Management Feature Depending on whether contention is introduced. case 4 and case 6 are non-contention-based RA. non-contention-based RA becomes contention-based RA. No Spreading Without Permission . there are no preamble conflicts. and there may be conflicts among the preambles. no corresponding logical channel is available for the preambles. Therefore. The RACH is used only for the transmission of RA preambles. Therefore. The Physical Random Access Channel (PRACH) bears the RACH. The preambles are handled in the Medium Access Control (MAC) layer. and each preamble is dedicated to a UE. When the dedicated preambles that are allocated by the eNodeB are used up. and case 5 are contention-based RA. case 2. the RA procedure can be categorized into the following types: Contention-based RA: The access preambles are generated by UEs. The PRACH has fixed time and frequency resources. which can be obtained from the common channel configuration parameters in the System Information Block-2 (SIB2). Case 1.LTE eRAN2. Case 3. the eNodeB needs to resolve the contention for UE access. Confidential Information of Huawei. Non-contention-based RA: The access preambles are allocated to UEs by the eNodeB. the UE must obtain the PRACH configuration. the eNodeB applies for Temporary Cell RNTI (C-RNTI) and uplink and downlink scheduling resources. If it expires or is not specified. For contention-based RA. the data could be “RRC Connection Request”.1 Connection Management Feature The procedure is divided into four steps: UE transmitting an RA preamble. such as “RRC Setup Complete”. the UE directly uploads an RA preamble if the PRACH configuration is specified and does not expire. Upon receiving the preamble. No Spreading Without Permission . Then. The UE transmits uplink scheduled data over the UL-SCH. The contention resolution is generated in the RRC layer.LTE eRAN2. the eNodeB transmits the contention resolution to the UE through the CCCH or DCCH over the DL-SCH. Confidential Information of Huawei. then send to the UE. No Spreading Without Permission .1 Connection Management Feature The UE transmits an RA preamble over the PRACH with the transmit power of PPRACH。 RA preamble is a burst of bits. it includes: Cyclic Prefix (CP) The length of a CP is Tcp preamble sequence The length of a preamble sequence is Tseq Confidential Information of Huawei.LTE eRAN2. which are used for cells of different radii. and LTE TDD supports preamble formats 0-4. No Spreading Without Permission . Confidential Information of Huawei.1 Connection Management Feature There are five RA preamble formats. and the cell radius can be set through the CellRadius parameter. LTE FDD supports preamble formats 0-3. The preamble format can be set through the PreambleFmt parameter.LTE eRAN2. LTE eRAN2.1 Connection Management Feature Parameter ID Description PreambleFmt CellRadius Indicates the preamble format used in the cell. No Spreading Without Permission . Indicates the radius of the cell. Confidential Information of Huawei. No Spreading Without Permission . whose value ranges from 0 to 837. the 64 preamble sequences are divided into the random preamble sequence group and dedicated preamble sequence group. To improve uplink resource allocation. The Contention-based Random Access can choose the random preamble group sequence only. a preamble in the group has an even probability to be selected. Confidential Information of Huawei. The logical index of the ZC sequence is cyclic. the random preamble sequence groups are further divided into preamble sequence group A and preamble sequence group B. or RA preamble sequence group A is selected if any of the following conditions is not met: Random preamble sequence group B exists. The size of the transport block msg3 in the scheduled data transmission is larger than the threshold of random preamble sequence group A.LTE eRAN2. In the system information. That is. After a random preamble sequence group is selected. The number of dig its for cyclic shifts is determined by the eNodeB according to the cell type and cell radius. The logical index of the ZC sequence and configured cyclic shift value are transmitted in the PRACH configurations in the SIB2. The logical index of the ZC sequence is determined by RootSequenceIdx. The path loss is smaller than the corresponding threshold.1 Connection Management Feature Each cell has 64 preamble sequence The is defined by a cyclic shift of the Zadoff-Chu (ZC) sequence. When the UE obtains the PRACH configuration. the logical index 0 is consecutive to 837. The RACH-related parameters consist of the number of random preamble sequences and proportion of random preamble sequence group A. RA preamble sequence group B is selected if the following conditions are met. Each logical root sequence corresponds to a physical root sequence. Confidential Information of Huawei. which is used to derive the preamble sequence.1 Connection Management Feature Parameter ID Description RootSequenceIdx Indicates the logical root sequence index.LTE eRAN2. No Spreading Without Permission . the UE performs RA again if the number of RA attempts is smaller than the maximum number of attempts. No Spreading Without Permission . the RA procedure fails. A message on the DL-SCH can carry multiple RA responses to be transmitted to multiple use. If the number of RA attempts is not smaller. or if all received RA responses contain RA preamble identifiers that do not match the transmitted RA preamble. the UE infers that the response reception fails.1 Connection Management Feature Upon receiving the UE preamble. and Temporary C-RNTI. If the UE does not receive a response within the TTI. Then. Timing Alignment Information. Confidential Information of Huawei. If the received RA-Preamble Identifier is consistent with the identifier that the UE previously sent. the UE infers that the response is successful.LTE eRAN2. For the UE . the eNodeB transmits an RA response over the Downlink Shared Channel (DL-SCH). The response contains RA-Preamble Identifier. the UE transmits uplink scheduled data. Then. the UE monitors the Physical Dedicated Control Channel (PDCCH) in the Transmission Time Interval (TTI) until it obtains the required RA response. Initial UL Grant. The RRC Connection Reestablishment message is transmitted in TM in the RLC layer. and the NAS message is not carried in the message.1 Connection Management Feature With the grant . The RRC Handover Confirm message and C-RNTI are transmitted over the DCCH.At least C-RNTI of the UE is transmitted. RRC connection reestablishment. The message is not segmented. No Spreading Without Permission . Buffer Status Report (BSR) is also carried. Target cell access that is contention-based during a handover procedure without a dedicated RA preamble.the UE transmits uplink scheduled data over the UL-SCH. Confidential Information of Huawei. The carried signaling and information in the transport block vary according to the RA scenario: Initial RRC connection establishment.The RRC Connection Request message is transmitted over the CCCH in TM in the RLC layer.LTE eRAN2. For other scenarios. NAS UE_ID is carried in the message. is specified in the preamble. The size of the transport block. and if required. which is not smaller than 80 bits. The scheduled data could be “RRC Connection Setup Request” message. and the message is not segmented. After the UE receives the contention resolution. Temporary C-RNTI is obtained when the UE monitors the PDCCH. The UE monitors the PDCCH before the timer expires.1 Connection Management Feature The contention resolution is generated in the RRC layer. the UE performs RA again if the number of RA attempts is smaller than the maximum number of attempts.LTE eRAN2. Confidential Information of Huawei. In the following situations. the UE infers that the contention resolution fails. No Spreading Without Permission . If the contention resolution timer expires. the eNodeB transmits the contention resolution to the UE through the CCCH or DCCH over the DL-SCH. In addition. Then. the UE infers that the contention resolution is successful and it notifies the upper layer and stops the : The UE obtains the C-RNTI when monitoring the PDCCH. the MAC Packet Data Unit (MAC PDU) is successfully decoded. Then. the contention resolution timer starts. the UE transmits the dedicated preamble that is allocated. Confidential Information of Huawei. at least Timing Alignment Information and Initial UL Grant are contained in the RA response. Over the RACH. The dedicated signaling could be a HO COMMAND message transmitted by the source eNodeB carries an allocated preamble. at least Timing Alignment Information and RAPreamble Identifier are contained in the RA response. During handover. No Spreading Without Permission .1 Connection Management Feature The non-contention-based RA procedure is as follows: The eNodeB allocates an RA preamble to the UE in dedicated signaling. The eNodeB transmits an RA response over the DL-SCH. Upon downlink data arrival.LTE eRAN2. however. however. No Spreading Without Permission . Generally. the probability of RACH collision is low. the RACH does not cause any interference to other uplink channels. The backoff control. and some UEs fail to access the network. After the backoff time ends. backoff control is introduced in the LTE system to control the time for the UE to retransmit preambles. If retransmission is required. the UE retransmits the preamble. the LTE system has lower overload control requirement than earlier mobile communications systems.1 Connection Management Feature In the LTE system. Therefore. If excessive UEs are admitted on a PRACH. the UE selects a value between 0 and the received backoff value as its backoff time. The eNodeB notifies the UE of a backoff value through the RA response. is not implemented in the following two cases: During the initial preamble transmission During the preamble retransmission in non-contention-based RA Confidential Information of Huawei.LTE eRAN2. To reduce the conflict probability. UE preamble conflict may occur. the algorithm dynamically adjusts the time-domain resource allocation based on the load on the RACH. When this switch is set to OFF. the algorithm uses the initial configuration and does not perform dynamic adjustments. No Spreading Without Permission . UnsyncRaSwitch: Indicates the switch that is used to control the random access mode applied when UEs are out of synchronization in the uplink. When this switch is set to ON. the eNodeB instructs UEs to use the non-contention-based random access mode upon DL data arrival in the case of out-of-synchronization. When this switch is set to OFF.1 Connection Management Feature Parameter Description ID RachAlg oSwitch RaGrpAdjSwitch: Indicates the switch that is used to enable and disable the group adjustment algorithm. the algorithm uses the initial configuration and does not perform dynamic adjustments. When this switch is set to ON. When this switch is set to OFF. RaTrAdjSwitch: Indicates the switch that is used to enable and disable the time-domain resource adjustment algorithm. the eNodeB enables reuse of dedicated preambles between UEs based on the MaskIndex parameter. HoRaSwitch: Indicates the switch that is used to control the random access mode applied during handovers. MaksIdxSwitch: Indicates the switch that is used to control the reuse of dedicated preambles between UEs. BackOffSwitch: Indicates the switch that is used to enable and disable the backoff control algorithm. the eNodeB allocates one dedicated preamble to only one user at a given time. Confidential Information of Huawei. When this switch is set to ON. When this switch is set to ON. When this switch is set to ON. the eNodeB instructs UEs to use the non-contention-based random access mode during handovers. the eNodeB instructs UEs to use the contention-based random access mode during handovers. When this switch is set to OFF. the backoff control algorithm is enabled.LTE eRAN2. When this switch is set to OFF. When this switch is set to ON. the backoff control algorithm is disabled. the algorithm dynamically adjusts the preamble configuration based on the preamble usage. When this switch is set to OFF. the eNodeB instructs the UE to use the contention-based random access mode upon DL data arrival in the case of out-of-synchronization. LTE eRAN2. No Spreading Without Permission .1 Connection Management Feature Confidential Information of Huawei. 1 Connection Management Feature Signaling connection consists of RRC connection on the Uu interface and dedicated S1 connection. but not for the service bearer connection. Generally. No Spreading Without Permission .LTE eRAN2. however. signaling connection is established for the establishment of the service bearer connection. signaling connection is used only for the signaling procedure (such as UE location update). In certain scenarios. Confidential Information of Huawei. No Spreading Without Permission . The relations among NAS procedure.1 Connection Management Feature the UE selects a cause for RRC connection establishment according to NAS procedure. in which the UE notifies the lower layer of the purpose for the RRC connection. call type. and cause for RRC connection establishment is list below: NAS Procedure Cause for RRC Connection Establishment Attach MO-signaling Tracking area update MO-signaling Detach MO-signaling MO-data (request for radio resources for service bearer) Service request Call Type Originating signaling Originating signaling Originating signaling Originating call MO-data (request for resources for Originating uplink signaling) call Terminating MT-access (paging response) call MO-data (mobile originating CS Originating fallback) call MT-access (mobile terminating CS Terminating Extended service request fallback) call Emergency (mobile originating CS Emergency fallback emergency call) call Confidential Information of Huawei.LTE eRAN2. Confidential Information of Huawei.LTE eRAN2. the subsequent steps proceed. After the eNodeB receives the RRC Connection Setup Complete message. The eNodeB establishes the UE context after receiving the RRC Connection Request message.1. The eNodeB responds to the UE with an RRC Connection Setup message over the CCCH. the eNodeB does not need to obtain the IMSI information of the UE. The eNodeB performs the SRB1 resource admission and allocation. If resource allocation fails. the RRC connection is established.1 Connection Management Feature UE_ID is contained in the RRC Connection Request message. In the LTE system. If the upper layer does not provide the S-TMSI. the UE sends the message containing the S-TMSI to the eNodeB. the UE sends the eNodeB the message containing a random value ranging from 0 to 240 . If the upper layer provides the SAE Temporary Mobile Station Identifier (S-TMSI). All signaling connections are admitted without any judgment. and then the UE sends the eNodeB the RRC Connection Setup Complete message containing the NAS message. the eNodeB responds to the UE with an RRC Connection Reject message. If resource allocation is successful. The UE performs radio resource configuration after receiving the RRC Connection Setup message containing the SRB1 resource information. No Spreading Without Permission . The message contains detailed information about the SRB1 resource configuration. It refers to the wait time for retransmitting an RRCConnectionRequest message after the previous request with a cause other than "MO-Data" and "MO-Signalling" is rejected. No Spreading Without Permission . This timer is stopped when the UE enters the RRC_CONNECTED mode or performs cell reselection. Confidential Information of Huawei. This timer is started after the UE receives the RRC Connection Reject message.1 Connection Management Feature Parameter ID Description T302 Indicates the length of timer T302.LTE eRAN2. After receiving the Initial Context Setup Request message. The eNodeB performs service admission decision and resource allocation.by comparing the eNodeB-supported algorithms with the UEsupported algorithms.1 Connection Management Feature Dedicated S1 connection is between the eNodeB and the MME. the MME handles the UE service request based on the cause and allocates a dedicated S1APID to the UE on S1-MME interface. The MME sends the eNodeB the Initial Context Setup Request message. the eNodeB starts the UE context establishment. Confidential Information of Huawei. The dedicated S1 connection establishment procedure is as follows: After receiving the RRC Connection Setup Complete message. the eNodeB selects a security algorithm supported by both the eNodeB and the UE and then sends the algorithm to the UE through the Security Mode Command message. which may contain the common UE context and EPS bearer context. the eNodeB allocates a dedicated S1APID to the UE. No Spreading Without Permission . After receiving the RRC Connection Setup Complete message. For the security keys . the eNodeB generates security keys for service bearer and signaling based on the received security parameters. At the same time. The MME parses the NAS message contained in the Initial UE Message before obtaining the cause for the connection establishment. the eNodeB sends the MME the Initial UE Message containing the NAS message to start dedicated S1 connection establishment. Then.LTE eRAN2. the eNodeB encapsulates the NAS message that is originally contained in the RRC Connection Setup Complete message and S1APID in the Initial UE Message before forwarding the Initial UE Message to the MME. Then. After the security keys that are used by both the service bearer and the signaling are successfully generated. Confidential Information of Huawei. the UE transmits the Security Mode Complete message. At the moment of the eNodeB instruction. After receiving the Security Mode Command message from the eNodeB. The eNodeB sends the UE the RRC Connection Reconfiguration message on which encryption and integrity protection is performed. the UE responds to the eNodeB with an RRC Connection Reconfiguration Complete message. which is not encrypted. uplink encryption is started. After the resources are successfully established. The eNodeB sends the MME the feedback through the Initial Context Setup Response message. the UE selects an encryption algorithm provided by the eNodeB. After the eNodeB receives the Security Mode Complete message. No Spreading Without Permission . which indicates that the bearer is successfully established. the UE obtains security keys based on the algorithms in the message.LTE eRAN2. downlink encryption has been started. This is used for the establishment of the SRB2 and DRB. In the process. The UE establishes corresponding resources according to the RRC Connection Reconfiguration message.1 Connection Management Feature The eNodeB instructs the UE to start integrity protection and encryption through the Security Mode Command message. RRC connection reestablishment can be triggered in the case of a handover failure.LTE eRAN2. radio link failure. whereas other bearers cannot be resumed. When handling the RRC connection reestablishment. After the RRC connection is successfully reestablished. and reactivates the security in the AS without modifying the security algorithm.1 Connection Management Feature RRC connection Reestablishment involves the SRB1 reestablishment and security reactivation. Confidential Information of Huawei. If the eNodeB does not have the UE context information. A UE in RRC_CONNECTED mode. whose security is activated. a UE cannot initiate RRC connection reestablishment. A UE may be admitted for RRC connection reestablishment by a cell only if the UE requests RRC connection reestablishment in the cell that is served by an eNodeB having the UE context information. the UE will be rejected on RRC connection reestablishment. RRC reconfiguration failure. can initiate RRC connection reestablishment for resuming RRC connection. the SRB1 can be resumed. No Spreading Without Permission . resumes data transmission on the service bearer. If security in the AS is not activated. the eNodeB reconfigures the SRB1. or integrity check failure. The cause for the RRC connection reestablishment triggered by a reconfiguration failure is reconfigurationFailure.LTE eRAN2. C-RNTI and physCellId in the cause are the information of the serving cell.1 Connection Management Feature The RRC connection reestablishment procedure is as follows: The UE sends the RRC Connection Reestablishment Request message. C-RNTI and physCellId in the cause are the information of the serving cell. the eNodeB sends the UE the RRC Connection Reestablishment message. Otherwise . C-RNTI and physCellId in the cause are the information of the source cell. Confidential Information of Huawei. the UE reconfigures radio resources according to the instructions in the message and then starts encryption and integrity protection.Over the CCCH. the eNodeB rejects the RRC connection reestablishment request of the UE. which contains the information of the allocated resources. After receiving the RRC Connection Reestablishment message. The cause for the RRC connection reestablishment triggered by a handover failure is handoverFailure. No Spreading Without Permission . If the UE fails to be verified. The cause for the RRC connection reestablishment and cell information contained in the message varies according to the scenario. The cause for the RRC connection reestablishment triggered by a radio link failure is otherFailure. The UE sends the eNodeB the RRC Connection Reestablishment Complete message. Confidential Information of Huawei. the eNodeB sends a signaling link release request to the MME.LTE eRAN2. Signaling link release can be initiated by the MME or eNodeB. the MME sends the eNodeB a signaling link release command. RRC connection release consists of the release of the signaling link and all the radio bearers between the UE and the eNodeB. If service between the UE and the MME in the NAS is complete or a UE decides to stop the service. No Spreading Without Permission . If an exception is detected.1 Connection Management Feature Signaling link release involves the release of the dedicated S1 connection and RRC connection. the eNodeB does not need to wait for the response from the UE. indicating that the resource release is complete. In this case. In this case. The MME can release the dedicated S1 connection of a UE to release all the S1 resources for all the service bearers.LTE eRAN2. The eNodeB releases transmission resources and triggers the release of the RRC connection over the Uu interface. After sending the UE Context Release Complete message. the eNodeB must wait until the MME sends a UE Context Release Command message. The eNodeB monitors data transmission and reception of a UE. This typical procedure is applied after UeInactiveTimer expires. Then. The eNodeB sends the MME the UE Context Release Complete message.1 Connection Management Feature This is a signaling link release procedure after eNodeB detecting an exception： The eNodeB sends the MME a UE Context Release Request message. the UE is changed from RRC_CONNECTED mode to RRC_IDLE mode. The eNodeB sends the UE an RRC Connection Release message to release the resources over the Uu interface. Confidential Information of Huawei. After the timer expires. The eNodeB releases the radio resources in the system. the eNodeB sends the MME the signaling link release request if the UE does not receive or send any data. No Spreading Without Permission . the eNodeB releases the corresponding UE context. Confidential Information of Huawei. The eNodeB monitors whether UEs are receiving or sending data. No Spreading Without Permission . When this parameter is set to 0.1 Connection Management Feature Parameter ID Description UeInactiveTimer Indicates the time threshold that specifies when an idle UE should be disconnected from the network. the eNodeB does not monitor the data transmitting or receiving state of the UE.LTE eRAN2. the eNodeB releases the radio resources of the UE. When a UE has neither received nor sent data for a duration exceeding this threshold. LTE eRAN2.1 Connection Management Feature Confidential Information of Huawei. No Spreading Without Permission . Confidential Information of Huawei.LTE eRAN2. No Spreading Without Permission . This data radio bearer is for the default EPS bearer.1 Connection Management Feature The initial data radio bearer is setup with SRB2 in the initial UE context procedure after encryption and integrity protection completion . LTE eRAN2. According to the instructions contained in the message. the DRB establishment can be triggered by the E-RAB Setup Request message sent from the MME. drb-ToAddModList which is originally contained in the Radio Resource Config Dedicated message is contained in the RRC Connection Reconfiguration message. Confidential Information of Huawei. establishes an RLC entity and configures related parameters. the UE establishes a corresponding PDCP entity and configures the related security parameters.1 Connection Management Feature After the UE context is established. and establishes a DTCH and configures the logical channel. No Spreading Without Permission . Confidential Information of Huawei. and DTCH. No Spreading Without Permission .LTE eRAN2. According to the instructions in the RRC Connection Reconfiguration message.1 Connection Management Feature The DRB modification is triggered by the MME through the E-RAB Modify Request message. the UE reconfigures the corresponding PDCP entity. corresponding RLC entity. 1 Connection Management Feature The DRB is normally released altogether with the signaling connection. drb-ToReleaseList that is originally contained in the Radio Resource Config Dedicated message is contained in the RRC Connection Reconfiguration message. the DRB may be released by the E-RAB Release Command message sent from the MME. In some cases. Confidential Information of Huawei. Upon receiving the message. During the DRB release.LTE eRAN2. the UE releases all the corresponding DRB resources. No Spreading Without Permission . the eNodeB instructs UEs to use the noncontention-based random access mode during handovers. the eNodeB allocates a dedicated preamble to only one UE at a time. the RACH resource adjustment algorithm is disabled. the backoff control algorithm is disabled. If this switch is set to OFF. HoRaSwitch: Indicates the switch that is used to control the random access mode applied during handovers.1 Connection Management Feature Parameter description MO Parameter ID CellAlgoSwi RachAlgoSwitch tch Description RACHAdjSwitch: Indicates the switch that is used to enable and disable the RACH resource adjustment algorithm. No Spreading Without Permission . If this switch is set to ON. which is used to derive the preamble sequence. MaksIdxSwitch: Indicates whether the dedicated preamble is reused among UEs. ateTimer T302 specifies the wait time for retransmitting an RRCConnectionRequest message after the previous request with a cause other than "MO-Data" and "MO-Signalling" is rejected. If this switch is set to ON. If this switch is set to OFF. Confidential Information of Huawei. which adaptively adjusts the RACH resources in the cell based on the access type and the number of accesses.LTE eRAN2. If this switch is set to ON. the eNodeB instructs UEs to use the contentionbased random access mode during handovers. the RACH resource adjustment algorithm is enabled. Cell RootSequenceIdx Indicates the index of the logical root sequence. BackOffSwitch: Indicates the switch that is used to enable and disable the backoff control algorithm. The eNodeB monitors whether ateTimer UEs are receiving or sending data. This timer is stopped when the UE enters the RRC_CONNECTED mode or performs cell reselection. This timer is started after the UE receives the RRCConnectionReject message. If this switch is set to OFF. Cell PreambleFmt Indicates the preamble format used in the cell. the eNodeB releases the radio resources for the UE. the UE inactivity timer is not used. the eNodeB instructs UEs to use the noncontention-based random access mode upon DL data arrival in the case of out-of-synchronization. RRCConnSt T302 Indicates the length of timer T302. Each logical root sequence corresponds to a physical root sequence. the eNodeB enables reuse of a dedicated preamble among UEs based on the MaskIndex parameter. RRCConnSt UeInactiveTimer Indicates the length of the UE inactivity timer. When a UE has neither received nor sent data for a duration exceeding this period of time. If this switch is set to OFF. UnsyncRaSwitch: Indicates the switch that is used to control the random access mode applied when UEs are out of synchronization in the uplink. the eNodeB instructs the UE to use the contention-based random access mode upon DL data arrival in the case of out-of-synchronization. If this switch is set to ON. Cell CellRadius Indicates the radius of the cell. If this switch is set to ON. If this switch is set to OFF. If this parameter is set to 0. the backoff control algorithm is enabled. 1 Connection Management Feature Confidential Information of Huawei. No Spreading Without Permission .LTE eRAN2.