# Feature Set **Table of Contents** [[_TOC_]] ## Functional Split Architecture - RCC: Radio-Cloud Center - RAU: Radio-Access Unit - RRU: Remote Radio-Unit - IF4.5 / IF5 : similar to IEEE P1914.1 - FAPI (IF2) : specified by Small Cell Forum (open-nFAPI implementation) - IF1 : F1 in 3GPP Release 15  ## OpenAirInterface Block Diagram  ## OpenAirInterface 5G-NR Feature Set ### General Parameters The following features are valid for the gNB and the 5G-NR UE. * Static TDD - Multi TDD pattern supported refer [TDD Configuration](MAC/mac-usage.md) * Static FDD * Normal CP * Subcarrier spacings: 15 and 30kHz (FR1), 120kHz (FR2) * Bandwidths: 5-100MHz (FR1), 100 and 200MHz (FR2) * Intermediate downlink and uplink frequencies to interface with IF equipment * Procedures for 4-layer DL and 2-layer UL SU-MIMO * Slot format: 14 OFDM symbols in UL or DL * Highly efficient 3GPP compliant LDPC encoder and decoder (BG1 and BG2 supported) * Highly efficient 3GPP compliant polar encoder and decoder * Encoder and decoder for short blocks * Support for UL transform precoding (SC-FDMA) These modes of operation are supported: * "phy-test" mode (gNB, nrUE): - gNB and nrUE have hardcoded RNTI and radio configuration - gNB schedules the nrUE all the time, even if no UE connected - can be used for performance evaluation * "noS1" mode (DL and UL, gNB, nrUE): - Connection setup stops after RA; RRC configuration is exchanged through files - Creates TUN interface to SDAP to inject and receive user-place traffic - No connection to the core network * Standalone (SA) mode (gNB, nrUE): - UE can register with the 5G Core Network through the gNB, establish a PDU Session and exchange user-plane traffic - Reestablishment supported * Non-standalone (NSA) mode (gNB): - UE can use the gNB for user plane traffic while connected to the 4G eNB - is unstable (only one UE connection) ### gNB PHY * 15kHz and 30kHz SCS for FR1 and 120kHz SCS for FR2 * Generation of NR-PSS/NR-SSS * NR-PBCH supports multiple SSBs and flexible periodicity * Generation of NR-PDCCH (including generation of DCI, polar encoding, scrambling, modulation, RB mapping, etc) - common search space - user-specific search space - DCI formats: 00, 10, 01 and 11 * Generation of NR-PDSCH (including Segmentation, LDPC encoding, rate matching, scrambling, modulation, RB mapping, etc). - PDSCH mapping type A and B - DMRS configuration type 1 and 2 - Single and multiple DMRS symbols - PTRS support - Support for up to 4 TX antennas - Support for up to 4 layers - Support for 256 QAM * NR-CSIRS Generation of sequence at PHY * NR-PUSCH (including Segmentation, LDPC encoding, rate matching, scrambling, modulation, RB mapping, etc). - PUSCH mapping type A and B - DMRS configuration type 1 and 2 - Single and multiple DMRS symbols - PTRS support - Support for up to 4 RX antennas - Support for up to 2 layers - Support for 256 QAM * NR-PUCCH - Format 0 (2 bits, for ACK/NACK and SR) - Format 2 (mainly for CSI feedback) * NR-SRS - SRS signal reception - Channel estimation (with T tracer real time monitoring) - Power noise estimation * NR-PRS - Rel16 Positioning reference signal(PRS) generation and modulation - Multiple PRS resources, one per beam is supported in FR2 TDD mode - FR1 and FR2 support with config file * NR-PRACH - Formats 0,1,2,3, A1-A3, B1-B3 * Highly efficient 3GPP compliant LDPC encoder and decoder (BG1 and BG2 are supported) * Highly efficient 3GPP compliant polar encoder and decoder * Encoder and decoder for short block ### gNB MAC - MAC -> PHY configuration using NR FAPI P5 interface - MAC <-> PHY data interface using FAPI P7 interface for DL_TTI.request, UL_TTI.request, UL_DCI.request, TX_data.request, RX_Data.indication, CRC.indication, UCI.indication, SRS.indication - Generation of and scheduler procedures for MIB/SIB1 - Scheduler procedures for RA - 4-Step RA - Contention Free RA procedure - Contention Based RA procedure - Msg3 can transfer uplink CCCH, DTCH or DCCH messages - CBRA can be performed using MAC CE for C-RNTI - Is not possible to use 2-Step RA and 4-Step RA at the same time - 2-Step RA - Contention Based RA procedure - MsgA can transfer uplink CCCH, DTCH or DCCH messages - CBRA can be performed using MAC CE for C-RNTI - Is not possible to use 2-Step RA and 4-Step RA at the same time - Fallback not supported - Scheduler procedures for CSI-RS - MAC downlink scheduler - phy-test scheduler (fixed allocation and usable also without UE) - regular scheduler with dynamic proportionally-fair allocation - MCS adaptation from HARQ BLER or SSB-SINR report - MAC header generation (including timing advance) - ACK/NACK handling and HARQ procedures for downlink - MAC uplink scheduler - phy-test scheduler (fixed allocation) - regular scheduler with dynamic proportionally-fair allocation - HARQ procedures for uplink - MCS adaption from HARQ BLER or PUSCH SINR - Scheduler procedures for SRS reception - Periodic SRS reception - Channel rank computation up to 2x2 scenario - TPMI computation based on SRS up 4 antenna ports and 2 layers - MAC procedures to handle CSI measurement report - evalution of RSRP report - evaluation of CQI report - MAC scheduling of SR reception - Intra-frequency handover - Inter-frequency handover - Measurement gaps are automatically computed at the DU if the CU has neighbor information and the configured neighbors include cells operating on different frequencies - DUs must be synchronized with each other for the measurements to be properly performed - Initial support for RedCap - RedCap SIB1 v17 IEs supported - Coexistence of RedCap and Normal UEs - Handling of RedCap capability for small PDCP/RLC SN size - Scheduling of other SIBs (2, 3, 4, 19) - NTN - Support downlinkHARQ-FeedbackDisabled-r17 - Support for 32 PDSCH and PUSCH HARQ processes per UE - Consider ntn-Config-r17.cellSpecificKoffset-r17 in scheduling - Function-based interface for ntn-Config-r17 updates (used by NTN-LEO RFsimulator) ### gNB RLC - Send/Receive operations according to 38.322 Rel.16 - Segmentation and reassembly procedures - RLC Acknowledged mode supporting PDU retransmissions - RLC Unacknowledged mode - DRBs and SRBs establishment/handling and association with RLC entities - Timers implementation - Interfaces with PDCP, MAC - Interfaces with gtp-u (data Tx/Rx over F1-U at the DU) ### gNB PDCP - Send/Receive operations according to 38.323 Rel.16 - Integrity protection and ciphering procedures - Sequence number management, SDU dicard and in-order delivery - Radio bearer establishment/handling and association with PDCP entities - Interfaces with RRC, RLC - Interfaces with gtp-u (data Tx/Rx over N3 and F1-U interfaces) ### gNB SDAP - Send/Receive operations according to 37.324 Rel.15 - Establishment/Handling of SDAP entities. - Transfer of User Plane Data - Mapping between a QoS flow and a DRB for both DL and UL - Marking QoS flow ID in both DL and UL packets - Reflective QoS flow to DRB mapping for UL SDAP data PDUs ### gNB RRC - NR RRC (38.331) Rel 17 messages using new [asn1c](https://github.com/mouse07410/asn1c) - LTE RRC (36.331) also updated to Rel 15 - Generation of system information (SIB2, SIB3, SIB4) - RRC can configure PDCP and SDAP (through E1), and RLC and MAC (through F1) - Interface with GTP-U (tunnel creation/handling for S1-U (NSA), N3 (SA), F1 interfaces) - Integration of RRC messages and procedures supporting UE 5G SA connection - RRCSetupRequest/RRCSetup/RRCSetupComplete - RRC Uplink/Downlink Information transfer carrying NAS messages transparently - RRC Reconfiguration/Reconfiguration complete - RRC Reestablishment/Reestablishment complete - Support for MasterCellGroup configuration (from DU) - Interface with NGAP for the interactions with the AMF - Interface with F1AP for CU/DU split deployment option - Interface with E1AP for CU-CP/CU-CP split deployment option - Periodic RRC measurements of serving/neighbour cells and A2/A3 event handling - RRC Mobility Management Procedures: - Inter-DU Handover (F1-based handover within same CU) - Inter-gNB Handover (N2-based handover between different gNBs) - Handover Preparation Information generation and processing - Handover Command generation and processing - PDCP Status transfer procedures - Support for handover decision triggers (A3 events, manual triggers) - Initial support for RedCap (see MAC) ### gNB X2AP - Integration of X2AP messages and procedures for the exchanges with the eNB over X2 interface supporting the NSA setup according to 36.423 Rel. 15 - X2 setup with eNB - Handling of SgNB Addition Request/Addition Request Acknowledge/Reconfiguration Complete ### gNB NGAP - Integration of NGAP messages and procedures for the exchanges with the AMF over N2 interface according to 38.413 Rel. 15 - NGAP Setup request/response - NGAP Initial UE message - NGAP Initial context setup request/response - NGAP Downlink/Uplink NAS transfer - NGAP UE context release request/complete - NGAP UE radio capability info indication - NGAP PDU session resource setup request/response - NGAP Mobility Management Procedures: * NGAP Handover Required * NGAP Handover Request * NGAP Handover Request Acknowledge * NGAP Handover Command * NGAP Handover Notify * NGAP Handover Cancel * NGAP Handover Cancel Acknowledge * NGAP Uplink RAN Status Transfer * NGAP Downlink RAN Status Transfer - Interface with RRC ### gNB F1AP - Integration of F1AP messages and procedures for the control plane exchanges between the CU and DU entities according to 38.473 Rel. 16 - F1 Interface Management: * F1 Setup request/response/failure - F1 RRC Message Transfer: * F1 Initial UL RRC Message Transfer * F1 DL RRC Message Transfer * F1 UL RRC Message Transfer - F1 UE Context Management: * F1 UE Context setup request/response * F1 UE Context modification request/response * F1 UE Context modification required * F1 UE Context release req/cmd/complete - F1 gNB CU configuration update - F1 gNB DU configuration update - F1 Reset (handled at DU only, full reset only) - F1 Mobility Management Procedures: * F1 Intra-CU Handover (Inter-DU mobility) - Interface with RRC - Interface with GTP-u (tunnel creation/handling for F1-U interface) - One CU(-CP) can handle multiple DUs - Support for intra-CU mobility (across DUs) ### gNB E1AP - Integration of E1AP messages and procedures for exchange between CU-CP and CU-UP according to TS 38.463 Rel. 16 - E1 Setup (gNB-CU-UP initiated) - E1 Setup Request - E1 Setup Response - E1 Setup Failure - E1 Bearer Context Setup (gNB-CU-CP initiated) - E1 Bearer Context Setup Request - E1 Bearer Context Setup Response - Bearer Context Modification (gNB-CU-CP initiated) - E1 Bearer Context Modification Request - E1 Bearer Context Modification Response - E1 Reset - Interface with RRC and PDCP/SDAP - One CU-CP can handle multiple CU-UPs ### gNB GTP-U - New GTP-U implementation supporting both N3 and F1-U interfaces according to 29.281 Rel.15 - Interfaces with RRC, F1AP for tunnel creation - Interfaces with PDCP and RLC for data send/receive at the CU and DU respectively (F1-U interface) - Interface with SDAP for data send/receive, capture of GTP-U Optional Header, GTP-U Extension Header and PDU Session Container. ### Number of supported UEs * 16 by default (as defined in `MAX_MOBILES_PER_GNB`) * up to 64 if the configured bandwidth is sufficient (at leat 40 MHz) ## OpenAirInterface 5G-NR UE Feature Set ### NR UE PHY Layer * Initial synchronization - non-blind synchronization (information required: carrier frequency, bandwidth, numerology) - option to search SSB inside the bandwidth available * Time tracking based on PBCH DMRS * Initial Frequency offset estimation based on PSS and SSS * Continuous Frequency offset estimation and compensation based on PBCH DMRS * 15kHz and 30kHz SCS for FR1 and 120 kHz SCS for FR2 * Reception of NR-PSS/NR-SSS * NR-PBCH supports multiple SSBs and flexible periodicity - RSRP measurement for the strongest SSB - RSRP measurement for neighboring cell at same SSB frequency with serving cell * Reception of NR-PDCCH (including reception of DCI, polar decoding, de-scrambling, de-modulation, RB de-mapping, etc) - common search space configured by MIB - user-specific search space configured by RRC - DCI formats: 00, 10, 01 and 11 * Reception of NR-PDSCH (including Segmentation, LDPC decoding, rate de-matching, de-scrambling, de-modulation, RB de-mapping, etc). - PDSCH mapping type A and B - Downlink resource allocation type 0 and 1 - DMRS configuration type 1 and 2 - Single and multiple DMRS symbols - PTRS support - Support for 256 QAM - Support for 1, 2 and 4 RX antennas - Support for up to 2 layers (currently limited to DMRS configuration type 2) * Measurements based on NR-CSIRS - RSRP measurements - RI, PMI and CQI computation - Support for up to 4 RX antennas - Support for up to 2 layers * NR-PUSCH (including Segmentation, LDPC encoding, rate matching, scrambling, modulation, RB mapping, etc). - PUSCH mapping type A and B - DMRS configuration type 1 and 2 - Single and multiple DMRS symbols - PTRS support - Support for 256 QAM - Support for up to 2 TX antenna - Support for up to 2 layers - Support for UCI on PUSCH * NR-PUCCH - Format 0 (2 bits for ACK/NACK and SR) - Format 2 (mainly for CSI feedback) - Format 1 (limited testing) - Format 3 and 4 present but old code never tested (need restructuring before verification) * NR-SRS - Generation of sequence at PHY - SRS signal transmission * NR-PRS - PRS based Channel estimation with T tracer dumps - Time of arrival(ToA) estimation based on channel impulse response(CIR) - Finer ToA estimation by 16x oversampled IDFT for CIR - Support for multiple gNB reception with gNBs synced via GPSDO * NR-PRACH - Formats 0,1,2,3, A1-A3, B1-B3 * NTN - TA adjustemt based on ntn-Config-r17 information - Different TA adjustemt algorithms between SIB19 receptions: - Autonomous TA adjustemt based on DL time tracking - Standard compliant epoch time based TA adjustment including orbital propagation - DL Doppler compensation based on ntn-Config-r17 information - UL Doppler pre-compensation based on ntn-Config-r17 information and residual DL FO estimation * Highly efficient 3GPP compliant LDPC encoder and decoder (BG1 and BG2 are supported) * Highly efficient 3GPP compliant polar encoder and decoder * Encoder and decoder for short block ### NR UE FAPI * MAC -> PHY configuration via UE FAPI P5 interface * Basic MAC to control PHY via UE FAPI P7 interface * PHY -> MAC indication ### NR UE Higher Layers ### UE MAC * Minimum system information (MSI) - MIB processing - Scheduling of system information block 1 (SIB1) reception * Other system information - Scheduling of other system information blocks reception (SIB2, SIB3, SIB4) * Random access procedure (needs improvement, there is still not a clear separation between MAC and PHY) - Mapping SSBs to multiple ROs - Scheduling of PRACH - 4-Step RA - Processing of RAR - Transmission and re-transmission of Msg3 - Msg4 and contention resolution - 2-Step RA - Transmission of MsgA-PUSCH - Reception of MsgB - Processing of SuccessRAR - Fallback not supported * DCI processing - format 10 (RA-RNTI, C-RNTI, SI-RNTI, TC-RNTI) - format 00 (C-RNTI, TC-RNTI) - format 11 (C-RNTI) - format 01 (C-RNTI) * UCI processing - ACK/NACK processing - Scheduling request procedures - CSI measurement reporting (periodic and aperiodic) * DLSCH scheduler - Configuration of fapi PDU according to DCI - HARQ procedures * ULSCH scheduler - Configuration of fapi PDU according to DCI - Buffer status reporting procedures - Logical channel prioritization of 'data from any logical channel' - UCI on PUSCH * NR-CSIRS scheduler - Scheduling of NR-CSIRS reception - Fill UCI for CSI measurement reporting * Scheduler procedures for SRS transmission - Periodic and aperiodic SRS transmission * Bandwidth part (BWP) operation - Operation in configured dedicated BWP through RRCSetup or RRCReconfiguration * NTN - Support downlinkHARQ-FeedbackDisabled-r17 - Support for 32 PDSCH and PUSCH HARQ processes - Consider ntn-Config-r17.cellSpecificKoffset-r17 in scheduling ### UE RLC * Tx/Rx operations according to 38.322 Rel.16 - Segmentation and reassembly procedures - RLC Acknowledged mode supporting PDU retransmissions - RLC Unacknowledged mode - DRBs and SRBs establishment and handling - Timers implementation - Interfaces with PDCP, MAC ### UE PDCP * Tx/Rx operations according to 38.323 Rel.16 - Integrity protection and ciphering procedures - Sequence number management, SDU dicard and in-order delivery - Radio bearer establishment/handling and association with PDCP entities - Interfaces with RRC, RLC ### UE SDAP * Tx/Rx operations operations according to 37.324 Rel.15 - Establishment/Handling of SDAP entities. - Transfer of User Plane Data - Reflective Mapping - RRC Signaling Mapping ### UE RRC * Integration of RRC messages and procedures supporting UE 5G SA connection according to 38.331 Rel.16 - RRCSetupRequest/RRCSetup/RRCSetupComplete - RRCReject - RRCRelease/ RRC going to IDLE - RRC Uplink/Downlink Information transfer carrying NAS messages transparently - RRC Reconfiguration/Reconfiguration complete - RRCSetup fallback (after reestablishment) - RRCReestablishmentRequest/RRC Reestablishment/Reestablishment complete - Support for master cell group configuration - Reception of UECapabilityEnquiry, encoding and transmission of UECapability - Support for measurement report of Event A2/A3 * NTN according to 38.331 Rel.17 - Reception of ntn-Config-r17 from SIB19 or reconfigurationWithSync - Handling of ntn-UlSyncValidityDuration-r17 in SIB19 * Interface with PDCP: configuration, DCCH and CCCH message handling * Interface with RLC and MAC for configuration ### UE 5G NAS * Transfer of NAS messages between the AMF and the UE supporting the UE registration with the core network and the PDU session establishment according to 24.501 Rel.16 * 5GMM (5G Mobility Management) messages: - Service Request/Accept/Reject (enc/dec library only) - Identity Request/Response - Authentication Request/Response - Security Mode Command/Complete - Registration Request/Accept/Complete - Deregistration Request (UE originating) - Uplink NAS Transport * 5GSM (5G Session Management) messages: - PDU Session Establishment Request/Accept * Security Features: - NAS message integrity protection and ciphering - Security context establishment and management * Integration: - NAS configuration and interfacing with RRC - Integration with SDAP for user plane data transfer For detailed implementation status, encoding/decoding support, and unit test coverage, see [5G NAS Implementation Documentation](5Gnas.md). ## OpenAirInterface 4G LTE eNB Feature Set ### eNB PHY Layer The Physical layer implements **3GPP 36.211**, **36.212**, **36.213** and provides the following features: - LTE release 8.6 compliant, and implements a subset of release 10 - FDD and TDD configurations: 1 (experimental) and 3 - Bandwidth: 5, 10, and 20 MHz - Transmission modes: 1, 2 (stable), 3, 4, 5, 6, 7 (experimental) - Max number of antennas: 2 - CQI/PMI reporting: aperiodic, feedback mode 3 - 0 and 3 - 1 - PRACH preamble format 0 - Downlink (DL) channels are supported: PSS, SSS, PBCH, PCFICH, PHICH, PDCCH, PDSCH, PMCH, MPDCCH - Uplink (UL) channels are supported: PRACH, PUSCH, PUCCH (format 1/1a/1b), SRS, DRS - HARQ support (UL and DL) - Highly optimized base band processing (including turbo decoder) - Multi-RRU support: over the air synchro b/ multi RRU in TDD mode - Support for CE-modeA for LTE-M. Limited support for repeatition, single-LTE-M connection, legacy-LTE UE attach is disabled. #### Performances **Transmission Mode, Bandwidth** | **Expected Throughput** | **Measured Throughput** | **Measurement Conditions** -------------------------------- | ----------------------- | ------------------------| ----------------: FDD DL: 5 MHz, 25 PRBS/ MCS 28 | 16 - 17 Mbit/s | TM1: 17.0 Mbits/s | COTS-UE Cat 4 (150/50 Mbps) FDD DL: 10 MHz, 50 PRBS/ MCS 28 | 34 - 35 Mbit/s | TM1: 34.0 Mbits/s | COTS-UE Cat 4 (150/50 Mbps) FDD DL: 20 MHz, 100 PRBS/ MCS 28 | 70 Mbit/s | TM1: 69.9 Mbits/s | COTS-UE Cat 4 (150/50 Mbps) | | | FDD UL: 5 MHz, 25 PRBS/ MCS 20 | 9 Mbit/s | TM1: 8.28 Mbits/s | COTS-UE Cat 4 (150/50 Mbps) FDD UL: 10 MHz, 50 PRBS/ MCS 20 | 17 Mbit/s | TM1: 18.3 Mbits/s | COTS-UE Cat 4 (150/50 Mbps) FDD UL: 20 MHz, 100 PRBS/ MCS 20 | 35 Mbit/s | TM1: 18.6 Mbits/s | COTS-UE Cat 4 (150/50 Mbps) | | TDD DL: 5 MHz, 25 PRBS/ MCS **XX** | 6.5 Mbit/s | TM1: 6.71 Mbits/s | COTS-UE Cat 4 (150/50 Mbps) TDD DL: 10 MHz, 50 PRBS/ MCS **XX** | 13.5 Mbit/s | TM1: 13.6 Mbits/s | COTS-UE Cat 4 (150/50 Mbps) TDD DL: 20 MHz, 100 PRBS/ MCS **XX** | 28.0 Mbit/s | TM1: 27.2 Mbits/s | COTS-UE Cat 4 (150/50 Mbps) | | | TDD UL: 5 MHz, 25 PRBS/ MCS **XX** | 2.0 Mbit/s | TM1: 3.31 Mbits/s | COTS-UE Cat 4 (150/50 Mbps) TDD UL: 10 MHz, 50 PRBS/ MCS **XX** | 2.0 Mbit/s | TM1: 7.25 Mbits/s | COTS-UE Cat 4 (150/50 Mbps) TDD UL: 20 MHz, 100 PRBS/ MCS **XX** | 3.0 Mbit/s | TM1: 4.21 Mbits/s | COTS-UE Cat 4 (150/50 Mbps) #### Number of supported UEs * 16 by default * up to 256 when compiling with dedicated compile flag * was tested with 40 COTS-UE ### eNB MAC Layer The MAC layer implements a subset of the **3GPP 36.321** release v8.6 in support of BCH, DLSCH, RACH, and ULSCH channels. - RRC interface for CCCH, DCCH, and DTCH - Proportional fair scheduler (round robin scheduler soon), with the following improvements: - Up to 30 users tested in the L2 simulator, CCE allocation in the preprocessor ; the scheduler was also simplified and made more modular - Adaptative UL-HARQ - Remove out-of-sync UEs - No use of the `first_rb` in the UL scheduler ; respects `vrb_map_UL` and `vrb_map` in the DL - DCI generation - HARQ Support - RA procedures and RNTI management - RLC interface (AM, UM) - UL power control - Link adaptation - Connected DRX (CDRX) support for FDD LTE UE. Compatible with R13 from 3GPP. Support for Cat-M1 UE comming soon. ### eNB RLC Layer The RLC layer implements a full specification of the 3GPP 36.322 release v9.3. - RLC TM (mainly used for BCCH and CCCH) * Neither segment nor concatenate RLC SDUs * Do not include a RLC header in the RLC PDU * Delivery of received RLC PDUs to upper layers - RLC UM (mainly used for DTCH) * Segment or concatenate RLC SDUs according to the TB size selected by MAC * Include a RLC header in the RLC PDU * Duplication detection * PDU reordering and reassembly - RLC AM, compatible with 9.3 * Segmentation, re-segmentation, concatenation, and reassembly * Padding * Data transfer to the user * RLC PDU retransmission in support of error control and correction * Generation of data/control PDUs ### eNB PDCP Layer The current PDCP layer is header compliant with **3GPP 36.323** Rel 10.1.0 and implements the following functions: - User and control data transfer - Sequence number management - RB association with PDCP entity - PDCP entity association with one or two RLC entities - Integrity check and encryption using the AES and Snow3G algorithms ### eNB RRC Layer The RRC layer is based on **3GPP 36.331** v15.6 and implements the following functions: - System Information broadcast (SIB 1, 2, 3, and 13) * SIB1: Up to 6 PLMN IDs broadcast - RRC connection establishment - RRC connection reconfiguration (addition and removal of radio bearers, connection release) - RRC connection release - RRC connection re-establishment - Inter-frequency measurement collection and reporting (experimental) - eMBMS for multicast and broadcast (experimental) - Handover (experimental) - Paging (soon) - RRC inactivity timer (release of UE after a period of data inactivity) ### eNB X2AP The X2AP layer is based on **3GPP 36.423** v14.6.0 and implements the following functions: - X2 Setup Request - X2 Setup Response - X2 Setup Failure - Handover Request - Handover Request Acknowledge - UE Context Release - X2 timers (t_reloc_prep, tx2_reloc_overall) - Handover Cancel - X2-U interface implemented - EN-DC is implemented - X2AP : Handling of SgNB Addition Request / Addition Request Acknowledge / Reconfiguration Complete - RRC : Handling of RRC Connection Reconfiguration with 5G cell info, configuration of 5G-NR measurements - S1AP : Handling of E-RAB Modification Indication / Confirmation ### eNB/MCE M2AP The M2AP layer is based on **3GPP 36.443** v14.0.1: - M2 Setup Request - M2 Setup Response - M2 Setup Failure - M2 Scheduling Information - M2 Scheduling Information Response - M2 Session Start Request - M2 Session Start Response ### MCE/MME M3AP The M3AP layer is based on **3GPP 36.444** v14.0.1: - M3 Setup Request - M3 Setup Response - M3 Setup Failure - M3 Session Start Request - M3 Session Start Response ## OpenAirInterface 4G LTE UE Feature Set ### LTE UE PHY Layer The Physical layer implements **3GPP 36.211**, **36.212**, **36.213** and provides the following features: - LTE release 8.6 compliant, and implements a subset of release 10 - FDD and TDD configurations: 1 (experimental) and 3 - Bandwidth: 5, 10, and 20 MHz - Transmission modes: 1, 2 (stable) - Max number of antennas: 2 - CQI/PMI reporting: aperiodic, feedback mode 3 - 0 and 3 - 1 - PRACH preamble format 0 - All downlink (DL) channels are supported: PSS, SSS, PBCH, PCFICH, PHICH, PDCCH, PDSCH, PMCH - All uplink (UL) channels are supported: PRACH, PUSCH, PUCCH (format 1/1a/1b), SRS, DRS - LTE MBMS-dedicated cell (feMBMS) procedures subset for LTE release 14 (experimental) - LTE non-MBSFN subframe (feMBMS) Carrier Adquistion Subframe-CAS procedures (PSS/SSS/PBCH/PDSH) (experimental) - LTE MBSFN MBSFN subframe channel (feMBMS): PMCH (CS@1.25KHz) (channel estimation for 25MHz bandwidth) (experimental) ### LTE UE MAC Layer The MAC layer implements a subset of the **3GPP 36.321** release v8.6 in support of BCH, DLSCH, RACH, and ULSCH channels. - RRC interface for CCCH, DCCH, and DTCH - HARQ Support - RA procedures and RNTI management - RLC interface (AM, UM) - UL power control - Link adaptation - MBMS-dedicated cell (feMBMS) RRC interface for BCCH - eMBMS and MBMS-dedicated cell (feMBMS) RRC interface for MCCH, MTCH ### LTE UE RLC Layer The RLC layer implements a full specification of the 3GPP 36.322 release v9.3. ### LTE UE PDCP Layer The current PDCP layer is header compliant with **3GPP 36.323** Rel 10.1.0. ### LTE UE RRC Layer The RRC layer is based on **3GPP 36.331** v14.3.0 and implements the following functions: - System Information decoding - RRC connection establishment - MBMS-dedicated cell (feMBMS) SI-MBMS/SIB1-MBMS management ### LTE UE NAS Layer The NAS layer is based on **3GPP 24.301** and implements the following functions: - EMM attach/detach, authentication, tracking area update, and more - ESM default/dedicated bearer, PDN connectivity, and more [OAI wiki home](https://gitlab.eurecom.fr/oai/openairinterface5g/wikis/home) [OAI softmodem build procedure](BUILD.md) [Running the OAI softmodem ](RUNMODEM.md)