FEATURE_SET.md



Table of Contents

Functional Split Architecture
OpenAirInterface Block Diagram

OpenAirInterface 4G-LTE eNB Feature Set

eNB PHY Layer
eNB MAC Layer
eNB RLC Layer
eNB PDCP Layer
eNB RRC Layer
eNB X2AP
eNB/MCE M2AP
MCE/MME M3AP


OpenAirInterface 4G-LTE UE Feature Set

LTE UE PHY Layer
LTE UE MAC Layer
LTE UE RLC Layer
LTE UE PDCP Layer
LTE UE RRC Layer


OpenAirInterface 5G-NR gNB Feature Set

General Parameters
gNB Physical Layer
gNB Higher Layers


OpenAirInterface 5G-NR UE Feature Set

UE Physical Layer
UE Higher Layers


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 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


OpenAirInterface 5G-NR Feature Set

General Parameters
The following features are valid for the gNB and the 5G-NR UE.

Static TDD,
FDD
Normal CP
30 kHz subcarrier spacing
Bandwidths: 10, 20, 40, 80, 100MHz (273 Physical Resource Blocks)
Intermediate downlink and uplink frequencies to interface with IF equipment
Single antenna port (single beam)
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)


gNB PHY Layer

30KHz SCS for FR1 and 120 KHz 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 1, 2 and 4 TX antennas
Support for up to 2 layers (currently limited to DMRS configuration type 2)


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 1 RX antenna
Support for 1 layer


NR-PUCCH

Format 0 (2 bits, for ACK/NACK and SR)
Format 2 (up to 11 bits, mainly for CSI feedback)


NR-SRS

SRS signal reception
Channel estimation (with T tracer real time monitoring)
Power noise estimation


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 Higher Layers
gNB MAC

MAC -> PHY configuration using NR FAPI P5 interface
MAC <-> PHY data interface using FAPI P7 interface for BCH PDU, DCI PDU, PDSCH PDU
Scheduler procedures for SIB1
Scheduler procedures for 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 or C-RNTI


Scheduler procedures for CSI-RS
MAC downlink scheduler

phy-test scheduler (fixed allocation and usable also without UE)
regular scheduler with dynamic allocation
MCS adaptation from HARQ BLER


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 allocation
HARQ procedures for uplink


Scheduler procedures for SRS reception

Periodic SRS reception


MAC procedures to handle CSI measurement report

evalution of RSRP report
evaluation of CQI report


MAC scheduling of SR reception
Bandwidth part (BWP) operation

Handle multiple dedicated BWPs
BWP switching through RRCReconfiguration method


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 16 messages using new asn1c
LTE RRC (36.331) also updated to Rel 15
Generation of CellGroupConfig (for eNB) and MIB
Generation of system information block 1 (SIB1)
Generation of system information block 2 (SIB2)
Application to read configuration file and program gNB RRC
RRC can configure PDCP, RLC, MAC
Interface with gtp-u (tunnel creation/handling for S1-U (NSA), N3 (SA) 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
Support for master cell group configuration
Interface with NGAP for the interactions with the AMF
Interface with F1AP for CU/DU split deployment option


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


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 Setup request/response
F1 DL/UL RRC message transfer
F1 Initial UL RRC message transfer
F1 UE Context setup request/response
F1 gNB CU configuration update


Interface with RRC
Interface with gtp-u (tunnel creation/handling for F1-U interface)

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.


OpenAirInterface 5G-NR UE Feature Set

Supporting "noS1" mode (DL and UL):

Creates TUN interface to PDCP to inject and receive user-place traffic
No connection to the core network


Supporting Standalone (SA) mode:

UE can register with the 5G Core Network, establish a PDU Session and exchange user-plane traffic


NR UE PHY Layer

Initial synchronization
Time tracking based on PBCH DMRS
Frequency offset estimation
30KHz SCS for FR1 and 120 KHz SCS for FR2
Reception of NR-PSS/NR-SSS
NR-PBCH supports multiple SSBs and flexible periodicity
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
DMRS configuration type 1 and 2
Single and multiple DMRS symbols
PTRS support
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

RI, PMI and CQI computation
Support for 1 and 2 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 1 TX antenna
Support for 1 layer


NR-PUCCH

Format 0 (2 bits for ACK/NACK and SR)
Format 2 (up to 64 bits, mainly for CSI feedback)
Format 1, 3 and 4 present but old code never dested (need restructuring before verification)


NR-SRS

Generation of sequence at PHY
SRS signal transmission


NR-PRACH

Formats 0,1,2,3, A1-A3, B1-B3


SS-RSRP

RSRP measured on synchronization SSB (ok only for single SSB)


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 (needs some improvement)


NR UE Higher Layers
UE MAC

Minimum system information (MSI)

MIB processing
Scheduling of system information block 1 (SIB1) reception


Random access procedure (needs improvement, there is still not a clear separation between MAC and PHY)

Mapping SSBs to multiple ROs
Scheduling of PRACH
Processing of RAR
Transmission and re-transmission of Msg3
Msg4 and contention resolution


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
Triggering periodic SR
CSI measurement reporting


DLSCH scheduler

Configuration of fapi PDU according to DCI
HARQ procedures


ULSCH scheduler

Configuration of fapi PDU according to DCI


NR-CSIRS scheduler

Scheduling of NR-CSIRS reception
Fill UCI for CSI measurement reporting


Scheduler procedures for SRS transmission

Periodic SRS transmission


Bandwidth part (BWP) operation

Operation in configured dedicated BWP through RRCSetup or RRCReconfiguration


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
RRC Uplink/Downlink Information transfer carrying NAS messages transparently
RRC Reconfiguration/Reconfiguration complete
Support for master cell group configuration


Interface with PDCP: configuration, DCCH and CCCH message handling
Interface with RLC and MAC for configuration

UE 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

Identity Request/Response
Authentication Request/Response
Security Mode Command/Complete
Registration Request/Accept/Complete
PDU Session Establishment Request/Accept
NAS configuration and basic interfacing with RRC


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