FEATURE_SET.md

Table of Contents

1. Functional Split Architecture
2. OpenAirInterface Block Diagram
3. OpenAirInterface 4G-LTE eNB Feature Set
   1. eNB PHY Layer
   2. eNB MAC Layer
   3. eNB RLC Layer
   4. eNB PDCP Layer
   5. eNB RRC Layer
   6. eNB X2AP
   7. eNB/MCE M2AP
   8. MCE/MME M3AP
4. OpenAirInterface 4G-LTE UE Feature Set
   1. LTE UE PHY Layer
   2. LTE UE MAC Layer
   3. LTE UE RLC Layer
   4. LTE UE PDCP Layer
   5. LTE UE RRC Layer
5. OpenAirInterface 5G-NR gNB Feature Set
   1. General Parameters
   2. gNB Physical Layer
   3. gNB Higher Layers
6. OpenAirInterface 5G-NR UE Feature Set
   1. UE Physical Layer
   2. 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)