Doc: initial commit of feature set document

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

doc/FEATURE_SET.md

+**Table of Contents**
+
+1. [OpenAirInterface eNB Feature Set](#openairinterface-enb-feature-set)
+   1. [eNB PHY Layer](#enb-phy-layer)
+   2. [eNB MAC Layer](#enb-mac-layer)
+   3. [eNB RLC Layer](#enb-rlc-layer)
+   4. [eNB PDCP Layer](#enb-pdcp-layer)
+   5. [eNB RRC Layer](#enb-rrc-layer)
+   6. [eNB X2AP](#enb-x2ap)
+   7. [eNB Advanced](#enb-advanced)
+2. [OpenAirInterface UE Feature Set](#openairinterface-ue-feature-set)
+
+# OpenAirInterface Block diagram #
+
+![Block Diagram](./oai_enb_block_diagram.png)
+
+# OpenAirInterface 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
+- 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
+- HARQ support (UL and DL)
+- Highly optimized base band processing (including turbo decoder)
+
+### Performances ###
+
+**Transmission Mode, Bandwidth** | **Expected Throughput** | **Conditions**
+-------------------------------- | ----------------------- | ----------------:
+FDD DL: 5 MHz, 25 PRBS/ MCS 28   | 16 - 17 Mbit/s          | measured with COTS UE Cat 3/4
+FDD DL: 10 MHz, 50 PRBS/ MCS 28  | 34 - 35 Mbit/s          | measured with COTS UE Cat 3/4
+FDD DL: 20 MHz, 100 PRBS/ MCS 28 | 70 Mbit/s               | measured with COTS UE Cat 3/4
+ |  | 
+FDD UL: 5 MHz, 25 PRBS/ MCS 20   | 9 Mbit/s                | measured with COTS UE Cat 3/4
+FDD UL: 10 MHz, 50 PRBS/ MCS 20  | 17 Mbit/s               | measured with COTS UE Cat 3/4
+FDD UL: 20 MHz, 100 PRBS/ MCS 20 | 35 Mbit/s               | measured with COTS UE Cat 3/4
+ |  | 
+TDD DL: 5 MHz, 25 PRBS/ MCS **XX**   | **TBC** Mbit/s | 
+TDD DL: 10 MHz, 50 PRBS/ MCS **XX**  | **TBC** Mbit/s | 
+TDD DL: 20 MHz, 100 PRBS/ MCS **XX** | **TBC** Mbit/s | 
+ |  | 
+TDD UL: 5 MHz, 25 PRBS/ MCS **XX**   | **TBC** Mbit/s | 
+TDD UL: 10 MHz, 50 PRBS/ MCS **XX**  | **TBC** Mbit/s | 
+TDD UL: 20 MHz, 100 PRBS/ MCS **XX** | **TBC** Mbit/s | 
+
+- Number of supported UEs: **To Be Completed**
+
+## 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)
+- DCI generation
+- HARQ Support
+- RA procedures and RNTI management
+- RLC interface (AM, UM)
+- UL power control
+- Link adaptation
+
+## 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** v14.3.0 and implements the following functions:
+
+- System Information broadcast (SIB 1, 2, 3, and 13)
+- 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)
+
+## eNB X2AP ##
+
+**To be completed**
+
+## Advanced Features ##
+
+**To be completed**
+
+# OpenAirInterface UE Feature Set #
+
+**To be completed**
+