AutoBuild.md

+# Building OAI executables (Trunk and next release)
+
+Please use these instructions to build OAI on the current trunk and as of Release 0.3.
+
+OAI comes with an automated build script (beta version) located at the root of the `cmake_targets` directory. Currently, the tool is developed to build the eNB for different hardware platforms, 3GPP releases, standalone or with S1 interface, unitary simulations, and system simulation.
+
+The build system for OAI uses cmake which auto-generates makefiles.
+
+## eNB Build Examples
+
+```shell
+git clone https://gitlab.eurecom.fr/oai/openairinterface5g.git
+cd YOUR_openairinterface5g_DIRECTORY
+source oaienv #Very important. It sets the correct environment variables.
+cd cmake_targets
+./build_oai -I --install-optional-packages (need to run only once)
+./build_oai -h (for more options)
+```
+
+### Install, Build eNB
+   * package installation + EXMIMO Driver Installation: `./build_oai -I --install-optional-packages`
+   * package installation + USRP Driver installation : `./build_oai -I --install-optional-packages -w USRP`
+   * package installation + BladeRF Driver Installation: `./build_oai -I --install-optional-packages -w BLADERF`
+   * eNB + EXMIMO + test: `./build_oai --eNB -w EXMIMO -c -s`
+   * eNB + USRP: `./build_oai --eNB -c -w USRP`
+   * eNB+ ETHERNET : `build_oai.bash --eNB -c -w ETHERNET`
+
+### Build LTE Simulations (L3/L2/L1)
+   * unitary L1 simulations: `./build_oai --phy_simulators`
+   * oaisim: `./build_oai --oaisim (build oaisim with S1 support)`
+   * oaisim_nos1: `./build_oai --oaisim --noS1` (build oaisim without S1 support)
+
+These will create directories under `cmake_targets` corresponding to the different targets. These are the main directories:
+   * lte_noS1_build_oai (see notes below for further building instructions) : L1/L2 + Linux IP interface (i.e. no S1 interface). This is a target which will work with and OAI eNB and OAI UE only.
+   * oaisim_build_oai : oaisim with S1
+   * lte_build_oai: eNB/UE build with S1/NAS
+   * lte-simulators: unitary PHY simulators
+   * oaisim_noS1_build_oai: oaisim without S1
+Notes:
+   * Add `-x` to enable xforms (soft scope)
+   * Add `-V` to enable VCD file generation
+   * Add `-K /tmp/itti_enb.log` for itti logs
+   * For lte_noS1_build_oai do the following:
+```shell
+cd lte_noS1_build_oai
+mkdir build
+cd build
+cmake ..
+make lte-softmodem -j4
+```
+
+## Building the EPC modules
+
+```shell
+git clone https://gitlab.eurecom.fr/oai/openair-cn.git
+cd YOUR_openair-cn_DIRECTORY
+cd SCRIPTS
+./build_epc -i #Need to run only once to install missing packages
+./build_hss -i #Need to run only once to install missing packages
+```
+
+The detailed instructions for EPC are located in: `YOUR_openair-cn_DIRECTORY/DOCS/EPC_User_Guide.pdf`
+
+## Building Older Releases
+
+The older releases of OAI (0.1, 0.2) use an older build system located in targets/ durectory. This build system is deprecated and should not be used unless you want to compile older releases. The instructions to compile older releases (0.1, 0.2) are located [here](OlderReleases).