HowtoconnectCOTSUEtoOAIeNBviaRRHGW.md

 # How to Connect OAI eNB with COTS UE via the OAI RRH GW (USRP-B210)
 
+**The instructions in this tutorial are valid only for older version of openair-cn (tag v0.3.2)**
+
 In this tutorial, we will describe how to connect a commercial off-the-self UE (i.e. smartphone and LTE dongle) with the C-RAN version of the OAI eNB. As it is dictated by the C-RAN concept the radio front end hardware is detached from the eNB and is incorporated to a remote radio head (RRH) instead which is connected to the eNB. Within the framework of OAI this concept is realized as follows:
 * the OAI eNB functionality is extended so that OAI eNB is able to interface via Ethernet a RRH 
 * a new software entity is introduced, namely the OAI RRH GW which acts as an abstraction between radio front end equipment (e.g. USRPB210, BLADERF and LMSSDR) and the OAI eNB
@@ -74,6 +76,7 @@ labuser@labuser:$ cat /etc/hosts
 #### Step 3: Run automated scripts for openair-cn
 
 ```shell
+git checkout v0.3.2
 ./build_epc -i #(Need to run only once to install missing packages)
 ./build_hss -i #(Need to run only once to install missing packages)
 ```