Added documentation

doc/RUN_NR_multiple_BWPs.md

+# Procedure to add dedicated Bandwidth part (BWP)
+
+## Contributed by 5G Testbed IISc 
+
+### Developers: Abhijith A, Shruthi S
+
+# Terminology #
+
+## Bandwidth part (BWP) ##
+Bandwidth Part (BWP) is a set of contiguous Resource Blocks in the resource grid. 
+
+Parameters of a Bandwidth Part are communicated to UE using RRC parameters: BWP-Downlink and BWP-Uplink. 
+
+A UE can be configured with a set of 4 BWPs in uplink (UL) and downlink (DL) direction. But only 1 BWP can be active in UL and DL direction at a given time.
+
+# Procedure to run multiple dedicated BWPs #
+
+A maximum of 4 dedicated BWPs can be configured for a UE.
+
+To configure multiple BWPs, add the following parameters to the gNB configuration file under "servingCellConfigDedicated": 
+
+## Setup of the Configuration files ##
+```
+    firstActiveDownlinkBWP-Id = 1; #BWP-Id 
+    defaultDownlinkBWP-Id = 1; #BWP-Id 
+    firstActiveUplinkBWP-Id = 1; #BWP-Id 
+```
+
+Each dedicated BWP must have:
+```
+    # BWP 1 Configuration 
+    bwp-Id_1 = 1; 
+    bwp1_locationAndBandwidth = 28908; // RBstart=33,L=106 
+    # subcarrierSpacing 
+    # 0=kHz15, 1=kHz30, 2=kHz60, 3=kHz120  
+    bwp1_subcarrierSpacing = 1; 
+```   
+
+ Find these parameters in this configuration file: "targets/PROJECTS/GENERIC-LTE-EPC/CONF/gnb.band78.tm1.106PRB.usrpn300.SCD.conf"
+
+###  NOTE:  
+    * For changing bandwidth, 'dl_carrierBandwidth' and 'ul_carrierBandwidth' must be modified according 
+      to the bandwidth of the BWP
+    * Currently only 'firstActiveDownlinkBWP-Id' is used to configure both DL and UL BWPs
+     
+# Testing gNB and UE in RF simulator
+
+## gNB command:
+```
+    sudo RFSIMULATOR=server ./nr-softmodem -O ../../../targets/PROJECTS/GENERIC-LTE-EPC/CONF/gnb.band78.tm1.106PRB.usrpn300.SCD.conf --rfsim --phy-test -d
+```
+
+## UE command:
+```
+    sudo RFSIMULATOR=127.0.0.1 ./nr-uesoftmodem --rfsim --phy-test -d
+```
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