docs: Standardize documentation headings (remove multiple # H1)

- Remove multiple single top-level (# H1) headings per file
 - Use (# H2 and ###### H6) sub-headings for consistency
 - Remove any trailing # in the headings
 - This ensures proper table of contents rendering in MkDocs.

 - Also removed RUN_NR_multiple_BWPs.md as it is moved to MAC usage

doc/NR_SA_Tutorial_OAI_nrUE.md

@@ -16,7 +16,7 @@
 
 [[_TOC_]]
 
-#  1. Scenario
+##  1. Scenario
 In this tutorial we describe how to configure and run a 5G end-to-end setup with OAI CN5G, OAI gNB and OAI nrUE.
 
 Minimum hardware requirements:
@@ -38,19 +38,19 @@ Minimum hardware requirements:
     - Please identify the network interface(s) on which the USRP is connected and update the gNB configuration file
 
 
-# 2. OAI CN5G
+## 2. OAI CN5G
 
-## 2.1 OAI CN5G pre-requisites
+### 2.1 OAI CN5G pre-requisites
 
 Please install and configure OAI CN5G as described here:
 [OAI CN5G](NR_SA_Tutorial_OAI_CN5G.md)
 
 
-# 3. OAI gNB and OAI nrUE
+## 3. OAI gNB and OAI nrUE
 
-## 3.1 OAI gNB and OAI nrUE pre-requisites
+### 3.1 OAI gNB and OAI nrUE pre-requisites
 
-### Build UHD from source
+#### Build UHD from source
 ```bash
 # https://files.ettus.com/manual/page_build_guide.html
 sudo apt install -y autoconf automake build-essential ccache cmake cpufrequtils doxygen ethtool g++ git inetutils-tools libboost-all-dev libncurses-dev libusb-1.0-0 libusb-1.0-0-dev libusb-dev python3-dev python3-mako python3-numpy python3-requests python3-scipy python3-setuptools python3-ruamel.yaml
@@ -69,7 +69,7 @@ sudo ldconfig
 sudo uhd_images_downloader
 ```
 
-## 3.2 Build OAI gNB and OAI nrUE
+### 3.2 Build OAI gNB and OAI nrUE
 
 ```bash
 # Get openairinterface5g source code
@@ -89,59 +89,59 @@ cd ~/openairinterface5g/cmake_targets
 ./build_oai -w USRP --ninja --nrUE --gNB --build-lib "nrscope" -C
 ```
 
-# 4. Run OAI CN5G and OAI gNB
+## 4. Run OAI CN5G and OAI gNB
 
-## 4.1 Run OAI CN5G
+### 4.1 Run OAI CN5G
 
 ```bash
 cd ~/oai-cn5g
 docker compose up -d
 ```
 
-## 4.2 Run OAI gNB
+### 4.2 Run OAI gNB
 
 **Note:** From tag `2024.w45`, OAI gNB runs by default in standalone (SA) mode.  
 In earlier versions the default mode was non-standalone (NSA).  
 If you are using an earlier version than `2024.w45`, you should add the `--sa` argument to the sample commands below to obtain a correct behavior.
 
-### USRP B210
+#### USRP B210
 ```bash
 cd ~/openairinterface5g/cmake_targets/ran_build/build
 sudo ./nr-softmodem -O ../../../targets/PROJECTS/GENERIC-NR-5GC/CONF/gnb.sa.band78.fr1.106PRB.usrpb210.conf --gNBs.[0].min_rxtxtime 6 -E --continuous-tx
 ```
-### USRP N300
+#### USRP N300
 ```bash
 cd ~/openairinterface5g/cmake_targets/ran_build/build
 sudo ./nr-softmodem -O ../../../targets/PROJECTS/GENERIC-NR-5GC/CONF/gnb.sa.band77.fr1.273PRB.2x2.usrpn300.conf --gNBs.[0].min_rxtxtime 6 --usrp-tx-thread-config 1
 ```
 
-### USRP X300
+#### USRP X300
 ```bash
 cd ~/openairinterface5g/cmake_targets/ran_build/build
 sudo ./nr-softmodem -O ../../../targets/PROJECTS/GENERIC-NR-5GC/CONF/gnb.sa.band77.fr1.273PRB.2x2.usrpn300.conf --gNBs.[0].min_rxtxtime 6 --usrp-tx-thread-config 1 -E --continuous-tx
 ```
 
-### RFsimulator
+#### RFsimulator
 ```bash
 cd ~/openairinterface5g/cmake_targets/ran_build/build
 sudo ./nr-softmodem -O ../../../targets/PROJECTS/GENERIC-NR-5GC/CONF/gnb.sa.band78.fr1.106PRB.usrpb210.conf --gNBs.[0].min_rxtxtime 6 --rfsim
 ```
 
-### RFsimulator in FR2
+#### RFsimulator in FR2
 ```bash
 cd ~/openairinterface5g/cmake_targets/ran_build/build
 sudo ./nr-softmodem -O ../../../targets/PROJECTS/GENERIC-NR-5GC/CONF/gnb.sa.band257.u3.32prb.usrpx410.conf --rfsim
 ```
 
-# 5. OAI UE
+## 5. OAI UE
 
-## 5.1 Run OAI nrUE
+### 5.1 Run OAI nrUE
 
 **Note:** From tag `2024.w45`, OAI nrUE runs by default in standalone (SA) mode.  
 In earlier versions the default mode was non-standalone (NSA).  
 If you are using an earlier version than `2024.w45`, you should add the `--sa` argument to the sample commands below to obtain a correct behavior.
 
-### USRP B210
+#### USRP B210
 Important notes:
 - This should be run in a second Ubuntu 22.04 host, other than gNB
 - It only applies when running OAI gNB with USRP B210
@@ -152,7 +152,7 @@ cd ~/openairinterface5g/cmake_targets/ran_build/build
 sudo ./nr-uesoftmodem -r 106 --numerology 1 --band 78 -C 3619200000 --ue-fo-compensation -E --uicc0.imsi 001010000000001
 ```
 
-### RFsimulator
+#### RFsimulator
 Important notes:
 - This should be run on the same host as the OAI gNB
 - It only applies when running OAI gNB with RFsimulator
@@ -163,7 +163,7 @@ cd ~/openairinterface5g/cmake_targets/ran_build/build
 sudo ./nr-uesoftmodem -r 106 --numerology 1 --band 78 -C 3619200000 --uicc0.imsi 001010000000001 --rfsim
 ```
 
-### RFsimulator in FR2
+#### RFsimulator in FR2
 Important notes:
 - This should be run on the same host as the OAI gNB
 - It only applies when running OAI gNB with RFsimulator in FR2
@@ -174,7 +174,7 @@ cd ~/openairinterface5g/cmake_targets/ran_build/build
 sudo ./nr-uesoftmodem -r 32 --numerology 3 --band 257 -C 27533280000 --uicc0.imsi 001010000000001 --ssb 72 --rfsim
 ```
 
-### Connection to an NG-Core
+#### Connection to an NG-Core
 
 A configuration file can be fed to the nrUE command line in order to connect to the local NGC.
 
@@ -213,15 +213,15 @@ More details available at [ci-scripts/yaml_files/5g_rfsimulator/README.md](../ci
 In earlier versions the default mode was non-standalone (NSA).  
 If you are using an earlier version than `2024.w45`, you should add the `--sa` argument to the sample commands above to obtain a correct behavior.
 
-## 5.2 End-to-end connectivity test
+### 5.2 End-to-end connectivity test
 - Ping test from the UE host to the CN5G
 ```bash
 ping 192.168.70.135 -I oaitun_ue1
 ```
 
-# 6. Advanced configurations (optional)
+## 6. Advanced configurations (optional)
 
-## 6.1 USRP N300 and X300 Ethernet Tuning
+### 6.1 USRP N300 and X300 Ethernet Tuning
 
 Please also refer to the official [USRP Host Performance Tuning Tips and Tricks](https://kb.ettus.com/USRP_Host_Performance_Tuning_Tips_and_Tricks) tuning guide.
 
@@ -243,20 +243,20 @@ sudo sysctl -w net.core.rmem_default=62500000
 sudo ethtool -G enp1s0f0 tx 4096 rx 4096
 ```
 
-## 6.2 Real-time performance workarounds
+### 6.2 Real-time performance workarounds
 - Enable Performance Mode `sudo cpupower idle-set -D 0`
 - If you get real-time problems on heavy UL traffic, reduce the maximum UL MCS using an additional command-line switch: `--MACRLCs.[0].ul_max_mcs 14`.
 - You can also reduce the number of LDPC decoder iterations, which will make the LDPC decoder take less time: `--L1s.[0].max_ldpc_iterations 4`.
 
-## 6.3 Uplink issues related with noise on the DC carriers
+### 6.3 Uplink issues related with noise on the DC carriers
 - There is noise on the DC carriers on N300 and especially the X300 in UL. To avoid their use or shift them away from the center to use more UL spectrum, use the `--tune-offset <Hz>` command line switch, where `<Hz>` is ideally half the bandwidth, or possibly less.
 
-## 6.4 Timing-related Problems
+### 6.4 Timing-related Problems
 - Sometimes, the nrUE would keep repeating RA procedure because of Msg3 failure at the gNB. If it happens, add the `-A` option at the nrUE and/or gNB side, e.g., `-A 45`. This modifies the timing advance (in samples). Adjust +/-5 if the issue persists.
 - This can be necessary since certain USRPs have larger signal delays than others; it is therefore specific to the used USRP model.
 - The x310 and B210 are found to work with the default configuration; N310 and x410 can benefit from setting this timing advance.
 - For example if the OAI UE uses the X410 and the gNB based on [Nvidia Aerial and Foxconn](./Aerial_FAPI_Split_Tutorial.md) a timing advance of 90 has been found to work well.  
 
 
-## 6.5 Lower latency on user plane
+### 6.5 Lower latency on user plane
 - To lower latency on the user plane, you can force the UE to be scheduled constantly in uplink: `--MACRLCs.[0].ulsch_max_frame_inactivity 0` .