SE2: LTE Cell Scan

1) Experiment Overview

Experiment Definition: LTE Cell Scan experiment consists of 2 modes of operation. The modes are DEVELOPMENT and TESTBED. User logins to E-VM or C-VM based on the mode of operation and starts the experiment. In the end, results are stored in the VM and the user can obtain the logs and results.

Experiment Goals: The goal of this experiment is to search for LTE cells and captures key parameters of interest such as the frequency, EARFCN, Physical Cell ID, PRB, number of ports, and PSS power of detected cells. 

Mode Details:

TESTBED: It is an experiment that obtains cell information from real RF transmissions of LTE synchronization signals. 2 nodes are needed for this experiment. The node that is going to run cell search is receive only node.

DEVELOPMENT: It is an emulation experiment that passes the transmitted packets to the channel emulator. The receiver side acquires path loss applied signal from the emulator.

Requirements:

For TESTBED mode,

• 2 USRP

• 2 E-VM container

For DEVELOPMENT mode,

• 1 C-VM container

• 2 E-VM container

2) Performing the Experiment

There are 2 types of operation for cell search. Currently, development operation is supported.

2.A) Testbed Operation

Testbed operation requires 2 E-VM(Fixed-Fixed or Fixed-Portable Node). The user starts the eNodeB on the fixed node and cell scan on the portable or fixed node.  After the experiment, the user can obtain results and logs under the  /root/Results directory.

Machine #1 (Cell Search)

We assume the cell search is a portable node. Login to the E-VM corresponding to the portable node. Navigate to the folder containing all the Radio scripts.

$ cd /root/Profiles/ProfileScripts/Radio

Copy the cell search rx script as startRadio.sh

$ cp Samples/startSRSCellScan-RX.sh startRadio.sh 

Use an editor to uncomment the line /Radio/startRadio.sh in /root/startexperiment.sh and run the following command:

$ ./startexperiment.sh

At this point, the cell search starts. If you are done with your experiment, you need to run 

$ ./stopexperiment.sh

The results can be seen at /root/Results/. An example output is shown below.

Machine #2 (eNodeB)

We assume the transmitter is a fixed node. Login to the E-VM corresponding to the fixed node. Navigate to the folder containing all the Radio scripts.

$ cd /root/Profiles/ProfileScripts/Radio

Copy the cell search tx script as startRadio.sh

$ cp Samples/startSRSCellScan-TX.sh startRadio.sh 

Use an editor to uncomment the line /Radio/startRadio.sh in /root/startexperiment.sh and run the following command:

$ ./startexperiment.sh

At this point, the experiment starts. If you are done with your experiment, you need to run 

$ ./stopexperiment.sh

An example output is shown below.

2.B) Development Operation

Development operation requires 2 E-VM. The experiment contains 3 nodes. These are,

• Transmitter Node

• Channel Emulator Node

• Receiver Node

The transmitter node transmits packets to the receiver through the channel emulator. Channel emulator receives path loss information from channel control and channel control consistently updates the path loss information based on the scenarios. After the experiment, the user can obtain results and logs under the  /root/Results directory.

Machine #1 (RX)

We assume the transmitter is a fixed node. Login to the E-VM corresponding to the fixed node. Navigate to the folder containing all the Radio scripts.

$ cd /root/Profiles/ProfileScripts/Radio

Copy the cell search rx script as startRadio.sh

$ cp Samples/startSRSCellScan-RX.sh startRadio.sh 

Use an editor to uncomment the line /Radio/startRadio.sh in /root/startexperiment.sh and run the following command:

$ ./startexperiment.sh

At this point, the transmitter starts. If you are done with your experiment, you need to run 

$ ./stopexperiment.sh

Machine #2 (TX)

We assume the transmitter is a fixed node. Login to the E-VM corresponding to the fixed node. Navigate to the folder containing all the Radio scripts.

$ cd /root/Profiles/ProfileScripts/Radio

Copy the cell search tx script as startRadio.sh

$ cp Samples/startSRSCellScan-TX.sh startRadio.sh 

Use an editor to uncomment the line /Radio/startRadio.sh in /root/startexperiment.sh and run the following command:

$ ./startexperiment.sh

At this point, receiver(cell search) starts. If you are done with your experiment, you need to run 

$ ./stopexperiment.sh

An example output is shown below.

3) Modifying the Experiment Configuration Parameters:

TX Script Parameters:

TX_GAIN=70

EARFCN=2900

BAND=13

RX Script Parameters:

RX_GAIN=40

BAND=13

EARFCN_START=5230

EARFCN_END=5231

To modify configuration parameters, you should navigate to ./Radio/Samples/ directory and edit the file with your favourite editor.

UE:

For advanced users, the IP address per UE can be statically assigned. Please refer to section 4.1.1) SrsRan Experiments for further instruction

4) Results

Results can be viewed from /root/Results directory.