Configuring OpenLTE eNodeB

Before we can actually start the eNodeB, we need to configure it.

Start the LTE eNodeB app in one temrinal:

LTE_fdd_enodeb

And connect to the control interface in another terminal:

telnet 127.0.0.1 30000

Note that in this state we do not started to transmit anything yet.

With the "help" command you can list the current configuration variables and their current values.

The most important parameters are the following:

band
bandwidth
dl_center_freq
mcc
mnc
tx_gain
rx_gain

Although the SDRs are usually not capable of transmitting more than a 100mW, you need to make sure that your network is not interefering with any commercial networks. If the authority catches you doing that, you can get prosecuted! For test setups it is better to use higher frequency bands (band 3 (DCS1800), band 7 (2600), or band 1 (2100)), because there are more unutilized spectrum available in those bands, and also the signal attenuates more which lowers the chance to interfere. You will need a spectrum analyzer, or you can yous your SDR device to analyze the surrounding spectrum and choose the "dl_center_freq", "band" and "bandwidth" parameters accordingly.

More about LTE bands: http://niviuk.free.fr/lte_band.php

Example:

With spectrum analysis you found out that unutilized bandwidth is available from 1825 to 1830Mhz.

First use an LTE EARFCN calculator to figure out the center frequency (dl_earfcn) of your network:

Go to: http://niviuk.free.fr/lte_band.php

Set the frequency to the middle (1822.5 in this case), and hit the "EARFCN" button. You will be given a list like this:

In the control terminal you need to issue the following commands:

write band 3
write bandwidth 5
write dl_earfcn 1375
write mcc 001
write mnc 01
write tx_gain 86
write rx_gain 30

Note that OpenLTE is usually tested with a 5MHz setup. Altough it is capable of any bandwidth the specification allows (1.4, 3, 5, 10, 15 and 20MHz), it is recommended to use 5MHz for initial setup. Also the tx_gain and rx_gain values in the above example are optimal for lab testing from a few meteres distance with 5-8dBi omni antennas. This is how your TX and RX antenna should be aligned:

You can also change the base address of the TUN interface and the DNS server address:

write ip_addr_start 0A000001
write dns_addr 08080808

Note that OpenLTE accepts IP addresses in hexadecimal format. In the above exmpale "0A000001" means IP address "10.0.0.1", and "08080808" means DNS server address "8.8.8.8". You need to make sure that the value of "ip_addr_start" is not conflicting with your current network setup! You can use this calculator to convert between decimal and hexadecimal IP addresses:

http://ncalculators.com/digital-computation/ip-address-hex-decimal-binary.htm

If you want to save everything to a configuration file, use the following commands:

write use_cnfg_file 1
write use_user_file 1

The text based configuration of your eNodeB and user database can be found in the /tmp folder:

LTE_fdd_enodeb.cnfg_db
LTE_fdd_enodeb.user_db

[Erik Silva]

Hi,

I am using OpenLTE EnodeB on a B210 attached to a Core i7 ASUS laptop USB3 UBUNTU 14.07.
My UE is a Nexus 5.

Unfortunately the Nexus sometimes displays the MCC and MNC and that´s all.
Rarely the EnodeB shows the RNTI when the Nexus try to connect, We had written the
Ki, Op and other keys using add_user. But the UE cannot connect to the EnodeB.

Is there anybody with OpenLTE running okay with a Nexus 5 UE connected?

Please send me the configuration. I tried many different configs.

Thanks

Erik

[hitesh kumar]

Hey ,
I want to make this project at my home and while i was checking price of this UHD driver installed (for Ettus SDRs)
GNURADIO it is going out my busget. I have my own laptop . but other hardware is going out of my budget . SO what is cheapest option for me and correct way to make this test LTE setup ready for my personal project. I really want to make it at home , and want step by step way to do it. I am not expert but still want to do this. Please help me Regards/Hitesh

[Erik Silva]

Our current config:

bandwidth 5
band 4
dl_earfcn 2075
n_ant 1
n_id_cell 0
mcc 901
mnc 70
cell_id 1
tracking_area_code 1
q_rx_lev_min -140
p0_nominal_pusch -70
p0_nominal_pucch -96
sib3_present 0
q_hyst 0
sib4_present 0
sib5_present 0
sib6_present 0
sib7_present 0
sib8_present 0
search_win_size 0
debug_type error warning info debug
debug_level radio phy mac rlc pdcp rrc mme gw user rb timer iface msgq
enable_pcap 0
ip_addr_start 0A000001
dns_addr 08080808
use_user_file 1
tx_gain 60
rx_gain 35