LTE and DVB-T signals

GNU Radio
1

Hi,
I have to generate DVB-T and LTE signals using gnuradio companion.
I’m in trouble because I don’t know how to set some parameters in the
OFDM
modulator block.

LTE signal:
transmission bandwith: 5MHz
FFT size: 512
Cyclic prefix length: 128
occupied subcarriers:300

My questions concerning LTE signal are:

  1. The number of occupied tones is the number of occupied subcarriers?
    2)Which value should I set for the payload length?

DVB-T signal:
transmission bandwith: 5MHz
FFT size: 8192 (8k)
occupied carriers:6817

My question concerning DVB-T signal is:
1)Which value should I set for the Payload length and the Cyclic prefix
length?

In both cases of LTE and DVBT signals is it correct to set INPUT TYPE as
“complex”?

If someone could help me, I would be very thankful.

2

Isabella,

If you are looking for a LTE modulator/demodulator, I have a project
called openLTE (openLTE download | SourceForge.net) that accomplishes
much of this. It does not currently support all of the LTE
specifications, but might be enough to get you going.

Regards,
Ben

3

Isabella,
I do not believe the OFDM mod block will provide you with what you need,
both DVB-T and LTE follow a highly defined structure that defines pilot
symbols and resource scrambling/user mapping that I doubt the OFDM block
can emulate without significant modification. If this only has to be
“DVB-T/LTE Like” then you could certainly make the statement that
occupied tones is relative to occupied subcarriers etc… however it
will not work with real hardware. What you could do is develop a
non-realtime cell-wide LTE/DVB-T demodulator but even then that isn’t a
completely simple task, just simpler than a transmitter.
Regards,John
Date: Mon, 2 Jul 2012 15:53:28 +0200
From: [email protected]
To: [email protected]
Subject: [Discuss-gnuradio] LTE and DVB-T signals

Hi,
I have to generate DVB-T and LTE signals using gnuradio companion.
I’m in trouble because I don’t know how to set some parameters in the
OFDM modulator block.

LTE signal:
transmission bandwith: 5MHz

FFT size: 512
Cyclic prefix length: 128
occupied subcarriers:300

My questions concerning LTE signal are:

  1. The number of occupied tones is the number of occupied subcarriers?
    2)Which value should I set for the payload length?

DVB-T signal:
transmission bandwith: 5MHz

FFT size: 8192 (8k)

occupied carriers:6817

My question concerning DVB-T signal is:
1)Which value should I set for the Payload length and the Cyclic prefix
length?

In both cases of LTE and DVBT signals is it correct to set INPUT TYPE as
“complex”?

If someone could help me, I would be very thankful.