We recently presented new methods for the compression, the decompression and the transport of media (audio, image and video).
For more information, see at the following addresses:

Image and Video Compression

Long Distance Communications

We also reported that these methods are usable with OFDM, OFDMA and SC-FDMA.
For more information, see at the following address:

Multimedia Codecs based on FFT and Usable with OFDM, OFDMA and SC-FDMA

This information is written for investors, developers and decision makers.
This article aims to show how these methods can be used with OFDM-IM (OFDM-Index Modulation).

In some cases (such as for frequency-selective fading channels in the presence of high mobility), it may be more interesting to use OFDM with the index modulation.
This approach is inspired by the concept of spatial modulation introduced for multiple-input multiple-output (MIMO) channels.
For more information on OFDM-IM or MIMO-OFDM, see at the following addresses:

OFDM-IM

MIMO-OFDM

The index modulation can improve the PAPR (Peak to Average Power Ratio), improve the spectral efficiency or decrease the BER (Bit Error Rate).
The index modulation can result in lower power consumption and transmitter complexity compared to the conventional orthogonal frequency division multiplexing systems, but the overall performance of the OFDM system with IM is significantly influenced by the accuracy of the index bit detection.

We recall that when transporting media, we can use the phases of the background to transport the foreground or pure data.
We can also implement the decimation in the background (the largest point out of N contains the codec data, the other points being set to zero).
With the virtual decimation, we can:
- Use the non-decimable points to contain the magnitudes and the possible phases of the codec.
- Use the phases and possibly the magnitudes of the decimable points to transport the data.
We must ensure that the magnitudes of the decimable points are not greater than those of the non-decimable points or those of the foreground points.

To implement the index modulation with our methods, we give ourselves the possibility to select the background points carrying the foreground points and/or the additional data.
We can:
- Use the phases of the non-decimable points to encode the indices.
- Use the decimated and decimable points to apply the modulations.
- Increase the modulation bits by giving ourselves the possibility to activate the phases only, the magnitudes only, or both at the same time.
The detection of the index bits is automatic because they are encoded in the phases of the non-decimable points, which are the largest local points.

The null points of the removed foreground can be included in the virtual decimation area. In this area, the magnitudes of the largest points out of N can be used to encode the indices. Indeed, when receiving a frame, we first decode all the phases and find the foreground points.
We can also reserve some background bands to encode the indices in the phases and/or the magnitudes.

Some background points do not directly carry data, there is an improvement in PAPR and an improvement in spectral efficiency via the index modulation.