Multi-standard Digital Radio White Paper, June 2008

Contents

1 Introduction

2 Market situation

3 DMB-audio - assumptions in this white paper

4 Solutions for Eurika-147

5 Feasibility of multi-standard receivers

5.1 Chorus 2/Kino 2 Outline

5.1.1 Processing Elements
5.1.2 User Interface
5.1.3 Peripherals
5.1.4 DMB Support
5.1.5 Audio Decoders

6 Multi-standard receiver Venice 5.1

7 Conclusion

1 Introduction

This white paper is intended to outline the requirements for multi-standard digital radio solutions for the European market and the feasibility of such a solution

2 Market situation

There are currently several variants of the Eureka-147 digital radio standard being used or being proposed for broadcasting digital audio and in some cases multimedia content. These include: -

• Standard DAB – being used commercially in UK, Denmark, Switzerland and Norway. Also being broadcast in Germany but not seen as a commercial success
• DAB+ - Chosen by Australia for their roll out in early 2009 and will also be adopted in Switzerland. Potential for Germany to also adopt
• DMB-Audio – Chosen by France for their roll out in 2009. Also under consideration by parts of the German broadcast industry

Currently the existence of these different standards makes it more difficult for manufacturers to commit to Europe-wide Digital Radio projects. This is particularly hard for the vehicle manufacturers who want a product that will work across Europe before they will commit to fitting Digital Radio as a standard fit, but this is also an issue for standard audio manufacturers who want to be able to make a single product for sale across Europe to give them the benefits of scale.

3 DMB-audio - assumptions in this white paper

Through various contacts with the industry Frontier is making the following assumptions in this white paper about what is contained in the DMB-Audio specification being put forward in France: -

• Band 3/L-Band RF receiver
• Audio HE-AAC
• Video MPEG4 AVC (H.264)
• Graphics MPEG-4 BIFS
• Multiplex MPEG-2 TS
• RS(204,188), Convolutional Byte interleaver

We believe that to enable the market for low cost receivers alongside the higher functionality products it will be desirable to make some of these features optional.

These assumptions are based on our best evaluation with the information available and will be refined as specifications become more solid.

4 Solutions for Eurika-147

Typically receivers for Eureka-147 products are made up of the following semiconductors: -

• RF tuner – supporting Band 3 and optionally L-Band
• Demodulation IC
• Memory
• Audio DAC

The memory and Audio DAC are common components across all three versions of the standard. The quantity of memory required does vary between the different versions of the standard, with standard DAB requiring the least and DAB+ and DMB-Audio requiring more.

The RF tuner is interchangeable between all of the different standards, so the only consideration that needs to be made is if support for L-Band is necessary or not. Most territories have licensed Band 3 for Eureka-147 transmissions so today normally receivers tend to be Band 3 only on cost grounds. However with the advent of more advanced tuner ICs then the cost of adding L-Band is coming down and over the next 2-3 years it is likely that all receivers will support both Band 3 and L-Band.

The demodulation IC normally contains the blocks required to demodulate the signal, error correction and the means to rebuild the transmitted content in the correct multiplex structure. Most of these ICs also contain the audio decoder functionality. Often the demodulation is implemented in hardware to minimize power consumption and the upper layers such as the error correction and multiplexing may be done by either hardware or software, or as a mixture of the two.

The demodulation itself is common across DAB/DAB+/DMB-Audio, but there are differences in the error correction schemes and the multiplexing of the different versions of the standard. So it is in the demodulation IC where the differences between DMB-Audio and DAB/DAB+ must be taken care of.

5 Feasibility of multi-standard receivers

This white paper uses the Frontier Silicon Chorus 2/Kino 2 processor as the basis for the analysis. Other DAB chipsets may or may not share similar characteristics with these devices.

5.1 Chorus 2/Kino 2 Outline

These processors are based on 0.13 um CMOS technology and have been developed, and are marketed, by Frontier Silicon. They are used on several market leading digital radio modules that have been in volume mass production for over two years. In excess of 3 million units have been deployed to date.

5.1.1 Processing Elements

The basis of these processors is a high speed, multi-threaded DSP called META (licensed from Imagination Technologies Ltd). They also contain dedicated hardware for implementing some of the processing intensive tasks in demodulation and error correction for Eureka-147 broadcasts. The higher levels of the Eureka-147 task such as framing and audio decoding are performed in software running on the META DSP.

5.1.2 User Interface

As it is a multi-threaded DSP, META can also perform other tasks, such as driving the radio’s user interface while at the same time decoding the incoming signal.

5.1.3 Peripherals

Chorus 2 and Kino 2 also contain a large number of peripheral blocks (USB, I²S etc.) that are useful in audio system design.

5.1.4 DMB Support

When Chorus 2 and Kino 2 were developed the requirements of DAB/DAB+ and DMB were all taken into account and specific hardware elements, such as a Reed Solomon block, were added to ensure that DMB is as well supported as DAB/DAB+. An implementation of T-DMB was also developed running on these processors and this is still being deployed today in T-DMB products in Korea.

5.1.5 Audio Decoders

For DAB applications a MUSICAM audio decoder is run on the META DSP. For DMB-Audio and DAB+ a HE-AAC decoder is also run on the META DSP

6 Multi-standard receiver Venice 5.1

Using the example of Chorus 2 and Kino 2 it can be shown that a single receiver can be reconfigured to receive DAB, DAB or DMB-Audio through software. The areas of difference between the standards are handled in Chrous 2/Kino 2 as software tasks which allows this flexibility

An example of a multi-standard receiver is the Venice 5.1 modules shown below. Venice 5.1 is based on Kino 2 so through software it can be adapted to decode DAB, DAB+ and DMB-Audio. In it’s first iteration it is ,multi-standard implementation of DAB and DAB+. Frontier is now working on a firmware upgrade that will then allow the Venice 5.1 module to also decode DMB-Audio.

7 Conclusion

While there is some discussion ongoing about which versions of the Eureka-147 will be adopted in different geographical regions it should not be forgotten that all of these versions have the same base. Having the same base does enable receiver manufacturers to offer solutions that can take care of regional differences in broadcast standard. Venice 5.1 is such a solution.