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Middleware for SH-Mobile descrambles DVB-H

Posted: 01 Nov 2007 ?? ?Print Version ?Bookmark and Share

Keywords:DVB-H? DTV broadcasts? middleware?

Renesas Technology Corp. has announced the DVB-H CA Middleware Package, software designed for the SH-Mobile application processor that implements descrambling of DTV broadcasts for mobile phones in Europe. The new DVB-H CA Middleware Package will be available from February 2008 in Japan.

The DVB-H CA Middleware Package was developed in collaboration with Systems Development Laboratory, Hitachi Ltd.

In recent years the trend in mobile phone systems is toward incorporation of support for DTV broadcasts as a standard multimedia function. The TV broadcast formats used by mobile phones include ISDB-T, which is the basis for the One-Seg service offered in Japan; DVB-H, which is used outside of Japan, particularly in Europe; and DMB-T, which is used in South Korea. To enable handset manufacturers to implement DTV reception on mobile phones, Renesas supplies the SH-Mobile application processor and solutions, especially middleware, for realizing video and audio functionality using the SH-Mobile. These are widely used in mobile phone models with support for terrestrial DTV.

On the other hand, to enable users to view DTV broadcasts in the DVB-H format used in Europe, mobile phones must have a descrambler function, in addition to the video and audio functions, because fee-based broadcasts are encrypted. This functionality is defined in the DVB-H standard as Service Purchase and Protection (SPP), and a mobile phone must support it in order for the user to watch fee-based broadcasts. In response, Renesas has developed the DVB-H CA Middleware Package, which provides support for DVB-H SPP, as an addition to the previously released DTV middleware components for mobile phones, which mainly focus on video and audio functions. The new offering expands the range of middleware components available for mobile phones with TV functionality, providing an effective solution for mobile phone TV application developers.

Product functions
The features of the middleware package are summarized below:

Easily customizable modular structure -The DVB-H CA Middleware Package has a modular structure and provides support for four independent functions: (1) content stream decoding, (2) key stream decoding, (3) authentication, and (4) decryption, the last two of which are utilized in (1) and (2). The modular structure simplifies customization to match the desired specifications. The developer can mix and match middleware modules as required. For example, a separately developed module could be used to implement the key stream decoding function while retaining the functionality provided by the other modules in the package unchanged. This simplifies application development and can shorten the amount of time needed for development by approximately 30 percent, according to tests carried out by Renesas.

High-performance encryption middleware - To support DVB-H CA it is necessary to perform decrypting and authentication on data encrypted in formats such as Advanced Encryption Standard (AES) or HMAC-SHA-1, and the processing this entails can place a substantial load on the CPU. The DVB-H CA Middleware Package is optimized along with the SH-Mobile architecture for the authentication functions and decryption, achieving a processing load, with a 512Kbps data stream of the sort used for mobile phone TV broadcasts, of about 5MHz for each of the both functions.

In addition, DVB-H CA requires that the AES key be updated frequently. This imposes a heavy load on the CPU, but the new middleware reduces this load by making key generation processing more efficient, enabling to support streams that update the key dynamically. These improvements reduce the CPU load imposed by DVB-H CA functions by approximately 40%, compared with earlier Renesas' middleware products providing encryption functionality. This contributes to a reduction in the current consumption of the entire system.

The DVB-H CA Middleware Package conforms to A100 SPP under the DVB-H standard covering scrambling and unscrambling of fee-based TV broadcasts in Europe. It provides decoding functionality that supports the following content and key encryption specifications:

- Encrypted content streams conforming to Secure Real Time Protocol (SRTP) and Internet Streaming Media Alliance: Encryption and Authentication Specification (ISMACryp) Ver. 1.1

- Key streams conforming to the A100 Annex B specification of DVB-H

To implement this functionality, the DVB-H CA Middleware Package comprises a total of four middleware modules: two decode middleware modules that support two types of streams, and two encryption middleware modules. The four middleware modules are: (a) key stream decode middleware module, (b) content stream decode middleware module, (c) hash function HMAC-SHA-1 encryption middleware module, and (d) AES encryption middleware module. Their functions are as follows.

- Key stream decode middleware module: Analyzes the key stream and decodes and extracts the keys to be used to decode the content.

- Content stream decode middleware module: Analyzes the received content stream, obtains the decoding keys, and decodes the content.

- Hash function HMAC-SHA-1 middleware module: Determines whether the key and content streams being received are proper one.

- AES encryption middleware module: Decrypt encrypted key and content streams in 128bit block units.

Note that middleware modules (c) and (d) are for general use and can be utilized for applications other than mobile phone TV reception.

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