Enabling & Support

Flexible Channel Decoder

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ESA / Enabling & Support / Space Engineering & Technology
562 - Abstract:
The European Space Agency (ESA) offers a flexible channel decoder to partners operating in telecommunication and mobile systems. The main innovation of such decoder is its real-time configurability and flexibility in decoding both Turbo and Low Density Parity Check codes, commonly used in communication standards due to their remarkable error correction performances. The exceptional advantage of the proposed device provides both low complexity and low power consumption with respect to existing solutions.

Description of the offer:

The proposed innovation is an advantageous decoder that allows highly improved wireless signals transmission. Nowadays, for most wireless applications the air is the main mean of transmission. Unfortunately this distribution channel may result in messages being highly disturbed by many errors and redundancies. At the same time the current demand for improved transmission is increasing strongly, as customers ask for high definition (HD) transmissions for TV or mobile applications and for improved streaming conditions in which the correction of transmitted data does not slow down the whole transmission system. Therefore the two main customers’ requests are better quality and higher reliability.

The problem with the decoding system, as it is conceived today, is that it relies on the fact that different applications require different decoding codes. For example, UMTS (Universal Mobile Telecommunications System) uses Turbocodes as its decoding system for the correction of data during the transmission, while most of the wireless LAN (Local Area Network) applications instead use Low Density Parity Check (LDPC) codes to perform such correction. The use of two different decoding systems is implied by compliance with different standards and methods. Such codes are widely used in modern communication standards due to their remarkable error correction performances but they are characterised by different algorithms, frame lengths, throughput and latency requirement.

Therefore, as current customers’ requests are trending towards implementing both systems in the same application (eg: smartphones, or other mobile communication systems which also require wireless streaming capacity) there is an increasing need for multi-standard decoding tools that, at the same time, respect requirements in terms of volume, efficiency and low power consumptions. Customers of telecommunication systems are requesting improved data services such as Short Message Service (SMS), Multimedia-Messaging Service (MMS) and Wireless Application Protocol (WAP) internet connections. In addition modern phones are designed to be capable of connecting to high speed cellular networks for mobile Internet, meaning it is therefore necessary to receive broadcast video and multimedia content with higher quality and reliability. Such a wide range of applications requires increasing data rates and high reliability in order to guarantee adequate service quality.

The proposed innovative decoding channel is the tool that allows users to optimise - for example - the use of wireless LAN and UMTS systems at the same time, as it provides a correction that supports both Turbocodes and LDPC correction systems in real time. The capability of supporting different communication standards represents a driving factor in keeping complexity, latency and power consumption under control. The proposed architecture is more flexible than existing ones and, with the use of only one decoder manages to support all systems, respecting all requirements in terms of space, weight and low power consumption.

Innovations and advantages of the offer:

The proposed technology provides a flexible Turbo/LDPC decoder, because the foreseen architecture allows the implementation of different parallelisation schemes with minimal hardware overhead. The innovation supports real-time multi-standard decoding systems and is highly flexible. Parallelisation is important to achieve high throughput and different parallelisation schemes have to be used when dealing with different communication standards. More particularly the switching network of this innovative decoder allows selective implementation of the following parallelisation schemes:

  • Simultaneous decoding of several Turbo encoded (eg UMTS);
  • Parallel decoding of a single Turbo-encoded;
  • Parallel decoding of a single LDPC (eg Wireless LAN) encoded frame.

Other innovations of the proposed innovative technology are the inclusion of:

  • A by-passable channel cumulative computation unit for computing channel cumulative messages by adding up input reliabilities;
  • A state-metric recursive unit for successively performing recursive computation of forward and backward metrics, taking the channel cumulative messages as inputs;
  • A state-metric memory for storing already computed forward metrics while the state-metric recursive unit is computing backward metrics or vice-versa;
  • An extrinsic reliability processor for computing extrinsic reliabilities for Turbo-decoding and soft outputs and check-to-variable metrics for LDPC decoding, taking forward metrics, backward metrics and channel cumulative messages as its inputs.

Domain of Application:

While the original decoder has been developed within the frame of space programmes, such a decoder has wider potential applications within mobile and communication systems with strict requirements in terms of weight, reliability, quality of the signal and optimum power consumption.

  • Data Communications.
  • Data communication omponents
  • Communications processors/network

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