Joint coding and decoding device and method for source channel

Abstract

In the invention, the codec is divided into two parts-encoder and decoder. The encoder comprises: a vector buffer of the inputted message source, an encode index generator; a channel signal outputting unit; a channel signal power and parameter memory; a re-built message source memory; and an encoding channel signal memory. The decoder comprises: a vector buffer of the inputted channel, a decode index generator, a re-built message source outputting unit; a decode channel signal memory and a re-built message source memory. The codec provided can the channel-optimized k-dimension channel signals from L-dimension message source after direct coding so as to implement the bandwidth compression and expansion of message source.

Description

technical field [0001] The invention belongs to the communication field, and in particular relates to an information source channel codec and a codec method. Background technique [0002] At present, most of the communication systems are established under the framework of the separation structure communication system based on Shannon's separation theory. As shown in Figure 1, it is a general model of a communication system with a separated structure: from the source to the sink, it is divided into five parts: source coding, channel coding, channel, channel decoding, and source decoding. [0003] The simplification and convenience brought by the separation design of the communication system objectively promote the development and application of the separation structure communication system, but at the same time it also brings some unavoidable inherent disadvantages: First, from the perspective of feasibility, the separation communication system requires The overall optimalit...

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Problems solved by technology

[0003] The simplification and convenience brought by the separation design of the communication system objectively promote the development and application of the separation structure communication system, but at the same time it also brings some unavoidable inherent disadvantages: First, from the perspective of feasibility, the separation communication system requires The overall optimality is achieved under the condition that the codec has infinite complexity and delay, which is unacceptable for real-time communication; second, the theory is no longer valid for non-ergodic and multi-user systems, that is, in these cases In this case, there is no longer a separate optimal system; third, after the channel quality drops to a certain threshold, the system immediately collapses (break down), that is, there is a threshold effect. At this time, the channel coding can no longer correct errors, so the separation system Lack of robustness to variable channels; Fourth, the separation system cannot improve the communication quality when the channel quality is improved relative to the design channel conditions, so the utilization rate of channel resources is low

Although the suboptimal Shannon direct source channel mapper for a specific source and channel characteristics can be obtained by using the power-limited channel optimization vector quantization iterative algorithm, the transmit power is not controllable at this time, specifically, although the optimization design process considers The power limit of the channel, but the encoder transmit power obtained by iterative optimization cannot guarantee to strictly meet the transmit power requirements, so it lacks practicability

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