PRDC: an ASIC device for lossless data compression implementing the Rice algorithm

The new generation of Remote Sensing instruments usually generates a huge amount of data, which have to be transmitted down to a ground station for processing. In order to reduce the bit rate before the data is transmitted to the ground station, data compression is usually used. Developing ASICs for the data compression can save power and weight, and can increase the level of integration. Data compression can be done in basically two ways, compression with or without loss, i.e. losing/not losing any information. The purpose of this paper is to present the PRDC (Payload Rice Data Compressor), the ASIC data compressor developed within an European Space Agency (ESA) project, that implements the Rice algorithm for lossless data compression, which has been recommended by CCSDS. The Rice algorithm is an adaptive noiseless, i.e. no loss, algorithm that is particularly useful for encoding data of variable entropy. The device implements an extension to the Rice algorithm outside the CCSDS definition. It is however always possible to disable these extensions in order to comply with the standard Rice algorithm. The output of the PRDC is however fully compliant with a standard Rice decompressor. The PRDC is able to handle samples with a size of 4 up to 24 bits, except for the case when prediction is enabled and mapping is disabled then only sample sizes up to 23 bits are supported. From a technologic point of view, the PRDC ASIC is a radiation-hardened component. The manufacturing process is TEMIC MG1RT 0.6 mum SCMOS2/2RT with 3 metal layers. The complexity is in the order of 70 Kgates. In this paper, the ASIC implementation and functionalities will be presented. Moreover, a test bench developed in order to validate the ASIC will be illustrated