REEDS-DECO-O4-N1 Lattice

TM ispLever CORECORE Reed-Solomon Decoder Users Guide October 2005 ipug07 04.0 Lattice Semiconductor Reed-Solomon Decoder Users Guide Introduction Lattices Reed-Solomon Decoder core provides an ideal solution that meets the needs of todays forward error cor- rection applications. The Reed-Solomon Decoder core provides a customizable solution allowing forward error cor- rection of data in many communication applications. This core allows designers to focus on the application rather than the Reed-Solomon Decoder, resulting in a faster time to market. Reed-Solomon codes are widely used in various applications for forward error correction and detection. Lattices Reed-Solomon Decoder core is a fully synchronous core developed in conjunction with Lattices Reed-Solomon Encoder core to provide a complimentary pair. For more information on these and other Lattice products, refer to the Lattice web site at www.latticesemi.com. This users guide explains the functionality of the Reed-Solomon Decoder core and how it can be implemented to provide decoding on any data transmission. It also explains how to achieve the maximum level of performance. The Reed-Solomon Decoder core comes with the documentation and les listed below: Data sheet Lattice gate level netlist RTL simulation model Core instantiation template Features Forward Error Correction (FEC) for communication and common applications Selectable Reed-Solomon standards: CCSDS (255,223) ATSC (207,187) DVB (204,188) OC192 (255,239) Shortened codes supported Fully synchronous design Error/erasures supported Supports symbol widths from 3 to 12 bits, corresponding to GF(8) and GF(4096) respectively User-dened and default eld and generator polynomials supported Generates failure ags and measurement information General Description Reed-Solomon codes are used to perform Forward Error Correction. FEC encoders introduce redundancy in data before it is transmitted. The redundant data (check symbols) are transmitted along with the original data through the channel. A Reed-Solomon decoder at the receiver is used to recover any corrupted data This type of error cor- rection is widely used in data communications applications such as hard disk and media storage (CD) systems, Digital Video Broadcast (DVB) and Optical Carriers (e.g. OC-192). The codes are represented by the format RS(n,k) where n is the total number of s-bit wide symbols, and k is the number of s-bit wide information (data) symbols in a codeword. The Reed-Solomon Decoder performs detection and correction of encoded data available at the receiver after demodulation. The RS encoded data is then pro- cessed to determine whether any errors have occurred during transmission. Once the number of errors is deter- mined, the decoder decides if they are within the range of correction. After determining this, the decoder corrects the errors in the received data. A typical application of space signal processing is shown in Figure 1. 2