Wireless and PLC standards have to cope with noisy channels. The advanced FEC codes like LDPC and turbo codes are the most competitive ones. Multi-standards devices (such as mobile phones with cellular and WiFi) are becoming more and more attractive but raise the issue of duplicating hardware. Trellis decoding is a good solution to share material and to achieve good throughputs on FEC multi-standard decoders. Such a technique added with natural parallelism underlines access memory conflicts on the LDPC decoding process, which decreases the decoding performance. This paper presents an optimized trellis design to avoid these access conflicts with no loss in decoding performance.