Joint Source-Channel Coding System for 6G Communication: Design, Prototype and Future Directions

The emergence of the AI era signifies a shift in the future landscape of global communication networks, wherein robots are expected to play a more prominent role compared to humans. The establishment of a novel paradigm for the development of next-generation 6G communication is of utmost importance for semantics task-oriented empowered communications. The goal of semantic communication lies in the integration of collaborative efforts between the intelligence of the transmission source and the joint design of source coding and channel coding. This characteristic represents a significant benefit of joint source-channel coding (JSCC), as it enables the generation of source alphabets with diverse lengths and achieves a code rate of unity. Therefore, we leverage not only quasi-cyclic (QC) characteristics to facilitate the utilization of flexible structural hardware design but also Unequal Error Protection (UEP) to ensure the recovery of semantic importance. In this study, the feasibility of using a semantic encoder/decoder that is aware of UEP can be explored based on the existing JSCC system. This approach is aimed at protecting the significance of semantic task-oriented information. Additionally, the deployment of a JSCC system can be facilitated by employing QC-Low-Density Parity-Check (LDPC) codes on a reconfigurable device. The QC-LDPC layered decoding technique, which has been specifically optimized for hardware parallelism and tailored for channel decoding applications, can be suitably adapted to accommodate the JSCC system. The performance of the proposed system is evaluated by conducting BER measurements using both floating-point and 6-bit quantization. This is done to assess the extent of performance deterioration in a fair manner. The fixed-point system is synthesized and subsequently used as a semantic feature transmission and reception system across a noisy channel, with the aim of presenting a prototype for semantic communications. This study concludes with some insights and potential research avenues for the JSCC prototype in the context of future communication.