Voice Long Distance Transmission Using Audio Codec for Low-Performance Microcontrollers and LoRa Communication for Use in IoT

The Internet of Things (IoT) is a rapidly advancing field in the realm of technology. As IoT devices typically require low-power and low-performance systems, using popular audio codecs, such as FLAC (Free Lossless Audio Codec) or MP3 can be problematic due to their high-performance demands, including complex arithmetic operations as well as the calculations on floating point variables. In some cases, it is necessary to communicate over long distances in IoT systems. However, IoT devices are often far apart and have limited power supplies. To address these issues, the LoRa communication technique is commonly used for such devices, as it enables long-distance communication using very low-speed links, even less than 10 kbps. The proposed lossless and lossy voice codecs can help solve both problems. Lossless codecs use simple bit operations to reduce the number of bits required to store a single audio sample. This results in a smaller audio file size. The arithmetic operations required for this compression process are executed quickly, and do not require a high-performance microcontroller. Lossy codecs use principles from decision systems such as rough-set theory to create audio that is almost identical to the original, with very little difference that can’t be heard. Experiments show that either lossless, as well as lossy codec, reduces the size of the audio file making it possible to send via LoRa link, and are very fast (don’t need high-performance microcontrollers), so can be used in IoT systems.