Implementation of DPIM Modem on FPGA and Comparison of its Functionality with PPM Modem

Free space optic communications has received extensive interest over the past decade, and many potential applications for this technology have been suggested. Among various digital modulation formats for wireless optical links like OOK, PPM, DPIM and MDPIM, DPIM has got advantages in terms of transmission capacity, bandwidth requirement, power requirement and receiver design. DPIM displays a higher transmission capacity by eliminating all the unused time slots from within each symbol in PPM; and decreased bandwidth requirement and afford the possibility to introduce some redundancy into the code for security. Design of PPM receiver has more complexity compared to OOK and DPIM since both slot and symbol synchronizations are required at the receiver. In this study, DPIM Modem is implemented on FPGA and its Functionality is compared with PPM Modem.