Abstract—Passive Optical Network (PON) technologies have been deployed widely for Fiber-To-The-Home (FTTH) services. PON configures the star topology network via passive optical splitters as downstream traffic is mature in FTTH. Generally, PONs provide an economical solution by reducing the cabling cost, footprint in the central office, and energy consumption. With these advantages, PON is a promising candidate for aggregating numerous end devices in various IoT services. However, in some IoT services, the quality of upstream traffic should be guaranteed. This paper proposes a new PON architecture for IoT services with guaranteed dedicated bandwidth for the upstream traffic. This simplified and economical PON is named Subcarrier Digital Modulation PON (SDM-PON). Career multiplexed within standardized bandwidth and digital modulation are applied in this architecture. The mechanism of SDM-PON is also described. SDM-PON was verified through the transmission simulator and use cases for local IoT services, e.g., services for industrial fields and social infrastructure.