This paper proposes a novel radio access mechanism for massive Internet of Things (IoT) services over TV White Spaces (TVWS). The proposal considers TVWS as the suitable frequency bands for facing the limited-spectrum problem in massive IoT services. The radio access mechanism is based on regulatory policies by interacting with a TVWS Geolocation Database through the Protocol to Access White-Space (PAWS) and using several Master Devices (MD)s. With this approach, IoT devices require neither geolocation receiver in the deployments, nor different frequency bands for initialization process within PAWS. Regarding the evaluation of the radio access mechanism, we explore different types of deployments and coverage areas. This paper also describes the optimization process to obtain the maximum service area, while maintaining an outage probability below a given objective. Moreover, we evaluate the performance of a loaded network with the maximum service area, with respect to a reference case with one MD. We evidence that the average packet loss probability is reduced by 26% when the load is equal to 80% in our proposal.