Abstract: Considering that greedy routing may fail due to routing voids on random network topologies, greedy routing's deliverability is defined and studied in a typical hemi-sphere 3D sensor network deployment scenario. Based on nodes' distribution characteristics, the relationship between the sensor transmission radius and the probability of guaranteed delivery for greedy routing is analyzed. A very tight analytical upper bound on the sensor transmission radius to ensure the designed deliverability probability is derived, and the corresponding numerical solution of this upper bound is proposed. The correctness and tightness of the derived upper bound are verified by extensive simulations, and hence the results can be used to design the minimal transmission for actual sensor network deployment.