Localization is a fundamental issue for many wirelessnetwork applications. Without additional ranging devises, therange-free localization scheme offers a cost-effective solution forlow-cost indoor sensor networks. As a typical range-freealgorithm, DV-hop (Distance Vector - hop) algorithm has theadvantage to localize normal nodes that have less than threeneighbor anchors. In order to implement the DV-hop basedalgorithms in network scenarios, we create a new DV-hoplocalization protocol. This new protocol is presented in this paperwith details, including the frame formats, the improvement ofmedium access method, as well as parameters used in decidingthe end of each DV-hop step. Finally, using the new localizationprotocol, we investigate into some DV-hop algorithms (DV-hop,Checkout DV-hop and Selective 3-Anchor DV-hop) in terms oflocalization accuracy and synchronization. Simulation resultsshow the good performance of our localization protocol.