## 2 Related Works
### Data Dissemination Algorithms in VANETs  
Data dissemination algorithms based on broadcast procedure can be classified in several ways, such as single-hop versus multi-hop, deterministic versus probabilistic [8], and vehicle-to-vehicle versus vehicle-to-infrastructure communications [9]. Regarding the present work, the proposed data dissemination is based on multi-hop communications since vehicles will exchange information in a multi-hop fashion to calculate the dissimilarity metrics from the source vehicle until every vehicle has received a given message. The multi-hop procedure is preferred when the target application requires a high dissemination throughout the network, for instance, when safety messages should be spread out. Probabilistic approaches are suitable for robust communications since they give to each vehicle in the network the opportunity to participate in the data dissemination. They are also preferred in case of high-density scenarios. Furthermore, in this work only communications among vehicles are considered, therefore, we do not consider vehicle-to-infrastructure communications. In [9], the authors also classify the data dissemination algorithms with respect to the target VANET scenario layouts, such as highway and urban scenarios. The data disseminations algorithms present different features depending on the target layout. For instance, the speed of vehicles plays an important role in case of highways scenarios, while it is expected a moderately low speed of vehicles in case of urban scenarios. In this work, we focus on urban scenarios, where mobility of vehicles is low with respect the vehicles' transmission range. In ref. [10], the authors identify three models for data dissemination in VANETs, such as push, pull, and hybrid. The main difference between push and pull policies is that in pull techniques the messages are generated on the demand from the source vehicle, while in push techniques the messages are generated periodically. In this work, we focus on pull techniques, which require lower overhead. Another classification can be found in [11], where the techniques are categorized as forwarding based dissemination, broadcast based dissemination, push based dissemination, routing protocols based dissemination, and other dissemination mechanism. In forwarding algorithms, vehicles use techniquessuch as data aggregation and utility functions to determine the suitability of the retransmission of a message. Broadcast algorithms refer to the broadcast procedure used to disseminate the information, which is different with respect to the unicast mechanism used by routing based dissemination approaches. Regarding push based algorithms, they employ a dissemination policy considering the target application to determine the potential recipients of the messages. Regarding this work, the proposed approach is related to broadcast based dissemination using a utility function based on dissimilarity metrics. Furthermore, there are available other seminar works on broadcasting for multi-hop networks that can be also applied to VANET scenarios. In ref. [11], the authors present a comprehensive survey on broadcast approaches for ad hoc networks. It describes broadcasting techniques that can be used in VANETs, such as counter-based approaches, area-based approaches, and neighbor knowledge approaches. In counter-based approaches, nodes counter the number of messages received as a local estimator of the local density of nodes. This metric is used for adjusting the nodes' retransmission probability. In area based-approaches, nodes only retransmit incoming messages towards target areas. In neighbor-knowledge approaches, nodes determine the relationship among nodes to determine graph theory properties, such as connected dominant set (CDS) and self-pruning strategies. Many variables have been used to determine the potential forwarding nodes in data dissemination algorithms in multi-hop network.