# A Cooperative Communication Protocol for QoS Provisioning in IEEE 802.11p/Wave Vehicular Networks
## 3 Related Works
In [31], the authors proposed a speed wave forecasted routing algorithm combined with speed fluctuation forecasted and computation of the movement domain to improve the GPSR greedy algorithm. The algorithm uses the vehicle speed and position to find relatively stable links, which is based on the forecast of the speed fluctuations. In [32], the authors proposed a long lifetime any paths routing protocol providing stable communication paths. The algorithm addressed the problem of stability of any path communications in vehicular ad hoc networks in the presence of inter-vehicle link failures associated with vehicle mobility. In [33], the authors proposed a MOving-ZOne-based (MoZo) architecture. The MoZo consists of multiple moving zones that group vehicles based on the movement similarity. The selected CH is responsible for managing information about CMs as well as the forwarding packets. However, these studies are routing protocols that do not conform to the WAVE standard because they do not consider the WAVE standard. In [34], the authors proposed an interference-aware relay selection to select the best relay by using inter-node interference and channel statistics. In [35], the authors investigate the issues and challenges in designing an efficient cooperative MAC scheme for multi-hop wireless networks. In [36], the authors proposed a distributed power allocation to limit the overall interference and improve the network performance. In [37], the authors presented an analytical approach to describe the energy saving zone between a communicating pair, where a relay located inside this zone is energy efficient. Using this concept, they proposed a stochastic geometry method to estimate the energy saving gain introduced by relay-assisted D2D communication. In [38], to minimize the effect of interference at the different receivers, the authors proposed a simple opportunistic relay strategy to identify those relays providing a limited contribution to the interference. These algorithms focused on reducing interference or energy consumption. In addition, they did not consider the vehicular network environment with high mobility. In [39], the authors proposed a dynamic-changing interval framework for the WAVE system. This scheme can shorten the transmission delay of safety messages. In [40], the authors proposed a multi-channel MAC scheme to archive high bandwidth utilization and avoid a multi-channel hidden terminal problem. In [41], the authors proposed a QoS guaranteed channel access scheme for V2V communication based on the 802.11p protocol to adjust the priority of real-time streaming to avoid collisions. However, these studies did not consider multi-hop transmission. In [42], the authors evaluated the delays and the packet delivery ratio in WAVE standard by simulation for the vehicle-to roadside link and proposed the multi-hop data delivery scheme in WAVE standard. However, this scheme did not consider the congestion by vehicle density and relay selection by the link status. Therefore, we propose a new cooperative communication scheme that can be applied to the WAVE standard. The proposed scheme can improve the reliability and connectivity of the WAVE communication system and can provide the network QoS.