# Intersection-Based Link-Adaptive Beaconless Forwarding in Urban Vehicular Ad-Hoc Networks
## 5 Conclusions  
Receiver-based data forwarding protocols are well suited to enable remote monitoring applications in urban VANETs. However, they often result in high ETE delay due to frequent relay selection process performed for every data packet. Although the existing work has focused on alleviating this issue by allowing the relay vehicle to stay as a default forwarder for certain duration, the latter duration is not accurate enough since it does not consider various aspects of urban traffic such as the presence of road intersections and drastic speed decay in vehicles. This article proposes a receiver-based data forwarding protocol called ILBFC that makes use of geographic information of road intersections to effectively decide the duration for which a relay vehicle will stay as a default forwarder. Additionally, a winner relay management scheme is used to check the validity of relay vehicle acting as a default forwarder on every data packet reception. This is based on the relative geographic progress of current and previous relay vehicles towards destination. The performance of ILBFC has been compared with LBF, DBD and BLR, in terms of PDR, average ETE delay and PRC for three different scenarios. The simulation results highlight the performance improvement of ILBFC over LBF, DBD and BLR in terms of PDR, average ETE delay and PRC. This is due to the effective link duration computation of ILBFC which is based on the position coordinates of the upcoming road intersection. Also, ILBFC is equipped with a better winner relay management scheme that reduces the frequency of relay selection process while also taking into account the drastic speed decay in vehicles. In case of PRC performance, BLR offers highest unicast efficiency (implying low PRC) as it performs relay selection process on every data packet reception. However, this comes at the expense of poor PDR performance, which is one of the drawbacks of frequent relay selection and is caused due to buffer overflow. Specifically, the range of PDR performance losses in BLR when compared to ILBFC is between 9-11% for all the three cases. On the other hand, ILBFC offers relatively lower PRC (implying higher unicast efficiency) when  
Figure 7: Performance comparison of ILBFC with LBF, DBD and BLR versus maximum node velocity while keeping the source transmission rate equals 400 kbps and the number of nodes equals 40 (cont.). (**a**) PDR versus maximum node velocity; (**b**) Average ETE delay versus maximum node velocity; (**c**) PRC versus maximum node velocity. compare to LBF and DBD while also giving superior PDR and average ETE delay performance than the rest. Overall, ILBFC provides an efficient and reliable routing solution to enable remote monitoring applications over urban VANETs. In future work, further simulations under several complex urban scenarios will be carried out to analyze the performance of ILBFC. Also, ILBFC will be extended to provide routing solutions to applications involving mobile destination in urban VANETs. This would require periodic updates from destination vehicle informing other vehicles about its current location. In addition, this may also need the source and other relay vehicles to make use of tracking mechanism to estimate the latest location of the destination vehicle. Apart from this, various physical characteristics of the wireless environment such as signal strength and interference will be incorporated in the relay selection process of ILBFC and their impact will be thoroughly analyzed. [PERSON] and [PERSON] contributed to the main idea and the methodology of the research. [PERSON] designed the experiment, performed the simulations and wrote the original manuscript. [PERSON] contributed significantly in improving the technical and grammatical contents of the manuscript. [PERSON] and [PERSON] reviewed the manuscript and provided valuable suggestions to further refine the manuscript.