Two-hop Relay-based Vehicular Network in WiMAX
International Journal of Computer Applications
In mobile communication, routing data through intermediate mobile node is a challenging task due to high mobility of nodes which causes rapid change in network topology and frequent disconnection between pair of nodes. To address these issues, Mobile Relay Station (MRS) is introduced into the network based on IEEE 802.16j standard. The MRS features are similar to the Fixed Relay Station (FRS), however the MRS has capability to move as Mobile Station (MS). In intermittent connection, by adapting
... ection, by adapting the features of Delay Tolerant Network (DTN), the MRS can store and carry the data until it find the destination to forward the data. Assuming that MS is aware of its' own movement as well as its closest neighbor nodes. In this paper, Dynamic Routing Algorithm (DyRA) has been proposed to select next hop node towards the destination. The forwarding decision is based on a computed metric which is a combination of Packet Reception Rate (PRR), Link Expiration Time (LET) information and Number of Slots (NoS) available at the candidate MRS nodes. Also, the proposed Relay-based Vehicular Network (RVN) in WiMAX using cross layer design (CLD) is designed to select the optimal next hop node and set new route when current routing path is no longer available. The preliminary results for system throughput performance and average end-to-end delay are analyzed. The results show that by deploying relay-based in vehicular network can enhance system throughput in terms of packet loss ratio (PLR), packet delivery ratio (PDR), and average end-to-end (ETE) delay. NCTUns simulation environment has been used to study the mobile node performance. General Terms Routing, Vehicular network, WiMAX. Packet Delivery Ratio (PDR): The number of packet received over the number of packet transmitted. Packet Loss Ratio (PLR): The number of packet loss over the number of packet transmitted. As shown in Fig 9, it can be seen that light traffic does not give any big impact to PLR performance since it remains around 0.09 to 0.15 as the traffic load increases. However, heavy traffic which is above 2.0 Mbps, give significant impact to PLR performance. Heavy traffic load caused many packets to be generated per second. Since each user had limited available slots, there are several packets need to be queued before transmission. Note that the chance of dropping packets higher in heavy traffic. Thus, increases PLR of one-hop and two-hop communication as the traffic load increases. As observe in Fig 9, the PLR result shows that two-hop communication outperformed one-hop communication as the traffic load increases. If Direct link between BS-MS is chosen If RS is chosen to be the medium between BS-MS connection 7 Fig 9: Impact of varying traffic load on the PLR. The PDR output is shown in Fig 10. It can be seen that light traffic does not give any big impact to PDR performance since it remains around 0.85 to 0.91 as the traffic load increases. However, heavy traffic which is above 2.0 Mbps, give significant impact to PDR performance. We can see that as the traffic load increases, the PDR is decrease. Injecting more packets into the network causes the dropping of many of the stored packets. Therefore, the PDR of one-hop and two-hop communication is decreased. However, two-hop communication shows better PDR than one-hop communication as the traffic load increases.