 |
Next, I¡¯d like to explain second metric in the priority determination. The second metric is the intersection relay index (IRI).
In SIGO, we add the metric that preferentially selects the intersection node as a relay node to minimize the effect of shadowing.
The following procedures calculate IRI, which gives priority to the street intersection node.
The step1 is Selection of the closest road segment.
To calculate IRI, the transmitting node (relay node or the source node) selects one of the road segments closest to the destination node among the road segments where relay candidate nodes exist.
The center coordinate of each road segment was used to calculate the distance between the destination node and road segment.
The transmitting node is relay node or the source node.
An example is shown in this Figure.
In this example, the road segment closest to the destination node is enclosed by the dashed blue line in the figure.
The step2 is Calculation of the transmission probability Rp in a selected road segment.
rp(t) is the expected transmission probability of the relay candidate node p in the road segment closest to the destination node.
N represents the number of candidate nodes in the road segment closest to the destination node.
The expected transmission probability was calculated using the same method as the previous slide.
The final step is calculation of the IRI, using ¥è, Rp.
The ¥èi is the angle between the lines connecting the transmitting node to the destination node and connecting the transmitting node and the intersection node i.
The higher ¥èi and the lower Rp, the higher the IRIi as shown in this equation.
this aims that the node in the selected road segment can receive the packet highly probability by the intersection node¡¯s relaying when Rp is small.
In addition, since the local optimum problem occurs when ¥è is large, there is also the aim that actively selecting of the intersection node as a relay candidate node to prevent this. |
IEEE/ICACT20220087 Slide.14
[Big Slide]