IMPACT OF THE RATIO OF THE COST OF BS TO RS ON SOLUTION

It is also worth to notice how the ratio of the cost of BS and RS affects the site selection. Intuitively, as the ratio raising, the RS becomes relatively cheaper, so it should tend to select more RS compared to the BS and connections from TP to RS should increase. Figure 1 shows the trend. It shows number of connections between TP and BS and between TP and RS as the cost ratio varying from one to ten, i.e., from the cost of BS equals to the cost of RS to the cost of BS ten times the cost of RS. Figure 2 shows the corresponding average path loss between each TP and its communicating node. It can be seen that the path loss is decreasing which means the quality of the radio received becomes higher as the cost of RS becoming lower.

Figure 1: Average path loss between each TP and its communicating node as the ratio of the cost of BS and RS is varied.

Figures 2 and 3 show two extreme cases. In both cases, the number of candidate BS sites is 50, the number of candidate RS sites is 150, and the number of TP is 500. Figure 2 shows the plan of the cost of BS equals to the cost of RS. In this case, there are 38 BSs and 50 RSs being selected; 177 connections between TP and BS; 320 connections between TP and RS. Figure 3 shows the plan of the cost of BS ten times to the cost of RS. In this case, there are 28 BSs and 75 RSs being selected; 133 connections between TP and BS; 367 connections between TP and RS.

Figure 2: An output of the planning tool when the ratio of the cost of BS and RS is 1.

Figure 3: An output of the planning tool when the ratio of the cost of BS and RS is 10.