## 3 Results
### Case Analysis
In the experiment, the total demand was 28 blocks, with the total price of $4076.81 million at the first round. This implies that, if the initial bidding price (i.e., the minimum bidding price) is too high, the Conservative bidder may not have an opportunity to attend the auction. In fact, this intimidates the fairness of the auction, which was designed to allocate the spectrum blocks without causing adversary impact on the existing mobile telecommunication market [26]. Moreover, if there is no chance for the Conservative bidder, and due to the high minimum bidding price everything is predetermined, there is no reason to have an auction. Note that, in this situation, the allocation results were already finalized at the beginning of the auction. Thus, although the total price of the auction is higher than that of the low price case, it is better to identify an appropriate minimum bidding price that can give fair opportunities to all existing IMT service providers.  
To identify the best minimum bidding price at the first round, the optimization model mentioned in Section 2.3.4 was applied. As mentioned in the second case, when the minimum price is too high (i.e., 20% of the total annual revenue), the Conservative bidder cannot have an equal opportunity at the beginning of the auction. To resolve this issue, in this case, we assume that the round with the final decision should be between 6 and  
Figure 11: Bidding price over multiple rounds at Stage 1 (low price case with demand reduction policy).  
Figure 12: Number of spectrum blocks over multiple rounds at Stage 1 (low price case demand reduction policy).  
50 rounds (i.e., \(\varphi_{min}=6\) and \(\varphi_{max}=50\) in Equation (13)), and \(\tau_{min}=\$1019.20\) million and \(\tau_{max}=\$4076.81\) million in Equation (12). Figure 15 shows the result of the optimization with a meta-heuristic algorithm in OptQuest\({}^{\text{\textregistered}}\) 9.1.2 software.  
The best minimum bidding price was $2386.81 million (i.e., $885.24 million per block). The auction was ended at the 7 th round with the price of $2434.94 million at the first stage. Figure 14: Number of spectrum blocks over multiple rounds at Stage 1 (high price case). Figure 15: Scenario comparison between the final bidding prices under various minimum bidding prices. Figure 13: Bidding price over multiple rounds at Stage 1 (high price case). Note that the minimum bidding price at the IMT spectrum auction in 2018 in South Korea was $2348.76 million (see Section 2.3). The difference between the two values was only 1.62% from $2348.76 million. Regarding the level of significance (\(\alpha=0.05\)) associated with statistical estimation from the proposed simulation model and the final contract price of $416.20 million. Regarding Type 3 offering 10 blocks with a bidding price of $02434.94 million (or $416.20 million. Regarding Type 3 offering 10 blocks with a bidding price of $12348.76 as the minimum bidding price. As mentioned earlier, the spectrum auction in South Korea was designed to provide a fair opportunity to all existing IMT companies. This is because the government agency should maintain liberalization of the IMT market (i.e., no sudden change in the market due to the IMT auction designed by government agency). In this sense, the proposed approach can contribute to identifying the best minimum bidding price for healthy and fair competition in the IMT market.