본 연구는 유선망, 이동통신망, 그리고 인터넷 전화의 착신접속료가 현행 장기증분비용플러스방식에서 순수장기증분비용방식과 무정산방식으로 변화될 경우 사회후생이 어떻게 변화할 것인가를 간단한 산식 모형을 사용하여 분석한다. 본 연구에서는 EC(2016) 모형을 활용하여 2015년도에 순수장기증분비용방식과 무정산방식이 적용되었을 때의 사회후생을 측정하고 도입전과 사회후생을 비교하였다. 분석결과 다음의 결과를 얻었다. 첫째, 순수 LRIC 도입과 무정산 방식 도입은 현행 장기증분플러스방식 적용시 보다 소비자 후생과 사회후생을 증가시킨다. 순수 LRIC와 무정산 방식은 현행보다 접속료를 낮추며, 이는 소매요금의 인하를 가져온다. 둘째, 순수 LRIC 도입과 무정산 방식 도입은 현행 장기증분플러스방식 적용시 보다 생산자 잉여를 감소시킨다. 소매요금의 인하는 가격탄력성이 1이상이 되지 않는 이상 소매부문 매출액을 줄인다. 셋째, 네트워크별 영향을 보면, 소비자 후생 증가와 생산자 잉여 감소는 이동망, 유선망, 인터넷 전화망순이다. 사회후생 증가는 이동망, 인터넷전화망, 유선망 순이다. 이동망은 생산자 잉여의 감소가 가장 커지만 소비자 후생의 증가폭이 훨씬 커기 때문에 전체 사회후생증가가 제일 크다. 유선망의 사회후생이 감소하는 이유는 생산자 잉여감소가 소비자 후생 증가보다 커기 때문이다. 반면 인터넷전화망은 생산자 잉여가 감소되지도 않으며 소비자 후생 또한 증가한다. 넷째, 순수 LRIC에 비해 무정산의 사회후생 효과가 더 크다는 것을 알 수 있다. 이는 접속료 인하가 많으면 많을수록 사회후생은 증가한다는 것을 알 수 있다. 다섯째, 한계비용 크기에 따라 사회후생효과는 달라지며, 한계비용 즉 순수 LRIC 값이 작으면 작을수록 사회후생의 증가는 더 커진다는 것을 알 수 있다. 순수 LRIC 시행초기에는 한계비용이 커서 사회후생 증가가 적을 수는 있지만 향후에는 순수 LRIC 즉 한계비용이 줄어들기 때문에 사회후생은 더욱 더 커질 수 있다.
Interconnection between telecommunication networks is essential for subscribers to communicate with subscribers belong to another network. Therefore, termination facilities necessary to access is treated as bottleneck facilities and termination access charges that network owner levy on network user has been regulated so far. However, how to set access charges has been the subject of intense controversy for more than a decade now. According to the prevailing theory, while competition between networks tp attract new customers may be fierce, in the absence of regulation they will still charge monopoly-level prices to other networks for terminating calls to their subscribers. Once a consumer subscribes to a particular mobile firm, callers on fixed telephone and mobile networks must send their calls to that subscribers chosen network. No matter how competitive the market for network subscribers may be, a mobile network holds a monopoly over, and can charge high prices for, delivering calls to its own subscribers. Concerns about telephone network call termination being a bottleneck service, and a history of high termination charges, led to termination access charges being regulated, and they have since been subject to price controls in every country in the European Union, and in numerous other countries around the world. What is important is how termination access charges is regulated. Other country around world, termination access was pricing at LRIC. In 2009, EC(2009a) proposed dramatic reductions in mobile access charges, and Ofcom subsequently published a consultation document (Ofcom(2009a)) considering the pros and cons of three alternative approaches to regulating Mobile Termination Rates. These were: (i) pricing at pure long-run incremental cost(pure LRIC), broadly the approach recommended by the EC; (ii) imposing reciprocity with fixed networks, i.e. setting mobile termination charges to match the regulated rates of fixed-line network operators, as practised in the USA; and (iii) adopting Bill & Keep (B&K), which would effectively abolish mobile termination charges by setting them equal to zero. By pure LRIC, termination access charges is lower than LRIC +. This is because LRIC + recovers common cost where as pure LRIC does not. Therefore, as more countries introduce pure LRIC, it is meaningful to analyze the effect of introducing pure LRIC based termination access charges on consumer surplus and social welfare. So far, studies about social welfare effect of regulating termination access charge is rare, although studies about optimal access charges maximizing social welfare are many. This paper presents the computation model about consumer surplus, producer profit, and social welfare. Then, welfare effects of reducing access charges based on pure LRIC and Bill and Keep. The change of access charges affects retail price and change of retail price affects consumer surplus through the change of outgoing traffic. Also, producer surplus is influenced by access charge, retail price, and outgoing incoming traffic. The results of the analysis show that firstly, pure LRIC and Bill & Keep increase consumer surplus and social welfare, and decrease producer surplus. Secondly, social welfare in mobile network is most increased. This is because in mobile network, the increase of consumer surplus offsets the decrease of producer surplus than other networks. Thirdly, Bill & Keep increase social welfare more than pure LRIC. This is because retail price is not determined by competitive markets and gets some margin form access charge. Fourthly, Social welfare effects depends on the size of marginal cost. That is, the increase of social welfare is higher as pure LRIC is lower. This paper shows that it is desirable to introduce pure LRIC or Bill & Keep instead of LRIC + to increase social welfare.