With advance of wireless communications, our life style has been changed. We can
connect not only Internet service at anytime anywhere, but also get real time contents
service like TV show and VOD (Video On Demand) without delay. Shortly, our society
has been full of communications with electrical devices. The market of communication
service is getting wider and more complicated. Wire communication only can not meet
the consumer`s demands so there are many research projects to improve the wireless
communication technologies. Nontheless, in wireless communication systems, it is precise
that we have only limited amount of resources. This fact makes a trade-o between reuse
frequency and inter-cell interference is very important and many research centers and
companies are focus on development the most ecient way between interference and
reuse the resources. Femtocell is a promising solution for this problem. To improve the
system capacity, the small cell concept which by getting the transmitter and receiver
closer to each other, low power and more bandwidth reuse system is emerged.
In LTE-Advanced system, with the femtocell system, total capacity improvement is
expected and to expand the bandwidth carrier aggregation (CA) technique is applied.
Carrier aggregation technique makes wider bandwidth when the user want higher data
rate in multi carrier environment.
In other words, in this system, component carriers (CCs) allocation is very important
to use the resource e ectively, and the reuse resources meet to achieve a higher data rate,
but it makes severe interference to other cells which use the same frequency bands. In
addition, limitation such as unpredictable deployment of femtocells and limited number
of component carriers require a rational solution.
In this thesis, we propose a load-based component carrier selection scheme which can
manage interference between femtocell and femtocell and allocate resources eciently by
means of manage the CCs allocation in femtocell networks. We enhanced the Primary
Component Carrier selection and Secondary Component Carrier selection procedures and
considered the cell load for all steps. Simulation results demonstrate that the proposed
scheme improve total system capacity.
통신기술의 눈부신 발전으로 과거에 상상으로만 여겨졌던 기술들이 차츰 현실에서 실현이 되고 있다. 불과 10여년 전만 하더라도 컬러 핸드폰이 막 상용화되고 16폴리의 전화벨을 사용하는 핸드폰이 최신이었지만, 지금은 스마트폰이라 불리는 신형 장비의 발전으로 다양한 정보와 즐거움을 누구나 손쉽게 사용할 수 있을 뿐 아니라, 간단히 쇼핑, 버스나 기차 예매등 실생활에 더더욱 밀접하고 편리한 서비스를 제공해주고 있다. 하지만 이런 발전속에서도 우리는 여전히 무선 통신의 주 자원인 주파수의 부족이라는 고질적인 문제점을 가지고 있다. 이러한 제한된 문제점을 해결하기 위해 우리는 소형셀 기술 즉 펨토셀과 같은 자그마한 셀을 상용화 함으로서 주파수 재사용율을 높임으로 주파수 제한을 극복하려 하였고, 이런 제한된 환경에서 캐리어 어그리게이션 기술을 통하여 그 상황에 맞게 가용주파수를 통합함으로서 효율성을 극대화할 수 있게 되었다.
