• Journal of Communications and Networks
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• 제8권4호
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• pp.442-450
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• 2006

Inter-operability between heterogeneous radio access technologies (RATs), in the sense of seamless vertical han-dover (VHO) support with common radio resource management (CRRM) functionalities, has recently attracted a significant research attention and has become a prominent issue in standardization fora. In this paper, we formulate the problem of load balancing between cooperative RAT's as a mathematical program and by trading off a pre-defined delay tolerance per request we propose a vertical handover batch processing (VHBP) scheme. To quantify the performance of the proposed VHBP scheme we compare it with a baseline processing scheme, where each VHO request is processed independently under a number of different network scenarios. Numerical investigations reveal significant net benefits of the proposed scheme compared with the baseline, both in terms of achieved load balancing levels but also with regard to the acceptance rate of the VHO requests.

• 한국통신학회논문지
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• 제36권8B호
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• pp.910-920
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• 2011

다양한 무선 기술이 증가함에 따라 이기종 네트워크 환경은 여려 우선 기술들이 중첩 되어 공존하는 환경으로 변화되고 있다. 이렇게 혼재하여 공존하는 여러 우선 네트워크들의 효율적인 관리를 위해 통합자원관리 방안(Common Radio Resource Management: CRRM)이 제안되었다. 통합자원관리 방안은 중첩되어 존재하는 다양한 이기종 네트워크들의 자원을 하나의 자원과 같이 통합적으로 관리하는 방안이다. 다양한 네트워크가 중첩되어 존재하고 네트워크에 따른 우선 서비스의 종류도 증가함에 따라 CRRM에서 다양한 네트워크들의 통합적인 자원관리를 위해서는 고려해야 할 사항이 더욱 증가하게 된다. 본 논문에서는 여러 가지 고려요소를 바탕으로 최적의 선택을 결정하는 다기준 의사 기법의 하나인 Analytical Network Process (ANP)를 사용해 통합자원관리 방안을 제안하였다. 또한 본 논문에서는 우선 환경에서 널리 사용되고 있는 Adaptive Modulation and Coding (AMC)를 고려하여 채널 상태 (channel condition) 에 따라 할당되는 대역폭 모델을 제안하였다. 시뮬레이션에서는 자원관리시에 고려될 수 있는 다양한 요소를 적용하여 고려하는 요소에 따라 최적의 자원관리가 적용됨을 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권10호
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• pp.4015-4033
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• 2015

The future mobile networks consist of hyper-dense heterogeneous and small cell networks of same or different radio access technologies (RAT). Integrating mobile networks of different RATs to provide seamless and smooth mobility service will be the target of future mobile converged network. Generally, handover from high-speed networks to low-speed networks faces many challenges from application perspective, such as abrupt bandwidth variation, packet loss, round trip time variation, connection disruption, and transmission blackout. Existing inter-RAT handover solutions cannot solve all the problems at the same time. Based on the high-layer convergence sublayer design, a new receiver-aided soft inter-RAT handover is proposed. This soft handover scheme takes advantage of multihoming ability of multi-mode mobile station (MS) to smooth handover procedure. In addition, handover procedure is seamless and applicable to frequent handover scenarios. The simulation results conducted in UMTS-WiMAX converged network scenario show that: in case of TCP traffics for handover from WiMAX to UMTS, not only handover latency and packet loss are eliminated completely, but also abrupt bandwidth/wireless RTT variation is smoothed. These delightful features make this soft handover scheme be a reasonable candidate of mobility management for future mobile converged networks.