earticle

영어

This paper presents cell configuration strategies for orthogonal frequency division multiple access (OFDMA) based hierarchical cellular systems (HCS). We consider two cases: the symmetric case that HCS is used to extend the data rate coverage and the asymmetric case that HCS is applied to cover the hot spot. We formulate the cell configuration strategy problem with spectral reuse planning and channel allocation constraints, and suggest solutions for each case. The numerical results show that HCS can improve the system stability in the symmetric case and enhance the system performance about two times rather than that of the conventional cellular system, when the hot spot is created at the macro-cell edge in the asymmetric case. In addition, we describe that the co-channel interference from macro-cell base stations (BSs) are the dominant factor of system performance, but that from microcell, BSs can be negligible.