Interference Rejection Characteristics by Adaptive Array at User Equipment Using Measured K-Factor in Heterogeneous Networks

Kentaro NISHIMORI  Keisuke KUSUMI  Misaki HORIO  Koshiro KITAO  Tetsuro IMAI  

IEICE TRANSACTIONS on Communications   Vol.E96-B    No.6    pp.1256-1264
Publication Date: 2013/06/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E96.B.1256
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Heterogeneous Networks for Future Cellular Systems)
heterogeneous networks,  adaptive array,  user equipment,  K-factor,  zero forcing,  

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In LTE-Advanced heterogeneous networks, a typical cell layout to enhance frequency utilization is to incorporate picocells and femtocells in a macrocell. However, the co-channel interference between the marcocell and picocell/femtocell is an important issue when the same frequency band is used between these systems. We have already clarified how the interference from the femto(macro) cell affects on the macro(femto) cell. In this paper, we evaluate the interference rejection characteristics by an adaptive array with user equipment (UE). The characteristics are evaluated based on the K-factor used in the Nakagami-Race Fading model and the spatial correlation that is obtained in an actual outdoor environment. It is shown that a two-element adaptive array at the macro UE (M-UE) can sufficiently reduce the interference from the femto base station (F-BS) to the M-UE even if the number of total signals exceeds the degrees of freedom of the array.