An Inter-Cell Interference Cancellation Method for OFDM Cellular Systems Using a Subcarrier-Based Virtual MIMO

In this paper, a new method of inter-cell interference (ICI) cancellation in the downlink is proposed for users at the cell boundary in OFDM-based cellular systems, by using the concept of a subcarrier-based virtual multiple-input multiple-output (SV- MIMO) where multiple antenna techniques are performed on a set of subcarriers, not on the actual antenna array. In the proposed SV-MIMO, "subcarrier signatures," obtained at the mobile station (MS) with a single antenna, are exploited to separate the desired signal from ICIs. The concept of a virtual signature randomizer (VSR) is introduced to improve channel separability in the SV-MIMO approach. Also, the concept of a virtual smart antenna, in which the steering vector is formed by a set of subcarriers with the estimated symbol timing offset (STO) between BSs, is compared with conventional ICI reduction methods. It is shown by simulation that the proposed method is effective in reducing ICI and inter-sector interference for fully- loaded OFDM cellular systems with a frequency reuse factor equal to 1, compared with conventional methods.