Patent ID: 8189696
Filing Date: 2012-05-29
Classification: H04B,H04L

Abstract:
1. An Orthogonal Frequency Division Multiplexing (OFDM) system using a Spatially Layered transmission Mode (SLM), the system comprising: a reference relay station configured to perform an SLM process by modulating a phase and magnitude of a signal by using a predetermined modulation order suitable for the reference relay station to obtain a spatially-layered signal and configured to transmit the spatially-layered signal to a mobile station; a cooperative relay station configured to perform the SLM process by modulating a phase and magnitude of a signal by using a predetermined modulation order suitable for the cooperative relay station to obtain a spatially-layered signal and configured to transmit the spatially-layered signal to the target mobile station; a base station configured to select the reference relay station and the cooperative relay station among a plurality of relay stations and configured to transmit data to the selected reference relay station and the cooperative relay station; and the mobile station configured to detect data through Maximum Likelihood (ML) detection in which a signal having the largest ML is detected by comparing the received spatially-layered signal with a signal which is converted through the SLM after being subjected to a predetermined coding operation, upon receiving the spatially-layered signal from the reference relay station and the cooperative relay station, wherein the reference relay station and the cooperative relay station are selected according to a distance from the mobile station to each relay station and a channel quality between the mobile station and each relay station, wherein the base station selects the reference relay station closest in distance to the mobile station and having a best channel quality, and selects the cooperative relay station second closest to the mobile station and having a second best channel quality.