The search space design for enhanced Downlink Control Channel in LTE-advanced system

Enhanced Physical Downlink Control Channel (EPDCCH) is one of the most important technical improvements in 3GPP LTE-Advanced standards with respect to the new nonuniform network deployments. Frequency diversity as well as frequency selective scheduling gain together with beamforming gain is expected. In order to achieve frequency scheduling gain, the search space of EPDCCH should contain subcarriers associated with good channel quality. In this paper, we propose a modified search space mapping scheme that maximizes the frequency scheduling gain with given frequency resource. Simulation results shows proposed search space function is effective in improving the EPDCCH performance under frequency selective fading channels. Up to 5 dB signal-to-noise ratio (SNR) gain is observed compared with existing search space function.