Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Particle swarm optimization for pilot tones design in MIMO-OFDM systems | Seyman and Tajpinar EURASIP Journal on Advances in Signal Processing 2011 2011 10 http content 2011 1 10 o EURASIP Journal on Advances in Signal Processing a SpringerOpen Journal RESEARCH Open Access Particle swarm optimization for pilot tones design in MIMO-OFDM systems Muhammet Nuri Seyman1 and Necmi Ta pinar2 Abstract Channel estimation is an essential task in MIMO-OFDM systems for coherent demodulation and data detection. Also designing pilot tones that affect the channel estimation performance is an important issue for these systems. For this reason in this article we propose particle swarm optimization PSO to optimize placement and power of the comb-type pilot tones that are used for least square LS channel estimation in MIMO-OFDM systems. To optimize the pilot tones upper bound of MSE is used as the objective function of PSO. The effects of Doppler shifts on designing pilot tones are also investigated. According to the simulation results PSO is an effective solution for designing pilot tones. Keywords MIMO-OFDM channel estimation particle swarm optimization Introduction Recently to meet the demand on high data rate transmission in communication systems orthogonal frequency division multiplexing OFDM is applied as a modulation scheme. OFDM is a multicarrier modulation technique that operates with specific orthogonality constraints between subcarriers. The orthogonality results a waveform which uses available bandwidth with a high bandwidth efficiency 1 . Also OFDM can be combined with multiple transmit and receive antennas known as multiinput multi-output MIMO architecture to improve system capacity and quality of service 2 . However at the receiver MIMO-OFDM systems require channel state information CSI for coherent demodulation and data detection. In order to obtain CSI blind and training symbol pilot tones -based channel estimation techniques are applied. In blind channel estimation technique CSI is estimated by channel statistics .
