Browsing by Author "Basar, Ertuğrul"

Now showing 1 - 3 of 3

Citation Count: 2
Generalized LED Index Modulation Optical OFDM for MIMO Visible Light Communications Systems
(IEEE, 2016) Basar, Ertuğrul; Panayırcı, Erdal; Uysal, Murat; Haas, Harald
In this paper we propose a generalized light emitting diode (LED) index modulation scheme for multiple input multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) visible light communications (VLC) systems. The proposed scheme generalizes the LED index modulation concept by using the spatial multiplexing principle to transmit complex OFDM signals through VLC channels by separating these signals into their real-imaginary and positive-negative parts. The maximum a posteriori (MAP) estimator of the proposed scheme which relies on quadratic programing (QP) problem is presented for flat VLC channels. It is shown via computer simulations that the proposed scheme achieves considerably better error performance than the existing VLC-MIMO-OFDM systems due to its power efficiency and improved transceiver structure.
Citation Count: 1
A New Technique for OFDM: OFDM-Index Modulation
(IEEE, 2013) Basar, Ertuğrul; Aygölü, Ümit; Panayırcı, Erdal
In this study a novel scheme called orthogonal frequency division multiplexing with index modulation (OFDMIM) is proposed for frequency selective channels. In this scheme the information is conveyed not only by only M -ary signal constellations as in classical OFDM but also by the indices of the active subcarriers which are determined according to the information bits. Different transceiver structures have been investigated for the proposed scheme and it has been shown via computer simulations that OFDM-IM system achieves significantly better error performance than the classical OFDM.
Citation Count: 135
Performance of spatial modulation in the presence of channel estimation errors
(IEEE-INST Electrical Electronics Engineers Inc, 2012) Basar, Ertuğrul; Aygölü, Ümit; Panayırcı, Erdal; Poor, H. Vincent
This work investigates the negative effects of channel estimation errors on the performance of spatial modulation (SM) when operating over flat Rayleigh fading channels. The pairwise error probability of the SM scheme is derived in the presence of channel estimation errors and an upper bound on the average bit error probability is evaluated for M-PSK and M-QAM signalling. It is shown via computer simulations that the derived upper bound becomes very tight with increasing signal-to-noise ratio (SNR) and the SM scheme is quite robust to channel estimation errors.