Author/Authors :
KURNAZ, Çetin Ondokuz Mayıs Üniversitesi - Mühendislik Fakültesi - Elektrik-Elektronik Müh Bölümü, Turkey , KORUNUR ENGİZ, Begüm Ondokuz Mayıs Üniversitesi - Mühendislik Fakültesi - Elektrik-Elektronik Müh Bölümü, Turkey , GÖKALP, Hülya Ondokuz Mayıs Üniversitesi - Mühendislik Fakültesi - Elektrik-Elektronik Müh Bölümü, Turkey , SEZGİN, Hatice Ondokuz Mayıs Üniversitesi - Mühendislik Fakültesi - Elektrik-Elektronik Müh Bölümü, Turkey
Title Of Article :
Relating the Optimum Pilot Bit Spacing to Channel Parameters in Orthogonal Frequency Division Multiplexing Systems
Abstract :
In this study, the effect of pilot bit arrangement on Orthogonal Frequency Division Multiplexing (OFDM) system with comb type channel estimator performance is investigated by using computer simulations. Radio propagation data that obtained in Manchester city center are used in the simulations. The estimation of channel at pilot subcarriers is done by least square (LS), and interpolation of channel at data subcarriers are obtained by low pass interpolation. The pilot ratio (ratio of pilot bits to data bits) that gives the lowest bit error rate is determined as the Optimum Pilot Ratio (OPR) and spacing between the pilot sub-carriers as (Δf)OPR. It is seen from the results that the OPR changes depending on channel profile and the number of sub-carriers but frequency spacing between the optimum pilot bits remains the same. Therefore it is concluded that (Δf)OPR can be related to channel frequency selectivity. Then the relation between (Δf)OPR and channel parameters is investigated. The results show that (Δf)OPR can be related best with coherence bandwidth at 0.9 correlation. Therefore 1.4 pilot symbols per Bc,0.9 can be used.
NaturalLanguageKeyword :
OFDM , channel estimation , optimum pilot rate , mobile radio channel , coherence bandwidth.
JournalTitle :
Uludağ University Journal of The Faculty of Engineering
