Deployment of multi-input multi-output antenna systems with orthogonal frequency division multiplexing (OFDM) over wireless channels has been identified as one of the most promising techniques to support high-performance and high data rate communication for future wireless broadband services. This paper first highlights common space-time coding (STC) schemes used in wireless communication systems. The paper further reviews the deployments of these STC schemes over frequency selective fading channels with OFDM signalling through which there is coding over the space, time, and frequency domains.
This paper presents the experimental results of a study on radio frequency attenuation path loss conducted in Ekiti State, Nigeria. The objective of the study is to develop a path loss model comparable to the existing path loss models through a real time application of outdoor VHF signal propagation measurements of the Nigeria Television Authority (NTA) Channel 5 and carrier frequency of 175.25 MHz located in Ado-Ekiti, Ekiti State, Nigeria. Experimental measurements were taken in three routes covering the entire state. Analysis of the data collected from the experiments resulted in models which are in agreement with the existing standard models. Root Mean Square Errors were calculated for all the path loss models. Results show that the signal of the station was generally poor along the routes considered as the deviations of the measured path losses from the free space path loss exceed 6 dB in most cases.
<!--?xml:namespace prefix = "o" ns = "urn:schemas-microsoft-com:office:office" /-->Abstract: Inthis paper, two hybrid concatenated super-orthogonal space-time trellis codes(SOSTTC) applying iterative decoding are proposed for flat fading channels. Theencoding operation is based on the concatenation of convolutional codes,interleaving and super-orthogonal space-time trellis codes. The firstconcatenated scheme consists of a serial concatenation of a parallelconcatenated convolutional code with a SOSTTC while the second consists ofparallel concatenation of two serially concatenated convolutional and SOSTTCcodes. The decoding of these two schemes is described, their pairwise errorprobabilities are derived and the frame error rate (FER) performances areevaluated by computer simulation in Rayleigh fading channels. The proposedtopologies are shown to perform better than existing concatenated schemes with aconstituent code of convolutional andspace-time codes in literature.
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