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A comprehensive statistical model is described for ultrawideband (UWB) propagation channels that is valid for a frequency range from 3-10 GHz. It is based on measurements and simulations in the following environments: residential indoor, office indoor, builtup outdoor, industrial indoor, farm environments, and body area networks. The model is independent of(More)
We present a statistical model for the characterization of ultra-wideband (UWB) channels for the outdoor office environment. The bandwidth is from 3-6 GHz and measurements are done for the line-of-sight (LOS) and non-line-of-sight (NLOS) cases. Small scale effects are modeled by the Saleh-Valenzuela (S-V) model with modifications on the ray arrival times(More)
—Ultrawideband (UWB) technology is characterized by transmitting extremely short duration radio impulses. To improve its multiple-access capability, the UWB technology can be combined with traditional spread-spectrum techniques. This paper demonstrates the influence of spatial and temporal diversities on the performance of direct-sequence (DS) UWB(More)
—In this letter, the influence of temporal and spatial diversities on the performance of ultra-wideband time-hopping pulse-position modulated multiple-access impulse radio (IR) systems is analyzed. We investigate how an antenna array can be used at the receiver to improve the bit-error rate (BER) performance and can cope with the effects of multiple-access(More)
Handwritten character recognition is always a frontier area of research in the field of pattern recognition and image processing and there is a large demand for OCR on hand written documents. Even though, sufficient studies have performed in foreign scripts like Chinese, Japanese and Arabic characters, only a very few work can be traced for handwritten(More)
Learning disability (LD) is a neurological condition that affects a child’s brain and impairs his ability to carry out one or many specific tasks. LD affects about 10% of children enrolled in schools. There is no cure for learning disabilities and they are lifelong. The problems of children with specific learning disabilities have been a cause of concern to(More)