Abstract: System and methods include transmitting the same signal in all sub-bands in different time intervals and processing the corresponding received signals to achieve a time resolution proportional to the inverse of the whole bandwidth as opposed to that of a single sub-band. The systems and methods refine the coarse resolution that is achieved by conventional approaches, such as the correlation method, in a single sub-band by aligning the outputs of the matched filters to the received signals from all sub-bands and applying a fast Fourier Transform (FFT) in each time bin along the sub-band index.

Abstract: Systems and methods provide for increasing time resolution in digital communication systems by properly processing several received signals transmitted in different bands or time slots. The received signals correspond to sub-signals that are obtained by performing a filter bank decomposition of a signal with high time resolution. The time resolution of the system is proportional to the inverse of the product of the number of sub-signals and their individual bandwidth. In the presence of additive white Gaussian noise, finer time resolution can be achieved by using the disclosed approach.

Abstract: High-bit rate communication system for networking computing systems are described. The system uses a hybrid ultra-wideband orthogonal frequency division-multiplexing scheme. The transmitted signals are sparse pulse trains modulated by a frequency selected from a properly designed set of frequencies. The train itself consists of frequency modulated ultra-wide pulses. Sigma-Delta modulation is used in some implementations. Additionally, pilots can be transmitted over some subcarriers to demodulate an information bearing subcarrier. The system achieves good detection by integrating several pulses, and high throughput by transmitting frequencies in parallel. Unlike traditional orthogonal frequency division-multiplexing systems, a given tone is transmitted only during parts of the transmission interval.

Abstract: High-bit rate communication system for short range networking in high performance computing clusters are described. The system uses a hybrid ultra-wideband orthogonal frequency division-multiplexing scheme. The transmitted signals are sparse pulse trains modulated by a frequency selected from a properly designed set of frequencies. The train itself consists of frequency modulated ultra-wide pulses. The system achieves good detection by integrating several pulses, and high throughput by transmitting frequencies in parallel. Unlike traditional orthogonal frequency division-multiplexing systems, a given tone is transmitted only during parts of the transmission interval.