Ultra-wideband for multiple access communications

Ultra-wideband wireless communications techniques have many merits, including an extremely simple radio that inherently leads to low-cost design, large processing gain for robust operations in the presence of narrowband interference, covert operations, and fine time resolution for accurate position sensing. However, there are a number of challenges in UWB receiver design, such as capturing multipath energy, intersymbol interference especially in a non-line-of-sight environment, and the need for high-sampling-rate analog-to-digital converters. In this article we provide a comprehensive review of UWB multiple access and modulation schemes, and their comparison with narrowband radios. We also outline issues with UWB signal reception and detection, and explore various suboptimal low-complexity receiving schemes.