Impulse-radio ultra-wide-band (IR-UWB) signaling is a promising technique
for high-speed, short-range relay communications networks. Depending on how
the relay node retransmits the signal, there are two main relay schemes: conventional
one-directional (one-way) relay model, and bi-directional (two-way) relay
model. In bi-directional relay communications, wireless network coding (WNC),
also called physical-layer network coding (PNC), could be applied to overcome
the spectral efficiency limitation of the conventional one-way relay.
In the first part of this work, we propose asynchronous, differential, and
bidirectional decode and forward (ADBDF) and asynchronous, differential, and
bidirectional denoise and forward (ADBDNF) UWB relay methods, where the
relay node (RN) does not need to be synchronized with the end nodes (ENs). The
proposed schemes are attractive for networks in which stringent/complicated
synchronization between the RN and the ENs may not be feasible.
The second part of this work focuses on UWB channel classification. We propose
a 2-dimensional (2-D) LOS/NLOS classification scheme that uses skewness of the channel impulse/pulse response. The proposed channel classification decreases
the complexity of existing channel classification methods and can be used
in a variety of areas such as localization, relay communications, and cooperative
communications.
The final part of this work deals with compressive sensing (CS) algorithms
that employ sub-Nyquist sampling for UWB communications. We develop coarse
graining (CG) for the proposed CS sub-Nyquist sampling technique, which leads
to: (1) reduced sampling rate at the receiver, and hence reduced use of analog-to-digital
converters (ADCs) resources; and (2) low-complexity channel estimation
