In this paper, we propose a novel communication strategy which incorporates
physical-layer network coding (PNC) into multiple-input multiple output (MIMO)
two-way relay channels (TWRCs). At the heart of the proposed scheme lies a new
key technique referred to as eigen-direction alignment (EDA) precoding. The EDA
precoding efficiently aligns the two-user's eigen-modes into the same
directions. Based on that, we carry out multi-stream PNC over the aligned
eigen-modes. We derive an achievable rate of the proposed EDA-PNC scheme, based
on nested lattice codes, over a MIMO TWRC.

Spectrum sensing is mandatory in Cognitive Radio systems, and is used in
order to identify spectrum opportunities, and to guarantee that it does not
cause unacceptable interference to the license owner. Since a single sensor may
be in fading or shadowing, cooperative sensing among multiple sensors which
experience uncorrelated fading is required to guarantee reliable sensing
performance. In this paper we develop efficient centralized statistical
algorithms for cooperative spectrum sensing in a cooperative based cognitive
radio network.

This paper presents a new approach for channel tracking and parameter
estimation in cooperative wireless relay networks. We consider a system with
multiple relay nodes operating under an amplify and forward relay function. We
develop a novel algorithm to efficiently solve the challenging problem of joint
channel tracking and parameters estimation of the Jakes' system model within a
mobile wireless relay network. This is based on a novel particle Markov chain
Monte Carlo (PMCMC) method.

This paper deals with the challenging problem of spectrum sensing in
cognitive radio. We consider a stochastic system model where the the Primary
User (PU) transmits a periodic signal over fading channels. The effect of
frequency offsets due to oscillator mismatch, and Doppler offset is studied. We
show that for this case the Likelihood Ratio Test (LRT) cannot be evaluated
poitnwise. We present a novel approach to approximate the marginilisation of
the frequency offset using a single point estimate.

In this paper we investigate a multi-source LDPC scheme for a Gaussian relay
system, where M sources communicate with the destination under the help of a
single relay (M-1-1 system). Since various distributed LDPC schemes in the
cooperative single-source system, e.g. bilayer LDPC and bilayer multi-edge type
LDPC (BMET-LDPC), have been designed to approach the Shannon limit, these
schemes can be applied to the $M-1-1$ system by the relay serving each source
in a round-robin fashion. However, such a direct application is not optimal due
to the lack of potential joint processing gain.