141 research outputs found
Maximal Ratio Transmission in Wireless Poisson Networks under Spatially Correlated Fading Channels
The downlink of a wireless network where multi-antenna base stations (BSs)
communicate with single-antenna mobile stations (MSs) using maximal ratio
transmission (MRT) is considered here. The locations of BSs are modeled by a
homogeneous Poisson point process (PPP) and the channel gains between the
multiple antennas of each BS and the single antenna of each MS are modeled as
spatially arbitrarily correlated Rayleigh random variables. We first present
novel closed-form expressions for the distribution of the power of the
interference resulting from the coexistence of one intended and one unintended
MRT over the considered correlated fading channels. The derived expressions are
then used to obtain closed-form expressions for the success probability and
area spectral efficiency of the wireless communication network under
investigation. Simulation results corroborate the validity of the presented
expressions. A key result of this work is that the effect of spatial
correlation on the network throughput may be contrasting depending on the
density of BSs, the signal-to-interference-plus-noise ratio (SINR) level, and
the background noise power.Comment: 6 pages, 6 figures, IEEE GLOBECOM 201
Jointly Optimal Spatial Channel Assignment and Power Allocation for MIMO SWIPT Systems
The joint design of spatial channel assignment and power allocation in
Multiple Input Multiple Output (MIMO) systems capable of Simultaneous Wireless
Information and Power Transfer (SWIPT) is studied. Assuming availability of
channel state information at both communications ends, we maximize the
harvested energy at the multi-antenna receiver, while satisfying a minimum
information rate requirement for the MIMO link. We first derive the globally
optimal eigenchannel assignment and power allocation design, and then present a
practically motivated tight closed-form approximation for the optimal design
parameters. Selected numerical results verify the validity of the optimal
solution and provide useful insights on the proposed designs as well as the
pareto-optimal rate-energy tradeoff.Comment: 5 pages; 4 figures; accepted to IEEE journal 201
Joint Design of Multi-Tap Analog Cancellation and Digital Beamforming for Reduced Complexity Full Duplex MIMO Systems
Incorporating full duplex operation in Multiple Input Multiple Output (MIMO)
systems provides the potential of boosting throughput performance. However, the
hardware complexity of the analog self-interference canceller scales with the
number of transmit and receive antennas, thus exploiting the benefits of analog
cancellation becomes impractical for full duplex MIMO transceivers. In this
paper, we present a novel architecture for the analog canceller comprising of
reduced number of taps (tap refers to a line of fixed delay and variable phase
shifter and attenuator) and simple multiplexers for efficient signal routing
among the transmit and receive radio frequency chains. In contrast to the
available analog cancellation architectures, the values for each tap and the
configuration of the multiplexers are jointly designed with the digital
beamforming filters according to certain performance objectives. Focusing on a
narrowband flat fading channel model as an example, we present a general
optimization framework for the joint design of analog cancellation and digital
beamforming. We also detail a particular optimization objective together with
its derived solution for the latter architectural components. Representative
computer simulation results demonstrate the superiority of the proposed low
complexity full duplex MIMO system over lately available ones.Comment: 8 pages, 4 figures, IEEE ICC 201
A Comparative Study of Relaying Schemes with Decode-and-Forward over Nakagami-m Fading Channels
Utilizing relaying techniques to improve performance of wireless systems is a
promising avenue. However, it is crucial to understand what type of relaying
schemes should be used for achieving different performance objectives under
realistic fading conditions. In this paper, we present a general framework for
modelling and evaluating the performance of relaying schemes based on the
decode-and-forward (DF) protocol over independent and not necessarily
identically distributed (INID) Nakagami-m fading channels. In particular, we
present closed-form expressions for the statistics of the instantaneous output
signal-to-noise ratio of four significant relaying schemes with DF; two based
on repetitive transmission and the other two based on relay selection (RS).
These expressions are then used to obtain closed-form expressions for the
outage probability and the average symbol error probability for several
modulations of all considered relaying schemes over INID Nakagami-m fading.
Importantly, it is shown that when the channel state information for RS is
perfect, RS-based transmission schemes always outperform repetitive ones.
Furthermore, when the direct link between the source and the destination nodes
is sufficiently strong, relaying may not result in any gains and in this case
it should be switched-off.Comment: Submitted to Journal of Computer Systems, Networks, and
Communication
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