4 research outputs found
The Discussion on Shannon channel capacity formula from the viewpoint of signal uncertainty and Research on the Technique of Breaking through the Shannon Limit
In this paper, firstly, the Shannon channel capacity formula is briefly
stated, and the relationship between the formula and the signal uncertainty
principle is analyzed in order to prepare for deriving the formula which is
able to break through the Shannon channel capacity. Then, as a practical
example of breaking the Shannon limit, the time-shift non orthogonal
multicarrier modulation technology is introduced. After more than twenty years
of development, this technique is proved to be a practical modulation technique
for digital communication
Energy Efficient Optimization of Wireless-powered 5G Full Duplex Cellular Networks: A Mean Field Game Approach
This paper studies the power allocation of an ultra-dense cellular network
consisting of multiple full-duplex (FD) base stations (BSs) serving a large
number of half-duplex (HD) user equipments (UEs) located in a wide geographical
area. Each BS consists of a baseband unit (BBU) that is responsible for signal
processing and base station control, and a radio remote unit (RRU) that
corresponds to a radio transceiver remotely built closer to the UEs. We
consider a wireless-powered cellular network in which the BBU can periodically
charge the RRU. We model the energy efficiency and coverage optimization
problem for this network as a mean field game. We consider the weighted energy
efficiency of the BS as the main performance metrics and evaluate the optimal
strategy that can be adopted by the FD BSs in an ultra-dense network setting.
Based on the interference and network energy efficiency models of the mean
field game theory, Nash equilibrium of our proposed game is derived. Utilizing
solutions of Hamilton-Jacobi-Bellman (HJB) and Fokker-Planck-Kolmogorov (FPK)
equations, a new power transmission strategy is developed for the BSs to
optimize the energy efficiency of 5G cellular networks with full duplex
transmissions. Simulation results indicate that the proposed strategy not only
improves the energy efficiency but also ensures the average network coverage
probability converges to a stable level
Full-Duplex Massive MIMO Multi-Pair Two-Way AF Relaying: Energy Efficiency Optimization
We consider two-way amplify and forward relaying, where multiple full-duplex
user pairs exchange information via a shared full-duplex massive multiple-input
multiple-output (MIMO) relay. Most of the previous massive MIMO relaying works
maximize the spectral efficiency (SE). By contrast, we maximize the non-convex
energy efficiency (EE) metric by approximating it as a pseudo-concave problem,
which is then solved using the classic Dinkelbach approach. We also maximize
the EE of the least energy-efficient user {relying} on the max-min approach.
For solving these optimization problems, we derive closed-form lower bounds for
the ergodic achievable rate both for maximal-ratio combining and zero-forcing
processing at the relay, by using minimum mean squared error channel
estimation. We numerically characterize the accuracy of the lower bounds
derived. We also compare the SE and EE of the proposed design to those of the
existing full-duplex systems and quantify the significant improvement achieved
by the proposed algorithm. We also compare the EE of the proposed full-duplex
system to that of its half-duplex counterparts, and characterize the self-loop
and inter-user interference regimes, for which the proposed full-duplex system
succeeds in outperforming the half-duplex ones.Comment: 30 pages, Updated pape
Performance of Network-Assisted Full-Duplex for Cell-Free Massive MIMO
Network assisted full-duplex (NAFD) is a spatial-division duplex technique
for future wireless networks with cell-free massive multiple-input
multiple-output (CF massive MIMO) network, where a large number of remote
antenna units (RAUs), either using half-duplex or full-duplex, jointly support
truly flexible duplex including time-division duplex, frequency-division duplex
and full duplex on demand of uplink and downlink traffic by using network MIMO
methods. With NAFD, bi-directional data rates of the wireless network could be
increased and end-to-end delay could be reduced. In this paper, the spectral
efficiency of NAFD communications in CF massive MIMO network with imperfect
channel state information (CSI) is investigated under spatial correlated
channels. Based on large dimensional random matrix theory, the deterministic
equivalents for the uplink sum-rate with minimum-mean-square-error (MMSE)
receiver as well as the downlink sum-rate with zero-forcing (ZF) and
regularized zero-forcing (RZF) beamforming are derived. Numerical results show
that under various environmental settings, the deterministic equivalents are
accurate in both a large-scale system and system with a finite number of
antennas. It is also shown that with the downlink-to-uplink interference
cancellation, the uplink spectral efficiency of CF massive MIMO with NAFD could
be improved. The spectral efficiencies of NAFD with different duplex
configurations such as in-band full-duplex, and half-duplex are compared. With
the same total numbers of transmit and receive antennas, NAFD with half-duplex
RAUs offers a higher spectral efficiency. To alleviate the uplink-to-downlink
interference, a novel genetic algorithm based user scheduling strategy (GAS) is
proposed. Simulation results show that the achievable downlink sum-rate by
using the GAS is greatly improved compared to that by using the random user
scheduling