1,882 research outputs found
Full-Duplex MIMO Small-Cell Networks: Performance Analysis
Full-duplex small-cell relays with multiple antennas constitute a core
element of the envisioned 5G network architecture. In this paper, we use
stochastic geometry to analyze the performance of wireless networks with
full-duplex multiple-antenna small cells, with particular emphasis on the
probability of successful transmission. To achieve this goal, we additionally
characterize the distribution of the self-interference power of the full-duplex
nodes. The proposed framework reveals useful insights on the benefits of
full-duplex with respect to half-duplex in terms of network throughput
Energy efficiency of transmit diversity systems under a realistic power consumption model
We compare the downlink energy efficiency of spatial diversity multiple transmit antenna schemes. We determine the minimum required transmit power for a given outage probability. Our analysis shows that antenna selection is in general the most energy efficient option as it requires a single radio-frequency chain. We also investigate the limiting distances up to which the antenna selection technique outperforms the transmit beamforming scheme for different numbers of transmit antennas
Area Spectral Efficiency Analysis and Energy Consumption Minimization in Multi-Antenna Poisson Distributed Networks
This paper aims at answering two fundamental questions: how area spectral
efficiency (ASE) behaves with different system parameters; how to design an
energy-efficient network. Based on stochastic geometry, we obtain the
expression and a tight lower-bound for ASE of Poisson distributed networks
considering multi-user MIMO (MU-MIMO) transmission. With the help of the
lower-bound, some interesting results are observed. These results are validated
via numerical results for the original expression. We find that ASE can be
viewed as a concave function with respect to the number of antennas and active
users. For the purpose of maximizing ASE, we demonstrate that the optimal
number of active users is a fixed portion of the number of antennas. With
optimal number of active users, we observe that ASE increases linearly with the
number of antennas. Another work of this paper is joint optimization of the
base station (BS) density, the number of antennas and active users to minimize
the network energy consumption. It is discovered that the optimal combination
of the number of antennas and active users is the solution that maximizes the
energy-efficiency. Besides the optimal algorithm, we propose a suboptimal
algorithm to reduce the computational complexity, which can achieve near
optimal performance.Comment: Submitted to IEEE Transactions on Wireless Communications, Major
Revisio
Joint Source and Relay Precoding Designs for MIMO Two-Way Relaying Based on MSE Criterion
Properly designed precoders can significantly improve the spectral efficiency
of multiple-input multiple-output (MIMO) relay systems. In this paper, we
investigate joint source and relay precoding design based on the
mean-square-error (MSE) criterion in MIMO two-way relay systems, where two
multi-antenna source nodes exchange information via a multi-antenna
amplify-and-forward relay node. This problem is non-convex and its optimal
solution remains unsolved. Aiming to find an efficient way to solve the
problem, we first decouple the primal problem into three tractable
sub-problems, and then propose an iterative precoding design algorithm based on
alternating optimization. The solution to each sub-problem is optimal and
unique, thus the convergence of the iterative algorithm is guaranteed.
Secondly, we propose a structured precoding design to lower the computational
complexity. The proposed precoding structure is able to parallelize the
channels in the multiple access (MAC) phase and broadcast (BC) phase. It thus
reduces the precoding design to a simple power allocation problem. Lastly, for
the special case where only a single data stream is transmitted from each
source node, we present a source-antenna-selection (SAS) based precoding design
algorithm. This algorithm selects only one antenna for transmission from each
source and thus requires lower signalling overhead. Comprehensive simulation is
conducted to evaluate the effectiveness of all the proposed precoding designs.Comment: 32 pages, 10 figure
Performance Analysis of Dual-User Macrodiversity MIMO Systems with Linear Receivers in Flat Rayleigh Fading
The performance of linear receivers in the presence of co-channel
interference in Rayleigh channels is a fundamental problem in wireless
communications. Performance evaluation for these systems is well-known for
receive arrays where the antennas are close enough to experience equal average
SNRs from a source. In contrast, almost no analytical results are available for
macrodiversity systems where both the sources and receive antennas are widely
separated. Here, receive antennas experience unequal average SNRs from a source
and a single receive antenna receives a different average SNR from each source.
Although this is an extremely difficult problem, progress is possible for the
two-user scenario. In this paper, we derive closed form results for the
probability density function (pdf) and cumulative distribution function (cdf)
of the output signal to interference plus noise ratio (SINR) and signal to
noise ratio (SNR) of minimum mean squared error (MMSE) and zero forcing (ZF)
receivers in independent Rayleigh channels with arbitrary numbers of receive
antennas. The results are verified by Monte Carlo simulations and high SNR
approximations are also derived. The results enable further system analysis
such as the evaluation of outage probability, bit error rate (BER) and
capacity.Comment: 24 pages, 7 figures; IEEE Transaction of Wireless Communication 2012
Corrected typo
Maximum likelihood detection for differential unitary space-time modulation with carrier frequency offset
Can conventional differential unitary space time modulation (DUSTM) be applied when there is an unknown carrier frequency offset (CFO)? This paper answers this question affirmatively and derives the necessary maximum likelihood (ML) detection rule. The asymptotic performance of the proposed ML rule is analyzed, leading to a code design criterion for DUSTM by using the modified diversity product. The resulting proposed decision rule is a new differential modulation scheme in both the temporal and spatial domains. Two sub-optimal multiple-symbol decision rules with improved performance are also proposed. For the efficient implementation of these, we derive a modified bound intersection detector (BID), a generalization of the previously derived optimal BID for the conventional DUSTM. The simulation results show that the proposed differential modulation scheme is more robust against CFO drifting than the existing double temporal differential modulation
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