1,780 research outputs found
Single-Carrier Modulation versus OFDM for Millimeter-Wave Wireless MIMO
This paper presents results on the achievable spectral efficiency and on the
energy efficiency for a wireless multiple-input-multiple-output (MIMO) link
operating at millimeter wave frequencies (mmWave) in a typical 5G scenario. Two
different single-carrier modem schemes are considered, i.e., a traditional
modulation scheme with linear equalization at the receiver, and a
single-carrier modulation with cyclic prefix, frequency-domain equalization and
FFT-based processing at the receiver; these two schemes are compared with a
conventional MIMO-OFDM transceiver structure. Our analysis jointly takes into
account the peculiar characteristics of MIMO channels at mmWave frequencies,
the use of hybrid (analog-digital) pre-coding and post-coding beamformers, the
finite cardinality of the modulation structure, and the non-linear behavior of
the transmitter power amplifiers. Our results show that the best performance is
achieved by single-carrier modulation with time-domain equalization, which
exhibits the smallest loss due to the non-linear distortion, and whose
performance can be further improved by using advanced equalization schemes.
Results also confirm that performance gets severely degraded when the link
length exceeds 90-100 meters and the transmit power falls below 0 dBW.Comment: accepted for publication on IEEE Transactions on Communication
MIMO Transceiver Optimization With Linear Constraints on Transmitted Signal Covariance Components
This correspondence revisits the joint transceiver optimization problem for multiple-input multiple-output (MIMO) channels. The linear transceiver as well as the transceiver with linear precoding and decision feedback equalization are considered. For both types of transceivers, in addition to the usual total power constraint, an individual power constraint on each antenna element is also imposed. A number of objective functions including the average bit error rate, are considered for both of the above systems under the generalized power constraint. It is shown that for both types of systems the optimization problem can be solved by first solving a class of MMSE problems (AM-MMSE or GM-MMSE depending on the type of transceiver), and then using majorization theory. The first step, under the generalized power constraint, can be formulated as a semidefinite program (SDP) for both types of transceivers, and can be solved efficiently by convex optimization tools. The second step is addressed by using results from majorization theory. The framework developed here is general enough to add any finite number of linear constraints to the covariance matrix of the input
Design of Block Transceivers with Decision Feedback Detection
This paper presents a method for jointly designing the transmitter-receiver
pair in a block-by-block communication system that employs (intra-block)
decision feedback detection. We provide closed-form expressions for
transmitter-receiver pairs that simultaneously minimize the arithmetic mean
squared error (MSE) at the decision point (assuming perfect feedback), the
geometric MSE, and the bit error rate of a uniformly bit-loaded system at
moderate-to-high signal-to-noise ratios. Separate expressions apply for the
``zero-forcing'' and ``minimum MSE'' (MMSE) decision feedback structures. In
the MMSE case, the proposed design also maximizes the Gaussian mutual
information and suggests that one can approach the capacity of the block
transmission system using (independent instances of) the same (Gaussian) code
for each element of the block. Our simulation studies indicate that the
proposed transceivers perform significantly better than standard transceivers,
and that they retain their performance advantages in the presence of error
propagation.Comment: 14 pages, 8 figures, to appear in the IEEE Transactions on Signal
Processin
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