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This paper provides an overview and preliminary comparison of several multi-carrier and single- carrier waveforms that are potential candidates for future 5G mobile radio communications above 6 GHz. The waveforms are assessed primarily based on the established and known results as well as recent findings keeping in view the design requirements that are relevant to using frequencies above 6 GHz, especially...
Multi-band multi-standard Base Stations (BS) are believed to be one promising solution to manage the coexistence of different technological standards (e.g. 2G/3G/4G) with reasonable installation and operation costs. Except for multi-technology baseband (BB) units and multi-band/broadband RF-frontends e.g. antenna and Power Amplifier (PA), the realization of such BSs requires sophisticated cooperation...
MIMO OFDM is a key technique for achieving high data rate in future wireless communication systems. The desired low-cost, low-power and fully integrated implementation of MIMO OFDM systems leads to the application of direct (up/down) conversion architecture, whose performance can be seriously limited by I/Q-imbalance. Thus, the compensation of I/Q-imbalance is a crucial issue in the implementation...
In this paper, four transmit beamforming (BF) techniques are selected and compared to realize inter-operator spectrum sharing, which is a promising solution for the spectrum shortage problem. The BF techniques include two game-theoretic (GT) algorithms, zero-forcing (ZF) and minimum mean square error (MMSE). After a brief description of the BF techniques in a multiple-input single-output (MISO) system,...
Satisfiability degree is used as a new means of representing uncertainty. It is able to express the extent of a system satisfying some property. How to compute the satisfiability degree is a critically problem. Although this paper has proved the computation for the satisfiability degree has the exponential worst case complexity, the proposition matrix is proposed to construct the proposition matrix...
In this paper, antenna diversity (AD) schemes are presented for frequency-domain (FD) multi-user detection (MUD) in the up-link (UL) of cellular systems which apply CP (Cyclic Prefix) assisted DS-CDMA (direct sequence code division multiple access). Alamouti-based space-time-code (STC) was applied to exploit transmitter (TX) diversity. The MUD and the diversity combining in the receiver (RX) are MMSE...
In this paper, channel estimation schemes as well as low crest-factor preamble construction are presented for practical MIMO OFDM systems with NULL subcarriers. In the presence of NULL subcarriers, the performance of the channel estimator in [1] degrades considerably. Therefore, Maximum-likelihood (ML) channel estimators were proposed for MIMO OFDM systems with NULL subcarriers [2], [3]. However,...
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