Conventional amplitude-phase modulations (APMs) are designed such that the minimum Euclidean distance between constellation points is maximized. Unlike these modulations, the error performance of spatial modulation (S...
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ISBN:
(纸本)9781467364300
Conventional amplitude-phase modulations (APMs) are designed such that the minimum Euclidean distance between constellation points is maximized. Unlike these modulations, the error performance of spatial modulation (SM) is not only a function of the Euclidean distances but also the energy of each symbol, i.e. constellation point. Therefore, conventional APM schemes that are designed solely based on the notion of Euclidean distance are not necessarily suitable for SM transmission. In this paper, the constellation design for SM is investigated and it is shown that, by a proper constellation design, a significant performance gain is obtained compared to the well-known phase shift keying (PSK) or quadrature amplitude modulation (QAM). It is shown that in many cases multi-ring star-QAM is a suitable constellation for SM. However, when the number of transmit antennas is large, the numerically derived constellation converges to the conventional phase shift keying (PSK) constellation, especially at small number of receive antennas.
In mid 90(s) researches of A. PaulrajS. Kailath et al, E. Telatar and the historical research of G. FoschiniJ. Gans "On Limits of Wireless Communications in a Fading Environment when Using multiple Antennas"...
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In mid 90(s) researches of A. PaulrajS. Kailath et al, E. Telatar and the historical research of G. FoschiniJ. Gans "On Limits of Wireless Communications in a Fading Environment when Using multiple Antennas";instigated a new era in the modern wireless communication. The research of G. FoschiniJ. Gans led to what became defined as Space Time (ST) premise. Their study depicted mathematical models for optimizing spatial sharing of the physical link (channel capacity) through use of multi-element antenna MEA (space dimension). Use of space dimension opened new avenues to produce efficient coding and modulation techniques by exploring various combinations between spatial and the established timefrequency techniques. It has become a part of today's WCT necessities, that wireless designers acquire a profound understanding of this premise. This paper reviews the capacity limits in MEA channel, as expressed by G. FoschiniJ. Gans and E. Telatar and the impact of their findings on succeeding developments in WCT field. The paper includes a brief description of two selected ST schemes;multi-input-multi-output with Orthogonal-Frequency-Division-multiplexing (MIMO-OFDM) and a method to exploit the location diversity of multiple Antenna Sites (MAS) for spatial multiplexing "SFN-MAP-TDD-MIMO- OFDM technique". Finally, paper predicts and discusses the next probable development roots in WCT.
The performance of amplify-and-forward (AF) multi-input multi-output (MIMO) two way relaying networks (TWRNs) with multiple antenna selection scheme at the sources, while having single antenna selection at the relay n...
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ISBN:
(纸本)9781509032556
The performance of amplify-and-forward (AF) multi-input multi-output (MIMO) two way relaying networks (TWRNs) with multiple antenna selection scheme at the sources, while having single antenna selection at the relay node is investigated to maximize the effective signal-to-noise ratio (SNR) over flat Rayleigh fading channel. Both exact and asymptotic expressions for the sum outage probability are derived and verified through Monte Carlo simulation results. The diversity order of selection scheme is proven to be minimum of the number of antennas of the source with larger antennas and the product of the number of relay antennas with the number of antennas of the source having fewer antennas. It is shown that fewer antennas at the sources can be selected to reduce the complexity without a significant loss in performance with respect to full antenna usage, i.e., with respect to beamforming. Primary factors which affect optimum relay location are also determined.
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