866 research outputs found
Improved Spatial Modulation for High Spectral Efficiency
Spatial Modulation (SM) is a technique that can enhance the capacity of MIMO
schemes by exploiting the index of transmit antenna to convey information bits.
In this paper, we describe this technique, and present a new MIMO transmission
scheme that combines SM and spatial multiplexing. In the basic form of SM, only
one out of MT available antennas is selected for transmission in any given
symbol interval. We propose to use more than one antenna to transmit several
symbols simultaneously. This would increase the spectral efficiency. At the
receiver, an optimal detector is employed to jointly estimate the transmitted
symbols as well as the index of the active transmit antennas. In this paper we
evaluate the performance of this scheme in an uncorrelated Rayleigh fading
channel. The simulations results show that the proposed scheme outperforms the
optimal SM and V-BLAST (Vertical Bell Laboratories Layered space-time at high
signal-to-noise ratio (SNR). For example, if we seek a spectral efficiency of 8
bits/s/Hz at bit error rate (BER) of 10^-5, the proposed scheme provides 5dB
and 7dB improvements over SM and V-BLAST, respectively.Comment: 7 pages, 4 figures, 1 table, International Journal of Distributed and
Parallel Systems (IJDPS) Vol.3, No.2, March 201
Design guidelines for spatial modulation
A new class of low-complexity, yet energyefficient Multiple-Input Multiple-Output (MIMO) transmission techniques, namely the family of Spatial Modulation (SM) aided MIMOs (SM-MIMO) has emerged. These systems are capable of exploiting the spatial dimensions (i.e. the antenna indices) as an additional dimension invoked for transmitting information, apart from the traditional Amplitude and Phase Modulation (APM). SM is capable of efficiently operating in diverse MIMO configurations in the context of future communication systems. It constitutes a promising transmission candidate for large-scale MIMO design and for the indoor optical wireless communication whilst relying on a single-Radio Frequency (RF) chain. Moreover, SM may also be viewed as an entirely new hybrid modulation scheme, which is still in its infancy. This paper aims for providing a general survey of the SM design framework as well as of its intrinsic limits. In particular, we focus our attention on the associated transceiver design, on spatial constellation optimization, on link adaptation techniques, on distributed/ cooperative protocol design issues, and on their meritorious variants
Receive Spatial Modulation for Massive MIMO Systems
In this paper, we consider the downlink of a massive
multiple-input-multiple-output (MIMO) single user transmission system operating
in the millimeter wave outdoor narrowband channel environment. We propose a
novel receive spatial modulation architecture aimed to reduce the power
consumption at the user terminal, while attaining a significant throughput. The
energy consumption reduction is obtained through the use of analog devices
(amplitude detector), which reduces the number of radio frequency chains and
analog-to-digital-converters (ADCs). The base station transmits spatial and
modulation symbols per channel use. We show that the optimal spatial symbol
detector is a threshold detector that can be implemented by using one bit ADC.
We derive closed form expressions for the detection threshold at different
signal-to-noise-ratio (SNR) regions showing that a simple threshold can be
obtained at high SNR and its performance approaches the exact threshold. We
derive expressions for the average bit error probability in the presence and
absence of the threshold estimation error showing that a small number of pilot
symbols is needed. A performance comparison is done between the proposed system
and fully digital MIMO showing that a suitable constellation selection can
reduce the performance gap
Energy Efficient Transmission over Space Shift Keying Modulated MIMO Channels
Energy-efficient communication using a class of spatial modulation (SM) that
encodes the source information entirely in the antenna indices is considered in
this paper. The energy-efficient modulation design is formulated as a convex
optimization problem, where minimum achievable average symbol power consumption
is derived with rate, performance, and hardware constraints. The theoretical
result bounds any modulation scheme of this class, and encompasses the existing
space shift keying (SSK), generalized SSK (GSSK), and Hamming code-aided SSK
(HSSK) schemes as special cases. The theoretical optimum is achieved by the
proposed practical energy-efficient HSSK (EE-HSSK) scheme that incorporates a
novel use of the Hamming code and Huffman code techniques in the alphabet and
bit-mapping designs. Experimental studies demonstrate that EE-HSSK
significantly outperforms existing schemes in achieving near-optimal energy
efficiency. An analytical exposition of key properties of the existing GSSK
(including SSK) modulation that motivates a fundamental consideration for the
proposed energy-efficient modulation design is also provided
Multidimensional Index Modulation in Wireless Communications
In index modulation schemes, information bits are conveyed through indexing
of transmission entities such as antennas, subcarriers, times slots, precoders,
subarrays, and radio frequency (RF) mirrors. Index modulation schemes are
attractive for their advantages such as good performance, high rates, and
hardware simplicity. This paper focuses on index modulation schemes in which
multiple transmission entities, namely, {\em antennas}, {\em time slots}, and
{\em RF mirrors}, are indexed {\em simultaneously}. Recognizing that such
multidimensional index modulation schemes encourage sparsity in their transmit
signal vectors, we propose efficient signal detection schemes that use
compressive sensing based reconstruction algorithms. Results show that, for a
given rate, improved performance is achieved when the number of indexed
transmission entities is increased. We also explore indexing opportunities in
{\em load modulation}, which is a modulation scheme that offers power
efficiency and reduced RF hardware complexity advantages in multiantenna
systems. Results show that indexing space and time in load modulated
multiantenna systems can achieve improved performance
On the Capacity and Performance of Generalized Spatial Modulation
Generalized spatial modulation (GSM) uses antenna elements but fewer
radio frequency (RF) chains () at the transmitter. Spatial modulation and
spatial multiplexing are special cases of GSM with and ,
respectively. In GSM, apart from conveying information bits through
modulation symbols, information bits are also conveyed through the indices of
the active transmit antennas. In this paper, we derive lower and upper
bounds on the the capacity of a ()-GSM MIMO system, where is the
number of receive antennas. Further, we propose a computationally efficient GSM
encoding (i.e., bits-to-signal mapping) method and a message passing based
low-complexity detection algorithm suited for large-scale GSM-MIMO systems.Comment: Expanded version of the IEEE Communications Letters pape
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