47,390 research outputs found
Space-Time Coded Spatial Modulated Physical Layer Network Coding for Two-Way Relaying
Using the spatial modulation approach, where only one transmit antenna is
active at a time, we propose two transmission schemes for two-way relay channel
using physical layer network coding with space time coding using Coordinate
Interleaved Orthogonal Designs (CIOD's). It is shown that using two
uncorrelated transmit antennas at the nodes, but using only one RF transmit
chain and space-time coding across these antennas can give a better performance
without using any extra resources and without increasing the hardware
implementation cost and complexity. In the first transmission scheme, two
antennas are used only at the relay, Adaptive Network Coding (ANC) is employed
at the relay and the relay transmits a CIOD Space Time Block Code (STBC). This
gives a better performance compared to an existing ANC scheme for two-way relay
channel which uses one antenna each at all the three nodes. It is shown that
for this scheme at high SNR the average end-to-end symbol error probability
(SEP) is upper bounded by twice the SEP of a point-to-point fading channel. In
the second transmission scheme, two transmit antennas are used at all the three
nodes, CIOD STBC's are transmitted in multiple access and broadcast phases.
This scheme provides a diversity order of two for the average end-to-end SEP
with an increased decoding complexity of for an arbitrary
signal set and for square QAM signal set.Comment: 9 pages, 7 figure
Performance Analysis of TCM OSTBC MIMO System in Different Fading Environment
Many wireless networks are become part of our daily life. The data rate and range in wireless devices are limited. To overcome this limitation one method is used named MIMO(Multiple input multiple output) is used. Multiple Input Multiple Output (MIMO) systems are wireless systems with multiple antenna elements at both ends of the link. MIMO systems have the ability to exploit, rather than combat, multipath propagation and promise a significant increase in capacity. MIMO communications use multiple antennas at both the transmitter and receiver to exploit the spatial domain for spatial multiplexing and/or spatial diversity. In contrast to spatial multiplexing the purpose of spatial diversity is to increase the diversity order of a MIMO link to mitigate fading by coding a signal across space and time, so that a receiver could receive the replicas of the signal and combine those received signals constructively to achieve a diversity gain. For improving the diversity gain with MIMO OSTBC(Orthogonal Space Time Block Code) . This MIMO OSTBC is used with conventional modulation scheme. Then this system is used using TCM(Trellis Coded Modulation). By using TCM OSTBC MIMO diversity can be achieved higher
A virtual MIMO dual-hop architecture based on hybrid spatial modulation
International audienceIn this paper, we propose a novel Virtual Multiple-Input-Multiple-Output (VMIMO) architecture based on the concept of Spatial Modulation (SM). Using a dual-hop and Decode-and-Forward protocol, we form a distributed system, called Dual-Hop Hybrid SM (DH-HSM). DH-HSM conveys information from a Source Node (SN) to a Destination Node (DN) via multiple Relay Nodes (RNs). The spatial position of the RNs is exploited for transferring information in addition to, or even without, a conventional symbol. In order to increase the performance of our architecture, while keeping the complexity of the RNs and DN low, we employ linear precoding using Channel State Information (CSI) at the SN. In this way, we form a Receive-Spatial Modulation (R-SM) pattern from the SN to the RNs, which is able to employ a centralized coordinated or a distributed uncoordinated detection algorithm at the RNs. In addition, we focus on the SN and propose two regularized linear precoding methods that employ realistic Imperfect Channel State Information at the Transmitter. The power of each precoder is analyzed theoretically. Using the Bit Error Rate (BER) metric, we evaluate our architecture against the following benchmark systems: 1) single relay; 2) best relay selection; 3) distributed Space Time Block Coding (STBC) VMIMO scheme; and 4) the direct communication link. We show that DH-HSM is able to achieve significant Signal-to-Noise Ratio (SNR) gains, which can be as high as 10.5 dB for a very large scale system setup. In order to verify our simulation results, we provide an analytical framework for the evaluation of the Average Bit Error Probability (ABEP)
Adaptive spatial mode of space-time and spacefrequency OFDM system over fading channels
In this paper we present a 2 transmit 1 receive (1 Tx : 1 Rx) adaptive spatial
mode (ASM) of space-time (ST) and space-frequency (SF) orthogonal frequency division
multiplexing (OFDM). At low signal to noise ratio (SNR) we employ ST-OFDM and switch
to SF-OFDM at a certain SNR threshold. We determine this threshold from the intersection
of individual performance curves. Results show a gain of 9 dB (at a bit error rate of 10-3) is
achieved by employing adaptive spatial mode compared to a fixed ST-OFDM, almost 6 dB
to fixed SF-OFDM, 4 dB to Coded ST-OFDM and 2 dB to a fixed coded SF-OFDM, at a
delay spread of 700 ns
Modulation Diversity for Spatial Modulation Using Complex Interleaved Orthogonal Design
In this paper, we propose modulation diversity techniques for Spatial
Modulation (SM) system using Complex Interleaved Orthogonal Design (CIOD) meant
for two transmit antennas. Specifically, we show that by using the CIOD for two
transmit antenna system, the standard SM scheme, where only one transmit
antenna is activated in any symbol duration, can achieve a transmit diversity
order of two. We show with our simulation results that the proposed schemes
offer transmit diversity order of two, and hence, give a better Symbol Error
Rate performance than the SM scheme with transmit diversity order of one.Comment: 7 page
A universal space-time architecture for multiple-antenna aided systems
In this tutorial, we first review the family of conventional multiple-antenna techniques, and then we provide a general overview of the recent concept of the powerful Multiple-Input Multiple-Output (MIMO) family based on a universal Space-Time Shift Keying (STSK) philosophy. When appropriately configured, the proposed STSK scheme has the potential of outperforming conventional MIMO arrangements
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
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
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