MIMO Scheme Research Articles

An Improved MIMO Scheme for Coordinated Multi-Point Transmission System

An Improved MIMO Scheme for Coordinated Multi-Point Transmission System

Application of MAP decoding for chaos MIMO scheme to improve error rate performance

Application of MAP decoding for chaos MIMO scheme to improve error rate performance

Performance improvement of chaos MIMO scheme using advanced stochastic characteristics

Performance improvement of chaos MIMO scheme using advanced stochastic characteristics

Performance of heterogeneous multiuser MIMO system with cross-layer design over spatially correlated Rayleigh channel

Abstract By combing adaptive modulation (AM) and automatic repeat request (ARQ) protocol as well as user scheduling, cross-layer design (CLD) scheme for heterogeneous multiuser MIMO (MU-MIMO) system is presented in this paper, which takes the spatial correlation and heterogeneous users with independent non-identically distributed SNRs in practice into account. The performance of CLD scheme is investigated over spatially correlated Rayleigh channel. Based on the performance analysis and mathematical operation, using the normalized-SNR based scheduling scheme, the average spectral efficiency (SE) and packet error rate (PER) of MU-MIMO system are derived, and resulting accurate closed-form expressions are obtained. In order to simplify the performance analysis from accurate expressions, the simplified average SE and PER are further derived for weak correlation, which have simpler form than the accurate ones. Simulation results show that the derived accurate SE and PERs are in good agreement with the corresponding simulations, and the simplified expressions have the values close to the accurate ones, especially for weak correlation. Thus, the CLD performance of MU-MIMO in spatially correlated channel can be evaluated effectively.

UHDTV 방송을 위한 공간 변조 다중 안테나 시스템 수신 성능 분석

In this paper, the reception performance of spatial modulation multiple-output multiple-input (MIMO) is analyzed for high speed terrestrial broadcasting. The MIMO scheme is required to reduce the inter symbol interference (ISI) and spatial correlation. The spatial modulation scheme solves the problem of ISI, but the spatial correlation degrades the reception performance of SM scheme. The space-time block coded spatial modulation (STBC-SM) is combined the SM system with space-time block code (STBC) for reducing the effects of the spatial correlation. However, the STBC-SM scheme degrades the spectral efficiency by transmitting same data in the two symbol period. The double space-time transmit diversity with spatial modulation (DSTTD-SM) scheme transmits the data with full antenna combination. To adapt these SM MIMO systems into the terrestrial broadcasting system, the reception performance is analyzed using computer simulation in SUI channel environments.

MmWave massive-MIMO-based wireless backhaul for the 5G ultra-dense network

Ultra-dense network (UDN) has been considered as a promising candidate for future 5G network to meet the explosive data demand. To realize UDN, a reliable, Gigahertz bandwidth, and cost-effective backhaul connecting ultra-dense small-cell base stations (BSs) and macro-cell BS is prerequisite. Millimeter-wave (mmWave) can provide the potential Gbps traffic for wireless backhaul. Moreover, mmWave can be easily integrated with massive MIMO for the improved link reliability. In this article, we discuss the feasibility of mmWave massive MIMO based wireless backhaul for 5G UDN, and the benefits and challenges are also addressed. Especially, we propose a digitally-controlled phase-shifter network (DPSN) based hybrid precoding/combining scheme for mmWave massive MIMO, whereby the low-rank property of mmWave massive MIMO channel matrix is leveraged to reduce the required cost and complexity of transceiver with a negligible performance loss. One key feature of the proposed scheme is that the macro-cell BS can simultaneously support multiple small-cell BSs with multiple streams for each smallcell BS, which is essentially different from conventional hybrid precoding/combining schemes typically limited to single-user MIMO with multiple streams or multi-user MIMO with single stream for each user. Based on the proposed scheme, we further explore the fundamental issues of developing mmWave massive MIMO for wireless backhaul, and the associated challenges, insight, and prospect to enable the mmWave massive MIMO based wireless backhaul for 5G UDN are discussed.

Raptor-Coded Noncoherent Cooperative Schemes Based on Distributed Unitary Space–Time Modulation

In this paper, we investigate Raptor-coded distributed unitary space–time modulation (USTM) schemes, where both the amplify-and-forward (AF) and decode-and-forward (DF) relaying scenarios are considered, under a wireless relay network with arbitrary path gains for the channel fading coefficients. First, the AF and DF relaying procedures are investigated based on the use of an inner USTM signal and an outer Raptor code, and the related noncoherent detectors are also derived. The constellation search for the USTM signal, as well as the optimization for the Raptor code, is then investigated in order to enhance the system performance. It is shown that the designed systems effectively approach the predicted limit in throughput performances and outperform the noncoherent distributed MIMO scheme reported in the previous literature.

Adaptive Uniform Channel Decomposition in MU-MIMO-OFDM: Application to IEEE 802.11ac

This work considers the design of multiuser MIMO (MU-MIMO) schemes suitable for orthogonal frequency division multiplex (OFDM) systems such as those being currently discussed within IEEE 802.11ac. A general framework is proposed showing that the singular value decomposition (SVD), the geometric mean decomposition (GMD), and the uniform channel decomposition (UCD) are all viable mechanisms on which to lay the design. Nonetheless, some striking differences in terms of performance among these three schemes are uncovered. In particular, a novel adaptive transmission scheme based on the UCD is introduced that enables multiuser MIMO-OFDM gains to be realized, clearly outperforming those obtained using the SVD or GMD counterparts while remaining fully compliant with the latest IEEE 802.11ac specification. Relying on the UCD properties, the proposed technique takes into account the availability of a finite modulation and coding set and restrictions on transmission mode selection defined within the standard, to incorporate an optimisation step in charge of selecting the number of transmitted data streams to each user to maximise the system throughput. Comprehensive simulation results in the context of IEEE 802.11ac confirm the applicability and advantage of the adaptive UCD-based design.

Energy Efficiency of Space and Polarization MIMO Communications With Packet Erasures Over Wireless Fading Channels

The transmit energy efficiency (EE) of space- polarization multiple-input multiple-output (SpPol-MIMO) architectures, dual-polarized MIMO architectures (DP-MIMO), and conventional co-polarized MIMO (CP-MIMO) schemes are compared for packet-based communication systems using full multiplexing without channel state information at the transmitter. We develop a closed-form approximation for assessing the EE of single-input single-output (SISO) and MIMO systems and show tradeoffs that exist between EE, spectral efficiency, modulation schemes, and packet designs. Using a hardware/software testbed, we also compare the EE among SISO, 2 × 2 CP-MIMO, 2 × 2 DP-MIMO, and 4 × 4 SpPol-MIMO architectures in frequency-selective MIMO channels. Emulation results from the testbed indicate that in the high SNR-regime, SpPol-MIMO provides the best EE performance in spatially uncorrelated channels, with EEs approximately four and two times better than SISO and 2 × 2 MIMO architectures, respectively. In Rician channels exhibiting either partial or high sAbstract-The transmit energy efficiency (EE) of space- polarization multiple-input multiple-output (SpPol-MIMO) architectures, dual-polarized MIMO architectures (DP-MIMO), and conventional co-polarized MIMO (CP-MIMO) schemes are compared for packet-based communication systems using full multiplexing without channel state information at the transmitter. We develop a closed-form approximation for assessing the EE of single-input single-output (SISO) and MIMO systems and show tradeoffs that exist between EE, spectral efficiency, modulation schemes, and packet designs. Using a hardware/software testbed, we also compare the EE among SISO, 2 × 2 CP-MIMO, 2 × 2 DP-MIMO, and 4 × 4 SpPol-MIMO architectures in frequency-selective MIMO channels. Emulation results from the testbed indicate that in the high SNR-regime, SpPol-MIMO provides the best EE performance in spatially uncorrelated channels, with EEs approximately four and two times better than SISO and 2 × 2 MIMO architectures, respectively. In Rician channels exhibiting either partial or high spatial correlation, DP-MIMO offers more than a 2× performance improvement relative to the other architectures at high SNR. At low SNR, SISO systems offer the best energy efficiency but also exhibit the lowest data rates. For all of the architectures, operating points are identified that provide near achievable data rates while operating at a local minimum in energy consumption.patial correlation, DP-MIMO offers more than a 2× performance improvement relative to the other architectures at high SNR. At low SNR, SISO systems offer the best energy efficiency but also exhibit the lowest data rates. For all of the architectures, operating points are identified that provide near achievable data rates while operating at a local minimum in energy consumption.

MIMO-MMSE Model using Multiple Active Antennas for Rayleigh Fading Channel

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. This paper describes a MIMO transmission scheme that combines SM and spatial multiplexing. In the basic form of SM, only one out of NT available antennas is selected for transmission in any given symbol interval. This paper proposes to use more than one active antenna to transmit several symbols simultaneously. This would increase the spectral efficiency and decreases BER (bit error rate) at the receiver, an MMSE detector is employed to jointly estimate the Transmitted symbols as well as the index of the active transmit antennas. The results show that the detection based on zero forcing is good for noise free channel and is successful in removing ISI, but MMSE is a better choice than ZF in terms of BER characteristics and under Noise performance. In MIMO transmission scheme the uncorrelated fading channel also called statistical model is used for the effect of a propagation environment on a radio signal. Sometimes use of multiple antenna techniques is problem depended but it used because it gives better performance like heavily built urban environment where radio signals are fade and scattered.

Joint Spatial Division and Multiplexing: Opportunistic Beamforming, User Grouping and Simplified Downlink Scheduling

Joint Spatial Division and Multiplexing (JSDM) is a downlink multiuser MIMO scheme recently proposed by the authors in order to enable “massive MIMO” gains and simplified system operations for Frequency Division Duplexing (FDD) systems. The key idea lies in partitioning the users into groups with approximately similar channel covariance eigenvectors and serving these groups by using two-stage downlink precoding scheme obtained as the concatenation of a pre-beamforming matrix, that depends only on the channel second-order statistics, with a multiuser MIMO linear precoding matrix, which is a function of the effective channels including pre-beamforming. The role of pre-beamforming is to reduce the dimensionality of the effective channel by exploiting the near-orthogonality of the eigenspaces of the channel covariances of the different user groups. This paper is an extension of our initial work on JSDM, and addresses some important practical issues. First, we focus on the regime of finite number of antennas and large number of users and show that JSDM with simple opportunistic user selection is able to achieve the same scaling law of the system capacity with full channel state information. Next, we consider the large-system regime (both antennas and users growing large) and propose a simple scheme for user grouping in a realistic setting where users have different angles of arrival and angular spreads. Finally, we propose a low-overhead probabilistic scheduling algorithm that selects the users at random with probabilities derived from large-system random matrix analysis. Since only the pre-selected users are required to feedback their channel state information, the proposed scheme realizes important savings in the CSIT feedback.

Performance Analysis of Modified STBC Scheme for Cooperative MIMO Communications

The cooperative MIMO communications is a new challenge to provide more reliable transmissions from the collaboration between users. Mostly, the MIMO employment is performed by using a simple diversity scheme. However, there are many MIMO schemes that can be implemented in practice. This paper proposes the modified STBC scheme for cooperative MIMO communications. Also the performance analysis of the proposed system in term of the data error rate and the outage probability is originally presented. The simulation results indicate that the proposed system can offer a better bit error rate and improve the outage probability than the diversity scheme.

Improved Generalized Space-Shift Keying via Power Allocation

We investigate the power allocation in generalized space-shift keying (GSSK) multiple-input-multiple-output (MIMO) systems. The maximum-likelihood detection with full channel state information (CSI) at the receiver is considered. The goal of the design is to allocate transmit power on GSSK antennas to minimize the symbol error rate (SER) under the total power constraint. An upper bound of SER conditioned on CSI is presented. We propose an algorithm, called the Euclidean distance-based power allocation scheme, to minimize the SER upper bound. Simulation results demonstrate the performance superiority in the proposed scheme compared with prior space-shift-keying-type schemes and the conventional MIMO schemes.

A tensor structure proposal for the MIMO schemes implementation

This work proposes the use of tensor structures as amethod of Multiple-input Multiple-output [MIMO]schemes implementation, with the target to extend thefreedom grades that the matrix array provides, this takeimportance when include more variables of the systemfor transmit or receive information a major flexibility isachieved, but with a cost of computational complexity. Itwas verified that the use of tensor structures in the MIMOschemes allows to obtain the same results of the bit errorrate and give the possibility of increase the freedom gradesin the transmit structure.

Data Aggregation based Cooperative MIMO System for Wireless Sensor Networks: Performance Analysis

increase the life span of wireless sensor network, energy consumption must be minimized while satisfying given throughput and delay requirement. In this paper, we described an energy model based on cooperative MIMO scheme considering of both transmission and data aggregation energy is proposed for wireless sensor network. Based on this consequence, jointly considering both cooperative MIMO and data aggregation techniques which shows performance enhancement over conventional SISO system for same signal- to-noise ratio. Moreover, at critical distance value MIMO system outperforms SISO system is compared. The results show that MQAM is the best modulation technique is proved by simulations and suitable diversity technique for energy miniaturization to send a given number of bits are analyzed. Keywordsdiversity schemes, Data aggregation, Energy Efficiency, Wireless sensor network.

Alamouti Coded Blind Interference Alignment with Partial Interference Cancellation Group Decoding

Interference alignment is a promising technique which suppresses interference in multiuser wireless networks. Most research on interference alignment aims at deriving or realizing the maximum achievable Degrees of Freedom (DoF), as well as the diversity gain is usually one. However, achieving better diversity performance is equally important. To improve the diversity gain, this paper presents an Alamouti coded Blind Interference Alignment (BIA) scheme, which combines interference alignment with Alamouti coding. First, the Alamouti coded BIA scheme for a two-user MIMO X channel is proposed. The proposed scheme results in 4/3 DoF with no channel state information at transmitters, and an equivalent channel matrix with partly orthogonal columns. The orthogonal structure can be exploited to obtain diversity gain. Therefore, we then explore the Partial Interference Cancellation (PIC) group decoding and ZF algorithm. Simulation results show that the proposed scheme achieves a higher diversity gain of 2, while keeps the same DoF as the original BIA scheme.

Design a Trellis-Based Receiver to Combat CCI in EDGE Network

Like in GSM network the co-channel interference (CCI) is popular in EDGE network due to the problem of reusing frequency in distant cells. Although the distance between cells using the same frequencies is quite far but CCI still causes significant effect to the channel capacity rather than noise. In fact, many solutions were introduced to reduce the CCI accompanied with improving network capacity such as using MIMO scheme or SAIC scheme. The paper describes a novel receiver model which provides better performance than that of a SAIC system as well as smaller size and cost than a MIMO system. This proposed receiver uses two co-located antennas with difference polarizations to improve the total performance of the system. In addition, this receiver can be applied effectively in high-modulation scheme, for instant, 8-PSK modulation format in an EDGE network and /or in presence of more than one dominant interference.

Joint Virtual MIMO and Network Coding Scheme with Superposition ARQ in Relay System

A new two-way transmission protocol termed VMNC-SARQ (Virtual MIMO Network Coding with Superposition ARQ) was proposed in this paper, which could improve throughput efficiency of DF (Decode-and Forward) relay network signally. In first step, two single-antenna nodes send messages to the double-antenna relay station simultaneously by using a method similar to 2×2 VBLAST (Vertical Bell Laboratories Layered Space Time) system. In step two, relay station processes the decoded signals received from two source nodes through Network Coding, and then broadcasts the combined messages with Alamouti Coding. A novel retransmission strategy will be implemented when demodulation and decoding failure presents. In order to reduce retransmission overhead, we attach the retransmitted packet to the latter normal packet by using higher modulation, and exploit the confidence value of previously error packet to help to recover both packets. Theoretical analysis and simulation results show that the proposed scheme could greatly improve end-to-end throughput efficiency for two-way relaying systems DOI : http://dx.doi.org/10.11591/telkomnika.v12i2.3444

English

English

Spatial Modulation Concept for Massive Multiuser MIMO Systems

This paper presents the concept of spatial modulation (SM) scheme for massive multiuser MIMO (MU-MIMO) system. We consider a MU-MIMO system whereKusers, each equipped with multiple antennas, are jointly serviced by a multiantenna base station transmitter (BSTx) using appropriate precoding scheme at the BSTx. The main idea introduced here is the utilization of the user’s subchannel index corresponding to the precoding matrix used at the BSTx, to convey extra useful information. This idea has not been explored, and it provides significant throughput enhancements in a multiuser system with large number of users. We examine the performance of the proposed scheme by numerical simulations. The results show that as the number of users and the receiving antennas for each user increase, the overall system throughput gets better, albeit at the cost of some degradation in the BER performance due to interantenna interference (IAI) experienced at the receiver. We then explore zero-padding approach that helps to remove these IAI, in order to alleviate the BER degradations.