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MIMO (Multiple-Input Multiple-Output) is a promising technology for increasing the transmission capacity of cellular mobile systems in proportion to the number of antennas in both transmitter and receiver. Due to their physical size, dual-polarized antennas are superior in this system to single-polarized antennas on the transmitter sides. This paper examines a 2×2 MIMO with dual-polarized antennas...
In this paper, we compare capacity performances of three terminal dual-antenna configurations at 2.65 GHz based on extensive 2 by 2 multiple-input multiple-output (MIMO) channel measurements in an urban macrocellular environment. Both noise- and interference-limited scenarios are investigated. Our results show that, on average over the measurement route, the capacity performance is mainly determined...
Efficiently scheduling the optimal multi-user multiple-input multiple-output links presents a considerable challenge since it depends upon accurate knowledge of the multi-user channel state information and involves significant computational complexity. This paper demonstrates a technique for efficiently scheduling based on a few key parameters that describe the physical nature of multi-user propagation...
For automotive applications car to infrastructure wireless communications enable delivering infotainment services such as location based information, voice calls and video streaming. Those services require a reliable high data rate connection which could be provided by cellular LTE which supports channel adaptive MIMO transmission. However, at the automotive side, confined space is available to accommodate...
To derive higher diversity effect, the simultaneous use of direct (and/or regenerative relay-aided) and nonregenerative relay-aided links is sometimes useful. This paper studies on fundamental aspects of “dirty signal using (DSU)”, a spatial diversity scheme utilizing both clean signal from the source and noise corrupted “dirty signal” from the AF (amplify-and-forward) relay. The conditions under...
Multiple Input Multiple Output (MIMO) delivers service simultaneously to more than one user which adds a new dimension, the spatial one, to be optimized in Cognitive Radio (CR). In this paper, statistical optimization techniques are carried out to assess the system performance where each type of users has different Quality of Service (QoS) demands. Closed form expressions are derived for different...
In this paper, the optimal analog network coding strategy (or relay beamforming) in MIMO two-way relay channels is studied. The weighted sum rate is used as the optimization criterion. Motivated by the classic Arimoto-Blahut algorithm, an iterative algorithm, which monotonically improves the cost function, is designed to update the relay beamformer. This relay beamforming algorithm is further extended...
This paper considers multi-antenna downlink communication with base stations (BSs) that perform joint transmitter null-space decomposition (JT-decomp) and conventional single-cell linear precoding strategies under imperfect channel state information (CSI). Upper bounds for the rate loss of JT-decomp precoding and conventional cellular systems are first provided, which demonstrate that unlike conventional...
We consider a network of K interfering transmitter-receiver pairs, where each node has N antennas and at most one beam is transmitted per user. We investigate the asymptotic performance of different beamforming strategies, as characterized by the slope and y-axis intercept (or offset) of the high signal-to-noise-ratio (SNR) sum rate asymptote. It is known that a slope (or multiplexing gain) of 2N-1...
In this paper, we propose a cooperative beamforming (CB) technique for dual-hop amplify-and-forward communication in WSNs with one source, N - 1 interferences, and K relay nodes. First, an optimal beamformer is obtained that maximizes the signal-to-interference-plus-noise ratio at the intended receiver in the far-field subject to the following constraints: 1) The relay nodes total transmit power is...
In this paper, we consider multi-input multi-output (MIMO) two-way relay networks with orthogonal frequency-division multiplexing (OFDM) modulation scheme. The networks consist of two end users exchanging their information via a relay. One information exchange between two end users is divided into two Phases. In Phase 1, two users send their information to the relay. The relay then amplifies and broadcasts...
The problem of maximizing the sum-rate of a MIMO interference channel is investigated. Each receiver node is assumed to perform single user detection by treating interference from other users as Gaussian noise. It is assumed that all the users share a single frequency band and no pre-coding is performed over time. The sum-rate maximization in such a setup is a longstanding open problem due to its...
The major problem of multiuser MIMO precoding and scheduling is the required Channel State Information (CSI) at the base station which needs to be provided to the base station via a feedback channel in case of frequency division duplex. Each user quantizes the channel direction information and computes a Channel Quality Indicator (CQI), e.g., based on the Signal-to-Interference-and-Noise Ratio (SINR),...
Nonregenerative relaying in MIMO multi-relay networks is analyzed under the general operating scenario of independent but not necessarily identically distributed (i.n.d.) Rayleigh fading. Exact closed-form expressions are derived for the moment generating function of the end-to-end signal-to-noise ratio (SNR) with distinct average received SNRs in each link. Our analysis applies to arbitrary L number...
In this paper, a Forward Error Coded (FEC) Decision-Directed (FEC-DD) channel estimation scheme is proposed for Multiple-Input Multiple-Output (MIMO) Orthogonal Frequency Division Multiplexing/Space Division Multiple Access (OFDM/SDMA) systems which is based on the Expectation-Conditional Maximization Either (ECME) algorithm. The proposed DD technique is combined with the Optimised Hierarchy Reduced...
Block diagonalization (BD) is an attractive method for approaching sum capacity in multiuser multiple-input multiple-output (MIMO) broadcast channels. However, when channel state information (CSI) is limited, the performance of the BD is degraded because inter-user interference cannot be completely eliminated. In this paper, we study limited feedback systems for the BD where a large number of users...
We analyze the asymptotic performance of rate adaptation for Transmit Antenna Selection (TAS) and Maximum Eigenmode Beamforming (MEB) schemes in Multiple-Input Multiple-Output (MIMO) systems under imperfect channel state information (CSI) and feedback delay. The rate is adapted according to a target outage probability. We derive lower and upper bounds to this rate. We also asymptotically characterize...
In this paper, we apply General Order Statistics (GOS) theorem to multi-antenna (MIMO) dual-hop amplify-forward fixed-gain cooperative relay network. General order link, unlike the best one, is selected for the transmission/receiving at each hop. The closed-form expressions of SNR (Signal-to-Noise-Ratio) statistics such as CDF (Cumulative Distribution Function), PDF (Probability Density Function),...
The V-BLAST (Vertically-layered Bell Laboratories Layered Space-Time) algorithm is a multilayer symbol detection scheme. The proposed work focuses on V-BLAST technique with a Multiple Input Multiple output (MIMO) technology followed by receiver detection techniques like Zero forcing (ZF), Minimum Mean Square Error (MMSE) with back substitution SIC (Symbol Interference Cancellation). The proposed methodology...
In this paper, a Gaussian multiple input multiple output multiple eavesdropper (MIMOME) channel is considered where a transmitter communicates to a receiver in the presence of an eavesdropper. We present a technique for determining the secrecy capacity of the multiple input multiple output (MIMO) channel under Gaussian noise. We transform the degraded MIMOME channel into multiple single input multiple...
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