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Interference alignment (IA) effectively improves the capacity of interference channel by overlapping the interference and eliminating at the receivers. At present, most algorithms of the distributed interference alignments design precoder and receiver filter at both transmitters and receivers which causes overhead. This paper presents an improved interference alignment based on minimizing projector...
In this paper, considering the problem of performance loss due to limited feedback in multiuser MIMO downlink systems, a novel limited feedback precoding for multiuser MIMO systems based on array preprocessing is proposed. The maximum SINR criteria is used for selecting optimal codeword from the Grassmannian codebook and perturbation codeword at the receiving, and feedback the Grassmannian precoding...
Multi-user multiple input and multiple output (MU-MIMO) is one of the key techniques in 3GPP Long-Term Evolution (LTE), which enhances the overall system capacity in the downlink. In order to reduce the effect of inter-user-interference in this system, it is necessary to utilize an efficient detection method at the user equipment (UE) that besides its feasibility at high data rate transmission systems...
In this paper, performance of a novel analytic model of direct sequence code division multiple accesses (DS-CDMA) using diversity with maximal ratio combining (MRC) scheme is observed under the influence of multipath Rayleigh fading and multi-access interference (MAI) varying different system parameters and properties of PN sequences. The analysis presents a mathematical expression for bit error rate...
In this paper, an order reduction maximum likelihood (OR-ML) algorithm for spatial modulation systems is proposed to reduce the receiver complexity. The proposed algorithm relies on a smaller order neighbourhood constellation which is relative to the conventional mapping constellation, where the active transmitting antenna indices or the possible quadrant transmission symbols locate in is obtained...
Long Term Evolution (LTE) is a standard for wireless communication of high speed data for mobile phones and data terminals. LTE is capable of delivering large data rate on the order of several megabits per second, which is even larger than the current 3G systems. This is very challenging as the wireless networks are subjected to interference, multipath and poor propagation channel characteristics...
In this paper, we elaborated on a new interference alignment technique for downlink multi-user system in a MIMO-X channel with multiple antennas. We considered two transmitters, each equipped with M antennas, and L users, each equipped with K antennas. Here, we consider a MIMO-X scenario that some users are receiving transmissions from both transmitters. The proposed approach is focused on rank-1...
This paper investigates the performance enhancements using radio-frequency (RF) beamforming on closely spaced antennas in multiple-input multiple-output (MIMO) communication system. Of specific interest is the case of a array of extremely closely spaced antennas with complexity constraints, here implemented being restricted to a single RF chain. Our system model is developed in context of closely...
This paper reports a research testbed of real-time ultra-wideband (UWB) multiple-input multiple-output (MIMO) radio. In the receiver design, the UWB MIMO receiver supports up to eight channels, where each channel is equipped with an analog-to-digital converter (ADC) with 8-bit resolution and sampling rate up to 3 Giga samples per second (Gsps). The transmitter is able to transmit two independent arbitrary...
In this paper, we propose an efficient link adaptation scheme for the 3GPP Long Term Evolution Advanced (LTEA) uplink with turbo successive interference cancelation (Turbo-SIC) receiver and imperfect channel estimation. Link adaptation for non-linear MIMO receivers such as Turbo SIC is not straightforward because the soft-outputs of such receiver cannot be simply modeled using a scalar Gaussian channel...
We analyze a sub-optimum transmit antenna selection (TAS) scheme in multiple input single output (MISO) systems equipped with I transmit antennas. We keep one antenna fixed and select the best among the remaining N - 1 antennas. We assume spatially independent flat fading channel with perfect channel state information (CSI) at receiver and an ideal feedback link. We use Alamouti transmit diversity...
This paper examines a type of linear beamforming for communications in interference networks. First, a receiver beamformer design is derived from a Maximum Likelihood (ML) framework with Automatic Gain Control (AGC) constraints. The studied beamformer keeps the complexity of the receiver low and it is able either to remove full coherent arrivals or to enhance them when required when different AGC...
It is well-known that for single-input and single-output (SISO) narrow-band transmission on frequency-flat fading channels, uncoded communication with only receiver channel state information (Rx-CSI) leads to extremely poor reliability performance whereas transmitter CSI (Tx-CSI) allows us approach the reliability of an additive white Gaussian noise (AWGN) channel via power control. In this paper,...
Multiple antenna techniques are used to enhance wireless links and therefore have been studied extensively. Many practical systems differ from ideal schemes which have been discussed in the literature. One example is a system that lacks precise channel information at the transmitter. We evaluate analytically the performance of a multiple input multiple output (MIMO) technique that uses partial channel...
This paper presents a deterministic modelling approach to predict diffraction loss for an innovative Multi-User-Single-Antenna (MUSA) MIMO technology, proposed for rural Australian environments. In order to calculate diffraction loss, six receivers have been considered around an access point in a selected rural environment. Generated terrain profiles for six receivers are presented in this paper....
In this paper, we derive the optimal structure of the source precoding matrices and the relay amplifying matrix for a two-way amplify-and-forward multiple-input multiple-output (MIMO) relay communication system where linear minimal mean-squared error (MMSE) receivers are used at both destinations. We show that for a broad class of frequently used objective functions for MIMO communications, the optimal...
A virtual multiple-input multiple-output (MIMO) system based on cooperative communication is studied actively. This system is formed between base station and source node with using of two or more nodes around itself. These transmitters are equipped with a single antenna. This system is one of the solution methods for deterioration in communication quality from that the power supply of the node is...
In this paper we examine the use of generalized singular value decomposition (GSVD) for coordinated beamforming in MIMO systems. GSVD facilitates joint decomposition of a class of matrices arising inherently in source-to-2 destination MIMO broadcast scenarios. GSVD allows two channels of suitable dimensionality to be jointly diagonalized, i.e. to be reduced to non-interfering virtual broadcast channels,...
The Golden Code is a full-rate full-diversity space-time code, which achieves maximum coding gain for Multiple-Input Multiple-Output (MIMO) systems with two transmit and two receive antennas. Since four information symbols taken from an M-QAM constellation are selected to construct one Golden Code codeword, a maximum likelihood decoder using sphere decoding has the worst-case complexity of O(M4),...
In this paper a novel detection algorithm for spatial modulation (SM) based on sphere decoder (SD) tree search idea is proposed. The aim is to reduce the receiver complexity of the existing optimal decoder while maintaining an optimum performance. The algorithm performs a maximum likelihood (ML) search, only over those points that lie inside a sphere, centered at the received signal, of given radius...
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