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An enlargement of candidate vector set of QR-LRL (QR — Least Reliable Layer) based MIMO detector for efficient soft output generation is proposed. Previous work [8] shows that QR-LRL based MIMO detector approaches hard decision output ML performance, but does not match the soft output ML performance due to empty candidate vector set problem. Performance degradation is more severe when modulation order...
In this study, the performance of tracking and data relay satellite (TDRS) communication system multiple access (MA) service is analyzed. Firstly, in order to eliminate multiple access interference, a multiuser detector based on minimum mean square error (MMSE) and artificial fish swarm algorithm (AFSA) is explored. The result of MMSE and its modified formations are used as the initial values of artificial...
In this paper, we investigate channel estimation for Interleave-Division Multiple Access (IDMA) in an asynchronous multiuser system, by deploying superimposed pilots. As the superimposed pilots are the a priori known spreading sequences, the initial channel estimates can be obtained by separating the users with respect to the corresponding code-division orthogonality. Within the inherent IDMA iterations,...
We investigate iterative detection and decoding, a.k.a. turbo detection, for multiple-input multiple-output (MIMO) transmission. This investigation is based on a low complexity softoutput MIMO detector with a priori information feedback. We show that maximum a posteriori performance (without turbo iteration) can be achieved, at a much lower computational cost, by using the proposed soft-output MIMO...
Code division multiple access (CDMA) is one of the promising techniques in cellular mobile communications system used for radio accessing and personal communication systems. Besides several practical advantages, CDMA suffers with multiuser interference, limiting the spectral efficiency drastically. There are various optimal and suboptimal multi user detection techniques in CDMA to overcome this problem...
In this paper we propose robust watermarking schema for video files based on spread spectrum theory. The main concept relies on utilization of time as temporal dimension for spreading of watermark bits that are assigned to video frames. The second level spreading that is impartial to first level, uses different set of PN sequences within the video frames what allows to utilize multiple watermarking...
An iterative detection and decoding (IDD) scheme based on component-level soft cancellation (CLSC) and linear minimum mean-squared error (LMMSE) filtering for turbo coded multiple input multiple output (MIMO) multiplexing systems is proposed in this work. By exploiting the independence between the In-phase and Quadrature-phase branch, more accurate soft interference cancellation is realized. Extrinsic...
An improved iterative receiver is developed for multiuser communications using fast frequency-hopping modulation. Each user employs a channel encoder to protect its information and facilitate interference cancellation at the receiver. At the destination, in order to reliably extract signals from all users, the detection algorithm employs double iteration process: an outer iteration between the interference...
The ability to avoid detection of a communication signal in the underwater acoustic channel is extremely important for underwater acoustic communication (UWAC) systems when used for military-related applications. Furthermore, low probability of detection (LPD) may reduce environmental impact of UWAC as communication signals can be transmitted at lower power. In this paper, we study the LPD capability...
This paper deals with MIMO detection for rank 4 3GPP Long-Term-Evolution (LTE) systems. The paper revolves around a previously known detector [1], which we shall refer to as RCSMLD (Reduced-Constellation-Size-Maximum-Likelihood-Detector). However, a direct application of the scheme in [1] to LTE/LTE-A rank 4 test cases results in unsatisfactory performance. The first contribution of the paper is to...
The challenges in satellite communication (SatCom) include but not limited to the customary complications of telecommunication such as channel condition, signal to noise ratio (SNR), etc. SatCom system is also prone to transient and permanent radiations hazards. Hence, in spite of the harsh environmental factors (weather phenomena, solar events, etc), a SatCom system must maintain reliable and predictable...
This paper proposes 2×2 MIMO OQAM/FBMC receiver strategy based on successive interference cancellation (SIC) as an extension of the SISO approach which uses entirely real-valued formulation of the transmission system model]. Both increase of throughput and SNR gain are observed through appropriate maximum ratio combining (MRC) of the soft symbols pertaining to the receiver-end diversity branches....
This paper proposes a 2D code and its decoding method robust against non-uniform, complicated distortions, assuming an application to automatic recognition of a plastic garbage bag. Printing a 2D code on a garbage bag is a promising approach for automatic bag recognition from the perspective of information content and cost. However, a 2D code printed on the bag causes non-uniform distortions because...
In this work, a transmission scheme that combines multi-layer multi-rate (MLMR) coding with quasi-orthogonal space-time block coding (QO-STBC) is proposed. Firstly, the proposed QO-STBC codewords set unequal diversity orders for different transmitted spatial data layers. Then, different spatial data layers are protected by different-rate channel codes with the aim of achieving the same post-decoding...
This paper introduces a novel class of linear soft-input soft-output detectors with boosted communications performance. The detector showed an SNR gain of up to 2.4 dB compared to state-of-the-art linear detectors. We introduce a low-complexity algorithm tailored for VLSI implementation, and propose a suitable architecture. The developed ASIC demonstrates the feasibility and efficiency of the concept,...
In this paper, we study iterative detection algorithms of the multi-cell multi-user massive MIMO systems with pilot contamination. First, a iterative algorithm applying soft decision interference cancellation is introduced. It is based on minimum mean square error (MMSE) filter and derived from [1] where it was applied in block transmission. Then, by considering the algorithm complexity, two iterative...
A computational complexity analysis of matrix inversion used in soft-input soft-output minimum mean square error (MMSE) MIMO detectors and a comprehensive literature comparison of corresponding VLSI implementations are presented. They indicate that the application specific integrated circuit (ASIC) proposed in this paper is — to the best of our knowledge — the most area-throughput efficient VLSI architecture...
In this paper, the combination of a low-complexity Multiple-input Multiple-output based on belief propagation (MIMO-BP) detector with a Non-Binary Low-Density Parity-Check (NB-LDPC) decoder is investigated. Such detection and decoding algorithms can enable an equivalent representation based on a larger Joint Factor Graph (JFG). Shuffle schedule can therefore be used jointly and simultaneously on the...
In this paper, we firstly attempt to design initial acquisition schemes for wideband DVB-S2 based time slice transmission that was published recently. This provides the essential guideline to learn frame detection design for time slice DVB-S2 reception.
A novel reduced-complexity soft-input soft-output minimum mean square error detection algorithm for MIMO systems together with an area-throughput efficient VLSI architecture is described. A detailed comparison to related work is presented. The proposed VLSI architecture of the novel algorithm represents — to the best of our knowledge — the most area-throughput efficient SISO MIMO detector ASIC reported...
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