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This paper presents a novel technique - Multi-Channel Ratio (MCR) Decoding, which aims at providing an anti-jamming wireless communication capability for multi-antenna wireless devices. The basic idea of MCR decoding is to fully leverage the repeated preamble signals and the multi-channel characteristics in MIMO communications to detect and recover the desired transmission signals under constant and...
Automatic Dependent Surveillance-Broadcast (ADS-B) systems provide to the air traffic control centers flight and status information of the cooperating targets. Problems due to jamming and/or spoofing of the ADS-B channel are under study, as well as verification and validation techniques. In this paper, we show how a low cost jammer can affect an ADS-B receiver. Three types of threats were evaluated...
In this paper we address the problem of designing a user selection algorithm in a multiuser multiple-input multiple-output downlink scenario. Linear precoding is adopted at the transmitter and, thus, the number of users to be served at each particular scheduling period is limited by the number of available transmit and receive antennas. The adopted scheduling criterion for the user selection is based...
In order to support high data rate communications, the third generation partnership project (3GPP) long term evolution (LTE) implements multiple-input multiple-output (MIMO) systems. In addition, to achieve excellent performance, LTE also employs turbo codes as the forward error correcting (FEC) standard. Although conventional turbo codes give satisfactory performance in the ideal MIMO, significant...
In this paper, we study a simple X-relay configuration where the shared relay operates in full-duplex (FD) mode. The relay node may have limited spatial degrees of freedom, and as a result, it may not be able to handle both the loop interference and the multiuser interference. Hence, a decision on the precoding scheme is necessitated. It is often the case that the relay does not have the option of...
Algebraic Space-Time Codes (ASTC) for MIMO systems are based on quaternion algebras. Thanks to their algebraic construction, the ASTC codes, called the golden codes, are full-rank, full-rate and have the non-vanishing determinant property. Proposed for MIMO flat fading channels, these codes can increase the spectral efficiency and enhance the coding gain. ASTC codes maintain their proprieties for...
In this paper, we propose an extended version of sphere decoder (ESD) with the MMSE based enumeration for DL MU-MIMO systems. In previous work, we proposed the ESD which detects interference signals additionally. The ESD can achieve near-optimal performance, but it has much higher complexity than the existing SD. Therefore, this paper presents the improved enumeration based on MMSE. The proposed algorithm...
In this letter, we propose a low-complexity adaptive channel state information (CSI) feedback scheme to maximize the throughput in IEEE 802.11ac systems. We analyze the two factors — the interference and the feedback overhead -and develop a method to attain an optimal CSI feedback quantization level with minimal additional complexity. Our numerical results and complexity comparisons verify the efficiency...
In this paper, we propose a new hardware-efficient ML decoding algorithm for a spatial modulation scheme which is basically constructed by serially concatenating maximum-ratio receive combiners with traditional slicers. With respect to complex multiplications, the new algorithm has a greatly reduced decoding complexity compared to the conventional one, especially, for higher-order modulation. This...
Many wireless networks are rapidly become part of our daily life. However, range and data rate in wireless devices are limited. One method is to use Multiple-Input Multiple-Output (MIMO) communication system to overcome these limitations. The multiple antennas allow MIMO systems to perform diversity coding (space-time coding), and spatial multiplexing. Beamforming consists of transmitting the same...
Due to their ability to provide high data rates, multiple-input multiple-output (MIMO) systems have become increasingly popular. Decoding of these systems with acceptable error performance is computationally very demanding. In this paper, we employ the Sequential Decoder using the Fano Algorithm for large MIMO systems. A parameter called the bias is varied to attain different performance-complexity...
In this paper, we propose an expectation propagation based iterative multi-user detection algorithm for multiple input multiple output interleave-division multiple access (MIMO-IDMA) systems with high-order modulation. The proposed detector can be well integrated into the traditional structure of turbo receivers for MIMO-IDMA systems. By formulating a scalar factor graph representation of the multi-user...
A Multiple Input Multiple Output (MIMO) relay assisted wireless communication system encoded with Turbo- VBLAST codes is studied in this paper. Source is equipped with multiple transmit antennas, relay is equipped with multiple transmit as well as receive antennas and destination is also equipped with multiple receive antennas. Turbo encoder encodes the input bits and then QPSK or 16 QAM or 64 QAM...
We introduce a low-complexity decoder with near-optimal performance for transmission over multi-antenna systems. By using lattice basis reduction for generating almost orthogonal channel matrix, we enhance the conditional decoding technique to implement a fast yet efficient decoder. The lattice-reduction-aided conditional decoder is presented as a general detection technique over fading channels to...
MIMO systems has been proved to be one of the most promising and emerging wireless technologies that can efficiently increase the data transmission rate, improves system coverage, and enhances the link reliability. By employing multiple antennas both at transmitter and receiver side, MIMO techniques enables a new dimension-the spatial dimension-that can be utilized in different ways to combat the...
In this work the optimal diversity-multiplexing tradeoff (DMT) is studied for the multiple-input multiple-output fading multiple-access channel with no power constraints (infinite constellations). For K users (K > 1), M transmit antennas for each user, and N receive antennas, infinite constellations in general and lattices in particular are shown to attain the optimal DMT of finite constellations...
Communication over a fading channel in a wireless storage system makes repair transmissions prone to physical layer errors. The repair transmission can be modeled as a multiple access channel (MAC), where multiple helpers are simultaneously communicating to the newcomer node. The existing optimal MAC space-time (ST) codes are, however, practically useless due to exponentially high decoding complexity...
A Gaussian wiretap channel with a helper, i.e., a cooperative jammer, is considered and its secure degrees of freedom (s.d.o.f.) is computed. Previous work showed that the s.d.o.f. is upper bounded by 1 over 2 in this model when all parties are equipped with one antenna each. In this paper, the more challenging scenario where the eavesdropper has multiple antennas is tackled. Relying on structured...
Two principal transmission techniques have been developed to take advantage of Multiple-Input Multiple-Output (MIMO) systems: Spatial Multiplexing and Diversity Transmission. In this paper we are combining space-time block code (STBC) with spatial multiplexing technique over space to take advantages of both schemes. At the receiver, a minimum mean square error (MMSE) detector with interference cancelation...
We consider the problem of the two-user multiple-input single-output complex Gaussian Broadcast Channel where the transmitter has access to delayed knowledge of the channel state information. We characterize the capacity region of this channel to within a constant number of bits for all values of the transmit power. The proposed signaling strategy utilizes the delayed knowledge of the channel state...
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