Search

Offset spatial modulation (OSM) is an attractive multiple-input–multiple-output (MIMO) transmission scheme, which alleviates the switching frequency limitation of the radio frequency chain in the spatial modulation technology. In this article, we investigate the bit error performance of OSM in the presence of imperfect channel estimation toward a practical transmission scenario. More specifically, with the aid of union bound technique, a general performance analysis framework of the OSM system with channel estimation errors is proposed. Based on the above analysis framework, the upper bounds of bit error rate for the static and dynamic modes of OSM are both derived, respectively. Finally, simulation results demonstrate that the analytical bounds are tight for a wide range of signal-to-noise ratio (SNR) and variable system configurations., QC 20220216

We study the State-Dependent Gaussian Z-Interference Channel (SDG-ZIC), with two senders transmitting two independent messages through a Gaussian Z-interference channel with the same state. Transmitter 1 interferes with receiver 2, while transmitter 2 does not interfere with receiver 1. In addition, both receivers suffer from the same but differently scaled random state sequence, which is non-causally known at both transmitters. As mentioned in [1], the challenge here is to fully cancel differently scaled states at both receivers. Proposing transmission schemes based on nested lattice codes, we show that under some new conditions, the state at both receivers can be fully canceled and the capacity region can be fully achieved., QC 20190611

In this paper we study cognitive radio networks with secrecy constraints on the primary transmission. In particular we consider several transmission schemes for the secondary transmitter, namely interference neutralization (IN) and cooperative jamming with and without clean relaying (CR). We derive and analyze the achievable secondary rate performance of the schemes. Furthermore we thoroughly investigate the advantages and shortcomings of these schemes through numerical simulations in a geometric model where we highlight the impact of the users' locations and show the important difference in all schemes depending on the topology. Our results show that the secondary transmitter can successfully adapt its transmission scheme (and parameters), i.e., either IN or CR, depending on its location to maximize its rate while insuring perfect secrecy of the primary transmission., QC 20160314

Secret key establishment leveraging the physical layer as a source of common randomness has been investigated in a range of settings. We investigate the problem of establishing, in an information-theoretic sense, a secret key between a user and a base-station (BS) (more generally, part of a wireless infrastructure), but for two such user-BS pairs attempting the key establishment simultaneously. The challenge in this novel setting lies in that a user can eavesdrop another BS-user communications. It is thus paramount to ensure the two keys are established with no leakage to the other user, in spite the interference across neighboring cells. We model the system with BS-user communication through an interference channel and user-BS communication through a public channel. We find the region including achievable secret key rates for the general case that the interference channel (IC) is discrete and memoryless. Our results are examined for a Gaussian IC. In this setup, we investigate the performance of different transmission schemes for power allocation. The chosen transmission scheme by each BS essentially affects the secret key rate of the other BS-user. Assuming base stations are trustworthy but that they seek to maximize the corresponding secret key rate, a game-theoretic setting arises to analyze the interaction between the base stations. We model our key agreement scenario in normal form for different power allocation schemes to understand performance without cooperation. Numerical simulations illustrate the inefficiency of the Nash equilibrium outcome and motivate further research on cooperative or coordinated schemes., QC 20160104

In this paper we study secure communications with weak secrecy constraint in a cognitive radio channel, where the secondary receiver is treated as a potential eavesdropper with respect to the primary transmission. The primary's secrecy rate and the transmission scheme should be kept unchanged whether the secondary users transmit or not. We derive the achievable rate of the discrete memoryless multi-phase cognitive channel. To against the information leakage due to the use of Gelfand-Pinsker coding at the secondary transmitter, we derive the corresponding constraints to guarantee the primary's secure transmission. We then specialize the results to the additive white Gaussian noise channels. Numerical results show the advantages of using the proposed multiple-phase transmission scheme over the traditional ones without the additional phase., QC 20160314

Transmission schemes for flat multi-input, multi-output (MIMO) channels are well established for the cases where perfect channel state information or no channel state information is available at the transmitter. However, communication over channels where the transmitter has access to partial or imperfect information has received less attention. If exploited, such information has the potential of improving system performance and reducing the bandwidth requirements of feedback links or the required quality of channel estimates. Herein, a simple design scheme is introduced, that approximately maximizes the data rates of MIMO communication systems where the transmitter has access to partial channel state information in the form of covariance feedback or erroneous channel estimates. An algorithm is presented which is computationally attractive and performance gains are shown when compared to systems not using this information., QC 20161129

We consider a cooperative cognitive radio network with one primary user and many secondary users. In each transmission frame, one secondary user is selected to act as a relay for the primary user and also transmits its own data. Three different schemes for the secondary user's transmission is studied, namely, time-splitting, superposition coding, and a combined scheme that takes advantages of both time-splitting and superposition coding schemes. We formulate the relay selection problem for each scheme with the objective of maximizing the secondary user's data rate while satisfying a pre-defined gain threshold for the primary user. This constraint provides an incentive for the primary user when allowing the secondary user access its licensed band. We obtain the optimal solution for this problem in each scheme, on which the relay selection is based on. Finally, we compare the performance of different schemes using Monte-Carlo simulations., QC 20140312, Mobile and wireless communications Enablers for Twenty-twenty (2020) Information Society (METIS)

This paper considers joint transceiver design and power control for K-user multiple-input multiple-output (MIMO) interference networks. Each source intends to communicate with its corresponding destination at a fixed data rate. Only local channel side information (i.e. knowledge related to the channels directly connected to a terminal) is available at each terminal. We propose iterative algorithms to perform power control to guarantee successful communication while designing transmitter beamforming matrices and receiver filtering matrices according to the interference alignment concept. The proposed algorithms can exhibit a substantial performance improvement compared to the conventional orthogonal transmission schemes., QC 20130424

We consider a downlink two-hop MISO broadcast network with a 2-antenna source communicating to 2 singleantenna destinations, assisted by 2 single-antenna intermediate relays. We investigate spectrally efficient transmission schemes and their achieved sum degrees of freedom (DoF), with quantized delayed channel state information (CSI) feedback. Assuming Grassmannian vector quantization, we study two feedback scenarios according to the feedback range limit, namely global-range feedback, i.e., the source can receive the feedback signals from both the relays and the destinations, and one-hop-range feedback, i.e., each node can only attain the feedback information of its upcoming hop. We establish a sum DoF lower bound for each case. Our results reveal that when the quantization rate at relays BR= α1log2(SNR) and at destinations BD = α2log2(SNR) for min {α1, α2} ≥ 1, the optimal sum DoF 4/3 can be achieved with finite-rate delayed feedback., QC 20121207

A transmission scheme for mean square stabilization of two linear systems over a Gaussian interference relay channel is studied. A delay-free linear sensing and control strategy is proposed and an achievable stability region is derived. It shows that the stability region can be significantly enlarged by deploying a relay node in such a multi-user Gaussian channels. Furthermore we observe that the separation structure between estimation and control is inadequate in high interference regime., QC 20140121

We consider the problem of remotely controlling an unstable first-order noiseless linear plant over a discrete symmetric memoryless channel using anytime source-channel coding. We propose a transmission scheme, exploiting unequal error protection (UEP) based on Luby transform (LT) codes under sequential belief propagation (BP) decoding. Sufficient conditions on mean square stability of the linearly controlled closed-loop system are derived for the anytime UEP-LT codes., QC 20120730

[EN] A new transmission scheme for OFDM systems that uses the odd discrete Fourier transform to provide frequency diversity gain is proposed. Odd DFT allows the transmission of data subcarriers in frequencies that are centred between those employed by the traditional DFT. This fact is exploited to transmit data subcarriers on the group of frequencies that gives better performance using either traditional DFT or odd DFT. As an example, by using this approach a diversity gain up to 5.3 dB at a BER of 10-4 in a typical indoor channel model can be achieved. © 2011 The Institute of Electronics, Information and Communication Engineers.

This paper concerns the design of codes for multiple-input multiple-output communication systems. The transmission scheme utilizes imperfect channel state information (CSI) in the design, assuming that maximum-likelihood detection is employed at the receiver. It is argued that channel diagonalizing codes are not robust to imperfections in the CSI. A robust non-diagonalizing code with good minimum distance separation between received codewords is proposed. The design is very suitable for systems operating at high data rates since the complexity scales nicely with the number of antennas. Numerical results show that the proposed code outperforms a state-of-the-art diagonalizing precoder., QC 20141104