The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In the previous works on multiple-input multiple-output (MIMO) interference channels, it is usually assumed that the transmit power is fixed and only MIMO beamforming is applied to mitigate interference. In this paper, we design the transmit powers and beamforming vectors jointly for each transmit-receive pairs (links) to maximize the energy efficiency in MIMO interference channels. Centralized and...
Transmission of signals using multiple antennas can significantly improve the energy efficiency of a wireless network, and the proper alignment of the transmitted signals' phases at the receiver is one of the key factors so this efficiency improvement can be realized. In a time-varying channel, due to the relative motion between the transmitters and the receiver, the development of a scheme that guarantees...
In this paper, we study the performance of the Regularized Channel Inversion (RCI) precoder in a multi-user MIMO system with malicious users. We consider the general case when the number of users per transmit antenna β can take any value. We derive the optimal regularization parameter that maximizes the achievable secrecy sum-rate via large-system analysis, which we show to be accurate via simulations...
In this paper we consider the coexistence of a single-input single-output (SISO) primary link with a multiple-input single-output (MISO) secondary user pair that has non-causal knowledge of the primary message. We study an achievable rate region that exploits this knowledge by combining selfless relaying to maintain the rate supported by the primary link with dirty paper coding to pre-cancel the interference...
In this paper, we study adaptive transmission mode switching between statistical and instantaneous channel state information (CSI) aided single-user (SU) and multiuser (MU) precoding for a two-user downlink system, where two transmit antennas are equipped at the base station and each mobile user has one receive antenna. In the case where only statistical CSI (SCSI) is available at the transmitter,...
This paper investigates the impact of noise dependence and signal delay on the capacities of networks. It is shown that statistical dependence between the noise in a network's component channels is helpful for communication. In particular, the capacity region of a network whose component channels exhibit dependent noise is a superset of the capacity region of a network built from the same component...
This paper studies the achievable performance of a single-antenna spectrum-sharing system. Due to limited cooperation between secondary users (SUs) and primary users (PUs), perfect channel state information (CSI) related to the PUs is hard to obtain for the SUs. Therefore, we assume the secondary transmitter and receiver have only statistical CSI from the secondary transmitter to the primary receiver...
This paper investigates the outage performance of dual-hop amplify-and-forward (AF) two-way relaying systems with multiple co-channel interferers at the AF relay and two noisy end-sources. Assuming a Nakagami-m fading environment, a highly precise, easy-to-compute closed-form approximate expression for the outage probability is derived. Our analysis allows for general operating scenarios with distinct...
In this paper, we investigate the achievable rate and ergodic capacity of a general non-symmetric half-duplex non-orthogonal amplify-and-forward (NAF) single-relay channel in Rayleigh fading environments, assuming that the channel state information is only available at the destination. The considered channel, which captures pathloss and shadowing effects over the transmission links, includes the symmetric...
This paper investigates a new constrained relay selection scheme for two-way relaying systems where two end terminals communicate simultaneously via a relay. The introduced technique is based on the maximization of the weighted sum rate of both users. To evaluate the performance of the proposed system, the outage probability is derived in a general case (where an arbitrary channel is considered),...
Wireless communication is prone to errors due to always changing channel conditions. Multiple transmissions over independent channels can be leveraged by combining erroneous packets. To be able to combine, reliability information for bits, so-called soft-bits, of the previous messages has to be saved. Especially for systems with limited storage capacity, such as sensor nodes, this poses the question...
We present a novel combinatorial geometrical approach for evaluating the performance of multidimensional finite lattice constellations in Additive White Gaussian Noise (AWGN). More specifically, we present an analytical expression for the exact symbol error probability (SEP) of multidimensional signal sets, which is then used to derive a tight closed-form lower bound of the SEP, named Multiple Sphere...
Cooperation among nodes is proposed as an effective means of combating fading and for enhancing system's overall capacity and coverage. The robustness of rateless codes makes them particularly attractive for such networks. Yet, the decoding aspects of rateless codes are discarded in most of the traditional distributed networks. In this paper, the intermediate packet decodability of rateless codes...
In this paper, we propose a novel method suitable for unequal error protection(UEP) and unequal recovery time (URT) properties, namely the Duplicating-Expanding Window Fountain(D-EWF) codes. We implement duplicating windows and expanding windows techniques to improve the performance of both more important bits (MIB) and less important bits (LIB). We analyze the proposed method over binary erasure...
3GPP long term evolution (LTE) Turbo coded modulation is well-known for its excellent error-control capability. However, its decoding threshold is still a few decibels away from the constellation-constrained capacity. In this paper, an irregular mapping scheme involving labeling search is proposed to improve the performance of the LTE system. The scheme first predetermines one labeling, and then searches...
This paper presents a comparison between two transmit diversity schemes, namely space-time coding and time-switched transmit diversity (TSTD) over block-fading and time-varying multi-input single-output (MISO) channels with various channel parameters. The schemes are concatenated with outer channel codes in order to achieve spatio-temporal diversity. The analytical results are derived for the error...
Recently, Delay-Tolerant Space-Time Codes (DT-STCs) have been designed for cooperative communications. They are optimal in synchronous transmission and preserve their full-diversity order for arbitrary delays in asynchronous case. In this paper, we investigate these DT-STCs in femtocell networks where Femtocell Access Points can assist Macrocell Base Stations to transmit data information to users...
This paper presents a category of detection schemes for Multiple-Input Multiple-Output (MIMO) system called Parallel Sphere Decoder (PSD). Compared to the conventional depth-first sphere decoder with Schnorr-Euchner enumeration (SE-SD), the proposed PSD algorithms use parallel computations and achieve approximately 50% searching time reductions under the same amount of computations. Namely, in hardware...
We present a new 4×4 Hadamard-precoded Quasi-Orthogonal Space-Time Block Code (QO-STBC) that enables reliability-based prioritized symbol detection using linear filters. Approximate block-error-rate analysis is carried out and used to optimize the code rotation angles. For benchmarking purposes, the maximum-likelihood (ML) code detector is also derived with complexity of the order of joint two-real-symbol...
The fixed-complexity sphere decoder (FSD) has been proposed to attain the near-optimal performance achieving the same diversity order as the maximum-likelihood decoder (MLD) recently. However, it suffers great redundant computations resulting in high power consumption. In this paper, we conduct an improved algorithm for the original FSD by using early termination (ET). This algorithm (abbreviated...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.