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In this paper, we will propose a framework for computing detection (Pd) and false alarm (Pfa) probabilities for chip-time differential transmitted-reference (Tc-DTR) receivers over frequency-selective multipath fading channels further impaired by narrow-band interference (NBI). We will show that, when compared to similar non-coherent receiver architectures, Tc-DTR offers an intrinsic robustness to...
Military applications often require traffic to be multicast to a group of receivers. It has previously been shown that linear network coding is useful in conjunction with physical-layer multicasting for reliable multicast delivery over fading channels. Superposition coding is an effective way to deliver information to a single receiver over a fading channel. However, we have shown in previous work...
In wireless networks, communication links may be subject to random fatal attacks: for example, sensor networks under sudden power losses or cognitive radio networks with unpredictable primary user spectrum occupancy. Under such circumstances, it is critical to quantify how fast and reliably information can be collected over attacked links. In our previous work, we studied such channels by considering...
This paper proposes a low-complexity equalizer for orthogonal frequency division multiplexing (OFDM) systems under time-varying frequency-selective fading environments. The equalization uses suboptimum maximum likelihood sequence estimation (MLSE) in cooperation with semi-blind linear prediction (SBLP) in the estimation of the channel frequency responses. When the number of pilot subcarriers is far...
In our previous work, we have shown that hybrid ARQ (HARQ) can be used to achieve secret communication over a fast fading channel. This is a physical-layer technique that can be used in conjunction with conventional cryptography to provide further protection from an eavesdropper. The key to our previous work was to use reliability-based HARQ to improve the decoder performance at the desired user much...
The majority of prior work in signal-to-noise ratio estimation makes fairly strong assumptions concerning a priori knowledge of the channel state and signal. For instance, many of these estimators assume knowledge of the modulation scheme of the signal, or even complete knowledge of the transmitted set of modulated data symbols (typically through the use of training sequences). Even more universally,...
We consider a physical layer security based on the wiretap channel for wireless communication systems in which there are one transmitter and multiple receivers/users who report their channel state information (CSI) to the transmitter. This scenario is practically useful since it models the forward link of cellular systems where the systems can take advantage of the multiuser diversity. We are curious...
Multiple input multiple output (MIMO) space time codes are used to increase the diversity or the number of degrees of freedom for improving the capacity (data rate) and reliability (error rate) of wireless communication over fading channels. In this paper, we propose a new structure of space time code designed for non-stationary constant-amplitude modulation formats using polynomial phase signals...
In this paper we study the problem of active eavesdropping in fast fading channels. The active eavesdropper is a more powerful adversary than the classical eavesdropper. It can choose between two functional modes: eavesdropping the transmission between the legitimate parties (Ex mode), and jamming it (Jx mode) - the active eavesdropper cannot function in full duplex mode. In this paper we only consider...
We study the use of node cooperation as a way to improve performance in multiple-source, single-destination wireless networks that use scheduled access as the channel-access method. Unlike many other studies of scheduled access, which are based on the use of a collision channel, we use a physical channel model that incorporates other-user interference, fading, and background noise. The characteristics...
This paper proposes a scheme of continuous phase modulation (CPM) receivers using frequency domain equalization and conventional parallel and serial CPM receiver structures. Frequency domain equalizers for CPM block transmissions provide spectral and power efficient wireless communications with less complexity than conventional time-domain processing receivers over frequency selective fading channels...
Opportunistic Spatial Orthogonalization (OSO), first proposed in Shen and Fitz (2009) for the single-input-multiple-output (SIMO) system, is a cognitive radio scheme that opportunistically allows the existence of secondary users even if the primary user occupies all the frequency bands all the time. On one hand, OSO can be viewed as a multi-user diversity scheme that exploits the channel randomness...
The problems of resource allocation and the characterization of cooperative behavior in a two-user fading multiple-access channel (MAC) in the presence of uncertainty about the channel state information at the transmitters (CSIT) are considered. Game-theoretic techniques are used to characterize cooperative behavior and obtain the system operation point from an individualistic perspective. A two-user...
Mobile satellite communications are affected by signal distortions that are negligible in traditional, fixed SATCOM applications. These distortions include delay and Doppler spread multipath that exhibit significant variations over a relatively short period. Accurate modeling and emulation of the fast fading multipath requires substantially different techniques than the slow fading models traditionally...
This paper proposes a three-dimensional (3-D) model for narrowband multiple-input multiple-output (MIMO) vehicle-to-vehicle (V-to-V) multipath fading channels that accounts for mutual coupling among both, transmit and receive antenna elements. This model is used to evaluate the effect of mutual coupling on the antenna element patterns and capacity of MIMO V-to-V systems in a variety of urban environments.
Multicarrier (MC) CDMA systems have been developed and rapidly gained popularity as they capitalize on both MCM (multicarrier modulation)'s resilience to multi-path fading and direct-sequence (DS) CDMA's simplicity in multi-access and synchronization design to mitigate both multiple access interference (MAI) and the inter-symbol interference (ISI) caused by time dispersive channels with the aid of...
Motivated by the operational need of eliminating the potential single point of failure (SPOF) of a communications network, a cooperative team communication (CTC) approach is proposed for distributed, wireless sensor and team networks. We assume that the communication system uses a spread spectrum waveform, and each radio implements the Rake processing capability to combat channel fading effects. The...
We introduce a new interference management technique for wireless cellular networks when the base station (BS) has K antennas and there are M mobile stations (MS), each with a single antenna. Our interference management scheme takes advantage of multiuser diversity to transmit K independent data streams to K out of M mobile stations. The new approach achieves the dirty paper coding (DPC) capacity...
A framework for multiple access protocols supporting the admission and sustenance of concurrent transmissions in Gaussian interference channels (G-IC) encountered in opportunistic unstructured networks or unused spectral bands under quasi-static fading is proposed. Each node is assumed to be equipped with successive decoding capabilities and seeks admission to the network by requesting a minimum rate,...
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