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Multicell coordinated beamforming, where multiple base stations (BSs) collaborate with each other in the beam-vectors design to mitigate the intercell interference (ICI), has been a subject of great attention recently. With perfect channel information available at the base stations, we first present a fast converging algorithm that solves the weighted sum rate maximization (WSRM) problem. Then, the...
Communication between LEO satellites and ground stations is in a complex channel environment, so it is a critical issue for the realization of that direct spread spectrum communication system for fast synchronization. Based on the characteristics of the LEO satellite channel, the paper proposes a selected automatic censoring excluding average (SACEA) method based on the automatic censoring cell average...
This paper addresses two majors problems in today's wireless network using MIMO-OFDM. In fact, the performances of such a network depend on the interference management and on the equalization. These two problems are closely linked to channel estimation algorithms. In this paper, we propose a resource sharing scenario combined with a blind channel estimation algorithm based on fourth order statistics...
Superposed multicarrier transmission scheme is known to improve frequency utilization efficiency when several wireless systems share the same spectrum. To suppress the effect of interference, forward error correction (FEC) metric masking is proposed. In the technique, log-likelihood ratio (LLR) that corresponds to superposed band is set to zero, because received bits that correspond to superposed...
In this paper, a unified framework, denoted as generalized nonlinear detection (GND), is developed to encompass existing nonlinear detection technologies as well as further optimize the performance of nonlinear detection for noncoherent impulse radio (IR) ultra-wideband (UWB) receivers. Computer simulations show that independent of absence or presence of narrowband interferences (NBIs), the GND-based...
In this paper, we investigate robust precoding for two-way relay cognitive networks consisting of a pair of cognitive transceiver users equipped with Multiple Input Multiple Output (MIMO) antenna communicating with each other through a common multi-antenna relay and sharing the same spectrum with primary users (PU). The uncertainty set in this CSI model is defined as Norm Bounded Error (NBE) model...
Due to large numbers of interferers, in-band interference is a bottleneck that future wireless heterogeneous networks have to deal with. Recent advances in information theory have shown that interference does not have to be avoided or strongly limited, so that reliable transmissions can occur. In this paper, we propose a novel Radio Resource Management (RRM) approach, capable to exploit those recent...
Multicarrier transmissions are classically based on undercomplete or exact Weyl-Heisenberg Riesz (biorthogonal or orthogonal) bases implemented thanks to oversampled filter-banks. This can be seen as a transmission below the Nyquist rate. However, when overcomplete Weyl-Heisenberg frames are used, we obtain a “faster-than-Nyquist” (FTN) system and it is theoretically impossible to recover exactly...
In this paper, a network consisting of several partially connected subnetworks where each subnetwork includes one relay is considered. “Partially connected” means that not all nodes are connected to all relays. Some nodes may be connected to multiple relays. The entire bidirectional pair-wise communication between the nodes takes place via the intermediate half-duplex amplify-and-forward relays, considering...
The simple scheme of treating interference as noise (TIN) is studied in this paper for the 3 × 2 X channel. A new sum-capacity upper bound is derived. This upper bound is transformed into a generalized degrees-of-freedom (GDoF) upper bound, and is shown to coincide with the achievable GDoF of a scheme that combines TDMA and TIN for some conditions on the channel parameters. These conditions specify...
We consider an additive multiple-access channel where single-user decoding is performed at the receiver and study the Shannon capacity when the interference is modeled as impulsive alpha-stable and the additive noise as Gaussian distributed. We investigate scenarios whereby the input is possibly non-linearly distorted, and consider generic cost functions on the input. We prove that the optimal input...
Automatic Gain Control (AGC) system performance generally depends on the ability to accurately estimate receive signal power. The initial gain setting may be set high to ensure that low power signals can be detected. As the Variable Gain Amplifier (VGA) resides before the Analog to Digital Converter (ADC), there is a potential for heavy saturation at the output of the ADC, where this estimation is...
Inter-cell interference in LTE-Advanced can be mitigated using coordinated multi-point (CoMP) techniques with joint transmission of user data. However, this requires tight coordination of the eNodeBs, using the X2 interface. In this paper we use discrete-event simulation to evaluate the latency requirements for the X2 interface and investigate the consequences of a constrained backhaul. Our simulation...
Relaxed synchronization is considered essential for future generations of wireless networks in order to reduce signaling overhead. Filterbank Multicarrier (FBMC) modulation receivers may be implemented in the frequency domain as synchronization and equalization may be performed jointly. Furthermore it is demonstrated that FBMC exhibits better capacity than OFDM when frequency division multiple access...
The ever increasing dynamic range requirement for the RX path and maximum transmission power requirement for the TX path add difficulty in the Bluetooth transceiver design. The tradeoff between noise and linearity performance is carefully examined to meet the RX dynamic range requirement. RX anti-interference performance is improved by careful system level planning. TX non-idealities are addressed...
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....
Coordinated Multipoint (CoMP) transmission provides high theoretic gains in spectral efficiency, in particular with coherent linear Joint Transmission (JT) to multiple users. However, this requires high backhaul capacity. If the backhaul requirement cannot be met by the system, then CoMP gains decrease as the linear precoder matrix must be adjusted to include zeros. To minimize the loss of CoMP gains,...
In this paper the robustness of a four-element compact navigation antenna array against continuous-wave interferers is investigated. The compact antenna array is integrated with an analog decoupling and matching network to mitigate the mutual coupling between the antenna elements and restore efficient diversity gain. It is observed that the network improves the equivalent carrier-to-interference-plus-noise...
An overview of the challenges related to spectrum sharing between radar and communication systems is provided and some potential ways to address them are indicated.
Maximum common sub-graph isomorphism (MCS) is a famous NP-hard problem in graph processing. The problem has found application in many areas where the similarity of graphs is important, for example in scene matching, video indexing, chemical similarity and shape analysis. In this paper, a novel algorithm Qwalk is proposed for approximate MCS, utilizing the discrete-time quantum walk. Based on the new...
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