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Device-to-Device (D2D) communications allow devices to communicate directly without going through infrastructure. It is considered a promising solution to improve communication performance and network capacity of LTE-Advanced (LTE-A) system. However, in D2D networks, the co-existence of multiple D2D User Equipments (UEs) is a challenging issue due to the proximity interference caused by collisions,...
L-band digital aeronautical communications system type 1 (LDACS1) is a multicarrier transmission system proposed to cope with the increasingly growing demand in the aeronautical communications. LDACS1 offers the possibility to operate as an inlay system in the frequency "gaps" between adjacent distance measuring equipment (DME) channels. Therefore, DME signals are interference signals from...
In order to evaluate the immunity of DVB signal to external interferer we made some measurements and comparisons between DVB-T signal and DVB-C signal of 8 MHz bandwidth subject to a FM interferer.
The IEEE 802.11p standard will in the next years be introduced for vehicle-to-vehicle and vehicle-to-infrastructure (V2X) communication. Some of the services in this standard are dedicated to active road safety applications and can therefore be sensitive to radio interference. Since the system is based on Automatic Repeat Request (ARQ) and Carrier Sense Multiple Access (CSMA), interference problems...
We review the modeling of nonlinear interference noise (NLIN) in fiber communications, focusing on the accurate extraction of the NLIN variance, the dependence on modulation format, the role of nonlinear phase-noise and the existence of temporal correlations. We show ways in which temporal correlations can be exploited for reducing the impact of NLIN, and discuss the prospects of this procedure in...
Polyphase magnitude modulation (MM) has been shown to be a robust and effortless mean to improve the efficiency of a transmitter's high power amplifier (HPA), due to the real-time reduction of the peak to average power ratio (PAPR). MM's technique flexibility allows us to include the MM system on any existing single-carrier (SC) based transmission system with clear benefits on the achieved bit error...
Adaptive Modulation and Coding (AMC) in LTE networks is commonly employed to improve system throughput by ensuring more reliable transmissions. Most of existing AMC methods select the modulation and coding scheme (MCS) using pre-computed mappings between MCS indexes and channel quality indicator (CQI) feedbacks that are periodically sent by the receivers. However, the effectiveness of this approach...
In this paper, we derive an effective SINR mapping algorithm based on Mutual Information (MI) Effective SINR Metric (ESM) model for 256QAM modulation system. Since recently 256QAM modulation is proposed in 3GPP LTE-A Rel.12 and IEEE 802.11ac standard, the design of Link-to-System (L2S) interface for 256QAM needs to be considered. Based on the Log Likelihood Ratio (LLR) receiver model, we derive the...
Time modulation is explored as a tool for inexpensive sidelobe blanking in a digital beamformer. Rapid switching of the steering coefficients encodes acquisition and sidelobe suppression beams within a single output during beamforming so that they are separable by a synchronized decoder. The computational cost is the same as traditional beamforming, making this method advantageous versus other sidelobe...
This paper studies the impact of imperfect channel state information (CSI) due to limited feedback link on the performance of multi-user MIMO system using filter bank based multicarrier (FBMC) modulation. The system is composed of a transmitter performing Zero Forcing (ZF) precoding and single antenna receivers applying decoding techniques. Simulation-based results show that except when the number...
The focus of this work is put on a cognitive network wherein the secondary users (SUs), based on bit-interleaved-coded orthogonal frequency division multiplexing, share the same band of primary users (PUs). In this context, we develop a distributed power allocation (PA) strategy which minimizes the coded packet error rate (PER) of the noncooperative SU links under the constraint of satisfying the...
Doppler-free spectroscopy of gases in hollow-core fiber (HCF) -based cells can be used for realizing new compact, robust and portable frequency standards. In this summary a method for cancelling interferences resulting from splices between standard telecom fiber and HCF using two piezoelectric stack actuators is presented. Both HCF and mirror-side standard fiber are modulated by stretching. The performance...
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 addresses the margin adaptive problem for the filter bank multicarrier (FBMC) modulation based on the offset QAM (OQAM), referred to as FBMC/OQAM. The analysis conducted in this paper reveals that due to the specific FBMC/OQAM transmission format the system has to deal with inter-user, inter-symbol and inter-carrier interference to solve the resource allocation problem. To manage the interference,...
In this paper, we propose a coordination based resource management (CBRM) scheme with quality-of-service (QoS) provisioning for multicell OFDMA downlink systems. The proposed CBRM scheme cooperates with the multiple point deployment and the enhanced fractional frequency reuse (FFR). To solve the intra-cell interference brought by multiple point deployment, the CBRM scheme adopts a utility function...
The Binary Offset Carrier (BOC) modulation has been selected by the four most influential Global Navigation Satellite Systems (GNSS) and several other regional ranging systems. Although the Autocorrelation Function (ACF) of BOC has sharper main peak and better multipath mitigation performance than BPSK, its multiple side peaks cause ambiguity in signal acquisition and tracking. In this paper, we present...
Spectrally Efficient Frequency Division Multiplexing (SEFDM) is a non-orthogonal multi-carrier communication technique that can pack more sub-carriers than Orthogonal Frequency Division Multiplexing (OFDM) for a given bandwidth. In this paper, we propose a hybrid soft Iterative Detection (ID) together with Fixed Sphere Decoding (FSD) for QAM modulation schemes from 4QAM to 16QAM. In terms of 4QAM,...
It is widely accepted that SC-FDE (Single Carrier with Frequency Domain Equalization) schemes are preferable for the uplink of broadband wireless systems since these signals have lower PAPR (Peak to Average Power Ratio) than OFDM (Orthogonal Frequency Division Multiplexing) signals. However, when we want to employ power-efficient grossly nonlinear amplifiers, as in satellite communications, the SC...
We review the modelling of nonlinear interference in wavelength division multiplexed (WDM) fibre-optic systems. In particular, we focus on the analysis of inter-channel nonlinear interference noise, to which we refer as NLIN. We discuss the derivation of the variance and elaborate on the properties of NLIN in terms of its temporal correlations, the extent to which it manifests itself as nonlinear...
In this work, we propose a novel interference alignment (IA) scheme for two-cell MIMO downlink channels. With this scheme the interference will be aligned to the same directions with the desired signals when the transmitters are sending out the same symbols, otherwise, the interference will be aligned to the orthogonal directions of the desired signals as the traditional IA scheme does. As a result,...
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