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In this work the performance of the Sucessive Interference Cancelation (SIC) architecture combined with Matching Pursuit (SIC/MP) and Least Squares (SIC/LS) algorithms is statistically analyzed when they are used to mitigate multipath effect in an Acoustic Local Positioning System (ALPS). The experiments are carried out with sets of two hundred real signals acquired in positions where there exists...
The algorithm of reception signals with orthogonal frequency multiplexing (OFDM) in channels with dispersion is considered. The offered algorithm is based on processing "in general" on an interval of dispersion of sequence of counting of the bending-around symbol OFDM for the purpose receiving estimates of maximum likelihood of this sequence with the subsequent formation solutions of rather...
During the reconstruction process, scatter correction and normalization needs to be applied to correct raw PET data. Normalization corrects for all the variations between the detector responses and typically consists of various components each representing specific physical effect. Only one set of normalization components is typically estimated for the clinical energy window. However, some of the...
Combating interference is an important yet challenging issue for multiuser communications especially in the harsh underwater acoustic environment. In this paper, a novel Angle-Of-Departure (AOD)-based technique is proposed, which accounts for the inherent position uncertainty of underwater propeller-driven Autonomous Underwater Vehicles (AUVs) or buoyancy-driven gliders. A new probabilistic Space...
Cross-technology interference on the license-free ISM bands has a major negative effect on the performance of Wireless Sensor Networks (WSNs). Channel hopping has been adopted in the Time-Slotted Channel Hopping (TSCH) mode of IEEE 802.15.4e to eliminate blocking of wireless links caused by external interference on some frequency channels. This paper proposes an Enhanced version of the TSCH protocol...
A method of passively estimating the resource block (RB) utilization rate of a serving cell according to radio-quality information measured by a user terminal is proposed. The estimated RB utilization rate can be regarded as the traffic load on the base station. The contribution of this paper is twofold: first, a method for passively estimating a traffic load on a base station via a user terminal...
In this paper, we study the impact of clock timing mismatch of analog-to-digital converter in a receiver that employs quadrature bandpass sampling of the radio frequency (RF) signal. It is shown that the clock timing mismatch introduces not only symbol timing offset but also image interference, that is, the interference between in-phase and quadrature signals. Then, a mismatch compensation scheme...
This paper addresses the problem of estimating the Multi-User Multiple Input Multiple Output (MU-MIMO) Channel Quality Indicator (CQI) from the reported Single-User MIMO rank-1 CQI. A hybrid MU-MIMO CQI estimation algorithm is proposed. Proposed algorithm applies a fixed back off offset to compensate the power sharing among co-scheduled users and a dynamic offset for Multi-User (MU) interference....
This paper reports our recent result in designing a function for autonomous APs to estimate throughput and delay of its clients in 2.4GHz WiFi channels to support those APs' dynamic channel selection. Our function takes as inputs the traffic volume and strength of signals emitted from nearby interference APs as well as the target AP's traffic volume. By this function, the target AP can estimate throughput...
In this work, the analysis on the design and implementation of dense wireless sensor networks is presented, by performing deterministic wireless channel analysis, providing assessment on topological and morphological impact of complex urban environments in the operation of the employed wireless sensor networks, within WLAN/WPAN standards. The proposed methodology, combining initial radioplanning estimations...
This paper presents a weighted least squares algorithm for passive localization using Time Difference of Arrival in multipath scenarios. The algorithm is based on the direct or one-step approach for position estimation using distributed sensors and requires no knowledge about the number of received multipaths, the transmitted signal or the transmit time. Delayed signal paths arriving due to multipath...
Recently, there has been an increasing interest in GNSS-based safety and liability applications. These applications, which are often associated to urban environments or in general to vehicular applications, have very stringent requirements in terms of accuracy, continuity and integrity of the provided position solution. In this paper, we present simple quickest threat detectors for being used in low-cost...
This paper analyzes the bit error rate (BER) performance of grouped frequency division multiple access (GFDMA) using a tool known as finite length analytical tool (FLAT). We derive the equations of the FLAT method including the variance of the equalizer output signal for different iterations. We use this value to calculate the BER of the equalizer output when a specific set of sub-carriers are assigned...
In frequency-hopping systems, the multiple-access interference (MAI) occurs when more than one user appear on the same frequency at the same time. In this paper, we address the multi-user detection (MUD) problem for slow frequencyhopping (SFH) system with binary phase shift keying (BPSK). We first built a MAI model taking the hopping patterns and the phase offset into account, whereby the MAI is considered...
This paper proposes a model for the management of virtual radio resources, considering different assumptions on terminals' Signal-to-Interference- plus-Noise Ratio. The model has two main components: estimation and allocation of the available resources. In the former, a technique for obtaining probability functions for the network throughput based on the available radio resources is introduced; in...
The paper presents an improvement of the long term evolution (LTE) link adaptation for voice over LTE (VoLTE). The underlying problem is associated with the speech frame structure of VoLTE, where the transmissions are typically scheduled every 40 ms, provided that discontinuous reception (DRX) is on. The channel estimates of each user are hence outdated each time a new uplink scheduling decision is...
Pilot reuse (PR) in each cell has been proposed to reduce the pilot overhead and improve the throughput of massive multiple-input multiple-output systems. Since PR can introduce interference into channel estimation, several pilot scheduling schemes have been developed to alleviate this problem. However, current schemes have high computational complexity. In this paper, we try to design a low-complexity...
Radiated interference environments can significantly degrade the performance of the digital communication systems that are widely used today. Problems from such intersystem interference might need to be analyzed beforehand or as problems occur. Another application where such analysis is of interest is in systems using dynamic allocation of spectrum, where it serves as basis for spectrum allocation...
The advancements in wireless mesh networks (WMN), and the surge in multi-radio multi-channel (MRMC) WMN deployments have spawned a multitude of network performance issues. These issues are intricately linked to the adverse impact of endemic interference. Thus, interference mitigation is a primary design objective in WMNs. Interference alleviation is often effected through efficient channel allocation...
This paper is focused on the issue of complexity and low accuracy of downlink (DL) power control in dense heterogeneous network. A novel power control algorithm based on the interference statistic properties that is accurate and results in easy-to-evaluate interference is proposed. Compared to the recent work on DL power control using complex iterations to manege interference, the proposed algorithm...
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