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Lower time-frequency resolution is caused by Smoothed pseudo Wigner-Ville distribution (SPWVD) in suppressing cross-terms interference, which limits its application in the processing of the non-stationary vibration signals. This paper proposes a novel fractional-order smoothed pseudo Wigner-Ville distribution (FrSPWVD) to solve the above problem. The details about step of the calculation are as follows:...
Usually, the stray signals from antenna test environment and compact antenna test range (CATR) system may cause errors in the measured patterns. In order to improve the measurement accuracy of a specific antenna test system, the techniques about antenna pattern correction for mitigating the effects of these stray signals are required. In this paper, a two-unit virtual array method and its extended...
How to associate a femto user (FU) to an appropriate femto base station (FBS) to avoid interference and maximize the achievable data rate (ADR) of FUs has attracted a lot of attention in femtocell networks. The evidence provided in this paper proves it to be an NP-complete problem. To maximize the ADR of the FUs, the methods for assigning FUs to neighboring FBSs are examined to determine the required...
The multiband orthogonal frequency division multiplexing ultra-wideband (MB-OFDM UWB) system suffered from the narrowband interference (NBI) due to the presence of coexistence communication system, such as worldwide interoperability for microwave access (WiMAX). If we deal with the NBI before the receiver, the performance of MB-OFDM UWB system can be significantly improved. The NBI cancellation algorithms...
Orthogonal frequency division multiple access (OFDMA), which is known as one of the most promising physical techniques for advanced wireless communications system, generally has a guard interval (GI) to mitigate the inter-symbol interference (ISI) and inter-carrier interference (ICI) caused by delay paths. However, the intra-cell interference (ISI and ICI) may be severe, when GI becomes insufficient...
We address the problem of frequency reuse schemes in the downlink of the fixed two-hop orthogonal frequency division multiple access (OFDMA) cellular relaying networks. There has been little work on specific frequency reuse schemes for this system in the literatures, although this is the key element for realizing the potential capacity and coverage increase offered by the relay. Therefore, we propose...
Two points need to be considered on power loading policy of cognitive radio (CR) systems. The first is to maximize the channel capacity over the given frequency band, which is detected usable for CR systems. The second is the out-of-band interference suppression of the CR systems. In the paper based on the mathematical expression of the interference power caused by MB-OFDM based CR systems, the relationship...
This paper addresses aspects of routing strategy of a cellular network enhanced with two-hop fixed relay nodes. The routing strategy for each user is important design parameter because the terminal is energy-limited. To enhance the radio resource utility, a utility maximization framework via pricing is adopted for multi-cell distributed power allocation. Under the optimization physical layer transmission...
Cognitive radio systems offer the opportunity to improve spectrum utilization while avoiding the interference to primary users. Secondary users must be aware of interference caused to primary users. Therefore cognitive radio network should take primary users into account and control their transmission power. This paper focuses on the coverage analysis of cognitive radio network and finds its coverage...
A mathematical expression of side-band interferences caused by sub-carriers of multi-band (MB)-OFDM UWB based cognitive radio is derived. Based on this expression, the constraint relationship among transmitted symbols, which is satisfied to suppress the interferences, is obtained. Combined with this constraint, the design process of a type of LDPC-like modulation scheme is described. With modulation...
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