Extensionless Adaptive Transmitter and Receiver Windowing of Beyond 5G Frames

Newer cellular communication generations are planned to allow asynchronous transmission of multiple numerologies (waveforms with different parameters) in adjacent bands, creating unavoidable adjacent channel interference. Most prior work on windowing assume additional extensions reserved for windowing, which does not comply with standards. Whether windowing should be applied at the transmitter or the receiver was not questioned. In this work, we propose two independent algorithms that are implemented at the transmitter and receiver, respectively. These algorithms estimate the transmitter and receiver windowing duration of each resource element (RE) with an aim to improve fair proportional network throughput. While doing so, we solely utilize the available extension that was defined in the standard and present standard-compliant algorithms that also do not require any modifications on the counterparts or control signaling. Furthermore, computationally efficient techniques to apply per-RE transmitter and receiver windowing to signals synthesized and analyzed using conventional cyclic prefix orthogonal frequency division multiplexing are derived and their computational complexities are analyzed. The spectrotemporal relations between optimum window durations at either side, as well as functions of the excess signal to noise ratios, the subcarrier spacings and the throughput gains provided over previous similar techniques are numerically verified.Comment: 15 pages, 2 algorithms, 3 tables, 11 figures (1 of which includes 3 subfigures) and 3 author biographies. Final version accepted for publication in IEEE Transactions on Vehicular Technolog

Performance Analysis of Transmitter Identification Based on I/Q Imbalance Estimation

Performance of a transmitter identification method based on I/Q imbalance estimation is analyzed for different modulation types in this work. This analysis is considered on the basis of the constellation structure of proper and improper modulation signals. The effect of impropriety of complex signals on the features obtained from I/Q imbalance is analyzed. Simulation results show that transmitters can be identified with a high accuracy for proper communication signals even at low SNR, whereas the identification performance degrades for improper communications signals, especially at low SNR. © 2019 IEEE

Sequential Transient Detection for RF Fingerprinting

In this paper, a sequential transient detection method for radio frequency (RF) fingerprinting used in the identification of wireless devices is proposed. To the best knowledge of the authors, sequential detection of transient signals for RF fingerprinting has not been considered in the literature. The proposed method is based on an approximate implementation of the generalized likelihood ratio algorithm. The method can be implemented online in a recursive manner with low computational and memory requirements. The transients of wireless transmitters are detected by using the likelihood ratio of the observations without the requirement of any a priori knowledge about the transmitted signals. The performance of the method was evaluated using experimental data collected from 16 Wi-Fi transmitters and compared to those of two existing methods. The experimental test results showed that the proposed method can be used to detect the transient signals with a low detection delay. Our proposed method estimates transient starting points 20-times faster compared to an existing robust method, as well as providing a classification performance of a mean accuracy close to 95%

Reducing Precoder/Channel Mismatch and Enhancing Secrecy in Practical MIMO Systems Using Artificial Signals

Practical multiple-input-multiple-output (MIMO) systems depend on a predefined set of precoders to provide spatial multiplexing gain. This limitation on the flexibility of the precoders affects the overall performance. Here, we propose a transmission scheme that can reduce the effect of mismatch between users' channels and precoders. The scheme uses the channel knowledge to generate an artificial signal, which realigns the predefined precoder to the actual channel. Moreover, the scheme can provide an additional level of secrecy for the communication link. The performance of the proposed scheme is evaluated using bit-error rate (BER), error vector magnitude (EVM), and secrecy capacity. The results show a significant improvement for the legitimate user, along with a degradation for the eavesdropper.Comment: 4 pages, 5 figures. Accepted for publication in IEEE Communications Letter

Effect of climate factors on wood veneers exposed to outdoor conditions in black sea region

In this study, 2×100×200 mm wood veneers obtained from Scots pine (Pinus sylvestris L.), European black pine (Pinus nigra Arn.) and beech (Fagus orientalis L.) wood were exposed to outdoor climate conditions at three different cities (Trabzon, Artvin, and Kastamonu) of Black Sea region in Turkey for totally 4 months from May to August, 2012. The aim of this study was to investigate the effect of climate factors on the changes occurred on different types of wood veneers that were subjected to outdoor weathering conditions. Weight losses, surface roughness, and color changes occurred on veneers were determined during natural weathering. Additionally, the weathering map of wood in three cities studied was calculated using Scheffer Climate Index (SCI) in order to characterize the potential decay risk of wood materials. Accordingly, at the end of the 4 months, the highest weight losses for Scots pine veneers were obtained from the weathering conditions in Artvin while the lowest weight losses were obtained in Kastamonu. For European black pine and beech veneers, the highest weight losses were obtained from Trabzon, and the lowest weight losses were obtained from Kastamonu. The highest color change value (?E*) obtained from Trabzon and Artvin, the lowest ?E* obtained from Kastamonu for Scots pine veneers. For European black pine veneers, the highest ?E* obtained from Trabzon while the lowest ?E* was obtained from Artvin and Kastamonu. For beech veneers, the highest ?E* was obtained from Artvin, the lowest ?E* obtained from Kastamonu. For all veneers, the lowest surface roughness was determined in Trabzon. The highest surface roughness was obtained in Artvin for Scots pine and it was obtained in Kastamonu for European black pine and beech. Based on the result of SCI analysis, the most risky city for decay potential of fungi was Trabzon, then Artvin and Kastamonu, respectively

Louis Sullivan'ın mimarlığı'ndaki egzotizm'in kaynakları : ilkel, oryantal, doğal

The aim of this study is to demonstrate the idea of Exoticism and its effect on nineteenth century architectural tendencies and especially on the philosophy and the works of Louis Sullivan (1856-1924). The study begins with an elucidation of the concept أexoticism.ؤ After the thoughts of a group of nineteenth century European intellectuals are discussed, the philosophy of Sullivan is analyzed. Following chapters are dedicated to the works of Sullivan. Exotic world was the source of a stimulating discourse for the nineteenth century intellectuals. American architect Sullivan also found inspiration in it. In the development of his philosophy, Sullivan concentrated on the idea of أintegrity of man and nature,ؤ and he realized that integrity was present in the art of primitive and especially Oriental cultures. His universal formula, أform follows function,ؤ was based on the idea that the primitive man did not put a barrier between himself and nature; hence every artwork created by him was a process of transformation of natural forms. Sullivan modeled his designs upon nature and in this way attempted to reproduce this creative process. This study interprets Sullivan̕s philosophy and works and also discusses their likely contribution to the work of the contemporary architect.M.Arch. - Master of Architectur

Adaptive windowing of insufficient CP for joint minimization of ISI and ACI beyond 5G

Using minimum, even insufficient guards are proposed to achieve the spectral efficiency and latency requirements of cellular communication systems beyond 5G. This leads to interference in both time and frequency domains. In this paper, a partial-non-orthogonal multiple accessing scenario in which the desired user is experiencing both intersymbol interference (ISI) due to insufficient cyclic prefix (CP) and adjacent channel interference (ACI) caused by asynchronous transmitters using non-orthogonal numerologies in adjacent bands is investigated. ISI and ACI depend on the power offset between desired and interfering users, the instantaneous channel impulse responses of interfering users and transmitter and receiver window functions. Therefore, joint and adaptive utilization of CP requires real-time calculation of ISI and ACI. Analytical expressions for expected ISI and ACI at each subcarrier of the desired user are derived to minimize their combination. Accordingly, an adaptive algorithm consisting of windowing each subcarrier at the receiver with window length that minimizes the combined interference at that subcarrier by optimally exchanging ISI and ACI is proposed. Interference reduction performances of current, outdated and average optimal window length raised cosine receiver windows are assessed and compared to fixed and no receiver windowing. Windowing reduces interference even when CP is shorter than the channel if window length is determined using the proposed design guidelines.Institute of Electrical and Electronics Engineers Inc.IEEE Communications Societ