Non-orthogonal multiple access for terahertz communication networks

Terahertz communications is one of the promising technologies for the future mobile communication networks. Due to the ever increasing need for high-speed data transfer, higher bandwidths are required. As a solution, higher frequencies in the spectrum may be considered for future networks. In this paper, Terahertz band is selected since the latest technological advances make it possible to deploy mobile networks in this high-frequency band. To support higher bandwidth with an advanced multiple access method, non-orthogonal multiple access (NOMA) is implemented in this paper. Different from orthogonal multiple access (OMA), NOMA makes it possible for users to share the same frequency and time resources simultaneously, therefore increases the spectral efficiency. To measure the efficiency of the implemented methods, computer simulations are used and results are obtained for different scenarios. In the simulation results, it is shown that NOMA provides higher average data rates for these scenarios where users are located on variety of distances far from the Terahertz access point. As a result, this work shows NOMA for Terahertz communication networks is a promising method for future communication networks

Busy tone implementation for coexistence of IEEE 802.22 and 802.11af systems

Bu bildiride, IEEE 802.22 ve IEEE 802.lIaf sistemlerinin TV beyaz boşlugunda birlikte varolabilmeleri için meşgul ton tabanlı yeni bir algoritma önerilmiştir. Önceki meşgul ton tabanlı çalışmalardan farklı olarak 802.11af erişim noktasmm meşgul tonu dinlemesinin yanı Sıra, erişim noktasınan bağlı kullanıcılar da meşgul ton sinyali dinlemekte ve bu sinyali duyduklarmda erişim noktasına iletmektedirler. Böylelikle 802.22 sistemlerine yapılan girişim azaltılmaktadır. Bu çalışmada standartlara uygun iletişim parametreleri ve kanal modelleri dikkate almaları ve önerilen sistemin iyileştirme performansı girişim yapan paket oranı cinsinden değişik duyma bölgeleri için elde edilmiştir.In this paper, a new algorithm based on busy tone approach has been proposed for the coexistence of IEEE 802.22 and IEEE 802.11af systems in TV white space. Different from the earlier study, in addition to 802.11af access points listening to the busy tone signal, their clients also listen to the busy tone and let the access points know once they hear it. Accordingly, interference caused to 802.22 systems has been reduced. This study quantifies the improved system performance in terms of interfering packet rate for different hearing regions considering the communication parameters and channel models adapted for the standards. © 2015 IEEE

A new approach for coexistence of IEEE 802.11af and IEEE 802.22 systems

Bu bildiride, birden fazla teknik kullanılarak IEEE 802.11af ve IEEE 802.22 kablosuz sistemlerinin TV beyaz bo¸slugunda birlikte varolabilmeleri için algoritmalar geli¸stirilmi¸stir. ˘Me¸sgul tonu, güç kontrolü ve çok sekmeli haberle¸sme teknikleri kullanılarak daha önce yapılan çalı¸smalar temelinde iyile¸stirmeler yapılmı¸stır. IEEE 802.22 sistemlerinin korunumu birinci planda yer alırken, aynı zamanda IEEE 802.11af sistemlerininde haberle¸smeye devam etmesi saglanmı¸stır. Standartlara uygun ˘haberle¸sme parametreleri ve kanal modelleri kullanılan bu çalı¸smada, her iki sistemin de paket giri¸sim oranları ve ba¸sarılı paket oranları farklı senaryolar için incelenmi¸s ve iyile¸stirilmi¸s sonuçlar ortaya konulmu¸stur.In this paper, various algorithms are proposed to help IEEE 802.11af and IEEE 802.22 wireless systems to coexist in TV white space by considering multiple techniques. By using busy tone, power control and multihop communication techniques, improvements have been made compared to prior approaches. With this approach, while IEEE 802.22 systems are protected from intra-network interference, IEEE 802.11af systems are still able to continue transmitting packets. Considering the communication parameters and channel models compliant for the standards, IEEE 802.11af and IEEE 802.22 system performances are investigated in terms of interfering packet rate and successful packet transmission rate for different scenarios and the improved results are presented.IEEEHuaweiAselsanNETA

Busy tone based coexistence algorithm for WRAN and WLAN systems in TV white space

WOS: 000441140700015TV White Space (TVWS) refers to frequency band reserved only for licensed terrestrial TV broadcasting and is opened to unlicensed use under regulatory conditions. While regulations protect licensed systems from interference, interference among unlicensed systems is left mainly to manufacturers. Consequently, there is a need to develop new coexistence approaches between TVWS networks. Busy tone broadcasting is a coexistence method, which can be used by TVWS networks to announce the selected frequency band is occupied. In this paper, a busy tone based coexistence algorithm is proposed for IEEE 802.11af and IEEE 802.22 networks and analyzed by considering different client distributions experiencing log-normal shadowing, where the exact interfering packet rate and successful packet transmission rate expressions are obtained and validated by simulations for different scenarios. The results show that with the proposed coexistence approach, a WLAN can reliably detect the busy tone signal to change its frequency band and can reduce interference to WRAN. Even if there is no available frequency band for the WLAN, the WRAN still maintains its enhanced successful packet transmission performance. The deployment of the proposed algorithm is important for successful coexistence between cognitive wireless networks, where interference is not regulated, such as in TVWS bands.Turk Telekom; Argela under the TT Collaborative Research Awards programme; TUBITAK programme [2232]This research was supported by Turk Telekom and Argela under the TT Collaborative Research Awards programme. The work of Tuncer Baykas is supported by TUBITAK 2232 programme

Analysis of extended busy tone performance for coexistence between WRAN and WLAN TVWS networks

TV White Spaces indicate spectrum bands, which were reserved for licensed terrestrial TV broadcasting and opened to unlicensed use under regulatory conditions. One important regulation which is common in all regulatory domains is no harmful interference is created to licensed devices. On the other hand, interference between unlicensed devices is not regulated. As a result system designers developed new methods to improve coexistence between TVWS networks. Extended busy tone, one of such methods, is designed for coexistence between wireless regional area and wireless local area networks based on IEEE 802.22 and 802.11af standards, respectively. In this paper we analyse the performance of extended busy tone at different range conditions and verify via simulations under realistic conditions. Our results indicate that the method can reduce interference considerably at intermediate distances and enable networks to operate without a significant reduction in throughput. © 2015 IEEE

A novel indoor channel model for tvws communications based on measurements

In this paper, we present an indoor measurement campaign for TV white space bands inside a university building. The measurement results are compared with different indoor propagation models in the literature. We observed large estimation errors for the total path loss value from all existing models. Consequently, we are proposing a new indoor propagation model for TVWS frequencies, which concatenates the effects of frequency dependent path loss with penetration losses due to walls and windows. Performance comparison with existing models show that the proposed model achieves superior performance compared to existing models in terms of Root-Mean-Squared Error (RMSE)

The Effect of Channel Models on Compressed Sensing Based UWB Channel Estimation

Ultra-wideband (UWB) multipath channels are assumed to have a sparse structure as the received consecutive pulses arrive with a considerable time delay and can be resolved individually at the receiver. Due to this sparse structure, there has been a significant amount of interest in applying the compressive sensing (CS) theory to UWB channel estimation. There are various implementations of the CS theory for the UWB channel estimation based on the assumption that the UWB channels are sparse. However, the sparsity of a UWB channel mainly depends on the channel environment. Motivated by this, in this study we investigate the effect of UWB channel environments on the CS based UWB channel estimation. Particularly, we consider the standardized IEEE 802.15.4a UWB channel models and study the channel estimation performance from a practical implementation point of view. The study shows that while UWB channel models for residential environments (e. g., CM1 and CM2) exhibit a sparse structure yielding a reasonable channel estimation performance, channel models for industrial environments (e. g., CM8) may not be treated as having a sparse structure due to multipaths arriving densely. The results of this study are important as it determines the suitability of different channel models to be used with the CS theory

Hibrit MEMS-tabanlı moleküler haberleşme sistemi

In this paper, we consider a molecular communication link integrated in a micro-electro mechanical system (MEMS) based environment. We apply acoustic tweezing techniques to the molecular communication system to increase communication reliability. We use finite element methods to simulate this hybrid system. By deriving the symbol error rate as the performance metric, we show that the proposed system facilitates reliable communication in the presence of fluid flow and its performance is robust against external factors, such as temperature.Bu bildiride, mikro elektro mekanik sistem (MEMS) tabanlı bir ortama entegre edilmiş bir moleküler iletişim bağlantısını ele alıyoruz. İletişim güvenilirliğini artırmak için moleküler iletişim sistemine akustik cımbızlama teknikleri uyguluyoruz. Bu hibrit sistemi simüle etmek için sonlu eleman metotları kullanıyoruz. Performans ölçütü olarak sembol hata oranını tüketerek önerilen sistemin sıvı akışının varlığında güvenilir iletişimi kolaylaştırdığını ve performansının sıcaklık gibi dış etkenlere karşı dayanıklı olduğunu gösteriyoruz.27th Signal Processing and Communications Applications Conference, SIU 2019 April 2019, Article number 8806346 27th Signal Processing and Communications Applications Conference, SIU 2019; Sivas; Turkey; 24 April 2019 through 26 April 2019; Category numberCFP19559-ART; Code 151073IEEE Turkey SectTurkcellTürkhavacılık UzaysanayiiTuritak BilgemGebze Teknik UniversitySAPDetaysoftNETASHavelsa

Busy tone based power control for coordination of IEEE 802.11af and 802.22 system

Bu bildiride, IEEE 802.22 ve IEEE 802.11af kablosuz sistemlerinin TV beyaz boşluğunda uyumlu çalışabilmeleri için meşgul ton tabanlı yeni bir güç kontrol algoritması önerilmiştir. Daha önceki meşgul ton tabanlı çalışmalardan farklı olarak, 802.11af erişim noktası ve erişim noktasına bağlı kullanıcılar meşgul ton sinyalini algıladıktan sonra haberleşme güçlerini konum bilgilerine göre ayarlamakta ve gerekiyorsa iki hop üzerinden haberleşmektedirler. Böylelikle 802.22 sistemlerine yapılan girişim azaltılırken, 802.11af sistemlerinin haberleşmesi de mümkün kılınmaktadır. Bu çalışmada standartlara uygun haberleşme parametreleri ve kanal modelleri dikkate alınarak, 802.11af ve 802.22 sistemlerinin performansları paket girişim oranı ve başarılı paket oranı türlerinden farklı senaryolar altında incelenmiştir.In this paper, a new power control algorithm based on busy tone approach has been proposed for the coordination of IEEE 802.22 and IEEE 802.11af systems in TV white space. Different from the earlier studies, in addition to both 802.11af access point and clients listening to the busy tone, they also adjust their communication power according to the location information and use hopping for communication, if needed. Acccordingly, interference caused to 802.22 systems has been reduced while the 802.11af systems are still able to communicate. This study quantifies the 802.11af and 802.22 system performances in terms of interfering packet rate and succesful packet transmission rate for different scenarios considering the communication parameters and channel models adapted for the standards