Outage Performance of Bidirectional Full-Duplex Amplify-and-Forward Relay Network with Transmit Antenna Selection and Maximal Ratio Combining, Journal of Telecommunications and Information Technology, 2018, nr 1

In this paper, a bidirectional full-duplex amplify- and-forward (AF) relay network with multiple antennas at source nodes is proposed. Assuming that the channel state information is known at the source nodes, transmit antenna selection and maximal ratio combining (MRC) are employed when source nodes transmit information to the relay node and receive information from the relay node respectively, in order to improve the overall signal-to-interference plus noise ratio (SINR). Analytical expressions are derived for tight upper bound SINR at the relay node and source nodes upon reception. Further, losed form expressions are also derived for end-to-end outage probability of the proposed bidirectional full-duplex AF relay network in the Nakagami-m fading channel environment. Although self-interference at the relay node limits the performance of the full-duplex network, the outage performance of the proposed network is better than that of conventional bidirectional full-duplex and half-duplex AF relay networks, due to the selection diversity gain in TAS and diversity and array gain in MRC

Power Allocation Strategies for Wireless Relay Networks with Analog Network Coding: Survey

Relay aided communication with network coding can bring spectacular performance enhancements for wireless networks. The proper design of power allocated to each of the nodes involved in the communication is essential as it has impact on the performance when Analog Network coding (ANC) is used. This paper presents a survey on recent power allocation strategies, intended objectives, practical constraints that have been considered, and corresponding performances for networks with ANC protocol

Design Of Vehicular Communication Systems Employing Physical Layer Network Coding Over Cascaded Fading Channels

Tez (Doktora) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2017Thesis (Ph.D.) -- İstanbul Technical University, Institute of Science and Technology, 2017İnsandan insana ses taşıma odaklı ikinci nesil (2nd Generation, 2G) mobil haberleşme teknolojilerinin kaydettiği başarıdan sonra telsiz iletişim alanındaki eğilimler insandan-makinaya olarak adlandırılan veri taşıma odaklı telsiz iletişim teknolojilerine (3rd Generation, 3G) doğru yönelmiştir. Bu veri taşıma odaklı iletişim konsepti ile birlikte son kullanıcılar multi-media mesajlaşma, internet erişimi, e-ticaret ve video paylaşımı gibi çok çeşitli telsiz iletişim servislerine kavuşma imkanı buldular. Telsiz iletişimdeki başarılı ve hızlı ilerlemenin bir sonucu olarak günümüzde bu alanda yapılan araştırma-geliştirme çalışmalarının yönü yüksek veri iletim hızları (>100Mb/s) ve daha yüksek bant-verimliliği (>10b/s) gerektiren makineden-makineye (Mactine-to-Machine, M2M) telsiz iletişime doğru yönelmiş bulunmaktadır. M2M telsiz iletişiminde bir araştırma/uygulama alanı araçtan-nesnelere (Vehicle-to-things, V2X) haberleşmedir. Araçtan araca (Vehicle-to-Vehicle, V2V) ve araçtan yol kenarındaki baz istasyonuna (Vehicle-to-Infrastructure, V2I) olmak üzere iki haberleşme sistemini birlikte içeren V2X haberleşme sistemleri günümüzde özellikle büyük metropollerde günlük hayatı pek çok yönden olumsuz etkileyen trafik kaynaklı problemlere karşı getirdiği çözüm önerileri nedeniyle üniversitlerde teorik çalışmalar yapan araştırmacıların yanı sıra, resmi kurumların, standartları belirleyen organizasyonların ve özellille otomotiv ve bilişim endüstrisindeki şirketlerin gittikçe artan dikkatini çekmeyi başarmıştır. Araçlar arası haberleşme teknolojilerinin gelişimine ivme kazandıran önemli gelişmelere bakılacak olursa; 1999 yılında ABD’de Federal Communication Comission (FCC) 5.9GHz frekans bandında 75MHz’lik bir frekans bandının V2X haberleşme için kullanımını onaylamıştır. 2008 yılında ise Avrupa haberleşme standardları enstitüsü (European Telecommunication Standards Institute) yine 5.9GHz frekans bandında 30Mhz’lik bir bandın bu amaçla kullanılmasını önermiştir. FCC’nin 2003 yılında ITS (Intelligent Transportation Systems) uygulamalarında kullanılacak haberleşme birimleri için yayımladığı rapor ve talebin ardından DSRC (Dedicated Short Range Communication) olarak adlandırılan V2X haberleşme sistemlerinin standardizasyonu için çalışmalar başlamış ve 2004 yılında IEEE 802.11standardı temel alınarak geliştirilen IEEE 802.11p standardı WAVE (Wireless Access in Vehicular Environments) olarak da bilinen adıyla 2010 yılında kabul edilmiştir. Bugün artık pek çok üniversitede çeşitli araştırma grupları V2X haberleşme üzerine akademik çalışmalar yürütürken endüstriyel seviyede ise Avrupa’da örneğin büyük ölçekli Avrupa Birliği projeleri olarak CAR2CAR Communication Corsortium, Secure Vehicular Communication ve NEARCTIS yürütülmektedir. Amerika’da ise ulaştırma bakanlığının desteklediği IntelliDrive projesi ile güvenlik, mobil iletişim ve çevre koruma amaçlı hedefler doğrultusunda trafik altyapısı, araçlar ve yolcuların mobil haberleşme cihazları arasında haberleşmeyi sağlayacak bir telsiz iletişim ağı alt yapısı kurma çalışmaları sürdürülmektedir. Benzer çalışmalar Japon Otomobil Teknolojileri Araştırma Enstitüsü JARI tarafından da yapılmaktadır. Yine V2V haberleşmenin trafik güvenliğini arttırmadaki öneminin anlaşılmasından sonra lider otomobil üreticisi firmalar “Crash Avoidance Metrics Partnership” adını verdikleri proje için ortak çatı altında biraraya gelmişlerdir. Kısaca belirtilmek istenirse, telsiz iletişim alanında V2X haberleşme yeni ama oldukça önemli bir çalışma alanı olarak görülmektedir. Günümüz telsiz haberleşme teknolojilerinden biri olan araçtan araca haberleşme, trafik verimliliğini arttırma, kazaların azaltılması ve trafikte güvenli sürüş konulara çözümler sağlayacak akıllı taşıma sistemlerinin gerçeklenmesinde çekirdek teknoloji konumundadır. Hücresel haberleşme ile karşılaştırıldığında, V2V haberleşme bazı yeni zorlukları içerir. V2V haberleşme kanallarının istatistiksel özellikleri hücresel telsiz haberleşme kanallarının istatistiksel özelliklerinden farklıdır. Bu nedenle, Rayleigh, Rician ve Nakagami-m gibi iyi bilinen hücresel haberleşme kanal modelleri V2V haberleşme kanallarındaki sönümlemeyi modellemek için uygun değildir. Yapılan saha ölçümlerinden görüldüğü üzere, V2V haberleşme kanallarında kanal kazancı, hareketli kaynaklar etrafında, her biri ayrı bir işaret kaynağı gibi davranan birbirinden bağımsız saçıcı gupların oluşturduğu sanal kanalların kanal kazançlarının çarpımından meydana gelmektedir. Kanal kazancının bu çarpımsallık niteliğinden dolayı V2V haberleşme kanalları kaskad sönümlemeli kanal modeli olarak adlandırılan bir grup kanal modeli ile modellenmelidirler. V2V haberleşmede karşılaşılan zorlukların bir nedeni, gerek haberleşen araçların gerekse onların etrafındaki diğer araçların yüksek hızlardaki hareketliliği nedeniyle haberleşme ortamının çevresel olarak çok hızlı değişmesidir. Bunun yanısıra araç antenlerinin görece düşük yükseklikte olmasının da etkisiyle, özellikle yerleşim birimleri içindeki yoğun trafik şartları düşünüldüğünde, haberleşen araçlar arasında çoğu zaman doğrudan görüş olmayacaktır. Bu da iletişimin sürekliliği ve güvenilirliği açısından işbirlikli haberleşmeyi kaçınılmaz kılmaktadır. Ancak doğrudan haberleşmeye nazaran daha fazla zaman dilimi gereksinimi işbirlikli sistemlerin temel dezavantajıdır. Veri iletim hızında kayba neden olan bu dezavantajı yok etmenin bir yolu, iki haberleşme biriminin aynı zaman aralığında aynı röle üzerinden veri aktarmasına imkan tanıyan fiziksel katman ağ kodlama (Physical Layer Network Coding, PLNC) tekniğidir. Ani gelişen durumların çok sayıda kullanıcıya kısa sürede bildirilmesini gerektirecek trafik içi haberleşmede PLNC tekniği yüksek başarımlı V2V haberleşme sistemlerinin tasarımında önemli bir rol oynayacaktır. Bu tezde sunulan çalışmalar üç grupta ele alınabilir. Birinci gruptaki ilk çalışmada tek antenli tek röleli ve röle üzerinde sabit kazançlı kuvvetlendir-ve-aktar tekniği kullanılarak PLNC yapılan bir işbirlikli V2V haberleşme sistemi tasarlanmıştır. Sistemin performans analizleri kaskad Nakagami-m kanal modeli varsayımı altında yapılmış olup bu kanal modeli, araçlar arası haberleşmeye uygun olan çift Rayleigh, kaskad Rayleigh, çift Nakagami-m ve genelleştirilmiş-K kanal modellerinin yanı sıra geleneksel hücresel haberleşme kanal modellerini de kapsamaktadır. Dolayısıyla bu çalışmada elde edilen sonuçlar bu kanal modelleri için de geçerlidir. Sistemin hata performans analizleri yapılırken öncelikle uçtan-uca işaret gürültü oranına ait birikimsel olasılık dağılım fonksiyonu kapalı formda elde edilmiş, ardından bu dağılım fonksiyonu kullanılarak sistemin servis kesinti olasılığı ve çeşitli modülasyon tipleri için sembol hata olasılığı ifadeleri kapalı formda bulunmuştur. Bu analizlerin bir devamı olarak, birinci grupta yapılan ikinci çalışmada ise, kaynaklarda öz-girişim işaretinin tam olarak yok edilemediği durumlar için yine tek antenli tek röleli rölede sabit kazançlı kuvvetlendir-ve-aktar tekniği kullanılarak PLNC yapılan sistemin performans analizi kaskad ve hızlı sönümlemeli Rayleigh kanal varsayımı altında yapılmış ve sisteme ait servis kesinti olasılığı ifadesi kapalı formda elde edilerek öz girişimin sistem performansına etkileri incelenmiştir. Tezde yer alan ikinci grup çalışmada, çok girişli çok çıkışlı (multiple input multiple output, MIMO) bir V2V haberleşme sistemi tasarlanmıştır. Sistemde birden çok röle olup kaynaklar ve tüm röleler çok antenlidir. Ayrıca röleler değişken kazançlı kuvvetlendir-ve-aktar tekniği uygulayarak PLNC yapmaktadır. Bu çalışmada da kaskad Nakagami-m kanal modeli kullanıldığından elde edilen sonuçlar yukarıda bahsedilen diğer kaskad veya kaskad olmayan kanal modelleri için de geçerlidir. Burada yapılan analizler ile tüm sistemin servis kesinti performansı kaynakların ortak servis kesinti olasılıkları cinsinden ifade edilerek bu olasılık tek katlı integral formunda bulunmuştur. Ardından servis kesinti olasılığı için alt ve üst sınır ifadeleri kapalı formda elde edilmiştir. Bulunan sınır ifadeleri aracılığıyla sistemde elde edilebilecek çeşitleme derecesi, röle sayısı, kaynak ve rölelerde kullanılan anten sayıları ve kanalların kaskadlık dereceleri ve sönümleme parametrelerinin aldığı değerlere bağlı olarak sistem parametreleri cinsinden ifade edilmiştir. Tasarlanan bu sistem ile ortak anten ve röle seçimi yapılarak V2V haberleşme sistemlerinin performansının daha da iyileştirilebileceği gösterilmiştir. Tezde yapılan üçüncü çalışmada PLNC yapılan bir çok antenli çok röleli V2V haberleşme sisteminde uzay-zaman kafes kodlama tekniği kullanılarak sistem performansının daha da iyileştirilmesi sağlanmıştır. Bu amaçla öncelikle sistemin çiftsel hata olasılığı için bir üst sınır ifadesi çift Rayleigh sönümlemeli kanal varsayımı için elde edilmiştir. Daha sonra bu olasılığı en küçük yapacak kodların inşaası için yeni bir kod tasarım ölçütü türetilmiş ve bu ölçüt kullanılarak çift Rayleigh sönümlemeli kanallarda PLNC tekniği kullanan MIMO V2V haberleşme sistemler için 4 ve 8 durumlu yeni uzay-zaman kafes kodları bulunmuştur.As a current state-of-the-art in wireless communications, Vehicle-to-Vehicle (V2V) communications is the core technology to build the intelligent transportation infrastructures promising the solutions to the issues such as traffic efficiency increasing, accident reduction and safety improvements. In comparison with the cellular wireless communication, there are some new challenges within the V2V communication. The statistical properties of the V2V communication channels differ from those of the cellular channels. Thereby, well known cellular channel models such as Rayleigh, Rician and Nakagami-m are not appropriate to simulate the fading in V2V communication channels. Field measurements reveal that V2V communication channels can be modeled by a class of channel models where the gain is obtained by multiplying the gains of virtual channels produced by each individual scattering group around that behaves as an independent signal source. Due to their multiplicativity nature, V2V communication channels are named as cascaded fading channels. A major challenge in V2V communications is that the physical environment is unsettled due to the mobility of the wireless units and other vehicles around these units. Additionally, the vehicle antennas have relatively lower heights. Therefore, especially considering the traffic in urban areas, most of the time there will be no line-of-sight between the communicating vehicles. This makes cooperative communications inevitable for seamless and reliable communication among the moving vehicles. And yet, compared to non-cooperative communication, the cooperation protocols require more time slots, which results in a decrease in data transmission rate. A method to cope with this drawback is physical layer network coding (PLNC) providing the simultaneous data transmissions of the vehicles via the same relay. The PLNC method will play an important role in the design of the high performance V2V communication systems serving in the heavy traffic conditions when a large number of users need to be notified about suddenly changing situations. Studies presented in this thesis can be divided into three categories. In the first category, a cooperative V2V communication system employing PLNC using fixed gain amplify-and-forward technique is proposed and its outage and error performance analysis is investigated. Analytic results are derived under the cascaded Nakagami-m fading channel model assumption covering double Rayleigh, cascaded Rayleigh, double Nakagami-m, generalized-K and conventional cellular channel models as well. Therefore, the results obtained by this work are also valid for all these channel models. In the error performance investigation of the proposed system, first, exact cumulative density function of the end to end signal to noise ratio is derived. Then, using this cumulative density function, the exact closed-form outage probability is obtained. Then the exact closed-form symbol error rate expression for various modulation types is derived. As a continuation of this work, the performance analysis of the same system is investigated for not only cascaded but also fast fading Rayleigh channels in the presence of the self-interference. Thus the exact closed-form outage probability expression is obtained, and it is shown that the self-interference may cause the error floor in the performance of the network coded communication systems. In the second category, a multiple input multiple output (MIMO) V2V communication system is proposed. In this proposed system, all source and relay vehicles have multiple antennas while the relays employ the PLNC method using variable gain amplify-and-forward technique. The analytic results are derived for the cascaded Nakagami-m fading channels, and therefore the result of this work are held for the cascaded and non-cascaded channels, as mentioned above. Furthermore, the performance of the system is evaluated in terms of joint outage probability of the sources, and the exact outage probability expression is obtained in a single integral form while the upper and the lower bounds of the outage probability are obtained in the closed-form. Moreover, asymptotic diversity order is quantified as a function of the number of the relays, the number of the antennas at the sources and the relays, and the channel parameters which are cascading degree and fading parameter values. Within this system, it is shown that the service outage probability performance can be enhanced by employing joint antenna and relay selection. In the third category, PLNC and space-time trellis coding (STTC) techniques are combined to improve the error performance of a multi-antenna multi-relay V2V system. The upper bound expression of the pairwise error probability of the system is evaluated for double Rayleigh fading channels. Then using the upper bound expression, a novel code-design criterion is derived for cascaded fading channels. Then, by using this new criterion, a novel STTCs with 4 and 8 states are proposed for MIMO V2V PLNC systems.DoktoraPh.D

A Review- Proposed Bidirectional Relaying for Improved Channel Estimation Error and Co-Channel Interference

Wireless Communication has gained a lot of interest as future generation requires higher data rates and more suitable transmission with adequate quality of service. Wireless communication suffers from various problems like Co-Channel Interference (CCI) and Channel Estimation Error (CEE). Cooperative communication is an efficient technique to deal with these types of problems by offering significant multiplexing and diversity gains without increasing power and bandwidth. Our proposed two way relaying helps to improve the overall system performance in wireless networks. Cooperative communications also deals with the various problems like fading and shadowing. It is further investigated that proposed two way relaying is spectrally efficient technique which provides a way to surmount half duplexing loss in one way relay channel

Performance Analysis, Resource Allocation and Optimization of Cooperative Communication Systems under Generalized Fading Channels

The increasing demands for high-speed data transmission, efficient wireless access, high quality of service (QoS) and reliable network coverage with reduced power consumption impose demanding intensive research efforts on the design of novel wireless communication system architectures. A notable development in the area of communication theory is the introduction of cooperative communication systems. These technologies become promising solution for the next-generation wireless transmission systems due to their applicability in size, power, hardware and price constrained devices, such as cellular mobile devices, wireless sensors, ad-hoc networks and military communications, being able to provide, e.g., diversity gain against fading channels without the need for installing multiple antennas in a single terminal. The performance of the cooperative systems can in general be significantly increased by allocating the limited power efficiently. In this thesis, we address in detail the performance analysis, resource allocation and optimization of such cooperative communication systems under generalized fading channels. We focus first on energy-efficiency (EE) optimization and optimal power allocation (OPA) of regenerative cooperative network with spatial correlation effects under given power constraint and QoS requirement. The thesis also investigates the end-to-end performance and power allocation of a regenerative multi-relay cooperative network over non-homogeneous scattering environment, which is realistic case in practical wireless communication scenarios. Furthermore, the study investigates the end-to-end performance, OPA and energy optimization analysis under total power constraint and performance requirement of full-duplex (FD) relaying transmission scheme over asymmetric generalized fading models with relay self-interference (SI) effects.The study first focuses on exact error analysis and EE optimization of regenerative relay systems under spatial correlation effects. It first derives novel exact and asymptotic expressions for the symbol-error-rates (SERs) of M -ary quadrature amplitude and M -ary phase-shift keying (M -QAM) and (M -PSK) modulations, respectively, assuming a dual-hop decode-and-forward relay system, spatial correlation, path-loss effects and maximum-ratio-combing (MRC) at the destination. Based on this, EEoptimization and OPA are carried out under certain QoS requirement and transmit power constraints.Furthermore, the second part of the study investigates the end-to-end performance and power allocation of MRC based regenerative multi-relay cooperative system over non-homogeneous scattering environment. Novel exact and asymptotic expressions are derived for the end-to-end average SER for M -QAM and M -PSK modulations.The offered results are employed in performance investigations and power allocation formulations under total transmit power constraints.Finally, the thesis investigates outage performance, OPA and energy optimization analysis under certain system constraints for the FD and half-duplex (HD) relaying systems. Unlike the previous studies that considered the scenario of information transmission over symmetric fading conditions, in this study we considered the scenario of information transmission over the most generalized asymmetric fading environments.The obtained results indicate that depending on the severity of multipath fading, the spatial correlation between the direct and relayed paths and the relay location, the direct transmission is more energy-efficient only for rather short transmission distances and until a certain threshold. Beyond this, the system benefits substantially from the cooperative transmission approach where the cooperation gain increases as the transmission distance increases. Furthermore, the investigations on the power allocation for the multi-relay system over the generalized small-scale fading model show that substantial performance gain can be achieved by the proposed power allocation scheme over the conventional equal power allocation (EPA) scheme when the source-relay and relay-destination paths are highly unbalanced. Extensive studies on the FD relay system also show that OPA provides significant performance gain over the EPA scheme when the relay SI level is relatively strong. In addition, it is shown that the FD relaying scheme is more energy-efficient than the reference HD relaying scheme at long transmission distances and for moderate relay SI levels.In general, the investigations in this thesis provide tools, results and useful insights for implementing space-efficient, low-cost and energy-efficient cooperative networks, specifically, towards the future green communication era where the optimization of the scarce resources is critical

Full-duplex wireless communications: challenges, solutions and future research directions

The family of conventional half-duplex (HD) wireless systems relied on transmitting and receiving in different time-slots or frequency sub-bands. Hence the wireless research community aspires to conceive full-duplex (FD) operation for supporting concurrent transmission and reception in a single time/frequency channel, which would improve the attainable spectral efficiency by a factor of two. The main challenge encountered in implementing an FD wireless device is the large power difference between the self-interference (SI) imposed by the device’s own transmissions and the signal of interest received from a remote source. In this survey, we present a comprehensive list of the potential FD techniques and highlight their pros and cons. We classify the SI cancellation techniques into three categories, namely passive suppression, analog cancellation and digital cancellation, with the advantages and disadvantages of each technique compared. Specifically, we analyse the main impairments (e.g. phase noise, power amplifier nonlinearity as well as in-phase and quadrature-phase (I/Q) imbalance, etc.) that degrading the SI cancellation. We then discuss the FD based Media Access Control (MAC)-layer protocol design for the sake of addressing some of the critical issues, such as the problem of hidden terminals, the resultant end-to-end delay and the high packet loss ratio (PLR) due to network congestion. After elaborating on a variety of physical/MAC-layer techniques, we discuss potential solutions conceived for meeting the challenges imposed by the aforementioned techniques. Furthermore, we also discuss a range of critical issues related to the implementation, performance enhancement and optimization of FD systems, including important topics such as hybrid FD/HD scheme, optimal relay selection and optimal power allocation, etc. Finally, a variety of new directions and open problems associated with FD technology are pointed out. Our hope is that this treatise will stimulate future research efforts in the emerging field of FD communication

Energy harvesting over Rician fading channel: A performance analysis for half-duplex bidirectional sensor networks under hardware impairments

In this paper, a rigorous analysis of the performance of time-switching energy harvesting strategy that is applied for a half-duplex bidirectional wireless sensor network with intermediate relay over a Rician fading channel is presented to provide the exact-form expressions of the outage probability, achievable throughput and the symbol-error-rate (SER) of the system under the hardware impairment condition. Using the proposed probabilistic models for wireless channels between mobile nodes as well as for the hardware noises, we derive the outage probability of the system, and then the throughput and SER can be obtained as a result. Both exact analysis and asymptotic analysis at high signal-power-to-noise-ratio regime are provided. Monte Carlo simulation is also conducted to verify the analysis. This work confirms the effectiveness of energy harvesting applied in wireless sensor networks over a Rician fading channel, and can provide an insightful understanding about the effect of various parameters on the system performance.Web of Science186art. no. 1781

Outage Probability of Multi-hop Networks with Amplify-and-Forward Full-duplex Relaying

abstract: Full-duplex communication has attracted significant attention as it promises to increase the spectral efficiency compared to half-duplex. Multi-hop full-duplex networks add new dimensions and capabilities to cooperative networks by facilitating simultaneous transmission and reception and improving data rates. When a relay in a multi-hop full-duplex system amplifies and forwards its received signals, due to the presence of self-interference, the input-output relationship is determined by recursive equations. This thesis introduces a signal flow graph approach to solve the problem of finding the input-output relationship of a multi-hop amplify-and-forward full-duplex relaying system using Mason's gain formula. Even when all links have flat fading channels, the residual self-interference component due to imperfect self-interference cancellation at the relays results in an end-to-end effective channel that is an all-pole frequency-selective channel. Also, by assuming the relay channels undergo frequency-selective fading, the outage probability analysis is performed and the performance is compared with the case when the relay channels undergo frequency-flat fading. The outage performance of this system is performed assuming that the destination employs an equalizer or a matched filter. For the case of a two-hop (single relay) full-duplex amplify-and-forward relaying system, the bounds on the outage probability are derived by assuming that the destination employs a matched filter or a minimum mean squared error decision feedback equalizer. For the case of a three-hop (two-relay) system with frequency-flat relay channels, the outage probability analysis is performed by considering the output SNR of different types of equalizers and matched filter at the destination. Also, the closed-form upper bounds on the output SNR are derived when the destination employs a minimum mean squared error decision feedback equalizer which is used in outage probability analysis. It is seen that for sufficiently high target rates, full-duplex relaying with equalizers is always better than half-duplex relaying in terms of achieving lower outage probability, despite the higher RSI. In contrast, since full-duplex relaying with MF is sensitive to RSI, it is outperformed by half-duplex relaying under strong RSI.Dissertation/ThesisMasters Thesis Electrical Engineering 201

Performance Analysis in Full-Duplex Relaying Systems withWireless Power Transfer

Energy harvesting (EH) technology has become increasingly attractive as an appealing solution to provide long-lasting power for energy-constrained wireless cooperative sensor networks. EH in such networks is particularly important as it can enable information relaying. Different from absorbing energy from intermittent and unpredictable nature, such as solar, wind, and vibration, harvesting from radio frequency (RF) radiated by ambient transmitters has received tremendous attention. The RF signal can convey both information and energy at the same time, which facilitates the development of simultaneous wireless information and power transfer. Besides, ambient RF is widely available from the base station, WIFI, and mobile phone in the current information era. However, some open issues associated with EH are existing in the state-of-art. One of the key challenges is rapid energy loss during the transferring process, especially for long-distance transmission. The other challenge is the design of protocols to optimally coordinate between information and power transmission. Meanwhile, in-band full-duplex (IBFD) communication have gained considerable attraction by researchers, which has the ability to improve system spectral efficiency. IBFD can receive information and forward information at the same time on the same frequency. Since the RF signal can be superimposed, the antenna of the IBFD system receives the RF signal from both desired transmitter and local transmitter. Due to the short distance of the local transmission signals, the received signal power is much larger than the desired transmission signals, which results in faulty receiving of the desired signals. Therefore, it is of great significance to study the local self-interference cancellation method of the IBFD system. In the recent state-of-art, three main types of self-interference cancellations are researched, which are passive cancellations, digital cancellations, and analog cancellations. In this thesis, we study polarization-enabled digital self-interference cancellation (PDC) scheme in IBFD EH systems which cancels self-interference by antenna polarization (propagation domain) and digital processing (digital domain). The theme of this thesis is to address the following two questions: how the selfinterference would be canceled in the IBFD EH system and how to optimize key performances of the system to optimal system performances. This thesis makes five research contributions in the important area of IBFD relaying systems with wireless power transfer. Their applications are primarily in the domains of the Internet of Things (IoT) and 5G-and-beyond wireless networks. The overarching objective of the thesis is to construct analytical system models and evaluate system performance (outage probability, throughput, error) in various scenarios. In all five contributions, system models and analytical expressions of the performance metrics are derived, followed by computer simulations for performance analysis