Sum-Rate Maximization of RSMA-based Aerial Communications with Energy Harvesting: A Reinforcement Learning Approach

In this letter, we investigate a joint power and beamforming design problem for rate-splitting multiple access (RSMA)-based aerial communications with energy harvesting, where a self-sustainable aerial base station serves multiple users by utilizing the harvested energy. Considering maximizing the sum-rate from the long-term perspective, we utilize a deep reinforcement learning (DRL) approach, namely the soft actor-critic algorithm, to restrict the maximum transmission power at each time based on the stochastic property of the channel environment, harvested energy, and battery power information. Moreover, for designing precoders and power allocation among all the private/common streams of the RSMA, we employ sequential least squares programming (SLSQP) using the Han-Powell quasi-Newton method to maximize the sum-rate for the given transmission power via DRL. Numerical results show the superiority of the proposed scheme over several baseline methods in terms of the average sum-rate performance.Comment: 13 pages, 4 figures, submitted to IEEE Wireless Communications Letter

A Tutorial on Nonorthogonal Multiple Access for 5G and Beyond

Today's wireless networks allocate radio resources to users based on the orthogonal multiple access (OMA) principle. However, as the number of users increases, OMA based approaches may not meet the stringent emerging requirements including very high spectral efficiency, very low latency, and massive device connectivity. Nonorthogonal multiple access (NOMA) principle emerges as a solution to improve the spectral efficiency while allowing some degree of multiple access interference at receivers. In this tutorial style paper, we target providing a unified model for NOMA, including uplink and downlink transmissions, along with the extensions tomultiple inputmultiple output and cooperative communication scenarios. Through numerical examples, we compare the performances of OMA and NOMA networks. Implementation aspects and open issues are also detailed.Comment: 25 pages, 10 figure

Indexed Multiple Access with Reconfigurable Intelligent Surfaces: The Reflection Tuning Potential

Indexed modulation (IM) is an evolving technique that has become popular due to its ability of parallel data communication over distinct combinations of transmission entities. In this article, we first provide a comprehensive survey of IM-enabled multiple access (MA) techniques, emphasizing the shortcomings of existing non-indexed MA schemes. Theoretical comparisons are presented to show how the notion of indexing eliminates the limitations of non-indexed solutions. We also discuss the benefits that the utilization of a reconfigurable intelligent surface (RIS) can offer when deployed as an indexing entity. In particular, we propose an RIS-indexed multiple access (RIMA) transmission scheme that utilizes dynamic phase tuning to embed multi-user information over a single carrier. The performance of the proposed RIMA is assessed in light of simulation results that confirm its performance gains. The article further includes a list of relevant open technical issues and research directions.Comment: 7 pages, 5 figures, 1 tabl

Synergizing Airborne Non-Terrestrial Networks and Reconfigurable Intelligent Surfaces-Aided 6G IoT

On the one hand, Reconfigurable Intelligent Surfaces (RISs) emerge as a promising solution to meet the demand for higher data rates, improved coverage, and efficient spectrum utilization. On the other hand, Non-Terrestrial Networks (NTNs) offer unprecedented possibilities for global connectivity. Moreover, the NTN can also support the upsurge in the number of Internet of Things (IoT) devices by providing reliable and ubiquitous connectivity. Although NTNs have shown promising results, there are several challenges associated with their usage, such as signal propagation delays, interference, security, etc. In this article, we have discussed the possibilities of integrating RIS with an NTN platform to overcome the issues associated with NTN. Furthermore, through experimental validation, we have demonstrated that the RIS-assisted NTN can play a pivotal role in improving the performance of the entire communication system.Comment: 15 pages, 5 figure

Performance of joint relay and antenna selection in the full-duplex amplify-and-forward relay networks

Tam-Çift Yönlü röle tekniği, sistemin spektral kazancının artırılmasına ve band kayıplarının üstesinden gelinmesine yardımcı olurken, rölenin eşzamanlı iletim ve alım özelliğinden kaynaklanan verici ve alıcı antenleri arasında oluşan çevrim karışımından olumsuz etkilenmektedir. Bu tez çalışmasında ortak röle ve anten seçiminin iki atlamalı Tam-Çift Yönlü Kuvvetlendir-ve-Aktar tipi röle ağları üzerindeki performansı bağımsız ve aynı dağılımlı Rayleigh sönümlemeli kanallarda incelenmiştir. Anten seçimi için maks-maks anten seçim tekniği kullanılırken röle seçimi için en iyi röle seçimi, kısmi röle seçimi ve reaktif röle seçimi teknikleri kullanılmış ve birbirleriyle karşılaştırılmıştır. Sistemlerin performansları servis kesilme olasılığı ve bit hata olasılığı üzerinden değerlendirilmiştir. Bununla birlikte servis kesilme olasılığı için sistemin asimptotik performansı da incelenmiştir. Elde edilen teorik sonuçlar Monte Carlo benzetimleri yardımıyla doğrulanmıştır. Ortak röle ve anten seçim tekniğinin sistem performansını iyileştirdiği ve düşük işaret-gürültü oranlarında çeşitleme kazancı sağladığı gösterilmiştir.While Full-Duplex relaying technique aids to overcome the associated bandwidth loss and improve spectral efficiency of the system, suffers from a loop interference due to signal leakage between transmit and receive antennas at the relay arising from simultaneous transmission and reception. In this thesis study, performance of the joint relay and antenna selection in the dual-hop Full-Duplex Amplify-and-Forward relay networks has been investigated in independent and identically distributed Rayleigh fading channels. While max-max antenna selection technique has been used for antenna selection; best relay selection, partial relay selection and reactive relay selection techniques have been used for relay selection and compared with each other. Performances of systems have been evaluated in terms of outage probability and bit error rate. Besides, asymptotic performances have been investigated for outage probabilities. Theoretical results are validated by Monte Carlo simulations. It has been shown that the joint relay and antenna selection technique improves the performance of the system and provides the diversity order gain at low signal-to-noise ratios. …ÖZET ............................................................................................................................... iv SUMMARY ...................................................................................................................... v ÖN SÖZ ........................................................................................................................... vi İÇİNDEKİLER DİZİNİ .................................................................................................. vii ŞEKİLLER DİZİNİ ......................................................................................................... ix SİMGELER VE KISALTMALAR ............................................................................... xiii BÖLÜM I GİRİŞ .............................................................................................................. 1 BÖLÜM II TELSİZ HABERLEŞME KANALI .............................................................. 7 2.1 Rayleigh Sönümlemeli Kanal ................................................................................... 11 2.2 Ricean Sönümlemeli Kanal ...................................................................................... 12 2.3 Nakagami-m Sönümlemeli Kanal ............................................................................. 12 2.4 Sönümlemeli Kanallarda Hata Performansı ............................................................. 13 BÖLÜM III ANTEN ÇEŞİTLEMELİ VE RÖLELİ HABERLEŞME TEKNİKLERİ .. 18 3.1 Alıcı Anten Çeşitlemeli Haberleşme Teknikleri ....................................................... 18 3.1.1 Seçmeli birleştirme (SC) ................................................................................. 19 3.1.2 En büyük oranlı birleştirme (MRC) ................................................................ 21 3.1.3 Eşit kazançlı birleştirme (EGC) ...................................................................... 23 3.1.4 Genelleştirilmiş seçmeli birleştirme (GSC) .................................................... 25 3.1.5 Alıcı anten çeşitlemeli haberleşme tekniklerinin hata performansı ................ 27 3.2 Verici Anten Çeşitlemeli Haberleşme Teknikleri ..................................................... 32 3.2.1 Dik uzay-zaman blok kodlama tekniği (OSTBC) ........................................... 32 3.2.2 Verici anten seçimi (TAS) .............................................................................. 37 3.2.3 Maksimum-oranlı iletim (MRT) ..................................................................... 39 3.2.4 Verici anten çeşitlemeli haberleşme tekniklerinin hata performansı .............. 41 3.3 Hibrit Anten Çeşitlemeli Haberleşme Teknikleri ..................................................... 46 3.3.1 Ortak tek verici ve alıcı anten seçimi (JTRAS) .............................................. 46 3.3.2 TAS/MRC tekniği ........................................................................................... 47 3.3.3 TAS/OSTBC tekniği ....................................................................................... 49 3.3.4 Hibrit anten çeşitlemeli haberleşme tekniklerinin hata performansı ............... 53 3.4 Röleli Haberleşme Teknikleri ................................................................................... 58 viii 3.4.1 İki-atlamalı TAS/MRC .................................................................................... 61 3.4.2 İki-atlamalı TAS/GSC ..................................................................................... 63 3.4.3 İki-atlamalı OSTBC/MRC .............................................................................. 65 3.4.4 İki-atlamalı röleli haberleşme tekniklerinin hata performansı ........................ 67 3.4.5 İki-atlamalı röleli haberleşmede röle seçim teknikleri .................................... 72 3.4.5.1 En iyi röle seçimi (BRS) ..................................................................... 72 3.4.5.2 Kısmi röle seçimi (PRS) ..................................................................... 72 3.4.5.3 Reaktif röle seçimi (RRS) .................................................................. 73 3.4.5.4 İki-atlamalı röleli haberleşmede röle seçim tekniklerinin hata performansı ...................................................................................... 73 BÖLÜM IV ORTAK RÖLE VE ANTEN SEÇİMİNİN TAM-ÇİFT YÖNLÜ KUVVETLENDİR-VE-AKTAR TİPİ RÖLELİ AĞLARDA RAYLEIGH KANAL İÇİN PERFORMANSI ................................................................................................... 75 4.1 İki-Atlamalı Tam-Çift Yönlü Röle Sistem Modeli ................................................... 75 4.2 Ortak Röle ve Anten Seçim Tekniği (JRAS) ............................................................ 78 4.2.1 En iyi röle seçimi (BRS) ................................................................................. 78 4.2.2 Kısmi röle seçimi (PRS) .................................................................................. 78 4.2.3 Reaktif röle seçimi (RRS) ............................................................................... 79 4.3 Performans Analizi ................................................................................................... 79 4.3.1 Servis kesilme olasılığı ................................................................................... 79 4.3.1.1 BRS tekniği için servis kesilme olasılığı ............................................ 80 4.3.1.2 PRS tekniği için servis kesilme olasılığı ............................................ 82 4.3.1.3 RRS tekniği için servis kesilme olasılığı ............................................ 83 4.3.2 Ortalama hata olasılığı .................................................................................... 84 4.3.3 Asimptotik analiz ............................................................................................ 86 4.4 Teorik ve Benzetim Sonuçları .................................................................................. 89 BÖLÜM V SONUÇLAR ................................................................................................ 93 KAYNAKLAR ............................................................................................................... 95 ÖZGEÇMİŞ .................................................................................................................. 103 TEZ ÇALIŞMASINDAN ÜRETİLEN ESERLER ...................................................... 10

Outage Performance of Dual Hop Full-Duplex MIMO Relay Networks with TAS/MRC over Rayleigh Fading Channels

13th International Symposium on Wireless Communication Systems (ISWCS) -- SEP 20-23, 2016 -- Poznan, POLANDWOS: 000386654000019In this paper, we investigate end-to-end (e2e) outage probability (OP) performance of dual hop full-duplex (FD) amplify-and-forward (AF) relay network with transmit antenna selection (TAS) and maximal-ratio combining (MRC) over independent identically distributed Rayleigh fading channels. In the network, source and destination are equipped with multiple antennas, and communicate with each other via a single relay, which is equipped with one receive and one transmit antennas. We assume that the direct link between the source and destination is not available. For signal transmission, TAS is used at the source by neglecting residual self-interference (RSI) effect and maximal-ratio combining (MRC) technique is employed at the destination for combining received signals. In order to simplify the theoretical derivations, we also investigate the e2e OP in case that the RSI is non-fading. OP expression is derived in integral form for the Rayleigh faded RSI effect. Moreover, in case of non-fading RSI effect, OP expression is derived in closed form. The analytical results are verified by the Monte Carlo simulations

Outage Probability of Full-Duplex MIMO Relay Networks with Co-channel Interference over Rayleigh Fading Channels

24th Signal Processing and Communication Application Conference (SIU) -- MAY 16-19, 2016 -- Zonguldak, TURKEYWOS: 000391250900272In this work, the outage probability of dual-hop full-duplex amplify-and-forward MIMO relay network is examined in the presence of co-channel interference at the relay over Rayleigh fading channels. The source and destination are equipped with multiple antennas and the relay is equipped with single receive and single transmit antennas. The effects of Rayleigh faded multiple co-channel interferences and self-interference between transmit/receive antennas of the relay are considered. In this relay network, transmit antenna selection at the source and maximal-ratio combining technique at the destination are employed. The outage probability of the relay network is examined via Monte Carlo simulations.IEEE, Bulent Ecevit Univ, Dept Elect & Elect Engn, Bulent Ecevit Univ, Dept Biomed Engn, Bulent Ecevit Univ, Dept Comp Eng

Performance of Joint Relay and Antenna Selection in the Full-Duplex Amplify-and-Forward Relay Networks

23nd Signal Processing and Communications Applications Conference (SIU) -- MAY 16-19, 2015 -- Inonu Univ, Malatya, TURKEYWOS: 000380500900144In this work, joint relay and antenna selection (JRAS) problem in Full-Duplex (FD) Amplify-and-Forward (AF) relaying network is examined. A dual-hop relay system with one source, one destination and N FD AF relays is considered. Each FD relay is equipped with N,. antennas for receiving and N, antennas for transmitting. In this FD relay system, joint selection strategy involves choosing the best single relay and the best single receive/transmit antenna at the source-to-relay/relay-to-destination links. The system model is developped and the outage probability (OP) and the bit error rate (BER) of the system for different numbers of relay and antenna cases are examined in Rayleigh fading channel via Monte Carlo simulations.Dept Comp Engn & Elect & Elect Engn, Elect & Elect Engn, Bilkent Uni