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

IoT in Action: Design and Implementation of a Building Evacuation Service

With the development of sensor technologies, various application areas have emerged. The usage of these technologies and exploitation of recent improvements have clear benefits on building applications. Such use-cases can improve smart functions of buildings and can increase the end-user comfort. As a similar notion, building automation systems (BAS) are smart systems that target to provide automated management of various control services and to improve resource usage efficiency. However, buildings generally contain hardware and control services from a diverse set of characteristics. The automated and central management of such functions can be challenging. In order to overcome such issues, an Emergency Evacuation Service is proposed for BAS, where requirements of such central management model are analyzed and model content and subservice definitions are prepared. A crucial scenario, which could be a necessity for future BAS, is defined and an approach for evacuation of people in the buildings at emergency situations is proposed. For real-life scenarios, the Evacuation Service is implemented by using a low-cost design, which is appropriate for Internet of Things (IoT) based BAS applications. As demonstrated, the proposed service model can provide effective performance in real-life deployments

Novel Tone Reservation Method for DFT-s-OFDM

In this paper, a novel guard-tone reservation (GTR) method is proposed to reduce the peak-to-average power ratio (PAPR) of discrete Fourier transform-spread-orthogonal frequency-division multiplexing (DFT-s-OFDM) waveform. Unlike existing PAPR reduction methods, the proposed GTR operates directly in the data symbol domain, estimating the peaks through the relations between the data symbols, while the corresponding peak-cancellation signal (PCS) is efficiently embedded into the waveform processing. Furthermore, the PCS is generated by exploiting only the guard-band tones, leaving thus the inband data tones undistorted. The performance of the method is evaluated in 5G New Radio (NR) uplink context including also realistic measured power amplifier (PA) characteristics. The obtained results show that significant PAPR reduction and corresponding PA output power gains can be obtained while the computational complexity is shown to be low.publishedVersionPeer reviewe