PHY7 – Beyond 5G (1)

Thursday, 8 June 2023, 11:00-12:30, Room J1

Session Chair: Volker Ziegler (Nokia Bell Labs & CTO, Germany)

Doppler-Resilient Universal Filtered MultiCarrier (DR-UFMC): A Beyond-OTFS Modulation
Carmen D’Andrea (Università di Cassino e del Lazio Meridionale, Italy & Consorzio Nazionale Interuniversitario per Le Telecomunicazioni (CNIT), Italy); Stefano Buzzi (University of Cassino and Lazio Meridionale/CNIT, Italy); Maria Fresia and Xiaofeng Wu (Huawei Technol. Duesseldorf GmbH, Germany)
In the past few years, some alternatives to the Orthogonal Frequency Division Multiplexing (OFDM) modulation have been considered to improve its spectral containment and its performance level in the presence of heavy Doppler shifts. This paper examines a novel modulation, named Doppler-Resilient Universal Filtered MultiCarrier (DR-UFMC), which has the objective of combining the advantages provided by the Universal Filtered MultiCarrier (UFMC) modulation (i.e., better spectral containment), with those of the Orthogonal Time Frequency Space (OTFS) modulation (i.e., better performance in timevarying environments). The paper contains the mathematical model and detailed transceiver block scheme of the newly described modulation, along with a numerical analysis contrasting DR-UFMC against OTFS, OFDM with one-tap frequency domain equalization (FDE), and OFDM with multicarrier multisymbol linear MMSE processing. Results clearly show the superiority, with respect to the cited benchmarks, of the newly proposed modulation in terms of achievable spectral efficiency. Interestingly, it is also seen that OFDM, when considered in conjunction with multicarrier multisymbol linear minimum mean squares error (MMSE) processing, performs slightly better than OTFS in terms of achievable spectral efficiency.

Predictive Resource Allocation for URLLC Using Empirical Mode Decomposition
Chandu Subhash Madhusanka Wijenayake Jayawardhana, Sivalingam Thushan, Nurul Huda Mahmood, Nandana Rajatheva and Matti Latva-aho (University of Oulu, Finland)
Effective resource allocation is a crucial requirement to achieve the stringent performance targets of ultra-reliable low-latency communication (URLLC) services. Predicting future interference and utilizing it to design efficient interference management algorithms is one way to allocate resources for URLLC services effectively. This paper proposes an empirical mode decomposition (EMD) based hybrid prediction method to predict the interference and allocate resources for downlink based on the prediction results. EMD is used to decompose the past interference values faced by the user equipment. Long shortterm memory and auto-regressive integrated moving average methods are used to predict the decomposed components. The final predicted interference value is reconstructed using individual predicted values of decomposed components. It is found that such a decomposition-based prediction method reduces the root mean squared error of the prediction by 20 − 25%. The proposed resource allocation algorithm utilizing the EMD-based interference prediction was found to meet near-optimal allocation of resources and correspondingly results in 2 − 3 orders of magnitude lower outage compared to state-of-the-art baseline prediction algorithm-based resource allocation.

Waveforms for Sub-THz 6G: Design Guidelines
Muris Sarajlic (Ericsson AB, Lund, Sweden); Nuutti Tervo and Aarno Pärssinen (University of Oulu, Finland); Hardy Halbauer (Nokia Bell Labs, Germany); Kilian Roth (Intel, Germany); Vaidyanathan Kumar and Tommy Svensson (Chalmers University of Technology, Sweden); Ahmad Nimr (Technische Universität Dresden, Germany); Stephan Zeitz and Meik Dörpinghaus (TU Dresden, Germany); Gerhard P. Fettweis (Technische Universität Dresden, Germany); Le-Hang Nguyen (Bell Labs, Nokia, Germany)
The projected sub-THz (100 – 300 GHz) part of the upcoming 6G standard will require a careful design of the waveform and choice of slot structure. Not only that the design of the physical layer for 6G will be driven by ambitious system performance requirements, but also hardware limitations, specific to sub-THz frequencies, pose a fundamental design constraint for the waveform. In this contribution, general guidelines for the waveform design are given, together with a non-exhaustive list of exemplary waveforms that can be used to meet the design requirements.

An Analysis with Interplay of NOMA and RSMA for RIS-Aided System
Farjam Karim (Taiwan); Nurul Huda Mahmood (University of Oulu, Finland)
Reconfigurable intelligent surface (RIS) has emerged as a potential technology for future-generation wireless communication by enhancing its signal quality and providing broader coverage network area. In this work, we provide an analytical framework of a RIS-assisted multi-user downlink system where the base station (BS) transmits a superimposed signal to multiple users with the aid of a RIS using nonorthogonal multiple access (NOMA) and rate splitting multiple access (RSMA) transmission technique. First, we discuss the statistical characteristics and evaluate the probability density function (PDF) of the different channels involved in the transmission. We then evaluate the system performance utilizing the PDF and obtain the analytical expressions of the outage probability through the application of NOMA and RSMA transmission techniques and verify the preciseness of the derived closed-form expressions using Monte-Carlo (MC) simulations. Moreover, to gain some useful insights about the system, we also highlight the impact of transmit power availability at the BS, imperfect channel state information (CSI) on the outage probability of each user, effect of number of RIS elements on outage probability. Lastly, we demonstrate the superiority of RSMA over NOMA on the performance of the system.

Distributed MIMO Systems for 6G
Omer Haliloglu (Ericsson Research, Turkey); Han Yu, Charitha Madapatha and Hao Guo (Chalmers University of Technology, Sweden); Fehmi Emre Kadan (Ericsson Research, Turkey); Andreas Wolfgang (Qamcom Research & Technology AB, Sweden); Rafael Puerta (Ericsson & KTH Royal Institute of Technology, Sweden); Pål Frenger (Ericsson Research, Ericsson AB, Sweden); Tommy Svensson (Chalmers University of Technology, Sweden)
This study focuses on Distributed MIMO (D-MIMO) systems and provides a discussion about their role in next generation networks. The paradigm shift to distributed networks offers great potential to address the 6G requirements, through macro diversity. As 6G scenarios and use cases continue to emerge, new challenges are likely to arise that may affect the widespread implementation of D-MIMO. To address those, different deployment options have been proposed for roll-out considerations. They are composed of several sub-components that can be categorized as (i) wireless or wired fronthaul/backhaul, (ii) analog or digital signals, (iii) distributed or centralized processing, and (iv) coherent or non-coherent transmission. To facilitate standardization efforts, we provide 3GPP-aligned terminology for network nodes, multipoint transmission and reception schemes. In order to enable large-scale implementation of D-MIMO systems, it is important to determine the needed amount of distribution, develop practical solutions for high-frequency bands, and ways to convey data that meet the transport requirements. On this regard, we discuss key enablers and present simulation results for D-MIMO systems towards 6G. In particular, we present solutions for D-MIMO networks in dynamic scenarios related to channel estimation and layer-1 mobility considering coherent and non-coherent joint transmission, and analog fronthaul implementation using analogradio-over-fiber that are promising for high (upper mm-Wave and (sub-)THz) carrier frequencies, as well as integrated access and backhaul, network-controlled repeaters, and reconfigurable intelligent surfaces that are possible enablers for cost-efficient network densification at both low (cm-Wave, lower mm-Wave) and high carrier frequencies.

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