PHY5 – Communication and networking

Thursday, 9 June 2022, 16:00-17:30, Room A304

Session Chair: Adrian Agustin (Centre Tecnològic de Telecomunicacions de Catalunya (CTTC/iCERCA), ES)

Low-Subpacketization Multi-Antenna Coded Caching for Dynamic Networks

MohammadJavad Salehi (University of Oulu, Finland); Emanuele Parrinello (EURECOM, France); Hamidreza Bakhshzad Mahmoodi and Antti Tölli (University of Oulu, Finland)
Multi-antenna coded caching combines a global caching gain, proportional to the total cache size in the network, with an additional spatial multiplexing gain that stems from multiple transmitting antennas. However, classic centralized coded caching schemes are not suitable for dynamic networks as they require prior knowledge of the number of users to indicate what data should be cached at each user during the placement phase. On the other hand, fully decentralized schemes provide comparable gains to their centralized counterparts only when the number of users is very large. In this paper, we propose a novel multi-antenna coded caching scheme for dynamic networks, where instead of defining individual cache contents, we associate users with a limited set of predefined caching profiles. Then, during the delivery phase, we aim at achieving a combined caching and spatial multiplexing gain, comparable to a large extent with the ideal case of fully centralized schemes. The resulting scheme imposes small subpacketization and beamforming overheads, is robust under dynamic network conditions, and incurs small finite-SNR performance loss compared with centralized schemes.

Incorporation of Confidence Interval into Rate Selection Based on the Extreme Value Theory for Ultra-Reliable Communications

Niloofar Mehrnia (Koc University Ford Otosan Automotive Technologies Laboratory (KUFOTAL), Turkey); Sinem Coleri (Koc University, Turkey)
Proper determination of the transmission rate in ultra-reliable low latency communication (URLLC) needs to incorporate a confidence interval (CI) for the estimated parameters due to the large amount of data required for their accurate estimation. In this paper, we propose a framework based on the extreme value theory (EVT) for determining the transmission rate along with its corresponding CI for an ultra-reliable communication system. This framework consists of characterizing the statistics of extreme events by fitting the generalized Pareto distribution (GPD) to the channel tail, deriving the GPD parameters and their associated CIs, and obtaining the transmission rate within a confidence interval.
Based on the data collected within the engine compartment of Fiat Linea, we demonstrate the accuracy of the estimated rate obtained through the EVT-based framework considering the confidence interval for the GPD parameters. Additionally, we show that proper estimation of the transmission rate based on the proposed framework requires a lower number of samples compared to the traditional extrapolation-based approaches.

Random Access Networks with Spatial Reuse

Adrian Agustin (Centre Tecnològic de Telecomunicacions de Catalunya (CTTC/iCERCA), Spain); Adriano Pastore and Monica Navarro (Centre Tecnològic de Telecomunicacions de Catalunya (CTTC), Spain)
Providing ultra-reliable, low-latency and massive access is a technical challenge that demands a redesign of current Media Access Control (MAC) layer in wireless cellular networks. This work focuses on studying the conventional slotted ALOHA protocol and ways to improve its efficiency with the objective of providing a solution to the massive access of terminals. In particular, we concentrate on the case where multiple neighboring
cells use the same resources, so that the system operates under inter-cell interference. While in conventional slotted ALOHA, terminals transmit with a fixed probability, in our scenario we propose instead to exploit channel-state information at terminals so as to define (minimum) signal-to-noise and (maximum) interference conditions, under which a terminal is allowed to transmit. We conduct a theoretical analysis for a simple scenario with Rayleigh fading where the system throughput is shown to scale linearly with the number of coexisting cells and in logarithmic scale with the number of terminals per cell.

Probabilistic Amplitude Shaping to Enhance ARoF Fronthaul Capacity for Mm-Wave 5G/6G Systems

Javier Perez Santacruz and Simon Rommel (Eindhoven University of Technology, The Netherlands); Antonio Jurado Navas (University of Málaga, Spain); Idelfonso Tafur Monroy (Eindhoven University of Technology, The Netherlands)
Analog radio-over-fiber (ARoF) technology has proven to be a promising solution to be part of the future millimeter-wave (mm-wave) 5G/6G architecture due to its attractive benefits such as simplified remote antenna units (RAUs), low-power consumption, and low cost. However, ARoF channels present hefty drawbacks that need to be addressed. The probabilistic amplitude shaping (PAS) technique is able to reduce the impact of such drawbacks, allowing a fine optimization of channel capacity. In particular, enumerative sphere shaping (ESS) implementation stands out as an excellent PAS approach because of its energy-efficiency and low complexity for short blocklengths. In this work, for the first time to the best of our knowledge, an ESS scheme is evaluated in an experimental bidirectional mm-wave ARoF setup oriented towards 5G communications. Furthermore, a novel soft ESS demapping algorithm is proposed and explained. The experimental results confirm the ESS technique, together with the proposed algorithm, as a convenient solution to enhance the channel capacity of mm-wave ARoF systems for 5G/6G fronthaul.

Mobility’s Influence on System Loss in Off-Body BAN Scenarios

Manuel Ferreira (ESTSetúbal/Polytechnic Institute of Setúbal, Portugal); Filipe Cardoso (ESTSetubal/Polytechnic Institute of Setubal and INESC-ID, Portugal); Sławomir J. Ambroziak (Gdańsk University of Technology, Poland); Kenan Turbic (RWTH Aachen University, Germany); Luis M. Correia (IST/INESC-ID – University of Lisbon & INESC, Portugal)
In this paper, a measurement campaign for off-body communications in an indoor environment is investigated for a set of on-body antennas. The channel impulse response was measured with the user approaching and departing from an off-body fixed antenna using two user dynamics, standing at fixed positions and walking. The processing of the measurement data allowed to evaluate system loss statistics. Different antenna configurations are classified in terms of mobility and visibility depending on the on-body antenna placement. A dependence on distance is found for the antennas with the lowest mobility (chest and head), while no significant dependence is found for the antennas with the highest mobility (arms and legs). Regarding the standard deviation of system loss, higher values are found in walking scenarios (above 2.6 dB) compared to the standing ones (below 0.6 dB); standard deviation also shows a clear dependence on mobility, 1.6 dB for walking and 0.5 dB for standing scenarios.

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