Convergent Communication, Sensing and Localization in 6G Systems: An Overview of Technologies, Opportunities and Challenges

Herein, we focus on convergent 6G communication, localization and sensing systems by identifying key technology enablers, discussing their underlying challenges, implementation issues, and recommending potential solutions. Moreover, we discuss exciting new opportunities for integrated localization and sensing applications, which will disrupt traditional design principles and revolutionize the way we live, interact with our environment, and do business. Regarding potential enabling technologies, 6G will continue to develop towards even higher frequency ranges, wider bandwidths, and massive antenna arrays. In turn, this will enable sensing solutions with very fine range, Doppler, and angular resolutions, as well as localization to cm-level degree of accuracy. Besides, new materials, device types, and reconfigurable surfaces will allow network operators to reshape and control the electromagnetic response of the environment. At the same time, machine learning and artificial intelligence will leverage the unprecedented availability of data and computing resources to tackle the biggest and hardest problems in wireless communication systems. As a result, 6G will be truly intelligent wireless systems that will provide not only ubiquitous communication but also empower high accuracy localization and high-resolution sensing services. They will become the catalyst for this revolution by bringing about a unique new set of features and service capabilities, where localization and sensing will coexist with communication, continuously sharing the available resources in time, frequency, and space. This work concludes by highlighting foundational research challenges, as well as implications and opportunities related to privacy, security, and trust

An FPGA-based accelerator for analog VLSI artificial neural network emulation

Analog VLSI circuits are being used successfully to implement Artificial Neural Networks (ANNs). These analog circuits exhibit nonlinear transfer function characteristics and suffer from device mismatches, degrading network performance. Because of the high cost involved with analog VLSI production, it is beneficial to predict implementation performance during design. We present an FPGA-based accelerator for the emulation of large (500+ synapses, 10k+ test samples) single-neuron ANNs implemented in analog VLSI. We used hardware time-multiplexing to scale network size and maximize hardware usage. An on-chip CPU controls the data flow through various memory systems to allow for large test sequences. We show that Block-RAM availability is the main implementation bottleneck and that a trade-off arises between emulation speed and hardware resources. However, we can emulate large amounts of synapses on an FPGA with limited resources. We have obtained a speedup of 30.5 times with respect to an optimized software implementation on a desktop computer

Real-Time RF Self-Interference Cancellation for In-Band Full Duplex

© 2015 IEEE. We demonstrate a real-time RF self-interference cancellation scheme for in-band full duplex using an electrical balance duplexer. The balance network in the duplexer has four 8-bit tunable capacitor banks, creating a four dimensional optimization space with over 4 billion settings. We present a particle swarm optimizer that is able to find a close to optimal solution within 1 ms. The goal of this demo is to show a self-interference cancellation scheme for very dynamic environments. More specifically our demo is able to mitigate instantaneous changes in the antenna impedance in order to keep the self-interference below the threshold.status: publishe

An Energy-Scalable In-Band Full Duplex Architecture

In-band full duplex (IBFD) is a promising technique that allows to potentially double the achievable bi-directional throughput over a given bandwidth. Moreover, it has been estimated that IBFD-equipped wireless networks can be more energy-efficient than half duplex ones due to the reduced energy cost of packet collisions. However, one key challenge for implementing an energy-efficient IBFD system is the cancellation of the interference produced by the transmitted signal. In fact, existing self-interference cancellation (SIC) techniques are not always energy-efficient, as the effect of the interference reduction might not be able to compensate the additional electronic power consumption introduced by the SIC module. Following this rationale, in this paper we propose and energy-efficient IBFD architecture that adapts the SIC module to the link conditions. By studying a symmetric bi-directional full duplex link, we show that the proposed architecture obtains significant energy savings by using a simple SIC scheme for short-range transmissions. More powerful SIC techniques are shown to be an energy-optimal choice only when transmitting over long link distances.status: publishe

Doppler Radar with In-Band Full Duplex Radios

status: publishe

Adaptive filter design for simultaneous in-band full-duplex communication and radar

The in-band full-duplex (IBFD) wirelesscommunication can achieve not only appreciable throughputgain but also is a key technology to enable concurrent radar andcommunication by one hardware. In such a system, an analogself-interference (SI) canceller is essential so that the receivedsignal can be processed digitally to achieve sufficient SNRfor IBFD communication. Unlike the previous similar workswhich rely on a classical matched filter, this paper derives therange-Doppler profile from the state of an adaptive filter, whichprimarily is applied to cancel the residual SI. Using standardIEEE 802.11ac signal, the proposed waveform-independenttechnique in this paper is simulated in a multi-target IBFDscenario. Furthermore, we employed a proof of concept setup tovalidate the proposed approach. The simulation and experimentalresults confirm that our method can render accurate rangeand velocity detection, and potentially satisfies a wide spectrumof opportunistic wireless sensing applications, ranging fromhand/body gesture detection to tracking and localization.info:eu-repo/semantics/publishe

Joint in-band full-duplex communication and radar processing

In-band full-duplex (IBFD) technology has the potential to not only double the communication throughput but also enable additional capabilities. The fusion of radar and communication subsystems is an excellent example of how IBFD facilitates integration of radar functionality into a communication system. Developing and analysis of a joint IBFD radar-communication (RadCom) system is at the core of this article. This system derives the range-Doppler image from the state of an adaptive filter, which already exists in a typical IBFD transceiver. Our approach is waveform-independent and reuses the radio frequency (RF) front-end while it requires little additional digital logic. The proposed system is prototyped to assess the modem-radar coexistence in a real-world IBFD communication link budget. Employing the prototyped system, we quantify the additional required logic resources and investigate whether such a RadCom approach dictates a tradeoff between the two intended functionalities. The experimental results show that the proposed solution enables a communication system to detect targets within 20 m while maintaining an IBFD link with another communication nodeinfo:eu-repo/semantics/publishe

Adaptive Filter Design for Simultaneous In-Band Full-Duplex Communication and Radar

status: accepte

Towards Instantaneous Collision and Interference Detection using In-Band Full Duplex

Wireless devices are ubiquitous nowadays and, since most of them use the same unlicensed frequency bands, the high number of packet losses due to interference and collisions degrade performance. Reliability, energy consumption, and latency are key challenges for future dense networks. Allowing the transmitter to take action, i.e., vacating the channel, as soon as a collision or interference is detected is crucial in improving these metrics. In-band full duplex radios enable the transmitter to simultaneously transmit packets and sense the spectrum for collisions and interference. This paper studies two important questions regarding transmitter-based collision and interference detection: (1) from an overall system perspective, does such detection outperform receiver-based detection and (2) which test statistic is the most accurate and sensitive at detecting collisions and interference. First, NS-3 simulations are used to show that transmitter-based detection reduces the energy consumption while improving the throughput in a typical star topology network. Next, we present a measurement-based study of four different techniques for transmitter-based collision and interference detection. In particular, we compare the energy detector with three goodness-of-fit tests in terms of probability of detection and false alarm. Our analysis shows that transmitterbased detection can detect between 80% to 100% of the collisions and interference occurring at the receiver, depending on the distance between the transmitter and the receiver. Of those detectable by the transmitter, our measurement results show that goodness-of-fit tests can detect nearly 100% of the collisions and have at least 10 dB better sensitivity as compared to the commonly proposed energy detection test. In general, the proposed techniques can detect interfering signals that are up to 25 dB below the remaining self-interference power.status: publishe

An In-B and Full-Duplex Transceiver for Simultaneous Communication and Environmental Sensing

status: publishe