Bidirectional Full-duplex Communication Research Articles

Multi-Stream Transmission in Massive MIMO Systems With Full-Duplex Bi-Directional Communication Links

This paper considers a full-duplex (FD) multi-user massive multiple-input multiple-output system where the base station (BS) and user equipment (UE) bi-directionally transmit and receive multiple independent data streams over the same frequency band. The BS and UEs are equipped with a large-scale antenna array. Accounting for imperfect channel state information, we derive the closed-form expressions for the achievable sum-rate and sum spectral efficiency (SE) for the proposed model using maximum-ratio combining and zero-forcing detection. The analytical solutions are verified with simulations. In addition, our analytical results highlight the benefits of multi-stream transmission and show an improved SE for fewer UEs. Moreover, the results show that increasing the antenna array size helps combat self-interference.

Intelligent-Reflecting-Surface-Aided Bidirectional Full-Duplex Communication System With Imperfect Self-Interference Cancellation and Hardware Impairments

In this article, we combine two new technologies [full-duplex (FD) transmission and intelligent reflecting surface (IRS)] in a wireless communication system for investigation. Specifically, we evaluate the performance of an IRS-aided bidirectional FD communication system in a practical scenario where imperfect self-interference (SI) cancellation and hardware impairments (HIs) are taken into consideration. We successfully derive the closed-form expressions of ergodic capacity (EC) and symbol error rate (SER) of the IRS-aided FD-HI system over Rayleigh fading channels. We confirm the correctness of the derived expressions via Monte-Carlo simulations. To clarify the effects of residual SI and HIs, we compare the performance of the IRS-aided FD-HI system with that of the IRS-aided FD-ideal hardware (ID), half-duplex (HD)-HI, and HD-ID systems. Numerical results clarify a strong impact of residual SI and HIs on the EC and SER of the IRS-aided FD-HI system. Thus, the EC and SER of the IRS-aided FD-HI system go to the saturated values in a high signal-to-noise regime even with a large number of reflecting elements in the IRS. Therefore, depending on the residual SI and HI levels as well as the requirements about the EC and SER in practice, we can use appropriately the transmit power of terminals and number of reflecting elements in the IRS for enhancing the performance and saving the energy consumption of the IRS-aided FD-HI system.

Photonics millimeter wave bidirectional full-duplex communication based on polarization multiplexing.

We have proposed and experimentally implemented a photonics-aided large-capacity long-distance mm-wave bidirectional full-duplex communication system at the W-band based on polarization multiplexing. The same radio frequency (RF) carrier source is shared by both the uplink and the downlink, and a pair of orthomode transducers (OMTs) are used to separate the dual orthogonally polarized channels. To achieve the maximum spectrum efficiency and throughput, 10-Gbaud probabilistically shaped 256-level quadrature-amplitude-modulation (PS-256QAM) signals with 7.07 bit/symbol/Hz are transmitted in Ch. H and Ch. V. The system can support the bidirectional transmission with 103-Gbps data rate over 4600-m RF wireless distance. To the best of our knowledge, based on a photonics-aided bidirectional full-duplex system, this is the first time to realize a record-breaking bit rate-distance product at the W-band, i.e., 103 Gbps × 4.6 km = 473.8 Gbps•km.

A Self Interference Nulling Filter Using Effective Channel Information for Full Duplex Systems

We propose a spatial domain interference cancelation scheme for full duplex bi-directional communication systems. Although the conventional pre-processing filters, such as null space projection and minimum mean square error (MMSE), can eliminate self interference, they require the spatial dimensions more than the number of receive antennas. However, proposed scheme requires only one spatial dimension regardless of the number of receive antennas, which enables more efficient antenna allocation. Simulation results show that proposed scheme obtains higher achievable rate than the half duplex system and the MMSE filter.

Secrecy Energy Efficiency of MIMOME Wiretap Channels With Full-Duplex Jamming

Full-duplex (FD) jamming transceivers recently have been shown to enhance the information security of wireless communication systems by simultaneously transmitting artificial noise (AN) while receiving information. In this paper, we investigate whether FD jamming can also improve the system’s secrecy energy efficiency (SEE) in terms of securely communicated bits per Joule when considering the additional power used for jamming and self-interference (SI) cancellation. Moreover, the degrading effect of the residual SI is also taken into account. In this regard, we formulate a set of SEE maximization problems for a FD multiple-input-multiple-output multiple-antenna eavesdropper (MIMOME) wiretap channel, considering both cases where exact or statistical channel state information (CSI) is available. Due to the intractable problem structure, we propose iterative solutions in each case with a proven convergence to a stationary point. Numerical simulations indicate only a marginal SEE gain, through the utilization of FD jamming, for a wide range of system conditions. However, when SI can efficiently be mitigated, the observed gain is considerable for scenarios with a small distance between the FD node and the eavesdropper, a high signal-to-noise ratio (SNR), or for a bidirectional FD communication setup.

Achievable Rates of Full-Duplex MIMO Radios in Fast Fading Channels With Imperfect Channel Estimation

We study the theoretical performance of two full-duplex multiple-input multiple-output (MIMO) radio systems: a full-duplex bi-directional communication system and a full-duplex relay system. We focus on the effect of a (digitally manageable) residual self-interference due to imperfect channel estimation (with independent and identically distributed (i.i.d.) Gaussian channel estimation error) and transmitter noise. We assume that the instantaneous channel state information (CSI) is not available the transmitters. To maximize the system ergodic mutual information, which is a nonconvex function of power allocation vectors at the nodes, a gradient projection algorithm is developed to optimize the power allocation vectors. This algorithm exploits both spatial and temporal freedoms of the source covariance matrices of the MIMO links between transmitters and receivers to achieve higher sum ergodic mutual information. It is observed through simulations that the full-duplex mode is optimal when the nominal self-interference is low, and the half-duplex mode is optimal when the nominal self-interference is high. In addition to an exact closed-form ergodic mutual information expression, we introduce a much simpler asymptotic closed-form ergodic mutual information expression, which in turn simplifies the computation of the power allocation vectors.

Full-Duplex Bidirectional MIMO: Achievable Rates Under Limited Dynamic Range

In this paper, we consider the problem of full-duplex bidirectional communication between a pair of modems, each with multiple transmit and receive antennas. The principal difficulty in implementing such a system is that, due to the close proximity of each modem's transmit antennas to its receive antennas, each modem's outgoing signal can exceed the dynamic range of its input circuitry, making it difficult-if not impossible-to recover the desired incoming signal. To address these challenges, we consider systems that use pilot-aided channel estimates to perform transmit beamforming, receive beamforming, and interference cancellation. Modeling transmitter/receiver dynamic-range limitations explicitly, we derive tight upper and lower bounds on the achievable sum-rate, and propose a transmission scheme based on maximization of the lower bound, which requires us to (numerically) solve a nonconvex optimization problem. In addition, we derive an analytic approximation to the achievable sum-rate, and show, numerically, that it is quite accurate. We then study the behavior of the sum-rate as a function of signal-to-noise ratio, interference-to-noise ratio, transmitter/receiver dynamic range, number of antennas, and training length, using optimized half-duplex signaling as a baseline.

Bluetooth Transceivers for Full Duplex Communications in Mobile Robots

Projek ini mengeksplotasi penggunaan Teknologi Bluetooth dalam robot mudah alih. Robot mudah alih mempunyai kebolehan untuk bergerak secara automasi menggunakan algoritma yang rumit dan canggih. Algoritma disimpan dalam sebuah komputer sebagai tuan dan juga “server”. Segala bacaan penderia daripada robot mudah alih akan dihantar kepada tuan dan diproses. Kemudian, arahan untuk langkah seterusnya akan dihantar dari “server” kepada robot mudah alih dalam mode komunikasi dua hala dan dupleks penuh. Maka, “otak” utama berada di "server" dan bukannya pada robot mudah alih. Kertas ini akan memfokus pada perantaraan muka antara Bluetooth transceiver dan Handy Board MC68HC11 mikro pengawal pada robot mudah alih. Untuk kes biasa, satu penerima dan penghantar diperlukan untuk setiap alat (server dan client) masing-masing, tetapi dengan Teknologi Bluetooth, hanya dua Bluetooth transceiver diperlukan untuk mencapai perhubungan dupleks penuh. Projek ini telah menghasilkan robot mudah alih dengan kebolehan Bluetooth. Robot tersebut boleh dikawal secara “wirelessly” melalui Bluetooth transceiver. Kata kunci: Teknologi Bluetooth; dua hala; duplex penuh; automasi; Handy Board This work explores the implementation of Bluetooth technology in mobile robots. The mobile robot has the capability to move around autonomously using complicated and powerful algorithm. The algorithms are stored in the master as the server. All sensor readings from the mobile robot will be transmitted to the master and processed. Then, command or instruction for further action is transmitted from the server to the mobile robot in a bi-directional full duplex communication mode. Hence, the main “brain” is in the server instead of the mobile robot. This paper will focus on the interfacing between Bluetooth tranceiver and Handy Board MC68HC11 micro-controller of mobile robot. For common case, a receiver and transmitter are needed for each device (robot and control unit), but with Bluetooth technology, only two Bluetooth transceivers are needed to achieve full duplex connection. This project has provided a Bluetooth enabled mobile robot. The mobile robot can be controled wirelessly via Bluetooth transceiver. Key words: Bluetooth Technology; bi-directional; full duplex; autonomously; Handy Board

Improvement of Signal Integrity in Transcutaneous Optical Full Duplex Bidirectional Communication System with Same Near Infrared Wavelength Using Optical Polarizer

Improvement of Signal Integrity in Transcutaneous Optical Full Duplex Bidirectional Communication System with Same Near Infrared Wavelength Using Optical Polarizer

First demonstration of native Ethernet optical transport system prototype at 10 Gb/s based on multiplexing of gigabit Ethernet signals

The first system to transport native Ethernet data at a serial rate of 10 Gb/s is reported. Up to 8 asynchronous gigabit Ethernet signals are multiplexed to 10 Gb/s and directly modulate a Fabry-Perot laser at 1310 nm for 2-8 km transport over standard single-mode fiber bidirectional full-duplex communication between individual gigabit Ethernet hosts is demonstrated. System operation is entirely based on the physical layer signaling standards for gigabit Ethernet. Solutions to unique Ethernet synchronization and control problems are presented, and novel differences between multiplexed 8b/10b data and pseudorandom bit sequences are shown. Optical link performance and packet loss rates are presented.