Near-field Magnetic Communication Research Articles

The Inter-channel Interference Cancellation Algorithm for Wireless Magnetic Induction MIMO Communication System Based on Zero-forcing Precoding

Abstract The wireless magnetic induction MIMO system can enhance the data transmission rate in near-field magnetic induction communication, but it also suffers from severe inter-channel interference issues. This paper introduces precoding techniques into the wireless magnetic induction MIMO system, employing the zero-forcing precoding algorithm to eliminate interference between different channels. Firstly, leveraging the characteristic that the channel state of magnetic induction transmit-receive coils is determined solely by the physical parameters of the coils, channel estimation is performed to obtain the channel gain matrix for wireless magnetic induction communication. Subsequently, the obtained channel matrix is subjected to zero-forcing precoding to eliminate interference caused by coupling between different channels. Simulation results indicate that the data transmission rate of the wireless magnetic induction MIMO system is significantly higher after applying zero-forcing precoding compared to the rate without it. Additionally, the system’s data transmission rate decreases as the distance between the transmitting and receiving coils increases.

Software and hardware applications for near-field magnetic communication systems design

Software and hardware applications for near-field magnetic communication systems design

ИССЛЕДОВАНИЕ ПОМЕХОВОГО ФОНА НА ВХОДЕ ПРИЕМНИКА СИСТЕМЫ БЛИЖНЕПОЛЬНОЙ МАГНИТНОЙ СВЯЗИ В ГОРОДСКИХ УСЛОВИЯХ

Near-field magnetic communication (NFMC) has unique characteristics, such as secrecy,communication channel security, the ability to pass a signal through the vast majority of obstacleswithout significant attenuation. NFMC can be used in such use cases where traditional radio isimpossible. One of the tasks in which the use of NFMC is relevant is to provide reliable wireless communication for rescuers, firefighters, employees of the Ministry of Emergency Situations whenperforming their professional activities in the conditions of blockages caused by various destructionsof urban buildings. It should be noted that under such conditions, the conductivity of buildingmaterials and soil can affect the propagation of not only electric, but also magnetic fields. The factis that due to the conductivity of such materials, when using radio coupling, eddy currents arise inthe materials, which leads to the appearance of a secondary magnetic field that is in antiphase.The system under consideration is not subject to the effects described above. This article presentsthe results of experimental studies aimed at studying the interference environment in the NFMCchannel. Field experiments were carried out to measure the interference environment. Based onthe data obtained, it was concluded that the use of NFMC systems in urban environments is a ratherdifficult task due to the nature of the interference propagating in the channel of this type ofcommunication. The effective use of NFMC requires the development of receiving devices thatprovide sufficiently strong filtering of signals outside the selected band. Narrow band and highorder filtering is key priority of observed communication system.

Frequency‐agile load‐modulated magnetic resonance wireless power transfer system for reliable near‐field in‐band signalling

A frequency-agile load modulation scheme is proposed for reliable near-field magnetic communication with a magnetic resonance wireless power transfer system. A working prototype of the system to realise concurrent power and data transfer in the high-frequency band has been fabricated to verify that demodulation of the load modulation signal state detected on the transmitter side is stable over the distance ranges covering the near-field coupling region. This scheme can be a simple and efficient solution against potential issues such as non-communication and envelope inversion arising from strong magnetic resonance coupling.

Multihop Relay Techniques for Communication Range Extension in Near-Field Magnetic Induction Communication Systems

munications and near field magnetic induction communication (NFMIC) is discussed. Three multihop relay strategies for NFMIC are proposed: Non Line of Sight Magnetic Induction Relay (NLoS-MI Relay), Non Line of Sight Master/Assistant Magnetic Induction Relay1 (NLoS-MAMI Relay1) and Non Line of Sight Master/Assistant Magnetic Induction Relay2 (NLoSMAMI Relay2). In the first approach only one node contributes to the communication, while in the other two techniques (which are based on a master-assistant strategy), two relaying nodes are employed. This paper shows that these three techniques can be used to overcome the problem of dead spots within a body area network and extend the communication range without increasing the transmission power and the antenna size or decreasing receiver sensitivity. The impact of the separation distance between the nodes on the achievable RSS and channel data rate is evaluated for the three techniques. It is demonstrated that the technique which is most effective depends on the specific network topology. Optimum selection of nodes as relay master and assistant based on the location of the nodes is discussed. The paper also studies the impact of the quality factor on achievable data rate. It is shown that to obtain the highest data rate, the optimum quality factor needs to be determined for each proposed cooperative communication method.

NFMIC Cooperative Communication Methods for Body Area Networks

To achieve higher data rate or to extend the coverage range of a wireless communication system, cooperative relay has been seen as a promising solution. This concept has been integrated in many traditional wireless communication networks. However, it has not been extensively examined for near field magnetic induction communication (NFMIC) systems. This paper aims to apply cooperative relay to NFMIC in a sense that is applicable to body area networking, since NFMIC is stated to be a suitable physical layer for body area networks. We have shown that using idle NFMIC nodes as relaying terminals, the system performance will be enhanced, as compared to a point to point communication system. In this context we have proposed three relaying methods to enhance the data rate and the received signal power in a personal area network. The relaying strategies are denoted as MI-Relay, MAMI Relay1 and MAMI Relay2. In this paper, using theoretical studies and simulation results, we have compared the performance of the three strategies and we have shown that higher data rates can be achieved through MAMI Relay1. However, we have discussed that the separation distance between relaying nodes and the source or destination can be a key factor for relay node selection.

One Tooth, Two Tooth, Green Tooth, Bluetooth, Part I

One Tooth, Two Tooth, Green Tooth, Bluetooth, Part I

Near-field magnetic communication

Even as cell phones have shrunk in size while boasting an ever-increasing array of features, two things about them haven't changed much: they still sprout a stubby antenna and, if you want a headset, you have to put up with an unwieldy wire connecting the headset and the phone. Thanks to a patented technology called near-field magnetic communication (NFMC), from Aura Communications, one can also cut the cord between the phone and the headset. While the concepts behind magnetic induction communication have been around for decades, Aura's engineers are the first to develop and implement practical solutions capturing the benefits of this technology. NFMC communicates wirelessly by coupling a very-low-power quasistatic magnetic field at 13.56 MHz. This paper discusses further the benefits of this technology.