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Health complications during the gestation period have evolved as a global issue. These complications sometimes result in the mortality of the fetus, which is more prevalent in developing and underdeveloped countries. The genesis of machine learning (ML) algorithms in the healthcare domain have brought remarkable progress in disease diagnosis, treatment, and prognosis. This research deploys various...
In the current IEEE 802.11 wireless LAN (WLAN), each station (STA) must obtain transmission opportunity (TXOP) on its primary channel. It means that current WLAN hardly utilizes the whole spectral resources in a frequency band if congestion occurs in some WLAN channels or bands. To overcome this problem, a concept of alternative primary channel (APCH) has been proposed. The APCH is a channel on which...
In this paper, we propose a low latency relay transmission scheme for WLAN which simultaneously uses multiple bands. In order to reduce the latency, the proposed relay transmission scheme forwards a bit sequence which is obtained by truncated decoding. In the proposed relay transmission scheme, a relay node receives a header of a frame on a frequency band. If relay transmission is required, the relay...
In this paper, we propose a synchronization scheme to obtain frequency diversity in a WLAN system which simultaneously uses the multiple bands such as 5 GHz, 2.4 GHz and 920 MHz simultaneously. The proposed scheme is to combine the output of correlators after compensation for the difference of the center frequency on each frequency band. The proposed scheme obtains a large frequency diversity gain...
The traffic from many smartphones in a bullet train is increasing and there is a fear of the capacity lack in the train-unit entrance circuit. In the Sequentially Switched Antenna Array Receiver, the array antenna elements fix the receiving point against the travel of the bullet train. In addition, it is necessary to synchronize the switching with the sampling period. We propose a multiple antenna...
A continuous-switching type array antenna receiver has been proposed in order to reduce the deterioration due to fast-fading channel variations and improve communication performance. The receive antennas are placed in a linear array, and by sequentially switching the elements in the opposite direction to the direction of the train travel, it has been possible to fix the signal receiving point virtually...
A sequentially switched antenna array receiver (SSAAR) has been developed in order to lessen the fast-fading effects on super-express trains. The array elements are switched in reverse sequence to the direction of the train motion. To demonstrate the performance improvements, measurements were made using a scale model train with receiver moving at 3.6 km/h. A software simulation based on the Worldwide...
A 60 GHz wireless communication system has been proposed as a replacement for data cables in a data-center cabinet in order to reduce the significant cooling energy costs. This paper investigates the feasibility of placing adaptive absorber-reflector regions on the sides of a cabinet as a static channel fading counter-measure and also to optimize performance for a particular server. As a result of...
The modified Luise and Reggiannini (L&R) algorithm is one of the frequency offset estimation algorithms suitable for use with the Digital Video Broadcasting — Satellite (DVB-S2) standard. Recently we demonstrated an enhanced poly-polarization multiplexing (EPPM) system incorporating L&R frequency recovery as a hardware prototype in order to evaluate its high spectral-efficiency in a real satellite...
A 12-element Electronically Steerable Parasitic Array Radiator (ESPAR) antenna system has been designed for direction-of-arrival (DoA) estimation as part of a railway control system. The DoA is estimated using the cross-correlation and MUSIC algorithms. Whilst a majority of reported DoA estimation systems typically operate in wideband WLAN or ISM band systems with a static condition, our narrowband...
The near Shannon capacity approaching low-density parity-check (LDPC) linear block codes are now in widespread use in modern systems including the long term evolution advanced (LTE-A) cellular, 802.11η Wi-Fi and DVB-S2 satellite communications standards. The decoders based on the iterative belief propagation algorithm provide near optimum performance but also have very high computational complexity...
We have recently implemented a poly-polarization multiplexing (PPM) system as a hardware prototype in order to demonstrate its high spectral-efficiency in a satellite channel. The Luise and Reggiannini (L&R) algorithm is one of the frequency offset estimation methods suitable for use with the Digital Video Broadcasting — Satellite (DVB-S2) standard, and has also been implemented in our PPM receiver...
Frequency recovery is a critical element in virtually all high data-rate communications systems, and in order to enhance the performance of our recently proposed poly-polarization multiplexing (PPM) satellite system, we have investigated the performance benefits of distributing the unique word (UW) symbols. The mean square error is calculated for different correlation based algorithms with increasing...
A poly-polarization multiplexing (PPM) scheme, that simultaneously utilizes two orthogonal polarization signals to create virtual additional planes, has been studied to enhance the spectrum efficiency for fixed satellite communication in the Ku band (12, 14 GHz). In this paper, to further increase the spectrum efficiency, we propose an enhanced PPM (E-PPM) scheme. By formulating the generalized linear...
In the case of broadband wireless access systems operating over non-line-of-sight (NLOS) links, the multipath can be severe. This leads to frequency-selective fading channel which causes distortions of the received signal. The single-carrier (SC) modulation method combined with frequency-domain equalization (FDE) at the receiver has been proposed as an alternative to the orthogonal frequency division...
A cooperative relay has been studied as a method to improve transmission quality in wireless mesh networks and cellular systems. Multiple antenna elements at a source node enable adaptive beamforming and thus improve total performance of relay transmission. In this paper, we propose simple transmit beamforming at a source node when the source node has two or more antenna elements and knows all channel...
Low-density parity-check (LDPC) codes are capacity approaching codes that have rapidly been adopted in modern systems such as the IEEE 802.11n and long term evolution advanced (LTE-A) communications standards. The decoders based on the iterative belief propagation offer exceedingly high performance but unfortunately have high computational complexity. Therefore significant research has focused on...
The interference between nearby links in a wireless multi-hop network degrades the area spectral efficiency. Thus there have been many works on a use of narrow beam antenna or adaptive array capable of forming nulls. Especially, the adaptive array allows simultaneous transmissions in multiple links within a limited area by suppressing the interference among those. However, efficient routing and scheduling...
Remarkably low error rates can be obtained using low-density parity-check (LDPC) codes and their use is now an increasingly common option in communications standards. The classic decoders based on belief propagation offer very high performance but have high implementation complexity. Therefore over the last decade simpler architectures such as the bit flipping class of algorithms have been researched...
Wireless relay is an essential technology to achieve a flexible network for ubiquitous communication. To improve throughput performance in the network, network coding (NC) has been proposed for a two-user relay node. NC is a concept encoding both users' data into one packet and multicasting it simultaneously. However, if the relay node has two or more antenna elements, antenna pattern control is additionally...
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