scholarly journals Enhancing the Performance of Medical Implant Communication Systems through Cooperative Diversity

2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
Barnabás Hegyi ◽  
János Levendovszky
Keyword(s):  
Cooperative Communication ◽  
System Performance ◽  
Communication Systems ◽  
Communication Channel ◽  
Cooperative Diversity ◽  
Communication Link ◽  
Medical Implants ◽  
Medical Implant ◽  
Cardioverter Defibrillators ◽  
Implant Communication

Battery-operated medical implants—such as pacemakers or cardioverter-defibrillators—have already been widely used in practical telemedicine and telecare applications. However, no solution has yet been found to mitigate the effect of the fading that the in-body to off-body communication channel is subject to. In this paper, we reveal and assess the potential of cooperative diversity to combat fading—hence to improve system performance—in medical implant communication systems. In the particular cooperative communication scenario we consider, multiple cooperating receiver units are installed across the room accommodating the patient with a medical implant inside his/her body. Our investigations have shown that the application of cooperative diversity is a promising approach to enhance the performance of medical implant communication systems in various aspects such as implant lifetime and communication link reliability.

scholarly journals Analyzing bit error rate of relay sensors selection in wireless cooperative communication systems

2021 ◽  
Vol 10 (1) ◽  
pp. 216-223
Author(s):  
Ahmed Allawy Alawady ◽  
Ahmed Alkhayyat ◽  
Mohammed Ahmed Jubair ◽  
Mustafa Hamid Hassan ◽  
Salama A. Mostafa
Keyword(s):  
Cooperative Communication ◽  
System Performance ◽  
Communication Systems ◽  
Relay Selection ◽  
Relay Node ◽  
Cooperative Systems ◽  
Diversity Order ◽  
Channel Fading ◽  
Negative Effects ◽  
Relay Nodes

Cooperative communication systems, which make use of the intermediate relays between the transmitter and the receiver, have been employed as an effective technique to combat the channel fading and to enhance system performance. Cooperative systems have some drawbacks such as high latency and may diversity order not guaranteed. To alleviate the negative effects of these factors, the relay selection protocol is employed in cooperative communication systems to increase overall cooperative system performance. Relay selection in the cooperative systems enables the source to cooperate with the single relay node rather than multiple relay nodes which guaranteed the diversity order.

scholarly journals EMR: A new metric to assess the resilience of directional mmWave channels to blockages

2021 ◽  
Vol 2 (2) ◽  
pp. 47-60
Author(s):  
Fatih Erden ◽  
Ozgur Ozdemir ◽  
Ismail Guvenc ◽  
David W. Matolak
Keyword(s):  
Communication Systems ◽  
Communication Channel ◽  
Path Loss ◽  
Spatial Diversity ◽  
Line Of Sight ◽  
Communication Link ◽  
Weighted Sum ◽  
Channel Measurements ◽  
Angular Domain ◽  
Cosine Distance

Millimeter-wave (mmWave) communication systems require narrow beams to compensate for high path loss and to increase the communication range. If an obstacle blocks the dominant communication direction, alternative paths (directions) should be quickly identified to maintain reliable connectivity. In this paper, we introduce a new metric to quantify the Effective Multipath Richness (EMR) of a directional communication channel in the angular domain. In particular, the proposed metric takes into account the strength and spatial diversity of the resolved Multipath Components (MPCs), while also considering the beamwidth of the communication link and the blockage characteristics. The metric is defined as a weighted sum of the number of distinct MPC clusters in the angular domain, where the clustering of the MPCs is performed based on the cosine-distance between the dominant MPCs. For a given transmitter (TX) and receiver (RX) pair, the EMR is a single scalar value that characterizes the robustness of the communication link against blockages, as it captures the number of unique communication directions that can be utilized. It is also possible to characterize the blockage robustness for the whole environment by evaluating the spatial distribution of the EMR metric considering various different TX/RX locations. Using our proposed metric, one can assess the scattering richness of different environments to achieve a particular service quality. We evaluate the proposed metric using our 28 GHz channel measurements in a library environment for Line-of-Sight (LOS) and NLOS scenarios, and compare it with some other commonly used propagation metrics. We argue that EMR is especially informative at higher frequencies, e.g., mmWave and terahertz (THz), where the propagation attenuation is high, and directional Non-Light-of-Sight (NLOS) communication is critical for the success of the network.

Relay Selection Scheme for Cooperative Communication Systems in Fixed Decode-and-Forward Mode

2014 ◽  
Vol 6 (2) ◽  
pp. 68-77
Author(s):  
Jyh-Horng Wen ◽  
Jheng-Sian Li ◽  
Hsiang-Shan Hou ◽  
Cheng-Ying Yang
Keyword(s):  
Cooperative Communication ◽  
System Performance ◽  
Communication Systems ◽  
Relay Selection ◽  
Spatial Diversity ◽  
Search Method ◽  
Exhaustive Search ◽  
Decode And Forward ◽  
Selection Scheme ◽  
Relay Stations

Cooperative system is a tendency in the future communications because it provides a spatial diversity to improve the system performance. This work considers the cooperative communication systems in Fixed DF Mode. The scenario includes multiple source stations, multiple relay stations and multiple destination stations. For the whole system, the maximum throughput approaching is the major purpose. Hence, to select the relay stations for signal transmission could be the important scheme to achieve the optimal system performance. With the exhaustive search method, easily to realize, the optimal selection scheme could be found with a highly complicated calculation. In order to reduce the computational complexity, a relay selection scheme is proposed. With different situations of the communication systems, the performances evaluations obtained with both the proposed algorithm and the exhaustive search method are given for comparison. It shows the proposed algorithm could provide a solution approaches to the optimal one. It could apply the proposed scheme to the practical without a delay because of long-time calculation.

scholarly journals Narrowband Interference Suppression in Wireless OFDM Systems

2009 ◽  
Vol 5 (1) ◽  
Author(s):  
Zlatka Nikolova ◽  
Georgi Iliev ◽  
Miglen Ovtcharov ◽  
Vladimir Poulkov
Keyword(s):  
Communication Systems ◽  
Multiple Access ◽  
Communication Channel ◽  
Digital Data ◽  
Communication Link ◽  
Narrowband Interference ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Signal Distortions ◽  
Channel Distortion

Signal distortions in communication systems occur between the transmitter and the receiver; these distortions normally cause bit errors at the receiver. In addition interference by other signals may add to the deterioration in performance of the communication link. In order to achieve reliable communication, the effects of the communication channel distortion and interfering signals must be reduced using different techniques. The aim of this paper is to introduce the fundamentals of Orthogonal Frequency Division Multiplexing (OFDM) and Orthogonal Frequency Division Multiple Access (OFDMA), to review and examine the effects of interference in a digital data communication link and to explore methods for mitigating or compensating for these effects.

scholarly journals ИССЛЕДОВАНИЕ ЗАМИРАНИЙ В СИСТЕМЕ СВЯЗИ С ИСПОЛЬЗОВАНИЕМ ТЕХНОЛОГИИ OFDM

2018 ◽  
pp. 47-53
Author(s):  
Алексей Андреевич Бреславец ◽  
Александр Владимирович Тоцкий
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Communication System ◽  
System Performance ◽  
Rayleigh Fading ◽  
Communication Channel ◽  
Signal Propagation ◽  
Communication Link ◽  
Suggested Approach ◽  
Communication System Performance

A new technique exploited for estimating of fading influence in multipath signal propagation environment for communication system using OFDM (Orthogonal frequency-division multiplexing) technology is proposed. Rayleigh fading model is considered and studied in suggested approach. Wi-Fi network has been selected as a basis system for study performance of OFDM communication system operating in multipath and noisy communication channel. Preliminary experimental measurements and computations have been carried out in order to evaluate received signal parameters after test signal propagation through multipath communication link contaminating transmitted signal under influence of random Rayleigh fading. An algorithm has been developed that makes it possible to perform computations according considered model. Software corresponding to suggested algorithm has been developed. Proposed software contains user interface that is written in order to automate the process of computations. Developed software was examined experimentally for statistical study of interference behavior and its influence on the OFDM communication system performance. The following data were taking into account in investigations: Rayleigh fading; user's motion; number of operating OFDM subcarriers; number of receiving antennas; additive normal noise. The influence of these factors on the communication system performance was evaluated by computation the value of bit error rate (BER) values. Suggested software also gives an opportunity investigating the number of bit errors and appearance of the signal in the time and frequency domains at different stages of transmission. Computer simulations results were obtained for a sequence of test Monte Carlo runs depending on: the speed and angle of the user's traffic; the intensity of the additive Gaussian noise in communication channel; variations of the number of OFDM subcarriers; the number of antennas contained in the user equipment. Computer simulation results demonstrate the following: bit error rate values tend to increasing with increasing the user velocity as well with decreasing the number of antennas and subcarriers. It has been also shown decreasing the signal-to-noise ratio value under influence of additive noise with a Gaussian distribution according to decreasing the number of OFDM subcarriers and number of antennas in MIMO system.

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