Design and recording of holographic diffuser for controlled angular distribution of light
Now-a-days diffusers play a pivotal role in many applications. It is desirable in many applicatio... more Now-a-days diffusers play a pivotal role in many applications. It is desirable in many applications that angular distribution of scattered light must be controlled in a particular manner. Present paper reports on design and recording of holographic diffusers for controlling the angular distribution of the scattered beam. Experimental results from recorded holographic diffuser have been compared with the conventional diffuser.
The exponentially growing need for higher data rates and the ubiquitous usage of smartphones has ... more The exponentially growing need for higher data rates and the ubiquitous usage of smartphones has led to unprecedented issues in providing seamless communication while satisfying bandwidth constraints. Enabling Device-to-Device (D2D) communication in the millimeter-wave (mm-Wave) network enhances throughput and bandwidth but at the cost of higher pathloss attenuation. Also, D2D communication introduces interference in the traditional cellular network (CN), leading to degradation in the system performance. Thus, the proposed scheme applies dynamic mode selection criteria for efficient D2D communication in a 5G mm-Wave CN. The radius of coverage of D2D users (D2Ds) is derived for switching of the modes, i.e. from inner to outer. The outer mode switching occurs when the D2Ds suffer from extensive pathloss attenuation or with increase in coverage radius. Furthermore, power optimization is done to obtain optimal D2D transmit power thereby, enhancing the data rate, which is solved using th...
Relay aided device-to-device (D2D) communication has the potential to increase the capacity and c... more Relay aided device-to-device (D2D) communication has the potential to increase the capacity and coverage of the network and enhance the quality of service (QoS). Here, in this paper we propose a single cell where D2D and cellular users co-exist in an underlaying 5G mm-Wave cellular network. Two modes are proposed for D2D communication which minimizes the interference namely, direct and relay mode. Direct mode operates at 2 GHz carrier frequency while relay mode implements full duplex amplify and forward (FDAF) relay strategy at 28 GHz frequency. Conditions are applied on the derived expression for radius of coverage, R t for switching of modes. The closed form expressions of performance metrices namely, spectral efficiency (SE) and energy efficiency (EE) are derived using stochastic geometry as a tool for both the modes to evaluate the system performance. Expressions for probability distribution function (PDF) and cumulative distribution function (CDF) are also derived and verified ...
Pathloss attenuation analysis for D2D communication in 5G mmWave networks
2020 Advanced Communication Technologies and Signal Processing (ACTS), 2020
The effect of pathloss attenuation on D2D communication in mmWave underlaying 5G networks is unpr... more The effect of pathloss attenuation on D2D communication in mmWave underlaying 5G networks is unprecedented. Pathloss attenuation is catered through a variety of sources into the wireless communication system. It is imperative to model a scheme through which the attenuation can be minimized. This paper focuses on a scheme based on the trade-off between pathloss attenuation and distance between the D2D users for enhancing QoS of the cellular as well as D2D users. This is achieved by mode assignment through reuse and dedicated or cellular mode. The decision is made based on the distance between the D2D users and also the pathloss attenuation attached to it as pathloss plays an equally pivotal role for a mmWave network. Finally, a comparison is also made with other existing schemes to prove its efficacy.
Enabling D2D communication in the mm-Wave band has many obstacles which must be mitigated. The pr... more Enabling D2D communication in the mm-Wave band has many obstacles which must be mitigated. The primary concern is the introduction of interference from various sources. Thus, we focused our work on the performance of decode and forward (DF) relay assisted D2D communication in the mm-Wave band for increasing the coverage probability and energy efficiency (EE). Three modes are proposed for D2D communication to prevail. Bit-wise binary XOR operation is executed at the relay node which increases the security feature. Radius of coverage expression is derived which indicates the switching of the modes. The diffused incoherent scattering power is also considered as a part of power consumption. Furthermore, a unique relay selection scheme, Dynamic relay selection (DRS) method is proposed to select the optimal relay for information exchange. Comparison of the proposed DF relay scheme with amplify and forward (DF) scheme is also shown. Finally, simulation results prove the efficacy of the pro...
Power control scheme for device‐to‐device communication using uplink channel in 5G mm‐Wave network
Transactions on Emerging Telecommunications Technologies, 2021
Mm‐Wave communication ushers next‐gen communication to new heights guaranteeing higher speed and ... more Mm‐Wave communication ushers next‐gen communication to new heights guaranteeing higher speed and throughput. Enabling device‐to‐device (D2D) communication in next‐gen wireless communication is a Herculean task. This is due to introduction of pathloss attenuation by various environmental factors which deteriorates the signal. This article aims to minimize the effect of interference for quality reception of signals for D2D communication and increase system throughput. Thus, a power control scheme is proposed in underlay mode for uplink channel in mm‐Wave band. Here, D2D communication takes place through two modes namely, general mode and mm‐Wave mode. In presence of large number of proximity D2D users and increasing pathloss attenuation, it switches to mm‐Wave mode for communication. The formulated problem is converted to semiconvex form by expressing it into exponential form in Laplace domain. Our final objective is to maximize the energy efficiency (EE) of the proposed system under ...
Interference Mitigation Methods for D2D Communication in 5G Network
Cognitive Informatics and Soft Computing, 2020
Interference poses to be a grave threat to wireless communication systems. Quest for higher data ... more Interference poses to be a grave threat to wireless communication systems. Quest for higher data rate and higher energy efficiency has led to a paradigm shift. Since the inception of cellular technology in 1980, researchers are in search of a communication system which can exhibit high data rate, low latency, higher capacity, energy efficiency and spectrum efficiency. This led the researchers to explore 5G, operating in mmWave band (30–300 GHz) which is expected to support uncompressed video streaming, 3D telepresence, holographic communication and other multimedia applications. But all these technological advances suffer from a foe, i.e., cross-channel interference and co-channel interference. Thus, this paper chronologically discusses the various models applied to minimize or eradicate the problem of interference in 5G communication systems. Future research directions have also been discussed.
Here we report a system which can be operated using electroencephalography (EEG) signals generate... more Here we report a system which can be operated using electroencephalography (EEG) signals generated during eye blink and thus may be useful for persons with locomotive and other disabilities for performing their day-today activities. EEG signals are processed by a microcontroller and based on programming, the microcontroller takes a decision to perform the desired task by actuating a corresponding device from several devices connected to the system. An important feature of the system is that it can be adapted to particular needs of the user and can be attached/detached for actuation of different appliances according to the user's condition and requirements.
Diffusers play an important role in modern days display technology. Holographic diffusers offer e... more Diffusers play an important role in modern days display technology. Holographic diffusers offer effective control on various parameters of the diffused light like diffusion angle, uniformity of light etc. Present work reports a procedure for realization of a holographic diffuser through which multichannel restricted view display is achieved such that information can be conveyed to and viewed from multiple selective viewpoints only. Such type of diffusers will be helpful in enhancing security feature of the displayed information by enabling only authenticated persons to have access to the information. Fabrication process of the holographic diffuser is described and experimental results are discussed.
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Papers by Subhra Sarma