scholarly journals Improving BER and data throughput using adaptive modulation level MC-CDMA technique in underwater wireless communication

2018 ◽  
Vol 7 (3.3) ◽  
pp. 299
Author(s):  
Jaya. T ◽  
P Vijayalakshmi ◽  
V Rajendran
Keyword(s):  
Adaptive Modulation ◽  
Modulation Scheme ◽  
Underwater Communication ◽  
Vehicle Noise ◽  
Data Throughput ◽  
Wide Range ◽  
Code Division Multiple ◽  
Channel Environment ◽  
Underwater Wireless Communication ◽  
Modulation Level

Underwater communication has a wide range of applications like environmental monitoring to predict the natural disasters, underwater ex-ploration and military applications. The need for effective underwater communication is the high demand in the present scenario. The im-plementation of precise modulation technique is also important because the underwater channel environment is time variant due to various noises present in the underwater like natural and vehicle noise (mechanical noises). The bandwidth is also highly limited in underwater communication. The existing method is adaptive modulation based OFDM system. This method has low spectral efficiency, however, each symbol is modulated with different carriers. The proposed method is Adaptive Modulation Level MC-CDMA (Multi carrier Code Division Multiple Access). The CDMA techniques share the same carrier frequency to multiple number of users. It adapts the modulation scheme according to the present channel conditions in the underwater. The performance of the proposed system improves the Data Throughput and Bit Error Rate. 

scholarly journals Comparison Simulator Data Rate Modulation QPSK and 16 QAM System WCDMA (Wide Code Division Multiple Access) and HSDPA (High Speed Downlink Packet Access)

2015 ◽  
Vol 1 (1) ◽  
pp. 34-42
Author(s):  
Herdianna Kusuma W
Keyword(s):  
High Speed ◽  
Adaptive Modulation ◽  
Data Rate ◽  
User Equipment ◽  
Expected Improvement ◽  
Modulation Scheme ◽  
Bit Rate ◽  
Symbol Rate ◽  
Packet Access ◽  
Code Division Multiple

HSDPA (High Speed Downlink Packet Access) is the upgrade performance data packets extraordinary against WCDMA thus producing top speed 14,4 Mbps. One of the goals the creation of HSDPA is as an improvement over previous technologies. The expected improvement of HSDPA technology increasing the data rate is capable of exceeding data rate in order to WCDMA customer satisfaction in accessing multimedia content such as streaming video and data at high speed. Data Rate is the maximum data rate that can be accepted by the UE (User Equipment) in ideal conditions. One of the factors that affect the data rate is modulation scheme used by each of the technologies. QPSK modulation is used in WCDMA system and adaptive modulation (QPSK and 16QAM) is used in HSDPA system.In the research the results obtained by selection of symbol rate of 480 kbps bit rate will yield 960 kbps while the selection symbol rate is 960 kbps will produce 1920 kbps bit rate using modulation QPSK modulation. As for 16QAM modulation, symbol rate of 480 kbps produces 1920 kbps and symbol rate is 960 kbps bit rate produces 3840 kbps. Of the trial results, the more number of bits sent then the higher data rate that can be accepted by the UE (user equipment).

Performance of LED for line-of-sight (LoS) underwater wireless optical communication system

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Alaa G. Nasser ◽  
Mazin Ali A. Ali
Keyword(s):  
Optical Communication ◽  
Link Quality ◽  
Line Of Sight ◽  
Modulation Scheme ◽  
Underwater Communication ◽  
Optical Communication System ◽  
High Data ◽  
Wireless Optical Communication ◽  
Noise Rate ◽  
Wireless Optical Communications

AbstractUnderwater wireless optical communications (UWOC) recently emerge as a solution to the problem of underwater communication for link with a high data rate, low delay, safety, and high immunity. In this study, the line of sight (LoS) method based on LED used for UWOC with different modulation schemes. The bit error rate (BER), signal-to-noise rate, and quality factor are used for assessing system performance and link quality. Besides the effect of transmitting angle, distance link (d), and transmitting power (PT) are analysed. Results show that 8-pulse position modulation (PPM) is the best modulation scheme for achieving a good link in the LoS method.

The Influence of In-Vehicle Noise on Speech Recognition for Automotive Voice-Activated Control Systems

2002 ◽  
Vol 33 (9) ◽  
pp. 19-23
Author(s):  
By Dave G. Fish
Keyword(s):  
Speech Recognition ◽  
Control Systems ◽  
Convenient Method ◽  
Vehicle Control ◽  
Climate Control ◽  
High Demand ◽  
Vehicle Noise ◽  
Control Functions ◽  
Wide Range ◽  
Vehicle Systems

Voice activation provides a safe and convenient method of controlling vehicle systems such as in-car entertainment, telecommunications and climate control. In the fullness of time it is likely that there will be a high demand across all vehicle classes for such systems for a wide range of vehicle control functions. One of the challenges facing their development and introduction into vehicles is that of the in-vehicle noise environment.

scholarly journals Establishment Network by Using FSO Link Based on MD Code for Hybrid SCM-SAC-OCDMA Wireless System

2018 ◽  
Vol 8 (6) ◽  
pp. 5107
Author(s):  
Rashid Ali Fayadh ◽  
Mousa K. Wali ◽  
Mehdi F. Bonneya
Keyword(s):  
Mesh Networks ◽  
Wireless Systems ◽  
Wireless Channel ◽  
Mesh Network ◽  
Spectral Amplitude ◽  
Modulation Scheme ◽  
Atmospheric Effects ◽  
Free Space Optic ◽  
Spectral Amplitude Coding ◽  
Code Division Multiple

<p>Since the wireless systems are working under nature environments and influenced by turbulence, weather in Iraq that leads to extended amount of fading signal, dissipation or attenuation. Basic “hybrid Subcarrier Multiplying Spectral Amplitude Coding (SCM-SAC) of Optical Code Division Multiple Access (OCDMA)" indoor or outdoor optical system depends on generally “Multi-Diagonal (MD)" security code by using optical space known as “Free Space Optic (FSO)" that was proposed in this work. It is found that the mention hybrid wireless systems can be used in operating mesh networks. The main proposed idea of hybrid optical technique was analyzed and simulated by normally taking into simulation account that the directly effecting by rain and haze attenuations. In addition, there are mention and description for atmospheric effects, FSO mesh network, modulation scheme, simulation, and the data security. From simulation results, the hybrid system using MD code produces reduced “bit-error rate (BER)" at heavy storm rain to distance or range of 500 m and at drizzle rain up to 2500 m range. And also investigates the performance of using the proposed system with radio over fiber (RoF) for UWB signals through indoor propagation in building applications of wireless channel.</p>

WiMAX and Wi-Fi Services through Mobile Networks

2016 ◽  
pp. 160-189
Author(s):  
Sajal Saha ◽  
Angana Chakraborty ◽  
Asish K. Mukhopadhyay ◽  
Anup Kumar Bhattacharjee
Keyword(s):  
Mobile Networks ◽  
Antenna Selection ◽  
Adaptive Modulation ◽  
Path Loss ◽  
Mobile Wimax ◽  
Modulation Scheme ◽  
Coding Schemes ◽  
Radio Resources ◽  
Integrated Architecture ◽  
Restricted Mobility

WIFI and WiMAX became popular worldwide due to simplicity of installation and cost reduction compared with traditional DSL cable. The key challenge of WiFi is the restricted mobility of the user whereas mobile WiMAX (IEEE 802.16m) provides ubiquitous environment to the user. The recent challenges of WiMAX is managing radio resources (both licensed and unlicensed) efficiently through different QoS service classes, implementing proper modulation and coding schemes at PHY, proper antenna selection in MIMO to achieve better QOS. User can avail the benefits of speed and mobility through an integrated architecture comprising WiFi and WiMAX. This chapter provides an in depth performance evaluation of Mobile WiMAX and WiFi under various Modulation and Coding Schemes (MCS), cyclic prefixes and different path-loss models under integrated environment. Moreover, we present an optimized adaptive modulation scheme that senses the SNR and adaptively switches to required MCS to achieve desired level of QoS and link stability.

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