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Methini, M.
- Channel Estimation and Equalization of Fi-Wi Uplink for Multiuser Networks
Authors
1 Electronics and Communication Engineering Department, Sri Sairam Engineering College, IN
Source
Wireless Communication, Vol 4, No 9 (2012), Pagination: 518-523Abstract
Radio-over-fibre (ROF) has received increasing attention for its ability to enable broadband wireless access. This fibre-based wireless access scheme meets the demand for broadband service by integrating the high capacity of optical networks with the flexibility of radio networks (the optical and wireless channels are concatenated with one another).There is however, impairments that come with this appealing technology. The nonlinear distortion of the optical link and the multipath dispersion of the wireless channel are two of the major factors. In order to limit the effects of these distortions, estimation and subsequently equalization of the concatenated fibre-wireless (Fi-Wi) channel needs to be done. In the proposed technique, estimation of the fibre-wireless uplink in a multiuser CDMA environment is presented using pseudonoise (PN) training sequences. Estimation is done in a multiuser CDMA communication system where all users transmit their signal simultaneously. Correlation analysis is applied to identify the channel impulse response (CIR). The estimation and equalization are performed in the presence of wireless and optical channel noise. Estimation of both the linear and nonlinear systems in the presence of ten independent users is simulated. Then the fiber-wireless uplink is equalized in a single user environment using Hammerstein type decision feedback equalizer.
Keywords
Code Division Multiple Access, Channel Estimation and Equalization, Fiber-Wireless Systems, Hammerstein Decision Feedback Equalizer, Parameter Estimation & Identification, Radio over Fiber.
- Portable Navigation Aid for Marine Monitoring and Rescue
Authors
1 Department of Electronics and Communication Engineering, Sri Sai Ram Engineering College, Chennai-44, IN
Source
Automation and Autonomous Systems, Vol 4, No 6 (2012), Pagination: 232-236Abstract
Large ships or vessels with a more powerful engine are often well-equipped with advanced communication devices such as satellite communications or high power two-way radio with central base stations located along the coastal line but small fishing boats are either ill-equipped or not equipped at all of any type of radio communication equipment. This paper addresses these problems by using a portable device which will give an audio visual indication to fishermen if they approach or cross international borders. An visual alert will be provided to fishermen if they about to cross international boundaries by using LCD display. Also an authority at coastal unit gives voice indication to fishermen in case of emergence purposes. Using GPS receiver, exact position can be located. The information is send to the microcontroller, which compares the current coordinates with preprogrammed boundary coordinates. If the fishermen is about to cross the border, an alarm will alert them.
Hence all these features make a complete portable device for fishermen that can help not only to move in sea but also to gain access for information even in the middle of the vast waters.