1. Purpose and scope of the system
In the current wireless networking standards, omni-directional antennas are used to establish connection between the base station and the user. The radiation emitted from this antenna is spread uniformly in a horizontal manner. These antennas are employed because the base station is not aware of the location of the user. Hence most of the radiated beam is lost or dispersed. Furthermore radiation from neighboring base stations with the same frequency will cause interference. If it is possible to concentrate the beam/radiation only the user and introduce nulls in the area of the interference, most of the radiated power can be made useful and gives users with extended range.
Introducing SMART antennas will enable antennas to spatially divide their individual cells into quadrants and transmit specific to that quadrant. In this way, most of the transmitted power is utilized. It also reuses the channel within the cell, in that each beam transmitted within the cell can have the same frequencies without co-channel interference, while in the current system the same is avoided when different antennas transmit in the same frequencies in a non-neighboring cell. Therefore the number of channels used within a cell can be increased.
2. Problem statement
How to improve throughput in wireless networks using SMART Antennas
3. Current system
In the current system, omni-directional antennas are used. These antennas have their radiation pattern spread isotropically across a plane parallel to the earth surface. Not knowing the direction of the end-user is the greatest disadvantage of this system. The space in the cell not used by the users is unnecessarily covered by these antennas. Plus co-channel interference ...
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Wireless is a methodical account of the early development of wireless telegraphy and the inventors who made it possible. Sungook Hong examines several early significant inventions, including Hertzian waves and optics, the galvanometer, transatlantic signaling, Marconi's secret-box, Fleming's air-blast key and double transformation system, Lodge's syntonic transmitter and receiver, the Edison effect, the thermionic valve, and the audion and continuous wave. Wireless fills the gap created by Hugh Aitken, who described at length the early development of wireless communication, but who did not attempt "to probe the substance and context of scientific and engineering practice in the early years of wireless" (p. x). Sungook Hong seeks to fill this gap by offering an exhaustive analysis of the theoretical and experimental engineering and scientific practices of the early days of wireless; by examining the borderland between science and technology; depicting the transformation of scientific effects into technological artifacts; and showing how the race for scientific and engineering accomplishment fuels the politic of the corporate institution. While the author succeeds in fulfilling these goals, the thesis, it seems, is to affirm Guglielmo Marconi's place in history as the father of wireless telegraphy.
Radio systems must have transmitter to modulate some property of the energy produced to impress a signal on it. To using amplitude modulation or angle modulation ,which can be frequency modulation or phase modulation. Radio systems have antenna to convert
Frink, S. (2012, August). Space Communications Forge Ahead, Military & Aerospace Electronics, 23 (8), p1, 12
Johnson, D., Maltz, D. (1996). Dynamic Source Routing in Ad-hoc Wireless network. Print ISBN: 0 79239697 0
For physically small antennas, the Wheeler cap method is highly preferred for measuring the radiation efficiency. According to this method, if a radiation shield is placed around the antenna so as to enclose the near fields of the antenna, the radiation resistance of the antenna is reduced to zero while the loss resistance and the stored energy remain the same as for the unshielded antenna. When covering the antenna with a metal cap, the radiation is suppressed and the input power (proportional to the input resistance) is equal to the power loss (proportional to the loss resistance). Without the cap, the input power is equal to the radiated power plus the power loss (input resistance + loss resistance). The radiation efficiency of the antenna can be obtained from these two parameters.
Here we design single-antenna based system which checks the traffic probe regarding the communication between different users in a connected area under coverage. To increase the coverage area and traffic collection, we can increase the antenna gain and amplifiers with noise reduction techniques. There are some procedures, experiments and also theorems in implementing the right way of tracking the forensic devices. As in this experiment the limit of detection is around 1km of radius and the accuracy of forensic localization has a error limited to 10 meters which is a serious threat to location privacy.
Cell phones use radio frequencies to transmit signals. Radio Frequencies (RF) are a form of electrical waves similar to those used in radios, microwaves, radars or satellite stations. They are emitted from a transmitter, and received using an antenna. This telephony technology is restricted geographically to small zones called “Cells”. Every cell has a base station capable of sending and receiving radio waves. When a call is started a signal leaves the handheld unit headed to the closest base station. This station answers by allocating a specific channel to the unit. When this “channel” is established, modulated radio frequency signals are both received and transmitted. The head of the user is in the near field of use because the distance from the antenna to the head is a few centimeters. (Blettner & Berg 2000) If the antenna is inside the body of the phone, the exposure to Radio Frequencies is greater. The antenna might be requesting a stronger signal to contest with the interference of the battery or the actual shell of the phone’s body.
6) Michele Zorzi, “Wireless Sensor and networks: Recent trends and Research Issues’’, University of Padova, Italy, IEEE communication society, Poland, April 28-30, 2008.
There are 4 unknowns: the coordinate of receiver position X and clock bias b. The Iterative Least Square (ILS) can be used to calculate these unknowns. The following is a brief illustration of process of Iterative Least Square in flowchart as shown in Figure 11. In the appendix, the Iterative Least Square method on Matlab functions is presented.
There have been a lot of significant advances in modern technology. This in turn has allowed to communication to advance as well. The first wireless cell phone was created in 1973 and it weighed about two and one-fifth pounds. However, the f...
Wireless technology has come from the basics of cellular usage to sensors in the medical field. Wires are now a thing of the past in today’s world with technology forever revitalizing. Wi-Fi (Wireless Network) or 802.11 networking is a phenomenal way of providing wireless Internet at a low cost. Using radio waves, a wireless network connects a PC, mobile phone or just about anything that connects to the internet wirelessly via a router.
Barcodes are used everywhere around us. They are used to track products through shipment, track products at a store and speed up and enhance the checkout process, as well as allowing faster access to information. Barcodes began to be used heavily in the 1970’s. This began a great movement in the consumer industry, speeding up the checkout process and allowing easier inventory tracking. However, just like all technologies, barcodes have been enhanced many times over and are being replaced by better, more efficient systems (Bonsor).
The waves can be absorbed and reflected by surrounding objects before they reach the nearest cell tower. For example when you put your phone next to your head, during a...
3. Brain, Marshall, and Tom Harris. "How GPS Receivers Work." 25 September 2006. HowStuffWorks.com. 01 June 2010.