1.1 INTRODUCTION
The aim of third and fourth generation (3G/4G) mobile networks is to provide users with high data rates, and to provide a wider range of services, such as voice communications, videophones, and high speed Internet access. A common challenge in a wireless system design is to overcome the eects of the wireless channel, which have multiple transmission paths and dierent delays. OFDM has a promising future as a new technology in several next generation wireless communication systems. The OFDM systems ability to combat the eects of multipath propagation with a relatively simple receiver structure made it the modulation of choice for some of the most prominent wireless technologies such as the IEEE 802.11 wireless local area
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These systems require analog oscillator and lter of much wider bandwidth and sharp cut-o. Therefore, the concept of OFDM was not gained so much attention or popularity because of the diculty in sub-carrier recovery without inter-sub-carrier interference by means of analog lters. Due to this reason only, a number of studies in the
1960s were dedicated for MCM employing overlapped band-limited orthogonal signals [12] [10] [13]. In the year 1967, B. R. Saltzberg suggested a MCM system employing Orthogonal time-staggered Quadrature Amplitude Modulation
(O-QAM) on the carriers [12]. The concept of MCM scheme employing timelimited orthogonal signals, which is similar to OFDM, was rst given by H. F.
Marmuth [14] in 1960.
A major breakthrough in the history of OFDM came in 1971 when Weinstein and Ebert used Discrete Fourier Transform (DFT) to perform baseband modulation and demodulation which eliminated the need of bank of subcarrier oscillators thus making the operation ecient and simpler [15] [16]. In
1979, after evolutionary growth and development in signal processing and VLSI technologies, high speed chips can be built around special-purpose hardware performing the large size Fast Fourier Transform (FFT) (ecient algorithm for
DFT) at aordable price [17] [18].
All the proposals of OFDM systems used guard spaces in frequency domain and a raised cosine windowing in time domain to combat
In the pursuit of opening a great venture with my business partner we are hoping to
To solve these problems a company can implement Wi-Fi on their network. This can reduce the price of implementing additional cable in the network.
Figure.10 (a) Hardware test bench set up (b) Gating pulses for 70 KHz from DSP processor (c) Input voltage and input current waveforms for 230Vrms (d) Input voltage and input current waveforms for 110 Vrms
In the recent years, wireless technologies have taken a new dimension in the ways society lives. Wireless broadband is available to everyone. Whether the users are at home, driving the car, sitting in the park, and it would even work while people are a pleasure boat ride in the middle of a lake. And because of this, the need to have information at any time and be connected in all places, all the time has been satisfied.
* Answer each of the following questions using the sequence and data from the iLab instructions. Answer all questions in full college-level sentences.
While Internet Service Providers (ISPs) want to create a tiered approach, saving the faster speeds for their premium customers while charging “heavy band-with users” in order to generate revenue, enhance their systems and build more robust, more advanced networks,
Data/Broadband Offerings. As the communications industry continues to move toward Internet-based technologies that are capable of blending traditional wireline and wireless services, AT&T plans to offer services that take advantage of these new and more sophisticated technologies. In particular, the company intends to continue to focus on expanding its AT&T U-verse high-speed broadband and video offerings, while developing IP-based services that allow customers to unite their home or business wireline services with their wireless service. In addition, this company’s size and leverage ought to allow it to take advantage of a maturing telecommunications space via increased spectrum, capacity, and data services.
The market for wireless communications has experienced incredible growth over recent years and wireless LANs have rapidly become a very
Also charging all the users the same price should be regulated essentially if the person uses more data they should pay for more data, and the people who doesn’t should pay less.
The Internet backbone is made of networks managed by a host of companies including Level3, MCI, and Qwest. The broadband service provides are Verizon, AT&T, and Comcast.(Robert Hahn and Scott Wallsten) Providers that carry approximately equal traffic.(Robert Hahn and Scott Wallsten) To conclude, broadband service pricing also is currently unregulated. Broadband providers must charge consumers a specific a price of zero and charge users only in certain ways.(Robert Hahn and Scott Wallsten) Knowing this, companies like Verizon, AT&T, and Comcast are wanting to charge extra just for using their
Directions: Select a topic from the case studies in the text. You may choose any of the topics, except those covered in previous assignments. Examples of topics you might investigate include: using telecommunications to keep in touch with co-workers; telecommunications innovation; managing telecommunications; emerging telecommunications technologies; and so on.
2. Strong Customer Base with more than 6 million versatile clients and around 1.7 million broadband associations
with a reduced cost based upon higher usage patterns which further leads to extended usage.
OFDM is a multicarrier transmission technique that splits the total available bandwidth into many narrowband sub-channels at equidistant frequencies. The sub-channel spectra overlap each other but the subcarrier signals are still orthogonal. The single high-rate data stream is subdivided into many low-rate data streams for the sub-channels. Each sub-channel is modulated individually and all the sub-channels are transmitted simultaneously in a superimposed and parallel form.