IT Infrastructure
Abstract
Since the internet invention, modem as evolved tremendously and impacted lives globally. Modems transmit digital information over a telephone line by converting it into electrical signals and demodulate it at the receiver via another modem. Based on the amount of data a modem can transmit per unit of time, typically bits per seconds, they are classified. In next section of this paper, it will examine namely 3G and 4G LTE modem technology compare the latter in light to multiplexing and error correction when transmitting and exchanging data via the internet. Further ahead, and the paper will compare encoding of MP3, FLAC, and WAV file sound to CD sound over headphone, followed by an examination why noise is a bigger problem on analog transmission. Finally, by explaining under what circumstance will forward error correction work.
Introduction
The advent of 4G internet service changed the game of internet since its introduction attracting numerous parties to it. It is an improvement of the 3G internet with increased bandwidth able to video conference on a mobile technology, downloads, and uploads files at a tremendous speed. It took over 4 years to finish developing 4G network. 3G, as the name suggest, is the third generation of internet. The third generation of standards of communication hardware is where it 3G internet was first founded and released in the market. 3G internet replaced 2.5G internet technology not so long ago. International Telecommunication Union Radio-communication (ITU-R) Sector of standard owned by the International Mobile Telecommunication IMT-2000 is enabled 3G internet became a reality. On the hand, 4G refers to the fourth generation of internet and mobile communication standards. Similarly, 4G internet substituted 3G with an added feature that enables mobile phone ultra-broadband internet access (Jin et al., 2013).
Multiplexing is a technique used in the transmission of data, which combines the different bandwidth of signals and then transmits them in one single channel. Multiplexing can allow a different online user to access a common channel to exchange data and in the process communicate a process known as multiple accesses typically (Jin et al., 2013). This method works by dividing frequency blocks in which different users can communicate and exchange data for example in WI-FI. 3G Code Division Multiple Access (CDMA) cellular is designed based on a code division multiplexing method that data are modulated in bits using higher frequency known as orthogonal sequence either by a pseudo-random or Walsh code known as Gold code to distribute them through a large frequency band. It then combines similar signals from different users through an identical frequency band (Jin et al., 2013).
In 3G CDMA cellular network to recover the signals, the receiver should have a similar distribution sequence that is copied in this combined signal a process called expanding. This technique of data transfer makes the CDMA more safe and strong. The bandwidth in 3G CDMA can reach up to 5MHz on a cellular.
Over the last few decades, there has been a tremendous explosion of internet users, which forced radio waves expansion from GSM to HSPA +, a 4G network. Unlike 3G, 4G cellular uses a higher modulation spectrum such 8-PS, 64QAM, 16QAM among others. It was also observed that 3G CMDA had a considerable low data rate compared to 4G OFMDA cellular since its bandwidth is 25 KHz per user. Secondly, during peak hours data became congested. Lastly, guard periods caused poor spectral ratio hence the development of 4G LTE that came with a scalable bandwidth, Low Intersymbol Interference (ISI), and can allow different users to access different bandwidth depending on the available resource. 4G LTE, unlike 3G, lack guard band hence no wastage and congestion of data on cellular technologies (Jin et al., 2013).
Comparison between MP3, FLAC, WAV and CD
The encoding used to compress files in MP3, FLAC, WAV uses small space than encoding used CD while the time for encoding in an MP3 is much longer than that on a CD due to its uncompressed files. Secondly, CD has a better sound quality compared to MP3, FLAC and wave files which sound better in a headphone. This is because during compression of files in an MP3, the integrity of the file is compromised thus its sound which makes it sound a bit low compared to files on CDs. MP3 files can be supported with a specific audio instrument but CD is a player in all audio instrument Ruzanski (2006).
Analog and digital signal
Both analog and digital signal convey information using electrical signals. Analog uses electrical impulses to transmit information while digital signal depends on binary, which are ones, and zeros. Since analog signals are electrical impulses, they are easily affected by noise, which disrupts sounds wave in the air. Digital signal cannot be easily be affected by noise because of the binary in nature because noise itself is analog in nature (Broesch, 2009).
Forward error correction occurs when a transmission error occurs frequently and their retransmission is expensive which is more effective. It normally occurs when Wireless transmission or satellite is used. It involves the transmission of data in impulse so that certain errors are corrected instead of retransmission of data (Broesch, 2009).
REFERENCE
Broesch, J. D. (2009). The Analog-Digital Interface. Digital Signal Processing, 7-25. doi:10.1016/b978-0-7506-8976-2.00002-x
Jin, Y., Wu, L., Feng, M., & Deng, L. (2013). An MCP-EBPSK Modem with Random-polar. Journal of Electronics & Information Technology,34(7), 1647-1652. doi:10.3724/sp.j.1146.2011.01359
Ruzanski, E. (2006). Effects of MP3 encoding on the sounds of music. IEEE Potentials,25(2), 43-45. doi:10.1109/mp.2006.1649011
