discussed. With features such as closed subscriber group, self-organising networks, location services, enhancement cell ID and Multimedia Broadcast services this is a standard which pretty much became the norm. Technologies such as Orthogonal Frequency Division Multiplexing (OFDM) and Multiple-Input Multiple-Output(MIMO) which were instrumental in the evolution to the LTE-Advanced are also discussed. scalable multiple transmission bandwidths are supported by LTE including one for the packet-switching
A single frequency radio wave does not transmit any information. In order for information to be transferred, the frequency needs to vary in time. The range of frequencies that a single channel can occupy is what is known as its bandwidth. In order to allow for multiple calls to be handled by a single base station, multiplexing techniques are used which are ways of combining multiple signals. The four main techniques include: frequency division multiple access (FDMA), time division multiple access
can cope up with their competitors. 802.11a and 802.11g were the most popular protocols prior to the revision of 802.11n standard. 802.11a is a wireless protocol introduced in 1999. This protocol works in a 5GHz band and uses basic orthogonal frequency-division multiplexing(OFDM) waveform and attains a maximum data rate of around 54 Mbps. It was one of the most widely used protocols for wireless systems. However, 802.11g operated at 2.4 GHz band and used the same OFDM waveform as that of 802.11a. It
transmissions are. Analog transmissions are a continuous variable in amplitude and frequency. The frequency band that they operate over defines analog circuits. People generally produce a bandwidth of 9,900Hz with frequencies in the range of 100Hz to 10,000Hz. Speech that falls between 250Hz and 3,400Hz is considered intelligible speech and therefore the network circuits use bandwidth-limiting filters designed to filter out all frequencies above 4,000Hz. For these reasons, analog circuits are low-speed data communications
Wireless Application Protocol (WAP) that is being proposed by several vendors to standards bodies. The Wireless Application Protocol works on top of standard data link protocols, such as Global System for Mobile communication, code-division multiple access, and Time Division Multiple Access, and provides a complete set of network communication programs comparable to and supportive of the Internet set of
describes how to quickly determine if a MIMO channel is capable of supporting spatial multiplexing when given a particular signal-to-noise ratio (SNR). The term “condition number” will also be introduced when dealing with recovery of MIMO transmission. Many wireless systems used today have improved data capacity using the multi-antenna system. However, not all MIMO wireless systems are suitable for spatial multiplexing. In order to accommodate this benefit, the wireless channel must have the appropriate
wireless devices and applications Cognitive radio technology proposed tempting solution for spectral crowding problem by introducing the opportunistic usage of frequency bands. Which are not heavily occupied by licensed users since they cannot be utilizing by the users other than the licensed owner at moment. Orthogonal Frequency Division Multiplexing (OFDM) is one of the widely used technologies in wireless communication systems which have the potential of fulfilling the requirements of cognitive radios
Data Center: Data center, in the context of big data, is not only for data storage but it plays significant role to acquire, manage and organize the big data. Big data has uncompromising requirement for storage and processing capacity. Hence the data center development should be the focus for effective and rapid processing capacity. With the increasing scale of data centers, the operational cost should be reduced for the development of data centers. Today’s data centers are application-centric, powering
1. Introduction • Wi-Fi also common spell with Wifi or interCap word WiFi, is one of the most popular wireless communication standards on the market that exchange data or internet by wirelessly using radio waves. Wi-Fi is technically a trademarked brand name for the wireless standard owned by the Wi-Fi Alliance, much like Bluetooth® is trademarked by the Bluetooth Special Interest Group. The Wi-Fi Alliance also defines Wi-Fi as any WLAN product that based on the IEEE 802.11 standard. However, only
The Emergence of Satellite Radio While the transition of television to a digital technology with its improved picture and sound quality has been a much publicized and controversial process, television's venerable ancestor, radio, has stayed in the background. But this year, in the United States, radio broadcasting is making its own digital leap. Two start-ups are introducing a new type of radio broadcast--subscription-based digital audio sent from satellites. With satellite digital audio radio