Category archives for: Mobile Communication

SDMA

SDMA: SDMA by means of physical separation methods which allow the sharing of wireless channels. For example, a single channel can be used simultaneously as users far enough apart from each other to avoid interference. Known as frequency re-use, the method is widely used in cellular radio systems. Cell-sites at a distance from each other […]

OFDMA

OFDMA: OFDMA is the access method that is used in the Long-Term Evolution (LTE) cellular system in order to accommodate multiple users in a given bandwidth. Orthogonal Frequency Division Multiplexing (OFDM) is a modulation method that divides a channel into multiple orthogonal narrow bands so that they do not interfere with each other differs. Each […]

CDMA

┬áCDMA: CDMA is a purely digital techniques. It is also known as spread spectrum because it is a digitized version of the analog signal and is distributed over a wider bandwidth on a lower power level. This method is called Direct Sequence Spread Spectrum (DSSS) and (fig. 4). The digitized and compressed voice signals in […]

TDMA

TDMA: TDMA is a digital technique that divides a channel or a band in the time slots . Each time slot is used to send a byte or other portion of the digital signal for each successive serial data format . This technique works well with slow speech data signal , but it is useful […]

FDMA

FDMA: FDMA is the process of dividing a channel bandwidth or more separate bands , each for use by a single user (Fig. 1). Each individual band or channel is wide enough to accommodate the spread spectra transmissions. The transmitted data is modulated on each sub- carrier, and all of them.   FDMA divides the […]

LTE

LTE: Long Term Evolution , the successor to UMTS and HSPA has been deployed and is the way forward for high – speed mobile services. In its first form it is a 3G or as some like to call a 3.99 g technology , but with further additions in the technology met the requirements for […]

GPRS

GPRS: GSM is the most successful second-generation mobile technology , but the need for higher data rates spawned new developments in the data can be transferred at higher rates. The first system to have an impact on the market is GPRS. The letters stand for GPRS General Packet Radio System GPRS technologies enable higher data […]

Cell Phone Chargers to go Green

Cell Phone Chargers to go Green: Today mobile phones have become an integral part of our lives and are the most common form of communication. Frequent use of the mobile phone, the more necessary is the need for eco – pollution posed by the huge number of still -in- use and out -or- curtail use […]

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