Wireless technology utilizes radio waves and/or microwaves to maintain communication channels between computers. Wireless technology is a more modern alternative to wired that relies on copper and/or fiber optic cabling between network devices.
Vikrant Ganpat Deshmukh
Kiran Sunildatt Trimbake
Vamanrao Ithape Polytechnic,
Need of wireless technology:-
We are know that wire technology is good
for high data transfer in networking. But its has some disadvantage like its use for short range communication and also we can not use for world wide communication .
Thatâ„¢s why need arise for is wireless technology
Wireless technology which is use for mobile communication, Bluetooth technology
& Wireless LAN.
We will be focusing on mobile communication which widely use for wireless technology
First in wireless mobile communication first generation is start with FDMA,TDMA,CDMA,ODMA.
FDMA (frequency division multiple access) is the division of the frequency band allocated for wireless cellular telephone communication into 30 channels, each of which can carry a voice conversation or, with digital service, carry digital data.
Â¢ FDMA requires high-performing filters in the radio hardware, in contrast to TDMA and CDMA.
Â¢ FDMA is not vulnerable to the timing problems that TDMA has. Since a predetermined frequency band is available for the entire period of communication, stream data (a continuous flow of data that may not be packetized) can easily be used with FDMA.
Â¢ Due to the frequency filtering, FDMA is not sensitive to near-far problem which is pronounced for CDMA.
Â¢ Each user transmits and receives at different frequencies as each user gets a unique frequency slot
But there is some disadvantage .the big problem is Crosstalk which causes interference on the other frequency and may disrupt the transmission.
TDMA (time division multiple access) is a technology used in digital cellular telephone communication that divides each cellular channel into three time slots in order to increase the amount of data that can be carried. Most 2G cellular systems, with the notable exception of IS-95, are based around TDMA, GSM.
Disadvantage of TDMA systems is that they create interference at a frequency which is directly connected to the time slot length.
TDMA also provides the user with extended battery life and talk time since the mobile is only transmitting a portion of the time (from 1/3 to 1/10) of the time during conversations. TDMA installations offer substantial savings in base-station equipment, space, and maintenance, an important factor as cell sizes grow ever smaller.
CDMA is a form of multiplexing, which allows numerous signals to occupy a single transmission channel, optimizing the use of available bandwidth.
The frequency of the transmitted signal is then made to vary according to a defined pattern (code), so it can be intercepted only by a receiver whose frequency response is programmed with the same code, so it follows exactly along with the transmitter frequency.
One major problem in CDMA technology is channel pollution, where signals
from too many cell sites are present in the subscriberâ„¢s phone but none of them is
dominant. When this situation arises the quality of the audio degrades.
One of the main advantages of CDMA is that dropouts occur only when the phone
is at least twice as far from the base station. it has a very high spectral capacity that it can accommodate more users per MHz of bandwidth. It uses a vocoder EVRC for noise reduction where the background noise is reduced.
GSM technology -
GSM (Global System for Mobile communication) is a digital mobile telephony system. GSM uses a variation of time division multiple access (TDMA) and is the most widely used of the three digital wireless telephony technologies (TDMA, GSM, and CDMA). GSM digitizes and compresses data, then sends it down a channel with two other streams of user data, each in its own time slot. It operates at either the 900 MHz or 1800 MHz frequency band on cell phone ,pocket pc ect.
1 Generation technology â€œ
In 1 Generation is use to mobile radio telephones and such technologies as Mobile Telephone System (MTS), Advanced Mobile Telephone System (AMTS), Improved Mobile Telephone Service (IMTS), and Push to Talk (PTT).
2 Generation technology -
Three primary benefits of 2G networks over their predecessors were that phone conversations were digitally encrypted, 2G systems were significantly more efficient on the spectrum allowing for far greater mobile phone penetration levels; and 2G introduced data services for mobile, starting with SMS text messages.
Â¢ The digital voice encoding allows digital error checking.
Â¢ Increase sound quality.
Â¢ Lowers the noise level â€œGoing all-digital allowed for the introduction of digital data transfer.
Â¢ SMS â€œshort message service.
Â¢ E-mail .
Edge technology â€œ
Enhanced Data rates for GSM Evolution (EDGE) (also known as Enhanced GPRS (EGPRS), The first major step in the evolution to 3G occurred with the introduction of General Packet Radio Service (GPRS). So the cellular services combined with GPRS became '2.5G.' EDGE is standardized by 3GPP as part of the GSM family, and it is an upgrade that provides more than three-fold increase in both the capacity and performance of GSM/GPRS networks. It does this by introducing sophisticated methods of coding and transmitting data, delivering higher bit-rates per radio channel.
EDGE can be used for any packet switched application, such as an Internet connection. EDGE-delivered data services create a broadband internet-like experience for the mobile phone user. High bandwidth data applications such as video services and other multimedia benefit from EGPRS' increased data capacity.
3 Generation technology-
3G wireless technology represents the convergence of various 2G wireless telecommunications systems into a single uniform global system which includes terrestrial and satellite components in its functioning.
3G or the third-generation wireless refers to near future developments in personal & business wireless technology, especially relating to mobile communications.
roaming capability, broad bandwidth and high speed communication (upwards of 2Mbps).
4 Generation technology â€œ
A 4G cellular system must have target peak data rates of up to approximately 100 Mbit/s for high mobility such as mobile access and up to approximately 1 Gbit/s for low mobility such as nomadic/local wireless access, according to the requirements. Scalable bandwidths up to at least 40 MHz should be provided.  A 4G system is expected to provide a comprehensive and secure all-IP based solution where facilities such as IP telephony, ultra-broadband Internet access, gaming services and HDTV streamed multimedia may be provided to users.
Fourth Generation Technology
Â¢ Faster and more reliable
â€œ100 Mb/s (802.11g wireless = 54Mb/s, 3G = 2Mb/s)
Â¢ Lower cost than previous generations Multi-standard wireless system
â€œBluetooth, Wired, Wireless (802.11x)