RECENT TRENDS IN WIRELESS, RADIO AND SATELLITE COMMUNICATION: A SURVEY ON WIRELESS FIDELITY :TECHNOLOGY AND STANDARDS

Authors :  Deepak Mathur¹,Shishir Jain²

¹[Asst. Professor (Comp. Sc.), Lachoo Memorial College of Science and Technology Jodhpur 342003, ]

2[Student (MCA IV), Lachoo Memorial College of Science and Technology, Jodhpur 342003]

Abstract

Wi-Fi stands for Wireless Fidelity. Wi-Fi is based on the IEEE 802.11 family of standards and is primarily a local area networking (LAN) Technology. The number of computing and telecommunications devices are  increasing and consequently the focus on how to connect them to each other. The Solution is to connect them by the cable or by the Wireless technology Wi-Fi offers us remarkably higher peak data rates. So that do 3G systems, primarily since it operates over a larger 20MHz bandwidth. In this paper we are going to survey on wi-fi technology and the standards that are followed.

Keywords: WiFi, WSE,WSM

1 . Introduction:

Wireless Stands for Wireless Fidelity. Wi-Fi is based on the IEEE 802.11 family of standards. Current Wi-Fi systems based on IEEE 802.11a/g support a peak physical-layer data rate of 54Mbps and typically provide indoor coverage over a distance of 100 feet. Today Wi-Fi becomes for last feet broadband connectivity in homes, offices, and public hotspot locations. Vic haves is the person who is called “Father of Wi-Fi”. The first wireless products were under the name WaveLan. Current Wi-Fi systems based on IEEE 802.11a/g support a peak physical-layer data rate of 54Mbps and typically provide indoor coverage over a distance of 100 feet.

2. Wi-Fi Working Concept

2.1 Radio Signals:

Radio Signals are the keys which make WiFi networking possible. These radio signals transmitted from Wi-Fi antennas are picked up by WiFi receivers such as computers and cell phones that are equipped with WiFi cards. Whenever a computer receives any of the signals within the range of a WiFi network which is usually 300 - 500 feet for antennas, the WiFi card will read the signals and thus create an internet connection between the user and the network without the use of a cord. Access points which consist of antennas and routers are the main source which transmit and receive radio waves. Antennas work stronger and have a longer radio transmission with a radius of 300-500 feet which are used in public areas while the weaker yet effective router is more suitable for homes with a radio transmission of 100-150 feet.

2.2  Wi-Fi Cards:

WiFi cards can be external or internal, if a WiFi card is not installed in our computer, we  may purchase a USB antenna attachment and have it externally connect to our USB port, or have an antenna-equipped expansion card installed directly to the computer. For laptops, this card will be a PCMCIA card in which we insert to the PCMCIA slot on the laptop.

2.3 Wi-Fi Hotspots:

A Wi-Fi hotspot is created by installing an access point to an internet connection. The access point transmits a wireless signal over a short distance . typically covering around 300 feet. When a Wi-Fi .enabled device, such as a Pocket PC, encounters a hotspot, the device can then connect to that network wirelessly.

3  Wi- fi Quality of Services

There are plans to incorporate quality of service capabilities in Wi-Fi with the adoption of the IEEE 802.11e standard. The 802.11e standard will include two operating modes, either of which can be used to improve service for voice:

 

3.1 Wi-Fi Multimedia Extensions (WME):

This uses a protocol called Enhanced Multimedia Distributed Control Access (EDCA), which is Extensions an enhanced version of the Distributed Control Function (DCF) defined in the original 802.11 MAC.

The enhanced part is that EDCA will define eight levels of access priority to the shared wireless channel. Like the original DCF, the EDCA access is a contention-based protocol that employs a set of waiting intervals and back-off timers designed to avoid collisions. However, with DCF, all stations use the same values and hence have the same priority for transmitting on the channel.

 

3.2 Wi-Fi Scheduled Multimedia (WSM):

True consistent delay services can be provided with the optional Wi-Fi Scheduled Multimedia (WSM). WSM operates like the little used Point Control Function (PCF) defined with the original 802.11 MAC.

In WSM, the access point periodically broadcasts a control message that forces all stations to treat the channel as busy and not attempt to transmit. During that period, the access point polls each station that is defined for time sensitive service.

4. Wi-Fi Standards

Standard	Data Rate	Modulation Scheme	Security	Pros/Cons & More Info
IEEE 802.11	Up to 2Mbps in the 2.4GHz band	FHSS or DSSS	WEP & WPA	This specification has been extended into 802.11b.
IEEE 802.11g (Wi-Fi)	Up to 54Mbps in the 2.4GHz band	OFDM above 20Mbps, DSSS with CCK below 20Mbps	WEP & WPA	Products that adhere to this standard are considered "Wi-Fi Certified." May replace 802.11b. Improved security enhancements over 802.11. Compatible with 802.11b. 14 channels available in the 2.4GHz band (only 11 of which can be used in the U.S. due to FCC regulations) with only three non-overlapping channels.
Bluetooth	Up to 2Mbps in the 2.45GHz band	FHSS	PPTP, SSL or VPN	No native support for IP, so it does not support TCP/IP and wireless LAN applications well. Not originally created to support wireless LANs. Best suited for connecting PDAs, cell phones and PCs in short intervals.
HiperLAN/1 (Europe)	Up to 20Mbps in the 5GHz band	CSMA/CA	Per-session encryption and individual authentication.	Only in Europe. HiperLAN is totally ad-hoc, requiring no configuration and no central controller. Doesn't provide real isochronous services. Relatively expensive to operate and maintain. No guarantee of bandwidth.

5. Conclusions

As per the above discussion there are following issues which are assumed to be the cause of the sluggish adoption of Wi-Fi technology:

·        Security Problems: Security concerns have held back Wi-Fi adoption in the corporate world. Hackers and security consultants have demonstrated how easy it can be to crack the current security technology, known as wired equivalent privacy (WEP), used in most Wi-Fi connections. A hacker can break into a Wi-Fi network using readily available materials and software.

·         Compatibility and Interpretability: One of the bigger problems with Wi-Fi is compatibility and interpretability, for example 802.11a products are not compatible with 802.11b products, due to the different operating frequencies, and 802.11a hotspots would not help a 802.11b client. Due to lack of standardization, harmonization and certification, different vendors come out with products that do not work with each other.

·         Billing Issues: Wi-Fi vendors are also looking for ways to solve the problem of back-end integration and billing that has dogged the roll-out of commercial Wi-Fi hotspots. Some of the ideas under consideration for Wi-Fi billing include per day, per hour and unlimited monthly connection fees.

·         Use this wireless networking standards chart to get quick information to help we differentiate between the available wireless networking standards and choose which standard might be the right fit for wer business. See the links below the chart for further information on wireless networking standards.