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Less is more
TUFTS of wires are a constant source of nuisance, causing problems vis-a-vis mobility and also making the office look rather untidy. However, wireless networking is developing at a breakneck pace, and in time, such issues will be resolved.
There are a number of different wireless technologies available, some of which include HomeRF, BlueTooth, Zigbee, HyperLan, 802.11, 802.11b, WiFi, 802.11a, 802.11g and IrDA. Confused by all the technical jargon? Well, continue reading and you’ll feel a little less befuddled.
Let’s begin with HomeRF, a wireless networking technology that supports both voice and data transmission. It is designed for consumer applications such as wireless home networks, communication between Personal Digital Assistants (PDAs) and laptops, and other such similar uses.
It operates in the same 2.4GHz unlicensed Industrial, Scientific, and Medical (ISM) band of the electromagnetic spectrum. The original HomeRF specification has data transfer rates up to 1.6Mbps. HomeRF2 and HomeRF3 boast of speeds up to 10Mbps and 22Mbps, respectively. In contrast to the competing 802.11 wireless networking technologies that use Direct Sequence Spread Spectrum (DSSS) radio transmission, HomeRF employs Frequency Hopping Spread Spectrum (FHSS) transmission.
BlueTooth
BlueTooth is a wireless networking technology that promises to provide a simple, low-cost method of linking together cellular phones with headsets, PDAs with printers. Bluetooth is based on base-band, FM transmission, using frequencies between 2.4 and 2.4835GHz within the unlicensed 2.4GHz ISM band.
Bluetooth divides this band of frequencies into 79 separate channels and there are 1,600 frequency hops per second. It’s data transmission rate is 1Mbps, but practical maximum transmission rate is more like 780Kbps or lower with a maximum range of transmission of 33 feet (10 metres). Bluetooth supports concurrent connections of up to eight devices, forming what is called “piconet.”
BlueTooth is finding its place in many areas. However, only time will tell, whether a BlueTooth- enabled can of coke will someday communicate with a refrigerator, “asking” it to lower the temperature for just the right taste.
ZigBee
ZigBee technology is a low data rate, power consumption and lowcost wireless networking protocol targeted towards automation and remote control applications supporting 254 client nodes along with one fully functional device (master).
The technology can operate in any one of the three bands — the ISM band at 2.4GHz worldwide, the European 868 MHz band and the US 915MHz ISM band. The data rate at 2.4GHz is 250 kbps. For lower bands, it is 20 kbps and 40 kbps respectively. The nominal range is 10 to 75 metres. With ZigBee technology, packets are small and infrequent, so the probability of interference is very low.
As far as the choice between BlueTooth and ZigBee is concerned, we need both technologies because BlueTooth focuses towards voice applications and higher data rate applications (cell phones, headsets, etc).
ZigBee is more appropriate for control applications, which do not require high data rates, but must have low power, low costs and ease of use (remote controls, home automation, etc).
HiperLAN/2
HiperLAN/2 is a global standard for broadband wireless networking. It is an alternative to the existing 802.11a, high-speed wireless networking standard developed by the Institute of Electrical and Electronics Engineers (IEEE).
HiperLAN/2 provides raw data transfer speeds of up to 54Mbps, which corresponds to roughly 20Mbps actual, sustained throughput. Instead of operating in a slower, crowded 2.5GHz ISM frequency band, HiperLAN/2 uses the higher 5GHz frequency band for greater throughput.
It employs Orthogonal Frequency Division Multiplexing (OFDM) at the PHY layer to support high, data transfer rates.
802.11: This is a set of IEEE standards designed to do, for wireless networking, what the 802.3 standards have done for Ethernet.The current standards ratified under 802.11 are:
802.11: The original wireless networking standard supporting data rates of up to 2Mbps and now superseded by 802.11b. It employs both DSSS and FHSS physical-layer transmission methods and allows data to be transmitted at either 1Mbps or 2Mbps
802.11b: A standard, for wireless networking, supporting data rates of up to 11Mbps and operating in the unlicensed 2.4 GHz ISM band. 802.11b transmission is standardized on DSSS.
WiFi
A seal of approval from the Wireless Ethernet Compatibility Alliance (WECA) certifying that wireless networking devices such as access points and network cards are fully compliant with the 802.11b wireless networking standard.
802.11a: A standard which supports higher data rates of up to 54Mbps and operates in the 5GHz Unlicensed National Information Infrastructure (UNII) band. 802.11a transmission is similarly standardized on DSSS.
802.11g: It is the most recent draft based on the 802.11 standard that describes data transfer rates equally as fast as 802.11a and boasts backward compatibility to 802.11b, required to make inexpensive upgrades possible. 802.11g compliant devices utilize OFDM modulation technology.
Of these standards, 802.11b is currently the most widely deployed, with support from over 20 vendors. The 802.11a standard is newer and is seen as the next generation for wireless technology. All these standards use the same MAC method, CSMA/CA, to allow multiple users to share a single communication channel. Note that this is not the MAC method used by Ethernet (it uses CSMA/CD), so it is a misnomer to call 802.11 technology wireless Ethernet.
Infrared Data Association (IrDA)
IrDA is not a standard like Bluetooth, HomeRF and the 802.11 series of standards; rather it is an organization. The intent was to create an inter-operable, low-cost, low-power, half-duplex, data interconnection standard that supports a walk-up, point-to-point user model that is adaptable to a wide range of computer devices.
IRDA devices have a data rate of 4Mbps at close range but the typical data rate is about 115kbps which is good for exchanging data between handheld devices. IR networks do not interfere with spread spectrum RF networks. The security of IR devices is inherently excellent because a hacker or eavesdropper will have to directly intercept the beam in order to gain access to the information being transferred.
Wireless technology, as mentioned earlier is still in the process of evolving. Despite the fact that there are some drawbacks to this technology, one cannot deny that wireless networks are certainly more reliable and faster than the current networks in use. It is only a matter of tim before the glitches in wireless technology are smoothed out, making it the most sought after, dominant networking force available.
The writer
Now you hear me, now you don’t
1. Wireless signals are not as reliable as most of us are led to believe. In fact, signals often tend to “fade” or “cut” in places such as underground car parks, mountainous terrains and dense forests. Complaints of dropped calls and interference from other radio and electronic devices are quite common.
2. Privacy is a major concern when it comes to wireless networks. Studies suggest that analog wireless calls are more likely to be picked up by radio waves or electronic signals and it is not uncommon to overhear someone else’s conversation during your phone call.
3. Some wireless plans turn out to be much more expensive than wireline plans. If a user does not use all his/her minutes, chances are that he/she will lose the unused minutes after a certain period of time.
4. The quality of wireless service is dependent on tower placement. Most towers of the network need to be strategically placed so that wireless signals can travel smoothly. Not only this but also, these towers interfere with the natural landscape of an area. As compared to this, wireline networks run across the country, buried underground.
5. Wireless customer service can be highly unreliable at times. It can be extremely difficult to get through the numbers provided for the complaint centre/customer service centre. The reason is that this service is provided on a regional or national basis and so it usually takes longer to get through a customer service representative.
6. Different wireless service carriers provide various levels of service and so you just might experience problems when you try to make calls on another carrier, some of which include network and connection problems and bad reception.
7. Finally, most wireless plans impose heavy penalties for early contract termination. Thus, it’s always a good idea to go through the terms and conditions of the service provider or you’ll be in for a rude shock, if you decide to discontinue your plan before the term of the contract ends.— Sci-tech World Report
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