Information Technology Blog

On this day (towards the end of 2000), wireless Internet technology alternatives that need to be calculated by telkom & operator Indosat. Today telkom 2Mbps lease line its worth Rp. 10 million / month - when using wireless Internet equipment on the market, we can operate the channel speed 11Mbps with investment of Rp. 20 million-a licensed frequency for the cost of about Rp 2 million per year-an. Even on this more and more WARNET in various cities (Bandung, Medan, Jogya etc.) start to build networks between WARNET its use technologies are wireless. Not to mention the inclusion of various satellite operator (also wireless) Internet stage in Indonesia, such as Pacific Satellite Nusantara (PSN), Melesat (from Infocom), PalapaNet (from Satelindo), TelkomNet Turbo (from Telkom) add flare wireless Internet infrastructure in India - the ultimately enable us to build the cheaper Internet access for the people of Indonesia.

Key equipment required is a WaveLAN card on the day that is generally shaped like PCMCIA cards appear in the image on the side. In the picture card ORINICO made by Lucent, who works at a frequency of 2.4GHz speed 11Mbps IEEE 802.11b protocol using the dimodulasi use CDMA (Code Division Multiple Access) so that the frequency of the same work several channels at once.


If there are problems in the link, do Orinoco akan speed automatically fallback to 5.5Mbps, 2Mbps & 1 Mbps in order to keep good performance. Orinoco follow standard WECA (Wireless Ethernet Compatibility Alliance) Wi-Fi 'wireless fidelity' standard. Scattered power from the card-WaveLAN card is usually very low only about 25mW.


To increase the distance to reach the required emission WaveLAN external antenna (which is placed outside the building). Generally, for the distance-distance 5-10 km can be achieved by using external antenna tersebut.Masalah major-general, card because it is powerless wavelan low around 25 MW-an, the distance between the antenna card wavelan it can not be too far so that the signal does not lost in the coax cable connecting the card with the antenna wavelan
it. Usually connecting cable (50 ohm coax as well), limited to less than 10 meters distance. So do not surprised if we see akan computer (PC) in the roof letakan WARNET-WARNET the related media wavelan use this, because it would not be in the PC letakan in the roof so that the distance between the antenna to the card can be created in under 10 may be minimal meters.

After WaveLAN Card & Antenna is wrong, the next strategy is to find out how we can use the PC that many dipasaran to be able to function as a router. Usually when we buy a card in wavelan provide software drivers for its Windows operating system. Sialnya if Windows is not good to use for the Internet router in the network, different from both the UNIX Linux & FreeBSD much better for applications in the Internet router. On this router we pair two (2) network interface, which is a form of card wavelan 2-11Mbps for long distance communication are another form of ethernet card to connect local area network (LAN) from WARNET, school or the local office in the building / room

Art is how to persuade the ISP to connect so that we are willing to be associated with WaveLAN. Some ISPs are willing to be happy to connect using the WaveLAN, but some ISPs, especially from the telecommunications monopoly that is not willing to connect with WaveLAN. The problem is actually only a problem licensing frequency & to pay the ISP for access to dedicated high-speed 24 hours.


Viscera Broadband Wireless Internet Access

WLAN technology 2.4GHz, 5.8GHz, 5GHz is growing rapidly, especially because the exemption permits the frequency bands in the ISM band and UNII (Unlicensed National Information Infrastructure) by the United States government. Data communications standard that is generally used IEEE 802.11 family, IEEE 802.11b which has a maximum speed of 11Mbps, while the IEEE 802.11a has a maximum speed of 54Mbps.

Few descriptions of IEEE 802.11a technology works on the 5GHz akan seems to be the future of technology, high-speed Internet world. One of the breakthrough technology that happens is done by Radiata www.radiata.com that build the chip set that consists of a modem-based band (R-M11a) and a transceiver (R-RF5) in the 5GHz UNII band is based on IEEE 802.11a, especially created for anticipate that in the WLAN market estimasikan reach U.S. $ 5.6 billion in 2004 by Cahners In-Stats Group. How much it costs? Chipset R-M11a baseband modem & R-RF5 radio transceiver that can work up to 54Mbps is worth U.S. $ 35 in the amount of 100,000 units. Is still in the raft must be packaged in a PCMCIA for use in computers, fell to its per PCMCIA card could reach U.S. $ 200-3000 / card.

In the IEEE 802.11b is currently a lot of use 2.4GHz band for Bluetooth and HomeRF equipment widely used technology uses spread spectrum technology, Direct Sequence Spread Spectrum (DSSS) and hoping Frequency Spread Spectrum (FHSS) technique is a part of the access-based Code Division Multiple Access ( CDMA).

Unlike the IEEE 802.11b is now widely used, in the IEEE 802.11a modulation techniques used Coded Orthogonal Frequency Division Multiplexing (COFDM), which enables us to obtain such a connection is no different with cable connection in the indoor environment (in space).

Baseband modem is compliant with the IEEE 802.11a standard is usually implemented with the path transmits & receive the same once independent, allowing for simultaneous operation in full duplex. Alternative modulation BPSK, QPSK, 16-QAM & 64-QAM is possible to work at various speeds as well as the obligatory circumcision based on IEEE 802.11a. Power used is very low with the work on the 2.5V voltage.

Equipment 5GHz UNII band transceiver based on IEEE 802.11a standard was developed that usually have a wide dynamic range with minimal components that may be. Use of external filter is reduced by the use of mixer and on-chip filters, which in turn reduces the cost of the system. Receiver (Rx) is linear with the bypass switch to the Low Noise Amplifier (LNA). Noise figure receiver (Rx) around 6dB, power transmitter (Tx) of the chip 0dBm (can be reinforced if needed), 20MHz IF Filter, Programmable 70dB Rx gain control, 60 dB Programmable TX power control.