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WLAN în locuințele personale
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The user who has Internet connection in their single-family house, usually would like to have possibility of using the Internet in various parts of the home or even in its close surroundings such as the garage or garden. To reach that goal, the perfect solution is use of a wireless network (WLAN) operating in 802.11b/g or the latest n standard.
In the case of difficulty with building cable installation, the wireless network can also solve the problem with connection of a greater number of household computers to the global network. Depending on the way of providing the Internet to the house, there may be used different variants of installations.
Variant I - Internet provided by a cable television operator via cable modem with Ethernet output, or by a local ISP using Ethernet cable.
In these cases we need a router with WAN input in the form of RJ-45 Ethernet port, e.g.:
  • Wireless xDSL Router: TP-Link TL-WR340G N2952,
  • High Power Wireless USB Adapter: TP-Link TL-WN422G N2921,
  • PCI Network Interface Card: TP-Link TF-3239DL 10/100 Mbps N2999.
These devices allow to connect 4 computers (using Ethernet patch cables) and up to a dozen other computers - using wireless connection.
The cable from the ISP is connected to WAN port (Internet); we connect the first computers to the ports of the switch (with patch cables). The rest of the computers have to be equipped with wireless cards allowing connection to the access point built into the device.
Access Point: Linksys WRT54GL (4p-switch &router, 2.4 GHz, 54Mbps)
Internet access via Ethernet cable
Variant II - Internet access via ADSL technology

We should use:
ADSL modem integrated with access point and switch:
or ADSL modem integrated with switch:
  • TP-Link TD-8840 N2905
  • TP-Link TD-8840B N2906 (Annex B)
  • TP-Link TD-8841 N2908
The computers are connected as described above, depending on the kind of the device (with AP or without AP).
Wireless ADSL2+ Router (Annex A): TP-Link TD-W8910G <br />(4p switch, eXtended Range AP)
Internet access via ADSL technology
Variant III - Internet provided wirelessly with the use of the set: directional antenna and wireless card in the computer.
At least two devices have to be used. Firstly, we have to connect access point working in AP Client mode to a directional antenna.
To operate at 5GHz we should use:
The Ethernet output has to be connected to a wireless router:
As the final result we will get the situation similar to the first example.
Access Point: WA2204C (AP/APC 54Mbps)Access Point: Linksys WRT54GL (4p-switch &router, 2.4 GHz, 54Mbps)
Wireless access to the Internet
Variant IV - wireless access. Some Access Points have been fitted with a very useful function named Wireless Routing Client, which enables us to configure wireless port as WAN port that is normally found in any router. It means that the wireless connection can be shared with built-in router by its LAN ports. The advantage of such configuration is compactness - one piece of equipment that performs the role of two devices. The solution allows to create our own configurable subnetwork that can be well protected from unauthorized access.
Devices with Wireless Routing Client function:
Due to dual-band radio transceiver, Compex WP54AG N2520 can be used as Wireless Routing Client in both frequency bands: 2.4 and 5 GHz.
Access Point: Compex WP54AG (802.11a/b/g; 2.4 &5 GHz DUAL BAND; 2x LAN - PoE)- CLEARANCE SALE!
AP Compex WP54AG in Wireless Routing Client mode
What is the router needed for?
Internet service providers usually assign only one IP address to a user. If the user wants to connect a greater number of computers, he may either ask the provider for additional addresses (it usually means additional costs), or use a router with address translation feature - NAT.
Application of such a router is often the best solution. Basic configuration of the router consists in setting WAN address received from the ISP, changing the default passwords, if needed - setting MAC address for WAN port (WAN MAC clone option), and defining local address - the address of the gate for the rest of home network computers. It is also required to configure access point: to choose appropriate channel, to set SSID, encryption of transmission (the best is WPA) and to assign passwords. Various models offer different additional functions which may be used by more advanced users.
Where to place the access point?
The place an access point is situated strongly influences the range of home network within a house and its surroundings. An overall rule of radio network functioning in rooms says that a signal has usually useful level after it passes through 3 walls or 2 ceilings.
So, it may be optimal to place the access point in the location where the wireless network is used most often (i.e. drawing room, study or ... bedroom). If we want to use Internet in the whole house, it is better to place the AP in the geometrical center of the house. However, if we also want to cover the garden, the device should be placed nearby the appropriate window. In that situation there is a risk that the signal will be low in some more distant rooms. Generally, it is impossible to estimate the range and level of the signal in some place without tests. Only tests in the actual environment can help to find optimum solution.
If we do wish to cover the whole house and garden, but the location of the access point nearby a window doesn't bring appropriate effect, we can try to do some trick with two antennas.
Why do some devices have two antennas?
Some wireless devices are equipped with two stub antennas. The device equipped with two antennas uses them in specific way to improve quality of transmission. It is so called collective reception (diversity).
It consists in checking by the receiver which antenna provides stronger signal, and only that signal passes for further processing. The same antenna is then chosen to send the data. Advantages coming from the use of that mode will be perceptible mainly indoors - in rooms - where radio waves are being reflected many times by walls, appliances, and people. When receiver has only one antenna, it may happen that radio wave coming to it will be overlaid on the other wave which was reflected and came to the receiver with some delay, traveling longer way. This situation may cause signal fades and drop of bandwidth. When the device has two antennas, if the signal fades out in one antenna, there is a chance that the other antenna will receive it much better and the transmission will be retained.
It should be remarked here again that the access point checks every time which antenna receives stronger signal, and only this antenna is active, so it is impossible to use them as two independent antennas. However, the property described above allows us to improve home network operation. Reverting to the example, when we want to cover the whole house and garden, we should place the access point in the central point of the hose. We connect original stub antenna to one antenna output which will serve the home needs, and we also should connect a panel antenna (e.g. ATK-P1 - A7130 with appropriate cable) to the second antenna output.
We direct the antenna to the outside of the house or install it nearby the window facing the garden. With this configuration, we have possibility of using wireless network at home or in the garden. According to what has been written above, it won't be possible to serve two wireless clients simultaneously - one at home and the other in the garden, because the access point has to choose whether to use stub antenna or panel antenna. This kind of operation would be very unstable. Anyway, a few wireless clients inside the house can work simultaneously, because all of them are served by the same antenna. Similarly, there shouldn't be any problem with serving a group of wireless clients in the garden.
How to configure wireless cards?
Configuration of wireless cards isn't difficult task. Following the instructions from the manual we will install the right drivers. Then it is needed to setup correct IP address, gateway (of our router), infrastructure mode, SSID of access point, coding keys. Choosing the cards, we should pay attention to the encryption methods - whether they are the same as those of the access point. There are available cards with the older WEP, or with WEP and more advanced WPA encryption. If the cards and the access point support WPA it is recommended to use that kind of encryption.
And what about ad-hoc mode?
Wireless cards can also work in the mode ensuring direct connection between them, without any use of access point. If you use Internet on a single desktop computer, and occasionally you would like to have possibility to connect your laptop with wireless card, the cheapest solution is installation of a wireless card in the desktop computer. You should configure it to ad-hoc mode, assign adequate SSID, coding keys, appropriate IP address (from the other class then the IP assigned by ISP). Then you configure the same way the wireless card in the laptop, and you run on the desktop "internet connection sharing" or any application working as software router. This way you have built a simple wireless network at very little cost. Disadvantage of the solution is only the fact that the desktop PC must be turned on when you need internet connection on your laptop.
Wireless ADSL2+ Router (Annex A): TP-Link TD-W8910G <br />(4p switch, eXtended Range AP)
Example of application
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