The base station structure, an Access point

1. The base station structure

The first and most important step is design of a transmitting base station. At this stage of designing it is important:

• approximate how many recipients will use this network, and determine what kind of receiver they will use (PCI or PCMCIA wireless cards, USB devices or Access Points).
• Take lenghts between a base station and a receiver into consideration
• Take into account a necessity of Power supply for all the devices and a necessity of supply with the internet
• Take into account the height of mounting the transmiter (the higher doesn’t mean the best)

The second step of network designing is a choice of data transmition devices. It will be described in the charter named „Access Point”. Choosing the devices it is necessary to take work modes ( Access Point configuration) into consideration. It is worth to consider what a mode use to get an expected effect.

The next step is a connection set with an Internet provider by the Internet gate. The gate provides all computers in a LAN network with the Internet. The gate can be a computer which access points are connected to by a swith. In this case the gate transmits data packets, it can also authorizes users (e.g. by the MAC addresses), sets IP numbers (DHCP) etc. On the gate can be included a firewall, network management software and the full range of another services.

2. Access Point

Access points are the wireless devices which clients can use for gain access to the Internet. In our case access points allow gain access to the gate. Depending on an WLAN size, to the gate one or more access points can be connected .

In practice the number of clients connected to the access point is limited. This number is limited by a channel capacity which we plan to guarantee. Moreover the lots of devices with a big number of wireless clients, which cause a big load, connected. Networks like this has inclinations for suspensions and it can impair the network reliability.

In case when each wireless client device connects a few new clients (e.g. house) to a WLAN network, it is no sense to connect more than 8 devices to one access point (D-link DWL 900AP+). If a device connects a single client, the number of wireless clients can be increase.

During an Access points configuration should take into consideration for channel settings. It is necessary to have a minimum 3-channel spacing between channels from devices covering the same area (e.g. 1, 5, 9, 13).

An Access point selection depends on a requested functionality. If a basis of network operating is to give access to the internet for a big quantity of people, where a complex management is not necessary, and there aren’t a big quantity of client devices – it is not necessary to invest in expensive devices.

An another situation is if it is necessary to join a lot of LAN networks by Access points, where a reliability and security is required. In this case it needs to use expensive devices. Investing in a professional equipment we get abilities to packets filtering, which is very usable in big networks. It allows for limit a traffic generated by a Windows messenger.

It is the best if an access point is nearby an antenna, we can avoid a signal loss in a joining cable. Devices can be mounted into hermetic, plastic enclosures (available in offer). The devices are operating well in extremal weather conditions (including a frost). There are special devices dedicated to outdoor applications.

In some areas there can be a problem with a power supply. We encourage to use an original power supplier, we don’t encourage you to lengthening a cable between a device and power pack. The mains voltage drops can cause unstable device operating.