Basic WLAN Communication

Communication plays a vital role in human life. Today wireless devices dominate the communication methods. A wireless device works in a wireless network. A wireless local area network (WLAN) provides network communication using wireless technologies. The IEEE 802.11 task group defines the standard, which defines the wireless mode of functioning. It functions in 2.4 (ISM) or 5 GHZ wireless band. Each band is divided in multiple set of channels. On 2.4 GHZ band these channels are separated by 5MHZ spacing. However on 5GHZ band the spacing between the channels is 20 MHZ. It’s normally an extension of the wired network and gives user the mobility while being connected to the network.

The device which provides the wireless connectivity is referred to as the Access Point (AP). The region serviced by the AP is referred to as Basic Service Set (BSS) and is defined as a set of Stations (STA) connected to the AP, including the AP. The area serviced by the AP is dependent on the range of the antenna of the AP and is referred to as the Basic Service Area (BSA). The Service Set Id (SSID) and Basic Service Set ID (BSSID) identify each service region of an AP. SSID is a basically a 32 character string of human readable characters used to identify the service region. However multiple AP’s can have the same SSID and hence is used in combination with BSSID to uniquely identify the AP. BSSID is basically the MAC address, which is designated to the AP. The software development company India working to provide these solutions is emerging as the chosen destinations for business opportunities.

Let us have a broad overview of the basic working of connection process in wireless networking. These forms a part of embedded solutions. The APs in a network indicate the presence of their BSS by doing periodic advertisements via special frames referred to as Beacons. Whenever a STA needs to connect to an AP, it initiates a scan. Scan is basically a mechanism to detect the APs and involves moving on enabled channels on a particular band and looking for APs. It can either send special frames expecting a response from all APs to indicate the presence of their BSS, referred to as active scan. The other way to detect the APs, is to wait on each channel for some specific duration looking for the advertisement frames from the AP, referred to as passive scanning.

Once the desired AP is detected, the next process is to establish a connection with the AP using special frames for the same. Once the connection is established and non-mandatory authentication, the STA is connected to the network and can access all the accessible services on the network provided by the service provider. The AP component on your WLAN enabled DSL modems and the WLAN STA on your laptop use the same mechanism to connect. Once connected, you can access the internet services, provided by the service provider, from your laptop. Since wireless communication is susceptible to eaves-dropping, forgery related attacks, the IEEE standard also defines mechanism for encryption and protection against such attacks. The companies with expertise in providing embedded system solutions look for the issue and follow the set guidelines.