Tag Archives: ssid

Seg 4: Experimental analysis-2

(4) set up wifi hot spot: Since there is no other wifi hot spot in our such experimental environment, then we use OUR HTC mobile phone to set up a wifi hot spot (wifi router is suitable). After this, temperature data can be sent by wifi to the cloud. At first, opent the “WLAN hot spot” in the mobile phone. At the same time, remember to open 3G network signal, which can make temperature data collected by LM35 send to server in the remote cloud. In this experiment, the WLAN hot spot name in my phone is set as “HTCtest” for the mobile SSID, and password is “12345678″. You can also use the default name and password. However, for the input convenience, you had better to modify the default name and password.

(5) network configuration: When the computer connects the wifi network wifi HI_LINK_0021 successfully, you can input the website “″ in the browser, and input the user name and password (both are “admin”) to configure the web data, which is shown in Figure 3-5.

Figure 3-5 Network data configuration

When configure the network data parameters, please note that the marked by red rectangle, and others can be default set. Some notes are given as follows.

  1. At this time, wifi module can be viewed as a collection and transmission unite, which can send the collected temperature data to the server on the remote distributed cloud.
  2. SSID and Password are denoted by the SSID and Password of the mobile phone (or wifi router).
  3. Remote ServerDomian/IP: It is pointed to the server IP address where the temperature data are stored at.
  4. Locale/Remote Port: the server port number.

After configure, click “Apply”. At this time, if you check your phone, there is a “1 user connects” in the bottom of the “WLAN hot spot”. This implies that, the wifi module on the Arduino board has been connected the mobile hot spot. That is, the wifi module has been connected the internet.

Seg 4: wifi architectures

As for 2.4GHz, there are 14 channels. Each has 22MHz bandwidth, which is shown in Figure 1-3. Evidently, only channel 1,6,11 are the channels which are not intertwined each other.

Figure 1-3 wireless channel

  1. Wi-Fi architecture

    Figure 1-4 Infra networks

    Wi-Fi has two main modes: Infra and Adhoc networks

    1. Infra networks
      1. Minimum element: BSS (Basic Service Set), shown in Figure 1-4.
  • One or more radio hosts;
  • AP: Access Point, i.e., BS (Base Station)
  • Radio hosts communicate with the outside by AP
  • Inter-connection among APs by the inter-connection with Hub/Switch /Router
  1. SSID (Service Set Identification)
  • Manager assigns a SSID less than 32 bytes for an AP;
  • A BSS can exist lonely. It can also be connected to another BSS by the connection with DS (Distribution System) for the constitution of ESS.
  1. ESS (Extension Service Set)

ESS is composed of several APs and DS. All of the APs share an ESSID, and an ESS can include several BSS, as shown in Figure 1-5.

Figure 1-5 ESS

  1. DS (Distribution System)
  • Distribution System, which is used to the logical connection BSS, and provide the roam distribution system for the wireless APs.
  • When DS is used, then all of the BSSes seem like a BSS in a BSS.
  • DS is usually denoted by Ethernet, point-to-point link or other wireless networks.
  1. Adhoc networks
  • No AP center control
  • Generally no connection to the outside networks

Figure 1-6 Adhoc networks