A radio frequency (RF) site survey is the first step in the deployment of a Wireless Network and the most important step to ensure desired operation. A site survey is a task-by-task process by which the surveyor studies the facility to understand the RF behaviour, discovers RF coverage areas, checks for RF interference and determines the appropriate placement of Wireless devices. We will use this site survey as the basis for the RF design and will guarantee the functionality and underwrite any project where an onsite RF survey is conducted by its personnel.
An onsite RF survey provides detailed information that addresses coverage, interference sources, equipment placement, power considerations and wiring requirements. The site survey documentation serves as a guide for network design, for the installation and verification of the Wireless communication infrastructure.
There are two major categories of conducting an onsite RF survey which include:
Physical Site Survey - Is an examination of the physical environment in which the WLAN will operate, this is inclusive of the physical premises and the location for the antenna placement or cable runs. The primary objective is to ensure that the location can accommodate a WLAN.
RF Manual Site Survey - The RF survey is the process of examining the current RF activity and utilisation in the physical space where the WLAN must operate. Additionally, it involves evaluating how the new WLAN will function within the environment.
The actual process of performing a wireless site survey involves many steps. The Manual site survey requires the traditional method of a WLAN engineer conducting both a physical and RF survey onsite where WLAN coverage is required. The engineer will place one or more APs at strategic locations and walks throughout the intended service area using an advanced surveying tool to test signal strength, signal to noise ratio, channel interference and data rate. Manual surveys are the most accurate form of surveying for WLAN coverage, as AP locations are based actual RF information in the intended coverage area. As a result guesswork and theorised analysis is removed from the RF planning.
In a Wireless network, many issues can arise which can prevent the radio frequency (RF) signal from reaching all parts of the facility. Examples of RF issues include multi-path distortion, hidden node problems, and near/far issues. By conducting a site survey we identify the regions where these issues can occur. A site survey helps define the contours of RF coverage in a particular facility. It also helps us to discover regions where multipath distortion can occur, areas where RF interference is high and find solutions to eliminate such issues. A site survey that determines the RF coverage area in a facility also helps to choose the number of Wireless devices that are required to meet its business requirements.
When conducting an RF wireless site survey, there are three main focuses, to ensure a reliable and scalable wireless network is provisioned:
- Survey for Coverage – Provide blanket coverage throughout the desired areas with a minimum signal strength or data rate.
- Survey for Capacity – To ensure the wireless network provides sufficient bandwidth for the anticipated number of users and in particular to provide scope for high density of users.
- Application Support – Ensure that the wireless network supports all predicted applications that the client wishes to use on the wireless network, this includes Wireless VoIP, radio frequency identification (RFID) and data applications.