WebJunction

Survey your Site

Once you have weighed the benefits and drawbacks of offering wireless internet access to patrons, the next step is to complete a survey of your library site - the building itself and the existing wired network.  When you have a good understanding of these two things, you can then decide how many and what kinds of wireless access points (and other hardware) you will need to purchase.

Know Your Building

The first step in your site survey is to take a good look at your library building.   Draw a map of your library.  (If you have architectural or construction plans, those can be helpful as well.)   If you only plan on having one or two "hotspots" in the public areas, you might not need to draw the entire library. Mapping will help you decide the best spot to place your wireless access point so that any interference or signal attenuation (weakening) is minimized.  As the wireless signal travels away from the antennae on the access point, it tends to get weaker.

Here are some important things to include on the map:

• Seating areas for patrons and staff work areas (such as the reference desk, circulation desk, information desk, and employee-only areas.)
  Remember that the goal of this entire exercise is to find the best spot for your wireless access point.  Ideally, the access point will be located in a place where the signals from the antennae can reach the patrons at the fullest possible strength and with the least interference.
   
• Library shelves and furniture
  Make sure you include measurements of any furniture (the width and height of library shelves, for example) as well as information about the material(s) they are made of. 
   
• Electrical outlets 
  Don't forget these!  Unless you select a wireless access point that uses Power over Ethernet (PoE), the access point will need a source of electrical power.  (You will usually only find PoE on high-end access points designed for large organizations.  PoE requires a special piece of equipment to be installed along with your Ethernet switch in your wiring closet.  For most libraries, the access points with PoE are overkill, but if you are interested in researching such devices, go to http://www.poweroverethernet.com for more information.)  Patrons will also appreciate having electrical outlets available to power their wireless devices.
   
• Network outlets
  While installing a wireless local area network (WLAN) segment in your library will indeed mitigate the need for new network cabling, you will still need one available wired network outlet for each wireless access point. 
   
• Other electronic devices such as cordless phones, microwaves, refrigerator and elevator motors.
  These devices can output radio signals that interfere with the radio traffic between your wireless devices and wireless access point.  This interference is called "noise" and too much noise can bring your WLAN to a standstill or at least slow it down significantly.
   
• If your library is more than one floor, locations of any elevators and stairwells should be included.

In addition to the complete layout of your proposed hotspot areas, you will want to know what the walls, ceilings, interior doors and windows of your building are constructed of.  On your site map you documented all of the permanent and movable items in your building.  It's important to know what materials they are made of in order to determine how significant the obstacles to any wireless signals might be.  Are the walls cement?  Brick?  Lead?  (OK, they probably aren't lead but you get the idea.)  Do you have metal doors?  Wire mesh in any windows?   See this Relative Attenuation of Radio Frequency Obstacles chart (http://www.intel.com/business/bss/infrastructure/wireless/deployment/considerations.htm#relative) for a list of common obstructions found in many buildings and the degree of signal attenuation they cause.  The fewer the obstacles between the wireless access point and WLAN users, the better.

When you are satisfied that your building map is fairly complete, examine it closely to see where a wireless access point should be placed.  The typical signal range of 802.11b and g access points is about 150 feet in "ideal" conditions (no physical obstacles or signal interference) but that distance can decrease by as much as half depending on your building layout. 

When you identify a potential location for an access point, place it on your map and draw a 100 ft. radius around it.  What sort of obstacles (furniture, walls, shelving) fall within that radius?  If there are none, great!  You've found the spot.  If there are objects in the way, ideally those objects should be those that cause low attenuation.  If the obstacles are paper, metal, concrete or mirrors, just know that the signal could possibly stop dead when it meets those obstacles and any devices on the other side of them won't have service.  In a small library, it is highly unlikely that you will find a 100 ft. radius with no obstacles whatsoever.  That's understandable.  You are simply trying to find the spot that will offer the best possible signal given your building's layout.  If most of the public seating areas fall within the middle of the radius, you will probably be able to provide them with a reliable signal.

It is important to decide from the beginning whether or not you are attempting to cover your entire building with wireless access or you are only aiming to provide a hotspot in a public area. Obviously, it will be much simpler to just provide wireless access in one area of the building with one access point than it will with many separate areas needing coverage.  However, if you determine that you need to cover the entire building, it IS possible, just a little more challenging (and expensive).