When dealing with wireless sensor networks, there are a lot of factors that affect the quality and reliability of transmission signals between your sensors and the gateway.
Position your Wireless Gateway in a central location
Whenever possible, position your wireless gateway in a central location within your facility. If the gateway is against an outside wall, the signal will be weak on the opposite side of your building.
Position your Wireless Gateway off the floor and away from walls or metal objects.
Floors, walls and metal structures such as heating ducts and file cabinets, interfere with your sensor network's wireless signals. By avoiding these structural "Signal Killers" when placing your wireless gateway and sensors, you can ensure optimal performance of your network.
Reduce wireless interference.
If you have cordless phones or other wireless electronics in your facility, your gateway might not be able to "hear" your sensors over the noise from the other wireless devices. To quiet the noise, avoid wireless electronics that use the 900MHz frequency. Instead, look for cordless phones that use the 5.8GHz or 2.4GHz frequencies.