Comparison of wireless embedded technologies for real-time information system

WHO WE ARE LOOKING FOR: We are looking for an experienced developer to guide us in choosing which wireless communication type to use for a real-time exchange of data between 3-4 units over a distance of 1-100 meters. WHAT WE ARE LOOKING FOR (TO BE DELIVERED) We want a short analysis that lists which communication type to consider, along with which network type/version etc and why. This will be made into a short technical note of a few pages in Word or similar. No coding is required, but the contractor/freelancer must have practical experience with different types in order to have the know-how from a practical implementation stand-point. BACKGROUND We are currently developing a sports timer the will employ a wireless communication between an embedded micro controller (32-bit) and an iPad or other tablet. The timing itself will run on the micro controller and the iPad will be the screen and buttons (GUI) for the user. These will interact often (every few hundred milliseconds) in order to continuously verify that the connection is intact. It is important that the latency is low, and no more than 0.3 seconds. This communication will transmit about 10-30 bytes each time. The system will also need to communicate simultaneously with a thermal printer and a LED score board using the same wireless network. This communication is not time critical but the LED score board may be 100 meters (line of sight) away from the other units. OTHER INFORMATION Recommendations of OEM wireless modules are considered positive. We are currently considering Lard Technology BT900 for its small size, price point and available iOS example code. But we want advise on different bluetooth profiles. Furthermore we want this solution compared against a Wifi solution, and possibly others as well if relevant (Zigbee etc).