Help select wireless technology - low latency (ANT? BLE?)

[marmotteNZ]

Dear all,
I want to select the best wireless technologies (BLE? ANT? Sub-1Ghz?) and sensor’s uC type to implement the following project:

A wireless sensors network with a star topology. One “Master” with typically 8/10 sensors, up to 15 is desirable.

• The main technical objective is to achieve at the very least a message rate of 20 per second / per sensor, with also a latency as short as possible (50ms is a worst case.5 to 10ms are desirable). The actual data load of each message doesn’t need to be huge. 8bits sufficient, 16 bits would be better.

• 
  The main technical objective is to achieve at the very least a message rate of 20 per second / per sensor, with also a latency as short as possible (50ms is a worst case.5 to 10ms are desirable). The actual data load of each message doesn’t need to be huge. 8bits sufficient, 16 bits would be better.

• The main technical objective is to achieve at the very least a message rate of 20 per second / per sensor, with also a latency as short as possible (50ms is a worst case.5 to 10ms are desirable). The actual data load of each message doesn’t need to be huge. 8bits sufficient, 16 bits would be better.

• Battery life, for the sensors, is a key element too. With one coin cell (2032?) several hours of wake (measurements with the message rate specified above) are required (more is better), and “sleep” battery life needs to be good also.

• The uC doesn’t need to do much more than read the actual sensor outputs (digital) and transmit them with the specified rate. It may have to do some averaging if the sensor’s readings are faster than the message rate, and otherwise:
  Read and transmit battery level at wake/sleep
  Manage a sleep/wake cycle depending of what is received from the Master (and of the battery level)

• Cost for the sensor parts is also a very important objective.

• Cost and battery life for the Master module is not so important.

• Ease of implementation matters, as well as not having huge licensing costs!

Any advice would be highly appreciated. I have started looking at ANT but I’m not sure if it is really the best implementation.
Thanks

 

[(*steve*)]

For predictable latency you would need to use a polling or possibly token passing system