Parameter of Allocation Slot Length should not be too large for waste of time waiting.
According to
//the length of an allocation slot is equal to pAllocationSlotMin + L × pAllocationSlotResolution
#define pAllocationSlotMin 500 //500 μs for NB PHY
#define pAllocationSlotResolution 500 //500 μs for NB PHY
#define allocationSlotLength 3 //for NB PHY, L=3 means that 2 ms per slot
#define allocationSlotLength2ms ((pAllocationSlotMin + allocationSlotLength*pAllocationSlotResolution) * 0.001) //2 ms default
Parameter of Allocation Slot Length should not be too large for waste of time waiting. According to
2 ms is too long for small packets.