An Enhanced Reliable Access Scheme for Massive IoT Applications in Ubiquitous IoT Systems

Algorithm 1

TCA in the controller.

Input: , , , , ,

Store HD or LD requests in and in ascending order of deadline

while ()

 for each: node in , develop an access scheme

  for each: channel in this time slot, if access fails, query each channel of the next time slot before the deadline

   if () then

    Priority to occupy the channel where is 0

     ; ; ;

     Delete the successfully connected node in

     for each () do; ;

     end for

    else if () then query each channel of the next time slot

   end for

   if () then return fail

  end for

while ()

  for each: node in , develop an access scheme

   for each: channel in this time slot, if access fails, query each channel of the next time slot before the deadline

    if () then

     ; ;

     Delete the successfully connected node in

     for each () do; ;

     end for

    else if () then query each channel of the next time slot

   end for

   if () then return fail

  end for

return success