Transport Applications - tetra

Synchronous Data Manager –How it works• Optimised polling– Polling avoids random access collisions – 100% channel uplink v. 37%under normal circumstances– Synchronous access is achieved by sending a status message askingfor “slot granting”. 20-byte data is sent with the ACK reply to this statusmessage• Multiple secondary control channels (SCCH)/base station- increases capacity• Synchronisation of control channels• Definition of new commands – to manage sequential & cyclical polling lists• SDM is based on the controlled use of a portion of the control channel toavoid the “avalanche” of random access radio collisions