Call setup for a mobile packet data dispatch network

摘要

A proactive speculation method decreases the call setup time for private calls (200) and selective dynamic group calls (300). In a push-to-talk dispatch network (40) an originating mobile unit (10) sends a wake-up packet (54, 114) to the dispatch network (40). Prior to initiating the push-to-talk function, the target mobile units (20-30) receive a wake-up packet (68, 146-148) from network (40). Thereby, prior to establishing the push-to-talk function, each of the mobile units in the push-to-talk call have been coupled via RF links. If the originating mobile unit has a current IP address, direct wake-up packets (72) may be sent.