Abstract: A controller (112) monitors (306) delivery of two-way outbound messages to a plurality of portable messaging units (122), and records (308) reliability statistics (238) for the two-way outbound messages as a function of delivery parameters. The controller also determines (316) a target transmission reliability for sending a message; and estimates (318), from the reliability statistics, the required delivery parameters for sending the message at the target transmission reliability. The controller then transmits (320) the message in accordance with the required delivery parameters.
Abstract: A communication network (200, 300) stores (502) location information for the communication network. A portable device (100) determines (504) whether the portable device is in motion. The portable device requests (510) the location information only when the portable device determines itself not to be in motion. The network sends (512) the location information to the portable device, in response to the request for the location information from the portable unit.