Abstract: In one embodiment a system is provided for multirate communications allowing for different data rates for each data unit on a channel, including both data units from different mobile units and from the same mobile unit. A sending unit preferably begins by determining the rate at which to start communications, and monitors, for example by use of an RSSI detector, for an indication that the rate should be changed. A rate adjustor implements the change, and can make changes as frequently as every data unit. The encoder applies the appropriate rate and inserts a rate indicator indicative of the data or encoding rate, and sends the data unit. On receiving data units, the receiving unit first determines the rate for each data unit or group of units, then appropriately decodes the data unit(s). As a result, the actual data throughput can be adjusted to permit optimized throughput.

Abstract: A method and apparatus for accessing a communication system relies on the use of varying access probabilities for subscribers or messages of varying priority. A serving infrastructure entity (e.g., a base station) determines access probabilities (e.g., p.sub.hi and p.sub.lo where there are two classes of subscribers) in response to known system parameters like the current rate of access attempts for each priority class of user/message. Values representative of these access probabilities are then transmitted to the subscriber unit(s), for example by use of a system broadcast channel or control channels. These values are then used by the subscriber units in determining when to access an uplink channel. A temporal and/or proportional priority distribution approach is preferably used in determining the access values. As a result of this contention-based prioritization, an expedited access is achieved by higher priority units/traffic, thus increasing their throughput.