| 摘要 |
In an exemplary embodiment, a test signal is sent by a base station at a suitable point in a communiications protocol. According to the evaluation of the test signal transmission, a relatively high data rate or a lower more conservative data rate is selected by a mobile unit for the transmission of a relatively lengthy data message. The test signal can be associated with a query from a mobile unit having a message to send, or with a contention polling message from the base. Such test signal can be transmitted at the lower data rate where its transmission characteristics (e.g. signal strength, jitter or quality of transmission of known information) can be used to predict probable feasibility of transmission at the higher data rate, but most preferably the test signal is part of a high data rate contention poll which may alternate with a low data rate contention poll. |
