| 摘要 |
In order for a direct mode communication unit (e.g. mobile telephone), to determine the location of other communication units nearby it sends out an interrogation message at a low power level 125. Any devices which are within range to respond 120 send an acknowledgement message back to the mobile telephone. From the transmission power the message was sent with it is possible to estimate the proximity of the device. Similarly, this is repeated with varying transmission powers 135, 145 to build up a picture of local devices 130, 140. In this manner it is possible to identify a proximity of distal wireless communication units in a DMO system dynamically and relatively easily and also serves as a model to regulate and manage unsynchronised, itinerant communication systems. |
