| 摘要 |
In a cellular telecommunication network, the distance between a base station 8 and a mobile unit 15 is measured and is used to determine the call charge. The distance between the base station 8 and the mobile unit 15 may be computed by comparing transmitted and received signal strength or by measuring the time taken by a test signal to travel between the mobile unit 15 and the base unit 8. An area within a predetermined distance 14 of the base station may be designated a cheap call rate zone 13 and a mobile unit 15 found to be within this area may be charged at a lower call rate. Means may be provided to inform the mobile unit 15 that it is within the cheap call rate zone 13 and the distance computation may be carried out at the base station 8 or mobile unit 15. By inducing the subscriber to make calls close to the base station 8 the power required to support a call is kept to a minimum, thereby reducing the likelihood of interference in nearby cells and extending the battery life of the unit 15. More efficient re-use of communication signal frequencies in close proximity to a base station is also facilitated. |
