摘要 |
A portable radio telephone (5) communicates with base stations (1, 2) in a digital radio telephone system, such as DECT, employing TDMA transmission. The portable radio telephone is programmed with an algorithm which is operative to select a communication channel by storing a blind slot mask (7) representative of the time slots in each frame which are excluded, either by virtue of being occupied by the base station or by the portable radio telephone itself. Hence, any channel attempted and failed in an occupied time slot is excluded and marked blind in the blind slot mask. Further, the algorithm is operative to check the time slots for availability in a predetermined sequence which corresponds to the temporal sequence of the slots (or the reverse thereof) to promote orderly filling of the time slots at the base stations.
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