Patent ID: 8190105
Filing Date: 2012-05-29
Classification: H04B,H04L

Abstract:
1. A modulation mode switching method in a point-to-point radio communication system in which a modulation mode to be used can be switched among n types of modulation modes and a radio transmission line has a redundant configuration of an active system and a standby system, the modulation mode switching method comprising: a step of setting in advance one of a transmission-quality-priority operational form and a transmission-capacity-priority operational form; a step of setting in advance (n−1) types of lower-limit thresholds used for switching to a modulation mode direction of a system gain increasing direction and (n−1) types of upper-limit thresholds used for switching to a modulation mode direction of a system gain decreasing direction; a step of comparing each of reception levels of a radio transmission line of the active system and a radio transmission line of the standby system with each of the lower-limit thresholds in a different order for each of the operational forms; a step of comparing each of reception levels of a radio transmission line of the active system and a radio transmission line of the standby system with each of the upper-limit thresholds in a different order for each of the operational forms; and adaptively controlling switching among the n types of modulation modes on a switching condition in accordance with purport of the operation form based on a result of each of the comparisons.