Abstract: Packets are transmitted from an apparatus to another apparatus via a plurality of carrier waves. The apparatus calculates, for each of the plurality of carrier waves, a tolerance parameter indicating a tolerable margin of the current line-quality value for causing a change of a modulation method to be used, based on a line-quality value received from the another apparatus, and allocates packets to the plurality of carrier waves based on a service-quality level assigned to each of the packets and the tolerance parameter calculated for each of the plurality of carrier waves, such that a first packet having the service-quality level equal to or higher than a second packet is allocated, on a priority basis, to a first carrier wave having the tolerance parameter equal to or larger than a second carrier wave to which the second packet is allocated.

Abstract: Packets are transmitted from an apparatus to another apparatus via a plurality of carrier waves. The apparatus calculates, for each of the plurality of carrier waves, a tolerance parameter indicating a tolerable margin of the current line-quality value for causing a change of a modulation method to be used, based on a line-quality value received from the another apparatus, and allocates packets to the plurality of carrier waves based on a service-quality level assigned to each of the packets and the tolerance parameter calculated for each of the plurality of carrier waves, such that a first packet having the service-quality level equal to or higher than a second packet is allocated, on a priority basis, to a first carrier wave having the tolerance parameter equal to or larger than a second carrier wave to which the second packet is allocated.

Abstract: A method is used to switch a channel which is used for a communication between a transmitting end and a receiving end from a main channel to a protection channel. The method of the present invention allows automatic compensation for the loss caused by the switching of the channel to the protection channel. Furthermore, the level difference of the baseband signal outputs from each of the main channels can be automatically controlled to zero regardless of the main channel from which the channel is switched to the protection channel.