Patent ID: 8081594

Claim:
An extension slave unit system connected with a mobile communication relay apparatus for extending a communicable area of the mobile communication relay apparatus, the extension slave unit system comprising a relay apparatus adapter connected with the mobile communication relay apparatus, and at least one extension slave unit apparatus connected with the relay apparatus adapter via a cable, wherein: the relay apparatus adapter comprises: a pilot signal generation section that repeats generating a pilot signal having a specific pattern a plurality of times; and a switching section that switches between a mode of transmitting the pilot signal generated in the pilot signal generation section to the at least one extension slave unit apparatus and a mode of transmitting a downlink signal received by the mobile communication relay apparatus to the at least one extension slave unit apparatus and transmitting an uplink signal received by the at least one extension slave unit apparatus to the mobile communication relay apparatus; and the at least one extension slave unit apparatus comprises: a reception level detection section that detects a reception level of the pilot signal or the downlink signal received via the cable; a pilot signal reception decision section that decides, upon detecting a match between a pattern of a transition of the reception level over time detected in the reception level detection section and the specific pattern, that the pilot signal has been received; a mode deciding section that decides a measurement mode when the pilot signal reception decision section decides that the pilot signal has been received, and decides an operation mode when the pilot signal reception decision section decides that a signal other than the pilot signal has been received; and a gain adjustment section that determines, when the mode deciding section decides that the mode is the measurement mode, a gain adjustment value that matches an amount of amplitude loss by the cable based on a difference between the reception level of the pilot signal detected in the reception level detection section and a predetermined reference value, and adjusts gains of the uplink signal and the downlink signal using the gain adjustment value when the mode deciding section decides that the mode is the operation mode.