Radioville¡¯s In-building IF Distributed Repeater System (IBS 2040) can offer technical solutions for congestion and coverage problems in high-rise buildings and shadowed areas reducing the excessive burden of investment in the introduction of Optical Distributed Repeater System. It can be easily installed and equipped in the large buildings such as offices, shopping malls, department stores, and stations to cover shadowed service area inside those buildings. While it is perfectly harmonized with in-building appearance, and applicable to buildings where transmission of maximum 300m is needed. This system is consisting of Donor Unit (DU) and Remote Antenna Unit (RAU). For the effective coverage of in-building shadowed service area, one DU can be connected to 8 RAUs, and also can be extended to 32 RAUs using Extender Unit. Electric power for RAU is supplied through the RF transmitting coaxial cable from DU, and the power loss from distributor and coaxial cable can be automatically compensated up to 35dB by Auto Gain Control (AGC) function, thus all of the outputs of RAU are kept same level. DU and RAU is connected with coaxial cable utilizing the low-loss feature of IF band. This system is the only practicable and economical solution to ensure a proper quality of service for in-buildings.