Use of Repeater for range extension.

• It is often necessary provide the dedicated coverage of cellular mobile system. For hard-to-reach areas, such as within building or in valley and tunnels.
• The radio Transmitter known as repeaters, are often used to provide such range extension capabilities. Therepeaters are bidirectional in nature.
• They simultaneously send signal to and receive signals from base station.
• The repeater work using air signals so that they may be installed anywhere and are capable of repeating and entire cellular and personal communication (PCS) band.
• The repeaters amplifiers and reradiates the base signal, to the specific coverage region after receiving signals from a base station forward link.
• At the same time, the receiver noise and interreference are also radiated by the repeater on both the forward and reverse link.
• Therefore, we must take care proper care to place the repeater properly and to adjust various forward and reverse link amplifier levels and antenna pattern properly.
• In practice the directional antennas or distributed antenna systems (DAS) are connected to the inputs or outputs of repeaters for localized for spot coverage, particularly tunnels and buildings.
• The repeaters do not add capacity to cellular system, but it simply serves to radiate the base station signals into specific locations.
• The repeater is increasingly used to provide coverage into and around buildings, where coverage has been traditionally weak.