Pico cell radio base unit for a centralized wireless access architecture

A new concept was established by the introduction of a passive Pico cell radio base unit. This design is possible due to new discoveries and developments in fiber optics, radio frequency and wireless systems. Because the technology is optically base, it offers enhanced broadband as well as frequency and protocol independence across wireless LAN (802.11b, a, g) and cellular (GSM) signals. The heart of the passive Pico cell is the optical to radio transceiver element known as an electro absorption modulator (EAM). The EAM has an optical wave guide which transfers light from the input to the output fiber. An electric field can control (modulate) the intensity of the output light. Input light is partially absorbed or transmitted depending on the strength of the electric field. The absorbed light generates an electric current. The device acts as a photo detector and modulator simultaneously. By implementing optical wavelength division multiplexing to separate the modulation and detection process in the EAM it should be possible to achieve higher system performance. More optical power would be available allowing higher fiber or radio distances. It also significantly simplifies the processing task in the central unit.