COWS

Coherent Optical Wireless Systems for Next Generation Home and Corporate Networks

 

 

The COWS project will investigate the potential of coherent detection as a means to improve coverage, mobility and data rate of indoor optical wireless systems. These will enable optical wireless technology to overcome some of its shortcomings and claim its position as one of the cornerstones of the future internet. The poor link budget of conventional intensity modulation/direct detection optical wireless systems necessitates the existence of a line-of-sight path between the transmitter and the receiver. This renders the link susceptible to obstacles such as people moving around the room, furniture, etc thereby reducing network coverage and limiting user mobility. Coherent detection provides an inherent receiver gain and can therefore be used in order to detect signals carried by optical beams that do not follow a line-of-sight path but reach the receiver through multiple reflections from the walls or the ceiling of the room (diffuse propagation regime). COWS aims at providing a proof of concept of the applicability coherent detection in  diffuse optical wireless systems. It will address several implementation issues, including channel equalization through orthogonal frequency domain multiplexing (OFDM), coding, digital signal processing circuit design, component and wavelength choice, multiple input multiple output (MIMO) and diversity schemes. The ultimate goal of COWS is to assess the potential of such techniques as the cornerstones of future high speed wireless networks that will be able to support gigabit-per-second data rates with WiFi-like mobility and coverage.