Comparison of central and distributed control in a WDMA star network

The authors address key issues involved in data link control in a wavelength-division-multiple-access (WDMA) optical star network. A comparison is made between regulating data traffic from a central controller and at the individual distributed stations. The particular transmission format considered is one in which data are carried on a baseband signal and control information is carried on a multiplexed subcarrier, thereby providing a transparent data link without requiring a second optical control channel. It is shown that central control will relax the hardware and cost requirements of each station's receiver as well as reduce the time delay in setting up a call. The specific hardware advantages for each individual station's optoelectronic receiver when implementing a central control algorithm include a reduction in the required bandwidth and number of optical and RF filters