Teachings presented herein offer reduced and stable computational complexity for symbol block detection using multi-stage assistance, and also provide for the generation of soft bit values. The device for controlling current of an LED adjusts current supplied to the current amplifier using a SEL input without an effect of a noise, thereby making it possible to change the current of the LED without separately changing a resistor. This method allows obtaining low-dimensional features with observed quantum effect such as quantum layers, dots and superlattices. Each blade outputs serial data streams with in-band control information in multiple stripes to the switching fabric.