Multiuser Detection for Sensing Asynchronous LED Illumination Contributions

Multiuser Detection for Sensing Asynchronous LED Illumination Contributions

Liu, D.

Leus, G. (mentor)
Van der Veen, A. (mentor)

Electrical Engineering, Mathematics and Computer Science

Telecommunications

2010-04-22

In recent years, light-emitting diodes (LEDs) have played an increasingly more important role for light illumination. Beyond the basic function of pure illumination via intensity control of xed color light, LED technology additionally allows control over the light color and illumination pattern. In order to realize these functions of intelligent lighting control, we need to estimate the light intensity of each LED in the sensor location. To this end, a synchronous code-time division multiple access - pulse width modulation (CTDMA-PWM) system has been proposed for LED identification and simultaneous measurement of illumination strength. However, this system strictly requires perfect synchronization, which in practice is not easy to be guaranteed. Therefore, in this thesis, we propose an asynchronous CTDMA-PWM scheme and corresponding multiuser detection algorithm to combat the multiple access interference (MAI) caused by asynchronous multiple access. We explore the algorithm of conventional minimum mean square error (MMSE) linear estimation and implement it iteratively in a blind way without the knowledge of channel input from interfering LEDs.

multiuser detection
code time division multiple access (CDMA)
asynchronous multiple access
mean square error estimation (MMSE)
blind MMSE
imaging diversity.

http://resolver.tudelft.nl/uuid:5807b5d0-73c8-4258-9016-5f5d3ae7785d

2010-04-24

Student theses

master thesis

(c) 2010 Liu, D.