Development of an Optical Signal-Based IPS from an MCU-SoC

In this work, we have studied the integration of an optical signal-based Indoor Positioning System (IPS) capable of supporting multi-access discrimination techniques. The research analyzes the different techniques and conditions that can be used to develop an IPS using a microcontroller unit (MCU)-based system-on-chip (SoC) systems. The main goal is to be able to integrate into the MCU both the hardware and software requirements for an IPS detector. In this way, different strategies that can implement multi-access discrimination using Frequency-division multiple access (FDMA) have been tested, such as I/Q demodulation, digital filtering, and discrete Fourier transform (DFT). This analysis has found a good technique to be executed in an MCU-based SoC, the DFT implemented through the Goertzel’s algorithm. The empirical tests carried out concluded that, using only one an MCU with the required HW and tuned SW, 15 position measurements per second were computed, with high accuracy in the 3-D positioning, with errors of less than 1 cm in a test area of 3.5 × 3.5 m 2 . The main contribution of the paper is the implementation of the optical signal based IPS in an MCU-SoC that includes signal acquisition and processing. The digital filtering or spectral processing for up to 16 received signals makes this IPS system very attractive from a design and cost point of view.

Multiple Access Acquisition Technique Based on CAZAC Sequences in OFDM System

The sliding correlation acquisition technique, which is based on CAZAC sequences in OFDM time-domain multiple access, is proposed and verified. This technique takes advantage of the characteristics of good auto-correlation and cross-correlation characteristics of CAZAC sequences in time domain and achieves the purpose of multiple access discrimination by the different correlation peaks. Whats more, this technique can increase acquisition performance by multiple frames adding up in a receiver according to the receivers demand. The simulation in AWGN channel shows that the technique is feasible and effective in time-domain signal acquisition in OFDM system.