ABSTRACT
Orthogonal frequency-division multiplexing (OFDM) is an effective modulation scheme by encoding the digital data on multiple orthogonal subcarriers. The OFDM technique has been widely applied in wireless communication systems since it performs well in reducing the intersymbol-interference when data rate is high. The orthogonality of OFDM signal is usually implemented with fast Fourier transform (FFT) algorithm. Inverse FFT is applied on the sender side to generate orthogonal subcarriers and FFT is applied on the receiver side for the demodulation. Since the complex indoor environments commonly have many obstacles, multipath reflections are considered as one of the major factors degrading the communication performance. The channel impulse response is estimated by combined deterministic and modified Monte Carlo method, where the line-of-sight and first three reflections are considered to simulate the impulse response of the channel. OFDM is used in the positioning system to achieve high positioning accuracy.
