Jianping An

A novel method of channel estimation for DRM system

A novel method of channel estimation adaptable to DRM system is proposed. According to the characterization of the OFDM parameter and pilot pattern defined in DRM standard [ETSI ES, 2003-04], channel estimation has to be done first in time and then in frequency direction. Linear interpolation filter is used in time direction, and windowed DFT channel estimation is used in frequency direction. Simulation results show this method has better performance with low computation complexity.

Rejection of narrowband interference in DS-SS systems employing decision feedback filters

The performance of direct-sequence spread spectrum systems in the present of narrowband interference rejection is studied employing decision feedback filters. Closed-form analytical expressions for the systems performance are derived. Both analysis results and numerical simulation results show that DF filters outperform linear prediction filters by comparison.

Channel Estimation in MIMO-OFDM Systems by Tracking the Delay-Subspace

A time domain channel estimation method in MIMO- OFDM systems by tracking the delay-subspace is proposed. The time impulse response is estimated by transmitting known pilot symbols, and the estimation performance is improved by the Givens rotation based delay-subspace tracking and amplitudes tracking based on the LMS filtering. The simulations prove that the time domain channel estimation by tracking the delay- subspace can track faster fading channels, and is more accurate with low complexity.

The Design Scheme of the Baseband Part of an OFDM Transmitter for Video Transmitting

OFDM is the key technique in the next generation communication. In this paper, we describe the design and implementation scheme of the baseband part of multimedia transmitting system carried by automobile. It is developed with the COFDM technique and MPEG-4 standard. The baseband system is composed of source encoder, channel encoder, OFDM modulator and pre-distortion set. The equipment designed can transmit audio/video signal at a wireless mobile channel and build an exclusive wideband LAN for some special users. It supplies a convenient user interface and modular function design process, which are implemented by the universal high performance chips-DSP, FPGA and EPLD. Based on the theory of software defined radio, the software embedded in the chips can be programmed to different functions. So it is easy to debug and modify for designers with a much lower cost

A novel active queue management scheme based on self-similar traffic rate estimation

In this paper, we firstly propose self-similar traffic rate estimating algorithm PLMA for active queue management scheme to regulate packet marking probability. This algorithm improves the availability of the rate estimation algorithm under the self-similar traffic condition. Then, we design a robust AQM mechanism based on rate estimated by the PLMA, which enable router to be more responsive to various traffic characteristics. The simulation results show that performance of proposed AQM algorithm is better than the other algorithms.