Weiqiang Liang

A Robust and Adaptive Carrier Recovery Method for Chinese DTTB Receiver

This paper presents a robust and adaptive carrier recovery method for Chinese digital terrestrial television broadcasting (DTTB) system in which pilot signal and pseudonoise (PN) sequence are adopted to help carrier recovery. The conventional methods utilize pilot or PN sequence respectively. In this paper, we try to combine the advantage of each method together and propose a well designed state machine to control system state automatically. Moreover, as for using PN sequence, a fine PN tracking state is introduced to ensure the robustness of the proposed method. Software simulations show that the proposed method can provide large acquisition range, short acquisition time and small tracking jitter in severely distorted static and dynamic channels. Lab tests and field trials also prove its good performance in real propagation environments.

Error rotated decision feedback equalizer for Chinese DTTB Receiver

In this paper, an error rotated decision feedback equalizer (DFE) based on the minimum-mean-square error (MMSE) criterion is proposed for Chinese DTTB Receiver. When the DFE is complex, the length of it is large and the convergence algorithm is least mean square (LMS), the residual carrier frequency error and the phase noise from tuner will seriously weaken the performance of DFE. As an adaptive filter, the DFE will respond to the variation of phase error. Furthermore, it is difficult to estimate the phase error when the other factors of channel distortion exist. The proposed DFE has properly solved these problems. Analysis and simulation show that not only phase noise can be estimated and nicely compensated but also DFE will not be interfered by the phase error. So the performance of DFE is improved.

Combined NR Decoding With Decision Feedback Equalizer for Chinese DTTB Receiver

In this paper, the effect of the Minimum-Mean-Square Error Decision Feedback Equalizer (MMSE-DFE) when combined with decoding that is applied to the coded transmission, is studied. When the length of MMSE-DFE is large, it is more realizable to use the decoding value as the decision value. Here, the DFE using the Nordstrom-Robinson (NR) decoding value is proposed. Through simulation and by testing results, the DFE combined with NR decoding shows better performance than the traditional DFE. Moreover, this paper supports an approach to cancel partial residual Inter-Symbol Interference (ISI) that is caused by decision delay when DFE is combined with NR decoding.

Joint channel estimation and equalization algorithm for DTMB receivers

This paper presents a joint channel estimation and equalization algorithm for Chinese Digital Terrestrial Multimedia Broadcasting (DTMB) system. The initial channel estimation is carried out using PN sequence, then the frame header (FH) is eliminated from the received data and the frame body (FB) is obtained. After a one-tap frequency domain equalizer, the equalized data is fed into a proposed tracking loop to refine the channel estimation. Simulation results have proved the good performance in both static and dynamic propagation environments for DTMB receivers.

An improved carrier recovery method in multi-path fading channels for DTMB receivers

This paper presents an improved carrier recovery method for Chinese Digital Terrestrial Multimedia Broadcasting (DTMB) system especially in multi-path channels. The conventional methods are mostly derived from the AWGN channel model. In the real propagation environment, multi-path distortions are much more common, which may result the conventional carrier recovery loop locked at an undesired point. In this paper, an improved method using as many as observations of carrier frequency offset in one frame is introduced to reduce the estimated variances. Lab tests and Field trials have proved that it can dramatically reduce the probability of fake lock in real propagation environments.

Terrestrial Television Broadcasting in China: Technologies and Applications

This chapter will discuss the two main terrestrial television broadcasting systems widely used in China. One is the China Terrestrial Television Broadcasting (CTTB) standard which is named as “Frame structure, channel coding and modulation for digital television terrestrial broadcasting system”. It was issued in August 2006 as a mandatory standard for traditional terrestrial broadcasting and had been put into execution from August 2007. The other is China Multimedia Mobile Broadcasting (CMMB) which is a mobile television and multimedia standard developed and specified by the State Administration of Radio, Film and Television (SARFT). Based on the statellite and terrestrial interactive multiservice infrastructure (STiMi), it is a mixed satellite and terrestrial wireless broadcasting system designed to provide audio, video and data service for handheld receivers with less than 7 inch wide LCD display.