Yangang Li

Embedded Transmission of Multi-Service Over DTMB System

To efficiently support the transmission of terrestrial and mobile services within the same spectrum over the Digital Television Terrestrial Multimedia Broadcasting (DTMB) system, a flexible multi-service datacasting scheme in a backward compatible manner is proposed. Using this scheme, the conventional DTMB receivers work as usual by simply selecting the specific terrestrial DTV programs on the basis of the package identifier (PID) checking, while only the desired mobile service data are processed by the mobile receivers via the designed control signals. Both theoretical analysis and computer simulation show that, at acceptable spectral efficiency penalty, the proposed method not only supports the embedded transmission of multi-services with no reception performance degradation for the traditional terrestrial broadcasting service, but also flexibly provides much better mobile reception performance.

Interference Elimination for Chinese DTMB System With Transmit Diversity

When adopting transmit diversity in the Chinese digital television terrestrial broadcasting (DTTB) system, there exists two kinds of interference: training sequences (TSs) from different transmit antennas are overlapped; and the TSs are interfered with OFDM data due to multipath fading. In order to distinguish different TSs, this paper proposes a method to design orthogonal TS set, which also have good correlation characteristic. Subsequently, an iterative algorithm to eliminate the interference between TSs and data is proposed and theoretically analyzed. Finally, simulations are performed and the results show that the system with the proposed scheme can achieve great diversity gain under acceptable computational complexity.

The novel approach to support multimedia services over DTMB system

In the conventional digital television terrestrial multimedia broadcasting (DTMB) systems, all the transport streams (TS) from various programs are multiplexed in the level of TS packets, which have the same interleaving, constellation mapping, channel coding, and thus the same quality of service (QoS). Moreover, due to the convolutional interleaving mode, the receivers have to be turned on all the time to obtain the designated data until all the received signals are de-interleaved. In this paper, for DTMB systems, the concept of the physical sub-channel (PSC) in time-frequency domain is proposed, and the scheme to support services with different QoS requirements is also addressed. Based on these techniques, a novel approach to support multimedia services over DTMB systems in a backward compatible manner is proposed and evaluated by computer simulations.

Novel Multi-Service Datacasting Scheme over DTMB System

To efficiently accommodate the terrestrial broadcasting service and the mobile service within the same spectrum over Chinese Digital Television Terrestrial Multimedia Broadcasting (DTMB) system, a novel multi-service datacasting scheme in a backward compatible manner is proposed in this paper. In this scheme, an equivalent QAM (E-QAM) mapping method is adopted for mobile services. Moreover, to reduce the impact of the larger peak to average power ratio (PAPR)caused by the E-QAM, a random constellation extension (RCE)technique is further proposed. Both theoretical analysis and computer simulation show that this scheme not only supports the normal reception of the traditional terrestrial broadcasting service in DTMB receivers, but also provides better mobile reception performance at acceptable spectral efficiency penalty.