T-MMB is much better than foreign T-DMB and DAB-IP systems in compatibility, frequency band utilization, complexity, power consumption, service management and interactive service. Another advantage of T-MMB is that it supports a very large frequency range, from 30MHz to 3000MHz. T-MMB mobile TV system has perfect operation and management platform, signing right and billing system, and the network structure of the system is shown in figure 1.
Figure 1: System network structure diagram
At present, many members of WorldDMB attach great importance to T-MMB, and think that T-MMB system has the strength and may become the global mainstream standard. Many academicians of China Academy of Sciences and China Academy of Engineering agreed that the T-MMB technology of New Shoreline Company has reached the international advanced level and is a powerful tool to unify the layout of DAB multi-standards, which is superior to other standards of DAB system, making China standard the global mainstream standard for the first time.
T-MMB R&D follows the same industrial route as Korean-European T-DMB, BT and Microsoft DAB-IP, that is, it inherits, innovates, catches up and leads again based on the international advanced level and mature and solid industrialization foundation. At present, T-MMB from transmission to reception, including baseband processor chip, has been guaranteed in stock, and passed the field high-power test, and has been commercialized by the end of 2006.
T-MMB innovation
T-MMB has made innovations in the following three aspects:
1. Channel frame structure, channel coding and modulation
2. Reuse configuration information
3. Component signal transmission interface
Main technical characteristics of T-MMB
get along well with
T-MMB system is fully compatible with DAB, DAB-IP, T-DMB and other standards. In T-MMB, DAB/T-DMB/DAB-IP signals are all independent subchannels, and operators can choose them flexibly according to the actual situation.
High spectral efficiency
In order to improve the spectrum efficiency of the system and transmit more programs in a limited bandwidth, T-MMB not only supports DQPSK modulation, but also supports high-order modulation modes such as 8DPSK, 16DAPSK. In addition, T-MMB adopts a single LDPC error-correcting code and does not need concatenated outer codes, so compared with the concatenated code schemes in DAB-IP and T-DMB, the spectral efficiency of the system is further improved. Combining the above two gains, the spectral efficiency of T-MMB is twice that of DAB.
LDPC error correction coding technology
In order to ensure the good reception performance of the system in high-speed mobile environment when using high-order modulation mode, after considering the influence of performance, complexity, implementation platform and other factors, the advanced channel error correction coding technology-LDPC code is introduced into the T-MMB system.
System test results
In August, 2006, under the arrangement of Radio, Film and Television Science and Technology Department, the T-MMB system completed the high-power function test in Beijing. The test conclusions are as follows:
1)T-MMB system is compatible with DAB/T-DMB.
2) High speed mobile reception supported by the system
3) The coverage radius of T-MMB system with 8DPSK and 1/2LDPC is equivalent to that of DAB.
Industrialization status quo
The compatibility of T-MMB system with international standards was considered at the beginning of design, with the aim of utilizing mature and reliable equipment systems, network facilities and mature industrial chains. T-MMB is a multimedia broadcasting system based on DAB. After more than ten years of operation, DAB has been proved to be reliable. As long as the software of multiplexer, transmitter and receiving chip of DAB system is upgraded, T-MMB system can be formed. Therefore, T-MMB has a good industrial foundation, simple implementation and easy popularization, and has the following industrial advantages: ready-made network facilities and frequency resources; Inherit DAB's mature industrial base and operating experience for more than ten years; Operators can rely on the mature product technology and industrial chain of DAB technology; High spectrum efficiency can create huge benefits for operators.