Single frequency net system and its synchronous system and method in mobile multimedia broadcast

Abstract

The invention provides a single frequency network system in mobile multimedia broadcasting and a synchronous system and a synchronous method thereof; the synchronous system comprises a multiplex code stream interface and an isochronous controller and also comprises a multiplex code stream load subpackaging device, a payload filter and a first annular cache unit; the multiplex code stream load subpackaging device is used for receiving multiplex code stream, separating multiplex frame data packets from the multiplex code stream and sending the multiplex frame data packets to the payload filter; the payload filter is used for filtering out filling data in the multiplex frame data packets and sending the multiplex frame data to the first annular cache unit; the first annular cache unit is divided into blocks; a serial number of each block respectively corresponds to the unit of the second of the time stamp included in the multiplex frame code stream; the first annular cache unit is used for storing the multiplex frame data. The invention can cope with the accidental errors of single frequency network data transmission or the intermission of data transmission and well realizes the establishment of a single frequency network.

Description

technical field [0001] The invention relates to the technical field of mobile multimedia broadcasting, in particular to a single frequency network system, a synchronization system and a synchronization method thereof. Background technique [0002] As one of the networking methods of terrestrial digital TV, SFN is widely used all over the world. A Single Frequency Network (SFN) is composed of a number of synchronous transmitting stations in different locations, which transmit the same signal at the same time and at the same frequency to achieve reliable coverage of a certain service area. It is very different from the technology of Multi-Frequency Network (MFN). The technology of Multi-Frequency Network is that the same digital TV program is sent by different TV channels; and the "translator" (translator) realizes the TV Channel switching. [0003] Compared with the multi-frequency network, the SFN has the following advantages: [0004] The first advantage of SFN is that i...

AI Technical Summary

Problems solved by technology

[0013] a) Occasional errors (packet loss, wrong packet) in SFN data transmission can easily cause second misalignment of SFN, resulting in the failure of SFN establishment

The so-called second misalignment means that since the single frequency network requires each transmitter to transmit the same signal at the same time, if one of the transmitters loses packets or wrong packets for one second or several seconds, the transmitter will be in the wrong position. Time transmits data, resulting in second misalignment (that is, there is a time difference between the time of data transmitted by the transmitter and the time it is scheduled to be sent out), resulting in that each transmitter of the single frequency network cannot transmit the same signal at the same time, that is, synchronization cannot be achieved

[0014] b) Interruption of single frequency network data transmission will cause the transmitter to generate a single frequency signal, which is easy to damage the back-end power amplifier

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