Method and device for auto-gain control of mobile digital multimedia broadcast

Abstract

The invention relates to the field of mobile digital multimedia broadcasting, in particular to an automatic gain control technology for the mobile digital multimedia broadcasting. The embodiment of the invention provides an automatic gain control method and device for the mobile digital multimedia broadcasting used for improving the receiving effect of the mobile digital multimedia broadcasting. The invention carries out periodic adjustment on the average power of received signals according to an automatic gain control period in each appointed time slot of the mobile digital multimedia broadcasting, and which detects the average power of the receiving signals according to a signal power detecting period in each automatic gain control period; furthermore, when the average power detecting value of the last receiving signal is greater than the maximum value of a target range in the automatic gain control period, the average power of the receiving signals is reduced and when the last detecting value in the automatic gain control period is less than the minimum value of the target range, the average power of the receiving signals is increased. The automatic gain control period, the target range and the signal power detecting period are confirmed according to the qualities of the received signals.

Description

technical field [0001] The invention relates to the field of mobile digital multimedia broadcasting, in particular to an automatic gain control technology of mobile digital multimedia broadcasting. Background technique [0002] Mobile digital multimedia broadcasting is a broadcasting system covering a wide range of user terminals. Through satellite and terrestrial wireless broadcasting, it provides small screen, small size, mobile and portable user terminals, such as mobile phones, personal digital assistants (Personal Digital Assistant, PDA), MP3, MP4, digital cameras, notebook computers, etc., receive multimedia broadcasting programs and information services anytime and anywhere. [0003] China Mobile Multimedia Broadcasting (CMMB) is a technical standard for mobile digital multimedia broadcasting proposed by China. The following takes the CMMB system as an example to introduce the receiving system of mobile digital multimedia broadcasting. The length of a radio frame in ...

AI Technical Summary

Problems solved by technology

[0005] If the automatic gain control is performed in all time slots according to the existing technology, then in the non-designated time slots when the system is closed, since the received signal is 0 when the system is closed, the average power of the received signal will continuously increase under the action of the automatic gain control In some cases, the value of the automatic gain control is out of control; and when the adjustment step of the automatic gain control (Step) is relatively small, the adjustment of the automatic gain control cannot keep up with the fast fading signal changes in the fast fading channel, and when the automatic gain control When the Step is relatively large, the accuracy of the automatic gain control will be relatively poor.

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