KR100908487B1 - Improvement of Channel Search Reception Sensitivity for Digital Multimedia Broadcasting (DMX) Receivers - Google Patents

Abstract

The present invention relates to a method for improving channel search reception sensitivity of a DMB receiver. Even when a full channel scan cannot fully decode a fast information channel (FIC), the ensemble channel information of a standard channel information table collected in advance is provided. It is to be able to receive a broadcast signal by using.

To this end, the present invention provides (a1) a first step of checking whether a valid broadcast signal is received in a selected frequency band when a full channel search is selected, and (a2) ensemble channel information parsed from a stream of a valid broadcast signal currently being received. (A3) when the parsed ensemble channel information is normal, store it as channel information of a corresponding frequency band, and collect in advance when the parsed ensemble channel information does not exist or is abnormal. It provides a method for improving the channel search reception sensitivity of the DMB receiver, comprising the third step of reading the ensemble channel information of the standard channel information table and storing the channel information of the corresponding frequency band. To be able.

DMB, receiver, channel search, reception sensitivity, improvement

Description

Method for improving of channel scan receive sensitivity in digital multimedia broadcasting receiver

1 is an operation flowchart illustrating a channel search algorithm using a sequential fast information channel (FIC) full channel scan method performed by a frequency band in a general DMB receiver;

2 is a block diagram schematically illustrating an internal configuration of a general DMB receiver;

3 is an operation flowchart illustrating a channel search reception sensitivity improvement algorithm of a digital multimedia broadcasting (DMB) receiver according to an embodiment of the present invention;

FIG. 4 is a flowchart illustrating a process of retrieving ensemble channel information backed up from a standard channel information table in the algorithm of FIG. 3.

<Explanation of symbols for the main parts of the drawings>

10: high frequency (RF) tuner 20: OFDM channel decoder

30: location information receiver 40: A / V decoder

50: nonvolatile memory 60: program memory

70: Audio Codec 80: Video Encoder

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for improving channel search reception sensitivity when receiving Digital Multimedia Broadcasting (hereinafter, referred to as 'DMB'), and more particularly, to a radio frequency (RF) in a DMB receiver. Prior to receiving a broadcast signal through a tuner, Orthogonal Frequency Division Multiplexing (hereinafter, referred to as 'OFDM') channel reception in a sequential channel search (full scan) by frequency band performed by a channel decoder The present invention relates to a method for improving the channel search reception sensitivity of a DMB receiver to improve the sensitivity.

Digital multimedia broadcasting (DMB) broadly encompasses all broadcasting such as European video DMB (DVB-T, DVB-S), European audio DMB (DAB-T, DAB-S), data broadcasting and cable broadcasting. Generally, it is limited to terrestrial DMB and satellite DMB in Korea, and digital mobile broadcasting DAB and PMSB (Personal Mobile Satellite Broadcasting), which is a part of MMB (Mobile Multimedia Broadcasting) business of telecommunications operators, are facing the era of broadcasting and telecommunication convergence. It has been integrated into multimedia broadcasting focused on video, audio and data services, and has evolved into terrestrial DMB and satellite DMB.

The broadcasting structure of the EUREKA-147 system, which is generally used for DMB (or DAB), is a service that is digitally modulated on one frequency, unlike AM / FM broadcasting, which transmits one broadcast on one frequency. As a method of simultaneously transmitting a plurality of service components, the ensemble structure of the EUREKA-147 system includes a fast information block including various information related to services. FIC (Fast Information Channel), which consists of a sub-element, and FIG. (Fast Information Group) and sub-elements thereof, and an MSC (Main Service Channel) composed of a bundle of sub-channels. Is done.

In the EUREKA-147 system, the display of service data such as an ensemble, a service, a service component, a program type (PTY) through fast information channel (FIC) parsing is a function required for a DMB receiver. Is one of.

This ensemble, service and service component of the EUREKA-147 system uses a frequency manual input broadcast selection in which a user directly inputs a frequency to detect a signal or a frequency auto-scan scheme similar to FM / AM broadcasting. The DMB receiver can effectively use the searched ensembles, services, service components, PTYs, and the like to allow a listener to effectively select and listen to a desired broadcast.

On the other hand, before receiving a broadcast signal from the high frequency tuner, the DMB receiver checks the receivable channel information (or channel name) through the sequential fast information channel (FIC) search for each frequency band in the OFDM channel decoder. The channel search reception sensitivity is one of important characteristics in the DMB receiver because the broadcast cannot be seen if the channel information (or channel name) is not found during the FIC search even if the actual broadcast signal is received during the lock status check.

FIG. 1 is an operation flowchart illustrating a channel search reception algorithm using a sequential fast information channel (FIC) full channel scan method performed in a general DMB receiver, and shows an effective broadcast in a frequency band selected for full channel search. Checking whether a signal is present through a high-frequency tuner, and obtaining ensemble channel information parsed from a stream of an effective broadcast signal from an OFDM channel decoder to determine whether it is normal ensemble channel information, and if the result is normal ensemble channel information. And storing ensemble channel information of the corresponding frequency band in a memory, and such a channel searching operation is programmed to be repeatedly performed until the last frequency band.

The high frequency tuner mounted on the DMB receiver generally cannot receive channel signals of different frequency bands while receiving channel signals of one frequency band. It is determined whether there is a signal.

The lock status check sensitivity of the high frequency tuner is better than the channel decoding sensitivity of an OFDM channel decoder searching for a fast information channel (FIC).

Therefore, according to the conventional channel reception method, even if the RF tuner determines that there is a valid broadcast signal, the orthogonal frequency division multi-channel decoder often fails to fully decode the FIC for a predetermined time. It is a factor that reduces the reception sensitivity of the DMB receiver.

Accordingly, the present invention has been made to solve the above problems, and the present invention is a standard channel information table that is backed up in memory in advance even when the FIC is not fully decoded during a full channel scan. It is an object of the present invention to provide a method for improving the channel search reception sensitivity of a digital multimedia broadcasting (DMB) receiver to improve the channel search reception sensitivity of a DMB receiver by receiving a broadcast signal using the ensemble channel information.

A feature of the present invention for achieving the above object is a method for improving the sensitivity during full channel scan in a DMB receiver having a high frequency tuner, an OFDM channel decoder and a location information receiver, (a1) Determining whether a full channel search is selected, and if a full channel search is selected, a first step of confirming whether a valid broadcast signal is received in a frequency band selected for a full channel scan by the high frequency tuner; When the valid broadcast signal is found as a result of the first step, parsing the ensemble channel information from the stream of the valid broadcast signal currently received from the OFDM channel decoder to determine whether the ensemble channel information is present or not and whether it is normal or abnormal. In the second step and (a3) when the parsed ensemble channel information is normal as a result of the determination of the second step, the parsed ensemble channel information is used as a corresponding frequency band. Stored as channel information, and if the parsed ensemble channel information does not exist or is not normal ensemble channel information, the ensemble is backed up according to the current position information and the frequency information from the standard channel information table previously stored in the memory. The third step of reading the channel information and storing the channel information of the corresponding frequency band is a channel search reception sensitivity improvement method of the DMB receiver.

These objects, features and advantages of the present invention will be more readily understood by reference to the accompanying drawings and the following detailed description.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation of the preferred embodiment of the present invention.

2 is a block diagram schematically illustrating an internal configuration of a DMB receiver according to the present invention, in which a high frequency tuner 10 receiving a broadcast signal in a frequency band selected for full channel search and an effective broadcast received by the high frequency tuner OFDM channel decoder 20 for parsing ensemble channel information in a stream of signals, and location information for receiving location information such as location information from an external location information signal, ie, location information from a navigation station or local information directly from a broadcasting station, through an antenna. A non-volatile memory 50 for storing the receiver 30, a standard channel information table including ensemble channel information according to position information and frequency information, and an algorithm and an operating program as shown in FIGS. Accesses the stored program memory 60 and the two memories 50 and 60, and receives and parses the high frequency tuner and the OFDM channel decoder. When the stream and the ensemble channel information of the broadcast signal is taken to determine whether it is normal channel information. As a result of the check, the ensemble channel information of the corresponding frequency band is stored in the nonvolatile memory 50, and when abnormal channel information. A / V decoder 40 which checks the current position information from the position information signal received by the position information receiver and takes the ensemble channel information from the standard channel information table and stores it as channel information, and audio for audio and video output. Codec 70 and video encoder 80.

3 is an operation flowchart illustrating a channel search reception sensitivity improvement algorithm of a digital multimedia broadcasting (DMB) receiver according to an embodiment of the present invention. When (a1) full channel search is selected, a full channel scan is performed. A first step (S300 to S303) of checking whether an effective broadcast signal is searched for in a frequency band for the second step; S307) and (a3) classifying the case where the parsed ensemble channel information is normal and abnormal, respectively, and selecting the parsed ensemble channel information or the backed up ensemble channel information of the standard channel information table as channel information of the corresponding frequency band. It consists of a third step (S313) to store. Here, the standard channel information table is a set of channel information collected by frequency and region by collecting ensemble channel information from time to time, and stored in the nonvolatile memory 50 as shown in FIG. Ensure that information is preserved even when

The first step (a1) includes determining whether full channel search is selected (S203), and when the full channel search is selected, selecting a first frequency band for full channel scan in a high frequency tuner. Steps S300 and S301 and a step S303 of checking whether a valid broadcast signal is found in the selected frequency band.

The second step (a2) is performed when a valid broadcast signal is received as a result of the check of the first step, and has ensemble channel information parsed from a stream of the valid broadcast signal currently received by the OFDM channel decoder. In step S305, and determining whether the parsed ensemble channel information is present and normal (S307).

In step (a3), when the parsed ensemble channel information is normal, the parsed ensemble channel information is stored as channel information of a corresponding frequency band or the parsed ensemble channel information does not exist. If it is not the normal ensemble channel information, the step of checking the current position information using the information received from the outside (S309) and according to the current position information and frequency information from the standard channel information table previously stored in the memory Selectively performing step S311 of reading backed up ensemble channel information, and storing backed up ensemble channel information read from the standard channel information table as channel information of a corresponding frequency band (S315); Step (S315) and if the last frequency is not the next frequency is selected and valid again A step (S317) to return to step (S303) to determine the presence or absence of songsinho.

FIG. 4 is an operation flowchart illustrating a process of retrieving ensemble channel information backed up from a standard channel information table in the algorithm of FIG. 3, wherein step (a3) includes (a3-1) location information from the location information receiver. Receiving the data and recognizing the current location information (S401), (a3-2) retrieving the local standard channel information table corresponding to the location information from the memory by taking the current frequency information (S402); and (a3-3) retrieving the backed up ensemble channel information corresponding to the current position information and the currently selected frequency information from the searched standard channel information table (S403).

Referring to the operation flow of the method for improving the channel search reception sensitivity of the DMB receiver according to the embodiment of the present invention configured as described above, as shown in FIGS. 3 and 4, first, whether full channel search is selected (S202). Check it.

When the full channel search is selected, the first frequency for full channel scan is selected (S301) to confirm whether a valid broadcast signal is received in the selected frequency band (S300 to S303), and from the OFDM channel decoder The ensemble channel information parsed from the stream of the effective broadcast signal is taken to determine whether it is normal (S305 and S307).

In this case, the parsed ensemble channel information is divided into normal cases (YES branch of S307) and abnormal cases (NO branch of S307), and channel information is stored (S313). That is, when the parsed ensemble channel information is normal, the parsed ensemble channel information is stored as channel information of the corresponding frequency band (S313). On the contrary, when parsed ensemble channel information is not normal or not, the externally received location is stored. After confirming the current position information with the information signal (S309) and taking the ensemble channel information according to the current position information from the standard channel information table in which the channel information is divided according to the identified position information and frequency information (S311). The channel information of the band is stored (S313).

When the channel storage operation is completed, the next frequency set for the full channel search is selected (S317) and repeatedly performed for the above-described steps (S303 to S313), and this operation is set for the full channel search. Is repeated until the last frequency.

According to the DMB receiver to which the method for improving the channel search reception sensitivity according to the present invention is applied, for example, in the case of a general DMB receiver, after a full channel search in Seoul, the broadcast signal is weak on the way to Busan. When the full channel search is performed, the broadcast reception is weak, so even if there is a broadcast signal reception in the high frequency tuner, the OFDM channel decoder cannot fully decode the FIC information. However, when the algorithm according to the present invention is applied, the current position information is externally known. It is possible to import the ensemble channel information previously stored in the standard channel information table with the current position information and frequency value.

In the above, the present invention has been shown and described with respect to certain preferred embodiments. However, the present invention is not limited to the above-described embodiments, and those skilled in the art to which the present invention pertains can variously change variously without departing from the technical spirit of the present invention described in the following claims. You can do it.

According to the present invention, because of the characteristics of the DMB receiver can not always receive the broadcast signal in a good environment when the channel search in the presence of a weak electric field or interference signal when the broadcast signal is detected within a predetermined time, but not receive complete channel information Even if the actual broadcast is received, but the channel information cannot be obtained without error when searching for channels, even if the actual channel information cannot be obtained, the channel information is obtained by using the frequency information and the current position information from the previously collected standard channel information table. As a result, even if a weak signal is received, channel search is possible.

Claims (2)

delete A method for improving full channel search reception sensitivity in a DMB receiver having a high frequency tuner, an OFDM channel decoder, and a location information receiver, (a1) determining whether a full channel search is selected to determine whether a valid broadcast signal is received in a frequency band selected for a full channel scan in a high frequency tuner of the DMB receiver; (a2) As a result of the checking of the first step, when the valid broadcast signal is received, the ensemble channel information is parsed from the stream of the valid broadcast signal currently received from the OFDM channel decoder to determine whether the ensemble channel information is present or not and whether it is normal or abnormal. Determining a second step; (a3) If the parsed ensemble channel information is normal as a result of the determination of the second step, the parsed ensemble channel information is stored as channel information of a corresponding frequency band, and the parsed ensemble channel information does not exist or is normal ensemble channel. If not the information, and comprises a third step of reading the ensemble channel information backed up in accordance with the current position information and frequency information from the standard channel information table previously stored in the memory and stored as channel information of the frequency band, Step (a3) may include: (a3-1) receiving location information data from the location information receiver to recognize current location information; (a3-2) retrieving from the memory a standard channel information table of a region corresponding to the recognized current location information; (a3-3) Channel search reception sensitivity of the DMB receiver, comprising: searching for backed up ensemble channel information corresponding to current position information and currently selected frequency information from the searched standard channel information table; How to improve.

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