KR20070061294A - Tii decoder and deconding method - Google Patents

Abstract

A TII(Transmitter Identification Information) decoder and a decoding method are provided to stably detect TII(Transmitter Identification Information) included in a null period of a transmission frame and automatically control an identification threshold level of a signal magnitude of a reception symbol, required to discriminate an effective TII signal pattern from noise in a demodulated symbol to maintain an optimized operating state all the time. A TII decoder includes a magnitude acquisition unit(310), a phase acquisition unit(320), a TII pulse judgment unit(330), and a consistency checking unit(340). The magnitude acquisition unit monitors the magnitude of an input signal. The phase acquisition unit monitors the phase of the input signal. The TII pulse judgment unit determines input of TII pulses from the magnitude signal and the phase signal respectively obtained by the magnitude acquisition unit and the phase acquisition unit. The consistency checking unit checks whether a plurality of TII pulses has the same time delay and/or whether a TII pattern composed of the plurality of TII pulses is repeated.

Description

TI decoder and decoding method {TII Decoder and Deconding Method}

1 is a time slot diagram illustrating the presence of a TII signal in mode 1 according to the EUREAK147 standard.

2 is a table depicting a TII pattern of mode 1 in accordance with the EUREAK147 standard.

3 is a block diagram illustrating a configuration and a connection structure of a TII decoder according to an embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

300: TII decoder 310: magnitude acquisition unit

320: phase acquisition unit 330: TII pulse determination unit

340: consistency check unit 350: TII pattern output unit

360: automatic threshold control unit 370: lost counter

The present invention relates to a TII decoder for recognizing a TII pattern. In particular, the present invention relates to decoding a transmitter identification information (TII) in a receiver of a transmission / reception system using the EUREKA147 standard including Terrestrial-DMB (Digital Multimedia Broadcasting). The present invention relates to a decoder and a decoding method.

In other words, it is possible to stably detect TII information by using the repeatability of the TII signal pattern included in the null section of the transmission frame and the consistency of the repeated pattern, and also to detect the detection level ( The present invention relates to a decoding algorithm capable of low power implementation by automatically adjusting the threshold level so that the optimal level is always obtained so that the signal can be detected more stably than the conventional technology and the hardware size is small.

The TII signal is a signal transmitted every two frames in a null section in a transmission system that conforms to EUREAK147. The TII signal is used together with fast information channel (FIC) information to transmit or receive information on a transmitter or repeater that is currently receiving a signal. It serves as a reminder.

The TII information is composed of two values, MainID (p value in Equation 2) and subID (C value in Equation 2). As shown in FIG. 2, the main ID has 70 patterns of 0 to 69, and the subID has 24 values in the range of 0 to 23 as a delay time value. Since the value of SubID = 0 is reserved for satellite reception, in case of T-DMB, MainID and SubID may be combined to have a TII value of 70 * 23 = 1610.

Equations defining the TII signal are as shown in Equation 1 below, and the TII pattern according to each mode from Mode 1 to Mode 4 is as shown in Equations 2 to 5 below. The TII pattern in Mode 1 is determined by Equations 1 and 2, and its meaning is as shown in FIG.

PRS symbol: Phase Reference Symbol

FIG. 1 (A) shows 1536 data symbols after removing the guard band in transmission mode 1 in the TDMB or Eureka-147 standard, and the numbers indicate the frequency index in each symbol. Fig. 1B is an enlarged view of 1/4 of Fig. 1A. FIG. 1 (C) shows an ideal TII pattern value for the case of p = 18, c = 3, i.e., ab (p) = 01001110, according to FIG. 1 (B).

Ab (p) is determined by the 8-bit pattern defined in the Eureka-147 standard according to the MainID, that is, the p-value, and the 8-bit pattern of the ab (p) value is 48 bits in FIG. For each of eight blocks having a data symbol length, it is determined whether or not there is a bit pattern. SubID, i.e., the value of c, determines the position of the bit pattern, i.e., the shift amount, within a block of 48 data symbols as shown in FIG. The shift amount is determined by 2 * c, and the bit pattern is always present in even and odd pairs according to the equation when considering k = 1 to 768 and -768 to -1.

A conventional TII decoding method is as follows.

Since the TII signal is transmitted by being carried in the null symbol of every second transmission frame, a predetermined threshold is measured by measuring the power of the transmitted null symbol to first determine whether the TII signal is included in the current transmission frame. When the above value was measured, a method of determining that the TII signal was included was used. In this case, a method of accumulating several null symbols is used when measuring power. In addition, it should be considered that the threshold value is appropriately set according to the reception environment.

Once it is determined that the TII signal is present, the data of the received and demodulated null symbol is transferred to a processor such as a DSP and then used to correlate the received data with respect to each known TII pattern. I'm using the method. This method is difficult to use in a receiver without a DSP because it is difficult to use a DSP only for TII detection when the receiver does not include a DSP.

An object of the present invention devised to achieve the above object is to stably detect TII information included in a null section of a transmission frame.

Another object of the present invention is to automatically adjust a threshold level of a signal magnitude value of a received symbol necessary for distinguishing a valid TII signal pattern and noise in a demodulated symbol, thereby always operating optimally. To maintain state.

Another object of the present invention is to enable a fast and stable search for a TII signal pattern from null symbol data.

Another object of the present invention is to reduce the sensitivity to changes in the reception environment in detecting the TII pattern.

Another object of the present invention is to detect a TII pattern without any problem without knowing which frame the TII pattern transmitted in a null symbol is transmitted once every two frames.

Another object of the present invention is to simplify the structure of hardware required for detecting TII information.

Another object of the present invention is to enable real-time execution of TII information detection.

A TII decoder of the present invention for achieving the above object, the magnitude (magnitude) acquisition unit for monitoring the magnitude (magnitude) of the input signal; A phase acquisition unit for monitoring a phase of an input signal; A TII pulse determination unit for determining an input of a TII pulse from the magnitude signal and the phase signal; And a consistency check unit for checking whether the time delays of the plurality of TII pulses are the same and / or repeating the TII pattern including the plurality of TII pulses.

The TII decoding method of the present invention for achieving the above object comprises the steps of: monitoring the magnitude (magnitude) and phase of the input signal; If the magnitude of the input signal is greater than a predetermined peak threshold, determining the peak; Comparing the phases of two consecutive peaks of the peaks, and determining that TII unit pulses are generated when the phases are the same; Checking whether the time delays of the plurality of TII pulses are the same; Checking whether the TII pattern consisting of the plurality of TII pulses is repeated a predetermined number of times; And outputting the identified TII pattern.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the embodiments of the present invention illustrated in the following may be modified in many different forms, and the embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. .

(Example)

The configuration of the TII decoder according to an embodiment of the present invention is as shown in the block diagram of FIG. 3. The illustrated TII decoder 300 includes: a magnitude obtaining unit 310 for monitoring a magnitude of an input signal output from the Fourier transformer 200; A phase obtaining unit 320 for monitoring a phase of an input signal; A TII pulse determination unit 330 for considering an input signal larger than a predetermined threshold as a peak and determining a TII pulse when a peak of the same phase is repeated twice; And a consistency checker 340 for checking whether the time delays of the plurality of TII pulses are the same and / or whether the TII pattern including the plurality of TII pulses is repeated.

In order to provide a more improved function, the TII decoder 300 of the drawing gives the threshold value, and increases the threshold value when the count number of the TII pulse is less than the reference number, and the count number of the TII pulse is increased. In case of more than the reference number, the controller further includes an automatic threshold controller 360 for lowering the threshold value, or buffers the TII pattern output from the consistency checker 340. The apparatus may further include a TII pattern output unit 350 for maintaining a value, or may further include a lost counter 370 for counting the number of detection failures of the TII pattern.

Hereinafter, the operation of each block constituting the illustrated TII decoder will be described. First, the magnitude obtainer 310 and the phase acquirer 320 will be described. According to Equation 1 and Equation 2, the TII pattern is always represented as two pairs as shown in FIG. 1, but if k = i has a value of the TII pattern, k = i + 1 is required. Will exist and these two consecutive symbols will have the same phase. To have the same phase. This means that the values of the real part and the imaginary part have the same sign. Using this point, simple magnitude operations and phase information can be used to determine where the TII pattern is in the received null symbol. That is, the magnitude obtaining unit and the phase obtaining unit extract magnitude information and phase information from the input signal. However, in order to ensure stable TII reception rate, it is necessary to increase the reliability through multiple detections in order to increase the reliability of the decoded TII information. In this embodiment, the reliability of the detected value is checked by checking the consistency of the TII pattern. Will increase.

Next, the TII pulse determination unit 330 will be described. The illustrated TII pulse determiner 330 is implemented as a peak detector / decimator. The peak detection / decimator uses information extracted from the magnitude obtaining unit 310 and the phase obtaining unit 320 to have two consecutive values having the same phase code information, and the two consecutive values have peak thresholds. If it is larger than the value pkThres, it is recognized as a peak value, and the position signal corresponding to the peak value of the TII pattern is recognized as having the largest value among the peaks in the 48-time slot symbol data block. Here, the data block performs decimation for converting two data received as an input into one position signal, and outputs the decimated signal to the consistency checker 340.

Next, the consistency check unit 340 and the consistency check process performed herein will be described. According to Equations 1 and 2, the pattern of FIG. 1 (B) is repeated four times in FIG. That is, the 8-bit pattern of ab (p) is repeated four times and its value must be the same. In addition, when the TII pattern is present in each of the 48 timeslot symbol data blocks in FIG. 1 (B), all have the same shift amount, that is, the same sub ID (c value). Repeat 32/2 = 16 times and all must be the same value.

The peak detection / decimator block determines whether a TII pattern is present in the 48 timeslot symbol data block of FIG. 1 (C), and the position in the 48 timeslot symbol data block is set to c value for the existing block. Record and check for consistency with the previous c value and also record the ab (p) bit pattern as '1'. In addition, it records that the ab (p) bit pattern is '0' for the 48 symbol data blocks in which the TII pattern does not exist. Accordingly, the process may check whether the time delays of the plurality of TII pulses are the same (first consistency check). In addition, when the foregoing operation is completed for the eight 48 symbol data blocks, the 8-bit pattern of the recorded ab (p) is compared with the 8-bit pattern of the previous ab (p) and checked for consistency. Accordingly, it is possible to check whether or not the TII pattern including the plurality of TII pulses is repeated the number of times according to the standard (second consistency check).

By continuously checking whether the c value and the ab (p) pattern are kept constant throughout the section (A) of FIG. 1, the reliability of the c value and the ab (p) pattern value can be increased, thereby providing stable TII decoding. This becomes possible. Both the first and second consistency checks are preferably performed for more accurate TII decoding, but may be implemented to perform only one of the two checks for extreme structure simplifying purposes. Meanwhile, the consistency checker 340 may include an 8-bit register for the second consistency check.

Next, the automatic threshold controller 360 will be described. In order to more clearly understand the operation of the automatic threshold controller 360, reference should be made to FIGS. 1 and 3.

The automatic threshold controller 360 outputs a peak threshold value (pkThres) used to determine a valid peak in the peak detection / decimator block 330, and then turns on a predetermined initial threshold at the beginning of driving. The value is output as the peak threshold value (pkThres). After the initial state, the peak threshold value pkThres is automatically adjusted to an optimal value by using a peak counting value and a TII detection success signal.

In the case of successfully demodulating the TII pattern normally, the TII detection success signal is enabled and the peak counting value should be 16 in mode 1. FIG. This means that 16 peaks must occur if the detection is successful.

If the TII pattern is not found normally, the peak counting value will be greater than or less than 16. If the peak counting value is less than 16, the peaks of some of the actual TII patterns will peak. Since the situation is smaller than the threshold value pkThres and not detected, it is determined that the peak threshold value pkThres is set slightly higher, thereby reducing the peak threshold value pkThres. If the Peak Counting value is greater than 16, the peak threshold due to noise, as well as the actual TII pattern, is larger than the peak threshold value (pkThres). It is determined that pkThres is set to be somewhat low, thereby increasing the peak threshold value pkThres.

By setting the increase and decrease values of the peak threshold value (pkThres) differently, it is possible to control between fine detection and fast detection.If the increase value is set higher than the decrease value, the time required for successful detection after one failure of TII detection is determined. It is longer, but the trend of setting the peak threshold value (pkThres) can be predicted, the direction of decreasing the peak threshold value (pkThres) is finely adjusted, and the default peak threshold value (pkThres) is rather high. It is preferable at the point etc. which are advantageous. As described above, the TII detection apparatus according to the present embodiment may autonomously maintain / adjust the optimal peak threshold value pkThres without external adjustment.

Next, the operation of the lost counter 370 will be described. The illustrated lost counter 370 records the number of times the detection of the TII pattern has failed when the TII pattern has not been successfully demodulated. When the number of failures exceeds the set LostTimeOut value, the lost counter 370 shows an UnLocked signal. Output and change the TII pattern output to a value that indicates a predetermined Undetected state.

Since the TII pattern is received in a null symbol at the actual receiving end, the reception rate is weak because it is not a device for data protection compared to other general data symbols. However, since the TII pattern will not change frequently due to the nature of the TII information, it may be advantageous to assume that the TII pattern can be continuously communicated with a transmitter that was previously communicating when the TII pattern has not been received for a predetermined short period (free period). . The lost counter 370 is to measure the margin period, thereby improving the robustness of the TII pattern.

Finally, the illustrated TII pattern output unit 350 will be described. If the TII pattern is successfully detected, it is immediately changed to a new value. If the detection of the TII pattern fails, the previous TII pattern value is maintained until the reset signal is received from the lost counter 370. When a reset signal occurs, it changes to a value that means Undetected. The undetected display value is a value other than MainID and SubID defined by the standard.

The combination of the lost counter 370 and the TII pattern output unit 350 may simultaneously improve the fast detection of the TII pattern and the robustness of the detected TII pattern. On the other hand, the present invention processes on-the-fly using symbol data output one by one from the FFT block 200 without using a memory device, so the order of the detected ab (p) patterns is actually shown in FIG. 2. Ab (p) pattern and the order may be different, the TII pattern output unit also plays a role in rearranging the order.

The TII detection method performed in the TII decoder 300 according to the present embodiment includes: monitoring magnitude and phase of an input signal (a); If the magnitude of the input signal is larger than a predetermined peak threshold, determining the peak (b); (C) comparing the phases of two consecutive peaks of the peaks, and determining that the phases are identical to generate TII unit pulses; Checking whether the time delays of the plurality of TII pulses are the same; (E) checking whether the TII pattern consisting of the plurality of TII pulses is repeated a predetermined number of times; And (f) outputting the identified TII pattern.

Referring to FIG. 3, the TII detection method is performed in the magnitude obtaining unit 310 and the phase obtaining unit 320, and the steps (b) and (c) are performed. Is performed by the TII pulse determination unit 330, and steps (d) and (f) are performed by the consistency checker 340.

The TII detection method is performed on 1536 data symbols in the TDMB or Eureka-147 standard, and reducing the peak threshold when the number of peaks determined for the 1536 data symbols is less than 16. Wow; If the number of peaks determined to be greater than 16 may further include increasing the peak threshold, and the added steps may be performed by the automatic threshold controller 360 of FIG. 3.

In the step (e), if any of the 1536 data symbols is determined as the peak in the 48-time slot symbol data block, the bit pattern is determined as '1'. 0 'to confirm the TII pattern.

The description so far has been described in detail mainly in the case of Equation 1, Equation 2, and Mode 1 of FIG. In this case, only the length of the transmission frame and the null symbol is 1/2 the length of Mode 1 in Mode 4, the 1/4 length of Mode 1 in Mode 2, and the 1/8 length of Mode 1 in Mode 3 . Accordingly, although the length of FIG. 1A, that is, the length of the null symbol may be different and the number of times the TII pattern is repeated, the basic concept of the algorithm of the present invention may be equally applied. Since the description can be easily inferred, the detailed description will be omitted.

The present invention has been described in detail with reference to preferred embodiments, but the present invention is not limited to the above embodiments, and various modifications can be made by those skilled in the art within the scope of the technical idea of the present invention. Do.

By implementing the TII decoder according to the present invention, it is possible to stably detect the TII information by using the repeatability of the TII signal pattern included in the null section of the transmission frame and the consistency of the repeated pattern.

In addition, the TII decoder of the present invention automatically adjusts a threshold level of a signal magnitude value of a received symbol necessary for distinguishing a valid TII signal pattern and noise in a demodulated symbol to always maintain an optimal value. There is also an effect.

In addition, the TII decoder of the present invention has an effect of allowing a fast and stable search for a TII signal pattern from one null symbol data.

In addition, the TII decoder of the present invention maintains the previous TII pattern value for a certain time even if the detection of the TII signal fails, thereby reducing the sensitivity to changes in the reception environment in detecting the TII pattern.

In addition, the present invention has the effect of ensuring the detection of a desired TII pattern without knowing which frame the TII pattern transmitted in a null symbol is transmitted once every two frames.

In addition, the algorithm of the present invention can improve the speed of the most possible configuration by hardware logic, the effect that can detect the TII pattern in real time (Real Time) without the need to store the received symbol, or eliminate the need for a memory device and the existing DSP scheme It also has the effect of having a very small hardware size.

Claims (10)

A magnitude obtainer configured to monitor a magnitude of the input signal; A phase acquisition unit for monitoring a phase of an input signal; A TII pulse determination unit for determining an input of a TII pulse from the magnitude signal and the phase signal; And Consistency check unit for checking at least one of whether the time delays of the plurality of TII pulses are the same and whether the TII pattern including the plurality of TII pulses is repeated. TII decoder comprising a. The method of claim 1, wherein the TII pulse determination unit, A TII decoder characterized in that an input signal larger than a predetermined threshold is regarded as a peak and judged as a TII pulse when a peak of the same phase is repeated twice. The method of claim 2, wherein the consistency check unit, And counting the number of occurrences of the TII pulse during a predetermined time period. The method of claim 3, Giving the threshold, When the count number of the TII pulse is less than the reference number, the threshold is increased. Automatic threshold control unit for lowering the threshold value when the number of counts of the TII pulse is greater than the reference number TII decoder further comprising. The method of claim 1, Buffering the TII pattern output from the consistency checker, TII pattern output unit for maintaining previous buffering value when TII pattern detection fails TII decoder further comprising. The method of claim 1, Lost counter to count the number of failed detections of TII patterns TII decoder further comprising. (a) monitoring the magnitude and phase of the input signal; (b) if the magnitude of the input signal is greater than a predetermined peak threshold, determining the peak; (c) comparing the phases of two consecutive peaks of the peaks, and determining that TII unit pulses are generated when the phases are the same; (d) checking whether the time delays of the plurality of TII pulses are the same; (e) checking whether the TII pattern consisting of the plurality of TII pulses is repeated a predetermined number of times; And (f) outputting the identified TII pattern TII detection method which consists of. The method of claim 7, wherein Steps (a) to (f) are performed on 1536 data symbols in the TDMB or Eureka-147 standard. The method of claim 8, wherein for the 1536 data symbols, Reducing the peak threshold value if the number of peaks determined to be less than 16; And If the number of peaks determined to be greater than 16, increasing the peak threshold value. TII detection method further comprising. The method of claim 8, In the step (e), If one of the 1536 data symbols is determined as the peak in the 48-time slot symbol data block, the bit pattern is determined as '1', And if it is determined that there is no peak, the bit pattern is identified as '0'.

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