KR101295573B1 - Pulse Shaping Filter Module, Method For Adjusting Transmission Time Using The Same, And Method and Apparatus For Detecting Receiving Timing - Google Patents

Abstract

The present invention relates to a pulse shaping filter module, a transmission timing adjusting method using the same, and a receiving timing detecting method and apparatus. According to the present invention, by changing the filter shaping coefficient value according to the timing offset value for adjusting the prime multiple timing of the timing adjustment unit, it is possible to effect such that the timing of the transmission signal is substantially adjusted.

Timing adjustment, pulse shaping filter

Description

Pulse Shaping Filter Module, Method For Adjusting Transmission Time Using The Same, And Method and Apparatus For Detecting Receiving Timing}

1 illustrates a conventional transmission stage structure including a timing controller.

2 illustrates a transmission stage structure designed to allow a timing controller to control a pulse shaping filter in accordance with one embodiment of the present invention.

3 is a diagram showing values of pulse shaping filter coefficients at sampling time points for sample timing offsets according to an embodiment of the present invention.

4 illustrates a pulse shaping filter module of a transmitting end according to an embodiment of the present invention.

Fig. 5 is a diagram showing the structure of a reception timing detection device of a receiving end according to an embodiment of the present invention.

The present invention relates to wireless communication technology, and more particularly, to a pulse shaping filter module, a transmission timing adjusting method using the same, and a receiving timing detecting method and apparatus.

In general, AD / DA in a mobile terminal has the same sample rate, and they also have a rate of 4 to 8 times the chip (or symbol) speed. Most mobile terminals perform sampling at a rate four times the symbol rate at the receiving end. This trend is even more pronounced in TDD (Time Division Duplexing) systems because Tx and Rx operate at the same timing.

The TD-SCDMA system, which is one of the TDD-based CDMA systems, has a closed loop synchronization control function for accurate uplink synchronization adjustment. In this case, the basic unit of the closed loop synchronization adjustment is k / 8 (k is a value of 1 to 8). And informs individual terminals in the network) chip. If the oversample rate of the terminal is 4, the synchronization adjustment unit that the terminal can adjust itself is 1/4 symbol (chip in CDMA). Therefore, in the case of TD-SCDMA, if the synchronization adjustment unit of the network is 1/8 (k = 1) chip, the terminal may not satisfy this and performance may be degraded.

1 is a diagram illustrating a conventional transmission stage structure including a timing controller.

The conventional transmission stage as shown in FIG. 1 passes through a modulator 101, is oversampled in the oversampling stage 102, and then is sampled in the timing adjusting unit 103 under the control of the timing controller 104. After passing through the pulse shaping filter 105, it is output through an antenna by a transmitter 107 via a DAC (digital-analog converter) 106.

In the conventional transmission stage, the timing controller 104 adjusts the timing adjustment unit according to the sample rate, that is, an integral multiple of 1 / sample rate. In this case, the timing is adjusted by changing the starting position of the data in the transmission sample sequence. Do it.

However, in the conventional transmission stage, timing adjustment in a unit smaller than the timing adjustment unit according to the sample rate as described above is impossible. Accordingly, there is a problem that the conventional transmission end cannot accurately perform the timing adjustment required by the base station.

For example, in the case of TD-SCDMA, the chip rate is 1.28Mcps and the sample rate of a typical terminal is 5.12Msps. However, in general, the base station uses 10.24Msps, and if the base station requests timing adjustment of 1/8 chip unit with k = 1 as the basic unit of the closed loop synchronization adjustment, the terminal does not satisfy this requirement. This limitation eventually results in increased multiple access interference on the uplink, resulting in poor link performance and system capacity.

SUMMARY OF THE INVENTION An object of the present invention for solving the above-described problems is to apply a change in digital signal to an analog signal by applying a change in the analog signal to the digital signal and to adjust the transmission timing irrespective of the sample rate limit of the DAC. To provide a pulse shaping filter module.

In addition, when timing is adjusted as described above, it is an object of the present invention to provide a timing detection method and apparatus for acquiring an accurate timing signal at a receiving end.

A timing adjustment method according to an embodiment of the present invention for achieving the above object comprises the steps of: inputting a fractional sample timing adjustment signal of a timing adjustment unit according to a sample rate into a pulse shaping filter; And adjusting a filter coefficient of the pulse shaping filter according to the fractional sample timing adjustment signal.

In this case, the fractional sample timing adjustment signal includes timing offset information, and in adjusting the coefficients of the pulse shaping filter, the pulse shaping filter selects different filter coefficients according to the timing offset information and filters them differently. It can be adjusted to perform.

On the other hand, the pulse shaping filter module according to another embodiment of the present invention includes a plurality of pulse shaping filters corresponding to each of a plurality of timing offset information, wherein the plurality of pulse shaping filters each includes a small number of timing adjustment units according to a sample rate. It is characterized in that it is selected according to the double sample timing adjustment signal.

In this case, the fractional sample timing adjustment signal may include timing offset information, and the plurality of pulse shaping filters may have different filter coefficients according to the timing offset information.

In addition, the reception timing detection method according to another embodiment of the present invention includes the steps of outputting the output signal through a plurality of pulse shaping filter corresponding to each of the plurality of timing offset information; And acquiring timing information using the plurality of output signals.

In this case, the timing information acquisition may use any one of a timing synchronization estimation method and a maximum energy selection method.

Finally, a reception timing detection apparatus according to another embodiment of the present invention, a pulse shaping filter module including a plurality of pulse shaping filters corresponding to each of the plurality of timing offset information; And a timing information acquisition module that acquires timing information by using the plurality of output signals output by the pulse shaping filter module.

In this case, the timing information acquisition module may be any one of a maximum energy signal sequence selector and a timing synchronization estimator.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description, together with the accompanying drawings, is intended to illustrate exemplary embodiments of the invention and is not intended to represent the only embodiments in which the invention may be practiced.

The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, those skilled in the art will appreciate that the present invention may be practiced without these specific details. In some instances, well-known structures and devices are omitted or shown in block diagram form around the core functions of each structure and device in order to avoid obscuring the concepts of the present invention. In the following description, the same components are denoted by the same reference numerals throughout the specification.

2 is a diagram illustrating a transmission stage structure designed to allow a timing controller to control a pulse shaping filter according to an embodiment of the present invention.

The transmission stage structure according to the embodiment of the present invention shown in FIG. 2 is the same in basic construction as the conventional transmission stage structure shown in FIG. However, the timing controller 104 ′ may adjust not only the integer times but also the decimal times of the timing adjustment unit according to the sample rate. In this case, the timing adjustment signal below the decimal point among the timing adjustment signals may be pulsed instead of the timing adjustment unit 103. It differs in the point input into the shaping | molding filter 105 '. In addition, the pulse shaping filter 105 ′ according to the embodiment of the present invention shown in FIG. 2 changes the pulse shaping filter coefficient according to the sample timing offset included in the timing adjustment signal received below the decimal point, thereby changing the output shaping filter. The same effect as the timing adjustment of the decimal multiple of the timing adjustment unit according to the sample rate can be performed.

As described above, a method of changing the coefficient value of the pulse shaping filter according to the sample timing offset will be described in detail.

3 is a diagram illustrating values of pulse shaping filter coefficients at sampling time points for sample timing offsets according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a proposed method for applying a 5.12Msps sample rate four times the chip rate to an RRC filter used in 3GPP. The signal located at the center of the three signal waveforms shown in FIG. 3 illustrates a case where the timing offset below the decimal point is 0, while the waveform shown on the upper part illustrates the case where the timing offset below the decimal point is 0.5, at the bottom. Shows the case where the timing offset below the decimal point is -0.5. The structure that can adjust the timing offset below the decimal point is a structure for receiving the synchronization control of the base station of 10.24Msps in the terminal operating at 5.12 Msps.

As shown in FIG. 3, a time difference of 0.5 samples in terms of an analog signal is represented by a difference in tap coefficients of an RRC filter at a sample time point. In FIG. 3, the dotted line is the point at which the actual sampling is performed, and it can be seen that the value of the RRC filter is different depending on the timing offset value below the decimal point as described above at the sampling point. As a result, when the tap coefficient of the RRC filter is configured differently from the case where the timing is 0 to adjust the timing below the decimal point, the effect is as if the actual time is adjusted.

4 is a diagram illustrating a pulse shaping filter module of a transmitting end according to an embodiment of the present invention.

Specifically, FIG. 4 includes N pulse shaping filters 401-1 through 401-N in accordance with coefficient values corresponding to timing offsets in intervals of N equal intervals for timing offsets below the decimal point. In this case, the sample timing offset below each decimal point corresponds to the case of 0, 1 / N, 2 / N, ..., (N-1) / N samples.

In addition, in the case of setting N = 2, it can be set in units of timing offset of 0.5 samples below the decimal point as shown in FIG. 3, and 0.5 samples as shown in FIG. 3 including a separate pulse shaping filter for offset in the '-' direction. You can also set the offset of.

In FIG. 4, when the pulse shaping filter module 401 receives a timing adjustment value of less than a decimal point from the timing controller 402, a filter corresponding to the timing among the plurality of filters 401-1 to 401-N is selected and filtered. This is performed, thereby enabling timing adjustment below the decimal point by selecting the filter coefficient as shown in FIG.

4 illustrates a hardware implementation in which N pulse shaping filters 401-1 through 401 -N are switched according to timing offset information below a decimal point, and are selected as an example. It is only for illustrating a concept according to an exemplary embodiment, and selecting different pulse shaping filter coefficients according to timing offset information may be implemented in hardware or software.

On the other hand, the following is another embodiment of the present invention to obtain a more accurate timing information by applying a method for adjusting the timing corresponding to a decimal multiple of the timing adjustment unit according to an embodiment of the present invention as described above to the receiving end It describes a method according to.

5 is a diagram illustrating a structure of a reception timing detection apparatus of a reception terminal according to an embodiment of the present invention.

According to an embodiment of the present invention, an error due to timing is also received at the receiving end using the pulse shaping filter module 503 including the filters 503-1 to 503-N according to N pulse shaping filter coefficients as shown in FIG. Can be reduced.

That is, the received signal passes through the ADC (analog-to-digital converter) 502 and passes through all N pulse shaping filters 503-1 to 503-N, and the maximum energy detection method among the N signals output or The timing information acquisition module 504 including the timing synchronization estimator may be used to find the most optimal timing offset and use the corresponding pulse shaping filter output. In general, the timing information at the receiving end is dependent on the timing adjustment value at the transmitting end, etc., rather than the variation caused by the channel through which the signal is transmitted, and the timing at which the timing is adjusted through the transmitting end having the configuration as shown in FIG. In order to precisely acquire timing, timing information up to a fraction of a timing adjustment unit may be obtained through a structure including a plurality of pulse shaping filters as shown in FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The foregoing description of the preferred embodiments of the present invention has been presented for those skilled in the art to make and use the invention. Although the above has been described with reference to the preferred embodiments of the present invention, those skilled in the art will variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. I can understand that you can. Accordingly, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

According to one embodiment of the present invention as described above, the change in digital timing is applied to the analog signal by applying the change to the digital signal inversely, so that the transmission timing can be adjusted regardless of the sample rate limit of the DAC. It is easy to implement through the filter module.

In addition, when timing is adjusted in this way, accurate timing detection is possible through a module including a plurality of pulse shaping filters in order to obtain an accurate timing signal at a receiving end.

Claims (8)

Inputting a fractional sample timing adjustment signal of a timing adjustment unit according to a sample rate into a pulse shaping filter; And And adjusting the filter coefficients of the pulse shaping filter in accordance with the fractional sample timing adjustment signal. The method of claim 1, The fractional sample timing adjustment signal includes timing offset information, In the step of adjusting the coefficient of the pulse shaping filter, the pulse shaping filter is adjusted to perform different filtering by selecting different filter coefficients according to the timing offset information. A plurality of pulse shaping filters corresponding to each of the plurality of timing offset information, And wherein the plurality of pulse shaping filters are selected in accordance with a fractional sample timing adjustment signal of a timing adjustment unit according to a sample rate. The method of claim 3, wherein The fractional sample timing adjustment signal includes timing offset information, The plurality of pulse shaping filters have different filter coefficients according to the timing offset information. Outputting the received signal as a plurality of output signals passed through a plurality of pulse shaping filters corresponding to each of the plurality of timing offset information; And And receiving timing information using the plurality of output signals. 6. The method of claim 5, The timing information acquisition method uses any one of a timing synchronization estimation method and a maximum energy selection method. A pulse shaping filter module including a plurality of pulse shaping filters corresponding to each of the plurality of timing offset information; And And a timing information acquiring module for acquiring timing information using a plurality of output signals output by the pulse shaping filter module. The method of claim 7, wherein And the timing information acquiring module is one of a maximum energy signal sequence selector and a timing synchronization estimator.

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