KR20010047120A - Synchronous Signal Receiving Unit for WLL - Google Patents

Abstract

PURPOSE: An apparatus for receiving a synchronizing signal of WLL(Wireless Local Loop) is provided to detect a synchronizing signal in many times and which a location difference of each synchronizing signal to output one of the synchronizing signal with the minimum location difference and the maximum signal level by detecting a synchronizing signal being accurate and whose signal level is enough in a noise rich environment. CONSTITUTION: A plurality of register(10) receives sequentially a synchronizing signal of a pilot channel to output and shift the same. A tap coefficient generator(50) generates and inputs in order a plurality of the tap coefficients during the frame interval of the pilot channel. A plurality of multipliers(20) connected to each of the plurality of a register(10) receives the synchronizing signal and multiplies the synchronizing signal with the plurality of the tap coefficients received from the tap coefficient generator(50) to output the result. An adder(40) sums and outputs the signals received from the plurality of the multipliers(20). A sorting section(60) detects a synchronizing signal in which a level is most large and a location is most suitable by sorting the signals outputted from the adder(40).

Description

Synchronous Signal Receiving Unit for WLL

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for receiving a synchronous signal received through a pilot channel of a CDMA wireless subscriber network (WLL), and in particular, to detect a synchronous signal many times during a frame period of a predetermined time unit. In addition, the present invention relates to a synchronization signal receiving apparatus which prevents inaccuracy and time delay of a synchronization signal caused by noise or the like by classifying and detecting a synchronization signal having a precise synchronization position among the synchronization signals detected many times.

The code division multiple access (CDMA) scheme transmits a synchronization signal in units of frames by using a pilot channel. On the receiving side, a code division multiple access (CDMA) scheme receives a synchronization signal of the pilot channel. Although the data signal is received in a periodic unit, when the synchronization signal is not received due to noise or the synchronization signal in which an error occurs, the data signal in the corresponding frame unit is not received. In wireless subscriber network (WLL), personal communication system (PCS), etc., which is used, receiving synchronization signals through the pilot channel is one of very important problems.

Hereinafter, an apparatus for receiving a synchronization signal of a wireless subscriber network according to the prior art will be described with reference to the accompanying drawings.

1 is a functional block diagram of a synchronization signal receiving apparatus of a wireless subscriber network according to an embodiment of the prior art.

Referring to the accompanying drawings, a synchronization signal receiver in a wireless subscriber network terminal according to the prior art is applied to the pilot signal output from the high-frequency receiver of the terminal not shown in the drawing is moved in the order of input ( Shift) and output multiple registers (10),

A fixed tap coefficient generator 70 for generating a fixed tap coefficient to detect synchronization of a pilot signal applied to the register 10;

A plurality of multipliers or multipliers 20 for multiplying the pilot signal applied from the register 10 and the fixed tap coefficient applied from the fixed tap coefficient generator 70;

The adder 40 adds all of the signals output from the plurality of multipliers 20.

Hereinafter, a wireless subscriber network synchronization signal receiving apparatus according to the related art having the above configuration will be described in detail with reference to the accompanying drawings.

In a wireless subscriber network (WLL) system, a base station (Site) transmits a pilot channel signal indicating the start of the transmitted data signal in wireless transmission of data signals corresponding to a plurality of terminals as high frequency signals. Done.

The subscriber station receiving the pilot signal from the base station detects a pilot channel signal through its own high frequency receiver and detects a synchronous signal. Matched) is applied to a sync signal receiving device which is a filter.

The matched filter, which is the synchronization signal receiving device, applies a plurality of registers 10 to temporarily store and shift the pilot channel signals in units of frames received from the receiving unit in order. ) Is composed of a number of registers that can accommodate all pilot signals received as bit signals in frame units that are wirelessly transmitted from the base station through a pilot channel.

The sync signal receiving device or matched filter may be configured such that the multipliers 20 having the same number as the plurality of registers 10 are configured in one-to-one (1: 1) and connected to each other. Each of the signals stored in the register 10 is applied.

The multiplier 20 is connected to the fixed tap coefficient generator 70 at the same time, and receives a fixed tap coefficient from the fixed tap coefficient generator 70.

The plurality of multipliers 20 receive pilot signal synchronization signals from the corresponding register 10 and simultaneously multiply and output tap coefficients applied from the fixed tap coefficient generator 70.

The signals output from the plurality of multipliers 20 are added by the adder 40 and then output a synchronization signal having an associated signal (Correlation) value.

In the case where the related signal value is a signal having no error higher than or equal to a certain level, the signal is used as a synchronous signal by a processor not shown in the drawing, and is determined in advance by a noise or the like. If a certain level value is not output or there is an error, the data of the frame cannot be received and a data error occurs.

That is, since the Tap Coefficient, in which the synchronous signal of the pilot channel is received in a predetermined form and is multiplied only once with the synchronous signal of the pilot channel, is also fixed, the tap coefficient and the multiplier ( If there is no error in the pilot signal multiplied by 20), the synchronization signal output from the multiplier 20 becomes the maximum value, and the maximum value is added by the adder 40. The maximum associated signal (Correlation) value is thus a synchronous signal.

However, such a conventional technique is received through the pilot channel by an electromagnetic noise signal generated by an electrical noise signal generated in a surrounding area or a strong signal using a similar frequency in an adjacent area. An error occurs in the sync signal.

The pilot signal having an error as described above is multiplied by a fixed tap coefficient, so that the maximum value is not output, and the correlation value added with the above value is a predetermined constant. By not exceeding the value of the level, a result is not detected as a synchronous signal. Therefore, the data signal of the corresponding frame is not detected, resulting in a data error.

According to the present invention, a variable tap coefficient generator for generating a plurality of variable tap coefficients during a predetermined frame period can be added to detect a plurality of synchronization signals at frame unit time, and at the same time, the plurality of detected synchronization signals can be classified and optimally related. It is an object of the present invention to provide an apparatus capable of extracting an accurate synchronization signal from a pilot channel signal even in a noisy environment by adding a sorting unit for extracting a signal value.

In order to achieve the above object, the present invention provides a plurality of registers that sequentially receive and output a synchronization signal of a pilot channel, and a tap that sequentially generates and outputs a plurality of variable tap coefficients during a predetermined frame period. A plurality of multipliers connected to the coefficient generator, the plurality of registers respectively to receive a synchronization signal, and multiplied by a plurality of tap coefficients respectively applied from the tap coefficient generator, and a signal received from the plurality of multipliers, respectively. And a sorting unit for classifying a signal output from the adder and extracting a synchronous signal having the highest level and the most optimal position by adding the summation and outputting the summation signal.

1 is a functional block diagram of a synchronization signal receiving apparatus of a wireless subscriber network according to an embodiment of the prior art;

2 is a functional block diagram of a synchronization signal receiving apparatus of a wireless subscriber network according to an embodiment of the present invention;

3 is a diagram illustrating tap coefficient generation periods that occur for each frame unit according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

10: register 20: multiplier

30 control unit 40 adder

50,70: tap coefficient generator 60: sorting part

Hereinafter, a synchronization signal receiving apparatus of a wireless subscriber network according to an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 2 is a functional block diagram of a synchronization signal receiving apparatus of a wireless subscriber network according to an embodiment of the present invention, and FIG. 3 is a diagram illustrating tap coefficient generation periods generated for each frame unit according to an embodiment of the present invention.

Referring to the accompanying drawings, the synchronization signal receiving apparatus according to the present invention outputs the pilot signal from the high frequency receiver of the wireless subscriber network not shown in the order in which the synchronization signal of the pilot channel is applied and at the same time the received pilot signal A plurality of registers 10 shifted to a stage,

A control unit 30 for generating a control signal for controlling the entire synchronization signal receiving apparatus;

When the transmitter generates a CDMA signal at each transmission time of a data transmission frame transmitted by the wireless subscriber network (WLL) in a CDMA manner, for example every M msec, according to the control signal of the controller 30, Using the same pseudo-random noise seed (PN-SEED) signal as the pseudo-random noise seed (PN-SEED) signal, the tap coefficient is given a predetermined constant during the frame period time. Variable tap coefficient generator 50 that occurs multiple times, in one embodiment, N times,

A plurality of multipliers 20 for multiplying each bit of the pilot signal applied from the register 10 with N times the tap coefficient applied from the tap coefficient generator 50, respectively,

An adder 40 for outputting a correlation value obtained by adding all the signals applied from the plurality of multipliers 20;

A sorting unit 60 receives a related signal value from the adder 40 and extracts a synchronization signal having an optimal position value and a best signal level value. It is composed.

Hereinafter, a wireless subscriber network (WLL) synchronization signal receiving apparatus having the above configuration will be described in detail with reference to the accompanying drawings.

The plurality of registers 10 are connected in series, and when the received signal of the pilot channel output from the high frequency receiver of the wireless subscriber network (WLL) terminal is applied, the plurality of registers 10 are continuously shifted and stored in order, and the stored signal is stored. Are respectively output to the corresponding multiplier 20.

It is assumed that a unit time occupied or required by a pilot signal in a frame unit, that is, a sync signal in a frame unit, transmitted from the CDMA type wireless subscriber network (WLL) base station through a pilot channel is 'M' msec. do.

The variable tap coefficient generator 50 may detect a synchronous signal for 'N' times during M msec, which is a unit time of the frame, by a control signal of the controller 30. ) Generates a tap coefficient signal and applies a variable tap coefficient value corresponding to each of the plurality of multipliers 20.

In addition, it is assumed that a time taken for one variable tap coefficient applied from the variable tap coefficient generator 50 to be applied to the plurality of multipliers 20 once is 'T'.

When a pilot signal, that is, a synchronous signal, transmitted from a base station (SLL) of the wireless subscriber network (WLL) is detected by the terminal, within a range of time units from a time when the terminal starts detecting the pilot signal. Should be detected, it is assumed that the time when the terminal starts detection and the time transmitted by the base station are the same time.

However, in actuality, a time difference between a detection start time, that is, a delay time or an arrangement time difference, occurs between the time when the terminal starts detecting and the time when the terminal detects the detection time, and the alignment time is set to 'L'. Assume that the following equation can be calculated.

0 〈L 〈(M / N-T)

However, T <M / N.

L; Alignment point

M; Unit time of frame

N; Number of occurrences of variable tap coefficient / number of synchronous signal detection

T; Time to complete tap factor loading / load completion time to register of received signal

That is, only when the above Equation 1 is satisfied, N sync signals can be detected during the frame unit time M msec of the pilot signal.

If the pilot signal received from the terminal receiver of the CDMA wireless subscriber network is delayed by an 'L' time from a synchronization time point for detecting the pilot signal, as shown in FIG. The pilot signal is applied to the plurality of registers 10 delayed by the 'L' time.

The synchronization time point can be checked simultaneously by the transmitter and the receiver of the base station and the terminal, and occurs in each frame unit.

The variable taps applied to the register 10 are first applied from the variable tap coefficient generator 50 to vary and apply coefficients N times during a unit frame period time of the pilot signal. The coefficients are multiplied by the multiplier 20, applied to the adder 40, and added to detect or output an associated Correlation value.

The pilot signal applied to the register 10 is again delayed or offset by M / N time from the variable tap coefficient generator 50 and then changed or changed to be applied to the second variable. The tap coefficients are multiplied by the multiplier 20 and applied to the adder 40 to be added to detect or output the correlation value again.

Again, the multiplier 20 is multiplied by a tap coefficient applied after a third change or variable from the variable tap coefficient generator 50 after being delayed or offset for 2M / N time, and adder. By adding at (40), the signal is detected or outputted again as a synchronous signal, or repeated N times, and the N sync signals, i.e., the correlation signal (Correlation) values are repeated. Detect or output.

N synchronous signals, which are N related signal values detected or output from the adder 40, are applied to the sorting unit 60.

The sorting unit 60 delays each measurement of 'L' values, which are alignment points of the pilot channels received from the control unit 30, and N variable coefficient values output from the variable tap coefficient generator 50. ) The position error value for each sync signal measured N times can be calculated by receiving the time or Off Set time information and the like and performing the comparison process.

At the same time, the sorting unit 60 classifies and detects a synchronous signal having the smallest level of the signal among the synchronous signals measured with the smallest position error value and N times, and corresponding offset or The delay time value is compensated and output to the processing unit not shown in the drawing.

In other words, during the frame period of the pilot channel, a 'N' sync signal is detected, and a sync signal having the highest signal strength and the smallest error value of the sync position is classified and used as a synchronous signal.

Therefore, not only the accurate synchronization signal can be detected from the synchronization signal of the pilot channel in which an error occurs due to external electromagnetic noise, but also the synchronization signal is not detected, thereby solving the problem of losing the data of the corresponding frame.

The apparatus for receiving a synchronization signal of the CDMA wireless subscriber network (WLL) of the present invention as described above is not limited to the wireless subscriber network (WLL) and is used to detect the synchronization signal of all systems using the CDMA system.

As described above, the present invention detects a plurality of synchronization signals in frame unit time by using a plurality of converted tap coefficients generated by a tap coefficient generator, and detects a position difference value of each synchronization signal by a sorting unit. There is an effect of outputting a synchronization signal having the smallest position difference and having the largest value.

In addition, it solves the problem of not detecting the synchronization signal due to the electromagnetic noise of the external environment, and improves the performance of the wireless subscriber network system by detecting the synchronization signal with accurate and high signal strength level even in the noisy environment. As a result, there is an industrial use effect that increases consumer confidence.

Claims (1)

A plurality of registers for sequentially receiving and outputting a synchronization signal of a pilot channel; A tap coefficient generator for sequentially generating and outputting a plurality of tap coefficients during a frame period of the pilot channel; A plurality of multipliers connected to the plurality of registers, respectively, to receive a synchronization signal and to multiply and output a plurality of tap coefficients respectively received from the tap coefficient generator; An adder configured to add and output all of the signals applied from the plurality of multipliers, respectively; And a sorting unit configured to classify the signal output from the adder and extract a synchronization signal having the highest level and the most optimal position.