KR19990061358A - Initial Acquisition Device of Broadband CDA Mobile Communication System - Google Patents

Abstract

The present invention relates to an initial synchronization acquisition device of a wideband code division multiple access mobile communication system for matching a first PN code string input through a pilot channel with a phase of a second PN code string generated therein. When the second PN code sequence is repeatedly output in groups and sequentially outputted, and when a plurality of consecutive PN codes of the second PN code sequence are loaded, the second PN code sequence of the second PN code sequence starts from the loaded PN code. A PN code generator 110 to start generation; Detects a correlation value between the first PN code string received from the pilot channel and the second PN code string output from the PN code generator 110, and controls the PN code generator 110 to control the PN code generator. A correlator 120 for shifting the second PN code string provided from 110 by one chip; A code memory (130) for storing a predetermined number of PN codes of upper ranks among the second PN code strings generated by the PN code generator (110); After loading the initial value of the second PN code sequence for initial synchronization acquisition into the PN code generator 110, the correlation values corresponding to each phase of the second PN code sequence are received from the correlator 120 and compared with each other. Determine the highest correlation value, and read a predetermined number of PN codes from the code memory 130 from the start point of the PN code sequence corresponding to the phase of the second PN code sequence in which the correlation value is highest. A processor 100 for loading into the generator 110; When the phase of the second PN code sequence generated by the PN code generator 110 is shifted, the number of phase shifts thereof is counted, and when the phase comparison with respect to one group of the second PN code sequence is completed, the processor 100 performs a comparison. A code memory control unit (140) for controlling the PN code storage time of the code memory (130); And a synchronous clock generator 150 generating a synchronous clock and providing the synchronous clock to the PN code generator 110 and the code memory controller 140.

Description

Initial Acquisition Device of Broadband CDA Mobile Communication System

The present invention provides an initial synchronization for finding synchronization of a received signal at a mobile station or a base station by using a pilot channel transmitted from a base station or a terminal of a wideband code division multiple access (CDMA) mobile communication system. An acquisition device.

In general, finding the correct synchronization in a wideband CDMA mobile communication system is an important factor in determining the performance of the system. Therefore, the communication method in the wideband CDMA mobile communication system has many differences from the general communication method. Among them, the method of spreading the signal is much wider than the frequency band of the original signal in the modulation method.

Accordingly, if the spreading signal at the receiving end is not despread to the original narrow band, since the information to be transmitted at the transmitting end is not properly transmitted, it does not have any meaning, so the receiving end must despread the spreading signal at the time of transmission. do.

To do this, the following two prerequisites must first be established. First, the pattern of the PN code used to spread the signal during transmission must match the code used at the receiving end, and secondly, the PN generated at the receiving end. The code is to be synchronized with the PN code included in the received signal.

That is, the receiver can recover data by synchronizing the PN code only when the PN code patterns generated by the transceiver are identical.

In addition, the synchronization process is basically divided into two parts, the initial synchronization acquisition process and the synchronization tracking process, and the method of selection is different depending on the required characteristics.

That is, a method of preventing the PN synchronization from deviating by more than one chip when despreading the band by using the same code used to spread the band at the reception side is an initial synchronization acquisition process. After the process, the synchronization tracking process is to adjust the reference signal of the receiver so that the PN code pattern used by the transmitter does not differ by more than one chip.

Herein, a detailed description of the conventional initial synchronization acquisition process is as follows. That is, the transmitting end of the wideband CDMA mobile communication system transmits the first PN code string through a pilot channel, and transmits the PN code string consisting of M (M; integer) bits into one group and repeats iteratively in group units. do.

In addition, the receiving end of the broadband CDMA mobile communication system generates a second PN code string identical to the PN code string generated at the transmitting end, and then compares the phase with the first PN code string received through the pilot channel. At this time, the phase comparison is received from the pilot channel by detecting a correlation value between the first PN code string and the second PN code string in each phase while shifting the phase of the second PN code string generated at the receiving end by one chip unit. The first PN code sequence and the second PN code sequence are searched for the phase where the correlation value is highest. Here, the position where the correlation value between the first PN code string and the second PN code string is highest is the phase synchronization.

Subsequently, when a search for a phase in which the correlation value between the first PN code string and the second PN code string received from the pilot channel is highest is completed, the receiver stores the phase and delays generation of the second PN code string. The generation of the second PN code string is resumed when the phase between the first PN code string and the second PN code string is synchronized.

However, such a conventional initial synchronization acquisition process is delayed for a predetermined time in order to synchronize the phase between the first PN code sequence received from the pilot channel and the second PN code sequence generated at the receiving end. There was a long time issue.

The present invention has been made to solve the above problems, and an object thereof is to provide an initial synchronization acquisition device of a CDMA mobile communication system which can further shorten the initial synchronization acquisition process time.

In order to achieve the above object, the present invention provides an apparatus for initial synchronization acquisition of a wideband code division multiple access mobile communication system in which a first PN code sequence input through a pilot channel matches a phase of a second PN code sequence generated therein. Generating the second PN code sequence, and sequentially outputting the second PN code sequence in group units, and when a plurality of consecutive PN codes of the second PN code sequence are loaded, the loaded PN code A PN code generator for starting the generation of the second PN code string from the first; A second PN code provided from a PN code generator by detecting a correlation value between the first PN code string received from the pilot channel and the second PN code string output from the PN code generator, by controlling the PN code generator; A correlator for shifting columns by one chip; A code memory for storing a predetermined number of upper PN codes in the second PN code strings generated by the PN code generator; After loading the initial value of the second PN code sequence for initial synchronization acquisition to the PN code generator, the correlation values corresponding to each phase of the second PN code sequence are received from the correlator and compared with each other to obtain the highest correlation value. A processor configured to determine and read a predetermined number of PN codes from the code memory from the start point of the PN code sequence corresponding to the phase of the second PN code sequence having the highest correlation value and load them into the PN code generator; Each time the phase of the second PN code sequence generated by the PN code generator is shifted, the number of phase shifts thereof is counted, and when the phase comparison of one group of the second PN code sequence is completed, the code is provided to the processor. A code memory control unit controlling a PN code storage time point of the memory; And a synchronous clock generator for generating a synchronous clock and providing the PN code generator and the code memory controller.

1 is a view showing an initial synchronization acquisition device according to a preferred embodiment of the present invention;

2 is an illustration for explaining an operating state according to the embodiment of FIG.

Explanation of symbols for main parts of the drawings

100; Processor 110; PN code generator

120; Correlator 130; Code memory

140; Code memory control unit 150; Synchronous signal generator

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

Figure shows an initial synchronization acquisition device of a CDMA mobile communication system according to a preferred embodiment of the present invention. In FIG. 1, an initial synchronization acquisition device of a CDMA mobile communication system includes a processor 100, a PN code generator 110, a correlator 120, a code memory 130, a code memory controller 140, and a synchronization signal generator ( 150).

Here, although not shown in the figure, the PN code generator 110 is composed of a linear feedback shift register including an N-stage register and a logic gate, so that a second M bit is composed of one group. PN code string is outputted by repeating iteratively in group units.

In addition, the PN code generation unit 110, if a consecutive PN code of N (N; integer, N < M) in one group is loaded from the processor 100 among the second PN code strings in group units, then the PN code generation unit 110 starts. The generation of the second PN code string is started.

The correlator 120 detects a correlation between the first PN code string received from the pilot channel and the second PN code string provided from the PN code generator 110, provides the result to the processor 100, and provides the PN code. The generator 110 is controlled to shift the second PN code string provided from the PN code generator 110 in units of one chip.

The code memory 130 stores Y (Y; integer) codes that are initially generated among the second PN code strings generated by the PN code generator 110. The code memory controller 140 controls a time point for storing the PN code of the code memory 130. The sync signal generator 150 generates a sync clock and provides the sync clock to the PN code generator 110 and the code memory controller 140.

The processor 100 provides an initial value of the PN code string for initial synchronization acquisition to the PN code generator 110, and provides an operating state of the correlator 120 provided from the code memory controller 140 and the correlator 120. The initial synchronization acquisition of the system is controlled based on the correlation result.

The operation of the initial synchronization acquisition apparatus of the CDMA mobile communication system according to the preferred embodiment of the present invention configured as described above is as follows.

First, the processor 100 loads an initial value of N bits of the second PN code sequence for initial synchronization acquisition into the PN code generator 110. When the PN code generator 110 loads the initial value of the PN code string, the PN code generator 110 sequentially synchronizes the second PN code string composed of M (M; integer) bits for initial synchronization acquisition in synchronization with the synchronization clock provided from the synchronization signal generator 150. Occurs as

That is, the PN code generation unit 110 includes N-stage registers and logic gates, and a predetermined logic gate logically combines the outputs of selected K (K; integer) registers among N-stage registers. In order to feed back to the input of the register, if the upper N bits of the second PN code sequence consisting of M bits are loaded in one-to-one correspondence to the N-stage register, the second PN code sequence consisting of M bits is traversed in group units. Is output. For example, the PN code to be generated in the PN code generator 110 D ₁ , D ₂ , D ₃ , D ₄ , D ₅ , D ₆ ,. , D _M If, D ₁ , D ₂ , D ₃ ,. D _N The code of is loaded in one-to-one correspondence into the N registers. Then, the code output from the PN code generator 110 D ₁ , D ₂ , D ₃ ,. , D _N , D _{N + 1} ,... D _M , D ₁ , D ₂ ,. As described above, the second PN code string is output while being circulated.

On the other hand, the correlator 120 controls the PN code generator 110 to control the second PN code string provided from the PN code generator 110 to be shifted by one chip, while the first received from the pilot channel. The correlation between the PN code sequence and the second PN code sequence provided from the PN code generator 110 is detected and the results are provided to the processor 100. In this case, the number of bits used to detect the correlation value once in the correlator 120 is not the entire group of PN code strings, but only L (L; integer) bits of the M bit PN code strings are applied, and M = L. n- (n-1) (n; integer)

Whenever the phase of the second PN code string generated by the PN code generator 110 is shifted, the code memory controller 140 counts the number of phase shifts of the second PN code string to generate the second PN code string generated by the PN code generator 110. When the phase comparison for one group is completed, it is provided to the processor 100. In other words, since the number L of bits used for detecting the correlation value once in the correlator 120 has a relationship of M = L * n− (n−1), the PN code generator 110 generates the first number of bits. When the phase shift of two PN code sequences is performed n-1 times, the correlation comparison with respect to one group of the second PN code sequences is completed, and thus, the processor 100 provides a state thereof. In addition, the correlator 120 controls the code memory 130 to store the upper Y PN codes of the second group of PN codes formed of M bits generated by the PN code generator 110.

Therefore, for example, the second PN code string generated in the PN code generator 110 may be, for example, D ₁ , D ₂ , D ₃ ,. , D _N , D _{N + 1} ,... D _M , D ₁ , D ₂ ,. In the code memory 130, the top Y PN codes, i.e. D ₁ , D ₂ , D ₃ ,. , D _N , D _{N + 1} ,... , D _Y The code for is stored.

Meanwhile, the processor 100 stores a correlation value corresponding to each phase of the second PN code string in an internal memory, compares the stored correlation values with each other, detects the highest correlation value, and then, from the code memory controller 140, Based on the provided count value, the phase of the second PN code string having the highest correlation value is determined.

Here, a phase shift of the second PN code string output from the PN code generator 110 will be described with reference to FIG. 2 as follows. That is, for example, the second PN code string output from the PN code generator 110 is D ₁ , D ₂ , D ₃ , D ₄ , D ₅ , D ₆ ,. , D _M , D ₁ , D ₂ ,.. In the case of (Fig. 2a), if this is a one-chip phase shift, D ₂ , D ₃ , D ₄ , D ₅ , D ₆ ,. , D _M , D ₁ , D ₂ , D ₃ ,. It becomes the code string like (FIG. 2B). Also, if the second PN code string output from the PN code generator 110 is shifted two-chip, D ₃ , D ₄ , D ₅ , D ₆ ,. , D _M , D ₁ , D ₂ , D ₃ , D ₄ ,. It becomes the code string like (FIG. 2C).

On the other hand, as described above, the PN code generation unit 110 has a different phase of the second PN code string outputted according to the PN code loaded from the outside.

E.g, D ₁ , D ₂ , D ₃ ,. , D _N When the code of the PN code generator 110 is loaded, the PN code generator 110 D ₁ , D ₂ , D ₃ ,. , D _N , D _{N + 1} ,... , D _M , D ₁ ,… Outputs the PN code string.

Also D ₂ , D ₃ , D ₄ ,. , D _N, D _{N + 1} When the code of the PN code generator 110 is loaded, the PN code generator 110 D ₂ , D ₃ ,. , D _N , D _{N + 1} ,... , D _M , D ₁ ,… Outputs the PN code sequence of D ₁ , D ₂ , D ₃ ,. , D _N , D _{N + 1} ,... , D _M , D ₁ ,… Phase difference of 1 chip with the PN code generator 110 D ₃ , D ₄ ,... , D _N, D _{N + 1} , D _{N + 2} When the code of the PN code generator 110 is loaded D ₃ , D ₄ ,... , D _N , D _{N + 1} ,... , D _M , D ₁ ,… Outputs the PN code sequence of D ₁ , D ₂ , D ₃ ,. , D _N , D _{N + 1} ,... , D _M , D ₁ ,… Phase difference between the two chips.

Therefore, the processor 100 determines the phase of the second PN code string having the highest correlation value based on the count value provided from the code memory controller 140, and then determines the phase of the second PN code string having the highest correlation value. The PN code sequence corresponding to the PN code sequence is detected, and the PN code generator 110 reads the PN code from the start point of the PN code sequence corresponding to the phase of the second PN code sequence having the highest correlation value from the code memory 130. By loading directly into), the initial sync acquisition is completed.

For example, the second PN code is a result of detecting the correlation with the first PN code string received from the pilot channel while phase shifting the second PN code string provided from the PN code generator 110 in units of one chip. If the highest correlation value is detected when the column is phase shifted twice, the second PN code string generated by the initial value first loaded into the PN code generator 110 by the processor 100 is equal to the first PN code string. There is a phase difference as much as the chip.

Thus, the processor 100 may store PN codes stored in the code memory 130, for example. D ₁ , D ₂ , D ₃ ,. , D _N , D _{N + 1} ,... , D _Y In the code of, D ₃ ,.. , D _N , D _{N + 1} , D _{N + 2} After the PN code is detected and reloaded into the PN code generator 110, the second PN code string output from the PN code generator 110 is equal to the result of phase compensation of two chips.

Accordingly, the phases of the first PN code string received from the pilot channel and the second PN code string output from the PN code generator 110 coincide with each other to complete initial synchronization acquisition.

As described above, according to the present invention, the first PN code sequence and the PN code received from the pilot channel are stored in the code memory 130 among the second PN code sequence generated by the PN code generator 110. After detecting the phase with the highest correlation value of the second PN code string output from the generation unit 110, the PN code string corresponding to the phase of the second PN code string having the highest correlation value is read from the code memory 130. By loading the PN code memory 110, it is possible to perform initial synchronization acquisition more quickly.

Claims (1)

In an initial synchronization acquisition device of a wideband code division multiple access mobile communication system for matching a first PN code string input through a pilot channel with a phase of a second PN code string generated internally: The second PN code string is generated, and the second PN code string is sequentially outputted by repeatedly iterating in group units, and when a plurality of consecutive PN codes are loaded in the second PN code string, A PN code generator 110 for starting the generation of the second PN code string; Detects a correlation value between the first PN code string received from the pilot channel and the second PN code string output from the PN code generator 110, and controls the PN code generator 110 to control the PN code generator. A correlator 120 for shifting the second PN code string provided from 110 by one chip; A code memory (130) for storing a predetermined number of PN codes of upper ranks among the second PN code strings generated by the PN code generator (110); After loading the initial value of the second PN code sequence for initial synchronization acquisition into the PN code generator 110, the correlation values corresponding to each phase of the second PN code sequence are received from the correlator 120 and compared with each other. Determine the highest correlation value, and read a predetermined number of PN codes from the code memory 130 from the start point of the PN code sequence corresponding to the phase of the second PN code sequence in which the correlation value is highest. A processor 100 for loading into the generator 110; When the phase of the second PN code sequence generated by the PN code generator 110 is shifted, the number of phase shifts thereof is counted, and when the phase comparison with respect to one group of the second PN code sequence is completed, the processor 100 performs a comparison. A code memory control unit (140) for controlling the PN code storage time of the code memory (130); An initial synchronization acquisition device of a wideband code division multiple access mobile communication system including a synchronization clock generator (150) for generating a synchronization clock and providing the PN code generator (110) to the code memory controller (140).