JPH10190524A - Code generator and spread communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To establish the synchronization of gold codes in spread communication in an early stage by multiplying the output of first and second mask computing parts and outputting the gold codes. SOLUTION: A seed register 40 holds a fixed seed value and a long code generation part 41 turns the held seed value to an initial value, updates and generates a PN code every time a clock is supplied corresponding to a generation polynomial g (x) and supplies a PN code sequence at the time to a mask computing circuit 43. The seed register 44 holds the value (seed information) of the long code preceding phase information of an incoming link transmitted by a pilot channel and the long code generation part 45 turns the held seed value to the initial value, updates and generates the PN code every time the clock is supplied corresponding to the generation polynomial f(x) and supplies the PN code sequence at the time to the mask computing circuit 47. A multiplier 33 generates the gold code as a long code by multiplying the output of both mask computing circuits 43 and 47.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a code generator and a spread communication system, for example, Code Division Multiple Access (CDM).
A) may be applied to a communication system and its base station and mobile station code generators.

[0002]

2. Description of the Related Art For a CDMA communication system, for example, the following reference discloses the US standard system.

Reference: “Mobile Station-Base Station Co
mpatibility Standard for Dual-Mode Wideband Spread
Spectrum Cellular System, TIA / EIA / IS-
95, July 1993, U.S.A. S. A. The above document describes a radio interface between a mobile station and a base station in a CDMA communication system.

In a conventional CDMA communication system, CDM
As a method of generating a pseudo-random sequence code used as an A spreading code, an M sequence (maximum shift register sequence) is used as a periodic one used in a correlation technique. This code sequence has a feature that the correlation function is close to the delta function, is known to exhibit good autocorrelation characteristics, and has characteristics that it is easy to realize in hardware and is easy to control. I have.

In the CDMA system, a RAKE reception system in which a received wave is temporally separated and combined in code units of a spread code by despreading as a multipath countermeasure technique can be applied. R
In the AKE receiving method, a technique of selecting several paths having large power from a multipath signal and independently performing tracking and demodulation operations is essential.

[0006] This technique uses an arbitrary time (number) in time.
A shifted PN code is generated and despread by the PN code to search for a path having a large power, thereby realizing a multipath demodulation operation by despreading.

[0007]

However, a conventional CDMA communication system using a PN code generator using an M sequence has the following problems. That is,
The M-sequence random code has a good autocorrelation characteristic, but a large cross-correlation characteristic. Therefore, there is a problem that interference between other stations is large and a large number of CDMA multiplexes cannot be obtained.

Therefore, it is conceivable to apply a gold code having a good cross-correlation characteristic as a spreading code. However, the gold code generally has a very long period, and the gold code between the mobile station and the base station is generally used. How to establish early synchronization, especially synchronization in the uplink, remains as a technical issue.

[0009] Such a problem occurs not only in a CDMA communication system but also in a spread communication system using a one-to-one Gold code.

There is a need for a code generator for generating a gold code so as to be suitable for establishing gold code synchronization during spread communication and a spread communication system capable of realizing gold code synchronization early.

[0011]

In order to solve this problem, a first code generator according to the present invention comprises (1) first and second code generators.
(2) a first seed register storing a fixed value as seed information of the first M-sequence generator;
(3) a first mask register storing a fixed value, or a value obtained by calculating a generator polynomial of a first M-sequence generator for the fixed value, as a mask value; and (4) first M-sequence generation. A first mask operation unit for performing a mask operation process on the M-sequence output from the unit using the mask value stored in the first mask register; and (5) a second M-sequence generation unit. A second seed register storing, as seed information, a value representing an output phase of the code generator, which is externally provided;
(6) a second mask register storing a value obtained by calculating a generator polynomial of a second M-sequence generator for a fixed value as a mask value; and (7) an output from the second M-sequence generator. (8) multiplying the output of the first and second mask operation units by multiplying the M series by a second mask operation unit that performs a mask operation process using the mask value stored in the second mask register And a multiplier for outputting a Gold code.

The code generator according to the second aspect of the present invention has the following features.
A second M-sequence generator, (2) a first seed register storing a fixed value as seed information of the first M-sequence generator, and (3) a mask value, M of 1
A first mask control unit having an M-sequence generation configuration for generating a value obtained by calculating a generator polynomial of the sequence generation unit; and (4) a first M
A first mask operation unit for performing a mask operation process on the M sequence output from the sequence generation unit using the mask value output from the first mask control unit; (5) generating a second M sequence A second seed register storing an externally supplied value representing the output phase of the code generator as seed information of the unit, and (6) a second seed register as a mask value for a fixed value externally supplied. (2) a second mask control unit having an M-sequence generating configuration for generating a value obtained by calculating a generator polynomial of the M-sequence generating unit, and (7) an M-sequence output from the second M-sequence generating unit. (8) A gold code is output by multiplying the output of the first and second mask operation units by a second mask operation unit that performs a mask operation process using the mask value output from the second mask control unit. And a first and second
The phase shift control of the output Gold code can be performed by controlling the shift amount of the shift register in the mask control unit.

[0013] Further, a third aspect of the present invention relates to a spread communication system in which a second spread communication apparatus spreads transmission data of a predetermined channel using a Gold code as a spread code and transmits the spread data to the first spread communication apparatus. The code generator according to the second aspect of the present invention is applied as a code generator for generating a Gold code for synchronization acquisition and despreading processing in the first spread communication apparatus, and in the second spread communication apparatus, The code generator according to the first aspect of the present invention is applied as a code generator for generating a Gold code for spreading processing.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a code generator and a spread communication system according to the present invention are applied to a CDMA mobile communication system will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of the CDMA communication system according to this embodiment. As shown in FIG. 1, the CDMA communication system includes a base station and a plurality of mobile stations. In FIG. 1, the long code is represented by “LC” and the mask is represented by “MASK”.

The base station includes a pilot channel transmitting unit 1 for transmitting a short-period spread signal that defines a frame length, a common physical channel transmitting unit 2 for transmitting control data, and a transmitting / receiving voice and data. It comprises a transmitting unit 3 and a receiving unit 4 for a communication channel, and a receiving unit 5 for an access channel having a function of receiving control data from a mobile station.

The transmission units 1 to 3 and the reception units 4 and 5 of these channels are connected to a control processor 6 and controlled by the control processor 6. The transmission units 1 to 3 and the reception units 4 and 5 of these channels are provided with a high frequency unit (RF / IF).
7 is connected via an interface unit 8 to transmit and receive radio waves. The interface unit 8 operates as a synthesizer for synthesizing a CDMA spread code for a transmission channel, and operates as a distribution function unit for a reception channel.

On the other hand, the mobile station is configured to face the base station, and includes a pilot channel receiving section 10 for receiving a pilot signal and detecting a frame phase, and a common physical channel receiving section 11 for receiving control data. The mobile station comprises a receiving unit 12 and a transmitting unit 13 for transmitting and receiving call voice and data, and a transmitting unit 14 for an access channel having a function of transmitting control data from the mobile station.

The receiving units 10 to 12 and the transmitting units 13 and 14 of these channels are connected to a control processor 15 and controlled by the processor. The receiving units 10 to 12 and the transmitting units 13 and 14 of these channels are connected to the high-frequency circuit 1
7 is connected via an interface unit 16 to transmit and receive radio waves. The interface unit 16 operates as a combiner that combines CDMA spreading codes for a transmission channel, and operates as a combiner for a reception channel.
It operates as a distribution function unit.

The transmitting section 1 of the pilot channel in the base station has a function of transmitting a short-period spread signal defining a frame length, and other transmission channels (common physical channels and speech channels) coincide with the frame period. The transmission operation is performed in the form. The frame length is usually about 10 ms, and a PN code is generated with a cycle of 10 ms, and the data of the pilot channel is spread and transmitted.

On the other hand, the pilot channel receiving section 10 in the mobile station captures the pilot signal transmitted from the base station by a matched filter or a sliding correlator, thereby forming the pilot channel transmitting section 1 of the base station. The obtained frame period and phase are obtained. In addition, since other channels from the base station perform transmission operations in a form that matches the frame period, by acquiring this frame phase, the beginning of the frame becomes known, and a code corresponding to that is generated. And reception becomes possible.

The pilot channel of the base station has a mechanism for transmitting control data by a superframe structure in which several frames are combined, and the pilot channel transmitting unit 1 generates n superframes ahead of the superframe. It has a long code leading phase generator 20 for generating long code occurrence information, and has a long code leading phase and a downlink (a link from a base station to a mobile station).
And the mask information that defines the data of the long code Gold code of the long code. The long code leading phase defines the long code phase of the uplink (the link from the mobile station to the base station) (generation seed information of a long code that occurs n places ahead of the superframe), and the mask information is the downlink of the downlink. Defines the position of occurrence of the long code gold code.

Hereinafter, the processing and processing configuration of a long code in the CDMA communication system of this embodiment will be described.

FIG. 2 shows a flow of processing of a long code in the CDMA communication system of this embodiment.
In FIG. 2, the long code is represented by "LC" and the mask is represented by "MASK".

In the CDMA communication system of this embodiment, transmission / reception of a speech channel or a common physical channel is performed using a long code. Therefore, the system has a function of synchronizing transmission and reception of long codes.

The pilot channel transmitting section 1 of the base station includes:
It has an upstream long code leading phase generator 20 for generating the long code phase state of the upstream traffic channel. The long code phase of the uplink traffic channel generated by the generator 20 is used to match the phase of the long code between the mobile station and the base station in the uplink of the traffic channel. The generator 20 generates a state of an uplink long code occurring n superframes ahead for each superframe.

The common physical channel transmitting section 2 of the base station has a long code generator 21 with a mask function, and uses the long code (gold code) after the mask processing to convert the data of the common physical channel. The signal is spread and transmitted to the mobile station.

The communication channel transmitting unit 3 of the base station also has
It has a long code generator 22 with a mask function, and uses the long code (gold code) subjected to the masking process to perform spreading processing on downlink traffic channel data and transmits the data to the mobile station side.

Here, the pilot channel is, for example, 1
A long code generator 21 in the common physical channel transmitter 2 of the base station and a long code generator 22 in the traffic channel transmitter 3 have a frame configuration of a 0 ms cycle. , A long code is generated again, thereby enabling synchronous communication between the base station and the mobile station.

The mask information (downlink mask information; for example, base station ID) used by the common physical channel transmitter 2 and the traffic channel transmitter 3 of the base station in the masking process is transmitted to the mobile station using a pilot channel.

The upstream long code leading phase information received by the pilot channel receiving unit 10 of the mobile station is provided to the traffic channel transmitting unit 13 under the control of the control processor 15. The downlink mask information received by the pilot channel receiver 10 of the mobile station is provided to the common physical channel receiver 11 or the traffic channel receiver 12 under the control of the control processor 15.

The common physical channel receiving unit 11 of the mobile station
It has a long code generator 24 with a mask function, and uses the long code (gold code) subjected to the mask processing using the downlink mask information given from the base station to reverse the received data of the common physical channel. Perform diffusion processing.

The mobile station communication channel receiving section 12 has a long code generator 25 with a mask function, and performs a long code (Gold code) after performing a mask process using downlink mask information given from the base station. ), The received data of the downlink traffic channel is subjected to despreading processing.

Here, as described above, the pilot channel has a frame structure with a period of, for example, 10 ms, and includes a long code generator 24 in the common physical channel receiver 11 and a long code generator 24 in the traffic channel receiver 12. The generator 25 regenerates a long code from the start timing of the pilot frame data reception frame, thereby performing synchronous reception with the base station.

As described above, the uplink channel long-code leading phase information received by the pilot channel receiving section 10 is given to the traffic channel transmitting section 13 of the mobile station, and in addition to this, the ID of the mobile station is included in the mask information. Given as The long code generator 26 in the traffic channel transmitting unit 13 generates a long code (gold code) using uplink long code leading phase information and mask information using a mobile station ID, as described later. Using the long code, the communication channel transmitting section 13 of the mobile station performs spreading processing on the data of the uplink communication channel and transmits the data to the base station side.

The mobile station ID is stored in the access channel transmitting unit 1
4 is transmitted to the base station through the access channel. The mobile station ID received by the access channel receiving unit 5 of the base station is given to the traffic channel receiving unit 4 under the control of the control processor 6. The communication channel receiving section 4 is also provided with upstream long code leading phase information in the pilot channel transmitting section 1. This communication channel transmitting unit 4
The long code generator 23 generates a long code (gold code) using upstream long code preceding phase information and mask information using a mobile station ID, as described later. The traffic channel receiving unit 4 of the base station performs despreading processing on the received data of the uplink traffic channel using the long code.

FIG. 3 shows a detailed configuration of the upstream long code leading phase generator 20.

In FIG. 3, an upstream long code leading phase generator 20 includes a register 20a for storing seed information of a long code ahead of n superframes, and a long code seed from the value of this register 20a to n superframes ahead. And a preceding PN phase generator 20b that updates information for each superframe.

In the case of this embodiment, two types of pseudo-random sequence codes (P
N) is used, but a value determined by the time of one of the pseudo-random sequence codes is used as long code seed information for each superframe.

The method for updating the long code seed information n superframes ahead in the preceding PN phase generator 20b is as follows.

In the case of this embodiment, the leading PN phase generator 20b generates a pseudo-random sequence code as described above, and the pseudo-random sequence code has linearity. Therefore, the contents of the register when the time has elapsed by n superframes are changed to (Yn, Yn-
,..., Y0) and the contents of the current register to (Xn, Xn-
,..., X0), the upstream long code leading phase generator 20 outputs a fixed linear coefficient a for each superframe.
By executing the conversion formula shown in Expression (1) using i, j (i is 0 to n and j is 0 to n), it is possible to obtain long code seed information n superframes ahead.

Y0 = a0, nXn + a0, n-1 Xn-1 + ... + a0,0 X0Y1 = a1, n Xn + a1, n-1 Xn-1 + ... + a1,0 X0 ... Yn = an, n Xn + An, n-1 Xn-1 +... + An, 0 X0 (1) The output of the preceding PN phase generator 20b is connected so as to be fed back to the input of the register 20a. Superframe timing that occurs in the frame period is connected. Therefore, at each superframe timing, the seed information (upstream long code preceding phase information) for generating a long code n superframes ahead is always written in the register 20a.

As shown in FIG. 2, this upstream long code preceding phase information is broadcast to each mobile station using a superframe of a pilot channel. The mobile station receives this information and sets the initial value of the long code of the uplink traffic channel at the time of the determined superframe. Also, the uplink traffic channel of the base station sets the initial value of the long code using the uplink long code leading phase information.

In the case of this embodiment, 2 ³² is used for the uplink.
Use a long code (gold code) of -1 cycle.
This long code is used for the uplink traffic channel.

When a long code having a very long cycle is used and synchronization is simply established, it may take several days to establish synchronization. Therefore, the leading phase information of the long code used in the uplink is given from the base station to the mobile station,
In addition to generating a long code based on the phase information, the base station also generates a long code based on the phase information so that the synchronization of the long code can be established in a short time.

FIG. 4 is a block diagram showing the configuration of the long code generator 26 on the uplink transmission side of the traffic channel in the mobile station.

The long code generator 26 is composed of two PN code generators 31 and 32 each having a mask function and having different generator polynomials g (x) and f (x) having 2 ³² -1 periods. The multiplier 33 multiplies the outputs of the PN code generators 31 and 32 to generate a gold code as a long code.

The PN code generator 31 includes a seed register 4
0, a long code generator 41, a mask register 42, and a mask operation circuit 43.

The seed register 40 holds a seed value fixed to the mobile communication system, and the long code generator 41 sets the held seed value as an initial value, and obtains the following according to the generator polynomial g (x). The PN code is updated and generated each time the clock is supplied, and the PN code sequence at that time is supplied to the mask operation circuit 43 (the value of the internal shift register is output in parallel). In the mask register 42,
A fixed mask value (for example, all 1) is held in the mobile communication system. The mask operation circuit 43 outputs a parallel output Ai (i is 0 to 0) from the long code generation unit 41.
For i), a mask operation using the mask value Bi (i is 0 to i) held in the mask register 42 is performed, and the operation result is output to the multiplier 33.

The other PN code generator 32 includes a seed register 44, a long code generator 45, and a mask register 4.
6 and a mask operation circuit 47.

The seed register 44 holds the value (seed information) of the uplink long code leading phase information transmitted by the pilot channel (updated and held at the timing of the superframe). Using the held seed value as an initial value, the PN code is updated and generated every time a clock is applied according to the generator polynomial f (x), and the PN code sequence at that time is provided to the mask operation circuit 47 (internal The value of the shift register is output in parallel). In the mask register 46,
Mobile station-specific ID information is set. For example, as the value of the mask register 46, PN
An arithmetic operation of the generator polynomial f (x) of the code generator is used. The mask operation circuit 47 includes the long code generation unit 4
5, a mask operation using a mask value Bi (i is 0 to i) held in a mask register 46 is performed on the parallel output Ai (i is 0 to i), and the operation result is multiplied by a multiplier 33. Output to

The multiplier 33 is connected to both mask operation circuits 43
And 47 are output to generate a Gold code as a long code.

FIG. 5 is a block diagram showing an example of the configuration of the long code generator 45 (which may be applied to 41). Note that the long code generating section 41 also has a substantially similar configuration, although the generating polynomials are different, so that the insertion positions of the exclusive OR elements are different.

The long code generator 45 includes 32 registers SR1 to SR32 forming a shift register.
And exclusive OR elements ExOR1 to ExOR3, and generates an M-sequence PN signal by shifting a shift register. FIG. 5 shows a configuration in which exclusive OR elements ExOR1 to ExOR3 are inserted between shift registers (hereinafter referred to as an interpolation PN code generation circuit). An exclusive OR element ExO is connected between SR2.
R2 is provided between the registers SR2 and SR3, and an exclusive OR element ExOR3 is provided between the registers SR22 and SR23. Therefore, the signal generated by the long code generator 41 or 45 is generated by the generator polynomial P shown in the equation (2).
(X) (= g (x)).

P (x) = x ³² + x ²² + x ² +1 (2) FIG. 6 is a block diagram showing the configuration of the mask operation circuit 43 or 47 for realizing the mask function.

The mask operation circuit 43 or 47 performs an AND operation of the corresponding bits of the two input data Ai (i = 0 to i) and Bi (i = 0 to i) by AND elements AND0 to AND.
i, and the exclusive OR operation of all the outputs is performed by an exclusive OR element ExOR10, and the result is output as a mask output.

FIG. 7 is a block diagram showing the configuration of the long code generator 23 on the uplink receiving side of the traffic channel in the base station. The same and corresponding parts as in FIG. Is shown.

As is clear from the comparison between FIG. 7 and FIG.
The long code generator 23 on the receiving side is connected to the transmitting side (mobile station).
Has substantially the same configuration as the long code generator 26 of FIG.
The difference from the long code generator 26 on the transmitting side (mobile station) is that mask controllers 42A and 46A are applied instead of the mask registers 42 and 46.

Each of the mask control units 42A and 46A operates the mask value to be output, slides the gold code from the long code generator 23, and uses a sliding correlator (not shown) to generate a gold code sequence received from the mobile station. Is provided to enable the sliding correlation of

FIG. 8 shows the mask control unit 42A or 46A.
FIG. 5 is a block diagram illustrating a configuration example (here, described as 46A), on the assumption that the mobile station and the long code generation unit 45 of the base station are realized by the configuration example illustrated in FIG. 5 described above. Things.

The mask control section 46A includes 32 registers SR01 to SR032 constituting a shift register.
And exclusive OR elements ExOR01 to ExOR03, and generates an M-sequence PN signal by shifting a shift register. FIG. 8 shows a configuration in which exclusive OR elements ExOR01 to ExOR03 are inserted outside the shift register (hereinafter, referred to as an extrapolated PN code generation circuit). Exclusive OR element E
xOR01 is a register SR01 and an exclusive OR element E
The output of xOR02 is input and the exclusive OR output is given to the register SR01. The OR element ExOR02 receives the output of the register SR02 and the exclusive OR element ExOR03 and outputs the exclusive OR output to the exclusive OR. The exclusive OR element ExOR is provided to the OR element ExOR01.
03 receives the outputs of the registers SR022 and SR032, and outputs the exclusive OR output of the exclusive OR element Ex.
Give to OR02. Therefore, the signal generated by the mask control unit 46A is determined by the generator polynomial P (x) (= g (x)) shown in Expression (3), which is exactly the same as Expression (2) described above.

P (x) = x ³² + x ²² + x ² +1 (3) In the shift registers SR01 to SR032, the mobile station ID given as downlink mask information from the mobile station is set as an initial value. Also, the shift register SR01
０３SR032 are supplied from a control unit (not shown) for controlling a slide amount for sliding correlation, and a clock signal CCLK to the long code generation unit 45.
It can also be generated with a shorter cycle.
By generating the pulse signal UP, the phase of the Gold code output from the multiplier 33 can be delayed by one unit.

FIG. 9 is a block diagram showing another configuration example of the mask control section 46A. The mobile station and the long code generation section 45 of the base station are realized by the above-described configuration example shown in FIG. It is assumed that

The mask control section 46A shown in FIG. 9 has 32 registers SSRQ1-SSRQ32 each having a two-input selector and a D flip-flop.
And two exclusive OR elements ExOR11 and ExOR1
And 2. The 32 registers with selector SSRQ1 to SSRQ32 constitute a shift register capable of controlling the shift direction.

An exclusive OR element ExOR11 is connected to the A input terminal of the selector of the register SSRQ1 with selector at the first stage.
Is connected to the selector SS
The output terminal of the register SSRQ2 with selector at the next stage is connected to the B input terminal of the selector of RQ1. The output terminal of the exclusive OR element ExOR12 is connected to the B input terminal of the selector of the register SSRQ32 of the last stage, and the register SSR of the previous stage is connected to the A input terminal of the selector of the register SSRQ32.
The output terminal of Q31 is connected. Selector A of each intermediate register with selector SSRQj (j is 2-31)
The input terminal is a register SSRQj-1 with a selector at the preceding stage.
Is connected to the selector SS
The output terminal of the register SSRQj + 1 at the next stage is connected to the B input terminal of the selector of RQj.

The exclusive OR element ExOR11 has four registers SSRQ1, SSRQ2, SSRR with selector.
The outputs of Q22 and SSRQ32 are input, and the other exclusive OR element ExOR12 has 4
Registers with selector SSRQ1, SSRQ2, SS
The outputs of RQ3 and SSRQ23 are input.

The mask control unit 46A shown in FIG. 9 is a circuit similar to the circuit shown in FIG. 8, but realizes two types of functions in which the bit arrangement of the generator polynomial (the order of the MSB and LSB of the bits) is reversed. The shift direction of the shift register can be controlled according to whether the DIR signal given to the selection control terminal of the selector is "1" or "0". That is, the configuration shown in FIG. 9 can generate a lag phase and a lead phase of the Gold code. By setting the DIR signal to “1”, the A input terminal of the selector is selected,
The operation is the same as that of the circuit of FIG. 8. By setting the DIR signal to "0", the B input terminal of the selector is selected, the shift direction of the shift register is reversed, and the leading phase mask information can be generated.

As described above, in the long code generator 23 shown in FIG. 7, the reference PN code generator 41,
The output value of the shift register 45 and the mask control unit 42
The output values of the A and 46A shift registers are ANDed by the mask operation circuits 43 and 47, and then exclusive-ORed, thereby delaying one bit from the current time reference PN code, or A PN code with an advanced time phase can be generated, and a PN code with an arbitrary time phase shift can be generated by repeating the shift operation of the mask control units 42A and 46A.

Also, a gold code obtained by combining two PN codes can generate a gold code having an arbitrary time phase shift by operating the mask control units 42A and 46A.

This long code generator 23 is actually
It can be realized with a very small number of gate circuits, so that a circuit that can be implemented as an LSI and that does not cost much can be realized.

The following is a summary of the long code synchronization method for the uplink traffic channel of this embodiment.

A system time (seed information) of a reference long code is generated by a long code advance phase generator 20 of a base station, and this is generated by a superframe consisting of n times the frame period created from a pilot signal. In the configuration, the seed is transmitted to the mobile station, and the seed of the long code generator 26 of the traffic channel is set in the specified superframe n times ahead. The long code leading phase information is also specified in the uplink traffic channel of the base station. Since the long code generator 23 of the traffic channel sets the seed in the nth superframe ahead, the same seed information is transmitted at the same time in the traffic channel receiver 4 and the mobile station traffic channel transmitter 13 of the base station. Long code generator 2
3 and 26 can be set.

However, since the same time mentioned here does not include the time for radio wave propagation between the base station and the mobile station, the communication channel receiving unit 4 of the base station transmits the long code transmitted from the mobile station communication channel. Arrives after the time of radio wave propagation (round-trip time of about 6 μs).

To solve this, in this embodiment,
The configuration is such that the same mask code can be set in the long code generators 23 and 26 for transmitting and receiving a communication channel using the access channel. Since the mask information is different from the seed information of the long code leading phase, since it is just data, there is no strict restriction on time, and the long code generator 23 and the long code generator 23 of the mobile station and the base station are provided before the synchronization acquisition operation of the traffic channel starts. It suffices if it is set in the 26 mask registers 42 and 46 or the mask control units 42A and 46A. The setting of the mask information may be before or after setting the seed information.

The mask information set in the shift registers of the mask control units 42A and 46A of the communication channel receiving unit 4 of the base station is generated every time one pulse is input to the shift register clock signal UP of FIG. 8 or FIG. The generated Gold code is generated in a form that is slid in the lagging phase or the leading phase in time. By inputting this code to a sliding correlator (not shown) or the like and performing clock control of the shift register while observing a delay or advance profile, synchronization can be acquired.

Next, the common physical channel transmitting section 2 of the base station
The configuration of the long code generators 21 and 22 provided in the communication channel transmitter 3 will be briefly described.

Although not shown, it has a configuration substantially similar to the configuration of the long code generator 26 shown in FIG. In the following, with reference to the component code of FIG.

Unlike the long code generator 26, both the seed registers 40 and 44 of the long code generators 21 and 22 are set to fixed values in the system. Further, unlike the long code generator 26, a reset signal is input to the long code generators 41 and 45 of the long code generators 21 and 22, for example, every 10 ms. This reset timing is synchronized with the frame of the pilot channel. As the generator polynomials of the long code generators 41 and 45 of the long code generators 21 and 22, those having a period lower than that of the generator polynomial of the long code generator 26 are applied. Long code generator 2
The system fixed value (for example, all 1) is set in the mask register 43 of 1 or 22 in the same way as the long code generator 26, but the mask register 46 stores the mask value based on the base station ID. Is different from the long code generator 26.

Next, the common physical channel receiving section 1 of the mobile station
1 and the configuration of the long code generators 24 and 25 provided in the communication channel receiving unit 12 will be briefly described.

Although not shown, it has a configuration substantially similar to the configuration of the long code generator 23 of FIG. 7 described above. In the following, with reference to the component code of FIG.

Unlike the long code generator 26, fixed values are set in the seed registers 40 and 44 of the long code generators 24 and 25 in the system. Unlike the long code generator 23, for example, a signal obtained every 10 ms obtained from pilot channel data is input as a reset signal to the long code generators 41 and 45 of the long code generators 24 and 25. It has been made like that. As the generator polynomials of the long code generators 41 and 45 of the long code generators 24 and 25, those having a period lower than that of the generator polynomial of the long code generator 23 are applied. The point that a system fixed value (for example, all 1) is set in the mask register 43 of the long code generators 24 and 25 is the same as that of the long code generator 26, but the mask control unit 46A transmits a pilot channel. The point that the mask value encoded by the generator polynomial is output using the base station ID obtained as an initial value as the long code generator 2
3 and different.

According to the above embodiment, it is possible to quickly establish the synchronization of the Gold code at the time of spread communication such as an uplink communication channel.

Note that the present invention is not limited to the above embodiment, and various modifications are possible. As a variation,
For example, there is the following.

(1) In transmission of a long code leading phase, transmission on a pilot channel is not always necessary.
It is only necessary that each mobile station can be notified using a superframe synchronized with the basic frame of the pilot channel. Therefore, for example, transmission may be performed by a common physical channel.

(2) The PN code generator may be any circuit (any generator polynomial) and any value may be used as the reference PN code, as long as it is a circuit that generates the PN code of the M yarn string.

(3) The mask control unit uses the PN code generator M
Any circuit (any generator polynomial) may be used as long as it generates a series PN code, and any value is used as a reference P
The N code may be used.

(4) When the PN code generator inserts an exclusive OR between shift registers (hereinafter referred to as an interpolation PN code generation circuit), the mask information generator performs a shift operation. This can be realized in a form in which an exclusive OR is inserted outside the register (hereinafter, referred to as an extrapolation PN code generation circuit). When the PN code generator is realized by an extrapolation PN code generation circuit, the mask information generator can be realized by an interpolation PN code generation circuit.

(5) The seed register, the mask register, and the like need only store data of a predetermined number of bits, and may be a storage circuit such as a RAM.

(6) The present invention can be applied to a spread communication system using a one-to-one Gold code.

[0090]

As described above, according to the code generator and the spread communication system of the present invention, it is possible to quickly establish the synchronization of the Gold code during the spread communication.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a CDMA communication system according to an embodiment.

FIG. 2 is an explanatory diagram showing a flow of processing of a long code according to the embodiment;

FIG. 3 is an upstream long code advance phase generator 2 of the embodiment.
0 is a detailed block diagram of FIG.

FIG. 4 is a detailed block diagram of a long code generator 26 of the embodiment.

FIG. 5 is a detailed block diagram of a long code generation unit 45 of FIG.

6 is a detailed block diagram of the mask operation circuits 43 and 47 of FIG.

FIG. 7 is a detailed block diagram of a long code generator 23 of the embodiment.

FIG. 8 is a detailed block diagram of an example of a mask control unit 46A of FIG. 7;

FIG. 9 is a detailed block diagram of another example of the mask control unit 46A of FIG. 7;

[Explanation of symbols]

Reference numeral 20: upstream long code leading phase generator, 23: receiving long code generator, 26: transmitting long code generator, 33: multiplier, 40, 44 ... seed register, 4
1, 45: long code generator, 42, 46: mask register, 42A, 46A: mask controller, 43, 47 ...
Mask operation circuit.

Claims (5)

[Claims] 1. A first and second M-sequence generator, a first seed register storing a fixed value as seed information of the first M-sequence generator, and a fixed value or A first mask register storing a value obtained by calculating a generator polynomial of the first M-sequence generator for a fixed value; and a second mask for the M-sequence output from the first M-sequence generator. A first mask operation unit that performs a mask operation process using a mask value stored in the first mask register, and as a seed information of the second M-sequence generation unit, A second seed register storing a value representing an output phase; a second mask register storing a value obtained by calculating a generator polynomial of the second M-sequence generator for a fixed value as a mask value; From the second M-sequence generator A second mask operation unit for performing a mask operation process on the output M-sequence using the mask value stored in the second mask register, and an output of the first and second mask operation units And a multiplier that outputs a Gold code by multiplying the multiplication by 2. A first and second M-sequence generator, a first seed register storing a fixed value as seed information of the first M-sequence generator, and a mask value for the fixed value. A first mask control unit having an M-sequence generation configuration for generating a value obtained by calculating a generator polynomial of the first M-sequence generation unit; and a M-sequence output from the first M-sequence generation unit. A first mask operation unit that performs a mask operation process using a mask value output from the first mask control unit; and a code externally given as seed information of the second M-sequence generation unit. A second seed register storing a value representing the output phase of the generator, and a fixed value externally given as a mask value,
A second mask control unit having an M-sequence generation configuration for generating a value obtained by calculating a generator polynomial of the second M-sequence generation unit; and an M-sequence output from the second M-sequence generation unit, A second mask operation unit that performs a mask operation process using the mask value output from the second mask control unit; and a gold code output by multiplying the output of the first and second mask operation units. A code generator comprising: a multiplier; and a phase shift control of an output Gold code by controlling a shift amount of a shift register in the first and second mask control units. 3. A spread communication system in which a second spread communication apparatus spreads spectrum of transmission data of a predetermined channel using a Gold code as a spread code and transmits the spread data to a first spread communication apparatus. The code generator according to claim 2 is applied as a code generator for generating a Gold code for synchronization acquisition and despreading processing in the apparatus, and for the spreading processing in the second spreading communication apparatus. A spread communication system, wherein the code generator according to claim 1 is applied as a code generator for generating a Gold code. 4. The second spread communication apparatus transmits, to the first spread communication apparatus, information of a value set in a second mask register of its own code generator, a channel different from the predetermined channel. Wherein the first spread communication apparatus is configured to transmit the mask information transmitted by
2. The spread communication system according to claim 1, further comprising a mask information receiving unit configured to set information on a value transmitted by the mask information transmitting unit in the mask control unit. 5. The first spread communication apparatus transmits the gold code phase information of the future time to the second spread communication apparatus and supplies the second spread communication apparatus to its own code generator.
The second spreading communication apparatus supplies the transmitted gold code phase information of the future time to its own code generator and sets the second code in the second spread communication apparatus. The spread communication system according to claim 3, further comprising a preceding phase generation receiving unit configured to set the seed register in a seed register.