PN code generating apparatus and mobile radio communication system

• US 6,295,301 B1
• Filed: 08/25/1998
• Issued: 09/25/2001
• Est. Priority Date: 09/02/1997
• Status: Expired due to Term

• Current Assignee: INVT SPE LLC (SoftBank Group Corp.)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Asano, Nobuo
• Primary Examiner(s): CANGIALOSI, SALVATORE A
• Application Number:
  US09/139,325
• Time in Patent Office: 1,127 Days
• Field of Search: 331/78, 708/253, 380/46, 375/206, 370/342, 370/514, 370/515
• US Class Current: 370/514
• CPC Class Codes: G06F 7/584 using finite field arithmetic, e.g. using a linear feedback shift register
• CPC Class Codes: H03K 3/84 Generating pulses having a predetermined statistical distribution of a parameter, e.g. random pulse generators
• CPC Class Codes: H04J 13/0022 PN, e.g. Kronecker
• CPC Class Codes: H04J 13/10 Code generation
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

In a PN code generating apparatus, a code of the predetermined number of stages is generated using primitive polynomial G(x), then the code content of each stage is shifted to the next stage. And a state setting section obtains a code state of the PN code generating section after shifted the specific times from a code state of the PN code generating apparatus at a certain time, based on xⁱmodG(x) as the number of shift times is i.

Claims

1. A PN code generating apparatus comprising:

a shift register that generates a PN code, said shift register having a plurality of serial connected delay elements, wherein the number of said delay elements corresponds to the number of orders of a primitive polynomial G(x), a plurality of exclusive ORs each at an input stage of one of said delay elements, and a plurality of multipliers that multiply a feedback code outputted from a predetermined delay element by a coefficient of each order of said primitive polynomial G(x) so as to input each multiplied value to an exclusive OR corresponding to the order respectively;

a generator that generates a masking polynomial S(x) based on the following formulation;

2. The PN code generating apparatus according to claim 1, wherein said generator calculates the number of shift times “

i”

at which said shift register should be shifted during a period from termination of a PN code generation operation to restarting of the operation.

3. The PN code generating apparatus according to claim 1, wherein said generator stores the number of shift times “

i”

at which said shift register should be shifted during a period from termination of a PN code generation operation to restarting of the operation.

4. The PN code generating apparatus according to claim 1, said generator further comprising:

a storage that stores a plurality of masking polynomials S(x) pre-calculated corresponding to a plurality of the number of shift times “

i”

or information concerning each order of the masking polynomial S(x); and

a selector that selects one of a masking polynomial S(x) and information concerning each order of the masking polynomial from said storage.

5. The PN code generating apparatus according to claim 1, said generator further comprising:

a storage that stores a plurality of masking polynomials S(x) pre-calculated corresponding to a plurality of the number of shift times “

i”

or information concerning each order of the masking polynomial S(x); and

a selector that selects one of a masking polynomial S(x) and information concerning each order of the masking polynomial from said storage based on a value of n as n×

T (n is an integer and T is a unit time) is a period time from the first time to the second time.

6. The PN code generating apparatus according to claim 5, wherein said selector selects S(x) corresponding to one of mⁱ×

T and information concerning an order of the S(x) by sequentially increasing a value of “

i”

as n=mⁱ.

7. The PN code generating apparatus according to claim 1, said state setting system comprising:

a parallel/serial converter that serial outputs a plurality of bit data saved in parallel, while saving in parallel, memory bit data of said each delay element indicative of a state of said shift register at said first time; and

a plurality of ANDs corresponding to each of said exclusive ORs for calculating a logic product of bit data outputted from said parallel/serial converter and each order of said S(x) to input the logic product to a corresponding exclusive OR.

8. A mobile station apparatus in radio communication with a base station in a CDMA system, said mobile station apparatus comprises a PN code generating apparatus according to claim 1.

9. A base station apparatus in radio communication with a mobile station apparatus, said base station apparatus comprises the PN code generating apparatus according to claim 1.

10. A method for generating a PN code using a shift register, wherein said shift register has a plurality of serial connected delay elements, the number of said delay elements corresponding to the number of orders of a primitive polynomial G(x), a plurality of exclusive ORs each at an input stage of one of said delay elements, and a plurality of multipliers that multiply a feedback code output from a predetermined delay element by a coefficient of each order of said primitive polynomial G(x) so as to input each multiplied value to an exclusive OR corresponding to the order, said method comprising:

generating a masking polynomial S(x) based on the following formulation;

11. A computer program product for operating a computer, said computer program product comprising:

a computer readable medium;

a first program instruction system that instructs a computer processor to shift a plurality of bit data forming a code to a next storage according to a shift clock, and to multiply a coefficient of each of the specific orders of a primitive polynomial G(x) by bit data to which the order corresponds so as to generate a new code; and

a second program instruction system that instructs a computer processor to obtain a state of a code after being shifted a predetermined number of times from a state of said code at a certain time based on xⁱmodG(x) where the number of shift times is i, and wherein each of said program instruction systems are recorded on said medium in an executable form and are loadable into a computer memory for execution by the associated processor.

12. A PN code generating apparatus comprising:

a PN code generator that generates a PN code;

a calculator that calculates a polynomial corresponding to a number of shift times during a period from when said PN code generator is turned off to when said PN code generator is turned on; and

a system that obtains a state of said PN code generator immediately after said PN code generator is turned on using said polynomial corresponding to the number of shift times and another state of said PN code generator immediately before said PN code generator is turned off;

wherein said PN code generator can be turned off during a non-reception period.

13. A PN code generating method comprising:

generating a PN code;

calculating a polynomial corresponding to a number of shift times to be obtained during a period corresponding to a time the PN code generation is turned off and then turned on;

obtaining, based upon the polynomial and a state of said PN code generation at the time said PN code generation is turned off, a state of the PN code generation when the PN code generation is turned on; and

turning off the PN code generation during a non-reception period.