Method for updating linear feedback shift register of code generator

(54) METHOD FOR UPDATING LINEAR

FEEDBACK SHIFT REGISTER OF CODE
GENERATOR

(75) Inventors: Veli Lipponen, Helsinki (FI); Pentti
Moilanen, Oulu (FI)

(73) Assignee: Nokia Networks Oy, Espoo (FI)

( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.

(21) Appl. No.: 09/903,867

(22) Filed: Jul. 13, 2001

(65) Prior Publication Data

US 2002/0031169 Al Mar. 14, 2002

Related U.S. Application Data

(63) Continuation of application No. PCT/FI00/00236, filed on Mar. 22, 2000.

(30) Foreign Application Priority Data

Mar. 23, 1999 (FI) 990649

(51) Int. CI.7 H04L 27/30; A61H 2/06;

H04B 7/216

(52) U.S. CI 375/150; 375/130; 375/152;

370/335

(58) Field of Search 375/130, 150,

375/152; 370/335

(56) References Cited

U.S. PATENT DOCUMENTS

5,228,054 A * 7/1993 Rueth et al 708/252

5,243,622 A 9/1993 Lux et al.

5,267,271 A * 11/1993 Rice 375/343

5,596,571 A * 1/1997 Gould et al 370/335

5,761,239 A 6/1998 Gold et al.

6,005,888 A * 12/1999 Barron 375/208

6,014,408 A 1/2000 Naruse et al.

6,061,338 A * 5/2000 O 370/335

6,141,374 A * 10/2000 Burns 375/152

6,246,697 Bl * 6/2001 Whinnett et al 370/479

6,459,722 B2 * 10/2002 Sriram et al 375/130

6,470,000 Bl * 10/2002 Burns et al 370/342

FOREIGN PATENT DOCUMENTS

EP 940 928 9/1999

EP 955 734 11/1999

WO WO 96/36137 11/1996

WO WO 99/35564 7/1999

OTHER PUBLICATIONS

Cruselles et al, Uncorrelated PN Sequences Generator for Speading Codes in CDMA Systems, IEEE 1995, pp. 296-298.*

Grant et al, Spread-Spectrum PN-Coded Waveform Detection For Communication ESM, IEEE, 1994, pp. 4/1-4/4.*

* cited by examiner

Primary Examiner—Mohammad H. Ghayour

Assistant Examiner—-Tony Al-Beshrawi

(74) Attorney, Agent, or Firm—Pillsbury Winthrop LLP

(57) ABSTRACT

The invention relates to method and code generator for updating linear feedback shift register (LFSR). The method comprises defining jumps corresponding to different powers of two for shifting from known state to new state. Then in each jump the LFSR obtained as a result of the jump in question is generated: the value of one element of the obtained LFSR is generated from the previous state and the pre-stored mask register corresponding to said obtained element, while the mask register determines the elements of the LFSR of the previous state, using which elements said element value is generated, and the generation of the value of one LFSR element is repeated for each remaining obtained feedback LFSR by shifting the mask register to the position of said remaining element and by generating the value of said remaining element of the obtained LFSR from the previous state and the shifted mask register.

14 Claims, 14 Drawing Sheets