Rapid acquisition spreading codes for spread-spectrum communications

• US 6,985,467 B2
• Filed: 01/10/2001
• Issued: 01/10/2006
• Est. Priority Date: 06/30/1995
• Status: Expired due to Term

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Ozluturk, Fatih, Kowalski, John, Silverberg, Avi, Jacques, Alexander, Lomp, Gary, Marra, Alexander, Luddy, Michael, Regis, Robert
• Primary Examiner(s): NGUYEN, BRIAN D
• Application Number:
  US09/757,768
• Publication Number:
  US 20030193914A1
• Time in Patent Office: 1,826 Days
• Field of Search: 370/335, 370/320, 370/328, 370/329, 370/342, 370/203, 370/204, 370/206, 370/208, 370/210, 370/441, 370/479, 370/310, 370/318, 370/465, 370/468, 375/130, 375/140, 375/146, 375/147
• US Class Current: 370/335
• CPC Class Codes: G06F 13/374 using a self-select method with individual priority code comparator
• CPC Class Codes: H03H 17/0226 comprising look-up tables
• CPC Class Codes: H03H 17/06 Non-recursive filters
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 1/7075 with code phase acquisition
• CPC Class Codes: H04B 1/70753 Partial phase search
• CPC Class Codes: H04B 1/70754 Setting of search window, i.e. range of code offsets to be searched H04B1/70758 takes precedence
• CPC Class Codes: H04B 1/70755 Setting of lock conditions, e.g. threshold
• CPC Class Codes: H04B 1/70758 Multimode search, i.e. using multiple search strategies
• CPC Class Codes: H04B 1/7077 Multi-step acquisition, e.g. multi-dwell, coarse-fine or validation
• CPC Class Codes: H04B 1/708 Parallel implementation
• CPC Class Codes: H04B 1/7085 using a code tracking loop, e.g. a delay-locked loop
• CPC Class Codes: H04B 1/709 Correlator structure
• CPC Class Codes: H04B 1/7093 Matched filter type
• CPC Class Codes: H04B 1/711 the interference being multi-path interference
• CPC Class Codes: H04B 1/7115 Constructive combining of multi-path signals, i.e. RAKE receivers
• CPC Class Codes: H04B 1/712 Weighting of fingers for combining, e.g. amplitude control or phase rotation using an inner loop
• CPC Class Codes: H04B 2201/70701 featuring pilot assisted reception
• CPC Class Codes: H04B 2201/70702 Intercell-related aspects
• CPC Class Codes: H04B 2201/70703 using multiple or variable rates
• CPC Class Codes: H04B 2201/70707 : Efficiency-related aspects
• CPC Class Codes: H04B 2201/7071 : with dynamic control of receiver resources
• CPC Class Codes: H04B 7/2628 : using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA] H04B7/2618 takes precedence
• CPC Class Codes: H04B 7/2637 : for logical channel control
• CPC Class Codes: H04B 7/264 : for data rate control
• CPC Class Codes: H04J 13/00 : Code division multiplex systems for frequency hopping H04B1/713
• CPC Class Codes: H04J 13/004 : Orthogonal
• CPC Class Codes: H04J 13/0048 : Walsh
• CPC Class Codes: H04J 13/0077 : Multicode, e.g. multiple codes assigned to one user
• CPC Class Codes: H04J 13/10 : Code generation
• CPC Class Codes: H04J 13/107 : by concatenation
• CPC Class Codes: H04J 13/12 : Generation of orthogonal codes
• CPC Class Codes: H04J 13/16 : Code allocation
• CPC Class Codes: H04J 2013/0037 : Multilevel codes
• CPC Class Codes: H04L 1/0001 : Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• CPC Class Codes: H04L 1/004 : by using forward error control H04L1/0618 takes precedence; coding, decoding or code conversion, for error detection or correction H03M13/00
• CPC Class Codes: H04L 1/0042 : Encoding specially adapted to other signal generation operation, e.g. in order to reduce transmit distortions, jitter, or to improve signal shape H04L1/0067 takes precedence
• CPC Class Codes: H04L 1/0047 : Decoding adapted to other signal detection operation in conjunction with sequence estimation or equalization H04L25/03286
• CPC Class Codes: H04L 1/0054 : Maximum-likelihood or sequential decoding, e.g. Viterbi, Fano, ZJ algorithms
• CPC Class Codes: H04L 1/0059 : Convolutional codes
• CPC Class Codes: H04L 2027/003 : at baseband only
• CPC Class Codes: H04L 2027/0053 : Closed loops
• CPC Class Codes: H04L 25/0212 : of impulse response
• CPC Class Codes: H04L 27/206 : using a pair of orthogonal carriers, e.g. quadrature carriers
• CPC Class Codes: H04L 27/2332 : using a non-coherent carrier
• CPC Class Codes: H04L 5/1446 : of transmission speed
• CPC Class Codes: H04N 1/00912 : Arrangements for controlling a still picture apparatus or components thereof not otherwise provided for
• CPC Class Codes: H04N 1/3333 : during transmission, input or output of the picture signal; within a single document or page
• CPC Class Codes: H04N 2201/3335 : Speed or rate
• CPC Class Codes: H04W 52/04 : TPC
• CPC Class Codes: H04W 52/08 : Closed loop power control
• CPC Class Codes: H04W 52/143 : Downlink power control
• CPC Class Codes: H04W 52/146 : Uplink power control
• CPC Class Codes: H04W 52/24 : using SIR [Signal to Interference Ratio] or other wireless path parameters
• CPC Class Codes: H04W 52/241 : taking into account channel quality metrics, e.g. SIR, SNR, CIR, Eb/lo
• CPC Class Codes: H04W 52/245 : taking into account received signal strength
• CPC Class Codes: H04W 52/247 : where the output power of a terminal is based on a path parameter sent by another terminal
• CPC Class Codes: H04W 52/26 : using transmission rate or quality of service QoS [Quality of Service]
• CPC Class Codes: H04W 52/262 : taking into account adaptive modulation and coding [AMC] scheme AMC per se H04L1/0001
• CPC Class Codes: H04W 52/322 : Power control of broadcast channels
• CPC Class Codes: H04W 52/325 : Power control of control or pilot channels
• CPC Class Codes: H04W 52/343 : taking into account loading or congestion level
• CPC Class Codes: H04W 52/346 : distributing total power among users or channels
• CPC Class Codes: H04W 52/36 : with a discrete range or set of values, e.g. step size, ramping or offsets
• CPC Class Codes: H04W 52/367 : Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 52/44 : in connection with interruption of transmission
• CPC Class Codes: H04W 52/50 : at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 52/52 : using AGC [Automatic Gain Control] circuits or amplifiers
• CPC Class Codes: H04W 52/54 : Signalisation aspects of the TPC commands, e.g. frame structure
• CPC Class Codes: H04W 52/60 : using different transmission rates for TPC commands
• CPC Class Codes: Y02D 10/00 : Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A method and system for rapidly acquiring a spreading code, used in a code division multiple access (CDMA) system. A first long code and a second long code, with each long code having a length of N chips, are generated. The first long code is different from the second long code. The first long code and the second long code are transmitted at a first phase angle and at a second phase angle, respectively, on a carrier signal, over a communications channel using radio waves. The first long code and the second long code may be transmitted at an in-phase (I) angle and at a quadrature-phase (Q) angle, respectively, on the carrier signal. From the communications channel, an I-phase acquisition circuit and a Q-phase acquisition circuit may acquire, in parallel, the first long code and the second long code from the I-phase angle and the Q-phase angle, respectively, of the carrier signal by searching, in parallel, N/2 chips, the first long code and the second long code.

Claims

1. A method of rapidly acquiring a spreading code, used in a code division multiple access (CDMA) system, the method comprising the steps of:

(a) generating a first long code and a second long code from a plurality of short codes, wherein each of the long codes has a length of N chips and each of the short codes is different and has a length less than N chips, and each of the first and second long codes include a respective one of the plurality of short codes embedded therein,

(b) transmitting, over a communications channel using radio waves, the first long code and the second long code, at a first phase angle and at a second phase angle, respectively, on a carrier signal, with the first phase angle different from the second phase angle; and

(c) acquiring, from the communications channel, using two phase-acquisition circuits in parallel, the first long code and the second long code from the first phase angle and the second phase angle, respectively, by searching, in parallel, N/2 chips, the first long code and the second long code.

2. The method of claim 1, wherein step (b) further includes transmitting the first long code and the second long code, at an in-phase (I) angle and at a quadrature (Q) angle, respectively, on the carrier signal, with the I angle ninety degrees out of phase with the Q angle.

3. The method of claim 2, wherein step (c) further includes acquiring, from the communications channel, using an I-channel phase-acquisition circuit and a Q-channel phase-acquisition circuit in parallel, the first long code and the second long code from the I angle and the Q angle, respectively, of the carrier signal by searching, in parallel, N/2 chips, of the first long code and the second long code.

4. The method of claim 1, wherein step (b) further includes transmitting the first long code and the second long code, at an in-phase (I) angle and at a quadrature (Q) angle, respectively.

5. The method of claim 4, wherein step (c) further includes acquiring, from the communications channel, using an I-channel phase-acquisition circuit and a Q-channel phase-acquisition circuit in parallel, the first long code and the second long code from the I angle and the Q angle, respectively, of the carrier signal by searching, in parallel, N/2 chips, of the first long code and the second long code.

6. The method of claim 1 wherein step (c) further includes acquiring, from the communications channel, using the two phase-acquisition circuits in parallel, the embedded short codes, from the first phase angle and the second phase angle, respectively, by searching, in parallel, N/2 chips, of each of the embedded short codes.

7. A method of rapidly acquiring a spreading code, used in a code division multiple access (CDMA) system, the method comprising the steps of:

(a) generating a plurality of P long codes from a plurality of short codes, wherein each of the P long codes has a length of N chips and each of the short codes is different and has a length less than N chips, and each of the P codes include a respective one of the plurality of short codes embedded therein, where P is a number of long codes in the plurality of long codes;

(b) transmitting, over a communications channel using radio waves, the plurality of long codes at a plurality of phase angles, respectively, on a carrier signal, with each phase angle in the plurality of phase angles different from other phase angles in the plurality of phase angles; and

(c) acquiring, from the communications channel, using phase-acquisition means, the plurality of long codes, respectively, by searching, in parallel, N/P chips, of each long code of the plurality of long codes.

8. The method of claim 7 wherein step (c) further includes acquiring, from the communications channel, using the phase-acquisition means, the plurality of long codes from the plurality of phase angles, respectively.

9. The method of claim 7 wherein step (b) further includes transmitting the plurality of long codes at the plurality of phase angles, respectively, on the carrier signal, with each phase angle in the plurality of phase angles representing an M-ary phase scheme.

10. The method of claim 7 wherein step (c) further includes acquiring, from the communications channel, using the phase-acquisition means, the plurality of long codes, respectively, of the carrier signal by searching, in parallel, N/P chips, of a first long code and a second long code.

11. The method of claim 7 wherein step (c) further includes acquiring, from the communications channel, using the phase-acquisition means, the embedded short codes, from a first phase angle and a second phase angle, respectively, by searching, in parallel, N/P chips, of the embedded short codes.

12. A code division multiple access (CDMA) system for rapidly acquiring a spreading code, the system comprising:

(a) generator means for generating a first long code and a second long code from a plurality of short codes, wherein, each of the long codes has a length of N chips and each of the short codes is different and has a length less than N chips, and each of the first and second long codes include a respective one of the plurality of short codes embedded therein;

(b) transmitter means for transmitting, over a communications channel using radio waves, the first long code and the second long code, at a first phase angle and at a second phase angle, respectively, on a carrier signal, with the first phase angle different from the second phase angle; and

(c) acquisition means for acquiring, from the communications channel, using two phase-acquisition circuits in parallel, the first long code and the second long code from the first phase angle and the second phase angle, respectively, by searching, in parallel, N/2 chips, of the first long code and the second long code.

13. The system of claim 12, wherein said transmitter means further includes means for transmitting the first long code and the second long code, at an in-phase (I) angle and at a quadrature (Q) angle, respectively, on the carrier signal, with the I angle ninety degrees out of phase with the Q angle.

14. The system of claim 13, wherein said acquisition means further includes means for acquiring, from the communications channel, using an I-channel phase-acquisition circuit and a Q-channel phase-acquisition circuit in parallel, the first long code and the second long code from the I angle and the Q angle, respectively, of the carrier signal by searching, in parallel, N/2 chips, of the first long code and the second long code.

15. The system of claim 12, wherein said transmitter means further includes means for transmitting the first long code and the second long code, at an in-phase (I) angle and at a quadrature (Q) angle, respectively.

16. The system of claim 15, wherein said acquisition means further includes means for acquiring, from the communications channel, using an I-channel phase-acquisition circuit and a Q-channel phase-acquisition circuit in parallel, the first long code and the second long code from the I angle and the Q angle, respectively, of the carrier signal by searching, in parallel, N/2 chips, of the first long code and the second long code.

17. The system of claim 12 wherein said acquisition means further includes means for acquiring, from the communications channel, using the two phase-acquisition circuits in parallel, the embedded short codes, from the first phase angle and the second phase angle, respectively, by searching, in parallel, N/2 chips, of each of the embedded short codes.

18. A code division multiple access (CDMA) system for rapidly acquiring a spreading code, the system comprising:

(a) generator means for generating a plurality of P long codes from a plurality of short codes, wherein each of the P long codes has a length of N chips and each of the short codes is different and has a length less than N chips, and each of the P long codes include a respective one of the plurality of short codes embedded therein, where P is a number of long codes in the plurality of long codes;

(b) transmitter means for transmitting, over a communications channel using radio waves, the plurality of long codes at a plurality of phase angles, respectively, on a carrier signal, with each phase angle in the plurality of phase angles different from other phase angles in the plurality of phase angles; and

(c) at least one phase-acquisition means for acquiring, from the communications channel, the plurality of long codes, respectively, by searching, in parallel, N/P chips, of each long code of the plurality of long codes.

19. The system of claim 18 wherein said phase-acquisition means further includes means for acquiring, from the communications channel, the plurality of long codes from the plurality of phase angles, respectively.

20. The system of claim 18 wherein said transmitter means further includes means for transmitting the plurality of long codes at the plurality of phase angles, respectively, on the carrier signal, with each phase angle in the plurality of phase angles representing an M-ary phase scheme.

21. The system of claim 18 wherein said phase-acquisition means further includes means for acquiring, from the communications channel, the plurality of long codes, respectively, of the carrier signal by searching, in parallel, N/P chips, of a first long code and a second long code.

22. The system of claim 18 wherein said phase-acquisition means further includes means for acquiring, from the communications channel, the embedded short codes, from a first phase angle and a second phase angle, respectively, by searching, in parallel, N/P chips, of the embedded short codes.

23. A code division multiple access (CDMA) system for rapidly acquiring a spreading code, the system comprising:

a code generator for generating a first long code and a second long code from a plurality of short codes, wherein each of the long codes has a length of N chips and each of the short codes is different and has a length less than N chips, and each of the first and second long codes include a respective one of the plurality of short codes embedded therein;

(b) a transmitter, coupled to said code generator, for transmitting, over a communications channel using radio waves, the first long code and the second long code, at a first phase angle and at a second phase angle, respectively, on a carrier signal, with the first phase angle different from the second phase angle; and

(c) an acquisition circuit, coupled to the communications channel, for acquiring, from the communications channel, using two phase-acquisition circuits in parallel, the first long code and the second long code from the first phase angle and the second phase angle, respectively, by searching, in parallel, N/2 chips, of the first long code and the second long code.

24. The system of claim 23 wherein said transmitter further includes means for transmitting the first long code and the second long code, at an in-phase (I) angle and at a quadrature (Q) angle, respectively, on the carrier signal, with the I angle ninety degrees out of phase with the Q angle.

25. The system of claim 24 wherein said acquisition circuit further includes means for acquiring, from the communications channel, using an I-channel phase-acquisition circuit and a Q-channel phase-acquisition circuit in parallel, the first long code and the second long code from the I angle and the Q angle, respectively, of the carrier signal by searching, in parallel, N/2 chips, of the first long code and the second long code.

26. The system of claim 23 wherein said transmitter further includes means for transmitting the first long code and the second long code, at an in-phase (I) angle and at a quadrature (Q) angle, respectively.

27. The system of claim 26 wherein said acquisition circuit further includes means for acquiring, from the communications channel, using an I channel phase-acquisition circuit and a Q-channel phase-acquisition circuit in parallel, the first long code and the second long code from the I angle and the Q angle, respectively, of the carrier signal by searching, in parallel, N/2 chips, of the first long code and the second long code.

28. The system of claim 23 wherein said acquisition circuit further includes means for acquiring, from the communications channel, using the two phase-acquisition circuits in parallel, the embedded short codes from the first phase angle and the second phase angle, respectively, by searching, in parallel, N/2 chips, of each of the embedded short codes.

29. A code division multiple access (CDMA) system for rapidly acquiring a spreading code, the system comprising:

(a) a code generator for generating a plurality of P long codes from a plurality of short codes, wherein each of the P long codes has a length of N chips and each of the short codes is different and has a length less than N chips, and each of the P long codes include a respective one of the plurality of short codes embedded therein, where P is a number of long codes in the plurality of long codes;

(b) a transmitter, coupled to said code generator, for transmitting, over a communications channel using radio waves, the plurality of long codes at a plurality of phase angles, respectively, on a carrier signal, with each phase angle in the plurality of phase angles different from other phase angles in the plurality of phase angles; and

(c) at least one phase-acquisition circuit, coupled to the communications channel, for acquiring, from the communications channel, the plurality of long codes, respectively, by searching, in parallel, N/P chips, of each long code of the plurality of long codes.

30. The system of claim 29 wherein said phase-acquisition circuit further includes means for acquiring, from the communications channel, the plurality of long codes from the plurality of phase angles, respectively.

31. The system of claim 29 wherein said transmitter further includes means for transmitting the plurality of long codes at the plurality of phase angles, respectively, on the carrier signal, with each phase angle in the plurality of phase angles representing an M-ary phase scheme.

32. The system of claim 29 wherein said phase-acquisition circuit further includes means for acquiring, from the communications channel, the plurality of long codes, respectively, of the carrier signal by searching, in parallel, N/P chips, of a first long code and a second long code.

33. The system of claim 29 wherein said phase-acquisition circuit further includes means for acquiring, from the communications channel, the embedded short codes from a first phase angle and a second phase angle, respectively, by searching, in parallel, N/P chips, of the embedded short codes.