Dynamic sectorization in a spread spectrum communication system

• US 7,653,149 B2
• Filed: 12/17/2001
• Issued: 01/26/2010
• Est. Priority Date: 02/14/1994
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Thompson, James H., Strich, W. Eli
• Primary Examiner(s): Torres; Juan A
• Application Number:
  US10/021,865
• Publication Number:
  US 20020054580A1
• Time in Patent Office: 2,962 Days
• Field of Search: 375/347, 375/130, 375/147, 375/310, 370/320, 370/206
• US Class Current: 375/310
• CPC Class Codes: H04W 16/06 Hybrid resource partitioning, e.g. channel borrowing
• CPC Class Codes: H04W 16/24 Cell structures
• CPC Class Codes: H04W 16/28 using beam steering

Abstract

A system and method for dynamically varying traffic channel sectorization within a spread spectrum communication system is disclosed herein. In a preferred implementation the system is operative to convey information to at least one specified user in a spread spectrum communication system and includes multiple antennas, each having an associated coverage area, and each coupled to an antenna driver. The antenna drivers each include a delay element and an input summation node. A switching transmission network is disposed to selectively transmit via antennas. Selective transmission of signals results in variation in size of a given user sector. In another aspect, the system may be configured to selectively receive, and coherently combine, signals from different coverage areas.

Claims

1. A method for dynamically varying traffic channel sectorization within a spread spectrum communication system comprising:

receiving a first PN-modulated signal from a first sector;

receiving a second PN-modulated signal from a second sector adjacent to said first sector;

introducing a delay between a pair of PN-modulated signals comprising the first PN-modulated signal and the second PN-modulated signal projected to adjacent coverage areas, whereby said pair of PN-modulated signals are decorrelated; and

summing a delayed second PN-modulated signal and the first PN-modulated signal.

2. The method as in claim 1, farther comprising:

splitting the first PN-modulated signal into multiple parts; and

splitting the second PN-modulated signal into multiple parts.

3. The method as in claim 2, wherein summing further comprises:

summing one of the multiple parts of the first PN-modulated signal with one of the multiple parts of the second PN-modulated signal to form a first summation signal.

4. The method as in claim 3, wherein summing further comprises:

summing a second one of the multiple parts of the first PN-modulated signal with a second one of the multiple parts of the second PN-modulated signal to form a second summation signal.

5. The method as in claim 4, further comprising:

generating an In-phase component and a Quadrature component of the first summation signal; and

generating an In-phase component and a Quadrature component of the second summation signal.

6. The method as in claim 5, further comprising:

generating a despreading code;

despreading the In-phase component and the Quadrature component of the first summation signal with the despreading code;

offsetting the despreading code by a first phase delay to form a delayed despreading code; and

despreading the In-phase component and the Quadrature component of the second summation signal with the delayed despreading code.

7. The method of claim 1, further comprising:

varying the size of a set of user sectors between successive system operating periods, comprising;

introducing a delay between said pair of PN-modulated signals projected to adjacent coverage areas within a given user sector;

discriminating between said pair of PN-modulated signals;

time-aligning said pair of PN-modulated signals; and

despreading said pair of PN-modulated signals using a locally-generated replica of a PN long code.

8. The method according to claim 1, wherein said delay has a duration slightly longer than a period of a chip of a PN long code used to decorrelate said pair of PN-modulated signals.

9. A wireless infrastructure for dynamically varying traffic channel sectorization within a spread spectrum communication system, comprising:

means for receiving a first PN-modulated signal from a first sector;

means for receiving a second PN-modulated signal from a second sector adjacent to said first sector;

means for introducing a delay between a pair of PN-modulated signals comprising the first PN-modulated signal and the second PN-modulated signal projected to adjacent coverage areas, whereby said pair of PN-modulated signals are decorrelated; and

means for summing a delayed second PN-modulated signal and the first PN-modulated signal.

10. The wireless infrastructure of claim 9, further comprising:

means for splitting the first PN-modulated signal into multiple parts; and

means for splitting the second PN-modulated signal into multiple parts.

11. The wireless infrastructure of claim 10, wherein the means for summing further sums one of multiple parts of the first PN-modulated signal with one of the multiple parts of the second PN-modulated signal to form a first summation signal.

12. The wireless infrastructure of claim 11, wherein the means for summing further sums a second one of the multiple parts of the first PN-modulated signal with a second one of the multiple parts of the second PN-modulated signal to form a second summation signal.

13. The wireless infrastructure of claim 12, further comprising:

means for generating an In-phase component and a Quadrature component of the first summation signal; and

means for generating an In-phase component and a Quadrature component of the second summation signal.

14. The wireless infrastructure of claim 13, further comprising:

means for generating a despreading code;

means for despreading the In-phase component and the Quadrature component of the first summation signal with the despreading code;

means for offsetting the despreading code by a first phase delay to form a delayed despreading code; and

means for despreading the In-phase component and the Quadrature component of the second summation signal with the delayed despreading code.

15. The wireless infrastructure of claim 9, further comprising:

means for varying the size of a set of user sectors between successive system operating periods for introducing a delay between said pair of PN-modulated signals projected to adjacent coverage areas within a given user sector;

means for discriminating between said pair of PN-modulated signals;

means for time-aligning said pair of PN-modulated signals; and

means for despreading said pair of PN-modulated signals using a locally-generated replica of a PN long code.

16. The wireless infrastructure of claim 9, wherein said delay has a duration slightly longer than a period of a chip of a PN long code used to decorrelate said pair of PN-modulated signals.

17. A wireless infrastructure to provide dynamic user sectorization by decorrelating signals received from adjacent coverage areas, comprising:

a plurality of antenna elements, each antenna element associated with a coverage area of a wireless communication system;

a plurality of receive amplifiers, comprising delay elements operably connected to said plurality of antennas, wherein a decorrelating delay is introduced between said signals provided to said adjacent coverage areas, each receive amplifier coupled to one of the plurality of antenna elements;

a switch matrix coupled to the plurality of receive amplifiers; and

a plurality of summation networks coupled to the switch matrix and adapted to receive information from each of the plurality of receive amplifiers, wherein the plurality of receivers are operably connected to the plurality of summation networks.

18. A base station receiver network configured to provide dynamic user sectorization by decorrelating delays between received signals from adjacent coverage areas, comprising:

a plurality of antennas;

a first plurality of receive amplifiers comprising a plurality of delay elements operably connected to said plurality of antennas, wherein said decorrelating delays are introduced between said received signals from said adjacent coverage areas;

at least one switch matrix operably connected to said first plurality of receive amplifiers, whereby information from user sectors are routed to users within said adjacent coverage areas;

a plurality of summation networks operably connected to said at least one switch matrix;

a plurality of receivers operably connected to said plurality of summation networks, whereby said received signals are downconverted and digitized into composite I and Q components;

a PN long code generator for providing a PN long code to said plurality of receivers; and

a plurality of phase delay elements operably connected to said plurality of receivers for offsetting said PN long code by a predetermined margin.

19. The base station receiver network according to claim 18, further comprising a second plurality of amplifiers operably connected between said plurality of receivers and said plurality of summation networks.

20. The base station receiver network according to claim 18, wherein said plurality of receivers comprises at least one RAKE receiver.

21. The base station receiver network according to claim 18, wherein at least one of the plurality of delay elements is a surface acoustic wave filter.

22. The base station receiver network according to claim 18, wherein at least one of said decorrelating delays is equivalent to 768 chips.

23. The base station receiver network according to claim 20, wherein said at least one RAKE receiver comprises a plurality of demodulators.

24. A computer-readable medium including program code stored thereon comprising:

program code for receiving a first PN-modulated signal from a first sector;

program code for receiving a second PN-modulated signal from a second sector adjacent to said first sector;

program code for introducing a delay between a pair of PN-modulated signals comprising the first PN-modulated signal and the second PN-modulated signal projected to adjacent coverage areas, whereby said pair of PN-modulated signals are decorrelated; and

program code for summing a delayed second PN-modulated signal and the first PN-modulated signal.

25. The computer-readable medium of claim 24, further comprising:

program code for splitting the first PN-modulated signal into multiple parts; and

program code for splitting the second PN-modulated signal into multiple parts.

26. The computer-readable medium of claim 25, wherein the program code for summing comprises:

program code for summing one of the multiple parts of the first PN-modulated signal with one of the multiple parts of the second PN-modulated signal to form a first summation signal.

27. The computer-readable medium of claim 26, wherein the program code for summing further comprises:

program code for summing a second one of the multiple parts of the first PN-modulated signal with a second one of the multiple parts of the second PN-modulated signal to form a second summation signal.

28. The computer-readable medium of claim 27, further comprising:

program code for generating an In-phase component and a Quadrature component of the first summation signal; and

program code for generating an In-phase component and a Quadrature component of the second summation signal.

29. The computer-readable medium of claim 28, further comprising:

program code for generating a despreading code;

program code for despreading the In-phase component and the Quadrature component of the first summation signal with the despreading code;

program code for offsetting the despreading code by a first phase delay to form a delayed despreading code; and

program code for despreading the In-phase component and the Quadrature component of the second summation signal with the delayed despreading code.

30. The computer-readable medium of claim 24, further comprising:

program code for varying the size of a set of user sectors between successive system operating periods, wherein the program code for varying comprises;

program code for introducing a delay between said pair of PN-modulated signals projected to adjacent coverage areas within a given user sector;

program code for discriminating between said pair of PN-modulated signals;

program code for time-aligning said pair of PN-modulated signals; and

program code for despreading said pair of PN-modulated signals using a locally-generated replica of a PN long code.

31. The computer-readable medium of claim 24, wherein said delay has a duration slightly longer than a period of a chip of a PN long code used to decorrelate said pair of PN-modulated signals.

32. A base station receiver for dynamically varying traffic channel sectorization within a spread spectrum communication system comprising:

at least one antenna for receiving a first PN-modulated signal from a first sector and for receiving a second PN-modulated signal from a second sector adjacent to said first sector;

a delay element coupled to the at least one antenna for introducing a delay between a pair of PN-modulated signals comprising the first PN-modulated signal and the second PN-modulated signal projected to adjacent coverage areas, whereby said pair of PN-modulated signals are decorrelated; and

a summation network coupled to the delay element for summing a delayed second PN-modulated signal and the first PN-modulated signal.

33. The base station receiver of claim 32, farther comprising:

at least one splitter coupled to the delay element for splitting the first PN-modulated signal into multiple parts, and for splitting the second PN-modulated signal into multiple parts.

34. The base station receiver of claim 33, wherein the summation network further sums one of the multiple parts of the first PN-modulated signal with one of the multiple parts of the second PN-modulated signal to form a first summation signal.

35. The base station receiver of claim 34, wherein the summation network farther sums a second one of the multiple parts of the first PN-modulated signal with a second one of the multiple parts of the second PN-modulated signal to form a second summation signal.

36. The base station receiver of claim 35, farther comprising:

at least one diversity receiver for generating an In-phase component and a Quadrature component of the first summation signal, and for generating an In-phase component and a Quadrature component of the second summation signal.

37. The base station receiver of claim 36, further comprising a PN code generator for generating a despreading code;

and wherein the at least one diversity receiver further despreads the In-phase component and the Quadrature component of the first summation signal with the despreading code, offsets the despreading code by a first phase delay to form a delayed despreading code, and despreads the In-phase component and the Quadrature component of the second summation signal with the delayed despreading code.

38. The base station receiver of claim 32, wherein the at least one antenna varies the size of a set of user sectors between successive system operating periods;

and wherein the delay element further introduces a delay between said pair of PN-modulated signals projected to adjacent coverage areas within a given user sector; and

further comprising a PN code generator for generating a PN long code to discriminate between said pair of PN-modulated signals, for time-aligning said pair of PN-modulated signals, and for despreading said pair of PN-modulated signals using a locally-generated replica of the PN long code.

39. The base station receiver of claim 32, wherein said delay has a duration slightly longer than a period of a chip of a PN long code used to decorrelate said pair of PN-modulated signals.