Broadband CDMA overlay system and method

• US 6,389,002 B1
• Filed: 09/21/1999
• Issued: 05/14/2002
• Est. Priority Date: 12/05/1990
• Status: Expired due to Fees

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Schilling, Donald L.
• Primary Examiner(s): TON, DANG T
• Application Number:
  US09/400,715
• Time in Patent Office: 966 Days
• Field of Search: 370/310, 370/312, 370/313, 370/314, 370/320, 370/321, 370/329, 370/335, 370/336, 370/337, 370/342, 370/346, 370/347, 370/350, 375/131, 375/130, 375/145, 375/137, 455/38.3, 455/38.1, 455/422, 455/420, 380/34, 380/48, 379/219, 379/230, 379/231
• US Class Current: 370/342
• CPC Class Codes: G01S 13/82 wherein continuous-type signals are transmitted
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04B 1/71 the interference being narrowband interference
• CPC Class Codes: H04B 1/7101 with estimation filters
• CPC Class Codes: H04B 1/7102 with transform to frequency domain
• CPC Class Codes: H04B 7/18547 for geolocalisation of a station position fixing by direction or distance determination G01S5/00
• CPC Class Codes: H04B 7/216 Code division or spread-spectrum multiple access [CDMA, SSMA]
• 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 7/2631 for broadband transmission
• CPC Class Codes: H04J 13/00 Code division multiplex systems for frequency hopping H04B1/713
• CPC Class Codes: H04W 4/18 Information format or content conversion, e.g. adaptation by the network of the transmitted or received information for the purpose of wireless delivery to users or terminals
• 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 84/042 Public Land Mobile systems, e.g. cellular systems
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: H04W 92/18 between terminal devices

Abstract

A spread-spectrum CDMA communications system for communicating data between a plurality of users to a plurality of spread-spectrum units. The spread-spectrum communications system is located within a same geographical region as occupied by an existing FDMA, proposed TDMA or any other mobile-cellular system. The spread-spectrum CDMA communications system includes a plurality of spread-spectrum-base stations and a plurality of spread-spectrum units. A spread-spectrum-base station has a comb filter for notch filtering predetermined channels of the mobile-cellular system, a device for converting the format of the data into a form for communicating over radio waves, a spread-spectrum modulator for spread-spectrum processing the data, and a transmitter for transmitting the spread-spectrum-processed converted data from the spread-spectrum-base station to a spread-spectrum unit. The spread-spectrum-base station also has an antenna, and spread-spectrum detectors for recovering data communicated from the spread-spectrum units. A spread-spectrum unit has an antenna, and a detector, including a spread-spectrum demodulator, coupled to the antenna for recovering data communicated from the spread-spectrum-base station, and the spread-spectrum unit has a spread-spectrum modulator, a transmitter, and a device for converting the format of the data for communicating over radio waves.

Claims

1. A method of non-interferingly overlaying spread-spectrum code division multiple access (CDMA) signals within a wide bandwidth over an existing cellular communication system, the existing system having a plurality of base stations, each said base station having an operating area divided into a plurality of sectors, each said base station'"'"'s sector assigned predetermined frequency bandwidths within the wide CDMA bandwidth for use in communicating data between that sector'"'"'s base station and non-CDMA cellular users within that sector, the method comprising:

generating a spread-spectrum data signal having a pseudo random chip code sequence for a selected spread-spectrum unit within one of said existing base station'"'"'s operating area for transmission over the wide CDMA bandwidth;

determining the frequency bandwidths assigned to said sector of said one base station where said selected unit is located and the frequency bandwidths assigned to said sectors of others of said existing base stations contiguous with said selected unit'"'"'s sector;

notch filtering said spread-spectrum data signal at the determined frequency bandwidths;

transmitting said notch filtered spread-spectrum data signal to said selected unit over the wide bandwidth; and

at said selected unit, receiving said notch filtered spread-spectrum data signal.

2. The method of claim 1 wherein each of said base station'"'"'s operating area is divided into six sectors and said contiguous sectors of the other existing base stations is two sectors.

3. The method of claim 1 wherein each of the base station'"'"'s operating area is divided into three sectors and said contiguous sectors of the other existing base stations is two sectors.

4. The method of claim 1 wherein said non-CDMA cellular users are time division multiple access users.

5. The method of claim 1 wherein said non-CDMA cellular users are frequency division multiple access users.

6. The method of claim 1 wherein said wide CDMA bandwidth is 10 MHz and each of the frequency bandwidths are 30 KHz.

7. The method of claim 1 wherein the step of receiving said notch filtered spread-spectrum data signal includes the steps of:

storing a local pseudo random chip code sequence;

comparing the local chip code to said received spread-spectrum data signal; and

recovering data sent from said base station to said selected unit.

8. A spread-spectrum code division multiple access (CDMA) communication system for non-interferingly overlaying spread-spectrum CDMA signals within a wide bandwidth over an existing cellular communication system, the existing system having a plurality of base stations, each said base station having an operating area divided into a plurality of sectors, each said base station'"'"'s sector assigned predetermined frequency bandwidths within the wide CDMA bandwidth for use in communicating data between that sector'"'"'s base station and non-CDMA cellular users within that sector, the system comprising:

one of said plurality of base stations comprising;

means for generating a spread-spectrum data signal having a pseudo random chip code sequence for a selected spread-spectrum unit within said one base station'"'"'s operating area for transmission over the wide CDMA bandwidth;

means for determining the frequency bandwidths assigned to said sector where said selected unit is located and the frequency bandwidths assigned to said sectors of others of said existing base stations contiguous with said selected unit'"'"'s sector;

means for notch filtering said spread-spectrum data signal at the determined frequency bandwidths; and

means for transmitting said notch filtered spread-spectrum data signal to said selected unit over the wide bandwidth; and

said selected unit comprising;

means for receiving said notch filtered spread-spectrum data signal.

9. The system of claim 8 wherein said means for receiving said notch filtered spread-spectrum data signal comprises:

means for demodulating, said received spread-spectrum data signal; and

means for converting data from the demodulated spread-spectrum data signal into a form for output to a user.

10. The system of claim 9 wherein said means for demodulating includes means for processing said received spread-spectrum data signal with a selected pseudo random chip code sequence associated with said selected unit.

11. The system of claim 9 wherein said demodulating means includes a memory for storing a local pseudo random chip code sequence for comparison to the received spread-spectrum data signal to recover data sent from said one base station.

12. The system of claim 9 wherein said demodulating means comprises a coherent detector.

13. The system of claim 9 wherein said demodulating means comprises a non-coherent detector.

14. The system of claim 8 wherein said receiving means includes a phase-lock loop for synchronizing said selected unit with said received spread-spectrum data signal.

15. The system of claim 8 wherein said receiving means comprises a notch filter for filtering the received spread-spectrum data signal at the determined frequency bandwidths.

16. A transmitter for non-interferingly overlaying spread-spectrum code division multiple access (CDMA) signals within a wide CDMA bandwidth over an existing cellular communication system, the existing system having a plurality of base stations, each said base station having an operating area divided into a plurality of sectors, each said base station'"'"'s sector assigned predetermined frequency bandwidths within the wide CDMA bandwidth for use in communicating data between that sector'"'"'s base station and non-CDMA cellular users within that sector, the transmitter comprising:

means for generating a spread-spectrum data signal having a pseudo random chip code sequence for a selected spread-spectrum unit within one of said existing base station'"'"'s operating area for transmission over the wide CDMA bandwidth;

means for determining the frequency bandwidths assigned to said sector of said one base station where said selected unit is located and the frequency bandwidths assigned to said sectors of others of said existing base stations contiguous with said selected unit'"'"'s sector;

means for notch filtering said spread-spectrum data signal at the determined frequency bandwidths; and

means for transmitting said notch filtered spread-spectrum data signal to said selected unit over the wide bandwidth.

17. The transmitter of claim 16 wherein said notch filtering means is a comb filter.

18. The transmitter of claim 16 wherein said generating means comprises an EXCLUSIVE-OR gate for processing data to be sent to said selected unit with the pseudo random chip code sequence associated with said selected unit.

19. The transmitter of claim 18 wherein said generating means further comprises a modulator operatively coupled to the EXCLUSIVE-OR gate for converting data to be sent to said selected unit into a format suitable for transmission over radio waves.

20. The transmitter of claim 19 wherein said generating means further comprises a transmitter operatively coupled to the EXCLUSIVE-OR gate for modulating said processed data to radio frequency.