Time division duplex repeater for use in a CDMA system

• US 6,108,364 A
• Filed: 08/31/1995
• Issued: 08/22/2000
• Est. Priority Date: 08/31/1995
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Dean, Richard F., Weaver, Lindsay A. Jr., Antonio, Franklin P.
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): Roundtree, Joseph
• Application Number:
  US08/522,469
• Time in Patent Office: 1,818 Days
• Field of Search: 370/280-282, 370/307, 375/200, 375/202, 375/206, 375/208, 375/211, 455/11.1, 455/18, 455/436-437, 455/442, 455/454
• US Class Current: 375/130
• CPC Class Codes: H04B 7/15535 Control of relay amplifier gain amplifier gain control in general H03G3/00; gain control reducing self - or loop interference H04B7/15578
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• CPC Class Codes: H04B 7/2618 using hybrid code-time division multiple access [CDMA-TDMA]
• CPC Class Codes: H04W 16/26 Cell enhancers or enhancement, e.g. for tunnels, building shadow
• CPC Class Codes: H04W 52/40 during macro-diversity or soft handoff
• CPC Class Codes: H04W 52/46 in multi hop networks, e.g. wireless relay networks

Abstract

A method and apparatus for time division duplex (TDD) repeating a spread spectrum signal, where spread spectrum signal is comprised of a series of code symbol modulated with a pseudonoise (PN) sequence. The TDD repeater receives intermittently the spread spectrum signal at a location remote from a source supplying the spread spectrum signal. The TDD repeater amplifies and delays the received spread spectrum signal by a predetermined amount. The TDD repeater transmits intermittently the delayed amplified received spread spectrum signal such that the TDD is not receiving the spread spectrum signal when it is transmitting the signal energy.

Claims

1. A method of amplifying a spread spectrum signal at a repeater site, said spread spectrum signal comprised of a series of code symbols, said method comprising the steps of:

receiving during a first interval said spread spectrum signal;

amplifying said received spread spectrum signal;

delaying with a delay circuit said amplified received spread spectrum signal by a predetermined amount;

transmitting from an antenna during a second interval said delayed amplified received spread spectrum signal, said delay circuit and said antenna being electrically connected and located within said repeater site; and

wherein said step of receiving and said step of transmitting are mutually exclusive events.

2. The method of amplifying a spread spectrum signal of claim 1 wherein each symbol of said series of code symbols is one symbol duration in length and wherein said predetermined amount of delay is smaller than said symbol duration.

3. The method of amplifying a spread spectrum signal of claim 1 wherein said steps of receiving and transmitting are periodic with a period equal to approximately twice said predetermined amount of delay.

4. The method of amplifying a spread spectrum signal of claim 1 wherein said step of delaying is accomplished using a standing acoustic wave (SAW) filter.

5. The method of amplifying a spread spectrum signal of claim 1 wherein said steps of receiving, amplifying, delaying, and transmitting are performed at a first location remote from a source supplying said spread spectrum signal, further comprising the steps of:

receiving during a third interval at a second location said transmitted spread spectrum signal;

amplifying at said second location said received spread spectrum signal;

delaying at said second location said amplified received spread spectrum signal by a second predetermined amount; and

transmitting at said second location during a fourth interval said delayed amplified received spread spectrum signal;

wherein said step of receiving and said step of transmitting at said second location are mutually exclusive events.

6. The method of amplifying a spread spectrum signal of claim 5 wherein said steps of receiving and transmitting at said second location are periodic with a period equal to approximately twice said second predetermined amount of delay and wherein said second predetermined amount of delay is at least twice as long as said predetermined amount of delay.

7. The method of amplifying a spread spectrum signal of claim 5 wherein said steps of receiving and transmitting at said second location are periodic with a period equal to approximately twice said second predetermined amount of delay and wherein said second predetermined amount of delay is less than half as long as said predetermined amount of delay.

8. The method of amplifying a spread spectrum signal of claim 5 wherein said step of delaying at said second location is performed by passing said amplified received spread spectrum signal through a standing acoustic wave (SAW) filter tuned to a center frequency of said spread spectrum signal.

9. The method of amplifying a spread spectrum signal of claim 1 further comprising the steps of:

receiving during a third interval a second spread spectrum signal;

amplifying said second received spread spectrum signal;

delaying said second amplified received spread spectrum signal by a second predetermined amount; and

transmitting during a fourth interval said second delayed amplified received spread spectrum signal.

10. The method of amplifying a spread spectrum signal of claim 9 wherein said first interval and said third interval overlap in time.

11. The method of amplifying a spread spectrum signal of claim 9 wherein said first interval and said third interval correspond to the same time interval.

12. The method of amplifying a spread spectrum signal of claim 9 wherein said first interval and said fourth interval overlap in time.

13. The method of amplifying a spread spectrum signal of claim 9 wherein said first interval and said fourth interval correspond to the same time interval.

14. The method of amplifying a spread spectrum signal of claim 9 wherein said second predetermined amount is the same as said predetermined amount.

15. The method of amplifying a spread spectrum signal of claim 9 wherein said second predetermined amount is different from said predetermined amount.

16. The method of amplifying a spread spectrum signal of claim 1 wherein said series of code symbols is modulated with a pseudonoise (PN) sequence.

17. The method of amplifying a spread spectrum signal of claim 1 wherein said series of code symbols is frequency hopped over time.

18. The method of amplifying a spread spectrum signal of claim 1 wherein said step of delaying further comprising the steps of:

converting said amplified received spread spectrum signal to a digital signal;

delaying said converted digital signal using a digital storage device; and

converting said delayed converted digital signal into an analog signal.

19. The method of amplifying a spread spectrum signal of claim 18 wherein said predetermined amount varies over time.

20. An apparatus for amplifying a spread spectrum signal comprising:

means for receiving intermittently said spread spectrum signal;

means for amplifying said received spread spectrum signal;

means for delaying said amplified received spread spectrum signal by a predetermined amount;

means for transmitting intermittently said delayed amplified received spread spectrum signal;

wherein said means for receiving intermittently and said means for transmitting intermittently operate mutually exclusively such that said delayed amplified received spread spectrum signal is transmitted only or said spread spectrum signal is received only;

wherein the apparatus for amplifying said spread spectrum signal further comprises;

means for receiving intermittently a second spread spectrum signal;

means for amplifying said second received spread spectrum signal;

means for delaying said second amplified received spread spectrum signal by a second predetermined amount;

means for transmitting intermittently said second delayed amplified received spread spectrum signal;

wherein the apparatus for amplifying said spread spectrum signal further comprises;

means for detecting a first gain of said intermittently transmitted spread spectrum signal; and

means for adjusting a second gain in said step of amplifying said second received spread spectrum signal based on said first gain.

21. A time division duplex repeater for amplifying a spread spectrum signal comprising:

a first antenna receiving a forward link signal;

an amplifier coupled to said first antenna;

a delay device coupled in series with said first antenna and said amplifier;

a second antenna coupled in series with said first antenna, said amplifier and said delay device for providing a repeated forward link signal; and

an isolation device coupled in series with said amplifier, said first and second antennas, and said delay device for intermittently breaking a connection of said forward link signal to said delay device while said repeated forward link signal is provided by said second antenna.

22. The time division duplex repeater for amplifying a spread spectrum signal of claim 21 wherein said first and second antennas are the same physical structure.

23. The time division duplex repeater for amplifying a spread spectrum signal of claim 21 wherein said first antenna is a directional antenna directed at a source of said forward link signal.

24. The time division duplex repeater for amplifying a spread spectrum signal of claim 21 wherein said first antenna and said second antenna are located some distance apart.

25. The time division duplex repeater for amplifying a spread spectrum signal of claim 21 wherein said delay device is a standing acoustic wave (SAW) filter.

26. The time division duplex repeater for amplifying a spread spectrum signal of claim 21 wherein said delay device comprises:

an analog to digital converter;

a digital storage device coupled to an output of said analog to digital converter; and

a digital to analog converter coupled to an output of said digital storage device.

27. The time division duplex repeater for amplifying a spread spectrum signal of claim 21 further comprising:

a third antenna receiving a reverse link signal;

a reverse link amplifier coupled to said third antenna;

a reverse link delay device coupled in series with said third antenna and said reverse link amplifier;

a fourth antenna coupled in series with said third antenna, said reverse link amplifier and said reverse link delay device for providing a repeated reverse link signal; and

a reverse link isolation device coupled in series with said reverse link amplifier, said third and fourth antennas, and said reverse link delay device for intermittently disrupting a connection of said reverse link signal to said reverse link delay device while said repeated reverse link signal is provided by said fourth antenna.

28. The time division duplex repeater for amplifying a spread spectrum signal of claim 27 wherein said first, second, third and fourth antennas are the same physical structure.

29. The time division duplex repeater for amplifying a spread spectrum signal of claim 27 wherein said third and fourth antennas are the same physical structure.

30. The time division duplex repeater for amplifying a spread spectrum signal of claim 27 wherein said first and third antennas are the same physical structure.

31. The time division duplex repeater for amplifying a spread spectrum signal of claim 27 wherein said first and third antennas are a single directional antenna.

32. The time division duplex repeater for amplifying a spread spectrum signal of claim 21 wherein said spread spectrum signal is modulated with a pseudonoise (PN) sequence.

33. The time division duplex repeater for amplifying a spread spectrum signal of claim 21 wherein said spread spectrum signal is frequency hopped over time.

34. A method of amplifying a spread spectrum signal, said spread spectrum signal comprised of a series of code symbols, said method comprising the steps of:

receiving during a first interval said spread spectrum signal;

amplifying said received spread spectrum signal;

delaying said amplified received spread spectrum signal by a predetermined amount;

transmitting during a second interval said delayed amplified received spread spectrum signal;

wherein said step of receiving and said step of transmitting are mutually exclusive events and wherein the method of amplifying said spread spectrum signal further comprises the steps of;

receiving during a third interval a second spread spectrum signal;

amplifying said second received spread spectrum signal;

delaying said second amplified received spread spectrum signal by a second predetermined amount;

transmitting during a fourth interval said second delayed amplified received spread spectrum signal;

wherein the method of amplifying said spread spectrum signal further comprises the steps of;

detecting a first gain of said transmitted spread spectrum signal; and

adjusting a second gain in said step of amplifying said second received spread spectrum signal based on said first gain.

35. A method of amplifying a spread spectrum signal, said spread spectrum signal comprised of a series of code symbols, said method comprising the steps of:

receiving during a first interval said spread spectrum signal;

amplifying said received spread spectrum signal;

delaying said amplified received spread spectrum signal by a predetermined amount;

transmitting during a second interval said delayed amplified received spread spectrum signal;

wherein said step of receiving and said step of transmitting are mutually exclusive events and wherein the method of amplifying said spread spectrum signal further comprises the steps of;

receiving during a third interval a second spread spectrum signal;

amplifying said second received spread spectrum signal;

delaying said second amplified received spread spectrum signal by a second predetermined amount;

transmitting during a fourth interval said second delayed amplified received spread spectrum signal;

wherein the method of amplifying a spread spectrum signal further comprises the steps of;

transmitting a reverse link communication signal within said second spread spectrum signal;

receiving and demodulating a forward link communication signal within said spread spectrum signal to determine a gain adjustment signal contained therein; and

adjusting a gain in said step of amplifying said second received spread spectrum signal according to said gain adjustment signal.

36. An apparatus for amplifying a spread spectrum signal comprising:

means for receiving intermittently said spread spectrum signal;

means for amplifying said received spread spectrum signal;

means for delaying said amplified received spread spectrum signal by a predetermined amount;

means for transmitting intermittently said delayed amplified received spread spectrum signal;

wherein said means for receiving intermittently and said means for transmitting intermittently operate mutually exclusively such that said delayed amplified received spread spectrum signal is transmitted only or said spread spectrum signal is received only;

wherein the apparatus for amplifying said spread spectrum signal further comprises;

means for receiving intermittently a second spread spectrum signal;

means for amplifying said second received spread spectrum signal;

means for delaying said second amplified received spread spectrum signal by a second predetermined amount;

means for transmitting intermittently said second delayed amplified received spread spectrum signal;

wherein the apparatus for amplifying said spread spectrum signal further comprises;

means for transmitting a reverse link communication signal within said second spread spectrum signal;

means for receiving and demodulating a forward link communication signal within said spread spectrum signal to determine a gain adjustment signal contained therein; and

means for adjusting a gain in said step of amplifying said second received spread spectrum signal according to said gain adjustment signal.

37. A time division duplex repeater for amplifying a spread spectrum signal comprising:

a first antenna receiving a forward link signal;

an amplifier coupled to said first antenna;

a delay device coupled in series with said first antenna and said amplifier;

a second antenna coupled in series with said first antenna, said amplifier, and said delay device for providing a repeated forward link signal;

an isolation device coupled in series with said amplifier, said first and second antennas, and said delay device for intermittently disrupting a connection of said forward link signal to said delay device while said repeated forward link signal is provided by said second antenna;

wherein the time division duplex repeater for amplifying said spread spectrum signal further comprises;

a third antenna receiving a reverse link signal;

a reverse link amplifier coupled to said third antenna;

a reverse link delay device coupled in series with said third antenna and said reverse link amplifier;

a fourth antenna coupled in series with said third antenna, said reverse link amplifier and said reverse link delay device for providing a repeated reverse link signal;

a reverse link isolation device coupled in series with said reverse link amplifier, said third and fourth antennas, and said reverse link delay device for intermittently disrupting a connection of said reverse link signal to said reverse link delay device while said repeated reverse link signal is provided by said fourth antenna;

wherein the time division duplex repeater for amplifying said spread spectrum signal further comprises;

a variable gain amplifier in series with said reverse link isolation device, said reverse link amplifier, said third and fourth antennas, and said reverse link delay device and receiving a gain control signal; and

a mobile unit providing a first communication signal within said reverse link signal and receiving a second communication signal from within said repeated forward link signal, and providing said gain control signal.