Spread-spectrum handoff and source congestion avoidance system and method

• US 6,314,126 B1
• Filed: 01/12/2001
• Issued: 11/06/2001
• Est. Priority Date: 01/12/2001
• Status: Expired due to Term

• Current Assignee: Hydro Net LLC (IP Edge LLC)
• Original Assignee: Linex Technologies, Inc.
• Inventors: Schilling, Donald L., Garodnick, Joseph
• Primary Examiner(s): VO, DON NGUYEN
• Application Number:
  US09/758,981
• Time in Patent Office: 298 Days
• Field of Search: 375/130, 375/141, 370/331, 370/332, 370/335, 455/436, 455/437, 455/438, 455/439, 455/442
• US Class Current: 375/130
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/302 due to low signal strength
• CPC Class Codes: H04W 52/16 Deriving transmission power values from another channel
• 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

Abstract

A spread-spectrum, code-division-multiple-access (CDMA), system with a remote station (RS) communicating with a first base station (BS). The remote station receives the first BS-packet signal, and transmits a first RS-packet signal to the first base station. The first RS-packet signal is spread by a first RS-chip-sequence signal at a second frequency. The first base station receives the first RS-packet signal. The first base station stores and forwards the despread first RS-packet signal to a central office (CO). The remote station monitors control and packet transmission channels of other base stations in geographic proximity to the remote station. Each of the base stations transmit BS-packet signals. The remote station determines, based on signal metrics and available capacity, when to change from the first base station to the second base station. The second base station stores and then forwards the despread second RS-packet signal to the central office. The despread second RS-packet signal includes a source address from the second base station and the source address from the remote station. For return communications from the central office, the central office reads the source address from the second base station, and routes return packet signals, denoted herein as CO-packet through the second base station to the remote station.

Claims

1. An improvement method to a spread-spectrum system comprising the steps of:

transmitting, using radio waves, from a first base station (BS) a first BS-packet signal spread by a first BS-chip-sequence signal at a first frequency;

receiving at a remote station (RS) the first BS-packet signal;

transmitting, using radio waves, from said first base station a first BS-channel-sounding signal at a second frequency;

receiving at said remote station the first BS-channel-sounding signal at the second frequency;

tracking at said remote station the first BS-channel-sounding signal, thereby outputting a first RS-receiver signal;

adjusting, in response to the first RS-receiver signal, a first initial RS-power level of said remote station;

transmitting, using radio waves, from said remote station (RS), a first RS-packet signal spread by a first RS-chip-sequence signal at a second frequency, at the initial RS-power level;

receiving at said first base station the first RS-packet signal at the second frequency;

sending the first RS-packet signal to a central office from the first base station, with the first RS-packet signal including a source address from the first base station;

transmitting, using radio waves, from a second base station a second BS-packet signal spread by a second BS-chip-sequence signal at the first frequency;

transmitting, using radio waves, from said second base station a second BS-channel-sounding signal at the second frequency, with the second BS-channel-sounding signal having a bandwidth no more than twenty per cent of the spread-spectrum bandwidth of the first BS-packet signal spread by the first BS-chip-sequence signal at the first frequency;

monitoring at said remote station a signal metric of the first BS-packet signal and a signal metric of the first BS-channel-sounding signal, and a signal metric of the second BS-packet signal and a signal metric of the second BS-channel-sounding signal;

determining at said remote station that the signal metric of at least one of the first BS-packet signal and the first BS-channel-sounding signal fall below a threshold, and that the signal metric of at least one of the second BS-packet signal and the second BS-channel-sounding signal are above the threshold, and that the second base station has available capacity, thereby determining to change base stations;

receiving at said remote station the second BS-channel-sounding signal at the second frequency;

tracking at said remote station the second BS-channel-sounding signal, thereby outputting a second RS-receiver signal;

adjusting, in response to the second RS-receiver signal, a second initial RS-power level of said remote station;

transmitting, using radio waves, from said remote station (RS), a second RS-packet signal spread by a second RS-chip-sequence signal at the second frequency, at the second initial RS-power level;

transmitting, using radio waves, in response to determining to change base stations, from said remote station a second RS-packet signal spread by a second RS-chip-sequence signal at the second frequency;

receiving at said second base station the second RS-packet signal at the second frequency;

sending the second RS-packet signal to a central office (CO) from the second base station, with the second RS-packet signal including a source address from the second base station;

sending from said central office a CO-packet signal including a destination address for the second base station;

receiving at said second base station the CO-packet signal;

transmitting, using radio waves, from said second base station the CO-packet signal the first frequency; and

receiving at said remote station the CO-packet signal.

2. The improvement as set forth in claim 1, wherein the step of transmitting from said first base station the first BS-channel-sounding signal includes the step of transmitting from said first base station the first BS-channel sounding signal, with the first BS-channel-sounding signal having a bandwidth no more than twenty per cent of a spread-spectrum bandwidth of the first BS-packet signal spread by the first BS-chip-sequence signal at the first frequency.

3. The improvement as set forth in claim 1, wherein the step of transmitting from said first base station the first BS-channel-sounding signal includes the step of transmitting from said first base station the first BS-channel sounding signal, with the first BS-channel-sounding signal having a bandwidth no more than ten per cent of a spread-spectrum bandwidth of the first BS-packet signal spread by the first BS-chip-sequence signal at the first frequency.

4. The improvement as set forth in claim 1, wherein the step of transmitting from said first base station the first BS-channel-sounding signal includes the step of transmitting from said first base station the first BS-channel sounding signal, with the first BS-channel-sounding signal having a bandwidth no more than five per cent of a spread-spectrum bandwidth of the first BS-packet signal spread by the first BS-chip-sequence signal at the first frequency.

5. The improvement as set forth in claim 1, wherein the step of transmitting from said first base station the first BS-channel-sounding signal includes the step of transmitting from said first base station the first BS-channel sounding signal, with the first BS-channel-sounding signal having a bandwidth no more than one per cent of a spread-spectrum bandwidth of the first BS-packet signal spread by the first BS-chip-sequence signal at the first frequency.

6. An improvement method to a spread-spectrum system comprising the steps of:

transmitting from a first base station (BS) a first BS-packet signal spread by a first BS-chip-sequence signal at a first frequency;

receiving at a remote station (RS) the first BS-packet signal;

transmitting from a second base station a second BS-packet signal spread by a second BS-chip-sequence signal at the first frequency;

monitoring at said remote station, a plurality of base stations, including a signal metric of the first BS-packet signal and a signal metric of the second BS-packet signal;

determining at said remote station that the signal metric of the first BS-packet signal falls below a threshold and that the signal metric of the second BS-packet signal is above the threshold, thereby deciding to change base stations;

transmitting, in response to determining to change base stations, from said remote station an RS-packet signal spread by an RS-chip-sequence signal at a second frequency;

receiving at said second base station the RS-packet signal at the second frequency;

storing at the second base station the RS-packet signal;

forwarding the RS-packet signal to a central office (CO) from the second base station, with the RS-packet signal including a source address from the second base station;

sending from said central office a CO-packet signal including a destination address for the second base station;

receiving at said second base station the CO-packet signal;

transmitting from said second base station the CO-packet signal spread by the second BS-chip-sequence signal the first frequency; and

receiving at said remote station the CO-packet signal.

7. The method as s et forth in claim 6, with the step of transmitting from said remote station the RS-packet signal spread by the RS-chip-sequence signal at the second frequency includes the step of transmitting from said remote station the RS-packet signal at the second frequency, with the second frequency equal to the first frequency.

8. The method as set forth in claim 6, with the step of transmitting from said remote station the RS-packet signal spread by the RS-chip-sequence signal at the second frequency includes the step of transmitting from said remote station the RS-packet signal at the second frequency, with the second frequency outside a correlation bandwidth of the first frequency.

9. The method as set forth in claim 6, with the step of determining at said remote station the signal metric further including the step of determining that the second base station has available capacity, in order to change base stations.

10. The method as set forth in claim 7, with the step of determining at said remote station the signal metric further including the step of determining that the second base station has available capacity, in order to change base stations.

11. The method as set forth in claim 8, with the step of determining at said remote station the signal metric further including the step of determining that the second base station has available capacity, in order to change base stations.

12. An improvement method to a spread-spectrum system comprising the steps of:

transmitting from a first base station (BS) a first BS-packet signal spread by a first BS-chip-sequence signal at a first frequency;

receiving at a remote station (RS) the first BS-packet signal;

transmitting from said remote station (RS) a first RS-packet signal spread by a first RS-chip-sequence signal at a second frequency;

receiving at said first base station the first RS-packet signal at the second frequency;

sending the first RS-packet signal to a central office from the first base station, with the first RS-packet signal including a source address from the first base station;

transmitting from a second base station a second BS-packet signal spread by a second BS-chip-sequence signal at the first frequency;

monitoring at said remote station a signal metric of the first BS-packet signal and a signal metric of the second BS-packet signal;

determining at said remote station that the signal metric of the first BS-packet signal falls below a threshold and the signal metric of the second BS-packet signal is above the threshold, and that the second base station has available capacity, thereby changing base stations;

transmitting, in response to determining to change base stations, from said remote station a second RS-packet signal spread by a second RS-chip-sequence signal at the second frequency;

receiving at said second base station the second RS-packet signal at the second frequency;

sending the second RS-packet signal to a central office (CO) from the second base station, with the second RS-packet signal including a source address from the second base station;

sending from said central office a CO-packet signal including a destination address for the second base station;

receiving at said second base station the CO-packet signal;

transmitting from said second base station the CO-packet signal the first frequency; and

receiving at said remote station the CO-packet signal.

13. An improvement to a spread-spectrum system comprising:

a first base station (BS) for transmitting, using radio waves, a first BS-packet signal spread by a first BS-chip-sequence signal at a first frequency, and for transmitting, using radio waves, a first BS-channel-sounding signal at a second frequency;

a remote station (RS) for receiving the first BS-packet signal, for receiving the first BS-channel-sounding signal at the second frequency, and for tracking the first BS-channel-sounding signal, thereby outputting a first RS-receiver signal, said remote station for adjusting, responsive to the first RS-receiver signal, a first initial RS-power level of said remote station, and for transmitting, using radio waves, a first RS-packet signal spread by a first RS-chip-sequence signal at a second frequency, at the initial RS-power level;

said first base station for receiving the first RS-packet signal at the second frequency, and for sending the first RS-packet signal to a central office from the first base station, with the first RS-packet signal including a source address from the first base station;

a second base station for transmitting, using radio waves, a second BS-packet signal spread by a second BS-chip-sequence signal at the first frequency, for transmitting, using radio waves, a second BS-channel-sounding signal at the second frequency;

said remote station for monitoring a signal metric of the first BS-packet signal and a signal metric of the first BS-channel-sounding signal, and a signal metric of the second BS-packet signal and a signal metric of the second BS-channel-sounding signal, said remote station for determining that the signal metric of at least one of the first BS-packet signal and the first BS-channel-sounding signal fall below a threshold, and that the signal metric of at least one of the second BS-packet signal and the second BS-channel-sounding signal are above the threshold, and that the second base station has available capacity, thereby determining to change base stations;

said remote station for receiving the second BS-channel-sounding signal at the second frequency, and for tracking the second BS-channel-sounding signal, thereby outputting a second RS-receiver signal, and for adjusting, in response to the second RS-receiver signal, a second initial RS-power level of said remote station;

said remote station (RS) for transmitting, using radio waves, a second RS-packet signal spread by a second RS-chip-sequence signal at the second frequency, at the second initial RS-power level, and for transmitting, using radio waves, in response to determining to change base stations, a second RS-packet signal spread by a second RS-chip-sequence signal at the second frequency;

said second base station for receiving the second RS-packet signal at the second frequency, and for sending the second RS-packet signal to a central office (CO), with the second RS-packet signal including a source address from the second base station;

said central office for sending a CO-packet signal including a destination address for the second base station;

said second base station for receiving the CO-packet signal;

said second base station for transmitting, using radio waves, the CO-packet signal the first frequency; and

said remote station for receiving the CO-packet signal.

14. The improvement as set forth in claim 13, wherein the said first base station includes means for transmitting the first BS-channel sounding signal, with the first BS-channel-sounding signal having a bandwidth no more than twenty per cent of a spread-spectrum bandwidth of the first BS-packet signal spread by the first BS-chip-sequence signal at the first frequency.

15. The improvement as set forth in claim 13, wherein the said first base station includes means for transmitting the first BS-channel sounding signal, with the first BS-channel-sounding signal having a bandwidth no more than ten per cent of a spread-spectrum bandwidth of the first BS-packet signal spread by the first BS-chip-sequence signal at the first frequency.

16. The improvement as set forth in claim 13, wherein the said first base station includes means for transmitting the first BS-channel sounding signal, with the first BS-channel-sounding signal having a bandwidth no more than five per cent of a spread-spectrum bandwidth of the first BS-packet signal spread by the first BS-chip-sequence signal at the first frequency.

17. The improvement as set forth in claim 13, wherein the said first base station includes means for transmitting the first BS-channel sounding signal, with the first BS-channel-sounding signal having a bandwidth no more than one per cent of a spread-spectrum bandwidth of the first BS-packet signal spread by the first BS-chip-sequence signal at the first frequency.

18. An improvement a spread-spectrum system comprising the steps of:

a first base station (BS) for transmitting a first BS-packet signal spread by a first BS-chip-sequence signal at a first frequency;

a remote station (RS) for receiving the first BS-packet signal;

a second base station for transmitting a second BS-packet signal spread by a second BS-chip-sequence signal at a first frequency;

said remote station for monitoring a signal metric of the first BS-packet signal and a signal metric of the second BS-packet signal, for determining that the signal metric of the first BS-packet signal falls below a threshold and that the signal metric of the second BS-packet signal is above the threshold, thereby deciding to change base stations, and for transmitting, in response to determining to change base stations, an RS-packet signal spread by an RS-chip-sequence signal at a second frequency;

said second base station for the RS-packet signal at the second frequency, and for sending the RS-packet signal to a central office (CO), with the RS-packet signal including a source address from the second base station;

said central office for sending a CO-packet signal including a destination address for the second base station;

said second base station for receiving the CO-packet signal, and for transmitting the CO-packet signal spread by the second BS-chip-sequence signal the first frequency; and

said remote station for transmitting the CO-packet signal.

19. The improvement as set forth in claim 18, with said remote station transmitting the RS-packet signal with the second frequency equal to the first frequency.

20. The improvement as set forth in claim 18, with said remote station transmitting the RS-packet signal with the second frequency outside a correlation bandwidth of the first frequency.

21. The improvement as set forth in claim 18, with said remote station including means for determining that the second base station has available capacity, in order to change base stations.

22. The improvement as set forth in claim 18, with said remote station further including means for determining that the second base station has available capacity, in order to change base stations.

23. The improvement as set forth in claim 19, with said remote station further including means for determining that the second base station has available capacity, in order to change base stations.

24. An improvement to a spread-spectrum system comprising:

first base-station (BS) means for transmitting, using radio waves, a first BS-packet signal spread by a first BS-chip-sequence signal at a first frequency, and for transmitting, using radio waves, a first BS-channel-sounding signal at a second frequency;

remote-station (RS) means for receiving the first BS-packet signal, for receiving the first BS-channel-sounding signal at the second frequency, and for tracking the first BS-channel-sounding signal, thereby outputting a first RS-receiver signal, said remote station for adjusting, responsive to the first RS-receiver signal, a first initial RS-power level of said remote station, and for transmitting, using radio waves, a first RS-packet signal spread by a first RS-chip-sequence signal at a second frequency, at the initial RS-power level;

said first base-station means for receiving the first RS-packet signal at the second frequency, and for sending the first RS-packet signal to a central office from the first base station, with the first RS-packet signal including a source address from the first base station;

second base-station means for transmitting, using radio waves, a second BS-packet signal spread by a second BS-chip-sequence signal at the first frequency, for transmitting, using radio waves, a second BS-channel-sounding signal at the second frequency;

said remote-station means for monitoring a signal metric of the first BS-packet signal and a signal metric of the first BS-channel-sounding signal, and a signal metric of the second BS-packet signal and a signal metric of the second BS-channel-sounding signal, said remote station for determining that the signal metric of at least one of the first BS-packet signal and the first BS-channel-sounding signal fall below a threshold, and that the signal metric of at least one of the second BS-packet signal and the second BS-channel-sounding signal are above the threshold, and that the second base station has available capacity, thereby determining to change base stations;

said remote-station means for receiving the second BS-channel-sounding signal at the second frequency, and for tracking the second BS-channel-sounding signal, thereby outputting a second RS-receiver signal, and for adjusting, in response to the second RS-receiver signal, a second initial RS-power level of said remote station;

said remote-station (RS) means for transmitting, using radio waves, a second RS-packet signal spread by a second RS-chip-sequence signal at the second frequency, at the second initial RS-power level, and for transmitting, using radio waves, in response to determining to change base stations, a second RS-packet signal spread by a second RS-chip-sequence signal at the second frequency;

said second base-station means for receiving the second RS-packet signal at the second frequency, and for sending the second RS-packet signal to central-office (CO) means, with the second RS-packet signal including a source address from the second base station;

said central-office means for sending a CO-packet signal including a destination address for the second base station;

said second base-station means for receiving the CO-packet signal, and for transmitting, using radio waves, the CO-packet signal the first frequency; and

said remote-station means for receiving the CO-packet signal.

25. The improvement as set forth in claim 24, wherein the said first base-station means includes means for transmitting the first BS-channel sounding signal, with the first BS-channel-sounding signal having a bandwidth no more than ten per cent of a spread-spectrum bandwidth of the first BS-packet signal spread by the first BS-chip-sequence signal at the first frequency.

26. The improvement as set forth in claim 24, wherein the said first base-station means includes means for transmitting the first BS-channel sounding signal, with the first BS-channel-sounding signal having a bandwidth no more than ten per cent of a spread-spectrum bandwidth of the first BS-packet signal spread by the first BS-chip-sequence signal at the first frequency.

27. The improvement as set forth in claim 24, wherein the said first base-station means includes means for transmitting the first BS-channel sounding signal, with the first BS-channel-sounding signal having a bandwidth no more than five per cent of a spread-spectrum bandwidth of the first BS-packet signal spread by the first BS-chip-sequence signal at the first frequency.

28. The improvement as set forth in claim 24, wherein the said first base-station means includes means for transmitting the first BS-channel sounding signal, with the first BS-channel-sounding signal having a bandwidth no more than one per cent of a spread-spectrum bandwidth of the first BS-packet signal spread by the first BS-chip-sequence signal at the first frequency.

29. An improvement a spread-spectrum system comprising the steps of:

first base-station (BS) means for transmitting a first BS-packet signal spread by a first BS-chip-sequence signal at a first frequency;

remote-station (RS) means for receiving the first BS-packet signal;

second base-station means for transmitting a second BS-packet signal spread by a second BS-chip-sequence signal at a first frequency;

said remote-station means for monitoring a signal metric of the first BS-packet signal and a signal metric of the second BS-packet signal, for determining that the signal metric of the first BS-packet signal falls below a threshold and that the signal metric of the second BS-packet signal is above the threshold, thereby deciding to change base stations, and for transmitting, in response to determining to change base stations, an RS-packet signal spread by an RS-chip-sequence signal at a second frequency;

said second base-station means for the RS-packet signal at the second frequency, and for sending the RS-packet signal to central-office (CO) means, with the RS-packet signal including a source address from the second base station;

said central-office means for sending a CO-packet signal including a destination address for the second base station;

said second base-station means for receiving the CO-packet signal, and for transmitting the CO-packet signal spread by the second BS-chip-sequence signal the first frequency; and

said remote-station means for transmitting the CO-packet signal.

30. The improvement as set forth in claim 29, with said remote-station means transmitting the RS-packet signal with the second frequency equal to the first frequency.

31. The improvement as set forth in claim 29, with said remote-station means transmitting the RS-packet signal with the second frequency outside a correlation bandwidth of the first frequency.

32. The improvement as set forth in claim 29, with said remote-station means including means for determining that the second base station has available capacity, in order to change base stations.

33. The improvement as set forth in claim 29, with said remote-station means further including means for determining that the second base station has available capacity, in order to change base stations.

34. The improvement as set forth in claim 30, with said remote-station means further including means for determining that the second base station has available capacity, in order to change base stations.