Repeater system for strong signal environments

• US 20060084379A1
• Filed: 11/30/2005
• Published: 04/20/2006
• Est. Priority Date: 03/04/2003
• Status: Active Grant

• Current Assignee: Cufer Asset Ltd LLC (Intellectual Ventures LLC)
• Original Assignee: Bandwidth Wireless LLC (Intellectual Ventures LLC)
• Inventors: O'Neill, Frank P.
• Granted Patent: US 7,555,261 B2
• Time in Patent Office: Days
• US Class Current: 455/25
• 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 7/15571 by signal isolation, e.g. isolation by frequency or by antenna pattern, or by polarization
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• CPC Class Codes: H04W 88/04 adapted for relaying to or from another terminal or user

Abstract

A repeater system combines co-located antennas, an intentional imbalance in signal amplification between downlink and uplink, stability management and an amplification indicator to create a user-installed solution to co-channel interference within cellular systems, in strong signal environments such as elevated locations or high-rise building. The invention may be particularly relevant to cellular systems, such as CDMA, that allow limited imbalance between uplink and downlink path losses, thus enabling the design of an inexpensive repeater with a weaker or non-existent uplink, and which creates moderate signal amplification for selected line-of-sight signals, defeating co-channel interference over a small area. The difference in signal amplification on the downlink and uplink is maintained at a level below the capacity of the system to support imbalance, guaranteeing reliable cellular calls.

Claims

1. A repeater for a 2-way mobile communication system having a plurality of base stations and subscriber units that communicate via RF signals, comprising:

a base-side antenna that is directed toward at least one of the base stations to receive transmitted RF signals from the base station, the antenna generating a received downlink signal therefrom;

an amplifier receptive of the received downlink signal, the amplifier amplifying the level of the received downlink signal to generate an amplified downlink signal; and

a subscriber-side antenna located proximate to the base-side antenna, the subscriber-side antenna being receptive of the amplified downlink signal, the subscriber-side antenna transmitting RF signals representative of the amplified downlink signal within a local area to subscriber units located nearby;

wherein the repeater operates in the downlink direction between the base station and the subscriber units near the repeater; and

said repeater further including amplification in the uplink direction which is substantially less than the amplification used in the downlink, comprising;

a subscriber-side antenna receiving RF signals within a local area from subscriber units located nearby, the antenna generating an uplink received signal therefrom;

an amplifier receptive of the received uplink signal, the amplifier amplifying the received uplink signal by a substantially smaller level then used in the downlink, and which generates an amplified uplink signal; and

a base-side antenna that is directed toward at least one of the base stations, the subscriber-side antenna being receptive of the amplified uplink signal, and which transmits RF signals representative of the amplified uplink signal to the base station;

wherein the repeater operates in the uplink direction between the subscriber and the base station units near the repeater and the presence of the repeater in the downlink and uplink directions causes an intentional imbalance in total losses between the downlink and the uplink, in order to provide for signal enhancement in both uplink and downlink over an equivalent coverage area.

2. A repeater as defined in claim 1, wherein the RF signals received by the base-side antenna and the RF signals transmitted by the subscriber-side antenna are at substantially the same frequency, which is different from the frequency of the RF signals received by the subscriber-side antenna and the RF signals transmitted by the base-side antenna.

3. A repeater as defined in claim 1, further including a repeater housing in which the subscriber-side and base-side antennas are located.

4. A repeater as defined in claim 1, wherein the base-side and subscriber-side antennas are located within two meters of each other.

5. A repeater as defined in claim 1, wherein the amplifier includes circuitry therein to substantially prevent saturation.

6. A repeater as defined in claim 5, wherein the circuitry substantially prevents saturation by periodically incrementing the magnitude of amplification toward an oscillation condition and testing for same.

7. A repeater as defined in claim 6, wherein the circuitry resets the magnitude of amplification to a smaller level during periodic testing for oscillation, and to a much smaller level for sudden occurrences of oscillation, in order to minimize the length of time for which steady amplification is interrupted.

8. A repeater as defined in claim 7, wherein the period with which the circuitry resets the magnitude of amplification is gradually increased from a relatively shorter duration toward a relatively longer duration if successive tests for oscillation indicate a steady and adequate amplification setting, and wherein the reset period may be decreased when oscillation is detected.

9. A repeater as defined in claim 1, wherein the base-side and subscriber-side antennas of the repeater are positionable by the operator for signal enhancement.

10. A repeater as defined in claim 1, wherein the amplifier provides an external indication of the magnitude of amplification and wherein the subscriber uses the external indication to optimally position the base-side and subscriber-side antennas of the repeater.

11. A repeater as defined in claim 1, wherein the repeater is effective in substantially eliminating co-channel interference in the vicinity of the repeater.

12. A repeater as defined in claim 1, wherein the repeater is effective in substantially eliminating co-channel interference within ten meters of the repeater.

13. A repeater as defined in claim 1, wherein the subscriber units and the base-side and subscriber-side antennas of the repeater are all located in the vicinity of each other and all are in an environment receiving signals of adequate signal strength from multiple base stations.

14. A repeater as defined in claim 1, wherein the mobile communication system includes a downlink direction in which signals are transmitted from the base stations to the subscriber units and an uplink direction in which signals are transmitted from the subscriber units to the base stations and wherein the repeater system is employed in both the downlink and uplink directions, creating an intentional imbalance in order to resolve co-channel interference while minimizing the risk of interference to the same communication system or to other communication systems.

15. A repeater as defined in claim 1, wherein the amplifier includes circuitry therein to substantially prevent saturation.

16. A repeater as defined in claim 1, wherein the base-side and subscriber-side antennas are isolated from each other using cross-polarization achieved by mechanical orientation or by electrical rotation.

17. A repeater as defined in claim 1, wherein the base-side and subscriber-side antennas are isolated from each other using a metallic chassis.

18. A repeater as defined in claim 1, wherein the difference in uplink and downlink amplification is limited in magnitude to maintain the capacity of the mobile communications system to support link imbalance in a 2-way system.

19. A repeater as defined in claim 1, further including a secondary interior repeater for two-way amplification between the first repeater and the subscriber.

20. A repeater system for a 2-way mobile communication system having a plurality of base stations and subscriber units that communicate via RF signals, comprising:

a first repeater including;

a base-side antenna that is directed toward at least one of the base stations to receive transmitted RF signals from the base station, the antenna generating a received downlink signal therefrom;

an amplifier receptive of the received downlink signal, the amplifier amplifying the level of the received downlink signal to generate an amplified downlink signal; and

a subscriber-side antenna located proximate to the base-side antenna, the subscriber-side antenna being receptive of the amplified downlink signal, the subscriber-side antenna transmitting RF signals representative of the amplified downlink signal within a local area;

a second repeater including;

a base-side antenna that is directed toward the first repeater to receive transmitted RF signals from the first repeater, the antenna generating a received downlink signal therefrom;

an amplifier receptive of the received downlink signal, the amplifier amplifying the level of the received downlink signal to generate an amplified downlink signal; and

a subscriber-side antenna located proximate to the base-side antenna, the subscriber-side antenna being receptive of the amplified downlink signal, the subscriber-side antenna transmitting RF signals representative of the amplified downlink signal within a local area to subscriber units located nearby;

wherein the second repeater operates in the downlink direction between the base station and the local area; and

said second repeater further including amplification in the uplink direction which is substantially less than the amplification used in the downlink, wherein the subscriber-side antenna of the second repeater receives RF signals within a local area from subscriber units located nearby, the antenna generating an uplink received signal therefrom, wherein the amplifier of the second repeater is receptive of the received uplink signal, the amplifier amplifying the received uplink signal by a substantially smaller level then used in the downlink and generating an amplified uplink signal, and wherein the base-side antenna of the second repeater is directed generally toward at least one of the base stations, the base-side antenna being receptive of the amplified uplink signal and transmitting RF signals representative of the amplified uplink signal to the at least one of the base stations;

wherein the second repeater operates in the uplink direction between the subscriber and the first repeater and the presence of the second repeater in the downlink and uplink directions causes an intentional imbalance in total losses between the downlink and the uplink, in order to provide for signal enhancement in both uplink and downlink over an equivalent coverage area.

21. A repeater for a mobile communication system having a plurality of base stations and subscriber units that communicate via RF signals, comprising:

a base-side antenna that is directed toward one of the base stations to receive transmitted RF signals from the base station, the base-side antenna generating a received signal therefrom;

an amplifier receptive of the received signal, the amplifier amplifying the level of the received signal to generate an amplified signal, the amplifier including circuitry therein to substantially prevent saturation by incrementing the magnitude of amplification toward an oscillation condition and testing for same; and

a subscriber-side antenna located proximate to the base-side antenna, the subscriber-side antenna being receptive of the amplified signal, the subscriber-side antenna transmitting RF signals within a local area to subscriber units located nearby.

22. A repeater as defined in claim 21, further including a repeater housing in which the base-side and subscriber-side antennas are located.

23. A repeater as defined in claim 21, wherein the repeater includes an uplink amplifier of substantially less amplification than the downlink amplifier.

24. A repeater as defined in claim 21, wherein the mobile telecommunication system includes a downlink direction in which signals are transmitted from the base stations to the subscriber units and an uplink direction in which signals are transmitted from the subscriber units to the base stations, and wherein the presence of the repeater causes an intentional imbalance in total losses between the downlink and the uplink directions.

25. A repeater as defined in claim 24, wherein the amplification is limited in magnitude to maintain the capacity of the mobile communication system to support link imbalance.

26. A repeater as defined in claim 21, wherein the repeater is effective in substantially eliminating co-channel interference in the vicinity of the repeater.

27. A repeater as defined in claim 21, wherein the repeater is effective in substantially eliminating co-channel interference within ten meters of the repeater.

28. A repeater as defined in claim 21, wherein the subscriber units and the base-side and subscriber-side antennas of the repeater are all located in the vicinity of each other and all are receiving signals of adequate signal strength from multiple base stations.

29. A repeater as defined in claim 21, wherein the mobile telecommunication system includes a downlink direction in which signals are transmitted from the base stations to the subscriber units and an uplink direction in which signals are transmitted from the subscriber units to the base stations and wherein the repeater system is employed in the downlink direction only.

30. A repeater as defined in claim 21, wherein the mobile telecommunication system includes a downlink direction in which signals are transmitted from the base stations to the subscriber units and an uplink direction in which signals are transmitted from the subscriber units to the base stations and wherein the repeater system is employed in both the downlink and uplink directions, creating an intentional imbalance in order to provide enhanced subscriber service while minimizing the risk of interference to the same communication system or to other communication systems.

31. A repeater as defined in claim 21, wherein the saturation-prevention circuitry resets the magnitude of amplification to a smaller level during periodic testing for oscillation, and to a much smaller level for sudden occurrences of oscillation, in order to minimize the length of time for which steady amplification is interrupted.

32. A repeater as defined in claim 21, wherein the elapsed time after which the circuitry resets the magnitude of amplification is gradually increased from a relatively shorter duration toward a relatively longer duration if successive tests for oscillation indicate a steady and adequate amplification setting, and wherein the reset period may be decreased when oscillation is detected.

33. A method for substantially eliminating co-channel interference in a local area containing subscriber units receiving adequate signals from a plurality of base stations, comprising:

co-locating a subscriber-side antenna and a base-side antenna within an environment receiving signals of adequate signal strength from multiple base stations to provide downlink amplification and substantially lower uplink amplification,

wherein the lower level of uplink amplification substantially reduces the risk of creating interference to the same communication system or to other communication systems.

34. A method as defined in claim 33, wherein link imbalance is intentionally caused between the downlink and the uplink directions, said link imbalance being less than the telecommunication system'"'"'s capacity for tolerating link imbalance.

35. A method as defined in claim 33, further including substantially preventing saturation by periodically testing for oscillation with a minimum of service interruption and then setting the amplification to a maximum magnitude.