Spectrally efficient high capacity wireless communication systems

• US 5,592,490 A
• Filed: 01/20/1995
• Issued: 01/07/1997
• Est. Priority Date: 12/12/1991
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: ArrayComm LLC (Ygomi LLC)
• Inventors: Barratt, Craig H., Parish, David M., Roy, III, Richard H.
• Primary Examiner(s): Safourek, Benedict V.
• Assistant Examiner(s): Nguyen, Chau T.
• Application Number:
  US08/375,848
• Time in Patent Office: 718 Days
• Field of Search: 370/95.1, 370/95.3, 370/119, 342/368, 342/442, 342/378, 342/383, 342/384, 364/572, 364/574, 364/578, 364/581, 375/200, 375/205, 455/33.3, 455/63
• US Class Current: 370/310
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
• CPC Class Codes: H01Q 3/267 Phased-array testing or checking devices
• CPC Class Codes: H04B 17/12 of transmit antennas, e.g. of the amplitude or phase
• CPC Class Codes: H04B 17/21 for calibration; for correcting measurements
• CPC Class Codes: H04B 7/0408 using two or more beams, i.e. beam diversity
• CPC Class Codes: H04B 7/0491 using two or more sectors, i.e. sector diversity
• CPC Class Codes: H04B 7/0615 of weighted versions of same signal
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0697 using spatial multiplexing
• CPC Class Codes: H04B 7/0842 Weighted combining
• CPC Class Codes: H04B 7/0845 per branch equalization, e.g. by an FIR-filter or RAKE receiver per antenna branch rake receivers as such H04B1/7115
• CPC Class Codes: H04W 16/28 using beam steering

Abstract

A wireless system comprising a network of base stations for receiving uplink signals transmitted from a plurality of remote terminals and for transmitting downlink signals to the plurality of remote terminals using a plurality of conventional channels including a plurality of antenna elements at each base station for receiving uplink signals, a plurality of antenna elements at each base station for transmitting downlink signals, a signal processor at each base station connected to the receiving antenna elements and to the transmitting antenna elements for determining spatial signatures and multiplexing and demultiplexing functions for each remote terminal antenna for each conventional channel, and a multiple base station network controller for optimizing network performance, whereby communication between the base stations and a plurality of remote terminals in each of the conventional channels can occur simultaneously.

Claims

1. A wireless system for calculating uplink signals transmitted from a plurality of remote terminals using a common uplink channel, said system including at least one base station, said system comprising:

receiving means at said at least one base station including a plurality of antenna elements and receivers for producing measurements of combinations of said uplink signals from said plurality of remote terminals using said common uplink channel,

receive spatial processing means for determining and storing receive spatial signatures for said plurality of remote terminals using said measurements, and

spatial demultiplexing means using said receive spatial signatures and said measurements to calculate said uplink signals.

2. The wireless system as defined by claim 1 wherein said receive spatial processing means comprises:

a spatial signature list comprising a receive spatial signature for each remote terminal in said plurality of remote terminals and said common uplink channel,

receive spatial signature determining means for determining said receive spatial signatures, and

a receive channel selector utilizing said receive spatial signatures to determine whether said common uplink channel can be further shared by an additional remote terminal.

3. The wireless system as defined by claim 2 wherein said receive spatial processing means further comprises:

a receive spatial weight processor for calculating spatial demultiplexing weights for said plurality of remote terminals, said spatial demultiplexing weights being utilized by said spatial demultiplexing means to calculate said uplink signals.

4. The wireless system as defined by claim 3 wherein said receive spatial weight processor determines said spatial demultiplexing weights as the columns of matrix W_rx as follows:

space="preserve" listing-type="equation">W.sub.rx =(A.sub.br P.sub.r A.sup.*.sub.br +R.sub.nn).sup.-1 A.sub.br P.sub.r

where ()^* denotes the complex conjugate transpose of a matrix, R_nn is the noise covariance matrix of said receiving means, P_r is the diagonal matrix of transmit powers of the remote terminals in said plurality of remote terminals, and A_br is a demultiplexing spatial signature matrix whose columns are said receive spatial signatures for said plurality of remote terminals and said common uplink channel.

5. The wireless system as defined by claim 1 wherein said common uplink channel is one of a plurality of uplink channels and wherein said receive spatial processing means comprises:

an active remote terminal list comprising a list of remote terminals assigned to at least one channel of said plurality of uplink channels,

a spatial signature list comprising a receive spatial signature for each remote terminal of said plurality of remote terminals and each channel of said plurality of uplink channels,

receive spatial signature determining means for determining said receive spatial signatures in said spatial signature list,

a receive channel selector using said active remote terminal list and said spatial signature list to determine assignments of each remote terminal in said active remote terminal list to at least one of the channels of said plurality of uplink channels, and

a receive spatial weight processor for calculating spatial demultiplexing weights for each of the terminals in said active remote terminal list and each channel of said plurality of uplink channels assigned to at least one of the terminals in said active remote terminal list, said spatial demultiplexing weights being utilized by said spatial demultiplexing means to calculate said uplink signals.

6. The wireless system as defined by claim 1 wherein said common uplink channel is one of a plurality of uplink channels, said at least one base station is one of a plurality of base stations, said receive spatial processing means is one of a plurality of receive spatial processing means, each base station in said plurality of base stations having a corresponding receive spatial processing means in said plurality of receive spatial processing means, each receive spatial processing means in said plurality of receive spatial processing means comprising:

an active remote terminal list comprising a list of remote terminals assigned to at least one channel of said plurality of uplink channels,

a spatial signature list comprising a receive spatial signature for each remote terminal of said plurality of remote terminals and each channel of said plurality of uplink channels,

receive spatial signature determining means for determining said receive spatial signatures in said spatial signature list, and

a receive spatial weight processor for calculating spatial demultiplexing weights for each of the terminals in said active remote terminal list and each channel of said plurality of uplink channels assigned to at least one of the terminals in said active remote terminal list, said spatial demultiplexing weights being utilized by said spatial demultiplexing means to calculate said uplink signals,

said system further comprising;

joint channel selector means for jointly determining assignments of each remote terminal in each said active remote terminal list to at least one of the channels of said plurality of uplink channels and to at least one of base stations of said plurality of base stations, and

communication means for communicating the status of said assignments between each base-station in said plurality of base stations and said joint channel selector means.

7. The wireless system as defined by claim 1 and including transmission means comprising a transmitter and an antenna for sending downlink signals from said at least one base station to the terminals in said plurality of remote terminals.

8. The wireless system as defined by claim 1 wherein said spatial demultiplexing means calculates spatial demultiplexing weights for said common uplink channel as the columns of a matrix W_rx as follows:

space="preserve" listing-type="equation">W.sub.rx =(A.sub.br P.sub.r A.sup.*.sub.br +R.sub.nn).sup.-1 A.sub.br P.sub.r

where ()^* denotes the complex conjugate transpose of a matrix, R_nn is the noise covariance matrix of said receiver means, P_r is the diagonal matrix of transmit powers of the remote terminals in said plurality of remote terminals, and A_br is a demultiplexing spatial signature matrix whose columns are said receive spatial signatures for said plurality of remote terminals and said common uplink channel, said spatial demultiplexing means using said spatial demultiplexing weights to calculate said uplink signals.

9. The wireless system as defined by claim 1 wherein said system includes a transponder co-located with each remote terminal of said plurality of remote terminals and wherein receive spatial processing means determines said receive spatial signatures using signals transponded from at least one of the transponders.

10. The wireless system as defined by claim 1 wherein each remote terminal of said plurality of remote terminals includes a transponder and said receive spatial processing means determines said receive spatial signatures using signals transponded from at least one of the transponders.

11. The wireless system as defined by claim 1 wherein said receive spatial processing means determines said receive spatial signatures using the known location and directivity of said antenna elements, and estimates of the directions of arrival of said uplink signals from said plurality of remote terminals.

12. The wireless system as defined by claim 1 wherein said receive spatial processing means determines said receive spatial signatures using the known location and directivity of said antenna elements and the known location of said plurality of remote terminals.

13. The wireless system as defined by claim 1 wherein said uplink signals have predetermined modulation format parameters, and said receive spatial processing means determines said receive spatial signatures using said predetermined modulation format parameters of said uplink signals from said plurality of remote terminals.

14. The wireless system as defined by claim 1 further comprising:

transmission means including a plurality of transmit antenna elements and transmitters for transmitting multiplexed downlink signals to said plurality of remote terminals using a common downlink channel,

transmit spatial processing means for determining and storing transmit spatial signatures for said plurality of remote terminals, and

spatial multiplexing means using said transmit spatial signatures and downlink signals to produce said multiplexed downlink signals.

15. The wireless system as defined by claim 14 wherein said receiving means and said transmission means share common antenna elements using duplexers.

16. The wireless system as defined by claim 14 wherein said receiving means and said transmission means share common antenna elements using transmit/receive switches.

17. The wireless system as defined by claim 14 wherein said common uplink channel is one of a plurality of uplink channels, said common downlink channel is one of a plurality of downlink channels, and wherein said receive spatial processing means and said transmit spatial processing means comprise:

an active remote terminal list comprising a list of remote terminals assigned to at least one of the channels of said plurality of uplink channels and remote terminals assigned to at least one of the channels of said plurality of downlink channels,

a spatial signature list comprising a receive spatial signature for each remote terminal of said plurality of remote terminals and each channel of said plurality of uplink channels, and a transmit spatial signature for each remote terminal of said plurality of remote terminals and each channel of said plurality of downlink channels,

receive spatial signature determining means for determining said receive spatial signatures,

transmit spatial signature determining means for determining said transmit spatial signatures, and

a channel selector using said active remote terminal list and said spatial signature list to determine assignments of each remote terminal in said active remote terminal list to at least one of the channels of said plurality of uplink channels and at least one of the channels of said plurality of downlink channels.

18. The wireless system as defined by claim 17 wherein said receive spatial processing means and said transmit spatial processing means further comprise:

a receive spatial weight processor for calculating spatial demultiplexing weights for each of the terminals in said active remote terminals list to which a uplink channel is assigned and for each channel of said plurality of uplink channels assigned to at least one of the terminals in said active remote terminal list, said spatial demultiplexing weights being utilized by said spatial demultiplexing means to calculate said uplink signals, and

a transmit spatial weight processor for calculating spatial multiplexing weights for each of the terminals in said active remote terminal list to which a downlink channel is assigned and each channel of said plurality of downlink channels assigned to at least one of the terminals in said active remote terminal list, said spatial multiplexing weights being utilized by said spatial multiplexing means to produce said multiplexed downlink signals.

19. The wireless system as defined by claim 14 wherein said at least one base station is one of a plurality of base stations, said common uplink channel is one of a plurality of uplink channels, said common downlink channel is one of a plurality of downlink channels, said receive spatial processing means is one of a plurality of receive spatial processing means, said transmit spatial processing means is one of a plurality of transmit spatial processing means, each base station in said plurality of base stations having a corresponding receive spatial processing means in said plurality of receive spatial processing means and a corresponding transmit spatial processing means in said plurality of transmit spatial processing means, each receive spatial processing means in said plurality of receive spatial processing means and each transmit spatial processing means in said plurality of transmit spatial processing means comprising:

an active remote terminal list comprising a list of remote terminals assigned to at least one of the channels of said plurality of uplink channels and remote terminals assigned to at least one of the channels of said plurality of downlink channels,

a spatial signature list comprising a receive spatial signature for each remote terminal of said plurality of remote terminals and each channel of said plurality of uplink channels, and a transmit spatial signature for each remote terminal of said plurality of remote terminals and each channel of said plurality of downlink channels,

receive spatial signature determining means for determining said receive spatial signatures,

transmit spatial signature determining means for determining said transmit spatial signatures,

a receive spatial weight processor for calculating spatial demultiplexing weights for each of the terminals in said active remote terminal list to which a uplink channel is assigned and each channel of said plurality of uplink channels assigned to at least one of the terminals in said active remote terminal list, said spatial demultiplexing weights being utilized by said spatial demultiplexing means to calculate said uplink signals, and

a transmit spatial weight processor for calculating spatial multiplexing weights for each of the terminals in said active remote terminal list to which a downlink channel is assigned and each channel of said plurality of downlink channels assigned to at least one of the terminals in said active remote terminal list, said spatial multiplexing weights being utilized by said spatial multiplexing means to produce said multiplexed downlink signals,

said system further comprising;

joint channel selector means for jointly determining assignments of each remote terminal in each said active remote terminal list to at least one of the channels of said plurality of uplink channels, to at least one of the channels of said plurality of downlink channels and to at least one of the base stations of said plurality of base stations, and

communication means for communicating said assignments between each base station in said plurality of base stations and said joint channel selector means.

20. The wireless system as defined by claim 14 wherein said spatial multiplexing means determines spatial multiplexing weights for said common downlink channel as the rows of a matrix W_tx as follows:

space="preserve" listing-type="equation">W.sub.tx =S.sub.b (A.sub.rb A.sup.*.sub.rb).sup.-1 A.sub.rb,

where ()^* denotes the complex conjugate transpose of a matrix, S_b is the diagonal matrix of amplitudes of said downlink signals, and A_rb is a multiplexing spatial signature matrix whose rows are said transmit spatial signatures for said plurality of remote terminals and said common downlink channel, and wherein said spatial multiplexing means utilizes said spatial multiplexing weights to produce said multiplexed downlink signals.

21. The wireless system as defined by claim 14 wherein said system includes a transponder co-located with each remote terminal of said plurality of remote terminals and wherein transmit spatial processing means determines said transmit spatial signatures using signals transponded from at least one of the transponders.

22. The wireless system as defined by claim 14 wherein each remote terminal in said plurality of remote terminals includes a transponder, and wherein said transmit spatial processing means determines said transmit spatial signatures using signals transponded from at least one of the transponders.

23. The wireless system as defined by claim 14 wherein said downlink signals have predetermined modulation format parameters, and said transmit spatial signatures are determined by the corresponding terminals in said plurality of remote terminals using the predetermined modulation format parameters of said downlink signals.

24. The wireless system as defined by claim 14 wherein said transmit spatial processing means determines said transmit spatial signatures using the known location and directivity of said transmit antenna elements and estimates of directions of arrival of said uplink signals from said plurality of remote terminals.

25. The wireless system as defined by claim 14 wherein said downlink signals and said uplink signals are transmitted on the same radio frequency and said transmit spatial processing means determines said transmit spatial signatures by calculating them directly from said receive spatial signatures.

26. The wireless system as defined by claim 14 wherein said transmit spatial processing means determines said transmit spatial signatures using the known location and directivity of said antenna elements and the known location of said plurality of remote terminals.

27. A wireless system including at least one base station for transmitting to a plurality of remote terminals using a common downlink channel, said system comprising:

transmission means at said at least one base station including a plurality of transmit antenna elements and transmitters for transmitting multiplexed downlink signals to said plurality of remote terminals,

transmit spatial processing means for determining transmit spatial signatures for said plurality of remote terminals, and

spatial multiplexing means using said transmit spatial signatures and downlink signals to produce said multiplexed downlink signals,

whereby said at least one base station can transmit said downlink signals to said plurality of remote terminals simultaneously on a common downlink channel.

28. The wireless system as defined by claim 27 wherein said common downlink channel is one of a plurality of downlink channels and wherein said transmit spatial processing means comprises:

an active remote terminal list comprising a list of remote terminals assigned to at least one the channels of said plurality of downlink channels,

a spatial signature list comprising a transmit spatial signature for each remote terminal of said plurality of remote terminals and each channel of said plurality of downlink channels,

transmit spatial signature determining means for determining said transmit spatial signatures, and

a transmit channel selector using said active remote terminal list and said spatial signature list to determine assignments of each remote terminal in said active remote terminal list to at least one of the channels of said plurality of downlink channels.

29. The wireless system as defined by claim 28 wherein said transmit spatial processing means further comprises:

a transmit spatial weight processor for calculating spatial multiplexing weights for each of the terminals in said active remote terminal list to which a downlink channel is assigned and each channel of said plurality of downlink channels assigned to at least one of the terminals in said active remote terminal list, said spatial multiplexing weights being utilized by said spatial multiplexing means to produce said multiplexed downlink signals.

30. The wireless system as defined by claim 27 wherein said at least one base station is one of a plurality of base stations, said common downlink channel is one of a plurality of downlink channels, said transmit spatial processing means is one 5 of a plurality of transmit spatial processing means, each base station in said plurality of base stations having a corresponding transmit spatial processing means in said plurality of transmit spatial processing means, each transmit spatial processing means in said plurality of transmit spatial processing means comprising:

an active remote terminal list comprising a list of remote terminals assigned to at least one the channels of said plurality of downlink channels,

a spatial signature list comprising a transmit spatial signature for each remote terminal of said plurality of remote terminals and each channel of said plurality of downlink channels,

transmit spatial signature determining means for determining said transmit spatial signatures, and

a transmit spatial weight processor for calculating spatial multiplexing weights for each of the terminals in said active remote terminal list to which a downlink channel is assigned and each channel of said plurality of downlink channels assigned to at least one of the terminals in said active remote terminal list, said spatial multiplexing weights being utilized by said spatial multiplexing means to produce said multiplexed downlink signals,

said system further comprising;

joint channel selector means for jointly determining assignments of each remote terminal in each said active remote terminal list to at least one of the channels of said plurality of down channels and to at least one of the base stations of said plurality of base stations, and

communication means for communicating said assignments between each base station in said plurality of base stations and said joint channel selector means.

31. The wireless system as defined by claim 27 wherein said spatial multiplexing means determines spatial multiplexing weights for said common downlink channel as the rows of a matrix W_tx as follows:

space="preserve" listing-type="equation">W.sub.tx =S.sub.b (A.sub.rb A.sup.*.sub.rb).sup.-1 A.sub.rb

where ()^* denotes the complex conjugate transpose of a matrix, S_b is the diagonal matrix of amplitudes of said downlink signals, and A_rb is a multiplexing spatial signature matrix whose rows are said transmit spatial signatures for said plurality of remote terminals and said common downlink channel, and said spatial multiplexing means utilizes said spatial multiplexing weights to produce said multiplexed downlink signals.

32. The wireless system as defined by claim 27 wherein said system includes a transponder co-located with each remote terminal of said plurality of remote terminals and wherein said transmit spatial processing means determines said transmit spatial signatures using signals transponded from at least one of the transponders.

33. The wireless system as defined by claim 27 wherein each remote terminal in said plurality of remote terminals includes a transponder, and wherein said transmit spatial processing means determines said transmit spatial signatures using signals transponded from at least one of the transponders.

34. The wireless system as defined by claim 27 wherein said downlink signals have predetermined modulation format parameters, and said transmit spatial signatures are determined by the corresponding terminals in said plurality of remote terminals using the predetermined modulation format parameters of said downlink signals.

35. The wireless system as defined by claim 27 wherein said transmit spatial processing means determines said transmit spatial signatures using the known location and directivity of said antenna elements and the known location of said plurality of remote terminals.