Spatial division multiple access wireless communication systems

• US 5,515,378 A
• Filed: 12/12/1991
• Issued: 05/07/1996
• Est. Priority Date: 12/12/1991
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: ArrayComm LLC (Ygomi LLC)
• Inventors: Roy, III, Richard H., Ottersten, Bjorn
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): Nguyen, Chau T.
• Application Number:
  US07/806,695
• Time in Patent Office: 1,608 Days
• Field of Search: 370/95.1, 370/95.3, 370/119, 342/386, 342/448, 342/442, 358/425, 358/133, 358/167, 455/60, 455/132, 455/137, 455/139, 455/272, 455/273, 455/33.2, 455/33.3, 359/183, 359/117, 359/154, 359/189, 375/295, 364/572, 364/574, 364/578, 364/581
• US Class Current: 370/334
• 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 17/309 Measuring or estimating channel quality parameters
• 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 7/0697 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
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 84/025 with acknowledge back capability

Abstract

A method and apparatus for increasing the capacity and quality of wireless communication between a plurality of remote users and a base station is disclosed. Using measurements from an array of receiving antennas at the base station, parameters of multiple signals transmitted to the base station from a plurality of users in the same channel are calculated and used to obtain the positions and velocities of the users. The locations and other related signal parameters are used to calculate appropriate spatial demultiplexing strategies, reconstructing the individual transmitted signals from the receiver measurements and reducing interference to acceptable levels. This heretofore unavailable location information is used in solving the hand-off problem. This information is also used to calculate an appropriate spatial multiplexing strategy for simultaneous transmission of signals to users in the same channel. This can be the same as or distinct from the aforementioned receive channel. In combination, the transmit and receive systems establish multiple full-duplex links in the same channel by directively receiving and transmitting signals at the base stations only. This invention can also be implemented at the mobile sites to improve signal quality and to establish point-to-point communication links between multiple mobile users. Furthermore, implementation of both transmit and receive functions at the base station is not required. A receive-only system base station will still improve received signal quality and therefore capacity in addition to mitigating the hand-off problem.

Claims

1. A wireless system including a base station for receiving uplink signals transmitted by users at different spatial locations comprising:

receiving means including a plurality of receiving antennas at said base station for detecting combinations of arriving signals from said users, said receiving means further comprising plural multichannel receivers for obtaining said combinations of arriving signals from said receiving antennas for plural uplink channels from said users, each multichannel receiver having one channel for each uplink channel;

processing means at said base station for processing said combinations of arriving signals, said processing means including means for determining a number of arriving signals in each of said uplink channels by employing statistical methods using eigenvalues of a covariance matrix calculated using said combinations of arriving signals,

means for obtaining said parameters of said arriving signals including directions of arrival of said arriving signals,

means for tracking user parameters including locations of said users from said parameters and said combinations of arriving signals, and

spatial demultiplexing means for obtaining estimates of each of said uplink signals from said combinations of arriving signals and said parameters of arriving signals and said user parameters.

2. The wireless system as defined by claim 1 wherein said spatial demultiplexing means for obtaining said estimates of said uplink signals comprises:

means for using said parameters of arriving signals and said user parameters and said combinations of arriving signals from said receiving antennas in each of said uplink channels for obtaining said arriving signals,

means for associating said arriving signals in each of said uplink channels with said users in each of said uplink channels, and

means for combining said arriving signals in each of said uplink channels associated with each of said users in each of said uplink channels to obtain said estimates of said uplink signals.

3. The wireless system as defined by claim 1 wherein said base station is one of a plurality of base stations, and further including

means for assigning each user to one of said uplink channels, and

means for selecting, at least one of said base stations for spatially demultiplexing said combinations of arriving signals to obtain transmitted uplink signals in said uplink channels.

4. A wireless system for communication of downlink signals from a base station in downlink channels to users at locations remote from said base station, said wireless system comprising:

spatial multiplexing means for combining downlink signals to be transmitted from said base station in downlink channels to said users, and

transmitting means having an input connected to said spatial multiplexing means for transmitting the combined downlink signals and including plural transmitting antennas and multichannel transmitters with one multichannel transmitter for each transmitting antenna and with one channel of each of said multichannel transmitters for each of said downlink channels,

whereby said downlink signals are transmitted to said users in a spatially selective manner.

5. A wireless system for communication of downlink signals from a base station to users at locations remote from said base station, said wireless system comprising:

spatial multiplexing means for combining downlink signals to be transmitted from said base station in downlink channels to said users, and

transmitting means having an input connected to said spatial multiplexing means for transmitting the combined downlink signals and including plural transmitting antennas and multichannel transmitters with one multichannel transmitter for each transmitting antenna and with one channel of each of said multichannel transmitters for each of said downlink channels,

whereby said downlink signals are transmitted to said users in a spatially selective manner and,

wherein said base station is one of a plurality of base stations, and wherein said spatial multiplexing means comprises;

means for selecting at least one base station from said plurality of base stations for transmission of each of said downlink signals to each user,

said spatial multiplexing means including means for combining said downlink signals for each of said downlink channels for each of said transmitting antennas at said selected at least one base station.

6. The wireless system as defined by claim 5 and further including:

means for assigning each of said users to a downlink channel.

7. A wireless system for full duplex communication of downlink signals and uplink signals between a base station and users physically remote from said base station, said wireless system comprising:

receiving means at said base station for detecting combinations of arriving signals from said users in said uplink channel and including a plurality of receiving antennas and multichannel receivers with on multichannel receiver for each of said receiving antennas, each channel of each of said multichannel receivers dedicated to an uplink channel,

processing means for processing said combinations of arriving signals in each uplink channel, said processing means comprising;

means for determining the number of arriving signals in each of said uplink channels by employing statistical methods using eigenvalues of a covariance matrix calculated using said combinations of arriving signals,

means for obtaining parameters of said arriving signals including directions of arrival of said arriving signals, and

means for tracking user parameters including locations of said users from said parameters and said combinations of arriving signals,

spatial demultiplexing means for obtaining estimates of the uplink signals in each uplink channel from said combinations of arriving signals and said parameters of arriving signals and said user parameters,

spatial multiplexing means using said parameters of arriving signals and said user parameters for combining downlink signals from said base station to said users in at least one downlink channel, and

transmitting means having an input connected to said spatial multiplexing means for transmitting the combined downlink signals and including a plurality of transmitting antennas and multichannel transmitters with one multichannel transmitter for each of said transmitting antennas, one channel of said multichannel transmitters dedicated to a downlink channel and to the spatial transmission of said downlink signals to said users in said at least one downlink channel,

whereby reception of multiple uplink signals in multiple uplink channels from said users and transmission of multiple downlink signals in multiple downlink channels to said users can occur simultaneously.

8. The wireless system as defined by claim 7 wherein said spatial demultiplexing means comprise:

means for using said parameters and said combinations of arriving signals from said receiving antennas in each of said uplink channels for reducing channel interference and noise,

means for associating said arriving signals in each of said uplink channels with said users in each of said uplink channels, and

means for combining said arriving signals in each of said uplink channels associated with each of said users in each of said uplink channels to obtain said estimates of said uplink signals.

9. The wireless system as defined by claim 7 wherein said base station is one of a plurality of base stations, and further including

means for selecting at least one base station from said plurality of base stations for transmission of each of said downlink signals to each user,

said spatial multiplexing means including means for combining said downlink signals for each of said downlink channels and for each of said transmitting antennas at said selected at least one base station.

10. The wireless system as defined by claim 7 wherein said base station is one of a plurality of base stations, and further including

means for assigning each of said users to an uplink channel, and

means for selecting at least one of said base stations for spatially demultiplexing said measurements to obtain said estimates of said uplink signals in said uplink channel.

11. The wireless system as defined by claim 7 wherein said base station is one of a plurality of base stations, and further including

means for assigning each of said users to a downlink channel, and

means for selecting at least one of said base stations for transmitting each of said downlink signals to each of said users in an assigned downlink channel.