Wireless communications system that supports multiple modes of operation

• US 7,586,873 B2
• Filed: 04/07/2005
• Issued: 09/08/2009
• Est. Priority Date: 09/01/2000
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Intel Corporation
• Inventors: Heath, Robert W. Jr., Paulraj, Arogyaswami J., Sebastian, Peroor K., Krishnamoorthy, Rajeev
• Primary Examiner(s): BLANTON, JOHN D
• Application Number:
  US11/101,813
• Publication Number:
  US 20050174981A1
• Time in Patent Office: 1,615 Days
• Field of Search: 370/342
• US Class Current: 370/329
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 48/18 Selecting a network or a communication service
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

A wireless communications adapts its mode of operation between spatial multiplexing and non-spatial multiplexing in response to transmission-specific variables. An embodiment of a wireless communications system for transmitting information between a base transceiver station and a subscriber unit includes mode determination logic. The mode determination logic is in communication with the base transceiver station and the subscriber unit. The mode determination logic determines, in response to a received signal, if a subscriber datastream should be transmitted between the base transceiver station and the subscriber unit utilizing spatial multiplexing or non-spatial multiplexing. In an embodiment, the mode determination logic has an input for receiving a measure of a transmission characteristic related to the received signal. In an embodiment, the mode determination logic includes logic for comparing the measured transmission characteristic to a transmission characteristic threshold and for selecting one of spatial multiplexing and non-spatial multiplexing in response to the comparison of the measured transmission characteristic to the transmission characteristic threshold. In an embodiment, the transmission characteristic includes at least one of delay spread, post-processing signal-to-noise ratio, cyclical redundancy check (CRC) failure, residual inter-symbol interference, mean square error, coherence time, and path loss. By adapting the mode of operation in response to transmission-specific variables, the use of spatial multiplexing can be discontinued in unfavorable conditions. Additionally, because the wireless communications system can adapt its mode of operation between spatial multiplexing and non-spatial multiplexing, the communications system is compatible with both subscriber units that support spatial multiplexing and subscriber units that do not support spatial multiplexing.

Claims

1. A wireless communications system for transmitting information between a base transceiver station and a subscriber unit, the wireless communications system comprising:

means for comparing a delay spread measure for a received signal to a delay spread threshold; and

means for determining, in response to a received signal, if a subscriber datastream should be transmitted between said base transceiver station and said subscriber unit utilizing spatial multiplexing or non-spatial multiplexing;

the means for determining selecting spatial multiplexing for transmission of said subscriber datastream if the delay spread measure is not above the delay spread threshold and selecting non-spatial multiplexing if the delay spread measure is above the delay spread threshold.

2. The wireless communications system of claim 1 wherein said determining means comprises means for receiving a measure of a transmission characteristic related to said received signal, and wherein the measure of the transmission characteristic related to said received signal comprises at least the delay spread measure of the received signal.

3. The wireless communications system of claim 1 wherein said base transceiver station and said subscriber unit utilize a multiple access protocol to transmit said subscriber datastream, wherein said multiple access protocol is selected from at least one of a group of multiple access protocols comprising:

code-division multiple access, frequency-division multiple access, time-division multiple access, space-division multiple access, orthogonal frequency division multiple access, wavelength division multiple access, wavelet division multiple access, orthogonal division multiple access, or quasi-orthogonal division multiple access, or combinations thereof.

4. The wireless communications system of claim 1 wherein the means for determining further generating mode determination information that is communicated between said base transceiver station and said subscriber unit over a control channel.

5. The wireless communications system of claim 1 wherein said determining means comprises means for receiving system specifications related to the signal receive capability of at least one of said base transceiver station or said subscriber unit, or combinations thereof.

6. The wireless communications system of claim 1 wherein said determining means comprises means for receiving system specifications related to the signal transmit capability of at least one of said base transceiver station or said subscriber unit, or combinations thereof.

7. The wireless communications system of claim 1 wherein said determining means comprises:

means for determining if both said base transceiver station and said subscriber unit support spatial multiplexing; and

wherein the determining means further selecting non-spatial multiplexing for transmission of said subscriber datastream if one of said base transceiver station or said subscriber unit, or combinations thereof, does not support spatial multiplexing.

8. The wireless communications system of claim 1 wherein non-spatial multiplexing transmission modes comprise single-carrier transmissions, multi-carrier transmissions, multi-code transmissions, transmit diversity, or beamforming, or combinations thereof.

9. The wireless communications system of claim 8 wherein transmit diversity comprises selection diversity, space-time coding, or maximum ratio combining, or combinations thereof.

10. The wireless communications system of claim 8 wherein said base transceiver station or said subscriber unit, or combinations thereof, are capable of transmitting said subscriber datastream in more than one of said non-spatial multiplexing transmission modes.

11. The wireless communications system of claim 1 wherein said determining means is disposed within said subscriber unit.

12. The wireless communications system of claim 1 wherein said determining means is disposed within said base transceiver station.