Wireless Communications System That Supports Multiple Modes Of Operation

• US 20100046429A1
• Filed: 07/02/2009
• Published: 02/25/2010
• Est. Priority Date: 09/01/2000
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Arogyaswami J. Paulraj, Peroor K. Sebastian, Rajeev Krishnamoorthy, Robert W. Heath Jr
• Inventors: Heath, Robert W. JR., Paulraj, Arogyaswami J., Krishnamoorthy, Rajeev, Sebastian, Peroor K.
• Granted Patent: US 8,345,637 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• 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

1-51. -51. (canceled)

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

mode determination logic, in communication with the base transceiver station and the subscriber unit, capable of determining, 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, the mode determination logic comprising;

comparator logic capable of comparing a delay spread measure for the received signal to a delay spread threshold; and

a selector capable of selecting a spatial multiplexing operational mode for transmission of the subscriber datastream if the delay spread measure does not exceed the delay spread threshold and capable of a selecting non-spatial multiplexing operational mode if the delay spread measure exceeds the delay spread threshold.

53. The wireless communications system according to claim 52, wherein the base transceiver station and the subscriber unit are capable of utilizing a multiple access protocol to transmit the subscriber datastream, and

wherein the multiple access protocol comprises a code-division multiple access protocol, a frequency-division multiple access protocol, a time-division multiple access protocol, a space-division multiple access protocol, an orthogonal frequency division multiple access protocol, an orthogonal division multiple access protocol, or a quasi-orthogonal division multiple access protocol, or a combination thereof.

54. The wireless communications system according to claim 52, wherein operational mode information is communicated between the base transceiver station and the subscriber unit over a control channel.

55. The wireless communications system according to claim 52, wherein the mode determination logic comprises an input capable of receiving system specifications related to a signal receive capability of at least one of the base transceiver station and the subscriber unit.

56. The wireless communications system according to claim 52, wherein the mode determination logic comprises an input capable of receiving system specifications related to a signal transmit capability of at least one of the base transceiver station and the subscribe unit.

57. The wireless communications system according to claim 52, wherein the mode determination logic comprises logic capable of

determining if both the base transceiver station and the subscriber unit support spatial multiplexing;

and

capable of selecting a non-spatial multiplexing operational mode for transmission of the subscriber datastream if one of the base transceiver station and the subscriber unit does not support spatial multiplexing.

58. The wireless communications system according to claim 52, wherein non-spatial multiplexing transmission modes comprise single-carrier transmissions, multi-carrier transmissions, multi-code transmission, transmit diversity, or beamforming, or a combination thereof.

59. The wireless communications system according to claim 58, wherein transmit diversity comprises selection diversity, space-time coding, or maximum ratio combining, or a combination thereof.

60. The wireless communications system according to claim 52, wherein the mode determination logic resides within the subscriber unit.

61. The wireless communications system according to claim 52, wherein the mode determination logic resides within the base transceiver station.

62. A method for operating a wireless communications system, comprising:

receiving a signal transmission at one of a base transceiver station and a subscriber unit via the wireless communications system;

measuring a delay spread characteristic of the received signal transmission;

comparing the delay spread characteristic to a delay spread threshold; and

selecting a spatial multiplexing operational mode if the delay spread measure does not exceed the delay spread threshold and selecting a non-spatial multiplexing operational mode if the delay spread measure exceeds the delay spread threshold.

63. The method according to claim 62, wherein the base transceiver station and the subscriber unit utilize a multiple access protocol to transmit the subscriber datastream, and

wherein the multiple access protocol comprises a code-division multiple access protocol, a frequency-division multiple access protocol, a time-division multiple access protocol, a space-division multiple access protocol, an orthogonal frequency division multiple access protocol, an orthogonal division multiple access protocol, or a quasi-orthogonal division multiple access protocol, or a combination thereof.

64. The method according to claim 62, further comprising indicating the operational mode for subsequent transmissions in response to selecting the spatial multiplexing operational mode or the non-spatial multiplexing operational mode.

65. The method according to claim 64, further comprising using a dedicated control channel for indicating the operational mode.

66. The method according to claim 62, further comprising indicating a change in operation mode for subsequent transmissions in response to selecting the spatial multiplexing operational mode or selecting the non-spatial multiplexing operational mode.

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

a control channel capable of communicating whether a subscriber datastream should be transmitted between the base transceiver station and the subscriber unit utilizing a spatial multiplexing operational mode or a non-spatial multiplexing operational mode,

wherein the control channel is capable of being used to indicate a spatial multiplexing or a non-spatial multiplexing capability of one of the base transceiver station and/or the subscriber unit.

68. The wireless communication system according to claim 67, further comprising mode determination logic, in communication with the base transceiver station and the subscriber unit, capable of determining, in response to a received signal, if the subscriber datastream should be transmitted between the base transceiver station and the subscriber unit utilizing the spatial multiplexing operational mode or the non-spatial multiplexing operational mode.

69. The wireless communications system according to claim 68, wherein the mode determination logic comprises an input capable of receiving a measure of a transmission characteristic related to the received signal.

70. The wireless communications system according to claim 69, wherein the mode determination logic comprises logic capable of comparing the measured transmission characteristic to a transmission characteristic threshold;

and capable of selecting one of the spatial multiplexing operational mode and the non-spatial multiplexing operational mode in response to the comparison of the measured transmission characteristic to the transmission characteristic threshold.

71. The wireless communications system according to claim 70, wherein the transmission characteristic comprises a delay spread measure and the transmission characteristic threshold comprises a delay spread threshold, and

wherein the mode determination logic is further capable of selecting the spatial multiplexing operational mode if the delay spread measure does not exceed the delay spread threshold and capable of selecting a non-spatial multiplexing operational mode if the delay spread measure exceeds the delay spread threshold.