WIRELESS COMMUNICATIONS SYSTEM THAT SUPPORTS MULTIPLE MODES OF OPERATION

• US 20100142636A1
• Filed: 10/22/2009
• Published: 06/10/2010
• 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., Sebastian, Peroor K., Krishnamoorthy, Rajeev
• Granted Patent: US 8,428,037 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• 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 method for receiving data over a downlink channel in accordance with at least one of a plurality of transmission modes, the method comprising:

receiving at a mobile station a transmission mode indication to indicate one of the transmission modes, the transmission modes including single antenna, spatial multiplexing and transmit diversity modes;

configuring the mobile station to receive downlink signals in an orthogonal frequency division multiplexed (OFDM) protocol in accordance with the indicated transmission mode, the mobile station being configurable to receive downlink signals in accordance with at least two of the transmission modes; and

configuring the mobile station to receive downlink signals in accordance with another of the transmission modes based on information in a control channel.

2. The method of claim 1, wherein the indicated transmission mode is the spatial multiplexing mode.

3. The method of claim 2, wherein the another of the transmission modes is the single antenna mode.

4. The method of claim 2, wherein the another of the transmission modes is the transmit diversity mode.

5. The method of claim 1, wherein the indicated transmission mode is the single antenna mode.

6. The method of claim 5, wherein the another of the transmission modes is the spatial multiplexing mode.

7. The method of claim 1, wherein the indicated transmission mode is the transmit diversity mode.

8. The method of claim 7, wherein the another of the transmission modes is the spatial multiplexing mode.

9. A method for receiving data over a downlink channel in accordance with at least one of a plurality of transmission modes, the method comprising:

receiving at a subscriber unit a transmission mode indication to indicate one of the transmission modes, the transmission modes including a single antenna mode, a transmit diversity mode, and a spatial multiplexing mode;

configuring the subscriber unit to receive downlink signals in an orthogonal frequency division multiplexed (OFDM) protocol in accordance with the indicated transmission mode, the subscriber unit being configurable to receive downlink signals in accordance with at least two of the transmission modes; and

configuring the subscriber unit to receive downlink signals in accordance with another of the transmission modes.

10. The method of claim 9, wherein the indicated transmission mode is the spatial multiplexing mode.

11. The method of claim 10, wherein the another of the transmission modes is the single antenna mode.

12. The method of claim 10, wherein the another of the transmission modes is the transmit diversity mode.

13. The method of claim 9, wherein the indicated transmission mode is the single antenna mode.

14. The method of claim 13, wherein the another of the transmission modes is the spatial multiplexing mode.

15. The method of claim 9, wherein the indicated transmission mode is the transmit diversity mode.

16. The method of claim 15, wherein the another of the transmission modes is the spatial multiplexing mode.