System and method for distributed input-distributed output wireless communications

• US 20060023803A1
• Filed: 07/30/2004
• Published: 02/02/2006
• Est. Priority Date: 07/30/2004
• Status: Active Grant

• Current Assignee: Rearden, LLC
• Original Assignee: Rearden, LLC
• Inventors: Perlman, Stephen G., Cotter, Tim
• Granted Patent: US 7,418,053 B2
• Time in Patent Office: Days
• US Class Current: 375/267
• CPC Class Codes: H04B 7/0684 using different training sequences per antenna
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 2025/03414 Multicarrier
• CPC Class Codes: H04L 2025/0377 during the reception of training signals
• CPC Class Codes: H04L 2025/03802 Signalling on the reverse channel
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04L 25/03891 Spatial equalizers MIMO diversity systems H04B7/0413

Abstract

A method is described comprising: transmitting a training signal from each antenna of a base station to each of a plurality of client devices, each of the client devices analyzing each training signal to generate channel characterization data, and transmitting the channel characterization data back to the base station; storing the channel characterization data for each of the plurality of client devices; receiving data to be transmitted to each of the client devices; and precoding the data using the channel characterization data associated with each respective client device to generate precoded data signals for each antenna of the base station; and transmitting the precoded data signals through each antenna of the base station to each respective client device.

Claims

1. A method comprising:

transmitting a training signal from each antenna of a base station to each of a plurality of client devices, each of the client devices analyzing each training signal to generate channel characterization data, and transmitting the channel characterization data back to the base station;

storing the channel characterization data for each of the plurality of client devices;

receiving data to be transmitted to each of the client devices; and

preceding the data using the channel characterization data associated with each respective client device to generate precoded data signals for each antenna of the base station; and

transmitting the precoded data signals through each antenna of the base station to each respective client device.

2. The method of claim 1, further comprising:

transmitting a training signal through each antenna of the base station to each client device;

receiving channel characterization data for each client device, the channel characterization data for each client device having been generated by each client device having independently processed and characterized the training signal from each antenna of the base station; and

storing the channel characterization data for each client device.

3. The method of claim 2, further comprising:

periodically sending a new training signal through each antenna of the base station to each client device; and

receiving new channel characterization data for each client device, the channel characterization data for each client device having been generated by each client device having independently processed and characterized the new training signal from each antenna of the base station; and

storing the new channel characterization data for each client device.

4. The method of claim 3, wherein the new training signal is interleaved within precoded data signals.

5. The method of claim 1, further comprising:

receiving a training signal through each antenna of the base station from each client device;

characterizing the training signals to generate the channel characterization data, the channel characterization data associated with each client device and each antenna of the base station; and

storing the channel characterization data.

6. The method of claim 5, further comprising:

requesting the training signal from each client device.

7. The method of claim 5, further comprising:

continuously receiving a new training signal from each client device.

8. The method of claim 1, wherein transmitting each respective precoded data signal comprises:

a first transmission to a first selected group within the plurality of client devices; and

a second transmission to a second selected group within the plurality of client devices, the first and second selected group defined such as to allocate bandwidth in a desired fashion.

9. The method of claim 8, wherein the desired fashion is any combination selected from the group consisting of allocating bandwidth evenly, allocating bandwidth according to priority, allocating bandwidth based on a current load required by a client device, and allocating bandwidth to avoid multiple client devices in close proximity to each other.

10. The method of claim 1, wherein the base station communicates with two client devices concurrently using multiplexing techniques.

11. The method of claim 1, wherein a client device has multiple antennas, each antenna treated as a separate client device.

12. The method of claim 1, further comprising:

routing the input data into separate bit streams to respective antennas of the base station, each separate bit stream intended for a respective client device;

storing the channel characterization data as a channel characterization matrix; and

multiplying each separate bit stream by the inverse of the channel characterization matrix to generate the precoded data signals.

13. A method comprising:

receiving precoded data signals at a client device, each precoded data signal transmitted from a respective antenna of a plurality of antennas of a base station to each of a plurality of client devices, each precoded data signal based on input data and channel characterization data associated with each client device and each respective antenna of the base station.

14. The method of claim 13, further comprising:

receiving training signals from each of the plurality of antennas of the base station;

processing the training signals;

characterizing the training signals to generate the channel characterization data for the client device;

storing the channel characterization data for the client device;

transmitting the channel characterization data for the client device to each antenna of the base station, the base station generating the respective precoded data signals using the channel characterization data for the device.

15. The method of claim 14, wherein the client device has a second antenna, the second antenna being treated as a separate client device receiving respective precoded data signals and training signals.

16. The method of claim 13, further comprising:

transmitting a training signal to the base station, the base station processing and characterizing the training signal to generate the channel characterization data.

17. A system comprising:

a plurality of client devices;

a base station; and

a plurality of antennas of the base station, wherein each antenna of the base station transmits a respective precoded data signal to each client device, the respective precoded data signal generated by precoding input data using channel characterization data associated with each respective client device and each respective antenna of the base station.

18. The system of claim 17, wherein the channel characterization data is generated by each client device having independently processed and characterized a training signal transmitted by each antenna of the base station to each client device.

19. The system of claim 17, wherein the channel characterization data is generated by the base station having processed and characterized a training signal transmitted from each client device to each antenna of the base station.

20. The system of claim 17, wherein synchronization techniques are employed to ensure less than a certain number of transmissions and receptions at a given time, such as to not exceed total channel bandwidth.