Systems and methods to enhance spatial diversity in distributed input distributed output wireless systems

• US 10,727,907 B2
• Filed: 01/21/2019
• Issued: 07/28/2020
• Est. Priority Date: 07/30/2004
• Status: Expired due to Term

• Current Assignee: Rearden, LLC
• Original Assignee: Rearden, LLC
• Inventors: Forenza, Antonio, Pitman, Timothy Anders, Jirasutavasuntorn, Benyavut, Andrzejewski, Robert J., Perlman, Stephen G.
• Primary Examiner(s): Cattungal, Ajay
• Application Number:
  US16/253,028
• Publication Number:
  US 20190158153A1
• Time in Patent Office: 554 Days
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04B 7/0465 taking power constraints at power amplifier or emission constraints, e.g. constant modulus, into account
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04B 7/0691 using subgroups of transmit antennas

Abstract

Systems and methods are described for enhancing the channel spatial diversity in a multiple antenna system (MAS) with multi-user (MU) transmissions (“MU-MAS”), by exploiting channel selectivity indicators. The proposed methods are: i) antenna selection; ii) user selection; iii) transmit power balancing. All three methods, or any combination of those, are shown to provide significant performance gains in DIDO systems in practical propagation scenarios.

Claims

1. A method implemented within a wireless power transmission system comprised of a plurality of wireless client devices, a base station, and a plurality of distributed antennas communicatively coupled to the base station comprising:

simultaneously transmitting pre-coded radio signals from the plurality of distributed antennas, the pre-coding creating deliberate radio frequency interference comprising a controlled constructive and destructive interference of radio frequency (RF) waveforms so as to enable wireless power reception upon each receiving antenna and resulting in a simultaneous plurality of non-interfering channels within a common frequency between the plurality of distributed antennas and the plurality of wireless client devices.

2. The method as in claim 1 further comprising:

estimating channel state information (CSI) at each of the plurality of wireless client devices; and

precoding data streams using the CSI prior to transmission, the precoding causing the channels to be non-interfering channels.

3. The method as in claim 2 wherein estimating CSI further comprises:

transmitting a training signal to each of the plurality of wireless client devices, the training signal being demodulated by each of the wireless client devices to estimate the CSI.

4. The method as in claim 2 wherein precoding data streams further comprises:

computing a plurality of precoding weights using the CSI received from each of the plurality of wireless client devices, each of the precoding weights associated with a non-interfering channel with a particular wireless client device.

5. The method as in claim 2 further comprising:

receiving a request from a wireless client device for network content;

forwarding the request over a data network to a server having the requested network content stored thereon;

receiving a response from the server containing the requested content;

precoding a data stream containing the content using the CSI prior to transmission over the wireless transmission system.

6. The method as in claim 2 wherein precoding further comprises adjusting relative phase and amplitude of each of the data streams to cause the channels to be non-interfering channels.

7. The method as in claim 1 wherein the plurality of distributed antennas are communicatively coupled to the base station over a high speed base station network (BSN) comprising of at least one fiber optic communication link.

8. The method as in claim 1 further comprising:

estimating channel state information (CSI) at each of the plurality of wireless client devices; and

precoding data streams using the CSI prior to transmission to generate a precoded baseband data streams; and

modulating the precoded baseband data streams at a specified carrier frequency prior to transmission over each of the distributed antennas.

9. The method as in claim 8 wherein each individual data stream is transmitted over a base station network (BSN) to each distributed antenna and modulated at each antenna prior to transmission.

10. The method as in claim 8 wherein each individual data stream is modulated at a base transceiver station (BTS) to generate a modulated data stream, and the modulated data stream is transmitted over the base station network (BSN) to each distributed antenna.

11. The method as in claim 1 further comprising:

performing time and frequency synchronization of each of the distributed antennas.

12. The method as in claim 11 wherein performing time and frequency synchronization further comprises:

introducing artificial delays in signal propagation over a network over which each of the distributed antennas are connected.

13. The method as in claim 11 further comprising:

using GPS disciplined oscillators (GPSDO) to perform the time and frequency synchronization.

14. The method as in claim 11 further comprising:

utilizing a 60 Hz power signal from a power line to perform the time and frequency synchronization.

15. The method as in claim 11 further comprising:

using an external clock reference to perform the time and frequency synchronization.

16. The method as in claim 1 further comprising:

estimating channel state information (CSI) at the base transceiver station (BTS) by exploiting uplink/downlink channel reciprocity; and

precoding data streams using the CSI prior to transmission, the precoding causing the channels to be non-interfering channels.

17. The method as in claim 16 wherein estimating CSI further comprises:

transmitting a training signal from each of the plurality of wireless client devices to the BTSs through each of the plurality of distributed antennas, the training signal being demodulated by the BTS to estimate the CSI.

18. A wireless power transmission system comprising:

a plurality of wireless client devices;

one or more base transceiver stations (BTSs);

a plurality of distributed antennas communicatively coupled to the BTSs over a base station network (BSN), wherein the BTSs precode RF waveforms for simultaneous transmission from each of the distributed antennas to the plurality of wireless client devices, the precoding creating deliberate radio frequency interference comprising a controlled constructive and destructive interference of RF waveforms so as to enable wireless power reception upon each receiving antenna and resulting in a simultaneous plurality of non-interfering channels within a common frequency between the plurality of distributed antennas and the plurality of wireless client devices.

19. The system as in claim 18 wherein the wireless client devices estimate channel state information (CSI) for the communication channels between the distributed antennas and each of the wireless client devices and wherein the BTSs precode the data streams using the CSI prior to transmission, the precoding causing the channels to be non-interfering channels.

20. The system as in claim 19 wherein the BTSs transmit a training signal to each of the plurality of wireless client devices from the distributed antennas, the training signal being demodulated by each of the wireless client devices to estimate the CSI.

21. The system as in claim 19 wherein to precode the data streams the BTS computes a plurality of precoding weights using the CSI received from each of the plurality of wireless client devices, each of the precoding weights associated with a communication channel with a particular wireless client device.

22. The system as in claim 19 wherein a BTS receives a request from a wireless client device for network content, forwards the request over a data network to a server having the requested network content stored thereon, receives a response from the server containing the requested content, and precodes a data stream containing the content using the CSI prior to transmission from the distributed antennas.

23. The system as in claim 19 wherein the BSN comprises of at least one high speed fiber optic communication link.

24. The system as in claim 23 further comprising:

an external clock reference coupled to the BTSs and/or the distributed antennas for performing the time and frequency synchronization.

25. The system as in claim 19 wherein the BTSs and/or distributed antennas perform time and frequency synchronization of each of the precoded data streams prior to transmission.

26. The system as in claim 19 wherein precoding further comprises adjusting relative phase and amplitude of each of the data streams to cause the channels to be non-interfering channels.

27. The system as in claim 18 wherein the wireless client devices estimate channel state information (CSI) for the communication channels between the distributed antennas and each of the wireless client devices and wherein the BTSs precode data streams using the CSI to generate precoded baseband data streams and transmit the precoded baseband data streams to the distributed antennas over the BSN, each of the distributed antennas having a transceiver for modulating the precoded baseband data streams at a specified carrier frequency prior to transmission.

28. The system as in claim 27 wherein performing time and frequency synchronization further comprises introducing artificial delays in signal propagation over the BSN.

29. The system as in claim 27 further comprising:

GPS disciplined oscillators (GPSDO) configured at the BTSs and/or distributed antennas for performing time and frequency synchronization.

30. The system as in claim 27 further comprising:

a power line providing a 60 Hz power signal to the BTSs and/or the distributed antennas to perform the time and frequency synchronization.

31. The system as in claim 18 wherein the wireless client devices estimate channel state information (CSI) for the communication channels between the distributed antennas and each of the wireless client devices and wherein the BTSs precode data streams using the CSI to generate precoded baseband data streams and modulate the precoded baseband data streams at a specified carrier frequency to generate modulated precoded data streams, and transmit the modulated precoded data streams to the distributed antennas over the BSN.

32. The system as in claim 18 wherein the base station estimates channel state information (CSI) for the communication channels between the wireless client devices and each of the distributed antennas and wherein the BTS precodes the data streams using the CSI prior to transmission, the precoding causing the channels to be non-interfering channels.

33. The system as in claim 32 wherein the client devices transmit a training signal to the BTS through each of the plurality of distributed antennas, the training signal being demodulated by the BTS to estimate the CSI.