System and method for distributed antenna wireless communications

• US 8,654,815 B1
• Filed: 12/03/2009
• Issued: 02/18/2014
• Est. Priority Date: 04/02/2004
• Status: Expired due to Term

• Current Assignee: Rearden, LLC
• Original Assignee: Rearden, LLC
• Inventors: Forenza, Antonio, Perlman, Stephen G.
• Primary Examiner(s): HA, DAC V
• Application Number:
  US12/630,627
• Time in Patent Office: 1,538 Days
• Field of Search: 375/141, 375/146, 375/219, 375/220, 375/222, 375/260, 375/267, 375/285, 375/296, 375/298, 375/299, 375/144, 370/319, 370/320, 370/342, 370/344, 370/441
• US Class Current: 375/141
• CPC Class Codes: H04B 7/022 Site diversity; Macro-diversity using two or more spaced independent antennas H04B7/04
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04B 7/0634 Antenna weights or vector/matrix coefficients
• CPC Class Codes: H04B 7/0684 using different training sequences per antenna
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/007 Unequal error protection for format H04L1/0078; for codes per se H03M13/35
• 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 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 25/03949 equalizer selection or adaptation based on feedback multiple signaling inclusive of a precoding command for adapting the transmitter H04L1/0031; feedback for transmit diversity systems H04B7/0619; selection of codebook or precoding matrix for MIMO diversity systems H04B7/0456
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition

Abstract

A system and method are described for distributed antenna wireless communications. For example, a method implemented within a wireless transmission system comprised of a plurality of wireless client devices and a plurality of distributed antennas is described comprising: computing channel state information (CSI) for wireless communication channels between the plurality of base distributed antennas and the wireless client devices; computing precoding weights from the channel state information; precoding data using the precoding weights prior to wireless transmission from the plurality of distributed antennas to the wireless client devices; and wirelessly transmitting the precoded data from the distributed antennas to each of the wireless client devices, wherein the precoding causes radio frequency interference between the plurality of base stations but simultaneously generating a plurality of non-interfering radio frequency user channels between the plurality of distributed antennas and the plurality of wireless client devices.

Claims

1. A method implemented within a wireless 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 RF waveforms so as to enable data 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 communication 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 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.

7. 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.

8. The method as in claim 7 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.

9. The method as in claim 7 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.

10. The method as in claim 1 further comprising:

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

11. The method as in claim 10 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.

12. The method as in claim 10 further comprising:

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

13. The method as in claim 10 further comprising:

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

14. The method as in claim 10 further comprising:

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

15. 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.

30. 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.

31. The method as in claim 30 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.

16. A wireless 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 data streams 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 data 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.

17. The system as in claim 16 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.

18. The system as in claim 17 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.

19. The system as in claim 17 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.

20. The system as in claim 17 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.

21. The system as in claim 17 wherein the BSN comprises of at least one high speed fiber optic communication link.

22. The system as in claim 16 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.

23. The system as in claim 16 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.

24. The system as in claim 17 wherein the BTSs and/or distributed antennas perform time and frequency synchronization of each of the precoded data streams prior to transmission.

25. The system as in claim 22 wherein performing time and frequency synchronization further comprises introducing artificial delays in signal propagation over the BSN.

26. The system as in claim 22 further comprising:

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

27. The system as in claim 22 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.

28. The system as in claim 21 further comprising:

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

29. The system as in claim 17 wherein precoding further comprises adjusting relative phase and amplitude of each of the data streams to cause the channels to be non-interfering channels.

32. The system as in claim 16 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.