Cooperative wireless networks

• US 9,042,333 B2
• Filed: 05/12/2014
• Issued: 05/26/2015
• Est. Priority Date: 05/14/2002
• Status: Expired due to Fees

• Current Assignee: Genghiscomm Holdings, LLC
• Original Assignee: Genghiscomm Holdings, LLC
• Inventors: Shattil, Steve
• Primary Examiner(s): CHOUDHRY, SAMINA F
• Application Number:
  US14/275,161
• Publication Number:
  US 20140241296A1
• Time in Patent Office: 379 Days
• Field of Search: 370/329, 370/338, 370/341
• US Class Current: 370/329
• CPC Class Codes: H04B 1/0003 Software-defined radio [SDR] systems, i.e. systems wherein components typically implemented in hardware, e.g. filters or modulators/demodulators, are implented using software, e.g. by involving an AD or DA conversion stage such that at least part of the signal processing is performed in the digital domain digital baseband systems H04L25/00; digital modulation/demodulation H04L27/00; CDMA H04B1/707; TDMA H04B7/2643; image transmission H04N5/00
• 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 7/026 Co-operative diversity, e.g. using fixed or mobile stations as relays
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/0456 Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
• CPC Class Codes: H04B 7/0697 using spatial multiplexing
• CPC Class Codes: H04J 13/0003 Code application, i.e. aspects relating to how codes are applied to form multiplexed channels
• CPC Class Codes: H04J 13/004 Orthogonal
• CPC Class Codes: H04J 13/12 Generation of orthogonal codes
• CPC Class Codes: H04L 27/01 Equalisers baseband equalizers at the transmitter end H04L25/03343; in analogue transmission systems H04B3/04, H04B7/005
• CPC Class Codes: H04L 27/148 using filters, including PLL-type filters
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 27/2614 Peak power aspects
• CPC Class Codes: H04L 27/2636 with FFT or DFT modulators, e.g. standard single-carrier frequency-division multiple access [SC-FDMA] transmitter or DFT spread orthogonal frequency division multiplexing [DFT-SOFDM]
• CPC Class Codes: H04L 27/2646 using feedback from receiver for adjusting OFDM transmission parameters, e.g. transmission timing or guard interval length
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04L 27/26526 with inverse FFT [IFFT] or inverse DFT [IDFT] demodulators, e.g. standard single-carrier frequency-division multiple access [SC-FDMA] receiver or DFT spread orthogonal frequency division multiplexing [DFT-SOFDM]
• CPC Class Codes: H04L 27/26534 Pulse-shaped multi-carrier, i.e. not using rectangular window
• CPC Class Codes: H04L 45/24 Multipath
• CPC Class Codes: H04L 47/10 : Flow control; Congestion control
• CPC Class Codes: H04L 5/0007 : the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0021 : in which codes are applied as a frequency-domain sequences, e.g. MC-CDMA
• CPC Class Codes: H04L 5/0023 : Time-frequency-space
• CPC Class Codes: H04L 5/0035 : Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04L 5/0037 : Inter-user or inter-terminal allocation
• CPC Class Codes: H04L 5/0073 : Allocation arrangements that take into account other cell interferences for intercell interference mitigation or co-ordination in orthogonal multiplex systems H04J11/005
• CPC Class Codes: H04W 72/046 : the resource being in the space domain, e.g. beams
• CPC Class Codes: H04W 84/18 : Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

A cooperative multi-user multiple input, multiple output (MIMO) system coordinates spatially distributed transceiver stations for communicating with wireless client devices. The system comprises a network interface communicatively coupled to the transceiver stations via a backhaul network, which may comprise a wireless local area network. A MIMO processor pre-codes N_R original data streams to generate N_T subspace-coded data streams, wherein each subspace-coded data stream comprises a linear combination of at least some of the original data streams. N_T may denote a number of transmitting antennas, and N_R may denote a number of receiving antennas. A network controller conveys the subspace-coded data streams to the transceiver stations via the backhaul network and coordinates the simultaneous transmission of the subspace-coded data streams over wireless links to the wireless client devices. The pre-coding causes the transmissions to coherently combine at a first wireless client device to produce at least a first data stream while suppressing inter-user interference from at least a second data stream intended for at least a second wireless client device. The client devices and/or the transceiver stations may be selected based on channel state information and/or measured channel quality.

Claims

1. A cooperative multi-user multiple input, multiple output (MIMO) system, comprising:

at least one MIMO processor configured to pre-code a plurality of data streams to generate a plurality of subspace-coded data streams, each subspace-coded data stream comprising a linear combination constructed from a sum of a plurality of terms multiplied by coefficients, the plurality of terms comprising at least a subset plurality of the plurality of data streams, and the coefficients comprising MIMO subspace code values based on channel state information corresponding to channels between a plurality of spatially distributed transceiver stations and a plurality of wireless client devices;

a network interface communicatively coupled to the plurality of spatially distributed transceiver stations via a network; and

a network controller configured to send the subspace-coded data streams to the plurality of spatially distributed transceiver stations via the network, and coordinate the plurality of spatially distributed transceiver stations to simultaneously transmit the subspace-coded data streams over wireless links to each of the plurality of wireless client devices, the MIMO subspace code values providing for transmissions comprising a plurality of simultaneous non-interfering subspace channels within a common frequency, wherein first portions of transmissions received at a first wireless client device coherently combine to produce at least a first set of the plurality of data streams, and wherein at least second portions of the transmissions received at the first wireless client device combine to cancel at least a second set of the plurality of data streams intended for at least a second wireless client device.

2. The system recited in claim 1, wherein at least one of the plurality of wireless client devices comprises an antenna array, and the MIMO subspace code values are configured to produce deliberate radio frequency interference comprising a controlled constructive and destructive interference of transmitted waveforms so as to enable data reception of a different data stream upon each of a plurality of receiving antennas of the antenna array.

3. The system recited in claim 1, wherein the network comprises at least one of a local area network and a backhaul network.

4. The system recited in claim 1, wherein at least one of the plurality of spatially distributed transceiver stations comprises an antenna array, and the at least one MIMO processor provides for at least one of diversity transmission, spatial division multiple access, and long baseline interferometry for signals transmitted from the antenna array.

5. The system recited in claim 1, wherein at least one of the network controller and the at least one MIMO processor resides in at least one of the plurality of spatially distributed transceiver stations.

6. The system recited in claim 1, wherein the plurality of spatially distributed transceiver stations comprises at least one of a base transceiver station, a network access point, a network router, a gateway, a relay, and a client device.

7. The system recited in claim 1, wherein at least one of the network controller and the at least one MIMO processor is configured for employing at least one of antenna selection, selection of the plurality of spatially distributed network transceiver stations, and selection of the plurality of wireless client devices to enhance channel spatial diversity.

8. A method comprising:

generating channel estimates for wireless channels between a plurality of wireless client devices and a plurality of spatially distributed transceiver stations for producing channel state information;

employing at least one of link quality and the channel state information for selecting the plurality of wireless client devices to be served by the plurality of spatially distributed transceiver stations, and selecting, for at least one client device of the plurality of wireless client devices, a subset plurality of the plurality of spatially distributed transceiver stations to serve the at least one client device;

generating cooperative multiple input, multiple output (MIMO) subspace weights from the channel state information;

generating pre-coded data comprising a plurality of linear combinations, each linear combination comprising a sum of a plurality of terms multiplied by coefficients, wherein the terms comprise data values and the coefficients comprise the MIMO subspace weights; and

coordinating transmissions of the pre-coded data from at least the subset plurality of the plurality of spatially distributed transceiver stations to produce a plurality of non-interfering subspace channels in a common frequency, wherein first signal portions in transmissions received by a first wireless client device coherently combine to produce at least a first set of data streams, and second signal portions in the transmissions received by the first wireless client device combine to cancel at least a second set of data streams intended for at least a second wireless client device.

9. The method recited in claim 8, wherein generating channel estimates is performed by at least one of a set of devices, the set comprising at least some of the plurality of wireless client devices and at least some of the plurality of spatially distributed transceiver stations.

10. The method recited in claim 8, wherein the subspace weights comprise at least one of eigen-directions of a channel covariance matrix, singular value decomposition pre-coding, and pre-coding configured for cancelling known interference, including interference from a source other than the plurality of spatially distributed transceiver stations.

11. The method recited in claim 8, wherein generating channel estimates comprises receiving feedback from the plurality of wireless client devices, wherein the feedback comprises at least one of a performance indication of received signals, channel estimates, and a training sequence used to evaluate the channel.

12. The method recited in claim 8, further comprising, for at least one of the subspace channels, selecting at least one of modulation, coding, transmit power, OFDM subcarriers, network transceiver nodes, an antenna on a transceiver station, and a client device antenna based on at least one of the channel state information and link quality of the at least one subspace channel.

13. The method recited in claim 8, wherein generating pre-coded data provides for at least one of diversity transmission from a plurality of antennas of the plurality of spatially distributed transceiver stations and antenna selection in at least one transceiver station antenna array.

14. A non-transitory computer readable storage medium having computer readable code thereon, the medium comprising instructions for:

determining channel characterization data for channels between a plurality of spatially distributed transceiver stations and a plurality of wireless client devices to generate channel state information;

selecting a subset plurality of the wireless client devices to share a common frequency based on at least one of the channel state information and measured link quality;

computing a plurality of cooperative multiple input, multiple output (MIMO) subspace weights based on the channel characterization data;

pre-coding data using the MIMO subspace weights to generate pre-coded data signals, each of the pre-coded data signals comprising a linear combination constructed from a sum of a plurality of terms multiplied by coefficients, the plurality of terms comprising the data, and the coefficients comprising MIMO subspace weights that provide a plurality of simultaneous non-interfering subspace channels within the common frequency when the pre-coded data signals are transmitted by the plurality of spatially distributed transceiver stations to the subset plurality of wireless client devices; and

providing for transmitting the pre-coded data signals from each of the spatially distributed transceiver stations to each of the subset plurality of wireless client devices, wherein at least first portions of transmissions received by a first wireless client device from the plurality of spatially distributed transceiver stations coherently combine to produce at least a first set of data streams, and wherein at least second portions of the transmissions received by the first wireless client device combine to cancel at least a second set of data streams intended for at least one other wireless client device of the subset plurality.

15. The medium recited in claim 14, further comprising, for each wireless client device, selecting the plurality of spatially distributed transceiver stations based on at least one of channel state information and channel quality between the each wireless client device and each of the plurality of spatially distributed transceiver stations.

16. The medium recited in claim 14, wherein determining channel characterization data is performed by at least one of a set of devices, the set comprising the plurality of wireless client devices and the plurality of spatially distributed transceiver stations.

17. The medium recited in claim 14, wherein determining channel characterization data comprises receiving feedback from the plurality of wireless client devices, wherein the feedback comprises at least one of a performance indication of received signals, channel estimates, and a training sequence for evaluating the channel.

18. The medium recited in claim 14, wherein at least one of pre-coding and transmitting comprises performing at least one of antenna selection and diversity transmission in at least one transceiver station antenna array.

19. The medium recited in claim 14, wherein the MIMO subspace weights comprise at least one of eigen-directions of a channel covariance matrix, singular value decomposition pre-coding, and pre-coding configured for cancelling known interference, including interference from a source other than the plurality of spatially distributed transceiver stations.

20. The medium recited in claim 14, further comprising, for at least one subspace channel, selecting at least one of modulation, coding, transmit power, OFDM subcarriers, transceiver stations, an antenna on a transceiver station, and a wireless client device antenna based on at least one of channel state information and measured link quality of the at least one subspace channel.