Full duplex wireless transmission with self-interference cancellation

• US 10,742,388 B2
• Filed: 07/18/2017
• Issued: 08/11/2020
• Est. Priority Date: 05/13/2012
• Status: Active Grant

• Current Assignee: Amir Keyvan Khandani
• Original Assignee: Amir Keyvan Khandani
• Inventors: Khandani, Amir Keyvan
• Primary Examiner(s): Acolatse, Kodzovi
• Assistant Examiner(s): Ajid, Abdeltif
• Application Number:
  US15/653,384
• Publication Number:
  US 20170339569A1
• Time in Patent Office: 1,120 Days
• CPC Class Codes: H04B 1/123 using adaptive balancing or compensation means adaptive filter circuits and algorithms H03H
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04B 7/026 Co-operative diversity, e.g. using fixed or mobile stations as relays
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0478 Special codebook structures directed to feedback optimisation
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04B 7/0669 using different channel coding between antennas space-time coding H04L1/0618
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04L 1/18 Automatic repetition systems, e.g. Van Duuren systems
• CPC Class Codes: H04L 1/1825 Adaptation of specific ARQ protocol parameters according to transmission conditions
• CPC Class Codes: H04L 1/1896 ARQ related signaling
• CPC Class Codes: H04L 2001/0097 Relays
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04W 12/04 Key management, e.g. using generic bootstrapping architecture [GBA]
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks

Abstract

Two-way (full-duplex) wireless communications. Various embodiments measure interference channels and provide for interference cancellation in both analog and digital domains to mitigate self-interference. The system supports multiple clients wherein new clients can join the network asynchronously, and also supports Multiple-Input Multiple-Output (MIMO) antennas.

Claims

1. A method comprising:

in a first wireless communication node of a communication network, establishing with a plurality of clients full-duplex wireless links with at least partial overlap in time and frequency, the full-duplex wireless links comprising an uplink data channel, an uplink control channel, a downlink data channel, and a downlink control channel;

at the first wireless communication node, receiving incoming control channel communications over the uplink control channel while communicating with at least one first client over the downlink data channel;

at the first wireless communication node, transmitting downlink control channel communications over the downlink control channel while communicating with the at least one first client over the uplink data channel;

at the first wireless communication node, receiving over the uplink control channel the incoming control channel communications that include a request-to-join signal from a second client to join the communication network while the communication node is maintaining the full-duplex wireless links with the at least one first client, wherein the second client is an asynchronous client that requests to join the communication network without prior timing or frequency coordination; and

responsive to a receipt of the request-to-join signal from the second client over the uplink control channel, performing self-interference cancellation at the first wireless communication node to at least partially cancel (i) interference between the downlink control channel and the uplink data channel, and (ii) interference between the downlink data channel and the uplink control channel, wherein performing the self-interference cancellation includes performing at least a first stage of baseband self-interference cancellation to detect the request-to-join signal from the second client, wherein the first stage of baseband self-interference cancellation is performed in a time domain, and wherein the first stage of baseband self-interference cancellation is performed asynchronously with the incoming control channel communications including the request-to-join signal from the second client.

2. The method of claim 1, wherein receiving the incoming control channel communications over the uplink control channel while communicating with the at least one first client over the downlink data channel comprises continually listening to detect a valid incoming uplink control signal, the valid incoming uplink control signal including the request-to-join signal from the second client, while communicating with the at least one first client over the downlink data channel.

3. The method of claim 1, further comprising:

at the first wireless communication node, following the receipt of the request-to-join signal from the second client for active association with the communication network, performing synchronization, bandwidth allocation and scheduling between the first wireless communication node and the second client; and

after the synchronization, the bandwidth allocation and the scheduling, admitting the second client to the communication network.

4. The method of claim 1, wherein the first stage of baseband self-interference cancellation uses a filter in the time domain, the filter operating synchronously with transmissions from the first wireless communication node and wherein performing the first stage of baseband self-interference cancellation comprises filtering an outgoing baseband signal and subtracting the filtered outgoing baseband signal from an incoming baseband signal in the time domain, the method further comprising:

performing a second stage of baseband self-interference cancellation using an algorithmic base-band detection, wherein the algorithmic baseband detection is performed synchronously with signals transmitted from the first wireless communication node and signals received at the first wireless communication node.

5. The method of claim 4, further comprising:

measuring a baseband channel including effects of the first stage of baseband self-interference cancellation; and

obtaining weighting values for the second stage of baseband self-interference cancellation based on the measuring.

6. The method of claim 4, further comprising:

determining coefficients of the filter.

7. The method of claim 6, wherein determining the coefficients of the filter includes:

computing filter coefficients in a frequency domain; and

converting the filter coefficients into the time domain.

8. The method of claim 1, further comprising:

in the first wireless communication node, performing one or more of distributed modulation, collaborative resource allocation, scheduling and quality of service management to enable collaboration with at least a second wireless communication node.

9. The method of claim 1, wherein at least one of the uplink control channel or the downlink control channel is configured to carry one or more synchronization pilot signals, to coordinate retransmissions according to automatic repeat requests (ARQs), to provide feedback of channel status, and to provide feedback of received signal data.

10. The method of claim 1, further comprising:

in the first wireless communication node, broadcasting a common pilot signal via the downlink control channel to at least a second wireless communication node, the common pilot signal enabling joint detection.

11. The method of claim 1, wherein the first wireless communication node comprises a base station, and wherein the communication network comprises an Orthogonal Frequency Division Multiple Access (OFDMA) communication network.

14. The method of claim 10, wherein the common pilot signal enables joint detection in one or more of a multiple access channel or an interference channel.

15. The method of claim 10, wherein the common pilot signal is broadcast periodically to enable one or more clients to measure a state of the first wireless communication node.

12. A method comprising:

in a first wireless communication node of a communication network, establishing with a plurality of clients full-duplex wireless links with at least partial overlap in time and frequency, the full-duplex wireless links comprising an uplink data channel, an uplink control channel, a downlink data channel, and a downlink control channel, wherein the first wireless communication node is a MIMO communication node having a plurality of receive chains;

at the first wireless communication node, receiving incoming control channel communications over the uplink control channel while communicating with at least one client over the downlink data channel;

at the first wireless communication node, transmitting downlink control channel communications over the downlink control channel while communicating with the at least one client over the uplink data channel; and

performing self-interference cancellation at the first wireless communication node to at least partially cancel (i) interference between the downlink control channel and the uplink data channel, and (ii) interference between the downlink data channel and the uplink control channel, wherein performing the self-interference cancellation includes;

performing, in each of the plurality of receive chains, a first stage of baseband self-interference cancellation asynchronously with transmissions from the plurality of clients, wherein performing the first stage of baseband self-interference cancellation includes subtracting a first linear combination of baseband transmit signals; and

performing, in each of the plurality of receive chains, a second stage of baseband self-interference cancellation synchronously with signals received at the first wireless communication node, wherein performing the second stage of baseband self-interference cancellation includes subtracting a second linear combination of baseband transmit signals.

13. The method of claim 12, wherein the first wireless communication node comprises a plurality of receive antennas configured to improve a signal-to-noise ratio of the uplink control channel through diversity.

16. A method comprising:

in a first wireless communication node of an Orthogonal Frequency Division Multiple Access (OFDMA) communication network, establishing with a plurality of clients full-duplex wireless links with at least partial overlap in time and frequency, the full-duplex wireless links comprising an uplink data channel, an uplink control channel, a downlink data channel, and a downlink control channel;

at the first wireless communication node, receiving incoming control channel communications over the uplink control channel while communicating with at least one first client over the downlink data channel;

at the first wireless communication node, transmitting downlink control channel communications over the downlink control channel while communicating with the at least one first client over the uplink data channel;

at the first wireless communication node, receiving over the uplink control channel the incoming control channel communications that include a request-to-join signal from a second client to join the communication network while the communication node is maintaining the full-duplex wireless links with the at least one first client, wherein the second client is an asynchronous client that requests to join the communication network without prior timing or frequency coordination; and

responsive to a receipt of the request-to-join signal from the second client over the uplink control channel, performing self-interference cancellation at the first wireless communication node to at least partially cancel (i) interference between the downlink control channel and the uplink data channel, and (ii) interference between the downlink data channel and the uplink control channel, wherein performing the self-interference cancellation includes;

performing a first stage of baseband self-interference cancellation to detect the request-to-join signal from the second client, wherein the first stage of baseband self-interference cancellation is performed in a time domain, and wherein the first stage of baseband self-interference cancellation is performed asynchronously with the incoming control channel communications;

performing a second stage of baseband self-interference cancellation, wherein the second stage of baseband self-interference cancellation is performed in an orthogonal frequency division multiplexed (OFDM) domain, and wherein the second stage of baseband self-interference cancellation is performed synchronously with the incoming control channel communications; and

performing a third stage of baseband self-interference cancellation, wherein the third stage of baseband self-interference cancellation is performed in the time domain, and wherein the third stage of baseband self-interference cancellation performs compensation for signal clipping.

17. The method of claim 16, wherein the second stage of baseband self-interference cancellation further performs equalization in the OFDM domain.

18. The method of claim 16, wherein the third stage of baseband self-interference cancellation further performs compensation for an analog-to-digital residual signal in the time domain.

19. The method of claim 16, wherein the request-to-join signal from the second client includes a plurality of periods of a periodic sequence to allow for detection of the request-to-join signal at the first wireless communication node.

20. The method of claim 16, wherein the first stage of baseband self-interference cancellation produces a wake-up signal.

21. The method of claim 16, wherein the first wireless communication node comprises a base station.