System and Method for Training Signals for Full-Duplex Communications Systems

• US 20160233903A1
• Filed: 02/09/2015
• Published: 08/11/2016
• Est. Priority Date: 02/09/2015
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Wu, Huan, Hum, Eddy Shi-Ning
• Granted Patent: US 9,748,990 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 1/12 Neutralising, balancing, or compensation arrangements
• CPC Class Codes: H04B 15/00 Suppression or limitation of noise or interference by means associated with receiver H04B1/10
• CPC Class Codes: H04J 13/0062 Zadoff-Chu
• CPC Class Codes: H04L 25/0244 with inversion
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 27/26134 Pilot insertion in the transmitter chain, e.g. pilot overlapping with data, insertion in time or frequency domain
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/1461 Suppression of signals in the return path, i.e. bidirectional control circuits
• CPC Class Codes: H04L 5/16 Half-duplex systems; Simplex/duplex switching; Transmission of break signals non-automatically inverting the direction of transmission
• CPC Class Codes: H04L 69/14 Multichannel or multilink protocols
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers

Abstract

A method includes transmitting a training signal derived from a sequence, the training signal facilitates an estimation of a channel impulse response (CIR) for a communications channel between a transmit antenna of the device and a receive antenna of the device, estimating the CIR for the communications channel, and receiving signals corresponding to a first transmission at the receive antenna. The method also includes cancelling self-interference present in the received signals in accordance with the estimated CIR, the self-interference arising from a second transmission made by the transmit antenna of the device, thereby producing an interference canceled received signal, and processing the interference canceled received signal.

Claims

1. A method for operating a device configured to operate in a full-duplex mode, the method comprising:

transmitting, by the device, a training signal derived from a sequence, the training signal configured to facilitate an estimation of a channel impulse response (CIR) for a communications channel between a transmit antenna of the device and a receive antenna of the device;

estimating, by the device, the CIR for the communications channel;

receiving, by the device, signals corresponding to a first transmission at the receive antenna;

cancelling, by the device, self-interference present in the received signals in accordance with the estimated CIR, the self-interference arising from a second transmission made by the transmit antenna of the device, thereby producing an interference canceled received signal; and

processing, by the device, the interference canceled received signal.

2. The method of claim 1, wherein the sequence has a correlation matrix that is a scaled identity matrix.

3. The method of claim 1, wherein the cancelling comprises cancelling the self-interference present in the received signals in accordance with data associated with the second transmission.

4. The method of claim 1, wherein the sequence comprises a zero-correlation-zone (ZCZ) sequence.

5. The method of claim 1, wherein the training signal is derived from the sequence in accordance with a communications system requirement.

6. The method of claim 5, wherein the communications system requirement comprises at least one of:

a length of the sequence is equal to a desired symbol length N before a cyclic prefix is added, where N is an integer value;

a size of a sequence set that includes the sequence is at least equal to a number of transmit antennas of the device N_b; and

a sequence zone length is at least equal to a channel delay spread L_b which dictates a minimum sequence zone length for auto-correlations and cross-correlations of sequences in the sequence set.

7. The method of claim 5, wherein the training signal is derived from Zadoff-Chu sequences.

8. The method of claim 1, wherein the training signal is transmitted while the device is operating in a half-duplex mode.

9. The method of claim 1, wherein the training signal is transmitted in a special subframe comprising a downlink portion, a training portion, and an uplink portion.

10. The method of claim 9, wherein the training signal is transmitted in the training portion of the special subframe.

11. The method of claim 9, wherein the training signal is transmitted in the downlink portion and the training portion of the special subframe.

12. The method of claim 1, wherein transmitting the training signal comprises:

generating a plurality of training sequences from a set of sequences, the plurality of training sequences generated in accordance with a communications system requirement;

mapping a first training sequence to a transmit antenna;

multiplexing the mapped training sequence with data symbols thereby producing a transmission stream; and

transmitting the transmission stream as the training signal.

13. The method of claim 12, wherein each sequence in the set of sequences has a correlation matrix that is a scaled identity matrix.

14. The method of claim 12, wherein transmitting the transmission stream further comprises filtering the transmission stream.

15. The method of claim 12, further comprising appending a cyclic prefix to the mapped training sequence prior to multiplexing.

16. A device configured for full-duplex operation comprises:

a transmitter configured to transmit a training signal derived from a sequence, the training signal configured to facilitate an estimation of a channel impulse response (CIR) for a communications channel between a transmit antenna of the device and a receive antenna of the device;

a processor operatively coupled to the transmitter, the processor configured to estimate the CIR for the communications channel, to cancel self-interference present in received signals in accordance with the estimated CIR, the received signals corresponding to a first transmission at the receive antenna, the self-interference arising from a second transmission made by the transmit antenna of the device, thereby producing an interference canceled received signal, and to process the interference canceled received signal; and

a receiver operatively coupled to the processor, the receiver configured to receive the signals.

17. The device of claim 16, wherein the processor is configured to cancel the self-interference present in the received signals in accordance with data associated with the second transmission.

18. The device of claim 16, wherein the sequence comprises a zero-correlation-zone (ZCZ) sequence.

19. The device of claim 16, wherein the training signal is derived from the sequence in accordance with a communications system requirement.

20. The device of claim 16, wherein the transmitter is configured to transmit the training signal in a half-duplex mode.

21. The device of claim 16, wherein the transmitter is configured to transmit the training signal in a training portion of a special subframe.

22. The device of claim 21, wherein the transmitter is configured to transmit the training signal in a downlink portion of the special subframe.

23. The device of claim 16, wherein the device comprises an evolved NodeB.

24. A communications system comprising:

a plurality of user equipments; and

a full-duplex device operatively coupled to the plurality of user equipments, the full-duplex device including

a processor, and

a non-transitory computer readable storage medium storing programming for execution by the processor, the programming including instructions to

transmit a training signal derived from a sequence, the training signal configured to facilitate an estimation of a channel impulse response (CIR) for a communications channel between a transmit antenna of the device and a receive antenna of the device,

estimate the CIR for the communications channel,

receive signals corresponding to a first transmission at the receive antenna,

cancelling self-interference present in the received signals in accordance with the estimated CIR, the self-interference arising from a second transmission made by the transmit antenna of the device, thereby producing an interference canceled received signal, and

processing the interference canceled received signal.

25. The communications system of claim 24, wherein the programming includes instructions to cancel the self-interference present in the received signals in accordance with data associated with the second transmission.

26. The communications system of claim 24, wherein the programming includes instructions to transmit the training signal in a special subframe comprising a downlink portion, a training portion, and an uplink portion.

27. The communications system of claim 24, wherein the programming includes instructions to generate a plurality of training sequences from a set of sequences, the plurality of training sequences generated in accordance with a communications system requirement, map a first training sequence to a transmit antenna, multiplex the mapped training sequence with data symbols thereby producing a transmission stream, and transmit the transmission stream as the training signal.

28. The communications system of claim 24, wherein the programming includes instructions to append a cyclic prefix to the mapped training sequence prior to multiplexing the mapped training sequence.