Processing method based on OFDM-TDMA two-way service and communications device

Patent metadata

Field	Value
Publication number	US-9838073-B2
Application number	US-201414570983-A
Country	US
Kind code	B2
Filing date	Dec 15, 2014
Priority date	Jun 20, 2012
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

The present invention provides a processing method based on an OFDM-TDMA two-way service and a communications device. The method includes assigning timeslots in a TDMA frame structure to multiple users in a TDMA manner, so that each user has a different timeslot, and each timeslot of the users is simultaneously used for uplink and downlink communication. The methods further includes simultaneously sending a local-end OFDM signal and receiving a remote-end OFDM signal in each timeslot of the users, and cancelling, in an OSD manner, interference caused by an echo OFDM signal, which is produced according to the local-end OFDM signal, to the remote-end OFDM signal, where a spectrum of the echo OFDM signal and a spectrum of the remote-end OFDM signal overlap.

First claim

What is claimed is:

1. A processing method based on an orthogonal frequency division multiplexing Time Division Multiple Access (OFDM-TDMA) two-way service, the processing method comprising:
assigning, by a communications device, timeslots in a TDMA frame structure to multiple users in a TDMA manner, so that each user has a different timeslot, and each timeslot of the users is simultaneously used for uplink and downlink communication between a respective user and the communications device:
simultaneously sending a local-end OFDM signal to a respective user and receiving a remote-end OFDM signal from the respective user in a timeslot of the respective user by the communications device, the local-end OFDM signal and the remote-end OFDM signal being multiplexed on a same frequency spectrum at the same time: and
cancelling, by the communications device in an overlapped spectrum duplex (OSD) manner, interference caused by an echo OFDM signal, which is produced according to the local-end OFDM signal, to the remote-end OFDM signal by combining received signals with an echo cancellation OFDM signal, the echo cancellation OFDM signal being generated for cancelling the echo OFDM signal from the received signals, wherein the echo cancellation OFDM signal is generated at least in part based on a phase difference between the echo OFDM signal and the remote-end OFDM signal,
wherein the combining is only adding or subtracting,
wherein the received signals comprise the echo OFDM signal and the remote-end OFDM signal, and
wherein a spectrum of the echo OFDM signal and a spectrum of the remote-end OFDM signal overlap.

2. The processing method according to claim 1 , wherein cancelling the interference caused by the echo OFDM signal comprises:
obtaining, according to the echo OFDM signal and the remote-end OFDM signal, a phase difference between the echo OFDM signal and the remote-end OFDM signal, and a channel transfer function of an echo path;
generating the echo cancellation OFDM signal according to the phase difference, the channel transfer function of the echo path, and the local-end OFDM signal; and
subtracting the echo cancellation OFDM signal from the received signals, to cancel the echo OFDM signal in the received signals.

3. The processing method according to claim 1 , wherein cancelling the interference caused by the echo OFDM signal comprises:
performing analog-to-digital conversion processing on the received signals;
obtaining the echo cancellation OFDM signal according to the local-end OFDM signal; and
adding the echo cancellation OFDM signal and the received signals, on which the analog-to-digital conversion processing is performed, to cancel the echo OFDM signal in the received signals.

4. The processing method according to claim 1 , wherein cancelling the interference caused by the echo OFDM signal comprises:
obtaining the echo cancellation OFDM signal according to the local-end OFDM signal, and performing digital-to-analog conversion processing on the echo cancellation OFDM signal; and
adding the echo cancellation OFDM signal, on which the digital-to-analog conversion processing is performed, and the received signals, to cancel the echo OFDM signal in the received signals.

5. A processing method based on an orthogonal frequency division multiplexing Time Division Multiple Access (OFDM-TDMA) two-way service, the processing method comprising:
simultaneously sending a local-end OFDM signal to a communications device and receiving a remote-end OFDM signal from the communications device in an obtained assigned timeslot, the local-end OFDM signal and the remote-end OFDM signal being multiplexed on a same frequency spectrum at the same time: and
cancelling, in an overlapped spectrum duplex OSD manner, interference caused by an echo OFDM signal, which is produced according to the local-end OFDM signal, to the remote-end OFDM signal by combining received signals with an echo cancellation OFDM signal, the echo cancellation OFDM signal being generated for cancelling the echo OFDM signal from the received signals, wherein the echo cancellation OFDM signal is generated at least in part based on a phase difference between the echo OFDM signal and the remote-end OFDM signal,
wherein the combining is only adding or subtracting,
wherein the received signals comprise the echo OFDM signal and the remote-end OFDM signal, and
wherein a spectrum of the echo OFDM signal and a spectrum of the remote-end OFDM signal overlap.

6. The processing method according to claim 5 , wherein cancelling the interference caused by the echo OFDM signal comprises:
obtaining, according to the echo OFDM signal and the remote-end OFDM signal, a phase difference between the echo OFDM signal and the remote-end OFDM signal and a channel transfer function of an echo path;
generating the echo cancellation OFDM signal according to the phase difference, the channel transfer function of the echo path, and the local-end OFDM signal; and
subtracting the echo cancellation OFDM signal from the received signals, to cancel the echo OFDM signal in the received signals.

7. The processing method according to claim 5 , wherein cancelling the interference caused by the echo OFDM signal comprises:
performing analog-to-digital conversion processing on the received signals;
obtaining the echo cancellation OFDM signal according to the local-end OFDM signal; and
adding the echo cancellation OFDM signal and the received signals, on which the analog-to-digital conversion processing is performed, to cancel the echo OFDM signal in the received signals.

8. The processing method according to claim 5 , wherein cancelling the interference caused by the echo OFDM signal comprises:
obtaining the echo cancellation OFDM signal according to the local-end OFDM signal, and performing digital-to-analog conversion processing on the echo cancellation OFDM signal; and
adding the echo cancellation OFDM signal, on which the digital-to-analog conversion processing is performed, and the received signals, to cancel the echo OFDM signal in the received signals.

9. A communications device, comprising:
a processor; and
a non-transitory computer-readable storage medium storing a program to be executed by the processor, the program including instructions for:
assigning timeslots in a Time Division Multiple Access (TDMA) frame structure to multiple users in a TDMA manner, so that each user has a different timeslot, and each timeslot of the users is simultaneously used for uplink and downlink communication between a respective user and the communications device:
simultaneously sending a local-end orthogonal frequency division multiplexing (OFDM) signal to a respective user and receive a remote-end OFDM signal from the respective user in a timeslot of the respective user, the local-end OFDM signal and the remote-end OFDM signal being multiplexed on a same frequency spectrum at the same time: and
cancelling, in an overlapped spectrum duplex (OSD) manner, interference caused by an echo OFDM signal, which is produced according to the local-end OFDM signal, to the remote-end OFDM signal by combining received signals with an echo cancellation OFDM signal, the echo cancellation OFDM signal being generated for cancelling the echo OFDM signal from the received signals, wherein the echo cancellation OFDM signal is generated at least in part based on a phase difference between the echo OFDM signal and the remote-end OFDM signal,
wherein the combining is only adding or subtracting,
wherein the received signals comprise the echo OFDM signal and the remote-end OFDM signal, and
wherein a spectrum of the echo OFDM signal and a spectrum of the remote-end OFDM signal overlap.

10. The communi

Assignees

• Huawei Tech Co Ltd

Inventors

• Shi Cao
• Pan Zhong

Classifications

• H04L5/0044

  Allocation of payload; Allocation of data channels, e.g. PDSCH or PUSCH · CPC title

• H04B3/20 Primary

  Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other · CPC title

• H04L5/0007

  the frequencies being orthogonal, e.g. OFDM(A) or DMT · CPC title

• H04L5/0037

  Inter-user or inter-terminal allocation · CPC title

• H04L5/1461

  Suppression of signals in the return path, i.e. bidirectional control circuits · CPC title