US 10,701,685 B2Granted

Method and apparatus for asynchronous OFDMA/SC-FDMA

AssigneeHuawei Technologies Co., Ltd.

InventorsJavad Abdoli, Ming Jia, Jianglei Ma

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Abstract

Cyclic prefix based OFDM (CP-OFDM) signals can be filtered using a digital filter whose filter length exceeds the length of a cyclic prefix in CP-OFDM symbols of the signal. In one example, the duration of the filtered CP-OFDM symbol may be expressed by the following equation: M=N+L−1, where M is the duration of the filtered CP-OFDM signal, N is a duration of the CP-OFDM signal, and L is the filter length of the digital filter. Digitally filtering the CP-OFDM signal may include convolving a filtering signal with the CP-OFDM signal. The digital filter may include a finite impulse response (FIR) filter or an infinite impulse response (IIR) filter. In some embodiments, a different digital filter may be applied to each sub-band of the CP-OFDM signal.

Claims23

Dependent claims

A method for communicating orthogonal frequency-division multiplexing (OFDM) signals in a wireless communication system, the method comprising:

obtaining, by a first user equipment (UE), a cyclic prefix based orthogonal frequency-division multiplexed (CP-OFDM) signal comprising a plurality of CP-OFDM symbols having a cyclic prefix comprising a repetition of an end of a corresponding CP-OFDM symbol;
applying a digital filter to the CP-OFDM signal to obtain a filtered CP-OFDM signal, wherein main lobes of the filtered CP-OFDM signal have bandwidths in the frequency domain that are equal to bandwidths associated with a plurality of resource blocks (RBs);
and
transmitting, to a base station, the filtered CP-OFDM signal over the plurality of RBs, wherein the filtered CP-OFDM signal is decoded by the base station based on a first per-UE based time synchronization corresponding to the first UE, wherein a second filtered CP-OFDM signal from a second UE is decoded by the base station based on a second per-UE based time synchronization corresponding to the second UE, the second per-UE based time synchronization being different from the first per-UE based time synchronization, and wherein the filtered CP-OFDM signal and the second filtered CP-OFDM signal are received as a combined signal by the base station.

1 more element

A first UE, comprising:

a processor;
and
a computer readable storage medium storing programming comprising instructions for execution by the processor, that when executed cause the first UE to:
obtain a cyclic prefix based orthogonal frequency-division multiplexed (CP-OFDM) signal comprising a plurality of CP-OFDM symbols having a cyclic prefix comprising a repetition of an end of a corresponding CP-OFDM symbol;
apply a digital filter to the CP-OFDM signal to obtain a filtered CP-OFDM signal, wherein main lobes of the filtered CP-OFDM signal have bandwidths in the frequency domain that are equal to bandwidths associated with a plurality of resource blocks (RBs);
and
transmit, to a base station, the filtered CP-OFDM signal over the plurality of RBs, wherein the filtered CP-OFDM signal is decoded by the base station based on a first per-UE based time synchronization corresponding to the first UE, wherein a second filtered CP-OFDM signal from a second UE is decoded by the base station based on a second per-UE based time synchronization corresponding to the second UE, the second per-UE based time synchronization being different from the first per-UE based time synchronization, and wherein the filtered CP-OFDM signal and the second filtered CP-OFDM signal are received as a combined signal by the base station.

4 more elements

A method for receiving orthogonal frequency-division multiplexing (OFDM) signals in a wireless communication system, the method comprising:

receiving, by a base station from a first user equipment (UE), a cyclic prefix based orthogonal frequency-division multiplexed (CP-OFDM) signal over a plurality of resource blocks (RBs), the CP-OFDM signal comprising a plurality of CP-OFDM symbols having a cyclic prefix comprising a repetition of an end of a corresponding CP-OFDM symbol;
receiving, by the base station from a second UE, a second CP-OFDM signal, wherein the CP-OFDM signal and the second CP-OFDM signal are received as a combined signal;
applying a digital filter to the CP-OFDM signal to obtain a filtered CP-OFDM signal, wherein main lobes of the filtered CP-OFDM signal have bandwidths in the frequency domain that are equal to bandwidths associated with the plurality of RBs;
applying a second digital filter to the second CP-OFDM signal to obtain a second filtered CP-OFDM signal;
performing a first per-UE based time synchronization of the filtered CP-OFDM signal, the first per-UE based time synchronization corresponding to the first UE;
performing a second per-UE based time synchronization of the second filtered CP-OFDM signal, the second per-UE based time synchronization corresponding to the second UE, the second per-UE based time synchronization being different from the first per-UE based time synchronization;
and
processing the filtered CP-OFDM signal and the second filtered CP-OFDM signal.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/836,538Filed 26 Aug 2015 · continuation in part
Priority: 31 Mar 2014
Published: US 2016/0192353 A130 Jun 2016
Granted: 30 Jun 2020
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

H04L 27/26265
Arrangements specific to the transmitter only: arrangements for sidelobes suppression specially adapted to multicarrier systems, e.g. spectral…
H04L 5/0007
Time-frequency: the frequencies being orthogonal, e.g. OFDM or DMT
H04L 5/0066
Allocation criteria: requirements on out-of-channel emissions
H04L 27/2636
Inverse fast Fourier transform [IFFT] or inverse discrete Fourier transform [IDFT] modulators in combination with other circuits for modulation:…

Family

Application14/231,217Parent of this continuation-in-part · filed 31 Mar 2014
US 2016/0192353 A1Pre-grant publication · published 30 Jun 2016
US 9,419,770 B2Parent of this continuation-in-part
US 2015/0280886 A1Published application
US 10,701,685 B2This patent

From the US filing history. Foreign family members aren’t listed.