Windowing methods for efficient channel aggregation and deaggregation

Patent metadata

Field	Value
Publication number	US-10117247-B2
Application number	US-201615057645-A
Country	US
Kind code	B2
Filing date	Mar 1, 2016
Priority date	Mar 13, 2015
Publication date	Oct 30, 2018
Grant date	Oct 30, 2018

Abstract

A method implemented in a fronthaul communication unit, comprising applying, via a processor of the fronthaul communication unit, a plurality of first frequency-domain windowing (FDW) functions on a plurality of first communication channel signals to produce a plurality of first windowed signals, aggregating, via the processor, the plurality of first windowed signals to produce a first aggregated signal, and transmitting, via a frontend of the fronthaul communication unit, the first aggregated signal to a corresponding fronthaul communication unit over a fronthaul communication link to facilitate fronthaul communication.

First claim

What is claimed is:

1. A method implemented in a fronthaul communication unit, comprising:
applying, via a processor, a frequency-shifting (FS) function to one of a plurality of first communication channel signals in a time domain, wherein the FS function comprises

FS
⁢

⁢
1
⁢

(
k
)

=

exp

-
j

×
2
×
π
×
k

2
⁢

⁢
K

,

 where FS 1 (k) represents the FS function, exp represents an exponential function, j represents a square root of minus one, π represents the value 3.14159, k represents a time sample index of the one of the plurality of first communication channel signals in a time frame of K samples, and K corresponds to a size of a first discrete Fourier transform (DFT);
performing, via a processor, a plurality of DFTs on the plurality of first communication channel signals;
applying, via a processor of the fronthaul communication unit, a plurality of first frequency-domain windowing (FDW) functions on the plurality of first communication channel signals to produce a plurality of first windowed signals, with the FDW functions comprising a sequence of FDW coefficients, and with a first half of the FDW coefficients being symmetrical to a second half of the FDW coefficients;
aggregating, via the processor, the plurality of first windowed signals to produce a first aggregated signal, wherein aggregating the plurality of first windowed signals comprises performing a frequency-division multiplexing (FDM) on the plurality of first windowed signals; and
transmitting, via a frontend of the fronthaul communication unit, the first aggregated signal to a corresponding fronthaul communication unit over a fronthaul communication link to facilitate fronthaul communication.

2. The method of claim 1 , further comprising selecting, via the processor, the plurality of first FDW functions according to spectral properties of the plurality of first communication channel signals.

3. The method of claim 1 , wherein aggregating the plurality of first windowed signals further comprises:
performing an inverse DFT (IDFT) after applying the plurality of first FDW functions to produce an aggregated time signal;
applying a time-domain windowing (TDW) function to the aggregated time signal to produce a time-domain windowed signal; and
generating the first aggregated signal according to the time-domain windowed signal.

4. The method of claim 1 , further comprising:
performing, via the processor, a plurality of discrete Fourier transforms (DFTs) on the plurality of first communication channel signals before applying the plurality of first FDW functions; and
performing, via the processor, a plurality of inverse DFTs (IDFTs) on the plurality of first windowed signals;
wherein aggregating the first plurality of windowed signals comprises performing a time-division multiplexing (TDM) on the plurality of first windowed signals after performing the plurality of IDFTs.

5. The method of claim 1 , further comprising:
receiving, via the frontend, a second aggregated signal from the fronthaul communication link, wherein the second aggregated signal comprises a plurality of second communication channel signals;
demultiplexing, via the processor, the second aggregated signal to produce a plurality of demultiplexed signals corresponding to the plurality of second communication channel signals; and
applying, via the processor, a second FDW function to a first of the plurality of demultiplexed signals to produce a second windowed signal.

6. The method of claim 5 , wherein demultiplexing the second aggregated signal comprises:
performing, via the processor, a discrete Fourier transform (DFT) on the second aggregated signal to produce an aggregated frequency signal; and
performing, via the processor, a frequency-division demultiplexing on the aggregated frequency signal to produce the plurality of demultiplexed signals.

7. The method of claim 6 , further comprising:
performing, via the processor, an inverse DFT (IDFT) on the second windowed signal to produce a time signal; and
applying, via the processor, a frequency-shifting (FS) function to the time signal to produce a frequency-shifted signal,
wherein the FS function comprises

FS
⁢

⁢
2
⁢

(
k
)

=

exp

j
×
π
×
π
×
k

K

,

 where FS 2 (k) represents the FS function, exp represents an exponential function, j represents the square root of minus one, π represents the value 3.14159, k represents a time sample index of the time signal in a time frame of K time samples, and K corresponds to a size of the IDFT.

8. The method of claim 7 , further comprising applying, via the processor, a time-domain windowing (TDW) function to the time signal before applying the FS function.

9. The method of claim 5 , wherein demultiplexing the second aggregated signal comprises performing, via the processor, a time-division demultiplexing on the second aggregated signal, and wherein the method further comprises:
performing, via the processor, a discrete Fourier transform (DFT) on the first demuliplexed signal before applying the second FDW function; and
performing, via the processor, an inverse DFT (IDFT) on the second windowed signal to produce a time signal.

10. A wireless fronthaul unit comprising:
a processor configured to:
apply a frequency-shifting (FS) function to one of a plurality of first communication channel signals in a time domain, wherein the FS function comprises

FS
⁢

⁢
2
⁢

(
k
)

=

exp

Assignees

• Futurewei Technologies Inc

Inventors

• Zeng Huaiyu
• Liu Xiang

Classifications

• H04L5/0035

  Resource allocation in a cooperative multipoint environment · CPC title

• H04L5/001

  the frequencies being arranged in component carriers · CPC title

• H04W72/0453 Primary

  Resources in frequency domain, e.g. a carrier in FDMA · CPC title

• H04L27/2636

  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 title

• H04L5/0023

  Time-frequency-space · CPC title