Peak-to-Average Power Ratio (PAPR) Reduction in Fronthauls

Patent metadata

Field	Value
Publication number	US-2016373283-A1
Application number	US-201615182362-A
Country	US
Kind code	A1
Filing date	Jun 14, 2016
Priority date	Jun 19, 2015
Publication date	Dec 22, 2016
Grant date	—

Abstract

An apparatus comprises: a receiver port configured to receive an input signal comprising in-phase and quadrature (IQ) data and control words (CWs); a peak-to-average power (PAPR) reducer coupled to the receiver port and configured to: receive the IQ data, process the IQ data, separate the IQ data into a clipped signal and a peak signal, and determine peak information associated with the peak signal; and a transmitter port coupled to the PAPR reducer and configured to separately transmit the clipped signal and the peak information. A method comprises: receiving an input signal comprising first data and second data; processing the first data; separating the first data into a clipped signal and a peak signal; determining peak information associated with the peak signal; and transmitting the clipped signal and the peak information.

First claim

What is claimed is:

1 . An apparatus comprising:
a receiver port configured to receive an input signal comprising in-phase and quadrature (IQ) data and control words (CWs); a peak-to-average power (PAPR) reducer coupled to the receiver port and configured to:
receive the IQ data,
process the IQ data,
separate the IQ data into a clipped signal and a peak signal, and
determine peak information associated with the peak signal; and
a transmitter port coupled to the PAPR reducer and configured to separately transmit the clipped signal and the peak information.

2 . The apparatus of claim 1 , wherein the transmitter port is further configured to not transmit the peak signal.

3 . The apparatus of claim 1 , wherein the transmitter port is further configured to:
transmit the clipped signal using an IQ channel; and transmit the peak information using a CW channel.

4 . The apparatus of claim 3 , wherein the IQ channel is not substantially error-free and the CW channel is substantially error-free.

5 . The apparatus of claim 1 , wherein the PAPR reducer is further configured to further process the input signal according to the following algorithm:
if s ( n )> V max , k ( n )=ceiling[( s ( n )− V max )/Δ]
p ( n )= k ( n )*Δ
c ( n )= s ( n )− p ( n );
else if s ( n )<− V max ,
k ( n )=floor[( s ( n )+ V max)/Δ]
p ( n )= k ( n )*Δ.
c ( n )= s ( n )− p ( n );
else, p ( n )=0 c ( n )= s ( n ),
wherein s(n) is the input signal, n is a time index or a frequency index, V max is a clipping threshold, k(n) is a quantization level, Δ is a quantization step, p(n) is the peak signal, and c(n) is the clipped signal, and wherein the transmitter port is further configured to transmit n and k(n) using a CW channel.

6 . The apparatus of claim 1 , wherein the PAPR reducer is further configured to further process the input signal according to the following algorithm:
if s ( n )> V max , p ( n )= S max −V max c ( n )= s ( n )− p ( n );
else if s ( n )<− V max ,
p ( n )= S max −V max
c ( n )= s ( n )+ p ( n ); else, p ( n )=0 c ( n )= s ( n ),
wherein s(n) is the input signal, n is a time index or a frequency index, V max is a clipping threshold, p(n) is the peak signal, S max is a maximum amplitude of the input signal, and c(n) is the clipped signal, and wherein the transmitter port is further configured to transmit n using a CW channel.

7 . The apparatus of claim 1 , wherein the PAPR reducer is further configured to further process the input signal according to the following algorithm:
if | s ( n )|> V max, α= V max /S max ,
c ( n )=α* s ( n );
else c ( n )= s ( n ),
wherein s(n) is the input signal, n is a time index or a frequency index, a is a constant, V max is a clipping threshold, S max is a maximum amplitude of the input signal, and c(n) is the clipped signal, and wherein the transmitter port is further configured to transmit n using a CW channel.

8 . The apparatus of claim 1 , wherein the PAPR reducer is further configured to further process the input signal according to the following algorithm:
if s ( n )> V max , c ( n )=2 *V max −s ( n ); else if s ( n )<− V max , c ( n )=−2 *V max −s ( n );
else c ( n )= s ( n ),
wherein s(n) is the input signal, n is a time index or a frequency index, V max is a clipping threshold, and c(n) is the clipped signal, and wherein the transmitter port is further configured to transmit n using a CW channel.

9 . The apparatus of claim 1 , wherein the PAPR reducer is further configured to separate the IQ data into the clipped signal and the peak signal based on a clipping threshold that is 0.5 times to 0.8 times a maximum amplitude of the IQ data.

10 . A method comprising:
receiving an input signal comprising first data and second data; processing the first data; separating the first data into a clipped signal and a peak signal; determining peak information associated with the peak signal; and transmitting the clipped signal and the peak information.

11 . The method of claim 10 , wherein the first data are in-phase and quadrature (IQ) data and the second data are control words (CWs).

12 . The method of claim 10 , further comprising further transmitting the clipped signal using an IQ channel and the peak information using a CW channel.

13 . The method of claim 12 , wherein the IQ channel is not substantially error-free and the CW channel is substantially error-free.

14 . The method of claim 10 , wherein the peak information comprises an index for each non-zero value of the peak signal, wherein the index represents time.

15 . The method of claim 14 , wherein the peak information further comprises a quantization level for each non-zero value of the peak signal.

16 . The method of claim 10 , further comprising separating the first data into the clipped signal and the peak signal based on a clipping threshold that is 0.5 times to 0.8 times a maximum amplitude of the first data.

17 . An apparatus comprising:
a receiver port configured to:
receive a clipped signal using a first channel that is not substantially error-free, and
receive peak information using a second channel that is substantially error-free,
wherein the peak information is associated with a peak signal; and a peak recoverer coupled to the receiver port and configured to recover the peak signal based on the clipped signal and the peak information.

18 . The apparatus of claim 17 , wherein the peak recoverer is further configured to combine the clipped signal and the peak signal to form an input signal.

19 . The apparatus of claim 17 , wherein the peak information consists of an index for each non-zero value of the peak signal.

20 . The apparatus of claim 17 , wherein the peak information consists of an index and a quantization level for each non-zero value of the peak signal.

Assignees

• Futurewei Technologies Inc

Inventors

• Zeng Huaiyu
• Liu Xiang
• Effenberger Frank
• Long Guozhu

Classifications

• H04L27/2623 Primary

  Reduction thereof by clipping · CPC title

• H04W52/36

  with a discrete range or set of values, e.g. step size, ramping or offsets · CPC title

• H04L27/3411

  reducing the peak to average power ratio or the mean power of the constellation; Arrangements for increasing the shape gain of a signal set · CPC title

• H04L27/366

  Arrangements for compensating undesirable properties of the transmission path between the modulator and the demodulator · CPC title