Method and apparatus for data-aided iterative channel estimation

Patent metadata

Field	Value
Publication number	US-10182439-B2
Application number	US-201615131781-A
Country	US
Kind code	B2
Filing date	Apr 18, 2016
Priority date	Feb 16, 2016
Publication date	Jan 15, 2019
Grant date	Jan 15, 2019

Abstract

An apparatus and a method. The apparatus includes a channel estimation (CE) module, including a first input for receiving pilot resource element (RE) observations, a second input for receiving data RE observations, a third input for receiving log-likelihood ratios (LLRs), and an output; a detector, including a first input connected to the output of the CE module, a second input for receiving data RE observations, and an output connected to the third input of the CE module; and a decoder, including an input connected to the third input of the CE module, and an output.

First claim

What is claimed is:

1. A method, comprising:
(a) determining a channel estimate using a pilot signal, wherein a counter n is initialized to n=0, where n is an integer;
(b) determining a log likelihood ratio (LLR) of data symbols by a detector based on the channel estimate for one or more layers L, wherein L is an integer indicating a total number of layers;
(c) performing decoding of the LLR of the data symbols if n is equal to a predetermined number of iterations N, otherwise proceeding to step (d), where N is an integer;
(d) determining the channel estimate using the LLR of the data symbols from step (c) and data resource element (RE) observations;
(e) determining the LLR of the data symbols by the detector based on the channel estimate from step (d);
(f) incrementing n by 1 and returning to step (c);
(g) estimating channels for the L layers using pilot signals, wherein the counter n is initialized to n=0, and wherein L is greater than or equal to 1;
(h) performing detection for the L layers;
(i) performing decoding if n is equal to the predetermined number of iterations N, otherwise setting l equal to 1, wherein l is an integer indicating a current layer;
(j) performing data-aided channel estimation (CE) for the L layers;
(k) performing detection of the current layer l;
(l) incrementing l by 1; and
(m) if l is greater than or equal to L then incrementing n by 1 and returning to step (i), otherwise, returning to step (j).

2. The method of claim 1 , wherein estimating the channels for the L layers using the pilot signals is comprised of performing pilot-aided frequency domain (FD) minimum mean square error (MMSE) CE for orthogonal frequency-division multiplexing (OFDM) with the pilot signals and time division (TD) interpolation,
wherein if n is equal to the predetermined number of iterations N then performing decoding and terminating the method, otherwise setting l equal to 1 is comprised of if a cyclic redundancy check (CRC) passes or if n is equal to the predetermined number of iterations N then performing decoding and terminating the method, otherwise setting l equal to 1, and
wherein performing the data-aided CE for the L layers is comprised of performing data-aided FD CE for OFDM symbols with the pilot signals and the TD interpolation.

3. A method, comprising:
(a) determining a channel estimate using a pilot signal, wherein a counter n is initialized to n=0, where n is an integer;
(b) determining a log likelihood ratio (LLR) of data symbols by a detector based on the channel estimate for one or more layers L, wherein L is an integer indicating a total number of layers;
(c) performing decoding of the LLR of the data symbols if n is equal to a predetermined number of iterations N, otherwise proceeding to step (d), where N is an integer;
(d) determining the channel estimate using the LLR of the data symbols from step (c) and data resource element (RE) observations;
(e) determining the LLR of the data symbols by the detector based on the channel estimate from step (d);
(f) incrementing n by 1 and returning to step (c);
(g) sorting resource elements (REs) in descending order by channel correlation to a target RE;
(h) setting a counter i equal to i=0 and a count D to an empty set Φ, wherein i is an integer and represents a number of RE, D represents a set of selected data REs, Φ indicates that D is initialized to the empty set Φ, and the counter n equals to n=0;
(i) incrementing i by 1;
(j) setting RE(i) to an ith RE after sorting;
(k) setting an ith log-likelihood ratio (LLR(i)) to an LLR feedback for the RE(i);
(l) setting an ith variance (VAR(i)) to a variance of a symbol in the RE(i) computed using the LLR(i);
(m) determining if the VAR(i) is less than a pre-determined threshold;
(n) if the VAR(i) is greater than or equal to the pre-determined threshold then proceeding to step (p);
(o) if the VAR(i) is less than the pre-determined threshold then setting D to the union of D and i, incrementing n by 1, and proceeding to step (p); and
(p) if i is equal to the number of REs or n is equal to N then terminating the method, otherwise, returning to step (i).

4. A method, comprising:
(a) determining a channel estimate using a pilot signal, wherein a counter n is initialized to n=0, where n is an integer;
(b) determining a log likelihood ratio (LLR) of data symbols by a detector based on the channel estimate for one or more layers L, wherein L is an integer indicating a total number of layers;
(c) performing decoding of the LLR of the data symbols if n is equal to a predetermined number of iterations N, otherwise proceeding to step (d), where N is an integer;
(d) determining the channel estimate using the LLR of the data symbols from step (c) and data resource element (RE) observations;
(e) determining the LLR of the data symbols by the detector based on the channel estimate from step (d);
(f) incrementing n by 1 and returning to step (c);
(g) performing pilot-aided frequency division (FD) minimum mean square error (MMSE) channel estimation (CE) for orthogonal frequency division multiplexing (OFDM) symbols with pilot signals, wherein the counter n is initialized to n=0;
(h) performing time division (TD) interpolation on the result of step (g);
(i) performing detection on the result of step (h);
(j) if n is equal to the predetermined number of iterations N then performing decoding and terminating the method, otherwise proceeding to step (k);
(k) performing data-aided FD CE for OFDM symbols with the pilot signals;
(l) performing TD interpolation on the data-aided FD CE for OFDM symbols with the pilot signals of step (k);
(m) performing detection on the result of step (l); and
(n) incrementing n by 1 and returning to step (j).

5. A method, comprising:
(a) determining a channel estimate using a pilot signal, where a counter n is initialized to n=0, wherein n is an integer;
(b) determining a first log likelihood ratio (LLR) of data symbols by a detector based on the channel estimate for one or more layers L, where L is an integer indicating a total number of layers;
(c) determining a second LLR of the data symbols by a decoder based on the first LLR;
(d) determining the channel estimate using the second LLR of the data symbols from step (c) and data resource (RE) observations;
(e) determining the first LLR by the detector based on the channel estimate from step (d);
(f) determining the second LLR by the decoder based on the first LLR from step (e);
(g) incrementing n by 1;
(h) returning to step (d) based on one of not passing a cyclic redundancy check (CRC) and n is less than a predetermined number of iterations N;
(i) estimating channels for the L layers using pilot signals, wherein the counter n is initialized to n=0, and wherein L is greater than or equal to 1;
(j) performing detection and decoding for the L layers;
(k) terminating if the CRC passes for the L layers or n is equal to the predetermined number of iterations N, otherwise setting l equal to 1, wherein 1 is an integer indicating a current layer;
(l) performing data-aided channel estimation (CE) for the L layers;
(m) performing detection and decoding of the current layer l;
(n) incrementing l by 1; and
(o) if l is greater than or equal to L then incrementing n by 1 and returning to step (k), otherwise, returning to step (l).

6. The method of claim 5 , wherein estimating channels for the L layers using pilot signals is comprised of performing pilot-aided frequency domain (FD) minimum mean square error (MMSE) CE for orthogonal frequency-division multiplexing (OFDM) with the pilot signals and time division (TD) interpolation, and
wherein performing the data-aided CE for the L layers is comprised of performing data-aided FD CE for OFDM symbols with the pilot sign

Assignees

• Choi Yoo Jin
• Bai Dongwoon
• Kim Sungsoo
• Lee Jungwon
• Samsung Electronics Co Ltd

Inventors

• Choi Yoo Jin
• Bai Dongwoon
• Kim Sungsoo
• Lee Jungwon

Classifications

• H04L1/1819

  with retransmission of additional or different redundancy · CPC title

• H04L5/0073

  Allocation arrangements that take into account other cell interferences · CPC title

• H04L27/2017

  in which the phase changes are non-linear, e.g. generalized and Gaussian minimum shift keying, tamed frequency modulation (H04L27/201 takes precedence) · CPC title

• H04B1/10

  Means associated with receiver for limiting or suppressing noise or interference · CPC title

• H04W72/0453 Primary

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