U.S. patent application number 15/262796 was filed with the patent office on 2017-01-05 for method and apparatus for tracking beam in wireless communication system.
The applicant listed for this patent is Samsung Electronics Co., Ltd.. Invention is credited to Tae-Young KIM, Jeong-Ho PARK, Hyun-Kyu YU.
Application Number | 20170005711 15/262796 |
Document ID | / |
Family ID | 47669096 |
Filed Date | 2017-01-05 |
United States Patent
Application |
20170005711 |
Kind Code |
A1 |
YU; Hyun-Kyu ; et
al. |
January 5, 2017 |
METHOD AND APPARATUS FOR TRACKING BEAM IN WIRELESS COMMUNICATION
SYSTEM
Abstract
A method and an apparatus for tracking a beam in a wireless
communication system are provided. In the method, a plurality of
downlink reference signals are received from a base station and at
least one downlink transmission beam pattern is determined. A
plurality of uplink reference signals are transmitted to the base
station, each includes identifier information corresponding to the
determined at least one downlink transmission beam pattern.
ACKnowledgement (ACK) information indicating that the base station
has successfully received an identifier included in the identifier
information corresponding to the determined at least one downlink
transmission beam pattern from identifier information corresponding
to an uplink transmission beam pattern and that the plurality of
uplink reference signals from the base station is received.
Inventors: |
YU; Hyun-Kyu; (Yongin-si,
KR) ; KIM; Tae-Young; (Seongnam-si, KR) ;
PARK; Jeong-Ho; (Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Electronics Co., Ltd. |
Suwon-si |
|
KR |
|
|
Family ID: |
47669096 |
Appl. No.: |
15/262796 |
Filed: |
September 12, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13569550 |
Aug 8, 2012 |
9450661 |
|
|
15262796 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04B 7/0684 20130101;
H04B 7/0623 20130101; H04B 7/0617 20130101; H04L 5/0048 20130101;
H04L 1/189 20130101; H04W 72/042 20130101; H04W 88/02 20130101 |
International
Class: |
H04B 7/06 20060101
H04B007/06 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 11, 2011 |
KR |
10-2011-0080062 |
Claims
1. A method for operating a receiver in a wireless communication
system, the method comprising: receiving, from a transmitter, a
plurality of reference signals through a plurality of reception
beams; determine at least one transmission/reception beam pair
based on the plurality of reference signals; transmitting, to the
transmitter, first information indicating at least one transmission
beam of the at least one transmission/reception beam pair; and
receiving, from the transmitter, acknowledgement (ACK) information
indicating that the first information is received by the
transmitter.
2. The method of claim 1, wherein the transmitting; to the
transmitter, of the first information indicating the at least one
transmission beam of the at least one transmission/reception beam
pair comprises transmitting, to the transmitter, a plurality of
other reference signals comprising the first information indicating
the at least one transmission beam of the at least one
transmission/reception beam pair through a plurality of
transmission beams, and wherein the receiving, from the
transmitter, of the ACK information indicating that the first
information is received by the transmitter comprises receiving,
from the transmitter, the ACK information indicating that the first
information is received by the transmitter and second information
indicating at least one other transmission beam determined based on
the plurality of other reference signals by the transmitter.
3. The method of claim 2, further comprising: transmitting, if the
second information is received from the transmitter, other ACK
information to the transmitter; and transmitting, if the second
information is not received from the transmitter, negative
acknowledgement (NACK) information to the transmitter.
4. The method of claim 2, further comprising: re-transmitting, if
the second information is received and negative acknowledgement
(NACK) information indicating that the first information is not
received by the transmitter is received from the transmitter, the
first information to the transmitter.
5. The method of claim 2, further comprising: re-transmitting, if
the second information is not received and negative acknowledgement
(NACK) information indicating that the first information is not
received by the transmitter is received from the transmitter, the
plurality of other reference signals comprising the first
information to the transmitter; and re-receiving, from the
transmitter, the second information and the ACK information.
6. A method for operating a transmitter, the method comprising:
transmitting, to a receiver, a plurality of reference signals
through a plurality of transmission beams; receiving, from the
receiver, first information indicating at least one transmission
beam determined based on the plurality of reference signals by the
receiver; and transmitting, to the receiver, acknowledgement (ACK)
information indicating that th e first information is received.
7. The method of claim 6, wherein the receiving, from the receiver,
of the first information indicating the at least one transmission
beam determined based on the plurality of reference signals by the
receiver comprises receiving, from the receiver, a plurality of
other reference signals comprising the first information indicating
the at least one transmission beam determined based on the
plurality of reference signals by the receiver through a plurality
of reception beams, and further comprising determining at least one
transmission/reception beam pair based on the plurality of other
reference signals, wherein the transmitting, to the receiver, of
the ACK information indicating that the first information is
received comprises transmitting, to the receiver, the ACK
information indicating that the first information is received and
second information indicating at least one other transmission beam
of the at least one transmission/reception beam pair.
8. The method of claim 7, further comprising: receiving, if the
second information is received by the receiver; other ACK
information from the receiver; and receiving, if the second
information is not received by the receiver, negative
acknowledgement (NACK) information from the receiver.
9. The method of claim 7, further comprising: re-receiving, if the
second information is transmitted and negative acknowledgement
(NACK) information indicating that the first information is not
received is transmitted to the receiver, the first information from
the receiver.
10. The method of claim 7, further comprising: re-receiving, if the
second information is not transmitted and negative acknowledgement
(NACK) information indicating that the first information is not
received is transmitted to the receiver, the plurality of other
reference signals comprising the first information from the
receiver; and re-transmitting; to the receiver; the second
information and the ACK information.
11. A receiver in wireless communication system, the receiver
comprising: a reception unit configured to receive, from a
transmitter, a plurality of reference signals through a plurality
of reception beams; a control unit configured to determine at least
one transmission/reception beam pair based on the plurality of
reference signals; and a transmission unit configured to transmit,
to the transmitter, first information indicating at least one
transmission beam of the at least one transmission/reception beam
pair, wherein the reception unit is further configured to receive;
from the transmitter, acknowledgement (ACK) information indicating
that the first information is received by the transmitter.
12. The receiver of claim 11, wherein the transmission unit is
configured to transmit, to the transmitter, a plurality of other
reference signals comprising the first information indicating the
at least one transmission beam of the at least one
transmission/reception beam pair through a plurality of
transmission beams, and wherein the reception unit is configured to
receive, from the transmitter, the ACK information indicating that
the first information is received by the transmitter and second
information indicating at least one other transmission beam
determined based on the plurality of other reference signals by the
transmitter.
13. The receiver of claim 12, wherein the transmission unit is
further configured to: transmit, if the second information is
received from the transmitter, other ACK information to the
transmitter; and transmit, if the second information is not
received from the transmitter, negative acknowledgement (NACK)
information to the transmitter.
14. The receiver of claim 12, wherein the transmission unit is
further configured to re-transmit, if the second information is
received and negative acknowledgement (NACK) information indicating
that the first information is not received by the transmitter is
received from the external device, the first information to the
transmitter.
15. The receiver of claim 12, wherein the transmission unit is
further configured to re-transmit, if the second information is not
received and negative acknowledgement (NACK) information indicating
that the first information is not received by the transmitter is
received from the external device, the plurality of other reference
signals comprising the first information to the transmitter, and
wherein the reception unit is further configured to re-receive,
from the transmitter, the second information and the ACK
information.
16. A transmitter in wireless communication system, the transmitter
comprising: a transmission unit configured to transmit, to a
receiver, a plurality of reference signals through a plurality of
transmission beams; and a reception unit configured to receive,
from the receiver, first information indicating at least one
transmission beam determined based on the plurality of reference
signals by the receiver, wherein the transmission unit is further
configured to transmit, to the receiver, acknowledgement (ACK)
information indicating that the first information is received.
17. The transmitter of claim 16, further comprising processor
controller unit, wherein the reception unit is configured to
receive, from the receiver, a plurality of other reference signals
comprising the first information indicating that the at least one
transmission beam determined based on the plurality of reference
signals by the receiver through a plurality of reception beams,
wherein the controller unit is configured to determine at least one
transmission/reception beam pair based on the plurality of other
reference signals, and wherein the transmission unit is configured
to transmit, to the receiver, second information indicating at
least one other transmission beam of the at least one
transmission/reception beam pair and the ACK information indicating
that the first information is received.
18. The transmitter of claim 17, wherein the reception unit is
further configured to: receive, if the second information is
received by the receiver, other ACK information from the receiver;
and receive, if the second information is not received by the
receiver, negative acknowledgement (NACK) information from the
receiver.
19. The transmitter of claim 17, wherein the reception unit is
further configured to re-receive, if the second information is
transmitted and negative acknowledgement (NACK) information
indicating that the first information is not received is
transmitted to the receiver, the first information from the
receiver.
20. The transmitter of claim 17, wherein the reception unit is
further configured to re-receive, if the second information is not
transmitted and negative acknowledgement (NACK) information
indicating that the first information is not received is
transmitted to the receiver, the plurality of other reference
signals comprising the first information from the receiver, and
wherein the transmission unit is further configured to re-transmit,
to the receiver, the second information and the ACK information.
Description
PRIORITY
[0001] This application is a continuation application of prior
application Ser. No. 13/569,550, filed on Aug. 8, 2012, which will
issue as U.S. Pat. No. 9,450,661 on Sep. 20, 2016 and claimed the
benefit under 35 U.S.C .sctn.119(a) of a Korean patent application
filed on Aug. 11, 2011 in the Korean Intellectual Property Office
and assigned Serial number 10-2011-0080062, the entire disclosure
of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a wireless communication
system. More particularly, the present invention relates to a
method and an apparatus for tracking a beam in a wireless
communication system.
[0004] 2. Description of the Related Art
[0005] Wireless communication systems have developed in a direction
for supporting a higher data transmission rate in order to meet
continuously increasing wireless data traffic demand. Recently,
4-Generation (4G) wireless systems have been pursued as a
technology for improving a spectral efficiency generally in order
to increase a data transmission rate. However, it is difficult to
meet an explosively increasing wireless data traffic demand using
only such a spectral efficiency improvement technology.
[0006] In order to address the increasing demand, a very wide
frequency band may be used. Yet, since it is very difficult to
secure a wide frequency band in a frequency band that is less than
10 GHz and is currently in use, a higher frequency band needs to be
secured. However, as a transmission frequency for wireless
communication is increased, the distance of reach, i.e., the range,
of a radio wave gets relatively short, and there is a reduction of
coverage area. In order to increase the distance of reach of the
radio wave, a beam-forming technology may be used.
[0007] Generally, transmission beam-forming is a method for
concentrating a region of propagation or transmission of a radio
wave in a specific direction using a plurality of antennas. A
plurality of antennas which are arranged together is referred to as
an antenna array, and an antenna included in the antenna array is
referred to as an array element. When transmission beam-forming is
used, a transmission distance of a signal may be increased, and
since the signal is generally not transmitted in other directions
except for a relevant direction, interference from other user
signals may be reduced significantly.
[0008] Meanwhile, a reception side, or a receiver, may perform
reception beam-forming using a reception antenna array. Reception
beam-forming also concentrates reception of a radio wave in a
specific direction to increase a gain of a signal entering the
receiver from a relevant direction and may exclude a signal
entering from other directions except for the relevant direction,
thereby excluding interfering signals. To perform basic
beam-forming, a technology for allowing a base station and a
terminal to efficiently select a transmission and/or reception beam
is required. In addition, if a beam is not correctly set due to a
specific error during a transmission and/or reception beam setting
process, then spectral efficiency deterioration may occur.
Accordingly, a base station should be allowed to control an error
state and a stable beam tracking method should be provided.
[0009] Therefore, a beam tracking method and an apparatus thereof,
for efficiently selecting a transmission and/or reception
beam-forming in a wireless communication system are required.
[0010] The above information is presented as background information
only to assist with an understanding of the present disclosure. No
determination has been made, and no assertion is made, as to
whether any of the above might be applicable as prior art with
regard to the present invention.
SUMMARY OF THE INVENTION
[0011] Aspects of the present invention are to address at least the
above-mentioned problems and/or disadvantages and to provide at
least the advantages described below. Accordingly, an aspect of the
present invention is to provide a method and an apparatus for
efficiently tracking a beam in a wireless communication system.
[0012] In accordance with an aspect of the present invention, a
method for tracking a beam by a terminal in a wireless
communication system is provided. The method includes receiving a
plurality of downlink reference signals from a base station to
determine at least one downlink transmission beam pattern,
transmitting, to the base station, a plurality of uplink reference
signals, each having identifier information corresponding to the
determined at least one downlink transmission beam pattern to the
base station, and receiving, from the base station, ACKnowledgement
(ACK) information indicating that an identifier included in the
identifier information corresponding to the determined at least one
downlink transmission beam pattern has been successfully received
in the base station from among identifier information corresponding
to an uplink transmission beam pattern and the plurality of uplink
reference signals.
[0013] In the embodiment, a wide beam pattern or a previously
received at least one downlink transmission beam pattern is used as
the downlink transmission beam pattern upon receiving at least one
of the first NACK information and the second NACK information
indicating that the base station has not successfully detected the
identifier included in the identifier information corresponding to
the determined at least one downlink transmission beam pattern.
[0014] In accordance with another aspect of the present invention,
a method for tracking a beam by a base station in a wireless
communication system is provided. The method includes transmitting
a plurality of downlink reference signals to a terminal, receiving,
from the terminal, a plurality of uplink reference signals, each
having identifier information corresponding to at least one
downlink transmission beam pattern determined by the terminal from
the terminal according to the plurality of downlink reference
signals, and transmitting ACK information indicating that
identifier information corresponding to an uplink transmission beam
pattern determined according to the plurality of uplink reference
signals and an identifier included in the identifier information
corresponding to the determined at least one downlink transmission
beam pattern have been successfully received.
[0015] In the embodiment, a wide beam pattern or a previously
received at least one downlink transmission beam pattern is used as
the downlink transmission beam pattern upon receiving at least one
of the first NACK information and the second NACK information
indicating that the base station has not successfully detected the
identifier included in the identifier information corresponding to
the determined at least one downlink transmission beam pattern.
[0016] In accordance with another aspect of the present invention,
a method for tracking a beam by a terminal in a wireless
communication system is provided. The method includes receiving,
from a base station, a plurality of downlink reference signals to
determine at least one downlink transmission beam pattern,
transmitting, to the base station, identifier information
corresponding to at least one downlink transmission pattern using
the determined at least one uplink transmission beam pattern, and
receiving ACK information from the base station upon the base
station successfully receiving the identifier information
corresponding to the at least one downlink transmission beam
pattern.
[0017] In accordance with another aspect of the present invention,
a method for tracking a beam by a base station in a wireless
communication system is provided. The method includes transmitting
a plurality of downlink reference signals to a terminal, receiving,
from the terminal, identifier information corresponding to at least
one downlink transmission beam pattern determined by the terminal
according to the plurality of downlink reference signals, and
transmitting ACK information to the terminal when an identifier
corresponding to the at least one downlink transmission beam
pattern is successfully received.
[0018] In accordance with another aspect of the present invention,
a method for tracking a beam by a terminal in a wireless
communication system is provided. The method includes transmitting
a plurality of uplink reference signals to a base station,
receiving, from the base station, identifier information
corresponding to an uplink transmission beam pattern according to
the plurality of uplink reference signals, and transmitting ACK or
Negative ACKnowledgement (NACK) according to whether the identifier
information corresponding to the uplink transmission beam pattern
is received.
[0019] In the embodiment, the method further comprises
retransmitting a plurality of uplink reference signals to the base
station upon the base station not successfully detecting index
information corresponding to an uplink transmission beam pattern
and re-receiving the identifier information corresponding to the
uplink transmission beam pattern from the base station according to
the plurality of uplink reference signals.
[0020] In accordance with another aspect of the present invention,
a method for tracking a beam by a base station in a wireless
communication system is provided. The method includes receiving a
plurality of uplink reference signals from a terminal,
transmitting, to the terminal, identifier information corresponding
to an uplink transmission beam pattern according to the plurality
of uplink reference signals, and receiving ACK or NACK according to
whether the identifier information corresponding to the uplink
transmission beam pattern is received.
[0021] In accordance with another aspect of the present invention,
an apparatus for tracking a beam by a terminal in a wireless
communication system is provided. The apparatus includes a
controller for receiving, from a base station, a plurality of
downlink reference signals from a base station to determine at
least one downlink transmission beam pattern, a transmitter for
transmitting, to the base station, a plurality of uplink reference
signals, each having identifier information corresponding to the
determined at least one downlink transmission beam pattern, and a
receiver for receiving, from the base station, ACK information
indicating that an identifier included in the identifier
information corresponding to the determined at least one downlink
transmission beam pattern has been successfully received at the
base station from among identifier information corresponding to an
uplink transmission beam pattern and the plurality of uplink
reference signals.
[0022] In the embodiment, the transmitter further transmits ACK
information to the base station upon successfully detecting the
identifier information corresponding to the uplink transmission
beam pattern, and transmits Negative ACKnowledgement (NACK)
information to the base station upon not successfully detecting the
identifier information corresponding to the uplink transmission
beam pattern.
[0023] In the embodiment, the controller further successfully
detects the identifier information corresponding to the uplink
transmission beam pattern, and the receiver re-receives, from the
base station, the identifier included in the identifier information
corresponding to the determined at least one downlink transmission
beam pattern according to a plurality of previous uplink
transmission beam patterns upon receiving Negative ACKnowledgement
(NACK) information indicating that the base station has not
successfully received the identifier included in the identifier
information corresponding to the determined at least one downlink
transmission beam pattern from among the plurality of uplink
reference signals.
[0024] In the embodiment, the transmitter further retransmits, to
the base station, a plurality of uplink reference signals
comprising identifier information corresponding to the determined
at least one downlink transmission beam pattern upon not
successfully detecting the identifier information corresponding to
the uplink transmission beam pattern and upon receiving Negative
ACKnowledgement (NACK) information indicating that the base station
has not successfully received the identifier included in the
identifier information corresponding to the at least one downlink
transmission beam pattern from among the plurality of uplink
reference signals, and the receiver re-receives ACK information
indicating that the base station has successfully received the
identifier included in the identifier information corresponding to
the determined at least one downlink transmission beam pattern from
among the identifier information corresponding to the uplink
transmission beam pattern and the plurality of uplink reference
signals.
[0025] In the embodiment, the controller further uses a wide beam
pattern or a previously received at least one downlink transmission
beam pattern as the downlink transmission beam pattern upon
receiving the NACK information indicating that the base station has
not successfully received the identifier corresponding to the at
least one downlink transmission beam pattern from among the
plurality of uplink reference signals.
[0026] In accordance with another aspect of the present invention,
an apparatus for tracking a beam by a base station in a wireless
communication system is provided. The apparatus includes a
transmitter for transmitting a plurality of downlink reference
signals to a terminal, and a receiver for receiving, from the
terminal, a plurality of uplink reference signals, each having
identifier information corresponding to at least one downlink
transmission beam pattern determined by the terminal according to
the plurality of downlink reference signals, wherein the
transmitter transmits ACK information indicating that both
identifier information corresponding to an uplink transmission beam
pattern determined according to the plurality of uplink reference
signals and an identifier included in the identifier information
corresponding to the determined at least one downlink transmission
beam pattern have been successfully received.
[0027] In the embodiment, the receiver further receives ACK
information from the terminal upon the terminal successfully
detecting the identifier information corresponding to the uplink
transmission beam pattern, and the transmitter receives Negative
ACKnowledgement (NACK) information from the terminal upon the
terminal not successfully detecting the identifier information
corresponding to the uplink transmission beam pattern.
[0028] In the embodiment, the transmitter further retransmits the
identifier corresponding to the at least one downlink transmission
beam pattern to the terminal upon successfully detecting the
identifier information corresponding to the uplink transmission
beam pattern and upon transmitting Negative ACKnowledgement (NACK)
information indicating that the identifier included in the
identifier information corresponding to the determined at least one
downlink transmission beam pattern has not been successfully
received.
[0029] In the embodiment, the receiver further re-receives a
plurality of uplink reference signals comprising identifier
information corresponding to the determined at least one downlink
transmission beam pattern upon not successfully detecting the
identifier information corresponding to the uplink transmission
beam pattern and upon transmitting Negative ACKnowledgement (NACK)
information indicating that the identifier included in the
identifier information corresponding to the determined at least one
downlink transmission beam pattern has not been successfully
received, and wherein the transmitter retransmits, to the terminal,
ACK information indicating that the identifier included in the
identifier information corresponding to the determined at least one
downlink transmission beam pattern has been successfully received
and retransmits the plurality of uplink reference signals to the
terminal.
[0030] In the embodiment, a wide beam pattern or a previously
received at least one downlink transmission beam pattern is used as
the downlink transmission beam pattern upon receiving NACK
information indicating that the identifier included in the
identifier information corresponding to the determined at least one
downlink transmission beam pattern has not been successfully
received.
[0031] In accordance with another aspect of the present invention,
an apparatus for tracking a beam by a terminal in a wireless
communication system is provided. The apparatus includes a
controller for receiving, from a base station, a plurality of
downlink reference signals to determine at least one downlink
transmission beam pattern, a transmitter for transmitting, to the
base station, identifier information corresponding to at least one
downlink transmission pattern, and a receiver for receiving ACK
information from the base station upon the base station
successfully receiving the identifier information corresponding to
the at least one downlink transmission beam pattern.
[0032] In the embodiment, the transmitter further retransmits the
identifier information corresponding to the determined at least one
downlink transmission beam pattern to the base station using the
determined at least one uplink transmission beam pattern upon not
successfully receiving the identifier information corresponding to
the at least one downlink transmission pattern at the base
station.
[0033] In the embodiment, the transmitter further transmits a
plurality of uplink reference signals to the base station upon the
base station not successfully receiving the identifier information
corresponding to the at least one downlink transmission beam
pattern, wherein the receiver receives, from the base station,
identifier information corresponding to an uplink transmission beam
pattern, and transmits an ACK or a Negative ACKnowledgement (NACK)
according to whether the identifier information corresponding to
the uplink transmission beam pattern is received.
[0034] In accordance with another aspect of the present invention,
an apparatus for tracking a beam by a base station in a wireless
communication system is provided. The apparatus includes a
transmitter for transmitting a plurality of downlink reference
signals to a terminal, and a receiver for receiving, from the
terminal, identifier information corresponding to at least one
downlink transmission beam pattern determined by the terminal
according to the plurality of downlink reference signals, wherein
the transmitter transmits ACK information to the terminal upon
successfully receiving an identifier included in the identifier
information corresponding to the determined at least one downlink
transmission beam pattern.
[0035] In accordance with aspect of the present invention, an
apparatus for tracking a beam by a terminal in a wireless
communication system is provided. The apparatus includes a
transmitter for transmitting a plurality of uplink reference
signals to a base station, and a receiver for receiving, from the
base station, identifier information corresponding to an uplink
transmission beam pattern according to the plurality of uplink
reference signals, wherein the transmitter transmits an ACK or a
NACK according to whether the identifier information corresponding
to the uplink transmission beam pattern is received.
[0036] In the embodiment, the transmitter further retransmits a
plurality of uplink reference signals to the base station upon the
base station not successfully detecting the identifier information
corresponding to the uplink transmission beam pattern, and wherein
the receiver re-receives, from the base station, the identifier
information corresponding to the uplink transmission beam pattern
according to the plurality of uplink reference signals.
[0037] In the embodiment, the controller further receives a
plurality of downlink reference signals from the base station to
determine at least one downlink transmission beam pattern upon the
base station not successfully detecting the identifier information
corresponding to the uplink transmission beam pattern,
[0038] In the embodiment, the transmitter further transmits, to the
base station, identifier information corresponding to the at least
one downlink transmission pattern, and transmits, to the base
station, a plurality of uplink reference signals, and the receiver
receives, from the base station, the identifier information
corresponding to the uplink transmission beam pattern according to
the plurality of uplink reference signals.
[0039] In accordance with another aspect of the present invention
an apparatus for tracking a beam by a base station in a wireless
communication system is provided. The apparatus includes a receiver
for receiving a plurality of uplink reference signals from a
terminal, and a transmitter for transmitting, to the terminal,
identifier information corresponding to an uplink transmission beam
pattern according to the plurality of uplink reference signals,
wherein the receiver receives an ACK or a NACK according to whether
the identifier information corresponding to the uplink transmission
beam pattern is received.
[0040] Other aspects, advantages and salient features of the
invention will become apparent to those skilled in the art from the
following detailed description, which, taken in conjunction with
the annexed drawings, discloses exemplary embodiments of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] The above and other aspects, features, and advantages of
certain exemplary embodiments of the present invention will be more
apparent from the following description taken in conjunction with
the accompanying drawings, in which:
[0042] FIG. 1 illustrates a procedure for simultaneously performing
beam setting for a downlink and an uplink; according to an
exemplary embodiment of the present invention;
[0043] FIG. 2 illustrates a procedure for setting a downlink beam
in case of performing beam setting for a downlink and an uplink;
respectively, according to an exemplary embodiment of the present
invention;
[0044] FIG. 3 illustrates a procedure for setting an uplink beam in
case of performing beam setting for a downlink and an uplink,
respectively, according to an exemplary embodiment of the present
invention;
[0045] FIG. 4 is a flowchart illustrating a process for operating a
terminal performing beam setting for a downlink and an uplink
according to an exemplary embodiment of the present invention;
[0046] FIG. 5 is a flowchart illustrating a process for operating a
base station performing beam setting for a downlink and an uplink
according to an exemplary embodiment of the present invention;
[0047] FIGS. 6A and 6B illustrate a transmission/reception beam
pattern between a base station and a terminal according to an
exemplary embodiment of the present invention;
[0048] FIG. 7 is a block diagram illustrating an apparatus for
setting a beam for a downlink and an uplink according to an
exemplary embodiment of the present invention;
[0049] FIG. 8 is a flowchart illustrating a process for operating a
terminal performing beam setting for a downlink and an uplink
according to an exemplary embodiment of the present invention;
[0050] FIG. 9 is a flowchart illustrating a process for operating a
base station performing beam setting for a downlink and an uplink
according to an exemplary embodiment of the present invention;
[0051] FIG. 10 is a flowchart illustrating a process for operating
a terminal performing beam setting for a downlink and an uplink
according to an exemplary embodiment of the present invention;
and
[0052] FIG. 11 is a flowchart illustrating a process for operating
a base station performing beam setting for a downlink and an uplink
according to an exemplary embodiment of the present invention.
[0053] Throughout the drawings; like reference numerals will be
understood to refer to like parts, components and structures.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0054] The following description with reference to the accompanying
drawings is provided to assist in a comprehensive understanding of
exemplary embodiments of the invention as defined by the claims and
their equivalents. It includes various specific details to assist
in that understanding but these are to be regarded as merely
exemplary. Accordingly, those of ordinary skill in the art will
recognize that various changes and modifications of the embodiments
described herein can be made without departing from the scope and
spirit of the invention. In addition; descriptions of well-known
functions and constructions are omitted for clarity and
conciseness.
[0055] The terms and words used in the following description and
claims are not limited to the bibliographical meanings, but, are
merely used by the inventor to enable a clear and consistent
understanding of the invention. Accordingly, it should he apparent
to those skilled in the art that the following description of
exemplary embodiments of the present invention are provided for
illustration purpose only and not for the purpose of limiting the
invention as defined by the appended claims and their
equivalents.
[0056] It is to be understood that the singular forms "a," "an,"
and "the" include plural referents unless the context clearly
dictates otherwise. Thus, for example, reference to "a component
surface" includes reference to one or more of such surfaces.
[0057] Exemplary embodiments of the present invention provide a
method and an apparatus for tracking a beam in a wireless
communication system.
[0058] Hereinafter, exemplary embodiments describe beam tracking
methods for three methods. However, the present invention is not
limited thereto, and other similar apparatuses and methods for
tracking a beam in a wireless communication system according to the
present invention may be used. A first method is for simultaneously
performing beam setting for a downlink and an uplink. A second
method is for setting a downlink beam in case of respectively
performing beam setting for a downlink and an uplink. In this case,
it is assumed that a terminal knows of Q optimized uplink
transmission beams and a base station knows of one or more
optimized uplink reception beams. A third method is for setting an
uplink beam in case of respectively performing beam setting for a
downlink and an uplink. In this case, it is assumed that abase
station knows of P optimized downlink transmission beams and a
terminal knows of one or more optimized downlink reception
beams.
[0059] FIG. 1 illustrates a procedure for simultaneously performing
beam setting for a downlink and an uplink, according to an
exemplary embodiment of the present invention.
[0060] Referring to FIG. 1, a base station repeatedly transmits a
downlink reference signal, DL reference, N times so that a
terminal, which may also be referred to as a Mobile Station (MS)
may select one or more optimized downlink transmission and/or
reception beams in step 100. Here, N=(Ntx.times.Nrx), wherein Ntx
denotes a number of transmission beams whose direction is changed
and transmitted by the base station, and Nrx denotes a number of
times for which the base station repeatedly transmits a specific
transmission beam for selecting a reception beam of the terminal.
Ntx and Nrx are changeable system information values of which the
base station may inform terminals via a broadcast channel, or any
other suitable means of informing the terminals. The downlink
reference signal may be a signal that may measure quality of a
signal, such as a synchronization signal, a preamble signal, a
pilot signal, or any other similar signal. For example, as
illustrated in FIG. 6A, when the base station can is able to
generate K transmission beam patterns and the terminal is able to
generate L reception beam patterns, the base station should
transmit a total of K*L downlink reference signals to the terminal
during a specific time period.
[0061] Meanwhile, the terminal that has repeatedly received the
downlink reference signal N times measures and selects P optimized
downlink transmission/reception beam pairs via the downlink
reference signal. For example, in FIG. 6A, the terminal may select
one or more downlink transmission/reception beam pairs from among a
total of N*N transmission/reception beam pairs. In FIG. 6A, a
transmission beam #3 of the base station and a reception beam #3 of
the terminal may become an optimized downlink
transmission/reception beam pair.
[0062] After that, the terminal repeatedly transmits an uplink
reference signal. UL Reference, including P optimized downlink
transmission beam index information to the base station a total of
M times in step 102. For example, a sequence corresponding to the
reference signal may be mapped to the downlink transmission beam
index information.
[0063] Here, M=(Mtx.times.Mrx), wherein Mtx denotes a number of
transmission beams whose direction is changed and transmitted by
the terminal, and Mrx denotes a number of times which the terminal
repeatedly transmits a specific transmission beam for selecting a
reception beam of the base station. Mtx and Mrx are changeable
system information values of which the base station may inform
terminals via a broadcast channel, or any other suitable means of
informing the terminal. In addition, assuming downlink/uplink
channel reciprocity, Mtx may be set to 1. The uplink reference
signal denotes a signal that may measure quality of a signal, such
as an access signal, a sounding signal, a pilot signal, or any
other similar signal. For example, as shown in FIG. 6B, when the
terminal is able to generate L transmission beam patterns and the
base station is able to generate K reception beam patterns, the
terminal should transmit N*N uplink reference signals to the base
station during a specific time period.
[0064] According to an implementation, the number of transmission
beam patterns and the number of reception beam patterns of the base
station may be the same or different from each other. Likewise, the
number of transmission beam patterns and the number of reception
beam patterns of the terminal may be the same or different from
each other.
[0065] Meanwhile, when transmitting the uplink reference signal in
step 102, the terminal may control the direction, width, and other
similar physical characteristics, of the uplink transmission beam
according to an ACKnowledgement/Negative ACKnowledgement (ACK/NACK)
response that is transmitted previously by the base station in step
104. For example, when an ACK response is received from the base
station in response to the uplink reference signal transmitted
immediately previously by the terminal, then the terminal may
transmit the uplink reference signal using a narrow beam having a
narrower width than an optimized uplink transmission beam width
that was fed back immediately previously by the base station. When
a NACK response is received in response to the uplink reference
signal transmitted immediately previously by the terminal, the
terminal may transmit the uplink reference signal using a wide beam
that was used for initial transmission.
[0066] The base station measures and selects Q optimized uplink
transmission/reception beam pairs via the uplink reference signal
transmitted by the terminal in step 104. In addition, the base
station detects or decodes an optimized downlink transmission beam
index included in the uplink reference signal. That is, the uplink
reference signal may include a sequence corresponding to a downlink
transmission beam index or a message to which a separate CRC has
been attached.
[0067] In addition, when the base station successfully obtains P
optimized downlink transmission beams and successfully detects or
measures Q optimized uplink transmission beams in step 104, then
the base station transmits Q optimized uplink transmission beam
indexes and transmits ACK information to the terminal via one or
more optimized downlink transmission beams. Here, the ACK
information is transmitted as a response to successfully receiving
P optimized downlink transmission beams transmitted via the uplink
reference signal.
[0068] When the base station fails to receive the P optimized
downlink transmission beams and successfully detects the Q
optimized uplink transmission beams in step 104, then the base
station transmits Q optimized uplink transmission beam indexes and
transmits NACK information to the terminal. Also, the base station
may command the terminal to transmit again P optimized downlink
transmission beam indexes based on the previously received Q
optimized uplink transmission beams.
[0069] Alternatively, when the base station fails to receive the P
optimized downlink transmission beams and also fails to detect the
Q optimized uplink transmission beams in step 104, then the base
station may command the terminal to both transmit NACK information
and perform step 102 again. Alternatively, the terminal may perform
operations from step 102 according to a specific timer without the
command of the base station. However, the present invention is not
limited thereto, and the terminal may perform operations of step
102 according to any suitable reason. Furthermore, depending on
implementation, the ACK/NACK transmission may be omitted in step
104.
[0070] Meanwhile, since the base station cannot know P optimized
downlink transmission beams transmitted by the terminal at a time
point when transmitting NACK, the base station may use a wide beam
or the P optimized downlink transmission beams according to a
previous successful reception. Assuming channel reciprocity for
downlink/uplink, the base station may infer a downlink transmission
beam instead of not detecting a downlink transmission beam by using
one or more optimized uplink reception beams in a limited way.
After that, when the terminal successfully receives Q optimized
uplink transmission beam indexes transmitted by the base station
via the ACK/NACK in step 106, then the terminal stores and updates
a value thereof and transmits an ACK signal to the base
station.
[0071] When the terminal fails to receive the Q optimized uplink
transmission beam indexes transmitted by the base station, then the
terminal transmits a NACK signal in the case where the terminal
recognizes the failure or does not send any signal. In case of
transmitting the NACK, since the terminal cannot know the Q
optimized uplink transmission beams transmitted by the base station
at such a time point, then the terminal may use a wide beam or Q
optimized uplink transmission beams that were previously
successfully received. Assuming channel reciprocity for
downlink/uplink, the terminal may use one or more optimized uplink
reception beams. In addition, when the base station determines that
an ACK/NACK transmitted b the terminal is a NACK in step 106, then
the base station may command the terminal to repeat operations from
step 104.
[0072] FIG. 2 illustrates a procedure for setting a downlink beam
in case of performing beam setting for a downlink and an uplink,
respectively, according to an exemplary embodiment of the present
invention.
[0073] Referring to FIG. 2, a base station repeatedly transmits a
downlink reference signal, DL Reference, N times so that a terminal
may select one or more optimized downlink transmission/reception
beams in step 200. Here, N=(Ntx.times.Nrx), wherein Ntx denotes a
number of transmission beams whose direction is changed and
transmitted by the base station, and Nix denotes a number of times
in which the base station repeatedly transmits a specific
transmission beam for selecting a reception beam of the terminal.
Ntx and Nix are changeable system information values of which the
base station may inform terminals via a broadcast channel, or other
similar channels. The downlink reference signal may be a signal
that can measure quality of a signal, such as a synchronization
signal, a preamble signal, a pilot signal, or other similar
signals.
[0074] At this point, the terminal, which may also be referred to
as a Mobile Station (MS), measures and selects P optimized downlink
transmission/reception beam pairs via a downlink reference signal
in step 200. After that, the terminal transmits P optimized
downlink transmission beam information to the base station via one
or more predetermined uplink transmission beams in step 202. At
this point, the base station detects or decodes the P optimized
downlink transmission beam information. After that, when succeeding
in obtaining the P optimized downlink transmission beam
information, the base station transmits an ACK signal to the
terminal in step 204.
[0075] When failing to obtain the P optimized downlink transmission
beam information, the base station transmits a NACK signal to the
terminal and requests the terminal to re-transmit the P optimized
downlink transmission beam information, i.e., the terminal proceeds
to step 202. According to another exemplary embodiment, when
failing to obtain the P optimized downlink transmission beam
information, the base station may transmit a NACK signal to the
terminal, and perform steps 102 to 106 of FIG. 1. According to
another exemplary embodiment, the base station may perform the
operations of FIG. 3, as discussed below, and then perform steps
200 to 204 of FIG. 2,
[0076] FIG. 3 illustrates a procedure for setting an uplink beam in
case of respectively performing beam setting for a downlink and an
uplink, according to an exemplary embodiment of the present
invention.
[0077] Referring to FIG. 3, a terminal repeatedly transmits an
uplink reference signal, UL Reference, to a base station N times in
step 300. Here, M=(Mtx.times.Mrx_, wherein Mtx denotes the number
of transmission beams whose direction is changed and transmitted by
the terminal, and Mrx denotes the number of times which the
terminal repeatedly transmits a specific transmission beam for
selecting a reception beam of the base station. Mtx and Mrx are
changeable system information values of which the base station may
inform terminals via a broadcast channel, or any other suitable
channel. In addition, assuming downlink/uplink channel reciprocity,
Mtx may be set to 1. The uplink reference signal denotes a signal
that may measure quality of a signal, such as an access signal, a
sounding signal, a pilot signal, or any other similar channel.
[0078] When transmitting an uplink reference signal, the terminal
may control the direction, the width, or other similar physical
characteristics, of an uplink transmission beam based on an
ACK/NACK response transmitted by the base station in FIG. 2. For
example, in the case where an ACK response is received in response
to a beam index feedback signal transmitted by the terminal during
a previous downlink beam tracking process, i.e., step 204 of FIG.
2, the terminal may transmit an uplink reference signal using a
beam having a smaller width and a time and improved gain based on
an optimized uplink transmission beam fed back by a base station
during a previous uplink beam tracking process. In the case where
the NACK response is received in response to a beam index feedback
signal transmitted by the terminal during a previous downlink beam
tracking process, i.e., step 204 of FIG. 2, the terminal may
transmit an uplink reference signal using a beam having a wide
width that is used for an initial transmission.
[0079] At this point, the base station measures and selects Q
optimized uplink transmission/reception beam pairs via an uplink
reference signal. After that, when succeeding in measuring the Q
optimized uplink transmission/reception beams in step 300, the base
station transmits Q optimized uplink transmission beam information
together with ACK information to a terminal using one or more
optimized downlink transmission beams in step 302. When failing to
measure the Q optimized uplink transmission/reception beams, that
is, in the case where a size of the uplink reference signal cannot
exceed a predetermined specific threshold, in step 300, then the
base station may command the terminal to perform step 300 again
together with transmitting the NACK information. However, the
present invention is not limited thereto, and ACK/NACK information
transmission may be omitted.
[0080] After that, when successfully receiving the Q optimized
uplink transmission beam information transmitted by the base
station, the terminal stores and updates a value thereof and sends
an ACK signal to the base station in step 304. When failing to
receive the Q optimized uplink transmission beam information, the
terminal sends a NACK signal in the case where the terminal
recognizes the failure or does not send any signal. At this point,
when receiving the NACK signal sent from the terminal or when the
base station determines a NACK was sent, the base station proceeds
to step 302 to re-perform subsequent steps. According to an
exemplary embodiment, when receiving a NACK response from the
terminal or when the base station determines the NACK was sent, the
base station performs steps 200 to 204 of FIG. 2, and then performs
steps 300 to 304 of FIG. 3.
[0081] FIG. 4 is a flowchart illustrating a process for operating a
terminal performing beam setting for a downlink and an uplink
according to an exemplary embodiment of the present invention.
[0082] Referring to :FIG. 4, a terminal receives a downlink
reference signal from a base station N times in step 400. Here,
N=(Ntx.times.Nrx), wherein Ntx denotes a number of transmission
beams whose direction is changed and transmitted by the base
station, and Nrx denotes a number of times for which the base
station repeatedly transmits a specific transmission beam for
selecting a reception beam of the terminal. Ntx and Nrx are
changeable system information values of which the base station may
inform terminals via a broadcast channel, or another similar
channel. The downlink reference signal may be a signal that may
measure quality of a signal, such as a synchronization signal, a
preamble signal, a pilot signal, or other similar signal.
[0083] For example, as in FIG. 6A, when the base station is able to
generate K transmission beam patterns and the terminal is able to
generate L reception beam patterns, the base station may transmit a
total of K*L downlink reference signals to the terminal during a
specific time section. After that, the terminal that has received
the downlink reference signal N times measures and selects P
optimized downlink transmission/reception beam pairs via the
downlink reference signal in step 402. For example, in FIG. 6A, the
terminal may select at least one downlink transmission/reception
beam pair from among N*N transmission/reception beam pairs. In FIG.
6A, a transmission beam 43 of the base station and a reception beam
43 of the terminal may become an optimized downlink
transmission/reception beam pair.
[0084] After that, the terminal repeatedly transmits an uplink
reference signal that includes P optimized transmission beam index
information to the base station M times in step 404. For example, a
sequence corresponding to the reference signal may be mapped to
transmission beam index information. Here, M=(Mtx.times.Mrx). Mtx
denotes the number of transmission beams whose direction is changed
and transmitted by the terminal, and Mrx denotes the number of
times for which the terminal repeatedly transmits a specific
transmission beam for selecting a reception beam of the base
station. Mtx and Mrx are changeable system information values of
which the base station may inform terminals via a broadcast
channel, or other similar channels. In addition, assuming
downlink/uplink channel reciprocity, Mtx may be set to 1. The
uplink reference signal denotes a signal that may measure quality
of a signal, such as an access signal, a sounding signal, a pilot
signal, or any other suitable signal.
[0085] For example, as shown in FIG. 6B, when the terminal is able
to generate L transmission beam patterns and the base station is
able to generate K reception beam patterns, the terminal may
transmit a total of K*L uplink reference signals to the base
station during a specific time section. According to an exemplary
embodiment of the present invention, a number of transmission beam
patterns and a number of reception beam patterns of the base
station may be the same or different from each other. Likewise, the
number of transmission beam patterns and the number of reception
beam patterns of the terminal may be the same or different from
each other.
[0086] Meanwhile, when transmitting the uplink reference signal,
the terminal may control the direction, width, or other similar
physical characteristics of the uplink transmission beam according
to an ACK/NACK response transmitted previously by the base station.
For example, when an ACK response is received from the base station
in response to the uplink reference signal transmitted immediately
previously by the terminal, the terminal may transmit the uplink
reference signal using a narrow beam having a narrower width than
an optimized uplink transmission beam width that was fed back
immediately previously by the base station. When a NACK response is
received in response to the uplink reference signal transmitted
immediately previously by the terminal, the terminal may transmit
the uplink reference signal using a wide beam used for initial
transmission.
[0087] After that, when an optimized downlink transmission beam
index that is included in the uplink reference signal is
successfully detected by the base station and Q uplink transmission
beams are successfully detected according to the uplink reference
signal in step 406, then the terminal proceeds to step 408 to
receive Q uplink transmission beam indexes from the base station.
When the reception of P optimized downlink transmission beams by
the base station fails and the detection of the Q optimized uplink
transmission beams also fails in step 406, then the terminal
proceeds to step 404 to re-transmit an uplink reference signal
including P optimized transmission beam index information to the
base station M times. In another implementation, when the reception
of the P optimized downlink transmission beams by the base station
fails and the detection of the Q optimized uplink transmission
beams also fails in step 406, then the terminal proceeds to step
400 to receive and process a downlink reference signal again.
[0088] According to an exemplary embodiment, when the reception of
P optimized downlink transmission beams by the base station fails
and the Q optimized uplink transmission beams are successfully
detected, then the terminal re-transmits optimized downlink
transmission beam indexes to the base station according to the
previous Q optimized uplink transmission beams. After that, when
successfully receiving Q optimized uplink transmission beam indexes
transmitted by the base station in step 410, the terminal proceeds
to step 412 to store and update a value thereof and sends an ACK
signal to the base station. Furthermore, when failing to receive
the Q optimized uplink transmission beam indexes transmitted by the
base station, the terminal proceeds to step 408 to transmit an NACK
signal, such as in the case where the terminal recognizes the
failure or does not send any signal. At this point, the terminal
proceeds to step 406 to re-request the base station to transmit Q
optimized uplink transmission beam indexes and receive the
same.
[0089] FIG. 5 is a flowchart illustrating a process for operating a
base station performing beam setting for a downlink and an uplink
according to an exemplary embodiment of the present invention.
[0090] Referring to FIG. 5, the base station repeatedly transmits a
downlink reference signal N times so that a terminal may select one
or more optimized downlink transmission/reception beams in step
500. Here, N=(Ntx.times.Nrx), wherein Ntx denotes a number of
transmission beams whose direction is changed and transmitted by
the base station, and Nrx denotes a number of times which the base
station repeatedly transmits a specific transmission beam for
selecting a reception beam of the terminal. Mrx and Nrx are
changeable system information values of which the base station may
inform terminals via a broadcast channel, or any other similar
channel. The downlink reference signal may be a signal that may
measure quality of a signal, such as a synchronization signal, a
preamble signal, a pilot signal, or any other similar signal.
[0091] For example, as illustrated in FIG. 6A, when the base
station is able to generate K transmission beam patterns and the
terminal is able to generate L reception beam patterns, the base
station may transmit K*L downlink reference signals in total to the
terminal during a specific time section.
[0092] After that, the base station receives an uplink reference
signal, including P optimized transmission beam index information,
from the terminal over M times to measure and select Q optimized
uplink transmission/reception beam pairs via an uplink reference
signal that is transmitted by the terminal in step 502. For
example, a sequence corresponding to the reference signal may be
mapped to the transmission beam index information. Here,
M=(Mtx.times.Mrx), wherein Mtx denotes the number of transmission
beams whose direction is changed and transmitted by the terminal,
and Mrx denotes the number of times for which the terminal
repeatedly transmits a specific transmission beam for selecting a
reception beam of the base station. Mtx and Mrx are changeable
system information values of which the base station may inform
terminals via, a broadcast channel, or other similar channel. In
addition, assuming downlink/uplink channel reciprocity, Mtx may be
set to 1. The uplink reference signal denotes a signal that may
measure quality of a signal, such as an access signal, a sounding
signal, a pilot signal, or other similar signal.
[0093] For example, as shown in FIG. 6B, when the terminal is able
to generate K transmission beam patterns and the base station is
able to generate L reception beam patterns, the terminal should
transmit K*L uplink reference signals to the base station during a
specific time section. According to an exemplary embodiment, the
number of transmission beam patterns and the number of reception
beam patterns of the base station may be the same or different from
each other. Likewise, the number of transmission beam patterns and
the number of reception beam patterns of the terminal may be the
same or different from each other.
[0094] After that, the base station determines whether Q optimized
uplink transmission beams are successfully detected in step 504.
After the Q optimized uplink transmission beams are successfully
detected, the base station determines whether P optimized downlink
transmission beams are successfully detected. When the P optimized
downlink transmission beams are successfully detected, the base
station proceeds to step 508 to transmit Q optimized uplink
transmission beam indexes and to transmit ACK information to the
terminal via one or more optimized downlink transmission beams.
Here, the ACK information is in response to successfully receiving
P optimized downlink transmission beams transmitted via the uplink
reference signal.
[0095] When failing to receive the P optimized downlink
transmission beams and successfully detecting the Q optimized
uplink transmission beams in step 506, the base station proceeds to
step 510 to transmit the Q optimized uplink transmission beam
indexes and NACK information to the terminal. Also, the base
station may command the terminal to re-transmit the P optimized
downlink transmission beam indexes to the terminal according to the
previously received Q optimized uplink transmission beams.
[0096] Alternatively,when failing to receive the P optimized
downlink transmission beams in step 506 and also failing to detect
the Q optimized uplink transmission beam in step 504, then the base
station proceeds to step 502 to re-receive, for M times, an uplink
reference signal including P optimized transmission beam index
information from the terminal to measure and select Q optimized
uplink transmission/reception beam pairs via an uplink reference
signal transmitted by the terminal. According to an exemplary
embodiment, when failing to receive the P optimized downlink
transmission beams in step 506 and also failing to detect the Q
optimized uplink transmission beam in step 504, the base station
proceeds to step 500 to restart from the downlink reference signal
transmission step.
[0097] After that, when successfully receiving Q optimized uplink
transmission beam indexes transmitted by the terminal in step 512,
the base station ends the procedure of the present invention. When
failing to receive the Q optimized uplink transmission beam indexes
transmitted by the terminal, the base station proceeds to step 508
to retransmit Q uplink transmission beam indexes to the
terminal.
[0098] FIG. 7 is a block diagram illustrating an apparatus for
setting a beam for a downlink and an uplink according to an
exemplary embodiment of the present invention.
[0099] Referring to FIG. 7, a terminal includes a controller 700, a
receiver 702, and a transmitter 704. Likewise, a base station
includes a controller 710, a receiver 714, and a transmitter 712.
The receivers 702 and 714 perform baseband signal-processing on a
Radio Frequency (RF) signal received via a plurality of
antennas.
[0100] For example, in case of using an OFDM scheme, the receiver
converts an analog signal into sample data, and performs a Fast
Fourier Transform (ITT) on the sample data to transform the sample
data into data in a frequency domain, and selects data of
subcarriers, which the receiver actually desires, to receive from
the data in the frequency domain, and outputs the same. In
addition, the receiver demodulates and decodes the data according
to a predetermined Modulation and Coding Scheme (MCS) level to
provide the decoded data to the controller 700 and 710. For another
example, in case of using a CDMA scheme, the receiver 702 and 714
may channel-decode and despread the data.
[0101] The transmitters 704 and 712 convert baseband signal into an
RF signal and transmits the RF signal. For example, the
transmitters 704 and 712 encode and modulate data respectively
received from the controllers 700 and 710 according to a
predetermined MCS level. In addition, the transmitters 704 and 714
perform Inverse Fast Fourier Transform (TFFT) on a modulated symbol
to output sample data, such as an OFDM symbol, converts the sample
data into an analog signal, converts the analog signal into an RF
signal, and outputs the RF signal via an antenna. For another
example, the transmitter 704 and 712 may channel-code and spread
data to be transmitted.
[0102] In the above configuration, the controllers 700 and 710 may
serve as protocol controllers. The controller 700 controls an
overall operation of the terminal. The controller 710 controls an
overall operation of the base station. In addition, the controllers
700 and 710 receive required information from relevant portions of
a physical layer while performing a protocol process, or generate a
control signal for the relevant portion of the physical layer. In
addition, the controllers 700 and 710 determine beam tracking and
transmission/reception beam-forming patterns. That is, the
controllers 700 and 710 control the operation of the terminal and
the base station, as described in FIGS. 1 to 3.
[0103] For example, according to an exemplary embodiment, the
controller 700 of the terminal receives a plurality of downlink
reference signals from the base station to determine at least one
downlink transmission beam pattern, transmits a plurality of uplink
reference signals including index information corresponding to the
determined at least one downlink transmission beam pattern to the
base station, and receives ACK information indicating that an index
corresponding to the at least one downlink transmission beam
pattern has been successfully received in the base station from
index information corresponding to an uplink transmission beam
pattern and the plurality of uplink reference signals from the base
station.
[0104] In addition, when successfully detecting index information
corresponding to the uplink transmission beam pattern, as received
from the base station, the controller 700 of the terminal transmits
ACK information to the base station. When not successfully
detecting the index information corresponding to the uplink
transmission beam pattern, as received from the base station, the
controller 700 of the terminal transmits NACK information to the
base station. When successfully detecting index information
corresponding to an uplink transmission beam pattern and receiving
NACK information indicating that an index corresponding to the at
least one downlink transmission beam pattern has not been
successfully received in the base station from the plurality of
uplink reference signals, the controller 700 of the terminal
re-receives an index corresponding to at least one downlink
transmission beam pattern from the base station based on a
plurality of previous uplink transmission beam patterns.
[0105] Meanwhile, when not successfully detecting index information
corresponding to an uplink transmission beam pattern from the base
station and receiving NACK information indicating that an index
corresponding to at least one downlink transmission beam pattern
has not been successfully received in the base station from the
plurality of uplink reference signals, the controller 700 of the
terminal retransmits, to the base station, a plurality of uplink
reference signals that include index information corresponding to
the determined at least one downlink transmission beam pattern.
Also, the controller 700 of the terminal further re-receives ACK
information indicating that the index corresponding to the at least
one downlink transmission beam pattern has been successfully
received in the base station from the index information
corresponding to the uplink transmission beam pattern and the
plurality of uplink reference signals from the base station.
[0106] Furthermore, when the controller receives the NACK
information indicating that the index corresponding to the at least
one downlink transmission beam pattern has not been successfully
received in the base station from the plurality of uplink reference
signals, a wide beam pattern or a previously received at least one
downlink transmission beam pattern is used as the downlink
transmission beam pattern.
[0107] According to an exemplary embodiment of the present
invention, the controller 710 of the base station transmits a
plurality of downlink reference signals to the terminal, receives a
plurality of uplink reference signals, including index information
corresponding to at least one downlink transmission beam pattern
determined by the terminal, from the terminal according to the
plurality of downlink reference signals, and transmits ACK
information indicating that index information corresponding to an
uplink transmission beam pattern determined based on the plurality
of uplink reference signals and an index corresponding to the at
least one downlink transmission beam pattern have been successfully
received.
[0108] Also, upon successfully detecting index information
corresponding to the uplink transmission beam pattern via the
terminal, the controller 710 of the base station receives ACK
information from the terminal. Upon not successfully detecting the
index information corresponding to the uplink transmission beam
pattern via the terminal, the controller 710 of the base station
receives NACK information from the terminal.
[0109] Meanwhile, when successfully detecting the index information
corresponding to the uplink transmission beam pattern and
transmitting NACK information indicating that the index
corresponding to the at least one downlink transmission beam
pattern has not been successfully received from the plurality of
uplink reference signals, the controller 710 of the base station
re-transmits an index corresponding to the at least one downlink
transmission beam pattern to the terminal according to the
plurality of previous uplink transmission beam patterns.
[0110] Upon not successfully detecting index information
corresponding to an uplink transmission beam pattern and
transmitting NACK information indicating that the index
corresponding to the at least one downlink transmission beam
pattern has not been successfully received from the plurality of
uplink reference signals, then the controller 710 of the base
station re-receives a plurality of uplink reference signals
including index information corresponding to the determined at
least one downlink transmission beam pattern, and then retransmits
ACK information indicating that an index corresponding to the at
least one downlink transmission beam pattern has been successfully
received from index information corresponding to an uplink
transmission beam pattern and the plurality of uplink reference
signals to the terminal.
[0111] At this point, upon receiving NACK information indicating
that an index corresponding to the at least one downlink
transmission beam pattern has not been successfully received from
the plurality of uplink reference signals, a wide beam pattern or a
previously received at least one downlink transmission beam pattern
may be used as the downlink transmission beam pattern.
[0112] According to an exemplary embodiment of the present
invention, the controller 700 of the terminal determines one or
more uplink transmission beam patterns and one or more uplink
reception beam patterns, and also receives a plurality of downlink
reference signals from the base station to determine at least one
downlink transmission beam pattern. Furthermore, the controller 700
transmits index information corresponding to at least one downlink
transmission pattern to the base station using the determined at
least one uplink transmission beam pattern, and when index
information corresponding to the at least one downlink transmission
beam pattern is successfully received by the base station, the
controller 700 of the terminal receives ACK information from the
base station.
[0113] At this point, when the index information corresponding to
the at least one downlink transmission beam pattern is not
successfully received by the base station, the controller 700 of
the terminal retransmits index information corresponding to at
least one downlink transmission beam pattern to the base station
using the determined at least one uplink transmission beam
pattern.
[0114] When the index information corresponding to the at least one
downlink transmission beam pattern is not successfully received by
the base station, the controller 700 of the terminal transmits a
plurality of uplink reference signals to the base station, receives
index information corresponding to an uplink transmission beam
pattern from the base station, and transmits an ACK or a NACK
according to whether index information corresponding to the uplink
transmission beam pattern is received.
[0115] According to an exemplary embodiment of the present
invention, the controller 710 of the base station determines one or
more uplink transmission beam patterns and one or more uplink
reception beam patterns, and also transmits a plurality of downlink
reference signals. The controller 710 also receives index
information corresponding to at least one downlink transmission
beam pattern determined by the terminal based on the plurality of
downlink reference signals from the terminal, and when an index
corresponding to the at least one downlink transmission beam
pattern is successfully received, the controller 710 transmits ACK
information to the terminal.
[0116] According to an exemplary embodiment of the present
invention, the controller 700 of the terminal determines one or
more downlink transmission beam patterns and one or more downlink
reception beam patterns, transmits a plurality of uplink reference
signals to the base station, receives index information
corresponding to an uplink transmission beam pattern according to
the plurality of uplink reference signals from the base station,
and transmits an ACK or a NACK according to whether the index
information corresponding to the uplink transmission beam pattern
is received.
[0117] Also, when index information corresponding to an uplink
transmission beam pattern is not successfully detected by the base
station, the controller 700 of the terminal retransmits a plurality
of uplink reference signals to the base station and re-receives the
index information corresponding to the uplink transmission beam
pattern based on the plurality of uplink reference signals from the
base station. Additionally, when the index information
corresponding to the uplink transmission beam pattern is not
successfully detected by the base station, the controller 700 of
the terminal receives a plurality of downlink reference signals
from the base station to determine at least one downlink
transmission beam pattern, transmits the index information
corresponding to the at least one downlink transmission pattern to
the base station, transmits a plurality of uplink reference signals
to the base station, and receives index information corresponding
to an uplink transmission beam pattern according to the plurality
of uplink reference signals from the base station.
[0118] According to an exemplary embodiment of the present
invention, the controller 710 of the base station determines one or
more downlink transmission beam patterns and one or more downlink
reception beam patterns, receives a plurality of uplink reference
signals from the terminal, transmits index information
corresponding to an uplink transmission beam pattern to the
terminal based on the plurality of uplink reference signals, and
receives an ACK or a NACK according to whether the index
information corresponding to the uplink transmission beam pattern
is received.
[0119] FIG. 8 is a flowchart illustrating a process for operating a
terminal performing beam setting for a downlink and an uplink
according to an exemplary embodiment of the present invention.
[0120] Referring to FIG. 8, the terminal determines one or more
uplink transmission beam patterns and one or more uplink reception
beam patterns, and receives a plurality of downlink reference
signals in step 800. After that, the terminal determines at least
one downlink transmission beam pattern based on a received downlink
reference signal, and transmits index information corresponding to
at least one downlink transmission pattern to the base station
using the determined one or more uplink transmission beam patterns
in step 802. After that, when index information corresponding to
the at least one downlink transmission beam pattern is not
successfully received by the base station in step 804, the terminal
proceeds to step 802 to retransmit index information corresponding
to at least one downlink transmission beam pattern to the base
station using the determined at least one uplink transmission beam
pattern.
[0121] According to an exemplary embodiment, when index information
corresponding to the at least one downlink transmission beam
pattern is not successfully received by the base station, the
terminal transmits a plurality of uplink reference signals to the
base station, receives index information corresponding to an uplink
transmission beam pattern from the base station, and transmits an
ACK or a NACK according to whether the index information
corresponding to the uplink transmission beam pattern is received.
In contrast, when receiving ACK information from the base station
in response to transmission of at least one downlink transmission
beam index in step 804, the terminal ends the beam tracking
procedure of the present invention.
[0122] FIG. 9 is a flowchart illustrating a process for operating a
base station performing beam setting for a downlink and an uplink
according to an exemplary embodiment of the present invention.
[0123] Referring to FIG. 9, the base station determines one or more
uplink transmission beam patterns and one or more uplink reception
beam patterns and then transmits a plurality of downlink reference
signals to a terminal in step 900. Next, in step 902, the base
station receives, from the terminal, index information
corresponding to at least one downlink transmission beam pattern as
determined by the terminal based on the plurality of downlink
reference signals.
[0124] After that, upon successfully detecting index information
corresponding to a downlink transmission beam pattern in step 904,
the base station proceeds to step 906 to transmit ACK information
to the terminal. On the other hand, when not successfully detecting
the index information corresponding to the downlink transmission
beam pattern in step 904, the base station proceeds to step 908 to
transmit NACK information to the terminal and then proceeds to step
910 to re-receive index information corresponding to at least one
downlink transmission beam pattern from the terminal.
[0125] FIG. 10 is a flowchart illustrating a process for operating
a terminal performing beam setting for a downlink and an uplink
according to an exemplary embodiment of the present invention.
[0126] Referring to FIG. 10, the terminal determines one or more
downlink transmission beam patterns and one or more downlink
reception beam patterns, and then transmits a plurality of uplink
reference signals to the base station in step 1000. After that, the
terminal receives index information corresponding to an uplink
transmission beam pattern from the base station based on the
plurality of uplink reference signals in step 1002.
[0127] After that, the terminal determines whether index
information corresponding to an uplink transmission beam pattern
has been successfully received in step 1004. When the index
information corresponding to the uplink transmission beam pattern
has been successfully received, the terminal proceeds to step 1006
to transmit an ACK message. On the other hand, when it is
determined that the index information corresponding to the uplink
transmission beam pattern has not been successfully received at
step 1004, then the terminal transmits NACK in step 1008, and
retransmits a plurality of uplink reference signals to the base
station. Next, the terminal proceeds to step 1010 and re-receives
index information corresponding to an uplink transmission beam
pattern from the base station based on the plurality of uplink
reference signals.
[0128] According to another exemplary embodiment, when index
information corresponding to an uplink transmission beam pattern is
not successfully received by the base station, then the terminal
receives a plurality of downlink reference signals from the base
station to determine at least one downlink transmission beam
pattern. Furthermore, the base station then transmits index
information corresponding to the at least one downlink transmission
pattern to the base station, transmits a plurality of uplink
reference signals to the base station, and receives index
information corresponding to an uplink transmission beam pattern
from the base station based on the plurality of uplink reference
signals. /
[0129] FIG. 11 is a flowchart illustrating a process for operating
a base station performing beam setting for a downlink and an uplink
according to an exemplary embodiment of the present invention.
[0130] Referring to FIG. 11, the base station determines one or
more downlink transmission beam patterns and one or more downlink
reception beam patterns, and receives a plurality of uplink
reference signals from a terminal in step 1100. After that, in step
1102, the base station transmits index information corresponding to
an uplink transmission beam pattern to the terminal based on the
plurality of uplink reference signals.
[0131] After that, when it is determined in step 1104 that an ACK
message is received in response to index information corresponding
to the uplink transmission beam pattern, the base station ends the
beam tracking procedure of the present invention. On the other
hand, when receiving a NACK message in response to the index
information corresponding to the uplink transmission beam pattern,
i.e., when it is determined in step 1104 that an ACK message is not
received, then the base station proceeds to step 1102 to retransmit
the index information corresponding to at least one downlink
transmission beam pattern to the terminal.
[0132] As described above, when an index corresponding to a
downlink transmission/reception beam pattern and an index
corresponding to an uplink transmission/reception beam pattern are
received, an index retransmission procedure corresponding to a
transmission/reception beam pattern is defined, so that a wireless
communication system may efficiently select a
transmission/reception beam-forming pattern.
[0133] While the invention has been shown and described with
reference to certain exemplary embodiments thereof, it will be
understood by those skilled in the art that various changes in form
and details may be made therein without departing from the spirit
and scope of the invention as defined b the appended claims and
their equivalents.
* * * * *