Title of Invention

METHOD FOR TRANSCEIVING A SIGNAL IN WIRELESS COMMUNICATION SYSTEM

Abstract A method of transmitting a signal using a prescribed frame structure in a wireless communication system is disclosed. A mobile station is able to transmit or receive a signal using a frame structure with a CP length corresponding to 1/4 of a useful symbol. Moreover, the mobile station is able to transmit or receive a signal using a frame structure with a CP length corresponding to 1/4 of a useful symbol, which is designed to mutually coexist without causing collision or interference with another frame structure with a different CP length. In this case, a channel bandwidth of the prescribed frame structure is 8.75 MHz.
Full Text METHOD FOR TRANSCEIVING A SIGNAL IN WIRELESS COMMUNICATION
SYSTEM
CROSS-REGERENCE TO RELATED APPLICATIONS
[0001] Pursuant to 35 U.S.C. ยง 119(e), this application claims the benefit of priority
to Provisional Application No. 61/166,252, filed on April 03, 2009, Provisional Application
No. 61/173,214, filed on April 28, 2009, Provisional Application No. 61/218,047, filed on
June 17, 2009, and Korean application No. 10-2009-0067849, filed on July 24, 2009, the
contents of which are incorporated by reference herein in their entirety.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention relates to a signal transmitting method, and more
particularly, to a method of transmitting a signal in a wireless communication system using
a prescribed frame structure.
Discussion of the Related Art
[0003| Generally, IEEE 802.16m system is able to support FDD (frequency
division duplex) including H-FDD (half-frequency division duplex) mobile station
operation and TDD time division duplex) both. The IEEE 802.16m system uses OFDMA
(orthogonal frequency division multiplexing access) as a multiple access scheme in DL
(downlink) and UL (uplink). Contents for OFDMA parameters are shown in Table 1.
[0004] [Table 1]
[0005] In the following description, a frame structure of the IEEE 802.16m system
is schematically explained.
[0006] FIG. 1 is a diagram of a basic frame structure in IEEE 802.16m system.
[0007] Referring to FIG. 1, each 20ms super frame is divided into four 5ms radio
frames equal to each other in size. And, the corresponding super frame starts with a super
frame header (SFH). In case of using the same OFDMA parameters of Table 1 within a
channel bandwidth selected from 5MHz, 10MHz and 20MHz, each of the 5ms radio frames
is constructed with eight subframes. One subframe can be allocated for downlink or uplink
transmission. A first type can be defined as a subframe including 6 OFDMA symbols. A
second type can be defined as a subframe including 7 OFDMA symbols. And, a third type
can be defined as a subframe including 5 OFDMA symbols.
[0008] A basic frame structure is applicable to FDD including H-FDD mobile
station operation and TOD both. The number of switching points in each radio frame of
TDD system is 2. The switching point can be defined according to a change of directionality
from downlink to uplink or uplink to downlink.
[0009] H-FDD mobile station can be included in FDD system. A frame structure in
viewpoint of the H-FDD mobile station is similar to a TDD frame structure. Yet, downlink
and uplink transmissions occur in two individual frequency bands. Transmission gaps
between downlink and uplink (and vice versa) are requested to switch transmitting and
receiving circuits to each other.
fOOlOJ FrG. 2 is a diagram for an example of TDD frame having a DL-to-UL ratio
set to 5:3.
[0011] Referring to FIG. 2, assuming that an OFDMA symbol duration is 102.857
u.s and that a CP (cyclic prefix) length is set to a length corresponding to 1/8 of a useful
symbol length (Tu), lengths of first and second type subframes are 0.617 ms and 0.514 ms,
respectively. A last DL (downlink) subframe SF4 is a subframe of a third type. And, a TTG
(transmit transition gap) and an RTG (receive transition gap) are set to 105.714 u.s and 60 u.s,
respectively. According to another numerology, the number of subframes per frame and the
number of symbols within a subframe may be different.
[0012] FIG. 3 is a diagram for an example of a frame structure in FDD system.
[0013] Referring to FIG. 3, a base station supporting FDD system is able to
simultaneously support half-duplex mobile station operating with a same RF carrier and a
full-duplex mobile station both. A mobile station supporting FDD system should use either
H-FDD system or FDD system. All subframes are available for both DL and UL
transmissions. The DL and UL transmissions can be discriminated from each other in
frequency domain. One super frame is divided into 4 frames. And, one of the frames
includes 8 subframes.
[0014] FIG. 4 is a diagram for TDD and FDD frame structures with CP length
corresponding to 1/16 of a useful symbol length (Tu).
[0015] Referring to FIG. 4, a frame of IEEE 802.16m system, which has a CP
length corresponding to 1/16 of a useful symbol length (Tu) for channel bandwidths of
5MHz. 10MHz and 20MHz, includes 5 first type subframes and 3 second type subframes in
FDD system or includes 6 first type subframes and 2 second type subframes in TDD system.
[0016] Assuming that an OFDMA symbol duration is 97.143 us and that a CP
(cyclic prefix) length is set to a length corresponding to 1/16 of a useful symbol length (Tu),
lengths of the first and second type subframes are 0.583 ms and 0.680 ms, respectively. And,
a TTG (transmit transition gap) and an RTG (receive transition gap) are set to 82.853 us and
60 us, respectively. According to another numerology, the number of subframes per frame
and the number of symbols within a subframe may be different.
[0017) As mentioned in the foregoing description, in the IEEE 802.16m system,
OFDMA parameters and frame structures for channel bandwidths of 5MHz, 10MHz and
20MHz are only defined for a case that a CP length is 1/8 Tb and a case that a CP length is
1/16 Tb. Namely, a frame structure for a case that a CP length is 1/4 Tb has not been
proposed so far.
[0018] A frame structure with a CP length of 1/4 Tb may cause a problem with a
previous frame structure with a CP length of 1/8 or 1/16 Tb that interference is generated
from a switching point between downlink and uplink. However, a new frame structure
enabling mutual co-existence by solving this problem has not been proposed so far.
[0019] In the IEEE 802.16m system, OFDMA parameters and frame structures of
1/8 Tb and 1/16 Tb are defined for 8.75 MHz band only but definition has not been made
for 1/4 Tb yet. When a frame structure with a CP length of 1/4 Tb is used, if an idle interval
for TTG/RTG is set in a conventional manner, it may cause a problem that this interval
becomes smaller than TTG/RTG of a frame structure with a different CP length (1/8 Tb or
1/16 Tb). Therefore, this problem needs to be solved.
SUMMARY OF THE INVENTION
[0020] Accordingly, the present invention is directed to a method of transmitting a
signal in a wireless communication system that substantially obviates one or more problems
due to limitations and disadvantages of the related art.
[0021] An object of the present invention is to provide a method of transmitting a
signal in a wireless communication system.
[0022] Additional advantages, objects, and features of the invention will be set
forth in part in the description which follows and in part will become apparent to those
having ordinary skill in the art upon examination of the following or may be learned from
practice of the invention. The objectives and other advantages of the invention may be
realized and attained by the structure particularly pointed out in the written description and
claims hereof as well as the appended drawings.
[0023] To achieve these objects and other advantages and in accordance with the
purpose of the invention, as embodied and broadly described herein, a method for
transceiving a signal using a frame structure in a wireless communication system, the
method includes the steps of transceiving a signal through a frame according to the frame
structure, wherein the frame comprises 6 subframes, and the 6 subframes comprise at least
one of a first type subframe including 6 OFDMA (orthogonal frequency division multiple
access) symbols or a second type subframe including 7 OFDMA symbols.
[0024] Preferably, the frame is a TDD (time division duplex) frame or an FDD
(frequency division duplex) frame.
[0025] More preferably, the TDD frame includes a downlink interval and an uplink
interval subsequent to the downlink interval, and the wherein the first type subframe is
located at a first downlink subframe of the downlink interval and a first uplink subframe of
the uplink interval.
[0026] In this case, the second type subframe is located at a second downlink
subframe of the downlink and a second uplink subframe of the uplink interval.
[0027] And, a TTG (transmit transition gap) is located between the downlink
interval and the uplink interval in the TDD frame, and wherein an RTG (receive transition
gap) is located next to a last subframe of the uplink interval in the TDD frame. Moreover,
the TDD frame includes 4 first type subframes and 2 second type subframes. Besides, a
ratio of a number of DL subframes to a number of UL subframes in the TDD frame is set to
one of5:l, 4:2, 3:3 and 2:4.
[0028] More preferably, the second type subframe in the FDD frame is located in
the same order of a last downlink subframe located in the TDD frame.
[0029] In this case, the second type subframe is located at a fourth subframe in the
FDD frame. And, the FDD frame includes 3 first type subframes and 3 second type
subframes. Moreover, an idle time is located next to a last subframe in the FDD frame.
[0030] Preferably, the frame comprises a CP (cyclic prefix), a length of the CP is
set to 1/4 of a useful symbol length.
[0031] Preferably, a channel bandwidth of the frameis set to 8.75 MHz.
[0032] In another aspect of the present invention, a apparatus for transceiving a
signal using a frame structure in a wireless communication system, the apparatus includes
transceiving module for transceiving a signal through a frame according to the frame
structure, wherein the frame comprises 6 subframes, and the 6 subframes comprise at least
one of a first type subframe including 6 OFDMA (orthogonal frequency division multiple
access) symbols or a second type subframe including 7 OFDMA symbols.
[0033) Accordingly, the present invention provides the following effects and/or
advantages.
[0034] First of all, the present invention enables a signal to be transmitted/received
using a TDD frame structure with a CP length corresponding to 1/4 of a useful symbol
length and an FDD frame structure with commonality with the TDD frame structure.
[0035J Secondly, the present invention is able to transmit/receive a signal using a
TDD frame structure that can coexist together with another TDD frame structure with a
different CP length.
[0036] It is to be understood that both the foregoing general description and the
following detailed description of the present invention are exemplary and explanatory and
are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0037] The accompanying drawings, which are included to provide a further
understanding of the invention and are incorporated in and constitute a part of this
application, illustrate embodiment(s) of the invention and together with the description
serve to explain the principle of the invention. In the drawings:
[0038] FIG. 1 is a diagram of a basic frame structure in IEEE 802.16m system;
[0039] FIG. 2 is a diagram for an example of TDD frame having a DL-to-UL ratio
set to 5:3;
[0040] FIG. 3 is a diagram for an example of a frame structure in FDD system;
[0041] FIG. 4 is a diagram for TDD and FDD frame structures with CP length
corresponding to 1/16 of a useful symbol length (Tu);
[0042] FIG. 5 is a diagram for an example of a symbol structure including a CP
(cyclic prefix);
[0043] FIGs. 6 to 10 are diagrams for examples of a TDD frame structure with a CP
length of 1/4 Tb, which can coexist together with another TDD frame structure with a
different CP length, according to a ratio of the number of DL subframe numbers to the
number of UL subframe numbers;
[0044] FIG. 11 is a diagram for an example of an FDD frame structure with a CP
length of 1/4 Tb;
[0045] FIGs. 12 to 16 are diagrams for examples of a TDD frame structure with a
CP length of 1/4 Tb, which can coexist together with a frame structure with a different CP
length, according to a ratio of the number of the DL subframes to the number of UL
subframes;
[0046] FIG. 17 is a diagram for an example of an FDD frame structure with a CP
length of 1/4 Tb;
[0047] FIG. 18 is a diagram for an example of a TDD frame structure with a CP
length of 1/4 Tb;
[0048] FIG. 19 is a diagram for an example of an FDD frame structure with a CP
length of 1/4 Tb;
[0049] FIG. 20 is a diagram for an example of a TDD frame structure with a CP
length of 1/4 Tb;
[0050] FIG. 21 is a diagram for an example of a TDD frame structure and a
corresponding FDD frame structure in case that a ratio of the number of DL subframes to
the number of UL subframe number is 4:2 in the TDD frame structure shown in FIG. 20;
[0051 ] FIG. 22 is a diagram for an example of a TDD frame structure with a CP
length of 1/4 Tb;
[0052] FIG. 23 is a diagram for an example of a TDD frame structure and a
corresponding FDD frame structure in case that a ratio of the number of DL subframes to
the number of UL subframes is 4:2 in the TDD frame structure shown in FIG. 20; and
[0053] FIG. 24 is a block diagram showing constitutional elements of a device 50
that may be either the MS or the BS.
DETAILED DESCRIPTION OF THE INVENTION
[0054] Reference will now be made in detail to the preferred embodiments of the
present invention, examples of which are illustrated in the accompanying drawings. In the
following detailed description of the invention includes details to help the full
understanding of the present invention. Yet, it is apparent to those skilled in the art that the
present invention can be implemented without these details. For instance, although the
following descriptions are made centering on predetermined terminologies, they need not to
be limited to the terminologies. If the following descriptions are made using random
terminologies, the same meanings can be provided. Wherever possible, the same reference
numbers will be used throughout the drawings to refer to the same or like parts.
[0055] Throughout this disclosure, if a prescribed part 'includes' a prescribed
element, it means that another element can be further included instead of eliminating other
elements as long as absence of special objection.
[0056] The following descriptions are applicable to various communication systems,
which are capable of providing various communication services of audio data, packet data,
and the like. The technology of the communication system is usable in DL (downlink) or
UL (uplink). In this case, 'base station' can be replaced by such a terminology as a fixed
station, a Node B, an eNode B (eNB), an access point, an ABS and the like. And, 'mobile
station (MS)' can be replaced by such a terminology as a user equipment (UE), a subscriber
station (SS), a mobile subscriber station (MSS), an AMS, a mobile terminal and the like.
[0057] A transmitting end means a node for transmitting data or audio service, and
a receiving end means a node for receiving the data or audio service. Therefore, a mobile
station becomes a transmitting end and a base station becomes a transmitting end, in uplink.
Likewise, a mobile station becomes a receiving end and a base station becomes a receiving
end, in downlink.
[0058] Meanwhile, a mobile station of the present invention can include a PDA
(personal digital assistant), a cellular phone, a PCS (personal communication service) phone,
a GSM (global system for mobile) phone, a WCDMA (wideband CM DA) phone, an MBS
(mobile broadband system) phone or the like.
[0059] Embodiments of the present invention are supportable by standard
documents disclosed in at least one of wireless access systems including IEEE 802 system,
3GPP system, 3GPP LTE system and 3GPP2 system. In particular, the steps or parts, which
are not explained to clearly reveal the technical idea of the present invention, in the
embodiments of the present invention can be supported by the above documents. Moreover,
all terminologies disclosed in this document can be supported by at least one of P802.16-
2004, P802.16e-2005, P802.16Rev2 and P802.16m documents which are the standards of
IEEE 802.16 system.
[0060] In the following description, a preferred embodiment of the present
invention is explained in detail with reference to the accompanying drawings. Detailed
description disclosed together with the accompanying drawings is intended to explain not a
unique embodiment of the present invention but an exemplary embodiment of the present
invention. In the following description, specific terminologies used for embodiments of the
present invention are provided to help the understanding of the present invention. And, the
use of the specific terminology can be modified into another form within the scope of the
technical idea of the present invention.
[0061] Basic principles of OFDM (orthogonal frequency division multiplexing),
which are multi-carrier modulation scheme in wireless communication systems, are
described as follows.
[0062] First of all, in OFDM system, a high-rate data stream is divided into a
number of slow-rate data streams. This is to simultaneously transmit the data streams using
a plurality of carriers. Each of a plurality of the carriers is called a subcarrier. Since
orthogonality exists among a plurality of carriers in OFDM system, even frequency
components of carriers are mutually overlapped with each other, they can be detected by a
receiving end. A high-rate data stream is converted to a plurality of slow-rate data streams
by a serial to parallel converter. A plurality of the data streams converted in parallel are
multiplied by subcarriers, respectively and are then added together. The added data streams
are transmitted to a receiving end.
[0063] A plurality of the parallel data streams generated by the serial to parallel
converter can be carried on a plurality of subcarriers by IDFT (inverse discrete Fourier
transform). In this case, it is able to efficiently implement the IDFT using IFFT (inverse fast
Fourier transform). As a symbol duration of a slow-rate subcarrier increases, relative time-
domain signal dispersion generated by multi-path delay spreading is reduced.
[0064] In wireless communication using this OFDM system, it is able to insert a
guard interval longer than a delay spreading of channel between symbols in order to reduce
inter-symbol interference. In particular, while each symbol is being transmitted on a multi-
path channel, a guard interval longer than a maximum delay spread of channel is inserted
between contiguous symbols. In doing so, in order to prevent inter-subcarrier orthogonality
breakage, a signal in a last interval (i.e., a guard interval) of a useful symbol interval is
copied and then inserted in a fore part of a symbol. This is called a cyclic prefix (hereinafter
abbreviated CP).
[0065] FIG. 5 is a diagram for an example of a symbol structure including a CP
(cyclic prefix).
[0066] Referring to FIG. 5, a symbol duration Ts becomes a sum of a useful symbol
interval Tb for carrying data actually and a guard interval Tg. A receiving end removes the
guard interval and then performs demodulation by taking data for the useful symbol interval.
A transmitting end and a receiving end may be synchronized with each other using a cyclic
prefix code and the inter-data symbol orthogonality is maintained. In this case, a symbol of
the present invention may be an OFDMA symbol.
[0067] In the following description, explained are frame structures (TDD frame and
FDD frame) in 802.16m system with a CP length (hereinafter named a CP length of 1/4 Tb)
corresponding to 1/4 of a useful symbol length on a channel bandwidth of 8.75 MHz. And,
a TDD frame structure, which can mutually coexist with a TDD frame structure with a CP
length of 1/8 or 1/16 Tb for the same channel bandwidth of 8.75 MHz, will be explained.
Moreover, an FDD frame structure with many commonalities with a TDD frame structure
proposed by the present invention is explained as well.
[0068] In IEEE 802.16m system, subframes of 4 kinds of types exist. Theses types
can be defined as follows. First of all, a first type subframe is a subframe including 6
OFDMA symbols. A second type subframe is a subframe including 7 OFDMA symbols. A
third type subframe is a subframe including 5 OFDMA symbols. And, a fourth type
subframe is a subframe including 9 OFDMA symbols. In this case, the fourth type subframe
may be used for a frame structure on 8.75MFIz channel bandwidth.
[0069] As shown in Table 1, OFDMA parametersin case of using a CP length of
1/4 Tb on 8.75MFIz channel bandwidth may be defined, as the same method for a
conventional method for the case of a CP length of 1/8 or 1/16 Tb. In case of with the CP
length of 1/4 Tb, a symbol duration of OFDM is 128 us and relative TTG (transmit
transition gap) and RTG (receive transition gap) are 61.6 us and 74.4 us, respectively. In
consideration of the defined OFDMA parameters, in case of using a CP length of 1/4 Tb,
the number of symbols existing within one frame is 39. A frame structure with a CP length
of 1/4 Tb using the first to third type subframes according to the number of symbols used to
define a subframe in a previous frame structure may be constructed. And, the number of
symbols within the frame with the CP length of 1/4 Tb is 39.
[0070] In case that a frame is constructed with 7 subframes in the same manner of
the previous CP length of 1/8 or 1/16 Tb, one OFDMA symbol may be allocated to TTG
and RTG interval in a TDD frame structure. And, the remaining 38 OFDMA symbols may
be allocated to downlink and uplink. In this case, a TDD frame may include 3 first type
subframes and 4 third type subframes.
[0071] FIGs. 6 to 10 are diagrams for examples of a TDD frame structure with a CP
length of 1/4 Tb, which can coexist together with another TDD frame structure with a
different CP length, according to a ratio of the number of DL subframes to the number of
UL subframes, respectively .
[0072] Referring to FIGs. 6 to 10, a ratio of the number of DL subframesto the
number of UL subframes may be set to (2:5), (3:4), (4:3), (5:2) or (6:1). If the ratios of the
number of DL subframcs to the number of UL subframes is set to (2:5), (3:4), (4:3), (5:2) or
(6:1), respectively, when a communication is performed using a frame structure with a CP
length of 1/4 Tb on 8.75MHz channel bandwidth according to the present invention,
interference with a previous frame with a CP length of 1/8 or 1/16 Tb is not generated at a
DL/UL switching point. Therefore, frame structures with different CP lengths can coexist
mutually.
[0073] Since two of 3 first type subframes locate not to be affected by the ratio of
the DL subframe number to the UL subframe number, respectively. They are preferably
located at a first DL subframe and a last UL subframe in one TDD frame, respectively. Yet,
this is just exemplary. The first type subframes are not always located in this manner. A first
DL/UL subframe in TDD frame is configured with a first type subframe including 6
symbols so that the first uplink/downlink subframe start with the first type subframe.
Besides, the remaining first type subframe may be located within a DL or UL subframe in
consideration of the ratio of the DL subframe number to the UL subframe number, the
location of the remaining first type subframe is non-limited.
[0074] Generally, a last DL subframe located in an interval for the switching to UL
from DL includes a subframe constructed with 6 symbols by including an idle interval.
However, in order to generate a time difference (or delay) necessary for TTG interval, the
last DL subframe may be configured with 5 symbols by having one symbol set to an idle
interval. This configuration is always applicable irrespective of the ratio of the DL subframe
number to the UL subframe number. In TDD frame, one symbol may be allocated to an idle
interval of TTG/RTG.
[0075] In case that 2 first type subframes are located in a DL region, one of the 2
first type subframes may be located at a first subframe of a DL frame to use a super frame
header (SFH) constructed with 6 symbols. If the other first type subframe is located at a last
DL sub frame, the last DL subframe is a subframe constructed with 7 symbols by including
an idle interval or the last DL, subframe may be constructed with 6 symbols by allocating
one symbol to an idle interval to generate a time difference necessary for TTG interval. This
configuration is applicable to a case that a ratio of the number of DL subframes to the
number of UL subframes is set to (4:3), (5:2) or (6:1). In this case, for the purpose of
coexistence without interference with a previous frame structure with a different CP length,
2 first type subframes may be located in the DL region (interval). This TDD frame structure
is shown in FIGs. 8 to 10.
[0076] In case that a first type subframe is located at a first subframe of DL
subframes, another first type subframe except the above mentioned subframe may be
randomly located in the DL region.
[0077J In the examples of the above-mentioned frame configurations, if a first type
subframe in a DL interval is located at a first DL subframe of TDD frame and a first type
subframe in a UL interval is a last UL subframe of the TDD frame, or the first type
subframes are located at a first subframe of a DL interval and a first subframe of a UL
interval, respectively, it is able to solve the above-mentioned interference problem that may
be generated from a switching interval from DL to UL.
[0078] If the first type subframes are located at the first DL subframe and the last
UL subframe of the TDD frame or the first type subframes is located at the first DL
subframe and the first UL subframe, as shown in FIGs. 6 to 10, it is just one example for
coexistence with a previous frame structure with a different CP length. In particular, a
subframe configured with 6 symbols may be located at a random subframe in each DL or
UL region. Moreover, even if a first type subframe and a second type subframe are located
at a first DL frame and a second DL frame in a previous frame structure with a CP length of
1/16 Tb, respectively, as shown in one of FIGs. 6 to 10, the TDD frame structure of the
present invention proposed in FIGs. 6 to 10 can mutually coexist with a previous frame
structure with a CP length of 1/8 or 1/16 Tb.
[0079] FIG. 11 is a diagram for an example of an FDD frame structure with a CP
length of I /4 Tb.
[0080] FDD frame structure shown in FIG. 11 is a frame structure corresponding to
the TDD frame structure shown in one of FIGs. 6 to 10 and is able to have commonality
with the TDD frame structure. If this frame structure is designed to have commonality with
a TDD frame structure, it is advantageous in reusing the design of channel for essential
control information or additional control information in physical layer design taken into
consideration in designing a system. Therefore, an FDD frame structure is preferably
configured by succeeding to a TDD frame structure. And, 39 symbols may be allocated to
an FDD frame.
[0081] A basic structure of the FDD frame may include 7 subframes in the same
manner of the TDD frame structures shown in FIGs. 6 to 10. And, 39 symbols may be
allocated to this structure. First type subframes are located to first and last subframes of the
FDD frame to maintain commonality. If first type subframes are located at first subframes
of DL and UL regions in the TDD frame structure, respectively, it is able to maintain the
commonality in allocating 6 symbols thereto in the same manner of a previous structure. In
this case, the first type subframe arranged in each region additionally may be located at a
random subframe in the corresponding region without limitation put on its location. In
particular, if a first type subframe is located at a second subframe in FIG. 11, it is just one
example for an FDD frame structure. Thus, limitation is not put on the location of the first
type subframe in the DL/UL region.
[0082] Since the FDD frame structure does not need TTG/RTG of the TDD frame
structure, it is able to further utilize one symbol. Therefore, it is able to consider that a
second type subframe is configured by adding one remaining symbol to a first, a first type
subframe is configured by adding the one remaining symbol to third type subframe. A
iocation of a subframe, to which one symbol can be additionally allocated, may include 3,u'
4th' or 5th subframe in FDD frame in Case 1/2/3/4 shown in FIG. 11. This considers H-FDD
frame structure. In case of considering the H-FDD frame structure, an additional idle
interval is required between groups. For this, it is able to configure such an additional
interval using a first or second type subframe. Yet, this is a considered location for example.
Limitation is not put on a location of the first or second type subframe to which one symbol
is added.
[0083] Alternatively, there is a method of allocating one remaining symbol
individually. Referring to Case 5 shown in FIG. 11, one additional symbol may be allocated
to a first subframe in an FDD frame. Since symbol-unit essential control informations such
as a preamble or a frame control header (FCM) are carried on a head part of a frame, a first
type subframe may be used for data transmission using one symbol after the control
information has been transmitted. Alternatively, referring to Case 8 shown in FIG. 11, one
symbol is allocated to a last subframe of the FDD frame and is used to transmitt additional
information like sounding.
[0084] Moreover, in case of considering H-FDD frame structure, one symbol may
be preferably located in front or rear of a 4n subframe. This is one example for a preferable
location only. And, a location of one added symbol is non-limited by the present invention.
[0085] As mentioned in the foregoing description, in case that one frame is
configured with 7 subframes, 2 first type subframes may be located at 1st and last subframes
in the corresponding frame. And, it is able to consider that one remaining first type
subframe is located at a 2nd subframe or a random subframe in a DL interval.
[0086] FIGs. 12 to 16 arc diagrams for examples of a TDD frame structure with a
CP length of 1/4 Tb, which can coexist together with a frame structure with a different CP
length, according to a ratio of the number of DL subframes to the number of UL subframes.
[0087] Referring to FIGs. 12 to 16, a ratio of the number of DL subframes to the
number of UL subframes may be set to one of (2:5), (2:4), (3:4), (3:3), (4:3), (5:2), (4:2).
(6:1) and (5:1). If the ratio of the number of DL subframes to the number of UL subframes
in FIG. 12 is (2:5) or (2:4), a ratio of the total number of symbols allocated to DL subframes
to the total number of symbols allocated to UL subframes is (12:26). If the ratio of the
number of DL subframes to the number of UL subframes in FIG. 13 is (3:4) or (3:3), a ratio
of the total number of symbols allocated to DL subframes to the total number of symbols
allocated to UL subframes is (17:21). If the ratio of the DL subframe number to the UL
subframe number in FIG. 14 is (4:3) or (3:3), a ratio of the total number of corresponding
symbols ailocated to DL subframes to the total number of corresponding symbols allocated
to UL subframes is (22:16) or (21:17). If the ratio of the DL subframe number to the UL
subframe number in FIG. 15 is (5:2) or (4:2), a ratio of the total number of corresponding
symbols allocated to DL subframes to the total number of corresponding symbols allocated
to UL subframes is (27:11) or (26:12). If the ratio of the DL subframe number to the UL
subframe number in FIG. 16 is (6:1), a ratio of the total number of symbols allocated to DL
subframes to the total number of symbols allocated to UL subframes is (32:6). If the ratio of
the DL subframe number to the UL subframe number in FIG. 16 is (5:1), a ratio of the total
number of symbols allocated to DL subframes to the total number of symbols allocated to
UL subframes is (31:7) or (32:6).
[0088] In order to coexist without interference with a frame structure with a
previously defined CP length of 1/16 Tb, it is necessary for DL/UL switching points not to
be overlapped with each other. For this, it is able to consider that a frame structure with a
CP length of 1/4 Tb is configured with 6 subframes. In TDD frame, one symbol may be
allocated for TTG/RTG interval. And, it is able to configure a TDD frame constructed with
6 subframes using 38 remaining symbols like the two following cases.
[0089] In the first case, a TDD frame may be constructed with 4 second type
subframes and 2 third type subframes. In the second case, a TDD frame may be constructed
with 4 first type subframes and 2 second type subframes.
[0090J In consideration of an idle interval, a first or second type subframe may be
located at a last DL frame that is a switching interval from DL to UL in a TDD frame
structure. If the second type subframe is located at the last DL subframe, a new type
subframe constructed with 8 symbols by including the idle interval is generated. This
deviates from a scope of a previously defined subframe. Therefore, the new type subframe
needs to be defined.
[0091] In case that the second type subframe is allocated to the last DL subframe
located in the interval for switching to UL from DL in consideration of the idle interval, one
symbol may be set to the idle interval for a delay necessary for a TTG interval. Hence, the
first type subframe constructed with 6 symbols may be located at the last DL subframe. In
this case, first type subframes may be located at first and last subframes of a frame in a DL
region. This configuration is applicable irrespective of a ratio of the number of DL
subframes to the number of UL subframes.
[0092] In order to coexist without interference with a previously defined frame
structure with a CP length of 1/16 Tb, if one frame is configured using 6 subframes like the
first case, a third type subframe may be located at a last DL subframe in consideration of a
switching interval from DL to UL irrespective of the ratio of the DL subframe number to
the UL subframe number. Moreover, referring to FIG. 14, if the ratio of the DL subframe
number to the UL subframe number is (3:3), a new type subframe constructed with 8
symbols may be located at a last DL subframe.
[00931 In the second case for constructing a frame with first and second type
subframes, if the first type subframes are located at first subframes in DL and UL regions,
respectively, the first or second type subframe may be located at a last DL subframe that is a
switching interval from DL to UL. In this case, in consideration of 1 symbol allocated for an
idle time of the switching interval, a subframe constructed with 7 or 8 symbols may be
located at a last DL subframe. In this case, in order to coexist without interference with a
previously defined frame structure with a CP length of 1/16 Tb, 2 second type subframes
constructing a TDD frame may be located in the DL and UL regions, respectively.
Corresponding examples are shown in FIG. 12, FIG. 15 and FIG. 16. In this case, the
locations of the first and second type subframes are just exemplary. And, the locations of
the subframes of the above types are non-limited in the DL and UL regions.
[0094] FIGs. 12 to 16 show a frame structure to coexist without interference with a
previously defined frame structure with a CP length of 1/16 Tb using 7 subframes. In FIGs.
12 to 16, if one frame is constructed with 6 subframes, second type subframes are arranged
at first and last subframes in a frame or DL and UL intervals, respectively. This is just
exemplary only. A subframe constructed with 7symbols may be located at a random
subframe in each DL/UL region.
[0095] FIG. 17 is a diagram for an example of an FDD frame structure with a CP
length of 1/4 Tb.
[0096] First of all, an FDD frame structure shown in FIG. 17 is a frame structure
corresponding to the TDD frame structure shown in FIGs. 12 to 16. A frame structure for
FDD is preferably configured by succeeding to a TDD structure. By applying the above-
described FDD frame structure per Case, it is able to appropriately configure an FDD frame.
Therefore, like the TDD frame structures shown in FIGs. 12 to 16, one frame consists of 7
subframes in this frame structure. And, an FDD structure for a case that a first type
subframe is iocated at a second subframe of a frame can consider a frame structure like one
of FDD-Cases 4 to 9 shown in FIG. 11.
[0097] In case that an FDD frame is constructed with 6 subframes, one frame
consists of 6 subframes like a previous TDD frame structure, as shown in FIGs. 12 to 16.
And, second type subframes are located at first and last subframes and second and fifth
subframes of the frame, respectively to maintain a symmetric structure.
[0098] Meanwhile, 39 symbols may be allocated to the FDD frame shown in FIG.
17. Since TTG/RTG is not required for the FDD frame structure unlike the TDD frame
structure, one symbol may be used in addition. Therefore, it is able to consider configuring
a first type subframe in a manner of adding a remaining symbol to a third type subframe.
The subframe including added one symbol thereto may be located at 3rd or 4th subframe in
the frame of Cases 1 to 4 shown in FIG. 17.
[0099] Yet, this considers FI-FDD frame structure. In case of considering H-FDD
structure, an inter-group idle interval is additionally necessary. For this, the additional inter-
group idle interval is configured using a first or second type subframe. Moreover, a location
of the first or second type subframe having one symbol added thereto is non-limited by the
present invention.
[00100] As another method of allocating one additional symbol, there is an
individual allocation method. A location of this symbol is shown in Cases 1 to 4 of FIG. 17
described in consideration of H-FDD. In this case, this symbol is preferably located
between 3rd and 4th subframes. This location is a preferable location only. The location of
the added symbol is non-limited by the present invention. Therefore, as mentioned in the
foregoing description of the FDD frame structure, one symbol may be allocated to a first or
last subframe in a frame individually.
[00101| FIG. 18 is a diagram for an example of a TDD frame structure with a CP
length of 1/4 Tb.
[00102] Referring to FIG. 18, in case that one TDD frame consists of 6 subframes, it
is able to construct a frame by allocating first type subframes, each of which includes 6
symbols, more. In this case, one TDD frame may consist of 4 first type subframes and 2
second type subframes. Since it is preferable that the 2 second type subframes are located at
positions not to be affected by a ratio of the number of DL subframes to the number of UL
subframes, the 2 second type subframes may be located at a first DL subframe and a last UL
subframe in one frame, respectively. Thus, the second type subframes are located at the first
DL subframe and the last UL subframe, respectively. This is just exemplary and the location
of the second type subframe is non-limited.
[00103] When the number of DL subframes is at least 2, in case of considering a
ratio of the number of DL subframes to the number of UL subframes, the second type
subframe may be located at a 2" subframe in a frame. As mentioned in the foregoing
description, it is able to configure a frame in a manner of arranging first type subframes at
1st subframes in DL and UL regions, respectively. Thus, as the first type subframe having 6
symbols is located at the 1st subframe in the frame, it is able to successively use the previous
super frame header structure defined as 6 symbols without amending a subframe structure.
[00104] Although the last DL subframe located at the switching interval from DL to
UL is the subframe constructed with 7 symbols by including the idle interval, it is generally
able to construct a subframe with 6 symbols by allocating one symbol to an idle interval to
generate a time difference necessary for TTG interval. This configuration is applicable
irrespective of the ratio of the DL subframe number to the UL subframe number.
[00105| In FIG. 18, shown arc a frame structure, in which second type subframes are
located at first and last subframes in a frame, respectively and a frame structure, in which
first type subframes are iocated at first subframes of DL and UL regions, respectively. The
frame structure shown in FIG. 18 is just exemplary. And, locations of the first and second
type subframes for configuring one frame are non-limited.
[00106] FIG. 19 is a diagram for an example of an FDD frame structure with a CP
length of 1/4 Tb.
[00107] First of all, an FDD frame structure shown in FIG. 19 corresponds to a
frame structure corresponding to the TDD frame structure shown in FIG. 18. Preferably, the
FDD frame structure is configured by succeeding to the TDD frame structure. By applying
the FDD frame structure per Case proposed in the foregoing description, a proper FDD
frame structure can be taken into consideration. A second type subframe, as shown in FIG.
18, may be located at a first, second or last subframe in a frame. And, first type subframes
may be arranged at first subframes of DL and UL regions, respectively.
[00108] In this case, as the FDD frame structure does not need a TTG/RTG interval
unlike the TDD frame structure, one symbol may be additionally utilized. Therefore, it is
able to consider configuring a second type subframe by adding a remaining symbol to a first
type subframe. The subframe having the added symbol located thereat can be located at a
3r or 4* subframe in a frame, as shown in Case 1 or Case 2 of FIG. 19. This considers H-
FDD frame structure. In case of considering H-FDD frame structure, an additional idle
interval between groups is necessary. For this, it is able to additionally configure a
necessary interval using a second type subframe. Yet, this is just am example of considered
location. And, a location of a second type subframe, to which one symbols is added, is non-
limited by the present invention.
[00109] As another method of allocating one additional symbol, there is a method of
arranging one remaining symbol individually. If a symbol is added in front of a Ist subframe
in a frame, as shown in Case 3 of FIG. 19, it is to transmit such control information carried
on a head part of a frame as essential control informations of symbol unit such as a
preamble or a frame control header (SFH).
[00110] Besides, unlike the above description, it is able to use one symbol to carry
such additional information as sounding in a manner of allocating a symbol in rear of a last
subframe in a frame, as shown in Case 5. Preferably, in consideration of the H-FDD frame
structure, one symbol is located between a 3rd subframe and a 4th subframe. This is an
example of a preferred location only. And, a location of an added symbol is non-limited by
the present invention.
[00111] Moreover, as mentioned in the foregoing description, a second type
subframe located at a 1st subframe in a frame may be located at a 2" subframe in the frame.
And, a first type subframe may be located at the 1st subframe in the frame. In this case, the
second type subframe located at the 1st subframe in the frame can be represented as a
structure that the second type subframe is located at a 2n subframe in an FDD frame
structure, as shown in FIG. 19. In a manner that a first type subframe including 6 symbols is
located at a 1st subframe in a frame, it is able to use a previously defined super frame header
structure constructed with 6 symbols without modification.
[00112] Thus, a signal is transmitted/received using a TDD frame structure for 8.75
MHz channel bandwidth with a CP length of 1/4 Tb according to the present invention and
an FDD structure having commonality with the TDD frame structure. Therefore, mutual
coexistence with a previously defined frame with a different CP length is possible.
[00113] In the following description, TDD frame structure for 8.75 MHz channel
bandwidth with a CP length of 1/4 Tb in IFZEE 802.16m system and an FDD frame structure
having commonality with the TDD frame structure are explained.
[00114] A TDD frame structure for 8.75 MHz channel bandwidth with a CP length
of 1/4 Tb according to the present invention and an FDD frame structure have commonality
with a previously defined frame with a different CP length. In order to coexist together with
the previously defined frame with a different CP length, this frame structure does not cause
interference in a manner that switching points from DL to UL are not overlapped with each
other in TDD frame. In case of using a CP length of 1/4 Tb on 8.75 MHz, as shown in Table
1, OFDMA parameters can be defined by the method for a previous case of CP length of 1/8
Tb or 1/16 Tb. If a CP length is set to 1/4 Tb, a symbol duration of OFDM is 128 us and the
number of OFDMA symbols existing in one frame is 39.
[00115] It is able to construct a frame structure with a CP length of 1/4 Tb using first
to third type subframes according to the number of symbols used to define a subframe in a
previous frame structure. In a TDD frame structure, one symbol may be allocated as a
TTG/RTG interval. In case that DL and UL regions are allocated with 38 remaining
symbols, relative TTG and RTG are set to 61.6 u,s and 74.4 us, respectively. This is a value
smaller than that of TTG/RTG in a previous frame structure with a CP length of 1/8 or 1/16
Tb shown in Table 1. Therefore, if a switching to UL from DL is performed, a problem may
be caused.
[00116] Yet, according to the present invention, in order to generate an interval
similar to TTG/RTG of a previously defined frame with a different CP length in a frame, it
is able to construct a frame with 37 symbols remaining after 2 symbols have been allocated
as TTG and RTG intervals in a TDD frame structure.
[00117] FIG. 20 is a diagram for an example of a TDD frame structure with a CP
length of 1/4 Tb.
[00118] Referring to FIG. 20, a TDD frame may be constructed with 6 subframes in
order to use a first type subframe of a previous subframe type, which includes 6 symbols, as
many as possible. And. one frame consists of 5 first type subframes and one second type
subframe. In particular, when a frame is constructed by allocating 38 symbols, a second
type subframe may be changed into a first type subframe by allocating one symbol to one of
the 2 second type subframes for TTG/RTG. As a corresponding result, it is able to configure
a frame structure, of which number of second type subframes is decremented by 1 smaller
than that of a previous case of allocating one symbol. In particular, in a TDD frame
structure, one symbol may be allocated as an idle interval for TTG/RTG.
[00119] In FIG. 20, if a ratio of the number of DL subframes to the number of UL
subframes is (5:1), (4:2), (3:3), or(2:4), a ratio of the total number of symbols allocated to
corresponding DL subframes to the total number of symbols allocated to UL subframes can
become (31:6), (25:12), (19:18), or( 13:24), respectively.
[00120] One second type subframe existing in a TDD frame may be located in DL or
UL region. In this case, since a previously defined first type subframe is preferably located
at a first subframe of a frame to transmit a preamble and a super frame header (SFH) in case
of DL, second type subframes are preferably located in a manner of starting with a second
subframe in the frame. Therefore, as the first type subframe having 6 symbols is located at
the first subframe in the frame, it is able to use a super frame header structure previously
defined with 6 symbols without modifying a subframe structure by succeeding to the
corresponding super frame header structure. This frame configuration is just exemplary.
And, the second type subframe can be located at a random subframe in the frame.
[00121] Although a last DL subframc located in a switching interval to UL from DL
is a subframe constructed with 7 symbols by including an idle interval, it can be constructed
with 6 symbols by allocating one symbol to an idle interval to generate a time difference
necessary as a TTG interval in general.
[00122] Yet, in case that a ratio of the number of DL subframes to the number of UL
subframes is (2:4). a second type subframe may be located at the last DL subframe. In this
case, the last subframe is constructed with 7 symbols. In configurations except this case, a
last frame can be constructed with 6 symbols irrespective of the ratio of the DL subframe
number to the UL subframe number. A frame can be configured in a manner of further
allocating one symbol of another second type subframe for TTG to generate a first type
subframe. FIG. 20 shows a frame structure in which a second type subframe is located at a
second subframe in a frame.
[00123] FIG. 21 is a diagram for an example of a TDD frame structure and a
corresponding FDD frame structure in case that a ratio of the number of DL subframes to
the number of UL subframes is 4:2 in the TDD frame structure shown in FIG. 20.
[00124] Referring to FIG. 21, since it is unnecessary to set an additional idle interval
for TTG/RTG in an FDD frame structure, it is able to configure a frame using 39 OFDMA
symbols. In case that an FDD frame is constructed with 6 subframes like a TDD frame, it
can be constructed with 3 first type subframes and 3 second type subframes. In this case, in
order to transmit a super frame header constructed with 6 symbols, a first type subframe is
preferably located at a first subframe of a frame.
[00125] It is able to transmit such additional information as sounding in a manner of
allocating one additional symbol in rear of a 3rd or 4th subframe independently in
consideration of an H-FDD frame structure or a mid-amble within the frame or arranging
one symbol in rear of a last subframe of the frame. Thus, it is able to transmit a signal
without modifying a previous subframe structure for data transmission.
[00126] FIG. 22 is a diagram for an example of a TDD frame structure with a CP
length of 1/4 Tb.
[00127] First of all, a TDD frame structure shown in FIG. 22 is configured in a
manner that the second type subframe located in the DL interval of the former TDD frame
structure shown in FIG. 20 is located in a UL. In this case, a location of the second type
subframe in the UL is non-limited. In this case shown in FIG. 22, 2 symbols are allocated as
TTG/RTG interval for the switching from DL to UL like the case shown in FIG. 20. In this
case, although a last DL subframe is a subframe constructed with 7 symbols, it can be
constructed with 6 symbols by allocating one symbol to an idle interval to generate a time
difference generally necessary for a TTG interval. This configuration is applicable
irrespective of a ratio of the number of DL subframes to the number of UL subframes.
Another frame can be configured in a manner of constructing a first type subframe
including 6 symbols by allocating one symbol of another second type subframe existing in a
frame to an idle interval. Therefore, all DL subframes can include first type subframes. And,
a second type subframe is arranged at a first UL subframe to use for discrimination between
DL and UL.
[00128] In the TDD frame structure shown in FIG. 22, if a ratio of the number of DL
subframes to the number of UL subframes is (5:1), (4:2), (3:3), or(2:4), a ratio of the total
number of symbols allocated to corresponding DL subframes to the total number of
symbols allocated to corresponding UL subframes can be set to (30:7), (24:13), (18:19), or
(12:25).
[00129] FIG. 23 is a diagram for an example of" a TDD frame structure and a
corresponding FDD frame structure in case that a ratio of the number of DL subframes to
the number of UL subframes is 4:2 in the TDD frame structure shown in FIG. 20.
[00130] Referring to FIG. 23, a TDD frame structure for the specific ratio of TDD
shown in FIG. 22 and an FDD frame structure are illustrated. In the TDD frame structure
shown in FIG. 23, a second type subframe is allowed to exist in an UL region only. In
particular, the second type subframe may be located at a 1st one of UL subframes. In this
case, it is able to discriminate UL and DL from each other using the second type subframe.
Moreover, no limitation is put on a location of the second type subframe in UL.
[00131] In the above frame configurations described with reference to FIGs. 20 to 23,
for a case that a ratio of the number of DL subframes to the number of UL subframes is
(6:0), it is not necessary for a TDD frame to separately set an idle interval for DL/UL
switching like the FDD frame. In this case, the TDD frame structure has the same
configuration of the FDD frame structure. And, a first type subframe may be located at a 1st
subframe in a frame to transmit a super frame header constructed with 6 symbols. If so, it is
able to use a super frame structure, which is defined using 6 symbols, and a control channel
structure in succession without designing a new subframe structure.
[00132] Accordingly, if a frame structure with a CP length of 1/4 Tb according to the
present invention is designed, it is able to solve the problem that a previous TTG/RTG
interval may become smaller than a TTG/RTG interval set in a frame structure with a
different CP length (e.g., a CP length of 1/8 Tb, a CP length of 1/16 Tb, etc.).
[00133] FIG. 24 is a block diagram showing constitutional elements of a device 50,
that may be either the MS or the BS, and that can perform the methods of FIGs 6 to 23.
Device 50 includes a processor 51, a memory 52, a radio frequency (RF) unit 53, a display
unit 54, and a user interface unit 55. Layers of the radio interface protocol are implemented
in the processor 51. The processor 5 I provides the control plane and the user plane. The
function of each layer can be implemented in the processor 51. The processor 5 1 may also
include a contention resolution timer. The memory 52 is coupled to the processor 51 and
stores an operating system, applications, and general files. If device 50 is a MS, the display
unit 54 displays a variety of information and may use a well-known element such as a liquid
crystal display (LCD), an organic light emitting diode (01.ED), etc. The user interface unit
55 can be configured with a combination of well-known user interfaces such as a keypad, a
touch screen, etc. The RF unit 53 is coupled to the processor 51 and transmits and/or
receives radio signals. The RF unit 53 may include transmitting module, receiving module,
transceiving module.
[00134] Layers of a radio interface protocol between the UE and the network can be
classified into a first layer (LI), a second layer (L2), and a third layer (L3) based on the
lower three iayers of the open system interconnection (OS1) model that is weil-known in the
communication system. A physical layer, or simply a PHY layer, belongs to the first layer
and provides an information transfer service through a physical channel. A radio resource
control (RRC) layer belongs to the third layer and serves to control radio resources between
the UE and the network. The UE and the network exchange RRC messages via the RRC
layer.
(00135) The aforementioned embodiments are achieved by combination of structural
elements and features of the present invention in a predetermined type. Each of the
structural elements or features should be considered selectively unless specified separately.
Each of the structural elements or features may be carried out without being combined with
other structural elements or features. Also, some structural elements and/or features may be
combined with one another to constitute the embodiments of the present invention. The
order of operations described in the embodiments of the present invention may be changed.
Some structural elements or features of one embodiment may be included in another
embodiment, or may be replaced with corresponding structural elements or features of
another embodiment. Moreover, it will be apparent that some claims referring to specific
claims may be combined with another claims referring to the other claims other than the
specific claims to constitute the embodiment or add new claims by means of amendment
after the application is filed.
[00136] Embodiments of the present invention can be implemented using various
means. For instance, embodiments of the present invention can be implemented using
hardware, firmware, software and/or any combinations thereof. In the implementation by
hardware, one embodiment of the present invention can be implemented by at least one
selected from the group consisting of ASICs (application specific integrated circuits), DSPs
(digital signal processors), DSPDs (digital signal processing devices), PLDs (programmable
logic devices), FPGAs (field programmable gate arrays), processor, controller,
microcontroller, microprocessor and the like.
[00137] In case of the implementation by firmware or software, one embodiment of
the present invention can be implemented by modules, procedures, and/or functions for
performing the above-explained functions or operations. Software code is stored in a
memory unit and is then drivable by a processor. The memory unit is provided within or
outside the processor to exchange data with the processor through the various means known
to the public.
[00138] It will be apparent to those skilled in the art that various modifications and
variations can be made in the present invention without departing from the spirit or scope of
the inventions. Thus, it is intended that the present invention covers the modifications and
variations of this invention provided they come within the scope of the appended claims and
their equivalents.
WHAT IS CLAIMED IS:
1. A method for transceiving a signal using a frame structure in a wireless
communication system, the method comprising:
transceiving a signal through a frame according to the frame structure,
wherein the frame comprises 6 subframes. and the 6 subframes comprise at least one
of a first type subframc including 6 OFDMA (orthogonal frequency division multiple
access) symbols or a second type subframe including 7 OFDMA symbols.
2. The method of claim 1, wherein the frame is a TDD (time division duplex)
frame or an FDD (frequency division duplex) frame.
3. The method of claim 2, wherein the TDD frame includes a downlink interval
and an uplink interval subsequent to the downlink interval, and wherein the first type
subframe is located at a first downlink subframe of the downlink interval and a first uplink
subframe of the uplink interval.
4. The method of claim 3, wherein the second type subframe is located at a
second downlink subframe of the downlink interval and a second uplink subframe of the
uplink interval.
5. The method of claim 4, wherein a TTG (transmit transition gap) is located
between the downlink interval and the uplink interval in the TDD frame, and wherein an
RTG (receive transition gap) is located next to a last subframe of the uplink interval in the
TDD frame.
6. The method of claim 5, wherein the TDD frame includes 4 first type
subframes and 2 second type subframes.
7. The method of claim 6, wherein a ratio of a number of downlink subframes
to a number of uplink subframes number in the TDD frame is set to one of 5:1, 4:2, 3:3, and
2:4.
8. The method of claim 2, wherein the second type subframe in the FDD frame
is located in the same order of a last downlink subframe located in the TDD frame.
9. The method of claim 8, wherein the second type subframe is located at a
fourth subframe in the FDD frame.
10. The method of claim 9, wherein the FDD frame includes 3 first type
subframes and 3 second type subframes.
11. The method of claim 10, wherein an idle time is located next to a last
subframe in the FDD frame.
12. The method of claim 1, wherein the frame comprises a CP (cyclic prefix), a
length of the CP is set to 1/4 of a useful symbol length.
13. The method of claim 1, wherein a channel bandwidth of the frame is set to
8.75 MHz.
14. An apparatus for transceiving a signal using a frame structure in a wireless
communication system, the apparatus comprising:
transceiving module for transceiving a signal through a frame according to the frame
structure,
wherein the frame comprises 6 subframes, and the 6 subframes comprise at least one
of a first type subframe including 6 OFDMA (orthogonal frequency division multiple
access) symbols or a second type subframe including 7 OFDMA symbols.




A method of transmitting a signal using a prescribed frame structure in a wireless
communication system is disclosed. A mobile station is able to transmit or receive a signal
using a frame structure with a CP length corresponding to 1/4 of a useful symbol. Moreover,
the mobile station is able to transmit or receive a signal using a frame structure with a CP
length corresponding to 1/4 of a useful symbol, which is designed to mutually coexist
without causing collision or interference with another frame structure with a different CP
length. In this case, a channel bandwidth of the prescribed frame structure is 8.75 MHz.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=XyxDoZDXbtRtW2OLuBdqWA==&loc=wDBSZCsAt7zoiVrqcFJsRw==


Patent Number 271894
Indian Patent Application Number 360/KOL/2010
PG Journal Number 11/2016
Publication Date 11-Mar-2016
Grant Date 09-Mar-2016
Date of Filing 31-Mar-2010
Name of Patentee LG ELECTRONICS INC.
Applicant Address 20, YEOUIDO-DONG, YEONGDEUNGPO-GU, SEOUL, 150-721 REPUBLIC OF KOREA
Inventors:
# Inventor's Name Inventor's Address
1 LIM, DONG GUK LG INSTITUTE, # 533 HOGYE 1(IL)-DONG, DONGAN-GU, ANYANG-SI, GYEONGGI-DO, 431-749 REPUBLIC OF KOREA
2 MOON, SUNG HO LG INSTITUTE, # 533 HOGYE 1(IL)-DONG, DONGAN-GU, ANYANG-SI, GYEONGGI-DO, 431-749 REPUBLIC OF KOREA
3 CHO, HAN GYU LG INSTITUTE, # 533 HOGYE 1(IL)-DONG, DONGAN-GU, ANYANG-SI, GYEONGGI-DO, 431-749 REPUBLIC OF KOREA
4 KWAK, JIN SAM LG INSTITUTE, # 533 HOGYE 1(IL)-DONG, DONGAN-GU, ANYANG-SI, GYEONGGI-DO, 431-749 REPUBLIC OF KOREA
5 KWON, YEONG HYEON LG INSTITUTE, # 533 HOGYE 1(IL)-DONG, DONGAN-GU, ANYANG-SI, GYEONGGI-DO, 431-749 REPUBLIC OF KOREA
PCT International Classification Number H04J3/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10-2009-0067849 2009-07-24 U.S.A.
2 61/166,252 2009-04-03 U.S.A.
3 61/218,047 2009-06-17 U.S.A.
4 61/173,214 2009-04-28 U.S.A.