METHOD AND APPARATUS FOR PERFORMING
FRACTIONAL SUBFRAME TRANSMISSION
FIELD OF THE INVENTION
[0001] Embodiments of the present invention generally relate to communication
techniques. More particularly, embodiments of the present invention relate to a
method and apparatus for performing fractional subframe transmission.
BACKGROUND OF THE INVENTION
[0002] In 3rd Generation Partnership Project (3GPP), the network structure and various
technologies needed for a terminal's movement between a 3GPP wireless
communication network and a Wireless Local Area Network (WLAN) network are
called interworking WLAN. The multi-mode wireless communication technology has
evolved to use multiple wireless communication technologies at the same time. The
use of multiple wireless communication technologies simultaneously thereby increases
transfer rates per unit time or improves the reliability of the terminal.
[0003] In wireless communication, the spectrum is very rare resource. A licensed band
represents a frequency band that is exclusively licensed to a specific operator to provide
specific wireless services. On the other hand, an unlicensed band represents a
frequency band that is not allocated to a specific operator, but is opened so that all
entities meeting the predefined requirements may use the frequency band.
[0004] In some regions in the world, unlicensed band technologies need to abide to
certain regulations, for example, Listen-Before-Talk (LBT), and channel bandwidth
occupancy requirements. LBT results in an uncertainty of channel availability. For
instance, an unlicensed band may be available at any time during a subframe.
[0005] WLAN that uses Wireless Fidelity (WiFi) is the typical wireless communication
technology used in the unlicensed band. Time granularity of current Long Term
Evolution (LTE) is much larger than that of WiFi, which leads to the low competitive
strength of License Assisted Access (LAA) with LBT As such, fair coexistence
between LTE and other technologies such as WiFi as well as between LTE operators is
expected.
[0006] In order to be more competitive in the unlicensed band, there is a need to
perform fractional subframe transmission with low signaling overhead and high
resource utilization.
SUMMARY OF THE INVENTION
[0007] The present invention proposes a solution regarding fractional subframe
transmission. Specifically, the present invention provides a method and apparatus for
fractional subframe transmission with low signaling overhead and high resource
utilization.
[0008] According to a first aspect of embodiments of the present invention,
embodiments of the invention provide a method for performing fractional subframe
transmission. The method may comprise: in response to detecting that a channel
becomes available, determining a target position from at least one potential position
predefined in a subframe; and performing the fractional subframe transmission from the
target position. The method may be performed at a transmitter.
[0009] According to a second aspect of embodiments of the present invention,
embodiments of the invention provide a method for performing fractional subframe
transmission. The method may comprise: determining a target position from at least
one potential position predefined in a subframe, the fractional subframe transmission
starting at the target position; and receiving the fractional subframe transmission from
the target position. The method may be performed at a receiver.
[0010] According to a third aspect of embodiments of the present invention,
embodiments of the invention provide an apparatus for performing fractional subframe
transmission. The apparatus may comprise: a first determining unit configured to in
response to detecting that a channel becomes available, determine a target position from
at least one potential position predefined in a subframe; and a performing unit
configured to perform the fractional subframe transmission from the target position.
The apparatus may be implemented at a transmitter.
[0011] According to a fourth aspect of embodiments of the present invention,
embodiments of the invention provide an apparatus for performing fractional subframe
transmission. The apparatus may comprise: a second determining unit configured to
determine a target position from at least one potential position predefined in a subframe,
the fractional subframe transmission starting at the target position; and a receiving unit
configured to receive the fractional subframe transmission from the target position.
The apparatus may be implemented at a receiver.
[0012] Other features and advantages of the embodiments of the present invention will
also be apparent from the following description of specific embodiments when read in
conjunction with the accompanying drawings, which illustrate, by way of example, the
principles of embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Embodiments of the invention are presented in the sense of examples and their
advantages are explained in greater detail below, with reference to the accompanying
drawings, where
[0014] FIG. 1 illustrates a flow chart of a method 100 for performing fractional
subframe transmission at a transmitter according to an embodiment of the invention;
[0015] FIG. 2 illustrates a flow chart of a method 200 for performing fractional
subframe transmission at a transmitter according to another embodiment of the
invention;
[0016] FIG. 3 illustrates a flow chart of a method 300 for performing fractional
subframe transmission at a receiver according to an embodiment of the invention;
[0017] FIG. 4 illustrates a flow chart of a method 400 for performing fractional
subframe transmission at a receiver according to another embodiment of the invention;
[0018] FIG. 5 illustrates a schematic diagram 500 of fractional subframe transmission
according to embodiments of the invention;
[0019] FIG. 6 illustrates a schematic diagram 600 of fractional subframe transmission
according to embodiments of the invention;
[0020] FIG. 7 illustrates a block diagram of an apparatus 700 for performing fractional
subframe transmission according to embodiments of the invention; and
[0021] FIG. 8 illustrates a block diagram of an apparatus 800 for performing fractional
subframe transmission according to embodiments of the invention.
[0022] Throughout the figures, same or similar reference numbers indicate same or
similar elements.
DETAILED DESCRIPTION OF EMBODIMENTS
[0023] The subject matter described herein will now be discussed with reference to
several example embodiments. It should be understood these embodiments are
discussed only for the purpose of enabling those skilled persons in the art to better
understand and thus implement the subject matter described herein, rather than
suggesting any limitations on the scope of the subject matter.
[0024] The terminology used herein is for the purpose of describing particular
embodiments only and is not intended to be limiting of example embodiments. As
used herein, the singular forms "a," "an" and "the" are intended to include the plural
forms as well, unless the context clearly indicates otherwise. It will be further
understood that the terms "comprises," "comprising," "includes" and/or "including,"
when used herein, specify the presence of stated features, integers, steps, operations,
elements and/or components, but do not preclude the presence or addition of one or
more other features, integers, steps, operations, elements, components and/or groups
thereof.
[0025] It should also be noted that in some alternative implementations, the
functions/acts noted may occur out of the order noted in the figures. For example, two
functions or acts shown in succession may in fact be executed concurrently or may
sometimes be executed in the reverse order, depending upon the functionality/acts
involved.
[0026] Embodiments of the present invention are directed to a solution for performing
fractional subframe transmission. The solution may be carried out between a receiver
and a transmitter. In particular, upon detecting that a channel becomes available, the
transmitter may determine a target position from at least one potential position
predefined in a subframe and perform the fractional subframe transmission from the
target position. The receiver may determine a target position from the at least one
predefined potential position in a similar way and receive the fractional subframe
transmission from the target position. In this way, transmission may be performed
without introducing signalling overhead. Meanwhile, once a channel enters an idle
state, the transmission may start from the current subframe, instead of the next subframe.
As such, resource utilization is improved.
[0027] In embodiments of the present invention, a fractional subframe may refer to a
subframe for downlink transmission or a subframe for uplink transmission, wherein one
part of the fractional subframe is used for transmission of control information or data
and the other part is not used for the transmission. For example, for a downlink
subframe comprising 14 symbols, if only the last 6 symbols are available for in the
downlink transmission while the first 8 symbols are unavailable, this subframe may be
considered as a factional subframe.
[0028] In the disclosure, the fractional subframe transmission may refer to the
transmission performed on one or more subframes, and at least one of the one or more
subframes is a fractional subframe. By way of example, the fractional subframe
transmission may comprise various cases, such as the first subframe being a fractional
subframe, the last subframe being a fractional subframe, both the first and the last
subframes being fractional subframes, and the like.
[0029] In some embodiments, the fractional subframe transmission may be downlink or
uplink cellular transmission. In downlink transmission, the receiver may comprise
user equipment (UE), such as a terminal, a Mobile Terminal (MT), a Subscriber Station
(SS), a Portable Subscriber Station (PSS), Mobile Station (MS), or an Access Terminal
(AT). Meanwhile, the transmitter may comprise a base station (BS), such as a node B
(NodeB or NB), or an evolved NodeB (eNodeB or eNB). In uplink transmission, the
transmitter may comprise a UE and the receiver may comprise a BS.
[0030] According to some other embodiments of the present invention, the fractional
subframe transmission may be D2D transmission. In this regard, the receiver may be a
Device-to-Device (D2D) receiver and the transmitter may be a D2D transmitter.
[0031] Embodiments of the present invention may be applied in various communication
systems, including but not limited to a Long Term Evolution (LTE) system or a Long
Term Evolution Advanced (LTE-A) system. Given the rapid development in
communications, there will of course also be future type wireless communication
technologies and systems with which the present invention may be embodied. It
should not be seen as limiting the scope of the invention to only the aforementioned
system.
[0032] Now some exemplary embodiments of the present invention will be described
below with reference to the figures. Reference is first made to FIG. 1, which illustrates
a flow chart of a method 100 for performing fractional subframe transmission at a
transmitter according to an embodiment of the invention. The method 100 may be
performed at a transmitter, such as a BS, a D2D transmitter, and other suitable device.
[0033] The method 100 starts at step SI 10, in which in response to detecting that a
channel becomes available, a target position is determined from at least one potential
position predefined in a subframe.
[0034] According to embodiments of the present invention, a subframe may comprise a
plurality of symbols. By way of example, a subframe may be 1ms and comprise 14
symbols, for example, symbols 0 to 13. A position, such as a potential position, a
target position, a current position, a next position, may refer to a time point or a time
period in the subframe. In some embodiments, a position may correspond to an instant
in a subframe. As an alternative, a position may correspond to a symbol of a subframe.
In this regard, the position may occupy a time period, for example, the time period of a
symbol. In the context, a target position may refer to a position from which the
fractional transmission may start, and a potential position may refer to a predefined
position that is a candidate of the target position.
[0035] According to embodiments of the present invention, there may be one or more
potential positions predefined in a subframe. Each of the potential positions may
correspond to a symbol of the subframe periodically or aperiodically. In some
embodiments, the potential positions may comprise every three symbols, for example,
symbols 0, 3, 6, 9 and 12. For instance, the potential positions may be set at
mod (N, Nd) = x ( [0,Nd-l]), (1)
where N represents the index of a symbol in a subframe, and Nd represents the interval
between two potential positions and may be an integer ranged from 1 to the total
number of symbols in the subframe, for example 14. According to equation (1), it may
be determined that the smaller the Nd is, the denser the potential positions are. In
some embodiments, each symbol in a subframe may be predefined as a potential
position.
[0036] It is to be noted that the above examples are illustrated for example, rather than
limitation. It can be appreciated that, in alternative embodiments, there may be
aperiodic configurations of the potential positions. For instance, the potential positions
may correspond to the symbols 0, 3, 8 and 12.
[0037] According to embodiments of the present invention, Clear Chanel Assessment
(CCA) or Extended Clear Chanel Assessment (eCCA) may be performed. With the
CCA/eCCA, the transmitter may detect whether a channel is available. In response to
detecting that the channel becomes available, the transmitter may determine the target
position from one or more potential positions in several ways. In some embodiments,
whether a current position is a potential position is detected first. If the current
position is a potential position, the potential position may be determined as the target
position; otherwise, a channel occupation signal may be transmitted from the current
position until a potential position and then the potential position may be determined as
the target position.
[0038] At step SI20, the fractional subframe transmission is performed from the target
position.
[0039] According to embodiments of the present invention, at step SI20, the transmitter
may send an indicator at the target position to a receiver. The indicator may indicate a
size of control information of the fractional subframe transmission, for example, the
number of symbols of Physical Downlink Control Channel (PDCCH). In some
embodiments, the indicator may be implemented as Physical Control Format Indicator
Channel (PCFICH), or any other suitable indicator. Upon receiving the indicator, the
receiver may know the size of the control information. For example, when the receiver
detects PCFICH, it may have the knowledge of the number symbols of PDCCH. It is
to be noted that the above example is shown only for illustration purpose, without
suggesting any limitations on the scope of the subject matter described herein. As can
be appreciated, in some embodiments, the control information may be configured by
higher layer signaling or configured according to specification(s).
[0040] According to embodiments of the present invention, at step SI20, the transmitter
may determine the number of available symbols in the subframe based on the target
position, and transmit control information and data of the fractional subframe
transmission from the target position based on the number of the available symbols. In
some embodiments, the control information may be transmitted on PDCCH, and the
data may be transmitted on Physical Downlink Shared Channel (PDSCH). Details of
the embodiments will be described with reference to FIG. 2.
[0041] According to embodiments of the present invention, the scheduling information
associated with each of the potential position may be preconfigured in advance. When
performing the fractional subframe transmission, the transmitter may obtain the
preconfigured scheduling information associated with the target position, and perform
the fractional subframe transmission based on the preconfigured scheduling information.
As such, upon determining the target position, the transmitter does not have to spend
much time on configuring scheduling information associated with the target position.
In this way, the fractional subframe transmission may be performed more quickly and
efficiently.
[0042] FIG. 5 illustrates a schematic diagram 500 of fractional subframe transmission
according to embodiments of the invention. FIG. 5 exemplarily shows four subframes,
subframes 0 to 3. With respect to subframe 0, there are three potential positions 521,
522 and 523, wherein the first potential position 521 corresponds to the start of
subframe 0, for example, symbol 0 of subframe 0. CCA/eCCA 501 may start from the
first potential position 521. During the CCA/eCCA 501, the transmitter may
determine that the channel is available at a position 524. Since the position 524 is not
a potential position, the transmitter may transmit channel occupation signals from the
position 524 until a potential position, for example, the potential position 522, and
determine the potential position 522 as the target position. The factional subframe
transmission then may start from the target position, wherein control information may
be transmitted on PDCCH at time periods 503, 505, 507 and 509, and data may be
transmitted on PDSCH at time periods 504, 506, 508 and 510.
[0043] Reference is now made to FIG. 2, which illustrates a flow chart of a method 200
for performing fractional subframe transmission at a transmitter according to another
embodiment of the invention. The method 200 may be considered as a specific
implementation of the method 100 described above with reference to Fig. 1. However,
it is noted that this is only for the purpose of illustrating the principles of the present
invention, rather than limiting the scope thereof.
[0044] Method 200 begins at step S210, in which a channel is detected as becoming
available.
[0045] According to embodiments of the present invention, whether a channel is
available may be detected in several ways, such as energy detection, carrier sensing, and
so on. In some embodiments, strength of energy from a further transmitter may be
measured on the channel. The further transmitter may be a transmitter that may use
the same channel and is different from the transmitter performing the method according
to embodiments of the present invention. If the energy strength is not strong, it may be
determined that the channel is idle. In this regard, the energy strength may be
compared with a strength threshold. In response to that the measured strength is less
than the strength threshold, the channel may be determined as being available. The
strength threshold may be a predetermined threshold, which may be set according to
system requirements, specifications, channel quality, and so on. According to
embodiments of the present invention, the strength threshold may be set as a fixed value
or a value that is changed dynamically. It is to be understood that the above example
embodiments are only for the purpose of illustration, without suggesting any limitations
on the subject matter described herein. The strength threshold may be implemented in
any other suitable ways.
[0046] Alternatively, the channel availability may be detected based on carrier sensing.
By way of example, a signalling from a further transmitter may be detected on the
channel. The further transmitter may be a transmitter that may use the channel and is
different from the transmitter performing the method according to embodiments of the
present invention. Based on the signalling, whether the channel is available may be
determined.
[0047] It is to be noted although the above embodiments illustrate a further transmitter,
there may be a plurality of further transmitters in a communication system according to
embodiments of the present invention. In such embodiments, energy detection and
carrier sensing may be performed with respect to the plurality of further transmitters.
[0048] At step S220, whether a current position is a potential position is detected.
[0049] If the current position is a potential position, the flow goes to step S240, where
the potential position is determined as the target position. If the current position is not
a potential position, the flow goes to step S230, where a channel occupation signal is
transmitted from the current position until a potential position. Then, the flow goes to
step S240, where the potential position is determined as the target position.
[0050] At step S250, a number of available symbols in the subframe are determined
based on the target position.
[0051] In some embodiments, the number of available symbols may be determined
based on the target position and the total number of symbols in a subframe. By way of
example, if there are 14 symbols in one subframe, and if the target position corresponds
to the sixth symbol, that is, symbol 5, it may be determined that there are 8 available
symbols, i.e., symbols 6 to 13. For another example, if there are 12 symbols in one
subframe, and if the target position corresponds to the eighth symbol, that is, symbol 7,
it may be determined that there are 4 available symbols, i.e., symbols 8 to 11.
[0052] At step S260, control information and/or data of the fractional subframe
transmission are transmitted from the target position based on the number of the
available symbols.
[0053] In some embodiments, if the channel is available in earlier symbols of a
subframe, for example, symbol 0 to 6, normal control information, for example normal
PDCCH, may be applied. If the channel is available in latter symbols of a subframe,
for example, symbol 9 to 13, shortened control information, for example shortened
PDCCH, may be applied. In an exemplary embodiment, the normal PDCCH may
occupy 3 symbols and the shortened PDCCH may occupy 1 or 2 symbols.
[0054] Additionally, in some embodiments, responsive to the number of the available
symbols is less than or equal to a predetermined threshold, the transmitter may transmit
the control information and the data in the available symbols of the subframe and a
subframe immediately following the subframe. In an exemplary embodiment, if the
number of the available symbols is equal to the size of the control information, the
transmitter may transmit the control information in the available symbols of the
subframe and transmit the data in a subframe immediately following the subframe. In
a further exemplary embodiment, if the number of the available symbols is less than the
size of the control information, the transmitter may transmit a first part of the control
information in the available symbols of the subframe and a second part of the control
information in a further subframe immediately following the subframe, wherein the first
part and the second part constitute the control information. After the control
information is transmitted, the transmitter may transmit the data in the further subframe.
According to embodiments of the present invention, the predetermined threshold may
be set as a fixed value or a value that is changed dynamically, and may be configured by
high layer signalling or prescribed by specifications. In an exemplary embodiment,
the predetermined threshold may be set as 3.
[0055] FIG. 6 illustrates a schematic diagram 600 of fractional subframe transmission
according to embodiments of the invention. FIG. 6 exemplarily shows four subframes,
subframes 0 to 3. With respect to subframe 0, there are two potential positions 621
and 622. CCA/eCCA 601 may start from the first potential position 621. During
CCA/eCCA 601, the transmitter may determine that the channel is available at the
potential position 622. Thus, the potential position 622 may be determined as the
target position. The factional subframe transmission then may start from the target
position, wherein control information may be transmitted on PDCCH at time periods
602, 603 and 605, and data may be transmitted on PDSCH at time periods 604 and 606.
As shown in FIG. 6, the control information is transmitted in the available symbols of
the subframe 0 and its following subframe 1, corresponding to the time periods 602 and
603 respectively. After the control information, the data is transmitted at the time
period 604. In particular, the first part of the control information is transmitted at the
time period 602, and the second part of the control information is transmitted at the time
period 603.
[0056] It is to be noted that, the factional subframe transmission may ends at a portion
of a subframe or at a full subframe. According to embodiments shown in FIG. 5, the
factional subframe transmission ends at a position 525. Thus, a portion of subframe 3
is used for the factional subframe transmission. In this case, both the first subframe
(i.e., subframe 0) and the last subframe (i.e., subframe 3) are fractional subframes.
Alternatively, as shown in FIG. 6, the factional subframe transmission terminates at the
end of subframe 2. In other words, the factional subframe transmission ends at a full
subframe.
[0057] Additionally, in some embodiments, a transport block size in the fractional
subframe may be determined based on the number of the available symbols and the data
of the transport block size may be transmitted in the subframe.
[0058] The transport block size indicates the size of a data block to be transmitted in the
fractional subframe transmission. According to embodiments of the present invention,
the transport block size may be determined in various ways. In some embodiments,
the transmitter may determine a scaling factor associated with the number of the
available symbols, and then determine the transport block size based on the scaling
factor. The scaling factor may be defined in several ways. Table 1 illustrates an
example of scaling factors associated with different numbers of available symbols.
Table 1
[0059] In some embodiments, if the number of the available symbols is 1, 2 or 3, the
transmitter may use the available symbols to transmit control information of the
fractional subframe transmission, and may determine that the available symbols are not
enough for transmitting data after the transmission of the control information. In this
regard, the scaling factor may be designed as a value of "N/A", which indicates that the
scaling factor is "not available". In an exemplary embodiment, if the number of the
available symbols is 4, the transmitter may determine that the associated scaling factor
is 0.25. In an exemplary embodiment, if the number of the available symbols is 5, the
transmitter may determine that the associated scaling factor is 0.25 or 0.375. In an
exemplary embodiment, if the number of the available symbols is 6, the transmitter may
determine that the associated scaling factor is 0.375. In an exemplary embodiment, if
the number of the available symbols is 7, the transmitter may determine that the
associated scaling factor is 0.375 or 0.5. In an exemplary embodiment, if the number
of the available symbols is 8, the transmitter may determine that the associated scaling
factor is 0.5 or 0.75. In an exemplary embodiment, if the number of the available
symbols is 9, 10, 1 1 or 12, the transmitter may determine that the associated scaling
factor is 0.75. In an exemplary embodiment, if the number of the available symbols is
13 or 14, the transmitter may determine that the associated scaling factor is 1.
[0060] In some embodiments, the transport block size may be determined based on the
scaling factor in several ways. By way of example, a first resource block number
which indicates a number of resource blocks allocated for transmission may be obtained.
For the transmitter, the first resource block number may be determined by the
transmitter in real time. Then, a second resource block number may be determined
based on the first resource block number and the scaling factor. In an exemplary
embodiment, the second resource block number may be determined as follows:
wherein N 'PRB represents the first resource block number, N PRB represents the second
resource block number, Factor represents the scaling factor.
[0061] Based on the second resource block number, the transport block size may be
determined. In some embodiments, a transport block size table may be used for
determining the transport block size. Table 2 illustrates an exemplary transport block
size table.
Table 2
15 280 600 904 1224 1544 1800 2152 2472 2728 3 112
16 328 632 968 1288 1608 1928 2280 2600 2984 3240
17 336 696 1064 1416 1800 2152 2536 2856 3240 3624
18 376 776 1160 1544 1992 2344 2792 3112 3624 4008
19 408 840 1288 1736 2152 2600 2984 3496 3880 4264
20 440 904 1384 1864 2344 2792 3240 3752 4136 4584
2 1 488 1000 1480 1992 2472 2984 3496 4008 4584 4968
22 520 1064 1608 2152 2664 3240 3752 4264 4776 5352
23 552 128 1736 2280 2856 3496 4008 4584 5160 5736
24 584 1192 1800 2408 2984 3624 4264 4968 5544 5992
25 616 1256 1864 2536 3112 3752 4392 5160 5736 6200
26 712 1480 2216 2984 3752 4392 5160 5992 6712 7480
[0062] The horizontal direction of Table 2 may correspond to a resource block number,
for example, the second resource block number in the embodiments, and the vertical
direction may correspond to a Modulation and Coding Scheme (MCS). In the
embodiments, when the transmitter determines the second resource block number as
well as the MCS that is employed currently, it may determine the transport block size by
looking up the Table 2 based on the second resource block number and the MCS. By
way of example, if the second resource block number is 8, and the MCS is 8 the
transport block size may be determined as 1096.
[0063] It is to be noted that although the dimension of Table 2 is 10 X 27, it is
simplification of 3GPP TS36.213 whose dimension is 34X 110. It is further to be
noted that the above example table is only for the purpose of illustration, without
suggesting any limitations on the subject matter described herein. Any other suitable
table may be used in the determination of the transport block size.
[0064] Reference is now made to FIG. 3, which illustrates a flow chart of a method 300
for performing fractional subframe transmission at a receiver according to an
embodiment of the invention. The method 300 may be performed at a receiver, such
as a UE, a D2D receiver, and other suitable device.
[0065] At step S3 10, a target position is determined from at least one potential position
predefined in a subframe, the fractional subframe transmission starting at the target
position.
[0066] According to embodiments of the present invention, there may be at least one
potential position predefined in a subframe. In some embodiments, a plurality of
potential positions may periodically correspond to symbols of the subframe, for
example according to equation (1). Alternatively, there may be aperiodic
configurations of the potential positions. For instance, the potential positions may
correspond to the symbols 3, 8 and 12.
[0067] The target position indicates when the fractional subframe transmission starts.
There may be several ways for the receiver to determine the target position based on
one or more potential positions predefined in the subframe. In some embodiments, the
transmitter may send an indicator at the target position to a receiver, wherein the
indicator, for example PCFICH, may indicate a size of control information of the
fractional subframe transmission. In this way, the target position may be indicated
explicitly. For the receiver, it may detect the indicator at one of the at least one
potential position, for example, denoted as potential position 1. In response to that the
indicator is detected, the receiver may determine the one of the at least one potential
position as the target position. Otherwise, the receiver may determine that this
potential position is not the target position and carry out the same detection on a further
potential position, for example potential position 2, and so on.
[0068] Alternatively, in some embodiments, the transmitter may not send the indicator.
In this case, the receiver may make blind decoding for control information of the
fractional subframe transmission at one of the at least one potential position. In
response to that the blind decoding is success, the receiver may determine the one of the
at least one potential position as the target position.
[0069] At step S320, the fractional subframe transmission is received from the target
position.
[0070] In some embodiments, based on the indicator indicating the size of control
information of the fractional subframe transmission, the receiver may know the size of
the control information and accordingly receive the control information from the target
position.
[0071] According to embodiments of the present invention, a number of available
symbols in the subframe may be determined based on the target position, and the
control information and data of the fractional subframe transmission may be received
based on the number of the available symbols. In some embodiments, during the
fractional subframe transmission, the control information may be transmitted before the
data. In this case, the receiver may receive control information prior to the data. In
some alternative embodiments, it is possible that the data is transmitted before the
control information. As such, the receiver may receive the data prior to the control
information. Details will be discussion with reference to embodiments of FIG. 4.
[0072] FIG. 4 illustrates a flow chart of a method 400 for performing fractional
subframe transmission at a receiver according to another embodiment of the invention.
The method 400 may be considered as a specific implementation of the method 300
described above with reference to Fig. 3. However, it is noted that this is only for the
purpose of illustrating the principles of the present invention, rather than limiting the
scope thereof.
[0073] At step S410, an indicator is detected at one of the at least one potential position,
the indicator indicating a size of control information of the fractional subframe
transmission.
[0074] In some embodiments, the transmitter may send an indicator, for example
PCFICH, at the target position to a receiver, to indicate a size of control information of
the fractional subframe transmission. In this case, the receiver may detect the indicator
at one of the at least one potential position. At step S420, in response to that the
indicator is detected, the one of the at least one potential position is determined as the
target position. Otherwise, the receiver may detect the indicator at a further potential
position.
[0075] At step S430, a number of available symbols in the subframe is determined
based on the target position.
[0076] This step is similar to step S250. In some embodiments, the number of
available symbols may be determined based on the target position and the total number
of symbols in a subframe. By way of example, if there are 14 symbols in one
subframe, and if the target position corresponds to the sixth symbol, that is, symbol 5, it
may be determined that there are 8 available symbols, i.e., symbols 6 to 13. For
another example, if there are 12 symbols in one subframe, and if the target position
corresponds to the eighth symbol, that is, symbol 7, it may be determined that there are
4 available symbols, i.e., symbols 8 to 11.
[0077] At step S440, control information and data of the fractional subframe
transmission are received based on the number of the available symbols.
[0078] In some embodiments, responsive to the number of the available symbols is less
than or equal to a predetermined threshold, the receiver may receive the control
information and the data in the available symbols and a subframe immediately
following the subframe. In an exemplary embodiment, if the number of the available
symbols is equal to the size of the control infonnation, the receiver may receive the
control information in the available symbols of the subframe and receive the data in a
subframe immediately following the subframe. In a further exemplary embodiment, if
the number of the available symbols is less than the size of the control information, the
receiver may receive a first part of the control information in the available symbols of
the subframe and a second part of the control information in a further subframe
immediately following the subframe, wherein the first part and the second part
constitute the control information. After the control information is received, the
receiver may receive the data in the further subframe.
[0079] Additionally, in some embodiments, a transport block size in the subframe may
be determined based on the number of the available symbols. Then, the data of the
transport block size may be received in the subframe.
[0080] The transport block size indicates the size of a data block to be transmitted in the
fractional subframe transmission. According to embodiments of the present invention,
the transport block size may be determined in various ways. In some embodiments,
the receiver may determine a scaling factor associated with the number of the available
symbols, and then determine the transport block size based on the scaling factor. The
scaling factor may be defined in several ways. As discussed above, Table 1 illustrates
an example of scaling factors associated with different numbers of available symbols.
[0081] In an exemplary embodiment, if the number of the available symbols is 1, 2 or 3,
the receiver may determine that there is no data transmitted and there is no need to
determine the transport block size. In an exemplary embodiment, if the number of the
available symbols is 4, the receiver may determine that the associated scaling factor is
0.25. In an exemplary embodiment, if the number of the available symbols is 5, the
receiver may determine that the associated scaling factor is 0.25 or 0.375. In an
exemplary embodiment, if the number of the available symbols is 6, the receiver may
determine that the associated scaling factor is 0.375. In an exemplary embodiment, if
the number of the available symbols is 7, the receiver may determine that the associated
scaling factor is 0.375 or 0.5. In an exemplary embodiment, if the number of the
available symbols is 8, the receiver may determine that the associated scaling factor is
0.5 or 0.75. In an exemplary embodiment, if the number of the available symbols is 9,
10, 1 1 or 12, the receiver may determine that the associated scaling factor is 0.75. In
an exemplary embodiment, if the number of the available symbols is 13 or 14, the
receiver may determine that the associated scaling factor is 1.
[0082] In some embodiments, the transport block size may be determined based on the
scaling factor in several ways. By way of example, a first resource block number
which indicates a number of resource blocks allocated for transmission may be obtained.
For the receiver, the first resource block number may be notified by the transmitter.
Then, a second resource block number may be determined based on the first resource
block number and the scaling factor. In an exemplary embodiment, the second
resource block number may be determined according to equation (2). Based on the
second resource block number, the transport block size may be determined. In some
embodiments, a transport block size table, for example Table 2, may be used for
determining the transport block size. In particular, if the receiver determines the
second resource block number as well as the MCS which is employed currently, it may
determine the transport block size by looking up the Table 2.
[0083] FIG. 7 illustrates a block diagram of an apparatus 700 for performing fractional
subframe transmission according to embodiments of the invention. In accordance with
embodiments of the present invention, the apparatus 700 may be implemented at a
transmitter, for example, a BS, a D2D transmitter or any other applicable device.
[0084] As shown, the apparatus 700 comprises: a first determining unit 710 configured
to in response to detecting that a channel becomes available, determine a target position
from at least one potential position predefined in a subframe; and a performing unit 720
configured to perform the fractional subframe transmission from the target position.
[0085] According to embodiments of the present invention, the first determining unit
710 may comprise: a potential position detecting unit configured to detect whether a
current position is a potential position; and a first target position determining unit
configured to responsive to that the current position is a potential position, determine
the potential position as the target position, and responsive to that the current position is
not a potential position, transmit a channel occupation signal from the current position
until a potential position and determine the potential position as the target position.
[0086] According to embodiments of the present invention, each of the at least one
potential position may correspond to a symbol of the subframe periodically or
aperiodically.
[0087] According to embodiments of the present invention, the performing unit 720
may comprise: a sending unit configured to send an indicator at the target position, the
indicator indicating a size of control information of the fractional subframe
transmission.
[0088] According to embodiments of the present invention, the performing unit 720
may comprise: a first available symbol number determining unit configured to
determine a number of available symbols in the subframe based on the target position;
and a transmitting unit configured to transmit control information and data of the
fractional subframe transmission from the target position based on the number of the
available symbols.
[0089] In some embodiments, the transmitting unit may be further configured to:
responsive to the number of the available symbols is less than or equal to a
predetermined threshold, transmit the control information and the data in the available
symbols and a subframe immediately following the subframe.
[0090] In some embodiments, the transmitting unit may comprise: a size determining
unit configured to determine a transport block size in the subframe based on the number
of the available symbols, wherein the transmitting unit may be further configured to
transmit the data of the transport block size in the subframe.
[0091] According to embodiments of the present invention, the performing unit 720
may comprise: a scheduling information obtaining unit configured to obtain
preconfigured scheduling information associated with the target position, wherein the
performing unit may be further configured to perform the fractional subframe
transmission based on the preconfigured scheduling information.
[0092] FIG. 8 illustrates a block diagram of an apparatus 800 for performing fractional
subframe transmission according to embodiments of the invention. In accordance with
embodiments of the present invention, the apparatus 800 may be implemented at a
receiver, for example, a cellular UE, a D2D receiver or any other applicable device.
[0093] As shown, the apparatus 800 comprises: a second determining unit 810
configured to determine a target position from at least one potential position predefined
in a subframe, the fractional subframe transmission starting at the target position; and a
receiving unit 820 configured to receive the fractional subframe transmission from the
target position.
[0094] According to embodiments of the present invention, the second determining unit
810 may comprise: an indicator detecting unit configured to detect an indicator at one of
the at least one potential position, the indicator indicating a size of control information
of the fractional subframe transmission; and a second target position determining unit
configured to in response to that the indicator is detected, determine the one of the at
least one potential position as the target position.
[0095] According to embodiments of the present invention, the second determining unit
810 may comprise: a decoding unit configured to make blind decoding for control
information of the fractional subframe transmission at one of the at least one potential
position; and a third target position determining unit configured to in response to that
the blind decoding is success, determine the one of the at least one potential position as
the target position.
[0096] According to embodiments of the present invention, each of the at least one
potential position may correspond to a symbol of the subframe periodically or
aperiodically.
[0097] According to embodiments of the present invention, the receiving unit 820 may
comprise: a second available symbol number determining unit configured to determine
a number of available symbols in the subframe based on the target position, wherein the
receiving unit may be further configured to receive control information and data of the
fractional subframe transmission based on the number of the available symbols.
[0098] According to embodiments of the present invention, the receiving unit 820 may
be further configured to responsive to the number of the available symbols is less than
or equal to a predetermined threshold, receive the control information and the data in
the available symbols and a subframe immediately following the subframe.
[0099] According to embodiments of the present invention, the receiving unit 820 may
comprise: a size determining unit configured to determine a transport block size in the
subframe based on the number of the available symbols, wherein the receiving unit may
be further configured to receive the data of the transport block size in the subframe.
[00100] It is also to be noted that the apparatuses 700 and 800 may be respectively
implemented by any suitable technique either known at present or developed in the
future. Further, a single device shown in FIG. 7 or FIG. 8 may be alternatively
implemented in multiple devices separately, and multiple separated devices may be
implemented in a single device. The scope of the present invention is not limited in
these regards.
[00101] It is noted that the apparatus 700 may be configured to implement
functionalities as described with reference to FIGs.1-2, and the apparatus 800 may be
configured to implement functionalities as described with reference to FIGs. 3-4.
Therefore, the features discussed with respect to the method 100 or 200 may apply to
the corresponding components of the apparatus 700, and the features discussed with
respect to the method 300 or 400 may apply to the corresponding components of the
apparatus 800. It is further noted that the components of the apparatus 700 or the
apparatus 800 may be embodied in hardware, software, firmware, and/or any
combination thereof. For example, the components of the apparatus 700 or the
apparatus 800 may be respectively implemented by a circuit, a processor or any other
appropriate device. Those skilled in the art will appreciate that the aforesaid examples
are only for illustration not limitation.
[00102] In some embodiment of the present disclosure, the apparatus 700 or the
apparatus 800 may comprise at least one processor. The at least one processor suitable
for use with embodiments of the present disclosure may include, by way of example,
both general and special purpose processors already known or developed in the future.
The apparatus 700 or the apparatus 800 may further comprise at least one memory.
The at least one memory may include, for example, semiconductor memory devices,
e.g., RAM, ROM, EPROM, EEPROM, and flash memory devices. The at least one
memory may be used to store program of computer executable instructions. The
program can b e written in any high-level and/or low-level compilable or interpretable
programming languages. In accordance with embodiments, the computer executable
instructions may be configured, with the at least one processor, to cause the apparatus
700 to at least perform according to the method 100 or 200 as discussed above, or to
cause the apparatus 800 to at least perform according to the method 300 or 400 as
discussed above.
[00103] Based on the above description, the skilled in the art would appreciate that the
present disclosure may be embodied in an apparatus, a method, or a computer program
product. In general, the various exemplary embodiments may be implemented in
hardware or special purpose circuits, software, logic or any combination thereof. For
example, some aspects may be implemented in hardware, while other aspects may be
implemented in firmware or software which may be executed by a controller,
microprocessor or other computing device, although the disclosure is not limited thereto.
While various aspects of the exemplary embodiments of this disclosure may be
illustrated and described as block diagrams, flowcharts, or using some other pictorial
representation, it is well understood that these blocks, apparatus, systems, techniques or
methods described herein may be implemented in, as non-limiting examples, hardware,
software, firmware, special purpose circuits or logic, general purpose hardware or
controller or other computing devices, or some combination thereof.
[00104] The various blocks shown in FIGs. 1-4 may be viewed as method steps, and/or
as operations that result from operation of computer program code, and/or as a plurality
of coupled logic circuit elements constructed to carry out the associated function(s).
At least some aspects of the exemplary embodiments of the disclosures may be
practiced in various components such as integrated circuit chips and modules, and that
the exemplary embodiments of this disclosure may be realized in an apparatus that is
embodied as an integrated circuit, FPGA or ASIC that is configurable to operate in
accordance with the exemplary embodiments of the present disclosure.
[00105] While this specification contains many specific implementation details, these
should not be construed as limitations on the scope of any disclosure or of what may be
claimed, but rather as descriptions of features that may be specific to particular
embodiments of particular disclosures. Certain features that are described in this
specification in the context of separate embodiments can also be implemented in
combination in a single embodiment. Conversely, various features that are described
in the context of a single embodiment can also be implemented in multiple
embodiments separately or in any suitable sub-combination. Moreover, although
features may be described above as acting in certain combinations and even initially
claimed as such, one or more features from a claimed combination can in some cases be
excised from the combination, and the claimed combination may be directed to a
sub-combination or variation of a sub-combination.
[00106] Similarly, while operations are depicted in the drawings in a particular order,
this should not be understood as requiring that such operations be performed in the
particular order shown or in sequential order, or that all illustrated operations be
performed, to achieve desirable results. In certain circumstances, multitasking and
parallel processing may be advantageous. Moreover, the separation of various system
components in the embodiments described above should not be understood as requiring
such separation in all embodiments, and it should be understood that the described
program components and systems can generally be integrated together in a single
software product or packaged into multiple software products.
[00107] Various modifications, adaptations to the foregoing exemplary embodiments of
this disclosure may become apparent to those skilled in the relevant arts in view of the
foregoing description, when read in conjunction with the accompanying drawings.
Any and all modifications will still fall within the scope of the non-limiting and
exemplary embodiments of this disclosure. Furthermore, other embodiments of the
disclosures set forth herein will come to mind to one skilled in the art to which these
embodiments of the disclosure pertain having the benefit of the teachings presented in
the foregoing descriptions and the associated drawings.
[00108] Therefore, it is to be understood that the embodiments of the disclosure are not
to be limited to the specific embodiments disclosed and that modifications and other
embodiments are intended to be included within the scope of the appended claims.
Although specific terms are used herein, they are used in a generic and descriptive sense
only and not for purpose of limitation.

WHATIS CLAIMED IS:
.A method of performing fractional subframe transmission, comprising:
in response to detecting that a channel becomes available, determining a target
position from at least one potential position predefined in a subframe; and
performing the fractional subframe transmission from the target position.
2. The method of Claim 1, wherein in response to detecting that a channel becomes
available, determining a target position from at least one potential position predefined in
a subframe comprises:
detecting whether a current position is a potential position;
responsive to that the current position is a potential position, determining the
potential position as the target position; and
responsive to that the current position is not a potential position, transmitting a
channel occupation signal from the current position until a potential position and
determining the potential position as the target position.
3. The method of Claim 1, wherein each of the at least one potential position
corresponds to a symbol of the subframe periodically or aperiodically.
4. The method of Claim 1, wherein performing the fractional subframe
transmission from the target position comprises:
sending an indicator at the target position, the indicator indicating a size of control
information of the fractional subframe transmission.
5. The method of Claim 1, wherein performing the fractional subframe
transmission from the target position comprises:
determining a number of available symbols in the subframe based on the target
position; and
transmitting control information and data of the fractional subframe transmission
from the target position based on the number of the available symbols.
6. The method of Claim 5, wherein transmitting control information and data of the
fractional subframe transmission from the target position based on the number of the
available symbols comprises:
responsive to the number of the available symbols is less than or equal to a
predetermined threshold, transmitting the control information and the data in the
available symbols and a subframe immediately following the subframe.
7. The method of Claim 5, wherein transmitting control information and data of the
fractional subframe transmission from the target position based on the number of the
available symbols comprises:
determining a transport block size in the subframe based on the number of the
available symbols; and
transmitting the data of the transport block size in the subframe.
8. The method of Claim 1, wherein performing the fractional subframe
transmission from the target position comprises:
obtaining preconfigured scheduling information associated with the target position;
and
performing the fractional subframe transmission based on the preconfigured
scheduling information.
9.A method of performing fractional subframe transmission, comprising:
determining a target position from at least one potential position predefined in a
subframe, the fractional subframe transmission starting at the target position; and
receiving the fractional subframe transmission from the target position.
10. The method of Claim 9, wherein determining a target position from at least one
potential position predefined in a subframe comprises:
detecting an indicator at one of the at least one potential position, the indicator
indicating a size of control information of the fractional subframe transmission; and
in response to that the indicator is detected, determining the one of the at least one
potential position as the target position.
11. The method of Claim 9, wherein determining a target position from at least one
potential position in a subframe comprises:
making blind decoding for control information of the fractional subframe
transmission at one of the at least one potential position; and
in response to that the blind decoding is success, determining the one of the at least
one potential position as the target position.
12. The method of Claim 9, wherein each of the at least one potential position
corresponds to a symbol of the subframe periodically or aperiodically.
13. The method of Claim 9, wherein receiving the fractional subframe transmission
from the target position comprises:
determining a number of available symbols in the subframe based on the target
position; and
receiving control information and data of the fractional subframe transmission
based on the number of the available symbols.
14. The method of Claim 13, wherein receiving control information and data of the
fractional subframe transmission based on the number of the available symbols
comprises:
responsive to the number of the available symbols is less than or equal to a
predetermined threshold, receiving the control information and the data in the available
symbols and a subframe immediately following the subframe.
15. The method of Claim 13, wherein receiving control information and data of the
fractional subframe transmission based on the number of the available symbols
comprises:
determining a transport block size in the subframe based on the number of the
available symbols; and
receiving the data of the transport block size in the subframe.
16. An apparatus of performing fractional subframe transmission, comprising:
a first determining unit configured to in response to detecting that a channel
becomes available, deteraiine a target position from at least one potential position
predefined in a subframe; and
a performing unit configured to perform the fractional subframe transmission from
the target position.
17. The apparatus of Claim 16, wherein the first determining unit comprises:
a potential position detecting unit configured to detect whether a current position is
a potential position; and
a first target position determining unit configured to responsive to that the current
position is a potential position, determine the potential position as the target position,
and responsive to that the current position is not a potential position, transmit a channel
occupation signal from the current position until a potential position and determine the
potential position as the target position.
18. The apparatus of Claim 16, wherein each of the at least one potential position
corresponds to a symbol of the subframe periodically or aperiodically.
. The apparatus of Claim 1 , wherein the performing unit comprises:
a sending unit configured to send an indicator at the target position, the indicator
indicating a size of control information of the fractional subframe transmission.
20. The apparatus of Claim 16, wherein the performing unit comprises:
a first available symbol number determining unit configured to determine a number
of available symbols in the subframe based on the target position; and
a transmitting unit configured to transmit control information and data of the
fractional subframe transmission from the target position based on the number of the
available symbols.
21. The apparatus of Claim 20, wherein the transmitting unit is further configured
to:
responsive to the number of the available symbols is less than or equal to a
predetennined threshold, transmit the control information and the data in the available
symbols and a subframe immediately following the subframe.
22. The apparatus of Claim 20, wherein the transmitting unit comprises:
a size determining unit configured to determine a transport block size in the
subframe based on the number of the available symbols,
wherein the transmitting unit is further configured to transmit the data of the
transport block size in the subframe.
23. The apparatus of Claim 16, wherein the performing unit comprises:
a scheduling information obtaining unit configured to obtain preconfigured
scheduling information associated with the target position,
wherein the performing unit is further configured to perform the fractional
subframe transmission based on the preconfigured scheduling information.
24. An apparatus of performing fractional subframe transmission, comprising:
a second determining unit configured to determine a target position from at least
one potential position predefined in a subframe, the fractional subframe transmission
starting at the target position; and
a receiving unit configured to receive the fractional subframe transmission from
the target position.
25. The apparatus of Claim 24, wherein the second determining unit comprises:
an indicator detecting unit configured to detect an indicator at one of the at least
one potential position, the indicator indicating a size of control information of the
fractional subframe transmission; and
a second target position determining unit configured to in response to that the
indicator is detected, determine the one of the at least one potential position as the target
position.
26. The apparatus of Claim 24, wherein the second determining unit comprises:
a decoding unit configured to make blind decoding for control information of the
fractional subframe transmission at one of the at least one potential position; and
a third target position determining unit configured to in response to that the blind
decoding is success, determine the one of the at least one potential position as the target
position.
27. The apparatus of Claim 24, wherein each of the at least one potential position
corresponds to a symbol of the subframe periodically or aperiodically.
28. The apparatus of Claim 24, wherein the receiving unit comprises:
a second available symbol number determining unit configured to determine a
number of available symbols in the subframe based on the target position,
wherein the receiving unit is further configured to receive control information and
data of the fractional subframe transmission based on the number of the available
symbols.
29. The apparatus of Claim 28, wherein the receiving unit is further configured to
responsive to the number of the available symbols is less than or equal to a
predetermined threshold, receive the control information and the data in the available
symbols and a subframe immediately following the subframe.
30. The apparatus of Claim 28, wherein the receiving unit comprises:
a size determining unit configured to determine a transport block size in the
subframe based on the number of the available symbols,
wherein the receiving unit is further configured to receive the data of the transport
block size in the subframe.