[DESCRIPTION]
[Ti t le of Invent ion]
DATA TRANSMISSION APPARATUS, DATA DIVISION
APPARATUS AND DATA DIVISION METHOD
5
[Technical Field]
[0001] The present invent ion is related to a data t ransmission
apparatus, a data division apparatus and a data division method, and
part icular ly are related to a data transmission apparatus, a data division
10 apparatus and a data division method which divide transmission data into
blocks.
[Background Art]
[0002] In the case of packet transmission, a packet transmission
15 apparatus divides packet data, which are received f rom i ts preceding
communicat ion apparatus, into a plural i ty of blocks each having a fixed
block size (predetermined block size) , and assigns the blocks to a plural i ty
of t ransmission l ines . Accordingly, the packet t ransmission apparatus can
increase transmission capaci ty by use of the plural t ransmission l ines.
20 [0003] In the case that a size of the packet data, which are received
from the communicat ion apparatus, is not an integral mul t iple of the f ixed
data block size, if dividing the packet data into the blocks each having the
fixed block size, n (n is any integer ) blocks each having the f ixed block
size, and one block including residual data, whose size is smal ler than the
25 fixed block size, are generated.
[0004] In the case of a method according to a related art , by
car rying out a padding process in which dummy data are added to the
residual data, the packet t ransmission apparatus makes the size of the
residual data adjusted to the fixed block size. Then, the packet
3
transmission apparatus t ransfers data for which the padding process is
car ried out . The method has a problem that data transmission ef ficiency is
lowered, since the t ransfer red data includes a block which has an area
unused for data t ransmission.
[0005] In order to solve the problem, PTL 1 discloses an art to set 5 a
size of packet data, which are sent by a communicat ion apparatus, to be
equal to or smal ler than MTU (Maximum Transfer Uni t ) defined between
the communicat ion apparatus and a tran smission dest inat ion apparatus, and
to be an integral mul t iple of a block size which is appl ied to a low rank
10 transmission l ine. By using the method, i t is avoided to generate the
residual data in the division process carried out by the packet transmission
apparatus which receives the packet data from the communicat ion
apparatus. Therefore, i t is possible to avoid generat ion of the block which
includes the unused area.
15
[Ci tat ion List]
[Patent Li terature]
[0006] PTL 1 : Japanese Patent Appl icat ion Laid-Open
Publ icat ion No. 2002-084312
20
[Technical Problem]
[0007] According to the art disclosed in PTL 1, i t is assumed that
the communicat ion apparatus adjusts the size of the data packet , and
according to the art , a si tuat ion that the communicat ion apparatus sends
25 packet data, which has an opt ional size, to the packet transmission
apparatus is not taken into considerat ion. Accordingly, in the case that the
communicat ion apparatus sends the packet data, which has the opt ional
size, to the packet t ransmission apparatus, the residual data is generated in
the division process which is car ried out by the packet t ransmission
4
apparatus. Therefore, i t is not possible to rest rain generat ion of the block
including the unused area, and consequent ly the problem that packet
transmission ef ficiency is lowered st i l l remains.
[0008] The present invent ion is conceived to solve the problem. An
object of the present invent ion is to provide a data tran smission apparatus5 ,
a data division apparatus and a data division method which can make data
transmission ef ficient .
[Solut ion to Problem]
[0009] A f irst aspect of the present invent ion includes a data
10 transmission apparatus which divides transmission data into blocks each of
which has a predetermined data size, and transmi ts the blocks to a
transmission dest inat ion apparatus. The data t ra nsmission apparatus
includes: a transmission data division uni t which divides the
transmission data into the blocks; a t ransmission uni t which transmi ts
15 the blocks divided by the t ransmission data division uni t to the
transmission dest inat ion apparatus: a calculat ion uni t which calculates a
size of residual data generated by dividing the t ransmission data into the
blocks each having the predetermined data size; and a residual data
judgment uni t which judges whether the size of the residual data calculat ed
20 by the calculat ion uni t is smal ler or not smal ler than a minimum data size
which the t ransmission dest inat ion apparatus can receive. In the case that
the residual data judgment uni t judges that the size of the residual data is
smal ler than the minimum data size, the t ransmission data division uni t
generates a block, which includes the residual data and whose data size is
25 equal to or larger than the minimum data size, by dividing the transmission
data so as to make the block, which includes the residual d ata, include a
part of the t ransmission data other than the residual data.
[0010] A second aspect of the present invent ion includes a data
division apparatus which divides transmission data into blocks each of
5
which has a predetermined data size. The data division apparatus includes:
a t ransmission data division uni t which divides the transmission data into
the blocks; a calculat ion uni t which calculates a size of residual data
generated by dividing the transmission data into the blocks each having th e
predetermined data size; and a residual data judgment uni t which judge5 s
whether the size of residual data calculated by the calculat ion uni t is
smal ler or not smal ler than a minimum data size which a t ransmission
dest inat ion apparatus can receive. In th e case that the residual data
judgment uni t judges that the size of the residual data is smal ler than the
10 minimum data size, the transmission data division uni t generates a block,
which includes the residual data and whose data size is equal to or larger
than the minimum data size, by dividing the transmission data so as to
make the block, which includes the residual data, include a par t of the
transmission data other than the residual data.
15 [0011] A thi rd aspect of the present invent ion includes a data
division method used by a data division apparatus which divides
transmission data into blocks each of which has a predetermined data size.
The data division method includes the fol lowing steps (a), (b) and (c):
(a) calculat ing a size of residual data gen erated by dividing the
20 transmission data into the blocks each of which has the predetermined data
size;
(b) judging whether the calculated size of the residual data is
smal ler or not smal ler than a minimum data size which a t ransmission
dest inat ion apparatus can receive; and
25 (c) generat ing a block, which includes the residual data and whose
data size is equal to or larger than the minimum data size, by dividing the
transmission data so as to make the block, which includes the residual data,
include a par t of the transmission data other than the residual data, in the
case that i t is judged that the size of the residual data is smal ler than the
6
minimum data size.
[Advantageous Ef fects of Invent ion]
[0012] According to each aspect of the present invent ion , i t is
possible to provide the data transmission apparatus, the data division
apparatus and the data division method which can real ize ef ficient dat5 a
transmission.
[Brief Descript ion of Drawings]
[0013] [Fig. 1] is a block diagram showing a configurat i on example
of a data transmission apparatus according to an exemplary embodiment 1.
10 [Fig. 2] is a f lowchart showing an example of a process which is
car ried out by the data t ransmission apparatus according to the exemplary
embodiment 1.
[Fig. 3] is a block diagram showing an example of a wi reless
communicat ion system according to an exemplary embodiment 2.
15 [Fig. 4] is a block diagram showing a configurat ion example of a
packet data division circui t according to the exemplary embodiment 2.
[Fig. 5] is a block diagram showing a detai led conf igurat ion
example of a wi reless packet t ransmission apparatus according to the
exemplary embodiment 2.
20 [Fig. 6] is a f lowchart showing an example of a division process
method according to the exemplary embodiment 2.
[Fig. 7A] is a fi rst image diagram showing an example of a packet
data division method according to the exemplary embodiment 2.
[Fig. 7B] is a second image diagram showing an example of the
25 packet data division method according to the exemplary embodiment 2 .
[Fig. 7C] is a thi rd image diagram showing an example of the
packet data division method according to the exemplary embodiment 2.
[Fig. 8A] is a f irst image diagram showing detai ls of the packet data
division method according to the exemplary embodimen t 2.
7
[Fig. 8B] is a second image diagram showing detai ls of the packet
data division method according to the exemplary embodiment 2.
[Fig. 9A] is a fi rst image diagram showing a packet data division
method according to a related art .
[Fig. 9B] is a second image diagram showing the packet dat5 a
division method according to the related art .
[Fig. 10] is a block diagram showing an example of a wireless
communicat ion system according to an exemplary embodiment 3.
[Fig. 11] is a block diagram showing a detai led configurat ion
10 example of a wi reless packet t ransmission apparatus according to the
exemplary embodiment 3.
[Fig. 12] is a block diagram showing an example of a wireless
communicat ion system according to an exemplary embodiment 4.
15 [Descript ion of Embodiments]
[0014] Exemplary embodiment 1
Hereinaf ter, an exemplary embodiment according to the present
invent ion wi l l be explained wi th reference to drawing s.
[0015] Fig. 1 is a block diagram showing a configurat ion example
20 of a data transmission apparatus according to an exemplary embodiment 1.
A data t ransmission apparatus 10 is a data t ransmission apparatus which
divides transmission data, which a t ransmission data generat ion apparatus
1 generates, into blocks (block data) each having a predetermined data
size, and t ransmi ts the blocks to a receiving apparatus 2 (t ransmission
25 dest inat ion apparatus) . The data t ransmission apparatus 10 and the
receiving apparatus 2 are connected each other via a wi red or wireless
transmission l ine. The data t ransmission apparatus 10 includes a
transmission data division uni t 11, a transmission uni t 12, a calculat ion
uni t 13 and a residual data judgment uni t 14.
8
[0016] The t ransmission data division uni t 11 divides the
transmission data, which are generated by the transmi ssion data generat ion
apparatus 1, into the blocks. Detai ls of a division process, which is car ried
out by the transmission data division uni t 11, wi l l be de scribed later.
[0017] The t ransmission uni t 12 t ransmi ts transmission data divide5 d
by the transmission data division uni t 11 into blocks, to the receiving
apparatus 2.
[0018] The calculat ion uni t 13 calculates a size of residual data
generated by dividing the t ransmission data, which are generated by the
10 transmission data generat ion apparatus 1, in to the blocks each having the
predetermined data size. Here, the prede termined data size is a data size
which is set by a user. For example, the data size is a value depending on a
state of the t ransmission l ine between the data transmission apparatus 10
and the receiving apparatus 2. As one example of the predetermined data
15 size, a value of the data size is set to such a degree that t ransmission delay
is not caused on the transmission l ine.
[0019] The residual data judgment uni t 14 judges whether the size
of the residual data, which is calculated by the calculat ion uni t 133, is
smal ler or not smal ler than a minimum data size which the receiving
20 apparatus 2 can receive. Each uni t of the data t ransmission apparatus 10
ment ioned above is real ized by hardware such as IC ( Integrated Circui t ) or
the l ike, software such as appl icat ion sof tware or the l ike or the hardware
and the sof tware.
[0020] The t ransmission data generat ion apparatus 1 is an apparatus
25 which generates the t ransmission data and sends the t ra nsmission data to
the data t ransmission apparatus 10.
[0021] The receiving apparatus 2 receives the t ransmission data
divided into blocks, from the data t ransmission apparatus 10. Here, the
receiving apparatus 2 does not receive data, whose size is smal le r than the
9
minimum data size, as ef fect ive receiving data. Accordingly, in order to
transmi t the t ransmission data ef fect ively, i t is necessary for the data
transmission apparatus 10 to transmi t a block whose size is equal to or
larger than the minimum data size. The minimum data size is a value which
is set by a user and is smal ler than the predetermined data size ment ione5 d
above.
[0022] Detai ls of the division process which the t ransmission data
division uni t 11 carries out wi l l be explained in the fol lowing wi th
reference to Fig. 2. Fig. 2 is a flowchart showing an example of a process
10 which is car ried out by each uni t of the data t ransmission apparatus 10.
[0023] Fi rst ly, the calculat ion uni t 13 calculates the size of the
residual data generated by dividing the t ransmission data, which are
output ted by the transmission data generat ion apparatus 1, into the blocks
each having the predetermined data size (Step S1) .
15 [0024] Next , the residual data judgment uni t 14 judges whether the
size of the residual data calculated by the calculat ion uni t 13 is smal ler or
not smal ler than the minimum data size which the receiving apparatus 2
can receive (Step S2).
[0025] In the case that the residual data judgment uni t 14 judges
20 that the size of the residual data is smal ler than the minimum data size
(Yes in Step S2), the transmission data division uni t 11 divides the
transmission data so as to make a block, which includes the residual data,
include a part of the transmission data other than the residual data. As a
resul t , the residual data judgment 14 generates a block which includes the
25 residual data and whose data size is equal to or larger than the minimum
data size (Step S3) .
[0026] At this point of t ime, the transmission data division uni t 11
car ries out the data division so that a block other than the block, which
includes the residual data, may have a size equal to or larger than the
10
minimum data size.
[0027] The t ransmission uni t 12 transmi ts the t ransmission data
divided by the t ransmission data division uni t 11 into blocks, to the
receiving apparatus 2 (Step S4). Since each of the blocks generated by the
transmission data division uni t 11 has a size equal to or larger than th5 e
minimum data size, the receiving apparatus 2 can receive al l of the blocks
wi th no error .
[0028] In Step S2, in the case that the residual data judgment uni t
14 judges that the size of the residual data is larger than the minimum data
10 size (No in Step S2) , the t ransmission data division uni t 11 divides the
transmission data as fol lows. The t ransmission data division uni t 11
divides the t ransmission data into a block which includes the res idual data
and no other data (in Fig. 2, described as 'include only residual data') , and
one or more blocks each having a size which is equal to or smal ler than the
15 predetermined data size and is equal to or larger than the minimum data
size (Step S5) .
[0029] The t ransmission uni t 12 transmi ts the t ransmission data
divided by the t ransmission data division uni t 11 into blocks, to the
receiving apparatus 2 (Step S4). The block, which is generated in Step S5
20 and includes the residual data, has a size equal to or larger than the
minimum data size. Accordingly, since each of the blocks generated by the
transmission data division uni t 11 has a size equal t o or larger than the
minimum data size, the receiving apparatus 2 can receive al l of the blocks
wi th no error .
25 [0030] By carrying out the above -ment ioned process, even in the
case that the size of the residual data is smal ler than the minimum data
size, the data t ransmiss ion apparatus 10 can transmi t the transmission data
by dividing the t ransmission data into blocks each of whose sizes is equal
to or larger than the minimum data size. In other words, even i f the size of
11
the t ransmission data has any valu e, the data transmiss ion apparatus 10 can
transmi t the t ransmission data by diving the transmission data into the
blocks each of which has a size equal to or larger than the minimum data
size. Therefore, the transmission data division uni t 11 can avoid ca r rying
out a process of t ransmi t t ing a block to which excessive data (unused area5 )
other than the t ransmission data are added. Accordingly, i t is possible to
real ize ef ficient data transmission.
[0031] Here, the data t ransmission apparatus 10 may add
ident if icat ion informat ion, such as a header or the l ike, to the post -division
10 block. In this case, the receiving apparatus 2 restores the t ransmission data
from the received blocks on the basis of the ident i ficat ion informat ion.
[0032] The t ransmission data generat ion apparatus 1 and the data
transmission apparatus 10 may be const i tuted so as to be uni ted into one
apparatus.
15 [0033] Furthermore, the data t ransmission apparatus 10 may have a
configurat ion that the transmission uni t 12 is arranged external ly. In this
case, the data transmission apparatus 10 works as a data division apparatus
which divides the transmission data into blocks.
[0034] The invent ion which has been described in the above can be
20 regarded as an invent ion on a data division method for dividing the
transmission data. The data division method includes the fol lowing steps
(a), (b) and (c):
(a) calculat ing a size of residual data generated by dividing the
transmission data into blocks each of which has the predetermined data
25 size;
(b) judging whether the calculated size of the residual data is
smal ler or not smal ler than a minimum data size which a t ransmission
dest inat ion apparatus can receive; and
(c) generat ing a block, which includes the residual data and whose
12
data size is equal to or larger than the minimum data size, by dividing the
transmission data so as to make the block, which includes the residual data,
include a part of the transmission data other than the residual data, in the
case that i t is judged that the size of the resi dual data is smal ler than the
minimum data size5 .
A chip which car ries out the method may be mounted on the
transmission data apparatus 10.
[0035] Exemplary embodiment 2
Hereinaf ter, an exemplary embodiment 2 of the present invent ion
10 wi l l be explained wi th reference to drawings. Here, a part which has
already been explained in the exemplary embodiment 1 is pr operly omi t ted.
[0036] Fig. 3 shows one example of a wi reless communicat ion
system which includes L2SW (Layer 2 swi tch) app aratuses 3 and 4, and
wireless packet t ransmission apparatuses 20 and 30. In Fig. 3, the L2SW
15 apparatus 3 and the wireless packet t ransmission apparatus 20 are
connected each other via a LAN circui t s10, and the L2SW apparatus 4 and
the wi reless packet t ransmission apparatus 3 0 are connected each other via
a LAN circui t s20.
[0037] The L2SW apparatus 3 is a communicat ion apparatus
20 fol lowed by the wireless packet t ransmission apparatus 20, and outputs
packet data, which are cor responding to the transmission data, to the
wireless packet t ransmission apparatus 20 via the LAN ci rcui t s10. The
L2SW apparatus 4 is a communicat ion apparatus preceded by the wi reless
packet t ransmission apparatus 30, and obtains packet data, which are
25 corresponding to the transmission data, f rom the wi reless packet
transmission apparatus 30 via the LAN ci rcui t s20. The L2SW apparatus
3 is an apparatus opposi te to the wi reless packet t ransmission apparatus,
and the L2SW apparatus 4 is an apparatus opposi te to the wi reless packet
transmission apparatus 30.
13
[0038] Here, t ransmission capaci ty of the LAN ci rcui t s10 is larger
than t ransmission capaci ty of a wireless circui t r10, and is larger than
transmission capaci ty of a wireless circui t r20. However , a total of the
transmission capaci ty of the wi reless ci rcui t r10 and the t ransmission
capaci ty of the wi reless ci rcui t r20 is larger than the t ransmission capaci 5 ty
of the LAN circui t s10. Moreover, transmission capaci ty of the LAN circui t
s 20 is larger than the t ransmission capaci ty of the wi reless ci rcui t r 10,
and is larger than the transmission capaci ty of the wi reless ci rcui t r20.
However, a total of the transmission capaci ty of the wi reless circui t r10
10 and the t ransmission capaci ty of the wireless ci rcui t r20 is larger than the
transmission capaci ty of the LAN ci rcui t s10. The wi reless communicat ion
system shown in Fig. 3 t ransfers the packet data by use of both of the
wireless circui t r10 and the wi reless ci rcui t r20 (by binding the wireless
circui t r10 and the wireless ci rcui t r20) . As ment ioned above , the wireless
15 packet t ransmission apparatus 20 intends to increase the t ransmission
capaci ty by use of a plural i ty of ci rcui ts.
[0039] The wi reless packet t ransmission apparatus 20 and the
wireless packet transmission apparatus 30 are connected each othe r via the
wireless circui t r10 and the wi reless ci rcui t r20. The wi reless packet
20 transmission apparatus 20 t ransfers the packet data to the wi reless packet
transmission apparatus 30 via the wireless ci rcui ts r10 and r20 by use of
radio waves. That is, the wi reless packet t ransmission apparatus 20 and the
wireless packet t ransmission apparatus 30 are opposi te each other via the
wireless ci rcui ts.
25 [0040] The wi reless packet t ransmission apparatus 20 is a
transmission apparatus which is corresponding to the d ata t ransmission
apparatus 10 shown in Fig. 1. It is i l lustrated that the wi reless packet
transmission apparatus 20 includes a t ransmission packet data buffer
circui t ( t ransmission buffer circui t) 21, a packet data division circui t
14
(division circui t) 22, and a wireless sending circui ts (sending circui ts) 23
and 24. It is i l lust rated that the wi reless packet t ransmission apparatus 30
is a receiving apparatus which is corresponding to the receiving apparatus
2 shown in Fig. 1. Fig. 3 shows that the wireless p acket transmission
apparatus 30 includes wi reless receiving circui ts ( receiv ed ci rcui ts) 31 an5 d
32, received block data buf fer ci rcui ts (receiving buf fer ci rcui ts) 33 and
34, and a packet data restorat ion circui t 35 . Here, the wireless packet
transmission apparatus 30 is set so as not to receive a block which has a
size smal ler than a minimum block size (minimum data size) . Hereinaf ter,
10 each uni t of the wi reless packet t ransmission apparatuses 20 and 30 wi l l be
explained.
[0041] The t ransmission packet data buf fer circui t 21 car ries out a
buf fering process to a t ransmission packet signal p10 which the L2SW
apparatus 3 outputs, and outputs the buffered t ransmission packet signal
15 p10 to the packet data division ci rcui t 22 as a packet data signal
(transmission packet data signal p11) . The t ransmission packet data
buf fer ci rcui t 21 detects a size of the packet data which the L2SW
apparatus 3 outputs in the buffer ing process.
[0042] The packet data division ci rcui t 22 divides the packet data,
20 which the t ransmission packet data buffer ci rcui t 21 outputs, into a
plural i ty of blocks. Then, the packet data division ci rcui t 22 outputs a part
of the generated plural blocks to the wireless sending ci rcui t 23 as a
transmission division block signal p12, and outputs the left blocks to the
wireless sending ci rcui t 24 as a t ransmission division block signal p13.
25 [0043] Fig. 4 is a block diagram showing a configurat ion example
of the packet data division circui t 22. The packet data division circui t 22
includes a packet data division uni t 221, a calculat ion uni t 222 and a
residual data judgment uni t 223. The packet data division uni t 221, the
calculat ion uni t 222 and the residual data judgment uni t 223 are
15
corresponding to the transmission data division uni t 11, the calcula t ion
uni t 13 and the residual data judgment uni t 14 shown in Fig. 1 ,
respect ively. Detai ls of the packet data division process, which the packet
data division ci rcui t 22 car ries out , wi l l be described later.
[0044] Here, the packet data division ci rcui t 2 2 includes a memor5 y
(not shown in the drawings) which stores a fixed block size and the
minimum block size which are set by a user , and the size of the packet
data, input ted to the transmission packet data buffer circui t 21. The f ixed
block size is corresponding to the predetermined data size which is
10 described in the exemplary embodiment 1. The packet data division circui t
22 reads data, which is stored in the memory, according to a process
car ried out by each uni t , and uses the data.
[0045] The packet data division ci rcui t 22 assigns informat ion on a
head, an end and a sequence number of the block to each of the plural
15 blocks, into which the packet data division uni t 221 divides the packet
data, as a header . By the above, i t is possible for the packet dat a division
circui t 22 to make the packet data restorat ion ci rcui t 35, which is included
in the receiving side wireless packet t ransmission apparatus 30, restore the
packet data.
20 [0046] The wi reless sending circui t 23 mul t iplexes the block, which
the packet data division ci rcui t 22 outputs, into a wi reless frame, and
car ries out a wi reless sending process such as a modulat ion process, DA
(Digi tal to Analog) conversion, frequency conversion and the l ike. Then,
the wi reless sending circui t 23 sends data, whi ch are generated by the
25 wireless sending process, to the wireless packet t ransmission apparatus 30
via the wireless circui t r10 as a t ransmission wi reless signal p14.
Simi larly, the wi reless sending ci rcui t 24 car ries out a process such as the
wireless t ransmission process or the l ike to the block which the packet data
division ci rcui t 22 outputs. Then, the wireless sending ci rcui t 24 sends
16
data, which are generated by the wi reless transmission process, to the
wireless packet t ransmission apparatus 30 via the wi reless ci rcui t r20 as a
transmission wireless signal p15. The wi reless sending ci rcui ts 23 and 24
are cor responding to the transmission uni t 12 shown in Fig. 1.
[0047] The wi reless receiving ci rcui t 31 car ries out a wi reles5 s
receiving process such as f requency conversion, AD (Analog to Digi tal)
conversion, a demodulat ion process and the l ike to a receiv ed wireless
signal p25 (ident ical to sending wireless signal p14), which the wireless
receiving ci rcui t 31 receives via the wireless ci rcui t r10, and consequent ly
10 extracts the block f rom the wi reless frame. The wi reless receiving ci rcui t
31 outputs the ext racted block to the received block data buf fer circui t 33
as a received wireless block signal p23. Simi larly, the wi reless receiving
circui t 32 car ries out the wireless receiving process to a received wi reless
signal p26 (ident ical to t ransmission wireless signal p15), which the
15 wireless receiving ci rcui t 32 receives via the wi reless ci rcui t r20, and
consequent ly ext racts the block f rom the wireless f rame. Then, the
wireless receiving ci rcui t 32 outputs the extracted block to the receiv ed
block data buffer ci rcui t 34 as a received wi reless block signal p24.
[0048] The receiving block data buf fer ci rcui t 33 carries out a
20 buf fering process to the block which is received f rom the wireless
receiving ci rcui t 31, and afterward outputs the buf fered block to the packet
data restorat ion circui t 35 as a received division block signal p21.
Simi larly, the received block data buf fer circui t 34 car ries out a buffering
process to the block which is received f rom the wireless receiving ci rcui t
25 32, and af terward outputs the buf fered block to the packet data restorat ion
circui t 35 as a received division block signal p22.
[0049] The packet data restorat ion circui t 35 resto res the packet
data, which the received block data buffer circui t 33 and the received block
data buf fer circui t 34 output , to the original packet data which the wireless
17
packet t ransmission apparatus 20 obtains from the L2SW apparatus 3.
[0050] Specif ical ly, the packet data restorat ion ci rcui t 35 refers to
the header which the packet data division ci rcui t 22 of the wi reless packet
transmission apparatus 20 assigns to the packet data. The packet data
restorat ion circui t 35 judges a head posi t ion and an end posi t ion of th5 e
post -division block out of the data on the basis of the refer red header . As
ment ioned above, the packet data restorat ion ci rcui t 35 detects the
post -division block.
[0051] Furthermore, by refer ring to the sequence number which is
10 embedded in the header, the packet data restorat ion ci rcui t 35 judges
whether loss or disappearance of block is caused due to a faul t of the
wireless ci rcui t or the l ike or not . In the case that loss of sequence number
(state that discont inui ty of sequence number is caused) is not caused, the
packet data restorat ion circui t 35 restores the blocks to the or iginal packet
15 data by al igning the blocks in an order of the cont inuous sequence number.
[0052] In the case that loss of sequence number is caused, the
packet data restorat ion ci rcui t 35 discards a block which is being received,
and packet data which are in a restorat ion process. The packet data
restorat ion circui t 35 resumes the packet data restorat ion process f rom a
20 top block which is received next .
[0053] The packet data restorat ion circui t 35 outputs the packet
data, which are re-generated by the restorat ion process, to the L2SW
apparatus 4 as a received packet signal p20.
[0054] Here, for making explanat ion simpl ified, Fig. 3 shows only a
25 packet data sending side circui t ( t ransmission packet data buf fer ci rcui t 21,
packet data division circui t 22 and wireless sending ci rcui ts 23 and 24) in
the wi reless packet transmission apparatus 20. Simi lar ly, Fig. 3 shows only
a packet data receiving side circui t (wi rele ss receiving circui ts 31 and 32,
receiving block data buf fer ci rcui ts 33 and 34 and packet data restorat ion
18
circui t 35) in the wireless packet transmission apparatus 30. Actual ly, the
wireless packet t ransmission apparatus 20 and the wi reless packet
transmission apparatus 30 have the same configurat ion. That is, the
wireless packet t ransmission apparatus 20 includes the packet data
received side ci rcui t not shown, and the wireless packet transmissio5 n
apparatus 30 includes the packet data sending side ci rcui t not shown.
[0055] Fig. 5 is a block diagram showing a detai led configurat ion
example of the wi reless packet t ransmission apparatus 20. The wi reless
packet t ransmission apparatus 20 includes wi reless receiving circui ts 25
10 and 26, received block data buf fer ci rcui ts 27 and 28 and a packet data
restorat ion circui t 29 in addi t ion to the t ransmission packet data buf fer
circui t 21, the packet data division circui t 22 and the wi reless sending
circui ts 23 and 24 which are shown in Fig. 3. The wireless receiving
circui ts 25 and 26, the received block data buf fer ci rcui ts 27 and 28 and the
15 packet data restorat ion circui t 29 have the same ci rcui t configurat ions and
car ry out the same processes as the wi reless receiving ci rcui ts 31 and 32,
the received block data buf fer ci rcui ts 33 and 34 and the packet data
restorat ion circui t 35, respect ively. Here, the wireless receiving circui ts 25
and 26 receive data f rom the wireless packet t ransmission apparatus 30 via
20 wireless circui ts r30 and r40, respect ively. In the case of the wireless
packet t ransmission apparatus 30, the above -ment ioned packet data
sending side ci rcui t divides the packet data into the blocks, and sends the
block to the wi reless packet transmission apparatus 20 via the wireless
circui ts r30 and r40. Each uni t of the wi reless transmission apparatuses 20
25 and 30 ment ioned above is real ized by hardware such as IC ( Integrated
Circui t ) or the l ike, software such as appl icat ion software or the l ike or the
hardware and the sof tware.
[0056] Fig. 6 is a flowchart showing an example of a packet data
division process method which the packet data division circui t 22 car ries
19
out . Hereinafter , the packet data division process which the packet data
division ci rcui t 22 car ries out wi l l be explained wi th reference to Fig. 6.
Here, the packet data division ci rcui t 22 car ries out the packet data
division process on the basis of the fixed block size and the minimum
block size which are set in advance. In the fol lowing process, each uni t o5 f
the packet data division ci rcui t 22 reads data on the f ixed block size, the
minimum block size and the size of the packet data, which are stored in a
memory, according to necessi ty.
[0057] Fi rst ly, the calculat ion uni t 222 of the packet data division
10 circui t 22 judges whether a size X of the packet data, which are input ted
from the transmission packet data buffer circui t 21, is an integral mul t iple
(n mul t iple) of a fixed block size M or not (Step S11). In other words, the
calculat ion uni t 222 calculates a size x of the residual data which a re
generated by dividing the packet data into the blocks each having the fixed
15 block size M, and judges whether x is 0 or not .
[0058] In the case that the calculat ion uni t 222 judges that the size
X of the packet data is n t imes as large as the fixed block size M, that is, in
the case that the calculat ion uni t 222 judges that the size x of the residual
data is 0 (Yes in Step S11), the packet data division uni t 222 divides the
20 packet data into n blocks (Step S12) . Each of the n blocks has the same
fixed block size M.
[0059] The packet data division ci rcui t 22 assigns informat ion on a
head, an end, a sequence number or the l ike of the block to each block as a
header . Then, by dist ribut ing and output t ing the blocks to the wireless
25 sending circui ts 23 and 24, the packet data division ci rcui t 22 distr ibutes
and sends the packet data to the plural wi reless ci rcui ts (wireless ci rcui ts
r10 and r20) .
[0060] In the case that i t is judged that the size X of the packet data
is not an integral mul t iple of the fixed bl ock size M, that is, in the case that
20
i t is judged that the size x of the residual data is not 0 (No in Step S11), the
residual data judgment uni t 223 judges whether the size x of the residual
data is equal to or larger than the minimum block size m or not (Step S14)
[0061] In the case that the residual data judgment uni t 223 judges
that the size x of the residual data is equal to or larger than the minimu5 m
block size m (Yes in Step S14), the packet data division uni t 221 divides
the packet data into one or more blocks each of which has the fixed block
size, and one block which includes only the residual data (Step S15) . Here,
since the size x of the residual data is equal to or larger than the minimum
10 block size m, the wireless packet t ransmission apparatu s 20 can receive the
residual data. Accordingly, the wi reless packet t ransmission apparatus 30
can t ransmi t al l of the blocks into which the data packet is divided. The
packet data division circui t 22 assigns a header to each block, and
distr ibutes and sends the blocks to the plural wi reless ci rcui ts (Step S13) .
15 [0062] In the case that the residual data judgment uni t 223 judges
that the size x of the residual data is smal ler than the minimum block size
m (Yes in Step S14) , the packet data division uni t 221 divides the packet
data as fol lows. The packet data division uni t 221 divides the packet data
into one or more blocks each of which has the fixed block size M, a block
20 which includes the residual data and a block whose size is equal to or
smal ler than the fixed block size M and is equal to or larger than the
minimum block size m. Here, the block, which includes the residual data,
includes a part of the packet data other than the residual data (Step S16).
As ment ioned above, the packet data division uni t 2 21 divides the packet
25 data so that the block, which includes the residual data, may have a size
equal to or larger than the minimum block size m.
[0063] Here, the par t of the packet data, which are included in the
block including the residual data and whi ch are di f ferent f rom the residual
data, are data which just fol low or just precede the residual data in a
21
sequence of the packet data. In other words, the par t of the data packet
other than the residual data are data which exist just before or just af ter the
residual data in the sequence of the packet data, that is, there is no data
between the residual data and the part of the packet data.
[0064] The packet data division ci rcui t 22 assigns a header to eac5 h
block which is generated in the process ment ione d above, and distr ibutes
and sends the blocks to the plural wi reless ci rcui ts (Step S1 3).
[0065] Each of Figs. 7A to 7C is an image diagram showing an
example of the packet data division method for dividing the packet data on
10 the basis of a procedure which is described in the flowchart shown in Fig.
6. Fig. 7A shows the packet data division method appl ied to a case that the
size X of the packet data, which are received f rom the L2SW apparatus 3,
is 1280 bytes. Simi larly, Fig. 7B shows the packet data divis ion method
appl ied to a case that the size X of the packet data, which are received from
15 the L2SW apparatus 3, is 1279 bytes, and Fig. 7C shows the packet data
division method appl ied to a case that the size X of the packet data, which
are received from the L2SW apparatus 3, is 1281 bytes. Here, in every
case, the fixed block size M is 256 bytes, and the minimum block size m is
64 bytes.
20 [0066] Fig. 7A indicates that the packet data of 1280 bytes are
divided into 5 blocks of 256 bytes. In Step S11 shown in Fig. 6, the
calculat ion uni t 222 judges whether the size X of the packet data is an
integral mul t iple of the f ixed block size M or not . Here, since the size X of
the packet data is 1280 bytes, and the fixed block size is 256 bytes, the size
25 of the packet data is just 5 t imes as large as the f ixed block size.
Accordingly, in Step S11 shown in Fig. 6, the packet data division ci rcui t
22 judges that the size X of the packet data is an integral mul t iple of the
fixed block size M (Yes in Step S11) .
[0067] The packet data division uni t 221 divides the packet data
22
into 5 blocks (Step S12) . Each of these 5 blocks has a block size of 256
bytes. Then, the packet data division ci rcui t 22 assigns informat ion on a
head, an end and a sequence number of the block to eac h block as a header
(header is denoted as 'H' in Figs. 7A to Fig. 7C). The packet data division
circui t 22 distributes and sends the 5 blocks, to each of which the header i5 s
assigned, to the wireless circui ts (Step S13).
[0068] Fig. 7B indicates that the packet data of 1279 bytes are
divided into 4 blocks of 256 bytes and one block of 255 bytes. The
calculat ion uni t 222 judges whether the size X of the packet data is an
10 integral mul t iple of the fixed block size M or not . In this case, since the
size of the data packet is 1279 bytes, and the f ixed block size is 256 bytes,
the size of the packet data is not an integral mul t iple of the fixed block
size. Accordingly, in Step S11 shown in Fig. 6, the calculat ion uni t 222
judges that the size X of the packet da ta is not an integral mul t iple of the
15 fixed block size M ( No in Step S11). At this point of t ime, the calculat ion
uni t 222 calculates the size x of the residual data, and f inds that the size x
is 255 bytes.
[0069] The residual data judgment uni t 223 judg es whether the size
x of the residual data, which are left when dividing the packet data by the
20 fixed block size M, is equal to or larger than the minimum block size m or
not (Step S14) . In Fig. 7B, since the size x of the residual data is 255 bytes,
and the minimum block size m is 64 bytes, the size x of the residual data is
larger than the minimum block size m. Accordingly, the residual data
judgment uni t 223 judges that the size x of the residual data is equal to or
25 larger than the minimum block size m (Yes in Step S14) , and divides the
packet data into 4 blocks and one block which includes only the residual
data (Step S15). Each of these 4 blocks has the same fixed block size M.
The packet data division ci rcui t 22 assigns a header to each block, and
dist r ibutes and sends the blocks, to each of which the header is assigned, to
23
the plural wireless ci rcui ts (Step S13).
[0070] Fig. 7C indicates that the packet data of 1281 bytes are
divided into 4 blocks of 256 bytes, one block of 128 bytes and one block of
129 bytes. In the flow shown in Fig. 6, the packet data division circui t 22
judges whether the size X of the packet data which are input ted f rom th5 e
transmission packet data buffer circui t 21 is an integral mul t iple of the
fixed block size M or not (Step S11) . In this case, since the size X of the
data packet is 1281 bytes, and the fixed block size M is 256 bytes, the size
X of the packet data is not an integral mul t iple of the fixed block size M.
10 Accordingly, in Step S11 shown in Fig. 6, the calculat ion u ni t 222 judges
that the size X of the packet data is not an integral mul t iple of the fixed
block size M (No in Step S11). At this point of t ime, the calculat ion uni t
222 calculates the size x of the residual data, and finds that the size x is 1
byte.
15 [0071] The residual data judgment uni t 223 judges whether the size
x of the residual data, which are left when dividing the packet data by the
fixed block size M, is equal to or larger than the minimum block size m or
not (Step S14) . In Fig. 7C, since the size x of the residual data is 1 byte,
and the minimum block size m is 64 bytes, the size x of the residual data is
20 smal ler than the minimum block size m. Accordingly, the residual data
judgment uni t 223 judges that the size x of the residual data is smal ler t han
the minimum block size m (No in Step S14)
[0072] The packet data division uni t 221 divides the packet data
into 4 blocks each of which has the fixed block size M, a block having a
25 size x1 which is equal to or smal ler than the fixed block size M and wh ich
is equal to or larger than the minimum block size m, and a block which
includes the residual data and which has a size x2 (Step S16). Here, the
size x1 is 128 bytes, and the size x2 is 129 bytes. This is because data,
which include the residual data of 1 byte and a par t of the packet data of
24
256 bytes ( fixed block size M), are divided into 2 blocks of almost the
same size. The packet data division circui t 22 assigns a header to each
block which is generated in the above -ment ioned process, and distr ibutes
and sends the generated blocks to the plural wi reless ci rcui ts (Step S13) .
[0073] Fig. 8A and Fig. 8B show detai ls of the division processe5 s
shown in Fig. 7B and Fig. 7C, respect ively. In Fig. 8A and Fig. 8B, a left
end of the packet data indicates a he ad of the packet data, and a right end
indicates an end of the packet data.
[0074] In Fig. 8A, the packet data division uni t 221 divides 1024
10 bytes from the head of the packet data into 4 blocks each of which has the
fixed block size M. Then, the packet data division uni t 221 generates one
block including only the residual data of 255 bytes in the tai l of the packet
data. The packet data division ci rcui t 22 assigns a header to each of the
generated blocks.
15 [0075] In Fig. 8B, the packet data division uni t 221 divides 1024
bytes from the head of the packet data into 4 blocks each of which has the
fixed block size M. Then, the packet data division uni t 221 divides the
residual data of 1 byte in the tai l , and data of second last end side 256
bytes into a block which has the size x1 of 128 bytes, and a block which
20 has the size x2 of 129 bytes. Here, the block which has the size of 129
bytes includes the residual data of 1 byte, and the data of 128 bytes which
are cor responding to the part of the packet data othe r than the residual
data. The data of 128 bytes, which are cor responding to the par t of the
packet data other than the residual data, are data which exist on the second
25 last end side of the packet data whi le the residual data exist on the last end
side ( that is, the data of 128 bytes exist just before the residual data.) .
Accordingly, there is no data between the residual data and the data of 128
bytes.
[0076] As ment ioned above, the packet data division ci rcui t 22
25
divides the packet data according to th e method which is based on the size
of the packet data, that is, which is di fferent dependent ly on the size of the
packet data.
[0077] Here, the packet data division ci rcui t 22 may carry out the
flow process shown in Fig. 6 together wi th dividing the pack et data. Fo5 r
example, in the case that the size of the packet data is 1281 bytes, the
packet data division uni t 221 divides block data from the head side of the
packet data into blocks each of which has the fixed block size of 256 bytes,
and assigns a header to each the block, and distributes the blocks to the
10 wireless circui ts. Simul taneously, the calculat ion uni t 222 calculates the
size x of the residual data on the basis that the size of the packet data is
1281 bytes, and finds that the size x of the res idual data is 1 byte. The
residual data judgment uni t 223 judges that the size x of the residual data is
smal ler than the minimum block size m, and divides the residual data of 1
15 byte in the tai l and the data of the second end side 256 bytes out of the
packet data into the block which has the size of 128 bytes and the block
which has the size of 129 bytes. Then, the packet data division ci rcui t 22
assigns a header to each division block, and distr ibutes the blocks to the
wireless circui ts.
20 [0078] Or, the packet data division circui t 22 may divide al l of the
packet data into the blocks, and afterward dist ribute and send the blocks to
the wi reless ci rcui ts 23 and 24. Here, by car rying out the f low process
shown in Fig. 6 together wi th dividing the packet data , i t is possible to
send the packet data to the wi reless packet transmission apparatus 30 in a
25 short t ime.
[0079] Each of Fig. 9A and Fig. 9B is an image diagram showing a
packet data division method according to a related art . Fig. 9A shows the
packet data division method which is appl ied to a case that the packet data,
which are received f rom the L2SW apparatus 3, have a size of 1280 bytes,
26
and Fig. 9B shows the packet data division method which is appl ied to a
case that the packet data, which are receiv ed f rom the L2SW apparatus 3,
has a size of 1281 bytes . Here, in Fig. 9A and Fig. 9B, a header (denoted as
'H') is assigned to a block.
[0080] Fig. 9A indicates that packet data of 1280 bytes are divide5 d
into 5 blocks of 256 bytes. In this case, since the size of the packet data
can be divided by the fixed block size M, a padding process is not carried
out . Accordingly, data which are in a used area do not exist in the block.
[0081] However, in the case that the size of the packet data cannot
10 be divided by the fixed block size, the unused area is caused in the block.
Fig. 9B indicates that the packet data of 1281 bytes are divided into 6
blocks of 256 bytes. The packet data are divided into the blocks each of
which has the fixed block size of 256 bytes, and the residual data which
has the size x of 1 byte. According to the method of the related art , one
15 block, which has the fixed block size of 256 bytes, is generated by adding
an unused area U of 255 bytes (by car rying out the padding process) to the
residual data of 1byte. Then, the packet t ransmission apparatus transmi ts
the generated 6 blocks. In this case, since the unused area is caused the
block, packet data t ransmission efficiency become s degraded.
20 [0082] In contrast , the padding process is not ca rr ied out in the
generat ion process shown in Fig. 7A to Fig. 7C. Therefore, i t is possible to
avoid t ransmission of useless data which are cor responding to the unused
area, and to real ize enhancement of data t ransmission ef ficiency.
[0083] Furthermore, as shown in Fig. 7C, on the basis of the data of
25 256 bytes (corresponding to one block which has the fixed block size M)
and the residual data, the packet data division ci rcui t 22 generates the
block which includes the residual data, and the block whose data size is
equal to or smal ler than the fixed block size M and is equal to or larger
than the minimum block size m. The packet data division circui t 22
27
generates 4 blocks each of which has the fixed block size M in addi t ion to
the generated blocks ment ioned above. As ment ioned above, by generat ing
the block, which includes the residual data, on the basis of only the
residual data and the data cor responding to one block which has the fixed
block size M, the packet data division circui t 22 can generate one bloc 5 k,
whose size is equal to or larger than the minimum block size m and which
includes the residual data, in smal l number of processes. Moreover,
according to the method, i t is possible to car ry out the process of
generat ing the block, which includes the res idual data, together wi th
10 dividing the packet data from the head side of the packet data into the
blocks and dist ribut ing the blocks to the wireless circui ts, as ment ioned
above. Speci fical ly, in Fig, 7C, by dividing the packet data, the
transmission data division uni t 221 generates the block, which has the size
of 256 bytes, before generat ing the block of 129 bytes which includes the
15 residual data, and the block which has the data size of 128 bytes. Then, the
sending circui ts 23 and 24 t ransmi t the blocks, which the t ransmission data
division uni t 221 generates, in turn. Therefore, an effect that i t is possible
to start t ransmission early in comparison wi th a case of start ing
transmission after division into the blocks is completed.
20 [0084] Here, the packet data division uni t 221 divides a total of the
residual data of one byte, and the part of the packet data of 256 bytes
(fixed block size M) into two blocks of almost the equal data size. Here,
'almost equal ' includes a case that a size of one block is di f f erent f rom a
size of another block by one byte to several bytes. In other words,
25 'almost equal ' includes a case that there is a di fference between sizes of
two blocks, which are generated by division, to such an extent that
transmission t imes of the two blocks f rom the wi reless packet transmission
apparatus 20 to the wireless packet t ransmission apparatus 30 are regarded
to be equal each other . By vi rtue of the above, i t is possible to make the
28
transmission t imes of the two blocks, which are generated by d ivision,
from the wi reless packet t ransmission apparatus 20 to the wi reless packe t
transmission apparatus 30 almost equal . Therefore, i t is possible to make
the packet data restorat ion ci rcui t 35 of the receiving side wi reless packet
transmission apparatus 30 car ry out the restorat ion process early an5 d
accurately in compar ison wi th a case that there is the dif ference between
the transmission t imes of the two blocks from the wi reless packet
transmission apparatus 20 to the wi reless packet transmission appara tus
30.
10 [0085] In Fig. 7C, the part of the packet data, which are included in
the block including the residual data and which are di f ferent f rom the
residual data, are data which just fol low or just precede the residual data.
Here, even i f the par t of the packet data are not data which just fol low or
just precede the residual data, i t is possible to real ize enhancement of data
15 transmission ef ficiency. However, in the case that the part of the packet
data are data which just fol low or just precede the re sidual data, a t ime
requi red for the packet data restorat ion process, which is carried out by the
packet data restorat ion circui t 35 of the wireless packet t ransmission
apparatus 30, becomes short , and consequent ly i t is possible to carry out
20 the restorat ion process ef ficient ly.
[0086] Here, whi le i t has been explained in Fig. 7C that the fixed
block size M is 256 bytes, and the minimum block size m is 64 bytes, other
values may be appl icable. However , in order to generate two blocks, each
of whose sizes is equal to or larger than the minimum block size m, on the
25 basis of the residual data and the data whose size is the fixed block size, i t
is necessary that the fixed block size is 2 or more t imes as large as the
minimum block size.
[0087] In the case that the size of the residual data is equal to or
larger than the minimum block size as shown in Fig. 7B, the packet data
29
division ci rcui t 22 assigns a header to the residual data as i t is to t ransmi t
the residual data including the header. Therefore, i t is p ossible to reduce a
process t ime which the packet data division circui t 22 consumes.
[0088] In the case that there is no residual data (that is, size of
residual data is 0), the packet data division uni t 221 divides the packet dat5 a
into the blocks each of which has the fixed block size to t ransmi t the
blocks. Therefore, the packet data division ci rcui t 22 can t ransmi t the
packet data ef ficient ly.
[0089] Exemplary embodiment 3
10 Hereinaf ter, an exemplary embodiment 3 of the present invent ion
wi l l be explained wi th reference to drawings. The exemplary
embodiment 3 shows another appl icat ion example of the data t ransmission
apparatus according to the present invent ion. Here, par ts which have
already been explained in the exemplary embodiments 1 and 2 are properly
15 omi t ted.
[0090] Fig. 10 shows a wi reless communicat ion system which
includes the L2SW apparatuses 3 and 4 and wireless packet t ransmission
apparatuses 40, 50, 60 and 70. In Fig. 10, the L2SW apparatus 3 and the
wireless packet t ransmission apparatus 40 are connected each other via the
20 LAN circui t s10, and the L2SW apparatus 4 and the wi reless packet
transmission apparatus 60 are connected each other via the LAN circui t s20.
The wi reless packet t ransmission apparatus 40 and the wireless packet
transmission apparatus 60 are connected each other via the wi reless ci rcui t
r10 and the wireless circui t r30. The wireless packet t ransmission
25 apparatus 50 and the wi reless packet t ransmission apparatus 60 are
connected each other via the wireless circui t r20 and the wi reless ci rcui t
r40. The wi reless ci rcui ts r10 to r40 are the same as the wi reless ci rcui ts
r10 to r40 shown in Fig.5, respect ively.
[0091] The wi reless packet t ransmission apparatus 40 includes a
30
sending and receiving cont rol ci rcui t 41, a wireless sending ci rcui t 42 and
a wi reless receiving circui t 43. The wi reless packet t ransmission apparatus
50 includes a t ransmission and received data buf fer ci rcui t 51, a wi reless
sending circui t 52 and a wi reless receiving circui t 53. The wireless packet
transmission apparatus 60 includes a wi reless receiving ci rcui t 61, 5 a
wireless sending ci rcui t 62 and a sending and receiving control ci rcui t 63.
The wi reless packet t ransmission apparatus 70 includes a wireless
receiving ci rcui t 71, a wireless sending ci rcui t 72 and a t ransmission and
received data buf fer circui t 73.
10 [0092] Detai ls of configurat ions of the wireless packet transmission
apparatus 40 and the wi reless packet t ransmission apparatus 50 wi l l be
explained in the fol lowing wi th reference to Fig. 11. Fi g. 11 is a block
diagram showing an example of configurat ions of the wi reless packet
transmission apparatus 40 and the wi reless packet t ransmission apparatus
15 50.
[0093] The sending and receiving cont rol circui t 41 of the wireless
packet t ransmission apparatus 40 includes a transmission packet data
buf fer ci rcui t 44, a packet data division circui t 45, a receiv ed block data
buf fer ci rcui t 46 and a packet data restorat ion circui t 47. The transmission
20 packet data buffer ci rcui t 44, the packet data division ci r cui t 45, the
received block data buf fer ci rcui t 46 and the packet data restorat ion ci rcui t
47 have the same ci rcui t configurat ions and car ry out the same processes as
the transmission packet data buf fer ci rcui t 21, the packet data division
circui t 22, the received block data buf fer circui t 27 and the packet data
25 restorat ion circui t 29 in Fig. 5, respect ively. The wireless sending ci rcui t
42 and the wi reless receiving circui t 43 have the same circui t
configurat ions and car ry out the same processes as the wi r eless sending
circui t 23 and the wi reless receiving ci rcui t 25 in Fig. 5, respect ively.
[0094] The wi reless packet t ransmission apparatus 40 has a
31
configurat ion in which the wireless sending circui t 24, the wireless
receiving ci rcui t 26 and the received block data buf fer ci rcui t 28 are
deleted f rom the wi reless packet t ransmission apparatus 20 shown in Fig. 5.
A t ransmission division block signal p30, which is output ted f rom the
packet data division circui t 45, is input ted into the wi reless packe5 t
transmi ssion apparatus 50, and a receiving division block signal p40,
which is input ted into the packet data restorat ion ci rcui t 47, is output ted
from the wi reless packet t ransmission apparatus 50 .
[0095] The t ransmission and received data buf fer circui t 51 of the
10 wireless packet t ransmission apparatus 50 includes a transmission packet
data buffer circui t 54 and a received block data buf fer ci rcui t 55. The
wireless sending ci rcui t 52, the wi reless receiving circui t 53, the
transmission packet data buffer circui t 54 and the received block data
buf fer ci rcui t 55, which are instal led in the wi reless packet transmission
15 apparatus 50, have the same ci rcui t configurat ions and car ry out the same
processes as the wi reless sending ci rcui t 24, the wireless receiving ci rcui t
26, the t ransmission packet data buffer ci rcui t 21 and the received block
data buffer circui t 28 in Fig. 5, respect ively.
[0096] Here, an operat ion of the wi reless packet t ransmission
20 apparatus 50 wi l l be explained. The transmission packet data buf fer ci rcui t
54 carries out a buffering process to the t ransmission division block signal
p30 which is input ted f rom the wi reless packet t ransmission apparatus 40,
and outputs the buffered t ransmission division block signal p30 to the
wireless sending ci rcui t 52 as a t ransmission division block signal p31.
25 [0097] Here, the t ransmission division block signal p30, which is
input ted f rom the wi reless packet t ransmission apparatus 40, is the same as
the t ransmission division block signal p13 which is generated by th e packet
data division ci rcui t 22 of the wireless packet t ransmission apparatus 20
shown in Fig. 5.
32
[0098] The wi reless sending circui t 52 carries out a wireless
sending process, such as a process of mul t iplexing to a wi reless f rame, a
modulat ion process, DA conversion, f requency conversion and the l ike, to
the transmission division block signal p31 which is input ted f rom the
transmission packet data buffer circui t 54. Afterward, the t ransmissio5 n
division block signal p31 is sent to the wi reless ci rcui t r2 0 as a
transmission wireless signal p32.
[0099] The wi reless receiving circui t 53 carr ies out a wireless
receiving process, such as f requency conversion, AD conversion, a
10 demodulat ion process and the l ike, to a receiv ed wireless signal p42 which
is input ted f rom the wireless circui t r40. Afterward, the received wi reless
signal p42 is output ted to the received block data buf fer ci rcui t 55 as a
received wi reless block signal p41.
[0100] The received block data buffer ci rcui t 55 carries out a
15 buf fering process to the received wireless block signal p41 which is
input ted f rom the wi reless receiving ci rcui t 53, and outputs the buffered
received wi reless block signal p41 to the packet data restorat ion circui t 47
as the received division block signal p40.
[0101] Here, the received division block signal p40, which is
20 output ted to the wi reless packet t ransmission apparatus 40, is the same as
the received division block signal p22 which is received by the packet data
restorat ion circui t 29 of the wireless packet t r ansmission apparatus 20
shown in Fig. 5.
[0102] Here, the wi reless receiving circui t 61, the wi reless sending
25 circui t 62 and the sending and receiving control circui t 63 of the wi reless
packet t ransmission apparatus 60 have the same ci rcui t configurat ions and
car ry out the same processes as the wi reless receiving ci rcui t 43, the
wireless sending ci rcui t 42 and the sending and receiving cont rol circui t
41 , respect ively. The wireless receiving circui t 71, the wireless sending
33
circui t 72 and the t ransmission and received data buffer ci rcui t 73 have the
same ci rcui t configurat ions and carry out the same processes as the
wireless receiving ci rcui t 53, the wireless sending ci rcui t 52 and the
transmission and received data buffer ci rcui t 51, respect ively. Each uni t of
the wi reless packet t ransmission apparatuses 50 and 60 is real ized b5 y
hardware such as IC ( Integrated Circui t ) or the l ike, software such as
appl icat ion software or the l ike or the hardware and the software.
[0103] By the above, the wireless communicat ion system, which
car ries out the wi reless communicat ion by use of plural wi reless packet
10 transmission apparatuses, has been explained. Since also the wireless
communicat ion system can carry out the process which is the same as the
process in the exemplary embodiment 2, i t is possible to real ize
enhancement of data transmission ef ficiency.
[0104] Exemplary embodiment 4
15 Hereinaf ter, an exemplary embodiment 4 of the present invent ion
wi l l be explained wi th reference to a drawing. The exemplary embodimen t
4 shows another appl icat ion example of the data t ransmission apparatus
according to the present invent ion. Here, parts which have al ready been
explained in the exemplary embodiments 1 to 3 are properly omi t ted.
20 [0105] Fig. 12 shows a communicat ion system which includes the
L2SW apparatuses 3 and 4, and packet t ransmission apparatuses 80 and 90.
In Fig. 12, the L2SW apparatus 3 and the packet t ransmission apparatus 80
are connected each other via the LAN circui t s10, and the L2SW apparatus
4 and the packet t ransmission apparatus 90 are connected each other via the
25 LAN circui t s20.
[0106] The packet t ransmission apparatus 80 includes a
transmission packet data buffer ci rcui t 81 and a packet data division ci rcui t
82, and the packet t ransmission apparatus 9 0 includes a received block data
buf fer ci rcui ts 91 and 92, and a packet data restorat ion circui t 93.
34
[0107] The packet t ransmission apparatus 80 is a packet
transmission apparatus in which the wi reless sending circui ts 23 and 24 are
deleted f rom the wi reless packet t ransmission apparatus 20 shown in Fig. 3.
The packet t ransmission apparatus 90 is a packet transmission apparatus
which has a configurat ion obtained by delet ing the wi reless receivin5 g
circui ts 31 and 32 from the wi reless packet t ransmission ap paratus 30
shown in Fig. 3.
[0108] The t ransmission packet data buf fer circui t 81 and the
packet data division circui t 82 have the same circui t configurat ions and
10 car ry out the same processes as the transmission packet data buf fer ci rcui t
21 and the packet data division ci rcui t 22 in Fig. 3, respect ively. The
packet data division circui t 82 outputs a t ransmission division block signal
p50 and a t ransmission division block signal p51 which are generated by
dividing transmission data into blocks. The transmission division block
15 signal p50 is output ted to the packet t ransmission apparatus 90 via a LAN
circui t s30, and the t ransmission division block signal p51 is output ted to
the packet t ransmission apparatus 90 via a LAN ci rcui t s40.
[0109] The received block data buffer ci rcui ts 91 and 92 have the
same ci rcui t configurat ions as the received block data buf fer circui ts 33
20 and 34 in Fig. 3, respect ively. The received block data buf fer circui t 91
car ries out a buffering process to a received transmission division block
signal p60 ( the same signal as t ransmission division block signal p50) , and
afterward outputs the buf fered t ransmission division block signal p60 to
the packet data restorat ion ci rcui t 93 as the received division block signal
25 p21. The received block data buf fer circui t 92 carr ies out the same process.
The packet data restorat ion circui t 93 has the same ci rcui t configurat ion
and car ries out the same process as the packet data restorat ion circui t 35 in
Fig. 33, respect ively.
[0110] Here, for making explanat ion simpl ified, Fig. 12 shows only
35
a packet data sending side ci rcui t ( t ransmission packet data buf fer ci rcui t
81 and packet data division circui t 82) in the case of the packet
transmission apparatus 80, and only a packet data receiving side ci rcui t
(received block data buf fer ci rcui ts 91 and 92, and packet data restorat ion
circui t 93) in the case of the packet t ransmission apparatus 90. Actual ly5 ,
the packet t ransmission apparatus 80 and the packet transmission apparatus
90 have the same configurat ion. That is, the packet t ransmission apparatus
80 includes furthermore the packet data receiving side ci rcui t not shown in
the figure, and the packet t ransmission apparatus 90 includes the packet
10 data sending side ci rcui t not shown in the figure. The recei ving side ci rcui t
and the sending side circui t have the same configurat ions as ones shown in
Fig. 12. Each uni t of the packet t ransmission apparatuses 80 and 90 is
real ized by hardware such as IC ( Integrated Circui t ) or the l ike, software
such as appl icat ion software or the l ike or the hardware and the software.
15 [0111] By the above, the communicat ion system, which car ries out
the wi reless communicat ion by use of not the wi reless ci rcui t but the plural
LAN circui ts, has been explained. Since also the wi rel ess communicat ion
system can car ry out the same process as the process in the exemplary
embodiments 2 and 3, i t is possible to real ize enhancement of data
20 transmission ef ficiency.
[0112] At present , while there are many communicat ion services
and an amount of network t raf fic becomes increasing, an art to make l ine
capaci ty increasing is required. The present invent ion is conceived to
real ize enhancement of data transmission ef ficiency on the basis of such
25 the background art . The present invent ion is appl ic able to a technical field
on data t ransmission. The present invent ion is appl i cable to, for example,
packet data t ransmission which includes wireless packet data transmission.
[0113] Here, the present invent ion is not l imi ted to the
above-ment ioned exemplary embodiment , and i t is possible to make
36
changes properly wi thin the scope of intent ion.
[0114] For example, in Fig. 7C of the exemplary embodiment 2, the
packet data division uni t 221 does not have to divide a total of the residual
data of 1 byte and the data of 256 bytes into 2 blocks which have the same
size. The packet data division uni t 221 can carry out another divisio5 n
method as far as a block, whose size is equal to or smal ler than the fixed
block size M and is equal to or larger than the minimum block size m, is
generated according to the method. For example, the packet data division
uni t 221 may divide a total of the residual data of 1 byte and the data of
10 256 bytes into a block of 64 bytes which includes the residual data of 1
byte, and a block of 193 byte (f irst data size) . Also by carr ying out the
above-ment ioned process, since many blocks each of which has the fixed
block size M are generated, a t ime required for the packet data division
22's carrying out the process is shortened in compariso n wi th a case of
15 generat ing many blocks each of which has a size di f ferent f rom the fixed
block size M. That is, i t is possible to car ry out the division process
ef ficient ly.
[0115] However, by the packet data division uni t 221's dividing
data, which include the residual data of 1 byte and the data of 256 bytes,
20 into 2 blocks which have the same data size, i t is possible to make
transmission t imes, which are requi red for t ransmi t t ing the 2 blocks to the
wireless packet t ransmission apparatus 30, the same e ach other .
Accordingly, f rom a point of view of t ransmission ef ficiency, i t is
desi rable that the packet data division circui t 221 d ivides data, which
25 includes the residual data, into 2 blocks which have the same data size.
[0116] In Fig. 7C, the block of 128 bytes and the block of 129 bytes,
which are generated by division, does not have to be t ransmi t ted at the
same t ime, that is, may be t ransmi t ted at t imes di fferent each other.
Furthermore, when car rying out the packet data division process, the
37
transmission data division uni t 221 may generate the block of 128 bytes
and the block of 129 bytes at fi rst . Or, the transmission data division uni t
221 may generate the block of 128 bytes first ly and generate the block of
129 bytes final ly. However, i t is des i rable that an order of data in the
packet data, which are transmi t ted f rom the wi reless packet transmissio5 n
apparatus 20 to the wireless packet t ransmission apparatus 30, is ident ical
wi th an order of data in the original packet data. The reason is to mak e the
packet data restorat ion process carried out faster and more accurately.
[0117] In Fig. 7C, the packet data division uni t 221 may divide the
10 packet data into one or more blocks each having a second data size which
is di fferent f rom the fixed block s ize M and is equal to or larger than the
minimum block size m, and one or more blocks each having a third data
size which is equal to or smal ler than the fixed block size M and is equal to
or larger than the minimum block size m. For example, in the case t hat the
15 size X of the packet data is 1816 bytes, the packet data division uni t 221
may divide the packet data so as to generate 7 blocks of 250 bytes di fferent
from the fixed block size M (256 bytes) , and one block of 66 bytes equal to
or smal ler than the fixed block size M and equal to or larger than the
minimum block size m. Here, i t is unnecessary that the blocks, each of
20 which has the second data size, have exact ly equal data size. The blocks,
each of which has the second data size, may have above -ment ioned 'almost
equal ' data size. For example, instead of generat ing 7 blocks of 250 bytes,
the packet data division uni t 221 may generate one block of 248 bytes, one
block of 252 bytes and 5 blocks of 250 bytes. The above is simi lar to the
25 third data size.
[0118] In the case that the size X of the packet data is 1816 bytes,
the packet data division uni t 221 can divide the packet data into 7 blocks
each of which has the fixed block size M, and one block of 24 bytes. Here,
since the block of 24 bytes has a si ze smal ler than the minimum block size
38
m, the wi reless packet t ransmission apparatus cannot t ransmi t the block of
24 bytes as i t is. Accordingly, the above -ment ioned division process can be
regarded as a process in which the packet data division uni t 221 a ssigns 6
bytes of each of 7 blocks, each of which has the fixed block size M , to the
block of 24 bytes to generate blocks each of whose sizes is equal to o5 r
larger than the minimum block size m.
[0119] Also by carrying out the above -ment ioned process, i t is
possible to reduce types of size of the blocks generated by dividing the
packet data. Therefore, in comparison wi th a case of dividing the packet
10 data so as to make the size of block randomized, i t is possible for the
packet data division circui t 22 to car ry out the division process more
ef ficient ly. Furthermore, each t ransmission t ime of blocks, each of which
has the same size, f rom the wi reless packet t ransmission apparatus 20 to
the wi reless packet t ransmission apparatus 30 is regarded to be the same .
15 That is, by t ransmi t t ing blocks, each of which has the same size, f rom the
wireless packet t ransmission apparatus 20 in an order , the blocks reaches
the receiving side wi reless packet transmission apparatus 30 in the order of
transmission from the wireless packet t ransmission apparatus 20.
Therefore, i t is possible for the packet data restorat ion circui t 35 of the
20 wireless packet t ransmission apparatus 30 to car ry out the packet data
restorat ion process wi th accuracy.
[0120] In the case of the exemplar y embodiment 2, the wi reless
packet t ransmission apparatus 20 transmi ts the blocks by use of two
wireless circui ts r10 and r20. Accordingly, i t is desi rable f rom a point of
25 view of data transmission ef ficiency that at least one out of number of the
plural blocks having the second data size and number of the plural blocks
having the third data size is even, since i t is possible to send one block via
the wi reless ci rcui t r10 and the other one block via the wireles s ci rcui t r20
at the same t ime. In the case that n (integer) wireless ci rcui ts are used, i t is
39
desi rable due to the same reason that at least one out of number of the
plural blocks having the second data size and number of the plural blocks
having the third data size is a n mul t iple.
[0121] In the case that the size of the packet data can be divided by
a speci fic data size which is equal to or smal ler than the fixed block size 5 M
and is equal to or larger than the minimum block size m, the packet data
division uni t 221 may divide the packet data into t he blocks each of which
has the speci fic data size. For example, in the case that the size X of the
packet data is 1400 bytes, the packet data division uni t 221 may divide the
10 packet data so as to generate 7 blocks of 200 bytes. That is, the second data
size and the thi rd data size may be the same each other .
[0122] However, by set t ing the second data size to be the fixed
block size M, and the thi rd data size to be a value which is smal ler than the
fixed block size M and is equal to or larger than the minimum block size m,
15 i t is possible for the packet data division circui t 22 to car ry out the
division process wi th ef ficiency. The reason is that i t is unnecessary for
the packet data division ci rcui t 22 to car ry out the division process on the
basis of the speci fic data size.
[0123] Furthermore, by showing an example, the division process
20 ment ioned above wi l l be explained. In the case that the size X of the packet
data is 300 bytes, the packet data division uni t 221 divides the packet data
to generate data whose data size is 256 bytes (cor responding to one block
having the fixed block size M), and the residual data of 44 bytes. The
residual data has a data size which is smal ler than a residual data m.
25 Accordingly, in this case, the packet data division uni t 221 may divide the
packet data into a block which has a data size of 200 bytes (second data
size) , and a block which has a data size of 100 bytes (thi rd data size) . Also
by car rying out the above-ment ioned process, i t is possible to transmi t the
packet data since the packet data division uni t 221 can divide the packet
40
data into the blocks each of which has a value equal to or larger than the
minimum block size m. Furthermore, the packet data division uni t 221 may
divide the packet data into a block which ha s a data size of 150 bytes
(second data size) , and a block which has a data size of 150 bytes ( thi rd
data size)5 .
[0124] In Fig. 7C, on the basis of data of 512 bytes (cor responding
to 2 blocks each of which has the f ixed block size M) and the residual dat a,
the packet data division uni t 221 may generate 1 block which includes the
residual data, and 2 blocks each of whose sizes is equal to or smal ler than
10 the fixed block size M and is equal to or smal ler than the minimum block
size m (generate a total of 3 blocks). Also by carrying out the
above-ment ioned process, the packet data division uni t 221 can generate
blocks each of which has a data size equal to or larger than the minimum
block size m. Simi larly, by carrying out (n+1) division to data
15 corresponding to n blocks (n is an integer ) each having the fixed block size
M, and the residual data, the packet data division uni t 221 may generate
(n+1) blocks each of whose data sizes is equal to or smal ler than the fixed
block size M and is equal to or larger than the minimum block size m. As
far as blocks each of whose data sizes is equal to or smal ler than the fixed
20 block size M and is equal to or larger than the minimum block size m are
generated, the packet data division uni t 221 may divide data into (n+2) or
more blocks. However , by generat ing a block, which includes the residual
data, on the basis of only the residual data and data which is cor responding
to one block having the fixed block size M, the packet data division uni t
25 221 can generate a block, whose s ize is equal to or larger than the
minimum block size m and which includes the residual data, in smal l
number of processes.
[0125] Here, a size of data, which is used when dividing the
residual data and the data into blocks, is changed according to a rat i o of
41
the minimum block size m to the fixed block size M. For example, a case
that a value of the minimum block size m is two thi rds of the fixed block
size M wi l l be considered. In this case, i t is necessary to generate a total of
3 blocks, that is, 1 block which includes the residual data, and 2 blocks,
each of whose data sizes is equal to or smal ler than the fixed block size 5 M
and is equal to or larger than the minimum block size m, on the basis of
data of 512 bytes (corresponding to 2 blocks each of whic h has the fixed
block size M) and the residual data. The reason is that , in the case of using
only the residual data and data of 256 bytes (corresponding to one block
10 which has the fixed block size M) , i t is impossible for the packet data
division uni t 221 to generate blocks each of whose data sizes is equal to or
larger than the minimum block size m.
[0126] It is possible to make the data t ransmission apparatus (or,
data division apparatus) carry out the process flows shown in the
15 exemplary embodiments 1 to 4 as one of control methods. For example, the
data t ransmission apparatus (or, data division apparatus) may be inst ructed
to car ry out the f low as a cont rol program
[0127] Here, the control program, which is executed by the data
transmission apparatus (or, data division apparatus), is stored by use of
20 various types of non- transi tory computer readable medium, and can be
provided to a computer . The non-transi tory computer readable medium
includes various types of tangible storage medium. An example of th e
non-transi tory computer readable medium includes a magnet ic record
medium (for example, flexible disk, magnet ic tape, hard disk drive), a
25 magnet ic opt ical record medium ( for example, magnet ic opt ical disk),
CD-ROM, CD-R, CD-R/W, a semiconductor memory ( for example, mask
ROM, PROM (Programmable ROM), EPROM (Erasable PROM), a flash
ROM, RAM (Random Access memory) . Moreover, a display control
program may be provided to a computer by use of the various types of
42
non-transi tory computer readable medium. An example of the t ransi tory
computer readable medium includes an electric signal , an opt ical signal
and an electromagnet ic wave. The t ransi tory computer readable medium
can provide a computer wi th the cont rol program via a wi red
communicat ion l ine, such as a wi r e, an opt ical fiber or the l ike, or 5 a
wireless communicat ion l ine.
[0128] Hereinaf ter, various embodiments wi l l be added.
(Supplementary note 1)
A data t ransmission apparatus which divides transmission data into
10 blocks each of which has a predetermined data size, and t ransmi ts the
blocks to a t ransmission dest inat ion apparatus, comprising:
a t ransmission data division uni t which divides the transmission
data into the blocks;
a t ransmission uni t which transmi ts the blocks divided by the
15 transmission data division uni t to the transmission dest inat ion apparatus;
a calculat ion uni t which calculates a size of residual data generated
by dividing the t ransmission data into the blocks each having the
predetermined data size; and
a residual data judgment uni t which judges whether the size of the
20 residual data calculated by the calculat ion uni t is smal ler or not smal ler
than a minimum data size which the t ransmission dest inat ion apparatus can
receive, wherein
in the case that the residual data judgment un i t judges that the size
of the residual data is smal ler than the minimum data size, the transmission
25 data division uni t generates a block, which includes the residual data and
whose data size is equal to or larger than the minimum data size, by
dividing the t ransmission data so as to make the block, which includes the
residual data, include a part of the t ransmission data other than the residual
data.
43
(Supplementary note 2)
The data t ransmission apparatus according to supplementary note 1,
wherein
the transmission data division uni t divides the t ransmission dat5 a
into one or more blocks each of which has the predetermined data size, a
block which includes the residual data, and a block having a fi rst data size
which is equal to or smal ler than the predetermined data size and is equal
to or larger than the minimum data size.
10
(Supplementary note 3)
The data t ransmission apparatus according to supplementary note 2,
wherein
the block including the residual data has a data size almost equal to
15 the fi rst data size.
(Supplementary note 4)
The data t ransmission apparatus according to supplementary note 1,
wherein
20 the transmission data division uni t divides the t ransmission data
into one or more blocks each of which has a second data size equal to or
smal ler than the predetermined data size and equal to or larger than the
minimum data size, and one or more blocks each of which has a third data
size equal to or smal ler than the predetermined data size and equal to or
25 larger than the minimum data size.
(Supplementary note 5)
The data t ransmission apparatus according to supplementary note 4,
wherein
44
the second data size is the predetermined data size and is di f ferent
from the thi rd data size.
(Supplementary note 6)
The data t ransmission apparatus accor ding to any one o5 f
supplementary notes 1 to 5, wherein
the part of the transmission data, which are included in the block
including the residual data and which are dif ferent f rom the residual data,
are data which just fol low or just precede the residual d ata in the
10 transmission data.
(Supplementary note 7)
The data t ransmission apparatus according to any one of
supplementary notes 1 to 6, wherein
15 in the case that the residual data judgment uni t judges that the size
of the residual data is equal to or larger than the minimum data size, the
transmission data are divided into a block which includes the residual data,
and a block which has the predetermined data size.
20 (Supplementary note 8)
The data t ransmission apparatus according to any one of
supplementary notes 1 to 7, wherein
in the case that the size of the residual data, which is calculated by
the calculat ion uni t , is 0, the t ransmission data division uni t divides the
25 transmission data into a plural i ty of blocks each of which has the
predetermined data size.
(Supplementary note 9)
A data division apparatus which divides t ransmission data into
45
blocks each of which has a predetermined data size, comprising:
a t ransmission data division uni t which divides the transmission
data into the blocks;
a calculat ion uni t which calculates a size of residual data generated
by dividing the t ransmission data into the blocks each having th5 e
predetermined data size; and
a residual data judgment uni t which judges whether the size of the
residual data calculated by the calculat ion uni t is smal ler or not smal ler
than a minimum data size which a t ransmission dest inat ion apparatus can
10 receive, wherein
in the case that the residual data judgment uni t judges that the size
of the residual data is smal ler than the minimum data size, the transmission
data division uni t generates a block, which includes the residual data and
whose data size is equal to or larger than the minimum data size, by
15 dividing the t ransmission data so as to make the block, which includes t he
residual data, include a part of the t ransmission data other than the residual
data.
(Supplementary note 10)
20 A data division method used by a data division apparatus which
divides transmission data into blocks each of which has a predetermined
data size, comprising:
calculat ing a size of residual data generated by dividing the
transmission data into the blocks each having the predetermined data size;
25 judging whether the calculated size of the residual data is smal ler
or not smal ler than a minimum data size which a transmission dest inat ion
apparatus can receive; and
generat ing a block, which includes the residual data and whose data
size is equal to or larger than the minimum data size, by dividing the
46
transmission data so as to make the block, wh ich includes the residual data,
include a part of the transmission data other than the residual data, in the
case that i t is judged that the size of the residual data is smal ler than the
minimum data size.
5
(Supplementary note 11)
The data t ransmission apparatus according to supplementary note 2
or 3, wherein
the transmission data division uni t generates one or more blocks
10 each of which has the predetermined data size before generat ing the block
including the residual data, and the block which has the t hird data size, and
wherein
the transmission uni t transmi ts the blocks, which the transmission
data division uni t generates, in turn.
15
[0129] Whi le the invent ion has been part icularly shown and
described wi th reference to exemplary embodiments thereof, the invent ion
is not l imi ted to these embodiments. It wi l l be understood by those of
ordinary ski l l in the art that various changes in form and detai ls may be
20 made therein wi thout depart ing f rom the spiri t and scope of the present
invent ion as defined by the claims.
[0130] This appl icat ion is based upon and claims the benefi t of
priori ty f rom Japanese Patent Appl icat ion Publ icat ion No. 2012 -164736,
fi led on July 25, 2012, the disclosure of which is incorporated herein in i ts
25 ent i rety by reference.
[ Industrial Appl icabi l i ty]
[0131] The present invent ion is appl icable to a technical field of
data t ransmission. For example, the present invent ion is appl icable to
47
packet data transmission including wi reless packet data t ransmission.
[Reference signs List ]
[0132]
1 transmission data generat ion apparatu5 s
2 receiving apparatus
3 and 4 L2SW apparatus
10 data t ransmission apparatus
11 t ransmission data division uni t
10 12 t ransmission uni t
13 calculat ion uni t
14 residual data judgment uni t
20 wireless packet transmission apparatus
21 t ransmission packet data buffer ci rcui t
15 22 packet data division ci rcui t
221 packet data division uni t
222 calculat ion uni t
223 residual data judgment uni t
23 and 24 wi reless sending ci rcui t
20 25 and 26 wi reless receiving circui t
27 and 28 received block data buf fer ci rcui t
29 packet data restorat ion circui t
30 wireless packet transmission apparatus
31 and 32 wi reless receiving circui t
25 33 and 34 received block data buf fer ci rcui t
35 packet data restorat ion circui t
40 wireless packet transmission apparatus
41 sending and receiving control ci rcui t
42 wireless sending circui t
48
43 wireless receiving circui t
44 t ransmission block data buf fer ci rcui t
45 packet data division ci rcui t
46 received block data buffer circui t
47 packet data restorat ion circui 5 t
50 wireless packet transmission apparatus
51 t ransmission and received data buf fer circui t
52 wireless sending circui t
53 wireless receiving circui t
10 54 t ransmission packet data buffer ci rcui t
55 received block data buffer circui t
60 wireless packet transmission apparatus
61 wireless receiving circui t
62 wireless sending circui t
15 63 sending and receiving control ci rcui t
70 wireless packet transmission apparatus
71 wi reless receiving circui t
72 wireless sending circui t
73 t ransmission and received data buf fer circui t
20 80 packet t ransmission apparatus
81 t ransmission packet data buffer ci rcui t
82 packet data division ci rcui t
90 packet t ransmission apparatus
91 and 92 received block data buf fer ci rcui t
25 93 packet data restorat ion circui t
49
WE CLAIM:
[Claim 1] A data transmission apparatus which divides t ransmission data
into blocks each of which has a predetermined data size, and transmi ts the
blocks to a t ransmission dest inat ion apparatus, comprising:
transmission data division means which divides the t ransmissio5 n
data into the blocks;
transmission means which transmi ts the blocks divided by the
transmission data division means to the transmission dest in at ion apparatus;
calculat ion means which calculates a size of residual data generated
10 by dividing the t ransmission data into the blocks each having the
predetermined data size; and
residual data judgment means which judges whether the size of the
residual data calculated by the calculat ion means is smal ler or not smal ler
than a minimum data size which the t ransmission dest inat ion apparatus can
15 receive, wherein
in the case that the residual data judgment means judges that the
size of the residual data is smal ler than the minimum data size, the
transmission data division means generates a block, which includes the
residual data and whose data size is equal to or larger than the minimum
20 data size, by dividing the t ransmission data so as to make the block, whic h
includes the residual data, include a part of the t ransmission data other
than the residual data.
[Claim 2] The data transmission apparatus according to claim 1, wherein
25 the transmission data division means divides the t ransmission data
into one or more blocks each of which has the predetermined data size, a
block which includes the residual data, and a block having a fi rst data size
which is equal to or smal ler than the predetermined data size and is equal
to or larger than the minimum data size.
50
[Claim 3] The data transmission apparatus according to claim 2, wherein
the block including the residual data has a data size almost equal to
the fi rst data size.
5
[Claim 4] The data transmission apparatus according to claim 1, wherein
the transmission data division means divides the t ransmission data
into one or more blocks each of which has a second data size equal to or
smal ler than the predetermined data size and equal to or larger than the
10 minimum data size, and one or more blocks each of which has a third data
size equal to or smal ler than the predetermined data size and equal to or
larger than the minimum data size.
[Claim 5] The data transmission apparatus according to claim 4, wherein
15 the second data size is the predetermined data size and is d i f ferent
from the thi rd data size.
[Claim 6] The data transmission apparatus according to any one of
claims 1 to 5, wherein
20 the part of the transmission data, which are included in the block
including the residual data and which are dif ferent f rom the residual data,
are data which just fol low or just precede the residual data in the
transmission data.
25 [Claim 7] The data transmission apparatus according to any one of
claims 1 to 6, wherein
in the case that the residual data judgment means judges that t he
size of the residual data is equal to or larger than the minimum data size,
the transmission data are divided into a block which includes the residual
51
data, and a block which has the predetermined data size.
[Claim 8] The data transmission apparatus a ccording to any one of
claims 1 to 7, wherein
in the case that the size of the residual data, which is calculated b5 y
the calculat ion means, is 0, the t ransmission data division means divides
the transmission data into a plural i ty of blocks each of which ha s the
predetermined data size.
10 [Claim 9] A data division apparatus which divides t ransmission data into
blocks, comprising:
transmission data division means which divides the t ransmission
data into the blocks;
calculat ion means which calculates a size o f residual data generated
15 by dividing the t ransmission data into the blocks each having the
predetermined data size; and
residual data judgment means which judges whether the size of the
residual data calculated by the calculat ion means is smal ler or not smal ler
than a minimum data size which a t ransmission dest inat ion apparatus can
20 receive, wherein
in the case that the residual data judgment means judges that the
size of the residual data is smal ler than the minimum data size, the
transmission data divis ion means generates a block, which includes the
residual data and whose data size is equal to or larger than the minimum
25 data size, by dividing the t ransmission data so as to make the block, which
includes the residual data, include a part of the t ransmiss ion data other
than the residual data.
[Claim 10] A data division method used by a data division apparatus
52
which divides t ransmission data into blocks each of which has a
predetermined data size, compr ising:
calculat ing a size of residual data generated by dividing the
transmission data into the blocks each having the predetermined data size;
judging whether the calculated size of the residual data is smal le5 r
or not smal ler than a minimum data size which a transmission dest inat ion
apparatus can receive; and
generat ing a block, which includes the residual data and whose data
size is equal to or larger than the minimum data size, by dividing the
10 transmission data so as to make the block, which includes the residual data,
include a part of the transmission da ta other than the residual data, in the
case that i t is judged that the size of the residual data is smal ler than the
minimum data size.