The present technology relates to an inlbnnaiion processing device.
30 Specifically, the present technology relates to an Information processing device and
an information processing method of exchanging information using wireless
communication and a program capable of causing a computer to perform the method.
Background Art
15 [0002]
In the related art, (here arc wireless communication technologies for
exchanging information using wireless communication. For example,
communication methods (for example, autonomous distributed wireless networks) of
autonomously performing mutual connection between information processing
20 devices that approach each other have been proposed. liy using such
communication methods, it is possible to exchange information between two
information processing devices using wireless communication even when connection
is not made wHh wired circuits.
[0003]
25 In autonomous distributed wireless networks, carrier senses are adopted as
adjustment methods of avoiding packet collision at the time of communicator]
between information processing devices,
[0004]
For example, wireless communiciilinn devices perlbrming transmission
'60 suppression by dynamically setting carrier sense level thresholds using desiied wave
powers as standards have been proposed (for example, sec Patent Literature 1).
SIMf^MWOOl
2/142
Citation List
Patent 1 ilerature
|0005|
5 Patent Literature I: JP 2007-142722A
Summary of Invention
Technical Problem
t0006]
10 In I be technologies of the above-described related ait, even when
transmission is possible at reception signal intensities equal to or less than Ibe earner
sense level thresholds, transmission can he set not to be perlonned at the time of a
desired-wave-to-interference power ratio at which transmission is erroneous.
[0007]
15 However, when the number ol' inforniation processing devices confirmed in
a network increases, excessive transmission suppression occurs and there ts a
concern of transmission efficiency of an enjire system deteriorating. Accordingly, it
is important to efficiently use radio resources while maintaining communication
quality.
20 [0OOK]
It is desirable to provide the present technology capable ol'efliciently using
radio resources.
Solution to Problem
2\-> foooy]
The present technology has been made to solve the above problem. A first
aspect of the present lecbnology is an information processing device including a
control unit configured to perform control such that reception of a packet is stopped
during the reception according Jo a first condition anil an operation is performed
,10 assuming that a carrier sense is an idle state for a time from start of the reception of
the packet lo stop of Ihe reception of Ibe packet according to a second condition, an
SJMr>ft!>HWOl)l
J/142
information processing method thereof and a program causing a computer to
perform ibe melhod. Thus, it is possible to obtain an operational effect in which the
reception of the packet is slopped during the reception according to the first
condition and the operalion is performed assuming that the cairicr sense is in the idle
f. stale for the time from start of the reeepbon o\' the packet. to ibe stop of the reception
of the packet according lo Ibe second condition.
(OOfOj
!n tiic first aspect, when ihc second condition is satisfied after the stop of the
reception of ibe packet, the control unit may perform conLrol such thai a hilency lime
11} corresponding to an inter frame space (IKS) docs not occur. Thus> \i is possible to
obtain an operational elleet in which, when the second condition is satisfied after !he
stop of the reception of flic packet, Ibe control is performed, such thut the latency lime
corresponding to the IFS does not occur.
[001 Lj
15 In the first aspect, when the second condition is satisfied after the stop of the
reception of the packet, the control unit may perform control such that a time length
from a transition time of the carrier sense to BUSY at ibe time oflbe reception of the
packet to a reception slop time is converted into a slot time and is subtracted from a
backoff counter. 'ITII.ES, it is possible lo obtain an operational eJTec-i hi which, when
20 the second condition is satisfied after the stop of the reception of the packet, the
control is performed such that a time length from a transition time of the carrier sense
to BUSY at the time of the reception of the packet to a reception stop time is
converted into a slot (itnc and is subtracted from a backoff counter,
[0012]
25 In She first aspect, when a result after the subtraction is a negative value, the
control tinit may treat the result as 0. Thus, it is possible to obtain an operational
effect in which, when the result afler the subtraction is the negative value, the result
is treated as 0.
]OOI3j
30 In the first aspect, when a result after the subtraction is a negative value, (he
control unit may set a value obtained by reluming the result to a positive vahic
4/142
corresponding to Ibe negative value so that the value does not exceed the backoff
counter before the subtraction, Thusv iL is possible So obtain an operational effect in
which, when ibe result after the subtraction is the negative value, the value obtained
by returning Ihc result positively to the value corresponding to ibe negative value is
5 set so that the value does not exceed the backoff counter before the subtraction.
[0014J
In the first aspect, the lirst condition may include a condition that a CRC
calculation insult obtained when a physical header of the packet during the reception
is a target not be identical to CRC information described in the physical header.
10 Thus, it is possible to obtain an operational effect hi which the condition that J he
CRC calculation result obtained when the physical header of the packet during the
reception is the target not be identical to the CRC information, described in Ibe
physical header is set as the first condition,
|0015j
15 In Ibe first aspect, when information regarding an identifier for identifying a
network ts present hi the physical header ol the packet.. the Eirst condition may
further include a condition that the information regarding the identifier be different
from a network identifier of a network to which (he information processing device
belongs. Thus, it is possible to obtain an operational effect in which, when the
20 information regarding the identifier for identifying (he network is present in the
physical header of the packet, (he condition that the information regarding the
identifier be different iiom the network identifier of the network to which the selfdevice
belongs is set as the first condition.
[0016]
KG In the first aspect, the first condition may further include a condition that a
preamble correlator output level of the packet dining the reception in antenna input
conversion be less than a threshold derived from information described in the
physical header of the packet. Thus, it is possible lo obtain an operational effect in
which the condition that the preamble correlator output level of the packet during the
30 reception in the antenna input conversion be less than the threshold derived from
information described in the physical header of the packet is set as the first condition.
ttP^olLWOi.lJ
5/1C!
[0017]
in the firs! aspeci, when information regarding an idenlifier liir identifying a
network is present in the physical header of the packet and the information, regarding
the identifier is identical lo a network, identifier of a network io which the
5 information processing device belongs, Ihe control unit may continue the reception
without stopping the rcceplion. Thus, it is possible lo obtain an operational effect in
which, when the information regarding the identifier Tor identifying the network is
present in the physical header of the packet and the information regarding the
identifier is identical to the network identifier of the network In which the self-device
10 belongs, the reception is continued without stopping the reception,
J00181
In the first aspect, the conlrnl unit may perform the derivation based on
matching between an index described in the physical header of the packet and a table
of thresholds shared in advance. Thus, il is possible Lo obtain an operational eileci
IFi in winch the derivation is performed based on the matching between the index
described in the physical header of the packet and Ihe table of thresholds shared in
advance.
[00191
In the first aspect, the control unit may perform the derivation through
20 conversion based on a value described in the physicid header of the packet and
information regarding a unit and quantization shared in advance. Thus, il is
possible lo obtain an operational effect in which the derivation is pedoimed through
the conversion based on the value described in the physical header and die
information regarding the unit and the quantization shared in advance,
25 [0020]
In the first aspect, the second condition may include the first condition.
Thus, it is possible to obtain an operational effect in which the second condition
including the first condition is used.
[0021]
30 In the first aspect, the control unil may deiemiine necessity and nonnecessity
of Hie operation using a condition (bat reception power of the packet. during
SPSttttllWOfJl
{..•142
Ihe inception be less than El pii>dccided energy deletion threshold, as the second
condition. Thus, it is possible to obLain an operational cflcct in which Lhc condition
thai reception power of the packet during the reception be less than the pre-decided
energy detection threshold is set as the second condition.
5 [0022]
In the first aspect, the control unit may determine necessity and nonnecessity
of the operation using a condition that transmission suppression by virtual
carries- sense mil be applied at the time of stopping ot ihe reception of Ihe packet. as
the second condition. Thus, il is possible to obtain an operational effect in which
10 the condition thai Hie transmission suppression by the virtual carrier sense not be
applied at the time of stopping of Ihe reception of the packet is set as the second
condilion,
[O023|
In the first aspect, the control unit may determine necessity and non-
55 necessity of the operation using a condilion that a CRC calculation result obtained
when a physical header of the packei is a target not lie identical to CRC information
described in The physical header and a preamble correlator output level of the packet
in antenna input conversion be less than a minimum packet detection threshold
among applicable packet detection thresholds, as the second condition. Thus, il is
20 possible in obtain an operational effect in which Ihe necessity and non-necessity of
the operation is determined using, as the second condition, the condition that Ihe
CRC calculation result obtained when Ihe physical h^der of the packet is the target
not be identical to the CRC information described in the physical header and the
preamble c o l l a t o r output level be less than the minimum packet detection threshold
25 among the applicable packet detection thresholds,
10024]
In the first aspect, when the second condition is not satisfied after slop of Lhc
reception of the packet, the control unit may perform control such that transmission
from the information processing device during a continuity period of the packei
30 transfer is prohibited. Thus, it is possible to obtain an operational clTect in which,
when Ihe second condition is not satisfied after the slop of Ihe reception of Ihe packet,
Hl^ftfMliWOflt
7/M?.
Ilie iransraission from Ihe information processing device during a continuity period
of the packet transfer is prohibited.
[0025]
In ihe first aspect, when the second condition is not satisfied after the slop of
Ti the reception of the packet and the hansmisston from the inlbimalion processing
device duiing she continuity period of the packet transfer is prohibited, the control
unit performs controJ such thai EL reply to a frame which is destined for Ihc
information processing device and requests the reply is transmitted when the frame is
received. Thus, it is possibic to obtain an operational efleel in wflich: when the
10 second condition is not satisfied after me stop of the reception of the packet and the
transmission from She self-device during Ihe continuity period of the packet transfer
is proliibitcd, the reply to the frame which is destined for the self-device and requests
the reply is transmitted when the frame is received,
15 Advantageous Effects of Invention
[0026J
According to the present technology, it is possible to obtain the
advantageous eJTecl in which radio resources can he efficiently used. Note that the
advantageous effects described above are not necessarily limitative, and the
20 advantageous effects described in the present disclosure may be acincved,
Brief Description of Drawings
|0027|
[FTG 1] FIG 1 is a diagram showing a system configuration example of a
2ft communication system \ 0 according to a first embodiment of (he present technology.
[FIG 2] FIG. 2 is a diagram showing a syslem configuration example of (be
communication system 30 according to the first embodiment of the present
technology,
j R t ! 3j FIG 3 is a diagram showing a system configuration example of the
30 communication system SO according to Ihe Sirst embodiment of the pi'esent
tcclmoiogy.
K.-'I42
[FKi. 4| FIG 4 is a diagram showing an example of a transmission anil reception
process by information processing devices inducted in (he communication system 10
in a time seiies manner according to the first embodiment of the present technology,
| MG. 5] FIG. 5 is a block, diagram showing a functional con J i munition example of an
5 information processing device 100 according to the fust embodiment of tire present
technology,
[FIG. 6] FIG. 6 is a sequence chad showing a communication processing example
between devices included in the communication sywlem 10 according Lo Ihe first
embodiment of the present technology.
10 [FIG 7] FIG 7 is a diagram showing ail example of the format of a PPDU exchanged
between the devices Included in the communication system 10 according to the first
embodiment of the present technology.
[FIG 8j FKI 8 Is a sequence chart showing an example of a connection process
between the devices included in the communication system 10 according to the firsl
J f> embodiment ofihe present tcclinology.
jFIG 9| FIG 9 is a diagram schematically showing an example of content of a setting
information list 161 stored in a memory of an information processing device 200
according to the first embodiment ofihe present technology.
[FIG. 10] FIG 10 is a flowchart showing an example of a processing order of a
20 physical header parameter decision process by the information processing device 200
according to the first embodiment of the present technology.
[FIG 1! J FIG 1 i is a diagram showing an example of Ihe configuration of a
correlator included in die information processing device 200 according to the first
embodiment ol the present technology,
25 [FIG 12] MG 12 is EI diagram showing a system configuration example of the
communication system 10 according to the first embodiment of the present
technology.
| FKi HJ FIG. 13 ts a diagram showing a system configuration example of the
communication system 10 according to the first embodiment of the present
.10 technology.
[FIG 14] FIG 14 is a diagram showing an example of a beacon frame Ibimat
ttra>ftr> n wool
l)-!\A2
exchanged between the devices included in the communication system 11) acceding
Eo (lie first embodiment of the present technology,
[FIG, 15} FIG. 15 is a sequence chart showing an example of a physical header
parameter sharing process between the devices included in the communication
Ti system 10 according to the first embodiment of the present technology.
[FIG 16] FIG 16 is a flowchart showing an example of a processing order of a use
physical header decision process by the information pi-ocessing device 101) according
to the first embodiment of the present technology.
[FKL 17j FIG 17 is a flowcliart showing an example of a processing order of a
11} transmission and reception process by the information processing device 100
according to Ihe iirsl embodiment of the present technology.
|FIG IS] FIG IK is a flowchart showing a packet detection determination process in
the transmission and reception process by the information processing device IfX)
according to Ihe first embodiment of the present technology,
15 [FIG 19] FIG 19 is a flowchart showing an example of a processing order of the
transmission and reception process by the mlbnTialion piocessing device 100
according to a second embodiment of Ihe present technology.
[FIG. 20] FIG 20 is a diagram showing an example of the format of a TPDII
exchanged between devices included in a communication system 10 according to a
20 third embodiment of the present technology.
jRU 21] HG 21 is a diagram showing an example of the format of a PPDU
exchanged between devices included in a communication system 10 according to a
fourth embodiment of the prcscnt technology.
[FIG 22] FIG 22 is a Howchart showing a packet detection determination process in
25 the transmission and reception process by the information processing device 100
according to the fourth embodiment of the present technology.
| HG 23j RCi. 23 is a diagram showing an example o\~ a beacon frame format
exchanged between devices included in a communication system 10 according Lo a
fifth embodiment of the present technology.
30 [FIG 24] FIG 24 is a sequence chart showing an example of a connection process
between the devices included in the communication system 10 according lo the fifth
\iV\41
embodiment of the present technology.
(T'!G 251 l"-'Iti 25 ts a flowchart showing a packet detection delerminahon process in
the transmission and reception process by Ihe information processing device 100
according to the fifth embodiment of Ihe present technology.
5 [FIG 26] FIG. 26 is a flowchart showing a packet detection determination process in
the transmission and reception process by an information processing device 100
according to a sixth embodiment of the present technology.
[FIG. 27] FIG 27 is a diagram showing an example of the configuration of a
correlator included in the information processing device 100 according to the sixth
1U embodiment of the piesent technology,
JRti. 2tt] R(i 2K is a digram showing a system configuration example of a
communication system 50 according to a seventh, embodiment of the preseni
technology.
[FIG 20] 11G 29 is a sequence chart showing a communication processing example
15 between devices included in a communication system .50 according to the seventh
embodiment of the present technology.
[FIG 30] FIG. 30 is a sequence chart showing a communication processing example
between devices included in a communication system 50 according to an eighth
embodiment of the present lechnology.
20 [FIG. 31j FKt 31 is a diagram showing an example of the formal of a PPOU
exchanged between the devices included in the communication system 30 according
to a ninth embodiment of the present technology.
[FIG 32] i'lG. 32 is a diagram showing an example of a beacon frame format
exchanged between the devices included in the communication system ! 0 according
25 to the ninth embodiment of the present tcciinology.
[FTG. 33] FIG. 33 is a diagram showing the How of a baeko fi" process in the llilili
802.31 standard.
[FECI 34] FIG. 34 is a diagram, showing the Row of a backoff pvticess by an
information processing device 100 according to the ninth embodiment of the present
30 technology,
[FIG 35] FIG. 35 is a diagram showing the flow of a backoff process by Llie
HP35a51lWOUI
M.'!42
information processing device 100 accoiding lo ihe niiiLh embodiment of Ihe present
technology,
[FECI 36 J FIG. 36 is a flowchart showing an example of w processing order of a use
physical header decision process by the in formation processing device 100 according
5 to the ninth embodiment of the present technology,
[FIG. 37j FIG. 37 is a flowchart showing an example of a processing order of a
transmission and reception process by the information processing device 300
according to Ihe ninth embodiment of the present technology,
fl'IG 38] FIG. 38 is a diagram showing an example of a relation (process
10 classification (able) between a physical header and a process performed by the
information processing device 100 according to the ninth embodiment of the present
technology,
[FIG 39J FIG 39 is a flowchart showing a packet detection and reception
determination process in the transmission and reception process by the information
Ifi processing device 100 according to theninlh embodiment of the present technology.
jFJG 401 FIG 40 is a diagram showing an example of the format of a ¥¥BU
exchanged between devices included in a communication system 10 according to a
tenth embodiment of the present technology.
[FIG. 41] FIG. 41 is a diagram showing an example of a relation (process
20 classification table) between a physical header and a process perlbrmed hy an
information processing device 100 according to a tenth embodiment of the present
technology.
[FIG. 42] FIG 42 is a flowchart showing a packet detection and reception
determination process in the transmission and reception process by the information
25 processing device 100 according to the tenth embodiment of the present technology.
[FIG 43] FIG 43 is a diagram showing an example of the format of a PPDU
exchanged between devices included in a communication system 10 according to an
eleventh embodiment of the present technology.
[FIG. 44] FIG. 44 is a diagram showing an example of a beacon frame formal
,30 exchanged between the devices included in the com muni cation system 10 according
io the eleventh embodiment of the present technology,
BP^wmwooi
v)i\'\:j_F!Ci 45] FIG. 4.S is a jltnveliarl showing an example of a processing eider of a use
physical header decision process by (he nilbrmation processing device 100 according
lo the eleventh embodiment of the present technology.
[FIG. 46| FIG 46 is a diagram showing an example of a relation {process
5 classification table) between a physical header and a process performed by the
information processing device 100 according to the eleventh embodiment of the
present technology.
[FIG 47] FIG 47 is a diagram showing an example of the format of a PPDU
exchanged between devices included in a communication sysleni fO according to a
10 twelfth embodiment of Lbe present technology.
|FKI 4Rj F!G 4K is a flowchart showing yn example of a processing order of a
physical header parameter decision process by the information processing device 200
according to the twelfth embodiment of the present technology.
jilG. 49] lrIG. 49 is a diagram showing an example of a beacon frame format
15 exchanged between Ihe devices included in the communication system 10 according
to the twelfth embodiment of the present technology.
[FIG 50] FIG. 50 is a diagram showing an example of a relation (process
classification tabic) between a physic;]] header and a process performed by the
information processing device 100 according to the twelfth embodiment of the
20 present technology.
[FIG 51] FIG 51 is a block diagram showing an example of a schematic
configuration ofa smartphone.
[FIG. 52] FIG 52 is a block diagram showing an example of a schematic
configuration of a car navigation device,
25 [FIG 53] TIG 53 is a block diagram showing an example of a schematic
configuration of a wireless access point
Dcscri ption of Kmbodimen t(s)
[0028]
30 Hereinafter, modes for carrying out the present technology (hereinafter
referred lo as embodiments) will be described. The description will be made in the
>spy?jyaiivvoui
I.VI42
loElowhig order
3. I'iist embodiment (example in which Link Strength Category field is set up in
SIGNAL field of" 3KKK M02.ll standard and packet detection condition is seL
according to information processing device)
5 2. Second embodiment (example in which no transmission is performed when packet
detection determination result is only-energy dclcciion arid transmission suppression
is set)
3. Third embodiment (example in which Link Strength Category field is set up in
Service field of IEEE 802.11 standard)
10 4r FourJh embodiment (example in which plurality (if preamble sequences with
different detection thresholds are used on transmission side and preamble correlation
deleetor applied by RSST is switched on reception side)
5. Fifth embodiment (example in which physical header used by subordinate
information processing device is selected by master station side)
IFi 6. Sixth embodiment (example in which plurality of PLCP preambles for
discrimination arc generated by processing part of original sequence rather than
completely different sequences)
7. Seventh embodiment (example in which direct com mimical ion between slave
stations is performed)
20 H. Eighth embodiment (example in which physical header parameters used between
direct links are decided by slave station)
9. Ninth embodiment (example in which information regarding identifier of BSS is
stored in signal field of IEEE 802.11 standard)
KK Tenth embodiment (example in which plurality of preamble sequences are
£5 defined and COLOR information is used together)
11. Eleventh embodiment (example in which physical header parameter decision
process is omitted)
12. Twelfth embodiment (example in which field storing information regarding
identifier of BSS in SIGNAL lick! ofliiiili 802.11 standard is set up)
30 } 3. Application examples
[0029]
SIM58r>||\VO{]l
-•"I Firs! embodiment-"'
{Configuration example of communication system]
FIG 1 is a diagram showing a system configuration example of a
communication system 10 according to a first embodiment of the picsent technology,
5 [0030]
The communication system 10 is configured to Include information
processing devices ] 00 to 103 and information processing devices 200 ami 201.
T0031]
'Hie information processing devices 100 to E03 are, for example, portable
10 information processing devices thai have a wireless communication function. Here,
ihe portable in formal inn processing devices are, for example, information processing
devices such as smartphones, mobile phones, or tablet terminals. The information
processing devices 100 k> 303 arc assumed to have a communication function in
conformity with, for example, a wireless local area neLwork (LAN) standard of
15 Institute of Electrical and Electronic Engineers (IEEE) 802.1 L As the wireless
T.AN; for example, Wireless l-idclity (Wi-Fi), Wi Fi Direct, or Wi-Fi CERTIFIED
Miracast specification (technical specification name: Wi-Fi Display) can be used.
Wireless communication using another communication scheme may be used.
[00321
20 The information processing devices 200 and 201 arc, for example, fixed
Information processing devices that have a wireless communication function. Here,
the fixed information processing devices are, for example, information processing
devices such as access points or base stations. As in the information processing
devices 100 to 103, the information processing devices 200 and 201 are assumed to
25 have a communication function in conformity with, for example, a wireless LAN
standard of IEEE 802,11. Wireless communication using another communication
scheme may be used.
[0033]
'Hie information processing devices 200 and 201 are assumed to function as
30 master stations and the inlbrmation processing deviees 100 to 103 are assumed to
function as slave stations. Thai is, in the first embodiment of the present technology,
KiTtofitfMWOOl
lfvl'1?
a communication example between master and slave stations in a star type topology
configured by (ho master and subordinate slave stations will be described. In Ihe
first embodiment of the present technology; a communication example in which a
destiimlkm for Iransmission by subordinate slave stations is restricted to a master
5 station will be described.
[0034]
The information processing devices tOO knd 302 and (he information
processing devices 200 and 203 are assumed to have specific functions (specific
[unctions deseiibed in each embodiment of the present technology). Conversely,
10 the information processing devices KJl and 103 arc assumed to have no specific
lundion. In Ibis way, ihe information processing devices that have no specific
function arc referred to as legacy devices, llie specific function will be described
in each embodiment of the present technology. The Jcgacy devices can be
configured as, for example, information processing devices that have a
15 communication function in conformity with a wireless LAN standard of IEFF
802,1 Ui1TFFFR02,llg, TRHh:S02.iln, or IEF.E 802,llac,
|0035|
In the first embodiment of the present technology, a communication
example between the devices when the information processing devices 100 and 101
20 are connected and the information processing devices 201 and 102 arc connected will
be described.
[0036]
FIG. 3 shows an example in which the ^omnium cat ion system 10 is
configured of four slave stations (the information processing devices 100 to 103), but
an the number of slave stations (the information processing devices) is not limited to 4.
That is, an embodiment of the present technology can also be applied to a
communication system configured of three or five or more slave stations
(information processing devices).
[0037J
30 In a relation between two information processing devices performing
communication, one of the information processing devices may serve as a master
slave and Ihe other information processing device may serve as a slave station,
Connection between two into million processing devices may be direct
com muni eali (.>3i connection between slave stations.
J003KJ
[j Here, in an autonomous distributed wireless network, a scheme referred to
ELS carrier sense is generally adopted as an adjustment structure for avoiding packet
collision. The carrier sense is a. scheme of monitoring a nearby wireless situation
lor a given time and conlirmiug whether there is another information processing
device performing transmission before performing transmission. When reception
10 power equal to or greater limn a threshold is detected during the confirmation, a
wireless stale is determined to be a busy slate, a transmission operation is stopped,
and thus the transmission is no! performed.
[0039]
In the carrier sense, there are two kinds of defection algorithms: preamble
15 detection in which detection is performed through power comparison between
correlator outputs of specific preambles and energy deteclion in which detection is
performed through power comparison between received signals. In general, the two
kinds of defection algorithms arc used together, Hereinafter, the two kinds of
detection algorithms arc collectively inferred to as the carrier sense in the description
20 unless otherwise slaied,
I0U40]
As described above, when the number of information processing devices in
a network increases, there is a concern of excessive transmission suppression and a
situation in which (ransmtssion efficiency of an emive system deteriorates in She
25 above-described carrier sense scheme.
[0041]
Here, an example of a positional relation hi which such a situation arises
will be desciibed vviih reference to 11G. 1, In FIG. 1, there are two master stations
(the Information processing devices 21)0 and 201) and four slave stations (the
30 information processing devices 100 to 103). In FIG. 1, ihe infoiraalion processing
devices 300 and 101 arc connected to the information processing device 200 and the
17/142
jnlbrmahon processing devices 302 and 10^ are connected to Ihe inlormation
processing device 201 to perform communication with one another. In FIG 1,
connection relations between the devices are scriemaiiealty indicaled by dotted Sines.
[0042J
5 in FIG I, the inlonnatiori processing devices 300 to 103, 200, and 201 arc
assumed jo be present in a posihonal relation in which transmission of ail the
information processing devices can be rnntnaily detected by the carrier sense,
[0043]
Here, for example, the information processing device 100 is assumed to
10 perform transmission to Lhe information processing device 200 and the information
processing device 3 02 is assumed to perform transmission to the information
processing device 201,
[0044]
j Bxamplc of carrier sense detection range j
15 FIGS, 2 and 3 arc diagrams showing system configuration examples of Ihe
communicator! system 10 according to the fust embodiment of the present
technology, FIGS, 2 and 3 show examples in which carrier sense detection ranges
of the information processing devices in mc example shown in FIG. I overlap,
|O045]
W In FTGS, 2 and 3, carrier sense detection ranges i 1 to 16 of the information
processing devices 100, 102, 200, and 201 are schematically indicated by dotted
circles,
j()046t
Specilical1y; in FKiS. 2 and 3, the carrier sense detection range 11 indicates
2fi a carrier sense detection range of the information processing device 200 and the
carrier sense deleetion range 32 indicaies a carrier sense detection range of Jhe
information processing dev;ee20t[0047]
!n FIG 2, the carrier sense detection range 13 indicates a carrier sense
30 deletion s-ange of the information processing device 100 and the currier sense
detection range 34 indicates a carrier sense deleclion lange of the information
is/J 42
processing ilcviet; 102.
[004K|
In FTG \ ihe carrier sense detection range \5 indicates a carrier sense
dei.cel.ioi] range of the information processing device 100 after the carrier sense
5 detection range 13 shown in FICi. 2 is changed. The carrier sense deSection range 1G
indicaLes a cai-Hcr .sense detection range of the information processing device H>2
alter the carrier sense detection range 34 shown in FIG 2 is changed.
[0049]
As described above, the carrier sense is an example ol the adjustment
10 structure for avoiding packet collision and is a scheme of performing transmission
suppression according to whether Lherc is another information processing device
performing transmission, 'I'he carrier sense delection range is decided to
correspond to a Ihrcshold used at Ihe time of detection of a signal transmitted from
another information processing device.
15 [00.50]
Here, tor example, it is assumed that the information processing device 100
pcifornis the carrier sense to perform transmission while the information processing
device 102 performs transmission to the information processing device 201. lor
example, when the information processing device ! 00 dctecls the transmission of Ihe
20 information processing device 102; the transmission is suppressed, and thus the
transmission may not be performed until the transmission of the information
processing device 102 ends.
|00511
However, even when the information processing device 100 performs the
25 transmission to the information processing device 200 during the transmission by Ihe
information processing device 102, the information processing devices 200 and 203
which arc reception sides can also perfonn reception according to a ratio between
desired waves and interference waves. The desired waves are radio waves from the
information processing device 100 to the information processing device 200 or radio
MWOoi
2?n <\?
bodies of various dafa Iramcs, data packets, and the. like, hor example, when a
transmission operation is performed, (he data processing imil 110 generates vaiiotis
data flames and data pack els and supplies the various data frames and data packets to
the transmission processing unit 120 in response lo « lequest from an upper layer.
5 I'or example, when a reception operation is performed, the data processing unit 110
processes and analyzes various data frames and data packets supplied from (he
transmission processing unit 120,
[0066]
The trans mission processing unit 120 performs various transmission
10 processes under the conlrol of the contiol unit 150. lor example, when a
transmission operation is performed, the transmission processing unit 120 performs a
process such as addition of a header or addition of an error detection code to a packet
generated by Ibe daJa processing unit 310 for media access control. For example,
the transmission processing unit 120 performs a process such as addition ofa Media
15 Access Conlrol (MAC!) header lor the MAC or addition of an error detection code lo
a packet generated by the data processing unil 310, Then, the transmission
processing unit 120 supplies the processed data to the modulation and demodulation
unit 130.
[0067]
20 When (he carrier sense is used, the transmission processing unit 120
calculates a Network Allocation Vector (NAV) lo be added. Here, as described
above, the tamer sense is an example of the adjustment structure for packet collision
avoidance and is a scheme of describing a transmission suppression time in content
of a wireless packet and setting transmission suppression in an inibrmaLion
25 processing device receiving the packet. Ihc NAV is the transmission suppression
time,
S0068|
For example, when a reception operation is performed, the transmission
processing unit 120 performs a reverse process (for example, packet error detection
r&0 or analysis and removal ol a MAC header) to the liansmission operation on a bit
stream supplied from the modutalion and demodulation unit ! 30. Then, when it is
2VI42
conJirmed thai there is no error in the dala friimc based on ihe error detection code.
the trails mission processing uml 120 supplies various data frames Ln the data
processing unit I 10.
j006«l
5 The transmission processing unit 120 performs a virtual carrier sense
process. In this case: when the NAV is set in (he header oHhe received packet and
the transmission suppression is applied, the transmission processing unit 120 notifies
the control unit 150 that [he NAV is set and Ihe transmission suppression is applied.
10070]
10 The modulation and demodulation unit 130 performs modulation and
demodulation processes under the control o!" the control unit 150. For example.
when a transmission operation is performed, the modulation and demodulation unit
HO peiTorms encoding, interleaving, modulation, and addition of a P U T header and
a PLCP preamble on the bit stream input from the transmission processing unit 120
15 based on coding and a modulation scheme set by the control unit I .SO, Then, the
modulation and demodulation urn) 130 generates a data symbol string and supplies
the data symbol siring to the wireless interface unit 140,
[0071J
For example, when a reception operation is performed, the modulation and
20 demodulation unit 130 performs a reverse process to the transmission operation on
an input from the wireless interface unit 140 and supplies the result to the
Iransmission processing unit 120. The modulation and demodulation unit 130
pciforms a carrier sense process. In this case, when reception power equal lo or
greater than a threshold is detected or a value of preamble correlation equal to or
25 greater than a predetermined output is detected, the modulation and demodulation
unit 130 determines that a wireless slate is a busy state and nolilies the control unit
I50thatthcwireiess stale is the busy state,
[0072J
The wireless interlace unit 140 is an interface that is connected to another
Itfl information processing device to transmit and receive various kinds of information,
I'br example, when. a transmission operation is performed, the wireless interface unit
SKttfi">MWO0]
2'J/W
140 converts an input from the modulation and demodulation unit ] 30 info an analog
signal, performs amplification, filtering, and frequency upconverting, and (ransmds
the result as a wireless signal from the antenna 141. h'or example, when a reception
operation is perii/mied. the wireless interlace unit 140 performs a reverse process in
5 the transmission operation on an input from (be antenna 14! and supplies llie result
to the in oil in ali on and demodulation unit 130,
100731
The control unit 150 controls reception and transmission operations of each
of the data processing unit 130, the transmission processing unit J20: the modulation
10 and demodulation unit 130, and the wireless interface unit 140. lor example, the
control unit ISO perlbrms delivery of infoimalion between ihe units, selling of
communication parameters, and scheduling of packets in the transmission processing
unit 120, For example, when the control unit 150 receives notification of carrier
.sense results from the modulation and demodulation unit 3 30 am! ihe transmission
15 processing unit 120, the control unit 130 performs each process related to setting of
ihe transmission suppression or cancellation of the setting based on the notification.
["00741
For example, a control unit (corresponding lis Ihe control unit 150) nl" the
information processing device 200 performs control such that physical headers (for
20 example, a PLCP preamble and a PLCP header) used for packets transmitted by
another information processing device are transmitted to another information
processing device using wireless communication,
100751
For example, the control unit 150 performs control such that one header is
2!i selected from a plurality of physical header candidates (for example, PLCP
preambles and PLCP headers) and is used for a transmission target packet. Here,
the plurality of physical header candidates correspond to information regarding a
plurality of physical headers (tor example, PLCP preambles and PT CP headers)
transmitted from the information processing device 200.
?.0 [0076J
Lor example, the conlrol anil of the information processing device 200
.SIMfiSriliWOOl
25/142
performs control suck thai packet detection conditions (for example, detection
thresholds of 'he PT.CT preambles) used by -mother information processing device
arc transmitted to another information processing device using wireless
communication,
ft [0077J
1'or example, the control unit 150 performs control such that one packet
detection condition is selected to be used Irom a plurality of packet detection
conditions (for example, detection thresholds of the PLCP preambles) in regard to a
plurality of packets transmitted from the information processing device 200 using
10 wireless communication. Ileie, (he plurality of paekct detection conditions
correspond to the plurality of packet detection conditions transmitted from Lhe
information processing device 200,
[0078]
For example, the control mitt 150 performs eonjrol such thai <.ma reception
l!i operation is selected to be performed from a plurality of reception operations in
regard to a plurality of packets transmitted from the information processing device
200 using wireless communication. The plurality o!" reception operations will be
described according to the first to eleventh embodiments of the present technology,
[0079J
HO The memory 160 has a role of a working area of data processing by the
control unit 150 or a function of a storage medium that retains various kinds of data.
As the memory 160, for example, a storage medium such as a non-volatile memory, a
magnetic disk, an optical disc, or a magneto-optical (MO) disc can be used. As the
non-volatile memory, for example, an electrically erasable programmable read-only
25 memory (F.EPROM) or an erasable programmable ROM (RPROM) can be used,
As the magnetic disk, for example, a hard disk or a discoid magnetic disk can be
used. As the optical disc, for example, a compact disc (CD), a digital versatile disc
recordable (DVD-R), or a Blu-TCay Disc (BD: registered trademark) can be used,
[0080]
30 In each embodiment of the present technology, an example in which each
transmission succeeds when uplink transmission from the information processing
ii;p;^H.->nwou]
26/142
device 100 lo Ihe inforination processing device 200 and uplink transmission Iron)
ihe information processing device ]02 to the information processing device 201 arc
performed simiHlaneoLisly (or substantially simullancously) will be described. An
embodiment nl~ the present technology can also be apphed to transmission between
fi the information processing devices other than such transmission.
[0081]
[Coin muni cat ion example]
1TG 6 is a sequence chart showing a communication processing example
between Ihe devices included in the communiealion system 10 according to the first
10 embodiment of the present technology,
[0082]
FIG 6 shows a communication processing example when uplink
transmission from ihe information processing device 100 to the tnlbitnation
processing device 200 is performed. The same also applies to a relation between
15 other information processing devices (for example, the information processing
devices 102 and 201).
|00K3|
First, a connection process between the inlbrmalion processing devices 100
and 200 is performed (•101), Ihe connection process will be described in detail with
20 reference to FIG 8,
j0084|
Subsequently, the information processing device 200 performs a physical
header parameter decision process (402), The physical header parameter decision
process will be described in detail with reference to FIG. 10,
25 10085}
Subsequently, a physical header parameter sharing process is performed
belween ihe information processing devices 301) and 200 (403). That is, a process
of sharing physical header parameters decided through Ihe physical header parameter
decision process between the informal ion processing devices 300 and 200 is
30 performed (401).
100X6S
27/142
Subsequently, Ibe inJorniittiojri processing device 200 performs a
transmission and recepLion process (405),
|O0S7|
The inlbrmalion processing device 100 performs a use physical header
Fl decision process (404). The use physical header decision process will be deseiibcd
indeiaii witnrcferen.ee lo FIG. \6. Subsequently, the information processing device
100 performs Ihe transmission and reception process (406),
jOOKSj
[Example of format of Presentation-layer Piolocol Dabi UniE (PPDU)]
10 FKl 7 is a diagram showing an example of the formal of a PPDU exchanged
between the devices iududed in the communication system 10 according to the first
embodiment of the present technology,
[0089]
The PPDU is configured to include Preamble 30L SIGNAL 302, Extension
15 303, Service 304, MAC! Protocol Data Unit (MPDU) 305, and liamc Check
Sequence (FCS) 306,
[0090]
The Preamble 301 indicates a portion corresponding to an IEEE 802.11
legacy Short Training Field (L-STF) or legacy L^mg Training Field (L-LTF) shown
21) inc of FIG. 7. The Preamble 10! is assumed to have a format compatible with this
Held.
|0091]
The STOMAL 302 indicates an TREE R02,11 Legacy SIGNAL (L-SIG) or
High Throughput SIGNAL (HT-SKi) field shown hi c of 1TG 1. HT Mixed Mode
25 Format oHFFF H02.!in is shown as an example in c of FIG. 7, The HT-SICJ may
he replaced with a Very High Throughput M1GNAL-A (Vlli-SIG-A) field in IEEE
R02.Mac and with High Efficiency SIGNAL (HE-SIG) Held in IEEF 802.1 lax.
J0092]
Tn accordance whh a format, additional fields (HT-STR TTT-LTF, VHT-STF,
30 VIIT-LTR and VOT-SIG-R) arc attaclicd subsequently in some eases.
[0093|
2K/142
Here. hi the first embodiment of iJie present technology. "Link Strength
Category fiekP is newly prepared in a par) of the field of the SIGNAL 302 which is -J
PLCP header of the physical bender. That isn "Link SLiengLh Category Held" is
newly set up in a portion EreaEcd a?» being reserved in the SIGNAL 302 of the PLC'P
5 heeler, Each information processing; device (other lhai> a legacy device) changes
"Link Strength Category Held" according to the quality of a Sink with a designation
at the lime oflrrinsniission.
|0094l
An example in which } is stored in "Link Strength Category field" is shown
10 in a of FIG 1. An example hi which G is stored in "Link Strength Category field" is
shown in b of KG. 7. In this way, Ihe examples in which the value (0 or 1) of two
stages is stored in "Link Strength Category Held" aie shown in a andb of FIG 7, but
a value of 3 or more stages may be stored.
[0095]
!,ri In this way, in the Jirst embodiment of the present technology, "Link
Strength Category field" is set up a portion treated as being reserved in the SIGNAL
^02. Thus: it is possible to realize a specific function in the fii-st embodiment of the
present teclinology without interfering with reception of the legacy device.
[0096]
20 In the first embodiment olr the present technology, a physical header of Link
Strength Category iietd-0 is referred to as "long-distance physical header." Further,
a physical header of Link Strength Category ficld=i is referred to as "short-distance
physical header," A physical header transmitted from a legacy device is assumed to
be treated as a "long-distance physical header/'
25 [0097]
An information processing device (other than a legacy device) receiving a
packet including Link Strength Category field changes a deieclion threshold to be
applied according to content (0 or ]} of Link Strength Category field.
[0098]
?A) [Lxamplc of connection process j
FTG. R is a sequence chart showing an example o!" a connection process
yf^BfiNwooi
29/ 142
between ihe devices included in I he communication system !C) accoulmy. to the first
embodiment of the present technology.
[0099f
MG. S shows FI processing example until collection between llie
5 in forma lion processing devices 100 and 200 is established. The same also applies
to a relation between the information processing devices 102 and 201.
[0100]
When connection is attempted, link quality between the information
processing devices 100 and 200 is unknown. For this reason, to reliably perform
10 connection, the information processing device !(K) uses the same preamble detection
tlucshold and physical header as those of the legacy device without performing
adjitslmenl of the threshold.
jMOll
That is, the information processing device 100 sets the same value as lhat of
15 a legacy operation (an operation of the legacy device) as the preamble detection
threshold (411). The information processing device 100 sets the same formal as
lhat of a legacy operation (an operation of Ihe legacy device) as the format of the
physical header (412),
[0102]
20 Ine Information processing device 200 sets the same format as that of a
legacy operation (an operation of the legacy device) as Lhe Ibrmat ^l' the physical
header (413).
[0103]
Subsequently, scanning is performed (414), Authentication is peribimed
25 (415), Association is perlirrmed (416), and 4-way Handshake is performed (417).
101041
When [he connection is established in this way, she control unit of the
information processing device 200 generates a list (setting information list) of the
setting information used by each information processing device (for example, the
30 information processing devices (.subordinate terminals) connected to the information
processing device 2011). The setting inlormalion list is a list Lhat is formed by a
SP 3 oW S11W0U1
m-'H2
combination o( each detection threshold of Ihe physical header and an application
level (application condition) of the physical header used by each information
processing device. The setting information list wilt be described in detail with
reference to l''KJ. 9.
5 [0105]
in the embodiment of (he present technology.. a pair of She detection
threshold of the physical header and the application level of the physical header is
referred to as a physical header parameter,
[0106]
10 The information processing device 200 updates content of information
already generated in information included in (he setting information list,
[0107]
| Example ofcuftlcnt of setting infonnaUon list]
I1G. 9 is a diagram schematically showing an example of content of a
15 setting information list 161 stored in the memory (corresponding to the memory 160
shown in HG. 5) of an informaiion processing device 200 according to the first
embodiment of the present technology.
]010K]
In the setting information list 361, an index 362, a detection threshold 163,
20 and an application level 164 arc stored in association (herewith.
[0109]
A value (0 or 1) indicating favor near is stored in the index 162.
[0110]
TUc detection threshold of the physical header decided through the physical
25 header parameter decision process is stored in the detection ttircshoJd 163, The
physical header parameter decision process is shown in FIG. 10_
[0111]
The application level of the physical header decided through the physical
header parameter decision process is stored in the application level 164.
{}[> |0112|
[Operation example of physical header paiarneJer decision process]
>SP3f)S5IlWOUl
^1/142
FIG. 10 is a flowchart showing an example of a processing ordei of a
physical header parameter decision process by the information processing device 21)0
according lo Ihe first embodiment of the present lechnotogy
|01I3|
5 First, the control unit of the information processing device 200 pciforms
tentative decision of the physical bender parameter ustdby (be subordinate terminals
in a self-basic service se! (BSS) and the sclf-dcvicc. i he control unit of the
information processing device 200 tentatively decides a detection threshold PDncar
of the short-distance physical header and a detection threshold PD far of the iong-
10 distance physical header.
j4)M4j
Here, since (here is no physical header of the application condition below
the detection threshold PD far of the long-distance physical header, a setting value
PD default for the legacy device is tentatively set as the detection threshold.
in [0I15J
The setting value PDdefanlt lor the legacy device is a value indicating a
reference level of the preamble detection used by the legacy device, hi the IEEF.
802, H standard, as a standard value, a value such as -82 dRm every 20 MHz
bandwidth is referred to. As the setting value PD_ default for the legacy device, a
20 value other than -82 dBm niay be used.
[0116]
Subsequently, (he control unit of the information processing device 200
decides application levels T near and L far of the physical headers based on the
detection threshold I'D near of the short-distance physical header and the detection
£5 threshold PD far of the long-distance physical header. Specifically, the control unit
of the information processing device 200 decides Ihp application levels I.near and
L far of the physical headers so that the following Expressions 1 and 2 are satisfied.
Here: Repressions 1 and 2 arc descriptions in which calculation in logarithm (dli) is
assumed.
30 l,_near>PD ncar+0 near ... Expression I
E_far — — ra ... Expression 2
sP'^siinvynoi
^2/142
|0117|
Here, The application Jevcis L near and L lar ol (he physical headers are
thresholds used to select physical headers (a kmg-dislan.ee physical header and a
short-distance physics! header) to be ased based on and connnun icy lion quality wish
•a deslinalion device. Fur example, when the information processing device 300
performs transmission, the applscaiion levels L_near and T,_!kr n! the physical
headei\s are used as ihi-esholds at the lime of selection of the physical headers to be
used as the eo in muni cat ion quality with the destination device.
[0118]
in Expression I, O near is an oJTset amount of a margin for a preamble
detection error by a variation in a reception tcveL For example, a valise ot about 10
dBm (o 20 dBm can be LEScd as O near. Further, a value other than 10 dBm to 20
d!3m may be used as O near,
[0119]
As indicated in lixpression 2, I. fai is set to the infinitesimal since there is
no physical header of the application condition below L far.
[0120]
Subsequently; the control unit of the information processing device 200
perfoims packet monitoring (step S70I). Then, the control unit of the information
processing device 200 acquires information regarding communication quality with
each subordinate information processing device in the scif-BSS and information
regarding communication quality of packels from other BSSs (OBSSs) (step S70!).
[0121]
Here, an example in which correlation output strength of the TLCF
preamble is used as an index of the coinmunication quality will be described. The
correlation output strength is not a correlator output in which power is normalized,
but is assumed lo indicate an absolute level obtained by multiplying a correlator
output by a received signal strength indicator (RSSI). That is: the correlation output
shenglh is a correlafoi outpLEt corrected to an antenna input conversion. When there
is a reception liistcjy at a relatively close tune, a record of the correlation output
strength at thai lime may he properly used. At the time of monitoring, the detection
33/142
threshold may be temporarily lowered so thai a more reliable sample is collected
[0122J
Here, a relation between the RSSl and a correlation oiHpul strength COL
(Correlator Output Level) can be simply indicated by the following expression,
5 correlation output slrenglli COL= RKS1 * normalized correlator output
[0123]
An example of the configuration of a correlator is shown hi FIG, 11,
|0124]
[Example of con figuration of cot relator]
JO FECI tl is a diagram showing an example of the configuration of a correlator
included in the informaiion processing device 200 according to the first embodiment
of tlic present technology. FIG 11 shows an example al' me configuration of a
general correlator serving as a reference. Here, an operator (&) described in FIG. 11
indicates complex conjugate calculation,
15 T0125]
Here, for the correlator, in general, there are largely two configurations
according to the characteristics of the preamble. For example, mere are two
configurations, a configuration of autocorrelation detection for generally detecting a
signal with certain periodicity and a configuration o J \;ross-correlation detection lor
2U detecting correlation with a decided pattern. An example of t he configuration of t he
autocorrelation detection is shown in a of FIG 31 and an example of the
configuration of t he cross-con elation detection is shown in b of FIG 11,
[0126]
In 1'IG 10. the control unit of the information processing device 200
2fi classifies information regarding the communication quality according to "Link
Strength Category field" in Ihe physical header used at the time of reception (step
S702),
[0127]
For example, (he control unit of Ehe information processing device 200 sots
yo a minimum correlation output strength to COL_ self_far in a packet in which the BSS
identifier (RSSID) h; the scif-USS and a physical header is a long-dislance physical
S>': 1301
Subsequently, the control unit of the information processing device 200
15 decides (he detection threshold PD near of the short-distance physical headci and the
detection threshold PDJai of the long-distance physical header (step S703), That
is, the control unit of the information processing device 200 correcls ihe tentatively
decided detection threshold PD near of Ihe .short-distance physical header and the
tentatively decided detection threshold PL) tar of the long-distEince physical header
20 so (hat relations of the following Expressions 3 k> 5 are eslablished (step S703).
PDneai > COL othernear . h L Expression 3
PDjar < COL_seHlfar ... Expression 4
PD_far> COl. other far ... Expression 5
ipmj
25 When there is no FD_far for which Expressions 4 and 5 are compatible,
PDjar is decided so that Expression 4 is preferentially established.
[03J2]
When these detection thresholds are decided (updated), the control imU of
the information processing device 200 corrects the application levels !,_near and
30 L far of the physical headers based on the above-described Expressions 1 and 2 (step
S703),
15/142
J0I33]
In this way, lbs detection threshold PD near of the short-distance physical
header, (he detection threshold PDfar of (lie long-distance physical header, and the
application levels Lnear and l,_far of the physical headers aje decided. The
5 conlrol unit of the information processing device 200 stores the values decided in Ibis
way in the setting information list 161 (shown in TIG. 9) and refers to the subsequent
values for use for itself Specifically, the control unii of the information processing
device 200 stores PD far in the dejection threshold I (S3 corresponding to "0,% of the
index 162 and stores I.Jar in the application level 1M corresponding to "0" of the
!0 index 162. The control unit of the information processing device 200 stores
PD near in the detection threshold 163 cones ponding to " 1 " of the index 162 and
stores I .near in the application level 164 corresponding to " 1 " of the index 162.
[01341
Here, the monitoring of the nearby packets -and the updating of the setting
|[j values dcsciibcd above may be per formed periodically or apenodically. For
example, the monitoring and the updating may be performed periodically every
given time or may be performed whenever connection of a new subordinate terminal
starts.
[0135]
20 [iixampic of earner sense detection rangej
FIGS. 12 and 13 arc diagrams showing system configuration examples of
the communication system 10 according to the first embodiment of the present
technology.
(01361
25 FTGSr 12 and J 3 show examples of Ihe carrier sense detection ranges of the
information processing devices set based on the detection threshold PD near of the
short -distance physical header and the detection threshold PD_far of the longdistance
physical header decided by the information processing device 200.
[0137]
30 In I'IG. 12, carrier sense detection ranges 31 to 34 of the information
processing devices 100 and 102 are schema! ically indicated by doited circles. In
36.;I42
KKi. 1.1. carrier sense defection ranges 41 In 44 of She hihiimabon processing devices
200 and 201 arc schematically indicated by dotted circles.
[onsj
Specifically, in FIG 12. Ihe carrier sense detection range 31 indicates the
5 earner sense detection range of the information processing device 100 sel based on
the detection threshold PDJUr of the long-distance physical header. The carrier
sense detection range 33 indicates the carrier sense detection range ol the
information processing device 100 sel based on Lite detection threshold PD near of
the short-distance physical header.
10 [0139]
In JIG. 12, the carrier sense detection range 32 indicates the carrier sense
detection range of Ihe information processing device 102 set based on the detection
threshold PD far of the long-distance physical header. The carrier sense detection
range 34 indicates the canity sense detection range of the information processing
15 device 102 set hased on the detection threshold PD near of the short-distance
physical header.
[0140]
In FIG. 33, the carrier sense detection range 41 indicates the carrier sense
detection range of the information processing device 200 sel based on the detection
20 threshold PD_far of the long-distance physical header. The carrier sense detection
range 43 indicates Ihe carrier sense detection range of Ihe inlbrmaJion processing
device 200 set based on the delectinn threshold PD near of the short-distance
physical header,
|014l|
25 In FIG. 13, (he carrier sense detection range 42 indicates the carrier sense
detection range of the information processing device 201 set based on the detection
threshold PDfar oT Ihe longdistance physical header. The canier sense detection
range 44 indicates the carrier sense detection range of the information processing
device 201 set based on (he detection threshold PDnear of the short-distance
30 physical header.
[0142]
The examples in which the classification of two values of the short distance
and the long distance is performed have been described -above, but classification of
tlarcc 01 mote values (N values) may be performed. For example, detection
thresholds of Lhe physical headers arc set to PL) 0. PD 1, ..., and PU N and the
Ti application levels ai the PLCPs aie set to I._0, T._1, ..., jmd I._N in ordei for the
long distance. Further, the detection thresholds of the physical headers and offset
amounts between the application levels of the physical headers are sel lo O_0; 0 _ 1 :
..., and O N. hi tills case, values are decided so that the following relation
expressions (Repressions 6 to 9} are satisfied. Here: Expressions 6 to 9 arc
1U description in which calculation in logarithm (dB) is assumed.
PD_n > COT . o t h e r n ... Expression 6
(where n = 0 to N)
PD_0 PD_n+() n ,.. Expression 8
15 (where i i - 1 toN)
L 0 = - t« ... Expression 9
11)143]
In the case of the classification of three or more values, PDO is decided so
that Expression 7 is preferentially established when there is JUS PDO for which
20 Expressions 6 and 7 are compatible.
[0144|
[Example of beacon frame format |
FK1 14 is a diagram showing an example of a beacon Iratne format
exchanged between the devices included in the communication system 10 according
2f> lo the fu-st embodiment of the present technology. Here, an example of a beacon
frame transmitted from the information processing device 200 to another information
processing device will be described.
[0145]
FIG. J 4 shows an example in which an clement such as "Multi Detect
30 Parameter" 311 is newly added to a payload 310r In "Multi Detect Parameter" 311:
an index (0 or 1) indicating far or near is stored in "PLCP Header indexes'' 313 and
SP^MlWOUl
18/142
116 The deleeLion Ihrcshold PD far of me long-dii;[anee physical header and She
detection threshold PD near of the short-distance physical header are stored in
•""Preamble Detection Thresholds" 314 and 317, The application levels of ihe
physical headers arc stored in "Apply Levels" 315 and 3 [R.
5 [0146]
Generated combinations are set up as combinations of 'TT CP Header
Index/' "Preamble Detection Threshold," and "Apply Level." lor example, as
shown in FIG. 9, a ease in which two pairs of pieces of information (two pairs of "0"
and " 1 " of the index 162) are stored in the setting information list 161 will be
10 assumed. In this case: two paiis of combinations are set up as combinations of
"PI X:P Header Index," "Preamble Detection Threshold/' and "Apply Level/'
[0147]
Specifically, the control uniloi'the inlbrnjation processing device 200 stores
eacii piece of content of the setting information list 361 shown in HG. 9 in the
15 beacon frame to transmit the content. That is, Ibe control unit of Ibe information
processing device 200 stores information stored in association with "0" of the index
162 in a first combination (l'PLCP Header Index" 313 to "Apply Level17 315). The
control unit of the information processing device 200 stores information stored in
association with " 1 " of the index 162 in a subsequent combination (l unit of the infomiahon
processing device 200 transmits the information regarding the packet detection
condition (for example, a packet detection Threshold (the detection threshold 163
shown in FIG, 9) and a selection condilion (the application level 164 shown in UG.
9} for selecting the packet detection threshold) to nearby information processing
no devices to inlbrm the nearby infonnation processing devices of the information.
'Ibe selection condition can be ascertained as a selection condition for selecling one
TiPrtoHMiWOUl
WI42
physical header hum a plurality of physical header candidates and a sdeelion
condition of (he physical header corresponding to each paekel deiedion eondiJioii.
[0149]
[Communication example of physical bender parameter sharing piocessj
5 FIG 15 is a sequence chart showing an example of a physical header
parameter sharing process between (he devices included in the communication
system 10 according to the lust embodiment of the present technology,
[0I50J
i'lG. 15 shows an example of a sharing process in which the control unit 150
50 of the information processing device 100 receives a beacon transmit tod from the
information processing device 200 and shares the physical header parameters. The
same also applies to a case in which other information processing devices receive a
beacon transmitted from the information processing device 200. For examplc: the
control unit of the information processing device 200 can notify the subordinate
15 terminal of me physical header parameters using the beacon frame shown in FICi. 3 4.
10151J
First, the control unit of the information processing device 200 stores a set
of the detection threshold of each physical header.. and the application level of each
physical header and the index of each physical header in the beacon (421). Then;
20 the control unit of the information processing device 200 transmits the beacon to the
subordinate information processing devices (422 and 423),
[0152 J
When the beacon from the control unit of the information processing device
200 is received (423), the control unit 150 of the information processing device 100
2b acquires and retains the content oP'Multi Detect Parameter" 311 (shown in FIG 14)
included in me beacon (424).
[0153]
When the content of "Multi Detect Parameter" 311 included in the
subsequent beacon is changed, the control unit 150 of the information processing
'Mi device 100 adopts and retains new inlbrmatiou after the change in the content. That
is, [he old information is updated.
ttrttiWHIWOOl
40/542
[0154]
When the content of '"Muiti Detect Para meter" 331 is already acquired and
retained* the control vjiiit 150 of ihe information processing device 100 upstates the
retained content teed (in a newly received beacon (424).
!i [01551
The example in which the control unit of the information processing device
200 notifies each information processing device of (he physical header parameters
using tlic beacon lias been described FKL 15h but the physical header parameters may
be notified of using a signal other than the beacon. Fur example, ihe control unit of
10 the information processing device 200 may perform the notification using a unicast
data frame or management frame to a subordinate terminal using determination by
the self-device oiL an information acquisition request from the subordinate terminal as
a trigger, in this case, Ihe control unit 130 of the information processing device 100
similarly acquires and retains the content of "MuHi Detect Parameter" included m the
15 unicast frame.
10156]
[Operation example of use physical header decision process]
FIG 16 is a flowchart showing an example of a processing order of a use
physical header decision process (transmission physical header selection process) by
20 the information processing device 100 according to the fii'st embodiment of Ibe
present technology.
JO 157]
Fh-sl, the control unit 150 of the in formation processing device 100 monitors
packets received from designations connected to the self-device and acquires the
25 RSSI of each designation (step S711), The RSSI (monitoring result) acquired hthis way is set to RSSI peer,
10158]
When measured values of the packets received from the destinations
connected to the sell-device are retained, the control unit 150 of the information
30 processing device 100 may read the measured value to acquire the RSS! of each
destination (step S711).
SP:toH;ll!WO01
TTere, in the case of the informalion processing device (for example, the
information processing device 3 00) connected to the master station (foe example, the
information processing device 200), only the master station is basically sef as lhc
5 destination. \n this case, the receplion level of a pluvious beacon may he used as a
monitoring result,
[03 60]
Subsequently, the control unit 150 of the information processing device 100
compares the acquired RSSi peer to (he application level E._ncar of the physical
10 header and decides the index of the physical header to be used for transmission by
the self-device based on (be comparison result (step S712). The implication level
L near of the physical header is included in the beacon transmitted from. the
information processing device 200.
[0161 j
15 For example, when the acquired RSSI_peer is greater than the application
level Lnear of the physical header, the control unil 150 of Ihe information
processing device 100 decides 1 (for Ihe short distance) as the index of the physical
header to be used for transmission by the sell-device (step S712). Conversely,
when (he acquired RSSi peer is equal to or less than the application level L near of
20 the physical header, the control unit 150 of the information processing device 100
decides 0 (for the long distance) ELS me index of the physical header to be used for
transmission by the self-device (step S712),
[0162]
When the tudex of the physical header (o be used for transmission by the
2fi self-device is already decided and a new index is decided, the already decided index
is updated to the new index (step S7I2).
|0163j
in FIG. 16, Ihe example in which the use physical header is decided based
on ihe classification of two values of the short distance and the long distance has
30 been described, bul Ihe use physical header may be decided based on classification of
three or more values (N values). For example, the application levels of the FLCPs
.sP'^Somvooi
42/142
are set to L 0, T _ 1 , . .. L_N in order for ihc long distance. Ill fills case, n satisfying
I he iotlowing relation expression (lixprcssion 10) is selected as the index of the
physical header to he used for transmission. Here, Expression 10 h description in
which calculation in logarithm (dR) is assumed.
5 L_n < RSSI_pccr •-- L._n H ... Expression 10
(where n -0 to N)
|0I64|
The operation example of (he stave station side its the case o! uplink
transmission from the slave station side to ihe master station side has been described
E0 with reference to FIG, 16. In the case of downlink transmission, however, the same
operation may he performed on the master station side,
]0165]
The example in which Lhe K.SSI is used hfls been described in I'iG 16.
However, ihe correlation output strength COT. may be used instead of the I? SSI,
la 10166]
[Operation example of transmission and reception process]
I1G. 17 is a flowchart showing an example of a processing order of a
transmission and reception process by the information processing device 100
according to the first embodiment of the present technology. In FIG. \1, the
20 information pn>eessing device 100 will be described, but (he same can also apply to
the other information processing devices (lor example, the information processing
device 200). That is: the transmission and reception process is lhe same on both of
(he master station side and (he terminal side.
[0367]
2fi lhe control unit 150 of the information processing device 300 performs a
packet detection determination process for a time other Ihau during transmission and
during reception (step S730), The packet detection determination process will be
described in detail with reference to I-1G, 18.
|0!68j
30 Subsequently, the control unit 150 of lhe inhumation processing device 100
determines whether a determination result obtained in the packet detection
SPrir>ft5NWO0i
4.1/142
determination piocess is ^'detection'h (siep S72I). When the determination result
obtained in the packet detection determination process is "detection" (step S721), (he
control unit 350 of the information processing device 100 performs a reception
process ol' continuing reception (step S722). 'Ihen. after the reception is completed.
ft (lie control unit 150 of the information processing; device 100 returns to a waiting
state, When Jhe received packet is destined for the self-device and an instant reply
is requested, the control unil 3 50 of the information processing device 100 adds and
transmits a physical header including (he same "Link Strength Category" fieid as a
target packet. That is, portions in the SIGNAL field in "which the information
10 regarding the detection thresholds is stored are set to be the same, and information
decided in the sell-device is stored in other portions (for example. Modulation and
Coding Scheme (MCS) and length).
[0169]
When the determination result obtained in the pack el detection
15 determination process is not "detection" (step S721), the control unit 150 of the
information processing device 100 determines whether the determination result
obtained in the packet detection determination process is l'non-deteeEiorr (step S723).
When the determination result obtained in the packet detection determination process
is "non-detection" (step S723), the control unit 150 of the information processing
20 device 100 determines whether there is a packet to be transmitted (step S724).
101701
When there is a packet to be transmitted, the control unit 150 of the
information processing device 100 determines whether a determination state oi^ the
non-deteclion continues for an inter frame space (US) and a backoff time or more as
2ft dclined in the procedure of Ca3~rier Sense Multiple Access with Collision Avoidance
(CSMA/CA) (step S725).
1017IJ
When the determination state nl' the non-detection continues for the TFS and
the backoff time or more (step S725), the conhol unit 150 of (he information
30 processing device 100 performs a transmission process since transmission can lie
performed (step S726). In the transmission process, for example, me control unit
JiPn&aoiiwoui
44/142
ISO ol the information processing device 100 usee ihe physical header wtlh the
format of the PFDU shown in FTC'S. 7 far [he transmission bused on the index of the
physical header iSeeided in the transmission physical header decision process shown
inl IG. 16.
5 [0172]
Specifically, when 3 (for Ihe short distance) is decided as the index it! the
transmission physical header decision process, the control unit 150 of Ihe
information processing device 100 stores 1 in Ihe "Link Strength Category Held" li>
perform the transmission (step S726), Conversely, when 0 (for the long distance) is
10 decided as the index in She transmission physical header decision process, Ihe control
unit \50 of the information processing device 100 stores 0 in "Link Strength
Category field" to perforin Ehc transmission (step S726).
[0E73J
lor example, the coniro! unit 150 of the information processing device 100
15 selects a modulation and communication path coding scheme by which a destination
device can perform reception al a high probability according to the detection
Threshold corresponding to (he decided physical header for the purpose of modulation
used in a data portion, and performs Ehc transmission using the selected scheme.
lor example, the control unit 151) of the information processing device 100 may
20 select a modulation and communication path coding scheme (MCS (Modulation and
Coding Scheme)) by which a destination device can perform reception at a high
probability according to the detection threshold vxirresponding to die decided
physical header and perform the transmission. When there is no packet to be
transmitted, the stale returns to the wailing state.
an | o 1741
When Ihe determination result obtained in the packet detection
determination process is uof "nmi-detection" (when the determination result is "onlyenergy
detection") (step S723), the conlnd unit 150 of the information processing
device 100 basically treats a wireless state as a busy state and suppresses
,10 transmission from the self-device (step S727), Here, the control unit 150 of the
information processing device 100 performs the transmission of the reply packet
SPSSSSUWOU]
4VI42
(slcp S729) onlv when the packet define*! ibr Ihe self-device is received and a replv
immediately after the reception is requeued (step S72H).
[0175]
FICI IK is a flowchart showing a packet detection determination process (the
5 processing order of step S7i0 .shown in 1IG 17) in The transmission and reception
process by Ihe information processing device 100 according to the first embodiment
of the present technology.
[0176]
1'irst, the control unit 150 of the information processing device 100
10 performs measurement of Ihe RSSlon a signal inpul via the antenna HE and regains
me RSS1 obtained through the measurement {step S73 ]).
[0177]
Subsequently, the control unit 150 of the information processing device 100
performs correlation calculation of a Preamble pattern to obtain a correlator output
15 (step S732). The correlator output is the abovtj-described correlation output
strength COL That is, the correlator output is not a normalized correlator output
level, but is a correlator output converted by reelecting reception power,
[0I7KJ
Subsequently, the control unit 150 of the information processing device 100
20 compares the value of llic correlator output to a tentative detection threshold to
determine whether the value of the correlator output is greater than the tentative
detection threshold {step S733). Here, the tentative detection is detection performed
to determine whether to read the SIGNAL field before the detection determination.
The tentative detection value is set to a value that is eqtial to or less than both of
25 PL) near and PD far described above. The tentative detection threshold may he set
Eo PD_default descinbed above.
[0179]
When the value of the correlator output is greater than the tentative
detection threshold (step S7^3): (he control unit 150 of the information processing
,10 device 100 determines tliat the state is the tentative detection state (step S734),
Subsequently, the control unit 150 of the information processing device 100 reads
ypti5tomvouj
46/142
"Link .Slrenglh Category field" in the subsequent. SIGNAL Held of (he physical
header. As described above. information indicating the detection threshold to be
applied is stored in "T.ink Strength Category Jield."
|01K(i[
5 Here, the control unit 151) of the information processing device 100 i-etainw
the content of "Preamble Detection Threshold71 shared in the physical header
parameter slsaring process shown in MG 15. The control unit 150 of the
information processing device 100 decides the detection threshold Us be applied (an
application detection threshold) based on the content of "Preamble Detection
10 Threshold" and the content of "Link Strength Category Held" (step S735).
[0I81J
For example, in the ease of Link. Strength Caiegory-0, the control unit I 50
of Ibe inlbrmalion processing device 100 decides PDfar as the application detection
threshold. Conversely, in the case of Link Strength Catcgory=l, the control unit
J5 ISO ol' the inlbmialion processing device 100 decides PDnear as the application
detection threshold. When the transmission and reception process is performed, the
control unit 150 of the information processing device 100 uses the decided
application detection threshold (PDIar or PD near).
[0182]
20 Subsequently, the control unit 150 of the information processing device 100
compares the measured and retained RSSI to the decided application detection
threshold to determine whether the RSSI is greater than the application detection
threshold (PD far or PD_near) (step S736), When the KSSl is greater than the
application detection threshold (step S736), the control unit J 50 of the information
25 processing device 100 sets the packet detection determination result as ^detection'1
(step S737),
T0IS3]
Here, the packet detection determination result may he set to "detection5*
only when another condition is satisfied. For example, an error detection code
30 including "Link Strength Category field" as a target may be set up in a reserved field
remaining in the SIGNAL licld. A condition ihat validity of the content of "Link
tfP35a51lWOfJl
47/142
Strength Category field" be confirmed by the error deletion code including :"l.mk
Strength Category field1' a.a the target may be set as an additional de-term tnation
condition.
J01S41
5 Here, Ihe error detection code including %nworji
50/142
information processing devices 3 00 to J 03, 200h and 20] shown in RG I and the
like. Therefore, llic same icferencc numerals as Those of the fust embodiment of
the present technology are given In common portions to those of the first
embodiment of the present technology. and the description thereof will be partially
5 omitted.
[0198]
Sumi; of the processes and the formats in the second embodiment of fiho
present technology are common to those of the first embodiment of the present
technology- Therefore, the same reference numerals as those of the first
10 embodiment of the present technology arc given to common portions to those of the
first embodiment of the present tcclinology, and the description thereof will be
pailia I ly omitted.
[0199]
[Operation example of transmission and reception process]
15 I'lG 19 is a flowchart showing an example of a processing order of ibe
transmission and reception process by the information processing device 300
according to the second embodiment of the present technology. ]n FiG 19, a part of
the transmission and reception process shown in FIG. 17 is modified. Therefore,
the same reference numerals as those of FIG 17 arc given to common portions to the
20 transmission and reception process shown in FIG 17, and the description thereof will
be partially omitted.
[0200]
When the determination result obtained in the packet detection
determination process is :Lonly-encrgy detection'* {step S723). the control unit 150 of
2d the information processing device 100 basically treats a wireless slate as a busy state
and suppresses transmission from the self-device (step S727), When tSie wireless
state ts treated as the busy state in Ibis way, all of the transmission is suppressed in
the second embodiment of ihc present technology,
[0201]
30 In this way, in Ibe second embodiment of the present technology, all of the
transmission is suppressed when ibe determination result obtained in the packet
ftP:i:iKniiwoui
51/142
detection determination process is "'only-energy detection." Thus, it is possible In
further improve safety of (he operation of the transmission and reception process.
[0202]
*"-3. J hiid embodiment^
5 In the iirsf embodiment of the present technology, (he example in wliich
I .ink Strength Category field is set up in the SIGNAL Held of the JFFF 802.11
standard has been described.
[0203]
In a third embodiment of the present technology, an example in which Link
10 Shenglh Category field is set up in a service field of the llilili 802.11 standard will
he described. The configurations of information processing devices in the third
embodiment of the present technology arc substantially the same as the
con figurations of the information processing devices 100 to 103, 200, arid 201 shown
in FIG 1 and the like. Therefore, the same reference numerals as those of the first
15 embodiment of the present technology arc given to common portions to those of the
first embodiment of the present technology, and Hie description thereof will be
partially omitted.
! 02041
Some of (he processes and the formats in the third embodiment of the
20 present technology arc common to those of the first embodiment of Jhe present
technology. Therefore, the same reference numerals as those of the firs I
embodiment of the present technology arc given to common portions to those of the
first embodiment of the present technology, and the description thereof will be
partially omitted.
25 [0205]
[Example of format of PFDU]
FIG 20 is a diagram showing an example of the format of a PPDU
exchanged between the devices included in the communication system 10 according
to the third embodiment o! the present technology.
30 |0206|
Here, the example shown in FIG 20 is the same as the example shown in
yP35W51lVVO01
S2--142
K!(i. 7 except thai I.ink Strength Category Eield is sel up in a Service liekl rather lb an
in the SIGNAL field. Accordingly.. the same reference numerals as Lhose of I'IG. 7
are given lo common portions to those of FIG 7, and Ihe description (hereof will be
partially omitted.
ii [0207]
Hie PPDU is configured lo include Preamble 301, SIGNAL 307. Kx tension
303, Service 308. MPDU 305: and PCS 306,
[0208]
Here, in the third embodiment of the present technology, "Link Strength
10 Category field" is newly prepared in a part of Pie Held of Service 308 of Hie physical
header. That is, "Link Strength Category Held" is newly set up in a portion treated
as being reserved in Service 308 of the physical header, Then, each information
processing device (other tlian a legacy device) changes "Link Strength Category
field17 according to the quality of a link with a destination at the time of transmission,
15 [0209]
in this way, in the third embodiment of the present technology, '"Link
Strength Category field" is set up in the portion treated as being reserved in Service
30X. Thus, as in the first embodiment of the present technology, it is possible to
realize the specific function without interfering with reception of the legacy device.
20 [02S0J
[Operation example of transmission and reception process]
By replacing "SIGNAL field" with "Service Held" in ihe transmission and
reception process (step S73.S) shown in FIG. 18 and performing the same process as
Ihe transmission and reception process shown in KiGS. 17 and 18, it is possible to
25 realize the third embodiment oEThc present technology.
[0211]
Here, the error detection code including "Link Strength Categoiy field'1 as
the target may be inserted into a reserved Held remaining in the service field. A
condition that validity of the content of "Link Strength Categoiy field" be confirmed
30 by the error detection code including "Link Strength Category Held" LIS the target
may be set as an additional determination condition.
53/S42
S!»^JH:>1IWO0I
|0212|
In Ibis way: in ihe third embodiment of Ibe present technology, T .ink
Strength Category field is set up in ibe Service field of the IhKK R02J ] standard.
Thus, morc information can be stored than in the first embodiment of the present
5 technology. For example, even when Ibe modes <>! PJ.CP are sel with multiple
values, the information can be appropriately stored,
[0213]
<"4. Fourth embodiment-"
In the lirst !o third embodiments oT the present technology, Ibe examples in
10 which the detection thresholds of PLCP arc changed based on the content of the
fields of the physical header have been described,
[0214|
In a fourth embodiment of the present technology, an example in. which a
plurality of preamble sequences with dUferent detection thresholds are used on a
ITi transmission side and preamble correlation detectors applied by the RSSI are
switched on a reception side will be described, Thus, the reception side can receive
only a desired packet. The configurations of information processing devices in the
fourth embodiment of the present technology are substantially the same as the
conliguialions of the information processing devices 100 to HB: 2(H), and 201 shown
20 in 1'Ki. I and the like, Therelbre, the same reference numerals as those of Ihe Jirst
embodimen! of the present technology are given to common portions to those of the
first embodiment of the present technology, and the description thereof will be
partially omitted.
[0215]
25 Some of (he processes and Ibe formats in the fourth embodiment of the
present technology are common to those of the first embodiment of the present
technology. Therefore, the same reference numerals as those of the first
embodiment of the present technology arc given to common portions to those of the
firs] embodiment o!" the present technology, and ihe description thereof will be
'SO partially omitted.
[02 3 f. j
54/142
[Example of format of PPDU |
MG 2\ is a diagram showing an example of ihe format of a PPDIJ
exchanged between the devices included iii the communication system 10 according
Jo ihe fourth embodiment of the present technology,
5 [0217]
Here, the example shown in FIG 21 is the same as the example shown m
MG 7 except IhaE 1 .ink Strength Category field is nol se< up iti the SIGNAL l]eld: but
the plurality of Preamble sequences aie defined, Accordingly, the .same reference
numerals as those of FIG 7 are given to common poriitms to Ihosc of FIG 7, and the
10 description thereof will be partially omiUed,
[021K|
The PPDIJ is configured to include Preamble 3 II. SIGNAL 312, Extension
TO, Service 304, MPDU 305, and FCS 306.
102191
15 Here, in the fourth embodiment of the present technology, a sequence of a
plurality of Preambles 311 is deimed. lor example, as shown in a of 1IG 21: a
sequence such as "Preamble #1" is defined in Preamble 31L As shown in b of I'lG.
2 l : a sequence such as "Preamble //0'1 is defined. Then, each information
processing device (other than the legacy device) changes the sequence Lo be used
20 according to the quality of Ihc link with the destination at the lime ol" transmission.
11G. 23 shows an example in which two kinds of IVcamblcs arc prepared, hut tlucc
or more kinds of Preambles may be prepared.
10220]
In the fourth embodiment of the present technology, Ihe physical header IJI
2Ji which the sequence such as '"Preamble #(F is used in Preamble 311 is referred to as a
^long-distance physical header." The physical header in which the sequence such
as "Preamble #3" is used in Preamble 31J is referred lo as a "lshort-d is lance physical
header." The Preamble sequences are generated by different rules and have low
mutual correlation. Preamble sequence #0 is assumed to be the same sequence as
30 the Preamble used by the legacy device.
[0?21]
55/I42
F,;jch information processing device (other than the legacy device) receiving
the packet that includes such a physical header changes Hie eoiretator {and the
thresholds determined in detection) U> be applied according EO the magnitude of Ihe
RSSlol a signal.
r> ]0222]
Here, when the IEEE 802,11 standard is assumed, ^another Preamble" is
assumed to mcanthat at least otic of L-STF and T.-LTF is different.
[0223]
[Operation example of transmission and reeeplion process |
[0 FIG 22 is EL flowchart showing a packet detection determination process (the
processing order of step S730 shown in 1'IG 17) in the transmission and reception
process by the information processing device 100 according to (be fourth
embodiment of die present technology.
(0224|
15 First, the control unit 150 of the information processing device 100
performs measurement of the RSSi on a signal input via the antenna !4! and retains
the RSK1 obtained through die measurement (step S75 I).
[0225J
Subsequently, the control unit 150 of the information processing device 101)
20 compares Ihe measured RSS1 to ihe retained application levels (L_iar and 1 ._ncar) of
the physical headers and decides the index ol the physical header to be applied to
detection (step S752), 1'or example, as in the seleclion method of selecting the
transmis&ion physical header of the self-device, it is possible to decide the index of
the physical header to be applied io the detection,
25 |0226|
For example, when the measured RSS1 is compared to the value of L near
and the measured RSST is greater than T.near, the control unit 150 of the information
processing device 100 decides 1 (for the short distance) as the index of the physical
header to be used for Ihe correSation detection of the self-device. Conversely, when
afj the measured RSSI is equal to or less than. Fnear, Ihe control unit 150 of the
information processing device 100 decides 0 (for the long distance) as the index of
arassoiiwooi
5(1/142
the physical headei to be used lor die correlation detection of the self-device.
[0227J
In die decision procedure, it is assumed that there is no difference in
transmission power between the slave and master stations. However, when
5 information regarding a difference in the transmission power is retained in advance
despite the diHcrencc in the transmission power between the slave and master
stations, the determination can be performed after appropriate correction is applied
based on the retained information regarding the difference in the transmission power.
[022R]
10 Subsequently, the control unit 150 of the information processing device 100
performs correlation calcuhslion using the correlator corresponding to the preamble
sequence generated by the different rules, as described above, in the physical header
with the decided index (step S7.S3). Here, a correlator output is a correlation output
strength COL as in the tfrst embodiment of the present technology. That is, the
1 fi correlator ouipul is not a normalised correlator output level, but is a correlator output
converted by reflecting reception power.
[0229]
Subsequently, the control unit 150 of the information processing device 100
compares the correlator output of the selected corretalor to the detection threshold of
20 the physical header in the decided index, to determine whether the value of the
correlator output is greater than the detection threshold (step S754).
|"0230]
When the value of the correlator output is greater than the detection
threshold (step R754). the control unit 150 of the information processing device 100
25 sels the packet detection determination result as Selection" (step S755),
|0231]
When the value of the correlator output is equal to or less than the detection
threshold (step S754), the control unit 150 of the information processing device 100
compares the measured RSSl to the energy deled ton threshold liL) (step S756),
;i0 Then, the control unit 150 of the information processing device 100 determines
whether the RSSI is greater than (he energy deletion Lhrcshold \iD (step SV56).
f-ii';toB5iiwoni
57/142
f023?.]
When the RSS1 is greater than the energy detection threshold hO (step
S756). the control unit ISO of the information processing device HK) sets the packet
detection determination rcsnh lo "only-energy detection" (step S757).
5 [0233]
When the RSS1 is equal to or less than the energy detection threshold ED
(step S756), the control unit 150 of the information processing device 100 seLs She
packet defection determination result to "non-detection" (step S75H).
[0234|
10 Here, when the iHHli 802,11 standard is assumed, the detection threshold of
the I -STF portion can be set as the "detection threshold'1 in the fourth embodiment
of the present technology. However, instead of the detection threshold of the L-SIF
portion, the detection threshold of the T.I.Tii portion may be set or the detection
threshold common to both of the L-STF portion and the L-LTP portion may be set.
Ifi By independently changing the detection thresholds of the T.-S'l"[' portion and the ILTF
portion, both of the dejection thresholds may be designated as the physical
header parameters.
[023 Sj
<-5. Fifth eiribodimcrtt>
20 A fifth embodiment of the present technology is a modification example of
the fourth embodiment of the present technology* An example in which a master
station side selects a physical header which is used by a subordinate information
processing device will be described. An example in which a reception side operates
correlators of preamble sequences which arc candidates normally in parallel will be
2D described.
]0236]
The eon figurations of information processing devices in the fifth
embodiment of the present technology arc substantially the same as the
configurations of the information processing devices 100 to 103, 2GG> and 201 shown
SO in FTG I and the like. Therefore, the same reference numerals as those of the first
to fourth embodiments of the present technology arc given to common portions to
ttiM!*(r>iiwooi
SS/H2
those of The ilrsl to louiih embodiments of Ihc present technology. and the
descriphon thereof will bo partially omitted.
|0237]
Some o! the processes and die formats in the fifth embodiment of the
ft present technology arc common lo those of the iiist lo iburlh embodiments of the
present technology. Therefore, the same reference numerals as those of the ilrsl to
fourth embodiments of the present technology Eire given lo common portions to those
of the first to fourth embodiments of the present technology, and the description
thereof wilt be partially omitted.
10 ]023X[
[Example of beacon frame format]
b'JCi. 23 is a diagram showing an example of a beacon frame formal
exchanged between (lie devices included in a communication system 10 according to
the liflh embodiment of the present technology. Since FIG. 23 is a modi ii cat ion
i.ri example of FIG 14, Lbe same reference numerals as those of FIG 14 ai'c given to
common portions to those of FIG 14: and the description thereof will be partial ly
omitted.
[0239]
VK'L 23 shows an example in which an element such as "Mulii Detect
20 Assignment" 321 is newly added to Payload 320 along with "Mtilti Delect
Parameter'3] I.
J0240]
In "Muhi Detect Assignment1' 321, information for specifying the
subordinate information processing devices is stored in "Association ED" 323 and
25 325. Tn FIG. 23, the example in which Association ID is stored as the information
for specifying the information processing devices is shown, but other information
capable of specifying the information processing devices may be stored, For
example, MAC addresses may be stored.
[0241]
30 The index (0 or 1) of the physical header to be used by the information
processing devices is stored in "PLCP Header Index" 324 and 326. Such
spy^.r. 11 wont
54/142
combinahons are arranged and stored in regard to all of the subordinate inhumation
processing devices (olher than the legacy devices).
1024?]
The control unit of the information processing device 200 transmits a
fi beacon in which the information indicated in "Mulli Detect Parameter" 311 and
l'MuUi Detect Assignment'1321 is stored to nearby information processing devices fo
inform the nearby information processing devices of the beacon.
|0243]
[Communication example of physical header parameter sharing process]
10 FIG 24 is a sequence chart showing an example of a connection process
between Ihe devices included in the communication system 10 according to the fifth
embodiment of ilie present technology.
[0244]
Since FIG 24 is a modi Meat ion example of FIG !5: the description of
IT) common portions to those of TIG. 15 will be partially omitted. That is. FIG. 24
shows an example in which physical headci parameters are included in a beacon to
bo transmitted and information for designating Ihe physical header to be used by each
subordinate information processing device is also included in the beacon to be
transmitted.
211 f0245]
First. the control unit of the information processing device 200 stores a set
of the detection threshold of each physical header, and the application level of each
physical header and Ihe index of each physical header in "*Mu!ti Detect Parameter"
311 (shown in FLU 23) of ihe beacon (431).
25 [0246J
The control unit of the information processing device 200 stores the set of
the information for designating the physical header to be used by each subordinate
information processing device in ':MuHi Detect Assignment" 321 (shown in FIG 23)
of the beacon (432),
30 [0247]
Here, a case in which content of the '^•lulti Detect Assignment* Field is
SP3r.8!MlWnui
£0/142
skived will be described. Hie control unit ol'ibc in formation processing device 200
confirms whether a generaliou function and a correlation deEeclion function [or the
Preamble sequences designated by the Capability of each subordinate an formation
processing device arc supported.. and then stores only the corresponding Preamble
5 sequence. When each subordinate in formation processing device corresponding to
a specific function selects the physical header to be used, information regarding link
quality belween the master station and cacti subordinate stevc station is determined
to be used. Therefore, packets received from destinations connected to the selldevice
are monitored (or retained measured values are read) and the RSSI lor each
10 destination is acquired to be used, instead ol~ the RSSi, the above-described
correlation output strength COL may be used.
[0248]
Subsequently, the control unit of the information processing device 200
transmits the beacon to the subordinate information processing devices (433 and 434).
15 [0249J
When the beacon from the information processing device 200 is leecived
(434), the control -unit 150 of the information, processing device 100 acquires and
retains each piece of content included in the beacon (435), That is, the control unit
150 of the information processing device 100 acquires and retains Ibe content ol'
20 "Multi Detect Parameter" 311 and the content of lMulti Detect Assignment" 321
(shown in FIG 23) included in the beacon (435).
[0250J
The control unit 150 of the information processing device 100 uses the
corresponding physical header according to the index of tbe physical header
25 designated with the beacon by the master station ((he information processing device
200), That is, the control unit 150 of Ihe information processing device 100 docs
not perform the autonomous determination,
[0251]
| Operation example of transmission and reception process |
30 MG 25 is a flowchart showing a. packet detection determination process (the
processing order of step S730 shown in FIG, 17) in the transmission and reception
^iMr>8r>iiW0Q]
61/142
process by the informalion processing device 100 according Lo the fifth embodiment
of the present. technology.
10252|
TIG 25 shows an example in which each master station and each slave
5 station corresponding to the specific function operate all of the correlators of the
PLCP Preambles supported by the sell-device in parallel.
[0253]
First, the control unit 150 of ihe information processing device 100
performs measurement of the RSS1 on a signal input via the antenna 141 and retains
10 IheRSSl obtained tluouglUhe measurement (step S763).
10254]
Subsequently, the control unit 150 of Ihe information processing device 100
inputs an input signal lo each correlator and performs correlation calculation (step
S7u2)r Thai is, the control unit 150 of the information processing device 100
1ft calculates correlation between the preambles simultaneously m the correlators (step
S762).
[0255]
Here, as each detection threshold for determining the detection based on
each correlator output, the detection threshold of each physical header designated
20 Irom the master station is used in the physical header parameter sharing process.
The correlator output is the correlation output strength COT. as in the first
embodiment of the present technology. Thai is, (he correlator output is not a
normalized correlator output level, but is a correlator output converted by rellecting
reception power,
25 J0256]
Subsequently, the control unit 150 of the information processing device LOO
determines whether the correlator output of a certain correlator among the plurality
oJ" correlators is greater Ehan the corresponding detection threshold (step S763),
[0757]
,10 When the correlator outpul of the certain correlator among the plurality of
cot relators is greater than the corresponding detection threshold (step S763), the
SP35B5HVVO0I
o2/l42
conlro] unit 150 nl the information processing device 300 sets ihe pael('()L otherji l A n „ Expression 12
(where n - 0 lo N)
iO f0272]
[Operation example of Iran smiss ion and reception process!
FIG 2fi is a flowchart showing a packet detection determination process (the
processing order of stop S730 shown iu FIG 17) in the transmission and reception
process by the information processing device 100 according to the sixth embodiment
15 of the present technology,
10273]
First, the control unit 150 of the information processing device 100
performs measurement of the RSSI on a signal input via the antenna 141 and retains
the RSSI obtained through the measurement (step S77l)r
20 [0274]
Subsequently, the control unit 150 of the information processing device 100
compares the measured RSST io the retained application levels (F_far and Lnear) o!
the physical headers and decides the index of the physical header to be applied to
detection (step S772). For example, as in the selection method of selecting the
25 transmission physical header of the self-device, it is possible to decide the index of
the physical header to be applied to the detection.
10275]
For example, when the measured RSS1 is compared to the value of T.uear
and the measured RSSI is greater than L_ near, the control unit 150 oHhe information
30 processing device 100 decides I (for the short distance) as the index of the physical
header to be used for (he correlation detection of the 'jelf-device, Conversely, when
SP:";r>ft!S]iwO{n
6(>/l42
the measured RSSJ is equal to oi" less than l.jiear. lint; control unit 150 of tlic
information processing device 100 decides 1) (for the long distance) as the index of
(ho physical header to be used lor the correlation deteclionof Ihe self-device.
[0276]
5 In Ihc decision procedure, it is assumed that there is no difference in
transmission power between the slave and master stations However, when
mlbrmaliou regarding a difference In the transmission power is retained in advance
despite ihc difference in ihc transmission power belween the slave and master
stations, Ihe determination can be performed after appropriate correction is applied
JO based on the retained information regarding the diOerence in the transmission power.
J0277]
Subsequently, the control unit 150 of the informal ion processing device 100
switches internal calculation of the correlator and performs the correlation
calculation lo correspond to the preamble sequence of the physical header with the
!Fi decided index (step S771). Here, the switching of the internal calculation is Jhe
same process as (lie process corresponding to "positive and negative inversion on a
part of ton tent" which is the above-described method of generating the PLCP
Preamble portion,
[027S]
20 | Bxamplc of configuration of correlator]
FIG, 27 is a diagram showing an example of Ihe configuration of a
correlator included in the information processing device 100 according to the sixth
embodiment of the present technology. Here, a of FIG. 27 is a modification
example of a of FIG 11 and b of FIG 27 is a modification of b of TIG 11, FIG 27
25 shows an example of the configuration of the correlator in which calculation of sign
inversion is applied based on a switch signal determined with the RSSI, By
realizing ihe configuration in Ihis way, it is possible lo easily configure the correlator
of another preamble,
[0279]
30 1'or example, when an input PLCP Preamble is correctly consistent with
calculation of the correlator, it is possible to obtain a large correlator output,
57/142
However, when the calculation is different, liic correlator output decreases.

CLAIMS
Claim 3
An information processing. device comprising:
a conlroi unit configured to perform control such [hat reception nl' a packet
is stopped during the reception according to a JITSI condition find an operation is
performed assuming that FJ carrier sense is an idle state fur a time from sl-ail of the
reception of (he- packel to stop of Ihe reception of the packet according to a second
condition.
Claim 2
The information processing device according to claim !,
wherein, when the second condition is satisfied after the stop of the
reception of the packet, the control unit performs control such that a latency time
corresponding hi an niter Iramc space (IKS) does no) occur,
Claim 3
The informalion processing device according to claim. 1,
wherein, when die second condition is satisfied after the stop of the
reception of the packed the control unit performs control such thai a time length from
a transition time of the carrier sense to BUSY at the lime of Llic rccepiitm of the
packet to a reception stop time is converted into a slot time and is subtracted from a
back o IT counter.
Claim 4
The iti formation processing device according to claim 3,
wherein, when a result after the subtraction is a negative value, me control
unit treats Ihe result as 0.
Claim 5
The information processing device according to claim 3,
wherein, when a result after the subtraction is a negative value, the control
Sj-'^r.mvooi
1iB'l42
unit sets a value obtained by illuming *be resull to a positive value corresponding to
the negative value so lhat ttic value does not exceed the back of! counter before Lhe
subtraction.
5 Claim 6
The information processing device according to claim 1:
wherein the first condition includes a condilion that a CRC calculation result
obtained when a physical header of the packet during the reception is a target not be
identical to CRC information described in the physical header.
10
Claim 7
Ihe information processing device according lo claim 6,
wherein, when in formation regarding an identifier for identifying a network
is present in the physical header of the packet, the first condition further includes a
I ft condition that the information regarding Ihe identifier be different from a network
identifier of a network 1o which the information processing device belongs,
Claim 8
The information processing device according to claim 6,
20 wherein the first condition furlher includes a condition that a preamble
correlator output level of the packet during the reception in antenna inpuJ conversion
be less lhan a threshold derived from information described in ihe physical header of
the packet.
2b Claim 9
The information processing device according to claim 8,
wherein, when information regarding an identifier for identifying a network
is present in the physical header of the packet and the information regarding the
identifier is identical to a network identifier of a network to which ihe information
[50 processing device belongs, the control unit continues ihe reception without stopping
the reception,
139/142
Claim 10
Tin: information processing device according to claim S,
wherein the control unit performs the derivation based on matching between
5 an index described in the physical header of [lie packet and a table of thresholds
shared in advance.
Claim 11
The information processing device according to claim 8,
!0 wherein the control unit performs the derivation through conversion based
on a value described in the physical header of the packet and information regarding a
unit and quantization shared in advance,
Claim 12
ITi The information processing device accordingly claim 1,
wherein the second condition includes the lir^t condition.
Claim 13
The information processing device according to claim t s
20 wherein the control unit determines necessity and non-necessity of the
operation using a condition (hat reception power of the paekel during die reception
be less lhati a prc-deeided energy detection threshold, as the second condition.
Claim 14
25 The information processing device according to claim 1,
wherein the control unit determines necessity and non-necessity of the
operation using a condition lhat transmission suppression by virtual carrier sense not
be applied at the lime of stopping of the reception ol" the packet, as the second
condition.
30
Claim 15
The inlbrmaEuni processing dcvice according In claim l,
wherein the eoulrol unit determines necessity and non-necessity of Lbe
operation using a condition that a CRC calculation result obtained when a physical
J reader of the packet is a target not he identical lo CRC' information described in the
5 physical header and a preamble correlator output level of the packet in antenna input
conversion be less than a minimum packet detection threshold among applicable
packet deletion thresholds, as the second condition,
Claim 16
10 The information processing device according Eo claim 1,
wherein, when the second condition is not satisfied after stop of Jbe
rcceplion ofthc packel: the control uml performs control such that transmission from
the information processing device during a conlinutly period of the packet transfer is
prohibited,
Claim 17
The information processing device according to claim \ 6,
whevein: when the second condition is not satisfied ailer the stop of (be
reception ofthc packel and the transmission from the information processing device
20 during the continuity period of the packet transfer is prohibited, the control unit
performs control such that a reply to a frame which is destined for the mlbrmation
processing device and requests the reply is transmitted when the frame is received.
Claim IK
2fi An information processing method comprising:
a first procedure of stepping receplion of a packet during the reception
according to a first condition; and
a second procedure of performing an operation assuming Ibal a carrier sense
is an idle state for a time from start of the reception of the packet to stop of the
30 reception of the packet according to a second condition.
Cbiiin 19
A pFOgntin causing a compiler to cxecule:
a [irnt procedure of slopping recqiti.ni of ;i packet during the reception
according to a iirsl titJtldition5 iviid
a second procedure of peribvining. an operation HSK timing thrit a carrier ^uac
is an idle slate for a time from stmt of the rcceplioTi of the packet to stop of the
leceptiiii! of the packet according to n second condition.