EXHIBIT A

Case 6:20-cv-00491-ADA Document 37 Filed 11/06/20 Page 1 of 18
(12) United States Patent 

Knecktet al. 

US008.730905B2 

(10) Patent No.: US 8,730,905 B2 

(45) Date of Patent: May 20, 2014 

(54) 

(75) 

(73) 

(*) 

(21) 

(22) 

(65) 

(51) 

(52) 

(58) 

TRANSMISSION RESOURCE RESERVATION 

SCHEME 

Inventors: Jarkko Kneckt, Espoo (FI); Mika 

Kasslin, Espoo (FI); Janne Marin, 

Espoo (FI) 

Assignee: Nokia Corporation, Espoo (FI) 

Notice: Subject to any disclaimer, the term of this 

patent is extended or adjusted under 35 

U.S.C. 154(b) by 593 days. 

Appl. No.: 12/939,314 

Filed: Nov. 4, 2010 

Prior Publication Data 

US 2012/O113952 A1 May 10, 2012 

Int. C. 

H0474/00 (2009.01) 

U.S. C. 

USPC ........... 370/330; 370/336; 370/338: 370/341; 

37O/348 

Field of Classification Search 

USPC ................. 370/328,329, 330, 348, 465, 468: 

455/68, 73, 434, 464 

See application file for complete search history. 

(56) References Cited 

U.S. PATENT DOCUMENTS 

7.050.452 B2 * 5/2006 Sugar et al. ................... 370/465 

7,116,682 B1 * 10/2006 Waclawsky et al. ... 370/468 

2005/0208956 A1* 9/2005 Takagi et al. ... ... 455,464 

2007.0054667 A1* 3, 2007 Lee et al. .... ... 455,434 

2008/0227403 A1* 9, 2008 Taki ................................ 455.68 

2011/0053521 A1 3/2011 Cordeiro ......................... 455/73 

OTHER PUBLICATIONS 

IEEE 802.11-09/0992r 15, “IEEE P802.11 Wireless LANs, Specifi 

cation Framework for TGae', Robert Stacey, Intel, Sep. 2010, (27 

pages). 

* cited by examiner 

Primary Examiner — Brian DNguyen 

Assistant Examiner — Toan Nguyen (74) Attorney, Agent, or Firm — Harrington & Smith 

(57) ABSTRACT 

A method, apparatus, and computer program for acquiring 

transmission resources during a transmission period is pro vided. A first communication apparatus is arranged to utilize 

at least one other communication apparatus to reserve at least one additional transmission band for the first communication 

apparatus during the transmission period of the first commu 

nication apparatus. Upon reception of a message indicating 

availability of additional transmission band(s) from the at 

least one other communication apparatus, the first communi 

cation apparatus is configured to increase its transmission 

band during the transmission period. 

26 Claims, 4 Drawing Sheets 

 20 

Case 6:20-cv-00491-ADA Document 37 Filed 11/06/20 Page 2 of 18
U.S. Patent May 20, 2014 Sheet 1 of 4 US 8,730,905 B2 

570 533) 5.490 5710. Si3S S835 

MHz MHz MHz MHz MHz MHz 

IEEE channel 4 as S. S. as S. 533 S : 5 & 88 55 & 8ts 2 

20MHz VVVV VVVVV VVVV 

40MH, V, V V YYYY-A V 

80MHz CW 

160MHz 

COMMUNICATION APPARATUS 1 COMMUNICATION APPARATUS 2 

SI: ACQUIRE TRANSMISSION OPPORTUNITY 

S2: DECIDETOUTILIZE HIGHERBANDWIDTH 

S3: COMMUNICATE RESERVATION REQUEST 

S4: MONITORFORAVAILABLE FREQUENCYBAND 

TRANSMISSION S5: DETEC AVAILABLE FREQUENCYBAND 

OPPORTUNITY S6: COMMUNICATE RESERVATION RESPONSE 

S7. INCREASE BANDWIDTH & 

TRANSMTDATAONHGHERBAND 

Fig 2 

 

Case 6:20-cv-00491-ADA Document 37 Filed 11/06/20 Page 3 of 18
U.S. Patent May 20, 2014 Sheet 2 of 4 US 8,730,905 B2 

QUATERNARY CH 

TERTARY CH 

SECONDARY CH -BUSY-RESOK 

PRIMARY CH 

O-TXOPACO-O TXOPAC TXOP 

Fig 3 

QUATERNARY CH 

TERTARY CH 

SECONDARY CH 

PRIMARY CH 

O-TXOPACQ-o TXOP 

Fig. 4 

QUATERNARY CH 

TERTARY CH 

SECONDARY CH 

PRIMARY CH 

O-TXOPACQ-0 

PRIMARY CH OF BSS2 

QUATERNARY CH 

TERTARY CH 

SECONDARY CH 

PRIMARY CH 

O-TXOPACQ-o 

 

Case 6:20-cv-00491-ADA Document 37 Filed 11/06/20 Page 4 of 18
U.S. Patent May 20, 2014 Sheet 3 of 4 US 8,730,905 B2 

QUATERNARY CH 

TERTARY CH 

SECONDARY CH 

PRIMARY CH 

O-TXOPACO-0 

QUATERNARY CH 

TERTARY CH 

SECONDARY CH 

PRIMARY CH 

a-TXOPACQ-e 

QUATERNARY CH 

TERTARY CH 

SECONDARY CH 

PRIMARY CH 

O-TXOPACQ-o 

Fig 9 

REPORT | DURATION TO NSI CHANNEL CHANNEL Ac()|EPORTME) , "E"|OPIONs). ID2(2) 

Fig 10 

 

Case 6:20-cv-00491-ADA Document 37 Filed 11/06/20 Page 5 of 18
U.S. Patent May 20, 2014 Sheet 4 of 4 US 8,730,905 B2 

O 

COMMUNICATION CONTROLLERCIRCUITRY 

12 13 

4. 16 

30 

MEMORY 

SOFTWARE 

DATAPART 

RADIO INTERFACE COMPONENTS 

Fig 11 

 

 

 

 

 

 

Case 6:20-cv-00491-ADA Document 37 Filed 11/06/20 Page 6 of 18
US 8,730,905 B2 

1. 

TRANSMISSION RESOURCE RESERVATION 

SCHEME 

FIELD 

The invention relates to the field of wireless telecommuni 

cations and, particularly, to reserving transmission resources 

in a wireless telecommunication system. 

BACKGROUND 

Wireless Local Area Network (WLAN) has undergone vast 

development in order to increase throughput. Task groups 

such as 802.11b. 802.11a, 802.11g and 802.11n have demon 

strated continuous improvement of the WLAN radio through 

put. 802.11 ac is another task group that is developing the 

WLAN radios that operate at a frequency spectrum below 6 

GHz and especially at 5 GHz. There exist other task groups 

within the IEEE 802.11 standardization. 

Channelization rules for 802.11ac radios are currently 

under development. The rules define the frequency channels 

available for 802.11ac transmitters. The rules are based on a 

scheme of a primary channel and secondary channels. The 

scheme follows a principle where each network or basic ser 

Vice set (BSS) has a primary channel and Zero or more sec 

ondary channels. The primary channel is used for channel 

contention, and transmission opportunity (TXOP) is gained 

based on carrier sensing on the primary channel. 

BRIEF DESCRIPTION 

According to an aspect of the present invention, there is 

provided a method comprising: acquiring, in a first wireless 

communication apparatus, a transmission period to transmit 

data on a first frequency band within a determined transmis 

sion time interval; determining to utilize a bandwidth higher 

than that of the first frequency band during the transmission 

period; causing transmission of a reservation request message 

to at least second wireless communication apparatus, wherein 

the reservation request message instructs the second wireless 

communication apparatus to reserve at least one additional 

frequency band for the first wireless communication appara 

tus during the transmission period; receiving a reservation 

response message from the at least second wireless commu 

nication apparatus, wherein the reservation response message 

indicates that said at least one additional frequency band is 

available for the first wireless communication apparatus to 

use in transmission during the transmission period; and, in 

response to the reception of the reservation response mes 

sage, increasing transmission band to comprise said first fre 

quency band and said at least one additional frequency band 

during the transmission period. 

In an embodiment, the method further comprises causing 

the transmission of the reservation request message at the 

beginning of the transmission period. 

In an embodiment, the method further comprises: causing 

transmission of data only on the first frequency band until the 

reservation response message is received during the transmis 

sion period; and causing transmission of data on the first 

frequency band and on the at least one additional frequency 

band after the reservation response message is received dur 

ing the transmission period. 

In an embodiment, the method further comprises receiving 

the reservation response message during a time interval 

between data transmission intervals during the transmission 

period. 

10 

15 

25 

30 

35 

40 

45 

50 

55 

60 

65 

2 

In an embodiment, the reservation request message com 

prises an identifier of the second wireless communication 

apparatus, and at least one frequency channel indicator indi 

cating the at least one additional frequency band that is to be 

reserved by the second wireless communication apparatus. According to an aspect, there is provided a method, com 

prising: receiving, from a first wireless communication appa 

ratus in a second communication apparatus, a reservation 

request message instructing the second wireless communica 

tion apparatus to reserve at least one frequency band for the 

first wireless communication apparatus during a transmission 

period of the first wireless communication apparatus; moni 

toring for availability of the at least one frequency band 

during the transmission period of the first wireless commu 

nication apparatus; in response to detection of availability of 

the at least one frequency band during the transmission period 

of the first wireless communication apparatus, causing trans 

mission of a reservation response message to the first wireless 

communication apparatus, wherein the reservation response 

message indicates that said at least one additional frequency 

band is available for the first wireless communication appa 

ratus to use in transmission during the transmission period of 

the first wireless communication apparatus. 

In an embodiment, the method further comprises causing, 

in the second wireless communication apparatus, transmis 

sion of a reservation message reserving the at least one fre 

quency band by triggering a network allocation vector setting 

to the reserved at least one frequency band. In an embodi 

ment, the reservation message is a clear-to-send message. In 

an embodiment, the second wireless communication appara 

tus is requested to reserve a plurality of frequency bands, and 

the method further comprises causing the transmission of the 

reservation message on each frequency band separately. 

In an embodiment, the method further comprises: receiv 

ing, in the reservation request message, transmission param 

eters related to transmission of the reservation response mes 

sage; and transmitting the reservation response message 

according to the received transmission parameters. In an 

embodiment, the transmission parameters relate to at least 

one of timing and transmission frequency of the reservation 

response message. 

According to an aspect, there is provided an apparatus, 

comprising means for carrying out any one of the above 

described methods. 

According to an aspect, there is provided a computer pro 

gram product embodied on a distribution medium readable by 

a computer and comprising program instructions which, 

when loaded into an apparatus, execute any one of the above 

described methods. According to an aspect, there is provided 

a computer program distribution medium or any other manu 

factured article configured to store the above-described com 

puter program product. 

According to an aspect, there is provided an apparatus 

comprising: at least one processor; and at least one memory 

including a computer program code, wherein the at least one 

memory and the computer program code are configured, with 

the at least one processor, to cause the apparatus to: acquire a 

transmission period to transmit data on a first frequency band 

within a determined transmission time interval; determine to 

utilize abandwidth higher than that of the first frequency band 

during the transmission period; cause transmission of a res 

ervation request message from a first wireless communica 

tion apparatus to at least a second wireless communication 

apparatus, wherein the reservation request message instructs 

the second wireless communication apparatus to reserve at 

least one additional frequency band for the first wireless 

communication apparatus during the transmission period; 

Case 6:20-cv-00491-ADA Document 37 Filed 11/06/20 Page 7 of 18
US 8,730,905 B2 

3 

receive a reservation response message from the at least sec 

ond wireless communication apparatus, wherein the reserva 

tion response message indicates that said at least one addi 

tional frequency band is available for the first wireless 

communication apparatus to use in transmission during the 

transmission period; and in response to the reception of the 

reservation response message, cause the first wireless com 

munication apparatus to increase the transmission band to 

comprise said first frequency band and said at least one addi 

tional frequency band during the transmission period. 

In an embodiment, the at least one memory and the com 

puter program code are configured, with the at least one 

processor, to cause the apparatus to cause the transmission of 

the reservation request message at the beginning of the trans 

mission period. 

In an embodiment, the at least one memory and the com 

puter program code are configured, with the at least one 

processor, to cause the apparatus to: cause transmission of 

data only on the first frequency band until the reservation 

response message is received during the transmission period; 

and cause transmission of data on the first frequency band and 

on the at least one additional frequency band after the reser 

Vation response message is received during the transmission 

period. 

In an embodiment, the at least one memory and the com 

puter program code are configured, with the at least one 

processor, to cause the apparatus to receive the reservation 

response message during a time interval between data trans 

mission intervals during the transmission period. 

In an embodiment, the reservation request message com 

prises an identifier of the second wireless communication 

apparatus, and at least one frequency channel indicator indi 

cating the at least one additional frequency band that is to be 

reserved by the second wireless communication apparatus. According to an aspect, there is provided an apparatus, 

comprising: at least one processor; and at least one memory including a computer program code, wherein the at least one 

memory and the computer program code are configured, with 

the at least one processor, to cause the apparatus to: cause 

reception of a reservation request message from a first wire 

less communication apparatus the reservation request mes 

sage instructing the apparatus to reserve at least one fre 

quency band for the first wireless communication apparatus during a transmission period of the first wireless communi 

cation apparatus; monitor for availability of the at least one 

frequency band during the transmission period of the first 

wireless communication apparatus; in response to detection 

of availability of the at least one frequency band during the 

transmission period of the first wireless communication appa 

ratus, cause transmission of a reservation response message 

to the first wireless communication apparatus, wherein the 

reservation response message indicates that said at least one 

additional frequency band is available for the first wireless 

communication apparatus to use in transmission during the 

transmission period of the first wireless communication appa 

ratuS. 

In an embodiment, the at least one memory and the com 

puter program code are configured, with the at least one 

processor, to cause the apparatus to cause transmission of a 

reservation message reserving the at least one frequency band 

by triggering a network allocation vector setting to the 

reserved at least one frequency band. In an embodiment, the 

reservation message is a clear-to-send message. 

In an embodiment, the apparatus is requested to reserve a 

plurality of frequency bands, wherein the at least one memory 

and the computer program code are configured, with the at 

10 

15 

25 

30 

35 

40 

45 

50 

55 

60 

65 

4 

least one processor, to cause the apparatus to cause the trans 

mission of the reservation message on each frequency band 

separately. 

In an embodiment, the at least one memory and the com 

puter program code are configured, with the at least one 

processor, to cause the apparatus to: receive, in the reserva 

tion request message, transmission parameters related to 

transmission of the reservation response message; and cause 

transmission of the reservation response message according 

to the received transmission parameters. The transmission 

parameters may relate to at least one of timing and transmis 

sion frequency of the reservation response message. 

In an embodiment, the apparatus further comprises radio 

interface components enabling the apparatus to access a radio 

medium. 

LIST OF DRAWINGS 

Embodiments of the present invention are described below, 

by way of example only, with reference to the accompanying drawings, in which 

FIG. 1A illustrates communication network to which some 

embodiments of the invention may be applied: 

FIG.1B illustrates a channel allocation principle according 

to an embodiment; 

FIG. 2 illustrates a flow diagram of a process according to 

an embodiment of the invention; 

FIGS. 3 to 9 illustrate embodiments for acquiring addi 

tional transmission band for a communication apparatus dur 

ing a transmission opportunity of the communication appa 

ratus; 

FIG. 10 illustrates fields of a reservation request message according to an embodiment of the invention; and 

FIG. 11 illustrates a block diagram of an apparatus accord 

ing to an embodiment of the invention. 

DESCRIPTION OF EMBODIMENTS 

The following embodiments are exemplary. Although the 

specification may refer to “an”, “one', or “some' embodi 

ment(s) in several locations, this does not necessarily mean 

that each Such reference is to the same embodiment(s), or that 

the feature only applies to a single embodiment. Single fea 

tures of different embodiments may also be combined to 

provide other embodiments. Furthermore, words "compris ing” and “including should be understood as not limiting the 

described embodiments to consist of only those features that 

have been mentioned and Such embodiments may contain 

also features/structures that have not been specifically men 

tioned. 

A general architecture of a wireless telecommunication 

system to which embodiments of the invention may be 

applied is illustrated in FIG. 1A. FIG. 1A illustrates two 

groups of wireless communication devices forming two basic 

service sets, i.e. groups of wireless communication devices 

comprising an access point (AP) 100, 112 and terminal sta 

tions (STA) 102, 104, 110, 114 communicating with the 

access points 100, 112 of their respective groups. A basic 

service set (BSS) is a basic building block of an IEEE 802.11 

wireless local area network (WLAN). The most common 

BSS type is an infrastructure BSS that includes a single AP 

together with all associated STAs. The AP may be a fixed AP 

as AP 112, or it may be a mobile AP as AP 100. The APs 100, 

112 may also provide access to other networks, e.g. the Inter 

net 120. In another embodiment, at least one of the BSSs is an 

independent BSS (IBSS) or a mesh BSS (MBSS) without a 

dedicated AP and in Such embodiments the communication 

Case 6:20-cv-00491-ADA Document 37 Filed 11/06/20 Page 8 of 18
US 8,730,905 B2 

5 

device 100 may be a non-access-point terminal station. While 

embodiments of the invention are described in the context of 

the above-described topologies of IEEE 802.11 and, particu 

larly, IEEE 802.11ac, it should be appreciated that other 

embodiments of the invention are applicable to networks 

based on other specifications, e.g. other versions of the IEEE 

802.11, WiMAX (Worldwide Interoperability for Microwave 

Access), UMTS LTE (Long-term Evolution for Universal 

Mobile Telecommunication System), and other networks 

having cognitive radio features, e.g. transmission medium 

sensing features and adaptiveness to coexist with radio access 

networks based on different specifications and/or standards. 

The 802.11n specifies a data transmission mode that 

includes 20 MHz wide primary and secondary channels. The 

primary channel is used in all data transmissions, and with 

clients supporting only the 20 MHZ mode. A further definition 

in 802.11n is that the primary and secondary channels are 

adjacent. The 802.11n specification also defines a mode in 

which a STA can have only one secondary channel which 

results in a maximum bandwidth of 40 MHz. IEEE 802.11ac 

task group extends Such an operation model to provide for 

wider bandwidths by increasing the number of secondary 

channels from 1 up to 7, thus resulting in bandwidths of 20 

MHz, 40 MHz, 80 MHz, and 160 MHz. FIG.1B illustrates an 

exemplary channel structure for 20 MHz, 40 MHz, 80 MHz, 

and 160 MHZ channels. In this example, a 40 MHZ transmis 

sion band is formed by two contiguous 20 MHz bands (de 

noted by numerals 1 and 2 in FIG. 1B), and an 80 MHz 

transmission band is formed by two contiguous 40 MHz 

bands (numerals 1, 2, 3). However, a 160 MHz band may be 

formed by two contiguous (numerals 1 to 4) or non-contigu 

ous 80 MHz bands (numerals 1 to 3 for a first 80 MHz band 

and any one of bands denoted by numerals 5 and 6 for a 

second 80 MHz band). 

As mentioned above, the transmission band of a BSS con 

tains the primary channel and Zero or more secondary chan 

nels. The primary channel is used for channel contention, and 

a transmission opportunity (TXOP) is gained based on carrier 

sensing in the primary channel. Every STA has a time dura 

tion (defined by a backoff factor), and if the STA detects that 

the primary channel has been free for the time duration, it 

gains the TXOP and starts transmission. If another STAgains 

the TXOP before that, the channel sensing is suspended, and 

the STA proceeds with the channel sensing after the TXOP of 

the other STA has ended. The time duration (the backoff 

factor) may not be reset at this stage, and the time duration 

that already lapsed before the Suspension is also counted, 

which means that the STA now has a higher probability of 

gaining the TXOP. A secondary channel may be used in the 

transmission if it has been free for a determined time period 

(may be the same or different time period than that used for 

gaining the TXOP) just before TXOP start time in order for 

the contending STA to take the secondary channel in use. Let 

us consider a scenario where a STA gains a TXOP for the 

primary channel, but the secondary channel is assessed to be 

occupied by another STA of another BSS, for example. When 

the TXOP begins, the STA carries out the transmission on the 

primary channel for the duration of the TXOP even if the 

secondary channel is free immediately after the beginning of 

the TXOP. 

An embodiment of the present invention utilizes other 

STAS to reserve additional bandwidth for the STA that has the 

TXOP (TXOP holder) during the TXOP. The TXOP may be 

defined as a continuous period of time reserved for the TXOP 

holder to transmit data on the primary channel and Zero or 

more secondary channels. FIG. 2 illustrates an embodiment 

of a procedure for using another STA to reserve additional 

10 

15 

25 

30 

35 

40 

45 

50 

55 

60 

65 

6 

bandwidth for the TXOP holder. Note that the procedure includes steps carried out in the TXOP holder (a first com 

munication apparatus 1 in the Figure), steps carried out in the 

reserving STA (a second communication apparatus 2 in the 

Figure), and communication between the TXOP holder and 

the reserving STA. Note that the reserving STA may be a 

terminal device or an access point of the BSS. Referring to 

FIG. 2, the first communication apparatus acquires in S1 a 

transmission period to transmit data on a first frequency band 

within a determined transmission time interval. An embodi 

ment of the transmission period is the above-mentioned 

TXOP and the transmission time interval is referred to as a 

TXOP interval. Thus, the first communication apparatus 

becomes the TXOP holder for the TXOP interval. In S2, the 

TXOP holder determines to utilize a bandwidth higher than 

that of the first frequency band during the transmission oppor 

tunity. In other embodiments, the decision on the bandwidth 

to be used is made before the channel reservation, and in such 

embodiments, S2 is executed before S1. It can be understood 

that a communication apparatus first determines abandwidth 

that it needs and, then, attempts to reserve the TXOP for the 

determined bandwidth. In response to the decision in S2 (and 

the bandwidth it was able to reserve in S1), the TXOP holder 

causes transmission of a reservation request message to at 

least the second communication apparatus in S3. The reser 

Vation request message instructs the second communication 

apparatus to reserve at least one additional frequency band for 

the first communication device during the transmission 

opportunity. The second communication apparatus receives 

the reservation request message from the TXOP holder in S3. 

In response to the reception of the reservation request mes 

sage, the second communication apparatus becomes the 

reserving STA, and it starts monitoring for availability of the 

at least one frequency band during the transmission opportu 

nity of the first wireless communication apparatus. The moni 

toring may comprise carrying out channel sounding on the 

least one frequency band the reserving STA was instructed to 

reserve. In S5, the reserving STA detects an available fre 

quency band among the at least one frequency band it was 

instructed to reserve. The reserving STA may also reserve the 

frequency band by transmitting a signal that prevents other 

STAs to transmit on the detected frequency band. In response 

to detection of availability of the at least one frequency band 

during the transmission opportunity of the first communica 

tion apparatus in S5, the reserving STA causes transmission 

of a reservation response message to the TXOP holder. The 

reservation response message indicates that the detected fre 

quency band is available for the first wireless communication 

apparatus to use in transmission during the transmission 

opportunity of the TXOP holder. The TXOP holder receives 

the reservation response message in S6. In response to the 

reception of the reservation response message, the reserving 

STA increases in S7 the bandwidth of the transmission during the TXOP to comprise said first frequency band and the at 

least one frequency band indicated in the reservation response 

message. The TXOP holder thus uses an increased transmis 

sion band for the remaining transmission opportunity in S7. 

thereby transmitting data on a frequency band having the 

increased bandwidth. Accordingly, steps S1 to S7 may be 

carried out during the same TXOP. 

Advantages of the above-described embodiment include 

improved spectral efficiency, as the transmission resources of 

the TXOP holder may be flexibly increased during the TXOP, 

thereby improving the performance of the TXOP holder and 

the BSS. 

When the channel utilization of the wireless telecommu 

nication system, in which some embodiments of the invention 

Case 6:20-cv-00491-ADA Document 37 Filed 11/06/20 Page 9 of 18
US 8,730,905 B2 

7 

are utilized, is restricted, an embodiment of the invention is to 

control the channel reservation according to frequency band 

allocation rules of the wireless telecommunication system. 

Let us consider the example of FIG. 1B, wherein the channel 

utilization principle is such that a higher bandwidth is a com 

bined bandwidth of contiguous bands up to 80 MHz band. For 

the 160 MHZ transmissions, the two 80 MHz bands may be 

contiguous or non-contiguous. As a consequence, the TXOP 

holder may increase its transmission bandwidth in the order 

indicated in FIG. 1B by numerals 1 to 6. Let us assume that a 

transmission band indicated by numeral 1 is the primary 

channel, and the TXOP holder gains the TXOP initially for 

the primary channel. As a consequence, the TXOP holder 

may transmit the reservation request message instructing 

another STA to reserve at least the frequency band indicated 

by numeral 2 (a secondary channel) to gain a second 20 MHZ 

channel. Optionally, the reservation request may instruct the 

other STA to reserve additional frequency bands, e.g. at least 

one of those indicated by numerals 3 (tertiary channel), 4 

(quaternary channel), 5, and 6. In another embodiment, the 

TXOP holder transmits the reservation message to plurality 

of other STAs so that the reservation becomes distributed 

amongst a plurality of reserving STAs. Upon reception of the 

reservation response message(s) from the reserving STAS, the 

TXOP holder increases the transmission bandwidth such that 

the tertiary channel is not taken into use before the secondary 

channel, and the quaternary channel is not taken into use 

before the tertiary and the secondary channel. In other words, 

if the TXOP holder receives a reservation response message 

for the secondary channel, it may increase the transmission 

band to comprise the primary and the secondary channel at 

any time after the reception and processing the reservation 

response message for the secondary channel. Thereafter, the 

reception of the reservation response message for the tertiary 

channel triggers the increase of the transmission bandwidth to 

comprise the primary, secondary, and tertiary channel. How 

ever, if the reservation response message for the tertiary chan 

nel is received before the reservation response message for 

the secondary channel, the TXOP holder may be configured 

to wait until the reservation response message for the second 

ary channel is received, thereby complying with the channel 

utilization specifications of the BSS. With respect to the 160 

MHZ transmission, the other 80 MHz band (any one of the 

bands denoted by 4, 5, and 6) may be taken into use after the 

first 80 MHz band (bands 1 to 3) has been reserved. If the 

system Supports contiguous 160 MHZ transmission, the other 

80 MHz band may be the band denoted by numeral 4. If the 

system Supports non-contiguous 160 MHZ transmission, the 

other 80 MHz band may be fixed, e.g. the band denoted by 

numeral 5. If the system supports a channel allocation where 

the other 80 MHz band may be an arbitrary band, any one of 

the bands designated by numerals 5 and 6 may be reserved. In 

other embodiments where all transmission bands may be 

non-contiguous, the utilization of the reserved channels is 

more flexible, and the reserved channels may be taken into 

use in the order that they become reserved for the TXOP 

holder. Note also that if the TXOP holder gains the TXOP for 

the maximum bandwidth, e.g. 160 MHz, the transmission of 

the reservation request message may be prevented for that 

TXOP. 

Let us now consider some embodiments of the invention to 

implement the reservation of additional transmission band for 

the TXOP holder with reference to FIGS. 3 to 9. The FIGS. 3 

to 9 illustrate time-frequency tables where time runs in the 

horizontal direction, and channels of the BSS are arranged vertically. In the described embodiments, above-described 

channel allocation rules (FIG. 1B) are assumed, but it should 

5 

10 

15 

25 

30 

35 

40 

45 

50 

55 

60 

65 

8 

be understood that the invention is applicable to any other 

channel allocation rules. In the described embodiments, the 

TXOP is obtained to at least the primary channel but, in 

general, the primary channel may be replaced by any other 

channel of a communication system that does not define 

primary channels. 

Referring to FIG. 3, a communication device of a BSS 

acquires the TXOP to the primary channel, while the other 

channels (secondary, tertiary, and quaternary channel) are 

detected to be used by another STA (of another BSS). As a 

consequence, the communication device becomes the TXOP 

holder. When the BSS supports the IEEE 802.11 networking, 

the TXOP may be acquired through Enhanced Distributed 

Channel Access (EDCA) backoff calculation, as described 

above and as is known in connection with IEEE 802.11 net 

works. The TXOP holder may define the operation during the 

TXOP and it may transmit frames, poll, and receive frames 

that are destined to it, receive acknowledgements, sense other 

operating channels for PIFS (point coordination inter frame 

space) duration through Clear-Channel Assessment (CCA) 

procedure or, if optional reverse direction grant option is 

supported, change the TXOP Holder. With respect to the 

channel sensing, if a sensed channel is detected to contain no 

transmissions for the PIFS duration, the channel is assumed to 

be free for utilization. Upon deciding to attempt to increase 

the transmission band (S2 of FIG. 2), the TXOP holder pre 

pares the reservation request message (AOI. Announcement 

of Intent message in FIGS. 3 to 9), and transmits the AOI 

message at the beginning of the TXOP to at least one other 

STA of the BSS. An example of the structure of the AOI 

message will be described below. The AOI message may be 

transmitted on at least the primary channel regardless of the 

number of channels the TXOP holder has reserved. In an 

embodiment, the AOI message is transmitted on all channels 

reserved for the TXOP to ensure CCA and PLCP (Physical 

Layer Convergence Procedure) protection for all the channels 

of the TXOP. In this case the AOI message may instruct a 

second communication apparatus of the BSS to reserve the 

specified channel, e.g. secondary channel, thus becoming a 

reserving STA. In response to the reception of the AOI mes 

sage, the reserving STA starts to Sound the secondary channel 

for any NAV-triggering (network allocation vector) or PLCP 

header containing transmissions or to detect energy from 

transmission (CCA). Meanwhile, the TXOP holder transmits 

data to a receiving STA of the BSS. The receiving STA may be 

other STA than the reserving STA. Upon detection that the 

secondary channel becomes available, the reserving STA may 

transmit a reservation message on the secondary channel. The 

reservation message may be any message that triggers the 

NAV protection for the secondary channel. One example of 

such a message is Clear-to-send message (CTS) of IEEE 

802.11. As known from the IEEE 802.11 specifications, the 

transmission of the reservation message triggering the NAV 

protection reserves the channel for a determined period of 

time after the transmission of the reservation message, and 

the duration of the NAV protection may be included in the 

reservation message. 

Upon transmitting the reservation message, the reserving 

STA may transmit the reservation response message (OK in 

the Figures) to the TXOP holder. The reservation response 

message may be communicated (transmitted and received) 

during a time interval between data transmission intervals 

during the transmission opportunity. The reservation 

response message may be a Clear-to-Send message. If the 

channel is determined not to be free within a given time 

duration, the reserving STA may omit the transmission of the 

reservation response message, or the reserving STA may 

Case 6:20-cv-00491-ADA Document 37 Filed 11/06/20 Page 10 of 18
US 8,730,905 B2 

9 

transmit a reservation response message comprising an infor 

mation element indicating unsuccessful reservation. Trans 

mission timing of the reservation response message may be 

defined by the TXOP holder in the reservation request mes 

sage, and the reservation response message may be transmit 

ted at the same time when the TXOP holder receives an 

acknowledgment to the data it has transmitted. The OK mes 

sage may be transmitted on the secondary channel (the chan 

nel the reserving STA reserved) in this embodiment. After the 

acknowledgment period and in response to the reception of 

the reservation response message, the TXOP holder may 

again carry out step S2 so as to determine whether or not it 

should try to reserve additional transmission band(s). In this 

embodiment, the TXOP holder decides to attempt to reserve 

the tertiary and the quaternary channel and, accordingly, 

transmits a new AOI message that instructs a STA of the BSS 

to become the reserving STA and to reserve the tertiary and 

the quaternary channel for the TXOP holder. In response to 

the reception of the AOI message, the reserving STA starts to 

sound the tertiary and the quaternary channels for any NAV 

triggering transmissions or other transmissions (CCA). 

Meanwhile, the TXOP holder transmits data to the receiving 

STA of the BSS. The receiving STA may be the same that 

received the initial transmission of data during the TXOP, or 

it may be a different STA. Upon detection that the tertiary 

and/or quaternary channel becomes available, the reserving 

STA may transmit the reservation message on the tertiary/ 

quaternary channel. Again, the reservation message may be 

any message that triggers the NAV protection for the channel. 

In this case, it is assumed that the reserving STA is able to 

reserve both the tertiary and the quaternary channel before the 

transmission timing of the reservation response message. As 

a consequence, the reserving STA may transmit the reserva 

tion response message on both reserved channels as shown in 

FIG. 3. This arrangement adds CCA protection to the 

reserved channels in addition to the NAV protection. The 

transmission timing may be the acknowledgment period for 

the data transmitted by the TXOP holder. In response to the 

reception of the reservation response message, the TXOP 

holder may subsequently increase the transmission band to 

comprise the primary to quaternary channels and transmit 

data with the increased transmission bandwidth. In this 

embodiment, the acknowledgment messages are transmitted 

on the primary channel, but in other embodiments, the 

acknowledgment messages are transmitted with the same 

bandwidth used for transmitting data. With respect to the last 

transmission during the TXOP in FIG. 3, the acknowledg 

ment message may thus be transmitted on a transmission 

band comprising the primary, secondary, tertiary, and quater 

nary channel. After transmitting the reservation response 

message or upon expiry of the transmission timing of the 

reservation response message, the reserving STA may be 

configured to tune its receiver to the primary channel of the 

BSS. 

In the previous paragraph, the TXOP holder decided to 

further increase the transmission band and, as a consequence, transmitted the new reservation request message. In other 

embodiments, the new reservation request message may be 

transmitted upon failed reservation of the additional trans 

mission band attempted in connection with the first reserva 

tion request message. In such embodiments, the transmission 

timing of the reservation response message may end the chan 

nel reservation procedure, and a new reservation request mes 

sage may be used to attempt the channel reservation again by 

establishing a new channel reservation procedure. In some 

other embodiments, the reserving STA may be configured to 

attempt the channel reservation until the expiry of the TXOP. 

10 

15 

25 

30 

35 

40 

45 

50 

55 

60 

65 

10 

and transmission of a new reservation request message to 

reattempt reservation of the same channel(s) may be omitted. 

In the embodiment of FIG. 4, the TXOP holder transmits 

the reservation request message (AOI) with a bandwidth cor 

responding to the bandwidth of the TXOP (the primary and 

secondary channels in this case) so as to obtain CCA protec 

tion for all the channels of the TXOP. The TXOP holder may 

also copy multiple 20 MHz. AOI frame transmissions to the 

whole bandwidth that is reserved for the TXOP. The 20 MHZ 

transmissions contain the PLCP header defined in 802.11a 

and MAC headers, and payload is receivable by devices that 

have a different primary channel and/or by devices that do not 

support 802.11ac. In another embodiment, the reservation 

request message is transmitted on those channels of the 

TXOP that are not comprised in the primary channel of the 

BSS of the TXOP holder. The primary channel is typically 

already covered by the NAV setting so the transmission of the 

reservation request message is not necessary on the primary 

channel from the point of view of channel protection. In the 

embodiments of FIGS. 3 and 4, the reserving STA is config 

ured to reserve the channels by transmitting the reservation 

messages individually on the channels being reserved (one 

reservation message at a time). In the embodiment of FIG. 5, 

the reserving STA is configured to transmit the reservation 

messages concurrently on a plurality of channels that are to be 

reserved. Accordingly, each reservation message comprises 

separate PLCP and MAC (Medium Access Control) headers. 

An advantage of providing separate messages, e.g. 20 MHZ 

bandwidth, is that even those communication apparatuses supporting only IEEE 802.11a are able to receive the reser 

Vation messages and apply the NAV setting. Another embodi 

ment configures the reserving STA to transmit a single mes 

sage having a bandwidth corresponding to the bandwidth of 

the plurality of channels being reserved (40 MHz in this 

example). The advantage of this embodiment is that the 

reserving device needs to prepare only a single reservation 

message, and the bandwidth of the message determines the 

channels that are reserved. 

FIG. 6 illustrates the operation of the reserving STA when 

non-primary channels of two BSSs overlap, and the primary 

channels of a second BSS is outside the channels of a first 

BSS. Then, the reserving STA belonging to the first BSS may 

be configured to first transmit the reservation message on the 

primary channel of the second BSS and, thereafter, on the 

channels to be reserved. The channels to be reserved (the tertiary and the quaternary channel in FIG. 6) may even be 

reserved by another (a third) BSS at the time the reservation 

message is transmitted on the primary channel of the second 

BSS. 

In previous embodiments, the reservation response mes 

sage is transmitted on the channel(s) that are reserved by the 

reserving STA. FIG. 7 illustrates an embodiment where the 

reserving STA is configured to transmit the reservation 

response message on the primary channel of the TXOP 

holder. The transmission timing of the reservation response 

message may be defined in the reservation request message to 

enable the reserving STA to transmit the reservation response 

message without simultaneous transmission at other channels 

with other transmissions. In this embodiment, the transmis 

sion timing of the reservation response message is after the 

acknowledgment period, but it should be appreciated that the 

transmission timing and the transmission channel of the res 

ervation response message may be determined to be other 

than that illustrated in FIG. 7. Moreover, the transmission 

timing and the transmission channel of the reservation 

response message may be configured adaptively by the TXOP 

holder within the specifications of the communication system 

Case 6:20-cv-00491-ADA Document 37 Filed 11/06/20 Page 11 of 18
US 8,730,905 B2 

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of the BSS. In an embodiment, the TXOP holder is configured 

to configure the transmission timing and the transmission 

channel at times as illustrated in FIGS. 3 to 6, while at other 

times, the transmission timing and the transmission channel 

of the reservation response message as illustrated in FIG. 7. In 

other words, the transmission timing and the transmission 

channel may be selected flexibly from a plurality of transmis 

sion timings and transmission channels. An advantage in 

transmitting the reservation response message and other mes 

sages received by the TXOP holder concurrently on parallel 

channels is efficient utilization of resources, while transmis 

sion of the reservation response message as illustrated in FIG. 

7 results in simplified operation of the TXOP holder, as it 

needs to tune only to the primary channel (or the channel in 

which the acknowledgments are communicated). 

As mentioned above, the transmission timing of the reser 

Vation response message may be fixed so as to align the 

transmission of the reservation response message with other 

transmissions during the TXOP. As a consequence, there may 

exist a situation where a channel to be reserved becomes free 

for reservation just before the transmission timing of the 

reservation response message. FIG. 8 illustrates the operation 

of the reserving STA in Such a case. In this case, the reserving 

STA is configured to reserve both tertiary and quaternary 

channel. Letus assume that the quaternary channel is detected 

to be free first and that the reserving STA is configured to 

reserve it with the reservation message, as described above. 

However, the tertiary channel is detected to be free just before 

the transmission timing of the reservation response message 

so that it is not possible to transmit the reservation message 

before the transmission timing of the reservation response 

message. As a consequence, the reserving STA is configured 

to transmit a radio signal on the tertiary channel during the 

transmission timing of the reservation response message. If 

the reservation response message is configured to be trans 

mitted on the reserved channels, the radio signal may be the 

reservation response message. In Such an embodiment, the 

reservation response message functions as the reservation 

message as well, e.g. it may configure the NAV setting on the 

reserved channel. If the reservation response message is con 

figured to be transmitted on the primary channel (or on any 

other channel than the tertiary channel), the reserving STA is 

configured to transmit the reservation message (triggering the 

NAV) or any other signal (arbitrary data, test packet, random 

data sequence, etc.) on the tertiary channel triggering the 

NAV or at least CCA on the tertiary channel, thereby reserv 

ing the tertiary channel. This functionality of the reserving 

STA may be instructed by the TXOP holder in the reservation 

request message, or it may be a default functionality of the 

reserving STA such that it is not needed to be instructed 

separately by the TXOP holder. 

FIG. 9 illustrates an embodiment where the reserving STA 

is configured to utilize the channel it has reserved to transmit 

data to another STA. The transmission time period may be 

bound to a time period between the communication of the 

reservation request message and the communication of the 

reservation response message. In this embodiment, the 

reserving STA is configured to carry out Such transmissions 

only on the channel(s) it is configured to reserve for the TXOP 

holder, which may consist of channels other than the primary channel. Similarly, the STAs may be configured to receive 

Such transmissions on channels that do not include the pri 

mary channel. Referring to FIG. 9, upon reception of the 

reservation request message, the reserving STA detects that 

the quaternary channel is free. In response to the detection, 

the reserving STA determines that it has a possibility to trans 

mit data on the quaternary channel and, accordingly, it pre 

10 

15 

25 

30 

35 

40 

45 

50 

55 

60 

65 

12 

pares a data packet to be transmitted on the quaternary chan 

nel to a receiving STA. The transmission of the data packet 

may be preceded by transmission of a control message from 

the reserving STA to the receiving STA to tune to the quater 

nary channel for data reception. Then, the reserving STA 

transmits the data packet to the receiving STA and receives an 

acknowledgment (ACK) on the quaternary channel. Thereaf 

ter, the reserving STA transmits the reservation response mes 

sage at the transmission timing and on the transmission chan 

nel configured in the reservation request message. 

With respect to the reservation carried out by the reserving 

STA, the reserving STA may be configured to reserve a chan 

nel that is detected to be the primary channel of another BSS 

through the EDCA procedure (e.g. backoff calculation) in 

order to gain the TXOP for the channel. An access category (AC) of the transmission opportunity may be provided to the 

reserving STA in the reservation request message. The access 

category defines explicitly or implicitly the backoff factor. 

The access category may define a priority, and the backoff 

factor may be shorter for a high-priority AC and longer for a 

low-priority AC. The reserving STA may then transmit the 

reservation message by calculating the backoff factor accord 

ing to the received AC. If the AC is not provided the reserving 

STA may be configured to use a determined default AC and a 

corresponding backoff factor, e.g. an AC for voice (AC-VO). 

The reserving STA may be provided with information 

should it calculate backoff on a given channel and transmit the 

reservation message when the backoff is calculated to Zero, 

i.e. TXOP is obtained for the channel. The backoff calculation 

may be used, if the channel to be reserved is determined to be 

a primary channel of another BSS. With respect to a non 

primary channel, the reserving STA may be configured to 

transmit the reservation message after a determined duration 

that the media is detected to have been idle. This mode may be 

used if the channel is not known to be the primary channel of 

any other BSS. The time duration may be the PIFS, or it may 

be the PIFS plus one time slot. If the reserving STA is con 

figured to reserve only channels with which it does not need 

to use contention, e.g. no primary channels, the reserving 

STA may transmit reservation message(s) on channel(s) that 

it has detected to be free for the determined time duration. 

As mentioned above, the reserving STA may be configured 

to reserve a plurality of channels with a single reservation 

message. In such a case, if at least one of the channels com 

prises a primary channel and if at least one of the channels to 

be reserved is detected to be busy so that the reservation 

message cannot be transmitted on the plurality of channels, 

the reserving STA may decide not to transmit the reservation 

message. Furthermore, the reserving STA may be configured 

to reset the backoff value of the primary channel and recal 

culate a new TXOP for the primary channel, and to verify that 

the other channels to be reserved have been free for the 

determined time duration (e.g. PIFS). 

The TXOP holder may instruct a given reserving STA to 

reserve a plurality of additional channels or transmission 

bands, in which case the reserving device may be configured 

to reserve the channels in the order that they can be used in 

order to avoid unnecessary reservations. On the other hand, 

the reserving STA may be configured to reserve the channels 

in the order in which they become available for reservation to 

increase the probability that the plurality of channels are 

reserved within the TXOP. The TXOP holder may even assign 

a plurality of reserving STAs to reserve at least partly the 

same channels to further improve the probability that the 

channels will be reserved within the TXOP. For example, when the TXOP holder assigns the reserving STAs to reserve 

an additional 80 MHz band, it may configure plurality of 

Case 6:20-cv-00491-ADA Document 37 Filed 11/06/20 Page 12 of 18
US 8,730,905 B2 

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reserving STAs to reserve the same 80 MHz band each. In an 

embodiment, the TXOP holder may distribute the transmis 

sion band to be reserved to a plurality of sub-bands and assign 

the reserving STAs to reserve one of the sub-bands. For 

example, one reserving STA may be configured to reserve a 

Sub-band that is contiguous to the current transmission band 

of the TXOP, e.g. channels of a contiguous 80 MHz band (see 

2, 3, 4 in FIG. 1B) and another reserving STA may be con 

figured to reserve channels of the non-contiguous transmis 

sion band, e.g. non-contiguous band (see 5, 6 in FIG. 1B). The 

TXOP holder may then increase the transmission band in the 

order in which they may be used on the basis of received 

reservation response messages. 

Let us now consider the structure of the reservation request 

frame according to an embodiment of the invention. In an 

embodiment, the reservation request message is an individual 

frame. In another embodiment, the reservation request mes 

sage is comprised in another frame, e.g. a power-save multi 

poll (PSMP) frame of an IEEE 802.11 system. In an embodi 

ment where the TXOP holder transmits also other control 

messages or frames to other STAS of the BSS, e.g. organizing 

the STAs of the same BSS to protect the TXOP resources by transmitting reservation messages on primary channels of 

other BSSs that utilize channels overlapping with the TXOP 

resources, the reservation request message may be included 

in Such a control message or frame. The reservation request 

may be comprised in a very-high-throughput (V-HT) frame of 

IEEE 802.11ac, for example. The destination address of the 

reservation request message may be a group address or a 

dedicated address of an individual communication apparatus, depending on the number of reserving STAs instructed with 

Bit O 

Reservation to 

5 

10 

15 

25 

30 

primary CH 

of other BSS 

the reservation request message. Table 1 below illustrates an 

exemplary format of the reservation request message. 

TABLE 1. 

Order Information element 

1 Category 

2 Action 

3 to N Element 1 to N-2 

FIG. 10 illustrates an example of an Element of Table 1. As 

shown in Table 1, the reservation request message may com 

prise a plurality of elements of FIG. 10. A MAC address field 

(6 octets, for example) comprises a MAC address of a reserv 

ing STA designated by the TXOP holder to reserve the chan 

nel(s). In another embodiment, the MAC address field com 

prises the MAC address of the destination of the reservation 

message. If the destination address is set, the reserving STA 

may be configured to transmit the reservation message, e.g. a 

Request-to-Send (RTS), to the destination address, and a 

communication apparatus that is the destination may be con 

figured to acknowledge the RTS message with the CTS mes 

sage, for example. The TXOP holder may be configured to set 

the destination MAC address to comprise the MAC address of 

the AP that operates on the channel to be reserved. As a 

consequence, the NAV protection is propagated with the RTS/ 

CTS message transmitted by the AP throughout the coverage 

40 

45 

50 

55 

60 

65 

14 

area of the AP Field Report Time (2 octets, for example) 

specifies the duration from the end of the reservation request 

message frame to the transmission of the reservation response 

message. Field Report Channel (2 octets, for example) may 

define a channel on which the reservation response message is 

to be transmitted. Field Duration to Protect (2 octets, for 

example) sets the duration for the protection of the reserved 

channel. The value of the Duration to Protect field may be 

included in the reservation message transmitted by the reserv 

ing STA as such, or the reserving STA may reduce from the 

value of the Duration to Protect field a time duration that has 

lapsed from the reception of the reservation request message 

to a time instant when the reservation message is to be trans 

mitted. In an embodiment, the Duration to Protect field may 

be omitted, and the reserving STA may be configured to 

reserve the channel at least up to the transmission timing of 

the reservation response message instructed by the Report 

Time field. Options field (1 octet, for example) may define 

options with respect to the reservation. The reservation field 

may have a format as shown in Table 2 below. Field Channel 

ID 1 (2 octets, for example) may contain a channel number (or 

another channel identifier) of the primary channel of the other 

BSS to which the reservation message is transmitted first (see 

embodiment of FIG. 6). Field Channel ID 2 (2 octets, for 

example) may contain a channel number (or another channel 

identifier) of a channel included in a non-contiguous 80 MHz 

channel that is to be reserved (if such reservation is Sup ported). The channel identifier may identify the lowest chan 

nel, the highest channel, or a centre channel of the other 80 

MHz band, for example. 

TABLE 2 

Bit 1 Bit 2 Bit 3 Bit 4 Bit S Bits 6, 7 

CTS to Reserve Reserve Reserve Reserve non- Reserved 

legacy secondary tertiary quaternary contiguous STAS CH CH CH 80 MHz band 

Referring to Table 2 comprising elements of the options 

field of FIG. 10, bit 0 indicates whether or not the reservation 

message is transmitted on the primary channel of the other 

BSS (embodiment of FIG. 6). If this bit indicates that the 

reservation message should be transmitted on the primary 

channel of the other BSS, the reserving STA is configured to 

determine the channel identifier of the primary channel of the 

other BSS from the Channel ID1 field of FIG. 10. Bit 1 may be set to indicate that CTS messages used to reserve the 

channel should be transmitted in a format Supported by legacy 

802.11 devices, e.g. those not supporting IEEE 802.11ac but 

supporting IEEE 802.11a. Bit 2 indicates whether or not the 

reserving STA is configured to reserve the secondary channel. 

If a STA designated by the MAC header of the Element in 

question is assigned to reserve the secondary channel with a 

determined value of Bit 2, the STA is configured to carry out 

the reservation of the secondary channel as described above. 

Bit 3 indicates whether or not the reserving STA designated 

by the MAC header is configured to reserve the tertiary chan 

nel, and Bit 4 indicates whether or not the reserving STA 

designated by the MAC header is configured to reserve the 

quaternary channel. Similarly, Bit 5 indicates whether or not 

the reserving STA designated by the MAC header is config 

ured to reserve another 80 MHz band. If the BSS supports the 

channel allocation where the location of the other 80 MHz 

band is not fixed, the Channel ID2 field of FIG. 10 may be 

used to indicate a channel of the 80 MHz band, e.g. the lowest 

Case 6:20-cv-00491-ADA Document 37 Filed 11/06/20 Page 13 of 18
US 8,730,905 B2 

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or the highest channel on the 80 MHz band. On the other 

hand, if the BSS supports the channel allocation where the 

location of the other 80 MHz band is fixed, Channel ID2 may 

be omitted. 

With respect to FIG. 1 and Table 2 above, the lengths of the 

fields are merely exemplary, and other numbers of bits or 

octets may be used instead, depending on the implementa 

tion. 

The TXOP holder may be an access point or a terminal 

station of the BSS. Similarly, the reserving STAs may in 

practice comprise the access point and/or one or more termi 

nal stations of the BSS. The access point may determine the 

location of the primary channels of those other BSSs that have 

overlapping channels with the BSS of the access point 

(through channel sounding or reception of beacons from the 

other BSSs, for example), and transmit channel identifiers of 

the primary channels of the other BSSs as control signals in 

order to enable the reserving STAs to transmit the reservation 

messages on the primary channels of the other BSSs. The 

access point may also define protection levels for communi 

cation in the BSS. For example, the access point may control 

the utilization of the secondary, tertiary etc. channels by determining whether or not they are allowed to be used. In 

another embodiment, the access point sets a protection level 

for each channel. For example, the access point may define 

settings for NAV protection for each channel. By default, only 

the primary channel may be protected by the NAV setting, in 

which case the other channels are protected through CCA. 

However, the access point may set the NAV protection to 

other channels as well (secondary, tertiary etc.) to reduce the 

probability of collisions. The STAs may have a similar func 

tionality that is applied under the control of the access point or 

independently by each STA. 

In order for the reserving STA to benefit from the reserva 

tion it has made for the TXOP holder, the TXOP holder may 

be configured to use the TXOP as a multi-user TXOP which 

allows the TXOP holder to transmit data to multiple receivers 

during the TXOP. In this embodiment, the TXOP holder is 

configured to transmit in the same PPDU some of the data to 

initial receiver and some of the data to the reserving STA (not 

necessarily the initial receiver). Thus, the TXOP holder has 

more options to aggregate MAC PDUs and MAC Service 

Data Units (SDUs). 

The TXOP holder may process traffic to units, wherein 

each unit may be transmitted within a determined time inter 

val with a 20 MHz bandwidth. When additional bandwidth is 

reserved for the TXOP holder during the TXOP, the TXOP 

holder may easily increment the number of transmitted units 

according to the increased bandwidth, and the originally 

planned frame transmission at already reserved TXOP band 

width may be maintained without any modifications caused 

by the reservation of the additional bandwidth. The aggrega tion of the traffic into transmission units may be performed 

even before the TXOP starts and thus, the implementation specific real time requirements are relaxed. 

In some embodiments, the TXOP holder reserves the chan 

nels it needs to use in order to satisfy data transmission 

requirements, e.g. quality-of-service requirements. In other 

words, the TXOP holder does not necessarily always attempt 

the reserve all the channels of the BSS, while in some embodi 

ments the attempt to reserve all the channels may be default 

functionality. The TXOP holder may determine the transmis 

sion bandwidth that is actually needed based on channel 

estimation, transmission power reserves of the TXOP holder 

device, etc. 

The receiving STA may have established direct link with 

another STA in the network. The direct link enables the said 

5 

10 

15 

25 

30 

35 

40 

45 

50 

55 

60 

65 

16 

STAS to transmit and receive traffic between each other with 

out having an AP between them to forward frames. The said 

STAS may monitor the reservation requests and the reserving 

STA may use the reserved bandwidth to transmit frames in 

direct link before it notifies successful reservation to the 

TXOP holder. The direct link operation at the reserved chan 

nel improves the system efficiency. 

FIG. 11 illustrates an embodiment of an apparatus com 

prising means for carrying out the above-mentioned function 

alities of the TXOP holder and/or the reserving STA. The 

apparatus may be a communication apparatus of an IEEE 

802.11 network or another wireless network, e.g. an AP or 

STA. The communication apparatus may be a computer (PC), 

a laptop, a cellular phone, a palm computer, a fixed base 

station operating as the AP, or any other communication appa 

ratus. In another embodiment, the apparatus is comprised in 

Such a communication apparatus, e.g. the apparatus may comprise a circuitry, e.g. a chip, a processor, a micro control 

ler, or a combination of such circuitries in the communication 

apparatus. 

The apparatus may comprise a communication controller 

circuitry 10 configured to control the communications in the 

communication apparatus. The communication controller 

circuitry 10 may comprise a control part 14 handling control 

signaling communication with respect to transmission, recep 

tion, and extraction of control frames including the reserva 

tion request messages, reservation messages, and reservation 

response messages, as described above. The communication 

controller circuitry 10 may further comprise a data part 16 

that handles transmission and reception of payload data dur 

ing transmission opportunities of the communication appa 

ratus (transmission) or transmission opportunities of other 

communication apparatuses (reception). The communication 

controller circuitry 10 may further comprise a bandwidth 

decision circuitry 11 that determines transmission bandwidth 

for a transmission opportunity. The bandwidth decision cir 

cuitry 11 may be configured to adjust the transmission band 

width during the transmission opportunity upon reception of 

a signal notifying about increased bandwidth reservation for 

the transmission opportunity, as described above. In response 

to such a notification, the bandwidth decision circuitry 11 

may control the data part 16 to process new data packets Such 

that their transmission bandwidth is increased to cover ini 

tially and newly acquired transmission band(s). 

The communication controller circuitry 10 may further 

comprise a channel detection circuitry 12 configured to detect 

available channels. The channel detection circuitry 12 may be 

configured to tune the communication apparatus to scan for 

channels according to instructions comprised in a reservation 

request message received from a current TXOP holder, as 

described above. The channel detection circuitry 12 may be 

configured to monitor for a signal in the Scanned channel(s) 

for use as an input in the CCA. The channel detection circuitry 12 may also be configured to monitor for a message that 

triggers the NAV protection for the scanned channel(s). If 

either CCA or the NAV indicates that the channel contains 

transmissions, the channel detection circuitry 12 may be con 

figured to determine that the channel is not available for 

reservation. On the other hand, if the channel detection cir 

cuitry 12 detects no signals in the scanned channel during a 

determined time period (PIFS for example) and/or the NAV 

setting is not triggered, the channel detection circuitry 12 may 

be configured to control a channel reservation circuitry 13 

comprised in the communication controller circuitry 10 to 

reserve the channel(s) by transmitting any one of the above 

mentioned reservation messages on the channel(s) and/or on 

a primary channel of a BSS that was detected to transmit on 

Case 6:20-cv-00491-ADA Document 37 Filed 11/06/20 Page 14 of 18
US 8,730,905 B2 

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the channel(s). The location of the primary channel of the 

other BSS may be comprised in a memory unit 20. The 

channel detection circuitry 12 may also configured the con 

trol part 14 to transmit the reservation response message 

according to any one of the above-mentioned embodiments to 

the TXOP holder. The control part may then be configured to 

transmit the reservation response message by using default 

transmission parameters and/or transmission parameters 

included in the reservation request message received from the 

TXOP holder, as described above. 

The circuitries 11 to 16 of the communication controller 

circuitry 10 may be carried out by the one or more physical 

circuitries or processors. In practice, the different circuitries 

may be realized by different computer program modules. 

Depending on the specifications and the design of the appa 

ratus, the apparatus may comprise Some of the circuitries 11 

to 13 or all of them. For example, an embodiment of the 

apparatus is configured to request another communication 

apparatus to reserve communication resources, but the appa 

ratus itself does not support reservation of communication 

resources for the other communication apparatus. In this 

embodiment, circuitries 12 and 13 may be omitted. In another 

embodiment, the apparatus is configured to reserve additional 

transmission band(s) for another communication apparatus 

but is itself configured to use the same transmission band for 

the duration of the transmission apparatus. In this case, the 

bandwidth decision circuitry 11 may be omitted or modified 

accordingly. 

The apparatus may further comprise the memory 20 that 

stores computer programs (Software) configuring the appara 

tus to perform the above-described functionalities of the com 

munication device. The memory 20 may also store commu 

nication parameters and other information needed for the 

wireless communications. The memory 20 may also store a 

database storing the primary channels of neighboring BSSs, 

channel utilization rules of the BSS, and/or other channel 

information, as described above. The apparatus may further 

comprise radio interface components 30 providing the appa 

ratus with radio communication capabilities within the BSS 

and with other BSSs. The radio interface components 30 may comprise standard well-known components such as ampli 

fier, filter, frequency-converter, (de)modulator, and encoder/ 

decoder circuitries and one or more antennas. The apparatus 

may further comprise a user interface enabling interaction 

with the user of the communication device. The user interface 

may comprise a display, a keypad or a keyboard, a loud 

speaker, etc. 

In an embodiment, the apparatus carrying out the embodi 

ments of the invention in the communication apparatus com 

prises at least one processor and at least one memory includ 

ing a computer program code, wherein the at least one 

memory and the computer program code are configured, with 

the at least one processor, to cause the apparatus to carry out 

the steps of the process of FIG. 2. In further embodiments, the 

at least one memory and the computer program code are 

configured, with the at least one processor, to cause the appa 

ratus to carry out any one of the embodiments related to 

acquiring additional transmission band for the TXOP holder, as described above in connection with FIGS. 2 to 10. Accord 

ingly, the at least one processor, the memory, and the com 

puter program code form processing means for carrying out 

embodiments of the present invention in the wireless com 

munication apparatus. 

As used in this application, the term “circuitry refers to all 

of the following: (a) hardware-only circuit implementations, 

Such as implementations in only analog and/or digital cir 

cuitry, and (b) to combinations of circuits and Software (and/ 

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55 

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or firmware). Such as (as applicable): (i) a combination of 

processor(s) or (ii) portions of processor(s)/software includ 

ing digital signal processor(s), software, and a memory or 

memories that work together to cause the apparatus to per 

form various functions, and (c) to circuits, such as a micro 

processor(s) or a portion of a microprocessor(s), that require 

software or firmware for operation, even if the software or 

firmware is not physically present. This definition of cir 

cuitry applies to all uses of this term in this application. As a 

further example, as used in this application, the term “cir 

cuitry would also cover an implementation of merely a pro 

cessor (or multiple processors) or a portion of a processor and 

its (or their) accompanying Software and/or firmware. The 

term “circuitry” would also cover, for example and if appli 

cable to the particular element, a baseband integrated circuit 

or applications processor integrated circuit for a mobile 

phone or a similar integrated circuit in server, a cellular net 

work device, or other network device. 

The processes or methods described in connection with 

FIGS. 2 to 10 may also be carried out in the form of a 

computer process defined by a computer program. The com 

puter program may be in source code form, object code form, 

or in some intermediate form, and it may be stored in some 

sort of carrier, which may be any entity or device capable of 

carrying the program. Such carriers include a record medium, 

computer memory, read-only memory, electrical carrier sig 

nal, telecommunications signal, and software distribution 

package, for example. Depending on the processing power 

needed, the computer program may be executed in a single 

electronic digital processing unit or it may be distributed 

amongst a number of processing units. 

The present invention is applicable to wireless telecommu 

nication systems defined above but also to other suitable 

telecommunication systems. The protocols used, the specifi 

cations of mobile telecommunication systems, their network 

elements and subscriber terminals, develop rapidly. Such 

development may require extra changes to the described 

embodiments. Therefore, all words and expressions should be 

interpreted broadly and they are intended to illustrate, not to 

restrict, the embodiment. It will be obvious to a person skilled 

in the art that, as technology advances, the inventive concept 

can be implemented in various ways. The invention and its 

embodiments are not limited to the examples described above 

but may vary within the scope of the claims. 

The invention claimed is: 

1. A method, comprising: 

acquiring, in a first wireless communication apparatus, a 

transmission period to transmit data on a first frequency 

band within a determined transmission time interval, 

wherein the transmission period is a transmission oppor tunity for a wireless local area network; 

determining to utilize a bandwidth greater than that of the 

first frequency band during the transmission period; 

causing transmission of a reservation request message to at 

least second wireless communication apparatus, wherein the reservation request message instructs the 

second wireless communication apparatus to reserve at 

least one additional frequency band for the first wireless 

communication apparatus during the transmission 

period; 

receiving a reservation response message from the at least 

second wireless communication apparatus, wherein the 

reservation response message indicates that said at least 

one additional frequency band is available for the first 

wireless communication apparatus to use in transmis 

sion during the transmission period; and 

Case 6:20-cv-00491-ADA Document 37 Filed 11/06/20 Page 15 of 18
US 8,730,905 B2 

19 

in response to the reception of the reservation response 

message, increasing a transmission band to comprise 

both said first frequency band and said at least one addi 

tional frequency band during the transmission period 

thereby transmitting data on the transmission band hav 

ing the increased bandwidth greater than that of the first 

frequency band. 

2. The method of claim 1, further comprising: causing the 

transmission of the reservation request message at the begin 

ning of the transmission period. 

3. The method of claim 1, further comprising: causing transmission of data only on the first frequency 

band until the reservation response message is received 

during the transmission period; and 

causing transmission of data on the first frequency band 

and on the at least one additional frequency band after 

the reservation response message is received during the 

transmission period. 

4. The method of claim 1, further comprising receiving the 

reservation response message during a time interval between 

data transmission intervals during the transmission period. 

5. The method of claim 1, wherein the reservation request 

message comprises an identifier of the second wireless com 

munication apparatus, and at least one frequency channel 

indicatorindicating the at least one additional frequency band 

that is to be reserved by the second wireless communication 

apparatus. 

6. A method, comprising: 

receiving, from a first wireless communication apparatus 

in a second communication apparatus, a reservation 

request message instructing the second wireless com 

munication apparatus to reserve at least one additional 

frequency band for the first wireless communication 

apparatus during a transmission period of the first wire 

less communication apparatus, the at least one addi 

tional frequency band being requested for use by the first 

wireless communication apparatus while transmitting 

data on a first frequency band, wherein the transmission 

period is a transmission opportunity for a wireless local 

area network; 

monitoring for availability of the at least one additional 

frequency band during the transmission period of the 

first wireless communication apparatus: in response to detection of availability of the at least one 

additional frequency band during the transmission 

period of the first wireless communication apparatus, causing transmission of a reservation response message 

to the first wireless communication apparatus, wherein 

the reservation response message indicates that said at 

least one additional frequency band is available for the 

first wireless communication apparatus to use in trans 

mission during the transmission period of the first wire 

less communication apparatus to enable the first wire 

less communication apparatus to increase the bandwidth 

of transmission to comprise the first frequency band and 

the at least one additional frequency band so that the first 

wireless communication apparatus transmits data dur 

ing the transmission period on a transmission band hav 

ing increased bandwidth greater than that of the first 

frequency band. 

7. The method of claim 6, further comprising: causing, in 

the second wireless communication apparatus, transmission 

of a reservation message reserving the at least one frequency 

band by triggering a network allocation vector setting to the 

reserved at least one frequency band. 

8. The method of claim 7, wherein the reservation message is a clear-to-send message. 

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30 

35 

40 

45 

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55 

60 

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9. The method of claim 7, wherein second wireless com 

munication apparatus is requested to reserve a plurality of 

frequency bands, the method further comprising causing the 

transmission of the reservation message on each frequency band separately. 

10. The method of claim 6, further comprising: receiving, in the reservation request message, transmission 

parameters related to transmission of the reservation 

response message; and 

transmitting the reservation response message according to 

the received transmission parameters. 

11. The method of claim 10, wherein the transmission 

parameters relate to at least one of timing and transmission 

frequency of the reservation response message. 

12. An apparatus comprising: 

at least one processor, and 

at least one memory including a computer program code, 

wherein the at least one memory and the computer pro 

gram code are configured, with the at least one proces 

Sor, to cause the apparatus to: 

acquire a transmission period to transmit data on a first 

frequency band within a determined transmission time 

interval, wherein the transmission period is a transmis 

sion opportunity for a wireless local area network; 

determine to utilize a bandwidth greater than that of the 

first frequency band during the transmission period; 

cause transmission of a reservation request message from a 

first wireless communication apparatus to at least a sec 

ond wireless communication apparatus, wherein the res 

ervation request message instructs the second wireless 

communication apparatus to reserve at least one addi 

tional frequency band for the first wireless communica 

tion apparatus during the transmission period; 

receive a reservation response message from the at least 

second wireless communication apparatus, wherein the 

reservation response message indicates that said at least 

one additional frequency band is available for the first 

wireless communication apparatus to use in transmis 

sion during the transmission period; and 

in response to the reception of the reservation response 

message, cause the first wireless communication appa 

ratus to increase a transmission band to comprise both 

said first frequency band and said at least one additional 

frequency band during the transmission period thereby 

transmitting data on the transmission band having the 

increased bandwidth greater than that of the first fre 

quency band. 

13. The apparatus of claim 12, wherein the at least one 

memory and the computer program code are configured, with 

the at least one processor, to cause the apparatus to cause the 

transmission of the reservation request message at the begin ning of the transmission period. 

14. The apparatus of claim 12, wherein the at least one 

memory and the computer program code are configured, with 

the at least one processor, to cause the apparatus to: 

cause transmission of data only on the first frequency band 

until the reservation response message is received dur 

ing the transmission period; and 

cause transmission of data on the first frequency band and 

on the at least one additional frequency band after the 

reservation response message is received during the 

transmission period. 

15. The apparatus of claim 12, wherein the at least one 

memory and the computer program code are configured, with 

the at least one processor, to cause the apparatus to receive the 

reservation response message during a time interval between 

data transmission intervals during the transmission period. 

Case 6:20-cv-00491-ADA Document 37 Filed 11/06/20 Page 16 of 18
message is a clear-to-send message. 

US 8,730,905 B2 

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16. The apparatus of claim 12, wherein the reservation 

request message comprises an identifier of the second wire 

less communication apparatus, and at least one frequency 

channel indicator indicating the at least one additional fre 

quency band that is to be reserved by the second wireless 5 

communication apparatus. 

17. The apparatus of claim 12, wherein the apparatus fur 

ther comprises radio interface components enabling the appa 

ratus to access a radio medium. 

18. An apparatus, comprising: 10 

at least one processor; and 

at least one memory including a computer program code, 

wherein the at least one memory and the computer pro 

gram code are configured, with the at least one proces 

Sor, to cause the apparatus to: 

cause reception of a reservation request message from a 

first wireless communication apparatus the reservation 

request message instructing the apparatus to reserve at 

least one additional frequency band for the first wireless 

communication apparatus during a transmission period 

of the first wireless communication apparatus, the at 

least one additional frequency band being requested for 

use by the first wireless communication apparatus while 

transmitting data on a first frequency band, wherein the 

transmission period is a transmission opportunity for a 

wireless local area network; 

monitor for availability of the at least one additional fre 

quency band during the transmission period of the first 

wireless communication apparatus; in response to detection of availability of the at least one 

additional frequency band during the transmission 

period of the first wireless communication apparatus, 

cause transmission of a reservation response message to 

the first wireless communication apparatus, wherein the 

reservation response message indicates that said at least 

one additional frequency band is available for the first 

wireless communication apparatus to use in transmis 

sion during the transmission period of the first wireless 

communication apparatus to enable the first wireless 

communication apparatus to increase the bandwidth of 

transmission to comprises the first frequency band and 

the at least one additional frequency band so that the first 

wireless communication apparatus transmits data dur 

ing the transmission period on a transmission band hav 

ing increased bandwidth greater than that of the first 

frequency band. 

19. The apparatus of claim 18, wherein the at least one 

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memory and the computer program code are configured, with 

the at least one processor, to cause the apparatus to cause 

transmission of a reservation message reserving the at least 

one frequency band by triggering a network allocation vector 

setting to the reserved at least one frequency band. 

50 

20. The apparatus of claim 19, wherein the reservation 55 

21. The apparatus of claim 19, wherein the apparatus is 

requested to reserve a plurality of frequency bands, wherein 

the at least one memory and the computer program code are 

configured, with the at least one processor, to cause the appa 

ratus to cause the transmission of the reservation message on 

each frequency band separately. 

60 

22. The apparatus of claim 18, wherein the at least one 

memory and the computer program code are configured, with 

the at least one processor, to cause the apparatus to: 

receive, in the reservation request message, transmission 

parameters related to transmission of the reservation 

response message; and 

65 

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cause transmission of the reservation response message according to the received transmission parameters. 

23. The apparatus of claim 22, wherein the transmission 

parameters relate to at least one of timing and transmission 

frequency of the reservation response message. 

24. The apparatus of claim 18, wherein the apparatus fur 

ther comprises radio interface components enabling the appa 

ratus to access a radio medium. 

25. A computer program product comprising a non-transi 

tory computer-readable storage medium bearing computer 

program code embodied therein for use with a computer, the 

computer program code comprising: 

code for acquiring a transmission period for a first wireless 

communication apparatus to transmit data on a first fre 

quency band within a determined transmission time 

interval, wherein the transmission period is a transmis 

sion opportunity for a wireless local area network; 

code for determining to utilize a bandwidth greater than 

that of the first frequency band during the transmission 

period; 

code for causing transmission of a reservation request mes 

Sage from the first wireless communication apparatus to 

at least second wireless communication apparatus, wherein the reservation request message instructs the 

second wireless communication apparatus to reserve at 

least one additional frequency band for the first wireless 

communication apparatus during the transmission 

period; 

code for receiving a reservation response message from the 

at least second wireless communication apparatus, wherein the reservation response message indicates that 

said at least one additional frequency band is available 

for the first wireless communication apparatus to use in 

transmission during the transmission period; and 

code for, in response to the reception of the reservation 

response message, increasing a transmission band to 

comprise both said first frequency band and said at least 

one additional frequency band during the transmission 

period thereby transmitting data on the transmission 

band having the increased bandwidth greater than that of 

the first frequency band. 

26. A computer program product comprising a non-transi 

tory computer-readable storage medium bearing computer 

program code embodied therein for use with a computer, the 

computer program code comprising: 

code for causing reception of a reservation request message 

from a first wireless communication apparatus the res 

ervation request message instructing the apparatus to 

reserve at least one additional frequency band for the 

first wireless communication apparatus during a trans 

mission period of the first wireless communication 

apparatus, the at least one additional frequency band 

being requested for use by the first wireless communi 

cation apparatus while transmitting data on a first fre 

quency band, wherein the transmission period is a trans 

mission opportunity for a wireless local area network; 

code for monitoring for availability of the at least one 

additional frequency band during the transmission 

period of the first wireless communication apparatus; 

code for, in response to detection of availability of the at 

least one additional frequency band during the transmis 

sion period of the first wireless communication appara 

tus, causing transmission of a reservation response mes 

Sage to the first wireless communication apparatus, 

wherein the reservation response message indicates that 

said at least one additional frequency band is available 

for the first wireless communication apparatus to use in 

Case 6:20-cv-00491-ADA Document 37 Filed 11/06/20 Page 17 of 18
US 8,730,905 B2 

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transmission during the transmission period of the first 

wireless communication apparatus to enable the first 

wireless communication apparatus to increase the band 

width of transmission to comprise the first frequency 

band and the at least one additional frequency band so 

that the first wireless communication apparatus trans 

mits data during the transmission period on a transmis 

sion band having increased bandwidth greater than that 

of the first frequency band. k k k k k 10 

24 

Case 6:20-cv-00491-ADA Document 37 Filed 11/06/20 Page 18 of 18