IN THE UNITED STATES PATENT AND TRADEMARK OFFICE
`
`In re Patent of: Webster et al.
`U.S. Patent No.: 6,754,195
`Issue Date:
`June 22, 2004
`Appl. Serial No.: 10/143,134
`Filing Date:
`May 10,2002
`Title:
`WIRELESS COMMUNICATION SYSTEM CONFIGURED TO
`COMMUNICATE USING A MIXED WAVEFORM CONFIGURATION
`
`Attorney Docket No.: 27410-0021IP2
`
`DECLARATION OF PAULA CAREY
`
`I, Paula Carey, declare that:
`
`1.
`
`I am the Mathematics and Engineering Librarian at the Boston University
`
`Libraries (the "Library"). I make this declaration of my own personal knowledge.
`
`2.
`
`3.
`
`4.
`
`I have been employed with the Library for approximately 36 years.
`
`I am not and have not been affiliated with Marvell Semiconductor Inc.
`
`During the period of December 2000 to March 2001, I was the Mathematics and
`
`Engineering Librarian and I have personal knowledge of the Library's normal practices for
`
`recording the receipt of and cataloguing and shelving of conference proceedings received by the
`
`Library during December 2000 to March 2001.
`
`5.
`
`The normal practice of the Library is to enter information regarding conference
`
`proceedings into the Library's database. After a conference proceeding is received at the
`
`Library, a catalogue record for the conference proceeding is entered into the Library's database.
`
`Once a conference proceeding appears as a catalogue record in the Library's database, patrons of
`
`the Library can search for and find the conference proceeding, and can request a physical copy of
`
`the conference proceeding from the Library, even if it is not yet placed on a Library shelf. The
`
`Page 1 of 3
`
`

`
`Library's normal practice of entering catalogue records in the Library's database was generally
`
`the same during December 2000 to March 2001 as it is today.
`
`6.
`
`Once a catalogue record for a conference proceeding has been entered into the
`
`Library's database, the normal practice of the Library is to send the conference proceeding to a
`
`particular library location within the Library for physical shelving.
`
`7.
`
`Attached hereto as Exhibit A is a true and correct copy of"An Adaptive Multirate
`
`IEEE 802.11 Wireless LAN" by Jean-Lien C. Wu et al., Information Networking,
`
`2001, Proceedings, 15th International Conference, pages 411-418, Jan. 31- Feb. 02,2001,
`
`IEEE, 2001 (Print ISBN 0-7695-0951-7) (hereinafter the "Wu reference").
`
`8.
`
`Attached hereto as Exhibit B is a screen shot of a computer display showing the
`
`catalogue record in the Library's database for the Wu reference.
`
`9.
`
`Exhibit B shows that the catalogue record for the Wu reference was entered into
`
`the Library's database on March 12, 2001, at which time patrons of the Library could have
`
`searched for, found, and requested a physical copy of the Wu reference, even if it was not yet
`
`placed on a Library shelf.
`
`Page 2 of3
`
`

`
`10.
`
`I declare under penalty of perjury under the laws of the United States of America
`
`that the foregoing is true and correct.
`
`I hereby declare that all statements made herein ofmy own
`
`knowledge are true and that all statements made on information and belief are believed to be
`
`true; and further that these statements were made with the knowledge that willful false
`
`statements and the like so made are punishable by fine or imprisomnent, or both, under Section
`
`1001 of Title 18 of the United States Code.
`
`Executed on: March _‘J_, 2015
`
`
`
`U/6&1
`
`
`Pa la Carey
`Mathematics and Engineering Libraiian
`Boston University Science and Engineering Library
`38 Cummington Mall
`Boston, MA 02215
`
`Page 3 of3
`
`

`
`EXHIBIT A
`EXHIBIT A
`
`

`
`An Adaptive Multirate IEEE 802.11 Wireless LAN
`
`Jean-Lien C. Wu, Hung-Huan Liu, and Yi-Jen Lung
`Department of Electronic Engineering
`National Taiwan University of Science and Technology
`43, Keelung Road, Section 4, Taipei, Taiwan, R.O.C. 106
`Email: jcw@et.ntust.edu.tw
`
`Abstract
`
`In order to f!llhance the system capacity of wireless
`l.ANs, we propose in this paper using the frame -based
`adaptive multirgte transmission scheme in
`the IEEE
`802.11
`and
`evaluate
`its performance.
`1)•pically,
`high-speed mod11lation schemes would require higher SNR
`to maintain the transmission quality and BER. The
`transmission rate is selected d)'namicallv based on the
`detected SNR, each frame sh~/1 be tra;1smitted at the
`highest available rate. The original virtual carrier sense
`mechanism in 1/:N~E 802.11 is no longer suitable because
`the multirate hidden terminal problem. We redefine the
`MAC header qnd modify the reservation scheme of tile
`network al/ocmiqn vector (NAV) ro resolve these problems.
`The throughput and delay are evaluated using simulations
`and the result.£ show that they can be significantly
`improved compared with those of the single-rate WLAN.
`
`Keywords: IEEE 802.11, Wl.AN, adaptive multirate,
`hicj4i!n terminal problem, carrier sense
`
`1. Introduction
`
`The IEEE 802.11 WLAN standard was approved on
`June 1997 [ 1] and the first edition of new IEEE 802.11
`standard has b&;:~n published in 1999 [2] with data rates of
`I and 2 Mbps. In order to provide high bandwidth to users,
`several drafts ar(.l proposed to provide high-rate extension
`of the PHY layer [3] . The high-rate PHY extension for the
`is
`direct seque~cc: spread spectrum (DSSS) system
`specified in
`!h<; 2.4 GHz band designated for ISM
`applications [4) , This extension of the DSSS system builds
`on the data rate capabilities to provide 5.5 and 11 Mbps
`payload data f!ltt:s in addition to the I and 2 Mbps. The
`is
`the orthogonal
`frequency-division
`other selection
`multiplexing (OfDM) as the basis for the new 50Hz
`
`• This research W:\!; ~ up ported by National Science Council of the
`Republic of Chin~. under grnnr NSC 89-2213·E-O 11-092
`
`standard, targeting a range of data rates from 6 up to 54
`Mbps [5].
`By using the concept of adaptive modulation [6],
`mobile stations
`in a multirate WLAN assign
`the
`modulation scheme and transmission rate according to the
`detected signal-to-noise ratio (SNR) and the required
`transmission quality. Each modulation scheme could be
`further mapped to a range of SNR in a given transmission
`power. To achieve high transmission efficiency in WLANs,
`stations shall select the highest available rate modulation
`scheme according to the detected SNR.
`The IEEE 802.IJ [2] and IEEE 802.1lb [4] WLANs
`apply the multirate concept by providing different rates
`according to the detected SNR. In the indoor environment
`using the IEEE 802. t 1 b compliant product, transmission
`distances for 2, 5.5, and l!Mbps are recommended as 75,
`45, and 30 meter [7], respectively. However, in these
`schemes transmission rate is selected apriori, e.g. 5.5Mbps
`for the range of 45 meter, even though the receiver and
`transmitter are close to each other and the detected SNR is
`better, the transmission rate could not be changed.
`We consider in this paper the multirate scheme where
`transmission
`rate of each
`the
`frame
`is
`selected
`dynamically based on the detected SNR of the previous
`transmission/reception but not on a predetermined rate.
`This scheme performs a better data throughput using the
`distributed coordination function (DCF). Stations could
`establish communication sessions with each other without
`the coordination overhead of an Access Point (AP). All
`stations and the AP must have the capability to select the
`proper transmission rate dynamically. The MAC function
`should be modified to handle different transmission rates
`and overcome the hidden terminal problem . .
`In the next section, the IEEE 802.11 WLAN and IEEE
`802.11 b high-rate WLAN are presented. In section 3, the
`is presented. In
`proposed adaptive multirate WLAN
`section 4, the simulation model and results are discussed
`and compared.
`
`0-7695·0951-7/01 $10.00 © 2001 IEEE
`
`411
`
`

`
`2. The IEEE 802.11 wireless LAN
`
`the
`is
`The DCF, also known as CSMNCA,
`fundamental access method of the IEEE 802.11 MAC
`used to support asynchronous data cransfer on a best-effort
`basis and is implemented in all stations to use in the
`WLAN environment. The DCF could operate solely in the
`ad hoc network and operate either solely or coexist with
`the PCF in an infrastructure network [8-10].
`The carrier sense is performed both by the physical
`carrier sense mechanism at the air interface and the virtual
`carrier sense mechanism at the MAC sublayer. The
`exchange of request-to-send (RTS) and clear-to-send
`(CTS) frames performs both a type of fast collision
`transmission path check. Another
`inference and a
`advantage of the RTS/CTS mechanism is to avoid the
`hidden terminal (HT) problem. The network allocation
`vector (NAV) of each station maintains a prediction of a
`future traffic on the medium based on the duration/ID
`field which specifies the total duration of the next
`fragment and acknowledge, and is available in the MAC
`headers of all frames sent under the DCF. The IEEE
`802.11 WLAN uses the NAV and its update mechanism to
`inhibit the hidden
`terminal to
`transmit frame while
`channel busy, and this mechanism is so called virtual
`
`carrier sense. Large MAC service data ·units (MSDUs)
`handed down from the LLC to the MAG may require
`fragmentation to increase transmission reliability. The
`exchange of RTS/CTS frames and the upd~te of the NAV
`are illustrated briefly in Fig. 2.
`
`2.1. High-rate WLAN
`
`Several high-rate specifications aiil designed
`to
`provide higher transmission rate for fufufe WLANs. In
`July 1998, the IEEE 802.11 b working group adopted the
`complementary code keying (CCK) as the basis for the
`high rate PHY exlension to deliver data up tb 11Mbps [4].
`The extension of the DSSS system builds ail the data rate
`capabilities to provide 5.5 and 11 Mbps pilyioad data rates
`in addilion to the I and 2 Mbps for thi: 2.4 GHz and
`designated for ISM applications. Four mociuiation formats
`and data rates are specified for che high-rate DSSS
`(HRIDSSS). The basic access rate includes I Mbps based
`on differential binary phase shift keying {DBPSK) and 2
`Mbps based on differential quaternary phase shift keying
`(DQPSK). The enhanced HR/DSSS specification defines
`two additional data rates 5.5 and II MIJpli based on the
`DQPSK and CCK modulation mode [11-1.5].
`A physical layer convergence function Is supported by
`
`DIFS
`
`SIFS
`
`SIFS
`
`SIFS
`
`Source
`
`Destination
`
`Other
`
`NAY(RTS)
`
`NAY (Frag. 0)
`
`NAY(CTS)
`
`NAY (AckO)
`
`:r;.;i
`
`Defer access
`
`Figure 1. RTS/CTS with fragmented MSDU
`
`I Mbii/JDBPSK
`
`PPDU:PHY Protocol D<Ua Unit
`
`Figure 2. Long PPDU format.
`
`Figure 3. Short PPDU formaL
`
`412
`
`

`
`the physical l;iyt;;r convergence procedure (PLCP) and
`defines a method of mapping the MAC sublayer into a
`framing suitab1~ for sending and receiving user data and
`management infqrmation between two or more stations. In
`the IEEE 80~ , I I b standard, the PLCP preamble and
`header depicted in Fig .. 2 shall be transmitted using the I
`Mbps barker gp(le spreading with DBPSK modulation.
`The PHY service data unit (PSDU) shall be transmitted
`using 1, 2, 5.5, and 11 Mbps. In order to optimize the
`network data t!lroughput and minimize the overhead, a
`shorter PLCP preamble and header [4] can be used, as
`shown in Fig, 3. The short PLCP preamble shall be
`transmitted usiog the 1Mbps barker code spreading with
`DBPSK modulation scheme and the short PLCP header
`the 2Mbps barker code
`shall be
`transmitted using
`spreading with DQPSK.
`indicates to the PHY the
`The PLCP ~ignal field
`modulation which shall be used for transmission of the
`PSDU. The high· rate PHY supports four mandatory rates
`1, 2, 5.5, and 11 Mbps. However, HRIDSSS/short supports
`three mandatory rates from 2, 5.5, and I lMbps. In the
`PLCP service field, the modulation mode selection bit
`shall be used to indicate whether the modulation mode is
`CCK or packet binary convolutional coding (PBCC).
`
`3. The propQ~ed adaptive multirate WLAN
`
`the virtual
`transmission scheme,
`the m11llirate
`In
`carrier sense scheme in the MAC layer may fail due to
`decoding error, In general, higher data rate modulation
`requires higher SNR to maintain the transmission quality.
`It is assumed th!!l the transmitted power is the same for all
`data rates, and the physical carrier sense scheme is the
`same as that of tile single rate WLAN. That is, stations can
`the phy$ical channel busy or idle. However,
`detect
`decoding error- may occur in the MAC layer when the
`station is neither a transmitter nor a receiver but falling
`the d~coding region, while
`the
`transmitter
`outside
`transmits frames using high·rate modulation. The station,
`jam
`ihe
`terminal, may
`thus becoming a hidden
`transmission. This case occurs in station C of Fig. 4 where
`
`Station C may jam the transmission when station B sends
`an ACK frame back to station A due to the decoding error
`in the previous frame transmitted from station A to B.
`Another problem in the original virtual carrier sense
`scheme is that the mobile stations does not know the
`transmission rate of the next frame and cannot properly
`reserve the NAY in the current transmission.
`In our proposed rnultirate scheme, the HRIDSSS/short
`system is considered with three data rates, 2, 5.5, and I 1
`Mbps, which is selected dynamically for each MSDUs.
`All control frames, includes RTS, CTS, and ACK frame,
`should be transmitted at basic data rate set in the multirate
`WLAN. In this paper, 2Mbps is suggested for the basic
`data rate.
`The multirate IEEE 802.1 I WLAN can be operated
`using the soft radio concept and the capability of channel
`estimation[ 16,17] and
`the function blocks of mobile
`stations are depicted in Fig. 5. We propose to use a pseudo
`NAY, denoted by NAVp, which maintains the value of the
`whole duration of an MSDU at 2Mbps, the basic rate, as
`an auxiliary to solve the problem. The duration/ID field in
`the MAC header of each data/ACK frame is the time
`interval that the frame is transmitted at the· selected rate
`and at the basic rate. A set of modified MAC transmission
`procedure and the modified NAY reservation scheme are
`provided as follows:
`
`[Transmitter (Station A In Fig. 4): I
`Upon a new MSDU arrival and the channel is detected idle, aFter the
`physical and vinual carrier sense.
`If MSDU length < RTS threshold Then
`send the MSDU as the original protocol at the selected
`rate.
`
`Else
`set the duration/ID field in MAC header as the whole
`duration of an MSDU;
`
`Range of B 's lransmiucr
`
`Figure 4. An ~)(ample of a failure in the virtual carrier
`sense .scheme.
`
`Figure 5. The system block of a multirate mobile
`station
`
`413
`
`

`
`send RTS frame at 2Mbps;
`having received an ACK, send the data frame at the
`sekected rate; (the duratuin!ID field in the MAC
`header is set to the time interval that the frame is
`transmitted at the selected rate and at the basic
`rate)
`
`Endlf
`
`[Receiver (Station B in Fig. 4):]
`If a single data frame is received Then
`.operate as the original protocol;
`Else If an RTS frame is received Then
`extract the value of the duration!ID field in MAC
`header, set the NAVP; ·
`set the duration!ID filed in the ACK frame as the whole
`duration of an MSDU;
`send back the ACK frame at 2Mbps;
`EndlfEndlf
`If a data frame is received Then
`extract the value of the duration!ID field (n) in MAC
`header;
`set NAVP = NAVp- n;
`send back the ACK frame;
`Else If channel idle Then
`wait for SIFS+SIFS, destroy the NAVP;
`(the NAVP
`broadcast a NAVP cancellation frame;
`cancellation frame does not be defined in the
`original standard)
`EndlfEndlf
`
`[Transmitter side stations (Station C in Fig. 4):]
`If a single data frame is received Then
`as the original protocol.
`Else If an RTS frame is received Then
`extract the value of the duration field in MAC header,
`setNAVp;
`EndlfEndlf
`If a data frame is received Then
`If the PSDU can be decoded Then
`extract the value of the duration!ID field in MAC
`header;
`set NAVP = NAVP- n;
`Else
`extract the values of the signal (r) and length (f) field in
`PHY header;
`set NAVP = NAVP- l(r-2)/r;
`End If
`Else If channel idle Then
`wait for 2SIFS+ACK+SIFS, destroy the NAVP;
`EndlfEndlf
`
`(Upon a new MSDU arrival:)
`If the channel is idle and the NAVp expires Then
`the transmission procedure starts;
`Else
`
`inhibit transmission until NAVP expires;
`End If
`
`[Receiver side stations (Station Din Fig, 4):]
`If aCTS frame is received Then
`extract the value of the duration field in MAC header,
`setNAVP;
`End If
`If an ACK frame is received Then
`extract the value of the duration!ID field (n) in MAC
`header;
`set NAVP = NAVp- n;
`End If
`If a NAVp cancellation frame is received 'then
`destroy the NAVP;
`End If
`
`4. Simulations
`
`the
`simulate
`to
`is used
`simulation
`Computer
`performance of the proposed multirate WLAN. Consider
`the premise of the same coverage range, a single-rate
`WLAN based on 2 Mbps data rate and a multi rate WLAN
`based on three data rates are compared, These two kinds
`of WLANs are modeled in the HR/DSS$/short system.
`The adaptive multirate WLAN uses three data rates, 2
`Mbps, 5.5Mbps, and II Mbps. StatioM and the AP
`communicate directly with each other under the DCF.
`
`4.1. System model
`
`Both in an infrastructure network and an ad hoc
`network are studied using the adaptive miJJtirate WLAN.
`In an infrastructu~e network, an AP is losated in the center
`of a single BSS, stations are randomly located inside a
`BSS. If direct communication between stations is not
`possible, it could be transmitted through iu'i AP. The traffic
`load from an AP is heavier than that from a station in an
`infrastructure network because of the heaVier download in
`the Internet. The probability of traffic liliid from an AP is
`assumed to be p and that from stations is 1-p. The traffic
`load in each station is assumed to be tbe same. Stations
`and the AP in a WLAN generate asynchronous data traffic
`from the upper layers to the MAC lay~f following the
`Poisson distribution.
`Assume that there is no interference frem neighboring
`BSSs, no overlaid in a multicell environment [15] and
`capture effect is negligible. Assume that the propagation
`delay is negligible. For the performance estimation under
`heavy load condition, an infinite queue betWeen the upper
`and the MAC layer is assigned in each station and the AP
`so that no packet will be dropped, but the number of
`retransmissions may exceed the threshoid of the short
`retry count or the long retry count.
`
`414
`
`

`
`Attribute v~tlues of the IEEE 802.11 WLAN are given
`in Table I. Th~ aFragThresho/d attribute is used to
`combat the effects of poor channel quality. However,
`fragmentations reduce the aggregate throughput because
`of the associat~g overhead and the length of an MSDU
`also affects th~:~ performance. Crow et al. (8] showed the
`optimum value 9f the aFragThreshold attribute between
`500 and 800 oct!ltS tradeoffs the average MSDU length. ·
`The 800 octets aFragThreshold and 1000 octets average
`MSDU length \l~ed in our simulation model are extracted
`from [8,18]. ·
`Several companies have implemented IEEE 802 .. 11 b
`WLAN prodQcts
`[7].
`In
`the
`indoor environment,
`transmission ~istances for 2, 5.5, and
`l!Mbps are
`recommended a~ 75 meter, 45 meter, and 30 meter,
`respectively[7], Well-defined coverage areas do not exist
`in wireless PHYs, because of the fast fading characteristic.
`In an average, the distance could be roughly mapped to
`the SNR. With this assumption, the modulation scheme or
`transmission rat~ could be based on distance. The radius
`of our simulation model is set to be 75 meter for both the
`infrastructure .network and ad hoc network. Acceptable
`transmission disllmces for three data rates are set to be 75, ·
`45, and 30 meter respectively.
`A two-states burst-error channel model is used, the
`good state represents a lower BER, I o-R and the bad state
`represents a fadin'g condition with a higher BER, 10·5
`•
`These
`two states are assumed
`to be exponentially
`·distributed with parameters 30ms and 10 ms, respectively.
`Attributes of multirate and singe-rate WLANs using
`the HRIDSSS/~hort system and the original IEEE 802.11
`WLAN are shown in Table 2.
`
`4.2. Simulatioij results and comparison
`
`The goodpt,H is defined as the successfully received
`MSDU per second. The delay is defined as the average
`time in ms fr()m an MSDU arrival to complete sending.
`The arrival rate is normalized by 2 Mbps.
`In an infra&tructure network, the throughout stays for
`different numb!lr of users [ 19). To compare between a
`single-rate and a multirate WLAN, a fixed number of 20
`users
`is selected.
`In Fig. 6,
`the multirate of the
`HRIDSSS/short (MR_Short),
`the single rate of the
`HR!DSS/short (SR_Short) system and the original IEEE
`802.11 WLAN · (SR_Long) in an infrastructure network
`are representeq by curves. The traffic load from an AP is
`assume to be 60%, p = 0.6. The highest available
`transmission rates are respectively 2.4, 1.5, and 1.3 Mbps,
`infrastructure network. Both
`the
`in an
`respectively,
`transmission nttfl and goodput are significantly improved
`in a multirate WLAN and the HRIDSSS/short system is
`better than the original IEEE 802.11 WLAN. The delay
`
`415
`
`Table I . Values of attributes in the IEEE 802.11
`
`WLAN
`Attribute
`MAC header
`RTS frame
`CTS frame
`ACK frame
`SIFS
`DIFS
`Slot time
`Short retry count
`Long retry count
`Average MSDU length
`aFragThreshold
`Collision detection delay
`Migration Probability
`
`Tvpical Value
`34 octets
`20 octets
`14 octets
`14 octets
`J0 J.IS
`50 J.IS
`20 J.IS
`4
`7
`1000 octets
`800 octets
`5 J.IS
`0.5
`
`Table 2. Attributes of multirate and single-rate
`
`WLANs
`
`Attribute
`
`HRIDSSS/Short
`
`Multirate
`
`Single
`rate
`
`IEEE
`802.11
`WLAN
`
`2, 5.5, 11
`
`2
`
`2
`
`Data rates
`(Mbps)
`PLCP
`preamble
`PLCP header
`48 bits
`48 bits
`48 bits
`aRTSThreshold Ooctet 250 octets 250 octets
`aCWmin
`31
`7
`7
`aCWma.x
`127
`127
`1023
`
`72 bits
`
`72 bits
`
`144 bits
`
`increases sharply when the system is near saturation.
`In Fig. 7, a single-rate WLAN and a multirate WLAN
`in an ad hoc network are compared at a fixed number of
`20 mobile stations. The highest available transmission rate
`are about 1.9, 1.5, and 1.4Mbps, respectively, in an ad hoc
`network. The
`transmission
`rate and
`thn;mghput are
`improved when the proposed multirate scheme is used.
`The delay increases sharply when the arrival rate reaches
`0.75, 0.6 and 0.55 respectively.
`In an infrastructure network, the traffic load from an
`AP significantly affects the performance in the multirate
`scheme. Different traffic loads are shown in Fig. 8 where
`Infra_80, Infra_60, and Infra_ 40 represent, respectively,
`the 80%, 60%, and 40% traffic load from an AP. Ad hoc
`represents the multirate WLAN in an ad hoc network.
`
`

`
`The petfonnance of an infrastructure network is
`better than an ad hoc network. In an average, the distance
`between an AP and a station is shorter than that between
`two stations. The selected data rate between an AP and a
`station is higher. However, the delay time in an AP is
`almost the same as the delay time in an infrastructure
`network. The bottleneck in an infrastructure network
`comes from the AP, when the traffic load is close to the
`system capacity.
`Simulation results showed that the proposed multirate
`scheme
`improves
`the
`petformance
`both
`in
`an
`infrastructure network and an ad hoc network. The
`
`3 ~------------------,
`
`limitation problem of single high-rate Wlnsmission is
`overcome by the multirate WLAN.
`The major effect is the MHT problem. in this paper we
`design a two steps NAV reservation scheme to alleviate it.
`In summary, the proposed multirate scheme is better both
`in an infrastructure network and an ad hoe network.
`
`5. Conclusion
`
`In the IEEE 802.llb standard, 5.5 and IIMbps data
`rates have been proposed, while 2Mbps and lMbps are
`currently in use. The high-rate transmission is limited to a
`
`200 r-----+--+------,r--'-=----,
`
`l 2.5
`
`1.5
`
`-1- MRJhortr-------;~f=Gi=iiii:i
`+ SRJh
`
`~
`
`5
`>-<U
`1i
`Q
`
`!50
`
`100
`
`50
`
`-tzMR_short
`-¥SRJh
`*SR Lono
`
`~·· - ~
`
`-
`
`b
`
`0 0.15 0.3 0.45 0.6 0.75 0.9 1.05 1.2 1.35 1.5
`Normalized arrival rate
`
`o~~~~LJ~~~
`
`0 0.15 0.3 0.45 0.6 0.75 0.9 1.05 1.2 1.35 .1.5
`Normalized arrival rate
`
`Figure 6. Multirate and single-rate schemes in an infrastructure network
`
`2.5 r - - - - - - - - - - - ,
`
`-1- MRJhortr----~~:u:J
`+SR_sh
`
`0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 I l.l 1.2
`Normalized arrival rate
`
`!50
`! 100
`~
`43
`Q 50~-------~·F--~~=---~
`
`0 ~~~~..L_L='=-..L_j_j
`
`0 0.1 0.2 0.3 0.4 0.) 0.6 0.7 0.8 0.9 I 1.1 1.2
`Normalized arrival r'ai~
`
`Figure 7 . Multirate and single-rate schemes in an ad hoc network
`
`416
`
`

`
`_., Infra_80
`~ Infra_60
`-*"'Infra_ 40
`-+-Adhoc
`
`2.7
`'R 2.5
`~ 2.3
`~ 2.1
`5
`·u; 19
`·~ '
`~1.7
`1.5
`
`200
`
`150
`........
`"' e.
`i> IOO
`....
`
`C)
`
`50
`
`-+-Infra_80
`-+- Infra_60
`-IE- Infra_ 40
`-+ Adhoc
`
`0 0.15
`
`0.75 0.9 !.OS
`0.6
`0.45
`0.3
`Normalized arrival rate
`
`1.2
`
`0
`
`0.15
`
`0.9
`0.75
`0.6
`0.45
`0.3
`Normalized arrival rate
`
`1.05
`
`1.2
`
`Figure 8. Comparisons between infrastructure and Ad Hoc networks
`
`the multirate
`range. Therefore,
`shorter propag11tion
`mechanism is proposed to enhance the capacity of the
`current IEEE so;u I WLAN. The multirate scheme is not
`rates
`transmitting at
`the
`to provide d\ff(lrent data
`predetermined ~ata rate, but is selected dynamically
`according to tht;l transmission quality.
`In our proppsed multirate WLAN under the DCF,
`stations and tb!! AP could select the transmission rate
`dynamically
`!\PIJOrding
`to
`the detected SNR. The
`RTS/CTS me!li);lnism
`is used
`to prevent HTs from
`interfering data iransfer. MHT problems under the DCF
`also could be solved by the proposed MAC control
`scheme. Becau~(l the access method is not changed under
`the DCF, it is mU!lh efficient to access the shared medium.
`The predetennined single-rate WLAN, either II Mbps
`or 5.5 Mbps dl!!a rate is chosen, the data throughput would
`be better than th\l proposed. However, the coverage range
`is limited in a shorter range. Simulation results show that
`the
`transmission
`rate and goodput are significantly
`improved cornpared to single-rate WLANs. The access
`delay is also iniprpved.
`
`References
`
`[I] Wireless LAN Medium Access Control (MAC) and
`Physical Ljiy~ r (PHY) Specifications, IEEE Stds. 802.JI ,
`Jan. 1997.
`·
`[2] Wireless LAN Medium Access Control (MAC) and
`Physical L!ly~r (PHY) Specifications, IEEE Stds. 802. Il ,
`1999, First ~ition .
`[3] R. Van N~.ll . G. Awater, M. Morikura, H. Takanashi, M.
`Webster, and K.W. Halford, "New High-Rate Wireless
`LAN Standards," IEEE Commun. Mag ., Vol.37, No.l2,
`Dec. 1999, pp,B2-88.
`[4] Wireless LAN Medium Access Control (MAC) and
`
`417
`
`Inc.,
`
`Physical Layer (PHY) Specifications: Higher Speed
`Physical Layer (PHY) Extension in the 2.4GHz band,
`IEEE Std 802.1/b/D5.0, April 1999.
`[5] Wireless LAN Medium Access Control (MAC) and
`Physical Layer (PHY) Specillcations: Higher Speed
`Physical Layer (PHY) Extension in the 5GHz band, IEEE
`Std 802.Jia/D5.0, Aprill999.
`[6] N. Morinaga, M. Nakagawa, and R. Kohno, "New
`Concepts and Technologies for Achieving Highly Reli able
`and High-Capacity Multimedia Wireless Communications
`Systems," IEEE Commun. Mag. , Jan. 1997, pp. 34-40.
`[7] Aironet
`Wireless
`Communication
`http://www.aironet.com/.
`[8] B.P. Crow, I. Widjaja, J.G Kim, P.T. Sakai, "IEEE 802.11
`Wireless Local Area Networks," IEEE Commun. Mag.,
`Sepl. 1997, pp.ll6-126.
`[9] R.O. Lamaire, A. Krishna, P. Bhagwat, and J. Panian,
`"Wireless LANs and Mobile Networking : Standards and
`Future Directions," IEEE Commun. Mag., Aug. 1996,
`pp.86-94.
`[10] Kwand-Cheng Chen, "Medium Access Control of Wireless
`LANs for Mobile Computing," IEEE Network, Sept./Oct.
`1994, pp.S0-63.
`(II] K. Halford, S. Halford, M. Webster, and C. Andren,
`"Complementary Code Keying for Rake-Based Indoor
`Wireless Communication," Proc. of IEEE ISCAS99, Vol.4,
`July 1999, pp.427-430.
`(12] "Complememtary Code Keying Made
`http://www. intersil.com/, AN9850, Oct. 1999.
`[ 13] H.S. Chhaya, S. Gupta, ''Performance of asynchronous
`data transfer methods of IEEE 802.11 MAC protocol,"
`IEEE Personal Commun., Vol.3, No.5, Oct. 1996, pp.B-15.
`[14] S. Khurana, A. Kahol, S.K.S. Gupta, P.K. Srimani,
`"Performance evaluation of distributed co-ordination
`function for IEEE 802.11 wireless Jan protocol in presence
`of mobile and hidden tenninals," Proc. of Modeling,
`Sim11lation
`of Comp111er
`and
`Analysis
`and
`
`Simple,''
`
`

`
`Telecommunication Systems, 1999, pp.40-47.
`[IS] V. Bharghavan, "Perfonnance evaluation of algorithms for
`wireless medium access," Proc. of IEEE International
`Computer Performance and Dependability Symposium,
`1998, pp.86-95.
`[16] K. C. Zangi and R. D. Koilpillai, "Software Radio Issues in
`Cellular Base Stations," IEEE JSAC, vol. 17, no. 4, April
`1999, pp. 561-573
`[17] N. Morinaga, M. Nakagawa, and R. Kohno, "New
`Concepts and Technologies for Achieving Highly Reliable
`and High-Capacity Multimedia Wireless Communications
`Systems," IEEE Commun. Mag., Jan. 1997, pp. 34-40.
`[18) H. H. Liu and J. L. C. Wu. "Packet Telephony Suppon for
`IEEE 802.11 Wireless LAN," Proc. of 13'11
`IEEE
`International Conference on Information Networking,
`Cheju Island, Korea, Vol. I, Jan. 1999, pp.4A.4.1· 4A.4.6.
`[ 19] Yi-Jen Lung, "Perfonnance Evaluation of Multi rate
`Supponed IEEE 802.11 Wireless LAN," Master Thesis,
`Computer Science and Information Engineering, NTUST,
`July 2000.
`
`418
`
`

`
`EXHIBIT B
`EXHIBIT B
`
`

`
`Physical Item Editor
`
`3/6/15, 9:54AM
`
`Tasks
`
`Analytics Currently at: Music Library -
`
`Physical Item Edi,()r
`
`Default Cir ...
`
`15th International Conference on Information Networklng_;_P-roceeding.§.,_ll
`Resource
`description JaniJarY.-2 Februa[Y.,.2QQ1,~P-P-LI CitY. . ...Qiill,.,@pan /International Conference
`on Information Networking Beppu-shi,_,@P-9.fi).2QQ.1_;_(15th : IEEE Comf2!J!m:
`SocietY. Los Alamitos, Calif. : c2001 . [0769509533 (microfiche)]
`
`H~
`
`Ammerman , Jack
`
`Holding Science & Engineering LibrarY.: Stacks;
`TK5105.5 .15715 2001
`Barcode 11719022950465
`Process
`-
`
`I
`
`Barcode 11719022950465
`Created by import
`
`Status Item in place
`
`Updated by-
`
`Current Location Science & Engineering Library:
`Stacks; TK5105.5 .15715 2001
`
`L<lr.tltlon lnfe>rmntlon
`
`Item in temporary
`locati~,>n
`
`Temporary Item policy-
`
`~llrlnls JnformnlliiJ)
`
`Description -
`
`© Ex Libris Ltd., 2015
`
`https ://alma. ex II brls group .co m/m n g/actl on/home .do? mode=a]ax# b
`
`Page 1 of 1
`
`View all holding~
`
`View all items
`
`if Notes
`
`l[ History
`
`Gener!lllnformatlon
`
`; 1
`
`ENUM/CHRON Information
`
`1
`
`1\
`
`typej·,;
`Summary
`I ltflJD JnfPrmnlltm
`Item ID 23M4581120001161
`Created on 2001-03-12
`19:00:00
`Updated on-