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`02--
`
`COVER SHEET FOR PROVISIONAL APPLICATION FOR PATENT
`
`~"O
`'"i
`~tant Commissioner for Patents
`Box PROVISIONAL PATENT APPLICATION
`Washington, DC 20231
`
`Sir:
`
`This is a request for filing a PROVISIONAL APPLICATION under 37 CFR 1.53(c).
`
`Docket Number
`
`0 I 0629-0043-888
`
`INVENTOR(s) APPLICANT(s)
`
`I Type a plus sign{+)
`
`inside this box ~
`
`I
`
`+
`
`LAST NAME
`
`FIRST NAME
`
`MIDDLE INITIAL
`
`RESIDENCE (CITY AND EITHER STATE OR FOREIGN COUNTRY)
`
`CHANNEL, CODING AND POWER MANAGEMENT FOR WIRELESS LOCAL AREA NETWORKS
`
`TITLE OF THE INVENTION (280 characters max)
`
`CORRESPONDENCE ADDRESS:
`
`PENNIE & EDMONDS LLP
`1 •• 1.111 •••• 1.1.1 •• 1 ... 11 ••• 1.11
`ENCLOSED APPLICATION PARTS (check all that apply)
`
`20583
`
`181 Specification
`
`Number of Pages
`
`181 Drawing(s)s
`
`Number of Sheets
`
`84
`
`28
`
`lill Applicant claims small entity status, sec 37 CFR §1.27
`
`D Other (specify)
`
`METHOD OF PAYMENT (check one)
`
`0 A check or money order is enclosed to cover the Provisional filing fees.
`
`ESTIMATED
`PROVISIONAL
`FILING FEE
`AMOUNT
`
`$160
`
`l8I The Commissioner is hereby authorized to charge the required filing fee to Deposit Account Number 16-I I 50.
`
`The invention was made by an agency of the United States Government or under a contract with an agency of the United States Government.
`181 No.
`D Yes, the name of the U.S. Government agency and the Government contract number are: - - - - - - - - - - - - - - - - - - - - -
`
`Respectfully submitted,
`
`REGISTRATION NO. 136,196
`(if appropriate)
`
`L. - - - - - - - - - - '
`
`Date I February 13, 2003
`Total number of cover sheet pages. D
`
`0 Additional inventors are being named on separately numbered sheets attached hereto.
`
`PROVISIONAL APPLICATION FILING ONLY
`
`NY2 - 139978.J. !
`
`Hewlett Packard Exhibit 1008, Page 1 of 113
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`IPR2021-01377
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`fl"'(•
`11,,JI
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`CHANNEL, CODING AND POWER MANAGEMENT FOR WIRELESS LOCAL
`AREA NETWORKS
`
`FIELD OF THE INVENTION
`
`This application relates to the field of Wireless Local Area Network (WLAN)
`network management.
`
`5
`
`BACKGROUND
`
`In a WLAN, one or more base stations or Access Points (AP) bridge between a
`wired network and radio frequency or infrared connections to one or more
`mobile stations or Mobile Units (MU). The MUs can be any of a wide variety of
`devices including, laptop computers, personal digital assistants, wireless bar
`code scanners, wireless point of sale systems or payment terminals, and many
`other specialized devices. Most WLAN systems used in business and public
`access environments adhere to the IEEE 802.11 specifications. Other WLANS
`the specifications
`including,
`technologies
`are based on other wireless
`Interest Group, proprietary radio
`the Bluetooth Special
`promulgated by
`frequency protocols and infrared link protocols.
`
`Wireless Local Area Networks (WLANs) are now in common use in both large
`in home
`Internet access points, and
`and small businesses, as public
`environments. Millions of base-stations or access points and mobile units are
`now deployed. This increasing density of access points creates additional
`network management problems. Specifically access points using the same or
`overlapping frequency bands or channels and the same or similar signal coding
`have the potential to create mutual interference. Mutual interference leads to
`packet collisions, the need to retransmit packets, potentially reducing network
`throughput. At the same time, the coverage area of the access points may not
`
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`be sufficient, leading to poor signal quality at the edges of the network or
`"coverage holes".
`
`5
`
`Conventional approaches to the optimization of wireless networks involve
`making surveys of the desired coverage area. The results of these surveys are
`then used to determine the optimum settings for channel selection, signal
`coding and power for the access points. Attempts may also be made to
`determine if existing access points should be moved to other locations or new
`access points added to the wireless network. Survey approaches suffer from
`several difficulties including:
`
`10
`
`1.
`
`It is usually quite expensive to collect and analyze the data.
`
`2. The survey data is static. Thus, if conditions change within the area of
`interest the survey would need to be run once again or the design of the
`wireless network would be less than optimal.
`
`3. The equipment used to make the survey typically has fixed and
`distinctive physical properties (antennas, receivers, velocity of travel,
`etc.). In practice, mobile units will have different physical properties and
`will therefore experience the wireless network quality that is different
`from the survey equipment.
`
`involve the
`Other approaches to management of wireless networks can
`collection of signal measurements by access points. In these schemes, the
`wireless network management system uses signal information collected by the
`access points as a basis to adjust the channel assignments, signal coding
`assignments and power levels, in attempts to optimize network performance. In
`most cases the access points collect information on the signals broadcast by
`the other access points. These schemes suffer from a number of drawbacks
`including:
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`1. The access points can only take measurements at fixed locations;
`
`12. The receiver and antenna properties of the access point can be quite
`different from those of the mobile units;
`
`3. The transmission power levels of the access points and mobile units
`may be quite different; and,
`
`5
`
`4. The possible use of diversity antennas in access points, but not in
`mobile units.
`
`5. Each single access point only has local knowledge of the environment
`and are thus, unlikely to make changes that are globally optimal.
`
`10
`
`SUMMARY
`
`The channel, coding and power management system described overcomes the
`deficiencies of prior art power, coding and channel management systems
`through a simplified approach using data collected from mobile units to
`optimize the performance of the network. The system provides for the
`15 management of WLANs in cases where unmanaged access points are present.
`Further, the system can provide information on the possible need to add
`access points.
`
`The channel, coding and power management system uses signal data and
`network traffic statistics collected by the mobile units to determine optimal
`configuration settings for the access points. The access point settings
`managed by the system can include the operating channel or center frequency,
`orthogonal signal coding used, if any, and the transmission power. In som~
`embodiments, signal coding can include the data rate used by the mobile units
`and the access points, which may also be controlled. The solutions computed
`can account for the inherent trade-offs between wireless network coverage
`3
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`area and mutual interference. Mutual interference arises when two or more
`
`access points use the same or overlapping frequency bands or channels and
`
`the same of similar signal coding. These situations can arise as a result of the
`
`often-limited choice available of channels and orthogonal codes. Higher levels
`
`5
`
`of mutual interference can lead to low network data throughput. On the other
`
`hand, reasonable access point transmission power must be maintained to
`
`achieve coverage of the desired areas.
`
`Any device can perform the collection and reporting of radio frequency signal
`
`data if it has the required receiver, signal measurement capabilities and any
`
`10
`
`type of data connection to data repository. In the following discussion, these
`
`devices will be referred to has "mobile units", but can in fact include a number
`
`of other types of devices including:
`
`1. The device may be any type of general-purpose computer, for which the
`
`main purpose is not to collect data, but rather collects data and reports in
`available idle time.
`
`15
`
`2. The device used for data collection may not require any special purpose
`
`hardware or driver software, but may only use standard configurations.
`
`3. The device may or may not move with time.
`
`4. The device may be dedicated to the collection of radio signal data at a fixed
`
`20
`
`location or moving between several locations with time.
`
`5. May have one or more additional network interfaces, some of which may
`connect to wired networks or other wireless networks.
`
`The computations of the channel, coding, and power management system can
`
`determine neighbor relationships between access points without the need for
`
`25
`
`geographic location data. In some embodiments, the system uses signal
`4
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`5
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`10
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`15
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`25
`
`the relative
`to determine
`relationships between access points
`strength
`distances. These distances are then used to determine neighbor relationships
`between the access points. These neighbor relationships are, thus, based on
`radio frequency propagation or path loss relations, and may more accurately
`define the coverage areas of the access points and the potential for mutual
`interference when compared to the geometric of geographically defined models
`In some alternative embodiments, geographic location of the access points can
`In yet other alternative
`to determine neighbor relationships.
`be used
`embodiments, geographic location of the access points, along with signal
`strength measurements from the mobile units, can be used to determine
`neighbor relationships.
`
`In some embodiments, the mobile units will experience signal interference from
`unmanaged access points or other sources of in-band radio frequency energy.
`The access point settings determined by the system can account for these
`sources. Typically, signal strength information and neighbor relationships are
`used in these computations.
`
`The same data collected by the mobile units can be used to report on and
`possibly respond to the state of network performance. System administrators
`use the system's reporting capabilities to determine if the network is operating
`properly, to review automatically computed access point setting changes, and if
`required perform manual settings. Thus, the system can accommodate a
`mixture of automatic and manual control and reporting techniques.
`
`Signal data and traffic statistics collected by the mobile units can be subject to
`considerable variation or fluctuations. These variations or fluctuations arise
`from a number of sources, including multi-path signal propagation, variations in
`the network
`in
`time dependant changes
`mobile unit characteristics,
`environment, and different travel paths used by the different mobile units. The
`limited dynamic range and noise characteristics of the mobile unit receivers
`
`5
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`can also contribute to fluctuations or variations in signal measurements.
`the use of different access point
`for
`Additional variation can arise
`characteristics and transmission power levels. In some embodiments, the data
`collected by the mobile units is preprocessed by a number of techniques,
`including censoring, combining, and power correction.
`
`In some embodiments, the rate at which access point settings are updated can
`be adjusted. These time-dependent parameters allow the system to compute
`stable solutions, based on the long-term behavior of the network. If these time
`to
`response
`in
`the settings may change
`too short,
`constants are
`inconsequential changes in network measurements (i.e. variations in traffic
`volume), which can lead to unstable behavior or oscillations. If these time
`constants are too long, the access point settings may not change rapidly
`enough to respond effectively to changes in the network environment. Some
`embodiments incorporate parameters controlling the rate of changes in access
`point settings when a known change has been made to the network. Examples
`of known changes to the network include, the failure of an access point, the
`the removal of a managed access
`addition of a managed access point, and
`point.
`
`In some embodiments, the channel, code and power management system can
`control the operation of redundant access points. If redundant-access points
`increased mutual
`the result can be
`in an online state,
`are maintained
`interference and reduced network throughput as a result of having multiple
`access points with redundant coverage areas using a limited set of channels
`and orthogonal signal codes. To overcome these difficulties, but still allow for
`redundancy and high-availability, some embodiments of the power, channel
`and code management system includes the capabilities to manage redundant
`access points in an offline configuration and only bring them online when
`required.
`
`5
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`.,, [/I
`
`.::II ..
`
`llJ:::
`
`Depending on the details of the embodiment, the channel, code and power
`
`management system can apply to a variety of (often approximate) solution
`algorithms to the computation of optimal access point settings. A given solution
`
`5
`
`technique can attempt to find the local (with respect to neighbors) solution for
`an access point's channel, signal coding and power settings. In other cases the
`solution can determine a globally optimum solution. In some embodiments an
`
`iterative or stepwise solution considering the local neighborhood for a given
`
`access point is applied.
`
`In other embodiments these solution
`
`iterative
`
`techniques are used to compute globally optimized solutions. Some other
`1 o alternative embodiments can apply linear or nonlinear optimization techniques
`to the computation of a solution.
`In yet other alternative embodiments,
`evolutionary solution techniques can be used to compute local, or global
`
`solutions.
`
`It will be appreciated that the foregoing statements of the features of the
`
`15
`
`invention are not intended as exhaustive or limiting, the proper scope thereof
`being appreciated by reference to this entire disclosure and to the substance of
`the claims.
`
`It will be understood that while the discussions contained in this document refer
`
`specifically to local area wireless networks with fixed base stations, it will be
`
`20
`
`understood that the ideas discussed are equally applicable to wide area
`
`wireless networks and peer-to-peer wireless networks without fixed access
`points or base stations.
`
`BRIEF DESCRIPTION OF FIGURES
`
`The invention will be described by reference to the preferred and alternative
`embodiments thereof in conjunction with the drawings in which:
`
`25
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`Hewlett Packard Exhibit 1008, Page 8 of 113
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`IPR2021-01377
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`Fig 1 is a simplified diagram showing signal strength measurements by mobile
`units;
`
`Fig 2 is a hypothetical bit error rate curve for a mobile unit receiver;
`
`Fig 3 is an example of network throughput versus submitted data;
`
`5
`
`Fig 4 is a simplified overall system block diagram;
`
`Fig 5A, 58, and 5C is a simplified diagram of a technique to determine
`propagation distance between access points;
`
`Fig 6A, 68, and 6C is a diagram showing a simplified example of access point
`configuration;
`
`10
`
`Fig 7A, 78, 7C, 70, 7E, 7F, 7G, and 7H is a simplified process flow diagram;
`
`I,
`
`Fig 8 is an example of access point coverage with mutual interference;
`
`Fig 9 is an example of access point coverage with reduced mutual interference;
`
`Fig 10 is an example of access point coverage with mutual interference;
`
`is an example of access point coverage with
`Fig 11
`interference;
`
`15
`
`reduced mutual
`
`Fig 12 is an example of access point coverage with a hole;
`
`Fig 13 is an example of expanded access point coverage;
`
`Fig 14 is an example of access point coverage with a new access point;
`
`Fig 15 is an example of access point coverage with an offline access point;
`8
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`Fig 16 is an example of access point coverage with increased power;
`
`Fig 17 is an example of access point coverage with overlap; and,
`
`Fig 18 illustrates an example of an access point configuration with redundancy.
`
`DETAILED DESCRIPTION OF EMBODIMENTS
`
`5
`
`10
`
`The following detailed description refers to the accompanying drawings, and
`invention. Other
`the present
`describes exemplary embodiments of
`embodiments are possible and modifications may be made to the exemplary
`embodiments without departing from the spirit, functionality and scope of the
`invention. Therefore, the following detailed descriptions are not meant to limit
`the invention.
`
`Overview of the Embodiments
`
`15
`
`To maximize performance and throughput of wireless networks, the mutual
`interference from the base-stations or access points experienced by the mobile
`units must be minimized. Mutual interference arises when two or more access
`points use the same or overlapping frequency bands or channels and the same
`or similar signal coding. While it is desirable to reduce mutual interference, at
`the same time, the coverage area of the wireless network must be maintained.
`Thus, the selection of channels, the selection of signal coding and the setting
`of power levels for the access points must balance the competing desires to
`20 maximize coverage area while minimizing mutual interference.
`
`The maximization of coverage area and minimization of mutual interference is
`real-world propagation
`the complex
`made more complicated by both
`environment and the fact that different mobile units have differing receiver and
`antenna characteristics. Thus, a wireless network optimized for one type of
`25 mobile unit applied to a particular range of applications may not be optimal for
`9
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`Hewlett Packard Exhibit 1008, Page 10 of 113
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`another type of mobile unit applied to another range of applications. A wide
`
`range of factors can affect how a given mobile unit experiences the quality of a
`
`wireless network including:
`
`"'[l!
`
`JL
`
`JJ],
`
`1. The type of antenna or antennas used;
`
`5
`
`2. Velocity of travel and hence signal fading environment;
`
`3. The possible use of antenna diversity techniques;
`
`4. Polarization of antennas;
`
`5. The types of modulation and signal coding; and,
`
`6. The presence or absence of wave scattering and obstructing objects
`
`Io
`
`giving rise to signal shadowing and multi-path propagation.
`
`Another complicating factor is the presence of unmanaged access points or
`other sources of radio frequency energy. An unmanaged access point can be
`
`any access point in or near the coverage area of interest. These unmanaged
`
`access points and sources of radio frequency energy can include:
`
`15
`
`1. Access points that belong to the organization managing the wireless
`
`network, but lacking the properties required to control any one or all of
`power, channel selection, and coding;
`
`2. Access points under the control of other organizations but in the general
`
`area of the wireless network being managed;
`
`20
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`3. Other radio services sharing the same spectrum, including remote
`control devices, cordless telephones, and data devices using other
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`communications protocols and standards (e.g., Bluetooth vs.
`802.11 standards); and,
`
`IEEE
`
`4. Other sources of broadband interference including, electric motors and
`other electrical equipment, and electronic devices.
`
`5 The complex environment affecting the quality of the wireless network is further
`complicated by the fact that the environment and even the properties of the
`mobile units themselves can dynamically change in time. It is not unusual for
`the physical environment to change. For example, construction can add or
`remove obstacles or objects scattering and shadowing signals. Managed
`access points may be moved over time for any number of reasons. The
`presence, absence, location or characteristics of unmanaged access points or
`other sources of radio frequency energy can change over time, sometimes at a
`rapid rate. Finally, new types of mobile units are introduced, which may have
`different physical properties or may be applied in new applications and will
`therefore experience the wireless network environment differently.
`
`15
`
`10
`
`20
`
`Figure 1 shows a simplified diagram of signal strength (RSSI) measurements
`experienced by mobile units. The access points 14 broadcast signals to the
`mobile units 16. The mobile units receive signals from one more access points.
`In this example the strength of the RSSI measured by the mobile unit from
`each access point is shown by a number in the box next to the dotted line
`connecting the mobile unit to that access point. In the example shown in Figure
`1, mobile unit MU2 receives relatively strong signals from access points AP1
`and AP2, and receives a weaker signal from AP3. Depending on the channels
`and signal coding used by the mobile unit MU2 may experience more or less
`25 mutual interference between these access points. Likewise mobile unit MU1
`and MU3 receive signals a different strengths from the three access points.
`
`11
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`5
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`25
`
`Figure 2 shows an example of the Bit Error Rate (BER) performance of a
`wireless receiver versus the Signal to Noise Ratio (SNR). The performance
`curve 30 shows the expected BER of the receiver over a range of SNR. If the
`SNR is too low 32, the BER of the receiver may become too high for the
`application. Therefore, it is usually advantageous to design the wireless
`network so that the SNR is sufficient to achieve adequate BER performance in
`the areas where the mobile units 16 operate. It will be understood that the
`desired range of BER and the SNR required to achieve this range is dependent
`on a number of factors including, the physical properties of the mobile unit, the
`the
`techniques applied,
`type of signal modulation used, signal coding
`transmission bit rate used and the applications communicating over the
`wireless link. Certain signal coding techniques allow a mobile unit to effectively
`operate in the presence of interfering signals. These techniques involve the
`use of multiple orthogonal codes. In effect, these coding techniques provide
`another dimension within which signals can be separated by a receiver. A
`wide variety of well known and emerging orthogonal coding techniques are
`individually or in combinations,
`applied in wireless local area networks,
`including:
`
`1. Direct Sequence Spread Spectrum (DSSS) coding, which adds a high
`from a several possible orthogonal
`rate chip stream, chosen
`pseudorandom codes, to the bit stream, thereby adding resistance to
`errors during the decoding process; and,
`
`techniques, where
`(FHSS)
`2. Frequency Hopping Spread Spectrum
`transmission frequencies are selected from several possible orthogonal
`pseudo random sequences to minimize the impact of interference at
`particular frequencies.
`
`An additional signal coding variable can be the bit rate of transmissions used
`between the access points 14 and the mobile units 16. Transmissions at lower
`
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`bit rates will achieve lower bit error rates for a given signal to noise ratio, when
`compared to higher bit rates (and assuming the signal coding and other
`variables are identical in both cases). In other words, a lower bit rate results in
`a higher energy per bit (or symbol). In-effect, as the bit rate is decreased the bit
`error rate curve 30 in Figure 2 is shifted downward (to lower bit error rate at a
`given signal to noise ratio). As the bit rate is increased the bit error curve is
`shifted upward (higher bit error rate at a given signal to noise ratio).
`
`5
`
`The signal to noise ratio experienced by mobile units 16 depends on a wide
`variety of environmental factors including:
`
`10
`
`1. The signal level received at the mobile unit 16 from the access point 14;
`
`from other access point 14 signals, using
`interference
`2. Mutual
`overlapping frequency bands and similar signal coding, received by the
`mobile units 16;
`
`3. The multi-path signal environment experienced by the mobile unit 16;
`
`15
`
`4. Thermal or other electronic noise generated by the receiver of the
`mobile unit 16; and,
`
`5. Other sources of electronic noise in the environment, including other
`wireless services using the same frequency bands and electronic or
`electrical equipment in the area.
`
`20
`
`25
`
`As an example, if the mobile unit 16 MU 1, shown in Figure 1, receives two
`packets transmitted, in overlapping time periods on the same channel, bit rate,
`and using the same signal coding, from access points 14 AP 1 and AP 2, the
`(-50 dBm)). Referring to the
`signal to noise ratio will be only 5 dB (-45dbm -
`example of Figure 2, a signal to noise ratio of only 5 dB is likely to result in a bit
`, making accurate reception of either packet
`error rate of approximately 10-1
`13
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`unlikely. On the other hand, if MU 1 receives two packets transmitted, in
`
`overlapping time periods on the same channel, bit rate, and using the same
`
`coding, from access points AP 1 and AP 3, the signal to noise ratio will be 25
`
`dB (-50dbm -
`
`(-75 dBm)). This signal to noise ratio should be more than
`
`5
`
`sufficient to accurately receive the packet transmitted by AP 1, according to the
`
`bit error rate curve 30 shown
`
`in Figure 2. Similar calculations and
`
`considerations can be applied to the other mobile units shown (MU 2 and MU
`
`3).
`
`Overview of Wireless Network Performance
`
`l O Performance optimization for a wireless network involves a tradeoff between
`
`geographic coverage and throughput. Adding more access points to a network
`
`can improve coverage, but can lead to greater mutual interference and
`
`therefore less data throughput. The greater the level of mutual interference, the
`
`greater the chance of a packet not being received correctly, and therefore
`
`15
`
`requiring retransmission. The increased retransmission or retry rate leads to
`
`lower total network data throughput. Further, complicating this coverage and
`
`mutual interference trade-off is the possible presence of nearby access points
`
`that are foreign
`
`to
`
`the network and are
`
`therefore not under network
`
`management control, or other sources of radio frequency interference.
`
`20
`
`The trade-offs between coverage and mutual interference can be formulated
`
`mathematically in a number or ways. The following analysis assumes that
`
`access points have
`
`fixed physical configurations
`
`(location, antenna
`
`configuration, electronic configuration, etc.). A coverage area of interest is
`
`defined over which to perform the analysis. Coverage areas can include a
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`25
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`room in a building, a portion of a building, a floor of a building, an entire
`
`building, a campus of buildings, or a larger region. Access point parameters
`
`under management of network administrators typically include the transmission
`
`power, the choice of transmission center channel (or transmission frequency
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`14
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`Hewlett Packard Exhibit 1008, Page 15 of 113
`Hewlett Packard Enterprise Company v. Intellectual Ventures II LLC
`IPR2021-01377
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`band), and the orthogonal signal coding applied to transmitted signals. In
`addition, the transmission bit rate used by the mobile units and access points
`may be under the control of the system. In this discussion it is assumed that
`different orthogonal signal codes can be used to separate signals in a code
`space, just as the use of different channels separates signals in frequency
`space. In most practical situations the choices of channels and signal codes
`that can be employed are limited to a relatively few choices. The objective is to
`optimize network performance by adjusting these managed parameters. In
`some cases, the key elements of the trade-off, as experienced by a mobile
`unit, can be formulated as follows:
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`5
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`10
`
`(1) MAX { C(area, bit rate, power)+
`
`A.,
`
`l(area, throughput, channel, bit rate, code, power)+
`
`A.2 U(area, throughput, channel, bit rate, code, power) }
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`15
`
`Referring to Equation 1; the goal is to maximize (MAX) the performance
`characteristics of the network. The elements of this formulation can be
`explained as follows:
`
`1. The coverage of the network (C(area, bit rate, power)) is a function of
`the area of interest (area), the transmission bit rate used, and the
`transmission power of the access points (power). In simplified terms, the
`higher the transmission power of the access points, the greater the
`signal strength and therefore the coverage area of the network. Lower
`transmission bit rates between the access points 14 and mobile units 16
`can increase the effective coverage area, whereas using higher bit rates
`will decrease the effective coverage area. Choice of channel or signal
`coding has little effect on coverage area.
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`20
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`25
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`Hewlett Packard Exhibit 1008, Page 16 of 113
`Hewlett Packard Enterprise Company v. Intellectual Ventures II LLC
`IPR2021-01377
`
`

`

`the
`transmitted by
`the signals
`interference between
`2. The mutual
`managed access points (l(area, throughput, channel, code, power)) is a
`function of the area of interest (area), the access point throughput or
`traffic level, the channels used by the access points (channel), the signal
`coding used by the access points (code), and the transmission power of
`the
`the higher
`terms,
`In simplified
`(power).
`the access points
`transmission power of the access points the greater the likelihood of
`mutual interference between the transmitted signals transmitted from the
`access points. This effect is in opposition to the greater cover area
`achieved by use of higher transmission power. The use of different
`channels or orthogonal codes separates signals in frequency or code
`space and therefore reduces mutual interference, regardless of the
`transmission power applied. The access point throughput determines
`the rate of packet transmission, which determines the probability of
`packet collisions or mutual interference. The transmission bit rate can
`change the affect of the interfering signal. An interfering signal with the
`same bit rate as the desired signal is more likely to cause interference
`likely corresponding higher
`than one with a higher bit rate (and
`bandwidth).
`
`3. The mutual interference between the signals transmitted by managed
`access points and unmanaged access points (U(area, throughput,
`channel, code, bit rate, power)) is a function of the area of interest
`(area), the access point throughput or traffic level (throughput), the
`channels used by the access points (channel), the signal coding used by
`the access points (code), and the transmission power of the access
`points (power). It should be noted that the radio frequency propagation
`components of this function would be the same regardless if the access
`point is managed or unmanaged. In simplified terms, the higher the
`transmission power of the managed access points the greater the
`likelihood that signals transmitted from these managed access points
`16
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`5
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`1 O
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`15
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`20
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`25
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`30
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`Hewlett Packard Exhibit 1008, Page 17 of 113
`Hewlett Packard Enterprise Company v. Intellectual Ventures II LLC
`IPR2021-01377
`
`

`

`will be able overcome the mutual interference created by signals
`transmitted by the unmanaged