(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2007/0173260 A1
`(43) Pub. Date:
`Jul. 26, 2007
`Love et al.
`
`US 20070173260A1
`
`(54) WIRELESS COMMUNICATION NETWORK
`SCHEDULING
`
`(22) Filed:
`
`Jan. 23, 2006
`
`(76) Inventors: Robert T. Love, Barrington, IL (US);
`Brian K. Classon, Palatine, IL (US);
`Edgar P. Fernandes, Winchester (GB);
`Armin W. Klomsdorf, Libertyville, IL
`(US); Vij ay Nangia, Algonquin, IL
`(US); Ravikiran Nory, Grayslake (IL);
`Dale G. SchWent, Schaumburg, IL
`(US); Kenneth A. Stewart, Grayslake,
`IL (US); David R. Wilson, Hainesville,
`IL (US)
`
`Correspondence Address:
`MOTOROLA INC
`600 NORTH US HIGHWAY 45
`ROOM AS437
`LIBERTYVILLE, IL 60048-5343 (US)
`
`(21) Appl. No.:
`
`11/337,856
`
`Publication Classi?cation
`
`(51) Int. Cl.
`(2006.01)
`H04Q 7/20
`(52) U.S. c1. ......................... ..455/450; 455/509; 455/522
`
`(57)
`
`ABSTRACT
`
`A method in a Wireless communication network infrastruc
`ture scheduling entity, including allocating a radio resource
`to a schedulable Wireless communication entity in the Wire
`less communication network, the radio resource allocated
`based on a maximum poWer available to the schedulable
`Wireless communication entity for the radio resource allo
`cated, the radio resource allocated based on an interference
`impact of the schedulable Wireless communication entity
`operating on the radio resource allocated.
`
`10_0
`
`I
`
`PSTN
`
`130
`
`120
`
`CONTROLL
`ER
`
`PDN
`
`140
`
`Apple Inc. v. Cellular Communications Equipment LLC
`APPL-1013 / Page 1 of 13
`
`

`
`Patent Application Publication Jul. 26, 2007 Sheet 1 0f 6
`
`US 2007/0173260 A1
`
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`PSTN
`
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`
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`
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`
`APPL-1013 / Page 2 of 13
`
`

`
`Patent Application Publication Jul. 26, 2007 Sheet 2 0f 6
`
`US 2007/0173260 A1
`
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`
`APPL-1013 / Page 3 of 13
`
`

`
`Patent Application Publication Jul. 26, 2007 Sheet 3 0f 6
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`US 2007/0173260 A1
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`Patent Application Publication Jul. 26, 2007 Sheet 5 0f 6
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`Patent Application Publication Jul. 26, 2007 Sheet 6 of 6
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`APPL-1013 / Page 7 of 13
`
`APPL-1013 / Page 7 of 13
`
`
`

`
`US 2007/0173260 A1
`
`Jul. 26, 2007
`
`WIRELESS COMMUNICATION NETWORK
`SCHEDULING
`
`[0009] FIG. 4 illustrates occupied bandWidth poWer de
`rating values.
`
`FIELD OF THE DISCLOSURE
`
`[0001] The present disclosure relates generally to Wireless
`communications, and more particularly to radio resource
`scheduling in Wireless communication networks, corre
`sponding devices and methods.
`
`BACKGROUND
`[0002] Some effort is being expended during the speci?
`cation phase of contemporary broadband Wireless commu
`nication standards such as the 3GPP Long Term Evolution
`(LTE) project, also referred to as Evolved UMTS Terrestrial
`Radio Access or E-UTRA, to improve the performance and
`ef?ciency of the poWer ampli?er (PA) in mobile terminals or
`user equipment (UE). ToWard this objective, there are a
`number of key performance metrics, but the over-riding goal
`is to minimiZe the PA poWer consumption (or peak and/or
`mean current drain), cost and the complexity required to
`deliver a given speci?ed conducted poWer level, for
`example, +21 dBm or +24 dBm, to the UE antenna.
`[0003] Generally, the required conducted poWer level
`must be achieved Within a speci?ed loWer bound on in-band
`signal quality, or error vector magnitude (EVM) of the
`desired Waveform, and an upper bound of signal poWer
`leakage out of the desired signal bandWidth and into the
`receive signal band of adjacent or alternate carrier receivers.
`These effects may be subsumed into the broader term
`“Waveform quality”.
`[0004] These problems represent classical PA design chal
`lenges, but emerging broadband Wireless netWorks such as
`3GPP LTE must solve these problems in the context of neW
`modes of system operation. For example, poWer ampli?er
`(PA) operation must be optimiZed While transmitting neW
`Waveform types, including multi-tone Waveforms and fre
`quency-agile Waveforms occupying variable signal band
`Widths (Within a nominal bandWidth, sometimes referred to
`as a channel or carrier bandWidth). Further, PA performance
`must noW be optimiZed in a predominantly packet sWitched
`(PS) netWork Where a netWork entity, such as a base station,
`schedules multiple Wireless communication entities or ter
`minals to transmit simultaneously. PA performance also
`must be optimiZed in the presence of numerous different
`frequency or spatially adjacent radio technologies, including
`GSM, UMTS, WCDMA, unlicensed transmitter and receiv
`ers, among other radio technologies.
`[0005] The various aspects, features and advantages of the
`disclosure Will become more fully apparent to those having
`ordinary skill in the art upon careful consideration of the
`folloWing Detailed Description thereof With the accompa
`nying draWings described beloW. The draWings may have
`been simpli?ed for clarity and are not necessarily draWn to
`scale.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0006] FIG. 1 illustrates an exemplary Wireless commu
`nication system.
`
`[0007] FIG. 2 illustrates a Wireless communication entity.
`
`[0008] FIG. 3 illustrates neighboring communication net
`Works.
`
`[0010] FIG. 5 illustrates a radio resource assignment to
`multiple entities.
`
`[0011] FIG. 6 illustrates a poWer ampli?er under control of
`a controller modifying the maximum poWer level.
`
`[0012] FIG. 7 illustrates a received signal at a Wireless
`communications receiver, conditioned on the maximum
`poWer of a Wireless transmitter poWer ampli?er.
`
`DETAILED DESCRIPTION
`
`[0013] In FIG. 1, the exemplary Wireless communication
`system comprises a cellular netWork including multiple cell
`serving base stations 110 distributed over a geographical
`region. The cell serving base station (BS) or base station
`transceiver 110 is also commonly referred to as a Node B or
`cell site Wherein each cell site consists of one or more cells,
`Which may also be referred to as sectors. The base stations
`are communicably interconnected by a controller 120 that is
`typically coupled via gateWays to a public sWitched tele
`phone netWork (PSTN) 130 and to a packet data netWork
`(PDN) 140. The base stations additionally communicate
`With mobile terminals 102 also commonly referred to as
`User Equipment (UE) or Wireless terminals to perform
`functions such as scheduling the mobile terminals to receive
`or transmit data using available radio resources. The net
`Work also comprises management functionality including
`data routing, admission control, subscriber billing, terminal
`authentication, etc., Which may be controlled by other net
`Work entities, as is knoWn generally by those having ordi
`nary skill in the art.
`[0014] Exemplary cellular communication netWorks
`include 2.5 Generation 3GPP GSM netWorks, 3rd Genera
`tion 3GPP WCDMA netWorks, and 3GPP2 CDMA commu
`nication netWorks, among other existing and future genera
`tion cellular communication netWorks. Future generation
`netWorks include the developing Universal Mobile Telecom
`munications System (UMTS) netWorks, Evolved Universal
`Terrestrial Radio Access (E-UTRA) netWorks. The netWork
`may also be of a type that implements frequency-domain
`oriented multi-carrier transmission techniques, such as Fre
`quency Division Multiple Access (OFDM), DFT-Spread
`OFDM, IFDMA, etc., Which are of interest for future
`systems. Single-carrier based approaches With orthogonal
`frequency division (SC-FDMA), particularly Interleaved
`Frequency Division Multiple Access (IFDMA) and its fre
`quency-domain related variant knoWn as DFT-Spread
`OFDM (DFT-SOFDM), are attractive in that they optimise
`performance When assessed using contemporary Waveform
`quality metrics, Which may include peak-to-average poWer
`ratio (PAPR) or the so-called cubic metric (CM). These
`metrics are good indicators of poWer backolf or poWer
`de-rating necessary to maintain linear poWer ampli?er
`operation, Where ‘linear’ generally means a speci?ed and
`controllable level of distortion both Within the signal band
`Width generally occupied by the desired Waveform and in
`neighboring frequencies.
`[0015] In OFDM netWorks, both Time Division Multi
`plexing (TDM) and Frequency Division Multiplexing
`(FDM) are employed to map channel-coded, interleaved and
`data-modulated information onto OFDM time/frequency
`
`APPL-1013 / Page 8 of 13
`
`

`
`US 2007/0173260 A1
`
`Jul. 26, 2007
`
`symbols. The OFDM symbols can be organized into a
`number of resource blocks consisting of M consecutive
`sub-carriers for a number N consecutive OFDM symbols
`where each symbol may also include a guard interval or
`cyclic pre?x. An OFDM air interface is typically designed to
`support carriers of different bandwidths, e.g., 5 MHZ, l0
`MHZ, etc. The resource block siZe in the frequency dimen
`sion and the number of available resource blocks are gen
`erally dependent on the bandwidth of the system.
`
`[0016] In FIG. 2, the exemplary wireless terminal 200
`comprises a processor 210 communicably coupled to
`memory 220, for example, RAM, ROM, etc. A wireless
`radio transceiver 230 communicates over a wireless inter
`face with the base stations of the network discussed above.
`The terminal also includes a user interface (UI) 240 includ
`ing a display, microphone and audio output among other
`inputs and outputs. The processor may be implemented as a
`digital controller and/or a digital signal processor under
`control of executable programs stored in memory as is
`known generally by those having ordinary skill in the art.
`Wireless terminals, which are referred to as User Equipment
`(UE) in WCDMA networks, are also referred to herein as
`schedulable wireless communication entities, as discussed
`more fully below.
`
`[0017] User equipment operating in a cellular network
`operate in a number of ‘call states’ or ‘protocol states’
`generally conditioned on actions applicable in each state.
`For example, in a mode typically referred to as an ‘idle’
`mode, UE’s may roam throughout a network without nec
`essarily initiating or soliciting uplink or downlink traf?c,
`except, e.g., to periodically perform a location update to
`permit ef?cient network paging. In another such protocol
`state, the UE may be capable of initiating network access via
`a speci?ed shared channel, such as a random access channel.
`A UE’s ability or need to access physical layer resources
`may be conditioned on the protocol state. In some networks,
`for example, the UE may be permitted access to a shared
`control channel only under certain protocol-related condi
`tions, e. g., during initial network entry. Alternatively, a UE
`may have a requirement to communicate time-critical traf?c,
`such as a handover request or acknowledgement message,
`with higher reliability. In such protocol states, the UE may
`be permitted, either explicitly by the network, by design, or
`by a controlling speci?cation, such as a 3GPP speci?cation,
`to adjust its maximum power level depending on its protocol
`state.
`
`[0018] Generally, a wireless communication network
`infrastructure scheduling entity located, for example, in a
`base station 110 in FIG. 1, allocates or assigns radio
`resources to schedulable wireless communication entities,
`e.g., mobile terminals, in the wireless communication net
`work. In FIG. 1, the base stations 110 each include a
`scheduler for scheduling and allocating resources to mobile
`terminals in corresponding cellular areas. In multiple access
`schemes such as those based on OFDM methods, multi
`carrier access or multi-channel CDMA wireless communi
`cation protocols including, for example, IEEE-802.l6e
`2005, multi-carrier HRPD-A in 3GPP2, and the long term
`evolution of UTRA/UTRAN Study Item in 3GPP (also
`known as evolved UTRA/UTRAN (EUTRA/EUTRAN)),
`scheduling may be performed in the time and frequency
`dimensions using a Frequency Selective (FS) scheduler. To
`enable FS scheduling by the base station scheduler, in some
`
`embodiments, each mobile terminal provides a per fre
`quency band channel quality indicator (CQI) to the sched
`uler.
`
`[0019] In OFDM systems, a resource allocation is the
`frequency and time allocation that maps information for a
`particular UE to resource blocks as determined by the
`scheduler. This allocation depends, for example, on the
`frequency-selective channel-quality
`indication (CQI)
`reported by the UE to the scheduler. The channel-coding rate
`and the modulation scheme, which may be different for
`different resource blocks, are also determined by the sched
`uler and may also depend on the reported CQI. A UE may
`not be assigned every sub-carrier in a resource block. It
`could be assigned every Qth sub-carrier of a resource block,
`for example, to improve frequency diversity. Thus a
`resource assignment can be a resource block or a fraction
`thereof. More generally, a resource assignment is a fraction
`of multiple resource blocks. Multiplexing of lower-layer
`control signaling may be based on time, frequency and/or
`code multiplexing.
`
`[0020] The interference impact of a network entity, for
`example, a schedulable wireless communication terminal, to
`an uncoordinated adjacent band entity, referred to as the
`victim, is shown in FIG. 3. Victim entities may be base
`stations or mobile terminals in immediately adjacent bands
`or in non-contiguous adjacent bands, all of which are
`generally referred to as neighboring bands. The victim
`receiver may operate on or belong to the same or different
`technology as the network entity producing the interference.
`The victim receiver may also operate on or belong to the
`same or different network types managed either by the same
`(coordinated) operator or by a different (uncoordinated)
`operator. The victim receiver may also operate on belong to
`a different technology network where there is no coordina
`tion between networks to reduce interference.
`
`[0021] Regional or international spectrum regulatory
`authorities frequently designate contiguous segments of
`radio frequency spectrum, or radio bands for use by speci?c
`duplexing modes, for example, frequency division duplex
`ing (FDD) or time-division duplexing (TDD) or by speci?c
`wireless technologies, such as Group Special Mobile
`(GSM), Code Division Multiple Access (CDMA), Wide
`band CDMA, etc. For example, GSM networks are fre
`quently granted access to the so-called GSM 900 MHZ (or
`Primary GSM) band speci?ed as the frequency-duplex pair
`of band between the frequencies 890-915 MHZ and 935-960
`MHZ. This information may be stored in the UE or trans
`mitted by the network controlling a UE in order to permit an
`optimum choice of PA output power back-off (also referred
`to as a power de-rating) or more generally to optimally
`adjust the maximum power level of the PA conditioned on
`adjacent channel interference offered to, and consistent with,
`the known adjacent channel technologies.
`
`[0022] More generally, a frequency band adjacent to such
`a UE may be known from national or international regula
`tions or from general deployment criteria, such as ‘licensed’
`or ‘unlicensed’ designations to be subject to speci?c maxi
`mum levels of interference from the band in which the UE
`is operating. When this information is stored in the UE or
`made available by signaling from the network, the UE may
`optimiZe its radiated power level subject to the known
`adjacent band interference limits.
`
`APPL-1013 / Page 9 of 13
`
`

`
`US 2007/0173260 A1
`
`Jul. 26, 2007
`
`[0023] In FIG. 3, a schedulable entity A1306 is scheduled
`aperiodically. Particularly, the entity A1 is allocated radio
`resources including bandwidth on carrier j 310 as well as
`bandwidth location in the carrier j band. The entity A1 is also
`allocated its transmission power assignment or power
`adjustment and a scheduling grant by the base station
`scheduling entity A1302, which is part of network A.
`Schedulable entity A1306 transmits using its assigned band
`width on carrier j 310 when scheduled by BS scheduling
`entity A1302 and creates out of band emissions which
`impinge upon other carriers including an adjacent carrier j+k
`and is seen as interference 312 by BS scheduling entity
`B1304, which is the victim receiver or entity, resulting in
`reduced SNR when receiving a scheduled transmission from
`schedulable entity B1308 on carrier j+k 314. Since base
`station entity B1304 is part of Network B and there is no
`coordination, or sub-optimal coordination, between Net
`work A and Network B then it may not be possible for
`scheduling entities like 306 and 308 to avoid mutual inter
`ference.
`
`[0024] In FIG. 3, the degree to which schedulable entity
`A1306 interferes with schedulable entity B1308 on carrier
`j+k 314 is dependent on the radio frequency (RF) distance
`(also referred to as path loss) between the schedulable
`wireless communication entity and the other wireless com
`munications (victim) entity. The interference is also depen
`dent on the effective radiated power level of the transmitter,
`the siZe and amount of separation of the bandwidth alloca
`tions between entities and the amount of overlap in time. Out
`of band emissions of one transmitter will have smaller
`impact on another receiver if the path loss between the
`transmitter and victim receiver is larger, and the impact will
`be larger if the path loss is smaller. Adjacent channel
`interference is also present in TDD systems where both the
`BS 302 and schedulable entity 306 of NetworkAtransmit on
`the same carrier 310 and both BS 304 and schedulable entity
`308 of Network B transmit on the same carrier 314 and
`hence both BS 302 and schedulable entity 306 cause out of
`band emissions and hence interference 312 to adjacent
`carrier 314.
`
`[0025] In one embodiment, the radio resource allocated to
`a schedulable wireless communication entity is based on an
`interference impact of the schedulable wireless communi
`cation entity operating on the radio resource allocated. The
`interference impact may be based on any one or more of the
`following factors: a transmission waveform type of the
`schedulable wireless communication entity; a maximum
`allowed and current power level of the schedulable wireless
`communication entity; bandwidth assignable to the schedu
`lable wireless communication entity; location of the assign
`able bandwidth in a carrier band; radio frequency distance
`(path loss) relative to another wireless communications
`entity; variation in the maximum transmit power of the
`schedulable wireless communication entity for the assigned
`bandwidth; separation of assigned band relative to the other
`wireless communication entity; reception bandwidth of the
`victim entity, minimum SNR required for operation of the
`victim entity; and reception multiple access processing (e.g.
`CDMA, OFDM, or TDMA), among other factors. The
`variation in the maximum transmit power includes de-rating
`or re-rating the maximum transmit power of the wireless
`communication entity as discussed further below.
`
`[0026] For a given carrier band and band separation,
`transmissions with larger occupied bandwidth (OBW) create
`more out of band emissions resulting in a larger adjacent or
`neighbor channel leakage ratio (ACLR) than transmissions
`with smaller OBW. The increase in out of band emissions
`from transmissions with larger OBW is due largely to
`increased adjacent channel occupancy by 3rd and 5th order
`intermodulation (IM) products. The 3rd order IM product
`largely determines ACLR in adjacent bands. The 5th order
`IM product plateau largely determines ACLR in more dis
`tant (non-contiguous adjacent) bands. Note, however that in
`networks such as IEEE 802.16e-2005 and 3GPP LTE net
`works which support multiple bandwidth types, the dimen
`sions in frequency of the adjacent band would also control
`such relationships. To avoid the relative increase in ACLR
`due to larger OBW, it is generally necessary to reduce or
`de-rate transmission power created by the interfering entity
`in proportion (although not necessarily linearly so) to the
`increase in OBW. Given a reference OBW (OBWREF) with
`a known (eg 0) power de-rating (PDREF) needed to meet a
`speci?ed ACLR, an occupied bandwidth power de-rating
`(OBPD) can be de?ned for an arbitrary OBW relative to the
`reference OBW. The OBPD can be obtained empirically but
`may also be approximated mathematically by an equation
`such as:
`
`Generally, the transmission power of the mobile terminal
`must be reduced by OBPD to keep adjacent channel power
`leakage and therefore ACLR the same for a transmission
`with a larger OBW compared to one with a smaller reference
`OBW. The total power de-rating (TPD) needed to account
`for both an occupied bandwidth power de-rating (OBPD)
`and a waveform power de-rating (WPD) in order to meet a
`given ACLR requirement can be represented by:
`
`(2)
`TPD=f(0BPD, WPD)
`[0027] Note that the function f(.) may, for example, be the
`simple summation of OBPD and WPD. The WPD accounts
`for waveform attributes such as modulation and number of
`frequency or code channels and can be determined empiri
`cally through power ampli?er measurements or indicated by
`a waveform metric such as the Cubic Metric (CM). The
`additional power de-rating from OBPD (beyond WPD
`alone) generally means worse cell edge coverage for wire
`less terminals unless mitigated. For example, a transmission
`with 4.5 MHZ occupied bandwidth on a 5 MHZ E-UTRA
`carrier with a ?xed 5 MHZ carrier separation will have a
`larger measured ACLR (e.g., approximately —30 dBc instead
`of —33 dBc) with regard to the adjacent 5 MHZ carrier than
`a transmission with only 3.84 MHZ occupied bandwidth. To
`reduce the ACLR back to —33 dBc requires an OBPD of
`approximately 0.77 dB (based on empirical measurements)
`which is close to the 0.70 dB given equation (1) above based
`on OBW of 4.5 MHZ and OBWREF=3.84 MHZ.
`
`[0028] The cubic metric (CM) characteriZes the effects of
`the 3rd order (cubic) non-linearity of a power ampli?er on a
`waveform of interest relative to a reference waveform in
`terms of the power de-rating needed to achieve the same
`ACLR as that achieved by the reference waveform at the PA
`rated power. For example, a UE with power class of 24 dBm
`can nominally support a rated maximum power level
`(PMAX) of 24 dBm. In practice, the UE’s current, or
`instantaneous, or local maximum power level is limited to
`
`APPL-1013 / Page 10 of 13
`
`

`
`US 2007/0173260 Al
`
`Jul. 26, 2007
`
`the operational maximum power level given by PMAX
`f(OBPD,WPD) Where f(.) can, for example, be the simple
`summation of OBPD and WPD such that the operational
`maximum poWer level is PMAX—(OBPD+WPD). The dif
`ference betWeen PMAX and the UE’s current poWer level
`after poWer control or after assignment of an arbitrary poWer
`level less than PMAX is called the UE’s poWer margin or
`poWer headroom. Scheduling can be used to reduce or avoid
`OBPD.
`
`[0029] In one embodiment, the scheduler allocates the
`radio resource based on the interference impact by assigning
`bandWidth based on poWer headroom of the schedulable
`Wireless communication entity. Particularly, the scheduler
`?nds a bandWidth siZe that reduces OBPD enough such that
`operational maximum poWer (PMAX-OBPD-WPD) does
`not limit current poWer of the schedulable Wireless commu
`nication entity.
`
`[0030] A scheduler may control leakage into adjacent and
`non-contiguous adjacent bands by scheduling mobile termi
`nals that are “close” to the serving cell in terms of path loss
`With bandWidth allocations that occupy the entire carrier
`band or a bandWidth allocation that includes resource blocks
`(RB’s) that are at the edge of the carrier band (e.g., 5 MHZ
`UTRA or LTE carrier) since due to poWer control it is very
`unlikely that such a terminal Will be operating at or near to
`PMAX and therefore unlikely that its current poWer level
`Would be limited by the operational maximum poWer. A
`scheduler may schedule terminals that have little or no
`poWer margin With bandWidth allocations that exclude
`resource blocks at the carrier band edge therefore reducing
`OBPD and reducing the likelihood of the terminal being
`poWer limited by the operational maximum poWer. It is
`possible to preserve frequency diversity for terminals
`assigned a smaller transmission bandWidth to minimize
`OBPD by using RB hopping over a longer scheduling time
`interval composed of several frames. Signaling overhead
`may be reduced by using pre-determined hopping patterns,
`or pre-de?ned logical physical permutations. A UE Will
`determine the OBPD corresponding to its scheduled or
`allocated bandWidth siZe and location of the allocated band
`Width in the carrier band. The UE therefore computes an
`operational maximum poWer for every scheduled transmis
`sion to determine if the current poWer level Will be limited.
`
`[0031] In some embodiments, the schedulable Wireless
`communication entity obtains maximum transmitter poWer
`information based on the radio resource assignment from
`reference information stored on the mobile terminal. For
`example, the maximum transmit poWer information may be
`obtained from a look-up table stored on the Wireless termi
`nal. Alternatively, the maximum transmit poWer information
`may be obtained in an over-the-air message. Several
`examples of the relationship betWeen the radio resource
`assignment and the maximum transmit poWer adjustment are
`discussed more fully beloW. FIG. 4 illustrates exemplary
`OBPD de-rating values.
`
`[0032] A BS may execute such scheduling decisions not
`simply from considerations of interference offered by a UP,
`to frequency-adjacent BS’s, but may also simultaneously
`optimise the performance of multiple UE’s Whose allocated
`resources are derived from a common set of carrier fre
`quency resources (possibly extending over more than one
`carrier frequency). That is, the BS may optimiZing its
`
`scheduling allocations from consideration of the mutual
`interference offered betWeen a multiplicity of UE’s.
`[0033] The poWer radiated into an adjacent frequency
`band by a UE, and the distortion offered by a UE to a BS
`receiver (or other UE receiver in the case of a TDD system)
`Within the set of time-frequency resources allocated by the
`BS, is governed by several practical design criteria related to
`the implementation of mobile terminal transmitters, includ
`ing oscillator phase noise, digital-analog converter noise,
`poWer ampli?er (PA) linearity (in turn controlled by poWer
`ampli?er mode, cost, poWer consumption etc.), among oth
`ers.
`[0034] Generally, hoWever, and in common With most
`non-linear transformations expandable in terms a polyno
`mial poWer series, UE poWer ampli?ers give rise to undes
`ired adjacent band interference in broad proportion, for a
`given PA design, to the mean poWer offered to the PA input.
`As a consequence of 3rd or 5th order polynomial terms, the
`frequency at Which interference occurs is at 3 or 5 times the
`frequency of the input signal components, or harmonics
`thereof. Also, the poWer of such out-of-band components
`generally increases at 3 or 5 times the rate of increase of the
`input poWer level.
`[0035] Accordingly, mobile terminals may control their
`out of band emission levels by limiting the poWer to the PA.
`Given a speci?c rated maximum output (or input) poWer
`level designed to achieve a given level of interference into
`an adjacent frequency band, or level of in-band distortion, a
`mobile terminal may elect to adjust, for example, reduce its
`input poWer level in order to reduce such unWanted effects.
`As described elseWhere herein, a decision to increase or
`decrease the input or output PA poWer may be subject to
`other criteria, including Waveform bandWidth, location in a
`frequency band, Waveform quality metric, among others.
`[0036] Generally, attributes of the Waveform entering the
`poWer ampli?er, along With attributes of netWork or UE
`operational parameters (such as the desired level of out of
`band emissions, in-band distortion, or other criteria
`described herein) are input to a controller Which executes a
`pre-de?ned poWer adjustment function, or de-rating function
`f(x1,x2,x3, .
`.
`. ,xN) Which relates the attributes x1 etc. to a
`maximum poWer level (Where it is understood that de-rating
`may refer to a poWer level in excess, or less than, a nominal
`or rated maximum poWer level).
`[0037] In FIG. 6, a modulation and coding function 600
`accepts an information bit stream, such as higher layer
`protocol data units, and then applies techniques such as
`forWard error correction 601, modulation 609, and linear and
`non-linear spectrum shaping 605 methods prior to frequency
`conversion 607 and input to a PA 608. A controller 603 may
`derive Waveform attributes from the con?guration of the
`modulation and coding function 600 or from direct obser
`vation of the signal immediately prior to frequency conver
`sion 607. The controller 603 may also derive operational
`attributes from stored parameters or parameters signaled by
`the netWork. The controller 603 then uses the Waveform
`attributes, Which may include signal bandWidth, frequency
`location, among others, plus the operational attributes such
`as operational band, adjacent technology among others, to
`adjust the permitted maximum PA poWer value 605 Which is
`offered as a control metric to the PA 608.
`[0038] In one embodiment, the radio resource allocated to
`a schedulable Wireless communication entity is based on a
`
`APPL-1013 / Page 11 of 13
`
`

`
`US 2007/0173260 A1
`
`Jul. 26, 2007
`
`maximum power available to the schedulable Wireless com
`munication entity for the radio resource allocated along or in
`combination With other factors, for example, the interference
`impact. For a particular radio resource allocation, the sched
`uler knows the maximum transmit poWer of the correspond
`ing schedulable Wireless communication device. The sched
`uler may thus use this information to manage the scheduling
`of schedulable Wireless communication entities, for
`example, to reduce interference.
`
`[0039] In some embodiments, the scheduler determines a
`bandWidth siZe of the radio resource and allocates deter
`mined bandWidth to the schedulable Wireless communica
`tions. The scheduler may also determine Where Within a
`carrier band the assigned radio resource is located. In one
`particular implementation, the scheduler allocates band
`Width nearer an edge of a carrier band When the schedulable
`Wireless communication entity requires less transmit poWer,
`and the scheduler allocates bandWidth farther from the edge
`of the carrier band When the schedulable Wireless commu
`nication entity requires more transmit poWer. These alloca
`tions of course may depend on the interference impact, for
`example, the proximity of neighboring carrier bands among
`other factors discussed herein. In another implementation,
`the scheduler allocates a radio resource to the schedulable
`Wireless communications entity nearer an edge of a carrier
`band When a radio frequency distance betWeen the schedu
`lable Wireless communication entity and the other Wireless
`communications entity is larger, and the scheduler allocates
`the radio resource to the schedulable Wireless communica
`tions entity farther from the edge of the carrier band When
`the radio frequency distance betWeen the schedulable Wire
`less communication entity and the other Wireless commu
`nications entity is smaller.
`
`[0040] FIG. 5