(12) United States Patent
`Steer
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`USOO6845246B1
`US 6,845,246 B1
`Jan. 18, 2005
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`(10) Patent No.:
`(45) Date of Patent:
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`(54)
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`LOCATION BASED POWER CONTROL FOR
`MOBILE COMMUNICATIONS SYSTEMS
`
`Inventor: David G. Steer, Nepean (CA)
`Assignee: Nortel Networks Limited, St. Laurent
`(CA)
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 755 days.
`
`Notice:
`
`Appl. No.: 09/593,698
`Filed:
`Jun. 15, 2000
`Int. Cl." ............................ H04Q 7/20; H04B 1/00;
`HO4B 7/00
`U.S. Cl. ...................... 455/522; 455/69; 455/456.1;
`370/318
`Field of Search .............................. 455/522, 456.1,
`455/457, 63, 68, 70,422, 69; 370/317,
`318
`
`References Cited
`
`U.S. PATENT DOCUMENTS
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`5,943,610 A
`6,006.096 A
`6,011,973 A
`6,085,096 A
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`8/1999 Endo ........................... 455/69
`12/1999 Trompower ................. 455/456
`1/2000 Valentine et al. ........ 455/456.6
`7/2000 Nakamura ............... 455/456.6
`
`9/2000 Tanaka et al. ................ 455/68
`6,122,486 A
`2/2001 Takemura ................... 455/411
`6,188,883 B1
`6,201.973 B1 * 3/2001 Kowaguchi .............. 455/456.6
`6,230,017 B1 * 5/2001 Andersson et al. ...... 455/456.6
`6,337,973 B1 * 1/2002 Agin et al. ................... 455/69
`6,343,212 B1 * 1/2002 Weber et al. .....
`... 455/404.1
`6,442,393 B1 * 8/2002 Hogan ........................ 455/456
`6,490,460 B1 * 12/2002 Soliman .
`... 455/522
`6,625,455 B1 * 9/2003 Ariga ......................... 455/565
`FOREIGN PATENT DOCUMENTS
`
`7/1997 ............ HO4O/7/38
`4/1999 ............ HO4O/7/32
`
`EP
`974O1656.0
`EP
`99.107677.9
`* cited by examiner
`Primary Examiner Simon Nguyen
`(74) Attorney, Agent, or Firm-Borden Ladner Gervais
`LLP, Dennis R. Haszko
`(57)
`ABSTRACT
`A method and apparatus for facilitating power control within
`mobile radio Systems. The power control is a function of
`location of the mobile station. Power levels are mapped to
`a geographic grid and power levels are Set based upon Such
`pre-determined power levels. Alternatively, initial power
`levels are Set based upon the mapped power levels, but are
`Subject to fine tuning through a much reduced feedback
`loop.
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`3 Claims, 5 Drawing Sheets
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`POWer
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`

`1
`LOCATION BASED POWER CONTROL FOR
`MOBILE COMMUNICATIONS SYSTEMS
`
`US 6,845,246 B1
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`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`The present invention involves power control enhance
`ment within mobile communications Systems. Moreover, the
`present invention addresses problems associated with Setting
`power levels. More Specifically, the present invention
`defines a preferred method for Setting the power based upon
`the geographical location of the mobile Station.
`2. Description of the Prior Art
`Power control is key to the Successful operation of radio
`access technology Such as Code Division Multiple AcceSS
`(CDMA). CDMA systems rely on strict control of power at
`the mobile station to overcome the “near-far problem” that
`occurs when the interfering Signal is significantly Stronger
`than the desired Signal and Such an interfering Signal would
`then jam the weaker Signal. If the Signal from a mobile
`station were to be received at the cell site receiver with too
`much power, that particular mobile Station would then
`overload that receiver. This would overwhelm the signals
`from the other mobile stations. The goal of CDMA is to have
`the Signals of all mobile Stations arrive at the base Station
`with as exactly similar power as possible. The closer the
`mobile station is to the cell site receiver, the lower the power
`necessary for transmission. On the other hand, the further
`away the mobile Station, the greater the power necessary for
`transmission. Accordingly, two forms of adaptive power
`control are typically employed in CDMA systems. These
`include open-loop and closed-loop power control.
`Open-loop power control is based on the Similarity of loSS
`in the forward and reverse paths. The received power at the
`mobile station is used as a reference. If it is low, the mobile
`Station is assumed to be far from the base Station and
`transmits with high power. If it is high, the mobile Station is
`assumed to be near the base Station and transmits with lower
`power.
`Closed-loop power control is used to adjust the power
`from the mobile Station from the open-loop Setting. This
`adaptive process adjusts the power from the initial open
`loop Setting to match the power needed for the mobile's
`current location and the current radio propagation condi
`tions. This is achieved by an active feedback system from
`the base Station to the mobile Station. AS an example, power
`control bits may be sent every 1.25 ms to direct the mobile
`Station to increase or decrease its transmitted power by 1 dB.
`Lack of power control to at least this accuracy greatly
`reduces the capacity of CDMA systems.
`With these adaptive power control techniques, the mobile
`Station transmits only enough power to maintain a link. This
`results in an average power requirement that is much lower
`than that for analog Systems, which do not usually employ
`Such techniques. CDMA's lower power requirement trans
`lates into Smaller and lightweight mobile terminals, longer
`life of batteries and makes possible, lower-cost handheld
`computers and wireleSS computercommunications devices.
`Within mobile communications Systems and especially
`Such Systems having high traffic, the radio power must be
`kept to the minimum necessary to maintain the desired error
`rate for the communications link. Using the lowest amount
`of radio power minimizes the interference to other calls and
`thereby maximizes the traffic-carrying capability of the radio
`System.
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`The total power required for a radio link in the typical
`terrestrial radio environment is a complicated Statistical
`function of the environment and the distance as is known in
`the art. Thus the power cannot be directly calculated from
`the distance, as it is Subject to additional losses. These are
`often Summarized as “fading” and "shadowing.” Fading is
`extra loSS due to the combination at the receiver of reflected
`Signals from the environment and the motion of the trans
`mitter or receiver or objects in the environment. Shadowing
`is extra loss due to obstructions (e.g., buildings) between the
`transmitter and the receiver. Further details of radio propa
`gation modeling can be found, for example, in Chapter two
`of Gordon L. Stuber's book “Principles of Mobile Commu
`nication” published by Kluwer Academic
`While fading loss may vary rapidly with time (due to
`movement of the mobile or objects in the environment), the
`Shadowing loSS is relatively constant with time and only
`varies (often abruptly) as the mobile moves into or out of the
`Shadowed region. Because the radio channel conditions vary
`over time due to fading and Shadowing, the radio power is
`typically adjusted with a feedback control loop (as men
`tioned above) between the transmitter and the receiver. In
`traditional Systems, the transmitter and the receiver
`eXchange Signaling messages to adjust the power level to the
`minimum needed for the desired error ratio. Such requisite
`levels and ratioS are found in the Telecommunications
`Industry Association (TIA) standards IS-95 or IS-2000. This
`Signaling involves a two-way flow of information between
`the base Station and mobile Station in order to Send the power
`control messages. However, this two-way flow is not always
`possible, particularly during call Set-up and for one-way data
`flows prevalent in data transfer and Signaling. In these latter
`cases, it would be advantageous to have another means of
`adjusting the power to the optimum level rather than the
`extensive open and closed loop control processes described
`above.
`
`SUMMARY OF THE INVENTION
`It is desirable to obviate or mitigate one or more of the
`above-identified disadvantages associated with Setting
`power control in a mobile communications System. The
`present invention proposes a technique of Setting the power
`based on the location of the mobile station. Such location
`based power control may be done with Significantly reduced
`or eliminated need for the traditional feedback control loop
`processes. Accordingly, the present invention is valuable for
`one-way traffic flows and highly suitable for short burst
`transmissions that are not long enough for the control loop
`to lock such as for Internet Protocol (IP) or signaling data
`packets.
`The present invention includes a method for location
`based power control within a mobile communications Sys
`tem. The method includes determining a plurality of location
`data objects each being a geographical location that corre
`sponds to a portion of a mobile communications coverage
`area; determining a plurality of power value data objects
`each being a nominal transmit power level that corresponds
`to one of the location data objects, Storing, within a database
`used by a power control process, a map having a data
`Structure that includes the plurality of location data objects
`and the plurality of power value data objects, adjusting a
`transmit power for a mobile Station according to a location
`of the mobile Station correlating to the data Structure in the
`map; and updating the plurality of power value data objects.
`The present invention includes a computer data Signal
`embodied in a mobile radio System. The Signal includes a
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`Source code Segment for determining a location of a mobile
`Station; a Source code Segment for determining a power
`value data object corresponding to the location of the mobile
`Station; and a Source code Segment for Setting a transmit
`power level of the mobile Station according to the power
`value data object corresponding to the location of the mobile
`Station.
`The present invention includes a map for acceSS by an
`application program being executed on a mobile communi
`cations System. The map including a data Structure Stored in
`the map, the data Structure including information resident in
`a database used by the application program and including a
`plurality of location data objects each being a geographic
`location corresponding to a portion of a mobile radio cov
`erage area. The application program can be a power control
`process of the mobile communications System and the data
`Structure also includes a plurality of power value data
`objects. The power value data objects can each include a
`nominal transmit power level that corresponds to one of the
`location data objects. Each of the power value data objects
`can further include a received signal value and a Statistical
`variance value that represents the Standard deviation of the
`received Signal value and a nominal transmit power level
`corresponding to the received Signal value. Accordingly, the
`map Stores location-based power control data for access by
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`an application program being executed on a mobile com
`munications System. This map information is used together
`with the location of the mobile to help set the radio trans
`mission power level at initial call Setup, for one way traffic
`flows or for other conditions in which closed loop power
`control techniques are not Suitable.
`In the present invention, the map database resides on
`either a network Side of the mobile communications System
`or on a mobile Side of the mobile communications System.
`Alternatively, the location of the mobile Station may
`provide useful information in a variety of operating Sce
`narios. For instance, location information may be useful in
`handoffs at the boundaries of coverage between Systems.
`This may occur, for example, at the boundary of territory
`between coverage of two adjacent operators, or at the
`boundary of the coverage of one System (e.g. a third gen
`eration system such as 3G-UTRAN) and another (e.g.
`GSM). The boundary may also be between Frequency
`Division Duplex mode (FDD) and Time Division Duplex
`(TDD) operating modes of the 3G-UTRAN (or other) sys
`tem. AS the location of the mobile is seen to approach the
`region boundary, negotiations can begin with the adjacent
`network or subsystem to effect a smooth handoff to the new
`system. This may be appropriate both for handoffs to like
`Systems (e.g. ones utilizing the same air interface) as well as
`to alternate Systems (those utilizing a different air interface).
`In this latter case, the location information can be especially
`helpful as it enables the mobile (and the adjacent network)
`to be alerted to look out for radio Signals in the new mode.
`For example, this can be used for transitions from the 3G
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`system to GSM (and vice-versa) and also between areas of
`wide area Systems and indoor Systems that may be part of the
`3G-UTRAN deployment (e.g. FDD and TDD modes).
`Furthermore, location information may be used at initial
`call Set-up from mobiles near a System coverage boundary to
`assure the appropriate System operator picks up the call. AS
`there is frequently considerable co-coverage at the Service
`boundaries and operators are often constrained by regulation
`to accept traffic only from within their licensed territories,
`this is an important service application. With the availability
`of data and multi-media Services in the third generation
`mobile Systems, Some calls may require considerable
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`resources. A call may require, for example, Signaling, Speech
`and high data rate Stream and packet Services all at once. For
`Such a mobile requesting a handoff, the network may, or may
`not, be fully able to accommodate all the Service require
`ments at the new (target) base Station. Information about the
`location of the mobile can be used to assure that the handoff
`is being set-up to the right base Station (e.g. the one closest
`one to the mobile's path). The new call may also be partly
`accepted by a plurality of base Stations that are nearby to the
`mobile's location, but are individually unable to accommo
`date the full requested Services and can accommodate the
`Service request in Summation.
`There are both radio communications to Set-up, and also
`landline network channels needed to accommodate the Vari
`ety of traffic. Packets may need to be re-routed and buffered
`at the target base Station. This may require adjusting the
`existing traffic at the new base Station. Traffic may be
`offloaded from other mobiles that are known to be in
`locations that can be Serviced by other nearby base Stations
`and thereby release resources for the handoff. Also, the
`mobile's traffic could be Serviced by Splitting it among
`Several new base Stations with complimentary coverage,
`rather than being forced exclusively to one new base Station.
`This form of distributed resources handoff may also be used
`at call origination to Spread the new load over Several base
`Stations and network connections. This is not possible with
`out knowledge of the location of the mobile as one can’t
`really be Sure from the Signal Strength which of Several
`alternate base Stations might be Suitable to share the traffic.
`More simply, if the base station initially selected to receive
`the call has insufficient resources to accommodate the addi
`tional call, then the location information can be used to defer
`or deflect the call Set up or handoff to an alternate nearby
`base Station to continue the call until the initial base Station
`becomes available. This reduces the incidence of lost calls
`through traffic overloads.
`Another use of location information is relevant to pre
`venting fraudulent use of mobile phones, as it is an unfor
`tunate aspect of network operations. The availability of
`location information, particularly at call origination time,
`can be used to help Sort out the legitimate and illegitimate
`operation of a mobile unit. It may also be expected to reduce
`the usage of Stolen phones if it becomes well known that
`they can be tracked when in use. This information may be
`passed to the law enforcement authorities for action, or to
`monitor movements.
`While Such varied use of location information of the
`mobile is possible, the present invention is focused on power
`control processes that utilize Such location information. This
`focus is due to the fact that the radio power loSS due to the
`path distance is the biggest component of the radio link
`budget. In an ideal System, Simply using the base Station
`closest to the mobile Station ensures that minimum power is
`used for transmission. The transmission path loSS may be
`approximately derived from information including the loca
`tion of the mobile Station, the location of the Serving base
`Station, and the computed distance between the two. Further,
`contemporary mobile communications Systems include the
`Standardized capability to determine the location of the
`mobile Station-e.g., the Telecommunications Industry
`Association (TIA) standard IS-95 and the European Tele
`communications Standards Institute (ETSI) standard for
`Global System for Mobile communications (GSM). The
`mobile Station location may be determined by means of the
`given communications System's Standard technique or alter
`natives Such as the use of a navigation System like the Global
`Positioning System (GPS). It should be understood that the
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`location of the mobile station may be determined by any
`Suitable locating technique without Straying from the
`intended Scope of the present invention.
`The present invention is in Sharp contrast to the known
`Straight-line distance approach or triangulation methodology
`that is more appropriate in ideal terrain (i.e., flat and open
`areas). According to the present invention, the radio power
`levels within the radio system are set via a map (or table).
`Such a map includes Suitable power levels for locations
`within the coverage region regardless of terrain type. The
`map may be developed in Several ways. One way would be
`for measurements to be made in a Survey (e.g., when the
`network is installed). The Survey results, in the form of a
`map or table, are stored in the power control processor (i.e.,
`server) associated with the mobile network. Measurements
`would be made at practical locations in a roughly grid
`pattern throughout the coverage area.
`Alternatively, a dynamically generated map can be cre
`ated. In Such a situation, the network of base Stations would
`be installed and operated as is typical. AS connections (i.e.,
`Successful calls) are made with mobile Stations in normal
`use, the power levels used (normalized to Standard bit rate
`and error rate) along with the related location information
`would be stored in the map. Over time, this technique would
`dynamically build up a map of power levels in the most
`utilized locations. This latter technique has the advantage
`that as the radio propagation conditions vary over time as the
`environment changes (e.g., new buildings are added . .
`.
`etc.), the map is automatically updated to the latest condi
`tions. Moreover, it is advantageous to combine the initial
`Survey map with the dynamic updating through usage Such
`that implementing the invention is accomplished quickly
`and the benefits of the invention increase over time via the
`dynamic updating.
`Together, the inventive techniques for using the location
`information for power control provide Smoother and more
`accurate level control for packet and wide bandwidth Ser
`vices. This helps to deliver higher traffic capacity and
`revenues through the optimum allocation of network
`resources. Other aspects and features of the present inven
`tion will become apparent to those of ordinary skill in the art
`upon review of the following description of Specific embodi
`ments of the invention in conjunction with the accompany
`ing figures.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a diagram showing a mobile communications
`System utilizing the present invention.
`FIG. 2 is a block diagram showing a mobile Station
`including location based power control according to the
`present invention.
`FIG. 3 is a block diagram showing a base Station includ
`ing location based power control according to the present
`invention
`FIG. 4 is a flow diagram showing the power adjustment
`process according to the present invention.
`FIG. 5 is a flow diagram showing the map update process
`according to the present invention.
`DETAILED DESCRIPTION OF THE
`INVENTION
`The present invention includes an apparatus and method
`using location information for power control. The inventive
`method is realized through System enhancements that Store
`updated information to assist in rapidly Setting power levels
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`for any given geographical location. Such System enhance
`ments are shown in FIG. 1.
`With reference to FIG. 1, a mobile radio system is shown
`utilizing the present invention. Moreover, a number of base
`Stations 11a–11c and mobile Stations 12 are interconnected
`through a mobile communications network 10. It should be
`understood that, while only a few are shown, any number of
`mobile stations 12 and base stations 11a–11c may be
`involved. As well, the network 10 may involve any standard
`configurations like GSM, 3G UMTS, or IS-41. Inside the
`network 10 are communication links, as well as control and
`Switching apparatus. Such apparatus controls the mobile
`radio System operation and delivers calls (i.e., user traffic)
`and Signaling to the mobile Stations 12 via the base Stations
`11a–11c. The details of this operation are well known and
`beyond the Scope of this discussion.
`The mobile Stations 12 move about in the coverage area
`of the base stations 11a–11c and communicate with these
`base stations 11a–11c. These mobile stations 12 may, in turn,
`communicate with other mobiles (not shown) or other
`devices (e.g., wired telephones- not shown) attached to the
`network 10. The mobile radio system of FIG. 1 also includes
`a power control map 13, a power control process 14, and a
`location process 15 as parts of (or attached to) the network.
`The location process 15 is representative of the process that
`serves to determine the location of the mobile stations 12.
`The location process 15 may be part of the network 10, the
`base station controllers within the network 10, or (e.g. if it
`is a GPS technique) may be located in the given mobile
`station 12.
`The power control proceSS 14 is representative of the
`process that is used to control the transmitter power. For
`downlink transmissions, the power control process 14 may
`be part of the base station 11a–11c, the base station con
`trollers within the network 10, or it may be a separate server
`communicating with the radio transmitters through the com
`munications network. The power control proceSS 14 is
`preferably realized in Software controlling the radio trans
`mitter operations. For the uplink, the power control process
`14 is preferably part of the transmitter control process of the
`given mobile Station 12. This may occur via Software
`operating in either or both of the microcontroller and Digital
`Signal Processor (DSP) of the mobile station 12. The power
`control process 14 using the power control map 13 to Set the
`power level will preferably be implemented as an addition to
`the otherwise existing proceSS in the microcontroller and/or
`DSP in the mobile station 12 or the power control process 14
`in the base station 11a–11c, the base station controllers
`within the network 10, or a separate server.
`The power control map 13 is preferably developed via an
`initial Survey with updating. That is to Say, when the network
`10 is installed, initial measurements would be taken of the
`power level required at each one of Several practical loca
`tions throughout the coverage area. The Survey results, in the
`form of a map or table, are then Stored in the Server
`associated with power control for the network 10 So as to
`form the power control map 13. Preferably, these survey
`results are made utilizing a two-way link at a nominal bit and
`error rate. The two-way link would be established, for
`example, between a measuring mobile Station 12 and the
`given base station 11a–11c. Next, the location of the mea
`Surement is determined. Thereafter, the average power trans
`mitted and received would be recorded for Storage in the
`power control map 13 along with the corresponding loca
`tion. The Statistical Standard deviation of the measurements
`related to the power transmitted and received may also be
`Stored in the power control map 13. After Such an initial
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`Survey, the power control map 13 will thus contain mea
`Surements at relatively diffuse locations in a roughly grid
`pattern. Greater accuracy in mapping the power control data
`is accomplished via updating.
`According to the present invention, dynamic updating of
`the power control map 13 occurs as connections with mobile
`Stations 12 are made during normal use (e.g., Successful calls
`or data links). Preferably, each Successful connection from
`normal use results in the power levels used (normalized to
`Standard bit rate and error rate) along with the related
`location information being Stored in the power control map
`13. Such updating over a time period adds to the initial
`Survey data in Such a manner that required power levels for
`normal use in the most utilized geographic locations
`dynamically accrue within the power control map 13.
`The power control map 13 Stores the nominal (average)
`transmit power required, the value of the received signals,
`and a measure of the Statistical variance of these quantities
`such as the standard deviation. It should be readily under
`stood that a number of related values may also be stored for
`each location depending on bit and errors rates of available
`Service. These Stored values may be used as a basis for
`calculating the required power based on Services and local
`conditions as discussed in the following paragraphs.
`AS mentioned before, the power control process 14,
`power control map 13, and location proceSS 15 may be
`resident within the network 10 at any appropriate point. The
`inclusion of the power control map 13, power control
`proceSS 14, and location proceSS 15 may be possible and
`occur solely within the mobile station 12 as discussed with
`respect to FIG. 2. However, a more advantageous arrange
`ment would be that the power control map 13 and location
`process 15 be independent of the power control process 14
`and resident outside of the mobile Station 12 as is discussed
`with respect to FIG. 3.
`Alternatively, the power control map 13 would be held in
`the network 10 and be updated and shared for use by all
`mobile stations 12 within the network 10. The power control
`process 14 would involve both the mobile station transmitter
`and the base station receiver (or Vice versa). The location
`process 15 may be shared between the mobile and base
`station or the network (e.g., GPS).
`FIG. 2 shows a block diagram of the present invention
`within the mobile station 12 from FIG. 1. In this
`arrangement, the Signaling decoder 23, as well as other parts
`26 of the mobile, receives and interprets the Signaling
`messages received from the radio receiver 22 of the mobile.
`The Signaling decoder 23 decodes the map information to be
`used by the power control proceSS 24. The power control
`proceSS 24 makes use of information about the location and
`the map/table information placed in Storage 24a to adjust the
`power of the transmitter 21 via the transmitter power adjust
`ment 25. There are several ways to adjust the power level
`that are well known. As an example, one of these is to add
`attenuation to reduce the Signal level. Another is to reduce
`the Voltage applied to the amplifier circuit and thereby
`reducing the transmitted power. The received signal and the
`power control process 24 are also connected to other parts of
`the mobile station for other control purposes 27 which are
`not detailed herein as they are beyond the Scope of this
`invention. The power control process 24 may also take input
`28 from other parts of the mobile station to include other
`operating conditions, Such as the user desired bit and error
`rateS.
`In FIG. 2, the mobile is assumed to receive map and
`location information via the Signaling decoder 23. Such
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`information is combined in the power control proceSS 24 to
`adjust the transmmiter power. It should be noted that the
`map information could be broadcast from the base Station
`and Stored in the power control proceSS in the mobile while
`the location information could come from a GPS unit 29 in
`the mobile. For the mobile station to make use of the power
`control map information for its uplink transmissions (i.e.,
`transmissions in the direction from the mobile Station to the
`network base station), the map information must be made
`known to the mobile station.
`While these elements as shown in FIG. 2 are shown as
`Separate items, it should be understood that they would
`typically be a part of the Software process that already is
`Supervising the operation of the mobile Station. AS Such, the
`power control map or local parts of it may be Stored within
`the power control process 24a. Alternatively, the power
`control process 24 could also include Software that operates
`from the controller of the base stations in the mobile
`network. In Some Systems, there may be Several power
`control algorithms in effect within the processor Software
`and Some of these may also operate in the base Station
`controller.
`Within the present invention, the “nominal' values of
`transmitter power Stored in the power control map are used
`as the basis for Setting the transmitter power. Two important
`conditions affect the actual power needed for transmissions.
`One of these is the desired bit and error rates, and the other
`is the Shadowing compensation. In order to maintain a
`desired bit and error rate, Sufficient power must be trans
`mitted to deliver enough energy per bit of data to the
`receiver. This must be sufficiently above the noise level for
`the radio modulation (and coding) technique being used to
`achieve the desired error rate (e.g., 4-QAM modulation
`requires a Signal to noise ratio of about 10 dB to achieve an
`error rate of 10° in a Gaussian channel). In modern radio
`Systems, the Subscriber may Select the desired bit rate. Thus,
`the transmitter power will be determined by the user's needs
`with more power being needed for higher bit rate Services.
`In Such a situation, the nominal transmitter power values
`Stored in the power control map might be in units of
`“milliwatts per bit/second.” The value from the power
`control map would then be multiplied by the user selected bit
`rate to give the required transmitter power for the location
`and the Service.
`Another aspect of Setting the transmitter power is the error
`correction coding Selected. Different Services Selected by the
`user may utilize different correct