Abstract:
A system and method in a wireless communication system having plural base stations ( 10   a,    10   b,    10   c ) and a MSC ( 45 ) with a network overlay geo-location system.

Description:
CROSS REFERENCES 
       [0001]    The present application is co-pending with and claims priority benefit of provisional application entitled “Geolocation of Mobile Appliances”, Appl. S.N. 60/418,342 and filed on Oct. 16, 2002, the entirety of which is hereby incorporated herein by reference. 
         [0002]    The present application is related to and concurrently filed with applications titled “A SYSTEM AND METHOD FOR ENHANCING THE ACCURACY OF A LOCATION ESTIMATE” SN #, “WIRELESS COMMUNICATION NETWORK MEASUREMENT DATA COLLECTION USING INFRASTRUCTURE OVERLAY-BASED HANDSET LOCATION SYSTEMS” SN #, “NETWORK OVERLAY LOCATION SYSTEM AND METHOD FOR AIR INTERFACE WITH FREQUENCY HOPPING” SN #, “A SYSTEM AND METHOD FOR ESTIMATING THE MULTI-PATH DELAYS IN A SIGNAL USING A SPATIALLY BLIND ANTENNA ARRAY, SN#, and “SYSTEM AND METHOD FOR OPERATING A NETWORK OVERLAY GEO-LOCATION SYSTEM WITH REPEATERS” SN #, filed Oct. 16, 2003,the entirety of each of these applications is incorporated herein by reference. 
     
    
     BACKGROUND 
       [0003]    Applicant&#39;s disclosure is directed to a wireless communications network overlay for determining the location of mobile appliances. 
         [0004]    The use of wireless communication devices such as telephones, pagers, personal digital assistants, laptop computers, etc., hereinafter referred to collectively as “mobile appliances”, has become prevalent in today&#39;s society. Recently, at the urging of public safety groups, there has been increased interest in technology which can determine the geographic position, or “geo-locate” a mobile appliance in certain circumstances. For example, the Federal Communication Commission (FCC) has issued a geo-location mandate for providers of wireless telephone communication services that puts in place a schedule and an accuracy standard under which the providers of wireless communications must implement geo-location technology for wireless telephones when used to make a 911 emergency telephone call (FCC 94-102 E911). 
         [0005]    In addition to E911 emergency related issues, wireless telecommunications providers are developing location-enabled services for their subscribers including roadside assistance, turn-by-turn driving directions, concierge services, location-specific billing rates and location-specific advertising. 
         [0006]    To support FCC E911 rules to locate wireless 911 callers, as well as the location enabled services, the providers of wireless communication services are installing mobile appliance location capabilities into their networks. In operation, these network overlay location systems take measurements on RF transmissions from mobile appliances at base station locations surrounding the mobile appliance, and estimate the location of the mobile appliance with respect to the base stations. Because the geographic location of the base stations is known, the determination of the location of the mobile appliance with respect to the base station permits the geographic location of the mobile appliance to be determined. The RF measurements of the transmitted signal at the base stations can include the time of arrival, the angle of arrival, the signal power, or the unique/repeatable radio propagation path (radio fingerprinting) derivable features. In addition, the geo-location systems can also use collateral information, e.g., information other than that derived for the RF measurement to assist in the geo-location of the mobile appliance, i.e., location of roads, dead-reckoning, topography, map matching etc. 
         [0007]    In a network-based geo-location system, the mobile appliance to be located is typically identified and radio channel assignments determined by (a) monitoring the control information transmitted on radio channel or wire line interface for telephone calls being placed by the mobile appliance to detect calls of interest, i.e., 911, (b) a location request provided by a non-mobile appliance source, i.e., an enhanced services provider. Once a mobile appliance to be located has been identified and radio channel assignments determined, the location determining system is first tasked to determine the geo-location of the mobile appliance, and then directed to report the requesting entity or enhanced services provider. 
         [0008]    The monitoring of the RF transmissions from the mobile appliance or wire line interface to identify calls of interest is known as “tipping”, and generally involves recognizing a call of interest being made from a mobile appliance and collecting the call setup information. Once the mobile appliance is identified and the call setup information is collected, the location determining system can be tasked to geo-locate the mobile appliance. 
         [0009]      FIG. 1  shows a conventional mobile-appliance communication system having a mobile switch controller  45  connected to base stations  10  for communicating with a mobile appliance  20 . Each base station  10  contains signal processing equipment and an antenna for transmitting to and receiving signals from the mobile appliance as well as other base stations and centrally located control and processing stations. A mobile appliance location determining sensor  30  may be positioned at some or all of the base stations  10  to determine the location a mobile-appliance within the signal coverage area of the communication system. The antenna may be a multi-element antenna. 
         [0010]    A network overlay system is generally composes of two main components, one that resides at the base station that makes measurements on the RF signal emanating from the wireless device, the wireless location sensor  30  and one that resides at the mobile switch that tasks the wireless location sensor groups to collect data and then uses the data to compute a location estimate, this component generally referred to as the Geolocation Control System (GCS)  50 . In the normal course of operation, the GCS is tasked by an outside entity to generate a location estimate on a particular mobile appliance. The tasking is accompanied by information on the mobile of interest including the serving base station and sector for the call and the RF channel (frequency, time slot, CDMA code, etc.) being used by the wireless communications network to complete the wireless connection. Once the GCS receives this tasking, based on the serving sector, it tasks a set of WLS units to make measurement on the RF emission of the mobile. The WLS units make the measurements, and report them to the GCS. The GCS then computes a location estimate using some mathematical or data matching algorithm. Alternatively, RF or wired links containing control channels used to set up calls in the wireless network can be scanned to detect the placement of a call of interest. The signaling that occurs on an RF control channel can be used to determine location, or RF traffic channel parameters can be extracted from the control channel messaging to determine which traffic channel to use for location related measurements 
         [0011]    The signal reception area of a base station is generally divided into sectors of various orientations depending on the type of antenna configuration and signal processing equipment.  FIG. 2  shows a typical base station coverage area divided by sectors each with a 120 degree bandwidth. The mobile appliance communication system is designed so that the mobile appliance preferably has the capability to communicate with at least one base station while in the coverage area. 
         [0012]    The capability of the base stations to receive signals from the mobile appliance is base on a number of factors such as geographic location of the base station with respect to the location of the mobile appliance, the height of the antenna, the number of sectors and the orientation of the sectors. 
         [0013]    To meet the ever growing demand for mobile communication, wireless operators are using smart antennas to unlock fixed cell site sectorization to manage and distribute traffic loading more effectively. The geographic distribution of traffic across a network even within a single cell varies considerably, in a typical three sector cell as shown in  FIG. 2 , the traffic density in the most heavily loaded sector  201  is often more than twice that in the least-loaded sector  203 . 
         [0014]    As a result, some cells may have sectors that are fully loaded and where traffic is blocking up, while other sectors of the same cell are well below peak loading and have spare capacity, On a larger scale, high traffic areas such as highway interchanges, urban centers and shopping centers create hot spots that strain capacity even while other network resources go unused in low-traffic areas. This variability in the traffic density creates network inefficiencies which have economic effects on the wireless operators. 
         [0015]    The use of smart antennas allow wireless operations to control and optimize coverage with flexibility and precision. Again, working within a three 3 sector configuration, operators can adjust sector orientation by pointing angles in 30 degree increments, select from beam widths of 60, 90, 120, 180 and 240 degrees, and change gain settings to expand or contract coverage in highly localized areas, without the expense of a custom antenna. 
         [0016]    Using this flexible configuration options of smart antenna, operators can tailor a cell&#39;s coverage to fit its unique traffic distribution, thus operators can significantly benefit from matching usage levels with an appropriate sector beam width. A relatively narrow beam width 30 degrees to 60 degrees horizontal, for instance might cover a heavy handoff area or a highway corridor, while a moderate beam width 90 degrees horizontal might serve a suburban or light urban area. In low traffic areas such as mountains, water or rural environments antennas with wider bandwidths can provide the most effective use of network resources. 
         [0017]    Operators also can use smart antennas to respond quickly to time varying traffic patterns. Using the system&#39;s operation and administration software, operators can adjust sector configurations on demand and within minutes. As a result, operators can modify a cell&#39;s operation based on the time of day or day of the week, or to accommodate and anticipated surge in call volume from a sporting or community event. 
         [0018]    Operators using smart antennas to change the size or orientation of sectors can shift the traffic load from an overtaxed sector to one or more underused sectors, thus in effect, routing network capacity where and when it is required. For example, a comparison can be made between  FIG. 2  where conventional sectors are illustrated and  FIGS. 3   a  and  3   b  illustrating the controllable sectors enabled with the use of a smart antenna. In  FIG. 2  traffic loads across the three sectors vary greatly, with a single sector  201  handling traffic for the office park  211  and most of the residential area  212 . By contrast, the cell&#39;s sectors in  FIGS. 3   a  and  3   b  have been resized and reoriented to the traffic load is more evenly distributed among the three sectors. Each sector&#39;s beam width has been altered to best accommodate the peak traffic load in that sector. In  FIG. 3   a  the narrow sector  301  covering the office park  211  maximizes capacity for a high traffic area, while the relatively wide sector  303  covering the water  214  provides adequate capacity for a low-traffic area. And as shown  FIG. 3   b , the sectors can be redefined to provide narrow sector  303  coverage to the football stadium  215  when a large event is taking place. 
         [0019]    Smart antennas refer to antennas that spatially steer or switch beams or nulls, or dynamically reallocate available RF channels to different sectors in a base station. In general, they do this as a function of the loading on the base station, or based on the direction of arrival of the RF energy from mobile appliances. The purpose of these functions as discussed above is to extend base station range, improve signal quality, and/or increase the number of users served by the base station. Smart antennas are generally made up of antenna arrays, and accompanying electronics boxes.  FIG. 4  shows the principal system elements of a smart antenna. The smart antenna  400  typically consists of a sensor array  401 (antenna array), a pattern-forming network  410  and the adaptive processor  413 . The pattern-forming network  410  and the adaptive processor  413  make up the electronic box referred to earlier. The antenna array  401  consists of N antennas  402  designed to receive (and transmit) signals. The physical arrangement of the array (linear, circular, etc.) is arbitrary, however, the physical arrangement fundamentally dictates the capability of the smart antenna  400 . The output of each of the N antenna element  402  is fed into the pattern-forming network  410 , where the outputs are processed by filters  411 . These filters determine the directional pattern of the smart antenna. The outputs of the filters  411  are then summed  412  to form the overall output y(t). The complex weights of the filters  411  are determined by the adaptive processor  413 . 
         [0020]    Smart antennas can operate on either the forward link, reverse link, or both. Smart antennas can be a part of the base station hardware supplied by the infrastructure vendor, or an appliqué supplied by a third part vendor. In general, the operation of the smart antenna (null/beam steering/switching or channel sector switching) is not known to the rest of the host base station or the wireless infrastructure. 
         [0021]    Network overlay location systems typically locate a mobile appliance on the traffic channels of a wireless network. The system typically uses sensors employing techniques of time difference of arrival (TDOA) supplemented with Angle of Arrival (AOA) in some cases to perform a multi-site location computation. The traffic channel assignment information is provided through a separate process, with one option being a wire line interface between the MPC  40  and the GCS  50  ( FIG. 1 ) providing MOBINFO (IS- 41  Mobile information) parameters passed by the Mobile Positioning Center (MPC)  40  ( FIG. 1 ) as part of the GPOSREQ (J-STD-036 Geolocation Position Request) message. Another option for the traffic channel assignment data is the wire line interface  41  between the base stations and the mobile switch center (MSC)  45 . Neither the base station  10  nor the switch knows that a smart antenna is serving a call. Therefore the GPOSREQ information from the MPC is not able to alert the Geolocation system that a smart antenna is in use. Geolocation systems locate the transmitter using the corresponding MOBINFO parameters passed from the MPC  40 . In the case of a mobile served by a smart antenna, information provided to the location system by the MPC on the serving sector may or may not be accurate. The smart antenna may have moved the RF channel from the original serving sector to another to accommodate current traffic needs, or could have spatially steered a beam or null that moves the original coverage of area of a sector to a new geographic area. The overall affect of these smart antenna functions is that the mobile of interest may or may not be in the original geographic area defined by the sector communicated to the location system by the MPC  40  which can frustrate the geo-location process. 
         [0022]    For example,  FIG. 5   a  shows a communication system with  7  base stations and their associated overage areas  501 . A base station  510  is designated to operate in a three-sector mode (A  511 , B  512 , and C  513 ). The infrastructure equipment (mobile switch, not shown) contains data that indicates what RF channels are mapped to what sectors at the base station  510 . In the example shown channels u and v, w and x and y and z are mapped (assigned) to sectors A  511 , B 512  and C  513  respectively. Without a smart antenna operating, when a mobile  500  is provided service on a traffic channel, the sector serving the mobile would be known by the mobile switch (sector A  511 ) based on the assigned RF channel/traffic channel (channel v). The geo-location system would task sensors in the vicinity of the serving A sector area, namely sensors in sector  523  of base station  520 , and sector  532  of base station  530  to locate the mobile. Other sectors can also be tasked on their vicinity to the serving sector, however only the two closest are shown for clarity of illustration. 
         [0023]    If a smart antenna is operating at base station  510 , then the smart antenna can move the assigned RF channel, z from sector C  513  to another sector A  511  through an RF switch in the smart antenna to accommodate extra traffic seen on the A sector  511  for this time of day (perhaps a major commuter route is served by the A sector  511 , and additional RF channels are allocated to serve it by taking channels from the C sector  513 ). Prior art geo-location systems attempt to locate the mobile by tasking sensors around the C sector  513 , since z is mapped to C, and the smart antenna and its dynamic allocation of channels and variations in sectors is invisible to the base station and the MPC. The sensors in sector  542  of base station  540  and sector  551  of base station  550  as shown in  FIG. 5   b  would be tasked to locate the mobile  500 . Thus a poor or perhaps no location would be estimated because the sensors tasked are not the one in proximity to the actual location of the mobile appliance. 
         [0024]    Similarly as shown in  FIG. 5   c , if the smart antenna changed the beam width and orientation of the of the sectors by narrowing the A sector to cover a particularly dense traffic area and widened the beam width of B sector  512 , prior art geo-location systems attempting to locate mobile appliance  500  would assume the mobile is in the pre-assigned coverage area occupied by sector A  511 . Therefore the system would tasks sensors in sector  561  in base station  560  and sector  573  in base station  570  to locate the mobile. However, as before these are not the sectors closest in vicinity to the mobile and thus a poor location would be estimated. 
         [0025]    Additionally, the RF signals from the mobile must pass through the smart antenna array and the accompanying electronics. These entities add delay to the time of arrival of the RF when compared to the normal path delay that would be encountered at the base station without a smart antenna present and thus can lead to inaccurate location results when time-based location techniques such as TDOA are used. 
         [0026]    Therefore with the increased used of smart antennas for dynamically adjusting the coverage sectors, there is a need for a geo-location system which is capable of use with communication system which implement sector modifications with smart antenna. 
         [0027]    In view of this need, it is the object of the present disclosure to obviate the deficiencies in the prior art and present a method for determining a location of a target mobile appliance, in a wireless communication system with a network overlay geo-location system. The wireless system includes plural base stations and a MPC, each of the base stations include pre-assigned sectors defining a coverage area. One of the base stations includes a smart antenna. The method includes the steps of determining the serving sector from the pre-assigned sectors and using a database to determine if the serving sector&#39;s base station has a smart antenna. The method involves scanning antennas elements of the serving sector&#39;s base station, prior to pattern forming, for the target mobile appliance&#39;s signal to find the actual sector for the mobile appliance. The system then tasks sensors in proximity of the actual sector to locate the mobile appliance. 
         [0028]    It is also an object of the present disclosure to present a novel method for determining the location of a target wireless appliance in a network overlay geo-location system for wireless appliances operating in a host wireless communication system. The host system includes a several base stations including sectors defining a coverage area, and one of the base stations employs a smart antenna. The host system also includes a mobile positioning center which provides the geo-location system with information parameters to assist in the location acquisition of the wireless appliance. The method determines a sector of interest from the information parameters and tasks sensors near each sector of the sector of interest base station to locate the mobile appliance. 
         [0029]    It is another object of the present disclosure to present a novel method for determining the location of a mobile appliance independently of sector information provided by the MPC. The wireless communication system having a network overlay geo-location system including plural base stations and an MPC. The base stations having assigned channels for each sector representing a coverage area, and one or more of the base stations include smart antennas for adapting the sectors within the coverage area including reassignment of channels. The method entails tasking plural geo-location sensors in the geo-location system to search for the signal and selecting a set of sensors based on the mobile appliance&#39;s signal parameters at each sensor and locating the mobile appliance with the set of sensors. 
         [0030]    It is still another object of the present disclosure to present a novel improvement for a method of locating a mobile appliance operating in a wireless communication system with at least one base station employing a smart antenna. The method including receiving mobile information from a MPC, including information for determining an assigned sector, and tasking geo-location sensors proximate to a search area to locate the mobile appliance. The improvement includes for each antenna output associated with the assigned sector&#39;s base station, measuring a parameter of the mobile appliance&#39;s signal; and, selecting the search area based on the measured parameters. 
         [0031]    It is yet another object of the present disclosure to present a novel method for determining the location of a target wireless appliance from the target wireless appliance&#39;s signal parameters measured at plural geo-location sensors. The method including determining from a database which geo-location sensors are located at base stations with smart antennas; adjusting the measured parameters from geo-location sensors located at base stations with smart antenna; and, determining the location of the mobile appliance from the adjusted measured parameter. 
         [0032]    It is an additional object of the present disclosure to present a novel wireless communication system with a network overlay geo-location system having a plurality of sensors located at plural base stations. The system includes a base station with a smart antenna, the smart antenna having an antenna array and a pattern-forming network. The system also has a mobile positioning center in communicational connection with the network overlay geo-location system. The sensors of the network overlay geo-location system being connected to the smart antenna at an interface between the antenna array and the pattern-forming network. 
         [0033]    It is yet an additional object of the present disclosure to present an improved network overlay geo-location system in a wireless communication system with a host base station having a smart antenna. The smart antenna including an antenna array and a pattern-forming network and the sensors are connected to the smart antenna at an interface between the antenna array and the pattern forming network. 
         [0034]    It is still an additional object of the present disclosure to present a novel method for locating the mobile appliance. The method includes the steps of: retrieving serving sector information from the mobile position center, determining from a database if the serving sector is at a base station with a smart antenna and switching a network overlay geo-location system to a selected one of two different operating modes based on the determination. 
         [0035]    These objects and other advantages of the disclosed subject matter will be readily apparent to one skilled in the art to which the disclosure pertains from a perusal or the claims, the appended drawings, and the following detailed description of the preferred embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0036]      FIG. 1  is an illustration of a standard network overlay geo-location system with host wireless communication system. 
           [0037]      FIG. 2  is a representation of a typical base stations sectorized coverage area. 
           [0038]      FIGS. 3   a  and  3   b  is a representation of a sectorized coverage area of a base station utilizing a smart antenna. 
           [0039]      FIG. 4  is a representation of a smart antenna. 
           [0040]      FIG. 5   a  is a representation of cells in a communication system, illustrating the selection of proximate sectors. 
           [0041]      FIG. 5   b  is a representation of cells in a communication system with base stations using smart antennas switching channel assignments, illustrating the selection of proximate sectors. 
           [0042]      FIG. 5   c  is a representation of cells in communication system with base station using smart antennas changing sector beam width and orientation, illustrating the selection of proximate sectors. 
           [0043]      FIG. 6  is a representation of a network overlay geo-location system with host wireless communication system according to an embodiment of the disclosed subject matter. 
           [0044]      FIG. 7  is a representation of a network overlay geo-location system with host wireless communication system according to another embodiment of the disclosed subject matter. 
           [0045]      FIG. 8  is a flow chart of the operation of the geo-location system according to an embodiment of the disclosed subject matter. 
           [0046]      FIG. 9  is a representation of cells in a communication system locating a mobile according to the embodiment of  FIG. 8 . 
           [0047]      FIG. 10  is a flow chart of the operation of a geo-location system according to another embodiment of the disclosed subject matter. 
           [0048]      FIG. 11  is a representation of cells in a communication system locating a mobile appliance according to the embodiment of  FIG. 10 . 
           [0049]      FIG. 12  is a flow chart of the operation of a geo-location system according to yet another embodiment of the disclosed subject matter. 
           [0050]      FIG. 13  is a representation of cells in a communication system locating a mobile appliance according to the embodiment of  FIG. 12 . 
       
    
    
     DETAILED DESCRIPTION 
       [0051]    In order for a network overlay geolocation system to operate in a smart antenna-equipped base station/network, innovations over standard network overlay geolocation systems must be employed that do not rely solely upon the mobile information currently supplied by the mobile positioning center, or equivalent. 
         [0052]      FIG. 6  is an embodiment of a wireless communication system with a network overlay geo-location system that accounts for the sector and channel variations presented by the use of a smart antenna in locating a target mobile appliance. As in  FIG. 1 , the host wireless communication system includes a plurality of base stations  601 - 604  and a mobile switching center  45  ( FIG. 1 ). One of the base stations  601  in  FIG. 6  is shown with a smart antenna  610 . The smart antenna  610  contains the same features with the same reference numerals as described previously in  FIG. 4 . The network overlay geo-location system is formed by a central processing unit, GCS  650  and a plurality of sensors ( 621 - 624 ) located at the base stations. 
         [0053]    Normally connected to the mobile positioning center is a configuration database  640  which includes the wireless system configuration information, including channel assignment, sector size and sector orientation as originally configured or amended. The configuration database reflects the set parameters, not necessarily the current base station parameter. The configuration database  640  in the embodiment of  FIG. 6  also includes an extra field beyond the prior art. This additional field simply contains information designating which base stations within the communication system have or use smart antennas. This information regarding the presence of smart antennas at the base stations can alternatively be contained in a database accessible to the geo-location system located other than at the GCS, likewise in the embodiment shown, the database need not be contained in the GCS since only access is required. The system configuration database can also be augmented with a field to indicate which sensors are located at smart antennas, rather than which base stations have smart antennas. 
         [0054]    The information contained in the extra field can be used as a key reference for the geo-location system in determining the manner in which sensors are selected to locate the target mobile appliance. Specifically, this field can be used to select a mode of operation of the geo-location system. In one mode, where no smart antennas are present, the ordinary method of selecting sensors is implemented since the information provided by the MPC and which the selection is based are most likely valid. In another mode the geo-location system proceeds with the selection of neighboring sectors while recognizing the possible reallocation of the sector configuration enabled by the smart antennas and accounting for such possible changes. 
         [0055]    In base stations  601  the geo-location sensors  607  or wireless location sensors (WLS) are specifically connected to the smart antenna by an interface between the antenna array  401  of the smart antenna  610  and the pattern-forming network  410  with interface  608 . The location of the geo-location sensors  621  interface  608  to the smart antenna/base station equipment ensures its antenna feeds are not affected by the dynamic spatial patterns of the smart antenna  610 , while the embodiment shows a single WLS  621  and interface  608 , multiple sensors and interfaces are equally functional, for clarity, a composite sensor is shown. Interfaces that meet these criteria include after the antenna array  401 , or after the antenna array and fixed beam formers  615  or switches (not shown) in the RF chain in the smart antenna  610 . Both of these interfaces are before the dynamic beam/null/sector steering/switching apparatus (i.e. pattern-forming network  410 ) in the smart antenna  610 . In other words the output of the pattern-forming network of a smart antenna is indistinguishable in regards to channel assignment and other sector characteristics from the antenna output in conventional fixed channel fixed sector antennas, even though the sector characteristics may be entirely different. 
         [0056]    The embodiment shown in  FIG. 6  includes a fixed beam former  615  which is commonly used in standard base stations for several known reasons that will not be further expanded here. As stated above the fixed beam former  615  does not act to dynamically change or alter the sector/channel characteristics from that presumed in the system configuration database. 
         [0057]    The embodiment shown in  FIG. 7  also includes another database or database fields which include time adjustments for sensors attached to smart antennas. In smart antennas the additional time delay elements in the RF path between the antenna array  401  and the location sensor (WLS) exist due to the processing in the pattern forming network. In this embodiment the sensors are located in the receive path after the pattern-forming network. These time adjustments are stored in the auxiliary database  641  and are sensor specific. The time delay adjustments can be empirically or experimentally determined. In this way, the time delay for these elements can be compensated for in the time difference of arrival calculation. The key can also trigger the execution of other function at the sensors as described below. 
         [0058]    The sensor at the base stations with smart antennas can operate in a mode where the mobile appliance of interest is not located within the sector coverage area as indicated by the tasking parameters, but instead in the sector where it actually resides. As discussed previously the unique operation in the network overlay location equipment to accommodate this situation is necessary, so as to not rely on the serving sector information provided when a smart antenna is operating at the base station, but instead to rapidly scan all of the antenna outputs provided to the location system to find the antenna that best receives the mobile in question. Once the serving area is identified, then the sensors in the proximity of the actual mobile&#39;s position can be switched to the proper antenna elements, and tasked to provide time or angle data on the mobile to determine a position. 
         [0059]    To determine the antenna output that best receives the mobile, power level can be used. Existing radio assets and antenna switches in the sensors (WLS) can be used to perform the scanning function. 
         [0060]      FIG. 8  is a representative flow chart of the operation of the geo-location system for locating a mobile appliance in a wireless communication system employing smart antenna at one or more of its base stations. As shown is block  801  the MPC generates the mobile information, including the serving sector from information provided by the wireless network, and this information is relayed to the geo-location system. The geo-location system in block  802  accesses a database  803  which includes the extra field that indicates which sectors employ smart antennas. 
         [0061]    The geo-location system scans antenna elements of all the sectors in the serving sectors base station and may also scan antenna elements in neighboring base stations as shown in block  804 . A parameter, such as received signal strength, or a quality metric formed from a cross correlation of known features of the target mobile signal, such as a training sequence pattern, pilot signal or other known data, is estimated or measured for each of the antennas scan in block  805 . The geo-location system using the received signal strengths or other suitable signal parameter determines or selects the actual geographic sector serving the mobile appliance as indicated in Block  806  and determines sector sensors (WLS) in the vicinity of the actual serving sector in block  807  which are tasked to determine the time of arrival of the mobile appliances signal in block  808 . The geo-location system then locates the mobile appliances by the time-of-arrival at the selected sector sensors using time-difference-of-arrival or angle-of-arrival. Since the actual sector is determined and used to identify sensors in the vicinity, the accuracy of the information provided by the MPC will not affect the accuracy of the determined location. The mobile appliance&#39;s signal is typically a traffic channel, however, reverse pilot signals available in 3 rd  Generation CDMA systems can also be used in the geo-location system. 
         [0062]      FIG. 9  is a representation of the process used to address the situation presented in  FIG. 5   b . A smart antenna operating at base station  910  reassigns RF channel, z from sector C  913  to sector A  911  through an RF switch in the smart antenna to accommodate extra traffic seen on the A sector  911 . The MPC relays mobile information to the geo-location system, including information designating sector C  913  as the serving sectors. The geo-location system accesses a database, or a field in the system configuration database indicating the serving sector C  913  is at a base station with a smart antenna. The geo-location system scans all the antenna elements of sectors  911 ,  912  and  913  and measures the received signal strength of the mobile signal. The measurements indicate the strongest signal from an antenna element located in the A sector  911  and thus tasks the sensors (WLS) in sectors proximate to the actual sector A  911 , namely the sensor at sector  932  of base station  930  and sector  923  of base station  920  to record the time of arrival of the mobiles signal. Of course, as stated previously, other sensors in the vicinity of the actual sector can also be tasked to locate the mobile appliance, however are not shown for clarity. The geo-location system then uses these times of arrival to calculate time difference of arrival, angle of arrival or other known means to locate the mobile appliance. The results of the described method, when compared with that shown in  FIG. 5B  is clearly advantageous. The similarly advantageous sensor selection and geo-location would result if the operation was applied to the example demonstrated in  FIG. 5   c.    
         [0063]      FIG. 10  is a representative flow chart of an embodiment of the disclosed subject matter. As in the embodiment above, in block  1001  the MPC provides mobile information including a sector of interest for the targeted mobile appliance. At the geo-location system, the database or database field  1003  is accessed to determine whether the sector of interest&#39;s base station uses a smart antenna in block  1002 . In block  1004 , the geo-location system selects sector sensors proximate to all of the sectors associated with the sector of interest&#39;s base station. The geo-location system then uses the time of arrival at the selected sector sensors to determine the location of the mobile appliance using TDOA or AOA or other known methods. 
         [0064]      FIG. 11  shows the selection of sector sensors in neighboring base stations for the method shown in  FIG. 10 .  FIG. 11  duplicates the smart antenna scenario described with respect to  FIG. 5   b  and  FIG. 9  previously. Using the embodiment of  FIG. 10 , the geo-location system upon identifying sector  1111  as the sector of interest for mobile appliance  1100  tasks all the sector sensors proximate to each sector (A, B and C) of the sector or interest&#39;s base station  1110  to locate the mobile appliances signal. As shown, sensors located in sectors  1123 ,  1132 ,  1142 ,  1151 ,  1161 , and  1173  of base stations  1120 ,  1130 ,  1140 ,  1150 ,  1160  and  1170  respectively are used to locate the mobile stations. Without this type of tasking, resource utilization in a standard geo-location system could be excessive for a wireless communication system using smart antennas at the base stations. Further, such an approach allows improved location performance when the serving sector or sector of interest provided by the MPC is different from the actual sector. 
         [0065]      FIG. 12  is a flow chart of another embodiment of the disclosed subject manner. As shown in block  1201 , the geo-location system tasks sensors at more than one base stations in the communication system to search for the mobiles signals The tasked sensors measure received signal strength of the mobile signal, block  1202 , and the geo-location system selects a set of the sensors in block  1203  to locate the mobile based on the measured received strength of the signal. In this manner, the actual sector of the mobile appliance is not needed. The sensors selected to locate the mobile are selected on the basis of their actual ability to receive the signal, therefore their vicinity is irrelevant. The geo-location system uses TDOA, and/or AOA of the signal at the selected sensors to locate the mobile.  FIG. 13  shows a representation of the operation of the location system for  FIG. 12  in the scenario presented in  FIG. 5   b.    
         [0066]    As shown in  FIG. 13 , each of the sectors searches for the signal. Sectors  1332 ,  1342 ,  1361  and  1373  received the signal at a sufficient high signal strength and thus are identified and participate in the determination of a location of the mobile. Under other operations as shown in  FIG. 9 , sector  1323  would normally also be selected, however, because of other factors such as geography, or antenna height or localized interferers, the signal was not received with a high signal strength. Nonetheless, the geo-location system, since it does not rely on the sector information from the MPC, was able to locate the mobile. 
         [0067]    While preferred embodiments of the present inventive system and method have been described, it is to be understood that the embodiments described are illustrative only and that the scope of the embodiments of the present inventive system and method is to be defined solely by the appended claims when accorded a full range of equivalence, many variations and modifications naturally occurring to those of skill in the art from a perusal hereof