Abstract:
When a wireless terminal enters a new location, the telephone number assigned to the wireless terminal is automatically changed to a telephone number assigned to that location based on an assignment level of the wireless terminal for that location. The features associated with the wireless terminal will also be changed to the features assigned to the location. In addition, this invention allows flexibility for the telephone number of the wireless terminal to remain fixed and not to be changed to a telephone number assigned to a particular location. Further, a wireless terminal has a plurality of assignment levels with different assignment levels being utilized for different locations. This allows the user of the wireless terminal to perform different functions within different locations. In addition, each wireless terminal has a personal telephone number assigned to it. The wireless telephone can use either its personal telephone number or the telephone number of the present location for purposes of caller identification during call originations.

Description:
TECHNICAL FIELD 
     This invention relates generally to wireless switching systems and, in particular, to the assignment of telephone numbers. 
     BACKGROUND OF THE INVENTION 
     In the modern business environment of today, individuals have different responsibilities and work in different job locations that change on an hourly basis or a daily basis. For example, an individual may be a secretary working at a particular desk for part of the day and a librarian working in a corporate library for the remainder of the day. In addition, within a department store, an individual may work in the shoe department for part of the day and work in the household department for the remainder of the day. At present, each of these departments has wired telephones which are permanently stationed in each of the areas where an individual may go to work. Department stores and many other businesses publish to their customers and clients the internal telephone number that may be dialed by an outside individual to reach a particular department. For example, a customer of a department store wishing to call the houseware department simply dials the direct number for that department. 
     With the advent of wireless telephones, companies have been forced to dedicate wireless telephones for each particular department having the telephone number assigned to that department. This presents many problems for companies. For example, a common problem is for an employee, after their shift is completed, to leave the department still carrying the wireless telephone; hence, the dedicated wireless telephone cannot be utilized by another employee coming on for the next shift. In addition, it is hard to determine precisely how many dedicated wireless telephones are needed for each particular department. Furthermore, if an employee comes into a particular department to lend temporary assistance for a matter of minutes, they must try to find a dedicated wireless telephone assigned to that department. In addition, within a particular department, individual employees may have different skill levels within that department which are different than another department. In addition, an employee may be the supervisor of one department but go to another department and be a mere worker. Such a transition would occur if the second department was in drastic need of assistance. To properly direct calls, the wireless switching system needs to take into account the skill level or managerial level of employees as they enter or leave various departments. 
     SUMMARY OF THE INVENTION 
     This invention is directed to solving these and other problems and disadvantages of the prior art. According to the invention, when a wireless terminal enters a new location, the telephone number assigned to the wireless terminal is automatically changed to a telephone number assigned to that location based on an assignment level of the wireless terminal for that location. Advantageously, the features associated with the wireless terminal will also be changed to the features assigned to the location. In addition, this invention allows flexibility for the telephone number of the wireless terminal to remain fixed and not to be changed to a telephone number assigned to a particular location. Advantageously, a wireless terminal has a plurality of assignment levels with different assignment levels being utilized for different locations. This allows the user of the wireless terminal to perform different functions within different locations. In addition, each wireless terminal has a personal telephone number assigned to it. The wireless telephone can use either its personal telephone number or the telephone number of the present location for purposes of caller identification during call originations. 
     These and other features and advantages of the present invention will become more apparent from the following description of an illustrative embodiment of the invention considered together with the drawing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a block diagram of a wireless system for implementing the invention; 
     FIGS. 2 and 4 illustrate a table that is maintained by a wireless switching system defining the relationship between the physical identification number of a wireless terminal and its assigned telephone number; 
     FIG. 3 illustrates a table that defines the telephone numbers assigned to each location; 
     FIGS. 5 and 6 illustrate, in flow chart form, steps performed by a wireless switching system; 
     FIG. 7 illustrates, in block diagram form, a fixed unit; 
     FIG. 8 illustrates, in block diagram form, a wireless terminal; 
     FIG. 9 illustrates, in flow chart form, steps performed by a wireless terminal; 
     FIG. 10 illustrates, in flow chart form, steps performed by a fixed unit; and 
     FIGS. 11-13 illustrate a table maintained by a wireless switching system for each wireless terminal. 
    
    
     DETAILED DESCRIPTION 
     In FIG. 1, switching system  111  provides wireless service for wireless terminals  112 - 114  via base stations  121 - 122 . Wireless switching system  111  is interconnected to public telephone network  118  via link  117 . Wireless switching system  111  determines the location of a wireless terminal in the following manner. The location is designated with the same number as the fixed unit identifying that location. For example, fixed unit  101  provides the location information for location  101 . A fixed unit transmits a signal at predefined intervals defining the identity of the fixed unit. This transmission occurs on a different transmission medium than that utilized by the wireless terminals to communicate with the base stations. For example, when wireless terminal  112  enters location  103 , it receives the identification information defining fixed unit  103 . Upon receiving identification information defining a new fixed unit, wireless terminal  112  transmits a data message to wireless switching system  111  and inform wireless switching system  111  that wireless terminal  112  is now receiving the identification information from fixed unit  103 . Wireless switching system  111  then identifies that wireless terminal  112  is in location  103 . One skilled in the art could readily see that other methods could be utilized to determine the location of a wireless terminal. For example, the wireless terminals could transmit identification information defining the wireless terminal to a fixed unit which then could relay this to wireless switching system  111  via wired or wireless media to wireless switching system  111 . In addition, global positioning satellite (GPS) devices or base stations could be used to determine a position of a wireless terminal. 
     In accordance with the invention, when wireless switching system  111  receives information from wireless terminal  112  that it is in location  103 , wireless switching system accesses Table 3 of FIG. 11 to determine what the assigned level number for wireless terminal  112  in location  101 . From Table 3, wireless switching system  111  determines that the assigned number is a “1”. Wireless switching system  111  then accesses Table 2 of FIG. 3 at Level  1  to obtain the telephone number for location  101  which in this example will be 538-3901. Wireless switching system  111  updates Table 2 of FIG. 3 as is illustrated in FIG.  3 . Wireless switching system  111  then updates Table 1 to reflect that wireless terminal  112  is at location  103  and has the telephone number of  538 - 3901 . If in Table 3 of FIG. 11, location  103  would have had an assignment level number of  3 , wireless switching system  111  would have accessed Level  3  and obtained a telephone number of 538-2922 for wireless terminal  111 . In addition, the Table 2 of FIG. 3 is updated to reflect that telephone number is assigned to wireless terminal  112 . Both Tables 1-3 refer to the wireless terminals by designation numbers as illustrated in FIG. 1 for convenience of description. In actual implementation, the serial numbers of wireless terminals would be used instead of the designation numbers. A wireless terminal has a 12 digit serial number that is used to identify the wireless terminal to wireless switching system  111 . The serial number is transmitted with each message to wireless switching system  111 . 
     Consider now the example, where wireless terminal  112  moves from location  103  to location  104  via location  101 . When wireless switching system  111  is informed by wireless terminal  112  that it is now in location  101 , wireless switching system  111  determines from FIG. 2 that the assigned telephone number for wireless terminal  112  is not to be modified when the wireless terminal enters location  101 . Consequently, wireless switching system  111  does not modify the current telephone number illustrated in Table 1 of FIG. 2 for wireless terminal  112 . Further, consider when the wireless terminal moves to location  104 . Upon being informed that wireless terminal  112  has entered location  104 , wireless switching system  111  examines Table 3 of FIG.  11  and determines that the assigned level for wireless terminal  112  in location  104  is a “2”. Based on this information, wireless switching  111  accesses Level  2  and determines that wireless terminal  112  should be assigned telephone number 538-1911. Hence, wireless switching system  111  assigns telephone number 538-1911 to wireless terminal  112 . Table 1 of FIG. 2 is updated to reflect this change and the updated table is illustrated in FIG.  4 . In addition, Table 2 of FIG. 3 would be updated to reflect the fact that wireless terminal  112  is now assigned telephone number 538-1911. If wireless terminal  114  had not been present in location  104  when wireless terminal  112  entered location  104  and Table 3 of FIG. 11 contained a “1” for location  104 , wireless terminal  112  would have been assigned telephone number 538-1901. Table 2 of FIG. 3 will also be updated to reflect the fact that telephone number 538-3901 is no longer assigned to wireless terminal  112 . 
     Since wireless terminal  112  has been assigned a new telephone number the features associated with that telephone number now are provided to wireless terminal  112  by wireless switching system  111 . When a call is received from public telephone network  118  for telephone number 538-1902, wireless switching system  111  examines Table 1 of FIG.  4  and determines that the call should be routed to wireless terminal  112 . One skilled in the art would readily recognize that the telephone numbers illustrated for each individual location in Table 2 could be placed in a hunt group by wireless switching system  111 . Such a hunt group would allow a telephone call directed to a first number for a location to subsequently be transferred to a second number of the location if the first number of the location was busy. 
     FIGS. 5 and 6 illustrate, in flowchart form, the steps performed by wireless switching system  111  in implementing the invention. Decision block  501  determines if there is a message from a wireless handset. If the answer is no, control is transferred to block  502  which performs normal processing before returning control back to decision block  501 . If the answer in decision block  501  is yes, decision block  505  determines if a call origination is being performed by the wireless telephone. If the answer is yes, control is transferred to decision block  1401  of FIG.  14 . If the answer is no, control is transferred to decision block  507 . Decision block  507  determines if a “no fixed unit” message is being received from a wireless telephone. Such a message indicates that a wireless telephone is not receiving the transmission signal from any fixed unit. If the answer is yes in decision block  507 , control is transferred to block  504  which determines the last known location. Wireless switching system  111  maintains a list of last known locations for each of the wireless terminals. Block  506  then signals that the wireless telephone cannot receive a fixed unit around the last location listed for the wireless telephone. This signaling may be in the form of a message displayed to an operator of wireless switching system  111  or merely a message being included in a maintenance log of wireless switching system  111 . After execution of block  506 , control is transferred back to decision block  501 . 
     Returning to decision block  507 , if the answer is no, decision block  508  determines if a low battery indication was included in the message identifying the fixed unit from the wireless telephone. If the answer is no in decision block  508 , block  509  determines the location based on the identification code of the fixed unit of the wireless telephone before transferring control to decision block  601  of FIG.  6 . If the answer in decision block  508  is yes, the low battery indication for the identified fixed unit is placed in the database, and a maintenance message indicating low battery is generated before transferring control to block  512 . Block  512  performs the same operations as block  509  before transferring control to decision block  601  of FIG.  6 . 
     After the determination of the location of a wireless terminal has been made in either block  509  or  512 , control is transferred to decision block  601  of FIG.  6 . The latter decision block determines if the location of the wireless terminal has changed by examining Table 1 of FIGS. 2 or  4 . If the answer is no, control is transferred back to decision block  501  of FIG.  5 . If the answer in decision block  601  is yes, control is transferred to decision block  602  which examines Table 1 of FIGS. 2 or  4  to determine if the new location is excluded for the wireless terminal. If the answer is yes, control is transferred back to decision block  501  of FIG.  5 . In the previous example, when wireless terminal  112  entered location  101 , decision block  602  would have determined from FIG. 2 that location  101  was excluded for wireless terminal  112 . 
     If the answer is no in decision block  602 , control is transferred to decision block  603 . The latter decision block examines Table 2 of FIG. 3 to determine if there are any idle telephone numbers associated with the new location. If there are no idle telephone numbers associated with the new location the wireless terminal&#39;s telephone number cannot be changed and remains the same as for the previous location. Note, that the present location in Table 1 of FIG. 2 is not updated to reflect the new location and remains set to the old location. The next time that the wireless terminal transmits its location, decision block  601  once again detects a change in location and once again control is transferred to decision block  603  to see if there is now a idle telephone number in Table 2 for the new location. If the answer in decision block  603  is no, control is transferred back to decision block  501  of FIG.  1 . If the answer in decision block  603  is yes, control is transferred to block  606  which accesses Table 3 and determines the assigned level number for the new location before transferring control to block  604 . The latter block then uses the assigned level number and the location information to access the appropriate level of Table 2 of FIG.  3 . Block  604  then determines what the assigned telephone number should be in that Table 2. Block  604  also updates Table 2 to reflect the new telephone number that is assigned to the wireless terminal and to remove the indication that the old telephone number is assigned to the wireless terminal. After execution of block  604 , control is transferred to block  605  which updates Table 1 for the assigned telephone number for the wireless terminal and to indicate the present location as the new location. After execution of block  605 , control is transferred back to decision block  501  of FIG.  5 . 
     Returning to decision block  505  of FIG. 5, if the answer is yes, control is transferred to decision block  1401  of FIG.  14 . Decision block  1401  determines if the personal telephone number of the wireless terminal is to be utilized or the location telephone number of the wireless terminal&#39;s present location is to be used for the caller identification information during a call origination. If the personal telephone number is to be utilized, the call is completed by block  1402 . If the location telephone number is to be utilized, the call is completed by block  1403 . After execution of either block  1402  or  1403 , control is transferred back to decision block  501  of FIG.  5 . 
     FIG. 7 illustrates in block diagram form a fixed unit. The fixed unit of FIG. 7 is powered by battery  701 . However, one skilled in the art could readily see that normal building AC power could also be utilized to power the fixed unit. Controller  703  periodically transmits the identification code for the fixed unit via transmitter  704 . Advantageously, transmitter  704  can be transmitting utilizing infrared transmission or ultrasonic transmission. Transmitters for transmitting either infrared or ultrasonic are well known in the art. If controller  703  detects that battery  701  is at a low power level via conductor  707 , battery monitor  702 , and conductor  708 , controller  703  sets alarm indicator  705  and transmits the low power indication along with the identification code via transmitter  704 . 
     Wireless handset  112  is illustrated in greater detail in FIG.  8 . Wireless handset  112  implements a wireless protocol that allows wireless handset  112  to transmit data messages to wireless switching system  111  via base stations  121 - 122 . One air interface that can be used is the Common Air Interface (CAI) specification for Cordless Telephony 2 (CT2), Release 2, I-ETS 300 131. The data message is a layer  3  message. Particularly, the data message is transported as a feature activation class 3 of the TERMCAP IE using a new value. Overall control of the wireless handset is provided by control unit  801 . Units  802 ,  803 ,  806 ,  807 ,  808 , and  809  provide the RF communication capabilities for the wireless handset. Elements  804 ,  810 , and  811 - 814  provide the audio information received and transmitted to the user; whereas, elements  816 - 818  and  805  provide the basic user interface. The CT2 protocol allows control unit  801  to transmit data messages to wireless switching system  111 . Control unit  801  utilizes these data messages to transmit identification information for fixed units to wireless switching system  111 . Fixed unit receiver  321  receives the identification code of a fixed unit and transfers this identification code to control unit  801  for transmission to wireless switching system  111 . Fixed unit receiver  321  is of a design well known in the art for either infrared or ultrasonic transmission media. One skilled in the art could readily see that fixed unit receiver  321  could provide to control unit  801  the signal strength of the received signal. Further, control unit  801  could also tune fixed unit receiver  321  to receive different frequencies or other variations of the transmission media using well known techniques in the art. 
     FIG. 9 illustrates the steps performed by a wireless terminal such as wireless handset  113 . Decision block  901  determines if the time has elapsed to monitor for a fixed unit. Advantageously, every second the wireless handset monitors to determine if the transmission signal of a fixed unit is being received. If the answer in decision block  901  is no, normal processing is performed by block  902  before control is returned back to decision block  901 . 
     If the answer in decision block  901  is yes, control is transferred to decision block  903  which determines if a transmission signal is being detected. If the answer in decision block  903  is no, control is transferred to block  906 . The wireless handset transmits a “no fixed unit” message to the central computer by execution of block  906  before transferring control back to decision block  901 . Returning to decision block  903 , if the answer is yes, control is transferred to block  909 . The latter block determines the identification code of the fixed unit whose transmission signal is being received, and block  911  transmits the received identification code to wireless switching system  111  before transferring control to decision block  912 . Decision block  912  determines if a low battery indication was included in the transmission signal from the fixed unit. If the answer is no, control is transferred back to decision block  901 . If the answer in decision block  912  is yes, block  913  transmits a low battery indication message to wireless switching system  111  for the identified fixed unit. 
     FIG. 10 illustrates the steps performed by a fixed unit. Decision block  1001  determines if it is time to transmit the identification code of the fixed unit. Advantageously, the identification code is transmitted every tenth of a second. If the answer is no, control is transferred back to decision block  1001 . If the answer is yes, decision block  1003  determines if battery monitor  702  of FIG. 7 is indicating a low battery. If the answer is no, block  1004  simply transmits the identification code of the fixed unit before transferring control back to decision block  1001 . If the answer in decision block  1003  is yes, block  1006  transmits a message that includes the identification code and a low battery indication before transferring control back to decision block  1001 . 
     Of course, various changes and modifications to the illustrative embodiment described above will be apparent to those skilled in the art. These changes and modifications can be made without departing from the spirit and the scope of the invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be covered by the following claims.