Abstract:
A wireless terminal is dynamically placed into a call coverage group based on the location of the wireless terminal. Similarly, a wireless terminal is dynamically removed from a call coverage group on the basis of the location of the wireless terminal. In addition, within a call coverage group, the position of a wireless terminal that is in communication with an auxiliary desktop unit is determined by a preassigned position within the call coverage group of the auxiliary desktop unit. The wireless terminal in communication with the auxiliary desktop unit is always assigned this preassigned location in the call coverage group. Other call coverage groups that are based on geographical location and where the wireless terminal is not communication with an auxiliary desktop unit have wireless terminals assigned into the call coverage path group based on a predefined algorithm.

Description:
TECHNICAL FIELD 
     This invention relates to wireless telecommunication terminals, and, in particular, to the provision of call coverage paths. 
     BACKGROUND OF THE INVENTION 
     In prior art business telecommunications switching systems, call coverage groups are well known. A call coverage group allows a list of telephones to be stored within the switching system to handle calls for a telephone of a principal. When the switching system receives a call for the principal&#39;s telephone and the principal&#39;s telephone does not answer, the switching system attempts to connect the calling party with the first telephone in the call coverage telephone group. If the first telephone is unavailable, then the second telephone in the call coverage group is selected. In the prior art, the call coverage groups are administered manually. 
     The prior art call coverage groups have functioned well with wired telephone sets and wireless telephones where the wireless telephone was a second telephone set for a user. In addition, prior art call coverage groups and their administration have functioned well for the traditional business environments where an employee is assigned a desk or a specific location and performs their principal work function at that telephone or location. For example, the traditional environment is for a principal to have a telephone and for the first telephone in the call coverage path of the principal&#39;s telephone to be the principal&#39;s secretary. The traditional environment is slowly changing. In the emerging business environment, individuals do not have a wired telephone but rather they have a wireless telephone which they carry with them at all times and which is their only telephone set. In addition, employees during the course of a day perform many functions at different locations. For example, a principal&#39;s secretary may vary with the time of day. 
     SUMMARY OF THE INVENTION 
     The foregoing problems are solved, and a technical advance is achieved by an apparatus and method in which a wireless terminal is dynamically placed into a call coverage group based on the location of the wireless terminal. Similarly, a wireless terminal is dynamically removed from a call coverage group on the basis of the location of the wireless terminal. In addition, within a call coverage group, the position of a wireless terminal that is in communication with an auxiliary desktop unit is determined by a preassigned position within the call coverage group of the auxiliary desktop unit. The wireless terminal in communication with the auxiliary desktop unit is always assigned this preassigned location in the call coverage group. Advantageously, other call coverage groups that are based on geographical location and where the wireless terminal is not communication with an auxiliary desktop unit have wireless terminals assigned into the call coverage path group based on a predefined algorithm. 
     Other and further aspects of the present invention will become apparent during the course of the following description and by reference to the accompanying drawing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a conceptual view of a wireless terminal inserted into an auxiliary desktop unit for use with the invention; 
     FIG. 2 illustrates, in block diagram form, a system in accordance with the invention; 
     FIG. 3 illustrates, in block diagram form, the interconnection of the wireless terminal to a wireless telecommunication switching system and also to an auxiliary desktop unit; 
     FIG. 4 illustrates, in block diagram form, a wireless terminal; 
     FIGS. 5 and 6 illustrate, in flow chart form, steps performed by a wireless terminal; 
     FIG. 7 illustrates, in flow chart form, steps performed by an auxiliary desktop unit; 
     FIGS. 8 and 9 illustrate, in flow chart form, steps performed by a wireless switching system; and 
     FIGS. 10-15 illustrate tables used by a wireless switching system. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 illustrates wireless terminal  101  inserted into auxiliary desktop unit  102 . All voice, data, and control information communicated between wireless terminal  101  and auxiliary desktop unit  102  is communicated by wireless terminal  101  to a wireless telecommunication switching system not illustrated in FIG.  1 . Data and control information is communicated between wireless terminal  101  and auxiliary desktop unit  102  by infra-red receiver/transmitter  109  in wireless terminal  101  and infra-red receiver/transmitter  108  in auxiliary desktop unit  102 . Auxiliary desktop unit  102  provides standard programmable buttons and indicators  104  that are programmable to provide different telephone features and speed dialing. The functions performed between wireless terminal  101  with auxiliary desktop unit  102  can also be performed by wireless terminal  204 - 209 . 
     The manner in which wireless terminal  101  and auxiliary desktop unit  102  are utilized in the present invention is illustrated in FIG.  2 . FIG. 2 illustrates an office environment comprising cubicle areas  213  and  214 , principal&#39;s office  211  and secretarial office  212 . Telephone service for the office environment illustrated in FIG. 2 is provided by wireless terminals  203 - 209 , wireless terminal  101 , base stations  221 - 222  and wireless switching system  201 . Wireless terminal  203  is provided for the principal. The call coverage path group for wireless terminal  203  is as follows, the wireless terminal associated with auxiliary unit  102  and wireless terminal  207 , wireless terminal  208 , and wireless terminal  209 . As presently shown in FIG. 2, wireless terminal  101  is in communication with auxiliary unit  102 , wireless switching system  201  places wireless terminal  101  as the first wireless terminal that calls to which for wireless terminal  203  will be directed. However, if wireless terminal  101  leaves a secretarial office  212  and enters cubicle area  213 , wireless switching system  201  removes wireless terminal  101  from the call coverage group for wireless terminal  203 . Similarly, if wireless terminal  206  enters secretarial office  212  and establishes communication with auxiliary unit  102 , then, wireless terminal  206  is placed into the call coverage group for wireless terminal  203  as the first wireless terminal in that call coverage group. 
     Wireless switching system  201  is informed of which wireless terminal is in communication with auxiliary unit  102  in the following manner. Auxiliary unit  102  is periodically transmitting its identification code via the infrared medium. When wireless terminal  101  enters secretarial office  212 , it receives the infrared transmission and establishes a data call to wireless switching system  201 . Wireless terminal  101  then transmits a message defining that the wireless terminal is in communication with auxiliary unit  102  to wireless switching system  201 . Similarly, when wireless terminal  101  left secretarial office  212 , wireless terminal  101  detected the loss of the infrared link and transmitted a message to wireless switching system  201  that the wireless terminal was no longer in communication with auxiliary unit  102 . In the previous example, when wireless terminal  101  entered cubicle area  213 , wireless terminal  101  received an infrared transmission from fixed unit  215 . Wireless terminal  101  transmitted the identification of fixed unit  215  to wireless switching system  201  via the wireless data link. 
     Alternatively, one skilled in the art could readily envision that the auxiliary unit  102 , fixed unit  215  and fixed unit  216  could be connected to wireless switching system  201  via either wired or wireless connections. Further, the wireless terminals would transmit the identification of the wireless terminal to the fixed unit via an infrared medium or another medium. The fixed units and auxiliary unit  102  would then transmit the identifications of the wireless terminals to wireless switching system  201 . In addition, global positioning satellite (GPS) devices or base stations could be used to determine a position of a wireless terminal. 
     Wireless switching system  201  provides another type of call coverage group in accordance with the invention. The wireless terminals in cubicle area  213  form an area call coverage group. This call coverage group is maintained as a sequential list. When a new wireless terminal enters cubicle area  213 , wireless switching system  201  detects this via the wireless terminal reporting the identification of fixed unit  215 . Wireless switching system  201  adds the new terminal at the end of the call coverage group. In the present example, when wireless terminal  101  entered cubicle area  213  it was placed at the end of the area call coverage group. If wireless terminal  205 , which is part of the area call coverage group for cubicle area  213 , leaves cubicle area  213 , then, wireless terminal  205  is completely removed from the area call coverage group. There remains no reference to wireless terminal  205  in the area call coverage group for cubicle area  213 . 
     FIG. 3 illustrates a block diagram illustrating the interconnection between wireless telecommunication switching system  201 , wireless terminal  101 , and auxiliary desktop unit  102 . Auxiliary desktop unit  102  is shown in greater detail in FIG.  3 . Wireless terminal  101  is shown in greater detail in FIG.  4 . Wireless terminal  101  performs all the call control and high level processing of messages from wireless telecommunication switching system  201 . Communication of information between wireless terminal  101  and auxiliary desktop unit  102  is via infra-red transceivers  108  and  109 . One skilled in the art could readily envision other types of wireless links. Wireless terminal  101  maintains a control channel, a voice channel, and a data channel with auxiliary desktop unit  102  via the infra-red link. The protocol used on the infra-red link can be any number of well known protocols. Within auxiliary desktop unit  102 , interface  303  disassembles and assembles information being communicated on the infra-red link set up between transceivers  108  and  109 . The voice information is routed to or from voice code  302  for use either by speakerphone  106  or a headset plugged into headset jack  111 . Data information is routed to or from a data device connected on data jack  103 . When the infra-red link is first established, processor  304  transmits the identification code for auxiliary desktop unit  102  to wireless terminal  101  which transmits the identification code to wireless switching system  201 . Control information is communicated by interface  303  with processor  304 . The control information is utilized by processor  304  to control the operations of display  112  and the indicators on subunit  104 . Actuation of a programmable button causes processor  304  to transmit control information via interface  303 , transceiver  108 , and transceiver  109 , to wireless terminal  101 . Wireless terminal  101  is responsive to this control information to form a high level PHS wireless message that specifies which programmable button has been actuated. Similarly, wireless telecommunication switching system  201  transmits control information to wireless terminal  101  specifying which indicator on auxiliary desktop unit  102  is to be turned on via a high level PHS wireless message. Wireless terminal  101  decodes the PHS wireless message from wireless telecommunication switching system  201  and sends a message via the control channel of the infra-red link to processor  304  specifying that the indicator is to be lit. Wireless telecommunication switching system  201  processes the control information from auxiliary desktop unit  102  to provide features and other telephony operations using techniques well understood by those skilled in the art. 
     Wireless handset  101  is illustrated in greater detail in FIG.  4 . Wireless handset  101  implements a wireless protocol that allows wireless handset  101  to maintain a wireless signal link with wireless telecommunication switching system  201  via base stations included in wireless telecommunication switching system  201 . One air interface that can be used is the Japanese PHS protocol as set forth in “User-Network Interface and Inter-Network Interface Standards for PHS”, the Telecommunication Technology Committee, 1995, and “Personal Handy Phone System RCR Standard”, Version 1, RCR STD-28, Dec. 20, 1993. The message set of the PHS protocol is similar to the ISDN message set. Overall control of the wireless handset is provided by control unit  401 . Units  402 ,  403 ,  406 ,  407 ,  408 , and  409  provide the RF communication capabilities for the wireless handset. Elements  404 ,  410 , and  411 - 414  provide the audio information received and transmitted to the user; whereas, elements  416 - 418  and  405  provide the basic user interface. 
     The data and voice information is transmitted or received directly from RF transceiver  406  by control unit  401  and is communicated with auxiliary desktop unit  102  via transceiver  109 . One skilled in the art could readily see that this information could be directly received by transceiver  109  from RF transceiver  406 . Transceiver  109  would then form this information into the two data channels assigned to communication of voice and data information on the infra-red link. Note, that in the PHS protocol, control unit  401  would have to request one or more bearer channels to provide a channel for the data information that was being communicated with wireless telecommunication switching system  201 . It is well known by one skilled in the art how these additional bearer channels are obtained in the PHS protocol. 
     Control unit  401  is responsive to control messages received from wireless telecommunication switching system  201  to extract the INFO elements that define what indicators are to be controlled and the information to be displayed on display  112 . Control unit  401  then communicates this information to processor  304  via the infra-red link. Similarly, control unit  401  is responsive to messages from processor  304  defining button actuations on auxiliary desktop unit  102  to encode this information into INFO elements of PHS messages and to transmit those messages to wireless telecommunication switching system  201 . In addition, control unit  401  continuously monitors whether or not it is in communication with processor  304 . If control unit  401  is in communication with processor  304 , it sends control information for the indicators and display received from wireless telecommunication switching system  201  to processor  304 . In addition, control unit  401  continuously stores the status of the display and indicators of auxiliary desktop unit  102 . If control unit  401  is not in communication with processor  304 , it transmits this fact to wireless switching system  201 . FIGS. 5 and 6 illustrate the steps performed by a wireless terminal. Decision block  500  determines if the wireless terminal is in fixed contact with the auxiliary desktop unit. Fixed contact means that contact via the infra-red link had been established as detected by decision block  607  of FIG. 6, and the link is still active. If the answer in decision block  500  is yes, control is transferred to decision block  511  which determines if the initial contact flag was set in block  608  of FIG.  6 . If the answer is no, control is transferred to decision block  501 . If the answer is yes, the initial contact flag is reset, and the identification code of the auxiliary desktop unit is transmitted to the wireless switching system in block  512 . After execution of block  512 , control is transferred to decision block  501  which determines if there is a message from the wireless telecommunication switching system. If the answer is yes, decision block  502  determines whether this message contains data that is only intended to control some function on the auxiliary desktop unit. Such data would be contained within a INFO element. If the answer in decision block  502  is yes, the data contained in the INFO element is transmitted to the auxiliary desktop unit by block  506  before returning control to decision block  500 . If the answer in decision block  502  is no, any data destined for the auxiliary desktop unit is transmitted to the auxiliary desktop unit by block  503 . Block  504  then performs normal processing of control and data intended for utilization by the wireless terminal before returning control to decision block  500 . 
     Returning to decision block  501 , if the answer is no, decision block  507  determines if there is a message from the auxiliary desktop unit. If the answer is no, block  508  performs normal processing before returning control to decision block  500 . If the answer in decision block  507  is yes, the information in the message from auxiliary desktop unit  509  is formed into INFO elements of a message which is sent to the wireless telecommunication switching system before returning control to decision block  500 . 
     Returning to decision block  500 , if the wireless terminal is not in fixed contact with the auxiliary desktop unit, control is transferred to decision block  601  of FIG.  6 . Decision block  601  determines if there is a message from the wireless telecommunication switching system indicating initial contact with an auxiliary unit. If the answer is no, decision block  602  determines if a message from a fixed unit has been received. A message from the fixed unit would include the identification code of the fixed unit. If the answer is yes in decision block  602 , block  603  transmits the identification code of the fixed unit to the wireless switching system before transferring control to block  607 . If the answer in decision block  602  is no, control is transferred to block  604 . Block  604  transmits a message to the wireless switching system stating that there is no contact with either a fixed unit or an auxiliary unit before transferring control to decision block  607 . 
     After execution of block  604 , control is transferred to decision block  607  which determines if initial contact has been established with the auxiliary desktop unit. If the answer is yes, block  608  marks the fact that fixed contact has now been established with the auxiliary desktop unit and sets the initial contact flag. Block  609  stores the identification code of the auxiliary desktop unit for later transmission to the wireless switching system by  512  of FIG.  5 . After execution of block  609 , control is transferred to decision block  500  of FIG.  5 . If the answer in decision block  607  is no, block  611  marks that non-fixed contact is present with respect to the auxiliary desktop unit before transferring control to decision block  500  of FIG.  5 . Returning to decision block  601 , if the answer in decision block  601  is yes, control is transferred to decision block  607 . 
     Decision block  607  determines if contact with an auxiliary unit had been detected by decision block  601 . If the answer is no, block  611  marks non-fixed contact before returning control back to decision block  500  of FIG.  5 . If the answer is yes in decision block  607 , block  608  marks fixed contact. Then, block  609  stores the auxiliary unit identification information before transferring control back to decision block  500  of FIG.  5 . 
     FIG. 7 illustrates the steps performed by processor  304  of auxiliary desktop unit  102 . Decision block  700  determines if communication is established with a wireless terminal. If the answer is no, block  706  transmits the identification code on the infrared link before returning control to decision block  700 . If the answer in decision block  700  is yes, control is transferred to decision block  701 . 
     Decision block  701  determines if a message has been received from the wireless terminal. If the answer is no, control is transferred to decision block  702 . If the answer is yes in decision block  701 , control is transferred to block  704  which performs the action specified in the message before transferring control to decision block  702 . Decision block  702  determines if there has been any type of switch actuation on the auxiliary desktop unit. If the answer is no, control is transferred back to decision block  700 . If the answer is yes in decision block  702 , block  703  forms a message specifying the switch actuation and sends this message to the wireless terminal before transferring control back to decision block  700 . 
     FIGS. 8 and 9 illustrate, in flowchart form, the operations performed by wireless switching system  201  in implementing the invention. Wireless switching system  201  stores internally Tables  1 ,  2 , and  3  of FIGS. 10-15. FIGS. 10-12 illustrate the initial state of the previous example. Table  1  of FIGS. 10 and 13 define for each wireless terminal the fixed unit or auxiliary unit with which the wireless terminal is in contact. Table  1  also defines if the wireless terminal is part of a call coverage group, the number of that group, and its type. The call coverage groups are set forth in Tables  2  and  3 . Table  2  of FIGS. 11 and 14 define the location call coverage groups. The covered telephone number for a location coverage group is the number assigned to that location. For example, location call coverage group  1  provides coverage for the number assigned to cubicle area  213  which is  8213 . Table  3  of FIGS. 12 and 15 defines the preassigned call coverage. groups. If an auxiliary unit is part of the preassigned call coverage group then its position remains constant within that call coverage group regardless of the wireless terminal that is in communication with the auxiliary unit. This is illustrated in Table  3  of FIGS. 12 and 15 for auxiliary unit  102 . Initially in the previously example, wireless terminal  101  was in contact with auxiliary unit  102  and was part of call coverage group number  1  for call coverage type P as illustrated in Table  1 . Table  3  of FIG. 12 illustrates that wireless terminal  101  is the first terminal in call coverage group  1  for the covered telephone number  203 . Wireless terminals  207  and  208  complete the call coverage group illustrated in Table  3 . Table  1  of FIG. 10 shows that wireless terminals  207  and  208  were in contact with fixed unit  216  but assigned to the call coverage group  1  of Table  3 . Table  1  of FIG. 10 illustrates that wireless terminals  204 - 206  were initially part of a location coverage group for area  213 . Table  2  also illustrates this fact. 
     When wireless terminal  101  moves from communication with auxiliary unit  102  to location  213  and communication with fixed unit  215 , Table  1  is updated as illustrated in FIG.  13 . Wireless terminal  101  is shown as communicating with fixed unit  215  and being part of call coverage group number  1  as illustrated in Table  2  of FIG.  14 . When wireless terminal  101  shifted to location  213 , wireless terminal  206  entered secretarial office  212  and commenced communication with auxiliary unit  102 . Wireless terminal  206  then becomes part of call coverage group  1  of preassigned coverage groups as illustrated in Table  3  of FIG.  15 . Note, that wireless terminal  206  is the first wireless terminal in the call coverage path for wireless telephone  203  of Table  3  as illustrated in FIG.  15 . Tables  1  and  2  were also updated in FIGS. 13 and 14, respectively, to reflect the movement of wireless terminal  206 . 
     Turning now to the operations performed by wireless switching system  201  as illustrated in FIGS. 8 and 9, decision block  801  determines if a message has been received from a wireless terminal. If the answer is no, normal processing is performed by block  802  before returning control to decision block  801 . This normal processing includes transmitting messages to the wireless terminals and performing other standard call processing operations. If the answer in decision block  801  is yes, decision block  803  determines if an identification code or a no contact message has been received from a wireless terminal. A no contact message is transmitted by a wireless terminal when the wireless terminal is not in communication with a fixed unit or an auxiliary unit. If the answer in decision block  803  is no, then the message received from the wireless terminal is processed in a normal manner by block  804  before returning control to decision block  801 . 
     If the decision in decision block  803  is yes, decision block  806  determines if the wireless terminal is presently in a call coverage group. This determination is made by examining Table  1  of FIG. 10 or  13 . If the answer is no in decision block  806 , control is transferred to decision block  811 . Assuming that the answer is yes in decision block  806 , decision block  807  examines Table  1  to determine in which call coverage group the wireless terminal is present. If the wireless terminal is in a location call coverage group, control is transferred to block  808  which performs the necessary administration operations on Table  2  to remove the wireless terminal from the location call coverage group. In the previous example, where wireless terminal  206  left cubicle area  213 , Table  2  was updated to reflect that wireless terminal  206  was no longer part of location call coverage group  1  as illustrated in FIG.  14 . After execution of block  808 , control is transferred to decision block  81   1 . 
     Returning to decision block  807 , if the answer is that the wireless terminal is not part of a location call coverage group, then the wireless terminal is part of a preassigned call coverage group, and block  809  performs the necessary administrative functions on Table  3  to remove the wireless terminal from Table  3 . When wireless terminal  101  left secretarial office  212 , reference to wireless terminal  101  was removed from Table  3  as illustrated in FIG.  15 . After execution of block  809  or block  808 , control is transferred to decision block  811 . Decision block  811  now determines from the message received from the wireless terminal if there is an identification code for either a fixed unit or an auxiliary unit present in the message. If the answer is no, then control is transferred back to decision block  801 . If the answer is yes, in decision block  811 , control is transferred to decision block  901  of FIG.  9 . 
     Decision block  901  determines if the identification code in the message from the wireless terminal is the identification code of an auxiliary unit. If the answer is yes, decision block  902  determines if the auxiliary unit is part of a preassigned call coverage group by examining Table  3 . In the case of auxiliary unit  102 , the answer would be yes. If the answer is no in decision block  902 , control is transferred back to decision block  801  of FIG.  8 . If the answer is yes in decision block  902 , block  903  administers Table  3  to add the wireless terminal into the proper call coverage group and position within that group as defined by the auxiliary unit positioned within the call coverage group. Block  904  then administers Table  1  to reflect the call coverage group of which the wireless terminal is part before transferring control back to decision block  801  of FIG.  8 . 
     Returning to decision block  901 , if the identification information is not an auxiliary unit, then the identification unit must be that for a fixed unit, and control is transferred to decision block  906 . The latter decision block examines Table  1  to determine whether the identification information defines a new fixed unit or the fixed unit with which the wireless terminal is presently communicating. If the answer in decision block  906  is no, then, no more processing is required, and control is transferred back to decision block  801  of FIG.  8 . If the answer is yes in decision block  906 , decision block  907  determines if the location has a call coverage group assigned to it. If the answer is no, control is transferred back to decision block  801  of FIG.  8 . If the answer is yes in decision block  907  that there is a location call coverage group assigned to the new location, block  908  administers Table  2  to properly add the wireless terminal into that location call coverage group. In the present example, Table  2  of FIG. 14 illustrates that wireless terminal  101  was added into the tail of the call coverage group for location  213  serviced by telephone number  8213 . After execution of block  908 , Table  1  is updated by block  909  to reflect that the wireless terminal is now part of a new location call coverage group before control is transferred back to decision block  801  of FIG.  8 . 
     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.