Abstract:
A method for a wireless device to automatically and dynamically determine if the current system in which it is operating is capable of offering data service connectivity. The present invention requires no intervention on the part of the user. According to the method of the present invention, a call origination signal from a wireless device is automatically transmitted to a base station. The call origination signal contains a request for electronic data transmission services. The wireless device detects whether a reply to the call origination signal has been received from the base station. If a reply has been received, the wireless device detects whether the data service request has been rejected. If the detected reply does not reject the data service request, then an indication of availability of the data service is displayed on the wireless device. If the detected reply does reject the data service request, then an indication of non-availability of the data service is displayed on the wireless device.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates generally to the field of mobile communications. More particularly, the present invention relates to a method for determining whether electronic data transmission services are available for a wireless device.  
           [0003]    2. Related Art  
           [0004]    A variety of multiple access communication systems have been developed for transferring information among a large number of system users. Typically, in such systems, a user of a wireless device must make an actual attempt to connect to an electronic data transmission service, such as the Internet, to determine whether data service connectivity is supported. Failure to connect the wireless device to the electronic data transmission service can indicate one of two things. Either the system does not support data service connectivity, or the system was heavily loaded, making data service connectivity currently unavailable. The user, short of calling the service provider, never fully knows why the data service connection failed.  
           [0005]    What is needed is a method for enabling a wireless device to automatically indicate its ability for wireless data service connectivity to the user. What is also needed is the ability to have the wireless device automatically change the indication as the ability for data service connectivity changes. Thus, what is further needed is a method for a wireless device to automatically determine whether or not data service connectivity is available without user intervention.  
         SUMMARY OF THE INVENTION  
         [0006]    The present invention satisfies the above mentioned needs by providing a method for a wireless device to automatically and dynamically determine if the communication system in which the wireless device is operating is capable of offering data service connectivity. The present invention requires no interaction on the part of the user. According to the method of the present invention, a call origination signal from a wireless device is automatically transmitted to a base station. Alternatively, the wireless device might scan overhead messages sent by the base station—such as for example Extended System Parameters messages—to determine if the base station supports data services. Such indications could be PZID, MAC_CF_SUPPORTED, or any other indication that might be added to the standard later. The call origination signal contains a request for electronic data transmission services. The wireless device detects whether a reply to the call origination signal has been received from the base station. If a reply has been received, the wireless device detects whether the electronic data transmission service request has been rejected. If the detected reply does not reject the electronic data transmission service request, then an indication that data service connectivity is available is displayed via the user-interface of the wireless device. The indication could be an LED, sound, vibration, etc. Thus, the indication is not restricted to a display on an LCD screen. If the detected reply does reject the electronic data transmission service request, then an indication that data service connectivity is not available is displayed on the user-interface of the wireless device.  
           [0007]    Most of the communications performed during the determination of whether access to electronic data transmission services is available are done over paging and access channels. Potentially few message units are used during the communication. Therefore, only a minimal amount of interference is introduced to the communication system.  
           [0008]    The method of the present invention conforms to the IS95B standard, which contains information on how a base station and mobile device communicate. The method of the present invention also conforms to the IS2000 standard. Thus, no changes to the IS95B standard are required, and more importantly, no hardware or software changes to existing base stations are required.  
           [0009]    Further features and advantages of the invention, as well as the structure and operation of various embodiments of the invention, are described in detail below with reference to the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0010]    The accompanying drawings, which are incorporated herein and form part of the specification, illustrate the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention.  
         [0011]    [0011]FIG. 1A is a diagram illustrating an exemplary communication system in which the present invention may be implemented.  
         [0012]    [0012]FIG. 1B is a block diagram illustrating an exemplary wireless device.  
         [0013]    [0013]FIG. 2A, 2B,  2 C, and  2 D are diagrams illustrating exemplary symbols/icons for display on a wireless device&#39;s user-interface indicating to the user whether data service connectivity is or is not available according to an embodiment of the present invention.  
         [0014]    [0014]FIG. 3 is a flow diagram illustrating origination of a data query from a wireless device to a base station when a channel assignment is received from the base station according to an embodiment of the present invention.  
         [0015]    [0015]FIG. 4 is a flow diagram illustrating origination of a data query from a wireless device to a base station when a rejection with reason is received from the base station according to an embodiment of the present invention.  
         [0016]    [0016]FIG. 5 is a flow diagram illustrating origination of a data query from a wireless device to a base station when a rejection without reason is received from the base station according to an embodiment of the present invention.  
         [0017]    [0017]FIG. 6 is a flow chart illustrating a method for a wireless device to automatically and dynamically determine whether the communication system in which the wireless device is operating offers data service connectivity according to an embodiment of the present invention.  
         [0018]    [0018]FIG. 7 is a flow chart illustrating an alternative method for a wireless device to automatically and dynamically determine whether the communication system in which the wireless device is operating offers data service connectivity that employs a system identification/network identification (SID/NID) list according to an embodiment of the present invention. 
     
    
       [0019]    The features, objects, and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawings in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0020]    While the present invention is described herein with reference to illustrative embodiments for particular applications, it should be understood that the invention is not limited thereto. Those skilled in the art with access to the teachings provided herein will recognize additional modifications, applications, and embodiments within the scope thereof and additional fields in which the present invention would be of significant utility.  
         [0021]    The present invention can be applied for use in various types of wireless communication systems. The preferred mode of operation is in a CDMA system. However, the principals of the invention can be readily adopted for use in TDMA, FDMA, WCDMA, HDR, or other types of wireless communication systems.  
         [0022]    The present invention is a method for determining data service connectivity for a wireless device in a wireless communication system. FIG. 1 is a diagram of an exemplary wireless communication system  100  in which the present invention may be implemented. Communication system  100  comprises a wireless device  102  having a first antenna  104 , a base station  106  having a second antenna  108 , and a public switched telephone network (PSTN)  110 . Base station  106  is coupled to PSTN  110 . PSTN  110  is shown in phantom to be coupled to land-based services, such as voice (a telephone  112 ) and data (an electronic data transmission service network  114 ). In one embodiment, base station  106  may also be coupled to an IWF (inter-working function) and the INTERNET™ (shown in phantom in FIG. 1), in addition to being coupled to PSTN  110 .  
         [0023]    Examples of wireless device  102  may include, but are not limited to, a cellular telephone, a personal digital assistant (PDA), a pager, etc., or any combination thereof. Base station  106  is a fixed device for enabling a wireless device, such as wireless device  102 , to communicate with land-based voice and data services, such as telephone  112  and electronic data transmission service network  114 . Although base station  106  is shown as being capable of connecting to electronic data transmission service network  114  via PSTN  110 , not all base stations have the ability to connect to electronic data transmission services. Base station  106  is also capable of enabling wireless device  102  to communicate with other wireless devices (not shown). Wireless device  102  and base station  106  communicate over the air via first and second antennas  104  and  108 , respectively.  
         [0024]    The present invention also provides the user of wireless device  102  with an indication of whether or not data service connectivity is available in the particular area in which the user is presently located. The user is provided this indication without having to first make a connection attempt. A determination is automatically made as to whether access to electronic data transmission services is available without any user interaction. Once it is determined whether access to electronic data transmission services is available, an indicator is displayed to the user via the user-interface of wireless device  102 .  
         [0025]    [0025]FIG. 1B is a block diagram of an exemplary wireless device  102 . In a preferred embodiment, wireless device  102  is a wireless telephone. Wireless telephones are stand alone units that exchange radio frequency (RF) signals via wireless communication systems, such as wireless communication system  100 . Examples of wireless telephones include portable, mobile, or fixed cellular and satellite telephones. In alternative embodiments, wireless device  102  may be any device that interfaces to a wireless communication system, such as a pager, a personal digital assistant (PDA), a wireless computer, etc.  
         [0026]    Wireless device  102  comprises a user interface  120 , one or more processors, such as processor  122 , an interface  124 , and memory  126 . User interface  120  includes a user input device  128  and one or more software components that reside in memory  126 . User input device  128  is connected to interface  124 . Interface  124  is connected to processor  122  and memory  126 .  
         [0027]    User input device  128  may be any device that accepts input from a user. In a preferred embodiment, user input device  128  is a keypad on wireless device  102 . In alternative embodiments, user input device  128  may be a keyboard, a touch screen, any other device that can accept user input, or a combination thereof.  
         [0028]    User interface  120  comprises a display as well as user input device  128 . The display enables wireless device  102  to output information to a user. The display may include, but is not limited to, light emitting diodes (LEDs), a liquid crystal display (LCD), a video display, any other display known to persons skilled in the relevant art(s), or any combination thereof.  
         [0029]    Processor  122  comprises one or more processors that have the capability to process computer software in the form of lines of executable code. The lines of executable code reside in memory  126  and may comprise commands from a plurality of computer programming languages. Processor  122  may comprise processing capability dispersed among one or more application specific integrated circuits (ASICs) or other hardware capable of processing computer software. ASICs are well known to persons skilled in the relevant art(s). The Mobile Station Modem™ chip is an ASIC suited for wireless device  102  because it is designed for use in wireless communication applications and incorporates code division multiple access (CDMA) functionality. Exemplary processors  122  may also include the Advanced RISC Machines (ARM®) microprocessor and the Intel  186  processor.  
         [0030]    Interface  124  is any communication bus that allows the functional connectivity of components within wireless device  102 .  
         [0031]    Memory  126  is any storage medium capable of storing information. Examples of memory  126  include short term memory, long term memory, random access memory (RAM), read only memory (ROM), non-volatile memory, removable memory such as a floppy disk, or any other memory that can be used to store computer code or information processed by computer software. Memory  126  may be dispersed among one or more hardware storage medium components. In a preferred embodiment, memory  126  can retain stored data even when wireless telephone  102  is powered down.  
         [0032]    [0032]FIGS. 2A, 2B,  2 C, and  2 D are diagrams illustrating exemplary symbols/icons  200  for display on wireless device  102 &#39;s user-interface that indicate whether data service connectivity is or is not available according to an embodiment of the present invention. FIG. 2A shows a letter “I”  202  enclosed within a rectangular region  204  for indicating that access to electronic data transmission services is available. FIG. 2B shows letter “I”  202  enclosed in an oval region  206  for indicating that access to electronic data transmission services is available. FIG. 2C shows a broken letter “I”  208  enclosed in rectangular region  204  for indicating that access to electronic data transmission services is unavailable. FIG. 2D shows broken letter “I”  208  enclosed in oval region  206  for indicating that access to electronic data transmission services is unavailable. As the ability for access to electronic data transmission services changes, symbol/icon  200  dynamically changes accordingly.  
         [0033]    Although the present invention uses symbols/icons representative of the letter “I” enclosed in rectangular and oval regions, the present invention is not limited to these symbols/icons. One skilled in the art would know that other letters within object regions or other symbols/icons may be used as indicators without departing from the scope and spirit of the present invention. Other examples of indicators that may be used to display the availability/unavailability of data service connectivity may include, but are not limited to, LED(s), a buzz or beep sound, a blinking/non-blinking indicator, etc.  
         [0034]    As previously stated, not all wireless service providers support access to electronic data transmission services. Also, access to electronic data transmission services may not be supported in all areas. Therefore, wireless device  102  may not be able to access electronic data transmission service network  114  because the communication system in which wireless device  102  is located does not support data service connectivity or the service provider for wireless device  102  either does not support data in its infrastructure or does provide data service, but has not yet rolled out this service in the current cell.  
         [0035]    Access to electronic data transmission services is determined via communications between wireless device  102  and base station  106 . The present invention is applied automatically by wireless device  102 . No user interaction is required. Wireless device  102  originates a call requesting electronic data transmission services to base station  106 . Base station  106  responds in one of three ways: (1) a channel assignment; (2) a release order specifying that the requested service option is not supported; or (3) a release order with no reason specified.  
         [0036]    [0036]FIG. 3 illustrates the origination of a call from wireless device  102  to base station  106  when a channel assignment is received from base station  106 . The process begins when wireless device  102  sends a data query  302  to base station  106 . The data query is an inquiry as to whether base station  106  is capable of providing electronic data transmission services to wireless device  102 . The data query is originated on an access channel.  
         [0037]    Base station  106  responds with a traffic channel assignment message  304  on a paging channel. The receipt of the traffic channel assignment indicates that electronic data transmission services are accessible. All further communication between wireless device  102  and base station  106  takes place on the assigned traffic channel.  
         [0038]    Wireless device  102  releases the call immediately, sending the release message  306  on the assigned traffic channel. The traffic channel is therefore allocated for a very short time. No actual data traffic takes place on the channel. Thus, the user should not be charged by the service provider. Some messaging/signalling does take place on the traffic channel, but this messaging does not carry user data (it is used in setting up the call).  
         [0039]    In the case of a channel assignment message from base station  106  to wireless device  102 , wireless device  102  will detect the potential for data service connectivity. The potential for data service connectivity is displayed to the user using one of the symbols/icons shown in FIGS. 2A and 2B. However, this does not mean that wireless device  102  will actually be able to make a data service connection. Other reasons may prevent the data service connection from occurring. For example, communication system  100  may be heavily loaded when the user attempt is eventually made. The call may fail due to lack of resources on base station  106 . A channel assignment message may lead to service negotiation. While base station  106  and wireless device  102  are both capable of making a data service connection, base station  106  and wireless device  102  may use different service options. For example, base station  106  may only offer service option 7, which provides Rate Set 1 packet data, while wireless device  102  may only offer service option 15, which provides Rate Set 2 packet data. Other reasons that may prevent a user from accessing electronic data transmission services include, but are not limited to, the user not paying their bills or the user not signing up for electronic data transmission services with the service provider.  
         [0040]    [0040]FIG. 4 is a flow diagram illustrating origination of a data query from a wireless device to a base station when a rejection with reason is received from the base station. The process begins when wireless device  102  sends a data query  402  to base station  106 . The data query is an inquiry as to whether base station  106  is capable of providing electronic data transmission services to wireless device  102 . The data query is originated on an access channel.  
         [0041]    Base station  106  responds with a release order  404  on the paging channel. The release order specifies that a requested service option is not supported. The exact service option requested by wireless device  102  depends on the system configuration. For example, in a Quick Net Connect system, wireless device  102  may ask for service option 12. In a packet data system, wireless device  102  may ask for one of service options 7 or 15. Service option 7 provides Rate Set 1 packet data while service option 15 provides Rate Set 2 packet data. The receipt of the release order indicates that electronic data transmission services are not accessible. An indicator showing that data service connectivity is not available will be displayed to the user of wireless device  102  using one of the symbols/icons shown in FIGS. 2C and 2D.  
         [0042]    Wireless device  102  may make additional query attempts  406  requesting a different service option, but this step is optional and at the discretion of wireless device  102 . The list of service options to try is configured by the respective service provider of wireless device  102 . If step  406  is not executed, wireless device  102  has no further interaction with base station  106  regarding the inquiry of electronic data transmission service availability.  
         [0043]    [0043]FIG. 5 is a flow diagram illustrating origination of a data query from a wireless device to a base station when a rejection without reason is received from the base station. The process begins when wireless device  102  sends a data query  502  to base station  106 . The data query is an inquiry as to whether base station  106  is capable of providing electronic data transmission services to wireless device  102 . The data query is originated on an access channel.  
         [0044]    Base station  106  responds with a release order  504  on the paging channel. The release order does not provide any reason for failing to provide electronic data transmission services. Although this is considered an inconclusive result, it is assumed that access to electronic data transmission services is not available. An indicator showing that data service connectivity is not available will be displayed to the user of wireless device  102  using one of the symbols/icons shown in FIGS. 2C and 2D.  
         [0045]    Wireless device  102  may make additional query attempts  506 , but this step is optional and at the discretion of wireless device  102 . If step  506  is not executed, wireless device  102  has no further interaction with base station  106  regarding the inquiry of electronic data transmission service availability.  
         [0046]    The method of the present invention is performed when wireless device  102  powers-up and when wireless device  102  detects a change in the system identification/network identification (SID/NID). Wireless devices, such as wireless device  102 , detect SID/NID changes by monitoring the paging channel. The detection of SID/NID changes is well known in the art. A change in SID/NID usually indicates a change in the inter-working function (IWF) which is responsible for connecting base station  106  to electronic data transmission services.  
         [0047]    The method of the present invention is also performed when inconclusive results are obtained, such as when base station  106  responds with a release order with no reason specified. Upon receipt of the release order with no reason specified, the method of the present invention may be repeated using a backoff algorithm, such as a linear backoff algorithm. The backoff algorithm is used to restrict the frequency with which the method of the present invention is repeated. Also, when wireless device  102  is in a SID/NID area with no data service connectivity potential, wireless device  102  will perform the method of the present invention periodically to determine whether the SID/NID&#39;s data service connectivity capabilities have changed.  
         [0048]    By restricting the frequency with which the method of the present invention is applied, wireless device  102  accesses communication system  100  very infrequently. This introduces minimal interference into communication system  100 , and therefore, has minimal impact on system capacity.  
         [0049]    The present invention may be implemented using hardware, firmware, software, or a combination thereof. The present invention may also be implemented in one or more processors operating in wireless device  102  (as described in FIG. 1B). In one embodiment, the invention is directed toward one or more processor systems, operating in wireless device  102 , capable of carrying out the functionality described below in FIG. 6. In another embodiment, the invention is directed toward one or more processor systems, operating in wireless device  102 , capable of carrying out the functionality described below in FIG. 7.  
         [0050]    [0050]FIG. 6 is a flow chart illustrating a method for a wireless device to automatically and dynamically determine whether the communication system in which the wireless device is operating offers data service connectivity. The steps of FIG. 6 may be implemented in hardware, firmware, software, or a combination thereof. The process begins with step  602 , where control immediately passes to step  604 .  
         [0051]    In step  604 , if the system is lost/not acquired or the SID/NID changes, all relevant timers are cleared. Control then passes to step  606 .  
         [0052]    In step  606 , communication system  100  is acquired and the SID/NID is determined. Control then passes to decision step  608 .  
         [0053]    In decision step  608 , it is determined whether the SID/NID is different than the previous SID/NID or, if the SID/NID is the same, whether it previously supported data service availability. If the SID/NID is not different from the previous SID/NID and the SID/NID supports data service availability, control then passes to step  609 .  
         [0054]    In step  609 , the data indicator is set to indicate whether data is available. Control then passes to step  610 .  
         [0055]    In step  610 , the system operates in the steady state mode in which normal operations of wireless device  102  are provided.  
         [0056]    Returning to decision step  608 , if the SID/NID is different from the previous SID/NID or, if the SD/NID is the same, but does not support data service availability, control then passes to step  612 .  
         [0057]    In step  612 , wireless device  102  automatically originates an electronic data transmission service call using a primary data service option. Control then passes to decision step  614 .  
         [0058]    In decision step  614 , it is determined whether a traffic channel assignment was received from base station  106 . If a traffic channel assignment was received from base station  106 , then control passes to step  616 .  
         [0059]    In step  616 , wireless device  102  immediately releases the call. Wireless device  102  also sets the data availability indicator (symbol/icon) to indicate that electronic data transmission services are available. Control then passes to step  618 .  
         [0060]    In step  618 , the system operates in the steady state mode in which normal operations of wireless device  102  are provided.  
         [0061]    Returning to decision step  614 , if a traffic channel assignment was not received, control then passes to decision step  620 . In decision step  620 , it is determined whether other data service options have been configured for wireless device  102 . If other data service options have been configured for wireless device  102 , then control passes to step  622 .  
         [0062]    In step  622 , wireless device  102  automatically originates an electronic data transmission service call using the next data service option. Control then passes back to step  614 .  
         [0063]    Returning to decision step  620 , if other data service options have not been configured for wireless device  102 , control then passes to step  624 . In step  624 , a backoff algorithm, such as a linear backoff algorithm, is applied. The backoff algorithm is used to restrict the frequency with which the inquiry of data service connectivity is repeated. Control then passes to decision step  626 .  
         [0064]    In decision step  626 , it is determined whether wireless device  102  should give up its inquiry as to whether electronic data transmission services are available in communication system  100 , based upon the linear backoff algorithm. If it is determined that wireless device  102  should give up its inquiry as to whether electronic data transmission services are available in communication system  100 , control then passes to step  628 .  
         [0065]    In step  628 , wireless device  102  sets the data availability indicator (symbol/icon) to indicate that electronic data transmission services are not available. Control then passes to step  618 .  
         [0066]    Returning to decision step  626 , if it is determined that wireless device  102  should not give up its inquiry as to whether electronic data transmission services are available in communication system  100 , control then passes to step  630 .  
         [0067]    In step  630 , a timer is set according to the backoff algorithm. The timer determines when the next inquiry should occur. Control then passes to decision step  632 .  
         [0068]    In decision step  632 , it is determined whether the timer has expired. If the timer has not expired, control remains with step  632 . If the timer has expired, control is passed back to step  612 , where wireless device  102  originates another electronic data transmission service call query.  
         [0069]    In an alternative embodiment, wireless device  102  stores a list of SID/NID pairs along with each SID/NID&#39;s data service connectivity potential. When wireless device  102  enters one of these SID/NID areas, wireless device  102  can examine the list to determine whether data service connectivity is available. The list can be formulated a number of ways. For example, the service provider can provide the list as part of a preferred roaming list. Alternatively, wireless device  102  can automatically store the last n SID/NID areas it has checked.  
         [0070]    [0070]FIG. 7 is a flow chart illustrating an alternative method for a wireless device to automatically and dynamically determine whether the communication system in which the wireless device is operating offers data service connectivity that employs the SID/NID list. This alternative method further reduces system load. The steps of FIG. 7 may be implemented in hardware, firmware, software, or a combination thereof. The process begins with step  702 , where control immediately passes to step  704 .  
         [0071]    In step  704 , if communication system  100  is lost or has not been acquired, or the SIDINID changes, all relevant timers are cleared. Control then passes to step  706 .  
         [0072]    In step  706 , wireless device  102  acquires communication system  100  and determines the SID/NID for communication system  100 . Control then passes to decision step  708 .  
         [0073]    In decision step  708 , it is determined whether the current SID/NID is in wireless device  102 &#39;s SID/NID database. If it is determined that the current SID/NID is in wireless device  102 &#39;s SID/NID database, then control passes to decision step  710 .  
         [0074]    In decision step  710 , it is determined whether the SID/NID entry has expired. If the current SID/NID entry has not expired, control then passes to step  714 .  
         [0075]    In step  714 , the user interface of wireless device  102  will display data service availability to reflect the information from the SID/NID database. Control then passes to step  716 .  
         [0076]    In step  716 , the system operates in the steady state mode in which normal operations of wireless device  102  are provided.  
         [0077]    Returning to decision step  708 , if it is determined that the current SID/NID is not in wireless device  102 &#39;s SID/NID database, control passes to step  712 .  
         [0078]    Returning to step  710 , if it is determined that the SID/NID entry has expired, control passes to step  712 .  
         [0079]    In step  712 , wireless device  102  automatically originates an electronic data transmission service call using a primary data service option. Control then passes to decision step  718 .  
         [0080]    In decision step  718 , it is determined whether a traffic channel assignment was received from base station  106 . If a traffic channel assignment was received from base station  106 , then control passes to step  720 .  
         [0081]    In step  720 , wireless device  102  immediately releases the call. Wireless device  102  also sets the data availability indicator (symbol/icon) to indicate that electronic data transmission services are available. Control then passes to step  722 .  
         [0082]    In step  722 , the system operates in the steady state mode in which normal operations of wireless device  102  are provided.  
         [0083]    Returning to decision step  718 , if a traffic channel assignment was not received, control then passes to decision step  724 . In decision step  724 , it is determined whether other data service options have been configured for wireless device  102 . If other data service options have been configured for wireless device  102 , then control passes to step  726 .  
         [0084]    In step  726 , wireless device  102  automatically originates a electronic data transmission services call using the next data service option. Control then passes back to step  718 .  
         [0085]    Returning to decision step  724 , if other data service options have not been configured for wireless device  102 , control then passes to step  728 . In step  728 , a backoff algorithm, such as a linear algorithm, is applied. The backoff algorithm is used to restrict the frequency in which the inquiry of data service connectivity is repeated. Control then passes to decision step  730 .  
         [0086]    In decision step  730 , it is determined whether wireless device  102  should give up its inquiry as to whether electronic data transmission services are available in communication system  100 . If it is determined that wireless device  102  should give up its inquiry as to whether electronic data transmission services are available in communication system  100 , control then passes to step  732 .  
         [0087]    In step  732 , wireless device  102  sets the data availability indicator (symbol/icon) to indicate that electronic data transmission services are not available. The SID/NID database is also updated to reflect the information obtained for the current SID/NID. Control then passes to step  722 .  
         [0088]    Returning to decision step  730 , if it is determined that wireless device  102  should not give up its inquiry as to whether electronic data transmission services are available in communication system  100 , control then passes to step  734 .  
         [0089]    In step  734 , a timer is set according to the backoff algorithm. The timer determines when the next inquiry should occur. Control then passes to decision step  736 .  
         [0090]    In decision step  736 , it is determined whether the timer has expired. If the timer has not expired, control remains with step  736 . If the timer has expired, control is passed back to step  712 , where wireless device  102  originates another electronic data transmission service call query.  
         [0091]    Conclusion  
         [0092]    The previous description of the preferred embodiments is provided to enable any person skilled in the art to make or use the present invention. While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention. Thus, the breadth and scope of the present invention should not be limited by any of the above-described embodiments, but should be defined only in accordance with the following claims and their equivalents.