Text message transmissions indicating failure of recipient mobile device to connect with a call

An originating communications device is configured to transmit a text message to a recipient mobile device when the originating device determines that the recipient device has failed to connect with a call that was initiated by the originating device. The text message is designed to indicate that the recipient device has failed to connect with the call; in addition or as an alternative, the text message includes a code that indicates to the recipient device that it is potentially in a poor RF coverage area. The recipient mobile device, upon receiving and displaying the text message, may determine that it is indeed in an area with poor coverage and will in response store its current geographic location as a poor coverage area. Other embodiments are also described and claimed.

An embodiment of the invention relates to identifying poor coverage areas in a wireless cellular network. Other embodiments are also described.

BACKGROUND

Mobile communications involve the exchange of radio frequency (RF) signals between a mobile device and a base station. When these RF signals are blocked or degraded, a call placed to the mobile device cannot be completed or connected, because the base station is unable to establish a communication link to the mobile device in response to a call origination request from another communications device. The base station may be unable to establish the communication link to the mobile device for various reasons. For example, the control signals for call setup that are transmitted from the base station to the mobile device may be blocked, reflected, absorbed, or attenuated before they reach the mobile device.

When a base station is unable to establish a communication link to a recipient mobile device, the recipient device will not ring. Thus, it will not provide any indication to its user that it had failed to connect with an incoming call as a result of poor coverage, unless a user of an originating communications device leaves a voicemail or a callback number (when prompted to do so by a pre-recorded carrier message). If the user of the originating device decides to not leave a voicemail or a callback number, her other option may be to try calling again in a few minutes. However, she may simply forget to call again altogether. In that situation, the user of the recipient device may never know that he had missed a call from the user of the originating device.

SUMMARY

In accordance with the embodiments of the invention, an originating (near-end user's) communications device may send a text message to a recipient (far-end user's) mobile device to alert the far-end user that the recipient device is likely in a poor radio frequency (RF) coverage area. When the originating device initiates a call with the recipient device and the recipient device fails to connect with the call, the originating device may automatically determine that the recipient device is likely in an area with poor RF coverage, by virtue of its failure to connect with the call. The originating device may generate a text message that indicates the failure of the recipient device to connect with the call. The originating device then transmits the text message to the recipient device. Once received by the recipient device, the display of this text message may prompt the far-end user to call the near-end user back, without requiring the near-end user to leave a voicemail.

In another embodiment, a recipient mobile device may store its geographic location as a poor RF coverage area in response to receiving a text message from an originating communications device that indicates the recipient device may be in a potentially poor RF coverage area. After the recipient device receives the text message and determines that the text message is a poor RF coverage alert, the recipient device may determine that it is receiving a weak RF signal and in that case determines its current geographic location. The recipient device then stores the geographic location as a poor RF coverage area. This may enable the user of the recipient device to anticipate poor RF coverage when the user approaches an area indicated by the stored geographic location. The user can then determine appropriate actions to take before the user reaches the area of poor RF coverage.

DETAILED DESCRIPTION

Several embodiments of the invention with reference to the appended drawings are now explained. While numerous details are set forth, it is understood that some embodiments of the invention may be practiced without these details. In other instances, well-known circuits, structures, and techniques have not been shown in detail so as not to obscure the understanding of this description.

FIG. 1shows an example of a mobile communications system. The system may include an originating communications device2(i.e., a device which initiates a communications request) and a recipient mobile device3(i.e., a mobile device to which the communications request is targeted). Although the system may include several originating devices2and recipient devices3, only one of each is shown inFIG. 1to simplify the drawing. Originating device2and recipient device3may include any suitable device for sending and receiving communications requests and participating in communications interactions. For example, the mobile devices3may include a cellular telephone, a smart phone, or any other portable wireless device that is capable of two-way real-time voice communications or “calls,” such as voice calls and video calls. The originating communications device2may also be a mobile device.

The originating device2communicates with the recipient device3through a wireless communications network1. The network1supports calls and other traffic, such as text messaging, to and from mobile communications devices. Any suitable circuitry, software, device, system, or a combination of these (e.g., a wireless communications infrastructure including cellular network communications towers or base stations, and telecommunications servers and switches) operative to create a communications network may be used to create the network1. The network1may be configured in accordance with any technology suitable for mobile communications such as General Packet Radio Service (GPRS), Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA), Universal Mobile Telecommunications System (UMTS), Integrated Dispatch Enhanced Network (iDEN), 3G technologies, etc. In some embodiments, the network1may also support traditional telephone lines (Plain Old Telephone System, POTS), voice over wireless local area network or WiFi (e.g., a IEEE 802.11 protocol), high frequency systems (e.g., 900 MHz, 2.4 GHz, and 5.6 GHz communications systems), infrared, other relatively localized wireless communication protocol, or any combination thereof.

The wireless network1may include a base station9with an associated antenna5, a base station8with an associated antenna4, a mobile switching center10, a messaging service controller12, a Short Message Service Center (SMSC)15, a voicemail service center16, and a home location register (HLR)11. The base station9and the antenna5provide wireless network coverage for a particular coverage area referred to as a cell7. The base station8and the antenna4provide wireless network coverage for a cell6. The wireless network1transmits communication signals to and receives communication signals from mobile devices within the cell7via the antenna5and within the cell6via the antenna4. Those skilled in the art will appreciate that a wireless network in actual practice may include hundreds of cells, each served by an antenna, depending upon an overall expanse of network coverage. All pertinent components may be connected by multiple switches and routers (not shown) and controlled by multiple network controllers.

The messaging service controller12routes voicemail messages to the voicemail service center16and text messages to the SMSC15. The base station9communicates with the messaging service controller12by a network, such as the Internet and/or a POTS (plain ordinary telephone system) via the mobile switching center10. Typically, the Internet connection between the messaging service controller12and the mobile switching center10transfers data, and the POTS connection transfers voice information. The base station9may transmit and receive text messages from mobile devices such as the recipient device3, and the base station8may transmit and receive text messages from mobile devices such as the originating device2, by short message service (SMS) or other known over-the-air methods. The phrase “text message” as used here generically refers to brief alphanumeric content that can be exchanged between an originating fixed-line or landline phone or a mobile phone, and a mobile phone (over a network). This may be in accordance with a Short Message Service (SMS) protocol or a Multimedia Message Service (MMS) protocol.

In GSM technology, an SMS text message is sent to and from a mobile device over a control channel. When the mobile device is in idle mode (i.e., the mobile device is not currently connected to a call), a Standalone Dedicated Control Channel (SDCCH) may be used for sending SMS text messages to and from the mobile device. The SDCCH is a much lower bandwidth channel than a traffic channel (TCH) which is used for transferring data during a voice call. The probability of receiving an SMS text message is therefore greater than receiving a voice call.

The HLR11is a database that stores records corresponding to mobile devices that are authorized to use the network1. The HLR11provides initial log-on registration, authentication, and billing support. For each mobile device, the HLR11stores the location of a cell that is currently serving the mobile device. The mobile switching center10determines the routing of calls and traffic to mobile devices based on an inquiry to the HLR11.

In the embodiment shown inFIG. 1, the originating device2is within the cell6served by the antenna4. The recipient device3is within the cell7served by the antenna5. Within the cell is a building13that is located between the recipient device3and the antenna5. The building13is oriented and constructed such that it degrades the RF signals transmitted between the recipient device3and the antenna5, resulting in a RF degradation zone14. In this case, a call (which may be any two-way communication such as a voice call or a video call) placed to the recipient device3may have a substantial likelihood of not being completed, i.e., the network1may not be able to establish a communication link (also referred to as a connection) to the recipient device3in response to a call initiation request. However, the RF signals transmitted from the antenna5to the recipient device3may be such that the recipient device3may still be able to receive text messages.

FIG. 2is a block diagram of an example mobile device20according to an embodiment of the invention. Both originating device2(FIG. 1) and recipient device3(FIG. 1) may include some or all of the components of mobile device20. The mobile device20is a portable wireless two-way communications device having at least voice and data communication capabilities, such as a cellular telephone, a smart phone, or any other portable device with similar wireless communication capabilities. The mobile device20includes components such as an antenna21, a RF transceiver22, receiving (RX) processing circuitry29, and transmission (TX) processing circuitry28. The mobile device20also includes a main processor36that interacts with a signal strength detector30, a geoposition locator31, memory37, storage23, a speaker32, a microphone33, a display34, and a user interface35. In addition to the speaker32and the display34, mobile device20may include other output mechanisms, e.g., hardware to cause the device to vibrate or flashing LED lights. The various components of the mobile device20may be digitally interconnected and used or managed by a software stack being executed by the main processor36. Many of the components shown or described here may be implemented as one or more dedicated hardware units and/or a programmed processor (software being executed by a processor, e.g., the main processor36).

RF transceiver22receives, from antenna21, an incoming RF signal transmitted by a base station of a wireless communication network. RF transceiver22may down-convert the incoming RF signal to produce a baseband signal. The baseband signal is sent to RX processing circuitry29that produces a processed baseband signal by filtering, decoding, and/or digitizing the baseband signal. RX processing circuitry29provides the processed baseband signal to the processor36. The processor36may transmit the processed baseband signal to the speaker32(e.g., voice communications) or perform further processing of the processed baseband signal for display to the user (e.g., data communications such as text messaging and web browsing). The processor36may also transmit the processed baseband signal to the signal strength detector30.

TX processing circuitry28receives voice data or other outgoing baseband data (e.g., web data, email, text message) from the processor36. TX processing circuitry28may encode, multiplex, and/or digitize the outgoing baseband data to produce a processed baseband signal. RF transceiver22receives the outgoing processed baseband signal and may up-convert the baseband signal to an RF signal that is transmitted via antenna21.

The signal strength detector30monitors and processes the strength of a received RF signal from a base station. If the signal strength falls below a certain threshold, the processor36performs certain actions related to seamless mobility. The processor36also uses the information from the signal strength detector30to update a received signal strength indicator (RSSI) that is displayed to a user as an RSSI icon via the display34. The RSSI icon is modified whenever the received signal changes in level, for example when it rises or falls beyond predefined levels. This may be done by changing the number of bars or height of a bar in the RSSI icon.

The geoposition locator31enables the mobile device20to determine its current geographic position. Such position may be obtained by a global positioning system (GPS). Using a GPS, the mobile device20can ascertain its present geographic location (latitude, longitude, and altitude), by the detection and processing of signals from geo-synchronous satellites. The mobile device20may use other alternative systems to determine its geographic location, such as line-of-sight, dead reckoning, wireless triangulation, or an equivalent location determination system.

The main processor36controls the overall operation of the mobile device20by performing some or all of the operations of one or more applications implemented on the mobile device20, by executing instructions for it (software code and data) that may be found in the storage23. The processor may, for example, drive the display34and receive user inputs through the user interface35(which may be integrated with the display34as part of a single, touch sensitive display panel on the front face of the mobile device20). The main processor36may also control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceiver22, the RX processing circuitry29, and the TX processing circuitry28. The main processor36may also control and/or interface with the geoposition locator31to obtain the location of the mobile device20and transfer the location to storage23. In addition, the processor may perform various operations related to call processing and text messaging.

Storage23provides a relatively large amount of “permanent” data storage, using nonvolatile solid state memory (e.g., flash storage) and/or a kinetic nonvolatile storage device (e.g., rotating magnetic disk drive). Storage23may include both local storage and storage space on a remote server. Storage23may store data, such as poor coverage locations27, and other software components that control and manage, at a higher level, the different functions of the mobile device20. For instance, there may be a telephony application26that configures a built-in touch sensitive display to look like the keypad of a traditional telephony handset, and allows the user to enter a telephone number to be called, or select a previously stored number from a telephone address book. The telephony application26may register the media device as a cellular handset with the nearest cellular base station (using the appropriate cellular communications protocols built into the mobile device20). The application then proceeds to allow the user to make a call, and controls the built-in microphone33and earpiece speaker32to enable the user to experience a two-way conversation during the call. Another application may be a text messaging application24that would allow the user to send and receive text messages through the user interface35and display34.

In addition to storage23, there may be memory37, also referred to as main memory or program memory, which provides relatively fast access to stored code and data that is being executed by the main processor36. Memory37may include solid state random access memory (RAM), e.g., static RAM and dynamic RAM. There may be one or more processors, e.g., main processor36, that run or execute various software programs, modules, or sets of instructions (e.g., applications) that, while stored permanently in the storage23, have been transferred to the memory37for execution, to perform the various functions described above. It should be noted that these modules or instructions need not be implemented as separate programs, but rather may be combined or otherwise rearranged in various combinations. In addition, the enablement of certain functions could be distributed amongst two or more modules, and perhaps in combination with certain fixed hardware components that contain hardwired logic.

FIG. 3shows a flowchart of operations that may be performed by the originating device2ofFIG. 1according to an embodiment of the invention. A user of the originating device2(near-end user) initiates a call to the recipient (far-end user's) mobile device3(in block40) by, for example, dialing or retrieving a phone number of the recipient device3and pressing a send button. The base station8receives from the originating device2the request to initiate the call with the recipient device3. When the base station8receives the request, it transmits the request to the mobile switching center10which queries the HLR11for the current location of the recipient device3.

According to the embodiment shown inFIG. 1, the mobile switching center10may recognize that the recipient device3is within the cell served by the antenna5and the base station9based on an inquiry to the HLR11. The mobile switching center10routes the call initiation request to the base station9. The base station9communicates with the recipient device3over a control channel to establish a communication link over a TCH for connecting the call. If a communication link between the base station9and the recipient device3is established, the call is completed (i.e., the recipient device3successfully connected with the call). The originating device2determines that the recipient device3has successfully connected with the call (in block41), and the process shown inFIG. 3ends (in block42). The originating device2may determine that the recipient device3connected with the call by, for example, detecting a predetermined, minimum number of rings before the call is answered, by being either “picked up” by the far-end user or routed to voicemail. The originating device2may also determine that the recipient device3has connected with the call, by detecting speech of the near-end user with its microphone, within a specified period of time after the call is answered.

If the recipient device3does not receive the control signal from the base station9or if a communication link over a TCH cannot be established between the base station9and the recipient device3, the call cannot be completed (i.e., the recipient device3has failed to connect with the call). A call may also fail to complete when the base station9determines that the recipient device3is not currently registered with the network1(i.e., the recipient device3is currently not powered on or is not within any RF coverage area). Because no RF traffic channel is available for connecting the call to the recipient device3, the call cannot be completed. The originating device2determines that the recipient device3has failed to connect with the call (in block41) by, for example, detecting no rings or too few rings (fewer than the predetermined minimum), before the call is routed to the voicemail of the far-end user or a pre-recorded carrier message (e.g., a previously determined audible voice or tones) is played back, or detecting a non-audible code sent by the network1indicating that a communication link to the recipient device3could not be established.

When the originating device2determines that the recipient device3has failed to connect with the call, the originating device2generates a text message that indicates a failure of the recipient device3to connect with the call (in block44). Before generating the text message, the originating device2may prompt the near-end user to confirm that the text message is to be sent to the recipient device3(in block43). Alternatively, the originating device2may generate the text message without prompting the near-end user. The text message may include information that indicates the recipient device3missed the call from the originating device2. The text message may alternatively, or in addition, include a code that indicates the recipient device3is currently in an area of potentially poor RF coverage. After generating the text message, the originating device2transmits the text message to the recipient device3via the network1(in block45).

When the base station8receives the text message from the originating device2, the text message may be forwarded to the SMSC15. If the recipient device3is currently registered, the SMSC15identifies the base station that is serving the recipient device3based on an inquiry to the HLR11and routes the text message to the base station9which transmits the text message to the recipient device3on a control channel (e.g., the SDCCH) that is established between the antenna5and the recipient device3. If the recipient device3is currently not registered, the SMSC15may store the text message until the recipient device3registers with the network1or until a specified period of time has elapsed. When the recipient device3registers with the network1, the SMSC15will transmit the text message to the mobile switching center10via the messaging service controller12. The mobile switching center10then routes the message to the base station9. The base station9then transmits the text message to the recipient device3on a control channel (e.g., the SDCCH). If the recipient device3does not register with the network before a specified period of time has elapsed, the text message may be cleared from the SMSC15without being transmitted to the recipient device3.

Because the base station9is unable to establish a communication link over a traffic channel to the recipient device3to complete the call, the base station9cannot instruct the recipient device3to play a ringtone to announce the call. The user of the recipient device3thus generally receives no indication that she had missed a call. However, the recipient device3may still be able to receive the text message because the signal strength required to transmit a text message over the control channel is less than that needed to establish and maintain a call over a traffic channel. In another example, the recipient device3may be in an area where the RF signal received by the recipient device3fluctuates, e.g., perhaps due to movement of the recipient device3, such that the recipient device3may be unable to connect to the call due to insufficient RF signal at the time the call was initiated but may shortly thereafter have sufficient RF signal to be able to receive the text message (e.g., when the recipient device3reestablishes a connection to the network1). Thus, even though the recipient device3is located in a “poor RF coverage area,” the recipient device3may still receive the text message. The poor RF coverage area includes the current location of the recipient device which has sufficient RF signal for receiving text messages by may or may not have sufficient RF signal for receiving a call.

FIG. 4shows a flowchart of operations that may be performed by the recipient mobile device3ofFIG. 1according to an embodiment of the invention. The recipient device3receives a text message from the base station9on a control channel established between the recipient device3and the antenna5(in block46). In response to receiving the text message, the recipient device3determines whether the text message is a poor RF coverage alert (in block47). The recipient device3may make this determination by, for example, parsing the text message and detecting a predetermined code25(SeeFIG. 2) that is included in the text message and that indicates the recipient device3is currently in a potentially poor RF coverage area. If the recipient device3determines that the text message is not a poor RF coverage alert, the process shown inFIG. 4ends (in block48).

If the recipient device3determines that the text message is a poor RF coverage alert, the recipient device3then determines the strength of the RF signal that is received from the antenna5(in block49) using a signal strength detector. The recipient device3may determine the signal strength by measuring an instantaneous value of the signal strength or by measuring the signal strength over a period of time. If the signal strength does not drop below a predetermined threshold, the recipient device3is not currently in an area of poor RF coverage, and the process shown inFIG. 4ends (in block48).

If the signal strength does drop below a predetermined threshold, the recipient device3may currently be in an area of poor RF coverage. In response to determining that it is in a poor RF coverage area, the recipient device3determines its current geographic location (in block50) using a geoposition locator. The recipient device3stores this location as a poor RF coverage area (in block51).

When the recipient device3later approaches the area that is indicated by the stored location (by comparing newly generated geographic location parameters to the stored location parameters), the recipient device3may provide a warning alert so that the user of the recipient device3can take appropriate action (in block52). The warning alert may be provided to the user audibly, textually, visually, and/or haptically. For example, if the user is operating the recipient device3to make a call while in a poor coverage area, the recipient device3may provide an audible alert to the user. The audible alert may be a tone to alert the user or an audio recording informing the user that she is currently in an area of poor RF coverage. The user can then decide whether to postpone making the call until she leaves the area of poor RF coverage. As another example, the recipient device3may vibrate and/or provide visual cues such as flashing lights or a symbolic icon when the user of the recipient device3is near a poor coverage area.

FIG. 5shows an example of a text message alert58that is sent from the originating device2and displayed by the recipient device3according to an embodiment of the invention. The recipient device3may include a display screen54. The display screen54may present various types of information to the user, such as an RSSI icon56, a battery indicator57, the current time55, and the text message alert58. Additionally, the display screen54may also be combined with a user interface component such as a touch screen. The recipient device3may also include one or more physical buttons and/or virtual buttons (on the touch screen).

The text message alert58may be presented to the user of the recipient device3through the display screen54. The text message alert58may include a code512that indicates the recipient device3is currently in a potentially poor RF coverage area. The recipient device3may parse a received text message to determine if the code512is present. If the code512is present, the received text message is a text message alerting the user of the recipient device3that it is currently in a potentially poor RF coverage area. The text message alert58may also include information that indicates the recipient device3missed a call from the originating device2. For example, the text message may include a date and time that the text message alert58was created by the originating device2. The text message alert58may also include a notification such as “I am trying to call you now but cannot connect to your phone.” The text message alert58includes a signature that is used by the recipient device3to identify the originating device2. For example, such information may include names, contact information (e.g., phone number), device identification code, and any other types of appropriate identification information.

For purposes of explanation, specific embodiments of the invention have been described to provide a thorough understanding of the present invention. These should not be construed as limiting the scope of the invention but merely as illustrating different examples and aspects of the invention. It should be appreciated that the scope of the invention includes other embodiments not discussed in detail above. Various other modifications, changes, and variations which will be apparent to those skilled in the art may be made in the arrangement, operation, and details of the systems and methods of the present invention disclosed herein without departing from the spirit and scope of the invention as defined in the appended claims. For instance, the originating device2is depicted inFIG. 1as a mobile device; however, it may alternatively be a landline-based unit such as a desktop personal computer running a VoIP telephony application program that is linked with a text messaging application program. Therefore, the scope of the invention should be determined by the claims and their legal equivalents. Such equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure. Furthermore, no element, component, or method step is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims.