DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0115] Referring to the accompanying drawings, a detailed description of the preferred embodiments and features of the present invention will be provided.

[0116] The present invention relates to a wireless handset that includes enhanced features to provide greater flexibility and optimum performance. According to an aspect of the present invention, a wireless handset is provided that permits a user to operate either within a wireless network or to communicate with another user in a direct handset-to-handset operating mode. The direct handset-to-handset communication mode provides full-duplex, two-way communication without utilizing a wireless network infrastructure. In addition, as further described herein, the wireless handset of the present invention includes features that enhance the operability and functionality of the handset. Such features include a find or locate feature that assists a handset operator in determining what other handset users are located within the operating range of the wireless handset. These and other features and aspects of the present invention will now be described in greater detail with reference to the accompanying drawings.

[0117] The wireless handset of the present invention may be implemented as a fully featured handset that is capable of operating in a wireless network, such as a cellular or PCS network, and/or to operate independent of a wireless network in a direct handset-to-handset communication mode. FIGS. 2 and 3 illustrate the main operating modes of the wireless handset of the invention. While it is preferred that the handset is provided with this dual capability or functionality, it is possible to implement the wireless handset and features of the present invention in the form of a special purpose handset that is capable of only operating in a direct handset-to-handset communication mode. Such a special purpose handset may communicate with other special purpose handsets and/or with full-featured handsets that are also capable of operating within a wireless network. In addition, it is also possible to implement the wireless handset of the present invention in the form of a handset that is capable of operating in a direct handset-to-handset communication mode and that can function as a cordless phone in cooperation with a cordless phone base station. Such a wireless handset may also be provided with the capability to operate within a wireless network, such as a cellular or PCS network. Other modifications and implementations may be realized according to the needs of the wireless handset user.

[0118] FIG. 2 illustrates a wireless network operating mode of a wireless handset, according to an aspect of the present invention. As shown in FIG. 2 , wireless handsets 42 A, 42 B may communicate with one another via a wireless network infrastructure 132 . Wireless network infrastructure 132 may be implemented utilizing conventional cellular or PCS technology. In the exemplary embodiment of FIG. 2 , wireless handset 42 A may establish wireless communication with wireless handset 42 B under the control of mobile switching center (MSC) 124 . Assuming that wireless handset 42 A is operating within a cell coverage area 145 of base station or cell site 140 , a call may be completed to wireless handset 42 B operating within cell coverage area 135 of base station or cell site 130 by use of conventional air interface technology and landlines 116 connecting the base stations to the MSC 124 . A call may also be completed if both wireless handsets 42 A and 42 B are operating within the same cell coverage area (e.g., area 135 or 145 ), in which case only one base station is involved. When operating within wireless network infrastructure 132 , calls initiated by either wireless handset 42 A or 42 B are normally assessed airtime charges or fees according to the service plans subscribed to by the users. In addition, fees may also be assessed if either handset 42 A or 42 B is roaming outside of its home market area or if certain service options are enabled.

[0119] When operating in a direct handset-to-handset communication mode, the wireless handsets 42 A, 42 B of the present invention directly establish communication between one another without use of a wireless network infrastructure. As a result, airtime charges may be avoided when the wireless handsets 42 A, 42 B are functioning in a direct handset-to-handset mode and independently of a network. As illustrated in FIG. 3 , when communicating in a direct handset mode, wireless handsets 42 A, 42 B can directly communicate with one another without the use of a base station or MSC. As further described herein, the selection and setup of a channel for providing communication between the handsets may be established through the use of a dynamic channel allocation technique or process. In such a case, predefined channels may be allocated and searched, with a channel being selected based on the channel having the least detected interference level or the first located channel providing sufficient signal strength. In addition, other channel selection and setup techniques may be utilized to avoid the need for manual channel selection and coordination by each user or operator.

[0120] As discussed above, the wireless handset of the present invention may be configured and implemented according to the level of functionality and operability that is required (e.g., direct handset mode only or with dual communication mode capabilities). FIGS. 4A and 4B illustrate exemplary components and features of a wireless handset that is capable of operating both within a wireless network and outside of a wireless network in a direct communication mode. The construction and features of wireless handset 42 in FIGS. 4A and 4B may be utilized to construct the wireless handsets 42 A or 42 B illustrated in FIGS. 2 and 3 and further described herein.

[0121] As illustrated in the exemplary block diagram of FIG. 4 A, wireless handset 42 may be implemented as a full featured wireless handset that comprises a control system 61 , an antenna 62 , a transceiver or tuner 63 , a speaker 64 , a display 65 , a keypad 66 , a microphone 67 , and memory 70 . An input/output (I/O) port 69 may also be provided for facilitating communication with various devices (such as a portable computer, modem, printer, etc.) and for downloading or loading information into memory 70 . Wireless handset unit 42 may be configured to provide all the features of a conventional cellular handset unit, in addition to the unique programming and memory configurations and contents for implementing the direct handset communication mode and other operating features of the present invention.

[0122] By way of non-limiting example, speaker 64 may comprise a conventional speaker for converting electrical audio signals received by antenna 62 into acoustic audio signals, and microphone 67 may comprise a conventional microphone for converting voice utterances of a user from acoustic audio signals into electric audio signals for transmission by antenna 62 . In addition, display 65 and keypad 66 may be implemented by conventional display and keypad devices for displaying and permitting entry of alphanumeric and other information. For instance, display 65 may comprise dedicated status lights and/or a liquid crystal display (LCD) to indicate (through flashing lights, alphanumeric messages, symbols, icons, etc.) the status of the wireless handset unit and the operating mode. Further, keypad 66 may comprise menu selection buttons and/or a conventional 12-button, alphanumeric keypad for initiating and receiving calls, and programming or selecting operating conditions for the wireless handset. The keys of keypad 66 may include dedicated keys which initialize or select certain functions of the handset or enter alphanumeric data when pressed. The keys of keypad 66 may also include “soft keys” which provide multiple functionality depending on the operating state or mode of the handset. For example, a soft key may be provided which functions as both a power (i.e., ON/OFF) switch as well as an end call (i.e., On-Hook) switch.

[0123] FIG. 4B illustrates an exemplary embodiment of the external construction and arrangement of the main components of wireless handset 42 , including antenna 62 , speaker 64 , display 65 , keypad 66 , and microphone 67 . The arrangement of these components may of course be modified or enhanced according to the needs of the user and the type of features incorporated into the handset. In addition, as discussed above, wireless handset 42 may also include an I/O port 69 (illustrated as being provided on a side surface of wireless handset 42 in FIG. 4B ) to facilitate the loading and downloading of information into memory 70 of the wireless handset 42 . I/O port 69 may comprise, for example, a data port, a Subscriber Identity Module (SIM) card slot and/or other types of ports or slots. Memory 70 of wireless handset 42 may store the MIN, programming and other operational information to implement the various features and aspects of the invention. Memory 70 may comprise a read-write memory device that has an independent power supply or whose contents will not be effected by power downs of ordinary duration. By way of non-limiting example, memory 70 may be implemented by a programmable Electronically Erasable Programmable Read Only Memory (EEPROM), a Complimentary Metal Oxide Semiconductor (CMOS) memory chip, or a conventional Random Access Memory (RAM) with an independent power supply.

[0124] As illustrated in the exemplary architecture arrangement of FIG. 4 A, antenna 62 may be connected to transceiver or tuner 63 , which in turn is connected to a control system 61 . Although transceiver 63 is illustrated as a single unit in FIG. 4A, a separate transmitter and receiver may also be provided to provide the functionality of transceiver 63 .

[0125] Control system 61 may be implemented as a microprocessor-based control system and may be programmed to carry out the various features of the invention. The programming of control system 61 may be carried out by any suitable combination or use of software, hardware and/or firmware. Control system 61 may control the various components of the wireless handset 42 to permit a user to send and receive calls and program the wireless handset. In addition, control system 61 may have access to memory 70 , in which the MIN and other programming information is stored, for directing operation of the wireless handset. A more detailed description of the various processes and functions of the operating features and modes of the invention is provided below with reference to the accompanying drawings.

[0126] As discussed above, the wireless handset of the present invention may be a full-featured wireless handset that is capable of operating within a wireless network (e.g., a cellular or PCS network) or in a direct handset-to-handset communication mode that functions independently of a wireless network. As such, the wireless handset of the present invention may be embodied as a full featured wireless handset capable of making traditional wireless calls and that has the additional functionality of enabling the handset to place direct calls to other handsets. Since direct calls do not access a wireless network, such calls will operate free of the wireless network and with little or no airtime charges (i.e., a monthly service or use charge may be charged to the user by the provider of the wireless handset). Direct calls that are placed without access to a network are referred to as “free calls” herein. According to an aspect of the present invention, the wireless handset may be provided with traditional or conventional wireless features, as well as the specific features and functionality of the present invention. Generally, the features of the wireless handset may be classified into the following categories: Traditional Wireless features; Free Call Control features; Find features; List Maintenance features; Conference Call features; Short Range Messaging features; and Accessory-Related features. Each of these features will be discussed in greater detail below.

[0127] If the wireless handset is embodied to provide Traditional Wireless features and call functionality, then the wireless handset may be implemented with traditional analog and/or digital wireless features. Such features may include: Caller ID; Caller ID Log; Short Message Service (SMS); Auto Answer; Choice of Alerts; Vibration Alert; Call Mute; Large, Scrollable Speed Dial List; Headset (with microphone accessory); and Computer Connectivity and Control. Any combination of these features, as well as additional features, may be embodied in the wireless handset to facilitate traditional analog and/or digital wireless connectivity. Of course, as discussed above, it is possible that the wireless handset be provided as a special purpose handset with only direct handset-to-handset functionality. In such a case, the above-described features may be eliminated or may be modified and provided to support direct handset communication.

[0128] As indicated above, calls made in a direct handset communication mode with the wireless handset are referred herein to as “free calls”, since such calls are made free of the wireless network and with little or no airtime charges. Free Call Control features may be provided to enhance the operation of the wireless handset when calls are placed directly from one handset to another. These features may encompass both call initiate and call receive features, and call in progress and alert features. Various call initiate feedback features may also be provided for Free Call Control. For example, when a user initiates a free call with the handset, the status or progress of the call may be indicated to the user through the use of predetermined messages and/or icons that are displayed on the handset and/or the generation of predetermined audible tones that are transmitted to the user through the speaker of the handset. For example, the display of the handset may indicate the name or ID of the handset to which the call is directed, and one or more icons or messages may be displayed on the handset to indicate the progress of the call (e.g., on-hook, off-hook, ringing, etc.). The status and progress of the initiated call may also be indicated to the user through the use of predetermined audible tones (e.g., dialing, ringing, busy, etc.). Messages may also be displayed on the handset to provide feedback to the user as to whether the offered call was not responded to or received by the called party. With such features, a user will be better equipped to handle and control direct handset calls with other users.

[0129] As indicated above, the handset of the present invention may also be provided with various Find features. These features may be provided to permit a user to determine all objects, including other handset users, that are within range or to determine if a specific handset or object is within range of the user. As further described below, the handset of the user may have a prestored find list of other handsets or objects that can be located with the Find features. A user may be given the option to locate a specific handset or object on the list or to initiate a general find function such that each of the handsets or objects on the list are queried to determine if they are within range. In order to maintain privacy, each handset or object may only respond to a query if they have the querying handset on a list and they are in range of the user. As a result, only handsets or objects that have given the querying handset permission to find them will respond to a find query.

[0130] The wireless handset of the present invention may also include a set of List Maintenance features. These features may be provided to permit a user to add and delete handsets or objects to one or more lists stored in the handset, such as a speed dialing list for initiating calls, a find list for locating other handsets or objects, and/or a privacy list for blocking find queries from specific handsets so that privacy may be maintained. With the List Maintenance features, a user may be permitted to add, delete and view each list stored in their handset. In accordance with an aspect of the present invention, a single list may be stored in each handset to function as a master list for all direct handset calls. In such a case, the master list may serve as a speed dial list, a find list and a privacy list. That is, the master list serves as a speed dial list when a direct handset call is initiated by a user, and also serves as a querying or find list when a find function is initiated by a user to locate all handsets or objects, or a specific handset or object that is within range. The List Maintenance features may also include a memorize feature which permits two handsets to update their respective master list, find list or privacy list with the ID of the other handset. The memorize feature may be activated when handsets are brought in close proximity to each other or their respective antennas are brought into contact, and users press a predetermined key or button within a short time window. As further discussed below, the memorize feature may also permit a user to memorize other objects, such as an accessory or device that is capable of being queried (such as a beeping clip or paging device) by activating the memorize function on the object in order to automatically add the object to the find list.

[0131] Other features that may be provided with the wireless handset include Conference Call features, Short Range Messaging features, and Accessory-Related features. The Conference Call features may permit “free call” conferencing between three handset users. The three-way conferencing may be enabled through time domain multiplexing and, as further described below, may utilize either a fixed controlled time slot or a variable controlled time slot to permit conferencing. The Short Range Messaging features may include features to permit short range messages to be sent directly from one handset to another handset when both handsets are idle or during a controlled time slot if the receiving handset is on a call. Further, Accessory-Related features may be provided to enhance the wireless handset of the present invention. For example, computer connectivity may be provided to enable downloading of lists and configuration data. Further, beeping clips or other paging devices may be provided that can be attached or secured to items (such as keys, wallets, tools, etc.) in order to facilitate finding those items through the Find features of the invention.

[0132] In order to implement the wireless handset of the present invention with such functionality, the wireless handset may be embodied with any suitable combination of hardware, software, logic and/or programmed code to perform the required functions. FIG. 5 illustrates a state transition diagram of the functionality that may be embedded in the wireless handset to provide direct handset-to-handset communication and free call capability. The exemplary state transition diagram of FIG. 5 illustrates the various states and trigger conditions to transition between each state. As discussed above, this functionality may be provided in a special purpose wireless handset or preferably may be embodied or bundled with a wireless handset which also has cellular or PCS capability. A wireless handset having both capabilities would provide a user with nearly ubiquitous coverage, either handset-to-handset or via a wireless network. In addition, such a wireless handset can also share circuitry to reduce costs over having two separate wireless handsets. For example, the handset-to-handset communication capability can use the same 10 Kbps data circuitry used in conventional analog cellular phones. The same voice processing circuitry could also be used, as well as the same housing, keypad, display, antenna, microphone, speaker, etc. by both functions.

[0133] Referring to FIG. 5 , when the wireless handset is powered or turned ON, the wireless handset may initialize and enter an Idle state. When in an Idle state, the wireless handset is waiting for a call. Calls may be placed in a direct handset-to-handset communication mode by dialing the assigned directory or telephone number of the handset. If a wireless handset is provided with dual functionality, the telephone number of the analog or digital handset (i.e., the MIN) may be the same number used for placing free calls to the wireless handset in a direct communication mode. In a direct communication mode, full duplex handset-to-handset call setup and call states are provided using frequency domain duplexing. In an Idle state, the receiver of the wireless handset may monitor a higher range of the duplex band to search for pages directed to its internally stored directory number or MIN. Free calls may be set up and handled over a non-cellular or unlicensed band. For example, direct handset-to-handset communication may be provided by utilizing a non-cellular, unlicensed band such as the 930 MHZ Industrial, Scientific and Medical band that is authorized under Part 15 of the FCC Rules.

[0134] As further discussed below with reference to FIGS. 6 A- 6 E, when a wireless handset is in an Idle state, the receiver of the handset may scan a predetermined set of frequencies (i.e., f ₁ , f ₂ , . . . f _N ). When the receiver or transceiver of the wireless handset tunes to a frequency, the handset may dwell long enough to measure the signal strength, obtain synchronization and decode a paging message, if available. If the signal strength is below a set threshold, or if no message is being sent, or a paging message directed to a different mobile station or wireless handset is decoded, the wireless handset may tune to the next frequency and repeat the process. If a paging message directed to the wireless handset is decoded, then the responding handset may send a page response on a lower range of the duplex band corresponding to the frequency to which the receiver is tuned. While paging, the originating wireless handset receiver listens for a page response on the lower associated duplex frequency (Paging state in FIG. 5 ). If the receiver decodes the response without error, then the wireless handset will switch to a voice mode on the same duplex frequency pair and enter a Conversation state. This is illustrated in FIG. 5 by condition f (page received and user answers). If the page response is not decoded after a predetermined number of attempts (i.e., M page attempts), the originating handset may provide a reorder alert (e.g., a reorder tone in the speaker or earpiece) and not enter into a Conversation state. “M” may be selected to ensure that a handset in the Idle mode will scan and decode the frequency at least once. Under this condition, the originating wireless handset which sent the paging message will return to an Idle state from a Paging state. This transition is illustrated in FIG. 5 by condition c (no page response received). In an Idle state, the paged wireless handset may respond a predetermined number of times (e.g., L times) when paged by an originating wireless handset. “L” may be greater than one to increase the reliability that the message will be received without errors. The paged wireless handset will then switch to a voice mode and enter a Conversation state when the user indicates that the call should be answered (i.e., a user may press an answer key to indicate that the call should be received). This transition is indicated in FIG. 5 by condition f (page received and user answers). Otherwise, if the user does not answer, the paged wireless handset will eventually time out and stay in an Idle state.

[0135] FIGS. 6 A- 6 E are exemplary flowcharts of the various processes and operations that may be performed by a wireless handset of the invention when operating in an Idle state and responding to various messages from other handsets. According to an aspect of the present invention, N frequency pairs may be assigned to the wireless handset. The higher frequency associated with the duplex channel “i” is designated as F _hi . Further, in the illustrated embodiment, the lower frequency is designated as F _li . Essentially, up to N simultaneous calls can be supported assuming adequate adjacent channel selectively in the wireless handsets. FIG. 6A illustrates a sequential scan of the N channels. Alternative arrangements, however, may be provided. For example, a quick search based on signal strength could be implemented. In such a case, only channels exceeding a predetermined or programmed signal strength threshold would be evaluated for synchronization and paging messages. Further, the signal strength ranking would be updated periodically.

[0136] In the exemplary embodiment of FIG. 6 A, when a wireless handset enters an Idle state, the receiver of the wireless handset is switched to a predetermined higher band of the duplex pass band (see step S. 2 ). Further, at step S. 2 , the transmitter is switched to a predetermined lower band of the duplex pass band. Thereafter, at step S. 4 , a counter i is set to 1. At step S. 6 , the receiver of the wireless handset is tuned to the high frequency F _hi . After tuning the receiver to the frequency F _hi , the handset waits for a synchronization signal.

[0137] At step S. 8 , it is determined whether a synchronizing signal is received. If synchronization is received, then logic flow proceeds to step S. 12 . Otherwise, at step S. 10 , the counter i is modified according to the following formula:

i =( i+ 1) modN.

[0138] Following step S. 10 , logic flow returns to step S. 6 , where the receiver of the handset is returned to the next high frequency F _hi .

[0139] At step S. 12 , the wireless handset determines whether a page message has been received. If a page message is not received within a predetermined period of time, then logic flow proceeds to step S. 16 , where the handset determines whether another type of message has been received. Otherwise, at step S. 14 , the called party directory number DNr is decoded by the receiver based on the page message that is received and it is determined whether the directory number DNp stored in the wireless handset is the same as or corresponds to the called party directory number DNr.

[0140] If it is determined at step S. 14 that DNr-DNp, then at step S. 1600 (see FIG. 6B ) the transmitter of the wireless handset is tuned to the lower frequency F _li . Otherwise, logic flows back to step S. 10 , so that i is modified and the receiver is tuned to a different high frequency.

[0141] As shown in FIG. 6 B, following step S. 1600 , the receiving wireless handset sends a page response message at step S. 1618 . In accordance with an aspect of the present invention, the page response message may be sent back to the originating wireless handset repetitively to ensure receipt of the same. For this purpose, the page response message may be sent a predetermined number of times (e.g., L times). Thereafter at step S. 1620 , the receiving wireless handset may activate an alerter of the receiving handset so as to provide an alert indication to the user of the incoming call. The alert indication provided by the alerter may comprise an alerting signal or tone (such as a ringing signal or tone) or activation of a vibration mechanism to cause the wireless handset to vibrate. Other alerting indications may be provided and may be activated by the user.

[0142] As further shown in FIG. 6 B, at step S. 1622 , the wireless handset determines whether the user has indicated to answer the incoming call in response to the generation of the alert indication. In accordance with an aspect of the present invention, the user may be given a predetermined amount of time (i.e., T _alert seconds) to respond to and to indicate whether a call should be answered. If the wireless handset user indicates to answer the call within the predetermined time (e.g., by pressing an answer or talk button on the wireless handset), the wireless handset may switch to a voice mode at step S. 1624 and enter into a Conversation state to provide full duplex communication between the wireless handsets. Otherwise, at step S. 1626 , the wireless handset may display an indication to the wireless handset user that the call was received but not answered and, thereafter, enter into an Idle state.

[0143] Referring again to FIG. 6 A, if it is determined that a page message was not received at step S. 12 , then at step S. 16 the handset will determine whether a find message has been received from another handset. As disclosed herein, the wireless handsets of the present invention may include a find feature that permits a handset to locate objects, including other wireless handsets, that are within range. If a find message has been received at step S. 16 , then logic flow proceeds to step S. 18 . Otherwise, if a find message has not been received at step S. 16 , the handset proceeds to step S. 20 to determine if another type of message has been received.

[0144] At step S. 18 , the called party directory number DNr is decoded by the receiver of the handset based on the find message that is received and it is determined whether the directory number DNp stored in the wireless handset is the same as or corresponds to the called party directory number DNr. If it is determined at step S. 18 that DNr=DNp, then at step S. 1630 (see FIG. 6C ) the wireless handset will determine whether the requesting handset that sent the find message is on its Find list. Otherwise, logic flows back to step S. 10 , so that i is modified and the receiver is tuned to a different high frequency.

[0145] As illustrated in FIG. 6 C, at step S. 1630 it is determined whether the requesting DN is on the Find list of the handset. The determination at step S. 1630 may be made by comparing the directory number DN or ID of the requesting handset provided in the find message that was received with the entries in the Find list of the wireless handset. As further described below, this determination may be made in order to maintain privacy and limit the find capability to only authorized handset users. If the requesting DN is on the Find list, then at step S. 1632 the transmitter of the wireless handset is tuned to the lower frequency F _li . Otherwise, the find request may be ignored and the handset may enter back into the Idle state following step S. 1630

[0146] After tuning the transmitter at step S. 1632 , the receiving wireless handset sends a found response message to the requesting handset at step S. 1634 . In accordance with an aspect of the present invention, the found response message may be sent back to the requesting wireless handset repetitively to ensure receipt of the same. For this purpose, the found response message may be sent a predetermined number of times (e.g., L times). Thereafter, at step S. 1636 , the receiving wireless handset may activate a found alerter of the receiving handset so as to provide an alert indication to the user of the find request. The alert indication provided by the alerter may comprise an alerting signal or tone (such as a ringing signal or tone) and/or a message that is displayed on the handset. In addition, at step S. 1638 , the receiving handset may update a Found list so as to indicate that the requesting handset is within range. Following step S. 1638 , the wireless handset may enter an Idle state.

[0147] Referring once again to FIG. 6 A, if it is determined that a find message was not received at step S. 16 , then at step S. 18 the handset will determine whether a memorize message has been received from another handset. As disclosed herein, the wireless handsets of the present invention may include a memorize feature that permits handsets to exchange handset information, including handset DN or ID, and corresponding name. If a memorize message has been received at step S. 20 , then logic flow proceeds to step S. 22 . Otherwise, if a memorize message has not been received at step S. 20 , the handset proceeds to step S. 24 to determine if another type of message has been received.

[0148] At step S. 22 , the called party directory number DNr is decoded by the receiver of the handset based on the memorize message that is received and it is determined whether the directory number DNp stored in the wireless handset is the same as or corresponds to the called party directory number DNr. If it is determined at step S. 22 that DNr-DNp, then at step S. 1640 (see FIG. 6D ) the wireless handset will set the value of a timer i to zero. Otherwise, logic flows back to step S. 10 , so that i is modified and the receiver is tuned to a different high frequency.

[0149] As illustrated in FIG. 6 D, at step S. 1640 the value of a timer i is initialized and set to zero. Thereafter, the handset determines at step S. 1642 whether the user has responded by pressing an appropriate key or button on the handset (e.g., a memorize key) so as to activate the memorize feature. In accordance with an embodiment of the memorize feature described herein, the memorize feature must be activated by both handsets within a predetermined time window to permit the exchange of information to occur. If the memorize feature is not activated at step S. 1642 , then the handset will increment the timer i by one at step S. 1644 and determine at step S. 1646 whether the value of the timer i is greater than or equal to a predetermined time limit i _max . If the value of the timer i _max , is less than i _max , then logic flow loops back to step S. 1642 to again determine whether the memorize feature has been activated. Otherwise, if the timer i is not less than i _max , then the time limit for activating the memorize feature has been exceeded and the memorize request is ignored, with the handset entering the Idle state.

[0150] If the user responds and activates the memorize feature at step S. 1642 , then at step S. 1648 the transmitter of the wireless handset is tuned to the lower frequency F _li . Further, after tuning the transmitter at step S. 1648 , the wireless handset sends a memorize response message to the requesting handset at step S. 1650 . In accordance with an aspect of the present invention, the response message may be sent back to the requesting wireless handset repetitively to ensure receipt of the same. For this purpose, the memorize response message may be sent a predetermined number of times (e.g., L times). Thereafter, at step S. 1652 , the receiving wireless handset may activate a memorize success alerter so as to provide an indication to the user of that the memorize feature has been invoked with the requesting handset. The alert indication provided by the alerter may comprise an alerting signal or tone (such as a ringing signal or tone) and/or a message that is displayed on the handset. Following the successful exchange handset information, at step S. 1654 the handset may update the speed dial and/or find lists of the handset with the handset information of the handset that sent the memory request. Following step S. 1654 , the wireless handset may enter an Idle state.

[0151] As shown in FIG. 6 A, if it is determined that a memorize message was not received at step S. 20 , then at step S. 24 the handset will determine whether a short range message has been received from another handset. As disclosed herein, the wireless handsets of the present invention may include a short range messaging feature that permits handsets to send and receive short range messages. If a short range message has been received at step S. 24 , then logic flow proceeds to step S. 26 . Otherwise, if a memorize message has not been received at step S. 24 , logic flow loops back to step S. 10 , so that i is modified and the receiver is tuned to a different high frequency.

[0152] At step S. 26 , the called party directory number DNr is decoded by the receiver of the handset based on the short range message that is received and it is determined whether the directory number DNp stored in the wireless handset is the same as or corresponds to the called party directory number DNr. If it is determined at step S. 26 that DNr-DNp, then at step S. 1660 (see FIG. 6E ) the wireless handset will tune the transmitter of the handset to the lower frequency F _li . Otherwise, logic flows back to step S. 10 , so that i is modified and the receiver is tuned to a different high frequency.

[0153] At step S. 1660 , the transmitter of the wireless handset is tuned to the lower frequency F _li . As illustrated in FIG. 6 E, after tuning the transmitter at step S. 1660 , the wireless handset sends a short range message response message to the transmitting handset at step S. 1662 to confirm receipt of the short range message. In accordance with an aspect of the present invention, the response message may be sent back to the originating wireless handset repetitively to ensure receipt of the same. For this purpose, the short range message response message may be sent a predetermined number of times (e.g., L times). Thereafter, at step S. 1664 , the receiving wireless handset may activate an alerter so as to provide an indication to the user of that a short range message has been received. The alert indication provided by the alerter may comprise an alerting signal or tone (such as a ringing signal or tone) and/or a message (e.g., “Short Range Message Received”) that is displayed on the handset. Following step S. 1664 , the handset may decode the short range message at step S. 1668 and, display and/or store the decoded message with the handset. The decision to display or store the message may be optional and/or controlled by the user. Following step S. 1668 , the wireless handset may enter an Idle state.

[0154] As illustrated in FIG. 5 , the wireless handset will transition between an Idle state and a Conversation state under condition f; that is, when a page message is received and the user answers, the wireless handset will transition from an Idle state to a Conversation state. In a Conversation state, the wireless handset will operate in a voice mode to provide full duplex communication between the wireless handsets. The wireless handset may return to an Idle state under various conditions. For example, as further illustrated in FIG. 5 , the wireless handset will return to an Idle state from a Conversation state under condition d (when the user indicates that the call is to be ended by pressing, for example, an end key). A transition from a Conversation state to an Idle state may also occur where a supervisory signal is lost (this is indicated by condition e in FIG. 5 ).

[0155] When an originating wireless handset initiates a call, the originating wireless handset will transition from an Idle state to a Paging state. The transition from an Idle state to the Paging state occurs under condition a, when a user indicates to initiate or start a free call by pressing a send or free key on the wireless handset. In the Paging state, the wireless handset essentially functions in a state where it pages another wireless handset based on the directory number or telephone number entered by the user. Normally, the Paging state is entered from the Idle state according to the conditions described above. More specifically, the trigger to enter the Paging state is when a valid handset or object is chosen and the appropriate key (such as a send button or free call button) is pressed by the user. As illustrated in FIG. 5 , the wireless handset may transition back to the Idle state under various conditions. Condition b and condition c in FIG. 5 illustrate two such examples. In condition b, the wireless handset will transition from the Paging state to the Idle state when the called party does not answer the call request. Additionally, the transition from the Paging state to the Idle state will occur under condition c, when no page response has been received by the originating wireless handset. If a page is successfully received and the call request is answered by the called party, then the wireless handset will transition from a Paging state to the Conversation state. This condition is depicted in FIG. 5 by condition h (i.e., page response received and called party answers).

[0156] As described above, in a Paging state, the wireless handset pages another wireless handset with the appropriate directory number or phone number. FIGS. 7A and 7B illustrate an exemplary flowchart of the various processes and operations that may be carried out during a Paging state. Generally, in a Paging state, the wireless handset swaps the transmit and receive frequencies so that other wireless handsets in an Idle state can listen for pages. If a page is responded to and the called party enters the Conversation state, the call is set up.

[0157] Prior to selecting a channel, the wireless handset may check the channel for possible interference based on, for example, signal strength. The exemplary flowchart of FIGS. 7A and 7B illustrate that such checks may be made until a channel is located that has a signal strength less than or equal to a predetermined threshold level, THR _rssi . As an additional measure, the wireless handset may be configured such that it will terminate analysis of channels for signal strength after a predetermined period of time and provide a warning tone to the user to indicate that no channels are available.

[0158] More particularly, as illustrated in FIG. 7 A, when entering a Paging state, a wireless handset will first prepare or gather the handset phone number at step S. 30 . The called party digits may correspond to the directory or phone number of the wireless handset of the called party. At step S. 32 , the wireless handset will then switch the receiver to the lower frequency band of the duplex pass band and will switch the transmitter to the higher frequency band. At step S. 34 , the handset will initialize a counter i to 1. Then, at step S. 36 , the receiver of the handset will be set to the low frequency F _li and the transmitter will be tuned to the higher frequency F _hi .

[0159] After tuning the receiver and transmitter, the wireless handset will determine at step S. 38 whether there is interference in the channel. Interference may be analyzed by determining whether the signal strength of the channel is not greater than a predetermined threshold. For example, at step S. 38 , the wireless handset may determine whether the received signal strength of the channel is less than or equal to a threshold level THR _rssi . If it is not, then at step S. 40 , the count i may be modified according to the following equation:

i =( i+ 1) modN

[0160] After i is reset, logic flow proceeds back to step S. 36 so that another channel is tuned to and analyzed for interference.

[0161] If the signal strength of the channel is determined to be appropriate, then at step S. 42 a counter m is initialized and set to 0. Thereafter at step S. 44 (see FIG. 7B ), a synchronization signal is sent by the wireless handset, as well as a paging message at step S. 46 . The paging message may contain the directory phone number of the called party, as well as the calling party name or number for caller ID purposes. If caller ID is not equipped in the system, then sending of the calling party name and number is not necessary in or processed from the paging message.

[0162] At step S. 48 , it is determined whether a page response message has been received indicating that the called party's wireless handset is within range. If no page response message is received, then at step S. 50 the counter m is incremented by one and at step S. 52 it is determined whether m has exceeded a predetermined limit L. If m is less than or equal to the predetermined limit L, then logic flow proceeds back to step S. 44 so that a synchronizing signal and the paging message may be resent. Otherwise, at step S. 54 , a reorder indication is provided to the user to indicate that the call request was unsuccessful and that the call request should be placed at another time. Following step S. 54 , the wireless handset transitions from the Paging state back to the Idle state.

[0163] As illustrated in FIG. 7 B, if a page response message is received at step S. 48 , then at step S. 56 , a ring back tone or another form of signal is provided to the user to indicate that the call request was received. In accordance with conventional wireless handsets, the ring back tone may be an audible tone that is provided at the earpiece of the speaker of the wireless handset.

[0164] At step S. 58 , the originating mobile station determines whether the called party has answered within a predetermined amount of time. For example, a predetermined amount of time (designated as T _alert seconds in FIG. 7B ) may be designated to permit the called party to answer within a certain number of seconds (for example, 20-30 seconds). If it is determined at step S. 58 that the called party has not answered within the predetermined period, then the originating phone may return to an Idle state. Otherwise, if the called party answers within the predetermined time, then the phone may enter into a Conversation state to permit full duplex voice communication to be carried out between the parties.

[0165] FIG. 8 illustrates an exemplary flowchart of the various processes and operations that may be carried out by a mobile station when it is in a Conversation state. As indicated in FIG. 5 , the mobile handset may transition into the Conversation state from either an Idle state (under condition f) or from a Paging state (under condition h). A transition from an Idle state to a Conversation state will occur under condition f, when a page has been received and the user answers. A transition from a Paging state to a Conversation state will occur under condition h, when a page response is received and the called party answers. Therefore, both the originating and answering mobile station may enter into a Conversation state. The originating handset may transmit on a frequency that the answering mobile station is tuned to receive and vice versa, in accordance with the previous descriptions.

[0166] At step S. 60 , the wireless handset that has entered into a conversation state switches circuitry to transmit and receive voice communication signals. Thereafter, at step S. 62 , a supervisory signal is sent. The supervisory signal may be based on the supervisory audio tone (SAT) encoding/decoding circuitry employed by cellular phones. At step S. 64 , the mobile station then initializes a counter t _s to 0. Thereafter, the supervisory signal is decoded at step S. 66 .

[0167] At step S. 68 , the mobile station determines whether the supervisory signal is still present. If the supervisory signal is still present, then the received audio is unmuted at the handset's earpiece at step S. 69 and the mobile handset determines whether an end key is pressed by the user to indicate end of the conversation at step S. 78 . If the end key is pressed by the user or another appropriate key is pressed by the user to indicate end of the conversation or call, then at step S. 80 the handset switches back to the data circuitry and stops sending the supervisory signal. Subsequent to step S. 80 , the mobile handset returns to the Idle state. If, at step S. 78 , it is determined that the end key has not been pressed by the user, then logic flow proceeds back to step S. 64 where the counter t _s is initialized to 0 once again.

[0168] If, at step S. 68 , it is determined that the supervisory signal is not present, then at step S. 70 the received audio is muted at the handset's earpiece and at step S. 72 t _s is incremented by 1. Thereafter, at step S. 74 , it is determined whether a corrupted signal is received for a time period that exceeds a predetermined interval or time. That is, at step S. 74 , it is determined whether t _s is greater than or equal to the maximum interval or time T _Hi . If t _s is greater than or equal to T _Hi then at step S. 76 a reorder indicator or tone is provided to the user to indicate that the signal has been lost. Thereafter, at step S. 80 , the mobile station switches back to the data circuitry and stops sending the supervisory signal. This permits the wireless handset to transition back to the Idle sta