Patent Application
20060148535
This invention relates generally to call setup on a wireless mobile dispatch network.
Battery conservation on mobile units or devices is a major concern in wireless communication systems. As a way to preserve battery life, these mobile units will become inactive (e.g., dormant) on their radio frequency (“RF”) channels after a short period of inactivity of usage for data services, which is generally about 30 to 60 seconds. As a result of the mobile units being dormant and prior to when a dispatch call function can be enabled, the originator mobile unit (e.g., the mobile unit originating the dispatch call) and the target mobile unit (e.g., the mobile unit with which the originator mobile unit sets up the dispatch call) must transition from the inactive state to the active state (e.g., using the RF resources) as part of a call setup. In other words, once a mobile unit is in the active state, only then can an RF channel be established, thereby enabling the mobile unit to transmit and/or receive data via the channel.
One problem is that for a typical wireless mobile network, the time required to transition the originator mobile unit from the dormant state to the active state can be as much as 3 seconds or more. This transition time requirement applies to both the originator mobile unit and the target mobile unit. In addition, more time is usually needed to page the mobile device. Current call setup systems, however, do not compensate for required transmission time over the air and call processing time. Thus, adding these time delays, the total time required to effectuate a dispatch call between the originator mobile unit and the target unit can be 10 seconds or greater. With such long latency start times, the advantage of the dispatch call service as an instant communication is greatly diminished.
In order to shorten call setup time of dispatch calls, one prior method takes prospective action on the originator mobile unit to wake up the originator mobile and the target mobile unit. After the originator mobile unit has transitioned from the dormant state to the active state and a target mobile unit has been selected, a wakeup packet is sent to the target mobile unit to initiate transition of the target mobile unit from dormant to active state. As a result, the time needed to complete a call setup of the dispatch call is reduced, since the originator mobile and the target mobile unit are awakened from the dormant state prior to call setup initiation. Although this method reduces setup delay time, it wastes RF resources unnecessarily because RF resources are being utilized after premature trigger functions that require an unneeded wait time, such as while the user is selecting the target mobile unit, which may be a long time before the user actually makes a target selection.
The above needs are at least partially met through provision of the dispatch call setup process described in the following detailed description, particularly when studied in conjunction with the drawings, wherein:
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of various embodiments of the present invention. Also, common and well-understood elements that are useful or necessary in a commercially feasible embodiment are typically not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.
Generally speaking, pursuant to these various embodiments, a dispatch call setup process has been provided, which triggers a short data burst packet that includes an identity of a target mobile unit to be sent to the target mobile unit responsive to the selection of the target mobile unit. According to various embodiments, in response to the short data burst packet, the target mobile unit is able to immediately transition from a dormant state to an active state, which results in an RF link between the originator mobile unit and the target mobile unit being established prior to the initiation of the communication channel. According to one embodiment, the originator mobile unit also transitions from the dormant state to the active state responsive to the sending of the short data burst packet in order to improve the start delay time. According to another embodiment, the originator mobile unit transitions from the dormant station to the active state in response to the initiation of the call setup function.
According to another embodiment, the communication channel is based on a Code Division Multiple Access system. Although not necessarily being system-specific, the short data burst packet can be a dummy packet or a packet with configuration information needed for the call setup function. In various embodiments, the call setup function relates to any one or more calls of a push-to-talk call, a telephone call, multimedia session call, or a Voice over Internet Protocol (“VoIP”) call. Through these various teachings, the call setup delay time is reduced with a minimum RF cost. For example, unlike the prior art, the RF resources are not wasted while the user is selecting from the address book, which can be a long wait period. Moreover, because the short data burst packet provides a very small payload that can be quickly sent to the network, the time needed for lengthy traffic channel establishment procedures is comparably reduced. Specifically, the waste of RF resources is reduced compared to the standard originator speculation. On the other hand, when the present embodiments are combined with the originator speculation, the performance gain is also improved with various teachings described.
Referring now to the drawings, and in particular to
Referring to the exemplary dispatch call network shown in
Referring to
Users, through the use of the user interface 34, are able to input and output various functions and selections. For example, a user of the originator mobile unit 16 can easily select the target mobile unit 18 via a target mobile unit selector 42 of the input device 36, which triggers a short data burst unit 44 to send a short data burst packet out to the network via the transmitter. In one embodiment, responsive to the short data burst packet being sent onto the network, the mobile unit 20 is transitioned from the dormant state to the active state by a sleep mode controller 46. After the mobile unit 20 is in active state, a call initiation unit 48 initiates a call setup function in order to establish a communication channel between the originator mobile unit and the target mobile unit. The inner workings of the mobile unit 20 are readily appreciated by one skilled in the art.
Turning now to
In this embodiment with speculation, both the origin mobile unit and the target mobile unit are awakened with the selection of the trigger function. Specifically, as soon as the target mobile unit 18 is selected 54 by the origin mobile unit 16, a short data burst packet is sent 58 to the call server 12, which is in turn forwarded 60 to the target mobile unit. As a result, the target mobile unit is awakened from the dormant state during the wake up period 64 such that it can be sent the wake up short data burst packet. Note that the short data burst packet is sent at the selection of the target mobile unit on the origin mobile unit in both implementations with and without speculation.
Once the short data burst packet has been sent and the origin wake up period has elapsed, the origin mobile unit 16 initiates 66 the call setup function to begin the call setup procedure with the target mobile unit 18. In particular, a call setup request is sent 68 to the call server 12, which is again forwarded 70 to the target mobile unit 18. Since the target mobile unit 16 was previously transitioned from the dormant state to the active state with the sending of the short data burst packet, the target mobile unit 16 can quickly respond 72 with a call accept message to the call server 12. The call server 12 accordingly forwards 74 the call accept message to the origin mobile unit 16, which completes 76 the call setup for the implementation with speculation. Note that with the speculation implementation, the exchange between the origin mobile unit 16 and the target mobile unit 18 is fairly instantaneous. Since the wake up delays have already occurred, the only delays that are incurred on the call setup 68, 70 and accept messages 72, 74 are the normal transport delays associated with the packet data network.
In the implementation without the speculation, the origin mobile unit does not begin its wakeup period 78 until the call setup function has been initiated. In this case, the origin mobile unit 16 transitions from the dormant to the active state when the call setup is initiated, meaning there is a lag time for the transition before the call setup request can be sent 80 to the call server 12. In this implementation, there is extra delay in the startup time as compared to the implementation with speculation, because the origin mobile unit does not begin its transition until the call setup function has been initiated. The origin mobile unit, however, must wait until the transition is complete before it can send 80 the call setup request to the call server 12. When this is done, the call server 12 accordingly forwards 82 the call setup request to the target mobile unit 18 that has been active and ready. The target mobile unit quickly responds 84 to the call setup request with a call accept message without the transition delay time of the target mobile. The call server accordingly sends 86 the call accept message to the origin mobile unit, and the call setup process is complete 88. As shown, there is a definite startup delay time difference between the implementation with speculation and without speculation in that the speculation implementation is faster.
While the implementation with speculation provides for fast startup time, more RF resources are used in these embodiments (e.g., more time is spent in an active RF channel state). In contrast, less RF resources are being used for the implementation without speculation, but the tradeoff is longer delay of the startup time. Depending on the network and system, one may be more preferable than the other. Nonetheless, these various implementations are contemplated and readily appreciated by one skilled in the art, and they are within the scope of the various teachings shown.
Turning now to
With these various teachings shown, a novel call setup technique has been provided. As a result of the various teachings shown, the call setup delay time is reduced with minimum RF cost. Instead of wasting the RF resources on premature speculation trigger functions, which occurred, for example, while the user selects from the address book, the various embodiments provide a way to wake up the target mobile unit with the short data burst packet and the originator mobile unit with the selection of the target mobile unit. Since the short data burst packet provides a very small payload that can be quickly sent to the network, the delay time of the lengthy traffic channel establishment procedures are reduced. Additionally, the transition time of the mobile units is shortened and any waste of the RF resources is minimized.
Those skilled in the art will recognize that a wide variety of modifications, alterations, and combinations can be made with respect to the above described embodiments without departing from the spirit and scope of the invention, and that such modifications, alterations, and combinations are to be viewed as being within the ambit of the inventive concept.
