System and method to dynamically manage a talk group signaling type

A transmission capability of a mobile station that requests to be affiliated with a talk group is received. It is then determined whether to alter a current transmission mode of the talk group based at least in part upon the transmission capability of the mobile station, the current transmission mode of the talk group, and the transmission mode of one or more radio frequency (RF) sites associated with the talk group.

FIELD OF THE INVENTION

The field of the invention relates to conducting communications in networks and, more specifically, to determining a communication mode of a talk group within these networks.

BACKGROUND OF THE INVENTION

Mobile stations operate in various operating modes, use different technologies, and utilize different protocols as they move across different networks or across the same network. For example, mobile stations may operate according to frequency division multiple access (FDMA) or time division multiple access (TDMA) technologies. In other examples, mobile stations may operate according to full rate or half rate vocoder technologies.

These different modes may determine different operating characteristics of the mobile station. In one example, the operating mode determines whether the mobile station utilizes full rate vocoder capabilities, or, alternatively, both full and half rate vocoder capabilities. Being able to operate the mobile station according to different modes allows the mobile station to operate more efficiently and effectively as it moves across different operational environments.

Unfortunately, situations exist where it is difficult or impossible to operate mobile stations according to multiple types of technologies or protocols. For example, when full rate capable mobile stations attempt to affiliate with a half-rate vocoder talk group, the full rate vocoder capable mobile station will not be able to communicate with the talk group since the talk group uses half-rate vocoder technology signaling and full rate vocoder capable mobile stations cannot utilize half-rate vocoder signaling. Consequently, the mobile station is left without communication capabilities.

In another example, when a half-rate vocoder capable mobile station roams to a radio frequency (RF) site that does not support half-rate vocoder signaling (e.g., legacy full rate vocoder signaling), the mobile station will not be able to operate until the user changes to a talk group that supports full rate vocoder signaling. As with the previous example, the user is left without communication capabilities. Because of the above-mentioned problems, it is difficult for users to operate mobile stations in various operating modes, using different technologies, and according to different protocols as the user moves across different networks or across the same network.

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 and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. It will further be appreciated that certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. It will also be understood that the terms and expressions used herein have the ordinary meaning as is accorded to such terms and expressions with respect to their corresponding respective areas of inquiry and study except where specific meanings have otherwise been set forth herein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A system and method is provided to determine the transmission mode of a talk group as mobile stations roam between radio frequency (RF) sites or affiliate with the talk group. The approaches provided herein allow the user to communicate from their mobile station even as they roam through networks, encounter RF sites, and select talk groups that are operating according to various transmission modes.

In many of these embodiments, a mobile station (having a transmission capability) registers at a network entity such as a zone controller via an RF site. When the mobile station then requests to be affiliated with a talk group, the network entity then determines whether to alter the current transmission mode of a talk group based upon the transmission capability of the mobile station, the current transmission mode of the talk group, and the transmission capability of one or more radio frequency (RF) sites associated with the talk group.

The transmission capability of the mobile station and the transmission mode of the talk group may take a number of different forms. For example, the modes may provide a full rate vocoder-only capability or a full and half-rate vocoder capability. In other examples, the modes may relate to different technologies (e.g., FDMA and TDMA).

As mentioned, the determination of whether to alter the operating mode of the talk group may depend upon various factors or combinations of factors. For instance, the determination may depend upon a comparison between a first number of mobile stations operating at the talk group according to a first mode to a second number of mobile stations operating according to a second mode.

The RF site capabilities may also be used to determine the transmission mode of the talk group. For example, if there is a mobile station operating at an RF site that is only capable of full rate vocoder operation, the talk group may operate in the full vocoder mode.

In another example, a talk group call is active in a first transmission mode (e.g., TDMA or half-rate) and a second mobile station that is only capable of operating in a second transmission mode (FDMA or full rate) affiliates with the same talk group during the active call. When this occurs, the active call is allowed to continue in the current transmission mode (TDMA or half-rate) without the affiliating mobile station participating in the call. However, once the call ends, subsequent transmissions, until the talk group transmission mode is reevaluated, may occur in a second transmission mode (e.g., FDMA or full rate vocoder) to allow all mobile stations in the talk group to participate in the call.

In some of these embodiments, a user preference may also be obtained to dynamically determine whether to alter the talk group mode. For example, the user preference may be FDMA-only, full rate vocoder only, TDMA-only, half-rate vocoder only, or dynamic. Other examples of user preferences are possible.

Thus, approaches are provided that allow users to operate their mobile stations according to multiple modes and traverse networks without losing communications. These approaches are efficient to use and enhance user satisfaction with their experience within the network.

Referring now toFIG. 1, one example of a system for dynamically adjusting the transmission mode of a talk group is described. A first mobile station102(MS A), a second mobile station104(MS B), and a third mobile station106(MS C) operate within a network that includes a first RF communication site110(RF site A) and a second RF communication site112(RF site B).

The mobile stations102,104, and106may include a variety of different mobile communication devices. For example, the mobile stations102,104, and106may be two-way radios, cellular phones, pagers, personal digital assistants, or personal computers. Additionally, the mobile stations102,104, and106and RF sites110and112may operate according to any communication protocol or technology. For example, the mobile stations102,104, and106and RF sites110and112may operate in a frequency division multiple access (FDMA) mode, time division multiple access (TDMA) mode (e.g., 2 to 1 TDMA, 4 to 1 TDMA), full rate vocoder mode, half-rate vocoder mode, or combinations of these modes. Other examples of mobile stations and operating modes for these mobile stations are possible.

The first and second RF sites110and112are coupled to a zone controller108. The zone controller108determines the transmission mode of a talk group114based upon a variety of factors. For example, the zone controller108may determine the transmission mode of a talk group based upon the transmission capabilities of mobile station, the current talk group mode, the transmission mode of one or more RF sites, and/or user preferences. Other factors may also be considered when determining the mode of the talk group.

The zone controller108maintains information concerning the talk group114, for example, in a memory device that may or may not be co-located at the zone controller108. In this example, the talk group114includes a first mobile station102(MS A) and a second mobile station104(MS B). This talk group114has an associated transmission mode, for example, FDMA mode, TDMA mode (e.g., 2 to 1 TDMA, 4 to 1 TDMA), full rate vocoder mode, half-rate vocoder mode, or some combination of these modes.

In one example of the operation of the system ofFIG. 1, a third mobile station106(MS C), which has previously registered its transmission capabilities, attempts to affiliate with the talk group114. As mentioned, the talk group114already has two current members (MS A and MS B). When attempting to affiliate, this new mobile station106(MS C) communicates to the zone controller108indicating the talk group it will monitor. The zone controller108receives the information, for example via the RF site110(RF site A) and determines whether to alter the current transmission mode of the talk group114. The determination may be based upon the transmission capability of the mobile station106, the current transmission mode of the talk group, the transmission mode of any of the RF sites110and112associated with the talk group114, or user preference information.

In one example of determining whether to make an adjustment, the determination may be based upon whether a first number of mobile stations operating at the talk group according to a first mode exceeds a second number of mobile stations operating according to a second mode. Alternatively, other combinations of decision making can be used such as one or more mobile stations operating in legacy mode (e.g., full rate vocoder) and any number of mobile stations operating in other modes (e.g., both full and half rate vocoder), selecting the legacy mode of operation.

In another example, a talk group call is active in a first transmission mode (e.g., TDMA or half-rate) and the mobile station106that is only capable of operating in a second transmission mode (FDMA or full rate) affiliates with the talk group114during the active call. When this occurs, the active a call is allowed to continue in the current transmission mode (TDMA or half-rate) without the affiliating mobile station participating in the call. However, once the call ends, subsequent transmissions, until the talk group transmission mode is reevaluated, may occur in the second transmission mode (e.g., FDMA or full rate vocoder) to allow the mobile stations102and104and106in the talk group114to participate in the call.

The user may also select preferences for the current transmission mode of the talk group114. For example, the user may select the modes of FDMA-only (the talk group always operates in FDMA mode regardless of the capabilities of the mobile stations), full rate vocoder only (the talk group always operates in full rate vocoder mode regardless of the capabilities of the mobile stations), TDMA-only (the talk group operates in TDMA mode regardless of the capabilities of the mobile stations), half-rate vocoder only (the talk group operates in half-rate vocoder mode regardless of the capabilities of the mobile stations), and dynamic (the capabilities of the mobile stations and the RF site determine the transmission mode of the talk group). The user may enter these preferences in a variety of different ways, for example, from the mobile station or from a dedicated terminal coupled to the zone controller108.

In making the determination to alter the mode of the talk group114, different weights or priorities may be assigned to the different factors considered. For example, the transmission mode of a mobile station may take highest priority. In another example, the preference of the user may take the highest priority.

Referring now toFIG. 2, one example of an approach for dynamically adjusting the operating mode of a talk group is described. At step202, the mobile station (MS) sends a registration message to an RF site. The mobile station then affiliates with the talk group. The registration message includes the transmission capability of the mobile station (MS).

An example of this message is a unit registration message sent upon power up of the mobile station. Alternatively, a user may pre-program the capability at the site or the Zone Controller or the site may determine the mode from other information received from the mobile station (MS). At step204, the registration message is relayed from the RF site to the zone controller.

At step206, the RF site sends its transmission capability to the zone controller. Alternatively, the zone controller may maintain information concerning the operating mode of the RF site or the zone controller may determine the transmission mode from other information received from the RF site.

The zone controller tracks the talk group mode based upon several factors (e.g., transmission capability of mobile station affiliated, transmission capability of RF sites with affiliated mobile stations, user preference). At step208, the current mode of the talk group is forwarded to the zone controller. The information concerning the talk group may be stored in a memory at the zone controller for ease of retrieval.

At step210, the zone controller determines whether to alter the mode of the talk group. This determination may be based upon the transmission capability of the mobile station, the transmission mode of the RF site, user preferences, and the current mode of the talk group. The use of other factors is possible.

At step212, the zone controller alters the current mode of the talk group, as needed. This step is executed whenever the determination at step210indicates the mode should be changed. If no change is required, the current mode of the talk group remains unchanged by the zone controller.

Referring now toFIG. 3, an example of the impact of a mobile station affiliating with a talk group active in a call is described. At step302, a talk group call is active in a first transmission mode (e.g., TDMA or half-rate). At step304, a second mobile station that is only capable of operating in a second transmission mode (FDMA or full rate) affiliates with the same talk group during the active call. When this occurs, at step306, the active call is allowed to continue in the current transmission mode (TDMA or half-rate) but the affiliating mobile station will not participate in the active call.

At step308, once the call ends, subsequent transmission, until the talk group transmission mode is reevaluated, occurs in the second transmission mode (e.g., FDMA or full rate vocoder). This allows all mobile stations in the talk group to participate in the call.

Referring now toFIG. 4, one example of a device400(e.g., a zone controller) for dynamically adjusting the operating mode of a talk group is described. The device includes a controller402and an interface404.

The interface404receives transmission capability information406(e.g., mode of mobile stations, RF site capability, and user preference) from which a transmission capability can be calculated. The transmission capability406may be a full rate vocoder-only capability or a full and half-rate vocoder capability in one example. Other examples are possible.

The controller402is programmed to selectively adjust the current transmission mode408of the talk group based at least in part upon the transmission capability406of the mobile station, and the current transmission mode408of the talk group, and/or a transmission mode410of at least one RF site associated with the talk group and/or a user preference.

In one example, the controller402may be programmed to compare a first number of mobile stations operating in the talk group in a first mode to a second number of mobile stations operating in a second mode. Based upon the comparison (e.g., whether the first number exceeds the second number), the current transmission mode of the talk group may be altered.

The interface404may also be adapted to receive a user configuration preference. For example, the user configuration preference may be FDMA-only, full rate vocoder only, TDMA-only, half-rate vocoder only, or dynamic. The controller402may be programmed to set the current transmission mode of the talk group based upon the user configuration preference.

Referring now toFIG. 5, one example of an approach for determining the operating mode of a talk group is described. This example relates specifically to mobile stations that are operating in full rate vocoder mode or either full rate vocoder or half rate vocoder modes. However, it will be understood that other modes, protocols, and/or technologies can also be used and the specific determination of whether and how to switch the talk group mode will depend upon the nature of these modes, protocols, and technologies. In addition, other capabilities could be used to make these determinations.

At step502, it is determined whether a user preference of dynamic will be utilized. If the answer is negative, control continues at step504where the talk group is operated in user preference (non-dynamic) mode (i.e., the mode selected by the user).

If the answer at step502is affirmative, then at step506it is determined if at least one mobile station in the talk group is full rate only capable. If the answer is affirmative, at step508, the talk group is operated in full rate vocoder mode.

If the answer at step506is negative, at step510, it is determine if at least one mobile station is at an RF site that is only full rate capable. If the answer is affirmative, step508is executed as described above. If the answer is negative, at step512, the talk group is operated in half-rate vocoder mode.

Thus, approaches are provided that allow users to operate their mobile stations according to multiple modes or protocols. When the user roams to different RF sites or otherwise changes transmission modes, the user can continue communication and not have their communication interrupted or suspended.