1. Field of the Invention
The present invention is directed generally to communication systems and, more particularly, to techniques for identifying a particular unit in a broadband push-to-talk communication system.
2. Description of the Related Art
Public wireless networks, which usually have wide and ubiquitous coverage, can be useful in providing private network-type capabilities. Public networks based on iDEN technology, for example, offer the ability to provide push-to-talk (PTT) capabilities similar to those in a private land mobile two-way network without the cost of building such a network.
There are a number of known systems available to implement a PTT communication system. In one example, the iDEN system remedied the drawbacks of traditional public wireless networks by placing all receiving units for a Group Call in receive mode at the same time. The iDEN network uses a time division technique which divides all communications into slices of time called timeslots. By directing all of the mobile units in a Group Call into a single timeslot containing the communications, all units receive the same communications at the same instant.
A PTT communication system is also known for use in orthogonal frequency division multiple access (OFDMA) systems. U.S. Pat. No. 8,095,163, which is incorporated herein by reference in its entirety, discloses a group communication system in which the wireless devices of all members of a group are all assigned the same subset of subcarriers on the downlink. With this approach, whenever there is a communication to the group, the data is encoded into the subcarriers and transmitted such that all group members receive the message at the same time.
Although group communications are possible with various communication technologies, it is desirable to identify the speaker in a PTT transmission. Therefore, it can be appreciated that there is a significant need for a system and method for user identification in a PTT communication system. The present disclosure is directed to techniques to provide such capability.
The present disclosure is directed to techniques for identifying the sender of a communication in a group communication setting. As appreciated by those skilled in the art, a push-to-talk (PTT) system generally involves short duration communications. In these short communications, it can be difficult to determine the identity of the person sending the communication to the group. This is especially true in an emergency situation where ambient noise may interfere with the listener's ability to identify the speaker. In other situations, some member of the group may not be known to all other members and thus the voice may simply by unrecognizable. In accordance with the present teachings, data is transmitted along with the voice message to unambiguously identify the speaker. Although examples are presented herein with respect to certain communication technologies, those skilled in the art will appreciate that the present teachings can be extended to other known forms of group communication.
Orthogonal frequency division multiple access (OFDMA) communication systems utilize a large number of closely-spaced subcarriers to transmit data. The input data is divided into a number of parallel data streams, one for each subcarrier. Each subcarrier is then modulated using a conventional modulation scheme, such as phase shift keying (PSK), quadrature amplitude modulation (QAM), or the like. The subcarriers are orthogonal to each other to prevent intercarrier interference. Those skilled in the art will appreciate that OFDMA technology has developed into a popular communication technique for wideband wireless communication.
As described in U.S. Pat. No. 8,095,163, a set of tones or groups of tones (i.e., subcarrier) are assigned to a particular mobile unit during a call setup process. The assignment of tones to a particular mobile unit during a channel set up operation and the actual communication process between a mobile unit and base station is well known in the art and need not be described in greater detail herein. However, the assignment of the same set of subcarriers to all devices in a communications group enables mobile units utilizing OFDMA technology to be synchronized such that communications in a push-to-talk (PTT) system are received simultaneously by all group members.
The communication techniques are implemented by a system 100 illustrated in
The base station 102 is communicatively coupled to a base station controller 130 via a communication link 132. In a typical embodiment, the base station controller 130 may provide operational control for one or more base stations 102. As illustrated in
In turn, the base station controller 130 is coupled to a mobile switching center (MSC) 134 via a communication link 136. As is known in the art, the MSC 134 is typically coupled to a large number of base station controllers and is responsible for switching and routing of calls to other base stations and/or a telephone network, such as the public switched telephone network (PSTN) 138.
The MSC 134 may also provide access to a core network 140 via a communication link 142. The core network 140 is the central part of a communication network that may include a number of functions, such as authorization, billing and the like. In addition, the network 140 may provide access to other networks, such as the Internet, for web applications via one or more gateways (not shown).
The MSC 134 is commonly used in circuit-switched networks. For packet-switched networks, a set of equivalent functions may be provided based on TCP/IP and VoIP technologies. The specific form of network elements may vary based on implementation details. However, those skilled in the art will understand that the OFDMA implementation of the present teachings may be applicable to a variety of network architectures.
In an OFDMA implementation, a plurality of mobile communication devices may be designated for operation in a Group Call function. When individual mobile communication units are designated as part of the same group, the wireless communication devices of that group will all be assigned the same OFDMA tones for communication purposes.
Also illustrated in
The information for each group is encoded in a conventional fashion using the assigned tones. When the base station transmits the encoded information using the assigned tones for a group, all members in that Call Group will receive the information simultaneously. Thus, the techniques may be used to support a push-to-talk system in an OFDMA communication network.
The concept illustrated herein is shown in
In accordance with the present teachings, a second group of OFDMA tones may be allocated to provide identification information related to the sender of the present communication.
On the uplink, the device activating the PTT button transmits a data packet that includes identification data with the transmitted message. In one embodiment, the data packet includes an Internet Protocol (IP) address and/or the media access control (MAC) address with the message. Alternatively, the data packet may include another unique identifier, such as a user name, device name, the actual user name, or the like. For example, the user ID may be “Unit1, George73, John Doe,” and the like. The extra identification can be in addition to or in place of the IP and/or MAC address.
On the downlink, each unit that is part of the designated group receives the message by decoding the assigned group subcarriers. In addition, each wireless communication unit in the group receives and decodes the designated identification (ID) subcarriers and displays the identifier on a device display.
When the transmitting unit ceases transmission, the unit transmits an end-of-transmission data packet containing the identification data (IP address or other identification) as described above. The end-of-transmission data packet is also retransmitted on a downlink using the designated group subcarriers and ID subcarriers, as described above, the receiving units decode the ID information and remove the displayed identity data.
The electronic device in
The electronic device of
The electronic device of
The wireless communication device in
Those skilled in the art will recognize that the PTT processor 170 may be implemented as a series of computer instructions stored in the memory 150 and executed by the CPU 148. However, the PTT processor 170 is shown as a separate block in the functional block diagram of
The various components illustrated in
The operation of the system 100 is illustrated in the flow chart of
During the course of the communication, additional group members may be added. The call set up process described in step 202 above may be applied to additional wireless communication devices. If the additional wireless communication device is to be added to a group (e.g. Group1), that wireless communication device is assigned the same group of OFDMA tones and ID tones previously assigned to Group1.
In step 204, one of the wireless communication devices detects PTT operation. As noted above, PTT operation may be manually initiated by depressing a PTT button on the wireless communication device or automatically activated, such as the VOX example described above.
In response to the detection of PTT operation, the wireless communication device initiating the communication will upload the ID data and message in step 206. As described above, the ID data will include the IP address, MAC address and/or different unique identity data as described above. In addition, the transmitting device can transmit additional data, such as location information. Those skilled in the art will appreciate that such location information could be valuable in an emergency communication setting, such as a fire fighting operation. The location data may be determined using one of more conventional location technologies (e.g., GPS data, triangulation data, signal strength data, and the like). The present disclosure is not limited by the particular form in which the location data may be derived or transmitted by the wireless communication device.
The message is transmitted to the base station and relayed to all other group members in the manner described above. If group members are connected to other base stations (e.g., the base station 104), the message is relayed through the communications system backhaul from the base station 102 to the base station 104 for transmission to group members coupled to that base station.
If sufficient spectral resources are available, the system 100 can assign a different set of OFDMA tones to use on the uplink for each of the wireless communication devices within a group. This is referred to as a contention-free uplink because each of the wireless communication devices has an independent uplink to the base station (e.g., the base station 102). The base station receives a message and identity data on the uplink from one of the wireless communication devices and relays that message and identity data to all of the group members in the manner described above. If multiple wireless communication devices send messages to one or more base stations on their respective uplinks, the system 100 can digitally mix the multiple uplink messages and transmit the combined messages on the shared downlink. This effectively provides a conference call between group members where one or more persons may speak at the same time.
Alternatively, if resources are scarce, it is possible to use a contention-based system in which group members must compete for available time on the uplink. If group members attempt to communicate simultaneously, the base station controller detects the collision and signals back to the wireless communication units in the group and a lock out tone is generated. The lock out tone alerts the users that simultaneous access attempts were made and that users should listen before talking and pace their access attempts. Because the collision detection and lock out tone generation happens so quickly, it appears that the lock out tone is generated as the user presses the push-to-talk-button on the wireless communication device.
On the downlink, the base station (e.g., the base station 102) transmits data using an assigned set of OFDMA message tones and ID tones in step 208. Because each of the wireless communication devices in the designated group has identical sets of OFDMA message tones and ID tones assigned for the downlink, each group member will receive downlink communications simultaneously. In step 210, each wireless communication device in the group receives the ID data and message. In step 210, the ID of the sender is displayed on the display 152 (see
In decision 214, the system determines if the PTT button has been released. If the PTT button is not released, the result of decision 214 is NO and the process returns to step 206 to continue conducting communications.
If the PTT button is released (or the VOX deactivated), the result of decision 214 is YES and, in step 216, the system performs a PTT termination process. As soon as the PTT processor 170 (see
As described above, the group communication can reserve the set of OFDMA message tones and ID tones for a prolonged period of time or may release the reserved tones when the PTT button is released. In the latter embodiment, the call setup, with the assignment of OFDMA message tones and ID tones is performed after the detection of PTT operation in step 204.
In the former embodiment, the call setup in step 202 is performed in an initial operation to establish the group communication. The assigned OFDMA message tones and ID tones are reserved for the duration of the group communication. At the end of the group communication, the system performs a call tear-down process. Those skilled in the art will appreciate that the call tear down process may vary depending on the particular communication technology. In OFDMA technology, the tear down process includes the de-selection of any tones that were previously assigned for the group message or for the ID data that frees the resources for other network operations. The process ends at 218.
The foregoing described embodiments depict different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely exemplary, and that in fact many other architectures can be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively “associated” such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as “associated with” each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being “operably connected”, or “operably coupled”, to each other to achieve the desired functionality.
While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that, based upon the teachings herein, changes and modifications may be made without departing from this invention and its broader aspects and, therefore, the appended claims are to encompass within their scope all such changes and modifications as are within the true spirit and scope of this invention. Furthermore, it is to be understood that the invention is solely defined by the appended claims. It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations).
Accordingly, the invention is not limited except as by the appended claims.
Number | Date | Country | |
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61782059 | Mar 2013 | US |