QChat
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QChat is a Push-to-Talk (PTT) technology developed by Qualcomm.
The QChat software application was developed by Qualcomm Internet Services (QIS) [1] a division of Qualcomm and part of the Qualcomm Wireless and Internet group [2]. QIS offers a set of software products and content enablement services to support and accelerate the growth of the wireless data market [2].
Qualcomm developed QChat to provide a reliable method of instant connection and two-way communication between users in different locations, but operating within the same type of network architecture. Prior to the existence of cellular and personal communications services networks, this type of communication was limited to private Land Mobile Radio System (LMR) technology used by public safety and utility service agencies. LMR has limitations, specifically its usage can be restricted by geographic coverage area and by use of disparate frequency bands.
QChat, an application developed for the BREW platform, is a PTT communication technology for 3G networks. QChat handsets and server software allow users to connect instantaneously with other QChat users anywhere in the world with the push of a button. In addition, QChat enables one-to-one (private) and one-to-many (group) calls over the 3G networks [3].
QChat uses standard Voice over Internet Protocol (VoIP) technologies. VoIP is a voice delivery mechanism that uses the Internet Protocol to manage the delivery of voice information. Voice information is sent in digital form over IP-based data networks (including CDMA) in discrete packets rather than traditional circuit-switched protocols such those used in the public switched telephone network (PSTN).
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[edit] How Does QChat Work?
QChat users on 3G wireless devices can connect to each other worldwide, in either private or group calls, with the push of a button. QChat uses Voice over Internet Protocol (VoIP) technologies to allow subscribers to communicate by using a PTT button on the handset instead of making a standard cellular call.
QChat calls are created by combining separate point-to-point connections between each IP endpoint; the process is managed by the QChat Applications Server, which is deployed on the carrier’s IP-based Wide Area Network (WAN).
To initiate a call, a user presses the PTT button and receives an immediate indication of whether the call recipient is available. If he or she is, the caller can begin speaking immediately. If the recipient is unavailable, the caller will simply hear a negative response tone instead of a busy signal or voicemail [3].
[edit] What Are the Advantages of QChat?
Because QChat uses VoIP architecture, subscribers using standard 3G CDMA data networks worldwide will be able to push a button to talk. For instance, a QChat user in Boston could make a direct push-to-talk connection with another QChat subscriber in Beijing.
QChat enables end users to set up QChat groups dynamically from the handset without the need for action from a system administrator. Because QChat is implemented on top of BREW, consumers can choose from a wider variety of handsets from multiple handset manufacturers.
The QChat application benefits from CDMA’s inherent security attributes. Since CDMA signals are digital in nature and transmitted across a wide bandwidth (as opposed to transmission over discrete frequencies), it possesses a low probability of interception and a low probability of detection, thus ensuring that transmissions are resistant to decoding and eavesdropping.
In addition, QChat offers these advantages:
- Support for over-the-air upgrade of QChat client software via the wireless download feature of the BREW platform
- Dynamic management of group membership by subscribers (i.e., the ability to add or remove participants at any time, on their handset)
- Ad hoc creation of chat groups on the handset, in addition to the standing groups that an administrator may establish
- Easy implementation of the user interface across multiple device types and in multiple languages.
[edit] QChat and Sprint
On October 16, 2006 Sprint Nextel announced an agreement with Qualcomm to use QChat to provide high performance push-to-talk services to its customers on the Nationwide Sprint PCS Network, using CDMA2000 1xEV-DO Revision A technology.
QChat is able to interoperate with iDEN push-to-talk handsets on the Nextel National Network, with claims by Sprint of call set-up latency of less than one second between handsets [4]. A video demonstrating the speed and interoperability has been posted at YouTube.
Sprint's phones supporting QChat technology were released starting in April 2008, with a trial of business customers in Kansas and Colorado [5]. Sprint then announced that the Nextel Direct Connect devices powered by QChat were available in more than 40 markets in June 2008 [6].
Supported models include [6]:
- Sanyo Pro 200 (Discontinued)
- Sanyo Pro 700 (Discontinued)
- LG LX400 (Discontinued)
- Motorola V950 (Discontinued)
- Samsung Z400 (Discontinued)
- Samsung Z700 (Discontinued)
QChat has been launched in a total of 54 Sprint markets [7].
[edit] See also
Article with technical details of QChat
Integrated Digital Enhanced Network (iDEN)
Code division multiple access (CDMA)
[edit] References
- ^ [1] Qualcomm Internet Services website
- ^ a b [2] Reuters Company Overview, Qualcomm Incorporated
- ^ a b [3] QChat website
- ^ [4] Press Release: Sprint Nextel Teams With QUALCOMM and Lucent Technologies to Extend Industry-Leading Push-To-Talk Services with QUALCOMM'S QChat Solution, October 16, 2006
- ^ [5] Press Release: Sprint Business Customers in Kansas, Colorado Get Sanyo Pro-200 and Pro-700 Phones for Nextel Direct Connect Plus Sprint Mobile Broadband, April 10, 2008.
- ^ a b [6] Press Release: Sprint Customers in 40+ Markets Can Soon Get Nextel Direct Connect(R) Plus Sprint Mobile Broadband on 4 New Phones, June 12, 2008.
- ^ [7] Saabedra, Humberto. Sprint Adds 14 Additional QChat-Capable Markets. PhoneNews.com. July 10, 2008.
