Advances in wireless technology are enabling operators to offer robust applications while leveraging the power of today’s converged networks. With constant changes in the telecom industry, application developers and telecom operators are continually striving to develop innovative services to meet market demands and to increase average revenue from the subscribers. While advanced multimedia applications like mobile TV and video are being touted as the next killer apps to revolutionize the market, voice still remains a driving force. Take SMS for example — the largest and most successful mobile application available today. By adding voice to SMS capabilities, SMS can easily become faster, easier, and more personal without changing its inherent interoperability and ease-of-use benefits and can be added to a wireless infrastructure with minimal impact.
In general, communication between people is largely dictated by the device on hand. When on a wireline or mobile phone, the choice is voice; when using a PC or PDA, the choice is text. But the mobile user has an added advantage of using text in addition to voice via text messaging. SMS text messaging between mobile subscribers has exploded over the last few years, especially among youth and teenage subscribers who use text messaging as a fast and efficient way to reach their friends and family. Ovum forecasted mobile messaging to increase by nearly 50% between 2006 and 2009 (Ovum: Wireless Multimedia Forecast, September 2006).Ovum attributes this growth to the always reachable society and our need to communicate a thought to someone else regardless if they are unable to take our call.
However, significant disadvantages of text messaging include the time it takes to type out a message using the limited mobile phone keypad and the lack of emotion that only a voice can deliver. Many resort to the cryptic computer-speak prevalent within computer messaging today, leaving a mobile user in receipt of these abbreviated messages at a disadvantage.
Voice SMS is a fast way to send a short message to another mobile subscriber that can be retrieved at the subscriber's convenience. In that sense it’s similar to an SMS text message. But Voice SMS is much easier to use. There are no keystrokes to compose the message, you just talk. When a Voice SMS is sent, an SMS text message is received saying "You have a Voice SMS. Click here to listen to your message." One click and you’re listening to your new message via a human voice. In some implementations, it says "Dial *0* to listen to your message. That’s four clicks with the "Send" key, but it’s equally easy for users.
There are additional advantages for Voice SMS over text SMS. The text user interface on mobile phones is great if you use a European language, Kanji, or another widely practiced language. But once you get beyond the top twenty languages, there is little or no support for text messaging. And of course, text messages are of no use to people who are illiterate.
Voice SMS is perfect when the need to communicate is strong and a live conversation is not in order—for example when you think the other party is likely to be asleep, in a meeting, or in a noisy environment. Voice SMS is a convenient way to give call recipients information or initiate a non-real time conversation, while allowing them to delay their response until it is convenient. Even more important, voice conveys emotion and can provide more in-depth understanding than any text message.
Developer’s Challenges in Delivering Voice SMS
The core functionality of any messaging application is voice processing. Recording and playing messages, playing prompts, and recognizing touch-tone key presses all require high-performance media services and mechanisms that translate between text and the voice world. This is no different for a proficient voice SMS system. When installed in a carrier infrastructure, high availability is a priority to ensure that mobile users never lose this service.
But how does a developer began to address the multiple issues for sending and receiving Voice SMS messages within today’s mobile world? What type of user interface is required when multiple handsets are in use? How does the developer address billing within the walled garden of the mobile operator community and the various nuances of mobile customer accounts (pre-paid, post paid)? How does the system locate and direct the voice message to the appropriate recipient within the mobile system?
Critical to the success of a Voice SMS architecture is the ability to manage the call flow once the caller sends the voice mail. A Voice SMS platform that manages message processing, billing, and directs the voice message to the appropriate recipient is required for a robust and valid Voice SMS.
Voice SMS messaging applications create greater demands for network connectivity. Robust TDM and SS7 support ensures that voice messages can be heard at any time and require an integrated voice service engine to appropriately connect to the network and application resources to convert and transfer the voice messages.
Here is a sample construct of a Voice SMS system using specific servers to manage the Voice SMS call flow:
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Party A decides to send Party B a voice message requesting a lunch meeting. Party A records a message on a hand set, selects Party B’s mobile number from the directory, and then pushes the send button on the mobile handset.
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A VoiceXML browser, designed to manage the call "traffic" for this application, contacts an application server that an incoming voice call is coming for Party B. The application server’s role is to interact with the mobile switch to determine the route of the call to Party B’s handset and injects a short SMS message to Party B that a voice message is pending. Within this SMS message might be a short code (e.g. *0*) for Party B to dial from the handset to listen to the message.
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Party B retrieves the SMS message, dials the short code, and plays Party A’s voice message. |
Solutions from NMS
NMS Communications provides the building blocks needed to develop and deploy a robust and fail-safe voice messaging system. NMS’s Vision VoiceXML Server is specifically designed for speech-enabled applications such as Voice SMS within PSTN and VoIP networks. It supports the industry-standard VoiceXML scripting language, as well as additional extensions based on XML that allow for outbound dialing, caller authorization, and information collection of caller details.
Figure 1: Voice SMS Platform
For more information on how to develop Voice SMS applications using the Vision VoiceXML server, please contact NMS.