IMPROMPTU : Audio Applications for Mobile IP
Proposal for degree of Master of Science – Fall 2000
Kwan Hong Lee
December 11, 2000
Thesis Advisor
Christopher M. Schmandt
Principal Research Scientist
MIT Media Laboratory
Thesis Reader
Mark Ackerman
Principal Research Scientist
MIT Laboratory for Computer Science
Thesis Reader
Brian Smith
LG Electronics Assistant Professor
MIT Media Laboratory
IMPROMPTU : Audio Applications for Mobile IP
Abstract
IMPROMPTU is an Internet Protocol (IP) based audio platform for audio communication and mobile audio applications. Although mobile phones have provided great amount of mobility in our lives, they were fundamentally not designed with extensibility in mind. With IMPROMPTU, a variety of audio services, beyond the services that are offered on current mobile telephones can be realized, enriching the “always on” audio experience. Peers can know about one’s availability before they make calls; audio news can be streamed to a number of people in real time as a reporter is reporting an incident; one may be able to listen to the news and decide that it be stored in an audio archive to be played back later; parents can monitor their baby much more closely while away from home and away from their desk.
In my project, IMPROMPTU, I propose an extensible audio
platform that is composed of several distributed components working together to provide
various audio services to a client device. The client device will support high bandwidth wireless connection
and communicate with the distributed components to manage multiple audio
applications. IMPROMPTU addresses the
limitations of current mobile telephony by supporting multiple audio applications
with a coherent audio user interface.
The research results will provide guidelines for designing audio
interfaces for managing and interacting with multiple audio applications on a
mobile device. This will be useful for future broadband mobile communications.
Table of Contents
Applications and Their
Characteristics
Managing Multiple
Applications
System Architecture and Its
Requirements
Introduction
Personal computers have been a multipurpose platform
for a wide range of different applications.
Combined with the Internet, it has been the general platform for different
types of communication applications ranging from instant messaging, e-mail,
news groups to IRC chats. However,
these applications have been designed with the assumption that users are
sitting, stationary, and focused on the application. With increasing mobility, audio communication becomes more
important because one’s eyes and hands are needed for other tasks. Recent growth in mobile phone usage has
proven the value of voice communication for people on the move. Nonetheless, there are fundamental problems
with current mobile telephone systems that limit their functionality. These systems are based on the traditional
circuit switched phone network, and are not designed to handle multiple
applications or multiple communication channels. The call setup process is based on a simple alerting model, which
requires a caller to call a number and wait for the recipient to respond to an
alert before a call is set up or forwarded to the voice mail.
In my project, IMPROMPTU, I propose to build an IP
based mobile platform, which consist of a wireless client device and
distributed services that support multiple audio applications. I plan to explore different kinds of audio
applications that would be interesting for mobile users when high bandwidth
wireless connectivity is available.
These applications will impose requirements for the user interface and
the system architecture. By looking
into these requirements, I hope to overcome some of the limitations of current
mobile audio communications.
Related Work
Internet telephony protocols have been developed in
the last few years to send voice over the IP (Internet Protocol) network[1]. The two main
protocols that are being standardized are the H.323[2] from the International Telecommunication Union (ITU)
and the Session Initiation Protocol (SIP)[3] from the Internet Engineering Task Force (IETF). These protocols specify how audio and video
can be transported over the Internet and what kind of signaling protocol is
necessary. Recent development efforts
in SIP also include support for presence related protocols to provide awareness
between callers[4]. These
efforts will provide the standard protocols for transporting voice over the IP
network.
In mobile telephony, WAP Forum[5], NTT’s i-mode[6] and the “Voice Browser” Activity[7] are the main activities currently going on to provide
visual applications and interactive voice portals for mobile users. Their work will provide different services
that are useful to current and future mobile phone users. However, their applications are limited to
mostly visual or speech based interactive applications.
Other projects that also attempt to change the landscape
of the Internet and telecommunications are the ICEBERG[8] project at UC Berkeley and the Oxygen[9] project at MIT Laboratory of Computer Science, which
are larger in scale and scope. They also
explore the more fundamental levels of computing infrastructure and communication
infrastructure. The Ektara[10] architecture proposed by the Wearables group at the
MIT Media Lab also encompass a larger scope in wearable and ubiquitous
computing.
IMPROMPTU will provide guidelines for managing
multiple audio applications on a mobile device. In addition, by integrating the functionalities of instant
messaging, phone, radio, walkman, audio recorder and other audio applications on
a mobile device, it will provide a general platform for building and deploying
audio applications for a mobile user.
Applications and Their Characteristics
Audio
applications can be classified by their timeliness, real time or archived;
their mode of interaction, interactive, active or passive; their involvement of
users, single user or multi-user; their accessibility, private or public. These characteristics are not mutually
exclusive as the following table indicates.
The characteristics of these applications impose different requirements
for the system.
Table 1 Characteristics of Applications
|
|
Baby
monitor |
Presence
info (Aware-ness) |
News
broadcast (Radio) |
Community
news |
Personal
notes/ reminders |
Call
screening (Preview) |
Public
chat (IRC type) |
Private
chat |
Audio
books |
Music |
|
Real
time1 |
X |
X |
X |
X |
|
X |
X |
X |
|
X |
|
Archived2 |
|
|
X |
X |
X |
|
|
|
X |
X |
|
Delay
permitted |
X |
X |
X |
X |
X |
X |
|
|
X |
X |
|
Continuous (No
breaks) |
X |
X |
X |
X |
X |
|
X |
X |
X |
X |
|
Tolerate
breaks |
X |
X |
|
|
|
X |
|
|
|
|
|
Regular/
Timely3 |
|
|
X |
X |
X |
|
|
|
|
|
|
Interactive (no
UI) |
|
|
|
|
|
|
X |
X |
|
|
|
Interactive (UI) |
X |
|
X |
X |
X |
X |
|
|
X |
X |
|
Active (Pushed) |
X |
X |
X |
X |
|
|
|
|
|
|
|
Passive
(Polled) |
X |
X |
X |
X |
X |
X |
|
|
|
X |
|
Single
user |
X |
X |
|
|
X |
X |
|
X |
X |