Trevor Pering, Intel Research trevor.pering@intel.com by broverya79

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									                  Mobile Access Abstraction
                          Trevor Pering, Intel Research
                            trevor.pering@intel.com
Introduction
           The Mobile Access Abstraction (MAA) aims to define and understand an ab-
straction layer between a personal mobile device and the local infrastructure. The ab-
straction directly considers three main capabilities: the discovery/identification proc-
ess, the specific communication channel, and the existence of legacy devices. This
abstraction potentially encompasses a wide variety of connection technologies that
range from wide-area (e.g.,, WLAN, GPRS, Wi-Max) to local-area (e.g., Bluetooth,
Zigbee, UWB), and even contact-oriented connections (e.g., USB, NFC, Optical).
Furthermore, it applies to a variety of mobile devices, ranging from the new genera-
tion of high-end mobile computers, such as laptops or palmtops, but most poignantly
applies to the ecosystem of emerging advanced mobile devices, or smart-phones –
however, one significant aspect of the abstraction is the ability for the system to inter-
operate with the very large installed base of existing mobile devices that posses short-
range wireless capabilities but to not have the local computation and/or storage capa-
bilities afforded by their more advanced counterparts.
           The basic scenario addressed by the MAA is the seamless integration of mo-
bile devices with the digital home – or other suitably enabled infrastructure as defined
by standards such as the Digital Living Network Alliance (DLNA) [dlna]. For exam-
ple, consider the case where a group of teenagers convenes at a house, and they would
like to easily play and share their personal music or photographs, which are stored on
their mobile devices. In order for the best overall experience, they would like to use
the stereo system and TV already present in their home, and access the content on
their mobile device without a lot of unnecessary attention placed on the underlying
technology. This scenario is almost completely supported by existing digital home
systems, which aims to provide a seamless platform for users to access and consume
digital media in their home; however, the step of actually connecting the users’ mo-
bile devices into the home infrastructure is non-trivial, and requires a fair amount of
interaction. The basic abstraction described in this paper apply not only to the above
scenario, but any number of similar situations that involve mobile devices entering
into a smart environment – and enabling seamless access to the content and applica-
tions stored on those devices.
           Currently, in order to connect a mobile device to the local infrastructure, the
user must go through a lengthy discovery and connection process. The exact details
depend on the exact underlying technology used. Using Bluetooth, for example, one
must first perform a local device discovery, then connect to the appropriate access
point, select the appropriate service – then, in order to access their content, they must
go to the access device (TV) and select their device and browse for their content.
Similarly, for WiFi, the user must first connect to the local network, and then access
their content through the intended display device. Although this process can be
somewhat streamline for “repeat appearances” – where somebody sets their device to
auto-connect to a given network name – it is still quite laborious while interacting
with content in new locales.
        The benefit of abstracting the connection process for mobile devices supports
three main hypothesis:
     • The abstraction will improve the user experience by making it easier for
        them to connect their devices and platforms together – basically remove
        many of the technological ease-of-use barriers that currently impede access
        to mobile systems.
     • Abstracting the network connection for mobile devices will allow the system
        to optimize the channel with dynamic and automatic trade-offs between dif-
        ferent connection technologies.
     • A layer of abstraction will enable systems to better incorporate the myriad
        emerging connection technologies, such as UWB, Zigbee, NFC, etc…, with-
        out requiring major changes in the user experience or installed base of con-
        nection components.

        Furthermore, given these basic objectives, the MAA is based on three main
technological tenets, which provide it’s basic foundation. In essence, these are as-
sumptions by the system about how it should and/or can behave:
    • It should be possible to initiate and complete a transaction with a mobile de-
        vice completely from the infrastructure. This may not be desirable for a vari-
        ety of reasons, but it should be supported by the underlying system capabili-
        ties.
    • The network view of the mobile device should be independent of the connec-
        tion technologies used. This both makes it easier to accommodate either new
        or legacy technologies, as well as makes it possible to better optimizing the
        underlying channel.
    • It is not realistic for a mobile device to maintain a connection to all potential
        local networks – either due to technical capabilities, underlying system ef-
        fects such a battery power, or basic network security boundaries.

          The MAA aims to provide capabilities that should be supported by the sys-
tem as a whole, although it might not be desirable in every situation. For example,
the first assertion above is that it should be possible to connect directly to a user’s
mobile device, but it may not be desirable to do so in order to implement a good secu-
rity policy. However, there are likely lots of situations where the behavior would in
fact be desired, and unless the basic capability is supported there is no hope of the
proper solution being realized. In a real environment many important aspects of a
system, such as security, ease-of-use, et. al. present fundamental trade-offs, and the
MAA open the doors to a wider-range of possibilities, expanding on the limited range
of operation afforded by existing technologies.

Implementation
        The MAA could be realized at several different places in the system. For ex-
ample, every PC or digitally-enabled appliance in the system could be able to recog-
nize and negotiate with other devices to provide a seamless web of interaction be-
tween devices and the infrastructure. However, this approach relies on inserting new
technology into several places in the system, as well as potentially adding capability
into new mobile devices. Although technically possible, this solution is probably not
feasible until a clear demonstration for the capability has been shown in a mass-
market context. Meanwhile, a small adaptor device, which resides in the local infra-
structure and acts as a bridge or proxy between the wireless and wired networking
worlds is capable of realizing the MAA without requiring extensive changes in the in-
frastructure. For example, the device could perform Bluetooth discovery and represent
discovered devices on the local DLNA network, allowing users to initially see and
connect with their mobile device without forming a complete connection, and then
triggering a full connection when appropriate. Furthermore, this device could act as a
proxy for legacy devices – redirecting traffic, for example, to an Internet-based web
page.
          The basic goal of the MAA is to bring the various wireless technologies into
the fixed-infrastructure world used by home-networking systems. For example,
emerging UPnP and DLNA systems rely on multicast and unicast packets, assuming
that all entities on the network have a valid local IP address. However, connection
                                                                Infrastructure compo-
 Backbone Network                           Infrastructure
                                                                nents can discovery the
                                            PC or TV            device using standard
                                                                DLNA techniques (mul-
 4                                                              ticast-based), irrespec-
 When appropri-                                                 tive of the underlying
 ate, a full-               Wireless Dis-                       connection technology.
 featured connec-           covery
 tion can be                                                                          3
 made to the                Proxy                    Before the device is com-
 mobile device.                                      pletely connected, the WDP
                                                   2 maintains a database of lo-
                                                     cal devices, serving up lo-
 Mobile                1                             cal content.
 Device                Initially, the mobile device is only connected
                       to the system through the Wireless Discovery
                       Proxy (WDP), using the appropriate wireless
                       discovery format (such as inquiry scan)

technologies fundamentally don’t allow devices to communicate until they are con-
nected to the network – for wired systems like Ethernet, this involves plugging in a
cable, for WiFi it requires you to enter the ESSID and possibly WEP-key for the local
network, and for Bluetooth it requires you to discovery the connection and connect
using a specific service (Personal Area Networking). So, the trick with abstracting
away discovery is to present the various wireless discovery systems on an IP based
network, without requiring all devices to connect to that network.
          The specific channel for communication used is an interesting aspect for ab-
straction, not only because it affords a better user experience, but it also enables better
overall system optimization. For example, once a system is connected to a network,
and assuming it has both Bluetooth and WiFi connection options available, it is feasi-
ble for that system to dynamically switch between Bluetooth and Wifi, based on its
communication needs, to minimize the overall power consumption of the device.
Since Bluetooth is better for idle situations, while WiFi is better at active transmission,
a dynamic combined system can do better than either technology on its own. This ca-
pability, which has been successfully demonstrated as part of the CoolSpots system
[coolspots], can be preformed in a manner transparent to higher level applications on
the network – presenting a consistent-IP view into the communication channel, while
switching between various underlying wireless technologies. This same basic idea can
(and should) be easily extended to other technologies, such as USB, UWB, Zigbee, et.
al., to provide a uniform abstraction across all connection technologies to not only af-
ford the best user experience, but also minimize the underlying power consumption of
the system.
          One other important aspect of an abstraction system is to enable legacy de-
vices, embodied by the already large installed base of mobile devices, to offer some
integration with infrastructure-based systems, as a path for complete adoption of the
system. This ability will in effect enable the entire ecosystem, by lessening any
chicken-and-egg binds introduced by the system requiring changes both to all mobile
devices and the infrastructure in order to be useful. Fundamentally, this aspect of the
system links the basic wireless capability found in most mobile devices, in the form of
basic Bluetooth capability, with web-based resources, to provide an emulation of a
smart-phone capability. Instead of carrying your data with you, your mobile device
carries a pointer to the data, which in turn is available on the Internet. Then, as mobile
devices become more capable, they can provide the content directly instead of requir-
ing an indirection. Furthermore, indirection the data access has an advantageous
power proposition for the mobile device, by potentially providing bulk content with-
out taxing the power source for the device (e.g., by transferring the data over a wire-
less connection).

Conclusion
           The Mobile Access Abstraction (MAA) is a technique that will better enable
mobile devices to be integrated with emerging infrastructure standards. Currently, the
basic technologies enabling mobile devices to be integrated with computing compo-
nents such as TVs and PCs either exists or is starting to exist, but the user interaction
is still fairly clumsy and awkward. By addressing the connection barrier with the ap-
propriate abstraction, the system can not only be optimized to behave better (e.g.,
lower power consumption), but it can also be streamlined for the user. By introducing
a Wireless Discovery Proxy (WDP) into the environment, the MAA can ease the tran-
sition between devices, allowing devices in the fixed infrastructure to discover and
view mobile devices that have not yet been fully connected to the environment.

References
[coolspots] Trevor Pering, Yuvraj Agarwal, Rajesh Gupta and Roy Want, "CoolSpots:
Reducing the Power Consumption of Wireless Mobile Devices Using Multiple Radio
Interfaces", ACM MobiSys 2006, Uppsala, Sweden June 19th, 2006. PDF

[dlna] Digital Living Network Alliance – http://www.dlna.org/home

								
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