Research Plan
iRespond is a device that will provide an immediate response to a certain location where
help and assistance is needed. To provide this type of service, communication is needed between
distinct points. The patron, cell tower, 911 call center/dispatcher, and emergency vehicle are all
the points that need to be contacted.
Initially, a device or beacon is activated by a patron. This sends a signal to the closest
cellular tower in range. The transmission is sent to the closet appropriate 911 call center
according to the location of the cell tower.
The 911 dispatcher communicates with
emergency vehicles and sends them to the
Cell
Patron
location of the patron where the assistance can
Tower
be given. Different protocols have to be
followed in order for this transmission to be
sent successfully.
It is important to remember that
Emergency
911 Call
Response
iRespond will not be providing voice-to-voice
Center
Vehicle
communication with the patron and the 911
dispatcher. All the iRespond device does is
911
triangulate the device’s current location using
Dispatcher
GPS and nearby cell towers and transmits this
location data along with a prerecorded
message.
The infrastructure to communicate between cell towers and
911 call centers has been established and is maintained by existing
companies. The technology is proven and works with success so
iRespond takes advantage of that with our lone device.
To establish communication with cell towers, we use CDMA
technology. Currently, cell technologies are very competitive in the
United States and provide mainly two choices with communication
protocols, CDMA and GSM. CDMA has the market in the Americas. Globally,
GSM is the majority. It makes sense for iRespond to use CDMA because of the
coverage area and the US is the primary market. We want to reach as many points as possible.
CDMA communication is a newer technology built from the bottom up. The origins
come from AMPS or easily called the Analog signal. This is a lower 800MHz frequency that is
used to establish communication. In order to establish communication, one specific radio
frequency is used. Using this Analog signal does not provide a secure and reliable
communication link. Close radio frequencies (other established calls) gave way to interference
problems and “ghostly” voices that were from other calls that were very close in radio frequency.
And another major con was very poor battery life.
One way of improving technology was CDMA. CDMA provides a more secure digital
signal. A higher frequency is used and the signal to establish communication is spread across
multiple frequencies. The signal is sent using about 1.5MHz of the radio spectrum which
provides the security and reliability. The CDMA chip on the cell phone and the cell tower
interpret the signals easily and can only be interpreted from source to target only. And also
going digital gives about 3-4 times more battery use.
CDMA Digital would be the way to go, but not everyone has a CDMA chip. The
competitor GSM is another technology. The problem with GSM is that the technology is not
well established in the United States. Another problem with GSM is that the technology is based
on old technology developed many years ago. The developers wanted to provide an easy
upgrade for users by enhancing the existing means of communication which is proving now to be
a critical mistake. And now Qualcomm is establishing a new chip that upgrades both CDMA
and GSM so that one unique technology can be used. GSM does work but not as superior as
CDMA.
iRespond will need to follow these changes and upgrade as needed. Right now Analog is
being phased out. Analog is still ideal though because of the large signal area it provides. The
signal being used by the device would use a CDMA signal and when not available use the
Analog signal to establish communications. As newer and better emerges, iRespond will
upgrade the communications chip that will provide the best means of communication.
Once communication is established a message is sent. The message consists of the
location data and the prerecorded message.
The location data is gathered by triangulation. Two
methods of triangulation that will be used: GPS and cell
towers. GPS uses current satellite location to calculate the
longitude and latitude of the location. The more satellites the
iRespond device is able to connect with provides a precise
location. At least two
need to be established
before any triangulation
can be done. This calculation is done on a chip on the
iRespond device. Storms, trees, buildings are among the
things that can block a successful GPS lock with a satellite.
Also, the total time to find the exact location can be
cumbersome at times especially with fewer satellite locks.
But because of how precise the triangulation is GPS is very
ideal in providing location data.
Cell tower triangulation also provides location data.
From the E911 mandates, triangulation must be possible
using the cell towers. Triangulation is a lot quicker using
cell towers since all towers are fixed. Three towers are
required to establish a successful triangulation. The degree
of preciseness is about 20 feet, but this will not be met until
full E911 Phase 2 compliance has been met by all cell
towers. The mandate required E911 to be completed by
December 31, 2005. Currently, extensions have been
provided to companies because of the difficulty and man
hours required to meet the mandates.
Antennas for both GPS and cell are used for receiving the GPS satellite data. Cell towers
communicate with the device to give the exact triangulation point of the signal. The size is
conveniently compact to provide for a very small device. Going with a big antenna does
improve reception, but doing so goes against our compact device idea. The device has to be able
to sit inside your hand or pocket comfortably without give the feeling of weights. iRespond is
not designed to be a hassle for the patron.
The second part of the message is the prerecorded message. The prerecorded message
consists of the name, birthday, age, optional medical information, contact information, and
anything that patron would like recorded. The message is created during the registration process
of the device in which a separate dial-up connection is established that downloads the
prerecorded message and account information. The prerecorded message is encoded using the
same technology that is used by MP3 players today to encode music. The technology allows us
to create a sound file that is very small and understandable to the 911 dispatcher. LAME MP3
encoding is free to use and can be easily used to create on-the-fly sound files. The prerecorded
message is stored directly on the device on a flash memory device. The flash memory does not
need to be plentiful in size since the audio file is very small to begin with. Once the iRespond
device establishes the connection the prerecorded message plays. A decoder translates the mp3
sound file to audible audio that is directly connected to what is equivalent to a microphone (It is
important to note that the iRespond device will have no audible feedback or input meaning no
earpiece or microphone).
Once the 911 dispatcher gathers all the required data, the 911 dispatcher informs the
emergency response vehicle of the precise location and of all data that is stated on the
prerecorded message.
The iRespond device is going to be designed for durability using injection molding of
hard plastics. The device is rechargeable using the base station provided with the device. The
lithium battery provides many charges and is easily changeable at the end of the battery’s life
time. Batteries are also being improved with technology that charges a battery full in under 10
minutes and provides almost a month of standby battery life.
iRespond has many means of improving. As stated earlier, cell chip technology is
advancing everyday. Triangulation is getting more precise and closer to the exact location. Cell
coverage is expanding as every month new towers go up.
These among others provide improvements that are ideal to development of the iRespond
device.