Global Journal of Advanced Engineering Technologies, Vol3, Issue4- 2014 ISSN: 2277-6370
414
Figure 1: GSM/GPRS Modem Communication
GPRS: General packet radio service (GPRS) is a packet
oriented mobile data service on the 2G and 3G cellular
communication system's global system for mobile
communications (GSM). GPRS is a best-effort service,
implying variable throughput and latency that depend on
the number of other users sharing the service
concurrently, as opposed to circuit switching, where a
certain quality of service is guaranteed during the
connection. In 2G systems, GPRS provides data rates of
56–114 k bit/second.2Gcellular technology combined
with GPRS is sometimes described as 2.5G, that is, a
technology between the second (2G) and third (3G)
generations of mobile telephony.
It provides moderate-speed data transfer, by using unused
time division multiple access (TDMA) channels in, for
example, the GSM system. GPRS is integrated into GSM
Release 97 and newer releases.
Working of GPRS: GPRS is a network overlay to the
existing cellular network. It uses the nature of IP
transmissions to its advantage. Because IP traffic is made
of "packets", the network does not need to have
continuous data transmission. Thus, IP traffic can easily
share the channels. A user may be receiving or
transmitting data while another one is reading
information. The second user does not need to use the
channel during this time, and it makes packet networks
more efficient than circuit-switched networks (2G), where
the channel would be in use, regardless of the user
transmitting or not. GPRS data rate is 171.2Kbps per
channel, but users will experience something lower than
this, because of the nature of channel usage explained
before. The connection to the GPRS network is always
on, but the device needs to connect to the data terminal
(Pocket PC, notebook, cellular phone). The connection
times are of course much lower than dial up. My personal
tests show GPRS connection to be ready to use in 7
seconds, while a dial up requires around 35 seconds to be
in a ready state.
IV. AMR (Automatic Meter Reader)
The Automatic Meter Reader system is a kind of box
which contains different types of components is
fabricated in such a way that helps to read the meter and
send data to server.
Usually the complete box is made up of fiber which gives
protection and guarantees a long and reliable lifetime.
The different types of components that we have used in
the analogue junction box are:
· Switched Mode Power Supply (SMPS)
· Sim900-GSM\GPRS modem
· Micro controller (c8051f340, c8051f350)
· EEPROM (AT24C02)
· Flash memory (S25FL016A)
· RS232 (serial communication)
· Antenna
Figure 2: Automatic Meter Reading System
As soon as the power supply is given to the SMPS it turns
on the analogue junction box. The microcontroller
initially checks the baud rate and all port configurations.
Later it checks the speed and frequency of data to
transfer. The microcontroller initializes the settings from
EEPROM and collects the stored data from the flash
memory. The data is transferred through the UART in
between the GPRS/GSM modem and the microcontroller.
Figure 3: Block diagram of AMR
(10 páginas)
Manymanuals.com
Manymanuals.de
Manymanuals.fr
Manymanuals.it
Manymanuals.pl
Manymanuals.cz
Manymanuals.es
Manymanuals-pt.com
Comentários a estes Manuais