Telematics in PDA
Telematics in PDAs deals with the networking of mobile handheld devices , especially via WAN , PAN and LAN . The technology thatis integratedin PDAs is explained and its economic importance is described.
The handheld has evolved from an electronic appointment calendar without functions and services beyond appointment management to a mobile office and multimedia device. In the course of development, telematics were also integrated into the PDA devices and the handhelds were "networked". Mobile communication was via the via cable , infrared or later via Bluetooth - radio data related mobile phone realized.
There are now devices that have their own connection to the GSM network, independent of the mobile phone . Various data services, such as B. GPRS , available with the handheld, with which e-mails can be accessed while on the move or surfed on the Internet using the WAP protocol.
With many PDAs there is currently the possibility of data transmission via an IrDA interface. With this type of data connection, which is usually established with a mobile phone or computer and only allows the transmission of small amounts of data, the PAN is set up to the other end device via infrared rays that are not visible to the human eye . The short range of a maximum of 5 meters, the necessary line of sight of the " infrared eyes " and the high susceptibility to interference make connections via infrared rays a less suitable means of establishing a PAN.
Today's smartphones also offer telephone and data connection functions as well as those of a classic PDA.
Bluetooth in PDAs
technology
The Bluetooth standard uses the 2.4 GHz frequency for license-free short - range radio connections and is increasingly being used in end devices. By eliminating license fees, manufacturers and end users are relieved of costs. Data rates of max. 1 Mbit / s (however, on average 128 kbit / s ) make Bluetooth particularly interesting for PAN users .
Other radio standards, such as WLAN or HomeRF , use the same frequency range and could hinder data transfer. To prevent this, so-called frequency hopping was integrated into the Bluetooth process.
The device changes the radio frequency about 1600 times per second in a certain frequency range. These frequency jumps largely avoid complications with other radio methods. In this way, despite the license-free frequency, a low susceptibility to interference can be guaranteed.
When using Bluetooth, the use of radio frequencies for communication means that a line of sight is no longer required as is the case when using the infrared interface .
This means that devices can be used to transfer data over a distance of up to 100 m, even through doors and walls. This way of working of Bluetooth would require a lot of electrical energy from every device if this problem had not been taken into account when defining the standard.
There are four basic modes that Bluetooth works with:
Active
- data is exchanged
- the energy consumption is highest
Sniff
- the end device “sniffs” for data packets at certain intervals
- can switch to active mode if necessary
- The energy consumption is lower compared to the active mode
Hold
- "Sleep state", but there is a logical connection to another device (data is not transferred)
- if necessary, you can switch to sniff mode
- the energy consumption is very low
park
- like hold mode, but does not switch to sniff mode
- energy consumption has been reduced to a minimum.
Applications
Bluetooth can be used to connect the handheld to various devices such as the home printer , PC , digital cameras or mobile phones . For many PDAs without integrated Bluetooth systems, there are plug-in modules for retrofitting.
GPS - Navigation is an important part of the transport telematics .
technology
GPS is a system for the precise determination of a location. It was developed for the US military in the 1970s and made available for civil use by Ronald Reagan after the accidental shooting down of a South Korean plane by Soviet forces .
The GPS system includes around 24 satellites orbiting the earth . GPS was initially mainly used for seafaring , later use by the automotive industry through integrated telematics systems in cars .
Solutions for using GPS have been developed for PDAs. Navigating by GPS using a PDA may require U. the upgrade of the PDA. Its processor must be powerful enough to ensure the correct display of the graphics and the digital maps. A color display improves the visibility of the graphic. In addition, a software package installed on the PDA with a GPS receiver installed in the car is required. The handheld must be brought into a position that is easily visible to the driver and connected to the receiver via a cable . The GPS receiver must be able to receive at least three to four satellites so that a position can be determined from them. It transfers the received data to the handheld, whose software evaluates it, calculates its own position and route from the (time) signal difference and shows it on the display .
Applications
With GPS navigation systems using a PDA, a distinction is currently made between onboard and offboard systems, both of which require a GPS receiver. On- and offboard systems differ as follows:
Onboard systems
- With these systems, the digital maps must be stored on the handheld before starting the journey. This requires a lot of storage space, which is not available on many end devices, but can often be expanded with additional memory cards . Another disadvantage is the lack of " dynamic navigation ". Since there is normally no connection to the GSM network, no traffic data can be queried via the Internet. In the worst case, this can result in the fact that you are approaching the 10 km long holiday traffic jam or suddenly you are standing in front of a blocked road. Listening to traffic reports would avoid this problem, but would also require the route to be recalculated.
Offboard systems
- In the case of offboard systems, the data received from the GPS device is sent from the PDA via the GSM network (either through its own network connection or via a mobile phone connected to Bluetooth) to an external server , which evaluates and calculates the route, which is then sent to for display transmitted back to the PDA and shown on its display . However, the network usage fees apply here. The advantage is that traffic jams from the external computer are taken into account and traffic jams can thus be successfully avoided in dynamic traffic management . The disadvantage, however, is that the route has to be recalculated even with the smallest deviation, which again results in transmission and sometimes software usage costs. In addition, it is sometimes impractical and annoying when, in hectic situations that require a quick decision, the necessary information is often available much too late.
Economical meaning
Work is still being carried out on the further development of the use of PDAs for GPS navigation in order to be able to offer comparable functions to the integrated GPS systems that are currently still having advantages. PDAs are to be given access to sensors in automobiles in order to achieve a higher accuracy of position determination. Studies are already underway on PDAs networked with the car, which also enable many functions to be controlled with the handheld.
GSM and GPRS in PDAs
technology
In Germany, the GSM standard uses the D - (900 MHz) and the E network (1800 MHz) and is used by many people in order to be mobile and always available.
The use was initially reserved for mobile phones and only possible via detours with cables or wireless data connections with the handheld, but the spread of smartphones is continuously increasing. These have been expanded to small multimedia terminals and form the link between PDA and mobile phone. The technology of the GPRS is used and serves to increase the utility value of the "smart companion". " General Packed Radio Service " enables faster data transmission in the GSM network. The maximum transmission rate of the GSM network is only 9.6 kbit / s and was probably also responsible for the lack of success of WAP . The basic idea of GPRS is simple: Settled is based on data volume rather than as previously after transmission time , there is virtually a permanent network connection ( " Always on ") permanently in one online remains and still pays only the transmitted data volume. This is due to the fact that the end device does not log into the cellular network as it did before (which does not cost anything) and only forwards this to an Internet dial-in node when a WAP request is made (from then on the meter starts to tick), but online immediately after logging into the network is. Since the device remains logged into the network, you are still online. The faster data rate (usually around 30 kbit / s) is achieved by packing the data into small packets, as indicated in the name .
Applications
What began with the C-Netz , which was only designed for around one million users and was therefore reserved for people who used the network for business, developed into a popular technology. It was actually only a matter of time before the PDA segment moved in the direction of GSM . Phone calls , emails , SMS and MMS can be sent with a smartphone .
The demand for location-based services , or LBS for short, is currently still very low, but forecasts predict that this demand will grow strongly in the next few years. With the LBT service or the location-based services, the position of the user is determined by locating the radio cell in which he is logged in. Information on hotels , parking lots , restaurants , doctors etc. in the vicinity can then be requested. The trend towards color displays makes this service even more attractive.
Economical meaning
With the emergence of the new class of smartphones , GSM and GPRS are becoming a more important part of everyday life and will increasingly replace mobile phones in the future . Even the simple PDAs that exist today are gradually being replaced and developing into a niche product. This merging of the products will cause a price war in the market and one or the other manufacturer will also disappear from the market.
WLAN in the PDA
technology
Like Bluetooth, WLAN operates in an ISM band . WLAN was originally developed to be able to access LAN without the hassle of cables. With the standards passed at the beginning of 2007, WLAN achieves a maximum data rate of 54 Mbit / s, the range is max. 300 m. The transmission power ( radiation ) used for WLAN is many times lower than with normal mobile communications , which even enables use in hospitals. And research continues:
IEEE 802.11b was further developed by the same institute and now enables the choice between 802.11a or 802.11g. The "g" version transmits on the same frequency, but achieves higher data rates of a maximum of 54 Mbit / s. The higher data rate, however, resulted in a reduced range; the technology can only be used within a maximum radius of 100 m. The continued usability of the old WLAN modules is advantageous. In contrast to its predecessor, the "a" version transmits in the 5 GHz range , which usually means that it is necessary to convert to new modules. The maximum data rate is also 54 Mbit / s with a maximum range of 200 m. WLAN is also very interesting for use with PDAs. Both handhelds with integrated WLAN modules and retrofit modules for older devices are available.
Applications
Many public as well as private institutions already operate WLAN islands, in which you can conveniently dial in and afterwards, for example, find the amount surfed on the bill next to the sundae in the café. Such “ hot spots ” are currently being set up in many countries, including Germany, in airports, cafes, offices, universities and other public places.
Economical meaning
In terms of price, WLAN was initially only accessible to the business class, especially since access was only granted to notebooks . Later, the technology became affordable for private users. Then the handheld developers got a taste for it, and now the technology is already being integrated into the PDA.
As long as UMTS, like WiFi, is only available in metropolitan areas, WiFi competes with UMTS , as higher data rates can be achieved with WiFi technology. According to the predictions, both will be able to coexist in harmony when the new UMTS network is fully expanded. WiFi will continue to supply cafes, airports, etc. with the higher data rates , and UMTS will provide nationwide coverage in Germany.
UMTS in PDA
technology
The current mobile radio generation 2.5 (MMS, GPRS etc.) is being further developed into the third generation ( UMTS ). In WCDMA , or 3G , as it is still called, is an entirely new network, the data rates up to 2 Mbit should / s permit.
Applications
With UMTS, the industry promises that video telephony , Internet , music , video streaming , live images and many other new, more colorful, better and more multimedia services will be possible, all of which are not yet predictable today.
Economical meaning
Not only the promising statement by Ericsson "UMTS connects the Internet with mobile communication " (quote) should make the consumer curious and of course also willing to pay.
In the field of device manufacturers, the presentation of smartphones with UMTS support is urgently needed, as the Japanese (for example Kyocera or Sanyo ) have already been able to gain experience through the early market launch in Japan and also want to use the German market ...