Feature Displays & UIs
Navigating the wireless capability maze
Adaptive Modules’ Marketing Teamdiscusses eight critical considerations for integrating GPRS/3G/LTE into new products and what is currently available
aving been regularly exposed to the jingo and the value proposi- tion adopted by the ‘M2M’ or ‘Internet of Things’ market, many product manufacturers are embarking on new product develop- ments involving a GPRS, 3G or 4G communications element.
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Many are travelling down this path for the first time unaware of the full scope of options available to them. To aid the journey this article highlights eight critical considerations in GPRS/ 3G/4G enabled new product design. 1) Use cellular ‘modules’
A cellular module is the key building block for new designs. Manufacturers such as Telit, Cinterion and Sierra Wireless provide a wide range of mod- ules for GSM and CDMA networks. They typically have a UART or USB interface and leverage AT commands for control of the network connection. Chip level designs are rarely imple- mented at M2M volumes due to the ongoing cost of product compliance. 2) High level AT commands reduce programming time
The GSM07.07 and GSM07.05 stan- dards govern basic AT guidelines for GSM dial-up connections. However, each module vendor will have propri- etary high level commands that can, for example, open up a socket on a remote server with a single command. Thanks to the integrated TCP/IP stack, this can be extended to an HTML connection directly from the module to provide quick and easy web integration.
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3) Programmable modules offer innovative ways of working
Many modules have application space and can run a C, Java or Python appli- cation onboard. Benefits include: •«Saving the cost of a separate micro from the BOM of cost-sensitive products
•Offloading burden from existing host processor
•Compressing acquired data before transmission to reduce airtime costs •Provide a layer of protocol translation 4) Chip SIM for harsh environments or airtime control
It is now possible to buy chip SIMs (without significant MOQs) that can use any available network on cost- effective MB (MegaByte) tariffs. These SMT devices can be fitted at time of manufacture either as a single robust SIM connection or in conjunction with a traditional SIM card holder for maxi- mum flexibility.
At present, chip SIMs cannot be reflashed to change operator but many in the industry suggest that this move is not far away. 5) Integrated A-GPS for fast TTFF Many cellular modules feature inte- grated GPS with ‘Assisted GPS’ func- tionality. This allows the modules to reduce TTFF (Time to First Fix) by leveraging the onboard 2G/3G/4G Internet connection to download required ephemeris (satellite constel- lation) data ‘quickly’ on boot up. An integrated module with both cellular and GPS functions inside can
make the control of Assisted GPS func- tion easier than with discrete compo- nents. In very low power applications, the use of individual GPS and cellular modules may be preferred. 6) Cell location as a supplementary positioning tool
A recent development in cellular mod- ules is the ability to triangulate the position of the product based on signal strength readings from all visible cell towers. A single AT command can be used to force a network scan and send the results to a remote server that acts as a look-up database of cell towers. Given the cell ID information, the server simply returns a latitude, longi- tude and degree of error in the result. Accuracy is a function of the number and proximity of cell towers so is more accurate in built-up areas as opposed to rural areas where cell tower density is low. 7) Form-factor compatible modules Several module vendors now manu- facture 2G, 3G, 4G and CDMA mod- ules in the same form-factor/footprint allowing a single PCB to accommodate all types of radio interface. In an uncertain market (Will 2G disappear soon? Will CDMA networks all migrate to LTE?). It is very convenient and cost-effective to be able to change the module at time of manufacture to sup- port different product SKUs. The key area where this is being used at present is to enable people to design a low cost 2G product with an easy upgrade to path to 3G. With a rap- idly reducing average selling price, 3G modules will start to become the de- facto choice for all but the highest volume M2M applications. 8) System architecture
One of the most critical considerations for successful product deployment is to have properly considered overall system architecture, much of which is driven by the choice of the right air- time package.
Adaptive Modules
www.adaptive
modules.co.uk Enter 204
SIM card vendors are not limited to just providing airtime but can provide SSL VPNs, IPSEC VPNs, public IP SIM cards, private APNs, SLAs and much more. A full description of system archi- tecture is beyond the scope of this short article but it is imperative to have researched the type of SIM/air- time platform you plan to use and that the real-world airtime costs will make the application commercially viable – a common oversight when caught up in the momentum of a ‘good idea’. Adaptive Modules are hosting a free M2M seminar on 10th October 2013 at Hove County CC where a much more detailed overview of the commercial and technical considerations of M2M will be provided. To find out further information about this event email:
seminars@adaptivemodules.com
OCTOBER 2013 Electronics
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