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on the amount of activity taking place in any given cell – and the response of an M2M application when a communication link fails is one of the key parameters to test during product development, Impact of embedding a modem in an end product The quickest and simplest approach to M2M system development is to embed an integrated cellular module, an intelligent modem which provides a black box implementation of the physical and protocol layers. Modules from well-known suppliers such as Sierra Wireless, Cinterion and Telit will have been device or signalling behaviours. In a conformance test system, the test scenarios are limited to those specified by the 3GPP. These test systems do not facilitate in-depth testing and modification of the scenarios most relevant to any given application. And development of a dedicated test network is extremely expensive and time-consuming. Fortunately, there is now a better way. Wireless network simulation provides for the testing of an entire M2M system setup from the early stages of development. A network simulator supports detailed investigation of device and signal behaviour, provides complete freedom to simulate any kind of network protocol and environment, including those not provided by Powering your next design. Let us be your power expert. We understand that you don’t have the time to master every aspect of electronic design. As a leading manufacturer of power supplies we are here to collaborate with you to ensure your next project is a success. Dc-Dc Converters www.cui.com/PowerExpert Novum® Advanced Power Ac-Dc Power Supplies as will be shown below. tested and type-approved against test specifications published by 3GPP (3rd Generation Partnership Project – the cellular telephone industry’s standardsetting body). Certification of compliance with these specifications guarantees that a module conforms to the standard, just like a mobile phone. Before being embedded in an end product, therefore, the module offers highly reliable communications functions. In an M2M system, however, a module will typically operate alongside additional hardware and software in end products such as programmable logic controllers, electricity meters, credit card terminals and in-vehicle telematics and entertainment units. In addition, a central application environment handles the data flow from the M2M device, and takes decisions based on the type and value of the information it processes. The way in which the module is embedded in the end product can, then, give rise to communications malfunctions in the real world. It is disastrous if the first evidence of this unreliable behaviour comes when the device has already been released to the field. By developing test scenarios that mimic real-world use cases, and testing the M2M system’s behaviour in these scenarios in a controlled test environment, device manufacturers can, however, uncover and then rectify potential malfunctions before the device goes into production. In the past, developers used a variety of means to perform functional testing of M2M systems, for example testing prototypes in real live networks, using a conformance test system or developing a dedicated test network. All three methods, however, suffer from serious drawbacks. Testing in a live network only allows the testing of scenarios that can be found in the locations and at the times the prototype is tested. This makes it hard to repeat specific problematic test scenarios and to drill down into the causes of faulty www.electronics-eetimes.com Electronic Engineering Times Europe September 2013 33


EETE SEPT 2013
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