Machine-to-machine (M2M) cellular communications technologies may be particularly challenging, especially if they dont serve the purpose for which they were intended to transmit data for a specific device.
Ensuring good connectivity with M2M communications starts before devices enter the field. Here are three of the best ways to increase connectivity of a cellular M2M device.
1) Start with good design: Improving connectivity of an M2M device begins with proper design. Many M2M projects have failed altogether or werent able to pass certification because of poor antenna design. Antennas in todays M2M devices must be designed to support a wide range of cellular frequencies from 700 to 2,600 MHz to cover deployments around the world.
Parameters of antenna design should support efficiency of the radiated power and the power delivered to the antenna, the return loss of power reflected at the point of input, the isolation of power transfer between antennas, and correlation co-efficiency between antennas in a multi-antenna system.
Single Input Single Output (SISO) antennas are often used for radio, satellite, GSM and CDMA systems, and good performance for 2G and 3G cellular frequency bands is achievable with a single dual-resonance antenna, with return loss better than -6dB. But since 4G LTE mobile deployments require two antennas, the Multiple Input Multiple Output (MIMO) antenna system is preferred over SISO.
While the single-antenna design of SISO costs less and requires less port power, in M2M applications, particularly for LTE, MIMO antennas have distinct advantages, especially in multipath or line-of-sight conditions.
2) Use wireless Internet protocol (IP) best practices: When establishing a session, the M2M application code initiates a cellular transmission by sending a command through a USB or RS-232 port to a wireless IP radio module. After the module receives the command, it originates a call to the Mobile Switching Center (MSC) servicing the device at the local cellular network.
These sessions use a Point-to-Point Protocol (PPP) stack in establishing the connection. However, until an IP session is initiated, no actual IP path exists. To allow a network or server to initiate transmission of IP data to a device, applications designed for M2M should include Mobile-Terminated SMS messages, known as shoulder taps.
Data transmission over wireless IP is a choice between User Datagram Protocol (UDP) and Transmission Control Protocol (TCP). UDP costs less than TCP, but it is also less reliable. UDP is effective for transmitting small amounts of data within a network, while TCP is more suitable for error-free transmissions of data larger than a few kilobytes in size.
3) Include firmware updates in development and ensure proper testing: Most devices require at least one firmware update during their life cycle. Since these are usually remotely deployed, its important that the update capability for firmware be included as part of a devices development. For example, some devices may require additional hardware to hold active and new images of the firmware.
Proper testing is also important to ensure the best connectivity. Testing performed in the development stage needs to be performed under anticipated conditions that are able to gauge reaction to blocked or delayed transmission and poor signal locations.
During final testing for certification, tests to stress the interaction between the device and the server should also be conducted. These tests help to reveal unusual behaviors, such as delayed responses from a server.
Proper installation also improves connectivity by eliminating issues before a device begins transmitting. Since many devices are installed in the field by personnel who are not always familiar with the way cellular products work, its important that installation procedures be written in clear, concise language. Installation procedures should also anticipate errors by the installer. For example, if the installation in a vehicle cab that is made of non-conductive plastic must include mounting of the antenna to a metal backplane thats included with the device, that should be clearly stated in the instructions.
An M2M provider that owns and operates its own cellular network dedicated solely to M2M is able to improve your ability to stay connected. Having a dedicated network means your transmissions wont be competing with consumer traffic, which provides for higher efficiency in mission-critical transmissions. M2M providers that use both CDMA and GSM technologies also offer better connection capabilities by allowing devices to always use the strongest signal available.
The best connectivity with M2M starts before devices even enter into service through good design, development and testing.
Aeris Communications provides benefits across all these factors. To find out many benefits of Aeris, click here.
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