The rapid increase in number of used carriers and MIMO streams in modern LTE devices introduce new challenges when measuring radio performance. This white paper gives an introduction to Over-the-Air (OTA) measurements of such devices and what to consider when moving from a conducted measurement to measurements in a multipath faded OTA environment. It includes configuration examples using Bluetest's RTS65 reverberation test system and the
Reverberation Chamber Technology
A reverberation chamber is essentially a large reflective enclosure, or cavity, that will resonate when signals are introduced into it. These resonances makes microwave signals reverberate, similar to how sound reverberate in an enclosure.
As signals bounce off the walls and objects in the chamber they interfere. This constructive and destructive interference of multiple signal reflections form cavity modes. A reverberation chamber adds special stirring functions to move the points of constructive and destructive interference around in the chamber. By proper stirring, multipath fading effects can be distributed in a statistically well defined and repeatable way inside the chamber. This multipath fading environment is particularly appropriate to today's small, multi-purpose and high data rate wireless devices.
A radio propagation channel describes how the environment can affect the radio signal as it travels between the transmitter and receiver. As devices move and signals bounce off of buildings or vehicles, changes in frequency, phase and power occur. Wireless engineers in the industry broadly model these effects with a few main variables such as:
Internet of Things (IoT) and Machine to Machine or M2M communication is an application area quickly growing in importance both in the professional and domestic market. The professional segment includes different kinds of wireless metering, wireless diagnostics and supervision, while the domestic market focuses on smart home appliances. Together they include devices with a wide range of sizes and shapes increasing the need for flexible test solutions capable of testing small as well as larger wireless devices.
As the variety of wireless devices and wireless connections in a car increases, there is a corresponding increase in the need for testing to ensure good functionality and performance. Automotive engineers are finding that Bluetest reverberation test systems are often the most convenient solution for understanding the effects of wireless devices in, around and embedded in vehicles.
Although WLAN has been around for many years it has during the last couple of years grown rapidly in importance, driven mainly by the introduction of WLAN into mobile devices and operators offloading data from their cellular networks. Another force contributing to the strong growth is the trend to have “everything” connected, for example home appliances as well as different types of metering and sensors.
We are in the forefront of providing measurement solutions for the newest communication systems. We don’t let you wait for measurement solutions supporting technologies that is introduced now. A proof of that is our introduction of MIMO functionality already in 2009 and support for 2 component carrier aggregation (2CC) in 2013.
It is common nowadays to add a cover to your mobile phone, both for protection and esthetical reasons. They are available in many different stores including the mobile operator branded stores. The material and form varies considerably from one cover to another. You can get everything from plastic and rubber covers to silicon or metal. Of course the different materials have pros and cons. Some are more protective, even against the delivery of data. The question that follows is; how does a cover affect the performance of the antenna?
For the last couple of decades, reverberation technology was solely used as a tool for engineers specializing in electromagnetic compliance (EMC) testing. Bluetest innovations have transformed this technology into a powerful solution tuned to the needs of current wireless developers. They are the next generation of over-the-air (OTA) test systems that bridge the testing gap between conducted and drive test methods.
Multipath fading has for many years been a problem for mobile communication engineers, to be overcome by designing systems that have sufficient signal-to-noise ratio (SNR) or signal-to-interference ratio (SIR) margins. The fading is caused by multiple reflections in walls and ceilings (indoors) or cars and buildings (outdoors) that add constructively or destructively at the location of the terminal or base station antennas.