A cost-effective approach for engineers who need to generate real-world cellular interference signal conditions to validate LTE system performance is being provided by cooperation between Agilent Technologies Inc. and Nomor Research GmbH (Munich, Germany).
Realistic emulation of the uplink inter-cell interference generated in a multi-cell LTE network is ensured through use of system-level simulation and complies with 3GPP and NGMN simulation methodology. The signal is physically generated by an Agilent MXG signal generator and can be coupled into the receiver path at the base station.
The test solution is currently being used by most infrastructure vendors participating in global LTE field trial activities and is now is being made widely available. A set of default interference files for representative scenarios is provided at no cost and may be used with any Agilent MXG signal generator. An extended pack of interference files for alternative deployment scenarios and customized parameter settings is available on request.
“Performance evaluation of LTE systems must be done under realistic interference conditions,” said Moray Rumney, lead technologist with Agilent. “Until recently, the only way to do this involved expensive and time-consuming deployment of large numbers of mobile devices in adjacent cells. With this new method, a near equivalent interference environment can be created at the base station representing the combined interference from hundreds of mobiles in adjacent cells.”
Eiko Seidel, chief technical officer of Nomor Research added, “The newly standardized orthogonal LTE uplink access scheme has changed the uplink interference characteristics in such a way that traditional Gaussian noise methods for emulating interference are no longer suitable for realistic performance testing.”
“Inter-cell interference in today’s LTE networks is highly variable with respect to time and frequency, and is dominated by a small number of interferers per resource block, causing unexpected behavior for adaptive algorithms that respond to inter-cell interference. Only realistic modeling of inter-cell interference offers infrastructure manufacturers and operators a tool for testing advanced base-station scheduling algorithms and for quantifying the true performance of LTE base-station equipment,” said Seidel.