With the CTIA MIMO OTA test plan v1.0 released in July 2015, and the corresponding Laboratory Assessment and Validations Requirements (AVRD) document released shortly after, it is time to proceed to the next-steps toward mandating this plan for evaluating wireless device performance.
As test system providers will soon be validated, individual labs interested in becoming a CTIA Authorized Testing Laboratory (CATL) must submit their AVRD package in due time. Spirent has worked with the main anechoic chamber vendors to ensure the spatial channel model meets expectations, though final passing criteria is still being worked out in CTIA’s MIMO OTA Subgroup and 3GPP RAN4. Spirent is also working with chamber providers to ensure that all future CATLs can meet the specified Measurement Uncertainty (MU) limits (the CTIA plan establishes a limit as to how large the measurement uncertainty can be for a particular system configuration). This greatly simplifies the certification process for individual labs allowing them to select from the CTIA-authorized equipment list for approved test system configurations rather than validating the spatial channel model on their own. Due to unavoidable variances in chamber construction, some deployment-specific aspects that impact the MU still have to be provided by each lab to ensure the MU target is met. When enough third-party labs become CATLs, the MIMO OTA test plan v1.0 will become mandatory. With many labs out there already having the equipment needed to implement v1.0, the time to get the number of authorized labs needed to make the test plan mandatory should be minimal.
While the first version of the MIMO OTA test plan is undergoing its finalization process, CTIA is already working on future releases of this test plan to incorporate minor corrections and enhancements. Such enhancements may include additions to the Multi-Probe Anechoic Chamber (MPAC) technique or the introduction of the Reverberation Chamber plus Channel Emulator (RC+CE) configuration to evaluate cell edge performance (cell transmit diversity with or without device receive diversity). CTIA standards are contribution-driven and adopted based on consensus, so variation in the schedule for each future release is to be expected based on the different points of view of each participating party.
None of the currently planned CTIA MIMO test plan releases aim at adding support for testing techniques that address advanced technologies such as carrier aggregation, WiFi, LTE Unlicensed, and WiFi offloading, configurations with MPAC or RC+CE, or support of larger probe counts for MPAC. The industry recognizes significant business and market drivers to commercialize these evolving technologies and rather than waiting for standards to be released, operators are defining their own test plans and labs are getting equipped with the test infrastructure necessary to deal with the these complex OTA applications now.
MIMO OTA Testing Solutions from Spirent
In the MIMO OTA testing arena, Spirent actively participates in industry standards committees and contributes regularly to the advancement of state of the art testing techniques. As an experienced OTA equipment vendor, Spirent is uniquely positioned to help our clients through the channel emulation aspects of the CATL application process, as well as other key test areas. Spirent’s MIMO OTA testing solutions encompass techniques adopted by standards bodies and by labs requiring advanced R&D using high-density, space-conscious, and cost effective equipment. The Vertex Channel Emulator, Spirent’s newest entry into the field, is a versatile platform that offers unprecedented scalability while supporting emulation of a large number of channel models and high-density applications such as MIMO OTA.