5G Test Technologies: Signalling and RF/Protocol Tests
As described above, communications terminals, such as smartphones, incorporate integrated circuits (ICs) with peripheral wireless communications functions described as a “chipset”, peripheral circuits such as filters, antennas, etc., and other parts. Thanks to the modular chipset, developers can design smartphones without needing to be overly conscious of fine details such as the exchange of command messages for connecting with base stations, RF signal control, etc. Moreover, the necessary performance can be implemented efficiently at smartphone design by using circuits and parts specifically for the target communications method. Conversely, chipset developers must test their designs to assure correct control of RF signals in accordance with complex message protocols. Developers of RF circuits and parts must test their designs to assure optimized RF signal processing for the target communications and to achieve the specified performance.
Taking chipset development as an example, it is possible to push forward with separate development of the message protocol and RF control sections. However, ultimately, both these sections must be combined in a single chipset, and correct wireless communications and control between the terminal and base station must be tested. When testing the latest communications, such as 5G, it performs the Interoperability Development Test (IoDT) at the pre-silicon stage to test connectivity with other infrastructure manufacturers, such as base stations. And also it requires a measuring instrument capable of simulating the messaging protocol in the laboratory such as a base station simulator because there are few extant commercial 5G base stations.
Even design of peripheral circuits, parts, module chipsets, terminals, and communications equipment requires testing of the finished product combining all parts to assure that the specified performance is achieved. Though the function of the message protocol part standardized by 3GPP is implemented in the chipset, when carrier-specific application services are offered, sometimes it is necessary to add special non-3GPP protocol tests for carrier-specific terminals to confirm that the message protocols are following the requirements at the terminal application level.
When developing and using these 5G chipsets, peripheral circuits, and parts in 5G products for different markets, such as 5G smartphones, 5G communications modules, automotive, IoT, etc., it is critical to test operation and performance under communications control (Signalling check under call processing) with a base station simulator mimicking near-to-real operating conditions.
Consequently, analysis of message protocols and evaluation of RF performance requires a measuring instrument that can connect to, communicate with, and control the chipset correctly for both RF and message protocols.