Research On Radio Frequency Testing Of Bluetooth Low Energy Based On CC254x Development Board

Bluetooth has been widely applied in various types of mobile communication devices as a short-range wireless communication technology. Bluetooth specification has developed from classical type(Basic Rate and Enhanced Data Rate) to today's Bluetooth Low Energy(BLE) which has very low power consumption and very long standby time. During the rise of Io T(Internet of Things) technology, more and more wearable devices equipped with BLE technology emerge.In order to guarantee high interoperability of different Bluetooth devices manufactured by different plants, Bluetooth SIG constituted comprehensive Bluetooth testing protocols. Bluetooth qualification and certification by the Bluetooth SIG is required for many products using Bluetooth wireless technology before entering the market, and it need to test the function and performance of the product. Bluetooth qualification generally needs to pay a certain fee and the process is complex and spents long time, therefore, we can use third-party test equipment to complete the BLE products' pre-certification testing to reduce time and costs for product R&D. Bluetooth RF conformance tests include protocol conformance testing, profile conformance testing and profile interoperability testing. RF conformance testing mainly examine the performance of RF physical layer of the Bluetooth, it is the foundation of all other tests. RF characteristics of BLE has slight difference with the traditional Bluetooth‘s. The BLE RF testing was studied in this paper.Development board has features of low cost, abundant resources and convenient debugging, it is often used for secondary development of the product. This article researches BLE RF testing based on Texas Instruments' single-mode BLE CC254 x development board. Large Bluetooth testing devices emphasize on the conformance testing and interoperability testing. They are expensive and complicated in implementation and low-efficient in application testing and are not suitable for some companies to develop products. Therefore, a method to combine small test instruments with development board to form a data transceiver testing system was proposed in this paper, and the RF testing of CC254 x development board was achieved based on BLE RF test specification.The technology features and architecture of BLE was introduced in the first part, focusing on BLE RF characteristics and direct test mode(DTM), followed by a detailed study of BLE RF test specification. Then the method for achieving BLE DTM of the CC254 x development board was analyzed. It makes CC254 x development board entering the DTM immediately after power supplied by modifying BLE protocol stack application-level code in software layer and connecting hardware circuit. Finally, according to testing process in BLE RF test specification, sending corresponding test commands through the serial debug assistant, using N9000 A spectrum signal analyzer and W9081 A test component to complete all the transmitter test items, and a N5182 B signal generator and N7606 B Bluetooth test software which is running on the computer to complete part of the receiver test items of the CC254 x development board. These BLE RF test results meet expectation and have higher stability and accuracy, and the test progress spent less time. The BLE RF test methods and test procedures based on CC254 x development board provide meaningful reference and guidance for other single-mode BLE products' RF test in research development and manufacturing stages.