Bluetooth Device Test Solution

Bluetooth device testing is carried out on the basis of Bluetooth product technical specifications, including interoperability testing, conformance testing, etc. The Bluetooth device test should first carry out the formulation of the test plan, and then carry out operations such as protocol consistency, underlying hardware modules, and interoperability tests.

1. Explanation of Bluetooth test mode

The purpose of testing Bluetooth devices is to ensure the final experience of excellent users, realize the optimal functions of Bluetooth devices, calibrate and test the performance of subsystems and components in Bluetooth devices, test the main environment and screen out defects. materials to ensure the quality of Bluetooth devices.

According to the bluetooth technical specification, the definition of the application specification and the formulation of the test mode of the protocol are respectively carried out, such as the serial port emulation protocol, the service discovery protocol, etc. According to the specific female-public mode, each layer of protocol under the operation coordination mechanism is set for each functional element, and the entire Bluetooth protocol system is divided into three levels: the middle layer, the bottom layer, and the high-end layer, which are respectively the bottom hardware module and the middle protocol layer software. modules and high-end applications.

Among them, the intermediate protocol layer includes adaptation protocol and logical link control, the underlying hardware part includes baseband, link management layer and wireless frequency hopping, and the high-end layer includes the application framework composed of telephone communication protocol, serial emulation protocol, and service discovery protocol. The test of the underlying hardware module function is particularly important, mainly through the compatibility test of the wireless baseband layer and the establishment of a test mode.

The Bluetooth device test module includes the test device and the device under test, and builds a piconet. The test process is fully controlled by the master device. The device can use DUT as the device for Bluetooth transmission and reception, and use the additional measurement device TESTER as the system composition. The test process is: initialize the independent baud rate, click start, disconnect the serial port, receive data, and start to execute the command to test the Bluetooth device.

In the test, the activation was performed locally using the wireless interface, the software ran the wireless interface, and the hardware took care of the activation. When the DUT is commanded to perform the activation operation, TESTER enters the test mode and issues a link management protocol command. After the activation command is received, it enters the test mode and the DUT returns to complete all standard operations. For the unfinished LMP-AC-CEPTED activation command, the software interface can be used to continue the activation operation until the connection with the TESTER is established, and then the paging scan and inquiry scan can be performed through the DUT.

After the control operation of the control interface is performed using the LMP command, the test is passed. At this time, the DUT has not been standardized, but the hardware interface still exists, and the Bluetooth device does not need to execute the command in the test mode. After returning the LMP-NOT-ACCEPTED instruction, the DUT enters the test mode. After receiving the control instruction, the LMP instruction and processing power control are allowed to appear, and the standard program is used for testing. The power can be debugged during the process. By exiting the test mode, the instruction Set in the scheme to force the DUT out of the test module.

The test scheme of the Bluetooth device includes the POLL grouping at the sending end, the periodic transmission of the piconet composed of TESTER, the testing of the sending end and the test grouping in the DUT unit, which works as the master unit, and the test device uses the TX time slot to perform the sending operation. The POLL group control command is used to operate, and the TX time slot is used to operate the unit. After the sending command is started, the unit can pre-define the interval through the unit wheel and set it to a fixed value, so that the device under test can send data regularly.

The pseudo-random sequence refers to the fact that the shift register uses a uniform sequence as the random sequence of the transmission packet, the longer zero sequence is 8, and the sequence becomes 511 bits. The descending frequency hopping sequence uses the complete fast wireless test to perform five timing frequency hopping in the frequency range, and the channels are 0, 23, 46, 79, and 95 respectively. The bit pattern is sent and stopped in the form of a pseudo-random code, starting from a sequence of 1, alternating 1010, alternating 1111, 0000, 1111, 0000, and the sequence can also start from 0. Frequency selection includes European and American frequency hopping, Japanese frequency hopping, Spanish frequency hopping, French frequency hopping, and frequency hopping in descending order.

The format of the test packets is grouped using forward error correction codes, including AUX1. HV3, DH1, 3, 5. Divided into payload length format, packet format, etc. When sending in test mode, TESTER defines the payload length through appropriate settings, and the control of transmission parameters meets the requirements of the baseband specification, and test sending can be performed.

Switching between different frequency settings, after receiving a new frequency band message, DUT starts to switch after receiving the message.

For power control, use the conventional LMP command to test and control the adaptive power, use the drunk power for transmission, and increase or decrease the power according to the received command.

After decoding the device under test, the conventional baseband grouping method is used for transmission between the next TX time slot, and the effective load is carried out in the TX time slot loopback test, and the pseudo-random sequence code of enabling or stopping is sent back, and the same grouping is used Then add noise in the test equipment.

If the test mode control information is included in the packet, the instruction will not be executed and will not be returned to other packets when other LMP instructions are ignored. It is allowed to use the error correction code FEC for encoding and decoding in the forward error correction processing test. The grouping of test equipment uses bit error rate for forward error correction testing.

In the case of CRC invalidation, the payload is used for grouping, and the packet carrying the CRC can be returned by the payload. If the header verification fails, the ARON can return a NAK by using a NULL packet containing the ARQN bit, and may not respond if the synchronization header is not detected.

2. Bluetooth test control interface

The Bluetooth technical specification includes two documents, the application framework and the core protocol. The former specifies the definition of each layer of Bluetooth communication protocols, and the latter specifies the product applications implemented by the protocol.

All Bluetooth components are tested with the conformance test protocol, and the protocol of the object under test is tested in the peripheral product. After the high-level device UT implements the underlying functions, the protocol is verified and implemented through testing. In order to avoid the change of each measured object and test system due to different situations, the mandatory test method of the standard control interface can be used to access the test equipment, and the method of uniformly testing the high-level interface can be used, and the IUT uniformly supplied by the manufacturer can be used. The adapter performs hardware and software operations.

In the verification of the baseband layer, logical link control and adaptation protocol interface, and link management layer protocol, the interface between the test equipment and the SUT used includes: TCI-L2CAP interface, which can be used after verification by the SUT , events and commands can be defined through the service interface, which can be converted into messages in the same format as commands and HCI events. The TCI interface is used for the host control interface, and is used as the interface of the test system through the verification of the link management layer and the link control layer. The test system realizes event access with the upper layer by sending HCI event access commands and HCI commands. The test equipment used is located in the transport layer channel, including physical channel and software channel, because the manufacturer is responsible for the operation of the software and sends data to the device.

3. Bluetooth protocol stack conformance test

The test is checked and given with the entity through the intrinsic form of the protocol. The internal specifications are consistent with each other, and can only be tested after passing the description of the specification and the detection of the output form.

The structure of the L2CAP conformance test includes three components: the conformance test system, the test control software and the tested object. The execution test system is connected through the test control interface in the bluetooth device, and the test control software performs an air interface to the bluetooth transmitting device in the object under test. The recommended physical transport layer of TCI is the specified transport layer of HCI, including RS232, UART and USB. The test system sends L2CAP system commands to the object under test. After the object under test receives the command, the upper layer of the test system drives through the physical bus driver and the L2CAP driver, and the underlying object under test implements L2CAP data after processing. grouping.

The test control software includes three components: L2CAP firmware, adapter and physical bus. The test control software is adapted through the interface. The data in the test control software is sent by the physical bus. After reaching the upper level of the test system, the data is received, and the firmware encodes and decodes the data. The interface in the adapter performs IUT adaptation, and finally realizes the test of the object under test according to the software of the Bluetooth master protocol.

Summarize

With the rapid development of information technology, new types of smart terminals integrate computing and communication. New devices represented by smart terminals and smart phones have gradually replaced traditional desktop computers and notebooks, which are smaller in size, lower in power consumption, and With a variety of communication means, such as Bluetooth technology, for information interaction. As one of the main short-distance and low-power wireless communication technologies, Bluetooth technology has been widely used in the field of transmission and information exchange, and has become the cutting-edge technology of wireless communication. The purpose of designing the Bluetooth test program is to realize mobile Wireless connection between equipment and fixed equipment, and achieve the goal of low cost and simple construction. This paper systematically analyzes the implementation process of the bluetooth test scheme through the elaboration of the conformance test method of the bluetooth protocol and the test mode of the bluetooth device.

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