Detailed decryption of Huawei’s WLAN equipment RF and baseband chip patents

With the development of wireless technology, wireless local area network (WLAN) devices have been able to support multiple frequency bands. WLAN devices that support multiple frequency bands usually include: multiple antennas, multiple radio frequency chips, and a baseband chip.

Wherein, the baseband chip is respectively connected with a plurality of radio frequency chips, and the plurality of radio frequency chips are respectively connected with a plurality of antennas through radio frequency wirings. However, the RF wiring loss of the current WLAN equipment is relatively large, which affects the performance of the WLAN equipment.

To solve this problem, Huawei applied for an invention patent (application number: 202010889734.5) on August 28, 2020 called “Radio Frequency Chip, Baseband Chip and WLAN Equipment”, the applicant is Huawei Technologies Co., Ltd.

According to the relevant information currently disclosed in the patent, let us take a look at this technical solution.

The above figure is a schematic diagram of the structure of the WLAN device invented in this patent. The device mainly includes components such as an antenna 11, a radio frequency chip 12 and a baseband chip 13. The radio frequency chip is respectively connected to the baseband chip and the antenna. The baseband chip includes a baseband processing circuit and an intermediate frequency processing circuit, and the baseband processing circuit is mainly composed of a baseband circuit, a medium access control (MAC) circuit, and a physical layer (PHY) circuit.

In the process of receiving the signal by the WLAN device, the antenna receives the radio wave and converts the radio wave into a radio frequency signal, and then sends the converted radio frequency signal to the radio frequency chip. process, and send the processed IF signal to the baseband chip. The baseband chip obtains the data signal according to the intermediate frequency signal, and outputs the obtained data signal.

When the WLAN device sends a signal, the baseband chip generates an intermediate frequency signal according to the received data signal, performs signal processing on the obtained intermediate frequency signal, and sends the processed intermediate frequency signal to the radio frequency chip. The radio frequency chip performs signal processing on the intermediate frequency signal, converts the processed intermediate frequency signal into a radio frequency signal, and sends the converted radio frequency signal to the antenna. Finally, the antenna converts this radio frequency signal into radio waves and sends it.

As shown in the above figure, it is a schematic diagram of the structure of the radio frequency chip in the above scheme. The radio frequency chip includes a signal generation circuit 121, three radio frequency transceiver circuits 122 and three intermediate frequency transceiver circuits 123. Each radio frequency transceiver circuit corresponds to an intermediate frequency transceiver circuit one-to-one. connect. The first signal generating circuit is used for generating a first radio frequency local oscillation signal, and the second signal generating circuit is used for generating a second radio frequency local oscillation signal. The frequency band to which the first RF LO signal belongs is different from the frequency band to which the second RF LO signal belongs. For example, the first RF LO signal belongs to the 2.4GHz frequency band, and the second RF LO signal belongs to the 5GHz frequency band.

Because two of the three radio frequency transceiver circuits can convert the received signal between the intermediate frequency signal and the radio frequency signal according to the first radio frequency local oscillator signal and the second radio frequency local oscillator signal respectively, and the first radio frequency signal The frequency band to which the local oscillator signal belongs is different from the frequency band to which the second radio frequency local oscillator signal belongs. Therefore, the radio frequency chip can be made to support at least two frequency bands, that is, the radio frequency chip can transmit and receive radio frequency signals of at least two frequency bands.

When such a radio frequency chip is used in a WLAN device, since the radio frequency chip can transmit and receive radio frequency signals of at least two frequency bands, the radio frequency chip can be connected to the antenna used for transmitting and receiving radio frequency signals of the at least two frequency bands, so that the radio frequency chip can be used for transmitting and receiving radio frequency signals of the at least two frequency bands. The antenna of the radio frequency signal of this frequency band does not need to be connected to two radio frequency chips that only support a single frequency band respectively.

In this way, when setting the RF wiring between the antenna and the RF chip in the WLAN device, the RF wiring can be flexibly set according to the deployment position of the antenna and the RF chip, which is beneficial to reduce the length of the RF wiring between the RF chip and the antenna , thereby reducing the chance of crossover between RF traces.

Finally, as shown in the above figure, it is a schematic diagram of the structure of the baseband chip in the patent. The baseband chip mainly includes a baseband processing circuit 131 and a plurality of intermediate frequency processing circuits 132 . The plurality of intermediate frequency processing circuits include a first intermediate frequency processing circuit and a second intermediate frequency processing circuit, and the working frequency band of the first intermediate frequency processing circuit is different from that of the second intermediate frequency processing circuit.

In the process of sending signals, the baseband processing circuit can generate a plurality of baseband output signals based on the received data signal, and distribute the plurality of baseband output signals to a plurality of intermediate frequency processing circuits, and the intermediate frequency processing circuit converts the received baseband output signals It is an intermediate frequency signal, and the converted intermediate frequency signal is processed in the time domain, and the processed intermediate frequency signal is output through the baseband chip pin J.

In the process of receiving the signal, after receiving the intermediate frequency signal from the baseband chip pin J, the intermediate frequency processing circuit can perform signal processing on the intermediate frequency signal in the time domain, and convert the processed intermediate frequency signal into a baseband input signal. Then, the converted baseband input signal is sent to the baseband processing circuit, and the baseband processing circuit processes the baseband input signal sent to it by the intermediate frequency processing circuit to obtain the data signal, and finally outputs the obtained data signal.

The above is the RF and baseband chip solution invented by Huawei and applied to WLAN equipment. This solution uses multiple RF transceiver circuits and IF transceiver circuits to cooperate with each other, which can solve the problem of large RF wiring loss of WLAN equipment, resulting in the performance of WLAN equipment. issue of impact.