GBU1004 is a 4G LTE multi-mode digital baseband chip manufactured by Yangjie. This chip is designed for small cell base station front-end processing applications and supports 3GPP R8/R9-based uplink/downlink data transmission. It is equipped with a dual core network processor that allows for simultaneous operation of multiple channels. The chip supports a variety of modulation schemes, including 512QAM, 16QAM, QPSK, BPSK and GMSK. It also comes with support for Q-boosting technology, which provides high-bandwidth access using multiple antennas. Additionally, it provides features such as key-assisted handover, multi-user MIMO, data rate boosting, and more.