Whose baseband chip is Xiaomi mobile phone?

It depends on the model. Different models of Xiaomi mobile phones will use different baseband chips. Although Xiaomi's 3TD CPU uses NVIDIA chip and Unicom's CPU uses Qualcomm chip, Xiaomi's 3TD CPU uses Spreadtrum sc8803G, and Samsung's Geshi series, Note series, HTC ONE and other models are also in use. Mi -3 communication version and telecom version use Qualcomm's baseband chip.