Adaptive Tx skirt suppression for multi-radio in-device coexistence

With the proliferation of multi-standard mobile devices, in-device coexistence (IDC) has become a key challenge in the design of modern radios. Typical IDC use cases involve radio transmitters (aggressors) that are interfering with radio receivers (victims) collocated on the same device. Isolation of the sensitive receiver from high power transmitters on the same device poses major difficulties due to insufficient frequency separation between the aggressors and their victims. In this paper, we present an adaptive approach to suppress unwanted out-of-band signal power (i.e. TX skirt)from the aggressor to minimize desensitization at the victim. The proposed method relaxes off-chip filtering requirements and reduces guard band spacing, leading to a low cost integrated solution for multi-standard radios. To highlight the effectiveness of the proposed algorithm, we have demonstrated greater than 30 dB improvement in signal-to-interference ratio (SIR) enabling the coexistence between Band-40 LTE and 2.4GHz Wi-Fi radios on the same device.