Transmit Beamforming for Ambient Backscatter Communication Enabled Wireless Body Area Network in Multiuser MISO System

Wireless Body Sensor Network (WBAN) is a promising technology which can provide pervasive E-health services. However, the power consumption of wireless communications in WBAN greatly restricts its applications. Recently Ambient Backscatter Communication (AmBC) technology has been introduced to realize ultra-low power passive wireless communication, thus it is highly desirable for WBAN. In this paper we consider that AmBC, powered by a multi-antenna Base Station (BS), is incorporated in WBAN to achieve ultra-low power intra-WABN communication. To fully exploit the potential of the AmBC in WBAN, the transmit beamforming at BS, the AmBC information symbol period as well as the transmission time allocation are jointly designed, taking into account Quality of Service (QoS) requirement of WBAN and cellular users, and BS power budget. The formulated optimization problem is highly nonconvex and very challenging to solve. To tackle this issue, we employ Inner Approximate (IA) framework to reformulate the original problem and solve it in an iterative manner. Finally, numerical results are provided to show the effectiveness of the proposed algorithm under various of system parameters settings.