Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí hóa hoc quốc tế đề tài : Average minimum transmit power to achieve SINR targets: performance comparison of various user selection algorithms | Salim and Slock EURASIP Journal on Wireless Communications and Networking 2011 2011 127 EURASIP Journal on . http content 2011 1 127 Wireless Communications and Networking a SpringerOpen Journal RESEARCH Open Access Average minimum transmit power to achieve SINR targets performance comparison of various user selection algorithms Umer Salim1 and Dirk Slock2 Abstract In multi-user communication from one base station BS to multiple users the problem of minimizing the transmit power to achieve some target-guaranteed performance rates at users has been well investigated in the literature. Similarly various user selection algorithms have been proposed and analyzed when the BS has to transmit to a subset of the users in the system mostly for the objective of sum rate maximization. We study the joint problem of minimizing the transmit power at the BS to achieve specific signal-to-interference-and-noise ratio SINR targets at users in conjunction with user scheduling. The general analytical results for the average transmit power required to meet guaranteed performance at the users side are difficult to obtain even without user selection due to joint optimization required over beamforming vectors and power allocation scalars. We study the transmit power minimization problem employing non-linear dirty paper coding DPC technique and with various user selection algorithms namely semi-orthogonal user selection SUS norm-based user selection NUS and angle-based user selection AUS . Starting from the derivation of a transmit power upper bound that becomes tight for large SINR targets the average minimum transmit power is derived for NUS and SUS for any number of users. For the special case when only two users are selected we further derive a similar expression for AUS and a power lower bound which may serve to benchmark the performance of any selection scheme. Simulation results performed under various settings indicate that SUS is by far the better user .
