Low Density Signature Based Packet Access with Phase Only Adaptive Precoding

Abstract

This paper proposes a low density signature-based packet access with phase only adaptive precoding. The proposed access allows multiple user terminals to send their packets simultaneously though only one antenna is put on terminals and on an access point, in order to increase network throughput. The proposed phase only adaptive precoding improves the transmission performance by rotating the transmission signal phase. This paper proposes a criterion that defines the optimum rotation angle, and actual two techniques to estimate the angle. When 6 packets are transmitted in 4 time slots, the proposed adaptive precoding attains about a gain of 4dB at the BER of 10^{-4} in a single input single output Rician fading channel, i.e., overloading ratio is 1.5.