A Novel Multiple Access Technique Based on Antenna Radiation Pattern Modulation

摘要

This paper extends Beam Angle Shift Keying (BASK) transmission technique into a multi-user version called Beam Angle Multiple Access (BAMA). BASK is a recently developed antenna beam pattern modulation scheme where at the transmitter, the block of information bits is mapped into a spatial symbol selecting the beam for the unmodulated carrier signal. At the receiver, after specular reflections, the carrier signal arrives at the receiver from one direction over the duration of the spatial symbol and the receiver antenna array is used to detect single-user data through angle-of-arrival (AOA) estimation. In this paper, multiple access on the uplink is achieved by assigning subsets of beams to individual users signaling with BASK. At the base station, over the duration of the spatial symbol the receiver decides on a subset of possible multiple AoAs corresponding to synchronized spatial symbols from different users. Specifically, we propose a maximum-likelihood (ML) detector which can successfully decode incoming data from multiple simultaneous BASK transmissions by deploying a linear array of receive antennas. Unlike in spatial division multiple access where a fixed beam arrangement is used, BAMA detects the beams used by multiple users on a symbol-by-symbol basis. In the proposed scheme, the management and selection of beams are crucial with respect to capacity of the system. It is demonstrated that the detection reliability of the spatial symbols in BAMA is determined by the number of antennas used at the receiver and the actual angles of signal arrival.