Generalized Polarization-Space Modulation

Abstract

A novel generalized polarization-space modulation (GPSM) is proposed for polarized multiple-input multiple-output (MIMO) systems with a limit number of radio frequency (RF) chains. In the spatial domain, multiple dual-polarized (DP) transmit antennas are activated, and then combinations of those indices are used to convey information. While in the polarization domain, depending on the random input bits, only one polarization state is selected for each active DP transmit antenna to transmit information following the rule of the polarized shift keying. At the receiver, the maximum likelihood detector is employed as a benchmark to detect information bits being used to select the polarization state and activated DP antennas. In the detector, imperfect channel state information (CSI) is taken into account. Two less computationally complex detectors, i.e., a linear detector and a sphere decoding (SD) detector are proposed to relieve the computational burden. Sacrificing the average bit error probability (ABEP) performance, the proposed linear detector can reduce the computational complexity significantly. The proposed SD detector can achieve the optimum ABEP performance, while reducing computational complexity by reducing the search space. A closed-form union upper bound (UUB) on the ABEP of the GPSM system with imperfect CSI at the receiver is analytically derived and validated through simulations. From the UUB, a loose asymptotic bound on the ABEP, which sheds light on deriving the diversity gain and the coding gain, is derived. Numerical results show that the signal-to-noise ratio loss caused by increasing the number of transmit antennas is less than 3 dB while the spectral efficiency is increased by 7 b/z/Hz. Therefore, the GPSM can be a promising candidate of down link massive MIMO systems to achieve a high spectral efficiency with a limit number of RF chains.

A reconfigurable intelligent surface with integrated sensing capability

“…In such a system, the proposed design can also sense wideband incident beams. On the other hand, while the proposed work only examined the case of single polarized waves, one can envision scenarios that information is multiplexed in the polarization or angular momentum 63,64 . In such cases, depending on the intended applications, we can use polarization independent or polarization sensitive metamaterial elements, such as the geometries proposed in [65][66][67][68][69][70] .…”

Reconfigurable-Metasurface-Aided Multi-State Generalized Polarization-Space Modulation for Next-Generation Wireless Communications

“…, x P −1 , each with an average symbol power E[|x p | 2 ] = 1. We represent the polarization state of x p,n SA -the n SA -th element of x p -using Jones vector in a right-handed Cartesian coordinate system [5,9] as…”

“…Very recently, generalized polarization-space modulation (GPSM) [6] has been proposed as an extension of PolarSK for multiple-input multiple-output (MIMO) systems with a limited number of radio frequency (RF) chains [9]. It allows concurrent activation of multiple DP Tx antennas with one polarization state per antenna per time slot.…”

“…1. Schematic of the transmit index mapping approaches for conventional (a) PolarSK [5] (single DP antenna with only polarization states used for mapping) (b) SM [4] (multiple antennas without any polarization diversity) (c) DP-SM [7] (only two polarizations per antenna) (d) GPSM [9] (multiple polarizations per antenna), and our proposed (e) RMTS-enhanced GPSM transmitter. The user message is given by the sequence of bits b 0 , b 1 , • • • .…”

“…In this paper, we introduce the RMTS implementation of GPSM to achieve a reduced form-factor that is optimized to provide maximum polarization tunability. Further, unlike the conventional DP phased array system of GPSM [9] that requires a MIMO Tx antenna with multiple RF chains and produced only two polarization states, our proposed design requires only single RF feed source and yields more than two polarizations. This reduces the cost and RF complexity of the transceiver.…”