Transmission Through Large Intelligent Surfaces: A New Frontier in Wireless Communications

Abstract

In this paper, transmission through large intelligent surfaces (LIS) that intentionally modify the phases of incident waves to improve the signal quality at the receiver, is put forward as a promising candidate for future wireless communication systems and standards. For the considered LIS-assisted system, a general mathematical framework is presented for the calculation of symbol error probability (SEP) by deriving the distribution of the received signal-to-noise ratio (SNR). Next, the new concept of using the LIS itself as an access point (AP) is proposed. Extensive computer simulation results are provided to assess the potential of LIS-based transmission, in which the LIS acts either as an intelligent reflector or an AP with or without the knowledge of channel phases. Our findings reveal that LISbased communications can become a game-changing paradigm for future wireless systems.Index Terms-Beyond massive MIMO, error probability analysis, large intelligent surface (LIS), signal-to-noise ratio, smart reflect-array, software-defined surface.

Communication Through a Large Reflecting Surface With Phase Errors

“…The ideal case of no phase errors and Rayleigh fading (i.e., a = √ π/2) is studied in [9], which Corollary 1 recovers.…”

“…where X is the transmitted symbol with mean zero and E[X 2 ] = 1, W ∼ CN (0, 1) models the normalized receiver noise and γ 0 is the average SNR when only one reflector is present and accounts for path loss, shadowing and reflection loss. Ideally, given the phases arg(H i1 ) and arg(H i2 ), the phase φ i is set so as to cancel the overall phase shift arg(H i1 ) + arg(H i2 ), which maximizes the SNR at the receiver [9]. Assuming the phase shifts induced by the channels are not estimated perfectly and/or the desired phases cannot be set precisely (e.g., when only a discrete set of phases is technologically possible), we model the deviation of φ i from the ideal setting by the phase noise Θ i , which is randomly distributed on [−π, π) according to a certain circular distribution [12].…”

“…The focus of this paper is on the concept of a large reflective surface (LRS) which, irrespective of the building technology, can be abstracted into an array of passive reflector elements that induce adjustable phase shifts on the reflected signals. An LRS placed somewhere between a source and a destination can greatly enhance the communication between the two when the phase shifts are appropriately configured such that the reflected waves combine coherently at the destination [1], [7], [8], [9]. Most of the studies assume the phase shifts induced by the composite propagation channel through the LRS are perfectly known and the reflector phases are set to the ideal values, with no errors.…”

A Single-RF Architecture for Multiuser Massive MIMO Via Reflecting Surfaces

“…Inspired by promising performance gains obtained via reflecting surfaces, several recent studies have proposed reflecting-surfaceassisted architectures for MIMO transmission. In [6], reflecting surfaces have been employed to improve signal transmission in a pointto-point communication scenario. This idea was further extended to multiuser scenarios in [7], where a symbol-level precoding scheme Emails: {ali.bereyhi, vahid.jamali, ralf.r.mueller, georg.fischer, robert.…”

“…is designed via intelligent reflecting surfaces for downlink transmission in multiuser MIMO settings. Some recent studies in this respect can be followed in [5][6][7][8][9][10] and the references therein.…”