Making Two-Way Satellite Relaying Feasible: A Differential Modulation Based Approach

Abstract

In this paper, we study two-way satellite relaying between two earth stations (ESs) willing to exchange their signals via a satellite. The satellite communication has big problems of propagation delay and fast channel gain fluctuations, due to which it is difficult to generate perfect channel information in ESs for self interference cancellation and decoding of transmitted symbols. Therefore, the usual two-way relaying developed for the terrestrial links is not applicable for the satellite links. In order to avoid the problem of channel estimation, we propose to use differential modulation in both ESs. Then we develop a differential detector of the symbols transmitted by the ESs. The satellite is assumed to be of transparent type. The proposed differential decoder allows for self interference cancellation and detection of the transmitted symbols without any channel information. However, the proposed differential detector requires a relative rotation between the constellations of both ESs for performing satisfactorily. The proposed two-way relaying is useful for the satellite communication systems as it allows the ESs to exchange their data via satellite without any training. The pairwise error probability (PEP) of the proposed scheme is also derived. Based on the PEP, we analytically find the diversity of the considered system. Index Terms-Amplify-and-forward (AF) protocol, differential modulation, land mobile satellite (LMS) links, M-ary phase shift keying (M-PSK), satellite communications, Shadowed-Rician (SR) distribution, two-way relaying.

Performance Analysis for Training-Based Multipair Two-Way Full-Duplex Relaying With Massive Antennas

“…Thus we can obtain the power constraint factor α by substituting (20) and (21) into (4). In the following theorem, we derive an approximate closedform expression of the achievable lower bound given by (17).…”

“…We set P R = ηP S based on Corollary 4. The "Statistical CSI: lower bound" curve is generated from (17), where the statistical distributions 10 Note that Tc is inversely proportional to the Doppler spread, thus its value is large for cases of low mobility (for example, the relay is fixed geographically) and small for cases of high mobility (for example, a mobile terminal serves as the relay), and we set Tc = 100 for cases of low mobility. Besides, both cases of high and low mobilities are considered in Fig.…”

“…For example, the authors in [16] studied the performance of a two-way amplifyand-forward (AF) MIMO relay system based on orthogonal space-time block codes (OSTBCs). In [17], a differential modulation based two-way relaying protocol was proposed for two-way AF satellite relaying communication. In [18], the joint beamforming optimization and power control were investigated for a two-way FD MIMO relay system.…”

Channel Estimation and Detection in Hybrid Satellite–Terrestrial Communication Systems

“…Another important difference is that satellite link is very fast fading than the terrestrial link. The issue of latency and fast variation of satellite links from channel estimation point of view are thoroughly discussed in [17]. For hybrid communication system, since the nature of both links are different, following problems arise: 1) The separate estimation of satellite link at the relay ES leads to significant feed-forward overhead as the channel estimates have to be reported to the destination ES without any error.…”

On the secrecy performance of integrated satellite‐aerial‐terrestrial networks

“…However, the obstacles, shadowing and masking between satellite and terrestrial terminals, often seriously affect the quality of the line‐of‐sight (LoS) communications and deteriorate the wireless transmission reliability. To improve the performance of SatCom under these adverse conditions, the relay technology has been widely used . On the other hand, the terrestrial fixed relay is limited with the deployment inefficiency and inflexibility in remote area and emergency environment and to users with important communication missions .…”