Eﬃcient User Scheduling for Uplink Hybrid Satellite-Terrestrial Communication

2025-08-25 0 0 1.47MB 30 页 10玖币

侵权投诉

arXiv:2210.12920v1 [cs.IT] 24 Oct 2022

Eﬃcient User Scheduling for Uplink Hybrid

Satellite-Terrestrial Communication

Lina Zhu, Lin Bai, Lin Zhou and Jinho Choi

Abstract

Due to increasing demands of seamless connection and massive information exchange across the

world, the integrated satellite-terrestrial communication systems develop rapidly. To shed lights on the

design of this system, we consider an uplink communication model consisting of a single satellite, a

single terrestrial station and multiple ground users. The terrestrial station uses decode-and-forward (DF)

to facilitate the communication between ground users and the satellite. The channel between the satellite

and the terrestrial station is assumed to be a quasi-static shadowed Rician fading channel, while the

channels between the terrestrial station and ground users are assumed to experience independent quasi-

static Rayleigh fading. We consider two cases of channel state information (CSI) availability. When

instantaneous CSI is available, we derive the instantaneous achievable sum rate of all ground users and

formulate an optimization problem to maximize the sum rate. When only channel distribution information

(CDI) is available, we derive a closed-form expression for the outage probability and formulate another

optimization problem to minimize the outage probability. Both optimization problems correspond to

scheduling algorithms for ground users. For both cases, we propose low-complexity user scheduling

algorithms and demonstrate the eﬃciency of our scheduling algorithms via numerical simulations.

Index Terms

Hybrid satellite-terrestrial communication systems, decode-and-forward, user scheduling, outage

probability, space-air-ground integrated networks

L. Zhu is with the School of Communication Engineering, Hangzhou Dianzi University, Hangzhou, Zhejiang, China, 310018

(Email: zhulina@hdu.edu.cn). She was with the School of Electronic and Information Engineering, Beihang University, Beijing,

China, 100083 (Email: zhulina@buaa.edu.cn)

L. Bai and L. Zhou are with the School of Cyber Science and Technology, Beihang University, Beijing, China, 100083 (Emails:

{l.bai, lzhou}@buaa.edu.cn). They are also with the Beijing Laboratory for General Aviation Technology, Beihang University,

Beijing.

J. Choi is with the School of Information Technology, Burwood, Deakin University, Australia (E-mail:

jinho.choi@deakin.edu.au).

I. Introduction

To expand communication to a broader coverage area and meet the demand of higher through-

put [1], [2], satellite communication systems have been extensively studied and utilized across

the world. Due to heavy shadowing caused by obstacles when the user moving into buildings or

vegetation areas, the line-of-sight (LOS) link between the satellite and terrestrial users might be

unavailable [3]. To combat the performance degradation, hybrid satellite-terrestrial relay systems

are proposed to improve coverage and reliability of satellite communication with the aid of

terrestrial relays [4]–[6]. Most current hybrid satellite-terrestrial systems adopt either amplify-

and forward (AF) or decode-and-forward (DF) [7], [8] relaying technique.

For a hybrid satellite-terrestrial system, the performance is strongly related to the design of

multiuser access schemes [8], relay selection methods [9] and power allocation strategies [10].

For satellite-terrestrial systems with a single relay, multiuser access schemes, especially user

scheduling algorithms, are critical and should be optimized jointly with power allocation schemes.

Furthermore, the development of integrated space-terrestrial information network (SIN) and the

6th Generation (6G) communication architecture enforces the system to allow access of massive

number of devices. To meet the extremely high throughout and massive connectivity demands

of future communication systems, it is vital to comprehensively study eﬃcient user scheduling

strategies with low complexity for hybrid satellite-terrestrial communication systems.

To shed lights on the design of such a system, we study user scheduling algorithms for the

hybrid satellite-terrestrial model with a single satellite, a single terrestrial station and multiple

ground users. The channel from the terrestrial station to the satellite is assumed to be a quasi-

static shadowed Rician fading channel, and the channel from each user to the terrestrial station

is assumed to be a quasi-static Rayleigh fading channel. Our choice of quasi-static fading is

validated by information theoretical analysis of low-latency communication in [11], [12]. In

particular, under quasi-static fading channels, the asymptotic notion of outage capacity and outage

probability provide tight approximations to the non-asymptotic performance at low latency. We

choose shadowed Rician fading since it provides a good approximation for the land-mobile

satellite communication channel [13]. For the links between each ground user and the relay, we

choose Rayleigh fading because it is widely used in wireless communications, and is accurate

for most terrestrial environment with rich scatters [14].

A. Main Contributions

We study the hybrid satellite-terrestrial model with either instantaneous channel state infor-

mation (CSI) or channel distribution information (CDI) available at the terrestrial station and

the satellite. When instantaneous CSI is available, the terrestrial station is informed of the exact

channel fading levels of each user, and the satellite is informed of the exact fading level from

the terrestrial station. When CDI is available, the terrestrial and the satellite are only provided

with the distribution of respective fading models. We study user scheduling algorithms for both

cases. Our contributions are summarized as follows.

When instantaneous CSI is available, combining capacity results for the multiple access

channel and the relay channel [15], we derive the optimal instantaneous achievable rate region

of all ground users. Subsequently, under a homogeneous target rate constraint, we formulate an

optimization problem to maximize the achievable sum rate via user scheduling algorithms. The

optimal solution requires an exhaustive search and is too complicated for practical use. As a

compromise, we ﬁrst derive theoretical upper and lower bounds on the maximum achievable

rate and then propose low-complexity scheduling algorithms. In particular, we propose a greedy

algorithm that achieves close-to-optimal performance and a further simpliﬁed sub-optimal algo-

rithm that has almost linear complexity. The eﬃciency, computational complexity and stability

of our scheduling algorithms are analytically demonstrated and numerically veriﬁed.

When CDI is available, the instantaneous achievable rate region can not be obtained. Instead,

under a homogeneous target rate constraint for all ground users, we derive the outage probability

of the uplink communication as a function of the rate constraint and CDI. Subsequently, we

formulate an optimization problem to minimize the outage probability and derive a theoretical

lower bound that serves as the benchmark. Furthermore, to obtain a feasible solution to the

optimization problem, we propose a user scheduling algorithm using the idea of alternative

optimization (AO) [16], [17]. Via numerical simulations, we ﬁnd that the outage probability

obtained from our user scheduling algorithm converges to our derived benchmark after a small

number of iterations. We also numerically illustrate the optimality and computational complexity

of our scheduling algorithm by comparing with the optimal exhaustive search method.

B. Related works

The study on hybrid satellite-terrestrial communication systems has a long history. In contrast

to our setting, most papers focused on the downlink model, where a satellite transmits messages

to a group of ground users, e.g., [18]–[22]. In [18], for a multiuser hybrid AF satellite-terrestrial

cooperative network, Yuan et al. proposed an opportunistic user scheduling algorithm using

signal-to-noise ratio (SNR)-threshold based feedback. In [19], for a multiuser AF hybrid satellite-

terrestrial relay network with opportunistic scheduling, Kang et al. derived the analytical bounds

on the ergodic capacity. For a multiuser satellite-terrestrial downlink model with a multi-antenna

satellite and a single-antenna AF relay, Bankey and Upadhyay [20] analyzed the ergodic capacity

for opportunistic user scheduling with outdated CSI. However, the spectrum eﬃciency of the

orthogonal opportunistic user scheduling algorithms of the above studies is very low since only

one user is allowed to access the channel at a time slot. To improve the throughput and spectrum

eﬃciency of the downlink hybrid system, subsequent works apply non-orthogonal multiple access

(NOMA) into hybrid satellite-terrestrial systems to support multiple users simultaneously in a

time slot, e.g., [21], [22]. However, studies on downlink NOMA-based integrated terrestrial-

satellite network are signiﬁcantly diﬀerent from our uplink analysis in this paper.

The more related works to ours is the studies of the uplink hybrid satellite-terrestrial system,

e.g., [23]–[25]. In [23], Yang et al. derived an upper bound on the ergodic capacity for a multi-

beam geostationary earth orbit mobile satellite communication system. In [24], Huang et al.

proposed a space division multiple access (SDMA) scheme to maximize the average sum rate

of a hybrid satellite-terrestrial AF relaying network, where a high-altitude platform is deployed

as a relay to assist the transmission from ground users to the satellite. In [25], Arti studied a

two-way AF satellite system with only two ground users and one terrestrial relay and designed

beamforming and combining vectors for the satellite.

However, none of the above works use Shannon theory [26] to study the critical problem of

eﬃcient user scheduling algorithms to achieve the full potential of the uplink hybrid satellite-

terrestrial system. Although above works considered multiple antennas, the analysis is mostly

achievable without optimality guarantee. Speciﬁcally, these studies used dimensional advantage

of multiple antennas to improve the throughout with SDMA or a certain beamforming design.

Note that the capacity is the maximal rate achievable of any communication scheme and analysis

based on speciﬁc coding scheme without optimality guarantee is far from satisfactory. In this

paper, to complement the existing literature in the uplink hybrid satellite-terrestrial system, we

use information theoretical results to study eﬃcient user scheduling algorithms and demonstrate

close-to-optimality performance of our proposed algorithms. For simplicity, we present results

for the single antenna terminals in this paper. Our results can be generalized to the multi

[ ] {1,2, , }N N }

{ | [ ], 1,2, , }

k k

u u N k K  }u

Selected user group

Total user group

D,R

Fig. 1. System model of the hybrid satellite-terrestrial communication network.

antenna terminals by using corresponding information theoretical results for the multiple input

and multiple out channels [27], [28].

II. Problem Formulation

Notation

We use R,R+and Nto denote the set of real numbers, positive numbers and integers

respectively. Denote by A \ B the minus between set Aand B. For any x∈R, we use ⌊x⌋

to denote the maximum integer that is less than or equal to x. For any (a,b)∈N2, we use [a:b]

to denote the set of integers between aand band use [a] to denote [1 : a]. Furthermore, for any

two integers (a,b)∈N2such that a<b, denote by [b]athe set of vectors that contain exactly a

unique elements of [b] and by F(a,b) the set of bijective mappings from [b]ato [b]a.

A. The Uplink Communication Model

We consider an uplink model for the hybrid satellite-terrestrial communication system as shown

in Fig. 1. There are Nground users with indices N=[N], one terrestrial relay, and one satellite,

文档加载中……请稍候！
如果长时间未打开，您也可以点击刷新试试。

下载文档到电脑，查找使用更方便

10 玖币 0人已下载

立即下载

摘要：

arXiv:2210.12920v1[cs.IT]24Oct20221EﬃcientUserSchedulingforUplinkHybridSatellite-TerrestrialCommunicationLinaZhu,LinBai,LinZhouandJinhoChoiAbstractDuetoincreasingdemandsofseamlessconnectionandmassiveinformationexchangeacrosstheworld,theintegratedsatellite-terrestrialcommunicationsystemsdeveloprapidl...

展开>> 收起<<

Eﬃcient User Scheduling for Uplink Hybrid Satellite-Terrestrial Communication.pdf

共30页,预览5页

还剩页未读，继续阅读

声明：本站为文档C2C交易模式，即用户上传的文档直接被用户下载，本站只是中间服务平台，本站所有文档下载所得的收益归上传人(含作者)所有。玖贝云文库仅提供信息存储空间，仅对用户上传内容的表现方式做保护处理，对上载内容本身不做任何修改或编辑。若文档所含内容侵犯了您的版权或隐私，请立即通知玖贝云文库，我们立即给予删除！

Eﬃcient User Scheduling for Uplink Hybrid Satellite-Terrestrial Communication

相关推荐

开通VIP享超值会员特权

作者详情

相关内容

热门标签

举报选择: