Towards Context Information-based High-Performing Connectivity in Internet of Vehicle Communications
Doktorsavhandling, 2022

Internet-of-vehicles (IoV) is one of the most important use cases in the fifth generation (5G) of wireless networks and beyond. Here, IoV communications refer to two types of scenarios: serving the in-vehicle users with moving relays (MRs); and supporting vehicle-to-everything (V2X) communications for, e.g., connected vehicle functionalities. Both of them can be achieved by transceivers on top of vehicles with growing demand for quality of service (QoS), such as spectrum efficiency, peak data rate, and coverage probability. However, the performance of MRs and V2X is limited by challenges such as the inaccurate prediction/estimation of the channel state information (CSI), beamforming mismatch, and blockages. Knowing the environment and utilizing such context information to assist communication could alleviate these issues. This thesis investigates various context information-based performance enhancement schemes for IoV networks, with main contributions listed as follows.

In order to mitigate the channel aging issue, i.e., the CSI becomes inaccurate soon at high speeds, the first part of the thesis focuses on one way to increase the prediction horizon of CSI in MRs: predictor antennas (PAs). A PA system is designed as a system with two sets of antennas on the roof of a vehicle, where the PAs positioned at the front of the vehicle are used to predict the CSI observed by the receive antennas (RAs) that are aligned behind the PAs. In PA systems, however, the benefit is affected by a variety of factors. For example, 1) spatial mismatch between the point where the PA estimates the channel and the point where the RA reaches several time slots later, 2) antenna utilization efficiency of the PA, 3) temporal evolution, and 4) estimation error of the PA-base station (BS) channel.

First, in Paper A, we study the PA system in the presence of the spatial mismatch problem, and propose an analytical channel model which is used for rate adaptation. In paper B, we propose different approximation schemes for the analytical investigation of PA systems, and study the effect of different parameters on the network performance. Then, involving PAs into data transmission, Paper C and Paper D analyze the outage- and the delay-limited performance of PA systems using hybrid automatic repeat request (HARQ), respectively. As we show in the analytical and the simulation results in Papers C-D, the combination of PA and HARQ protocols makes it possible to improve spectral efficiency and adapt the transmission parameters to mitigate the effect of spatial mismatch. Finally, a review of PA studies in the literature, the challenges and potentials of PA as well as some to-be-solved issues are presented in Paper E.

The second part of the thesis focuses on using advanced technologies to further improve the MR/IoV performance. In Paper F, a cooperative PA scheme in IoV networks is proposed to mitigate both the channel aging effect and blockage sensitivity in millimeter-wave channels by collaborative vehicles and BS handover. Then, in Paper G, we study the potentials and challenges of dynamic blockage pre-avoidance in IoV networks.

temporal correlation


Internet-of-vehicles (IoV)

reconfigurable intelligent surface


wireless backhaul

outage probability

channel state information (CSI)


spatial correlation

rate adaptation

mobile relay


vehicle-to-everything (V2X)

Marcum Q-function

integrated access and backhaul (IAB)

predictor antenna


millimeter wave

Room EB
Opponent: Prof. Eduard Jorswieck, TU Braunschweig, Germany


Hao Guo

Chalmers, Elektroteknik, Kommunikation, Antenner och Optiska Nätverk

Rate Adaptation in Predictor Antenna Systems

IEEE Wireless Communications Letters,; Vol. 9(2020)p. 448-451

Artikel i vetenskaplig tidskrift

A Semi-Linear Approximation of the First-Order Marcum Q-function with Application to Predictor Antenna Systems

IEEE Open Journal of the Communications Society,; Vol. 2(2021)p. 273-286

Artikel i vetenskaplig tidskrift

Power Allocation in HARQ-based Predictor Antenna Systems

IEEE Wireless Communications Letters,; Vol. 9(2020)p. 2025-2029

Artikel i vetenskaplig tidskrift

On Delay-limited Average Rate of HARQ-based Predictor Antenna Systems

IEEE Wireless Communications Letters,; Vol. 10(2021)p. 1628-1632

Artikel i vetenskaplig tidskrift

Predictor Antenna: A Technique to Boost the Performance of Moving Relays

IEEE Communications Magazine,; Vol. 59(2021)p. 80-86

Artikel i vetenskaplig tidskrift

High-Rate Uninterrupted Internet of Vehicle Communications in Highways: Dynamic Blockage Avoidance and CSIT Acquisition

IEEE Communications Magazine,; Vol. 60(2022)p. 44-50

Artikel i vetenskaplig tidskrift

H. Guo, B. Makki, M. Åström, M.-S. Alouini, and T. Svensson, “Dynamic blockage pre-avoidance using reconfigurable intelligent surfaces,” submitted to IEEE Communications Magazine, Jan. 2022.

Moving Relay: Boosting the Performance of Vehicular Users

Imagine you are sitting in a high-speed train and using your mobile phone for checking messages or watching online streams. Although you already paid for 4G or even 5G services, the signal becomes weak now and then, especially when the train goes through caves and forests. You look out of the window, and the radio base station (BS) comes and goes. You can't stop but wonder: Can the data speed of my phone match the speed of the train?

Yes, of course! As one type of wireless communication service, internet-of-vehicles (IoV) communications becomes more and more important in our daily life. Serving in-vehicle users is one of the application scenarios in IoV networks. With the recent development of communication technologies, the radio signals become more and more robust in various IoV applications. However, there is still room for improvements especially when 1) the vehicle is moving quickly; 2) the environment changes fast; and 3) many users need to be served. Deploying moving relays (MRs) on the top of vehicles to enhance the signal propagation from the radio BS has great potential to mitigate these challenges.

This thesis focuses on how to improve the performance of MRs using the information from the environment. For example, what does the environment look like? Are there any big blockages between the MR and the BS? Can we ask another MR to help us with radio transmissions? In this work, we develop various communication schemes to establish efficient, low-latency, and highly reliable IoV radio links. Compared to benchmark methods, our setups provide order-of-magnitude performance gains with reasonable deployment costs. Our work has great potential to be (partly) involved in future communication standards and eventually, makes our life slightly better.


Informations- och kommunikationsteknik







Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 5081



Room EB


Opponent: Prof. Eduard Jorswieck, TU Braunschweig, Germany

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