147 research outputs found
SAI: safety application identifier algorithm at MAC layer for vehicular safety message dissemination over LTE VANET networks
Vehicular safety applications have much significance in preventing road accidents and fatalities. Among others, cellular networks have been under investigation for the procurement of these applications subject to stringent requirements for latency, transmission parameters, and successful delivery of messages. Earlier contributions have studied utilization of Long-Term Evolution (LTE) under single cell, Friis radio, or simplified higher layer. In this paper, we study the utilization of LTE under multicell and multipath fading environment and introduce the use of adaptive awareness range. Then, we propose an algorithm that uses the concept of quality of service (QoS) class identifiers (QCIs) along with dynamic adaptive awareness range. Furthermore, we investigate the impact of background traffic on the proposed algorithm. Finally, we utilize medium access control (MAC) layer elements in order to fulfill vehicular application requirements through extensive system-level simulations. The results show that, by using an awareness range of up to 250โm, the LTE system is capable of fulfilling the safety application requirements for up to 10 beacons/s with 150 vehicles in an area of 2 ร 2โkm2. The urban vehicular radio environment has a significant impact and decreases the probability for end-to-end delay to be โค100โms from 93%โ97% to 76%โ78% compared to the Friis radio environment. The proposed algorithm reduces the amount of vehicular application traffic from 21โMbps to 13โMbps, while improving the probability of end-to-end delay being โค100โms by 20%. Lastly, use of MAC layer control elements brings the processing of messages towards the edge of network increasing capacity of the system by about 50%
Design of an adaptive congestion control protocol for reliable vehicle safety communication
[no abstract
์ ๋ฃฐ๋ฌ ์ฌ์ด๋๋งํฌ ์ฑ๋ฅ ํฅ์์ ์ํ ์์๊ณ์ธต ๊ธฐ๋ฒ
ํ์๋
ผ๋ฌธ (๋ฐ์ฌ) -- ์์ธ๋ํ๊ต ๋ํ์ : ๊ณต๊ณผ๋ํ ์ ๊ธฐยท์ ๋ณด๊ณตํ๋ถ, 2020. 8. ๋ฐ์ธ์
.In typical cellular communications, User Equipments (UEs) have always had to go through a Base Station (BS) to communicate with each other, e.g., a UE transmits a packet to a BS via uplink and then the BS transmits the packet to another UE via downlink. Although the communication method can serve UEs efficiently, the communication method can cause latency problems and overload problems in BS. Thus, sidelink has been proposed to overcome these problems in 3GPP release 12. Through sidelink, UEs can communicate directly with each other.
There are two representative communications using sidelink, i.e., Device-to-Device (D2D) communication and Vehicle-to-Vehicle (V2V) communication. In this dissertation, we consider three strategies to enhance the performances of D2D and V2V communications:
(i) efficient feedback mechanism for D2D communications,
(ii) context-aware congestion control scheme for V2V communication,
and (iii) In-Device Coexistence (IDC)-aware LTE and NR sidelink resource allocation scheme.
Firstly, in the related standard, there is no feedback mechanism for D2D communication because D2D communications only support broadcast-type communications. A feedback mechanism is presented for D2D communications.
Through our proposed mechanism, UEs can use the feedback mechanism without the help of BS and UEs do not need additional signals to allocate feedback resources. We also propose a rate adaptation algorithm, which consider in-band emission problem, on top of the proposed feedback mechanism.
We find that our rate adaptation achieves higher and stable throughput compared with the legacy scheme that complies to the standard.
Secondly, we propose a context-aware congestion control scheme for LTE-V2V communication. Through LTE-V2V communication, UEs transmit Cooperative Awareness Message (CAM), which is a periodic message, and Decentralized Environmental Notification Message (DENM), which is a event-driven message and allows one-hop relay. The above two messages have different characteristics and generation rule. Thus, it is difficult and inefficient to apply the same congestion control scheme to two messages. We propose a congestion control schemes for each message. Through the proposed congestion control schemes, UEs decide whether to transmit according to their situation. Through simulation results, we show that our proposed schemes outperform comparison schemes as well as the legacy scheme.
Finally, we propose a NR sidelink resource allocation scheme based on multi-agent reinforcement learning, which awares a IDC problem between LTE and NR in Intelligent Transport System (ITS) band.
First, we model a realistic IDC interference based on spectrum emission mask specified at the standard. Then, we formulate the resource allocation as a multi-agent reinforcement learning with fingerprint method. Each UE achieves its local observation and rewards, and learns its policy to increase its rewards through updating Q-network. Through simulation results, we observe that the proposed resource allocation scheme further improves Packet Delivery Ratio (PDR) performances compared to the legacy scheme.์ ํ์ ์ธ ์
๋ฃฐ๋ฌ ํต์ ์์๋, ๋จ๋ง๋ค์ ์๋ก ํต์ ํ๊ธฐ ์ํด ํญ์ ๊ธฐ์ง๊ตญ์ ๊ฑฐ์ณ์ผ ํ๋ค. ์๋ฅผ ๋ค๋ฉด, ๋จ๋ง์ด uplink๋ฅผ ํตํด ๊ธฐ์ง๊ตญ์๊ฒ ํจํท์ ์ ์กํ ๋ค์ ๊ธฐ์ง๊ตญ์ downlink๋ฅผ ํตํด ํด๋น ํจํท์ ์ ์กํด์ค๋ค. ์ด๋ฌํ ํต์ ๋ฐฉ์์ ๋จ๋ง๋ค์๊ฒ ํจ์จ์ ์ผ๋ก ์๋น์ค๋ฅผ ์ ๊ณตํ ์ ์์ง๋ง, ์ํฉ์ ๋ฐ๋ผ์๋ ์ง์ฐ๋ฌธ์ ์ ๊ธฐ์ง๊ตญ์ ๊ณผ๋ถํ ๋ฌธ์ ๋ฅผ ์ผ๊ธฐํ ์ ์๋ค. ๋ฐ๋ผ์ 3GPP release12์์ ์ด๋ฌํ ๋ฌธ์ ์ ๋ค์ ๊ทน๋ณตํ๊ธฐ ์ํด sidelink๊ฐ ์ ์๋์๋ค. ๋๋ถ์ ๋จ๋ง๋ค์ sidelink๋ฅผ ํตํด์ ์๋ก ์ง์ ํต์ ์ ํ ์ ์๊ฒ ๋์๋ค.
Sidelink๋ฅผ ์ฌ์ฉํ๋ ๋ ๊ฐ์ง ๋ํ์ ์ธ ํต์ ์ D2D(Device-to-Device) ํต์ ๊ณผ V2V(Vehicle-to-Vehicle) ํต์ ์ด๋ค. ๋ณธ ๋
ผ๋ฌธ์์๋ D2D ์ V2V ํต์ ์ฑ๋ฅ์ ํฅ์์ํค๊ธฐ ์ํ ์ธ๊ฐ์ง ์ ๋ต์ ๊ณ ๋ คํ๋ค. (i) D2D ํต์ ์ ์ํ ํจ์จ์ ์ธ ํผ๋๋ฐฑ ๋ฉ์ปค๋์ฆ, (ii) V2V ํต์ ์ ์ํ ์ํฉ์ธ์๊ธฐ๋ฐ ํผ์ก์ ์ด ๊ธฐ๋ฒ, ๊ทธ๋ฆฌ๊ณ (iii) IDC(In-Device Coexistence) ์ธ์ง ๊ธฐ๋ฐ sidelink ์์ ํ ๋น ๋ฐฉ์.
์ฒซ์งธ, ๊ด๋ จ ํ์ค์๋ D2D ํต์ ์ด ๋ธ๋ก๋์บ์คํธ ์ ํ์ ํต์ ๋ง์ ์ง์ํ๊ธฐ ๋๋ฌธ์ D2D ํต์ ์ ๋ํ ํผ๋๋ฐฑ ๋ฉ์ปค๋์ฆ์ด ์๋ค. ์ฐ๋ฆฌ๋ ์ด๋ฌํ ํ๊ณ์ ์ ๊ทน๋ณตํ๊ณ ์ D2D ํต์ ์ ์ํ ํผ๋๋ฐฑ ๋ฉ์ปค๋์ฆ์ ์ ์ํ๋ค. ์ ์๋ ๋ฉ์ปค๋์ฆ์ ํตํด, ๋จ๋ง์ ๊ธฐ์ง๊ตญ์ ๋์์์ด ํผ๋๋ฐฑ ๋ฉ์ปค๋์ฆ์ ์ฌ์ฉํ ์ ์์ผ๋ฉฐ ํผ๋๋ฐฑ ์์์ ํ ๋นํ๊ธฐ ์ํ ์ถ๊ฐ ์ ํธ๋ฅผ ํ์๋ก ํ์ง ์๋๋ค. ์ฐ๋ฆฌ๋ ๋ํ ์ ์๋ ํผ๋๋ฐฑ ๋ฉ์ปค๋์ฆ์์์ ๋์ํ ์ ์๋ data rate ์กฐ์ ๊ธฐ๋ฒ์ ์ ์ํ์๋ค. ์ฐ๋ฆฌ๋ ์๋ฎฌ๋ ์ด์
๊ฒฐ๊ณผ๋ฅผ ํตํ์ฌ, ์ ์ํ data rate ์กฐ์ ๊ธฐ๋ฒ์ด ๊ธฐ์กด ๋ฐฉ์๋ณด๋ค ๋ ๋๊ณ ์์ ์ ์ธ ์์จ์ ์ ๊ณตํ๋ ๊ฒ์ ํ์ธํ์๋ค.
๋์งธ, LTE-V2V ํต์ ์ ์ํ ์ํฉ ์ธ์ง ๊ธฐ๋ฐ ํผ์ก ์ ์ด ๊ธฐ๋ฒ์ ์ ์ํ๋ค. LTE-V2V ํต์ ์์ ๋จ๋ง๋ค์ ์ฃผ๊ธฐ์ ์ธ ๋ฉ์์ง์ธ CAM(Cooperative Awareness Message) ๋ฐ ๋น์ฃผ๊ธฐ์ ๋ฉ์์ง์ด๋ฉฐ one-hop๋ฆด๋ ์ด๋ฅผ ํ์ฉํ๋ DENM(Decentralized Environmental Notification Message)๋ฅผ ์ ์กํ๋ค. ์์ ๋ ๋ฉ์์ง๋ ํน์ฑ๊ณผ ์์ฑ ๊ท์น์ด ๋ค๋ฅด๊ธฐ ๋๋ฌธ์ ๋์ผํ ํผ์ก ์ ์ด ๊ธฐ๋ฒ์ ์ ์ฉํ๋ ๊ฒ์ ๋นํจ์จ์ ์ด๋ค. ๋ฐ๋ผ์ ์ฐ๋ฆฌ๋ ๊ฐ ๋ฉ์์ง์ ์ ์ฉํ ์ ์๋ ํผ์ก ์ ์ด ๊ธฐ๋ฒ๋ค์ ์ ์ํ๋ค. ์ ์๋ ๊ธฐ๋ฒ๋ค์ ํตํด์ ๋จ๋ง๋ค์ ๊ทธ๋ค์ ์ํฉ์ ๋ฐ๋ผ์ ์ ์ก ์ฌ๋ถ๋ฅผ ๊ฒฐ์ ํ๊ฒ ๋๋ค. ์๋ฎฌ๋ ์ด์
๊ฒฐ๊ณผ๋ฅผ ํตํด ์ ์๋ ๊ธฐ๋ฒ์ด ๊ธฐ์กด ํ์ค ๋ฐฉ์ ๋ฟ๋ง ์๋๋ผ ์ต์ ์ ๋น๊ต ๊ธฐ๋ฒ๋ค๋ณด๋ค ์ฐ์ํ ์ฑ๋ฅ์ ์ป๋ ๊ฒ์ ํ์ธํ์๋ค.
๋ง์ง๋ง์ผ๋ก ITS(Intelligent Transport System)๋์ญ์์ LTE์ NR์ฌ์ด์ IDC๋ฌธ์ ๋ฅผ ๊ณ ๋ คํ๋ NR sidelink ์์ํ ๋น ๊ธฐ๋ฒ์ ์ ์ํ๋ค. ๋จผ์ , ํ์ค์ ์ง์ ๋ ์คํํธ๋ผ ๋ฐฉ์ถ ๋ง์คํฌ๋ฅผ ๊ธฐ๋ฐ์ผ๋ก ํ์ค์ ์ธ IDC ๊ฐ์ญ์ ๋ชจ๋ธ๋งํ๋ค. ๊ทธ๋ฐ ๋ค์ ๋ค์ค ์์ด์ ํธ ๊ฐํํ์ต์ผ๋ก ์์ํ ๋น ๊ธฐ๋ฒ์ ์ ์ํ๋ค. ๊ฐ ๋จ๋ง๋ค์ ์์ ๋ค์ ์ฃผ๋ณ ํ๊ฒฝ์ ๊ด์ธกํ๊ณ ๊ด์ธก๋ ํ๊ฒฝ์ ๊ธฐ๋ฐ์ผ๋ก ํ๋ํ์ฌ ๋ณด์์ ์ป๊ณ Q-network์ ์์ ์ ๋ณด์์ ์ฆ๊ฐ์ํค๋๋ก ์ ์ฑ
์ ์
๋ฐ์ดํธ ๋ฐ ํ์ตํ๋ค. ์ฐ๋ฆฌ๋ ์๋ฎฌ๋ ์ด์
๊ฒฐ๊ณผ๋ฅผ ํตํ์ฌ ์ ์๋ ์์ํ ๋น ๋ฐ์์ด ๊ธฐ์กด๊ธฐ๋ฒ ๋๋นํ์ฌ PDR(Packet Delivery Ratio) ์ฑ๋ฅ์ ํฅ์์ํค๋ ๊ฒ์ ํ์ธํ์๋ค.Introduction 1
Efficient feedback mechanism for LTE-D2D Communication 8
CoCo: Context-aware congestion control scheme for C-V2X communications 35
IDC-aware resource allocation based on multi-agents reinforcement learning 67
Concluding remarks 84
Abstract(In Korean) 96
๊ฐ์ฌ์ ๊ธ 99Docto
Safety on the roads: LTE alternatives for sending ITS messages
ยฉ ยฉ 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This article discusses different alternatives for sending intelligent transportation systems (ITS) messages using long-term evolution (LTE) networks. Specifically, it compares the unicast and evolved
Multimedia Broadcast Multicast Services (eMBMS) transmission modes by means of system-level simulations and a cost modeling analysis. The optimum configuration of the eMBMS carrier is studied for the case of ITS services. This article also includes some recommendations on the configuration of the ITS server in charge of distributing safety messages as well as on its interaction with the mobile network operator (MNO). The results show that eMBMS is significantly more efficient in terms of resource consumption than the unicast mode, implying an important reduction of the delivery costs.Calabuig Gaspar, J.; Monserrat Del Rรญo, JF.; Gozรกlvez, D.; Klemp, O. (2014). Safety on the roads: LTE alternatives for sending ITS messages. IEEE Vehicular Technology Magazine. 9(4):61-70. doi:10.1109/MVT.2014.2362272S61709
Open Platforms for Connected Vehicles
L'abstract รจ presente nell'allegato / the abstract is in the attachmen
Agile Data Offloading over Novel Fog Computing Infrastructure for CAVs
Future Connected and Automated Vehicles (CAVs) will be supervised by
cloud-based systems overseeing the overall security and orchestrating traffic
flows. Such systems rely on data collected from CAVs across the whole city
operational area. This paper develops a Fog Computing-based infrastructure for
future Intelligent Transportation Systems (ITSs) enabling an agile and reliable
off-load of CAV data. Since CAVs are expected to generate large quantities of
data, it is not feasible to assume data off-loading to be completed while a CAV
is in the proximity of a single Road-Side Unit (RSU). CAVs are expected to be
in the range of an RSU only for a limited amount of time, necessitating data
reconciliation across different RSUs, if traditional approaches to data
off-load were to be used. To this end, this paper proposes an agile Fog
Computing infrastructure, which interconnects all the RSUs so that the data
reconciliation is solved efficiently as a by-product of deploying the Random
Linear Network Coding (RLNC) technique. Our numerical results confirm the
feasibility of our solution and show its effectiveness when operated in a
large-scale urban testbed.Comment: To appear in IEEE VTC-Spring 201
On the Design of Sidelink for Cellular V2X: A Literature Review and Outlook for Future
Connected and fully automated vehicles are expected to revolutionize our mobility in the near future on a global scale, by significantly improving road safety, traffic efficiency, and traveling experience. Enhanced vehicular applications, such as cooperative sensing and maneuvering or vehicle platooning, heavily rely on direct connectivity among vehicles, which is enabled by sidelink communications. In order to set the ground for the core contribution of this paper, we first analyze the main streams of the cellular-vehicle-to-everything (C-V2X) technology evolution within the Third Generation Partnership Project (3GPP), with focus on the sidelink air interface. Then, we provide a comprehensive survey of the related literature, which is classified and critically dissected, considering both the Long-Term Evolution-based solutions and the 5G New Radio-based latest advancements that promise substantial improvements in terms of latency and reliability. The wide literature review is used as a basis to finally identify further challenges and perspectives, which may shape the C-V2X sidelink developments in the next-generation vehicles beyond 5G
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