Browsing by Author "Lien, Shao-Yu"

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3GPP NR Sidelink Transmissions Toward 5G V2X
(2020-01-01)
Lien, Shao-Yu
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Deng, Der-Jiunn
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Lin, Chun-Cheng
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Tsai, Hua-Lung
;
Chen, Tao
Featuring direct communications between two user equipments (UEs) without signal relay through a base station, 3GPP sidelink transmissions have manifested their crucial roles in the Long-Term Evolution (LTE) Advanced (LTE-A) for public safety and vehicle-to-everything (V2X) services. With this successful development in LTE-A, the evolution of sidelink transmissions continues in 3GPP New Radio (NR), which renders sidelink an inevitable component as well as downlink and uplink. Targeting at offering low latency, high reliability and high throughout V2X services for advanced driving use cases, a number of new sidelink functions not provided in the LTE-A are supported in NR, including the feedback channel, grant-free access, enhanced channel sensing procedure, and new control channel design. To fully comprehend these new functions, this paper therefore provides essential knowledge of 3GPP NR sidelink transmissions, including the physical layer structure, resource allocation mechanisms, resource sensing and selection procedures, synchronization, and quality-of-service (QoS) management. Furthermore, this paper also provides performance evaluation to assess the gains brought from the new control channel design. As NR sidelink transmissions have been regarded as a foundation to provide advanced services other than V2X in future releases (e.g., advanced relay), potential enhancements are also discussed to serve the urgent demand in corresponding normative works.
IEEE 802.11ba Wake-Up Radio: Performance Evaluation and Practical Designs
(2020-01-01)
Deng, Der-Jiunn
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Lien, Shao-Yu
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Lin, Chun-Cheng
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Gan, Ming
;
Chen, Hsing-Chung
Featuring a long operation time to avoid frequent battery replacements, highly energy-efficient radios have shown their pivotal functions for low-power and battery-driven devices in supporting manifold Internet-of-Things (IoT) services. To this end, prolific systems for highly energy-efficient radios have been widely deployed, but they impose a critical challenge of sacrificed data rates to preclude the applications that both require high energy efficiency and high data rates. Recently, this challenge has driven the concept of equipping two radio-chains on a low-power device, known as the primary connectivity radio (PCR) and companion connectivity radio (CCR). The PCR supports high data rate transmissions, and switches to the sleeping mode when no data should be received. In this case, the CCR stays awake to monitor traffic, and wakes up the PCR when data requiring to be received arrives. However, to practice such a concept, sophisticated operations in the physical (PHY) layer and medium access control (MAC) layers are required. Consequently, the IEEE 802.11 Task Group "ba" (TGba) has been formed to launch the normative works since 2017. In the normative development, the most challenging issue lies in the design of a new frame structure especially the preamble sequence, by which the CCR in a station (STA) can efficiently synchronize with an access point (AP) and the PCR can be promptly waken up when an AP wishes to transmit data to an STA. To comprehend such a crucial foundation for the next generation low-power IoT devices, this paper provides comprehensive knowledge of state-of-the-art PHY/MAC operations of IEEE 802.11ba. Most importantly, a preamble sequence design for synchronization is further proposed for the new frames supported in IEEE 802.11ba. Through comprehensively evaluating the performance of different designs (in terms of data rate configuration and synchronization sequences), we justify the outstanding performance of the proposed design in terms of the synchronization error rate and packet error rate, to satisfy the urgent demands in the normative works of IEEE 802.11ba.
Latency Control in Software-Defined Mobile-Edge Vehicular Networking
(2017-08-01)
Deng, Der-Jiunn
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Lien, Shao-Yu
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Lin, Chun-Cheng
;
Hung, Shao-Chou
;
Chen, Wei-Bo
A cloud radio access network deployed on top of edge networks as a software-defined radio access network architecture has been regarded as a promising paradigm for the next generation mobile networks, but it has not received considerable attention in the vehicular industry due to distinct design needs. For mobile networks, infrastructures provide powerful computation capability for universal radio resource optimization, and therefore an inherent "cloud-down" design is favorable. On the contrary, to deploy vehicular technologies, sophisticated processing capability has been a baseline feature for the next generation driving machines, which may not solely rely on wireless infrastructures to guarantee driving safety, so an "edge-up" design is preferred. Consequently, this article surveys the recent works on software-defined vehicular networks and proposes a series of edge-up software-defined networking designs, particularly emphasizing the most crucial function of latency control to support possible wireless applications for the next generation driving machines. The proposed designs thus create a paradigm shift to enable software-defined mobile-edge vehicular networking.