🏛️國立陽明交通大學機構典藏

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3GPP NR Sidelink Transmissions Toward 5G V2X
(2020-01-01)
Lien, Shao-Yu
;
Deng, Der-Jiunn
;
Lin, Chun-Cheng
;
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.
A Dynamic Hybrid Counting Procedure for eMBMS of 3GPP
(2017-01-01)
Huang, Yuehong
;
Tseng, Yu-Chee
;
資訊工程學系
;
Department of Computer Science
In this paper, we identify two inefficiencies in the counting procedure of the evolved Multimedia Broadcast Multicast Service (eMBMS) in 3GPP: (1) it may consume too much network resources in determining the number of User Equipments (UEs) which are interested in receiving MBMS services, and (2) it is too conservative in that the counting results may be smaller than actual numbers because those UEs in the RRC_IDLE state are ignored (for avoiding RACH congestion). We then propose a new dynamic method by combining the theory of Geometric Splitting-based Estimation (GSE) and the theory of probability to accelerate the eMBMS counting procedure. Compared to the original eMBMS counting procedure, which only counts the UEs in the RRC_CONNECTED state, our scheme also counts the UEs in the RRC_IDLE state. However, our method still improves the accuracy of counting results and saves radio resources.
Data Offloading for Dynamic Point Selection in Cloud Radio Access Networks (C-RAN)
(2018-01-01)
Hsu, Ching-Kuo
;
Liang, Jia-Ming
;
Chen, Jen-Jee
;
Wu, Kun-Ru
;
Tseng, Yu-Chee
For next generation mobile communications. Cloud-RAN (C-RAN) is an emerging network architecture to provide broadband services. C-RAN separates computation entities, i.e., Baseband Units (BBUs), from base stations (BSs) and puts BBUs in a cloud located in a centralized network. With C-RAN, UEs can receive data from multiple collaborative cells and thus can leverage the dynamic point selection (DPS) technology to improve network efficiency. When user equipments (UEs) enter a hotspot and can not be served due to congestion, data offloading from the hotspot to its neighboring cells may take place to balance heterogeneous cells' loads. This work shows how to integrate such DPS offloading with the Discontinuous Reception (DRX) mechanism, which allows UEs to turn off their radio interfaces in a periodical manner. We address the resource allocation problem in heterogeneously-loaded C-RAN by optimizing UEs' energy consumption based on DRX while reserving sufficient bandwidths for UEs considering their quality-of-service (QoS) through DPS. We propose an offloading-based DPS scheduling scheme by exploiting not only maximal instantaneous throughputs but also minimal energy cost. Simulation results show that our scheme can improve throughput, resource utilization, and energy consumption as compared to existing schemes.
A Dynamic Reservation Scheme in Online Charging System for Family Shared Plan
(2015)
Huang, Huai-Sheng
;
Su, Tzu-Chung
;
Liang, Jia-Ming
;
Tseng, Yu-Chee
;
資訊工程學系
For simplifying billing and limiting data usage, Family Shared Plan (FSP) is now a popular plan provided by telecommunications operators. Based on the 3rd Generation Partnership Project (3GPP) specifications, Online Charging System (OCS) has to determine the Granted Unit (GU) and create reservations per session before a service is delivered by the serving network to a User Equipment (UE). However, fixed GUs cannot adapt to dynamic consumer behaviors, which usually require dynamic GUs. Clearly, giving small GUs will incur too many signaling messages for making reservations, but giving excessive GUs will cause unbalanced distribution of resources, especially in FSP cases. How to determine GUs is an open issue that can be self-defined by telecommunications operators. In this paper, we propose a new scheme for dynamically assigning GUs to UEs belonging to the same FSP, based on their historical data usage and total monthly data allowance. Simulation results show that our scheme can substantially save signalings by at least 22% compared to fixed scheme under unpredictable behaviors.

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🏛️國立陽明交通大學機構典藏

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