在5G車隊通訊中，車隊領導(PL)使用群組傳播，旨在提供有效且可靠的通訊，傳送控制訊息給車隊中的車隊成員(PM)。由於群組傳播的範圍有限，車隊可能需要選擇一輛PM車輛作為車隊中繼(PR)車輛將PL的訊息轉發給在PL群組傳播範圍外的PM車輛。除了群組傳播，PM車輛還需要傳輸單點傳播控制訊息給其後方跟隨的PM車輛以做到緊急控制來避免事故。由於頻譜資源有限，通常採用資源共享來提高頻譜效率。本篇論文針對群組傳播和單點傳播提出了基於傳輸可靠性的資源分配方法。 本篇論文的主要資源共享原則如下：（一）一個PL車輛或一個PR車輛不能跟任何PM車輛共享子通道，但可以跟一個獨自個體的上傳子通道共享，獨自個體可以是一個手機使用者或未加入任何車隊的自由車輛；（二）被PM車輛使用的子通道可以被同車隊的PM車輛和/或不同車隊的PM車輛在一些限制下重複使用；（三）獨自個體間不共享頻譜。對於群組傳播，本篇論文提出了“三方配對車隊群組傳播(TMPG) ”方法，使用三方配對來將（一）一個分配的子通道、（二）一個PL車輛或一個PR車輛、（三）一個獨自個體配對在一起。對於單點傳播，本篇論文提出“資源共享單點傳播(RSPU)方法”，首先考慮同群集干擾將PM車輛分群，然後使用三方配對來將（一）一個分配的子通道、（二）一個PM車輛的群集、（三）一個獨自個體配對在一起。 此外，RSPU方法調整群集數以最小化分配給車隊的資源。模擬結果顯示，提出的方法在QoS滿足率、車隊分配的子通道數、頻譜效率方面比其他方法有更好的表現。

In 5G platoon communications, the Platoon Leader (PL) uses groupcasting, which aims to provide efficient and reliable communication, to transmit control messages to all Platoon Member (PM) vehicles in the platoon. Since the groupcasting range is limited, a platoon may need to pick one PM vehicle as the Platoon Relay (PR) vehicle to forward PL’s messages to PM vehicles outside PL’s groupcasting range. In addition to groupcasting, a PM vehicle also needs to transmit unicast control messages to its follow-up PM vehicles for emergent control to avoid accident. Since the spectrum resource is limited, resource sharing is normally adopted to improve spectrum efficiency. This work proposes the resource allocation methods for both groupcasting and unicasting based on transmission reliability. The main resource sharing’s principle of this work is as follows: (i) a PL vehicle or a PR vehicle cannot share its subchannel with any PM vehicle but can share its subchannel with one individual entity’s uplinked subchannel, which can be a cellular phone user or a free vehicle that does not join any platoon; (ii) the subchannel used by a PM vehicle can be reused by other intra-platoon PM vehicles and/or inter-platoon PM vehicles under some constraints; (iii) no subchannel sharing among individual entities. For groupcasting, this work proposed the Tripartite Matching for Platoon Groupcasting (TMPG) method using tripartite matching to match (i) an allocated subchannel, (ii) a PL vehicle or a PR vehicle and (iii) an individual entity together. For unicasting, this work proposed the Resource Sharing for Platoons’ Unicasting (RSPU) method that firstly partitions PM vehicles into clusters considering the intra-cluster interference, and then uses tripartite matching to match (i) an allocate subchannel, (ii) a cluster of PM vehicles and (iii) an individual entity together. Additionally, the RSPU method adjusts the number of clusters to minimize the allocated subchannel to platoons. The simulation results shown that the proposed methods can have the better performance in terms of QoS’s satisfaction rate, number of allocated subchannels for platoons and spectral efficiency comparing with the other methods.

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