本論文提出了基於目前無線電接入網(RAN)的阻塞來動態分配eMBMS的無線資源，並基於給定的eMBMS無線資源選擇一些多媒體串流服務並將其轉換為eMBMS session以緩解目前的RAN的阻塞。由於在不適當的時間使用eMBMS可能會導致無線資源的浪費，並且eMBMS session的串流品質和編碼率無法根據每個涉及eMBMS的UE的狀態來即時地動態調整，因此系統應盡可能地使用單播來傳輸數據，以保持eNB對於UE調度/無線資源分配的靈活性。因此，本論文將在保持eNB對於UE調度/無線資源分配的靈活性與最小化UE的封包無效率間做出折衷。此外，由於可用於多播/廣播方式支持多媒體串流服務的eMBMS無線資源是有限，因此為了發揮eMBMS的最大利益，必須選擇一些合適的多媒體流服務切換到eMBMS來進行傳輸，並讓其餘的多媒體串流服務繼續使用單播通信來傳輸。為了使eMBMS能有效地緩解RAN阻塞，本論文提出的方法包含 (i) 基於RAN阻塞狀況來動態增加/減少eMBMS的無線資源量， (ii) 利用背包演算法根據給定的eMBMS無線資源量來選擇適合轉為eMBMS session的多媒體串流服務以最小化UE的封包無效率及最大化UE的位元率，並 (iii) 根據各eMBMS session的傳輸需求來設計一個低冗餘資源占用的CSA Pattern。根據實驗結果，提出的方法能在不斷變動的網路環境中為UE提供更為穩定的無線資源量並有效的降低整體UE的平均封包遺失率，特別是在高密度的環境中。

The technique of evolved Multimedia Broadcast Multicast Service (eMBMS) using the Multicast Broadcast Single Frequency Network (MBSFN) technique was designed for having multimedia streaming services using the multicast and broadcast way over the 4G/5G cellular network. Since (i) the unit of resource allocation in eMBMS-MBSFN is a subframe, which is a resource block (RB) for unicast communication, (ii) the code rate of an eMBMS-MBSFN session is based on the lowest Modulation and Coding Scheme (MCS) among involved User Equipments (UEs) of the eMBMS session and (iii) the resource allocation for eMBMS-MBSFN cannot be so instantly and dynamically adjusted based on the status of involved UEs, triggering eMBMS in the inappropriate time and allocating inappropriate resource to eMBMS may cause (1) the radio resources to be wasted and (2) the low streaming quality and code rate. Based on the MBMS operation on Demand (MooD) concept, this work proposed a method called Incremental Allocation of Radio Resource between Unicast and Multicast (IARR-UM) to dynamically allocate radio resources to eMBMS based on the current radio access network’s (RAN’s) congestion situation such that some suitable multimedia streaming services are switched to eMBMS and others still use unicast communication. Since the system should use unicast to transmit data as much as possible to maintain the flexibility of eNB’s scheduling/allocating resources to UEs, the proposed IARR-UM method makes a compromise among maintaining the flexibility of eNB’s scheduling/allocating resources to UEs, minimizing the invalid packet rate and increasing UEs’ data rates for video streaming. To effectively use eMBMS to mitigate RAN’s congestion, the proposed IARR-UM method (i) dynamically increases/decreases the amount of radio resources allocated to eMBMS based on the situation of RAN’s congestion, (ii) uses the Knapsack algorithm to select a subset of suitable multimedia streaming services to be eMBMS sessions according to the given amount of radio resources allocated to eMBMS to minimize the invalid packet rate and maximize the video data rate, and then (iii) design a resource allocation pattern, i.e., the Common Subframe Allocation (CSA) Pattern, that can have the lower amount of redundant radio resources allocated to eMBMS. The results of the performance evaluation shown that the proposed method can provide UEs with appropriate radio resources in the cellular network environment and effectively reduce the UEs’ invalid packet rate and increase UEs’ data rates, especially in the higher density of UEs’ situation.

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