在進階長期演進網路中實現裝置與裝置直接通訊

隨著行動通訊裝置如智慧型手機與平板電腦的普及，現今人們可以隨時隨地上網以及使用各種應用程式。然而，現行的第三代行動通訊網路(3G)已經不足以應付龐大的高速傳輸資料需求。為了提供更高的流量以及更好的服務品質，第三代合作夥伴計畫(3GPP)提出了進階長期演進網路(LTE-A)做為第四代行動通訊網路(4G)的標準。而裝置與裝置直接通訊(Device-to-device communication)是進階長期演進網路用來提升網路容量與無線資源使用效率的關鍵技術之一。由於資料流不需經過網路的基礎建設，因此使用裝置與裝置直接通訊來傳輸資料可以讓傳輸更有效率，進而提升整體的網路容量。除此之外，為來裝置與裝置直接通訊將有非常多的發展機會。舉例來說，適地性服務(Location-based services)以及社群應用(social proximity) 使用裝置與裝置直接通訊可以消耗較少的無線資源並且產生較小的延遲。雖然裝置與裝置直接通訊可以帶來許多益處，要在進階長期演進網路中實現裝置與裝置直接通訊仍然有相當多的挑戰。從營運商的角度來看，如果無法產生額外的收益，就不會吸引營運商實現裝置與裝置直接通訊。而從使用者裝置(User equipment)的角度出發，只有當使用者裝置能夠發現鄰近的裝置後才能夠實現裝置與裝置直接通訊。因此，本研究從營運商與使用者裝置的角度出發，探討裝置與裝置直接通訊。首先，我們推導即用即付方案與吃到飽方案的需求函數，並且分析營運商的收益。由數值分析與模擬的結果都顯示，裝置與裝置直接通訊不但能增加近1/3的網路容量，更能為營運商帶來至多21%的額外營收。此結果能提供營運商很強烈的動機去實現裝置與裝置直接通訊。另一方面，我們提出一個隨機存取的裝置偵測協定讓使用者裝置得以偵測鄰近的其他裝置。此裝置偵測協定需要使用者裝置隨機傳輸發現訊號去宣告它的存在。為了讓裝置偵測使用的無線資源最小化，我們也提出了一個能夠根據裝置數目動態分配資源的演算法。由我們的數值分析與模擬結果顯示，我們的裝置偵測協定能夠只使用基地台1%的上傳資源去達到非常高的偵測成功機率(e.g., 99%)。

關鍵字

第四代行動通訊網路；進階長期演進技術；裝置與裝置直接通訊；營運商收益分析；裝置偵測協定；動態資源分配

並列摘要

With the prevalence of mobile devices such as smart phones and tablets, people can access the Internet and use various applications and services anytime, anywhere. However, the existing 3rd generation (3G) cellular technologies cannot support the large demand of high-speed transmission. To support higher throughput and better quality of service, long term evolution advanced (LTE-A) has been proposed by 3rd Generation Partnership Project (3GPP). Device-to-device (D2D) communication is one of the key technologies in LTE-A for improving network capacity and resource utilization. With D2D communication, data transmission can be more efficient and thus the overall system capacity can be increased since the data does not go through the infrastructure. Furthermore, there are many opportunities for D2D communication. For example, location-based services and proximity social applications with D2D communication can use less resource and produce smaller latency. Although D2D can bring many benefits, there are still many challenges to implement D2D in LTE-A networks. From operators' perspective, D2D would not be an appealing technology if no additional revenue can be generated. From user equipments' perspective, D2D transmission can only be enabled if the UEs in the vicinity can be discovered. In this thesis, we consider D2D communication from both operator's and UEs' perspective. First, we derive the demand functions of pay-as-you-use and flat-rate plans, and analyze the revenue of an operator. Our numerical analysis and simulation results show that D2D not only increases nearly 1/3 of capacity but also brings up to 21% additional revenue for operators. The results provide operators with a strong incentive to implement D2D communication. Next, a random-access discovery protocol is proposed for UEs to discover other nearby UEs. The proposed protocol requires UEs to advertise their presence by random beacon transmission. In order to minimize resource consumption on discovery, an adaptive resource allocation algorithm based on the number of requesting D2D UEs is also proposed. Our numerical analysis and simulation results show that a very high discovery probability (e.g., 0.99) can be achieved by using only 1% of the eNB's uplink resources.

並列關鍵字

4G ； LTE-A ； Device-to-Device (D2D) communication ； operator revenue analysis ； discovery protocol ； dynamic resource allocation

參考文獻

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ference limited area for device-to-device uplink underlaying cellular networks,”Wireless Communications, IEEE Transactions on, vol. 10, no. 12, pp. 3995–4000,

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在進階長期演進網路中實現裝置與裝置直接通訊

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