LTE-A無線系統下行鏈路之協調多點式資源分配

Abstract

隨著新興無線通訊服務的增加，對於高速無線傳輸的需求量也日漸提高。為了要達到高速無線傳輸，長期演進技術進化系統 (Advanced long term evolution LTE-advanced) 提出多種解決技術來因應。其中，協調式多點傳輸/接收(Coordinated multi-point transmission/reception CoMP)的技術適用於增加系統傳輸速率。此外，在現今多媒體通訊的環境下，傳輸服務品質(Quality of service QoS)的保證是一個很重要的議題。因此，一個能有效利用系統資源且保障傳輸服務品質而使得系統傳輸速率增大的無線資源分配演算法是必要的。 在本篇論文當中，我們提出了一個協調多點式無線資源分配 (CoMP-based radio resource allocation CRRA)方法使得系統傳輸速率達到最佳且滿足傳輸服務品質。協調多點式傳輸可使用多天線來服務使用者，可因此獲得合作增益(Cooperative gain)或是多使用者多樣性增益(Multi-user diversity gain)。在提出的資源分配方法中，我們給予不同服務層級之使用者不同之服務順序基準，再加上使用者緊急程度，即可決定服務順序及最小傳送速率。經過此步驟後，再經由兩階段，有不同目的──服務品質導向及有效傳輸速率導向的演算法即可將資源有效率的分配。模擬結果顯示出協調多點式無線資源分配，不論在系統有效傳輸速率、消耗之傳送功率及服務品質方面皆可獲得不錯的增益值。

According to the increase of state-of-the-art wireless transmission services, the demand of high-speed transmission rate is getting larger. There are several key technologies proposed for LTE-advanced system to achieve higher transmission rate requirements. Coordinated multi-point transmission/reception (CoMP) is mainly utilized to increase the system throughput. In addition, guarantee of quality of service (QoS) is another critical issue. Therefore, a well-designed and QoS-guaranteed radio resource allocation scheme is required to efficiently utilize the system resource. In this thesis, we proposed a CoMP-based radio resource allocation (CRRA) scheme to optimize system throughput and achieve the QoS requirements. Since the system with CoMP transmission uses several antennas to serve users, it can obtain cooperative or multi-user diversity gain. In the CRRA algorithm, the service order and the least transmission rate are calculated in the priority and rate assignment strategy. After that, a heuristic CRRA algorithm is utilized to allocate resource efficiently with lower complexity. In simulation results, we can conclude that the CRRA scheme outperforms the conventional algorithms in terms of system throughput, average transmission power per bit, and satisfaction of QoS requirements.