第五代行動通訊技術(5G)受到了許多重視，且目前仍被許多研究學者探討中。具前景的軟體定義網路(soft-defined network, SDN) 技術將是5G無線網絡設計中的關鍵組成部分。本論文針對軟體定義實體層中接收端(receiver end of soft-defined physical layer, PHY RX)平行化的實現以及上傳的加速來作探討和驗證。
LTE standard 制定子框架(subframe)單位為一個傳輸時間區間Transmission Time Interval (TTI)，也就是規定PHY處理一個subframe的時間需要在1 millisecond (ms)以內完成。若無法在規定的1 ms內處理完當前subframe，則會啟動重傳Hybrid Automatic Repeat request (HARQ)機制。若是一直無法在1 ms內處理完造成多次的重傳，會導致網速下降，甚至基地臺當機(eNB crash)。以基地臺服務多個UEs為考量，在原本沒有平行處理的架構下，頻寬5 MHz下已經無法完全服務多使用者(multi users)。若是使用更大的頻寬和更多的資源區塊(resource block, RB)，提供multi users的服務將會更不穩定，在頻寬20MHz能上線的UEs上限只有2個UEs。
因此，在本研究中我們提出應用於Soft PHY RX的多執行續(multithread)的平行化架構。將PHY層中RX的流程重新編排，利用Pthreads (POSIX threads)來實作我們的RX的平行流程，將CPU的8條threads 全部一起使用，不論是在處理PHY RX 或是UEs的連線，皆把原本的架構中非必要的循序運作的流程改成平行處理，使得PHY層執行的效率更好以提高傳輸量。實驗顯示，經由本研究所提出平行處理的方法，PHY RX的上傳的速度將提升至原本速度的6.3倍，基地臺也將可以服務更多UEs。

The 5G (5th generation mobile networks) techniques have attracted a lot of attention and are still under investigation by many researchers. The soft-define network (SDN) has been proposed as one of the promising techniques, which will be a key component in the design of 5G wireless networks. This thesis mainly discusses and verifies the implementation of the parallel processing and the acceleration of uploading at the receiver end of soft-defined physical layer (PHY RX).
The LTE standard defines a subframe unit as a Transmission Time Interval (TTI), that is, the time required for the PHY to process a subframe needs to be completed within 1 millisecond (ms). If it has not been processed within 1 ms, it will cause multiple retransmissions, resulting in a drop in network speed and even a base station crash (eNB crash). Considering that multiple base stations serve multiple UEs, under the architecture that is not processed in parallel, it is impossible to fully serve multiple users at a bandwidth of 5 MHz. If one uses a larger bandwidth and more resource blocks (RBs), the service that provides multi users will be more unstable. At 20MHz, the upper limit of UEs that can be online is only 2 UEs.
Therefore, in this study we propose a multi-thread parallelization architecture for Soft PHY RX. Reorganize the RX process in the PHY layer and use Pthreads (POSIX threads) to implement our RX parallel process. We use all 8 threads of the CPU together. Whether processing the PHY RX or UEs connection, the process of non-essential sequential operation in the original architecture is changed to parallel processing, so that the PHY layer performs better to improve the transmission amount. Experiments show that, through the parallel processing method proposed by this research, the upload speed of PHY RX will increase to 6.3 times of the original speed, and the base station will also be able to serve more UEs

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