| Summary: | 碩士 === 國立臺北大學 === 通訊工程研究所 === 104 === In recent years, Wireless Local Area Networks (WLANs) have undergone rapid development. We will improve upon the previous IEEE802.11ac standard. Further, we will extend this standard to the IEEE 802.11ax technique for the latest generation of WLANs. In our research we will use an 802.11 WLAN and apply a Space-Time Block Code (STBC).
The 802.11ac system is uses the Multiple-Input Multiple-Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) techniques. The channel is an important factor with regard to the effects of transmission and reception on signals. Thus, we contrapose Wireless Open Access Research Platform (WARP) construction to conduct research and must correspond to the hypotheses of algorithms and the Signal Noise Ratio (SNR) theorem. Using a Single Tree Search (STS) as an optimal detection algorithm, along with approximation Maximum Likelihood (ML) detection, Very Fast (VF) detection has a wide range of tradeoffs between performance and complexity, and is also a suboptimal detection algorithm. Zero Forcing (ZF) is a poor detection algorithm.
Research on 802.11ac extends to 802.11ax. The 802.11ax system is MIMO and uses the Orthogonal Frequency Division Multiple Access (OFDMA) technique. Then, we use one transmitter and two receivers to conduct a 2 × 1 Space-Time Block Code (STBC) experiment. The two receivers Rx A and Rx B receive signals to distribute the resources for each subcarrier, and select each subcarrier’s minimum Bit Error Rate (BER) for the main receiver. Then, we compare the total subcarrier BERs of Rx A and Rx B and the main receiver. Which results is total subcarriers BER of the main receiver the lower. Thus, this experiment can effectively reduce the total BER of the subcarriers.
Finally, this thesis use WARP form Mango Communications to implement an 802.11 WLAN system environment. We use realistic data transmission and channel detection with estimation. Therefore, our research validates this technique, which is applicable not only in the simulation but also in the real word.
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