為改善高鐵列車車廂WiFi網路各車廂存取點(Access Point， AP)之間的封包遺失率(Packet Loss Ratio，PLR)與突發性的TCP 暫停(Stuck)等問題進而提供穩定的車廂網路通訊效能，因此我們針對車廂間與車廂內的網路通訊連結方式進行設計， 車廂間AP對AP的傳輸連結是使用無線分散式系
統(Wireless Distribution System，WDS)來進行， 其所使用的頻帶為5GHz， 標準規格則設定為IEEE 802.11a，而車廂內AP對User STA(User Station，用戶站)的傳輸連結是使用基本服務集合(Basic Service Sets， BSS)來進行， 其所使用的頻帶為2.4GHz， 標準規格則設定為IEEE 802.11g。在估算出理想通道狀態下的WDS 802.11a與BSS 802.11g無封包遺失之最大傳輸率(Maximum Zero Drop Throughput，MZDT)之後，利用高鐵靜止環境狀態來進行驗證測試，目前車廂間WDS 802.11a連結與傳輸驗證的部分， 僅有第七車與第八車之間WDS連結的上行鏈路有0.9%的封包遺失率， 其餘車廂的WDS連結皆能達到MZDT等於24.6Mbps且遺失率為零的驗證條件，而車廂內BSS 802.11g連結與傳輸驗證的部分， 列車各車廂內的BSS連結皆能達到MZDT等於27Mbps且遺失率為零的驗證條件。

To improve the degradation of Packet Loss Ratio (PLR) and sudden TCP stuck among the installed APs in train for WiFi networks and to provide stable network performance, we design the architecture of In-train network, which includes an inter-car network and an intra-car network. For the inter-car network,Wireless Distribution System (WDS) with 5GHz frequency band and IEEE 802.11a specification is adopted to perform AP-to-AP transmission. For the intra-car network, Basic Service Sets (BSS) with 2.4GHz frequency
band and IEEE 802.11g specification is adopted to perform AP-to-User STA transmission. After estimating the Maximum Zero Drop Throughput (MZDT) of WDS 802.11a and BSS 802.11g links for ideal channel, we can verify the performance in static train environment. According to the testing results, only the WDS link between Car7 and Car 8 has about 0.9% PLR degradation and all other WDS links which passed the criteria of MZDT can achieve the throughput of 24.6Mbps and 0% PLR. All BSS 802.11g links passed the criteria of MZDT can achieve the throughput of 27Mbps and 0% PLR.