我們設計一適用於室內之高生產量的4×4多輸入輸出正交分頻多工調變的無線通訊傳輸系統，並將其硬體於FPGA開發板中實現完成。並且此無線通訊收發機的傳送機與接收機星座圖對應皆可支援到64QAM，多輸入輸出系統支援到4根傳送天線對應4根接收天線。此無線收發機可支援三個不同子載波數的正交分頻多工調變系統分別對應到128、256與512個子載波模組。接收機設計中，我們在時域包含符元邊界偵測與小數載波頻率偏移做估測與補償的相關硬體。在頻域上，我們也有針對取樣時脈偏移與殘餘載波頻率偏移做估測與補償做追蹤的相關機制，以預防取樣時脈偏移與殘餘載波頻率偏移降低此套無線通訊系統的系統效能。另外，多輸入輸出系統訊號解調我們採用一次排序後QR分解加上K-best球面解碼器來還原原始資料，我們所採用的多輸入輸出系統在系統模擬上可以得到不錯的效能。在硬體實現模擬結果方面，此套系統在操作時脈為55MHz的情況下可以正常運作，其傳輸輸速率可達到891Mbps。 Implementation of a 4×4 MIMO-OFDM baseband transceiver on FPGA platform for indoor high throughput wireless communication systems is presented. Both the transmitter and the receiver support 64-QAM constellation and spatial multiplexing up to four antennas. The system has three operation modes corresponding to different FFT sizes of 128, 256, and 512 points. At the receiver, we incorporate symbol timing detection and carrier frequency offset (CFO) acquisition modules in the time domain. The subsequent CFO and sampling clock offset (SCO) tracking mechanism is also designed in the frequency domain to prevent from their severe destruction of the system performance. In addition, MIMO signal detection is accomplished by one-time sorted QR decomposition and K-best sphere decoding. Simulation results are provided to show the satisfying system performance. From hardware implementation results, the system can work at 55-MHz sampling frequency for ISE Post-Rout result, which is capable to offer 891Mbps transmission rate.
