為了支援在未來在5G網路環境中， 行動寬頻流量之需求將為現在的一千倍， 僅靠現有的4G LTE(Long Term Evolution; LTE)技術勢必將無法提供如此高的流量需求，因此國際標準組織與廠 商以LTE網路為核心， 整合其他異質網路， 以提供更高的行動數據流量。本論文提出LTE與WiFi 異質網路聚合的設計與實現方法， 以LTE網路為主，並且將資料分流至WiFi網路，讓整個系統具 備更高的傳輸頻寬，在實現的系統架構上，在鏈路層（Link Layer）作頻寬聚合，根據即時的通 道特性，來分配無線資源，獲得較佳的系統效能；基於LTE與WiFi網路本質上的不同，使得在進 行資料封包接收時，會有封包失序(packet out of order)的問題發生，我們利用現有的LTE封包重 置機制來解決該問題，進而提升資料封包的可靠度與減少資料封包重送的發生。

Since current 4G LTE technology cannot support the 1000x mobile traffic volume which is the requirement of the fifth generation (5G) network, the standard development organizations and the manufactures integrate the LTE and the other heterogeneous networks so that the traffic volume will be improved. This paper proposes the method to design and implement the bandwidth aggregation in LTE-WiFi heterogeneous networks. We use the LTE network as the primary interface and offload the data to the WiFi network, as the secondary interface, in order to perform higher data bandwidth than only using one of the LTE or WiFi network. We implement the method in the link layer so that we can coordinate the radio resources accordi ng to the channel condition and get better system performance. Due to the difference of the LTE and WiFi networks, we encounter the problem of packet out of order when receiving data packets. This problem is solved with the reordering mechanism in LTE technology; as a result, we can enhance the packet reliability and reduce the number of packet retransmission.