現行的分時多工(time-division duplex, TDD)無線通訊， 其上行/下行資源的比例通常是以半穩態
(semi-static)的方式由基地台利用系統資訊廣播的方式告知用戶設備。然而這種方式並無法及時地
滿足且符合使用者設備多變的流量需求。因此，快速地依實際需求調整上下行資源的分時多工無線通訊系統概念便產生。然而，為了向後相容於舊版本用戶設備，這種具流量適應的分時多工無線通訊系統需同時使用不同的上行下行資源組態來服務不同版本的用戶。在這樣的狀況下，不同版本用戶所需回傳的混合式自動重傳請求(Hybrid Automatic Repeat Request, HARQ)訊息將會發生資源衝突的現象， 本文將探討此問題並提出有效的處理方案。

For a TDD (Time Division Duplexing) communication system, the uplink (UL)/downlink (DL) resource ratio is semi-statically assigned by broadcasting corresponding system information. However, semi-statics
allocation cannot match fast varying traffic characteristics and environments. Thus, changing the UL/DL configuration with a lower periodicity is considered. For a TDD system with traffic adaptation, the legacy UE is configured with a UL/DL configuration according to the system information. The additional configuration is a real configuration operated by the eNB, and the eNB provides services to both the legacy UE and the
advanced UE according to the additional configuration. However, when the legacy UE and the advanced UE are configured with difference UL/DL configurations, a collision of hybrid automatic repeat request (HARQ) resources may occur if the legacy UE and the advanced UE intend to transmit HARQ feedbacks in a same UL subframe. Thus, how to solve the collision of the HARQ resources caused due to differ ent UL/DL configurations of the legacy UE and the advanced UE is an important topic to be discussed.