C-RAN
Basically, the ISP considers to adopt the technology of the LTE-A as below
1. CA - Carrie Aggregation - Three types: (a) Intra-band Contiguous (b) Intra-band Non-contiguous (c) Inter-band Non-contiguous
2. MIMO
MIMO為LTE-A帶來更高階的4×4或8×8，但也因此造成裝置支援的問題，目前尚無支援4×4 MIMO的智慧型手機。
當然MIMO不須在發送器以及接收端取得平衡。美國T-Mobile支援4×2 MIMO，即在基地台建置4條天線，在裝置端建置2條。4×2 MIMO仍然可以改善網路效能，效果在下行鏈路尤為可觀，裝置得以傳送訊號至四條不同天線，而不只有兩條。
美國電信商Sprint已部署支援8×8 MIMO的LTE TDD基地台一段時間。提供此類無線電系統的廠商有阿爾卡特朗訊(Alcatel-Lucent)、諾基亞通信，以及三星(Samsung)。中國移動也正著手建置類似的無線電系統，除Alcatel-Lucent和諾基亞外，也和愛立信(Ericsson)、華為和中興通訊合作。然而Sprint因為裝置支援問題，尚未開通8×8 MIMO，目前僅為其LTE TDD傳輸擴展4×2 MIMO。
雖然MIMO確實能增加網路容量，卻無法帶來和載波聚合一樣的益處。首先，因為智慧型手機的天線空間已經相當有限，無法再容納MIMO。其次，營運商須要增加天線，甚至可能要添置無線電系統才能支援MIMO，這些流程帶來的額外成本都高於只須進行軟體升級的載波聚合。
3. CoMP
CoMP is a technology that prevents base station interference and abrupt call disconnections in coverage boundary areas by enhancing signal strength, the lack of which leads to a significant drop in data transmission speed, and CA is a technology that provides twice or faster data rates by utilizing multiple frequency bands at the same time.
coordinated Multipoint (CoMP) Transmission – Formalized in 3GPP Release 11, CoMP would be another key characteristic of a true LTE Advanced network. In a Coordinated multipoint transmission and reception scenario, multiple eNodeBs work with each other dynamically to avoid interference with other transmission signals. This leads to a better utilization of system resources and an enhancement of both network coverage and quality for cell edge users.
CoMP技術能讓終端用戶裝置同時與多處無線電端點通訊。這使得數站基地台能藉此合作，在上、下行鏈路共同分配網路資源並傳送資料；此外該技術還能在終端用戶裝置與數站基地台通訊時，改善邊緣地區的效能。
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| 圖4 CoMP圖示 |
與其讓不同基地台的訊號帶來干擾且削弱網路效能，CoMP反倒能讓那些基地台共同合作改善邊緣地區效能。圖4為CoMP基本功能圖示。
CoMP的標準化從3GPP第11版本開始，並在第12版本持續進行。CoMP最大的問題在於不同基地台無線電系統之間的協調，需要低延遲的網路回傳技術。理想狀態下，這能透過C-RAN解決，但因為缺少能連接各個無線電接頭(Radio Head)的光纖，使得大部分的營運商難以進行部署。
CoMP最初的建置在上行鏈路完成，不須經標準化，或是裝置端的協調和調整。由於下行鏈路須要經過完整協調，因此建置過程將較難執行。
下行鏈路協調的首批建置將於頻段內進行，使用與單一頻帶單位連接之多重無線電單位的專用基地台，此舉將可能會限制涵蓋範圍。在3GPP第12版本批准之前，頻段內CoMP距離商業化仍有幾年的路要走，屆時才能解決多處基地台間網路回傳延遲的問題。
4. eICIC- Enhanced Inter-Cell Interference Coordination – eICIC will be the primary interference management and mitigation procedure adopted in the LTE-A network. It is typically used in a heterogeneous network where both macro and pico cells transmit and receive data at the same time. The weaker signal from the smaller cell can be easily overpowered by the stronger signal from the larger cell. In eICIC, certain subframes are transmitted by the macro cell without any data. These almost blank subframes (ABS) are low power control channels. The users in the pico cell area then communicate with their base station during such blank subframes. This minimizes the interference between the macro and pico cell on both traffic and control channels. Advanced interference mitigation schemes have been used in LTE networks, but with the increasingly high density of wireless network cells, more sophisticated schemes like eICIC are required
eICIC在網路方面的角色和CoMP類似，兩者都能降低基地台間的干擾，並改善邊緣區域效能。兩種技術之間最大不同在於，eICIC是利用相似頻道解決小型基地台與大型基地台間的干擾；而CoMP則著重在大型基地台間的干擾。
