長期演進（Long Term Evolution；LTE）技術為第3代合作夥伴計畫所制定的無線行動網路標準；長期演進技術升級版（Long Term Evolution-Advanced；LTE-A），為LTE的演進版本。在LTE-A新增的技術中，異質網路（Heterogeneous networks；HetNets）是於大型網路內傳輸功率最高的大型基地站（Macro eNB）下，在訊號範圍死角或人口稠密的地方，架設傳輸功率較小的超微型基地站（Pico eNB）、毫微微型基地站（Femto eNB）或中繼站（Relay），提升用戶端的通訊品質。
LTE分時多工系統中規範7種上下行時槽比例配置可供使用，但並未能說明可以如何有效率的使用7種配置。而且LTE中存在著細胞間干擾，尤其在分時多工系統中更必須注意訊框交錯干擾的存在。訊框交錯干擾是由兩個相鄰區域的TDD系統使用不同的上下行時槽比例配置時，在部分的時段會出現『一個系統在進行下行傳輸，另一系統在進上行傳輸的訊框交錯干擾』的干擾， 所以在異質網路下，基地站之間動態使用不同上下行時槽比例配置，容易出現訊框交錯干擾的問題，造成傳輸的資料速率下降的現象。
為了解決上述問題，本論文提出以4種模式來動態調整上下行時槽比例配置的方法，考量在異質網路的環境中，彈性使用規範中的上下行時槽比例配置來提高系統的傳輸量，並針對訊框交錯的影響作改良。經模擬結果顯示，在各效能評估項目上，本論文提出動態調整上下行時槽比例配置的方法能得到較佳的傳輸量且解決現有分時多工系統不能靈活調整上下行時槽比例配置的情況。

Long Term Evolution (LTE) is a standard for wireless mobile network from The 3rd Generation Partnership Project Agreement (3GPP). Long Term Evolution–Advanced (LTE-A) is evolutionary version from LTE. LTE-A add some new technologies, one of which is Heterogeneous networks (HetNets). HetNets can build Pico eNB (eNodeB), Femto eNB and Relay whose transmission power is less than Macro eNB in Macro network to improve the communication quality on cell edge or hot spot users. However, when different kind of eNB transmit signals to their UEs (User Equipment) using same frequency at the same time, and two of UEs are in each other's transmission signal range, that will cause Co-channel Interference to make two of UEs can’t accurately receive the transmitted signals from their service eNB.
LTE TDD system specification seven kinds of uplink and downlink configuration, but failed to say how you can efficiently use the seven kinds of configurations. And LTE interference between cells exist in, especially in the TDD system is more important to note the presence of the frame interlace interference. When a different frame interlace interference ratio of the vertical line of the groove is configured by the two adjacent regions of the TDD system used in a portion of the time there will be "during a downlink transmission system, the other system uplink transmission frame interleaved into the interference ", so in a heterogeneous network, the dynamic between the base station using a different proportion of uplink and downlink configuration problem to cause Crossed Timeslot Interference, resulting in a decrease in the transmission data rate of the phenomenon.
In order to solve the above problems, this paper proposes four models to dynamically adjust the ratio method and the uplink and downlink slot configuration, considering the heterogeneous network environment, flexibility of use in the uplink and downlink slot configuration to increase the proportion of traffic system and make improvements for frame interleaving impact. The numerical results show that the performance evaluation of each project, this paper proposes a method to dynamically adjust the ratio of the uplink and downlink configuration to get better traffic and solve the existing TDD systems can be flexibly adjusted the uplink and downlink configuration proportion situation.

[1] 3GPP TSG RAN WG1：”Evolved Universal Terrestrial Radio Access (E-UTRA),Physical Channels and Modulation (Release 11) ” 3GPP TS 36.211, Dec. 2012
[2] 3GPP TSG RAN WG1：”Evolved Universal Terrestrial Radio Access (E-UTRA),Further advancements for E-UTRA physical layer aspects (Release 9) ” 3GPP TR 36.814, Mar. 2010
[3] Dahlman Erik, Parkvall Stefan and Skold Johan.(2011)”4G LTE/LTE-Advanced for Mobile Broadband”. Academic Pr
[4] "4G LTE Advanced Relay" [Online]. Available: http://www.radio-electronics.com/info/cellulartelecomms/lte-long-term-evolution/4g-lte-advanced-relaying.php
[5] "3GPP LTE - Evolved UTRA - Radio Interface Concepts" [Online]. Available: http://ecee.colorado.edu/~ecen4242/LTE/radio.htm
[6] " LTE:Physical layer Concept (Frame structure, Resource Block and Resource Element 概念) " [Online]. Available: http://xdxdd.blogspot.tw/2012/11/ltephysical-layer-concept-frame.html
[7] " LTE: LTE:Channel Quality Indicator(CQI) feedback " [Online]. Available: http://xdxdd.blogspot.tw/2012/09/lte-ltechannel-quality-indicatorcqi.html
[8] 3GPP TSG RAN WG1：”Evolved Universal Terrestrial Radio Access (E-UTRA),Physical layer procedures (Release 11) ” 3GPP TS 36.213, Feb.2012
[9] M. Porjazoski, and B. Popovski, "Contribution to analysis of Intercell interference coordination in LTE: A fractional frequency reuse case," 2010 Global Mobile Congress (GMC), vol., no., pp.1,4, 18-19 Oct. 2010
[10] Du Yang, J. Bastos, et al. "Location-aided round robin scheduling for fractional frequency reused LTE-A relay network," 2012 IEEE 17th International Workshop on Computer Aided Modeling and Design of Communication Links and Networks (CAMAD), , vol., no., pp.11,15, 17-19 Sept. 2012
[11] Jianguo Liu, Dongyao Wang, et al."Inter-cell interference coordination based on soft frequency reuse for relay enhanced cellular network," 2010 IEEE 21st International Symposium on Personal Indoor and Mobile Radio Communications (PIMRC), vol., no., pp.2304,2308, 26-30 Sept. 2010
[12] Yiwei Yu, E Dutkiewicz, et al. "Performance analysis of soft frequency reuse for inter-cell interference coordination in LTE networks," 2010 International Symposium on Communications and Information Technologies (ISCIT), vol., no., pp.504,509, 26-29 Oct. 2010
[13] D Ogata, A Nagate and T Fujii , "Multi-BS Cooperative Interference Control for LTE Systems," 2012 IEEE 75th Vehicular Technology Conference (VTC Spring), vol., no., pp.1,5, 6-9 May 2012
[14] T Novlan, J.G. Andrews, et al."Comparison of Fractional Frequency Reuse Approaches in the OFDMA Cellular Downlink," 2010 IEEE Global Telecommunications Conference (GLOBECOM 2010), vol., no., pp.1,5, 6-10 Dec. 2010
[15] Manli Qian, Hardjawana W., et al. "Inter-cell interference coordination through adaptive soft frequency reuse in LTE networks," 2012 IEEE Wireless Communications and Networking Conference (WCNC), vol., no., pp.1618,1623, 1-4 April 2012

[16] Jun Wang, Jianguo Liu, et al. "Load Balance Based Dynamic Inter-Cell Interference Coordination for Relay Enhanced Cellular Network," 2012 IEEE 75th Vehicular Technology Conference (VTC Spring), vol., no., pp.1,5, 6-9 May 2012
[17]Chang, Pei, et al. "Interference analysis and performance evaluation for LTE TDD system." Advanced Computer Control (ICACC), 2010 2nd International Conference on. Vol. 5. IEEE, 2010.
[18]Wang, Yufeng, et al. "Performance evaluation of flexible TDD switching in 3GPP LTE system." Sarnoff Symposium (SARNOFF), 2012 35th IEEE. IEEE, 2012.
[19]Khoryaev, Alexey, et al. "Performance analysis of dynamic adjustment of TDD uplink-downlink configurations in outdoor picocell LTE networks." Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT), 2012 4th International Congress on. IEEE, 2012.
[20]Ji, Hyoungju, et al. "Dynamic resource adaptation in beyond LTE-A TDD heterogeneous networks." Communications Workshops (ICC), 2013 IEEE International Conference on. IEEE, 2013.
[21] 3GPP TR 36.814, "Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Further advancements for E-UTRA physical layer aspects "