臺灣博碩士論文加值系統

在多細胞正交分頻多重接取無線傳輸系統之下鍊傳輸中，當鄰近細胞的基地台使用相同頻帶進行傳輸時，此時細胞與細胞之間會互相造成干擾，使得使用者的通訊品質嚴重的下降，尤其是對在細胞邊緣的使用者更是明顯。因此在多細胞正交分頻多重接取無線傳輸系統中，細胞間干擾的問題是主要影響傳輸品質和整體系統傳輸容量的因素。所以資源分配將會成為很重要的議題，如何適當的去分配資源來有效的降低細胞之間的干擾，以改善細胞邊緣使用的傳輸品質和整體系同的傳輸容量是我們研究上主要的問題。
本論文中，為了解決在多細胞徵交分頻多重接取無線傳輸系統之下鍊傳輸中產生細胞間的干擾問題，在功率分配上我們提出功率區塊的概念並結合交叉嫡演算法來找出最佳的功率分配，並藉由公平的子載波分配演算法來改善細胞邊緣使用者的傳輸品質，且也對細胞內部的使用者保證有一定的傳輸品質，在這兩個前提下提升整體系統的傳輸容量。最後，利用電腦模擬驗證我們的方法是可行的，可以有效的降低細胞間的干擾增加細胞邊緣使用者的傳輸效能和整體系統的傳輸效能。

In multi-cell downlink OFDMA radio network system, users in one cell would suffer from the inter-cell interference caused by frequency reuse, namely co-channel interference. For a practical system, the inter-cell interference seriously decreases the quality of communication, especially for cell-edge users. Therefore, some interference management techniques, such as resources allocation, beamforming…etc., will become an important issue in this system. Therefore, how to allocate resources to enhance cell-edge user performance and total system throughput is the major problem of our research.
In this thesis, for management the inter-cell interference in multi-cell downlink OFDMA radio network system, a power allocation method based on the Cross-Entropy algorithm is proposed to find the sub-optimal solution and corresponding subcarriers allocation. In the system, it is considered that a sum-rate maximization problem while satisfying the target rate of both cell-edge users and cell-interior users. The simulation results show that the proposed method can effectively reduce interference between cells, and increases the transmission performance of cell-edge users and overall system throughput.

論文審定書 i
誌謝 ii
中文摘要 iii
Abstract iv
Chapter 1 Introduction 1
Chapter 2 System Model 5
2.1 The System Model of Multi-Cell OFDMA Downlink Radio Network 5
2.2 Previous Problem 8
Chapter 3 Previous Literatures 12
3.1 Fixed Reuse Factor 12
3.2 Soft Frequency Reuse (SFR) 14
3.3 Partial Frequency Reuse (PFR) 16
Chapter 4 Proposed Method 18
4.1 Problem Formulation 18
4.2 Subcarrier Allocation Algorithm 20
4.3 Power Allocation Concept 23
4.4 Power Allocation Combine with Cross-Entropy Algorithm 24
4.5 Overall Resource Allocation Algorithm 30
Chapter 5 Simulation Results 33
Chapter 6 Conclusion and Future Works 39
6.1 Conclusions 39
6.2 Future Works 40
References 41
Abbreviations 47

[1]D. Gray, “Mobile WiMAX-part 1: A technical overview and performance evaluation,” WiMAX Forum, Feb. 2006.
[2]E-UTRA and E-UTRAN Overall description; Stage 2 (Release 8), 3GPP Technical Specification TS 36.300 V8.7.0, Dec. 2008. [Online]. Available: http://www.3gpp.org.
[3]Requirements for Further Advancements for E-UTRA (LTE-Advanced) (Release 8), 3GPP Technical Specification TR 36.913 V8.0.0, Jun. 2008. [Online]. Available: http://www.3gpp.org.
[4]L. Venturino, N. Prasad, and X. Wang, “Coordinated scheduling and power allocation in downlink multicell OFDMA networks,” IEEE Trans. Veh. Technol., vol. 58, no. 6, pp. 2825–2834, July. 2009.
[5]T. Wang and L. Vandendorpe, “Iterative power and subcarrier allocation for Maximizing WSMR in cellular OFDMA systems,” in Proc. 8th. WiOpt, Jun. 2010, pp. 324–329.
[6]T. Wang and L. Vandendorpe, “Resource allocation for maximizing weighted sum min-rate in downlink cellular OFDMA systems,” in Proc. IEEE Int. Conf. Communications, Cape Town, South Africa, May 2010.
[7]T. Wang and L. Vandendorpe, “Iterative resource allocation for maximizing weighted sum min-rate in downlink cellular OFDMA systems,” IEEE Trans. Signal Process., vol. 59, no. 1, pp. 223–234, Jan. 2011.
[8]F. Minghai, S. Xiaoming, C. Lan, and Y. Kishiyama, “Enhanced dynamic cell selection with muting scheme for DL CoMP in LTE-A,” in Proc. IEEE 71st Veh. Technol. Conf., Taipei, Taiwan, May 2010.
[9]M. Rahman and H. Yanikomeroglu, “Enhancing cell-edge performance: a downlink dynamic interference avoidance scheme with inter-cell coordination,” IEEE Trans. Wireless Commun., vol. 9, no. 3, pp. 1414–1425, Apr. 2010.
[10]H. Zhang, L. Venturino, N. Prasad, and S. Rangarajan, “Distributed inter-cell interference mitigation in ofdma wireless data networks,” in 4th IEEE Broadband and Wireless Access Workshop, New Orleans, LA, USA, Dec. 2008.
[11]Z. Xie and B. Walke, “Enhanced fractional frequency reuse to increase capacity of OFDMA systems,” in Proceedings of the 3rd International conference on New Technologies, Mobility and Security (NTMS), Aachen, Germany, Dec. 2009.
[12]L. Gangming, Z. Shihua, and H. Hui, “A distributed power allocation algorithm with inter-cell interference coordination for multi-cell OFDMA systems,” in Proc. IEEE GLOBECOM, Xi''an, China, Dec. 2009.
[13]V. Corvino, D. Gesbert, and R. Verdone, “A novel distributed interference mitigation technique using power planning,” in Proc. IEEE Wireless Communications and Networking Conference, Apr. 2009.
[14]S. G. Kiani, D. Gesbert, A. Gjendemsjo, and G. E. Oien, “Distributed power allocation for interfering wireless links based on channel information partitioning,” IEEE Trans. Wireless Commun., vol. 8 , no. 6, pp. 3004–3015, June. 2009.
[15]S. G. Kiani and D. Gesbert, “Capacity maximizing power allocation for interfering wireless links: a distributed approach,” in Proc. IEEE GLOBECOM, Washington D.C., USA, Nov. 2007, pp. 1405-1409.
[16]S. G. Kiani and D. Gesbert, “Maximizing the capacity of large wireless networks: optimal and distributed solutions,” in Proc. IEEE ISIT, Seattle, USA, July. 2006, pp. 2501–2505.
[17]D. Gesbert and M. Kountouris, “Rate scaling laws in multicell networks under distributed power control and user scheduling,” IEEE Trans. Inf. Theo., vol. 57, no. 1, pp. 234–244, Jan. 2011.
[18]S. G. Kiani and D. Gesbert, “Capacity maximizing power allocation for interfering wireless links: A distributed approach,” in Proc. IEEE GLOBECOM, Washington D.C., USA, Nov. 2007, pp. 1405–1409.
[19]D. Gesbert and M. Kountouris, “Resource allocation in multicell wireless networks: some capacity scaling laws," in Proc. IEEE WiOpt—RAWNET, Apr. 2007.
[20]M. Pischella and J.-C. Belfiore, “Distributed resource allocation for rate-constrained users in multi-cell OFDMA networks,” IEEE Comm. Lett., vol. 12, no. 4, pp. 250–252, Apr. 2008.
[21]G. Boudreau, J. Panicker, N. Guo, R. Chang, N. Wang, and S. Vrzic, “Interference coordination and cancellation for 4G networks,” IEEE Commun. Mag., vol. 47, no. 4, pp. 74–81, Mar. 2009.
[22]T. Q. S Quek, Z. Lei and S. Sun “Adaptive interference coordination in multi-cell OFDMA systems,” in Proc. IEEE 20th Intern. Symp. PIMRC, Singapore, Sep. 2009, pp 2380–2384.
[23]H. Zhang, Q. Yang, F. Gao, and K. S. Kwak, “Distributed adaptive subchannel and power allocation for downlink OFDMA with inter-cell interference coordination,” in Proc. IEEE GLOBECOM, Miami, USA, Dec. 2010.
[24]I. G. Fraimis, V. D. Papoutsis, and S. A. Kotsopoulos, “A distributed radio resource allocation algorithm with interference coordination for multi-cell OFDMA systems,” in Proc IEEE 21st Intern. Symp. PIMRC, Rio, Greece, Sep. 2010, pp 1354–1359.
[25]G. D. Gonzalez G, M. Garcia-Lozano, S. Ruiz, J. Olmos, and V. Corvino, “Performance evaluation of downlink interference coordination techniques in LTE networks,” in Proc. IEEE 72nd Vehicular Technology Conference Fall, Ottawa, Canada, Sep. 6–9, Sep 2010.
[26]I. G. Fraimis, V. D. Papoutsis, and S. A. Kotsopoulos, “A decentralized subchannel allocation scheme with inter-cell interference coordination (ICIC) for multi-cell OFDMA systems,” in proc. IEEE Global Telecommunications Conf. GLOBECOM, Miami, Florida, USA, Dec. 2010.
[27]M. I. Tiwana, B. Sayrac, and Z. Altman, “Statistical learning in automated troubleshooting: application to LTE interference mitigation,” IEEE Trans. Veh. Technol., vol. 59, no. 7, pp 3651–3656, Sep. 2010.
[28]R. Y. Rubinstein, “Optimization of computer simulation models with rare events,” Eur. J. Oper. Res., vol. 99, no. 1, pp. 89–112, May. 1997.
[29]P. T. de Boer, D. P. Kroese, S. Mannor, and R. Y. Rubinstein, “A tutorial on the cross-entropy method,” Annals of Operations Research, vol.134, no. 1, pp. 19–67, 2005.
[30]R. Y. Rubinstein and D. P. Kroese, The Cross-Entropy Method. Berlin, Germany: Springer-Verlag, 2004
[31]L. Neung-Hyung and B. Saewoong, “Dynamic channel allocation using the interference range in multi-cell downlink systems,” in Proc. IEEE. WCNC, Hong Kong , Mar. 2007, pp. 1716–1721.
[32]H. Dahrouj, and W. Yu, “Multicell interference mitigation with joint beamforming and common message decoding,” IEEE Trans. Commun., vol. 59, no. 8, pp. 2264–2273, Aug. 2011.
[33]H. Dahrouj, and W. Yu, “Coordinated beamforming for the multicell multi-antenna wireless system,” IEEE Trans. Wireless Commun., vol. 9, no. 5, pp. 1748–1759, Aug. 2010.