臺灣博碩士論文加值系統

在行動通訊網路中，透過各基地台間的無線電訊號覆蓋來增進無線服務覆蓋率。對無線下傳資料服務來說，基地台間的無線電覆蓋可提供虛擬軟式交遞機會，但也增加基地台間的訊號干擾，以至於減少可獲得的資料率。在本論文中，我們將介紹一種在下傳資料服務下的基地台功率控制策略。藉由一個門檻的假設，動態調整基地台功率來降低基地台間的訊號干擾，以期增加系統總處理量並有效處理空間上及時間上熱點基地台問題。另外，為了減少基地台變動功率的頻率，我們也提出另一種方式，即假設兩個門檻來降低此種磁滯效應。由數據顯示出我們所提的功率控制策略能夠有效的增加系統總處理量、減少延遲時間並且解決空間、時間上的熱點問題。

In cellular networks, wireless service coverage is improved through partly radio coverage overlays between neighboring access point transmitters (APTs). For wireless forward link data services, the overlay provides virtual soft handoff opportunities, but also introduces significant intercell interference which reduces feasible service data rate. In this thesis, we investigate APT power level control strategy for wireless forward link data services. We assume that the transmission power of each APT is adjustable between a default high level and a low level if necessary. The objective is not only to improve system throughput by reducing intercell interference but also to adapt APT power level activity to alleviate the impact of temporal and spatial traffic variation among cells. These are achieved by utilizing a simple search-and-lock algorithm which coordinates APT power level activity essentially according to traffic loads and traffic spatial distributions. Moreover, we consider that the frequency of switching APT power levels is an important measure of system complexity. We then propose a hysteresis approach using two thresholds to damp down the frequency of changing APT power activity patterns besides using a single threshold. In addition, we study the effect of adapting APT power level activity on the behavior of the proportional fair scheduler for forward link data services. Our study shows that proposed power level control strategies are able to yield many favorable performance features in terms of throughput, latency, temporal and spatial traffic hot spot relief, in particular when path loss exponent is small or traffic loads are distributed increasingly toward cell boundaries. Additionally, service opportunities by the proportional fair scheduler drift toward users in the far field where fading gains from changing antenna power patterns are more significant.

Chapter 1 Introduction 1
1.1 Background 1
1.2 Objective 3
1.3 Related Work 5
1.4 Thesis Organization 6
Chapter 2 System Model and Power Control Policies 7
2.1 System Model 7
2.2 Path Loss Model、SINR Expression and Peak Data Rate function 8
2.3 Packet Scheduling Policy 9
2.4 Power Control Policies 10
2.4.1 Simple Power Control Scheme 11
2.4.2 Adaptive power level control with one threshold 12
2.4.3 Adaptive Power level control with two hysteresis thresholds 15
Chapter 3 Simulation Model 17
3.1 Simulation model 17
3.2 Pseudo Code for power control schemes 20
Chapter 4 Numeric Result 24
4.1 The effect of stationary traffic 25
4.2 The effect of traffic hot-spot 83
4.3 The effect of nonhomogeneous traffics 113
4.4 The system without AT direction information 153
4.5 The effect of average data size 239
4.6 The effect of thresholds 256
4.6.1 the threshold ρ in AP 256
4.6.2 the threshold φ in APH 261
Chapter 5 Conclusion and Future Work 273
References 275

[1] A. Jalali, R. Padovani, R. Pankaj, “Data throughput of CDMA-HDR a high efficiency-high data rate personal communication wireless system”, in Proc. Vehicular Technology Conference (VTC)-Spring, vol. 3, pp. 1854- 1858, May, 2000.
[2] D.-J. Lee, D.-H. Cho, “Data transmission scheduling considering short-term fading for transmit power reduction in CDMA systems”, IEEE Transactions on Vehicular Technology, pp , 2002.
[3] H. Kim, K. Kim, Y. Han, J. Lee, “An efficient scheduling algorithm for QoS in wireless packet data transmission”, in Proc. Personal, Indoor and Mobile Radio Communications (PIMRC), pp 2244-2248, 2002.
[4] H. Kawai, S. Ohkubo, T. Otsu, “Transmit power and window control to reduce inter-user interference in CDMA cellular packet systems”, in Proc. IEEE Wireless Communications and Networking Conference (WCNC), pp 552-557, 2003.
[5] Jaber A. Khoja, Jonathan W. Bredow, “Capacity management of the forward link of CDMA systems”, in Proc. Wireless Personal Multimedia Communications (WPMC), pp 1152-1156, 2002.
[6] J-G Choi, H-K Lim, Y-J Choi, and S. Bahk, “Downlink throughput enhancement by combining packet scheduling with a simple power control scheme in CDMA data networks”, in Proc. IEEE Mobile and Wireless Communications Network(MWCN), vol. 1, pp. 93- 97, Sep. 2002.
[7] Jack M. Holtzman, “Asymptotic analysis of proportional fair algorithm”, in Proc. Personal, Indoor and Mobile Radio Communications (PIMRC), vol. 2, pp. F33- F37, Sep. 2001.
[8] J.-T. Tsai, 2005,”在隨機短期訊號衰減和可控制多穩態高斯干擾傳輸頻道上的機會式服務排程法則”, proposal 2005 for the National Science Council of Taiwan.
[9] J.-T. Tsai, 2004,“寬頻分碼多工無線多媒體訊務下傳服務中具有融合通道狀態與選擇傳送天線特性的排程法則(一)” by the National Science Council of Taiwan under grant NSC 93-2213-E-003-007
[10] P. Bender, P. Black, M. Grob, R. Padovani, N. Sindhushayana, and A. Viterbi, “CDMA/HDR: a bandwidth-efficient high-speed wireless data service for nomadic users”, IEEE Communications Magazine, pp. 70- 77, July, 2000.
[11] Qualcomm, Inc., “1xEV: 1x evolution IS-856 TIA/EIA standard airlink overview”, Nov 7, 2001, Revision 7.2
[12] S. Shin, K. Lee, and K. Kim, “Performance of the packet data transmission using the other-cell-interference factor in DS/CDMA”, in Proc. IEEE Wireless Communications and Networking Conference (WCNC), vol. 1, pp 400- 404, Mar, 2002.
[13] S.-Y. Yun, J.-S. Lim, “An efficient power and rate control mechanism of CDMA forward link for high-speed data services”, in Proc. in Proc. Vehicular Technology Conference (VTC)-Spring, pp 607-610, 2002.
[14] S.-Y. Yun, S.-O. Bae, J.-S. Lim, “Zone-based power control scheme for multi-cell interference environments”, in Proc. Vehicular Technology Conference (VTC)-Spring, pp 2903-2907, 2001.
[15] T. Bonald, A. Proutire, “Wireless downlink data channels: user performance and cell dimensioning”, in Proc. ACM/IEEE MOBICOM, pp.339- 352, 2003.
[16] T. Bonald, S. Borst, N. Hegde, A. Proutire, ”Wireless data performance in multi-cell scenarios”, in Proc. of the joint international conference on Measurement and modeling of computer systems, pp. 378- 388, 2004.
[17] Y. Ofuji, A. Morimoto, S. Abeta, M. Sawahashi, “Comparison of packet scheduling algorithms focusing on user throughput in high speed downlink packet access”, in Proc. Personal, Indoor and Mobile Radio Communications (PIMRC), pp 1462-1466, 2002.
[18] ZHANG Xin and Yang Da-cheng, “Analysis of performance of proportional fair algorithm with reduced scheduling overhead”, in Proc. Vehicular Technology Conference (VTC)-Fall, vol. 3, pp.1663- 1667, Oct. 2003.