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Optimising CDMA Cell Planning with Soft Handover


Soft handover (SHO) is one of the fundamental features of code division multiple access (CDMA) systems such as universal mobile telecommunication system (UMTS), and it is affected by the placement and density of cells. Inclusion of soft handover in optimization models for UMTS and CDMA cell site selection and configuration has previously been very limited but it is important for coverage because it can provide gain to the user. Some authors have excluded SHO on the basis of tractability while others have found that omitting SHO in planning gives adequate solutions. As such the incorporation of SHO remains an important component for definitive investigation in optimisation models for cell planning. In this paper we focus on the problem and effect of including SHO in cell planning optimisation. We introduce a new cell planning optimisation model that explicitly incorporates SHO and reduces computational complexity. Exact results can be obtained when the orthogonality factor is zero, while a conservative approximation of interference is used to generate lower bounds on coverage in the general case. We demonstrate the tractability of this model and show that it leads to improved lower bounds for coverage maximisation in network planning.

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  1. Allen S., Smith D., Hurley S. (2002) Generation of lower bounds for minimum span frequency assignment. Discrete Applied Mathematics 119: 59–78

    MathSciNet  MATH  Article  Google Scholar 

  2. Amaldi, E., Capone, A., Malucelli, F. & Signori, F. (2002). UMTS radio planning: Optimizing base station configuration. In Proceedings of the IEEE conference on vehicular technology, Fall 2002 (pp. 768–772). Vol. 2.

  3. Amaldi E., Capone A., Malucelli F. (2003) Planning UMTS base station location: Optimization models with power control and algorithms. IEEE Transactions on Wireless Communications 2(5): 939–952

    Article  Google Scholar 

  4. Amaldi, E., Capone, A., Malucelli, F. & Signori, F. (2003b). Optimization models and algorithms for downlink UMTS radio planning. In Proceedings of the IEEE wireless communications and networking conference (pp. 827–831). Vol. 2.

  5. Amaldi E., Belotti P., Capone A., Malucelli F. (2006) Optimizing base station location and configuration in UMTS networks. Annals of Operations Research 146: 135–151

    MathSciNet  MATH  Article  Google Scholar 

  6. Berruto E., Gudmundson M., Menolascino R., Mohr W., Pizarroso M. (1998) Research activities on UMTS radio interface, network architectures, and planning. IEEE Communication Magagine 36: 82–95

    Article  Google Scholar 

  7. Calegari, P., Guidec, F., Kuonen, P., & Wagner, D. (1997). Genetic approach to radio network optimizations for mobile systems. In Proceedings of the 47th IEEE conference on vehicular technology (pp. 755–759). Vol. 2.

  8. Chamaret, B., Josselin, S., Kuonen, P., Pizarroso, M., Salas-Manzanedo, B., & Ubeda, S. (1997). Radio network optimization with maximum independent set search. In Proceedings of the IEEE VTC 1997 conference (pp. 770–774). Phoenix, AZ.

  9. Chen, Y., & Cuthbert, L. G. (2002). Genetic approach to radio network optimizations for mobile systems. In Proceedings of third international conference on 3G mobile communication technologies (pp. 47–51). London, UK.

  10. Cheung J., Beach M., McGeehan J. P. (1994) Network planning for third-generation mobile radio systems. IEEE Communication Magagine 32: 54–59

    Article  Google Scholar 

  11. Choi W., Kim J. Y. (2001) Forward-link capacity of a ds/cdma system with mixed multirate sources. IEEE Transactions on Vehicular Technology 50(3): 737–749

    Article  Google Scholar 

  12. Chopra, M., Rohani, K., & Reed, J. D. (1995). Analysis of cdma range extension due to soft handoff. In Proceedings of the IEEE VTC conference (pp. 917–921).

  13. Catrein D., Imhof L., Mathar R. (2004) Power control, capacity and duality of up- and downlink in cellular cdma systems. IEEE Transaction on Communications 52(10): 1777–1785

    Article  Google Scholar 

  14. Dai, L., Zhou, S. D., & Yao, Y. (2001). Effect of macrodiversity on cdma forward-link capacity. In Proceedings of the IEEE VTC conference (Fall), Atlantic (pp. 2452–2456).

  15. Eisenblatter, A., & Geerdes, H. (2005). Analytical approximate load control in W-CDMA radio networks. In Proceedings of the IEEE 62nd vehicular technology conference (fall), 2005.

  16. Eisenblatter, A., Wessaly, R., Martin, A., Fugenschuh, A., Wegel, O., & Koch, T. (2002). Modelling feasible network configurations for UMTS. In S.G. Anandalingam and Raghavan (Eds.), Telecommunications network design and management (Chap. 1, pp. 1–22). New York: Kluwer Academic Publishers.

  17. Eisenblatter, A., Fugenschuh, A., Geerdes, H., Junglas, D., Koch, T. & Martin, A. (2004). Integer programming methods for UMTS radio network planning. In Proceedings of the WiOpt’04 conference, Cambridge, UK.

  18. Eisenblatter A., Geerdes H. F., Koch T., Martin A., Wessaly R. (2006) UMTS radio network evaluation and optimization beyond snapshots. Mathematical Methods of Operations Research 63: 1–29

    MathSciNet  Article  Google Scholar 

  19. Eisenblatter, A., Fugenschuh, A., Fledderus, E. R., Geerdes, H. F., Heideck, B., & Junglas, D. (2003). Mathematical methods for automatic optimisation of UMTS radio networks. MOMENTUM PROJECT REPORT (Section 6.7),

  20. Fangqing, G., Hailin, L., & Ming, L. (2009). Evolutionary algorithm for the radio planning and coverage optimization of 3G cellular networks. In International Conference on Computational Intelligence and Security, Washington DC (pp. 109–113). Vol. 2.

  21. Galota, M., Glasser, C., Reith, S., & Vollmer, H. (2001). A polynomial-time approximation scheme for base station positioning in UMTS networks. In Proceedings of the 5th international workshop on discrete algorithms and methods for mobile computing and communications (pp. 52–59). Rome, Italy.

  22. Garzia F., Perna C., Cusani R. (2010) Optimization of UMTS network planning using genetic algorithms. Communications and Network 2: 193–199

    Article  Google Scholar 

  23. Gerdenitsch, A., Jakl, S., Toeltsch, M., & Neubauer, T. (2002). Intelligent algorithms for system capacity optimization of umts fdd networks. In Proceedings of IEEE 4th international conference on 3G mobile communication technology (pp. 222–226). London, UK.

  24. Ghosh S. C., Sinha B. P., Das N. (2006) Coalesced cap: An improved technique for frequency assignment in cellular networks. IEEE Tansaction on Vehicular Technology 55: 640–653

    Article  Google Scholar 

  25. Hata M. (1980) Empirical formula for propagation loss in land mobile radio services. IEEE Transactions on Vehicular Technology 29(3): 317–323

    MathSciNet  Article  Google Scholar 

  26. Holma H., Toskala A. (2000) WCDMA for UMTS. Wiley, New York

    Google Scholar 

  27. ILOG, SA. CPLEX 11.0 reference manual (2007).

  28. Ismail, M., & Aripin, N. (2005) Downlink soft handover performance for different cell selection schemes in wcdma system. In Proceedings of the 13th IEEE international conference on networks (Jointly held with the 2005 IEEE 7th Malaysia international conference on communication) (pp. 808–811). Vol. 2.

  29. Kim D. (1999) A simple algorithm for adjusting cell-site transmitter power in cdma cellular system. IEEE Transaction on Vehicular Technology 48(4): 1092–1098

    Article  Google Scholar 

  30. Kim, J. Y., & Stuber, G., (2002). Cdma soft handoff analysis in the presence of power control error and shadowing correlation. IEEE Transaction on Wireless Communications, 1.

  31. Kim, S. L., Rosberg, Z., & Zander, J. (1999). Combined power control and transmission rate selection in cellular networks. In Proceedings of IEEE VTC, Amsterdam, NL.

  32. Lee C., Kang H. (2000) Cell planning with capacity expansion in mobile communications: A tabu search approach. IEEE Transactions on Vehicular Technology 49(5): 1678–1691

    Article  Google Scholar 

  33. Lee C. C., Steele R. (1998) Effects of soft and softer handoffs on cdma system capacity. IEEE Transactions on Vehicular Technology 4: 830–841

    Google Scholar 

  34. Mathar R., Niessen T. (2000) Optimum positioning of base stations for cellular radio networks. Wireless Networks 6: 421–428

    MATH  Article  Google Scholar 

  35. Mathar R., Schmeink M. (2001) Optimal base station positioning and channel assignment for 3G mobile networks by integer programming. Annals of Operations Research 107: 225–236

    MathSciNet  MATH  Article  Google Scholar 

  36. Mathar R., Schmeink M. (2002) Integrated optimal cell site selection and frequency allocation for cellular radio networks. Telecommunication Systems 21: 339–347

    Article  Google Scholar 

  37. Menolascino, R., Pizarroso, M., Lepschy, C., & Salas, B. (1998). Third generation mobile systems planning issues. In Proceedings of the IEEE VTC’98 conference (pp. 830–834).

  38. Mihailescu, C., Lagrange, X., & Godlewski, P. (1999a). Radio resource management for packet transmission in umts wcdma systems. In Proceedings of IEEE VTC, Amsterdam, NL.

  39. Mihailescu, C., Lagrange, X., & Godlewski, P. (1999b). Soft handover analysis in downlink umts wcdma systems. In Proceedings of IEEE MOMUC, San Diego, CA.

  40. Naghshineh M., Katzela I. (1996) Channel assignment schemes for cellular mobile telecommunication systems: A comprehensive survey. IEEE Personal Communications 3: 10–31

    Article  Google Scholar 

  41. Raisanen L., Whitaker R.M. (2005) Comparison and evaluation of multiple objective genetic algorithms for antenna placement. Mobile Networks and Applications Journal 10: 79–88

    Article  Google Scholar 

  42. Schroder, B., & Weller, A. (2002). Prediction of the connection stability of umts-services in the downlink: An analytical approach. In Proceedings of IEEE VTC Fall, Vancouver, CA.

  43. Siomina, I., & Yuan, D. (2004). Pilot power optimization in wcdma networks. In Proceedings of WiOpt 04, Cambridge, UK.

  44. Staehle, D., Leibnitz, K., & Heck, K. (2002). Effects of soft handover on the umts downlink performance. In Proceedings of the IEEE 56th vehicular technology conference, VTC-2002-Fall (pp. 960–964). Vol. 2.

  45. Technical Specification Group Radio Access Network 3GPP, TS 25.214. (2006). Physical layer procedures (FDD), Version 6.7.0.

  46. Turke, U., Perera, R., Lamers, E., Winter, T., & Gorg, C. (2003). An advanced approach for qos analysis in umts radio network planning. In Proceedings of the 18th ITC, VDE (pp. 91–100).

  47. Varbrandt, P., & Yuan, D. (2003). A mathematical programming approach for pilot power optimization in wcdma networks. In Proceedings of the ATNAC 2003, Melbourne, Australia.

  48. Viterbi A. J. (1995) CDMA: Priciples of spread spectrum mmmunication. Addison-Wesley, Boston, pp 218–224

    Google Scholar 

  49. Viterbi A. J., Viterbi A. M., Gilhousen K.S., Zehavi E. (1994) Soft handoff extends cdma cell coverage and increases reverse link capacity. IEEE Journal on Selected Areas in Communications 12: 1281–1288

    Article  Google Scholar 

  50. Wang, L. C., Liao, C. Y., & Chang, C. J. (2002). Downlink soft handover and power allocation for cdma heterogeneous cellular networks. In Proceedings of the global telecommunications conference (pp. 1830–1834).

  51. Wong, D., & Lim, T. J. (1997). Soft handoffs in cdma mobile systems. IEEE Personal Communications, 6–17.

  52. Wang, L. C., & Chen, L. (2005). Outage probability analysis of downlink power allocation mechanisms in CDMA systems during soft handoff. In Proceedings of vehicular technology conference, VTC 2005-Fall (pp. 132–136).

  53. Whitaker R. M., Allen S. M., Hurley S. (2009) Efficient offline coverage and load evaluation for CDMA network modeling. IEEE Transactions on Vehicular Technology 58(7): 3704–3712

    Article  Google Scholar 

  54. Whitaker R. M., Raisanen L., Hurley S. (2005) The infrastructure efficiency of cellular wireless networks. Computer Networks Journal 48(6): 941–959

    Article  Google Scholar 

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Correspondence to Sasthi C. Ghosh.

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Ghosh, S.C., Whitaker, R.M., Allen, S.M. et al. Optimising CDMA Cell Planning with Soft Handover. Wireless Pers Commun 68, 321–347 (2013).

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  • Cell planning
  • Soft handover
  • Power control
  • Radio network design
  • UMTS
  • CDMA
  • Fade margin