Third generation of mobile communications systems (3G) integrate a wide variety of wireless services as multimedia services. Universal Mobile Telecommunications System (UMTS) is the main standard of 3G with WCDMA air interface. The CDMA provides both error detection and error correction as channel coding scheme. The first one is provided by Cyclic Redundancy Check (CRC) coding and the latter by a combination convolution code with turbo decoding. For convolution coding, both soft and hard decision is considered This paper gives simulation observations of convolution coding effect on forward link (downlink) for voice and video service. The results are compared with and without utility based CAC scheme of WCDMA technology and its channel convolution coding soft and hard decision scheme.

1. Harri Holma and Antti Toskala, “WCDMA for UMTS, Radio access for third generation mobile communications”, Third Edition, John Wiley and Sons, UK, May 2001.
2. Jeffrey Bannister, Paul Mather and Sebastian Coope “Convergence Technologies for 3G Networks IP, UMTS, EGPRS and ATM,” John Wiley & Sons Ltd, 2004.
3. J. Laiho, A. Wacker, and T. Novosad, “Radio Network Planning and Optimization for UMTS”, John Wiley & Sons, Inc., England, 2002.
4. Rich Ling “THE MOBILE CONNECTION The Cell Phone’s Impact on Society,” Morgan Kaufmann Publishers, San Francisco 2004.
5. Salman A. AlQahtani and Ashraf S. Mahmoud , “Uplink Call Admission schemes for 3G and Beyond Mobiles Wireless Networks Supporting Heterogeneous Traffic,” Proceedings of IEEE International conference on Information and Communication from Theory to Application, Damascus, Syria, vol. 2, pp. 2657-2662, Jan. 2006.
6. Alma Skopljak Ramović “The Modification of WCDMA Capacity,” 16th Telecommunications Forum TELFOR 2008, Belgrade, Serbia, pp. 266 – 269, Nov. 2008.
7. B Christer V Johansson “Packet Data Capacity in a Wideband CDMA System,” 48th IEEE conference on Vehicular Technology, Stockholm. Sweden, Vol. 3.No.18, pp 1878 -1883, May, 1998.
8. Maan A. S. Al-Adwany “A Study on Cell Capacity in WCDMA & TDMA Systems,” IEEE International Workshop on Radio-Frequency Integration Technology, Singapore, pp 270-273, Dec, 2007.
9. Hedge and E. Altman “Capacity of multiservice WCDMA networks with variable GoS,” IEEE Wireless Communications and Networking Conference, vol. 2, pp. 1402–1407, 16-20 March 2003
10. Hongyang Bing, Chen He, Linqqe Jiang, “Performance analysis of vertical handover in a UMTS-WLAN integrated network,” Proceedings of IEEE conference on Personal, Indoor and Mobile Radio Communications, Beijing, China, Vol. 1, pp. 187-191, Sept. 2003.
11. Shuxian Jin, Guozhi Song and Cuthbert L, “Performance comparison of vertical handover between WCDMA/WLAN and TD-SCDMA/WLAN interworking systems”, Proceedings of IEEE Annual Conference, Aalaborg, Denmark, pp.1-5, Feb. 2008.
12. Capone A and Redana S, “Performance of Call admission control techniques for TD-SCDMA Systems,” Proceedings of IEEE conference on Vehicular Technology, Florida, USA, vol.3, pp. 1673-1677, Oct. 2003.
13. Jian Ni, Danny H. K. Tsang, Sekhar Tatikonda, and Brahim Bensaou, “Optimal and Structured Call Admission Control Policies for Resource-Sharing Systems,” IEEE Transactions on communications, vol. 55, no.1, pp. 158 – 170, Jan. 2007.
14. E. Settapong Malisuwan “Downlink Capacity of Mixed Traffic in WCDMA Mobile Internet,” International Journal of the Computer, the Internet and Management, vol. 14, No 1, pp. 1-7, Apr 2006.
15. Capone A and Redana S, “Call admission control techniques for UMTS,” Proceedings of IEEE conference on Vehicular Technology, Milan, Italy, vol.2, pp. 925-929, Oct. 2001.

Bit error rate channel coding WCDMA Voice activity factor